Investigating genetic loci that encode plant-derived paleoclimate proxies

NASA Astrophysics Data System (ADS)

Bender, A. L. D.; Suess, M.; Chitwood, D. H.; Bradley, A. S.

2016-12-01

Long chain (>C25) n-alkanes in sediments predominantly derive from terrestrial plant waxes. Hydrogen isotope ratios (δD) of leaf wax hydrocarbons correlate with δDH2O of precipitation and are commonly used as paleoclimate proxies. However, biological variability in the isotopic fractionations between water and plant materials also affects the n-alkane δD values. Correct interpretation of this paleoclimate proxy requires that we resolve genetic and environmental effects. Genetic variability underlying differences in leaf wax structure and isotopic composition can be quantitatively determined through the use of model organisms. Interfertile Solanum sect. Lycopersicon (tomato) species provide an ideal model species complex for this approach. We used a set of 76 precisely defined near-isogenic lines (introgression lines [ILs]) in which small genomic regions from the wild tomato relative Solanum pennellii have been introduced into the genome of the domestic tomato, S. lycopersicum. By characterizing quantitative traits of these ILs (leaf wax structure and isotopic composition), we can resolve the degree to which each trait is regulated by genetic versus environmental factors. We present data from two growth experiments conducted with all 76 ILs. In this study, we quantify leaf wax traits, including δD values, δ13C values, and structural metrics including the methylation index (a variable that describes the ratio of iso­- and anteiso- to n-alkanes). Among ILs, δD values vary by up to 35‰ and 60‰ for C31 and C33 n-alkanes, respectively. Many ILs have methylation indices that are discernably different from the parent domesticated tomato (p < 0.001), which suggests that methylation is a highly polygenic trait. This pattern is similar to the genetics that control leaf shape, another trait commonly used as a paleoclimate proxy. Based on our preliminary analysis, we propose candidate genes that control aspects of plant physiology that affect these quantitative

Investigating the Influence of Vegetation Type on Modern Leaf Wax Hydrogen Isotopes from a High Latitude Ombrotrophic Bog to Inform Paleoclimate Interpretation

NASA Astrophysics Data System (ADS)

Balascio, N.; D'Andrea, W. J.; Anderson, R. S.

2016-12-01

Leaf wax hydrogen isotopes have been used to track changes in the isotopic composition of meteoric waters in a variety of locations. However, leaf wax compounds preserved in sedimentary environments reflect a mix of plant sources that can have a large range of molecular distributions and biosynthetic fractionation factors potentially complicating paleoclimate interpretations. Here we attempt to constrain the influence of vegetation type on leaf wax hydrogen isotope values at an ombrotrophic bog in northern Norway. We present: (i) δD values of n-alkanes from modern bog vegetation to establish the influence of vegetation type on n-alkane distributions and to provide a site-specific assessment of the biosynthetic isotopic fractionation, and (ii) δD values of n-alkanes from a sediment core spanning the last 10 ka where vegetation changes have been reconstructed based on pollen analysis. We found 14 different vegetation types growing on the bog surface that have average chain lengths from 25 to 30.5 and δD values of n-C25 to n-C33 ranging from -197‰ to -116‰. These samples also have a range of δD values among n-alkane homologues, from 1‰ to 33‰. Based on isotopic measurements of modern bog water, we calculate the average apparent fractionation of n-alkanes to be -108 ± 22‰. Sedimentary δD values of n-C25 to n-C33 over the last 10 ka range from -229 to -158‰ with distinct trends among mid- and long-chain length homologues. Changes in chain lengths and δD values, at times, correspond to vegetation shifts documented by pollen data, but also show unique trends that we interpret to represent variations in local precipitation isotopes related to past hydroclimate change.

The shaping of modern human immune systems by multiregional admixture with archaic humans.

PubMed

Abi-Rached, Laurent; Jobin, Matthew J; Kulkarni, Subhash; McWhinnie, Alasdair; Dalva, Klara; Gragert, Loren; Babrzadeh, Farbod; Gharizadeh, Baback; Luo, Ma; Plummer, Francis A; Kimani, Joshua; Carrington, Mary; Middleton, Derek; Rajalingam, Raja; Beksac, Meral; Marsh, Steven G E; Maiers, Martin; Guethlein, Lisbeth A; Tavoularis, Sofia; Little, Ann-Margaret; Green, Richard E; Norman, Paul J; Parham, Peter

2011-10-07

Whole genome comparisons identified introgression from archaic to modern humans. Our analysis of highly polymorphic human leukocyte antigen (HLA) class I, vital immune system components subject to strong balancing selection, shows how modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovans, a likely sister group to the Neandertals. Virtual genotyping of Denisovan and Neandertal genomes identified archaic HLA haplotypes carrying functionally distinctive alleles that have introgressed into modern Eurasian and Oceanian populations. These alleles, of which several encode unique or strong ligands for natural killer cell receptors, now represent more than half the HLA alleles of modern Eurasians and also appear to have been later introduced into Africans. Thus, adaptive introgression of archaic alleles has significantly shaped modern human immune systems.

The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans

PubMed Central

Abi-Rached, Laurent; Jobin, Matthew J; Kulkarni, Subhash; McWhinnie, Alasdair; Dalva, Klara; Gragert, Loren; Babrzadeh, Farbod; Gharizadeh, Baback; Luo, Ma; Plummer, Francis A; Kimani, Joshua; Carrington, Mary; Middleton, Derek; Rajalingam, Raja; Beksac, Meral; Marsh, Steven GE; Maiers, Martin; Guethlein, Lisbeth A; Tavoularis, Sofia; Little, Ann-Margaret; Green, Richard E; Norman, Paul J; Parham, Peter

2013-01-01

Whole genome comparisons identified introgression from archaic to modern humans. Our analysis of highly polymorphic HLA class I, vital immune system components subject to strong balancing selection, shows how modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovans, a likely sister group to the Neandertals. Virtual genotyping of Denisovan and Neandertal genomes identified archaic HLA haplotypes carrying functionally distinctive alleles that have introgressed into modern Eurasian and Oceanian populations. These alleles, of which several encode unique or strong ligands for natural killer cell receptors, now represent more than half the HLA alleles of modern Eurasians and also appear to have been later introduced into Africans. Thus, adaptive introgression of archaic alleles has significantly shaped modern human immune systems. PMID:21868630

Modern Climate Analogues of Late-Quaternary Paleoclimates for the Western United States.

NASA Astrophysics Data System (ADS)

Mock, Cary Jeffrey

This study examined spatial variations of modern and late-Quaternary climates for the western United States. Synoptic climatological analyses of the modern record identified the predominate climatic controls that normally produce the principal modes of spatial climatic variability. They also provided a modern standard to assess past climates. Maps of the month-to-month changes in 500 mb heights, sea-level pressure, temperature, and precipitation illustrated how different climatic controls govern the annual cycle of climatic response. The patterns of precipitation ratios, precipitation bar graphs, and the seasonal precipitation maximum provided additional insight into how different climatic controls influence spatial climatic variations. Synoptic-scale patterns from general circulation model (GCM) simulations or from analyses of climatic indices were used as the basis for finding modern climate analogues for 18 ka and 9 ka. Composite anomaly maps of atmospheric circulation, precipitation, and temperature were compared with effective moisture maps compiled from proxy data to infer how the patterns, which were evident from the proxy data, were generated. The analyses of the modern synoptic climatology indicate that smaller-scale climatic controls must be considered along with larger-scale ones in order to explain patterns of spatial climate heterogeneity. Climatic extremes indicate that changes in the spatial patterns of precipitation seasonality are the exception rather than the rule, reflecting the strong influence of smaller-scale controls. Modern climate analogues for both 18 ka and 9 ka clearly depict the dry Northwest/wet Southwest contrast that is suggested by GCM simulations and paleoclimatic evidence. 18 ka analogues also show the importance of smaller-scale climatic controls in explaining spatial climatic variation in the Northwest and northern Great Plains. 9 ka analogues provide climatological explanations for patterns of spatial heterogeneity over several

Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate Data, Climate Modeling, and Modern Observations that 2C Global Warming Could Be Dangerous

NASA Technical Reports Server (NTRS)

Hansen, J.; Sato, Makiko; Hearty, Paul; Ruedy, Reto; Kelley, Maxwell; Masson-Delmotte, Valerie; Russell, Gary; Tselioudis, George; Cao, Junji; Rignot, Eric;

The Shaping of Modern Hawaiian History: Databook and Atlas; Teacher Answer Book.

ERIC Educational Resources Information Center

Tamura, Eileen; And Others

This book is intended for use as a supplement to a five-unit instructional series, "The Shaping of Modern Hawaiian History." It presents information on land use, population and ethnic diversity, government, politics, the economy, and Hawaii's place in the Pacific. Provided are many graphs, tables, readings, documents, and maps, which…

Correspondence of terrestrial and marine paleoclimates, SW Florida, during Mid-Pliocene periods of global warmth

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

Willard, D.A.; Cronin, T.M.; Litwin, R.J.

Pollen and ostracode samples from shallow-marine strata of the Pinecrest Beds near Sarasota, FL were studied to compare terrestrial and marine paleoclimate records during periods of middle Pliocene global warmth. Pollen assemblages from strata deposited during sea-level highstands from about 3.5--3.0 Ma are dominated by Pinus pollen with subdominant Ouercus and common taxodiaceous pollen, which increases markedly in abundance near about 3.0 Ma. Comparison with modern, shallow-marine pollen assemblages from the east coast of the United States indicates that the 3.5--3.0 Ma vegetation was, overall, similar to vegetation from the southern third Florida. However, near 3.0 Ma, pollen assemblages becomemore » less similar to modern assemblages due to higher percentages of taxodiaceous pollen and lower percentages of herbaceous pollen. Such changes are consistent with warmer climates and, possibly, moister soil conditions. Marine ostracodes also show progressively higher percentages of thermophilic (subtropical/tropical) taxa and decreasing percentages of cryophilic (temperature) taxa between 3.5--3.0 Ma. From about 2.5--2.0 Ma, ostracode assemblages recorded open-bay, sometimes brackish environments similar to those in subtropical eastern North America today. The Pinecrest paleoclimate record shows (1) that during two periods of global warmth and high sea level, subtropical terrestrial and marine climates were not substantially warmer than today; (2) ocean and atmosphere temperatures probably were about the same as today, perhaps slightly higher during peak warmth near 3.0 Ma; (3) changes in pollen assemblages appear to lag behind changes in ostracode assemblages; (4) progressively warmer local climates 3.5--3.0 Ma probably record an increasing influence of warm Gulf Stream water as the Central American Isthmus closed.« less

Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous

NASA Astrophysics Data System (ADS)

Hansen, James; Sato, Makiko; Hearty, Paul; Ruedy, Reto; Kelley, Maxwell; Masson-Delmotte, Valerie; Russell, Gary; Tselioudis, George; Cao, Junji; Rignot, Eric; Velicogna, Isabella; Tormey, Blair; Donovan, Bailey; Kandiano, Evgeniya; von Schuckmann, Karina; Kharecha, Pushker; Legrande, Allegra N.; Bauer, Michael; Lo, Kwok-Wai

2016-03-01

We use numerical climate simulations, paleoclimate data, and modern observations to study the effect of growing ice melt from Antarctica and Greenland. Meltwater tends to stabilize the ocean column, inducing amplifying feedbacks that increase subsurface ocean warming and ice shelf melting. Cold meltwater and induced dynamical effects cause ocean surface cooling in the Southern Ocean and North Atlantic, thus increasing Earth's energy imbalance and heat flux into most of the global ocean's surface. Southern Ocean surface cooling, while lower latitudes are warming, increases precipitation on the Southern Ocean, increasing ocean stratification, slowing deepwater formation, and increasing ice sheet mass loss. These feedbacks make ice sheets in contact with the ocean vulnerable to accelerating disintegration. We hypothesize that ice mass loss from the most vulnerable ice, sufficient to raise sea level several meters, is better approximated as exponential than by a more linear response. Doubling times of 10, 20 or 40 years yield multi-meter sea level rise in about 50, 100 or 200 years. Recent ice melt doubling times are near the lower end of the 10-40-year range, but the record is too short to confirm the nature of the response. The feedbacks, including subsurface ocean warming, help explain paleoclimate data and point to a dominant Southern Ocean role in controlling atmospheric CO2, which in turn exercised tight control on global temperature and sea level. The millennial (500-2000-year) timescale of deep-ocean ventilation affects the timescale for natural CO2 change and thus the timescale for paleo-global climate, ice sheet, and sea level changes, but this paleo-millennial timescale should not be misinterpreted as the timescale for ice sheet response to a rapid, large, human-made climate forcing. These climate feedbacks aid interpretation of events late in the prior interglacial, when sea level rose to +6-9 m with evidence of extreme storms while Earth was less than 1 �

Triple Oxygen and Clumped Isotopes in Synthetic and Natural Carbonates: Implications for Paleoclimate and Paleohydrology Studies

NASA Astrophysics Data System (ADS)

Laskar, A. H.; Rangarajan, R.; Liang, M. C.

2016-12-01

Conventional oxygen isotope (δ18O) has widely been used for paleoclimate studies. However, multiple influencing factors such as temperature, precipitation and kinetic effects during carbonate precipitation complicate the interpretation of δ18O data sometimes. Triple oxygen isotope (Δ17O) in carbonates could be sensitive to kinetic effect occur during its precipitation in water. Carbonates may also record the Δ17O signature of the parent waters, providing a basis in the natural carbonates for identifying kinetic processes such as rapid degassing at lower relative humidity inside a cave during speleothem deposition. Clumped isotopes (Δ47) in carbonates give the formation temperatures of the carbonates if precipitated under isotopic equilibrium. The first goal of the study is to explore the applicability of Δ17O for paleohydrolocial studies. The second is to reconstruct paleotemperature with suitable natural carbonates using Δ47values. This is a rare paleoclimate study utilizing two sophisticated new tools. CO2 produced from carbonates by acid digestion was used for both Δ47 and Δ17O analysis. Purified CO2 samples were directly introduced into the Mass spectrometer (MAT 253) for clumped isotope analysis [1] and CO2-O2 exchange method in presence of platinum for Δ17O analysis [2,3]. We measured Δ47 and Δ17O values in synthetic carbonates precipitated at different temperatures (10-90 oC) and Δ17O values in the water from which the carbonate precipitated. We observed consistent Δ47 values in the carbonates while Δ17O were found to vary. Probably a proper slope (between δ18O and δ17O) selection for carbonates would give consistent results. We also measured Δ47 and Δ17O in modern and well dated speleothems from Chinese and Indian caves to study the paleohydrology and paleotemperature. Δ47 and Δ17O were also measured in modern natural carbonate depositions such as corals, foraminifer and marbles to explore their potentials for paleoclimate studies

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

Comparing Planning Hydrologic Ensembles associated with Paleoclimate, Projected Climate, and blended Climate Information Sets

NASA Astrophysics Data System (ADS)

Brekke, L. D.; Prairie, J.; Pruitt, T.; Rajagopalan, B.; Woodhouse, C.

2008-12-01

Water resources adaptation planning under climate change involves making assumptions about probabilistic water supply conditions, which are linked to a given climate context (e.g., instrument records, paleoclimate indicators, projected climate data, or blend of these). Methods have been demonstrated to associate water supply assumptions with any of these climate information types. Additionally, demonstrations have been offered that represent these information types in a scenario-rich (ensemble) planning framework, either via ensembles (e.g., survey of many climate projections) or stochastic modeling (e.g., based on instrument records or paleoclimate indicators). If the planning goal involves using a hydrologic ensemble that jointly reflects paleoclimate (e.g., lower- frequency variations) and projected climate information (e.g., monthly to annual trends), methods are required to guide how these information types might be translated into water supply assumptions. However, even if such a method exists, there is lack of understanding on how such a hydrologic ensemble might differ from ensembles developed relative to paleoclimate or projected climate information alone. This research explores two questions: (1) how might paleoclimate and projected climate information be blended into an planning hydrologic ensemble, and (2) how does a planning hydrologic ensemble differ when associated with the individual climate information types (i.e. instrumental records, paleoclimate, projected climate, or blend of the latter two). Case study basins include the Gunnison River Basin in Colorado and the Missouri River Basin above Toston in Montana. Presentation will highlight ensemble development methods by information type, and comparison of ensemble results.

Tales from the Paleoclimate Underground: Lessons Learned from Reconstructing Extreme Events

NASA Astrophysics Data System (ADS)

Frappier, A. E.

2017-12-01

Tracing patterns of paleoclimate extremes over the past two millennia is becoming ever more important in the effort to understand and predict costly weather hazards and their varied societal impacts. I present three paleoclimate vignettes from the past ten years of different paleotempestology projects I have worked on closely, illustrating our collective challenges and productive pathways in reconstructing rainfall extremes: temporal, spatial, and combining information from disparate proxies. Finally, I aim to share new results from modeling multiple extremes and hazards in Yucatan, a climate change hotspot.

Using Paleo-climate Comparisons to Constrain Future Projections in CMIP5

NASA Technical Reports Server (NTRS)

Schmidt, G. A.; Annan, J D.; Bartlein, P. J.; Cook, B. I.; Guilyardi, E.; Hargreaves, J. C.; Harrison, S. P.; Kageyama, M.; LeGrande, A. N..; Konecky, B.;

Constraining Lipid Biomarker Paleoclimate Proxies in a Small Arctic Watershed

NASA Astrophysics Data System (ADS)

Dion-Kirschner, H.; McFarlin, J. M.; Axford, Y.; Osburn, M. R.

2017-12-01

Arctic amplification of climate change renders high-latitude environments unusually sensitive to changes in climatic conditions (Serreze and Barry, 2011). Lipid biomarkers, and their hydrogen and carbon isotopic compositions, can yield valuable paleoclimatic and paleoecological information. However, many variables affect the production and preservation of lipids and their constituent isotopes, including precipitation, plant growth conditions, biosynthesis mechanisms, and sediment depositional processes (Sachse et al., 2012). These variables are particularly poorly constrained for high-latitude environments, where trees are sparse or not present, and plants grow under continuous summer light and cool temperatures during a short growing season. Here we present a source-to-sink study of a single watershed from the Kangerlussuaq region of southwest Greenland. Our analytes from in and around `Little Sugarloaf Lake' (LSL) include terrestrial and aquatic plants, plankton, modern lake water, surface sediments, and a sediment core. This diverse sample set allows us to fulfill three goals: 1) We evaluate the production of lipids and isotopic signatures in the modern watershed in comparison to modern climate. Our data exhibit genus-level trends in leaf wax production and isotopic composition, and help clarify the difference between terrestrial and aquatic signals. 2) We evaluate the surface sediment of LSL to determine how lipid biomarkers from the watershed are incorporated into sediments. We constrain the relative contributions of terrestrial plants, aquatic plants, and other aquatic organisms to the sediment in this watershed. 3) We apply this modern source-to-sink calibration to the analysis of a 65 cm sediment core record. Our core is organic-rich, and relatively high deposition rates allow us to reconstruct paleoenvironmental changes with high resolution. Our work will help determine the veracity of these common paleoclimate proxies, specifically for research in

Paleoclimate from fossil plants and application to the early Cenozoic Rocky Mountains

NASA Astrophysics Data System (ADS)

Wing, S. L.

2011-12-01

Wladimir Köppen called vegetation "crystallized, visible climate," and his metaphor encouraged paleobotanists to climb the chain of inference from fossil plants to paleovegetation to paleoclimate. Inferring paleovegetation from fossils has turned out to be very difficult, however, and today most paleobotanical methods for inferring paleoclimate do not try to reconstruct paleovegetation as a first step. Three major approaches are widely use to infer paleoclimate from plant fossils: 1) phylogenetic inferences rely on the climatic distributions of extant relatives of fossils, 2) morphological inferences use present-day correlations of climate with plant morphology (e.g, leaf shape, wood anatomy), and 3) chemical inferences rely on correlations between climate and the stable isotopic composition of plants or organic compounds. Each approach makes assumptions that are hard to verify. Phylogenetic inference depends on accurate identification of fossils, and also assumes that evolution and/or extinction has not shifted the climatic distributions of plant lineages through time. On average this assumption is less valid for older time periods, but probably it is not radically wrong for the early Cenozoic. Morphological approaches don't require taxonomic identification of plant fossils, but do assume that correlations between plant form and climate have been constant over time. This assumption is bolstered if the ecophysiological cause of the morphology-climate correlation is well understood, but often it isn't. Stable isotopic approaches assume that present-day correlations between isotopic composition and climate apply to the past. Commonly the chemical and physiological mechanisms responsible for the correlation are moderately well known, but often the variation among different taxonomic and functional groups of plants is poorly characterized. In spite of limitations and uncertainties on all methods for inferring paleoclimate from fossil plants, broad patterns emerge from

Pace of glacial retreat and limits on paleoclimate conditions for the Pine Creek Glacier, Montana, during the Pinedale Glaciation

NASA Astrophysics Data System (ADS)

Huss, E.; Laabs, B. J.; Leonard, E. M.; Licciardi, J. M.; Plummer, M. A.; Caffee, M. W.

2012-12-01

The timing of glaciation and the changes in climate that occurred both during and after the Last Glacial Maximum (LGM) in the Rocky Mountains are not well defined. Given the sensitivity of mountain glaciers to factors such as temperature, precipitation, and solar radiation, reconstructions of the history and extent of paleo-glaciers can be used to infer paleoclimate. Pine Creek Valley, located in the Absaroka Mountains in southwestern Montana, is an ideal setting for this type of research because it was occupied by a discrete valley glacier, the extent of which is precisely known during the LGM. To determine the pace and timing of ice retreat in this valley, glacially polished bedrock surfaces along the path of deglaciation were sampled at several points for cosmogenic 10Be surface exposure dating. The ages obtained range from 17.9 ± 0.8 to 13.2 ± 0.5 ka. When combined with the reconstructed ice extent during the LGM and subsequent deglaciation, these ages yield maximum and minimum retreat rates of 3.1 m/yr and 1.1 m/yr, respectively. These values constrain how long it took the glacier to retreat into a well-defined cirque from the terminal moraines. Paleoclimate conditions for the LGM were estimated using a two-dimensional, numerical, combined energy and mass balance and ice flow model. Previous qualitative inferences of paleoclimate in southern Montana indicate climate during the local LGM was colder and drier than modern values. If precipitation values were held constant or reduced for the Pine Creek glacier, the model suggests a temperature depression of at least 8°C.

Ancient geographical gaps and paleo-climate shape the phylogeography of an endemic bird in the sky islands of southern India.

PubMed

Robin, V V; Sinha, Anindya; Ramakrishnan, Uma

2010-10-13

Sky islands, formed by the highest reaches of mountain tracts physically isolated from one another, represent one of the biodiversity-rich regions of the world. Comparative studies of geographically isolated populations on such islands can provide valuable insights into the biogeography and evolution of species on these islands. The Western Ghats mountains of southern India form a sky island system, where the relationship between the island structure and the evolution of its species remains virtually unknown despite a few population genetic studies. We investigated how ancient geographic gaps and glacial cycles have partitioned genetic variation in modern populations of a threatened endemic bird, the White-bellied Shortwing Brachypteryx major, across the montane Shola forests on these islands and also inferred its evolutionary history. We used bayesian and maximum likelihood-based phylogenetic and population-genetic analyses on data from three mitochondrial markers and one nuclear marker (totally 2594 bp) obtained from 33 White-bellied Shortwing individuals across five islands. Genetic differentiation between populations of the species correlated with the locations of deep valleys in the Western Ghats but not with geographical distance between these populations. All populations revealed demographic histories consistent with population founding and expansion during the Last Glacial Maximum. Given the level of genetic differentiation north and south of the Palghat Gap, we suggest that these populations be considered two different taxonomic species. Our results show that the physiography and paleo-climate of this region historically resulted in multiple glacial refugia that may have subsequently driven the evolutionary history and current population structure of this bird. The first avian genetic study from this biodiversity hotspot, our results provide insights into processes that may have impacted the speciation and evolution of the endemic fauna of this region.

The Study of Beach Bar Shape Changes on Modern Coast by the Effect of Wind and Waves in Poyang Lake, South China

NASA Astrophysics Data System (ADS)

Hu, C.; Zhang, Y.; Jiang, Z.; Algeo, T. J.; Wang, M.; Lei, H.

2017-12-01

Poyang Lake formed along with the changing geological environment in the Quaternary as a continental faulted basin. Songmenshan Island lies within the lake and offers many examples of modern coastal deposits on its shore. There are plenty of typical modern coastal beach bar deposits and the plane shapes of beach bar are clearly visible at the Songmenshan Island shore in the center of the Poyang Lake. Modern coastal beach bar deposits are researched comprehensively in this article by geological surveying, research results of rhythm topography by Komar, wave model of littoral zone by Friedman and Sanders. The controlling factors of modern coastal beach bar sedimentary system and transformation relationships of different shapes beach bar are analyzed. The study shows that beach bar was divided into five microfacies based on the different shaped sand bodies of the modern coast. The waves, formed by the wind, are the main controlling factors of the modern coastal beach bar deposits based on the evidence of environment, climate and wind data in Poyang Lake. Among the 5 types of beach bar, 35 types of transformation relationship with different waves were identified. The modern coastal sedimentary model, which includes a beach bar influenced by waves and transformation relationships among the five kinds of beach bar, is representative of continental faulted lake basins.

Cenozoic climate change shaped the evolutionary ecophysiology of the Cupressaceae conifers

PubMed Central

Pittermann, Jarmila; Stuart, Stephanie A.; Dawson, Todd E.; Moreau, Astrid

2012-01-01

The Cupressaceae clade has the broadest diversity in habitat and morphology of any conifer family. This clade is characterized by highly divergent physiological strategies, with deciduous swamp-adapted genera-like Taxodium at one extreme, and evergreen desert genera-like Cupressus at the other. The size disparity within the Cupressaceae is equally impressive, with members ranging from 5-m-tall juniper shrubs to 100-m-tall redwood trees. Phylogenetic studies demonstrate that despite this variation, these taxa all share a single common ancestor; by extension, they also share a common ancestral habitat. Here, we use a common-garden approach to compare xylem and leaf-level physiology in this family. We then apply comparative phylogenetic methods to infer how Cenozoic climatic change shaped the morphological and physiological differences between modern-day members of the Cupressaceae. Our data show that drought-resistant crown clades (the Cupressoid and Callitroid clades) most likely evolved from drought-intolerant Mesozoic ancestors, and that this pattern is consistent with proposed shifts in post-Eocene paleoclimates. We also provide evidence that within the Cupressaceae, the evolution of drought-resistant xylem is coupled to increased carbon investment in xylem tissue, reduced xylem transport efficiency, and at the leaf level, reduced photosynthetic capacity. Phylogenetically based analyses suggest that the ancestors of the Cupressaceae were dependent upon moist habitats, and that drought-resistant physiology developed along with increasing habitat aridity from the Oligocene onward. We conclude that the modern biogeography of the Cupressaceae conifers was shaped in large part by their capacity to adapt to drought. PMID:22628565

Cenozoic climate change shaped the evolutionary ecophysiology of the Cupressaceae conifers.

PubMed

Pittermann, Jarmila; Stuart, Stephanie A; Dawson, Todd E; Moreau, Astrid

2012-06-12

The Cupressaceae clade has the broadest diversity in habitat and morphology of any conifer family. This clade is characterized by highly divergent physiological strategies, with deciduous swamp-adapted genera-like Taxodium at one extreme, and evergreen desert genera-like Cupressus at the other. The size disparity within the Cupressaceae is equally impressive, with members ranging from 5-m-tall juniper shrubs to 100-m-tall redwood trees. Phylogenetic studies demonstrate that despite this variation, these taxa all share a single common ancestor; by extension, they also share a common ancestral habitat. Here, we use a common-garden approach to compare xylem and leaf-level physiology in this family. We then apply comparative phylogenetic methods to infer how Cenozoic climatic change shaped the morphological and physiological differences between modern-day members of the Cupressaceae. Our data show that drought-resistant crown clades (the Cupressoid and Callitroid clades) most likely evolved from drought-intolerant Mesozoic ancestors, and that this pattern is consistent with proposed shifts in post-Eocene paleoclimates. We also provide evidence that within the Cupressaceae, the evolution of drought-resistant xylem is coupled to increased carbon investment in xylem tissue, reduced xylem transport efficiency, and at the leaf level, reduced photosynthetic capacity. Phylogenetically based analyses suggest that the ancestors of the Cupressaceae were dependent upon moist habitats, and that drought-resistant physiology developed along with increasing habitat aridity from the Oligocene onward. We conclude that the modern biogeography of the Cupressaceae conifers was shaped in large part by their capacity to adapt to drought.

Empirical Investigation of Critical Transitions in Paleoclimate

NASA Astrophysics Data System (ADS)

Loskutov, E. M.; Mukhin, D.; Gavrilov, A.; Feigin, A.

2016-12-01

In this work we apply a new empirical method for the analysis of complex spatially distributed systems to the analysis of paleoclimate data. The method consists of two general parts: (i) revealing the optimal phase-space variables and (ii) construction the empirical prognostic model by observed time series. The method of phase space variables construction based on the data decomposition into nonlinear dynamical modes which was successfully applied to global SST field and allowed clearly separate time scales and reveal climate shift in the observed data interval [1]. The second part, the Bayesian approach to optimal evolution operator reconstruction by time series is based on representation of evolution operator in the form of nonlinear stochastic function represented by artificial neural networks [2,3]. In this work we are focused on the investigation of critical transitions - the abrupt changes in climate dynamics - in match longer time scale process. It is well known that there were number of critical transitions on different time scales in the past. In this work, we demonstrate the first results of applying our empirical methods to analysis of paleoclimate variability. In particular, we discuss the possibility of detecting, identifying and prediction such critical transitions by means of nonlinear empirical modeling using the paleoclimate record time series. The study is supported by Government of Russian Federation (agreement #14.Z50.31.0033 with the Institute of Applied Physics of RAS). 1. Mukhin, D., Gavrilov, A., Feigin, A., Loskutov, E., & Kurths, J. (2015). Principal nonlinear dynamical modes of climate variability. Scientific Reports, 5, 15510. http://doi.org/10.1038/srep155102. Ya. I. Molkov, D. N. Mukhin, E. M. Loskutov, A.M. Feigin, (2012) : Random dynamical models from time series. Phys. Rev. E, Vol. 85, n.3.3. Mukhin, D., Kondrashov, D., Loskutov, E., Gavrilov, A., Feigin, A., & Ghil, M. (2015). Predicting Critical Transitions in ENSO models. Part II

Eocene Paleoclimate: Incredible or Uncredible? Model data syntheses raise questions.

NASA Astrophysics Data System (ADS)

Huber, M.

2012-04-01

Reconstructions of Eocene paleoclimate have pushed on the boundaries of climate dynamics theory for generations. While significant improvements in theory and models have brought them closer to the proxy data, the data themselves have shifted considerably. Tropical temperatures and greenhouse gas concentrations are now reconstructed to be higher than once thought--in agreement with models--but, many polar temperature reconstructions are even warmer than the eye popping numbers from only a decade ago. These interpretations of subtropical-to-tropical polar conditions once again challenge models and theory. But, the devil, is as always in the details and it is worthwhile to consider the range of potential uncertainties and biases in the paleoclimate record interpretations to evaluate the proposition that models and data may not materially disagree. It is necessary to ask whether current Eocene paleoclimate reconstructions are accurate enough to compellingly argue for a complete failure of climate models and theory. Careful consideration of Eocene model output and proxy data reveals that over most of the Earth the model agrees with the upper range of plausible tropical proxy data and the lower range of plausible high latitude proxy reconstructions. Implications for the sensitivity of global climate to greenhouse gas forcing are drawn for a range of potential Eocene climate scenarios ranging from a literal interpretation of one particular model to a literal interpretation of proxy data. Hope for a middle ground is found.

A modern plant-climate research dataset for modelling eastern North American plant taxa.

NASA Astrophysics Data System (ADS)

Gonzales, L. M.; Grimm, E. C.; Williams, J. W.; Nordheim, E. V.

2008-12-01

Continental-scale modern pollen-climate data repositories are a primary data source for paleoclimate reconstructions. However, these repositories can contain artifacts, such as records from different depositional environment and replicate records, that can influence the observed pollen-climate relationships as well as the paleoclimate reconstructions derived from these relationships. In this paper, we address the issues related to these artifacts as we define the methods used to create a research dataset from the North American Modern Pollen Database (Whitmore et al., 2005). Additionally, we define the methods used to select the environmental variables that are best for modeling regional pollen-climate relationships from the research dataset. Because the depositional environment determines the relative strengths of the local and regional pollen signals, combining data from different depositional environments results in pollen abundances that can be influenced by the local pollen signal. Replicate records in pollen-climate datasets can skew pollen-climate relationships by causing an over- or under- representation of pollen abundances in climate space. When these two artifacts are combined, the errors introduced into pollen-climate relationship modeling are compounded. The research dataset we present consists of 2,613 records in eastern North America, of which 70.9% are lacustrine sites. We demonstrate that this new research database improves upon the modeling of regional pollen-climate relationships for eastern North American taxa. The research dataset encompasses the majority of the temperature and mean summer precipitation ranges of the NAMPD's climatic range and 40% of its mean winter precipitation range. NAMPD sites with higher winter precipitation are located along the northwestern coast of North America where a rainshadow effect produces abundant winter precipitation. We present our analysis of the research dataset for use in paleoclimate reconstructions, and

Relating Paleoclimate Data and Past Temperature Gradients: Some Suggestive Rules

NASA Technical Reports Server (NTRS)

Rind, David

1999-01-01

Understanding tropical sensitivity is perhaps the major concern confronting researchers, for both past and future climate change issues. Tropical data has been beset by contradictions, and many techniques applicable to the extratropics are either unavailable or fraught with uncertainty when applied at low latitudes. Paleoclimate data, if interpreted within the context of the latitudinal temperature gradient data they imply, can be used to estimate what happened to tropical temperatures in the past, and provide a first guess for what might happen in the future. The approach is made possible by the modeling result that atmospheric dynamical changes, and the climate impacts they produce, respond primarily to temperature gradient changes. Here we review some "rules" obtained from GCM (General Circulation Model) experiments with different sea surface temperature gradients and different forcing, that can be used to relate paleoclimate reconstructions to the likely temperature gradient changes they suggest.

Reconstructing Late Holocene North Atlantic atmospheric circulation changes using functional paleoclimate networks

NASA Astrophysics Data System (ADS)

Franke, Jasper G.; Werner, Johannes P.; Donner, Reik V.

2017-11-01

Obtaining reliable reconstructions of long-term atmospheric circulation changes in the North Atlantic region presents a persistent challenge to contemporary paleoclimate research, which has been addressed by a multitude of recent studies. In order to contribute a novel methodological aspect to this active field, we apply here evolving functional network analysis, a recently developed tool for studying temporal changes of the spatial co-variability structure of the Earth's climate system, to a set of Late Holocene paleoclimate proxy records covering the last two millennia. The emerging patterns obtained by our analysis are related to long-term changes in the dominant mode of atmospheric circulation in the region, the North Atlantic Oscillation (NAO). By comparing the time-dependent inter-regional linkage structures of the obtained functional paleoclimate network representations to a recent multi-centennial NAO reconstruction, we identify co-variability between southern Greenland, Svalbard, and Fennoscandia as being indicative of a positive NAO phase, while connections from Greenland and Fennoscandia to central Europe are more pronounced during negative NAO phases. By drawing upon this correspondence, we use some key parameters of the evolving network structure to obtain a qualitative reconstruction of the NAO long-term variability over the entire Common Era (last 2000 years) using a linear regression model trained upon the existing shorter reconstruction.

Stratigraphic framework for Pliocene paleoclimate reconstruction: The correlation conundrum

USGS Publications Warehouse

Dowsett, H.J.; Robinson, M.M.

2006-01-01

Pre-Holocene paleoclimate reconstructions face a correlation conundrum because complications inherent in the stratigraphic record impede the development of synchronous reconstruction. The Pliocene Research, Interpretation and Synoptic Mapping (PRISM) paleoenvironmental reconstructions have carefully balanced temporal resolution and paleoclimate proxy data to achieve a useful and reliable product and are the most comprehensive pre-Pleistocene data sets available for analysis of warmer-than-present climate and for climate modeling experiments. This paper documents the stratigraphic framework for the mid-Pliocene sea surface temperature (SST) reconstruction of the North Atlantic and explores the relationship between stratigraphic/temporal resolution and various paleoceanographic estimates of SST. The magnetobiostratigraphic framework for the PRISM North Atlantic region is constructed from planktic foraminifer, calcareous nannofossil and paleomagnetic reversal events recorded in deep-sea cores and calibrated to age. Planktic foraminifer census data from multiple samples within the mid-Pliocene yield multiple SST estimates for each site. Extracting a single SST value at each site from multiple estimates, given the limitations of the material and stratigraphic resolution, is problematic but necessary for climate model experiments. The PRISM reconstruction, unprecedented in its integration of many different types of data at a focused stratigraphic interval, utilizes a time slab approach and is based on warm peak average temperatures. A greater understanding of the dynamics of the climate system and significant advances in models now mandate more precise, globally distributed yet temporally synchronous SST estimates than are available through averaging techniques. Regardless of the precision used to correlate between sequences within the midd-Pliocene, a truly synoptic reconstruction in the temporal sense is unlikely. SST estimates from multiple proxies promise to further

Shape of the piriform aperture in Gorilla gorilla, Pan troglodytes, and modern Homo sapiens: characterization and polymorphism analysis.

PubMed

Schmittbuhl, M; Le Minor, J M; Allenbach, B; Schaaf, A

1998-07-01

By using new methodologies based on automatic image analysis, the shape of the piriform aperture was analyzed in Gorilla gorilla (33 males, 13 females), Pan troglodytes (35 males, 22 females), and modern Homo sapiens (30 males, 12 females). The determination of the piriform aperture index (breadth/height) allowed the authors to demonstrate a marked elongation of the aperture in Homo compared with Gorilla and Pan. Individual characterization of the shape was possible with great precision and without ambiguity by using Fourier analysis. An absolute, interspecific partition between Gorilla, Pan, and Homo resulted from the canonical discriminant analysis of the Fourier descriptors. However, a closeness of shape between some individuals in Pan and some in Gorilla and Homo was observed, demonstrating a morphological continuum of the shape of the piriform aperture in hominoids: Pan was in intermediate position between Gorilla and Homo. Interspecific differences between Homo and the group Pan-Gorilla were explained principally by the differences in elongation (amplitude of the second harmonic) and pentagonality (amplitude of the fifth harmonic) and by differences in orientation of quadrangularity (phase of the fourth harmonic). Differences in the shape of the piriform aperture between Pan and Gorilla were explained by differences in orientation of elongation (phase of the second harmonic) and by differences in the component of triangularity (amplitude of the third harmonic). In Gorilla and Pan, the little, elongated, and relatively trapezoidal piriform aperture seems to be a shared primitive feature (plesiomorphic), whereas an elongated piriform aperture seems to be a characteristic and derived feature (apomorphic) of modern Homo sapiens.

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.

Assessing the risk persistent drought using climate model simulations and paleoclimate data

USGS Publications Warehouse

Ault, Toby R.; Cole, Julia E.; Overpeck, Jonathan T.; Pederson, Gregory T.; Meko, David M.

2014-01-01

Projected changes in global rainfall patterns will likely alter water supplies and ecosystems in semiarid regions during the coming century. Instrumental and paleoclimate data indicate that natural hydroclimate fluctuations tend to be more energetic at low (multidecadal to multicentury) than at high (interannual) frequencies. State-of-the-art global climate models do not capture this characteristic of hydroclimate variability, suggesting that the models underestimate the risk of future persistent droughts. Methods are developed here for assessing the risk of such events in the coming century using climate model projections as well as observational (paleoclimate) information. Where instrumental and paleoclimate data are reliable, these methods may provide a more complete view of prolonged drought risk. In the U.S. Southwest, for instance, state-of-the-art climate model projections suggest the risk of a decade-scale megadrought in the coming century is less than 50%; the analysis herein suggests that the risk is at least 80%, and may be higher than 90% in certain areas. The likelihood of longer-lived events (>35 yr) is between 20% and 50%, and the risk of an unprecedented 50-yr megadrought is nonnegligible under the most severe warming scenario (5%–10%). These findings are important to consider as adaptation and mitigation strategies are developed to cope with regional impacts of climate change, where population growth is high and multidecadal megadrought—worse than anything seen during the last 2000 years—would pose unprecedented challenges to water resources in the region.

Nano-structured calcite produced by micro-organisms in ancient and modern loess in Chinese Loess Plateau

NASA Astrophysics Data System (ADS)

Xu, H.; Chen, T.; Lu, H.; Wang, X.

2005-12-01

The results from transmission electron microscopy (TEM) and field emission gun scanning microscopy (FEG-SEM) investigation show that there are calcite nano-fibers (CNFs) formed during pedogenic process. The CNFs are widely distributed in the loess and red clay samples of Caoxian, Luochuan, Lingtai, Lantian, and Xifeng profiles as well as the samples of modern surface loess soils in Chinese Loess Plateau. Diameters of all the NFCs are about 40 nm, the length of the CNFs ranges from tens nanometer to several micrometers. Elongation direction of NFCs is unusual near parallel (105)* or (115)*. Crystals of NFCs arrange as bird net like and lattice-like frameworks. X-ray EDS spectra show the weak peaks of magnesium, phosphorous, and sulfur. Our investigation indicates that CNFs are in pore space of loess and paleosol and made up most of carbonate except for caliche nodular layers. Concentration of NFCs in the loess layers are significantly higher than those of paleosol layers because of leaching of carbonate in the paleosol forming environment (warn and wet paleoclimate). The "nanobacteria-like CNFs are well crystalline calcite single crystals with smoothes surfaces. The morphologies of CNFs are very unusual and different from the calcite single crystals observed in most geological environments. The CNFs are directly related to microbial activities in both ancient and modern loess. It is proposed that the intervention of organic compounds derived from microbial activities control the formation of the calcite nano-fibers. Both morphology and bulk composition of CNFs indicate that the formation of the CNFs involves bio-organics derived from microorganisms in loess deposit environment. Formation conditions of the calcite nano-fibers may information about paleoclimate, paleo-environment and paleoecology. So, the discovery of CNFs in loess-paloesol sequences can provide a new route for reconstruct paleoclimate by oxygen and carbon isotope from the CNFs.

The impact of using different modern climate data sets in pollen-based paleoclimate reconstructions of North America

NASA Astrophysics Data System (ADS)

Ladd, M.; Way, R. G.; Viau, A. E.

2015-03-01

The use of different modern climate data sets is shown to impact a continental-scale pollen-based reconstruction of mean July temperature (TJUL) over the last 2000 years for North America. Data from climate stations, physically modeled from climate stations and reanalysis products are used to calibrate the reconstructions. Results show that the use of reanalysis products produces warmer and/or smoother reconstructions as compared to the use of station based data sets. The reconstructions during the period of 1050-1550 CE are shown to be more variable because of a high latitude cold-bias in the modern TJUL data. The ultra-high resolution WorldClim gridded data may only useful if the modern pollen sites have at least the same spatial precision as the gridded dataset. Hence we justify the use of the lapse-rate corrected University of East Anglia Climate Research Unit (CRU) based Whitmore modern climate data set for North American pollen-based climate reconstructions.

Psycho-informatics: Big Data shaping modern psychometrics.

PubMed

Markowetz, Alexander; Błaszkiewicz, Konrad; Montag, Christian; Switala, Christina; Schlaepfer, Thomas E

2014-04-01

For the first time in history, it is possible to study human behavior on great scale and in fine detail simultaneously. Online services and ubiquitous computational devices, such as smartphones and modern cars, record our everyday activity. The resulting Big Data offers unprecedented opportunities for tracking and analyzing behavior. This paper hypothesizes the applicability and impact of Big Data technologies in the context of psychometrics both for research and clinical applications. It first outlines the state of the art, including the severe shortcomings with respect to quality and quantity of the resulting data. It then presents a technological vision, comprised of (i) numerous data sources such as mobile devices and sensors, (ii) a central data store, and (iii) an analytical platform, employing techniques from data mining and machine learning. To further illustrate the dramatic benefits of the proposed methodologies, the paper then outlines two current projects, logging and analyzing smartphone usage. One such study attempts to thereby quantify severity of major depression dynamically; the other investigates (mobile) Internet Addiction. Finally, the paper addresses some of the ethical issues inherent to Big Data technologies. In summary, the proposed approach is about to induce the single biggest methodological shift since the beginning of psychology or psychiatry. The resulting range of applications will dramatically shape the daily routines of researches and medical practitioners alike. Indeed, transferring techniques from computer science to psychiatry and psychology is about to establish Psycho-Informatics, an entire research direction of its own. Copyright © 2013 Elsevier Ltd. All rights reserved.

An Early Pleistocene high-resolution paleoclimate reconstruction from the West Turkana (Kenya) HSPDP drill site

NASA Astrophysics Data System (ADS)

Stockhecke, Mona; Beck, Catherine; Brown, Erik T.; Cohen, Andrew; Deocampo, Daniel M.; Feibel, Craig S.; Pelletier, Jon D.; Rabideaux, Nathane M.; Sier, Mark

2016-04-01

The Hominin Sites and Paleolakes Drilling Project (HSPDP), and the related Olorgesailie Drilling Project (ODP), recovered ~2 km of drill core since 2012. At the HSPDP West Turkana Kaitio (WTK) site a 216 m-long core that covers the Early Pleistocene time window (1.3 to 1.87 Ma) during which hominids first expanded out of Africa and marine records document reorganization of tropical climate and the development of the strong Walker circulation. WTK carries particular interest for paleoclimate and paleoenvironmental reconstructions as it is located only 2.5 km from the location of one of the most complete hominin skeletons ever recovered (Nariokotome Boy). XRF core scanning data provide a means of evaluating records of past environmental conditions continuously and at high resolution. However, the record contains complex lithologies reflecting repeated episodes of inundation and desiccation along a dynamic lake margin. Here we present a methodological approach to address the highly variable lithostratigraphy of the East African records to establish comprehensive paleoclimate timeseries. The power spectrum of the presented hydroclimate record peaks at Milankovitch cycles, qualifying HSPDP drill cores from the Turkana Basin to be used as high-resolution Early Pleistocene paleoclimate archive. Comparing these data with marine climate reconstructions sheds light into athmospheric processes and continental climate dynamics.

Paleoclimate and Paleoecology of Central Utah during the Past ≈200,000 Years from Soil Carbonate Pendants

NASA Astrophysics Data System (ADS)

Huth, T.; Cerling, T. E.; Fernandez, D. P.; Mackey, G. N., III; Bowling, D. R.; Marchetti, D. W.; Passey, B. H.

2016-12-01

Understanding the magnitude and duration of past climate events is essential to make accurate predictions about how global climate will vary over the next century. Quantitative paleoclimate records from arid regions are difficult to obtain, often present complex growth histories, and have poor chronologic dating relative to marine sediment archives. Pendants, which are several centimeter thick coatings of soil carbonate formed on the bottoms of boulders, represent a novel source for soil and climate records in arid areas. We developed two high resolution stable isotope paleorecords (C and O) from pendants collected in Utah at Torrey and the University of Utah Rio Mesa research station ≈200 km east of Torrey. The pendants are dense, finely laminated, and formed at >20 cm depth. They were dated by the cosmogenic 3He, U/Th, and radiocarbon methodologies. The pendants have nearly identical C isotope records with a roughly sinusoidal shape. The most negative values (-4‰ VPDB) occur during what we tentatively identify through radiocarbon dates as the Younger Dryas. Plants using the C4 photosynthetic pathway dominate through both records, as demonstrated by δ13C values of -4 to -1‰ (≈70-100% C4 plants). The consistency between these two records meets theoretical expectations that the sites, which sit at similar latitudes, should show similar changes in paleoecology and paleoclimate through time. The oxygen isotope record at Rio Mesa is dynamic and does not match the Torrey record. It ranges from -7 to -13‰ (VPDB) and shows a consistent increase towards the present. At 11 cal yr BP there is a 1.5‰ spike in the record. These patterns are in strong contrast to the Torrey record, which stays between -8 and -9‰ for the entirety of the record. The Torrey record can be reasonably explained through isotopic effects caused by factors like ocean temperature, glaciation extent, and temperature of calcite formation. However, these factors are inadequate to explain the

The Interfaces Between Historical, Paleo-, and Modern Climatology

NASA Astrophysics Data System (ADS)

Mock, C. J.

2011-12-01

Historical climatology, commonly defined as the study of reconstructing past climates from documentary and early instrumental data, has routinely utilized data within the last several hundred years down to sub-daily temporal resolution prior to the advent of "modern" instrumental records beginning in the late 19th and 20th centuries. Historical climate reconstruction methods generally share similar aspects conducted in both paleoclimate reconstruction and modern climatology, given the need to quantify, calibrate, and conduct careful data quality assessments. Although some studies have integrated historical climatic studies with other high resolution paleoclimatic proxies, very few efforts have integrated historical data with modern "systematic" climate networks to further examine spatial and temporal patterns of climate variability. This presentation describes historical climate examples of how such data can be integrated within modern climate timescales, including examples of documentary data on tropical cyclones from the Western Pacific and Atlantic Basins, colonial records from Belize and Constantinople, ship logbooks in the Western Arctic, plantation diaries from the American Southeast, and newspaper data from the Fiji Islands and Bermuda. Some results include a unique wet period in Belize and active tropical cyclone periods in the Western and South Pacific in the early 20th century - both are not reflected in conventional modern climate datasets. Documentary data examples demonstrate high feasibility in further understanding extreme weather events at daily timeframes such as false spring/killing frost episodes and hydrological extremes in southeastern North America. Recent unique efforts also involve community participation, secondary education, and web- based volunteer efforts to digitize and archive historical weather and climate information.

Sensitivity of leaf size and shape to climate: Global patterns and paleoclimatic applications

USGS Publications Warehouse

Peppe, D.J.; Royer, D.L.; Cariglino, B.; Oliver, S.Y.; Newman, S.; Leight, E.; Enikolopov, G.; Fernandez-Burgos, M.; Herrera, F.; Adams, J.M.; Correa, E.; Currano, E.D.; Erickson, J.M.; Hinojosa, L.F.; Hoganson, J.W.; Iglesias, A.; Jaramillo, C.A.; Johnson, K.R.; Jordan, G.J.; Kraft, N.J.B.; Lovelock, E.C.; Lusk, C.H.; Niinemets, U.; Penuelas, J.; Rapson, G.; Wing, S.L.; Wright, I.J.

2011-01-01

Paleobotanists have long used models based on leaf size and shape to reconstruct paleoclimate. However, most models incorporate a single variable or use traits that are not physiologically or functionally linked to climate, limiting their predictive power. Further, they often underestimate paleotemperature relative to other proxies. Here we quantify leaf-climate correlations from 92 globally distributed, climatically diverse sites, and explore potential confounding factors. Multiple linear regression models for mean annual temperature (MAT) and mean annual precipitation (MAP) are developed and applied to nine well-studied fossil floras. We find that leaves in cold climates typically have larger, more numerous teeth, and are more highly dissected. Leaf habit (deciduous vs evergreen), local water availability, and phylogenetic history all affect these relationships. Leaves in wet climates are larger and have fewer, smaller teeth. Our multivariate MAT and MAP models offer moderate improvements in precision over univariate approaches (??4.0 vs 4.8??C for MAT) and strong improvements in accuracy. For example, our provisional MAT estimates for most North American fossil floras are considerably warmer and in better agreement with independent paleoclimate evidence. Our study demonstrates that the inclusion of additional leaf traits that are functionally linked to climate improves paleoclimate reconstructions. This work also illustrates the need for better understanding of the impact of phylogeny and leaf habit on leaf-climate relationships. ?? 2011 The Authors. New Phytologist ?? 2011 New Phytologist Trust.

The Impact of the Geologic History and Paleoclimate on the Diversification of East African Cichlids

PubMed Central

Danley, Patrick D.; Husemann, Martin; Ding, Baoqing; DiPietro, Lyndsay M.; Beverly, Emily J.; Peppe, Daniel J.

2012-01-01

The cichlid fishes of the East African Great Lakes are the largest extant vertebrate radiation identified to date. These lakes and their surrounding waters support over 2,000 species of cichlid fish, many of which are descended from a single common ancestor within the past 10 Ma. The extraordinary East African cichlid diversity is intricately linked to the highly variable geologic and paleoclimatic history of this region. Greater than 10 Ma, the western arm of the East African rift system began to separate, thereby creating a series of rift basins that would come to contain several water bodies, including the extremely deep Lakes Tanganyika and Malawi. Uplifting associated with this rifting backponded many rivers and created the extremely large, but shallow Lake Victoria. Since their creation, the size, shape, and existence of these lakes have changed dramatically which has, in turn, significantly influenced the evolutionary history of the lakes' cichlids. This paper reviews the geologic history and paleoclimate of the East African Great Lakes and the impact of these forces on the region's endemic cichlid flocks. PMID:22888465

Patterns and timing of loess-paleosol transitions in Eurasia: Constraints for paleoclimate studies

NASA Astrophysics Data System (ADS)

Zeeden, Christian; Hambach, Ulrich; Obreht, Igor; Hao, Qingzhen; Abels, Hemmo A.; Veres, Daniel; Lehmkuhl, Frank; Gavrilov, Milivoj B.; Marković, Slobodan B.

2018-03-01

Loess-paleosol sequences are the most extensive terrestrial paleoclimate records in Europe and Asia documenting atmospheric circulation patterns, vegetation, and sedimentary dynamics in response to glacial-interglacial cyclicity. Between the two sides of the Eurasian continent, differences may exist in response and response times to glacial changes and finding these is essential to understand the climate systems of the northern hemisphere. Therefore, assessment of common patterns and regional differences in loess-paleosol sequences (LPS) is vital, but remains, however, uncertain. Another key to interpret these records is to constrain the mechanisms responsible for the formation and preservation of paleosols and loess layers in these paleoclimate archives. This study therefore compares LPS magnetic susceptibility records as proxies for paleosol formation intensity for selected sites from the central Chinese Loess Plateau and the Carpathian Basin in Europe over the last 440 kyr. Inconsistencies and crucial issues concerning the timing, correlation and paleoclimate potential of selected Eurasian LPS are outlined. Our comparison of Eurasian LPS shows generally similar patterns of paleosol formation, while highlighting several crucial differences. Especially for paleosols developed around 200 and 300 ka, the reported timing of soil formation differs by up to 30 ka. In addition, a drying and cooling trend over the last 300 ka has been documented in Europe, with no such evidence in the Asian records. The comparison shows that there is still uncertainty in defining the chronostratigraphic framework for these records on glacial-interglacial time scales in the order of 5-30 kyr for the last 440 ka. We argue that the baseline of the magnetic susceptibility proxy in loess from the Carpathian Basin is the most striking difference between European LPS and the Chinese Loess Plateau. In our opinion, many of the current timing/age differences may be overcome once a comparable

The impact of MIS-3 climate events at the transition from Neanderthals to modern humans in Europe

NASA Astrophysics Data System (ADS)

Staubwasser, M.; Dragusin, V.; Assonov, S.; Ersek, V.; Hoffmann, D.; Veres, D.; Onac, B. P.

2017-12-01

We report on last glacial stable C and O isotope records from two U-Th dated speleothems from Romania. The southerly record (Ascunsa Cave, South Carpathians) from the Danube region matches the pacing and relative change in amplitude of the Greenland ice temperature record at 30-50 ka BP as well as the abundance of coastal winter sea ice in the Black Sea. The northerly record (Tausoare Cave, East Carpathians) in parts shares the pacing of events with the Greenland or the southern Romanian record, but best matches northern Black Sea summer season temperature change. Heinrich events do not stand out in either record, but the temperature amplitudes of Greenland stadials and Black Sea records are generally reproduced. Based on similarity with the Black Sea we interpret the combined two speleothem records in terms of seasonal temperature change in central Eastern Europe. A climatic influence on the transition from Neanderthals to modern humans has long been suspected. However, the diachronous and spatially complex archaeologic succession across the Middle-Upper Paleolithic (MUPL) in Europe ( 38 - 48 ka) is difficult to reconcile with the millennial-scale pacing of northern hemisphere paleoclimate. Two extreme cold events at 44.0-43.3 recorded and 40.7-39.8 ka in the speleothems bracket the dates of the first known appearance of modern humans - the Aurignacian complex - and the disappearance of Neanderthals from most of Europe. These cold events are coeval with Greenland Stadials GS-12 and GS-10. The speleothem records generally match the paleosol/loess succession from central Europe across the MUPL. The combined record suggests that permafrost advance may have made central Europe uninhabitable at least during winter. The combined paleoclimate and archaeologic records suggest that depopulation-repopulation cycles may have occurred during and after each cold event. Repopulation of central Europe geographically favored the modern human Aurignacians from SE Europe.

Role of Seasonal Transitions and Westerly Jets in East Asian Paleoclimate

NASA Astrophysics Data System (ADS)

Chiang, J. C. H.; Fung, I. Y.; Wu, C. H.; Cai, Y.; Edman, J. P.; Liu, Y.; Day, J. A.; Bhattacharya, T.; Mondal, Y.; Labrousse, C.

2015-12-01

The summer rainfall climate of East Asia underwent large and abrupt changes during past climates. However, current interpretations of said changes are typically formulated in terms of modulation of summer monsoon intensity, and do not account for the known complexity in the seasonal evolution of East Asian rainfall, which exhibits sharp transition from the Spring regime to the Meiyu, and then again from the Meiyu to the Summer regime. We explore the interpretation that East Asian rainfall climate undergoes a modulation of its seasonality during said paleoclimate changes. Following previous suggestions we focus on role of the westerlies over Asia, that its latitude relative to Tibet is critical in determining the stepwise transitions in East Asian rainfall seasons. In support of this linkage, we show from observational data that the interannual co-variation of June (July-August) rainfall and upper tropospheric zonal winds show properties consistent with an altered timing of the transition to the Meiyu (Summer), and with more northward-shifted westerlies for earlier transitions. We similarly suggest that East Asian paleoclimate changes resulted from an altered timing in the northward evolution of the jet and hence the seasonal transitions, in particular the transition of the jet from south of the Plateau to the north. In an extreme scenario - which we speculate the climate system tended towards during stadial (cold) phases of D/O stadials and periods of low Northern Hemisphere summer insolation - the jet does not jump north of the Plateau, essentially keeping East Asia in prolonged Spring conditions. We argue that this hypothesis provides a viable explanation for a key paleoproxy signature of D/O stadials over East Asia, namely the heavier mean d18O of precipitation as recorded in speleothem records. The southward jet position prevents the low-level monsoonal flow - which is isotopically light - from penetrating into the interior of East Asia; as such, precipitation

Role of Seasonal Transitions and Westerly Jets in East Asian Paleoclimate

NASA Astrophysics Data System (ADS)

Chiang, J. C. H.; Fung, I. Y.; Wu, C. H.; Cai, Y.; Edman, J. P.; Liu, Y.; Day, J. A.; Bhattacharya, T.; Mondal, Y.; Labrousse, C.

2014-12-01

The summer rainfall climate of East Asia underwent large and abrupt changes in response to precessional forcing, glacial-interglacial cycles as well as abrupt changes to the North Atlantic during the last glacial. Current interpretations of said changes are typically formulated in terms of modulation of summer monsoon intensity, and do not account for the known complexity in the seasonal evolution of East Asian rainfall, which exhibits sharp transition from the Spring regime to the Meiyu, and then again from the Meiyu to the summertime. We explore the interpretation that East Asian rainfall climate undergoes a modulation of its seasonality during said paleoclimate changes. Following previous suggestions, we focus on role of the westerly jet: namely that the latitude of this westerly jet relative to Tibet is critical in determining the stepwise transitions in East Asian rainfall seasons. In support of this linkage, we show evidence from observational data for such a linkage in the timing of the Meiyu and Summer transitions, with more northward-shifted westerlies associated with earlier transitions. We similarly suggest that East Asian paleoclimate changes resulted from an altered timing in the northward evolution of the jet and hence the seasonal transitions, in particular the transition of the jet from south of the Plateau to the north that determines the seasonal transition from Spring rains to the Meiyu. In an extreme scenario - which we speculate the climate system tended towards during stadial (cold) phases of D/O stadials and periods of low Northern Hemisphere summer insolation - the jet does not jump north of the Plateau, essentially keeping East Asia in prolonged Spring conditions. We show that this hypothesis can explain a key paleoproxy signature of D/O stadials over East Asia, namely the heavier mean δ18O of precipitation as recorded in speleothem records. The southward jet position prevents the low-level monsoonal flow - which is isotopically light

A 507-year rainfall and runoff reconstruction for the Monsoonal North West, Australia derived from remote paleoclimate archives

NASA Astrophysics Data System (ADS)

Verdon-Kidd, Danielle C.; Hancock, Gregory R.; Lowry, John B.

2017-11-01

The Monsoonal North West (MNW) region of Australia faces a number of challenges adapting to anthropogenic climate change. These have the potential to impact on a range of industries, including agricultural, pastoral, mining and tourism. However future changes to rainfall regimes remain uncertain due to the inability of Global Climate Models to adequately capture the tropical weather/climate processes that are known to be important for this region. Compounding this is the brevity of the instrumental rainfall record for the MNW, which is unlikely to represent the full range of climatic variability. One avenue for addressing this issue (the focus of this paper) is to identify sources of paleoclimate information that can be used to reconstruct a plausible pre-instrumental rainfall history for the MNW. Adopting this approach we find that, even in the absence of local sources of paleoclimate data at a suitable temporal resolution, remote paleoclimate records can resolve 25% of the annual variability observed in the instrumental rainfall record. Importantly, the 507-year rainfall reconstruction developed using the remote proxies displays longer and more intense wet and dry periods than observed during the most recent 100 years. For example, the maximum number of consecutive years of below (above) average rainfall is 90% (40%) higher in the rainfall reconstruction than during the instrumental period. Further, implications for flood and drought risk are studied via a simple GR1A rainfall runoff model, which again highlights the likelihood of extremes greater than that observed in the limited instrumental record, consistent with previous paleoclimate studies elsewhere in Australia. Importantly, this research can assist in informing climate related risks to infrastructure, agriculture and mining, and the method can readily be applied to other regions in the MNW and beyond.

Objectively combining AR5 instrumental period and paleoclimate climate sensitivity evidence

NASA Astrophysics Data System (ADS)

Lewis, Nicholas; Grünwald, Peter

2018-03-01

Combining instrumental period evidence regarding equilibrium climate sensitivity with largely independent paleoclimate proxy evidence should enable a more constrained sensitivity estimate to be obtained. Previous, subjective Bayesian approaches involved selection of a prior probability distribution reflecting the investigators' beliefs about climate sensitivity. Here a recently developed approach employing two different statistical methods—objective Bayesian and frequentist likelihood-ratio—is used to combine instrumental period and paleoclimate evidence based on data presented and assessments made in the IPCC Fifth Assessment Report. Probabilistic estimates from each source of evidence are represented by posterior probability density functions (PDFs) of physically-appropriate form that can be uniquely factored into a likelihood function and a noninformative prior distribution. The three-parameter form is shown accurately to fit a wide range of estimated climate sensitivity PDFs. The likelihood functions relating to the probabilistic estimates from the two sources are multiplicatively combined and a prior is derived that is noninformative for inference from the combined evidence. A posterior PDF that incorporates the evidence from both sources is produced using a single-step approach, which avoids the order-dependency that would arise if Bayesian updating were used. Results are compared with an alternative approach using the frequentist signed root likelihood ratio method. Results from these two methods are effectively identical, and provide a 5-95% range for climate sensitivity of 1.1-4.05 K (median 1.87 K).

Sequence stratigraphy, paleoclimate, and tectonics of coal-bearing strata

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

Jack C. Pashin; Robert A. Gastaldo

2004-07-15

The origin of coal-bearing strata has been debated vigorously for more than a century, and with the emergence of coalbed methane as a major energy resource and the possibility of sequestering greenhouse gas in coal, this debate has never been more relevant. This volume contains 10 chapters on coal-bearing strata of Carboniferous through Tertiary age and is based on a special session that was held at an AAPG Annual Meeting in New Orleans. Contributors have employed a multitude of approaches ranging from basin analysis to plant taphonomy to support a variety of views on the sequence stratigraphy, paleoclimate, and tectonicsmore » of coal-bearing strata.« less

Connecting Paleo and Modern Oceanographic Data to Understand Atlantic Meridional Overturning Circulation Over Decades to Centuries

NASA Technical Reports Server (NTRS)

Kilbourne, Hali; Klockmann, Marlene; Moreno-Chamarro, Eduardo; Ortega, Pablo; Romanou, Anastasia; Srokosz, Meric; Szuts, Zoltan; Thirumalai, Kaustubh; Hall, Ian; Heimbach, Patrick;

Why Study Paleoclimate?

USGS Publications Warehouse

Robinson, Marci; Dowsett, Harry

2010-01-01

U.S. Geological Survey (USGS) researchers are at the forefront of paleoclimate research, the study of past climates. With their unique skills and perspective, only geologists have the tools necessary to delve into the distant past (long before instrumental records were collected) in order to better understand global environmental conditions that were very different from today's conditions. Paleoclimatologists are geologists who study past climates to answer questions about what the Earth was like in the past and to enable projections, plans, and preparations for the future. The Intergovernmental Panel on Climate Change (IPCC) has projected a future warmer climate that has the potential to affect every person on Earth. Extreme weather events, rising sea level, and migrating ecosystems and resources could result in worldwide socio-economic stresses if not met with prudent and proactive action plans based on quality scientific research. Still, the most dangerous aspect of our changing climate is the uncertainty in the exact nature and rate of projected climate change. To reduce the uncertainties, USGS paleoclimatologists are studying a possible analog to a future warmer climate. The middle part of the Piacenzian Stage of the Pliocene Epoch, about 3.3 to 3.0 million years ago, is the most recent period in Earth's history in which global warmth reached and remained at temperatures similar to those projected for the end of this century, about 2 degrees C to 3 degrees C warmer on average than today over the entire globe. This past warmer time interval preceded the ice ages but was recent enough, geologically, to be very similar to today in terms of ocean circulation and the position of the continents. Also, the populations of plants and animals were much like those of today, and so geologists can use their fossils to estimate past environmental conditions such as temperature and sea level.

Leaf Shape Responds to Temperature but Not CO2 in Acer rubrum

PubMed Central

Royer, Dana L.

2012-01-01

The degree of leaf dissection and the presence of leaf teeth, along with tooth size and abundance, inversely correlate with mean annual temperature (MAT) across many plant communities. These relationships form the core of several methods for reconstructing MAT from fossils, yet the direct selection of temperature on tooth morphology has not been demonstrated experimentally. It is also not known if atmospheric CO2 concentration affects leaf shape, limiting confidence in ancient climate reconstructions because CO2 has varied widely on geologic timescales. Here I report the results of growing Acer rubrum (red maple) in growth cabinets at contrasting temperature and CO2 conditions. The CO2 treatment imparted no significant differences in leaf size and shape, while plants grown at cooler temperatures tended to have more teeth and more highly dissected leaves. These results provide direct evidence for the selection of temperature on leaf shape in one species, and support a key link in many leaf-climate methods. More broadly, these results increase confidence for using leaf shape in fossils to reconstruct paleoclimate. PMID:23152921

Lessons learned from oxygen isotopes in modern precipitation applied to interpretation of speleothem records of paleoclimate from eastern Asia

NASA Astrophysics Data System (ADS)

Dayem, Katherine E.; Molnar, Peter; Battisti, David S.; Roe, Gerard H.

2010-06-01

Variability in oxygen isotope ratios collected from speleothems in Chinese caves is often interpreted as a proxy for variability of precipitation, summer precipitation, seasonality of precipitation, and/or the proportion of 18O to 16O of annual total rainfall that is related to a strengthening or weakening of the East Asian monsoon and, in some cases, to the Indian monsoon. We use modern reanalysis and station data to test whether precipitation and temperature variability over China can be related to changes in climate in these distant locales. We find that annual and rainy season precipitation totals in each of central China, south China, and east India have correlation length scales of ∼ 500 km, shorter than the distance between many speleothem records that share similar long-term time variations in δ18O values. Thus the short distances of correlation do not support, though by themselves cannot refute, the idea that apparently synchronous variations in δ18O values at widely spaced (> 500 km) caves in China are due to variations in annual precipitation amounts. We also evaluate connections between climate variables and δ18O values using available instrumental measurements of δ18O values in precipitation. These data, from stations in the Global Network of Isotopes in Precipitation (GNIP), show that monthly δ18O values generally do not correlate well with either local precipitation amount or local temperature, and the degree to which monthly δ18O values do correlate with them varies from station to station. For the few locations that do show significant correlations between δ18O values and precipitation amount, we estimate the differences in precipitation amount that would be required to account for peak-to-peak differences in δ18O values in the speleothems from Hulu and Dongge caves, assuming that δ18O scales with the monthly amount of precipitation or with seasonal differences in precipitation. Insofar as the present-day relationship between δ18O

Islamic Modernism and Architectural Modernism of Muhammadiyah’s Lio Mosque

NASA Astrophysics Data System (ADS)

Prajawisastra, A. F.; Aryanti, T.

