Science.gov

Sample records for regional radiocarbon disparities

  1. Radiocarbon

    NASA Astrophysics Data System (ADS)

    Broecker, W. S.

    2003-12-01

    Willard Libby's invention of the radiocarbon dating method revolutionized the fields of archeology and Quaternary geology because it brought into being a means to correlate events that occurred during the past 3.5×104 years on a planet-wide scale (Libby et al., 1949). This contribution was recognized with the award of the Nobel Prize for Chemistry. In addition, radiocarbon measurements have been a boon to the quantification of many processes taking place in the environment, to name a few: the rate of "ventilation" of the deep ocean, the turnover time of humus in soils, the rate of growth of cave deposits, the source of carbon-bearing atmospheric particulates, the rates of gas exchange between the atmosphere and water bodies, the replacement time of carbon atoms in human tissue, and depths of bioturbation in marine sediment. Some of these applications have been greatly aided by the creation of excess 14C atoms as the result of nuclear tests conducted in the atmosphere. Since the 1960s, this so-called bomb radiocarbon has made its way into all of the Earth's active carbon reservoirs. To date, tens of thousands of radiocarbon measurements have been made in laboratories throughout the world.

  2. Child poverty and regional disparities in Turkey.

    PubMed

    Eryurt, Mehmet Ali; Koç, Ismet

    2013-01-01

    The United Nations Children's Fund (UNICEF) defines child poverty as the inability of the child to realize their existing potential due to their inability to access resources across different dimensions of life (income, health, nutrition, education, environment, etc.). On the basis of this definition, an attempt has been made in this study to put forth the disadvantaged positions children have in different dimensions of their lives, specifically by taking regional disparities into account. As the data source, the Turkey Demographic and Health Survey 2008 is used, a survey that consists of detailed information about the different dimensions of child poverty. In this study, in order to measure poverty in four different dimensions (education and work, health and nutrition, family environment, and domestic environment), a total of 25 variables were used and descriptive and multivariate analyses were made in order to highlight the regional disparities in child poverty. Principle components analysis conducted through the use of a deficit approach reveals that the variables closely related with education and health and nutrition were the critical dimensions behind child poverty in Turkey. The results of this study indicate that 22.4% of children in Turkey are poor when various dimensions of life are taken into account; the region with the highest child poverty is Central East Anatolia, at 34.9%, while the region with the lowest rate is East Marmara, at 15.6%.

  3. Investigating the influence of regional climate and oceanography on marine radiocarbon reservoir ages in southwest New Zealand

    NASA Astrophysics Data System (ADS)

    Hinojosa, Jessica L.; Moy, Christopher M.; Prior, Christine A.; Eglinton, Timothy I.; McIntyre, Cameron P.; Stirling, Claudine H.; Wilson, Gary S.

    2015-12-01

    The New Zealand fjords are located at a latitude where distinct oceanic and atmospheric fronts separate carbon reservoirs of varying residence time. The marine radiocarbon reservoir age in this region is likely to deviate from the global average reservoir age over space and time as frontal boundaries migrate north and south. Here we present new estimates of modern radiocarbon reservoir age using the radiocarbon content of bivalve shells collected live before 1950. Multiple measurements from hydrographically distinct sites support the use of a ΔR, defined as the regional offset between measured and modeled marine radiocarbon reservoir age, of 59 ± 35 years for the New Zealand fjords. We also assess the radiocarbon content of bulk surface sediments throughout the fjord region. Sediment with a higher proportion of marine organic carbon has relatively less radiocarbon than more terrestrial sediment, suggesting a short residence time of organic carbon on land before deposition in the fjords. Additionally, we constrain reservoir age variability throughout the Holocene using coeval terrestrial and marine macrofossils. Although our modern results suggest spatial consistency in ΔR throughout the fjords, large deviations from the global average marine radiocarbon reservoir age exist in the paleo record. We find four ancient ΔR values, extending back to ˜10.2 cal kyr BP, to be negative or near zero. A likely cause of younger radiocarbon reservoir ages at select intervals throughout the Holocene is the increased influence of the Southern Hemisphere westerly winds, which cause extreme precipitation in the region that delivers terrestrial carbon, enriched in radiocarbon, to fjord basins. However, bivalve depth habitat may also influence radiocarbon content due to a stratified water column containing distinct carbon pools. This work highlights the need for thorough assessment of local radiocarbon cycling in similar regions of dynamic ocean/atmosphere frontal zones

  4. Assessing the regional disparities in geoengineering impacts

    NASA Astrophysics Data System (ADS)

    Irvine, Peter J.; Ridgwell, Andy; Lunt, Daniel J.

    2010-09-01

    Solar Radiation Management (SRM) Geoengineering may ameliorate many consequences of global warming but also has the potential to drive regional climates outside the envelope of greenhouse-gas induced warming, creating ‘novel’ conditions, and could affect precipitation in some regions disproportionably. Here, using a fully coupled climate model we explore some new methodologies for assessing regional disparities in geoengineering impacts. Taking a 4 × CO2 climate and an idealized ‘sunshade’ SRM strategy, we consider different fractions of the maximum theoretical, 4 × CO2-cancelling global mean cooling. Whilst regional predictions in particularly relatively low resolution global climate models must be treated with caution, our simulations indicate that it might be possible to identify a level of SRM geoengineering capable of meeting multiple targets, such as maintaining a stable mass balance of the Greenland ice sheet and cooling global climate, but without reducing global precipitation below pre-industrial or exposing significant fractions of the Earth to ‘novel’ climate conditions.

  5. Assessing the Regional Disparities in Geoengineering impacts

    NASA Astrophysics Data System (ADS)

    Irvine, P. J.; Ridgwell, A. J.; Lunt, D. J.

    2010-12-01

    maintaining a stable mass balance of the Greenland ice sheet and cooling global climate, but without reducing global precipitation below pre-industrial or exposing significant fractions of the Earth to ‘novel’ climate conditions [Irvine et al., 2009]. The HadCM3L simulations carried out for this work include a pre-industrial control, a simulation with 4xCO2, and 10 simulations with 4xCO2 and different levels of SRM geoengineering ranging from 10% to 100% of a full intervention sufficient to cool the climate to pre-industrial average surface air temperature. Cox, P. M., R. A. Betts, C. D. Jones, S. A. Spall, and I. J. Totterdell (2000), Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model, Nature, 408(6809), 184-187. Govindasamy, B., K. Caldeira, and P. B. Duffy (2003), Geoengineering Earth's radiation balance to mitigate climate change from a quadrupling of CO2, Global and Planetary Change, 37(1-2), 157-168. Irvine, P. J., D. J. Lunt, E. J. Stone, and A. Ridgwell (2009), The fate of the Greenland Ice Sheet in a geoengineered, high CO2 world, Environmental Research Letters, 4(4). Irvine, P., A. Ridgwell, and D. Lunt (2010), Assessing the Regional Disparities in Geoengineering Impacts, Geophys. Res. Lett., doi:10.1029/2010GL044447, in press

  6. Regional Disparities in Educational Development: Diagnosis and Policies for Reduction.

    ERIC Educational Resources Information Center

    Carron, Gabriel, Ed.; Chau, Ta Ngoc, Ed.

    Four lengthy papers and an introduction discuss case studies of regional disparities in educational development in Cameroon, Madagascar, Kenya, Tanzania, and Thailand. In considering the specific political and socioeconomic contexts of these countries, the papers focus on methods of both analyzing the causes of disparities and reducing the…

  7. Regional Disparities in Educational Development: Diagnosis and Policies for Reduction.

    ERIC Educational Resources Information Center

    Carron, Gabriel, Ed.; Chau, Ta Ngoc, Ed.

    Four lengthy papers and an introduction discuss case studies of regional disparities in educational development in Cameroon, Madagascar, Kenya, Tanzania, and Thailand. In considering the specific political and socioeconomic contexts of these countries, the papers focus on methods of both analyzing the causes of disparities and reducing the…

  8. Economic Disparities and Life Satisfaction in European Regions

    ERIC Educational Resources Information Center

    Pittau, M. Grazia; Zelli, Roberto; Gelman, Andrew

    2010-01-01

    This paper investigates the role of economic variables in predicting regional disparities in reported life satisfaction of European Union (EU) citizens. European subnational units (regions) are defined according to the first-level EU nomenclature of territorial units. We use multilevel modeling to explicitly account for the hierarchical nature of…

  9. Economic Disparities and Life Satisfaction in European Regions

    ERIC Educational Resources Information Center

    Pittau, M. Grazia; Zelli, Roberto; Gelman, Andrew

    2010-01-01

    This paper investigates the role of economic variables in predicting regional disparities in reported life satisfaction of European Union (EU) citizens. European subnational units (regions) are defined according to the first-level EU nomenclature of territorial units. We use multilevel modeling to explicitly account for the hierarchical nature of…

  10. New radiocarbon dates for Columbian mammoth and Mexican horse from southern Alberta and the Lateglacial regional fauna

    NASA Astrophysics Data System (ADS)

    Hills, Leonard V.; Harington, C. Richard

    2003-06-01

    New radiocarbon dates on Columbian mammoth ( Mammuthus columbi) and Mexican horse ( Equus conversidens) specimens from southern Alberta are 10,930±100 BP and 10,870±45 years BP, respectively—older than originally thought. These specimens are reviewed in the light of 10 other sites in southern Alberta that have yielded large mammal remains radiocarbon dated to about 11,000 BP. Thus, the regional fauna includes at least 11 mammalian species. This fauna was not restricted to the foothills, but extended well onto the plains and may prove useful in correlating foothills terraces with those of the plains.

  11. Reduction of Regional Disparities: The Role of Educational Planning.

    ERIC Educational Resources Information Center

    Carron, Gabriel; Chau, Ta Ngoc

    Based on eight monographs presented and discussed at a working meeting of the International Institute for Educational Planning (IIEP) in 1977, this summational report is intended to be used by educational planners for a reduction of regional disparities through school network reorganization and improvements in educational service. Part I discusses…

  12. Epidemiology, trends, and disparities in regional anaesthesia for orthopaedic surgery.

    PubMed

    Cozowicz, C; Poeran, J; Memtsoudis, S G

    2015-12-01

    Recent studies have linked the use of regional anaesthesia to improved outcomes. Epidemiological research on utilization, trends, and disparities in this field is sparse; however, large nationally representative database constructs containing anaesthesia-related data, demographic information, and multiyear files are now available. Together with advances in research methodology and technology, these databases provide the foundation for epidemiological research in anaesthesia. We present an overview of selected studies that provide epidemiological data and describe current anaesthetic practice, trends, and disparities in orthopaedic surgery in particular. This literature suggests that that even among orthopaedic surgical procedures, which are highly amenable to regional anaesthetic techniques, neuraxial anaesthetics and peripheral nerve blocks are used in only a minority of procedures. Trend analyses show that peripheral nerve blocks are gaining in popularity, whereas use of neuraxial anaesthetics is remaining relatively unchanged or even declining over time. Finally, significant disparities and variability in anaesthetic care seem to exist based on demographic and health-care-related factors. With anaesthesia playing an increasingly important part in population-based health-care delivery and evidence indicating improved outcome with use of regional anaesthesia, more research in this area is needed. Furthermore, prevalent disparities and variabilities in anaesthesia practice need to be specified further and addressed in the future. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. High-resolution regional modelling of natural and anthropogenic radiocarbon in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Ayache, Mohamed; Dutay, Jean-Claude; Mouchet, Anne; Tisnérat-Laborde, Nadine; Montagna, Paolo; Tanhua, Toste; Siani, Giuseppe; Jean-Baptiste, Philippe

    2017-03-01

    A high-resolution dynamical model (Nucleus for European Modelling of the Ocean, Mediterranean configuration - NEMO-MED12) was used to give the first simulation of the distribution of radiocarbon (14C) across the whole Mediterranean Sea. The simulation provides a descriptive overview of both the natural pre-bomb 14C and the entire anthropogenic radiocarbon transient generated by the atmospheric bomb tests performed in the 1950s and early 1960s. The simulation was run until 2011 to give the post-bomb distribution. The results are compared to available in situ measurements and proxy-based reconstructions. The radiocarbon simulation allows an additional and independent test of the dynamical model, NEMO-MED12, and its performance to produce the thermohaline circulation and deep-water ventilation. The model produces a generally realistic distribution of radiocarbon when compared with available in situ data. The results demonstrate the major influence of the flux of Atlantic water through the Strait of Gibraltar on the inter-basin natural radiocarbon distribution and characterize the ventilation of intermediate and deep water especially through the propagation of the anthropogenic radiocarbon signal. We explored the impact of the interannual variability on the radiocarbon distribution during the Eastern Mediterranean Transient (EMT) event. It reveals a significant increase in 14C concentration (by more than 60 ‰) in the Aegean deep water and at an intermediate level (value up to 10 ‰) in the western basin. The model shows that the EMT makes a major contribution to the accumulation of radiocarbon in the eastern Mediterranean deep waters.

  14. Radiocarbon Dating

    SciTech Connect

    Buchholz, B A

    2007-12-20

    Radiocarbon dating can be used to determine the age of objects that contain components that were once alive. In the case of human remains, a radiocarbon date can distinguish between a crime scene and an archeological site. Documents, museum artifacts and art objects can be dated to determine if their age is correct for the historical context. A radiocarbon date does not confirm authenticity, but it can help identify a forgery.

  15. Utility of radiocarbon-dated stratigraphy in determining late Holocene earthquake recurrence intervals, upper Cook Inlet region, Alaska

    USGS Publications Warehouse

    Bartsch-Winkler, S.; Schmoll, H.R.

    1992-01-01

    During the great 1964 earthquake, parts of coastal southern Alaska subsided tectonically as much as 2 m, and this led to burial of high-intertidal organic-rich marshes by low-intertidal and tidal silt. In the tectonically active parts of upper Cook Inlet, the presence of stratigraphic sections containing numerous prehistoric interbedded layers of peat and silt suggests that such stratigraphy resulted when marshes and forests were similarly inundated and buried by intertidal and tidal sediment as a result of great, prehistoric earthquakes. This study tests the feasibility of using buried, radiocarbon-dated, late Holocene peat layers that are exposed in the intertidal zone of upper Cook Inlet to determine earthquake recurrence intervals. Because of problems associated with conventional radiocarbon dating, the complex stratigraphy of the study area, the tectonic setting, and regional changes in sea level, conclusions from the study do not permit precise identification of the timing and recurrence of paleoseismic events. -from Authors

  16. Simulation of bombe radiocarbon transient in the Mediterranean Sea using a high-resolution regional model.

    NASA Astrophysics Data System (ADS)

    Ayache, Mohamed; Dutay, Jean-claude; Mouchet, Anne; Tisnérat-Laborde, Nadine; Houma-Bachari, Fouzia; Louanchi, Ferial; jean-baptiste, Philippe

    2016-04-01

    The radiocarbon isotope of carbon "14C", which a half-life of 5730 years, is continually formed naturally in the atmosphere by the neutron bombardment of 14N atoms. However, in the 1950s and early1960s, the atmospheric testing of thermonuclear weapons added a large amount of 14C into the atmosphere. The gradual infusion and spread of this "bomb" 14C through the oceans has provided a unique opportunity to gain insight into the specific rates characterizing the carbon cycle and ocean ventilations on such timescales. This numerical study provides, for the first time in the Mediterranean Sea, a simulation of the anthropogenic 14C invasion covers a 70-years period spanning the entire 14C generated by the bomb test, by using a high resolution regional model NEMO-MED12 (1/12° of horizontal resolution). This distribution and evolution of Δ14C of model is compared with recent high resolution 14C measurements obtained from surface water corals (Tisnérat-Laborde et al, 2013). In addition to providing constraints on the air-sea transfer of 14C, our work provides information on the thermohaline circulation and the ventilation of the deep waters to constrain the degree to which the NEMO-MED12 can reproduce correctly the main hydrographic features of the Mediterranean Sea circulation and its variations estimated from corals 14C time series measurements. This study is part of the work carried out to assess the robustness of the NEMO-MED12 model, which will be used to study the evolution of the climate and its effect on the biogeochemical cycles in the Mediterranean Sea, and to improve our ability to predict the future evolution of the Mediterranean Sea under the increasing anthropogenic pressure.

  17. Radiocarbon dating of fossil mollusk shells in the Yucca Mountain region

    SciTech Connect

    Brennan, R.; Quade, J.

    1995-12-01

    Fossil mollusk shells from late Quaternary deposits in Southern Nevada were radiocarbon dated to determine the age of paleogroundwater discharge events and to establish minimum {sup 14}C ages of paleogroundwater. Shells of the terrestrial taxa Vallonia sp. and Succineidae returned {sup 14}C dates consistent with those on organic material in the same stratigraphic position. The aquatic taxa Gyraulus parvus and Gyraulus circumstratus returned the oldest dates within each unit samples. These results show that (1) fossil Vallonia and Succineidae are useful in dating deposits in which no other radiocarbon-datable material is available, and (2) Gyraulus sp. select micro habitats with the most {sup 14}C deficient water, providing minimum ages of groundwater in the area during the last glacial period.

  18. Map showing locations of samples dated by radiocarbon methods in the San Francisco Bay region

    USGS Publications Warehouse

    Wright, Robert H.

    1971-01-01

    The potential value of a radiocarbon date is diminished, however, if adequate site data are not taken with the sample and do not accompany the date in publication.  At a minimum, published dates should include an accurate location for the dated sample, type of material dated and method of dating, nature of the site, depth below surface (or other accurately defined datum) of date sample, stratigraphy of material overlying date sample, and the significance of the data in the study.

  19. Spatial analysis on China's regional air pollutants and CO2 emissions: emission pattern and regional disparity

    NASA Astrophysics Data System (ADS)

    Dong, Liang; Liang, Hanwei

    2014-08-01

    China has suffered from serious air pollution and CO2 emission. Challenges of emission reduction policy not only come from technology advancement, but also generate from the fact that, China has pronounced disparity between regions, in geographical and socioeconomic. How to deal with regional disparity is important to achieve the reduction target effectively and efficiently. This research conducts a spatial analysis on the emission patterns of three air pollutants named SO2, NOx and PM2.5, and CO2, in China's 30 provinces, applied with spatial auto-correlation and multi regression modeling. We further analyze the regional disparity and inequity issues with the approach of Lorenz curve and Gini coefficient. Results highlight that: there is evident cluster effect for the regional air pollutants and CO2 emissions. While emission amount increases from western regions to eastern regions, the emission per GDP is in inverse trend. The Lorenz curve shows an even larger unequal distribution of GDP/emissions than GDP/capita in 30 regions. Certain middle and western regions suffers from a higher emission with lower GDP, which reveal the critical issue of emission leakage. Future policy making to address such regional disparity is critical so as to promote the emission control policy under the “equity and efficiency” principle.

  20. Radiocarbon Dating.

    PubMed

    Van Strydonck, Mark

    2016-04-01

    Although most historians and art historians consider the radiocarbon dating technique not to be very precise by their criteria, the method has gained much importance over the last decades. Radiocarbon dating is increasingly used in the field of textile research and old polychrome statues, but also objects made of ivory, stucco, paper, and parchment are dated with the technique. Especially after the introduction of the AMS technique, a boom of this type of research has been noticed.

  1. Explaining regional disparities in traffic mortality by decomposing conditional probabilities

    PubMed Central

    Goldstein, Gregory P.; Clark, David E.; Travis, Lori L.; Haskins, Amy E.

    2012-01-01

    Background In the United States, the mortality rate from traffic injury is higher in rural and in southern regions, for reasons that are not well understood. Methods For 1754 (56%) of the 3142 US counties, we obtained data allowing for separation of the deaths/population (D/P) rate into deaths/injury (D/I), injuries/crash (I/C), crashes/exposure (C/E), and exposure/population (E/P), with exposure measured as vehicle miles traveled. A “decomposition method” proposed by Li and Baker was extended to study how the contributions of these components were affected by three measures of rural location, as well as southern location. Results The method of Li and Baker extended without difficulty to include non-binary effects and multiple exposures. D/I was by far the most important determinant in the county-to-county variation in D/P, and accounted for the greatest portion of the rural/urban disparity. After controlling for the rural effect, I/C accounted for most of the southern/northern disparity. Conclusions The increased mortality rate from traffic injury in rural areas can be attributed to the increased probability of death given that a person has been injured, possibly due to challenges faced by emergency medical response systems. In southern areas, there is an increased probability of injury given that a person has crashed, possibly due to differences in vehicle, road, or driving conditions. PMID:21212443

  2. First data on the radiocarbon age of the Atelian deposits in the North Caspian Region

    NASA Astrophysics Data System (ADS)

    Bezrodnykh, Yu. P.; Romanyuk, B. F.; Sorokin, V. M.; Yanina, T. A.

    2017-03-01

    This paper reports data on the Atelian horizon identified in the Caspian Sea bottom. Seismoacoustic profiling has made it possible to determine its area, position, and setting in the Upper Quaternary sequence and the relation to the host deposits. According to the drillhole core data, the Atelian horizon is composed of continental clay loam and sandy loam containing peatlike organic remains. They are depleted in biogenic residues containing rare freshwater mollusk species. The Atelian deposits were accumulated in lake reservoirs filling the depressions developed in the strata of the Upper Khazarian horizon. The radiocarbon age determined for the first time by humic acids has been used to estimate the Atelian deposition time in the range of 40 000-45 000 calibrated years BP.

  3. Regional Disparities in the Allocation of China's Higher Education Resources from the Perspective of Equity

    ERIC Educational Resources Information Center

    Wei, Bao

    2012-01-01

    This article attempts to analyze the changing circumstances of the regional disparities in the allocation of China's higher educational resources before and after the increase in college enrollments, as well as the mechanisms that have affected these circumstances. The conclusions are that regional disparities in the allocation of China's funding…

  4. Regional Disparities in the Allocation of China's Higher Education Resources from the Perspective of Equity

    ERIC Educational Resources Information Center

    Wei, Bao

    2012-01-01

    This article attempts to analyze the changing circumstances of the regional disparities in the allocation of China's higher educational resources before and after the increase in college enrollments, as well as the mechanisms that have affected these circumstances. The conclusions are that regional disparities in the allocation of China's funding…

  5. Assessment of Appalachian region pediatric hearing healthcare disparities and delays.

    PubMed

    Bush, Matthew L; Osetinsky, Mariel; Shinn, Jennifer B; Gal, Thomas J; Ding, Xiuhua; Fardo, David W; Schoenberg, Nancy

    2014-07-01

    The purpose of this study was to examine the timing of diagnostic and therapeutic services in cochlear implant recipients from a rural Appalachian region with healthcare disparity. Retrospective analysis. Cochlear implant recipients from a tertiary referral center born with severe congenital sensorineural hearing loss were examined. Rural status and Appalachian status of their county of origin were recorded. A log-rank test was used to examine differences in the distributions of time to definitive diagnosis of hearing loss, initial amplification fitting, and cochlear implantation in these children. Correlation analysis of the rural status of each county and the timing of services was assessed. A total of 53 children born with congenital hearing loss were included in the study (36 from rural counties and 17 from urban/suburban counties). The distribution of weeks after birth to diagnosis (P=.006), amplification (P=.030), and cochlear implantation (P=.002) was delayed in rural children compared with urban children. An analysis factoring in the effect of implementation of mandatory infant hearing screening in 2000 demonstrated a similar delay in rural children for weeks to diagnosis (P=.028), amplification (P=.087), and cochlear implantation (P<.0001). Children with severe hearing loss in very rural areas, such as Appalachia, may have significant delays in diagnostic and rehabilitative services. Further investigation is warranted to assess causative factors in delays of cochlear implantation and to develop interventions to promote timely diagnosis and care. 3b. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

  6. Long-term regional precipitation disparity in northwestern China and its driving forces

    NASA Astrophysics Data System (ADS)

    Lee, H. F.; Pei, Q.; Zhang, D. D.; Choi, K. P. K.

    2014-08-01

    Subject to the unique physical setting of northwestern China (NW China), precipitation in the region is characterized by salient regional differences. Yet, the long-term regional precipitation disparity in NW China still remains insufficiently-explored. In the present study, we base on historical documentation to reconstruct the precipitation indices of two macro regions in NW China between AD580-1979 to address the following issues: (1) determine the multi-decadal to centennial regional precipitation disparity in NW China, a topic which has not been systematically examined in previous paleo-climate/paleo-environment studies; and (2) find the major driving forces behind it. Wavelet analysis, which is ideal for analyzing non-stationary systems, is applied. Our results show that there is significant regional discrepancy of precipitation change in NW China over extended period. Although there is significant association between the regional precipitation disparity in NW China and various modes of atmospheric circulation, the association is characterized by a regime shift during the transition from the Medieval Warm Period to the Little Ice Age. Most importantly, the low-frequency cycle of the El Niño-Southern Oscillation is found to be the most prominent pacemaker of regional precipitation disparity in NW China at the multi-decadal to centennial timescales. Our findings help to demonstrate which atmospheric circulation is primarily responsible for the long-term regional precipitation disparity in NW China, which may have important implications for water resource management in NW China in the near future.

  7. Regional disparities in the quality of stroke care.

    PubMed

    Seabury, Seth; Bognar, Katalin; Xu, Yaping; Huber, Caroline; Commerford, S Renee; Tayama, Darren

    2017-09-01

    There is widespread geographic variation in healthcare quality, but we often lack clear strategies for improving quality in underserved areas. This study characterized geographic disparities in stroke care quality to assess whether improved access to neurological services has the potential to bridge the care quality gap, particularly in terms of alteplase (rt-PA) administration. This was a retrospective study using quality performance data from the 2015 Hospital Compare database linked to information on certification status from the Joint Commission and information on local access to neurological services from the Area Health Resources File. We used these data to compare stroke care quality according to geographic area, certification, and neurologist access. Non-metropolitan hospitals performed worse than metropolitan hospitals on all assessed stroke care quality measures. The most prevalent disparity occurred in the use of rt-PA for eligible patients (52.2% versus 82.7%, respectively). Certified stroke centers in every geographic designation provided higher quality of care, whereas large variation was observed among non-certified hospitals. Regression analyses suggested that improvements in hospital certification or access to neurologists were associated with absolute improvements of 44.9% and 21.3%, respectively, in the percentage of patients receiving rt-PA. The large quality gap in stroke care between metropolitan and non-metropolitan areas could be at least partly addressed through improved procedural efforts by stroke center certification increasing the supply of neurological services, (i.e. through training and hiring new neurologists) or by adopting decision support systems such as telemedicine. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Regional Disparities in Online Map User Access Volume and Determining Factors

    NASA Astrophysics Data System (ADS)

    Li, R.; Yang, N.; Li, R.; Huang, W.; Wu, H.

    2017-09-01

    The regional disparities of online map user access volume (use `user access volume' in this paper to indicate briefly) is a topic of growing interest with the increment of popularity in public users, which helps to target the construction of geographic information services for different areas. At first place we statistically analysed the online map user access logs and quantified these regional access disparities on different scales. The results show that the volume of user access is decreasing from east to the west in China as a whole, while East China produces the most access volume; these cities are also the crucial economic and transport centres. Then Principal Component Regression (PCR) is applied to explore the regional disparities of user access volume. A determining model for Online Map access volume is proposed afterwards, which indicates that area scale is the primary determining factor for regional disparities, followed by public transport development level and public service development level. Other factors like user quality index and financial index have very limited influence on the user access volume. According to the study of regional disparities in user access volume, map providers can reasonably dispatch and allocate the data resources and service resources in each area and improve the operational efficiency of the Online Map server cluster.

  9. Radiocarbon Dating the Anthropocene

    NASA Astrophysics Data System (ADS)

    Chaput, M. A.; Gajewski, K. J.

    2015-12-01

    The Anthropocene has no agreed start date since current suggestions for its beginning range from Pre-Industrial times to the Industrial Revolution, and from the mid-twentieth century to the future. To set the boundary of the Anthropocene in geological time, we must first understand when, how and to what extent humans began altering the Earth system. One aspect of this involves reconstructing the effects of prehistoric human activity on the physical landscape. However, for global reconstructions of land use and land cover change to be more accurately interpreted in the context of human interaction with the landscape, large-scale spatio-temporal demographic changes in prehistoric populations must be known. Estimates of the relative number of prehistoric humans in different regions of the world and at different moments in time are needed. To this end, we analyze a dataset of radiocarbon dates from the Canadian Archaeological Radiocarbon Database (CARD), the Palaeolithic Database of Europe and the AustArch Database of Australia, as well as published dates from South America. This is the first time such a large quantity of dates (approximately 60,000) has been mapped and studied at a global scale. Initial results from the analysis of temporal frequency distributions of calibrated radiocarbon dates, assumed to be proportional to population density, will be discussed. The utility of radiocarbon dates in studies of the Anthropocene will be evaluated and potential links between population density and changes in atmospheric greenhouse gas concentrations, climate, migration patterning and fire frequency coincidence will be considered.

  10. Disparities in child health in the Arab region during the 1990s

    PubMed Central

    Khawaja, Marwan; Dawns, Jesse; Meyerson-Knox, Sonya; Yamout, Rouham

    2008-01-01

    Background While Arab countries showed an impressive decline in child mortality rates during the past few decades, gaps in mortality by gender and socioeconomic status persisted. However, large socioeconomic disparities in child health were evident in almost every country in the region. Methods Using available tabulations and reliable micro data from national household surveys, data for 18 Arab countries were available for analysis. In addition to infant and child mortality, child health was measured by nutritional status, vaccination, and Acute Respiratory Infection (ARI). Within-country disparities in child health by gender, residence (urban/rural) and maternal educational level were described. Child health was also analyzed by macro measures of development, including per capita GDP (PPP), female literacy rates, urban population and doctors per 100,000 people. Results Gender disparities in child health using the above indicators were less evident, with most showing clear female advantage. With the exception of infant and child survival, gender disparities demonstrated a female advantage, as well as a large urban advantage and an overall advantage for mothers with secondary education. Surprisingly, the countries' rankings with respect to disparities were not associated with various macro measures of development. Conclusion The tenacity of pervasive intra-country socioeconomic disparities in child health calls for attention by policy makers and health practitioners. PMID:19021903

  11. Assessing Needs and Assets for Building a Regional Network Infrastructure to Reduce Cancer Related Health Disparities

    PubMed Central

    Wells, Kristen J.; Lima, Diana S.; Meade, Cathy D.; Muñoz-Antonia, Teresita; Scarinci, Isabel; McGuire, Allison; Gwede, Clement K.; Pledger, W. Jack; Partridge, Edward; Lipscomb, Joseph; Matthews, Roland; Matta, Jaime; Flores, Idhaliz; Weiner, Roy; Turner, Timothy; Miele, Lucio; Wiese, Thomas E.; Fouad, Mona; Moreno, Carlos S.; Lacey, Michelle; Christie, Debra W.; Price-Haywood, Eboni G.; Quinn, Gwendolyn P.; Coppola, Domenico; Sodeke, Stephen O.; Green, B. Lee; Lichtveld, Maureen Y.

    2015-01-01

    Significant cancer health disparities exist in the United States and Puerto Rico. While numerous initiatives have been implemented to reduce cancer disparities, regional coordination of these efforts between institutions is often limited. To address cancer health disparities nationwide, a series of regional transdisciplinary networks through the Geographic Management Program (GMaP) and the Minority Biospecimen/Biobanking Geographic Management Program (BMaP) were established in six regions across the country. This paper describes the development of the Region 3 GMaP/BMaP network composed of over 100 investigators from nine institutions in five Southeastern states and Puerto Rico to develop a state-of-the-art network for cancer health disparities research and training. We describe a series of partnership activities that led to the formation of the infrastructure for this network, recount the participatory processes utilized to develop and implement a needs and assets assessment and implementation plan, and describe our approach to data collection. Completion, by all nine institutions, of the needs and assets assessment resulted in several beneficial outcomes for Region 3 GMaP/BMaP. This network entails ongoing commitment from the institutions and institutional leaders, continuous participatory and engagement activities, and effective coordination and communication centered on team science goals. PMID:24486917

  12. Assessing needs and assets for building a regional network infrastructure to reduce cancer related health disparities.

    PubMed

    Wells, Kristen J; Lima, Diana S; Meade, Cathy D; Muñoz-Antonia, Teresita; Scarinci, Isabel; McGuire, Allison; Gwede, Clement K; Pledger, W Jack; Partridge, Edward; Lipscomb, Joseph; Matthews, Roland; Matta, Jaime; Flores, Idhaliz; Weiner, Roy; Turner, Timothy; Miele, Lucio; Wiese, Thomas E; Fouad, Mona; Moreno, Carlos S; Lacey, Michelle; Christie, Debra W; Price-Haywood, Eboni G; Quinn, Gwendolyn P; Coppola, Domenico; Sodeke, Stephen O; Green, B Lee; Lichtveld, Maureen Y

    2014-06-01

    Significant cancer health disparities exist in the United States and Puerto Rico. While numerous initiatives have been implemented to reduce cancer disparities, regional coordination of these efforts between institutions is often limited. To address cancer health disparities nation-wide, a series of regional transdisciplinary networks through the Geographic Management Program (GMaP) and the Minority Biospecimen/Biobanking Geographic Management Program (BMaP) were established in six regions across the country. This paper describes the development of the Region 3 GMaP/BMaP network composed of over 100 investigators from nine institutions in five Southeastern states and Puerto Rico to develop a state-of-the-art network for cancer health disparities research and training. We describe a series of partnership activities that led to the formation of the infrastructure for this network, recount the participatory processes utilized to develop and implement a needs and assets assessment and implementation plan, and describe our approach to data collection. Completion, by all nine institutions, of the needs and assets assessment resulted in several beneficial outcomes for Region 3 GMaP/BMaP. This network entails ongoing commitment from the institutions and institutional leaders, continuous participatory and engagement activities, and effective coordination and communication centered on team science goals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Hierarchical Regional Disparities and Potential Sector Identification Using Modified Agglomerative Clustering

    NASA Astrophysics Data System (ADS)

    Munandar, T. A.; Azhari; Mushdholifah, A.; Arsyad, L.

    2017-03-01

    Disparities in regional development methods are commonly identified using the Klassen Typology and Location Quotient. Both methods typically use the data on the gross regional domestic product (GRDP) sectors of a particular region. The Klassen approach can identify regional disparities by classifying the GRDP sector data into four classes, namely Quadrants I, II, III, and IV. Each quadrant indicates a certain level of regional disparities based on the GRDP sector value of the said region. Meanwhile, the Location Quotient (LQ) is usually used to identify potential sectors in a particular region so as to determine which sectors are potential and which ones are not potential. LQ classifies each sector into three classes namely, the basic sector, the non-basic sector with a competitive advantage, and the non-basic sector which can only meet its own necessities. Both Klassen Typology and LQ are unable to visualize the relationship of achievements in the development clearly of each region and sector. This research aimed to develop a new approach to the identification of disparities in regional development in the form of hierarchical clustering. The method of Hierarchical Agglomerative Clustering (HAC) was employed as the basis of the hierarchical clustering model for identifying disparities in regional development. Modifications were made to HAC using the Klassen Typology and LQ. Then, HAC which had been modified using the Klassen Typology was called MHACK while HAC which had been modified using LQ was called MACLoQ. Both algorithms can be used to identify regional disparities (MHACK) and potential sectors (MACLoQ), respectively, in the form of hierarchical clusters. Based on the MHACK in 31 regencies in Central Java Province, it is identified that 3 regencies (Demak, Jepara, and Magelang City) fall into the category of developed and rapidly-growing regions, while the other 28 regencies fall into the category of developed but depressed regions. Results of the MACLo

  14. Diabetes care: provider disparities in the US Appalachian region.

    PubMed

    Denham, Sharon A; Wood, Lawrence E; Remsberg, Karen

    2010-01-01

    Diabetes is a devastating and growing problem in the USA and throughout the world. Parts of Appalachia, especially the most rural and economically 'distressed' areas of the region, have disproportionately high levels of diabetes incidence and have had long-standing problems in healthcare access. Little is known about the status of public health infrastructures and expertise available to address the diabetes epidemic, whether in Appalachia or elsewhere. This research examines the availability of professional diabetes care in Appalachia, including the economically distressed areas of the region. A 2006 cross-sectional survey of healthcare providers in the Appalachian Region identified diabetes service needs and availability in Appalachian healthcare facilities. Survey data and socioeconomic data were combined as a means to assess intra-regional variation in service availability. Participants perceived that diabetes prevalence was growing in Appalachia and that they were seeing increasing numbers of persons with diabetes. Healthcare facilities in the region rarely employed specialized health professional providers and the expertise concerning diabetes in some clinicians may be limited. The current and growing diabetes problem in Appalachia underscores the need for appropriate diabetes services and health professionals acquainted with current standards in diabetes care. Such problems in Appalachia have long been identified and linked with insufficient healthcare resources. The identification of ways to assure that local clinicians have current knowledge of diabetes standards of care is warranted.

  15. Regional Disparities in Primary School Participation in Developing Countries

    ERIC Educational Resources Information Center

    Sherman, Joel D.

    2008-01-01

    Education for All has focused international attention on the goals of universal primary education and improved education quality. However, national indicators related to these goals often mask significant differences among demographic and social groups, as well as among geographical regions within countries. This paper, based on a study…

  16. Environmental health disparities in the Central Appalachian region of the United States.

    PubMed

    Krometis, Leigh-Anne; Gohlke, Julia; Kolivras, Korine; Satterwhite, Emily; Marmagas, Susan West; Marr, Linsey C

    2017-07-06

    Health disparities that cannot be fully explained by socio-behavioral factors persist in the Central Appalachian region of the United States. A review of available studies of environmental impacts on Appalachian health and analysis of recent public data indicates that while disparities exist, most studies of local environmental quality focus on the preservation of nonhuman biodiversity rather than on effects on human health. The limited public health studies available focus primarily on the impacts of coal mining and do not measure personal exposure, constraining the ability to identify causal relationships between environmental conditions and public health. Future efforts must engage community members in examining all potential sources of environmental health disparities to identify effective potential interventions.

