Reconstructing Holocene palaeo-environmental conditions in the Baltic: A multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)

NASA Astrophysics Data System (ADS)

Kotthoff, Ulrich; Andrén, Elinor; Andrén, Thomas; Ash, Jeanine; Bauersachs, Thorsten; Fanget, Anne-Sophie; Granoszewski, Wojciech; Groeneveld, Jeroen; Krupinski, Nadine; Peyron, Odile; Slomp, Caroline; Stepanova, Anna; Warnock, Jonathan; van Helmond, Niels; Expedition 347 Science Party

2016-04-01

Some of the largest marine environmental impacts from ongoing global climate change are occurring in continental shelf seas and enclosed basins, including severe oxygen depletion, intensifying stratification, and increasing temperatures. In order to predict future changes in water mass conditions, it is essential to reconstruct how these conditions have changed in the past against the background of climate changes. The brackish Baltic Sea is one of the largest semi-enclosed basins worldwide, and its sediment records provide a unique opportunity to analyse palaeo-environmental and climate change in central and northern Europe. IODP Expedition 347 recovered an exceptional set of sediment cores from the Baltic Sea which allow high-resolution reconstructions in unprecedented quality. We present a comparison of commonly-used proxies to reconstruct palaeoecosystems, -temperatures, and -salinity from IODP Site M0059 in the Little Belt over the past ˜8000 years. Our aim is to reconstruct the development of the terrestrial and marine ecosystems in the research area and the related environmental conditions, and to identify potential limitations of individual proxies. The age model for Site M0059 is based on 14Cdating, biostratigraphic correlation with neighbouring terrestrial pollen records, and sediment stratigraphy. Sedimentary organic carbon content and the bulk elemental composition have been measured, and can be used to determine the depositional environment and degree of oxygen depletion (e.g., Mo, Corg/Ptot). Pollen is used as proxy for vegetation development in the hinterland of the southern Baltic Sea and as a land/air-temperature proxy. Comparison with dinoflagellate cysts, insect remains, and green algae remains from the same samples provides a direct land-sea comparison. The application of the modern analogues technique to pollen assemblages has previously yielded precise results for late Pleistocene and Holocene datasets, including specific information on seasonality, but pollen-based reconstructions for Northern Europe may be hampered by plant migration effects. Palynomorph analyses are therefore complemented with analyses of lipid palaeothermometers, such as TEX86 and the long chain diol index (LDI), to reconstruct variations in Baltic Sea surface temperatures (SST). In addition, the MBT/CBT proxy is used to infer past changes in mean annual air temperatures (MAAT). Benthic foraminiferal δ18O and δ13C measurements (monospecific) and foraminifera and ostracod faunal assemblage analyses allow us to estimate bottom water salinity and environmental changes qualitatively and quantitatively. Low bottom water salinity (˜23 in bottom waters) and varying diagenesis in the Little Belt's organic-rich sediments complicates the application of benthic foraminiferal Mg/Ca as a palaeotemperature proxy. Reliable bottom water temperatures, however, are reconstructed using clumped isotope analyses of mollusc material. In addition, diatoms and the diol index (DI) are analysed to determine variation in salinity of the Baltic Sea's surface waters over the investigated time period. The results of this inter-proxy comparison study will be used to reconstruct gradients between different settings, e.g. how water column stratification developed, possibly if and how changes in seasonality occurred, and to identify the circumstances under which specific proxies may be affected by secondary impacts.

Precipitation variability inferred from the annual growth and isotopic composition of tropical trees

NASA Astrophysics Data System (ADS)

Ballantyne, A. P.; Baker, P. A.; Chambers, J. Q.; Villalba, R.

2005-12-01

Here we demonstrate that annual growth and isotopic ratios in tropical trees are responsive to seasonal and annual precipitation variability. We identify several regions of tropical South America characterized by significant relationships between oxygen isotopic ratios (δ 18O) in precipitation and precipitation amount (r = -0.82). Many of these regions are also sensitive to inter-annual variability in the South American Monsoon modulated by the El Niño Southern Oscillation (ENSO). The effectiveness of δ 18O and annual growth of tropical trees as a precipitation proxy is validated by high-resolution sampling of a Tachigali vermelho tree growing near Manaus, Brazil (3.1° S, 60.0° S). Growth in Tachigali spp. was highly correlated with both precipitation and cellulose δ 18O (r = 0.60) and precipitation amount was significantly correlated with δ 18O at a lag of approximately one month (r = 0.56). We also report a multi-proxy record spanning 180 years from Cedrela odorata growing in the Peruvian Amazon near Puerto Maldonado (12.6° S, 69.2° W) revealing a significant relationship between cellulose and monsoon precipitation over the region (r = -0.33). A 150-year record obtained from Polylepis tarapacana growing at Volcan Granada in Northern Argentina (22.0° S, 66.0° W) is also reported with a significant relationship between local monsoon precipitation and a regionally derived ring width index (r = 0.38). Although no significant relationship was revealed between cellulose δ 18O and precipitation in this taxa at this location, separate radii within the same tree revealed a significantly coherent δ 18O signal (r = 0.38). We compared our proxy chronologies with monsoon precipitation reanalysis data for tropical South America, which revealed key features of the South American Monsoon and their sensitivity to ENSO variability.

Multi-proxies Approach of Climatic Records In Terrestrial Mollusks Shells

NASA Astrophysics Data System (ADS)

Labonne, M.; Rousseau, D. D.; Ben Othman, D.; Luck, J. M.; Metref, S.

Fossil land snails shells constitute a valuable source of information for the study of Quaternary deposits as they are commonly preserved in many regions and notably in loess sequences. The use of stable isotope composition of the carbonate in the shells was previously applied to reconstruct past climate or environnements but the technic was not widely exploited and compared with other proxies from the same sequence. In this study, we have analysed stables isotopes, trace elements and Sr isotopes from both shells of land snails Vertigo modesta and the sediment from the Eustis upper Pleistocene loess sequence (Nebraska, USA). This serie developed during the last glaciation and records the last deglaciation between 18,000 and 12,000 B.P. years. We compare the paleoclimatic information obtained by different proxies, such as mag- netic susceptibility, temperature and moisture estimated by land snails assemblage with geochemical data measured on land snails shells in order to validate the climatic information obtained with this proxy. Our study demonstrates that shell carbonate reflects environmental conditions estimated by other proxies. Carbon and oxygen iso- topes show cyclic variations (millenial cycles) along the profile which correlate with stratigraphic units and could be link with the retreat of the Laurentide ice sheet. Trace element and Sr isotopes in the shells indicate various origins for the eolian dusts in the two main loess units along the sequence.

Is Recent Warming Unprecedented in the Common Era? Insights from PAGES2k data and the Last Millennium Reanalysis

NASA Astrophysics Data System (ADS)

Erb, M. P.; Emile-Geay, J.; McKay, N.; Hakim, G. J.; Steig, E. J.; Anchukaitis, K. J.

2017-12-01

Paleoclimate observations provide a critical context for 20th century warming by putting recent climate change into a longer-term perspective. Previous work (e.g. IPCC AR3-5) has claimed that recent decades are exceptional in the context of past centuries, though these statements are usually accompanied by large uncertainties and little spatial detail. Here we leverage a recent multiproxy compilation (PAGES2k Consortium, 2017) to revisit this long-standing question. We do so via two complementary approaches. The first approach compares multi-decadal averages and trends in PAGES2k proxy records, which include trees, corals, ice cores, and more. Numerous proxy records reveal that late 20th century values are extreme compared to the remainder of the recorded period, although considerable variability exists in the signals preserved in individual records. The second approach uses the same PAGES2k data blended with climate model output to produce an optimal analysis: the Last Millennium Reanalysis (LMR; Hakim et al., 2016). Unlike proxy data, LMR is spatially-complete and explicitly models uncertainty in proxy records, resulting in objective error estimates. The LMR results show that for nearly every region of the world, late 20th century temperatures exceed temperatures in previous multi-decadal periods during the Common Era, and 20th century warming rates exceed rates in previous centuries. An uncertainty with the present analyses concerns the interpretation of proxy records. PAGES2k included only records that are primarily sensitive to temperature, but many proxies may be influenced by secondary non-temperature effects. Additionally, the issue of seasonality is important as, for example, many temperature-sensitive tree ring chronologies in the Northern Hemisphere respond to summer or growing season temperature rather than annual-means. These uncertainties will be further explored. References Hakim, G. J., et al., 2016: The last millennium climate reanalysis project: Framework and first results. Journal of Geophysical Research: Atmospheres, 121(12), 6745-6764. http://doi.org/10.1002/2016JD024751 PAGES2k Consortium, 2017: A global multiproxy database for temperature reconstructions of the Common Era. Scientific Data, 1-33. http://doi.org/10.1038/sdata.2017.88

Urban political ecologies of informal recyclers׳ health in Buenos Aires, Argentina.

PubMed

Parizeau, Kate

2015-05-01

Buenos Aires׳ informal recyclers (cartoneros) confront multiple health hazards in their work. Based in a survey with (n=397) informal recyclers, this study establishes that these workers experience uneven health landscapes as evidenced through their health outcomes, the social determinants of their health, and their living and working environments. I argue that the analytical framework of urban political ecology can provide insights to the ways that the urban environments where cartoneros live and work are socially-constructed phenomena, drawing on concepts of crisis, metabolism, and multi-scalar analyses. Copyright © 2015 Elsevier Ltd. All rights reserved.

Paleosol Proxies for Low Elevation Paleoclimate East of the Andes, Northwestern Argentina

NASA Astrophysics Data System (ADS)

Rosario, J. J.; Jordan, T. E.; Garzione, C. N.; Higgins, P.; Hernandez, R.; Hernandez, J.

2009-12-01

Paleosols can be used as a proxy for paleoclimate, paleoenvironment, and geomorphological reconstructions. The weathering imprint in the minerals in paleosols can be used as a proxy for moisture conditions, while other environmental information can be obtained from stable isotopes in their minerals such as δ13C and δ18O. The goal of this study is to document changes in paleosol characteristics’ driven by climate change in NW Argentina over the time period between ~14 Ma and 5.1 Ma during a time of significant uplift and climate change in the Altiplano. During this time interval, landscape of the low elevation foreland basin changed as the consequence of the propagation of Andean thrust-fold deformation. Paleosols are interbedded in three stratigraphic sections that are described, sampled, and studied along the Iruya, Peña Colorada, and La Porcelana rivers, distributed from west to east, respectively. Field observations of the paleosols, stratigraphic column construction, thin section petrography and textures, x-ray diffraction (XRD), and stable isotopes together provide climatic proxies. These The stratigraphic columns represent a distributary depositional system, or megafan, whose syn-deformational nature is documented by Echevarría et al. (2003). Argillic-calcic paleosols developed on silty and sandy mudstones in the floodplain environment, with pedogenic calcium carbonate formed as nodules and rizoliths. The Microscopic features show that paleosols on the floodplain contain argillans. Semi-humid to semi-arid conditions are suggested by clay lessivage and calcium carbonate precipitation respectively. The mineralogy reflected by the XRD shows kaolinite, illite, and calcium carbonate in the western stratigraphic column that represents moderate climatic conditions (semi-humid to semi-arid). The coexistence of these minerals suggests seasonal variations in moisture. The eastern columns exhibit wetter soil conditions, including oxide minerals as well as hematite and goethite. Carbon isotopes show C3 vegetation with an increase in δ13C values most likely resulting from increasing seasonality in more recent times. There is little variation in δ18O values through time. In conclusion, these proxies show that soils were developed on interchannel areas, with illuviation of clays during the wet season and precipitation of calcium carbonate during the dry season. Although the megafan migrated eastward and the Altiplano rose, oxygen isotopes suggest that neither rainfall amount nor source of water vapor changed through the approximately 10 million years time interval.

Cretaceous honeycomb oysters (Pycnodonte vesicularis) as palaeoseasonality records: A multi-proxy study

NASA Astrophysics Data System (ADS)

de Winter, Niels J.; Vellekoop, Johan; Vorsselmans, Robin; Golreihan, Asefeh; Petersen, Sierra V.; Meyer, Kyle W.; Speijer, Robert P.; Claeys, Philippe

2017-04-01

Pycnodonte or "honeycomb-oysters" (Bivalvia: Gryphaeidea) is an extinct genus of calcite-producing bivalves which is found in abundance in Cretaceous to Pleistocene fossil beds worldwide. As such, Pycnodonte shells could be ideal tracers of palaeoclimate through time, with the capability to reconstruct sea water conditions and palaeotemperatures in a range of palaeoenvironmental settings. Only few studies have attempted to reconstruct palaeoclimate based on Pycnodonte shells and with variable degrees of success (e.g. Videt, 2003; Huyge et al., 2015). Our study investigates the shell growth, structure and chemical characteristics of Maastrichtian Pycnodonte vesicularis from Bajada de Jaguel in Argentina and aims to rigorously test the application of multiple palaeoenvironmental proxies on the shells of several Maastrichtian Pycnodonte oysters for palaeoclimate reconstruction. The preservation state of four calcite shells was assessed by fluorescence microscopy, cathodoluminescence and micro X-Ray Fluorescence (XRF) mapping. Their shell structure was investigated using a combination of XRF mapping, high-resolution color scanning and microCT scanning. Long integration time point-by-point XRF line scanning yielded high-resolution trace element profiles through the hinge of all shells. Microdrilled samples from the same locations on the shell were analyzed for trace element composition by ICP-MS and for stable carbon and oxygen isotopes by IRMS. Preservation of the calcite microstructure was found to be of sufficient quality to allow discussion of original shell porosity, annual growth increments and pristine chemical signatures of the bivalves. The combination of fluorescence and cathodoluminescence microscopy with XRF mapping and microCT scanning sheds light on the characteristic internal "honeycomb" structure of these extinct bivalves and allows comparison with that of the related extant Neopycnodonte bivalves (Wisshak et al., 2009). Furthermore, high resolution trace element and stable isotope records allow discussion of the degree to which Pycnodonte shells record their palaeoenvironment and can be used to reconstruct past sea water conditions. Preliminary results indicate that stable isotope and trace element ratios in Pynodonte shells record different seasonally changing sea water conditions in the Maastrichtian and reconstructed temperatures are consistent with results from clumped isotope analysis on the same shells and TEX86 analysis on the surrounding rocks. This multi-proxy study sheds light on the shell structure of Pycnodonte oysters, their chemical signature and growth pattern and investigates the expression of palaeoenvironmental proxies in the pristine shell calcite of these bivalves. This investigation shows the potential of using fossil Pycnodonte bivalves as a new archive for palaeoclimate reconstruction on a seasonal scale over a wide range of palaeolatitudes from the Cretaceous until the Pleistocene. References Huyghe et al. (2015) J. Geol Soc 172.5: 576-587. Videt (2003) Diss. Université Rennes 1. Wisshak, et al. (2009) Deep-Sea Res Pt I 56.3: 374-407.

A New Quantum Proxy Multi-signature Scheme Using Maximally Entangled Seven-Qubit States

NASA Astrophysics Data System (ADS)

Cao, Hai-Jing; Zhang, Jia-Fu; Liu, Jian; Li, Zeng-You

2016-02-01

In this paper, we propose a new secure quantum proxy multi-signature scheme using seven-qubit entangled quantum state as quantum channels, which may have applications in e-payment system, e-government, e-business, etc. This scheme is based on controlled quantum teleportation. The scheme uses the physical characteristics of quantum mechanics to guarantee its anonymity, verifiability, traceability, unforgetability and undeniability.

Using multi-resolution proxies to assess ENSO impacts on the mean state of the tropical Pacific.

NASA Astrophysics Data System (ADS)

Karamperidou, C.; Conroy, J. L.

2016-12-01

Observations and model simulations indicate that the relationship between ENSO and the mean state of the tropical Pacific is a two-way interaction. On one hand, a strong zonal SST gradient (dSST) in the Pacific (colder cold tongue) increases the potential intensity of upcoming ENSO events and may lead to increased ENSO variance. On the other hand, in a period of increased ENSO activity, large events can warm the cold tongue at decadal scales via residual heating, and thus lead to reduced zonal SST gradient (ENSO rectification mechanism). The short length of the observational record hinders our ability to confidently evaluate which mechanism dominates in each period, and whether it is sensitive to external climate forcing. This question is effectively a question of interaction between two timescales: interannual and decadal. Paleoclimate proxies of different resolutions can help elucidate this question, since they can be independent records of variability in these separate timescales. Here, we use coral proxies of ENSO variability from across the Pacific and multi-proxy records of dSST at longer timescales. Proxies, models, and observations indicate that in periods of increased ENSO activity, dSST is negatively correlated with ENSO variance at decadal timescales, indicating that strong ENSO events may affect the decadal mean state via warming the cold tongue. Using climate model simulations we attribute this effect to residual nonlinear dynamical heating, thus supporting the ENSO rectification mechanism. On the contrary, in periods without strong events, ENSO variance and dSST are positively correlated, which indicates that the primary mechanism at work is the effect of the mean state on ENSO. Our analysis also quantitatively identifies the regions where paleoclimate proxies are needed in order to reduce the existing uncertainties in ENSO-mean state interactions. Hence, this study is a synthesis of observations, model simulations and paleoclimate proxy evidence guided by the fundamental and open question of multi-scale interactions in the tropical Pacific, and illustrates the need for multi-resolution paleoclimate proxies and their potential uses.

Quantum Proxy Multi-Signature Scheme Using Genuinely Entangled Six Qubits State

NASA Astrophysics Data System (ADS)

Cao, Hai-Jing; Wang, Huai-Sheng; Li, Peng-Fei

2013-04-01

A quantum proxy multi-signature scheme is presented based on controlled teleportation. Genuinely entangled six qubits quantum state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement delegation, signature and verification. Quantum key distribution and one-time pad are adopted in our scheme, which could guarantee not only the unconditional security of the scheme but also the anonymity of the messages owner.

Benthic macroinvertebrate field sampling effort required to produce a sample adequate for the assessment of rivers and streams of Neuquén Province, Argentina

EPA Science Inventory

This multi-year pilot study evaluated a proposed field method for its effectiveness in the collection of a benthic macroinvertebrate sample adequate for use in the condition assessment of streams and rivers in the Neuquén Province, Argentina. A total of 13 sites, distribut...

Extreme Wave Deposits On The Pacific Coast Of Mexico: Tsunamis Or Storms? - A Multi-Proxy Approach

NASA Astrophysics Data System (ADS)

Ramirez Herrera, M.; Lagos, M.; Hutchinson, I.; Chague-Goff, C.; Kostoglodov, V.; Goff, J. R.; Ruiz-Fernandez, A.; Machain, M.; Caballero, M.; Goguitchaichrili, A.; Aguilar, B.; Urquijo, P.; Laboratorio Universitario de Geofísica Ambiental (Luga)

2011-12-01

Historical and instrumental data show that the Pacific coast of Mexico has been exposed to destructive tsunamis over at least the past 500 years. This coast is also affected by hurricanes generated in the eastern Pacific. The great 1985 Mexico earthquake and its aftershock generated tsunamis that affected the Ixtapa-Zihuatanejo and Michoacán coast. The purpose of our study was two-fold, a) to determine whether we could distinguish storm from tsunami deposits, and b) whether tsunami deposits from historical events are preserved in the tropical environments of the Ixtapa-Zihuatanejo coast. Two anomalous sand units in the Ixtapa estuary are interpreted as the result of high-energy marine inundation events that occurred in the last century. Several lines of evidence using a multi-proxy approach (historical studies, interviews with local witnesses, geomorphological and geological surveys, coring and trenching, and laboratory analyses including grain size, micropaleontology, geochemistry, magnetic susceptibility and radiometric dating) indicate the occurrence of two tsunamis that we link to local events: the 1985 Mexico and possibly the 1979 Petatlan earthquakes. We thereby provide the first onshore geological evidence of historical tsunamis on the Pacific coast of Mexico.

Resilience, rapid transitions and regime shifts: fingerprinting the responses of Lake Żabińskie (NE Poland) to climate variability and human disturbance since 1000 AD

NASA Astrophysics Data System (ADS)

Tylmann, Wojciech; Hernández-Almeida, Iván; Grosjean, Martin; José Gómez Navarro, Juan; Larocque-Tobler, Isabelle; Bonk, Alicja; Enters, Dirk; Ustrzycka, Alicja; Piotrowska, Natalia; Przybylak, Rajmund; Wacnik, Agnieszka; Witak, Małgorzata

2016-04-01

Rapid ecosystem transitions and adverse effects on ecosystem services as responses to combined climate and human impacts are of major concern. Yet few quantitative observational data exist, particularly for ecosystems that have a long history of human intervention. Here, we combine quantitative summer and winter climate reconstructions, climate model simulations and proxies for three major environmental pressures (land use, nutrients and erosion) to explore the system dynamics, resilience, and the role of disturbance regimes in varved eutrophic Lake Żabińskie since AD 1000. Comparison between regional and global climate simulations and quantitative climate reconstructions indicate that proxy data capture noticeably natural forced climate variability, while internal variability appears as the dominant source of climate variability in the climate model simulations during most parts of the last millennium. Using different multivariate analyses and change point detection techniques, we identify ecosystem changes through time and shifts between rather stable states and highly variable ones, as expressed by the proxies for land-use, erosion and productivity in the lake. Prior to AD 1600, the lake ecosystem was characterized by a high stability and resilience against considerable observed natural climate variability. In contrast, lake-ecosystem conditions started to fluctuate at high frequency across a broad range of states after AD 1600. The period AD 1748-1868 represents the phase with the strongest human disturbance of the ecosystem. Analyses of the frequency of change points in the multi-proxy dataset suggests that the last 400 years were highly variable and flickering with increasing vulnerability of the ecosystem to the combined effects of climate variability and anthropogenic disturbances. This led to significant rapid ecosystem transformations.

Identifying potential differences in ontogentic ages between modern and archaeological Nacella deaurata shells, Tierra del Fuego, Argentina

NASA Astrophysics Data System (ADS)

Surge, D. M.; Godino, I. B. I.; Álvarez, M.; López, M. B. I.

2017-12-01

Patelloid limpet shells are common constituents of rocky shore habitats along the eastern Atlantic basin and are often found in archaeological shell middens. Nacella deaurata is an intertidal species found in the Magellanic Province along the southern tip of South America. Recent discoveries of archaeological shell middens in Tierra del Fuego, Argentina, identify N. deaurata as one of the abundant shells in these deposits. Preliminary observations reveal that modern N. deaurata shells achieve larger sizes compared to those found in the archaeological middens. Here, we provide preliminary data to test the hypothesis that the larger, modern specimens grow to older ontogenetic ages than the smaller archaeological specimens. Our results may provide insights into harvesting pressures on this species during the time when the archaeological sites were inhabited. Understanding their annual growth patterns also has important implications for generating oxygen isotope proxy data to reconstruct seasonal variation in sea surface temperature.

Multi-Purpose, Application-Centric, Scalable I/O Proxy Application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, M. C.

2015-06-15

MACSio is a Multi-purpose, Application-Centric, Scalable I/O proxy application. It is designed to support a number of goals with respect to parallel I/O performance testing and benchmarking including the ability to test and compare various I/O libraries and I/O paradigms, to predict scalable performance of real applications and to help identify where improvements in I/O performance can be made within the HPC I/O software stack.

Discourses and Policies on Educational Quality in Argentina, 1990-2010

ERIC Educational Resources Information Center

Gorostiaga, Jorge M.; Ferreira, Adrian

2012-01-01

This article analyses the relationships between different notions of education quality and policies on primary and secondary schools implemented in Argentina during the last two decades. The authors focus on three moments: (1) the emergence of the discussion about quality (at the end of the 1980s) in Latin America and in Argentina; (2) the…

Testing Bergmann's rule and the Rosenzweig hypothesis with craniometric studies of the South American sea lion.

PubMed

Sepúlveda, Maritza; Oliva, Doris; Duran, L René; Urra, Alejandra; Pedraza, Susana N; Majluf, Patrícia; Goodall, Natalie; Crespo, Enrique A

2013-04-01

We tested the validity of Bergmann's rule and Rosenzweig's hypothesis through an analysis of the geographical variation of the skull size of Otaria flavescens along the entire distribution range of the species (except Brazil). We quantified the sizes of 606 adult South American sea lion skulls measured in seven localities of Peru, Chile, Uruguay, Argentina, and the Falkland/Malvinas Islands. Geographical and environmental variables included latitude, longitude, and monthly minimum, maximum, and mean air and ocean temperatures. We also included information on fish landings as a proxy for productivity. Males showed a positive relationship between condylobasal length (CBL) and latitude, and between CBL and the six temperature variables. By contrast, females showed a negative relationship between CBL and the same variables. Finally, female skull size showed a significant and positive correlation with fish landings, while males did not show any relationship with this variable. The body size of males conformed to Bergmann's rule, with larger individuals found in southern localities of South America. Females followed the converse of Bergmann's rule at the intraspecific level, but showed a positive relationship with the proxy for productivity, thus supporting Rosenzweig's hypothesis. Differences in the factors that drive body size in females and males may be explained by their different life-history strategies. Our analyses demonstrate that latitude and temperature are not the only factors that explain spatial variation in body size: others such as food availability are also important for explaining the ecogeographical patterns found in O. flavescens.

Intra-to multidecadel variations of snowpack and streamflow records in the Andes of Chile and Argentina between 30 degrees and 37 degrees S.

USDA-ARS?s Scientific Manuscript database

Regional composites of winter snowpack (1951-2008) and mean annual river discharges (1906-2007) are used to evaluate the main intra- to multi-decadal hydrologic variations in the Andes of Chile and Argentina between 30° and 37°S. The streamflow record shows a non-significant negative trend but two s...

A Multi-Proxy Paradigm in the Pursuit of Ocean Paleoredox

NASA Astrophysics Data System (ADS)

Anbar, A. D.; Duan, Y.; Kendall, B.; Reinhard, C.; Severmann, S.; Lyons, T. W.

2011-12-01

The geologic record provides abundant evidence for variations in ocean oxygenation throughout Earth history. Expansion of ocean anoxic zones is expected in the future as a consequence of global climate change, with attendant effects on global nutrient inventories, carbon cycling and fluxes of trace greenhouse gases to the atmosphere. Therefore, studying ancient ocean redox variations not only teaches us about the history of the Earth system, but also provides insights into how the system may respond to analogous human perturbations. However, the extent, duration, causes, and consequences of most past variations are poorly understood. This problem motivates the development of paleoredox proxies, including novel stable isotope systems such as Mo, Fe, U and Tl. Experience with these emerging isotope systems demonstrates great promise but also many challenges. The Mo isotope system is illustrative. To first order, the geochemical cycling and isotope systematics of this element are straightforward, making it a useful proxy. However, critical unresolved issues include: (a) uncertainties in the ocean inputs through time; (b) ambiguities about fractionation mechanisms; (c) inadequate understanding of how modern analogs map to ancient systems. Similar challenges confront all the novel isotope systems. The way forward requires integration of multiple isotopic proxies, as well as information gleaned from careful analyses of element concentrations. For example, an episode of Mo enrichment in the 2.5 Ga Mt. McRae Shale is generally interpreted as resulting from buildup of Mo in seawater due to oxidative weathering. This enrichment is therefore thought to indicate a "whiff" of O2 in the environment prior to the Great Oxidation Event that began at 2.4 Ga. Molybdenum isotopes are consistent with this interpretation. However, Mo enrichment due to enhanced input from low-T hydrothermal sources in an anoxic regime cannot be completely excluded given the current state of knowledge of Mo isotope systematics from such sources. By considering sedimentary Fe enrichments together with Fe isotopes, we find that the Mo enrichment correlates with the telltale signature of a shelf-to-basin Fe redox "shuttle". Uranium isotopes also exhibit variations indicative of redox transformations. This multi-proxy dataset therefore paints a robust picture of trace metal redox cycling consistent with the "whiff" interpretation.

Proxy decision making and dementia: Using Construal Level Theory to analyse the thoughts of decision makers.

PubMed

Convey, Helen; Holt, Janet; Summers, Barbara

2018-07-01

This study explored the feasibility of using Construal Level Theory to analyse proxy decision maker thinking about a hypothetical ethical dilemma, relating to a person who has dementia. Proxy decision makers make decisions on behalf of individuals who are living with dementia when dementia affects that individual's decision making ability. Ethical dilemmas arise because there is a need to balance the individual's past and contemporary values and views. Understanding of how proxy decision makers respond is incomplete. Construal Level Theory contends that individuals imagine reactions and make predications about the future by crossing psychological distance. This involves abstract thinking, giving meaning to decisions. There is no empirical evidence of Construal Level Theory being used to analyse proxy decision maker thinking. Exploring the feasibility of using Construal Level Theory to understand dementia carer thinking regarding proxy decisions may provide insights which inform the support given. Descriptive qualitative research with semi-structured interviews. Seven participants were interviewed using a hypothetical dementia care scenario in February 2016. Interview transcripts were analysed for themes. Construal Level Theory was applied to analyse participant responses within themes using the Linguistic Category Model. Participants travelled across psychological distance, using abstract thinking to clarify goals and provide a basis for decisions. When thinking concretely participants established boundaries regarding the ethical dilemma. Construal Level Theory gives insight into proxy decision maker thinking and the levels of abstraction used. Understanding what dementia carers think about when making proxy decisions may help nurses to understand their perspectives and to provide appropriate support. © 2018 John Wiley & Sons Ltd.

Changes in mid to late Holocene monsoon strength in eastern Mexico inferred from high-resolution maar lake sediments

NASA Astrophysics Data System (ADS)

Bhattacharya, T.; Byrne, R.; Wogau, K.; Bohnel, H.

2013-12-01

Understanding the Holocene variation in central Mexico's summer precipitation can help identify the processes responsible for climatic change and clarify the role of climate in Mesoamerican cultural change. We present proxy results from Aljojuca, a maar lake in the Oriental-Serdan Basin in Mexico's Trans-Mexican Volcanic Belt. The 12 m sediment core from Aljojuca features a laminated, high-resolution proxy archive. A chronology established via radiocarbon dating shows a basal date of 6,200 cal. years B.P. We use fluctuations in pollen, elemental geochemistry, and the stable isotope ratios of authigenic carbonates to reconstruct the timing and duration of mid to late Holocene droughts in central Mexico. We compare these results with geochemical analyses of maar wall rocks and palynological analyses of modern moss polsters to strengthen our interpretations of proxy results. We interpret periods of aridity as periods of reduced summer precipitation and therefore decreased summer monsoon strength. Our results reveal evidence of a gradual decrease in monsoon strength from the mid to late Holocene. We also identify a multi-century dry period between 1,150 and 800 cal yr. BP, coinciding with the abandonment of the nearby fortified city of Cantona. Spatiotemporal analysis of this and other paleoclimatic records reveals region-wide evidence of this ';Terminal Classic' drought, although its timing is spatially heterogeneous. Our results represent one of the only high-resolution mid-Holocene records from the eastern Trans-Mexican Volcanic Belt.

Deciphering Late-Pleistocence landscape evolution: linking proxies by combining pedo-stratigraphy and luminescence dating

NASA Astrophysics Data System (ADS)

Kreutzer, Sebastian; Meszner, Sascha; Faust, Dominik; Fuchs, Markus

2014-05-01

Interpreting former landscape evolution asks for understanding the processes that sculpt such landforms by means of deciphering complex systems. For reconstructing terrestrial Quaternary environments based on loess archives this might be considered, at least, as a three step process: (1) Identifying valuable records in appropriate morphological positions in a previously defined research area, (2) analysing the profiles by field work and laboratory methods and finally (3) linking the previously considered pseudo-isolated systems to set up a comprehensive picture. Especially the first and the last step might bring some pitfalls, as it is tempting to specify single records as pseudo-isolated, closed systems. They might be, with regard to their preservation in their specific morphological position, but in fact they are part of a complex, open system. Between 2008 and 2013, Late-Pleistocene loess archives in Saxony have been intensively investigated by field and laboratory methods. Linking pedo- and luminescence dating based chronostratigraphies, a composite profile for the entire Saxonian Loess Region has been established. With this, at least, two-fold approach we tried to avoid misinterpretations that might appear when focussing on one standard profile in an open morphological system. Our contribution focuses on this multi-proxy approach to decipher the Late-Pleistocene landscape evolution in the Saxonian Loess Region. Highlighting the challenges and advantages of combining different methods, we believe that (1) this multi-proxy approach is without alternative, (2) the combination of different profiles may simplify the more complex reality, but it may be a useful generalisation to understand and reveal the stratigraphical significance of the landscape evolution in this region.

Rock Magnetic Properties of Laguna Carmen (Tierra del Fuego, Argentina): Implications for Paleomagnetic Reconstruction

NASA Astrophysics Data System (ADS)

Gogorza, C. G.; Orgeira, M. J.; Ponce, F.; Fernández, M.; Laprida, C.; Coronato, A.

2013-05-01

We report preliminary results obtained from a multi-proxy analysis including paleomagnetic and rock-magnetic studies of two sediment cores of Laguna Carmen (53°40'60" S 68°19'0" W, ~83m asl) in the semiarid steppe in northern Tierra del Fuego island, Southernmost Patagonia, Argentina. Two short cores (115 cm) were sampled using a Livingstone piston corer during the 2011 southern fall. Sediments are massive green clays (115 to 70 cm depth) with irregularly spaced thin sandy strata and lens. Massive yellow clay with thin sandy strata continues up to 30 cm depth; from here up to 10 cm yellow massive clays domain. The topmost 10 cm are mixed yellow and green clays with fine sand. Measurements of intensity and directions of Natural Remanent Magnetization (NRM), magnetic susceptibility, isothermal remanent magnetization, saturation isothermal remanent magnetization (SIRM), back field and anhysteretic remanent magnetization at 100 mT (ARM100mT) were performed and several associated parameters calculated (ARM100mT/k and SIRM/ ARM100mT). Also, as a first estimate of relative magnetic grain-size variations, the median destructive field of the NRM (MDFNRM), was determined. Additionally, we present results of magnetic parameters measured with vibrating sample magnetometer (VSM). The stability of the NRM was analyzed by alternating field demagnetization. The magnetic properties have shown variable values, showing changes in both grain size and concentration of magnetic minerals. It was found that the main carrier of remanence is magnetite with the presence of hematite in very low percentages. This is the first paleomagnetic study performed in lakes located in the northern, semiarid fuegian steppe, where humid-dry cycles have been interpreted all along the Holocene from an aeolian paleosoil sequence (Orgeira et el, 2012). Comparison between paleomagnetic records of Laguna Carmen and results obtained in earlier studies carried out at Laguna Potrok Aike (Gogorza et al., 2012) were performed. References Gogorza, C.S.G., Irurzun, M.A., Sinito, A.M., Lisé-Pronovost, A., St-Onge, G., Haberzettl, T., Ohlendorf, C., Kastner, S., Zolitschka, B., 2012. High-resolution paleomagnetic records from Laguna Potrok Aike (Patagonia, Argentina) for the last 16,000 years. Geochemistry Geophysics Geosystems. 13, Q12Z37. Orgeira, M.J., Vásquez, C.A., Coronato, A., Ponce, F., Moreto, A., Osterrieth, M, Egli, R., Onorato, R., 2012. Magnetic properties of Holocene edaphized silty eolian sediments from Tierra del Fuego (Argentina). Revista de la Sociedad Geológica de España. 25 (1-2), 45-56.

Continental-scale temperature covariance in proxy reconstructions and climate models

NASA Astrophysics Data System (ADS)

Hartl-Meier, Claudia; Büntgen, Ulf; Smerdon, Jason; Zorita, Eduardo; Krusic, Paul; Ljungqvist, Fredrik; Schneider, Lea; Esper, Jan

2017-04-01

Inter-continental temperature variability over the past millennium has been reported to be more coherent in climate model simulations than in multi-proxy-based reconstructions, a finding that undermines the representation of spatial variability in either of these approaches. We assess the covariance of summer temperatures among Northern Hemisphere continents by comparing tree-ring based temperature reconstructions with state-of-the-art climate model simulations over the past millennium. We find inter-continental temperature covariance to be larger in tree-ring-only reconstructions compared to those derived from multi-proxy networks, thus enhancing the agreement between proxy- and model-based spatial representations. A detailed comparison of simulated temperatures, however, reveals substantial spread among the models. Over the past millennium, inter-continental temperature correlations are driven by the cooling after major volcanic eruptions in 1257, 1452, 1601, and 1815. The coherence of these synchronizing events appears to be elevated in several climate simulations relative to their own covariance baselines and the proxy reconstructions, suggesting these models overestimate the amplitude of cooling in response to volcanic forcing at large spatial scales.

Organic Fertilization and Sufficient Nutrient Status in Prehistoric Agriculture? – Indications from Multi-Proxy Analyses of Archaeological Topsoil Relicts

PubMed Central

Lauer, Franziska; Prost, Katharina; Gerlach, Renate; Pätzold, Stefan; Wolf, Mareike; Urmersbach, Sarah; Lehndorff, Eva; Eckmeier, Eileen; Amelung, Wulf

2014-01-01

Neolithic and Bronze Age topsoil relicts revealed enhanced extractable phosphorus (P) and plant available inorganic P fractions, thus raising the question whether there was targeted soil amelioration in prehistoric times. This study aimed (i) at assessing the overall nutrient status and the soil organic matter content of these arable topsoil relicts, and (ii) at tracing ancient soil fertilizing practices by respective stable isotope and biomarker analyses. Prehistoric arable topsoils were preserved in archaeological pit fillings, whereas adjacent subsoils served as controls. One Early Weichselian humic zone represented the soil status before the introduction of agriculture. Recent topsoils served as an additional reference. The applied multi-proxy approach comprised total P and micronutrient contents, stable N isotope ratios, amino acid, steroid, and black carbon analyses as well as soil color measurements. Total contents of P and selected micronutrients (I, Cu, Mn, Mo, Se, Zn) of the arable soil relicts were above the limits for which nutrient deficiencies could be assumed. All pit fillings exhibited elevated δ15N values close to those of recent topsoils (δ15N>6 to 7‰), giving first hints for prehistoric organic N-input. Ancient legume cultivation as a potential source for N input could not be verified by means of amino acid analysis. In contrast, bile acids as markers for faecal input exhibited larger concentrations in the pit fillings compared with the reference and control soils indicating faeces (i.e. manure) input to Neolithic arable topsoils. Also black carbon contents were elevated, amounting up to 38% of soil organic carbon, therewith explaining the dark soil color in the pit fillings and pointing to inputs of burned biomass. The combination of different geochemical analyses revealed a sufficient nutrient status of prehistoric arable soils, as well as signs of amelioration (inputs of organic material like charcoal and faeces-containing manure). PMID:25180911

Late-Holocene climate and environmental change on the Antarctic Peninsula: multi-proxy palaeoclimate records from frozen moss banks

NASA Astrophysics Data System (ADS)

Roland, T.; Amesbury, M.; Royles, J.; Hodgson, D.; Convey, P.; Griffiths, H.; Charman, D.

2017-12-01

The Antarctic Peninsula (AP) has been one of the most rapidly warming regions on Earth, with air temperature increases of 3°C recorded since the mid-20th century. However, instrumental climate records are mostly limited to the late 1950s onwards and existing palaeoenvironmental data that provide a longer-term context to recent climate and biological changes are often spatially isolated and temporally fragmented. Ice-core records from the AP are not suitably located to be able to examine the spatial signature of climate changes over time. Moss banks located along the western AP are ideal archives for palaeoclimate research as they are well-preserved, have sufficiently high accumulation rates to permit decadally resolved analyses using multiple proxies over the last c. 4000 years, and are easily dated with 14C and 210Pb. Potential climate proxies (moss accumulation and growth rates, Δ13C in moss cellulose, testate amoebae concentration) are sensitive to regional temperature change, moderated by water availability and surface microclimate. Here we present multi-proxy records of biological change from these archives of late Holocene climate variability. We identified significant changepoints in six cores at three sites, across a transect spanning c. 600 km, observing that biological response to recent rapid warming on the AP is pervasive and unprecedented over the last 150 years. Longer records show that recent change is also unusual in the context of the past 4000 years and suggest that westerly wind strength linked to the Southern Annular Mode is the most likely driver of centennial-scale AP temperature variability. Widespread changes in the terrestrial biosphere of the AP in response to past temperature suggest that terrestrial ecosystems will alter rapidly under future warming scenarios, leading to major changes in the biology and landscape of this iconic region — an Antarctic greening to parallel well-established observations in the Arctic.

Climatic interpretation of the length fluctuations of Glaciar Frías, North Patagonia, Argentina

NASA Astrophysics Data System (ADS)

Leclercq, P. W.; Pitte, P.; Giesen, R. H.; Masiokas, M. H.; Oerlemans, J.

2011-10-01

We explore the climatic information contained in the record of length fluctuations of Glaciar Frías, in the North Patagonian Andes of Argentina. This record is one of the longest and most detailed glacier records in southern South America, starting in 1639. In order to interpret the length variations of Glaciar Frías since the maximum Little Ice Age extent in 1639, we use a combination of a simplified surface energy-balance model to calculate the glacier mass balance, and a flow-line model to account for the dynamical response of the glacier to changes in the climatic forcing. The overall retreat of the glacier observed over 1639-2009 is best explained by an annual mean temperature increase of 1.16 °C or a decrease in annual precipitation of 34%, most of which would have occurred during the 20th century. The glacier model is also forced with independent proxy-based reconstructions of precipitation and temperature, based on tree rings and a composition of documentary evidence, tree rings, sediments, corals, and ice cores. The uncertainties in the presently available proxy reconstructions are rather large, leading to a wide range in the modelled glacier length. Most of the observations lie within this range. However, in these reconstructions, the mid-17th century is too cold and the early 19th century ca. 0.7 °C too warm to explain the observed glacier lengths.

Reconstructing palaeo-environmental conditions in the Baltic: A multi-proxy comparison from IODP Site M0059 (Little Belt)

NASA Astrophysics Data System (ADS)

Kotthoff, Ulrich; Andrén, Thomas; Bauersachs, Thorsten; Fanget, Anne-Sophie; Granoszewski, Wojciech; Groeneveld, Jeroen; Krupinski, Nadine; Peyron, Odile; Stepanova, Anna; Cotterill, Carol

2015-04-01

Some of the largest marine environmental impacts from ongoing global climate change are occurring in continental shelf seas and enclosed basins, including severe oxygen depletion, intensifying stratification, and increasing temperatures. In order to predict future changes in water mass conditions, it is essential to reconstruct how these conditions have changed in the past. The brackish Baltic Sea is one of the largest semi-enclosed basins worldwide, and hence provides a unique opportunity to analyse past changes. IODP Expedition 347 recovered a unique set of long sediment cores from the Baltic Sea Basin which allow new high-resolution reconstructions. The application of existing and development of new proxies in such a setting is complicated, as environmental changes often occur on much faster time scales with much larger variations. Therefore, we present a comparison of commonly used proxies to reconstruct palaeoecosystems, -temperatures, and -salinity from IODP Site M0059 in the Little Belt. The age model for Site M0059 is based on 14C dating and biostratigraphic correlation with neighbouring terrestrial pollen records. The aim of our study is to reconstruct the development of the terrestrial and marine ecosystems in the research area and the related environmental conditions, and to identify potential limitations for specific proxies. Pollen is used as proxy for vegetation development in the hinterland of the southern Baltic Sea and as land/air-temperature proxies. By comparison with dinoflagellate cysts and green algae remains from the same samples, a direct land-sea comparison is provided. The application of the modern analogues technique to pollen assemblages has previously yielded precise results for late Pleistocene and Holocene datasets including specific information on seasonality, but pollen-based reconstructions for Northern Europe may be hampered by plant migration effects. Chironomid remains are used where possible as indicators for surface water conditions during the warm season. Analyses of palynomorphs and chironomids are complemented with the analysis of lipid palaeothermometers, such as TEX86 and the long chain diol index (LDI), which both allow reconstructing variation in sea surface temperatures (SST) of the Baltic Sea. In addition, the MBT/CBT proxy is used to infer past changes in mean annual air temperatures (MAAT) and the diol index (DI) to determine variation in salinity of the Baltic Sea's surface waters over the investigated time period. The low salinity (25 psu) of the Little Belt is a potential limitation for several of the used proxies, which could lead to under-estimation of paleo-temperatures. To quantitatively and qualitatively estimate the impact of salinity, δ18O measurements (monospecific) and faunal assemblage analyses are performed on benthic foraminifera as well as ostracod faunal assemblages, which are especially sensitive to bottom water salinity changes. The results of this inter-comparison study will be useful for the reconstruction of gradients between different settings, e.g. how water column stratification developed, possibly if and how changes in seasonality occurred, and to identify the circumstances under which specific proxies may be affected by secondary impacts.

Multiple oscillations during the Lateglacial as recorded in a multi-proxy, high-resolution record of the Moervaart palaeolake (NW Belgium)

NASA Astrophysics Data System (ADS)

Bos, Johanna A. A.; De Smedt, Philippe; Demiddele, Hendrik; Hoek, Wim Z.; Langohr, Roger; Marcelino, Vera; Van Asch, Nelleke; Van Damme, Dirk; Van der Meeren, Thijs; Verniers, Jacques; Boeckx, Pascal; Boudin, Mathieu; Court-Picon, Mona; Finke, Peter; Gelorini, Vanessa; Gobert, Stefan; Heiri, Oliver; Martens, Koen; Mostaert, Frank; Serbruyns, Lynn; Van Strydonck, Mark; Crombé, Philippe

2017-04-01

This paper presents the results of multi-disciplinary research carried out on the deposits of Moervaart depression, NW Belgium, one of the largest palaeolakes (∼25 km2) that existed during the Lateglacial interstadial in NW Europe. The multi-proxy study, including physical (organic matter and calcium carbonate, magnetic susceptibility, micromorphological), botanical (pollen, macrofossils, diatoms), zoological (ostracods, molluscs, chironomids) and chemical analyses (stable carbon and oxygen isotopes) has resulted in a detailed reconstruction of the Lateglacial landscape as well of the local conditions that prevailed in the lake itself. A chronology of the record was provided by radiocarbon dating and comparison with radiocarbon dates of the nearby Rieme site. These yielded a good match with the regional biostratigraphy. During the Lateglacial, vegetation and geomorphology of the landscape in general changed from a tundra landscape to a boreal forest. The vegetation development, however, was interrupted by a number of cold reversals. Three centennial-scale cold oscillations are present in the record: 1) the so-called Older Dryas corresponding to GI-1d in the Greenland ice-cores, 2) a short and pronounced cold event during the early Allerød, which could be correlated to GI-1c2 and 3) a cooling event during the late Allerød probably corresponding to the Intra Allerød Cold Period (IACP) or GI-1b. The latter most likely was responsible for the disappearance of the Moervaart palaeolake.

Multi-Season Regional Analysis of Multi-Species Occupancy: Implications for Bird Conservation in Agricultural Lands in East-Central Argentina

PubMed Central

Goijman, Andrea Paula; Conroy, Michael. J.; Bernardos, Jaime Nicolás; Zaccagnini, María Elena

2015-01-01

Rapid expansion and intensification of agriculture create challenges for the conservation of biodiversity and associated ecosystem services. In Argentina, the total row crop planted area has increased in recent decades with the expansion of soybean cultivation, homogenizing the landscape. In 2003 we started the first long-term, large-scale bird monitoring program in agroecosystems of central Argentina, in portions of the Pampas and Espinal ecoregions. Using data from this program, we evaluated the effect of land use and cover extent on birds between 2003-2012, accounting for imperfect detection probabilities using a Bayesian hierarchical, multi-species and multi-season occupancy model. We tested predictions that species diversity is positively related to habitat heterogeneity, which in intensified agroecosystems is thought to be mediated by food availability; thus the extent of land use and cover is predicted to affect foraging guilds differently. We also infer about ecosystem services provisioning and inform management recommendations for conservation of birds. Overall our results support the predictions. Although many species within each guild responded differently to land use and native forest cover, we identified generalities for most trophic guilds. For example, granivorous gleaners, ground insectivores and omnivores responded negatively to high proportions of soybean, while insectivore gleaners and aerial foragers seemed more tolerant. Habitat heterogeneity would likely benefit most species in an intensified agroecosystem, and can be achieved with a diversity of crops, pastures, and natural areas within the landscape. Although most studied species are insectivores, potentially beneficial for pest control, some guilds such as ground insectivores are poorly represented, suggesting that agricultural intensification reduces ecological functions, which may be recovered through management. Continuation of the bird monitoring program will allow us to continue to inform for conservation of birds in agroecosystems, identify research needed to reduce key uncertainties, and anticipate the effects of changes in agriculture in central Argentina. PMID:26086250

Show me the data: advances in multi-model benchmarking, assimilation, and forecasting

NASA Astrophysics Data System (ADS)

Dietze, M.; Raiho, A.; Fer, I.; Cowdery, E.; Kooper, R.; Kelly, R.; Shiklomanov, A. N.; Desai, A. R.; Simkins, J.; Gardella, A.; Serbin, S.

2016-12-01

Researchers want their data to inform carbon cycle predictions, but there are considerable bottlenecks between data collection and the use of data to calibrate and validate earth system models and inform predictions. This talk highlights recent advancements in the PEcAn project aimed at it making it easier for individual researchers to confront models with their own data: (1) The development of an easily extensible site-scale benchmarking system aimed at ensuring that models capture process rather than just reproducing pattern; (2) Efficient emulator-based Bayesian parameter data assimilation to constrain model parameters; (3) A novel, generalized approach to ensemble data assimilation to estimate carbon pools and fluxes and quantify process error; (4) automated processing and downscaling of CMIP climate scenarios to support forecasts that include driver uncertainty; (5) a large expansion in the number of models supported, with new tools for conducting multi-model and multi-site analyses; and (6) a network-based architecture that allows analyses to be shared with model developers and other collaborators. Application of these methods is illustrated with data across a wide range of time scales, from eddy-covariance to forest inventories to tree rings to paleoecological pollen proxies.

Extreme wave deposits on the Pacific coast of Mexico: Tsunamis or storms? — A multi-proxy approach

NASA Astrophysics Data System (ADS)

Ramírez-Herrera, María-Teresa; Lagos, Marcelo; Hutchinson, Ian; Kostoglodov, Vladimir; Machain, Maria Luisa; Caballero, Margarita; Goguitchaichvili, Avto; Aguilar, Bertha; Chagué-Goff, Catherine; Goff, James; Ruiz-Fernández, Ana-Carolina; Ortiz, Modesto; Nava, Hector; Bautista, Francisco; Lopez, Gloria I.; Quintana, Patricia

2012-02-01

Historical and instrumental data show that the Pacific coast of Mexico has been exposed to destructive tsunamis over at least the past 500 years. This coast is also affected by hurricanes generated in the eastern Pacific. The great 1985 Mexico earthquake and its aftershock generated tsunamis that affected the Ixtapa-Zihuatanejo and Michoacán coast. The purpose of our study was two-fold — a) to determine whether storm and tsunami deposits could be distinguished, and b) whether tsunami deposits from historical events are preserved in the tropical environments of the Ixtapa-Zihuatanejo coast. Two anomalous sand units in the Ixtapa estuary are interpreted to be the result of high-energy marine inundation events that occurred in the last century. Several lines of evidence using a multi-proxy approach (historical studies, interviews with local witnesses, geomorphological and geological surveys, coring and trenching, laboratory analyses including grain size, micropaleontology, geochemistry, magnetic susceptibility and radiometric dating, and numerical modeling) indicate the occurrence of two tsunamis that we link to local events: the 21st September 1985 Mexico and possibly the 14th March 1979 Petatlan earthquakes. We thereby provide the first onshore geological evidence of historical tsunamis on the Pacific coast of Mexico.

Synchronous multi-decadal climate variability of the whole Pacific areas revealed in tree rings since 1567

NASA Astrophysics Data System (ADS)

Fang, Keyan; Cook, Edward; Guo, Zhengtang; Chen, Deliang; Ou, Tinghai; Zhao, Yan

2018-02-01

Oceanic and atmospheric patterns play a crucial role in modulating climate variability from interannual to multi-decadal timescales by causing large-scale co-varying climate changes. The brevity of the existing instrumental records hinders the ability to recognize climate patterns before the industrial era, which can be alleviated using proxies. Unfortunately, proxy based reconstructions of oceanic and atmospheric modes of the past millennia often have modest agreements with each other before the instrumental period, raising questions about the robustness of the reconstructions. To ensure the stability of climate signals in proxy data through time, we first identified tree-ring datasets from distant regions containing coherent variations in Asia and North America, and then interpreted their climate information. We found that the multi-decadal covarying climate patterns of the middle and high latitudinal regions around the northern Pacific Ocean agreed quite well with the climate reconstructions of the tropical and southern Pacific areas. This indicates a synchronous variability at the multi-decadal timescale of the past 430 years for the entire Pacific Ocean. This pattern is closely linked to the dominant mode of the Pacific sea surface temperature (SST) after removing the warming trend. This Pacific multi-decadal SST variability resembles the Interdecadal Pacific Oscillation.

Methods to Assess the Utility of Proxies

DTIC Science & Technology

1990-08-01

PROXIES Gottfredson [5 has reviewed ways to analyze potential proxies for the National Academy of Science committee that oversees the work of the...distribution might get the highest possible scores on the test. Together, the Gottfredson and Allred papers suggest that different analyses are required...summarizes the implications of the Gottfredson and Allred papers. These two papers suggest that different kinds of analyses should be done, depending

Indian Summer Monsoon dynamics during Termination II and MIS 5e

NASA Astrophysics Data System (ADS)

Magiera, Matthias; Erhardt, Andrea M.; Hartland, Adam; Kwiecien, Ola; Cheng, Hai; Immenhauser, Adrian; Turchyn, Alexandra; Breitenbach, Sebastian F. M.

2017-04-01

The interpretation of speleothem oxygen isotope ratios (δ18O) as proxy for Indian Summer Monsoon (ISM) dynamics is ambiguous, due to multiple influencing factors. Here we combine δ18O and calcium isotope δ44Ca analyses with elemental data to delineate regional shifts in moisture source, local rainfall amount, and changes in ISM intensity and length during Termination II and MIS 5e. Oxygen isotope ratios reflect a mixed signal of moisture source dynamics and rainfall amount; δ44Ca and Mg/Ca ratios are interpreted as proxies for local effective moisture and prior calcite precipitation (PCP) in the epikarst. The age of stalagmite MAW-3 from Mawmluh Cave, NE India, is constraint by six U-series dates. 108 samples, obtained at 0.4 mm resolution from the 70 mm long speleothem sample, have been analysed for δ18O, δ44Ca and Mg/Ca. Oxygen isotope ratios were measured on a ThermoFisher Scientific MAT 253 at Ruhr-University Bochum. Elemental ratios were measured on a quadrupole ICP-MS at Waikato University. Calcium isotope ratios were analyzed on a ThermoFisher Scientific Triton at University of Cambridge. MAW-3 grew from 136 kyrs BP to 96 kyrs BP, covering Termination II and MIS 5e. Oxygen isotope values are high (ca. +0.91 ‰) during Termination II, reach a minimum during MIS 5e (-3.5 ‰), and rise again to -0.2 ‰ at the end of MIS 5e. Calcium isotope ratios range from -0.32 ‰ to -0.70 ‰ and show a positive correlation (R2= 0.7) with δ18O. High δ18O values during Termination II reflect reduced atmospheric circulation and/or a proximal moisture source (Bay of Bengal), implying lowered ISM intensity. A positive correlation of δ18O with δ44Ca suggests concurrent changes of moisture source location and local rainfall amount, with a proximal moisture source and reduced effective rainfall during periods of weak ISM. Elevated Mg/Ca ratios at such intervals corroborate PCP occurrence, which reflects dry conditions. The beginning of MIS 5e (ca. 132 kyrs BP) is marked by a rapid change to lower δ18O and δ44Ca, suggesting increased local infiltration with increasing ISM rainfall, and a concurrent change to a more distal moisture source. The MAW-3 multi-proxy record compares well with reconstructions from China and northern India, the latter being more depleted, due to Rayleigh fractionation. We suggest that multi-proxy analyses of δ18O, δ44Ca and Mg/Ca greatly help to delineate regional circulation pattern and local effective moisture dynamics in monsoonal settings.

Alpine Holocene Tree Ring Isotope Records - A Synthesis of a Multi-Proxy Approach in Dendroclimatology

NASA Astrophysics Data System (ADS)

Ziehmer, Malin Michelle; Nicolussi, Kurt; Schlüchter, Christian; Leuenberger, Markus

2017-04-01

High-resolution climate reconstructions based on tree-ring proxies are often limited by the individual segment length of living trees selected at the defined sampling sites, which mostly results in relatively short multi-centennial proxy series. A potential extension of living wood records comprise the addition of subfossil and archeological wood remains resulting in chronologies and associated climate reconstructions which are able to cover a few millennia in central Europe (e.g. Büntgen et al., 2011). However, existing multi-millennial tree-ring width chronologies in central Europe rank among the longest continuous chronologies world-wide and span the entire Holocene (Becker et al., 1993; Nicolussi et al. 2009). So far, these chronologies have mainly been used for dating subfossil wood samples, floating chronologies and archeological artifacts, but only in parts for reconstructing climate. Finds of Holocene wood remains in glacier forefields, peat bogs and small lakes allow us not only to establish such long-term tree-ring width records; further they offer the possibility to establish multi-millennial proxy records for the entire Holocene by using a multi-proxy approach which includes both tree-ring width and triple stable isotope ratios. As temperature limits tree growth at the Alpine upper tree line, the existing tree-ring width records are currently limited to reconstruct a single environmental variable. In the framework of the project Alpine Holocene Tree Ring Isotope Records, we combine tree-ring width, cellulose content as well as carbon, oxygen and hydrogen isotope series in a multi-proxy approach which allows the reconstruction of past environments by combining both Holocene wood remains and recent tree samples from two Alpine tree-line species. For this purpose, α-cellulose is prepared from 5-year tree ring blocks following the procedure after Boettger et al. (2007) and subsequently crushed by ultrasonic homogenization (Laumer et al., 2009). The cellulose content is determined for each individual sample and carbon, oxygen and hydrogen isotopic ratios are measured simultaneously (Loader et al., 2015). The isotope records of carbon, oxygen and hydrogen show distinct low-frequency trends for the Early- and Mid-Holocene, but the individual series per proxy are often offset in their isotopic signature. As the sampling sites in our study are distributed along a SW-NE transect, the influence of the site conditions (latitude, longitude, elevation, exposition) and the tree species is tested and subsequently a correction is applied to the individual series. In addition, the tree-ring width records operate as a helpful tool in detecting and attributing the influence of larch budmoth outbreaks on the cellulose content and isotope records. We here present a synthesis of the applied multi-proxy approach and its ability to reconstruct Holocene climate variability for the time span from 9000 to 3500 years b2k covering the Early-Holocene (9000 to 7200 years b2k) and Mid-Holocene (7200 to 4200 years b2k) and the transition to the late Holocene (4200 to 3500 years b2k) as well as the recent 400 years including the modern warming. References Becker, B., & Kromer, B. Palaeogeogr. Palaeoclimatol. Palaeoecol., 1993, 103(1): 67-71 Boettger, T., et al. Anal. Chem., 2007, 79: 4603-4612 Büntgen, U. et al. Science, 2011, 331(6017): 578-582 Laumer, W., et al. Rapid Commun. Mass Spectrom., 2009, 23: 1934-1940 Loader, N.J., et al. Anal. Chem., 2015, 87: 376-380 Nicolussi K., et al. The Holocene, 2009, 19(6): 909-920

Multi Proxy Observations of Changes in the Late Holocene Paleoenvironment of a South East Texas Reverse Estuary

NASA Astrophysics Data System (ADS)

Mckay, M.

2016-12-01

Baffin Bay is a Reverse estuary located in the semi-arid south Texas coastal plain. It receives on average 60-80 cm of precipitation per year with evaporation exceeding precipitation by 60 cm/year. It has experienced a variety of paleoenvironmental influences since its formation as sea levels rose during the Holocene period. Many of these environmental influences include some terrestrial deposits from creeks, and changes in precipitation patterns. One of the most significant influences on the bay was when it was separated from the Gulf of Mexico by the formation of a large Barrier Island (Padre Island) 5,500 years ago. In recent times, Baffin Bay has experienced decreases in water quality. While it is evident that current anthropological inputs (increased nutrient loading, etc.) are contributory, natural factors that include long-term changes in precipitation patterns, and fresh water flows, along with changes in the bays circulation patterns may also influence the functioning of the bay. In this study, short sediment cores ( 1.3-1.7 m) were taken from twelve locations around the main basin and tributaries of the bay. All cores were sampled at either one or five centimetre intervals depending on the technique employed, using several non-destructive and destructive proxy techniques. Chronological control was provided by Cs-137/Pb-210 analyses. Proxy analysis has corresponded well with both with known events and with the assistance of Cs-137/Pb-210 analyses, are able help discern environmental inputs that are of anthropological origin as opposed to those that of a natural origin or cycle.

A High-Resolution Record of Warm Water Inflow and Iceberg Calving in Upernavik Isfjord During the Past 150 Years.

NASA Astrophysics Data System (ADS)

Vermassen, F.; Andresen, C. S.; Sabine, S.; Holtvoeth, J.; Cordua, A. E.; Wangner, D. J.; Dyke, L. M.; Kjaer, K. H.; Kokfelt, U.; Haubner, K.

2016-12-01

There is a growing body of evidence demonstrating that changes in warm water inflow to Greenlandic fjords are linked to the rapid retreat of marine-terminating outlet glaciers. This process is thought to be responsible for a substantial component of the increased mass loss from the Greenland Ice Sheet over the last two decades. Sediment cores from glaciated fjords provide high-resolution sedimentological and biological proxy records which can be used to evaluate the interplay of warm water inflow and glacier calving over recent time scales. In this study, multiple short cores ( 2 m) from Upernavik Isfjord, West Greenland, were analysed to establish a multi-proxy record of glacier behaviour and oceanographic conditions that spans the past 150 years. The down-core variation in the amount of ice-rafted debris reveals periods of increased glacier calving, and biomarker proxies are used to reconstruct variability in the inflow of warm, Atlantic-sourced water to the fjord. Measurements of the sortable silt grain size are used to reconstruct bottom-current strength; periods of vigorous current flow are assumed to be due to enhanced warm water inflow. Finally, a record of glacier terminus position changes, derived from historical observations and satellite imagery, allows comparison of our new proxy records with the retreat of the ice margin from 1849 onwards. We use these data to assess the relative importance of mechanisms controlling the (rapid) retreat of marine-terminating glaciers in Upernavik Isfjord.

Rights questioned. Limitations of poverty-reduction policies in Argentina.

PubMed

Faur, Eleonor; Campos, Luis; Pautassi, Laura; Zimerman, Silvina

2009-01-01

This article analyses, from a human rights' approach, a group of social programmes implemented in Argentina from the year 2002, at the time of the biggest socioeconomic crisis that the country has suffered in the last decades. The main characteristics of the programmes are reviewed, and their anti-poverty strategy, along with design and implementation, are evaluated in relation to human rights. An assessment is also made of the existence of mechanisms for citizens to present claims. Finally, a set of recommendations are made to facilitate the adaptation of the programmes analysed to the duties the State of Argentina has as result of its adherence to international laws on human rights. The analytical methodology proposed by this article could be applied to other policy areas.

Assesment of publication practices in geosciences in developing countries

NASA Astrophysics Data System (ADS)

Cazenave, A.; Barbe, V.

2003-12-01

We present results of a study which goal was to investigate in which journals scientists in geosciences (i.e., in the fields covered by the AGU) in developing countries publish most of their papers.We were interested in particular in looking at the percentage of publications in AGU journals. Using science indicators collected by the Institute for Scientific Information (ISI), we analysed publication practices for 1997-2002 in the following countries : India, China, Russia, Brazil, Argentina and Chile. We investigated the evolution of the number of publications through time, identified most used journals, determined times cited and impact factors of papers published in the top 15 most used journals. We also determined the percentage of articles published in AGU journals versus other journals. We found that for the 6 counties considered, this percentage varies from about 2 to 3 percent (Argentina, China) to about 8 percent (the other 4 countries). Investigation of authors addresses indicates that the majority of articles published in AGU journals are multi-countries publications, involving international collaboration mainly with scientists from North America and Europe. Implications on page-charge and access to AGU journals are also discussed.

Preboreal climate oscillations in Europe: Wiggle-match dating and synthesis of Dutch high-resolution multi-proxy records

NASA Astrophysics Data System (ADS)

Bos, Johanna A. A.; van Geel, Bas; van der Plicht, Johannes; Bohncke, Sjoerd J. P.

2007-08-01

In order to compare environmental and inferred climatic change during the Preboreal in The Netherlands, five terrestrial records were analysed. Detailed multi-proxy analyses including microfossils (e.g., pollen, spores, algae, and fungal spores), macroremains (e.g., seeds, fruits, wood, mosses, etc.), and loss on ignition measurements were carried out with high temporal resolution. To link the five Preboreal records, accurate chronologies were produced by AMS 14C wiggle-match dating. The Dutch records show that following the Lateglacial/Holocene climate warming, birch woodlands expanded between 11,530 and 11,500 cal BP during the Friesland Phase of the Preboreal. After the Friesland Phase, two distinct climatic shifts could be inferred: (1) around 11,430-11,350 cal BP the expansion of birch forests was interrupted by a dry continental phase with open grassland vegetation, the Rammelbeek Phase. This phase was coeval with the coldest part of the Preboreal oscillation (PBO) as observed in the δ 18O record of the Greenland ice-core records and has been attributed to a large meltwater flux that resulted in a temporary decrease of the thermohaline circulation in the North Atlantic. (2) At the start of the Late Preboreal, between 11,270 and 11,210 cal BP, a sudden shift to a more humid climate occurred and birch forests expanded again. A simultaneous increase in the cosmogenic nuclides 14C and 10Be suggests that these changes in climate and vegetation were forced by a sudden decline in solar activity. Expansion of pine occurred during the later part of the Late Preboreal. At the onset of the Boreal, between 10,770 and 10,700 cal BP, dense woodlands with hazel, oak, elm and pine started to develop in The Netherlands.

Columnar jointing in vapor-phase-altered, non-welded Cerro Galán Ignimbrite, Paycuqui, Argentina

USGS Publications Warehouse

Wright, Heather M.; Lesti, Chiara; Cas, Ray A.F.; Porreca, Massimiliano; Viramonte, Jose G.; Folkes, Christopher B.; Giordano, Guido

2011-01-01

Columnar jointing is thought to occur primarily in lavas and welded pyroclastic flow deposits. However, the non-welded Cerro Galán Ignimbrite at Paycuqui, Argentina, contains well-developed columnar joints that are instead due to high-temperature vapor-phase alteration of the deposit, where devitrification and vapor-phase crystallization have increased the density and cohesion of the upper half of the section. Thermal remanent magnetization analyses of entrained lithic clasts indicate high emplacement temperatures, above 630°C, but the lack of welding textures indicates temperatures below the glass transition temperature. In order to remain below the glass transition at 630°C, the minimum cooling rate prior to deposition was 3.0 × 10−3–8.5 × 10−2°C/min (depending on the experimental data used for comparison). Alternatively, if the deposit was emplaced above the glass transition temperature, conductive cooling alone was insufficient to prevent welding. Crack patterns (average, 4.5 sides to each polygon) and column diameters (average, 75 cm) are consistent with relatively rapid cooling, where advective heat loss due to vapor fluxing increases cooling over simple conductive heat transfer. The presence of regularly spaced, complex radiating joint patterns is consistent with fumarolic gas rise, where volatiles originated in the valley-confined drainage system below. Joint spacing is a proxy for cooling rates and is controlled by depositional thickness/valley width. We suggest that the formation of joints in high-temperature, non-welded deposits is aided by the presence of underlying external water, where vapor transfer causes crystallization in pore spaces, densifies the deposit, and helps prevent welding.

Dengue Virus 1 Outbreak in Buenos Aires, Argentina, 2016.

PubMed

Tittarelli, Estefanía; Lusso, Silvina B; Goya, Stephanie; Rojo, Gabriel L; Natale, Mónica I; Viegas, Mariana; Mistchenko, Alicia S; Valinotto, Laura E

2017-10-01

The largest outbreak of dengue in Buenos Aires, Argentina, occurred during 2016. Phylogenetic, phylodynamic, and phylogeographic analyses of 82 samples from dengue patients revealed co-circulation of 2 genotype V dengue virus lineages, suggesting that this virus has become endemic to the Buenos Aires metropolitan area.

Luminescence signal profiling: a new proxy for sedimentologically "invisible" marine Mass Transport Deposits (MTDs)

NASA Astrophysics Data System (ADS)

López, Gloria I.; Bialik, Or; Waldmann, Nicolas

2017-04-01

When dealing with fine-grained, organic-rich, colour-monotone, underwater marine sediment cores retrieved from the continental shelf or slope, the initial visual impression, upon split-opening the vessels, is often of a "disappointing" homogeneous, monotonous, continuous archive. Only after thorough, micro- to macro-scale, multi-parameter investigations the sediment reveals its treasures, initially by performing some measurements on the intact core itself, hence depicting for the first time its contents, and subsequently by carrying out the destructive, multi-proxy sample-based analyses. Usually, routine Multi-Sensor Core Logger (MSCL) measurements of petrophysical parameters (e.g. magnetic susceptibility, density, P-Wave velocity) on un-split sediment cores are the first undertaken while still on-board in the field or back at the laboratory. Less often done, but equally valuable, are continuous X-Ray and CT scan imaging of the same intact archives. Upon splitting, routine granulometry, micro- and macro-fossil and invertebrate identification, total organic / inorganic carbon content (TOC / TIC), amid other analyses take place. The geochronology component is also established usually by AMS 14C on selected organic-rich units, and less common is Optically Stimulated Luminescence (OSL) dating used on the coarser-grained, siliciclastic layers. A relatively new tool used in Luminescence, the Portable OSL Reader, employed to rapidly assess the luminescence signal of untreated poly-mineral samples to assist with targeted field sampling for full OSL dating, was used for the first time in marine sediment cores as a novel petrophysical characterization tool with astonishing results. In this study, two 2 m-long underwater piston sediment cores recovered from 200 m depths on the continental shelf off-southern Israel, were subjected to pulsed-photon stimulation (PPSL) obtaining favourable luminescence signals along their entire lengths. Astoundingly, luminescence signals were obtained on both, already split-opened cores. Both cores depicted the monotonous characteristics of homogeneousness down-core as per most of the results obtained from the non-destructive and destructive tests. One of the cores showed several small higher energy events, including a Mass Transport Deposit (MTD) within its first 10 cm, only fully visible on the CT scan imaging, the PPSL profile and particle size distribution plot. This initial investigation demonstrates the feasibility and usefulness of luminescence profiling as a new sedimentological and petrophysical proxy to better visualize homogeneous yet complex, fine-grained, underwater archives. Moreover, it helps to understand the continuity of the stratigraphy and linearity of deposition of the sediment, besides assisting on the estimation of relative ages provided that good OSL ages are obtained throughout the recovered archive.

Improved spectral comparisons of paleoclimate models and observations via proxy system modeling: Implications for multi-decadal variability

NASA Astrophysics Data System (ADS)

Dee, S. G.; Parsons, L. A.; Loope, G. R.; Overpeck, J. T.; Ault, T. R.; Emile-Geay, J.

2017-10-01

The spectral characteristics of paleoclimate observations spanning the last millennium suggest the presence of significant low-frequency (multi-decadal to centennial scale) variability in the climate system. Since this low-frequency climate variability is critical for climate predictions on societally-relevant scales, it is essential to establish whether General Circulation models (GCMs) are able to simulate it faithfully. Recent studies find large discrepancies between models and paleoclimate data at low frequencies, prompting concerns surrounding the ability of GCMs to predict long-term, high-magnitude variability under greenhouse forcing (Laepple and Huybers, 2014a, 2014b). However, efforts to ground climate model simulations directly in paleoclimate observations are impeded by fundamental differences between models and the proxy data: proxy systems often record a multivariate and/or nonlinear response to climate, precluding a direct comparison to GCM output. In this paper we bridge this gap via a forward proxy modeling approach, coupled to an isotope-enabled GCM. This allows us to disentangle the various contributions to signals embedded in ice cores, speleothem calcite, coral aragonite, tree-ring width, and tree-ring cellulose. The paper addresses the following questions: (1) do forward-modeled ;pseudoproxies; exhibit variability comparable to proxy data? (2) if not, which processes alter the shape of the spectrum of simulated climate variability, and are these processes broadly distinguishable from climate? We apply our method to representative case studies, and broaden these insights with an analysis of the PAGES2k database (PAGES2K Consortium, 2013). We find that current proxy system models (PSMs) can help resolve model-data discrepancies on interannual to decadal timescales, but cannot account for the mismatch in variance on multi-decadal to centennial timescales. We conclude that, specific to this set of PSMs and isotope-enabled model, the paleoclimate record may exhibit larger low-frequency variability than GCMs currently simulate, indicative of incomplete physics and/or forcings.

The Military As A Hindrance In Mexico’s Consolidation Of Democracy

DTIC Science & Technology

2001-12-01

superficially compared to those of other Latin American countries such as Argentina, Brazil, and Chile . This academic neglect by U.S. scholars may also be...analyses the pre and post civil-military relations of Argentina, Brazil, Chile , Peru, and Uruguay. 4. Limiting Prerogatives Similar to Stepan’s...

Rewriting Citizenship? Civic Education in Costa Rica and Argentina

ERIC Educational Resources Information Center

Suarez, David F.

2008-01-01

To what degree are nations "rewriting" citizenship by expanding discussions of human rights, diversity and cultural pluralism in modern civic education, and what explains variation between countries? This study addresses these issues by analysing the intended content of civic education in Costa Rica and Argentina. Over time, civic…

The impact of modern migrations on present-day multi-ethnic Argentina as recorded on the mitochondrial DNA genome.

PubMed

Catelli, María Laura; Alvarez-Iglesias, Vanesa; Gómez-Carballa, Alberto; Mosquera-Miguel, Ana; Romanini, Carola; Borosky, Alicia; Amigo, Jorge; Carracedo, Angel; Vullo, Carlos; Salas, Antonio

2011-08-30

The genetic background of Argentineans is a mosaic of different continental ancestries. From colonial to present times, the genetic contribution of Europeans and sub-Saharan Africans has superposed to or replaced the indigenous genetic 'stratum'. A sample of 384 individuals representing different Argentinean provinces was collected and genotyped for the first and the second mitochondrial DNA (mtDNA) hypervariable regions, and selectively genotyped for mtDNA SNPs. This data was analyzed together with additional 440 profiles from rural and urban populations plus 304 from Native American Argentineans, all available from the literature. A worldwide database was used for phylogeographic inferences, inter-population comparisons, and admixture analysis. Samples identified as belonging to hg (hg) H2a5 were sequenced for the entire mtDNA genome. Phylogenetic and admixture analyses indicate that only half of the Native American component in urban Argentineans might be attributed to the legacy of extinct ancestral Argentineans and that the Spanish genetic contribution is slightly higher than the Italian one. Entire H2a5 genomes linked these Argentinean mtDNAs to the Basque Country and improved the phylogeny of this Basque autochthonous clade. The fingerprint of African slaves in urban Argentinean mtDNAs was low and it can be phylogeographically attributed predominantly to western African. The European component is significantly more prevalent in the Buenos Aires province, the main gate of entrance for Atlantic immigration to Argentina, while the Native American component is larger in North and South Argentina. AMOVA, Principal Component Analysis and hgs/haplotype patterns in Argentina revealed an important level of genetic sub-structure in the country. Studies aimed to compare mtDNA frequency profiles from different Argentinean geographical regions (e.g., forensic and case-control studies) should take into account the important genetic heterogeneity of the country in order to prevent false positive claims of association in disease studies or inadequate evaluation of forensic evidence.

The impact of modern migrations on present-day multi-ethnic Argentina as recorded on the mitochondrial DNA genome

PubMed Central

2011-01-01

Background The genetic background of Argentineans is a mosaic of different continental ancestries. From colonial to present times, the genetic contribution of Europeans and sub-Saharan Africans has superposed to or replaced the indigenous genetic 'stratum'. A sample of 384 individuals representing different Argentinean provinces was collected and genotyped for the first and the second mitochondrial DNA (mtDNA) hypervariable regions, and selectively genotyped for mtDNA SNPs. This data was analyzed together with additional 440 profiles from rural and urban populations plus 304 from Native American Argentineans, all available from the literature. A worldwide database was used for phylogeographic inferences, inter-population comparisons, and admixture analysis. Samples identified as belonging to hg (hg) H2a5 were sequenced for the entire mtDNA genome. Results Phylogenetic and admixture analyses indicate that only half of the Native American component in urban Argentineans might be attributed to the legacy of extinct ancestral Argentineans and that the Spanish genetic contribution is slightly higher than the Italian one. Entire H2a5 genomes linked these Argentinean mtDNAs to the Basque Country and improved the phylogeny of this Basque autochthonous clade. The fingerprint of African slaves in urban Argentinean mtDNAs was low and it can be phylogeographically attributed predominantly to western African. The European component is significantly more prevalent in the Buenos Aires province, the main gate of entrance for Atlantic immigration to Argentina, while the Native American component is larger in North and South Argentina. AMOVA, Principal Component Analysis and hgs/haplotype patterns in Argentina revealed an important level of genetic sub-structure in the country. Conclusions Studies aimed to compare mtDNA frequency profiles from different Argentinean geographical regions (e.g., forensic and case-control studies) should take into account the important genetic heterogeneity of the country in order to prevent false positive claims of association in disease studies or inadequate evaluation of forensic evidence. PMID:21878127

Phylodynamics of vampire bat-transmitted rabies in Argentina

PubMed Central

DOHMEN, F. GURY; BELTRAN, F.; NOVARO, L.; RUSSO, S.; FREIRE, M. C.; VELASCO-VILLA, A.; MBAYED, V. A.; CISTERNA, D. M.

2016-01-01

Common vampire bat populations distributed from Mexico to Argentina are important rabies reservoir hosts in Latin America. The aim of this work was to analyse the population structure of the rabies virus (RABV) variants associated with vampire bats in the Americas and to study their phylodynamic pattern within Argentina. The phylogenetic analysis based on all available vampire bat-related N gene sequences showed both a geographical and a temporal structure. The two largest groups of RABV variants from Argentina were isolated from northwestern Argentina and from the central western zone of northeastern Argentina, corresponding to livestock areas with different climatic, topographic and biogeographical conditions, which determined their dissemination and evolutionary patterns. In addition, multiple introductions of the infection into Argentina, possibly from Brazil, were detected. The phylodynamic analysis suggests that RABV transmission dynamics is characterized by initial epizootic waves followed by local enzootic cycles with variable persistence. Anthropogenic interventions in the ecosystem should be assessed taking into account not only the environmental impact but also the potential risk of disease spreading through dissemination of current RABV lineages or the emergence of novel ones associated with vampire bats. PMID:24661865

Multiple Types of Memory and Everyday Functional Assessment in Older Adults

PubMed Central

Beaver, Jenna

2017-01-01

Abstract Objective Current proxy measures for assessing everyday functioning (e.g., questionnaires, performance-based measures, and direct observation) show discrepancies in their rating of functional status. The present study investigated the relationship between multiple proxy measures of functional status and content memory (i.e., memory for information), temporal order memory, and prospective memory in an older adult sample. Method A total of 197 community-dwelling older adults who did (n = 45) or did not meet (n = 152) criteria for mild cognitive impairment (MCI), completed six different assessments of functional status (two questionnaires, two performance-based tasks, and two direct observation tasks) as well as experimental measures of content memory, prospective memory, and temporal order memory. Results After controlling for demographics and content memory, the temporal order and prospective memory measures explained a significant amount of variance in all proxy functional status measures. When all variables were entered into the regression analyses, content memory and prospective memory were found to be significant predictors of all measures of functional status, whereas temporal order memory was a significant predictor for the questionnaire and direct observation measures, but not performance-based measures. Conclusion The results suggest that direct observation and questionnaire measures may be able to capture components of everyday functioning that require context and temporal sequencing abilities, such as multi-tasking, that are not as well captured in many current laboratory performance-based measures of functional status. Future research should aim to inform the development and use of maximally effective and valid proxy measures of functional ability. PMID:28334170

Multi-proxy experimental calibration in cold water corals for high resolution paleoreconstructions

NASA Astrophysics Data System (ADS)

Pelejero, C.; Martínez-Dios, A.; Ko, S.; Sherrell, R. M.; Kozdon, R.; López-Sanz, À.; Calvo, E.

2017-12-01

Cold-water corals (CWCs) display an almost cosmopolitan distribution over a wide range of depths. Similar to their tropical counterparts, they can provide continuous, high-resolution records of up to a century or more. Several CWC elemental and isotopic ratios have been suggested as useful proxies, but robust calibrations under controlled conditions in aquaria are needed. Whereas a few such calibrations have been performed for tropical corals, they are still pending for CWCs. This reflects the technical challenges involved in maintaining these slow-growing animals alive during the long-term experiments required to achieve sufficient skeletal growth for geochemical analyses. We will show details of the set up and initial stages of a long-term experiment being run at the ICM (Barcelona), where live specimens (>150) of Desmophyllum dianthus sampled in Comau Fjord (Chile) are kept under controlled and manipulated physical chemistry (temperature, pH, phosphate, barium, cadmium) and feeding conditions. With this set up, we aim to calibrate experimentally several specific elemental ratios including P/Ca, Ba/Ca, Cd/Ca, B/Ca, U/Ca and Mg/Li as proxies of nutrients dynamics, pH, carbonate ion concentration and temperature. For the trace element analysis, we are analyzing coral skeletons using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), running quantitative analyses on spot sizes of tens of microns, and comparing to micromilling and solution ICP-MS. Preliminary data obtained using these techniques will be presented, as well as measurements of calcification rate. Since coral-water corals are potentially vulnerable to ocean acidification, the same experiment is being exploited to assess potential effects of the pH stressor in D. dianthus; main findings to date will be summarized.

Munroa argentina, a Grass of the South American Transition Zone, Survived the Andean Uplift, Aridification and Glaciations of the Quaternary.

PubMed

Amarilla, Leonardo D; Anton, Ana M; Chiapella, Jorge O; Manifesto, María M; Angulo, Diego F; Sosa, Victoria

2015-01-01

The South American Transition Zone (SATZ) is a biogeographic area in which not only orogeny (Andes uplift) and climate events (aridification) since the mid-Miocene, but also Quaternary glaciation cycles had an important impact on the evolutionary history of the local flora. To study this effect, we selected Munroa argentina, an annual grass distributed in the biogeographic provinces of Puna, Prepuna and Monte. We collected 152 individuals from 20 localities throughout the species' range, ran genetic and demographic analyses, and applied ecological niche modeling. Phylogenetic and population genetic analyses based on cpDNA and AFLP data identified three phylogroups that correspond to the previously identified subregions within the SATZ. Molecular dating suggests that M. argentina has inhabited the SATZ since approximately 3.4 (4.2-1.2) Ma and paleomodels predict suitable climate in these areas during the Interglacial period and the Last Glacial Maximum. We conclude that the current distribution of M. argentina resulted from the fragmentation of its once continuous range and that climate oscillations promoted ecological differences that favored isolation by creating habitat discontinuity.

Microsatellite variation and genetic structuring in Mugil liza (Teleostei: Mugilidae) populations from Argentina and Brazil

NASA Astrophysics Data System (ADS)

Mai, Ana C. G.; Miño, Carolina I.; Marins, Luis F. F.; Monteiro-Neto, Cassiano; Miranda, Laura; Schwingel, Paulo R.; Lemos, Valéria M.; Gonzalez-Castro, Mariano; Castello, Jorge P.; Vieira, João P.

2014-08-01

The mullet Mugil liza is distributed along the Atlantic coast of South America, from Argentina to Venezuela, and it is heavily exploited in Brazil. We assessed patterns of distribution of neutral nuclear genetic variation in 250 samples from the Brazilian states of Rio de Janeiro, São Paulo, Santa Catarina and Rio Grande do Sul (latitudinal range of 23-31°S) and from Buenos Aires Province in Argentina (36°S). Nine microsatellite loci revealed 131 total alleles, 3-23 alleles per locus, He: 0.69 and Ho: 0.67. Significant genetic differentiation was observed between Rio de Janeiro samples (23°S) and those from all other locations, as indicated by FST, hierarchical analyses of genetic structure, Bayesian cluster analyses and assignment tests. The presence of two different demographic clusters better explains the allelic diversity observed in mullets from the southernmost portion of the Atlantic coast of Brazil and from Argentina. This may be taken into account when designing fisheries management plans involving Brazilian, Uruguayan and Argentinean M. liza populations.

Proxy comparisons for Paleogene sea water temperature reconstructions

NASA Astrophysics Data System (ADS)

de Bar, Marijke; de Nooijer, Lennart; Schouten, Stefan; Ziegler, Martin; Sluijs, Appy; Reichart, Gert-Jan

2017-04-01

Several studies have reconstructed Paleogene seawater temperatures, using single- or multi-proxy approaches (e.g. Hollis et al., 2012 and references therein), particularly comparing TEX86 with foraminiferal δ18O and Mg/Ca. Whereas trends often agree relatively well, absolute temperatures can differ significantly between proxies, possibly because they are often applied to (extreme) climate events/transitions (e.g. Sluijs et al., 2011), where certain assumptions underlying the temperature proxies may not hold true. A more general long-term multi-proxy temperature reconstruction, is therefore necessary to validate the different proxies and underlying presumed boundary conditions. Here we apply a multi-proxy approach using foraminiferal calcite and organic proxies to generate a low-resolution, long term (80 Myr) paleotemperature record for the Bass River core (New Jersey, North Atlantic). Oxygen (δ18O), clumped isotopes (Δ47) and Mg/Ca of benthic foraminifera, as well as the organic proxies MBT'-CBT, TEX86H, U37K' index and the LDI were determined on the same sediments. The youngest samples of Miocene age are characterized by a high BIT index (>0.8) and fractional abundance of the C32 1,15-diol (>0.6; de Bar et al., 2016) and the absence of foraminifera, all suggesting high continental input and shallow depths. The older sediment layers (˜30 to 90 Ma) display BIT values and C32 1,15-diol fractional abundances <0.3, implying marine conditions. The temperature records (˜30 to 90 Ma) show the global transition from the Cretaceous to Eocene greenhouse world into the icehouse climate. The TEX86H sea surface temperature (SST) record shows a gradual cooling over time of ˜35 to 20 ˚ C, whereas the δ18O-derived bottom water temperatures (BWTs) decrease from ˜20 to 10 ˚ C, and the Mg/Ca and Δ47-derived BWTs decrease from ˜25 to 15 ˚ C. The absolute temperature difference between the δ18O and Δ47, might be explained by local variations in seawater δ18O composition. Similarly, the difference in Mg/Ca- and δ18O-derived BWTs is likely caused by uncertainties in the seawater Mg/Ca model and the relationship between the seawater Mg/Ca and the incorporation of Mg into the foraminiferal shell. The U37K' index could not be calculated as only di-unsaturated alkenones were identified, indicating that SSTs were > 28 ˚ C. In contrast, LDI temperatures were considerably lower and varied only between 21 and 19 ˚ C. MBT'-CBT derived mean annual temperatures for the ages of 9 and 20 Ma align well with the TEX86H SSTs. Overall, the agreement of the paleotemperature proxies in terms of main tendencies, and the covariation with the global benthic oxygen isotope compilation suggests that temperatures in this region varied in concert with global climate variability. The fact that offsets between the different proxies used here remain fairly constant down to 90 Ma ago, indicates that the fundamental mechanisms responsible for the proxy relation to temperature remained constant. de Bar, M. W., et al. (2016), Constraints on the application of long chain diol proxies in the Iberian Atlantic margin, Org. Geochem., 101, 184-195. Hollis, C. J., et al. (2012), Early Paleogene temperature history of the Southwest Pacific Ocean: Reconciling proxies and models, Earth Planet. Sci. Lett., 349, 53-66. Sluijs, A., et al. (2011), Southern ocean warming, sea level and hydrological change during the Paleocene-Eocene thermal maximum, Climate of the Past, 7(1), 47-61.

Growth rates and geochemical proxies in Late Campanian bivalves - New insights from micro-X-ray Fluorescence mapping and numerical growth modelling

NASA Astrophysics Data System (ADS)

de Winter, Niels; Goderis, Steven; van Malderen, Stijn; Vanhaecke, Frank; Claeys, Philippe

2017-04-01

Understanding the Late Cretaceous greenhouse climate is of vital importance for understanding present and future climate change. While a lot of good work has been done to reconstruct climate in this interesting period, most paleoclimatic studies have focused on long-term climate change[1]. Alternatively, multi-proxy records from marine bivalves provide us with a unique opportunity to study past climate on a seasonal scale. However, previous fossil bivalve studies have reported ambiguous results with regard to the interpretation of trace element and stable isotope proxies in marine bivalve shells[2]. One major problem in the interpretation of such records is the bivalve's vital effect and the occurrence of disequilibrium fractionation during bivalve growth. Both these problems are linked to the annual growth cycle of marine bivalves, which introduces internal effects on the incorporation of isotopes and trace elements into the shell[3]. Understanding this growth cycle in extinct bivalves is therefore of great importance for the interpretation of seasonal proxy records in their shells. In this study, three different species of extinct Late Campanian bivalves (two rudist species and one oyster species) that were found in the same stratigraphic interval are studied. Micro-X-Ray Fluorescence line scanning and mapping of trace elements such as Mg, Sr, S and Zn, calibrated by LA-ICP-MS measurements, is combined with microdrilled stable carbon and oxygen isotope analysis on the well-preserved part of the shells. Data of this multi-proxy study is compared with results from a numerical growth model written in the open-source statistics package R[4] and based on annual growth increments observed in the shells and shell thickness. This growth model is used together with proxy data to reconstruct rates of trace element incorporation into the shell and to calculate the mass balance of stable oxygen and carbon isotopes. In order to achieve this goal, 2D mapping of bivalve shell surfaces is combined with high-precision point measurements and linescans to characterize different carbonate facies within the shell and to model changes in proxy data in three dimensions. Comparison of sub-annual variations in growth rate and shell geometry with proxy data sheds light on the degree to which observed seasonal variations in geochemical proxies are dependent on internal mechanisms of shell growth as opposed to external mechanisms such as climatic and environmental change. The use of three different species of bivalve from the same paleoenvironment allows the examination of species-specific responses to environmental change. This study attempts to determine which proxies in which species of bivalve are suitable for paleoenvironmental reconstruction and will aid future paleoseasonality studies in interpreting seasonally resolved multi-proxy records. References 1 DeConto R.M., et al. Cambridge University Press; 2000. 2 Elliot M, et al., PPP 2009. 3 Steuber T. Geology. 1996. 4 R core team, 2004, www.R-project.org

Assessing the spatial representability of charcoal and PAH-based paleofire records with integrated GIS, modelling, and empirical approaches

NASA Astrophysics Data System (ADS)

Vachula, R. S.; Huang, Y.; Russell, J. M.

2017-12-01

Lake sediment-based fire reconstructions offer paleoenvironmental context in which to assess modern fires and predict future burning. However, despite the ubiquity, many uncertainties remain regarding the taphonomy of paleofire proxies and the spatial scales for which they record variations in fire history. Here we present down-core proxy analyses of polycyclic aromatic hydrocarbons (PAHs) and three size-fractions of charcoal (63-150, >150 and >250 μm) from Swamp Lake, California, an annually laminated lacustrine archive. Using a statewide historical GIS dataset of area burned, we assess the spatial scales for which these proxies are reliable recorders of fire history. We find that the coherence of observed and proxy-recorded fire history inherently depends upon spatial scale. Contrary to conventional thinking that charcoal mainly records local fires, our results indicate that macroscopic charcoal (>150 μm) may record spatially broader (<25 km) changes in fire history, and as such, the coarsest charcoal particles (>250 μm) may be a more conservative proxy for local burning. We find that sub-macroscopic charcoal particles (63-150 μm) reliably record regional (up to 150 km) changes in fire history. These results indicate that charcoal-based fire reconstructions may represent spatially broader fire history than previously thought, which has major implications for our understanding of spatiotemporal paleofire variations. Our analyses of PAHs show that dispersal mobility is heterogeneous between compounds, but that PAH fluxes are reliable proxies of fire history within 25-50 km, which suggests PAHs may be a better spatially constrained paleofire proxy than sedimentary charcoal. Further, using a linear discriminant analysis model informed by modern emissions analyses, we show that PAH assemblages preserved in lake sediments can differentiate vegetation type burned, and are thus promising paleoecological biomarkers warranting further research and implementation. In sum, our analyses offer new insight into the spatial dimensions of paleofire proxies and constitute a methodology that can be applied to other locations and proxies to better inform site-specific reconstructions.