2017-03-01

The Muhammadiyah’s Lio Mosque is one of the masterpieces of Achmad Noe’man, the great Indonesian mosque architect. The mosque was built as a community mosque at the center of Muhammadiyah’s quarter in Garut, West Java, in conjuction with the construction of the district’s Muhammadiyah branch. Having a shape out of the existing grip, the mosque has neither a dome nor a tajug tumpang tiga (three-tiered pyramidal roof) like other mosques nearby, but instead uses a gable roof and minarets towering. This article aims to analyze the architecture of the Lio Mosque and to learn Achmad Noe’man’s interpretation of modernism, both Islamic modernism and architectural modernism, reflected in the mosque design. Employing a qualitative approach, this study used observation and interviews with the mosque’s stakeholders. This article argues that the ideology of modernism, believed by Achmad Noe’man and the Muhammadiyah organization, was embodied in the Lio Mosque architecture.

Middle and Late Pleistocene glaciations in the southwestern Pamir and their effects on topography [Topography of the SW Pamir shaped by middle-late Pleistocene glaciation

DOE PAGES

Stübner, Konstanze; Grin, Elena; Hidy, Alan J.; ...

2017-03-27

Glacial chronologies provide insight into the evolution of paleo-landscapes, paleoclimate, topography, and the erosion processes that shape mountain ranges. In the Pamir of Central Asia, glacial morphologies and deposits indicate extensive past glaciations, whose timing and extent remain poorly constrained. Geomorphic data and 15 new 10Be exposure ages from moraine boulders and roches moutonnées in the southwestern Pamir document multiple Pleistocene glacial stages. The oldest exposure ages, View the MathML source113 ± 10ka, underestimate the age of the earliest preserved glacial advance and imply that the modern relief of the southwestern Pamir (peaks at ~5000–6000 m a.s.l.; valleys at ~2000–3000more » m a.s.l.) already existed in the late Middle Pleistocene. Younger exposure ages (~40–80 ka, ~30 ka) complement the existing Central Asian glacial chronology and reflect successively less extensive Late Pleistocene glaciations. The topography of the Pamir and the glacial chronologies suggest that, in the Middle Pleistocene, an ice cap or ice field occupied the eastern Pamir high-altitude plateau, whereas westward flowing valley glaciers incised the southwestern Pamir. Since the Late Pleistocene deglaciation, the rivers of the southwestern Pamir adjusted to the glacially shaped landscape. As a result, localized rapid fluvial incision and drainage network reorganization reflect the transient nature of the deglaciated landscape.« less

Middle and Late Pleistocene glaciations in the southwestern Pamir and their effects on topography [Topography of the SW Pamir shaped by middle-late Pleistocene glaciation

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

Stübner, Konstanze; Grin, Elena; Hidy, Alan J.

Glacial chronologies provide insight into the evolution of paleo-landscapes, paleoclimate, topography, and the erosion processes that shape mountain ranges. In the Pamir of Central Asia, glacial morphologies and deposits indicate extensive past glaciations, whose timing and extent remain poorly constrained. Geomorphic data and 15 new 10Be exposure ages from moraine boulders and roches moutonnées in the southwestern Pamir document multiple Pleistocene glacial stages. The oldest exposure ages, View the MathML source113 ± 10ka, underestimate the age of the earliest preserved glacial advance and imply that the modern relief of the southwestern Pamir (peaks at ~5000–6000 m a.s.l.; valleys at ~2000–3000more » m a.s.l.) already existed in the late Middle Pleistocene. Younger exposure ages (~40–80 ka, ~30 ka) complement the existing Central Asian glacial chronology and reflect successively less extensive Late Pleistocene glaciations. The topography of the Pamir and the glacial chronologies suggest that, in the Middle Pleistocene, an ice cap or ice field occupied the eastern Pamir high-altitude plateau, whereas westward flowing valley glaciers incised the southwestern Pamir. Since the Late Pleistocene deglaciation, the rivers of the southwestern Pamir adjusted to the glacially shaped landscape. As a result, localized rapid fluvial incision and drainage network reorganization reflect the transient nature of the deglaciated landscape.« less

The Martian paleoclimate and enhanced atmospheric carbon dioxide

NASA Technical Reports Server (NTRS)

Cess, R. D.; Owen, T.; Ramanathan, V.

1980-01-01

Current evidence indicates that the Martian surface is abundant with water presently in the form of ice, while the atmosphere was at one time more massive with a past surface pressure of as much as 1 atm of CO2. In an attempt to understand the Martian paleoclimate, a past CO2-H2O greenhouse was modeled and global temperatures which are consistent with an earlier presence of liquid surface water are found in agreement with the extensive evidence for past fluvial erosion. An important aspect of the CO2-H2O greenhouse model is the detailed inclusion of CO2 hot bands. For a surface pressure of 1 atm of CO2, the present greenhouse model predicts a global mean surface temperature of 294 K, but if the hot bands are excluded, a surface temperature of only 250 K is achieved.

AMS applications to the paleoclimate changing study in China

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

Li, K.; Chen, T.M.; Yuan, D.X.

1995-12-01

To study the paleoclimates changing in China, a high-resolution AMS radio-carbon dating of a loess profile at Weinan, Shaanxi Province, has been carried out and an age of 10,300 BP has been assigned to be the beginning of the HOLOCENE in the studied areas. In the south of China, a stalagmite of 1.2-m high taken from Panlong-dong cave, Guilin, Guangxi Province, has also been studied. The dating with micro-stratification sampling shows that the climate in HOLOCENE was generally damp and warm, but there was a short cola period during 10-11 Ka BP. The resolution of AMS carbon dating of stalagmitemore » is 100 years for the warm and damp period and 500 years for the dry and cold period.« less

Phenotypic Plasticity of Leaf Shape along a Temperature Gradient in Acer rubrum

PubMed Central

Royer, Dana L.; Meyerson, Laura A.; Robertson, Kevin M.; Adams, Jonathan M.

2009-01-01

Both phenotypic plasticity and genetic determination can be important for understanding how plants respond to environmental change. However, little is known about the plastic response of leaf teeth and leaf dissection to temperature. This gap is critical because these leaf traits are commonly used to reconstruct paleoclimate from fossils, and such studies tacitly assume that traits measured from fossils reflect the environment at the time of their deposition, even during periods of rapid climate change. We measured leaf size and shape in Acer rubrum derived from four seed sources with a broad temperature range and grown for two years in two gardens with contrasting climates (Rhode Island and Florida). Leaves in the Rhode Island garden have more teeth and are more highly dissected than leaves in Florida from the same seed source. Plasticity in these variables accounts for at least 6–19 % of the total variance, while genetic differences among ecotypes probably account for at most 69–87 %. This study highlights the role of phenotypic plasticity in leaf-climate relationships. We suggest that variables related to tooth count and leaf dissection in A. rubrum can respond quickly to climate change, which increases confidence in paleoclimate methods that use these variables. PMID:19893620

Using modern analogues to reconstruct past landcover

NASA Astrophysics Data System (ADS)

Brewer, Simon

2016-04-01

The physical cover of the earth plays an important role in the earth system. It affects the climate through feedbacks such as albedo and surface roughness, forms part of the carbon cycle as both sink and source and is both affected by and can affect human societies. Reconstructing past changes in land use and land cover helps to understand how these interactions may have changed over time, and provides important boundary conditions for paleoclimate models. Pollen assemblages, extracted from sedimentary sequences, provide one of the most abundant sources of information about past changes in land cover over the Holocene period. However, the relationship between plant cover and sedimentary pollen abundance is complex and non-linear, being affected by differential dispersal, production and taxonomic resolution. One method to correct for this and provide quantified estimates of past land cover is to calibrate modern pollen assemblages against contemporary remotely sensed estimates of land cover. Results will be presented from developing such a calibration for a set of European modern pollen samples and AVHRR-based tree cover estimates. An emphasis will be placed on the output of validation tests of the calibration, and what this indicates for the predictive skill of this approach. The calibration will then be applied to a set of pollen sequences for the European continent for the past 11,000 years, and the patterns of reconstructed land cover will be discussed.

How four different political systems have shaped the modernization of traditional Korean medicine between 1900 and 1960.

PubMed

Dongwon, Shin

2008-03-01

In this paper, I examine the modern formation of traditional Korean medicine and discuss the characteristics of the modernization, or modernity, of the medicine. I probe for answers to three questions: first, prior to the twentieth century, what were the main factors that traditional Korean medicine needed to be transformed into a new one? Second, how did four states, the Taehan Empire, colonial Korea, North Korea, and South Korea, treat traditional medicine differently, and why? Third, what are the main characteristics of the modernization of traditional Korean medicine? In examining these questions, I found the following four factors to be important in shaping the modern formation of traditional Korean medicine during the twentieth century: first, the influences of Western science and institutions; second, the rise of nationalism; third, the economics of the state; and fourth, the effectiveness of traditional medicine. Among them, the introduction of Western science and institutions was the most important factor. All the different states in modern Korea realized that Western science and institutions were indispensable for the country to be a powerful nation and to enhance people's welfare. The degree of confidentiality in scientific Western medicine determined the number of traditional medical practitioners and their professional status. The modernization also was greatly affected by modern nationalism, which clashed with Westernization. Many Koreans and the Korean governments regarded the traditional medicine as something culturally valuable to protect from Western culture. Especially, the majority of Koreans who had experienced the cruelty of the Japanese rule under colonization tended to believe that Japan, a foreign ruler, had suppressed traditional Korean medicine as a liquidation policy of Korean culture during the colonial period. This belief contributed greatly to the recovery of the traditional doctors' prestige in South Korea and North Korea after

Towards a new paleotemperature proxy from reef coral occurrences.

PubMed

Lauchstedt, Andreas; Pandolfi, John M; Kiessling, Wolfgang

2017-09-05

Global mean temperature is thought to have exceeded that of today during the last interglacial episode (LIG, ~ 125,000 yrs b.p.) but robust paleoclimate data are still rare in low latitudes. Occurrence data of tropical reef corals may provide new proxies of low latitude sea-surface temperatures. Using modern reef coral distributions we developed a geographically explicit model of sea surface temperatures. Applying this model to coral occurrence data of the LIG provides a latitudinal U-shaped pattern of temperature anomalies with cooler than modern temperatures around the equator and warmer subtropical climes. Our results agree with previously published estimates of LIG temperatures and suggest a poleward broadening of the habitable zone for reef corals during the LIG.

Surface Mass Balance of the Greenland Ice Sheet Derived from Paleoclimate Reanalysis

NASA Astrophysics Data System (ADS)

Badgeley, J.; Steig, E. J.; Hakim, G. J.; Anderson, J.; Tardif, R.

2017-12-01

Modeling past ice-sheet behavior requires independent knowledge of past surface mass balance. Though models provide useful insight into ice-sheet response to climate forcing, if past climate is unknown, then ascertaining the rate and extent of past ice-sheet change is limited to geological and geophysical constraints. We use a novel data-assimilation framework developed under the Last Millennium Reanalysis Project (Hakim et al., 2016) to reconstruct past climate over ice sheets with the intent of creating an independent surface mass balance record for paleo ice-sheet modeling. Paleoclimate data assimilation combines the physics of climate models and the time series evidence of proxy records in an offline, ensemble-based approach. This framework allows for the assimilation of numerous proxy records and archive types while maintaining spatial consistency with known climate dynamics and physics captured by the models. In our reconstruction, we use the Community Climate System Model version 4, CMIP5 last millennium simulation (Taylor et al., 2012; Landrum et al., 2013) and a nearly complete database of ice core oxygen isotope records to reconstruct Holocene surface temperature and precipitation over the Greenland Ice Sheet on a decadal timescale. By applying a seasonality to this reconstruction (from the TraCE-21ka simulation; Liu et al., 2009), our reanalysis can be used in seasonally-based surface mass balance models. Here we discuss the methods behind our reanalysis and the performance of our reconstruction through prediction of unassimilated proxy records and comparison to paleoclimate reconstructions and reanalysis products.

Jurassic-Cretaceous paleogeography, paleoclimate and upwelling of the northern margin of Tethys

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

Golonka, J.; Krobicki, M.

The Jurassic and Cretaceous global paleogeographic reconstructions illustrate the changing configuration of mountains, land, shallow seas and deep ocean basins. Active plate boundaries, such as spreading centers and subduction zones, are also shown. The Pliensbachian, Toarcian, Bathonian, Oxfordian-Kimmeridgian, Tithonian-Berriasian, Valanginian, Albian, Turonian and Maastrichtian maps were generated The outlines of paleogeography are used as input for paleoclimatic modeling. The PALEOCLIMATE program models global atmospheric pressure, derive paleo-wind directions and estimate the likelihood of coastal upwelling. The program is based on the paleoclimatic methods first developed by Judith Parrish, adopted by C. R. Scotese and modified by M. I. Ross. Themore » maps depict air pressure, wind directions, humid zones and areas favorable for upwelling conditions plotted on the paleogeographic background. Paleoclimate modeling suggests that prevailing Jurassic-Cretaceous wind directions in the northern Tethys area were from north-northeast. These winds were parallel to the axis of Czorsztyn ridge. The ridge was uplifted between Magura and Pieniny basins as the result of extension during Jurassic supercontinent breakup. The upwelling may have been induced at the southeastern margin of the ridge. The model is consistent with rock records, especially from the upper part of ammonitico rosso type Czorsztyn formation. Mass occurrence of Tithonian and Berriasian brachiopods was probably controlled by upwelling-induced trophic relationships which is resulted in the intense growth of benthic organisms on the ridge. This is additionally supported by the presence of phosphorites at localities which corresponded to the continental shelf/slope transition.« less

Studies of Cave Sediments: Physical and Chemical Records of Paleoclimate (Revised Edition)

NASA Astrophysics Data System (ADS)

Baker, Andy

2007-10-01

Caves have long fascinated humankind, from prehistory to present-day tourism. Caves are also a subject for a range of scientific investigations, including cave biology, archaeology, paleoclimatology, geology, hydrology, and geomorphology. One of the benefits caves provide is their role as a repository of material that might not otherwise survive on the Earth's surface, due to caves' interiors being protected from physical erosion by nature of their underground locations. Studies of Cave Sediments focuses on this role as a repository, in particular on Quaternary (historic to 1.8 million years old) paleoclimate information preserved in cave sediments.

Using paleoclimate data to improve models of the Antarctic Ice Sheet

NASA Astrophysics Data System (ADS)

King, M. A.; Phipps, S. J.; Roberts, J. L.; White, D.

2016-12-01

Ice sheet models are the most descriptive tools available to simulate the future evolution of the Antarctic Ice Sheet (AIS), including its contribution towards changes in global sea level. However, our knowledge of the dynamics of the coupled ice-ocean-lithosphere system is inevitably limited, in part due to a lack of observations. Furthemore, to build computationally efficient models that can be run for multiple millennia, it is necessary to use simplified descriptions of ice dynamics. Ice sheet modeling is therefore an inherently uncertain exercise. The past evolution of the AIS provides an opportunity to constrain the description of physical processes within ice sheet models and, therefore, to constrain our understanding of the role of the AIS in driving changes in global sea level. We use the Parallel Ice Sheet Model (PISM) to demonstrate how paleoclimate data can improve our ability to predict the future evolution of the AIS. A large, perturbed-physics ensemble is generated, spanning uncertainty in the parameterizations of four key physical processes within ice sheet models: ice rheology, ice shelf calving, and the stress balances within ice sheets and ice shelves. A Latin hypercube approach is used to optimally sample the range of uncertainty in parameter values. This perturbed-physics ensemble is used to simulate the evolution of the AIS from the Last Glacial Maximum ( 21,000 years ago) to present. Paleoclimate records are then used to determine which ensemble members are the most realistic. This allows us to use data on past climates to directly constrain our understanding of the past contribution of the AIS towards changes in global sea level. Critically, it also allows us to determine which ensemble members are likely to generate the most realistic projections of the future evolution of the AIS.

A simple conceptual model to interpret the 100 000 years dynamics of paleo-climate records

NASA Astrophysics Data System (ADS)

Quiroga Lombard, C. S.; Balenzuela, P.; Braun, H.; Chialvo, D. R.

2010-10-01

Spectral analyses performed on records of cosmogenic nuclides reveal a group of dominant spectral components during the Holocene period. Only a few of them are related to known solar cycles, i.e., the De Vries/Suess, Gleissberg and Hallstatt cycles. The origin of the others remains uncertain. On the other hand, time series of North Atlantic atmospheric/sea surface temperatures during the last ice age display the existence of repeated large-scale warming events, called Dansgaard-Oeschger (DO) events, spaced around multiples of 1470 years. The De Vries/Suess and Gleissberg cycles with periods close to 1470/7 (~210) and 1470/17 (~86.5) years have been proposed to explain these observations. In this work we found that a conceptual bistable model forced with the De Vries/Suess and Gleissberg cycles plus noise displays a group of dominant frequencies similar to those obtained in the Fourier spectra from paleo-climate during the Holocene. Moreover, we show that simply changing the noise amplitude in the model we obtain similar power spectra to those corresponding to GISP2 δ18O (Greenland Ice Sheet Project 2) during the last ice age. These results give a general dynamical framework which allows us to interpret the main characteristic of paleoclimate records from the last 100 000 years.

The investigation of terrestrial analogs for the paleoclimate of Mars

NASA Astrophysics Data System (ADS)

Thorpe, M.; Hurowitz, J.; Dehouck, E.

2016-12-01

The paleoclimate of Mars is recorded in sedimentary rocks and deposits, with geochemical and mineralogical lines of evidence illustrating an active hydrologic cycle and aqueous weathering environment. The nature of this paleoclimate remains a debatable subject, with several competing hypothesis existing from warm and wet to cold and icy. However, sedimentary processes in basaltic terrains are understudied, leading to an inadequate reference frame for the sedimentary record of Mars. Therefore, investigating the effects of climate on basaltic terrestrial analogs will help in establishing a context for understanding the ancient conditions of Mars. The Columbia River Basalts in Idaho, USA will serve as conditions in a warm and wet climate, while the weathering of Icelandic Basalts in southwestern Iceland will provide a cold and wet climate scenario. In the warm and wet conditions of Idaho, Miocene basaltic source rock is broken down by physical and chemical weathering, transported by streams and deposited locally as small deltas. The sediment that accumulates preserves the basaltic provenance mineralogy in grain sizes as small as silt. The major elemental geochemistry displays chemical weathering trends that are consistent with decreasing grain size, and interpreted as mafic mineral dissolution (i.e., olivine and pyroxenes). Clay mineral phases are separated into the finest grain size fraction during the sedimentation process and are identified as smectite clays. A similar story of preserving basaltic mineralogy is illustrated by Icelandic deposits, except mechanical breakdown of the sediment appears to have a larger impact. Primary mafic minerals are identified in even the clay size fraction of the Icelandic fluvial delta deposits. Additionally, there are limited abundances of clay mineral phases, with more obvious contributions of poorly crystalline phases in the less than 2 micron fraction. The preservation of basaltic provenance in the mineralogy of sediments

The use of Sphagnum cellulose oxygen isotope ratios in ombrotrophic peatlands as a proxy for paleoclimate.

NASA Astrophysics Data System (ADS)

Taylor, M.; Pendall, E.; Jackson, S.; Booth, R. K.; Nichols, J. E.; Huang, Y.

2006-12-01

Developing proxies for discerning paleoclimate that are independent of the pollen record can provide insight into various aspects of climate variability and improve confidence in the interpretation of climate-vegetation interactions. To date, proxies including plant macrofossils, humification indices, testate amoebae, and ratios of n-alkane abundances have been used to infer past climate variability from temperate ombrotrophic peatlands in upper Midwestern North America. These proxies are used to infer past changes in surface-moisture conditions, which in ombrotrophic peatlands is primarily a function of precipitation and temperature. This study investigates the potential uses of stable oxygen isotopes to complement hydrologic proxies. δ18O of surface water and Sphagnum moss cellulose from bogs throughout North America indicates a correlation between average growing season temperatures and δ18O-values. The existence of a modern temperature signal in moss cellulose suggests that δ18O-derived records will not only complement paleohydrological records, but also help assess relative changes in precipitation and temperature. Humification and testate amoebae data from two cores taken from Minden and Irwin Smith Bogs in central and northeastern Michigan have recorded several extreme drought events during the Holocene, including one at 1000 YBP. Comparison of δ18O-values of picked Sphagnum remains to down-core humification and testate amoebae data suggest good temporal correspondence, with the δ18O-values around 1000 YBP indicating a warmer growing season.

Treating pre-instrumental data as "missing" data: using a tree-ring-based paleoclimate record and imputations to reconstruct streamflow in the Missouri River Basin

NASA Astrophysics Data System (ADS)

Ho, M. W.; Lall, U.; Cook, E. R.

2015-12-01

Advances in paleoclimatology in the past few decades have provided opportunities to expand the temporal perspective of the hydrological and climatological variability across the world. The North American region is particularly fortunate in this respect where a relatively dense network of high resolution paleoclimate proxy records have been assembled. One such network is the annually-resolved Living Blended Drought Atlas (LBDA): a paleoclimate reconstruction of the Palmer Drought Severity Index (PDSI) that covers North America on a 0.5° × 0.5° grid based on tree-ring chronologies. However, the use of the LBDA to assess North American streamflow variability requires a model by which streamflow may be reconstructed. Paleoclimate reconstructions have typically used models that first seek to quantify the relationship between the paleoclimate variable and the environmental variable of interest before extrapolating the relationship back in time. In contrast, the pre-instrumental streamflow is here considered as "missing" data. A method of imputing the "missing" streamflow data, prior to the instrumental record, is applied through multiple imputation using chained equations for streamflow in the Missouri River Basin. In this method, the distribution of the instrumental streamflow and LBDA is used to estimate sets of plausible values for the "missing" streamflow data resulting in a ~600 year-long streamflow reconstruction. Past research into external climate forcings, oceanic-atmospheric variability and its teleconnections, and assessments of rare multi-centennial instrumental records demonstrate that large temporal oscillations in hydrological conditions are unlikely to be captured in most instrumental records. The reconstruction of multi-centennial records of streamflow will enable comprehensive assessments of current and future water resource infrastructure and operations under the existing scope of natural climate variability.

Late Quaternary eolian and alluvial response to paleoclimate, Canyonlands, southeastern Utah

USGS Publications Warehouse

Reheis, M.C.; Reynolds, R.L.; Goldstein, H.; Roberts, H.M.; Yount, J.C.; Axford, Y.; Cummings, L.S.; Shearin, N.

2005-01-01

In upland areas of Canyonlands National Park, Utah, thin deposits and paleosols show late Quaternary episodes of eolian sedimentation, pedogenesis, and climate change. Interpretation of the stratigraphy and optically stimulated luminescence ages of eolian and nearby alluvial deposits, their pollen, and intercalated paleosols yields the following history: (1) Eolian deposition at ca. 46 ka, followed by several episodes of alluviation from some time before ca. 40 ka until after 16 ka (calibrated). (2) Eolian deposition from ca. 17 ka to 12 ka, interrupted by periods of pedogenesis, coinciding with late Pleistocene alluviation as local climate became warmer and wetter. (3) A wetter period from 12 to 8.5 ka corresponding to the peak of summer monsoon influence, during which soils formed relatively quickly by infiltration of eolian silt and clay, and trees and grasses were more abundant. (4) A drier period between ca. 8.5 and 6 ka during which sheetwash deposits accumulated and more desertlike vegetation was dominant; some dunes were reactivated at ca. 8 ka. (5) Episodic eolian and fluvial deposition during a wetter, cooler period that began at ca. 6 ka and ended by ca. 3-2 ka, followed by a shift to drier modern conditions; localized mobilization of dune sand has persisted to the present. These interpretations are similar to those of studies at the Chaco dune field, New Mexico, and the Tusayan dune field, Arizona, and are consistent with paleoclimate interpretations of pollen and packrat middens in the region. A period of rapid deposition and infiltration of eolian dust derived from distant igneous source terranes occurred between ca. 12 and 8 ka. Before ca. 17 ka, and apparently back to at least 45 ka, paleosols contain little or no such infiltrated dust. After ca. 8 ka, either the supply of dust was reduced or the more arid climate inhibited translocation of dust into the soils. ?? 2005 Geological Society of America.

Reconstructing the leading mode of multi-decadal North Atlantic variability over the last two millenia using functional paleoclimate networks

NASA Astrophysics Data System (ADS)

Franke, Jasper G.; Werner, Johannes; Donner, Reik V.

2017-04-01

The increasing availability of high-resolution North Atlantic paleoclimate proxies allows to not only study local climate variations in time, but also temporal changes in spatial variability patterns across the entire region possibly controlled by large-scale coherent variability modes such as the North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation. In this study, we use functional paleoclimate network analysis [1,2] to investigate changes in the statistical similarity patterns among an ensemble of high-resolution terrestrial paleoclimate records from Northern Europe included in the Arctic 2k data base. Specifically, we construct complex networks capturing the mutual statistical similarity of inter-annual temperature variability recorded in tree ring records, ice cores and lake sediments for multidecadal time windows covering the last two millenia. The observed patterns of co-variability are ultimately connected to the North Atlantic atmospheric circulation and most prominently to multidecadal variations of the NAO. Based on the inferred networks, we study the dynamical similarity between regional clusters of archives defined according to present-day inter-annual temperature variations across the study region. This analysis identifies those time-dependent inter-regional linkages that are most informative about the leading-order North Atlantic climate variability according to a recent NAO reconstruction for the last millenium [3]. Based on these linkages, we extend the existing reconstruction to obtain qualitative information on multidecadal to centennial scale North Atlantic climate variability over the last two millenia. In general, we find a tendency towards a dominating positive NAO phase interrupted by pronounced and extended intervals of negative NAO. Relatively rapid transitions between both types of behaviour are present during distinct periods including the Little Ice Age, the Medieval Climate Anomaly and for the Dark Ages Little Ice Age

Oxygen Isotope Calibration Study of Modern Diatoms in Freshwater Environments: Implications for Biogenic Silica as a Paleoclimate Proxy

NASA Astrophysics Data System (ADS)

Dodd, J. P.; Sharp, Z. D.; Fawcett, P.

2008-12-01

Oxygen isotope values of biogenic silica from diatom frustules are a commonly used proxy in freshwater and marine environments, and provide a valuable archive of paleoclimatic information such as temperature and water cycle processes. Advances in analytical techniques have made oxygen isotope measurements of diatom silica more robust; however, to date, there are multiple published fractionation factors for biogenic silica, with no general consensus on which is 'correct.' Previous studies (e.g. Moschen et al, 2005) demonstrated that there is no difference in SiO2-H2O fractionation between different size fractions of diatoms and, therefore, no species-dependent effects. The SiO2-H2O fractionation factors observed in laboratory grown diatoms analyzed by Brandriss et al. (1998) and modern lacustrine diatoms (Moschen et al., 2005) are in close agreement (τ = -0.2‰/°C) and are defined by the equations 1000lnα SiO2-H2O = 15.56 (103 T-1) - 20.92 and 1000lnα SiO2-H2O = 20.5 (103 T-1) - 36.2, respectively. However, these studies are not in agreement with other published SiO2-H2O fractionation factors for biogenic silica in marine and freshwater environments. In order to effectively utilize diatom δ18O values as a climate proxy, it is necessary to understand how oxygen isotopes are fractionated during silica frustule formation and identify potential errors in δ18O values obtained through different analytic/purification processes. Here we present oxygen isotope data from modern diatom species collected from a wide variety of natural riverine and lacustrine environments in northern New Mexico, USA. Temperatures at collection sites ranged from 5.5°C to 37.8°C. Preliminary isotope data indicate a SiO2-H2O fractionation factor identical to Brandriss et al. (1998). Additional experiments were undertaken to examine the effect of differing chemical purification techniques (i.e. HNO3, H2O2, and NaOH) on modern diatoms to see if processing techniques might affect the δ18O

A national perspective on paleoclimate streamflow and water storage infrastructure in the conterminous United States

NASA Astrophysics Data System (ADS)

Ho, Michelle; Lall, Upmanu; Sun, Xun; Cook, Edward

2017-04-01

Large-scale water storage infrastructure in the Conterminous United States (CONUS) provides a means of regulating the temporal variability in water supply with storage capacities ranging from seasonal storage in the wetter east to multi-annual and decadal-scale storage in the drier west. Regional differences in water availability across the CONUS provides opportunities for optimizing water dependent economic activities, such as food and energy production, through storage and transportation. However, the ability to sufficiently regulate water supplies into the future is compromised by inadequate monitoring of non-federally-owned dams that make up around 97% of all dams. Furthermore, many of these dams are reaching or have exceeded their economic design life. Understanding the role of dams in the current and future landscape of water requirements in the CONUS is needed to prioritize dam safety remediation or identify where redundant dams may be removed. A national water assessment and planning process is needed for addressing water requirements, accounting for regional differences in water supply and demand, and the role of dams in such a landscape. Most dams in the CONUS were designed without knowledge of devastating floods and prolonged droughts detected in multi-centennial paleoclimate records, consideration of projected climate change, nor consideration of optimal operation across large-scale regions. As a step towards informing water supply across the CONUS we present a paleoclimate reconstruction of annual streamflow across the CONUS over the past 555 years using a spatially and temporally complete paleoclimate record of summer drought across the CONUS targeting a set of US Geological Survey streamflow sites. The spatial and temporal structures of national streamflow variability are analyzed using hierarchical clustering, principal component analysis, and wavelet analyses. The reconstructions show signals of contemporary droughts such as the Dust Bowl (1930s

Phosphate mineral formation in Lake Baikal sediments and implications for paleoclimate

NASA Astrophysics Data System (ADS)

Fagel, N.; Alleman, L. Y.; André, L.; Cloots, R.; Hatert, F.; Juvigné, E.; Renson, V.

2003-04-01

The more than 20 million years old Lake Baikal sedimentary record provides a good climate archive. While most paleoclimate reconstructions are mainly based on biotic proxies, we tested in this study other minerogenic tracers. In particular, it was suggested that the formation of authigenic and/or diagenetic phosphate minerals in Baïkal sediments underlines transitions from glacial to interglacial periods (Deike et al., 1997). The phosphate mineral formation previously evidenced (Müller et al., 2002) may be sensitive to suspended sediment concentrations: glacial periods are characterised by high detrital discharge, interglacial intervals are marked by low detrital supply but high biogenic sedimentation. Phosphate minerals were observed in Baïkal sediments from recent to 65 kyr BP. Their abundance was related to the sedimentation rate, the phosphate enrichment layers being particularly common on low sedimentation site, i.e., the Academician Ridge. Major and trace elements have been analysed by ICP-AES and ICP-MS on four cores drilled on topographic hills, in the southern basin (Posolsky bank, CON01-604), in the central part (Academician Ridge, VER98-1-3 and VER98-1-14) and in the northern basin (Continent Ridge, CON01-603). The geochemical signature is consistent with the occurrence of Mn-Fe-phosphate minerals. For instance P2O5 reaches up to 3% wt. relative to a mean value of 0.3 in the background sediment, MnO2 presents an enrichment factor up to 6. There is no associated enrichment in any of the trace elements measured at the same levels. In the sediments, those P-Mn-Fe rich levels are related either to sparse millimetric dark concretions or to a layer (or a group of layers) defined by an alignment of numerous concretions but there is no so-called crusts. The concretions, isolated by >63 mm sieving, present a lamellar morphology. They are identified as Fe-phosphate phases with a variable proportion of Mn. The powder diffraction diagram is consistent with

The Origin and Evolutionary Consequences of Skeletal Traits Shaped by Embryonic Muscular Activity, from Basal Theropods to Modern Birds.

PubMed

Vargas, Alexander O; Ruiz-Flores, Macarena; Soto-Acuña, Sergio; Haidr, Nadia; Acosta-Hospitaleche, Carolina; Ossa-Fuentes, Luis; Muñoz-Walther, Vicente

2017-12-01

Embryonic muscular activity (EMA) is involved in the development of several distinctive traits of birds. Modern avian diversity and the fossil record of the dinosaur-bird transition allow special insight into their evolution. Traits shaped by EMA result from mechanical forces acting at post-morphogenetic stages, such that genes often play a very indirect role. Their origin seldom suggests direct selection for the trait, but a side-effect of other changes such as musculo-skeletal rearrangements, heterochrony in skeletal maturation, or increased incubation temperature (which increases EMA). EMA-shaped traits like sesamoids may be inconstant, highly conserved, or even disappear and then reappear in evolution. Some sesamoids may become increasingly influenced in evolution by genetic-molecular mechanisms (genetic assimilation). There is also ample evidence of evolutionary transitions from sesamoids to bony eminences at tendon insertion sites, and vice-versa. This can be explained by newfound similarities in the earliest development of both kinds of structures, which suggest these transitions are likely triggered by EMA. Other traits that require EMA for their formation will not necessarily undergo genetic assimilation, but still be conserved over tens and hundreds of millions of years, allowing evolutionary reduction and loss of other skeletal elements. Upon their origin, EMA-shaped traits may not be directly genetic, nor immediately adaptive. Nevertheless, EMA can play a key role in evolutionary innovation, and have consequences for the subsequent direction of evolutionary change. Its role may be more important and ubiquitous than currently suspected. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Methodological Features of Educational System Modernization in the Context of the "Economy of Knowledge"

ERIC Educational Resources Information Center

Karpova, Natalia Konstantinovna; Uvarovsky, Alexander Pavlovich; Mareev, Vladimir Ivanovich; Petrova, Nina Petrovna; Borzilov, Yuri Petrovich

2016-01-01

The article is devoted to some methodological features of modernization in modern education in the context of "the knowledge economy" development which is aimed at shaping new mental potential of the modern state. Features and prerequisites for the emergence of the knowledge economy, the priorities of which include the development and…

Evidence for a possible modern and mid-Holocene solar influence on climate from Lake Titicaca, South America

NASA Astrophysics Data System (ADS)

Theissen, K. M.; Dunbar, R. B.

2005-12-01

In tropical regions, there are few paleoclimate archives with the necessary resolution to investigate climate variability at interannual-to-decadal timescales prior to the onset of the instrumental record. Interannual variability associated with the El Niño Southern Oscillation (ENSO) is well documented in the instrumental record and the importance of the precessional forcing of millennial variability has been established in studies of tropical paleoclimate records. In contrast, decade-to-century variability is still poorly understood. Here, we examine interannual to decadal variability in the northern Altiplano of South America using digital image analysis of a floating interval of varved sediments of middle Holocene age (~6160-6310 yr BP) from Lake Titicaca. Multi-taper method (MTM) and wavelet frequency-domain analyses were performed on a time series generated from a gray-scaled digital image of the mm-thick laminations. Our results indicate significant power at a decadal periodicity (10-12 years) associated with the Schwabe cycle of solar activity. Frequency-domain analysis also indicates power at 2-2.5 year periodicities associated with ENSO. Similarly, spectral analysis of a 75 year instrumental record of Titicaca lake level shows significant power at both solar and ENSO periodicities. Although both of the examined records are short, our results imply that during both the mid-Holocene and modern times, solar and ENSO variability may have contributed to high frequency climate fluctuations over the northern Altiplano. We suspect that solar influence on large-scale atmospheric circulation features may account for the decadal variability in the mid-Holocene and present-day water balance of the Altiplano.

Rapid regional surface uplift of the northern Altiplano plateau revealed by multiproxy paleoclimate reconstruction

NASA Astrophysics Data System (ADS)

Kar, Nandini; Garzione, Carmala N.; Jaramillo, Carlos; Shanahan, Timothy; Carlotto, Victor; Pullen, Alex; Moreno, Federico; Anderson, Veronica; Moreno, Enrique; Eiler, John

2016-08-01

The central Altiplano is inferred to have experienced ∼ 2.5 ± 1km surface uplift between ∼10 and 6 Ma, while the southern Altiplano experienced a similar magnitude of surface uplift that began earlier, between ∼16 and 9 Ma. To properly constrain the along strike timing of the Altiplano plateau surface uplift, it is necessary to know how and when the northernmost part of the Altiplano plateau evolved. We reconstruct the paleoclimate and infer the corresponding paleoelevation from the Miocene-Pliocene deposits of the Descanso-Yauri basin (14-15°S) in the northernmost part of the Altiplano plateau using 4 different proxies, including carbonate clumped isotope composition (i.e., Δ47 values), carbonate δ18Oc, leaf wax δDwax and pollen assemblages from paleosol, lacustrine and palustrine carbonates and organic-rich sediments. The isotopic signatures reflect past climate conditions of mean annual air temperature (Δ47) and meteoric water isotope values (δ18Oc, δDwax). Our results show that the northernmost plateau remained at low elevation (0.9 ± 0.8 to 2.1 ± 0.9km) until late Miocene time (∼9 Ma) characterized by ∼15 °C warmer than modern temperature (mean annual air temperature of 23 ± 4 °C, 2σ), low elevation vegetation and precipitation signature with reconstructed □ δ18Omw (VSMOW) of - 8.3 ± 2.0 ‰ (2 σ) from carbonate (δ18Oc) and - 8.6 ± 1.8 ‰ (2 σ) from leaf wax (δDwax). Modern elevations of 4 km were not reached until 5.4 ± 1.0Ma, as indicated by a negative shift in δDwax (VSMOW) from - 143.4 ± 12.8 ‰ (2 σ) to - 209.2 ± 21.1 ‰ (2 σ) between 9.1 ± 0.7 and 5.4 ± 1.0Ma. The timing of surface uplift of the northernmost Altiplano is consistent with the evidence for late Miocene surface uplift of the central Altiplano (16-19°S) between 10 and 6 Ma, and indicates that regional scale uplift in the northern-central plateau significantly postdates the onset of surface uplift in the southern Altiplano (19-22°S) between ∼16

Paleoclimate and Amerindians: Evidence from stable isotopes and atmospheric circulation

USGS Publications Warehouse

Lovvorn, M.B.; Frison, G.C.; Tieszen, L.L.

2001-01-01

Two Amerindian demographic shifts are attributed to climate change in the northwest plains of North America: at ???11,000 calendar years before present (yr BP), Amerindian culture apparently split into foothills-mountains vs. plains biomes; and from 8,000-5,000 yr BP, scarce archaeological sites on the open plains suggest emigration during xeric "Altithermal" conditions. We reconstructed paleoclimates from stable isotopes in prehistoric bison bone and relations between weather and fractions of C4 plants in forage. Further, we developed a climate-change model that synthesized stable isotope, existing qualitative evidence (e.g., palynological, erosional), and global climate mechanisms affecting this midlatitude region. Our isotope data indicate significant warming from ???12,400 to 11,900 yr BP, supporting climate-driven cultural separation. However, isotope evidence of apparently wet, warm conditions at 7,300 yr BP refutes emigration to avoid xeric conditions. Scarcity of archaeological sites is best explained by rapid climate fluctuations after catastrophic draining of the Laurentide Lakes, which disrupted North Atlantic Deep Water production and subsequently altered monsoonal inputs to the open plains.

Testing the Sun-climate Connection with Paleoclimate Data

NASA Technical Reports Server (NTRS)

Crowley, Thomas J.; Howard, Matthew K.

1990-01-01

If there is a significant sun-climate connection, it should be detectable in high-resolution paleoclimate records. Of particular interest is the last few thousand years, where we have both indices of solar variability (C-14 and Be-10) and climate variations (alpine glaciers, tree rings, ice cores, corals, etc.). Although there are a few exceptions, statistical analyses of solar and climate records generally indicates a flickering relationship between the two -- sometimes it seems to be present, sometimes not. The most repeatable solar climate periods occur at approx. 120 and approx. 56 yrs, although there is also evidence for approx. 420 and approx. 200 yrs. power in some records. However, coherence between solar and climate spectra is usually low, and occurrence of solar spectra in climate records is sometimes dependent on choice of analysis program. These results suggest in general a relatively weak sun-climate link on time scales of decades to centuries. This conclusion is consistent with previous studies and with the observation that inferred climate fluctuations of 1.0 to 1.5 C on this time scale would require solar constant variations of approximately 0.5 to 1.0 percent. This change in forcing is almost an order of magnitude greater than observed changes over the last solar cycle and appears to be on the far-outer limit of acceptable changes for a Maunder Minimum-type event.

Annual growth bands in Hymenaea courbaril: implications for utilization in tropical paleoclimate reconstructions.

NASA Astrophysics Data System (ADS)

Westbrook, J. A.; Guilderson, T.; Colinvaux, P. A.; D'Arrigo, R.

2004-12-01

Instrumental records of environmental variables such as temperature and precipitation are necessary to understand climate patterns and variability. In general, such observations from the tropics do not exist prior to the late 19th century, and existing records contain large spatial and temporal gaps and are sparsely distributed. An important source of annual temperature and precipitation proxy-data comes from the regular annual growth rings of wood formed by trees. Tree growth rings occur in response to periodic seasonal changes in the environment. Although expansive and diverse in number and ecology, a vast majority of tropical trees do not produce distinct annual growth rings. Because of this, tropical dendrochronology and paleoclimate reconstructions have lagged behind their temperate and higher latitude cousins. Distinct secondary growth rings were investigated in a single individual of the tropical hardwood legume Hymenaea courbaril felled within the City of David, Republic of Panama. Rings that maintained circuitry were considered annual and were sampled for 14C. Radiocarbon values from the secondary growth rings from this specimen were compared with annual reference radiocarbon values from wood and air in North America, New Zealand and Germany. This comparison demonstrated that the secondary growth rings formed by H. courbaril were determined to be annual in nature in this one stem disk specimen. To confirm the consistency of the annual nature of the secondary growth rings in H. courbaril, nine (9) additional specimens were recovered from the small hamlet of San Carlos y Algarobbo in western Panama between the town of David and the cordillera approximately ~30km from the site of the first tree sample. Of the nine specimens, four were chosen for ring counts and isotope analyses. "Annual" rings were counted and samples corresponding to the equivalent time of the bomb-14C peak were sampled. In addition a small subset of years within one tree specimen were sub

Mandibular ramus shape variation and ontogeny in Homo sapiens and Homo neanderthalensis.

PubMed

Terhune, Claire E; Ritzman, Terrence B; Robinson, Chris A

2018-04-27

As the interface between the mandible and cranium, the mandibular ramus is functionally significant and its morphology has been suggested to be informative for taxonomic and phylogenetic analyses. In primates, and particularly in great apes and humans, ramus morphology is highly variable, especially in the shape of the coronoid process and the relationship of the ramus to the alveolar margin. Here we compare ramus shape variation through ontogeny in Homo neanderthalensis to that of modern and fossil Homo sapiens using geometric morphometric analyses of two-dimensional semilandmarks and univariate measurements of ramus angulation and relative coronoid and condyle height. Results suggest that ramus, especially coronoid, morphology varies within and among subadult and adult modern human populations, with the Alaskan Inuit being particularly distinct. We also identify significant differences in overall anterosuperior ramus and coronoid shapes between H. sapiens and H. neanderthalensis, both in adults and throughout ontogeny. These shape differences are subtle, however, and we therefore suggest caution when using ramus morphology to diagnose group membership for individual specimens of these taxa. Furthermore, we argue that these morphologies are unlikely to be representative of differences in masticatory biomechanics and/or paramasticatory behaviors between Neanderthals and modern humans, as has been suggested by previous authors. Assessments of ontogenetic patterns of shape change reveal that the typical Neanderthal ramus morphology is established early in ontogeny, and there is little evidence for divergent postnatal ontogenetic allometric trajectories between Neanderthals and modern humans as a whole. This analysis informs our understanding of intraspecific patterns of mandibular shape variation and ontogeny in H. sapiens and can shed further light on overall developmental and life history differences between H. sapiens and H. neanderthalensis. Copyright �

Levantine cranium from Manot Cave (Israel) foreshadows the first European modern humans.

PubMed

Hershkovitz, Israel; Marder, Ofer; Ayalon, Avner; Bar-Matthews, Miryam; Yasur, Gal; Boaretto, Elisabetta; Caracuta, Valentina; Alex, Bridget; Frumkin, Amos; Goder-Goldberger, Mae; Gunz, Philipp; Holloway, Ralph L; Latimer, Bruce; Lavi, Ron; Matthews, Alan; Slon, Viviane; Mayer, Daniella Bar-Yosef; Berna, Francesco; Bar-Oz, Guy; Yeshurun, Reuven; May, Hila; Hans, Mark G; Weber, Gerhard W; Barzilai, Omry

2015-04-09

A key event in human evolution is the expansion of modern humans of African origin across Eurasia between 60 and 40 thousand years (kyr) before present (bp), replacing all other forms of hominins. Owing to the scarcity of human fossils from this period, these ancestors of all present-day non-African modern populations remain largely enigmatic. Here we describe a partial calvaria, recently discovered at Manot Cave (Western Galilee, Israel) and dated to 54.7 ± 5.5 kyr bp (arithmetic mean ± 2 standard deviations) by uranium-thorium dating, that sheds light on this crucial event. The overall shape and discrete morphological features of the Manot 1 calvaria demonstrate that this partial skull is unequivocally modern. It is similar in shape to recent African skulls as well as to European skulls from the Upper Palaeolithic period, but different from most other early anatomically modern humans in the Levant. This suggests that the Manot people could be closely related to the first modern humans who later successfully colonized Europe. Thus, the anatomical features used to support the 'assimilation model' in Europe might not have been inherited from European Neanderthals, but rather from earlier Levantine populations. Moreover, at present, Manot 1 is the only modern human specimen to provide evidence that during the Middle to Upper Palaeolithic interface, both modern humans and Neanderthals contemporaneously inhabited the southern Levant, close in time to the likely interbreeding event with Neanderthals.

Early modern human diversity suggests subdivided population structure and a complex out-of-Africa scenario

PubMed Central

Gunz, Philipp; Bookstein, Fred L.; Mitteroecker, Philipp; Stadlmayr, Andrea; Seidler, Horst; Weber, Gerhard W.

2009-01-01

The interpretation of genetic evidence regarding modern human origins depends, among other things, on assessments of the structure and the variation of ancient populations. Because we lack genetic data from the time when the first anatomically modern humans appeared, between 200,000 and 60,000 years ago, instead we exploit the phenotype of neurocranial geometry to compare the variation in early modern human fossils with that in other groups of fossil Homo and recent modern humans. Variation is assessed as the mean-squared Procrustes distance from the group average shape in a representation based on several hundred neurocranial landmarks and semilandmarks. We find that the early modern group has more shape variation than any other group in our sample, which covers 1.8 million years, and that they are morphologically similar to recent modern humans of diverse geographically dispersed populations but not to archaic groups. Of the currently competing models of modern human origins, some are inconsistent with these findings. Rather than a single out-of-Africa dispersal scenario, we suggest that early modern humans were already divided into different populations in Pleistocene Africa, after which there followed a complex migration pattern. Our conclusions bear implications for the inference of ancient human demography from genetic models and emphasize the importance of focusing research on those early modern humans, in particular, in Africa. PMID:19307568

Molecular and isotopic composition of lipids in modern and fossil bivalve shells: Records of paleoenvironmental change?

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

CoBabe, E.A.

1995-12-31

Suites of lipids residing in situ in modern and fossil bivalve shells offer new possibilities for the study of paleoecology and paleoclimatology. Distributions of carbon isotopic compositions of modem shell lipids suggests that many of these compounds, including alkanes, sterols, fatty acids, ketones and phytadienes, are derived from the bivalves and not directly from the surrounding environment. The occurrence of fatty acids in modem and fossil shell material opens up the possibility that saturation levels of these compounds may be used as paleothermometers. To date, the utility of fatty acids in paleoclimate studies has been limited because of the swiftmore » breakdown of these compounds in sediment. However, initial results indicate that fatty acids in bivalve shells retain their original structure for at least several million years. Comparison of modem bivalve shell fatty acids from tropical, temperate and polar nearshore marine systems will be presented, along with analogous fossil data.« less

Developing Age Models to Utilize High Arctic Coastal Sediments for Paleoclimate Research: Results from the Colville Delta and Simpson Lagoon, Alaska

NASA Astrophysics Data System (ADS)

Miller, A. J.; Allison, M. A.; Bianchi, T. S.; Marcantonio, F.

2012-12-01

Sediment cores collected from Simpson Lagoon on the inner Beaufort Sea shelf adjacent to the Colville River delta, AK are being utilized to develop new, high-resolution (sub-decadal scale) archives of the 0-3,000 year Arctic paleoclimate record necessary to assess natural and anthropogenic climate variability. An imperative first step for developing a new paleoclimate archive is to establish methodologies for constraining the age-depth relationship. Naturally occurring and bomb-produced radioisotopes have been utilized in sediments to constrain downcore variability of accumulation rates on 100-103 y timescales, but this methodology is complicated by low activities of many of these tracers at high latitudes. The present study utilizes the combination of a (1) multi-tracer approach and a (2) tailored measurement strategy to overcome this limitation. 210Pb and 137Cs analyses were conducted on the fine (<32μm) sediment fraction to maximize measurable activity and to minimize radioisotope activity variability resulting from changes in grain size: 137Cs geochronologies proved more reliable in this setting and revealed mm/y sediment accumulation in the lagoon. To corroborate the 137Cs results, 239,240Pu activities were analyzed for selected sites using ICP-MS which has ultra-low detection limits, and yielded accumulation rates that matched the Cs geochronology. Age model development for the remainder of the core lengths (>~100 y in age) were completed using radiocarbon dating of benthic foraminifera tests, which proved the only datable in situ carbon available in this sediment archive. These dates have been used to constrain the ages of acoustic reflectors in CHIRP subbottom seismic records collected from the lagoon. Using this age control, spatial patterns of lagoonal sediment accumulation over the last ~3 ky were derived from the CHIRP data. Two depocenters are identified and validate combining age-dated coring with high-resolution seismic profiling to identify areas

Implementation of higher-order vertical finite elements in ISSM v4.13 for improved ice sheet flow modeling over paleoclimate timescales

NASA Astrophysics Data System (ADS)

Cuzzone, Joshua K.; Morlighem, Mathieu; Larour, Eric; Schlegel, Nicole; Seroussi, Helene

2018-05-01

Paleoclimate proxies are being used in conjunction with ice sheet modeling experiments to determine how the Greenland ice sheet responded to past changes, particularly during the last deglaciation. Although these comparisons have been a critical component in our understanding of the Greenland ice sheet sensitivity to past warming, they often rely on modeling experiments that favor minimizing computational expense over increased model physics. Over Paleoclimate timescales, simulating the thermal structure of the ice sheet has large implications on the modeled ice viscosity, which can feedback onto the basal sliding and ice flow. To accurately capture the thermal field, models often require a high number of vertical layers. This is not the case for the stress balance computation, however, where a high vertical resolution is not necessary. Consequently, since stress balance and thermal equations are generally performed on the same mesh, more time is spent on the stress balance computation than is otherwise necessary. For these reasons, running a higher-order ice sheet model (e.g., Blatter-Pattyn) over timescales equivalent to the paleoclimate record has not been possible without incurring a large computational expense. To mitigate this issue, we propose a method that can be implemented within ice sheet models, whereby the vertical interpolation along the z axis relies on higher-order polynomials, rather than the traditional linear interpolation. This method is tested within the Ice Sheet System Model (ISSM) using quadratic and cubic finite elements for the vertical interpolation on an idealized case and a realistic Greenland configuration. A transient experiment for the ice thickness evolution of a single-dome ice sheet demonstrates improved accuracy using the higher-order vertical interpolation compared to models using the linear vertical interpolation, despite having fewer degrees of freedom. This method is also shown to improve a model's ability to capture sharp

Religion, Modernity and Social Rights in European Education

ERIC Educational Resources Information Center

Zambeta, Evie

2008-01-01

Religion, as social construct and institutional reality, has played a pivotal role in shaping European societies. In spite of the impact of Enlightenment theories in the formation of European modernity, institutionalized religions and established churches have managed to maintain their influence in the public domain. Educational systems, the par…

Autogenic geomorphic processes determine the resolution and fidelity of terrestrial paleoclimate records.

PubMed

Foreman, Brady Z; Straub, Kyle M

2017-09-01

Terrestrial paleoclimate records rely on proxies hosted in alluvial strata whose beds are deposited by unsteady and nonlinear geomorphic processes. It is broadly assumed that this renders the resultant time series of terrestrial paleoclimatic variability noisy and incomplete. We evaluate this assumption using a model of oscillating climate and the precise topographic evolution of an experimental alluvial system. We find that geomorphic stochasticity can create aliasing in the time series and spurious climate signals, but these issues are eliminated when the period of climate oscillation is longer than a key time scale of internal dynamics in the geomorphic system. This emergent autogenic geomorphic behavior imparts regularity to deposition and represents a natural discretization interval of the continuous climate signal. We propose that this time scale in nature could be in excess of 10 4 years but would still allow assessments of the rates of climate change at resolutions finer than the existing age model techniques in isolation.

Autogenic geomorphic processes determine the resolution and fidelity of terrestrial paleoclimate records

PubMed Central

Foreman, Brady Z.; Straub, Kyle M.

2017-01-01

Terrestrial paleoclimate records rely on proxies hosted in alluvial strata whose beds are deposited by unsteady and nonlinear geomorphic processes. It is broadly assumed that this renders the resultant time series of terrestrial paleoclimatic variability noisy and incomplete. We evaluate this assumption using a model of oscillating climate and the precise topographic evolution of an experimental alluvial system. We find that geomorphic stochasticity can create aliasing in the time series and spurious climate signals, but these issues are eliminated when the period of climate oscillation is longer than a key time scale of internal dynamics in the geomorphic system. This emergent autogenic geomorphic behavior imparts regularity to deposition and represents a natural discretization interval of the continuous climate signal. We propose that this time scale in nature could be in excess of 104 years but would still allow assessments of the rates of climate change at resolutions finer than the existing age model techniques in isolation. PMID:28924607

A Paleolatitude Calculator for Paleoclimate Studies

PubMed Central

van Hinsbergen, Douwe J. J.; de Groot, Lennart V.; van Schaik, Sebastiaan J.; Spakman, Wim; Bijl, Peter K.; Sluijs, Appy; Langereis, Cor G.; Brinkhuis, Henk

2015-01-01

Realistic appraisal of paleoclimatic information obtained from a particular location requires accurate knowledge of its paleolatitude defined relative to the Earth’s spin-axis. This is crucial to, among others, correctly assess the amount of solar energy received at a location at the moment of sediment deposition. The paleolatitude of an arbitrary location can in principle be reconstructed from tectonic plate reconstructions that (1) restore the relative motions between plates based on (marine) magnetic anomalies, and (2) reconstruct all plates relative to the spin axis using a paleomagnetic reference frame based on a global apparent polar wander path. Whereas many studies do employ high-quality relative plate reconstructions, the necessity of using a paleomagnetic reference frame for climate studies rather than a mantle reference frame appears under-appreciated. In this paper, we briefly summarize the theory of plate tectonic reconstructions and their reference frames tailored towards applications of paleoclimate reconstruction, and show that using a mantle reference frame, which defines plate positions relative to the mantle, instead of a paleomagnetic reference frame may introduce errors in paleolatitude of more than 15° (>1500 km). This is because mantle reference frames cannot constrain, or are specifically corrected for the effects of true polar wander. We used the latest, state-of-the-art plate reconstructions to build a global plate circuit, and developed an online, user-friendly paleolatitude calculator for the last 200 million years by placing this plate circuit in three widely used global apparent polar wander paths. As a novelty, this calculator adds error bars to paleolatitude estimates that can be incorporated in climate modeling. The calculator is available at www.paleolatitude.org. We illustrate the use of the paleolatitude calculator by showing how an apparent wide spread in Eocene sea surface temperatures of southern high latitudes may be in

A Paleolatitude Calculator for Paleoclimate Studies.

PubMed

van Hinsbergen, Douwe J J; de Groot, Lennart V; van Schaik, Sebastiaan J; Spakman, Wim; Bijl, Peter K; Sluijs, Appy; Langereis, Cor G; Brinkhuis, Henk

2015-01-01

Realistic appraisal of paleoclimatic information obtained from a particular location requires accurate knowledge of its paleolatitude defined relative to the Earth's spin-axis. This is crucial to, among others, correctly assess the amount of solar energy received at a location at the moment of sediment deposition. The paleolatitude of an arbitrary location can in principle be reconstructed from tectonic plate reconstructions that (1) restore the relative motions between plates based on (marine) magnetic anomalies, and (2) reconstruct all plates relative to the spin axis using a paleomagnetic reference frame based on a global apparent polar wander path. Whereas many studies do employ high-quality relative plate reconstructions, the necessity of using a paleomagnetic reference frame for climate studies rather than a mantle reference frame appears under-appreciated. In this paper, we briefly summarize the theory of plate tectonic reconstructions and their reference frames tailored towards applications of paleoclimate reconstruction, and show that using a mantle reference frame, which defines plate positions relative to the mantle, instead of a paleomagnetic reference frame may introduce errors in paleolatitude of more than 15° (>1500 km). This is because mantle reference frames cannot constrain, or are specifically corrected for the effects of true polar wander. We used the latest, state-of-the-art plate reconstructions to build a global plate circuit, and developed an online, user-friendly paleolatitude calculator for the last 200 million years by placing this plate circuit in three widely used global apparent polar wander paths. As a novelty, this calculator adds error bars to paleolatitude estimates that can be incorporated in climate modeling. The calculator is available at www.paleolatitude.org. We illustrate the use of the paleolatitude calculator by showing how an apparent wide spread in Eocene sea surface temperatures of southern high latitudes may be in part

The Power of Cooperation in International Paleoclimate Science: Examples from the PAGES 2k Network and the Ocean2k Working Group

NASA Astrophysics Data System (ADS)

Addison, J. A.

2015-12-01

The Past Global Changes (PAGES) project of IGBP and Future Earth supports research to understand the Earth's past environment to improve future climate predictions and inform strategies for sustainability. Within this framework, the PAGES 2k Network was established to provide a focus on the past 2000 years, a period that encompasses Medieval Climate Anomaly warming, Little Ice Age cooling, and recent anthropogenically-forced climate change. The results of these studies are used for testing earth system models, and for understanding decadal- to centennial-scale variability, which is needed for long-term planning. International coordination and cooperation among the nine regional Working Groups that make up the 2k Network has been critical to the success of PAGES 2k. The collaborative approach is moving toward scientific achievements across the regional groups, including: (i) the development of a community-driven open-access proxy climate database; (ii) integration of multi-resolution proxy records; (iii) development of multivariate climate reconstructions; and (iv) a leap forward in the spatial resolution of paleoclimate reconstructions. The last addition to the 2k Network, the Ocean2k Working Group has further innovated the collaborative approach by: (1) creating an open, receptive environment to discuss ideas exclusively in the virtual space; (2) employing an array of real-time collaborative software tools to enable communication, group document writing, and data analysis; (3) consolidating executive leadership teams to oversee project development and manage grassroots-style volunteer pools; and (4) embracing the value-added role that international and interdisciplinary science can play in advancing paleoclimate hypotheses critical to understanding future change. Ongoing efforts for the PAGES 2k Network are focused on developing new standards for data quality control and archiving. These tasks will provide the foundation for new and continuing "trans-regional" 2k

Intra-individual metameric variation expressed at the enamel-dentine junction of lower post-canine dentition of South African fossil hominins and modern humans.

PubMed

Pan, Lei; Thackeray, John Francis; Dumoncel, Jean; Zanolli, Clément; Oettlé, Anna; de Beer, Frikkie; Hoffman, Jakobus; Duployer, Benjamin; Tenailleau, Christophe; Braga, José

2017-08-01

The aim of this study is to compare the degree and patterning of inter- and intra-individual metameric variation in South African australopiths, early Homo and modern humans. Metameric variation likely reflects developmental and taxonomical issues, and could also be used to infer ecological and functional adaptations. However, its patterning along the early hominin postcanine dentition, particularly among South African fossil hominins, remains unexplored. Using microfocus X-ray computed tomography (µXCT) and geometric morphometric tools, we studied the enamel-dentine junction (EDJ) morphology and we investigated the intra- and inter-individual EDJ metameric variation among eight australopiths and two early Homo specimens from South Africa, as well as 32 modern humans. Along post-canine dentition, shape changes between metameres represented by relative positions and height of dentine horns, outlines of the EDJ occlusal table are reported in modern and fossil taxa. Comparisons of EDJ mean shapes and multivariate analyses reveal substantial variation in the direction and magnitude of metameric shape changes among taxa, but some common trends can be found. In modern humans, both the direction and magnitude of metameric shape change show increased variability in M 2 -M 3 compared to M 1 -M 2 . Fossil specimens are clustered together showing similar magnitudes of shape change. Along M 2 -M 3 , the lengths of their metameric vectors are not as variable as those of modern humans, but they display considerable variability in the direction of shape change. The distalward increase of metameric variation along the modern human molar row is consistent with the odontogenetic models of molar row structure (inhibitory cascade model). Though much remains to be tested, the variable trends and magnitudes in metamerism in fossil hominins reported here, together with differences in the scale of shape change between modern humans and fossil hominins may provide valuable information

The language of modern medicine: it's all Greek to me.

PubMed

Lewis, Kristopher N

2004-01-01

The Greek language has shaped and formed the lexicon of modern medicine. Although medical terminology may seem complex and difficult to master, the clarity and functionality of this language owe a great debt to the tongue of the classical Greeks.

Shaping metallic glasses by electromagnetic pulsing

PubMed Central

Kaltenboeck, Georg; Demetriou, Marios D.; Roberts, Scott; Johnson, William L.

2016-01-01

With damage tolerance rivalling advanced engineering alloys and thermoplastic forming capabilities analogous to conventional plastics, metallic glasses are emerging as a modern engineering material. Here, we take advantage of their unique electrical and rheological properties along with the classic Lorentz force concept to demonstrate that electromagnetic coupling of electric current and a magnetic field can thermoplastically shape a metallic glass without conventional heating sources or applied mechanical forces. Specifically, we identify a process window where application of an electric current pulse in the presence of a normally directed magnetic field can ohmically heat a metallic glass to a softened state, while simultaneously inducing a large enough magnetic body force to plastically shape it. The heating and shaping is performed on millisecond timescales, effectively bypassing crystallization producing fully amorphous-shaped parts. This electromagnetic forming approach lays the groundwork for a versatile, time- and energy-efficient manufacturing platform for ultrastrong metals. PMID:26853460

Shape Ontogeny of the Distal Femur in the Hominidae with Implications for the Evolution of Bipedality

PubMed Central

Tallman, Melissa

2016-01-01

Heterochrony has been invoked to explain differences in the morphology of modern humans as compared to other great apes. The distal femur is one area where heterochrony has been hypothesized to explain morphological differentiation among Plio-Pleistocene hominins. This hypothesis is evaluated here using geometric morphometric data to describe the ontogenetic shape trajectories of extant hominine distal femora and place Plio-Pleistocene hominins within that context. Results of multivariate statistical analyses showed that in both Homo and Gorilla, the shape of the distal femur changes significantly over the course of development, whereas that of Pan changes very little. Development of the distal femur of Homo is characterized by an elongation of the condyles, and a greater degree of enlargement of the medial condyle relative to the lateral condyle, whereas Gorilla are characterized by a greater degree of enlargement of the lateral condyle, relative to the medial. Early Homo and Australopithecus africanus fossils fell on the modern human ontogenetic shape trajectory and were most similar to either adult or adolescent modern humans while specimens of Australopithecus afarensis were more similar to Gorilla/Pan. These results indicate that shape differences among the distal femora of Plio-Pleistocene hominins and humans cannot be accounted for by heterochrony alone; heterochrony could explain a transition from the distal femoral shape of early Homo/A. africanus to modern Homo, but not a transition from A. afarensis to Homo. That change could be the result of genetic or epigenetic factors. PMID:26886416

A modern pollen-climate dataset from the Darjeeling area, eastern Himalaya: Assessing its potential for past climate reconstruction

NASA Astrophysics Data System (ADS)

Ghosh, Ruby; Bruch, Angela A.; Portmann, Felix; Bera, Subir; Paruya, Dipak Kumar; Morthekai, P.; Ali, Sheikh Nawaz

2017-10-01

Relying on the ability of pollen assemblages to differentiate among elevationally stratified vegetation zones, we assess the potential of a modern pollen-climate dataset from the Darjeeling area, eastern Himalaya, in past climate reconstructions. The dataset includes 73 surface samples from 25 sites collected from a c. 130-3600 m a.s.l. elevation gradient along a horizontal distance of c. 150 km and 124 terrestrial pollen taxa, which are analysed with respect to various climatic and environmental variables such as mean annual temperature (MAT), mean annual precipitation (MAP), mean temperature of coldest quarter (MTCQ), mean temperature of warmest quarter (MTWQ), mean precipitation of driest quarter (MPDQ), mean precipitation of wettest quarter (MPWQ), AET (actual evapotranspiration) and MI (moisture index). To check the reliability of the modern pollen-climate relationships different ordination methods are employed and subsequently tested with Huisman-Olff-Fresco (HOF) models. A series of pollen-climate parameter transfer functions using weighted-averaging regression and calibration partial least squares (WA-PLS) models are developed to reconstruct past climate changes from modern pollen data, and have been cross-validated. Results indicate that three of the environmental variables i.e., MTCQ, MPDQ and MI have strong potential for past climate reconstruction based on the available surface pollen dataset. The potential of the present modern pollen-climate relationship for regional quantitative paleoclimate reconstruction is further tested on a Late Quaternary fossil pollen profile from the Darjeeling foothill region with previously reconstructed and quantified climate. The good agreement with existing data allows for new insights in the hydroclimatic conditions during the Last glacial maxima (LGM) with (winter) temperature being the dominant controlling factor for glacial changes during the LGM in the eastern Himalaya.

Modern Marriage, Men’s Extramarital Sex, and HIV Risk in Southeastern Nigeria

PubMed Central

Smith, Daniel Jordan

2007-01-01

For women in Nigeria, as in many settings, simply being married can contribute to the risk of contracting HIV. I studied men’s extramarital sexual behavior in the context of modern marriage in southeastern Nigeria. The results indicate that the social organization of infidelity is shaped by economic inequality, aspirations for modern lifestyles, gender disparities, and contradictory moralities. It is men’s anxieties and ambivalence about masculinity, sexual morality, and social reputation in the context of seeking modern lifestyles—rather than immoral sexual behavior and traditional culture—that exacerbate the risks of HIV/AIDS. PMID:17463366

Paleoclimate reconstruction along the Pole-Equator-Pole transect of the Americas (PEP 1)

USGS Publications Warehouse

Markgraf, Vera; Baumgartner, T.R.; Bradbury, J.P.; Diaz, Henry F.; Dunbar, R.B.; Luckman, B.H.; Seltzer, G.O.; Swetnam, T.W.; Villalba, R.

2000-01-01

Examples are presented of inter-hemispheric comparison of instrumental climate and paleoclimate proxy records from the Americas for different temporal scales. Despite a certain symmetry of seasonal precipitation patterns along the PEP I transect, decadal variability of winter precipitation shows different characteristics in terms of amplitude and frequency in both the last 100 and last 1000 years. Such differences in variability are also seen in a comparison of time series of different El Nino/Southern Oscillation proxy records from North and South America, however, these differences do not appear to affect the spatial correlation with Pacific sea surface temperature patterns. Local and regional differences in response to climate change are even more pronounced for records with lower temporal resolution, and inter-hemispheric synchroneity may or may not be indicative of the same forcing. This aspect is illustrated in an inter-hemispheric comparison of the last 1000 years of glacier variability, and of the full- and lateglacial lake level history.

Recent eolian activity and paleoclimate fluctuations in the Ferris Lost Soldier Area, South-Central Wyoming

NASA Astrophysics Data System (ADS)

Gaylord, D. R.

1983-09-01

The Ferris Dune Fields were examined. Sand dunes are especially valuable in paleoclimate reconstructions because they: (1) bury and preserve datable materials and artifacts; (2) respond to even subtle changes in wind velocity and direction as reflected both in external morphology and internal structures; and (3) remain unconsolidated, making them amenable to easy textural and compositional examination. The valley of Clear Creek in the Ferris Dunes reveals a relatively continuous Holocene section of interbedded dune and interdunal pond deposits. Radiocarbon dates from the interdunal pond strata at Clear Creek, theoretical sand dune migration rates, compositional analysis of periglacial sand wedges, and relative dating of actively migrating parabolic dunes reveals a general sequence of geologic-climatic events that affected the Ferris-Lost Soldier area. The most recent major reactivaton of dunes occurred approximately 290 years ago.