  17. Rising prevalence of back pain in Austria: considering regional disparities.

    PubMed

    Großschädl, Franziska; Stolz, Erwin; Mayerl, Hannes; Rásky, Éva; Freidl, Wolfgang; Stronegger, Willibald J

    2016-01-01

    Back pain is the most common form of musculoskeletal conditions and leads to high health care costs. Information about geographic variations in highly prevalent diseases/disorders represents important implications for public health planning to face structural challenges. The present study aims to investigate regional trends in the prevalence of back pain and the role of obesity and social inequalities among Austrian adults. A secondary data analysis based on five nationally representative cross-sectional surveys (1973-2007) was carried out (N = 178,818). Back pain was measured as self-reported presence. Obesity (BMI ≥ 30 kg/m²) was adjusted for self-report bias. For the regional analyses, Austria was divided into Western, Central and Eastern Austria. A relative index of inequality (RII) was computed to quantify the extent of social inequality. A continuous rise in back pain prevalence was observed in the three regions and among all investigated subgroups. In 2007 the age-standardised prevalence was similar in Central (36.9 %), Western (35.2 %) and Eastern Austria (34.3 %). The absolute change in back pain prevalence was highest among obese subjects in Central Austria (women: + 29.8 %, men: + 32.5 %). RIIs were unstable during the study period and in 2007 highest in Eastern Austria. Variation and trends in back pain are not attributable to geographic variation in Austria: an assumed East-West gradient in Austria has not been confirmed. Nevertheless our study confirms that back pain dramatically increased in all Austrian regions and investigated subgroups. This worrying trend should be further monitored and public health interventions should be implemented increasingly, especially among obese women and men.

  18. Recent trends in racial and regional disparities in cervical cancer incidence and mortality in United States

    PubMed Central

    Kim, Sangmi

    2017-01-01

    Background Although black women experienced greater cervical cancer incidence and mortality rate reduction in recent years, they continue to have higher incidence rates than whites. Great variations also exist among geographic regions of the US, with the South having both the highest incidence and mortality rates compared to other regions. The present study explores the question of whether living in the South is associated with greater racial disparity in cervical cancer incidence and mortality by examining race- and region-specific rates and the trend between 2000 and 2012. Methods The Surveillance, Epidemiology, and End Results (SEER) 18 Program data was used. Cervical cancer incidence and mortality rates, annual percent changes, and disparity ratios were calculated using SEER*Stat software and Joinpoint regression for four groups: US14-Non-Hispanic White (NHW), US14-Non-Hispanic Black (NHB), South-NHW, and South-NHB, where South included 4 registries from Georgia and Louisiana and US14 were 14 US registries except the four South registries. Results The average age-adjusted cervical cancer incidence rate was the highest among South-NHBs (11.1) and mortality rate was the highest among US14-NHBs (5.4). In 2012, the degree of racial disparities between South-NHBs and South-NHWs was greater in terms of mortality rates (NHB:NHW = 1.80:1.35) than incidence rates (NHB:NHW = 1.45:1.15). While mortality disparity ratios decreased from 2000–2012 for US14-NHB (APC: -1.9(-2.3,-1.4), mortality disparity ratios for South-NHWs (although lower than NHBs) increased compared to US14-NHW. Incidence rates for NHBs continued to increase with increasing age, whereas rates for NHWs decreased after age 40. Mortality rates for NHBs dramatically increased at age 65 compared to a relatively stable trend for NHWs. The increasing racial disparity with increasing age in terms of cervical cancer incidence rates became more pronounced when corrected for hysterectomy prevalence. Conclusions

  19. Disparities in Physical Activity Resource Availability in Six US Regions

    PubMed Central

    Jones, Sydney A.; Moore, Latetia V.; Moore, Kari; Zagorski, Melissa; Brines, Shannon J.; Diez Roux, Ana V.; Evenson, Kelly R.

    2015-01-01

    We conducted an ecologic study to determine physical activity resource availability overall and by sociodemographic groups in parts of six states (CA, IL, MD, MN, NC, NY). Data on parks and recreational facilities were collected from 3 sources in 2009–2012. Three measures characterized park and recreational facility availability at the census tract level: presence of ≥1 resource, number of resources, and resource kernel density. Associations between resource availability and census tract characteristics (predominant racial/ethnic group, median income, and proportion of children and older adults) were estimated using linear, binomial, and zero-inflated negative binomial regression in 2014. Pooled and stratified analyses were conducted. The study included 7,139 census tracts, comprising 9.5% of the 2010 US population. Overall the availability of parks and recreational facilities was lower in predominantly minority relative to non-Hispanic white census tracts. Low-income census tracts and those with a higher proportion of children had an equal or greater availability of park resources but fewer recreational facilities. Stratification revealed substantial variation in resource availability by state. The availability of physical activity resources varied by sociodemographic characteristics and across regions. Improved knowledge of resource distribution can inform strategies to provide equitable access to parks and recreational facilities. PMID:26067479

  20. [Disparity on the grade of exposure to ecological risks in the European region of WHO].

    PubMed

    Braubach, M; Héroux, M E; Korol, N; Kosbaeva, A; Paunovic, E; Zastenskaia, I

    2015-01-01

    Disparity in relation of ecological conditions and health concerns to the general differences in environmental conditions and in large extent is stipulated by socio-economic and demographic differences in the impact of its hazards. In addition to differences in the impact the inequality in relation of ecological conditions and health can also be caused by social or demographic differences in exposure to certain risks. This article offers an assessment of the evidence and data on differences in the impact of the environment in the European Region of the World Health Organization (WHO) received during the recent work of the European Regional Office of WHO. The obtained results testify that socio-demographic disparity in the impact of the environment exists in all countries. Such inequality can be seen in respect of a variety offactors, such as age, gender income level, or on the contrary, poverty, education and employment, household type, location of the home.

  1. Regional disparities in the distribution of healthcare workers: evidence from Iran, Chaharmahal and Bakhtiari province.

    PubMed

    Ezati Asar, Mohamad; Varehzardi, Ramin; Rajabi Vasokolaei, Ghasem; Haghi, Mehdi; Fazelipor, Morteza

    2015-02-09

    A health care service is a prerequisite for sustainable development. This requires access to balanced health workers in different geographic areas. The first step is to identify inequality in access to health workers in different areas. This study is a descriptive study was carried out on the cities in Chaharmahal and Bakhtiari province. TOPSIS technique was used to rank the cities in terms of regional disparities in the distribution of health workers. The findings revealed that distinct disparities in the distribution of healthcare workers across Chaharmahal and Bakhtiari province. Shahrekord and Ardal cities were classified as 1st and 7th respectively. Policy makers should consider priority (regional planning, budget and resources allocation) according to the distribution of healthcare workers.

  2. Biological factors that may contribute to regional and racial disparities in HIV prevalence.

    PubMed

    Kaul, Rupert; Cohen, Craig R; Chege, Duncan; Yi, Tae J; Tharao, Wangari; McKinnon, Lyle R; Remis, Robert; Anzala, Omu; Kimani, Joshua

    2011-03-01

    Despite tremendous regional and subregional disparities in HIV prevalence around the world, epidemiology consistently demonstrates that black communities have been disproportionately affected by the pandemic. There are many reasons for this, and a narrow focus on socio-behavioural causes may be seen as laying blame on affected communities or individuals. HIV sexual transmission is very inefficient, and a number of biological factors are critical in determining whether an unprotected sexual exposure to HIV results in productive infection. This review will focus on ways in which biology, rather than behaviour, may contribute to regional and racial differences in HIV epidemic spread. Specific areas of focus are viral factors, host genetics, and the impact of co-infections and host immunology. Considering biological causes for these racial disparities may help to destigmatize the issue and lead to new and more effective strategies for prevention. © 2011 John Wiley & Sons A/S.

  3. Regional disparities in interferon therapy for chronic hepatitis C in Japan: a nationwide retrospective cohort study.

    PubMed

    Masaki, Naohiko; Yamagiwa, Yoko; Shimbo, Takuro; Murata, Kazumoto; Korenaga, Masaaki; Kanto, Tatsuya; Mizokami, Masashi

    2015-06-19

    Many patients with chronic hepatitis C have been treated with interferon (IFN) therapy in Japan, especially after the introduction of subsidies for medical expenses in 2008. However, its performance and outcome have never been evaluated. Therefore, a nationwide, mail-based, retrospective cohort study was conducted. Regional disparities in the demographic features, treatment performance, and virological response were evaluated using an intent-to-treat design. The participating prefectures were classified into nine regions from north to south (Hokkaido/Tohoku, Kanto, Shin-etsu, Hokuriku, Tokai, Kinki, Chugoku, Shikoku, and Kyushu). Multivariate logistic regression analysis was performed to select predictive factors for treatment performance and outcome. From December 2009 to May 2013, 16,854 patients with chronic hepatitis C were registered from 37 prefectures in Japan (median age: 60 years; 50.4% male; 74.8% IFN-naïve; HCV genotype [1 or 2]/viral load [high (≥5 log IU/mL) or low (<5 log IU/mL)]: 1/high = 58.2%, 1/low = 5.2%, 2/high = 27.3%, 2/low = 7.5%; 83.4% treated with peginterferon-α and ribavirin). Mean age, proportion of elderly patients (≥65 years), male sex, IFN-experienced, and HCV genotype were significantly different among the nine regions (all P < 0.001). Regional disparities were independently selected as one of the predictive factors for treatment performance and outcome in patients treated with peginterferon-α and ribavirin, which revealed two regions that required further investigation. Regional disparities still exist in IFN therapy, and are strongly associated with treatment performance and outcome. Since the accessibility to medical resources for individual patients seemed to be different among the nine regions, public health actions should be focused on how to construct and properly manage consultation networks between base hospitals and local clinics, especially in those regions with low population density.

  4. Stroke mortality disparities in the population of the Appalachian Mountain region.

    PubMed

    Sergeev, Alexander V

    2013-01-01

    Racial and rural-urban differences in stroke were previously reported in demographically and socioeconomically heterogeneous populations. However, it is not clear whether they exist in more homogeneous populations. Compared to the rest of the United States, the Appalachian region is highly rural and more homogeneous, with a predominantly White and socioeconomically disadvantaged population. The goal of our study was to investigate whether racial disparities in stroke mortality exist among the Appalachian population. Patterns of stroke mortality for a seven-year period (2000-2006) were investigated in the Appalachian adult population of > or = 25 years. Data on stroke deaths were obtained from the Centers for Disease Control and Prevention, National Center for Health Statistics. Multivariable Poisson regression models were used to estimate adjusted relative risks (RR), adjusting for confounding factors. Stroke death rates. Stroke mortality in Appalachia was 20.5% higher than outside Appalachia (96.67 and 80.25 per 100,000 person-years, P < .001). Stroke mortality was statistically significantly higher in African Americans than in other racial groups: Caucasians (adjusted RR = 1.428, P < .001), Asians (adjusted RR = 2.821, P < .001), and Native American Indians (adjusted RR = 3.571, P < 0.001). Rural-urban stroke mortality disparities were statistically significant outside Appalachia but not within Appalachia. Racial disparities in stroke mortality exist in the Appalachian region. Further studies are warranted to investigate the rationale for possible health policy interventions and socioeconomic measures.

  5. Multilevel analysis of the role of human factors in regional disparities in crash outcomes.

    PubMed

    Adanu, Emmanuel Kofi; Smith, Randy; Powell, Lars; Jones, Steven

    2017-10-06

    A growing body of research has examined the disparities in road traffic safety among population groups and geographic regions. These studies reveal disparities in crash outcomes between people and regions with different socioeconomic characteristics. A critical aspect of the road traffic crash epidemic that has received limited attention is the influence of local characteristics on human elements that increase the risk of getting into a crash. This paper applies multilevel logistic regression modeling techniques to investigate the influence of driver residential factors on driver behaviors in an attempt to explain the area-based differences in the severity of road crashes across the State of Alabama. Specifically, the paper reports the effects of characteristics attributable to drivers and the geographic regions they reside on the likelihood of a crash resulting in serious injuries. Model estimation revealed that driver residence (postal code or region) accounted for about 7.3% of the variability in the probability of a driver getting into a serious injury crash, regardless of driver characteristics. The results also reveal disparities in serious injury crash rate as well as significant proportions of serious injury crashes involving no seatbelt usage, driving under influence (DUI), unemployed drivers, young drivers, distracted driving, and African American drivers among some regions. The average credit scores, average commute times, and populations of driver postal codes are shown to be significant predictors for risk of severe injury crashes. This approach to traffic crash analysis presented can serve as the foundation for evidence-based policies and also guide the implementation of targeted countermeasures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. A revisit to prevailing care and challenges of managing diabetes in India: Focus on regional disparities

    PubMed Central

    Baruah, Manash P.; Pathak, Ankit; Kalra, Sanjay; Das, Ashok K.; Zargar, Abdul H.; Bajaj, Sarita; Unnikrishnan, Ambika G.; Sahay, Rakesh K.

    2014-01-01

    An unprecedented rise in diabetes mellitus (DM) prevalence in India is the outcome of lifestyle changes in the background of genetic predisposition. Moreover, there are substantial regional variations in diabetes prevalence and management. The highest prevalence of DM was observed in southern region (Ernakulum, Kerala) and lowest prevalence was observed in North Eastern region (Manipur). Similarly large variations have been evident in overall awareness and diabetes care across the geographies within India. The regional challenges are largely affected by poor disease awareness, socioeconomic disparity and underutilization of the public health-care services. Though government has taken initiatives to address this issue, overall situation demands a collaborative effort from patients, health care professionals and the state. An exhaustive literature search was performed for articles and studies published on electronic databases. Present article assesses the regional disparity of diabetes epidemiology, current management practices and government policies for T2DM in India, identifies policy and research gaps, and suggests corrective measures to address the lacunae in diabetes care. PMID:24944916

  7. Disparities in the Use of Radiation Therapy in Patients With Local-Regionally Advanced Breast Cancer

    SciTech Connect

    Martinez, Steve R.; Beal, Shannon H.; Chen, Steven L.; Canter, Robert J.; Khatri, Vijay P.; Chen, Allen; Bold, Richard J.

    2010-11-01

    Background: Radiation therapy (RT) is indicated for the treatment of local-regionally advanced breast cancer (BCa). Hypothesis: We hypothesized that black and Hispanic patients with local-regionally advanced BCa would receive lower rates of RT than their white counterparts. Methods: The Surveillance Epidemiology and End Results database was used to identify white, black, Hispanic, and Asian patients with invasive BCa and {>=}10 metastatic lymph nodes diagnosed between 1988 and 2005. Univariate and multivariate logistic regression evaluated the relationship of race/ethnicity with use of RT. Multivariate models stratified for those undergoing mastectomy or lumpectomy. Results: Entry criteria were met by 12,653 patients. Approximately half of the patients did not receive RT. Most patients were white (72%); the remainder were Hispanic (10.4%), black (10.3%), and Asian (7.3%). On univariate analysis, Hispanics (odd ratio [OR] 0.89; 95% confidence interval [CI], 0.79-1.00) and blacks (OR 0.79; 95% CI, 0.70-0.89) were less likely to receive RT than whites. On multivariate analysis, blacks (OR 0.76; 95% CI, 0.67-0.86) and Hispanics (OR 0.80; 95% CI, 0.70-0.90) were less likely than whites to receive RT. Disparities persisted for blacks (OR 0.74; 95% CI, 0.64-0.85) and Hispanics (OR 0.77; 95% CI, 0.67-0.89) who received mastectomy, but not for those who received lumpectomy. Conclusions: Many patients with local-regionally advanced BCa do not receive RT. Blacks and Hispanics were less likely than whites to receive RT. This disparity was noted predominately in patients who received mastectomy. Future efforts at improving rates of RT are warranted. Efforts at eliminating racial/ethnic disparities should focus on black and Hispanic candidates for postmastectomy RT.

  8. [Regional disparity on life expectancy, active life expectancy in the elderly from Beijing].

    PubMed

    Zhang, Zhong-ying; Tang, Zhe; Feng, Ming

    2011-09-01

    To explore the regional disparity in life expectancy (LE), active life expectancy (ALE), active life expectancy/life expectancy (ALE/LE) of the elderly in Beijing and to express the impact of hypertension upon those indices. The sample was derived from a "Beijing multidimensional longitudinal study on aging", including those from urban district (Xuanwu), rural district (Daxing and Huairou) by well-established statistical sampling techniques. Baseline survey comprised 1847 people aged 60 years or over, living in the communities in Beijing in 2004. The subjects under research were investigated with questionnaires at home by well-trained interviews and the contents would include: degree of education, occupation, medical history of hypertension together with repeated blood pressure measurements. Someone being "active" was defined as the ability in performing activities of daily life (ADL). IMaCH software for multi-state life table method was used to calculate the life expectancy (LE), active life expectancy (ALE) and active life expectancy/life expectancy (ALE/LE) in different district and the hypertensive exert influence on those indices. Data from the study showed that people inhabited in the rural district had lower LE, ALE and degree of education (illiteracy account for 66.2 percentage), but with more physical activities (account for 95.5 percentage) and higher ALE/LE than urban district people. Regional disparity in Females was obvious than in males while hypertension would exert more influence on LE of the urban women, which widened the gap in LE, ALE of males and ALE of females between the urban and rural areas. Regional disparity was found existing in LE, ALE, ALE/LE of the elderly from Beijing, particularly in females. Hypertension widened the gap and decreased the quality of life on senior citizens in the rural areas. This finding underlined the influence of habitation on the quality of life which manifested the importance of prevention regarding high blood

  9. Regional and County-Level Disparities in the Post-Socialist Urban System of Romania

    NASA Astrophysics Data System (ADS)

    Török, Ibolya; Veress, Nóra-Csilla

    2016-10-01

    The evolution of the urban system in Romania in the last decades has been strongly influenced by its historical background, as well as the changing political, social and economic context. The main step in this process was marked by the year 2004 when 38 settlements received the urban status, influencing thus not only the country's urbanization level but the increased inter-regional disparities as well. The paper aims to analyze the post-urbanization process in Romania, highlighting those factors which have contributed to the deepening development differences between the country's urban areas.

  10. Trends and Disparities in Stroke Mortality by Region for American Indians and Alaska Natives

    PubMed Central

    Ayala, Carma; Valderrama, Amy L.; Veazie, Mark A.

    2014-01-01

    Objectives. We evaluated trends and disparities in stroke death rates for American Indians and Alaska Natives (AI/ANs) and White people by Indian Health Service region. Methods. We identified stroke deaths among AI/AN persons and Whites (adults aged 35 years or older) using National Vital Statistics System data for 1990 to 2009. We used linkages with Indian Health Service patient registration data to adjust for misclassification of race for AI/AN persons. Analyses excluded Hispanics and focused on Contract Health Service Delivery Area (CHSDA) counties. Results. Stroke death rates among AI/AN individuals were higher than among Whites for both men and women in CHSDA counties and were highest in the youngest age groups. Rates and AI/AN:White rate ratios varied by region, with the highest in Alaska and the lowest in the Southwest. Stroke death rates among AI/AN persons decreased in all regions beginning in 2001. Conclusions. Although stroke death rates among AI/AN populations have decreased over time, rates are still higher for AI/AN persons than for Whites. Interventions that address reducing stroke risk factors, increasing awareness of stroke symptoms, and increasing access to specialty care for stroke may be more successful at reducing disparities in stroke death rates. PMID:24754653

  11. Regional benthic δ18O stacks with radiocarbon age models show Termination I onset differences of up to 4,000 years

    NASA Astrophysics Data System (ADS)

    Stern, J.; Lisiecki, L. E.

    2013-12-01

    The assumption of globally synchronous benthic foraminiferal δ18O changes is central to the development of global stacks (averages) and many other types of paleoclimate studies. However, a few well-dated individual benthic δ18O records have suggested the possibility of regional differences in the timing of Termination I (e.g., Skinner and Shackleton, 2005; Waelbroeck et al., 2011). These previous studies often used single core locations to describe vast areas of the ocean, so it has remained unclear whether the observed diachroneities are truly regional in scale or merely local. Here, we bridge the gap between global benthic δ18O stacks and individual records by presenting eight regional benthic δ18O stacks from 252 cores with age models based on a total of 776 planktonic foraminiferal radiocarbon dates from 61 of those cores. The earliest termination onset (beginning of deglacial benthic δ18O decrease) occurs in the intermediate South Atlantic stack at 18.5 kyr BP, shortly after the initial deglacial melting of Northern Hemisphere ice sheets. The latest termination onset occurs in the deep Indian stack at 14.5 kyr BP, coeval with the Bølling-Allerød warming. We find synchronous termination onsets at 17.5 kyr BP in the intermediate North Atlantic, deep North Atlantic, and deep South Atlantic, contrary to Waelbroeck et al. (2011). The deglacial benthic δ18O decrease in the deep Pacific lagged that of the deep Atlantic by an average of 1000 yr, with a maximum lag of ~1700 yr during the middle of the termination. The intermediate Pacific termination onset at 16.5 kyr BP happens 1000 yr after the deep Pacific termination onset at 17.5 kyr BP. The stacks extend beyond Termination I to ~40 kyr BP, allowing us to clarify and update certain aspects of millennial-scale benthic δ18O chronostratigraphy surrounding Heinrich events 2-3 and the transition into the Last Glacial Maximum. Our radiocarbon-dated regional benthic δ18O stacks demonstrate some of the

  12. Regional disparities in compliance with tobacco control policy in Japan: an ecological analysis.

    PubMed

    Yorifuji, Takashi; Tanihara, Shinichi; Takao, Soshi; Kawachi, Ichiro

    2011-09-01

    The slow progress of tobacco control policy in Japan reflects the tension among the interests of the Finance Ministry (which remains the majority shareholder of Japan Tobacco, Inc), the Health Ministry, tobacco growers and consumers. We sought to examine regional disparities in compliance with national tobacco control legislation (the 2003 Health Promotion Law). Specifically, we sought to examine whether prefecture-level compliance with legislation was correlated with decreases in smoking prevalence, and decreases in lung cancer mortality rates. We also examined whether prefectural involvement in growing tobacco was associated with lower compliance with the law. From 2001 to 2007, higher prefectural compliance with tobacco control laws was associated with decreased prevalence of smoking. Decreased tobacco consumption was in turn associated with declining lung cancer mortality. Prefectures involved in growing tobacco exhibited lower levels of compliance with national tobacco control laws. The same prefectures also exhibited the worst improvement in smoking prevalence. This study in Japan suggests that tobacco control policies are being unevenly implemented across prefectures, and that measures to counteract the influence of local tobacco culture are required to reduce the disparities in regional tobacco control outcomes in that country.

  13. Integrating disparate lidar datasets for a regional storm tide inundation analysis of Hurricane Katrina

    USGS Publications Warehouse

    Stoker, J.M.; Tyler, D.J.; Turnipseed, D.P.; Van Wilson, Jr.; Oimoen, M.J.

    2009-01-01

    Hurricane Katrina was one of the largest natural disasters in U.S. history. Due to the sheer size of the affected areas, an unprecedented regional analysis at very high resolution and accuracy was needed to properly quantify and understand the effects of the hurricane and the storm tide. Many disparate sources of lidar data were acquired and processed for varying environmental reasons by pre- and post-Katrina projects. The datasets were in several formats and projections and were processed to varying phases of completion, and as a result the task of producing a seamless digital elevation dataset required a high level of coordination, research, and revision. To create a seamless digital elevation dataset, many technical issues had to be resolved before producing the desired 1/9-arc-second (3meter) grid needed as the map base for projecting the Katrina peak storm tide throughout the affected coastal region. This report presents the methodology that was developed to construct seamless digital elevation datasets from multipurpose, multi-use, and disparate lidar datasets, and describes an easily accessible Web application for viewing the maximum storm tide caused by Hurricane Katrina in southeastern Louisiana, Mississippi, and Alabama.

  14. Regional 10Be production rate calibration for the past 12 ka deduced from two radiocarbon-dated rock avalanches at 69° N, Norway

    NASA Astrophysics Data System (ADS)

    Fenton, Cassandra R.; Hermanns, Reginald; Blikra, Lars; Kubik, Peter W.; Bryant, Charlotte; Niedermann, Samuel; Meixner, Anette; Goethals, Mirjam

    2010-05-01

    Cosmogenic 10Be is an ideal nuclide to use for surface-exposure age-dating in natural-hazards and climate-change research in northern Norway, particularly because many landslides and glacial landforms in the region contain quartz-rich lithologies. Here, we present data establishing the first regional 10Be production rate calibration for northern Norway, in the Troms county region. Systematic natural-calibration of production rates of different terrestrial cosmogenic nuclides, including 10Be, was one of the main goals set by the CRONUS-EU research network, and was the driving force behind this project. Two rock avalanches in Troms County -the Grøtlandsura and Russenes - were selected as CRONUS-EU natural cosmogenic 10Be production-rate calibration sites because they (a) preserve large boulders that have been continuously exposed to cosmic irradiation since their emplacement; (b) contain boulders with abundant quartz phenocrysts and veins with low concentrations of naturally-occurring 9Be (typically < 1.5 ppb); and (c) have reliable radiocarbon ages of 11424 ± 108 yr BP and 10942 ± 77 yr BP (1-sigma; Oxcal 4.1), respectively. BP is by convention regarded as years prior to 1950, and the radiocarbon ages are thus corrected to 2006 - the sampling year - for the purposes of calculating 10Be production rates in our study. Quartz samples (n=6) from these two sites contained between 4.41x104 and 5.10x104 at 10Be/g when normalized to the ETH's S555 standard and scaled with Lal (1991)/Stone (2000) in CosmoCalc (Vermeesch, 2007). Determination of these 10Be concentrations accounts for isostatic rebound and shielding from snow and moss cover. Using the 10Be half-lives of (1) 1.36 Myr (Nishiizumi et al., 2007), (2) 1.387 Myr (Chmeleff et al., 2009; Korschinek et al., 2009), and (3) 1.51 Myr (Hofmann et al., 1987), we calculate preliminary weighted mean total 10Be production rates of (1) 4.07±0.31, (2) 4.16±0.32, and (3) 4.52±0.34 at/g/yr (2-sigma), respectively. These are

  15. Disparities in recommended preventive care usage among persons living with diabetes in the Appalachian region.

    PubMed

    Sohn, Min-Woong; Kang, Hyojung; Park, Joseph S; Yates, Paul; McCall, Anthony; Stukenborg, George; Anderson, Roger; Balkrishnan, Rajesh; Lobo, Jennifer M

    2016-01-01

    To examine disparities in the receipt of preventive care recommended by the American Diabetes Association (ADA) between Appalachian and non-Appalachian counties and within Appalachian counties. Behavioral Risk Factor Surveillance System (BRFSS) data for 2008-2010 were used to identify individuals with diabetes and their preventive care usage. Each Appalachian respondent county of residence was categorised into one of the five economic levels: distressed, at-risk, transitional, competitive and attainment counties. Competitive and attainment counties were combined and designated as competitive counties. We used logistic regressions to compare receipt of ADA preventive care recommendations by county economic level, adjusting for respondent demographic, socioeconomic, health and access-to-care factors. Compared to the most affluent (competitive) counties, less affluent (distressed and at-risk) counties demonstrated equivalent or higher rates of self-care practices such as daily blood glucose monitoring and daily foot checks. But they showed 40-50% lower uptake of annual foot and eye examinations and 30% lower uptake of diabetes education and pneumococcal vaccinations compared to competitive counties. After adjusting for demographic factors, significant disparities still existed in the uptake of annual foot examinations, annual eye examinations, 2 or more A1c tests per year and pneumococcal vaccinations in distressed and at-risk counties compared to competitive counties. Appalachian counties as a whole were similar to non-Appalachian counties in the uptake of all recommendations with the absolute differences of ≤3%. Our results show that there are significant disparities in the uptake of many recommended preventive services between less and more affluent counties in the Appalachian region.

  16. Disparities in recommended preventive care usage among persons living with diabetes in the Appalachian region

    PubMed Central

    Sohn, Min-Woong; Kang, Hyojung; Park, Joseph S; Yates, Paul; McCall, Anthony; Stukenborg, George; Anderson, Roger; Balkrishnan, Rajesh; Lobo, Jennifer M

    2016-01-01

    Objective To examine disparities in the receipt of preventive care recommended by the American Diabetes Association (ADA) between Appalachian and non-Appalachian counties and within Appalachian counties. Research design and methods Behavioral Risk Factor Surveillance System (BRFSS) data for 2008–2010 were used to identify individuals with diabetes and their preventive care usage. Each Appalachian respondent county of residence was categorised into one of the five economic levels: distressed, at-risk, transitional, competitive and attainment counties. Competitive and attainment counties were combined and designated as competitive counties. We used logistic regressions to compare receipt of ADA preventive care recommendations by county economic level, adjusting for respondent demographic, socioeconomic, health and access-to-care factors. Results Compared to the most affluent (competitive) counties, less affluent (distressed and at-risk) counties demonstrated equivalent or higher rates of self-care practices such as daily blood glucose monitoring and daily foot checks. But they showed 40–50% lower uptake of annual foot and eye examinations and 30% lower uptake of diabetes education and pneumococcal vaccinations compared to competitive counties. After adjusting for demographic factors, significant disparities still existed in the uptake of annual foot examinations, annual eye examinations, 2 or more A1c tests per year and pneumococcal vaccinations in distressed and at-risk counties compared to competitive counties. Appalachian counties as a whole were similar to non-Appalachian counties in the uptake of all recommendations with the absolute differences of ≤3%. Conclusions Our results show that there are significant disparities in the uptake of many recommended preventive services between less and more affluent counties in the Appalachian region. PMID:28074140

  17. The radiocarbon hydroxyl technique

    NASA Technical Reports Server (NTRS)

    Campbell, Malcolm J.; Sheppard, John C.

    1994-01-01

    The Radiocarbon Technique depends upon measuring the rate of oxidation of CO in an essentially unperturbed sample of air. The airborne technique is slightly different. Hydroxyl concentrations can be calculated directly; peroxyl concentrations can be obtained by NO doping.

  18. The radiocarbon hydroxyl technique

    NASA Technical Reports Server (NTRS)

    Campbell, Malcolm J.; Sheppard, John C.

    1994-01-01

    The Radiocarbon Technique depends upon measuring the rate of oxidation of CO in an essentially unperturbed sample of air. The airborne technique is slightly different. Hydroxyl concentrations can be calculated directly; peroxyl concentrations can be obtained by NO doping.

  19. Sources and formation mechanisms of carbonaceous aerosol at a regional background site in the Netherlands: insights from a year-long radiocarbon study

    NASA Astrophysics Data System (ADS)

    Dusek, Ulrike; Hitzenberger, Regina; Kasper-Giebl, Anne; Kistler, Magdalena; Meijer, Harro A. J.; Szidat, Sönke; Wacker, Lukas; Holzinger, Rupert; Röckmann, Thomas

    2017-03-01

    We measured the radioactive carbon isotope 14C (radiocarbon) in various fractions of the carbonaceous aerosol sampled between February 2011 and March 2012 at the Cesar Observatory in the Netherlands. Based on the radiocarbon content in total carbon (TC), organic carbon (OC), water-insoluble organic carbon (WIOC), and elemental carbon (EC), we estimated the contribution of major sources to the carbonaceous aerosol. The main source categories were fossil fuel combustion, biomass burning, and other contemporary carbon, which is mainly biogenic secondary organic aerosol material (SOA). A clear seasonal variation is seen in EC from biomass burning (ECbb), with lowest values in summer and highest values in winter, but ECbb is a minor fraction of EC in all seasons. WIOC from contemporary sources is highly correlated with ECbb, indicating that biomass burning is a dominant source of contemporary WIOC. This suggests that most biogenic SOA is water soluble and that water-insoluble carbon stems mainly from primary sources. Seasonal variations in other carbon fractions are less clear and hardly distinguishable from variations related to air mass history. Air masses originating from the ocean sector presumably contain little carbonaceous aerosol from outside the Netherlands, and during these conditions measured carbon concentrations reflect regional sources. In these situations absolute TC concentrations are usually rather low, around 1.5 µg m-3, and ECbb is always very low ( ˜ 0.05 µg m-3), even in winter, indicating that biomass burning is not a strong source of carbonaceous aerosol in the Netherlands. In continental air masses, which usually arrive from the east or south and have spent several days over land, TC concentrations are on average by a factor of 3.5 higher. ECbb increases more strongly than TC to 0.2 µg m-3. Fossil EC and fossil WIOC, which are indicative of primary emissions, show a more moderate increase by a factor of 2.5 on average. An interesting case is

  20. Physical Activity Disparities Between US-born and Immigrant Children by Maternal Region of Origin.

    PubMed

    Kimbro, Rachel Tolbert; Kaul, Bhavika

    2016-04-01

    We examined and compared patterns in physical activity participation for children of US-born and immigrant mothers from seven world geographic regions, and tested whether the physical activity differences were attenuated by socioeconomic status or maternal language proficiency. Using the Early Childhood Longitudinal Study-Kindergarten data (N = 18,850) we utilized logistic regression to predict adequate vigorous physical activity and participation in group and individual sports for kindergarten children. US-born children of US-born parents have significantly higher rates of physical activity compared to immigrant children. Children of Mexican, Southeast Asian, and Caribbean immigrants were especially unlikely to participate in sports. These disparities were not significantly attenuated by socioeconomic status, but accounting for language proficiency reduced some differences between the US-born and immigrant children, particularly for group sports participation. Researchers interested in improving the physical activity patterns of second-generation children should consider the relevance of language barriers in promoting healthy living.

  1. Food insecurity, social capital and perceived personal disparity in a predominantly rural region of Texas: an individual-level analysis

    PubMed Central

    Dean, Wesley R.; Sharkey, Joseph R.

    2011-01-01

    Few studies have addressed the association of food insecurity with place of residence and perceptions of collective social functioning such as perceived social capital and perceived personal disparity. This study assessed the association between food insecurity and measures of perceived personal disparity and perceived social capital in a region of Central Texas, USA comprised of one urban and six rural counties. Food insecurity, perceived social capital, perceived personal disparity, and sociodemographic control measures were derived from the 2006 Brazos Valley Community Health Assessment on an analytic sample of 1,803 adult participants (74% response rate). Robust multinomial regression models examined associations between food insecurity and perceived personal disparity, perceived social capital, education, age, residence in a poor or low-income household, minority group membership, and rural residence. A model was estimated for food insecurity (n = 1803, p < 0.0001). Residents with low social capital, higher levels of perceived personal disparity, rural residence, residence in a low-income or poor household, minority group membership, and lower levels of educational attainment were more likely to experience food insecurity. Rural residence (p = 0.021) was significant only for the comparison between those who never, and those who often experienced food insecurity, and findings for the stratified rural and urban samples were roughly equivalent to the combined sample. Individual level measures of collective social functioning are important correlates of food insecurity. In this study, both perceived personal disparity and perceived social capital play an important role, regardless of rural or urban residence. PMID:21497429

  2. Premature mortality in Belgium in 1993-2009: leading causes, regional disparities and 15 years change.

    PubMed

    Renard, Françoise; Tafforeau, Jean; Deboosere, Patrick

    2014-01-01

    Reducing premature mortality is a crucial public health objective. After a long gap in the publication of Belgian mortality statistics, this paper presents the leading causes and the regional disparities in premature mortality in 2008-2009 and the changes since 1993. All deaths occurring in the periods 1993-1999 and 2003-2009, in people aged 1-74 residing in Belgium were included. The cause of death and population data for Belgium were provided by Statistics Belgium , while data for international comparisons were extracted from the WHO mortality database. Age-adjusted mortality rates and Person Year of Life Lost (PYLL) were calculated. The Rate Ratios were computed for regional and international comparisons, using the region or country with the lowest rate as reference; statistical significance was tested assuming a Poisson distribution of the number of deaths. The burden of premature mortality is much higher in men than in women (respectively 42% and 24% of the total number of deaths). The 2008-9 burden of premature mortality in Belgium reaches 6410 and 3440 PYLL per 100,000, respectively in males and females, ranking 4th and 3rd worst within the EU15. The disparities between Belgian regions are substantial: for overall premature mortality, respective excess of 40% and 20% among males, 30% and 20% among females are observed in Wallonia and Brussels as compared to Flanders. Also in cause specific mortality, Wallonia experiences a clear disadvantage compared to Flanders. Brussels shows an intermediate level for natural causes, but ranks differently for external causes, with less road accidents and suicide and more non-transport accidents than in the other regions. Age-adjusted premature mortality rates decreased by 29% among men and by 22% among women over a period of 15 years. Among men, circulatory diseases death rates decreased the fastest (-43.4%), followed by the neoplasms (-26.6%), the other natural causes (-21.0%) and the external causes (-20.8%). The larger

  3. Pulmonary Embolism Mortality in Brazil from 1989 to 2010: Gender and Regional Disparities

    PubMed Central

    Darze, Eduardo Sahade; Casqueiro, Juliana Borges; Ciuffo, Luisa Allen; Santos, Jessica Mendes; Magalhães, Iuri Resedá; Latado, Adriana Lopes

    2016-01-01

    Background A significant variation in pulmonary embolism (PE) mortality trends have been documented around the world. We investigated the trends in mortality rate from PE in Brazil over a period of 21 years and its regional and gender differences. Methods Using a nationwide database of death certificate information we searched for all cases with PE as the underlying cause of death between 1989 and 2010. Population data were obtained from the Brazilian Institute of Geography and Statistics (IBGE). We calculated age-, gender- and region-specific mortality rates for each year, using the 2000 Brazilian population for direct standardization. Results Over 21 years the age-standardized mortality rate (ASMR) fell 31% from 3.04/100,000 to 2.09/100,000. In every year between 1989 and 2010, the ASMR was higher in women than in men, but both showed a significant declining trend, from 3.10/100,000 to 2.36/100,000 and from 2.94/100,000 to 1.80/100,000, respectively. Although all country regions showed a decline in their ASMR, the largest fall in death rates was concentrated in the highest income regions of the South and Southeast Brazil. The North and Northeast regions, the lowest income areas, showed a less marked fall in death rates and no distinct change in the PE mortality rate in women. Conclusions Our study showed a reduction in the PE mortality rate over two decades in Brazil. However, significant variation in this trend was observed amongst the five country regions and between genders, pointing to possible disparities in health care access and quality in these groups. PMID:26559854

  4. Pulmonary Embolism Mortality in Brazil from 1989 to 2010: Gender and Regional Disparities.

    PubMed

    Darze, Eduardo Sahade; Casqueiro, Juliana Borges; Ciuffo, Luisa Allen; Santos, Jessica Mendes; Magalhães, Iuri Resedá; Latado, Adriana Lopes

    2016-01-01

    A significant variation in pulmonary embolism (PE) mortality trends have been documented around the world. We investigated the trends in mortality rate from PE in Brazil over a period of 21 years and its regional and gender differences. Using a nationwide database of death certificate information we searched for all cases with PE as the underlying cause of death between 1989 and 2010. Population data were obtained from the Brazilian Institute of Geography and Statistics (IBGE). We calculated age-, gender- and region-specific mortality rates for each year, using the 2000 Brazilian population for direct standardization. Over 21 years the age-standardized mortality rate (ASMR) fell 31% from 3.04/100,000 to 2.09/100,000. In every year between 1989 and 2010, the ASMR was higher in women than in men, but both showed a significant declining trend, from 3.10/100,000 to 2.36/100,000 and from 2.94/100,000 to 1.80/100,000, respectively. Although all country regions showed a decline in their ASMR, the largest fall in death rates was concentrated in the highest income regions of the South and Southeast Brazil. The North and Northeast regions, the lowest income areas, showed a less marked fall in death rates and no distinct change in the PE mortality rate in women. Our study showed a reduction in the PE mortality rate over two decades in Brazil. However, significant variation in this trend was observed amongst the five country regions and between genders, pointing to possible disparities in health care access and quality in these groups.