Uncertainty in Operational Atmospheric Analyses and Re-Analyses

NASA Astrophysics Data System (ADS)

Langland, R.; Maue, R. N.

2016-12-01

This talk will describe uncertainty in atmospheric analyses of wind and temperature produced by operational forecast models and in re-analysis products. Because the "true" atmospheric state cannot be precisely quantified, there is necessarily error in every atmospheric analysis, and this error can be estimated by computing differences ( variance and bias) between analysis products produced at various centers (e.g., ECMWF, NCEP, U.S Navy, etc.) that use independent data assimilation procedures, somewhat different sets of atmospheric observations and forecast models with different resolutions, dynamical equations, and physical parameterizations. These estimates of analysis uncertainty provide a useful proxy to actual analysis error. For this study, we use a unique multi-year and multi-model data archive developed at NRL-Monterey. It will be shown that current uncertainty in atmospheric analyses is closely correlated with the geographic distribution of assimilated in-situ atmospheric observations, especially those provided by high-accuracy radiosonde and commercial aircraft observations. The lowest atmospheric analysis uncertainty is found over North America, Europe and Eastern Asia, which have the largest numbers of radiosonde and commercial aircraft observations. Analysis uncertainty is substantially larger (by factors of two to three times) in most of the Southern hemisphere, the North Pacific ocean, and under-developed nations of Africa and South America where there are few radiosonde or commercial aircraft data. It appears that in regions where atmospheric analyses depend primarily on satellite radiance observations, analysis uncertainty of both temperature and wind remains relatively high compared to values found over North America and Europe.

Pedagogising Poverty Alleviation: A Discourse Analysis of Educational and Social Policies in Argentina and Chile

ERIC Educational Resources Information Center

Rambla, Xavier; Veger, Antoni

2009-01-01

For the past decades international organisations and governments have promoted and implemented analogous education policies on the grounds that education is the key factor to foster development and fight poverty. This article sets the context of these educational programmes and analyses their discourse on poverty in Argentina and Chile. Then, it…

Major storm periods and climate forcing in the Western Mediterranean during the Late Holocene

NASA Astrophysics Data System (ADS)

Degeai, Jean-Philippe; Devillers, Benoît; Dezileau, Laurent; Oueslati, Hamza; Bony, Guénaëlle

2015-12-01

Big storm events represent a major risk for populations and infrastructures settled on coastal lowlands. In the Western Mediterranean, where human societies colonized and occupied the coastal areas since the Ancient times, the variability of storm activity for the past three millennia was investigated with a multi-proxy sedimentological and geochemical study from a lagoonal sequence. Mappings of the geochemistry and magnetic susceptibility of detrital sources in the watershed of the lagoon and from the coastal barriers were undertaken in order to track the terrestrial or coastal/marine origin of sediments deposited into the lagoon. The multi-proxy analysis shows that coarser material, low magnetic susceptibility, and high strontium content characterize the sedimentological signature of the paleostorm levels identified in the lagoonal sequence. A comparison with North Atlantic and Western Mediterranean paleoclimate proxies shows that the phases of high storm activity occurred during cold periods, suggesting a climatically-controlled mechanism for the occurrence of these storm periods. Besides, an in-phase storm activity pattern is found between the Western Mediterranean and Northern Europe. Spectral analyses performed on the Sr content revealed a new 270-year solar-driven pattern of storm cyclicity. For the last 3000 years, this 270-year cycle defines a succession of ten major storm periods (SP) with a mean duration of 96 ± 54 yr. Periods of higher storm activity are recorded from >680 to 560 cal yr BC (SP10, end of the Iron Age Cold Period), from 140 to 820 cal yr AD (SP7 to SP5) with a climax of storminess between 400 and 800 cal yr AD (Dark Ages Cold Period), and from 1230 to >1800 cal yr AD (SP3 to SP1, Little Ice Age). Periods of low storm activity occurred from 560 cal yr BC to 140 cal yr AD (SP9 and SP8, Roman Warm Period) and from 820 to 1230 cal yr AD (SP4, Medieval Warm Period).

Multiple Types of Memory and Everyday Functional Assessment in Older Adults.

PubMed

Beaver, Jenna; Schmitter-Edgecombe, Maureen

2017-06-01

Current proxy measures for assessing everyday functioning (e.g., questionnaires, performance-based measures, and direct observation) show discrepancies in their rating of functional status. The present study investigated the relationship between multiple proxy measures of functional status and content memory (i.e., memory for information), temporal order memory, and prospective memory in an older adult sample. A total of 197 community-dwelling older adults who did (n = 45) or did not meet (n = 152) criteria for mild cognitive impairment (MCI), completed six different assessments of functional status (two questionnaires, two performance-based tasks, and two direct observation tasks) as well as experimental measures of content memory, prospective memory, and temporal order memory. After controlling for demographics and content memory, the temporal order and prospective memory measures explained a significant amount of variance in all proxy functional status measures. When all variables were entered into the regression analyses, content memory and prospective memory were found to be significant predictors of all measures of functional status, whereas temporal order memory was a significant predictor for the questionnaire and direct observation measures, but not performance-based measures. The results suggest that direct observation and questionnaire measures may be able to capture components of everyday functioning that require context and temporal sequencing abilities, such as multi-tasking, that are not as well captured in many current laboratory performance-based measures of functional status. Future research should aim to inform the development and use of maximally effective and valid proxy measures of functional ability. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of phone versus mail survey methods on the measurement of health-related quality of life and emotional and behavioural problems in adolescents.

PubMed

Erhart, Michael; Wetzel, Ralf M; Krügel, André; Ravens-Sieberer, Ulrike

2009-12-30

Telephone interviews have become established as an alternative to traditional mail surveys for collecting epidemiological data in public health research. However, the use of telephone and mail surveys raises the question of to what extent the results of different data collection methods deviate from one another. We therefore set out to study possible differences in using telephone and mail survey methods to measure health-related quality of life and emotional and behavioural problems in children and adolescents. A total of 1700 German children aged 8-18 years and their parents were interviewed randomly either by telephone or by mail. Health-related Quality of Life (HRQoL) and mental health problems (MHP) were assessed using the KINDL-R Quality of Life instrument and the Strengths and Difficulties Questionnaire (SDQ) children's self-report and parent proxy report versions. Mean Differences ("d" effect size) and differences in Cronbach alpha were examined across modes of administration. Pearson correlation between children's and parents' scores was calculated within a multi-trait-multi-method (MTMM) analysis and compared across survey modes using Fisher-Z transformation. Telephone and mail survey methods resulted in similar completion rates and similar socio-demographic and socio-economic makeups of the samples. Telephone methods resulted in more positive self- and parent proxy reports of children's HRQoL (SMD < or = 0.27) and MHP (SMD < or = 0.32) on many scales. For the phone administered KINDL, lower Cronbach alpha values (self/proxy Total: 0.79/0.84) were observed (mail survey self/proxy Total: 0.84/0.87). KINDL MTMM results were weaker for the phone surveys: mono-trait-multi-method mean r = 0.31 (mail: r = 0.45); multi-trait-mono-method mean (self/parents) r = 0.29/0.36 (mail: r = 0.34/0.40); multi-trait-multi-method mean r = 0.14 (mail: r = 0.21). Weaker MTMM results were also observed for the phone administered SDQ: mono-trait-multi-method mean r = 0.32 (mail: r = 0.40); multi-trait-mono-method mean (self/parents) r = 0.24/0.30 (mail: r = 0.20/0.32); multi-trait-multi-method mean r = 0.14 (mail = 0.14). The SDQ classification into borderline and abnormal for some scales was affected by the method (OR = 0.36-1.55). The observed differences between phone and mail surveys are small but should be regarded as relevant in certain settings. Therefore, while both methods are valid, some changes are necessary. The weaker reliability and MTMM validity associated with phone methods necessitates improved phone adaptations of paper and pencil questionnaires. The effects of phone versus mail survey modes are partly different across constructs/measures.

"Tango Feroz": Teaching a History of Politics and Economics of Argentina through Sex, Drugs, and Rock and Roll

ERIC Educational Resources Information Center

Romero, Eva Karene

2015-01-01

This article directly resulted from the teacher/researcher experience, describing new analyses resulting from subtitling a film for curriculum incorporation: "Tango feroz, la leyenda de Tanguito" (1993). Set in Argentina in the sixties and loosely based on the life of José Alberto Iglesias Correa, also known as Tanguito, this film…

Quasi-State Monopoly of the Education System and Socio-Economic Segregation in Argentina

ERIC Educational Resources Information Center

Narodowski, Mariano; Gottau, Verónica; Moschetti, Mauro

2016-01-01

This paper analyses the provision of education in Argentina in systemic terms. Using the concept of quasi-monopoly and the notions of exit, voice and loyalty, we study the logic of organization and distribution of students within the educational system. We support the idea that the provision of private and public education makes a coherent whole,…

Munroa argentina, a Grass of the South American Transition Zone, Survived the Andean Uplift, Aridification and Glaciations of the Quaternary

PubMed Central

Amarilla, Leonardo D.; Anton, Ana M.; Chiapella, Jorge O.; Manifesto, María M.; Angulo, Diego F.; Sosa, Victoria

2015-01-01

The South American Transition Zone (SATZ) is a biogeographic area in which not only orogeny (Andes uplift) and climate events (aridification) since the mid-Miocene, but also Quaternary glaciation cycles had an important impact on the evolutionary history of the local flora. To study this effect, we selected Munroa argentina, an annual grass distributed in the biogeographic provinces of Puna, Prepuna and Monte. We collected 152 individuals from 20 localities throughout the species’ range, ran genetic and demographic analyses, and applied ecological niche modeling. Phylogenetic and population genetic analyses based on cpDNA and AFLP data identified three phylogroups that correspond to the previously identified subregions within the SATZ. Molecular dating suggests that M. argentina has inhabited the SATZ since approximately 3.4 (4.2–1.2) Ma and paleomodels predict suitable climate in these areas during the Interglacial period and the Last Glacial Maximum. We conclude that the current distribution of M. argentina resulted from the fragmentation of its once continuous range and that climate oscillations promoted ecological differences that favored isolation by creating habitat discontinuity. PMID:26110533

Population Structure and Gene Flow of the Yellow Anaconda (Eunectes notaeus) in Northern Argentina

PubMed Central

McCartney-Melstad, Evan; Waller, Tomás; Micucci, Patricio A.; Barros, Mariano; Draque, Juan; Amato, George; Mendez, Martin

2012-01-01

Yellow anacondas (Eunectes notaeus) are large, semiaquatic boid snakes found in wetland systems in South America. These snakes are commercially harvested under a sustainable management plan in Argentina, so information regarding population structuring can be helpful for determination of management units. We evaluated genetic structure and migration using partial sequences from the mitochondrial control region and mitochondrial genes cyt-b and ND4 for 183 samples collected within northern Argentina. A group of landscape features and environmental variables including several treatments of temperature and precipitation were explored as potential drivers of observed genetic patterns. We found significant population structure between most putative population comparisons and bidirectional but asymmetric migration in several cases. The configuration of rivers and wetlands was found to be significantly associated with yellow anaconda population structure (IBD), and important for gene flow, although genetic distances were not significantly correlated with the environmental variables used here. More in-depth analyses of environmental data may be needed to fully understand the importance of environmental conditions on population structure and migration. These analyses indicate that our putative populations are demographically distinct and should be treated as such in Argentina's management plan for the harvesting of yellow anacondas. PMID:22675425

Climate variability in China during the last millennium based on reconstructions and simulations

NASA Astrophysics Data System (ADS)

García-Bustamante, E.; Luterbacher, J.; Xoplaki, E.; Werner, J. P.; Jungclaus, J.; Zorita, E.; González-Rouco, J. F.; Fernández-Donado, L.; Hegerl, G.; Ge, Q.; Hao, Z.; Wagner, S.

2012-04-01

Multi-decadal to centennial climate variability in China during the last millennium is analysed. We compare the low frequency temperature and precipitation variations from proxy-based reconstructions and palaeo-simulations from climate models. Focusing on the regional responses to the global climate evolution is of high relevance due to the complexity of the interactions between physical mechanisms at different spatio-temporal scales and the potential severity of the derived multiple socio-economic impacts. China stands out as a particularly interesting region, not only due to its complex climatic features, ranging from the semiarid northwestern Tibetan Plateau to the tropical monsoon southeastern climates, but also because of its wealth of proxy data. However, comprehensive assessments of proxy- and model-based information about palaeo-climatic variations in China are, to our knowledge, still lacking. In addition, existing studies depict a general lack of agreement between reconstructions and model simulations with respect to the amplitude and/or occurrence of warmer/colder and wetter/drier periods during the last millennium and the magnitude of the 20th century warming trend. Furthermore, these works are mainly focused on eastern China regions that show a denser proxy data coverage. We investigate how last millennium palaeo-runs compare to independent evidences from an unusual large number of proxy reconstructions over the study area by employing state-of-the-art palaeo-simulations with multi-member ensembles from the CMIP5/PMIP3 project. This shapes an ideal frame for the evaluation of the uncertainties associated to internal and intermodel model variability. Preliminary results indicate that despite the strong regional and seasonal dependencies, temperature reconstructions in China evidence coherent variations among all regions at centennial scale, especially during the last 500 years. The spatial consistency of low frequency temperature changes is an interesting aspect and of relevance for the assessment of forced climatic responses in China. The comparison between reconstructions and simulations from climate models show that, apart from the 20th century warming trend, the variance of the reconstructed mean China temperature lies in the envelope (uncertainty range) spanned by the temperature simulations. The uncertainty arises from the internal (multi-member ensembles) and the inter-model variability. Centennial variations tend to be broadly synchronous in the reconstructions and the simulations. However, the simulations show a delay of the warm period 1000-1300 AD. This warm medieval period both in the simulations and the reconstructions is followed by cooling till 1800 AD. Based on the simulations, the recent warming is not unprecedented and is comparable to the medieval warming. Further steps of this study will address the individual contribution of anthropogenic and natural forcings on climate variability and change during the last millennium in China. We will make use of of models that provide runs including single forcings (fingerprints) for the attribution of climate variations from decadal to multi-centennial time scales. With this aim, we will implement statistical techniques for the detection of optimal signal-to-noise-ratio between external forcings and internal variability of reconstructed temperatures and precipitation. To apply these approaches the uncertainties associated with both reconstructions and simulations will be estimated. The latter will shed some light into the mechanisms behind current climate evolution and will help to constrain uncertainties in the sensitivity of model simulations to increasing CO2 scenarios of future climate change. This work will also contribute to the overall aims of the PAGES 2k initiative in Asia (http://www.pages.unibe.ch/workinggroups/2k-network)

A population-based study of cognitive impairment in socially vulnerable adults in Argentina. The Matanza Riachuelo study preliminary results

PubMed Central

Bartoloni, Leonardo; Blatt, Graciela; Insua, Iván; Furman, Mariano; González, María Agustina; Hermann, Bárbara; Kesselman, Mariana; Massautis, Alicia; Reinado, Alejandra; Senas, Patricia; Yavitz, Claudia; Lejarraga, Horacio; Nunes, Fernando; Arizaga, Raúl Luciano; Allegri, Ricardo F

2014-01-01

Population aging has taken place intensively worldwide, even in developing countries. These countries have population groups with low resources and basic unmet needs that are frequently omitted from epidemiological studies. Objective The purpose of this study was to determine the prevalence of cognitive impairment (CI) and dementia in an economic and socially vulnerable population from Argentina. Methods A door-to-door observational population-based survey among adults over 60 years of cognitive impairment and dementia in the social vulnerable area of the Matanza Riachuelo Basin, in the suburban area of Buenos Aires, Argentina was conducted. Trained psychologists interviewed subjects and a proxy informant. A standardized protocol including a socio-demographic questionnaire, the Mini-Mental State Examination, the Geriatric Depression Scale and a functional inventory for IADL and ADL was administered. Diagnoses were divided into three general categories: normal cognitive function, cognitive impairment-no dementia (CIND) and dementia. Results and Conclusions A total of 2437 elderly persons were assessed, of which 73.6% fulfilled inclusion criteria. The prevalence of CI among those over 60 was 26.4% (18.1% CIND and 8.3% dementia) with higher prevalence of dementia in younger individuals than rates reported in developed counties, probably due to low control of vascular risk factors. This information can help inform health public decisions in the generation of programs and plans for the prevention, diagnosis and treatment of cognitive impairment in this type of socially vulnerable population. PMID:29213923

A population-based study of cognitive impairment in socially vulnerable adults in Argentina. The Matanza Riachuelo study preliminary results.

PubMed

Bartoloni, Leonardo; Blatt, Graciela; Insua, Iván; Furman, Mariano; González, María Agustina; Hermann, Bárbara; Kesselman, Mariana; Massautis, Alicia; Reinado, Alejandra; Senas, Patricia; Yavitz, Claudia; Lejarraga, Horacio; Nunes, Fernando; Arizaga, Raúl Luciano; Allegri, Ricardo F

2014-01-01

Population aging has taken place intensively worldwide, even in developing countries. These countries have population groups with low resources and basic unmet needs that are frequently omitted from epidemiological studies. The purpose of this study was to determine the prevalence of cognitive impairment (CI) and dementia in an economic and socially vulnerable population from Argentina. A door-to-door observational population-based survey among adults over 60 years of cognitive impairment and dementia in the social vulnerable area of the Matanza Riachuelo Basin, in the suburban area of Buenos Aires, Argentina was conducted. Trained psychologists interviewed subjects and a proxy informant. A standardized protocol including a socio-demographic questionnaire, the Mini-Mental State Examination, the Geriatric Depression Scale and a functional inventory for IADL and ADL was administered. Diagnoses were divided into three general categories: normal cognitive function, cognitive impairment-no dementia (CIND) and dementia. A total of 2437 elderly persons were assessed, of which 73.6% fulfilled inclusion criteria. The prevalence of CI among those over 60 was 26.4% (18.1% CIND and 8.3% dementia) with higher prevalence of dementia in younger individuals than rates reported in developed counties, probably due to low control of vascular risk factors. This information can help inform health public decisions in the generation of programs and plans for the prevention, diagnosis and treatment of cognitive impairment in this type of socially vulnerable population.

A new multi-proxy reconstruction of Atlantic deep ocean circulation during the warm mid-Pliocene

NASA Astrophysics Data System (ADS)

Riesselman, C. R.; Dowsett, H. J.; Scher, H. D.; Robinson, M. M.

2011-12-01

The mid-Pliocene (3.264 - 3.025 Ma) is the most recent interval in Earth's history with sustained global temperatures in the range of warming predicted for the 21st century, providing an appealing analog with which to examine the Earth system changes we might encounter in the coming century. Ongoing sea surface and deep ocean temperature reconstructions and coupled ocean-atmosphere general circulation model simulations by the USGS PRISM (Pliocene Research Interpretation and Synoptic Mapping) Group identify a dramatic North Atlantic warm anomaly coupled with increased evaporation in the mid-Pliocene, possibly driving enhanced meridional overturning circulation and North Atlantic Deep Water production. However deep ocean temperature is not a conclusive proxy for water mass, and most coupled model simulations predict transient decreases in North Atlantic Deep Water production in 21st century, presenting a contrasting picture of future warmer worlds. Here, we present early results from a new multi-proxy reconstruction of Atlantic deep ocean circulation during the warm mid-Pliocene, using δ13C of benthic foraminifera as a proxy for water mass age and the neodymium isotopic imprint on fossil fish teeth as a proxy for water mass source region along a three-site depth transect from the Walvis Ridge (subtropical South Atlantic). The deep ocean circulation reconstructions resulting from this project will add a new dimension to the PRISM effort and will be useful for both initialization and evaluation of future model simulations.

The Pliocene to recent history of the Kuroshio and Tsushima Currents: a multi-proxy approach

NASA Astrophysics Data System (ADS)

Gallagher, Stephen J.; Kitamura, Akihisa; Iryu, Yasufumi; Itaki, Takuya; Koizumi, Itaru; Hoiles, Peter W.

2015-12-01

The Kuroshio Current is a major western boundary current controlled by the North Pacific Gyre. It brings warm subtropical waters from the Indo-Pacific Warm Pool to Japan exerting a major control on Asian climate. The Tsushima Current is a Kuroshio offshoot transporting warm water into the Japan Sea. Various proxies are used to determine the paleohistory of these currents. Sedimentological proxies such as reefs, bedforms, sediment source and sorting reveal paleocurrent strength and latitude. Proxies such as coral and mollusc assemblages reveal past shelfal current activity. Microfossil assemblages and organic/inorganic geochemical analyses determine paleo- sea surface temperature and salinity histories. Transportation of tropical palynomorphs and migrations of Indo-Pacific species to Japanese waters also reveal paleocurrent activity. The stratigraphic distribution of these proxies suggests the Kuroshio Current reached its present latitude (35 °N) by ~3 Ma when temperatures were 1 to 2 °C lower than present. At this time a weak Tsushima Current broke through Tsushima Strait entering the Japan Sea. Similar oceanic conditions persisted until ~2 Ma when crustal stretching deepened the Tsushima Strait allowing inflow during every interglacial. The onset of stronger interglacial/glacial cycles ~1 Ma was associated with increased North Pacific Gyre and Kuroshio Current intensity. This triggered Ryukyu Reef expansion when reefs reached their present latitude (~31 °N), thereafter the reef front advanced (~31 °N) and retreated (~25 °N) with each cycle. Foraminiferal proxy data suggests eastward deflection of the Kuroshio Current from its present path at 24 °N into the Pacific Ocean due to East Taiwan Channel restriction during the Last Glacial Maximum. Subsequently Kuroshio flow resumed its present trajectory during the Holocene. Ocean modeling and geochemical proxies show that the Kuroshio Current path may have been similar during glacials and interglacials, however the glacial mode of this current remains controversial. Paleohistorical studies form important analogues for current behavior with future climate change, however, there are insufficient studies at present in the region that may be used for this purpose. Modeling of the response of the Kuroshio Current to future global warming reveals that current velocity may increase by up to 0.3 m/sec associated with a northward migration of the Kuroshio Extension.

Synthesizing late Holocene paleoclimate reconstructions: Lessons learned, common challenges, and implications for future research

NASA Astrophysics Data System (ADS)

Rodysill, J. R.

2017-12-01

Proxy-based reconstructions provide vital information for developing histories of environmental and climate changes. Networks of spatiotemporal paleoclimate information are powerful tools for understanding dynamical processes within the global climate system and improving model-based predictions of the patterns and magnitudes of climate changes at local- to global-scales. Compiling individual paleoclimate records and integrating reconstructed climate information in the context of an ensemble of multi-proxy records, which are fundamental for developing a spatiotemporal climate data network, are hindered by challenges related to data and information accessibility, chronological uncertainty, sampling resolution, climate proxy type, and differences between depositional environments. The U.S. Geological Survey (USGS) North American Holocene Climate Synthesis Working Group has been compiling and integrating multi-proxy paleoclimate data as part of an ongoing effort to synthesize Holocene climate records from North America. The USGS North American Holocene Climate Synthesis Working Group recently completed a late Holocene hydroclimate synthesis for the North American continent using several proxy types from a range of depositional environments, including lakes, wetlands, coastal marine, and cave speleothems. Using new age-depth relationships derived from the Bacon software package, we identified century-scale patterns of wetness and dryness for the past 2000 years with an age uncertainty-based confidence rating for each proxy record. Additionally, for highly-resolved North American lake sediment records, we computed average late Holocene sediment deposition rates and identified temporal trends in age uncertainty that are common to multiple lakes. This presentation addresses strengths and challenges of compiling and integrating data from different paleoclimate archives, with a particular focus on lake sediments, which may inform and guide future paleolimnological studies.

Publication bias in obesity treatment trials?

PubMed

Allison, D B; Faith, M S; Gorman, B S

1996-10-01

The present investigation examined the extent of publication bias (namely the tendency to publish significant findings and file away non-significant findings) within the obesity treatment literature. Quantitative literature synthesis of four published meta-analyses from the obesity treatment literature. Interventions in these studies included pharmacological, educational, child, and couples treatments. To assess publication bias, several regression procedures (for example weighted least-squares, random-effects multi-level modeling, and robust regression methods) were used to regress effect sizes onto their standard errors, or proxies thereof, within each of the four meta-analysis. A significant positive beta weight in these analyses signified publication bias. There was evidence for publication bias within two of the four published meta-analyses, such that reviews of published studies were likely to overestimate clinical efficacy. The lack of evidence for publication bias within the two other meta-analyses might have been due to insufficient statistical power rather than the absence of selection bias. As in other disciplines, publication bias appears to exist in the obesity treatment literature. Suggestions are offered for managing publication bias once identified or reducing its likelihood in the first place.

Characterizing phantom arteries with multi-channel laser ultrasonics and photo-acoustics.

PubMed

Johnson, Jami L; van Wijk, Kasper; Sabick, Michelle

2014-03-01

Multi-channel photo-acoustic and laser ultrasonic waves are used to sense the characteristics of proxies for healthy and diseased vessels. The acquisition system is non-contacting and non-invasive with a pulsed laser source and a laser vibrometer detector. As the wave signatures of our targets are typically low in amplitude, we exploit multi-channel acquisition and processing techniques. These are commonly used in seismology to improve the signal-to-noise ratio of data. We identify vessel proxies with a diameter on the order of 1 mm, at a depth of 18 mm. Variations in scattered and photo-acoustic signatures are related to differences in vessel wall properties and content. The methods described have the potential to improve imaging and better inform interventions for atherosclerotic vessels, such as the carotid artery. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Mid-late Holocene climate, demography, and cultural dynamics in Iberia: A multi-proxy approach

NASA Astrophysics Data System (ADS)

Lillios, Katina T.; Blanco-González, Antonio; Drake, Brandon Lee; López-Sáez, José Antonio

2016-03-01

Despite increasing interest in the relationship between culture transformation and abrupt climate change, their complexities are poorly understood. The local impact of global environmental fluctuations depends on multiple factors, and their effects on societal collapse are often assumed rather than demonstrated. One of the major changes in west European later prehistory was the Copper to Bronze Age transition, contemporaneous with the 4.2 ky cal. BP event. This article offers a multi-dimensional insight into this historical process in the Iberian Peninsula from a multi-proxy and comparative perspective. Three study areas, representative of diverse ecological settings and historical trajectories, are compared. Using radiocarbon dates, 13C discrimination (Δ13C) values on C3 plants, and high-resolution palynological records as palaeoclimatic and palaeodemographic proxies, this study tracks the uneven signals of Holocene climate. The wettest Northwest region features the most stable trend lines, whereas the Southwest exhibits an abrupt decrease in its demographic signals c. 4500 cal. BP, which is then followed by a subsequent rise in the neighbouring Southeast. These lines of evidence suggest the possibility, never previously noted, of demic migration from the Southwest to the Southeast in the Early Bronze Age as a contributing factor to the cultural dynamics of southern Iberia.

Extending isotopic fractionation in phytoplankton for Phanerozoic pCO2 reconstruction

NASA Astrophysics Data System (ADS)

Witkowski, C. R.; Agostini, S.; Weijers, J.; Schouten, S.; S Sinninghe Damsté, J.

2017-12-01

The atmospheric concentration of carbon dioxide (pCO2) is a keystone in many earth system dynamics, including the biosphere, carbon cycle, and climate. In order to better understand the impact of today's exceptional increases in pCO2 on the future, we look to secular trends in pCO2. Photosynthetic carbon isotopic fractionation (Ɛp), calculated from the difference between the stable carbon isotopic composition (δ13C) of environmental CO2 and biomass, has some of the lowest uncertainty in estimation among CO2 proxies. However, Ɛp is generally applied to species-specific compounds which have an evolution-limited record (e.g. alkenones limited ca. 50 Ma). To extend the use of Ɛp, we explore the general phytoplankton biomarker phytane. As the fossilized side-chain of chlorophyll, phytane is spatially and temporally ubiquitous, with the potential to record pCO2 back to the earliest photoautotrophs in the geologic record. To develop and validate its potential as a pCO2 proxy, we explored phytane in modern environments, in a multi-proxy case study, and in a Phanerozoic reconstruction. As a proof-of-concept, the δ13C of phytane was tested in modern environments at naturally-occurring CO2 vents in Japan and Italy, which showed clear fractionation over the steep CO2 gradient. This was then further tested in a multi-proxy assessment in DSDP site 467 that spans the last 15 Ma, looking at both well-established (i.e. alkenones) and potential (i.e. phytane, steranes, hopanes) pCO2 proxies; phytane represented the average δ13C for these biomarkers. Finally, the δ13C of phytane data over the Phanerozoic was compiled, showing agreement with literature reconstructions of pCO2. Current pCO2 reconstructions are derived from many different types of proxies, which can create incongruities and inconsistencies throughout time, making this single well-constrained proxy that ubiquitously spans the geologic record a useful addition to the palaeo-detective's toolbox.

Evidence of Himalayan uplift as seen in Neogene records of Indian monsoon variability from ODP Hole 722B, NW Arabian Sea

NASA Astrophysics Data System (ADS)

Muthusamy, Prakasam; Gupta, Anil K.; Saini, Naresh K.

2013-04-01

The Indian monsoon is one of the most interesting climatic features on Earth impacting most populous countries of South and East Asia. It is marked by seasonal reversals of wind direction with southwesterly winds in summer (June-September) and northeasterly winds in winter (December-February). The monsoon not only impacts socioeconomic conditions of Asia but also brings important changes in fauna and flora, ocean upwelling and primary productivity in the Arabian Sea. The Himalaya has undergone several phases of rapid uplift and exhumation since the early Miocene which led to major intensification of the Indian monsoon. The monsoon is driven by the thermal contrast between land and sea, and is intimately linked with the latitudinal movement of the Inter-Tropical Convergence Zone (ITCZ). The effect of Indian monsoon variability and the Himalayan uplift can be seen in numerous proxy records across the region. In this study we discussed about the Indian monsoon intensification and the Himalayan uplift since the early Miocene based on multi proxy records such as planktic foraminiferal relative abundances (Globigerina bulloides, Globigerinita glutinata and mixed layer species), total organic carbon (TOC), CaCO3 and elemental data from ODP Hole 722B (2028 mbsf), northwestern Arabian Sea. The TOC, CaCO3 and elemental variations of the ODP Hole 722B suggest multi phase of monsoonal intensification and Himalayan uplifts. Our results suggest that in the early Miocene (23.03 Ma) to ~15Ma, the wind strength and productivity were low. A major change is observed at ~15 Ma, during which time numerous proxies show abrupt changes. TOC, CaCO3 and Elemental analyses results reveal that a major change in the productivity, wind strength and chemical weathering starts around 15 Ma and extends up to 10 Ma. This suggests that a major Himalayan uplift occurred during ~15-10 Ma that drove Indian monsoon intensification. A similar change is also observed during 5 to 1 Ma. These long-term paleoclimatic trends correlated to Himalayan uplift. Major peaks in various proxy records correspond with enhanced monsoonal strength and the Himalayan uplift. Keywords: Indian monsoon; Himalayan uplift; Arabian Sea; Productivity; Planktic foraminifera; Total Organic Carbon

Characteristics and Changes in the Mathematics Textbooks for the Secondary School in Argentina along 67 Years

ERIC Educational Resources Information Center

Llanos, Viviana Carolina; Otero, Maria Rita

2018-01-01

This work analyses the changes in the relationship between arguing and images from the mathematics textbooks for the secondary school in Argentina (students 12-17 years old) along 67 years. The textbooks have been published in the period 1940 thru 2007. The analysis is done by (N = 137) textbooks based on three metacategories in an inductive way.…

A widening gap? The political and social organization of childcare in Argentina.

PubMed

Faur, Eleonor

2011-01-01

This article examines how social policies and programmes implemented in Argentina shape the political and social organization of childcare. The author seeks to analyse how welfare institutions are currently responding to emerging needs, and to what extent they facilitate the defamilialization of childcare for different social classes. Because Argentina lacks a truly unified ‘care policy’, four different kinds of facilities and programmes are examined: employment-based childcare services; pre-school schemes; social assistance care services; and poverty reduction strategies. It is argued that far from offering equal rights and services with a universalist cast, these ‘caring’ institutions reflect the ethos of the current welfare model in Argentina: a fragmented set of social policies based on different assumptions for different social groups, which in turn filter down to the social organization of childcare.

Statistical link between external climate forcings and modes of ocean variability

NASA Astrophysics Data System (ADS)

Malik, Abdul; Brönnimann, Stefan; Perona, Paolo

2017-07-01

In this study we investigate statistical link between external climate forcings and modes of ocean variability on inter-annual (3-year) to centennial (100-year) timescales using de-trended semi-partial-cross-correlation analysis technique. To investigate this link we employ observations (AD 1854-1999), climate proxies (AD 1600-1999), and coupled Atmosphere-Ocean-Chemistry Climate Model simulations with SOCOL-MPIOM (AD 1600-1999). We find robust statistical evidence that Atlantic multi-decadal oscillation (AMO) has intrinsic positive correlation with solar activity in all datasets employed. The strength of the relationship between AMO and solar activity is modulated by volcanic eruptions and complex interaction among modes of ocean variability. The observational dataset reveals that El Niño southern oscillation (ENSO) has statistically significant negative intrinsic correlation with solar activity on decadal to multi-decadal timescales (16-27-year) whereas there is no evidence of a link on a typical ENSO timescale (2-7-year). In the observational dataset, the volcanic eruptions do not have a link with AMO on a typical AMO timescale (55-80-year) however the long-term datasets (proxies and SOCOL-MPIOM output) show that volcanic eruptions have intrinsic negative correlation with AMO on inter-annual to multi-decadal timescales. The Pacific decadal oscillation has no link with solar activity, however, it has positive intrinsic correlation with volcanic eruptions on multi-decadal timescales (47-54-year) in reconstruction and decadal to multi-decadal timescales (16-32-year) in climate model simulations. We also find evidence of a link between volcanic eruptions and ENSO, however, the sign of relationship is not consistent between observations/proxies and climate model simulations.

Gender, age, social disadvantage and quitting smoking in Argentina and Uruguay.

PubMed

Niedzin, Mirosław; Gaszyńska, Ewelina; Krakowiak, Jan; Saran, Tomasz; Szatko, Franciszek; Kaleta, Dorota

2018-03-14

Cessation of tobacco use has the potential to provide the greatest immediate benefits for tobacco control. Understanding the social determinants of smoking cessation is an essential requirement for increasing smoking cessation at the population level. The purpose of this study was to analyze the socio-economic dimensions associated with cessation success among adults in Argentina and Uruguay. Data from the Global Adult Tobacco Survey (GATS), a cross-sectional, population-based, nationally representative survey conducted in Argentina (n=5,383) and Uruguay (n=4,833) was utilized. Univariable and multivariable logistic regression analyses with results being presented as odds ratios (OR) with 95% confidence intervals were applied to study differences among those respondents who sustained smoking abstinence (≥1 year) and those who continued smoking. The GATS study revealed that social gradients in tobacco quitting exist in Argentina and Uruguay. Being aged 25-34, particularly men in Uruguay, women in Argentina, low educated men in Argentina and having a lower asset index were associated with reduced odds for quitting. Factors that are driving differences in smoking cessation between diverse social groups in Latin America countries need to be considered when implementing relevant interventions to ensure tobacco control strategies work effectively for all population segments.

A point-by-point multi-scale surface temperature reconstruction method and tests by pseudo proxy experiments

NASA Astrophysics Data System (ADS)

Chen, X.

2016-12-01

This study present a multi-scale approach combining Mode Decomposition and Variance Matching (MDVM) method and basic process of Point-by-Point Regression (PPR) method. Different from the widely applied PPR method, the scanning radius for each grid box, were re-calculated considering the impact from topography (i.e. mean altitudes and fluctuations). Thus, appropriate proxy records were selected to be candidates for reconstruction. The results of this multi-scale methodology could not only provide the reconstructed gridded temperature, but also the corresponding uncertainties of the four typical timescales. In addition, this method can bring in another advantage that spatial distribution of the uncertainty for different scales could be quantified. To interpreting the necessity of scale separation in calibration, with proxy records location over Eastern Asia, we perform two sets of pseudo proxy experiments (PPEs) based on different ensembles of climate model simulation. One consist of 7 simulated results by 5 models (BCC-CSM1-1, CSIRO-MK3L-1-2, HadCM3, MPI-ESM-P, and Giss-E2-R) of the "past1000" simulation from Coupled Model Intercomparison Project Phase 5. The other is based on the simulations of Community Earth System Model Last Millennium Ensemble (CESM-LME). The pseudo-records network were obtained by adding the white noise with signal-to-noise ratio (SNR) increasing from 0.1 to 1.0 to the simulated true state and the locations mainly followed the PAGES-2k network in Asia. Totally, 400 years (1601-2000) simulation was used for calibration and 600 years (1001-1600) for verification. The reconstructed results were evaluated by three metrics 1) root mean squared error (RMSE), 2) correlation and 3) reduction of error (RE) score. The PPE verification results have shown that, in comparison with ordinary linear calibration method (variance matching), the RMSE and RE score of PPR-MDVM are improved, especially for the area with sparse proxy records. To be noted, in some periods with large volcanic activities, the RMSE of MDVM get larger than VM for higher SNR cases. It should be inferred that the volcanic eruptions might blur the intrinsic characteristics of multi-scales variabilities of the climate system and the MDVM method would show less advantage in that case.

Extreme Seasonality During Early Eocene Hyperthermals

NASA Astrophysics Data System (ADS)

Plink-Bjorklund, P.; Birgenheier, L.

2012-12-01

An outcrop multi-proxy dataset from the Uinta Basin, Utah, US indicates that extreme seasonality occurred repeatedly during the Early Eocene transient global warming events (hyperthermals), during the Palaeocene-Eocene Thermal Maximum (PETM) as well as during the six consequent younger hyperthermals. In this multi-proxy analysis we have investigated the precipitation distribution and peakedness changes during Early Eocene hyperthermals. This dataset is different from previously published terrestrial climate proxy analyses, in that we fully utilize the sedimentary record itself, and especially the hydrodynamic indicators within the river strata. We combine these high-resolution sedimentologic-stratigraphic analyses, with analyses of terrestrial burrowing traces, and the conventional palaeosol and stable carbon isotope analyses. With this approach, we are able to better document hydroclimatologic changes, and identify climate seasonality changes, rather than just long-term mean humidity/aridity and temperature trends. For this study we analyzed over 1000 m of Palaeocene and Early Eocene river and lake strata in the Uinta Basin, Utah, US (Figs. 1 and 2). The sedimentologic-stratigraphic analyses of outcrops included measuring detailed stratigraphic sections, analyzing photopanels, a spatial GPS survey, and lateral walk-out of stratigraphic packages across an area of 300 km2, with additional data across an area of ca 6000 km2 (Fig. 2). Continental burrowing traces and palaeosols were analyzed along the measured sections. For geochemical analysis 196 samples of mudrock facies were collected along the measured sections and analyzed for total organic carbon (Corg), total nitrogen (Ntot), and δ13C values of bulk organic matter. Biostratigraphy (25), radiometric dates, and carbon isotope stratigraphy, using bulk δ13C of organic matter in floodplain siltstones confirm the position of the PETM and the 6-8 post-PETM hyperthermals in the studied strata The seasonality intensification is seen as short intense rain seasons alternating with prolonged droughts. Such seasonality intensification had a profound effect on landscape morphology as well as on vegetation. River systems changed from braided streams to highly seasonal fluvial megafans with tens of meters deep channels. River channels staid dry through most of the prolonged droughts, as witnessed by intra-channel insect burrows and paleosols. The intense wet seasons caused extremely high water discharge in channels, resulting in high rates of erosion, sediment transport and deposition. As a result, the channels were filled locally by up to 10s of meters of sediment, causing rapid river course changes and terrestrial flooding. Particulate organic matter content is extremely low in these sediments. This is in contrast to river sediments that were deposited during less intense seasonality. The dataset was compared to other datasets from intermontane basins in the Western Interior and also Europe (Spain), where similar seasonality changes are indicated to have occurred during the PETM. This is in great contrast to intermontane Early Eocene river systems documented in Norwegian Arctic (e.g. Spitsbergen) and in tropics (e.g. Venezuela), where no seasonality intensification has been documented. Thus the seasonality intensification seems to have been confined to (northern) mid-latitudes and subtropics.

Intra-regional classification of grape seeds produced in Mendoza province (Argentina) by multi-elemental analysis and chemometrics tools.

PubMed

Canizo, Brenda V; Escudero, Leticia B; Pérez, María B; Pellerano, Roberto G; Wuilloud, Rodolfo G

2018-03-01

The feasibility of the application of chemometric techniques associated with multi-element analysis for the classification of grape seeds according to their provenance vineyard soil was investigated. Grape seed samples from different localities of Mendoza province (Argentina) were evaluated. Inductively coupled plasma mass spectrometry (ICP-MS) was used for the determination of twenty-nine elements (Ag, As, Ce, Co, Cs, Cu, Eu, Fe, Ga, Gd, La, Lu, Mn, Mo, Nb, Nd, Ni, Pr, Rb, Sm, Te, Ti, Tl, Tm, U, V, Y, Zn and Zr). Once the analytical data were collected, supervised pattern recognition techniques such as linear discriminant analysis (LDA), partial least square discriminant analysis (PLS-DA), k-nearest neighbors (k-NN), support vector machine (SVM) and Random Forest (RF) were applied to construct classification/discrimination rules. The results indicated that nonlinear methods, RF and SVM, perform best with up to 98% and 93% accuracy rate, respectively, and therefore are excellent tools for classification of grapes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Late Cretaceous paleosols as paleoclimate proxies of high-latitude Southern Hemisphere: Mata Amarilla Formation, Patagonia, Argentina

NASA Astrophysics Data System (ADS)

Varela, Augusto N.; Raigemborn, M. Sol; Richiano, Sebastián; White, Tim; Poiré, Daniel G.; Lizzoli, Sabrina

2018-01-01

Although there is general consensus that a global greenhouse climate characterized the mid-Cretaceous, details of the climate state of the mid-Cretaceous Southern Hemisphere are less clearly understood. In particular, continental paleoclimate reconstructions are scarce and exclusively derived from paleontological records. Using paleosol-derived climofunction studies of the mid- to Upper Cretaceous Mata Amarilla Formation, southern Patagonia, Argentina, we present a reconstruction of the mid-Cretaceous climate of southern South America. Our results indicate that at 60° south paleolatitude during the Cenomanian-Santonian stages, the climate was subtropical temperate-warm (12 °C ± 2.1 °C) and humid (1404 ± 108 mm/yr) with marked rainfall seasonality. These results are consistent with both previous estimations from the fossil floras of the Mata Amarilla Formation and other units of the Southern Hemisphere, and with the previous observations of the displacement of tropical and subtropical floras towards the poles in both hemispheres. The data presented here show a more marked seasonality and slightly lower mean annual precipitation and mean annual temperature values than those recorded at the same paleolatitudes in the Northern Hemisphere.

Millennial-scale climate variations in western Mediterranean during late Pleistocene-early Holocene: multi-proxy analyses from Padul peatbog (southern Iberian Peninsula)

NASA Astrophysics Data System (ADS)

Camuera, Jon; Jiménez-Moreno, Gonzalo; José Ramos-Román, María; García-Alix, Antonio; Jiménez-Espejo, Francisco; Toney, Jaime L.; Anderson, R. Scott; Kaufman, Darrell; Bright, Jordon; Sachse, Dirk

2017-04-01

Padul peatbog, located in southern Iberian Peninsula (western Mediterranean region) is a unique area for palaeoenvironmental studies due to its location, between arid and temperate climates. Previous studies showed that the Padul peatbog contains a continuous record of the last ca. 0.8-1 Ma, so it is an extraordinary site to identify glacial-interglacial phases as well as Heinrich and D-O events, linked to orbital- and suborbital-scale variations. In 2015, a new 42 m long core was taken from this area, providing an excellent sediment record probably for the last ca. 300,000 years. This study is focused on the paleoenvironmental and climatic reconstruction of the late Pleistocene and the early Holocene (ca. from 50,000 to 9,500 cal. yrs BP), using AMS 14C and AAR dating, high-resolution pollen analysis, lithology, continuous XRF-scanning, X-ray diffraction, magnetic susceptibility and organic geochemistry. These different proxies provide information not only about the regional environment change but also about local changes in the conditions of the Padul lake/peatbog due to variations in water temperature, pH or nutrients.

Internal Climatic Influences From Secular To Multi-decadal Scales: Comparison Of NAO Reconstructions.

NASA Astrophysics Data System (ADS)

Nicolle, M.; Debret, M.; Massei, N.; de Vernal, A.

2017-12-01

In the Northern Hemisphere, the North Atlantic Oscillation (NAO) is the major dominant mode of variability in winter atmospheric circulation, with large impacts on temperature, precipitation and storm tracks in the North Atlantic sector. To understand the role of this internal climatic oscillations on the past climate variability, several proxy-based reconstructions of the NAO were published during the last decades. Two of them are available during the past 1,200 years: a first NAO reconstruction published by Trouet et al. (2009) and a second proposed by Ortega et al. (2015). The major discrepancy between the two reconstructions concerns the transition period between the Medieval Climate Anomaly (MCA) and the Little Ice Age. The first NAO reconstruction shows persistent positive phases during the MCA (AD 1000-1300) but this dominant trend is not highlighted in the reconstruction proposed by Ortega et al. (2015), asking the question of the influence of predictors used to reconstruct the NAO signal during the last millennia. In these study, we compare the two NAO reconstructions in order to determine the effect of bi-proxy or multi-proxy approach on the signal reconstructed. Using statistical and wavelet analysis methods, we conclude that the number of predictors used do not have impact on the signal reconstruct. The two reconstructions signals are characterized by similar variabilities expressed from multi-decadal to multi-secular scales. The major trend difference seems to be link to the type of the predictor and particularly the use of Greenland ice cores in the reconstruction proposed in 2015.

High-resolution multi-proxy reconstruction of Lake Ighiel (Western Carpathians, Romania): processes and controlling factors of lacustrine dynamics during the mid and late Holocene

NASA Astrophysics Data System (ADS)

Haliuc, Aritina; Veres, Daniel; Hubay, Katalin; Begy, Robert; Brauer, Achim; Hutchinson, Simon; Braun, Mihaly

2016-04-01

Concerns about current and prospective environmental change have increased the interest in past climate variability and its impact on the bio-hydro-atmosphere and human society. Acting as high-resolution terrestrial archives, lacustrine sediments are the result of the complex interaction between internal and external forcing and an important tool in efforts to resolve questions related to the palaeoclimatic and palaeoenvironmental conditions of the recent past. Here we discuss a new, high-resolution sedimentary record from the Romanian Carpathians (central-eastern Europe). Lake Ighiel (46° 10'50"N, 23° 22'00"E) is a small lake located in a mid-altitude mountain belt (Trascau Mountains) at an altitude of 924 m ( lake maximum depth 9 m; catchment area 487 ha). We employ detailed 210Pb and 14C dating coupled with high-resolution X-ray fluorescence scanning (μ-XRF) measurements, long-core sedimentary logging, environmental magnetic proxies (susceptibility, natural and induced remanences) in an attempt to trace the 6000 years evolution of lake-catchment system. More specifically, we discuss: i) the temporal evolution of the main sedimentation phases of the lake based on sedimentological, geochemical and magnetic proxies; ii) the amplitude and interplay of processes (natural and/or anthropogenic) controlling the depositional environment through time; iii) assess the contribution of each controlling factors and reconstruct the evolution of lacustrine system and palaeoclimate forcing using multivariate statistics. The sedimentary record can be divided into six phases based on alternating high and low detrital fluxes, oscillating lacustrine productivity and redox conditions. A series of detrital events (5200; 4800; 5400; 5250; 4500; 4050; 3800; 3500; 3250; 3050; 2650; 2350; 2250; 1400; 1100; 500; 100 cal yr BP) were identified by microfacies analyses and X-ray fluorescence scanning (μ-XRF) analysis. These events are reflected in most of the parameters and appear synchronous with climatically induced forcing such as increased regional precipitation and decreased total solar radiation. These changes are superimposed on clear anthropogenic derived contributions reflecting natural and mineral resource exploitation during the early metal ages, the Roman and Medieval periods, as well as during the recent period. The comparison of the our proxies with similarly resolved records from central-eastern Europe highlight the potential of Lake Ighiel as a record of palaeoclimatic and palaeohydrological conditions in a region still lacking high-resolution multi-proxy palaeoenvironmental archives. The authors acknowledge financial support from project PN-II-ID-PCE-2012-4-0530 "Millennial-scale geochemical records of anthropogenic impact and natural climate change in the Romanian Carpathians", contract nr. 15/02.09.2013.

Psychological Needs, Engagement, and Work Intentions: A Bayesian Multi-Measurement Mediation Approach and Implications for HRD

ERIC Educational Resources Information Center

Shuck, Brad; Zigarmi, Drea; Owen, Jesse

2015-01-01

Purpose: The purpose of this study was to empirically examine the utility of self-determination theory (SDT) within the engagement-performance linkage. Design/methodology/approach: Bayesian multi-measurement mediation modeling was used to estimate the relation between SDT, engagement and a proxy measure of performance (e.g. work intentions) (N =…

Arctic temperature and moisture trends during the past 2000 years - Progress from multiproxy-paleoclimate data compilations

NASA Astrophysics Data System (ADS)

Kaufman, Darrell; Routson, Cody; McKay, Nicholas; Beltrami, Hugo; Jaume-Santero, Fernando; Konecky, Bronwen; Saenger, Casey

2017-04-01

Instrumental climate data and climate-model projections show that Arctic-wide surface temperature and precipitation are positively correlated. Higher temperatures coincide with greater moisture by: (1) expanding the duration and source area for evaporation as sea ice retracts, (2) enhancing the poleward moisture transport, and (3) increasing the water-vapor content of the atmosphere. Higher temperature also influences evaporation rate, and therefore precipitation minus evaporation (P-E), the climate variable often sensed by paleo-hydroclimate proxies. Here, we test whether Arctic temperature and moisture also correlate on centennial timescales over the Common Era (CE). We use the new PAGES2k multiproxy-temperature dataset along with a first-pass compilation of moisture-sensitive proxy records to calculate century-scale composite timeseries, with a focus on longer records that extend back through the first millennium CE. We present a new Arctic borehole temperature reconstruction as a check on the magnitude of Little Ice Age cooling inferred from the proxy records, and we investigate the spatial pattern of centennial-scale variability. Similar to previous reconstructions, v2 of the PAGES2k proxy temperature dataset shows that, prior to the 20th century, mean annual Arctic-wide temperature decreased over the CE. The millennial-scale cooling trend is most prominent in proxy records from glacier ice, but is also registered in lake and marine sediment, and trees. In contrast, the composite of moisture-sensitive (primarily P-E) records does not exhibit a millennial-scale trend. Determining whether fluctuations in the mean state of Arctic temperature and moisture were in fact decoupled is hampered by the difficulty in detecting a significant trend within the relatively small number of spatially heterogeneous multi-proxy moisture-sensitive records. A decoupling of temperature and moisture would indicate that evaporation had a strong counterbalancing effect on precipitation and/or that shifting circulation patterns overwhelmed any multi-centennial-scale co-variability.

Correlating wine quality indicators to chemical and sensory measurements.

PubMed

Hopfer, Helene; Nelson, Jenny; Ebeler, Susan E; Heymann, Hildegarde

2015-05-12

Twenty-seven commercial Californian Cabernet Sauvignon wines of different quality categories were analyzed with sensory and chemical methods. Correlations between five quality proxies-points awarded during a wine competition, wine expert scores, retail price, vintage, and wine region-were correlated to sensory attributes, volatile compounds, and elemental composition. Wine quality is a multi-faceted construct, incorporating many different layers. Depending on the quality proxy studied, significant correlations between quality and attributes, volatiles and elements were found, some of them previously reported in the literature.

Validation of Spacecraft Active Cavity Radiometer Total Solar Irradiance (TSI) Long Term Measurement Trends Using Proxy TSI Least Squares Analyses

NASA Technical Reports Server (NTRS)

Lee, Robert Benjamin, III; Wilson, Robert S.

2003-01-01

Long-term, incoming total solar irradiance (TSI) measurement trends were validated using proxy TSI values, derived from indices of solar magnetic activity. Spacecraft active cavity radiometers (ACR) are being used to measure longterm TSI variability, which may trigger global climate changes. The TSI, typically referred to as the solar constant, was normalized to the mean earth-sun distance. Studies of spacecraft TSI data sets confirmed the existence of a 0.1 %, long-term TSI variability component within a 10-year period. The 0.1% TSI variability component is clearly present in the spacecraft data sets from the 1984-2004 time frame. Typically, three overlapping spacecraft data sets were used to validate long-term TSI variability trends. However, during the years of 1978-1984, 1989-1991, and 1993-1996, three overlapping spacecraft data sets were not available in order to validate TSI trends. The TSI was found to vary with indices of solar magnetic activity associated with recent 10-year sunspot cycles. Proxy TSI values were derived from least squares analyses of the measured TSI variability with the solar indices of 10.7-cm solar fluxes, and with limb-darked sunspot fluxes. The resulting proxy TSI values were compared to the spacecraft ACR measurements of TSI variability to detect ACR instrument degradation, which may be interpreted as TSI variability. Analyses of ACR measurements and TSI proxies are presented primarily for the 1984-2004, Earth Radiation Budget Experiment (ERBE) ACR solar monitor data set. Differences in proxy and spacecraft measurement data sets suggest the existence of another TSI variability component with an amplitude greater than or equal to 0.5 Wm-2 (0.04%), and with a cycle of 20 years or more.

Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)

NASA Astrophysics Data System (ADS)

Kotthoff, Ulrich; Groeneveld, Jeroen; Ash, Jeanine L.; Fanget, Anne-Sophie; Quintana Krupinski, Nadine; Peyron, Odile; Stepanova, Anna; Warnock, Jonathan; Van Helmond, Niels A. G. M.; Passey, Benjamin H.; Rønø Clausen, Ole; Bennike, Ole; Andrén, Elinor; Granoszewski, Wojciech; Andrén, Thomas; Filipsson, Helena L.; Seidenkrantz, Marit-Solveig; Slomp, Caroline P.; Bauersachs, Thorsten

2017-12-01

Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial), paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059) over the past ˜ 8000 years and evaluate the applicability of inorganic- and organic-based proxies in this particular setting. All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index) show that lacustrine conditions occurred in the Little Belt until ˜ 7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish-marine conditions of the Littorina Sea stage (more saline and warmer) occurred within ˜ 200 years when the connection to the Kattegat became established after ˜ 7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity. The reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 °C for bottom waters and up to 16 °C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg  /  Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEXL86) can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant changes in depositional settings: in the case of our study, the change from freshwater to marine conditions. Our study shows that particular caution has to be taken when applying and interpreting proxies in coastal environments and marginal seas, where water mass conditions can experience more rapid and larger changes than in open ocean settings. Approaches using a multitude of independent proxies may thus allow a more robust paleoenvironmental assessment.

The Association of Proxy Care Engagement with Proxy Reports of Patient Experience and Quality of Life.

PubMed

Roydhouse, Jessica K; Gutman, Roee; Keating, Nancy L; Mor, Vincent; Wilson, Ira B

2018-05-27

To assess the association of proxy-specific covariates with proxy-reported patient cancer care experience, quality rating, and quality of life. Secondary analysis of data from the Cancer Care Outcomes Research and Surveillance (CanCORS) study. Cross-sectional observational study. The respondents were proxies for patients with incident colorectal or lung cancer. Analyses used linear regression models and adjusted for patient sociodemographic and clinical characteristics. Outcomes included patients' experiences with medical care, nursing care, and care coordination, overall quality ratings, and physical and mental health, all scored on 0-100 scales (0 = worst, 100 = best). Independent variables included the proxy's relationship with the patient and engagement in patient care. Of 1,011 proxies, most were the patient's spouse (50 percent) or child (36 percent). Although most proxies (66 percent) always attended medical visits, 3 percent reported never attending. After adjustment, on average children reported worse experiences and poorer quality care than spouses (4-9 points lower across outcomes). Proxies who never attended medical visits reported significantly worse medical care (-11 points, 95 percent CI = -18 to -3) and care coordination (-13 points, 95 percent CI = -20 to -6). Collecting data on proxy engagement in care is warranted if proxy responses are used. © Health Research and Educational Trust.

A multi-proxy record of MIS 11-12 deglaciation and glacial MIS 12 instability from the Sulmona basin (central Italy)

NASA Astrophysics Data System (ADS)

Regattieri, Eleonora; Giaccio, Biagio; Galli, Paolo; Nomade, Sebastien; Peronace, Edoardo; Messina, Paolo; Sposato, Andrea; Boschi, Chiara; Gemelli, Maurizio

2016-01-01

A multi-proxy record (lithology, XRF, CaCO3 content, carbonate δ18O and δ13C) was acquired from a sediment core drilled in the intermountain Sulmona basin (central Italy). Tephrostratigraphic analyses of three volcanic ash layers ascribe the investigated succession to the MIS 12-MIS 11 period, spanning the interval ca. 500-410 ka. Litho-pedo facies assemblage indicates predominant lacustrine deposition, interrupted by a minor sub-aerial and lake low stand episode. Variations in major and minor elements concentrations are related to changes in the clastic input to the lake. The oxygen isotopic composition of carbonate (δ18Oc) intervals is interpreted mainly as a proxy for the amount of precipitation in the high-altitude catchment of the karst recharge system. The record shows pronounced hydrological variability at orbital and millennial time-scales, which appears closely related to the Northern Hemisphere summer insolation pattern and replicates North Atlantic and west Mediterranean Sea Surface Temperature (SST) fluctuations. The MIS 12 glacial inception is marked by an abrupt reduction of precipitation, lowering of the lake level and enhanced catchment erosion. A well-defined and isotopically prominent interstadial with increased precipitation maybe related to insolation maxima-precession minima at ca. 465 ka. This interstadial ends abruptly at ca. 457 ka and it is followed by a phase of strong short-term instability. Drastic lake-level lowering and enhanced clastic flux characterized the MIS 12 glacial maximum. Lacustrine deposition restarted about 440 ka ago. The MIS 12-MIS 11 transition is characterized by a rapid increase in the precipitation, lake-level rise and reduction in the clastic input, interrupted by a short and abrupt return to drier conditions. Comparison with marine records from the Iberian margin and western Mediterranean suggests that major events of ice rafted debris deposition, related to southward migrations of the polar front, match the harshest periods in central Italy. This indicates strong teleconnections between Northern hemisphere ice sheet dynamics, North Atlantic oceanic conditions and Mediterranean continental hydrology.

Using Resin-Based 3D Printing to Build Geometrically Accurate Proxies of Porous Sedimentary Rocks.

PubMed

Ishutov, Sergey; Hasiuk, Franciszek J; Jobe, Dawn; Agar, Susan

2018-05-01

Three-dimensional (3D) printing is capable of transforming intricate digital models into tangible objects, allowing geoscientists to replicate the geometry of 3D pore networks of sedimentary rocks. We provide a refined method for building scalable pore-network models ("proxies") using stereolithography 3D printing that can be used in repeated flow experiments (e.g., core flooding, permeametry, porosimetry). Typically, this workflow involves two steps, model design and 3D printing. In this study, we explore how the addition of post-processing and validation can reduce uncertainty in the 3D-printed proxy accuracy (difference of proxy geometry from the digital model). Post-processing is a multi-step cleaning of porous proxies involving pressurized ethanol flushing and oven drying. Proxies are validated by: (1) helium porosimetry and (2) digital measurements of porosity from thin-section images of 3D-printed proxies. 3D printer resolution was determined by measuring the smallest open channel in 3D-printed "gap test" wafers. This resolution (400 µm) was insufficient to build porosity of Fontainebleau sandstone (∼13%) from computed tomography data at the sample's natural scale, so proxies were printed at 15-, 23-, and 30-fold magnifications to validate the workflow. Helium porosities of the 3D-printed proxies differed from digital calculations by up to 7% points. Results improved after pressurized flushing with ethanol (e.g., porosity difference reduced to ∼1% point), though uncertainties remain regarding the nature of sub-micron "artifact" pores imparted by the 3D printing process. This study shows the benefits of including post-processing and validation in any workflow to produce porous rock proxies. © 2017, National Ground Water Association.

Do patient and proxy agree? Long-term changes in multiple sclerosis physical impact and walking ability on patient-reported outcome scales.

PubMed

Sonder, Judith M; Balk, Lisanne J; Bosma, Libertje V A E; Polman, Chris H; Uitdehaag, Bernard M J

2014-10-01

Patient-reported outcome scales (PROs) are useful in monitoring changes in multiple sclerosis (MS) over time. Although these scales are reliable and valid measures in longitudinal studies in MS patients, it is unknown what the impact is when obtaining longitudinal data from proxies. The objective of this paper is to compare longitudinal changes in patient and proxy responses on PROs assessing physical impact of MS and walking ability. In a prospective observational study, data on the Multiple Sclerosis Impact Scale (MSIS-29 physical) and Multiple Sclerosis Walking Scale (MSWS-12) were obtained from 137 patient-proxy couples at baseline and at two-year follow-up. Demographic and disease-related variables explaining agreement or disagreement between patients and proxies were investigated using linear regression analyses. Full agreement was found in 56% (MSIS) and 62% (MSWS) of the patient-proxy couples. Complete disagreement was very rare for both scales (2% MSIS, 5% MSWS). When patients were more positive than proxies, a higher age, longer disease duration, longer patient-proxy relationship and increased levels of depression, anxiety and caregiver burden in proxies were observed. In the majority of the patient-proxy couples there was agreement. Proxies can serve as a valuable source of information, but caution remains essential when using scores from proxies. © The Author(s), 2014.

A Multi-proxy Approach to Using Cave Sediment Carbon Isotopes for Late Holocene Paleoenvironmental Reconstruction in Florida

NASA Astrophysics Data System (ADS)

Polk, J. S.; van Beynen, P.

2007-12-01

Carbon isotopes from cave sediments collected from Jennings Cave in Marion County, Florida were analyzed using a multi-proxy approach. Fulvic acids (FAs), humic acids (HAs), black carbon, phytoliths, and bulk organic matter were extracted from the sediments for carbon isotope analysis to determine periods of vegetation change caused by climatic influences during the Late Holocene (~\\ 2,800 years BP). The carbon isotope record ranges from -35‰ to -14‰, exhibiting variability of ~\\ -21‰, within the different proxies, which indicates changes between C3 and C4 vegetation. This likely indicates changes between a sub-tropical forested environment and more arid, grassy plains conditions. These changes in plant assemblages were in response to changes in available water resources, with increased temperatures and evapotranspiration leading to arid conditions and a shift toward less C3 vegetation (increased C4 vegetation) during the MWP. The cave sediment fulvic acid cabon isotopes record agrees well with ä13C values from a speleothem collected nearby that covers the same time period. Prolonged migration of the NAO and ITCZ affects precipitation in Florida and likely caused vegetation changes during these climatic shifts.

Does Multi-morbidity Mediate the Effect of Socioeconomics on Self-rated Health? Cross-country Differences

PubMed Central

Assari, Shervin; Lankarani, Maryam Moghani

2015-01-01

Background: This study explored cross-country differences in how multi-morbidity explains the effects of socioeconomic characteristics on self-rated health. Methods: The study borrowed data from the Research on Early Life and Aging Trends and Effects. Participants were 44,530 individuals (age > 65 years) who were sampled from 15 countries (i.e. United States, China, India, Russia, Costa Rica, Puerto Rico, Mexico, Argentina, Barbados, Brazil, Chile, Cuba, Uruguay, Ghana and South Africa). Multi-morbidity was measured as number of chronic medical conditions. In Model I, main effects of socioeconomic factors on self-rated health were calculated using country-specific logistic regressions. In Model II, number of chronic conditions were also added to the models to find changes in coefficients for demographic and socioeconomic factors. Results: In the United States, number of chronic medical conditions explained the effect of income on subjective health. In Puerto Rico, number of chronic medical conditions explained the effect of marital status on subjective health. In Costa Rica, Argentina, Barbados, Cuba, and Uruguay, number of chronic medical conditions explained gender disparities in subjective health. In China, Mexico, Brazil, Russia, Chile, India, Ghana and South Africa, number of chronic medical conditions did not explain the effect of demographic or socioeconomic factors on subjective health. Conclusions: Multi-morbidity explains the effect of demographic and socioeconomic factors on subjective health in some but not other countries. Further research is needed. PMID:26445632

Litigation in Argentina: challenging the tobacco industry

PubMed Central

Flores, M L; Barnoya, J; Mejia, R; Alderete, E; Pérez‐Stable, E J

2006-01-01

Objective To evaluate the processes and outcomes of tobacco litigation in Argentina and to analyse the strategies of the tobacco industry to oppose litigation using tobacco industry documents. Methods A systematic search of tobacco industry documents on the internet dating from 1978 to 2002. Law library searches using Argentinean official and unofficial reports systems were combined with computerised online searches. Results There have been at least 15 failed litigation cases in Argentina and the tobacco industry presented a concerted defence in every claim regardless of cost. We categorised 11 cases as product liability and nicotine addiction, two as health care reimbursement, and two as criminal law and secondhand smoke. Industry strategies included hiring legal consultants from prestigious international and Argentinean law firms and developing litigation prevention programmes. Industry monitored legal academic meetings, controlled the development of new product liability legislation, obtained favourable opinions from experts, and closely observed the development of litigation in Argentina. Conclusion The strategies used by the industry have been successful in preventing recovery for tobacco injuries through litigation. Argentinean health advocates and lawyers need to be aware of the roles and strategies of the tobacco industry in order to develop effective litigation in Argentina. PMID:16565455

Litigation in Argentina: challenging the tobacco industry.

PubMed

Flores, M L; Barnoya, J; Mejia, R; Alderete, E; Pérez-Stable, E J

2006-04-01

To evaluate the processes and outcomes of tobacco litigation in Argentina and to analyse the strategies of the tobacco industry to oppose litigation using tobacco industry documents. A systematic search of tobacco industry documents on the internet dating from 1978 to 2002. Law library searches using Argentinean official and unofficial reports systems were combined with computerised online searches. There have been at least 15 failed litigation cases in Argentina and the tobacco industry presented a concerted defence in every claim regardless of cost. We categorised 11 cases as product liability and nicotine addiction, two as health care reimbursement, and two as criminal law and secondhand smoke. Industry strategies included hiring legal consultants from prestigious international and Argentinean law firms and developing litigation prevention programmes. Industry monitored legal academic meetings, controlled the development of new product liability legislation, obtained favourable opinions from experts, and closely observed the development of litigation in Argentina. The strategies used by the industry have been successful in preventing recovery for tobacco injuries through litigation. Argentinean health advocates and lawyers need to be aware of the roles and strategies of the tobacco industry in order to develop effective litigation in Argentina.

Multi-proxy evidence for climate-driven changes in arctic lakes from northern Russia over the Holocene.

NASA Astrophysics Data System (ADS)

Self, Angela; Brooks, Stephen; Jones, Vivienne; Solovieva, Nadia; McGowan, Suzanne; Rosén, Peter; Parrott, Emily; Seppä, Heikki; Salonen, Sakari

2010-05-01

Average arctic temperatures have increased at almost twice the rate of the rest of the world over the last 100 years and climate projections suggest this trend is likely to continue resulting in an additional warming of 2 - 3°C in annual mean air temperatures by 2050. Freshwater ecosystems occupy a substantial area of the terrestrial environment in the Arctic and are particularly sensitive to temperature increases which may lead to profound changes in catchment characteristics, permafrost, hydrology and nutrient availability. Therefore it is important to understand how past changes in climate have affected these ecosystems. In this paper we present one of the first quantitative multi-proxy climate records from arctic Siberia. The affect of early - mid Holocene and recent climate change on arctic lakes in northern Russia were investigated in multi-proxy studies. The past climate was reconstructed using chironomid inference models to estimate mean July air temperatures and trends in continentality. Stable isotopes and LOI were analysed to infer past changes in sediment organic matter. Near-infrared spectroscopy (NIRS) and/or diatoms were used to infer changes in lake water total organic carbon and algal pigments and/or diatoms were used to infer changes in productivity and light penetration in the lake. Analyses of a sediment core from a tundra lake (Lake Kharinei) in north-eastern European Russia show significant assemblage changes in diatoms, chironomids and pigments, which coincide with climate-driven vegetation shifts from open birch forest to spruce forest and then to tundra over the Holocene. During the open birch phase of the late Glacial - early Holocene, chironomid-inferred reconstructions suggest that the climate was approximately 1 - 3°C warmer and more continental than present. Isotopic analyses indicate a productive environment receiving a significant input of organic material from terrestrial plants into the lake. Both diatoms and NIRS-TOC also suggest that the lake water was relatively high in TOC. Spruce forest became established within the catchment during the early - mid Holocene, which appears to have stimulated algal production. Throughout this period July air temperatures are inferred to have gradually declined to present-day values and the climate became more maritime. From ca. 4000 cal yrs BP July air temperatures remained stable but continentality increased leading to a shorter ice-free period. The pollen and macrofossil record indicates a transition to tundra vegetation ca 3000 cal yr BP which coincides with major changes in pigments, chironomids and diatoms. High resolution reconstruction of climate variability over the last 200 years from two tundra lakes on the Putoran Plateau, western Siberia, suggest that mean July air temperatures warmed by approximately 0.5°C between ca 1820 - 1980 and have remained relatively stable over the last 30 years. However major compositional changes in the chironomid and diatom assemblages have occurred within the last 125 - 50 years. Since the 1970s increases in the instrumental June temperature record and a chironomid-inferred shift to a more maritime climate have been accompanied by increases in diatom accumulation rates together with an increase in within-lake productivity and a trend towards increased algal productivity (as highlighted by stable isotope analysis). The synchronicity of the changes suggests the biota may be responding to lengthening of the ice-free period and related limnological changes. The changes in these Russian lakes corroborate results from Europe and Arctic Canada and indicate a circumpolar pattern of climate-driven regime change in arctic lakes in the last 100 years.

Late Glacial to Holocene environmental variabilities: A new multi-proxy paleolimnological study of sedimentary sequences from Como (northern Italy)

NASA Astrophysics Data System (ADS)

Höbig, N.; Martinelli, E.; Motella, S.; Michetti, A. M.; Livio, F.; Tinner, W.; Reicherter, K.; Castelletti, L.

2012-04-01

Lake Como (northern Italy) is the deepest Italian lake, reaching a depth of about 425 m. The lambda-shaped lake expands about 45 km in NE-SW direction. Southwards of the hydrologically closed western branch, two sediment cores of 70 m (S1) and 65 m length (S2) were taken in the year 2005 close to the cathedral of Como (Piazza Verdi). The drilling sites are located in the middle of the Southern Alps, some 300 m from the present-day lakeshore. The cores provide the first detailed Late Glacial to Holocene multi-proxy record for the Lake Como basin. Our research is aimed at investigating the environmental and geological evolution of the Insubria Region. The multi-proxy study of the stratigraphic sequences contain geophysical, geotechnical, sedimentological, paleobotanical, and radiocarbon analyses. They have been performed for core S1 and are still in progress on core S2. With this data the working group focuses on two main issues. The first topic is the reconstruction of the natural and anthropogenic processes controlling the ground subsidence in the Como urban area (e.g., Comerci et al., 2007) and another aim is to reconstruct vegetation and land-use dynamics. In particular, 150 samples of vegetal macroremains have been collected in the palustrine deposits along S1 core, down to 31,00 m. Below this depth (dated 14C 12,496 ± 55 yr BP - 15,050 - 14,250 cal yr BP), the amount of plant macroremains in the sediment drops dramatically. The taxonomic determination was carried out on more than 800 macroremains. They are represented by fragments of wood, leaves, needles, seeds, fruits, mosses and tiny charcoals (Motella, 2009, unpublished PhD Thesis). Picea/Larix, Pinus sp., Juniperus with Betula, found in the deeper levels (30.80 - 30.00 m), are the first arboreal taxa that colonized the shores of Lake Como, and show that the reforestation began in this area about 16,000 years ago. During the early Holocene (25.10 m) Abies alba expanded and further upwards the sequence mixed deciduous forests became important. Preliminary results of palynological analyses for a section of the core S2 (35.04 - 18.12 m), show Late Glacial sediments in the depth of 35.04 - 31.16 m, due to vegetation changes related to natural climatic variability, with an alternation of communities typical of cold (Poaceae, Artemisia, Juniperus, Pinus and Betula) and temperate climates (e.g. Quercus). Later, during the Holocene, forests composed by mostly deciduous broadleaves and Abies alba expanded. During the mid and late Holocene human impact increased and modified vegetation. This is shown by the increase of herbs and heliofilous shrubs (26.51 m), typical of deforested spaces for fields and pastures. Human exploitation of wood is represented for example by the dramatic decline of Abies alba (24.97 m). Finally, the increase of Cerealia (19.39 m) is clearly related to intensified agricultural activities. The results of further paleobotanical and geophysical analyses which are in progress will be presented during the conference. Moreover, geochemical measurements (e.g., XRF) will be performed in future for core S2. Researches realized within the project of Italy-Switzerland Cooperation SITINET "Censimento, valorizzazione e messa in rete di siti geologici e archeologici" (Census, increase of value and computerization of geological and archaeological sites). Interreg IV A "Geo-Archeositi dell'Insubria" (Geo-Archaeosites of Insubria).

Timescale dependence of the relationship between the East Asian summer monsoon strength and precipitation over eastern China in the last millennium

NASA Astrophysics Data System (ADS)

Shi, Jian; Yan, Qing; Wang, Huijun

2018-04-01

Precipitation/humidity proxies are widely used to reconstruct the historical East Asian summer monsoon (EASM) variations based on the assumption that summer precipitation over eastern China is closely and stably linked to the strength of EASM. However, whether the observed EASM-precipitation relationship (e.g., increased precipitation with a stronger EASM) was stable throughout the past remains unclear. In this study, we used model outputs from the Paleoclimate Modelling Intercomparison Project Phase III and Community Earth System Model to investigate the stability of the EASM-precipitation relationship over the last millennium on different timescales. The model results indicate that the EASM strength (defined as the regionally averaged meridional wind) was enhanced in the Medieval Climate Anomaly (MCA; ˜ 950-1250 AD), during which there was increased precipitation over eastern China, and weakened during the Little Ice Age (LIA; ˜ 1500-1800 AD), during which there was decreased precipitation, consistent with precipitation/humidity proxies. However, the simulated EASM-precipitation relationship is only stable on a centennial and longer timescale and is unstable on a shorter timescale. The nonstationary short-timescale EASM-precipitation relationship broadly exhibits a multi-decadal periodicity, which may be attributed to the internal variability of the climate system and has no significant correlation to external forcings. Our results have implications for understanding the discrepancy among various EASM proxies on a multi-decadal timescale and highlight the need to rethink reconstructed decadal EASM variations based on precipitation/humidity proxies.

Culturing Fundamentals Used To Design And Execute A Long-Term Multi-stressor Experiment To Assess Impact Of Deoxygenation, Ocean Acidification, And Warming On Benthic Foraminiferal Community Composition, Growth, And Carbonate Yield: Design And Results

NASA Astrophysics Data System (ADS)

Bernhard, J. M.; Wit, J. C.

2015-12-01

The geochemistry recorded in carbonate foraminiferal tests (shells) is often used as proxy for past oceanographic events and environments. By understanding past oceanic and climatic conditions, we can better predict future climate scenarios, a relevant ability in these times of global change. The fact that foraminifera are biological entities can be pivotal for understanding their geochemical records. Thus, growing foraminifera under known physicochemical conditions and analyzing the geochemistry of their cultured carbonate can yield insightful perspectives for proxy refinement and development. Because parameters often co-vary in nature, proper proxy calibration can only be done with materials grown in strictly controlled and known environments. This presentation will review the various crucial aspects of foraminiferal maintenance and culturing, especially from the perspective of proxy development. These fundamentals were used to design a long-term multi-stressor experiment with oxygen, pCO2 (pH), and temperature as variables to test the single, double or triple threats of deoxygenation, ocean acidification, and oceanic warming. Results on assemblage composition, survivorship and growth of a continental shelf benthic foraminiferal community will be presented. Although one agglutinated morphospecies grew in each of the five treatments, growth of individual calcareous species was more restricted. Initial results indicate that pCO2 was not the factor that impacted communities most. Supported in part by NSF OCE-1219948.

Centennial-scale Holocene climate variations amplified by Antarctic Ice Sheet discharge

NASA Astrophysics Data System (ADS)

Bakker, Pepijn; Clark, Peter U.; Golledge, Nicholas R.; Schmittner, Andreas; Weber, Michael E.

2017-01-01

Proxy-based indicators of past climate change show that current global climate models systematically underestimate Holocene-epoch climate variability on centennial to multi-millennial timescales, with the mismatch increasing for longer periods. Proposed explanations for the discrepancy include ocean-atmosphere coupling that is too weak in models, insufficient energy cascades from smaller to larger spatial and temporal scales, or that global climate models do not consider slow climate feedbacks related to the carbon cycle or interactions between ice sheets and climate. Such interactions, however, are known to have strongly affected centennial- to orbital-scale climate variability during past glaciations, and are likely to be important in future climate change. Here we show that fluctuations in Antarctic Ice Sheet discharge caused by relatively small changes in subsurface ocean temperature can amplify multi-centennial climate variability regionally and globally, suggesting that a dynamic Antarctic Ice Sheet may have driven climate fluctuations during the Holocene. We analysed high-temporal-resolution records of iceberg-rafted debris derived from the Antarctic Ice Sheet, and performed both high-spatial-resolution ice-sheet modelling of the Antarctic Ice Sheet and multi-millennial global climate model simulations. Ice-sheet responses to decadal-scale ocean forcing appear to be less important, possibly indicating that the future response of the Antarctic Ice Sheet will be governed more by long-term anthropogenic warming combined with multi-centennial natural variability than by annual or decadal climate oscillations.

A new high-resolution sediment record from Lake Gościąż (central Poland)

NASA Astrophysics Data System (ADS)

Bonk, Alicja; Błaszkiewicz, Mirosław; Brauer, Achim; Brykała, Dariusz; Gierszewski, Piotr; Kramkowski, Mateusz; Plessen, Brigit; Schwab, Markus; Słowiński, Michał; Tjallingii, Rik

2017-04-01

The varved sediments from Lake Gościąż, located in the Vistula Valley in Central Poland, are an iconic record for palaeoclimate and palaeoenvironmental reconstruction (Goslar et al. 2000, Hajdas et al. 1995, Ralska-Jasiewiczowa et al. 1998). Recently, we obtained a set of new sediment cores from Lake Gościąż and established a 21 m long sediment profile. Except of the topmost part of the core, it is continuously laminated down to glacial sands. We aim at applying a comprehensive multi-proxy core analyses combined with monitoring of present-day sedimentation processes. Sediment investigations will include new methods that have been developed or advanced since the previous studies on the Lake Gościąż sediments including continuous micro-facies analyses, μXRF core scanning and tephrochronology. The main aims of our new project are a revision of the existing floating chronology and to synchronise the Lake Gościąż sediment record based on independent isochrones with other European varved lake records like, e.g. Lake Meerfelder Maar, in order to investigate in detail proxy responses to climate change and to decipher regional leads and lags in climate change. Here, we will present (1) the objectives of our new project on this key record of past climate and environmental change and, (2) preliminary results including magnetic susceptibility, μ-XRF core scanning and microfacies images. This study is a contribution to scientific project financed by the National Science Centre, Poland - No DEC-2015/19/B/ST10/03039.

Phylogeny, diet, and habitat of an extinct ground sloth from Cuchillo Curá, Neuquén Province, southwest Argentina

USGS Publications Warehouse

Hofreiter, Michael; Betancourt, Julio L.; Sbriller, Alicia Pelliza; Markgraf, Vera; McDonald, H. Gregory

2003-01-01

Advancements in ancient DNA analyses now permit comparative molecular and morphological studies of extinct animal dung commonly preserved in caves of semiarid regions. These new techniques are showcased using a unique dung deposit preserved in a late glacial vizcacha (Lagidium sp.) midden from a limestone cave in southwestern Argentina (38.5° S). Phylogenetic analyses of the mitochondrial DNA show that the dung originated from a small ground sloth species not yet represented by skeletal material in the region, and not closely related to any of the four previously sequenced extinct and extant sloth species. Analyses of pollen and plant cuticles, as well as analyses of the chloroplast DNA, show that the Cuchillo Curá ground sloth browsed on many of the same herb, grass, and shrub genera common at the site today, and that its habitat was treeless Patagonian scrub-steppe. We envision a day when molecular analyses are used routinely to supplement morphological identifications and possibly to provide a time-lapse view of molecular diversification.

Phylogeny, diet, and habitat of an extinct ground sloth from Cuchillo Curá, Neuquén Province, southwest Argentina

NASA Astrophysics Data System (ADS)

Hofreiter, Michael; Betancourt, Julio L.; Sbriller, Alicia Pelliza; Markgraf, Vera; McDonald, H. Gregory

2003-05-01

Advancements in ancient DNA analyses now permit comparative molecular and morphological studies of extinct animal dung commonly preserved in caves of semiarid regions. These new techniques are showcased using a unique dung deposit preserved in a late glacial vizcacha ( Lagidium sp.) midden from a limestone cave in southwestern Argentina (38.5° S). Phylogenetic analyses of the mitochondrial DNA show that the dung originated from a small ground sloth species not yet represented by skeletal material in the region, and not closely related to any of the four previously sequenced extinct and extant sloth species. Analyses of pollen and plant cuticles, as well as analyses of the chloroplast DNA, show that the Cuchillo Curá ground sloth browsed on many of the same herb, grass, and shrub genera common at the site today, and that its habitat was treeless Patagonian scrub-steppe. We envision a day when molecular analyses are used routinely to supplement morphological identifications and possibly to provide a time-lapse view of molecular diversification.

Multi-Decadal analysis of Global Trends in Microseism Intensity: A Proxy for Changes in Extremal Storm Activity and Oceanic Wave State

NASA Astrophysics Data System (ADS)

Anthony, R. E.; Aster, R. C.; Rowe, C. A.

2016-12-01

The Earth's seismic noise spectrum features two globally ubiquitous peaks near 8 and 16 s periods (secondary and primary bands) that arise when storm-generated ocean gravity waves are converted to seismic energy, predominantly into Rayleigh waves. Because of its regionally integrative nature, microseism intensity and other seismographic data from long running sites can provide useful proxies for wave state. Expanding an earlier study of global microseism trends (Aster et al., 2010), we analyze digitally-archived, up-to-date (through late 2016) multi-decadal seismic data from stations of global seismographic networks to characterize the spatiotemporal evolution of wave climate over the past >20 years. The IRIS Noise Tool Kit (Bahavair et al., 2013) is used to produce ground motion power spectral density (PSD) estimates in 3-hour overlapping time series segments. The result of this effort is a longer duration and more broadly geographically distributed PSD database than attained in previous studies, particularly for the primary microseism band. Integrating power within the primary and secondary microseism bands enables regional characterization of spatially-integrated trends in wave states and storm event statistics of varying thresholds. The results of these analyses are then interpreted within the context of recognized modes of atmospheric variability, including the particularly strong 2015-2016 El Niño. We note a number of statistically significant increasing trends in both raw microseism power and storm activity occurring at multiple stations in the Northwest Atlantic and Southeast Pacific consistent with generally increased wave heights and storminess in these regions. Such trends in wave activity have the potential to significantly influence coastal environments particularly under rising global sea levels.

Environmental Records from Great Barrier Reef Corals: Inshore versus Offshore Drivers

PubMed Central

Walther, Benjamin D.; Kingsford, Michael J.; McCulloch, Malcolm T.

2013-01-01

The biogenic structures of stationary organisms can be effective recorders of environmental fluctuations. These proxy records of environmental change are preserved as geochemical signals in the carbonate skeletons of scleractinian corals and are useful for reconstructions of temporal and spatial fluctuations in the physical and chemical environments of coral reef ecosystems, including The Great Barrier Reef (GBR). We compared multi-year monitoring of water temperature and dissolved elements with analyses of chemical proxies recorded in Porites coral skeletons to identify the divergent mechanisms driving environmental variation at inshore versus offshore reefs. At inshore reefs, water Ba/Ca increased with the onset of monsoonal rains each year, indicating a dominant control of flooding on inshore ambient chemistry. Inshore multi-decadal records of coral Ba/Ca were also highly periodic in response to flood-driven pulses of terrigenous material. In contrast, an offshore reef at the edge of the continental shelf was subject to annual upwelling of waters that were presumed to be richer in Ba during summer months. Regular pulses of deep cold water were delivered to the reef as indicated by in situ temperature loggers and coral Ba/Ca. Our results indicate that although much of the GBR is subject to periodic environmental fluctuations, the mechanisms driving variation depend on proximity to the coast. Inshore reefs are primarily influenced by variable freshwater delivery and terrigenous erosion of catchments, while offshore reefs are dominated by seasonal and inter-annual variations in oceanographic conditions that influence the propensity for upwelling. The careful choice of sites can help distinguish between the various factors that promote Ba uptake in corals and therefore increase the utility of corals as monitors of spatial and temporal variation in environmental conditions. PMID:24204743

Small mammals taphonomy and environmental evolution during Late Pleistocene-Holocene in Monte Desert: The evidence of Gruta del Indio (central west Argentina)

NASA Astrophysics Data System (ADS)

Fernández, Fernando J.; Pardiñas, Ulyses F. J.

2018-07-01

Very few excavated sequences in southern South America provide an approximation to the environmental evolution covering the segment Late Pleistocene-Holocene. Here we present the taphonomic analysis and paleoenvironmental reconstruction based on the small mammal remains retrieved from the archaeological and paleontological site Gruta del Indio (Mendoza Province, Argentina). Radiocarbon dates situate the small mammal deposits studied within the Late Pleistocene and Holocene. Thus, these assemblages provide a record for inferring environmental evolution in the middle basin of Atuel River during the last ∼31 ky BP. Taphonomic analysis revealed that most of small mammal remains were incorporated by a little destructive nocturnal owl. Recorded species include mainly cricetid and caviomorph rodents and a single marsupial. While Pleistocene assemblages have not exclusive species, the specific richness increases towards the Holocene probably linked with the climatic variability related to ENSO. In overall, the recorded small mammals suggest environmental stability during the Late Pleistocene-Holocene, mostly associated with Monte Desert conditions. Conversely, the pollen sequence studied from Gruta del Indio was interpreted as indicator of a deep environmental change during the Pleistocene-Holocene transition, when the Patagonian steppe was replaced by Monte Desert. Potential biases linked with these kinds of proxies are discussed.

Lead and Lags of Lake System Responses to Late Allerød and Early Younger Dryas Climatic Fluctuation - an Example from Varved Lake Sediments from Northern Poland (Central Europe)

NASA Astrophysics Data System (ADS)

Slowinski, M. M.; Zawiska, I.; Ott, F.; Noryśkiewicz, A. M.; Plessen, B.; Apolinarska, K.; Lutyńska, M.; Michczynska, D. J.; Wulf, S.; Skubała, P.; Błaszkiewicz, M.; Brauer, A.

2014-12-01

The transition from the warmer Allerød to the cooler Younger Dryas period is well understood to represent sudden and extreme climate changes during the end of the last glaciation. Thus, lake sediment studies within paleoclimatic and paleoecological research on this transition are ideal to enhance the knowledge about "lead and lags" of lake system responses to abrupt climate changes through applying multi-proxy sediment analyses. In this study, we present the results of high-resolution studies on varved late glacial sediments from the Trzechowskie paleolake, located in the northern Poland (center Europe). High-resolution bio-proxies (pollen, macrofossils, Cladocera and diatoms), geochemical analyses (µ-XRF data, TOC, C/N ratios, δ18Ocarb and δ13Corg stable isotopes) and a robust chronology based on varve counting, AMS 14C dating and tephrochronology were used to reconstruct the lake system responses to rapid climatic and environmental changes of Trzechowskie paleolake during the late Allerød - Younger Dryas transition. Paleoecological and geochemical analyses, which were carried out in a 4 to 16 years temporal sample resolution, allowed to defining short-termed shifts of the ecosystem that were triggered by abrupt climate changes. The rapid and pronounced cooling at the beginning of the Younger Dryas had a major impact on the lake and its catchment as clearly reflected by not synchronous changes of both, biotic and geochemical proxies. The results of high-resolution analysis indicate (a) an increased precipitation during the Allerød-YD transition, which is responsible for an increase of soil erosion in the catchment during this period, (b) a delayed response of the vegetation compared to the lake depositional system at the YD onset of 20 years, and (c) a non-synchronicity of vegetation responses between Western (Lake Meerfelder Maar) and Eastern European sites (Trzechowskie palaeolake) at the YD onset. This study is a contribution to the Virtual Institute ICLEA (Integrated Climate and Landscape Evolution Analysis) funded by the Helmholtz Association. The research was supported by the National Science Centre Poland (grants No. NN 306085037 and NCN 2011/01/B/ST10/07367).

LA-ICP-MS-derived U-concentrations and microstructural domains within biogenic aragonite of Arctica islandica shell.

PubMed

Helama, Samuli; Heikkilä, Pasi; Rinne, Katja; Nielsen, Jan Kresten; Nielsen, Jesper Kresten

2015-05-01

Understanding of the uranium uptake processes (both in vivo and post-mortem) into the skeletal structures of marine calcifiers is a subject of multi-disciplinary interest. U-concentration changes within the molluscan shell may serve as a paleoceanographic proxy of the pH history. A proxy of this type is needed to track the effects of fossil fuel emissions to ocean acidification. Moreover, attaining reliable U-series dates using shell materials would be a geochronological breakthrough. Picturing the high-resolution changes of U-concentrations in shell profiles is now possible by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Here, we analyzed in situ U-concentration variations in sub-fossilized shells of ocean quahog (Arctica islandica), a commonly studied bivalve species in Quaternary geoscience, using LA-ICP-MS. Microstructural details of the shell profiles were achieved by the scanning electron microscopy (SEM). Comparison of the shell aragonite microstructure with the changes in U-concentration revealed that uranium of possibly secondary origin is concentrated into the porous granular layers of the shell. Our results reinforce the hypothesis that U-concentration variations can be linked with microstructural differences within the shell. A combination of LA-ICP-MS and SEM analyses is recommended as an interesting approach for understanding the U-concentration variations in similar materials.

Liolaemus lizards (Squamata: Liolaemidae) as hosts for the nymph of Amblyomma parvitarsum (Acari: Ixodidae), with notes on Rickettsia infection.

PubMed

Muñoz-Leal, Sebastián; Tarragona, Evelina L; Martins, Thiago F; Martín, Claudia M; Burgos-Gallardo, Freddy; Nava, Santiago; Labruna, Marcelo B; González-Acuña, Daniel

2016-10-01

Adults of Amblyomma parvitarsum are common ectoparasites of South American camelids of the genera Lama and Vicugna, occuring in highlands of Argentina, Bolivia, Chile, Peru and also in Argentinean Patagonia. Whereas larval stages of this tick are known to feed on small lizards, host records for the nymphal instar have remained unreported. Supported by morphological and molecular analyses, herein we report A. parvitarsum nymphs parasitizing two Liolaemus species (Reptilia: Squamata) in the Andean Plateau of Argentina and Chile. Additionally, by a PCR screening targetting gltA and ompA genes, DNA of Rickettsia was detected in one of the collected nymphs. Obtained sequences of this agent were identical to a recent Rickettsia sp. described infecting adults of this tick species in Chile and Argentina.

The Use of Proxy Caches for File Access in a Multi-Tier Grid Environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brun, R.; Dullmann, D.; Ganis, G.

2012-04-19

The use of proxy caches has been extensively studied in the HEP environment for efficient access of database data and showed significant performance with only very moderate operational effort at higher grid tiers (T2, T3). In this contribution we propose to apply the same concept to the area of file access and analyze the possible performance gains, operational impact on site services and applicability to different HEP use cases. Base on a proof-of-concept studies with a modified XROOT proxy server we review the cache efficiency and overheads for access patterns of typical ROOT based analysis programs. We conclude with amore » discussion of the potential role of this new component at the different tiers of a distributed computing grid.« less

Inferring climate variability from skewed proxy records

NASA Astrophysics Data System (ADS)

Emile-Geay, J.; Tingley, M.