Correlations between Climate Change and the Modern European Construction

NASA Astrophysics Data System (ADS)

Gumińska, Anna

2017-10-01

The aim of the study was to analyze the links between climate change and the way modern cities are structured and responded to climate change. How do these changes affect building materials and technologies, or does climate change affect the type of technology and materials used? The most important results are the effects of analysing selected examples of a modern European building, the use of materials and technology, the adaptation of buildings to the changing climate. Selected examples of contemporary architecture from Germany, Italy and Denmark, Norway and Sweden. There are also examples in photographic documentation. The most important criteria affecting the objects are elements that shape the changing climate, as well as existing legal and technical requirements. The main conclusion was that modern urban space is adapted to the changing climate. Unprecedented climatic phenomena in this area: intense and sudden rain, snow, floods, strong winds, abundant sunshine, high temperature changes, greenhouse effect of the city - “island heat”, atmospheric pollution. Building materials and technologies contribute to the optimal conservation of natural resources, buildings are shaped in such a way as to ensure safety, resilience and environmental protection. However, there is still a need for continuous monitoring of climate change, criteria affecting the design and construction of urban and central facilities. Key words: energy efficiency, renewable energy, climate change, contemporary architecture.

Philosophical aspects of modern cosmology

NASA Astrophysics Data System (ADS)

Zinkernagel, Henrik

2014-05-01

Cosmology is the attempt to understand in scientific terms the structure and evolution of the universe as a whole. This ambition has been with us since the ancient Greeks, even if the developments in modern cosmology have provided a picture of the universe dramatically different from that of Pythagoras, Plato and Aristotle. The cosmological thinking of these figures, e.g. the belief in uniform circular motion of the heavens, was closely related to their philosophical ideas, and it shaped the field of cosmology at least up to the times of Copernicus and Kepler.

European early modern humans and the fate of the Neandertals

PubMed Central

Trinkaus, Erik

2007-01-01

A consideration of the morphological aspects of the earliest modern humans in Europe (more than ≈33,000 B.P.) and the subsequent Gravettian human remains indicates that they possess an anatomical pattern congruent with the autapomorphic (derived) morphology of the earliest (Middle Paleolithic) African modern humans. However, they exhibit a variable suite of features that are either distinctive Neandertal traits and/or plesiomorphic (ancestral) aspects that had been lost among the African Middle Paleolithic modern humans. These features include aspects of neurocranial shape, basicranial external morphology, mandibular ramal and symphyseal form, dental morphology and size, and anteroposterior dental proportions, as well as aspects of the clavicles, scapulae, metacarpals, and appendicular proportions. The ubiquitous and variable presence of these morphological features in the European earlier modern human samples can only be parsimoniously explained as a product of modest levels of assimilation of Neandertals into early modern human populations as the latter dispersed across Europe. This interpretation is in agreement with current analyses of recent and past human molecular data. PMID:17452632

Three-dimensional Procrustes analysis of modern human craniofacial form.

PubMed

Badawi-Fayad, Jackie; Cabanis, Emmanuel-Alain

2007-03-01

The objective of this study was to analyze modern human craniofacial form using 3D Procrustes superimposition in order to establish a reference model and validate it on computed tomography (CT). The sample consists of 136 specimens from five modern human regional groups. Thirty-three craniofacial landmark coordinates have been recorded using a Microscribe and calculated on CT scans for five crania from the sample. Procrustes superimposition has been performed to calculate the mean shape, and a discriminant analysis has also been carried out to estimate the variability of shape. The results show that the repeatability of measurements made on CT and on Microscribe is excellent (R = 0.99). There is no major distinctiveness in the craniofacial shape; however, discriminant function 1 separates out the European crania from the others, especially African and American. It includes the width and the length of the face, the flatness of the upper face, the prognathism of the maxilla, as well as the length and the inclination of the palate. The width of the maxilla and the palate do not show a great variability. This may be the common invariant feature responsible for the alignment of the teeth in all specimens. It may correspond to functional patterns related to masticatory constraints manifested by the important interproximal and occlusal dental wear in all specimens. This study confirms the high accuracy of measurements made on CT scan and the importance of geometric morphometrics, which provides an accurate characterization of the overall craniofacial shape and its variation within the entire population.

Facial Orientation and Facial Shape in Extant Great Apes: A Geometric Morphometric Analysis of Covariation

PubMed Central

Neaux, Dimitri; Guy, Franck; Gilissen, Emmanuel; Coudyzer, Walter; Vignaud, Patrick; Ducrocq, Stéphane

2013-01-01

The organization of the bony face is complex, its morphology being influenced in part by the rest of the cranium. Characterizing the facial morphological variation and craniofacial covariation patterns in extant hominids is fundamental to the understanding of their evolutionary history. Numerous studies on hominid facial shape have proposed hypotheses concerning the relationship between the anterior facial shape, facial block orientation and basicranial flexion. In this study we test these hypotheses in a sample of adult specimens belonging to three extant hominid genera (Homo, Pan and Gorilla). Intraspecific variation and covariation patterns are analyzed using geometric morphometric methods and multivariate statistics, such as partial least squared on three-dimensional landmarks coordinates. Our results indicate significant intraspecific covariation between facial shape, facial block orientation and basicranial flexion. Hominids share similar characteristics in the relationship between anterior facial shape and facial block orientation. Modern humans exhibit a specific pattern in the covariation between anterior facial shape and basicranial flexion. This peculiar feature underscores the role of modern humans' highly-flexed basicranium in the overall integration of the cranium. Furthermore, our results are consistent with the hypothesis of a relationship between the reduction of the value of the cranial base angle and a downward rotation of the facial block in modern humans, and to a lesser extent in chimpanzees. PMID:23441232

Maternity and modernity: Soviet women teachers and the contradictions of Stalinism.

PubMed

Ewing, E Thomas

2010-01-01

This article explores how Soviet political identities were shaped by maternal concerns and how mothers' practices were shaped by the professional obligations of teaching in the Stalinist 1930s. Exploring an occupation that became more female as it became more modern, a professional identity that denied or constrained female sexuality, a calling devoted to children that left little time for motherhood, and a social role that assigned the task of socialization to women who did not enjoy full civic rights, this study examines the ways that Stalinist mother teachers assumed a distinct identity through their practices at school and in the family. Identifying specific moments where these questions became public focuses attention on maternity and modernity in ways that illustrate how fully Stalinist repression penetrated into society and how the Soviet people perceived, accepted, challenged, or otherwise mediated the contradictory nature of these political forces.

Origins of the historiography of modern Greek science.

PubMed

Patiniotis, Manolis

2008-01-01

The purpose of the paper is to examine how Greek historians account for the presence of modern scientific ideas in the intellectual environment of eighteenth-century Greek-speaking society. It will also discuss the function of the history of modern Greek science in the context of Greek national historiography. As will be shown, the history of modem Greek science spent most of its life under the shadow of the history of ideas. Despite its seemingly secondary role, however, it occupied a distinctive place within national historiography because it formed the ground upon which different perceptions of the country's European identity converged. In this respect, one of the main goals of this paper is to outline the particular ideological presumptions, which shaped the historiography of modern Greek science under different historical circumstances. At the end an attempt will be made to articulate a viewpoint more in tandem with the recent methodological developments in the history of science.

Conjugal intimacy, gender and modernity in contemporary China.

PubMed

Liu, Jieyu; Bell, Eona; Zhang, Jiayu

2017-12-15

The new generation of modernity theorists have forecast the democratization of gender relations within intimate relationships in late-modern times. Chinese society has undergone rapid and dramatic changes in its unique trajectory of political, social and economic reform. Using China as an example of a region which has been largely ignored in contemporary social theory, this article enters the debate to contest the extent to which conjugal relationships are democratized in line with modernity. We further test the assertion that modern marriages are characterized by increased self-disclosure and communication between partners. Data from a national survey on Chinese families is analysed in relation to the level of self-disclosure between husbands and wives; gender division of housework; household decision-making; and home ownership. We highlight the impact of gender, cohort and location (urban, rural or migrant) on experiences of modernity and draw attention to the material, social and cultural factors which continue to shape conjugal relations in contemporary Chinese society. Based on our findings, we contest the argument that disclosing intimacy between intimate partners is a defining characteristic of modern relationships, and suggest that other social factors may condition degrees of self-disclosure in marriage. Similarly, we question the extent to which heterosexual conjugal equality is attained: the cultural practices and values of patrilineal family organization, together with material circumstances, continue to influence marital relations in China. © London School of Economics and Political Science 2017.

Delineating modern variation from extinct morphology in the fossil record using shells of the Eastern Box Turtle (Terrapene carolina)

PubMed Central

2018-01-01

Characterization of morphological variation in the shells of extant Eastern Box Turtles, Terrapene carolina, provides a baseline for comparison to fossil populations. It also provides an example of the difficulties inherent to recognizing intraspecific diversity in the fossil record. The degree to which variation in fossils of T. carolina can be accommodated by extant variation in the species has been disagreed upon for over eighty years. Using morphometric analyses of the carapace, I address the relationship between modern and fossil T. carolina in terms of sexual dimorphism, geographic and subspecific variation, and allometric variation. Modern T. carolina display weak male-biased sexual size dimorphism. Sexual shape dimorphism cannot be reliably detected in the fossil record. Rather than a four-part subspecific division, patterns of geographic variation are more consistent with clinal variation between various regions in the species distribution. Allometric patterns are qualitatively similar to those documented in other emydid turtles and explain a significant amount of shape variation. When allometric patterns are accounted for, Holocene specimens are not significantly different from modern specimens. In contrast, several geologically older specimens have significantly different carapace shape with no modern analogue. Those large, fossilized specimens represent extinct variation occupying novel portions of morphospace. This study highlights the need for additional documentation of modern osteological variation that can be used to test hypotheses of intraspecific evolution in the fossil record. PMID:29513709

Late Pleistocene-Holocene paleoclimate in southwestern Brazilian Amazonia with basis on floristic changes interpreted from isotope data

NASA Astrophysics Data System (ADS)

Rossetti, D. F.; Cohen, M. C. L.; Pessenda, L. C. R.

2015-12-01

Previous late Quaternary paleoclimatic interpretations in Amazonia have considered fluctuating dry to wet episodes with changes from savanna to forest, a view that concurs with other proposals of undisturbed rainforest despite global oscillations. Most of this debate is based on pollen data, but such elements are scarce in Amazonian sedimentary records. This work interprets vegetation in the Late Pleistocene and Holocene in a southwestern Amazonia lowland using δ13C, δ15N, C/N integrated with geomorphology, sedimentology and radiocarbon dating. The goal was to reconstruct vegetation changes through time and analyze their relation to climate and sedimentary dynamics. Fluvial channel and floodplain deposits with phytoplankton, as well as C3 and C4 land plants, were recorded. Between 42,033-43,168 cal yr BP and 34,804-35,584 cal yr BP, C4 land plants increased as a result of a climate drier than todaýs. However, wet climate prevailed from this time-frame until the onset of the Last Glaciation Maximum. In the Pleistocene/Holocene transition, there was an increased contribution of C4 land plants potentially related to dry episodes. However, the increased contribution of this type of land plant is not synchronous with Holocene dry episodes previously documented for the Amazonian lowland. On the other hand, it is remarkable that the record of this plant type was verified only in sites with modern grassland confined to fluvial paleo-landforms. Thus, rather than due to a dry climatic episode, the recorded grassland expansion and its maintenance up to the present time in the studied sites is more likely associated with the evolution of depositional environments, being coincidental with the progressive abandonment of fluvial systems. An important conclusion derived from the present work is that great care must be placed when reconstructing late Quaternary paleoclimate in Amazonia based on changes in floristic patterns, as they may be also a response to sedimentary dynamics.

Neogene interaction of the westerlies and high topography north of the Plateau: Implications for Central Asia paleoclimate

NASA Astrophysics Data System (ADS)

Caves Rugenstein, J. K.; Bayshashov, B. U.; Zhamangara, A.; Ritch, A. J.; Ibarra, D. E.; Sjostrom, D. J.; Mix, H.; Winnick, M.; Chamberlain, C. P.

2017-12-01

The timing of high surface topography and the corresponding climatic impacts of the many high ranges north of the Tibetan Plateau, such as the Altai and Tian Shan, remain poorly constrained. Most Neogene reconstructions of Central Asia climate come from interior China, where the influences of Altai and Tian Shan uplift are difficult to deconvolve from effects due to Tibetan Plateau uplift and changes in global climate. We present a new pedogenic carbonate oxygen and carbon isotope record from terrestrial Neogene sediments of the Zaysan Basin in eastern Kazakhstan, which lies upwind of the Altai and Tian Shan, in contrast to the numerous paleoclimate records from interior China. The δ18O values of pedogenic carbonate exhibit a robust 4‰ decrease in the late Neogene—a trend that sharply contrasts with nearly all downwind records of δ18O from Central Asia. We attribute this decrease to the establishment of the modern seasonal precipitation regime whereby Kazakhstan receives the majority of its moisture in the spring and fall, which lowers the δ18O of pedogenic carbonates. The dominance of spring and fall precipitation in Kazakhstan results from the interaction of the mid-latitude jet with the high topography of the Altai and Tian Shan during its movement northward in spring and southward in fall. The late Miocene interaction of the jet with these actively uplifting northern Central Asia ranges reorganized Central Asia climate, establishing starkly different seasonal precipitation regimes, further drying interior China, and increasing the incidence of the lee cyclones that deposit dust on the Loess Plateau. To the south of the Zaysan Basin, earlier shifts in δ18O hint at early Neogene changes in climate attributable to a late Oligocene/early Miocene phase of uplift in the Tian Shan. We conclude that paleoclimatic changes in Central Asia in the Neogene are more tightly controlled by the interaction of the mid-latitude westerlies with the bounding ranges of

The Role of Genetic Drift in Shaping Modern Human Cranial Evolution: A Test Using Microevolutionary Modeling

PubMed Central

Smith, Heather F.

2011-01-01

The means by which various microevolutionary processes have acted in the past to produce patterns of cranial variation that characterize modern humans is not thoroughly understood. Applying a microevolutionary framework, within- and among-population variance/covariance (V/CV) structure was compared for several functional and developmental modules of the skull across a worldwide sample of modern humans. V/CV patterns in the basicranium, temporal bone, and face are proportional within and among groups, which is consistent with a hypothesis of neutral evolution; however, mandibular morphology deviated from this pattern. Degree of intergroup similarity in facial, temporal bone, and mandibular morphology is significantly correlated with geographic distance; however, much of the variance remains unexplained. These findings provide insight into the evolutionary history of modern human cranial variation by identifying signatures of genetic drift, gene flow, and migration and set the stage for inferences regarding selective pressures that early humans encountered since their initial migrations around the world. PMID:21461369

A new node on the SE Asian paleoclimate map: the alkaline crater lakes of central Myanmar

NASA Astrophysics Data System (ADS)

Smittenberg, Rienk H.; Chabangborn, Akkaneewut; Thu Aung, Lin; Fritz, Sherilyn; Wohlfarth, Barbara

2014-05-01

SE Asia is climatically a key region where the Asian monsoon system connects with the Indo-Pacific warm pool and from where much (latent) heat gets transported to higher latitudes. We recently obtained sediment cores from four crater lakes located in Central Myanmar, with the aim to further colour the still largely white space on the SE Asian paleoclimate map. The chain of volcanic craters extending northeast to southwest in the vicinity of the lower Chindwin River in central Myanmar have been known for a long time. These craters are aligned west of the Sagaing Fault, which is a continental transform fault between the Indian and Sunda continental plates. Four of the craters still contain lakes, while several of the smaller craters are drained and used for agriculture. The region has a tropical Savannah climate, with warm temperatures throughout the year. Precipitation is almost absent during the dry season but increases to an average monthly precipitation of 100-134 mm per month during the monsoon season (May through October). Three of the four lakes, named Twin Ywa (30 m depth), Twin Taung (60 m), and Twin Pyauk (8m), are highly alkaline (pH 10-11), support extensive cyanobacterial blooms and are anoxic below a few meters water depth. Their sediments are composed of highly organic and laminated algae gyttjas. The shallower (2m), oxic and more neutral (pH 7.5) Lake Leshe contains organic-lean clays but with clear variations in colour and bulk density that likely mark changes in humidity though time. The lake levels of the relatively small crater lakes are solely regulated by precipitation and evaporation, and their limnology and water isotope compositions are therefore sensitive to changes in monsoon intensity. We will present limnological data including water isotopic compositions, and initial bulk sedimentary data as well as preliminary age determinations. These will form the basis for more extensive multi-proxy analyses that should result in an improved insight

Coupling carbon isotopes with astrochronology and correlation techniques for Late Cretaceous chronostratigraphic refinement and paleoclimate reconstruction

NASA Astrophysics Data System (ADS)

Jones, M. M.; Sageman, B. B.; Meyers, S. R.

2016-12-01

Late Cretaceous carbon isotope ratios (δ13C) recorded in organic matter and marine carbonates preserve an archive of the global carbon cycle in a greenhouse climate state. Due to excellent connectivity among surface carbon reservoirs and the low residence time of carbon in them, excursions in the δ13C that record changes in fluxes serve as widely correlative chronostratigraphic markers. In this study, floating astronomical time scales (ATS) from an organic carbon-rich marine Turonian succession at Demerara Rise (tropical N. Atlantic) are combined with high-resolution δ13C chemostratigraphy to estimate CIE timing and duration for refinement of the geologic time scale. In addition, a Gaussian kernel smoothing technique for objective correlation of astronomically tuned δ13C records is developed. Correlation with three coeval Turonian sections (Western Interior Basin, Texas, & Europe) shows consistency in astronomical and radioisotopic time scale ages for CIEs. In particular, a mid-Turonian sea level fall is demonstrated to be synchronous within 100 ka uncertainty. Spectral analyses of δ13Corg, %TOC, %Carbonate, and C/N time series provide insights into astronomical forcings influencing paleoclimate and paleoceanographic conditions in the tropical proto-North Atlantic upwelling zone. The stable long eccentricity cycle ( 405 ka) is robustly recorded in all geochemical data, and has the highest amplitude in %TOC, %Carbonate, and C/N time series. However, δ13C from Demerara Rise is dominated by a 1 Myr cycle resembling long obliquity, suggesting a dynamic organic carbon reservoir and/or climate feedback originating in high-latitudes was prominent during the Turonian greenhouse carbon cycle. This investigation emphasizes δ13C chemostratigraphy and astrochronology are useful chronostratigraphic methods for importing high-resolution time control into disparate basins to answer questions regarding sea level records, paleoclimate, and mass extinction on a global scale

Using vegetation model-to-data comparisons to test the role of abiotic factors in the Neogene and Quaternary origins of modern C4 grasslands

NASA Astrophysics Data System (ADS)

Fox, D. L.; Strömberg, C.; Pau, S.; Taylor, L.; Lehmann, C.; Osborne, C.; Beerling, D. J.; Still, C. J.

2014-12-01

Grasslands dominated by taxa using the C4 photosynthetic pathway evolved on several continents during the Neogene and Quaternary, long after C4 photosynthesis first evolved among grasses. The histories of these ecosystems are relatively well documented in the geological record from stable carbon isotopes (fossil vertebrate herbivores, paleosols) and the plant microfossil record (pollen, phytoliths). The distinct biogeography and ecophysiology of modern C3 and C4 grasses have led to hypotheses explaining the origins of C4 grasslands in terms of long term changes in the Earth system such as increased aridity and decreasing atmospheric pCO2. However, proxies for key parameters of these hypotheses (e.g., temperature, precipitation, pCO2) are still in development, not yet widely applied, or remain contentious, so testing the hypotheses globally remains difficult. To understand better possible links between changes in the Earth system and the origin of C4 grasslands on different continents, we are undertaking a global scale comparison between observational records of C4 grass abundances in Miocene and Pliocene localities compiled from the literature, and three increasingly complex models of C4 dominance and abundance. The literature compilation comprises >2,600 δ13C values of both fossil vertebrates and of paleosol carbonates and >6,700 paleobotanical records. We are using paleoclimate output from the HadCM3L GCM over a range of pCO2 values for each epoch to model C4 dominance or abundance in grid cells as (Model 1) months per year exceeding the temperature at which net assimilation is greater for C4 than C3 photosynthesis (crossover temperature); (Model 2) the number of months per year exceeding the crossover temperature and having sufficient precipitation for growth (≥25 cm/yr; Collatz model); and (Model 3) the Sheffield Dynamic Global Vegetation Model (SDGVM), output from which includes biomass (g C/m2/yr) for distinct structural components (roots, stems, leaves

Using Foraminifera Shell Geochemistry to Test Proxies for Paleoclimate Reconstruction

NASA Astrophysics Data System (ADS)

Hudson, C. Y.; Herrmann, A. D.

2016-02-01

Previous research conducted on Foraminifera tests determined that the elemental concentrations of the shell reflect pH and salinity of the environment these organisms lived in. Changes in concentrations of Boron and Uranium were analyzed because they are both pH and salinity indicators. For this project, sand samples were gathered from two different stations along Terrebonne Bay in the Gulf of Mexico. Each station had a different depth and salinity. Alabaminella sp. were then separated from the sand sample. Foraminifera were analyzed using an LA-ICP-MS to determine if there were geochemical differences in the shells from different stations. If differences were determined to exist, then it would be possible to use these differences to reconstruct changes in past coastal environments. Because the depth and salinity at each Terrebonne station was different, it was expected that the geochemisty of the shells would also be different. It has been concluded that the Foraminifera shells from each station show no significant variation in their Boron and Uranium concentrations. Therefore, paleoclimate pH and salinity cannot be accurately reconstructed using these Foraminifera collected from Terrebonne Bay. The similarity of the geochemistries is likely due to the short distance between stations, allowing the Foraminifera to easily move from one location to another. Further tests can evaluate whether Foraminifera collected from stations farther apart do show the expected geochemical changes that result from different environments.

A Taxonomic Reduced-Space Pollen Model for Paleoclimate Reconstruction

NASA Astrophysics Data System (ADS)

Wahl, E. R.; Schoelzel, C.

2010-12-01

Paleoenvironmental reconstruction from fossil pollen often attempts to take advantage of the rich taxonomic diversity in such data. Here, a taxonomically "reduced-space" reconstruction model is explored that would be parsimonious in introducing parameters needing to be estimated within a Bayesian Hierarchical Modeling context. This work involves a refinement of the traditional pollen ratio method. This method is useful when one (or a few) dominant pollen type(s) in a region have a strong positive correlation with a climate variable of interest and another (or a few) dominant pollen type(s) have a strong negative correlation. When, e.g., counts of pollen taxa a and b (r >0) are combined with pollen types c and d (r <0) to form ratios of the form (a + b) / (a + b + c + d), an appropriate estimation form is the binomial logistic generalized linear model (GLM). The GLM can readily model this relationship in the forward form, pollen = g(climate), which is more physically realistic than inverse models often used in paleoclimate reconstruction [climate = f(pollen)]. The specification of the model is: rnum Bin(n,p), where E(r|T) = p = exp(η)/[1+exp(η)], and η = α + β(T); r is the pollen ratio formed as above, rnum is the ratio numerator, n is the ratio denominator (i.e., the sum of pollen counts), the denominator-specific count is (n - rnum), and T is the temperature at each site corresponding to a specific value of r. Ecological and empirical screening identified the model (Spruce+Birch) / (Spruce+Birch+Oak+Hickory) for use in temperate eastern N. America. α and β were estimated using both "traditional" and Bayesian GLM algorithms (in R). Although it includes only four pollen types, the ratio model yields more explained variation ( 80%) in the pollen-temperature relationship of the study region than a 64-taxon modern analog technique (MAT). Thus, the new pollen ratio method represents an information-rich, reduced space data model that can be efficiently employed in

The Effects of Different Electrode Types for Obtaining Surface Machining Shape on Shape Memory Alloy Using Electrochemical Machining

NASA Astrophysics Data System (ADS)

Choi, S. G.; Kim, S. H.; Choi, W. K.; Moon, G. C.; Lee, E. S.

2017-06-01

Shape memory alloy (SMA) is important material used for the medicine and aerospace industry due to its characteristics called the shape memory effect, which involves the recovery of deformed alloy to its original state through the application of temperature or stress. Consumers in modern society demand stability in parts. Electrochemical machining is one of the methods for obtained these stabilities in parts requirements. These parts of shape memory alloy require fine patterns in some applications. In order to machine a fine pattern, the electrochemical machining method is suitable. For precision electrochemical machining using different shape electrodes, the current density should be controlled precisely. And electrode shape is required for precise electrochemical machining. It is possible to obtain precise square holes on the SMA if the insulation layer controlled the unnecessary current between electrode and workpiece. If it is adjusting the unnecessary current to obtain the desired shape, it will be a great contribution to the medical industry and the aerospace industry. It is possible to process a desired shape to the shape memory alloy by micro controlling the unnecessary current. In case of the square electrode without insulation layer, it derives inexact square holes due to the unnecessary current. The results using the insulated electrode in only side show precise square holes. The removal rate improved in case of insulated electrode than others because insulation layer concentrate the applied current to the machining zone.

Testing the Reconstruction Potential for North Pacific Circulation Anomalies inside the TraCE-21ka Paleoclimate Simulation

NASA Astrophysics Data System (ADS)

Elison Timm, O.; Flamholtz, W. M.; Li, S.; Massa, C.; Beilman, D. W.

2016-12-01

The motivation for this study was sparked by the idea that paleoclimate temperature and precipitation proxies provide sufficient information to make inferences about extratropical atmospheric circulation changes over the North Pacific during the Holocene. Typical targets for the circulation reconstruction problem include the strength and position of the Aleutian Low and the storm tracks. The reconstruction problem was investigated under idealized conditions using model simulation results from the TraCE-21ka transient climate simulation (http://www.cgd.ucar.edu/ccr/TraCE/), which covers the Last Glacial Maximum to present. It is demonstrated that modes of variability found on interannual to multidecadal timescales during the preindustrial era provide inadequate pattern for reconstructing long-term mean changes during the past 22,000 years. Our circulation reconstruction target was the geopotential height field at 500hPa (Z500) over the North Pacific Ocean during winter. We applied a field reconstruction method using Maximum Covariance Analysis (MCA). The MCA was applied to Z500 and surface temperatures as predictor information. The MCA was given model data containing interannual to multidecadal variability from the pre-industrial climate (1000BP-900BP). We worked with ten leading MCA modes in the reconstruction, which can reproduce about 90% of the covariability during the preindustrial period. Within the model simulation, we validated the field reconstructions against the model's circulation states over the last 22,000 years. Spatial skill scores show that the reconstruction skill drops significantly prior to the late Holocene. Reasons for the loss of reconstruction skill are due to the fact that externally forced climate changes do not resemble the internal modes of variability and that covariance between circulation and temperatures on interannual-multidecadal time scales changes with the background climate state. However, the reconstruction can be improved by

The Growing Role of Private Giving in Financing the Modern University

ERIC Educational Resources Information Center

Speck, Bruce W.

2010-01-01

Increased use of private funds to support public higher education is essential, but private funding undoubtedly shapes the university in ways that challenge academic traditions, creating a new paradigm for financing the modern university. In this chapter, the author describes the three sources of funding for higher education: (1) tuition and fees;…

Cranial measures and ancient DNA both show greater similarity of Neandertals to recent modern Eurasians than to recent modern sub-Saharan Africans.

PubMed

Relethford, John H; Smith, Fred H

2018-05-01

Ancient DNA analysis has shown that present-day humans of Eurasian ancestry are more similar to Neandertals than are present-day humans of sub-Saharan African ancestry, reflecting interbreeding after modern humans first left Africa. We use craniometric data to test the hypothesis that the crania of recent modern humans show the same pattern. We computed Mahalanobis squared distances between a published Neandertal centroid based on 37 craniometric traits and each of 2,413 recent modern humans from the Howells global data set (N = 373 sub-Saharan Africans, N = 2,040 individuals of Eurasian descent). The average distance to the Neandertal centroid is significantly lower for Eurasian crania than for sub-Saharan African crania as expected from the findings of ancient DNA (p < 0.001). This result holds when examining distances for separate geographic regions of humans of Eurasian descent (Europeans, Asians, Australasians, Native Americans, and Pacific Islanders). Most of these results are also seen when examining distances partitioning size and shape variation. Our results show that the genetic difference in Neandertal ancestry seen in the DNA of present-day sub-Saharan Africans and Eurasians is also found in patterns of recent modern human craniometric variation. © 2018 Wiley Periodicals, Inc.

Pervasive genetic integration directs the evolution of human skull shape.

PubMed

Martínez-Abadías, Neus; Esparza, Mireia; Sjøvold, Torstein; González-José, Rolando; Santos, Mauro; Hernández, Miquel; Klingenberg, Christian Peter

2012-04-01

It has long been unclear whether the different derived cranial traits of modern humans evolved independently in response to separate selection pressures or whether they resulted from the inherent morphological integration throughout the skull. In a novel approach to this issue, we combine evolutionary quantitative genetics and geometric morphometrics to analyze genetic and phenotypic integration in human skull shape. We measured human skulls in the ossuary of Hallstatt (Austria), which offer a unique opportunity because they are associated with genealogical data. Our results indicate pronounced covariation of traits throughout the skull. Separate simulations of selection for localized shape changes corresponding to some of the principal derived characters of modern human skulls produced outcomes that were similar to each other and involved a joint response in all of these traits. The data for both genetic and phenotypic shape variation were not consistent with the hypothesis that the face, cranial base, and cranial vault are completely independent modules but relatively strongly integrated structures. These results indicate pervasive integration in the human skull and suggest a reinterpretation of the selective scenario for human evolution where the origin of any one of the derived characters may have facilitated the evolution of the others. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Preservation of carbonate clumped isotopes in sedimentary paleoclimate archives

NASA Astrophysics Data System (ADS)

Henkes, G. A.; Passey, B. H.; Grossman, E. L.; Shenton, B.; Perez-Huerta, A.

2014-12-01

Carbonate clumped isotope thermometry is increasingly used to reconstruct paleotemperatures of ancient terrestrial environments. One promising application is elucidating paleoelevation from carbonate archives such as paleosols, lacustrine marls, and fossil freshwater shells. Unlike conventional stable isotope approaches (e.g., mineral δ18O or δD), clumped isotope thermometry is independent of the isotopic composition of the precipitating waters and can therefore be used to reconstruct elevation by both the temperature-altitude relationship and the rainfall δ18O-altitude relationship. However, interpretation of clumped isotope data is not without its own complications. Like conventional stable isotopes, clumped isotope paleotemperatures can be effectively reset to warmer values by dissolution/reprecipitation-type diagenesis during sedimentary burial. It is also known that carbonate clumped isotope bonds (i.e., 13C-18O) are susceptible to 'reordering' in the solid mineral lattice at warmer burial temperatures, with laboratory studies of natural carbonates indicating activation of this phenomenon at temperatures as low as 100 °C over geologic timescales. A challenge in applying carbonate clumped isotope thermometry to natural samples is now evaluating terrestrial archives with respect to both types of alteration: 'open-system' alteration and 'closed-system' bond reordering. In this talk we will review our experimental efforts to constrain the kinetics of clumped isotope reordering, with relevance to low-temperature carbonates like fossil shells and early diagenetic minerals, and present new laboratory data that further inform our theoretical framework for the mechanism(s) of 13C-18O bond reordering. Together with traditional analytical and petrographic screening for recrystallization, empirical and laboratory studies of carbonate clumped isotope reordering represent the next steps in evaluating isotopic records of paleoclimate, paleobiology, and paleoelevation

On the co-creation of classical and modern physics.

PubMed

Staley, Richard

2005-12-01

While the concept of "classical physics" has long framed our understanding of the environment from which modern physics emerged, it has consistently been read back into a period in which the physicists concerned initially considered their work in quite other terms. This essay explores the shifting currency of the rich cultural image of the classical/ modern divide by tracing empirically different uses of "classical" within the physics community from the 1890s to 1911. A study of fin-de-siècle addresses shows that the earliest general uses of the concept proved controversial. Our present understanding of the term was in large part shaped by its incorporation (in different ways) within the emerging theories of relativity and quantum theory--where the content of "classical" physics was defined by proponents of the new. Studying the diverse ways in which Boltzmann, Larmor, Poincaré, Einstein, Minkowski, and Planck invoked the term "classical" will help clarify the critical relations between physicists' research programs and their use of worldview arguments in fashioning modern physics.

Traditional Chinese rehabilitative therapy in the process of modernization.

PubMed

Zhuo, D H

1988-01-01

In the past few years modalities of traditional Chinese rehabilitative therapy have changed from an experimental approach towards the shaping of a modernized and scientific system. The landmark of this process is characterized by adoption of scientific methods in the appraisal of efficacy, provision of experimental evidence to unveil the mechanisms for the treatments and development of new modalities by innovation with modern technology. Recent advances in clinical and experimental studies on acupuncture, Chinese massage and manipulation, qigong, and Tai Ji exercise are reviewed, with a focus on new findings in physiological mechanisms and effects on anti-senility. Comments are made on new modalities such as 'physical therapy on acupoints'. Progress in the use of qigong (meditation therapy) in tapping mental potentials and remediating mental deficiency is also reported.

Climate regime shifts in paleoclimate time series from the Yucatán Peninsula: from the Preclassic to Classic period

NASA Astrophysics Data System (ADS)

Polanco Martínez, Josue M.; Medina-Elizalde, Martin; Burns, Stephen J.; Jiang, Xiuyang; Shen, Chuan-Chou

2015-04-01

It has been widely accepted by the paleoclimate and archaeology communities that extreme climate events (especially droughts) and past climate change played an important role in the cultural changes that occurred in at least some parts of the Maya Lowlands, from the Pre-Classic (2000 BC to 250 AD) to Post-Classic periods (1000 to 1521 AD) [1, 2]. In particular, a large number of studies suggest that the decline of the Maya civilization in the Terminal Classic Period was greatly influenced by prolonged severe drought events that probably triggered significant societal disruptions [1, 3, 4, 5]. Going further on these issues, the aim of this work is to detect climate regime shifts in several paleoclimate time series from the Yucatán Peninsula (México) that have been used as rainfall proxies [3, 5, 6, 7]. In order to extract information from the paleoclimate data studied, we have used a change point method [8] as implemented in the R package strucchange, as well as the RAMFIT method [9]. The preliminary results show for all the records analysed a prominent regime shift between 400 to 200 BCE (from a noticeable increase to a remarkable fall in precipitation), which is strongest in the recently obtained stalagmite (Itzamna) delta18-O precipitation record [7]. References [1] Gunn, J. D., Matheny, R. T., Folan, W. J., 2002. Climate-change studies in the Maya area. Ancient Mesoamerica, 13(01), 79-84. [2] Yaeger, J., Hodell, D. A., 2008. The collapse of Maya civilization: assessing the interaction of culture, climate, and environment. El Niño, Catastrophism, and Culture Change in Ancient America, 197-251. [3] Hodell, D. A., Curtis, J. H., Brenner, M., 1995. Possible role of climate in the collapse of Classic Maya civilization. Nature, 375(6530), 391-394. [4] Aimers, J., Hodell, D., 2011. Societal collapse: Drought and the Maya. Nature 479(7371), 44-45 (2011). [5] Medina-Elizalde, M., Rohling, E. J., 2012. Collapse of Classic Maya civilization related to modest reduction

Nonlinear detection of paleoclimate-variability transitions possibly related to human evolution

NASA Astrophysics Data System (ADS)

Donges, J. F.; Donner, R. V.; Trauth, M. H.; Marwan, N.; Schellnhuber, H. J.; Kurths, J.

2012-04-01

Potential paleoclimatic driving mechanisms acting on human evolution present an open problem of cross-disciplinary scientific interest. The analysis of paleoclimate archives encoding the environmental variability in East Africa during the last 5 Ma (million years) has triggered an ongoing debate about possible candidate processes and evolutionary mechanisms. In this work, we apply a novel nonlinear statistical technique, recurrence network analysis, to three distinct marine records of terrigenous dust flux. Our method enables us to identify three epochs with transitions between qualitatively different types of environmental variability in North and East Africa during the (i) Mid-Pliocene (3.35-3.15 Ma BP (before present)), (ii) Early Pleistocene (2.25-1.6 Ma BP), and (iii) Mid-Pleistocene (1.1-0.7 Ma BP). A deeper examination of these transition periods reveals potential climatic drivers, including (i) large-scale changes in ocean currents due to a spatial shift of the Indonesian throughflow in combination with an intensification of Northern Hemisphere glaciation, (ii) a global reorganization of the atmospheric Walker circulation induced in the tropical Pacific and Indian Ocean, and (iii) shifts in the dominating temporal variability pattern of glacial activity during the Mid-Pleistocene, respectively. A reexamination of the available fossil record demonstrates statistically significant coincidences between the detected transition periods and major steps in hominin evolution. This suggests that the observed shifts between more regular and more erratic environmental variability may have acted as a trigger for rapid change in the development of humankind in Africa.

Near net shape processing: A necessity for advanced materials applications

NASA Technical Reports Server (NTRS)

Kuhn, Howard A.

1993-01-01

High quality discrete parts are the backbones for successful operation of equipment used in transportation, communication, construction, manufacturing, and appliances. Traditional shapemaking for discrete parts is carried out predominantly by machining, or removing unwanted material to produce the desired shape. As the cost and complexity of modern materials escalates, coupled with the expense and environmental hazards associated with handling of scrap, it is increasingly important to develop near net shape processes for these materials. Such processes involve casting of liquid materials, consolidation of powder materials, or deformation processing of simple solid shapes into the desired shape. Frequently, several of these operations may be used in sequence to produce a finished part. The processes for near net shape forming may be applied to any type of material, including metals, polymers, ceramics, and their composites. The ability to produce shapes is the key to implementation of laboratory developments in materials science into real world applications. This seminar presents an overview of near net shapemaking processes, some application examples, current developments, and future research opportunities.

Modern limnology of two lakes in the Tibetan Plateau - evidence from in-situ monitoring

NASA Astrophysics Data System (ADS)

Wang, M.; Li, X.; Lei, L.; He, Y.; Hou, J.

2013-12-01

The mechanisms of climate change in the Tibetan Plateau, known as the Third Pole, receive more and more attention due to its unique geographic location and the influence of multiple climate systems. Among the paleoclimate archives, widespread lakes provide abundant information on past climate changes and have been investigated for decades. Though many high-quality paleolimnological records have been reported in the Tibetan Plateau, little is known about the modern limnological processes in most Tibetan lakes as most lakes are difficult to access and not ready for long-term monitoring. We have installed a series of temperature data logger at different water levels in two Tibetan lakes, Bangong Co and Dagze Co in July 2012 to monitor hourly variability of temperature profile. Bangong Co (33.5°N, 79.8°E, 4245 m asl) is a freshwater lake (salinity ~0.5 g/L) in the westernmost Tibetan Plateau, receiving melt water from mountain glaciers in the basin. Dagze Co (31.9°N, 87.5°E, 4470 m asl) is saline lake (salinity ~15 g/L) in the central Tibetan Plateau, mostly fed by precipitation. In combination with the climate data in the nearby weather stations, we wish to understand the modern limnological processes in the two lakes and their potential effect on the lake biology, sedimentation, and sedimentary biomarkers. Based on the data collected for the first calendar year (Jul 2012 ~ Aug 2013), we anticipate to understand: 1) the influence of climate on the hydrological processes in high elevation lakes; 2) the difference in the metalimnion in meltwater-fed lake (Bangong Co) and precipitation-fed lake (Dagze Co) and their potential effect on the lake biology; 3) the difference in the spring turnover and fall turnover and the effect of meltwater and salinity.

Size Variation under Domestication: Conservatism in the inner ear shape of wolves, dogs and dingoes.

PubMed

Schweizer, Anita V; Lebrun, Renaud; Wilson, Laura A B; Costeur, Loïc; Schmelzle, Thomas; Sánchez-Villagra, Marcelo R

2017-10-17

A broad sample of wolves, dingoes, and domesticated dogs of different kinds and time periods was used to identify changes in size and shape of the organs of balance and hearing related to domestication and to evaluate the potential utility of uncovered patterns as markers of domestication. Using geometric morphometrics coupled with non-invasive imaging and three-dimensional reconstructions, we exposed and compared complex structures that remain largely conserved. There is no statistically significant difference in the levels of shape variation between prehistoric and modern dogs. Shape variance is slightly higher for the different components of the inner ear in modern dogs than in wolves, but these differences are not significant. Wolves express a significantly greater level of variance in the angle between the lateral and the posterior canal than domestic dog breeds. Wolves have smaller levels of size variation than dogs. In terms of the shape of the semicircular canals, dingoes reflect the mean shape in the context of variation in the sample. This mirrors the condition of feral forms in other organs, in which there is an incomplete return to the characteristics of the ancestor. In general, morphological diversity or disparity in the inner ear is generated by scaling.

Nacre tablet thickness records formation temperature in modern and fossil shells

DOE PAGES

Gilbert, Pupa U. P. A.; Bergmann, Kristin D.; Myers, Corinne E.; ...

2016-12-15

Nacre, the iridescent outer lining of pearls and inner lining of many mollusk shells, is made of periodic, parallel, organic sheets alternating with aragonite (CaCO 3) tablet layers. Nacre tablet thickness (TT) generates both nacre's iridescence and its remarkable resistance to fracture. Despite extensive studies on how nacre forms, the mechanisms controlling TT remain unknown, even though they determine the most conspicuous of nacre's characteristics, visible even to the naked eye.Thermodynamics predicts that temperature (T) will affect both physical and chemical components of biomineralized skeletons. The chemical composition of biominerals is well-established to record environmental parameters, and has therefore beenmore » extensively used in paleoclimate studies. The physical structure, however, has been hypothesized but never directly demonstrated to depend on the environment. Here we observe that the physical TT in nacre from modern and fossil shallow-water shells of the bivalves Pinna and Atrina correlates with T as measured by the carbonate clumped isotope thermometer. Based on the observed TT vs. T correlation, we anticipate that TT will be used as a paleothermometer, useful to estimate paleotemperature in shallow-water paleoenvironments. Here we successfully test the proposed new nacre TT thermometer on two Jurassic Pinna shells. The increase of TT with T is consistent with greater aragonite growth rate at higher T, and with greater metabolic rate at higher T. Thus, it reveals a complex, T-dependent biophysical mechanism for nacre formation.« less

Nacre tablet thickness records formation temperature in modern and fossil shells

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

Gilbert, Pupa U. P. A.; Bergmann, Kristin D.; Myers, Corinne E.

Nacre, the iridescent outer lining of pearls and inner lining of many mollusk shells, is made of periodic, parallel, organic sheets alternating with aragonite (CaCO 3) tablet layers. Nacre tablet thickness (TT) generates both nacre's iridescence and its remarkable resistance to fracture. Despite extensive studies on how nacre forms, the mechanisms controlling TT remain unknown, even though they determine the most conspicuous of nacre's characteristics, visible even to the naked eye.Thermodynamics predicts that temperature (T) will affect both physical and chemical components of biomineralized skeletons. The chemical composition of biominerals is well-established to record environmental parameters, and has therefore beenmore » extensively used in paleoclimate studies. The physical structure, however, has been hypothesized but never directly demonstrated to depend on the environment. Here we observe that the physical TT in nacre from modern and fossil shallow-water shells of the bivalves Pinna and Atrina correlates with T as measured by the carbonate clumped isotope thermometer. Based on the observed TT vs. T correlation, we anticipate that TT will be used as a paleothermometer, useful to estimate paleotemperature in shallow-water paleoenvironments. Here we successfully test the proposed new nacre TT thermometer on two Jurassic Pinna shells. The increase of TT with T is consistent with greater aragonite growth rate at higher T, and with greater metabolic rate at higher T. Thus, it reveals a complex, T-dependent biophysical mechanism for nacre formation.« less

Postglacial Records of Southern Hemisphere Climate and Oceanographic Change From the New Zealand Subantarctic Auckland Islands

NASA Astrophysics Data System (ADS)

Moy, C. M.; Gilmer, G.; Nichols, J. E.; Browne, I. M.; Curtin, L.; Vandergoes, M.; Aebig, C.; Wilson, G. S.

2017-12-01

The strength and latitudinal position of the Southern Hemisphere westerly winds (SHWW) play a fundamental role in influencing mid-latitude climate and CO2 exchange between the Southern Ocean and the atmosphere along seasonal to glaicial-interglacial timescales. Despite their importance, our understanding of past SHWW change is limited by the small number of paleoclimate records from the modern wind maximum, which are often not in agreement. The New Zealand subantarctic Auckland Islands are located within the core of the modern wind belt (50°S), a key latitude where ocean-atmospheric linkages between the Antarctic and mid-latitudes are strong. In contrast to other subantarctic islands on the Campbell Plateau, the Auckland Islands have multiple protected fjord sub-basins, deep lakes, and peatlands that are advantageous for the development of high-resolution paleoclimate records. We will present ongoing work towards the establishment of multi-proxy and multi-site reconstructions of past SHWW variability from the Auckland Islands. Modern process and paleoclimate studies suggest that in lacustrine and fjord settings, the degree of water column mixing, the stable isotopic composition of n-alkanes and benthic foraminifera, and the influx of terrestrial organic matter are good indicators of wind-induced mixing of the water column or precipitation-driven erosion within catchments. During the Late Glacial and early Holocene (15 to 9 ka), elevated long-chain n-alkane δD values from ombrotrophic peatlands and an increase in the concentration of redox-sensitive elements in fjord sediment cores, signal weakening of the SHWW that appears to be coincident with periods of rapid deglacial warming of West Antarctica. Since 5.5 ka, we interpret declining n-alkane δD values to indicate enhanced westerly flow. These interpretations are in broad agreement with terrestrial paleoclimate records developed from southern South America and argue for a symmetrical response of the SHWW during

Body temperatures of modern and extinct vertebrates from 13C-18O bond abundances in bioapatite

PubMed Central

Eagle, Robert A.; Schauble, Edwin A.; Tripati, Aradhna K.; Tütken, Thomas; Hulbert, Richard C.; Eiler, John M.

2010-01-01

The stable isotope compositions of biologically precipitated apatite in bone, teeth, and scales are widely used to obtain information on the diet, behavior, and physiology of extinct organisms and to reconstruct past climate. Here we report the application of a new type of geochemical measurement to bioapatite, a “clumped-isotope” paleothermometer, based on the thermodynamically driven preference for 13C and 18O to bond with each other within carbonate ions in the bioapatite crystal lattice. This effect is dependent on temperature but, unlike conventional stable isotope paleothermometers, is independent from the isotopic composition of water from which the mineral formed. We show that the abundance of 13C-18O bonds in the carbonate component of tooth bioapatite from modern specimens decreases with increasing body temperature of the animal, following a relationship between isotope “clumping” and temperature that is statistically indistinguishable from inorganic calcite. This result is in agreement with a theoretical model of isotopic ordering in carbonate ion groups in apatite and calcite. This thermometer constrains body temperatures of bioapatite-producing organisms with an accuracy of 1–2 °C. Analyses of fossilized tooth enamel of both Pleistocene and Miocene age yielded temperatures within error of those derived from similar modern taxa. Clumped-isotope analysis of bioapatite represents a new approach in the study of the thermophysiology of extinct species, allowing the first direct measurement of their body temperatures. It will also open new avenues in the study of paleoclimate, as the measurement of clumped isotopes in phosphorites and fossils has the potential to reconstruct environmental temperatures. PMID:20498092

Paleoclimate of the Earth and solar activity

NASA Astrophysics Data System (ADS)

Dergachev, V. A.

2017-09-01

The paper focuses on climate variations caused by the orbital effect and solar activity over the last one million years and oscillations (warming or cooling) of the climate since the last ice age retreat. Attention is paid to a significant discrepancy in the trend of global temperature change during the modern interglacial epoch (Holocene) obtained by various methods. A long-term cooling trend was observed in the summer temperature of the Northern Hemisphere during the last 2000 years.

Plant taphonomy in incised valleys: Implications for interpreting paleoclimate from fossil plants

USGS Publications Warehouse

Demko, T.M.; Dubiel, R.F.; Parrish, Judith T.

1998-01-01

Paleoclimatic interpretations of the Upper Triassic Chinle Formation (Colorado Plateau) based on plants conflict with those based on the sedimentary rocks. The plants are suggestive of a humid, equable climate, whereas the rocks are more consistent with deposition under highly seasonal precipitation and ground-water conditions. Fossil plant assemblages are limited to the lower members of the Chinle Formation, which were deposited within incised valleys that were cut into underlying Lower to Middle Triassic and older rocks. In contrast, the upper members of the formation, which were deposited across the fluvial plain after the incised valleys were filled, have few preserved fossil plants. The taphonomic characteristics of the plant fossil assemblages, within the stratigraphic and hydrologic context of the incised valley-fill sequence, explain the vertical and lateral distribution of these assemblages. The depositional, hydrological, and near-surface geochemical conditions were more conducive to preservation of the plants. Fossil plant assemblages in fully terrestrial incised-valley fills should be taphonomically biased toward riparian wetland environments. If those assemblages are used to interpret paleoclimate, the paleoclimatic interpretations will also be biased. The bias may be particularly strong in climates such as those during deposition of the Chinle Formation, when the riparian wetlands may reflect local hydrologic conditions rather than regional climate, and should be taken into account when using these types of plant assemblages in paleoclimatic interpretations.

Postglacial paleoclimates of the Foxe Basin and surrounding regions (Nunavut, Canada): a multiproxy lake sediment archive study

NASA Astrophysics Data System (ADS)

Pienitz, Reinhard; Beaudoin, Anne; Narancic, Biljana; Rolland, Nicolas; Wagner, Anne-Marie; Zimmermann, Claudia

2013-04-01

Climate change reports show that global warming effects, which are amplified at high latitudes, drive unprecedented environmental changes (ACIA 2005; AMAP-SWIPA 2011). However, not all arctic regions yield the same rate of change (Smol et al. 2005). Several paleoclimate studies completed in areas surrounding the southern Foxe Basin, in Nunavik and Labrador suggest that these regions experienced relatively subtle climatic and environmental changes over the recent past (Pienitz et al. 2004) as compared to the drastic changes reported from the Canadian High Arctic. These contrasting scenarios underscore the need to increase our knowledge of past and present environmental conditions across the Arctic in order to refine our capacity to model past, present and future environmental impacts. Unfortunately, instrumental data available for developing regional and global climate models do not adequately capture the natural environmental variability that has affected these regions over the past. In an effort to explore the potential responses of northern freshwater ecosystems and their watersheds to climatic change and to place instrumental records into a longer-term perspective, we use a multi-proxy paleolimnological approach to study the sedimentary records preserved in several lakes distributed across regions bordering the Foxe Basin (65°-70°N; 71°-85°W) in Nunavut. This presentation will showcase the preliminary results obtained through studies of lake sediment records from the Foxe Peninsula, Southampton Island, Melville Peninsula, Steensby Inlet and the Nettilling Lake area (Nunavut, Canada). Combined with sedimentological analyses (X-ray profiles, XRF, CHN, grain size, magnetic susceptibility), changes in the composition of both fossil chironomid and diatom assemblages provide an improved understanding of the temporal and spatial variability and of the timing of past climatic events since the last deglaciation. Our central objective is to generate a network of

Role of ground water in geomorphology, geology, and paleoclimate of the Southern High Plains, USA.

PubMed

Wood, Warren W

2002-01-01

Study of ground water in the Southern High Plains is central to an understanding of the geomorphology, deposition of economic minerals, and climate change record in the area. Ground water has controlled the course of the Canadian and Pecos rivers that isolated the Southern High Plains from the Great Plains and has contributed significantly to the continuing retreat of the westward escarpment. Evaporative and dissolution processes are responsible for current plateau topography and the development of the signature 20,000 small playa basins and 40 to 50 large saline lake basins in the area. In conjunction with eolian processes, ground water transport controls the mineralogy of commercially valuable mineral deposits and sets up the distribution of fine efflorescent salts that adversely affect water quality. As the water table rises and retreats, lunette and tufa formation provides valuable paleoclimate data for the Southern High Plains. In all these cases, an understanding of ground water processes contributes valuable information to a broad range of geological topics, well beyond traditional interest in water supply and environmental issues.

A record of more than 500,000 years of large-volume travertine formation in the southwestern United States and links between paleohydrology, paleoclimate, and landscape evolution

NASA Astrophysics Data System (ADS)

Priewisch, A.; Crossey, L. J.; Embid, E.; Karlstrom, K. E.; Polyak, V.; Asmerom, Y.; Ricketts, J. W.

2011-12-01

as times of high groundwater flow and hence as a proxy for regional paleohydrology/paleoclimate controls while the locations of the travertine occurrences (along faults of the Jemez lineament and Rio Grande rift) reflect more local CO2-discharge (tectonic) controls. These travertine occurrences are important indicators of the extent of past natural CO2 leakage that can inform carbon sequestration models both in areas of modern CO2 gas fields (Springerville) and at sites of potential paleo-gas fields. The travertine platforms now occupy positions high in the landscape (inverted topography) and also provide data on the scales and timing of regional landscape denudation.

Younger Dryas to Early Holocene paleoclimate in Cantabria (N Spain): Constraints from speleothem Mg, annual fluorescence banding and stable isotope records

NASA Astrophysics Data System (ADS)

Rossi, Carlos; Bajo, Petra; Lozano, Rafael P.; Hellstrom, John

2018-07-01

The Younger Dryas (YD) stadial represents the most abrupt climate change of the Earth's recent history. Thus, understanding its causes and different local responses is relevant for Quaternary paleoclimatology. We present a speleothem high-resolution proxy record of the Lateglacial to Early Holocene paleoclimate of the Cantabrian Cordillera (N Spain), a strategic location to evaluate the influence of North Atlantic events such as the YD on South-Western Europe. Fluorescence lamination, growth-rate, stable-isotope, and [Mg] records from stalagmite SIR-1 were dated using an age-depth model constrained by U-Th dates and annual-lamina counting. The YD is recorded as a prominent positive δ13C excursion whose chronology (12.95 ± 0.14 to 11.62 ± 0.16 ka) and shape closely agree with the GS-1 stadial as defined in Greenland ice, supporting the event synchronicity in both areas. A colder and drier YD climate limited soil productivity and dripwater availability, leading to higher δ13C and [Mg], reduced growth rate, and virtually absent fluorescence lamination. The early YD record (until ∼12.5 ka) reflects increasing aridity, whereas the late YD (from ∼12.2 ka on) shows the opposite trend. At the YD boundaries, temperature changes influenced the [Mg] record by modifying the Mg partition into calcite. However, this effect was superseded by major changes in dripwater Mg/Ca linked to rainfall variations. During the Early Holocene, the Arnero Sierra was forested and had a relatively warm and humid seasonal climate, indicated in SIR-1 by higher growth rates, lower δ13C and [Mg], and well-developed fluorescent lamination. Similar to other high-resolution stalagmitic records of the Cordillera, from ∼8.5 to 8.0 ka SIR-1 reflects a temporary trend of increasing aridity.

Romanian traditional motif - element of modernity in clothing

NASA Astrophysics Data System (ADS)

Doble, L.; Stan, O.; Suteu, M. D.; Albu, A.; Bohm, G.; Tsatsarou-Michalaki, A.; Gialinou, E.

2017-10-01

In this paper are presented the phases for improving from an aesthetic point of view a clothing item, the jacket respectively, with a straight cut for women using software design patterns, computerised graphics and textile different modern technologies including: industrial embroidery, digital printing, sublimation. In the first phase a documentation was prepared in the Ethnographic Museum of Transylvania from Cluj Napoca where more traditional motifs were selected specific to Transylvania etnographic region and were reintepreted and stylized whilst preserving the symbolism and color range specified to the area. For the styling phase was used CorelDraw vector graphics program that allows changing the shape, size and color of the drawings without affecting the identity of the pattern. In the patterns design phase Gemini CAD software was used and for the modeling and model development Optitex software was used. The part for garnishing the model was performed using Embrodery machine software reproducing the stylized motif identically. In order to obtain a significantly improved aesthetic look and an added artistic value the pattern chosen for the jacket was done using a combination of modern textile technologies. This has allowed the realization of a particular texture on the surface of the designed product, demonstrating that traditional patterns can be reintepreted in modern clothing

Development and Application of Otoliths as Paleoclimate Proxies.

NASA Astrophysics Data System (ADS)

Andrus, C. T.; Crowe, D. E.; Sandweiss, D. H.

2001-12-01

Otoliths are small (<20 mm) accretionary aragonite ear structures in teleost fish. Otolith aragonite is precipitated in oxygen isotope equilibrium with ambient water, thus otolith δ 18O values are proxies for temperature. Otolith growth is marked by concentric bands that reflect, in most species, daily to annual growth periods. New techniques of high-resolution CO2 extraction from aragonite, such as laser microprobe and micromill, permit measurement of δ 18O at temporal resolutions fine enough to discern seasonal climate variation. Otoliths are abundant in most maritime archaeological sites and are also found as fossils as old as the Jurassic. Gross otolith morphology is taxon-specific, often permitting identification to the species level. Depending on the behavior and natural history of each species, conditions within different environments and habitats may be recorded in the isotope chemistry. These environments range from abyssal oceanic depths to mid-continental rivers and lakes, but the most abundant archaeological otoliths are from fish that inhabit shallow coastal waters. Unlike most proxies that are sessile, fish are pelagic and thus record a paleoclimate record indicative of the range of habitats in which the individual grew. In fish with well-understood life histories, such as most economically significant species, this permits evaluation of multiple habitat climates through ontogeny as recorded in the incremental growth. In species with a defined home range (i.e. non-migratory), an integrated temperature history of region can be reconstructed from the δ 18O values, thus avoiding micro-environmental biases sometimes associated with sessile proxies. An example of such use of otoliths is our recent analyses of δ 18O profiles from mid-Holocene archaeological sites in coastal Peru that reflect sea surface temperature (SST) histories. This is an area of coast that lacks more traditional proxies, such as coral, yet is central to the understanding of a

Paleopathological findings in radiographs of ancient and modern Greek skulls.

PubMed

Papagrigorakis, Manolis J; Karamesinis, Kostas G; Daliouris, Kostas P; Kousoulis, Antonis A; Synodinos, Philippos N; Hatziantoniou, Michail D

2012-12-01

The skull, when portrayed radiologically, can be a useful tool in detecting signs of systemic diseases and results of pathological growth mechanisms. The aim of this study was therefore to examine, compare, and classify findings in cranial configuration of pathological origin, in modern and ancient skulls. The material consists of 240 modern and 141 ancient dry skulls. Three radiographs for each skull (lateral, anteroposterior, basilar) provide enough evidence for differential diagnoses. Cases of osteoporosis are among the interesting pathological findings. A prevalence of female modern skulls in those determined as osteoporotic skulls is noted. Special interest is placed on the area of the sella turcica and many variations, regarding the shape and texture, are recognized both in ancient and modern skulls. Malignancies and important causes of cranial destruction are identified in both skull collections. Diploid thickening and osteolytic areas appear commonly among ancient remains. Moreover, from the ancient skull collection, one case possibly recognizable as fibrous dysplasia is noted while another case with an unusual exostosis gives rise to many questions. Interpreted with caution, the results of the present study, which can serve as an approach of paleopathology and paleoradiology, indicate similarity trends in cranial configuration of pathologic origin in modern and ancient people. Radiography and cephalometry were the main diagnostic tools used to gather evidence and are evaluated as a quite appropriate method to examine anthropological material and assess the internal structure of skeletal remains since they are non-destructive techniques.

Tropical Pacific climate during the Medieval Climate Anomaly: progress and pitfalls

NASA Astrophysics Data System (ADS)

Cobb, K. M.; Westphal, N.; Charles, C.; Sayani, H. R.; Edwards, R. L.; Cheng, H.; Grothe, P. R.; Chen, T.; Hitt, N. T.; O'Connor, G.; Atwood, A. R.

2016-12-01

A vast trove of paleoclimate records indicates that the Medieval Climate Anomaly (MCA; 900-1200AD) was characterized by relative warmth throughout the Northern Hemisphere and significant hydroclimate anomalies - particularly well-resolved over North America - that posed a challenge to human populations. The global-scale nature of the climate anomalies has driven speculation that the tropical Pacific, with its rich spectrum of natural variability and far-reaching impact, may have undergone a prolonged reorganization during the MCA. While some key records from across the tropical Pacific document significant changes in temperature and/or hydrology, a dynamically-consistent picture of the MCA tropical Pacific climate state has proven elusive. In particular, there are few if any robust paleoclimate constraints from the central Pacific, where even modest changes in ocean temperature translate into distinct patterns of global atmospheric teleconnections. Here, we present a new collection of fossil coral multi-proxy records from Christmas Island (2N, 157W) that provide robust constraints on both temperature and hydrological changes during the MCA. We employ both modern coral data, instrumental climate data, and climate model output in developing a framework for quantifying the uncertainties associated with the new fossil coral data. In doing so, we illustrate the clear benefits of modern environmental monitoring campaigns that inform the generation of paleoclimate pseudo-proxies.

Coupled hydromechanical paleoclimate analyses of density-dependant groundwater flow in discretely fractured crystalline rock settings

NASA Astrophysics Data System (ADS)

Normani, S. D.; Sykes, J. F.; Jensen, M. R.

2009-04-01

A high resolution sub-regional scale (84 km2) density-dependent, fracture zone network groundwater flow model with hydromechanical coupling and pseudo-permafrost, was developed from a larger 5734 km2 regional scale groundwater flow model of a Canadian Shield setting in fractured crystalline rock. The objective of the work is to illustrate aspects of regional and sub-regional groundwater flow that are relevant to the long-term performance of a hypothetical nuclear fuel repository. The discrete fracture dual continuum numerical model FRAC3DVS-OPG was used for all simulations. A discrete fracture zone network model delineated from surface features was superimposed onto an 789887 element flow domain mesh. Orthogonal fracture faces (between adjacent finite element grid blocks) were used to best represent the irregular discrete fracture zone network. The crystalline rock between these structural discontinuities was assigned properties characteristic of those reported for the Canadian Shield at the Underground Research Laboratory at Pinawa, Manitoba. Interconnectivity of permeable fracture features is an important pathway for the possibly relatively rapid migration of average water particles and subsequent reduction in residence times. The multiple 121000 year North American continental scale paleoclimate simulations are provided by W.R. Peltier using the University of Toronto Glacial Systems Model (UofT GSM). Values of ice sheet normal stress, and proglacial lake depth from the UofT GSM are applied to the sub-regional model as surface boundary conditions, using a freshwater head equivalent to the normal stress imposed by the ice sheet at its base. Permafrost depth is applied as a permeability reduction to both three-dimensional grid blocks and fractures that lie within the time varying permafrost zone. Two different paleoclimate simulations are applied to the sub-regional model to investigate the effect on the depth of glacial meltwater migration into the subsurface. In

Geomorphic evidence for former lobate debris aprons at low latitudes on Mars: Indicators of the Martian paleoclimate

USGS Publications Warehouse

Hauber, E.; Van Gasselt, S.; Chapman, M.G.; Neukum, G.

2008-01-01

Circumferential depressions enclosing mesas and plateaus in the northern Kasei Valles and in the Tartarus Colles regions of Mars are interpreted as indicators of the former extent of lobate debris aprons, thought to be mixtures of ice and elastic particles. These former lobate debris aprons existed about 1 Ga ago and were embayed by lavas or other flow deposits. After the lobate debris aprons had been removed by sublimation and deflation, topographic depressions with a depth of 50 m and a width of several kilometers were left behind between the mesa or plateau scarp and the solidified flow materials. These depressions or moats are located equatorward of ??30?? at significantly lower latitudes than generally observed for occurrences of modem, intact lobate debris aprons. This observation provides evidence that the paleoclimate at that time was different than today, probably due to a higher averaged obliquity of the planet's rotational axis. Copyright 2008 by the American Geophysical Union.

Longitudinal bunch shaping of picosecond high-charge MeV electron beams

DOE PAGES

Beaudoin, B. L.; Thangaraj, J. C. T.; Edstrom, Jr., D.; ...

2016-10-20

With ever increasing demands for intensities in modern accelerators, the understanding of space-charge effects becomes crucial. Herein are presented measurements of optically shaped picosecond-long electron beams in a superconducting L-band linac over a wide range of charges, from 0.2 nC to 3.4 nC. At low charges, the shape of the electron beam is preserved, while at higher charge densities, modulations on the beam convert to energy modulations. Here, energy profile measurements using a spectrometer and time profile measurements using a streak camera reveal the dynamics of longitudinal space-charge on MeV-scale electron beams.

Water content, speciation and isotopic composition in volcanic glass: an open window on magma degassing processes or paleoclimate?

NASA Astrophysics Data System (ADS)

Martin, Erwan; Bindeman, Ilya; Balan, Etienne; Palandri, Jim; Seligman, Angela; Villemant, Benoit

2016-04-01

The content, speciation and isotopic composition of water in volcanic glass have been used for decades as recorder of magma degassing or late glass rehydration processes. Magmatic or paleoclimate information are derived depending on the primary (magmatic) or meteoric (secondary) origin of water. In this study, we attempt to discriminate residual magmatic from secondary meteoric water in volcanic glass. Using samples from different geological settings and different climatic conditions, we show that the H-isotope composition and water content measured via a TC/EA-MAT253 system in volcanic glass alone are not always sufficient to provide clear distinction between magmatic and meteoric origin. However, it is quite easy to resolve δD evolution during post-deposit rehydration by meteoric water from magma degassing when volcanic glass have a δD <-100‰ or >-50‰ and [H2O]tot >1.5-2wt.%. Water speciation inferred from near-infrared spectroscopy also provides valuable information complementary to isotopic and total water measurements. During magma degassing (typically with [H2O]tot decreasing from 6wt.% to ~0wt.% water) H2O/OH is expected to decrease from 2 to close to 0. However, our dataset shows the opposite trend with an increase of H2O/OH from 2 to ~5. We interpret it as post deposit rehydration of the volcanic glass. Overall our results show that the discrimination of the water origin is essential to discuss magma degassing processes or paleoclimatic reconstitutions. The present study of hydrous glass supports the use of H-isotopes of volcanic glass to discuss paleoclimate reconstitution in a specific region. To this purpose, the volcanic glass has to be almost fully rehydrated in order to fingerprint the isotopic composition of the rehydration water. A sharp time constrain can be obtained if the full rehydration occurs quickly after the eruption. This is most likely to occur in meters thick volcanic pyroclast deposits that undergo slow cooling rates and thus can

Entangled γ-photons—classical laboratory exercise with modern detectors

NASA Astrophysics Data System (ADS)

Hetfleiš, Jakub; Lněnička, Jindřich; Šlégr, Jan

2018-03-01

This paper describes the application of modern semiconductor detectors of γ and β radiation, which can be used in undergraduate laboratory experiments and lecture demonstrations as a replacement for Geiger-Müller (GM) tubes. Unlike GM tubes, semiconductor detectors do not require a high voltage power source or shaping circuits. The principle of operation of semiconductor detectors is discussed briefly, and classical experiments from nuclear physics are described, ranging from the measurements of linear and mass attenuation coefficient to a demonstration of entangled γ-photons.

Remote interferometry by digital holography for shape control

NASA Astrophysics Data System (ADS)

Baumbach, Torsten; Osten, Wolfgang; Falldorf, Claas; Jueptner, Werner P. O.

2002-06-01

Modern production requires more and more effective methods for the inspection and quality control at the production place. Outsourcing and globalization result in possible large distances between co-operating partners. This may cause serious problems with respect to the just-in-time exchange of information and the response to possible violations of quality standards. Consequently new challenges arise for optical measurement techniques especially in the field of industrial shape control. A possible solution for these problems can be delivered by a technique that stores optically the full 3D information of the objects to be compared and where the data can be transported over large distances. In this paper we describe the progress in implementing a new technique for the direct comparison of the shape and deformation of two objects with different microstructure where it is not necessary that both samples are located at the same place. This is done by creating a coherent mask for the illumination of the sample object. The coherent mask is created by Digital Holography to enable the instant access to the complete optical information of the master object at any wanted place. The transmission of the digital master holograms to this place can be done via digital telecommunication networks. The comparison can be done in a digital or analogue way. Both methods result in a disappearance of the object shape and the appearance of the shape or deformation difference between the two objects only. The analogue reconstruction of the holograms with a liquid crystal spatial light modulator can be done by using the light modulator as an intensity modulator or as an phase modulator. The reconstruction technique and the space bandwidth of the light modulator will influence the quality of the result. Therefore the paper describes the progress in applying modern spatial light modulators and digital cameras for the effective storage and optical reconstruction of coherent masks.