  5. Analyzing Turkey's data from TIMSS 2007 to investigate regional disparities in eighth grade science achievement

    NASA Astrophysics Data System (ADS)

    Erberber, Ebru

    Turkey is expected to be a full member of the European Union (EU) by 2013. In the course of its integration into the EU, Turkey has been simultaneously facing access, quality, and equity issues in education. Over the past decade, substantial progress has been made on increasing the access. However, improving the country's low level of education quality and achieving equity in quality education across the regions continue to be a monumental challenge in Turkey. Most recently, results from the Trends in International Mathematics and Science Study (TIMSS) 2007 indicated that Turkey's educational achievement at the eighth grade, the end of compulsory primary education in Turkey, was far below that of other countries in the EU. Considering Turkey's long standing socioeconomic disparities between the western and eastern parts of the country, the challenges of improving overall education quality are coupled with the challenges of achieving equity in learning outcomes for students across the regions. This dissertation used data from TIMSS 2007 to document the extent of Turkey's regional differences in science achievement at the eighth grade and to investigate factors associated with these differences. Findings from a series of analyses using hierarchical linear models suggested that attempts to increase Turkish students' achievement and close the achievement gaps between regions should target the students in the undeveloped regions, particularly in Southeastern Anatolia and Eastern Anatolia. Designing interventions to improve competency in Turkish and to compensate for the shortcomings of insufficient parental education, limited home educational resources, poor school climate for academic achievement, and inadequate instructional equipment and facilities might be expected to close the regional achievement gaps as well as raise the overall achievement level in Turkey.

  6. Uncovering regional disparity of China's water footprint and inter-provincial virtual water flows.

    PubMed

    Dong, Huijuan; Geng, Yong; Fujita, Tsuyoshi; Fujii, Minoru; Hao, Dong; Yu, Xiaoman

    2014-12-01

    With rapid economic development in China, water crisis is becoming serious and may impede future sustainable development. The uneven distribution of water resources further aggravates such a problem. Under such a circumstance, the concepts of water footprint and virtual water have been proposed in order to respond water scarcity problems. This paper focuses on studying provincial disparity of China's water footprints and inter-provincial virtual water trade flows by adopting inter-regional input-output (IRIO) method. The results show that fast developing areas with larger economic scales such as Guangdong, Jiangsu, Shandong, Zhejiang, Shanghai and Xinjiang had the largest water footprints. The most developed and water scarce areas such as Shanghai, Beijing, Tianjin and Shandong intended to import virtual water, a rational choice for mitigating their water crisis. Xinjiang, Jiangsu, Heilongjiang, Inner Mongolia, Guangxi and Hunan, had the largest per GDP water intensities and were the main water import regions. Another key finding is that agriculture water footprint was the main part in water footprint composition and water export trade. On the basis of these findings, policy implications on agriculture geographical dispersion, consumption behavior changes, trade structure adjustment and water use efficiency improvement are further discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Health Insurance Instability Among Older Immigrants: Region of Origin Disparities in Coverage

    PubMed Central

    Hardy, Melissa

    2015-01-01

    Objectives. We provide a detailed analysis of how the dynamics of health insurance coverage (HIC) at older ages differs among Latino, Asian, and European immigrants in the United States. Method. Using Survey of Income and Program Participation data from the 2004 and 2008 panels, we estimate discrete-time event history models to examine first and second transitions into and out of HIC, highlighting substantial differences in hazard rates among immigrants aged 50–64 from Asia, Latin America, and Europe. Results. We find that the likelihood of having HIC at first observation and the rates of gaining and losing coverage within a relatively short time frame are least favorable for older Latino immigrants, although immigrants from all three regions are at a disadvantage relative to native-born non-Hispanic Whites. This disparity among immigrant groups persists even when lower rates of citizenship, greater difficulty with English, and low-skill job placements are taken into account. Discussion. Factors that have contributed to the lower rates and shorter durations of HIC among older immigrants, particularly those from Latin America, may not be easily resolved by the Affordable Care Act. The importance of region of origin and assimilation characteristics for the risk of being uninsured in later life argues that immigration and health care policy should be jointly addressed. PMID:25637934

  8. Regional Disparities in the Beneficial Effects of Rising CO2 Emissions on Crop Water Productivity

    NASA Technical Reports Server (NTRS)

    Deryng, Delphine; Elliott, Joshua; Folberth, Christian; Meuller, Christoph; Pugh, Thomas A. M.; Boote, Kenneth J.; Conway, Declan; Ruane, Alex C.; Gerten, Dieter; Jones, James W.; Khabarov, Nikolay; Olin, Stefan; Schaphoff, Sibyll; Schmid, Erwin; Yang, Hong; Rosenzweig, Cynthia

    2016-01-01

    Rising atmospheric carbon dioxide concentrations are expected to enhance photosynthesis and reduce crop water use. However, there is high uncertainty about the global implications of these effects for future crop production and agricultural water requirements under climate change. Here we combine results from networks of field experiments and global crop models to present a spatially explicit global perspective on crop water productivity (CWP, the ratio of crop yield to evapotranspiration) for wheat, maize, rice and soybean under elevated carbon dioxide and associated climate change projected for a high-end greenhouse gas emissions scenario. We find carbon dioxide effects increase global CWP by 10[0;47]%-27[7;37]% (median[interquartile range] across the model ensemble) by the 2080s depending on crop types, with particularly large increases in arid regions (by up to 48[25;56]% for rain fed wheat). If realized in the fields, the effects of elevated carbon dioxide could considerably mitigate global yield losses whilst reducing agricultural consumptive water use (4-17%). We identify regional disparities driven by differences in growing conditions across agro-ecosystems that could have implications for increasing food production without compromising water security. Finally, our results demonstrate the need to expand field experiments and encourage greater consistency in modeling the effects of rising carbon dioxide across crop and hydrological modeling communities.

  9. Regional disparities in the beneficial effects of rising CO2 concentrations on crop water productivity

    NASA Astrophysics Data System (ADS)

    Deryng, Delphine; Elliott, Joshua; Folberth, Christian; Müller, Christoph; Pugh, Thomas A. M.; Boote, Kenneth J.; Conway, Declan; Ruane, Alex C.; Gerten, Dieter; Jones, James W.; Khabarov, Nikolay; Olin, Stefan; Schaphoff, Sibyll; Schmid, Erwin; Yang, Hong; Rosenzweig, Cynthia

    2016-08-01

    Rising atmospheric CO2 concentrations ([CO2]) are expected to enhance photosynthesis and reduce crop water use. However, there is high uncertainty about the global implications of these effects for future crop production and agricultural water requirements under climate change. Here we combine results from networks of field experiments and global crop models to present a spatially explicit global perspective on crop water productivity (CWP, the ratio of crop yield to evapotranspiration) for wheat, maize, rice and soybean under elevated [CO2] and associated climate change projected for a high-end greenhouse gas emissions scenario. We find CO2 effects increase global CWP by 10[047]%-27[737]% (median[interquartile range] across the model ensemble) by the 2080s depending on crop types, with particularly large increases in arid regions (by up to 48[25;56]% for rainfed wheat). If realized in the fields, the effects of elevated [CO2] could considerably mitigate global yield losses whilst reducing agricultural consumptive water use (4-17%). We identify regional disparities driven by differences in growing conditions across agro-ecosystems that could have implications for increasing food production without compromising water security. Finally, our results demonstrate the need to expand field experiments and encourage greater consistency in modelling the effects of rising [CO2] across crop and hydrological modelling communities.

  10. Health insurance instability among older immigrants: region of origin disparities in coverage.

    PubMed

    Reyes, Adriana M; Hardy, Melissa

    2015-03-01

    We provide a detailed analysis of how the dynamics of health insurance coverage (HIC) at older ages differs among Latino, Asian, and European immigrants in the United States. Using Survey of Income and Program Participation data from the 2004 and 2008 panels, we estimate discrete-time event history models to examine first and second transitions into and out of HIC, highlighting substantial differences in hazard rates among immigrants aged 50-64 from Asia, Latin America, and Europe. We find that the likelihood of having HIC at first observation and the rates of gaining and losing coverage within a relatively short time frame are least favorable for older Latino immigrants, although immigrants from all three regions are at a disadvantage relative to native-born non-Hispanic Whites. This disparity among immigrant groups persists even when lower rates of citizenship, greater difficulty with English, and low-skill job placements are taken into account. Factors that have contributed to the lower rates and shorter durations of HIC among older immigrants, particularly those from Latin America, may not be easily resolved by the Affordable Care Act. The importance of region of origin and assimilation characteristics for the risk of being uninsured in later life argues that immigration and health care policy should be jointly addressed. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Radiocarbon Dating: An Annotated Bibliography.

    ERIC Educational Resources Information Center

    Fortine, Suellen

    This selective annotated bibliography covers various sources of information on the radiocarbon dating method, including journal articles, conference proceedings, and reports, reflecting the most important and useful sources of the last 25 years. The bibliography is divided into five parts--general background on radiocarbon, radiocarbon dating,…

  12. Radiocarbon Dating: An Annotated Bibliography.

    ERIC Educational Resources Information Center

    Fortine, Suellen

    This selective annotated bibliography covers various sources of information on the radiocarbon dating method, including journal articles, conference proceedings, and reports, reflecting the most important and useful sources of the last 25 years. The bibliography is divided into five parts--general background on radiocarbon, radiocarbon dating,…

  13. Source apportionment of PM2.5 at a regional background site in North China using PMF linked with radiocarbon analysis: insight into the contribution of biomass burning

    NASA Astrophysics Data System (ADS)

    Zong, Zheng; Wang, Xiaoping; Tian, Chongguo; Chen, Yingjun; Qu, Lin; Ji, Ling; Zhi, Guorui; Li, Jun; Zhang, Gan

    2016-09-01

    Source apportionment of fine particles (PM2.5) at a background site in North China in the winter of 2014 was done using statistical analysis, radiocarbon (14C) measurement and positive matrix factorization (PMF) modeling. Results showed that the concentration of PM2.5 was 77.6 ± 59.3 µg m-3, of which sulfate (SO42-) concentration was the highest, followed by nitrate (NO3-), organic carbon (OC), elemental carbon (EC) and ammonium (NH4+). As demonstrated by backward trajectory, more than half of the air masses during the sampling period were from the Beijing-Tianjin-Hebei (BTH) region, followed by Mongolia and the Shandong Peninsula. Cluster analysis of chemical species suggested an obvious signal of biomass burning in the PM2.5 from the Shandong Peninsula, while the PM2.5 from the BTH region showed a vehicle emission pattern. This finding was further confirmed by the 14C measurement of OC and EC in two merged samples. The 14C result indicated that biogenic and biomass burning emission contributed 59 ± 4 and 52 ± 2 % to OC and EC concentrations, respectively, when air masses originated from the Shandong Peninsula, while the contributions fell to 46 ± 4 and 38 ± 1 %, respectively, when the prevailing wind changed and came from the BTH region. The minimum deviation between source apportionment results from PMF and 14C measurement was adopted as the optimal choice of the model exercises. Here, two minor overestimates with the same range (3 %) implied that the PMF result provided a reasonable source apportionment of the regional PM2.5 in this study. Based on the PMF modeling, eight sources were identified; of these, coal combustion, biomass burning and vehicle emission were the main contributors of PM2.5, accounting for 29.6, 19.3 and 15.9 %, respectively. Compared with overall source apportionment, the contributions of vehicle emission, mineral dust, coal combustion and biomass burning increased when air masses came from the BTH region, Mongolia and the Shandong

  14. PRIME Lab Radiocarbon Measurements

    NASA Astrophysics Data System (ADS)

    Hillegonds, D. J.; Mueller, K. A.; Ma, X.; Lipschutz, M. E.

    1996-03-01

    The Purdue Rare Isotope Measurement Laboratory (PRIME Lab) is one of three NSF national facilities for accelerator mass spectrometry (AMS), and is the only one capable of determining six cosmogenic radionuclides: 10Be, 14C, 26Al, 36Cl, 41Ca, and 129I. This abstract describes the current status of the radiocarbon analysis program at PRIME Lab.

  15. Regional disparity in hygienic behaviors of Iranian children and adolescents: The CASPIAN-IV study

    PubMed Central

    Qorbani, Mostafa; Kelishadi, Roya; Djalalinia, Shirin; Motlagh, Mohammad Esmaeil; Kasaeian, Amir; Ardalan, Gelayol; Shafiee, Gita; Safari, Omid; Heshmat, Ramin; Baradaran Mahdavi, Sadegh

    2016-01-01

    Background: This study aimed to assess the pattern of hygienic behaviors of Iranian children and adolescents at national and sub-national levels according to the socioeconomic status (SES) of their living region. Methods: Data were obtained from the fourth national school-based surveillance survey entitled, "CASPIANIV study" (2011-2012). It was conducted among 14,880 students, aged 6-18 years, who were selected by multistage random cluster sampling from 30 provinces in Iran. We used the World Health Organization Global School-based Student Health Survey (WHO- GSHS) questionnaire. Data were analyzed at national and subnational levels according to the SES of the living region. Results: Overall, 13,486 students (49.2% girls) with the mean (SD) age of 12.50 (3.36) years participated in this study (participation rate: 90.6%). At the national level, 67.21% of the participants had daily tooth brushing, the frequencies for always washing hands after using the toilet, washing hands before eating, and washing hands with soap in school were 85.61%, 56.53%, and 50.32%, respectively. The frequency of daily tooth brushing had no significant difference according to the SES of the living region. In all of the categories of washing hands, the West region (second high SES rank) had the highest frequency of hygienic behaviors (p<0.001). Conclusion: In general, the reported hygienic behaviors were at an acceptable level; however, a large comprehensive health-promoting plan should be considered for all children and adolescents at the national and subnational levels taking into account the disparities according to their SES. PMID:28210596

  16. Food insecurity, social capital and perceived personal disparity in a predominantly rural region of Texas: an individual-level analysis.

    PubMed

    Dean, Wesley R; Sharkey, Joseph R

    2011-05-01

    Few studies have addressed the association of food insecurity with place of residence and perceptions of collective social functioning such as perceived social capital and perceived personal disparity. This study assessed the association between food insecurity and measures of perceived personal disparity and perceived social capital in a region of Central Texas, USA comprised of one urban and six rural counties. Food insecurity, perceived social capital, perceived personal disparity, and sociodemographic control measures were derived from the 2006 Brazos Valley Community Health Assessment on an analytic sample of 1803 adult participants (74% response rate). Robust multinomial regression models examined associations between food insecurity and perceived personal disparity, perceived social capital, education, age, residence in a poor or low-income household, minority group membership, and rural residence. A model was estimated for food insecurity (n = 1803, p < 0.0001). Residents with low social capital, higher levels of perceived personal disparity, rural residence, residence in a low-income or poor household, minority group membership, and lower levels of educational attainment were more likely to experience food insecurity. Rural residence (p = 0.021) was significant only for the comparison between those who never, and those who often experienced food insecurity, and findings for the stratified rural and urban samples were roughly equivalent to the combined sample. Individual level measures of collective social functioning are important correlates of food insecurity. In this study, both perceived personal disparity and perceived social capital play an important role, regardless of rural or urban residence. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. The electrification of Nova Scotia, 1884--1973: Technological modernization as a response to regional disparity

    NASA Astrophysics Data System (ADS)

    King, Lionel Bradley

    This dissertation investigates local attempts to use technology as a force for regional rehabilitation in the economically-depressed Maritime region of Canada. At the time of Confederation in 1867, the Maritime province of Nova Scotia was prosperous, progressive, and cultured. By the end of the 1910s, the province had entered a long period of economic and social decline. Recent historiography has shown that, far from passively accepting their fate, Nova Scotians and other Maritimers, actively resisted marginalization with political, cultural, or social action. The thesis expands upon that literature by exploring technology-based strategies of provincial rehabilitation using Thomas P. Hughes's systems perspective and David E. Nye's semiotic approach. In doing so, it applies methods from the social constructivist school of the history of technology to the larger concerns of Maritime Canadian historiography. In large part, the North American culture of technology determined the ways in which Nova Scotians applied technological solutions to provincial concerns. Technology has long been central to the Western idea of progress. As the "high technology" of the late nineteenth and early twentieth centuries, electricity reinforced that view: its ephemeral nature and silent efficiency led people to endow it with transformative, even mystical, powers. As a result, Nova Scotians, adopted a program of electrical modernization in the late 1910s as a remedy for regional disparity. The Nova Scotia government's first step was the creation of an Ontario-style hydroelectric commission designed to bring order to the province's fragmented and inefficient electrical network. Over the next few decades, the Nova Scotia Power Commission implemented rural electrification, home modernization, and regional system-building models that had already proven successful in Ontario and the United States. The system-building philosophies behind these programs were adapted to local conditions and

  18. Insights into soil carbon dynamics across climatic and geologic gradients from time-series and fraction-specific radiocarbon analysis

    NASA Astrophysics Data System (ADS)

    van der Voort, Tessa Sophia; Hagedorn, Frank; Zell, Claudia; McIntyre, Cameron; Eglinton, Tim

    2016-04-01

    Understanding the interaction between soil organic matter (SOM) and climatic, geologic and ecological factors is essential for the understanding of potential susceptibility and vulnerability to climate and land use change. Radiocarbon constitutes a powerful tool for unraveling SOM dynamics and is increasingly used in studies of carbon turnover. The complex and inherently heterogeneous nature of SOM renders it challenging to assess the processes that govern SOM stability by solely looking at the bulk signature on a plot-scale level. This project combines bulk radiocarbon measurements on a regional-scale spanning wide climatic and geologic gradients with a more in-depth approach for a subset of locations. For this subset, time-series and carbon pool-specific radiocarbon data has been acquired for both topsoil and deeper soils. These well-studied sites are part of the Long-Term Forest Ecosystem Research (LWF) program of the Swiss Federal Institute for Forest, Snow and Landscape research (WSL). Statistical analysis was performed to examine relationships of radiocarbon signatures with variables such as temperature, precipitation and elevation. Bomb-curve modeling was applied determine carbon turnover using time-series data. Results indicate that (1) there is no significant correlation between Δ14C signature and environmental conditions except a weak positive correlation with mean annual temperature, (2) vertical gradients in Δ14C signatures in surface and deeper soils are highly similar despite covering disparate soil-types and climatic systems, and (3) radiocarbon signatures vary significantly between time-series samples and carbon pools. Overall, this study provides a uniquely comprehensive dataset that allows for a better understanding of links between carbon dynamics and environmental settings, as well as for pool-specific and long-term trends in carbon (de)stabilization.

  19. Vulcanism and Radiocarbon Dates

    DOE R&D Accomplishments Database

    Libby, L. M.; Libby, W. F.

    1972-10-01

    We consider whether the long term perturbation of radiocarbon dates, which is known to be approximately a sin function of period about 8000 years and amplitude of about 8% peak-to-peak, could have been caused in any major part by vulcanism. We conclude that this is not the case. On the contrary, present day volcanoes are a far less important source of inert CO{sub 2} (about 100 fold less) than is man's burning of fossil fuels which has caused the Suess dilution of about 2%. (auth)

  20. Radiocarbon Dating, Memories, and Hopes

    DOE R&D Accomplishments Database

    Libby, W. F.

    1972-10-01

    The history of radiocarbon dating from 1939 to the present is reviewed. The basic principles of radiocarbon dating are that cosmic rays make living things radioactive with {sup 14}C to a certain level fixed by the environment and that at death the intake of food stops so no replenishment of the {sup 14}C steadily lost by the immutable decay occurs. Therefore measurement of the degree of decay gives the time lapse since death, i.e., the radiocarbon age. The equipment developed and experiments performed to measure the specific activity of specimens to be dated are described. The results obtained by world-wide experimenters are discussed. These showed that on simultaneity radiocarbon dating is apparently reliable but that absolute dates may be incorrect by as much as 600 to 700 y. The value of radiocarbon dating to archaeologists, geologists, climatologists, and historians is stressed. (LCL)

  1. Assessing the disparity in spatial access to hospital care in ethnic minority region in Sichuan Province, China.

    PubMed

    Wang, Xiuli; Pan, Jay

    2016-08-17

    There is a great disparity in spatial accessibility to hospital care between ethnic minority and non-minority regions in China. Being one of the basic social demands, spatial access to hospital care in minority regions draws increasing attention in China in recent years. We performed this study to have a better understanding of spatial access to hospital care in ethnic minority region in China, and to guide the allocation of government investment in the future. Sichuan Province, southwest of China was selected as a sample to examine the difference in hospital access between ethnic minority and non-minority region in China. We applied the shortest path analysis and the enhanced two-step floating catchment area (E2SFCA) method under ArcGIS 9.3 environment. In Sichuan, healthcare access in ethnic minority region is worse than in non-minority region in terms of time to hospital and the value of spatial accessibility. There is relatively greater inequality in access to doctors and health professionals than in access to hospital beds. In ethnic minority region, the balance between primary, secondary, and tertiary hospitals, as well as between public and private hospitals, is less even, compared with the non-minority region. The disparity within ethnic minority region is larger than in non-minority region. The combination of shortest path analysis and E2SFCA method is superior to the traditional county ratio method in assessing spatial access to healthcare. Compared to the non-minority region, ethnic minority region rely more heavily on government investment to provide healthcare. In ethnic minority region, the current distribution of primary, secondary and tertiary hospitals is inappropriate, and there is an urgent shortage of healthcare personnel. We therefore recommend that the government use preferential policies to encourage more social capital investment in ethnic minority region, use government investment as a supplement to build a more equitable healthcare market

  2. New biomedical applications of radiocarbon

    SciTech Connect

    Davis, J.C.

    1990-12-01

    The potential of accelerator mass spectrometry (AMS) and radiocarbon in biomedical applications is being investigated by Lawrence Livermore National Laboratory (LLNL). A measurement of the dose-response curve for DNA damage caused by a carcinogen in mouse liver cells was an initial experiment. This demonstrated the sensitivity and utility of AMS for detecting radiocarbon tags and led to numerous follow-on experiments. The initial experiment and follow-on experiments are discussed in this report. 12 refs., 4 figs. (SM)

  3. Polymorphisms in the umuDC region of Escherichia species. [Escherichia coli; Escherichia alkalescens; Escherichia dispar; Escherichia aurescens

    SciTech Connect

    Sedgwick, S.G.; Robson, M.; Malik, F.

    1988-04-01

    The umuDC operon of Escherichia coli encodes mutagenic DNA repair. The umuDC regions of multiple isolates of E. coli, E. alkalescens, and E. dispar and a single stock of E. aurescens were mapped by nucleotide hybridization. umuDC is located at one end of a conserved tract of restriction endonuclease sites either 12.5 or 14 kilobase pairs long. Rearrangements, including possible deletions, were seen in the polymorphic DNA flanking the conserved tract. Restriction site polymorphisms were not found around the DNA repair gene recA or polA. The junctions of the conserved region contain direct repeats of nucleotide sequences resembling the termini of the Tn3 group of transposons. Possible mechanisms for the generation of these variants are discussed.

  4. Geographic disparities in heart disease and stroke mortality among black and white populations in the Appalachian region.

    PubMed

    Halverson, Joel A; Barnett, Elizabeth; Casper, Michele

    2002-01-01

    In this paper, we examine geographic and racial/ethnic differences in heart disease and stroke mortality in the Appalachian region. Initial comparisons are made between national rates for heart disease and stroke mortality and those for the Appalachian region. County-level analyses were performed to examine the relative mortality experience of populations in Appalachian counties compared to other counties in the United States and to assess the degree of geographic disparity in mortality from heart disease and stroke among these race/ethnic and gender groups within Appalachia. The Appalachian region exhibits higher rates of both heart disease and stroke mortality for all race/ethnic, gender, and age groups examined. We found that many counties in the Appalachian region endure a considerable burden of the national excess in both heart disease and stroke mortality, and these counties tend to be aggregated in particular areas as opposed to being dispersed regionwide. Finally, we compare 2 groups of counties in Appalachia based on the designation as an "economically distressed county," defined by the Appalachian Regional Commission. As a group, distressed counties in Appalachia exhibit higher rates of both heart disease and stroke mortality than the rest of Appalachia.

  5. Catching Up or Falling Behind? Continuing Wealth Disparities for Immigrants to Canada by Region of Origin and Cohort.

    PubMed

    Maroto, Michelle; Aylsworth, Laura

    2016-11-01

    This paper investigates wealth disparities among first-generation immigrants using data from the 2012 Survey of Financial Security. We apply logistic and linear regression models to estimate disparities in homeownership and household equivalent net worth by immigrant status, region of origin, and time since arrival. By focusing on immigrant families from different regions who entered Canada at different points in time, this research applies theories related to assimilation, human capital, and structural barriers to wealth. Our findings demonstrate that even though many immigrant families transition into homeownership and grow their wealth over time, certain first-generation immigrant groups continue to experience wealth disparities many years after their arrival to Canada. In particular, immigrant families from African, Asian, and Middle Eastern countries experienced the largest wealth gaps. Cet article examine les disparités de richesse entre les immigrants de première génération en utilisant les données de l'Enquête 2012 sur la sécurité financière. Nous appliquons des modèles de régression logistique et linéaire pour estimer les disparités dans la propriété et valeur nette des ménages équivalente par le statut d'immigrant, la région d'origine, et le temps écoulé depuis leur arrivée. En se concentrant sur les familles d'immigrants de différentes régions qui sont entrés au Canada à différents points dans le temps, cette recherche applique les théories liées à l'assimilation, le capital humain, et les obstacles structurels à la richesse. Nos résultats démontrent que même si de nombreuses familles d'immigrants transition vers la propriété et de croître leur richesse au fil du temps, certains groupes d'immigrants de première génération continuent d'éprouver des disparités de richesse de nombreuses années après leur arrivée au Canada. En particulier, les familles d'immigrants d'Afrique, d'Asie, et les pays du Moyen-Orient ont

  6. Cancer Disparities

    Cancer.gov

    Basic information about cancer disparities in the U.S., factors that contribute to the disproportionate burden of cancer in some groups, and examples of disparities in incidence and mortality among certain populations.

  7. Age, Race and Regional Disparities in Colorectal Cancer Incidence Rates in Georgia between 2000 and 2012

    PubMed Central

    Yoo, Wonsuk; De, Subhendu; Wilkins, Thad; Smith, Selina A.; Blumenthal, Daniel

    2016-01-01

    Colorectal cancer (CRC) incidence rates and mortality have been decreasing in the United States. Currently, states in the South have the smallest reduction in CRC mortality. The trends of CRC incidence rates in Georgia in comparison to the United States have not been investigated. We analyzed age-adjusted incidence rates of CRC in Georgia and the United States from 2000 to 2012 using data from SEER 18 registries. Age-adjusted incidence rates (95% CI) were calculated as cases per 100,000 to the 2000 US Standard population. CRC incidence rates were calculated for groupings based on age at time of diagnosis, race, sex, and geographic location within Georgia. Incidence rates were higher in males compared to females in Georgia. In Georgians age 50–64, incidence rates were higher compared to the US, while those ages 65+ displayed lower incidence rates. Black Georgians age 50–64 generally exhibited higher incidence rates of CRC and lower rates of decrease in incidence compared to other races in Georgia. Asian/Pacific Islander females age 50–64 in Georgia exhibited an increasing trend in incidence rate. Whites and blacks Georgians age 50–64 displayed higher incidence rates compared to the US, while Asian/Pacific Islanders displayed lower incidence rates. Greater incidence rates of CRC in rural and Greater Georgia were seen across all races when compared to overall rates in Georgia. Efforts should be made to address disparities in Georgia based on race and geographic location. Increased screening by colonoscopy or fecal occult blood testing, reduction of risk factors and promotion of healthy lifestyles can reduce CRC incidence rates. PMID:27042701

  8. Regional disparities in psychiatric distress, violent behavior, and life satisfaction in Iranian adolescents: the CASPIAN-III study.

    PubMed

    Ahadi, Zeinab; Qorbani, Mostafa; Kelishadi, Roya; Ardalan, Gelayol; Taslimi, Mahnaz; Mahmoudarabi, Minoosadat; Motlagh, Mohammad Esmaeil; Asayesh, Hamid; Shafiee, Gita; Larijani, Bagher; Heshmat, Ramin

    2014-01-01

    The purpose of this study was to assess the prevalence of violence behaviors, psychiatric distress, and life satisfaction among 10- to 18-year-old Iranian adolescents at national and regional disparities. In this national survey, 5570 students of age 10 to 18 years from urban and rural regions of 27 provinces of Iran were selected through stratified multistage sampling method. Violence behaviors, psychiatric distress, and life satisfaction were assessed by a questionnaire that was prepared based on WHO global school-based student health survey and the WHO-stepwise approach to noncommunicable diseases (Tools version 9.5). The country classification into 4 subnational regions was done based on combination of geography and socioeconomic status (SES). The data were analyzed by the SPSS software. The prevalence of emotional, depressive, and anxiety problem among Iranian students was 17.7%, 16.3%, and 5.7%, respectively. The percentage of emotional and depressive problem differed significantly between different SES distress (p value <.001). The prevalence of bullying, victim, and physical fight was 27.1%, 32.7%, and 50.6% among students aged 10 to 18 years, respectively. Bullying and victim experience were linearly associated with regions' SES. Students who were living in the north-northeast region had maximum self-rated health and life satisfaction in Iran. The results declared that psychiatric distress was more frequent in high SES distress, whereas violence behavior was more frequent in the lowest SES distress. Therefore, in communities with large variations in health and SES in regional level, health policies for primordial and primary prevention of mental and behavioral distress have to be made at regional levels.

  9. [Prevalence of health problems in the Gazel (EDF-GDF) cohort: regional distribution and disparities].

    PubMed

    Tran, P D; Leclerc, A; Chastang, J F; Goldberg, M

    1994-01-01

    This study deals with regional differences in annual prevalence of 44 declared diseases or clinical disorders in 1989 in GAZEL cohort participants from "Electricité de France-Gaz de France" company. The studied sample consisted of 20,325 people, from 35 to 50 years old, living in France, who answered to a mail questionnaire in 1989. The collected data from one year were analysed. An overall "regional effect" was searched about every listed disease in the questionnaire. For this purpose, a logistic model, controlling for age and sex, was used. For comparing prevalence of a disease in one region with average prevalence, an odds ratio (OR) was calculated: it was defined here as the ratio of disease odd in the region to the average French odd. The regional effect was studied in greater detail for five diseases, making allowance for extra factors of adjustment (tobacco and alcohol consumption, Quetelet index, salary category, number of declared diseases). The regional effect remained significative for four diseases: hypertension with OR from 1.26 to 1.68 in northern regions, and from 0.63 to 0.75 in southeastern ones; osteoarthrosis with OR lower than 1 in western regions (0.60 to 0.79), and larger in the South (1.24 to 1.46); hyperthyroidism, goiter with OR elevated in Midi-Pyrénées (2.91) and Lorraine (1.82) [corrected]; renal stones with OR high in the South (1.85 in Provence Riviera). These results can be compared to known observations about geographical differences in mortality. They also suggest persistence of hazardous areas for some diseases.

  10. Implementing colorectal cancer screening in community health centers: addressing cancer health disparities through a regional cancer collaborative.

    PubMed

    Taplin, Stephen H; Haggstrom, David; Jacobs, Tracy; Determan, Ada; Granger, Jennifer; Montalvo, Wanda; Snyder, William M; Lockhart, Susan; Calvo, Ahmed

    2008-09-01

    The population served by Federally Qualified Health Centers (FQHCs) has lower levels of cancer screening compared with the general population and suffers a disproportionate cancer burden. To address these disparities, 3 federal agencies and a primary care association established and tested the feasibility of a Regional Cancer Collaborative (RCC) in 2005. RCC faculty implemented a learning model to improve cancer screening across 4 FQHCs that met explicit organizational readiness criteria. Regional faculty trained "care process leaders," who worked with primary care teams to plan and implement practice changes. FQHCs monitored progress across the following measures of screening implementation: self-management goal-setting; number and percent screened for breast, cervical, and colorectal cancer; percent timely results notification; and percent abnormal screens evaluated within 90 days. Progress and plans were reviewed in regular teleconferences. FQHCs were encouraged to create local communities of practice (LCOP) involving community resources to support cancer screening and to participate in a monthly teleconference that linked the LCOPs into a regional community of practice. Summary reports and administrative data facilitated a process evaluation of the RCC. chi test and test of trends compared baseline and follow-up screening rates. The RCC taught the collaborative process using process leader training, teleconferences, 2 regional meetings, and local process improvement efforts. All organizations created clinical tracking capabilities and 3 of the 4 established LCOPs, which met monthly in an regional community of practice. Screening documentation increased for all 3 cancers from 2005 to 2007. Colorectal cancer screening increased from 8.6% to 21.2%. A regional plan to enable collaborative learning for cancer screening implementation is feasible, and improvements in screening rates can occur among carefully selected organizations.

  11. Breast cancer screening disparities among immigrant women by world region of origin: a population-based study in Ontario, Canada.

    PubMed

    Vahabi, Mandana; Lofters, Aisha; Kumar, Matthew; Glazier, Richard H

    2016-07-01

    Rates of mammography screening for breast cancer are disproportionately low in certain subgroups including low-income and immigrant women. The purpose of the study was to examine differences in rates of appropriate breast cancer screening (i.e., screening mammography every 2 years) among Ontario immigrant women by world region of origin and explore the association between appropriate breast cancer screening among these women groups and individual and structural factors. A cohort of 183,332 screening-eligible immigrant women living in Ontario between 2010 and 2012 was created from linked databases and classified into eight world regions of origin. Appropriate screening rates were calculated for each region by age group and selected sociodemographic, immigration, and healthcare-related characteristics. The association between appropriate screening across the eight regions of origin and selected sociodemographic, immigration, and health-related characteristics was explored using multivariate Poisson regression. Screening varied by region of origin, with South Asian women (48.5%) having the lowest and Caribbean and Latin American women (63.7%) the highest cancer screening rates. Factors significantly associated with lower screening across the world regions of origin included living in the lowest income neighborhoods, having a refugee status, being a new immigrant, not having a regular physical examination, not being enrolled in a primary care patient enrollment model, having a male physician, and having an internationally trained physician. Multiple interventions entailing cross-sector collaboration, promotion of patient enrollment models, community engagement, comprehensive and intensive outreach to women, and knowledge translation and transfer to physicians should be considered to address screening disparities among immigrant population. Consideration should be given to design and delivery of culturally appropriate and easily accessible cancer screening programs

  12. Ischaemic heart disease deaths in Brazil: current trends, regional disparities and future projections.

    PubMed

    Baena, Cristina P; Chowdhury, Rajiv; Schio, Nicolle Amboni; Sabbag, Ary Elias; Guarita-Souza, Luiz Cesar; Olandoski, Marcia; Franco, Oscar H; Faria-Neto, José Rocha

    2013-09-01

    To quantify the trend of ischaemic heart disease (IHD) deaths in Brazil during the last decade (2000-2010) for various population characteristics and to forecast the upcoming mortality trends across regions in Brazil until the year 2015. Nationwide comparative observational study. The population studied encompassed all adult residents (≥ 20 years) living in five Brazilian regions between 2000 and 2010. Demographic, economic and mortality data were obtained from Brazilian National Mortality Data System and National Applied Economics Research Institute. Subnotified deaths were redistributed proportionally to IHD deaths. Age-standardised mortality rates (ASMRs) per 100 000 inhabitants, by sex and region, were calculated employing a standard Brazilian population and constructing multivariate regression models to quantify and to project temporal trends. Absolute numbers of death due to IHD and region-specific death rates in Brazil by age and sex. During the study period, 627 786 men and 452 690 women died due to IHD in Brazil. ASMR trends across all regions for men and women converged, driven by a declining trend in the South and Southeast and an opposite incline in the North and Northeast (p < 0.05). Future projections demonstrated potential widening of the observed North-South gap in coming years. The IHD death trend in Brazil has changed from a decline to a stagnant state. However, a significant discrepancy in mortality trends exists between the northern and southern regions, which is likely to widen further. Reappraisal of the public health policies tailored to populations with diverse socioeconomic structures is urgently required.

  13. Radiocarbon-based Turnover Time Estimates of Soil Organic Carbon in a Cool-temperate Deciduous Forest in Asian Monsoon Region

    NASA Astrophysics Data System (ADS)

    Kondo, M.; Uchida, M.; Ohtsuka, T.; Murayama, S.; Shirato, Y.; Shibata, Y.