2013-12-01

Many paleoclimate analyses assume a linear relationship between the proxy and the target climate variable, and that both the climate quantity and the errors follow normal distributions. An ever-increasing number of proxy records, however, are better modeled using distributions that are heavy-tailed, skewed, or otherwise non-normal, on account of the proxies reflecting non-normally distributed climate variables, or having non-linear relationships with a normally distributed climate variable. The analysis of such proxies requires a different set of tools, and this work serves as a cautionary tale on the danger of making conclusions about the underlying climate from applications of classic statistical procedures to heavily skewed proxy records. Inspired by runoff proxies, we consider an idealized proxy characterized by a nonlinear, thresholded relationship with climate, and describe three approaches to using such a record to infer past climate: (i) applying standard methods commonly used in the paleoclimate literature, without considering the non-linearities inherent to the proxy record; (ii) applying a power transform prior to using these standard methods; (iii) constructing a Bayesian model to invert the mechanistic relationship between the climate and the proxy. We find that neglecting the skewness in the proxy leads to erroneous conclusions and often exaggerates changes in climate variability between different time intervals. In contrast, an explicit treatment of the skewness, using either power transforms or a Bayesian inversion of the mechanistic model for the proxy, yields significantly better estimates of past climate variations. We apply these insights in two paleoclimate settings: (1) a classical sedimentary record from Laguna Pallcacocha, Ecuador (Moy et al., 2002). Our results agree with the qualitative aspects of previous analyses of this record, but quantitative departures are evident and hold implications for how such records are interpreted, and compared to other proxy records. (2) a multiproxy reconstruction of temperature over the Common Era (Mann et al., 2009), where we find that about one third of the records display significant departures from normality. Accordingly, accounting for skewness in proxy predictors has a notable influence on both reconstructed global mean and spatial patterns of temperature change. Inferring climate variability from skewed proxy records thus requires cares, but can be done with relatively simple tools. References - Mann, M. E., Z. Zhang, S. Rutherford, R. S. Bradley, M. K. Hughes, D. Shindell, C. Ammann, G. Faluvegi, and F. Ni (2009), Global signatures and dynamical origins of the little ice age and medieval climate anomaly, Science, 326(5957), 1256-1260, doi:10.1126/science.1177303. - Moy, C., G. Seltzer, D. Rodbell, and D. Anderson (2002), Variability of El Niño/Southern Oscillation activ- ity at millennial timescales during the Holocene epoch, Nature, 420(6912), 162-165.

An application of the Health Action Process Approach model to oral hygiene behaviour and dental plaque in adolescents with fixed orthodontic appliances.

PubMed

Scheerman, Janneke F M; van Empelen, Pepijn; van Loveren, Cor; Pakpour, Amir H; van Meijel, Berno; Gholami, Maryam; Mierzaie, Zaher; van den Braak, Matheus C T; Verrips, Gijsbert H W

2017-11-01

The Health Action Process Approach (HAPA) model addresses health behaviours, but it has never been applied to model adolescents' oral hygiene behaviour during fixed orthodontic treatment. This study aimed to apply the HAPA model to explain adolescents' oral hygiene behaviour and dental plaque during orthodontic treatment with fixed appliances. In this cross-sectional study, 116 adolescents with fixed appliances from an orthodontic clinic situated in Almere (the Netherlands) completed a questionnaire assessing oral health behaviours and the psychosocial factors of the HAPA model. Linear regression analyses were performed to examine the factors associated with dental plaque, toothbrushing, and the use of a proxy brush. Stepwise regression analysis showed that lower amounts of plaque were significantly associated with higher frequency of the use of a proxy brush (R 2 = 45%), higher intention of the use of a proxy brush (R 2 = 5%), female gender (R 2 = 2%), and older age (R 2 = 2%). The multiple regression analyses revealed that higher action self-efficacy, intention, maintenance self-efficacy, and a higher education were significantly associated with the use of a proxy brush (R 2 = 45%). Decreased levels of dental plaque are mainly associated with increased use of a proxy brush that is subsequently associated with a higher intention and self-efficacy to use the proxy brush. © 2017 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Assessing the utility of elemental ratios as a paleotemperature proxy in shells of patelloid limpets

NASA Astrophysics Data System (ADS)

Graniero, Lauren; Surge, Donna; Gillikin, David

2015-04-01

Archaeological shell and fish middens are rich sources of paleoenvironmental proxy data. Carbonate hard part remains contained in such deposits have been used as archives of coastal marine climate and human-climate interactions. Oxygen isotope records from fast-growing limpet shells potentially capture summer and winter seasons, and thus, approach the full seasonal range of sea surface temperature (SST). Fast-growing shells are often short-lived, providing "snap-shots" of multi-year seasonal cycles. Patelloid limpet shells are common constituents in archaeological middens found along European, African, and South American coastlines. Oxygen isotope ratios of archaeological limpet shells from the genus, Patella, have been used to reconstruct seasonal SST and ocean circulation patterns during the Late Quaternary. Such studies depend on the ability to constrain the oxygen isotope ratio of seawater; therefore, alternative proxies are necessary for coastal localities where this is not possible. Elemental ratios (e.g., Sr/Ca, Mg/Ca) have been used as paleotemperature proxies in corals and foraminifera with varying degrees of success and appear problematic in bivalves. Here, we test whether such elemental ratios are useful as an alternative SST proxy in patelloid limpet shells.

Sleep-related crash characteristics: Implications for applying a fatigue definition to crash reports.

PubMed

Filtness, A J; Armstrong, K A; Watson, A; Smith, S S

2017-02-01

Sleep-related (SR) crashes are an endemic problem the world over. However, police officers report difficulties in identifying sleepiness as a crash contributing factor. One approach to improving the sensitivity of SR crash identification is by applying a proxy definition post hoc to crash reports. To identify the prominent characteristics of SR crashes and highlight the influence of proxy definitions, ten years of Queensland (Australia) police reports of crashes occurring in ≥100km/h speed zones were analysed. In Queensland, two approaches are routinely taken to identifying SR crashes. First, attending police officers identify crash causal factors; one possible option is 'fatigue/fell asleep'. Second, a proxy definition is applied to all crash reports. Those meeting the definition are considered SR and added to the police-reported SR crashes. Of the 65,204 vehicle operators involved in crashes 3449 were police-reported as SR. Analyses of these data found that male drivers aged 16-24 years within the first two years of unsupervised driving were most likely to have a SR crash. Collision with a stationary object was more likely in SR than in not-SR crashes. Using the proxy definition 9739 (14.9%) crashes were classified as SR. Using the proxy definition removes the findings that SR crashes are more likely to involve males and be of high severity. Additionally, proxy defined SR crashes are no less likely at intersections than not-SR crashes. When interpreting crash data it is important to understand the implications of SR identification because strategies aimed at reducing the road toll are informed by such data. Without the correct interpretation, funding could be misdirected. Improving sleepiness identification should be a priority in terms of both improvement to police and proxy reporting. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multi-timescale data assimilation for atmosphere–ocean state estimates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steiger, Nathan; Hakim, Gregory

2016-06-24

Paleoclimate proxy data span seasonal to millennial timescales, and Earth's climate system has both high- and low-frequency components. Yet it is currently unclear how best to incorporate multiple timescales of proxy data into a single reconstruction framework and to also capture both high- and low-frequency components of reconstructed variables. Here we present a data assimilation approach that can explicitly incorporate proxy data at arbitrary timescales. The principal advantage of using such an approach is that it allows much more proxy data to inform a climate reconstruction, though there can be additional benefits. Through a series of offline data-assimilation-based pseudoproxy experiments,more » we find that atmosphere–ocean states are most skillfully reconstructed by incorporating proxies across multiple timescales compared to using proxies at short (annual) or long (~ decadal) timescales alone. Additionally, reconstructions that incorporate long-timescale pseudoproxies improve the low-frequency components of the reconstructions relative to using only high-resolution pseudoproxies. We argue that this is because time averaging high-resolution observations improves their covariance relationship with the slowly varying components of the coupled-climate system, which the data assimilation algorithm can exploit. These results are consistent across the climate models considered, despite the model variables having very different spectral characteristics. Furthermore, our results also suggest that it may be possible to reconstruct features of the oceanic meridional overturning circulation based on atmospheric surface temperature proxies, though here we find such reconstructions lack spectral power over a broad range of frequencies.« less

Bidding Behavior in a Multi-attribute First-price Auction

DTIC Science & Technology

2010-01-01

of applying key features of the multi-unit auction to proxy buyer /seller marginal valuations of the attributes of a job. Two experiments were...compensation package show promise in ascertaining buyer /seller marginal valuations of a job. This research effort was supported by a grant from the...auctions observed in the goods market, as measured by maximizing consumer and producer surplus, are likely to have promising applications to labor markets

Prevalence of cardiovascular risk factors among Latin American adolescents: a multilevel analysis.

PubMed

de Moraes, A C F; Musso, C; Graffigna, M N; Soutelo, J; Migliano, M; Carvalho, H B; Berg, G

2014-03-01

High blood pressure (HBP) and obesity is a well-established major risk factor for stroke and coronary heart disease. However, the literatures are scarce about these informations in adolescents from low-and-middle income countries. This school-based survey was carried out among students from Maringá (Brazil) and Buenos Aires (Argentina) selected random sampling. We studied 991 Brazilian adolescents (54.5% girls) in the age range of 14-18 years. In Argentina, we studied 933 adolescents (45.9% female) in the age range of 11-17 years. The outcomes of this study are general obesity, abdominal obesity and HBP. The associated factors analysed were gender, age and health behaviours. The prevalence of obesity was 5.8% in Brazil and 2.8% in Argentina, the prevalence of abdominal obesity was 32.7% in Brazil and 11.1% in Argentina, the prevalence of HBP was 14.9% in Brazil and 13.5% in Argentina. The multilevel analysis showed that older adolescents (>14 years old) have a little likelihood of being overweight, whereas male adolescents are more likely to be obese and have HBP. The abdominal obesity in both indicators were not associated with the independent variables. The prevalence of cardiovascular risk factors is high in Latin American adolescents independent of each country, and was associated with male gender.

Analysis of the data on pregnancy and lactation provided by patient information leaflets of anti-rheumatic drugs in Argentina.

PubMed

Sabando, Miguel Ormaza; Saavedra, Maira Arias; Sequeira, Gabriel; Kerzberg, Eduardo

2018-04-01

To analyse the level of consistency and updating of the information on pregnancy and lactation provided by patient information leaflets (PILs) of the antirheumatic drugs approved in Argentina. Inconsistencies between the 2016 EULAR Task Force recommendations on the use of anti-rheumatic drugs during pregnancy and lactation and the information provided by PILs of the same drugs approved in Argentina were analysed along with inconsistencies within the PILs of different registered trademarks of these drugs. Eighty-eight PILs of 32 drugs were analysed. Out of the 88 PILs, 50% presented information inconsistencies as to pregnancy. Medications comprised in this group were: hydroxychloroquine, sulfasalazine, azathioprine, tacrolimus, cyclosporine, NSAIDs (during the first two trimesters), celecoxib, some glucocorticoids, colchicine, and some anti-TNF drugs (etanercept, adalimumab and infliximab) during part of the pregnancy. As for lactation, 56% had information inconsistencies. Medications encompassed in this group were: hydroxychloroquine, chloroquine, sulfasalazine, azathioprine, tacrolimus, cyclosporine, NSAIDs, celecoxib, meprednisone, prednisone, colchicine, and anti-TNF drugs. Out of 17 drugs that had more than one registered trademark, information inconsistencies on pregnancy were found in the PILs of sulfasalazine, diclofenac, ibuprofen and methylprednisolone. Concerning lactation, inconsistencies were present in the PILs of hydroxychloroquine, sulfasalazine, diclofenac, ibuprofen, meprednisone, and colchicine. At least half of the PILs of anti-rheumatic drugs analysed in this study had information inconsistencies on pregnancy and lactation. This is a serious state of affairs because the consensual decision-making process between patient and professional may be compromised, which, in turn, may give rise to medical-legal issues.

Seismically-induced soft-sediment deformation structures associated with the Magallanes-Fagnano Fault System (Isla Grande de Tierra del Fuego, Argentina)

NASA Astrophysics Data System (ADS)

Onorato, M. Romina; Perucca, Laura; Coronato, Andrea; Rabassa, Jorge; López, Ramiro

2016-10-01

In this paper, evidence of paleoearthquake-induced soft-sediment deformation structures associated with the Magallanes-Fagnano Fault System in the Isla Grande de Tierra del Fuego, southern Argentina, has been identified. Well-preserved soft-sediment deformation structures were found in a Holocene sequence of the Udaeta pond. These structures were analyzed in terms of their geometrical characteristics, deformation mechanism, driving force system and possible trigger agent. They were also grouped in different morphological types: sand dykes, convolute lamination, load structures and faulted soft-sediment deformation features. Udaeta, a small pond in Argentina Tierra del Fuego, is considered a Quaternary pull-apart basin related to the Magallanes-Fagnano Fault System. The recognition of these seismically-induced features is an essential tool for paleoseismic studies. Since the three main urban centers in the Tierra del Fuego province of Argentina (Ushuaia, Río Grande and Tolhuin) have undergone an explosive growth in recent years, the results of this study will hopefully contribute to future analyses of the seismic risk of the region.

Yellow fever vaccine-associated adverse events following extensive immunization in Argentina.

PubMed

Biscayart, Cristián; Carrega, María Eugenia Pérez; Sagradini, Sandra; Gentile, Angela; Stecher, Daniel; Orduna, Tomás; Bentancourt, Silvia; Jiménez, Salvador García; Flynn, Luis Pedro; Arce, Gabriel Pirán; Uboldi, María Andrea; Bugna, Laura; Morales, María Alejandra; Digilio, Clara; Fabbri, Cintia; Enría, Delia; Diosque, Máximo; Vizzotti, Carla

2014-03-05

As a consequence of YF outbreaks that hit Brazil, Argentina, and Paraguay in 2008-2009, a significant demand for YF vaccination was subsequently observed in Argentina, a country where the usual vaccine recommendations are restricted to provinces that border Brazil, Paraguay, and Bolivia. The goal of this paper is to describe the adverse events following immunization (AEFI) against YF in Argentina during the outbreak in the northeastern province of Misiones, which occurred from January 2008 to January 2009. During this time, a total of nine cases were reported, almost two million doses of vaccine were administered, and a total of 165 AEFI were reported from different provinces. Case study analyses were performed using two AEFI classifications. Forty-nine events were classified as related to the YF vaccine (24 serious and 1 fatal case), and 12 events were classified as inconclusive. As the use of the YF 17D vaccine can be a challenge to health systems of countries with different endemicity patterns, a careful clinical and epidemiological evaluation should be performed before its prescription to minimize serious adverse events. Copyright © 2014 Elsevier Ltd. All rights reserved.

Statistical analysis of iron geochemical data suggests limited late Proterozoic oxygenation

NASA Astrophysics Data System (ADS)

Sperling, Erik A.; Wolock, Charles J.; Morgan, Alex S.; Gill, Benjamin C.; Kunzmann, Marcus; Halverson, Galen P.; MacDonald, Francis A.; Knoll, Andrew H.; Johnston, David T.

2015-07-01

Sedimentary rocks deposited across the Proterozoic-Phanerozoic transition record extreme climate fluctuations, a potential rise in atmospheric oxygen or re-organization of the seafloor redox landscape, and the initial diversification of animals. It is widely assumed that the inferred redox change facilitated the observed trends in biodiversity. Establishing this palaeoenvironmental context, however, requires that changes in marine redox structure be tracked by means of geochemical proxies and translated into estimates of atmospheric oxygen. Iron-based proxies are among the most effective tools for tracking the redox chemistry of ancient oceans. These proxies are inherently local, but have global implications when analysed collectively and statistically. Here we analyse about 4,700 iron-speciation measurements from shales 2,300 to 360 million years old. Our statistical analyses suggest that subsurface water masses in mid-Proterozoic oceans were predominantly anoxic and ferruginous (depleted in dissolved oxygen and iron-bearing), but with a tendency towards euxinia (sulfide-bearing) that is not observed in the Neoproterozoic era. Analyses further indicate that early animals did not experience appreciable benthic sulfide stress. Finally, unlike proxies based on redox-sensitive trace-metal abundances, iron geochemical data do not show a statistically significant change in oxygen content through the Ediacaran and Cambrian periods, sharply constraining the magnitude of the end-Proterozoic oxygen increase. Indeed, this re-analysis of trace-metal data is consistent with oxygenation continuing well into the Palaeozoic era. Therefore, if changing redox conditions facilitated animal diversification, it did so through a limited rise in oxygen past critical functional and ecological thresholds, as is seen in modern oxygen minimum zone benthic animal communities.

Comment on "Advective transport in heterogeneous aquifers: Are proxy models predictive?" by A. Fiori, A. Zarlenga, H. Gotovac, I. Jankovic, E. Volpi, V. Cvetkovic, and G. Dagan

NASA Astrophysics Data System (ADS)

Neuman, Shlomo P.

2016-07-01

Fiori et al. (2015) examine the predictive capabilities of (among others) two "proxy" non-Fickian transport models, MRMT (Multi-Rate Mass Transfer) and CTRW (Continuous-Time Random Walk). In particular, they compare proxy model predictions of mean breakthrough curves (BTCs) at a sequence of control planes with near-ergodic BTCs generated through two- and three-dimensional simulations of nonreactive, mean-uniform advective transport in single realizations of stationary, randomly heterogeneous porous media. The authors find fitted proxy model parameters to be nonunique and devoid of clear physical meaning. This notwithstanding, they conclude optimistically that "i. Fitting the proxy models to match the BTC at [one control plane] automatically ensures prediction at downstream control planes [and thus] ii. … the measured BTC can be used directly for prediction, with no need to use models underlain by fitting." I show that (a) the authors' findings follow directly from (and thus confirm) theoretical considerations discussed earlier by Neuman and Tartakovsky (2009), which (b) additionally demonstrate that proxy models will lack similar predictive capabilities under more realistic, non-Markovian flow and transport conditions that prevail under flow through nonstationary (e.g., multiscale) media in the presence of boundaries and/or nonuniformly distributed sources, and/or when flow/transport are conditioned on measurements.

A Model for Describing, Analysing and Investigating Cultural Understanding in EFL Reading Settings

ERIC Educational Resources Information Center

Porto, Melina

2013-01-01

This article describes a model used to explore cultural understanding in English as a foreign language reading in a developing country, namely Argentina. The model is designed to investigate, analyse and describe EFL readers' processes of cultural understanding in a specific context. Cultural understanding in reading is typically investigated…

Patagonian and Antarctic dust as recorded in the sediments of Laguna Potrok Aike (Patagonia, Argentina)

NASA Astrophysics Data System (ADS)

Haberzettl, Torsten; Stopp, Annemarie; Lisé-Pronovost, Agathe; Gebhardt, Catalina; Ohlendorf, Christian; Zolitschka, Bernd; von Eynatten, Hilmar; Kleinhanns, Ilka; Pasado Science Team

2010-05-01

Although an increasing number of terrestrial paleoclimatic records from southern South America has been published during the last decade, these archives mostly cover the Lateglacial and/or the Holocene. Only little is known about the Patagonian climate before the Last Glacial Maximum. Here, we present a continuous, high-resolution magnetic susceptibility record for the past 48 ka from the maar lake Laguna Potrok Aike (51°58' S, 70°23' W, southern Patagonia, Argentina). Magnetic susceptibility serves as an excellent parameter for the parallelization of sediment cores all over Laguna Potrok Aike including sediment cores taken within the ICDP (International Continental Scientific Drilling Program) project PASADO (Potrok Aike maar lake Sediment Archive Drilling prOject). Additionally, magnetic susceptibility is assumed to be a proxy for dust deposition in this lake. Distinct similarities were found between the independently dated magnetic susceptibility record from Laguna Potrok Aike and the non-sea-salt calcium (nss-Ca) flux from the EPICA Dome C ice core record (75°06'S, 123°24'E) the latter being a proxy for mineral dust deposition in Antarctica [1]. Comparison of the two records and variations in grain size of the Laguna Potrok Aike sediment records indicate a relatively high aeolian activity in southern South America during the glacial period. During the Holocene climatic conditions driving sediment deposition seem to have been more variable and less dominated by wind compared to glacial times. Although the source of the dust found in Antarctic ice cores often has been attributed to Patagonia [2], we present the first evidence for contemporaneity of aeolian deposition in both the target area (Antarctica) and the major source area (Patagonia). Considering the similarities of the two records, magnetic susceptibility might yield the potential for chronological information: transfer of the ice core age model to a lacustrine sediment record. This would be important as additional time control for the recently recovered sediment record within the ICDP deep drilling project PASADO. To support this idea, we performed Sr/Nd-isotopic analyses on the assumed aeolian, well sorted fraction (63-200 µm) deposited in Laguna Potrok Aike during the last glaciation as well as on the <5 µm fraction which is commonly found as dust in Antarctica - both on the same samples. These results are compared to the Sr/Nd-isotopic signatures measured directly on dust from Antarctic ice cores [2]: the isotopic data field of sediments from Laguna Potrok Aike superposes a large part of isotopic data from Antarctic dust, although the 87Sr/86Sr-data seems to show a slight offset to lower values. In conclusion our analyses confirm previous studies that suggested southern South America to be the main source area of east Antarctic dust during glacial periods. However, this is the first evidence for a contemporaneous dust deposition pattern in Patagonia and Antarctica. References [1] R. Röthlisberger, R. Mulvaney, E.W. Wolff, M.A. Hutterli, M. Bigler, S. Sommer, J. Jouzel, Dust and sea salt variability in central East Antarctica (Dome C) over the last 45 kyrs and its implications for southern high-latitude climate, Geophysical Research Letters 29 (2002) doi:10.1029/2002GL015186. [2] B. Delmonte, I. Basile-Doelsch, J.R. Petit, V. Maggi, M. Revel-Rolland, A. Michard, E. Jagoutz, F. Grousset, Comparing the Epica and Vostok dust records during the last 220,000 years: stratigraphical correlation and provenance in glacial periods, Earth-Science Reviews 66 (2004) 63-87.

Potential for tree rings to reveal spatial patterns of past drought variability across western Australia

NASA Astrophysics Data System (ADS)

O'Donnell, Alison J.; Cook, Edward R.; Palmer, Jonathan G.; Turney, Chris S. M.; Grierson, Pauline F.

2018-02-01

Proxy records have provided major insights into the variability of past climates over long timescales. However, for much of the Southern Hemisphere, the ability to identify spatial patterns of past climatic variability is constrained by the sparse distribution of proxy records. This is particularly true for mainland Australia, where relatively few proxy records are located. Here, we (1) assess the potential to use existing proxy records in the Australasian region—starting with the only two multi-century tree-ring proxies from mainland Australia—to reveal spatial patterns of past hydroclimatic variability across the western third of the continent, and (2) identify strategic locations to target for the development of new proxy records. We show that the two existing tree-ring records allow robust reconstructions of past hydroclimatic variability over spatially broad areas (i.e. > 3° × 3°) in inland north- and south-western Australia. Our results reveal synchronous periods of drought and wet conditions between the inland northern and southern regions of western Australia as well as a generally anti-phase relationship with hydroclimate in eastern Australia over the last two centuries. The inclusion of 174 tree-ring proxy records from Tasmania, New Zealand and Indonesia and a coral record from Queensland did not improve the reconstruction potential over western Australia. However, our findings suggest that the addition of relatively few new proxy records from key locations in western Australia that currently have low reconstruction skill will enable the development of a comprehensive drought atlas for the region, and provide a critical link to the drought atlases of monsoonal Asia and eastern Australia and New Zealand.

Geochemical Ecology of a High Latitude Coral: Plesiastrea versipora a new Paleo-Environmental Archive

NASA Astrophysics Data System (ADS)

Burgess, S. N.; McCulloch, M. M.; Ward, T.

2005-12-01

Corals growing in high latitude waters in Southern Australia are considered to be sensitive to changes in climate, including seasonal fluctuations in sea surface temperature. The annual nature of density bands of Plesiastrea versipora were verified using U/Th ages derived from multi-collector ICP-MS analyses and the resulting extension rates varied from an average of 1.2 mm yr -1 to 9 mm yr -1 for different colonies ranging in age from 120 - 300 years, located within the same reef. High resolution laser-ablation ICP-MS analyses of established paleo-temperature proxies including B/Ca, Mg/Ca, Sr/Ca and U/Ca were obtained from several cores of P. versipora from Gulf St Vincent (34.5°S) and Spencer Gulf (35°S), South Australia. Elemental compositions were compared to in situ sea surface temperature (SST) and satellite (IGOSS) records, and demonstrate significant covariance between Ba/Ca and temperature. Barium may not have been recognised as a temperature proxy in previous studies due to the smaller temperature range for lower latitude environments (~ 5°C versus 12°C for this study) and other factors contributing to the Ba signal such as terrestrially-derived or upwelled sources. Other trace elements analysed gave an indication of both the nutrient availability (P and Mn) and terrestrially derived pollutants (V, Y, Mo, Sn and Pb) correlating strongly with luminescent bands. Several of the stronger luminescent bands coincide temporally with known oil spills at a nearby port refinery and research is ongoing to determine if this is the point source of pollution. These data taken together suggest that P. versipora can provide valuable paleoclimate information in high-latitude environments, recording large seasonal variation in both temperature and productivity regimes with high fidelity and may also be employed to reconstruct anthropogenic activity.

A Multidisciplinary Approach to Assessing the Causal Components of Climate Change

NASA Astrophysics Data System (ADS)

Gosnold, W. D.; Todhunter, P. E.; Dong, X.; Rundquist, B.; Majorowicz, J.; Blackwell, D. D.

2004-05-01

Separation of climate forcing by anthropogenic greenhouse gases from natural radiative climate forcing is difficult because the composite temperature signal in the meteorological and multi-proxy temperature records cannot be resolved directly into radiative forcing components. To address this problem, we have initiated a large-scale, multidisciplinary project to test coherence between ground surface temperatures (GST) reconstructed from borehole T-z profiles, surface air temperatures (SAT), soil temperatures, and solar radiation. Our hypothesis is that radiative heating and heat exchange between the ground and the air directly control the ground surface temperature. Consequently, borehole T-z measurements at multi-year intervals spanning time periods when solar radiation, soil and air temperatures have been recorded should enable comparison of the thermal energy stored in the ground to these quantities. If coherence between energy storage, solar radiation, GST, SAT and multi-proxy temperature data can be discerned for a one or two decade scale, synthesis of GST and multi-proxy data over the past several centuries may enable us to separately determine the anthropogenic and natural forcings of climate change. The data we are acquiring include: (1) New T-z measurements in boreholes previously used in paleoclimate and heat flow research in Canada and the United States from the 1970's to the present. (2) Meteorological data from the US Historical Climatology Network and the Automated Weather Data Network of the High Plains Regional Climate Center, and Environment Canada. (3) Direct and remotely sensed data on land use, environment, and soil properties at selected borehole and meteorological sites for the periods between borehole observations. The project addresses three related questions: What is the coherence between the GST, SAT, soil temperatures and solar radiation? Have microclimate changes at borehole sites and climate stations affected temperature trends? If good coherence is obtained, can the coherence between thermal energy stored in the ground and radiative forcing during the time between T-z measurements be extended several centuries into the past?

Participatory, Multi-Criteria Evaluation Methods as a Means to Increase the Legitimacy and Sustainability of Land Use Planning Processes. The Case of the Chaco Region in Salta, Argentina.

PubMed

Seghezzo, Lucas; Venencia, Cristian; Buliubasich, E Catalina; Iribarnegaray, Martín A; Volante, José N

2017-02-01

Conflicts over land use and ownership are common in South America and generate frequent confrontations among indigenous peoples, small-scale farmers, and large-scale agricultural producers. We argue in this paper that an accurate identification of these conflicts, together with a participatory evaluation of their importance, will increase the social legitimacy of land use planning processes, rendering decision-making more sustainable in the long term. We describe here a participatory, multi-criteria conflict assessment model developed to identify, locate, and categorize land tenure and use conflicts. The model was applied to the case of the "Chaco" region of the province of Salta, in northwestern Argentina. Basic geographic, cadastral, and social information needed to apply the model was made spatially explicit on a Geographic Information System. Results illustrate the contrasting perceptions of different stakeholders (government officials, social and environmental non-governmental organizations, large-scale agricultural producers, and scholars) on the intensity of land use conflicts in the study area. These results can help better understand and address land tenure conflicts in areas with different cultures and conflicting social and enviornmental interests.

Participatory, Multi-Criteria Evaluation Methods as a Means to Increase the Legitimacy and Sustainability of Land Use Planning Processes. The Case of the Chaco Region in Salta, Argentina

NASA Astrophysics Data System (ADS)

Seghezzo, Lucas; Venencia, Cristian; Buliubasich, E. Catalina; Iribarnegaray, Martín A.; Volante, José N.

2017-02-01

Conflicts over land use and ownership are common in South America and generate frequent confrontations among indigenous peoples, small-scale farmers, and large-scale agricultural producers. We argue in this paper that an accurate identification of these conflicts, together with a participatory evaluation of their importance, will increase the social legitimacy of land use planning processes, rendering decision-making more sustainable in the long term. We describe here a participatory, multi-criteria conflict assessment model developed to identify, locate, and categorize land tenure and use conflicts. The model was applied to the case of the "Chaco" region of the province of Salta, in northwestern Argentina. Basic geographic, cadastral, and social information needed to apply the model was made spatially explicit on a Geographic Information System. Results illustrate the contrasting perceptions of different stakeholders (government officials, social and environmental non-governmental organizations, large-scale agricultural producers, and scholars) on the intensity of land use conflicts in the study area. These results can help better understand and address land tenure conflicts in areas with different cultures and conflicting social and enviornmental interests.

Workers' Self-management, Recovered Companies and the Sociology of Work.

PubMed

Ozarow, Daniel; Croucher, Richard

2014-10-01

We analyse how far Argentina's worker-recovered companies (WRCs) have sustained themselves and their principles of equity and workers' self-management since becoming widespread following the country's 2001-2 economic crisis. Specialist Spanish-language sources, survey data and documents are analysed through four key sociological themes. We find that the number of WRCs has increased in Argentina, and that they represent a viable production model. Further, they have generally maintained their central principles and even flourished. This occurred despite the global economic crisis, legal and financial pressures to adopt capitalist practices and management structures, the risk of market absorption and state attempts to coopt, demobilise and depoliticise the movement. We argue that today they function as a much-needed international beacon of an alternative vision for labour and that integration of their experience has potential to revitalise the field.

Comparing ungulate dietary proxies using discriminant function analysis.

PubMed

Fraser, Danielle; Theodor, Jessica M

2011-12-01

A variety of tooth-wear and morphological dietary proxies have been proposed for ungulates. In turn, they have been applied to fossil specimens with the purpose of reconstructing the diets of extinct taxa. Although these dietary proxies have been used in isolation and in combination, a consistent set of statistical analyses has never been applied to all of the available datasets. The purpose of this study is to determine how well the most commonly used dietary proxies classify ungulates as browsers, grazers, and mixed feeders individually and in combination. Discriminant function analysis is applied to individual dietary proxies (hypsodonty, mesowear, microwear, and several cranial dietary proxies) and to combinations thereof to compare rates of successful dietary classification. In general, the tooth-wear dietary proxies (mesowear and microwear) perform better than morphological dietary proxies, though none are strong proxies in isolation. The success rates of the cranial dietary proxies are not increased substantially when ruminants and bovids are analyzed separately, and significance among the three dietary guilds is reduced when controlling for phylogenetic relatedness. The combination of hypsodonty, mesowear, and microwear is found to have a high rate of successful dietary classification, but a combination of all commonly used proxies increases the success rate to 100%. In most cases, mixed feeders bear the greatest resemblance to browsers suggesting that a morphology intermediate to browsers and grazers may represent a fitness valley resulting from the inability to exploit both browse and graze efficiently. These results are important for future paleoecological studies and should be used as a guide for determining which dietary proxies are appropriate to the research question. Copyright © 2011 Wiley-Liss, Inc.

Citizen cartography, strategies of resistance to established knowledge and collective forms of knowledge building.

PubMed

Sannazzaro, Jorgelina

2016-04-01

Cultivation of genetically modified soybeans with the use of herbicides is now becoming widespread in Argentina. This work addresses an emblematic case of knowledge articulation between experts, professionals and communities, namely, the case of an association of people affected by fumigation Grupos de Pueblos Fumigados (GPF). The GPF warns against agrochemical spraying in urban areas, and its activists collect and disseminate information about its impact with a view to banning the practice. Here, we apply Parthasarathy's framework, used to analyse the strategies employed by activists to break the expertise barrier, to the case of the GPF, adding a new category to her original four strategies. There is an institutionalizing potential in these social and environmental movements, many of which are organized in the form of Civic Assemblies. The composition of the assemblies reflects a heterogeneous and multi-sectorial character; they articulate a new kind of knowledge that can be an appropriate interlocutor for traditional expert knowledge. © The Author(s) 2014.

Reconstructing Holocene glacier activity at Langfjordjøkelen, Arctic Norway, using multi-proxy fingerprinting of distal glacier-fed lake sediments

NASA Astrophysics Data System (ADS)

Wittmeier, Hella E.; Bakke, Jostein; Vasskog, Kristian; Trachsel, Mathias

2015-04-01

Late Glacial and Holocene glacier fluctuations are important indicators of climate variability in the northern polar region and contain knowledge vital to understanding and predicting present and future climate changes. However, there still is a lack of robustly dated terrestrial climate records from Arctic Norway. Here, we present a high-resolution relative glacier activity record covering the past ∼10,000 cal. a BP from the northern outlet of the Langfjordjøkelen ice cap in Arctic Norway. This record is reconstructed from detailed geomorphic mapping, multi-proxy sedimentary fingerprinting and analyses of distal glacier-fed lake sediments. We used Principal Component Analysis to characterize sediments of glacial origin and trace them in a chain of downstream lakes. Of the variability in the sediment record of the uppermost Lake Jøkelvatnet, 73% can be explained by the first Principal Component axis and tied directly to upstream glacier erosion, whereas the glacial signal becomes weaker in the more distal Lakes Store Rundvatnet and Storvatnet. Magnetic susceptibility and titanium count rates were found to be the most suitable indicators of Holocene glacier activity in the distal glacier-fed lakes. The complete deglaciation of the valley of Sør-Tverrfjorddalen occurred ∼10,000 cal. a BP, followed by a reduced or absent glacier during the Holocene Thermal Optimum. The Langfjordjøkelen ice cap reformed with the onset of the Neoglacial ∼4100 cal. a BP, and the gradually increasing glacier activity culminated at the end of the Little Ice Age in the early 20th century. Over the past 2000 cal. a BP, the record reflects frequent high-amplitude glacier fluctuations. Periods of reduced glacier activity were centered around 1880, 1600, 1250 and 950 cal. a BP, while intervals of increased glacier activity occurred around 1680, 1090, 440 and 25 cal. a BP. The large-scale Holocene glacier activity of the Langfjordjøkelen ice cap is consistent with regional temperature proxy reconstructions and glacier variability across Norway. Long-term changes in the extent of the northern outlet of the Langfjordjøkelen ice cap largely followed trends in regional summer temperatures, whereas winter season atmospheric variability may have triggered decadal-scale glacial fluctuations and generally affected the amplitude of glacier events.

[More than a century of international immigration into Argentina].

PubMed

Celton, D E

1995-01-01

"From the second half of the 19th century, Argentina was, along with the United States and Brazil, one of the main destinations that attracted European emigration to America.... The arrival of more that six million people between 1869 and 1930 resulted in radical changes in the socioeconomic structure of the country. After the crisis of the 1930s the impact of a development plan based on the export of agricultural products waned and the economic growth accompanied with political instability generated a slowing decline of migratory flows, despite a new wave between 1945 and 1952. The decrease of international migration comes along with an important change in the composition by places of origin.... The article analyses the successive migratory policies of Argentina's government as well as the migrants' spatial distribution and their incorporation in the labor market." (SUMMARY IN ENG AND SPA) excerpt

Current status and perspectives of the development of dental research in biological anthropology of Argentina: introduction and conclusions of the symposium.

PubMed

Luna, Leandro H; Bernal, Valeria

2011-10-01

This paper describes and discusses the research in the field of dental anthropology in Argentina. It has been presented at the symposium entitled "The development of dental research in Argentine Biological Anthropology: current status and perspectives", coordinated by the authors at the IX National Meeting of Biological Anthropology of Argentina, Puerto Madryn, 20th-23rd October 2009. The aim of the symposium was to present new results and future prospects of this discipline in the country and to create a forum for discussion of current research within this field. Six contributions that focused on the study of teeth from different perspectives and analysed bioarchaeological samples from different areas of Argentina (Central Highlands, Pampa and Patagonia) were presented. After the presentations, a discussion about the state of the art of dental research in the country was generated, in which the need for the generation of methodological consensus on the criteria for the evaluation of the variables considered was stated, so that research conducted in different areas can be compared. In short, the contributions of this symposium provide insights into the diversity of dental anthropology in contemporary Argentina and the potential of these types of studies to gain important information about biological and cultural aspects of the native populations in the country. Copyright © 2011 Elsevier GmbH. All rights reserved.

At the Feet of the Fortress: Analysis of Inka Period (ca. AD 1430-1536) Archaeofaunal Assemblages from Residential Unit 1 (RU1), Pucara de Tilcara (Jujuy, Argentina)

PubMed Central

2016-01-01

This paper reports the results of a zooarchaeological analysis conducted on the occupation layer of a compound structure (Residential Unit 1) of the Pucara de Tilcara archaeological site (Jujuy Province, northwestern Argentina). Its occupation span extends between the 13th and 15th centuries AD, but evidence diagnostic of the Inka Period (AD 1430–1536) is predominant. Residential Unit 1 was a house-workshop that hosted specialized crafts like metallurgy and lapidary during the Inka Period. It was proposed in previous works that artisans living at Pucara de Tilcara were provisioned with agropastoral products by the Inka administration. This paper aims to test that hypothesis against the zooarchaeological evidence of Residential Unit 1. Three variables were used as proxies for state-sponsored distribution: taxonomic diversity (family and species ranks), and skeletal and age profiles of the predominant zoological family (Camelidae) in the assemblage. The results show a high degree of continuity with the regional record, characterized by a herding-hunting strategy focused on domestic and wild species of Camelidae and a mixed mortality pattern. The skeletal profile shows a strong and negative correlation with the desiccation potential of elements, which could be indicative of local production of chalona. Overall, faunal evidence does not show any sign of centralized distribution. PMID:27732648

The last Deglaciation in the Mediterranean region: a multi-archives synthesis

NASA Astrophysics Data System (ADS)

Bazin, Lucie; Siani, Giuseppe; Landais, Amaelle; Bassinot, Frank; Genty, Dominique; Govin, Aline; Michel, Elisabeth; Nomade, Sebastien; Waelbroeck, Claire

2016-04-01

Multiple proxies record past climatic changes in different climate archives. These proxies are influenced by different component of the climate system and bring complementary information on past climate variability. The major limitation when combining proxies from different archives comes from the coherency of their chronologies. Indeed, each climate archives possess their own dating methods, not necessarily coherent with each other's. Consequently, when we want to assess the latitudinal changes and mechanisms behind a climate event, we often have to rely on assumptions of synchronisation between the different archives, such as synchronous temperature changes during warming events (Austin and Hibbert 2010). Recently, a dating method originally developed to produce coherent chronologies for ice cores (Datice,Lemieux-Dudon et al., 2010) has been adapted in order to integrate different climate archives (ice cores, sediment cores and speleothems (Lemieux-Dudon et al., 2015, Bazin et al., in prep)). In this presentation we present the validation of this multi-archives dating tool with a first application covering the last Deglaciation in the Mediterranean region. For this experiment, we consider the records from Monticchio, the MD90-917, Tenaghi Philippon and Lake Orhid sediment cores as well as continuous speleothems from Sofular, Soreq and La Mine caves. Using the Datice dating tool, and with the identification of common tephra layers between the cores considered, we are able to produce a multi-archives coherent chronology for this region, independently of any climatic assumption. Using this common chronological framework, we show that the usual climatic synchronisation assumptions are not valid over this region for the last glacial-interglacial transition. Finally, we compare our coherent Mediterranean chronology with Greenland ice core records in order to discuss the sequence of events of the last Deglaciation between these two regions.

Extreme flood event reconstruction spanning the last century in the El Bibane Lagoon (southeastern Tunisia): a multi-proxy approach

NASA Astrophysics Data System (ADS)

Affouri, Aida; Dezileau, Laurent; Kallel, Nejib

2017-06-01

Climate models project that rising atmospheric carbon dioxide concentrations will increase the frequency and the severity of some extreme weather events. The flood events represent a major risk for populations and infrastructures settled on coastal lowlands. Recent studies of lagoon sediments have enhanced our knowledge on extreme hydrological events such as palaeo-storms and on their relation with climate change over the last millennium. However, few studies have been undertaken to reconstruct past flood events from lagoon sediments. Here, the past flood activity was investigated using a multi-proxy approach combining sedimentological and geochemical analysis of surfaces sediments from a southeastern Tunisian catchment in order to trace the origin of sediment deposits in the El Bibane Lagoon. Three sediment sources were identified: marine, fluvial and aeolian. When applying this multi-proxy approach on core BL12-10, recovered from the El Bibane Lagoon, we can see that finer material, a high content of the clay and silt, and a high content of the elemental ratios (Fe / Ca and Ti / Ca) characterise the sedimentological signature of the palaeo-flood levels identified in the lagoonal sequence. For the last century, which is the period covered by the BL12-10 short core, three palaeo-flood events were identified. The age of these flood events have been determined by 210Pb and 137Cs chronology and give ages of AD 1995 ± 6, 1970 ± 9 and 1945 ± 9. These results show a good temporal correlation with historical flood events recorded in southern Tunisia in the last century (AD 1932, 1969, 1979 and 1995). Our finding suggests that reconstruction of the history of the hydrological extreme events during the upper Holocene is possible in this location through the use of the sedimentary archives.

Environmental controls for the precipitation of different fibrous calcite cement fabrics

NASA Astrophysics Data System (ADS)

Ritter, Ann-Christine; Wiethoff, Felix; Neuser, Rolf D.; Richter, Detlev K.; Immenhauser, Adrian

2016-04-01

Abiogenic calcite cements are widely used as climate archives. They can yield information on environmental change and climate dynamics at the time when the sediment was lithified in a (marine) diagenetic environment. Radiaxial-fibrous (RFC) and fascicular-optic fibrous (FOFC) calcite cements are two very common and similar pore-filling cement fabrics in Palaeozoic and Mesozoic carbonate rocks (Richter et al., 2011) and in Holocene Mg-calcitic speleothems (Richter et al., 2015). Both fabrics are characterised by distinct crystallographic properties. Current research has shown that these fabrics are often underexplored and that a careful combination of conservative and innovative proxies allows for a better applicability of these carbonate archives to paleoenvironmental reconstructions (Ritter et al., 2015). A main uncertainty in this context is that it is still poorly understood which parameters lead to the formation of either RFC or FOFC and if differential crystallographic parameters affect proxy data from these fabrics. This study aims at a better understanding of the environmental factors that may control either RFC or FOFC precipitation. Therefore, suitable samples (a stalagmite and a Triassic marine cement succession), each with clearly differentiable layers of RFC and FOFC, were identified and analysed in high detail using a multi-proxy approach. Detailed thin section and cathodoluminescence analysis of the samples allowed for a precise identification of layers consisting solely of either RFC or FOFC. Isotopic (δ13C, δ18O) as well as trace elemental compositions have been determined and the comparison of data obtained from these different carbonate archives sheds light on changes in environmental parameters during RFC or FOFC precipitation. References: Richter, D.K., et al., 2011. Radiaxial-fibrous calcites: A new look at an old problem. Sedimentary Geology, 239, 26-36 Richter, D.K., et al., 2015. Radiaxial-fibrous and fascicular-optic Mg-calcitic cave cements: a characterization usig electron backscattered diffraction (EBSD). International Journal of Speleology, 44, 91-98 Ritter, A.-C., et al., 2015. Application of redox sensitive proxies and carbonate clumped isotopes to Mesozoic and Palaeozoic radiaxial fibrous calcite cements. Chemical Geology, 417, 306-321

Inter-comparison of boron concentration measurements at INFN-University of Pavia (Italy) and CNEA (Argentina).

PubMed

Portu, Agustina; Postuma, Ian; Gadan, Mario Alberto; Saint Martin, Gisela; Olivera, María Silvina; Altieri, Saverio; Protti, Nicoletta; Bortolussi, Silva

2015-11-01

An inter-comparison of three boron determination techniques was carried out between laboratories from INFN-University of Pavia (Italy) and CNEA (Argentina): alpha spectrometry (alpha-spect), neutron capture radiography (NCR) and quantitative autoradiography (QTA). Samples of different nature were analysed: liquid standards, liver homogenates and tissue samples from different treatment protocols. The techniques showed a good agreement in a concentration range of interest in BNCT (1-100ppm), thus demonstrating their applicability as precise methods to quantify boron and determine its distribution in tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

Morphological and Genetic Analyses of the Invasive Forest Pathogen Phytophthora austrocedri Reveal that Two Clonal Lineages Colonized Britain and Argentina from a Common Ancestral Population.

PubMed

Henricot, Béatrice; Pérez-Sierra, Ana; Armstrong, April C; Sharp, Paul M; Green, Sarah

2017-12-01

Phytophthora austrocedri is causing widespread mortality of Austrocedrus chilensis in Argentina and Juniperus communis in Britain. The pathogen has also been isolated from J. horizontalis in Germany. Isolates from Britain, Argentina, and Germany are homothallic, with no clear differences in the dimensions of sporangia, oogonia, or oospores. Argentinian and German isolates grew faster than British isolates across a range of media and had a higher temperature tolerance, although most isolates, regardless of origin, grew best at 15°C and all isolates were killed at 25°C. Argentinian and British isolates caused lesions when inoculated onto both A. chilensis and J. communis; however, the Argentinian isolate caused longer lesions on A. chilensis than on J. communis and vice versa for the British isolate. Genetic analyses of nuclear and mitochondrial loci showed that all British isolates are identical. Argentinian isolates and the German isolate are also identical but differ from the British isolates. Single-nucleotide polymorphisms are shared between the British and Argentinian isolates. We concluded that British isolates and Argentinian isolates conform to two distinct clonal lineages of P. austrocedri founded from the same as-yet-unidentified source population. These lineages should be recognized and treated as separate risks by international plant health legislation.

Late Holocene monsoon climate as evidenced by proxy records from a lacustrine sediment sequence in western Guangdong, South China

NASA Astrophysics Data System (ADS)

Zhong, Wei; Cao, jiayuan; Xue, Jibin; Ouyang, Jun; Tang, Xiaohong; Yin, Huanling; Liao, Congyun; Long, Kun

2014-02-01

The study of a 300-cm-thick exposed lacustrine sediment section in the Hedong village in Zhaoqing area which is located in sub-tropical west Guangdong Province in South China, demonstrates that the lacustrine sedimentary sequence possibly contains evidence for exploring variation of Asian monsoon climate. Multi-proxy records, including the humification intensity, total organic carbon, and grain size fractions, reveal a general trend towards dry and cold conditions in the late Holocene that this is because of a decrease in solar insolation on an orbital scale. Three intensified Asian summer monsoon (ASM) intervals (˜3300-3000 cal yr BP, ˜2600-1600 cal yr BP, and ˜900-600 cal yr BP), and three weakened ASM intervals (˜4000-3300 cal yr BP, ˜3000-2600 cal yr BP, and ˜1600-900 cal yr BP) are identified. Our humification record (HDcal) shows a good correlation on multi-centennial scale with the tree ring Δ14C record, a proxy of solar activity. A spectral analysis of HDcal reveals four significant cycles, i.e., ˜1250 yr, 300 yr, 110 yr, and 70 yr, and most of these cycles are related to the solar activity. Our findings indicate that solar output and oceanic-atmospheric circulation probably have influenced the late Holocene climate variability in the study region.

A multi-proxy analysis of Late Quaternary ocean and climate variability for the Maldives, Inner Sea

NASA Astrophysics Data System (ADS)

Bunzel, Dorothea; Schmiedl, Gerhard; Lindhorst, Sebastian; Mackensen, Andreas; Reolid, Jesús; Romahn, Sarah; Betzler, Christian

2017-12-01

As a natural sediment trap, the marine sediments of the sheltered central part of the Maldives Inner Sea represent an exceptional archive for paleoenvironmental and climate changes in the equatorial Indian Ocean. To evaluate the complex interplay between high-latitude and monsoonal climate variability, related dust fluxes, and regional oceanographic responses, we focused on Fe / Al, Ti / Al and Si / Ca ratios as proxies for terrigenous sediment delivery and total organic carbon (TOC) and Br XRF counts as proxies for marine productivity. Benthic foraminiferal fauna distributions, grain size and stable δ18O and δ13C data were used for evaluating changes in the benthic ecosystem and changes in the intermediate water circulation, bottom water current velocity and oxygenation. Our multi-proxy data record reveals an enhanced dust supply during the glacial intervals, causing elevated Fe / Al and Si / Ca ratios, an overall coarsening of the sediment and an increasing amount of agglutinated benthic foraminifera. The enhanced dust fluxes can be attributed to higher dust availability in the Asian desert and loess areas and its transport by intensified winter monsoon winds during glacial conditions. These combined effects of wind-induced mixing of surface waters and dust fertilization during the cold phases resulted in an increased surface water productivity and related organic carbon fluxes. Thus, the development of highly diverse benthic foraminiferal faunas with certain detritus and suspension feeders was fostered. The difference in the δ13C signal between epifaunal and deep infaunal benthic foraminifera reveals intermediate water oxygen concentrations between approximately 40 and 100 µmol kg-1 during this time. The precessional fluctuation pattern of oxygen changes resembles that from the deep Arabian Sea, suggesting an expansion of the oxygen minimum zone (OMZ) from the Arabian Sea into the tropical Indian Ocean with a probable regional signal of strengthened winter-monsoon-induced organic matter fluxes and oxygen consumption further controlled by the varying inflow intensity of the Antarctic Intermediate Water (AAIW). In addition, the bottom water oxygenation pattern of the Maldives Inner Sea reveals a long phase of reduced ventilation during the last glacial period. This process is likely linked to the combined effects of generally enhanced oxygen consumption rates during high-productivity phases, reduced AAIW production and the restriction of upper bathyal environments in the Inner Sea during sea-level lowstands. Thus, our multi-proxy record reflects a close linkage between the Indian monsoon oscillation, intermediate water circulation, productivity and sea-level changes on orbital timescale.

Imprint of the Atlantic Multidecadal Oscillation on Tree-Ring Widths in Northeastern Asia since 1568

PubMed Central

Wang, Xiaochun; Brown, Peter M.; Zhang, Yanni; Song, Laiping

2011-01-01

We present a new tree-ring reconstruction of the Atlantic Multidecadal Oscillation (AMO) spanning 1568–2007 CE from northeast Asia. Comparison of the instrumental AMO index, an existing tree-ring based AMO reconstruction, and this new record show strongly similar annual to multidecadal patterns of variation over the last 440 years. Warm phases of the AMO are related to increases in growth of Scots pine trees and moisture availability in northeast China and central eastern Siberia. Multi-tape method (MTM) and cross-wavelet analyses indicate that robust multidecadal (∼64–128 years) variability is present throughout the new proxy record. Our results have important implications concerning the influence of North Atlantic sea surface temperatures on East Asian climate, and provide support for the possibility of an AMO signature on global multidecadal climate variability. PMID:21818380

Constant Flux Proxies and Pleistocene Sediment Accumulation Rates on the Juan de Fuca Ridge in the Northeast Pacific

NASA Astrophysics Data System (ADS)

Middleton, J. L.; Mukhopadhyay, S.; Langmuir, C. H.; Costa, K.; McManus, J. F.; d'Almeida, M.; Huybers, P. J.; Winckler, G.

2016-12-01

Mass accumulation rates of marine sediments are often employed to constrain deposition rates of important proxies such as terrigenous dust, carbonate, and biogenic opal to quantitatively examine variations in continental aridity, atmospheric transport, and biologic productivity across changing climatic conditions. However, deposition rates that are estimated using traditional mass accumulation rates calculated from sediment core age models can be subject to bias from lateral sediment transport and limited age model resolution. Constant flux proxies, such as extraterrestrial helium-3 (3HeET) and excess thorium-230 (230ThXS), can be used to calculate vertical sediment accumulation rates that are independent of age model uncertainties and the effects of lateral sediment transport. While a short half-life limits analyses of 230ThXS to the past 500 ka, 3HeET is stable and could be used to constrain sedimentary fluxes during much of the Cenozoic. Despite the vast paleoceanographic potential of constant flux proxies, few studies have directly compared the behavior of 230ThXS and 3HeET using measurements from the same samples. Sediment grain size fractionation and local scavenging effects may differentially bias one or both proxy systems and complicate the interpretation of 230ThXS or 3HeET data. We will present a new record of vertical sediment accumulation rates spanning the past 600 ka in the Northeast Pacific constrained using analyses of both 3HeET and 230ThXS in two sediment cores from cruise AT26-19 on the Juan de Fuca Ridge. Such a record allows for intercomparison of both constant flux proxies in the mid-ocean ridge environment and examination of sedimentary behavior across multiple glacial cycles. The 230ThXS-derived accumulation rates typically range from 0.5 to 2 g cm-2 ka-1 over the past 450 ka, with periods of maximum deposition coinciding with glacial maxima. Preliminary results of samples analyzed with both 3HeET and 230ThXS indicate relative consistency between vertical sediment accumulation rates computed from each proxy and encourage the use of these constant flux proxies in other sedimentary records.

Sao Paulo Lightning Mapping Array (SP-LMA): Network Assessment and Analyses for Intercomparison Studies and GOES-R Proxy Activities

NASA Technical Reports Server (NTRS)

Blakeslee, R. J.; Bailey, J. C.; Carey, L. D.; Goodman, S. J.; Rudlosky, S. D.; Albrecht, R.; Morales, C. A.; Anselmo, E. M.; Neves, J. R.

2013-01-01

A 12 station Lightning Mapping Array (LMA) network was deployed during October 2011in the vicinity of São Paulo, Brazil (SP-LMA) to contribute total lightning measurements to an international field campaign [CHUVA - Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)]. The SP-LMA was operational from November 2011 through March 2012. Sensor spacing was on the order of 15-30 km, with a network diameter on the order of 40-50km. The SP-LMA provides good 3-D lightning mapping out to150 km from the network center, with 2-D coverage considerably farther. In addition to supporting CHUVA science/mission objectives, the SP-LMA is supporting the generation of unique proxy data for the Geostationary Lightning Mapper (GLM) and Advanced Baseline Imager (ABI), on NOAA's Geostationary Operational Environmental Satellite-R (GOES-R: scheduled for a 2015 launch). These proxy data will be used to develop and validate operational algorithms so that they will be ready to use on "day1" following the GOES-R launch. The SP-LMA data also will be intercompared with lightning observations from other deployed lightning networks to advance our understanding of the capabilities/contributions of each of these networks toward GLM proxy and validation activities. This paper addresses the network assessment and analyses for intercomparison studies and GOES-R proxy activities

Lateglacial and Holocene climatic changes in south-eastern Patagonia inferred from carbonate isotope records of Laguna Potrok Aike (Argentina)

NASA Astrophysics Data System (ADS)

Oehlerich, M.; Mayr, C.; Gussone, N.; Hahn, A.; Hölzl, S.; Lücke, A.; Ohlendorf, C.; Rummel, S.; Teichert, B. M. A.; Zolitschka, B.

2015-04-01

First results of strontium, calcium, carbon and oxygen isotope analyses of bulk carbonates from a 106 m long sediment record of Laguna Potrok Aike, located in southern Patagonia are presented. Morphological and isotopic investigations of μm-sized carbonate crystals in the sediment reveal an endogenic origin for the entire Holocene. During this time period the calcium carbonate record of Laguna Potrok Aike turned out to be most likely ikaite-derived. As ikaite precipitation in nature has only been observed in a narrow temperature window between 0 and 7 °C, the respective carbonate oxygen isotope ratios serve as a proxy of hydrological variations rather than of palaeotemperatures. We suggest that oxygen isotope ratios are sensitive to changes of the lake water balance induced by intensity variations of the Southern Hemisphere Westerlies and discuss the role of this wind belt as a driver for climate change in southern South America. In combination with other proxy records the evolution of westerly wind intensities is reconstructed. Our data suggest that weak SHW prevailed during the Lateglacial and the early Holocene, interrupted by an interval with strengthened Westerlies between 13.4 and 11.3 ka cal BP. Wind strength increased at 9.2 ka cal BP and significantly intensified until 7.0 ka cal BP. Subsequently, the wind intensity diminished and stabilised to conditions similar to present day after a period of reduced evaporation during the "Little Ice Age". Strontium isotopes (87Sr/86Sr ratio) were identified as a potential lake-level indicator and point to a lowering from overflow conditions during the Glacial (∼17 ka cal BP) to lowest lake levels around 8 ka cal BP. Thereafter the strontium isotope curve resembles the lake-level curve which is stepwise rising until the "Little Ice Age". The variability of the Ca isotope composition of the sediment reflects changes in the Ca budget of the lake, indicating higher degrees of Ca utilisation during the period with lowest lake level.

Echinococcus oligarthrus in the subtropical region of Argentina: First integration of morphological and molecular analyses determines two distinct populations.

PubMed

Arrabal, Juan Pablo; Avila, Hector Gabriel; Rivero, Maria Romina; Camicia, Federico; Salas, Martin Miguel; Costa, Sebastián A; Nocera, Carlos G; Rosenzvit, Mara C; Kamenetzky, Laura

2017-06-15

Echinococcosis is a parasitic zoonosis that is considered as a neglected disease by the World Health Organization. The species Echinococcus oligarthrus is one of the causative agents of Neotropical echinococcosis, which is a poorly understood disease that requires a complex medical examination, may threaten human life, and is frequently associated with a low socioeconomic status. Morphological and genetic diversity in E. oligarthrus remains unknown. The aim of this work is to identify and characterize E. oligarthrus infections in sylvatic animals from the Upper Paraná Atlantic Forest in the province of Misiones, Argentina, by following an integrative approach that links morphological, genetic and ecological aspects. This study demonstrates, for the first time, one of the complete life cycles of E. oligarthrus in an important ecoregion. The Upper Paraná Atlantic Forest constitutes the largest remnant continuous forest of the Atlantic Forest, representing 7% of the world's biodiversity. This is the first molecular determination of E. oligarthrus in Argentina. In addition, the agouti (Dasyprocta azarae), the ocelot (Leopardus pardalis) and the puma (Puma concolor) were identified as sylvatic hosts of Neotropical echinococcosis caused by E. oligarthrus. Mitochondrial and nuclear molecular marker analyses showed a high genetic diversity in E. oligarthrus. Moreover, the genetic distance found among E. oligarthrus isolates is higher than the one observed among Echinococcus granulosus genotypes, which clearly indicates that there are at least two different E. oligarthrus populations in Argentina. This study provides valuable information to understand the underlying conditions that favour the maintenance of E. oligarthrus in sylvatic cycles and to evaluate its zoonotic significance for devising preventive measures for human and animal wellbeing. Copyright © 2017 Elsevier B.V. All rights reserved.

One thousand years of fires: Integrating proxy and model data

USGS Publications Warehouse

Kehrwald, Natalie; Aleman, Julie C.; Coughlan, Michael; Courtney Mustaphi, Colin J.; Githumbi, Esther N.; Magi, Brian I.; Marlon, Jennifer R.; Power, Mitchell J.

2016-01-01

The expected increase in fire activity in the upcoming decades has led to a surge in research trying to understand their causes, the factors that may have influenced similar times of fire activity in the past, and the implications of such fire activity in the future. Multiple types of complementary data provide information on the impacts of current fires and the extent of past fires. The wide array of data encompasses different spatial and temporal resolutions (Figure 1) and includes fire proxy information such as charcoal and tree ring fire scars, observational records, satellite products, modern emissions data, fire models within global land cover and vegetation models, and sociodemographic data for modeling past human land use and ignition frequency. Any single data type is more powerful when combined with another source of information. Merging model and proxy data enables analyses of how fire activity modifies vegetation distribution, air and water quality, and proximity to cities; these analyses in turn support land management decisions relating to conservation and development.

Inter-rater agreement of the Quality of Life-Alzheimer's Disease (QoL-AD) self-rating and proxy rating scale: secondary analysis of RightTimePlaceCare data.

PubMed

Römhild, Josephine; Fleischer, Steffen; Meyer, Gabriele; Stephan, Astrid; Zwakhalen, Sandra; Leino-Kilpi, Helena; Zabalegui, Adelaida; Saks, Kai; Soto-Martin, Maria; Sutcliffe, Caroline; Rahm Hallberg, Ingalill; Berg, Almuth

2018-06-28

To assess the quality of life of people with dementia, measures are required for self-rating by the person with dementia, and for proxy rating by others. The Quality of Life in Alzheimer's Disease scale (QoL-AD) is available in two versions, QoL-AD-SR (self-rating) and QoL-AD-PR (proxy rating). The aim of our study was to analyse the inter-rater agreement between self- and proxy ratings, in terms of both the total score and the items, including an analysis specific to care setting, and to identify factors associated with this agreement. Cross-sectional QoL-AD data from the 7th Framework European RightTimePlaceCare study were analysed. A total of 1330 cases were included: n = 854 receiving home care and n = 476 receiving institutional long-term nursing care. The proxy raters were informal carers (home care) and best-informed professional carers (institutional long-term nursing care). Inter-rater agreement was investigated using Bland-Altman plots for the QoL-AD total score and by weighted kappa statistics for single items. Associations were investigated by regression analysis. The overall QoL-AD assessment of those with dementia revealed a mean value of 33.2 points, and the proxy ratings revealed a mean value of 29.8 points. The Bland-Altman plots revealed a poor agreement between self- and proxy ratings for the overall sample and for both care settings. With one exception (item 'Marriage' weighted kappa 0.26), the weighted kappa values for the single QoL-AD items were below 0.20, indicating poor agreement. Home care setting, dementia-related behavioural and psychological symptoms, and the functional status of the person with dementia, along with the caregiver burden, were associated with the level of agreement. Only the home care setting was associated with an increase larger than the predefined acceptable difference between self- and proxy ratings. Proxy quality of life ratings from professional and informal carers appear to be lower than the self-ratings of those with dementia. QoL-AD-SR and QoL-AD-PR are therefore not interchangeable, as the inter-rater agreement differs distinctly. Thus, a proxy rating should be judged as a complementary perspective for a self-assessment of quality of life by those with dementia, rather than as a valid substitute.

Recalibrating the Ginkgo Stomatal Index Proxy for Past CO2 with Herbarium Specimens

NASA Astrophysics Data System (ADS)

Conde, G. D.; Retallack, G.

2015-12-01

The stomatal index of plant cuticles is inversely related to atmospheric CO2 concentrations, as calibrated from greenhouse experiments and herbarium specimens. Such calibration data for Ginkgo biloba are available for the ongoing rise in atmospheric CO2 and for high levels of CO2 anticipated in the future, but lacking for low CO2 levels of preindustrial and glacial ages. The oldest modern specimen that we have been able to obtain consists of leaf fragments collected in 1829 and provided by Arne Anderberg from the Swedish Natural History Museum. The specimen was labeled "Argentina", but also "Hortus Botanicus Augustinus", a garden founded in 1638 in Amsterdam, Netherlands. Ginkgo has a very thin cuticle that is difficult to prepare, but images very similar to cuticular preparation can be obtained by backscatter SEM imagery. We also obtained secondary SEM images of the same areas and counted 13 images with 6,184 cells from five leaf fragments. Our analyses yield a stomatal index of 10.9 ± 0.9 % for an atmospheric CO2 of 286 ppm, as determined by ice core data from Ciais and Sabine for IPCC-2013. This value is lower than from previous calibration curves for this level of CO2 and changes their curvature. With additional late nineteenth, twentieth and twenty-first century leaves, we can improve both the precision and lower limits of the transfer function for atmospheric CO2 from Ginkgo stomatal index last revised in 2009.

Economic burden of varicella in children 1-12 years of age in Argentina, 2009-2014.

PubMed

Giglio, Norberto; Monsanto, Homero; Rampakakis, Emmanouil; Yang, H Keri; Kuter, Barbara J; Wolfson, Lara J

2018-04-01

In Argentina, varicella vaccination was included in the national schedule for mandatory immunizations in 2015. The vaccine has been shown to substantially reduce the morbidity and mortality associated with the virus. The purpose of this study was to evaluate the clinical and economic burden associated with varicella in Argentina prior to vaccine introduction. This was a multi-center, retrospective chart review study among patients aged 1-12 years with a primary varicella diagnosis in 2009-2014 in Argentina. Healthcare resource utilization (HCRU) associated with varicella and its complications, unit costs, and work loss were used to estimate direct and indirect costs. All costs are presented in 2015 United States dollars (USD). One hundred and fifty children with varicella were included (75 outpatients, 75 inpatients), with a mean age of 3.8 (SD = 2.4) and 2.9 (SD = 2.2) years, respectively. One or more complications were experienced by 28.0% of outpatients and 98.7% of inpatients, the most common being skin and soft tissue infections, pneumonia, sepsis, cerebellitis, and febrile seizure. HCRU estimates included use of over-the-counter (OTC) medications (58.7% outpatients, 94.7% inpatients), prescription medications (26.7% outpatients, 77.3% inpatients), tests/procedures (13.3% outpatients, 70.7% inpatients), and consultation with allied health professionals (1.3% outpatients, 32.0% inpatients). The average duration of hospital stay was 4.9 (95% CI = 4.2-5.7) days, and the average duration of ICU stay was 4.8 (95% CI = 1.6-14.1) days. The total combined direct and indirect cost per varicella case was 2947.7 USD (inpatients) and 322.7 USD (outpatients). The overall annual cost of varicella in Argentina for children aged ≤14 years in 2015 was estimated at 40,054,378.0 USD. The clinical burden of varicella in Argentina was associated with utilization of significant amounts of healthcare resources, resulting in substantial economic costs. These costs should be reduced with the recent implementation of routine vaccination of children.

Reconstruction of Pleistocene Paleo-Hydrology and Climate Variations in Western Asia as Recorded in Speleothems from West-Central Iran

NASA Astrophysics Data System (ADS)

Mehterian, S.; Pourmand, A.; Sharifi, A.; Lahijani, H. A. K.; Naderi, M.; Swart, P. K.

2014-12-01

Extending from the eastern Mediterranean Sea to the northwest Indian Ocean and modern Iran, West Asia represents one of the most climatically dynamic regions in the northern hemisphere. The regional climate of West Asia is governed by interactions between the mid-latitude Westerlies, the Siberian Anticyclone and the Indian Ocean Summer Monsoon. In recent years, sparse records of Pleistocene climate variability have emerged from cave deposits (speleothems) in East Asia, the Arabian Peninsula and eastern Mediterranean. However, there remains a large gap in our understanding of abrupt and long-term climate variability in this region. We present for the first time δ18O data from speleothem and water samples that were collected from two cave systems in west-central Iran at similar latitudes, 60km apart: Qaleh Kord Cave (QKC, 35°47'50"N, 48°51'25"E) and Kataleh Khor Cave (KKC, 35°50'09"N, 48°09'41"E). U-Th geochronometry in two stalagmites from QKC yielded ages that range from 73,000 to 118,000 years B.P. Likewise, two stalagmites dated from KKC yielded ages 214,000-260,000 years B.P. and 300,000-500,000 years B.P. The analysis of additional speleothems from these caves should help to establish a continuous half million year multi-proxy record of δ18O variations, trace metal composition (Mg/Ca, Sr/Ca), and radiogenic Sr isotopes in these cave systems. High-resolution δ18O analyses of QKC stalagmites show patterns of variation that can be attributed to Marine Isotope Stage (MIS) 5a and 5b. Since both these caves sit at relatively high elevations (QKC: 2,160 masl, KKC: 1,695 masl) far from major seas (1,100km from Mediterranean Sea, 1,500km from North Indian Ocean), this record potentially reflects the synoptic interactions between the Westerlies and the Siberian Anticyclone during this time interval, as opposed to direct variations caused by sea level fluctuations. Measurements of drip water composition and modern environmental parameters (temperature, relative humidity and pCO2) inside the caves paired with δ18O analyses of fluid inclusions in the stalagmites will place additional constraints on multi-proxy reconstruction of paleo-records from these cave systems.

Gradient-based model calibration with proxy-model assistance

NASA Astrophysics Data System (ADS)

Burrows, Wesley; Doherty, John

2016-02-01

Use of a proxy model in gradient-based calibration and uncertainty analysis of a complex groundwater model with large run times and problematic numerical behaviour is described. The methodology is general, and can be used with models of all types. The proxy model is based on a series of analytical functions that link all model outputs used in the calibration process to all parameters requiring estimation. In enforcing history-matching constraints during the calibration and post-calibration uncertainty analysis processes, the proxy model is run for the purposes of populating the Jacobian matrix, while the original model is run when testing parameter upgrades; the latter process is readily parallelized. Use of a proxy model in this fashion dramatically reduces the computational burden of complex model calibration and uncertainty analysis. At the same time, the effect of model numerical misbehaviour on calculation of local gradients is mitigated, this allowing access to the benefits of gradient-based analysis where lack of integrity in finite-difference derivatives calculation would otherwise have impeded such access. Construction of a proxy model, and its subsequent use in calibration of a complex model, and in analysing the uncertainties of predictions made by that model, is implemented in the PEST suite.

Prevalence and determinants of misreporting among European children in proxy-reported 24 h dietary recalls.

PubMed

Börnhorst, C; Huybrechts, I; Ahrens, W; Eiben, G; Michels, N; Pala, V; Molnár, D; Russo, P; Barba, G; Bel-Serrat, S; Moreno, L A; Papoutsou, S; Veidebaum, T; Loit, H-M; Lissner, L; Pigeot, I

2013-04-14

Dietary assessment is strongly affected by misreporting (both under- and over-reporting), which results in measurement error. Knowledge about misreporting is essential to correctly interpret potentially biased associations between diet and health outcomes. In young children, dietary data mainly rely on proxy respondents but little is known about determinants of misreporting here. The present analysis was conducted within the framework of the multi-centre IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) study and is based on 6101 children aged 2-9 years with 24 h dietary recall (24-HDR) and complete covariate information. Adapted Goldberg cut-offs were applied to classify the 24-HDR as 'over-report', 'plausible report' or 'under-report'. Backward elimination in the course of multi-level logistic regression analyses was conducted to identify factors significantly related to under- and over-reporting. Next to characteristics of the children and parents, social factors and parental concerns/perceptions concerning their child's weight status were considered. Further selective misreporting was addressed, investigating food group intakes commonly perceived as more or less socially desirable. Proportions of under-, plausible and over-reports were 8.0, 88.6 and 3.4 %, respectively. The risk of under-reporting increased with age (OR 1.19, 95 % CI 1.05, 1.83), BMI z-score of the child (OR 1.23, 95 % CI 1.10, 1.37) and household size (OR 1.12, 95 % CI 1.01, 1.25), and was higher in low/medium income groups (OR 1.45, 95 % CI 1.13, 1.86). Over-reporting was negatively associated with BMI z-scores of the child (OR 0.78, 95 % CI 0.69, 0.88) and higher in girls (OR 1.70, 95 % CI 1.27, 2.28). Further social desirability and parental concerns/perceptions seemed to influence the reporting behaviour. Future studies should involve these determinants of misreporting when investigating diet-disease relationships in children to correct for the differential reporting bias.

Intraseasonal variability in subtropical South America as depicted by precipitation data

NASA Astrophysics Data System (ADS)

González, P. L. M.; Vera, C. S.; Liebmann, B.; Kiladis, G.

2008-06-01

Daily precipitation data from three stations in subtropical Argentina are used to describe intraseasonal variability (20 90 days) during the austral summer. This variability is compared locally and regionally with that present in outgoing longwave radiation (OLR) data, in order to evaluate the performance of this variable as a proxy for convection in the region. The influence of the intraseasonal activity of the South American Seesaw (SASS) leading convection pattern on precipitation is also explored. Results show that intraseasonal variability explains a significant portion of summer precipitation variance, with a clear maximum in the vicinity of the SASS subtropical center. Correlation analysis reveals that OLR can explain only a small portion of daily precipitation variability, implying that it does not constitute a proper proxy for precipitation on daily timescales. On intraseasonal timescales, though, OLR is able to reproduce the main features of precipitation variability. The dynamical conditions that promote the development of intraseasonal variability in the region are further analyzed for selected summers. Seasons associated with a strong intraseasonal signal in precipitation variability show distinctive wet/dry intraseasonal periods in daily raw data, and are associated with a well defined SASS-like spatial pattern of convection. During these summers, strong large-scale forcing (such as warm El Niño/Southern Oscillation (ENSO) events and/or tropical intraseasonal convective activity), and Rossby-wave-like circulation anomalies extending across the Pacific Ocean, are also observed.

Centennial-scale links between Atlantic Ocean dynamics and hydroclimate over the last 4400 years: Insights from the northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Thirumalai, K.; Quinn, T. M.; Okumura, Y.; Richey, J. N.; Partin, J. W.; Poore, R. Z.

2015-12-01

Surface circulation in the Atlantic Ocean is an important mediator of global climate and yet its variability is poorly constrained on centennial timescales. Changes in the Atlantic meridional overturning circulation (AMOC) have been implicated in late Holocene climate variability in the Western Hemisphere, although the relationship between AMOC variability and hydroclimate is uncertain due to the lack of sufficiently highly resolved proxy records. Here we present a replicated reconstruction of sea-surface temperature (SST) and salinity (SSS) from the Garrison Basin in the northern Gulf of Mexico (NGOM) spanning the last 4,400 years to better constrain past sea-surface conditions. We generated time series of paired Mg/Ca (SST proxy) and δ18O (SST and SSS proxy) variations in planktic foraminifer Globigerinoides ruber (white variety) from three multi-cores collected in 2010. Using a Monte Carlo-based technique we produce a stacked record from the three multi-cores and constrain analytical, calibration, chronological, and sampling uncertainties. We apply this technique to existing paired Mg/Ca- δ18O studies in the Gulf of Mexico and Atlantic Ocean to facilitate comparison between time-uncertain proxy reconstructions. The Garrison Basin stack exhibits large centennial-scale variability (σSST~0.6°C; δ18Osw~0.17‰) and indicates a substantially cool (0.9±0.5°C) and fresh (0.26±0.1‰) Little Ice Age (LIA; 1450-1850 A.D.), corroborating extant records from the Gulf of Mexico. Focusing on the last millennium, we analyze a suite of oceanic and terrestrial proxy records to demonstrate a centennial-scale link between salt advection in the Atlantic Ocean, a diagnostic parameter of ocean circulation, and hydroclimate in the adjacent continents. The ensuing multiproxy relationships seem to be consistent with spatial field correlations of limited salinity and rainfall instrumental/reanalysis data, which suggest that NGOM salinity varies with large-scale Atlantic Ocean circulation and continental precipitation. Our results imply significant centennial-scale variability over the late Holocene and are consistent with limited observational analysis indicating a slowdown of AMOC during the LIA.

Mid- to Late Holocene climate development in Central Asia as revealed from multi-proxy analyses of sediments from Lake Son Kol (Kyrgyzstan)

NASA Astrophysics Data System (ADS)

Lauterbach, Stefan; Dulski, Peter; Gleixner, Gerd; Hettler-Riedel, Sabine; Mingram, Jens; Plessen, Birgit; Prasad, Sushma; Schwalb, Antje; Schwarz, Anja; Stebich, Martina; Witt, Roman

2013-04-01

A mid-Holocene shift from predominantly wet to significantly drier climate conditions, attributed to the weakening of the Asian summer monsoon (ASM), is documented in numerous palaeoclimate records from the monsoon-influenced parts of Asia, e.g. the Tibetan Plateau and north- and southeastern China. In contrast, Holocene climate development in the arid regions of mid-latitude Central Asia, located north and northwest of the Tibetan Plateau, is less well-constrained but supposed to have been influenced by a complex interaction between the mid-latitude Westerlies and the ASM. Hence, well-dated and highly resolved palaeoclimate records from Central Asia might provide important information about spatio-temporal changes in the regional interplay between Westerlies and ASM and thus aid the understanding of global climate teleconnections. As a part of the project CADY (Central Asian Climate Dynamics), aiming at reconstructing past climatic and hydrological variability in Central Asia, several sediment cores were recovered from alpine Lake Son Kol (41° 48'N, 75° 12'E, 3016 m a. s. l.) in the Central Tian Shan of Kyrgyzstan. A radiocarbon-dated sediment sequence of 154.5 cm length, covering approximately the last 6000 years, was investigated by using a multi-proxy approach, including sedimentological, (bio)geochemical, isotopic and micropalaeontological analyses. Preliminary proxy data indicate hydrologically variable but predominantly wet conditions until ca. 5100 cal. a BP, characterized by the deposition of finely laminated organic-carbonatic sediments. In contrast to monsoonal Asia, where a distinct trend towards drier conditions is observed since the mid-Holocene, the hydrologically variable interval at Lake Son Kol was apparently followed by an only short-term dry episode between ca. 5100 and 4200 cal. a BP. This is characterized by a higher δD of the C29 n-alkanes, probably reflecting increased evapotranspiration. Also pollen, diatom and ostracod data point towards drier climate conditions. Higher δ15N values during this period may also reflect increased evaporation but could also be related to dust input of NOx, being in agreement with high amounts of fine-grained minerogenic material. Further periods of higher δ15N values and contents of fine-grained minerogenic material occurred at 3600-3000 and 2000-1600 cal. a BP. However, as biogeochemical data indicate no further distinct dry episodes since about 4200 cal. a BP, these intervals most probably reflect increased dust deposition. Finally, a trend towards wetter climate conditions can be observed during the last ca. 1500 years, reflected by high ostracod and diatom diversity and (bio)geochemical data. The absence of a pronounced drying trend since the mid-Holocene, as observed in monsoonal Asia, is largely consistent with results from other regional palaeoclimate records and might reflect the predominant influence of the strengthening mid-latitude Westerlies on regional climate since this time.

Coupling δ18O values of rodent tooth and mollusc shell carbonates: a new approach to reconstructing Pleistocene palaeotemperatures?

NASA Astrophysics Data System (ADS)

Peneycad, Elizabeth; Candy, Ian; Schreve, Danielle

2017-04-01

The ratio of stable oxygen isotopes in fossil rodent teeth (δ18Ort) can potentially provide valuable quantitative information about terrestrial palaeoclimate conditions. Grimes et al. (2004) suggested that δ18Ort could be usefully combined with the δ18O values of coeval biominerals, e.g. mollusc shells (δ18Oms), to estimate past summer temperatures during the Quaternary period. Nevertheless, until now, the application of this approach to Quaternary palaeoclimate reconstruction has remained unexplored. In addition, the success of this approach is dependent upon the establishment of a statistically robust relationship between δ18Ort and the δ18O of meteoric water (δ18Omw) in the modern environment. However, such a relationship is yet to be quantified in relation to rodent tooth carbonate. Here, we present the preliminary results of 2 studies investigating the validity of δ18Ort as a climate proxy. Firstly, isotope analyses were undertaken on modern vole (Microtus agrestis) teeth from 3 locations across the UK. The results of these analyses reveal a significant linear correlation between the mean δ18Ort and the mean δ18Omw. These findings therefore demonstrate that a quantifiable relationship exists between δ18Ort and δ18Omw, highlighting the potential of δ18Ort as an accurate recorder of local climatic conditions. This modern relationship was subsequently applied to the reconstruction of past δ18Omw values for two Pleistocene interglacial sites in the UK. The δ18Omw values were calculated using δ18Ort, and then combined with δ18Oms values derived from coeval fossil gastropod assemblages in order to estimate mean summer palaeotemperatures. The results of these calculations are in close agreement with multi-proxy temperature reconstructions derived from the same deposits. This suggests that coupling the δ18O values of rodent tooth and mollusc shell carbonates offers great potential as an approach to quantifying summer palaeotemperatures in Europe, particularly for carbonate-rich sites at which alternative temperature proxies may be unavailable. References: Grimes, S.T., Mattey, D.P., Collinson, M.E. & Hooker, J.J. (2004) Using mammal tooth phosphate with freshwater carbonate and phosphate palaeoproxies to obtain mean paleotemperatures. Quaternary Science Reviews, 23, pp.967-976.

Assessment of the role of small mammals in the transmission cycle of tegumentary leishmaniasis and first report of natural infection with Leishmania braziliensis in two sigmodontines in northeastern Argentina.

PubMed

Fernández, María S; Fraschina, Jimena; Acardi, Soraya; Liotta, Domingo J; Lestani, Eduardo; Giuliani, Magalí; Busch, María; Salomón, O Daniel

2018-02-01

To contribute to the knowledge of the role of small mammals in the transmission cycle of tegumentary leishmaniasis caused by Leishmania braziliensis, we studied the small mammal community and its temporal and spatial association with phlebotominae, as well as small mammal infection by Leishmania spp. by PCR-RFLP analyses in an endemic area of northeastern Argentina. Ten small mammal samplings were conducted (2007-2009, 7506 Sherman trap nights and 422 cage trap nights). In two of these samplings, 16 capture stations each one consisting of a CDC light trap to capture phlebotominae, two to four Sherman traps and two cage traps were placed. We found co-occurrence of phlebotominae and small mammal captures in four stations, which were all the stations with small mammal captures and yielded 97% (2295 specimens, including 21 gravid females) of the total phlebotominae captures, suggesting that small mammals may provide a potential source of blood for phlebotominae females. One Didelphis albiventris and two Rattus rattus were associated with high captures of Nyssomyia whitmani, vector of L. braziliensis in the study area. The PCR-RFLP analyses confirm the presence of L. braziliensis in two sigmodontine small mammals (Akodon sp. and Euryoryzomys russatus) for the first time in Argentina, to our knowledge.

Dietary patterns, overweight and obesity from 1961 to 2011 in the socioeconomic and political context of Argentina.

PubMed

Silberman, Martín; Moreno-Altamirano, Laura; Hernández-Montoya, Dewi; Capraro, Santiago; García-García, Juan José; Soto-Estrada, Guadalupe

2017-02-01

To analyse the changes in eating patterns in Argentina from 1961 to 2011, and to assess changes in overweight and obesity in their socioeconomic and political context, we performed a hierarchical cluster analysis. We used the information from Food Balance Sheets of the United Nations Food and Agriculture Organisation to identify dietary patterns of apparent consumption. Years were grouped into five patterns. The food group with the highest apparent consumption was cereals (30% of total kcal/person/day) although this decreased slightly. Meats were second and their contribution decreased by 12%. The following foods contribution increased during the period: Sugar and milk by 2% and vegetable oils by 6%. The changes observed in the number of kcal/person/day were in line with changes in real wage, and coincided with economic and political crises that Argentina experienced during that period. Changes in eating patterns allow us to interpret that they relate to the increase in overweight and obesity.

Early meteorological records from Latin-America and the Caribbean during the 18th and 19th centuries

NASA Astrophysics Data System (ADS)

Domínguez-Castro, Fernando; Vaquero, José Manuel; Gallego, María Cruz; Farrona, Ana María Marín; Antuña-Marrero, Juan Carlos; Cevallos, Erika Elizabeth; Herrera, Ricardo García; de La Guía, Cristina; Mejía, Raúl David; Naranjo, José Manuel; Del Rosario Prieto, María; Ramos Guadalupe, Luis Enrique; Seiner, Lizardo; Trigo, Ricardo Machado; Villacís, Marcos

2017-11-01

This paper provides early instrumental data recovered for 20 countries of Latin-America and the Caribbean (Argentina, Bahamas, Belize, Brazil, British Guiana, Chile, Colombia, Costa Rica, Cuba, Ecuador, France (Martinique and Guadalupe), Guatemala, Jamaica, Mexico, Nicaragua, Panama, Peru, Puerto Rico, El Salvador and Suriname) during the 18th and 19th centuries. The main meteorological variables retrieved were air temperature, atmospheric pressure, and precipitation, but other variables, such as humidity, wind direction, and state of the sky were retrieved when possible. In total, more than 300,000 early instrumental data were rescued (96% with daily resolution). Especial effort was made to document all the available metadata in order to allow further post-processing. The compilation is far from being exhaustive, but the dataset will contribute to a better understanding of climate variability in the region, and to enlarging the period of overlap between instrumental data and natural/documentary proxies.

Early meteorological records from Latin-America and the Caribbean during the 18th and 19th centuries.

PubMed

Domínguez-Castro, Fernando; Vaquero, José Manuel; Gallego, María Cruz; Farrona, Ana María Marín; Antuña-Marrero, Juan Carlos; Cevallos, Erika Elizabeth; Herrera, Ricardo García; de la Guía, Cristina; Mejía, Raúl David; Naranjo, José Manuel; Del Rosario Prieto, María; Ramos Guadalupe, Luis Enrique; Seiner, Lizardo; Trigo, Ricardo Machado; Villacís, Marcos

2017-11-14

This paper provides early instrumental data recovered for 20 countries of Latin-America and the Caribbean (Argentina, Bahamas, Belize, Brazil, British Guiana, Chile, Colombia, Costa Rica, Cuba, Ecuador, France (Martinique and Guadalupe), Guatemala, Jamaica, Mexico, Nicaragua, Panama, Peru, Puerto Rico, El Salvador and Suriname) during the 18th and 19th centuries. The main meteorological variables retrieved were air temperature, atmospheric pressure, and precipitation, but other variables, such as humidity, wind direction, and state of the sky were retrieved when possible. In total, more than 300,000 early instrumental data were rescued (96% with daily resolution). Especial effort was made to document all the available metadata in order to allow further post-processing. The compilation is far from being exhaustive, but the dataset will contribute to a better understanding of climate variability in the region, and to enlarging the period of overlap between instrumental data and natural/documentary proxies.

Cap rock efficiency of geothermal systems in fold-and-thrust belts: Evidence from paleo-thermal and structural analyses in Rosario de La Frontera geothermal area (NW Argentina)

NASA Astrophysics Data System (ADS)

Maffucci, R.; Corrado, S.; Aldega, L.; Bigi, S.; Chiodi, A.; Di Paolo, L.; Giordano, G.; Invernizzi, C.

2016-12-01

Cap rock characterization of geothermal systems is often neglected despite fracturing may reduce its efficiency and favours fluid migration. We investigated the siliciclastic cap rock of Rosario de La Frontera geothermal system (NW Argentina) in order to assess its quality as a function of fracture patterns and related thermal alteration. Paleothermal investigations (XRD on fine-grained fraction of sediments, organic matter optical analysis and fluid inclusions on veins) and 1D thermal modelling allowed us to distinguish the thermal fingerprint associated to sedimentary burial from that related to fluid migration. The geothermal system is hosted in a Neogene N-S anticline dissected by high angle NNW- and ENE-striking faults. Its cap rock can be grouped into two quality categories: rocks acting as good insulators, deformed by NNW-SSE and E-W shear fractures, NNE-SSW gypsum- and N-S-striking calcite-filled veins that developed during the initial stage of anticline growth. Maximum paleo-temperatures (< 60 °C) were experienced during deposition to folding phases. rocks acting as bad insulators, deformed by NNW-SSE fault planes and NNW- and WNW-striking sets of fractures associated to late transpressive kinematics. Maximum paleo-temperatures higher than about 115 °C are linked to fluid migration from the reservoir to surface (with a reservoir top at maximum depths of 2.5 km) along fault damage zones. This multi-method approach turned out to be particularly useful to trace the main pathways of hot fluids and can be applied in blind geothermal systems where either subsurface data are scarce or surface thermal anomalies are lacking.

Cenozoic foreland basin evolution during Andean shortening in the Malargüe region of western Argentina (35°S)

NASA Astrophysics Data System (ADS)

Ramirez, S. G.; Horton, B. K.; Fuentes, F.

2015-12-01

Cenozoic clastic deposits in western Argentina provide key opportunities to evaluate the timing and duration of Andean deformation and uplift. We studied the Malargüe segment of the Andean foreland basin at 35°S to better understand latest Cretaceous to Pliocene deformation and eastward propagation of Andean retroarc shortening. Our multi-technique approach included logging of a well-exposed ~1500m Paleocene-Miocene stratigraphic succession, paleocurrent measurements, conglomerate clast counts, and detrital zircon U-Pb geochronological analyses of basin fill exposed in the Sosneado region along the Rio Atuel. The Pircala and Coihueco Formations define the lowermost ~180 m of the section and are represented by fine to medium sandstones, siltstones, claystones and marls interpreted as distal fluvial floodplain and localized lacustrine deposits. Pircala paleocurrents show a major reversal from west- to east-directed flow. These finer deposits of the lower succession are separated from the overlying coarser-grained ~800 m thick Agua de la Piedra Formation by a conspicuous unconformity that spans up to roughly 20 Myr. The Agua de la Piedra Formation is composed of upward-coarsening amalgamated beds of massive medium to coarse sandstones and lenticular conglomerates interpreted as a prograding proximal fluvial to alluvial fan system. Conglomerate clast counts show initial dominance by Mesozoic detritus from the pre-Andean Neuquen basin system, with a progressive upsection increase in Cenozoic volcanic detritus from the Andean magmatic arc. Collectively, the paleocurrents, clast compositions, sedimentary facies associations, and emerging U-Pb results suggest a long-term shift, commencing in the Paleocene, from eastern cratonic sources to magmatic-arc and thrust-belt sources during a systematic eastward propagation of deformation, with a pronounced phase of Miocene magmatism and shortening that incorporated the proximal foreland basin into the advancing thrust belt.

On the space monitoring of the Sassi and Murgia Park (Matera UNESCO site) using LANDSAT time series

NASA Astrophysics Data System (ADS)

Lanorte, Antonio; Nole, Gabriele; Manzi, Teresa; Lasaponara, Rosa

2015-04-01

This paper is focused on the preliminary results obtained in the framework of the Great relevance project " Smart management of cultural heritage sites in Italy and Argentina: Earth Observation and pilot projects funded by the Ministero degli Affari Esteri e della Cooperazione Internazionale --MAE, 17/04/2014, Prot. nr. 0090692, 2014-2016. A temporal series (1999-2011) of the LANDSAT TM data was used to carried out investigation in the Murgia Park enclosed in the Matera UNESCO site . The PCA was adopted to enhance regions of localized change in multi-temporal data sets (Lasaponara 2006). Both naturally vegetated areas (forest, shrub-land, herbaceous cover) and agricultural lands have been investigated in order to extract the most prominent natural and/or man induced alterations affecting soil and vegetation cover. Results from PCA were compared with independent data sets and field survey to evaluate the reliability of the obtained maps of the ongoing land degradation phenomenon. Such analyses can provide valuable information for an operational monitoring of the status of vegetation which is an indicator of the degree of stress namely any disturbance that adversely influences plants in response to natural hazards and/or anthropogenic activities. Our findings suggest that the Landsat TM time series can provide valuable information for environmental management policies involving biodiversity preservation and rational exploitation of natural and agricultural resources. Acknowledgement This research was performed within the framework of the Great relevance project " Smart management of cultural heritage sites in Italy and Argentina: Earth Observation and pilot projects funded by the Ministero degli Affari Esteri e della Cooperazione Internazionale --MAE, 17/04/2014, Prot. nr. 0090692, 2014-2016

Serotype diversity of Streptococcus mutans and caries activity in children in Argentina.

PubMed

Carletto-Körber, F P; González-Ittig, R E; Jimenez, M G; Cornejo, L S

2015-09-01

The purpose of this study was to analyse the serotype distribution of S. mutans and their association with caries activity in school children from Córdoba, Argentina. Clinical examination was performed in 133 children. The dmft+DMFT and Significant Caries (SiC) indices were calculated to identify individuals with high caries activity. After DNA extractions of S. mutans strains, serotypes were determined by PCR amplifications. The median caries activity of each serotype group was compared using a non-parametric Kruskall-Wallis test. We obtained S. mutans strains from stimulated saliva of 94 children. The mean dmft+DMFT was 4.14 and the mean SiC index was 8.65. Serotype c was the most frequent (53.2%), followed by e (31.9%), f (8.5%) and k (6.4%). The comparison between the SiC and Non-Sic groups showed significant differences in the frequency of serotypes c and k. The median caries activity was non-significant in the different serotypes. The difference between the serotype frequencies detected in Argentina compared to those of other countries could be related with contrasting dietary habits. The results obtained in the present study would increase the knowledge about the epidemiology of dental caries in children from Argentina.

Advective transport in heterogeneous aquifers: Are proxy models predictive?

NASA Astrophysics Data System (ADS)

Fiori, A.; Zarlenga, A.; Gotovac, H.; Jankovic, I.; Volpi, E.; Cvetkovic, V.; Dagan, G.