Permian paleoclimate data from fluid inclusions in halite

USGS Publications Warehouse

Benison, K.C.; Goldstein, R.H.

1999-01-01

This study has yielded surface water paleotemperatures from primary fluid inclusions in mid Permian Nippewalla Group halite from western Kansas. A 'cooling nucleation' method is used to generate vapor bubbles in originally all-liquid primary inclusions. Then, surface water paleotemperatures are obtained by measuring temperatures of homogenization to liquid. Homogenization temperatures ranged from 21??C to 50??C and are consistent along individual fluid inclusion assemblages, indicating that the fluid inclusions have not been altered by thermal reequilibration. Homogenization temperatures show a range of up to 26??C from base to top of individual cloudy chevron growth bands. Petrographic and fluid inclusion evidence indicate that no significant pressure correction is needed for the homogenization temperature data. We interpret these homogenization temperatures to represent shallow surface water paleotemperatures. The range in temperatures from base to top of single chevron bands may reflect daily temperatures variations. These Permian surface water temperatures fall within the same range as some modern evaporative surface waters, suggesting that this Permian environment may have been relatively similar to its modern counterparts. Shallow surface water temperatures in evaporative settings correspond closely to local air temperatures. Therefore, the Permian surface water temperatures determined in this study may be considered proxies for local Permian air temperatures.

The Mitonuclear Dimension of Neanderthal and Denisovan Ancestry in Modern Human Genomes

PubMed Central

Sharbrough, Joel; Havird, Justin C.; Noe, Gregory R.; Warren, Jessica M.

2017-01-01

Abstract Some human populations interbred with Neanderthals and Denisovans, resulting in substantial contributions to modern-human genomes. Therefore, it is now possible to use genomic data to investigate mechanisms that shaped historical gene flow between humans and our closest hominin relatives. More generally, in eukaryotes, mitonuclear interactions have been argued to play a disproportionate role in generating reproductive isolation. There is no evidence of mtDNA introgression into modern human populations, which means that all introgressed nuclear alleles from archaic hominins must function on a modern-human mitochondrial background. Therefore, mitonuclear interactions are also potentially relevant to hominin evolution. We performed a detailed accounting of mtDNA divergence among hominin lineages and used population-genomic data to test the hypothesis that mitonuclear incompatibilities have preferentially restricted the introgression of nuclear genes with mitochondrial functions. We found a small but significant underrepresentation of introgressed Neanderthal alleles at such nuclear loci. Structural analyses of mitochondrial enzyme complexes revealed that these effects are unlikely to be mediated by physically interacting sites in mitochondrial and nuclear gene products. We did not detect any underrepresentation of introgressed Denisovan alleles at mitochondrial-targeted loci, but this may reflect reduced power because locus-specific estimates of Denisovan introgression are more conservative. Overall, we conclude that genes involved in mitochondrial function may have been subject to distinct selection pressures during the history of introgression from archaic hominins but that mitonuclear incompatibilities have had, at most, a small role in shaping genome-wide introgression patterns, perhaps because of limited functional divergence in mtDNA and interacting nuclear genes. PMID:28854627

Paleoclimate Reconstruction of Guangxi in SW China during the Past 2000-Year: Stalagmite Records from Two Caves

NASA Astrophysics Data System (ADS)

Lien, W. Y.; Li, H. C.; Mii, H. S.

2017-12-01

Paleoclimate reconstructions help us to understand the role of the East Asian Summer Monsoon (EASM) on local precipitation and controlling factor of EASM variability, and to improve our climatic prediction. This study presents two stalagmite records from Jinlun Cave (23.553oN, 108.265oE) and Yilingyan Cave (23.041oN, 108.297oE) which are only 60 km apart in Guangxi Province, China. The 35-cm long stalagmite JL12 from Jinlun Cave and 10-cm long stalagmite YLY12 from Yilingyan Cave reveal 1500-year and 2000-year continuous growth respectively based on AMS 14C dating. Data points of the AMS 14C dates with the least dead carbon fraction (DCF) are used to build up the age model. Although dead carbons influence the 14C dating results, it is a feasible dating method for the stalagmites as 230Th/U dating on both stalagmites was not successful due to low U contents. A total of 1586 samples from JL12 and 948 samples from YLY12 have been done for stable isotopes analyses to serve as paleoclimate proxies. Comparison of the d18O records with the local rainfall records and the dry-wetness historic records shows the stalagmite d18O records as a rainfall proxy. The JL12 d18O record resembles the YLY12 d18O record in general, though some differences exist, which confirms the d18O records representing the local climate. The relatively lighter (lower) d18O values of the JL12 and YLY12 records during the Medieval Warm Period (MWP, AD900-1200) indicate stronger EASM. In the first phase of Little Ice Age (LIA), from AD1300 to AD1560, the d18O fluctuate drastically and the average during this period was lower, while the d18O was higher in the second phase of Little Ice Age (AD1560-AD1760), exhibiting a drier and stable climate in the second phase. Furthermore, the DCF varies through the stalagmite records, ascending during the LIA, descending during the MWP, which informs dry condition during the LIA and a moist climate in the MWP. Spectral analysis of the high-resolution d18O records

Shape of the orbital opening: individual characterization and analysis of variability in modern humans, Gorilla gorilla, and Pan troglodytes.

PubMed

Schmittbuhl, M; Le Minor, J M; Allenbach, B; Schaaf, A

1999-05-01

The description of the human orbital shape is principally qualitative in the classical literature, and characterised by adjectives such as circular, rectangular or quadrangular. In order to provide a precise quantification and interpretation of this shape, a study based on automatic image analysis and Fourier analysis was carried out on 45 human skulls (30 males, 15 females), and for comparison on 61 skulls of Gorilla gorilla (40 males, 21 females), and 34 skulls of Pan troglodytes (20 males, 14 females). Sexual dimorphism in the shape of the orbital opening was not demonstrated. Its dominant morphological features could be characterized by Fourier analysis; elliptical elongation and quadrangularity were dominant morphological features of the shape of the orbital opening in the three species. Elliptical elongation was more marked in humans and Pan, whereas quadrangularity was particularly emphasized in Gorilla. An intraspecific variability of the shape of the orbital opening existed in humans, Gorilla and Pan, and seemed close in the three species. Interspecific partition between humans, Gorilla and Pan was demonstrated despite the variability observed in the three species studied. Interspecific differences between Gorilla and the Pan-humans group were principally explained by the differences in quadrangularity, and by differences in orientation of triangularity and pentagonality. Differences in the shape of the orbital opening between humans and Pan were principally explained by differences in hexagonality, and by differences in orientation of quadrangularity. A closeness of shape between some humans and some individuals in Pan and, to a lesser degree, with some individuals in Gorilla was observed, demonstrating the existence of a morphological continuum of the shape of the orbital opening in hominoids.

Shape-controlled synthesis of metal nanocrystals: simple chemistry meets complex physics?

PubMed

Xia, Younan; Xiong, Yujie; Lim, Byungkwon; Skrabalak, Sara E

2009-01-01

Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. Our aim is to present a comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution-phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Finally, we highlight a number of applications that have been enabled and/or enhanced by the shape-controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take.

Spatio-temporal shaping of photocathode laser pulses for linear electron accelerators

NASA Astrophysics Data System (ADS)

Mironov, S. Yu; Andrianov, A. V.; Gacheva, E. I.; Zelenogorskii, V. V.; Potemkin, A. K.; Khazanov, E. A.; Boonpornprasert, P.; Gross, M.; Good, J.; Isaev, I.; Kalantaryan, D.; Kozak, T.; Krasilnikov, M.; Qian, H.; Li, X.; Lishilin, O.; Melkumyan, D.; Oppelt, A.; Renier, Y.; Rublack, T.; Felber, M.; Huck, H.; Chen, Y.; Stephan, F.

2017-10-01

Methods for the spatio-temporal shaping of photocathode laser pulses for generating high brightness electron beams in modern linear accelerators are discussed. The possibility of forming triangular laser pulses and quasi-ellipsoidal structures is analyzed. The proposed setup for generating shaped laser pulses was realised at the Institute of Applied Physics (IAP) of the Russian Academy of Sciences (RAS). Currently, a prototype of the pulse-shaping laser system is installed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). Preliminary experiments on electron beam generation using ultraviolet laser pulses from this system were carried out at PITZ, in which electron bunches with a 0.5-nC charge and a transverse normalized emittance of 1.1 mm mrad were obtained. A new scheme for the three-dimensional shaping of laser beams using a volume Bragg profiled grating is proposed at IAP RAS and is currently being tested for further electron beam generation experiments at the PITZ photoinjector.

The second modern condition? Compressed modernity as internalized reflexive cosmopolitization.

PubMed

Kyung-Sup, Chang

2010-09-01

Compressed modernity is a civilizational condition in which economic, political, social and/or cultural changes occur in an extremely condensed manner in respect to both time and space, and in which the dynamic coexistence of mutually disparate historical and social elements leads to the construction and reconstruction of a highly complex and fluid social system. During what Beck considers the second modern stage of humanity, every society reflexively internalizes cosmopolitanized risks. Societies (or their civilizational conditions) are thereby being internalized into each other, making compressed modernity a universal feature of contemporary societies. This paper theoretically discusses compressed modernity as nationally ramified from reflexive cosmopolitization, and, then, comparatively illustrates varying instances of compressed modernity in advanced capitalist societies, un(der)developed capitalist societies, and system transition societies. In lieu of a conclusion, I point out the declining status of national societies as the dominant unit of (compressed) modernity and the interactive acceleration of compressed modernity among different levels of human life ranging from individuals to the global community. © London School of Economics and Political Science 2010.

Stability of upper face sexual dimorphism in central European populations (Czech Republic) during the modern age.

PubMed

Bejdová, Šárka; Dupej, Ján; Krajíček, Václav; Velemínská, Jana; Velemínský, Petr

2018-01-01

One of the most fundamental issues in forensic anthropology is the determination of sex and population affinity based on various skeletal elements. Therefore, we compared the sexual dimorphism of the upper facial skeleton from a recent Czech population (twenty-first century) with that of a population from Early Modern Age Bohemia (sixteenth to eighteenth centuries). Methods of geometric morphometrics were applied. According to the results, sexual dimorphism in terms of size, shape, and form was statistically significant in both populations. The best results of sex estimation originated from analyses of form. Thus, both size and shape differences should be taken into account for determination of the sex. The accuracy of prediction achieved 91.1% for individuals in the recent population and 87.5% for individuals from the early modern population. Only minor differences were found between sexual dimorphism in the studied populations. We conclude that sexual dimorphism of the upper facial skeleton is stable during the relatively short time period.

Estimates of late middle Eocene pCO2 based on stomatal density of modern and fossil Nageia leaves

NASA Astrophysics Data System (ADS)

Liu, X. Y.; Gao, Q.; Han, M.; Jin, J. H.

2016-02-01

Atmospheric pCO2 concentrations have been estimated for intervals of the Eocene using various models and proxy information. Here we reconstruct late middle Eocene (42.0-38.5 Ma) pCO2 based on the fossil leaves of Nageia maomingensis Jin et Liu collected from the Maoming Basin, Guangdong Province, China. We first determine relationships between atmospheric pCO2 concentrations, stomatal density (SD) and stomatal index (SI) using "modern" leaves of N. motleyi (Parl.) De Laub, the nearest living species to the Eocene fossils. This work indicates that the SD inversely responds to pCO2, while SI has almost no relationship with pCO2. Eocene pCO2 concentrations can be reconstructed based on a regression approach and the stomatal ratio method by using the SD. The first approach gives a pCO2 of 351.9 ± 6.6 ppmv, whereas the one based on stomatal ratio gives a pCO2 of 537.5 ± 56.5 ppmv. Here, we explored the potential of N. maomingensis in pCO2 reconstruction and obtained different results according to different methods, providing a new insight for the reconstruction of paleoclimate and paleoenvironment in conifers.

A statistical shape modelling framework to extract 3D shape biomarkers from medical imaging data: assessing arch morphology of repaired coarctation of the aorta.

PubMed

Bruse, Jan L; McLeod, Kristin; Biglino, Giovanni; Ntsinjana, Hopewell N; Capelli, Claudio; Hsia, Tain-Yen; Sermesant, Maxime; Pennec, Xavier; Taylor, Andrew M; Schievano, Silvia

2016-05-31

Medical image analysis in clinical practice is commonly carried out on 2D image data, without fully exploiting the detailed 3D anatomical information that is provided by modern non-invasive medical imaging techniques. In this paper, a statistical shape analysis method is presented, which enables the extraction of 3D anatomical shape features from cardiovascular magnetic resonance (CMR) image data, with no need for manual landmarking. The method was applied to repaired aortic coarctation arches that present complex shapes, with the aim of capturing shape features as biomarkers of potential functional relevance. The method is presented from the user-perspective and is evaluated by comparing results with traditional morphometric measurements. Steps required to set up the statistical shape modelling analyses, from pre-processing of the CMR images to parameter setting and strategies to account for size differences and outliers, are described in detail. The anatomical mean shape of 20 aortic arches post-aortic coarctation repair (CoA) was computed based on surface models reconstructed from CMR data. By analysing transformations that deform the mean shape towards each of the individual patient's anatomy, shape patterns related to differences in body surface area (BSA) and ejection fraction (EF) were extracted. The resulting shape vectors, describing shape features in 3D, were compared with traditionally measured 2D and 3D morphometric parameters. The computed 3D mean shape was close to population mean values of geometric shape descriptors and visually integrated characteristic shape features associated with our population of CoA shapes. After removing size effects due to differences in body surface area (BSA) between patients, distinct 3D shape features of the aortic arch correlated significantly with EF (r = 0.521, p = .022) and were well in agreement with trends as shown by traditional shape descriptors. The suggested method has the potential to discover

Spring temperature responses of oaks are synchronous with North Atlantic conditions during the last deglaciation

Treesearch

Steven L. Voelker; Paul-Emile Noirot-Cosson; Michael C. Stambaugh; Erin R. McMurry; Frederick C. Meinzer; Barbara Lachenburch; Richard P. Guyette

2012-01-01

Paleoclimate proxies based on the measurement of xylem cell anatomy have rarely been developed across the temperature range of a species or applied to wood predating the most recent millennium. Here we describe wood anatomy-based proxies for spring temperatures in central North America from modern bur oaks (Quercus macrocarpa Michx.). The strong...

Arbitrarily shaped high-coherence electron bunches from cold atoms

NASA Astrophysics Data System (ADS)

McCulloch, A. J.; Sheludko, D. V.; Saliba, S. D.; Bell, S. C.; Junker, M.; Nugent, K. A.; Scholten, R. E.

2011-10-01

Ultrafast electron diffractive imaging of nanoscale objects such as biological molecules and defects in solid-state devices provides crucial information on structure and dynamic processes: for example, determination of the form and function of membrane proteins, vital for many key goals in modern biological science, including rational drug design. High brightness and high coherence are required to achieve the necessary spatial and temporal resolution, but have been limited by the thermal nature of conventional electron sources and by divergence due to repulsive interactions between the electrons, known as the Coulomb explosion. It has been shown that, if the electrons are shaped into ellipsoidal bunches with uniform density, the Coulomb explosion can be reversed using conventional optics, to deliver the maximum possible brightness at the target. Here we demonstrate arbitrary and real-time control of the shape of cold electron bunches extracted from laser-cooled atoms. The ability to dynamically shape the electron source itself and to observe this shape in the propagated electron bunch provides a remarkable experimental demonstration of the intrinsically high spatial coherence of a cold-atom electron source, and the potential for alleviation of electron-source brightness limitations due to Coulomb explosion.

A fresh look at the Last Glacial Maximum using Paleoclimate Data Assimilation

NASA Astrophysics Data System (ADS)

Malevich, S. B.; Tierney, J. E.; Hakim, G. J.; Tardif, R.

2017-12-01

Quantifying climate conditions during the Last Glacial Maximum ( 21ka) can help us to understand climate responses to forcing and climate states that are poorly represented in the instrumental record. Paleoclimate proxies may be used to estimate these climate conditions, but proxies are sparsely distributed and possess uncertainties from environmental and biogeochemical processes. Alternatively, climate model simulations provide a full-field view, but may predict unrealistic climate states or states not faithful to proxy records. Here, we use data assimilation - combining climate proxy records with a theoretical understanding from climate models - to produce field reconstructions of the LGM that leverage the information from both data and models. To date, data assimilation has mainly been used to produce reconstructions of climate fields through the last millennium. We expand this approach in order to produce a climate fields for the Last Glacial Maximum using an ensemble Kalman filter assimilation. Ensemble samples were formed from output from multiple models including CCSM3, CESM2.1, and HadCM3. These model simulations are combined with marine sediment proxies for upper ocean temperature (TEX86, UK'37, Mg/Ca and δ18O of foraminifera), utilizing forward models based on a newly developed suite of Bayesian proxy system models. We also incorporate age model and radiocarbon reservoir uncertainty into our reconstructions using Bayesian age modeling software. The resulting fields show familiar patterns based on comparison with previous proxy-based reconstructions, but additionally reveal novel patterns of large-scale shifts in ocean-atmosphere dynamics, as the surface temperature data inform upon atmospheric circulation and precipitation patterns.

Genetic and archaeological perspectives on the initial modern human colonization of southern Asia.

PubMed

Mellars, Paul; Gori, Kevin C; Carr, Martin; Soares, Pedro A; Richards, Martin B

2013-06-25

It has been argued recently that the initial dispersal of anatomically modern humans from Africa to southern Asia occurred before the volcanic "supereruption" of the Mount Toba volcano (Sumatra) at ∼74,000 y before present (B.P.)-possibly as early as 120,000 y B.P. We show here that this "pre-Toba" dispersal model is in serious conflict with both the most recent genetic evidence from both Africa and Asia and the archaeological evidence from South Asian sites. We present an alternative model based on a combination of genetic analyses and recent archaeological evidence from South Asia and Africa. These data support a coastally oriented dispersal of modern humans from eastern Africa to southern Asia ∼60-50 thousand years ago (ka). This was associated with distinctively African microlithic and "backed-segment" technologies analogous to the African "Howiesons Poort" and related technologies, together with a range of distinctively "modern" cultural and symbolic features (highly shaped bone tools, personal ornaments, abstract artistic motifs, microblade technology, etc.), similar to those that accompanied the replacement of "archaic" Neanderthal by anatomically modern human populations in other regions of western Eurasia at a broadly similar date.

Diode laser spectroscopy: precise spectral line shape measurements

NASA Astrophysics Data System (ADS)

Nadezhdinskii, A. I.

1996-07-01

When one speaks about modern trends in tunable diode laser spectroscopy (TDLS) one should mention that precise line shape measurements have become one of the most promising applications of diode lasers in high resolution molecular spectroscopy. Accuracy limitations of TDL spectrometers are considered in this paper, proving the ability to measure spectral line profile with precision better than 1%. A four parameter Voigt profile is used to fit the experimental spectrum, and the possibility of line shift measurements with an accuracy of 2 × 10 -5 cm -1 is shown. Test experiments demonstrate the error line intensity ratios to be less than 0.3% for the proposed approach. Differences between "soft" and "hard" models of line shape have been observed experimentally for the first time. Some observed resonance effects are considered with respect to collision adiabacity.

Modern CACSD using the Robust-Control Toolbox

NASA Technical Reports Server (NTRS)

Chiang, Richard Y.; Safonov, Michael G.

1989-01-01

The Robust-Control Toolbox is a collection of 40 M-files which extend the capability of PC/PRO-MATLAB to do modern multivariable robust control system design. Included are robust analysis tools like singular values and structured singular values, robust synthesis tools like continuous/discrete H(exp 2)/H infinity synthesis and Linear Quadratic Gaussian Loop Transfer Recovery methods and a variety of robust model reduction tools such as Hankel approximation, balanced truncation and balanced stochastic truncation, etc. The capabilities of the toolbox are described and illustated with examples to show how easily they can be used in practice. Examples include structured singular value analysis, H infinity loop-shaping and large space structure model reduction.

Shape and mechanics in thalattosuchian (Crocodylomorpha) skulls: implications for feeding behaviour and niche partitioning

PubMed Central

Pierce, S E; Angielczyk, K D; Rayfield, E J

2009-01-01

Variation in modern crocodilian and extinct thalattosuchian crocodylomorph skull morphology is only weakly correlated with phylogeny, implying that factors other than evolutionary proximity play important roles in determining crocodile skull shape. To further explore factors potentially influencing morphological differentiation within the Thalattosuchia, we examine teleosaurid and metriorhynchid skull shape variation within a mechanical and dietary context using a combination of finite element modelling and multivariate statistics. Patterns of stress distribution through the skull were found to be very similar in teleosaurid and metriorhynchid species, with stress peaking at the posterior constriction of the snout and around the enlarged supratemporal fenestrae. However, the magnitudes of stresses differ, with metriorhynchids having generally stronger skulls. As with modern crocodilians, a strong linear relationship between skull length and skull strength exists, with short-snouted morphotypes experiencing less stress through the skull than long-snouted morphotypes under equivalent loads. Selection on snout shape related to dietary preference was found to work in orthogonal directions in the two families: diet is associated with snout length in teleosaurids and with snout width in metriorhynchids, suggesting that teleosaurid skulls were adapted for speed of attack and metriorhynchid skulls for force production. Evidence also indicates that morphological and functional differentiation of the skull occurred as a result of dietary preference, allowing closely related sympatric species to exploit a limited environment. Comparisons of the mechanical performance of the thalattosuchian skull with extant crocodilians show that teleosaurids and long-snouted metriorhynchids exhibit stress magnitudes similar to or greater than those of long-snouted modern forms, whereas short-snouted metriorhynchids display stress magnitudes converging on those found in short-snouted modern

Postglacial Records of Southern Hemisphere Westerly Wind Variability From the New Zealand Subantarctic Auckland Islands

NASA Astrophysics Data System (ADS)

Moy, C. M.; Vandergoes, M.; Gilmer, G. J.; Nichols, J. E.; Dagg, B. J.; Wilson, G. S.; Browne, I. M.; Curtin, L. G.; Aebig, C.; McGlone, M.

2015-12-01

The strength and latitudinal position of the Southern Hemisphere westerly winds (SHWW) play a fundamental role in influencing mid latitude climate and carbon dioxide exchange between the Southern Ocean and the atmosphere. Despite their importance, our understanding of past changes in the SHWW is limited by few paleoclimate records from the modern wind maximum that are often not in agreement. The New Zealand subantarctic Auckland Islands are located within the core of the modern wind belt (50°S) where the ocean-atmospheric linkages between the Antarctic and middle latitudes are strong. In contrast to other subantarctic islands on the Campbell Plateau, the Auckland Islands have protected fjord sub-basins, deep lakes, and peatlands that are advantageous for the development of high-resolution paleoclimate records. We will present ongoing work towards the establishment of multi-proxy and multi-site reconstructions of past SHWW variability from the Auckland Islands. Modern process and paleoclimate results from two research cruises in 2014 and 2015 suggest that in lacustrine and fjord settings, the degree of water column mixing, the stable isotopic composition of n-alkanes and benthic foraminifera, the influx of terrestrial organic matter are good indicators of wind-induced mixing of the water column or precipitation-driven erosion within catchments. In ombrotrophic peatlands, hydrogen isotope ratios of specific organic molecules allow reconstructions of the hydrogen isotope ratios of precipitation, which is related to precipitation source area and the latitudinal position of the SHWW. Using macrofossil counts paired with abundances of leaf wax biomarkers, we are able to estimate the moisture balance at peatland coring sites. Early results indicate an overall strengthening of the SHWW at the Auckland Islands through the Holocene. We will discuss these results within the context of complimentary records developed from New Zealand and southern South America to ultimately

On the limits of numerical astronomical solutions used in paleoclimate studies

NASA Astrophysics Data System (ADS)

Zeebe, Richard E.

2017-04-01

Numerical solutions of the equations of the Solar System estimate Earth's orbital parameters in the past and represent the backbone of cyclostratigraphy and astrochronology, now widely applied in geology and paleoclimatology. Given one numerical realization of a Solar System model (i.e., obtained using one code or integrator package), various parameters determine the properties of the solution and usually limit its validity to a certain time period. Such limitations are denoted here as "internal" and include limitations due to (i) the underlying physics/physical model and (ii) numerics. The physics include initial coordinates and velocities of Solar System bodies, treatment of the Moon and asteroids, the Sun's quadrupole moment, and the intrinsic dynamics of the Solar System itself, i.e., its chaotic nature. Numerical issues include solver algorithm, numerical accuracy (e.g., time step), and round-off errors. At present, internal limitations seem to restrict the validity of astronomical solutions to perhaps the past 50 or 60 myr. However, little is currently known about "external" limitations, that is, how do different numerical realizations compare, say, between different investigators using different codes and integrators? Hitherto only two solutions for Earth's eccentricity appear to be used in paleoclimate studies, provided by two different groups that integrated the full Solar System equations over the past >100 myr (Laskar and coworkers and Varadi et al. 2003). In this contribution, I will present results from new Solar System integrations for Earth's eccentricity obtained using the integrator package HNBody (Rauch and Hamilton 2002). I will discuss the various internal limitations listed above within the framework of the present simulations. I will also compare the results to the existing solutions, the details of which are still being sorted out as several simulations are still running at the time of writing.

Methodology of shooting training using modern IT techniques

NASA Astrophysics Data System (ADS)

Gudzbeler, Grzegorz; Struniawski, Jarosław

2017-08-01

Mastering, improvement, shaping and preservation of skills of safe, efficient and effective use of the firearm requires the use of relevant methodology of conducting the shooting training. However reality of police trainings does not usually allow for intensive training shooting with the use of ammunition. An alternative solution is the use of modern training technologies. Example of this is the "Virtual system of improvement tactics of intervention services responsible for security and shooting training." Introduction of stimulator to police trainings will enable complete stuff preparation to achieve its tasks, creating potential of knowledge and experience in many areas, far exceeding the capabilities of conventional training.

Shape-Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?

PubMed Central

Xia, Younan; Xiong, Yujie; Lim, Byungkwon; Skrabalak, Sara E.

2009-01-01

Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. The aim of this article is to present a comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution-phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Toward the end of this article, we highlight a number of applications that have been enabled and/or enhanced by the shape-controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take. PMID:19053095

Tectonics, orbital forcing, global climate change, and human evolution in Africa: introduction to the African paleoclimate special volume.

PubMed

Maslin, Mark A; Christensen, Beth

2007-11-01

The late Cenozoic climate of Africa is a critical component for understanding human evolution. African climate is controlled by major tectonic changes, global climate transitions, and local variations in orbital forcing. We introduce the special African Paleoclimate Issue of the Journal of Human Evolution by providing a background for and synthesis of the latest work relating to the environmental context for human evolution. Records presented in this special issue suggest that the regional tectonics, appearance of C(4) plants in East Africa, and late Cenozoic global cooling combined to produce a long-term drying trend in East Africa. Of particular importance is the uplift associated with the East African Rift Valley formation, which altered wind flow patterns from a more zonal to more meridinal direction. Results in this volume suggest a marked difference in the climate history of southern and eastern Africa, though both are clearly influenced by the major global climate thresholds crossed in the last 3 million years. Papers in this volume present lake, speleothem, and marine paleoclimate records showing that the East African long-term drying trend is punctuated by episodes of short, alternating periods of extreme wetness and aridity. These periods of extreme climate variability are characterized by the precession-forced appearance and disappearance of large, deep lakes in the East African Rift Valley and paralleled by low and high wind-driven dust loads reaching the adjacent ocean basins. Dating of these records show that over the last 3 million years such periods only occur at the times of major global climatic transitions, such as the intensification of Northern Hemisphere Glaciation (2.7-2.5 Ma), intensification of the Walker Circulation (1.9-1.7 Ma), and the Mid-Pleistocene Revolution (1-0.7 Ma). Authors in this volume suggest this onset occurs as high latitude forcing in both Hemispheres compresses the Intertropical Convergence Zone so that East Africa

Evolution of Skull and Mandible Shape in Cats (Carnivora: Felidae)

PubMed Central

Christiansen, Per

2008-01-01

The felid family consists of two major subgroups, the sabretoothed and the feline cats, to which all extant species belong, and are the most anatomically derived of all carnivores for predation on large prey with a precision killing bite. There has been much controversy and uncertainty about why the skulls and mandibles of sabretoothed and feline cats evolved to become so anatomically divergent, but previous models have focused on single characters and no unifying hypothesis of evolutionary shape changes has been formulated. Here I show that the shape of the skull and mandible in derived sabrecats occupy entirely different positions within overall morphospace from feline cats, and that the evolution of skull and mandible shape has followed very different paths in the two subgroups. When normalised for body-size differences, evolution of bite forces differ markedly in the two groups, and are much lower in derived sabrecats, and they show a significant relationship with size and cranial shape, whereas no such relationship is present in feline cats. Evolution of skull and mandible shape in modern cats has been governed by the need for uniform powerful biting irrespective of body size, whereas in sabrecats, shape evolution was governed by selective pressures for efficient predation with hypertrophied upper canines at high gape angles, and bite forces were secondary and became progressively weaker during sabrecat evolution. The current study emphasises combinations of new techniques for morphological shape analysis and biomechanical studies to formulate evolutionary hypotheses for difficult groups. PMID:18665225

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.

The Modern Measurement Technology And Checking Of Shafs Parameters

NASA Astrophysics Data System (ADS)

Tichá, Šárka; Botek, Jan

2015-12-01

This paper is focused on rationalization checking parameters of shaft in companies engaged in the production of components of electric motors, wind turbines and vacuum systems. Customers increasing constantly their requirements to ensure the overall quality of the product, i.e. the quality of machining, dimensional and shape accuracy and overall purity of the subscribed products. The aim of this paper is to introduce using modern measurement technology in controlling these components and compare the results with existing control methodology. The main objective of this rationalization is to eliminate mistakes and shortcomings of current inspection methods.

Effect of panel shape of soccer ball on its flight characteristics

PubMed Central

Hong, Sungchan; Asai, Takeshi

2014-01-01

Soccer balls are typically constructed from 32 pentagonal and hexagonal panels. Recently, however, newer balls named Cafusa, Teamgeist 2, and Jabulani were respectively produced from 32, 14, and 8 panels with shapes and designs dramatically different from those of conventional balls. The newest type of ball, named Brazuca, was produced from six panels and will be used in the 2014 FIFA World Cup in Brazil. There have, however, been few studies on the aerodynamic properties of balls constructed from different numbers and shapes of panels. Hence, we used wind tunnel tests and a kick-robot to examine the relationship between the panel shape and orientation of modern soccer balls and their aerodynamic and flight characteristics. We observed a correlation between the wind tunnel test results and the actual ball trajectories, and also clarified how the panel characteristics affected the flight of the ball, which enabled prediction of the trajectory. PMID:24875291

Effect of panel shape of soccer ball on its flight characteristics

NASA Astrophysics Data System (ADS)

Hong, Sungchan; Asai, Takeshi

2014-05-01

Soccer balls are typically constructed from 32 pentagonal and hexagonal panels. Recently, however, newer balls named Cafusa, Teamgeist 2, and Jabulani were respectively produced from 32, 14, and 8 panels with shapes and designs dramatically different from those of conventional balls. The newest type of ball, named Brazuca, was produced from six panels and will be used in the 2014 FIFA World Cup in Brazil. There have, however, been few studies on the aerodynamic properties of balls constructed from different numbers and shapes of panels. Hence, we used wind tunnel tests and a kick-robot to examine the relationship between the panel shape and orientation of modern soccer balls and their aerodynamic and flight characteristics. We observed a correlation between the wind tunnel test results and the actual ball trajectories, and also clarified how the panel characteristics affected the flight of the ball, which enabled prediction of the trajectory.

Tracing dust provenance in paleoclimate records using mineralogical and isotopic fingerprints: additional clues from present-day studies

NASA Astrophysics Data System (ADS)

Bory, A. J.; Skonieczny, C.; Bout-Roumazeilles, V.; Grousset, F. E.; Biscaye, P. E.

2011-12-01

, despite the fact that these archives are located close to the highest dust-emission areas in the world. Characterization of dust provenance (using mineralogical and isotopic fingerprints) at present, which can be achieved at much higher resolution and benefit from remote sensing data and well-constrained GMC outputs, may provide valuable clues for our understanding of dust provenance in paleoclimate records. We review some investigations carried out in Greenland and Antarctica over the last decade, and present new results from the West African margin. We discuss the extent to which these present-day time series may help us calibrating our paleo-dust provenance proxies, and improving our understanding of dust provenance in paleoclimate records.

Sex-related shape dimorphism in the human radiocarpal and midcarpal joints.

PubMed

Kivell, Tracy L; Guimont, Isabelle; Wall, Christine E

2013-01-01

Previous research has revealed significant size differences between human male and female carpal bones but it is unknown if there are significant shape differences as well. This study investigated sex-related shape variation and allometric patterns in five carpal bones that make up the radiocarpal and midcarpal joints in modern humans. We found that many aspects of carpal shape (76% of all variables quantified) were similar between males and females, despite variation in size. However, 10 of the shape ratios were significantly different between males and females, with at least one significant shape difference observed in each carpal bone. Within-sex standard major axis regressions (SMA) of the numerator (i.e., the linear variables) on the denominator (i.e., the geometric mean) for each significantly different shape ratio indicated that most linear variables scaled with positive allometry in both males and females, and that for eight of the shape ratios, sex-related shape variation is associated with statistically similar sex-specific scaling relationships. Only the length of the scaphoid body and the height of the lunate triquetrum facet showed a significantly higher SMA slope in females compared with males. These findings indicate that the significant differences in the majority of the shape ratios are a function of subtle (i.e., not statistically significant) scaling differences between males and females. There are a number of potential developmental, functional, and evolutionary factors that may cause sex-related shape differences in the human carpus. The results highlight the potential for subtle differences in scaling to result in functionally significant differences in shape. Copyright © 2012 Wiley Periodicals, Inc.

Dialogue on Modernity and Modern Education in Dispute

ERIC Educational Resources Information Center

Baker, Michael; Peters, Michael A.

2012-01-01

This is a dialogue or conversation between Michael Baker (MB) and Michael A. Peters (MP) on the concept of modernity and its significance for educational theory. The dialogue took place originally as a conversation about a symposium on modernity held at the American Educational Studies Association meeting 2010. It was later developed for…

ASEM--The Modern Silk Road: Travelling Ideas for Education Reforms and Partnerships between Asia and Europe

ERIC Educational Resources Information Center

Dang, Que Anh

2013-01-01

Today the modern Silk Road between Asia and Europe is increasingly well-travelled in both directions by students, academics and policy makers. Over the last decade the European Union (EU) and the Association of South East Asian Nations (ASEAN) have been making more attempts to shape this route by creating an educational partnership through an…

Oxygen isotope ratios (18O/16O) of hemicellulose-derived sugar biomarkers in plants, soils and sediments as paleoclimate proxy II: Insight from a climate transect study

NASA Astrophysics Data System (ADS)

Tuthorn, Mario; Zech, Michael; Ruppenthal, Marc; Oelmann, Yvonne; Kahmen, Ansgar; Valle, Héctor Francisco del; Wilcke, Wolfgang; Glaser, Bruno

2014-02-01

The oxygen isotopic composition of precipitation (δ18Oprec) is well known to be a valuable (paleo-)climate proxy. Paleosols and sediments and hemicelluloses therein have the potential to serve as archives recording the isotopic composition of paleoprecipitation. In a companion paper (Zech et al., 2014) we investigated δ18Ohemicellulose values of plants grown under different climatic conditions in a climate chamber experiment. Here we present results of compound-specific δ18O analyses of arabinose, fucose and xylose extracted from modern topsoils (n = 56) along a large humid-arid climate transect in Argentina in order to answer the question whether hemicellulose biomarkers in soils reflect δ18Oprec. The results from the field replications indicate that the homogeneity of topsoils with regard to δ18Ohemicellulose is very high for most of the 20 sampling sites. Standard deviations for the field replications are 1.5‰, 2.2‰ and 1.7‰, for arabinose, fucose and xylose, respectively. Furthermore, all three hemicellulose biomarkers reveal systematic and similar trends along the climate gradient. However, the δ18Ohemicellulose values (mean of the three sugars) do not correlate positively with δ18Oprec (r = -0.54, p < 0.014, n = 20). By using a Péclet-modified Craig-Gordon (PMCG) model it can be shown that the δ18Ohemicellulose values correlate highly significantly with modeled δ18Oleaf water values (r = 0.81, p < 0.001, n = 20). This finding suggests that hemicellulose biomarkers in (paleo-)soils do not simply reflect δ18Oprec but rather δ18Oprec altered by evaporative 18O enrichment of leaf water due to evapotranspiration. According to the modeling results, evaporative 18O enrichment of leaf water is relatively low (˜10‰) in the humid northern part of the Argentinian transect and much higher (up to 19‰) in the arid middle and southern part of the transect. Model sensitivity tests corroborate that changes in relative air humidity exert a dominant

Architectural layout and vulnerability to earthquakes of housing buildings of the Modernism

NASA Astrophysics Data System (ADS)

Bostenaru, M.

2009-04-01

Bucharest, the capital of Romania, lays in a high seismic risk zone, being affected about three times a century by strong earthquakes. These occur in the mountainous region of Vrancea, at about 150 km from Bucharest, but given the fact that Bucharest is situated on alluvial soil deposits the effect of the earthquakes is stronger than in other regions of the country. In the 20th century damaging earthquakes occurred in 1940 and 1977. In both of them mostly affected were the interwar buildings, built 1920-1940 in the style of Romanian Modernism. There is little data about the 1940 earthquake, but the effects of the 1977 earthquake were extensively studied and last year 30 years since this earthquake passed. Scope of this contribution is to examine the architectural characteristics of the buildings of Modernism which lead to this high vulnerability, more precisely the criterion of zoning in the layout of the plans. This is the scope of a research project funded 2007-2010 by the European Commission with a Marie Curie Reintegration Grant; contract MERG-CT-2007-200636. Not only the buildings from Bucharest will be considered, but also from Athens, Greece and from Milan, Italy. Both Greece and Italy are countries with high seismic risk; however, Athens did not experience such damaging earthquakes until 1999 and Milan ever. The buildings of Romanian Modernism are characterised by a highly irregular shape in plan in both the overall contour as well as in the distribution of columns and beams. This is due to the following the architectural layout as well as to a lacking local seismic culture to apply at high rise buildings. It will be explained that Vrancea earthquakes, with their specific vibration periods, affect high rise buildings, and previously the style of living in Romania was the single family house, low rise, and thus less affected. Strong earthquakes used to affect slender high constructions, like the towers of churches, for example, and this is where the local

Arctic Interglacial Warmth - can Beringian paleoclimate records inform us concerning the transition we are now in?

NASA Astrophysics Data System (ADS)

Brigham-Grette, J.

2011-12-01

Contemporary change cannot be evaluated without the perspective of past rates of change in concert with a complete evaluation of associated feedbacks and forcings. Paleoclimate studies offer the only valid context for evaluating trajectories and dynamics in the climate system especially in a warming world driven by anthropogenic CO2. "If it happened before it could happen again" and it is with this adage that most of the paleoclimate community is now screaming déjà vu. The present rate of global scale warming is unprecedented within the resolution of paleorecords. High resolution terrestrial studies (lakes, tree rings and ice cores) of the last 2 ka across the Arctic clearly show that the wholesale warming of the past few decades is unprecedented and likely forced by increases in green house gas emissions. Emerging evidence of earlier warm periods over the past few million years inform us about the sensitivity of the arctic system to change, particularly the rates and magnitudes of warmth that directly impact the seasonal extent and existence of sea ice, the melt of glacial systems and changes in sea level. While there is some consensus about the rapid response of the sea-ice albedo feedback processes, it still remains difficult to model. Large changes in seasonal ice across the Arctic have been documented for parts of the early Holocene due to insolation forcing and sea ice was arguably less extensive during MIS 5e (125ka), and several other interglacials. Along with less sea ice there are data to suggest large northward range extensions of marine flora and fauna that likely accompanied changes in water mass structure. Sustained warmth during the Pliocene (especially 3.0 to 3.6 Ma) suggests several intervals when summer sea ice was absent and even the presence of winter sea ice is debated. While different research groups have each produced a variety estimates for pCO2 in mid Pliocene ranging from 280 ppm to 400 ppm, most agree that pCO2 may have been like today

A veil (hijab) as a public symbol of a Muslim woman modern identity.

PubMed

Kulenović, Tarik

2006-12-01

In this article the author explains the social role of Muslim woman in a postmodern society through a public symbol of her identity--the veil. The article's thesis is that the Muslim women's manifestation of their Islamic denomination through veiling and wearing appropriate clothes (in the case of men through growing beards and wearing clothes considered appropriate for them) signifies an expression of a new, Islamic shaped identity. This is a postmodern identity based on modernity rather than a fundamental reaction to modernity. The veil, a public symbol of Muslim identity, is often given a different meaning by its observers than the person actually wearing it. Therefore, the intention of this article is to analyze the elements of a particular, postmodern identity that a Muslim woman's veil, as a public symbol, represents.

Nuclear weapons modernizations

NASA Astrophysics Data System (ADS)

Kristensen, Hans M.

2014-05-01

This article reviews the nuclear weapons modernization programs underway in the world's nine nuclear weapons states. It concludes that despite significant reductions in overall weapons inventories since the end of the Cold War, the pace of reductions is slowing - four of the nuclear weapons states are even increasing their arsenals, and all the nuclear weapons states are busy modernizing their remaining arsenals in what appears to be a dynamic and counterproductive nuclear competition. The author questions whether perpetual modernization combined with no specific plan for the elimination of nuclear weapons is consistent with the nuclear Non-Proliferation Treaty and concludes that new limits on nuclear modernizations are needed.

The relationship between the ratio of strontium to calcium and sea-surface temperature in a modern Porites astreoides coral: Implications for using P. astreoides as a paleoclimate archive

USGS Publications Warehouse

Tess E. Busch,; Flannery, Jennifer A.; Richey, Julie N.; Stathakopoulos, Anastasios

2015-11-13

An inverse relationship has been demonstrated between water temperature and the ratio of strontium to calcium (Sr/Ca) in coral aragonite for a number of Pacific species of the genus Porites. This empirically determined relationship has been used to reconstruct past sea-surface temperature (SST) from modern and Holocene age coral archives. A study was conducted to investigate this relationship for Porites astreoides to determine the potential for using these corals as a paleotemperature archive in the Caribbean and western tropical Atlantic Ocean. Skeletal aragonite from a P. astreoides colony growing offshore of the southeast coast of Florida was subsampled with a mean temporal resolution of 14 samples per year and analyzed for Sr/Ca. The resulting Sr/Ca time series yielded well-defined annual cycles that correspond to annual growth bands in the coral. Sr/Ca was regressed against a monthly SST record from C-MAN buoy station FWYF1 (located at Fowey Rocks, Florida), resulting in the following Sr/Ca-SST relationship: Sr/Ca = –0.040*SST + 10.128 (R = –0.77). A 10-year time series of Sr/Ca-derived SST yields annual cycles with a 10–12 degree Celsius seasonal amplitude, consistent with available local instrumental records. We conclude that Sr/Ca in Porites astreoides from the Caribbean/Atlantic region has high potential for developing subannually resolved modern and recent Holocene SST records.

Dynamic Hydrological Discharge Modelling for Fully Coupled Paleoclimate Runs of the Last Glacial Cycle

NASA Astrophysics Data System (ADS)

Riddick, Thomas; Brovkin, Victor; Hagemann, Stefan; Mikolajewicz, Uwe

2017-04-01

The continually evolving large ice sheets present in the Northern Hemisphere during the last glacial cycle caused significant changes to river pathways both through directly blocking rivers and through glacial isostatic adjustment. These river pathway changes are believed to of had a significant impact on the evolution of ocean circulation through changing the pattern of fresh water discharge into the oceans. A fully coupled ESM simulation of the last glacial cycle thus requires a hydrological discharge model that uses a set of river pathways that evolve with the earth's changing orography while being able to reproduce the known present-day river network given the present-day orography. Here we present a method for dynamically modelling hydrological discharge that meets such requirements by applying relative manual corrections to an evolving fine scale orography (accounting for the changing ice sheets and isostatic rebound) each time the river directions are recalculated. The corrected orography thus produced is then used to create a set of fine scale river pathways and these are then upscaled to a course scale. An existing present-day hydrological discharge model within the JSBACH3 land surface model is run using the course scale river pathways generated. This method will be used in fully coupled paleoclimate runs made using MPI-ESM1 as part of the PalMod project. Tests show this procedure reproduces the known present-day river network to a sufficient degree of accuracy.

Nuclear weapons modernizations

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

Kristensen, Hans M.

This article reviews the nuclear weapons modernization programs underway in the world's nine nuclear weapons states. It concludes that despite significant reductions in overall weapons inventories since the end of the Cold War, the pace of reductions is slowing - four of the nuclear weapons states are even increasing their arsenals, and all the nuclear weapons states are busy modernizing their remaining arsenals in what appears to be a dynamic and counterproductive nuclear competition. The author questions whether perpetual modernization combined with no specific plan for the elimination of nuclear weapons is consistent with the nuclear Non-Proliferation Treaty and concludesmore » that new limits on nuclear modernizations are needed.« less

Loop shaping design for tracking performance in machine axes.

PubMed

Schinstock, Dale E; Wei, Zhouhong; Yang, Tao

2006-01-01

A modern interpretation of classical loop shaping control design methods is presented in the context of tracking control for linear motor stages. Target applications include noncontacting machines such as laser cutters and markers, water jet cutters, and adhesive applicators. The methods are directly applicable to the common PID controller and are pertinent to many electromechanical servo actuators other than linear motors. In addition to explicit design techniques a PID tuning algorithm stressing the importance of tracking is described. While the theory behind these techniques is not new, the analysis of their application to modern systems is unique in the research literature. The techniques and results should be important to control practitioners optimizing PID controller designs for tracking and in comparing results from classical designs to modern techniques. The methods stress high-gain controller design and interpret what this means for PID. Nothing in the methods presented precludes the addition of feedforward control methods for added improvements in tracking. Laboratory results from a linear motor stage demonstrate that with large open-loop gain very good tracking performance can be achieved. The resultant tracking errors compare very favorably to results from similar motions on similar systems that utilize much more complicated controllers.

Patterns in leaf morphological traits of Chinese woody plants and the application for paleoclimate reconstruction

NASA Astrophysics Data System (ADS)

Li, Yaoqi; Wang, Zhiheng

2017-04-01

Leaf morphological traits (LMTs) directly influence carbon-uptake and water-loss of plants in different habitats, and hence can be sensitive indicators of plant interaction with climate. The relationships between community-aggregated LMTs and their surrounding climate have been used to reconstruct paleoclimate. However, the uncertainties in its application remain poorly explored. Using distribution maps and LMTs data (leaf margin states, leaf length, leaf width, and length-width product/ratio) of 10480 Chinese woody dicots and dated family-level phylogenies, we demonstrated the variations of LMTs in geographical patterns, and analyzed their relationships with climate across different life-forms (evergreen and deciduous; trees, shrubs and lianas) and species quartiles with different family-ages. Results showed that from southern to northern China, leaves became shorter and narrower, while leaf length-width ratio increased and toothed-margin percentage decreased. Our results revealed great uncertainties in leaf margin-temperature relationships induced by life-form, precipitation and evolutionary history, and suggested that the widely-used method, leaf margin analysis, should be applied cautiously on paleotemperature reconstruction. Differently, mean leaf size responded tightly to spatial variations in annual evapotranspiration (AET) and primary productivity (GPP and NPP), and these relationships remained constant across different life-forms and evolutionary history, suggesting that leaf size could be a useful surrogate for paleo primary productivity.

Reconstructing paleoclimate fields using online data assimilation with a linear inverse model

NASA Astrophysics Data System (ADS)

Perkins, Walter A.; Hakim, Gregory J.

2017-05-01

We examine the skill of a new approach to climate field reconstructions (CFRs) using an online paleoclimate data assimilation (PDA) method. Several recent studies have foregone climate model forecasts during assimilation due to the computational expense of running coupled global climate models (CGCMs) and the relatively low skill of these forecasts on longer timescales. Here we greatly diminish the computational cost by employing an empirical forecast model (linear inverse model, LIM), which has been shown to have skill comparable to CGCMs for forecasting annual-to-decadal surface temperature anomalies. We reconstruct annual-average 2 m air temperature over the instrumental period (1850-2000) using proxy records from the PAGES 2k Consortium Phase 1 database; proxy models for estimating proxy observations are calibrated on GISTEMP surface temperature analyses. We compare results for LIMs calibrated using observational (Berkeley Earth), reanalysis (20th Century Reanalysis), and CMIP5 climate model (CCSM4 and MPI) data relative to a control offline reconstruction method. Generally, we find that the usage of LIM forecasts for online PDA increases reconstruction agreement with the instrumental record for both spatial fields and global mean temperature (GMT). Specifically, the coefficient of efficiency (CE) skill metric for detrended GMT increases by an average of 57 % over the offline benchmark. LIM experiments display a common pattern of skill improvement in the spatial fields over Northern Hemisphere land areas and in the high-latitude North Atlantic-Barents Sea corridor. Experiments for non-CGCM-calibrated LIMs reveal region-specific reductions in spatial skill compared to the offline control, likely due to aspects of the LIM calibration process. Overall, the CGCM-calibrated LIMs have the best performance when considering both spatial fields and GMT. A comparison with the persistence forecast experiment suggests that improvements are associated with the linear

FOREWORD: Shape Memory and Related Technologies

NASA Astrophysics Data System (ADS)

Liu, Yong

2005-10-01

The International Symposium on Shape Memory and Related Technologies (SMART2004) successfully took place in Singapore from November 24 to 26, 2004. SMART2004 aimed to provide a forum for presenting and discussing recent developments in the processing, characterization, application and performance prediction of shape memory materials, particularly shape memory alloys and magnetic shape memory materials. In recent years, we have seen a surge in the research and application of shape memory materials. This is due on the one hand to the successful applications of shape memory alloys (SMAs), particularly NiTi (nitinol), in medical practices and, on the other hand, to the discovery of magnetic shape memory (MSM) materials (or, ferromagnetic shape memory alloys, FSMAs). In recent years, applications of SMAs in various engineering practices have flourished owing to the unique combination of novel properties including high power density related to shape recovery, superelasticity with tunable hysteresis, high damping capacity combined with good fatigue resistance, excellent wear resistance due to unconventional deformation mechanisms (stress-induced phase transformation and martensite reorientation), and excellent biocompatibility and anticorrosion resistance, etc. In~the case of MSMs (or FSMAs), their giant shape change in a relatively low magnetic field has great potential to supplement the traditional actuation mechanisms and to have a great impact on the world of modern technology. Common mechanisms existing in both types of materials, namely thermoelastic phase transformation, martensite domain switching and their controlling factors, are of particular interest to the scientific community. Despite some successful applications, some fundamental issues remain unsatisfactorily understood. This conference hoped to link the fundamental research to engineering practices, and to further identify remaining problems in order to further promote the applications of shape memory

Understanding global climate change: paleoclimate perspective from the world's highest mountains.

PubMed

Thompson, Lonnie G

2010-06-01

tourism. As these glaciers are disappearing, we are also losing very valuable paleoclimate archives.

Genomic validation of the differential preservation of population history in modern human cranial anatomy.

PubMed

Reyes-Centeno, Hugo; Ghirotto, Silvia; Harvati, Katerina

2017-01-01

In modern humans, the significant correlation between neutral genetic loci and cranial anatomy suggests that the cranium preserves a population history signature. However, there is disagreement on whether certain parts of the cranium preserve this signature to a greater degree than other parts. It is also unclear how different quantitative measures of phenotype affect the association of genetic variation and anatomy. Here, we revisit these matters by testing the correlation of genetic distances and various phenotypic distances for ten modern human populations. Geometric morphometric shape data from the crania of adult individuals (n = 224) are used to calculate phenotypic P ST , Procrustes, and Mahalanobis distances. We calculate their correlation to neutral genetic distances, F ST , derived from single nucleotide polymorphisms (SNPs). We subset the cranial data into landmark configurations that include the neurocranium, the face, and the temporal bone in order to evaluate whether these cranial regions are differentially correlated to neutral genetic variation. Our results show that P ST , Mahalanobis, and Procrustes distances are correlated with F ST distances to varying degrees. They indicate that overall cranial shape is significantly correlated with neutral genetic variation. Of the component parts examined, P ST distances for both the temporal bone and the face have a stronger association with F ST distances than the neurocranium. When controlling for population divergence time, only the whole cranium and the temporal bone have a statistically significant association with F ST distances. Our results confirm that the cranium, as a whole, and the temporal bone can be used to reconstruct modern human population history. © 2016 Wiley Periodicals, Inc.

The Changing Nature of Modernization Discourses in Documentary Films.

PubMed

Tabernero, Carlos

2018-03-01

Argument Franco's fascist regime in Spain (1939-1975) offers the possibility of exploring the complex relationship between media communication practices and the processes of production, circulation, and management of knowledge. The regime persistently used film, and later on television, as indoctrination and disciplining devices. These media thus served to shape the regime's representation, which largely relied on the generation of positive attitudes of adherence to the rulers through people's submission and obedience to experts. This article examines the changing nature of modernization discourses and practices, as a fundamental element of the regime's propaganda strategies, and as portrayed in documentaries produced under its rule. The rhetoric of modernization involved an explicit deficit model of knowledge management, which aimed at legitimating the regime's deeds and policies in its first decades, as we shall see regarding colonial-medical documentaries produced for the official newsreel in the 1940s. However, the focus of such rhetoric, despite its enduring political aims, had to somehow open up as the relationship between experts and non-experts changed, both in epistemological and practical terms, such as in wildlife documentary films produced for television in the 1970s, the regime's last decade.

Acropora interbranch skeleton Sr/Ca ratios: Evaluation of a potential new high-resolution paleothermometer

NASA Astrophysics Data System (ADS)

Sadler, James; Nguyen, Ai D.; Leonard, Nicole D.; Webb, Gregory E.; Nothdurft, Luke D.

2016-04-01

The majority of coral geochemistry-based paleoclimate reconstructions in the Indo-Pacific are conducted on selectively cored colonies of massive Porites. This restriction to a single genus may make it difficult to amass the required paleoclimate data for studies that require deep reef coring techniques. Acropora, however, is a highly abundant coral genus in both modern and fossil reef systems and displays potential as a novel climate archive. Here we present a calibration study for Sr/Ca ratios recovered from interbranch skeleton in corymbose Acropora colonies from Heron Reef, southern Great Barrier Reef. Significant intercolony differences in absolute Sr/Ca ratios were normalized by producing anomaly plots of both coral geochemistry and instrumental water temperature records. Weighted linear regression of these anomalies from the lagoon and fore-reef slope provide a sensitivity of -0.05 mmol/mol °C-1, with a correlation coefficient (r2 = 0.65) comparable to those of genera currently used in paleoclimate reconstructions. Reconstructions of lagoon and reef slope mean seasonality in water temperature accurately identify the greater seasonal amplitude observed in the lagoon of Heron Reef. A longer calibration period is, however, required for reliable reconstructions of annual mean water temperatures.

A geometric morphometric study of regional differences in the ontogeny of the modern human facial skeleton.

PubMed

Vioarsdóttir, Una Strand; O'Higgins, Paul; Stringer, Chris

2002-09-01

This study examines interpopulation variations in the facial skeleton of 10 modern human populations and places these in an ontogenetic perspective. It aims to establish the extent to which the distinctive features of adult representatives of these populations are present in the early post natal period and to what extent population differences in ontogenetic scaling and allometric trajectories contribute to distinct facial forms. The analyses utilize configurations of facial landmarks and are carried out using geometric morphometric methods. The results of this study show that modern human populations can be distinguished based on facial shape alone, irrespective of age or sex, indicating the early presence of differences. Additionally, some populations have statistically distinct facial ontogenetic trajectories that lead to the development of further differences later in ontogeny. We conclude that population-specific facial morphologies develop principally through distinctions in facial shape probably already present at birth and further accentuated and modified to variable degrees during growth. These findings raise interesting questions regarding the plasticity of facial growth patterns in modern humans. Further, they have important implications in relation to the study of growth in the face of fossil hominins and in relation to the possibility of developing effective discriminant functions for the identification of population affinities of immature facial skeletal material. Such tools would be of value in archaeological, forensic and anthropological applications. The findings of this study underline the need to examine more deeply, and in more detail, the ontogenetic basis of other causes of craniometric variation, such as sexual dimorphism and hominin species differentiation.

Oval Window Size and Shape: a Micro-CT Anatomical Study With Considerations for Stapes Surgery.

PubMed

Zdilla, Matthew J; Skrzat, Janusz; Kozerska, Magdalena; Leszczyński, Bartosz; Tarasiuk, Jacek; Wroński, Sebastian

2018-06-01

The oval window is an important structure with regard to stapes surgeries, including stapedotomy for the treatment of otosclerosis. Recent study of perioperative imaging of the oval window has revealed that oval window niche height can indicate both operative difficulty and subjective discomfort during otosclerosis surgery. With regard to shape, structures incorporated into the oval window niche, such as cartilage grafts, must be compatible with the shape of the oval window. Despite the clinical importance of the oval window, there is little information regarding its size and shape. This study assessed oval window size and shape via micro-computed tomography paired with modern morphometric methodology in the fetal, infant, child, and adult populations. Additionally, the study compared oval window size and shape between sexes and between left- and right-sided ears. No significant differences were found among traditional morphometric parameters among age groups, sides, or sexes. However, geometric morphometric methods revealed shape differences between age groups. Further, geometric morphometric methods provided the average oval window shape and most-likely shape variance. Beyond demonstrating oval window size and shape variation, the results of this report will aid in identifying patients among whom anatomical variation may contribute to surgical difficulty and surgeon discomfort, or otherwise warrant preoperative adaptations for the incorporation of materials into and around the oval window.

Design of a shape-memory alloy actuated macro-scale morphing aircraft mechanism

NASA Astrophysics Data System (ADS)

Manzo, Justin; Garcia, Ephrahim; Wickenheiser, Adam; Horner, Garnett C.

2005-05-01

As more alternative, lightweight actuators have become available, the conventional fixed-wing configuration seen on modern aircraft is under investigation for efficiency on a broad scale. If an aircraft could be designed with multiple functional equilibria of drastically varying aerodynamic parameters, one craft capable of 'morphing' its shape could be used to replace two or three designed with particular intentions. One proposed shape for large-scale (geometry change on the same order of magnitude as wingspan) morphing is the Hyper-Elliptical Cambered Span (HECS) wing, designed at NASA Langley to be implemented on an unmanned aerial vehicle (UAV). Proposed mechanisms to accomplish the spanwise curvature (in the y-z plane of the craft) that allow near-continuous bending of the wing are narrowed to a tendon-based DC motor actuated system, and a shape memory alloy-based (SMA) mechanism. At Cornell, simulations and wind tunnel experiments assess the validity of the HECS wing as a potential shape for a blended-wing body craft with the potential to effectively serve the needs of two conventional UAVs, and analyze the energetics of actuation associated with a morphing maneuver accomplished with both a DC motor and SMA wire.

SHAPE Selection (SHAPES) enrich for RNA structure signal in SHAPE sequencing-based probing data

PubMed Central

Poulsen, Line Dahl; Kielpinski, Lukasz Jan; Salama, Sofie R.; Krogh, Anders; Vinther, Jeppe

2015-01-01

Selective 2′ Hydroxyl Acylation analyzed by Primer Extension (SHAPE) is an accurate method for probing of RNA secondary structure. In existing SHAPE methods, the SHAPE probing signal is normalized to a no-reagent control to correct for the background caused by premature termination of the reverse transcriptase. Here, we introduce a SHAPE Selection (SHAPES) reagent, N-propanone isatoic anhydride (NPIA), which retains the ability of SHAPE reagents to accurately probe RNA structure, but also allows covalent coupling between the SHAPES reagent and a biotin molecule. We demonstrate that SHAPES-based selection of cDNA–RNA hybrids on streptavidin beads effectively removes the large majority of background signal present in SHAPE probing data and that sequencing-based SHAPES data contain the same amount of RNA structure data as regular sequencing-based SHAPE data obtained through normalization to a no-reagent control. Moreover, the selection efficiently enriches for probed RNAs, suggesting that the SHAPES strategy will be useful for applications with high-background and low-probing signal such as in vivo RNA structure probing. PMID:25805860

Modern Chinese: History and Sociolinguistics.

ERIC Educational Resources Information Center

Chen, Ping

This book presents a comprehensive and up-to-date account of the development of modern Chinese from the late 19th century up to the 1990s, concentrating on three major aspects: modern spoken Chinese, modern written Chinese, and the modern Chinese writing system. It describes and analyzes in detail, from historical and sociolinguistic perspectives,…

Microscopic Identification of Prokaryotes in Modern and Ancient Halite, Saline Valley and Death Valley, California

NASA Astrophysics Data System (ADS)

Schubert, Brian A.; Lowenstein, Tim K.; Timofeeff, Michael N.

2009-06-01

Primary fluid inclusions in halite crystallized in Saline Valley, California, in 1980, 2004-2005, and 2007, contain rod- and coccoid-shaped microparticles the same size and morphology as archaea and bacteria living in modern brines. Primary fluid inclusions from a well-dated (0-100,000 years), 90 m long salt core from Badwater Basin, Death Valley, California, also contain microparticles, here interpreted as halophilic and halotolerant prokaryotes. Prokaryotes are distinguished from crystals on the basis of morphology, optical properties (birefringence), and uniformity of size. Electron micrographs of microparticles from filtered modern brine (Saline Valley), dissolved modern halite crystals (Saline Valley), and dissolved ancient halite crystals (Death Valley) support in situ microscopic observations that prokaryotes are present in fluid inclusions in ancient halite. In the Death Valley salt core, prokaryotes in fluid inclusions occur almost exclusively in halite precipitated in perennial saline lakes 10,000 to 35,000 years ago. This suggests that trapping and preservation of prokaryotes in fluid inclusions is influenced by the surface environment in which the halite originally precipitated. In all cases, prokaryotes in fluid inclusions in halite from the Death Valley salt core are miniaturized (<1 μm diameter cocci, <2.5 μm long, very rare rod shapes), which supports interpretations that the prokaryotes are indigenous to the halite and starvation survival may be the normal response of some prokaryotes to entrapment in fluid inclusions for millennia. These results reinforce the view that fluid inclusions in halite and possibly other evaporites are important repositories of microbial life and should be carefully examined in the search for ancient microorganisms on Earth, Mars, and elsewhere in the Solar System.

Casebooks in Early Modern England:

PubMed Central

Kassell, Lauren

2014-01-01

summary Casebooks are the richest sources that we have for encounters between early modern medical practitioners and their patients. This article compares astrological and medical records across two centuries, focused on England, and charts developments in the ways in which practitioners kept records and reflected on their practices. Astrologers had a long history of working from particular moments, stellar configurations, and events to general rules. These practices required systematic notation. Physicians increasingly modeled themselves on Hippocrates, recording details of cases as the basis for reasoned expositions of the histories of disease. Medical records, as other scholars have demonstrated, shaped the production of medical knowledge. Instead, this article focuses on the nature of casebooks as artifacts of the medical encounter. It establishes that casebooks were serial records of practice, akin to diaries, testimonials, and registers; identifies extant English casebooks and the practices that led to their production and preservation; and concludes that the processes of writing, ordering, and preserving medical records are as important for understanding the medical encounter as the records themselves. PMID:25557513

Head-and-face shape variations of U.S. civilian workers

PubMed Central

Zhuang, Ziqing; Shu, Chang; Xi, Pengcheng; Bergman, Michael; Joseph, Michael

2016-01-01

The objective of this study was to quantify head-and-face shape variations of U.S. civilian workers using modern methods of shape analysis. The purpose of this study was based on previously highlighted changes in U.S. civilian worker head-and-face shape over the last few decades – touting the need for new and better fitting respirators – as well as the study's usefulness in designing more effective personal protective equipment (PPE) – specifically in the field of respirator design. The raw scan three-dimensional (3D) data for 1169 subjects were parameterized using geometry processing techniques. This process allowed the individual scans to be put in correspondence with each other in such a way that statistical shape analysis could be performed on a dense set of 3D points. This process also cleaned up the original scan data such that the noise was reduced and holes were filled in. The next step, statistical analysis of the variability of the head-and-face shape in the 3D database, was conducted using Principal Component Analysis (PCA) techniques. Through these analyses, it was shown that the space of the head-and-face shape was spanned by a small number of basis vectors. Less than 50 components explained more than 90% of the variability. Furthermore, the main mode of variations could be visualized through animating the shape changes along the PCA axes with computer software in executable form for Windows XP. The results from this study in turn could feed back into respirator design to achieve safer, more efficient product style and sizing. Future study is needed to determine the overall utility of the point cloud-based approach for the quantification of facial morphology variation and its relationship to respirator performance. PMID:23399025

Head-and-face shape variations of U.S. civilian workers.

PubMed

Zhuang, Ziqing; Shu, Chang; Xi, Pengcheng; Bergman, Michael; Joseph, Michael

2013-09-01

The objective of this study was to quantify head-and-face shape variations of U.S. civilian workers using modern methods of shape analysis. The purpose of this study was based on previously highlighted changes in U.S. civilian worker head-and-face shape over the last few decades - touting the need for new and better fitting respirators - as well as the study's usefulness in designing more effective personal protective equipment (PPE) - specifically in the field of respirator design. The raw scan three-dimensional (3D) data for 1169 subjects were parameterized using geometry processing techniques. This process allowed the individual scans to be put in correspondence with each other in such a way that statistical shape analysis could be performed on a dense set of 3D points. This process also cleaned up the original scan data such that the noise was reduced and holes were filled in. The next step, statistical analysis of the variability of the head-and-face shape in the 3D database, was conducted using Principal Component Analysis (PCA) techniques. Through these analyses, it was shown that the space of the head-and-face shape was spanned by a small number of basis vectors. Less than 50 components explained more than 90% of the variability. Furthermore, the main mode of variations could be visualized through animating the shape changes along the PCA axes with computer software in executable form for Windows XP. The results from this study in turn could feed back into respirator design to achieve safer, more efficient product style and sizing. Future study is needed to determine the overall utility of the point cloud-based approach for the quantification of facial morphology variation and its relationship to respirator performance. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Middle and Late Pleistocene glaciations in the southwestern Pamir and their effects on topography

USGS Publications Warehouse

Stubner, Konstanze; Grin, Elena; Hidy, Alan J.; Schaller, Mirjam; Gold, Ryan D.; Ratschbacher, Lothar; Ehlers, Todd

2017-01-01

Glacial chronologies provide insight into the evolution of paleo-landscapes, paleoclimate, topography, and the erosion processes that shape mountain ranges. In the Pamir of Central Asia, glacial morphologies and deposits indicate extensive past glaciations, whose timing and extent remain poorly constrained. Geomorphic data and 15 new 10Be exposure ages from moraine boulders and roches moutonnées in the southwestern Pamir document multiple Pleistocene glacial stages. The oldest exposure ages, , underestimate the age of the earliest preserved glacial advance and imply that the modern relief of the southwestern Pamir (peaks at ∼5000–6000 m a.s.l.; valleys at ∼2000–3000 m a.s.l.) already existed in the late Middle Pleistocene. Younger exposure ages (∼40–80 ka, ∼30 ka) complement the existing Central Asian glacial chronology and reflect successively less extensive Late Pleistocene glaciations. The topography of the Pamir and the glacial chronologies suggest that, in the Middle Pleistocene, an ice cap or ice field occupied the eastern Pamir high-altitude plateau, whereas westward flowing valley glaciers incised the southwestern Pamir. Since the Late Pleistocene deglaciation, the rivers of the southwestern Pamir adjusted to the glacially shaped landscape. Localized rapid fluvial incision and drainage network reorganization reflect the transient nature of the deglaciated landscape.

Varieties of second modernity: the cosmopolitan turn in social and political theory and research.

PubMed

Beck, Ulrich; Grande, Edgar

2010-09-01

The theme of this special issue is the necessity of a cosmopolitan turn in social and political theory. The question at the heart of this introductory chapter takes the challenge of 'methodological cosmopolitanism', already addressed in a Special Issue on Cosmopolitan Sociology in this journal (Beck and Sznaider 2006), an important step further: How can social and political theory be opened up, theoretically as well as methodologically and normatively, to a historically new, entangled Modernity which threatens its own foundations? How can it account for the fundamental fragility, the mutability of societal dynamics (of unintended side effects, domination and power), shaped by the globalization of capital and risks at the beginning of the twenty-first century? What theoretical and methodological problems arise and how can they be addressed in empirical research? In the following, we will develop this 'cosmopolitan turn' in four steps: firstly, we present the major conceptual tools for a theory of cosmopolitan modernities; secondly, we de-construct Western modernity by using examples taken from research on individualization and risk; thirdly, we address the key problem of methodological cosmopolitanism, namely the problem of defining the appropriate unit of analysis; and finally,we discuss normative questions, perspectives, and dilemmas of a theory of cosmopolitan modernities, in particular problems of political agency and prospects of political realization.