    2007-12-01

    Significantly more carbon is stored in the soils than in present in the atmosphere. Although the potential for C storage rates may change in the future as climate change progresses, the dynamics of soil carbon is unknown enough. We separated two density fractions on the soil down to 75 cm depth and estimated turnover time of these SOC fractions for volcanic ash soils in a cool-temperate deciduous forest in Japan, at one of AsiaFlux monitoring sites. According to the eddy-covariance based and biometric based carbon flux measurements over 10 years long in this site, this ecosystem is storing C (net ecosystem exchange (NEE): -2.4 tC ha-1 year- 1). However, the partitioning of C storage among vegetation and soils at this site is unknown. Measurements of carbon and radiocarbon (14C) inventory were used to determine the turnover time of two fractions of SOM: humified low density material < 2 g/cc and high density or mineral-associated organic matter > 2 g/cc. Total SOC stocks down to the depth of 75 cm were 26.2 kg C m-2, with the majority of SOC (52 percent) in the AB horizon (20 - 50 cm). Storage of SOC in our site was larger and differed considerably from that in other temperate forests in North America and Europe. The major part of the SOC (74 percent) was carbon in low density fraction. In the AB horizon, carbon in low density fraction accounted for 75 percent of the total SOC. The age of this fraction in lower AB horizon (35 - 50 cm) was significantly old (2490 years) as well as high density fraction (2930 years), although this fraction seems to consist of labile carbon. Turnover times in all fractions are investigated for some layers in the soil depth of 75cm, as well as fine roots, low density humified material and carbon associated with minerals. Turnover times in both fractions increased with soil depth and 11-2780 year for low density fractions and 610- 3740 year for high density fractions. The turnover times of SOC were relatively long (1760 - 3740 years) in

  14. Evidence of economic regularities and disparities of Italian regions from aggregated tax income size data

    NASA Astrophysics Data System (ADS)

    Cerqueti, Roy; Ausloos, Marcel

    2015-03-01

    This paper discusses the size distribution-in economic terms-of the Italian municipalities over the period 2007-2011. Yearly data are rather well fitted by a modified Lavalette law, while Zipf-Mandelbrot-Pareto law seems to fail in this doing. The analysis is performed either at a national as well as at a local (regional and provincial) level. Deviations are discussed as originating in so called king and vice-roy effects. Results confirm that Italy is shared among very different regional realities. The case of Lazio is puzzling.

  15. Back to the Basics: Socio-Economic, Gender, and Regional Disparities in Canada's Educational System

    ERIC Educational Resources Information Center

    Edgerton, Jason D.; Peter, Tracey; Roberts, Lance W.

    2008-01-01

    This study reassessed the extent to which socio-economic background, gender, and region endure as sources of educational inequality in Canada. The analysis utilized the 28,000 student Canadian sample from the data set of the OECD's 2003 "Programme for International Student Assessment (PISA)". Results, consistent with previous findings,…

  16. Social determinants of malnutrition among Serbian children aged <5 years: ethnic and regional disparities.

    PubMed

    Brcanski, Jelena; Jović-Vraneš, Aleksandra; Marinković, Jelena; Favre, Dragana

    2014-10-01

    To assess the association between growth indicators of Serbian children aged <5 years of Roma and non-Roma populations and social determinants of health. This study used a cross-sectional secondary data analysis design to measure national and Roma population samples from the MICS 4 (UNICEF) performed in 2010 in Serbia. A total of 4,978 questionnaires were observed with children aged <5 years. Logistic regression analysis was performed to identify association between social determinants of health and growth indicators. Roma children were more than three times more likely to exhibit stunted and/or severely stunted than non-Roma children from the lowest wealth quintile. Non-Roma children residing outside of the Belgrade region had a lower risk of stunted compared to children residing within the Belgrade region, while the risk of stunted among Roma children was nearly twofold greater than those residing in southern and eastern Serbia than in the Belgrade region. Our findings clarified the necessity to establish ethnically and regionally sensitive programs to solve the malnutrition problems.

  17. Climate, crops and lacking data underlie regional disparities in the CO2 fertilization effect

    NASA Astrophysics Data System (ADS)

    Rosenthal, David M.; Tomeo, Nicholas J.

    2013-09-01

    The recent study by McGrath and Lobell (2013 Environ. Res. Lett. 8 014054) assesses the interaction of a changing climate and the carbon dioxide fertilization effect (CFE) on crop productivity. By accounting for the differential response of individual crops and using a finer geographic scale to assess climate effects on crops they have found that previous estimates of the CFE have likely overestimated future yields in some regions while underestimating yields in others. While this work improves our estimates of potential crop yields in an elevated CO2 atmosphere, it also highlights knowledge gaps regarding the response of major crops to the effects of elevated CO2 under the sub-optimal growing conditions predicted for many regions in the future.

  18. Similarity and disparity in regional climate response between greenhouse gas and aerosol forcing

    NASA Astrophysics Data System (ADS)

    Xie, S. P.; WANG, H.

    2016-12-01

    Spatial distribution is quite distinct between anthropogenic changes in greenhouse gas and aerosols. Regional patterns of climate response bear a striking similarity between the two forcing types, however, due to fast atmospheric adjustments and slow ocean-atmosphere interactions. With strong spatial variations, aerosol forcing is more effective in inducing atmospheric circulation and rainfall response than the greenhouse gas forcing. The opposing polarity and similar pattern in regional response between the two forcing agents suppress historical rainfall change, rendering the detection difficult. A close comparison of single forcing experiments with coupled ocean-atmosphere models reveals substantial differences in climate response to different radiative forcing, especially in the north-south direction. The aerosol forcing, larger in the Northern than Southern Hemispheres, induces an interhemispheric Hadley circulation. From ship observations and reanalyses, we detected a robust change in the zonal mean cross-equatorial wind over the past 60 years, accompanied by physically consistent changes in atmospheric pressure and marine cloud cover. Single-forcing experiments indicate that the observed change in cross-equatorial wind is a fingerprint of aerosol forcing. This zonal mean mode follows the evolution of global aerosol forcing that is distinct from the well-known regional changes in the Atlantic sector.

  19. Merging Disparate Data Sources Into a Paleoanthropological Geodatabase for Research, Education, and Conservation in the Greater Hadar Region (Afar, Ethiopia)

    NASA Astrophysics Data System (ADS)

    Campisano, C. J.; Dimaggio, E. N.; Arrowsmith, J. R.; Kimbel, W. H.; Reed, K. E.; Robinson, S. E.; Schoville, B. J.

    2008-12-01

    Understanding the geographic, temporal, and environmental contexts of human evolution requires the ability to compare wide-ranging datasets collected from multiple research disciplines. Paleoanthropological field- research projects are notoriously independent administratively even in regions of high transdisciplinary importance. As a result, valuable opportunities for the integration of new and archival datasets spanning diverse archaeological assemblages, paleontological localities, and stratigraphic sequences are often neglected, which limits the range of research questions that can be addressed. Using geoinformatic tools we integrate spatial, temporal, and semantically disparate paleoanthropological and geological datasets from the Hadar sedimentary basin of the Afar Rift, Ethiopia. Applying newly integrated data to investigations of fossil- rich sediments will provide the geospatial framework critical for addressing fundamental questions concerning hominins and their paleoenvironmental context. We present a preliminary cyberinfrastructure for data management that will allow scientists, students, and interested citizens to interact with, integrate, and visualize data from the Afar region. Examples of our initial integration efforts include generating a regional high-resolution satellite imagery base layer for georeferencing, standardizing and compiling multiple project datasets and digitizing paper maps. We also demonstrate how the robust datasets generated from our work are being incorporated into a new, digital module for Arizona State University's Hadar Paleoanthropology Field School - modernizing field data collection methods, on-the-fly data visualization and query, and subsequent analysis and interpretation. Armed with a fully fused database tethered to high-resolution satellite imagery, we can more accurately reconstruct spatial and temporal paleoenvironmental conditions and efficiently address key scientific questions, such as those regarding the

  20. Mississippi Communities for Healthy Living: Implementing a nutrition intervention effectiveness study in a rural health disparate region.

    PubMed

    Connell, Carol L; Thomson, Jessica L; Huye, Holly F; Landry, Alicia S; Crook, LaShaundrea B; Yadrick, Kathy

    2015-05-01

    health disparate region requires flexibility in adapting the recruitment, retention, and data collection procedures while maintaining a high level of scientific rigor. Negligible research participation effects, such as measurement reactivity, were noted in this population. However, further research is needed to identify methods to successfully recruit and retain Caucasian females to participate in community-based nutrition interventions in this region. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Fuzzy-Klassen Model for Development Disparities Analysis based on Gross Regional Domestic Product Sector of a Region

    NASA Astrophysics Data System (ADS)

    Ai, Tb.; Wardoyo, Retantyo

    2015-08-01

    Analysis of regional development imbalances quadrant has a very important meaning in order to see the extent of achievement of the development of certain areas as well as the difference. Factors that could be used as a tool to measure the inequality of development is to look at the average growth and development contribution of each sector of Gross Regional Domestic Product (GRDP) based on the analyzed region and the reference region. This study discusses the development of a model to determine the regional development imbalances using fuzzy approach system, and the rules of typology Klassen. The model is then called fuzzy-Klassen. Implications Product Mamdani fuzzy system is used in the model as an inference engine to generate output after defuzzyfication process. Application of MATLAB is used as a tool of analysis in this study. The test a result of Kota Cilegon is shows that there are significant differences between traditional Klassen typology analyses with the results of the model developed. Fuzzy model-Klassen shows GRDP sector inequality Cilegon City is dominated by Quadrant I (K4), where status is the sector forward and grows exponentially. While the traditional Klassen typology, half of GRDP sector is dominated by Quadrant IV (K4) with a sector that is lagging relative status.

  2. Regional Disparities in Mortality after Ischemic Heart Disease in a Brazilian State from 2006 to 2010

    PubMed Central

    de Andrade, Luciano; Zanini, Vanessa; Batilana, Adelia Portero; de Carvalho, Elias Cesar Araujo; Pietrobon, Ricardo; Nihei, Oscar Kenji; de Barros Carvalho, Maria Dalva

    2013-01-01

    Background High technology in the field of interventional cardiology applied in tertiary hospitals has brought enormous benefits in the treatment of ischemic heart disease (IHD). However, IHD mortality rates remain high. We analyzed the relationship between IHD mortality rate and the socioeconomic, demographic, and geographic conditions in 399 cities in Parana state, Brazil, from 2006 to 2010. Methods and Results Data were obtained from the Mortality Information System and the Brazilian Institute of Geography and Statistics and evaluated through Exploratory Spatial Data Analysis. GeoDa™ was used to analyze 29.351 deaths across 399 cities. We found a positive spatial autocorrelation regarding IHD mortality (I = 0.5913, p = 0.001). There was a significant positive association between each of three socioeconomic and demographic indicators and IHD mortality rate: Population Elderly Index (I = 0.3436), Illiteracy Rate (I = 0.1873) and City Development Index (I = 0.0900). In addition, two indicators presented significant negative association with IHD mortality rate: Adjusted Population Size (I = −0.1216) and Gross Domestic Product (I = −0.0864). We also found a positive association between IHD mortality rates and the geographic distances between patients’ city of residence and their corresponding regional referral centers in interventional cardiology (I = 0.3368). Cities located within Regional Health Units with Reference Interventional Cardiology Center presented a significantly lower average specific mortality rate by IHD. The high mortality rate by IHD within the Regional Health Units was not restricted to socioeconomic and demographic variables, but dependent on the distance between each city and their reference interventional cardiology center. Conclusions We conclude that geographic factors play a significant role in IHD mortality within cities. These findings have important policy implications regarding the geographic

  3. Regional health accounts for Pakistan--expenditure disparities on provincial and district level.

    PubMed

    Lorenz, Christian; Khalid, Muhammad

    2011-05-01

    Since May 2009 the first National Health Accounts (NHA) for Pakistan have been finalised and published by Federal Bureau of Statistics (FBS) in cooperation with German Technical Cooperation (GTZ). This paper goes one step ahead of the report and analyses in more detail the regional differences in health expenditure structures in Pakistan. The further analyses can be divided into four parts: health expenditures in provinces (Provincial Health Accounts, PHA), Punjab provincial and district governments health expenditures and its comparison with ADB figures, all districts of Pakistan and comparison between total district government and provincial government expenditure for each province; the latter calculation is applied as indication for the degree of fiscal autonomy of the districts in each province. Consequently, first the provincial health expenditures by Financial Agents is analysed and compared between the provinces which leads to very heterogeneous results (section 2); the per capita health expenditures differ from 16 to 23 USD. Secondly, NHA results on Punjab district government are compared with available ADB results and differences in methods as possible reasons for different results are presented (section 3). Third, district data of all district governments in all four Pakistani provinces are analysed on the level of detailed function codes in section 4; the aim is to discover regional differences between districts of the same as well as of different provinces. Fourth, in section 5 the degree of fiscal autonomy on health of the districts in each province is analysed; therefore the ordinance description is reviewed and total district government with total provincial government expenditures are compared per province. Finally recommendations for future rounds of NHA in Pakistan are given regarding formats and necessities of detailed health expenditure data collection to ensure evidence based decision making not only on federal, but also on provincial and

  4. Factors affecting motivation and retention of primary health care workers in three disparate regions in Kenya.

    PubMed

    Ojakaa, David; Olango, Susan; Jarvis, Jordan

    2014-06-06

    The World Health Organization (WHO) and the Government of Kenya alike identify a well-performing health workforce as key to attaining better health. Nevertheless, the motivation and retention of health care workers (HCWs) persist as challenges. This study investigated factors influencing motivation and retention of HCWs at primary health care facilities in three different settings in Kenya - the remote area of Turkana, the relatively accessible region of Machakos, and the disadvantaged informal urban settlement of Kibera in Nairobi. A cross-sectional cluster sample design was used to select 59 health facilities that yielded interviews with 404 health care workers, grouped into 10 different types of service providers. Data were collected in November 2011 using structured questionnaires and a Focus Group Discussion guide. Findings were analyzed using bivariate and multivariate methods of the associations and determinants of health worker motivation and retention. The levels of education and gender factors were lowest in Turkana with female HCWs representing only 30% of the workers against a national average of 53%. A smaller proportion of HCWs in Turkana feel that they have adequate training for their jobs. Overall, 13% of the HCWs indicated that they had changed their job in the last 12 months and 20% indicated that they could leave their current job within the next two years. In terms of work environment, inadequate access to electricity, equipment, transport, housing, and the physical state of the health facility were cited as most critical, particularly in Turkana. The working environment is rated as better in private facilities. Adequate training, job security, salary, supervisor support, and manageable workload were identified as critical satisfaction factors. Family health care, salary, and terminal benefits were rated as important compensatory factors. There are distinct motivational and retention factors that affect HCWs in the three regions. Findings and

  5. Factors affecting motivation and retention of primary health care workers in three disparate regions in Kenya

    PubMed Central

    2014-01-01

    Background The World Health Organization (WHO) and the Government of Kenya alike identify a well-performing health workforce as key to attaining better health. Nevertheless, the motivation and retention of health care workers (HCWs) persist as challenges. This study investigated factors influencing motivation and retention of HCWs at primary health care facilities in three different settings in Kenya - the remote area of Turkana, the relatively accessible region of Machakos, and the disadvantaged informal urban settlement of Kibera in Nairobi. Methods A cross-sectional cluster sample design was used to select 59 health facilities that yielded interviews with 404 health care workers, grouped into 10 different types of service providers. Data were collected in November 2011 using structured questionnaires and a Focus Group Discussion guide. Findings were analyzed using bivariate and multivariate methods of the associations and determinants of health worker motivation and retention. Results The levels of education and gender factors were lowest in Turkana with female HCWs representing only 30% of the workers against a national average of 53%. A smaller proportion of HCWs in Turkana feel that they have adequate training for their jobs. Overall, 13% of the HCWs indicated that they had changed their job in the last 12 months and 20% indicated that they could leave their current job within the next two years. In terms of work environment, inadequate access to electricity, equipment, transport, housing, and the physical state of the health facility were cited as most critical, particularly in Turkana. The working environment is rated as better in private facilities. Adequate training, job security, salary, supervisor support, and manageable workload were identified as critical satisfaction factors. Family health care, salary, and terminal benefits were rated as important compensatory factors. Conclusions There are distinct motivational and retention factors that affect

  6. Disparity in regional and systemic circulatory capacities: do they affect the regulation of the circulation?

    PubMed Central

    Calbet, J. A. L.; Joyner, M. J.

    2010-01-01

    In this review we integrate ideas about regional and systemic circulatory capacities and the balance between skeletal muscle blood flow and cardiac output during heavy exercise in humans. In the first part of the review we discuss issues related to the pumping capacity of the heart and the vasodilator capacity of skeletal muscle. The issue is that skeletal muscle has a vast capacity to vasodilate during exercise [~300 mL (100 g)−1 min−1], but the pumping capacity of the human heart is limited to 20–25 L min−1 in untrained subjects and ~35 L min−1 in elite endurance athletes. This means that when more than 7–10 kg of muscle is active during heavy exercise, perfusion of the contracting muscles must be limited or mean arterial pressure will fall. In the second part of the review we emphasize that there is an interplay between sympathetic vasoconstriction and metabolic vasodilation that limits blood flow to contracting muscles to maintain mean arterial pressure. Vasoconstriction in larger vessels continues while constriction in smaller vessels is blunted permitting total muscle blood flow to be limited but distributed more optimally. This interplay between sympathetic constriction and metabolic dilation during heavy whole-body exercise is likely responsible for the very high levels of oxygen extraction seen in contracting skeletal muscle. It also explains why infusing vasodilators in the contracting muscles does not increase oxygen uptake in the muscle. Finally, when ~80% of cardiac output is directed towards contracting skeletal muscle modest vasoconstriction in the active muscles can evoke marked changes in arterial pressure. PMID:20345408

  7. Disparity in regional and systemic circulatory capacities: do they affect the regulation of the circulation?

    PubMed

    Calbet, J A L; Joyner, M J

    2010-08-01

    In this review we integrate ideas about regional and systemic circulatory capacities and the balance between skeletal muscle blood flow and cardiac output during heavy exercise in humans. In the first part of the review we discuss issues related to the pumping capacity of the heart and the vasodilator capacity of skeletal muscle. The issue is that skeletal muscle has a vast capacity to vasodilate during exercise [approximately 300 mL (100 g)(-1) min(-1)], but the pumping capacity of the human heart is limited to 20-25 L min(-1) in untrained subjects and approximately 35 L min(-1) in elite endurance athletes. This means that when more than 7-10 kg of muscle is active during heavy exercise, perfusion of the contracting muscles must be limited or mean arterial pressure will fall. In the second part of the review we emphasize that there is an interplay between sympathetic vasoconstriction and metabolic vasodilation that limits blood flow to contracting muscles to maintain mean arterial pressure. Vasoconstriction in larger vessels continues while constriction in smaller vessels is blunted permitting total muscle blood flow to be limited but distributed more optimally. This interplay between sympathetic constriction and metabolic dilation during heavy whole-body exercise is likely responsible for the very high levels of oxygen extraction seen in contracting skeletal muscle. It also explains why infusing vasodilators in the contracting muscles does not increase oxygen uptake in the muscle. Finally, when approximately 80% of cardiac output is directed towards contracting skeletal muscle modest vasoconstriction in the active muscles can evoke marked changes in arterial pressure.

  8. Mississippi communities for healthy living: implementing a nutrition intervention effectiveness study in a rural health disparate region

    USDA-ARS?s Scientific Manuscript database

    Intervention research in rural, health disparate communities presents unique challenges for study design, implementation, and evaluation. Challenges include: 1) culturally appropriate intervention components; 2) participant recruitment and retention; 3) treatment cross-contamination; 4) intervention...

  9. Radiocarbon dates of late quaternary mammals in the Archangelsk Region and their contribution to reconstructions of the last glaciation in Eastern Europe

    NASA Astrophysics Data System (ADS)

    Ponomarev, D. V.; Markova, A. K.; van Kolfschoten, T.; van der Plicht, J.

    2012-06-01

    Twelve new AMS (Accelerator Mass Spectrometry) dates of large Quaternary mammal remains were reported: mammoth ( Mammuthus primigenius, bison ( Bison priscus), and musk ox ( Ovibos pallantis) found in the Archangelsk Region. The absolute age of the identified samples varies from 46 000 to 22 000 calibrated years ago. These data suggest that a substantial part of the Archangelsk Region was not covered by ice during the indicated time interval.

  10. Radiocarbon chronology of woolly mammoth (Mammuthus primigenius) from Poland

    NASA Astrophysics Data System (ADS)

    Nadachowski, Adam; Lipecki, Grzegorz; Wojtal, Piotr

    2010-05-01

    Many fossil mammoth remains from more than 300 localities have been discovered over last 170 years in Poland. First radiocarbon dates of woolly mammoth from Poland were published in the 1960s and the 1970s. These dates must be regarded with caution due to absence of details of the used methods. Recently, about 40 fossil mammoth remains were radiocarbon dated by accelerator mass spectrometry (AMS) method in the Poznań Radiocarbon Laboratory. Dates are given as an uncalibrated radiocarbon dates (BP) and as calendar dates (cal. BP). The dates range from ca. 52 ka BP to ca. 13,2 ka BP (> 50,0 - ca. 16,1 cal. ka BP) and can be correlated with Oxygen Isotope Stage (OIS) 3 and OIS 2. A new radiocarbon evidence fits into the well known colonization pattern of Mammuthus primigenius in Central Europe and confirms a continuous distribution in the Grudziądz Interstadial (middle Weichselian, OIS 3) and the onset of the Last Glacial Maximum (LGM). On the other hand, the severe climatic circumstances lasting in conventional radiocarbon dates from ca. 22 ka BP to ca. 17 ka BP probably reduced the number of animals or even cased the withdrawal of woolly mammoth from the area north from the Sudetes and the Carpathian Mountains for 4-5 millennia. Only one date ca. 20,3 ka BP (ca. 24,2 cal, ka BP) is available from this time-span. Mammuthus primigenius reappeared in southern Poland ca. 14,6 ka BP (ca. 17,9 cal. BP) but soon had disappeared from this region because of marked reduction in open habitats at the beginning of Late Glacial Interglacial warming (Greenland Interstadial I or Bølling and Allerød) The latest available record from Poland is from Dzierżysław: 13,180±60 BP (ca. 15,600±400 cal. BP).

  11. Radiocarbon in the Weddell Sea as observed in a deep-sea coral and in krill

    SciTech Connect

    Michel, R.L.; Druffel, E.M.

    1983-03-01

    Radiocarbon mesurements were performed on krill and coral samples collected from the Weddell Sea during IWSOE '80. These are the first radiocarbon measurements available from this area since 1973. These data reveal carbon-14 levels for Weddell surface water and southern Weddell Shelf water. These data indicate that the radiocarbon levels in surface waters in 1980 were the same or slightly lower than those present in 1973. In addition, an unusually low ..delta../sup 14/C value for shelf water (from coral) at 500 m is evidence that Warm Deep Water (WDW) may penetrate much further and more frequently onto the shelf region than had previously been expected.

  12. Microscale radiocarbon dating of paintings

    NASA Astrophysics Data System (ADS)

    Hendriks, Laura; Hajdas, Irka; McIntyre, Cameron; Küffner, Markus; Scherrer, Nadim C.; Ferreira, Ester S. B.

    2016-03-01

    In this paper, radiocarbon dating of paintings using minimal sample sizes has been investigated, in an effort to address the problem of limited access to sample material in paintings. 14C analyses were conducted on signed and dated paintings from two Swiss artists of the twentieth century. The selected paintings dated from the 1930s and 1960s, provided the opportunity to evaluate the dating accuracy on paintings realized before and after 1950 AD when the 14C bomb peak was created, as a result of the nuclear tests conducted in the 1950/1960s. The work focused on the one hand on minimizing the size of the canvas sample required for accelerator mass spectrometer radiocarbon measurement on the gas ion source of the MICADAS and, on the other hand, on testing the possibility of dating the organic binder of the paint. Following careful characterization of the paint composition by X-ray fluorescence spectroscopy, Fourier transformed infrared spectroscopy, and Raman spectroscopy, paints containing no other carbon source than the natural organic binder were identified and dated.

  13. RADIOCARBON SOURCE APPORTIONMENT IN A BIOFUELS ERA

    EPA Science Inventory

    Biofuels (gasohol and biodiesel) introduce radiocarbon into the U.S. mobile source fuel supply where it was previously absent. Initial measurements of radiocarbon in the PM2.5 combustion emissions from engines using gasohol indicate that this may have less effect on r...

  14. Study on disparity of regional economic development based on geoinformatic Tupu and GWR model: a case of growth of GDP per capita in China from 1999 to 2003

    NASA Astrophysics Data System (ADS)

    Li, Feixue; Li, Manchun; Liang, Jian

    2007-06-01

    Regional disparity of economic development in China is always greatly concerned by investigators domestic and abroad, and sets of models have been used in the analysis. Spatial dependence, which is hidden in the data with spatial attributes, usually is not taken into account in classical statistics methods, such as ordinary linear regression(OLR) model. Along with the development of spatial statistics, more and more attentions are paid on spatial interactions between observations in the study of regional disparity. Geographically weighted regression (GWR) is a simple but effective model to recognize spatial variation and local difference, which considers the influence of the spatially non-stationarity of the variables. In this study, GWR model and Geo-Informatic Tupu were used to analyze the disparity of regional economic development in China, taking GDP per capita in 1999 and 2003 as a case, which is usually used to measure level of economic development. GDP per capita in the 338 cities in 1999 were selected to simulate GDP per capita in 2003 and to analysis non-stationarity of the growth of GDP per capita. Using Geo-Informatic Tupu, A series of maps were processed to display patterns of local parameter estimates, such as local r-squares, the residual sum of squares, local residual and so on, to gain a better understanding of the degree of spatial non-stationarity in a relationship over space. We tested for geographic heterogeneity in the parameters and compare them to estimates obtained from global regression approaches. The results suggested there was heterogeneity in the regression coefficients across broad regions of China, and a one-size fits all approach to describe growth processes appeared simplistic. The GWR model improved over the OLR model, and it was able to better explain the variation in the data and to simulate GDP per capita with smaller errors than the OLR models.

  15. Simultaneous detection of Entamoeba histolytica/dispar, Giardia duodenalis and cryptosporidia by immunochromatographic assay in stool samples from patients living in the Greater Cairo Region, Egypt.

    PubMed

    Banisch, Dagmar M; El-Badry, Ayman; Klinnert, Jorge V; Ignatius, Ralf; El-Dib, Nadia

    2015-08-01

    Gastrointestinal infection due to intestinal parasites is an enormous health problem in developing countries and its reliable diagnosis is demanding. Therefore, this study aimed at evaluating a commercially available immunochromatographic assay (ICA) for the detection of cryptosporidia, Giardia duodenalis, and Entamoeba histolytica/dispar for its usefulness in the Greater Cairo Region, Egypt. Stool samples of 104 patients who presented between October 2012 and March 2013 with gastrointestinal symptoms or for the exclusion of parasites at Kasr-Al-Ainy University Medical School were examined by light microscopy of wet mounts and the triple ICA. Microscopy revealed in 20% of the patients [95% confidence interval (CI), 13.5-29.0%] parasites with Hymenolepis nana, E. histolytica/dispar and Blastocystis hominis being the most frequent ones, but was not able to detect G. duodenalis and cryptosporidia, whereas ICA was positive in 21% (95% CI, 14.3-30.0%) and detected E. histolytica/dispar in 12.5% (95% CI, 7.3-20.4%), cryptosporidia in 6.7% (95% CI, 3.1-13.5%) and G. duodenalis in 15.4% (95% CI, 9.6-23.6%) of the patients. Detection of one or more pathogens was associated with access to water retrieved from a well or pump (p = 0.01). Patients between 20 and 29 years of age (p = 0.08) and patients with symptoms of 5 days or longer (p = 0.07) tended to have a higher risk to be infected than patients of other age groups or with shorter-lasting symptoms. In conclusion, the ICA was easy to perform and timesaving. Importantly, it enabled the detection of cryptosporidia, which cannot be found microscopically in unstained smears, demonstrated a higher sensitivity for the detection of G. duodenalis than microscopy, and was more specific for distinguishing E. histolytica/dispar from apathogenic amoeba.

  16. Radiocarbon dating of terrestrial carbonates

    USGS Publications Warehouse

    Pigati, Jeffrey S.; Rink, W. Jack; Thompson, Jeroen

    2014-01-01

    Terrestrial carbonates encompass a wide range of materials that potentially could be used for radiocarbon (14C) dating. Biogenic carbonates, including shells and tests of terrestrial and aquatic gastropods, bivalves, ostracodes, and foraminifera, are preserved in a variety of late Quaternary deposits and may be suitable for 14C dating. Primary calcareous deposits (marls, tufa, speleothems) and secondary carbonates (rhizoliths, fracture fill, soil carbonate) may also be targeted for dating when conditions are favorable. This chapter discusses issues that are commonly encountered in 14C dating of terrestrial carbonates, including isotopic disequilibrium and open-system behavior, as well as methods used to determine the reliability of ages derived from these materials. Recent methodological advancements that may improve the accuracy and precision of 14C ages of terrestrial carbonates are also highlighted.

  17. Towards a North Atlantic Marine Radiocarbon Calibration Curve

    NASA Astrophysics Data System (ADS)

    Austin, William; Reimer, Paula; Blaauw, Maarten; Bryant, Charlotte; Rae, James; Burke, Andrea

    2015-04-01

    Service du dejeuner! Twenty years ago, in 1995, I sailed as a post-doctoral researcher based at the University of Edinburgh (UK) on the first scientific mission of the new Marion Dufresne II. In this presentation, I will provide an update on the work that first quantified North Atlantic marine radiocarbon reservoir ages, highlighting how advances in marine tephrochronology over the last twenty years have significantly improved our understanding (and ability to test) land-ice-ocean linkages. The mechanistic link that connects marine radiocarbon reservoir ages to ocean ventilation state will also be discussed with reference to the Younger Dryas climate anomaly, where models and data have been successfully integrated. I will discuss the use of reference chronologies in the North Atlantic region and evaluate the common practice of climate synchronization between the Greenland ice cores and some of the key MD records that are now available. The exceptional quality of the MD giant piston cores and their potential to capture high-resolution last glacial sediment records from the North Atlantic provides an exciting opportunity to build new regional marine radiocarbon calibration curves. I will highlight new efforts by my co-authors and others to build such curves, setting-out a new agenda for the next twenty years of the IMAGES programme.

  18. New hydroxyproline radiocarbon dates from Sungir, Russia, confirm early Mid Upper Palaeolithic burials in Eurasia.

    PubMed

    Nalawade-Chavan, Shweta; McCullagh, James; Hedges, Robert

    2014-01-01

    Sungir (Russia) is a key Mid-Upper Palaeolithic site in Eurasia, containing several spectacular burials that disclose early evidence for complex burial rites in the form of a range of grave goods deposited along with the dead. Dating has been particularly challenging, with multiple radiocarbon dates ranging from 19,160±270 to 28,800±240 BP for burials that are believed to be closely similar in age. There are disparities in the radiocarbon dates of human bones, faunal remains and charcoal found on the floor of burials. Our approach has been to develop compound-specific methods using High Performance Liquid Chromatography (HPLC) to separate single amino acids, such as hydroxyproline, and thereby avoid the known human contamination on the bones themselves. Previously, we applied this technique to obtain radiocarbon dates of ∼30,000 BP for Sungir 2, Sungir 3 and a mammoth bone from the occupation levels of the site. The single amino acid radiocarbon dates were in good agreement with each other compared to all the dates previously reported, supporting their reliability. Here we report new hydroxyproline dates for two more human burials from the same site, Sungir 1 and Sungir 4. All five hydroxyproline dates reported are statistically indistinguishable and support an identical age for the group. The results suggest that compound-specific radiocarbon analysis should be considered seriously as the method of choice when precious archaeological remains are to be dated because they give a demonstrably contaminant-free radiocarbon age. The new ages are, together with the previously dated 'Red Lady of Paviland' human in the British Isles, the earliest for Mid Upper Palaeolithic burial behaviour in Eurasia, and point to the precocious appearance of this form of rite in Europe Russia.

  19. New Hydroxyproline Radiocarbon Dates from Sungir, Russia, Confirm Early Mid Upper Palaeolithic Burials in Eurasia

    PubMed Central

    Nalawade-Chavan, Shweta; McCullagh, James; Hedges, Robert

    2014-01-01

    Sungir (Russia) is a key Mid-Upper Palaeolithic site in Eurasia, containing several spectacular burials that disclose early evidence for complex burial rites in the form of a range of grave goods deposited along with the dead. Dating has been particularly challenging, with multiple radiocarbon dates ranging from 19,160±270 to 28,800±240 BP for burials that are believed to be closely similar in age. There are disparities in the radiocarbon dates of human bones, faunal remains and charcoal found on the floor of burials [1], [2], [3]. Our approach has been to develop compound-specific methods using High Performance Liquid Chromatography (HPLC) to separate single amino acids, such as hydroxyproline, and thereby avoid the known human contamination on the bones themselves. Previously, we applied this technique to obtain radiocarbon dates of ∼30,000 BP for Sungir 2, Sungir 3 and a mammoth bone from the occupation levels of the site [4]. The single amino acid radiocarbon dates were in good agreement with each other compared to all the dates previously reported, supporting their reliability. Here we report new hydroxyproline dates for two more human burials from the same site, Sungir 1 and Sungir 4. All five hydroxyproline dates reported are statistically indistinguishable and support an identical age for the group. The results suggest that compound-specific radiocarbon analysis should be considered seriously as the method of choice when precious archaeological remains are to be dated because they give a demonstrably contaminant-free radiocarbon age. The new ages are, together with the previously dated ‘Red Lady of Paviland’ human in the British Isles, the earliest for Mid Upper Palaeolithic burial behaviour in Eurasia, and point to the precocious appearance of this form of rite in Europe Russia. PMID:24416120

  20. Radiocarbon-based chronology for dynastic Egypt.

    PubMed

    Bronk Ramsey, Christopher; Dee, Michael W; Rowland, Joanne M; Higham, Thomas F G; Harris, Stephen A; Brock, Fiona; Quiles, Anita; Wild, Eva M; Marcus, Ezra S; Shortland, Andrew J

    2010-06-18

    The historical chronologies for dynastic Egypt are based on reign lengths inferred from written and archaeological evidence. These floating chronologies are linked to the absolute calendar by a few ancient astronomical observations, which remain a source of debate. We used 211 radiocarbon measurements made on samples from short-lived plants, together with a Bayesian model incorporating historical information on reign lengths, to produce a chronology for dynastic Egypt. A small offset (19 radiocarbon years older) in radiocarbon levels in the Nile Valley is probably a growing-season effect. Our radiocarbon data indicate that the New Kingdom started between 1570 and 1544 B.C.E., and the reign of Djoser in the Old Kingdom started between 2691 and 2625 B.C.E.; both cases are earlier than some previous historical estimates.

  1. Suicidal behaviour in Indigenous compared to non-Indigenous males in urban and regional Australia: Prevalence data suggest disparities increase across age groups.

    PubMed

    Armstrong, Gregory; Pirkis, Jane; Arabena, Kerry; Currier, Dianne; Spittal, Matthew J; Jorm, Anthony F

    2017-04-01

    We compare the prevalence of suicidal thoughts and attempts between Indigenous and non-Indigenous males in urban and regional Australia, and examine the extent to which any disparity between Indigenous and non-Indigenous males varies across age groups. We used data from the baseline wave of The Australian Longitudinal Study on Male Health (Ten to Men), a large-scale cohort study of Australian males aged 10-55 years residing in urban and regional areas. Indigenous identification was determined through participants self-reporting as Aboriginal, Torres Strait Islander or both. The survey collected data on suicidal thoughts in the preceding 2 weeks and lifetime suicide attempts. A total of 432 participants (2.7%) identified as Indigenous and 15,425 as non-Indigenous (97.3%). Indigenous males were twice as likely as non-Indigenous males to report recent suicidal thoughts (17.6% vs 9.4%; odds ratio = 2.1, p < 0.001) and more than three times as likely to report a suicide attempt in their lifetime (17.0% vs 5.1%; odds ratio = 3.6; p < 0.001). The prevalence of recent suicidal thoughts did not differ between Indigenous and non-Indigenous males in younger age groups, but a significant gap emerged among men aged 30-39 years and was largest among men aged 40-55 years. Similarly, the prevalence of lifetime suicide attempts did not differ between Indigenous and non-Indigenous males in the 14- to 17-years age group, but a disparity emerged in the 18- to 24-years age group and was even larger among males aged 25 years and older. Our paper presents unique data on suicidal thoughts and attempts among a broad age range of Indigenous and non-Indigenous males. The disparity in the prevalence of suicidal thoughts increased across age groups, which is in contrast to the large disparity between the Indigenous and non-Indigenous suicide rates in younger age groups.

  2. Health disparities among the western, central and eastern rural regions of China after a decade of health promotion and disease prevention programming.

    PubMed

    Zhang, Xi-Fan; Tian, Xiang-Yang; Cheng, Yu-Lan; Feng, Zhan-Chun; Wang, Liang; Southerland, Jodi

    2015-08-01

    Health disparities between the western, central and eastern regions of rural China, and the impact of national health improvement policies and programming were assessed. A total of 400 counties were randomly sampled. ANOVA and Logistic regression modeling were employed to estimate differences in health outcomes and determinants. Significant differences were found between the western, central and eastern rural regions in community infrastructure and health outcomes. From 2000 to 2010, health indicators in rural China were improved significantly, and the infant mortality rate (IMR), maternal mortality rate (MMR) and under 5 mortality rate (U5MR) had fallen by 62.79%, 71.74% and 61.92%, respectively. Central rural China had the greatest decrease in IMR (65.05%); whereas, western rural China had the greatest reduction in MMR (72.99%) but smallest reduction in U5MR (57.36%). Despite these improvements, Logistic regression analysis showed regional differences in key health outcome indicators (odds ratios): IMR (central: 2.13; western: 5.31), U5MR (central: 2.25; western: 5.69), MMR (central: 1.94; western: 3.31), and prevalence of infectious diseases (central: 1.62; western: 3.58). The community infrastructure and health outcomes of the western and central rural regions of China have been improved markedly during the first decade of the 21st century. However, health disparities still exist across the three regions. National efforts to increase per capita income, community empowerment and mobilization, community infrastructure, capacity of rural health facilities, and health literacy would be effective policy options to attain health equity.

  3. Disparities in Hypertension Prevalence, Awareness, Treatment and Control between Bouyei and Han: Results from a Bi-Ethnic Health Survey in Developing Regions from South China.