2015-12-01

We examine the prediction capability of two approximate models (Multi-Rate Mass Transfer (MRMT) and Continuous Time Random Walk (CTRW)) of non-Fickian transport, by comparison with accurate 2-D and 3-D numerical simulations. Both nonlocal in time approaches circumvent the need to solve the flow and transport equations by using proxy models to advection, providing the breakthrough curves (BTC) at control planes at any x, depending on a vector of five unknown parameters. Although underlain by different mechanisms, the two models have an identical structure in the Laplace Transform domain and have the Markovian property of independent transitions. We show that also the numerical BTCs enjoy the Markovian property. Following the procedure recommended in the literature, along a practitioner perspective, we first calibrate the parameters values by a best fit with the numerical BTC at a control plane at x1, close to the injection plane, and subsequently use it for prediction at further control planes for a few values of σY2≤8. Due to a similar structure and Markovian property, the two methods perform equally well in matching the numerical BTC. The identified parameters are generally not unique, making their identification somewhat arbitrary. The inverse Gaussian model and the recently developed Multi-Indicator Model (MIM), which does not require any fitting as it relates the BTC to the permeability structure, are also discussed. The application of the proxy models for prediction requires carrying out transport field tests of large plumes for a long duration.

Phytogeographic patterns and cryptic diversity in an aposematic toad from NW Argentina.

PubMed

Clemente-Carvalho, Rute B; Vaira, Marcos; King, Laura E; Koscinski, Daria; Bonansea, Maria I; Lougheed, Stephen C

2017-11-01

The Yungas Redbelly Toad, Melanophryniscus rubriventris, is patchily distributed in Argentina, confined to the upland portion (1000-2000m above sea level) of the montane forests of northern and central regions of Salta, and in central-eastern and south-eastern Jujuy. This species is known for its striking aposematic color variation across its geographic distribution, and was once treated as a complex of three subspecies based on distinctive color patterns. Here we assess the geographical genetic variation within M. rubriventris and quantify divergence in color and pattern among individuals sampled from Northwestern Argentina. We compare multi-gene phylogeography of M. rubriventris to patterns of dorsal and ventral coloration to test whether evolutionary affinities predict variation in warning color. Our results reveal two well-supported species lineages: one confined to the extreme northern portion of our sampling area, and the other extending over most of the Argentine portion of the species' range, within which there are two populations. However, these well-supported evolutionary relationships do not mirror the marked variation in warning coloration. This discordance between DNA genealogy and warning color variation may reflect selection brought about by differences in local predation pressures, potentially coupled with effects of sexual selection and thermoregulation. Copyright © 2017 Elsevier Inc. All rights reserved.

Evolution of the Climate Continuum from the Mid-Miocene Climatic Optimum to the Present

NASA Astrophysics Data System (ADS)

Aswasereelert, W.; Meyers, S. R.; Hinnov, L. A.; Kelly, D.

2011-12-01

The recognition of orbital rhythms in paleoclimate data has led to a rich understanding of climate evolution during the Neogene and Quaternary. In contrast, changes in stochastic variability associated with the transition from unipolar to bipolar glaciation have received less attention, although the stochastic component likely preserves key insights about climate. In this study, we seek to evaluate the dominance and character of stochastic climate energy since the Middle Miocene Climatic Optimum (~17 Ma). These analyses extend a previous study that suggested diagnostic stochastic responses associated with Northern Hemisphere ice sheet development during the Plio-Pleistocene (Meyers and Hinnov, 2010). A critical and challenging step necessary to conduct the work is the conversion of depth data to time data. We investigate climate proxy datasets using multiple time scale hypotheses, including depth-derived time scales, sedimentologic/geochemical "tuning", minimal orbital tuning, and comprehensive orbital tuning. To extract the stochastic component of climate, and also explore potential relationships between the orbital parameters and paleoclimate response, a number of approaches rooted in Thomson's (1982) multi-taper spectral method (MTM) are applied. Importantly, the MTM technique is capable of separating the spectral "continuum" - a measure of stochastic variability - from the deterministic periodic orbital signals (spectral "lines") preserved in proxy data. Time series analysis of the proxy records using different chronologic approaches allows us to evaluate the sensitivity of our conclusion about stochastic and deterministic orbital processes during the Middle Miocene to present. Moreover, comparison of individual records permits examination of the spatial dependence of the identified climate responses. Meyers, S.R., and Hinnov, L.A. (2010), Northern Hemisphere glaciation and the evolution of Plio-Pleistocene climate noise: Paleoceanography, 25, PA3207, doi:10.1029/2009PA001834. Thomson, D.J. (1982), Spectrum estimation and harmonic analysis: IEEE Proceedings, v. 70, p. 1055-1096.

Droughts in the East Asian summer monsoon margin during the last 6 kyrs: Link to the North Atlantic cooling events

NASA Astrophysics Data System (ADS)

Fan, Jiawei; Xiao, Jule; Wen, Ruilin; Zhang, Shengrui; Wang, Xu; Cui, Linlin; Li, He; Xue, Dingshuai; Yamagata, Hideki

2016-11-01

Teleconnections to the high latitudes, forcing by the tropical oceans and solar variability have all been suggested as dominant factors in the sub-millennial global climate changes, yet there is little consensus as to the relative importance of these factors for the East Asian summer monsoon (EASM) variability. This study presents the results of high-resolution analyses of Ca and Mg concentrations, Mg/Ca ratio, δ18O and δ13C values of endogenic calcites from a sediment core from Dali Lake in the EASM margin, in order to investigate the sub-millennial EASM variability and its possible driving forces during the last 6 kyrs. Increases in these chemical proxy data were interpreted as drought events in the region due to the intensive evaporation losses overwhelming the water input to the lake. The chemical proxy data in this study combined with multi-proxy indicators including grain size component and total organic carbon concentrations from the same sediment core imply that declines in the EASM intensity may have played a dominant role in triggering the drought events during the last 6 kyrs. The results indicate that the EASM intensity significantly declined at the intervals of 5.8-4.75, 3.2-2.8, 1.65-1.15 and 0.65-0.2 kyrs BP. Large declines in the EASM intensity during the last 6 kyrs correspond in time to occurrences of ice-rafted debris in the North Atlantic, indicating that millennial-to-centennial scale changes in the EASM intensity were mainly controlled by climatic processes occurring in the northern high latitudes. These data imply that persistent global warming may be favorable for the strengthening of the EASM circulation and for the transportation of more rainfall to the semi-arid regions of northern China on sub-millennial scales.

Solar EUV irradiance for space weather applications

NASA Astrophysics Data System (ADS)

Viereck, R. A.

2015-12-01

Solar EUV irradiance is an important driver of space weather models. Large changes in EUV and x-ray irradiances create large variability in the ionosphere and thermosphere. Proxies such as the F10.7 cm radio flux, have provided reasonable estimates of the EUV flux but as the space weather models become more accurate and the demands of the customers become more stringent, proxies are no longer adequate. Furthermore, proxies are often provided only on a daily basis and shorter time scales are becoming important. Also, there is a growing need for multi-day forecasts of solar EUV irradiance to drive space weather forecast models. In this presentation we will describe the needs and requirements for solar EUV irradiance information from the space weather modeler's perspective. We will then translate these requirements into solar observational requirements such as spectral resolution and irradiance accuracy. We will also describe the activities at NOAA to provide long-term solar EUV irradiance observations and derived products that are needed for real-time space weather modeling.

Roman and early-medieval routes in north-western Europe: modelling national and international frequent-travel zones in the Netherlands using a multi-proxy approach.

NASA Astrophysics Data System (ADS)

van Lanen, Rowin J.; Jansma, Esther

2016-04-01

The end of the Roman period in many parts of north-western Europe coincided with severe population decline and collapsing trade routes. To what extent the long-distance transport routes changed from Roman to early-medieval periods and what their exact nature was, is generally unknown. Only few historical sources are available for this period, and archaeological records complex. Traditionally, research on the long-distance exchange of goods therefore generally has focussed on the spatial analyses of archaeologically recognizable goods (e.g. jewellery, religious artefacts). Although these endeavours greatly increase our understanding of long-distance trade networks, they probably in itself do not represent the full spectrum of common exchange networks and transport routes. By using a dendroarchaeological approach we were able to analyse long-distance transport routes of imported timber in the Roman and early-medieval Netherlands. By combining the provenance of exogenous timbers with data on modelled Roman and early-medieval route networks, we were able to reconstruct: (a) Roman and early-medieval trade networks in structural timbers, (b) changing transport routes in structural timbers and (c) model spatially shifting frequent-travel zones in the research area.

Multi-proxy Paleoclimate and CO2 Reconstruction from the Latest Middle Eocene Sedimentary Fill of a Subarctic Kimberlitic Maar Crater

NASA Astrophysics Data System (ADS)

Reyes, A. V.; Wolfe, A. P.; Royer, D. L.; Greenwood, D. R.; Tierney, J. E.; Doria, G.; Gagen, M. H.; Siver, P.; Westgate, J.

2016-12-01

Eocene paleoclimate reconstructions are rarely accompanied by parallel estimates of CO2, complicating assessment of the equilibrium climate responses to CO2. We reconstruct temperature, precipitation, and CO2 from latest middle Eocene ( 38 Myrs ago) peats in subarctic Canada, preserved in sediments that record infilling of a kimberlite pipe maar crater. Mutual climatic range analyses of pollen, together with oxygen isotope analyses of a-cellulose from unpermineralized wood and inferenecs from branched glycerol diakyl glycerol tetraethers (GDGTs), reveal a high-latitude humid-temperate forest ecosystem with mean annual temperatures (MATs) >17 °C warmer than present, mean coldest month temperatures above 0 °C, and mean annual precipitation 4x present. Metasequoia stomatal indices and gas-exchange modeling produce median CO2 concentrations of 634 and 432 ppm, respectively, with a consensus median estimate of 494 ppm. Reconstructed MATs are >6 °C warmer than those produced by Eocene climate models forced at 560 ppm CO2, underscoring the capacity for exceptional polar amplification of warming and hydrological intensification under relatively modest CO2 concentrations, once both fast and slow feedbacks become expressed.

Hydroclimatological data and analyses from a headwaters region of Mongolia as boundary objects in interdisciplinary climate change research

NASA Astrophysics Data System (ADS)

Venable, N. B. H.

2017-09-01

Collaborative work on increasingly complex hydroclimatic investigations often crosses disciplinary boundaries. Elements of scientific inquiry, such as data or the results of analyses can become objectified, or capable of being adopted and/or adapted by users from multiple disciplinary realms. These objects often provide a bridge for collaborative endeavors, or are used as tools by individuals pursuing multi-disciplinary work. Boundary object terminology was first formalized and applied by social scientists. However, few examples of the application of this useful framework are found in the hydrologic literature. The construct is applied here to identify and discuss how common research products and processes are used both internally and externally through providing examples from a project examining the historical and paleo proxy-based hydroclimatology of a headwaters region of Mongolia. The boundary object concept is valuable to consider when conducting and critiquing basic research, collaborating across multiple disciplinary teams as when studying climate change issues, as an individual researcher working in a cross boundary sense using methods from differing disciplines to answer questions, and/or when one group adapts the work of another to their own research problems or interpretive needs, as occurred with selected products of this project.

600 yr High-Resolution Climate Reconstruction of the Atlantic Multidecadal Oscillation deduced from a Puerto Rican Speleothem

NASA Astrophysics Data System (ADS)

Vieten, Rolf; Winter, Amos; Scholz, Denis; Black, David; Spoetl, Christoph; Winterhalder, Sophie; Koltai, Gabriella; Schroeder-Ritzrau, Andrea; Terzer, Stefan; Zanchettin, Davide; Mangini, Augusto

2016-04-01

A multi-proxy speleothem study tracks the regional hydrological variability in Puerto Rico and highlights its close relation to the Atlantic Multidecadal Oscillation (AMO) describing low-frequency sea-surface temperature (SST) variability in the North Atlantic ocean. Our proxy record extends instrumental observations 600 years into the past, and reveals the range of natural hydrologic variability for the region. A detailed interpretation and understanding of the speleothem climate record is achieved by the combination of multi-proxy measurements, thin section petrography, XRD analysis and cave monitoring results. The speleothem was collected in Cueva Larga, a one mile-long cave system that has been monitored since 2012. MC-ICPMS 230Th/U-dating reveals that the speleothem grew constantly over the last 600 years. Trace element ratios (Sr/Ca and Mg/Ca) as well as stable isotope ratios (δ18O and δ13C) elucidate significant changes in atmospheric precipitation at the site. Monthly cave monitoring results demonstrate that the epikarst system responds to multi-annual changes in seepage water recharge. The drip water isotope and trace element composition lack short term or seasonal variability. This hydrological system creates favorable conditions to deduce decadal climate variability from Cueva Larga's climate record. The speleothem time series mimics the most recent AMO reconstruction over the last 200 years (Svendsen et al., 2014) with a time lag of 10-20 years. The lag seems to results from slow atmospheric signal transmission through the epikarst but the effect of dating uncertainties cannot be ruled out. Warm SSTs in the North Atlantic are related to drier conditions in Puerto Rico. During times of decreased rainfall a relative increase in prior calcite precipitation seems to be the main process causing increased Mg/Ca trace element ratios. High trace element ratios correlate to higher δ13C values. The increase in both proxies indicates a shift towards time periods of decreased rainfall. Before 1800 there were two intervals of increased Mg/Ca and δ13C values (dryer conditions) lasting several decades in our speleothem record centered around 1680 CE and 1470 CE. The elevated ratios indicate that drier conditions than present may have occurred in the region during periods of warm Atlantic surface waters.

Self-consistent asset pricing models

NASA Astrophysics Data System (ADS)

Malevergne, Y.; Sornette, D.

2007-08-01

We discuss the foundations of factor or regression models in the light of the self-consistency condition that the market portfolio (and more generally the risk factors) is (are) constituted of the assets whose returns it is (they are) supposed to explain. As already reported in several articles, self-consistency implies correlations between the return disturbances. As a consequence, the alphas and betas of the factor model are unobservable. Self-consistency leads to renormalized betas with zero effective alphas, which are observable with standard OLS regressions. When the conditions derived from internal consistency are not met, the model is necessarily incomplete, which means that some sources of risk cannot be replicated (or hedged) by a portfolio of stocks traded on the market, even for infinite economies. Analytical derivations and numerical simulations show that, for arbitrary choices of the proxy which are different from the true market portfolio, a modified linear regression holds with a non-zero value αi at the origin between an asset i's return and the proxy's return. Self-consistency also introduces “orthogonality” and “normality” conditions linking the betas, alphas (as well as the residuals) and the weights of the proxy portfolio. Two diagnostics based on these orthogonality and normality conditions are implemented on a basket of 323 assets which have been components of the S&P500 in the period from January 1990 to February 2005. These two diagnostics show interesting departures from dynamical self-consistency starting about 2 years before the end of the Internet bubble. Assuming that the CAPM holds with the self-consistency condition, the OLS method automatically obeys the resulting orthogonality and normality conditions and therefore provides a simple way to self-consistently assess the parameters of the model by using proxy portfolios made only of the assets which are used in the CAPM regressions. Finally, the factor decomposition with the self-consistency condition derives a risk-factor decomposition in the multi-factor case which is identical to the principal component analysis (PCA), thus providing a direct link between model-driven and data-driven constructions of risk factors. This correspondence shows that PCA will therefore suffer from the same limitations as the CAPM and its multi-factor generalization, namely lack of out-of-sample explanatory power and predictability. In the multi-period context, the self-consistency conditions force the betas to be time-dependent with specific constraints.

600 yr High-Resolution Climate Reconstruction of the Atlantic Multidecadal Variability deduced from a Puerto Rican Speleothem

NASA Astrophysics Data System (ADS)

Winter, A.; Vieten, R.

2015-12-01

A multi-proxy speleothem study tracks the regional hydrological variability in Puerto Rico and highlights its close relation to the Atlantic Multidecadal Oscillation. Our proxy record extends instrumental observations 600 years into the past, and reveals the range of natural hydrologic variability for the region. A detailed interpretation and understanding of the speleothem climate record is achieved by the combination of multi-proxy measurements, thin section petrography, XRD analysis and cave monitoring results. The speleothem was collected in Cueva Larga, a one mile-long cave system that has been monitored since 2012. MC-ICPMS 230Th/U-dating reveals that the speleothem grew constantly over the last 600 years. Trace element ratios (Sr/Ca and Mg/Ca) as well as stable isotope ratios (δ18O and δ13C) elucidate significant changes in atmospheric precipitation at the site. Monthly cave monitoring results demonstrate that the epikarst system responds to multi-annual changes in seepage water recharge. The drip water isotope and trace element composition lack short term or seasonal variability. This hydrological system creates favorable conditions to deduce decadal climate variability from Cueva Larga's climate record. The speleothem time series mimics the most-recently published AMO reconstruction over the last 200 years with a time lag of 10-20 years. The time lag seems to results from slow atmospheric signal transmission through the epikarst but the effect of dating uncertainties cannot be ruled out. Warm SSTs in the North Atlantic are related to drier conditions in Puerto Rico. During times of decreased rainfall a relative increase in prior calcite precipitation seems to be the main process causing increased Mg/Ca trace element ratios. High trace element ratios correlate to higher δ13C values. The increase in both proxies indicates a shift towards time periods of decreased rainfall. Over the past 600 years there are two intervals of increased Mg/Ca and δ13C values lasting several decades in our speleothem record. They are centered around 1680 CE and 1470 CE. The elevated ratios indicate that drier conditions than present occurred in the region during periods of warm Atlantic surface waters. This may be a precursor of conditions now and to come.

Miguel Sánchez Peña (1925-2009) organizer of the space activities in Argentina

NASA Astrophysics Data System (ADS)

de León, Pablo; Sánchez Peña, Miguel Alejandro

2011-11-01

One of the most important and active pioneers of the space activities in Argentina was Miguel Sánchez Peña, an aeronautical engineer and an officer of the Argentine Air Force. Sánchez Peña was the organizer of Argentina's governmental space program in the 1970s and part of the 80s, and contributed immeasurably to the Nation's sounding rocket program. Born in Mendoza, Argentina in 1925, Sánchez Peña attended the Military Aviation School (Escuela de Aviación Militar) in Córdoba, and later the Air Force Engineering School. Graduated as an engineer in 1959 he was sent to the University of Michigan in the United States to complete his graduate studies earning a Masters of Science degree in Aerospace Engineering. There he had the opportunity to study with several future NASA astronauts such as Theodore Freeman, Edward White and James McDivitt. After his return to Argentina in 1961 he was put in charge of the Space Development Group (Grupo de Desarrollos Espaciales) of the Air Force in Córdoba. While with the Air Force he managed the development of a family of various sounding rockets for high altitude research. Sánchez Peña was also in charge of the first Argentine rockets launched from Antarctica in 1965, as well as the first tests on an Argentine-fabricated rocket (Orión) from Wallops Island in the United States, in 1966. The Orion was the first operational sounding rocket constructed in South America. In the middle of the 1970s Miguel Sánchez Peña was named president of the CNIE (National Space Research Commission). Starting with just a modest one-desk office at the Argentine Air Force headquarters, in only a few years he turned CNIE into a multi-center organization with several hundred employees, three operational launch centers across the country and a family of research rockets open to the international scientific community. He was also actively representing Argentina in many IAF congresses, and was a member of the International Academy of Astronautics. After leaving CNIE he became president of the Asociación Argentina de Ciencias Espaciales (AACE), an IAF Member organization which was the continuation of the space organization created by Teófilo Tabanera in 1951. Miguel Sánchez Peña was, without doubt, the most active president of CNIE and thanks to his vision, hard work and the international trust he created, his efforts made it possible for Argentina to participate in many cooperative space experiments with partners like France, Germany, Perú, the United Kingdom and the United States.

Vegetation, climate and lake changes over the last 7000 years at the boreal treeline in north-central Siberia

NASA Astrophysics Data System (ADS)

Klemm, Juliane; Herzschuh, Ulrike; Pestryakova, Luidmila A.

2016-09-01

Palaeoecological investigations in the larch forest-tundra ecotone in northern Siberia have the potential to reveal Holocene environmental variations, which likely have consequences for global climate change because of the strong high-latitude feedback mechanisms. A sediment core, collected from a small lake (radius ∼100 m), was used to reconstruct the development of the lake and its catchment as well as vegetation and summer temperatures over the last 7100 calibrated years. A multi-proxy approach was taken including pollen and sedimentological analyses. Our data indicate a gradual replacement of open larch forests by tundra with scattered single trees as found today in the vicinity of the lake. An overall trend of cooling summer temperature from a ∼2 °C warmer-than-present mid-Holocene summer temperatures until the establishment of modern conditions around 3000 years ago is reconstructed based on a regional pollen-climate transfer function. The inference of regional vegetation changes was compared to local changes in the lake's catchment. An initial small water depression occurred from 7100 to 6500 cal years BP. Afterwards, a small lake formed and deepened, probably due to thermokarst processes. Although the general trends of local and regional environmental change match, the lake catchment changes show higher variability. Furthermore, changes in the lake catchment slightly precede those in the regional vegetation. Both proxies highlight that marked environmental changes occurred in the Siberian forest-tundra ecotone over the course of the Holocene.

Deglaciation in the High Andes - a Record from Laguna Piuray (Cusco, Peru)

NASA Astrophysics Data System (ADS)

Nederbragt, A.; Thurow, J.; Brumsack, H.; Lowe, J.; Pearce, R.; Ramsey, C.

2007-12-01

The Peruvian Andes lie in a crucial location for paleoclimate investigation. Fluctuating Pacific and Atlantic air masses compete for long-term dominance of the region, with the El-Nino Southern Oscillation (ENSO) system causing further variability. A laminated glacial/interglacial sediment sequence (6m) exposed around the shores of Laguna Piuray, near Cusco, offers not only the potential to reconstruct the climate history of the area but also to test for strength and frequency of the Atlantic monsoonal and Pacific ENSO influence. A suite of continuous cores was collected from deep trenches. The sedimentary record is characterized by postglacial diatom-rich chalk overlying organic-rich clayey chalk. Between these units are 3 distinct organic layers (80% TOC) deposited between 12-14 cal. kyr BP (14C). The base of the record is probably as old as 25kyrs (U/Th). We obtained a multi- proxy record of the section including continuous XRF scanning data of the entire sequence, and stable isotopes, XRF, XRD, TOC, biogenic opal, and carbonate analysis of discrete samples as well as a relative paleotemperature record from analyses of soil biomarkers. All the data profiles we obtained show a pronounced increase in temperature and decrease in precipitation at 13.8kyrs and are in good correlation with published regional Andean records using single proxies. Our results confirm that the Deglaciation Cold Reversal in central South America is not identical to the Younger Dryas event in the Northern Hemisphere.

An empirical analysis of cigarette demand in Argentina

PubMed Central

Martinez, Eugenio; Mejia, Raul; Pérez-Stable, Eliseo J

2014-01-01

Objective To estimate the long-term and short-term effects on cigarette demand in Argentina based on changes in cigarette price and income per person >14 years old. Method Public data from the Ministry of Economics and Production were analysed based on monthly time series data between 1994 and 2010. The econometric analysis used cigarette consumption per person >14 years of age as the dependent variable and the real income per person >14 years old and the real average price of cigarettes as independent variables. Empirical analyses were done to verify the order of integration of the variables, to test for cointegration to capture the long-term effects and to capture the short-term dynamics of the variables. Results The demand for cigarettes in Argentina was affected by changes in real income and the real average price of cigarettes. The long-term income elasticity was equal to 0.43, while the own-price elasticity was equal to −0.31, indicating a 10% increase in the growth of real income led to an increase in cigarette consumption of 4.3% and a 10% increase in the price produced a fall of 3.1% in cigarette consumption. The vector error correction model estimated that the short-term income elasticity was 0.25 and the short-term own-price elasticity of cigarette demand was −0.15. A simulation exercise showed that increasing the price of cigarettes by 110% would maximise revenues and result in a potentially large decrease in total cigarette consumption. Conclusion Econometric analyses of cigarette consumption and their relationship with cigarette price and income can provide valuable information for developing cigarette price policy. PMID:23760657

An empirical analysis of cigarette demand in Argentina.

PubMed

Martinez, Eugenio; Mejia, Raul; Pérez-Stable, Eliseo J

2015-01-01

To estimate the long-term and short-term effects on cigarette demand in Argentina based on changes in cigarette price and income per person >14 years old. Public data from the Ministry of Economics and Production were analysed based on monthly time series data between 1994 and 2010. The econometric analysis used cigarette consumption per person >14 years of age as the dependent variable and the real income per person >14 years old and the real average price of cigarettes as independent variables. Empirical analyses were done to verify the order of integration of the variables, to test for cointegration to capture the long-term effects and to capture the short-term dynamics of the variables. The demand for cigarettes in Argentina was affected by changes in real income and the real average price of cigarettes. The long-term income elasticity was equal to 0.43, while the own-price elasticity was equal to -0.31, indicating a 10% increase in the growth of real income led to an increase in cigarette consumption of 4.3% and a 10% increase in the price produced a fall of 3.1% in cigarette consumption. The vector error correction model estimated that the short-term income elasticity was 0.25 and the short-term own-price elasticity of cigarette demand was -0.15. A simulation exercise showed that increasing the price of cigarettes by 110% would maximise revenues and result in a potentially large decrease in total cigarette consumption. Econometric analyses of cigarette consumption and their relationship with cigarette price and income can provide valuable information for developing cigarette price policy. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Multi-Century Record of Anthropogenic Impacts on an Urbanized Mesotidal Estuary: Salem Sound, MA

EPA Science Inventory

Salem, MA, located north of Boston, has a rich, well-documented history dating back to settlement in 1626 CE, but the associated anthropogenic impacts on Salem Sound are poorly constrained. This project utilized dated sediment cores from the sound to assess the proxy record of an...

Multi-proxy records of Eocene vegetation and climatic dynamics from North America

NASA Astrophysics Data System (ADS)

Sheldon, N. D.; Smith, S. Y.; Stromberg, C. A.; Hyland, E.; Miller, L. A.

2010-12-01

The Eocene is characterized by a “thermal maximum” in the early part, and a shift to “icehouse” conditions by the end of the epoch. Consequently, this is an interesting time to look at vegetation dynamics and understanding plant responses to environmental change, especially as refinement of global climate models is needed if we are to understand future climate change impacts. Paleobotanical evidence, such as phytoliths (plant silica bodies), and paleoenvironmental indicators, such as paleosols, offer an opportunity to study vegetation composition and dynamics in the absence of macrofossils on a variety of spatial and temporal scales. To examine the interaction between paleoclimatic/paleoenvironmental changes and paleovegetation changes, we will compare and contrast two well-dated, high-resolution, multi-proxy records from North America. The margins of the Green River Basin system during the Early Eocene Climatic Optimum (53-50 Ma) are an extremely important location for understanding ecological composition and potential climatic drivers of North American floral diversification, because this area is widely considered the point of origin for many modern grass clades. We examined paleosols preserved in the fluvial, basin-margin Wasatch Formation preserved near South Pass, Wyoming. Field identification of the paleosols indicated a suite that includes Entisols, Inceptisols, and Alfisols. To reconstruct paleovegetation, pedogenic carbonates were analyzed isotopically, and samples were collected and extracted for phytoliths . By combining these paleobotanical proxies with quantitative climatic proxies on whole rock geochemistry, we will present an integrated vegetation-climate history of the EECO at the margins of the Green River Basin. Second, we will present high-resolution record of vegetation patterns based on phytoliths from a section of the Renova Formation, Timberhills region, Montana dated to 39.2 ± 3 Ma. The section is composed of Alfisols, Entisols, Inceptisols, and composite paleosols superimposed onto floodplain sediments. Phytoliths from 27 paleosol horizons were extracted to reconstruct a high-resolution vegetation history. Phytolith morphotypes are predominantly from forest plants, confirming the presence of forests in Montana ~40 Ma. Tropical elements such as palms (Arecaceae) and spiral gingers (Costaceae) are present throughout the section, suggesting this was a paratropical forest. The high-resolution sampling demonstrates that vegetation shifts between three main dominant plant types: woody forest plants, Costaceae, and grasses. The heterogeneity is likely due to succession and vegetation patchiness. High proportions of grasses are correlated with low numbers of aquatic biosilica (diatoms, sponge spicules, chrysophytes) that suggests that these grasses were tolerant of relatively drier conditions, while Costaceae today inhabit forest gaps and margins so represent a specific microhabitat associated with the forest plants. Taken in concert, these two new studies provide examples of high-resolution, multi-proxy records of paleovegetation that can be compared with regional paleoclimatic reconstructions to examine the interplay between climatic and biotic change.

Comparison of clay mineral stratigraphy to other proxy palaeoclimate indicators in the Mesozoic of NW Europe.

PubMed

Ruffell, Alastair; McKinley, Jennifer M; Worden, Richard H

2002-04-15

This paper reviews the opportunities and pitfalls associated with using clay mineralogical analysis in palaeoclimatic reconstructions. Following this, conjunctive methods of improving the reliability of clay mineralogical analysis are reviewed. The Mesozoic succession of NW Europe is employed as a case study. This demonstrates the relationship between clay mineralogy and palaeoclimate. Proxy analyses may be integrated with clay mineralogical analysis to provide an assessment of aridity-humidity contrasts in the hinterland climate. As an example, the abundance of kaolinite through the Mesozoic shows that, while interpretations may be difficult, the Mesozoic climate of NW Europe was subject to great changes in rates of continental precipitation. We may compare sedimentological (facies, mineralogy, geochemistry) indicators of palaeoprecipitation with palaeotemperature estimates. The integration of clay mineralogical analyses with other sedimentological proxy indicators of palaeoclimate allows differentiation of palaeoclimatic effects from those of sea-level and tectonic change. We may also observe how widespread palaeoclimate changes were; whether they were diachronous or synchronous; how climate, sea level and tectonics interact to control sedimentary facies and what palaeoclimate indicators are reliable.

Understanding north-western Mediterranean climate variability: a multi-proxy and multi-sequence approach based on wavelet analysis.

NASA Astrophysics Data System (ADS)

Azuara, Julien; Lebreton, Vincent; Jalali, Bassem; Sicre, Marie-Alexandrine; Sabatier, Pierre; Dezileau, Laurent; Peyron, Odile; Frigola, Jaime; Combourieu-Nebout, Nathalie

2017-04-01

Forcings and physical mechanisms underlying Holocene climate variability still remain poorly understood. Comparison of different paleoclimatic reconstructions using spectral analysis allows to investigate their common periodicities and helps to understand the causes of past climate changes. Wavelet analysis applied on several proxy time series from the Atlantic domain already revealed the first key-issues on the origin of Holocene climate variability. However the differences in duration, resolution and variance between the time-series are important issues for comparing paleoclimatic sequences in the frequency domain. This work compiles 7 paleoclimatic proxy records from 4 time-series from the north-western Mediterranean all ranging from 7000 to 1000 yrs cal BP: -pollen and clay mineral contents from the lagoonal sediment core PB06 recovered in southern France, -Sea Surface Temperatures (SST) derived from alkenones, concentration of terrestrial alkanes and their average chain length (ACL) from core KSGC-31_GolHo-1B recovered in the Gulf of Lion inner-shelf, - δ18O record from speleothems recovered in the Asiul Cave in north-western Spain, -grain size record from the deep basin sediment drift core MD99-2343 north of Minorca island. A comparison of their frequency content is proposed using wavelet analysis and cluster analysis of wavelet power spectra. Common cyclicities are assessed using cross-wavelet analysis. In addition, a new algorithm is used in order to propagate the age model errors within wavelet power spectra. Results are consistents with a non-stationnary Holocene climate variability. The Halstatt cycles (2000-2500 years) depicted in many proxies (ACL, errestrial alkanes and SSTs) demonstrate solar activity influence in the north-western Mediterranean climate. Cluster analysis shows that pollen and ACL proxies, both indicating changes in aridity, are clearly distinct from other proxies and share significant common periodicities around 1000 and 600 years, since the mid-Holocene. The 1000 years period is also evidenced in terrestrial alkanes and Minorca sediment drift grain size, which respectively indicate changes in the Rhône hydrology and changes in the north-western Mediterranean deep water formation. These findings suggests that an original climate driver influences the Gulf of Lion area. Finally, both clay mineral content from PB06, indicative of past storminess and δ18O record from the north western Iberia, related to precipitations, record the well known 1500 years period since the middle Holocene. The presence of this period, widely encountered in the Atlantic, highlights the link between the north-western Mediterranean and the Atlantic climate variability.

A Multi-Proxy Investigation into the Biomineralization Pathways of Benthic Invertebrate Taxa

NASA Astrophysics Data System (ADS)

DeCorte, I. A.; Liu, Y. W.; Doss, W. C.; Ries, J. B.; Eagle, R.

2016-12-01

Ocean acidification is the result of surface ocean absorption of anthropogenic carbon dioxide emissions and endangers many marine organisms. Decreases in pH and a coupled reduction in CaCO3 saturation state have been shown to disrupt the process of biomineralization within many species of marine calcifiers. Recent studies, however, demonstrate that calcifying organisms respond in diverse ways to changes in pH and CaCO3 saturation state. We examine element ratios (including Sr/Ca, Mg/Ca, Li/Ca, and B/Ca) and boron isotope ratios (δ11B) in 7 macro-invertebrate species (blue crab, shrimp, coralline red algae, pencil urchin, purple urchin, temperate coral, and serpulid worm) and compare results to net calcification rates and experimental seawater carbonate system parameters. Correlations between seawater carbonate chemistry and the elemental compositions of biogenic calcite and aragonite vary widely and are highly taxon-specific, ranging from strongly correlated to no significant response—a finding that is consistent with mounting evidence that many marine calcifying organisms regulate the chemistry of the fluid at their site of calcification. A Rayleigh framework is used to interpret the elemental data. We then analyze δ11B of the same samples as a proxy for pH at their site of calcification. Preliminary results suggest that coralline red algae, shrimp, urchin, serpulid worm and temperate coral taxa elevate pH at the site of calcification relative to the organism's ambient seawater. We plan to utilize a multi-proxy approach to examine the biomineralization pathways that influence elemental and boron isotope fractionation during calcification and precipitation of biogenic aragonite and calcite. A better understanding of these biomineralization pathways will help us to predict the responses of benthic invertebrate taxa to ocean acidification, as well as provide insights into drivers of so-called vital effects on elemental and stable boron isotope fractionation within biogenic carbonates—thereby assessing the fidelity of these proxies for reconstructing paleo-environmental change within a diverse range of marine calcifiers.

A multi-proxy assessment of dieback causes in a Mediterranean oak species.

PubMed

Colangelo, Michele; Camarero, J Julio; Battipaglia, Giovanna; Borghetti, Marco; De Micco, Veronica; Gentilesca, Tiziana; Ripullone, Francesco

2017-05-01

Drought stress causes forest dieback that is often explained by two interrelated mechanisms, namely hydraulic failure and carbon starvation. However, it is still unclear which functional and structural alterations, related to these mechanisms, predispose to dieback. Here we apply a multi-proxy approach for the characterization of tree structure (radial growth, wood anatomy) and functioning (δ13C, δ18O and non-structural carbohydrates (NSCs)) in tree rings before and after drought-induced dieback. We aim to discriminate which is the main mechanism and to assess which variables can act as early-warning proxies of drought-triggered damage. The study was tailored in southern Italy in two forests (i.e., San Paolo (SP) and Oriolo (OR)) where declining and non-declining trees of a ring-porous tree species (Quercus frainetto Ten.) showing anisohydric behavior coexist. Both stands showed growth decline in response to warm and dry spring conditions, although the onset of dieback was shifted between them (2002 in SP and 2009 in OR). Declining trees displayed a sharp growth drop after this onset with reductions of 49% and 44% at SP and OR sites, respectively. Further, contrary to what we expected, declining trees showed a lower intrinsic water-use efficiency compared with non-declining trees after the dieback onset (with reductions of 9.7% and 5.6% at sites SP and OR, respectively), due to enhanced water loss through transpiration, as indicated by the lower δ18O values. This was more noticeable at the most drought-affected SP stand. Sapwood NSCs did not differ between declining and non-declining trees, indicating no carbon starvation in affected trees. Thus, the characterized structural and functional alterations partially support the hydraulic failure mechanism of dieback. Finally, we show that growth data are reliable early-warning proxies of drought-triggered dieback. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Global Synthesis of Common Era Hydroclimate using Water Isotope Proxies from Multiple Archives: First Results from the PAGES Iso2k Project

NASA Astrophysics Data System (ADS)

Konecky, B. L.; Partin, J. W.; Conroy, J. L.; Fischer, M.; Jones, M.; Jonkers, L.; McKay, N.; Stevenson, S.; Thompson, D. M.; Tyler, J. J.; Churakova (Sidorova), O.; Comas-Bru, L.; Dassie, E. P.; Dee, S.; DeLong, K. L.; Falster, G.; Martrat, B.

2017-12-01

Global, multi-proxy paleoclimate data syntheses for the Common Era (CE) have revealed a long-term cooling over the past millennium followed by a recent warming, with possible multi-decadal to centennial temperature variability in some regions. However, changes in atmospheric-oceanic circulation or hydroclimate have yet to be assessed on a global scale. Excellently suited to this purpose are proxies for the δ18O and δD of environmental waters found in glacier and ground ice, speleothems, corals, tree rings, and lake and marine sediments, which track common signals related to circulation and hydroclimate. Here, we utilize the new PAGES Iso2k database, a global compilation of CE δ18O and δD records, to investigate spatiotemporal variability and secular trends in global hydroclimate during the past 2 kyr. Overall, subtle but robust circulation shifts are apparent during the CE. We find preliminary evidence for secular trends in δ18O of lake water, precipitation/soil water, and seawater, with the direction and magnitude of trends varying by the type of environmental water (e.g., precipitation vs. seawater) and by region. We also find evidence for centennial-scale variations in regional δ18O and δD, for example a basin-wide Atlantic δ18Oseawater anomaly emerging during the 18th century and possible freshening of the western Pacific during the 20th century. On land, latitudinal trends in mean CE δ18Olake are consistent with present day gradients of δ18Oprecipitation, with evaporation exerting additional strong influence at mid-latitudes. In the ocean, coral δ18O in the western equatorial Pacific is found to reflect salinity rather than (or in addition to) temperature, providing potential quantitative constraints on past moisture balance from corals. We evaluate the dynamics of these spatiotemporal patterns through comparison with isotope-enabled model simulations, discuss relevant climatic inferences, and reexamine proxy interpretations.

On the relationships of 'Marmosa' formosa Shamel, 1930 (Marsupialia: Didelphidae), a phylogenetic puzzle from the Chaco of northern Argentina

USGS Publications Warehouse

Voss, Robert S.; Gardner, Afred L.; Jansa, Sharon A.

2004-01-01

The holotype and only known specimen of Marmosa formosa Shamel, a nominal species currently synonymized with Gracilinanus agilis Burmeister, is strikingly unlike any other known didelphid marsupial. Phylogenetic analyses based on nonmolecular characters and IRBP sequences suggest that formosa is either the sister-taxon of Thylamys (including Lestodelphys) or Monodelphis. Because neither alternative is strongly supported by the data at hand, and because including formosa in Thylamys or in Monodelphis would compromise the diagnosability of those taxa, a new genus?Chacodelphys?is proposed to contain it. Currently known only from northern Argentina, Chacodelphys formosa may be widely distributed in the Chaco and other adjacent Neotropical biomes.

Mapping the Proxies of Memory and Learning Function in Senior Adults with High-performing, Normal Aging and Neurocognitive Disorders.

PubMed

Lu, Hanna; Xi, Ni; Fung, Ada W T; Lam, Linda C W

2018-06-09

Memory and learning, as the core brain function, shows controversial results across studies focusing on aging and dementia. One of the reasons is because of the multi-faceted nature of memory and learning. However, there is still a dearth of comparable proxies with psychometric and morphometric portrait in clinical and non-clinical populations. We aim to investigate the proxies of memory and learning function with direct and derived measures and examine their associations with morphometric features in senior adults with different cognitive status. Based on two modality-driven tests, we assessed the component-specific memory and learning in the individuals with high performing (HP), normal aging, and neurocognitive disorders (NCD) (n = 488). Structural magnetic resonance imaging was used to measure the regional cortical thickness with surface-based morphometry analysis in a subsample (n = 52). Compared with HP elderly, the ones with normal aging and minor NCD showed declined recognition memory and working memory, whereas had better learning performance (derived scores). Meanwhile, major NCD patients showed more breakdowns of memory and learning function. The correlation between proxies of memory and learning and cortical thickness exhibited the overlapped and unique neural underpinnings. The proxies of memory and learning could be characterized by component-specific constructs with psychometric and morphometric bases. Overall, the constructs of memory are more likely related to the pathological changes, and the constructs of learning tend to reflect the cognitive abilities of compensation.

Exploring the potential of hyper-spectral imaging for the biogeochemical analysis of varved lake sediments

NASA Astrophysics Data System (ADS)

Butz, Christoph; Grosjean, Martin; Enters, Dirk; Tylmann, Wojciech

2014-05-01

Varved lake sediments have successfully been used to make inferences about past environmental and climate conditions from annual to multi-millennial scales. Among other proxies, concentrations of sedimentary photopigments have been used for temperature reconstructions. However, obtaining well calibrated annually resolved records from sediments still remains challenging. Most laboratory methods used to analyse lake sediments require physical subsampling and are destructive in the process. Hence, temporal resolution and number of data are limited by the amount of material available in the core. Furthermore, for very low sediment accumulation rates annual subsampling is often very difficult or even impossible. To address these problems we explore hyper-spectral imaging as a new method to analyse lake sediments based on their reflectance spectra in the visible and near infrared spectrum. In contrast to other fast and non-destructive methods like X-ray fluorescence, VIS/NIR reflectance spectrometry distinguishes between biogeochemical substances rather than single elements. Rein (2003) has shown that VIS-RS can be used to detect relative concentrations of sedimentary photopigments (e.g. chlorins, carotenoids) and clay minerals. This study presents an advanced approach using a hyper-spectral camera and remote sensing techniques to infer climate proxy data from reflectance spectra of varved lake sediments. Hyper-spectral imaging allows analysing an entire sediment core in a single measurement, producing a spectral dataset with very high spatial (30x30µm/pixel) and spectral resolutions (~1nm) and a higher spectral range (400-1000nm) compared to previously used spectrophotometers. This allows the analysis of data time series at sub-varve scales or spatial mapping of sedimentary substances (e.g. chlorophyll-a and diagenetic products) at very high resolution. The method is demonstrated on varved lake sediments from northern Poland showing the change of the relative concentrations of chlorin pigments within individual varve years. In a next step absolute concentrations of chlorins derived from HPLC measurements have been calibrated to the spectral data using a linear regression model. This results in a very high-resolution dataset of absolute sedimentary pigment concentrations. In a second example µXRF measurements are used to validate a spectral index for clay mineral detection.

Sedimentary Geochemical and Palynological Evidence of Late-Holocene Paleoenvironmental Change from Baradères Bay, Haiti

NASA Astrophysics Data System (ADS)

Farrington, E. J.; Lane, C.; Hawkes, A.; Donnelly, J. P.; van Hengstum, P. J.; Woodruff, J. D.; Maio, C. V.; Grochocki, K. K.; Taylor, A. K.

2017-12-01

Paleoclimate studies in equatorial regions are essential to decipher the forcing mechanisms controlling tropical precipitation dynamics. Caribbean paleoclimate records are particularly sensitive to changes in tropical convection, as they reside on the edge of the annual migrational range of the Intertropical Convergence Zone and record perturbations to many Pacific and Atlantic climate forcings. Significant sub-regional variability exists in the modern Caribbean climate and responsible forcing mechanisms on centennial to millennial timescales are largely unresolved, as reliable paleohydrological records are geographically sparse. In this study we aim to determine regional paleoenvironmental change with a specific interest in an abrupt dry period between 3200 and 2400 14C yr BP inferred from an oxygen isotope record from the nearby Lake Miragoâne, Haiti. Chronologically synchronous results from a Barbados stalagmite indicate wet conditions, which imply contrasting sub-regional hydrological responses between the northern and southern Caribbean basin. The development of multiple proximal paleoenvironmental records allows for better assessment of sub-regional Caribbean climate dynamics and the verification of existing proxy trends. We are conducting multi-proxy analyses on a 6360 14C yr, 9-meter sediment core extracted from Baradères Bay, Haiti, including loss on ignition (LOI), bulk sediment carbon (δ13C) and nitrogen (δ15N) isotope geochemistry, n-alkane hydrogen (δD) isotope geochemistry, x-ray fluorescence (XRF), and fossil pollen counts. Preliminary LOI data reveal that between 6400 and 3000 14C yr B.P. inorganic carbon ranged from 15 to 30% and organic carbon from 8 to 20%. From 3000 14C yr B.P. to present organic content decreased (9 - 13%) and inorganic carbon content increased (28 - 30%). Preliminary pollen analyses show a decrease in Rhizophora (red mangrove) pollen abundances between 3000 and 4000 14C yr BP, possibly indicating a change in estuary salinity. Additionally, XRF data show low concentrations of titanium and zircon between 5600 and 6200 14C yr BP, which may indicate a reduction in terrestrial material input. Forthcoming δD analyses of terrestrially-derived n-alkanes should help to elucidate potential paleohydrologic mechanisms responsible for the apparent changes.

Morphology, geology and geochemistry of the "Salar del Gran Bajo del Gualicho" (Rio Negro, Argentina)

USGS Publications Warehouse

Angelucci, A.; Barbieri, M.; Brodtkorb, A.; Ciccacci, S.; Civitelli, G.; De Barrio, R.; Di, Filippo M.; Fredi, P.; Friedman, I.; Lombardi, S.; Schalamuk, A.I.; Toro, B.

1996-01-01

A multidisciplinary study of the Gran Bajo del Gualicho area (Rio Negro - Argentina) was carried out; the aim was to delineate its geological and geomorphological evolution and to estabilish the genesis of salts filling the depression. Climatic conditions were analized first to individuate their role in the present morphogenetic processes; moreover the main morphological features of present landscape were examined as well as the stratigraphy of the outcropping formations, and of the Gran Bajo del Gualicho Formation in particular. Finally, a possible geomorphological evolution of the studied area was traced. Geophysical analyses allowed to estabilish that the paleosurface shaped on the crystalline basement is strongly uneven and shows evidence of the strong tectonic phases it underwent. The result of isotope analyses confirmed that the salt deposits on the Gran Bajo del Gualicho bottom were produced by fresh water evaporation, while strontium isotope ratio suggested that such waters were responsible for solubilization of more ancient evaporitic deposits.

A new lizard species of the Phymaturus patagonicus group (Squamata: Liolaemini) from northern Patagonia, Neuquén, Argentina.

PubMed

Marín, Andrea González; Pérez, Cristian Hernán Fulvio; Minoli, Ignacio; Morando, Mariana; Avila, Luciano Javier

2016-06-10

The integrative taxonomy framework allows developing robust hypotheses of species limits based on the integration of results from different data sets and analytical methods. In this work, we test a candidate species hypothesis previously suggested based on molecular data, with geometric and traditional morphometrics analyses (multivariate and univariate). This new lizard species is part of the Phymaturus patagonicus group (payuniae clade) that is distributed in Neuquén and Mendoza provinces (Argentina). Our results showed that Phymaturus rahuensis sp. nov. differs from the other species of the payuniae clade by a higher number of midbody scales, and fewer supralabials scales, finger lamellae and toe lamellae. Also, its multidimensional spaces, both based on continuous lineal variables and geometric morphometrics (shape) characters, do not overlap with those of the other species in this clade. The results of the morphometric and geometric morphometric analyses presented here, coupled with previously published molecular data, represent three independent lines of evidence that support the diagnosis of this new taxon.

Abrupt and severe 20th Century changes in the fire regimes of southeastern Australia: Evidence from a 3000 year multi-proxy analysis

NASA Astrophysics Data System (ADS)

Baker, Patrick; Mooney, Scott; Allen, Kathryn; Willersdorf, Timothy

2015-04-01

Fire is the dominant natural disturbance in southeastern Australia. For millennia it has been the driving force shaping terrestrial ecosystems in the region -- simultaneously killing vegetation and initiating regeneration across whole landscapes. Fire regimes across the region are driven by several factors including climate, vegetation, and ignition sources. Humans have been a significant contributing factor to past and present fire regimes. Prior to European settlement in the late 1700s, Aboriginal Australians used frequent, low-intensity fires to manage vegetation across much of the landscape. European settlement led to the displacement of Aboriginal communities and a shift to active fire suppression and control. This changing approach to fire management is widely believed to have initiated a fundamental shift towards extreme, high-intensity fire events as fuel loads increased. In addition, during the 20th Century prolonged periods of warm, dry conditions have occurred with greater frequency and intensity. The relative importance of climate and fire management practices on contemporary fire regimes is vigorously debated in Australia and is directly relevant to land management policies and their implementation. To put the current fire regime into historical context, we used a multi-proxy approach combining palaeo-charcoal and tree-ring analyses to assess how fire regimes have changed over the last 3000 years in the Snowy Mountains region of southeastern Australia. We found almost no evidence of high-intensity fires in the 3000 years that preceded the 20th Century. However, in the mid-20th Century there is a sudden and dramatic increase in the presence of charcoal and the pulsed establishment of trees across the landscape, suggesting a recent shift from low-intensity fires with minimal charcoal signatures to moderate- to high-intensity fires with substantial charcoal inputs. Importantly, the tree-ring data demonstrate that most of these fires were not stand-replacing and led to the establishment of multiple-age cohorts. While there is a clear shift in the fire regime in the 20th Century, the intensification of fire occurs nearly 150 years after European settlement in this area and has led to the establishment of complex, multi-aged forests across the landscape, suggesting an important interaction between fire management practices associated with European settlement and changing climatic conditions.

Climatic variability during the last deglaciation: A stalagmite-based multi-proxy record from Mawmluh cave, India

NASA Astrophysics Data System (ADS)

Huguet, C.; Munnuru Singamshetty, K.; Routh, J.; Fietz, S.; Mangini, A.; Ghosh, P.; Lone, M. A.; Rangarajan, R.; Eliasson, J.

2016-12-01

The Mawmluh cave in northeastern India, is affected by global climate patterns displaying glacial-interglacial patterns and also the Indian Summer Monsoon (ISM). Precipitation from the ISM plays a vital role for the local community and thus, understanding the driving forces of ISM fluctuations became a recent focus of a number of paleoclimate studies. Here, we used the stalagmite KM-1 from Mawmluh cave to reconstruct climate variability during the last glacial-interglacial transition from 22 to 6 ka. For the first time, molecular proxy data (TEX86 and MBT/CBT derived from isoprenoid and branched GDGTs respectively) were coupled to stable isotope records (δ13C and δ18O) and compared to other speleothem records in Asia. ISM system abruptly transition between a suppressed and active state which is associated to changes in vegetation and thus shifts in δ13C. The abrupt δ13C shift observed in our record indicate changes to wetter climate in the Holocene, which are coupled to increase in abundance of GDGTs indicating higher production and/or transfer to KM-1. The TEX86-derived temperature roughly follows the glaciation-deglaciation cycle and Holocene changes. The TEX86 results show good correspondence with the δ18O records for temperature highlighting the potential for the use of molecular proxy in speleothem based climate reconstructions. While the MBT/CBT proxy is also defined as a temperature proxy it is not coupled with δ18O patterns, and thus shows no clear temperature signal. A decoupling between MBT/CBT from soils and the connected speleothems as well as a precipitation-moisture effect on this proxy have been previously reported. In this particular case the MBT/CBT seems to be better related to precipitation-monsoon changes, and thus warrant further exploration as a complementary proxy to isotope records for monsoon strength.

Sedimentary Environment and Climate Evolution at the Northern Continental Margin of the South China Sea During the Last Glacial Cycle and Holocene

NASA Astrophysics Data System (ADS)

Tomczak, M.; Kaiser, J.; Borowka, R. K.; Chen, H.; Zhang, J.; Harff, J.; Qiu, Y.; Witkowski, A.

2014-12-01

Climate, oceanographic and sea level history during last glacial cycle (LGC) and Holocene at the NW continental margin of the South China Sea (SCS) are investigated within the SECEB project. For that purpose two sediment cores (HDQ2 & 83PC) and single-channel seismic sections were selected to serve as a proxy data source for paleoceanographic and paleoclimatic reconstructions. The sedimentary facies is interpreted by multi-proxy approaches considering micropaleontological, sedimentological and geochemical analyses. According to 14C and OSL datings, sediments of shallow water drill core HDQ2 (88.3 m) cover a time span of ca. 115 kyr BP. Seismic images of the sampling site show a series of reflectors which can be correlated with coarse layers of core HDQ2. These layers are interpreted as transgression / regression horizons. Due to the age model it is possible to correlate these horizons with the general sea level dynamics within the SCS as it is displayed in relative sea level excursions for the MIS 5 to 2 from the Sunda Shelf (Hanebuth et al. 2011). Core 83PC (8.6 m) retrieved from the continental slope provide constant record and calm environment. Therefore, this core is used as a source for data proxy for environmental reconstructions. According to δ18O and paleomagnetic analysis, a good age model which indicate age of this core to ca. 110 kyr BP was elaborated and help correlate the paleoenvironmental data with core HDQ2. Alkenones, δ18O, the Mg/Ca ratio, and microfossil proxies serve for paleo-SST curves and monsoon variability reconstructions. δ15N and δ13C indicate nutrient supply to the marine environment. Diatomological analysis outlines the environmental evolution and interrelations between their parameters during the LGC. Interpretation of seismic profiling allowed identification of submarine paleo-delta. It's anticipated that deposited sediments descent from the Hainan Island and allow correlation of the source and sink area.Hanebuth, T.J.J, Voris, H.K., Yokoyama, Y., Saito, Y., Okuno, J., 2011. Formation and fate of sedimentary depocentres on Southeast Asia's Sunda Shelf over the past sea-level cycle and biogeographic implications. Earth-Science Reviews 104, p. 92-110The project was funded by the Polish National Science Centre allocated on the basis of the decision no. DEC-2011/01/N/ST10/07708

Climatic and anthropogenic controls on Mississippi River floods: a multi-proxy palaeoflood approach

NASA Astrophysics Data System (ADS)

Munoz, S. E.; Therrell, M. D.; Remo, J. W.; Giosan, L.; Donnelly, J. P.

2017-12-01

Over the last century, many of the world's major rivers have been modified for the purposes of flood mitigation, power generation, and commercial navigation. Engineering modifications to the Mississippi River system have altered the river's sediment budget and channel morphology, but the influence of these modifications on flood risk is debated. Detecting and attributing changes in river discharge is challenging because instrumental streamflow records are often too short to evaluate the range of natural hydrological variability prior to the establishment of flood mitigation infrastructure. Here we show that multi-decadal trends of flood risk on the lower Mississippi River are strongly modulated by dynamical modes of climate variability, particularly the El Niño-Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO), but that artificial channelization has greatly amplified flood magnitudes over the last century. Our results, based on a multi-proxy reconstruction of flood frequency and magnitude spanning the last five hundred years that combines sedimentary, tree-ring, and instrumental records, reveal that the magnitude of the 100-year flood has increased by 20% over the period of record, with 75% of this increase attributed to river engineering. We conclude that the interaction of human alterations to the Mississippi River system with dynamical modes of climate variability has elevated the current flood risk to levels that are unprecedented within the last five centuries.

Quantitative trait loci analyses and RNA-seq identify genes affecting stress response in rainbow trout

USDA-ARS?s Scientific Manuscript database

Genomic analyses have the potential to impact aquaculture production traits by identifying markers as proxies for traits which are expensive or difficult to measure and characterizing genetic variation and biochemical mechanisms underlying phenotypic variation. One such trait is the response of rai...

[Munchausen syndrome by proxy].

PubMed

Goñi González, T; Martínez Roda, Maria J; de la Cerda Ojeda, F; Gómez de Terreros, I

2008-06-01

Munchausen syndrome by proxy is an illness which is very difficult to diagnose. It has a high morbidity and mortality rate. The knowledge of the characteristics of the victim and the perpetrator can be quite useful for its early recognition. The American Professional Society on the Abuse of Children, has recently brought the terms for the syndrome up to date. We look at this updating and present six cases diagnosed in our hospital, analysing their main features and comparing them with the medical literature.

Comparing Apples to Apples: Paleoclimate Model-Data comparison via Proxy System Modeling

NASA Astrophysics Data System (ADS)

Dee, Sylvia; Emile-Geay, Julien; Evans, Michael; Noone, David

2014-05-01

The wealth of paleodata spanning the last millennium (hereinafter LM) provides an invaluable testbed for CMIP5-class GCMs. However, comparing GCM output to paleodata is non-trivial. High-resolution paleoclimate proxies generally contain a multivariate and non-linear response to regional climate forcing. Disentangling the multivariate environmental influences on proxies like corals, speleothems, and trees can be complex due to spatiotemporal climate variability, non-stationarity, and threshold dependence. Given these and other complications, many paleodata-GCM comparisons take a leap of faith, relating climate fields (e.g. precipitation, temperature) to geochemical signals in proxy data (e.g. δ18O in coral aragonite or ice cores) (e.g. Braconnot et al., 2012). Isotope-enabled GCMs are a step in the right direction, with water isotopes providing a connector point between GCMs and paleodata. However, such studies are still rare, and isotope fields are not archived as part of LM PMIP3 simulations. More importantly, much of the complexity in how proxy systems record and transduce environmental signals remains unaccounted for. In this study we use proxy system models (PSMs, Evans et al., 2013) to bridge this conceptual gap. A PSM mathematically encodes the mechanistic understanding of the physical, geochemical and, sometimes biological influences on each proxy. To translate GCM output to proxy space, we have synthesized a comprehensive, consistently formatted package of published PSMs, including δ18O in corals, tree ring cellulose, speleothems, and ice cores. Each PSM is comprised of three sub-models: sensor, archive, and observation. For the first time, these different components are coupled together for four major proxy types, allowing uncertainties due to both dating and signal interpretation to be treated within a self-consistent framework. The output of this process is an ensemble of many (say N = 1,000) realizations of the proxy network, all equally plausible under assumed dating uncertainties. We demonstrate the utility of the PSM framework with an integrative multi-PSM simulation. An intermediate-complexity AGCM with isotope physics (SPEEDY-IER, (Molteni, 2003, Dee et al., in prep)) is used to simulate the isotope hydrology and atmospheric response to SSTs derived from the LM PMIP3 integration of the CCSM4 model (Landrum et al., 2012). Relevant dynamical and isotope variables are then used to drive PSMs, emulating a realistic multiproxy network (Emile-Geay et al., 2013). We then ask the following question: given our best knowledge of proxy systems, what aspects of GCM behavior may be validated, and with what uncertainties? We approach this question via a three-tiered 'perfect model' study. A random realization of the simulated proxy data (hereafter 'PaleoObs') is used as a benchmark in the following comparisons: (1) AGCM output (without isotopes) vs. PaleoObs; (2) AGCM output (with isotopes) vs. PaleoObs; (3) coupled AGCM-PSM-simulated proxy ensemble vs. PaleoObs. Enhancing model-data comparison using PSMs highlights uncertainties that may arise from ignoring non-linearities in proxy-climate relationships, or the presence of age uncertainties (as is most typically done is paleoclimate model-data intercomparison). Companion experiments leveraging the 3 sub-model compartmentalization of PSMs allows us to quantify the contribution of each sub-system to the observed model-data discrepancies. We discuss potential repercussions for model-data comparison and implications for validating predictive climate models using paleodata. References Braconnot, P., Harrison, S. P., Kageyama, M., Bartlein, P. J., Masson-Delmotte, V., Abe-Ouchi, A., Otto-Bliesner, B., Zhao, Y., 06 2012. Evaluation of climate models using palaeoclimatic data. Nature Clim. Change 2 (6), 417-424. URL http://dx.doi.org/10.1038/nclimate1456 Emile-Geay, J., Cobb, K. M., Mann, M. E., Wittenberg, A. T., Apr 01 2013. Estimating central equatorial pacific sst variability over the past millennium. part i: Methodology and validation. Journal of Climate 26 (7), 2302-2328. URL http://search.proquest.com/docview/1350277733?accountid=14749 Evans, M., Tolwinski-Ward, S. E., Thompson, D. M., Anchukaitis, K. J., 2013. Applications of proxy system modeling in high resolution paleoclimatology. Quaternary Science Reviews. URL http://adsabs.harvard.edu/abs/2012QuInt.279U.134E Landrum, L., Otto-Bliesner, B. L., Wahl, E. R., Capotondi, A., Lawrence, P. J., Teng, H., 2012. Last Millennium Climate and Its Variability in CCSM4. Journal of Climate (submitted) Molteni, F., 2003. Atmospheric simulations using a GCM with simplified physical parametrizations. I model climatology and variability in multi-decadal experiments. Climate Dynamics, 175-191

Measuring the Wage Costs of Limited English: Issues with Using Interviewer versus Self-Reports in Determining Latino Wages

ERIC Educational Resources Information Center

Hamilton, Darrick; Goldsmith, Arthur H.; Darity, William, Jr.

2008-01-01

Scholars have found that poor English proficiency is negatively associated with wages using self-reported measures. However, these estimates may suffer from misclassification bias. Interviewer ratings are likely to more accurately proxy employer assessment of worker language ability. Using self-reported and interviewer ratings from the Multi-City…

Solar wind variations in the 60-100 year period range: A review

NASA Technical Reports Server (NTRS)

Feynman, J.

1983-01-01

The evidence for and against the reality of a solar wind variation in the period range of 60-100 years is reexamined. Six data sets are reviewed; sunspot numbers, geomagnetic variations, two auroral data sets and two (14)C data sets. These data are proxies for several different aspects of the solar wind and the presence or absence of 60-100 year cyclic behavior in a particular data set does not necessarily imply the presence or absence of this variation in other sets. It was concluded that two different analyses of proxy data for a particular characteristic of the heliospheric solar wind yielded conflicting results. This conflict can be resolved only by future research. It is also definitely confirmed that proxy data for the solar wind in the ecliptic at 1 A.U. undergo a periodic variation with a period of approximately 87 years. The average amplitude and phase of this variation as seen in eleven cycles of proxy data are presented.

Exploring the usability of isotopically anomalous oxygen in bones and teeth as paleo-CO2-barometer

NASA Astrophysics Data System (ADS)

Pack, Andreas; Gehler, Alexander; Süssenberger, Annette

2013-02-01

Fluctuations in atmospheric p may have played the key role in global climate throughout Earth's history. For the quantification of past variations in atmospheric p, several geological proxy approaches and geochemical models have been developed. Here, we evaluate a new CO2 proxy approach that is based on the triple oxygen isotope composition (16O, 17O, 18O) of skeletal apatite of terrestrial mammals. Our approach utilizes the relation between an anomaly in 17O of tropospheric air O2 and atmospheric p. The anomaly is transferred from inhaled air O2 to skeletal apatite of mammals. Hence, triple oxygen isotope data of mammalian bioapatite provide information regarding p during the animal's lifetime. The approach was calibrated with a detailed mass balance model that was verified by analyses on a set of recent mammals. We evaluate the potential of this new independent terrestrial paleo-CO2 proxy in a case study including Eocene to Miocene samples. The present investigation provides promising results that are in good agreement with existing proxy- and model data. The uncertainty intrinsic to the proxy is mainly due to uncertainties in physiological parameters.

An experimental 392-year documentary-based multi-proxy (vine and grain) reconstruction of May-July temperatures for Kőszeg, West-Hungary

NASA Astrophysics Data System (ADS)

Kiss, Andrea; Wilson, Rob; Bariska, István

2011-07-01

In this paper, we present a 392-year-long preliminary temperature reconstruction for western Hungary. The reconstructed series is based on five vine- and grain-related historical phenological series from the town of Kőszeg. We apply dendrochronological methods for both signal assessment of the phenological series and the resultant temperature reconstruction. As a proof of concept, the present reconstruction explains 57% of the temperature variance of May-July Budapest mean temperatures and is well verified with coefficient of efficiency values in excess of 0.45. The developed temperature reconstruction portrays warm conditions during the late seventeenth and early eighteenth centuries with a period of cooling until the coldest reconstructed period centred around 1815, which was followed by a period of warming until the 1860s. The phenological evidence analysed here represent an important data source from which non-biased estimates of past climate can be derived that may provide information at all possible time-scales.

Holocene depositional environments and surface-level changes at Lake Fryxell, Antarctica

USGS Publications Warehouse

Whittaker, T.E.; Hall, B.L.; Hendy, C.H.; Spaulding, S.A.

2008-01-01

We report on Holocene surface-level variations of Lake Fryxell, Antarctica, as determined from multi-proxy analyses of 18 sediment cores. During this time accumulating sediments were predominantly aeolian sand with algal and carbonate laminae. Based on stratigraphy, mineralogy and diatom assemblages we suggest some carbonate laminae were deposited when lake level dropped, leading to concentration and subsequent precipitation of salts. Although lake level appears to have remained relatively stable throughout the Holocene, minor (<4.5 m below present) lowstands occurred at approximately 6400, 4700, 3800 and ??? 1600 cal. yr BP. The stability of Lake Fryxell during the Holocene contrasts with large-scale variability at other Dry Valleys lakes (eg, Lake Vanda) and with suggestions from chemical diffusion models of a near-desiccation at ???1200 cal. yr BP. The reason for the comparative stability of Lake Fryxell is uncertain, but may be the result of basin morphology and the number, aspect and proximity of meltwater sources. ?? 2008 SAGE Publications.

Diagnosing sea ice from the north american multi model ensemble and implications on mid-latitude winter climate

NASA Astrophysics Data System (ADS)

Elders, Akiko; Pegion, Kathy

2017-12-01

Arctic sea ice plays an important role in the climate system, moderating the exchange of energy and moisture between the ocean and the atmosphere. An emerging area of research investigates how changes, particularly declines, in sea ice extent (SIE) impact climate in regions local to and remote from the Arctic. Therefore, both observations and model estimates of sea ice become important. This study investigates the skill of sea ice predictions from models participating in the North American Multi-Model Ensemble (NMME) project. Three of the models in this project provide sea-ice predictions. The ensemble average of these models is used to determine seasonal climate impacts on surface air temperature (SAT) and sea level pressure (SLP) in remote regions such as the mid-latitudes. It is found that declines in fall SIE are associated with cold temperatures in the mid-latitudes and pressure patterns across the Arctic and mid-latitudes similar to the negative phase of the Arctic Oscillation (AO). These findings are consistent with other studies that have investigated the relationship between declines in SIE and mid-latitude weather and climate. In an attempt to include additional NMME models for sea-ice predictions, a proxy for SIE is used to estimate ice extent in the remaining models, using sea surface temperature (SST). It is found that SST is a reasonable proxy for SIE estimation when compared to model SIE forecasts and observations. The proxy sea-ice estimates also show similar relationships to mid-latitude temperature and pressure as the actual sea-ice predictions.

Temperature record and sapropel formation during the late Pliocene in central Mediterranean: a multi-proxy approach

NASA Astrophysics Data System (ADS)

Plancq, Julien; Grossi, Vincent; Huguet, Carme; Pittet, Bernard; Rosell-Mele, Antoni; Mattioli, Emanuela

2014-05-01

The late Pliocene (Piacenzian; 3.6-2.6 Myr) in the Mediterranean region is characterized by the deposition of organic-rich sedimentary layers named sapropels. Sapropel formation has been related to the strengthening of the precessionally-controlled African monsoon, triggering enhanced primary productivity and/or improved organic matter preservation. However, the relative importance of surface-ocean productivity versus deep-water preservation for sapropel formation remains a long standing debate among the science community. Here, we used a multi-proxy approach to characterize long-term environmental conditions and to discuss sapropel formation during the late Pliocene at Punta Grande/Punta Piccola sections (southwest Sicily). Sea and air temperatures were reconstructed using all the lipid biomarker-based temperature proxies currently available: the alkenone unsaturation index (UK'37), the tetraether index (TEX86), the Long-chain Diol Index (LDI), and the degree of methylation/cyclization of branched tetraether (MBT/CBT). Results show that sea-surface temperatures (SSTs) were relatively stable throughout the late Pliocene, but that consistent increases are recorded in most sapropel layers. SST record was then compared with variations in total organic carbon proportions, lipid biomarkers contents and nannofossil assemblages. Based on these observations, two mechanisms of formation can be inferred for each sapropel. A first series of sapropels is likely due to a better preservation of organic matter, due to the development of a thermohaline stratification of the water column and to oxygen depleted bottom waters. The second series of sapropels is more likely due to enhanced primary productivity in a non-stratified water column.

Multi-proxy Reconstructions of Deglacial Variability of Antarctic Intermediate Water Circulation in the Western Tropical Atlantic

NASA Astrophysics Data System (ADS)

Huang, K.; Oppo, D.; Curry, W. B.

2012-12-01

Reconstruction of changes in Antarctic Intermediate Water (AAIW) circulation across the last deglaciation is critical in constraining the links between AAIW and Atlantic Meridional Overturning Circulation (AMOC) and understanding how AAIW influences oceanic heat transport and carbon budget across abrupt climate events. Here we systematically establish in situ calibrations for carbonate saturation state (B/Ca), nutrient (Cd/Ca and δ13C) and watermass proxies (ɛNd) in foraminifera using multicore tops and ambient seawater samples collected from the Demerara Rise, western tropical Atlantic. Through the multi-proxy reconstructions, deglacial variability of intermediate water circulation in the western tropical Atlantic can be further constrained. The reconstructed seawater Cd record from the Demerara Rise sediment core (KNR197-3-46CDH, at 947 m water depth) over the last 21 kyrs suggests reduced presence of AAIW during the cold intervals (LGM, H1 and YD) when AMOC was reduced. Down-core B/Ca record shows elevated intermediate water Δ[CO32-] during these cold intervals, further indicating a weaker influence of AAIW in the western tropical Atlantic. The δ13C record exhibits a pronounced deglacial minimum and a clear decoupling between δ13C and Cd/Ca after the AMOC completely recovered at around 8 kyr BP. This could be due to the carbonate ion effect on benthic Cd/Ca or the influence of organic matter remineralization on benthic δ13C. A new ɛNd record for the last deglaciation will be provided to evaluate the relative proportions of southern and northern waters at this intermediate site in the western tropical Atlantic.

Ethnobotanical knowledge in rural communities of Cordoba (Argentina): the importance of cultural and biogeographical factors

PubMed Central

2009-01-01

Background The possibility to better understand the relationships within the men, the nature and their culture has extreme importance because allows the characterisation of social systems through their particular environmental perception, and provides useful tools for the development of conservation policies. Methods The present study was planned to disentangle environmental and cultural factors that are influencing the perception, knowledge and uses of edible and medicinal plants in rural communities of Cordoba (Argentina). Interviews an participant observation were conducted in nine rural communities located in three different biogeographical areas. Data about knowledge of medicinal and edible plants and sociocultural variables were obtained. Data were analysed by Principal Components Analysis (PCA). Results The analysis of data confirmed that medicinal species are widely used whereas the knowledge on edible plants is eroding. The PCA showed four groups of communities, defined by several particular combinations of sociocultural and/or natural variables. Conclusion This comprehensive approach suggests that in general terms the cultural environment has a stronger influence than the natural environment on the use of medicinal and edible plants in rural communities of Cordoba (Argentina). PMID:20003502

First genetic characterization of Fasciola hepatica in Argentina by nuclear and mitochondrial gene markers.

PubMed

Carnevale, Silvana; Malandrini, Jorge Bruno; Pantano, María Laura; Soria, Claudia Cecilia; Rodrigues-Silva, Rosângela; Machado-Silva, José Roberto; Velásquez, Jorge Néstor; Kamenetzky, Laura

2017-10-15

Fasciola hepatica is a trematode showing genetic variation among isolates from different regions of the world. The objective of this work was to characterize for the first time F. hepatica isolates circulating in different regions of Argentina. Twenty-two adult flukes were collected from naturally infected bovine livers in different areas from Argentina and used for DNA extraction. We carried out PCR amplification and sequence analysis of the ribosomal internal transcribed spacer 1 (ITS1), mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunits 4 and 5 (nad4 and nad5) and mitochondrial cytochrome c oxidase subunit I (cox1) genes as genetic markers. Phylogenies were reconstructed using maximum parsimony algorithm. A total of 6 haplotypes were found for cox1, 4 haplotypes for nad4 and 3 haplotypes for nad5. The sequenced ITS1 fragment was identical in all samples. The analyzed cox1 gene fragment is the most variable marker and is recommended for future analyses. No geographic association was found in the Argentinean samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Reptiles of Chubut province, Argentina: richness, diversity, conservation status and geographic distribution maps.

PubMed

Minoli, Ignacio; Morando, Mariana; Avila, Luciano Javier

2015-01-01

An accurate estimation of species and population geographic ranges is essential for species-focused studies and conservation and management plans. Knowledge of the geographic distributions of reptiles from Patagonian Argentina is in general limited and dispersed over manuscripts from a wide variety of topics. We completed an extensive review of reptile species of central Patagonia (Argentina) based on information from a wide variety of sources. We compiled and checked geographic distribution records from published literature and museum records, including extensive new data from the LJAMM-CNP (CENPAT-CONICET) herpetological collection. Our results show that there are 52 taxa recorded for this region and the highest species richness was seen in the families Liolaemidae and Dipsadidae with 31 and 10 species, respectively. The Patagónica was the phytogeographic province most diverse in species and Phymaturus was the genus of conservation concern most strongly associated with it. We present a detailed species list with geographical information, richness species, diversity analyses with comparisons across phytogeographical provinces, conservation status, taxonomic comments and distribution maps for all of these taxa.

Reptiles of Chubut province, Argentina: richness, diversity, conservation status and geographic distribution maps

PubMed Central

Minoli, Ignacio; Morando, Mariana; Avila, Luciano Javier

2015-01-01

Abstract An accurate estimation of species and population geographic ranges is essential for species-focused studies and conservation and management plans. Knowledge of the geographic distributions of reptiles from Patagonian Argentina is in general limited and dispersed over manuscripts from a wide variety of topics. We completed an extensive review of reptile species of central Patagonia (Argentina) based on information from a wide variety of sources. We compiled and checked geographic distribution records from published literature and museum records, including extensive new data from the LJAMM-CNP (CENPAT-CONICET) herpetological collection. Our results show that there are 52 taxa recorded for this region and the highest species richness was seen in the families Liolaemidae and Dipsadidae with 31 and 10 species, respectively. The Patagónica was the phytogeographic province most diverse in species and Phymaturus was the genus of conservation concern most strongly associated with it. We present a detailed species list with geographical information, richness species, diversity analyses with comparisons across phytogeographical provinces, conservation status, taxonomic comments and distribution maps for all of these taxa. PMID:25931966

Tuning History in Latin America

ERIC Educational Resources Information Center

Velázquez Albo, Marco

2017-01-01

This article analyses the development and achievements of the area of History in the Tuning-Latin America Project from its launch in 2004 to its completion in 2013. Through two phases and nine general meetings, academics from Argentina, Brazil, Chile, Colombia, Costa Rica, Cuba, Guatemala, Mexico and Peru, along with academics from Spain, Portugal…

Education Policies and Organizational Structures in Argentinian Secondary Schools

ERIC Educational Resources Information Center

Vicente, María Eugenia

2016-01-01

Purpose: The purpose of this paper is to review the link between public education policies and institutional practices in Argentina throughout history and today. Design/methodology/approach: The methodology used is in line with socio-educational management studies oriented to analyse educational practices qualitatively from an institutional…

Examination of multi-model ensemble seasonal prediction methods using a simple climate system

NASA Astrophysics Data System (ADS)

Kang, In-Sik; Yoo, Jin Ho

2006-02-01

A simple climate model was designed as a proxy for the real climate system, and a number of prediction models were generated by slightly perturbing the physical parameters of the simple model. A set of long (240 years) historical hindcast predictions were performed with various prediction models, which are used to examine various issues of multi-model ensemble seasonal prediction, such as the best ways of blending multi-models and the selection of models. Based on these results, we suggest a feasible way of maximizing the benefit of using multi models in seasonal prediction. In particular, three types of multi-model ensemble prediction systems, i.e., the simple composite, superensemble, and the composite after statistically correcting individual predictions (corrected composite), are examined and compared to each other. The superensemble has more of an overfitting problem than the others, especially for the case of small training samples and/or weak external forcing, and the corrected composite produces the best prediction skill among the multi-model systems.

Psychometric evaluation and wording effects on the Chinese version of the parent-proxy Kid-KINDL.

PubMed

Lee, Chih-Ting; Lin, Chung-Ying; Tsai, Meng-Che; Strong, Carol; Lin, Yi-Ching

2016-09-05

The pediatric quality of life (QoL) questionnaire, the child-rated Kid-KINDL, has wording effects. However, no studies have examined for its parallel questionnaire, the parent-proxy Kid-KINDL. This study aimed to examine the psychometric properties and wording effects of the parent-proxy Kid-KINDL. Parents with 8- to 12-year-old children (n = 247) completed the parent-proxy Kid-KINDL, 83 of them completed it again 7-14 days later, and 241 of their children completed the child-rated Kid-KINDL. Internal consistency was examined using Cronbach's α; test-retest reliability and concurrent validity, using Pearson correlation coefficients (r); construct validity and wording effects, using confirmatory factor analyses (CFAs). The internal consistency of the parent-proxy Kid-KINDL total score was acceptable (α = .86). Test-retest reliability (r = .33-.60) and concurrent validity (r = .27-.42) were acceptable or nearly acceptable for all subscales and the total score. The CFA models simultaneously accounting for QoL traits and wording effects had satisfactory fit indices, and outperformed the model accounting only for QoL traits. However, four subscales had unsatisfactory internal consistency, which might be attributable to wording effects. When children are unable to complete a QoL questionnaire, the parent-proxy Kid-KINDL can substitute with all due cautions to wording effects and inconsistent reliability among different raters.

Ash resuspension related to the 2011-2012 Cordón Caulle eruption, Chile, in a rural community of Patagonia, Argentina

NASA Astrophysics Data System (ADS)

Forte, Pablo; Domínguez, Lucia; Bonadonna, Costanza; Gregg, Chris E.; Bran, Donaldo; Bird, Deanne; Castro, Jonathan M.

2018-01-01

The 2011-2012 Cordón Caulle eruption emitted about 1 km3 of rhyodacitic tephra. Dominant westerly winds in the region caused most of the primary tephra to deposit in neighboring Argentina. In addition to the impact of widespread dispersal and fallout of primary tephra during the eruption, Argentina was also significantly affected by remobilization of the primary ash even several years after the climactic phase of the eruption. In this mixed methods study, we combine aspects of natural and social sciences to characterize the ash resuspension events associated with the 2011-2012 Cordón Caulle deposits and assess the impacts on the Argentinian farming community of Ingeniero Jacobacci in the Patagonian Steppe. Our findings show the primary importance of wind, rainfall and ash availability in controlling the occurrence and persistence of ash resuspension events. The role played by these variables was also reflected in the seasonal distribution of events observed. Regarding the impacts, our results complement those of earlier studies and demonstrate that ash resuspension events can exacerbate the negative impact of primary tephra fallout events from the time of deposition to many years after the eruption. Only after five years has the environment and the farming community begun to show signs of recovery. Our findings also highlight the importance of assessing ash resuspension events in multi-hazard scenarios involving volcanic and hydrometeorologic hazards.

Construction and first atmospheric observations of a high spectral resolution lidar system in Argentina in the frame of a trinational Japanese-Argentinean-Chilean collaboration

NASA Astrophysics Data System (ADS)

Papandrea, S.; Jin, Y.; Ristori, P.; Otero, L.; Nishizawa, T.; Mizuno, A.; Sugimoto, N.; Quel, E.

2016-05-01

Atmospheric monitoring stations are being developed in Argentina. The most important targets are volcanic ashes, desert aerosols in particular Patagonian dust and biomass burning aerosols. Six stations deployed in the Patagonian Region and Buenos Aires have lidar systems, sun photometers integrated to the AERONET/NASA monitoring network, in situ optical particle analyzers, four solar radiation sensors (pyranometer, UVA, UVB and GUV), and meteorological equipment. The stations are in the main international airports of the Regions (San Carlos de Bariloche, Comodoro Rivadavia, Neuquén, Rio Gallegos) and in Buenos Aires (Aeroparque Jorge Newbery and at CEILAP/CITEDEF). CEILAP and the National Institute of Environmental Studies (NIES) at Tsukuba, Japan developed the first iodine cell-based high spectral resolution lidar (HSRL) in Argentina to add in the lidar network. We upgraded the standard CEILAP multi-wavelength Raman lidar adding the laser frequency tuning system and the 532 iodine-filtered channel at the reception to built the HSRL. HSRL will provide daytime and nighttime direct observation of the aerosol and cloud optical properties (backscatter and extinction) without the pre-assumption of the lidar ratio. This work shows the design and construction of the first Argentinean HSRL. We also show the first lidar observations done in the country with this kind of lidar.

An ordination of life histories using morphological proxies: capital vs. income breeding in insects.

PubMed

Davis, Robert B; Javoiš, Juhan; Kaasik, Ants; Õunap, Erki; Tammaru, Toomas

2016-08-01

Predictive classifications of life histories are essential for evolutionary ecology. While attempts to apply a single approach to all organisms may be overambitious, recent advances suggest that more narrow ordination schemes can be useful. However, these schemes mostly lack easily observable proxies of the position of a species on respective axes. It has been proposed that, in insects, the degree of capital (vs. income) breeding, reflecting the importance of adult feeding for reproduction, correlates with various ecological traits at the level of among-species comparison. We sought to prove these ideas via rigorous phylogenetic comparative analyses. We used experimentally derived life-history data for 57 species of European Geometridae (Lepidoptera), and an original phylogenetic reconstruction. The degree of capital breeding was estimated based on morphological proxies, including relative abdomen size of females. Applying Brownian-motion-based comparative analyses (with an original update to include error estimates), we demonstrated the associations between the degree of capital breeding and larval diet breadth, sexual size dimorphism, and reproductive season. Ornstein-Uhlenbeck model based phylogenetic analysis suggested a causal relationship between the degree of capital breeding and diet breadth. Our study indicates that the gradation from capital to income breeding is an informative axis to ordinate life-history strategies in flying insects which are affected by the fecundity vs. mobility trade off, with the availability of easy to record proxies contributing to its predictive power in practical contexts. © 2016 by the Ecological Society of America.

Older adults’ attitudes toward noncompetent subjects participating in Alzheimers research

PubMed Central

Karlawish, Jason; Rubright, Jonathan; Casarett, David; Cary, Mark; TenHave, Thomas; Sankar, Pamela

2008-01-01

Objective Since research that enrolls noncompetent patients with Alzheimers disease and does not present potential benefit to subjects is the source of substantial ethical controversy, we assessed willingness to have a proxy for research decision making, and, for each of two Alzheimers disease biomarker studies (minimal risk blood draw and a greater than minimal risk blood draw and lumbar puncture), willingness to grant an advance consent, and willingness to grant a proxy leeway over advance consent. Methods Face to face survey of 538 persons 65 and over who resided in the Southeastern Pennsylvania region Results The majority 83% (445/538) granted advance consent to a blood draw study and nearly half to a blood draw plus lumbar puncture 259 (48%). Most persons (96%) were willing to identify a proxy for research decision making and most were willing to grant their proxy leeway over their advance consent: blood draw 434 (81%), and 375 (70%) blood draw plus lumbar puncture. Combining the preferences for advance consent and leeway, the proportion who would permit being enrolled in the blood draw and spinal fluid sample studies were, respectively, 92% (497/538) and 75% (404/538). Multi-variate models showed that willingness to be enrolled in research was most strongly associated with a favorable attitude about biomedical research. Conclusions Older adults generally support enrolling noncompetent persons with Alzheimers disease into research that does not present a benefit to subjects. Willingness to grant their proxy leeway over advance consent and a favorable attitude about biomedical research substantially explain this willingness. PMID:18923066

Environmental and Physiological Influences on the TEX86 Proxy: Results from Continuous Culture Studies and Stable Carbon Isotope Analyses

NASA Astrophysics Data System (ADS)

Pearson, A.; Hurley, S.; Elling, F. J.; Koenneke, M.; Santoro, A. E.; Buchwald, C.; Wankel, S. D.; Hinrichs, K. U.; Zhang, Y.; Shah Walter, S. R.

2015-12-01

Membrane lipids of marine Archaea - known as GDGTs - are the basis of the TEX86 sea surface temperature (SST) paleoproxy. GDGTs are ubiquitous in marine sediments, and their broad distribution and high preservation potential have led to an ever-increasing use of TEX86. The planktonic Thaumarchaeota that are believed to be the major sources of GDGTs to marine sediments are autotrophic nitrifiers, assimilating carbon directly from dissolved CO2. Therefore the δ13C values of GDGTs additionally provide information about the DIC system and paleoproductivity. However, as for all biological proxies, understanding the physiology and biochemistry of the responsible organisms is essential to understanding how the proxies work. From this perspective, the TEX86-SST proxy is uniquely perplexing: How is it possible that multiple approaches to calibration show a good correlation between TEX86 and SSTs, when maximum activity of Thaumarchaeota is near and below the base of the photic zone? Here we show data from two studies that help address this question. Analyses of GDGT δ13C values show that the dominant GDGT flux to sediments is not from the sea surface. The data are measured on intact GDGTs purified by orthogonal dimensions of HPLC, followed by measurement of δ13C values on a Spooling Wire Microcombustion (SWiM)-IRMS with 1σ precision of ±0.2‰ and accuracy of ±0.3‰. Using this approach, we confirm that GDGTs, generally around -19.0‰ to -18.5‰, are isotopically "heavy" compared to other marine lipids, and that crenarchaeol in particular is a good tracer of water column GDGT export. In parallel, we investigated the mechanistic underpinning of the TEX86 proxy using isothermal culture studies of the ammonia-oxidizing thaumarchaeon Nitrosopumilus maritimus SCM1 to explore the relationship between TEX86 and growth conditions. Evidence suggests that growth rate and electron donor supply are important controls on GDGT ratios and that TEX86 scales with the in-situ rate of nitrification. Constraining the physiological basis of the TEX86 proxy and the mechanism by which this signal is transported to the sedimentary record is crucial to the proxy's application to ancient environments.

Spatio-temporal variability of Arctic summer temperatures over the past 2 millennia

NASA Astrophysics Data System (ADS)

Werner, Johannes P.; Divine, Dmitry V.; Charpentier Ljungqvist, Fredrik; Nilsen, Tine; Francus, Pierre

2018-04-01

In this article, the first spatially resolved and millennium-length summer (June-August) temperature reconstruction over the Arctic and sub-Arctic domain (north of 60° N) is presented. It is based on a set of 44 annually dated temperature-sensitive proxy archives of various types from the revised PAGES2k database supplemented with six new recently updated proxy records. As a major advance, an extension of the Bayesian BARCAST climate field (CF) reconstruction technique provides a means to treat climate archives with dating uncertainties. This results not only in a more precise reconstruction but additionally enables joint probabilistic constraints to be imposed on the chronologies of the used archives. The new seasonal CF reconstruction for the Arctic region can be shown to be skilful for the majority of the terrestrial nodes. The decrease in the proxy data density back in time, however, limits the analyses in the spatial domain to the period after 750 CE, while the spatially averaged reconstruction covers the entire time interval of 1-2002 CE.The centennial to millennial evolution of the reconstructed temperature is in good agreement with a general pattern that was inferred in recent studies for the Arctic and its subregions. In particular, the reconstruction shows a pronounced Medieval Climate Anomaly (MCA; here ca. 920-1060 CE), which was characterised by a sequence of extremely warm decades over the whole domain. The medieval warming was followed by a gradual cooling into the Little Ice Age (LIA), with 1766-1865 CE as the longest centennial-scale cold period, culminating around 1811-1820 CE for most of the target region.In total over 600 independent realisations of the temperature CF were generated. As showcased for local and regional trends and temperature anomalies, operating in a probabilistic framework directly results in comprehensive uncertainty estimates, even for complex analyses. For the presented multi-scale trend analysis, for example, the spread in different paths across the reconstruction ensemble prevents a robust analysis of features at timescales shorter than ca. 30 years. For the spatial reconstruction, the benefit of using the spatially resolved reconstruction ensemble is demonstrated by focusing on the regional expression of the recent warming and the MCA. While our analysis shows that the peak MCA summer temperatures were as high as in the late 20th and early 21st centuries, the spatial coherence of extreme years over the last decades of the reconstruction (1980s onwards) seems unprecedented at least back until 750 CE. However, statistical testing could not provide conclusive support of the contemporary warming to exceed the peak of the MCA in terms of the pan-Arctic mean summer temperatures: the reconstruction cannot be extended reliably past 2002 CE due to lack of proxy data and thus the most recent warming is not captured.

Compression-cuticle relationship of seed ferns: Insights from liquid-solid states FTIR (Late Palaeozoic-Early Mesozoic, Canada-Spain-Argentina)

USGS Publications Warehouse

Zodrow, E.L.; D'Angelo, J. A.; Mastalerz, Maria; Keefe, D.

2009-01-01

Cuticles have been macerated from suitably preserved compressed fossil foliage by Schulze's process for the past 150 years, whereas the physical-biochemical relationship between the "coalified layer" with preserved cuticle as a unit has hardly been investigated, although they provide complementary information. This relationship is conceptualized by an analogue model of the anatomy of an extant leaf: "vitrinite (mesophyll) + cuticle (biomacropolymer) = compression". Alkaline solutions from Schulze's process as a proxy for the vitrinite, are studied by means of liquid-solid states Fourier transform infrared spectroscopy (FTIR). In addition, cuticle-free coalified layers and fossilized cuticles of seed ferns mainly from Canada, Spain and Argentina of Late Pennsylvanian-Late Triassic age are included in the study sample. Infrared data of cuticle and alkaline solutions differ which is primarily contingent on the mesophyll +biomacropolymer characteristics. The compression records two pathways of organic matter transformation. One is the vitrinized component that reflects the diagenetic-post-diagenetic coalification history parallel with the evolution of the associated coal seam. The other is the cuticle that reflects the sum-total of evolutionary pathway of the biomacropolymer, its monomeric, or polymeric fragmentation, though factors promoting preservation include entombing clay minerals and lower pH conditions. Caution is advised when interpreting liquid-state-based FTIR data, as some IR signals may have resulted from the interaction of Schulze's process with the cuticular biochemistry. A biochemical-study course for taphonomy is suggested, as fossilized cuticles, cuticle-free coalified layers, and compressions are responses to shared physicogeochemical factors. ?? 2009 Elsevier B.V. All rights reserved.

The ecology of anemia: Anemia prevalence and correlated factors in adult indigenous women in Argentina.

PubMed

Goetz, Laura G; Valeggia, Claudia

2017-05-06

The Toba/Qom of Namqom are an indigenous community native to the Gran Chaco region of northern Argentina. Historically seminomadic foragers, the diet of peri-urban community members has rapidly changed from high-protein, high-fiber to hypercaloric, processed. This study aims to understand the impact of this nutritional transition on aspects of women's health by exploring the relationship between prevalence of anemia and current diet composition, place of birth, and reproductive history. We measured the capillary hemoglobin (Hb) levels of 153 adult women. Each participant was also given two interviews characterizing reproductive history and a 24-hour food recall. The average Hb level was 12.6 g/dL (range 5.8-15.7 g/dL). In our sample, 28% of participants were anemic and 31% were borderline anemic. Iron and vitamin C consumption were negatively associated with Hb levels. Body mass index was marginally associated with Hb levels. Being born in a peri-urban setting, a proxy for early Westernized diet was associated with higher risk of anemia, suggesting developmental experience may play a role. Pregnant and lactating women had lower Hb levels than menstruating and menopausal women. Age, height, parity, and age at first pregnancy were not found to be statistically significant predictors of anemia. Iron deficiency represents a serious health concern for women, particularly pregnant ones. Our results suggest that both past and current nutritional ecology variables may be associated with the risk of anemia. These findings inform public health interventions, since reproductive history may be more difficult to modify than current diet. © 2017 Wiley Periodicals, Inc.