Measuring the shapes of macromolecules – and why it matters

PubMed Central

Li, Jie; Mach, Paul; Koehl, Patrice

2013-01-01

The molecular basis of life rests on the activity of biological macromolecules, mostly nucleic acids and proteins. A perhaps surprising finding that crystallized over the last handful of decades is that geometric reasoning plays a major role in our attempt to understand these activities. In this paper, we address this connection between geometry and biology, focusing on methods for measuring and characterizing the shapes of macromolecules. We briefly review existing numerical and analytical approaches that solve these problems. We cover in more details our own work in this field, focusing on the alpha shape theory as it provides a unifying mathematical framework that enable the analytical calculations of the surface area and volume of a macromolecule represented as a union of balls, the detection of pockets and cavities in the molecule, and the quantification of contacts between the atomic balls. We have shown that each of these quantities can be related to physical properties of the molecule under study and ultimately provides insight on its activity. We conclude with a brief description of new challenges for the alpha shape theory in modern structural biology. PMID:24688748

Philosophical midwifery and the birthpangs of modern cosmology

NASA Astrophysics Data System (ADS)

Gale, George; Urani, John

1993-01-01

Philosophical considerations sometimes direct developments in physics. Such influence most frequently operates during the genesis of new fields. The birth of modern cosmology provides clear evidence of the interaction between philosophical issues and the shape and direction of a new physical discipline. Philosophical controversy between E. A. Milne and other astrophysicists, including A. S. Eddington, James Jeans, and H. P. Robertson, directly affected the models, methods, and very nature of cosmological science for future generations. Today's standard space-time metric, for example, resulted from responses by Robertson and A. G. Walker to philosophical challenges presented in Milne's proposals to scrap the very idea of expanding ``space.'' Analysis of published works, unpublished manuscripts and correspondence, and personal interviews illustrates the role philosophical considerations played in development of this new field in physics.

Numerical investigation of galloping instabilities in Z-shaped profiles.

PubMed

Gomez, Ignacio; Chavez, Miguel; Alonso, Gustavo; Valero, Eusebio

2014-01-01

Aeroelastic effects are relatively common in the design of modern civil constructions such as office blocks, airport terminal buildings, and factories. Typical flexible structures exposed to the action of wind are shading devices, normally slats or louvers. A typical cross-section for such elements is a Z-shaped profile, made out of a central web and two-side wings. Galloping instabilities are often determined in practice using the Glauert-Den Hartog criterion. This criterion relies on accurate predictions of the dependence of the aerodynamic force coefficients with the angle of attack. The results of a parametric analysis based on a numerical analysis and performed on different Z-shaped louvers to determine translational galloping instability regions are presented in this paper. These numerical analysis results have been validated with a parametric analysis of Z-shaped profiles based on static wind tunnel tests. In order to perform this validation, the DLR TAU Code, which is a standard code within the European aeronautical industry, has been used. This study highlights the focus on the numerical prediction of the effect of galloping, which is shown in a visible way, through stability maps. Comparisons between numerical and experimental data are presented with respect to various meshes and turbulence models.

Climate History of the Southern San Joaquin Valley of California, USA: Authentic Paleoclimate Research with K-12 Teachers

NASA Astrophysics Data System (ADS)

Baron, D.; Negrini, R. M.; Palacios-Fest, M. R.; Auffant, K.

2006-12-01

For three summers, the Department of Geology at California State University, Bakersfield (CSUB) has invited teachers from local schools to participate in a research program that is investigating the climate history of the San Joaquin Valley of California. In each 4-week summer project, three elementary/middle school teachers and three high school teachers worked with CSUB faculty, undergraduate geology students, and a small group of high school students. The research centers around the analysis of 50-foot (15 m) sediment cores from two locations in the Tulare Lake basin. These cores preserve a regional climate record dating back to about 35,000 years before the present. Research tasks include the description of sediments from the cores for parameters such as grain size, color, and mineralogy. Sediment analyses include total organic and total inorganic carbon, as well as magnetic susceptibility. Ostracode shells were separated from the sediments, ostracode species present were identified and their abundances determined. Each teacher was put in charge of the description and analysis of several 5-foot (1.5 m) core segments. Each teacher was the leader of a research group including a CSUB geology student and one or two high school students. The groups were responsible for all aspects of the description and analysis of their core segments. They were also in charge of the paleoclimate interpretations and the presentation of their research results at the end of the summer projects. Surveys conducted before and after the summer program indicate that teacher's knowledge of climate change and regional geology, as well as their confidence in teaching Earth science at their schools increased. Follow- up surveys conducted a year after the first summer program indicate that the research experience had a lasting positive impact on teacher's confidence and their enthusiasm for teaching Earth science. Several of the teachers have developed lesson plans and/or field trips for their

A high altitude paleoclimate record from an ice core retrieved at the northern margin of the Mediterranean basin

NASA Astrophysics Data System (ADS)

Gabrielli, P.; Barbante, C.; Carturan, L.; Davis, M. E.; Dalla Fontana, G.; Dreossi, G.; Dinale, R.; Draga, G.; Gabrieli, J.; Kehrwald, N. M.; Mair, V.; Mikhalenko, V.; Oeggl, K.; Schotterer, U.; Seppi, R.; Spolaor, A.; Stenni, B.; Thompson, L. G.; Tonidandel, D.

2013-12-01

Atmospheric temperatures in the Alps are increasing at twice the global rate and this change may be amplified at the highest elevations. There is a scarcity of paleo-climate information from high altitudes to place this current rapid climate change in a paleo-perspective. The 'Ortles Project' is an international scientific effort gathering institutes from six nations with the primary goal of obtaining a high altitude paleo-climate record in the Mediterranean area. In 2011 four ice cores were extracted from Alto dell'Ortles (3859 m, South Tyrol, Italy) the highest glacier in the eastern Alps. This site is located ~30 km away from where the famous ~5.2 kyr old Tyrolean Ice Man was discovered emerging from an ablating ice field (Hauslabjoch, 3210 m) in 1991. The good state of conservation of this mummy suggested that the current warming trend is unprecedented in South Tyrol during the late Holocene and that unique prehistoric ice was still present in this region. During the ice core drilling operations we found that the glacier Alto dell'Ortles shows a very unusual thermic behavior as it is transitioning from a cold to a temperate state. In fact, below a 30 meter thick temperate firn portion, we observed cold ice layers sitting on a frozen bedrock (-2.8 C). These represent remnants of the colder climate before ~1980 AD, when an instrumental record indicates a ~2 C lower temperature in this area during the period 1864-1980 AD. By analyzing one of the Ortles cores for stable isotopes, dust and major ions, we found an annually preserved climatic signal embedded in the deep cold ice of this glacier. Alto dell'Ortles is therefore the first low-accumulation (850 mm w.e. per year) alpine drilling site where both winter and summer layers can be identified. Preliminary annual layer counting and two absolute time markers suggest that the time period covered by the Ortles ice cores spans from several centuries to a few millennia. In particular, a Larix (larch) leaf discovered at

Superordinate Shape Classification Using Natural Shape Statistics

ERIC Educational Resources Information Center

Wilder, John; Feldman, Jacob; Singh, Manish

2011-01-01

This paper investigates the classification of shapes into broad natural categories such as "animal" or "leaf". We asked whether such coarse classifications can be achieved by a simple statistical classification of the shape skeleton. We surveyed databases of natural shapes, extracting shape skeletons and tabulating their…

Laetoli footprints reveal bipedal gait biomechanics different from those of modern humans and chimpanzees

PubMed Central

Demes, Brigitte; Richmond, Brian G.

2016-01-01

Bipedalism is a key adaptation that shaped human evolution, yet the timing and nature of its evolution remain unclear. Here we use new experimentally based approaches to investigate the locomotor mechanics preserved by the famous Pliocene hominin footprints from Laetoli, Tanzania. We conducted footprint formation experiments with habitually barefoot humans and with chimpanzees to quantitatively compare their footprints to those preserved at Laetoli. Our results show that the Laetoli footprints are morphologically distinct from those of both chimpanzees and habitually barefoot modern humans. By analysing biomechanical data that were collected during the human experiments we, for the first time, directly link differences between the Laetoli and modern human footprints to specific biomechanical variables. We find that the Laetoli hominin probably used a more flexed limb posture at foot strike than modern humans when walking bipedally. The Laetoli footprints provide a clear snapshot of an early hominin bipedal gait that probably involved a limb posture that was slightly but significantly different from our own, and these data support the hypothesis that important evolutionary changes to hominin bipedalism occurred within the past 3.66 Myr. PMID:27488647

"Reinventing" Techniques for the Estimation of the Area of Irregular Plane Figures: From the Eighteenth Century to the Modern Classroom

ERIC Educational Resources Information Center

Papadopoulos, Ioannis

2010-01-01

The issue of the area of irregular shapes is absent from the modern mathematical textbooks in elementary education in Greece. However, there exists a collection of books written for educational purposes by famous Greek scholars dating from the eighteenth century, which propose certain techniques concerning the estimation of the area of such…

The impact of cigarette pack shape, size and opening: evidence from tobacco company documents.

PubMed

Kotnowski, Kathy; Hammond, David

2013-09-01

To use tobacco industry documents on cigarette pack shape, size and openings to identify industry findings on associations with brand imagery, product attributes, consumer perceptions and behaviour. Internal tobacco industry research and marketing documents obtained through court disclosure contained in the Legacy Tobacco Documents Library were searched using keywords related to pack shapes, sizes and opening methods. The search identified 66 documents related to consumer research and marketing plans on pack shape, size and openings, drawn from 1973 to 2002. Industry research consistently found that packs that deviated from the traditional flip-top box projected impressions of 'modern', 'elegant' and 'unique' brand imagery. Alternative pack shape and openings were identified as an effective means to communicate product attributes, particularly with regard to premium quality and smooth taste. Consumer studies consistently found that pack shape, size and opening style influenced perceptions of reduced product harm, and were often used to communicate a 'lighter' product. Slim, rounded, oval and booklet packs were found to be particularly appealing among young adults, and several studies demonstrated increased purchase interest for tobacco products presented in novel packaging shape or opening. Evidence from consumer tracking reports and company presentations indicate that pack innovations in shape or opening method increased market share of brands. Consumer research by the tobacco industry between 1973 and 2002 found that variations in packaging shape, size and opening method could influence brand appeal and risk perceptions and increase cigarette sales. © 2013 Society for the Study of Addiction.

MATERIALS FOR MODERNIZATION.

ERIC Educational Resources Information Center

JACKSON, R. GRAHAM

CHOICES AND ISSUES IN SELECTING MATERIALS FOR MODERNIZATION OF SCHOOL BUILDINGS ARE DISCUSSED IN THIS REPORT. BACKGROUND INFORMATION IS INTRODUCED IN TERMS OF REASONS FOR ABANDONMENT, THE CAUSES AND EFFECTS OF SCHOOL BUILDING OBSOLESCENCE, AND PROBLEMS IN THE MODERNIZATION PROCESS. INTERIOR PARTITIONS ARE DISCUSSED IN TERMS OF BUILDING MATERIALS,…

Towards Better Calibration of Modern Palynological Data against Climate: A Case Study in Osaka Bay, Japan

NASA Astrophysics Data System (ADS)

Kitaba, I.; Nakagawa, T.; McClymont, E.; Dettman, D. L.; Yamada, K.; Takemura, K.; Hyodo, M.

2014-12-01

Many of the difficulties in the pollen fossil-based paleoclimate reconstruction in coastal regions derive from the complex sedimentary processes of the near-shore environment. In order to examine this problem, we carried out pollen analysis of surface sediments collected from 35 sites in Osaka Bay, Japan. Using the biomisation method, the surrounding vegetation was accurately reconstructed at all sites. Applying the modern analogue technique to the same data, however, led to reconstructed temperatures that were lower by ca. 5 deg. C and precipitation amounts higher by ca. 5000 mm than the current sea level climate of the region. The range of reconstructed values was larger than the reconstruction error associated with the method. The principal component analysis shows that the surface pollen variation in Osaka Bay reflects sedimentary processes. This significant error associated with the quantitative climatic reconstruction using pollen data is attributed to the fact that the pollen assemblage is not determined solely by climate but reflects non-climatic influences. The accuracy and precision of climatic reconstruction can be improved significantly by expanding counts of minor taxa. Given this result, we re-examined the reconstructed climate using Osaka Bay palynological record reported in Kitaba et al. (2013). This new method did not significantly alter the overall variation in the reconstructed climate, and thus we conclude that the reconstruction was generally reliable. However, some intervals were strongly affected by depositional environmental change. In these, a climate signal can be extracted by excluding the patterns that arise from coastal sedimentation.

Stable isotope chemistry of fossil bone as a new paleoclimate indicator

NASA Astrophysics Data System (ADS)

Kohn, Matthew J.; Law, J. Mclver

2006-02-01

During fossilization, bone is thought to recrystallize and alter chemically on timescales of kyr to a few tens of kyr, i.e., similar to the timescale for formation of soils. Therefore, C- and O-isotope compositions of bone apatite should correlate with trends in soil water composition and aridity, and serve as paleoclimate indicators. This hypothesis was tested by analyzing C- and O-isotope compositions of the CO 3 component of fossil bone apatite from mid-Oligocene through late Pleistocene units in Oregon and western Idaho, including the John Day (19.4-30.0 Ma), Mascall (15.2-15.8 Ma), and Rattlesnake (7.2-7.8 Ma) Formations, whose paleosol sequences have been studied in detail, and the Juntura (10-11 Ma), Hagerman (3.2 Ma), and Fossil Lake (<23-650 ka) fossil localities. Tooth enamel δ18O values provide a baseline of meteoric water compositions. Stable isotope compositions of bone CO 3 do change in response to broad climatic trends, but show poor correlation with compositions of corresponding paleosol CO 3 at specific horizons. Instead, compositional deviations between bone and paleosol CO 3 correlate with compositional deviations with the next higher paleosol; this suggests that the timescale for fossilization exceeds one paleosol cycle. Based on stratigraphic evidence and simple alteration models, fossilization timescales are estimated at 20-50 kyr, indicating that bone CO 3 will prove most useful for sequences spanning >100 kyr. C-isotopes show negative and strong positive deviations during wet and dry climates respectively, and short-term trends correspond well with changes in aridity within the Mascall and Rattlesnake Formations, as inferred from paleosols. A proposed correction to δ18O values based on δ13C anomalies implies a small, ˜1.5‰ increase in meteoric water δ18O during the late Oligocene global warming event, consistent with a minimum temperature increase of ˜4 °C. A strong inferred decrease in δ18O of 4-5‰ after 7 Ma closely parallels

Late Pliocene Depositional History and Paleoclimate Reconstructions of the Southwest Pacific

NASA Astrophysics Data System (ADS)

Royce, B.; Patterson, M. O.; Pietras, J.

2017-12-01

Drift deposits off the eastern margin of New Zealand are important archives for the paleoclimate and paleoceanographic history of the southwest Pacific. Ocean Drilling Program (ODP) Site 1123 is located on the North Chatham rise drift just North of the westerly wind driven Subtropical Front (STF) and provides a record of near continuous sediment deposition since the Miocene along the southwest Pacific deep western boundary current (DWBC). While the Miocene and Late Pleistocene portion of this record have been well studied, the Late Pliocene record is less well developed. Southern Ocean geological records demonstrate that Late Pliocene cooling is the transient time bracketing the warmer than present Early Pliocene and bipolar glaciation at 2.7 Ma. A newly developed, robust, and astronomically tuned long-term record of benthic δ13C from ODP Site 1123 spanning the Early to Late Pliocene implies a reduction in Southern Ocean ventilation and lowering of preformed values from waters sourced along the Antarctic margin during the Late Pliocene. Thus, Late Pliocene Southern Hemisphere cooling and sea ice expansion may have drastically reduced outgassing and increased the burial of heat into the deep ocean. South Atlantic records off the west coast of Africa demonstrate an increase in the flux of iron to the open ocean during this time potentially enhancing surface ocean productivity and providing an additional cooling mechanism. Currently, atmospheric transport of dust to the Southern Ocean is dominated by persistent mid-latitude circumpolar westerly winds; this is particularly relevant for dust sourced from New Zealand. The Late Pliocene to Early Pleistocene uplift of the North Island axial ranges and South Island southern alps potentially provided a greater amount of not only sediment to the deep ocean, but also wind blow dust to the Pacific sector of the Southern Ocean. We will present a detailed high-resolution sedimentological study on the development of the Chatham

Climate-informed stochastic hydrological modeling: Incorporating decadal-scale variability using paleoclimate data

NASA Astrophysics Data System (ADS)

Henley, B. J.; Thyer, M. A.; Kuczera, G. A.

2012-12-01

A hierarchical framework for incorporating modes of climate variability into stochastic simulations of hydrological data is developed, termed the climate-informed multi-time scale stochastic (CIMSS) framework. To characterize long-term variability for the first level of the hierarchy, paleoclimate and instrumental data describing the Interdecadal Pacific Oscillation (IPO) and the Pacific Decadal Oscillation (PDO) are analyzed. A new paleo IPO-PDO time series dating back 440 yrs is produced, combining seven IPO-PDO paleo sources using an objective smoothing procedure to fit low-pass filters to individual records. The paleo data analysis indicates that wet/dry IPO-PDO states have a broad range of run-lengths, with 90% between 3 and 33 yr and a mean of 15 yr. Model selection techniques were used to determine a suitable stochastic model to simulate these run-lengths. The Markov chain model, previously used to simulate oscillating wet/dry climate states, was found to underestimate the probability of wet/dry periods >5 yr, and was rejected in favor of a gamma distribution. For the second level of the hierarchy, a seasonal rainfall model is conditioned on the simulated IPO-PDO state. Application to two high-quality rainfall sites close to water supply reservoirs found that mean seasonal rainfall in the IPO-PDO dry state was 15%-28% lower than the wet state. The model was able to replicate observed statistics such as seasonal and multi-year accumulated rainfall distributions and interannual autocorrelations for the case study sites. In comparison, an annual lag-one autoregressive AR(1) model was unable to adequately capture the observed rainfall distribution within separate IPO-PDO states. Furthermore, analysis of the impact of the CIMSS framework on drought risk analysis found that short-term drought risks conditional on IPO/PDO state were considerably higher than the traditional AR(1) model.hort-term conditional water supply drought risks for the CIMSS and AR(1) models

Genetic and archaeological perspectives on the initial modern human colonization of southern Asia

PubMed Central

Mellars, Paul; Gori, Kevin C.; Carr, Martin; Soares, Pedro A.; Richards, Martin B.

2013-01-01

It has been argued recently that the initial dispersal of anatomically modern humans from Africa to southern Asia occurred before the volcanic “supereruption” of the Mount Toba volcano (Sumatra) at ∼74,000 y before present (B.P.)—possibly as early as 120,000 y B.P. We show here that this “pre-Toba” dispersal model is in serious conflict with both the most recent genetic evidence from both Africa and Asia and the archaeological evidence from South Asian sites. We present an alternative model based on a combination of genetic analyses and recent archaeological evidence from South Asia and Africa. These data support a coastally oriented dispersal of modern humans from eastern Africa to southern Asia ∼60–50 thousand years ago (ka). This was associated with distinctively African microlithic and “backed-segment” technologies analogous to the African “Howiesons Poort” and related technologies, together with a range of distinctively “modern” cultural and symbolic features (highly shaped bone tools, personal ornaments, abstract artistic motifs, microblade technology, etc.), similar to those that accompanied the replacement of “archaic” Neanderthal by anatomically modern human populations in other regions of western Eurasia at a broadly similar date. PMID:23754394

The birth of modern criminology and gendered constructions of homosexual criminal identity.

PubMed

Woods, Jordan Blair

2015-01-01

There is a dearth of engagement with LGBTQ populations, and sexual orientation and gender identity more broadly, in the field of criminology. This article analyzes the treatment of sexual orientation and gender identity at the birth of the discipline around the 1870 s. Through an analysis of Cesare Lombroso's writings, the article argues that a multifaceted stigma of deviance attached to homosexuality and gender nonconformity in early criminological theory. The article explains this multifaceted stigma in terms of broader political, social, cultural, and legal developments before and during the late nineteenth century that shaped modern Western conceptions of sexual orientation and gender identity.

Problems and Possibilities: The Public Library in the Borderline between Modernity and Late Modernity

ERIC Educational Resources Information Center

Rasmussen, Casper Hvenegaard; Jochumsen, Henrik

2007-01-01

The public library is a product of modernity that follows in the wake of industrialization, urbanization, and popular movements, while at the same time the public library itself supports the building up and development of the modern. This article will examine the arrival of modernity and the prerequisites for the rise of public libraries, as well…

Promoting free flow in the networks: Reimagining the body in early modern Suzhou.

PubMed

Scheid, Volker

2017-06-01

The history of Chinese medicine is still widely imagined in terms dictated by the discourse of modernity, that is as 'traditional' and 'Chinese.' And yet, so as to be intelligible to us moderns, it must simultaneously be framed through categories that make it comparable somehow to the 'West' and the 'modern' from which it is said to be essentially different. This is accomplished, for instance, by viewing Chinese medicine as fundamentally shaped by cosmological thinking, as focusing on process rather than matter, and as forever hampered by attachments to the past even when it tries to innovate. At the same time, it is described as pursuing its objectives in ways that make sense in 'our' terms, too, such as the goal of creating physiological homeostasis through methods of supplementation and drainage. In this paper, I seek to move beyond this kind of analysis through a two-pronged approach. First, by focusing on the concept of tong - a character that calls forth images of free flow, connectivity, relatedness and understanding - I foreground an important aspect of Chinese medical thinking and practice that has virtually been ignored by Western historians of medicine and science. Second, by exploring how the influential physician Ye Tianshi (1664-1746) employed tong to advance medical thinking and practice at a crucial moment of change in the history of Chinese medicine, I demonstrate that physicians in early modern China moved towards new understandings of the body readily intelligible by modern biomedical anatomy. I argue that this mode of analysis allows us to transcend the limitations inherent in the current historiography of Chinese medicine: because it allows for comparison to emerge from our subject matter rather than imposing our imaginaries onto it in advance.

Post-communism: postmodernity or modernity revisited?

PubMed

Ray, L

1997-12-01

Coinciding with the popularity of postmodern theory, the fall of communism appeared to offer further evidence of the exhaustion of modernity. Such analysis is grounded in a view that the Soviet system was the epitome of modernity. An alternative approach regards post-communism as opening new terrains of struggle for modernity. Thus Habermas and others suggest that post-communist societies are rejoining the trajectory of western modernity whose problems they now recapitulate. This alternative view implies that Soviet systems were something other than 'modern', although their nature is not always clearly defined. However, even if post-communist societies do encounter problems of modernity, they do so in new circumstances where modernist notions of social development have become problematic. This article argues that, contrary to those who regard modernization or postmodernization as irresistible trends, core post-communist societies are likely to develop along an alternative path to that of western modernity. This is tentatively described as 'neo-mercantilist'.

Impact of prehistoric cooking practices on paleoenvironmental proxies in shell midden constituents

NASA Astrophysics Data System (ADS)

Müller, Peter; Staudigel, Philip; Murray, Sean T.; Westphal, Hildegard; Swart, Peter K.

2016-04-01

Paleoenvironmental proxy records such as oxygen isotopes of calcareous skeletal structures like fish otoliths or mollusk shells provide highest-resolution information about environmental conditions experienced by the organism. Accumulations of such skeletal structures by ancient coastal populations in so called "shell midden" deposits provide us with sub-seasonally resolved paleoclimate records covering time spans up to several millennia. Given their high temporal resolution, these deposits are increasingly used for paleoclimate reconstructions and complement our understanding of ancient climate changes. However, gathered as comestibles, most of these skeletal remains were subject to prehistoric cooking methods prior to deposition. The associated alteration of the chemical proxy signatures as well as the subsequent error for paleoenvironmental reconstructions remained almost entirely neglected so far. Here, we present clumped isotope, conventional oxygen and carbon isotopes as well as element:Ca ratios measured in modern bivalve shells after exposing them to different prehistoric cooking methods. Our data show that most cooking methods considerably alter commonly used paleoclimate proxy systems which can lead to substantial misinterpretations of ancient climate conditions. Since the magnitude of chemical alteration is not distinguishable from natural temperature variability in most coastal settings, the alteration of shell midden constituents by prehistoric cooking remains likely unnoticed in most cases. Thus, depending on the cooking method, pre-depositional heating might have introduced considerable errors into previous paleoclimate studies. However, our data also show that clumped isotope thermometry represents a suitable diagnostic tool to detect such pre-depositional cooking events and also allows differentiating between the most commonly applied prehistoric cooking methods.

Shape-Based Virtual Screening with Volumetric Aligned Molecular Shapes

PubMed Central

Koes, David Ryan; Camacho, Carlos J.

2014-01-01

Shape-based virtual screening is an established and effective method for identifying small molecules that are similar in shape and function to a reference ligand. We describe a new method of shape-based virtual screening, volumetric aligned molecular shapes (VAMS). VAMS uses efficient data structures to encode and search molecular shapes. We demonstrate that VAMS is an effective method for shape-based virtual screening and that it can be successfully used as a pre-filter to accelerate more computationally demanding search algorithms. Unique to VAMS is a novel minimum/maximum shape constraint query for precisely specifying the desired molecular shape. Shape constraint searches in VAMS are particularly efficient and millions of shapes can be searched in a fraction of a second. We compare the performance of VAMS with two other shape-based virtual screening algorithms a benchmark of 102 protein targets consisting of more than 32 million molecular shapes and find that VAMS provides a competitive trade-off between run-time performance and virtual screening performance. PMID:25049193

Wideband dual frequency modified ellipse shaped patch antenna for WLAN/Wi-MAX/UWB application

NASA Astrophysics Data System (ADS)

Jain, P. K.; Jangid, K. G.; R. Sharma, B.; Saxena, V. K.; Bhatnagar, D.

2018-05-01

This paper communicates the design and performance of microstrip line fed modified ellipses shaped radiating patch with defected ground structure. Wide impedance bandwidth performance is achieved by applying a pentagonal slot and T slot structure in ground plane. By inserting two semi ellipses shaped ring in ground, we obtained axial ratio bandwidth approx 600 MHz. The proposed antenna is simulated by utilizing CST Microwave Studio simulator 2014. This antenna furnishes wide impedance bandwidth approx. 4.23 GHz, which has spread into two bands 2.45 GHz - 5.73 GHz and 7.22 GHz - 8.17 GHz with nearly flat gain in operating frequency range. This antenna may be proved as a practicable structure for modern wireless communication systems including Wi-MAX, WLAN and lower band of UWB.

Rodent burrows in late Pleistocene paleosols at Korean Palaeolithic sites and their implications for paleoclimate changes

NASA Astrophysics Data System (ADS)

Lim, H.; Park, S.; Lee, J.; Lee, Y.

2013-12-01

Rodent burrows are commonly found at many Paleolithic archaeological sites in Korea. They are nearly straight in horizontal view and gently inclined in lateral view. Burrow diameters are mostly 7 - 10cm, and burrow length may reach a few meters. Vertical penetration depths are generally about 1 m from the surface, and the thickness of the burrow-bearing layer is about 1-2 m. Although no remains (bones, teeth, claws, and coprolites) were found within burrows, they are interpreted to have been produced by rodent-like mammals (probably ground squirrels) based on the size and architecture. According to the previous study, the age of these burrows was constrained to be between ca. 40,000 and 25,000 yr BP by tephrochronology, radiocarbon and optically stimulated luminescence dating results (Lim et al., 2007). However, little is known about the reason why these burrows have disappeared after late Pleistocene time. For this question, two explanations can be considered: extinction or migration. Since same kinds of burrows are still found in the high-latitude regions, such as Mongolia and North America, the possibility of extinction can be ruled out. Therefore, migration seems to be the most likely explanation. Our results show that the destruction of habitat caused by climate change during this period is the main reason for the northward migration of burrowing animals. This study suggests that rodent burrows found in the late Pleistocene paleosols can provide useful information on paleoclimate and paleoenvironmental changes.

Assessing Controls on the Geometry and Dimensions of Modern Barrier Islands

NASA Astrophysics Data System (ADS)

Mulhern, J.; Johnson, C. L.; Martin, J. M.

2015-12-01

Barrier islands are highly ephemeral features, shaped by wave, tide, and storm energy. The processes that govern the size, shape, and motion of barrier islands are not well constrained, yet central to coastal dynamics. While the global distribution of barrier islands has been mapped and assessed, there is little consensus on the forces controlling barrier island formation, motion, or preservation. This study presents a new semi-global database of modern barrier islands to better understand their morphology and spatial distribution. We have mapped, in Google Earth, the subaerial extent of >350 barrier islands and spits, measuring spatial characteristic such as exposed area, perimeter, length, and width. These objects are cross-referenced with parameters that potentially control morphology, including tidal range, wave height, climate, distance from the continental shelf, proximity to fluvial output, and tectonic setting. This approach provides a more optimal framework to assess controls on coastal features, including barrier island morphology, and to investigate potential geometric scaling relationships. Preliminary analysis shows trends in the spatial characteristics of barrier islands. There is a strong linear relationship between the perimeter and length (y= -0.59 + 0.42x, R2=0.95). Linear trends also relate length to area when the data are separated by tidal range to wave height ratio. Assessment of barrier island shape supports the hypothesis of Hayes (1979) that barrier islands in wave-dominated settings are long and linear while those in mixed energy setting are more rounded. The barrier islands of the Texas Gulf of Mexico are larger than the global average for the database, with distinctly longer length values (41.16 km vs. 15.77 km respectively) and larger areas (103.81 km2 vs. 42.14 km2 respectively). Initial assessment shows that tidal range and wave height are primary controls barrier island dimensions. Future work will consider climate, latitude, fluvial

Novel Catalysis by Gold: A Modern Alchemy

NASA Astrophysics Data System (ADS)

Haruta, Masatake

Gold has long been neglected as a catalyst because of its chemical inertness. However, when gold is deposited as nanoparticles on carbon and polymer materials as well as on base metal oxides and hydroxides, it exhibits unique catalytic properties for many reactions such as CO oxidation at a temperature as low as 200 K, gas phase direct epoxidation of propylene, and aerobic oxidation of glucose to gluconic acid. The structure-catalytic activity correlations are discussed with emphasis on the contact structure, support selection, and the size control of gold particles. Gold clusters with diameters smaller than 2 nm are expected to exhibit novel properties in catalysis, optics, and electronics depending on the size (number of atoms), shape, and the electronic and chemical interaction with the support materials. The above achievements and attempts can be regarded as a modern alchemy that creates valuables by means of the noblest element with little practical use.

Major hydrological regime change along the semiarid western coast of South America during the early Holocene

NASA Astrophysics Data System (ADS)

Ortega, Cristina; Vargas, Gabriel; Rutllant, José A.; Jackson, Donald; Méndez, César

2012-11-01

Water availability in the semiarid western coast of Chile (30-32°S) is conditioned by high interannual precipitation variability, reflecting the transition between arid subtropical and moist mid-latitude climates in the Southeastern Pacific Ocean. A paleoclimate reconstruction based on the latest Pleistocene-Holocene geological record from the Quebrada Santa Julia archeological site in Chile (31°50'S) and on modern meteorological mechanisms producing alluvial episodes in this region indicates a major change in the rainfall regime shortly after 8600 cal yr BP. This, together with other paleoclimate proxies along the west coast of South America (34°-14°S), suggests La Niña-like conditions 13,000-8600 cal yr BP. Based on sedimentological and geomorphologic evidence, we hypothesized that the absence of heavy rainfall events in northern Chile and the new hydrological regime that prevailed ca. 8600-5700 cal yr BP in north-central Chile resulted from an increase in the large-scale westerly flow over central Chile, as expected in near-neutral ENSO conditions. This atmospheric circulation anomaly is compatible with an equatorward shift of the influence of the Southeast Pacific Subtropical Anticyclone relative to the early Holocene, prior to the onset of modern ENSO variability.

The evolution of the platyrrhine talus: A comparative analysis of the phenetic affinities of the Miocene platyrrhines with their modern relatives.

PubMed

Püschel, Thomas A; Gladman, Justin T; Bobe, René; Sellers, William I

2017-10-01

Platyrrhines are a diverse group of primates that presently occupy a broad range of tropical-equatorial environments in the Americas. However, most of the fossil platyrrhine species of the early Miocene have been found at middle and high latitudes. Although the fossil record of New World monkeys has improved considerably over the past several years, it is still difficult to trace the origin of major modern clades. One of the most commonly preserved anatomical structures of early platyrrhines is the talus. This work provides an analysis of the phenetic affinities of extant platyrrhine tali and their Miocene counterparts through geometric morphometrics and a series of phylogenetic comparative analyses. Geometric morphometrics was used to quantify talar shape affinities, while locomotor mode percentages (LMPs) were used to test if talar shape is associated with locomotion. Comparative analyses were used to test if there was convergence in talar morphology, as well as different models that could explain the evolution of talar shape and size in platyrrhines. Body mass predictions for the fossil sample were also computed using the available articular surfaces. The results showed that most analyzed fossils exhibit a generalized morphology that is similar to some 'generalist' modern species. It was found that talar shape covaries with LMPs, thus allowing the inference of locomotion from talar morphology. The results further suggest that talar shape diversification can be explained by invoking a model of shifts in adaptive peak to three optima representing a phylogenetic hypothesis in which each platyrrhine family occupied a separate adaptive peak. The analyses indicate that platyrrhine talar centroid size diversification was characterized by an early differentiation related to a multidimensional niche model. Finally, the ancestral platyrrhine condition was reconstructed as a medium-sized, generalized, arboreal, quadruped. Copyright © 2017 The Authors. Published by

Multiproxy Holocene paleoclimate records from the southern Peruvian Andes - what new can we learn from the stable carbon isotope composition of high altitude organic matter deposits?

NASA Astrophysics Data System (ADS)

Skrzypek, Grzegorz; Engel, Zbyněk

2015-04-01

Interpretation of the Central Andean paleoclimate over the last millennia still represents a research challenge demanding deeper studies [1,2]. Several high-resolution paleoclimate proxies for the last 10,000 years have been developed for the northern hemisphere. However, similar proxies are very limited for South America, particularly for high altitudes where, for example, tree-ring chronologies are not available and instrumental records are very limited. Consequently, our knowledge of high altitude climate changes in arid regions of the Peruvian Andes mainly relies on ice-core and lake deposit studies. In our study, we used a new alternative proxy for interpretation of palaeoclimate conditions based on a peat core taken from the Carhuasanta Valley at the foot of Nevado Mismi in the southern Peruvian Andes (15° 30'S, 71° 43'W, 4809m a.s.l.). The stable carbon isotope composition (δ13C) of Distichia peat reflects mainly the relative variation of the mean air temperature during subsequent growing seasons [3], and allows reconstructions of palaeotemperature changes. In contrast, peat organic carbon concentration (C % wt) records mainly wetness in the valley, directly corresponding to the changes in runoff in the upper part of the catchment. The most prominent climate changes recorded in the peat over last 4ka occurred between 3040 and 2750 cal. yrs BP. The initial warming turned to a very rapid cooling to temperatures at least 2° C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP, when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes that match the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years, when

Genomic analyses of modern dog breeds.

PubMed

Parker, Heidi G

2012-02-01

A rose may be a rose by any other name, but when you call a dog a poodle it becomes a very different animal than if you call it a bulldog. Both the poodle and the bulldog are examples of dog breeds of which there are >400 recognized worldwide. Breed creation has played a significant role in shaping the modern dog from the length of his leg to the cadence of his bark. The selection and line-breeding required to maintain a breed has also reshaped the genome of the dog, resulting in a unique genetic pattern for each breed. The breed-based population structure combined with extensive morphologic variation and shared human environments have made the dog a popular model for mapping both simple and complex traits and diseases. In order to obtain the most benefit from the dog as a genetic system, it is necessary to understand the effect structured breeding has had on the genome of the species. That is best achieved by looking at genomic analyses of the breeds, their histories, and their relationships to each other.

Modern Aspects of Liquid Metal Engineering

NASA Astrophysics Data System (ADS)

Czerwinski, Frank

2017-02-01

Liquid metal engineering (LME) refers to a variety of physical and/or chemical treatments of molten metals aimed at influencing their solidification characteristics. Although the fundamentals have been known for decades, only recent progress in understanding solidification mechanisms has renewed an interest in opportunities this technique creates for an improvement of castings. This review covers conventional and novel concepts of LME with their application to modern manufacturing techniques based not only on liquid but also on semisolid routes. The role of external forces applied to the melt combined with grain nucleation control is explained along with laboratory- and commercial-scale equipment designed for implementation of various concepts exploring mechanical, electromagnetic, and ultrasound principles. An influence of melt treatments on quality of the final product is considered through distinguishing between internal integrity of net shape components and the alloy microstructure. Recent global developments indicate that exploring the synergy of melt chemistry and physical treatments achieved through LME allows creating the optimum conditions for nucleation and growth during solidification, positively affecting quality of castings.

Stable isotope study of fluid inclusions in fluorite from Idaho: implications for continental climates during the Eocene

USGS Publications Warehouse

Seal, R.R.; Rye, R.O.

1993-01-01

Isotopic studies of fluid inclusions from meteoric water-dominated epithermal ore deposits offer a unique opportunity to study paleoclimates because the fluids can provide direct samples of ancient waters. Fluorite-hosted fluid inclusions from the Eocene (51-50 Ma) epithermal deposits of the Bayhorse mining district, have low salinities and low to moderate homogenization temperatures indicating meteoric origins for the fluids. Oxygen and hydrogen isotope data on inclusion fluids are almost identical to those of modern meteoric waters in the area. The equivalence of the isotope composition of the Eocene inclusion fluids and modern meteoric waters indicates that the Eocene climatic conditions were similar to those today. -from Authors

Consuming sex: the association between modern goods, lifestyles and sexual behaviour among youth in Madagascar.

PubMed

Stoebenau, Kirsten; Nair, Rama C; Rambeloson, Valérie; Rakotoarison, Paul Ghislain; Razafintsalama, Violette; Labonté, Ronald

2013-03-19

goods, or modern lifestyles, such processes did not single-handedly explain risky sexual behaviour among youth; these behaviours were also shaped by culture and conditions of economic uncertainty. These determinants must all be accounted for when developing interventions to reduce risky transactional sex and vulnerability to HIV.

Paleoclimate records at high latitude in Arctic during the Paleogene

NASA Astrophysics Data System (ADS)

Salpin, Marie; Schnyder, Johann; Baudin, François; Suan, Guillaume; Labrousse, Loïc; Popescu, Speranta; Suc, Jean-Pierre

2015-04-01

Paleoclimate records at high latitude in Arctic during the Paleogene SALPIN Marie1,2, SCHNYDER Johann1,2, BAUDIN François1,2, SUAN Guillaume3, LABROUSSE Loïc1,2, POPESCU Speranta4, SUC Jean-Pierre1,4 1: Sorbonne Universités, UPMC Univ Paris 06, UMR 7193, Institut des Sciences de la Terre Paris (iSTeP), F 75005, Paris, France 2: CNRS, UMR 7193, Institut des Sciences de la Terre Paris (iSTeP), F 75005 Paris, France 3: UCB Lyon 1, UMR 5276, LGLTPE, 69622 Villeurbanne Cedex, France 4: GEOBIOSTRATDATA.CONSULTING, 385 Route du Mas Rillier 69140 Rillieux la Pape, France The Paleogene is a period of important variations of the Earth climate system either in warming or cooling. The climatic optima of the Paleogene have been recognized both in continental and marine environment. This study focus on high latitudes of the northern hemisphere, in the Arctic Basin. The basin has had an influence on the Cenozoic global climate change according to its polar position. Is there a specific behaviour of the Arctic Basin with respect to global climatic stimuli? Are there possible mechanisms of coupling/decoupling of its dynamics with respect to the global ocean? To answer these questions a unique collection of sedimentary series of Paleogene age interval has been assembled from the Laurentian margin in Northern Yukon (Canada) and from the Siberian margin (New Siberian Islands). Selected continental successions of Paleocene-Eocene age were used to study the response of the Arctic system to known global events, e.g. the climatic optima of the Paleogene (the so-called PETM, ETM2 or the Azolla events). Two sections of Paleocene-Eocene age were sampled near the Mackenzie delta, the so-called Coal Mine (CoMi) and Caribou Hills (CaH) sections. The aim of the study is to precise the climatic fluctuations and to characterise the source rock potential of the basin, eventually linked to the warming events. This study is based on data of multi-proxy analyses: mineralogy on bulk and clay

Volcanic degassing and secondary hydration of volcanic ash and scoria: Implications for paleoaltimetry and paleoclimate studies

NASA Astrophysics Data System (ADS)

Seligman, A. N.; Bindeman, I. N.

2013-12-01

The use of δD of ash as a reliable recorder of δD (and δ18O) values of paleoprecipitation in paleoclimate and paleoaltimetry research still requires experimental verification and testing. It is currently assumed that ash is deposited with a water content of no significance, and that within a few thousand years it becomes sufficiently (up to 4 wt.% H2O) hydrated, although the rate of hydration and whether or not the initial isotopic signature is held, are not well understood. We report analyses of δD and H2O of distal ash from recent eruptions (1980 Mount St. Helens, 1992 Mt. Spurr, and 1974 Volcán de Fuego) that were collected syneruption, in addition to scoria ranging in age from ~50 to 7300 years old from Klyuchevskoy volcano (Kamchatka, Russia), using the TC/EA - MAT 253 continuous flow system. Natural variability of studied samples in wt.% H2O (δD in ‰), with errors represented as 1 s.d. for the average, for recent ash eruptions, range from 0.1 × 0.07 (-102 × 4.7) for Volcán de Fuego up to 0.7 × 0.10 (-104 × 3.5) for Mount St. Helens. Ash from the Mt. Spurr eruption averaged 0.4 × 0.04 (-109 × 4.0), and we plan to also analyze ash from Mt. Pinatubo. The δD values are consistent with a magmatic degassing trend, where the last remaining water is depleted in deuterium, suggesting ash may be deposited with up to 0.7 wt.% H2O as primary magmatic water. Klyuchevskoy scoria (basaltic andesite) shows a general trend of increasing wt.% H2O with increasing age: the youngest samples (<2.0 ka) have ~0.2 wt.% water (-99 to -109 ‰), which is likely primary magmatic, while the older samples (4.7-7.3 ka) generally have a higher water concentration (~0.3-0.5 wt.%); likely local meteoric water based on δD values that are lower than degassed magmatic δD values and higher water content. The samples between ~2.3 and 3.6 ka (0.1 to 0.4 wt.% water) have variable water concentrations due to variations in porosity and therefore surface area between the different

Onwards and upwards in the Caucasus - A multidisciplinary approach to understanding the lifeways of the earliest modern humans in Armenia

NASA Astrophysics Data System (ADS)

Kandel, Andrew; Gasparyan, Boris; Bruch, Angela; Deckers, Katleen; Nahapetyan, Samvel; Weissbrod, Lior

2013-04-01

The Armenian Highlands have functioned as a gateway with regards to the peopling of the Southern Caucasus. Most importantly, changes in climate have long controlled access to this remote and often inhospitable mountainous region. Here we present the results of the multidisciplinary study of Aghitu-3 Cave which brings together researchers from the fields of archaeology, geology and geomorphology, zooarchaeology, paleobotany and paleoclimate. By integrating these areas of study, we have reconstructed the lifeways of the earliest behaviorally (and presumably anatomically) modern humans who settled Southern Armenia about 35,000 (cal BP) years ago and placed this occupational sequence within a framework of environmental change. These first Upper Paleolithic inhabitants of Armenia made temporary use of this basalt cave located along the Vorotan River corridor at an altitude of 1601 m during seasonal forays into the highlands. The infrequent use of this site as a hunting camp comes to an end at about 31,000 cal BP. The next package of sediment shows little evidence of human occupation, although fauna seem to flourish during the time between 31-29,000 cal BP. Following this phase of depopulation, the intensity of occupation increases substantially after 29,000 cal BP. Human presence is amply documented in the numerous stone artifacts, faunal remains and fireplaces that cover the site. These changes in population movement are echoed in the sequence of sediments preserved in the cave and can be correlated with the fluctuating climatic conditions associated with the late Pleistocene.

Depot Maintenance Modernization

DTIC Science & Technology

1988-02-01

process. However, this mobilization-planning process has not been implemented in the shipyards. Instead, NAVSEA has announcedl that " National economic...illustrate the type of modernization planning that occurs at the ALCs, we draw upon Oklahoma City’s Technology Enhancement and Modernization of Plant ... National Product - he concluded that the inflation-adjusted rate of return in the private sector was about 10 percent in 1965 (12 percent nominal rate

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

Book review: Mapping gendered routes and spaces in the early modern world

USGS Publications Warehouse

Varanka, Dalia E.

2016-01-01

This book encapsulates and extends many seminal ideas presented at the eighth “Attending to Early Modern Women” conference held at the University of Wisconsin–Milwaukee in June 2012. Merry Wiesner-Hanks has done a masterful job editing these papers within a central theme of the interaction of spatial domains with gender-based phenomena. The fifteen chapters of this book are organized into four sections: “Framework,” discussing theoretical concepts; “Embodied Environments,” focusing on physicality; “Communities and Networks” of social patterns; and “Exchanges” across geographic space. Together, a global society shaped by gender and sexuality and intersected by race and class emerges.

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.

Beam shaping to provide round and square-shaped beams in optical systems of high-power lasers

NASA Astrophysics Data System (ADS)

Laskin, Alexander; Laskin, Vadim

2016-05-01

Optical systems of modern high-power lasers require control of irradiance distribution: round or square-shaped flat-top or super-Gaussian irradiance profiles are optimum for amplification in MOPA lasers and for thermal load management while pumping of crystals of solid-state ultra-short pulse lasers to control heat and minimize its impact on the laser power and beam quality while maximizing overall laser efficiency, variable profiles are also important in irradiating of photocathode of Free Electron lasers (FEL). It is suggested to solve the task of irradiance re-distribution using field mapping refractive beam shapers like piShaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to flat-top one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design provides capability to work with ultra-short pulse lasers having broad spectrum. Using the same piShaper device it is possible to realize beams with flat-top, inverse Gauss or super Gauss irradiance distribution by simple variation of input beam diameter, and the beam shape can be round or square with soft edges. This paper will describe some design basics of refractive beam shapers of the field mapping type and optical layouts of their applying in optical systems of high-power lasers. Examples of real implementations and experimental results will be presented as well.

A lacustrine record from Lop Nur, Xinjiang, China: Implications for paleoclimate change during Late Pleistocene

USGS Publications Warehouse

Chao, L.; Zicheng, P.; Dong, Y.; Weiguo, L.; Zhaofeng, Z.; Jianfeng, H.; Chenlin, C.

2009-01-01

Climate variability during the Late Pleistocene is studied from the proxies in core CK-2 drilled from the Luobei Depression (91??03???E, 40??47???N), Lop Nur in the eastern Tarim Basin, Xinjiang, China. Geophysical and geochemical properties, including magnetic susceptibility, granularity, chroma, carbonate content, loss on ignition and trace elements, have been determined to reconstruct the environmental evolution of the area during 32-9 ka BP. The chronology is established by uranium-thorium disequilibrium dating techniques. Our data suggest four paleoclimate stages, indicating glacial variations between cold-humid and warm-arid environments. A period of extreme humidity occurred during 31,900-19,200 yr BP is attributed the last glacial maximum (LGM). The period was followed by a warm-arid episode during 19,200-13,500 yr BP. Then a cold-humid interval during 13,500-12,700 yr BP may correspond to another cooling phases at high latitudes of the Northern Hemisphere. The last stage from 12,700 to 9000 yr BP has a trend that the climate turned warm and arid. The Lop Nur region is characterized by particularly humid stadials and arid interstadials. The climate variability in Lop Nur was constrained by global climate change because it is correlated with Dansgaard-Oeschger and Heinrich events, which were observed at the northern high latitudes. The synchroneity of the palaeoclimatic events suggested that cold air activity at the northern high latitudes was the most important factor that influenced the climate evolution in the Lop Nur region. A probable mechanism that involves the migration of westerly winds is proposed to interpret this synchroneity. ?? 2008 Elsevier Ltd.

Documenting Modern Mexican Architectural Heritage for Posterity: Barragan's Casa Cristo, in Guadalajara, Mexico

NASA Astrophysics Data System (ADS)

Mezzino, D.; Pei, W.; Santana Quintero, M.; Reyes Rodriguez, R.

2015-08-01

This contribution describes the results of an International workshop on documentation of historic and cultural heritage developed jointly between Universidad de Guadalajara's Centro Universitario de Arte, Arquitectura y Diseño (CUAAD) and Carleton University's Architectural Conservation and Sustainability Program. The objective of the workshop was to create a learning environment for emerging heritage professionals through the use of advanced recording techniques for the documentation of modern architectural heritage in Guadalajara, Mexico. The selected site was Casa Cristo, one of the several architectural projects by Luis Barragán in Guadalajara. The house was built between 1927 and 1929 for Gustavo R. Cristo, mayor of the city. The style of the building reflects the European influences derived from the architect's travel experience, as well as the close connection with local craftsmanship. All of these make the house an outstanding example of modern regional architecture. A systematic documentation strategy was developed for the site, using different survey equipment and techniques to capture the shape, colour, spatial configuration, and current conditions of Casa Cristo for its eventual rehabilitation and conservation.

Sediment Transport Variability in Global Rivers: Implications for the Interpretation of Paleoclimate Signals

NASA Astrophysics Data System (ADS)

Syvitski, J. P.; Hutton, E. W.

2001-12-01

A new numerical approach (HydroTrend, v.2) allows the daily flux of sediment to be estimated for any river, whether gauged or not. The model can be driven by actual climate measurements (precipitation, temperature) or with statistical estimates of climate (modeled climate, remotely-sensed climate). In both cases, the character (e.g. soil depth, relief, vegetation index) of the drainage terrain is needed to complete the model domain. The HydroTrend approach allows us to examine the effects of climate on the supply of sediment to continental margins, and the nature of supply variability. A new relationship is defined as: $Qs = f (Psi) Qs-bar (Q/Q-bar)c+-σ where Qs-bar is the long-term sediment load, Q-bar is the long-term discharge, c and sigma are mean and standard deviation of the inter-annual variability of the rating coefficient, and Psi captures the measurement errors associated with Q and Qs, and the annual transients, affecting the supply of sediment including sediment and water source, and river (flood wave) dynamics. F = F(Psi, s). Smaller-discharge rivers have larger values of s, and s asymptotes to a small but consistent value for larger-discharge rivers. The coefficient c is directly proportional to the long-term suspended load (Qs-bar) and basin relief (R), and inversely proportional to mean annual temperature (T). sigma is directly proportional to the mean annual discharge. The long-term sediment load is given by: Qs-bar = a R1.5 A0.5 TT $ where a is a global constant, A is basin area; and TT is a function of mean annual temperature. This new approach provides estimates of sediment flux at the dynamic (daily) level and provides us a means to experiment on the sensitivity of marine sedimentary deposits in recording a paleoclimate signal. In addition the method provides us with spatial estimates for the flux of sediment to the coastal zone at the global scale.

A Record of Holocene Paleoclimate Evolution from Robertson Bay, Victoria Land, Antarctica

NASA Astrophysics Data System (ADS)

Riesselman, C. R.; Truax, O.; Wilson, G. S.; Parker, R. L.; Yoo, K. C.; Lee, J. I.; Levy, R. H.; Mckay, R. M.

2017-12-01

Regionally representative records of how Antarctica responded to the transition from the Last Glacial Maximum into the Holocene are an essential component of understanding the processes by which the Antarctic cryosphere responds to a changing climate. Here, we present a high-resolution record of Holocene Antarctic paleoclimate evolution from a previously unstudied section of the Victoria Land margin. In 2015 the Korea Polar Research Institute collected a 571 cm sediment core, GC57, from Robertson Bay, a protected embayment west of Cape Adare and adjacent to the outlet glaciers of the Transantarctic Mountains. Using diatom assemblages, bulk sediment geochemistry, and the magnetic properties of GC57, we aim to reconstruct the response of the East Antarctic Ice Sheet to warming associated with deglaciation and the Holocene climatic optima at the interface between the Ross Sea and the Southern Ocean. Our multiproxy approach allows us to study sea ice extent, seasonality, ocean stratification and circulation, and primary productivity from the mid-Holocene (7,400 14C year BP) to the present. A sea-ice associated diatom assemblage indicative of summer sea surface temperatures below 0˚C dominates the basal section of GC57. Although diatoms are well preserved, the unit is characterized by low wt% biogenic silica (average 9%) and a high concentration of magnetic minerals, indicating that biogenic production persisted despite substantial terrigenous input into the bay. A rapid transition at 4708 14C yr BP is identified by a steep increase in wt% BSi (average 13%), a decrease in magnetic minerals, and a subtle assemblage change towards sea-ice associated diatoms with slightly warmer temperature tolerances. The novel ramped pyrolosis 14C dating methodology allows us to date the carbon fixed concurrent with deposition and generate a robust age model for GC57 with an accuracy previously difficult to achieve given the uncertainties associated with dating bulk acid insoluble

Compact and broadband antenna based on a step-shaped metasurface.

PubMed

Li, Ximing; Yang, Jingjing; Feng, Yun; Yang, Meixia; Huang, Ming

2017-08-07

A metasurface (MS) is highly useful for improving the performance of patch antennae and reducing their size due to their inherent and unique electromagnetic properties. In this paper, a compact and broadband antenna based on a step-shaped metasurface (SMS) at an operating frequency of 4.3 GHz is presented, which is fed by a planar monopole and enabled by selecting an SMS with high selectivity. The SMS consists of an array of metallic step-shaped unit cells underneath the monopole, which provide footprint miniaturization and bandwidth expansion. Numerical results show that the SMS-based antenna with a maximum size of 0.42λ02 (where λ 0 is the operating wavelength in free space) exhibits a 22.3% impedance bandwidth (S11 < -10 dB) and a high gain of more than 7.15 dBi within the passband. Experimental results at microwave frequencies verify the performance of the proposed antenna, demonstrating substantial consistency with the simulation results. The compact and broadband antenna therefore predicts numerous potential applications within modern wireless communication systems.

Linear shaped charge

DOEpatents

Peterson, David; Stofleth, Jerome H.; Saul, Venner W.

2017-07-11

Linear shaped charges are described herein. In a general embodiment, the linear shaped charge has an explosive with an elongated arrowhead-shaped profile. The linear shaped charge also has and an elongated v-shaped liner that is inset into a recess of the explosive. Another linear shaped charge includes an explosive that is shaped as a star-shaped prism. Liners are inset into crevices of the explosive, where the explosive acts as a tamper.

A Reassessment of the Precision of Carbonate Clumped Isotope Measurements: Implications for Calibrations and Paleoclimate Reconstructions

NASA Astrophysics Data System (ADS)

Fernandez, Alvaro; Müller, Inigo A.; Rodríguez-Sanz, Laura; van Dijk, Joep; Looser, Nathan; Bernasconi, Stefano M.

2017-12-01

Carbonate clumped isotopes offer a potentially transformational tool to interpret Earth's history, but the proxy is still limited by poor interlaboratory reproducibility. Here, we focus on the uncertainties that result from the analysis of only a few replicate measurements to understand the extent to which unconstrained errors affect calibration relationships and paleoclimate reconstructions. We find that highly precise data can be routinely obtained with multiple replicate analyses, but this is not always done in many laboratories. For instance, using published estimates of external reproducibilities we find that typical clumped isotope measurements (three replicate analyses) have margins of error at the 95% confidence level (CL) that are too large for many applications. These errors, however, can be systematically reduced with more replicate measurements. Second, using a Monte Carlo-type simulation we demonstrate that the degree of disagreement on published calibration slopes is about what we should expect considering the precision of Δ47 data, the number of samples and replicate analyses, and the temperature range covered in published calibrations. Finally, we show that the way errors are typically reported in clumped isotope data can be problematic and lead to the impression that data are more precise than warranted. We recommend that uncertainties in Δ47 data should no longer be reported as the standard error of a few replicate measurements. Instead, uncertainties should be reported as margins of error at a specified confidence level (e.g., 68% or 95% CL). These error bars are a more realistic indication of the reliability of a measurement.

Shape coexistence and shape transition in light nuclei

NASA Astrophysics Data System (ADS)

Saxena, G.; Kumawat, M.; Singh, U. K.; Kaushik, M.; Jain, S. K.

2018-05-01

A systematic study has been performed to investigate the shape coexistence and shape transition for even-even nuclei between Z = 10-20 by employing Relativistic Mean-Filed plus BCS (RMF+BCS) approach. We calculate ground state properties viz. binding energy, deformation etc. for even-even nuclei to find the shape coexistence and shape transition. These results are found in agreement of recent experiments and consistent with other parameters of RMF and other theories.

Paleoclimate of the Neoglacial and Roman Warm Period Reconstructed from Oxygen Isotope Ratios of Limpet Shells (Patella vulgata), Northwest Scotland

NASA Astrophysics Data System (ADS)

Wang, T.; Surge, D. M.; Mithen, S.

2010-12-01

Paleoclimate reconstructions from different regions have reported abrupt climate change around 2800-2700 cal yr B.P. The timing of this abrupt climate change is close to the boundary between the Neoglacial (3300-2500 cal yr B.P.) and Roman Warm Period (2500-1600 cal yr B.P.). However, temporal and spatial variability observed in this climate change event raises controversies about the forcing factors driving it and why it has regional variability. Scotland lies in the North Atlantic Ocean, which responds sensitively to climate change. Therefore, even in the case of subtle climate change, the climate variability of Scotland should be able to capture such change. In this study, we expect that paleoclimate reconstructions of the Neoglacial and Roman Warm Period in Scotland will help improve our knowledge of abrupt climate change at 2800-2700 cal yr B.P. Archaeological shell deposits provide a rich source of climate proxy data preserved as oxygen isotope ratios in shell carbonate. Croig Cave on the Isle of Mull, Scotland, contains a nearly continuous accumulation of shells ranging from 800 BC-500 AD and possibly older. This range represents a broad chronology of human use from the late Bronze to Iron Ages and spans the Neoglacial through Roman Warm Period climate episodes. Here, we present seasonal temperature variability of the two climate episodes based on oxygen isotope ratios of ten limpet shells (Patella vulgata) from Croig Cave. Based on AMS dating (2 sigma calibration), the oldest shell was from 3480-3330 cal yr B.P. and the youngest shell was from 2060-1870 cal yr B.P. Our results indicated that estimated temperatures from the Neoglacial limpets average 6.44±0.56°C for coldest winters and 15.06±0.67°C for warmest summers. For the Roman Warm Period limpets, the average is 5.68±0.36°C for coldest winters and 14.14±0.81°C for warmest summers. We compared our estimated temperatures to the present sea surface temperature (SST) from 1961 to 1990 near our

Historical milestones and discoveries that shaped the toxicology sciences.

PubMed

Hayes, Antoinette N; Gilbert, Steven G

2009-01-01

Knowledge of the toxic and healing properties of plants, animals, and minerals has shaped civilization for millennia. The foundations of modern toxicology are built upon the significant milestones and discoveries of serendipity and crude experimentation. Throughout the ages, toxicological science has provided information that has shaped and guided society. This chapter examines the development of the discipline of toxicology and its influence on civilization by highlighting significant milestones and discoveries related to toxicology. The examples shed light on the beginnings of toxicology, as well as examine lessons learned and re-learned. This chapter also examines how toxicology and the toxicologist have interacted with other scientific and cultural disciplines, including religion, politics, and the government. Toxicology has evolved to a true scientific discipline with its own dedicated scientists, educational institutes, sub-disciplines, professional societies, and journals. It now stands as its own entity while traversing such fields as chemistry, physiology, pharmacology, and molecular biology. We invite you to join us on a path of discovery and to offer our suggestions as to what are the most significant milestones and discoveries in toxicology. Additional information is available on the history section of Toxipedia (www.toxipedia.org).

International travel as medical research: architecture and the modern hospital.

PubMed

Logan, Cameron; Willis, Julie

2010-01-01

The design and development of the modern hospital in Australia had a profound impact on medical practice and research at a variety of levels. Between the late 1920s and the 1950s hospital architects, administrators, and politicians travelled widely in order to review the latest international developments in the hospital field They were motivated by Australia's geographic isolation and a growing concern with how to govern the population at the level of physical health. While not 'medical research' in the conventional sense of the term, this travel was a powerful generator of medical thinking in Australia and has left a rich archival legacy. This paper draws on that archive to demonstrate the ways in which architectural research and international networks of hospital specialists profoundly shaped the provision of medical infrastructure in Australia.

Shaping Sexual Knowledge: A Cultural History of Sex Education in Twentieth Century Europe. Routledge Studies in the Social History of Medicine

ERIC Educational Resources Information Center

Sauerteig, Lutz, Ed.; Davidson, Roger, Ed.

2012-01-01

The history of sex education enables us to gain valuable insights into the cultural constructions of what different societies have defined as 'normal' sexuality and sexual health. Yet, the history of sex education has only recently attracted the full attention of historians of modern sexuality. "Shaping Sexual Knowledge: A Cultural History of…

"Modern Portuguese" and The Narration of Brazil

ERIC Educational Resources Information Center

Milleret, Margo

2016-01-01

"Modern Portuguese: A Project of the Modern Language Association" was a package of film strips, prerecorded tapes, an instructor's manual, and a textbook first published by Knopf in 1971. It followed the model established by "Modern Spanish" that was also a project of the Modern Language Association (MLA) published in 1960.The…

To Go Forward, We Must Look Back: The Importance of Evolutionary Psychology for Understanding Modern Politics.

PubMed

McDermott, Rose; Hatemi, Peter K

2018-01-01

As new waves of populism arise and cause disruption around the globe, there is both great interest in attempting to explain the origin of this dynamic as well as a need to ameliorate its potentially destructive impact. Perhaps the greatest signal of seismic change is the global dismantling of American institutional control of the postwar world following the election of Donald Trump in the United States. In the wake of such dramatic changes, it may seem odd to turn to evolutionary psychology which looks deeply into the past to try to understand current events, but, in fact, modern technology has dramatically changed the shape of political communication in just such a way as to make politics more personal once again, increasing the need to understand and interpret modern politics through an evolutionary lens. In fact, current modern political turmoils demonstrate how important evolutionary themes are and how critical they remain to understand how current forms of populism tape into older tribal sentiments and drives. Modern technology allows for a form of interpretative politics that no longer need to be mediated by political institutions or larger social structures, including enduring ones such as marriage. Indeed, in any ways, as we have technologically advanced, we have also regressed to more immediate, emotional, and personal forms of political communication. And it is only in understanding the nature of that personal political psychology that we can begin to grapple seriously with the challenges of today, including the consequences of global populism.

Investigating early modern Ottoman consumer culture in the light of Bursa probate inventories.

PubMed

Karababa, Eminegül

2012-01-01

This study investigates the development of early modern Ottoman consumer culture. In particular, the democratization of consumption, which is a significant indicator of the development of western consumer cultures, is examined in relation to Ottoman society. Sixteenth- and seventeenth-century probate inventories of the town of Bursa combined with literary and official sources are used in order to identify democratization of consumption and the macro conditions shaping this development. Findings demonstrate that commercialization, international trade, urbanization which created a fluid social structure, and the ability of the state to negotiate with guilds were possible contextual specificities which encouraged the democratization of consumption in the Bursa context.

Water Isotopes in the GISS GCM: History, Applications and Potential

NASA Astrophysics Data System (ADS)

Schmidt, G. A.; LeGrande, A. N.; Field, R. D.; Nusbaumer, J. M.

2017-12-01

Water isotopes have been incorporated in the GISS GCMs since the pioneering work of Jean Jouzel in the 1980s. Since 2005, this functionality has been maintained within the master branch of the development code and has been usable (and used) in all subsequent versions. This has allowed a wide variety of applications, across multiple time-scales and interests, to be tackled coherently. Water isotope tracers have been used to debug the atmospheric model code, tune parameterisations of moist processes, assess the isotopic fingerprints of multiple climate drivers, produce forward models for remotely sensed isotope products, and validate paleo-climate interpretations from the last millennium to the Eocene. We will present an overview of recent results involving isotope tracers, including improvements in models for the isotopic fractionation processes themselves, and demonstrate the potential for using these tracers and models more systematically in paleo-climate reconstructions and investigations of the modern hydrological cycle.

Identification of two new species of Meliolinites associated with Lauraceae leaves from the middle Miocene of Fujian, China.

PubMed

Wang, Zixi; Sun, Bainian; Sun, Fankai; Wang, Jidong; Dong, Junling; Sun, Mingxuan; Du, Baoxia

2017-01-01

Several studies have investigated both the paleoclimate and the well-preserved fossil remains from the middle Miocene found in China's Fujian Province. This study describes two new species of Meliolinites, including their fungal hyphae, reproductive structures, and spores. The distribution of modern Meliolaceae indicates that they live in warm, humid, subtropical to tropical climates. Moreover, the fossil leaves and the epiphyllous fungal remains, indicate the prevalence of a warm, humid, subtropical to tropical climate in this area during the middle Miocene. In addition, it was observed that the surrounding cells of the fungi found on the uninfected host leaves were normal, whereas the infected host leaves themselves were abnormally dim. These features are a reflection of self-protection, and it can, therefore, be inferred that the host leaves were alive when they were infected. The present study used fossil angiosperm leaves with cuticles obtained from the Fotan sediments from Fujian to investigate not only the taxonomy of the fossils but also to interpret the paleoclimate and paleoecology.

Shape memory polymers

DOEpatents

Wilson, Thomas S.; Bearinger, Jane P.

2017-08-29

New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

Shape memory polymers

DOEpatents

Wilson, Thomas S.; Bearinger, Jane P.

2015-06-09

New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

Femtosecond parabolic pulse shaping in normally dispersive optical fibers.

PubMed

Sukhoivanov, Igor A; Iakushev, Sergii O; Shulika, Oleksiy V; Díez, Antonio; Andrés, Miguel

2013-07-29

Formation of parabolic pulses at femtosecond time scale by means of passive nonlinear reshaping in normally dispersive optical fibers is analyzed. Two approaches are examined and compared: the parabolic waveform formation in transient propagation regime and parabolic waveform formation in the steady-state propagation regime. It is found that both approaches could produce parabolic pulses as short as few hundred femtoseconds applying commercially available fibers, specially designed all-normal dispersion photonic crystal fiber and modern femtosecond lasers for pumping. The ranges of parameters providing parabolic pulse formation at the femtosecond time scale are found depending on the initial pulse duration, chirp and energy. Applicability of different fibers for femtosecond pulse shaping is analyzed. Recommendation for shortest parabolic pulse formation is made based on the analysis presented.

Consuming sex: the association between modern goods, lifestyles and sexual behaviour among youth in Madagascar

PubMed Central

2013-01-01

between sexual behaviour and interest in modern goods, or modern lifestyles, such processes did not single-handedly explain risky sexual behaviour among youth; these behaviours were also shaped by culture and conditions of economic uncertainty. These determinants must all be accounted for when developing interventions to reduce risky transactional sex and vulnerability to HIV. PMID:23510104

Genomic Analyses of Modern Dog Breeds

PubMed Central

Parker, Heidi G.

2013-01-01

A rose may be a rose by any other name, but when you call a dog a poodle it becomes a very different animal than if you call it a bulldog. Both the poodle and the bulldog are examples of dog breeds of which there are >400 recognized world-wide. Breed creation has played a significant role in shaping the modern dog from the length of his leg to the cadence of his bark. The selection and line-breeding required to maintain a breed has also reshaped the genome of the dog resulting in a unique genetic pattern for each breed. The breed-based population structure combined with extensive morphologic variation and shared human environments have made the dog a popular model for mapping both simple and complex traits and diseases. In order to obtain the most benefit from the dog as a genetic system, it is necessary to understand the effect structured breeding has had on the genome of the species. That is best achieved by looking at genomic analyses of the breeds, their histories, and their relationships to each other. PMID:22231497

Paul Ehrenfest and the dilemmas of modernity.