    PubMed

    Dong, Fen; Wang, Dingming; Pan, Li; Yu, Yangwen; Wang, Ke; Li, Ling; Wang, Li; Liu, Tao; Zeng, Xianjia; Sun, Liangxian; Zhu, Guangjin; Feng, Kui; Zhang, Biao; Xu, Ke; Pang, Xinglong; Chen, Ting; Pan, Hui; Ma, Jin; Zhong, Yong; Ping, Bo; Shan, Guangliang

    2016-02-19

    Hypertension is highly prevalent in low-income population. This study aims to investigate ethnic disparities in hypertension and identify modifiable factors related to its occurrence and control in developing regions in South China. Blood pressure was measured in the Bouyei and Han populations during a community-based health survey in Guizhou, 2012. A multistage stratified sampling method was adopted to recruit Bouyei and Han aged from 20 to 80 years. Taking mixed effects into consideration, multilevel logistic models with random intercept were used for data analysis. The prevalence rates of hypertension were 35.3% for the Bouyei and 33.7% for the Han. Among the hypertensive participants, 30.1% of the Bouyei and 40.2% of the Han were aware of their hypertensive conditions, 19.7% of the Bouyei and 31.1% of the Han were receiving treatment, and only 3.6% of the Bouyei and 9.9% of the Han had their blood pressure under control. Age-sex standardized rates of awareness, treatment, and control were consistently lower in the Bouyei than the Han. Such ethnic disparities were more evident in the elderly population. Avoidance of excessive alcohol consumption and better education were favorable lifestyle for reduction in risk of hypertension. Moderate physical activity improved control of hypertension in Bouyei patients under treatment. Conclusively, hypertension awareness, treatment, and control were substantially lower in Bouyei than Han, particularly in the elderly population. Such ethnic disparities indicate that elderly Bouyei population should be targeted for tailored interventions in the future.

  4. Disparities in Hypertension Prevalence, Awareness, Treatment and Control between Bouyei and Han: Results from a Bi-Ethnic Health Survey in Developing Regions from South China

    PubMed Central

    Dong, Fen; Wang, Dingming; Pan, Li; Yu, Yangwen; Wang, Ke; Li, Ling; Wang, Li; Liu, Tao; Zeng, Xianjia; Sun, Liangxian; Zhu, Guangjin; Feng, Kui; Zhang, Biao; Xu, Ke; Pang, Xinglong; Chen, Ting; Pan, Hui; Ma, Jin; Zhong, Yong; Ping, Bo; Shan, Guangliang

    2016-01-01

    Hypertension is highly prevalent in low-income population. This study aims to investigate ethnic disparities in hypertension and identify modifiable factors related to its occurrence and control in developing regions in South China. Blood pressure was measured in the Bouyei and Han populations during a community-based health survey in Guizhou, 2012. A multistage stratified sampling method was adopted to recruit Bouyei and Han aged from 20 to 80 years. Taking mixed effects into consideration, multilevel logistic models with random intercept were used for data analysis. The prevalence rates of hypertension were 35.3% for the Bouyei and 33.7% for the Han. Among the hypertensive participants, 30.1% of the Bouyei and 40.2% of the Han were aware of their hypertensive conditions, 19.7% of the Bouyei and 31.1% of the Han were receiving treatment, and only 3.6% of the Bouyei and 9.9% of the Han had their blood pressure under control. Age-sex standardized rates of awareness, treatment, and control were consistently lower in the Bouyei than the Han. Such ethnic disparities were more evident in the elderly population. Avoidance of excessive alcohol consumption and better education were favorable lifestyle for reduction in risk of hypertension. Moderate physical activity improved control of hypertension in Bouyei patients under treatment. Conclusively, hypertension awareness, treatment, and control were substantially lower in Bouyei than Han, particularly in the elderly population. Such ethnic disparities indicate that elderly Bouyei population should be targeted for tailored interventions in the future. PMID:26907309

  5. Late Holocene Radiocarbon Variability in Northwest Atlantic Slope Waters

    SciTech Connect

    Sherwood, O; Edinger, E; Guilderson, T P; Ghaleb, B; Risk, M J; Scott, D B

    2008-08-15

    Deep-sea gorgonian corals secrete a 2-part skeleton of calcite, derived from dissolved inorganic carbon at depth, and gorgonin, derived from recently fixed and exported particulate organic matter. Radiocarbon contents of the calcite and gorgonin provide direct measures of seawater radiocarbon at depth and in the overlying surface waters, respectively. Using specimens collected from Northwest Atlantic slope waters, we generated radiocarbon records for surface and upper intermediate water layers spanning the pre- and post bomb-{sup 14}C eras. In Labrador Slope Water (LSW), convective mixing homogenizes the pre-bomb {Delta}{sup 14}C signature (-67 {+-} 4{per_thousand}) to at least 1000 m depth. Surface water bomb-{sup 14}C signals were lagged and damped (peaking at {approx} +45{per_thousand} in the early 1980s) relative to other regions of the northwest Atlantic, and intermediate water signals were damped further. Off southwest Nova Scotia, the vertical gradient in {Delta}{sup 14}C is much stronger. In surface water, pre-bomb {Delta}{sup 14}C averaged -75 {+-} 5{per_thousand}. At 250-475 m depth, prebomb {Delta}{sup 14}C oscillated quasi-decadally between -80 and -100{per_thousand}, likely reflecting interannual variability in the presence of Labrador Slope Water vs. Warm Slope Water (WSW). Finally, subfossil corals reveal no systematic changes in vertical {Delta}{sup 14}C gradients over the last 1200 years.

  6. Gender disparity in distribution of the major hydrophilic region variants of hepatitis B virus genotype C according to hepatitis B e antigen serostatus.

    PubMed

    Lee, Seoung-Ae; Cho, Yoo-Kyung; Lee, Keun-Hwa; Hwang, Eung-Soo; Kook, Yoon-Hoh; Kim, Bum-Joon

    2011-03-01

    Hepatitis B virus (HBV) e antigen (HBeAg) seroconversion during chronic HBV infection is known to play an important role in disease progression and patient response to antiviral agents. The aim of the present study was to analyze gender disparity in distribution of major hydrophilic region (MHR) variants according to HBeAg serostatus. Prevalence of MHR variants from 68 Korean patients with chronic hepatitis (31 HBeAg-positive and 37 HBeAg-negative) was examined in terms of HBeAg serostatus and sex by direct sequencing analysis of the MHR. Gender disparity was observed in the distribution of MHR variants according to HBeAg serostatus. In male patients, the prevalence of MHR variants was significantly higher in HBeAg negative patients than in HBeAg positive patients [58.8% (10/17 patients) vs. 14.3% (3/21 patients), P=0.004]. However, the same was not true in female patients [55.0% (11/20 patients) vs. 60.0% (6/10 patients), P=1.000)]. In addition, 2 mutation types (L110I and G145A) related to HBeAg serostatus were found. In conclusion, HBeAg seroconversion in male chronic patients infected with genotype C could lead to mutations of MHR, major target to host immune response, which might in turn contribute to HBV persistence and immune evasion. Copyright © 2011 Wiley-Liss, Inc.

  7. Regional Disparity in Physical Resources in the Health Sector in Iran: A Comparison of Two Time Periods

    PubMed Central

    AKBARI SARI, Ali; REZAEI, Satar; HOMAIE RAD, Enayatollah; DEHGHANIAN, Nasim; CHAVEHPOUR, Yousef

    2015-01-01

    Background: One of the major health policy issues, in the both developed and developing countries, is the equality in the distribution of health resources. The aim of this study was to investigate the disparity in the distribution of health physical resources across the provinces of Iran in 2001 and 2011. Methods: This was a cross-sectional retrospective study which investigated inequality in the distribution of health physical resources by three indexes of Gini Coefficient, Gaswirth index and Index of Dissimilarity. The data on provinces were obtained from the yearbook statistics and Ministry of Health, and Medical Education. The Excel software was used to calculated indexes. Results: The finding showed the mean Gini Coefficient for all variables was 0.178 in 2001 and 0.158 in 2011. Besides, the mean Gaswirth index and index of dissimilarity were 11.5 and 1.5% in 2001 and 11 and 1.4% in 2011, respectively. Conclusion: There was slightly inequality in distribution of physical health resources in Iran. According to the results of three indexes, this study showed when Tehran province excluding from total sample, the inequality was decreased. PMID:26258098

  8. Bayesian analysis of radiocarbon chronologies: examples from the European Late-glacial

    NASA Astrophysics Data System (ADS)

    Blockley, S. P. E.; Lowe, J. J.; Walker, M. J. C.; Asioli, A.; Trincardi, F.; Coope, G. R.; Donahue, R. E.

    2004-02-01

    Although there are many Late-glacial (ca. 15 000-11 000 cal. yr BP) proxy climate records from northwest Europe, some analysed at a very high temporal resolution (decadal to century scale), attempts to establish time-stratigraphical correlations between sequences are constrained by problems of radiocarbon dating. In an attempt to overcome some of these difficulties, we have used a Bayesian approach to the analysis of radiocarbon chronologies for two Late-glacial sites in the British Isles and one in the Adriatic Sea. The palaeoclimatic records from the three sites were then compared with that from the GRIP Greenland ice-core. Although there are some apparent differences in the timing of climatic events during the early part of the Late-glacial (pre-14 000 cal. yr BP), the results suggest that regional climatic changes appear to have been broadly comparable between Greenland, the British Isles and the Adriatic during the major part of the Late-glacial (i.e. between 14 000 and 11 000 cal. yr BP). The advantage of using the Bayesian approach is that it provides a means of testing the reliability of Late-glacial radiocarbon chronologies that is independent of regional chronostratigraphical (climatostratigraphical) frameworks. It also uses the full radiocarbon inventory available for each sequence and makes explicit any data selection applied. Potentially, therefore, it offers a more objective basis for comparing regional radiocarbon chronologies than the conventional approaches that have been used hitherto. Copyright

  9. Regional disparities in botulinum toxin A (BoNT-A) therapy for spasticity in Sweden: budgetary consequences of closing the estimated treatment gap.

    PubMed

    Ertzgaard, P; Anhammer, M; Forsmark, A

    2017-03-01

    As no national treatment guidelines for spasticity have been issued in Sweden, different regional treatment practices may potentially occur. This study examines botulinum toxin A (BoNT-A) treatment for spasticity on a regional level in Sweden and presents budgetary consequences of closing the estimated treatment gap. Prevalence of spasticity in Sweden was estimated from published data. Regional sales data for BoNT-A were acquired from IMS Health. A set proportion of hospital BoNT-A use was assumed to represent treatment of spasticity. Total intervention cost of BoNT-A treatment was gathered from healthcare regional tariffs, while costs associated with spasticity were derived from publications on multiple sclerosis and stroke. Results show that the regional variation in treatment of spasticity with BoNT-A is large, with approximately every fourth patient being treated in Southern healthcare region compared to every tenth in the Stockholm-Gotland or Western healthcare regions. The incremental cost of filling the reported treatment gap was also assessed and was estimated at around 9.4 million EUR. However, for the incremental cost to be offset by savings in spasticity-related costs, only a small proportion of treatment responders (defined as patients transitioning to a lower severity grade of spasticity) was required (12%). The study revealed apparent regional disparities of BoNT-A treatment for spasticity in Sweden. The results further suggest that the incremental cost of eliminating the treatment gap has a high probability of being offset by savings in direct costs, even at a low proportion of the patients reaching clinical improvement. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Characterization of Non-Nutritive Sweetener Intake in Rural Southwest Virginian Adults Living in a Health-Disparate Region

    PubMed Central

    Passaro, Erin M.; Davy, Brenda M.; You, Wen; Zoellner, Jamie M.

    2017-01-01

    Few data assessing non-nutritive sweetener (NNS) intake are available, especially within rural, health-disparate populations, where obesity and related co-morbidities are prevalent. The objective of this study is to characterize NNS intake for this population and examine the variance in demographics, cardio-metabolic outcomes, and dietary intake between NNS consumers and non-consumers. A cross-sectional sample (n = 301) of Virginian adults from a randomized controlled trial (data collected from 2012 to 2014) targeting sugar-sweetened beverage (SSB) intake completed three 24-h dietary recalls, and demographics and cardio-metabolic measures were assessed. The frequency, types, and sources of NNS consumption were identified. Thirty-three percent of participants reported consuming NNS (n = 100). Sucralose was the largest contributor of mean daily NNS intake by weight (mg), followed by aspartame, acesulfame potassium, and saccharin. NNS in tabletop sweeteners, diet tea, and diet soda were the top contributors to absolute NNS intake. The most frequently consumed NNS sources were diet sodas, juice drinks, and tabletop sweeteners. Although mean body mass index (BMI) was greater for NNS consumers, they demonstrated significantly lower food, beverage, and SSB caloric intake and energy density, and higher overall dietary quality. It remains unclear whether NNS use plays a role in exacerbating weight gain. NNS consumers in this sample may have switched from drinking predominantly SSB to drinking some NNS beverages in an effort to cope with weight gain. Future studies should explore motivations for NNS use across a variety of weight and health categories. PMID:28708096

  11. Low energy cyclotron for radiocarbon dating

    SciTech Connect

    Welch, J.J.

    1985-01-01

    The author built and tested a low energy cyclotron for radiocarbon dating similar to a conventional mass spectrometer. These tests clearly show that with the addition of a conventional ion source, the low energy cyclotron can perform the extremely high sensitivity /sup 14/C measurements that are now done at accelerator facilities. The author found that no significant background is present when the cyclotron is tuned to accelerate /sup 14/C negative ions and the transmission efficiency is adequate to perform radiocarbon dating on milligram samples of carbon. The internal ion source used did not produce sufficient current to detect /sup 14/C directly at modern concentrations. The author shows how a conventional carbon negative ion source located outside the cyclotron magnet, would produce sufficient beam and provide for quick sample changing to make radiocarbon dating milligram samples with a modest laboratory instrument feasible.

  12. a Radiocarbon Database for Improved Understanding of Global Soil Carbon Dynamics: Part II

    NASA Astrophysics Data System (ADS)

    Trumbore, S.; Torn, M. S.; Sierra, C. A.; Smith, L. J.; Nave, L. E.; Workshop Paritipants, R.

    2011-12-01

    We report results of a workshop to initiate a global database of radiocarbon measurements in soil and other ecosystem compartments. Radiocarbon provides critical information for understanding the rate of exchange of soil carbon with the atmosphere and hydrosphere. For example, radiocarbon has been used to demonstrate the importance of short range order minerals in stabilizing organic carbon on millennial timescales in some soils. On decadal to centennial timescales, the infiltration of 'bomb' radiocarbon provides a measure of the amount and nature of soil carbon that responds on the timescale of most human impacts. The radiocarbon sigature of chemically or physically fractionated soil, or even in specific organic compounds, can yield clues as to controls on organic matter cycling on a range of timescales. Radiocarbon in microbial biomass or respiration can be a sensitive indicator of shifts in substrate use with vegetation, nutrient availability or temperature change. Taken toghether, such measurements can provide critical tests for models of soil carbon dynamics, while patterns in soil C dynamics with edaphic factors can be used to help parameterize models at spatial scales ranging from profile to landscape to global. The advent and proliferation of accelerator mass spectrometry since the early 1990s has vastly increased the number of radiocarbon analyses carried out in soils. However, these studies have usually been carried out by individual investigators within specific sites or regions, and to date the results have not been assembled, interpreted or compared at larger spatial scales. Given the expense of radiocarbon measurements, and the need for global synthesis products to evaluate and/or develop models of soil carbon response to climate and land use changes across a range of spatial scales, our goals are to: (1) bring together in one place existing radiocarbon measurements and provide a continuing common repository for new analyses; (2) supply ancillary

  13. Can UK fossil fuel emissions be determined by radiocarbon measurements?

    NASA Astrophysics Data System (ADS)

    Wenger, Angelina; O'Doherty, Simon; Rigby, Matthew; Manning, Alistair; Palmer, Paul

    2016-04-01

    The GAUGE project evaluates different methods to estimate UK emissions. However, estimating carbon dioxide emissions as a result of fossil fuel burning is challenging as natural fluxes in and out of the atmosphere are very large. Radiocarbon (14C) measurements offer a way to specifically measure the amount of recently added carbon dioxide from fossil fuel burning. This is possible as, due to their age, all the radiocarbon in fossil fuels has decayed. Hence the amount of recently added CO2 from fossil fuel burning can be measured as a depletion of the 14C content in air. While this method has been successfully applied by several groups on a city or a regional scale, this is the first attempt at using the technique for a national emission estimate. Geographically the UK, being an island, is a good location for such an experiment. But are 14CO2 measurements the ideal solution for estimating fossil fuel emissions as they are heralded to be? Previous studies have shown that 14CO2emissions from the nuclear industry mask the 14C depletion caused by fossil fuel burning and result in an underestimation of the fossil fuel CO2. While this might not be a problem in certain regions around the world, many countries like the UK have a substantial nuclear industry. A correction for this enhancement from the nuclear industry can be applied but are invariably difficult as 14CO2emissions from nuclear power plants have a high temporal variability. We will explain how our sampling strategy was chosen to minimize the influence form the nuclear industry and why this proved to be challenging. In addition we present the results from our ground based measurements to show why trying to estimate national emissions using radiocarbon measurements was overambitious, and how practical the technique is for the UK in general.

  14. An Illustrated Guide to Measuring Radiocarbon from Archaeological Samples

    ERIC Educational Resources Information Center

    Bayliss, Alex; McCormac, Gerry; van der Plicht, Hans

    2004-01-01

    Radiocarbon dating has been central to the construction of archaeological chronologies for over 50 years. The archaeological, scientific and (increasingly) statistical methods for interpreting radiocarbon measurements to produce these chronologies have become ever more sophisticated. The accurate measurement of the radiocarbon content of an…

  15. An Illustrated Guide to Measuring Radiocarbon from Archaeological Samples

    ERIC Educational Resources Information Center

    Bayliss, Alex; McCormac, Gerry; van der Plicht, Hans

    2004-01-01

    Radiocarbon dating has been central to the construction of archaeological chronologies for over 50 years. The archaeological, scientific and (increasingly) statistical methods for interpreting radiocarbon measurements to produce these chronologies have become ever more sophisticated. The accurate measurement of the radiocarbon content of an…

  16. Spatial disparities of regional forest land change based on ESDA and GIS at the county level in Beijing-Tianjin-Hebei area

    NASA Astrophysics Data System (ADS)

    Xie, Hualin; Kung, Chih-Chun; Zhao, Yuluan

    2012-12-01

    Forest land is the essential and important natural resource that provides strong support for human survival and development. Research on forest land changes at the county level about its characteristics, rules, and spatial patterns is, therefore, important for regional resource protection and the sustainable development of the social economy. In this study we selected the GIS and Geoda software package to explore the spatial disparities of forest land changes at the Beijing-Tianjin-Hebei area county level, based on the global and local spatial autocorrelation analyses of exploratory spatial data. The results show that: 1) during 1985-2000, the global spatial autocorrelation of forest land change is significant in the study area. The global Moran's I value is 0.3122 for the entire time period and indicates significant positive spatial correlation ( p < 0.05). Moran's I value of forest land change decreases from 0.3084 at the time stage I to 0.3024 at the time stage II; 2) the spatial clustering characteristics of forest land changes appear on the whole in Beijing-Tianjin-Hebei area. Moran's I value decreases from the time stage I to time stage II, which means that trend of spatial clustering of forest land change is weakened in the Beijing-Tianjin-Hebei area; 3) the grid map of the local Moran's I for each county reflects local spatial homogeneity of forest land change, which means that spatial clustering about regions of high value and low value is especially significant. The regions with "High-High" correlation are mainly located in the north hilly area. However, the regions with "Low-Low" correlation were distributed in the middle of the study area. Therefore, protection strategies and concrete measures should be put in place for each regional cluster in the study area.

  17. Does availability of physical activity and food outlets differ by race and income? Findings from an enumeration study in a health disparate region.

    PubMed

    Hill, Jennie L; Chau, Clarice; Luebbering, Candice R; Kolivras, Korine K; Zoellner, Jamie

    2012-09-06

    Low-income, ethnic/racial minorities and rural populations are at increased risk for obesity and related chronic health conditions when compared to white, urban and higher-socio-economic status (SES) peers. Recent systematic reviews highlight the influence of the built environment on obesity, yet very few of these studies consider rural areas or populations. Utilizing a CBPR process, this study advances community-driven causal models to address obesity by exploring the difference in resources for physical activity and food outlets by block group race and income in a small regional city that anchors a rural health disparate region. To guide this inquiry we hypothesized that lower income and racially diverse block groups would have fewer food outlets, including fewer grocery stores and fewer physical activity outlets. We further hypothesized that walkability, as defined by a computed walkability index, would be lower in the lower income block groups. Using census data and GIS, base maps of the region were created and block groups categorized by income and race. All food outlets and physical activity resources were enumerated and geocoded and a walkability index computed. Analyses included one-way MANOVA and spatial autocorrelation. In total, 49 stores, 160 restaurants and 79 physical activity outlets were enumerated. There were no differences in the number of outlets by block group income or race. Further, spatial analyses suggest that the distribution of outlets is dispersed across all block groups. Under the larger CPBR process, this enumeration study advances the causal models set forth by the community members to address obesity by providing an overview of the food and physical activity environment in this region. This data reflects the food and physical activity resources available to residents in the region and will aid many of the community-academic partners as they pursue intervention strategies targeting obesity.

  18. Does availability of physical activity and food outlets differ by race and income? Findings from an enumeration study in a health disparate region

    PubMed Central

    2012-01-01

    Background Low-income, ethnic/racial minorities and rural populations are at increased risk for obesity and related chronic health conditions when compared to white, urban and higher-socio-economic status (SES) peers. Recent systematic reviews highlight the influence of the built environment on obesity, yet very few of these studies consider rural areas or populations. Utilizing a CBPR process, this study advances community-driven causal models to address obesity by exploring the difference in resources for physical activity and food outlets by block group race and income in a small regional city that anchors a rural health disparate region. To guide this inquiry we hypothesized that lower income and racially diverse block groups would have fewer food outlets, including fewer grocery stores and fewer physical activity outlets. We further hypothesized that walkability, as defined by a computed walkability index, would be lower in the lower income block groups. Methods Using census data and GIS, base maps of the region were created and block groups categorized by income and race. All food outlets and physical activity resources were enumerated and geocoded and a walkability index computed. Analyses included one-way MANOVA and spatial autocorrelation. Results In total, 49 stores, 160 restaurants and 79 physical activity outlets were enumerated. There were no differences in the number of outlets by block group income or race. Further, spatial analyses suggest that the distribution of outlets is dispersed across all block groups. Conclusions Under the larger CPBR process, this enumeration study advances the causal models set forth by the community members to address obesity by providing an overview of the food and physical activity environment in this region. This data reflects the food and physical activity resources available to residents in the region and will aid many of the community-academic partners as they pursue intervention strategies targeting obesity. PMID

  19. Radiocarbon dating of ancient rock paintings.

    PubMed

    Rowe, Marvin W

    2009-03-01

    A technique based on cold argon and oxygen plasmas permits radiocarbon dates to be obtained on paintings that contain inorganic pigments. (To listen to a podcast about this feature, please go to the Analytical Chemistry website at http://pubs.acs.org/journal/ancham.).

  20. Lack of Healthy Food Options on Children’s Menus of Restaurants in the Health-Disparate Dan River Region of Virginia and North Carolina, 2013

    PubMed Central

    Olive, Nicole C.; Waters, Clarice N.; Estabrooks, Paul A.; You, Wen; Zoellner, Jamie M.

    2015-01-01

    Introduction Interest has increased in understanding the types and healthfulness of restaurant foods for children, particularly in disadvantaged areas. The purpose of this community-based participatory research study was to describe the quality of restaurant food offered to children in a health-disparate region in Virginia and North Carolina and to determine if the availability of healthy foods differed by location (rural, urban) or by the predominant race (black, white, mixed race) of an area’s population. Methods Restaurants offering a children’s menu in the 3 counties in Virginia and North Carolina that make up the Dan River Region were identified by using state health department records. Research assistants reviewed menus using the Children’s Menu Assessment (CMA), a tool consisting of 29 scored items (possible score range, −4 to 21). Scores were calculated for each restaurant. We obtained information on the predominant race of the population at the block group level for all counties from 2010 US Census data. Results For the 137 restaurants studied, mean CMA scores were low (mean, 1.6; standard deviation [SD], 2.7), ranging from −4 to 9 of 21 possible points. Scores were lowest for restaurants in the predominantly black block groups (mean, 0.2; SD, 0.4) and significantly different from the scores for restaurants in the predominantly white (mean, 1.4; SD, 1.6) and mixed-race block groups (mean, 2.6; SD, 2.4) (F = 4.3; P < .05). Conclusion Children’s menus available in the Dan River Region lack healthy food options, particularly in predominantly black block groups. These study findings can contribute to regional efforts in policy development or environmental interventions for children’s food quality by the community-based participatory research partnership and help local stakeholders to determine possible strategies and solutions for improving local food options for children. PMID:25811495

  1. Lack of healthy food options on children's menus of restaurants in the health-disparate Dan River region of Virginia and North Carolina, 2013.

    PubMed

    Hill, Jennie L; Olive, Nicole C; Waters, Clarice N; Estabrooks, Paul A; You, Wen; Zoellner, Jamie M

    2015-03-26

    Interest has increased in understanding the types and healthfulness of restaurant foods for children, particularly in disadvantaged areas. The purpose of this community-based participatory research study was to describe the quality of restaurant food offered to children in a health-disparate region in Virginia and North Carolina and to determine if the availability of healthy foods differed by location (rural, urban) or by the predominant race (black, white, mixed race) of an area's population. Restaurants offering a children's menu in the 3 counties in Virginia and North Carolina that make up the Dan River Region were identified by using state health department records. Research assistants reviewed menus using the Children's Menu Assessment (CMA), a tool consisting of 29 scored items (possible score range, -4 to 21). Scores were calculated for each restaurant. We obtained information on the predominant race of the population at the block group level for all counties from 2010 US Census data. For the 137 restaurants studied, mean CMA scores were low (mean, 1.6; standard deviation [SD], 2.7), ranging from -4 to 9 of 21 possible points. Scores were lowest for restaurants in the predominantly black block groups (mean, 0.2; SD, 0.4) and significantly different from the scores for restaurants in the predominantly white (mean, 1.4; SD, 1.6) and mixed-race block groups (mean, 2.6; SD, 2.4) (F = 4.3; P < .05). Children's menus available in the Dan River Region lack healthy food options, particularly in predominantly black block groups. These study findings can contribute to regional efforts in policy development or environmental interventions for children's food quality by the community-based participatory research partnership and help local stakeholders to determine possible strategies and solutions for improving local food options for children.

  2. Radiocarbon AMS at IOP: System improvements and dating of groundwater from Bhadrak district, Orissa

    NASA Astrophysics Data System (ADS)

    Prasad, G. V. Ravi; Dutta, K.; Ray, D. K.

    2008-04-01

    The radiocarbon AMS facility at Institute of Physics, Bhubaneswar is based on a 3 MV tandem accelerator. In this paper, we present the recent improvements to the AMS system at this general purpose accelerator facility. We report an effective method of overcoming terminal voltage instability often met with in switching between AMS and other modes of operation of the accelerator. We report the radiocarbon measurements made on connate groundwater samples from the Bhadrak district of Orissa state (eastern India) to identify the regions that require artificial recharge.

  3. Demographic and regional disparities in insulin pump utilization in a setting of universal funding: a New Zealand nationwide study.

    PubMed

    McKergow, Erin; Parkin, Lianne; Barson, David J; Sharples, Katrina J; Wheeler, Benjamin J

    2017-01-01

    Insulin pumps have been publically funded in New Zealand since 2012 for patients who meet certain clinical criteria; however, the patterns of utilization have not been described. We undertook a nationwide study to estimate the annual proportions of patients with type 1 diabetes mellitus who used a pump between 2012 and 2014, overall, and according to sex, age, ethnicity, socioeconomic position, and region. We used data from the New Zealand Virtual Diabetes Register and routinely collected national demographic, health, and pharmaceutical dispensing data from the Ministry of Health to identify patients with type 1 diabetes and to calculate the overall, and subgroup, proportions using pumps. Between 2012 and 2014, funded pump use among patients with type 1 diabetes (n = 13,727) increased from 1.8 to 9.3 % overall; however, there were differences in uptake according to demographic characteristics and region. In 2014, proportionate pump use was significantly higher in females versus males (adjusted odds ratio (OR) 2.0 [95 % confidence interval 1.8-2.3]), in those aged <20 years, and in some regions. Māori (indigenous people), Pacific, and Asian patients were significantly less likely to use pumps than New Zealand Europeans (ORs 0.30 [0.23-0.41], 0.26 [0.14-0.46], 0.22 [0.14-0.35], respectively), as were those in the most versus the least deprived socioeconomic decile (OR 0.36 [0.25-0.52]). It is essential to explore the factors driving differential insulin pump uptake, in both New Zealand and elsewhere, if all patients are to have equal opportunity to benefit from intensive diabetes management.

  4. Radiocarbon age of waters in the deep Atlantic revisited

    SciTech Connect

    Broecker, W.S.; Virgilio, A. ); Peng, T.H. )

    1991-01-01

    The authors use a simple box model to evaluate the impact of temporal changes of the atmosphere's {sup 14}C/C on ventilation fluxes for the deep Atlantic calculated from radiocarbon measurements. The conclusion is that despite the fact that over the 300 year period from 1650 to 1950 the atmosphere's radiocarbon content declined at the same rate as radiocarbon decays, this temporal change has a relatively small impact (10-15%) on radiocarbon-based estimates of the ventilation rate of the deep Atlantic. The reason is that the radiocarbon content of the source waters for deep Atlantic are reasonably well buffered against changes in atmospheric {sup 14}C/C.

  5. Rate of new HIV diagnoses among Latinos living in Florida: disparities by country/region of birth.

    PubMed

    Sheehan, Diana M; Trepka, Mary Jo; Fennie, Kristopher P; Maddox, Lorene M

    2015-01-01

    HIV incidence in the USA is three times higher for Latinos than for non-Latino whites. Latinos differ in educational attainment, poverty, insurance coverage, and health-care access, factors that affect HIV knowledge, risk behaviors, and testing. The purpose of this study was to identify differences in demographics, risk factors, and rate of new HIV diagnoses by birth country/region among Latinos in Florida to guide the targeting of primary and secondary prevention programs. Using Florida HIV/AIDS surveillance data from 2007 to 2011 and the American Community Survey, we compared demographic and risk factors, and calculated annual and five-year age-adjusted rates of new HIV diagnoses for 5801 Latinos by birth country/region. Compared to US-born Latinos, those born in Cuba and South America were significantly more likely to report the HIV transmission mode of MSM; those born in the Dominican Republic (DR) heterosexual transmission; and those born in Puerto Rico injection drug use. Mexican- and Central American-born Latinos were more likely to be diagnosed with AIDS within a month of HIV diagnosis. The rate of new HIV diagnoses among Latinos declined 33% from 2007 to 2011. HIV diagnoses over time decreased significantly for Latinos born in Mexico and increased nonsignificantly for those born in the DR. Although this study was limited to Latinos living in Florida, results suggest that tailoring HIV primary prevention and testing initiatives to specific Latino groups may be warranted.

  6. Sex disparities in risk and risk factors for ischemic heart disease in the Asia-Pacific region.

    PubMed

    Peters, Sanne Ae; Woodward, Mark; Lam, Tai H; Fang, Xianghua; Suh, Il; Ueshema, Hirotsugu; Dobson, Annette J; Grobbee, Diederick E; Huxley, Rachel R

    2014-05-01

    Ischemic heart disease (IHD) is the leading cause of death and disability worldwide, with higher rates among men than women. Relatively few studies on risk factor associations are available from the Asia-Pacific region, especially with regard to sex differences. Our objective was to compare the relationships between modifiable risk factors and IHD in men and women from the Asia-Pacific region. Data from 600,445 individuals from 44 studies from the Asia Pacific Cohort Studies Collaboration, an individual patient data overview, were used. Cox models were used to evaluate the effects of risk factors on fatal and non-fatal IHD separately in men and women from Australia and New Zealand (ANZ) and Asia. Over a median follow-up of 6.7 years, 5695 IHD events were documented. The hazard ratio for IHD, comparing men with women, was 2.14 (95% CI 1.97-2.33) in ANZ and 1.88 (95% CI 1.54-2.29) in Asia. The age-adjusted prevalence of major risk factors was generally higher in men than women, especially in ANZ. Risk factors acted broadly similarly between men and women in both Asia and ANZ, with any indications of differences tending to favor men, rather than women. The excess risk of IHD observed in men compared with women in both Asia and ANZ may be, at least in part, a result of a more hazardous risk profile in men compared with women. The contribution of sex differences in the magnitude of the risk factor-disease associations is unlikely to be a contributing factor.

  7. A complete terrestrial radiocarbon record for 11.2 to 52.8 kyr B.P.

    PubMed

    Bronk Ramsey, Christopher; Staff, Richard A; Bryant, Charlotte L; Brock, Fiona; Kitagawa, Hiroyuki; van der Plicht, Johannes; Schlolaut, Gordon; Marshall, Michael H; Brauer, Achim; Lamb, Henry F; Payne, Rebecca L; Tarasov, Pavel E; Haraguchi, Tsuyoshi; Gotanda, Katsuya; Yonenobu, Hitoshi; Yokoyama, Yusuke; Tada, Ryuji; Nakagawa, Takeshi

    2012-10-19

    Radiocarbon ((14)C) provides a way to date material that contains carbon with an age up to ~50,000 years and is also an important tracer of the global carbon cycle. However, the lack of a comprehensive record reflecting atmospheric (14)C prior to 12.5 thousand years before the present (kyr B.P.) has limited the application of radiocarbon dating of samples from the Last Glacial period. Here, we report (14)C results from Lake Suigetsu, Japan (35°35'N, 135°53'E), which provide a comprehensive record of terrestrial radiocarbon to the present limit of the (14)C method. The time scale we present in this work allows direct comparison of Lake Suigetsu paleoclimatic data with other terrestrial climatic records and gives information on the connection between global atmospheric and regional marine radiocarbon levels.

  8. Calibration of radiocarbon dates: tables based on the consensus data of the workshop on calibrating the radiocarbon time scale

    SciTech Connect

    Klein, J.; Lerman, J.C.; Damon, P.E.; Ralph, E.K.

    1982-01-01

    A calibration is presented for conventional radiocarbon ages ranging from 10 to 7240 years BP and thus covering a calendric range of 8000 years from 6050 BC to AD 1950. Distinctive features of this calibration include: (1) an improved data set consisting of 1154 radiocarbon measurements on samples of known age, (2) an extended range over which radiocarbon ages may be calibrated (an additional 530 years), (3) separate 95% confidence intervals (in tubular form) for six different radiocarbon uncertainties (20, 50, 100, 150, 200, 300 years), and (4) an estimate of the non-Poisson errors related to radiocarbon determinations, including an estimate of the systematic errors between laboratories.

  9. Radiocarbon dating casts doubt on the late chronology of the Middle to Upper Palaeolithic transition in southern Iberia.

    PubMed

    Wood, Rachel E; Barroso-Ruíz, Cecilio; Caparrós, Miguel; Jordá Pardo, Jesús F; Galván Santos, Bertila; Higham, Thomas F G

    2013-02-19

    It is commonly accepted that some of the latest dates for Neanderthal fossils and Mousterian industries are found south of the Ebro valley in Iberia at ca. 36 ka calBP (calibrated radiocarbon date ranges). In contrast, to the north of the valley the Mousterian disappears shortly before the Proto-Aurignacian appears at ca. 42 ka calBP. The latter is most likely produced by anatomically modern humans. However, two-thirds of dates from the south are radiocarbon dates, a technique that is particularly sensitive to carbon contaminants of a younger age that can be difficult to remove using routine pretreatment protocols. We have attempted to test the reliability of chronologies of 11 southern Iberian Middle and early Upper Paleolithic sites. Only two, Jarama VI and Zafarraya, were found to contain material that could be reliably dated. In both sites, Middle Paleolithic contexts were previously dated by radiocarbon to less than 42 ka calBP. Using ultrafiltration to purify faunal bone collagen before radiocarbon dating, we obtain ages at least 10 ka (14)C years older, close to or beyond the limit of the radiocarbon method for the Mousterian at Jarama VI and Neanderthal fossils at Zafarraya. Unless rigorous pretreatment protocols have been used, radiocarbon dates should be assumed to be inaccurate until proven otherwise in this region. Evidence for the late survival of Neanderthals in southern Iberia is limited to one possible site, Cueva Antón, and alternative models of human occupation of the region should be considered.

  10. Marine04 Marine radiocarbon age calibration, 26 ? 0 ka BP

    SciTech Connect

    Hughen, K; Baille, M; Bard, E; Beck, J; Bertrand, C; Blackwell, P; Buck, C; Burr, G; Cutler, K; Damon, P; Edwards, R; Fairbanks, R; Friedrich, M; Guilderson, T; Kromer, B; McCormac, F; Manning, S; Bronk-Ramsey, C; Reimer, P; Reimer, R; Remmele, S; Southon, J; Stuiver, M; Talamo, S; Taylor, F; der Plicht, J v; Weyhenmeyer, C

    2004-11-01

    New radiocarbon calibration curves, IntCal04 and Marine04, have been constructed and internationally ratified to replace the terrestrial and marine components of IntCal98. The new calibration datasets extend an additional 2000 years, from 0-26 ka cal BP (Before Present, 0 cal BP = AD 1950), and provide much higher resolution, greater precision and more detailed structure than IntCal98. For the Marine04 curve, dendrochronologically dated tree-ring samples, converted with a box-diffusion model to marine mixed-layer ages, cover the period from 0-10.5 ka cal BP. Beyond 10.5 ka cal BP, high-resolution marine data become available from foraminifera in varved sediments and U/Th-dated corals. The marine records are corrected with site-specific {sup 14}C reservoir age information to provide a single global marine mixed-layer calibration from 10.5-26.0 ka cal BP. A substantial enhancement relative to IntCal98 is the introduction of a random walk model, which takes into account the uncertainty in both the calendar age and the radiocarbon age to calculate the underlying calibration curve. The marine datasets and calibration curve for marine samples from the surface mixed layer (Marine04) are discussed here. The tree-ring datasets, sources of uncertainty, and regional offsets are presented in detail in a companion paper by Reimer et al.

  11. A new small accelerator for radiocarbon dating

    SciTech Connect

    Suter, M.; Huber, R.; Jacob, S. A. W.; Synal, H.-A.; Schroeder, J. B.