Multi-proxy analyses of geo-bio-archives - a key to reconstruct major environmental and ecological changes in the Ephesia, W Turkey, during the last eight millennia

NASA Astrophysics Data System (ADS)

Stock, Friederike; Knipping, Maria; Pint, Anna; Krichel, Marc; Schwarzbauer, Jan; Dsikowitzky, Larissa; Brückner, Helmut

2016-04-01

This interdisciplinary geoarchaeological research in the environs of the ancient city of Ephesus (W Turkey) focuses on (i) Holocene landscape reconstruction along with sea-level changes, and (ii) human impact on landscape evolution. More than 200 sediment cores were retrieved from geo-bio-archives and analysed with a multi-proxy approach (geochemical, sedimentological, microfaunal, palynological, and parasitological methods). The Holocene palaeogeographic changes in the embayment of the Küçük Menderes (Kaystros) on the Aegean coast of Turkey with the famous ancient city of Ephesus are counted amongst the most dramatic ones in the Mediterranean. About seven millennia ago, the maximum marine transgression filled the Küçük Menderes graben up to 20 km inland. Since then, the coastline has continuously shifted westwards due to the progradation of the deltas of this river and its tributaries. Besides other natural factors, like sea level fluctuations and tectonics, the speed of delta progradation was mainly governed by the riverine sediment load, which, in turn, was very much dependent on the human impact on the vegetation cover of the drainage basins. The sedimentation rates confirm this assumption: While low rates occurred between the 5th and the 1st millennia BC (up to 1 mm/year), much higher rates (4 - 30 mm/year) can be calculated thereafter. In response to these dramatic environmental changes, human settlements and their harbours had to be relocated several times from the 1st millennium BC onwards. The Koressos harbour and the Roman harbour were important hubs for commerce with the islands in the Aegean Sea. The nowadays silted-up harbour basins are valuable geo-bio-archives. The Roman harbours inventory shows high heavy metal concentrations (lead, copper), fruit tree pollen and eggs of intestinal parasites from the 1st millennium BC until the 7th century AD, as evidence of intensive human impact during that period of time. The occurrence of organic compounds (abietane, retene, loliolode and β-cyclocitral originating, e.g., from natural resins, tar and bitumen) also correlate with the intensive use of the harbour. In contrast, the lake and swamps of Belevi, located 14 km upstream of Ephesus, represent a geo-bio-archive with a quasi-natural sedimentation. However, even there the palynological analysis clearly reveals settlement activities already since the 7th millennium BC. The proof of the Santorini tephra of 1630 BC is an excellent marker horizon; it is the first time that this ash was detected in the environs of Ephesus.

A high-resolution Holocene Asian Monsoon record from a Tibetan lake-Peiku Co

NASA Astrophysics Data System (ADS)

Du, M.; Ricketts, R. D.; Colman, S.; Werne, J. P.

2010-12-01

Recent studies on Tibetan lakes have demonstrated the great potential of lake sediments as archives of climate variations in this region. We present a high-resolution multi-proxy record from a closed-basin Tibetan lake—Peiku Co (4595m a.s.l., 28°55’ N, 85°35’E). A 5.5-meter-long UwiTec core (PC07-1B) provides a record extending back to ~22,000 cal years B.P., based on 14C AMS dating. Multi-proxy analyses, including high-resolution magnetic susceptibility, bulk density, elemental composition (ITRAX X-ray Fluorescence Core Scanner), and carbonate content have been carried out to compare to other paleoenvironmental records from the Tibetan Plateau. Furthermore, microbial lipids have been measured to test the applicability of GDGT-based temperature reconstructions (TEX86 and MBT/CBT). The record from Peiku Co captures the climate transition out of the last glacial period. A significant transition to warmer and wetter condition is indicated around 14,500 cal years B.P., possibly attributed to the strengthening of the summer monsoon, which is consistent with the monsoon records from Lake Qinghai. The switch to colder conditions between 12,500 and 11,500 cal years B.P. could be correlated with the Younger Dryas. The early and mid-Holocene is marked by an increase in monsoon precipitation, yet the overall trend is interrupted by two short periods of decreasing precipitation around 7000 and 5000 cal years B.P., as seen in other published records across the Asian monsoon areas. The GDGT indices are employed for temperature reconstruction. The samples from Peiku Co varied widely in BIT indices with values ranging from 0.23 to 0.88, with an average of 0.65. The high BIT values suggest this lake received significant terrestrial organic matter input, which probably respond to rainfall variations. The MBT/CBT-based temperature from the core-top is -3.2 °C, slightly higher than the measured MAAT (-4°C) on the Tibetan Plateau, but statistically the same within error of the current calibration. The core top sample yields a CBT-derived pH of 8.7, which broadly agrees with soil pH values measured on the Tibetan Plateau. Additional 210Pb and 14C dates and compound-specific isotope analyses will also be used to provide further information on the vegetation history and hydrological conditions in this area.

Structural Assimilation Revisited: Mexican-Origin Nativity and Cross-Ethnic Primary Ties

ERIC Educational Resources Information Center

Brown, Susan K.

2006-01-01

Classical assimilation theory postulates that over time, members of immigrant groups will develop more primary ties with native members of the host society. However, lack of data has led most research to rely on the study of either spatial mobility or other secondary variables as proxies of primary ties. Using data from the Multi-City Study of…

A multi-proxy climatic record from the central Tengger Desert, southern Mongolian Plateau: Implications for the aridification of inner Asia since the late Pliocene

NASA Astrophysics Data System (ADS)

Li, Zaijun; Wang, Fei; Wang, Xin; Li, Baofeng; Chen, Fahu

2018-07-01

Aridification of the Asian interior is one of the most significant paleoenvironmental events during the Cenozoic. However, continuous paleoclimatic records from desert interiors are scarce because of the lack of outcrops, erosion and discontinuous sediment accumulation. Here we report a multi-proxy climatic record for the last ∼3.55 Ma from paleomagnetically-dated drilling core WEDP01 from the central Tengger Desert, which is one of the most important sediment source areas for Northern Hemisphere atmospheric dust and the Chinese Loess Plateau. Analysis of grain-size components indicates the onset of continuous dust deposition at 2.6 Ma and desert formation at 0.9 Ma. In addition, analysis of major element content and sediment color reveals a stepwise process of increasing aridification and significant cooling in the Tengger Desert area. Simultaneous aridification events in northwest China during the Quaternary were probably induced by the uplift of the Tibetan Plateau. Northern Hemisphere glaciation may have been another important factor for Asian aridification; meanwhile, the increased dust emission from sources such as the Tengger Desert may provide a positive feedback mechanism for global cooling.

Indications of a pan-hemispheric bi-partition of the Younger Dryas Stadial from Lake Suigetsu, Japan

NASA Astrophysics Data System (ADS)

Schlolaut, Gordon; Brauer, Achim; Nakagawa, Takeshi; Lamb, Henry; Marshall, Michael; Kato-Saito, Megumi; Staff, Richard; Bronk Ramsey, Christopher; Bryant, Charlotte

2016-04-01

The Younger Dryas Stadial marks the final succession of climatic fluctuations of the last Glacial. Whilst well studied in records from Europe and Greenland, few high resolution records are available from East Asia. Here we present a high resolution, multi-proxy study of the Lake Suigetsu (Japan) sediments using the 'SG06' composite profile. Utilising microfacies, μXRF, pollen and diatom analysis we characterise changes occurring in the timeframe corresponding to the Younger Dryas Stadial. Firstly, our results show that the climatic equivalent of the Younger Dryas at Lake Suigetsu shows no major lead or lag in comparison to records from the North Atlantic region, which was postulated by an earlier project on the Suigetsu sediments ('SG93'). Reason for this disagreement between the SG06 and SG93 core is that the SG93 core/chronology was compromised by gaps between individual cores and varve count uncertainties. Furthermore, some of the analysed proxies from the SG06 core show a sub-division of the Younger Dryas Stadial. The timing of this sub-division is similar to the bi-partition of the Younger Dryas Stadial observed in a number of European records (e.g. Lane et al., 2013). This bi-partition was related to a northward shift of the westerly wind jet in the North Atlantic region. Our findings imply that the underlying climatic mechanism operated on a hemispheric rather than just on a regional scale. References: Lane et al. 2013, Volcanic ash reveals time-transgressive abrupt climate change during the Younger Dryas, Geology 41, 1251-1254

Late Quaternary high resolution micropaleontological and sedimentological records in the Gulf of Cadiz.

NASA Astrophysics Data System (ADS)

Balestra, B.; Ducassou, E.; Zarikian, C.; Bout-Roumazeilles, V.; Flores, J. A.; Paytan, A.

2017-12-01

We present preliminary micropaleontological and sedimentological data from IODP Site U1390 (Expedition 339), located in the central middle slope of the Gulf of Cadiz, since the last glaciation. This site has been targeted for reconstruction of regional paleo-circulation as it shows particularly high sedimentation rates, throughout the Holocene and the Last Glacial Maximum (LGM). We use micropaleontological and sedimentological proxies to understand the bottom current variations through time and the ecological conditions at the sea surface (planktonic foraminifer, pteropod and nannofossil assemblages), and the sea bottom (ostracod assemblages). Eleven samples, chosen at transitions of planktonic foraminifer assemblages, have been dated by AMS radiocarbon analyses. Preliminary results from benthic ostracod assemblages show variations in bottom water ventilation and food supply. Planktonic foraminifer assemblages clearly show the well-known cold events of this period such as the Younger Dryas and Heinrich stadial associated to coarser sediment, and warmer phases such as the Bölling-Allerød associated to muddy sediment. Other bio-events within the Holocene period are also recorded. The preservation of the coccolithophore assemblages is good to moderate. Coccolith abundances (expressed in coccoliths/gr of sediment) show higher values during the Holocene and generally are like assemblages previously reported for the same area. Implications for characterization of the Holocene, the last termination and LGM ecological conditions at high resolution and their potential fluctuations (i.e. amplitude and magnitude) under the influence of the lower core of the Mediterranean Outflow Water (MOW), with this multi proxy approach based on sedimentological, and paleontological data will be discussed.

Palaeobathymetric Interpretations using Foraminiferal Data from the North-west Continental Shelf off Western Australia, IODP Expedition 356

NASA Astrophysics Data System (ADS)

Mamo, B. L.; Renema, W.; Auer, G.; Groeneveld, J.; Gallagher, S. J.; Fulthorpe, C.; Bogus, K.; Expedition 356 Scientists, I.

2016-12-01

In 2015, Integrated Ocean Discovery Program Expedition 356 drilled along the passive margin off the West Australian coast to investigate the history of the Indonesian Throughflow (ITF) and its integral role in the development of global thermohaline circulation and climate. Throughout the expedition, a suite of foraminiferal analyses were employed to assess stratigraphy and benthic environments. Planktic foraminifera were primarily used for biostratigraphy and an incredibly diverse benthic fauna ( 260 species) yielded information regarding palaeobathymetric settings and variable conditions at the sediment-water interface. Benthic foraminiferal biofacies are particularly sensitive to changes in environmental conditions and have rapid turnover making them ideal proxies for monitoring physical and chemical changes in marine environments. When these data are combined with a multi-proxy approach incorporating lithostratigraphic and other microfossil data, a robust understanding of past environments can be realised. Stretching from the Northern Carnarvon Basin north to the Roebuck Basin, several distinct biofacies were isolated at sites U1461-U1464 that reveal an array of marine settings and events that span from the Miocene through to the Pleistocene. These features include water depths ranging from Miocene shallows (including larger benthic foraminifera) to Pliocene bathyal depths ( 1000 m), the occurrence of key indicator species for both the Leeuwin Current and the West Pacific Warm Pool (Asterorotalia and Pseudorotalia), and episodes of downslope sediment transport. Here we present the main isolated biofacies, their associated lithofacies and their implications for reconstructing fluctuating sea-level, thermohaline circulation and sediment transport in a changing marine landscape.

Spring temperature variability and eutrophication history inferred from sedimentary pigments in the varved sediments of Lake Żabińskie, north-eastern Poland, AD 1907-2008

NASA Astrophysics Data System (ADS)

Amann, Benjamin; Lobsiger, Simon; Fischer, Daniela; Tylmann, Wojciech; Bonk, Alicja; Filipiak, Janusz; Grosjean, Martin

2014-12-01

Varved lake sediments are excellent natural archives providing quantitative insights into climatic and environmental changes at very high resolution and chronological accuracy. However, due to the multitude of responses within lake ecosystems it is often difficult to understand how climate variability interacts with other environmental pressures such as eutrophication, and to attribute observed changes to specific causes. This is particularly challenging during the past 100 years when multiple strong trends are superposed. Here we present a high-resolution multi-proxy record of sedimentary pigments and other biogeochemical data from the varved sediments of Lake Żabińskie (Masurian Lake District, north-eastern Poland, 54°N-22°E, 120 m a.s.l.) spanning AD 1907 to 2008. Lake Żabińskie exhibits biogeochemical varves with highly organic late summer and winter layers separated by white layers of endogenous calcite precipitated in early summer. The aim of our study is to investigate whether climate-driven changes and anthropogenic changes can be separated in a multi-proxy sediment data set, and to explore which sediment proxies are potentially suitable for long quantitative climate reconstructions. We also test if convoluted analytical techniques (e.g. HPLC) can be substituted by rapid scanning techniques (visible reflectance spectroscopy VIS-RS; 380-730 nm). We used principal component analysis and cluster analysis to show that the recent eutrophication of Lake Żabińskie can be discriminated from climate-driven changes for the period AD 1907-2008. The eutrophication signal (PC1 = 46.4%; TOC, TN, TS, Phe-b, high TC/CD ratios total carotenoids/chlorophyll-a derivatives) is mainly expressed as increasing aquatic primary production, increasing hypolimnetic anoxia and a change in the algal community from green algae to blue-green algae. The proxies diagnostic for eutrophication show a smooth positive trend between 1907 and ca 1980 followed by a very rapid increase from ca. 1980 ± 2 onwards. We demonstrate that PC2 (24.4%, Chl-a-related pigments) is not affected by the eutrophication signal, but instead is sensitive to spring (MAM) temperature (r = 0.63, pcorr < 0.05, RMSEP = 0.56 °C; 5-yr filtered). Limnological monitoring data (2011-2013) support this finding. We also demonstrate that scanning visible reflectance spectroscopy (VIS-RS) data can be calibrated to HPLC-measured chloropigment data and be used to infer concentrations of sedimentary Chl-a derivatives {pheophytin a + pyropheophytin a}. This offers the possibility for very high-resolution (multi)millennial-long paleoenvironmental reconstructions.

[Two cases of suspected Munchausen by proxy syndrome: the importance of forensic toxicological analyses in handling suspicions and producing evidence].

PubMed

Musshoff, Frank; Kirschbaum, Katrin M; Madea, Burkhard

2008-01-01

The authors report on two cases of suspected Munchausen by proxy syndrome. In a 3-year-old boy, clinical toxicological analyses produced suspicious clues that an antidepressant had been administered, which could not be verified by forensic toxicological investigations. In a 13-month-old boy, the mother was also suspected of having poisoned the child. Initial clinical toxicological examinations failed to explain the observed symptoms (unclear unconsciousness, narrowed pupils). While in the first case, the incorrect interpretation of findings by a laboratory without forensic experience resulted in suspicions against the mother, the cause for the observed symptoms in the second case could be proved by complex analyses not performed before and the suspicion that the clinical picture had been intentionally brought about could be cleared up (use of an antitussive containing clobutinol). The two reports show that especially in cases with a potential forensic background, adequately qualified forensic laboratories with a broad spectrum of analytical methods should be involved.

Environmental Change recorded in Lacustrine Sediments from Tangra Yumco, Tibetan Plateau, at 16.5 ka cal BP and during the Younger Dryas Chronozone

NASA Astrophysics Data System (ADS)

Henkel, K.; Ahlborn, M.; Haberzettl, T.; Kasper, T.; Daut, G.; Ju, J.; Ma, Q.; Wang, J.; Zhu, L.; Maeusbacher, R.

2013-12-01

In the purpose of understanding the recent climate change on the Tibetan Plateau (TP) and beyond and to allow predictions for future climate scenarios it is imperative to investigate past climate changes. The numerous lake systems on the TP serve as ideal archives for past hydrological changes, which are assumed to be caused by variations in strength and extent of monsoonal air masses. By now, the spatial and temporal monsoonal evolution on the TP is intensively discussed. With the focus on a W-E lake transect on the southern TP we investigate lakes with a multi-dating and multi-proxy analyses approach, which has already been successfully carried out on Nam Co, the easternmost lake of the transect. In this study, we present results from a ~11.5 m long lacustrine sediment record from the terminal lake Tangra Yumco (4,540 m a.s.l., 31°13'N, 86°43'E), representing the center of the transect. Tangra Yumco is the deepest lake recorded on the TP so far. Via a hydro-acoustic survey observed submerged beach berms (45 m below recent lake level) and exposed lake level terraces up to ~205 m above lake level indicate large lake level fluctuations in the past. The record consists of an interbedding of fine grained silty sediments with a lamination of different thicknesses (sub-mm to cm) and partly intercalated blackish sandy layers. Homogeneous areas, which occur especially in the upper two thirds of the profile, represent turbidite deposits. Until now, color- and greyscale-, magnetic susceptibility- and XRF-scanning were applied. For age control 22 14C AMS-radiocarbon measurements were carried out on bulk organic matter. To determine a possible carbon reservoir effect, additional surface sediment samples were measured as well as one modern aquatic plant. The results indicate a reservoir effect of ~2,120 +110/-90 years. Assuming a constant reservoir effect, the base of the record reveals a corrected radiocarbon age of 17,270 +325/-310 cal BP. The sediment accumulation rate is higher in the older part and changes around ~16,500 cal BP to a lower, constant one. At the same time, shifts in the Ti, K, Rb and Sr values can be observed, pointing to a hydrological change in the system. Regarding Ca and Sr values, a change in the authigenic carbonate production, reflecting a climatic change, coinciding with the timing of the Younger Dryas could be observed. This new record represents a promising archive for paleomonsoonal reconstruction on the TP with a high potential for a broad multi-proxy approach. Further analyses with different independent dating methods (i.e., U/Th, compound specific radiocarbon dating, OSL, magnetostratigraphy) as well as sedimentological (grain size, thin sections), geochemical (CNS, organic geochemistry, isotopes) and micropalaeontological (ostracods) parameters are in progress.

Resolving environmental signatures from a paleovalley sedimentary sequence from arid northwest Australia

NASA Astrophysics Data System (ADS)

Rouillard, Alexandra; Skrzypek, Grzegorz; Dogramaci, Shawan; Grierson, Pauline

2014-05-01

Sediments from paleolakes can retain invaluable archives of past environmental conditions. However, deciphering a depositional signal from digenetic processes can be challenging in arid environments owing to extremely variable rainfall and saline groundwaters, which result in aggressive chemical conditions that often limit the preservation of traditionally used proxies. We investigated the development of hydroclimatic proxies based on sediment geochemistry from the Fortescue Marsh, in the arid Pilbara region of northwest Australia. The Marsh lies in a paleovalley that acts as a terminal basin for the upper part of the Fortescue River and consists of a ~1000 km2 contiguous floodplain with freshwater pools episodically inundated during intense rainfall events. The paleovalley is bound by mountain ranges that contain some of the most Fe-ore rich and ancient deposits on Earth, which we expected to confer unique geochemical characteristics to the sediments. We used a sonic rig to retrieve a 25 m core from one of the deepest sedimentary sections of the Fortescue Marsh (86 m to bedrock). We combined δ34S and δ18O stable isotopes analyses with scanning μXRF and reflectance spectroscopy to quantitatively map the elemental and mineralogical composition of the sedimentary sequence and to identify underlying mechanisms relating to paleoclimate. We found that Fe, Ca and Sr were the most abundant elements identified by μXRF. Typically, layers of up to 1 m that were almost exclusively Fe-dominated alternated with layers of 0.3-2.4 m thickness dominated by Ca and/or Sr, with at least five intervals with distinct peaks in Sr. As expected, the hyperspectral characterization confirmed that Fe oxides were most abundant during the Fe-rich intervals. While clay minerals including kaolinite and montmorillonite were also indicated from the spectral data, this assessment is contradicted by the low relative abundance of Al and Si. Peaks in Sr don't appear to reflect carbonates nor Sr sulfates, thus further analyses are required to confirm their origin. Hyperspectral mapping and strong correlation between S and Ca confirmed that the intervals with high Ca corresponded to gypsum (CaSO4). We suggest that this gypsum is an authigenic sulfate mineral that formed within the top-most sediment due to groundwater fluctuation. Water chemistry measurements taken down the profile show that the conditions are close to saturation of gypsum throughout, and it is likely that such high concentration of crystals would form during prolonged 'dry' periods following very 'wet' periods. Under this scenario, current conditions are 'dry' but there have been significant 'wet' periods during which detrital materials, such as Fe, Rb and other low abundance metals here, have accumulated in the system via transport from the catchment. δ34S and δ18O analyses will help confirm the origins of formation of the crystals. Overall, our findings demonstrate that wetting and drying cycles and de-dolomitization processes are the main mechanisms influencing local geochemistry. Establishment of geochronology for this profile is currently underway. We are also examining other proxies including δ87Sr and particle size. Collectively, a multi-proxy and process-based approach will be used to characterize long-term hydroclimatic change in northwest Australia.

Holocene climate changes in eastern Beringia (NW North America) - A systematic review of multi-proxy evidence

NASA Astrophysics Data System (ADS)

Kaufman, Darrell S.; Axford, Yarrow L.; Henderson, Andrew C. G.; McKay, Nicholas P.; Oswald, W. Wyatt; Saenger, Casey; Anderson, R. Scott; Bailey, Hannah L.; Clegg, Benjamin; Gajewski, Konrad; Hu, Feng Sheng; Jones, Miriam C.; Massa, Charly; Routson, Cody C.; Werner, Al; Wooller, Matthew J.; Yu, Zicheng

2016-09-01

Reconstructing climates of the past relies on a variety of evidence from a large number of sites to capture the varied features of climate and the spatial heterogeneity of climate change. This review summarizes available information from diverse Holocene paleoenvironmental records across eastern Beringia (Alaska, westernmost Canada and adjacent seas), and it quantifies the primary trends of temperature- and moisture-sensitive records based in part on midges, pollen, and biogeochemical indicators (compiled in the recently published Arctic Holocene database, and updated here to v2.1). The composite time series from these proxy records are compared with new summaries of mountain-glacier and lake-level fluctuations, terrestrial water-isotope records, sea-ice and sea-surface-temperature analyses, and peatland and thaw-lake initiation frequencies to clarify multi-centennial- to millennial-scale trends in Holocene climate change. To focus the synthesis, the paleo data are used to frame specific questions that can be addressed with simulations by Earth system models to investigate the causes and dynamics of past and future climate change. This systematic review shows that, during the early Holocene (11.7-8.2 ka; 1 ka = 1000 cal yr BP), rather than a prominent thermal maximum as suggested previously, temperatures were highly variable, at times both higher and lower than present (approximate mid-20th-century average), with no clear spatial pattern. Composited pollen, midge and other proxy records average out the variability and show the overall lowest summer and mean-annual temperatures across the study region during the earliest Holocene, followed by warming over the early Holocene. The sparse data available on early Holocene glaciation show that glaciers in southern Alaska were as extensive then as they were during the late Holocene. Early Holocene lake levels were low in interior Alaska, but moisture indicators show pronounced differences across the region. The highest frequency of both peatland and thaw-lake initiation ages also occurred during the early Holocene. During the middle Holocene (8.2-4.2 ka), glaciers retreated as the regional average temperature increased to a maximum between 7 and 5 ka, as reflected in most proxy types. Following the middle Holocene thermal maximum, temperatures decreased starting between 4 and 3 ka, signaling the onset of Neoglacial cooling. Glaciers in the Brooks and Alaska Ranges advanced to their maximum Holocene extent as lakes generally rose to modern levels. Temperature differences for averaged 500-year time steps typically ranged by 1-2 °C for individual records in the Arctic Holocene database, with a transition to a cooler late Holocene that was neither abrupt nor spatially coherent. The longest and highest-resolution terrestrial water isotope records previously interpreted to represent changes in the Aleutian low-pressure system around this time are here shown to be largely contradictory. Furthermore, there are too few records with sufficient resolution to identify sub-centennial-scale climate anomalies, such as the 8.2 ka event. The review concludes by suggesting some priorities for future paleoclimate research in the region.

Holocene climate changes in eastern Beringia (NW North America) – A systematic review of multi-proxy evidence

USGS Publications Warehouse

Kaufman, Darrell S.; Axford, Yarrow L.; Henderson, Andrew C.G.; McKay, Nicolas P.; Oswald, W. Wyatt; Saenger, Casey; Anderson, R. Scott; Bailey, Hannah L.; Clegg, Benjamin; Gajewski, Konrad; Hu, Feng Sheng; Jones, Miriam C.; Massa, Charly; Routson, Cody C.; Werner, Al; Wooller, Matthew J.; Yu, Zicheng

2016-01-01

Reconstructing climates of the past relies on a variety of evidence from a large number of sites to capture the varied features of climate and the spatial heterogeneity of climate change. This review summarizes available information from diverse Holocene paleoenvironmental records across eastern Beringia (Alaska, westernmost Canada and adjacent seas), and it quantifies the primary trends of temperature- and moisture-sensitive records based in part on midges, pollen, and biogeochemical indicators (compiled in the recently published Arctic Holocene database, and updated here to v2.1). The composite time series from these proxy records are compared with new summaries of mountain-glacier and lake-level fluctuations, terrestrial water-isotope records, sea-ice and sea-surface-temperature analyses, and peatland and thaw-lake initiation frequencies to clarify multi-centennial- to millennial-scale trends in Holocene climate change. To focus the synthesis, the paleo data are used to frame specific questions that can be addressed with simulations by Earth system models to investigate the causes and dynamics of past and future climate change. This systematic review shows that, during the early Holocene (11.7–8.2 ka; 1 ka = 1000 cal yr BP), rather than a prominent thermal maximum as suggested previously, temperatures were highly variable, at times both higher and lower than present (approximate mid-20th-century average), with no clear spatial pattern. Composited pollen, midge and other proxy records average out the variability and show the overall lowest summer and mean-annual temperatures across the study region during the earliest Holocene, followed by warming over the early Holocene. The sparse data available on early Holocene glaciation show that glaciers in southern Alaska were as extensive then as they were during the late Holocene. Early Holocene lake levels were low in interior Alaska, but moisture indicators show pronounced differences across the region. The highest frequency of both peatland and thaw-lake initiation ages also occurred during the early Holocene. During the middle Holocene (8.2–4.2 ka), glaciers retreated as the regional average temperature increased to a maximum between 7 and 5 ka, as reflected in most proxy types. Following the middle Holocene thermal maximum, temperatures decreased starting between 4 and 3 ka, signaling the onset of Neoglacial cooling. Glaciers in the Brooks and Alaska Ranges advanced to their maximum Holocene extent as lakes generally rose to modern levels. Temperature differences for averaged 500-year time steps typically ranged by 1–2 °C for individual records in the Arctic Holocene database, with a transition to a cooler late Holocene that was neither abrupt nor spatially coherent. The longest and highest-resolution terrestrial water isotope records previously interpreted to represent changes in the Aleutian low-pressure system around this time are here shown to be largely contradictory. Furthermore, there are too few records with sufficient resolution to identify sub-centennial-scale climate anomalies, such as the 8.2 ka event. The review concludes by suggesting some priorities for future paleoclimate research in the region.

Andean snowpack since AD 1150 inferred from rainfall, tree-ring and documentary records

USDA-ARS?s Scientific Manuscript database

The Andean snowpack is the main source of freshwater and arguably the single most important natural resource for the populated, semi-arid regions of central Chile and central-western Argentina. However, apart from recent analyses of instrumental snowpack data, very little is known about the long ter...

Analytical report of the 2016 dengue outbreak in Córdoba city, Argentina.

PubMed

Rotela, Camilo; Lopez, Laura; Frías Céspedes, María; Barbas, Gabriela; Lighezzolo, Andrés; Porcasi, Ximena; Lanfri, Mario A; Scavuzzo, Carlos M; Gorla, David E

2017-11-06

After elimination of the Aedes aegypti vector in South America in the 1960s, dengue outbreaks started to reoccur during the 1990s; strongly in Argentina since 1998. In 2016, Córdoba City had the largest dengue outbreak in its history. In this article we report this outbreak including spatio-temporal analysis of cases and vectors in the city. A total of 653 dengue cases were recorded by the laboratory-based dengue surveillance system and georeferenced by their residential addresses. Case maps were generated from the epidemiological week 1 (beginning of January) to week 19 (mid-May). Dengue outbreak temporal evolution was analysed globally and three specific, high-incidence zones were detected using Knox analysis to characterising its spatio-temporal attributes. Field and remotely sensed data were collected and analysed in real time and a vector presence map based on the MaxEnt approach was generated to define hotspots, towards which the pesticide- based strategy was then targeted. The recorded pattern of cases evolution within the community suggests that dengue control measures should be improved.

Genetic Diversity of G3 Rotavirus Strains Circulating in Argentina during 1998–2012 Assessed by Full Genome Analyses

PubMed Central

Degiuseppe, Juan Ignacio; Parra, Gabriel Ignacio; Stupka, Juan Andrés

2014-01-01

Seasonal shifts in the predominant strains and the periodic emergence of new strains are epidemiological features of human rotaviruses. After the sporadic detection in two samples in 1998, G3P[8] strains reemerged as the predominant rotavirus during 2008–2009 in Argentina. Notably, in 2011 6.3% (37/587) of samples presented the G3P[6] genotypes, which coincided with the recent detection of G3P[6] and G2P[6] strains in South America and Europe. Analyses of the 11 gene segments of four G3P[8] and two G3P[6] strains revealed that G3P[8] strains detected a decade apart (1998 and 2009) presented minor differences, while the G3P[6] strains presented a complete different genomic constellation albeit showing a similar VP7 gene. This study provides insights in the dynamics and evolution of one of the genotypes with the wider range of hosts and inter-species transmission potential. PMID:25337915

Molecular evidence of hybrid zones of Cedrela (Meliaceae) in the Yungas of Northwestern Argentina.

PubMed

Zelener, Noga; Tosto, Daniela; de Oliveira, Luiz Orlando; Soldati, María Cristina; Inza, María Virginia; Fornes, Luis Fernando

2016-09-01

In the Yungas of Northwestern Argentina, three endangered species of Cedrela (C. angustifolia, C. saltensis, and C. balansae) follow altitudinal gradients of distribution with contact zones between them. We sampled 210 individuals from 20 populations that spanned most of Cedrela's geographical range in the Yungas, and used Amplified Fragment Length Polymorphism (AFLP) markers and DNA sequences of the nuclear Internal Transcribed Spacer (ITS) to investigate hybrid zones. Data analyses employed an array of complementary methods, including principal coordinate analyses, Bayesian clustering analyses, maximum likelihood tree-building, and network techniques. Both nuclear molecular systems - AFLP and ITS - provided insights into the evolutionary history of Cedrela in the Yungas in a congruent manner. We uncovered strong support for the occurrence of natural hybridization between C. balansae and C. saltensis. Additionally, we identified hybrid zones in areas of sympatry (at both the Calilegua National Park and the San Andrés farm) and in transition zones from 820 to 1100meters above sea level (localities of Pintascayo and Acambuco). There was no evidence for hybridization of either C. balansae or C. saltensis with C. angustifolia. The role of hybrid populations in conservation and use of genetic resources in the Yungas were discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

North Atlantic sea-level variability during the last millennium

NASA Astrophysics Data System (ADS)

Gehrels, Roland; Long, Antony; Saher, Margot; Barlow, Natasha; Blaauw, Maarten; Haigh, Ivan; Woodworth, Philip

2014-05-01

Climate modelling studies have demonstrated that spatial and temporal sea-level variability observed in North Atlantic tide-gauge records is controlled by a complex array of processes, including ice-ocean mass exchange, freshwater forcing, steric changes, changes in wind fields, and variations in the speed of the Gulf Stream. Longer records of sea-level change, also covering the pre-industrial period, are important as a 'natural' and long-term baseline against which to test model performance and to place recent and future sea-level changes and ice-sheet change into a long-term context. Such records can only be reliably and continuously reconstructed from proxy methods. Salt marshes are capable of recording decimetre-scale sea-level variations with high precision and accuracy. In this paper we present four new high-resolution proxy records of (sub-) decadal sea-level variability reconstructed from salt-marsh sediments in Iceland, Nova Scotia, Maine and Connecticut that span the past 400 to 900 years. Our records, based on more than 100 new radiocarbon analyses, Pb-210 and Cs-137 measurements as well as other biological and geochemical age markers, together with hundreds of new microfossil observations from contemporary and fossil salt marshes, capture not only the rapid 20th century sea-level rise, but also small-scale (decimetre, multi-decadal) sea-level fluctuations during preceding centuries. We show that in Iceland three periods of rapid sea-level rise are synchronous with the three largest positive shifts of the reconstructed North Atlantic Oscillation (NAO) index. Along the North American east coast we compare our data with salt-marsh records from New Jersey, North Carolina and Florida and observe a trend of increased pre-industrial sea-level variability from south to north (Florida to Nova Scotia). Mass changes and freshwater forcing cannot explain this pattern. Based on comparisons with instrumental sea-level data and modelling studies we hypothesise that multi-decadal to centennial changes in wind and air pressure are more important than mass flux from land-based ice as drivers of North Atlantic sea-level variability during the last millennium.

Vegetation history and paleoclimate at Lake Dojran (FYROM/Greece) during the Late Glacial and Holocene

NASA Astrophysics Data System (ADS)

Masi, Alessia; Francke, Alexander; Pepe, Caterina; Thienemann, Matthias; Wagner, Bernd; Sadori, Laura

2018-03-01

A new high-resolution pollen and NPP (non-pollen palynomorph) analysis has been performed on the sediments of Lake Dojran, a transboundary lake located at the border between Greece and the former Yugoslav Republic of Macedonia (FYROM). The sequence covers the last 12 500 years and provides information on the vegetational dynamics of the Late Glacial and Holocene for the southern Balkans. Robust age model, sedimentological diatom, and biomarker analyses published previously have been the base for a multi-perspective interpretation of the new palynological data. Pollen analysis revealed that the Late Glacial is characterized by steppic taxa with prevailing Amaranthaceae, Artemisia and Poaceae. The arboreal vegetation starts to rise after 11 500 yr BP, taking a couple of millennia to be definitively attested. Holocene vegetation is characterized by the dominance of mesophilous plants. The Quercus robur type and Pinus are the most abundant taxa, followed by the Quercus cerris type, the Quercus ilex type and Ostrya-Carpinus orientalis. The first attestation of human presence can be presumed at 5000 yr BP from the contemporary presence of cereals, Juglans and Rumex. A drop in both pollen concentration and influx together with a δ18Ocarb shift indicates increasing aridity and precedes clear and continuous human signs since 4000 yr BP. Also, a correlation between Pediastrum boryanum and fecal stanol suggests that the increase in nutrients in the water is related to human presence and pasture. An undoubted expansion of human-related plants occurs since 2600 yr BP when cereals, arboreal cultivated and other synanthropic non-cultivated taxa are found. A strong reduction in arboreal vegetation occurred at 2000 yr BP, when the Roman Empire impacted a landscape undergoing climate dryness in the whole Mediterranean area. In recent centuries the human impact still remains high but spots of natural vegetation are preserved. The Lake Dojran multi-proxy analysis including pollen data provides clear evidence of the importance of this approach in paleoenvironmental reconstruction. Cross-interpretation of several proxies allows us to comprehend past vegetation dynamics and human impact in the southern Balkans.

Mid- to late Holocene climate-driven regime shifts inferred from diatom, ostracod and stable isotope records from Lake Son Kol (Central Tian Shan, Kyrgyzstan)

NASA Astrophysics Data System (ADS)

Schwarz, Anja; Turner, Falko; Lauterbach, Stefan; Plessen, Birgit; Krahn, Kim J.; Glodniok, Sven; Mischke, Steffen; Stebich, Martina; Witt, Roman; Mingram, Jens; Schwalb, Antje

2017-12-01

Arid Central Asia represents a key region for understanding climate variability and interactions in the Northern Hemisphere. Patterns and mechanisms of Holocene climate change in arid Central Asia are, however, only partially understood. Multi-proxy data combining diatom, ostracod, sedimentological, geochemical and stable isotope analyses from a ca. 6000-year-old lake sediment core from Son Kol (Central Kyrgyzstan) show distinct and repeated changes in species assemblages. Diatom- and ostracod-inferred conductivity shifts between meso-euhaline and freshwater conditions suggest water balance and regime shifts. Organism-derived data are corroborated by stable isotope, mineralogical and geochemical records, underlining that Son Kol was affected by strong lake level fluctuations of several meters. The δ13Ccarb/δ18Ocarb correlation shows repeated switchovers from a closed to an open lake system. From 6000 to 3800 and 3250 to 1950 cal. yr BP, Son Kol was a closed basin lake with higher conductivities, increased nutrient availability and a water level located below the modern outflow. Son Kol became again a hydrologically open lake at 3800 and 1950 cal. yr BP. Comparisons to other local and regional paleoclimate records indicate that these regime shifts were largely controlled by changing intensity and position of the Westerlies and the Siberian Anticyclone that triggered changes in the amount of winter precipitation. A strong influence of the Westerlies ca. 5000-4400, 3800-3250 and since 1950 cal. yr BP enhanced the amount of precipitation during spring, autumn and winter, whereas cold and dry winters prevailed during phases with a strong Siberian Anticyclone and southward shifted Westerlies at ca. 6000-5000, 4400-3800 and 3250-1950 cal. yr BP. Similarities between variations in winter precipitation at Son Kol and records of the predominant NAO-mode further suggest a teleconnection between wet (dry) winter climate in Central Asia and a positive (negative) NAO-mode. Thus, this study identifies climate fluctuations as the main driver for hydrological regime shifts in Son Kol controlling physicochemical conditions and consequently causing abrupt species assemblage changes. This emphasizes the importance of multi-proxy approaches to identify triggers, thresholds and cascades of aquatic ecosystem transformations.

78 FR 46325 - Pacific Fishery Management Council (Pacific Council); Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-31

... Groundfish Subcommittee teleconference is to discuss analytical approaches for a meta-analysis of... development of analyses used to inform proxy F MSY harvest rates for consideration by the Pacific Council's...

The validity of proxy-based data on loneliness in suicide research: a case-control psychological autopsy study in rural China.

PubMed

Niu, Lu; Jia, Cunxian; Ma, Zhenyu; Wang, Guojun; Yu, Zhenjun; Zhou, Liang

2018-05-01

There is a lack of evidence for the role of loneliness on suicide using psychological autopsy method, and the validity of proxy informants' reports on loneliness is not well established. This study aimed to investigate the validity of proxy respondent reports on loneliness, and the reliability and validity of the University of California Los Angeles Loneliness Scale-6 (ULS-6) as used in psychological autopsy method with rural elderly people in China. Two hundred forty-two suicide cases and 242 normal community controls were selected, and the psychological autopsy method was utilized to collect information. Data from proxy respondents of the living controls were compared with data reported by the targets (gold standards). Subject-proxy concordance for ULS-6 was fair (ICC = 0.447) in the living controls. The suicide cases were more likely to have a higher score of ULS-6 than the living controls. Additionally, our data supported that ULS-6 had adequate psychometric properties in both suicide and control groups: factor analyses yielded one-factor component solution; Cronbach's alpha (both > 0.90) demonstrated excellent internal consistency; the Spearman correlation analysis indicated that the ULS-6 score was positively correlated with depression; and negatively correlated with QOL and social support. Results support proxy-based data on loneliness in research of suicide in older adults in rural China, and the ULS-6 is a psychometrically sound instrument for measuring loneliness in psychological autopsy studies.

An extended network of documentary data from South America and its potential for quantitative precipitation reconstructions back to the 16th century

NASA Astrophysics Data System (ADS)

Neukom, Raphael; del Rosario Prieto, María; Moyano, Rodolfo; Luterbacher, Jürg; Pfister, Christian; Villalba, Ricardo; Jones, Philip D.; Wanner, Heinz

2009-06-01

In South America (SA) several documentary based climate time series exist, some of them extending back to the 16th century. Most of these records end in the 19th century, and can not be calibrated against instrumental data. Here, we used the newspaper “Los Andes” from Mendoza, Argentina, to extend documentary based indices of Mendoza precipitation and Central Andes snow depth to the late 20th century. A statistical approach to create “pseudo documentary” 20th century data was applied to prolong eight other documentary records. Increased variability of the hydrological cycle in the Central Andes and prevailing periods of wet and dry years in Mendoza suggest that the 20th century is extraordinary in the context of the last 400 years. The final set of extended documentaries explains significant portions of SA precipitation variability in large areas between 20°S and 40°S and can therefore improve the network of annually resolved precipitation proxies.

A Plant-Based Proxy for the Oxygen Isotope Ratio of Atmospheric Water Vapor

NASA Astrophysics Data System (ADS)

Helliker, B.

2007-12-01

Atmospheric water vapor is a major component of the global hydrological cycle, but the isotopic balance of vapor is largely unknown. It is shown here that the oxygen isotope ratio of leaf water in the epiphytic Crassulacean acid metabolism (CAM) plant Tillandsia usneoides (Spanish Moss) is controlled by the oxygen isotope ratio of atmospheric water vapor in both field and lab studies. Assuming that the leaf-water isotopic signature (and hence the atmospheric water vapor signature) is recorded in plant organic material, the atmospheric water vapor oxygen isotope ratios for Miami, Florida (USA) were reconstructed for several years from 1878 to 2005 using contemporary and herbarium specimens. T. usneoides ranges from Virginia, USA southwards through the tropics to Argentina, and the CAM epiphytic lifeform is widespread in other species. Therefore, epiphytes may be used to reconstruct the isotope ratio of atmospheric water for spatial scales that span over 60° of latitude and temporal scales that cover the last century of global temperature increase.

Early meteorological records from Latin-America and the Caribbean during the 18th and 19th centuries

PubMed Central

Domínguez-Castro, Fernando; Vaquero, José Manuel; Gallego, María Cruz; Farrona, Ana María Marín; Antuña-Marrero, Juan Carlos; Cevallos, Erika Elizabeth; Herrera, Ricardo García; de la Guía, Cristina; Mejía, Raúl David; Naranjo, José Manuel; del Rosario Prieto, María; Ramos Guadalupe, Luis Enrique; Seiner, Lizardo; Trigo, Ricardo Machado; Villacís, Marcos

2017-01-01

This paper provides early instrumental data recovered for 20 countries of Latin-America and the Caribbean (Argentina, Bahamas, Belize, Brazil, British Guiana, Chile, Colombia, Costa Rica, Cuba, Ecuador, France (Martinique and Guadalupe), Guatemala, Jamaica, Mexico, Nicaragua, Panama, Peru, Puerto Rico, El Salvador and Suriname) during the 18th and 19th centuries. The main meteorological variables retrieved were air temperature, atmospheric pressure, and precipitation, but other variables, such as humidity, wind direction, and state of the sky were retrieved when possible. In total, more than 300,000 early instrumental data were rescued (96% with daily resolution). Especial effort was made to document all the available metadata in order to allow further post-processing. The compilation is far from being exhaustive, but the dataset will contribute to a better understanding of climate variability in the region, and to enlarging the period of overlap between instrumental data and natural/documentary proxies. PMID:29135974

Glacial-Interglacial, Orbital and Millennial-Scale Climate Variability for the Last Glacial Cycle at Shackleton Site U1385 based on Dinoflagellate Cysts

NASA Astrophysics Data System (ADS)

Datema, M.

2015-12-01

The Shackleton Site (IODP Expedition 339 Site U1385), located off the West-Portuguese Margin, preserves a continuous high-fidelity record of millennial-scale climate variability for the last several glacial cycles (~1.4 Myr) that can be correlated precisely to patterns observed in polar ice cores. In addition, rapid delivery of terrestrial material to the deep-sea environment allows the correlation of these marine records to European terrestrial climate records. This unique marine-ice-terrestrial linkage makes the Shackleton Site the ideal reference section for studying Quaternary abrupt climate change. The main objective of studying Site U1385 is to establish a marine reference section of Pleistocene climate change. We generated (sub)millennial-scale (~600 year interval) dinoflagellate cyst (dinocyst) assemblage records from Shackleton Site U1385 (IODP Expedition 339) to reconstruct sea surface temperature (SST) and productivity/upwelling over the last 152 kyrs. In addition, our approach allows for detailed land-sea correlations, because we also counted assemblages of pollen and spores from higher plants. Dinocyst SST and upwelling proxies, as well as warm/cold pollen proxies from Site U1385 show glacial-interglacial, orbital and stadial-interstadial climate variability and correlate very well to Uk'37, planktic foraminifer δ18O and Ca/Ti proxies of previously drilled Shackleton Sites and Greenland Ice Core δ18O. The palynological proxies capture (almost) all Dansgaard-Oeschger events of the last glacial cycle, also before ~70 ka, where millennial-scale variability is overprinted by precession. We compare the performance and results of the palynology of Site U1385 to proxies of previously drilled Shackleton Sites and conclude that palynology strengthens the potential of this site to form a multi-proxy reference section for millennial scale climate variability across the Pleistocene-Holocene. Finally, we will present a long-term paleoceanographic perspective down to ~150 ka.

Multicentury Reconstruction of Precipitations (1300-2014) in Eastern Canada from Tree-Ring Width and Carbon and Oxygen Isotopes

NASA Astrophysics Data System (ADS)

Giguère, Claudie; Boucher, Étienne; Bergeron, Yves

2016-04-01

Tree ring series enabling long hydroclimatic reconstructions are scarce in Northeastern America, mostly because most boreal species are rather thermo-dependant. Here we propose a new multi-proxy analysis (tree-ring, δ13C and δ18O) from one of the oldest Thuja occidentalis population in NE America (lake Duparquet, Quebec). These rare precipitation-sensitive, long-living trees (> 800 years) grow on xeric rocky shores and their potential for paleo-hydroclimatic reconstructions (based on ring widths solely) was previously assessed. The objectives of this study are twofold i) to strengthen the hydroclimatic signal of this long tree-ring chronology by adding analysis of stable isotope ratios (δ13C and δ18O) and ii) to reconstruct summer precipitation back to 1300 AD, which will represent, by far, the longest high-resolution hydroclimatic reconstruction in this region. A tree-ring chronology was constructed from 61 trees sampled in standing position. Eleven trees were also sampled to produce pooled carbon and oxygen isotope chronologies (annually resolved) with a replication of five to six trees per year. Signal analysis (correlation between climatic data and proxy values) confirms that growth is positively influenced by spring precipitations (May-June), while δ13C is negatively correlated to summer precipitation (June to August) and positively to June temperature. Adding δ18O analysis will strengthen the signal even more, since wood cellulose should be enriched in δ18O when high evapotranspiration conditions prevail. Based on a multi-proxy approach, a summer precipitation reconstruction was developed and compared to other temperature reconstructions from this region as well as to southernmost hydroclimatic reconstructions (e.g. Cook et al). A preliminary analysis of external and internal forcing is proposed in conclusion.

Centennial-scale winter climate variability over the last two millennia in the northern Gulf of Mexico based on paired δ18O and Mg/Ca in Globorotalia truncatulinoides

NASA Astrophysics Data System (ADS)

Fortiz, V.; Thirumalai, K.; Richey, J. N.; Quinn, T. M.

2014-12-01

We present a replicated record of paired foraminiferal δ18O and Mg/Ca variations in multi-cores collected from the Garrison Basin (26º43'N, 93º55'W) in the northern Gulf of Mexico (GOM). Using δ18O (sea surface temperature, SST; sea surface salinity, SSS proxy) and Mg/Ca (SST proxy) variations in non-encrusted planktic foraminifer Globorotalia truncatulinoides we produce time series spanning the last two millennia that is characterized by centennial-scale climate variability. We interpret geochemical variations in G. truncatulinoides to reflect winter climate variability because data from a sediment trap, located ~350 km east of the core site, reveal that annual flux of G. truncatulinoides is heavily weighted towards winter (peak production in January-February; Spear et al., 2011). Similar centennial-scale variability is also observed in the foraminiferal geochemistry of Globigerinoides ruber in the same multi-cores, which likely reflect mean annual climate variations. Our replicated results and comparisons to other SST reconstructions from the region lend confidence that the northern GOM surface ocean underwent large, centennial-scale variability, most likely dominated by changes in winter climate. This variability occurred in a time period where climate forcing is small and background conditions are similar to pre-industrial times. References: Spear, J.W.; Poore, R.Z., and Quinn, T.M., 2011, Globorotalia truncatulinoides (dextral) Mg/Ca as a proxy for Gulf of Mexico winter mixed-layer temperature: Evidence from a sediment trap in the northern Gulf of Mexico. Marine Micropaleontology, 80, 53-61.

José Bleger: Jew, Marxist and psychoanalyst.

PubMed

Plotkin, Mariano

2011-01-01

The article analyses the trajectory of Dr. José Bleger (1922-1972), an Argentine psychoanalyst who tried to articulate his triple identity as a Jew, a Marxist, and a psychoanalyst. Bleger played a central role in the constitution of the 'psy movement' and, in more general terms, in the diffusion of a 'psy culture' in Argentina, a country that today is considered as one of the 'world capitals of psychoanalysis'. However, his trajectory showed not only the limits of his projects in the increasingly politically polarized Argentina of the 1960s, as well as their internal contradictions, but also the difficulties of articulating different identities in those agitated times. Through an analysis of Bleger's trajectory this article explores larger issues of Argentine political culture and their relations with the emergence of a psychoanalytic culture.

Sao Paulo Lightning Mapping Array (SP-LMA): Network Assessment and Analyses for Intercomparison Studies and GOES-R Proxy Activities

NASA Technical Reports Server (NTRS)

Bailey, J. C.; Blakeslee, R. J.; Carey, L. D.; Goodman, S. J.; Rudlosky, S. D.; Albrecht, R.; Morales, C. A.; Anselmo, E. M.; Neves, J. R.; Buechler, D. E.

2014-01-01

A 12 station Lightning Mapping Array (LMA) network was deployed during October 2011 in the vicinity of Sao Paulo, Brazil (SP-LMA) to contribute total lightning measurements to an international field campaign [CHUVA - Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)]. The SP-LMA was operational from November 2011 through March 2012 during the Vale do Paraiba campaign. Sensor spacing was on the order of 15-30 km, with a network diameter on the order of 40-50km. The SP-LMA provides good 3-D lightning mapping out to 150 km from the network center, with 2-D coverage considerably farther. In addition to supporting CHUVA science/mission objectives, the SP-LMA is supporting the generation of unique proxy data for the Geostationary Lightning Mapper (GLM) and Advanced Baseline Imager (ABI), on NOAA's Geostationary Operational Environmental Satellite-R (GOES-R: scheduled for a 2015 launch). These proxy data will be used to develop and validate operational algorithms so that they will be ready to use on "day1" following the GOES-R launch. As the CHUVA Vale do Paraiba campaign opportunity was formulated, a broad community-based interest developed for a comprehensive Lightning Location System (LLS) intercomparison and assessment study, leading to the participation and/or deployment of eight other ground-based networks and the space-based Lightning Imaging Sensor (LIS). The SP-LMA data is being intercompared with lightning observations from other deployed lightning networks to advance our understanding of the capabilities/contributions of each of these networks toward GLM proxy and validation activities. This paper addresses the network assessment including noise reduction criteria, detection efficiency estimates, and statistical and climatological (both temporal and spatially) analyses for intercomparison studies and GOES-R proxy activities.

Relationship between physical performance and self-reported function in healthy individuals across the lifespan.

PubMed

Baldwin, Jennifer N; McKay, Marnee J; Hiller, Claire E; Moloney, Niamh; Nightingale, Elizabeth J; Burns, Joshua

2017-08-01

Functional outcome measures in clinical trials of musculoskeletal conditions need to be meaningful to individuals. To investigate the relationship between physical performance and self/proxy-reported function in 1000 healthy children and adults. Cross-sectional observational study (1000 Norms Project). One thousand males and females aged 3-101 years, healthy by self-report and without major physical disability, were recruited. Twelve performance-based tests were analysed: vertical and long jump, two hand dexterity tests, four balance tests, stepping reaction time, 30-second chair stand, timed up-and-down stairs, and six-minute walk. Self/proxy-reported function was assessed using the Infant-Toddler Quality of Life questionnaire, Child Health Questionnaire, Assessment of Quality of Life (AQoL)-6D Adolescent, AQoL-8D, International Physical Activity Questionnaire and work ability question. Bivariate and multivariate correlational analyses were constructed for infants (3-4y), children (5-10y), adolescents (11-17y), adults (18-59y) and older adults (60+). Socio-demographic characteristics were similar to the Australian population. Among infants/children, greater jump and sit-to-stand performance correlated with higher proxy-reported function (p < 0.05). There were no significant relationships observed for adolescents (p > 0.05). Greater jump, dexterity, balance, reaction time, sit-to-stand, stair-climbing and six-minute walk performance correlated with higher self-reported function in adults (r = -0.097 to.231; p < 0.05) and older adults (r = -0.135 to 0.625; p < 0.05). Multivariate regression modelling revealed a collection of independent performance measures explaining up to 46% of the variance in self/proxy-reported function. Many performance-based tests were significantly associated with self/proxy-reported function. We have identified a set of physical measures which could form the basis of age-appropriate functional scales for clinical trials of musculoskeletal conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Atlantic forcing of Western Mediterranean winter rain minima during the last 12,000 years

NASA Astrophysics Data System (ADS)

Zielhofer, Christoph; Fletcher, William J.; Mischke, Steffen; De Batist, Marc; Campbell, Jennifer F. E.; Joannin, Sebastien; Tjallingii, Rik; El Hamouti, Najib; Junginger, Annett; Stele, Andreas; Bussmann, Jens; Schneider, Birgit; Lauer, Tobias; Spitzer, Katrin; Strupler, Michael; Brachert, Thomas; Mikdad, Abdeslam

2017-02-01

The limited availability of high-resolution continuous archives, insufficient chronological control, and complex hydro-climatic forcing mechanisms lead to many uncertainties in palaeo-hydrological reconstructions for the Western Mediterranean. In this study we present a newly recovered 19.63 m long core from Lake Sidi Ali in the North African Middle Atlas, a transition zone of Atlantic, Western Mediterranean and Saharan air mass trajectories. With a multi-proxy approach based on magnetic susceptibility, carbonate and total organic C content, core-scanning and quantitative XRF, stable isotopes of ostracod shells, charcoal counts, Cedrus pollen abundance, and a first set of diatom data, we reconstruct Western Mediterranean hydro-climatic variability, seasonality and forcing mechanisms during the last 12,000 yr. A robust chronological model based on AMS 14C dated pollen concentrates supports our high-resolution multi-proxy study. Long-term trends reveal low lake levels at the end of the Younger Dryas, during the mid-Holocene interval 6.6 to 5.4 cal ka BP, and during the last 3000 years. In contrast, lake levels are mostly high during the Early and Mid-Holocene. The record also shows sub-millennial- to centennial-scale decreases in Western Mediterranean winter rain at 11.4, 10.3, 9.2, 8.2, 7.2, 6.6, 6.0, 5.4, 5.0, 4.4, 3.5, 2.9, 2.2, 1.9, 1.7, 1.5, 1.0, 0.7, and 0.2 cal ka BP. Early Holocene winter rain minima are in phase with cooling events and millennial-scale meltwater discharges in the sub-polar North Atlantic. Our proxy parameters do not show so far a clear impact of Saharan air masses on Mediterranean hydro-climate in North Africa. However, a significant hydro-climatic shift at the end of the African Humid Period (∼5 ka) indicates a change in climate forcing mechanisms. The Late Holocene climate variability in the Middle Atlas features a multi-centennial-scale NAO-type pattern, with Atlantic cooling and Western Mediterranean winter rain maxima generally associated with solar minima.

Teleconnection stationarity, variability and trends of the Southern Annular Mode (SAM) during the last millennium

NASA Astrophysics Data System (ADS)

Dätwyler, Christoph; Neukom, Raphael; Abram, Nerilie J.; Gallant, Ailie J. E.; Grosjean, Martin; Jacques-Coper, Martín; Karoly, David J.; Villalba, Ricardo

2017-11-01

The Southern Annular Mode (SAM) is the leading mode of atmospheric interannual variability in the Southern Hemisphere (SH) extra-tropics. Here, we assess the stationarity of SAM spatial correlations with instrumental and paleoclimate proxy data for the past millennium. The instrumental period shows that temporal non-stationarities in SAM teleconnections are not consistent across the SH land areas. This suggests that the influence of the SAM index is modulated by regional effects. However, within key-regions with good proxy data coverage (South America, Tasmania, New Zealand), teleconnections are mostly stationary over the instrumental period. Using different stationarity criteria for proxy record selection, we provide new austral summer and annual mean SAM index reconstructions over the last millennium. Our summer SAM reconstructions are very robust to changes in proxy record selection and the selection of the calibration period, particularly on the multi-decadal timescale. In contrast, the weaker performance and lower agreement in the annual mean SAM reconstructions point towards changing teleconnection patterns that may be particularly important outside the summer months. Our results clearly portend that the temporal stationarity of the proxy-climate relationships should be taken into account in the design of comprehensive regional and hemispherical climate reconstructions. The summer SAM reconstructions show no significant relationship to solar, greenhouse gas and volcanic forcing, with the exception of an extremely strong negative anomaly following the AD 1257 Samalas eruption. Furthermore, reconstructed pre-industrial summer SAM trends are very similar to trends obtained by model control simulations. We find that recent trends in the summer SAM lie outside the 5-95% range of pre-industrial natural variability.

Hydroclimate variability in Scandinavia over the last millennium - insights from a climate model-proxy data comparison

NASA Astrophysics Data System (ADS)

Seftigen, Kristina; Goosse, Hugues; Klein, Francois; Chen, Deliang

2017-12-01

The integration of climate proxy information with general circulation model (GCM) results offers considerable potential for deriving greater understanding of the mechanisms underlying climate variability, as well as unique opportunities for out-of-sample evaluations of model performance. In this study, we combine insights from a new tree-ring hydroclimate reconstruction from Scandinavia with projections from a suite of forced transient simulations of the last millennium and historical intervals from the CMIP5 and PMIP3 archives. Model simulations and proxy reconstruction data are found to broadly agree on the modes of atmospheric variability that produce droughts-pluvials in the region. Despite these dynamical similarities, large differences between simulated and reconstructed hydroclimate time series remain. We find that the GCM-simulated multi-decadal and/or longer hydroclimate variability is systematically smaller than the proxy-based estimates, whereas the dominance of GCM-simulated high-frequency components of variability is not reflected in the proxy record. Furthermore, the paleoclimate evidence indicates in-phase coherencies between regional hydroclimate and temperature on decadal timescales, i.e., sustained wet periods have often been concurrent with warm periods and vice versa. The CMIP5-PMIP3 archive suggests, however, out-of-phase coherencies between the two variables in the last millennium. The lack of adequate understanding of mechanisms linking temperature and moisture supply on longer timescales has serious implications for attribution and prediction of regional hydroclimate changes. Our findings stress the need for further paleoclimate data-model intercomparison efforts to expand our understanding of the dynamics of hydroclimate variability and change, to enhance our ability to evaluate climate models, and to provide a more comprehensive view of future drought and pluvial risks.

Marine sedimentary coring and high-quality, multi-proxy records in the high-latitude North Pacific: a synthesis of paleoceanographic cruise and research effort

NASA Astrophysics Data System (ADS)

Borreggine, M. J.; Myhre, S. E.; Smith-Mislan, A.; Davis, C. V.; Deutsch, C.

2016-12-01

We assessed sedimentary coring efforts, data acquisition and publications from the subpolar North Pacific and marginal seas from 1951-2015. We found a total of 1,249 sediment cores collected by American, French, Japanese and Russian research vessels across the Subarctic Pacific (639 cores), Alaskan Gyre (8 cores), Sea of Okhotsk (270 cores), Bering Sea (120 cores), and the Sea of Japan (212 cores). Of these, 27% are investigated in peer-reviewed publications; this fraction varies from the Subarctic Pacific (18%), Alaskan Gyre (100%), Sea of Okhotsk (33%), Bering Sea (57%), and the Sea of Japan (25%). We assess the biological, geochemical, isotopic, and stratigraphic lines of evidence available for these cores, alongside coring technology, location, depth, cruise and vessel metadata. Coring effort peaked in 1996, 2009, and 2010 where 86, 90, and 67 cores, respectively, were recovered in the five regions collectively. Piston cores are the most common (347 cores) of the 24 different coring technologies used in the last 64 years. Published sedimentation rates range across the Subarctic Pacific (0.132-208 cm/ka), Alaskan Gyre (9-10,000 cm/ka), Sea of Okhotsk (0.7-115.5 cm/ka), Bering Sea (3-250 cm/ka), and the Sea of Japan (0.5-25 cm/ka), with the highest rates in the Alaskan Gyre. Age model development has transitioned from singular techniques to multiproxy approaches. Recent chronologies are built using a mix of isotope stratigraphy, radiocarbon dating, magnetostratigraphy, biostratigraphy, tephrochronology, % opal, color, and lithophysical proxies. Out of 275 published chronologies for the North Pacific, 132 (48%) are built with radiocarbon dating. Sedimentary data in the North Pacific includes biological, geochemical, isotopic, and stratigraphic analyses, and we document all proxy evidence to-date across all cores assessed. This database of coring and publication provides a unique resource and comprehensive assessment to the paleoceanographic community, can be used to identify strengths and weaknesses in North Pacific paleoceanography, and will be made publicly available. Additionally, the database is used to recreate past sea ice, temperature, and oxygen conditions in two additional submissions at the 2016 AGU Fall Meeting.

Reconstructing lake evaporation history and the isotopic composition of precipitation by a coupled δ18O-δ2H biomarker approach

NASA Astrophysics Data System (ADS)

Hepp, Johannes; Tuthorn, Mario; Zech, Roland; Mügler, Ines; Schlütz, Frank; Zech, Wolfgang; Zech, Michael

2015-10-01

Over the past decades, δ18O and δ2H analyses of lacustrine sediments became an invaluable tool in paleohydrology and paleolimnology for reconstructing the isotopic composition of past lake water and precipitation. However, based on δ18O or δ2H records alone, it can be challenging to distinguish between changes of the precipitation signal and changes caused by evaporation. Here we propose a coupled δ18O-δ2H biomarker approach that provides the possibility to disentangle between these two factors. The isotopic composition of long chain n-alkanes (n-C25, n-C27, n-C29, n-C31) were analyzed in order to establish a 16 ka Late Glacial and Holocene δ2H record for the sediment archive of Lake Panch Pokhari in High Himalaya, Nepal. The δ2Hn-alkane record generally corroborates a previously established δ18Osugar record reporting on high values characterizing the deglaciation and the Older and the Younger Dryas, and low values characterizing the Bølling and the Allerød periods. Since the investigated n-alkane and sugar biomarkers are considered to be primarily of aquatic origin, they were used to reconstruct the isotopic composition of lake water. The reconstructed deuterium excess of lake water ranges from +57‰ to -85‰ and is shown to serve as proxy for the evaporation history of Lake Panch Pokhari. Lake desiccation during the deglaciation, the Older Dryas and the Younger Dryas is affirmed by a multi-proxy approach using the Hydrogen Index (HI) and the carbon to nitrogen ratio (C/N) as additional proxies for lake sediment organic matter mineralization. Furthermore, the coupled δ18O and δ2H approach allows disentangling the lake water isotopic enrichment from variations of the isotopic composition of precipitation. The reconstructed 16 ka δ18Oprecipitation record of Lake Panch Pokhari is well in agreement with the δ18O records of Chinese speleothems and presumably reflects the Indian Summer Monsoon variability.

Increasing diversity of land planarians (Platyhelminthes: Geoplanidae) in the Interior Atlantic Forest with the description of two new species and new records from Argentina.

PubMed

Negrete, Lisandro; Brusa, Francisco

2017-12-04

Here, we describe two new species of land planarians of the genera Pasipha and Imbira from the Atlantic Forest of Argentina: Pasipha quirogai sp. nov. and Imbira negrita sp. nov. Their external features and internal anatomy distinguish them from their congeners. Pasipha quirogai sp. nov. is about 40mm long, characterized by brown beige dorsal pigmentation with a golden yellow median band and thin graphite black para-median stripes, cylindrical pharynx, extrabulbar prostatic vesicle with paired proximal portion, male atrium with small folds in its proximal part, and female canal opening into the dorso-caudal wall of the female atrium. Imbira negrita sp. nov. is about 110mm long, with jet black dorsal pigmentation, pharynx collar-type, short female canal opening in the postero-dorsal portion of the female atrium, and epithelial lining of female atrium with stratified appearance. We also provide exhaustive descriptions of Geoplana quagga, Obama ladislavii, and Paraba multicolor, all recorded for the first time in Argentina, by analysing anatomical features of taxonomic relevance. In addition, we improve the description of G. quagga, mainly regarding the musculature, secretory cells, and the copulatory apparatus.

Was the Little Ice Age more or less El Niño-like than the Mediaeval Climate Anomaly? Evidence from hydrological and temperature proxy data

NASA Astrophysics Data System (ADS)

Henke, L. M. K.; Lambert, F. H.; Charman, D. J.

2015-11-01

The El Niño-Southern Oscillation (ENSO), an ocean-atmosphere coupled oscillation over the equatorial Pacific, is the most important source of global climate variability on inter-annual time scales. It has substantial environmental and socio-economic consequences such as devastation of South American fish populations and increased forest fires in Indonesia. The instrumental ENSO record is too short for analysing long-term trends and variability, hence proxy data is used to extend the record. However, different proxy sources have produced varying reconstructions of ENSO, with some evidence for a temperature-precipitation divergence in ENSO trends over the past millennium, in particular during the Mediaeval Climate Anomaly (MCA; AD 800-1300) and the Little Ice Age (LIA; AD 1400-1850). This throws into question the stability of the modern ENSO system and its links to the global climate, which has implications for future projections. Here we use a new statistical approach using EOF-based weighting to create two new large-scale ENSO reconstructions derived independently from precipitation proxies and temperature proxies respectively. The method is developed and validated using pseudoproxy experiments that address the effects of proxy dating error, resolution and noise to improve uncertainty estimations. The precipitation ENSO reconstruction displays a significantly more El Niño-like state during the LIA than the MCA, while the temperature reconstruction shows no significant difference. The trends shown in the precipitation ENSO reconstruction are relatively robust to variations in the precipitation EOF pattern. However, the temperature reconstruction suffers significantly from a lack of high-quality, favourably located proxy records, which limits its ability to capture the large-scale ENSO signal. Further expansion of the palaeo-database and improvements to instrumental, satellite and model representations of ENSO are needed to fully resolve the discrepancies found among proxy records.

Multi-method investigation of cushion peatlands (

NASA Astrophysics Data System (ADS)

Forbriger, M.; Schittek, K.; Höfle, B.; Siart, C.; Eitel, B.

2012-04-01

This study presents a multi-method and multi-proxy approach for palaeonvironmental investigations in the western andean cordillera of southern Peru (Lucanas province, 14° S) using cushion peatlands as terrestrial geoarchives. The region stretching between the Altiplano and the Peruvian desert in the lowland shares a long term settlement history, in which local cultures adapted to climate change in many different ways. Being one of the most outstanding human remains, the abri below Cerro Llamoca, 4.450 m a.s.l. in the uppermost ranges of the Llamoca peatland catchment area further reveals an occupation history of almost 10.000 years, as revealed by latest archaeological investigations. In remote and highly elevated regions such as the central Andes, cushion peatlands basically represent the only high resolution terrestrial archives suitable for geoarchaeological and palaeoenvironmental studies. Characterized by high accumulation rates, they ideally document environmental changes, particularly at small time intervals. Within the multidisciplinary project 'Andean Transect - Climate Sensitivity of pre-Columbian Man-Environment-Systems' several sediment cores with depths up to 11.5 m b.s. were recovered from the Llamoca peatland. Based on almost 100 AMS 14C-datings they provide a chronology of 8000 years and, thus, offer profound insights into climatic and environmental changes in the study area. While nearly homogeneous peat layers record stable environmental conditions, the heterogeneous granulometric composition of intercalated sediment layers documents several periods of intense geomorphodynamic activity. Due to high resolution geochemical analyses of peat layers (1 cm interval; humification degree, CNS measurements, XRF-scanning), the existence of slight and short-term trends of landscape development during these phases can be identified. Additional pollen, charred particles and plant macrofossil analyses confirm these findings and help reconstructing local vegetation history. High-resolution digital elevation models derived from terrestrial laser scanning (TLS) provide important input data for geomorphologic analyses on current geomorphic processes that can be transferred to former times. Detailed subsurface information obtained by geophysics (electrical resistivity tomography ERT) helped identify the most suitable sampling sites. Information about peat thickness, stratigraphy and depth to bedrock was combined with topographical elevation data, chronometrical outcomes and palaeoenvironmental parameters to generate subsurface models of the study site. The findings allow reconstructing and visualizing the ancient landscape and the stages of peat development, which coincide with pre-Columbian cultural eras.

Climate at the edge of human dispersal in the European Middle Pleistocene

NASA Astrophysics Data System (ADS)

Horne, David

2014-05-01

Pleistocene palaeoclimatic reconstructions based on fossils from sites containing archaeological evidence of human occupation can answer key questions about the climatic context of early human dispersal in Europe. Biological proxies including foraminifera, ostracods, diatoms, chironomid larvae, molluscs and pollen are widely used to estimate palaeoclimatic parameters, typically palaeotemperatures, using indicator species, Mutual Climatic Range (MCR), Modern Analogue Technique (MAT) and transfer function approaches. Any single proxy method will yield plausible results, but there is a need for multi-proxy testing; matching or overlapping results inspire confidence, whereas if independent proxies yield results that do not match or even overlap, one or more must be wrong. The Multi-Proxy Consensus (MPC) approach not only compares two or more proxy results in order to check for agreement, but also offers potential for more refined results to be obtained from the range of mutual agreement between two or more overlapping palaeotemperature ranges. Studies of MIS9 (late Middle Pleistocene) deposits in the Thames-Medway river system in SE England (some of which contain stone implements representing human occupation) have yielded palaeotemperature estimates based on ostracods, beetles, fish, herpetiles, pollen and plant macrofossils. The MPC approach demonstrates the consistency of the results and defines a more continental climate than today (mean July air temperatures similar or 1 degree warmer, mean January air temperatures at least 2 degrees colder). Two River Thames MIS11 sites (Ebbsfleet and Swanscombe) have yielded MPC results indicating summers up to 1.5 degrees warmer and winters at least 5 degrees colder than today. British early Middle Pleistocene sites record the earliest human presence in Europe North of the Alps. At Boxgrove (MIS13), well-known for its rich record of human activity (stone tools and butchered bones), combined ostracod and herpetile MCR results indicate summers within 3 degrees (above or below) of present day values, but winters at least 2 degrees colder, consistent with the mutual consensus of beetle and ostracod MCR results from another MIS13 human occupation site, Waverley Wood. Comparable MPC results have been obtained from older sites including Sugworth (MIS15?), Norton Subcourse and West Runton (both MIS17-15?); although none of these has yielded evidence of human presence they are potentially informative about the climatic context of Pakefield (MIS19 or 17), one of the earliest British sites with such evidence, where palaeoclimate reconstruction (warmer summers, winters similar to or colder than today) is based solely on the beetles. Likewise only the beetle MCR method has thus far been applied to the oldest known human occupation site in Britain, Happisburgh (MIS25 or 21), where similar summers and colder winters are again indicated; as yet no opportunity has arisen to check this result against another proxy. Human colonization of these sites by dispersal from more southerly populations had to contend with colder/longer winters, requiring greater dependence on meat for food because plant resources were only available in warmer months. Adaptive strategies likely involved using shelters and animal hides to keep warm, and eventually also fire (at least by MIS11), rather than seasonal migrations or physiological adaptations.

Argentinean Students' and Teachers' Conceptions of Day and Night: An Analysis in Relation to Astronomical Reference Systems

ERIC Educational Resources Information Center

Galperin, D.; Raviolo, A.

2015-01-01

This work analysed the evolution of day/night cycle conceptions held by students of different ages and teachers in the Patagonian region of Argentina. The research was based on drawings, written explanations and semi-structured individual interviews. The results showed that both teachers and students had significant comprehension problems. These…

A multi-proxy intercomparison of environmental change in two maar lake records from central Turkey during the last 14 ka

NASA Astrophysics Data System (ADS)

Roberts, C. Neil; Allcock, Samantha L.; Arnaud, Fabien; Dean, Jonathan R.; Eastwood, Warren J.; Jones, Matthew D.; Leng, Melanie J.; Metcalfe, Sarah E.; Malet, Emmanuel; Woodbridge, Jessie; Yiǧitbaşıoǧlu, Hakan

2016-04-01

Individual palaeoenvironmental records are a combination of regional-scale (e.g. climatic) and local factors. In order to separate these signals, we compare multiple proxies from two nearby maar lake records, on the assumption that common signals are due to regional-scale forcing. On the other side, we infer that residual signals are likely to be local and site-specific, rather than reflecting regional climate changes. A new core sequence from Nar lake has been dated by varve counting and U-Th as covering the last 13,800 years (Dean et al., 2015; Roberts et al., 2016). Periods of marked dryness are associated with peaks in Mg/dolomite, elevated Diatom-Inferred Electrical Conductivity, an absence of laminated sediments, and low Quercus/chenopod ratios. These conditions occurred during the Late-Glacial stadial, at 4.3-3.7 and 3.2-2.6 ka BP. Wet phases occurred during the early Holocene and again 1.5-0.6 ka, characterised by negative δ18O values, calcite precipitation, high Ca/Sr ratios, a high % of planktonic diatoms, laminated sediments, and high Quercus/chenopod ratios. Comparison with the independently dated record from Eski Acıgöl (Roberts et al., 2001) shows good correspondence for many proxies, especially for δ18O. A ranking of multiple proxies shows the worst correspondence is for clastic lithogenic elements (e.g. Ti flux). Differences between the two lake records are caused by basin infilling at Eski Acıgöl, which fails to register climatic changes during the last 2 ka, and to catchment erosion and increased flux of lithogenic elements into Nar lake; this is catchment-specific and primarily anthropogenic rather than climatic in origin. In separating a regional signal from site-specific "noise", two lakes may therefore be better than one. Dean, J.R. et al. 2015 Eastern Mediterranean hydroclimate over the late glacial and Holocene, reconstructed from the sediments of Nar lake, central Turkey, using stable isotopes and carbonate mineralogy. Quaternary Science Reviews 124, 162-174. Roberts, N et al. 2001 The tempo of Holocene climatic change in the eastern Mediterranean region: new high-resolution crater-lake sediment data from central Turkey. The Holocene 11, 721-736. Roberts, N., et al 2016 in press, A tale of two lakes: a multi-proxy comparison of Late Glacial and Holocene environmental change in Cappadocia, Turkey. Journal of Quaternary Science

Freshwater gastropods diversity hotspots: three new species from the Uruguay River (South America)

PubMed Central

de Lucía, Micaela

2016-01-01

Background: The Atlantic Forest is globally one of the priority ecoregions for biodiversity conservation. In Argentina, it is represented by the Paranense Forest, which covers a vast area of Misiones Province between the Paraná and Uruguay rivers. The Uruguay River is a global hotspot of freshwater gastropod diversity, here mainly represented by Tateidae (genus Potamolithus) and to a lesser extent Chilinidae. The family Chilinidae (Gastropoda, Hygrophila) includes 21 species currently recorded in Argentina, and three species in the Uruguay River. The species of Chilinidae occur in quite different types of habitats, but generally in clean oxygenated water recording variable temperature ranges. Highly oxygenated freshwater environments (waterfalls and rapids) are the most vulnerable continental environments. We provide here novel information on three new species of Chilinidae from environments containing waterfalls and rapids in the Uruguay River malacological province of Argentina. Materials and Methods: The specimens were collected in 2010. We analyzed shell, radula, and nervous and reproductive systems, and determined the molecular genetics. The genetic distance was calculated for two mitochondrial markers (cytochrome c oxidase subunit I–COI- and cytochrome b -Cyt b-) for these three new species and the species recorded from the Misionerean, Uruguay River and Lower Paraná-Río de la Plata malacological provinces. In addition, the COI data were analyzed phylogenetically by the neighbor-joining and Bayesian inference techniques. Results: The species described here are different in terms of shell, radula and nervous and reproductive systems, mostly based on the sculpture of the penis sheath. Phylogenetic analyses grouped the three new species with those present in the Lower Paraná-Río de la Plata and Uruguay River malacological provinces. Discussion: Phylogenetic analyses confirm the separation between the Uruguay River and the Misionerean malacological provinces in northeast Argentina. These new endemic species from the Uruguay River add further support to the suggestion that this river is a diversity hotspot of freshwater gastropods (with 54 species present in this basin, 15 of them endemic). These endemic species from environments with rapids and waterfalls should be taken into account by government agencies before the construction of dams that modify those ecologic niches in the Uruguay River. PMID:27326385

Carbon and nitrogen isotope composition of core catcher samples from the ICDP deep drilling at Laguna Potrok Aike (Patagonia, Argentina)

NASA Astrophysics Data System (ADS)

Luecke, Andreas; Wissel, Holger; Mayr*, Christoph; Oehlerich, Markus; Ohlendorf, Christian; Zolitschka, Bernd; Pasado Science Team

2010-05-01

The ICDP project PASADO aims to develop a detailed paleoclimatic record for the southern part of the South American continent from sediments of Laguna Potrok Aike (51°58'S, 70°23'W), situated in the Patagonian steppe east of the Andean cordillera and north of the Street of Magellan. The precursor project SALSA recovered the Holocene and Late Glacial sediment infill of Laguna Potrok Aike and developed the environmental history of the semi-arid Patagonian steppe by a consequent interdisciplinary multi-proxy approach (e.g. Haberzettl et al., 2007). From September to November 2008 the ICDP deep drilling took place and successfully recovered in total 510 m of sediments from two sites resulting in a composite depth of 106 m for the selected main study Site 2. A preliminary age model places the record within the last 50.000 years. During the drilling campaign, the core catcher content of each drilled core run (3 m) was taken as separate sample to be shared and distributed between involved laboratories long before the main sampling party. A total of 70 core catcher samples describe the sediments of Site 2 and will form the base for more detailed investigations on the palaeoclimatic history of Patagonia. We here report on the organic carbon and nitrogen isotope composition of bulk sediment and plant debris of the core catcher samples. Similar investigations were performed for Holocene and Late Glacial sediments of Laguna Potrok Aike revealing insights into the organic matter dynamics of the lake and its catchment as well as into climatically induced hydrological variations with related lake level fluctuations (Mayr et al., 2009). The carbon and nitrogen content of the core catcher fine sediment fraction (<200 µm) is low to very low (around 1 % and 0.1 %, respectively) and requires particular attention in isotope analysis. The carbon isotope composition shows comparably little variation around a value of -26.0 per mil. The positive values of the Holocene and the Late Glacial (up to 22.0 per mil) are only sporadically reached down core. Compared to this, separated moss debris is remarkably 13C depleted with a minimum at 31.5 per mil. The nitrogen isotope ratios of glacial Laguna Potrok Aike sediments are lower (2.5 per mil) than those of the younger part of the record. The core catcher samples indicate several oscillations between 0.5 and 3.5 per mil. Data suggest a correlation between nitrogen isotopes and C/N ratios, but no linear relation between carbon isotopes and carbon content and an only weak relationship between carbon and nitrogen isotopes. Increasing nitrogen isotope values from 8000 cm downwards could probably be related to changed environmental conditions of Marine Isotope Stage 3 (MIS 3) compared to Marine Isotope Stage 2 (MIS 2). This will be further evaluated with higher resolution from the composite profile including a detailed study of discrete plant debris layers. References Haberzettl, T. et al. (2007). Lateglacial and Holocene wet-dry cycles in southern Patagonia: chronology, sedimentology and geochemistry of a lacustrine record from Laguna Potrok Aike, Argentina. The Holocene, 17: 297-310. Mayr, C. et al. (2009). Isotopic and geochemical fingerprints of environmental changes during the last 16,000 years on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina). Journal of Paleolimnology, 42: 81-102.

A comparison of proxy performance in coral biodiversity monitoring

NASA Astrophysics Data System (ADS)

Richards, Zoe T.

2013-03-01

The productivity and health of coral reef habitat is diminishing worldwide; however, the effect that habitat declines have on coral reef biodiversity is not known. Logistical and financial constraints mean that surveys of hard coral communities rarely collect data at the species level; hence it is important to know if there are proxy metrics that can reliably predict biodiversity. Here, the performances of six proxy metrics are compared using regression analyses on survey data from a location in the northern Great Barrier Reef. Results suggest generic richness is a strong explanatory variable for spatial patterns in species richness (explaining 82 % of the variation when measured on a belt transect). The most commonly used metric of reef health, percentage live coral cover, is not positively or linearly related to hard coral species richness. This result raises doubt as to whether management actions based on such reefscape information will be effective for the conservation of coral biodiversity.

Where Am I? Location Archetype Keyword Extraction from Urban Mobility Patterns

PubMed Central

Kostakos, Vassilis; Juntunen, Tomi; Goncalves, Jorge; Hosio, Simo; Ojala, Timo

2013-01-01

Can online behaviour be used as a proxy for studying urban mobility? The increasing availability of digital mobility traces has provided new insights into collective human behaviour. Mobility datasets have been shown to be an accurate proxy for daily behaviour and social patterns, and behavioural data from Twitter has been used to predict real world phenomena such as cinema ticket sale volumes, stock prices, and disease outbreaks. In this paper we correlate city-scale urban traffic patterns with online search trends to uncover keywords describing the pedestrian traffic location. By analysing a 3-year mobility dataset we show that our approach, called Location Archetype Keyword Extraction (LAKE), is capable of uncovering semantically relevant keywords for describing a location. Our findings demonstrate an overarching relationship between online and offline collective behaviour, and allow for advancing analysis of community-level behaviour by using online search keywords as a practical behaviour proxy. PMID:23704964

Where am I? Location archetype keyword extraction from urban mobility patterns.

PubMed

Kostakos, Vassilis; Juntunen, Tomi; Goncalves, Jorge; Hosio, Simo; Ojala, Timo

2013-01-01

Can online behaviour be used as a proxy for studying urban mobility? The increasing availability of digital mobility traces has provided new insights into collective human behaviour. Mobility datasets have been shown to be an accurate proxy for daily behaviour and social patterns, and behavioural data from Twitter has been used to predict real world phenomena such as cinema ticket sale volumes, stock prices, and disease outbreaks. In this paper we correlate city-scale urban traffic patterns with online search trends to uncover keywords describing the pedestrian traffic location. By analysing a 3-year mobility dataset we show that our approach, called Location Archetype Keyword Extraction (LAKE), is capable of uncovering semantically relevant keywords for describing a location. Our findings demonstrate an overarching relationship between online and offline collective behaviour, and allow for advancing analysis of community-level behaviour by using online search keywords as a practical behaviour proxy.

Identification of human intestinal parasites affecting an asymptomatic peri-urban Argentinian population using multi-parallel quantitative real-time polymerase chain reaction.

PubMed

Cimino, Rubén O; Jeun, Rebecca; Juarez, Marisa; Cajal, Pamela S; Vargas, Paola; Echazú, Adriana; Bryan, Patricia E; Nasser, Julio; Krolewiecki, Alejandro; Mejia, Rojelio

2015-07-17

In resource-limited countries, stool microscopy is the diagnostic test of choice for intestinal parasites (soil-transmitted helminths and/or intestinal protozoa). However, sensitivity and specificity is low. Improved diagnosis of intestinal parasites is especially important for accurate measurements of prevalence and intensity of infections in endemic areas. The study was carried out in Orán, Argentina. A total of 99 stool samples from a local surveillance campaign were analyzed by concentration microscopy and McMaster egg counting technique compared to the analysis by multi-parallel quantitative real-time polymerase chain reaction (qPCR). This study compared the performance of qPCR assay and stool microscopy for 8 common intestinal parasites that infect humans including the helminths Ascaris lumbricoides, Ancylostoma duodenale, Necator americanus, Strongyloides stercoralis, Trichuris trichiura, and the protozoa Giardia lamblia, Cryptosporidium parvum/hominis, and Entamoeba histolytica, and investigated the prevalence of polyparasitism in an endemic area. qPCR showed higher detection rates for all parasites as compared to stool microscopy except T. trichiura. Species-specific primers and probes were able to distinguish between A. duodenale (19.1%) and N. americanus (36.4%) infections. There were 48.6% of subjects co-infected with both hookworms, and a significant increase in hookworm DNA for A. duodenale versus N. americanus (119.6 fg/μL: 0.63 fg/μL, P < 0.001) respectively. qPCR outperformed microscopy by the largest margin in G. lamblia infections (63.6% versus 8.1%, P < 0.05). Polyparasitism was detected more often by qPCR compared to microscopy (64.7% versus 24.2%, P < 0.05). Multi-parallel qPCR is a quantitative molecular diagnostic method for common intestinal parasites in an endemic area that has improved diagnostic accuracy compared to stool microscopy. This first time use of multi-parallel qPCR in Argentina has demonstrated the high prevalence of intestinal parasites in a peri-urban area. These results will contribute to more accurate epidemiological survey, refined treatment strategies on a public scale, and better health outcomes in endemic settings.

Tobacco smoking patterns and differential food effects on prostate and breast cancers among smokers and nonsmokers in Córdoba, Argentina.

PubMed

Román, María D; Niclis, Camila; Tumas, Natalia; Díaz, María Del Pilar; Osella, Alberto R; Muñoz, Sonia E

2014-07-01

The aim of this study was to estimate the effect of diet on prostate and breast cancer (PC and BC) risks in smokers and nonsmokers and to explore the effect modification between smoking and dietary patterns. PC or BC incidence rates were assessed spatially according to tobacco exposure, age-adjusted standardization using lung cancer mortality as a proxy. Two case-control studies were carried out in Argentina (2008-2012). Participants were interviewed about their diet, smoking habits, and other lifestyle factors. Multilevel models were fitted including family history of cancer as the random intercept for the second level, and diet and lifestyle variables as covariates. Tobacco exposure was aggregated spatially. Family history of cancer significantly accounts for PC and BC. In smokers, high intake of fat meat increased PC and BC risks [odds ratio (OR) 1.56, 95% confidence interval (CI) 0.81-3.05 and OR 6.01, 95% CI 1.99-8.19, respectively]. PC and BC risks were also greater in smokers with high intakes of fatty foods (OR 1.95, 95% CI 1.09-3.50 and OR 24.2, 95% CI 0.82-7.21, respectively). Moderate intake of nonstarchy vegetables and risk of PC were inversely associated in nonsmokers (OR 0.55, 95% CI 0.20-1.48). In smoker women, BC risk was associated with sweet drink consumption (OR 2.96, 95% CI 1.10-7.92) and ethanol intake (OR 5.15, 95% CI 1.88-14.16). Spatial distributions of cancer incidence rates match those of tobacco exposure. Differential effects of diet on PC and BC risks were found in smokers and nonsmokers.

Hydrogen stable isotopes from hydrated volcanic glass record orogenic growth and climate change at the eastern Puna Plateau margin, NW Argentina

NASA Astrophysics Data System (ADS)

Pingel, H.; Mulch, A.; Rohrmann, A.; Alonso, R. N.; Strecker, M. R.

2015-12-01

Intermontane basin strata along the E flanks of the Puna Plateau in NW Argentina are ideal archives to investigate the interaction between tectonics, topography, and changes in climate. In particular, these strata record the fragmentation of a formerly contiguous foreland by range uplifts, ensuing intra-basin deformation, and surface uplift. These changes were often accompanied by a transition from humid to semiarid conditions as windward range uplift exceeded orographic threshold elevations. The E Andean flanks comprise steep gradients in topography, rainfall, and surface-process rates. Rainfall is focused along the E flanks of the plateau, while the orogen interior is arid. These gradients are mirrored by the stable isotope ratios of modern rainfall, and therefore, in the stable isotope composition of proxy materials that incorporate this water. We present D/H ratios of volcanic glass (δDg) from dated tuffs in Mio-Pleistocene sediments of intermontane basins in the Eastern Cordillera between ~23 and 26°S (Humahuaca, Toro, and Angastaco basins). We document a strong co-varying relationship between tectono-sedimentary events in the basins and corresponding δDg values. Initial D-depletion trends in the Toro and Angastaco basins constrains the onset of surface uplift to 6.5 and 7 Ma, respectively. Strong positive δDg shifts of >15‰ in Humahuaca at ~3 Ma and <2 Ma in the Toro basin are apparently caused by enhanced evaporation. In this tectonic setting the observed relationships may be related to the attainment of orographic threshold conditions and ensuing hinterland aridification. δDg values in Angastaco, additionally, appear to be episodically influenced by enhanced convective rainfall during the Plio-Pleistocene, similar to modern conditions.

Multi-scale controls of historical forest-fire regimes: new insights from fire-scar networks

Treesearch

Donald A. Falk; Emily K. Heyerdahl; Peter M. Brown; Calvin Farris; Peter Z. Fule; Donald McKenzie; Thomas W. Swetnam; Alan H. Taylor; Megan L. Van Horne

2011-01-01

Anticipating future forest-fire regimes under changing climate requires that scientists and natural resource managers understand the factors that control fire across space and time. Fire scars—proxy records of fires, formed in the growth rings of long-lived trees—provide an annually accurate window into past low-severity fire regimes. In western North America, networks...

A 2000-yr-long multi-proxy lacustrine record from eastern Baffin Island, Arctic Canada reveals first millennium AD cold period

NASA Astrophysics Data System (ADS)

Thomas, Elizabeth K.; Briner, Jason P.; Axford, Yarrow; Francis, Donna R.; Miller, Gifford H.; Walker, Ian R.

2011-05-01

We generate a multi-proxy sub-centennial-scale reconstruction of environmental change during the past two millennia from Itilliq Lake, Baffin Island, Arctic Canada. Our reconstruction arises from a finely subsectioned 210Pb- and 14C-dated surface sediment core and includes measures of organic matter (e.g., chlorophyll a; carbon-nitrogen ratio) and insect (Diptera: Chironomidae) assemblages. Within the past millennium, the least productive, and by inference coldest, conditions occurred ca. AD 1700-1850, late in the Little Ice Age. The 2000-yr sediment record also reveals an episode of reduced organic matter deposition during the 6th-7th century AD; combined with the few other records comparable in resolution that span this time interval from Baffin Island, we suggest that this cold episode was experienced regionally. A comparable cold climatic episode occurred in Alaska and western Canada at this time, suggesting that the first millennium AD cold climate anomaly may have occurred throughout the Arctic. Dramatic increases in aquatic biological productivity at multiple trophic levels are indicated by increased chlorophyll a concentrations since AD 1800 and chironomid concentrations since AD 1900, both of which have risen to levels unprecedented over the past 2000 yr.

A multi-proxy paleolimnological reconstruction of Holocene climate conditions in the Great Basin, United States

NASA Astrophysics Data System (ADS)

Reinemann, Scott A.; Porinchu, David F.; Bloom, Amy M.; Mark, Bryan G.; Box, Jason E.

2009-11-01

A sediment core spanning ˜ 7000 cal yr BP recovered from Stella Lake, a small sub-alpine lake located in Great Basin National Park, Nevada, was analyzed for subfossil chironomids (non-biting midges), diatoms, and organic content (estimated by loss-on-ignition (LOI)). Subfossil chironomid analysis indicates that Stella Lake was characterized by a warm, middle Holocene, followed by a cool "Neoglacial" period, with the last two millennia characterized by a return to warmer conditions. Throughout the majority of the core the Stella Lake diatom-community composition is dominated by small, periphytic taxa which are suggestive of shallow, cool, alkaline, oligotrophic waters with extensive seasonal ice cover. A reconstruction of mean July air temperature (MJAT) was developed by applying a midge-based inference model for MJAT (two-component WA-PLS) consisting of 79 lakes and 54 midge taxa ( rjack2 = 0.55, RMSEP = 0.9°C). Comparison of the chironomid-inferred temperature record to existing regional paleoclimate reconstructions suggests that the midge-inferred temperatures correspond well to regional patterns. This multi-proxy record provides valuable insight into regional Holocene climate and environmental conditions by providing a quantitative reconstruction of peak Holocene warmth and aquatic ecosystem response to these changes in the Great Basin, a region projected to experience increased aridity and higher temperatures.

Large-Scale Features of Pliocene Climate: Results from the Pliocene Model Intercomparison Project

NASA Technical Reports Server (NTRS)

Haywood, A. M.; Hill, D.J.; Dolan, A. M.; Otto-Bliesner, B. L.; Bragg, F.; Chan, W.-L.; Chandler, M. A.; Contoux, C.; Dowsett, H. J.; Jost, A.;

Taxonomy of the genus Lycalopex (Carnivora: Canidae) in Argentina

USGS Publications Warehouse

Zunino, G.E.; Vaccaro, O.B.; Canevari, M.; Gardner, A.L.