PubMed

van Lunteren, Frans H; Hollestelle, Marijn J

2013-09-01

This essay considers the highly ambivalent attitude of the Austrian-Dutch physicist Paul Ehrenfest toward contemporary developments in both science and society. On the one hand, he was in the vanguard of the quantum and relativity revolutions, supported industrialization and economic planning based on mathematical models, and, in general, cherished technocratic ideals. The essay highlights several influences that shaped his attitude in these respects, from his ties with the Philips Physics Laboratory and his sojourns in the United States to the utopian visions of H. G. Wells. On the other hand, he was extremely worried about the harmful consequences of contemporary changes in science and society, such as specialization, the growing pace of city life, and the increasing dependence on modern technologies, be they material or mathematical. In this regard, he agreed with cultural critics such as Max Nordau, Henri Bergson, Ostwald Spengler, and Ludwig Klages. Rather than attempting to solve this paradox, the essay suggests that this kind of ambiguity characterized a great deal of innovative science in the period.

Teaching Modern Dance: A Conceptual Approach

ERIC Educational Resources Information Center

Enghauser, Rebecca Gose

2008-01-01

A conceptual approach to teaching modern dance can broaden the awareness and deepen the understanding of modern dance in the educational arena in general, and in dance education specifically. This article describes a unique program that dance teachers can use to introduce modern dance to novice dancers, as well as more experienced dancers,…

Functional aspects of metatarsal head shape in humans, apes, and Old World monkeys.

PubMed

Fernández, Peter J; Almécija, Sergio; Patel, Biren A; Orr, Caley M; Tocheri, Matthew W; Jungers, William L

2015-09-01

Modern human metatarsal heads are typically described as "dorsally domed," mediolaterally wide, and dorsally flat. Despite the apparent functional importance of these features in forefoot stability during bipedalism, the distinctiveness of this morphology has not been quantitatively evaluated within a broad comparative framework. In order to use these features to reconstruct fossil hominin locomotor behaviors with any confidence, their connection to human bipedalism should be validated through a comparative analysis of other primates with different locomotor behaviors and foot postures, including species with biomechanical demands potentially similar to those of bipedalism (e.g., terrestrial digitigrady). This study explores shape variation in the distal metatarsus among humans and other extant catarrhines using three-dimensional geometric morphometrics (3 DGM). Shape differences among species in metatarsal head morphology are well captured by the first two principal components of Procrustes shape coordinates, and these two components summarize most of the variance related to "dorsal doming" and "dorsal expansion." Multivariate statistical tests reveal significant differences among clades in overall shape, and humans are reliably distinguishable from other species by aspects of shape related to a greater degree of dorsal doming. Within quadrupeds, terrestrial species also trend toward more domed metatarsal heads, but not to the extent seen in humans. Certain aspects of distal metatarsus shape are likely related to habitual dorsiflexion of the metatarsophalangeal joints, but the total morphological pattern seen in humans is distinct. These comparative results indicate that this geometric morphometric approach is useful to characterize the complexity of metatarsal head morphology and will help clarify its relationship with function in fossil primates, including early hominins. Published by Elsevier Ltd.

Multiproxy biomarker, isotopic and pollen reconstructions of the middle to late Holocene paleoclimate of the Loess Plateau in centre China

NASA Astrophysics Data System (ADS)

Sun, H.; Seki, O.; Zhou, A.; Chen, F.; Schouten, S.; Toney, J. L.; Bendle, J.

2011-12-01

The Asian monsoon is a key component of the earth's climate system that directly affects the livelihood of 50 million people on the loess plateau of central China. At the far edge of monsoonal influence, this region is especially vulnerable to future changes in temperature and evaporation / precipitation. Therefore, paleoclimatic information on the natural sensitivity of the region to changes in monsoon driven aridity are crucial. Despite the need for multiproxy records of Holocene climate from this region, reconstructions are rare, because of the low resolution of loess deposits and the scarcity of other paleoclimate archives (e.g. natural lakes, speleothems). Here we present multiple proxy records from Tianchi lake, one of the few nature lakes on the loess plateau and central China. The chronology is well constrained by a high-resolution (20 AMS 14C dates) radiocarbon age-model, spanning the past 6200 years. Here we present pollen, Glycerol dibiphytanyl glycerol tetraethers (GDGTs), lake macrophyte and higher plant-wax biomarkers to reconstruct regional climate change during the middle to late Holocene. Evidence from pollen data suggest that deciduous trees decreased from 6200 cal yr BP and then more rapidly from 1000 yr BP. Modern and downcore molecular distribution patterns of n-alkanes and n-alkanoic acids, especially n-alkane Paq values, suggest increasing relative abundance of macrophytes over this time, which we interpret (based on lake morphology) as decreasing lake-level. Using the recent Sun et al (2011) regional calibration we derive mean annual GDGT based temperatures (MBT/CBT-MATs) with reasonable ranges. Our temperature reconstruction closely correlates on millennial to centennial timescales with the independent D/H measurements on C28 fatty acid methyl esters (C28 FAMEs), whose signal is assumed to derive primarily from terrestrial plant waxes and the δD values to reflect local changes in relative humidity. Comparisons of our independent GDGT

Social modernization and the increase in the divorce rate.

PubMed

Esser, H

1993-03-01

The author develops a micro-model of marital interactions that is used to analyze factors affecting the divorce rate in modern industrialized societies. The core of the model is the concept of production of marital gain and mutual control of this production. "The increase of divorce rates, then, is explained by a steady decrease of institutional and social embeddedness, which helps to solve this kind of an 'assurance game.' The shape of the individual risk is explained by the typical form of change of the 'production functions' of marriages within the first period of adaptation. The inconsistent results concerning womens' labor market participation in linear regression models are explained as a consequence of the (theoretical and statistical) 'interaction' of decreases in embeddedness and increases in external alternatives for women." Comments are included by Karl-Dieter Opp (pp. 278-82) and Ulrich Witt (pp. 283-5). excerpt

SHAPEMOL: Modelling molecular line emission in protoplanetary and planetary nebulae with SHAPE

NASA Astrophysics Data System (ADS)

Santander-García, M.; Bujarrabal, V.; Steffen, W.; Koning, N.

2014-04-01

Modern instrumentation in radioastronomy constitutes a valuable tool for studying the Universe: ALMA will reach unprecedented sensitivities and spatial resolution, while Herschel/HIFI has opened a new window for probing molecular warm gas (˜50-1000 K). On the other hand, the SHAPE software has emerged in the last few years as the standard tool for determining the morphology and velocity field of different kinds of gaseous emission nebulae via spatio-kinematical modelling. Standard SHAPE implements radiative transfer solving, but it is only available for atomic species and not for molecules. Being aware of the growing importance of the development of tools for easying the analyses of molecular data from new era observatories, we introduce the computer code shapemol, a plug-in for SHAPE v5.0 with which we intend to fill the so far empty molecular niche. Shapemol enables spatio-kinematic modeling with accurate non-LTE calculations of line excitation and radiative transfer in molecular species. This code has been succesfully tested in the study of the excitation conditions of the molecular envelope of the young planetary nebula NGC 7027 using data from Herschel/HIFI and IRAM 30m. Currently, it allows radiative transfer solving in the 12CO and 13CO J=1-0 to J=17-16 lines. Shapemol, used along SHAPE, allows to easily generate synthetic maps to test against interferometric observations, as well as synthetic line profiles to match single-dish observations.

Self-erecting shapes

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

Reading, Matthew W.

Technologies for making self-erecting structures are described herein. An exemplary self-erecting structure comprises a plurality of shape-memory members that connect two or more hub components. When forces are applied to the self-erecting structure, the shape-memory members can deform, and when the forces are removed the shape-memory members can return to their original pre-deformation shape, allowing the self-erecting structure to return to its own original shape under its own power. A shape of the self-erecting structure depends on a spatial orientation of the hub components, and a relative orientation of the shape-memory members, which in turn depends on an orientation ofmore » joining of the shape-memory members with the hub components.« less

Patterns on serpentine shapes elicit visual attention in marmosets (Callithrix jacchus).

PubMed

Wombolt, Jessica R; Caine, Nancy G

2016-09-01

Given the prevalence of threatening snakes in the evolutionary history, and modern-day environments of human and nonhuman primates, sensory, and perceptual abilities that allow for quick detection of, and appropriate response to snakes are likely to have evolved. Many studies have demonstrated that primates recognize snakes faster than other stimuli, and it is suggested that the unique serpentine shape is responsible for its quick detection. However, there are many nonthreatening serpentine shapes in the environment (e.g., vines) that are not threatening; therefore, other cues must be used to distinguish threatening from benign serpentine objects. In two experiments, we systematically evaluated how common marmosets (Callithrix jacchus) visually attend to specific snake-like features. In the first experiment, we examined if skin pattern is a cue that elicits increased visual inspection of serpentine shapes by measuring the amount of time the marmosets looked into a blind before, during, and after presentation of clay models with and without patterns. The marmosets spent the most time looking at the objects, both serpentine and triangle, that were etched with scales, suggesting that something may be uniquely salient about scales in evoking attention. In contrast, they showed relatively little interest in the unpatterned serpentine and control (a triangle) stimuli. In experiment 2, we replicated and extended the results of experiment 1 by adding additional stimulus conditions. We found that patterns on a serpentine shape generated more inspection than those same patterns on a triangle shape. We were unable to confirm that a scaled pattern is unique in its ability to elicit visual interest; the scaled models elicited similar looking times as line and star patterns. Our data provide a foundation for future research to examine how snakes are detected and identified by primates. Am. J. Primatol. 78:928-936, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals

The human dimensions of climate change: A micro-level assessment of views from the ecological modernization, political economy and human ecology perspectives.

PubMed

Adua, Lazarus; York, Richard; Schuelke-Leech, Beth-Anne

2016-03-01

Understanding the manifold human and physical dimensions of climate change has become an area of great interest to researchers in recent decades. Using a U.S. nationally-representative data set and drawing on the ecological modernization, political economy, and human ecology perspectives, this study examines the impacts of energy efficiency technologies, affluence, household demographics, and biophysical characteristics on residential CO2 emissions. Overall, the study provides mixed support for the ecological modernization perspective. While several findings are consistent with the theory's expectation that modern societies can harness technology to mitigate human impacts on the environment, others directly contradict it. Also, the theory's prediction of an inverted U-shaped relationship between affluence and environmental impacts is contradicted. The evidence is somewhat more supportive of the political economy and human ecology perspectives, with affluence, some indicators of technology, household demographics, and biophysical characteristics emerging as important drivers of residential CO2 emissions. Copyright © 2015 Elsevier Inc. All rights reserved.

An evaluation in a modern wind tunnel of the transonic adaptive wall adjustment strategy developed by NPL in the 1940's

NASA Technical Reports Server (NTRS)

Lewis, M. C.

1988-01-01

The first documented wind tunnel employing a flexible walled test section for the purpose of eliminating wall interference was constructed in England by the National Physical Laboratory (NPL) during the late 1930's. The tunnel was transonic and designed for two-dimensional testing. In an attempt to eliminate the top and bottom wall interference effects on the model NPL developed a strategy to adjust two flexible walls to streamlined shapes. This report covers an evaluation of the NPL wall adjustment strategy in a modern wind tunnel, e.g., the Transonic Self-Streamlining Wind Tunnel (TSWT) at the University of Southampton, England. The evaluation took the form of performance comparisons with other modern strategies which have been developed for use in, and proven in, the TSWT.

The interaction of neutral evolutionary processes with climatically-driven adaptive changes in the 3D shape of the human os coxae.

PubMed

Betti, Lia; von Cramon-Taubadel, Noreen; Manica, Andrea; Lycett, Stephen J

2014-08-01

Differences in the breadth of the pelvis among modern human populations and among extinct hominin species have often been interpreted in the light of thermoregulatory adaptation, whereby a larger pelvic girdle would help preserve body temperature in cold environments while a narrower pelvis would help dissipate heat in tropical climates. There is, however, a theoretical problem in interpreting a pattern of variation as evidence of selection without first accounting for the effects of neutral evolutionary processes (i.e., mutation, genetic drift and migration). Here, we analyse 3D configurations of 27 landmarks on the os coxae of 1494 modern human individuals representing 30 male and 23 female populations from five continents and a range of climatic conditions. We test for the effects of climate on the size and shape of the pelvic bone, while explicitly accounting for population history (i.e., geographically-mediated gene flow and genetic drift). We find that neutral processes account for a substantial proportion of shape variance in the human os coxae in both sexes. Beyond the neutral pattern due to population history, temperature is a significant predictor of shape and size variation in the os coxae, at least in males. The effect of climate on the shape of the pelvic bone, however, is comparatively limited, explaining only a small percentage of shape variation in males and females. In accordance with previous hypotheses, the size of the os coxae tends to increase with decreasing temperature, although the significance of the association is reduced when population history is taken into account. In conclusion, the shape and size of the human os coxae reflect both neutral evolutionary processes and climatically-driven adaptive changes. Neutral processes have a substantial effect on pelvic variation, suggesting such factors will need to be taken into account in future studies of human and fossil hominin coxal variation. Copyright © 2014 Elsevier Ltd. All rights

Mesozoic paleogeography and paleoclimates - A discussion of the diverse greenhouse and hothouse conditions of an alien world

NASA Astrophysics Data System (ADS)

Holz, Michael

2015-08-01

The Mesozoic was the time of the break-up of Pangaea, with profound consequences not only for the paleocontinental configuration, but also for paleoclimates and for the evolution of life. Cool greenhouse conditions alternated with warm greenhouse and even hothouse conditions, with global average temperatures around 6-9 °C warmer than the present ones. There are only sparse and controversial evidence for polar ice; meanwhile, extensive evaporitic and desertic deposits are well described. Global sea levels were mainly high, and the content of atmospheric O2 was varying between 15 and 25%. These conditions make the Mesozoic Earth an alien world compared to present-day conditions. Degassing from volcanism linked to the rifting process of Pangaea and methane emissions from reptilian biotas were climate-controlling factors because they enhanced atmospheric CO2 concentrations up to 16 times compared to present-day levels. The continental break-up modified paleopositions and shoreline configurations of the landmasses, generating huge epicontinental seas and altering profoundly the oceanic circulation. The Mesozoic was also a time of important impact events as probable triggers for "impact winters"; and for the Era at least nine huge (diameter > 20 km) impact structures are known. This paper presents an abridged but updated overview of the Mesozoic paleogeographic and paleoclimatic variations, characterizing each period and sub-period in terms of paleoclimatic state and main tectonic and climatic events, and provides a brief geologic, stratigraphic, paleoclimatic and taphonomic characterization of dinosaur occurrences as recorded in the Brazilian continental basins.

High-resolution paleoclimate records of Holocene hydroclimatic variability in the Eastern Colombian Andes from Lago de Tota

NASA Astrophysics Data System (ADS)

Ahmed, M. N.; Bird, B. W.; Escobar, J.; Polissar, P. J.

2017-12-01

The Northern Hemisphere (NH) South American Monsoon (SAM) is a significant source of precipitation for the North Andes (north of 0˚) and has major control over regional hydroclimate variability. Holocene-length histories of NH SAM variability are few compared to the Southern Hemisphere (SH), limiting understanding of how these systems are connected on orbital and shorter timescales. Here, we present multi-proxy lake-sediment-based paleoclimate and paleohydrologic reconstructions from Lago de Tota, Colombia, using sedimentological, geochemical and leaf-wax hydrogen isotopic indicators from radiometically dated cores. The results indicate periods of wet and dry climate phases during the past 9000 BP with an average Holocene sedimentation rate 33cm/kyr. An increase in total organic matter (TOM) content and finer grain-size distributions was observed from 8000 to 3200 BP, suggesting a period of high lake level. This was followed by lower TOM and coarser grain sizes, suggesting lower lake levels from 3200 BP to the present. Although Tota's lake level pattern is antiphased with other lake level reconstructions from the NH and SH Andes, it is consistent with hypothesized changes in atmospheric convection over the Andes during the Holocene and the way in which they would be modified by the so-called dry island effect in the Colombian Andes. This suggests that a common forcing mechanism can be invoked to explain differing millennial-scale Andean hydroclimate changes, namely atmospheric convection. Orbital and Pacific atmosphere-forcing are therefore likely to have played a significant role in driving pan-Andean hydroclimate variability based on their inter-hemispheric influence on Andean convection.

Mendel in the Modern Classroom

NASA Astrophysics Data System (ADS)

Smith, Mike U.; Gericke, Niklas M.

2015-01-01

Mendel is an icon in the history of genetics and part of our common culture and modern biology instruction. The aim of this paper is to summarize the place of Mendel in the modern biology classroom. In the present article we will identify key issues that make Mendel relevant in the classroom today. First, we recount some of the historical controversies that have relevance to modern curricular design, such as Fisher's (Ann Sci 1:115-137, 1936/2008) claim that Mendel's data were too good to be true. We also address questions about Mendel's status as the father of genetics as well as questions about the sequencing of Mendel's work in genetics instruction in relation to modern molecular genetics and evolution. Next, we present a systematic set of examples of research based approaches to the use of Mendel in the modern classroom along with criticisms of these designs and questions about the historical accuracy of the story of Mendel as presented in the typical classroom. Finally, we identify gaps in our understanding in need of further study and present a selected set of resources that, along with the references cited, should be valuable to science educators interested in further study of the story of Mendel.

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

Liquid metals as ultra-stretchable, soft, and shape reconfigurable conductors

NASA Astrophysics Data System (ADS)

Eaker, Collin B.; Dickey, Michael D.

2015-05-01

Conventional, rigid materials remain the key building blocks of most modern electronic devices, but they are limited in their ability to conform to curvilinear surfaces. It is possible to make electronic components that are flexible and in some cases stretchable by utilizing thin films, engineered geometries, or inherently soft and stretchable materials that maintain their function during deformation. Here, we describe the properties and applications of a micromoldable liquid metal that can form conductive components that are ultra-stretchable, soft, and shape-reconfigurable. This liquid metal is a gallium-based alloy with low viscosity and high conductivity. The metal develops spontaneously a thin, passivating oxide layer on the surface that allows the metal to be molded into non-spherical shapes, including films and wires, and patterned by direct-write techniques or microfluidic injection. Furthermore, unlike mercury, the liquid metal has low toxicity and negligible vapor pressure. This paper discusses the mechanical and electrical properties of the metal in the context of electronics, and discusses how the properties of the oxide layer have been exploited for new patterning techniques that enable soft, stretchable and reconfigurable devices.

Oxygen isotope ratios (18O/16O) of hemicellulose-derived sugar biomarkers in plants, soils and sediments as paleoclimate proxy I: Insight from a climate chamber experiment

NASA Astrophysics Data System (ADS)

Zech, Michael; Mayr, Christoph; Tuthorn, Mario; Leiber-Sauheitl, Katharina; Glaser, Bruno

2014-02-01

The oxygen isotopic composition of cellulose is a valuable proxy in paleoclimate research. However, its application to sedimentary archives is challenging due to extraction and purification of cellulose. Here we present compound-specific δ18O results of hemicellulose-derived sugar biomarkers determined using gas chromatography-pyrolysis-isotope ratio mass spectrometry, which is a method that overcomes the above-mentioned analytical challenges. The biomarkers were extracted from stem material of different plants (Eucalyptus globulus, Vicia faba and Brassica oleracea) grown in climate chamber experiments under different climatic conditions. The δ18O values of arabinose and xylose range from 31.4‰ to 45.9‰ and from 28.7‰ to 40.8‰, respectively, and correlate highly significantly with each other (R = 0.91, p < 0.001). Furthermore, δ18Ohemicellulose (mean of arabinose and xylose) correlate highly significantly with δ18Oleaf water (R = 0.66, p < 0.001) and significantly with modeled δ18Ocellulose (R = 0.42, p < 0.038), as well as with relative air humidity (R = -0.79, p < 0.001) and temperature (R = -0.66, p < 0.001). These findings confirm that the hemicellulose-derived sugar biomarkers, like cellulose, reflect the oxygen isotopic composition of plant source water altered by climatically controlled evapotranspirative 18O enrichment of leaf water. While relative air humidity controls most rigorously the evapotranspirative 18O enrichment, the direct temperature effect is less important. However, temperature can indirectly exert influence via plant physiological reactions, namely by influencing the transpiration rate which affects δ18Oleaf water due to the Péclet effect. In a companion paper (Tuthorn et al., this issue) we demonstrate the applicability of the hemicellulose-derived sugar biomarker δ18O method to soils and provide evidence from a climate transect study confirming that relative air humidity exerts the dominant control on evapotranspirative 18O

Model based paleoclimate interpretations of Holocene oxygen isotope records from the Pacific Northwest

NASA Astrophysics Data System (ADS)

Steinman, B. A.; Pompeani, D. P.; Abbott, M. B.; Ortiz, J. D.; Stansell, N.; Mihindukulasooriya, L. N.; Hillman, A. L.; Finkenbinder, M. S.

2015-12-01

Oxygen isotope measurements of authigenic carbonate from Cleland Lake (British Columbia), Paradise Lake (British Columbia), and Lime Lake (Washington) provide an ~9,000 year Holocene record of precipitation-evaporation balance variations in the Pacific Northwest. Both Cleland Lake and Paradise Lake are small, surficially closed-basin systems with no active inflows or outflows. Lime Lake is surficially open with a seasonally active overflow. We sampled the lake sediment cores at 1-60 mm intervals (~3-33 years per sample on average) and measured the isotopic composition of fine-grained, authigenic CaCO3 in each sample. Negative δ18O values, which indicate wetter conditions in closed-basin lakes, occur in Cleland Lake and Paradise Lake sediment during the mid-Holocene and are followed by more positive δ18O values, which suggest drier conditions, in the late Holocene. The δ18O record from Lime Lake, which principally reflects changes in the isotopic composition of precipitation, exhibits less variability than the closed-basin lake records and follows an increasing trend from the mid-Holocene to present. Power spectrum analysis of the Cleland Lake δ18O data from 1,000 yr BP to present demonstrates significant periodicities of ~6 and ~67 years that likely reflect the enhancement of El Niño Southern Oscillation (ENSO) variability in the late Holocene with an associated multidecadal (i.e., 50 to 70 yr) component of the Pacific Decadal Oscillation. Results from mid-Holocene (6,000 yr BP) climate model simulations conducted as part of the Paleoclimate Modeling Intercomparison Project Phase 3 (PMIP3) indicate that in much of western North America, the cold season was wetter, and the warm season (April-September) was considerably drier (relative to the late Holocene), leading to an overall drier climate in western North America but with enhanced hydroclimatic seasonality. This is consistent with inferences from the Cleland and Paradise Lake δ18O records, which lake

Sixth International Limnogeology Congress: abstract volume, Reno, Nevada, June 15-19, 2015

USGS Publications Warehouse

Rosen, Michael R.; Cohen, Andrew S.; Kirby, Matthew; Gierlowski-Kordesch, Elizabeth; Starratt, Scott W.; Valero Garcés, Blas L.; Varekamp, Johan

2015-01-01

The U.S. Geological Survey has sponsored each ILIC that has been held in the United States because of the importance of understanding paleoclimate and contaminant histories of lakes, two main themes of the Congress. This volume provides a permanent record of the wide variety of studies that are being conducted in modern lakes and ancient lake deposits worldwide, and it provides a stepping stone for any one desiring further discussion of the work that was presented at ILIC6.

Aerodynamic Shape Optimization Using Hybridized Differential Evolution

NASA Technical Reports Server (NTRS)

Madavan, Nateri K.

2003-01-01

An aerodynamic shape optimization method that uses an evolutionary algorithm known at Differential Evolution (DE) in conjunction with various hybridization strategies is described. DE is a simple and robust evolutionary strategy that has been proven effective in determining the global optimum for several difficult optimization problems. Various hybridization strategies for DE are explored, including the use of neural networks as well as traditional local search methods. A Navier-Stokes solver is used to evaluate the various intermediate designs and provide inputs to the hybrid DE optimizer. The method is implemented on distributed parallel computers so that new designs can be obtained within reasonable turnaround times. Results are presented for the inverse design of a turbine airfoil from a modern jet engine. (The final paper will include at least one other aerodynamic design application). The capability of the method to search large design spaces and obtain the optimal airfoils in an automatic fashion is demonstrated.

The role of Austrian physicians and Prof. Joseph Hyrtl (1810-1894) on modernization of Ottoman-Turkish medicine.

PubMed

Ortuğ, Gürsel; Yücel, Ferruh; Ay, Hakan

2003-12-01

Medical schools have a long history in Ottoman-Turkish medical education. At Ottoman medical schools (medreses), education has been given to students regularly. But because of social dogma and oppression of religion on the science of human anatomy they could not get a chance to improve for centuries. Traditionally, Ottoman-Turkish medical education was shaped under the influence of Galenos (129-200) and Avicenna (980-1037). These influences continued until the beginning of the 19th century. In this period, Avicenna's most famous medical book "Kanun-i fit-tip" was a main anatomy textbook in medical education of the eleventh century. Modernization of educational systems in the Ottoman Empire started during the reign of Sultan Selim the 3rd (1789-1807) and modern anatomy in Ottoman-Turkish Medicine has flourished following the Austrian physicians. Today's Department of Anatomy at Istanbul Medical School of the Istanbul University is a continuation of Galatasaray Medical School which was the first medical school achieving the western educational level.

Sound transmission in archaic and modern whales: anatomical adaptations for underwater hearing.

PubMed

Nummela, Sirpa; Thewissen, J G M; Bajpai, Sunil; Hussain, Taseer; Kumar, Kishor

2007-06-01

The whale ear, initially designed for hearing in air, became adapted for hearing underwater in less than ten million years of evolution. This study describes the evolution of underwater hearing in cetaceans, focusing on changes in sound transmission mechanisms. Measurements were made on 60 fossils of whole or partial skulls, isolated tympanics, middle ear ossicles, and mandibles from all six archaeocete families. Fossil data were compared with data on two families of modern mysticete whales and nine families of modern odontocete cetaceans, as well as five families of noncetacean mammals. Results show that the outer ear pinna and external auditory meatus were functionally replaced by the mandible and the mandibular fat pad, which posteriorly contacts the tympanic plate, the lateral wall of the bulla. Changes in the ear include thickening of the tympanic bulla medially, isolation of the tympanoperiotic complex by means of air sinuses, functional replacement of the tympanic membrane by a bony plate, and changes in ossicle shapes and orientation. Pakicetids, the earliest archaeocetes, had a land mammal ear for hearing in air, and used bone conduction underwater, aided by the heavy tympanic bulla. Remingtonocetids and protocetids were the first to display a genuine underwater ear where sound reached the inner ear through the mandibular fat pad, the tympanic plate, and the middle ear ossicles. Basilosaurids and dorudontids showed further aquatic adaptations of the ossicular chain and the acoustic isolation of the ear complex from the skull. The land mammal ear and the generalized modern whale ear are evolutionarily stable configurations, two ends of a process where the cetacean mandible might have been a keystone character. 2007 Wiley-Liss, Inc.

Modern Spectroscopy

ERIC Educational Resources Information Center

Barrow, Gordon M.

1970-01-01

Presents the basic ideas of modern spectroscopy. Both the angular momenta and wave-nature approaches to the determination of energy level patterns for atomic and molecular systems are discussed. The interpretation of spectra, based on atomic and molecular models, is considered. (LC)

African Cultural Traditions and Modernization: A Reaffirmation.

ERIC Educational Resources Information Center

Boateng, Felix A.

1978-01-01

The viability of African cultural traditions and their role in modernization and nation-building in Africa are examined. Social and political organization and formal education are discussed in relation to the process of modernization. Although Africa may utilize Western models of development, Westernization and modernization are not synonymous.…

24 CFR 901.15 - Indicator #2, modernization.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Indicator #2, modernization. 901.15... DEVELOPMENT PUBLIC HOUSING MANAGEMENT ASSESSMENT PROGRAM § 901.15 Indicator #2, modernization. This indicator is automatically excluded if a PHA does not have a modernization program. This indicator examines the...

Snails, stable iostopes, and southwestern desert paleoclimates

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

Sharpe, S.E.; Whelan, J.F.; Forester, R.M.

1995-09-01

Modern and fossil molluscs (snails) occur in many localities in and semi-arid regions throughout the desert southwest. Live terrestrial snails are found under rocks and in forest litter and aquatic taxa inhabit springs, seeps, and/or wetlands. Molluscs uptake local water during their growing season (spring and summer) and incorporate its delta 180 signature into their shells. Preliminary 180 analysis of modem shells from the southern Great Basin indicates that the shells probably reflect meteoric water 180 values during the growing season. This provides a way to estimate the delta 180 value of precipitation and, thereby, the source of the moisture-bearingmore » air masses. Significant 180 variability in shells analyzed include geographic location, elevation, taxonomy, and habitat (terrestrial, spring, or wetland). We found a rough inverse correlation with elevation in modem shells from the Spring Range in southern Nevada. The delta 180 values of modem and fossil shells are also very different; modem values in this location are much higher than those from nearby late Pleistocene-age molluscs suggesting that the Pleistocene summers were variously colder and wetter than today or less evaporative (more humid). Assuming shell material directly reflects the 180 of the growing-season environment, comparison of modem and fossil shell delta 180 values can potentially identify changes in air-mass moisture sources and can help to define seasonal precipitation change through time. Comprehension and quantification of community and isotopic variability in modem gastropods is required to create probabilistic valid transfer functions with fossil materials. Valid inferences about past environmental conditions can then be established with known confidence limits.« less

Subject-specific longitudinal shape analysis by coupling spatiotemporal shape modeling with medial analysis

NASA Astrophysics Data System (ADS)

Hong, Sungmin; Fishbaugh, James; Rezanejad, Morteza; Siddiqi, Kaleem; Johnson, Hans; Paulsen, Jane; Kim, Eun Young; Gerig, Guido

2017-02-01

Modeling subject-specific shape change is one of the most important challenges in longitudinal shape analysis of disease progression. Whereas anatomical change over time can be a function of normal aging, anatomy can also be impacted by disease related degeneration. Anatomical shape change may also be affected by structural changes from neighboring shapes, which may cause non-linear variations in pose. In this paper, we propose a framework to analyze disease related shape changes by coupling extrinsic modeling of the ambient anatomical space via spatiotemporal deformations with intrinsic shape properties from medial surface analysis. We compare intrinsic shape properties of a subject-specific shape trajectory to a normative 4D shape atlas representing normal aging to isolate shape changes related to disease. The spatiotemporal shape modeling establishes inter/intra subject anatomical correspondence, which in turn enables comparisons between subjects and the 4D shape atlas, and also quantitative analysis of disease related shape change. The medial surface analysis captures intrinsic shape properties related to local patterns of deformation. The proposed framework jointly models extrinsic longitudinal shape changes in the ambient anatomical space, as well as intrinsic shape properties to give localized measurements of degeneration. Six high risk subjects and six controls are randomly sampled from a Huntington's disease image database for qualitative and quantitative comparison.

Globalization, National Identity, and Citizenship Education: China's Search for Modernization and a Modern Chinese Citizenry

ERIC Educational Resources Information Center

Law, Wing-Wah

2013-01-01

Since the early 20th century, numerous scholars have proposed theories and models describing, interpreting, and suggesting the development paths countries have taken or should take. None of these, however, can fully explain China's efforts, mainly through education and citizenship education, to modernize itself and foster a modern citizenry since…

School Physical Education in the Transition from Solid Modernity to Liquid Modernity: The Brazilian Case

ERIC Educational Resources Information Center

Bracht, Valter; Gomes, Ivan Marcelo; de Almeida, Felipe Quintão

2015-01-01

This article discusses the implications of the contemporary transition from a solid modernity to a liquid modernity for school physical education, according to the metaphors adopted by the Polish sociologist and English resident Zygmunt Bauman. By leveraging Bauman's sociological theory, this article pursues two aims: (1) to examine how physical…

Modernity: a non-European conceptualization.

PubMed

Mouzelis, N

1999-03-01

In the light of insights drawn from historical sociology and Parsons' theory of differentiation/modernization, an attempt is made to conceptualize modernity in such a way as to avoid both eurocentrism and the total rejection of the concept by those who view it as an ideological means for the further advancement of western cultural imperialism.

Institutional Support | Grid Modernization | NREL

Science.gov Websites

the challenges posed by grid modernization. Photo of two people standing in front of a display showing results from a grid study. The demand for objective technical assistance and information on grid related to grid modernization and increasing deployment of distributed energy and renewable resources. As

Adaptations to local environments in modern human populations.

PubMed

Jeong, Choongwon; Di Rienzo, Anna

2014-12-01

After leaving sub-Saharan Africa around 50000-100000 years ago, anatomically modern humans have quickly occupied extremely diverse environments. Human populations were exposed to further environmental changes resulting from cultural innovations, such as the spread of farming, which gave rise to new selective pressures related to pathogen exposures and dietary shifts. In addition to changing the frequency of individual adaptive alleles, natural selection may also shape the overall genetic architecture of adaptive traits. Here, we review recent advances in understanding the genetic architecture of adaptive human phenotypes based on insights from the studies of lactase persistence, skin pigmentation and high-altitude adaptation. These adaptations evolved in parallel in multiple human populations, providing a chance to investigate independent realizations of the evolutionary process. We suggest that the outcome of adaptive evolution is often highly variable even under similar selective pressures. Finally, we highlight a growing need for detecting adaptations that did not follow the classical sweep model and for incorporating new sources of genetic evidence such as information from ancient DNA. Copyright © 2014 Elsevier Ltd. All rights reserved.

Genitive Case-Marked Subject in Modern Mongolian

ERIC Educational Resources Information Center

Zayabaatar, Dalai; Dashdavaa, Vanchinsuren; Enkhjargal, Dagvasumberel; Onon, Tsulbaatar

2016-01-01

This paper presents peculiarities of the genitive case marked subject in Modern Mongolian. First, we argue that subordinate clauses with the genitive case-marked subject in Modern Mongolian are CP. Second, we provide an explanation for certain conditions of the genitive subject construction in Modern Mongolian (MM). Third, we attempt to show the…

Modern Written Arabic, Volume II.

ERIC Educational Resources Information Center

Naja, A. Nashat; Snow, James A.

This second volume of Modern Written Arabic builds on the previous volume and is the second step designed to teach members of the Foreign Service to read the modern Arabic press. The student will gain recognitional mastery of an extensive set of vocabulary items and will be more intensively exposed to wider and more complex morphological and…

The modern library: lost and found.

PubMed Central

Lindberg, D A

1996-01-01

The modern library, a term that was heard frequently in the mid-twentieth century, has fallen into disuse. The over-promotion of computers and all that their enthusiasts promised probably hastened its demise. Today, networking is transforming how libraries provide--and users seek--information. Although the Internet is the natural environment for the health sciences librarian, it is going through growing pains as we face issues of censorship and standards. Today's "modern librarian" must not only be adept at using the Internet but must become familiar with digital information in all its forms--images, full text, and factual data banks. Most important, to stay "modern," today's librarians must embark on a program of lifelong learning that will enable them to make optimum use of the advantages offered by modern technology. PMID:8938334

General practice--a post-modern specialty?

PubMed Central

Mathers, N; Rowland, S

1997-01-01

The 'modern' view of the world is based on the premise that we can discover the essential truth of the world using scientific method. The assumption is made that knowledge so acquired has been 'uncontaminated' by the mind of the investigator. Post-modern theory, however, is concerned with the process of knowing and how our minds are part of the process, i.e. our perceptions of reality and the relationships between different concepts are important influences on our ways of knowing. The values of post-modern theory are those of uncertainty, many different voices and experiences of reality and multifaceted descriptions of truth. These values are closer to our experience of general practice than the 'modern' values of scientific rationalism and should be reflected in a new curriculum for general practice. PMID:9167325

Local Solid Shape

PubMed Central

Koenderink, Jan; van Doorn, Andrea

2015-01-01

Local solid shape applies to the surface curvature of small surface patches—essentially regions of approximately constant curvatures—of volumetric objects that are smooth volumetric regions in Euclidean 3-space. This should be distinguished from local shape in pictorial space. The difference is categorical. Although local solid shape has naturally been explored in haptics, results in vision are not forthcoming. We describe a simple experiment in which observers judge shape quality and magnitude of cinematographic presentations. Without prior training, observers readily use continuous shape index and Casorati curvature scales with reasonable resolution. PMID:27648217

A probability tracking approach to segmentation of ultrasound prostate images using weak shape priors

NASA Astrophysics Data System (ADS)

Xu, Robert S.; Michailovich, Oleg V.; Solovey, Igor; Salama, Magdy M. A.

2010-03-01

Prostate specific antigen density is an established parameter for indicating the likelihood of prostate cancer. To this end, the size and volume of the gland have become pivotal quantities used by clinicians during the standard cancer screening process. As an alternative to manual palpation, an increasing number of volume estimation methods are based on the imagery data of the prostate. The necessity to process large volumes of such data requires automatic segmentation algorithms, which can accurately and reliably identify the true prostate region. In particular, transrectal ultrasound (TRUS) imaging has become a standard means of assessing the prostate due to its safe nature and high benefit-to-cost ratio. Unfortunately, modern TRUS images are still plagued by many ultrasound imaging artifacts such as speckle noise and shadowing, which results in relatively low contrast and reduced SNR of the acquired images. Consequently, many modern segmentation methods incorporate prior knowledge about the prostate geometry to enhance traditional segmentation techniques. In this paper, a novel approach to the problem of TRUS segmentation, particularly the definition of the prostate shape prior, is presented. The proposed approach is based on the concept of distribution tracking, which provides a unified framework for tracking both photometric and morphological features of the prostate. In particular, the tracking of morphological features defines a novel type of "weak" shape priors. The latter acts as a regularization force, which minimally bias the segmentation procedure, while rendering the final estimate stable and robust. The value of the proposed methodology is demonstrated in a series of experiments.

NDS modernization project - requirements analysis report

DOT National Transportation Integrated Search

1997-04-09

The National Distress System (NDS) Modernization Project envisions replacing/modernizing the present VHF-FM based system with an integrated state-of-the-art commercial/government-off- : the-shelf (COTS/GOTS) or non-developmental item (NDI) solution. ...

Is Twenty-First-Century Liberal Arts Modern?

ERIC Educational Resources Information Center

Tidbury, Iain

2018-01-01

In the first part of this paper I explore a recently conceived notion of a modern liberal arts education which brings the ancient Aristotelian search for first principles into a modern metaphysics of Kant and Hegel. In the second part I examine two ways in which this modern conception of a liberal arts education intervenes in important social and…

Phylogenetic assemblage structure of North American trees is more strongly shaped by glacial-interglacial climate variability in gymnosperms than in angiosperms.

PubMed

Ma, Ziyu; Sandel, Brody; Svenning, Jens-Christian

2016-05-01

How fast does biodiversity respond to climate change? The relationship of past and current climate with phylogenetic assemblage structure helps us to understand this question. Studies of angiosperm tree diversity in North America have already suggested effects of current water-energy balance and tropical niche conservatism. However, the role of glacial-interglacial climate variability remains to be determined, and little is known about any of these relationships for gymnosperms. Moreover, phylogenetic endemism, the concentration of unique lineages in restricted ranges, may also be related to glacial-interglacial climate variability and needs more attention. We used a refined phylogeny of both angiosperms and gymnosperms to map phylogenetic diversity, clustering and endemism of North American trees in 100-km grid cells, and climate change velocity since Last Glacial Maximum together with postglacial accessibility to recolonization to quantify glacial-interglacial climate variability. We found: (1) Current climate is the dominant factor explaining the overall patterns, with more clustered angiosperm assemblages toward lower temperature, consistent with tropical niche conservatism. (2) Long-term climate stability is associated with higher angiosperm endemism, while higher postglacial accessibility is linked to to more phylogenetic clustering and endemism in gymnosperms. (3) Factors linked to glacial-interglacial climate change have stronger effects on gymnosperms than on angiosperms. These results suggest that paleoclimate legacies supplement current climate in shaping phylogenetic patterns in North American trees, and especially so for gymnosperms.

Sixth International Limnogeology Congress: field trip guidebook, Reno, Nevada, June 15-19, 2015

USGS Publications Warehouse

Rosen, Michael R.

2015-01-01

The U.S. Geological Survey has sponsored each ILIC that has been held in the United States because of the importance of understanding paleoclimate and contaminant histories of lakes, two main themes of the Congress. This field trip guide provides a permanent record of some of the wide variety of studies that are being conducted in modern lakes and ancient lake deposits in western North America, and it provides a starting point for any one desiring to visit these exceptional sites or begin work in these areas.

Mendel in the Modern Classroom

ERIC Educational Resources Information Center

Smith, Mike U.; Gericke, Niklas M.

2015-01-01

Mendel is an icon in the history of genetics and part of our common culture and modern biology instruction. The aim of this paper is to summarize the place of Mendel in the modern biology classroom. In the present article we will identify key issues that make Mendel relevant in the classroom today. First, we recount some of the historical…

Demographic Events and Evolutionary Forces Shaping European Genetic Diversity

PubMed Central

Veeramah, Krishna R.; Novembre, John

2014-01-01

Europeans have been the focus of some of the largest studies of genetic diversity in any species to date. Recent genome-wide data have reinforced the hypothesis that present-day European genetic diversity is strongly correlated with geography. The remaining challenge now is to understand more precisely how patterns of diversity in Europe reflect ancient demographic events such as postglacial expansions or the spread of farming. It is likely that recent advances in paleogenetics will give us some of these answers. There has also been progress in identifying specific segments of European genomes that reflect adaptations to selective pressures from the physical environment, disease, and dietary shifts. A growing understanding of how modern European genetic diversity has been shaped by demographic and evolutionary forces is not only of basic historical and anthropological interest but also aids genetic studies of disease. PMID:25059709

Do rats use shape to solve “shape discriminations”?

PubMed Central

Minini, Loredana; Jeffery, Kathryn J.

2006-01-01

Visual discrimination tasks are increasingly used to explore the neurobiology of vision in rodents, but it remains unclear how the animals solve these tasks: Do they process shapes holistically, or by using low-level features such as luminance and angle acuity? In the present study we found that when discriminating triangles from squares, rats did not use shape but instead relied on local luminance differences in the lower hemifield. A second experiment prevented this strategy by using stimuli—squares and rectangles—that varied in size and location, and for which the only constant predictor of reward was aspect ratio (ratio of height to width: a simple descriptor of “shape”). Rats eventually learned to use aspect ratio but only when no other discriminand was available, and performance remained very poor even at asymptote. These results suggest that although rats can process both dimensions simultaneously, they do not naturally solve shape discrimination tasks this way. This may reflect either a failure to visually process global shape information or a failure to discover shape as the discriminative stimulus in a simultaneous discrimination. Either way, our results suggest that simultaneous shape discrimination is not a good task for studies of visual perception in rodents. PMID:16705141

Paleoclimate

USGS Publications Warehouse

Bartlein, Patrick J.; Hostetler, Steven W.; Alder, Jay R.; Ohring, G.

2014-01-01

As host to one of the major continental-scale ice sheets, and with considerable spatial variability of climate related to its physiography and location, North America has experienced a wide range of climates over time. The aim of this chapter is to review the history of those climate variations, focusing in particular on the continental-scale climatic variations between the Last Glacial Maximum (LGM, ca. 21,000 years ago or 21 ka) and the present, which were as large in amplitude as any experienced over a similar time span during the past several million years. As background to that discussion, the climatic variations over the Cenozoic (the past 65.5 Myr, or 65.5 Ma to present) that led ultimately to the onset of Northern Hemisphere glaciation at 2.59 Ma will also be discussed. Superimposed on the large-amplitude, broad-scale variations from the LGM to present, are climatic variations on millennial-to-decadal scales, and these will be reviewed in particular for the Holocene (11.7 ka to present) and the past millennium.

Shape component analysis: structure-preserving dimension reduction on biological shape spaces.

PubMed

Lee, Hao-Chih; Liao, Tao; Zhang, Yongjie Jessica; Yang, Ge

2016-03-01

Quantitative shape analysis is required by a wide range of biological studies across diverse scales, ranging from molecules to cells and organisms. In particular, high-throughput and systems-level studies of biological structures and functions have started to produce large volumes of complex high-dimensional shape data. Analysis and understanding of high-dimensional biological shape data require dimension-reduction techniques. We have developed a technique for non-linear dimension reduction of 2D and 3D biological shape representations on their Riemannian spaces. A key feature of this technique is that it preserves distances between different shapes in an embedded low-dimensional shape space. We demonstrate an application of this technique by combining it with non-linear mean-shift clustering on the Riemannian spaces for unsupervised clustering of shapes of cellular organelles and proteins. Source code and data for reproducing results of this article are freely available at https://github.com/ccdlcmu/shape_component_analysis_Matlab The implementation was made in MATLAB and supported on MS Windows, Linux and Mac OS. geyang@andrew.cmu.edu. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Analytical study on different blade-shape design of HAWT for wasted kinetic energy recovery system (WKERS)

NASA Astrophysics Data System (ADS)

Goh, J. B.; Jamaludin, Z.; Jafar, F. A.; Mat Ali, M.; Mokhtar, M. N. Ali; Tan, C. H.

2017-06-01

Wasted kinetic energy recovery system (WKERS) is a wind renewable gadget installed above a cooling tower outlet to harvest the discharged wind for electrical regeneration purpose. The previous WKERS is operated by a horizontal axis wind turbine (HAWT) with delta blade design but the performance is still not at the optimum level. Perhaps, a better blade-shape design should be determined to obtain the optimal performance, as it is believed that the blade-shape design plays a critical role in HAWT. Hence, to determine a better blade-shape design for a new generation of WKERS, elliptical blade, swept blade and NREL Phase IV blade are selected for this benchmarking process. NREL Phase IV blade is a modern HAWT’s blade design by National Renewable Energy Laboratory (NREL) research lab. During the process of benchmarking, Computational Fluid Dynamics (CFD) analysis was ran by using SolidWorks design software, where all the designs are simulated with linear flow simulation. The wind speed in the simulation is set at 10.0 m/s, which is compatible with the average wind speed produced by a standard size cooling tower. The result is obtained by flow trajectories of air motion, surface plot and cut plot of the applied blade-shape. Besides, the aspect ratio of each blade is calculated and included as one of the reference in the comparison. Hence, the final selection of the best blade-shape design will bring to the new generation of WKERS.

Information Geometry for Landmark Shape Analysis: Unifying Shape Representation and Deformation

PubMed Central

Peter, Adrian M.; Rangarajan, Anand

2010-01-01

Shape matching plays a prominent role in the comparison of similar structures. We present a unifying framework for shape matching that uses mixture models to couple both the shape representation and deformation. The theoretical foundation is drawn from information geometry wherein information matrices are used to establish intrinsic distances between parametric densities. When a parameterized probability density function is used to represent a landmark-based shape, the modes of deformation are automatically established through the information matrix of the density. We first show that given two shapes parameterized by Gaussian mixture models (GMMs), the well-known Fisher information matrix of the mixture model is also a Riemannian metric (actually, the Fisher-Rao Riemannian metric) and can therefore be used for computing shape geodesics. The Fisher-Rao metric has the advantage of being an intrinsic metric and invariant to reparameterization. The geodesic—computed using this metric—establishes an intrinsic deformation between the shapes, thus unifying both shape representation and deformation. A fundamental drawback of the Fisher-Rao metric is that it is not available in closed form for the GMM. Consequently, shape comparisons are computationally very expensive. To address this, we develop a new Riemannian metric based on generalized ϕ-entropy measures. In sharp contrast to the Fisher-Rao metric, the new metric is available in closed form. Geodesic computations using the new metric are considerably more efficient. We validate the performance and discriminative capabilities of these new information geometry-based metrics by pairwise matching of corpus callosum shapes. We also study the deformations of fish shapes that have various topological properties. A comprehensive comparative analysis is also provided using other landmark-based distances, including the Hausdorff distance, the Procrustes metric, landmark-based diffeomorphisms, and the bending energies of the

Materials ``alchemy'': Shape-preserving chemical transformation of micro-to-macroscopic 3-D structures

NASA Astrophysics Data System (ADS)

Sandhage, Kenneth H.

2010-06-01

The scalable fabrication of nano-structured materials with complex morphologies and tailorable chemistries remains a significant challenge. One strategy for such synthesis consists of the generation of a solid structure with a desired morphology (a “preform”), followed by reactive conversion of the preform into a new chemistry. Several gas/solid and liquid/solid reaction processes that are capable of such chemical conversion into new micro-to-nano-structured materials, while preserving the macroscopic-to-microscopic preform morphologies, are described in this overview. Such shape-preserving chemical transformation of one material into another could be considered a modern type of materials “alchemy.”

Modernity, mental illness and the crisis of meaning.

PubMed

Roberts, M

2007-05-01

Western civilization has, over its relatively recent past, undergone dramatic, unparalleled changes. The historical period in which these changes have occurred is commonly referred to as 'modernity', and although modernity has had profound repercussions on all aspects of people's lives, what has received less attention in the nursing literature is how modernity has influenced, and continues to influence, the mental health of modern men and women. In an attempt to address this, the following paper, drawing on the work of Szasz, Nietzsche and Frankl, seeks to present an accessible introduction to one of the most salient features of modernity; namely, the erosion of those traditions that gave life a meaning or a purpose, and that provided people with ready answers to the problem of how they ought to live. The paper will then introduce some of the possible consequences of this on the mental health of modern men and women, as well as providing preliminary suggestions as to how mental health nursing might respond. In doing so, the paper also seeks to stimulate further discussion and research into how modernity has influenced, and continues to influence, the mental health of modern men and women, and how psychiatric and mental health nursing might respond.

Modernizing Electricity Delivery

EPA Pesticide Factsheets

Explains how modern grid, or smart grid, investments can enable grid operators to respond faster to changes in grid conditions and allow for two-way communication between utilities and electricity end-users.

Studying Innovation Technologies in Modern Education

ERIC Educational Resources Information Center

Stukalenko, Nina M.; Zhakhina, Bariya B.; Kukubaeva, Asiya K.; Smagulova, Nurgul K.; Kazhibaeva, Gulden K.

2016-01-01

In modern society, innovation technologies expand to almost every field of human activity, including such wide field as education. Due to integrating innovation technologies into the educational process practice, this phenomenon gained special significance within improvement and modernization of the established educational system. Currently, the…

Microbial shaping of wrinkle structures in siliciclastic deposits

NASA Astrophysics Data System (ADS)

Bosak, T.; Mariotti, G.; Pruss, S. B.; Perron, J.; O'Grady, M.

2013-12-01

Wrinkle structures are millimeter- to centimeter-scale elongated or reticulate sedimentary structures that resemble symmetric ripples. Sharp-crested and flat-topped wrinkle structures up to 1 cm wide occur on numerous bedding planes in the Neoproterozoic and Cambrian, as well as in some Archean and Phanerozoic siliciclastic deposits. Because similar, but unlithified structures occur in some modern, microbially-colonized sands, wrinkle structures are typically interpreted as microbially induced sedimentary structures. However, it is unclear if physical processes, such as the motion of suspended sand grains, can produce similar features in sand even before microbial colonization. We introduced mat fragments to the surface of silica sand in wave tanks and generated sharp-crested, flat-topped and pitted wrinkle structures. The abrasion of the sandy surface by rolling, low density, millimeter-size fragments of microbial mats produces wrinkle structures at extremely weak orbital velocities that cannot move sand grains in the absence of light particles. Wrinkle structures form in a few hours and can become colonized by microbial mats within weeks. Thus, wrinkle structures are patterns formed by microbially mediated sand motion at low orbital velocities in the absence of bioturbation. Once formed, wrinkle structures can be colonized and stabilized by microbial mats, but the shape of these mats does not dictate the shape of wrinkle structures. These experiments bolster the interpretation of wrinkle structures as morphological signatures of organic particles and early life in Archean and Proterozoic siliciclastic deposits.

Pose-oblivious shape signature.

PubMed

Gal, Ran; Shamir, Ariel; Cohen-Or, Daniel

2007-01-01

A 3D shape signature is a compact representation for some essence of a shape. Shape signatures are commonly utilized as a fast indexing mechanism for shape retrieval. Effective shape signatures capture some global geometric properties which are scale, translation, and rotation invariant. In this paper, we introduce an effective shape signature which is also pose-oblivious. This means that the signature is also insensitive to transformations which change the pose of a 3D shape such as skeletal articulations. Although some topology-based matching methods can be considered pose-oblivious as well, our new signature retains the simplicity and speed of signature indexing. Moreover, contrary to topology-based methods, the new signature is also insensitive to the topology change of the shape, allowing us to match similar shapes with different genus. Our shape signature is a 2D histogram which is a combination of the distribution of two scalar functions defined on the boundary surface of the 3D shape. The first is a definition of a novel function called the local-diameter function. This function measures the diameter of the 3D shape in the neighborhood of each vertex. The histogram of this function is an informative measure of the shape which is insensitive to pose changes. The second is the centricity function that measures the average geodesic distance from one vertex to all other vertices on the mesh. We evaluate and compare a number of methods for measuring the similarity between two signatures, and demonstrate the effectiveness of our pose-oblivious shape signature within a 3D search engine application for different databases containing hundreds of models.

Reframing Romaine Brooks' heroic queer modernism.

PubMed

Langer, Cassandra L

2010-01-01

Modernism was not a wholesale embracing of Greenberg's definition as abstracting, non-objective, and autonomous. The expatriate U.S. artist and lesbian Romaine Brooks politicized her portraits of females based on a queer combination of the Byronic erotic and Baudelaire's modern dandy. Her execution of her queer modernist aesthetics re-presents female heroes as part of a self-reflective dynamic of lesbian modernity that emphasizes the ambiguity of normative gender binaries and plays with style, personality, and impersonation as disrupting to bourgeoisie mores. My focus is on how Brooks shatters normative conventions of portraiture in her revolutionary critique of heteronormativity.

Paleoclimate Signals and Age Distributions from 41 Public Water Works in the Netherlands

NASA Astrophysics Data System (ADS)

Broers, H. P.; Weert, J. D.; Sültenfuß, J.; Aeschbach, W.; Vonhof, H.; Casteleijns, J.

2015-12-01

waters from this graben structure exhibit clear paleoclimate signals, with a clear relations between NGT (ranging from 2,8 -9 °C), 4He (up to 3.3E-6 cc STP/g) and 18O (range from -8.5—5.5‰). Moreover, ¾ ratios of these graben waters suggest an influx of He from mantle origin.

Modern dust aerosol availability in northwestern China.

PubMed

Wang, Xunming; Cheng, Hong; Che, Huizheng; Sun, Jimin; Lu, Huayu; Qiang, Mingrui; Hua, Ting; Zhu, Bingqi; Li, Hui; Ma, Wenyong; Lang, Lili; Jiao, Linlin; Li, Danfeng

2017-08-18

The sources of modern dust aerosols and their emission magnitudes are fundamental for linking dust with climate and environment. Using field sample data, wind tunnel experiments and statistical analysis, we determined the contributions of wadis, gobi (stony desert), lakebeds, riverbeds, and interdunes to modern dust aerosol availability in the three important potential dust sources including the Tarim Basin, Qaidam Basin, and Ala Shan Plateau of China. The results show that riverbeds are the dominant landscape for modern dust aerosol availabilities in the Qaidam Basin, while wadis, gobi, and interdunes are the main landscapes over the Ala Shan Plateau and Tarim Basin. The Ala Shan Plateau and Tarim Basin are potential dust sources in northwestern China, while the Qaidam Basin is not a major source of the modern dust aerosols nowadays, and it is not acting in a significant way to the Loess Plateau presently. Moreover, most of modern dust aerosol emissions from China originated from aeolian processes with low intensities rather than from major dust events.

Optimal design of UAV's pod shape

NASA Astrophysics Data System (ADS)

Wei, Qun; Jia, Hong-guang

2011-08-01

In the modern war, UAV(unmanned aircraft system) plays a more and more important role in the army. UAVs always carry electrical-optical reconnaissance systems. These systems are used to accomplish the missions of observing and reconnaissance the battlefield. For traditional UAV, the shape of the pod on UAV is sphericity. In addition, the pod of UAV not only has the job of observing and reconnaissance the battlefield, but its shape also has impact on the UAV's drag when it flies in the air. In this paper, two different kinds of pod models are set up, one is the traditional sphericity model, the other is a new model. Unstructured grid is used on the flow field. Using CFD(computational fluid dynamic) method, the results of the drags of the different kinds of pod are got. The drag's relationship between the pod and the UAV is obtained by comparing the results of simulations. After analyzing the results we can get: when UAV flies at low speed(0.3Ma{0.7Ma), the drag's difference between the two kinds of pod is little, the pod's drag takes a small part of the UAV's whole drag which is only about 14%. At transonic speed(0.8Ma{1.2Ma), the drag's difference between these two kinds of pod is getting bigger and bigger along with the speed goes higher. The traditional pod's drag is 1/3 of the UAV's whole drag value, but for the new pod, it is only 1/5. At supersonic speed(1.3Ma{2.0Ma), the traditional pod's drag goes up rapidly, but the new kind of pod's drag goes up slowly. This makes the difference between the two kinds of UAVs' total drag comes greater. For example, at 2Ma, the total drag of new UAV is only 2/3 of the traditional UAV. These results show: when the UAV flies at low speed, these two kinds of pod have little difference in drag. But if it flies at supersonic speed, the pod has great impact on the UAV's total drag, so the designer of UAV's pod should pay more attention on the out shape.

Terradynamically streamlined shapes in animals and robots enhance traversability through densely cluttered terrain.

PubMed

Li, Chen; Pullin, Andrew O; Haldane, Duncan W; Lam, Han K; Fearing, Ronald S; Full, Robert J

2015-06-22

Many animals, modern aircraft, and underwater vehicles use fusiform, streamlined body shapes that reduce fluid dynamic drag to achieve fast and effective locomotion in air and water. Similarly, numerous small terrestrial animals move through cluttered terrain where three-dimensional, multi-component obstacles like grass, shrubs, vines, and leaf litter also resist motion, but it is unknown whether their body shape plays a major role in traversal. Few ground vehicles or terrestrial robots have used body shape to more effectively traverse environments such as cluttered terrain. Here, we challenged forest-floor-dwelling discoid cockroaches (Blaberus discoidalis) possessing a thin, rounded body to traverse tall, narrowly spaced, vertical, grass-like compliant beams. Animals displayed high traversal performance (79 ± 12% probability and 3.4 ± 0.7 s time). Although we observed diverse obstacle traversal strategies, cockroaches primarily (48 ± 9% probability) used a novel roll maneuver, a form of natural parkour, allowing them to rapidly traverse obstacle gaps narrower than half their body width (2.0 ± 0.5 s traversal time). Reduction of body roundness by addition of artificial shells nearly inhibited roll maneuvers and decreased traversal performance. Inspired by this discovery, we added a thin, rounded exoskeletal shell to a legged robot with a nearly cuboidal body, common to many existing terrestrial robots. Without adding sensory feedback or changing the open-loop control, the rounded shell enabled the robot to traverse beam obstacles with gaps narrower than shell width via body roll. Such terradynamically 'streamlined' shapes can reduce terrain resistance and enhance traversability by assisting effective body reorientation via distributed mechanical feedback. Our findings highlight the need to consider body shape to improve robot mobility in real-world terrain often filled with clutter, and to develop better locomotor-ground contact models to understand

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

Toward a Post-Modern Agenda in Instructional Technology.

ERIC Educational Resources Information Center

Solomon, David L.

2000-01-01

Discusses the concept of post-modernism and relates it to the field of instructional technology. Topics include structuralism; semiotics; poststructuralism; deconstruction; knowledge and power; critical theory; self-concept; post-modern assumptions; and potential contributions of post-modern concepts in instructional technology. (Contains 80…

Ontogeny of modern human longitudinal body and transverse shoulder proportions.

PubMed

Frelat, Mélanie A; Coquerelle, Michael; Trinkaus, Erik

2017-03-01

Whereas variation of modern human adult body size and shape has been widely studied in the context of ecogeographical clines, little is known about the differential growth patterns of transverse and longitudinal dimensions among human populations. Our study explored the ontogenetic variation of those body proportions in modern humans. We compared results from four different approaches to study cross-sectional skeletal samples of Africans (n = 43), Amerindians (n = 69) and Europeans (n = 40) from 0 to 14 years of age. Clavicle, humerus, and femur intermetaphyseal lengths, and femoral distal metaphyseal breadth, were measured. Average ontogenetic trajectories were computed in order to compare the growth patterns of the three groups. Our findings demonstrated that the three geographical groups shared similar absolute and relative patterns of change with age for the four dimensions considered. Although interpopulation differences existed in transverse to longitudinal as well as in interlimb proportions, those differences did not seem to remain constant throughout ontogeny, similar to what has been shown for intralimb proportions. Growth rates of transverse shoulder proportions differed between populations from different regions after 10 years, whereas those for longitudinal proportions were very similar. The ontogeny of transverse shoulder proportions is more complex than what is observed for bi-iliac breadth, suggesting that transverse shoulder to limb proportions are not solely influenced by ecogeographical conditions. Our analysis demonstrates that methodologies that incorporate critical dimensions of body form could shed new light on human adaptation in both paleontological and neontological contexts. © 2016 Wiley Periodicals, Inc.

Control of Chemical Dynamics Using Arbitrary Shaped Optical Pulses and Laser-Enhanced NMR Spectroscopy.

NASA Astrophysics Data System (ADS)

Goswami, Debabrata

A key feature of this thesis is the application of novel laser techniques to various fields of spectroscopy. The overall effort has been towards achieving either chemical control or enhanced spectroscopic resolution. The issue of chemical control forms the major bulk. Over the past decade, theoretical and technological developments have made it possible for a modern day chemist to be a more active participant in nature's chemical processes. Consequently, although the idea of manipulating chemical reactions has been a long term dream, it is only now that realization of such dreams has become realistic. One of the major contributions that is leading towards this realization is the development of pulse shaping techniques. Here, we concentrate on the important developments in this area that has come by recently, particularly emphasizing new results from our laboratory. We discuss in detail the current state-of-the-art, and present some experimental and theoretical demonstrations of chemical control by using arbitrarily shaped pulses. The major strength of our approach to pulse shaping has been in considering "robustness in the laboratory" as a primary constraint. Most of the shapes, addressed here, work under adiabatic conditions where the exact shape of the pulse is not critical as long as the basic criteria dictated by the adiabatic theorem are satisfied. A novel approach of "molecular pulse shaping"--using the molecule itself to generate its own pulse shape--is presented as an example of the ultimate form of robustness. Finally, we get into the issue of resolution enhancement by coupling laser radiation into a Nuclear Magnetic Resonance (NMR) spectrometer. Spectroscopic resolution enhancement is an everlasting effort in the field of NMR--even more for biological NMR. We present some of the recent experimental findings in our laboratory that show selective dispersion in the NMR spectrum when it is acquired under a non-resonant laser irradiation of the sample. Albeit

"On Making Man Modern"--A Review.

ERIC Educational Resources Information Center

Rivera, William M.

A. Inkeles' cross-cultural work is reviewed. Inkeles studied young factory workers in six developing countries (Argentina, Chile, India, Israel, Nigeria, and East Pakistan) to determine their "modernity" characteristics versus their "traditional" or rural orientations. The use of the "modern man" thesis in this study,…

Modern Airfoil Ice Accretions

NASA Technical Reports Server (NTRS)

Addy, Harold E., Jr.; Potapczuk, Mark G.; Sheldon, David W.

1997-01-01

This report presents results from the first icing tests performed in the Modem Airfoils program. Two airfoils have been subjected to icing tests in the NASA Lewis Icing Research Tunnel (IRT). Both airfoils were two dimensional airfoils; one was representative of a commercial transport airfoil while the other was representative of a business jet airfoil. The icing test conditions were selected from the FAR Appendix C envelopes. Effects on aerodynamic performance are presented including the effects of varying amounts of glaze ice as well as the effects of approximately the same amounts of glaze, mixed, and rime ice. Actual ice shapes obtained in these tests are also presented for these cases. In addition, comparisons are shown between ice shapes from the tests and ice shapes predicted by the computer code, LEWICE for similar conditions. Significant results from the tests are that relatively small amounts of ice can have nearly as much effect on airfoil lift coefficient as much greater amounts of ice and that glaze ice usually has a more detrimental effect than either rime or mixed ice. LEWICE predictions of ice shapes, in general, compared reasonably well with ice shapes obtained in the IRT, although differences in details of the ice shapes were observed.

Shaped Recess Flow Control

NASA Technical Reports Server (NTRS)

Shyam, Vikram (Inventor); Poinsatte, Philip (Inventor); Thurman, Douglas (Inventor)

2017-01-01

One or more embodiments of techniques or systems for shaped recess flow control are provided herein. A shaped recess or cavity can be formed on a surface associated with fluid flow. The shaped recess can be configured to create or induce fluid effects, temperature effects, or shedding effects that interact with a free stream or other structures. The shaped recess can be formed at an angle to a free stream flow and may be substantially "V" shaped. The shaped recess can be coupled with a cooling channel, for example. The shaped recess can be upstream or downstream from a cooling channel and aligned in a variety of manners. Due to the fluid effects, shedding effects, and temperature effects created by a shaped recess, lift-off or separation of cooling jets of cooling channels can be mitigated, thereby enhancing film cooling effectiveness.

General shape optimization capability

NASA Technical Reports Server (NTRS)

Chargin, Mladen K.; Raasch, Ingo; Bruns, Rudolf; Deuermeyer, Dawson

1991-01-01

A method is described for calculating shape sensitivities, within MSC/NASTRAN, in a simple manner without resort to external programs. The method uses natural design variables to define the shape changes in a given structure. Once the shape sensitivities are obtained, the shape optimization process is carried out in a manner similar to property optimization processes. The capability of this method is illustrated by two examples: the shape optimization of a cantilever beam with holes, loaded by a point load at the free end (with the shape of the holes and the thickness of the beam selected as the design variables), and the shape optimization of a connecting rod subjected to several different loading and boundary conditions.

Pulse shaping system

DOEpatents

Skeldon, Mark D.; Letzring, Samuel A.

1999-03-23

Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

Pulse shaping system

DOEpatents

Skeldon, M.D.; Letzring, S.A.

1999-03-23

Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses. 8 figs.

Isotope hydrology of deep groundwater in Syria: renewable and non-renewable groundwater and paleoclimate impact

NASA Astrophysics Data System (ADS)

Al-Charideh, A.; Kattaa, B.

2016-02-01

The Regional Deep Cretaceous Aquifer (RDCA) is the principal groundwater resource in Syria. Isotope and hydrochemical data have been used to evaluate the geographic zones in terms of renewable and non-renewable groundwater and the inter-relation between current and past recharge. The chemical and isotopic character of groundwater together with radiometric 14C data reflect the existence of three different groundwater groups: (1) renewable groundwater, in RDCA outcropping areas, in western Syria along the Coastal and Anti-Lebanon mountains. The mean δ18O value (-7.2 ‰) is similar to modern precipitation with higher 14C values (up to 60-80 pmc), implying younger groundwater (recent recharge); (2) semi-renewable groundwater, which is located in the unconfined section of the RDCA and parallel to the first zone. The mean δ18O value (-7.0 ‰) is also similar to modern precipitation with a 14C range of 15-45 pmc; (3) non-renewable groundwater found in most of the Syrian interior, where the RDCA becomes confined. A considerable depletion in δ18O (-8.0 ‰) relative to the modern rainfall and low values of 14C (<15 pmc) suggest that the large masses of deep groundwater are non-renewable and related to an older recharge period. The wide scatter of all data points around the two meteoric lines in the δ18O-δ2H diagram indicates considerable variation in recharge conditions. There is limited renewable groundwater in the mountain area, and most of the stored deep groundwater in the RDCA is non-renewable, with corrected 14C ages varying between 10 and 35 Kyr BP.

An evaluation of nasal bone and aperture shape among three South African populations.