    1999-06-10

    A new small and compact radiocarbon dating facility based on a 500 kV Pelletron accelerator has been built. The novel feature is that it operates with 1{sup +} ions. The interfering molecules are destroyed by collisions in the gas stripper. The results of first test measurements demonstrate that stability, background and transmission are equal to the performance of conventional AMS systems based on larger accelerators.

  12. Low energy cyclotron for radiocarbon dating

    SciTech Connect

    Welch, J.J.

    1984-12-01

    The measurement of naturally occurring radioisotopes whose half lives are less than a few hundred million years but more than a few years provides information about the temporal behavior of geologic and climatic processes, the temporal history of meteoritic bodies as well as the production mechanisms of these radioisotopes. A new extremely sensitive technique for measuring these radioisotopes at tandem Van de Graaff and cyclotron facilities has been very successful though the high cost and limited availability have been discouraging. We have built and tested a low energy cyclotron for radiocarbon dating similar in size to a conventional mass spectrometer. These tests clearly show that with the addition of a conventional ion source, the low energy cyclotron can perform the extremely high sensitivity /sup 14/C measurements that are now done at accelerator facilities. We found that no significant background is present when the cyclotron is tuned to accelerate /sup 14/C negative ions and the transmission efficiency is adequate to perform radiocarbon dating on milligram samples of carbon. The internal ion source used did not produce sufficient current to detect /sup 14/C directly at modern concentrations. We show how a conventional carbon negative ion source, located outside the cyclotron magnet, would produce sufficient beam and provide for quick sampling to make radiocarbon dating milligram samples with a modest laboratory instrument feasible.

  13. Detection of radiocarbon in the cyclotrino

    SciTech Connect

    Bertsche, K.J.; Karadi, C.A.; Muller, R.A.; Paulson, G.C.

    1990-04-01

    A small low energy cyclotron (the cyclotrino''), which was proposed for direct detection of radiocarbon in 1980, has now detected radiocarbon at natural abundance. This device combines the suppression of background through the use of negative ions with the high intrinsic mass resolution of a cyclotron. A high current cesium sputter negative ion source generates a beam of carbon ions which is pre-separated with Wien filter and is transported to the cyclotron via a series of electrostatic lenses. Beam is injected radially into the cyclotron using electrostatic deflectors and an electrostatic mirror. Axial focusing is entirely electrostatic. A microchannel plate detector is used with a phase-gated output. Data is presented showing resolution of radiocarbon at natural abundance. In its present form the system is capable of improving the sensitivity of detecting {sup 14}C in some biomedical experiments by a factor of 10{sup 4}. Modifications are discussed which could bring about an additional factor of 100 in sensitivity, which is important for archaeological and geological applications. Possibilities for measurements of other isotopes are discussed. 16 refs., 7 figs.

  14. Deglacial Atlantic Radiocarbon: A Southern Ocean Perspective

    NASA Astrophysics Data System (ADS)

    Robinson, L. F.; Burke, A.; Adkins, J. F.; Chen, T.; Spooner, P.

    2014-12-01

    It is widely accepted that the Southern Ocean is an important component of the climate system, acting as a key site for carbon and heat exchange between the atmosphere and oceans. The deglaciation with its associated millenial climate changes is a key time period for testing the mechanisms behind these exchanges. Ascertaining the precise timing of these events is a challenge given complications from variable and largely unconstrained reservoir ages, dissolution of carbonate hard parts and sediment redistribution by strong currents. Nevertheless improvements to our understanding of Southern Ocean dynamics in the past requires accurately-dated proxy records that can be embedded in GCM models. Radiocarbon measured in deep-sea corals offers just such an archive and proxy. Using the skeletons of deep-sea corals we are now able to reconstruct aspects of the history of three distinct water masses in the Drake Passage on a precise timescale, allowing direct comparison to U-series dated speleothem terrestrial records and polar ice cores. We present here a new deglacial radiocarbon record from the Drake Passage which more than doubles the resolution of published records. We focus on the deglacial, as well as providing insights from the contrasting period leading up to the LGM. Together with new data from far-field sites we interpret our results as evidence for a Southern Ocean control on atmospheric carbon dioxide and radiocarbon evolution during the deglaciation, and a northern hemisphere control during the run up to the LGM.

  15. Holocene age of the Yuha burial: Direct radiocarbon determinations by accelerator mass spectrometry

    USGS Publications Warehouse

    Stafford, Thomas W.; Jull, A.J.T.; Zabel, T.H.; Donahue, D.J.; Duhamel, R.C.; Brendel, K.; Haynes, C.V.; Bischoff, J.L.; Payen, L.A.; Taylor, R.E.

    1984-01-01

    The view that human populations may not have arrived in the Western Hemisphere before about 12,000 radiocarbon yr BP1,2 has been challenged by claims of much greater antiquity for a small number of archaeological sites and human skeleton samples. One such site is the Homo sapiens sapiens cairn burial excavated in 1971 from the Yuha desert, Imperial County, California3-5. Radiocarbon analysis of caliche coating one of the bones of the skeleton yielded a radiocarbon age of 21,500??1,000 yr BP4, while radiocarbon and uranium series analyses of caliche coating a cairn boulder yielded ages of 22,125??400 and 19,000??3,000 yr BP, respectively5. The late Pleistocene age assignment to the Yuha burial has been challenged by comparing the cultural context of the burial with other cairn burials in the same region6, on the basis of the site's geomorphological context and from radiocarbon analyses of soil caliches. 7,8 In rebuttal, arguments in defence of the original age assignment have been presented9,10 as well as an amino acid racemization analysis on the Yuha skeleton indicating an age of 23,600??2,600 yr BP11. The tandem accelerator mass spectrometer at the University of Arizona has now been used to measure the ratio of 14C/13C in several organic and inorganic fractions of post-cranial bone from the Yuha H. sapiens sapiens skeleton. Isotope ratios from six chemical fractions all yielded radiocarbon ages for the skeleton of less than 4,000 yr BP. These results indicate that the Yuha skeleton is of Holocene age, in agreement with the cultural context of the burial, and in disagreement with the previously assigned Pleistocene age of 19,000-23,000 yr. ?? 1984 Nature Publishing Group.

  16. What Are Cancer Disparities?

    Cancer.gov

    This infographic shows the factors associated with cancer disparities, examples of how the cancer burden differs across certain population groups, and NCI actions to understand and reduce cancer disparities.

  17. Application of Bomb Radiocarbon Chronologies to Shortfin Mako (Isurus oxyrinchus)

    SciTech Connect

    Ardizzone, D; Cailliet, G M; Natanson, L J; Andrews, A H; Kerr, L A; Brown, T A

    2007-07-16

    and the number of samples for MIA analysis was insufficient for some months. Hence, unequivocal validation of shortfin mako age estimates has yet to be accomplished. Atmospheric testing of thermonuclear devices in the 1950s and 1960s effectively doubled the natural atmospheric radiocarbon ({sup 14}C). The elevated {sup 14}C levels were first recorded in 1957-58, with a peak around 1963. As a consequence, {sup 14}C entered the ocean through gas exchange with the atmosphere at the ocean surface and in terrestrial runoff. Despite variable oceanographic conditions, a worldwide rise of the bomb {sup 14}C signal entered the ocean mixed layer as dissolved inorganic carbon (DIC) in 1957-58. The large amounts of {sup 14}C released from the bomb tests produced a signature that can be followed through time, throughout the marine food web, and into deeper waters. The marked increase of radiocarbon levels was first measured in the DIC of seawater and in biogenic marine carbonates of hermatypic corals in Florida. Subsequently, this record was documented in corals from other regions and in the thallus of rhodoliths. The accumulation of radiocarbon in the hard parts of most marine organisms in the mixed layer (such as fish otoliths and bivalves) was synchronous with the coral time-series. This technique has been used to validate age estimates and longevity of numerous bony fishes to date, as well as to establish bomb radiocarbon chronologies from different oceans. In the first application of this technique to lamnoid sharks, validated annual band-pair deposition in vertebral growth bands for the porbeagle (Lamna nasus) aged up to 26 years. Radiocarbon values from samples obtained from 15 porbeagle caught in the western North Atlantic Ocean (some of which were known-age) produced a chronology similar in magnitude to the reference carbonate chronology for that region. The observed phase shift of about 3 years was attributed to different sources of carbon between vertebrae and those for

  18. Disparity map estimation using image pyramid

    NASA Astrophysics Data System (ADS)

    Roszkowski, Mikołaj

    2013-10-01

    The task of a short baseline stereo matching algorithm is to calculate the disparity map given two rectified images of one scene. Most algorithms assume that a maximal possible disparity exists and search all disparities in the range from 1 to this maximal disparity. In the case of large images and wide disparity search range this can be very computationally demanding. In this article a simple coarse to fine hierarchical matching method based on the Gaussian pyramid and local stereo matching is investigated. Such an approach allows significant reduction of the number of disparities searched compared to the full search algorithm. Moreover it is shown, that grouping pixels into simple square regions is in most cases sufficient to avoid significant errors that typically appear at disparity map discontinuities when hierarchical schemes are used. Finally, it is presented that in most cases the quality of the disparity map obtained using the investigated algorithm is of comparable quality to a disparity map obtained using full-search local stereo algorithm.

  19. Radiocarbon dating of open systems with bomb effect

    SciTech Connect

    McKay, C.P.; Long, A.; Friedmann, E.I.

    1986-03-10

    The application of radiocarbon dating is extended to include systems that are slowly exchanging carbon with the atmosphere. Simple formulae are derived that relate the true age and the exchange rate of carbon to the apparent radiocarbon age. A radiocarbon age determination does not give a unique true age and exchange rate but determines a locus of values bounded by a minimum age and a minimum exchange rate. It is found that for radiocarbon ages as large as 10,000 years it is necessary to correct for the anthropogenic radiocarbon produced in the atmosphere by nuclear weapons testing. A one-term exponential approximation, with an e-folding time of 14.43 years, is used to model this effect and is shown to be accurate to within 3% for exchange time constants of 100 years and greater. The approach developed here is not specific to radiocarbon and can be applied to other radioisotopes in open systems.

  20. Radiocarbon dating of open systems with bomb effect

    NASA Technical Reports Server (NTRS)

    Mckay, C. P.; Long, A.; Friedmann, E. I.

    1986-01-01

    The application of radiocarbon dating is extended to include systems that are slowly exchanging carbon with the atmosphere. Simple formulae are derived that relate the true age and the exchange rate of carbon to the apparent radiocarbon age. A radiocarbon age determination does not give a unique true age and exchange rate but determines a locus of values bounded by a minimum age and a minimum exchange rate. It is found that for radiocarbon ages as large as 10,000 years it is necessary to correct for the anthropogenic radiocarbon produced in the atmosphere by nuclear weapons testing. A one-term exponential approximation, with an e-folding time of 14.43 years, is used to model this effect and is shown to be accurate to within 3 percent for exchange time constants of 100 years and greater. The approach developed here is not specific to radiocarbon and can be applied to other radioisotopes in open systems.

  1. New radiocarbon dates for terminal Pleistocene and early Holocene settlements in West Turkana, northern Kenya

    NASA Astrophysics Data System (ADS)

    Beyin, Amanuel; Prendergast, Mary E.; Grillo, Katherine M.; Wang, Hong

    2017-07-01

    The Turkana Basin in northern Kenya is located in an environmentally sensitive region along the eastern African Rift system. Lake Turkana's sensitivity to fluctuations in precipitation makes this an ideal place to study prehistoric human adaptations during key climatic transitions. Here we present eleven radiocarbon dates from two recently excavated sites in West Turkana, Kokito 01 and Kokito 02. The sites span the Pleistocene-Holocene transition, a time of fluctuating lake levels and novel cultural responses within the region. Several scenarios are laid out for the interpretation of site chronologies, and these are discussed with reference to the terminal Pleistocene and early Holocene chronological record for the region. Given the paucity of well-dated sites from this timespan in the Turkana Basin, the new radiocarbon dates are an important step toward establishing human settlement history and associated cultural developments in the region.

  2. What is binocular disparity?

    PubMed Central

    Lappin, Joseph S.

    2014-01-01

    What are the geometric primitives of binocular disparity? The Venetian blind effect and other converging lines of evidence indicate that stereoscopic depth perception derives from disparities of higher-order structure in images of surfaces. Image structure entails spatial variations of intensity, texture, and motion, jointly structured by observed surfaces. The spatial structure of binocular disparity corresponds to the spatial structure of surfaces. Independent spatial coordinates are not necessary for stereoscopic vision. Stereopsis is highly sensitive to structural disparities associated with local surface shape. Disparate positions on retinal anatomy are neither necessary nor sufficient for stereopsis. PMID:25161634

  3. Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century.

    PubMed

    Graven, Heather D

    2015-08-04

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon ((14)C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio (14)C/C in atmospheric CO2 (Δ(14)CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ(14)CO2 because fossil fuels have lost all (14)C from radioactive decay. Simulations of Δ(14)CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ(14)CO2 near the preindustrial level of 0‰ through 2100, whereas "business-as-usual" emissions will reduce Δ(14)CO2 to -250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial "aging" of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old.

  4. Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century

    PubMed Central

    Graven, Heather D.

    2015-01-01

    Radiocarbon analyses are commonly used in a broad range of fields, including earth science, archaeology, forgery detection, isotope forensics, and physiology. Many applications are sensitive to the radiocarbon (14C) content of atmospheric CO2, which has varied since 1890 as a result of nuclear weapons testing, fossil fuel emissions, and CO2 cycling between atmospheric, oceanic, and terrestrial carbon reservoirs. Over this century, the ratio 14C/C in atmospheric CO2 (Δ14CO2) will be determined by the amount of fossil fuel combustion, which decreases Δ14CO2 because fossil fuels have lost all 14C from radioactive decay. Simulations of Δ14CO2 using the emission scenarios from the Intergovernmental Panel on Climate Change Fifth Assessment Report, the Representative Concentration Pathways, indicate that ambitious emission reductions could sustain Δ14CO2 near the preindustrial level of 0‰ through 2100, whereas “business-as-usual” emissions will reduce Δ14CO2 to −250‰, equivalent to the depletion expected from over 2,000 y of radioactive decay. Given current emissions trends, fossil fuel emission-driven artificial “aging” of the atmosphere is likely to occur much faster and with a larger magnitude than previously expected. This finding has strong and as yet unrecognized implications for many applications of radiocarbon in various fields, and it implies that radiocarbon dating may no longer provide definitive ages for samples up to 2,000 y old. PMID:26195757

  5. Watershed storage and riverine particulate organic radiocarbon

    NASA Astrophysics Data System (ADS)

    Blair, N. E.; Leithold, E. L.

    2011-12-01

    Lateral movement of carbon and other materials across landscapes is punctuated with periods of storage and reaction. Though we understand basic principles concerning transport and storage effects on the nature of some materials, an adequate understanding is lacking of the cumulative impacts of those processes as material migrates across the biogeochemical landscape. This is essential to the interpretation of geochemical soil and sedimentary records of the past as well as to predicting future responses of systems to perturbations in climate or landuse. Sources of organic carbon exported from watersheds can be broadly defined as those recently derived for extant ecosystems, those derived from materials aged and altered in storage (aged soil OC), and fossil material associated with sedimentary bedrock. Separately, these materials are easy to recognize based on isotopic and molecular compositions and each could in principle be linked to specific mass transport processes such as sheet wash, shallow landsliding or gullying. The blending and alteration of original source signatures during storage appear to attenuate the variability of the exported signal within a system and complicate source identification. Riverine particulate organic carbon 14C-compositions reveal robust relationships between radiocarbon content, suspended load concentrations and % organic C. These are explained as a result of mixing of the 14C-free fossil C from sedimentary rocks with 14C-containing material derived from extant ecosystems and soils. In essence, the 14C-content of riverine POC inversely correlates with the muddiness of the system. Whereas one might predict that POC radiocarbon content might decrease with increased storage or residence time in watersheds, no obvious relationship exists between bulk 14C-content observations and watershed size. Instead, the hypothetical watershed size effect is obscured by precipitation- and discharge-driven variations in the mixture of the fossil and non

  6. The North Atlantic Tritium and Radiocarbon Transients 1972-1983

    NASA Astrophysics Data System (ADS)

    Göte Östlund, H.; Rooth, Claes G. H.

    1990-11-01

    Deep ventilation and water mass transformation processes in the North Atlantic, on decadal time scales, are illustrated by the evolving distribution patterns of anthropogenic tritium and radiocarbon. Data from two quasisynoptic surveys of the interior of the North Atlantic, the Geochemical Ocean Sections Study (GEOSECS) and complementary oceanographic observation projects in 1972, and the Transient Tracers in the Oceans (TTO) in 1981 and 1983, are presented in comparative cross sections and maps representing conditions roughly one and two decades, respectively, after the first major tracer injections. The discussion emphasizes comparisons of the decay corrected tritium concentration fields, which show several distinct regimes of transient evolution, including examples of surprising constancy in some regional patterns. While largely supportive of previous qualitative ideas about transport patterns, these results also suggest that the patterns of deep water injection in high latitudes must have undergone a major change around or soon after the time of GEOSECS (1972), involving a major increase in supply of Upper North Atlantic Deep Water. The near-surface waters show strong signatures of tropical (low tritium) influence in the southwestern and western part of the subtropical gyre, while the northeastern part is influenced by continued tritium input from Arctic surface waters. Strong evidence for distinct sub-basin-scale interior circulation domains is found in the fact that the major distribution regime transitions seen in the GEOSECS data are observed again in TTO, and thus maintained through the second decade of the transient. The radiocarbon data set, which reflects the addition to the natural background distribution, supports the significance also on longer time scales of the mid-depth regime transition around 30°N latitude.

  7. Calibration of the radiocarbon time scale at 37ka BP

    SciTech Connect

    Southon, J.R.; Deino, A.L.; Orsi, G.

    1995-12-01

    Results from radiocarbon and U-Th measurements on corals have provided a radiocarbon calibration beyond the range covered by tree ring series, but the uncertainties in the measurements beyond 20ka BP are very large. We have obtained new calibration data from radiocarbon dates on material associated with the catastrophic Campanian Ignimbrite eruption from the Phlegrean Fields near Naples. The eruption has been well dated by {sup 40}Ar/{sup 39}Ar to 37ka BP. Radiocarbon measurements were carried out on charcoal from a carbonized branch exposed within the ignimbrite tuff on the wall of an active quarry. The sample was split and analyzed at both the Naples and Lawrence Livermore AMS facilities. The offset between the Ar-Ar data and the radiocarbon results (recalculated using the true 5730-year half life for {sup 14}C) is consistent with predictions from paleomagnetic data and carbon cycle modeling.

  8. Upper-ocean-to-atmosphere radiocarbon offsets imply fast deglacial carbon dioxide release.

    PubMed

    Rose, Kathryn A; Sikes, Elisabeth L; Guilderson, Thomas P; Shane, Phil; Hill, Tessa M; Zahn, Rainer; Spero, Howard J

    2010-08-26

    Radiocarbon in the atmosphere is regulated largely by ocean circulation, which controls the sequestration of carbon dioxide (CO(2)) in the deep sea through atmosphere-ocean carbon exchange. During the last glaciation, lower atmospheric CO(2) levels were accompanied by increased atmospheric radiocarbon concentrations that have been attributed to greater storage of CO(2) in a poorly ventilated abyssal ocean. The end of the ice age was marked by a rapid increase in atmospheric CO(2) concentrations that coincided with reduced (14)C/(12)C ratios (Delta(14)C) in the atmosphere, suggesting the release of very 'old' ((14)C-depleted) CO(2) from the deep ocean to the atmosphere. Here we present radiocarbon records of surface and intermediate-depth waters from two sediment cores in the southwest Pacific and Southern oceans. We find a steady 170 per mil decrease in Delta(14)C that precedes and roughly equals in magnitude the decrease in the atmospheric radiocarbon signal during the early stages of the glacial-interglacial climatic transition. The atmospheric decrease in the radiocarbon signal coincides with regionally intensified upwelling and marine biological productivity, suggesting that CO(2) released by means of deep water upwelling in the Southern Ocean lost most of its original depleted-(14)C imprint as a result of exchange and isotopic equilibration with the atmosphere. Our data imply that the deglacial (14)C depletion previously identified in the eastern tropical North Pacific must have involved contributions from sources other than the previously suggested carbon release by way of a deep Southern Ocean pathway, and may reflect the expanded influence of the (14)C-depleted North Pacific carbon reservoir across this interval. Accordingly, shallow water masses advecting north across the South Pacific in the early deglaciation had little or no residual (14)C-depleted signals owing to degassing of CO(2) and biological uptake in the Southern Ocean.

  9. Insights into soil carbon dynamics across climatic gradients from carbon-pool specific radiocarbon analyses

    NASA Astrophysics Data System (ADS)

    van der Voort, Tessa Sophia; Hagedorn, Frank; McIntyre, Cameron; Zell, Claudia; Eglinton, Timothy Ian

    2017-04-01

    Soil carbon constitutes the largest terrestrial reservoir of organic carbon, and therefore understanding the mechanisms and drivers of carbon stabilization is crucial, especially in the framework of climate change. The understanding of the dependence of soil organic turnover in specific carbon pools as related to e.g. climate, soil texture and mineralogy is limited. In this framework, radiocarbon constitutes a uniquely powerful tool that help to unravel carbon dynamics from decadal to millennial timescales. This project combines bulk and pool-specific radiocarbon analyses in the top and deep soil on a wide range of forested soils that span a large climatic gradient (MAT 1.3-9.2°C, MAP 600 to 2100 mm m-2y-1). These well-studies sites are part of the Long-Term Forest Ecosystem Research (LWF) program of the Swiss Federal Institute for Forest, Snow and Landscape research (WSL). This study aims to combine the insights gained from bulk and pool-specific turnover to environmental conditions and molecular composition of soil carbon. The pools investigated span the mineral-associated (occluded and heavy fractions from density fractionation) and potentially water-soluble (free light fractions from density fractionation and water extractable organic carbon) organic carbon fractions. Pool-specific radiocarbon work is augmented by the measurement of abundance of compounds such as alkanes, fatty acids and lignin phenols on a subset of samples. Initial results show disparate patterns depending on soil type and in particular soil texture, which could be indicative of various stabilization mechanisms in different soils. Overall, this study provides new insights into the controls of soil organic matter dynamics as related to environmental conditions, in particular in specific sub-pools of carbon.

  10. Educational Disparities and Conflict: Evidence from Lebanon

    ERIC Educational Resources Information Center

    Tfaily, Rania; Diab, Hassan; Kulczycki, Andrzej

    2013-01-01

    This article examines the impact of Lebanon's civil war (1975-1991) on disparities in education among the country's main religious sects and across various regions. District of registration is adopted as a proxy for religious affiliation through a novel, detailed classification to assess sectarian differentials by region and regional differentials…

  11. Educational Disparities and Conflict: Evidence from Lebanon

    ERIC Educational Resources Information Center

    Tfaily, Rania; Diab, Hassan; Kulczycki, Andrzej

    2013-01-01

    This article examines the impact of Lebanon's civil war (1975-1991) on disparities in education among the country's main religious sects and across various regions. District of registration is adopted as a proxy for religious affiliation through a novel, detailed classification to assess sectarian differentials by region and regional differentials…

  12. Radiocarbon positive-ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Freeman, Stewart P. H. T.; Shanks, Richard P.; Donzel, Xavier; Gaubert, Gabriel

    2015-10-01

    Proof-of-principle of a new mass spectrometric technique for radiocarbon measurement is demonstrated. Interfering nitrogen and hydrocarbon molecules are largely eliminated in a charge-exchange cell operating on non-metallic gas. The positive-to-negative ion conversion is the reverse of that conventionally used in accelerator mass spectrometry (AMS) and is compatible with plasma ion sources that may be significantly more efficient and capable of greater output than are AMS sputter ion sources. The Nanogan electron cyclotron resonance (ECR) ion source employed exhibited no sample memory and the >50 kyrs age range of AMS was reproduced. A bespoke prototype new instrument is now required to optimise the plasma and cell physics and to realise hypothetical performance gains over AMS.

  13. Health Disparity and Cancer Health Disparity in China.

    PubMed

    Wang, Qi; Jiao, Jie

    2016-01-01

    China is one of the largest and most populated countries in the world. It has undergone rapid economic growth in recent years. However, the development is not equitable, and the distribution of wealth significantly varies among the regions in China. Geographical and socioeconomic inequalities, together with the lack of an equitable national social support system, cause the high variance of health outcomes among the regions. Furthermore, the fast growth of the economy has evoked many environmental challenges and puts much pressure on the population. The severe environmental deterioration, especially of the atmosphere and water bodies, has affected the health of the people living in China. As a result, cancer has become a major public health issue, and an alarming increase in incidence and mortality has been reported. However, cancer incidence and mortality vary in different areas in China. Cancer and cancer treatment disparities have existed for years. This article will discuss the existing health and cancer disparities associated with the risk factors and how these disparities are managed in China.

  14. Health Disparity and Cancer Health Disparity in China

    PubMed Central

    Wang, Qi; Jiao, Jie

    2016-01-01

    China is one of the largest and most populated countries in the world. It has undergone rapid economic growth in recent years. However, the development is not equitable, and the distribution of wealth significantly varies among the regions in China. Geographical and socioeconomic inequalities, together with the lack of an equitable national social support system, cause the high variance of health outcomes among the regions. Furthermore, the fast growth of the economy has evoked many environmental challenges and puts much pressure on the population. The severe environmental deterioration, especially of the atmosphere and water bodies, has affected the health of the people living in China. As a result, cancer has become a major public health issue, and an alarming increase in incidence and mortality has been reported. However, cancer incidence and mortality vary in different areas in China. Cancer and cancer treatment disparities have existed for years. This article will discuss the existing health and cancer disparities associated with the risk factors and how these disparities are managed in China. PMID:28083550

  15. Cancer Disparities - Cancer Currents Blog

    Cancer.gov

    Blog posts on cancer health disparities research—including factors that influence disparities, disparities-related research efforts, and diversity in the cancer research workforce—from NCI Cancer Currents.

  16. The Marine Radiocarbon Reservoir Effect and its correlation with the ocean dynamics

    NASA Astrophysics Data System (ADS)

    Queiroz Alves, E.

    2016-02-01

    The marine reservoir effect (MRE) is closely related to the ocean dynamics of each region and, therefore, can be used as a powerful tool to understand ocean circulation. Radiocarbon measurements on marine taxa and/or water masses can be related to density and temperature data to yield an useful picture of coastal processes. This study presents MRE data for the Brazilian coast, where the two main ocean currents display different features. The Brazil current carries warm subtropical waters while the Falklands current is composed by cold subantartic waters. They flow in opposite directions along the coast and their encounter, around 38S, creates a strong thermohaline front referred to as Brazil-Falklands Confluence (Roden, 1986; Gordon,1989). Radiocarbon dating of marine species was performed for different regions on the Brazilian coast. The use of samples from both, archaeological sites and museum collections, can give a consistent time frame for changes in the MRE and, potentially, in the South Atlantic Ocean circulation patterns. Moreover, seasonally or annually resolved coral carbon concentration measurements constitute a convenient tool for assessing sea-water radiocarbon signatures (Druffel and Linick, 1978; Dunbar and Colle, 1999; Druffel et al., 2007). These measurements are being performed in an attempt of creating a coral-based database for radiocarbon variability in the South Atlantic Ocean through time. Dunbar, R. G., and J. E. Cole (1999), Annual records of tropical systems (ARTS), Workshop Rep., 99-1, 72pp., Past Global Changes, Bern. Druffel, E. R. M., and T.W. Linick (1978), Radiocarbon in annual coral rings of Florida, J. Geophys. Res. Lett., 5(11), 913-917. Druffel, E. R. M., S. Griffin, S. R. Beaupre, and R. B. Dunbar (2007), Oceanic climate and circulation changes during the past four centuries from radiocarbon in corals, Geophys. Res. Lett., 34, L09601. Gordon, A. L. (1989), Brazil-Malvinas Confluence - 1984. Deep Sea Research, 36, 359-384. Roden

  17. Millennial-scale variability in the local radiocarbon reservoir age of the Florida Keys reef tract during the Holocene

    NASA Astrophysics Data System (ADS)

    Ashe, E.; Toth, L. T.; Cheng, H.; Edwards, R. L.; Richey, J. N.

    2016-12-01

    The oceanic passage between the Florida Keys and Cuba, known as the Straits of Florida, provides a critical connection between the tropics and northern Atlantic. Changes in the character of water masses transported through this region may ultimately have important impacts on high-latitude climate variability. Although recent studies have documented significant changes in the density of regional surface waters over millennial timescales, little is known about the contribution of local- to regional-scale changes in circulation to surface-water variability. Local variability in the radiocarbon age, ΔR, of surface waters can be used to trace changes in local water-column mixing and/or changes in regional source water over a variety of spatial and temporal scales. We reconstructed "snapshots" of ΔR variability across the Florida Keys reef tract during the last 10,000 years by dating 68 unaltered corals collected from Holocene reef cores with both U-series and radiocarbon techniques. We combined the snapshots of ΔR into a semi-empirical model to develop a robust statistical reconstruction of millennial-scale variability in ΔR on the Florida Keys reef tract. Our model demonstrates that ΔR varied significantly during the Holocene, with relatively high values during the early Holocene and around 3000 years BP and relatively low values around 7000 years BP and at present. We compare the trends in ΔR to existing paleoceanographic reconstructions to evaluate the relative contribution of local upwelling versus changes in source water to the region as a whole in driving local radiocarbon variability, and discuss the importance of these results to our understanding of regional-scale oceanographic and climatic variability during the Holocene. We also discuss the implications of our results for radiocarbon dating of marine samples from south Florida and present a model of ΔR versus 14C age that can be used to improve the accuracy of radiocarbon calibrations from this region.

  18. Radiocarbon dating of twentieth century works of art

    NASA Astrophysics Data System (ADS)

    Petrucci, F.; Caforio, L.; Fedi, M.; Mandò, P. A.; Peccenini, E.; Pellicori, V.; Rylands, P.; Schwartzbaum, P.; Taccetti, F.

    2016-11-01

    The atmospheric tests of nuclear weapons caused a sudden increase in the radiocarbon concentration in the atmosphere from 1955, reaching its maximum value in 1963-1965. Once the nuclear tests in the atmosphere were halted, the 14C concentration started to decrease. This behavior of the radiocarbon concentration is called the "Bomb Peak", and it has successfully been used as a tool for high-precision radiocarbon measurements, in forensic sciences and biology. In the art field, the possibility of dating canvas, wood and paper, widely used as supports for paintings, may be an invaluable tool in modern art studies.

  19. Radiocarbon dating casts doubt on the late chronology of the Middle to Upper Palaeolithic transition in southern Iberia

    PubMed Central

    Wood, Rachel E.; Barroso-Ruíz, Cecilio; Caparrós, Miguel; Jordá Pardo, Jesús F.; Galván Santos, Bertila; Higham, Thomas F. G.

    2013-01-01

    It is commonly accepted that some of the latest dates for Neanderthal fossils and Mousterian industries are found south of the Ebro valley in Iberia at ca. 36 ka calBP (calibrated radiocarbon date ranges). In contrast, to the north of the valley the Mousterian disappears shortly before the Proto-Aurignacian appears at ca. 42 ka calBP. The latter is most likely produced by anatomically modern humans. However, two-thirds of dates from the south are radiocarbon dates, a technique that is particularly sensitive to carbon contaminants of a younger age that can be difficult to remove using routine pretreatment protocols. We have attempted to test the reliability of chronologies of 11 southern Iberian Middle and early Upper Paleolithic sites. Only two, Jarama VI and Zafarraya, were found to contain material that could be reliably dated. In both sites, Middle Paleolithic contexts were previously dated by radiocarbon to less than 42 ka calBP. Using ultrafiltration to purify faunal bone collagen before radiocarbon dating, we obtain ages at least 10 ka 14C years older, close to or beyond the limit of the radiocarbon method for the Mousterian at Jarama VI and Neanderthal fossils at Zafarraya. Unless rigorous pretreatment protocols have been used, radiocarbon dates should be assumed to be inaccurate until proven otherwise in this region. Evidence for the late survival of Neanderthals in southern Iberia is limited to one possible site, Cueva Antón, and alternative models of human occupation of the region should be considered. PMID:23382220

  20. Disparity and shading cues cooperate for surface interpolation.

    PubMed

    Vuong, Quoc C; Domini, Fulvio; Caudek, Corrado

    2006-01-01

    In two experiments, we tested whether disparity and shading cues cooperated for surface interpolation. Observers adjusted a probe dot to/lie on a surface specified either by a sparse disparity field, a continuous stereo shading or monocular shading gradient, or both cues. Observers' adjustments were very consistent with disparity information but their adjustments were much more variable with shading information. However, observers significantly improved their precision when both cues were present, relative to when only disparity information was present. These results cannot be explained by assuming that separate modules analyze disparity and shading information, even if observers optimally combined these cues. Rather, we attribute this improvement to a process through which the shading gradient constrains the disparity field in regions where disparities cannot be directly measured. This cooperative process may be based on the natural covariation existing between these cues produced by the retinal projection of smooth surfaces.

  1. Advancing the use of radiocarbon in studies of global and regional carbon cycling with high precision measurements of carbon-14 in carbon dioxide from the Scripps Carbon Dioxide Program

    NASA Astrophysics Data System (ADS)

    Graven, Heather Dawn

    Measurements of 14C in atmospheric CO2 have served as a powerful geochemical tracer since the first observation programs began over 50 years ago. As the nuclear weapons tests of the 1950s and 60s caused an enormous perturbation to natural atmospheric 14C levels, tracking the response of 14C in CO2 provided a measure of exchange rates between different regions of the atmosphere and between the troposphere and the ocean surface and terrestrial biosphere. Early measurements of 14C/12C, or Delta14 C, in tree rings provided clear evidence that rising CO2 concentrations were due to human activities by revealing the dilution of 14C in the atmosphere by the combustion of million year old fossil carbon, a process termed the "Suess Effect". This thesis aimed to continue and expand the use of Delta14 C in atmospheric CO2 for investigating carbon cycle dynamics. Since much of the excess 14C derived from nuclear weapons testing has been redistributed into oceanic and biospheric reservoirs, trends and gradients in Delta14C of CO2 have diminished to levels that are nearly commensurate with measurement precision at most laboratories. Development of improved methods for Delta14C analysis by accelerator mass spectrometry at Lawrence Livermore National Laboratory advanced measurement uncertainty to 1.7‰. Application of the improved analytical procedures to an archive of CO 2 samples from the Scripps CO2 Program produced 2-15 year monthly time series of Delta14C at seven global sampling stations. The high precision observations show variability in the secular trend of Delta14C that could enable new insights to the climatic influences on CO2 exchange. Measurement of a shift in the Delta 14C gradient between the Northern and Southern Hemispheres since the 1980s also places constraints on regional fluxes of carbon, with particular relevance to Southern Ocean dynamics. The measurements presented here contribute significantly to the amount and global coverage of recent Delta14 C

  2. Radiocarbon signal of a low and intermediate level radioactive waste disposal facility in nearby trees.

    PubMed

    Janovics, R; Kelemen, D I; Kern, Z; Kapitány, S; Veres, M; Jull, A J T; Molnár, M

    2016-03-01

    Tree ring series were collected from the vicinity of a Hungarian radioactive waste treatment and disposal facility and from a distant control background site, which is not influenced by the radiocarbon discharge of the disposal facility but it represents the natural regional (14)C level. The (14)C concentration of the cellulose content of tree rings was measured by AMS. Data of the tree ring series from the disposal facility was compared to the control site for each year. The results were also compared to the (14)C data of the atmospheric (14)C monitoring stations at the disposal facility and to international background measurements. On the basis of the results, the excess radiocarbon of the disposal facility can unambiguously be detected in the tree from the repository site. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Significance of the distribution of bomb-produced radiocarbon in the ocean

    SciTech Connect

    Peng, T.H.

    1985-01-01

    The pattern of global water column inventories of bomb-produced radiocarbon suggests that a sizable portion of the bomb radiocarbon that entered the Antarctic, the northern Pacific, and the tropical oceans has been transported to the adjacent temperate regions. Models of lateral transport of surface water in the Atlantic, Indian, and Pacific Oceans are designed on the basis of this distribution pattern. Upwelling of bomb-radiocarbon-free water from below takes place in the Antarctic, the northern Pacific, and the tropical regions; and downwelling of surface water occurs in the temperate oceans and in the northern Atlantic. Uptake of excess CO/sub 2/ by these models is calculated using the observed Mauna Loa pCO/sub 2/ record as an input function. Results indicate that 35 percent of fossil fuel CO/sub 2/ is taken up by these model oceans during the period 1958-1980. Considering the observed airborne fraction of 0.55, it appears that about 10 percent of the global fossil fuel CO/sub 2/ is still missing. 24 refs., 5 tabs.

  4. Insights into soil carbon dynamics across climatic and geologic gradients from temporally-resolved radiocarbon measurements

    NASA Astrophysics Data System (ADS)

    van der Voort, T. S.; Hagedorn, F.; Mannu, U.; Walthert, L.; McIntyre, C.; Eglinton, T. I.

    2016-12-01

    Soil carbon constitutes the largest terrestrial reservoir of organic carbon, and therefore quantifying soil organic matter dynamics (carbon turnover, stocks and fluxes) across spatial gradients is essential for an understanding of the carbon cycle and the impacts of global change. In particular, links between soil carbon dynamics and different climatic and compositional factors remains poorly understood. Radiocarbon constitutes a powerful tool for unraveling soil carbon dynamics. Temporally-resolved radiocarbon measurements, which take advantage of "bomb-radiocarbon"-driven changes in atmospheric 14C, enable further constraints to be placed on C turnover times. These in turn can yield more precise flux estimates for both upper and deeper soil horizons. This project combines bulk radiocarbon measurements on a suite of soil profiles spanning strong climatic (MAT 1.3-9.2°C, MAP 600 to 2100 mm m-2y-1) and geologic gradients with a more in-depth approach for a subset of locations. For this subset, temporal and carbon-fraction specific radiocarbon data has been acquired for both topsoil and deeper soils. These well-studied sites are part of the Long-Term Forest Ecosystem Research (LWF) program of the Swiss Federal Institute for Forest, Snow and Landscape research (WSL). Resulting temporally-resolved turnover estimates are coupled to carbon stocks, fluxes across this wide range of forest ecosystems and are examined in the context of environmental drivers (temperature, precipitation, primary production and soil moisture) as well as composition (sand, silt and clay content). Statistical analysis on the region-scale - correlating radiocarbon signature with climatic variables such as temperature, precipitation, primary production and elevation - indicates that composition rather than climate is a key driver of ­­Δ14C signatures. Estimates of carbon turnover, stocks and fluxes derived from temporally-resolved measurements highlight the pivotal role of soil moisture as a

  5. Challenges faced when using radiocarbon measurements to estimate fossil fuel emissions in the UK.

    NASA Astrophysics Data System (ADS)

    Wenger, A.; O'Doherty, S.; Rigby, M. L.; Ganesan, A.; Manning, A.; Allen, G.