1995-01-01

Previously treated as species of Pseudalopex, Argentine members of the genus Lycalopex (L. griseus, L. gymnocercus, and L. culpaeus) are examined to clarify the taxonomic status of each named form. Principal components analyses of 26 cranial measurements of 151 adult specimens and 11 pelage characters of 111 specimens, clearly distinguish L. culpaeus from the other two taxa. Lycalopex griseus and L. gymnocercus show clinal variation in cranial measurements and pelage characters. Qualitative cranial characters, used as diagnostic for L. griseus and L. gymnocercus, revealed great nongeographic variation. We conclude that L. griseus and L. gymnocercus are conspecific, and should be known as L. gymnocercus. Therefore, we recognize only two species of the genus Lycalopex (L. culpaeus and L. gymnocercus) in Argentina. We also use this opportunity to review synonymies of the recognized species of Lycalopex.

Queering abortion rights: notes from Argentina.

PubMed

Sutton, Barbara; Borland, Elizabeth

2018-03-06

In recent years, there have been calls in activist spaces to 'queer' abortion rights advocacy and to incorporate non-normative notions of gender identity and sexuality into abortion struggles and services. Argentina provides an interesting site in which to examine these developments, since there is a longstanding movement for abortion rights in a context of illegal abortion and a recent ground-breaking Gender Identity Law that recognises key trans rights. In this paper, we analyse public documents from the abortion rights movement's main coalition - the National Campaign for the Right to Legal, Safe and Free Abortion - alongside interviews with 19 Campaign activists to examine shifts and tensions in contemporary abortion rights activism. We trace the incorporation of trans-inclusive language into the newly proposed abortion rights bill and conclude by pointing to contextual factors that may limit or enhance the further queering of abortion rights.

Social Determinants of Health and Tobacco Use in Five Low and Middle-Income Countries - Results from the Global Adult Tobacco Survey (GATS), 2011 - 2012.

PubMed

Tee, Guat Hiong; Aris, Tahir; Rarick, James; Irimie, Sorina

2016-01-01

Tobacco consumption continues to be the leading cause of preventable deaths globally. The objective of this study was to examine the associaton of selected socio-demographic variables with current tobacco use in five countries that participated in the Phase II Global Adult Tobacco Survey in 2011 - 2012. We analysed internationally comparable representative household survey data from 33,482 respondents aged ≥ 15 years in Indonesia, Malaysia, Romania, Argentina and Nigeria for determinants of tobacco use within each country. Socio-demographic variables analysed included gender, age, residency, education, wealth index and awareness of smoking health consequences. Current tobacco use was defined as smoking or use of smokeless tobacco daily or occasionally. The overall prevalence of tobacco use varied from 5.5% in Nigeria to 35.7% in Indonesia and was significantly higher among males than females in all five countries. Odds ratios for current tobacco use were significantly higher among males for all countries [with the greatest odds among Indonesian men (OR=67.4, 95% CI: 51.2-88.7)] and among urban dwellers in Romania. The odds of current tobacco use decreased as age increased for all countries except Nigeria where. The reverse was true for Argentina and Nigeria. Significant trends for decreasing tobacco use with increasing educational levels and wealth index were seen in Indonesia, Malaysia and Romania. Significant negative associations between current tobacco use and awareness of adverse health consequences of smoking were found in all countries except Argentina. Males and the socially and economically disadvantaged populations are at the greatest risk of tobacco use. Tobacco control interventions maybe tailored to this segment of population and incorporate educational interventions to increase knowledge of adverse health consequences of smoking.

Improving dynamic phytoplankton reserve-utilization models with an indirect proxy for internal nitrogen.

PubMed

Malerba, Martino E; Heimann, Kirsten; Connolly, Sean R

2016-09-07

Ecologists have often used indirect proxies to represent variables that are difficult or impossible to measure directly. In phytoplankton, the internal concentration of the most limiting nutrient in a cell determines its growth rate. However, directly measuring the concentration of nutrients within cells is inaccurate, expensive, destructive, and time-consuming, substantially impairing our ability to model growth rates in nutrient-limited phytoplankton populations. The red chlorophyll autofluorescence (hereafter "red fluorescence") signal emitted by a cell is highly correlated with nitrogen quota in nitrogen-limited phytoplankton species. The aim of this study was to evaluate the reliability of including flow cytometric red fluorescence as a proxy for internal nitrogen status to model phytoplankton growth rates. To this end, we used the classic Quota model and designed three approaches to calibrate its model parameters to data: where empirical observations on cell internal nitrogen quota were used to fit the model ("Nitrogen-Quota approach"), where quota dynamics were inferred only from changes in medium nutrient depletion and population density ("Virtual-Quota approach"), or where red fluorescence emission of a cell was used as an indirect proxy for its internal nitrogen quota ("Fluorescence-Quota approach"). Two separate analyses were carried out. In the first analysis, stochastic model simulations were parameterized from published empirical relationships and used to generate dynamics of phytoplankton communities reared under nitrogen-limited conditions. Quota models were fitted to the dynamics of each simulated species with the three different approaches and the performance of each model was compared. In the second analysis, we fit Quota models to laboratory time-series and we calculate the ability of each calibration approach to describe the observed trajectories of internal nitrogen quota in the culture. Results from both analyses concluded that the Fluorescence-Quota approach including per-cell red fluorescence as a proxy of internal nitrogen substantially improved the ability of Quota models to describe phytoplankton dynamics, while still accounting for the biologically important process of cell nitrogen storage. More broadly, many population models in ecology implicitly recognize the importance of accounting for storage mechanisms to describe the dynamics of individual organisms. Hence, the approach documented here with phytoplankton dynamics may also be useful for evaluating the potential of indirect proxies in other ecological systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

77 FR 21968 - Honey From Argentina: Rescission of Countervailing Duty Administrative Review

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-12

... DEPARTMENT OF COMMERCE International Trade Administration [C-357-813] Honey From Argentina... Argentina. See Notice of Countervailing Duty Order: Honey From Argentina, 66 FR 63673 (December 10, 2001... review of the countervailing duty order on honey from Argentina for the period January 1, 2011, through...

76 FR 16609 - Honey From Argentina: Rescission of Countervailing Duty Administrative Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-24

... DEPARTMENT OF COMMERCE International Trade Administration [C-357-813] Honey From Argentina... administrative review of the countervailing duty order on honey from Argentina for the period January 1, 2010... order on honey from Argentina. See Notice of Countervailing Duty Order: Honey From Argentina, 66 FR...

Geochemical fingerprint of desert surface sediments and aeolian dust exported from southern South America

NASA Astrophysics Data System (ADS)

Gili, S.; Gaiero, D. M.; Jweda, J.; Koestner, E.; Chemale, F.; Kaplan, M. R.; Goldstein, S. L.

2012-12-01

Wind-transported dust is a tracer of atmospheric circulation and also provides important information about the climatic conditions prevailing in dust source areas. Understanding the origin of mineral dust deposited in different environments (e.g., continent, ocean, polar ice sheet) and the variability of its concentration and composition, can be used as a proxy for the interpretation of the wind systems characteristics and probable changes in the atmospheric circulation patterns. In order to improve the atmospheric circulation models developed for the Southern Hemisphere, it is necessary to increase the understanding of the characteristics of the South American dust sources. Prospero et al., (2002), showed the existence of three present-day persist dust sources in South America: Patagonia (39°-52°S), central-western Argentina (26°-33°S), and the Puna-Altiplano plateau (19°-26°S). An important question to be addressed is whether these dust sources were also important during the last glacial-interglacial cycles. In most cases, researchers working in the reconstruction of paleo-environments in the Southern Hemisphere have employed sparse geochemical and isotopic data from southern South American samples. As a consequence, there are no regional or systematic studies that define their geochemical "fingerprints" of likely sources. The main goal of this work is to identify the "fingerprints" of materials exported from these areas by means of rare earth elements (REEs) and Sr-Nd-Pb-isotopes measured in surface sediments (topsoils) and mineral dust samples. Samples (n=86) were taken across the "arid diagonal" of southern South America in a N-S transect from Uyuni (20°39'S, 68°11'W, Bolivia) to Bahia Blanca (38°43'S, 62°15'W, Argentina) representing different geomorphologic environments: e.g., ephemeral lakes, lowland areas, edges of salt flats, alluvial fans, dunes, etc. Preliminary data indicate the existence of a heterogeneous chemical/isotopic signature along the "arid diagonal": a) the Altiplano and Puna have chemical and isotopic compositions inherited from the large volume of Cenozoic ignimbrites and from the Late Paleozoic granitoids (south of 21°S), respectively, b) the potential dust source in central-western Argentina appears to show a separate geochemical fingerprint explained basically by the mixing of metamorphic rocks from Eastern Sierras Pampeanas, Central Argentina and, c) dust from Patagonia with clear chemical/isotopic signatures characteristic of the Quaternary volcanism (Gaiero et al., 2004; 2007). These results are promising, as they would enable the identification of the main dust source regions in provenance studies of different paleoclimatic records (Pampean loess, Antarctic ice cores, Atlantic and Southern oceans, etc).

The volcanic double event at the dawn of the Dark Ages

NASA Astrophysics Data System (ADS)

Toohey, Matthew; Sigl, Michael; Krüger, Kirstin; Stordal, Frode; Svensen, Henrik

2016-04-01

Documentary records report dimming of the sun by a mysterious dust cloud covering Europe for 12-18 months in 536-537 CE, which was followed by a general climatic downturn and global societal decline. Tree rings and other climate proxies have corroborated the occurrence of this event as well as characterized its extent and duration, but failed to trace its origin. New volcanic timeseries, based on a multi-disciplinary approach that integrates novel, global-scale time markers with state-of-the-art continuous ice core aerosol measurements, automated objective ice-core layer counting, tephra analyses, and detailed examination of historical archives, show unequivocally that the 536-540 climate anomaly was concurrent with two or more major volcanic eruptions, with the largest eruptions likely occurring in the years 536 and 540 CE. Using a coupled aerosol-climate model, with eruption parameters constrained by ice core records and historical observations of the aerosol cloud, we reconstruct the radiative forcing resulting from the 536/540 CE eruption sequence. Comparing with existing reconstructions of the volcanic forcing over the past 1200 years, we estimate that the decadal-scale Northern Hemisphere (NH) extra-tropical radiative forcing from this volcanic "double event" was larger than that of any known period. Earth system model simulations including the volcanic forcing are used to explore the temperature and precipitation anomalies associated with the eruptions, and compared to available proxy records, including maximum latewood density (MXD) temperature reconstructions. Special attention is placed on the decadal persistence of the cooling signal in tree rings, and whether the climate model simulations reproduce such long-term climate anomalies. Finally, the climate model results are used to explore the probability of socioeconomic crisis resulting directly from the volcanic radiative forcing in different regions of the world.

A High-Resolution Record of Holocene Climate Variability from a Western Canadian Coastal Inlet

NASA Astrophysics Data System (ADS)

Dallimore, A.; Thomson, R. E.; Enkin, R. J.; Kulikov, E. A.; Bertram, M. A.; Wright, C. A.; Southon, J. R.; Barrie, J. V.; Baker, J.; Pienitz, R.; Calvert, S. E.; Chang, A. S.; Pedersen, T. F.

2004-12-01

Conditions within the Pacific Ocean have a major effect on the climate of northwestern North America. High resolution records of present and past northeast Pacific climate are revealed in our multi-disciplinary study of annually laminated marine sediments from anoxic coastal inlets of British Columbia. Past climate conditions for the entire Holocene are recorded in the sediment record contained in a 40 meter, annually laminated marine sediment core taken in Effingham Inlet, on the west coast of Vancouver Island, British Columbia, from the French ship the Marion Dufresne, as part of the international IMAGES program. By combining our eight year continuous instrument record of modern coastal ocean dynamics and climate with high-resolution analysis of depositional processes, we have been able to develop proxy measurements of past climatic and oceanographic changes on annual to millennial time scales. Results indicate that regional climate has oscillated on a variety of time scales throughout the Holocene. At times, climatic change has been dramatically rapid. We are also developing digital methods for statistical time-series analyses of physical sediment properties through the Holocene in order to obtain a more objective quantitative approach for detecting cyclicity in our data. Results of the time series analysis of lamination thickness reveals statistically significant spectral peaks of climate scale variability at established decadal to century time scales. These in turn may be related to solar cycles and quasi-cyclical ocean processes such as the Pacific Decadal Oscillation. However, the annually laminated time series are periodically interrupted by massive mud intervals which are related to bottom currents and at times paleo-seismic events, illustrating the need for a full understanding of modern oceanographic and sedimentation processes, so an accurate proxy record of past climate can be established.

Potential Effects of Climate Change on the Water Level, Flora and Macro-fauna of a Large Neotropical Wetland

PubMed Central

Úbeda, Bárbara; Di Giacomo, Adrian S.; Neiff, Juan José; Loiselle, Steven A.; Guadalupe Poi, Alicia S.; Gálvez, José Ángel; Casco, Silvina; Cózar, Andrés

2013-01-01

Possible consequences of climate change in one of the world’s largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades. PMID:23874446

Potential effects of climate change on the water level, flora and macro-fauna of a large neotropical wetland.

PubMed

Úbeda, Bárbara; Di Giacomo, Adrian S; Neiff, Juan José; Loiselle, Steven A; Poi, Alicia S Guadalupe; Gálvez, José Ángel; Casco, Silvina; Cózar, Andrés

2013-01-01

Possible consequences of climate change in one of the world's largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades.

[Self-medication, self-prescription and medicating «by proxy» in paediatrics].

PubMed

Valenzuela Ortiz, María; Sánchez Ruiz-Cabello, Francisco Javier; Uberos, José; Checa Ros, Ana Fátima; Valenzuela Ortiz, Cristina; Augustín Morales, María Carmen; Muñoz Hoyos, Antonio

2017-05-01

Self-prescribing or medicating 'by proxy' is not an autonomous, free and voluntary decision in the case of children. On the contrary, in this case it is based on the subjective interpretation of symptoms made by the mother or by a third person who is legally responsible for the minor. In our opinion, to analyse this situation is of great importance in order to know the determining factors, perceptions, and realities related to this problem. Our proposal is to perform a prospective observational study for analysing maternal and familiar determinant factors related to self-prescribing and self-medicating 'by proxy' in paediatrics. A validated survey was developed to be applied to mothers of children aged 0 to 14 who are users of the Paediatric Emergency Department in a hospital. A total of 1,714 mothers were recruited in a random period of time. This sample included 345 mothers who exclusively self-medicated their children (case group), and 1,369 mothers (control group) who did not meet this requirement. The overall percentage of medicating 'by proxy' was 32.8%. There is a significant association between self-medicating and educational level of the mother, the number of children, and the birth order among siblings. Neither maternal age nor social-occupational level are related to this problem. Most frequently used drugs include antipyretics and 'anticatharrals', usually administered as a monotherapy. Our results seem to indicate that the educational level and the parental experience acquired with previous children could generate the required confidence in parents to choose the medication by themselves. Almost 85% of these drugs come from the 'home first-aid kit.' Copyright © 2016 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

Palaeoenvironmental reconstruction from Lake Iznik (W Turkey) and Üçaǧizli Cave (S Turkey) - implications for human dispersal in the Upper Palaeolithic along coastal Anatolia.

NASA Astrophysics Data System (ADS)

Viehberg, Finn A.; Assanov, Sergey; Kuhn, Steven; Reed, Jane; Ülgen, Umut B.; Namık Çaǧatay, M.; Melles, Martin

2013-04-01

Transcontinental dispersal of modern humans from the Near East to the Balkans in the Middle and Upper Palaeolithic is expected to have followed the coastline (i.e., Yarımburgaz, Karain and Üçaǧızlı caves). Lake Iznik is situated 80 km south of the Bosphorus (Western Turkey) close to the Marmara Sea. Here we retrieved a continuous sediment record covering the past ~40 ka cal BP. A multiproxy approach enabled us to reconstruct the environmental history. We included biological proxies i.e., diatoms, cladocerans and ostracods as biological proxies, but also physical and geochemical proxies were analysed. Geomorphological findings in the lake basin and geochemical analyses hint to changing lake water levels at least since 40 ka cal BP that lasted until c. 11 cal. kyr BP. This supports the theory of persisting dry climate conditions before the onset of the Holocene also inferred from geochemical sediment proxies (i.e., element analysis), diatoms and ostracod shell chemistry. The Upper Palaeolithic sequences (45-33 ka cal BP) at the Üçaǧızlı Cave (Hatay) yield clear evidence of the technological transition between Initial Upper Palaeolithic and Ahmarian, but also documents major shifts in diet of past hunting community. The identified animal remains in the cave sequence change from larger ungulates to smaller ungulates and increase in fish and shellfish. It is proposed that the compositional change in game is not solitarily caused by technology advances, but also by environmental and climatic changes as inferred from sediment archives of Lake Iznik.

Water-Level Reconstruction and its Implications for Late Pleistocene Paleontological Site Formation in Hoyo Negro, a Submerged Subterranean Pit in Quintana Roo, Mexico

NASA Astrophysics Data System (ADS)

Rissolo, D.; Reinhardt, E. G.; Collins, S.; Kovacs, S. E.; Beddows, P. A.; Chatters, J. C.; Nava Blank, A.; Luna Erreguerena, P.

2014-12-01

A massive pit deep within the now submerged cave system of Sac Actun, located along the central east coast of the Yucatan Peninsula, contains a diverse fossil assemblage of extinct megafauna as well as a nearly complete human skeleton. The inundated site of Hoyo Negro presents a unique and promising opportunity for interdisciplinary Paleoamerican and paleoenvironmental research in the region. Investigations have thus far revealed a range of associated features and deposits which make possible a multi-proxy approach to identifying and reconstructing the natural and cultural processes that have formed and transformed the site over millennia. Understanding water-level fluctuations (both related to, and independent from, eustatic sea level changes), with respect to cave morphology is central to understanding the movement of humans and animals into and through the cave system. Recent and ongoing studies involve absolute dating of human, faunal, macrobotanical, and geological samples; taphonomic analyses; and a characterization of site hydrogeology and sedimentological facies, including microfossil assemblages and calcite raft deposits.

The role of C3 and C4 grasses to interannual variability in remotely sensed ecosystem performance over the US Great Plains

USGS Publications Warehouse

Ricotta, C.; Reed, B.C.; Tieszen, L.T.

2003-01-01

Time integrated normalized difference vegetation index (??NDVI) derived from National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) multi-temporal imagery over a 10-year period (1989-1998) was used as a surrogate for primary production to investigate the impact of interannual climate variability on grassland performance for central and northern US Great Plains. First, the contribution of C3 and C4 species abundance to the major grassland ecosystems of the US Great Plains is described. Next, the relation between mean ??NDVI and the ??NDVI coefficient of variation (CV ??NDVI) used as a proxy for interranual climate variability is analysed. Results suggest that the differences in the long-term climate control over ecosystem performance approximately coincide with changes between C3- and C4-dominant grassland classes. Variation in remotely sensed net primary production over time is higher for the southern and western plains grasslands (primary C4 grasslands), whereas the C3-dominated classes in the northern and eastern portion of the US Great Plains, generally show lower CV ??NDVI values.

Among nonagenarians, congruence between self-rated and proxy-rated health was low but both predicted mortality.

PubMed

Vuorisalmi, Merja; Sarkeala, Tytti; Hervonen, Antti; Jylhä, Marja

2012-05-01

The congruence between self-rated global health (SRH) and proxy-rated global health (PRH), the factors associated with congruence between SRH and PRH, and their associations with mortality are examined using data from the Vitality 90+ study. The data consist of 213 pairs of subjects--aged 90 years and older--and proxies. The relationship between SRH and PRH was analyzed by chi-square test and Cohen's kappa. Logistic regression analysis was used to find out the factors that are associated with the congruence between health ratings. The association between SRH and PRH with mortality was studied using Cox proportional hazard models. The subjects rated their health more negatively than the proxies. Kappa value indicated only slight congruence between SRH and PRH, and they also predicted mortality differently. Good self-reported functional ability was associated with congruence between SRH and PRH. The results imply that the evaluation processes of SRH and PRH differ, and the measures are not directly interchangeable. Both measures are useful health indicators in very old age but SRH cannot be replaced by PRH in analyses. Copyright © 2012 Elsevier Inc. All rights reserved.

Megadroughts and Intensified Terrestrial Flooding - Underrated Consequences of Early Eocene Hyperthermals?

NASA Astrophysics Data System (ADS)

Plink-Bjorklund, P.; Birgenheier, L.; Golab, J.

2011-12-01

Here we present results of independent multi-proxy analyses of an Early Eocene sedimentary succession from the interior of the US, combining detailed sedimentologic and stratigraphic analyses with ichno-pedogenic analyses and stable carbon isotope analyses through 1000 m of river and lake deposits, across an area of ca 600 km2 in the Uinta Basin, Utah. This Early Eocene Climatic Optimum (ca 55.5-51.4 Myr ago) dataset is different from previously published terrestrial climate proxy analyses, in that we document the Palaeocene Eocene Thermal Maximum (PETM) as well as 6-8 post-PETM transient global warming events or hyperthermals by δ13Corg excursions, as well as river systems response to these events from the sedimentary record. Moreover, our dataset indicates that palaeosols and isotope values may in some cases only capture the long-term conditions, and are not able to reproduce the seasonality. We show that there are 6-8 Early Eocene hyperthermals that are climatically prominent enough to cause significant changes in the climate processes, as well as generate significant consequences to the river systems behaviour, recorded in the geological record. We show that in the continental interior of North America each of the Early Eocene transient global warming events or hyperthermals includes an onset period that reflects increased temperatures, weathering and sediment production, while the peaks of the hyperthermals indicate a shift to significantly intensified hydrological cycle with extreme conditions of prolonged megadroughts and short catastrophic terrestrial flooding episodes, followed by a recovery period. We demonstrate that only the PETM event exhibits a non-linear response to global warming, in that the system responded by alternations between increasing and decreasing seasonality during onset and offset, and has two distinct episodes of peak conditions. The PETM, and the H1, H2, I1, I2 events are distinct in both sedimentary and isotope record, whereas the youngest hyperthermals become successively more difficult to distinguish from the background conditions on both records. Thus, there is a long-term trend or transition from the most extreme conditions with prolonged megadroughts with seasonally dry river beds, and short catastrophic wet seasons with most extreme sediment production, erosion, deposition, and avulsion rates during the peak of the PETM, towards gradually milder conditions during the successive post-PETM hyperthermals. The peaks of the first three post-PETM hyperthermals (H1, H2, I1) are characterised by almost as severe conditions, as the PETM. The peaks of the following hyperthermals are successively less severe, but still reflect intensified seasonality, sediment production, deposition and avulsion rates. However, the peak conditions of these hyperthermals compare to the conditions during parts of onset or offset intervals of the PETM, rather than its peak.

77 FR 4763 - Honey From Argentina: Notice of Initiation of Antidumping Duty New Shipper Review

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-31

... DEPARTMENT OF COMMERCE International Trade Administration [A-357-812] Honey From Argentina: Notice... Argentina. See Notice of Antidumping Duty Order: Honey From Argentina, 66 FR 63672 (December 10, 2001...: Background On December 10, 2001, the Department published the antidumping duty order on honey from Argentina...

75 FR 23674 - Honey from Argentina: Final Results of Antidumping Duty Administrative Review and Determination...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-04

... DEPARTMENT OF COMMERCE International Trade Administration A-357-812 Honey from Argentina: Final... review of the antidumping duty order on honey from Argentina. See Honey from Argentina: Preliminary... preliminary results of the administrative review of the antidumping duty order on honey from Argentina for the...

Analyses of Sea Surface Height, Bottom Pressure and Acoustic Travel Time in the Japan/East Sea

DTIC Science & Technology

2006-01-01

ANALYSES OF SEA SURFACE HEIGHT, BOTTOM PRESSURE AND ACOUSTIC TRAVEL TIME IN THE JAPAN/EAST SEA BY YONGSHENG XU A DISSERTATION SUBMITTED IN PARTIAL...COVERED 00-00-2006 to 00-00-2006 4. TITLE AND SUBTITLE Analyses of Sea Surface Height, Bottom Pressure and Acoustic Travel Time in the Japan/East Sea...1999 to July 2001. The PIESs recorded hourly vertical acoustic travel time and pressure, which are respectively good proxies of baroclinic and

Hyper-spectral imaging: A promising tool for quantitative pigment analysis of varved lake sediments

NASA Astrophysics Data System (ADS)

Butz, Christoph; Grosjean, Martin; Tylmann, Wojciech

2015-04-01

Varved lake sediments are good archives for past environmental and climate conditions from annual to multi-millennial scales. Among other proxies, concentrations of sedimentary photopigments have been used for temperature reconstructions. However, obtaining well calibrated annually resolved records from sediments still remains challenging. Most laboratory methods used to analyse lake sediments require physical subsampling and are destructive in the process. Hence, temporal resolution and number of data are limited by the amount of material available in the core. Furthermore, for very low sediment accumulation rates annual subsampling is often very difficult or even impossible. To address these problems we explore hyper-spectral imaging as a non-destructive method to analyse lake sediments based on their reflectance spectra in the visible and near infrared spectrum. In contrast to other scanning methods like X-ray fluorescence, VIS/NIR reflectance spectrometry distinguishes between biogeochemical substances rather than single elements. Among others Rein (2003) has shown that VIS-RS can be used to detect relative concentrations of sedimentary photopigments (e.g. chlorins, carotenoids) and clay minerals. In this study hyper-spectral imaging is used to infer ecological proxy data from reflectance spectra of varved lake sediments. Hyper-spectral imaging permits the measurement of an entire sediment core in a single run at high spatial (30x30µm/pixel) and spectral resolutions (~2.8nm) within the visual to near infrared spectrum (400-1000nm). This allows the analysis of data time series and spatial mapping of sedimentary substances (e.g. chlorophylls/bacterio-chlorophylls and diagenetic products) at sub-varve scales. The method is demonstrated on two varved lake sediments from northern Poland showing the distributions of relative concentrations of two types of sedimentary pigments (Chlorophyll-a + derivatives and Bacterio-pheophytin-a) within individual varve years. The relative concentrations from the spectral data set have then been calibrated with absolute concentrations derived by High-Performance-Liquid-Chromatography (HPLC). This results in very high-resolution data sets of absolute sedimentary pigment concentrations suitable for the analysis of seasonal pigment variations.

77 FR 28570 - Honey From Argentina: Extension of Time Limit for the Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-15

... DEPARTMENT OF COMMERCE International Trade Administration [A-357-812] Honey From Argentina... administrative review for the 2009-2010 period of review (POR) of honey from Argentina. See Honey From Argentina... producers/exporters of honey from Argentina during the POR.\\1\\ \\1\\ See Preliminary Results for a detailed...

Geostatistical modelling of soil-transmitted helminth infection in Cambodia: do socioeconomic factors improve predictions?

PubMed

Karagiannis-Voules, Dimitrios-Alexios; Odermatt, Peter; Biedermann, Patricia; Khieu, Virak; Schär, Fabian; Muth, Sinuon; Utzinger, Jürg; Vounatsou, Penelope

2015-01-01

Soil-transmitted helminth infections are intimately connected with poverty. Yet, there is a paucity of using socioeconomic proxies in spatially explicit risk profiling. We compiled household-level socioeconomic data pertaining to sanitation, drinking-water, education and nutrition from readily available Demographic and Health Surveys, Multiple Indicator Cluster Surveys and World Health Surveys for Cambodia and aggregated the data at village level. We conducted a systematic review to identify parasitological surveys and made every effort possible to extract, georeference and upload the data in the open source Global Neglected Tropical Diseases database. Bayesian geostatistical models were employed to spatially align the village-aggregated socioeconomic predictors with the soil-transmitted helminth infection data. The risk of soil-transmitted helminth infection was predicted at a grid of 1×1km covering Cambodia. Additionally, two separate individual-level spatial analyses were carried out, for Takeo and Preah Vihear provinces, to assess and quantify the association between soil-transmitted helminth infection and socioeconomic indicators at an individual level. Overall, we obtained socioeconomic proxies from 1624 locations across the country. Surveys focussing on soil-transmitted helminth infections were extracted from 16 sources reporting data from 238 unique locations. We found that the risk of soil-transmitted helminth infection from 2000 onwards was considerably lower than in surveys conducted earlier. Population-adjusted prevalences for school-aged children from 2000 onwards were 28.7% for hookworm, 1.5% for Ascaris lumbricoides and 0.9% for Trichuris trichiura. Surprisingly, at the country-wide analyses, we did not find any significant association between soil-transmitted helminth infection and village-aggregated socioeconomic proxies. Based also on the individual-level analyses we conclude that socioeconomic proxies might not be good predictors at an aggregated large-scale analysis due to their large between- and within-village heterogeneity. Specific information of both the infection risk and potential predictors might be needed to obtain any existing association. The presented soil-transmitted helminth infection risk estimates for Cambodia can be used for guiding and evaluating control and elimination efforts. Copyright © 2014. Published by Elsevier B.V.

Mg/Ca and Sr/Ca as novel geochemical proxies for understanding sediment transport processes within coral reefs

NASA Astrophysics Data System (ADS)

Gacutan, J.; Vila-Concejo, A.; Nothdurft, L. D.; Fellowes, T. E.; Cathey, H. E.; Opdyke, B. N.; Harris, D. L.; Hamylton, S.; Carvalho, R. C.; Byrne, M.; Webster, J. M.

2017-10-01

Sediment transport is a key driver of reef zonation and biodiversity, where an understanding of sediment dynamics gives insights into past reef processes and allows the prediction of geomorphic responses to changing environmental conditions. However, modal conditions within the back-reef seldom promote sediment transport, hence direct observation is inherently difficult. Large benthic foraminifera (LBF) have previously been employed as 'tracers' to infer sediment transport pathways on coral reefs, as their habitat is largely restricted to the algal flat and post-mortem, their calcium carbonate test is susceptible to sediment transport forces into the back-reef. Foraminiferal test abundance and post-depositional test alteration have been used as proxies for sediment transport, although the resolution of these measures becomes limited by low test abundance and the lack of variation within test alteration. Here we propose the novel use of elemental ratios as a proxy for sediment transport. Two species, Baculogypsina sphaerulata and Calcarina capricornia, were analysed using a taphonomic index within One Tree and Lady Musgrave reefs, Great Barrier Reef (Australia). Inductively coupled plasma-atomic emission spectrometry (ICP-AES) was used to determine Mg/Ca and Sr/Ca and these ratios were compared with taphonomic data. Decreases in test Mg/Ca accompany increases in Sr/Ca in specimens from algal-flat to lagoonal samples in both species, mirroring trends indicated by taphonomic values, therefore indicating a relationship with test alteration. To delineate mechanisms driving changes in elemental ratios, back-scattered electron (BSE) images, elemental mapping and in situ quantitative spot analyses by electron microprobe microanalysis (EPMA) using wavelength dispersive X-ray spectrometers (WDS) were performed on un-altered algal flat and heavily abraded tests for both species. EPMA analyses reveal heterogeneity in Mg/Ca between spines and the test wall, implying the loss of appendages results in a decrease in Mg/Ca. BSE imaging and WDS elemental mapping provided evidence for cementation, facilitated by microbial-boring as the primary cause of increasing Sr/Ca. These novel proxies hold advantages over taphonomic measures and further provide a rapid method to infer sediment transport pathways within back-reef environments.

cm-scale variations of crystal orientation fabric in cold Alpine ice core from Colle Gnifetti

NASA Astrophysics Data System (ADS)

Kerch, Johanna; Weikusat, Ilka; Eisen, Olaf; Wagenbach, Dietmar; Erhardt, Tobias

2015-04-01

Analysis of the microstructural parameters of ice has been an important part of ice core analyses so far mainly in polar cores in order to obtain information about physical processes (e.g. deformation, recrystallisation) on the micro- and macro-scale within an ice body. More recently the influence of impurities and climatic conditions during snow accumulation on these processes has come into focus. A deeper understanding of how palaeoclimate proxies interact with physical properties of the ice matrix bears relevance for palaeoclimatic interpretations, improved geophysical measurement techniques and the furthering of ice dynamical modeling. Variations in microstructural parameters e.g. crystal orientation fabric or grain size can be observed on a scale of hundreds and tens of metres but also on a centimetre scale. The underlying processes are not necessarily the same on all scales. Especially for the short-scale variations many questions remain unanswered. We present results from a study that aims to investigate following hypotheses: 1. Variations in grain size and fabric, i.e. strong changes of the orientation of ice crystals with respect to the vertical, occur on a centimetre scale and can be observed in all depths of an ice core. 2. Palaeoclimate proxies like dust and impurities have an impact on the microstructural processes and thus are inducing the observed short-scale variations in grain size and fabric. 3. The interaction of proxies with the ice matrix leads to depth intervals that show correlating behaviour as well as ranges with anticorrelation between microstructural parameters and palaeoclimatic proxies. The respective processes need to be identified. Fabric Analyser measurements were conducted on more than 80 samples (total of 8 m) from different depth ranges of a cold Alpine ice core (72 m length) drilled in 2013 at Colle Gnifetti, Switzerland/Italy. Results were obtained by automatic image processing, providing estimates for grain size distributions and crystal orientation fabric, and comparison with data from continuous flow analysis of chemical impurities. A microstructural characterisation of the analysed core is presented with emphasis on the observed variations in crystal orientation fabric. The relevance of these results for palaeoclimate reconstruction and geophysical applications in ice are discussed.

Molluscan and Foraminiferan Paleoecological Reconstructions of Extreme Post-Glacial Seafloor Environments of the California Borderland

NASA Astrophysics Data System (ADS)

Moffitt, S. E.; Hill, T. M.; Kroeker, K.; Roopnarine, P. D.; Kennett, J.

2014-12-01

We have reconstructed paleoecological and climatic change in a Late Quaternary (16.1-3.4 ka) sediment core from the California margin (418 meters below sea level) of Santa Barbara Basin using quantitative analyses of Molluscan and Foraminiferan microfossils. This archive represents the first record of marine metazoan community ecology, and a comparison to a well-established biotic proxy (Foraminifera), through the climatic and oceanographic events of the most recent deglaciation. The high-resolution seafloor archive reveals strong coupling between orbital and millennial climatic episodes and the structure of shallow ocean ecosystems. Changes in the density and diversity of molluscs and foraminifera exhibit clear associations with climatic events that mark the deglacial episode, including rapid expansions and contractions of the Oxygen Minimum Zone and development of chemosynthetic bacterial mat communities. Molluscans occur discontinuously in only 28% of the sediment sequence, whereas foraminifera occur throughout. Multivariate statistical analyses of the community ecology assist with the interpretations of the multi-species paleoecological data and of processes that caused the variability. A surprising dominance of molluscan extremophiles (sulfidic Astrys permodesta and hypoxic Lucinoma aequizonatum) during cool, well oxygenated intervals reveals how such forms can thrive during inferred brief ephemeral extreme events. Hydrographic variability and bottom water flow, as well as the growth of benthic bacterial communities, determine where such extremophile communities dominate.

'Fish out of water': a cross-sectional study on the interaction between social and neighbourhood effects on weight management behaviours.

PubMed

Green, M A; Subramanian, S V; Strong, M; Cooper, C L; Loban, A; Bissell, P

2015-03-01

To analyse whether an individual's neighbourhood influences the uptake of weight management strategies and whether there is an interaction between individual socio-economic status and neighbourhood deprivation. Data were collected from the Yorkshire Health Study (2010-2012) for 27 806 individuals on the use of the following weight management strategies: 'slimming clubs', 'healthy eating', 'increasing exercise' and 'controlling portion size'. A multi-level logistic regression was fit to analyse the use of these strategies, controlling for age, sex, body mass index, education, neighbourhood deprivation and neighbourhood population turnover (a proxy for neighbourhood social capital). A cross-level interaction term was included for education and neighbourhood deprivation. Lower Super Output Area was used as the geographical scale for the areal unit of analysis. Significant neighbourhood effects were observed for use of 'slimming clubs', 'healthy eating' and 'increasing exercise' as weight management strategies, independent of individual- and area-level covariates. A significant interaction between education and neighbourhood deprivation was observed across all strategies, suggesting that as an area becomes more deprived, individuals of the lowest education are more likely not to use any strategy compared with those of the highest education. Neighbourhoods modify/amplify individual disadvantage and social inequalities, with individuals of low education disproportionally affected by deprivation. It is important to include neighbourhood-based explanations in the development of community-based policy interventions to help tackle obesity.

Memory matters: influence from a cognitive map on animal space use.

PubMed

Gautestad, Arild O

2011-10-21

A vertebrate individual's cognitive map provides a capacity for site fidelity and long-distance returns to favorable patches. Fractal-geometrical analysis of individual space use based on collection of telemetry fixes makes it possible to verify the influence of a cognitive map on the spatial scatter of habitat use and also to what extent space use has been of a scale-specific versus a scale-free kind. This approach rests on a statistical mechanical level of system abstraction, where micro-scale details of behavioral interactions are coarse-grained to macro-scale observables like the fractal dimension of space use. In this manner, the magnitude of the fractal dimension becomes a proxy variable for distinguishing between main classes of habitat exploration and site fidelity, like memory-less (Markovian) Brownian motion and Levy walk and memory-enhanced space use like Multi-scaled Random Walk (MRW). In this paper previous analyses are extended by exploring MRW simulations under three scenarios: (1) central place foraging, (2) behavioral adaptation to resource depletion (avoidance of latest visited locations) and (3) transition from MRW towards Levy walk by narrowing memory capacity to a trailing time window. A generalized statistical-mechanical theory with the power to model cognitive map influence on individual space use will be important for statistical analyses of animal habitat preferences and the mechanics behind site fidelity and home ranges. Copyright © 2011 Elsevier Ltd. All rights reserved.

Chemical and magnetic analyses on tree bark as an effective tool for biomonitoring: A case study in Lisbon (Portugal).

PubMed

Brignole, Daniele; Drava, Giuliana; Minganti, Vincenzo; Giordani, Paolo; Samson, Roeland; Vieira, Joana; Pinho, Pedro; Branquinho, Cristina

2018-03-01

Tree bark has proven to be a reliable tool for biomonitoring deposition of metals from the atmosphere. The aim of the present study was to test if bark magnetic properties can be used as a proxy of the overall metal loads of a tree bark, meaning that this approach can be used to discriminate different effects of pollution on different types of urban site. In this study, the concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, P, Pb, V and Zn were measured by ICP-OES in bark samples of Jacaranda mimosifolia, collected along roads and in urban green spaces in the city of Lisbon (Portugal). Magnetic analyses were also performed on the same bark samples, measuring Isothermal Remanent Magnetization (IRM), Saturation Isothermal Remanent Magnetization (SIRM) and Magnetic Susceptibility (χ). The results confirmed that magnetic analyses can be used as a proxy of the overall load of trace elements in tree bark, and could be used to distinguish different types of urban sites regarding atmospheric pollution. Together with trace element analyses, magnetic analyses could thus be used as a tool to provide high-resolution data on urban air quality and to follow up the success of mitigation actions aiming at decreasing the pollutant load in urban environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Historic global biomass burning emissions for CMIP6 (BB4CMIP) based on merging satellite observations with proxies and fire models (1750-2015)

NASA Astrophysics Data System (ADS)

van Marle, Margreet J. E.; Kloster, Silvia; Magi, Brian I.; Marlon, Jennifer R.; Daniau, Anne-Laure; Field, Robert D.; Arneth, Almut; Forrest, Matthew; Hantson, Stijn; Kehrwald, Natalie M.; Knorr, Wolfgang; Lasslop, Gitta; Li, Fang; Mangeon, Stéphane; Yue, Chao; Kaiser, Johannes W.; van der Werf, Guido R.

2017-09-01

Fires have influenced atmospheric composition and climate since the rise of vascular plants, and satellite data have shown the overall global extent of fires. Our knowledge of historic fire emissions has progressively improved over the past decades due mostly to the development of new proxies and the improvement of fire models. Currently, there is a suite of proxies including sedimentary charcoal records, measurements of fire-emitted trace gases and black carbon stored in ice and firn, and visibility observations. These proxies provide opportunities to extrapolate emission estimates back in time based on satellite data starting in 1997, but each proxy has strengths and weaknesses regarding, for example, the spatial and temporal extents over which they are representative. We developed a new historic biomass burning emissions dataset starting in 1750 that merges the satellite record with several existing proxies and uses the average of six models from the Fire Model Intercomparison Project (FireMIP) protocol to estimate emissions when the available proxies had limited coverage. According to our approach, global biomass burning emissions were relatively constant, with 10-year averages varying between 1.8 and 2.3 Pg C yr-1. Carbon emissions increased only slightly over the full time period and peaked during the 1990s after which they decreased gradually. There is substantial uncertainty in these estimates, and patterns varied depending on choices regarding data representation, especially on regional scales. The observed pattern in fire carbon emissions is for a large part driven by African fires, which accounted for 58 % of global fire carbon emissions. African fire emissions declined since about 1950 due to conversion of savanna to cropland, and this decrease is partially compensated for by increasing emissions in deforestation zones of South America and Asia. These global fire emission estimates are mostly suited for global analyses and will be used in the Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations.

Agreement Between Responses From Community-Dwelling Persons With Stroke and Their Proxies on the NIH Neurological Quality of Life (Neuro-QoL) Short Forms.

PubMed

Kozlowski, Allan J; Singh, Ritika; Victorson, David; Miskovic, Ana; Lai, Jin-Shei; Harvey, Richard L; Cella, David; Heinemann, Allen W

2015-11-01

To examine agreement between patient and proxy responses on the Quality of Life in Neurological Disorders (Neuro-QoL) instruments after stroke. Cross-sectional observational substudy of the longitudinal, multisite, multicondition Neuro-QoL validation study. In-person, interview-guided, patient-reported outcomes. Convenience sample of dyads (N=86) of community-dwelling persons with stroke and their proxy respondents. Not applicable. Dyads concurrently completed short forms of 8 or 9 items for the 13 Neuro-QoL adult domains using the patient-proxy perspective. Agreement was examined at the scale-level with difference scores, intraclass correlation coefficients (ICCs), effect size statistics, and Bland-Altman plots, and at the item-level with kappa coefficients. We found no mean differences between patients and proxies on the Applied Cognition-General Concerns, Depression, Satisfaction With Social Roles and Activities, Stigma, and Upper Extremity Function (Fine Motor, activities of daily living) short forms. Patients rated themselves more favorably on the Applied Cognition-Executive Function, Ability to Participate in Social Roles and Activities, Lower Extremity Function (Mobility), Positive Affect and Well-Being, Anxiety, Emotional and Behavioral Dyscontrol, and Fatigue short forms. The largest mean patient-proxy difference observed was 3 T-score points on the Lower Extremity Function (Mobility). ICCs ranged from .34 to .59. However, limits of agreement showed dyad differences exceeding ±20 T-score points, and item-level agreement ranged from not significant to weighted kappa=.34. Proxy responses on Neuro-QoL short forms can complement responses of moderate- to high-functioning community-dwelling persons with stroke and augment group-level analyses, but do not substitute for individual patient ratings. Validation is needed for other stroke populations. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Numerical Modelling of Speleothem and Dripwater Chemistry: Interpreting Coupled Trace Element and Isotope Proxies for Climate Reconstructions

NASA Astrophysics Data System (ADS)

Owen, R.; Day, C. C.; Henderson, G. M.

2016-12-01

Speleothem palaeoclimate records are widely used but are often difficult to interpret due to the geochemical complexity of the soil-karst-cave system. Commonly analysed proxies (e.g. δ18O, δ13C and Mg/Ca) may be affected by multiple processes along the water flow path from atmospheric moisture source through to the cave drip site. Controls on speleothem chemistry include rainfall and aerosol chemistry, bedrock chemistry, temperature, soil pCO2, the degree of open-system dissolution and prior calcite precipitation. Disentangling the effects of these controls is necessary to fully interpret speleothem palaeoclimate records. To quantify the effects of these processes, we have developed an isotope-enabled numerical model based on the geochemical modelling software PHREEQC. The model calculates dripwater chemistry and isotopes through equilibrium bedrock dissolution and subsequent iterative CO2 degassing and calcite precipitation. This approach allows forward modelling of dripwater and speleothem proxies, both chemical (e.g. Ca concentration, pH, Mg/Ca and Sr/Ca ratios) and isotopic (e.g. δ18O, δ13C, δ44Ca and radiocarbon content), in a unified framework. Potential applications of this model are varied and the model may be readily expanded to include new isotope systems or processes. Here we focus on calculated proxy co-variation due to changes in model parameters. Examples include: - The increase in Ca concentration, decrease in δ13C and increase in radiocarbon content as bedrock dissolution becomes more open-system. - Covariation between δ13C, δ44Ca and trace metal proxies (e.g. Mg/Ca) predicted by changing prior calcite precipitation. - The effect of temperature change on all proxies through the soil-karst-cave system. Separating the impact of soil and karst processes on geochemical proxies allows more quantitative reconstruction of the past environment, and greater understanding in modern cave monitoring studies.

Associations between Race and Dementia Status and the Quality of End-of-Life Care.

PubMed

Luth, Elizabeth A; Prigerson, Holly G

2018-04-05

Non-Hispanic black and dementia patients receive more invasive and futile treatment at end of life (EOL) relative to others. Little is known about the relationship between race/ethnicity, dementia, and EOL care quality. Identify the relationship between race/ethnicity, dementia, and proxy reporters' evaluation of EOL care quality in older adults. Latent class analysis (LCA) of national survey data. 1588 deceased Medicare beneficiaries age 65 and older from the National Health and Aging Trends Study (2011-2016). LCA identified three types of quality EOL care using nine measures of symptom management, quality of healthcare encounters, and dignified treatment. Race and dementia were primary predictors of EOL care quality type. Adjusted models controlled for decedent education, sex, marital status, age, number of illnesses, number of hospitalizations, self-rated health, place of death, hospice involvement, and proxy relationship to decedent and familiarity with care. Over 20% of proxies report that dying individuals experienced suboptimal EOL care quality, characterized by pain, sadness, poor communication, and inattention to personal care needs. In adjusted analyses, proxies for non-Hispanic black decedents were less likely to provide negative care assessments than proxies for non-Hispanic white decedents (adjusted odds ratio [AOR]: 0.58; 95% confidence interval [CI]: 0.40-0.86). Proxies for decedents with dementia were less likely to provide negative assessments than proxies for decedents without dementia (AOR: 0.70; 95% CI: 0.51-0.97). Efforts to improve EOL care quality are needed. More positive EOL care quality assessments for non-Hispanic Black and dementia decedents appear counterintuitive given research demonstrating that these groups of individuals are likely to have received suboptimal EOL care. Because caregiver expectations for care may differ by decedent race and dementia status, research is needed to explore the role of caregiver expectations for EOL care to explain these paradoxical findings.

The conceptualization and measurement of cognitive reserve using common proxy indicators: Testing some tenable reflective and formative models.

PubMed

Ikanga, Jean; Hill, Elizabeth M; MacDonald, Douglas A

2017-02-01

The examination of cognitive reserve (CR) literature reveals a lack of consensus regarding conceptualization and pervasive problems with its measurement. This study aimed at examining the conceptual nature of CR through the analysis of reflective and formative models using eight proxies commonly employed in the CR literature. We hypothesized that all CR proxies would significantly contribute to a one-factor reflective model and that educational and occupational attainment would produce the strongest loadings on a single CR factor. The sample consisted of 149 participants (82 male/67 female), with 18.1 average years of education and ages of 45-99 years. Participants were assessed for eight proxies of CR (parent socioeconomic status, intellectual functioning, level of education, health literacy, occupational prestige, life leisure activities, physical activities, and spiritual and religious activities). Primary statistical analyses consisted of confirmatory factor analysis (CFA) to test reflective models and structural equation modeling (SEM) to evaluate multiple indicators multiple causes (MIMIC) models. CFA did not produce compelling support for a unitary CR construct when using all eight of our CR proxy variables in a reflective model but fairly cogent evidence for a one-factor model with four variable proxies. A second three-factor reflective model based upon an exploratory principal components analysis of the eight proxies was tested using CFA. Though all eight indicators significantly loaded on their assigned factors, evidence in support of overall model fit was mixed. Based upon the results involving the three-factor reflective model, two alternative formative models were developed and evaluated. While some support was obtained for both, the model in which the formative influences were specified as latent variables appeared to best account for the contributions of all eight proxies to the CR construct. While the findings provide partial support for our hypothesis regarding CR as a one-dimensional reflective construct, the results strongly suggest that the construct is more complex than what can be captured in a reflective model alone. There is a need for theory to better identify and differentiate formative from reflective indicators and to articulate the mechanisms by which CR develops and operates.

Not so deserted…paleoecology and human subsistence in Central Iberia (Guadalajara, Spain) around the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Yravedra, José; Julien, Marie-Anne; Alcaraz-Castaño, Manuel; Estaca-Gómez, Verónica; Alcolea-González, Javier; de Balbín-Behrmann, Rodrigo; Lécuyer, Christophe; Marcel, Claude Hillaire; Burke, Ariane

2016-05-01

In contrast to the coastal areas of the Iberian Peninsula, the Upper Palaeolithic settlement of central Iberia, dominated by the Spanish plateau, is poorly known. Traditional models assume a total or virtual depopulation of the interior of the Iberian Peninsula during the Last Glacial. In this paper we present a detailed investigation of human-environment interactions through the first zooarchaeological, taphonomic and isotopic study of the key site of Peña Capón, a rock shelter located in the south-eastern foothills of the Central System range that contains a multi-layered deposit dated to marine isotope stage 2 (MIS 2). Analyses of the faunal assemblages of the Proto-Solutrean (3) and Middle Solutrean (2) layers show that human preferentially hunted horse, deer and iberian ibex living in the vicinity of the rock shelter. Isotope geochemistry of the animal remains of Peña Capón provides us with the first detailed intra-tooth multi-proxy analysis for this time period in south-western Europe, providing estimates of climatic conditions, seasonal flucturation of diet, as well as patterns of seasonal mobility. Our results indicate that human presence at Peña Capón was apparently restricted to relatively warm intervals around the LGM or reflects the presence of an ecological refuge, and provide us with evidence of recurrent human presence in the Iberian interior during the Upper Paleolithic prior to the Magdalenian.

Utilising a multi-item questionnaire to assess household food security in Australia.

PubMed

Butcher, Lucy M; O'Sullivan, Therese A; Ryan, Maria M; Lo, Johnny; Devine, Amanda

2018-03-15

Currently, two food sufficiency questions are utilised as a proxy measure of national food security status in Australia. These questions do not capture all dimensions of food security and have been attributed to underreporting of the problem. The purpose of this study was to investigate food security using the short form of the US Household Food Security Survey Module (HFSSM) within an Australian context; and explore the relationship between food security status and multiple socio-demographic variables. Two online surveys were completed by 2334 Australian participants from November 2014 to February 2015. Surveys contained the short form of the HFSSM and twelve socio-demographic questions. Cross-tabulations chi-square tests and a multinomial logistic regression model were employed to analyse the survey data. Food security status of the respondents was classified accordingly: High or Marginal (64%, n = 1495), Low (20%, n = 460) or Very Low (16%, n = 379). Significant independent predictors of food security were age (P < .001), marital status (P = .005), household income (P < .001) and education (P < .001). Findings suggest food insecurity is an important issue across Australia and that certain groups, regardless of income, are particularly vulnerable. Government policy and health promotion interventions that specifically target "at risk" groups may assist to more effectively address the problem. Additionally, the use of a multi-item measure is worth considering as a national indicator of food security in Australia. © 2018 Australian Health Promotion Association.

Testing the potential of bacterial branched tetraether membrane lipids as temperature proxy in peat and immature coal deposits

NASA Astrophysics Data System (ADS)

Weijers, J. W. H.; Steinmann, P.; Hopmans, E. C.; Basiliko, N.; Finkelstein, S. A.; Johnson, K. R.; Schouten, S.; Sinninghe Damsté, J. S.

2012-04-01

Branched glycerol dialkyl glycerol tetraether (brGDGT) membrane lipids occur ubiquitously in peat and soil. In soil, the degree of methylation and cyclisation of branched tetraethers (MBT index and CBT ratio, respectively) has shown to relate to both soil pH and annual mean air temperature (MAT). Using this relation, past annual MATs can be reconstructed by analysing brGDGTs in marine sediment records near large river outflows. More recently, the potential of this MBT/CBT proxy is also being explored in lakes. Despite being more abundant in peat than soils, however, the utility of the proxy has not yet been fully explored in peat records. Present day peat records generally extent back to the early Holocene, but if the MBT/CBT proxy were shown to be applicable in peat deposits, there is also potential to apply it to immature coal deposits like lignites, which could provide valuable snapshots of continental climate back to the early Cenozoic. Here results are presented of analyses of different peats in south eastern Canada, showing that the pH of peat along a nutrient gradient is rather well reflected by the CBT. Annual MAT reconstructions based on the MBT/CBT soil calibration, however, tend to overestimate measured MAT. This is also the case for peat analysed from the surface of Etang de la Gruère peat bog in the Swiss Jura Mountains. Along the 6m depth profile of this bog (~13ka), CBT-reconstructed pH is compared with in-situ measured pore water pH showing that the brGDGT composition does not reflect present-day in-situ conditions. Instead, it reflects a stratigraphic boundary between Carex and Sphagnum dominated peat at 4 m depth that is not present in the pore water profile, testifying to a 'fossil' nature of the brGDGTs down the peat bog. Analyses of three immature coals of the Argonne Premium Coal Series reveal that branched GDGTs are present in the most immature coal, the Beulah Zap lignite (Ro = 0.25%), and only just above detection limit in the Wyodak Anderson coal (Ro = 0.32%), both of about the same age (Late Palaeocene). In the more mature Illinois #6 coal (Ro = 0.46%), brGDGTs are completely absent. In the Denver Basin, a comparison is made between outcrop and drilled core samples of Palaeocene lignites. BrGDGTs are preserved in the core samples, although in low quantities compared to peat. Outcrop samples are clearly overprinted by modern soil derived brGDGTs, despite digging a meters deep trench, which shows the need to obtain fresh non-weathered samples by coring. Reconstructed annual MAT for both the Beulah Zap and the Denver Basin lignites are several degrees higher than estimates based on leaf margin and oxygen isotope analyses from the same sites. Both reconstructions do testify, nevertheless, to the warm continental conditions during the early Cenozoic of the central U.S.A.. Although further validation is required, potentially in the form of a specific peat calibration, these results do show potential for application of the MBT/CBT temperature proxy in peat and lignite deposits.

Strigeid parasites of Circus buffoni from Argentina, with the description of a new species of Parastrigea Szidat, 1928.

PubMed

Drago, Fabiana B; Núñez, Verónica; Lunaschi, Lía I

2018-03-01

Studying the Helminthological Collection of Museo de La Plata (MLP-He), several specimens of digeneans, recovered parasitizing a long-winged harrier, Circus buffoni (Accipitridae) from Buenos Aires Argentina, were analysed. The morphological and morphometric analysis of these specimens revealed the presence of two strigeid species, one of them new for science. Parastrigea buffoni n. sp. is characterised by a forebody differentiated in a retractile cephalic region with a large opening and a balloon-shaped collar region or collerette, suckers located in cephalic region, holdfast organ with well development dorsal and ventral lips that can emerge through opening, a claviform hindbody, a large copulatory bursa with muscular ring (Ringnapf) and a genital cone well delimited, crossed by a sinuous hermaphroditic duct with internal rugae. The euryxenous parasite, Strigea falconis brasiliana, is briefly described, parasitizing a new host. This is the first record of helminths parasitizing long-winged harrier.

Children With Anorectal Malformations, Hirschsprung Disease, and Their Siblings: Proxy Reports and Self-Reports.

PubMed

Hartman, Esther E; Oort, Frans J; Aronson, Daniel C; van der Steeg, Alida F W; Heij, Hugo A; van Heurn, Ernest; Madern, Gerard C; van der Zee, David C; de Blaauw, Ivo; van Dijk, A; Sprangers, Mirjam A G

2015-12-01

The aim of the present study was to compare parent proxy reports with that of self-reports of children with anorectal malformations (ARMs) or Hirschsprung disease (HD) and healthy siblings and thereafter was examine whether these comparisons differed between patients and their siblings. Parents (n = 98) of either children with ARM (n = 44) or HD (n = 54) and a healthy sibling (n = 98) recruited from the 6 Dutch pediatric surgical centers and from the ARM and HD patient societies were included in this cross-sectional multilevel study. Agreement between child self-reports and parent proxy reports was compared through mean differences and through (intraclass) correlations. We conducted multilevel analyses to take dependencies between assessments within families into account. All of the children (children with ARM or HD and their siblings) reported more pain and symptoms than their parents reported. We also found that only children with ARM or HD reported less positive emotions than their parents. Furthermore, higher correlations were found between parent proxy reports and patient-self reports than between parent proxy reports and sibling self-reports on cognitive functioning and social interaction. Parents tend to overestimate the physical functioning of both their ill and healthy children, and overestimate the emotional functioning of only their children with ARM or HD. Furthermore, children with ARM or HD and parents agree more on health-related quality of life domains than healthy children and parents.

Development of Proxies for Vent Fluid Trace Metal Concentrations and pH through Study of Sulfide Chimney Linings

NASA Astrophysics Data System (ADS)

Evans, G. N.; Tivey, M. K.; Seewald, J.; Rouxel, O. J.; Monteleone, B.

2016-12-01

Analyses of trace elements (Ag, As, Co, Mn, and Zn) hosted in the chalcopyrite linings of `black smoker' chimneys using secondary ion mass spectrometry (SIMS) have been combined with data for trace metal concentrations in corresponding vent fluids to investigate fluid-mineral partitioning of trace elements. Goals of this research include development of proxies for fluid chemistry based on mineral trace element content. The use of SIMS allows for the measurement of trace elements below the detection limits of electron microprobe and at the necessary spatial resolution (20 microns) to examine fine-grained and mixed-mineral samples. Results indicate that the chalcopyrite linings of many `black smoker' chimneys are homogeneous with respect to Ag, Mn, Co, and Zn. Minerals picked from samples exhibiting homogeneity with respect to specific elements were dissolved and analyzed by solution inductively coupled plasma mass spectrometry (ICP-MS) for use as working standards. Results also document a strong correlation between the Ag content of chalcopyrite and the Ag:Cu ratio of the corresponding hydrothermal fluid. This supports systematic partitioning of Ag into chalcopyrite as a substitute for Cu, providing a proxy for fluid Ag concentration. Additionally, the Ag content of chalcopyrite correlates with fluid pH, particularly at pH>3, and thus represents an effective proxy for fluid pH. Application of these proxies to chimney samples provides an opportunity to better identify hydrothermal conditions even when fluids have not been sampled, or not fully analyzed.

Identifying genes affectng stress response in rainbow trout

USDA-ARS?s Scientific Manuscript database

Genomic analyses have the potential to impact aquaculture production traits by identifying markers as proxies for traits which are expensive or difficult to measure and characterizing genetic variation and biochemical mechanisms underlying phenotypic variation. One such set of traits are the respon...

Measuring the sustainability of a natural system by using multi-criteria distance function methods: Some critical issues.

PubMed

Diaz-Balteiro, L; Belavenutti, P; Ezquerro, M; González-Pachón, J; Ribeiro Nobre, S; Romero, C

2018-05-15

There is an important body of literature using multi-criteria distance function methods for the aggregation of a battery of sustainability indicators in order to obtain a composite index. This index is considered to be a proxy of the sustainability goodness of a natural system. Although this approach has been profusely used in the literature, it is not exempt from difficulties and potential pitfalls. Thus, in this paper, a significant number of critical issues have been identified showing different procedures capable of avoiding, or at least of mitigating, the inherent potential pitfalls associated with each one. The recommendations made in the paper could increase the theoretical soundness of the multi-criteria distance function methods when this type of approach is applied in the sustainability field, thus increasing the accuracy and realism of the sustainability measurements obtained. Copyright © 2018 Elsevier Ltd. All rights reserved.

Calibrating multiple isotopic proxies in a modern aragonite speleothem from northeast India

NASA Astrophysics Data System (ADS)

Ronay, E.; Oster, J. L.; Sharp, W. D.; Marks, N.; Erhardt, A.; Breitenbach, S. F. M.

2017-12-01

Uranium, strontium, and calcium isotope ratios in calcite speleothems are used as proxies for water-soil-rock interactions and prior calcite precipitation, and thus provide information about effective rainfall amount variations, primarily in semi-arid or highly seasonal regions. However, less is known about how these proxies function in humid regions and in aragonite speleothems. In this study, we use meteorological data to calibrate (234U/238U)i and 87Sr/86Sr in a modern aragonite speleothem from northeast India, the rainiest place on Earth, to determine how these proxies reflect effective monsoon rainfall amount. MAW-0201 is an annually laminated aragonite stalagmite that grew from 1960-2013 in Mawmluh Cave, Meghalaya, India. Rainfall here is extremely seasonal due to the Indian Summer Monsoon (ISM), which brings several meters of rain to the region each summer, but with inter-annual variability in total rainfall. The δ18O in Mawmluh dripwater and speleothems reflects moisture source and transport, rather than rainfall amount. Variations in Mg, U, and Ba concentrations in MAW-0201 show seasonal and multi-annual variability. U and Mg are closely correlated, but multi-year periods show significant anti-correlation. The Mg and U distribution coefficients in calcite and aragonite indicate correlated periods are times of prior calcite precipitation (PCP) and anti-correlated periods are times of prior aragonite precipitation (PAP) in the epikarst. We use δ44/40Ca to test this hypothesis, as Ca isotopes fractionate differently during calcite and aragonite precipitation and speleothem δ44/40Ca will record unique PAP and PCP fingerprints. We propose such shifts from PCP to PAP reflect hydrologic variability and/or flow path changes, which provide a useful tool for understanding epikarst hydrology but may also be a complicating factor in speleothem-based paleoclimate interpretations. Preliminary (234U/238U)i (always <1) and 87Sr/86Sr spanning 1991-2009 each show significant variability outside of analytical error. (234U/238U)i displays a decadal trend, gradually increasing until 2000 and decreasing to the end of the record. Several years in the 87Sr/86Sr record have anomalously high values, which may reflect increased sea spray input and provide unique information on the wind component of the ISM.

Computing the Local Field Potential (LFP) from Integrate-and-Fire Network Models.

PubMed

Mazzoni, Alberto; Lindén, Henrik; Cuntz, Hermann; Lansner, Anders; Panzeri, Stefano; Einevoll, Gaute T

2015-12-01

Leaky integrate-and-fire (LIF) network models are commonly used to study how the spiking dynamics of neural networks changes with stimuli, tasks or dynamic network states. However, neurophysiological studies in vivo often rather measure the mass activity of neuronal microcircuits with the local field potential (LFP). Given that LFPs are generated by spatially separated currents across the neuronal membrane, they cannot be computed directly from quantities defined in models of point-like LIF neurons. Here, we explore the best approximation for predicting the LFP based on standard output from point-neuron LIF networks. To search for this best "LFP proxy", we compared LFP predictions from candidate proxies based on LIF network output (e.g, firing rates, membrane potentials, synaptic currents) with "ground-truth" LFP obtained when the LIF network synaptic input currents were injected into an analogous three-dimensional (3D) network model of multi-compartmental neurons with realistic morphology, spatial distributions of somata and synapses. We found that a specific fixed linear combination of the LIF synaptic currents provided an accurate LFP proxy, accounting for most of the variance of the LFP time course observed in the 3D network for all recording locations. This proxy performed well over a broad set of conditions, including substantial variations of the neuronal morphologies. Our results provide a simple formula for estimating the time course of the LFP from LIF network simulations in cases where a single pyramidal population dominates the LFP generation, and thereby facilitate quantitative comparison between computational models and experimental LFP recordings in vivo.

Detecting oscillatory patterns and time lags from proxy records with non-uniform sampling: Some pitfalls and possible solutions

NASA Astrophysics Data System (ADS)

Donner, Reik

2013-04-01

Time series analysis offers a rich toolbox for deciphering information from high-resolution geological and geomorphological archives and linking the thus obtained results to distinct climate and environmental processes. Specifically, on various time-scales from inter-annual to multi-millenial, underlying driving forces exhibit more or less periodic oscillations, the detection of which in proxy records often allows linking them to specific mechanisms by which the corresponding drivers may have affected the archive under study. A persistent problem in geomorphology is that available records do not present a clear signal of the variability of environmental conditions, but exhibit considerable uncertainties of both the measured proxy variables and the associated age model. Particularly, time-scale uncertainty as well as the heterogeneity of sampling in the time domain are source of severe conceptual problems that may lead to false conclusions about the presence or absence of oscillatory patterns and their mutual phasing in different archives. In my presentation, I will discuss how one can cope with non-uniformly sampled proxy records to detect and quantify oscillatory patterns in one or more data sets. For this purpose, correlation analysis is reformulated using kernel estimates which are found superior to classical estimators based on interpolation or Fourier transform techniques. In order to characterize non-stationary or noisy periodicities and their relative phasing between different records, an extension of continuous wavelet transform is utilized. The performance of both methods is illustrated for different case studies. An extension to explicitly considering time-scale uncertainties by means of Bayesian techniques is briefly outlined.

Holocene climate dynamics in the Eastern Italian Alps: a multi-proxy study from ice and peat bogs

NASA Astrophysics Data System (ADS)

Poto, Luisa; Gabrieli, Jacopo; Segnana, Michela; Festi, Daniela; Oeggl, Klaus; Barbante, Carlo

2014-05-01

The Eastern Italian Alps are located near one of the areas in the world with some of the longest records of extreme environmental use by human activity. In this area, paleo-climate studies are hampered by the lack of high-resolution multi-proxy records with adequate chronological control. With this project, we propose to reconstruct Holocene climatic and environmental variations in the Eastern Italian Alps using terrestrial and glaciological archives. We aim to study the characteristics of different climate stages in this sector of the Alps using an ice core drilled on the top of the Ortles glacier (46°30' N, 10°32 E, 3850 m a.s.l.) and ombrotrophic peat bog records from the Dolomites (Danta di Cadore, 46°34' N, 12°33 E, 1400 m a.s.l. and Coltrondo 46°39'28.37''N 12°26'59.17''E, 1800 m a.s.l., Belluno province). The study of global climatic change require a holistic and multi-proxy approach to better understand several complex and often non-linear relationships. In the Italian Alps our study on peat cores represents the first attempt where a multi-proxy approach is applied, and here we report our first results. A 7.0 m peat sequence was extracted in Danta di Cadore. The depth-age scale, based upon independent 14C and 210Pb dates and modeled with the Clam method (Blaauw, 2010), demonstrates that the archive covers more than 13,200 years (cal BP). We determined physical proprieties, Ca and Ti trends, pore water pH, conductivity, and Ca/Mg ratios to identify changes in trophic conditions. The results confirm that the uppermost 400 cm are composed of ombrotrophic peat representing the longest Eastern Alpine ombrotrophic record yet obtained, covering the last 7,000 years. The oldest radiocarbon age (13,200 years cal BP) provides evidence that, during the Bölling-Alleröd interstadial, the upper part of the Piave Glacier was ice-free up to 1400 m a.s.l.. At that time pollen assemblages show that a conifer forest characterized the local vegetation. This forest was then affected by the climatic cooling of the Younger Dryas, which caused an opening of the vegetation. The climatic amelioration occurring at the onset of the Holocene favored the local expansion of warmth-demanding species. X-ray Fluorescence Core Scanner (XRF-CS) analysis was applied for the first time on Eastern Alpine peat sequences. XRF-CS signals were calibrated with ICP-MS, showing very high correlation and demonstrating that the XRF-CS technique provides reliable quantitative data. Results provide information about geochemical processes occurring in the bog. The impact of mining activity was also evaluated. Concentration levels and enrichment factors (EFs) of several trace elements such as Pb, Ag and Cd correspond to the historical data about mining activities in the Cadore region. Lead isotopes ratios were measured to identify natural and anthropogenic sources of Pb emissions. Results show an increase of Pb deriving from fuel combustion over the last decades that gradually overlie the impacts of mining activity. The decreasing 206Pb/207Pb trend reached its minimum value of 1.153 in the 1990s and then increased again. In these years, Italy started to follow EU rules to limit global pollutants in the atmosphere, and finally banned leaded fuels in 2002. Both 206Pb/207Pb ratio and Pb fluxes show a particular event between 1975 and 1980: this behavior is characteristic of the ILE (Isotopic Lead Experiment), a large-scale isotopic tracer experiment which was carried out in the Piedmont region (N-W Italy). This multi-proxy approach that integrates, using new chronological insights, chemical physical and biological features of the core, improves our understanding of Eastern Alpine Holocene climate, helping to delineate biotic and abiotic responses to climate dynamics during the present interglacial. Blaauw, M. 2010. Methods and code for 'classical' age modeling of radiocarbon sequences. Quarternary Geochronology, 5: 512-518.

Parent-child discrepancy in the assessment of health- related quality of life using the EQ-5D-Y questionnaire.

PubMed

Perez Sousa, Miguel Á; Olivares Sánchez-Toledo, Pedro R; Gusi Fuerte, Narcis

2017-12-01

The assessment of health-related quality of life (HRQoL) serves to detect changes over time in patients' health status and allows to do a cost-effectiveness analysis of treatments. When children with special health features cannot perform a self-assessment, it is possible to assess their HRQoL through their parents or caregivers. To date, the discrepancy in the assessment of HRQoL using the EQ-5D-Y questionnaire among children with cerebral palsy (CP) and their parents has not been analyzed. The objective of this study was to analyze the level of agreement in the HRQoL assessment using the EQ-5D-Y questionnaire and its proxy version among children with CP and their parents or caregivers. Children and adolescents with CP, and their parents, from a special education school in the region of Extremadura (Spain) participated in the study. The EQ-5D-Y questionnaire was used for children and the EQ-5D-Y proxy version, for parents. Interviews were conducted in the first quarter of 2015. The level of agreement in the responses was analyzed using the Cohen's kappa coefficient for the five domains of the EQ-5D-Y and the intraclass correlation coefficient for the visual analogue scale. Sixty-two children with CP and mild and/or moderate functional capacity impairment, and their parents, participated in the study. The level of agreement was poor in the HRQoL assessment between children and parents in all the questionnaire domains ( <0.20) and fair or poor ( <0.60) in the visual analogue scale. A high level of parent-child disagreement was observed in the HRQoL assessment in the population with CP using the EQ-5D-Y questionnaire. Sociedad Argentina de Pediatría

Tracing Altiplano-Puna plateau surface uplift via radiogenic isotope composition of Andean arc lavas

NASA Astrophysics Data System (ADS)

Scott, E. M.; Allen, M. B.; Macpherson, C.; McCaffrey, K. J. W.; Davidson, J.; Saville, C.

2016-12-01

We have compiled published geochemical data for Jurassic to Holocene Andean arc lavas from 5oN to 47oS, covering the current extent of the northern, central and southern volcanic zones. Using this dataset we evaluate the spatial and temporal evolution of age corrected Sr- and Nd-radiogenic isotopes in arc lavas at a continental-scale, in order to understand the tectonic and surface uplift histories of the Andean margin. It has long been noted that baseline 87Sr/86Sr and 143Nd/144Nd ratios of Quaternary lavas from the central volcanic zone, located within the Altiplano-Puna plateau, are distinct from volcanic rocks to the north and south. This is commonly attributed to greater crustal thickness, which increases to roughly twice that of the average continental crust within the Altiplano-Puna plateau. By comparing 87Sr/86Sr and 143Nd/144Nd ratios in Quaternary lavas to published crustal thickness models, present day topography and the compositions of basement terranes, we note that Sr- and Nd-isotope values of Quaternary lavas are an effective proxy for present day regional elevation. In contrast, variation in basement terranes has only a small, second order effect on isotopic composition at the scale of our study. Using this isotopic proxy, we infer the spatial extent of the plateau and its surface uplift history from the Jurassic to the present. Our results concur with a crustal thickening model of continued surface uplift, which initiated in the Altiplano, with deformation propagating southwards into the Puna throughout the Neogene and then continuing in central Chile and Argentina up to the present day.

Social monogamy in wild owl monkeys (Aotus azarae) of Argentina: the potential influences of resource distribution and ranging patterns

PubMed Central

Fernandez-Duque, Eduardo

2017-01-01

Using published and new data from a population of monogamous owl monkeys in the Argentinean Chaco, I examine the hypothesis that social monogamy is a default social system imposed upon males because the spatial and/or temporal distribution of resources and females makes it difficult for a single male to defend access to more than one mate. First, I examine a set of predictions on ranging patterns, use of space, and population density. This first section is followed by a second one considering predictions related to the abundance and distribution of food. Finally, I conclude with a section attempting to link the ranging and ecological data to demographic and life-history parameters as proxies for reproductive success. In support of the hypothesis, owl monkey species do live at densities (7 to 64 ind/km2) that are predicted for monogamous species, but groups occupy home ranges and core areas that vary substantially in size, with pronounced overlap of home ranges, but not of core areas. There are strong indications that the availability of food sources in the core areas during the dry season may be of substantial importance for regulating social monogamy in owl monkeys. Finally, none of the proxies for the success of groups were strongly related to the size of the home range or core area. The results I present do not support conclusively any single explanation for the evolution of social monogamy in owl monkeys, but they help us to better understand how it may function. Moreover, the absence of conclusive answers linking ranging, ecology, and reproductive success with the evolution of social monogamy in primates, offer renewed motivation for continuing to explore the evolution of monogamy in owl monkeys. PMID:25931263

Social monogamy in wild owl monkeys (Aotus azarae) of Argentina: the potential influences of resource distribution and ranging patterns.

PubMed

Fernandez-Duque, Eduardo

2016-03-01

Using published and new data from a population of monogamous owl monkeys in the Argentinean Chaco, I examine the hypothesis that social monogamy is a default social system imposed upon males because the spatial and/or temporal distribution of resources and females makes it difficult for a single male to defend access to more than one mate. First, I examine a set of predictions on ranging patterns, use of space, and population density. This first section is followed by a second one considering predictions related to the abundance and distribution of food. Finally, I conclude with a section attempting to link the ranging and ecological data to demographic and life-history parameters as proxies for reproductive success. In support of the hypothesis, owl monkey species do live at densities (7-64 ind/km(2) ) that are predicted for monogamous species, but groups occupy home ranges and core areas that vary substantially in size, with pronounced overlap of home ranges, but not of core areas. There are strong indications that the availability of food sources in the core areas during the dry season may be of substantial importance for regulating social monogamy in owl monkeys. Finally, none of the proxies for the success of groups were strongly related to the size of the home range or core area. The results I present do not support conclusively any single explanation for the evolution of social monogamy in owl monkeys, but they help us to better understand how it may function. Moreover, the absence of conclusive answers linking ranging, ecology, and reproductive success with the evolution of social monogamy in primates, offer renewed motivation for continuing to explore the evolution of monogamy in owl monkeys. © 2015 Wiley Periodicals, Inc.

Using linked educational attainment data to reduce bias due to missing outcome data in estimates of the association between the duration of breastfeeding and IQ at 15 years.

PubMed

Cornish, Rosie P; Tilling, Kate; Boyd, Andy; Davies, Amy; Macleod, John

2015-06-01

Most epidemiological studies have missing information, leading to reduced power and potential bias. Estimates of exposure-outcome associations will generally be biased if the outcome variable is missing not at random (MNAR). Linkage to administrative data containing a proxy for the missing study outcome allows assessment of whether this outcome is MNAR and the evaluation of bias. We examined this in relation to the association between infant breastfeeding and IQ at 15 years, where a proxy for IQ was available through linkage to school attainment data. Subjects were those who enrolled in the Avon Longitudinal Study of Parents and Children in 1990-91 (n = 13 795), of whom 5023 had IQ measured at age 15. For those with missing IQ, 7030 (79%) had information on educational attainment at age 16 obtained through linkage to the National Pupil Database. The association between duration of breastfeeding and IQ was estimated using a complete case analysis, multiple imputation and inverse probability-of-missingness weighting; these estimates were then compared with those derived from analyses informed by the linkage. IQ at 15 was MNAR-individuals with higher attainment were less likely to have missing IQ data, even after adjusting for socio-demographic factors. All the approaches underestimated the association between breastfeeding and IQ compared with analyses informed by linkage. Linkage to administrative data containing a proxy for the outcome variable allows the MNAR assumption to be tested and more efficient analyses to be performed. Under certain circumstances, this may produce unbiased results. © The Author 2015. Published by Oxford University Press on behalf of the International Epidemiological Association.

Arsenic concentration in water and bovine milk in Cordoba, Argentina. Preliminary results.

PubMed

Pérez-Carrera, Alejo; Fernández-Cirelli, Alicia

2005-02-01

The Chaco Pampean Plain of central Argentina constitutes one of the largest regions of high arsenic (As) groundwaters known, covering around 1 x 10(6) km2 (Smedley & Kinniburg, 2002; Farías et al. 2004). The high-As groundwaters are from Quaternary deposits of loess (mainly silt) with intermixed rhyolitic or dacitic volcanic ash (Nicolli et al. 1989, Smedley et al. 1998,2002). Early in the last century an endemic disease due to contamination of drinking water with arsenic was recognised. This disease is called HACRE (Hidroarsenicismo Crónico Regional Endémico, Chronic Endemic Regional Hydroarsenism) and is connected with a particular type of skin cancer (Astolfi et al. 1981). One of the most affected region is the province of Cordoba, where Nicolli et al. (1989) reported As concentrations that exceed the maximun level permitted for drinking water of 50 microg/l for 82% of the groundwater samples (n=60) of a study area comprising approximately 10000 km2. The southeast of Cordoba is an important milk production zone in Argentina, where dairy product consumption is up to 192 equivalent milk l/inhabitant/year. As a secretion of the mammary gland, milk can carry numerous xenobiotic substances, which constitute a technological risk factor for dairy products and above all for the health of the consumer (Licata et al. 2004). Nevertheless no studies on the incidence of high-As livestock drinking water in livestock health and its transfer to milk have been performed in Argentina. The aim of the present study was the determination of arsenic content in livestock drinking water and milk from dairy farms located in an area of high-As groundwaters, to analyse the relation between As uptake through water and its transfer to milk.

The Barrancas anticline in west-central Argentina: new geomorphic and geologic constraints on the geometry and activity of a fault-related fold

NASA Astrophysics Data System (ADS)

Rimando, J. M.; Schoenbohm, L. M.

2016-12-01

The Barrancas anticline in Mendoza Province, west-central Argentina is a N-NW-oriented, east-vergent fault-bend fold located in the transition from the mainly east-vergent, thin-skinned Argentine Precordillera to the mainly west-vergent, thick-skinned Sierras Pampeanas — one of the most active thrust zones on Earth. Previous studies of the Barrancas anticline interpreted its structure from 2-D and 3-D seismic data. The anticline is a fault-bend fold with multiple segments with different uplift histories and which linked only after 2.3Ma. This study aims to establish the temporal persistence of segmentation and to describe the role, extent and rates of deformation processes involved in the development of the Barrancas anticline from morphometric analyses, geologic and geomorphic mapping, and accurate dating of relevant geomorphic features. Longitudinal profile analysis of streams on the anticline reveals marked differences in normalized steepness index (ksn) between the western and eastern limbs as well as variation along strike. This distribution of ksn values reveals patterns consistent with asymmetry and segmentation of the Barrancas anticline. Swath profiles parallel to the fold axis resemble fault slip distribution profiles which was a basis for segmentation from previous studies. Drainage basin morphometric indices such as hypsometry, drainage density, and basin elongation were also measured. Hypsometric integral values were particularly higher on the west than on the east, possibly indicating younger folding on the western limb. This study will contribute to a better understanding of the nature, extent, timing, and rate of folding at the transition from thin- to thick-skinned thrust deformation in west-central Argentina. Additionally, this study will contribute to assessment of seismic hazards associated with fault-related folds in Argentina and in similar tectonic settings worldwide.

The PRISM (Pliocene Palaeoclimate) reconstruction: Time for a paradigm shift

USGS Publications Warehouse

Dowsett, Harry J.; Robinson, Marci M.; Stoll, Danielle K.; Foley, Kevin M.; Johnson, Andrew L. A.; Williams, Mark; Riesselman, Christina

2013-01-01

Global palaeoclimate reconstructions have been invaluable to our understanding of the causes and effects of climate change, but single-temperature representations of the oceanic mixed layer for data–model comparisons are outdated, and the time for a paradigm shift in marine palaeoclimate reconstruction is overdue. The new paradigm in marine palaeoclimate reconstruction stems the loss of valuable climate information and instead presents a holistic and nuanced interpretation of multi-dimensional oceanographic processes and responses. A wealth of environmental information is hidden within the US Geological Survey's Pliocene Research,Interpretation and Synoptic Mapping (PRISM) marine palaeoclimate reconstruction, and we introduce here a plan to incorporate all valuable climate data into the next generation of PRISM products. Beyond the global approach and focus, we plan to incorporate regional climate dynamics with emphasis on processes, integrating multiple environmental proxies wherever available in order to better characterize the mixed layer, and developing a finer time slice within the Mid-Piacenzian Age of the Pliocene, complemented by underused proxies that offer snapshots into environmental conditions. The result will be a proxy-rich, temporally nested, process-oriented approach in a digital format - a relational database with geographic information system capabilities comprising a three-dimensional grid representing the surface layer, with a plethora of data in each cell.

Immediate replacement of fishing with dairying by the earliest farmers of the northeast Atlantic archipelagos

PubMed Central

Cramp, Lucy J. E.; Jones, Jennifer; Sheridan, Alison; Smyth, Jessica; Whelton, Helen; Mulville, Jacqui; Sharples, Niall; Evershed, Richard P.

2014-01-01

The appearance of farming, from its inception in the Near East around 12 000 years ago, finally reached the northwestern extremes of Europe by the fourth millennium BC or shortly thereafter. Various models have been invoked to explain the Neolithization of northern Europe; however, resolving these different scenarios has proved problematic due to poor faunal preservation and the lack of specificity achievable for commonly applied proxies. Here, we present new multi-proxy evidence, which qualitatively and quantitatively maps subsistence change in the northeast Atlantic archipelagos from the Late Mesolithic into the Neolithic and beyond. A model involving significant retention of hunter–gatherer–fisher influences was tested against one of the dominant adoptions of farming using a novel suite of lipid biomarkers, including dihydroxy fatty acids, ω-(o-alkylphenyl)alkanoic acids and stable carbon isotope signatures of individual fatty acids preserved in cooking vessels. These new findings, together with archaeozoological and human skeletal collagen bulk stable carbon isotope proxies, unequivocally confirm rejection of marine resources by early farmers coinciding with the adoption of intensive dairy farming. This pattern of Neolithization contrasts markedly to that occurring contemporaneously in the Baltic, suggesting that geographically distinct ecological and cultural influences dictated the evolution of subsistence practices at this critical phase of European prehistory. PMID:24523264

Environment and paleoecology of a 12 ka mid-North American Younger Dryas forest chronicled in tree rings

USGS Publications Warehouse

Panyushkina, Irina P.; Leavitt, Steven W.; Thompson, Todd A.; Schneider, Allan F.; Lange, Todd

2008-01-01

Until now, availability of wood from the Younger Dryas abrupt cooling event (YDE) in N. America ca. 12.9 to 11.6 ka has been insufficient to develop high-resolution chronologies for refining our understanding of YDE conditions. Here we present a multi-proxy tree-ring chronology (ring widths, “events” evidenced by microanatomy and macro features, stable isotopes) from a buried black spruce forest in the Great Lakes area (Liverpool East site), spanning 116 yr at ca. 12,000 cal yr BP. During this largely cold and wet period, the proxies convey a coherent and precise forest history including frost events, tilting, drowning and burial in estuarine sands as the Laurentide Ice Sheet deteriorated. In the middle of the period, a short mild interval appears to have launched the final and largest episode of tree recruitment. Ultimately the tops of the trees were sheared off after death, perhaps by wind-driven ice floes, culminating an interval of rising water and sediment deposition around the base of the trees. Although relative influences of the continental ice sheet and local effects from ancestral Lake Michigan are indeterminate, the tree-ring proxies provide important insight into environment and ecology of a N. American YDE boreal forest stand.

Climate and tectonic variability during Late Quaternary in western fringe of Tibetan Plateau: case study from Trans-Himalayan ranges of Ladakh, NW India

NASA Astrophysics Data System (ADS)

Phartiyal, B.

2016-12-01

The climate system plays an important role in the geomorphological dynamics of a region. The cold, arid, high altitude, tectonically active areas of Ladakh (India) in Trans Himalaya, western Tibetan Plateau is none exception. Noticeable change in the landscape with a shift from fluvial to lacustrine regime at 10000 yrs BP forming big open valley lakes occupying the present day river valleys is attributed to the early Holocene northward advancement of the mean latitudinal position of the summer ITCZ causing wetter conditions in this dry area. The glaciers of the Ladakh range are almost depleted and the northern range glaciers show andrastic retreat in the Quaternary time. Lakes were studied using multi-proxies, to record centennial and decadal scale climatic variability. Spatial and temporal setting of Spituk palaeolake (12600-240 cal yrs BP) along Indus River, was analyzed using multi proxies. The lake that extended for 40-50 km covering an area of 106 km2, was formed after Older Dryas as a result of river blockage by precipitation induced debris flow and seismicity. Two lake phases between 12600-9000 and 5500-3200 cal yrs BP show stable lake conditions and have synchronous relationship between high variation in monsoon intensity, high δ18O values in the Guliya core, rise in temperature and high solar insolation. High magnetic susceptibility and clay content along with diversified diatom and other freshwater algae and land derived organic matter are indicative of fresh water supply leading to high lake level from 4700 yr BP onwards in the present pro-glacial lakes studied. The multi-proxy data provides evidence of much higher and stable lake level during 3700 yr BP and 3000 yr BP onwards due to high water supply in these lake. It is in contrast to the records of weak ISM conditions and low lake level in rest of the part of Indian peninsula during the period. The study also suggests strong western disturbance activity during 4800-3000 yr BP leading to high lake level in this region. The ongoing researches aim to make an inventory/dataset of these records and address the climate-tectonics interaction with respect to the lake outburst consequences.

Planktonic Foraminifera Proxies Calibration Off the NW Iberian Margin: Nutrients Approach

NASA Astrophysics Data System (ADS)

Salgueiro, E.; Castro, C. G.; Zuniga, D.; Martin, P. A.; Groeneveld, J.; de la Granda, F.; Villaceiros-Robineau, N.; Alonso-Perez, F.; Alberto, A.; Rodrigues, T.; Rufino, M. M.; Abrantes, F. F. G.; Voelker, A. H. L.

2014-12-01

Planktonic foraminifera (PF) shells preserved in marine sediments are a useful tool to reconstruct productivity conditions at different geological timescales. However, the accuracy of these paleoreconstructions depends on the data set and calibration quality. Several calibration works have been defining and improving the use of proxies for productivity and nutrient cycling parameters. Our contribution is centred on a multi-proxy calibration at a regional coastal upwelling system. To minimize the existing uncertainties affecting the use of trace elements and C stable isotopes as productivity proxy in the high productivity upwelling areas, we investigate the content and distribution of Ba/Ca and δ13C in the water column, its transference into the planktonic foraminifera shells, and, how the living planktonic foraminifera Ba/Ca and δ13C signal is related to the same planktonic foraminiferal species preserved in the sediment record. This study is based on a large data set from two stations (RAIA - 75m water depth, and CALIBERIA - 350m water depth) located off the NW Iberian margin (41.5-42.5ºN; 9-10ºW), and includes: i) two year monthly water column data (temperature, salinity, nutrients, chlorophyll a, Ba/Ca, and δ13C-DIC); ii) seasonal Ba/Ca, δ13C in several living PF species at both stations; and iii) Ba/Ca and δ13C in several PF species from a large set of core-top sediment samples in the study region. Additionally, total organic carbon and total alkenones were also measured in the sediment. Our results showed the link between productivity proxies in the surface sediment foraminifera assemblage and the processes regulating the actual phytoplankton dynamics in an upwelling area. The understanding of this relationship has special relevance since it gives fundamental information related to the past oceanic biogeochemistry and/or climate and improves the prevision of future changes against possible climate variability due to anthropogenic forcing.

Hydrological and associated biogeochemical consequences of rapid global warming during the Paleocene-Eocene Thermal Maximum

NASA Astrophysics Data System (ADS)

Carmichael, Matthew J.; Inglis, Gordon N.; Badger, Marcus P. S.; Naafs, B. David A.; Behrooz, Leila; Remmelzwaal, Serginio; Monteiro, Fanny M.; Rohrssen, Megan; Farnsworth, Alexander; Buss, Heather L.; Dickson, Alexander J.; Valdes, Paul J.; Lunt, Daniel J.; Pancost, Richard D.

2017-10-01

The Paleocene-Eocene Thermal Maximum (PETM) hyperthermal, 56 million years ago (Ma), is the most dramatic example of abrupt Cenozoic global warming. During the PETM surface temperatures increased between 5 and 9 °C and the onset likely took < 20 kyr. The PETM provides a case study of the impacts of rapid global warming on the Earth system, including both hydrological and associated biogeochemical feedbacks, and proxy data from the PETM can provide constraints on changes in warm climate hydrology simulated by general circulation models (GCMs). In this paper, we provide a critical review of biological and geochemical signatures interpreted as direct or indirect indicators of hydrological change at the PETM, explore the importance of adopting multi-proxy approaches, and present a preliminary model-data comparison. Hydrological records complement those of temperature and indicate that the climatic response at the PETM was complex, with significant regional and temporal variability. This is further illustrated by the biogeochemical consequences of inferred changes in hydrology and, in fact, changes in precipitation and the biogeochemical consequences are often conflated in geochemical signatures. There is also strong evidence in many regions for changes in the episodic and/or intra-annual distribution of precipitation that has not widely been considered when comparing proxy data to GCM output. Crucially, GCM simulations indicate that the response of the hydrological cycle to the PETM was heterogeneous - some regions are associated with increased precipitation - evaporation (P - E), whilst others are characterised by a decrease. Interestingly, the majority of proxy data come from the regions where GCMs predict an increase in PETM precipitation. We propose that comparison of hydrological proxies to GCM output can be an important test of model skill, but this will be enhanced by further data from regions of model-simulated aridity and simulation of extreme precipitation events.

Comparison of multi-proxy data with past1000 model output over the Terminal Classic Period (800-1000 A.D.) on the Yucatan Peninsula.

NASA Astrophysics Data System (ADS)

Van Pelt, S.; Kohfeld, K. E.; Allen, D. M.

2015-12-01

The decline of the Mayan Civilization is thought to be caused by a series of droughts that affected the Yucatan Peninsula during the Terminal Classic Period (T.C.P.) 800-1000 AD. The goals of this study are two-fold: (a) to compare paleo-model simulations of the past 1000 years with a compilation of multiple proxies of changes in moisture conditions for the Yucatan Peninsula during the T.C.P. and (b) to use this comparison to inform the modeling of groundwater recharge in this region, with a focus on generating the daily climate data series needed as input to a groundwater recharge model. To achieve the first objective, we compiled a dataset of 5 proxies from seven locations across the Yucatan Peninsula, to be compared with temperature and precipitation output from the Community Climate System Model Version 4 (CCSM4), which is part of the Coupled Model Intercomparison Project Phase 5 (CMIP5) past1000 experiment. The proxy dataset includes oxygen isotopes from speleothems and gastropod/ostrocod shells (11 records); and sediment density, mineralogy, and magnetic susceptibility records from lake sediment cores (3 records). The proxy dataset is supplemented by a compilation of reconstructed temperatures using pollen and tree ring records for North America (archived in the PAGES2k global network data). Our preliminary analysis suggests that many of these datasets show evidence of drier and warmer climate on the Yucatan Peninsula around the T.C.P. when compared to modern conditions, although the amplitude and timing of individual warming and drying events varies between sites. This comparison with modeled output will ultimately be used to inform backward shift factors that will be input to a stochastic weather generator. These shift factors will be based on monthly changes in temperature and precipitation and applied to a modern daily climate time series for the Yucatan Peninsula to produce a daily climate time series for the T.C.P.

Oral health-related quality of life in youth receiving cleft-related surgery: self-report and proxy ratings.