PubMed

McDowell, Jennifer L; Kenyhercz, Michael W; L'Abbé, Ericka N

2015-07-01

Reliable and valid population specific standards are necessary to accurately develop a biological profile, which includes an estimation of peer-reported social identification (Hefner, 2009). During the last 300 years, colonialism, slavery and apartheid created geographic, physical and social divisions of population groups in South Africa. The purpose of this study was to evaluate variation in nasal bone and aperture shape in a modern population of black, white, and coloured South Africans using standard craniometric variables and geometric morphometrics, namely general Procrustes and elliptical Fourier analyses. Fourteen standard landmarks were digitally recorded or computationally derived from 310 crania using a 3D coordinate digitizer for discriminant function, principal components and generalized Procrustes analyses. For elliptical Fourier analysis, outlines of the nasal aperture were generated from standardized photographs. All classification accuracies were better than chance; the lowest accuracies were for coloured and the highest accuracies were for white South Africans. Most difficulties arose in distinguishing coloured and black South African groups from each other. Generally, misclassifications were noted between the sexes within each group rather than among groups, which suggests that sex has less influence on nasal bone and aperture shape than ancestry. Quantifiable variation in shape of the nasal aperture region between white and non-white South African groups was observed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

On the Emergence of Modern Humans

ERIC Educational Resources Information Center

Amati, Daniele; Shallice, Tim

2007-01-01

The emergence of modern humans with their extraordinary cognitive capacities is ascribed to a novel type of cognitive computational process (sustained non-routine multi-level operations) required for abstract projectuality, held to be the common denominator of the cognitive capacities specific to modern humans. A brain operation (latching) that…

Holocene climate variability in Texas, USA: An integration of existing paleoclimate data and modeling with a new, high-resolution speleothem record

USGS Publications Warehouse

Wong, Corinne I.; Banner, Jay L.; Musgrove, MaryLynn

2015-01-01

Delineating the climate processes governing precipitation variability in drought-prone Texas is critical for predicting and mitigating climate change effects, and requires the reconstruction of past climate beyond the instrumental record. We synthesize existing paleoclimate proxy data and climate simulations to provide an overview of climate variability in Texas during the Holocene. Conditions became progressively warmer and drier transitioning from the early to mid Holocene, culminating between 7 and 3 ka (thousand years ago), and were more variable during the late Holocene. The timing and relative magnitude of Holocene climate variability, however, is poorly constrained owing to considerable variability among the different records. To help address this, we present a new speleothem (NBJ) reconstruction from a central Texas cave that comprises the highest resolution proxy record to date, spanning the mid to late Holocene. NBJ trace-element concentrations indicate variable moisture conditions with no clear temporal trend. There is a decoupling between NBJ growth rate, trace-element concentrations, and δ18O values, which indicate that (i) the often direct relation between speleothem growth rate and moisture availability is likely complicated by changes in the overlying ecosystem that affect subsurface CO2 production, and (ii) speleothem δ18O variations likely reflect changes in moisture source (i.e., proportion of Pacific-vs. Gulf of Mexico-derived moisture) that appear not to be linked to moisture amount.

Holocene climate variability in Texas, USA: An integration of existing paleoclimate data and modeling with a new, high-resolution speleothem record

NASA Astrophysics Data System (ADS)

Wong, Corinne I.; Banner, Jay L.; Musgrove, MaryLynn

2015-11-01

Delineating the climate processes governing precipitation variability in drought-prone Texas is critical for predicting and mitigating climate change effects, and requires the reconstruction of past climate beyond the instrumental record. We synthesize existing paleoclimate proxy data and climate simulations to provide an overview of climate variability in Texas during the Holocene. Conditions became progressively warmer and drier transitioning from the early to mid Holocene, culminating between 7 and 3 ka (thousand years ago), and were more variable during the late Holocene. The timing and relative magnitude of Holocene climate variability, however, is poorly constrained owing to considerable variability among the different records. To help address this, we present a new speleothem (NBJ) reconstruction from a central Texas cave that comprises the highest resolution proxy record to date, spanning the mid to late Holocene. NBJ trace-element concentrations indicate variable moisture conditions with no clear temporal trend. There is a decoupling between NBJ growth rate, trace-element concentrations, and δ18O values, which indicate that (i) the often direct relation between speleothem growth rate and moisture availability is likely complicated by changes in the overlying ecosystem that affect subsurface CO2 production, and (ii) speleothem δ18O variations likely reflect changes in moisture source (i.e., proportion of Pacific-vs. Gulf of Mexico-derived moisture) that appear not to be linked to moisture amount.

Modern human origins: progress and prospects.

PubMed Central

Stringer, Chris

2002-01-01

The question of the mode of origin of modern humans (Homo sapiens) has dominated palaeoanthropological debate over the last decade. This review discusses the main models proposed to explain modern human origins, and examines relevant fossil evidence from Eurasia, Africa and Australasia. Archaeological and genetic data are also discussed, as well as problems with the concept of 'modernity' itself. It is concluded that a recent African origin can be supported for H. sapiens, morphologically, behaviourally and genetically, but that more evidence will be needed, both from Africa and elsewhere, before an absolute African origin for our species and its behavioural characteristics can be established and explained. PMID:12028792

Modernity, postmodernity and disability in developing countries.

PubMed

Lysack, C

1997-06-01

This paper examines the implications of two theoretical perspectives, modernity and postmodernity, for provision of community-based disability services in developing countries. The author argues that modernity's embrace of the 'wonders' of science and technology have significantly affected our understanding of what community is. Modernity, in fact, leads us to view communities in one of two major ways: as inferior, or as ideal. Both views are deeply flawed. Postmodernity's profound scepticism of truth claims and authority provides a useful critique of community conceived in modern terms. The critique is helpful to the extent that it reveals the power of language in constructing our ideas of community. It also highlights a new way of thinking about participation, individualism and choice in community disability initiatives.

Science for Survival: The Modern Synthesis of Evolution and The Biological Sciences Curriculum Study

NASA Astrophysics Data System (ADS)

Green, Lisa Anne

In this historical dissertation, I examined the process of curriculum development in the Biological Sciences Curriculum Study (BSCS) in the United States during the period 1959-1963. The presentation of evolution in the high school texts was based on a more robust form of Darwinian evolution which developed during the 1930s and 1940s called "the modern synthesis of evolution." Building primarily on the work of historians Vassiliki Smocovitis and John L. Rudolph, I used the archival papers and published writings of the four architects of the modern synthesis and the four most influential leaders of the BSCS in regards to evolution to investigate how the modern synthetic theory of evolution shaped the BSCS curriculum. The central question was "Why was evolution so important to the BSCS to make it the central theme of the texts?" Important answers to this question had already been offered in the historiography, but it was still not clear why every citizen in the world needed to understand evolution. I found that the emphasis on natural selection in the modern synthesis shifted the focus away from humans as passive participants to the recognition that humans are active agents in their own cultural and biological evolution. This required re-education of the world citizenry, which was accomplished in part by the BSCS textbooks. I also found that BSCS leaders Grobman, Glass, and Muller had serious concerns regarding the effects of nuclear radiation on the human gene pool, and were actively involved in informing th public. Lastly, I found that concerns of 1950s reform eugenicists were addressed in the BSCS textbooks, without mentioning eugenics by name. I suggest that the leaders of the BSCS, especially Bentley Glass and Hermann J. Muller, thought that students needed to understand genetics and evolution to be able to make some of the tough choices they might be called on to make as the dominant species on earth and the next reproductive generation in the nuclear age. This

Analysis of Computational Models of Shaped Charges for Jet Formation and Penetration

NASA Astrophysics Data System (ADS)

Haefner, Jonah; Ferguson, Jim

2016-11-01

Shaped charges came into use during the Second World War demonstrating the immense penetration power of explosively formed projectiles and since has become a tool used by nearly every nation in the world. Penetration is critically dependent on how the metal liner is collapsed into a jet. The theory of jet formation has been studied in depth since the late 1940s, based on simple models that neglect the strength and compressibility of the metal liner. Although attempts have been made to improve these models, simplifying assumptions limit the understanding of how the material properties affect the jet formation. With a wide range of material and strength models available for simulation, a validation study was necessary to guide code users in choosing models for shaped charge simulations. Using PAGOSA, a finite-volume Eulerian hydrocode designed to model hypervelocity materials and strong shock waves developed by Los Alamos National Laboratory, and experimental data, we investigated the effects of various equations of state and material strength models on jet formation and penetration of a steel target. Comparing PAGOSA simulations against modern experimental data, we analyzed the strengths and weaknesses of available computational models. LA-UR-16-25639 Los Alamos National Laboratory.

Select, High-Resolution Windows Into Sub-Centennial-Scale Climate Variability in the Western Pacific Warm Pool Between 7 and 12 ka

NASA Astrophysics Data System (ADS)

Quinn, T. M.; Taylor, F. W.; Cheng, H.; Edwards, R. L.; Burr, G.; Chen, Y.

2004-12-01

Post-glacial, coral-based climate records from the Western Pacific Warm Pool (WPWP), a region that serves as a major heat and moisture source to the ocean-atmosphere system, provide sub-annually resolved windows into climate variability on interannual to multi-decadal timescales from this climatologically significant region. Paleoclimate reconstructions based on fossil corals require that the skeletal geochemistry be unaffected by diagenesis and that secular changes in seawater chemistry be known. Global seawater \\delta18O variations can be constrained using knowledge of past variations in ice volume, whereas much less is known about global seawater Sr/Ca variations, if they occur in the post-glacial interval. Our paleoclimate reconstructions are based on monthly resolved \\delta18O and Sr/Ca records in fossil Porites corals from the Western Solomon Islands ( ˜8° S, ˜157° E; Tetepare and Rendova). Post-depositional alteration of our fossil coral samples is minimal based on mineralogic (XRD), petrographic (SEM) and geochemical criteria (preservation of modern marine initial \\delta234U values). Four of these fossil coral time series are of particular interest: 99RND (age, 7,992±42; ~45 years), 01T-B (age, 7,647±73; ~65 years), 01T-AQ (age, 10,208±44; ~30 years), and 99TET-B (age, 11,987±69; ~ 30 years). We apply a model that uses simultaneous variations in coral \\delta18O and Sr/Ca in combination with estimates of post-glacial changes in seawater chemistry to reconstruct mean climate state during the early Holocene and the Younger Dryas. Model results indicate that on average SSTs in the WPWP were within 1° C of modern and that surface waters were more saline than modern during each of the four time intervals during which our fossil corals grew.

McCall Glacier record of Arctic climate change: Interpreting a northern Alaska ice core with regional water isotopes

NASA Astrophysics Data System (ADS)

Klein, E. S.; Nolan, M.; McConnell, J.; Sigl, M.; Cherry, J.; Young, J.; Welker, J. M.

2016-01-01

We explored modern precipitation and ice core isotope ratios to better understand both modern and paleo climate in the Arctic. Paleoclimate reconstructions require an understanding of how modern synoptic climate influences proxies used in those reconstructions, such as water isotopes. Therefore we measured periodic precipitation samples at Toolik Lake Field Station (Toolik) in the northern foothills of the Brooks Range in the Alaskan Arctic to determine δ18O and δ2H. We applied this multi-decadal local precipitation δ18O/temperature regression to ∼65 years of McCall Glacier (also in the Brooks Range) ice core isotope measurements and found an increase in reconstructed temperatures over the late-20th and early-21st centuries. We also show that the McCall Glacier δ18O isotope record is negatively correlated with the winter bidecadal North Pacific Index (NPI) climate oscillation. McCall Glacier deuterium excess (d-excess, δ2H - 8*δ18O) values display a bidecadal periodicity coherent with the NPI and suggest shifts from more southwestern Bering Sea moisture sources with less sea ice (lower d-excess values) to more northern Arctic Ocean moisture sources with more sea ice (higher d-excess values). Northern ice covered Arctic Ocean McCall Glacier moisture sources are associated with weak Aleutian Low (AL) circulation patterns and the southern moisture sources with strong AL patterns. Ice core d-excess values significantly decrease over the record, coincident with warmer temperatures and a significant reduction in Alaska sea ice concentration, which suggests that ice free northern ocean waters are increasingly serving as terrestrial precipitation moisture sources; a concept recently proposed by modeling studies and also present in Greenland ice core d-excess values during previous transitions to warm periods. This study also shows the efficacy and importance of using ice cores from Arctic valley glaciers in paleoclimate reconstructions.

The guidance of visual search by shape features and shape configurations.

PubMed

McCants, Cody W; Berggren, Nick; Eimer, Martin

2018-03-01

Representations of target features (attentional templates) guide attentional object selection during visual search. In many search tasks, targets objects are defined not by a single feature but by the spatial configuration of their component shapes. We used electrophysiological markers of attentional selection processes to determine whether the guidance of shape configuration search is entirely part-based or sensitive to the spatial relationship between shape features. Participants searched for targets defined by the spatial arrangement of two shape components (e.g., hourglass above circle). N2pc components were triggered not only by targets but also by partially matching distractors with one target shape (e.g., hourglass above hexagon) and by distractors that contained both target shapes in the reverse arrangement (e.g., circle above hourglass), in line with part-based attentional control. Target N2pc components were delayed when a reverse distractor was present on the opposite side of the same display, suggesting that early shape-specific attentional guidance processes could not distinguish between targets and reverse distractors. The control of attention then became sensitive to spatial configuration, which resulted in a stronger attentional bias for target objects relative to reverse and partially matching distractors. Results demonstrate that search for target objects defined by the spatial arrangement of their component shapes is initially controlled in a feature-based fashion but can later be guided by templates for spatial configurations. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Code Mixing and Modernization across Cultures.

ERIC Educational Resources Information Center

Kamwangamalu, Nkonko M.

A review of recent studies addressed the functional uses of code mixing across cultures. Expressions of code mixing (CM) are not random; in fact, a number of functions of code mixing can easily be delineated, for example, the concept of "modernization.""Modernization" is viewed with respect to how bilingual code mixers perceive…

ShapeRotator: An R tool for standardized rigid rotations of articulated three-dimensional structures with application for geometric morphometrics.

PubMed

Vidal-García, Marta; Bandara, Lashi; Keogh, J Scott

2018-05-01

The quantification of complex morphological patterns typically involves comprehensive shape and size analyses, usually obtained by gathering morphological data from all the structures that capture the phenotypic diversity of an organism or object. Articulated structures are a critical component of overall phenotypic diversity, but data gathered from these structures are difficult to incorporate into modern analyses because of the complexities associated with jointly quantifying 3D shape in multiple structures. While there are existing methods for analyzing shape variation in articulated structures in two-dimensional (2D) space, these methods do not work in 3D, a rapidly growing area of capability and research. Here, we describe a simple geometric rigid rotation approach that removes the effect of random translation and rotation, enabling the morphological analysis of 3D articulated structures. Our method is based on Cartesian coordinates in 3D space, so it can be applied to any morphometric problem that also uses 3D coordinates (e.g., spherical harmonics). We demonstrate the method by applying it to a landmark-based dataset for analyzing shape variation using geometric morphometrics. We have developed an R tool (ShapeRotator) so that the method can be easily implemented in the commonly used R package geomorph and MorphoJ software. This method will be a valuable tool for 3D morphological analyses in articulated structures by allowing an exhaustive examination of shape and size diversity.

Fire, Ice and Water: Glaciologic, Paleoclimate and Anthropogenic Linkages During Past Mega-Droughts in the Uinta Mountains, Utah

NASA Astrophysics Data System (ADS)

Power, M. J.; Rupper, S.; Codding, B.; Schaefer, J.; Hess, M.

2017-12-01

Alpine glaciers provide a valuable water source during prolonged drought events. We explore whether long-term climate dynamics and associated glacier changes within mountain drainage basins and adjacent landscapes ultimately influence how prehistoric human populations choose settlement locations. The Uinta Mountains of Utah, with a steep present-day precipitation gradient from the lowlands to the alpine zone of 20-100 cm per year, has a rich glacial history related to natural and anthropogenic climate variability. Here we examine how past climate variability has impacted glaciers and ultimately the availability of water over long timescales, and how these changes affected human settlement and subsistence decisions. Through a combination of geomorphologic evidence, paleoclimate proxies, and glacier and climate modelling, we test the hypothesis that glacier-charged hydrologic systems buffer prehistoric populations during extreme drought periods, facilitating long-term landscape management with fire. Initial field surveys suggest middle- and low-elevation glacial valleys contain glacially-derived sediment from meltwater and resulted in terraced river channels and outwash plains visible today. These terraces provide estimates of river discharge during varying stages of glacier advance and retreat. Archaeological evidence from middle- and high-elevations in the Uinta Mountains suggests human populations persisted through periods of dramatic climate change, possibly linked to the persistence of glacially-derived water resources through drought periods. Paleoenvironmental records indicate a long history of fire driven by the combined interaction of climatic variation and human disturbance. This research highlights the important role of moisture variability determining human settlement patterns and landscape management throughout time, and has direct relevance to the impacts of anthropogenic precipitation and glacier changes on vulnerable populations in the coming century

Modernization of Management: Social and Socio-Cultural Aspects

ERIC Educational Resources Information Center

Vinogradova, Marina V.; Babakaev, Sergy V.; Larionova, Anna A.; Kobyak, Marina V.; Layko, Mikhail Y.

2016-01-01

The relevance of the topic is determined by the new challenges faced by the Russian state in modern conditions that have a significant impact on public administration, which entails the need for its comprehensive modernization. In this regard, this article is aimed at the disclosure of social and socio-cultural aspects of the modernization of…

The Modern Religious Language of Education: Rousseau's "Emile"

ERIC Educational Resources Information Center

Osterwalder, Fritz

2012-01-01

The Republican education, its concepts, theories, and form of discourse belong to the shared European heritage of the pre-modern Age. The pedagogy of humanism and its effects on the early Modern Age are represented by Republicanism. Even if Republicanism found a political continuation in liberalism and democratism of the Modern Age, the same…

The Relationship between Traditional Chinese Medicine and Modern Medicine

PubMed Central

2013-01-01

The essence of the traditional Chinese medicine has always been the most advanced and experienced therapeutic approach in the world. It has knowledge that can impact the direction of future modern medical development; still, it is easy to find simple knowledge with mark of times and special cultures. The basic structure of traditional Chinese medicine is composed of three parts: one consistent with modern medicine, one involuntarily beyond modern medicine, and one that needs to be further evaluated. The part that is consistent with modern medicine includes consensus on several theories and concepts of traditional Chinese medicine, and usage of several treatments and prescriptions of traditional Chinese medicine including commonly used Chinese herbs. The part that is involuntarily beyond modern medicine contains several advanced theories and important concepts of traditional Chinese medicine, relatively advanced treatments, formula and modern prescriptions, leading herbs, acupuncture treatment and acupuncture anesthesia of traditional Chinese medicine that affect modern medicine and incorporates massage treatment that has been gradually acknowledged by modern therapy. The part that needs to be further evaluated consists not only the knowledge of pulse diagnosis, prescription, and herbs, but also many other aspects of traditional Chinese medicine. PMID:23983772

Defective modernization and health in Mexico.

PubMed

Simonelli, J M

1987-01-01

This paper uses data gathered in a semi-arid, mountain region of the border state of Sonora, Mexico to illustrate that modernization and the importation of urban ideas and values can influence health status in unexpected ways. It traces the historic process of modernization in a rural municipio, relating this to social promises and economic cycles in Mexico. Modernization is seen to encompass life standard improvements and access to medical care; extension of road and transportation systems; and the widespread availability of information and education, as well as lifestyle changes required to incorporate these 'urban' influences. Reviewing the link between climate and health in arid lands, the paper notes that such modernization can be a well-meaning intrusion upon a set of cultural and social practices which had proved adaptive in dealing with climatic extremes. Initial modernization produces impressive declines in mortality and morbidity, as illustrated in an analysis of mortality figures and causes in relation to age cohorts and decades for the years 1955-1984. However, reductions in epidermic-related infant mortality are shown to be offset by increases in deaths due to trauma, chronic conditions and endemic disease. An analysis of morbidity for the year 1983-84 indicates that continuing high rates of infectious disease are related to conditions which result from increasingly defective modernization. To maintain technology, including water, electrical, and sewage systems, continual capital expenditure on both the public and private level is required. The economic crisis in Mexico is reducing available funds at a time when the community has adjusted its traditional lifestyle to incorporate technological improvements. In light of this, it is likely that inroads against infectious disease will not just continue to be stalemated, but could actually be reversed. This finding has implications for towns and villages on both sides of the Mexican-American border.

Online Learning for Classification of Alzheimer Disease based on Cortical Thickness and Hippocampal Shape Analysis.

PubMed

Lee, Ga-Young; Kim, Jeonghun; Kim, Ju Han; Kim, Kiwoong; Seong, Joon-Kyung

2014-01-01

Mobile healthcare applications are becoming a growing trend. Also, the prevalence of dementia in modern society is showing a steady growing trend. Among degenerative brain diseases that cause dementia, Alzheimer disease (AD) is the most common. The purpose of this study was to identify AD patients using magnetic resonance imaging in the mobile environment. We propose an incremental classification for mobile healthcare systems. Our classification method is based on incremental learning for AD diagnosis and AD prediction using the cortical thickness data and hippocampus shape. We constructed a classifier based on principal component analysis and linear discriminant analysis. We performed initial learning and mobile subject classification. Initial learning is the group learning part in our server. Our smartphone agent implements the mobile classification and shows various results. With use of cortical thickness data analysis alone, the discrimination accuracy was 87.33% (sensitivity 96.49% and specificity 64.33%). When cortical thickness data and hippocampal shape were analyzed together, the achieved accuracy was 87.52% (sensitivity 96.79% and specificity 63.24%). In this paper, we presented a classification method based on online learning for AD diagnosis by employing both cortical thickness data and hippocampal shape analysis data. Our method was implemented on smartphone devices and discriminated AD patients for normal group.

A 3D quantitative comparison of trapezium and trapezoid relative articular and nonarticular surface areas in modern humans and great apes.

PubMed

Tocheri, M W; Razdan, A; Williams, R C; Marzke, M W

2005-11-01

The structure and functions of the modern human hand are critical components of what distinguishes Homo sapiens from the great apes (Gorilla, Pan, and Pongo). In this study, attention is focused on the trapezium and trapezoid, the two most lateral bones of the distal carpal row, in the four extant hominid genera, representing the first time they have been quantified and analyzed together as a morphological-functional complex. Our objective is to quantify the relative articular and nonarticular surface areas of these two bones and to test whether modern humans exhibit significant shape differences from the great apes, as predicted by previous qualitative analyses and the functional demands of differing manipulative and locomotor strategies. Modern humans were predicted to show larger relative first metacarpal and scaphoid surfaces on the trapezium because of the regular recruitment of the thumb during manipulative behaviors; alternatively, great apes were predicted to show larger relative second metacarpal and scaphoid surfaces on the trapezoid because of the functional demands on the hands during locomotor behaviors. Modern humans were also expected to exhibit larger relative mutual joint surfaces between the trapezoid and adjacent carpals than do the great apes because of assumed transverse loads generated by the functional demands of the modern human power grip. Using 3D bone models acquired through laser digitizing, the relative articular and nonarticular areas on each bone are quantified and compared. Multivariate analyses of these data clearly distinguish modern humans from the great apes. In total, the observed differences between modern humans and the great apes support morphological predictions based on the fact that this region of the human wrist is no longer involved in weight-bearing during locomotor behavior and is instead recruited solely for manipulative behaviors. The results provide the beginnings of a 3D comparative standard against which further

Genomic and cranial phenotype data support multiple modern human dispersals from Africa and a southern route into Asia

PubMed Central

Reyes-Centeno, Hugo; Ghirotto, Silvia; Détroit, Florent; Grimaud-Hervé, Dominique; Barbujani, Guido; Harvati, Katerina

2014-01-01

Despite broad consensus on Africa as the main place of origin for anatomically modern humans, their dispersal pattern out of the continent continues to be intensely debated. In extant human populations, the observation of decreasing genetic and phenotypic diversity at increasing distances from sub-Saharan Africa has been interpreted as evidence for a single dispersal, accompanied by a series of founder effects. In such a scenario, modern human genetic and phenotypic variation was primarily generated through successive population bottlenecks and drift during a rapid worldwide expansion out of Africa in the Late Pleistocene. However, recent genetic studies, as well as accumulating archaeological and paleoanthropological evidence, challenge this parsimonious model. They suggest instead a “southern route” dispersal into Asia as early as the late Middle Pleistocene, followed by a separate dispersal into northern Eurasia. Here we test these competing out-of-Africa scenarios by modeling hypothetical geographical migration routes and assessing their correlation with neutral population differentiation, as measured by genetic polymorphisms and cranial shape variables of modern human populations from Africa and Asia. We show that both lines of evidence support a multiple-dispersals model in which Australo-Melanesian populations are relatively isolated descendants of an early dispersal, whereas other Asian populations are descended from, or highly admixed with, members of a subsequent migration event. PMID:24753576

A water-responsive shape memory ionomer with permanent shape reconfiguration ability

NASA Astrophysics Data System (ADS)

Bai, Yongkang; Zhang, Jiwen; Tian, Ran; Chen, Xin

2018-04-01

In this work, a water-responsive shape memory ionomer with high toughness was fabricated by cross-linking hyaluronic acid sodium (HAS) and polyvinyl alcohol (PVA) through coordination interactions. The strong Fe3+-carboxyl (from HAS) coordination interactions served as main physical cross-linking points for the performance of water-responsive shape memory, which associated with the flexibility of PVA chain producing excellent mechanical properties of this ionomer. The optimized ionomer was not only able to recover to its original shape within just 22 s by exposing to water, but exhibited high tensile strength up to 35.4 MPa and 4 times higher tractility than the ionomer without PVA. Moreover, the ionomers can be repeatedly programed to various new permanent shapes on demand due to the reversible physical interactions, which still performed complete and fast geometric recovery under stimuli even after 4 cycles of reprograming with 3 different shapes. The excellent shape memory and strong mechanical behaviors make our ionomers significant and promising smart materials for variety of applications.

Constructing a philosophy of chiropractic: evolving worldviews and modern foundation☆

PubMed Central

Senzon, Simon A.

2011-01-01

Objective The purpose of this article is to trace the foundations of DD Palmer's sense of self and philosophy of chiropractic to its sources in modern Western philosophy as well as current metatheories about modernity. Discussion DD Palmer's sense of self was indicative of a modern self. A modern self is characterized as a self that developed after the Western Enlightenment and must come to terms with the insights of modernity such as Cartesian dualism, Spinoza's substance, Rousseau's expressivism, and Kant's critiques. It is argued that Palmer's philosophy can be viewed as part of the this tradition alongside his involvement in the 19th century American metaphysical religious culture, which was itself a response to these challenges of the modern self of modernity. Conclusion Palmer's development of chiropractic and its philosophy was a reaction to the challenges and promises of modernity. PMID:22693479

Constructing a philosophy of chiropractic: evolving worldviews and modern foundation().

PubMed

Senzon, Simon A

2011-12-01

The purpose of this article is to trace the foundations of DD Palmer's sense of self and philosophy of chiropractic to its sources in modern Western philosophy as well as current metatheories about modernity. DD Palmer's sense of self was indicative of a modern self. A modern self is characterized as a self that developed after the Western Enlightenment and must come to terms with the insights of modernity such as Cartesian dualism, Spinoza's substance, Rousseau's expressivism, and Kant's critiques. It is argued that Palmer's philosophy can be viewed as part of the this tradition alongside his involvement in the 19th century American metaphysical religious culture, which was itself a response to these challenges of the modern self of modernity. Palmer's development of chiropractic and its philosophy was a reaction to the challenges and promises of modernity.

Electron line shape and transmission function of the KATRIN monitor spectrometer

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

Slezák, M.

Knowledge of the neutrino mass is of particular interest in modern neutrino physics. Besides the neutrinoless double beta decay and cosmological observation information about the neutrino mass is obtained from single beta decay by observing the shape of the electron spectrum near the endpoint. The KATRIN β decay experiment aims to push the limit on the effective electron antineutrino mass down to 0.2 eV/c{sup 2}. To reach this sensitivity several systematic effects have to be under control. One of them is the fluctuations of the absolute energy scale, which therefore has to be continuously monitored at very high precision. Thismore » paper shortly describes KATRIN, the technique for continuous monitoring of the absolute energy scale and recent improvements in analysis of the monitoring data.« less

Shaping off-axis metallic membrane reflectors using optimal boundary shapes and inelastic strains

NASA Technical Reports Server (NTRS)

White, C. V.; Dragovan, M.

2004-01-01

This paper will describe a novel concept for constructing off-axis membrane reflector surfaces. Membrane reflectors have been extensively studied, including investigations into inflated lenticular architectures, shaping by spin casting, shaping using electrostatic forces, and shaping by evacuating behind a membrane surface stretched between circular or annular-shaped supports.

Manual: Modern Gum Naval Stores Methods

Treesearch

Ralph W. Clements

1974-01-01

Modern gum naval stores methods have been developed to benefit both the gum producer and the timber owner. Following the methods described in this booklet will bring maximum gum yields, whill reduce chipping-labor requirements about 50 percent, and will make the worked-out tree saleable for other wood products. If these modern turpentining mehods are used, naval...

Modern Dilemmas - Science (World History Series).

ERIC Educational Resources Information Center

Montgomery County Public Schools, Rockville, MD.

The publication, referred to as a unit on "Modern Dilemmas," was completed in 1969 and is part of a Modern World History pilot project integrating areas of art, literature, philosophy, and science into the social studies curriculum. The unit seeks to explore all of the facets of science as part of man's search for meaning, but because of time…

Femoral vessel injuries in modern warfare since Vietnam.

PubMed

Pearl, Jonathan P; McNally, Michael P; Perdue, Philip W

2003-09-01

The incidence of lower extremity injuries is high in modern warfare; however the mortality rate from these injuries is low. Despite the overall low mortality of lower extremity injuries, many deaths in modern conflicts are due to femoral vessel injury. The modern warfare literature was reviewed. In Somalia, 1 of the 14 reported deaths was due to a laceration of the superficial femoral artery. In the Persian Gulf, three deaths were reported in an Army field hospital, one resulted from uncontrolled hemorrhage from a profunda femoris artery wound and two others resulted from traumatic amputations with consequent major arterial injury. Despite the advances in modern body armor, the groin is left unprotected. A strategy to help minimize U.S. casualties in modern warfare may be a method of field hemostasis specifically designed for femoral vessel injury.

Genetic evidence and the modern human origins debate.

PubMed

Relethford, J H

2008-06-01

A continued debate in anthropology concerns the evolutionary origin of 'anatomically modern humans' (Homo sapiens sapiens). Different models have been proposed to examine the related questions of (1) where and when anatomically modern humans first appeared and (2) the genetic and evolutionary relationship between modern humans and earlier human populations. Genetic data have been increasingly used to address these questions. Genetic data on living human populations have been used to reconstruct the evolutionary history of the human species by considering how global patterns of human variation could be produced given different evolutionary scenarios. Of particular interest are gene trees that reconstruct the time and place of the most recent common ancestor of humanity for a given haplotype and the analysis of regional differences in genetic diversity. Ancient DNA has also allowed a direct assessment of genetic variation in European Neandertals. Together with the fossil record, genetic data provide insight into the origin of modern humans. The evidence points to an African origin of modern humans dating back to 200,000 years followed by later expansions of moderns out of Africa across the Old World. What is less clear is what happened when these early modern humans met preexisting 'archaic human' populations outside of Africa. At present, it is difficult to distinguish between a model of total genetic replacement and a model that includes some degree of genetic mixture.

Active shape control of composite blades using shape memory actuation

NASA Astrophysics Data System (ADS)

Chandra, Ramesh

2001-10-01

This paper presents active shape control of composite beams using shape memory actuation. Shape memory alloy (SMA) bender elements trained to memorize bending shape were used to induce bending and twisting deformations in composite beams. Bending-torsion coupled graphite-epoxy and kevlar-epoxy composite beams with Teflon inserts were manufactured using an autoclave-molding technique. Teflon inserts were replaced by trained SMA bender elements. Composite beams with SMA bender elements were activated by heating these using electrical resistive heating and the bending and twisting deformations of the beams were measured using a mirror and laser system. The structural response of the composite beams activated by SMA elements was predicted using the Vlasov theory, where these beams were modeled as open sections with many branches. The bending moment induced by a SMA bender element was calculated from its experimentally determined memorized shape. The bending, torsion, and bending-torsion coupling stiffness coefficients of these beams were obtained using analytical formulation of an open-section composite beam with many branches (Vlasov theory).

Rail Modernization Study

DOT National Transportation Integrated Search

1987-04-01

This study summarizes the results of a multi-year assessment of the rail transit and commuter rail systems. The work was based on an earlier study design effort. The purposes of the study were to determine the costs of upgrading and modernizing urban...

CFD Sensitivity Analysis of a Modern Civil Transport Near Buffet-Onset Conditions

NASA Technical Reports Server (NTRS)

Rumsey, Christopher L.; Allison, Dennis O.; Biedron, Robert T.; Buning, Pieter G.; Gainer, Thomas G.; Morrison, Joseph H.; Rivers, S. Melissa; Mysko, Stephen J.; Witkowski, David P.

2001-01-01

A computational fluid dynamics (CFD) sensitivity analysis is conducted for a modern civil transport at several conditions ranging from mostly attached flow to flow with substantial separation. Two different Navier-Stokes computer codes and four different turbulence models are utilized, and results are compared both to wind tunnel data at flight Reynolds number and flight data. In-depth CFD sensitivities to grid, code, spatial differencing method, aeroelastic shape, and turbulence model are described for conditions near buffet onset (a condition at which significant separation exists). In summary, given a grid of sufficient density for a given aeroelastic wing shape, the combined approximate error band in CFD at conditions near buffet onset due to code, spatial differencing method, and turbulence model is: 6% in lift, 7% in drag, and 16% in moment. The biggest two contributers to this uncertainty are turbulence model and code. Computed results agree well with wind tunnel surface pressure measurements both for an overspeed 'cruise' case as well as a case with small trailing edge separation. At and beyond buffet onset, computed results agree well over the inner half of the wing, but shock location is predicted too far aft at some of the outboard stations. Lift, drag, and moment curves are predicted in good agreement with experimental results from the wind tunnel.

The facts that the physical-chemical properties of modern tablets distinguish them from natural food lumps

NASA Astrophysics Data System (ADS)

Urakov, A.; Urakova, N.; Reshetnikov, A.; Kopylov, M.; Kasatkin, A.; Baymurzin, D.; Gabdrafikov, R.

2017-02-01

It was found that pharmaceutical companies produce drugs in tablet form, physical or physical-chemical properties that are radically different from those of the properties of natural food lumps, in that adult converts food in our mouth before swallowing. It was shown that the conventional shape, color, size, volume, specific gravity, hardness, osmotic and acid activity of modern tablets impair the physical and physicochemical properties of the liquid contents of the stomach is much stronger than such “building” materials, such as chalk, clay, sand, river pebbles and gravel. The results showed, that the value of the specific hardness, deforming tablets, can distinguish modern tablets from each other by more than 5000 times. Therefore, introduction tablets inside without information of ability injuring their action leads to the fact that soft and “unsalted” tablets almost nothing damage, and too “salty” and solid tablets damage the gums, lips, tongue, teeth and dental structures. To reduce the traumatic action tablets offered standardize osmoticity, corrosion and hardness within the range of safe values for soft and hard tissues of the oral cavity and improve standard introduction of tablets in the mouth.

Beck, Asia and second modernity.

PubMed

Calhoun, Craig

2010-09-01

The work of Ulrich Beck has been important in bringing sociological attention to the ways issues of risk are embedded in contemporary globalization, in developing a theory of 'reflexive modernization', and in calling for social science to transcend 'methodological nationalism'. In recent studies, he and his colleagues help to correct for the Western bias of many accounts of cosmopolitanism and reflexive modernization, and seek to distinguish normative goals from empirical analysis. In this paper I argue that further clarification of this latter distinction is needed but hard to reach within a framework that still embeds the normative account in the idea that empirical change has a clear direction. Similar issues beset the presentation of diverse patterns in recent history as all variants of 'second modernity'. Lastly, I note that ironically, given the declared 'methodological cosmopolitanism' of the authors, the empirical studies here all focus on national cases. © London School of Economics and Political Science 2010.

The First Modern Human Dispersals across Africa

PubMed Central

Rito, Teresa; Richards, Martin B.; Fernandes, Verónica; Alshamali, Farida; Cerny, Viktor

2013-01-01

The emergence of more refined chronologies for climate change and archaeology in prehistoric Africa, and for the evolution of human mitochondrial DNA (mtDNA), now make it feasible to test more sophisticated models of early modern human dispersals suggested by mtDNA distributions. Here we have generated 42 novel whole-mtDNA genomes belonging to haplogroup L0, the most divergent clade in the maternal line of descent, and analysed them alongside the growing database of African lineages belonging to L0’s sister clade, L1’6. We propose that the last common ancestor of modern human mtDNAs (carried by “mitochondrial Eve”) possibly arose in central Africa ~180 ka, at a time of low population size. By ~130 ka two distinct groups of anatomically modern humans co-existed in Africa: broadly, the ancestors of many modern-day Khoe and San populations in the south and a second central/eastern African group that includes the ancestors of most extant worldwide populations. Early modern human dispersals correlate with climate changes, particularly the tropical African “megadroughts” of MIS 5 (marine isotope stage 5, 135–75 ka) which paradoxically may have facilitated expansions in central and eastern Africa, ultimately triggering the dispersal out of Africa of people carrying haplogroup L3 ~60 ka. Two south to east migrations are discernible within haplogroup LO. One, between 120 and 75 ka, represents the first unambiguous long-range modern human dispersal detected by mtDNA and might have allowed the dispersal of several markers of modernity. A second one, within the last 20 ka signalled by L0d, may have been responsible for the spread of southern click-consonant languages to eastern Africa, contrary to the view that these eastern examples constitute relicts of an ancient, much wider distribution. PMID:24236171

Grid Modernization Laboratory Consortium - Testing and Verification

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

Kroposki, Benjamin; Skare, Paul; Pratt, Rob

This paper highlights some of the unique testing capabilities and projects being performed at several national laboratories as part of the U. S. Department of Energy Grid Modernization Laboratory Consortium. As part of this effort, the Grid Modernization Laboratory Consortium Testing Network isbeing developed to accelerate grid modernization by enablingaccess to a comprehensive testing infrastructure and creating a repository of validated models and simulation tools that will be publicly available. This work is key to accelerating thedevelopment, validation, standardization, adoption, and deployment of new grid technologies to help meet U. S. energy goals.

Morphology and function of Neandertal and modern human ear ossicles

PubMed Central

David, Romain; Gunz, Philipp; Schmidt, Tobias; Spoor, Fred; Hublin, Jean-Jacques

2016-01-01

The diminutive middle ear ossicles (malleus, incus, stapes) housed in the tympanic cavity of the temporal bone play an important role in audition. The few known ossicles of Neandertals are distinctly different from those of anatomically modern humans (AMHs), despite the close relationship between both human species. Although not mutually exclusive, these differences may affect hearing capacity or could reflect covariation with the surrounding temporal bone. Until now, detailed comparisons were hampered by the small sample of Neandertal ossicles and the unavailability of methods combining analyses of ossicles with surrounding structures. Here, we present an analysis of the largest sample of Neandertal ossicles to date, including many previously unknown specimens, covering a wide geographic and temporal range. Microcomputed tomography scans and 3D geometric morphometrics were used to quantify shape and functional properties of the ossicles and the tympanic cavity and make comparisons with recent and extinct AMHs as well as African apes. We find striking morphological differences between ossicles of AMHs and Neandertals. Ossicles of both Neandertals and AMHs appear derived compared with the inferred ancestral morphology, albeit in different ways. Brain size increase evolved separately in AMHs and Neandertals, leading to differences in the tympanic cavity and, consequently, the shape and spatial configuration of the ossicles. Despite these different evolutionary trajectories, functional properties of the middle ear of AMHs and Neandertals are largely similar. The relevance of these functionally equivalent solutions is likely to conserve a similar auditory sensitivity level inherited from their last common ancestor. PMID:27671643

Subjectively Interpreted Shape Dimensions as Privileged and Orthogonal Axes in Mental Shape Space

ERIC Educational Resources Information Center

Ons, Bart; De Baene, Wouter; Wagemans, Johan

2011-01-01

The shape of an object is fundamental in object recognition but it is still an open issue to what extent shape differences are perceived analytically (i.e., by the dimensional structure of the shapes) or holistically (i.e., by the overall similarity of the shapes). The dimensional structure of a stimulus is available in a primary stage of…

Visual shape perception as Bayesian inference of 3D object-centered shape representations.

PubMed

Erdogan, Goker; Jacobs, Robert A

2017-11-01

Despite decades of research, little is known about how people visually perceive object shape. We hypothesize that a promising approach to shape perception is provided by a "visual perception as Bayesian inference" framework which augments an emphasis on visual representation with an emphasis on the idea that shape perception is a form of statistical inference. Our hypothesis claims that shape perception of unfamiliar objects can be characterized as statistical inference of 3D shape in an object-centered coordinate system. We describe a computational model based on our theoretical framework, and provide evidence for the model along two lines. First, we show that, counterintuitively, the model accounts for viewpoint-dependency of object recognition, traditionally regarded as evidence against people's use of 3D object-centered shape representations. Second, we report the results of an experiment using a shape similarity task, and present an extensive evaluation of existing models' abilities to account for the experimental data. We find that our shape inference model captures subjects' behaviors better than competing models. Taken as a whole, our experimental and computational results illustrate the promise of our approach and suggest that people's shape representations of unfamiliar objects are probabilistic, 3D, and object-centered. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The evolution of body size and shape in the human career

PubMed Central

Grabowski, Mark; Hatala, Kevin G.; Richmond, Brian G.

2016-01-01

Body size is a fundamental biological property of organisms, and documenting body size variation in hominin evolution is an important goal of palaeoanthropology. Estimating body mass appears deceptively simple but is laden with theoretical and pragmatic assumptions about best predictors and the most appropriate reference samples. Modern human training samples with known masses are arguably the ‘best’ for estimating size in early bipedal hominins such as the australopiths and all members of the genus Homo, but it is not clear if they are the most appropriate priors for reconstructing the size of the earliest putative hominins such as Orrorin and Ardipithecus. The trajectory of body size evolution in the early part of the human career is reviewed here and found to be complex and nonlinear. Australopith body size varies enormously across both space and time. The pre-erectus early Homo fossil record from Africa is poor and dominated by relatively small-bodied individuals, implying that the emergence of the genus Homo is probably not linked to an increase in body size or unprecedented increases in size variation. Body size differences alone cannot explain the observed variation in hominin body shape, especially when examined in the context of small fossil hominins and pygmy modern humans. This article is part of the themed issue ‘Major transitions in human evolution’. PMID:27298459

The evolution of body size and shape in the human career.

PubMed

Jungers, William L; Grabowski, Mark; Hatala, Kevin G; Richmond, Brian G

2016-07-05

Body size is a fundamental biological property of organisms, and documenting body size variation in hominin evolution is an important goal of palaeoanthropology. Estimating body mass appears deceptively simple but is laden with theoretical and pragmatic assumptions about best predictors and the most appropriate reference samples. Modern human training samples with known masses are arguably the 'best' for estimating size in early bipedal hominins such as the australopiths and all members of the genus Homo, but it is not clear if they are the most appropriate priors for reconstructing the size of the earliest putative hominins such as Orrorin and Ardipithecus The trajectory of body size evolution in the early part of the human career is reviewed here and found to be complex and nonlinear. Australopith body size varies enormously across both space and time. The pre-erectus early Homo fossil record from Africa is poor and dominated by relatively small-bodied individuals, implying that the emergence of the genus Homo is probably not linked to an increase in body size or unprecedented increases in size variation. Body size differences alone cannot explain the observed variation in hominin body shape, especially when examined in the context of small fossil hominins and pygmy modern humans.This article is part of the themed issue 'Major transitions in human evolution'. © 2016 The Author(s).

Telling Modernization: Three Voices. Life History, Gender and the Discourse of Modernization. Roskilde University Life History Project Paper.

ERIC Educational Resources Information Center

Anderson, Linda

The relationship between life history, gender, and the discourse of modernization was examined from the perspective of a researcher with extensive experience performing evaluations about modernization within human services in Denmark. Three stories about site-based management in two human service institutionsa youth center and a boarding school…

The Newtonian Moment - Isaac Newton and the Making of Modern Culture

NASA Astrophysics Data System (ADS)

Feingold, Mordechai

2004-12-01

Isaac Newton is a legendary figure whose mythical dimension threatens to overshadow the actual man. The story of the apple falling from the tree may or may not be true, but Isaac Newton's revolutionary discoveries and their importance to the Enlightenment era and beyond are undeniable. The Newtonian Moment , a companion volume to a forthcoming exhibition by the New York Public Library, investigates the effect that Newton's theories and discoveries had, not only on the growth of science, but also on the very shape of modern culture and thought. Newton's scientific work at Cambridge was groundbreaking. From his optical experiments with prisms during the 1660s to the publication of both Principia (1687) and Opticks (1704), Newton's achievements were widely disseminated, inciting tremendous interest and excitement. Newtonianism developed into a worldview marked by many tensions: between modernity and the old guard, between the humanities and science, and the public battles between great minds. The Newtonian Moment illuminates the many facets of his colossal accomplishments, as well as the debates over the kind of knowledge that his accomplishments engendered. The book contributes to a greater understanding of the world today by offering a panoramic view of the profound impact of Newtonianism on the science, literature, art, and religion of the Enlightenment. Copiously illustrated with items drawn from the collections of the New York Public Library as well as numerous other libraries and museums, The Newtonian Moment enlightens its audience with a guided and in-depth look at the man, his world, and his enduring legacy.

Transient coupling relationships of the Holocene Australian monsoon

NASA Astrophysics Data System (ADS)

McRobie, F. H.; Stemler, T.; Wyrwoll, K.-H.

2015-08-01

The northwest Australian summer monsoon owes a notable degree of its interannual variability to interactions with other regional monsoon systems. Therefore, changes in the nature of these relationships may contribute to variability in monsoon strength over longer time scales. Previous attempts to evaluate how proxy records from the Indonesian-Australian monsoon region correspond to other records from the Indian and East Asian monsoon regions, as well as to El Niño-related proxy records, have been qualitative, relying on 'curve-fitting' methods. Here, we seek a quantitative approach for identifying coupling relationships between paleoclimate proxy records, employing statistical techniques to compute the interdependence of two paleoclimate time series. We verify the use of complex networks to identify coupling relationships between modern climate indices. This method is then extended to a set of paleoclimate proxy records from the Asian, Australasian and South American regions spanning the past 9000 years. The resulting networks demonstrate the existence of coupling relationships between regional monsoon systems on millennial time scales, but also highlight the transient nature of teleconnections during this period. In the context of the northwest Australian summer monsoon, we recognise a shift in coupling relationships from strong interhemispheric links with East Asian and ITCZ-related proxy records in the mid-Holocene to significantly weaker coupling in the later Holocene. Although the identified links cannot explain the underlying physical processes leading to coupling between regional monsoon systems, this method provides a step towards understanding the role that changes in teleconnections play in millennial-to orbital-scale climate variability.

Shape memory polymer medical device

DOEpatents

Maitland, Duncan [Pleasant Hill, CA; Benett, William J [Livermore, CA; Bearinger, Jane P [Livermore, CA; Wilson, Thomas S [San Leandro, CA; Small, IV, Ward; Schumann, Daniel L [Concord, CA; Jensen, Wayne A [Livermore, CA; Ortega, Jason M [Pacifica, CA; Marion, III, John E.; Loge, Jeffrey M [Stockton, CA

2010-06-29

A system for removing matter from a conduit. The system includes the steps of passing a transport vehicle and a shape memory polymer material through the conduit, transmitting energy to the shape memory polymer material for moving the shape memory polymer material from a first shape to a second and different shape, and withdrawing the transport vehicle and the shape memory polymer material through the conduit carrying the matter.

Alternative Shapes and Shaping Techniques for Enhanced Transformer Ratios in Beam Driven Techniques

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

Lemery, F.; Piot, P.

The transformer ration of collinear beam-driven techniques can be significantly improved by shaping the current profile of the drive bunch. To date, several current shapes have been proposed to increase the transformer ratio and produce quasi-uniform energy loss within the drive bunch. Some of these tailoring techniques are possible as a results of recent beam-dynamics advances, e.g., transverse-to-longitudinal emittance exchanger. In ths paper, we propose an alternative class of longitudinal shapes that enable high transformer ratio and uniform energy loss across the drive bunch. We also suggest a simple method based on photocathode-laser shaping and passive shaping in wakefield structuremore » to realize shape close to the theoretically optimized current profiles.« less

A New Method of Obtaining High-Resolution Paleoclimate Records from Speleothem Fluid Inclusions

NASA Astrophysics Data System (ADS)

Logan, A. J.; Horton, T. W.

2010-12-01

a minimum quantity of ~100nL water was required. In contrast to liquid water analyses, carbonate inclusion waters gave highly variable results. As plenty of signal was produced from relatively small sample sizes (~20 mg), the observed isotopic variation most likely reflects fractionation during fluid extraction, or natural isotopic variability. Additional tests and modifications to the extraction procedure are in progress, using a recently collected New Zealand stalagmite from a West Coast cave (DOC collection permit WC-27462-GEO). U-Th age data will accompany a paleoclimate record from this stalagmite obtained using standard carbonate analytical techniques, and compared to the results from our new fluid inclusion analyses.

Paleoclimate signals and age distributions from 41 public water works in the Netherlands

NASA Astrophysics Data System (ADS)

Broers, Hans Peter; de Weert, Jasperien; Sueltenfuss, Juergen; Aeschbach-Hertig, Werner; Vonhof, Hubert; Casteleijns, Jeroen

2015-04-01

fields with an age distribution skewed towards older ages are in the Roer Valley Graben structure, where fluvial and marine aquitards provide protection from recent recharge. Especially waters from this graben structure exhibit clear paleoclimate signals, with a clear relations between NGT (ranging from 2,8 -9 °C), 4He (up to 3.3E-6 cc STP/g) and 18O (range from -8.5 -- 5.5‰).

Paleohydrology of Late Quaternary floods in the Atacama Desert and their paleoclimate implications

NASA Astrophysics Data System (ADS)

Izquierdo, Tatiana; Abad, Manuel; Larrondo, Lidisy

2017-04-01

The Quaternary fluvial succession in the Copiapó Valley (northern Chile) have not been deeply studied even though they record a large amount of palaeoenvironmental and paleoclimate information in an area of great interest as the Atacama Desert. The city of Copiapó is located at the confluence between Quebrada Paipote (the most important tributary of the middle course) and Copiapó River which has been dry during the last decades due to the surface and groundwater exploitation for agricultural and mining activity purposes upstream. Despite that, historical chronicles describe numerous flooding events in the city during the last 400 years due to snowmelt during the summer months or unusually intense rains during any time of the year. The most recent event occurred on March 25, 2015 when 70% of the city flooded and more than 2.2 million m3 of sediment accumulated, mostly coming from Quebrada Paipote. The sedimentological analysis of the lower fluvial terrace of the Copiapó River has allowed us to identify a fluvial system that abruptly changes upward to paleoflood and aeolian deposits. The latter constitute the top of the lower fluvial terraces on which the city of Copiapó is built. The fluvial facies are mainly formed by imbricated to massive conglomerates and poorly sorted pebble and cobble sized conglomerates with laminated sandstones that probably were deposited in a braided gravel-bed river. The overlying deposits are constituted by several levels of massive sandy siltstones and well sorted fine sands of aeolian origin that are interpreted as overbank flood events linked to flooding episodes that alternate with long episodes of eolian dunes and sand sheets development that buried almost the entire alluvial plain. This sharp change in the facies association record an abrupt climate change in the southern Atacama Desert during the recent Quaternary towards more arid conditions, with a dominance of floods and aeolian morphogenesis over the typical fluvial system

Modern NMR Spectroscopy.

ERIC Educational Resources Information Center

Jelinski, Lynn W.

1984-01-01

Discusses direct chemical information that can be obtained from modern nuclear magnetic resonance (NMR) methods, concentrating on the types of problems that can be solved. Shows how selected methods provide information about polymers, bipolymers, biochemistry, small organic molecules, inorganic compounds, and compounds oriented in a magnetic…

Modern vs. Traditional.

ERIC Educational Resources Information Center

Zhenhui, Rao

1999-01-01

This article discusses traditional methods, such as the grammar-translation, and modern methods, the communicative approach, for teaching English-as-a-foreign-language in China. The relationship between linguistic accuracy and communicative competence, student-centered orientation, and the role of the teacher are highlighted. (Author/VWL)

Tooth - abnormal shape

MedlinePlus

Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

Modernizing engine displays

NASA Technical Reports Server (NTRS)

Schneider, E. T.; Enevoldson, E. K.

1984-01-01

The introduction of electronic fuel control to modern turbine engines has a number of advantages, which are related to an increase in engine performance and to a reduction or elimination of the problems associated with high angle of attack engine operation from the surface to 50,000 feet. If the appropriate engine display devices are available to the pilot, the fuel control system can provide a great amount of information. Some of the wealth of information available from modern fuel controls are discussed in this paper. The considered electronic engine control systems in their most recent forms are known as the Full Authority Digital Engine Control (FADEC) and the Digital Electronic Engine Control (DEEC). Attention is given to some details regarding the control systems, typical engine problems, the solution of problems with the aid of displays, engine displays in normal operation, an example display format, a multipage format, flight strategies, and hardware considerations.

Radiologic Professionalism in Modern Health Care.

PubMed

Hryhorczuk, Anastasia L; Hanneman, Kate; Eisenberg, Ronald L; Meyer, Elaine C; Brown, Stephen D

2015-10-01

Modern radiology is at the forefront of technological progress in medicine, a position that often places unique challenges on its professional character. This article uses "Medical Professionalism in the New Millennium: A Physician Charter," a document published in 2002 and endorsed by several major radiology organizations, as a lens for exploring professional challenges in modern radiology. The three main tenets of the Charter emphasize patient welfare, patient autonomy, and the reduction of disparities in health care distribution. This article reviews the ways in which modern technology and financial structures potentially create stressors on professionalism in radiology, while highlighting the opportunities they provide for radiologists seeking to fulfill the professional goals articulated in the Charter. Picture archiving and communication systems (PACS) and voice recognition systems have transformed the speed of radiology and enhanced the ability of radiologists to improve patient care but also have brought new tensions to the workplace. Although teleradiology may improve global access to radiologists, it may also promote the commoditization of radiology, which diminishes the professional stature of radiologists. Social media and patient portals provide radiologists with new forums for interacting with the public and patients, potentially promoting patient welfare. However, patient privacy and autonomy are important considerations. Finally, modern financial structures provide radiologists with both entrepreneurial opportunities as well as the temptation for unprofessional conduct. Each of these advances carries the potential for professional growth while testing the professional stature of radiology. By considering the risks and benefits of emerging technologies in the modern radiology world, radiologists can chart an ethical and professional future path. © RSNA, 2015.

Shear Capacity of C-Shaped and L-Shaped Angle Shear Connectors.

PubMed

Tahmasbi, Farzad; Maleki, Shervin; Shariati, Mahdi; Ramli Sulong, N H; Tahir, M M

2016-01-01

This paper investigates the behaviour of C-shaped and L-shaped angle shear connectors embedded in solid concrete slabs. An effective finite element model is proposed to simulate the push out tests of these shear connectors that encompass nonlinear material behaviour, large displacement and damage plasticity. The finite element models are validated against test results. Parametric studies using this nonlinear model are performed to investigate the variations in concrete strength and connector dimensions. The finite element analyses also confirm the test results that increasing the length of shear connector increases their shear strength proportionately. It is observed that the maximum stress in L-shaped angle connectors takes place in the weld attachment to the beam, whereas in the C-shaped angle connectors, it is in the attached leg. The location of maximum concrete compressive damage is rendered in each case. Finally, a new equation for prediction of the shear capacity of C-shaped angle connectors is proposed.

Shear Capacity of C-Shaped and L-Shaped Angle Shear Connectors

PubMed Central

Tahmasbi, Farzad; Maleki, Shervin; Shariati, Mahdi; Ramli Sulong, N. H.; Tahir, M. M.

2016-01-01

This paper investigates the behaviour of C-shaped and L-shaped angle shear connectors embedded in solid concrete slabs. An effective finite element model is proposed to simulate the push out tests of these shear connectors that encompass nonlinear material behaviour, large displacement and damage plasticity. The finite element models are validated against test results. Parametric studies using this nonlinear model are performed to investigate the variations in concrete strength and connector dimensions. The finite element analyses also confirm the test results that increasing the length of shear connector increases their shear strength proportionately. It is observed that the maximum stress in L-shaped angle connectors takes place in the weld attachment to the beam, whereas in the C-shaped angle connectors, it is in the attached leg. The location of maximum concrete compressive damage is rendered in each case. Finally, a new equation for prediction of the shear capacity of C-shaped angle connectors is proposed. PMID:27478894

Early Pleistocene third metacarpal from Kenya and the evolution of modern human-like hand morphology

PubMed Central

Ward, Carol V.; Tocheri, Matthew W.; Plavcan, J. Michael; Brown, Francis H.; Manthi, Fredrick Kyalo

2014-01-01

Despite discoveries of relatively complete hands from two early hominin species (Ardipithecus ramidus and Australopithecus sediba) and partial hands from another (Australopithecus afarensis), fundamental questions remain about the evolution of human-like hand anatomy and function. These questions are driven by the paucity of hand fossils in the hominin fossil record between 800,000 and 1.8 My old, a time interval well documented for the emergence and subsequent proliferation of Acheulian technology (shaped bifacial stone tools). Modern and Middle to Late Pleistocene humans share a suite of derived features in the thumb, wrist, and radial carpometacarpal joints that is noticeably absent in early hominins. Here we show that one of the most distinctive features of this suite in the Middle Pleistocene to recent human hand, the third metacarpal styloid process, was present ∼1.42 Mya in an East African hominin from Kaitio, West Turkana, Kenya. This fossil thus provides the earliest unambiguous evidence for the evolution of a key shared derived characteristic of modern human and Neandertal hand morphology and suggests that the distinctive complex of radial carpometacarpal joint features in the human hand arose early in the evolution of the genus Homo and probably in Homo erectus sensu lato. PMID:24344276

The bivalve Glycymeris planicostalis as a high-resolution paleoclimate archive for the Rupelian (Early Oligocene) of central Europe

NASA Astrophysics Data System (ADS)

Walliser, E. O.; Schöne, B. R.; Tütken, T.; Zirkel, J.; Grimm, K. I.; Pross, J.

2015-04-01

Current global warming is likely to result in a unipolar glaciated world with unpredictable repercussions on atmospheric and oceanic circulation patterns. These changes are expected to affect seasonal extremes and the year-to-year variability of seasonality. To better constrain the mode and tempo of the anticipated changes, climatologists require ultra-high-resolution proxy data of time intervals in the past, e.g., the Oligocene, during which boundary conditions were similar to those predicted for the near future. In the present paper, we assess whether such information can be obtained from shells of the long-lived bivalve mollusk Glycymeris planicostalis from the late Rupelian of the Mainz Basin, Germany. Our results indicate that the studied shells are pristinely preserved and provide an excellent archive for reconstructing changes of sea surface temperature on seasonal to interannual timescales. Shells of G. planicostalis grew uninterruptedly during winter and summer and therefore recorded the full seasonal temperature amplitude that prevailed in the Mainz Basin ~ 30 Ma. Absolute sea surface temperature data were reconstructed from δ18Oshell values assuming a δ18Owater signature that was extrapolated from coeval sirenian tooth enamel. Reconstructed values range between 12.3 and 22.0 °C and agree well with previous estimates based on planktonic foraminifera and shark teeth. However, temperatures during seasonal extremes vary greatly on interannual timescales. Mathematically re-sampled (i.e., corrected for uneven number of samples per annual increment) winter and summer temperatures averaged over 40 annual increments of three specimens equal 13.6 ± 0.8 and 17.3 ± 1.2 °C, respectively. Such high-resolution paleoclimate information can be highly relevant for numerical climate studies aiming to predict possible future climates in a unipolar glaciated or, ultimately, polar-ice-free world.

Transform Modern Language Learning through Mobile Devices

ERIC Educational Resources Information Center

Tuttle, Harry Grover

2013-01-01

College professors can transform their modern language classes through mobile devices. Their students' learning becomes more active, more personalized, more contextual, and more culturally authentic as illustrated through the author's modern language mobile learning classroom examples. In addition, their students engage in many diverse types of…

Casebooks in early modern England: medicine, astrology, and written records.

PubMed

Kassell, Lauren

2014-01-01

Casebooks are the richest sources that we have for encounters between early modern medical practitioners and their patients. This article compares astrological and medical records across two centuries, focused on England, and charts developments in the ways in which practitioners kept records and reflected on their practices. Astrologers had a long history of working from particular moments, stellar configurations, and events to general rules. These practices required systematic notation. Physicians increasingly modeled themselves on Hippocrates, recording details of cases as the basis for reasoned expositions of the histories of disease. Medical records, as other scholars have demonstrated, shaped the production of medical knowledge. Instead, this article focuses on the nature of casebooks as artifacts of the medical encounter. It establishes that casebooks were serial records of practice, akin to diaries, testimonials, and registers; identifies extant English casebooks and the practices that led to their production and preservation; and concludes that the processes of writing, ordering, and preserving medical records are as important for understanding the medical encounter as the records themselves.

Sex determination by three-dimensional geometric morphometrics of the vault and midsagittal curve of the neurocranium in a modern Greek population sample.

PubMed

Chovalopoulou, Maria-Eleni; Valakos, Efstratios D; Manolis, Sotiris K

2016-06-01

The aim of this study is to assess sexual dimorphism of adult crania in the vault and midsagittal curve of the vault using three-dimensional geometric morphometric methods. The study sample consisted of 176 crania of known sex (94 males, 82 females) belonging to individuals who lived during the 20th century in Greece. The three-dimensional co-ordinates of 31 ecto-cranial landmarks and 30 semi-landmarks were digitized using a MicroScribe 3DX contact digitizer. Generalized Procrustes analysis (GPA) was used to obtain size and shape variables for statistical analysis. Shape, size and form analyses were carried out by logistic regression and three discriminant function analyses. Results indicate that there are shape differences between sexes. Females in the region of the parietal bones are narrower and the axis forming the frontal and occipital bones is more elongated; the frontal bone is more vertical. Sex-specific shape differences give better classification results in the vault (79%) compared with the midsagittal curve of the neurocranium (68.8%). Size alone yielded better results for cranial vault (82%), while for the midsagittal curve of the vault the result is poorer (68.1%). As anticipated, the classification accuracy improves when both size and shape are combined (89.2% for vault, and 79.4% for midsagittal curve of the vault). These latter findings imply that, in contrast to the midsagittal curve of the neurocranium, the shape of the cranial vault can be used as an indicator of sex in the modern Greek population. Copyright © 2016. Published by Elsevier GmbH.

Etymology and Modern Linguistics

ERIC Educational Resources Information Center

Malkiel, Yakov

1975-01-01

Discusses the estrangement between etymology and modern linguistics, and concludes that a reconciliation between spatio-temporal linguistics and etymology must occur, because without it, both disciplines are doomed to inanition. (Author/AM)

The Challenge of Modern Church-Public Relations.

ERIC Educational Resources Information Center

Reagen, Michael V., Ed.; Chertow, Doris S., Ed.

Papers presented at the Institute on Modern Religious Communication Dilemmas, held at Syracuse University's Continuing Education Center for the Public Service in November 1971, are provided. The focus of the institute was the dilemmas facing modern church-public relations practitioners. The papers reproduced in this book provide a descriptive…

Modern Analytical Chemistry in the Contemporary World

ERIC Educational Resources Information Center

Šíma, Jan

2016-01-01

Students not familiar with chemistry tend to misinterpret analytical chemistry as some kind of the sorcery where analytical chemists working as modern wizards handle magical black boxes able to provide fascinating results. However, this approach is evidently improper and misleading. Therefore, the position of modern analytical chemistry among…

Code Modernization of VPIC

NASA Astrophysics Data System (ADS)

Bird, Robert; Nystrom, David; Albright, Brian

2017-10-01

The ability of scientific simulations to effectively deliver performant computation is increasingly being challenged by successive generations of high-performance computing architectures. Code development to support efficient computation on these modern architectures is both expensive, and highly complex; if it is approached without due care, it may also not be directly transferable between subsequent hardware generations. Previous works have discussed techniques to support the process of adapting a legacy code for modern hardware generations, but despite the breakthroughs in the areas of mini-app development, portable-performance, and cache oblivious algorithms the problem still remains largely unsolved. In this work we demonstrate how a focus on platform agnostic modern code-development can be applied to Particle-in-Cell (PIC) simulations to facilitate effective scientific delivery. This work builds directly on our previous work optimizing VPIC, in which we replaced intrinsic based vectorisation with compile generated auto-vectorization to improve the performance and portability of VPIC. In this work we present the use of a specialized SIMD queue for processing some particle operations, and also preview a GPU capable OpenMP variant of VPIC. Finally we include a lessons learnt. Work performed under the auspices of the U.S. Dept. of Energy by the Los Alamos National Security, LLC Los Alamos National Laboratory under contract DE-AC52-06NA25396 and supported by the LANL LDRD program.

Oceanic dispersal, vicariance and human introduction shaped the modern distribution of the termites Reticulitermes, Heterotermes and Coptotermes.

PubMed

Bourguignon, Thomas; Lo, Nathan; Šobotník, Jan; Sillam-Dussès, David; Roisin, Yves; Evans, Theodore A

2016-03-30

Reticulitermes, Heterotermes and Coptotermes form a small termite clade with partly overlapping distributions. Although native species occur across all continents, the factors influencing their distribution are poorly known. Here, we reconstructed the historical biogeography of these termites using mitochondrial genomes of species collected on six continents. Our analyses showed that Reticulitermes split from Heterotermes + Coptotermesat 59.5 Ma (49.9-69.5 Ma 95% CI), yet the oldest split within Reticulitermes(Eurasia and North America) is 16.1 Ma (13.4-19.5 Ma) and the oldest split within Heterotermes + Coptotermesis 36.0 Ma (33.9-40.5 Ma). We detected 14 disjunctions between biogeographical realms, all of which occurred within the last 34 Ma, not only after the break-up of Pangaea, but also with the continents in similar to current positions. Land dispersal over land bridges explained four disjunctions, oceanic dispersal by wood rafting explained eight disjunctions, and human introduction was the source of two recent disjunctions. These wood-eating termites, therefore, appear to have acquired their modern worldwide distribution through multiple dispersal processes, with oceanic dispersal and human introduction favoured by the ecological traits of nesting in wood and producing replacement reproductives. © 2016 The Author(s).

Oceanic dispersal, vicariance and human introduction shaped the modern distribution of the termites Reticulitermes, Heterotermes and Coptotermes

PubMed Central

Bourguignon, Thomas; Lo, Nathan; Šobotník, Jan; Sillam-Dussès, David; Roisin, Yves; Evans, Theodore A.

2016-01-01

Reticulitermes, Heterotermes and Coptotermes form a small termite clade with partly overlapping distributions. Although native species occur across all continents, the factors influencing their distribution are poorly known. Here, we reconstructed the historical biogeography of these termites using mitochondrial genomes of species collected on six continents. Our analyses showed that Reticulitermes split from Heterotermes + Coptotermes at 59.5 Ma (49.9–69.5 Ma 95% CI), yet the oldest split within Reticulitermes (Eurasia and North America) is 16.1 Ma (13.4–19.5 Ma) and the oldest split within Heterotermes + Coptotermes is 36.0 Ma (33.9–40.5 Ma). We detected 14 disjunctions between biogeographical realms, all of which occurred within the last 34 Ma, not only after the break-up of Pangaea, but also with the continents in similar to current positions. Land dispersal over land bridges explained four disjunctions, oceanic dispersal by wood rafting explained eight disjunctions, and human introduction was the source of two recent disjunctions. These wood-eating termites, therefore, appear to have acquired their modern worldwide distribution through multiple dispersal processes, with oceanic dispersal and human introduction favoured by the ecological traits of nesting in wood and producing replacement reproductives. PMID:27030416

Modernization of US Nuclear Forces: Costs in Perspective

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

Tapia-Jimenez, D.

This short research paper addresses two topics that have emerged in the debate about whether, when, and how to modernize U.S. nuclear forces.1 The first topic relates to the size and scale of the planned nuclear force, with some critics of the modernization plan arguing that the United States is simply replicating the Cold War force for a very different era. The second topic relates to the cost of the modernization effort, with some critics arguing that the cost is unaffordable.2 This paper begins with a review of the changes in the size and scale of U.S. nuclear forces sincemore » the Cold War. It then examines the expected costs of modernization in a comparative perspective.« less

Shaping up synthetic cells

NASA Astrophysics Data System (ADS)

Mulla, Yuval; Aufderhorst-Roberts, Anders; Koenderink, Gijsje H.

2018-07-01

How do the cells in our body reconfigure their shape to achieve complex tasks like migration and mitosis, yet maintain their shape in response to forces exerted by, for instance, blood flow and muscle action? Cell shape control is defined by a delicate mechanical balance between active force generation and passive material properties of the plasma membrane and the cytoskeleton. The cytoskeleton forms a space-spanning fibrous network comprising three subsystems: actin, microtubules and intermediate filaments. Bottom-up reconstitution of minimal synthetic cells where these cytoskeletal subsystems are encapsulated inside a lipid vesicle provides a powerful avenue to dissect the force balance that governs cell shape control. Although encapsulation is technically demanding, a steady stream of advances in this technique has made the reconstitution of shape-changing minimal cells increasingly feasible. In this topical review we provide a route-map of the recent advances in cytoskeletal encapsulation techniques and outline recent reports that demonstrate shape change phenomena in simple biomimetic vesicle systems. We end with an outlook toward the next steps required to achieve more complex shape changes with the ultimate aim of building a fully functional synthetic cell with the capability to autonomously grow, divide and move.