    2015-12-01

    Estimating the anthropogenic component of carbon dioxide emissions from direct atmospheric measurements is difficult, due to the large natural carbon dioxide fluxes. One way of determining the fossil fuel component of atmospheric carbon dioxide is the use of radiocarbon measurements. Whilst carbon reservoirs with a reasonably fast carbon exchange rate all have a similar radiocarbon content, fossil fuels are completely devoid of radiocarbon due to their age. Previous studies have 14CO2 (UK) this approach is compromised by the high density of 14CO2 emitting nuclear power plants. Of the 16 nuclear reactors in the UK, 14 are advanced gas cooled reactors, which have one of the highest 14CO2 emission rates of all reactor types. These radiocarbon emissions not only lead to a serious underestimation of the recently added fossil fuel CO2, by masking the depletion of 14C in CO2, but can in fact overshadow the depletion by a factor of 2 or more. While a correction for this enhancement can be applied, the emissions from the nuclear power plants are highly variable, and an accurate correction is therefore not straightforward. We present the first attempt to quantify UK fossil fuel CO2 emissions through the use of 14CO2. We employ a sampling strategy that makes use of a Lagrangian particle dispersion model, in combination with nuclear industry emission estimates, to forecast "good" sampling times, in an attempt to minimize the correction due to emissions from the nuclear industry. As part of the Greenhouse gAs Uk and Global Emissions (GAUGE) project, 14CO2measurements are performed at two measurement sites in the UK and Ireland, as well as during science flights around the UK. The measurement locations have been chosen with a focus on high emitting regions such as London and the Midlands. We discuss the unique challenges that face the determination of fossil fuel emissions through radiocarbon measurements in the UK and our sampling strategy to deal with them. In addition we

  6. Optimization of simultaneous tritium–radiocarbon internal gas proportional counting

    SciTech Connect

    Bonicalzi, R. M.; Aalseth, C. E.; Day, A. R.; Hoppe, E. W.; Mace, E. K.; Moran, J. J.; Overman, C. T.; Panisko, M. E.; Seifert, A.

    2016-03-01

    Specific environmental applications can benefit from dual tritium and radiocarbon measurements in a single compound. Assuming typical environmental levels, it is often the low tritium activity relative to the higher radiocarbon activity that limits the dual measurement. In this paper, we explore the parameter space for a combined tritium and radiocarbon measurement using a methane sample mixed with an argon fill gas in low-background proportional counters of a specific design. We present an optimized methane percentage, detector fill pressure, and analysis energy windows to maximize measurement sensitivity while minimizing count time. The final optimized method uses a 9-atm fill of P35 (35% methane, 65% argon), and a tritium analysis window from 1.5 to 10.3 keV, which stops short of the tritium beta decay endpoint energy of 18.6 keV. This method optimizes tritium counting efficiency while minimizing radiocarbon beta decay interference.

  7. Radiocarbon dating of a very large African baobab.

    PubMed

    Patrut, Adrian; von Reden, Karl F; Lowy, Daniel A; Alberts, Andries H; Pohlman, John W; Wittmann, Rudolf; Gerlach, Dana; Xu, Li; Mitchell, Clark S

    2007-11-01

    In late 2004, Grootboom, probably the largest known African baobab (Adansonia digitata L.), collapsed unexpectedly in northeastern Namibia. Ten wood samples collected from different areas of the trunk were processed and investigated by accelerator mass spectrometry radiocarbon dating. The radiocarbon dates of three samples were greater than 1000 years BP (radiocarbon years before present, i.e., before AD 1950). The corresponding calibrated calendar age of the oldest sample was 1275 +/- 50 years, making Grootboom the oldest known angiosperm tree with reliable dating results. Variations in radiocarbon dates among the wood samples indicated that, morphologically, Grootboom was a quintuple tree, whereas genetically, it was a single individual. Ages of extreme lateral samples revealed that, over the past 500-600 years, Grootbooom had almost ceased growing, providing information about climate changes in central southern Africa. The sudden demise of Grootboom coincided with the spread of the poorly studied baobab disease, which has become epidemic in Namibia.

  8. Optimization of simultaneous tritium-radiocarbon internal gas proportional counting

    NASA Astrophysics Data System (ADS)

    Bonicalzi, R. M.; Aalseth, C. E.; Day, A. R.; Hoppe, E. W.; Mace, E. K.; Moran, J. J.; Overman, C. T.; Panisko, M. E.; Seifert, A.

    2016-03-01

    Specific environmental applications can benefit from dual tritium and radiocarbon measurements in a single compound. Assuming typical environmental levels, it is often the low tritium activity relative to the higher radiocarbon activity that limits the dual measurement. In this paper, we explore the parameter space for a combined tritium and radiocarbon measurement using a natural methane sample mixed with an argon fill gas in low-background proportional counters of a specific design. We present an optimized methane percentage, detector fill pressure, and analysis energy windows to maximize measurement sensitivity while minimizing count time. The final optimized method uses a 9-atm fill of P35 (35% methane, 65% argon), and a tritium analysis window from 1.5 to 10.3 keV, which stops short of the tritium beta decay endpoint energy of 18.6 keV. This method optimizes tritium-counting efficiency while minimizing radiocarbon beta-decay interference.

  9. Assessing screening criteria for the radiocarbon dating of bone mineral

    NASA Astrophysics Data System (ADS)

    Fernandes, Ricardo; Hüls, Matthias; Nadeau, Marie-Josée; Grootes, Pieter M.; Garbe-Schönberg, C.-Dieter; Hollund, Hege I.; Lotnyk, Andriy; Kienle, Lorenz

    2013-01-01

    Radiocarbon dating of bone mineral (carbonate in the apatite lattice) has been the target of sporadic research for the last 40 years. Results obtained by different decontamination protocols have, however, failed to provide a consistent agreement with reference ages. In particular, quality criteria to assess bone mineral radiocarbon dating reliability are still lacking. Systematic research was undertaken to identify optimal preservation criteria for bone mineral in archeological bones. Six human long bones, originating from a single site, were radiocarbon-dated both for collagen and apatite, with the level of agreement between the dates providing an indication of exogenous carbon contamination. Several techniques (Histology, FTIR, TEM, LA-ICP-MS) were employed to determine the preservation status of each sample. Research results highlight the importance of a micro-scale approach in establishing bone preservation, in particular the use of trace element concentration profiles demonstrated its potential use as a viable sample selection criterion for bone carbonate radiocarbon dating.

  10. Constraining the shallow subtropical overturning circulation with archived radiocarbon records

    NASA Astrophysics Data System (ADS)

    Rosenheim, B. E.; Swart, P. K.; Thorrold, S. R.; Roberts, M. L.

    2007-12-01

    Archived radiocarbon records in accretionary skeletons can be used to constrain the shallow overturning subtropical cells (STC's) that transport significant amounts of tropical heat poleward in the world's oceans. Radiocarbon values of DIC in the world's oceans reflect a continuum between waters residing on the surface over long periods (high Δ14C due to equilibration with "modern" atmosphere) and waters decoupled from the atmosphere in the abyss (low Δ14C due to radioisotope decay), as well as mixtures between water masses of different ages. Thus, measurements of radiocarbon have demonstrated utility in assessing convective heat tranport such as the Meridional Overturning Circulation that is central to global climate. A prominent radiocarbon gradient is also present between the subsiding subtropical surface waters and the upwelling equatorial surface waters in the world's oceans due to the presence of STC's. These convection cells transport a major proportion of tropical heat in the Pacific and a significant proportion of tropical heat in the Atlantic towards the poles. Archived radiocarbon records in surface corals and subsurface sclerosponges constrain the N. Atlantic STC's on a centennial time scale. Published short records from Cape Verde corals indicate significant changes in radiocarbon content; this is potentially related to migration of the front between upwelled tropical waters and downwelled subtropical waters. An approach is outlined to estimate the proportion of tropical to subtropical waters at Cape Verde using as endmembers high-resolution sclerosponge radiocarbon records from Bahamas subsurface waters and coral radiocarbon records from São Tome and Principe in the Gulf of Guinea. Preliminary data from Bahamas sclerosponges indicate the need for high-resolution subsampling of the skeletons. Initial novel AMS measurements from fine scale laser-decomposition of the skeletons are presented.

  11. Investigating bomb radiocarbon transport in the southern Pacific Ocean with otolith radiocarbon

    NASA Astrophysics Data System (ADS)

    Grammer, G. L.; Fallon, S. J.; Izzo, C.; Wood, R.; Gillanders, B. M.

    2015-08-01

    To explore the transport of carbon into water masses from the surface ocean to depths of ∼ 1000 m in the southwest Pacific Ocean, we generated time series of radiocarbon (Δ14C) from fish otoliths. Otoliths (carbonate earstones) from long-lived fish provide an indirect method to examine the "bomb pulse" of radiocarbon that originated in the 1950s and 1960s, allowing identification of changes to distributions of 14C that has entered and mixed within the ocean. We micro-sampled ocean perch (Helicolenus barathri) otoliths, collected at ∼ 400- 500 m in the Tasman Sea, to obtain measurements of Δ14C for those depths. We compared our ocean perch Δ14C series to published otolith-based marine surface water Δ14C values (Australasian snapper (Chrysophrys auratus) and nannygai (Centroberyx affinis)) and to published deep-water values (800-1000 m; orange roughy (Hoplostethus atlanticus)) from the southwest Pacific to establish a mid-water Δ14C series. The otolith bomb 14C results from these different depths were consistent with previous water mass results in the upper 1500 m of the southwest Pacific Ocean (e.g. World Ocean Circulation Experiment and Geochemical Ocean Sections Study). A comparison between the initial Δ14C bomb pulse rise at 400-500 m suggested a ventilation lag of 5 to 10 yr, whereas a comparison of the surface and depths of 800-1000 m detailed a 10 to 20 yr lag in the time history of radiocarbon invasion at this depth. Pre-bomb reservoir ages derived from otolith 14C located in Tasman Sea thermocline waters were ∼ 530 yr, while reservoir ages estimated for Tasman Antarctic intermediate water were ∼ 730 yr.

  12. Rural Health Disparities

    MedlinePlus

    ... Health Gateway Evidence-based Toolkits Rural Health Models & Innovations Supporting Rural Community Health Tools for Success Am ... Update of the Rural-Urban Chartbook Highlights current trends and disparities across different levels of metro- and ...

  13. Disparities in Oral Health

    MedlinePlus

    ... Tips Disparities in Oral Health Oral Health Conditions Periodontal Disease Community Water Fluoridation Water Fluoridation Basics Over 70 ... 2% of U.S. adults have some form of periodontal disease. In adults aged 65 and older, 70.1% ...

  14. Literacy and Health Disparities

    ERIC Educational Resources Information Center

    Prins, Esther; Mooney, Angela

    2014-01-01

    This chapter explores the relationship between literacy and health disparities, focusing on the concept of health literacy. Recommendations are provided for ways to bridge the health literacy gap for learners in adult basic education and family literacy programs.

  15. Literacy and Health Disparities

    ERIC Educational Resources Information Center

    Prins, Esther; Mooney, Angela

    2014-01-01

    This chapter explores the relationship between literacy and health disparities, focusing on the concept of health literacy. Recommendations are provided for ways to bridge the health literacy gap for learners in adult basic education and family literacy programs.

  16. Air pollutants targeted by radiocarbon dating

    SciTech Connect

    Not Available

    1987-07-01

    Chemists at the Commerce Department's National Bureau of Standards (NBS) are answering questions about where certain atmospheric contaminants originate by refining a method best known for determining the age of archeological objects. Called radiocarbon dating, the method allows NBS scientists to examine air samples and determine whether contaminants come from naturally occurring or manmade sources-or a combination of the two. Making these distinctions is important to federal and state environmental agencies, which identify industrial sources of pollution for regulatory action. An overbalance of atmospheric carbon can cause a number of environmental problems. In methane's case, high levels are of concern to environmental agencies because of greenhouse properties. Methane also has been implicated as a possible contributor to changes in the ozone layer that protects the Earth from excessive ultraviolet light. Levels of methane have been increasing at an annual rate of about one percent over the last decade. This has caused concern in the environmental community, which hopes to determine just where the elevated levels are coming from. The NBS research is aimed at definitively pinpointing sources of methane and other atmospheric contaminants.

  17. Radiocarbon: nature's tracer for carbonaceous pollutants

    SciTech Connect

    Currie, L.A.; Klouda, G.A.; Gerlach, R.W.

    1982-01-01

    Recent developments in radiocarbon dating techniques have made it feasible to determine /sup 14/C//sup 12/C ratios in samples containing milligram or even microgram quantities of carbon. As a result, it has become practicable to apply these techniques to the study of trace gases and particles in the atmosphere, as a means of resolving anthropogenic from natural source components. Interpretation of /sup 14/C data is straightforward: biospheric carbon (such as vegetation) is alive with a /sup 14/C//sup 12/C ratio of about 1.5 x 10 to the 12th power, whereas fossil carbon is dead. Beyond this dichotomous classification it becomes very interesting to combine the isotopic data with concurrent chemical data, as well as spatial and temporal distributions, in order to infer the strengths of specific sources of carbonaceous pollutants. A brief review will be presented of program on atmospheric gases and carbonaceous particles. For the latter, the authors have assayed individual chemical and size fractions, and samples collected in urban, rural, and remote locales. The biogenic carbon fraction -- presumably from wood-burning -- ranged from 10 to 100% for the urban samples analyzed.

  18. Disparities in Underserved White Populations: The Case of Cancer-Related Disparities in Appalachia

    PubMed Central

    Paskett, Electra D.; Lengerich, Eugene J.; Schoenberg, Nancy E.; Kennedy, Stephenie K.; Conn, Mary Ellen; Roberto, Karen A.; Dwyer, Sharon K.; Fickle, Darla; Dignan, Mark

    2011-01-01

    There are meaningful cancer-related disparities in the Appalachian region of the U.S. To address these disparities, the Appalachia Community Cancer Network (ACCN), a collaboration of investigators and community partners in five states (Kentucky, Ohio, Pennsylvania, Virginia, and West Virginia), is involved in increasing cancer education and awareness, conducting community-based participatory research (CBPR), and creating mentorship and training opportunities. The primary objective of this paper is to describe cancer-related disparities in the Appalachian region of the U.S. as an example of the disparities experienced by underserved, predominantly white, rural populations, and to describe ACCN activities designed to intervene regarding these disparities. An ACCN overview/history and the diverse activities of ACCN-participating states are presented in an effort to suggest potential useful strategies for working to reduce health-related disparities in underserved white populations. Strengths that have emerged from the ACCN approach (e.g., innovative collaborations, long-standing established networks) and remaining challenges (e.g., difficulties with continually changing communities, scarce resources) are described. Important recommendations that have emerged from the ACCN are also presented, including the value of allowing communities to lead CBPR efforts. Characteristics of the community-based work of the ACCN provide a framework for reducing health-related disparities in Appalachia and in other underserved white and rural populations. PMID:21873582

  19. Engendering health disparities.

    PubMed

    Spitzer, Denise L

    2005-01-01

    How is gender implicated in our exploration of health disparities in Canada? Set against the backdrop of federal government policy, this review paper examines the ways in which gender intersects with other health determinants to produce disparate health outcomes. An overview of salient issues including the impact of gender roles, environmental exposures, gender violence, workplace hazards, economic disparities, the costs of poverty, social marginalization and racism, aging, health conditions, interactions with health services, and health behaviours are considered. This review suggests health is detrimentally affected by gender roles and statuses as they intersect with economic disparities, cultural, sexual, physical and historical marginalization as well as the strains of domestic and paid labour. These conditions result in an unfair health burden borne in particular by women whose access to health determinants is--in various degrees--limited. While progress has certainly been made on some fronts, the persistence of health disparities among diverse populations of women and men suggests a postponement of the vision of a just society with health for all that was articulated in the Federal Plan on Gender Equality. Commitment, creativity and collaboration from stakeholders ranging from various levels of government, communities, academics, non-governmental agencies and health professionals will be required to reduce and eliminate health disparities between and among all members of our society.

  20. The absolute disparity anomaly and the mechanism of relative disparities

    PubMed Central

    Chopin, Adrien; Levi, Dennis; Knill, David; Bavelier, Daphne

    2016-01-01

    There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's absolute disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different absolute and relative disparities. Participants were asked to judge the depth of two lines presented at the same distance from the fixation plane (absolute disparity) or the depth between two lines presented at different distances (relative disparity). We used a single stimulus method involving a unique memory component for both conditions, and no extraneous references were available. We also measured vergence noise using Nonius lines. Stereo thresholds were substantially worse for absolute disparities than for relative disparities, and the difference could not be explained by vergence noise. We attribute this difference to an absence of conscious readout of absolute disparities, termed the absolute disparity anomaly. We further show that the pattern of correlations between vergence noise and absolute and relative disparity acuities can be explained jointly by the existence of the absolute disparity anomaly and by the assumption that relative disparity information is computed from absolute disparities (Hypothesis 1). PMID:27248566

  1. High-precision radiocarbon dating and historical biblical archaeology in southern Jordan

    PubMed Central

    Levy, Thomas E.; Higham, Thomas; Bronk Ramsey, Christopher; Smith, Neil G.; Ben-Yosef, Erez; Robinson, Mark; Münger, Stefan; Knabb, Kyle; Schulze, Jürgen P.; Najjar, Mohammad; Tauxe, Lisa

    2008-01-01

    Recent excavations and high-precision radiocarbon dating from the largest Iron Age (IA, ca. 1200–500 BCE) copper production center in the southern Levant demonstrate major smelting activities in the region of biblical Edom (southern Jordan) during the 10th and 9th centuries BCE. Stratified radiocarbon samples and artifacts were recorded with precise digital surveying tools linked to a geographic information system developed to control on-site spatial analyses of archaeological finds and model data with innovative visualization tools. The new radiocarbon dates push back by 2 centuries the accepted IA chronology of Edom. Data from Khirbat en-Nahas, and the nearby site of Rujm Hamra Ifdan, demonstrate the centrality of industrial-scale metal production during those centuries traditionally linked closely to political events in Edom's 10th century BCE neighbor ancient Israel. Consequently, the rise of IA Edom is linked to the power vacuum created by the collapse of Late Bronze Age (LB, ca. 1300 BCE) civilizations and the disintegration of the LB Cypriot copper monopoly that dominated the eastern Mediterranean. The methodologies applied to the historical IA archaeology of the Levant have implications for other parts of the world where sacred and historical texts interface with the material record. PMID:18955702

  2. High-precision radiocarbon dating and historical biblical archaeology in southern Jordan.

    PubMed

    Levy, Thomas E; Higham, Thomas; Bronk Ramsey, Christopher; Smith, Neil G; Ben-Yosef, Erez; Robinson, Mark; Münger, Stefan; Knabb, Kyle; Schulze, Jürgen P; Najjar, Mohammad; Tauxe, Lisa

    2008-10-28

    Recent excavations and high-precision radiocarbon dating from the largest Iron Age (IA, ca. 1200-500 BCE) copper production center in the southern Levant demonstrate major smelting activities in the region of biblical Edom (southern Jordan) during the 10th and 9th centuries BCE. Stratified radiocarbon samples and artifacts were recorded with precise digital surveying tools linked to a geographic information system developed to control on-site spatial analyses of archaeological finds and model data with innovative visualization tools. The new radiocarbon dates push back by 2 centuries the accepted IA chronology of Edom. Data from Khirbat en-Nahas, and the nearby site of Rujm Hamra Ifdan, demonstrate the centrality of industrial-scale metal production during those centuries traditionally linked closely to political events in Edom's 10th century BCE neighbor ancient Israel. Consequently, the rise of IA Edom is linked to the power vacuum created by the collapse of Late Bronze Age (LB, ca. 1300 BCE) civilizations and the disintegration of the LB Cypriot copper monopoly that dominated the eastern Mediterranean. The methodologies applied to the historical IA archaeology of the Levant have implications for other parts of the world where sacred and historical texts interface with the material record.

  3. A radiocarbon-dated cave sequence and the Pleistocene/Holocene transition in Hungary

    NASA Astrophysics Data System (ADS)

    Sümegi, Pál; Náfrádi, Katalin

    2015-11-01

    The Petény Cave located on the Hungarian Highlands yielded one of the most well-documented vertebrate fauna of the Late Pleistocene and Holocene in Hungary. In addition to the vertebrate remains, considerable numbers of mollusc shells and charcoals were retrieved from the profile of the rock shelter. Furthermore, a pollen sequence close to the cavewas also evaluated in order to reconstruct the flora of the region. A new radiocarbon analysis of samples from the Petény Cave was used to correlate data of different methods and to correct the earlier outcomes. The cave sequence exposes layers from 15.180 cal BP to 483 cal BP. Nevertheless, based on our new radiocarbon data, the sequence is incomplete and layers corresponding to the Pleistocene/Holocene boundary are missing from the profile. The results of our radiocarbon analysis clearly support considerable amounts of thermo-mesophylous gastropod species appearing as early as 15.180 cal BP. The appearance of deciduous woodlands in the Carpathian Basin along with the concomitant mollusc elements is much earlier than previously assumed, supporting the presence of temperate woodland refugia in the study area.

  4. Si-Traceable Scale for Measurements of Radiocarbon Concentration

    NASA Astrophysics Data System (ADS)

    Hodges, Joseph T.; Fleisher, Adam J.; Liu, Qingnan; Long, David A.

    2017-06-01

    Radiocarbon (^{14}C) dating of organic materials is based on measuring the ^{14}C/^{12}C atomic fraction relative to the nascent value that existed when the material was formed by photosynthetic conversion of carbon dioxide present in the atmosphere. This field of measurement has numerous applications including source apportionment of anthropogenic and biogenic fuels and combustion emissions, carbon cycle dynamics, archaeology, and forensics. Accelerator mass spectrometry (AMS) is the most widely used method for radiocarbon detection because it can measure extremely small amounts of radiocarbon (background of nominally 1.2 parts-per-trillion) with high relative precision (0.4 %). AMS measurements of radiocarbon are typically calibrated by reference to standard oxalic-acid (C_2H_2O_4) samples of known radiocativity that are derived from plant matter. Specifically, the internationally accepted absolute dating reference for so-called "modern-equivalent" radiocarbon is 95 % of the specific radioactivity in AD 1950 of the National Bureau of Standards (NBS) oxalic acid standard reference material and normalized to δ^{13}C_{VPDB} = 19 per mil. With this definition, a "modern-equivalent" corresponds to 1.176(70) parts-per-trillion of ^{14}C relative to total carbon content. As an alternative radiocarbon scale, we propose an SI-traceable method to determine ^{14}C absolute concentration which is based on linear Beer-Lambert-law absorption measurements of selected ^{14}C^{16}O_2 ν_3-band line areas. This approach is attractive because line intensities of chosen radiocarbon dioxide transitions can be determined by ab initio calculations with relative uncertainties below 0.5 %. This assumption is justified by the excellent agreement between theoretical values of line intensities and measurements for stable isotopologues of CO_2. In the case of cavity ring-down spectroscopy (CRDS) measurements of ^{14}C^{16}O_2 peak areas, we show that absolute, SI-traceable concentrations of

  5. Are disparities of waiting times for breast cancer care related to socio-economic factors? A regional population-based study (France).

    PubMed

    Ayrault-Piault, Stéphanie; Grosclaude, Pascale; Daubisse-Marliac, Laetitia; Pascal, Jean; Leux, Christophe; Fournier, Evelyne; Tagri, Anne-Delphine; Métais, Magali; Lombrail, Pierre; Woronoff, Anne-Sophie; Molinié, Florence

    2016-11-01

    The increasing number of breast cancer cases may induce longer waiting times (WT), which can be a source of anxiety for patients and may play a role in survival. The aim of this study was to examine the factors, in particular socio-economic factors, related to treatment delays. Using French Cancer Registry databases and self-administered questionnaires, we included 1,152 women with invasive non-metastatic breast cancer diagnosed in 2007. Poisson regression analysis was used to identify WTs' influencing factors. For 973 women who had a malignant tissue sampling, the median of overall WT between the first imaging procedure and the first treatment was 44 days (9 days for pathological diagnostic WT and 31 days for treatment WT). The medical factors mostly explained inequalities in WTs. Socio-economic and behavioral factors had a limited impact on WTs except for social support which appeared to be a key point. Better identifying the factors associated with increase in WTs will make it possible to develop further interventional or prospective studies to confirm their causal role in delay and at last reduce disparities in breast cancer management.

  6. Characterization of Arctic elemental carbon in Barrow, AK using radiocarbon source apportionment

    NASA Astrophysics Data System (ADS)

    Barrett, T. E.; Usenko, S.; Robinson, E. M.; Sheesley, R. J.

    2013-12-01

    Currently, the Arctic is one of the fastest warming regions on earth with surface temperatures increasing at a rate nearly double the global mean over recent decades. Despite the fact that atmospheric concentrations of elemental carbon (EC) are lower in the Arctic than in lower latitudes, deposition of EC on snow and ice may exacerbate regional warming by simultaneously decreasing albedo and increasing melt rates. Due to the intensifying Arctic oil exploration in areas such as the Beaufort and Chukchi seas, the impact of new emission sources such as heavy fuel and heavy diesel combustion on regional carbon needs to be assessed. The first step in developing mitigation strategies for reducing current and future EC emissions in the Arctic is to determine emission source contributions. This study aims to determine the relative contributions of fossil fuel and biomass combustion and to identify major source regions of EC to the Arctic. Radiocarbon analysis of both total organic carbon (TOC) and EC combined with organic tracer and back trajectory analysis has been applied to a set of wintertime coarse particulate matter (PM10) samples from Barrow, AK. Preliminary apportionment for January 2013 indicates roughly half of TOC is from biogenic/biomass burning emissions and one third of EC is due to biomass burning emissions. The radiocarbon results will be combined with organic tracer analysis (polycyclic aromatic hydrocarbons, petroleum biomarkers and normal alkanes), increasing the specificity of the relative contribution of both the fossil and modern (biogenic/biomass burning) carbon emission sources. This research represents the first reported radiocarbon values for Arctic EC, providing highly conclusive source apportionment prior to the influence of increased drilling operations and ship traffic in the Beaufort and Chukchi seas.

  7. Summarizing Social Disparities in Health

    PubMed Central

    Asada, Yukiko; Yoshida, Yoko; Whipp, Alyce M

    2013-01-01

    Context Reporting on health disparities is fundamental for meeting the goal of reducing health disparities. One often overlooked challenge is determining the best way to report those disparities associated with multiple attributes such as income, education, sex, and race/ethnicity. This article proposes an analytical approach to summarizing social disparities in health, and we demonstrate its empirical application by comparing the degrees and patterns of health disparities in all fifty states and the District of Columbia (DC). Methods We used the 2009 American Community Survey, and our measure of health was functional limitation. For each state and DC, we calculated the overall disparity and attribute-specific disparities for income, education, sex, and race/ethnicity in functional limitation. Along with the state rankings of these health disparities, we developed health disparity profiles according to the attribute making the largest contribution to overall disparity in each state. Findings Our results show a general lack of consistency in the rankings of overall and attribute-specific disparities in functional limitation across the states. Wyoming has the smallest overall disparity and West Virginia the largest. In each of the four attribute-specific health disparity rankings, however, most of the best- and worst-performing states in regard to overall health disparity are not consistently good or bad. Our analysis suggests the following three disparity profiles across states: (1) the largest contribution from race/ethnicity (thirty-four states), (2) roughly equal contributions of race/ethnicity and socioeconomic factor(s) (ten states), and (3) the largest contribution from socioeconomic factor(s) (seven states). Conclusions Our proposed approach offers policy-relevant health disparity information in a comparable and interpretable manner, and currently publicly available data support its application. We hope this approach will spark discussion regarding how best

  8. A calendar chronology for Pleistocene mammoth and horse extinction in North America based on Bayesian radiocarbon calibration

    NASA Astrophysics Data System (ADS)

    Buck, Caitlin E.; Bard, Edouard

    2007-09-01

    Recent debate about the timing of late Pleistocene extinctions in North America has taken place on the radiocarbon timescale. Since the current internationally agreed radiocarbon calibration curve (known as IntCal04) extends back well into the Pleistocene, it is possible to make inferences on the calendar scale. To do so requires some fairly sophisticated, tailored statistical tools, to allow for (a) the presence of considerable uncertainty on individual radiocarbon ages and on the IntCal04 estimate, and (b) the inevitable incompleteness of our access to the fossil record. In this paper we demonstrate Bayesian radiocarbon calibration software, known as BCal, which implements models with both of these features, is tried and tested within the archaeology research community, but has not previously been used by those engaged in extinction research. We conclude that the extinction of horse ( Equus ferus/caballus) in Alaska and Yukon is broadly contemporary with the arrival of humans in the area and took place at around 14,200 cal BP. We find that the extinction of mammoth ( Mammuthus primigenius) in the same region occurred around 900 calendar years later (c. 13,300 cal BP). We also establish, with high probability, that the start of the Bölling warm phase occurred before these events and that the start of the Younger Dryas cold phase occurred after.

  9. Preparation of bone samples in the Gliwice Radiocarbon Laboratory for AMS radiocarbon dating.

    PubMed

    Piotrowska, N; Goslar, T

    2002-12-01

    In the Gliwice Radiocarbon Laboratory, a system for preparation of samples for AMS dating has been built. At first it was used to produce graphite targets from plant macrofossils and sediments. In this study we extended its capabilities with the preparation of bones. We dealt with 3 methods; the first was the classical Longin method of collagen extraction, the second one included additional treatment of powdered bone in alkali solution, while in the third one carboxyl carbon was separated from amino acids obtained after hydrolysis of protein. The suitability of the methods was tested on 2 bone samples. Most of our samples gave ages > 40 kyr BP, suggesting good performance of the adapted methods, except for one sample prepared with simple Longin method. For routine preparation of bones we chose the Longin method with additional alkali treatment.

  10. Tracing tephra horizons in the Greenland ice-cores and the potential for integrating disparate proxy records in the North Atlantic region

    NASA Astrophysics Data System (ADS)

    Davies, S. M.; Abbott, P.; Bigler, M.; Cook, E.; Johnsen, S.; Seierstad, I.; Steffensen, J.; Svensson, A.; Pearce, N. J.; Wastegård, S.

    2011-12-01

    Although the millennial-scale climatic events that characterise the last glacial period are well-documented in a large number of disparate proxy records, the causal mechanisms remain poorly understood. Large dating uncertainties associated with conventional approaches severely limit the integration of these records to test the degree of climatic synchroneity in relation to these short-lived oscillations. One technique that has considerable potential for the synchronisation of different records is tephrochronology. Tephra isochrones displaying distinct geochemical fingerprints and deposited instantaneously following an eruption have the unique advantage of representing fixed time-lines between different proxy records. Here we report on the ongoing work to trace tephra horizons in the Greenland ice-cores (NGRIP and GRIP) that have the potential to enhance the synchronisation of records spanning the last glacial period. Several of the tephras identified coincide with rapid climatic jumps imprinted in the Greenland ice-cores and thus, represent independent constraints that hold considerable promise for assessing lead/lag responses between the Earth's climatic components. Major and trace element signatures are used to characterise these horizons and independent ice-core age estimates are presented which can be incorporated into building chronological models for other palaeoarchives in which common tephra horizons can be identified. We also present the latest results from the NEEM record whereby a new tephra screening approach coupled to the Continuous Flow Analysis set-up is adopted. This work falls within the objectives of the SMART (Synchronising MArine and Ice-core Records using Tephrochronology) and the TRACE (Tephra constraints on RApid Cimatic Events) projects.

  11. The distribution of bomb radiocarbon in the ocean

    NASA Astrophysics Data System (ADS)

    Broecker, Wallace S.; Peng, Tsung-Hung; Ostlund, Gote; Stuiver, Minze

    1985-01-01

    Water column inventories are calculated for bomb radiocarbon at all the stations occupied during the GEOSECS and NORPAX expeditions and for the available TTO stations. The pattern of global inventories obtained in this way suggests that a sizable portion of the bomb radiocarbon that entered the Antarctic, the northern Pacific, and the tropical ocean has been transported to the adjacent temperate zones. A strategy for utilizing these inventory anomalies as constraints on global ocean circulation models is presented. Essential to this strategy are the improvement of our knowledge of the pattern of wind speed over the ocean, the establishment of the wind speed dependence of the rate of gas exchange between the atmosphere and sea, and the continued mapping of the distribution of bomb-produced radiocarbon in the sea.

  12. Radiocarbon dating of medieval manuscripts from the University of Seville

    NASA Astrophysics Data System (ADS)

    Santos, F. J.; Gómez-Martínez, I.; García-León, M.

    2010-04-01

    Eleven samples (parchment and paper) from different medieval manuscripts belonging to the cultural heritage of the University of Seville have been radiocarbon dated on the 1 MV AMS facility at the CNA in Seville (Spain). The objective of this study is double. First of all, these are the first real "unknown" samples treated in the radiocarbon laboratory and dated on our AMS facility, SARA (Spanish Accelerator for Radionuclide Analysis). Besides, some useful information about the manuscripts can be obtained, either to corroborate the dates, or in some cases, to decide between possible dates. As expected, a general agreement is found between radiocarbon results and palaeographical data. Nevertheless, some interesting facts have been learned through this study. We present in this paper the procedure to prepare the samples and the ages obtained with a brief discussion of the results.

  13. Re-investigating the isotopic fractionation corrections in radiocarbon measurements

    NASA Astrophysics Data System (ADS)

    Fahrni, S.; Santos, G. M.; Xu, X.; Southon, J. R.

    2012-12-01

    By convention (Stuiver and Polach, 1977), 14C data has to be corrected for any isotopic fractionation occurring in nature, during the sample preparation or the measurement. The fractionation factor b = 2.0 used to correct the 14C/12C ratio for shifts in the 13C/12C ratio has been proposed in 1954 (Craig, 1954) and has been applied ever since. While theoretical considerations have suggested moderate deviations of b from 2.0, some measurements have suggested larger differences (e.g. Saliege and Fontes, 1984). With the increasing precision of radiocarbon measurements, potential deviations of b from 2.0 become more significant, since these could cause shifts of several decades in some radiocarbon dates (Southon, 2011). It is therefore of great interest for the radiocarbon community to re-evaluate the fractionation corrections. We present approaches for the experimental determination of b and discuss results and their effects on radiocarbon dating. Stuiver M., Polach H.A., 1977. Discussion: reporting of 14C data. Radiocarbon 19(3):355-63. Saliege J.F., Fontes J.C., 1984. Essai de détermination expérimentale du fractionnement des isotopes 13C et 14C du carbone au cours de processus naturels. International Journal of Applied Radiation and Isotopes 35(1):55-62. Craig H., 1954. Carbon 13 in plants and the relationships between carbon 13 and carbon 14 in nature. Journal of Geology 62(2):115-49. Southon J., 2011. Are the Fractionation Corrections Correct: Are the Isotopic Shifts for 14C/12C Ratios in Physical Processes and Chemical Reactions Really Twice Those for 13C/12C? Radiocarbon 53(4):691-704.

  14. Data Show Retention Disparities

    ERIC Educational Resources Information Center

    Adams, Caralee J.; Robelen, Erik W.; Shah, Nirvi

    2012-01-01

    New nationwide data collected by the U.S. Department of Education's civil rights office reveal stark racial and ethnic disparities in student retentions, with black and Hispanic students far more likely than white students to repeat a grade, especially in elementary and middle school. The contrast is especially strong for African-Americans. In the…

  15. Data Show Retention Disparities

    ERIC Educational Resources Information Center

    Adams, Caralee J.; Robelen, Erik W.; Shah, Nirvi

    2012-01-01

    New nationwide data collected by the U.S. Department of Education's civil rights office reveal stark racial and ethnic disparities in student retentions, with black and Hispanic students far more likely than white students to repeat a grade, especially in elementary and middle school. The contrast is especially strong for African-Americans. In the…

  16. Radiocarbon dating the appearance of modern humans and timing of cultural innovations in Europe: new results and new challenges.

    PubMed

    Conard, Nicholas J; Bolus, Michael

    2003-03-01

    New radiocarbon dates from the sites of Bockstein-Törle, Geissenklösterle, Hohle Fels, Hohlenstein-Stadel, Sirgenstein, and Vogelherd in the Swabian Jura of southwestern Germany indicate that the Aurignacian of the region spans the period from ca. 40-30ka BP. If the situation at Vogelherd, in which skeletal remains from modern humans underlie an entire Aurignacian sequence, is viewed as representative for the region, the dates from the Swabian Jura support the hypothesis that populations of modern humans entered the region by way of the "Danube Corridor." The lithic technology from the lower Aurignacian of Geissenklösterle III is fully developed, and classic Aurignacian forms are well represented. During the course of the Aurignacian, numerous assemblages rich in art works, jewelry, and musical instruments are documented. By no later than 29ka BP the Gravettian was well established in the region. These dates are consistent with the "Kulturpumpe" hypothesis that important cultural innovations of the Aurignacian and Gravettian in Swabia predate similar developments in other regions of Europe. The radiocarbon dates from Geissenklösterle corroborate observations from other non-archaeological data sets indicating large global fluctuations in the atmospheric concentrations of radiocarbon between 30 and 50ka calendar years ago. These fluctuations lead to complications in building reliable chronologies during this period and cause the "Middle Paleolithic Dating Anomaly" and the "Coexistence Effect," which tend to exaggerate the temporal overlap between Neanderthals and modern humans.