PubMed

Broder, Hillary L; Wilson-Genderson, Maureen; Sischo, Lacey

2017-04-01

This paper evaluated the impact of cleft-related surgery on the oral health-related quality of life (OHRQoL) of youth with cleft over time. Data were derived from a 5-year, multi-center, prospective, longitudinal study of 1196 youth with cleft lip and/or palate and their caregivers. Eligible youth were between 7.5 and 18.5 years old, spoke English or Spanish, and were non-syndromic. During each observational period, which included baseline, and 1- and 2-year post-baseline follow-up visits, youths and their caregivers completed the Child Oral Health Impact Profile, a validated measure of OHRQoL. Multilevel mixed-effects models were used to analyze the effects of receipt of craniofacial surgery on OHRQoL over time. During the course of this study a total of 516 patients (43 %) received at least one surgery. Youth in the surgery recommendation group had lower self- (β = -2.18, p < 0.05) and proxy-rated (β = -2.92, p < 0.02) OHRQoL when compared to non-surgical self- and proxy-rated OHRQoL at baseline. Both surgical and non-surgical youth (β = 3.73, p < 0.001) and caregiver (β = 1.91, p < 0.05) ratings of OHRQoL improved over time. There was significant incremental improvement (time × surgery interaction) in self-reported OHRQoL for youth postsurgery (β = 1.04, p < 0.05), but this postsurgery increment was not seen in the caregiver proxy ratings. Surgical intervention impacts OHRQoL among youth with cleft. Youth who were surgical candidates had lower baseline self- and caregiver-rated OHRQoL when compared to non-surgical youth. Youth who underwent cleft-related surgery had significant incremental improvements in self-rated but not caregiver (proxy)-rated OHRQoL after surgery.

Further analyses of Rio Cuarto impact glass

NASA Technical Reports Server (NTRS)

Schultz, Peter H.; Bunch, T. E.; Koeberl, C.; Collins, W.

1993-01-01

Initial analyses of the geologic setting, petrology, and geochemistry of glasses recovered from within and around the elongate Rio Cuarto (RC) craters in Argentina focused on selected samples in order to document the general similarity with impactites around other terrestrial impact craters and to establish their origin. Continued analysis has surveyed the diversity in compositions for a range of samples, examined further evidence for temperature and pressure history, and compared the results with experimentally fused loess from oblique hypervelocity impacts. These new results not only firmly establish their impact origin but provide new insight on the impact process.

Multi-Wheat-Model Ensemble Responses to Interannual Climate Variability

NASA Technical Reports Server (NTRS)

Ruane, Alex C.; Hudson, Nicholas I.; Asseng, Senthold; Camarrano, Davide; Ewert, Frank; Martre, Pierre; Boote, Kenneth J.; Thorburn, Peter J.; Aggarwal, Pramod K.; Angulo, Carlos

2016-01-01

We compare 27 wheat models' yield responses to interannual climate variability, analyzed at locations in Argentina, Australia, India, and The Netherlands as part of the Agricultural Model Intercomparison and Improvement Project (AgMIP) Wheat Pilot. Each model simulated 1981e2010 grain yield, and we evaluate results against the interannual variability of growing season temperature, precipitation, and solar radiation. The amount of information used for calibration has only a minor effect on most models' climate response, and even small multi-model ensembles prove beneficial. Wheat model clusters reveal common characteristics of yield response to climate; however models rarely share the same cluster at all four sites indicating substantial independence. Only a weak relationship (R2 0.24) was found between the models' sensitivities to interannual temperature variability and their response to long-termwarming, suggesting that additional processes differentiate climate change impacts from observed climate variability analogs and motivating continuing analysis and model development efforts.

Phanerozoic pCO2 recorded by the plants that used it: refinement, independent validation and multi-proxy comparison of a physiological model.

NASA Astrophysics Data System (ADS)

Franks, P.; Royer, D. L.; Kowalczyk, J.; Milligan, J.

2016-12-01

CO2 has been described as the most important greenhouse gas in terms of maintaining a habitable climate on Earth. However, pCO2 has not been constant through time and the resulting variability of its forcing has contributed to periodic swings in global climate between warmer and cooler periods. Reliable prediction of the magnitude and effects of future global warming with increasing pCO2 depends on quantifying climate sensitivity to forcing by pCO2, which can only be measured from the record of pCO2 and temperature in Earth's geological past. This has been difficult because of inherent uncertainties, sometimes unquantifiable, in the reconstruction of pCO2 for past geologic periods. Recently a new CO2 proxy was developed based on the principle that photosynthesis by plants is quantitatively dependent on pCO2 (CO2 being the substrate for photosynthesis), with the record of this relationship preserved in the structure and chemistry of plant fossils (Franks et al., 2014, Geophysical Research Letters, 41: 4685-4694). This method has constrained uncertainty to more moderate bounds and eliminated instances of unbounded uncertainty. Here we describe a refinement to one of the input physiological quantities, the present-day ratio of intercellular to ambient CO2 concentration, ci/ca, which improves model accuracy. We also summarise the key findings of an independent validation and multi proxy comparison of the model using fossil plant material from a floristically diverse early Paleocene site which, at 64.5 Ma, was living 1.5 m.y after the Cretaceous-Paleogene boundary (KPB) mass extinction event. Principal amongst these findings is an upward revision of pCO2 to a median 612 ppm for the early Paleocene, with a corresponding minimum average Earth system sensitivity of 3.8 °C.

New neotropical species of Trupanea (Diptera: Tephritidae) with unusual wing patterns

USDA-ARS?s Scientific Manuscript database

Four species of Trupanea (Diptera: Tephritidae) with unusual wing patterns are described from the Neotropical Region: T. dimorphica (Argentina), T. fasciata (Argentina), T. polita (Argentina and Bolivia), and T. trivittata (Argentina). Celidosphenella Hendel, 1914 and Melanotrypana Hering, 1944 are ...

Multi-centennial upper-ocean heat content reconstruction using online data assimilation

NASA Astrophysics Data System (ADS)

Perkins, W. A.; Hakim, G. J.

2017-12-01

The Last Millennium Reanalysis (LMR) provides an advanced paleoclimate ensemble data assimilation framework for multi-variate climate field reconstructions over the Common Era. Although reconstructions in this framework with full Earth system models remain prohibitively expensive, recent work has shown improved ensemble reconstruction validation using computationally inexpensive linear inverse models (LIMs). Here we leverage these techniques in pursuit of a new multi-centennial field reconstruction of upper-ocean heat content (OHC), synthesizing model dynamics with observational constraints from proxy records. OHC is an important indicator of internal climate variability and responds to planetary energy imbalances. Therefore, a consistent extension of the OHC record in time will help inform aspects of low-frequency climate variability. We use the Community Climate System Model version 4 (CCSM4) and Max Planck Institute (MPI) last millennium simulations to derive the LIMs, and the PAGES2K v.2.0 proxy database to perform annually resolved reconstructions of upper-OHC, surface air temperature, and wind stress over the last 500 years. Annual OHC reconstructions and uncertainties for both the global mean and regional basins are compared against observational and reanalysis data. We then investigate differences in dynamical behavior at decadal and longer time scales between the reconstruction and simulations in the last-millennium Coupled Model Intercomparison Project version 5 (CMIP5). Preliminary investigation of 1-year forecast skill for an OHC-only LIM shows largely positive spatial grid point local anomaly correlations (LAC) with a global average LAC of 0.37. Compared to 1-year OHC persistence forecast LAC (global average LAC of 0.30), the LIM outperforms the persistence forecasts in the tropical Indo-Pacific region, the equatorial Atlantic, and in certain regions near the Antarctic Circumpolar Current. In other regions, the forecast correlations are less than the persistence case but still positive overall.

Land-Sea relationships of climate-related records: example of the Holocene in the eastern Canadian Arctic and Greenland

NASA Astrophysics Data System (ADS)

de Vernal, Anne; Fréchette, Bianca; Hillaire-Marcel, Claude

2017-04-01

Anne de Vernal, Bianca Fréchette, Claude Hillaire-Marcel Important progresses have been made to reconstruct climate and ocean changes through time. However, there is often a hiatus between the land-based climate reconstructions and paleoceanographical data. The reconstructed parameters are not the same (e.g. surface air temperature vs. sea-surface temperature). Moreover, the spatial (local to regional) and temporal dimensions (seasonal, annual to multi-decadal) of proxy-data are often inconsistent, thus preventing direct correlation of time series and often leading to uncertainties in multi-site, multi-proxy compilations. Here, we address the issue of land-sea relationships in the eastern Canadian Arctic-Baffin Bay-Labrador Sea-western Greenland based on the examination of different climate-related information from marine cores (dinocysts) collected nearshore vs. offshore, ice cores (isotopes), fjord and lake data (pollen). The combined information tends to indicate that "climate" changes are not easily neither adequately captured by temperature and temperature shifts. However, the seasonal contrast of temperatures seems to be a key parameter. Whereas it is often attenuated offshore, it is generally easy to reconstruct nearshore, where water stratification is usually stronger. The confrontation of data also shows a relationship between ice core data and sea-ice cover and/or sea-surface salinity, suggesting that air-sea exchanges in basins surrounding ice sheets play a significant role with respect to their isotopic composition. On the whole, combined onshore-offshore data consistently suggest a two-step shift towards optimal summer and winter conditions the circum Baffin Bay and northern Labrador Sea at 7.5 and 6 ka BP. These delayed optimal conditions seem to result from ice-meltwater discharges maintaining low salinity conditions in marine surface waters and thus a strong seasonality.

QTL affecting stress response to crowding in a rainbow trout broodstock population

USDA-ARS?s Scientific Manuscript database

Background Genomic analyses have the potential to impact selective breeding programs by identifying markers that serve as proxies for traits which are expensive or difficult to measure. Also, identifying genes affecting traits of interest enhances our understanding of their underlying biochemical ...

78 FR 48145 - Lemon Juice From Argentina: Continuation of Suspended Antidumping Duty Investigation

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-07

... DEPARTMENT OF COMMERCE International Trade Administration [A-357-818] Lemon Juice From Argentina... investigation on lemon juice from Argentina would likely lead to continuation or recurrence of dumping, and... suspended antidumping duty investigation on lemon juice from Argentina (``suspended investigation...

Cognitive rehabilitation therapy after acquired brain injury in Argentina: psychosocial outcomes in connection with the time elapsed before treatment initiation.

PubMed

Saux, Gastón; Demey, Ignacio; Rojas, Galeno; Feldberg, Carolina

2014-01-01

To examine the effect of cognitive rehabilitation therapy (CRT) on psychosocial outcomes in Argentinean patients with acquired brain injury (ABI), in connection with the time elapsed between injury and treatment initiation. Self-reported data from patients in a naturalistic setting was collected before and after CRT. An outpatient sample of 75 Spanish-speaking patients with cognitive disturbances secondary to ABI (49 male/26 female, age: 50.2 ± 20.1 years; education 14.3 ± 3.2 years) completed a set of scales on their daily living activities, memory self-perception, quality-of-life and mood. Single and multi-group analyses were conducted, considering pre- and post- responses and the time elapsed between injury and treatment initiation. The influence of socio-demographic moderators was controlled during comparisons. Results suggest an improvement in several psychosocial indicators after treatment. Additionally, correlations and group comparisons showed greater improvement in subjective memory and quality-of-life self-reports in patients who began treatment earlier than those who began treatment after a longer time period. Overall, results suggest that CRT is associated with positive results in different areas of the psychosocial domain and that post-injury time can mediate this effect.

Paleoclimatological perspective on the hydrometeorology of the Mekong Basin

NASA Astrophysics Data System (ADS)

Räsänen, T. A.; Lehr, C.; Mellin, I.; Ward, P. J.; Kummu, M.

2012-11-01

During recent decades the Mekong River has experienced substantial interannual variations between droughts and major floods. The causes of these variations have been sought in climate change and dam construction. However, so far little research has addressed whether these recent variations are significantly different to long-term variations in the past. Hence, the aim of our paper is to place the recent variations between droughts and floods into a historical and paleoclimatological context. To achieve this we analysed the Mekong's meteorological conditions over the period 1300-2005 with a basin scale approach by using the Monsoon Asia Drought Atlas (MADA), which is a Palmer Drought Severity Index (PDSI) dataset derived from tree-ring growth records. The correlation analyses, both in time and frequency domains, showed correlation between MADA and the Mekong's discharge over the period 1910-2005 which suggests that MADA can be used as proxy for the hydrometeorology of the Mekong Basin. We found that the meteorological conditions of the Mekong varied at multi-annual, decadal and centennial scales over the study period. We found two especially distinct features: firstly, multi-annual and decadal variation between prolonged wet and dry epochs; and secondly, epochs with higher or lower interannual variability between very dry and wet years. Furthermore we found two epochs with exceptionally large interannual variability, one at the beginning of 17th century and the other in the post 1950 epoch. Both epochs are characterized by distinct increases in variability between very wet and dry years. The variability in the post 1950 epoch is much higher compared to any of the other epochs included in this study. Thus, during recent decades the climate in the Mekong has exhibited features that have not been experienced for at least several centuries. These findings call for further climate research, particularly regarding increased climate variability, and resilient adaptation and development approaches in the basin.

Multiple incidence angle SIR-B experiment over Argentina

NASA Technical Reports Server (NTRS)

Cimino, Jobea; Casey, Daren; Wall, Stephen; Brandani, Aldo; Domik, Gitta; Leberl, Franz

1986-01-01

The Shuttle Imaging Radar (SIR-B), the second synthetic aperture radar (SAR) to fly aboard a shuttle, was launched on October 5, 1984. One of the primary goals of the SIR-B experiment was to use multiple incidence angle radar images to distinguish different terrain types through the use of their characteristic backscatter curves. This goal was accomplished in several locations including the Chubut Province of southern Argentina. Four descending image acquisitions were collected providing a multiple incidence angle image set. The data were first used to assess stereo-radargrammetric techniques. A digital elevation model was produced using the optimum pair of multiple incidence angle images. This model was then used to determine the local incidence angle of each picture element to generate curves of relative brightness vs. incidence angle. Secondary image products were also generated using the multi-angle data. The results of this work indicate that: (1) various forest species and various structures of a single species may be discriminated using multiple incidence angle radar imagery, and (2) it is essential to consider the variation in backscatter due to a variable incidence angle when analyzing and comparing data collected at varying frequencies and polarizations.

Argentina: Background and U.S. Relations

DTIC Science & Technology

2008-11-05

Comercio Internacional, Y Culto, Comunicado de la Cancillería Argentina, September 11, 2008. 43 A. Rebossio, "Fernández Acusa al FBI de Desestablizar...Argentina," El País (Madrid), September 13, 2008. 44 “Argentina Slams Witness in Cash Suitcase Scandal,” Associated Press Newswires, November 4, 2008

A stratigraphic network across the Subtropical Front in the central South Atlantic: Multi-parameter correlation of magnetic susceptibility, density, X-ray fluorescence and @d^1^8O records [rapid communication

NASA Astrophysics Data System (ADS)

Hofmann, Daniela I.; Fabian, Karl; Schmieder, Frank; Donner, Barbara; Bleil, Ulrich

2005-12-01

Computer aided multi-parameter signal correlation is used to develop a common high-precision age model for eight gravity cores from the subtropical and subantarctic South Atlantic. Since correlations between all pairs of multi-parameter sequences are used, and correlation errors between core pairs ( A, B) and ( B, C) are controlled by comparison with ( A, C), the resulting age model is called a stratigraphic network. Precise inter-core correlation is achieved using high-resolution records of magnetic susceptibility κ, wet bulk density ρ and X-ray fluorescence scans of elemental composition. Additional δ18O records are available for two cores. The data indicate nearly undisturbed sediment series and the absence of significant hiatuses or turbidites. After establishing a high-precision common depth scale by synchronously correlating four densely measured parameters (Fe, Ca, κ, ρ), the final age model is obtained by simultaneously fitting the aligned δ18O and κ records of the stratigraphic network to orbitally tuned oxygen isotope [J. Imbrie, J. D. Hays, D. G. Martinson, A. McIntyre, A. C. Mix, J. J. Morley, N. G. Pisias, W. L. Prell, N. J. Shackleton, The orbital theory of Pleistocene climate: support from a revised chronology of the marine δ18O record, in: A. Berger, J. Imbrie, J. Hays, G. Kukla, B. Saltzman (Eds.), Milankovitch and Climate: Understanding the Response to Orbital Forcing, Reidel Publishing, Dordrecht, 1984, pp. 269-305; D. Martinson, N. Pisias, J. Hays, J. Imbrie, T. C. Moore Jr., N. Shackleton, Age dating and the orbital theory of the Ice Ages: development of a high-resolution 0 to 300.000-Year chronostratigraphy, Quat. Res. 27 (1987) 1-29.] or susceptibility stacks [T. von Dobeneck, F.Schmieder, Using rock magnetic proxy records for orbital tuning and extended time series analyses into the super-and sub-Milankovitch Bands, in: G. Fischer, G. Wefer (Eds.), Use of proxies in paleoceanography: Examples from the South Atlantic, Springer-Verlag, Berlin (1999), pp. 601-633.]. Besides the detection and elimination of errors in single records, the stratigraphic network approach allows to check the intrinsic consistency of the final result by comparing it to the outcome of more restricted alignment procedures. The final South Atlantic stratigraphic network covers the last 400 kyr south and the last 1200 kyr north of the Subtropical Front (STF) and provides a highly precise age model across the STF representing extremely different sedimentary regimes. This allows to detect temporal shifts of the STF by mapping δMn / Fe. It turns out that the apparent STF movements by about 200 km are not directly related to marine oxygen isotope stages.

Holocene vegetation changes through Lac Ledro sediments (Trentino, Italy).

NASA Astrophysics Data System (ADS)

Joannin, Sebastien; Vannière, Boris; Galop, Didier; Magny, Michel; Gilli, Adrian; Chapron, Emmanuel; Wirth, Stéfanie; Anselmetti, Flavio; Desmet, Marc

2010-05-01

Lake Ledro is part of the French program ANR LAMA (coordinators: M. Magny and N. Combourieu Nebout) which aims to link Holocene paleoenvironmental changes along a north-south transect in Italy. Lake Ledro (652 m a.s.l.; Trentino, north-eastern Italy) is the northward component of the transect. It is located on the southern slope of the Alps and its catchment area covers 131 km2 with mountains culminating at 1500-2000 m. A multi-proxy approach based on biotic and abiotic indicators (lake-level, palynology, geochemistry and geophysic) was developed from deep and littoral cores, including sediment sequences in Early and Middle Bronze Age lake-shore archaeological sites. We aim reconstructing paleoenvironmental changes resulting from both climate and anthropic influences trough the entire Holocene. A deep master core was built after extracting twin cores from a non disturbed sediment zone recognised by seismic-reflexion investigations. The age-depth model is based on 13 AMS 14C ages measured on terrestrial plant macrofossils and the mean temporal resolution for analyses is ca 60 years. Palynological study shows the usual vegetation succession for the southern slope of the Alps. During the first part of the Holocene, abrupt changes are observed in pollen assemblages in relation to changes in other proxies (XRF and Magnetic Susceptibility) and correlate with cold events associated to the deglaciation in the North-Atlantic area. Cool episodes corresponding to the PreBoreal Oscillation (ca 11.3 ka cal BP) and 8.2 ka event are respectively characterized by stopping afforestation and a strong development of Abies in the local ecosystem. During the second part of the Holocene, two declines of arboreal pollen abundance are observed in relation with occurrences in both cereal and anthropic pollen indicators. These two phases are confirmed by increase in soil erosion as indicated by abiotic proxies. They give evidence of two successive steps for human settlement (Early-Middle Bronze Age and Iron Age) separated by forest development. In addition, XRF data allow two successive distinct palaeohydrological periods to be recognized into the Holocene. Finally, comparison between littoral and deep cores reinforces our interpretation and helps to disentangle climate and anthropic influences on the Holocene environment in the Central Mediterranean region.

Geo-social media as a proxy for hydrometeorological data for streamflow estimation and to improve flood monitoring

NASA Astrophysics Data System (ADS)

Restrepo-Estrada, Camilo; de Andrade, Sidgley Camargo; Abe, Narumi; Fava, Maria Clara; Mendiondo, Eduardo Mario; de Albuquerque, João Porto

2018-02-01

Floods are one of the most devastating types of worldwide disasters in terms of human, economic, and social losses. If authoritative data is scarce, or unavailable for some periods, other sources of information are required to improve streamflow estimation and early flood warnings. Georeferenced social media messages are increasingly being regarded as an alternative source of information for coping with flood risks. However, existing studies have mostly concentrated on the links between geo-social media activity and flooded areas. Thus, there is still a gap in research with regard to the use of social media as a proxy for rainfall-runoff estimations and flood forecasting. To address this, we propose using a transformation function that creates a proxy variable for rainfall by analysing geo-social media messages and rainfall measurements from authoritative sources, which are later incorporated within a hydrological model for streamflow estimation. We found that the combined use of official rainfall values with the social media proxy variable as input for the Probability Distributed Model (PDM), improved streamflow simulations for flood monitoring. The combination of authoritative sources and transformed geo-social media data during flood events achieved a 71% degree of accuracy and a 29% underestimation rate in a comparison made with real streamflow measurements. This is a significant improvement on the respective values of 39% and 58%, achieved when only authoritative data were used for the modelling. This result is clear evidence of the potential use of derived geo-social media data as a proxy for environmental variables for improving flood early-warning systems.

Hospital Stay as a Proxy Indicator for Severe Injury in Earthquakes: A Retrospective Analysis

PubMed Central

Zhao, Lu-Ping; Gerdin, Martin; Westman, Lina; Rodriguez-Llanes, Jose Manuel; Wu, Qi; van den Oever, Barbara; Pan, Liang; Albela, Manuel; Chen, Gao; Zhang, De-Sheng; Guha-Sapir, Debarati; von Schreeb, Johan

2013-01-01

Introduction Earthquakes are the most violent type of natural disasters and injuries are the dominant medical problem in the early phases after earthquakes. However, likely because of poor data availability, high-quality research on injuries after earthquakes is lacking. Length of hospital stay (LOS) has been validated as a proxy indicator for injury severity in high-income settings and could potentially be used in retrospective research of injuries after earthquakes. In this study, we assessed LOS as an adequate proxy indicator for severe injury in trauma survivors of an earthquake. Methods A retrospective analysis was conducted using a database of 1,878 injured patients from the 2008 Wenchuan earthquake. Our primary outcome was severe injury, defined as a composite measure of serious injury or resource use. Secondary outcomes were serious injury and resource use, analysed separately. Non-parametric receiver operating characteristics (ROC) and area under the curve (AUC) analysis was used to test the discriminatory accuracy of LOS when used to identify severe injury. An 0.7

Appraising timing response of paleoenvironmental proxies to the Bond cycle in the western Mediterranean over the last 20 kyr

NASA Astrophysics Data System (ADS)

Rodrigo-Gámiz, Marta; Martínez-Ruiz, Francisca; Rodríguez-Tovar, Francisco J.; Pardo-Igúzquiza, Eulogio; Ortega-Huertas, Miguel

2018-04-01

The timing of climate responses to the Bond cycle is investigated in the western Mediterranean. Periodicities had been previously reported in a marine sediment record from this region spanning the last 20 kyr, and registered by diverse paleoenvironmental proxies, in particular those associated with terrigenous input, redox conditions, productivity, sea surface temperature (SST) and salinity. Further cross-spectral analyses on these time series reveal leads-lags in the 1400 year climate cycle. Considering as reference a terrigenous input proxy (the K/Al ratio), all the paleoenvironmental proxies displayed time shifts varying from ca. 700 year to ca. 350 year. SST and salinity variations show a first leaded response with the inflow of cold and less salty Atlantic waters. Followed by a time lead of 525 year, progresively arid conditions with an increase of eolian dust transport to the area, given by the Zr/Al signal, are observed. The intensification of dust transport could have triggered a latest biological response, lead by 350 year, with an increase of productivity, as suggested by the Ba/Al ratio. Lastly changes in the Mediterranean thermohaline circulation, indicated by a selected redox proxy (the U/Th ratio), are observed. These results support that the oceanic response triggered the atmospheric response to the Bond cycle in the western Mediterranean. Changes in the North Atlantic Oscillation mode and in the Inter-Tropical Convergence Zone migrations with variations in the monsoon activity or Saharan winds system, are considered as main forcing mechanisms, with a complex relationship of the involved phenomena.

Hospital stay as a proxy indicator for severe injury in earthquakes: a retrospective analysis.

PubMed

Zhao, Lu-Ping; Gerdin, Martin; Westman, Lina; Rodriguez-Llanes, Jose Manuel; Wu, Qi; van den Oever, Barbara; Pan, Liang; Albela, Manuel; Chen, Gao; Zhang, De-Sheng; Guha-Sapir, Debarati; von Schreeb, Johan

2013-01-01

Earthquakes are the most violent type of natural disasters and injuries are the dominant medical problem in the early phases after earthquakes. However, likely because of poor data availability, high-quality research on injuries after earthquakes is lacking. Length of hospital stay (LOS) has been validated as a proxy indicator for injury severity in high-income settings and could potentially be used in retrospective research of injuries after earthquakes. In this study, we assessed LOS as an adequate proxy indicator for severe injury in trauma survivors of an earthquake. A retrospective analysis was conducted using a database of 1,878 injured patients from the 2008 Wenchuan earthquake. Our primary outcome was severe injury, defined as a composite measure of serious injury or resource use. Secondary outcomes were serious injury and resource use, analysed separately. Non-parametric receiver operating characteristics (ROC) and area under the curve (AUC) analysis was used to test the discriminatory accuracy of LOS when used to identify severe injury. An 0.7

77 FR 73021 - Lemon Juice From Argentina: Final Results of the Expedited First Sunset Review of the Suspended...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-07

... DEPARTMENT OF COMMERCE International Trade Administration [A-357-818] Lemon Juice From Argentina... duty investigation on lemon juice from Argentina. The Department has conducted an expedited sunset... suspended antidumping duty investigation on lemon juice from Argentina, pursuant to section 751(c) of the...

77 FR 45334 - Honey From Argentina: Preliminary Rescission of Antidumping Duty New Shipper Review

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-31

... DEPARTMENT OF COMMERCE International Trade Administration [A-357-812] Honey From Argentina... antidumping duty order on honey from Argentina for the period of December 1, 2010, through November 30, 2011... on honey from Argentina was published on December 10, 2001.\\1\\ On January 3, 2012, the Department...

76 FR 80870 - Notice of Determination of Pest-Free Areas in Mendoza Province, Argentina

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-27

... ;D=APHIS-2010-0032. The first commenter acknowledged Argentina's history of successful Medfly control...] Notice of Determination of Pest-Free Areas in Mendoza Province, Argentina AGENCY: Animal and Plant Health... Southern and Central Oases in the southern half of Mendoza Province in Argentina as pest-free areas for...

76 FR 51934 - Determination of Pest-Free Areas in Mendoza Province, Argentina; Request for Comments

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-19

... acknowledged Argentina's history of successful Medfly control efforts, but stated that APHIS should not relax...] Determination of Pest-Free Areas in Mendoza Province, Argentina; Request for Comments AGENCY: Animal and Plant... received a request from the Government of Argentina to recognize additional areas as pest- free areas for...

77 FR 65670 - Honey From Argentina: Final Rescission of Antidumping Duty New Shipper Review

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-30

... DEPARTMENT OF COMMERCE International Trade Administration [A-357-812] Honey From Argentina: Final... order on honey from Argentina for the period of December 1, 2010, through November 30, 2011.\\1\\ We...\\ See Honey from Argentina: Preliminary Rescission of Antidumping Duty New Shipper Review, 77 FR 45334...

76 FR 5332 - Honey From Argentina: Notice of Initiation of Antidumping Duty New Shipper Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-31

... DEPARTMENT OF COMMERCE International Trade Administration [A-357-812] Honey From Argentina: Notice... received a request for a new shipper review of the antidumping duty order on honey from Argentina. See Notice of Antidumping Duty Order: Honey From Argentina, 66 FR 63672 (December 10, 2001) (Order). In...

Cross contrast multi-channel image registration using image synthesis for MR brain images.

PubMed

Chen, Min; Carass, Aaron; Jog, Amod; Lee, Junghoon; Roy, Snehashis; Prince, Jerry L

2017-02-01

Multi-modal deformable registration is important for many medical image analysis tasks such as atlas alignment, image fusion, and distortion correction. Whereas a conventional method would register images with different modalities using modality independent features or information theoretic metrics such as mutual information, this paper presents a new framework that addresses the problem using a two-channel registration algorithm capable of using mono-modal similarity measures such as sum of squared differences or cross-correlation. To make it possible to use these same-modality measures, image synthesis is used to create proxy images for the opposite modality as well as intensity-normalized images from each of the two available images. The new deformable registration framework was evaluated by performing intra-subject deformation recovery, intra-subject boundary alignment, and inter-subject label transfer experiments using multi-contrast magnetic resonance brain imaging data. Three different multi-channel registration algorithms were evaluated, revealing that the framework is robust to the multi-channel deformable registration algorithm that is used. With a single exception, all results demonstrated improvements when compared against single channel registrations using the same algorithm with mutual information. Copyright © 2016 Elsevier B.V. All rights reserved.

Ecological analysis of the health effects of income inequality in Argentina.

PubMed

De Maio, Fernando G

2008-05-01

Despite a large body of empirical literature, a consensus has not been reached concerning the health effects of income inequality. This study contributes to ongoing debates by examining the robustness of the income inequality-population health relationship in Argentina, using five different income inequality indexes (each sensitive to inequalities in differing parts of the income spectrum) and five measures of population health. Cross-sectional, ecological study. Income and self-reported morbidity data from Argentina's 2001 Encuesta de Condiciones de Vida (Survey of living conditions) were analysed at the provincial level. Provincial rates of male/female life expectancy and infant mortality were drawn from the Instituto Nacional de Estadistica y Censos database. Life expectancy was correlated in the expected direction with provincial-level income inequality (operationalized as the Gini coefficient) for both males (r=-0.55, P<0.01) and females (r=-0.61, P<0.01), but this association was not robust for all five income inequality indexes. In contrast, infant mortality, self-reported poor health and self-reported activity limitation were not correlated with any of the income inequality indexes. This study adds further complexity to the literature on the health effects of income inequality by highlighting the important effects of operational definitions. Mortality and morbidity data cannot be used as reasonably interchangeable variables (a common practice in this literature), and the choice of income inequality indicator may influence the results.

First report of parasitism by Hexametra boddaertii (Nematoda: Ascaridae) in Oxyrhopus guibei (Serpentes: Colubridae).

PubMed

Peichoto, María E; Sánchez, Matías N; López, Ariel; Salas, Martín; Rivero, María R; Teibler, Pamela; Toledo, Gislayne de Melo; Tavares, Flávio L

2016-07-15

The current study summarizes the postmortem examination of a specimen of Oxyrhopus guibei (Serpentes, Colubridae) collected in Iguazu National Park (Argentina), and found deceased a week following arrival to the serpentarium of the National Institute of Tropical Medicine (Argentina). Although the snake appeared to be in good health, a necropsy performed following its death identified the presence of a large number of roundworms in the coelomic cavity, with indications of peritonitis and serosal adherence. Additional observations from the necropsy revealed small calcifications in the mesothelium of the coelomic cavity; solid and expressive content in the gallbladder; massive gastrointestinal obstruction due to nematodes; and lung edema and congestion. Histopathological analyses of lung sections also showed proliferative heterophilic and histiocytic pneumonia. Parasites isolated from both the intestine and coelomic cavity were identified as Hexametra boddaertii by a combination of light and scanning electron microscopic examination. Results from this necropsy identify O. guibei as a new host for H. boddaertii, and is the first report of a natural infection by Hexametra in Argentina. Since Hexametra parasites may contribute to several pathological conditions in humans, and with the recent availability of O. guibei specimens through the illegal pet trade, it is necessary to consider the possibility of zoonotic helminth transmission of Hexametra from snake to human. Copyright © 2016 Elsevier B.V. All rights reserved.

Century-Long Warming Trends in the Upper Water Column of Lake Tanganyika.

PubMed

Kraemer, Benjamin M; Hook, Simon; Huttula, Timo; Kotilainen, Pekka; O'Reilly, Catherine M; Peltonen, Anu; Plisnier, Pierre-Denis; Sarvala, Jouko; Tamatamah, Rashid; Vadeboncoeur, Yvonne; Wehrli, Bernhard; McIntyre, Peter B

2015-01-01

Lake Tanganyika, the deepest and most voluminous lake in Africa, has warmed over the last century in response to climate change. Separate analyses of surface warming rates estimated from in situ instruments, satellites, and a paleolimnological temperature proxy (TEX86) disagree, leaving uncertainty about the thermal sensitivity of Lake Tanganyika to climate change. Here, we use a comprehensive database of in situ temperature data from the top 100 meters of the water column that span the lake's seasonal range and lateral extent to demonstrate that long-term temperature trends in Lake Tanganyika depend strongly on depth, season, and latitude. The observed spatiotemporal variation in surface warming rates accounts for small differences between warming rate estimates from in situ instruments and satellite data. However, after accounting for spatiotemporal variation in temperature and warming rates, the TEX86 paleolimnological proxy yields lower surface temperatures (1.46 °C lower on average) and faster warming rates (by a factor of three) than in situ measurements. Based on the ecology of Thaumarchaeota (the microbes whose biomolecules are involved with generating the TEX86 proxy), we offer a reinterpretation of the TEX86 data from Lake Tanganyika as the temperature of the low-oxygen zone, rather than of the lake surface temperature as has been suggested previously. Our analyses provide a thorough accounting of spatiotemporal variation in warming rates, offering strong evidence that thermal and ecological shifts observed in this massive tropical lake over the last century are robust and in step with global climate change.

A wind proxy based on migrating dunes at the Baltic coast: statistical analysis of the link between wind conditions and sand movement

NASA Astrophysics Data System (ADS)

Bierstedt, Svenja E.; Hünicke, Birgit; Zorita, Eduardo; Ludwig, Juliane

2017-07-01

We statistically analyse the relationship between the structure of migrating dunes in the southern Baltic and the driving wind conditions over the past 26 years, with the long-term aim of using migrating dunes as a proxy for past wind conditions at an interannual resolution. The present analysis is based on the dune record derived from geo-radar measurements by Ludwig et al. (2017). The dune system is located at the Baltic Sea coast of Poland and is migrating from west to east along the coast. The dunes present layers with different thicknesses that can be assigned to absolute dates at interannual timescales and put in relation to seasonal wind conditions. To statistically analyse this record and calibrate it as a wind proxy, we used a gridded regional meteorological reanalysis data set (coastDat2) covering recent decades. The identified link between the dune annual layers and wind conditions was additionally supported by the co-variability between dune layers and observed sea level variations in the southern Baltic Sea. We include precipitation and temperature into our analysis, in addition to wind, to learn more about the dependency between these three atmospheric factors and their common influence on the dune system. We set up a statistical linear model based on the correlation between the frequency of days with specific wind conditions in a given season and dune migration velocities derived for that season. To some extent, the dune records can be seen as analogous to tree-ring width records, and hence we use a proxy validation method usually applied in dendrochronology, cross-validation with the leave-one-out method, when the observational record is short. The revealed correlations between the wind record from the reanalysis and the wind record derived from the dune structure is in the range between 0.28 and 0.63, yielding similar statistical validation skill as dendroclimatological records.

Carbohydrates and phenols as quantitative molecular vegetation proxies in peats

NASA Astrophysics Data System (ADS)

Kaiser, K.; Benner, R. H.

2012-12-01

Vegetation in peatlands is intricately linked to local environmental conditions and climate. Here we use chemical analyses of carbohydrates and phenols to reconstruct paleovegetation in peat cores collected from 56.8°N (SIB04), 58.4°N (SIB06), 63.8°N (G137) and 66.5°N (E113) in the Western Siberian Lowland. Lignin phenols (vanillyl and syringyl phenols) were sensitive biomarkers for vascular plant contributions and provided additional information on the relative contributions of angiosperm and gymnosperm plants. Specific neutral sugar compositions allowed identification of sphagnum mosses, sedges (Cyperaceae) and lichens. Hydroxyphenols released by CuO oxidation were useful tracers of sphagnum moss contributions. The three independent molecular proxies were calibrated with a diverse group of peat-forming plants to yield quantitative estimates (%C) of vascular plant, sphagnum moss and lichen contributions in peat core samples. Correlation analysis indicated the three molecular proxies produced fairly similar results for paleovegetation compositions, generally within the error interval of each approach (≤26%). The lignin-based method generally lead to higher estimates of vascular plant vegetation. Several significant deviations were also observed due to different reactivities of carbohydrate and phenolic polymers during peat decomposition. Rapid vegetation changes on timescales of 50-200 years were observed in the southern cores SIB04 and SIB06 over the last 2000 years. Vanillyl and syringyl phenol ratios indicated these vegetation changes were largely due to varying inputs of angiosperm and gymnosperm plants. The northern permafrost cores G137 and E113 showed a more stable development. Lichens briefly replaced sphagnum mosses and vascular plants in both of these cores. Shifts in vegetation did not correlate well with Northern hemisphere climate variability over the last 2000 years. This suggested that direct climate forcing of peatland dynamics was overridden by local or regional ecosystem variables. Overall, these molecular proxies offer robust complementary approaches to reconstruct paleovegetation in peat in addition to traditional methods such as macrofossil and pollen analyses.

Multi-Method Provenance Analysis of Namibian Desert Sand

NASA Astrophysics Data System (ADS)

Vermeesch, P.; Garzanti, E.

2014-12-01

Mineralogical, geochemical and geochronological provenance proxies each have their own strengths and weaknesses: a. Bulk geochemistry, framework petrography and heavy mineral compositions can differentiate between source areas characterised by different lithologies, but are sensitive to hydraulic sorting and chemical alteration. b. Detrital zircon U-Pb geochronology is insensitive to winnowing effects, but is 'blind' to lithologies devoid of zircon and cannot differentiate between first cycle and recycled sediments. c. Cosmogenic neon isotopes can be used to identify different generations of surface exposure while simultaneously tracking different magmatic sources. The challenge is then to combine these different proxies into a self consistent story, and do so in as objective a manner as possible. We here present a case study of Namibia's Namib Sand Sea and Skeleton Coast ergs, in which all the aforementioned methods have been combined using a three-way multidimensional scaling (aka INDividual Differences SCALing or INDSCAL) analysis: 1. Each of the datasets was represented by a 'dissimilarity matrix' of pairwise distances between samples. 2. The set of these matrices was fed into the INDSCAL algorithm, which produces two pieces of graphical output: the 'group configuration', which is a scatter plot or 'map' in which similar samples plot close together and dissimilar samples plot far apart, and the 'proxy weights', in which not the samples but the proxies are plotted according to the weight they attached to the 'group configuration' axes. The INDSCAL map of the Namibia dataset indicates that (a) long-shore drift of Orange River sediments dominates the coastal sediment compositions all along the Namibian coast until Angola, and (b) that light and heavy minerals tell complementary parts of the provenance story.

Advantages of Task-Specific Multi-Objective Optimisation in Evolutionary Robotics.

PubMed

Trianni, Vito; López-Ibáñez, Manuel

2015-01-01

The application of multi-objective optimisation to evolutionary robotics is receiving increasing attention. A survey of the literature reveals the different possibilities it offers to improve the automatic design of efficient and adaptive robotic systems, and points to the successful demonstrations available for both task-specific and task-agnostic approaches (i.e., with or without reference to the specific design problem to be tackled). However, the advantages of multi-objective approaches over single-objective ones have not been clearly spelled out and experimentally demonstrated. This paper fills this gap for task-specific approaches: starting from well-known results in multi-objective optimisation, we discuss how to tackle commonly recognised problems in evolutionary robotics. In particular, we show that multi-objective optimisation (i) allows evolving a more varied set of behaviours by exploring multiple trade-offs of the objectives to optimise, (ii) supports the evolution of the desired behaviour through the introduction of objectives as proxies, (iii) avoids the premature convergence to local optima possibly introduced by multi-component fitness functions, and (iv) solves the bootstrap problem exploiting ancillary objectives to guide evolution in the early phases. We present an experimental demonstration of these benefits in three different case studies: maze navigation in a single robot domain, flocking in a swarm robotics context, and a strictly collaborative task in collective robotics.

Assessment of the Coral Temperature Proxies for Orbicella faveolata in the Southwestern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Vara, M. A.; DeLong, K. L.; Herrmann, A. D.; Ouellette, G., Jr.; Richey, J. N.

2017-12-01

Coral Sr/Ca is a robust proxy of sea surface temperature (SST); however, discrepancies in the Sr/Ca-SST relationship among colonies of the same species may reduce confidence in absolute temperature reconstructions. Furthermore, terrestrial carbonate weathering can provide local sources of Sr and/or Ca to coastal waters that may disrupt the temperature-based coral Sr/Ca signal. Thus other trace metal SST proxies have been suggested to circumvent these issues (Li/Ca, Li/Mg, and Sr-U). Coral Ba/Ca has been used as a proxy for runoff and coastal upwelling, and therefore may be used to identify intervals when these processes overprint the Sr/Ca-SST signal. This study tests multiple coral SST proxies using reproducibility assessments to determine the best performing SST proxy. We conduct these assessments with cores recovered in 1991 by the U.S. Geological Survey from five Orbicella faveolata colonies from three reefs offshore of Veracruz, Mexico (19.06°N, 96.93°W) in water depths varying from 3 to 12 m. Previous studies found micromilling the complex skeletal structure of O. faveolata challenging and that monthly resolution may not recover full seasonal cycles. We use a laser ablation inductively coupled plasma mass spectrometer to simultaneously sample this coral's structure at weekly intervals spanning 8 years for Li/Ca, Li/Mg, Sr-U, Sr/Ca, and Ba/Ca. Here we found coral Li/Ca means and seasonal variations are similar among colonies thus this proxy may capture absolute temperature and SST variability. Similar to previous research with Porites corals, Li/Ca in these O. faveolata corals decreases with increases in SST with similar slopes and intercepts. During the last 10 years of these corals' lives, coral Sr/Ca analysis reveals a mean shift among colonies suggesting an external source could have disrupted the Sr/Ca signal, possibly seasonal runoff and/or winter upwelling common to Veracruz waters. Coral Ba/Ca analyses reveals elevated values in winters that coincide with increases in coral Sr/Ca in the deeper colony suggesting upwelling is occurring at that location. However, the coral Ba/Ca does not coincide with increase coral Sr/Ca in the shallower coral indicating no direct influence from runoff. Coral Li/Mg and Sr-U do not show substantial seasonal variations as expected with a coral-SST proxy.

A review of the South American monsoon history as recorded in stable isotopic proxies over the past two millennia

NASA Astrophysics Data System (ADS)

Vuille, M.; Burns, S. J.; Taylor, B. L.; Cruz, F. W.; Bird, B. W.; Abbott, M. B.; Kanner, L. C.; Cheng, H.; Novello, V. F.

2012-08-01

We review the history of the South American summer monsoon (SASM) over the past ~2000 yr based on high-resolution stable isotope proxies from speleothems, ice cores and lake sediments. Our review is complemented by an analysis of an isotope-enabled atmospheric general circulation model (GCM) for the past 130 yr. Proxy records from the monsoon belt in the tropical Andes and SE Brazil show a very coherent behavior over the past 2 millennia with significant decadal to multidecadal variability superimposed on large excursions during three key periods: the Medieval Climate Anomaly (MCA), the Little Ice Age (LIA) and the current warm period (CWP). We interpret these three periods as times when the SASM's mean state was significantly weakened (MCA and CWP) and strengthened (LIA), respectively. During the LIA each of the proxy archives considered contains the most negative δ18O values recorded during the entire record length. On the other hand, the monsoon strength is currently rather weak in a 2000-yr historical perspective, rivaled only by the low intensity during the MCA. Our climatic interpretation of these archives is consistent with our isotope-based GCM analysis, which suggests that these sites are sensitive recorders of large-scale monsoon variations. We hypothesize that these centennial-scale climate anomalies were at least partially driven by temperature changes in the Northern Hemisphere and in particular over the North Atlantic, leading to a latitudinal displacement of the ITCZ and a change in monsoon intensity (amount of rainfall upstream over the Amazon Basin). This interpretation is supported by several independent records from different proxy archives and modeling studies. Although ENSO is the main forcing for δ18O variability over tropical South America on interannual time scales, our results suggest that its influence may be significantly modulated by North Atlantic climate variability on longer time scales. Finally, our analyses indicate that isotopic proxies, because of their ability to integrate climatic information on large spatial scales, could complement more traditional proxies such as tree rings or documentary evidence. Future climate reconstruction efforts could potentially benefit from including isotopic proxies as large-scale predictors in order to better constrain past changes in the atmospheric circulation.

Results from the FIN-2 formal comparison

NASA Astrophysics Data System (ADS)

Connolly, Paul; Hoose, Corinna; Liu, Xiaohong; Moehler, Ottmar; Cziczo, Daniel; DeMott, Paul

2017-04-01

During the Fifth International Ice Nucleation Workshop (FIN-2) at the AIDA Ice Nucleation facility in Karlsruhe, Germany in March 2015, a formal comparison of ice nucleation measurement methods was conducted. During the experiments the samples of ice nucleating particles were not revealed to the instrument scientists, hence this was referred to as a "blind comparison". The two samples used were later revealed to be Arizona Test Dust and an Argentina soil sample. For these two samples seven mobile ice nucleating particle counters sampled directly from the AIDA chamber or from the aerosol preparation chamber at specified temperatures, whereas filter samples were taken for two offline deposition nucleation instruments. Wet suspension methods for determining IN concentrations were also used with 10 different methods employed. For the wet suspension methods experiments were conducted using INPs collected from the air inside the chambers (impinger sampling) and INPs taken from the bulk samples (vial sampling). Direct comparisons of the ice nucleating particle concentrations are reported as well as derived ice nucleation active site densities. The study highlights the difficulties in performing such analyses, but generally indicates that there is reasonable agreement between the wet suspension techniques. It is noted that ice nucleation efficiency derived from the AIDA chamber (quantified using the ice active surface site density approach) is higher than that for the cold stage techniques. This is both true for the Argentina soil sample and, to a lesser extent, for the Arizona Test Dust sample too. Other interesting effects were noted: for the ATD the impinger sampling demonstrated higher INP efficiency at higher temperatures (>255 K) than the vial sampling, but agreed at the lower temperatures (<255K), whereas the opposite was true for the Argentina soil sample. The results are analysed to better understand the performance of the various techniques and to address any size-sorting effects and / or sampling line loses.

First comparative transcriptomic analysis of wild adult male and female Lutzomyia longipalpis, vector of visceral leishmaniasis.

PubMed

McCarthy, Christina B; Santini, María Soledad; Pimenta, Paulo F P; Diambra, Luis A

2013-01-01

Leishmaniasis is a vector-borne disease with a complex epidemiology and ecology. Visceral leishmaniasis (VL) is its most severe clinical form as it results in death if not treated. In Latin America VL is caused by the protist parasite Leishmania infantum (syn. chagasi) and transmitted by Lutzomyia longipalpis. This phlebotomine sand fly is only found in the New World, from Mexico to Argentina. However, due to deforestation, migration and urbanisation, among others, VL in Latin America is undergoing an evident geographic expansion as well as dramatic changes in its transmission patterns. In this context, the first VL outbreak was recently reported in Argentina, which has already caused 7 deaths and 83 reported cases. Insect vector transcriptomic analyses enable the identification of molecules involved in the insect's biology and vector-parasite interaction. Previous studies on laboratory reared Lu. longipalpis have provided a descriptive repertoire of gene expression in the whole insect, midgut, salivary gland and male reproductive organs. Nevertheless, the study of wild specimens would contribute a unique insight into the development of novel bioinsecticides. Given the recent VL outbreak in Argentina and the compelling need to develop appropriate control strategies, this study focused on wild male and female Lu. longipalpis from an Argentine endemic (Posadas, Misiones) and a Brazilian non-endemic (Lapinha Cave, Minas Gerais) VL location. In this study, total RNA was extracted from the sand flies, submitted to sequence independent amplification and high-throughput pyrosequencing. This is the first time an unbiased and comprehensive transcriptomic approach has been used to analyse an infectious disease vector in its natural environment. Transcripts identified in the sand flies showed characteristic profiles which correlated with the environment of origin and with taxa previously identified in these same specimens. Among these, various genes represented putative targets for vector control via RNA interference (RNAi).

First Comparative Transcriptomic Analysis of Wild Adult Male and Female Lutzomyia longipalpis, Vector of Visceral Leishmaniasis

PubMed Central

McCarthy, Christina B.; Santini, María Soledad; Pimenta, Paulo F. P.; Diambra, Luis A.

2013-01-01

Leishmaniasis is a vector-borne disease with a complex epidemiology and ecology. Visceral leishmaniasis (VL) is its most severe clinical form as it results in death if not treated. In Latin America VL is caused by the protist parasite Leishmania infantum (syn. chagasi) and transmitted by Lutzomyia longipalpis. This phlebotomine sand fly is only found in the New World, from Mexico to Argentina. However, due to deforestation, migration and urbanisation, among others, VL in Latin America is undergoing an evident geographic expansion as well as dramatic changes in its transmission patterns. In this context, the first VL outbreak was recently reported in Argentina, which has already caused 7 deaths and 83 reported cases. Insect vector transcriptomic analyses enable the identification of molecules involved in the insect's biology and vector-parasite interaction. Previous studies on laboratory reared Lu. longipalpis have provided a descriptive repertoire of gene expression in the whole insect, midgut, salivary gland and male reproductive organs. Nevertheless, the study of wild specimens would contribute a unique insight into the development of novel bioinsecticides. Given the recent VL outbreak in Argentina and the compelling need to develop appropriate control strategies, this study focused on wild male and female Lu. longipalpis from an Argentine endemic (Posadas, Misiones) and a Brazilian non-endemic (Lapinha Cave, Minas Gerais) VL location. In this study, total RNA was extracted from the sand flies, submitted to sequence independent amplification and high-throughput pyrosequencing. This is the first time an unbiased and comprehensive transcriptomic approach has been used to analyse an infectious disease vector in its natural environment. Transcripts identified in the sand flies showed characteristic profiles which correlated with the environment of origin and with taxa previously identified in these same specimens. Among these, various genes represented putative targets for vector control via RNA interference (RNAi). PMID:23554910

More Cercospora Species Infect Soybeans across the Americas than Meets the Eye

PubMed Central

Soares, Ana Paula Gomes; Guillin, Eduardo A.; Borges, Leandro Luiz; da Silva, Amanda C. T.; de Almeida, Álvaro M. R.; Grijalba, Pablo E.; Gottlieb, Alexandra M.; Bluhm, Burton H.; de Oliveira, Luiz Orlando

2015-01-01

Diseases of soybean caused by Cercospora spp. are endemic throughout the world’s soybean production regions. Species diversity in the genus Cercospora has been underestimated due to overdependence on morphological characteristics, symptoms, and host associations. Currently, only two species (Cercospora kikuchii and C. sojina) are recognized to infect soybean; C. kikuchii causes Cercospora leaf blight (CLB) and purple seed stain (PSS), whereas C. sojina causes frogeye leaf spot. To assess cryptic speciation among pathogens causing CLB and PSS, phylogenetic and phylogeographic analyses were performed with isolates from the top three soybean producing countries (USA, Brazil, and Argentina; collectively accounting for ~80% of global production). Eight nuclear genes and one mitochondrial gene were partially sequenced and analyzed. Additionally, amino acid substitutions conferring fungicide resistance were surveyed, and the production of cercosporin (a polyketide toxin produced by many Cercospora spp.) was assessed. From these analyses, the long-held assumption of C. kikuchii as the single causal agent of CLB and PSS was rejected experimentally. Four cercosporin-producing lineages were uncovered with origins (about 1 Mya) predicted to predate agriculture. Some of the Cercospora spp. newly associated with CLB and PSS appear to represent undescribed species; others were not previously reported to infect soybeans. Lineage 1, which contained the ex-type strain of C. kikuchii, was monophyletic and occurred in Argentina and Brazil. In contrast, lineages 2 and 3 were polyphyletic and contained wide-host range species complexes. Lineage 4 was monophyletic, thrived in Argentina and the USA, and included the generalist Cercospora cf. flagellaris. Interlineage recombination was detected, along with a high frequency of mutations linked to fungicide resistance in lineages 2 and 3. These findings point to cryptic Cercospora species as underappreciated global considerations for soybean production and phytosanitary vigilance, and urge a reassessment of host-specificity as a diagnostic tool for Cercospora. PMID:26252018

More Cercospora Species Infect Soybeans across the Americas than Meets the Eye.

PubMed

Soares, Ana Paula Gomes; Guillin, Eduardo A; Borges, Leandro Luiz; Silva, Amanda C T da; Almeida, Álvaro M R de; Grijalba, Pablo E; Gottlieb, Alexandra M; Bluhm, Burton H; Oliveira, Luiz Orlando de

2015-01-01

Diseases of soybean caused by Cercospora spp. are endemic throughout the world's soybean production regions. Species diversity in the genus Cercospora has been underestimated due to overdependence on morphological characteristics, symptoms, and host associations. Currently, only two species (Cercospora kikuchii and C. sojina) are recognized to infect soybean; C. kikuchii causes Cercospora leaf blight (CLB) and purple seed stain (PSS), whereas C. sojina causes frogeye leaf spot. To assess cryptic speciation among pathogens causing CLB and PSS, phylogenetic and phylogeographic analyses were performed with isolates from the top three soybean producing countries (USA, Brazil, and Argentina; collectively accounting for ~80% of global production). Eight nuclear genes and one mitochondrial gene were partially sequenced and analyzed. Additionally, amino acid substitutions conferring fungicide resistance were surveyed, and the production of cercosporin (a polyketide toxin produced by many Cercospora spp.) was assessed. From these analyses, the long-held assumption of C. kikuchii as the single causal agent of CLB and PSS was rejected experimentally. Four cercosporin-producing lineages were uncovered with origins (about 1 Mya) predicted to predate agriculture. Some of the Cercospora spp. newly associated with CLB and PSS appear to represent undescribed species; others were not previously reported to infect soybeans. Lineage 1, which contained the ex-type strain of C. kikuchii, was monophyletic and occurred in Argentina and Brazil. In contrast, lineages 2 and 3 were polyphyletic and contained wide-host range species complexes. Lineage 4 was monophyletic, thrived in Argentina and the USA, and included the generalist Cercospora cf. flagellaris. Interlineage recombination was detected, along with a high frequency of mutations linked to fungicide resistance in lineages 2 and 3. These findings point to cryptic Cercospora species as underappreciated global considerations for soybean production and phytosanitary vigilance, and urge a reassessment of host-specificity as a diagnostic tool for Cercospora.

Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation

NASA Astrophysics Data System (ADS)

Rahmstorf, Stefan; Box, Jason E.; Feulner, Georg; Mann, Michael E.; Robinson, Alexander; Rutherford, Scott; Schaffernicht, Erik J.

2015-05-01

Possible changes in Atlantic meridional overturning circulation (AMOC) provide a key source of uncertainty regarding future climate change. Maps of temperature trends over the twentieth century show a conspicuous region of cooling in the northern Atlantic. Here we present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970. Since 1990 the AMOC seems to have partly recovered. This time evolution is consistently suggested by an AMOC index based on sea surface temperatures, by the hemispheric temperature difference, by coral-based proxies and by oceanic measurements. We discuss a possible contribution of the melting of the Greenland Ice Sheet to the slowdown. Using a multi-proxy temperature reconstruction for the AMOC index suggests that the AMOC weakness after 1975 is an unprecedented event in the past millennium (p > 0.99). Further melting of Greenland in the coming decades could contribute to further weakening of the AMOC.

Multi-state residential transaction estimates of solar photovoltaic system premiums

DOE PAGES

Hoen, Ben; Adomatis, Sandra; Jackson, Thomas; ...

2017-07-10

We report that as of the second quarter of 2016 more than 1.1 million solar photovoltaic (PV) homes exist in the US. Capturing the value these PV systems add to home sales is therefore important. Our study enhances the PV-home-valuation literature by analyzing 22,822 home sales, of which 3951 have PV, and which span eight states during 2002–2013. We also, for the first time, compare premiums with contributory value estimates derived from the present value of saved energy costs (income approach) and, separately, the replacement cost of systems at the time of sale (cost approach) to examine market signals. Wemore » find home buyers are consistently willing to pay PV home premiums across various states, housing and PV markets, and home types; average premiums equate to approximately $4/W or $15,000 for an average-sized 3.6-kW PV system. We find that a replacement cost net of state and federal incentives is a better proxy for premiums than gross installed costs, and that the income approach is a good signal if it accounts for tiered volumetric retail rates. Finally, other results include detailed premium analyses for PV home sub-populations.« less

Putting the rise of the Inca Empire within a climatic and land management context

NASA Astrophysics Data System (ADS)

Chepstow-Lusty, A. J.; Frogley, M. R.; Bauer, B. S.; Leng, M. J.; Boessenkool, K. P.; Carcaillet, C.; Ali, A. A.; Gioda, A.

2009-03-01

The rapid expansion of the Inca from the Cuzco area of highland Peru produced the largest empire in the New World between ca. AD 1400-1532. Although this meteoric rise may in part be due to the adoption of innovative societal strategies, supported by a large labour force and standing army, we argue that this would not have been possible without increased crop productivity, which was linked to more favourable climatic conditions. A multi-proxy, high-resolution 1200-year lake sediment record was analysed at Marcacocha, 12 km north of Ollantaytambo, in the heartland of the Inca Empire. This record reveals a period of sustained aridity that began from AD 880, followed by increased warming from AD 1100 that lasted beyond the arrival of the Spanish in AD 1532. These increasingly warmer conditions allowed the Inca and their predecessors the opportunity to exploit higher altitudes from AD 1150, by constructing agricultural terraces that employed glacial-fed irrigation, in combination with deliberate agroforestry techniques. There may be some important lessons to be learnt today from these strategies for sustainable rural development in the Andes in the light of future climate uncertainty.

Multi-state residential transaction estimates of solar photovoltaic system premiums

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoen, Ben; Adomatis, Sandra; Jackson, Thomas

We report that as of the second quarter of 2016 more than 1.1 million solar photovoltaic (PV) homes exist in the US. Capturing the value these PV systems add to home sales is therefore important. Our study enhances the PV-home-valuation literature by analyzing 22,822 home sales, of which 3951 have PV, and which span eight states during 2002–2013. We also, for the first time, compare premiums with contributory value estimates derived from the present value of saved energy costs (income approach) and, separately, the replacement cost of systems at the time of sale (cost approach) to examine market signals. Wemore » find home buyers are consistently willing to pay PV home premiums across various states, housing and PV markets, and home types; average premiums equate to approximately $4/W or $15,000 for an average-sized 3.6-kW PV system. We find that a replacement cost net of state and federal incentives is a better proxy for premiums than gross installed costs, and that the income approach is a good signal if it accounts for tiered volumetric retail rates. Finally, other results include detailed premium analyses for PV home sub-populations.« less

Extreme precipitation in the Polish Carpathians in the 20th century in the context of last 500 years

NASA Astrophysics Data System (ADS)

Limanowka, Danuta; Cebulak, Elzbieta; Pyrc, Robert

2010-05-01

Extreme weather phenomena together with their exceptional course and intensity have always been dangerous for people. In the historical documents such phenomena were marked as basic disasters. First notes about weather phenomena were made in Polish lands in the 10th century. Most information concerns floods caused by intensive rains. Using the data base created within the Millennium project, extreme precipitation cases exceeding 100 mm were analysed. In each case, the intensive precipitation was followed by a summer flood in the Polish Carpathians in the Upper Vistula River basin. Data from the period of instrumental measurements in the 20th century were studied in detail by the analysis of the frequency of occurrence and the spatial and temporal distribution. The results were referred to last 500 years. The information obtained gives approximate image of extreme precipitation in the historical times in Polish lands. All available multi-proxy data were used. Newspapers' notes concerning described phenomena from 1848-1850 published in Kraków were used to complete and verify the quality of data from the early instrumental period and also to complete the data from the period of the Second World War.

Insights into hydroclimatic variability of Southern California since 125 ka, from multi-proxy analyses of alpine lakes

NASA Astrophysics Data System (ADS)

Glover, K. C.; MacDonald, G. M.; Kirby, M.

2016-12-01

Hydroclimatic variability is especially important in California, a water-stressed and increasingly populous region. We assess the range of past hydroclimatic sensitivity and variability in the San Bernardino Mountains of Southern California based on 125 ka of lacustrine sediment records. Geochemistry, charcoal and pollen highlight periods of sustained moisture, aridity and sudden variability driven by orbital and oceanic variations. Marine Isotope Stage 3 (MIS 3) is one such period of greater moisture availability that lasted c. 30 kyr, with smaller-scale perturbations likely reflect North Atlantic Dansgaard-Oeschgar events. Past glacial periods, MIS 4 and MIS 2, display high-amplitude changes. These include periods of reduced forest cover that span millennia, indicating long-lasting aridity. Rapid forest expansion also occurs, marking sudden shifts towards wet conditions. Fire regimes have also changed in tandem with hydroclimate and vegetation. Higher-resolution analysis of the past 10 ka shows that Southern California hydroclimate was broadly similar to other regions of the Southwest and Great Basin, including an orbital and oceanic-driven wet Early Holocene, dry Mid-Holocene, and highly variable Late Holocene. Shorter-term pluvial conditions occur throughout the Holocene, with episodic moisture likely derived from a Pacific source.

The role of C3 and C4 grasses to interannual variability in remotely sensed ecosystem performance over the US Great Plains

USGS Publications Warehouse

Ricotta, C.; Reed, Bradley C.; Tieszen, Larry L.

2003-01-01

Time integrated normalized difference vegetation index (ΣNDVI) derived from National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) multi-temporal imagery over a 10-year period (1989–1998) was used as a surrogate for primary production to investigate the impact of interannual climate variability on grassland performance for central and northern US Great Plains. First, the contribution of C3 and C4 species abundance to the major grassland ecosystems of the US Great Plains is described. Next, the relation between mean ΣNDVI and the ΣNDVI coefficient of variation (CV ΣNDVI) used as a proxy for interannual climate variability is analysed. Results suggest that the differences in the long-term climatic control over ecosystem performance approximately coincide with changes between C3- and C4-dominant grassland classes. Variation in remotely sensed net primary production over time is higher for the southern and western plains grasslands (primarily C4 grasslands), whereas the C3-dominated classes in the northern and eastern portion of the US Great Plains, generally show lower CV ΣNDVI values.

A High-Resolution Lipid Biomarker Perspective on North Iceland Shelf Marine Climate over the Last Millennium

NASA Astrophysics Data System (ADS)

Harning, D.; Sepúlveda, J.; Andrews, J. T.; Cabedo-Sanz, P.; Belt, S. T.; Marchitto, T. M.; Stoner, J. S.; Geirsdóttir, Á.; Miller, G. H.

2017-12-01

Icelandic climate is vulnerable to variations in the dominance of competing Arctic and Atlantic ocean currents. The boundary between these water masses delineates the Polar Front, which today occupies the North Iceland Shelf (NIS). To date, Holocene oceanographic reconstructions along the NIS have employed a variety of proxies including Mg/Ca and δ18O of benthic and planktonic foraminifera, quartz and calcite wt%, the alkenone unsaturation index (Uk'37) and biotic species assemblages. Sea surface temperature (SST) proxies are primarily derived from phytoplankton resulting in a seasonal bias toward spring/summer SST. Furthermore, SST proxies can be influenced by additional confounding variables (e.g. salinity, nutrients, depth habitat of biota) resulting in markedly different Holocene temperature reconstructions between proxy datasets. To evaluate the similarities and discrepancies between various marine proxies, we investigate a high-resolution sediment core collected from the central North Iceland Shelf (B997-316GGC, 658 m depth). Sedimentation covers the last millennium, which captures the transition from the Medieval Warm Period to the Little Ice Age. Age control is constrained by 14C dates and paleomagnetic secular variation. To assess marine surface productivity and sea ice conditions, we analyze quartz and calcite wt% via XRD and a series of highly branched isoprenoid biomarkers. Quantitative paleotemperature estimates are derived from a novel combination of Mg/Ca of foraminifera and two lipid biomarker indices, Uk'37 from Prymnesiophyte alkenones and TEX86 from Thaumarchaeota glycerol dialkyl glycerol tetraethers (GDGTs). The latter TEX86 record is the first paleo application in Icelandic waters, which a recent local calibration study suggests may reflect annual or winter sub-surface (0-200 m) temperatures. Our paleotemperature records are bolstered by the analysis of additional sediment core tops, which expand the established Icelandic calibrations. Finally, we perform statistical analyses in an effort to extract a robust record of paleoceanographic change and to test the applicability of various proxies in high-latitude paleoclimate studies.

Distribution of biologic, anthropogenic, and volcanic constituents as a proxy for sediment transport in the San Francisco Bay Coastal System

USGS Publications Warehouse

McGann, Mary; Erikson, Li H.; Wan, Elmira; Powell, Charles; Maddocks, Rosalie F.; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

2013-01-01

Although conventional sediment parameters (mean grain size, sorting, and skewness) and provenance have typically been used to infer sediment transport pathways, most freshwater, brackish, and marine environments are also characterized by abundant sediment constituents of biological, and possibly anthropogenic and volcanic, origin that can provide additional insight into local sedimentary processes. The biota will be spatially distributed according to its response to environmental parameters such as water temperature, salinity, dissolved oxygen, organic carbon content, grain size, and intensity of currents and tidal flow, whereas the presence of anthropogenic and volcanic constituents will reflect proximity to source areas and whether they are fluvially- or aerially-transported. Because each of these constituents have a unique environmental signature, they are a more precise proxy for that source area than the conventional sedimentary process indicators. This San Francisco Bay Coastal System study demonstrates that by applying a multi-proxy approach, the primary sites of sediment transport can be identified. Many of these sites are far from where the constituents originated, showing that sediment transport is widespread in the region. Although not often used, identifying and interpreting the distribution of naturally-occurring and allochthonous biologic, anthropogenic, and volcanic sediment constituents is a powerful tool to aid in the investigation of sediment transport pathways in other coastal systems.

Multi-proxy evidence for Late Pleistocene-Holocene climatic and environmental changes in Lop-Nur, Xinjiang, Northwest China

USGS Publications Warehouse

Luo, C.; Yang, D.; Peng, Z.; Zhang, Z.; Weiguo, L.; He, J.; Zhou, C.

2008-01-01

A 10.35-m-long sediment core from the Luobei depression in Lop-Nur, Xinjiang, Northwest China, provides detailed information about environmental changes during the Late Pleistocene. The samples taken every 5 cm of the core were analyzed for 10 environmental proxies, including magnetic susceptibility, granularity, chroma, carbonate and loss on ignition (LOI), and pH value. The chronology data are provided by the uranium/thorium disequilibrium dates. The sediments of the section were deposited during the last 32000 years. The results of analysis of 10 proxies were examined using multivariate statistical analysis, and the principal components were calculated. According to the results, the Late Pleistocene sequence contains four climatic and environmental stages appearing in the cycles of cold-wet and warm-dry changes. During 10-9 ka BP, it was the earliest warm episode in the Holocene. Environmental changes in this district were restricted by global change, as suggested by the analysis of glacial-interglacial cycles. But it was different from the mutative trend of a monsoon region in East China because of its own characteristics, which was the situation of cold-wet and warm-dry climate-environment change. The candidate reason may be the uplift of the Tibet Plateau and the westerly wind circulation. ?? Science Press, Institute of Geochemistry, CAS and Springer-Verlag GmbH 2008.

Do factors related to combustion-based sources explain ...

EPA Pesticide Factsheets

Introduction: Spatial heterogeneity of effect estimates in associations between PM2.5 and total non-accidental mortality (TNA) in the United States (US), is an issue in epidemiology. This study uses rate ratios generated from the Multi-City/Multi-Pollutant study (1999-2005) for 313 core-based statistical areas (CBSA) and their metropolitan divisions (MD) to examine combustion-based sources of heterogeneity.Methods: For CBSA/MDs, area-specific log rate ratios (betas) were derived from a model adjusting for time, an interaction with age-group, day of week, and natural splines of current temperature, current dew point, and unconstrained temperature at lags 1, 2, and 3. We assessed the heterogeneity in the betas by linear regression with inverse variance weights, using average NO2, SO2, and CO, which may act as a combustion source proxy, and these pollutants’ correlations with PM2.5. Results: We found that weighted mean PM2.5 association (0.96 percent increase in total non-accidental mortality for a 10 µg/m3 increment in PM2.5) increased by 0.26 (95% confidence interval 0.08 , 0.44) for an interquartile change (0.2) in the correlation of SO2 and PM2.5., but betas showed less dependence on the annual averages of SO2 or NO2. Spline analyses suggest departures from linearity, particularly in a model that examined correlations between PM2.5 and CO.Conclusions: We conclude that correlations between SO2 and PM2.5 as an indicator of combustion sources explains some hete

Moss stable isotopes (carbon-13, oxygen-18) and testate amoebae reflect environmental inputs and microclimate along a latitudinal gradient on the Antarctic Peninsula.

PubMed

Royles, Jessica; Amesbury, Matthew J; Roland, Thomas P; Jones, Glyn D; Convey, Peter; Griffiths, Howard; Hodgson, Dominic A; Charman, Dan J

2016-07-01

The stable isotope compositions of moss tissue water (δ(2)H and δ(18)O) and cellulose (δ(13)C and δ(18)O), and testate amoebae populations were sampled from 61 contemporary surface samples along a 600-km latitudinal gradient of the Antarctic Peninsula (AP) to provide a spatial record of environmental change. The isotopic composition of moss tissue water represented an annually integrated precipitation signal with the expected isotopic depletion with increasing latitude. There was a weak, but significant, relationship between cellulose δ(18)O and latitude, with predicted source water inputs isotopically enriched compared to measured precipitation. Cellulose δ(13)C values were dependent on moss species and water content, and may reflect site exposure to strong winds. Testate amoebae assemblages were characterised by low concentrations and taxonomic diversity, with Corythion dubium and Microcorycia radiata types the most cosmopolitan taxa. The similarity between the intra- and inter-site ranges measured in all proxies suggests that microclimate and micro-topographical conditions around the moss surface were important determinants of proxy values. Isotope and testate amoebae analyses have proven value as palaeoclimatic, temporal proxies of climate change, whereas this study demonstrates that variations in isotopic and amoeboid proxies between microsites can be beyond the bounds of the current spatial variability in AP climate.

A School-Level Proxy Measure for Individual-Level Poverty Using School-Level Eligibility for Free and Reduced-Price Meals.

PubMed

Day, Sophia E; Hinterland, Kinjia; Myers, Christa; Gupta, Leena; Harris, Tiffany G; Konty, Kevin J

2016-03-01

Socioeconomic status (SES) impacts health outcomes. The Youth Risk Behavior Survey (YRBS), like many school-based data sources, lacks individual-level poverty information. We propose using school-level percentages of student eligibility for free/reduced-price meals (%FRPM) as a proxy for individual-level poverty. Using the New York City (NYC) 2009 YRBS, we created school-level poverty quartiles to append to individual YRBS records by ranking schools by %FRPM. We compared this with 2 other school-level poverty measures using students' home and school neighborhood-level poverty and measured the association of these 3 school-level proxies with individual's household income. Last, we evaluated health outcomes by race/ethnicity and poverty to demonstrate the importance of accounting for poverty. The school-level measure that used %FRPM had the strongest association with household income. When the school-level individual poverty proxy was included in illustrative analyses using YRBS data, patterns by poverty within race/ethnicity emerged that were not seen when looking at race/ethnicity alone. Using a poverty measure to analyze school-based data will provide a better understanding of the impact of SES on health outcomes. Based on our evaluation, when individual-level information is not available, we propose using school-level %FRPM, which are publicly available throughout the United States. © 2016, American School Health Association.

Measuring health-related quality of life in population-based studies of coronary heart disease: comparing six generic indexes and a disease-specific proxy score.

PubMed

Garster, Noelle C; Palta, Mari; Sweitzer, Nancy K; Kaplan, Robert M; Fryback, Dennis G

2009-11-01

To compare HRQoL differences with CHD in generic indexes and a proxy CVD-specific score in a nationally representative sample of U.S. adults. The National Health Measurement Study, a cross-sectional random-digit-dialed telephone survey of adults aged 35-89, administered the EQ-5D, QWB-SA, HUI2, HUI3, SF-36v2 (yielding PCS, MCS, and SF-6D), and HALex. Analyses compared 3,350 without CHD (group 1), 265 with CHD not taking chest pain medication (group 2), and 218 with CHD currently taking chest pain medication (group 3), with and without adjustment for demographic variables and comorbidities. Data on 154 patients from heart failure clinics were used to construct a proxy score utilizing generic items probing CVD symptoms. Mean scores differed between CHD groups for all indexes with and without adjustment (P < 0.0001 for all except MCS P = 0.018). Unadjusted group 3 versus 1 differences were about three times larger than for group 2 versus 1. Standardized differences for the proxy score were similar to those for generic indexes, and were about 1.0 for all except MCS for group 3 versus 1. Generic indexes capture differences in HRQoL in population-based studies of CHD similarly to a score constructed from questions probing CVD-specific symptoms.

Acculturation and Bicultural Efficacy Effects on Chinese American Immigrants’ Diabetes and Health Management

PubMed Central

Chun, Kevin M.; Kwan, Christine M. L.; Strycker, Lisa A.; Chesla, Catherine A.

2016-01-01

The primary goal of this study was to examine effects of bicultural efficacy, or perceived confidence in dealing with bicultural acculturation stressors, on type 2 diabetes management and health for first-generation, Cantonese-speaking, Chinese American immigrants (N=162) recruited for a larger community-based diabetes intervention study (Chesla et al., 2013). The current study also tested whether a new Bicultural Efficacy in Health Management (BEFF-HM) scale is a more robust predictor of diabetes and health outcomes than proxy (years in the U.S.) and general acculturation measures. Hierarchical regression analyses of cross-sectional data revealed that high BEFF-HM was significantly related to positive outcomes on five of six diabetes and health measures as hypothesized after accounting for participant characteristics, proxy and general acculturation measures, and social support. Proxy and general acculturation measures failed to predict any study outcome supporting our secondary hypothesis that BEFF-HM is a better predictor of Chinese American immigrants’ diabetes and health management. An immigrant-focused research approach advances understanding of acculturation and bicultural efficacy effects on health by identifying key acculturation domains for study. PMID:27412776

A Skilful Marine Sclerochronological Network Based Reconstruction of North Atlantic Subpolar Gyre Dynamics

NASA Astrophysics Data System (ADS)

Reynolds, D.; Hall, I. R.; Slater, S. M.; Scourse, J. D.; Wanamaker, A. D.; Halloran, P. R.; Garry, F. K.

2017-12-01

Spatial network analyses of precisely dated, and annually resolved, tree-ring proxy records have facilitated robust reconstructions of past atmospheric climate variability and the associated mechanisms and forcings that drive it. In contrast, a lack of similarly dated marine archives has constrained the use of such techniques in the marine realm, despite the potential for developing a more robust understanding of the role basin scale ocean dynamics play in the global climate system. Here we show that a spatial network of marine molluscan sclerochronological oxygen isotope (δ18Oshell) series spanning the North Atlantic region provides a skilful reconstruction of basin scale North Atlantic sea surface temperatures (SSTs). Our analyses demonstrate that the composite marine series (referred to as δ18Oproxy_PC1) is significantly sensitive to inter-annual variability in North Atlantic SSTs (R=-0.61 P<0.01) and surface air temperatures (SATs; R=-0.67, P<0.01) over the 20th century. Subpolar gyre (SPG) SSTs dominates variability in the δ18Oproxy_PC1 series at sub-centennial frequencies (R=-0.51, P<0.01). Comparison of the δ18Oproxy_PC1 series against variability in the strength of the European Slope Current and maximum North Atlantic meridional overturning circulation derived from numeric climate models (CMIP5), indicates that variability in the SPG region, associated with the strength of the surface currents of the North Atlantic, are playing a significant role in shaping the multi-decadal scale SST variability over the industrial era. These analyses demonstrate that spatial networks developed from sclerochronological archives can provide powerful baseline archives of past ocean variability that can facilitate the development of a quantitative understanding for the role the oceans play in the global climate systems and constraining uncertainties in numeric climate models.

The presence of vanadium in groundwater of southeastern extreme the pampean region Argentina Relationship with other chemical elements.

PubMed

Fiorentino, Carmen E; Paoloni, Juan D; Sequeira, Mario E; Arosteguy, Pedro

2007-08-15

Changes in the quality of groundwater resources are related to the presence and concentration of contaminants, especially trace elements such as arsenic, boron, fluoride and vanadium. Vanadium is a rare element naturally abundant, generally found in combination with other elements. Vanadium pentoxide is known to have aneugenic effects. Thus, a study was carried out to assess the presence of vanadium in the groundwater of the southeastern pampean region of Argentina, which constitutes the main water supply for the local population. Statistical and correlational analyses were applied to identify possible interrelationships between vanadium and another chemical elements. Vanadium was found in all groundwater samples. The minimum and maximum vanadium concentrations found were 0.05 mg/l and 2.47 mg/l, respectively. Vanadium is significantly correlated with other trace elements such as arsenic, fluoride and boron. The interrelationship between vanadium and the presence of volcanic glass in sediments is not significant as expected.

[Surveillance of health care errors. An overview of the published data in Argentina].

PubMed

Codermatz, Marcela A; Trillo, Carolina; Berenstein, Graciela; Ortiz, Zulma

2006-01-01

In the last decades, public health surveillance extended its scope of study to new fields, such as medical errors, in order to improve patient safety. This study was aimed to review all the evidence produced in Argentina about the surveillance of medical errors. An exhaustive literature search was performed. A total of 4656 abstracts were assessed (150 MEDLINE, 145 LILACS, and 4361 hand searched abstracts). Of them, 52 were analysed and 8 were considered relevant for health care error surveillance. Different approaches were used to study medical errors. Some of them have focused on patient safety and others on medical malpractice. There is still a need to improve the surveillance of this type of event. Mainly, the quality reports of study design and surveillance attributes were unclear. A critical appraisal and synthesis of all relevant studies on health care errors may help to understand not only the state of the art, but also to define research priorities.

Hydrogeochemical and isotopic characterisation of groundwater in a sand-dune phreatic aquifer on the northeastern coast of the province of Buenos Aires, Argentina.

PubMed

Carretero, Silvina C; Dapeña, Cristina; Kruse, Eduardo E

2013-01-01

This contribution presents the hydrochemical and isotopic characterisation of the phreatic aquifer located in the Partido de la Costa, province of Buenos Aires, Argentina. In the sand-dune barrier geomorphological environment, groundwater is mainly a low-salinity Ca-HCO3 and Na-HCO3-type, being in general suitable for drinking, whereas in the continental plain (silty clay sediments), groundwater is a Na-Cl type with high salinity and unsuitable for human consumption. The general isotopic composition of the area ranges from-6.8 to-4.3 ‰ for δ(18)O and from-39 to-21 ‰ for δ(2)H, showing that rainwater rapidly infiltrates into the sandy substrate and reaches the water table almost without significant modification in its isotopic composition. These analyses, combined with other chemical parameters, made it possible to corroborate that in the eastern area of the phreatic aquifer, there is no contamination from marine salt water.

The conceptualisation of health-related quality of life in decision-making by intensive care physicians: A qualitative inquiry.

PubMed

Haines, Dr Kimberley J; Remedios, Louisa; Berney, Sue C; Knott, Dr Cameron; Denehy, Linda

2017-05-01

To explore how intensive care physicians conceptualise and prioritise patient health-related quality of life in their decision-making. General qualitative inquiry using elements of Grounded Theory. Six ICU physicians participated. A large, closed, mixed ICU at a university-affiliated hospital, Australia. Three themes emerged: (1) Multi-dimensionality of HRQoL-HRQoL was described as difficult to understand; the patient was viewed as the best informant. Proxy information on HRQoL and health preferences was used to direct clinical care, despite not always being trusted. (2) Prioritisation of HRQoL within decision-making-this varied across the patient's health care trajectory. Premorbid HRQoL was prioritised when making admission decisions and used to predict future HRQoL. (3) Role of physician in decision-making-the physicians described their role as representing society with peers influencing their decision-making. All participants considered their practice to be similar to their peers, referring to their practice as the "middle of the road". This is a novel finding, emphasising other important influences in high-stakes decision-making. Critical care physicians conceptualised HRQoL as a multi-dimensional subjective construct. Patient (or proxy) voice was integral in establishing patient HRQoL and future health preferences. HRQoL was important in high stakes decision-making including initiating invasive and burdensome therapies or in redirecting therapeutic goals. Copyright © 2016 Australian College of Critical Care Nurses Ltd. All rights reserved.

Validating the use of scintillation proxies to study ionospheric scintillation over the Ugandan region

NASA Astrophysics Data System (ADS)

Amabayo, Emirant B.; Jurua, Edward; Cilliers, Pierre J.

2015-06-01

In this study, we compare the standard scintillation indices (S4 and σΦ) from a SCINDA receiver with scintillation proxies (S4p and | sDPR |) derived from two IGS GPS receivers. Amplitude (S4) and phase (σΦ) scintillation data were obtained from the SCINDA installed at Makerere University (0.34°N, 32.57°E). The corresponding amplitude (S4p) and phase (| sDPR |) scintillation proxies were derived from data archived by IGS GPS receivers installed at Entebbe (0.04°N, 32.44°E) and Mbarara (0.60°S, 30.74°E). The results show that for most of the cases analysed in this study, σΦ and | sDPR | are in agreement. Amplitude scintillation occurrence estimated using the S4p are fairly consistent with the standard S4, mainly between 17:00 UT and 21:00 UT, despite a few cases of over and under estimation of scintillation levels by S4p. Correlation coefficients between σΦ and the | sDPR | proxy revealed positive correlation. Generally, S4p and S4 exhibits both moderate and strong positive correlation. TEC depletions associated with equatorial plasma bubbles are proposed as the cause of the observed scintillation over the region. These equatorial plasma bubbles were evident along the ray paths to satellites with PRN 2, 15, 27 and 11 as observed from MBAR and EBBE. In addition to equatorial plasma bubbles, atmospheric gravity waves with periods similar to those of large scale traveling ionospheric disturbances were also observed as one of the mechanisms for scintillation occurrence. The outcome of this study implies that GPS derived scintillation proxies can be used to quantify scintillation levels in the absence of standard scintillation data in the equatorial regions.

Analysis of Population Substructure in Two Sympatric Populations of Gran Chaco, Argentina

PubMed Central

Sevini, Federica; Yao, Daniele Yang; Lomartire, Laura; Barbieri, Annalaura; Vianello, Dario; Ferri, Gianmarco; Moretti, Edgardo; Dasso, Maria Cristina; Garagnani, Paolo; Pettener, Davide; Franceschi, Claudio; Luiselli, Donata; Franceschi, Zelda Alice

2013-01-01

Sub-population structure and intricate kinship dynamics might introduce biases in molecular anthropology studies and could invalidate the efforts to understand diseases in highly admixed populations. In order to clarify the previously observed distribution pattern and morbidity of Chagas disease in Gran Chaco, Argentina, we studied two populations (Wichí and Criollos) recruited following an innovative bio-cultural model considering their complex cultural interactions. By reconstructing the genetic background and the structure of these two culturally different populations, the pattern of admixture, the correspondence between genealogical and genetic relationships, this integrated perspective had the power to validate data and to link the gap usually relying on a singular discipline. Although Wichí and Criollos share the same area, these sympatric populations are differentiated from the genetic point of view as revealed by Non Recombinant Y Chromosome genotyping resulting in significantly high Fst values and in a lower genetic variability in the Wichí population. Surprisingly, the Amerindian and the European components emerged with comparable amounts (20%) among Criollos and Wichí respectively. The detailed analysis of mitochondrial DNA showed that the two populations have as much as 87% of private haplotypes. Moreover, from the maternal perspective, despite a common Amerindian origin, an Andean and an Amazonian component emerged in Criollos and in Wichí respectively. Our approach allowed us to highlight that quite frequently there is a discrepancy between self-reported and genetic kinship. Indeed, if self-reported identity and kinship are usually utilized in population genetics as a reliable proxy for genetic identity and parental relationship, in our model populations appear to be the result not only and not simply of the genetic background but also of complex cultural determinants. This integrated approach paves the way to a rigorous reconstruction of demographic and cultural history as well as of bioancestry and propensity to diseases of Wichí and Criollos. PMID:23717528

Impact of surface processes and climate variability on clumped isotope thermometry of soil carbonates, southern Central Andes, Argentina (Invited)

NASA Astrophysics Data System (ADS)

Huntington, K. W.; Peters, N.; Roe, G.; Hoke, G. D.; Eiler, J.

2010-12-01

Soil carbonates archive a potentially rich record of past climate, but rates of pedogenic carbonate formation, erosion, and deposition impact how the isotopic composition and formation temperature of carbonate-bearing paleosols reflect the local environmental conditions under which they form. We investigate these processes using conventional stable isotope (δ18O and δ13C) and clumped isotope thermometry data for Quaternary pedogenic carbonates from the southern Central Andes at ~33°S, Argentina. The study area spans over 2 km of relief in the Río Mendoza and Río de las Cuevas valleys, accessing a range of mean annual temperature conditions and vegetative cover and exhibiting large seasonal variations in temperature, precipitation, and soil moisture. Variations in soil conditions influence carbonate precipitation and dissolution reactions and the rate and depth of pedogenic carbonate formation. Because soil temperature varies predictably as a function of depth in the soil and seasonal and secular variations in air temperature, clumped isotope thermometry of samples collected in soil pits offers a direct way to estimate the seasonality of pedogenic carbonate formation and potential biases in the long-term climate record. We explore potential complications due to the effects of radiative solar heating on the relationship between air and soil temperatures by examining clumped isotope thermometry results in the context of site-to-site variations in vegetative cover. Temperature estimates from clumped isotope thermometry of pedogenic carbonate collected 5-110 cm below geomorphically stable soil surfaces from 1200-3400 m a.s.l. are compared to temperature profiles predicted by simple rule-based models of soil carbonate formation. The models use climate reanalysis daily diagnostic data (soil temperature, soil moisture, and latent heat flux as a proxy for evaporation) and weather station data as input to assess how varying rates of pedogenic carbonate formation integrated over millennial timescales might impact the geologic record of temperature and isotopic composition.

Modern foraminifera assemblages in the Amundsen Sea Embayment

NASA Astrophysics Data System (ADS)

Ewa Jernas, Patrycja; Kuhn, Gerhard; Hillenbrand, Claus-Dieter; Lander Rasmussen, Tine; Forwick, Matthias; Mackensen, Andreas; Schröder, Michael; Smith, James; Klages, Johann Philipp

2015-04-01

The West Antarctic Ice Sheet (WAIS) is considered the most unstable part of the Antarctic Ice Sheet. As the WAIS is mostly grounded below sea level, its stability is of great concern. A collapse of large parts of the WAIS would result in a significant global sea-level rise. At present, the WAIS shows dramatic ice loss in its Amundsen Sea sector, especially in Pine Island Bay. Pine Island Glacier (PIG) is characterised by fast flow, major thinning and rapid grounding-line retreat. Its mass los over recent decades is generally attributed to melting caused by the inflow of warm Circumpolar Deep Water (CDW). Future melting of PIG may result in a sea level tipping point, because it could trigger widespread collapse of the WAIS, especially when considering ongoing climate change. Our research project aims to establish proxies (integration of foraminifera, sediment properties and oceanographic data) for modern environmental conditions by analysing seafloor surface sediments along a transect from the glacier proximal settings to the middle-outer shelf in the eastern Amundsen Sea Embayment. These proxies will then be applied on sediment records spanning the Holocene back to the Last Glacial Maximum for reconstructing spatial and temporal variations of CDW upwelling and ice-ocean interactions during the past c. 23,000 years. We will present preliminary results from the analyses of ten short marine sediment cores (multi and box cores) collected during expeditions JR179 (2008) and ANT-XXVI/3 (2010) along a transect from inner Pine Island Bay to the middle-outer shelf part of the Abbot Palaeo-Ice Stream Trough at water depths ranging from 458 m (middle shelf) to 1444 m (inner shelf). The sediment cores are currently investigated for distribution patterns of planktonic and benthic foraminifera and grain-size distribution at 1 cm resolution. Core tops (0-10 cm) were stained with Rose Bengal for living benthic foraminifera investigations. The chronology of the cores will be based on 210Pb and calibrated 14C dates. First results reveal the presence of living benthic foraminifera in surface sediments of all investigated cores suggesting that modern seabed surfaces were recovered. Moreover, a core retrieved from a water depth of 793 m in the Abbot Palaeo-Ice Stream Trough shows particularly high abundances of planktonic foraminifera Neogloboquadrina pachyderma.

First characterisation of the "Rumi-Pana" rock avalanche deposits (Famatina Range, La Rioja, Argentina)

NASA Astrophysics Data System (ADS)

Santiago Pullarello, José; Derron, Marc-Henri; Penna, Ivanna; Leiva, Alicia; Jaboyadoff, Michel

2017-04-01

Active mountain fronts are subject to large scale slope collapses which have the capacity to run long distances on piedmont areas. Along time, fluvial activity and other gravitatory processes can intensively erode and mask primary features related to the collapses. Therefore, to reconstruct the history of their occurrence, further analyses are needed, e.g. sedimentologic analyses. This work focuses on the occurrence of large rock avalanches in the Vinchina region, La Rioja (28°43'27.81'' S / 68°00'25.42'' W) on the western side of the Famatina range(Argentina). Here, photointerpretation of high resolution satellite images (Google Earth) allowed us to identify two rock avalanches, main scarps developed at 2575 and 2750 m a.s.l. . There are no absolute ages for these deposits, however, comparing their preservation degree with those dated further north (in similar climatic and landscape dynamics contexts [i]), we can suggest these rock avalanches took place during the Pleistocene. We carried out a fieldwork survey in this remote area, including classical landslide mapping, structural analysis, deposits characterization and sampling. The deposits reach the valley bottom (at around 1700 m a.s.l.) with runouts about 5 and 5.3 km long. In one of the cases, the morphology of the deposit is well preserved, allowing to reconstruct accurately its extension. However, in the second case, the deposits are strongly eroded by courses draining the mountain front, therefore further analyses should be done to reconstruct its extension. In addition to morphologic interpretations, a multiscale grain-size analysis was done to differentiate rock avalanches from other hillslope deposits: (1) 3D surface models of surface plots (5x5m) have been built by SfM photogrammetry; 2) classical sieving and 3) laser grain-size analysis of deposits. Samples were collected on different parts of the slope, but also along cross sections through the avalanche deposit. This deposits characterization will be combined with results from mapping and image analysis in order to provide a first description of the sequence and extension of events related to the evolution of this mountain front. [i] Hermanns et Strecker, Structural and lithological controls on large Quaternary rock avalanches (sturzstroms) in arid northwestern Argentina, Geological Society of America Bulletin 1999.

A short history of the beginnings of hospital information systems in Argentina.

PubMed

Yácubsohn, V

2012-01-01

To describe the development of early health information systems in Argentina and their impact on the development of professional societies in the discipline The first hospital information systems and health surveillance systems in Argentina are described and related to the rise of professional organizations for health informatics. The early health information systems in Argentina are related to precursor developments in medical informatics. Argentina saw a number of hospital information systems developed starting in 1977, which had an important influence on the practice and experience in medical informatics in the country, and the participation of Argentine professionals in national, regional, and international activities in the field.

Constraining the temperature history of the past millennium using early instrumental observations

NASA Astrophysics Data System (ADS)

Brohan, P.

2012-12-01

The current assessment that twentieth-century global temperature change is unusual in the context of the last thousand years relies on estimates of temperature changes from natural proxies (tree-rings, ice-cores etc.) and climate model simulations. Confidence in such estimates is limited by difficulties in calibrating the proxies and systematic differences between proxy reconstructions and model simulations - notable differences include large differences in multi-decadal variability between proxy reconstructions, and big uncertainties in the effect of volcanic eruptions. Because the difference between the estimates extends into the relatively recent period of the early nineteenth century it is possible to compare them with a reliable instrumental estimate of the temperature change over that period, provided that enough early thermometer observations, covering a wide enough expanse of the world, can be collected. By constraining key aspects of the reconstructions and simulations, instrumental observations, inevitably from a limited period, can reduce reconstruction uncertainty throughout the millennium. A considerable quantity of early instrumental observations are preserved in the world's archives. One organisation which systematically made observations and collected the results was the English East-India Company (EEIC), and 900 log-books of EEIC ships containing daily instrumental measurements of temperature and pressure have been preserved in the British Library. Similar records from voyages of exploration and scientific investigation are preserved in published literature and the records in National Archives. Some of these records have been extracted and digitised, providing hundreds of thousands of new weather records offering an unprecedentedly detailed view of the weather and climate of the late eighteenth and early nineteenth centuries. The new thermometer observations demonstrate that the large-scale temperature response to the Tambora eruption and the 1809 eruption was modest (perhaps 0.5C). This provides a powerful out-of-sample validation for the proxy reconstructions --- supporting their use for longer-term climate reconstructions. However, some of the climate model simulations in the CMIP5 ensemble show much larger volcanic effects than this --- such simulations are unlikely to be accurate in this respect.