PubChem3D: Shape compatibility filtering using molecular shape quadrupoles

PubMed Central

2011-01-01

Background PubChem provides a 3-D neighboring relationship, which involves finding the maximal shape overlap between two static compound 3-D conformations, a computationally intensive step. It is highly desirable to avoid this overlap computation, especially if it can be determined with certainty that a conformer pair cannot meet the criteria to be a 3-D neighbor. As such, PubChem employs a series of pre-filters, based on the concept of volume, to remove approximately 65% of all conformer neighbor pairs prior to shape overlap optimization. Given that molecular volume, a somewhat vague concept, is rather effective, it leads one to wonder: can the existing PubChem 3-D neighboring relationship, which consists of billions of shape similar conformer pairs from tens of millions of unique small molecules, be used to identify additional shape descriptor relationships? Or, put more specifically, can one place an upper bound on shape similarity using other "fuzzy" shape-like concepts like length, width, and height? Results Using a basis set of 4.18 billion 3-D neighbor pairs identified from single conformer per compound neighboring of 17.1 million molecules, shape descriptors were computed for all conformers. These steric shape descriptors included several forms of molecular volume and shape quadrupoles, which essentially embody the length, width, and height of a conformer. For a given 3-D neighbor conformer pair, the volume and each quadrupole component (Qx, Qy, and Qz) were binned and their frequency of occurrence was examined. Per molecular volume type, this effectively produced three different maps, one per quadrupole component (Qx, Qy, and Qz), of allowed values for the similarity metric, shape Tanimoto (ST) ≥ 0.8. The efficiency of these relationships (in terms of true positive, true negative, false positive and false negative) as a function of ST threshold was determined in a test run of 13.2 billion conformer pairs not previously considered by the 3-D neighbor set

SHAPEMOL: the companion to SHAPE in the molecular era of ALMA and HERSCHEL

NASA Astrophysics Data System (ADS)

Santander-García, M.; Bujarrabal, V.; Alcolea, J.

2013-05-01

Modern instrumentation in radioastronomy constitutes a valuable tool for studying the Universe: ALMA will reach unprecedented sensitivities and spatial resolution, while Herschel/HIFI has opened a new window (most of the sub-mm and far infrared ranges are only accessible from space) for probing molecular warm gas (˜50-1000 K), complementing ground-based telescopes, which are better suited to study molecular molecular gas with temperatures under ˜100 K. On the other hand, the SHAPE software has emerged in the last few years as the standard tool for determinging the morphology and velocity field of different kinds of gaseous nebulae (mainly planetary nebulae, protoplanetary nebulae and nebulae around massive stars, although it can also be applied to H II regions and molecular clouds) via spatio-kinematical modelling. Standard SHAPE implements radiative transfer solving, but it is only available for atomic species and not for molecules. Being aware of the growing importance of the development of tools for easying the analyses of molecular data from new era observatories, we introduce the computer code shapemol, a plug-in for SHAPE with which we intend to fill the so far empty molecular niche. shapemol enables spatio-kinematic modeling with accurate non-LTE calculations of line excitation and radiative transfer in molecular species. This code has been succesfully tested in the study of the excitation conditions of the molecular envelope of the planetary nebula NGC 7027 using data from Herschel/HIFI and IRAM 30m. Currently, it allows radiative transfer solving in the ^{12}CO and ^{13}CO J=1-0 to J=17-16 lines. shapemol, used along SHAPE, allows to easily generate synthetic maps to test against interferometric observations, as well as synthetic line profiles to match single-dish observations.

Long-Time Stability of Ni-Ti-Shape Memory Alloys for Automotive Safety Systems

NASA Astrophysics Data System (ADS)

Strittmatter, Joachim; Gümpel, Paul

2011-07-01

In automotive a lot of electromagnetically, pyrotechnically or mechanically driven actuators are integrated to run comfort systems and to control safety systems in modern passenger cars. Using shape memory alloys (SMA) the existing systems could be simplified, performing the same function through new mechanisms with reduced size, weight, and costs. A drawback for the use of SMA in safety systems is the lack of materials knowledge concerning the durability of the switching function (long-time stability of the shape memory effect). Pedestrian safety systems play a significant role to reduce injuries and fatal casualties caused by accidents. One automotive safety system for pedestrian protection is the bonnet lifting system. Based on such an application, this article gives an introduction to existing bonnet lifting systems for pedestrian protection, describes the use of quick changing shape memory actuators and the results of the study concerning the long-time stability of the tested NiTi-wires. These wires were trained, exposed up to 4 years at elevated temperatures (up to 140 °C) and tested regarding their phase change temperatures, times, and strokes. For example, it was found that A P-temperature is shifted toward higher temperatures with longer exposing periods and higher temperatures. However, in the functional testing plant a delay in the switching time could not be detected. This article gives some answers concerning the long-time stability of NiTi-wires that were missing till now. With this knowledge, the number of future automotive applications using SMA can be increased. It can be concluded, that the use of quick changing shape memory actuators in safety systems could simplify the mechanism, reduce maintenance and manufacturing costs and should be insertable also for other automotive applications.

Incorporate Technology into the Modern Language Classroom

ERIC Educational Resources Information Center

Castleberry, Gwen Troxell; Evers, Rebecca B.

2010-01-01

This column describes how technology can enrich the learning environment provided by the modern language classroom. Typically, modern languages taught in U.S. public schools are French, Spanish, and German. A general broadening of high school graduation and college and professional school admission requirements to include a certain level of modern…

Childhood and Citizenship: A Conversation across Modernity

ERIC Educational Resources Information Center

Dunne, Joseph

2006-01-01

This paper analyses the problematic nature of citizenship as a modern achievement faced with the challenge of vindicating ancient ideals in what is increasingly considered to be a "postmodern" world. It offers a parallel analysis of childhood as a characteristically modern construct whose reality in children's life-worlds is threatened…

[The thinking about modern biological technology].

PubMed

Zhu, Rui-Liang; Yang, Xiao-Ming; Cui, Zhi-Zhong

2002-01-01

The way of life and mode of thinking of mankind is being changed by modern biological technology. It may be come true again that coexist and evolution of man and nature because the development of modern biological technology, but it also cannot avoid produce some new problem which made people have a think deeply to biological warfare, ethics and morals, law, society, food safety, production of industry and agriculture, energy resources, environment.

Paleoclimate effects and geographic barriers shape regional population genetic structure of blackbrush (Coleogyne ramosissima: Rosaceae)

Treesearch

Bryce A. Richardson; Susan E. Meyer

2012-01-01

Coleogyne ramosissima Torr. (blackbrush) is a dominant xerophytic shrub species in the ecotone between the warm and cold deserts of interior western North America. Amplified fragment length polymorphisms (AFLPs) were used to survey genetic diversity and population genetic structure at 14 collection sites across the species range. Analysis revealed significant...

Reconstructing liver shape and position from MR image slices using an active shape model

NASA Astrophysics Data System (ADS)

Fenchel, Matthias; Thesen, Stefan; Schilling, Andreas

2008-03-01

We present an algorithm for fully automatic reconstruction of 3D position, orientation and shape of the human liver from a sparsely covering set of n 2D MR slice images. Reconstructing the shape of an organ from slice images can be used for scan planning, for surgical planning or other purposes where 3D anatomical knowledge has to be inferred from sparse slices. The algorithm is based on adapting an active shape model of the liver surface to a given set of slice images. The active shape model is created from a training set of liver segmentations from a group of volunteers. The training set is set up with semi-manual segmentations of T1-weighted volumetric MR images. Searching for the optimal shape model that best fits to the image data is done by maximizing a similarity measure based on local appearance at the surface. Two different algorithms for the active shape model search are proposed and compared: both algorithms seek to maximize the a-posteriori probability of the grey level appearance around the surface while constraining the surface to the space of valid shapes. The first algorithm works by using grey value profile statistics in normal direction. The second algorithm uses average and variance images to calculate the local surface appearance on the fly. Both algorithms are validated by fitting the active shape model to abdominal 2D slice images and comparing the shapes, which have been reconstructed, to the manual segmentations and to the results of active shape model searches from 3D image data. The results turn out to be promising and competitive to active shape model segmentations from 3D data.

On Distinctions between Classical and Modern Rhetoric.

ERIC Educational Resources Information Center

Ede, Lisa; Lunsford, Andrea

The emergence of a modern or "new" rhetoric has been characterized by its attempt both to recover and reexamine the concepts of classical rhetoric and to define itself against that classical tradition. The distinctions that are persistently drawn between classical and modern rhetoric fall under four related heads: images of man and…

Code-Switching Functions in Modern Hebrew Teaching and Learning

ERIC Educational Resources Information Center

Gilead, Yona

2016-01-01

The teaching and learning of Modern Hebrew outside of Israel is essential to Jewish education and identity. One of the most contested issues in Modern Hebrew pedagogy is the use of code-switching between Modern Hebrew and learners' first language. Moreover, this is one of the longest running disputes in the broader field of second language…

Modern roundabouts for Oregon

DOT National Transportation Integrated Search

1998-06-01

This report reviews current research and practice on modern roundabouts, both in the US and other countries. The report compares the advantages and disadvantages of roundabouts, summarizes safety implications, and discusses pedestrian and bicyclist c...

Robust, optimal subsonic airfoil shapes

NASA Technical Reports Server (NTRS)

Rai, Man Mohan (Inventor)

2008-01-01

Method system, and product from application of the method, for design of a subsonic airfoil shape, beginning with an arbitrary initial airfoil shape and incorporating one or more constraints on the airfoil geometric parameters and flow characteristics. The resulting design is robust against variations in airfoil dimensions and local airfoil shape introduced in the airfoil manufacturing process. A perturbation procedure provides a class of airfoil shapes, beginning with an initial airfoil shape.

Multifunctional shape-memory polymers.

PubMed

Behl, Marc; Razzaq, Muhammad Yasar; Lendlein, Andreas

2010-08-17

The thermally-induced shape-memory effect (SME) is the capability of a material to change its shape in a predefined way in response to heat. In shape-memory polymers (SMP) this shape change is the entropy-driven recovery of a mechanical deformation, which was obtained before by application of external stress and was temporarily fixed by formation of physical crosslinks. The high technological significance of SMP becomes apparent in many established products (e.g., packaging materials, assembling devices, textiles, and membranes) and the broad SMP development activities in the field of biomedical as well as aerospace applications (e.g., medical devices or morphing structures for aerospace vehicles). Inspired by the complex and diverse requirements of these applications fundamental research is aiming at multifunctional SMP, in which SME is combined with additional functions and is proceeding rapidly. In this review different concepts for the creation of multifunctionality are derived from the various polymer network architectures of thermally-induced SMP. Multimaterial systems, such as nanocomposites, are described as well as one-component polymer systems, in which independent functions are integrated. Future challenges will be to transfer the concept of multifunctionality to other emerging shape-memory technologies like light-sensitive SMP, reversible shape changing effects or triple-shape polymers.

Shaping Crystal-Crystal Phase Transitions

NASA Astrophysics Data System (ADS)

Du, Xiyu; van Anders, Greg; Dshemuchadse, Julia; Glotzer, Sharon

Previous computational and experimental studies have shown self-assembled structure depends strongly on building block shape. New synthesis techniques have led to building blocks with reconfigurable shape and it has been demonstrated that building block reconfiguration can induce bulk structural reconfiguration. However, we do not understand systematically how this transition happens as a function of building block shape. Using a recently developed ``digital alchemy'' framework, we study the thermodynamics of shape-driven crystal-crystal transitions. We find examples of shape-driven bulk reconfiguration that are accompanied by first-order phase transitions, and bulk reconfiguration that occurs without any thermodynamic phase transition. Our results suggest that for well-chosen shapes and structures, there exist facile means of bulk reconfiguration, and that shape-driven bulk reconfiguration provides a viable mechanism for developing functional materials.

Modern Cast Irons in Chemical Engineering

DTIC Science & Technology

1934-11-09

fl’ceew. T I SOCIETY OF CHEMICAL INDUSTRY CHEMICAL ENGINEERING GROUP MODERN CAST IRONS IN CHEMICAL ENGINEERING By J. G. PEARCE, M.Sc., F.Inst.P...CAST IRONS IN CHEMICAL ENGINEERING By J. G. PEARCE, M.Sc., F.Inst.P., M.I.E.E.* INTRODUCTION to chemical or thermal resistance. Small blow-holes Any...consideration of modern cast irons in chemical seldom appear to reduce the mechanical strength of engineering should strictly be prefaced by a definition

Knowledge in motion: The cultural politics of modern science translations in Arabic.

PubMed

Elshakry, Marwa S

2008-12-01

This essay looks at the problem of the global circulation of modem scientific knowledge by looking at science translations in modern Arabic. In the commercial centers of the late Ottoman Empire, emerging transnational networks lay behind the development of new communities of knowledge, many of which sought to break with old linguistic and literary norms to redefine the basis of their authority. Far from acting as neutral purveyors of "universal truths," scientific translations thus served as key instruments in this ongoing process of sociopolitical and epistemological transformation and mediation. Fierce debates over translators' linguistic strategies and choices involved deliberations over the character of language and the nature of "science" itself. They were also crucially shaped by such geopolitical factors as the rise of European imperialism and anticolonial nationalism in the region. The essay concludes by arguing for the need for greater attention to the local factors involved in the translation of scientific concepts across borders.

The Hue of Shapes

ERIC Educational Resources Information Center

Albertazzi, Liliana; Da Pos, Osvaldo; Canal, Luisa; Micciolo, Rocco; Malfatti, Michela; Vescovi, Massimo

2013-01-01

This article presents an experimental study on the naturally biased association between shape and color. For each basic geometric shape studied, participants were asked to indicate the color perceived as most closely related to it, choosing from the Natural Color System Hue Circle. Results show that the choices of color for each shape were not…

Modernizing Mechanical Services.

ERIC Educational Resources Information Center

Rutgers, Norman L.

Some of the problems of renovating school buildings and in particular the modernization of mechanical services in existing facilities are discussed. According to school management publications, approximately 42 per cent of our elementary and 59 per cent of our secondary schools are 15 years old or older. School plants, which were built 12 to 15…

3D shape representation with spatial probabilistic distribution of intrinsic shape keypoints

NASA Astrophysics Data System (ADS)

Ghorpade, Vijaya K.; Checchin, Paul; Malaterre, Laurent; Trassoudaine, Laurent

2017-12-01

The accelerated advancement in modeling, digitizing, and visualizing techniques for 3D shapes has led to an increasing amount of 3D models creation and usage, thanks to the 3D sensors which are readily available and easy to utilize. As a result, determining the similarity between 3D shapes has become consequential and is a fundamental task in shape-based recognition, retrieval, clustering, and classification. Several decades of research in Content-Based Information Retrieval (CBIR) has resulted in diverse techniques for 2D and 3D shape or object classification/retrieval and many benchmark data sets. In this article, a novel technique for 3D shape representation and object classification has been proposed based on analyses of spatial, geometric distributions of 3D keypoints. These distributions capture the intrinsic geometric structure of 3D objects. The result of the approach is a probability distribution function (PDF) produced from spatial disposition of 3D keypoints, keypoints which are stable on object surface and invariant to pose changes. Each class/instance of an object can be uniquely represented by a PDF. This shape representation is robust yet with a simple idea, easy to implement but fast enough to compute. Both Euclidean and topological space on object's surface are considered to build the PDFs. Topology-based geodesic distances between keypoints exploit the non-planar surface properties of the object. The performance of the novel shape signature is tested with object classification accuracy. The classification efficacy of the new shape analysis method is evaluated on a new dataset acquired with a Time-of-Flight camera, and also, a comparative evaluation on a standard benchmark dataset with state-of-the-art methods is performed. Experimental results demonstrate superior classification performance of the new approach on RGB-D dataset and depth data.

Abstract shapes of RNA.

PubMed

Giegerich, Robert; Voss, Björn; Rehmsmeier, Marc

2004-01-01

The function of a non-protein-coding RNA is often determined by its structure. Since experimental determination of RNA structure is time-consuming and expensive, its computational prediction is of great interest, and efficient solutions based on thermodynamic parameters are known. Frequently, however, the predicted minimum free energy structures are not the native ones, leading to the necessity of generating suboptimal solutions. While this can be accomplished by a number of programs, the user is often confronted with large outputs of similar structures, although he or she is interested in structures with more fundamental differences, or, in other words, with different abstract shapes. Here, we formalize the concept of abstract shapes and introduce their efficient computation. Each shape of an RNA molecule comprises a class of similar structures and has a representative structure of minimal free energy within the class. Shape analysis is implemented in the program RNAshapes. We applied RNAshapes to the prediction of optimal and suboptimal abstract shapes of several RNAs. For a given energy range, the number of shapes is considerably smaller than the number of structures, and in all cases, the native structures were among the top shape representatives. This demonstrates that the researcher can quickly focus on the structures of interest, without processing up to thousands of near-optimal solutions. We complement this study with a large-scale analysis of the growth behaviour of structure and shape spaces. RNAshapes is available for download and as an online version on the Bielefeld Bioinformatics Server.

Shape Control of Solar Collectors Using Shape Memory Alloy Actuators

NASA Technical Reports Server (NTRS)

Lobitz, D. W.; Grossman, J. W.; Allen, J. J.; Rice, T. M.; Liang, C.; Davidson, F. M.

1996-01-01

Solar collectors that are focused on a central receiver are designed with a mechanism for defocusing the collector or disabling it by turning it out of the path of the sun's rays. This is required to avoid damaging the receiver during periods of inoperability. In either of these two cases a fail-safe operation is very desirable where during power outages the collector passively goes to its defocused or deactivated state. This paper is principally concerned with focusing and defocusing the collector in a fail-safe manner using shape memory alloy actuators. Shape memory alloys are well suited to this application in that once calibrated the actuators can be operated in an on/off mode using a minimal amount of electric power. Also, in contrast to other smart materials that were investigated for this application, shape memory alloys are capable of providing enough stroke at the appropriate force levels to focus the collector. Design and analysis details presented, along with comparisons to test data taken from an actual prototype, demonstrate that the collector can be repeatedly focused and defocused within accuracies required by typical solar energy systems. In this paper the design, analysis and testing of a solar collector which is deformed into its desired shape by shape memory alloy actuators is presented. Computations indicate collector shapes much closer to spherical and with smaller focal lengths can be achieved by moving the actuators inward to a radius of approximately 6 inches. This would require actuators with considerably more stroke and some alternate SMA actuators are currently under consideration. Whatever SMA actuator is finally chosen for this application, repeatability and fatigue tests will be required to investigate the long term performance of the actuator.

Probing Sizes and Shapes of Nobelium Isotopes by Laser Spectroscopy

NASA Astrophysics Data System (ADS)

Raeder, S.; Ackermann, D.; Backe, H.; Beerwerth, R.; Berengut, J. C.; Block, M.; Borschevsky, A.; Cheal, B.; Chhetri, P.; Düllmann, Ch. E.; Dzuba, V. A.; Eliav, E.; Even, J.; Ferrer, R.; Flambaum, V. V.; Fritzsche, S.; Giacoppo, F.; Götz, S.; Heßberger, F. P.; Huyse, M.; Kaldor, U.; Kaleja, O.; Khuyagbaatar, J.; Kunz, P.; Laatiaoui, M.; Lautenschläger, F.; Lauth, W.; Mistry, A. K.; Minaya Ramirez, E.; Nazarewicz, W.; Porsev, S. G.; Safronova, M. S.; Safronova, U. I.; Schuetrumpf, B.; Van Duppen, P.; Walther, T.; Wraith, C.; Yakushev, A.

2018-06-01

Until recently, ground-state nuclear moments of the heaviest nuclei could only be inferred from nuclear spectroscopy, where model assumptions are required. Laser spectroscopy in combination with modern atomic structure calculations is now able to probe these moments directly, in a comprehensive and nuclear-model-independent way. Here we report on unique access to the differential mean-square charge radii of No 252 ,253 ,254 , and therefore to changes in nuclear size and shape. State-of-the-art nuclear density functional calculations describe well the changes in nuclear charge radii in the region of the heavy actinides, indicating an appreciable central depression in the deformed proton density distribution in No,254252 isotopes. Finally, the hyperfine splitting of No 253 was evaluated, enabling a complementary measure of its (quadrupole) deformation, as well as an insight into the neutron single-particle wave function via the nuclear spin and magnetic moment.

[The contribution of L.G. Ramensky theoretical legacy to modern vegetation science (to the 130 anniversary of the scientist's birth)].

PubMed

Mirkin, B M; Naumova, L G

2015-01-01

L.G. Ramensky (1884-1953) was an outstanding Soviet geobotanist of the first part of XX century. Considered is his theoretical legacy and its contribution to modern vegetation science. L.G. Ramensky formulated the principle of vegetation continuum based on which the modern paradigm of vegetation science has been put into shape. The scientist made a contribution to the development of such important theoretical conceptions as types of plant strategy, coenosis and coenobiosis (coexistence of species), patterns of interannual variability in plant communities, ecological successions. The unique ecological scales were established by L.G. Ramensky that characterize the distribution of 1400 species over the gradients of soil moistening, richness, and salinization as well as moistening variability, pastoral digression, and alluvial intensity. He came out against mechanistic notions by V.N. Sukachev on a biogeocoenosis structure. The scientist did not offer his own method of plant communities classification but his well-reasoned criticism of dominant classification played a great role in adoption of floristical classification principles (Braun-Blanquet approach) by phytocenology in our country.

Mapping RNA Structure In Vitro with SHAPE Chemistry and Next-Generation Sequencing (SHAPE-Seq).

PubMed

Watters, Kyle E; Lucks, Julius B

2016-01-01

Mapping RNA structure with selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) chemistry has proven to be a versatile method for characterizing RNA structure in a variety of contexts. SHAPE reagents covalently modify RNAs in a structure-dependent manner to create adducts at the 2'-OH group of the ribose backbone at nucleotides that are structurally flexible. The positions of these adducts are detected using reverse transcriptase (RT) primer extension, which stops one nucleotide before the modification, to create a pool of cDNAs whose lengths reflect the location of SHAPE modification. Quantification of the cDNA pools is used to estimate the "reactivity" of each nucleotide in an RNA molecule to the SHAPE reagent. High reactivities indicate nucleotides that are structurally flexible, while low reactivities indicate nucleotides that are inflexible. These SHAPE reactivities can then be used to infer RNA structures by restraining RNA structure prediction algorithms. Here, we provide a state-of-the-art protocol describing how to perform in vitro RNA structure probing with SHAPE chemistry using next-generation sequencing to quantify cDNA pools and estimate reactivities (SHAPE-Seq). The use of next-generation sequencing allows for higher throughput, more consistent data analysis, and multiplexing capabilities. The technique described herein, SHAPE-Seq v2.0, uses a universal reverse transcription priming site that is ligated to the RNA after SHAPE modification. The introduced priming site allows for the structural analysis of an RNA independent of its sequence.

[Shaping ability of two nickel-titanium rotary systems in simulated S-shaped canals].

PubMed

Luo, Hong-xia; Huang, Ding-ming; Zhang, Fu-hua; Tan, Hong; Zhou, Xue-dong

2008-01-01

To evaluate the shaping ability of two nickel-titanium rotary systems (ProTaper and Hero642) in simulated S-shaped canals. Thirty simulated S-shaped canals were randomly divided into three groups and prepared by ProTaper, Hero642, ProTaper combined with Hero642 respectively. All the canals were scanned before and after instrumentation, and the amount of material removed in the inner and outer wall and the canal width after instrumentation were measured with a computer image analysis program. There was significant difference in the amount of material removed at the inner side of apical curvature and outer side of apex between ProTaper combined with Hero642 and ProTaper files (P < 0.05) at the same tip size. The inner and outer wall of the canals were evenly prepared by ProTaper combined with Hero642, and the taper of canals were better than those prepared by Hero642. ProTaper combined with Hero 642 had better shaping ability to maintain the original shape and could create good taper canals in the simulated S-shaped canal model.

Groundwater shapes sediment biogeochemistry and microbial diversity in a submerged Great Lake sinkhole.

PubMed

Kinsman-Costello, L E; Sheik, C S; Sheldon, N D; Allen Burton, G; Costello, D M; Marcus, D; Uyl, P A Den; Dick, G J

2017-03-01

For a large part of earth's history, cyanobacterial mats thrived in low-oxygen conditions, yet our understanding of their ecological functioning is limited. Extant cyanobacterial mats provide windows into the putative functioning of ancient ecosystems, and they continue to mediate biogeochemical transformations and nutrient transport across the sediment-water interface in modern ecosystems. The structure and function of benthic mats are shaped by biogeochemical processes in underlying sediments. A modern cyanobacterial mat system in a submerged sinkhole of Lake Huron (LH) provides a unique opportunity to explore such sediment-mat interactions. In the Middle Island Sinkhole (MIS), seeping groundwater establishes a low-oxygen, sulfidic environment in which a microbial mat dominated by Phormidium and Planktothrix that is capable of both anoxygenic and oxygenic photosynthesis, as well as chemosynthesis, thrives. We explored the coupled microbial community composition and biogeochemical functioning of organic-rich, sulfidic sediments underlying the surface mat. Microbial communities were diverse and vertically stratified to 12 cm sediment depth. In contrast to previous studies, which used low-throughput or shotgun metagenomic approaches, our high-throughput 16S rRNA gene sequencing approach revealed extensive diversity. This diversity was present within microbial groups, including putative sulfate-reducing taxa of Deltaproteobacteria, some of which exhibited differential abundance patterns in the mats and with depth in the underlying sediments. The biological and geochemical conditions in the MIS were distinctly different from those in typical LH sediments of comparable depth. We found evidence for active cycling of sulfur, methane, and nutrients leading to high concentrations of sulfide, ammonium, and phosphorus in sediments underlying cyanobacterial mats. Indicators of nutrient availability were significantly related to MIS microbial community composition, while LH

Assessing Portuguese Guadiana Basin water management impacts under climate change and paleoclimate variability

NASA Astrophysics Data System (ADS)

Maia, Rodrigo; Oliveira, Bruno; Ramos, Vanessa; Brekke, Levi

2014-05-01

indicates an increase in temperatures and a reduction of the precipitation values which go well beyond the observed values and, therefore, must be forcefully included in any realistic proactive water resource management decision. Using the results of this study it is possible to estimate future water availability and consumption satisfaction allowing for the elaboration of informed management decisions. In this study, the CMIP 3 Global Climate Models were considered for the definition of the effects of climate change, using the median and extreme tendencies based on the range of variation of the multiple climate projection scenarios. The observed climate variability, along with these model-derived tendencies, were used to inform the hydrology and water management models for the historical and future periods, respectively. Additionally, for a more comprehensive analysis on climate variability, a stochastic model was implemented based on the paleoclimate variability obtained from tree-ring records.

Adapting construction staking to modern technology : final report.

DOT National Transportation Integrated Search

2017-08-01

This report summarizes the tasks and findings of the ICT Project R27-163, Adapting Construction Staking to Modern Technology, which aims to develop written procedures for the use of modern technologies (such as GPS and civil information modeling) in ...

Application of Modern Fortran to Spacecraft Trajectory Design and Optimization

NASA Technical Reports Server (NTRS)

Williams, Jacob; Falck, Robert D.; Beekman, Izaak B.

2018-01-01

In this paper, applications of the modern Fortran programming language to the field of spacecraft trajectory optimization and design are examined. Modern object-oriented Fortran has many advantages for scientific programming, although many legacy Fortran aerospace codes have not been upgraded to use the newer standards (or have been rewritten in other languages perceived to be more modern). NASA's Copernicus spacecraft trajectory optimization program, originally a combination of Fortran 77 and Fortran 95, has attempted to keep up with modern standards and makes significant use of the new language features. Various algorithms and methods are presented from trajectory tools such as Copernicus, as well as modern Fortran open source libraries and other projects.

Modern Languages and Antiracism.

ERIC Educational Resources Information Center

O'Shaughnessy, Martin

1988-01-01

Discusses a school language department's antiracist/multicultural policy for modern languages. The policy stresses the need for a multicultural curriculum, exploration of racism, acceptance of all languages, recognition of specialized knowledge, and positive images of people from ethnic minority groups. (CB)

Sources and Impacts of Modeled and Observed Low-Frequency Climate Variability

NASA Astrophysics Data System (ADS)

Parsons, Luke Alexander

structure of the variance spectrum has important consequences for the probability of multi-year drought. Our lake record suggests there is a significant background threat of multi-year, and even decade-length, drought in western Amazonia, whereas climate model simulations indicate most droughts likely last no longer than one to three years. These findings suggest climate models may underestimate the future risk of extended drought in this important region. In Appendix C, we expand our analysis of climate variability beyond South America. We use observations, well-constrained tropical paleoclimate, and Earth system model data to examine the overall shape of the climate spectrum across interannual to century frequencies. We find a general agreement among observations and models that temperature variability increases with timescale across most of the globe outside the tropics. However, as compared to paleoclimate records, climate models generate too little low-frequency variability in the tropics (e.g., Laepple and Huybers, 2014). When we compare the shape of the simulated climate spectrum to the spectrum of a simple autoregressive process, we find much of the modeled surface temperature variability in the tropics could be explained by ocean smoothing of weather noise. Importantly, modeled precipitation tends to be similar to white noise across much of the globe. By contrast, paleoclimate records of various types from around the globe indicate that both temperature and precipitation variability should experience much more low-frequency variability than a simple autoregressive or white-noise process. In summary, state-of-the-art climate models generate some degree of dynamically driven low-frequency climate variability, especially at high latitudes. However, the latest climate models, observations, and paleoclimate data provide us with drastically different pictures of the background climate system and its associated risks. This research has important consequences for improving

Thermal surface analysis on high-rise building façades with neo-minimalist and modern style in Penang, Malaysia

NASA Astrophysics Data System (ADS)

Arab, Yasser; Hassan, Ahmad Sanusi; Qanaa, Bushra

2017-10-01

This research analyzed the façade thermal performance of high-rise buildings with modern and neo-minimalist architectural style. Four high-rise apartment buildings in Penang Island are selected as case studies for this research. The modern architectural style, which was popular during the 1970s to 1990s, nearly disregarded the cultural identity of the country and used the basic geometric shapes in the design. Conversely, the neo-minimalist style is the popular style from the 2010s up to the present. This style is a result of the "less is more" concept, which means using minimal applications to obtain an efficient design. The four selected case studies are as follows: Halaman Kristal 2 and Mutiara Idaman 1 with modern architectural style and Light Linear and Baystar apartments with neo-minimalist style. The research uses Fluke Ti20 thermal imager to capture thermal images of the west façade of the selected case studies on an hourly basis from 12:00 to 6:00 P.M. on March 15, 2017. Results confirm that the neo-minimalist façade elements, such as balconies and recessed walls, as well as other shading elements, are effective in improving the performance of façade shading. Notably, façade shading causes low surface temperature and provides cool indoor atmosphere during the day when the temperature is extremely high outside. Accordingly, this distinct feature partly explains the current popularity of the neo-minimalist architectural style.

Interspecific variation in the tetradactyl manus of modern tapirs (Perissodactyla: Tapirus) exposed using geometric morphometrics.

PubMed

MacLaren, Jamie A; Nauwelaerts, Sandra

2017-11-01

The distal forelimb (autopodium) of quadrupedal mammals is a key morphological unit involved in locomotion, body support, and interaction with the substrate. The manus of the tapir (Perissodactyla: Tapirus) is unique within modern perissodactyls, as it retains the plesiomorphic tetradactyl (four-toed) condition also exhibited by basal equids and rhinoceroses. Tapirs are known to exhibit anatomical mesaxonic symmetry in the manus, although interspecific differences and biomechanical mesaxony have yet to be rigorously tested. Here, we investigate variation in the manus morphology of four modern tapir species (Tapirus indicus, Tapirus bairdii, Tapirus pinchaque, and Tapirus terrestris) using a geometric morphometric approach. Autopodial bones were laser scanned to capture surface shape and morphology was quantified using 3D-landmark analysis. Landmarks were aligned using Generalised Procrustes Analysis, with discriminant function and partial least square analyses performed on aligned coordinate data to identify features that significantly separate tapir species. Overall, our results support the previously held hypothesis that T. indicus is morphologically separate from neotropical tapirs; however, previous conclusions regarding function from morphological differences are shown to require reassessment. We find evidence indicating that T. bairdii exhibits reduced reliance on the lateral fifth digit compared to other tapirs. Morphometric assessment of the metacarpophalangeal joint and the morphology of the distal facets of the lunate lend evidence toward high loading on the lateral digits of both the large T. indicus (large body mass) and the small, long limbed T. pinchaque (ground impact). Our results support other recent studies on T. pinchaque, suggesting subtle but important adaptations to a compliant but inclined habitat. In conclusion, we demonstrate further evidence that the modern tapir forelimb is a variable locomotor unit with a range of interspecific features

Modern turtle origins: the oldest known cryptodire.

PubMed

Gaffney, E S; Hutchison, J H; Jenkins, F A; Meeker, L J

1987-07-17

The discovery of a turtle in the Early Jurassic(185 million years before present) Kayenta Formation of northeastern Arizona provides significant evidence about the origin of modern turtles. This new taxon possesses many of the primitive features expected in the hypothetical common ancestor of pleurodires and cryptodires, the two groups of modern turtles. It is identified as the oldest known cryptodire because of the presence of a distinctive cryptodiran jaw mechanism consisting of a trochlea over the otic chamber that redirects the line of action of the adductor muscle. Aquatic habits appear to have developed very early in turtle evolution. Kayentachelys extends the known record of cryptodires back at least 45 million years and documents a very early stage in the evolution of modern turtles.

Universality of fragment shapes.

PubMed

Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

2015-03-16

The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism.

Nuclear weapons modernization: Plans, programs, and issues for Congress

NASA Astrophysics Data System (ADS)

Woolf, Amy F.

2017-11-01

The United States is currently recapitalizing each delivery system in its "nuclear triad" and refurbishing many of the warheads carried by those systems. The plans for these modernization programs have raised a number of questions, both within Congress and among analysts in the nuclear weapons and arms control communities, about the costs associated with the programs and the need to recapitalize each leg of the triad at the same time. This paper covers four distinct issues. It begins with a brief review of the planned modernization programs, then addresses questions about why the United States is pursuing all of these modernization programs at this time. It then reviews the debate about how much these modernization programs are likely to cost in the next decade and considers possible changes that might reduce the cost. It concludes with some comments about congressional views on the modernization programs and prospects for continuing congressional support in the coming years.

The Divergence of Neandertal and Modern Human Y Chromosomes

PubMed Central

Mendez, Fernando L.; Poznik, G. David; Castellano, Sergi; Bustamante, Carlos D.

2016-01-01

Sequencing the genomes of extinct hominids has reshaped our understanding of modern human origins. Here, we analyze ∼120 kb of exome-captured Y-chromosome DNA from a Neandertal individual from El Sidrón, Spain. We investigate its divergence from orthologous chimpanzee and modern human sequences and find strong support for a model that places the Neandertal lineage as an outgroup to modern human Y chromosomes—including A00, the highly divergent basal haplogroup. We estimate that the time to the most recent common ancestor (TMRCA) of Neandertal and modern human Y chromosomes is ∼588 thousand years ago (kya) (95% confidence interval [CI]: 447–806 kya). This is ∼2.1 (95% CI: 1.7–2.9) times longer than the TMRCA of A00 and other extant modern human Y-chromosome lineages. This estimate suggests that the Y-chromosome divergence mirrors the population divergence of Neandertals and modern human ancestors, and it refutes alternative scenarios of a relatively recent or super-archaic origin of Neandertal Y chromosomes. The fact that the Neandertal Y we describe has never been observed in modern humans suggests that the lineage is most likely extinct. We identify protein-coding differences between Neandertal and modern human Y chromosomes, including potentially damaging changes to PCDH11Y, TMSB4Y, USP9Y, and KDM5D. Three of these changes are missense mutations in genes that produce male-specific minor histocompatibility (H-Y) antigens. Antigens derived from KDM5D, for example, are thought to elicit a maternal immune response during gestation. It is possible that incompatibilities at one or more of these genes played a role in the reproductive isolation of the two groups. PMID:27058445

The Divergence of Neandertal and Modern Human Y Chromosomes.

PubMed

Mendez, Fernando L; Poznik, G David; Castellano, Sergi; Bustamante, Carlos D

2016-04-07

Sequencing the genomes of extinct hominids has reshaped our understanding of modern human origins. Here, we analyze ∼120 kb of exome-captured Y-chromosome DNA from a Neandertal individual from El Sidrón, Spain. We investigate its divergence from orthologous chimpanzee and modern human sequences and find strong support for a model that places the Neandertal lineage as an outgroup to modern human Y chromosomes-including A00, the highly divergent basal haplogroup. We estimate that the time to the most recent common ancestor (TMRCA) of Neandertal and modern human Y chromosomes is ∼588 thousand years ago (kya) (95% confidence interval [CI]: 447-806 kya). This is ∼2.1 (95% CI: 1.7-2.9) times longer than the TMRCA of A00 and other extant modern human Y-chromosome lineages. This estimate suggests that the Y-chromosome divergence mirrors the population divergence of Neandertals and modern human ancestors, and it refutes alternative scenarios of a relatively recent or super-archaic origin of Neandertal Y chromosomes. The fact that the Neandertal Y we describe has never been observed in modern humans suggests that the lineage is most likely extinct. We identify protein-coding differences between Neandertal and modern human Y chromosomes, including potentially damaging changes to PCDH11Y, TMSB4Y, USP9Y, and KDM5D. Three of these changes are missense mutations in genes that produce male-specific minor histocompatibility (H-Y) antigens. Antigens derived from KDM5D, for example, are thought to elicit a maternal immune response during gestation. It is possible that incompatibilities at one or more of these genes played a role in the reproductive isolation of the two groups. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Problems of modern urban drainage in developing countries.

PubMed

Silveira, A L L

2002-01-01

Socio-economic factors in developing countries make it more difficult to solve problems of urban drainage than in countries that are more advanced. Factors inhibiting the adoption of modern solutions include: (1) in matters of urban drainage, 19th-century sanitary philosophy still dominates; (2) both legal and clandestine land settlement limits the space that modern solutions require; (3) contamination of storm runoff by foul sewage, sediment and garbage prevents adoption of developed-country practices; (4) climatic and socio-economic factors favour the growth of epidemics where runoff is retained for flood-avoidance and to increase infiltration; (5) lack of a technological basis for adequate drainage management and design; (6) lack of the interaction between community and city administration that is needed to obtain modern solutions to urban drainage problems. Awareness of these difficulties is fundamental to the search for modern and viable solutions appropriate for developing countries.

White House Forum on Modernizing Government

NASA Image and Video Library

2010-01-14

NASA Deputy Administrator Lori Garver, left, talks with Deputy Secretary of Education Tony Miller prior to the start of the White House Forum on Modernizing Government held Thursday, Jan. 14, 2010 at the Old Executive Office Building in Washington. As part of his commitment to change how business is done in Washington and instill a new sense of responsibility for taxpayer dollars, the President welcomed more than 50 of the country’s top CEOs to the White House Forum on Modernizing Government. Photo Credit: (NASA/Bill Ingalls)

78 FR 68097 - Meeting of the Military Compensation and Retirement Modernization Commission

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-13

... MILITARY COMPENSATION AND RETIREMENT MODERNIZATION COMMISSION Meeting of the Military Compensation and Retirement Modernization Commission AGENCY: Military Compensation and Retirement Modernization Commission. ACTION: Notice of public meeting. SUMMARY: The Military Compensation and Retirement Modernization...

[Discussion on knowledge structural system of modern acupuncture professionals].

PubMed

Wang, Qin-Yu; Li, Su-He

2012-02-01

To explore the knowledge structural system that the modern acupuncture professionals should have. The current situation of personnel training for modern acupuncture professionals was multi-dimensionally and comprehensively analyzed from course offering of higher education, laws of famous physicians growth, and discipline development features of the acupuncture and moxibustion subject, and suggestions were made to the shortages. The reasonable knowledge structural system that the modern acupuncture professionals should have included establishment of good Chinese medicine thoughts, mastery of complete Chinese medicine therapy, and ability of followup of dynamic development of subject. The reformation of course design is imperative in order to promote the reasonable knowledge structural system formation of modern acupuncture professionals.

Influence of shovel-shaped incisors on the dental arch crowding in Mongolian females.

PubMed

Hasegawa, Yuh; Terada, Kazuto; Kageyama, Ikuo; Tsukada, Shin-ichi; Uzuka, Satoshi; Nakahara, Rizako; Nakahara, Sen

2009-08-01

The aim of this study was to investigate the influences of shovel-shaped incisors on the dental arch crowding in the samples of modern young female adult Mongolians (belonging to the Khalkha-Mogol grouping) ranged between 18.5 and 25.0 years, with a mean age of 20.7 years. Materials in this study comprised of 33 dental casts. Plaster replicas of the A.S.U. system plaques were used to facilitate standardization in scoring and classify shoveling regarding both upper central and lateral incisors. Dimensions of the dental arch namely, overjet, overbite, arch depth, arch width and irregularity index were measured. The correlation between the shovel shape of the central incisor and the lateral incisor was highly significant. Significantly relations were found between the grades of shoveling and the mesiodistal diameters of upper first molars and lower incisors. Positive correlation was admitted between the shoveling and upper arch depth anterior, and upper arch depth. It may be considered that the grades of shoveling are indirectly related with upper and/or lower anterior crowding. Although crowding is looks like an expression of disharmony between teeth and alveolar arch, it may be caused by multiple etiologic factors interacted directly and/or indirectly.

Evaluation of organic geochemical and micropaleontological proxies for Holocene paleoclimate reconstructions in Tampa Bay, Florida

NASA Astrophysics Data System (ADS)

van Soelen, E. E.; Brooks, G.; Lammertsma, E.; Donders, T.; Wagner-Cremer, F.; Sangiorgi, F.; Cremer, H.; Sinninghe Damsté, J. S.; Reichart, G. J.

2009-04-01

The exact consequences of human induced climate change are as yet not known. One of the current debates concerns the relation between rising sea surface temperatures (SST) and enhanced hurricane activity. It has also been suggested that the El Niño Southern Oscillation (ENSO) variability plays a major role in providing favorable circumstances for hurricane development. Paleo-climate reconstructions can help understanding long-term trends in hurricane activity. However, reliable climate reconstructions first require that suitable proxies are developed and tested. For this purpose, a pilot-study was performed using biomarkers, pollen, dinoflagellates and diatoms in a core from Tampa-Bay, Florida, covering the Holocene. The hydrological cycle in this part of Florida is strongly affected by both ENSO [1] and hurricanes. Biomarkers of both terrestrial and marine origin were abundant in the core sediments. High taraxerol concentrations were found which are characteristic for the close proximity of mangrove forests on the bays fringes. Other vascular plant derived biomarkers include friedelanone and β-sitosterol. Marine biomarkers include amongst others dinosterol and long-chain C37 and C38 alkenones, indicative for dinoflagellates and haptophyte algae respectively. These biomarkers are absent in sediments older than 7 kyr BP, indicating a non-marine depositional environment. In sediments younger than 7 kyr BP, increasing amounts of marine biomarkers indicate a transition towards estuarine conditions. SST was reconstructed on the alkenones-based paleothermometer Uk'37 and indicates temperatures of ~ 26°C for the past ~4 kyr. Between 7 and 4 kyr BP, concentrations of alkenones in the sediments are too low for reliable SST reconstructions. The shift towards estuarine conditions is a consequence of rising sea-levels following the last deglaciation and is in agreement with earlier findings by Cronin et al. [2], who recognized a change from lacustrine to marine sediments

Active shape models unleashed

NASA Astrophysics Data System (ADS)

Kirschner, Matthias; Wesarg, Stefan

2011-03-01

Active Shape Models (ASMs) are a popular family of segmentation algorithms which combine local appearance models for boundary detection with a statistical shape model (SSM). They are especially popular in medical imaging due to their ability for fast and accurate segmentation of anatomical structures even in large and noisy 3D images. A well-known limitation of ASMs is that the shape constraints are over-restrictive, because the segmentations are bounded by the Principal Component Analysis (PCA) subspace learned from the training data. To overcome this limitation, we propose a new energy minimization approach which combines an external image energy with an internal shape model energy. Our shape energy uses the Distance From Feature Space (DFFS) concept to allow deviations from the PCA subspace in a theoretically sound and computationally fast way. In contrast to previous approaches, our model does not rely on post-processing with constrained free-form deformation or additional complex local energy models. In addition to the energy minimization approach, we propose a new method for liver detection, a new method for initializing an SSM and an improved k-Nearest Neighbour (kNN)-classifier for boundary detection. Our ASM is evaluated with leave-one-out tests on a data set with 34 tomographic CT scans of the liver and is compared to an ASM with standard shape constraints. The quantitative results of our experiments show that we achieve higher segmentation accuracy with our energy minimization approach than with standard shape constraints.nym

Constraining Modern and Historic Mercury Emissions From Gold Mining

NASA Astrophysics Data System (ADS)

Strode, S. A.; Jaeglé, L.; Selin, N. E.; Sunderland, E.

2007-12-01

Mercury emissions from both historic gold and silver mining and modern small-scale gold mining are highly uncertain. Historic mercury emissions can affect the modern atmosphere through reemission from land and ocean, and quantifying mercury emissions from historic gold and silver mining can help constrain modern mining sources. While estimates of mercury emissions during historic gold rushes exceed modern anthropogenic mercury emissions in North America, sediment records in many regions do not show a strong gold rush signal. We use the GEOS-Chem chemical transport model to determine the spatial footprint of mercury emissions from mining and compare model runs from gold rush periods to sediment and ice core records of historic mercury deposition. Based on records of gold and silver production, we include mercury emissions from North and South American mining of 1900 Mg/year in 1880, compared to modern global anthropogenic emissions of 3400 Mg/year. Including this large mining source in GEOS-Chem leads to an overestimate of the modeled 1880 to preindustrial enhancement ratio compared to the sediment core record. We conduct sensitivity studies to constrain the level of mercury emissions from modern and historic mining that is consistent with the deposition records for different regions.

Shape memory alloy thaw sensors

DOEpatents

Shahinpoor, M.; Martinez, D.R.

1998-04-07

A sensor permanently indicates that it has been exposed to temperatures exceeding a critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures above the austenitic temperature of the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states. 16 figs.

Shape memory alloy thaw sensors

DOEpatents

Shahinpoor, Mohsen; Martinez, David R.

1998-01-01

A sensor permanently indicates that it has been exposed to temperatures exceeding a critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures above the Austenitic temperature of the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states.

Measuring Holocene Indian Summer Monsoon Precipitation through Lake Sedimentary Proxies, Eastern Tibet

NASA Astrophysics Data System (ADS)

Perello, M. M.; Bird, B. W.; Lei, Y.; Polissar, P. J.; Thompson, L. G.; Yao, T.

2017-12-01

The Tibetan Plateau is the headwaters of several major river systems in South Asia, which serve as essential water resources for more than 40% of the world's population. The majority of regional precipitation that sustains these water resources is from the Indian summer monsoon (ISM), which can experience considerably variability in response to local and remote forcings and teleconnections. Despite the ISM's importance, its sensitivity to long term and abrupt changes in climatic boundary conditions is not well established with the modern instrumental record or the available body of paleoclimate data. Here, we present results from an ongoing study that utilizes lake sediment records to provide a longer record of relative levels of precipitation and lake level during the monsoon season. The sediments cores used in this study were collected from five lakes along an east-west transect in the Eastern Tibetan Plateau (87-95°E). Using these records, we assess temporal and spatial variability in the intensity of the ISM throughout the Holocene on decadal frequencies. Multiple proxies, including sedimentology, grain size, geochemistry, terrestrial and aquatic leaf wax isotopes, and diatom community assemblages, are used to assess paleo-precipitation and lake level. Preliminary records from our lakes indicate regional trends in monsoon strength, with higher lake levels in the Early Holocene, but with greater variability in the Late Holocene than in other regional paleoclimate records. We have also observed weak responses in our lakes to the Late Holocene events, the Medieval Climate Anomaly and the Little Ice Age. These paleoclimate reconstructions furthers our understanding of strong versus weak monsoon intensities and can be incorporated in climate models for predicting future monsoon conditions.

Barriers to Modern Contraceptive Use in Kinshasa, DRC.

PubMed

Muanda, Mbadu; Gahungu Ndongo, Parfait; Taub, Leah D; Bertrand, Jane T

2016-01-01

Recent research from Kinshasa, DRC, has shown that only one in five married women uses modern contraception; over one quarter have an unmet need for family planning; and almost 400 health facilities across Kinshasa report that they provide modern contraception. This study addresses the question: with reasonable physical access and relatively high unmet need, why is modern contraceptive prevalence so low? To this end, the research team conducted 6 focus groups of women (non-users of any method, users of traditional methods, and users of modern methods) and 4 of husbands (of users of traditional methods and in non-user unions) in health zones with relatively strong physical access to FP services. Five key barriers emerged from the focus group discussions: fear of side effects (especially sterility), costs of the method, sociocultural norms (especially the dominant position of the male in family decision-making), pressure from family members to avoid modern contraception, and lack of information/misinformation. These findings are very similar to those from 12 other studies of sociocultural barriers to family planning in sub-Saharan Africa. Moreover, they have strong programmatic implications for the training of FP workers to counsel future clients and for the content of behavior change communication interventions.

The origins of modern divorce.

PubMed

Coontz, Stephanie

2007-03-01

High rates of marital dissolution and easy access to divorce are not unprecedented, historically or cross-culturally. But contemporary divorce in North America and Western Europe has different origins and features than divorce in previous cultures. The origins of modern divorce patterns date back more than 200 years, to the invention of the historically unprecedented idea that marriage should be based on love and mutual affection. Ironically, then, the fragility of modern marriage stems from the same values that have elevated the marital relationship above all other personal and familial commitments: the concentration of emotion, passion, personal identity, and self-validation in the couple relationship and the attenuation of emotional attachments and obligations beyond the conjugal unit. The immediate causes of divorce may range from factors as diverse as the personal psychological characteristics of one or both spouses to the stresses of economic hardship and community disintegration. But in a larger perspective, the role of divorce in modern societies and its relatively high occurrence both flow from the same complex of factors that have made good marriages so much more central to people's happiness than through most of the past, and deterioration of a marital relationship so much more traumatic.

Does Southern Ocean Surface Forcing Shape the Global Ocean Overturning Circulation?

NASA Astrophysics Data System (ADS)

Sun, Shantong; Eisenman, Ian; Stewart, Andrew L.

2018-03-01

Paleoclimate proxy data suggest that the Atlantic Meridional Overturning Circulation (AMOC) was shallower at the Last Glacial Maximum (LGM) than its preindustrial (PI) depth. Previous studies have suggested that this shoaling necessarily accompanies Antarctic sea ice expansion at the LGM. Here the influence of Southern Ocean surface forcing on the AMOC depth is investigated using ocean-only simulations from a state-of-the-art climate model with surface forcing specified from the output of previous coupled PI and LGM simulations. In contrast to previous expectations, we find that applying LGM surface forcing in the Southern Ocean and PI surface forcing elsewhere causes the AMOC to shoal only about half as much as when LGM surface forcing is applied globally. We show that this occurs because diapycnal mixing renders the Southern Ocean overturning circulation more diabatic than previously assumed, which diminishes the influence of Southern Ocean surface buoyancy forcing on the depth of the AMOC.

Fundamentals--Rudolf Virchow and modern medicine.

PubMed Central

Reese, D M

1998-01-01

The 19th century pathologist Rudolf Virchow was a physician, scientist, and revolutionary. The preeminent medical investigator of his day, Virchow remains best-known for his theory of cellular pathology, which laid the conceptual foundation for modern scientific medicine. Less appreciated are Virchow's numerous accomplishments in public health, anthropology, and European politics, including his quest for social justice and democracy in Imperial Germany. The study of Virchow's life and writings may provide contemporary physicians with a powerful role model as we grapple with the complexities of the modern medical enterprise. PMID:9735691

Searching for signatures of cold adaptations in modern and archaic humans: hints from the brown adipose tissue genes

PubMed Central

Sazzini, M; Schiavo, G; De Fanti, S; Martelli, P L; Casadio, R; Luiselli, D

2014-01-01

Adaptation to low temperatures has been reasonably developed in the human species during the colonization of the Eurasian landmass subsequent to Out of Africa migrations of anatomically modern humans. In addition to morphological and cultural changes, also metabolic ones are supposed to have favored human isolation from cold and body heat production and this can be hypothesized also for most Neandertal and at least for some Denisovan populations, which lived in geographical areas that strongly experienced the last glacial period. Modulation of non-shivering thermogenesis, for which adipocytes belonging to the brown adipose tissue are the most specialized cells, might have driven these metabolic adaptations. To perform an exploratory analysis aimed at looking into this hypothesis, variation at 28 genes involved in such functional pathway was investigated in modern populations from different climate zones, as well as in Neandertal and Denisovan genomes. Patterns of variation at the LEPR gene, strongly related to increased heat dissipation by mitochondria, appeared to have been shaped by positive selection in modern East Asians, but not in Europeans. Moreover, a single potentially cold-adapted LEPR allele, different from the supposed adaptive one identified in Homo sapiens, was found also in Neandertal and Denisovan genomes. These findings suggest that independent mechanisms for cold adaptations might have been developed in different non-African human groups, as well as that the evolution of possible enhanced thermal efficiency in Neandertals and in some Denisovan populations has plausibly entailed significant changes also in other functional pathways than in the examined one. PMID:24667833

Analytical description of the modern steam automobile

NASA Technical Reports Server (NTRS)

Peoples, J. A.

1974-01-01

The sensitivity of operating conditions upon performance of the modern steam automobile is discussed. The word modern has been used in the title to indicate that emphasis is upon miles per gallon rather than theoretical thermal efficiency. This has been accomplished by combining classical power analysis with the ideal Pressure-Volume diagram. Several parameters are derived which characterize performance capability of the modern steam car. The report illustrates that performance is dictated by the characteristics of the working medium, and the supply temperature. Performance is nearly independent of pressures above 800 psia. Analysis techniques were developed specifically for reciprocating steam engines suitable for automotive application. Specific performance charts have been constructed on the basis of water as a working medium. The conclusions and data interpretation are therefore limited within this scope.

Discussion of “Deglacial paleoclimate in the southwestern United States: an abrupt 18.6 cold event and evidence for a North Atlantic forcing of Termination I” by M.S. Lachniet, Y. Asmerom and V. Polyak

USGS Publications Warehouse

Winograd, Isaac J.

2012-01-01

Utilizing a stable isotopic time series obtained from a speleothem (PC-1), which grew between 20.1 and 15.6 ka, Lachniet, Asmeron and Polyak (2011; hereafter LAP) present evidence for a significant cold event in the southern Great Basin at 18.6 ka, a finding that we accept. Supplementing this short record with a literature review, they go on to claim, as their central thesis, that the paleoclimate of the southwestern US was driven by “the transmission of atmospheric anomalies to the southwest…that coincided with deglacial climate changes in Greenland and the North Atlantic region”, not by a “dominant Pacific Ocean SST control” as suggested by SST time series off California and by the Devils Hole δ18O time series from the southern Great Basin. We do not find their central thesis supportable.

Self-shaping of bioinspired chiral composites

NASA Astrophysics Data System (ADS)

Rong, Qing-Qing; Cui, Yu-Hong; Shimada, Takahiro; Wang, Jian-Shan; Kitamura, Takayuki

2014-08-01

Self-shaping materials such as shape memory polymers have recently drawn considerable attention owing to their high shape-changing ability in response to changes in ambient conditions, and thereby have promising applications in the biomedical, biosensing, soft robotics and aerospace fields. Their design is a crucial issue of both theoretical and technological interest. Motivated by the shape-changing ability of Towel Gourd tendril helices during swelling/deswelling, we present a strategy for realizing self-shaping function through the deformation of micro/nanohelices. To guide the design and fabrication of self-shaping materials, the shape equations of bent configurations, twisted belts, and helices of slender chiral composite are developed using the variation method. Furthermore, it is numerically shown that the shape changes of a chiral composite can be tuned by the deformation of micro/nanohelices and the fabricated fiber directions. This work paves a new way to create self-shaping composites.

Echinocyte shapes: bending, stretching, and shear determine spicule shape and spacing.

PubMed Central

Mukhopadhyay, Ranjan; Lim H W, Gerald; Wortis, Michael

2002-01-01

We study the shapes of human red blood cells using continuum mechanics. In particular, we model the crenated, echinocytic shapes and show how they may arise from a competition between the bending energy of the plasma membrane and the stretching/shear elastic energies of the membrane skeleton. In contrast to earlier work, we calculate spicule shapes exactly by solving the equations of continuum mechanics subject to appropriate boundary conditions. A simple scaling analysis of this competition reveals an elastic length Lambda(el), which sets the length scale for the spicules and is, thus, related to the number of spicules experimentally observed on the fully developed echinocyte. PMID:11916836

Universality of fragment shapes

PubMed Central

Domokos, Gábor; Kun, Ferenc; Sipos, András Árpád; Szabó, Tímea

2015-01-01

The shape of fragments generated by the breakup of solids is central to a wide variety of problems ranging from the geomorphic evolution of boulders to the accumulation of space debris orbiting Earth. Although the statistics of the mass of fragments has been found to show a universal scaling behavior, the comprehensive characterization of fragment shapes still remained a fundamental challenge. We performed a thorough experimental study of the problem fragmenting various types of materials by slowly proceeding weathering and by rapid breakup due to explosion and hammering. We demonstrate that the shape of fragments obeys an astonishing universality having the same generic evolution with the fragment size irrespective of materials details and loading conditions. There exists a cutoff size below which fragments have an isotropic shape, however, as the size increases an exponential convergence is obtained to a unique elongated form. We show that a discrete stochastic model of fragmentation reproduces both the size and shape of fragments tuning only a single parameter which strengthens the general validity of the scaling laws. The dependence of the probability of the crack plan orientation on the linear extension of fragments proved to be essential for the shape selection mechanism. PMID:25772300

Odd Shape Out

ERIC Educational Resources Information Center

Cady, Jo Ann; Wells, Pamela

2016-01-01

The Odd Shape Out task was an open-ended problem that engaged students in comparing shapes based on their properties. Four teachers submitted the work of 116 students from across the country. This article compares various student's responses to the task. The problem allowed for differentiation, as shown by the many different ways that students…

Sawtooth oscillations in shaped plasmas

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

Lazarus, E. A.; Luce, T. C.; Burrell, K. H.

The role of interchange and internal kink modes in the sawtooth oscillations is explored by comparing bean- and oval-shaped plasmas. The n=1 instability that results in the collapse of the sawtooth has been identified as a quasi-interchange in the oval cases and the internal kink in the bean shape. The ion and electron temperature profiles are followed in detail through the sawtooth ramp. It is found that electron energy transport rates are very high in the oval and quite low in the bean shape. Ion energy confinement in the oval is excellent and the sawtooth amplitude ({delta}T/T) in the ionmore » temperature is much larger than that of the electrons. The sawtooth amplitudes for ions and electrons are comparable in the bean shape. The measured q profiles in the bean and oval shapes are found to be consistent with neoclassical current diffusion of the toroidal current, and the observed differences in q largely result from the severe differences in electron energy transport. For both shapes the collapse flattens the q profile and after the collapse return to q{sub 0} > or approx. 1. Recent results on intermediate shapes are reported. These shapes show that the electron energy transport improves gradually as the plasma triangularity is increased.« less

Cenozoic sea level and the rise of modern rimmed atolls

USGS Publications Warehouse

Toomey, Michael; Ashton, Andrew; Raymo, Maureen E.; Perron, J. Taylor

2016-01-01

Sea-level records from atolls, potentially spanning the Cenozoic, have been largely overlooked, in part because the processes that control atoll form (reef accretion, carbonate dissolution, sediment transport, vertical motion) are complex and, for many islands, unconstrained on million-year timescales. Here we combine existing observations of atoll morphology and corelog stratigraphy from Enewetak Atoll with a numerical model to (1) constrain the relative rates of subsidence, dissolution and sedimentation that have shaped modern Pacific atolls and (2) construct a record of sea level over the past 8.5 million years. Both the stratigraphy from Enewetak Atoll (constrained by a subsidence rate of ~ 20 m/Myr) and our numerical modeling results suggest that low sea levels (50–125 m below present), and presumably bi-polar glaciations, occurred throughout much of the late Miocene, preceding the warmer climate of the Pliocene, when sea level was higher than present. Carbonate dissolution through the subsequent sea-level fall that accompanied the onset of large glacial cycles in the late Pliocene, along with rapid highstand constructional reef growth, likely drove development of the rimmed atoll morphology we see today.

Effect of shaping sensor data on pilot response

NASA Technical Reports Server (NTRS)

Bailey, Roger M.

1990-01-01

The pilot of a modern jet aircraft is subjected to varying workloads while being responsible for multiple, ongoing tasks. The ability to associate the pilot's responses with the task/situation, by modifying the way information is presented relative to the task, could provide a means of reducing workload. To examine the feasibility of this concept, a real time simulation study was undertaken to determine whether preprocessing of sensor data would affect pilot response. Results indicated that preprocessing could be an effective way to tailor the pilot's response to displayed data. The effects of three transformations or shaping functions were evaluated with respect to the pilot's ability to predict and detect out-of-tolerance conditions while monitoring an electronic engine display. Two nonlinear transformations, on being the inverse of the other, were compared to a linear transformation. Results indicate that a nonlinear transformation that increases the rate-or-change of output relative to input tends to advance the prediction response and improve the detection response, while a nonlinear transformation that decreases the rate-of-change of output relative to input tends to lengthen the prediction response and make detection more difficult.

Negotiating the Gay Male Stereotype in Ballet and Modern Dance

ERIC Educational Resources Information Center

Polasek, Katherine M.; Roper, Emily A.

2011-01-01

Dance, ballet and modern in particular, is culturally defined as a feminine activity in the United States. The purpose of the present study was to examine the experiences of professional male modern and ballet dancers in the United States. Semi-structured interviews were conducted with 12 current professional ballet and modern dancers. We examined…

Modernizing the Federal Government: Paying for Performance

DTIC Science & Technology

2007-01-01

works (Barr, 2007d). Employees are rated on performance measures such as “fair and equitable treatment of taxpayers” and “customer satisfaction ... Performance Act of 2007, Senate bill 1046, Washington, D.C., 2007b. 38 Modernizing the Federal Government: Paying for Performance Vroom , Victor H...AND SUBTITLE Modernizing the federal government paying for performance 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR

A Computational Model of Multidimensional Shape

PubMed Central

Liu, Xiuwen; Shi, Yonggang; Dinov, Ivo

2010-01-01

We develop a computational model of shape that extends existing Riemannian models of curves to multidimensional objects of general topological type. We construct shape spaces equipped with geodesic metrics that measure how costly it is to interpolate two shapes through elastic deformations. The model employs a representation of shape based on the discrete exterior derivative of parametrizations over a finite simplicial complex. We develop algorithms to calculate geodesics and geodesic distances, as well as tools to quantify local shape similarities and contrasts, thus obtaining a formulation that accounts for regional differences and integrates them into a global measure of dissimilarity. The Riemannian shape spaces provide a common framework to treat numerous problems such as the statistical modeling of shapes, the comparison of shapes associated with different individuals or groups, and modeling and simulation of shape dynamics. We give multiple examples of geodesic interpolations and illustrations of the use of the models in brain mapping, particularly, the analysis of anatomical variation based on neuroimaging data. PMID:21057668

A Modern Periodic Table.

ERIC Educational Resources Information Center

Herrenden-Harker, B. D.

1997-01-01

Presents a modern Periodic Table based on the electron distribution in the outermost shell and the order of filling of the sublevels within the shells. Enables a student to read off directly the electronic configuration of the element and the order in which filling occurs. (JRH)

Practical Development of Modern Mass Media Education in Poland

ERIC Educational Resources Information Center

Fedorov, Alexander

2012-01-01

Practical development of modern mass media education in Poland. The paper analyzes the main ways of practical development of modern media education (1992-2012 years) in Poland: basic technologies, main events, etc.

The Isotopic Composition of Mammal Teeth Across South America: A Proxy for Paleoclimate and Paleoelevation of the Altiplano

NASA Astrophysics Data System (ADS)

Bershaw, J.; Garzione, C. N.; Higgins, P.; MacFadden, B. J.; Anaya, F.; Alvaregna, H. M. F.

2006-12-01

Paleoelevation constraints from stable isotopes of sedimentary carbonate suggest that significant surface uplift of the northern Andean Altiplano, on the order of 2.5 to 3.5 km, occurred between ~10.3 and 6.8 Ma (Garzione et al., 2006; Ghosh et al., 2006). Better spatial and temporal constraints on paleoelevation of the Altiplano is key to understanding potential tectonic forcing mechanisms of rapid surface uplift. Our research focuses on mammal tooth enamel because it preserves an essentially continuous record of climate and environment for a portion of the animal's life. Because the effects of diagenesis can be more easily identified in tooth enamel, analysis of fossil teeth provides a reliable record of the isotopic composition of surface water that the animal ingested. Studies have shown that the isotopic abundance of heavy oxygen (δ18O) in modern rainfall decreases systematically with increasing elevations across Bolivia (Gonfiantini, 2001). Here, we present new stable isotope data from mammal teeth spanning ~26.5 Ma to present, collected from the Altiplano of Bolivia and lowland Brazil. Results show substantially more positive isotopic compositions of oxygen δ18O for late Oligocene tooth samples when compared to modern tooth δ18O values, both collected from high elevation sites on the Altiplano. Late Oligocene teeth collected from low elevation sites in southeast Brazil show δ18O values similar to contemporaneous teeth collected at high elevation on the Altiplano (within 2‰). This suggests that at least part of the Altiplano was at low elevation during the late Oligocene. In addition, precipitation over the Altiplano may have been sourced from the Pacific during the late Oligocene to account for the absence of δ18O depletion typical of water vapor that has traversed the continent from east to west. Comparing the northern and southern Altiplano in late Miocene time, 6 to 9 Ma teeth show δ18O values similar to modern teeth collected nearby, with much

Shape-Morphing Nanocomposite Origami

PubMed Central

2015-01-01

Nature provides a vast array of solid materials that repeatedly and reversibly transform in shape in response to environmental variations. This property is essential, for example, for new energy-saving technologies, efficient collection of solar radiation, and thermal management. Here we report a similar shape-morphing mechanism using differential swelling of hydrophilic polyelectrolyte multilayer inkjets deposited on an LBL carbon nanotube (CNT) composite. The out-of-plane deflection can be precisely controlled, as predicted by theoretical analysis. We also demonstrate a controlled and stimuli-responsive twisting motion on a spiral-shaped LBL nanocomposite. By mimicking the motions achieved in nature, this method offers new opportunities for the design and fabrication of functional stimuli-responsive shape-morphing nanoscale and microscale structures for a variety of applications. PMID:24689908

Modern and Contemporary Cultural Heritage Documentation and Knowledge by Surveying and its Representation

NASA Astrophysics Data System (ADS)

Balletti, C.; Costa, M.; Guerra, F.; Martinello, F.; Vernier, P.

2018-05-01

Conservation of modern and contemporary cultural heritage, which goes from design objects, to architecture, to cities and territories, is certainly a current topic and in the development phase as it is underway - in the same modernity - a process of systematic replacement of architectural elements, outcome of solutions then experimental, which today are reproduced with contemporary materials, analogous in the appearance, but intimately different especially in the technological content.The paper describes the particular case of La Tour de Meudon, better known as The Tower, (1966) by André Bloc, a contemporary architect of Le Corbusier, founder of L'Architecture d'aujourd'hui, who created his habitable sculptures. All his works mark the evolution of geometric abstraction to the free form, and they are still admirable testimonies of a journey that led him from architecture to architecture. His Architecture and his sculpture intertwine, opening the plastic unity of form in physical space-time. The survey is a fundamental moment for the knowledge of these hybrid architectures, where the structural component is hidden by its evident plasticity, as if it were a large sculpture with abstract and overlapping geometric shapes.Survey isn't only an analysis of geometries: it is instrumental to the other structural and material analyses since it provides a metric and topological basis on which to spatially locate the phenomena being studied. The integrated survey of the building (laser scanning, photogrammetry, topography) has allowed to document his project, contributing to the to definition of the actual construction characteristics and ascertain both the material consistency and the state of conservation.