High-resolution Record of Holocene Climate, Vegetation, and Fire from a Raised Peat Bog, Prince Edward Island, Canadian Maritimes

NASA Astrophysics Data System (ADS)

Peros, M. C.; Chan, K.; Ponsford, L.; Carroll, J.; Magnan, G.

2014-12-01

Raised peat bogs receive all precipitation and nutrients from the atmosphere and are thus widely used archives for information on past environments and climates. In this paper we provide high-resolution multi-proxy data from a raised bog from northeastern Prince Edward Island, located in the Gulf of St. Lawrence, Canada. We studied testate amoeba (a proxy for water table depth), macrocharcoal (a proxy for local-scale fire), peat humification (a proxy for decomposition), plant macrofossils (indicative of local-scale vegetation), and organic matter content (yielding carbon accumulation rates) from a 5.5 m long core lifted from the center of Baltic Bog. Eleven AMS radiocarbon dates show that peat accumulation began before 9000 cal yr BP and continued almost uninterrupted until the present. The macrofossil data show that a transition from a sedge-dominated fen to a sphagnum-dominated bog occurred around 8000 cal yr BP, and sphagnum remained dominant in the bog throughout most of the Holocene. A testate amoeba-based reconstruction of water table depth indicates that conditions were drier during the early Holocene (~8000 to 5000 cal yr BP) and became gradually wetter into the late Holocene. In addition, a number of higher frequency shifts in precipitation are inferred throughout the Holocene on the basis of the testate amoeba and humification results. The macrocharcoal evidence indicates fire—probably in the surrounding forest—was relatively more common during the early Holocene, perhaps due to drier climate conditions. A large influx of charcoal at around 2000 cal yr BP suggests the presence of one or more major fires at this time, and a concurrent decrease in the rate of peat accumulation indicates the fire may have affected the bog itself. The data from Baltic Bog is broadly comparable to other proxy data (in particular pollen studies) from the Canadian Maritimes. This work is important because it: 1) helps us better understand the role of hydroclimatic variability in influencing peat bog ecosystems; and 2), represents one of the few peat-based records of Holocene paleoclimate from the region.

Tropical Hydroclimate Change during Heinrich Stadial 1: An Integrative Proxy-Model Synthesis

NASA Astrophysics Data System (ADS)

Lawman, A. E.; Sun, T.; Shanahan, T. M.; Di Nezio, P. N.; Gomez, K.; Piatrunia, N.; Sun, C.; Wu, X.; Kageyama, M.; Merkel, U.; Otto-Bliesner, B. L.; Abe-Ouchi, A.; Lohmann, G.; Singarayer, J. S.

2017-12-01

We explore the response of tropical climate to abrupt cooling of the North Atlantic (NA) during Heinrich Stadial 1 (HS1) combining paleoclimate proxies with model simulations. A total of 146 published paleoclimate records from tropical locations are used to categorize whether HS1 was wetter, drier, or unchanged relative to a deglacial baseline state. Only records with sufficient resolution to resolve HS1 and sufficient length to characterize the deglacial trend are considered. This synthesis reveals large-scale patterns of hydroclimate change relative to glacial conditions, confirming previously reported weaker Indian summer monsoon, a wetter southern Africa, and drying over the Caribbean. Our synthesis also reveals large-scale drying over the Maritime continent as well as wetter conditions in northern Australia and southern tropical South America. Our reinterpretation of the available proxy data reveals far more complexity and uncertainties for equatorial East Africa, a region that appears to straddle a pattern of dryer conditions to the north and wetter conditions to the south. Overall, these patterns of hydroclimate change depart from a southward shift of the Inter Tropical Convergence Zone (ITCZ), particularly outside the tropical Atlantic. We explore mechanisms driving these changes using a multi-model ensemble of "hosing" simulations performed relative to glacial conditions. The models show robust weakening of the Afro-Asian Monsoon, which we attribute to ventilation of colder mid-latitude air. Not all models simulate the remaining patterns inferred from the proxy data. The best-agreeing models indicate that cooling over the tropical NA and the Caribbean may be essential to communicate the response to the global tropics. This response can induce warming over the tropical South Atlantic via the wind-evaporation-SST feedback, driving wetter conditions in South Africa and tropical South America. Cooling over the Caribbean is communicated to the Pacific over the Central American isthmus resulting in an El Niño-like pattern accompanied by drying over the Maritime Continent - as seen in the proxy data. Together these results show a dominant role for altered tropical SST gradients driving changes in tropical rainfall, and a lesser role for inter-hemispheric shifts in the ITCZ.

The Last Interglacial-Glacial cycle (MIS 5-2) re-examined based on long proxy records from central and northern Europe

NASA Astrophysics Data System (ADS)

Helmens, Karin F.

2014-02-01

Current multi-proxy studies on a long sediment sequence preserved at Sokli (N Finland), i.e. in the central area of Fennoscandian glaciations, are drastically changing classic ideas of glaciations, vegetation and climate in northern Europe during the Late Pleistocene. The sediments in the Sokli basin have escaped major glacial erosion due to non-typical bedrock conditions. In this review, the Sokli record is compared in great detail with other long proxy records from central, temperate and northern, boreal Europe. These comprise the classic records of La Grande Pile (E France) and Oerel (N Germany) and more recently obtained records from Horoszki Duże (E Poland) and Lake Yamozero (NW Russia). The focus of the review is on pollen, lithology and macrofossil- and insect-based temperature inferences. The long records are further compared with recent proxy data from nearby terrestrial sites as well as with the rapidly accumulating high-resolution proxy data from the ocean realm. The comparison allows a re-examination of the environmental history and climate evolution of the Last Interglacial-Glacial (LI-G) cycle (MIS 5-2). It shows that environmental and climate conditions during MIS 5 (ca 130-70 ka BP) were distinctly different from those during MIS 4-2 (ca 70-15 ka BP). MIS 5 is characterized by three long forested intervals (broadly corresponding to MIS 5e, 5c, 5a), both in temperate and northern boreal Europe. These mild periods were interrupted by two short, relatively cold and dry intervals (MIS 5d and 5b) with mountain-centered glaciation in Fennoscandia. Millennial scale climate events were superimposed upon these longer lasting climate fluctuations. The time interval encompassing MIS 4-2 shows open vegetation. It is characterized by two glacial maxima (MIS 4 and 2) with sub-continental scale glaciation over northern Europe and dry conditions in strongly continental eastern European settings. High amplitude climate oscillations of millennial duration characterized the climate variability of MIS 3. Mild climate conditions in early MIS 3 caused large-scale deglaciation of the Fennoscandian Ice Sheet, and ice-free conditions with Betula-dominated vegetation (including tree birch) persisted over large parts of Fennoscandia, possibly interrupted by glaciation, during major part of MIS 3 till ca 35 ka BP. Overall, MIS 5 was mostly mild with warmest or peak interglacial conditions at the very start during MIS 5e. MIS 4-2 was mostly cold with most extreme or peak glacial conditions in the closing phase during MIS 2. This points to a subdivision of the last climate cycle into an early, overall mild interglacial half and a late, overall cold glacial half, each with duration of ca 50 ka. This review also shows that the climate variability in central and northern Europe during the LI-G cycle was mostly in degrees of continentality with major shifts in winter temperature and precipitation values; summer temperatures, on the other hand, remained largely unchanged. It points to the waxing and waning of sea-ice over the North Atlantic Ocean as a possible characteristic feature of the Late Pleistocene. The present compilation, based on long terrestrial sequences, high-resolution multi-proxy data from the oceans, and quantified paleo-climate data, strongly favors a definition of entire Marine Oxygen Isotope Stage 5 as the Last Interglacial similar as in the original marine stratigraphy and the stratigraphy at La Grande Pile in France. The proxy-based climate data places the start of the Last Glacial at the base of MIS 4 and the northwest European Pleniglacial. It shows that the division between the Eemian (MIS 5e) and the Early Weichselian (MIS 5d-a) is not useful, as not relevant from a climate point of view.

Opportunistic Feeding Strategy for the Earliest Old World Hypsodont Equids: Evidence from Stable Isotope and Dental Wear Proxies

PubMed Central

Tütken, Thomas; Kaiser, Thomas M.; Vennemann, Torsten; Merceron, Gildas

2013-01-01

Background The equid Hippotherium primigenium, with moderately hypsodont cheek teeth, rapidly dispersed through Eurasia in the early late Miocene. This dispersal of hipparions into the Old World represents a major faunal event during the Neogene. The reasons for this fast dispersal of H. primigenium within Europe are still unclear. Based on its hypsodonty, a high specialization in grazing is assumed although the feeding ecology of the earliest European hipparionines within a pure C3 plant ecosystem remains to be investigated. Methodology/Principal Findings A multi-proxy approach, combining carbon and oxygen isotopes from enamel as well as dental meso- and microwear analyses of cheek teeth, was used to characterize the diet of the earliest European H. primigenium populations from four early Late Miocene localities in Germany (Eppelsheim, Höwenegg), Switzerland (Charmoille), and France (Soblay). Enamel δ13C values indicate a pure C3 plant diet with small (<1.4‰) seasonal variations for all four H. primigenium populations. Dental wear and carbon isotope compositions are compatible with dietary differences. Except for the Höwenegg hipparionines, dental microwear data indicate a browse-dominated diet. By contrast, the tooth mesowear patterns of all populations range from low to high abrasion suggesting a wide spectrum of food resources. Conclusions/Significance Combined dental wear and stable isotope analysis enables refined palaeodietary reconstructions in C3 ecosystems. Different H. primigenium populations in Europe had a large spectrum of feeding habits with a high browsing component. The combination of specialized phenotypes such as hypsodont cheek teeth with a wide spectrum of diet illustrates a new example of the Liem’s paradox. This dietary flexibility associated with the capability to exploit abrasive food such as grasses probably contributed to the rapid dispersal of hipparionines from North America into Eurasia and the fast replacement of the brachydont equid Anchitherium by the hypsodont H. primigenium in Europe. PMID:24040254

Leaf wax records of late Holocene hydrologic changes on Abaco Island, Northern Bahamas

NASA Astrophysics Data System (ADS)

Tamalavage, A.; Feakins, S. J.; van Hengstum, P. J.; Louchouarn, P.; Fall, P. L.; Albury, N. A.; Donnelly, J. P.

2016-12-01

Previous pollen-based evidence from Abaco Island (Little Bahama Bank, Northern Bahamas) indicates that the terrestrial forest changed in dominance over the last 1500 years from palms to pines, and that this change is potentially driven by climate and/or anthropogenic factors. Geochemical markers (δ13Corg, δ15Norg,, C/N, and lignin phenols) measured from bulk sedimentary matter that has accumulated in Blackwood Sinkhole on Abaco Island also support the pollen-based evidence that vegetation has not been constant throughout the late Holocene (last 3000 years). More specifically, these geochemical markers document three intervals where sedimentary deposition was dominated by a different source of organic matter. These changes are likely driven by the combination of the ecological response to shoreline migration from Holocene sea-level rise, and a southward migration of the Intertropical Convergence Zone (ITCZ) at 1000 Cal yrs BP. However, the specific impact of a southward ITCZ displacement at 1000 Cal yrs BP on Abaco rainfall variability remains uncertain (e.g., quantity, seasonality). This research will explore hydrologic variability associated with regional vegetation changes by measuring precipitation isotopic composition based upon plant leaf wax n-alkanoic acid and n-alkane biomarkers. We find C29 and C31 n-alkanes and C24, C26, C28, and C30 n-alkanoic acids record the same hydrogen isotopic values within uncertainties indicating a uniform terrestrial vegetation source. We find a negative shift (-50‰) towards present in our initial analyses; the results of ongoing work will be presented at the meeting. This multi-proxy approach will allow us to resolve the nature of the leaf wax biomarker hydrogen isotope evidence for past precipitation, including testing for the impacts of vegetation on the hydrological proxy, and testing predictions of a shift in precipitation on Abaco Island over the late Holocene coincident with a southward displacement of the ITCZ.

Impact of the Little Ice Age cooling and 20th century climate change on peatland vegetation dynamics in central and northern Alberta using a multi-proxy approach and high-resolution peat chronologies

NASA Astrophysics Data System (ADS)

Magnan, Gabriel; van Bellen, Simon; Davies, Lauren; Froese, Duane; Garneau, Michelle; Mullan-Boudreau, Gillian; Zaccone, Claudio; Shotyk, William

2018-04-01

Northern boreal peatlands are major terrestrial sinks of organic carbon and these ecosystems, which are highly sensitive to human activities and climate change, act as sensitive archives of past environmental change at various timescales. This study aims at understanding how the climate changes of the last 1000 years have affected peatland vegetation dynamics in the boreal region of Alberta in western Canada. Peat cores were collected from five bogs in the Fort McMurray region (56-57° N), at the southern limit of sporadic permafrost, and two in central Alberta (53° N and 55° N) outside the present-day limit of permafrost peatlands. The past changes in vegetation communities were reconstructed using detailed plant macrofossil analyses combined with high-resolution peat chronologies (14C, atmospheric bomb-pulse 14C, 210Pb and cryptotephras). Peat humification proxies (C/N, H/C, bulk density) and records of pH and ash content were also used to improve the interpretation of climate-related vegetation changes. Our study shows important changes in peatland vegetation and physical and chemical peat properties during the Little Ice Age (LIA) cooling period mainly from around 1700 CE and the subsequent climate warming of the 20th century. In some bogs, the plant macrofossils have recorded periods of permafrost aggradation during the LIA with drier surface conditions, increased peat humification and high abundance of ericaceous shrubs and black spruce (Picea mariana). The subsequent permafrost thaw was characterized by a short-term shift towards wetter conditions (Sphagnum sect. Cuspidata) and a decline in Picea mariana. Finally, a shift to a dominance of Sphagnum sect. Acutifolia (mainly Sphagnum fuscum) occurred in all the bogs during the second half of the 20th century, indicating the establishment of dry ombrotrophic conditions under the recent warmer and drier climate conditions.

The Labrador Sea during the Last Glacial Maximum: Calcite dissolution or low biogenic carbonate fluxes?

NASA Astrophysics Data System (ADS)

Marshall, Nicole; de Vernal, Anne; Mucci, Alfonso; Filippova, Alexandra; Kienast, Markus

2017-04-01

Low concentrations of biogenic carbonate characterize the sediments deposited in the Labrador Sea during the last glaciation. This may reflect poor calcite preservation and/or low biogenic carbonate productivity and fluxes. Regional bottom water ventilation was reduced during the Last Glacial Maximum (LGM), so the calcite lysocline might have been shallower than at present in the deep Labrador Sea making dissolution of calcite shells in the deep Labrador Sea possible. To address the issue, a multi-proxy approach based on micropaleontological counts (coccoliths, foraminifers, palynomorphs) and biogeochemical analyses (alkenones) was applied in the investigation of core HU2008-029-004-PC recovered in the northwestern Labrador Sea. Calcite dissolution indices based on the relative abundance benthic foraminifera shells to their organic linings as well as on fragmentation of planktonic foraminifera shells were used to evaluate changes in calcite dissolution/ preservation since the LGM. In addition, the ratio of the concentrations of coccoliths, specifically of the alkenone-producer Emiliania huxleyi, and alkenones (Emiliania huxleyi: alkenones) was explored as a potential new proxy of calcite dissolution. A sharp increase in coccoliths, foraminifers and organic linings from nearly none to substantial concentrations at 12 ka, reflect a jump to significantly greater biogenic fluxes at the glacial-interglacial transition. Furthermore, conventional dissolution indices (shells/linings of benthic foraminifera and fragmentation of planktic foraminifers) reveal that dissolution is not likely responsible for the lower glacial abundances of coccoliths and foraminifers. Only the low Emiliania huxleyi: alkenones ratios in glacial sediments could be interpreted as evidence of increased dissolution during the LGM. Given the evidence of allochthonous alkenone input into the glacial Labrador Sea, the latter observations must be treated with caution. Overall, the records indicate that low biogenic fluxes during the LGM were the most likely cause of the decreased biogenic carbonate concentrations.

Aerosols Observations with a new lidar station in Punta Arenas, Chile

NASA Astrophysics Data System (ADS)

Barja, Boris; Zamorano, Felix; Ristori, Pablo; Otero, Lidia; Quel, Eduardo; Sugimoto, Nobuo; Shimizu, Atsushi; Santana, Jorge

2018-04-01

A tropospheric lidar system was installed in Punta Arenas, Chile (53.13°S, 70.88°W) in September 2016 under the collaboration project SAVERNET (Chile, Japan and Argentina) to monitor the atmosphere. Statistical analyses of the clouds and aerosols behavior and some cases of dust detected with lidar, at these high southern latitude and cold environment regions during three months (austral spring) are discussed using information from satellite, modelling and solar radiation ground measurements.

Alu elements in primates are preferentially lost from areas of high GC content

PubMed Central

Brookfield, John FY

2013-01-01

The currently-accepted dogma when analysing human Alu transposable elements is that ‘young’ Alu elements are found in low GC regions and ‘old’ Alus in high GC regions. The correlation between high GC regions and high gene frequency regions make this observation particularly difficult to explain. Although a number of studies have tackled the problem, no analysis has definitively explained the reason for this trend. These observations have been made by relying on the subfamily as a proxy for age of an element. In this study, we suggest that this is a misleading assumption and instead analyse the relationship between the taxonomic distribution of an individual element and its surrounding GC environment. An analysis of 103906 Alu elements across 6 human chromosomes was carried out, using the presence of orthologous Alu elements in other primate species as a proxy for age. We show that the previously-reported effect of GC content correlating with subfamily age is not reflected by the ages of the individual elements. Instead, elements are preferentially lost from areas of high GC content over time. The correlation between GC content and subfamily may be due to a change in insertion bias in the young subfamilies. The link between Alu subfamily age and GC region was made due to an over-simplification of the data and is incorrect. We suggest that use of subfamilies as a proxy for age is inappropriate and that the analysis of ortholog presence in other primate species provides a deeper insight into the data. PMID:23717800

Century-Long Warming Trends in the Upper Water Column of Lake Tanganyika

PubMed Central

Kraemer, Benjamin M.; Hook, Simon; Huttula, Timo; Kotilainen, Pekka; O’Reilly, Catherine M.; Peltonen, Anu; Plisnier, Pierre-Denis; Sarvala, Jouko; Tamatamah, Rashid; Vadeboncoeur, Yvonne; Wehrli, Bernhard; McIntyre, Peter B.

2015-01-01

Lake Tanganyika, the deepest and most voluminous lake in Africa, has warmed over the last century in response to climate change. Separate analyses of surface warming rates estimated from in situ instruments, satellites, and a paleolimnological temperature proxy (TEX86) disagree, leaving uncertainty about the thermal sensitivity of Lake Tanganyika to climate change. Here, we use a comprehensive database of in situ temperature data from the top 100 meters of the water column that span the lake’s seasonal range and lateral extent to demonstrate that long-term temperature trends in Lake Tanganyika depend strongly on depth, season, and latitude. The observed spatiotemporal variation in surface warming rates accounts for small differences between warming rate estimates from in situ instruments and satellite data. However, after accounting for spatiotemporal variation in temperature and warming rates, the TEX86 paleolimnological proxy yields lower surface temperatures (1.46 °C lower on average) and faster warming rates (by a factor of three) than in situ measurements. Based on the ecology of Thaumarchaeota (the microbes whose biomolecules are involved with generating the TEX86 proxy), we offer a reinterpretation of the TEX86 data from Lake Tanganyika as the temperature of the low-oxygen zone, rather than of the lake surface temperature as has been suggested previously. Our analyses provide a thorough accounting of spatiotemporal variation in warming rates, offering strong evidence that thermal and ecological shifts observed in this massive tropical lake over the last century are robust and in step with global climate change. PMID:26147964

Model for end-stage liver disease-based allocation system for liver transplantation in Argentina: does it work outside the United States?

PubMed

McCormack, L; Gadano, A; Lendoire, J; Imventarza, O; Andriani, O; Gil, O; Toselli, L; Bisigniano, L; de Santibañes, E

2010-09-01

In July 2005, Argentina was the first country after the United States to adopt the MELD system. The purpose of the present study was to analyse the impact of this new system on the adult liver waiting list (WL). Between 2005 and 2009, 1773 adult patients were listed for liver transplantation: 150 emergencies and 1623 electives. Elective patients were categorized using the MELD system. A prospective database was used to analyse mortality and probability to be transplanted (PTBT) on the WL. The waiting time increased inversely with the MELD score and PTBT positively correlated with MELD score. With scores >/= 18 the PTBT remained over 50%. However, the largest MELD subgroup with <10 points (n = 433) had the lower PTBT (3%). In contrast, patients with T(2) hepatocellular carcinoma benefited excessively with the highest PTBT (84.2%) and the lowest mortality rate (5.4%). The WL mortality increased after MELD adoption (10% vs. 14.8% vs. P < 0.01). Patients with <10 MELD points had >fourfold probability of dying on the WL than PTBT (14.3% vs. 3%; P < 0.0001). After MELD implementation, WL mortality increased and most patients who died had a low MELD score. A comprehensive revision of the MELD system must be performed to include cultural and socio-economical variables that could affect each country individually.

Evidence for male dispersal along the coasts but no migration in pelagic waters in dusky dolphins (Lagenorhynchus obscurus).

PubMed

Cassens, Insa; Van Waerebeek, Koen; Best, Peter B; Tzika, Athanasia; Van Helden, Anton L; Crespo, Enrique A; Milinkovitch, Michel C

2005-01-01

Using nine nuclear species-specific microsatellite loci and two mitochondrial gene fragments (cytochrome b and control region), we investigated the processes that have shaped the geographical distribution of genetic diversity exhibited by contemporary dusky dolphin (Lagenorhynchus obscurus) populations. A total of 221 individuals from four locations (Peru, Argentina, southern Africa, and New Zealand) were assayed, covering most of the species' distribution range. Although our analyses identify a general demographic decline in the Peruvian dusky dolphin stock (recently affected by high natural and human-induced mortality levels), comparison between the different molecular markers hint at an ancient bottleneck that predates recent El Niño oscillations and human exploitation. Moreover, we find evidence of a difference in dispersal behaviour of dusky dolphins along the South American coast and across the Atlantic. While data in Peruvian and Argentine waters are best explained by male-specific gene flow between these two populations, our analyses suggest that dusky dolphins from Argentina and southern Africa recently separated from an ancestral Atlantic population and, since then, diverged without considerable gene flow. The inclusion of a few New Zealand samples further confirms the low levels of genetic differentiation among most dusky dolphin populations. Only the Peruvian dusky dolphin stock is highly differentiated, especially at mitochondrial loci, suggesting that major fluctuations in its population size have led to an increased rate of genetic drift.

Spreading of hepatitis C virus subtypes 1a and 1b through the central region of Argentina.

PubMed

Culasso, Andrés Carlos Alberto; Farías, Adrián; Di Lello, Federico Alejandro; Golemba, Marcelo Darío; Ré, Viviana; Barbini, Luciana; Campos, Rodolfo

2014-08-01

The recent history of the hepatitis C virus (HCV) subtypes 1a and 1b in the central region of Argentina is hypothesized by phylogeographic reconstruction using coalescent based Bayesian analyses. Direct partial E2 sequences from HCV 1a and 1b infected patients attending different health-care centers of the country were analyzed. The inferred date of the most recent common ancestor (tMRCA) for HCV-1a was: 1962 (between 1943 and 1977) and for HCV-1b was earlier: 1929 (between 1895 and 1953). Diverse ancestral populations were inferred from both subtypes in Córdoba and in Buenos Aires cities and after that, HCV spread within and between larger cities and to other smaller cities. The analyses suggested that HCV-1b was dispersed first and it is currently in a stationary phase whereas HCV-1a was dispersed latter and it is still in a growth phase. Finally, as it was observed in the developed countries, while the transmission of HCV-1b appears to have been somehow prevented, the HCV-1a may still represent a concern in the public health. Further work should be carried out to address their current transmission rate (and its main transmission route) in the Argentinean population. Copyright © 2014 Elsevier B.V. All rights reserved.

The Beagle Channel Dispute between Argentina and Chile: An Historical Analysis

DTIC Science & Technology

1985-11-22

DTICr--1’ ’-’CTE~l THETSIS APPROVAL. TITLE OF THESIS: The Beagle Channel Dispute Between Argentina and Chile : An istorical Analysis " AME OF...85, subject: Security Review of Student Papers. 1. The enclosed thesis entitled "The Beagle Channel Dispute Between Argentina and Chile : An Historical...Title of Thesis: The Beagle Channel Dispute Between Argentina and Chile : An Historical Analysis David Robert Struthers, Master of Science in Strategic

Use of Smoking Cessation Interventions by Physicians in Argentina

PubMed Central

Schoj, Veronica; Mejia, Raul; Alderete, Mariela; Kaplan, Celia P.; Peña, Lorena; Gregorich, Steven E.; Alderete, Ethel; Pérez-Stable, Eliseo J.

2015-01-01

Background Physician-implemented interventions for smoking cessation are effective but infrequently used. We evaluated smoking cessation practices among physicians in Argentina. Methods A self-administered survey of physicians from six clinical systems asked about smoking cessation counselling practices, barriers to tobacco use counselling and perceived quality of training received in smoking cessation practices. Results Of 254 physicians, 52.3% were women, 11.8% were current smokers and 52% never smoked. Perceived quality of training in tobacco cessation counselling was rated as very good or good by 41.8% and as poor/very poor by 58.2%. Most physicians (90%) reported asking and recording smoking status, 89% advised patients to quit smoking but only 37% asked them to set a quit date and 44% prescribed medications. Multivariate analyses showed that Physicians’ perceived quality of their training in smoking cessation methods was associated with greater use of evidence-based cessation interventions. (OR = 6.5; 95% CI = 2.2–19.1); motivating patients to quit (OR: 7.9 CI 3.44–18.5), assisting patients to quit (OR = 9.9; 95% CI = 4.0–24.2) prescribing medications (OR = 9.6; 95% CI = 3.5–26.7), and setting up follow-up (OR = 13.0; 95% CI = 4.4–38.5). Conclusions Perceived quality of training in smoking cessation was associated with using evidence-based interventions and among physicians from Argentina. Medical training programs should enhance the quality of this curriculum. PMID:27594922

A time to be born: Variation in the hour of birth in a rural population of Northern Argentina.

PubMed

Chaney, Carlye; Goetz, Laura G; Valeggia, Claudia

2018-04-17

The present study aimed at investigating the timing of birth across the day in a rural population of indigenous and nonindigenous women in the province of Formosa, Argentina in order to explore the variation in patterns in a non-Western setting. This study utilized birth record data transcribed from delivery room records at a rural hospital in the province of Formosa, northern Argentina. The sample included data for Criollo, Wichí, and Toba/Qom women (n = 2421). Statistical analysis was conducted using directional statistics to identify a mean sample direction. Chi-square tests for homogeneity were also used to test for statistical significant differences between hours of the day. The mean sample direction was 81.04°, which equates to 5:24 AM when calculated as time on a 24-hr clock. Chi-squared analyses showed a statistically significant peak in births between 12:00 and 4:00 AM. Birth counts generally declined throughout the day until a statistically significant trough around 5:00 PM. This pattern may be associated with the circadian rhythms of hormone release, particularly melatonin, on a proximate level. At the ultimate level, giving birth in the early hours of the morning may have been selected to time births when the mother could benefit from the predator protection and support provided by her social group as well as increased mother-infant bonding from a more peaceful environment. © 2018 Wiley Periodicals, Inc.

"We talk of AIDS because we love life": a stakeholder assessment of HIV/AIDS organizations in Buenos Aires, Argentina.

PubMed

Spaulding, Alicen B; Brieger, William R

This stakeholder assessment of HIV/AIDS service providing institutions in Argentina offers insights into the HIV/AIDS crisis in Spanish-speaking Latin America from an institutional level and makes recommendations for strengthening the work and functioning of these institutions. This stakeholder assessment was conducted to determine how HIV/AIDS prevention and management in Argentina affects and is affected by relevant HIV/AIDS institutions. Semi-structured qualitative interviews were conducted with 13 key leaders of organizations working in HIV/AIDS prevention in Buenos Aires including non-governmental, governmental, and academic institutions. Analyses of interviewee comments are presented according to four major themes: network connections, program resources, perceptions of success, and challenges. Key findings include the need for strengthening formal networks, increasing the involvement of other non-AIDS related social institutions in promoting HIV prevention, finding more sustainable funding options, working more effectively with the public sector to create policies and regulations favorable to the HIV/AIDS field, and addressing the lack of perceived susceptibility to HIV/AIDS in Argentine culture. From leaders' comments, recommendations are made for strengthening the HIV/AIDS network among key institutions including adapting the UNAIDS "Three Ones" principal to create one crosssector office responsible for coordinating HIV/AIDS work, formalizing agreements with institutions outside of Buenos Aires, increasing the role of schools in HIV/AIDS awareness, and designing programs that address lack of perceived susceptibility to HIV/AIDS among Argentines.

Non-aflatoxigenic Aspergillus flavus as potential biocontrol agents to reduce aflatoxin contamination in peanuts harvested in Northern Argentina.

PubMed

Alaniz Zanon, María Silvina; Barros, Germán Gustavo; Chulze, Sofía Noemí

2016-08-16

Biological control is one of the most promising strategies for preventing aflatoxin contamination in peanuts at field stage. A population of 46 native Aspergillus flavus nonaflatoxin producers were analysed based on phenotypic, physiological and genetic characteristics. Thirty-three isolates were characterized as L strain morphotype, 3 isolates as S strain morphotype, and 10 isolates did not produce sclerotia. Only 11 of 46 non-aflatoxigenic isolates did not produce cyclopiazonic acid. The vegetative compatibility group (VCG) diversity index for the population was 0.37. For field trials we selected the non-aflatoxigenic A. flavus AR27, AR100G and AFCHG2 strains. The efficacy of single and mixed inocula as potential biocontrol agents in Northern Argentina was evaluated through a 2-year study (2014-2015). During the 2014 peanut growing season, most of the treatments reduced the incidence of aflatoxigenic strains in both soil and peanut kernel samples, and no aflatoxin was detected in kernels. During the 2015 growing season, there was a reduction of aflatoxigenic strains in kernel samples from the plots treated with the potential biocontrol agents. Reductions of aflatoxin contamination between 78.36% and 89.55% were observed in treated plots in comparison with the un-inoculated control plots. This study provides the first data on aflatoxin biocontrol based on competitive exclusion in the peanut growing region of Northern Argentina, and proposes bioproducts with potential use as biocontrol agents. Copyright © 2016. Published by Elsevier B.V.

Microbiological quality of Argentinian paprika.

PubMed

Melo González, María G; Romero, Stella M; Arjona, Mila; Larumbe, Ada G; Vaamonde, Graciela

The aim of this study was to evaluate the microbiological quality of paprika produced in Catamarca, Argentina. Microbiological analyses were carried out for the enumeration of total aerobic mesophilic bacteria, coliforms, yeasts and molds, and the detection of Salmonella in samples obtained from different local producers during three consecutive years. The mycobiota was identified paying special attention to the mycotoxigenic molds. Standard plate counts of aerobic mesophilic bacteria ranged from 2.7×10 5 to 3.7×10 7 CFU/g. Coliform counts ranged from <10 to 8.1×10 4 CFU/g. Salmonella was not detected in any of the samples tested. Fungal counts (including yeasts and molds) ranged between 2×10 2 and 1.9×10 5 CFU/g. These results showed a high level of microbial contamination, exceeding in several samples the maximum limits set in international food regulations. The study of the mycobiota demonstrated that Aspergillus was the predominant genus and Aspergillus niger (potential producer of ochratoxin A) the most frequently isolated species, followed by Aspergillus flavus (potential producer of aflatoxins). Other species of potential toxigenic fungi such as Aspergillus ochraceus, Aspergillus westerdijkiae, Penicillium chrysogenum, Penicillium crustosum, Penicillium commune, Penicillium expansum and Alternaria tenuissima species group were encountered as part of the mycobiota of the paprika samples indicating a risk of mycotoxin contamination. A. westerdijkiae was isolated for the first time in Argentina. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

[Epidemiology of caprine and ovine brucellosis in Formosa province, Argentina].

PubMed

Russo, Ana M; Mancebo, Orlando A; Monzón, Carlos M; Gait, Juan J; Casco, Rubén D; Torioni de Echaide, Susana M

2016-01-01

An epidemiological study of brucellosis was carried out in 516 goats and mixed flocks (goat/sheep) from the three agro-ecological regions of Formosa province, Argentina. Serum samples from a total of 25401 goats and 2453 sheeps were analyzed using buffered plate agglutination test (BPAT) and complement fixation test (CFT). Bacteriological and PCR analyses on milk samples from goats in three flocks with a history of brucellosis and recent abortions were also performed. Brucellosis was detected in four of the nine departments of the province with an overall prevalence of 2% and an intra-flock prevalence ranging between 1% and 40%. The proportion of infected flocks was 3.6%, 12% and 36% for the eastern, central and western regions, respectively. Brucella melitensis bv. 1 was isolated efrom goats for the first time in the province. The expected fragments of 827bp from the omp2ab gene (Brucella spp.) and 731bp from the insert IS711 (B. melitensis) were amplified by PCR. Detection of antibodies by BPAT and FCT in sheep cohabiting with goats suggests that infections could have been caused by B. melitensis, posing an additional risk to public health. Control and eradication programs for brucellosis should consider mixed flocks as a single epidemiological unit. The results indicate that brucellosis by B. melitensis bv1 is highly endemic in the central and western regions of Formosa province. Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Advantages of Task-Specific Multi-Objective Optimisation in Evolutionary Robotics

PubMed Central

Trianni, Vito; López-Ibáñez, Manuel

2015-01-01

The application of multi-objective optimisation to evolutionary robotics is receiving increasing attention. A survey of the literature reveals the different possibilities it offers to improve the automatic design of efficient and adaptive robotic systems, and points to the successful demonstrations available for both task-specific and task-agnostic approaches (i.e., with or without reference to the specific design problem to be tackled). However, the advantages of multi-objective approaches over single-objective ones have not been clearly spelled out and experimentally demonstrated. This paper fills this gap for task-specific approaches: starting from well-known results in multi-objective optimisation, we discuss how to tackle commonly recognised problems in evolutionary robotics. In particular, we show that multi-objective optimisation (i) allows evolving a more varied set of behaviours by exploring multiple trade-offs of the objectives to optimise, (ii) supports the evolution of the desired behaviour through the introduction of objectives as proxies, (iii) avoids the premature convergence to local optima possibly introduced by multi-component fitness functions, and (iv) solves the bootstrap problem exploiting ancillary objectives to guide evolution in the early phases. We present an experimental demonstration of these benefits in three different case studies: maze navigation in a single robot domain, flocking in a swarm robotics context, and a strictly collaborative task in collective robotics. PMID:26295151

Determinants of CO2 emissions in the MERCOSUR: the role of economic growth, and renewable and non-renewable energy.

PubMed

de Souza, Emerson Santana; Freire, Fátima de Souza; Pires, Josimar

2018-05-13

The main objective of this study was to analyze the impact of energy consumption (divided into renewable and non-renewable sources) and income on CO 2 emissions within the environmental Kuznets curve (EKC) model for the Southern Common Market (MERCOSUR). To do so, the annual panel data collected during the 1990-2014 periods was used. The CO 2 variable, representing carbon dioxide emissions in metric tons per capita, was used as a proxy for the emission of pollutants. The annual data were obtained from the World Bank (World Development Indicators). The sample consisted of the five MERCOSUR member countries: Argentina, Brazil, Paraguay, Uruguay, and Venezuela, comprising a period of 25 consecutive years. The results showed that energy consumption from renewable sources had a negative impact on CO 2 emissions, while the energy consumption from non-renewable sources had a positive impact. The positive impact of economic development on CO 2 emissions was also seen. In addition, this study supports the validity of the EKC hypothesis for the MERCOSUR because GDP (real output) leads to environmental degradation while GDP 2 reduces the level of gas emissions.

Predicting the spatial distribution of Ochlerotatus albifasciatus (Diptera: Culicidae) abundance with NOAA imagery.

PubMed

Gleiser, R M; Gorla, D E

2007-12-01

Ochlerotatus albifasciatus is a vector of western equine encephalomyelitis in Argentina and a nuisance mosquito affecting beef and dairy production. The objective of this study was to analyze whether environmental proxy data derived from 1 km resolution NOAA-AVHRR images could be useful as a rapid tool for locating areas with higher potential for Oc. albifasciatus activity at a regional scale. Training sites for mosquito abundance categories were 3.3x3.3 km polygons over sampling sites. Abundance was classified into two categories according to a proposed threshold for economic losses. Data of channels 1, 2, 4 and 5 were used to calculate five biophysical variables: normalized differences vegetation index (NDVI), land surface temperature, total precipitable water, dew point and vapour saturation deficit. A discriminant analysis correctly classified 100% of the areas predicted to be above or below the economic threshold of 2500 mosquitoes per night of capture, respectively. Components of the NDVI, the total precipitable water and the dew point temperature contributed most to the function value. The results suggest that environmental data derived from AVHRR-NOAA could be useful for rapidly identifying adequate areas for mosquito development or activity.

Milankovitch Cyclicity in the Eocene Green River Formation of Colorado and Wyoming

NASA Astrophysics Data System (ADS)

Machlus, M.; Olsen, P. E.; Christie-Blick, N.; Hemming, S. R.

2001-12-01

The Eocene Green River Formation is a classic example of cyclic lacustrine sediments. Following Bradley (1929, U.S.G.S. Prof. Paper 158-E), many descriptive studies suggested precession and eccentricity as the probable climatic forcing to produce the cyclic pattern. Here we report spectral analysis results that confirm this hypothesis. Furthermore, we have identified the presence of a surprisingly large amplitude obliquity cycle, the long-period eccentricity cycle (400 k.y.) and the long period modulators of obliquity. Spectral analyses of data from Colorado were undertaken on an outcrop section and core data using two different proxies for lake depth. In a section measured in the west Piceance Creek basin, three lithologies (ranks) were used as a proxy for relative water depth, from relatively shallow to deep water: laminated marlstones; microlaminated, light-colored oil-shales; and microlaminated black oil shales. A multi-tapered spectrum of the 190-m-thick record in the depth domain shows significant peaks at periods of 2.1, 3.4, 12 and 39 m. These are interpreted as the precession, obliquity and eccentricity cycles. The precession cycle confirms Bradley's independent estimate of 2.4 m per 20 k.y. cycle, based on varve counts at the same location. A high-amplitude, continuous 3.4 m (obliquity) cycle exists in the evolutive spectrum of this record. A second spectral analysis of an oil-shale-yield record was made on a 530 m core near the basin depocenter. This record includes the time-equivalent of the outcrop section, spans a longer interval of time, and has a higher sedimentation rate. Peaks are found at 5, 10, 25 and 79 m. Again, the probable obliquity peak, at 10 m, is continuous along the record. Initial tuning of this record to a 39.9 k.y. cosine wave improves the resolution of the precession, short and long eccentricity cycles. Spectral analysis of oil shale yield and sonic velocity data of cores from the Green River basin, Wyoming, gives similar results. Spectral peaks at 6, 13, 31 and 122 m appear mainly in the Tipton and the Wilkins Peak members. The correlation between oil shale yield, lithology and relative water depth was examined in the upper part of the Wilkins Peak Member and the Lower part of the Laney Member. The succession from microlaminated black oil shale to laminated micrite corresponds with documented lateral changes in facies from deep to shallow environments, thus confirming the use of these facies as relative water-depth proxies. Furthermore, the upsection record of oil shale yields correlates with these facies, with higher yields corresponding to deeper water facies. This correlation supports the use of the oil shale yield record as a proxy for short-term lake-level changes, and therefore a proxy for climate. The spectral analysis results from both basins show the importance of the obliquity cycle in these continental records. This cycle cannot be identified by cycle-counting, and therefore was not previously recognized. Earlier published attempts at spectral analysis of short records from the Piceance Creek and Uinta basins misinterpreted the observed cycles. This is the first time both the obliquity cycle and the long-term eccentricity cycle have been identified in the Green River and Piceance Creek basins.

The Ochodaeidae of Argentina (Coleoptera, Scarabaeoidea)

PubMed Central

Paulsen, M.J.; Ocampo, Federico C.

2012-01-01

Abstract The Ochodaeidae (Coleoptera: Scarabaeoidea) of Argentina are revised. Previously, two species of Ochodaeinae were known from the country, both in the genus Parochodaeus Nikolajev: Parochodaeus campsognathus (Arrow) and Parochodaeus cornutus (Ohaus). An additional 7 species of Parochodaeus from Argentina are described here as new. In addition, Gauchodaeus patagonicus, new genus and new species in the subfamilyChaetocanthinae, is described. This is the first record of the subfamily Chaetocanthinae in South America. Redescriptions, diagnoses, and maps are provided for each species. We also provide a key to genera and a key to species of Parochodaeus of Argentina. With this work, the number of ochodaeid species known from Argentina is increased from 2 to 10. PMID:22451781

Half-precessional climate forcing of Indian Ocean monsoon dynamics on the East African equator

NASA Astrophysics Data System (ADS)

Verschuren, D.; Sinninghe Damste, J. S.; Moernaut, J.; Kristen, I.; Fagot, M.; Blaauw, M.; Haug, G. H.; Project Members, C.

2008-12-01

The EuroCLIMATE project CHALLACEA produced a detailed multi-proxy reconstruction of the climate history of equatorial East Africa, based on the sediment record of Lake Challa, a 4.2 km2, 92-m deep crater lake on the lower East slope of Mt. Kilimanjaro (Kenya/Tanzania). Relatively stable sedimentation dynamics over the past 25,000 years resulted in a unique combination of high temporal resolution, excellent radiometric (210Pb, 14C) age control, and confidence that recording parameters of the climatic proxy signals extracted from the sediment have remained constant through time. The equatorial (3 deg. S) location of our study site in East Africa, where seasonal migration of convective activity spans the widest latitude range worldwide, produced unique information on how varying rainfall contributions from the northeasterly and southeasterly Indian Ocean monsoons shaped regional climate history. The Challa proxy records for temperature (TEX86) and moisture balance (reflection-seismic stratigraphy and the BIT index of soil bacterial input) uniquely weave together tropical climate variability at orbital and shorter time scales. The temporal pattern of reconstructed moisture balance bears the clear signature of half- precessional insolation forcing of Indian Ocean monsoon dynamics, modified by northern-latitude influence on moisture-balance variation at millennial and century time scales. During peak glacial time (but not immediately before) and the Younger Dryas, NH ice sheet influences overrode local insolation influence on monsoon intensity. After the NH ice sheets had melted and a relatively stable interglacial temperature regime developed, precession-driven summer insolation became the dominant determinant of regional moisture balance, with anti-phased patterns of Holocene hydrological change in the northern and southern (sub)tropics, and a uniquely hybrid pattern on the East African equator. In the last 2-3000 years a series of multi-century droughts with links to high latitude climate variability exerted widespread influence across the African continent. In northern and western tropical Africa these drought episodes accentuated the late- Holocene drying trend; in southern tropical Africa they mitigated or aborted the trend to increasing monsoon rainfall prescribed by SH insolation forcing.

Groundwater and Terrestrial Water Storage

NASA Technical Reports Server (NTRS)

Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

2012-01-01

Groundwater is a vital resource and also a dynamic component of the water cycle. Unconfined aquifer storage is less responsive to short term weather conditions than the near surface terrestrial water storage (TWS) components (soil moisture, surface water, and snow). However, save for the permanently frozen regions, it typically exhibits a larger range of variability over multi-annual periods than the other components. Groundwater is poorly monitored at the global scale, but terrestrial water storage (TWS) change data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission are a reasonable proxy for unconfined groundwater at climatic scales.

How do Durkheimian variables impact variation in national suicide rates when proxies for depression and alcoholism are controlled?

PubMed

Fernquist, Robert M

2007-01-01

Sociological research on Durkheim's theories of egoistic and anomic suicide has given Durkheim continued support more than a century after Durkheim published his work. Recent criticism by Breault (1994), though, argues that Durkheim's theories of suicide actually have not been empirically supported given the lack of psychological variables included in sociological research on suicide rates. Using proxy measures of depression and alcoholism, two known psychological variables to impact suicide, as well as classic Durkheimian variables, suicide rates in eight European countries from 1973-1997 were examined. Results indicate that Durkheim's theories of egoism and anomie, while not completely supported in statistical analysis of suicide rates, received moderate support. Results suggest the continued usefulness of Durkheim's work in aggregate analyses of suicide.

Argentina.

PubMed

1986-06-01

This discussion of Argentina covers geography, the people, history and political conditions, government, economy, foreign relations, and relations between the US and Argentina. In 1985, the population of Argentina was estimated to be 30.6 million with an estimated annual growth rate of 1.5%. The infant mortality rate is 34.1/1000, and life expectancy is 70.2 years. Argentina, which shares land borders with Bolivia, Brazil, Chile, Paraguay, and Uruguay, is bounded by the Atlantic and the Antarctic Oceans. Descendants of Italian and Spanish immigrants predominate in Argentina, but many trace their origins to British and West and East European ancestors. In recent years, there has been a substantial influx of immigrants from neighboring Latin American countries. The native Indian population, estimated to be 50,000, is concentrated in the peripheral provinces of the north, northwest, and south. What is now Argentina was discovered in 1516 by the Spanish navigator Juan de Solia. The formal declaration of independence from Spain was made on July 9, 1816. In the late 19th century, 2 forces worked to create the modern Argentine nation: the introduction of modern agricultural techniques and the integration of Argentina into the world economy. Argentina has impressive human and natural resources, but political conflict and uneven economic performance since World War II have impeded full realization of its considerable potential. Yet, it is one of the wealthiest countries in Latin America. Among the reasons for the military coup of March 1976 was the deteriorating economy, caused by declining production and rampant inflation. Under the leadership of the Minister of the Economy, the military government focused attention on those immediate problems, and, in 1978, embarked on a new development strategy focusing on the establishment of a free market economy. There was little improvement in the economy, and a new economic plan was introduced in 1985 which has capped inflation by introducing wage and price controls. Agricultural products constitute a major source of foreign exchange earnings. Argentina pursues a pragmatic, ideologically pluralistic foreign policy, maintaining relations with almost all countries. The US and Argentina have maintained diplomatic relations since 1823. Both countries have sought to maintain a harmonious, constructive relationship based on reciprocal respect and understanding.

Family factors in end-of-life decision-making: family conflict and proxy relationship.

PubMed

Parks, Susan Mockus; Winter, Laraine; Santana, Abbie J; Parker, Barbara; Diamond, James J; Rose, Molly; Myers, Ronald E

2011-02-01

Few studies have examined proxy decision-making regarding end-of-life treatment decisions. Proxy accuracy is defined as whether proxy treatment choices are consistent with the expressed wishes of their index elder. The purpose of this study was to examine proxy accuracy in relation to two family factors that may influence proxy accuracy: perceived family conflict and type of elder-proxy relationship. Telephone interviews with 202 community-dwelling elders and their proxy decision makers were conducted including the Life-Support Preferences Questionnaire (LSPQ), and a measure of family conflict, and sociodemographic characteristics, including type of relationship. Elder-proxy accuracy was associated with the type of elder-proxy relationship. Adult children demonstrated the lowest elder-proxy accuracy and spousal proxies the highest elder-proxy accuracy. Elder-proxy accuracy was associated with family conflict. Proxies reporting higher family conflict had lower elder-proxy accuracy. No interaction between family conflict and relationship type was revealed. Spousal proxies were more accurate in their substituted judgment than adult children, and proxies who perceive higher degree of family conflict tended to be less accurate than those with lower family conflict. Health care providers should be aware of these family factors when discussing advance care planning.

Structural setting of the Metán Basin (NW Argentina): new insights from 2D seismic profiles

NASA Astrophysics Data System (ADS)

Conti, Alessia; Maffucci, Roberta; Bigi, Sabina; Corrado, Sveva; Giordano, Guido; Viramonte, José G.

2017-04-01

The Metán Basin is located in the sub-Andean foreland, in the southernmost portion of the Santa Barbara system structural province (NW Argentina). The upper crust in this region shows a strong segmentation due to inherited stratigraphic and structural discontinuities, related to a Palaeozoic orogenic event and to a Cretaceous to Paleogene rifting event (Kley et al., 1999; Iaffa et al., 2011). This study seeks to unravel the deep structural setting of the basin, in order to better understand the tectonic evolution of the area. Different seismic sections are analysed, located in the Metán basin and acquired by YPF (Yacimientos Petrolíferos Fiscales, former national oil company of Argentina) in different surveys during the '70s - '80s. Stratigraphic control for the seismic interpretation is provided by petroleum exploratory wells drilled in the basin; they show a stratigraphic succession of syn-rift and post-rift deposits, mainly constituted by a continental succession of red beds, with minor limestone intercalations (Salta Group), overlain by a thick continental foreland basin succession (Orán Group) (Salfity et al., 1981). From a structural point of view, the Metán basin is characterized by a variety of structural trends, with thrust faults and related folds mainly trending N-S, NE-SW and NNE-SSW. Different mechanism can be responsible for the folding of the sedimentary cover; hangingwall anticlines are represented both by high angle thrust faults produced by inversion of Cretaceous extensional faults (Maffucci et al., 2015), and by fault propagation folds formed during the Andean shortening event. The study of the interaction between the older reactivated faults and the newly generated ones could provide new insights to unravel the complex structural setting of the area. References Iaffa D. N., Sàbat, F., Muñoz, J.A., Mon, R., Gutierrez, A.A., 2011. The role of inherited structures in a foreland basin evolution. The Metán Basin in NW Argentina. Journal of Structural Geology, 33, 1816-1828. Kley, J., Monaldi, C. R. & Salfity, J. A., 1999. Along strike segmentation of the Andean foreland: causes and consequences. Tectonophysics, 301, 75-94. Maffucci, R., Bigi, S., Corrado, S., Chiodi, A., Di Paolo, L., Giordano, G., Invernizzi, C., 2015. Quality assessment of reservoirs by means of outcrop data and "discrete fracture network" models: The case history of Rosario de La Frontera (NW Argentina) geothermal system. Tectonophysics, 647, 112-131. Salfity, J.A., Marquillas, R.A., 1981. Las unidades estratigráficas cretácicas del Norte de Argentina. In: Volkheimer, W., Musacchio, E. (Eds.), Cuencas Sedimentarias del Jurásico y Cretácico de América del Sur, 1, 303-317.

Argentina: Its Physical-Cultural Backgrounds and Implications for United States Foreign Policy

ERIC Educational Resources Information Center

Vent, Herbert J.

1974-01-01

This article provides a short history of political events in Argentina and a look at the people, geography, and economy of the country in order to consider current relations between Argentina and the United States. (JH)

Educational Decentralization Policies in Argentina and Brazil: Exploring the New Trends.

ERIC Educational Resources Information Center

Derqui, Jorge M. Gorostiaga

2001-01-01

Analyzes educational decentralization trends and policies in Argentina and Brazil during 1990s, includes case studies. Discusses historical background and rationales behind "provinicialization" in Argentina and "municipalization" in Brazil; identifies commonalities, including centralization of curriculum and evaluation…

Runoff and sediment yield from proxy records: Upper Animas Creek Basin, New Mexico

Treesearch

W. R. Osterkamp

1999-01-01

Analyses of water- and sediment-yield records from the Walnut Gulch Experimental Watershed, the San Simon Wash Basin, and the Jornada Experimental Range, combined with observations of regional variations in climate, geology and soils, vegetation, topography, fire frequency, and land-use history, allow estimates of present conditions of water and sediment discharges in...

Higher Education and Unemployment: A Cointegration and Causality Analysis of the Case of Turkey

ERIC Educational Resources Information Center

Erdem, Ekrem; Tugcu, Can Tansel

2012-01-01

This article analyses the short and the long-term relations between higher education and unemployment in Turkey for the period 1960-2007. It chooses the recently developed ARDL cointegration and Granger causality of Dolado and Lutkepohl (1996) methods. While the proxy of unemployment is total unemployment rate, higher education graduates were…

Relationships between Hong Kong Students' Perceptions of the Learning Environment and Their Learning Patterns in Post-Secondary Education

ERIC Educational Resources Information Center

Law, Dennis C. S.; Meyer, Jan H. F.

2011-01-01

The present study aims to analyse the complex relationships between the relevant constructs of students' demographic background, perceptions, learning patterns and (proxy measures of) learning outcomes in order to delineate the possible direct, indirect, or spurious effects among them. The analytical methodology is substantively framed against the…

Crush Analyses of Multi-Level Equipment

DOT National Transportation Integrated Search

2006-11-06

Non-linear large deformation crush analyses were conducted on a multi-level cab car typical of those in operation by the Southern California Regional Rail Authority (SCRRA) in California. The motivation for these analyses was a collision, which occur...

Effectiveness of Strict vs. Multiple Use Protected Areas in Reducing Tropical Forest Fires: A Global Analysis Using Matching Methods

PubMed Central

Nelson, Andrew; Chomitz, Kenneth M.

2011-01-01

Protected areas (PAs) cover a quarter of the tropical forest estate. Yet there is debate over the effectiveness of PAs in reducing deforestation, especially when local people have rights to use the forest. A key analytic problem is the likely placement of PAs on marginal lands with low pressure for deforestation, biasing comparisons between protected and unprotected areas. Using matching techniques to control for this bias, this paper analyzes the global tropical forest biome using forest fires as a high resolution proxy for deforestation; disaggregates impacts by remoteness, a proxy for deforestation pressure; and compares strictly protected vs. multiple use PAs vs indigenous areas. Fire activity was overlaid on a 1 km map of tropical forest extent in 2000; land use change was inferred for any point experiencing one or more fires. Sampled points in pre-2000 PAs were matched with randomly selected never-protected points in the same country. Matching criteria included distance to road network, distance to major cities, elevation and slope, and rainfall. In Latin America and Asia, strict PAs substantially reduced fire incidence, but multi-use PAs were even more effective. In Latin America, where there is data on indigenous areas, these areas reduce forest fire incidence by 16 percentage points, over two and a half times as much as naïve (unmatched) comparison with unprotected areas would suggest. In Africa, more recently established strict PAs appear to be effective, but multi-use tropical forest protected areas yield few sample points, and their impacts are not robustly estimated. These results suggest that forest protection can contribute both to biodiversity conservation and CO2 mitigation goals, with particular relevance to the REDD agenda. Encouragingly, indigenous areas and multi-use protected areas can help to accomplish these goals, suggesting some compatibility between global environmental goals and support for local livelihoods. PMID:21857950

A late Holocene record of solar-forced atmospheric blocking variability over Northern Europe inferred from varved lake sediments of Lake Kuninkaisenlampi

NASA Astrophysics Data System (ADS)

Saarni, Saija; Muschitiello, Francesco; Weege, Stefanie; Brauer, Achim; Saarinen, Timo

2016-12-01

This study presents a new varved lake sediment sequence from Lake Kuninkaisenlampi, Eastern Finland. The record is constituted by alternations of clastic and biogenic laminae and provides a precise chronology extending back to 3607 ± 94 varve yrs. BP. The seasonality of the boreal climatic zone, with cold winters and mild summers, is reflected in the varve structure as a succession of three laminae from bottom to top, (i) a coarse to fine-grained detrital lamina marked by detrital catchment material transported by spring floods; (ii) a biogenic lamina with diatoms, plant and insect remnants reflecting biological productivity during the season of lake productivity; and (iii) a very fine amorphous organic lamina deposited during the winter stratification. The thickness of the detrital lamina in the lake reflects changes in the rate of spring snow melt in the catchment and is, therefore, considered a proxy for winter conditions. Hence, the record allows reconstructing local climate and environmental conditions on inter-annual to the multi-centennial timescales. We find that minerogenic accumulation reflected in the detrital lamina exhibits a high multi-decadal to centennial-scale spectral coherency with proxies for solar activity, such as Δ14C, and Total Solar Irradiance, suggesting a strong link between solar variability and sediment transport to the lake basin. Increased catchment erosion is observed during periods of low solar activity, which we ascribe to the development of more frequent atmospheric winter blocking circulation induced by solar-forced changes in the stratosphere. We suggest that soil frost in the catchment of Lake Kuninkaisenlampi related to more frequent winter blocking led to increased surface run-off and ultimately to increased catchment erosion during spring. We conclude that, during the past ca 3600 years, solar forcing may have modulated multi-decadal to centennial variations in sedimentation regimes in lakes from Eastern Finland and potentially in other North European lakes.

Associations of the MCM6-rs3754686 proxy for milk intake in Mediterranean and American populations with cardiovascular biomarkers, disease and mortality: Mendelian randomization.

PubMed

Smith, Caren E; Coltell, Oscar; Sorlí, Jose V; Estruch, Ramón; Martínez-González, Miguel Ángel; Salas-Salvadó, Jordi; Fitó, Montserrat; Arós, Fernando; Dashti, Hassan S; Lai, Chao Q; Miró, Leticia; Serra-Majem, Lluís; Gómez-Gracia, Enrique; Fiol, Miquel; Ros, Emilio; Aslibekyan, Stella; Hidalgo, Bertha; Neuhouser, Marian L; Di, Chongzhi; Tucker, Katherine L; Arnett, Donna K; Ordovás, José M; Corella, Dolores

2016-09-14

Controversy persists on the association between dairy products, especially milk, and cardiovascular diseases (CVD). Genetic proxies may improve dairy intake estimations, and clarify diet-disease relationships through Mendelian randomization. We meta-analytically (n ≤ 20,089) evaluated associations between a lactase persistence (LP) SNP, the minichromosome maintenance complex component 6 (MCM6)-rs3754686C>T (nonpersistence>persistence), dairy intake, and CVD biomarkers in American (Hispanics, African-American and Whites) and Mediterranean populations. Moreover, we analyzed longitudinal associations with milk, CVD and mortality in PREDIMED), a randomized Mediterranean diet (MedDiet) intervention trial (n = 7185). The MCM6-rs3754686/MCM6-rs309180 (as proxy), LP-allele (T) was strongly associated with higher milk intake, but inconsistently associated with glucose and lipids, and not associated with CVD or total mortality in the whole population. Heterogeneity analyses suggested some sex-specific associations. The T-allele was associated with higher CVD and mortality risk in women but not in men (P-sex interaction:0.005 and 0.032, respectively), mainly in the MedDiet group. However, milk intake was not associated with CVD biomarkers, CVD or mortality either generally or in sub-groups. Although MCM6-rs3754686 is a good milk intake proxy in these populations, attributing its associations with CVD and mortality in Mediterranean women to milk is unwarranted, as other factors limiting the assumption of causality in Mendelian randomization may exist.

Tree-ring proxies of larch bud moth defoliation: latewood width and blue intensity are more precise than tree-ring width.

PubMed

Arbellay, Estelle; Jarvis, Ingrid; Chavardès, Raphaël D; Daniels, Lori D; Stoffel, Markus

2018-05-19

Reconstructions of defoliation by larch bud moth (LBM, Zeiraphera diniana Gn.) based on European larch (Larix decidua Mill.) tree rings have unraveled outbreak patterns over exceptional temporal and spatial scales. In this study, we conducted tree-ring analyses on 105 increment cores of European larch from the Valais Alps, Switzerland. The well-documented history of LBM outbreaks in Valais provided a solid baseline for evaluating the LBM defoliation signal in multiple tree-ring parameters. First, we used tree-ring width measurements along with regional records of LBM outbreaks to reconstruct the occurrence of these events at two sites within the Swiss Alps. Second, we measured earlywood width, latewood width and blue intensity, and compared these parameters with tree-ring width to assess the capacity of each proxy to detect LBM defoliation. A total of six LBM outbreaks were reconstructed for the two sites between AD 1850 and 2000. Growth suppression induced by LBM was, on average, highest in latewood width (59%), followed by total ring width (54%), earlywood width (51%) and blue intensity (26%). We show that latewood width and blue intensity can improve the temporal accuracy of LBM outbreak reconstructions, as both proxies systematically detected LBM defoliation in the first year it occurred, as well as the differentiation between defoliation and non-defoliation years. This study introduces blue intensity as a promising new proxy of insect defoliation and encourages its use in conjunction with latewood width.

On the properties of energy transfer in solar wind turbulence.

NASA Astrophysics Data System (ADS)

Sorriso-Valvo, Luca; Marino, Raffaele; Chen, Christopher H. K.; Wicks, Robert; Nigro, Giuseppina

2017-04-01

Spacecraft observations have shown that the solar wind plasma is heated during its expansion in the heliosphere. The necessary energy is made available at small scales by a turbulent cascade, although the nature of the heating processes is still debated. Because of the intermittent nature of turbulence, the small-scale energy is inhomogeneously distributed in space, resulting for example in the formation of highly localized current sheets and eddies. In order to understand the small-scale plasma processes occurring in the solar wind, the global and local properties of such energy distribution must be known. Here we study such properties using a proxy derived from the Von Karman-Howart relation for magnetohydrodynamics. The statistical properties of the energy transfer rate in the fluid range of scales are studied in detail using WIND spacecraft plasma and magnetic field measurements and discussed in the framework of the multifractal turbulent cascade. Dependence of the energy dissipation proxy on the solar wind conditions (speed, type, solar activity...) is analysed, and its evolution during solar wind expansion in the heliosphere is described using Helios II and Ulysses measurements. A comparison with other proxies, such as the PVI, is performed. Finally, the local singularity properties of the energy dissipation proxy are conditionally compared to the corresponding particle velocity distributions. This allows the identification of specific plasma features occurring near turbulent dissipation events, and could be used as enhanced mode trigger in future space missions.

Comment on “A critical evaluation of the boron isotope-pH proxy: The accuracy of ancient ocean pH estimates” by M. Pagani, D. Lemarchand, A. Spivack and J. Gaillardet

NASA Astrophysics Data System (ADS)

Hönisch, Bärbel; Hemming, N. Gary; Loose, Brice

2007-03-01

Pagani et al. [Pagani M., Lemarchand D., Spivack A., and Gaillardet J. (2005). A critical evaluation of the boron isotope-pH proxy: the accuracy of ancient ocean pH estimates. Geochim. Cosmochim. Acta69(4), 953-961] use data from previous boron isotope studies to suggest that the fractionation between boric acid and borate in seawater as well as the history of δ 11B in seawater are poorly understood, thus limiting our ability to capture realistic ocean pH with this proxy. Although we agree with the authors that the long recognized uncertainty in the secular variation of δ 11B seawater imposes a temporal limit on paleo-pH reconstructions, their evaluation of the δ 11B/pH relationship in carbonates is flawed. Potential complications from vital, temperature and dissolution effects reported in that paper are based on studies that are experimentally and/or analytically poorly constrained. Using published validation studies we will demonstrate that many of the problems outlined by Pagani et al. have already been addressed, or are based on misinterpretations of previous work. Most importantly, statistical evaluation suggests empirical data are best described by a fractionation of ˜20‰. Recent paleoreconstructions confirm that the boron isotope proxy can be used with confidence, if sample selection and analyses are done carefully.

Papers Selected for Presentation at the International Symposium on Remote Sensing of Environment (16th) Held at Buenos Aires, Argentina on 2-9 June 1982. Volume 1.

DTIC Science & Technology

1982-06-01

Subsurface Water Parameters Using Radiance Measurements from Space. POOP 022 Limnological Study of the Coastal Lagoon ’Coyuca de Benitez, Guerrero...unlimited. ORGANIZED BY Comisi6n Nacional de Investigaciones Espaciales Buenos Aires, Argentina Environmental Research Institute of Michigan Ann Arbor...Michigan, USA SPONSORED, IN PART, BY ARGENTINA Comando en Jefe de la Fuerza Aerea Argentina Secretarla de Planeamiento de la Presidencia de la Naci6n

Late glacial to Holocene water level and climate changes in the Gulf of Gemlik, Sea of Marmara: evidence from multi-proxy data

NASA Astrophysics Data System (ADS)

Filikci, Betül; Eriş, Kürşad Kadir; Çağatay, Namık; Sabuncu, Asen; Polonia, Alina

2017-10-01

Multi-proxy analyses of new piston core M13-08 together with seismic data from the Gulf of Gemlik provide a detailed record of paleoceanographic and paleoclimatic changes with special emphasis on the timing of the connections between the Sea of Marmara (SoM) and the Gulf of Gemlik during the late Pleistocene to Holocene. The deposition of a subaqueous delta sourced from the Armutlu River to the north is attributed to the lowstand lake level at -60 m in the gulf prior to 13.5 cal ka BP. On the basis of the seismic data, it is argued that the higher lake level (-60 m) in the gulf compared to the SoM level (-85 m) attests to its disconnection from the SoM during the late glacial period. Ponto-Caspian assemblages in the lacustrine sedimentary unit covering the time period between 13.5 and 12 cal ka BP represent a relict that was introduced into the gulf by a Black Sea outflow during the marine isotope stage 3 interstadial. Contrary to the findings of previous studies, the data suggest that such an outflow into the Gulf of Gemlik during the late glacial period could have occurred only if the SoM lake level (-85 m) was shallower than the sill depth (-55 m) of the gulf in the west. A robust age model of the core indicates the connection of the gulf with the marine SoM at 12 cal ka BP, consistent with the sill depth (-55 m) of the gulf on the global sea level curve. Strong evidence of a marine incursion into the gulf is well documented by the μ-XRF Sr/Ca data. The available profiles of elemental ratios in core M13-08, together with the age-depth model, imply that a warm and wet climate prevailed in the gulf during the early Holocene (12-10.1 cal ka BP), whereas the longest drought occurred during the middle Holocene (8.2-5.4 cal ka BP). The base of the main Holocene sapropel in the gulf is dated at 10.1 cal ka BP, i.e., 500 years younger than its equivalent in the SoM. The late Holocene is earmarked by warm and wet climate periods (5.0-4.2 and 4.2-2.7 cal ka BP) with some brief cold/dry periods (4.2 and 2.7-0.9 cal ka BP).

Ecological neighborhoods as a framework for umbrella species selection

USGS Publications Warehouse

Stuber, Erica F.; Fontaine, Joseph J.

2018-01-01

Umbrella species are typically chosen because they are expected to confer protection for other species assumed to have similar ecological requirements. Despite its popularity and substantial history, the value of the umbrella species concept has come into question because umbrella species chosen using heuristic methods, such as body or home range size, are not acting as adequate proxies for the metrics of interest: species richness or population abundance in a multi-species community for which protection is sought. How species associate with habitat across ecological scales has important implications for understanding population size and species richness, and therefore may be a better proxy for choosing an umbrella species. We determined the spatial scales of ecological neighborhoods important for predicting abundance of 8 potential umbrella species breeding in Nebraska using Bayesian latent indicator scale selection in N-mixture models accounting for imperfect detection. We compare the conservation value measured as collective avian abundance under different umbrella species selected following commonly used criteria and selected based on identifying spatial land cover characteristics within ecological neighborhoods that maximize collective abundance. Using traditional criteria to select an umbrella species resulted in sub-maximal expected collective abundance in 86% of cases compared to selecting an umbrella species based on land cover characteristics that maximized collective abundance directly. We conclude that directly assessing the expected quantitative outcomes, rather than ecological proxies, is likely the most efficient method to maximize the potential for conservation success under the umbrella species concept.

Multi-proxy reconstructions and the power of integration across marine, terrestrial, and freshwater ecosystems. (Invited)

NASA Astrophysics Data System (ADS)

Black, B.

2013-12-01

Over the past decade, dendrochronology (tree-ring analysis) techniques have been increasingly applied to growth increments of various bivalve, fish, and coral species. In particular, the use of crossdating ensures that all increments in a dataset have assigned the correct calendar year of formation and that the resulting chronology is exactly placed in time. Such temporal alignment facilitates direct comparisons among chronologies that span diverse taxa and ecosystems, illustrating the pervasive, synchronizing influence of climate from alpine forests to the continental slope. Such an approach can be particularly beneficial to reconstructions in that each species captures climate signals from its unique 'perspective' of life history and habitat. For example, combinations of tree-ring data and chronologies for the long-lived bivalve Pacific geoduck (Panopea generosa) capture substantially more variance in regional sea surface temperatures than either proxy could explain alone. Just as importantly, networks of chronologies spanning multiple trophic levels can help identify climate variables critical to ecosystem functioning, which can then be targeted to generate most biologically relevant reconstructions possible. Along the west coast of North America, fish and bivalve chronologies in combination with records of seabird reproductive success indicate that winter sea-level pressure is closely associated with California Current productivity, which can be hind-cast over the past six centuries using coastal tree-ring chronologies. Thus, multiple proxies not only increase reconstruction skill, but also help isolate climate variables most closely linked to ecosystem structure and functioning.

Multi-proxy reconstructions and the power of integration across marine, terrestrial, and freshwater ecosystems. (Invited)

NASA Astrophysics Data System (ADS)

Barrett, P. J.

2011-12-01

Over the past decade, dendrochronology (tree-ring analysis) techniques have been increasingly applied to growth increments of various bivalve, fish, and coral species. In particular, the use of crossdating ensures that all increments in a dataset have assigned the correct calendar year of formation and that the resulting chronology is exactly placed in time. Such temporal alignment facilitates direct comparisons among chronologies that span diverse taxa and ecosystems, illustrating the pervasive, synchronizing influence of climate from alpine forests to the continental slope. Such an approach can be particularly beneficial to reconstructions in that each species captures climate signals from its unique 'perspective' of life history and habitat. For example, combinations of tree-ring data and chronologies for the long-lived bivalve Pacific geoduck (Panopea generosa) capture substantially more variance in regional sea surface temperatures than either proxy could explain alone. Just as importantly, networks of chronologies spanning multiple trophic levels can help identify climate variables critical to ecosystem functioning, which can then be targeted to generate most biologically relevant reconstructions possible. Along the west coast of North America, fish and bivalve chronologies in combination with records of seabird reproductive success indicate that winter sea-level pressure is closely associated with California Current productivity, which can be hind-cast over the past six centuries using coastal tree-ring chronologies. Thus, multiple proxies not only increase reconstruction skill, but also help isolate climate variables most closely linked to ecosystem structure and functioning.

Lake ecosystem response to late Allerød climatic fluctuation (northern Poland)

NASA Astrophysics Data System (ADS)

Słowiński, Michał; Zawiska, Izabela; Ott, Florian; Noryśkiewicz, Agnieszka M.; Plessen, Birgit; Apolinarska, Karina; Lutyńska, Monika; Michczyńska, Danuta J.; Wulf, Sabine; Skubała, Piotr; Błaszkiewicz, Mirosław; Brauer, Achim

2014-05-01

The aim of this study is a better understanding, how local lake ecosystems responded to climate changes during the late Allerød - Younger Dryas transition. Therefore, we carried out a detailed high-resolution multi-proxy case study on the partly laminated sediments from the Trzechowskie palaeolake, located in the Pomeranian Lakeland, northern Poland (53°52'40"N, 18°12'93"E). We reconstructed the ecosystem response to climatic and environmental changes using biotic proxies (macrofossils, pollen, Cladocera, diatoms) and classical geochemical proxies (δ18O, δ13C, loss-on-ignition, CaCO3 content) in combination with high-resolution µ-XRF element core scanning. The core chronology has been established by biostratigraphy, AMS 14C-dating on plant macro remains, varve counting within the laminated intervals and the Laacher See Tephra (12880 varve yrs BP) as a precise isochrone. Framework of our investigation is a period covering 367 varve years of the late Allerød and the beginning of the Younger Dryas period where varve preservation gradually ceases. The pronounced changes at the late Allerød - Younger Dryas transition is well-reflected in all environmental indicators but with conspicuous leads and lags reflecting complex responses of lake ecosystems to climate variation. This study is a contribution to the Virtual Institute ICLEA (Integrated Climate and Landscape Evolution Analysis) funded by the Helmholtz Association. The research was supported by the National Science Centre Poland (grants No. NN 306085037 and NCN 2011/01/B/ST10/07367).

Testing the Deglacial Global Ocean Alkalization Hypothesis Using Foraminifer-based Mg/Ca, Shell Weight, and MFI

NASA Astrophysics Data System (ADS)

Ward, B. M.; Mekik, F.; Pourmand, A.

2015-12-01

In light of evidence for extensive modern ocean acidification, it has become imperative to better understand the global carbon cycle by reconstructing past ocean acidification/alkalization events. Our goal is to test the deglacial global alkalization hypothesis using a multi-proxy approach by reconstructing the pH, temperature, and [CO32-] of thermocline waters and the dissolution in deep sea sediments over the last 25,000 years in core ME-27 from the eastern equatorial Pacific. Our specific research questions are: Is there unequivocal evidence for a deglacial ocean alkalization event? If yes, what was the magnitude of the alkalization event? If no, how can we explain why evidence of this event is missing from our core? We inferred temperature from Mg/Ca, and habitat water [CO32-] from sized-normalized shell weight in Neogloboquadrina dutertrei. Dissolution in sediments was estimated using the Globorotalia menardii Fragmentation Index (MFI). We see no clear indication of a deglacial ocean alkalization event with our proxies. Neither our shell weight, nor MFI data show a more alkaline deglacial ocean compared to the Last Glacial Maximum and the modern Interglacial. Instead, we observe a steady decrease in thermocline [CO32-], and increase in deep sea calcite preservation since the LGM. Our results may indicate that the global alkalization event was obscured in ME-27 due to higher organic carbon fluxes during the deglacial, and/or due to yet undetermined effects of temperature on the foraminifer shell weight proxy.

Nuclear safeguards in Brazil and Argentina: 25 years of ABACC

NASA Astrophysics Data System (ADS)

Kassenova, Togzhan

2017-11-01

As possessors of advanced nuclear technology, Brazil and Argentina bear special responsibility for helping the international community and neighbors in their region feel confident that their nuclear programs are peaceful, secure, and safe. Over the past 25 years, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) has played an indispensable role in strengthening such confidence by implementing nuclear safeguards in the two countries. Today, ABACC carries out safeguards inspections at a total of 76 nuclear facilities in Brazil and Argentina. This article describes how Brazil and Argentina view trends in the global nonproliferation regime and international nuclear safeguards, and explains how these trends relate to unique challenges and opportunities facing Brazil, Argentina, and ABACC.

76 FR 29192 - Honey From Argentina: Final Results of Antidumping Duty Administrative Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-20

... Results of Antidumping Duty Administrative Review AGENCY: Import Administration, International Trade...) published its preliminary results of the 2008-2009 administrative review of the antidumping duty order on honey from Argentina. See Honey From Argentina: Preliminary Results of Antidumping Duty Administrative...

Falkland’s War: Strategic, Intelligence and Diplomatic Failures

DTIC Science & Technology

1985-05-01

Foreign and Commonwealth Office. Background Brief: Argentina Misinformation, July 1982. El Diario de Caracas. Special Edition: Las Malvinas. Mayo 1982...Daily Telegraph, 27 April 1982. • Aldo Ferrer. " Economia Argentina y estrategia preindustrial" in Alain Ronquie, ed.. Argentina hoy. Buenos Aires

Acculturation and bicultural efficacy effects on Chinese American immigrants' diabetes and health management.

PubMed

Chun, Kevin M; Kwan, Christine M L; Strycker, Lisa A; Chesla, Catherine A

2016-10-01

The primary goal of this study was to examine effects of bicultural efficacy, or perceived confidence in dealing with bicultural acculturation stressors, on type 2 diabetes management and health for first-generation, Cantonese-speaking, Chinese American immigrants (N = 162) recruited for a larger community-based diabetes intervention study (Chesla et al. in Res Nurs Health 36(4):359-372, 2013. doi: 10.1002/nur.21543 ). The current study also tested whether a new Bicultural Efficacy in Health Management (BEFF-HM) scale is a more robust predictor of diabetes and health outcomes than proxy (years in the U.S.) and general acculturation measures. Hierarchical regression analyses of cross-sectional data revealed that high BEFF-HM was significantly related to positive outcomes on five of six diabetes and health measures as hypothesized after accounting for participant characteristics, proxy and general acculturation measures, and social support. Proxy and general acculturation measures failed to predict any study outcome supporting our secondary hypothesis that BEFF-HM is a better predictor of Chinese American immigrants' diabetes and health management. An immigrant-focused research approach advances understanding of acculturation and bicultural efficacy effects on health by identifying key acculturation domains for study.

Results of the Simulation and Assimilation of Doppler Wind Lidar Observations in Preparation for European Space Agency's Aeolus Mission

NASA Technical Reports Server (NTRS)

McCarty, Will

2011-01-01

With the launch of the European Space Agency's Aeolus Mission in 2013, direct spaceborne measurements of vertical wind profiles are imminent via Doppler wind lidar technology. Part of the preparedness for such missions is the development of the proper data assimilation methodology for handling such observations. Since no heritage measurements exist in space, the Joint Observing System Simulation Experiment (Joint OSSE) framework has been utilized to generate a realistic proxy dataset as a precursor to flight. These data are being used for the development of the Gridpoint Statistical Interpolation (GSI) data assimilation system utilized at a number of centers through the United States including the Global Modeling and Assimilation Office (GMAO) at NASA/Goddard Space Flight Center and at the National Centers for Environmental Prediction (NOAA/NWS/NCEP) as an activity through the Joint Center for Satellite Data Assimilation. An update of this ongoing effort will be presented, including the methodology of proxy data generation, the limitations of the proxy data, the handling of line-of-sight wind measurements within the GSI, and the impact on both analyses and forecasts with the addition of the new data type.

Empirical analysis of storm-time energetic electron enhancements

NASA Astrophysics Data System (ADS)

O'Brien, Thomas Paul, III

This Ph.D. thesis documents a program for studying the appearance of energetic electrons in the Earth's outer radiation belts that is associated with many geomagnetic storms. The dynamic evolution of the electron radiation belts is an outstanding empirical problem in both theoretical space physics and its applied sibling, space weather. The project emphasizes the development of empirical tools and their use in testing several theoretical models of the energization of the electron belts. First, I develop the Statistical Asynchronous Regression technique to provide proxy electron fluxes throughout the parts of the radiation belts explored by geosynchronous and GPS spacecraft. Next, I show that a theoretical adiabatic model can relate the local time asymmetry of the proxy geosynchronous fluxes to the asymmetry of the geomagnetic field. Then, I perform a superposed epoch analysis on the proxy fluxes at local noon to identify magnetospheric and interplanetary precursors of relativistic electron enhancements. Finally, I use statistical and neural network phase space analyses to determine the hourly evolution of flux at a virtual stationary monitor. The dynamic equation quantitatively identifies the importance of different drivers of the electron belts. This project provides empirical constraints on theoretical models of electron acceleration.

Stability of biological father presence as a proxy for family stability: cross-racial associations with the longitudinal development of emotion regulation in toddlerhood.

PubMed

Bocknek, Erika London; Brophy-Herb, Holly E; Fitzgerald, Hiram E; Schiffman, Rachel F; Vogel, Cheri

2014-01-01

The current study, utilizing data from the National Early Head Start Research and Evaluation Project (Love et al., 2005) explored the relationship between biological father presence and emotion regulation over toddlerhood among children from low-income families. Conceptualizing biological father presence as a proxy for family role development, results are interpreted from a role development theoretical perspective. The latent growth curve model was compared based on child ethnoracial status (African American, Caucasian, Hispanic) and child gender. Consistent biological father presence was associated with toddlers' regulatory development across toddlerhood, and this relationship was most robust among Caucasian toddlers as compared to African American toddlers. Findings for Hispanic toddlers were not significantly different from those of Caucasian or African American families. Results bolster the literature on father presence and child outcomes. Analyses address consistency in father presence as a proxy for coherent role development and define a link between consistent father presence and children's regulatory development, demonstrating ethnoracial differences which are likely attributed to the social construction of family roles. © 2014 Michigan Association for Infant Mental Health.

A Study of Stranding of Juvenile Salmon by Ship Wakes Along the Lower Columbia River Using a Before-and-After Design: Before-Phase Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pearson, Walter H.; Skalski, J R.; Sobocinski, Kathryn L.

2006-02-01

Ship wakes produced by deep-draft vessels transiting the lower Columbia River have been observed to cause stranding of juvenile salmon. Proposed deepening of the Columbia River navigation channel has raised concerns about the potential impact of the deepening project on juvenile salmon stranding. The Portland District of the U.S. Army Corps of Engineers requested that the Pacific Northwest National Laboratory design and conduct a study to assess stranding impacts that may be associated with channel deepening. The basic study design was a multivariate analysis of covariance of field observations and measurements under a statistical design for a before and aftermore » impact comparison. We have summarized field activities and statistical analyses for the ?before? component of the study here. Stranding occurred at all three sampling sites and during all three sampling seasons (Summer 2004, Winter 2005, and Spring 2005), for a total of 46 stranding events during 126 observed vessel passages. The highest occurrence of stranding occurred at Barlow Point, WA, where 53% of the observed events resulted in stranding. Other sites included Sauvie Island, OR (37%) and County Line Park, WA (15%). To develop an appropriate impact assessment model that accounted for relevant covariates, regression analyses were conducted to determine the relationships between stranding probability and other factors. Nineteen independent variables were considered as potential factors affecting the incidence of juvenile salmon stranding, including tidal stage, tidal height, river flow, current velocity, ship type, ship direction, ship condition (loaded/unloaded), ship speed, ship size, and a proxy variable for ship kinetic energy. In addition to the ambient and ship characteristics listed above, site, season, and fish density were also considered. Although no single factor appears as the primary factor for stranding, statistical analyses of the covariates resulted in the following equations: (1) Stranding Probability {approx} Location + Kinetic Energy Proxy + Tidal Height + Salmonid Density + Kinetic energy proxy ? Tidal Height + Tidal Height x Salmonid Density. (2) Stranding Probability {approx} Location + Total Wave Distance + Salmonid Density Index. (3) Log(Total Wave Height) {approx} Ship Block + Tidal Height + Location + Ship Speed. (4) Log(Total Wave Excursion Across the Beach) {approx} Location + Kinetic Energy Proxy + Tidal Height The above equations form the basis for a conceptual model of the factors leading to salmon stranding. The equations also form the basis for an approach for assessing impacts of dredging under the before/after study design.« less

Pedogenic Magnetic Minerals in Soils: Some Tests of Current Models

NASA Astrophysics Data System (ADS)

Egli, R.

2008-12-01

The magnetic enhancement of soils is increasingly used as a proxy for continental climate, since it is related to the formation of pedogenic iron minerals under warm, humid conditions. Ultrafine magnetite is believed to be the major responsible of the magnetic enhancement, however, very little is known on the detailed formation mechanism, ant its relation to the soil iron cycle. Furthermore, the 'textbook' case of the Chinese Loess Plateau is not well replicated around the World: Loessic soils from the Midwestern US are systematically less enhanced than their Chinese counterpart under similar climatic conditions, and many loessic soils in Argentina are not enhanced at all. In trying to find a rationale behind these differences, I will address three main questions that need to be answered in a bottom-up approach to the problem. The first question is whether susceptibility is indeed controlled by fine magnetite, excluding any significant role of other minerals such as ferrihydrite, goethite, and hematite. This is a rock magnetic problem addressing the interpretation of magnetic measurements: is susceptibility an adequate proxy for the concentration of magnetic minerals in soils? Answering this question allows us to think directly in terms of abundance specific magnetic minerals, which is fundamental for any subsequent interpretation. The second question is directed to understanding the role of magnetic minerals in the soil iron cycle and how they are formed. This brings us to a discussion of the transfer function linking magnetic enhancement with climate. Is indeed rainfall the only parameter controlling pedogenesis? Why is rainfall apparently related with the logarithm of susceptibility in enhanced soils? Can we test current pedogenetic models against this empirical transfer function? The third question points to the role of parent material and later dust inputs. Midwestern US and Argentinian loesses are different from Chinese loess. Is this a reason for the differences observed in the magnetic enhancement of the respective soils? Enough material is now available to test current models and hypotheses with respect to the first two questions.

Combining charcoal sediment and molecular markers to infer a Holocene fire history in the Maya lowlands of Petén, Guatemala

NASA Astrophysics Data System (ADS)

Kirchgeorg, Torben; Schüpbach, Simon; Colombaroli, Daniele; Beffa, Giorgia; Radaelli, Marta; Kehrwald, Natalie; Barbante, Carlo

2015-04-01

Holocene vegetation changes in the Maya Lowlands during the Holocene are a result of changing climate conditions, solely anthropogenic activities, or interactions of both factors. As a consequence, it is difficult to assess how tropical ecosystems will cope with projected changes in precipitation and land-use intensification over the next decades. We investigated the role of fire during the Holocene by combining different proxies. We distinguished between three different morphotypes (grass, wood and leaves) in macroscopic charcoal. We also determined the molecular fire proxies levoglucosan, mannosan and galactosan. Combining these different fire proxies allows a more robust understanding of the complex history of fire regimes at different spatial scales during the Holocene. Comparing the two biomass burning proxies may help increase our understanding about advantages and limitations of molecular markers as proxies for past fire reconstruction in lake sediments. In order to infer changes in past biomass burning, we analysed a lake sediment core from Lake Petén Itzá, Guatemala (17°00'N, 89°50'W, 110 m above sea level), and compared our results with millennial-scale vegetation and climate change data available in this area. Some differences were observed between the two records and we assumed that while macroscopic charcoal represents a local fire signal, the molecular fire proxies records seem to be influenced by regional to supra-regional fire or low temperature fires. During the Holocene we detected three periods of high fire activity: 9500-6000 cal yr BP, 3800 cal yr BP and 2700 cal yr BP. We attributed the first maximum (9500-6000 cal yr BP) to only climate conditions, which corresponds with observations from previous studies in this region. The fast decrease in the relative abundance of woody charcoal to grass charcoal at the 3800 cal yr BP fire maximum may result from human activity, but we cannot exclude that this shift was related to climate conditions during this period. The last maximum (2700 cal yr BP) we attribute to the agricultural activity of the Maya at Lake Petén Itzá.

Boll weevil invasion process in Argentina

USDA-ARS?s Scientific Manuscript database

The boll weevil, Anthonomus grandis grandis Boheman, is the most destructive cotton pest in the Western Hemisphere. In 1993, the pest was reported in Argentina, and in 1994 boll weevils were captured in cotton fields in the Formosa Province on the border between Argentina and Paraguay. The pest ha...

Towards a New Cartography of Curriculum Reform: Reflections on Educational Decentralization in Argentina.

ERIC Educational Resources Information Center

Dussel, Ines; Tiramonti, Guillermina; Birgin, Alejandra

2000-01-01

States that educational reforms in Argentina have reshaped both school knowledge and institutional patterns of school administration. Analyzes the process of "curriculum reterritorialization" in Argentina, the contradictions and displacements it produces, and the hybrid products that result. Traces reterritorialization through four…

Model Sensitivity to North Atlantic Freshwater Forcing at 8.2 Ka

NASA Technical Reports Server (NTRS)

Morrill, Carrie; Legrande, Allegra Nicole; Renssen, H.; Bakker, P.; Otto-Bliesner, B. L.

2013-01-01

We compared four simulations of the 8.2 ka event to assess climate model sensitivity and skill in responding to North Atlantic freshwater perturbations. All of the simulations used the same freshwater forcing, 2.5 Sv for one year, applied to either the Hudson Bay (northeastern Canada) or Labrador Sea (between Canada's Labrador coast and Greenland). This freshwater pulse induced a decadal-mean slowdown of 10-25%in the Atlantic Meridional Overturning Circulation (AMOC) of the models and caused a large-scale pattern of climate anomalies that matched proxy evidence for cooling in the Northern Hemisphere and a southward shift of the Intertropical Convergence Zone. The multi-model ensemble generated temperature anomalies that were just half as large as those from quantitative proxy reconstructions, however. Also, the duration of AMOC and climate anomalies in three of the simulations was only several decades, significantly shorter than the duration of approx.150 yr in the paleoclimate record. Possible reasons for these discrepancies include incorrect representation of the early Holocene climate and ocean state in the North Atlantic and uncertainties in the freshwater forcing estimates.

Global Monsoon Change During the Last Glacial Maximum: A Multi-Model Study

NASA Astrophysics Data System (ADS)

Yan, M.; Wang, B.; Liu, J.

2016-12-01

Change of Global Monsoon (GM) during the Last Glacial Maximum (LGM) is investigated using results from the multi-model ensemble of 7 coupled climate models participated in the Coupled Model Intercomparison Project Phase 5 (CMIP5). The GM changes during LGM are identified by comparison of the results from the pre-industrial control run and the LGM run. The results show (1) The annual mean GM precipitation and GM domain are reduced by about 10% and 5%, respectively; (2) The monsoon intensity (demonstrated by the local summer-minus-winter precipitation) is also weakened over most monsoon regions except Australian monsoon; (3) The monsoon precipitation is reduced more during the local summer than winter; (4) Distinct from all other regional monsoons, the Australian monsoon is strengthened and the monsoon area is enlarged. Four major factors contribute to these changes. The lower greenhouse gas concentration and the presence of the ice sheets decrease air temperature and water vapor content, resulting in a general weakening of the GM precipitation and reduction of GM domain. The reduced hemispheric difference in seasonal variation of insolation may contribute to the weakened GM intensity. The changed land-ocean configuration in the vicinity of the Maritime Continent, along with the presence of the ice sheets and lower greenhouse gas concentration, result in strengthened land-ocean and North-South hemispheric thermal contrasts, leading to the unique strengthened Australian monsoon. Although some of the results are consistent with the proxy data, uncertainties remain in different models. More comparison is needed between proxy data and model experiments to better understand the changes of the GM during the LGM.

Functional traits of testate amoebae and multi-proxy data unveil exceptional Baltic bog ecohydrology, autogenic succession and climate change during the last 2000 years in CE Europe

NASA Astrophysics Data System (ADS)

Lamentowicz, Mariusz; Gałka, Mariusz; Tobolski, Kazimierz; Lamentowicz, Łukasz; Ersek, Vasile; Jassey, Vincent E. J.; van der Knaap, Willem O.

2017-04-01

We studied two peat cores from the Baltic raised bog (Mechacz Wielki in NE Poland). We aimed to separate signal of extrinsic and intrinsic forcing of the raised bog development using multi-proxy high-resolution approach. Using testate amoebae transfer function, we found that the bog revealed exceptionally stable hydrological conditions during the last 2k with a relatively high water table and lack of local fire events that allowed for rapid peat accumulation (2.75 mm/year) in the bog. Furthermore, the strong correlation between pH and community-weighted mean of testate amoeba traits suggests that other variables than water-table depth play a role in driving microbial properties under stable hydrological conditions. There is a difference in hydrological dynamics in bogs between NW and NE Poland until ca CE 1500, after which the water table reconstructions possess more similarities. Our data suggest a common regional climatic forcing in Mechacz Wielki, Gązwa and Kontolanrahka. Though it may still be too early to attempt a regional summary of wetness change in the southern Baltic region, this study is a next step to better understand the long-term peatland palaeohydrology in NE Europe. We suggest that extrinsic factors (climate) played an important role as a driver in mire development during the bog stage (AD 500-2012). Our results also show how various functional traits relate to different environmental variables in a range of trophic and hydrological scenarios on long time scales.

A multi-proxy record of hydroclimate, vegetation, fire, and post-settlement impacts for a subalpine plateau, Central Rocky Mountains U.S.A

USGS Publications Warehouse

Anderson, Lesleigh; Brunelle, Andrea; Thompson, Robert S.

2015-01-01

Apparent changes in vegetation distribution, fire, and other disturbance regimes throughout western North America have prompted investigations of the relative importance of human activities and climate change as potential causal mechanisms. Assessing the effects of Euro-American settlement is difficult because climate changes occur on multi-decadal to centennial time scales and require longer time perspectives than historic observations can provide. Here, we report vegetation and environmental changes over the past ~13,000 years as recorded in a sediment record from Bison Lake, a subalpine lake on a high plateau in northwestern Colorado. Results are based on multiple independent proxies, which include pollen, charcoal, and elemental geochemistry, and are compared with previously reported interpretations of hydroclimatic changes from oxygen isotope ratios. The pollen data indicate a slowly changing vegetation sequence from sagebrush steppe during the late glacial to coniferous forest through the late Holocene. The most dramatic vegetation changes of the Holocene occurred during the ‘Medieval Climate Anomaly’ (MCA) and ‘Little Ice Age’ (LIA) with rapid replacement of conifer forest by grassland followed by an equally rapid return to conifer forest. Late Holocene vegetation responses are mirrored by changes in fire, lake biological productivity, and watershed erosion. These combined records indicate that subsequent disturbance related to Euro-American settlement, although perhaps significant, had acted upon a landscape that was already responding to MCA-LIA hydroclimatic change. Results document both rapid and long-term subalpine grassland ecosystem dynamics driven by agents of change that can be anticipated in the future and simulated by ecosystem models.