  17. Source apportionment of atmospheric aliphatic and polycyclic aromatic hydrocarbons using compound-specific radiocarbon analysis

    NASA Astrophysics Data System (ADS)

    Gustafsson, Ö.; Mandalakis, M.; Zencak, Z.; Sheesley, R.; Kruså, M.

    2009-04-01

    Recent development in compound-specific radiocarbon analysis (CSRA) now allows application of this analytical dimension toward source apportionment of natural and anthropogenic compounds in the atmosphere. CSRA studies of semi-volatile n-alkanes and polycyclic aromatic hydrocarbons (PAHs) in air collected at various locations throughout Europe combine to reveal both inter-compound, inter-regional and inter-seasonal variations in sources. For instance, modern biogenic sources contribute a significant portion (frequently up to 50%) of the atmospheric load of priority pollutant PAHs and long-chained n-alkanes, suggesting that such sources should be scrutinized for effective reduction.

  18. Mediterranean Sea surface radiocarbon reservoir age changes since the last glacial maximum.

    PubMed

    Siani, G; Paterne, M; Michel, E; Sulpizio, R; Sbrana, A; Arnold, M; Haddad, G

    2001-11-30

    Sea surface reservoir ages must be known to establish a common chronological framework for marine, continental, and cryospheric paleoproxies, and are crucial for understanding ocean-continent climatic relationships and the paleoventilation of the ocean. Radiocarbon dates of planktonic foraminifera and tephra contemporaneously deposited over Mediterranean marine and terrestrial regions reveal that the reservoir ages were similar to the modern one (approximately 400 years) during most of the past 18,000 carbon-14 years. However, reservoir ages increased by a factor of 2 at the beginning of the last deglaciation. This is attributed to changes of the North Atlantic thermohaline circulation during the massive ice discharge event Heinrich 1.

  19. Evaluating the Paleoindian Radiocarbon Record at the Onset of the Younger Dryas: Sensitivity Analyses and Bayesian Chronology-Building

    NASA Astrophysics Data System (ADS)

    Culleton, B. J.; Kennett, D. J.

    2008-12-01

    The onset of the Younger Dryas (13.0-12.9 ka) in North America is marked in the archaeological record by the transition from Clovis to Folsom cultural assemblages, as well as the extinction of many megafauna species. The nature of the transition-gradual or abrupt, continuous or discontinuous, regionally uniform or variable - remains poorly understood because of: 1) low-precision and low-quality radiocarbon records; 2) concerns about the accuracy of the calibration curve before ca. 12.4 ka; and, 3) disagreement on the appropriate statistical models for chronology building. Here we evaluate two approaches to Paleoindian radiocarbon chronology, summed probability distributions and Bayesian phase/boundary models. Summed probability frequencies have been used as demographic proxies recently, but the effects of sample quality, density, and the variations in the calibration curve are largely unexplored. Sensitivity analyses were done by simulating radiocarbon ages at 10, 25, 50 and 100 cal yr intervals with varying measurement errors, which were calibrated and summed to obtain a probability distribution function for each run. We find that dense, high-precision radiocarbon records are necessary to detect gaps as small as 100 years in the record. Currently available radiocarbon databases for the Paleoindian period can at best be characterized as sparse and of low- to medium-precision, arguing against the use of summed probabilities as a proxy for human activity during that period. Bayesian statistical models incorporate a priori archaeological information (e.g., stratigraphic relationships, cultural assemblage) to constrain calibrated radiocarbon ages leading to more refined chronologies. Selected high-precision, reliable radiocarbon dates were used to build phase and boundary models for Clovis and post-Clovis periods, and to determine the likelihood of a gap between them consistent with depopulation consistent with an ET impact at the Younger Dryas boundary. Model results

  20. Bomb radiocarbon in metabolically inert tissues from terrestrial and marine mammals

    SciTech Connect

    Bada, J.L.; Vrolijk, C.D.; Brown, S.; Druffel, E.R.M.; Hedges, R.E.M.

    1987-10-01

    We report here radiocarbon measurements of monkey eye lens nucleus proteins and a narwhal tusk, biological tissues which have sampled the bomb radiocarbon signal in different ways. The results confirm the metabolic inertness of eye lens nucleus proteins and demonstrate the feasibility of measuring radiocarbon in small samples of biological tissue using accelerator mass spectrometry (AMS). The narwhal tusk provides a unique record of the radiocarbon activity in Arctic Ocean waters over most of the 20th century.

  1. Cancer Disparities: Unmet Challenges in the Elimination of Disparities

    PubMed Central

    Gehlert, Sarah; Colditz, Graham A.

    2012-01-01

    Background The first 20 years of publication of Cancer Epidemiology, Biomarkers & Prevention occurred during a period of increased attention to health disparities and advances in knowledge about their determinants. Yet, despite clear documentation of disparities and advanced understanding of determinants, we have made little headway in reducing disparities at the population level. Multilevel models, such as one produced by the Centers for Population Health and Health Disparities (CPHHD), hold promise for understanding the complex determinants of cancer disparities and their interactions as well as translating scientific discoveries into solutions. The CPHHD model maps across a range of scientific disciplines, from the biological to the social, each with its own disciplinary language and methods. The ability to work effectively across disciplinary boundaries is essential to framing comprehensive solutions. Methods After briefly characterizing the current state of knowledge about health disparities, we outline three major challenges faced by disparities researchers and practitioners and offer suggestions for addressing these challenges. Results These challenges are how to consider race and ethnicity in disparities research, how best to translate discoveries into public health solutions to cancer disparities, and how to create a research environment that supports the successful execution of multilevel research. Conclusions Attention to all three of the challenges outlined above is urgently needed to advance our efforts to eliminate cancer disparities. Impact Addressing the challenges outlined above will help to eliminate disparities in the future. PMID:21784956

  2. Rewriting the Central European Early Bronze Age Chronology: Evidence from Large-Scale Radiocarbon Dating.

    PubMed

    Stockhammer, Philipp W; Massy, Ken; Knipper, Corina; Friedrich, Ronny; Kromer, Bernd; Lindauer, Susanne; Radosavljević, Jelena; Wittenborn, Fabian; Krause, Johannes

    2015-01-01

    The transition from the Neolithic to the Early Bronze Age in Central Europe has often been considered as a supra-regional uniform process, which led to the growing mastery of the new bronze technology. Since the 1920s, archaeologists have divided the Early Bronze Age into two chronological phases (Bronze A1 and A2), which were also seen as stages of technical progress. On the basis of the early radiocarbon dates from the cemetery of Singen, southern Germany, the beginning of the Early Bronze Age in Central Europe was originally dated around 2300/2200 BC and the transition to more complex casting techniques (i.e., Bronze A2) around 2000 BC. On the basis of 140 newly radiocarbon dated human remains from Final Neolithic, Early and Middle Bronze Age cemeteries south of Augsburg (Bavaria) and a re-dating of ten graves from the cemetery of Singen, we propose a significantly different dating range, which forces us to re-think the traditional relative and absolute chronologies as well as the narrative of technical development. We are now able to date the beginning of the Early Bronze Age to around 2150 BC and its end to around 1700 BC. Moreover, there is no transition between Bronze (Bz) A1 and Bronze (Bz) A2, but a complete overlap between the type objects of the two phases from 1900-1700 BC. We thus present a revised chronology of the assumed diagnostic type objects of the Early Bronze Age and recommend a radiocarbon-based view on the development of the material culture. Finally, we propose that the traditional phases Bz A1 and Bz A2 do not represent a chronological sequence, but regionally different social phenomena connected to the willingness of local actors to appropriate the new bronze technology.

  3. Rewriting the Central European Early Bronze Age Chronology: Evidence from Large-Scale Radiocarbon Dating

    PubMed Central

    Knipper, Corina; Friedrich, Ronny; Kromer, Bernd; Lindauer, Susanne; Radosavljević, Jelena; Wittenborn, Fabian; Krause, Johannes

    2015-01-01

    The transition from the Neolithic to the Early Bronze Age in Central Europe has often been considered as a supra-regional uniform process, which led to the growing mastery of the new bronze technology. Since the 1920s, archaeologists have divided the Early Bronze Age into two chronological phases (Bronze A1 and A2), which were also seen as stages of technical progress. On the basis of the early radiocarbon dates from the cemetery of Singen, southern Germany, the beginning of the Early Bronze Age in Central Europe was originally dated around 2300/2200 BC and the transition to more complex casting techniques (i.e., Bronze A2) around 2000 BC. On the basis of 140 newly radiocarbon dated human remains from Final Neolithic, Early and Middle Bronze Age cemeteries south of Augsburg (Bavaria) and a re-dating of ten graves from the cemetery of Singen, we propose a significantly different dating range, which forces us to re-think the traditional relative and absolute chronologies as well as the narrative of technical development. We are now able to date the beginning of the Early Bronze Age to around 2150 BC and its end to around 1700 BC. Moreover, there is no transition between Bronze (Bz) A1 and Bronze (Bz) A2, but a complete overlap between the type objects of the two phases from 1900–1700 BC. We thus present a revised chronology of the assumed diagnostic type objects of the Early Bronze Age and recommend a radiocarbon-based view on the development of the material culture. Finally, we propose that the traditional phases Bz A1 and Bz A2 do not represent a chronological sequence, but regionally different social phenomena connected to the willingness of local actors to appropriate the new bronze technology. PMID:26488413

  4. Southern Ocean Carbon Sink Constraints from Radiocarbon in Drake Passage Air

    NASA Astrophysics Data System (ADS)

    Lindsay, C. M.; Lehman, S.; Miller, J. B.

    2014-12-01

    The Southern Ocean is one of the earth's largest regional net carbon sinks due to strong westerly winds, which drive surface gas exchange, deep mixing and upwelling. The strength of the sink is set by complex interactions between the physical circulation, gas exchange and biological activity in surface waters. Recent work by others has predicted that global warming may weaken the sink by strengthening the regional winds, increasing upwelling and the flux of deep, naturally carbon-rich and radiocarbon-depleted water into the surface mixed layer. The resulting decrease in the air-sea pCO2 gradient is thought to overwhelm other compensating changes, causing a weakened net sink. Here we demonstrate the use of precise measurements of radiocarbon in Drake Passage air (14CO2) to detect short-term fluctuations in the Southern Ocean gross sea-to-air C flux, and by extension, possible changes in the net carbon sink and their underlying causes. Drake Passage boundary layer air has been sampled since 2006 at roughly fortnightly intervals as part of NOAA's Cooperative Air Sampling Network, resulting in a 5-year high-resolution 14CO2 time-series with accompanying same-flask CO2 concentration measurements. Atmospheric measurements at Drake Passage are representative of zonal average exchange fluxes due to strong mixing by the westerly winds. In preliminary results, anomalously low ∆14C values are correlated with positive states of the Southern Annular Mode, a hemispheric-scale indicator of stronger westerly winds in the high latitude Southern Ocean. Simulations from the TM5 atmospheric transport model with a detailed global radiocarbon budget are used to interpret the results. These results appear to support the hypothesized link between stronger westerly winds and a weaker Southern Ocean carbon sink.

  5. VOC RADIOCARBON MEASUREMENTS DURING SCOS97 AND EMISSIONS INVENTORY VALIDATION

    EPA Science Inventory

    Radiocarbon (14C) measurements provide an estimate of the fraction of carbon in a sample that is biogenic. In September 1997 during SCOS97 a series of 3-h canister samples of ambient air were collected at the Azusa air monitoring station during morning and afternoon periods. ...

  6. Radiocarbon dates from the Casa Grande. Final report

    SciTech Connect

    Andresen, J.M.

    1981-01-01

    This report suggests a very early Civano construction date for Casa Grande, Casa Grande Ruins National Monument, Arizona on the basis of C14 dates from fragments of two primary roof beams. The radiocarbon dates presented are seen as a positive contribution to an understanding of the history of Casa Grande.

  7. Annually resolved atmospheric radiocarbon records reconstructed from tree-rings

    NASA Astrophysics Data System (ADS)

    Wacker, Lukas; Bleicher, Niels; Büntgen, Ulf; Friedrich, Michael; Friedrich, Ronny; Diego Galván, Juan; Hajdas, Irka; Jull, Anthony John; Kromer, Bernd; Miyake, Fusa; Nievergelt, Daniel; Reinig, Frederick; Sookdeo, Adam; Synal, Hans-Arno; Tegel, Willy; Wesphal, Torsten

    2017-04-01

    The IntCal13 calibration curve is mainly based on data measured by decay counting with a resolution of 10 years. Thus high frequency changes like the 11-year solar cycles or cosmic ray events [1] are not visible, or at least not to their full extent. New accelerator mass spectrometry (AMS) systems today are capable of measuring at least as precisely as decay counters [2], with the advantage of using 1000 times less material. The low amount of material required enables more efficient sample preparation. Thus, an annually resolved re-measurement of the tree-ring based calibration curve can now be envisioned. We will demonstrate with several examples the multitude of benefits resulting from annually resolved radiocarbon records from tree-rings. They will not only allow for more precise radiocarbon dating but also contain valuable new astrophysical information. The examples shown will additionally indicate that it can be critical to compare AMS measurements with a calibration curve that is mainly based on decay counting. We often see small offsets between the two measurement techniques, while the reason is yet unknown. [1] Miyake F, Nagaya K, Masuda K, Nakamura T. 2012. A signature of cosmic-ray increase in AD 774-775 from tree rings in Japan. Nature 486(7402):240-2. [2] Wacker L, Bonani G, Friedrich M, Hajdas I, Kromer B, Nemec M, Ruff M, Suter M, Synal H-A, Vockenhuber C. 2010. MICADAS: Routine and high-precision radiocarbon dating. Radiocarbon 52(2):252-62.

  8. Radiocarbon application in environmental science and archaeology in Croatia

    NASA Astrophysics Data System (ADS)

    Krajcar Bronić, I.; Obelić, B.; Horvatinčić, N.; Barešić, J.; Sironić, A.; Minichreiter, K.

    2010-07-01

    Radiocarbon is a cosmogenic radioisotope equally distributed throughout the troposphere and biosphere. This fact enables its most common application—radiocarbon dating. Natural equilibrium of radiocarbon has been disturbed by diverse anthropogenic activities during the last ˜150 years, enabling also the use of 14C in various environmental applications. Here we present three types of studies by using 14C that were performed in the Zagreb Radiocarbon Laboratory. 14C in atmospheric CO 2 has been monitored at several sites with various anthropogenic influences and the difference between the clean-air sites, the industrial city and the vicinity of a nuclear power plant has been established. 14C has been applied in geochronology of karst areas, especially in dating of tufa, speleothems and lake sediments, as well as in studies of geochemical carbon cycle. 14C has been used in various archaeological studies, among which the dating of the early Neolithic settlements in Croatia is presented. In these studies 14C was measured by radiometric techniques, i.e., by gas proportional counting and more recently by liquid scintillation counting (LSC). Two sample preparation techniques for LSC measurement were used: benzene synthesis for archaeological dating and other applications that require better precision, and direct absorption of CO 2 for monitoring purposes. The presented results show that various studies by using 14C can be successfully performed by the LSC technique, providing a large enough sample (>1 g of carbon).

  9. RADIOCARBON MEASUREMENTS ON PM-2.5 AMBIENT AEROSOL

    EPA Science Inventory

    Radiocarbon (14C) measurements provide an estimate of the fraction of carbon in a sample that is biogenic. The methodology has been extensively used in past wintertime studies to quantify the contribution of wood smoke to ambient aerosol. In summertime such measurements can p...

  10. RADIOCARBON ANALYSIS OF PM 2.5 AMBIENT AEROSOL

    EPA Science Inventory

    The radiocarbon (14C) content of an ambient aerosol sample can be directly related to the fraction of the sample's total carbon mass contributed by natural (biogenic) sources. Such knowledge is difficult to determine by other means, and important for devising ambient PM contro...

  11. RADIOCARBON ANALYSIS OF PM 2.5 AMBIENT AEROSOL

    EPA Science Inventory

    The radiocarbon (14C) content of an ambient aerosol sample can be directly related to the fraction of the sample's total carbon mass contributed by natural (biogenic) sources. Such knowledge is difficult to determine by other means, and important for devising ambient PM contro...

  12. VOC RADIOCARBON MEASUREMENTS DURING SCOS97 AND EMISSIONS INVENTORY VALIDATION

    EPA Science Inventory

    Radiocarbon (14C) measurements provide an estimate of the fraction of carbon in a sample that is biogenic. In September 1997 during SCOS97 a series of 3-h canister samples of ambient air were collected at the Azusa air monitoring station during morning and afternoon periods. ...

  13. Status of mass spectrometric radiocarbon detection at ETHZ

    NASA Astrophysics Data System (ADS)

    Seiler, Martin; Maxeiner, Sascha; Wacker, Lukas; Synal, Hans-Arno

    2015-10-01

    A prototype of a mass spectrometric radiocarbon detection instrument without accelerator stage was built for the first time and set into operation at ETH Zurich. The system is designed as an experimental platform to optimize performance of 14C detection at low ion energies and to study the most relevant processes that may limit system performance. The optimized stripper unit incorporates differential pumping to maintain a low gas outflow and a revised tube design to better match the phase space volume of the ion beam at low energies. The system is fully operational and has demonstrated true radiocarbon dating capabilities. The overall beam transmission through the stripper tube is about 40% for the 1+ charge state. Radiocarbon analyses with an overall precision of 0.6% were obtained on a single sample under regular measurement conditions. By analyzing multiple targets of the same sample material an uncertainty level of 0.3% has been reached. The background level corresponds to a radiocarbon age of 40,000 years.

  14. Radiocarbon dating in archaeology: Interdisciplinary aspects and consequences (an overview)

    NASA Astrophysics Data System (ADS)

    Palincaş, Nona

    2017-06-01

    This paper is an overview of recent developments in the radiocarbon dating of the most frequently analyzed archaeological materials - wood, short-lived plants, and human and animal bones - and draws attention to two sets of consequences. Firstly, while radiocarbon dating has become more accessible to archaeologists thanks to an increase in the number of laboratories, a lowering of prices, and a reduction in sample sizes, it has also grown far more dependent on fields of research, other than the traditional chemical pretreatment of samples and the physics involved in their measurement, such as wood anatomy and other fields of botany, stable isotope-based diet studies, geochemistry, micromorphology, statistics, etc., most of which are not easily accessible by the vast majority of users of radiocarbon dating (and sometimes not familiar to practicing archaeologists). Secondly, given that, on the one hand, there is still much scope for research in radiocarbon dating and, on the other, archaeological sites are a limited resource, there is need to create archives containing the detailed documentation of samples and, whenever possible, sample residues.

  15. Oceanic radiocarbon: Separation of the natural and bomb components

    NASA Astrophysics Data System (ADS)

    Broecker, Wallace S.; Sutherland, Stewart; Smethie, William; Peng, Tsung-Hung; Ostlund, Gote

    1995-06-01

    An improved method has been developed for the separation of the natural and bomb components of the radiocarbon in the ocean. The improvement involves the use of a very strong correlation between natural radiocarbon and dissolved silica. This method is applied to radiocarbon measurements made on samples collected during the Geochemical Ocean Sections Study (GEOSECS), Transient Tracers in the Ocean (TTO) and South Atlantic Ventilation Experiment (SAVE) expeditions. On the basis of this new separation we provide not only an estimate of the global inventory of bomb 14C at the time of the GEOSECS survey but also the distribution of bomb radiocarbon along four thermocline isopycnals in each ocean. We also document the evolution of the bomb 14C inventory and penetration along thermocline isopycnals in the North Atlantic Ocean between the times of the GEOSECS (1972-1973) and TTO (1980-1982) surveys and in the South Atlantic Ocean between the times of the GEOSECS (1973) and SAVE (1987-1989) surveys. In addition, we show that the bomb tritium to bomb 14C ratio (expressed in the tritium unit (TU) 81 units/100‰) for waters entering the thermocline of the northern hemisphere is about 9 times higher than for those entering the southern hemisphere thermocline. This contrast offers long-term potential as an indicator of inter-hemispheric transport of upper ocean waters.

  16. Geographical disparities of infant mortality in rural China

    PubMed Central

    Wang, Yanping; Zhu, Jun; He, Chunhua; Li, Xiaohong; Miao, Lei; Liang, Juan

    2012-01-01

    Objective The purpose of the study was to investigate the trends and causes of regional disparities of infant mortality rate (IMR) in rural China from 1996 to 2008. Design A population-based, longitudinal study. Setting The national child mortality surveillance network. Population Population of the 79 surveillance counties. Main outcome measure IMR, leading causes of infant death and the RR of IMR. Results The IMR in coastal, inland and remote regions declined by 72.4%, 62.9% and 58.2%, respectively, from 1996 to 2008. Compared with the coastal region, the RR of IMR were 1.7 (95% CI 1.6 to 1.9), 1.9 (95% CI 1.7 to 2.0) and 1.8 (95% CI 1.6 to 2.0) for inland region and 2.6 (95% CI 2.4 to 2.7), 3.2 (95% CI 3.0 to 3.5) and 3.1 (95% CI 2.7 to 3.4) for the remote region during 1996–2000, 2001–2005 and 2006–2008, respectively. The regional disparities existed for both male and female IMRs. The postneonatal mortality showed the highest regional disparities. Pneumonia, birth asphyxia, prematurity/low birth weight, injuries and diarrhoea were the main contributors to the regional disparities. There were significantly more infants who did not seek healthcare services before death in the remote region relative to the inland and coastal regions. Conclusion The results indicated persistent existence of regional disparities in IMR in rural China. It is worth noting that regional disparities in IMR increased in the remote and coastal regions during 2001–2005 in rural China. These disparities remained unchanged during 2006–2008. The results indicate that strategies to reduce mortality caused by pneumonia, birth asphyxia and diarrhoea are keys to reducing IMR. PMID:22247413

  17. Responses to interocular disparity correlation in the human cerebral cortex

    PubMed Central

    Ip, Ifan Betina; Minini, Loredana; Dow, James; Parker, Andrew J; Bridge, Holly

    2014-01-01

    Purpose Perceiving binocular depth relies on the ability of our visual system to precisely match corresponding features in the left and right eyes. Yet how the human brain extracts interocular disparity correlation is poorly understood. Methods We used functional magnetic resonance imaging (fMRI) to characterize brain regions involved in processing interocular disparity correlation. By varying the amount of interocular correlation of a disparity-defined random-dot-stereogram, we concomitantly controlled the perception of binocular depth and measured the percent Blood-Oxygenation-Level-Dependent (%BOLD)-signal in multiple regions-of-interest in the human occipital cortex and along the intra-parietal sulcus. Results A linear support vector machine classification analysis applied to cortical responses showed patterns of activation that represented different disparity correlation levels within regions-of-interest in the visual cortex. These also revealed a positive trend between the difference in disparity correlation and classification accuracy in V1, V3 and lateral occipital cortex. Classifier performance was significantly related to behavioural performance in dorsal visual area V3. Cortical responses to random-dot-stereogram stimuli were greater in the right compared to the left hemisphere. Conclusions Our results show that multiple regions in the cerebral cortex are sensitive to changes in interocular disparity correlation, and that dorsal area V3 may play an important role in the early transformation of binocular disparity to depth perception. PMID:24588533

  18. Genetic Research and Health Disparities

    PubMed Central

    Sankar, Pamela; Cho, Mildred K.; Condit, Celeste M.; Hunt, Linda M.; Koenig, Barbara; Marshall, Patricia; Lee, Sandra Soo-Jin; Spicer, Paul

    2008-01-01

    Alleviating health disparities in the United States is a goal with broad support. Medical research undertaken to achieve this goal typically adopts the well-established perspective that racial discrimination and poverty are the major contributors to unequal health status. However, the suggestion is increasingly made that genetic research also has a significant role to play in alleviating this problem, which likely overstates the importance of genetics as a factor in health disparities. Overemphasis on genetics as a major explanatory factor in health disparities could lead researchers to miss factors that contribute to disparities more substantially and may also reinforce racial stereotyping, which may contribute to disparities in the first place. Arguments that promote genetics research as a way to help alleviate health disparities are augmented by several factors, including research funding initiatives and the distinct demographic patterns of health disparities in the United States. PMID:15213210

  19. Diabetes Health Disparities

    PubMed Central

    Peek, Monica E.; Cargill, Algernon; Huang, Elbert S.

    2008-01-01

    Racial and ethnic minorities bear a disproportionate burden of the diabetes epidemic; they have higher prevalence rates, worse diabetes control, and higher rates of complications. This article reviews the effectiveness of health care interventions at improving health outcomes and/or reducing diabetes health disparities among racial/ethnic minorities with diabetes. Forty-two studies met inclusion criteria. On average, these health care interventions improved the quality of care for racial/ethnic minorities, improved health outcomes (such as diabetes control and reduced diabetes complications), and possibly reduced health disparities in quality of care. There is evidence supporting the use of interventions that target patients (primarily through culturally tailored programs), providers (especially through one-on-one feedback and education), and health systems (particularly with nurse case managers and nurse clinicians). More research is needed in the areas of racial/ethnic minorities other than African Americans and Latinos, health disparity reductions, long-term diabetes-related outcomes, and the sustainability of health care interventions over time. PMID:17881626

  20. Disparities of Trastuzumab Use in Resource-Limited or Resource-Abundant Regions and Its Survival Benefit on HER2 Positive Breast Cancer: A Real-World Study from China.

    PubMed

    Li, Jianbin; Wang, Shusen; Wang, Yongsheng; Wang, Xiaojia; Wang, Haibo; Feng, Jifeng; Zhang, Qingyuan; Sun, Tao; Ouyang, Quchang; Yin, Yongmei; Liu, Yinhua; Geng, Cuizhi; Yan, Min; Jiang, Zefei

    2017-08-10

    Trastuzumab is a key component of therapy for human epidermal growth receptor 2 (HER2) positive breast cancer. Because real-world data are lacking, the present research was conducted to evaluate the the actual use of and the effectiveness of trastuzumab in the real world in China. Inpatients with HER2 positive invasive breast cancer from 13 hospitals in Eastern China (2010-2015, n = 1,139) were included in this study. We aimed to assess the actual use of trastuzumab and to evaluate potential efficacy from trastuzumab in real-world research. Of 1,017 patients with early stage breast cancer (EBC), 40.5% (412/1,017) received trastuzumab therapy. Patients with EBC in resource-abundant regions (gross domestic product per capita >$15,000 and trastuzumab included in Medicare) are more likely to receive trastuzumab than those in resource-limited regions (37.3% vs. 13.0%, p < .05). After metastasis, 50.8% (366/720) patients received trastuzumab as their first-line therapy. More than 10% of patients with metastatic breast cancer (MBC) continued trastuzumab therapy after twice progression in resource-abundant regions, whereas more than 40% of patients never received any trastuzumab therapy during the whole course of therapy in resource-limited regions. Overall, the improvement in survival for trastuzumab versus non-trastuzumab was substantial in EBC (hazard ratio [HR] = 0.609, 95% confidence interval [CI]: 0.505-0.744) and in MBC (HR = 0.541, 95% CI: 0.418-0.606). This association was greater for patients with MBC who had never received trastuzumab (HR = 0.493, 95% CI: 0.372-0.576) than for those who had received adequate trastuzumab therapy in EBC stage (HR = 0.878, 95% CI: 0.506-1.431). This study showed great disparities in trastuzumab use in different regions and different treatment stages. Both EBC and MBC patients can benefit from trastuzumab, as the survival data show; however, when trastuzumab is adequate in the early stage, a further

  1. Divergent Radiocarbon Age Distributions of Carbon Pools in a Major Temperate River: Implications for Sources, Reactivity, and Land-Ocean Exchanges

    NASA Astrophysics Data System (ADS)

    Bauer, J. E.; Guo, L.; Perkey, D. W.; Raymond, P.; Bianchi, T. S.; Grottoli, A. G.; Matsui, Y.

    2011-12-01

    Rivers collectively transport carbon to the oceans in amounts comparable to other net global carbon fluxes. The characteristics of the carbon pools exported by major world rivers have largely been defined by studies of a single system - the Amazon - yet a significant fraction of global river water and material fluxes are driven by major temperate rivers which have received more limited study. We present new findings on the carbon pools of the Mississippi River system, which drains one of the most highly engineered drainage basins in the world. The three major pools (dissolved organic and inorganic C and particulate organic C; DOC, DIC and POC, respectively) have entirely disparate source-age characteristics, suggesting that each arises from unique reservoirs and/or processes in the Mississippi Basin. In particular, the radiocarbon (14C) contents of the organic matter pools indicate that river DOC arises from surface runoff of contemporary biomass, whereas POC originates from deeper soil horizons and/or protracted river bed erosion. Between the Upper Mississippi and the confluence of the Ohio River, concentrations of DOC and DIC along the mainstem of the river show non-conservative behavior. Downriver of the Ohio River confluence, however, DOC and DIC when corrected for tributary inputs remain essentially unchanged, suggesting the relative inertness of these pools over a significant length of the Mississippi. While a major part of the Mississippi and Ohio River watersheds is agricultural, carbon inputs from corn-dominated regions appear to be relatively limited. The export of carbon pools of highly divergent source-ages from the Mississippi and possibly other major temperate rivers indicates that terrestrial carbon losses from these systems may need to be reassessed in continent-scale and ocean carbon budgets.

  2. Poverty determinants of acute respiratory infections among Mapuche indigenous peoples in Chile's Ninth Region of Araucania, using GIS and spatial statistics to identify health disparities

    PubMed Central

    Rojas, Flavio

    2007-01-01

    Background This research concerns Araucanía, often called the Ninth Region, the poorest region of Chile where inequalities are most extreme. Araucanía hasn't enjoyed the economic success Chile achieved when the country returned to democracy in 1990. The Ninth Region also has the largest ethnic Mapuche population, located in rural areas and attached to small agricultural properties. Written and oral histories of diseases have been the most frequently used methods to explore the links between an ancestral population's perception of health conditions and their deprived environments. With census data and hospital records, it is now possible to incorporate statistical data about the links between poverty and disease among ethnic communities and compare results with non-Mapuche population. Data sources Hospital discharge records from Health Services North N = 24,126 patients, year 2003, and 7 hospitals), Health Services South (N = 81,780 patients and 25 hospitals); CAS-2/Family records (N = 527,539 individuals, 439 neighborhoods, 32 Comunas). Methods Given the over-dispersion of data and the clustered nature of observations, we used the global Moran's I and General G Gettis-Ord procedures to test spatial dependence. These tests confirmed the clusters of disease and the need to use spatial regression within a General Linear Mixed Model perspective. Results Health outcomes indicate significantly higher morbidity rates for the Mapuche compared to non-Mapuche in both age groups < 5 and 15–44, respectively; for the groups 70–79 and 80 + years of age, this trend is reversed. Mortality rates, however, are higher among Mapuches than non-Mapuches for the entire Ninth Region and for all age groups. Mortality caused by respiratory infections is higher among Mapuches than non-Mapuches in all age-groups. A major finding is the link between poverty and respiratory infections. Conclusion Poverty is significantly associated with respiratory infections in the population of Chile

  3. Poverty determinants of acute respiratory infections among Mapuche indigenous peoples in Chile's Ninth Region of Araucania, using GIS and spatial statistics to identify health disparities.

    PubMed

    Rojas, Flavio

    2007-07-02

    This research concerns Araucanía, often called the Ninth Region, the poorest region of Chile where inequalities are most extreme. Araucanía hasn't enjoyed the economic success Chile achieved when the country returned to democracy in 1990. The Ninth Region also has the largest ethnic Mapuche population, located in rural areas and attached to small agricultural properties. Written and oral histories of diseases have been the most frequently used methods to explore the links between an ancestral population's perception of health conditions and their deprived environments. With census data and hospital records, it is now possible to incorporate statistical data about the links between poverty and disease among ethnic communities and compare results with non-Mapuche population. Hospital discharge records from Health Services North N = 24,126 patients, year 2003, and 7 hospitals), Health Services South (N = 81,780 patients and 25 hospitals); CAS-2/Family records (N = 527,539 individuals, 439 neighborhoods, 32 Comunas). Given the over-dispersion of data and the clustered nature of observations, we used the global Moran's I and General G Gettis-Ord procedures to test spatial dependence. These tests confirmed the clusters of disease and the need to use spatial regression within a General Linear Mixed Model perspective. Health outcomes indicate significantly higher morbidity rates for the Mapuche compared to non-Mapuche in both age groups < 5 and 15-44, respectively; for the groups 70-79 and 80 + years of age, this trend is reversed. Mortality rates, however, are higher among Mapuches than non-Mapuches for the entire Ninth Region and for all age groups. Mortality caused by respiratory infections is higher among Mapuches than non-Mapuches in all age-groups. A major finding is the link between poverty and respiratory infections. Poverty is significantly associated with respiratory infections in the population of Chile's Ninth Region. High deprivation areas are associated

  4. Ocean science: Radiocarbon variability in the western North Atlantic during the last deglaciation

    USGS Publications Warehouse

    Robinson, L.F.; Adkins, J.F.; Keigwin, L.D.; Southon, J.; Fernandez, D.P.; Wang, S.-L.; Scheirer, D.S.

    2005-01-01

    We present a detailed history of glacial to Holocene radiocarbon in the deep western North Atlantic from deep-sea corals and paired benthic-planktonic foraminifera. The deglaciation is marked by switches between radiocarbon-enriched and -depleted waters, leading to large radiocarbon gradients in the water column. These changes played an important role in modulating atmospheric radiocarbon. The deep-ocean record supports the notion of a bipolar seesaw with increased Northern-source deep-water formation linked to Northern Hemisphere warming and the reverse. In contrast, the more frequent radiocarbon variations in the intermediate/deep ocean are associated with roughly synchronous changes at the poles.

  5. High-precision radiocarbon dating shows recent and rapid initial human colonization of East Polynesia.

    PubMed

    Wilmshurst, Janet M; Hunt, Terry L; Lipo, Carl P; Anderson, Atholl J

    2011-02-01

    The 15 archipelagos of East Polynesia, including New Zealand, Hawaii, and Rapa Nui, were the last habitable places on earth colonized by prehistoric humans. The timing and pattern of this colonization event has been poorly resolved, with chronologies varying by >1000 y, precluding understanding of cultural change and ecological impacts on these pristine ecosystems. In a meta-analysis of 1,434 radiocarbon dates from the region, reliable short-lived samples reveal that the colonization of East Polynesia occurred in two distinct phases: earliest in the Society Islands A.D. ∼1025-1120, four centuries later than previously assumed; then after 70-265 y, dispersal continued in one major pulse to all remaining islands A.D. ∼1190-1290. We show that previously supported longer chronologies have relied upon radiocarbon-dated materials with large sources of error, making them unsuitable for precise dating of recent events. Our empirically based and dramatically shortened chronology for the colonization of East Polynesia resolves longstanding paradoxes and offers a robust explanation for the remarkable uniformity of East Polynesian culture, human biology, and language. Models of human colonization, ecological change and historical linguistics for the region now require substantial revision.

  6. Changes in the radiocarbon reservoir age in Lake Xingyun, Southwestern China during the Holocene.

    PubMed

    Zhou, Aifeng; He, Yuxin; Wu, Duo; Zhang, Xiaonan; Zhang, Can; Liu, Zhonghui; Yu, Junqing

    2015-01-01

    Chronology is a necessary component of paleoclimatology. Radiocarbon dating plays a central role in determining the ages of geological samples younger than ca. 50 ka BP. However, there are many limitations for its application, including radiocarbon reservoir effects, which may cause incorrect chronology in many lakes. Here we demonstrate temporal changes in the radiocarbon reservoir age of Lake Xingyun, Southwestern China, where radiocarbon ages based on bulk organic matter have been reported in previous studies. Our new radiocarbon ages, determined from terrestrial plant macrofossils suggest that the radiocarbon reservoir age changed from 960 to 2200 years during the last 8500 cal a BP years. These changes to the reservoir effect were associated with inputs from either pre-aged organic carbon or 14C-depleted hard water in Lake Xingyun caused by hydrological change in the lake system. The radiocarbon reservoir age may in return be a good indicator for the carbon source in lake ecosystems and depositional environment.

  7. Changes in the Radiocarbon Reservoir Age in Lake Xingyun, Southwestern China during the Holocene

    PubMed Central

    Zhou, Aifeng; He, Yuxin; Wu, Duo; Zhang, Xiaonan; Zhang, Can; Liu, Zhonghui; Yu, Junqing

    2015-01-01

    Chronology is a necessary component of paleoclimatology. Radiocarbon dating plays a central role in determining the ages of geological samples younger than ca. 50 ka BP. However, there are many limitations for its application, including radiocarbon reservoir effects, which may cause incorrect chronology in many lakes. Here we demonstrate temporal changes in the radiocarbon reservoir age of Lake Xingyun, Southwestern China, where radiocarbon ages based on bulk organic matter have been reported in previous studies. Our new radiocarbon ages, determined from terrestrial plant macrofossils suggest that the radiocarbon reservoir age changed from 960 to 2200 years during the last 8500 cal a BP years. These changes to the reservoir effect were associated with inputs from either pre-aged organic carbon or 14C-depleted hard water in Lake Xingyun caused by hydrological change in the lake system. The radiocarbon reservoir age may in return be a good indicator for the carbon source in lake ecosystems and depositional environment. PMID:25815508

  8. Radiocarbon dating of marine material: mollusc versus foraminifera ages

    NASA Astrophysics Data System (ADS)

    Callard, L.; Long, A. J.; Plets, R. M.; Cooper, A.; Belknap, D. F.; Edwards, R.; Jackson, D.; Kelley, J. T.; Long, D.; Milne, G. A.; Monteys, X.; Quinn, R.

    2013-12-01

    A key challenge in reconstructing Quaternary environmental change from marine archives is developing a robust chronology. During the last ~50k a-1, radiocarbon dating is the mainstay for many studies. Often investigators are restricted in the material that is available for dating, with studies relying on AMS dating of either mono-specific or mixed assemblages of foraminifera. In some instances, marine molluscs (broken or whole, articulated or disarticulated) may also be present and can provide an alternative or complementary dating target. Previous radiocarbon dating of paired foraminiferal and marine molluscan samples from the Kattegat (Denmark) revealed significant age offsets between these materials, inferred to reflect greater reworking of foraminifera compared to the marine molluscs (Heier-Nielsen et al., 1995). Here we present the results of a comparable study from the Irish Sea Basin, which forms part of a wider investigation into the evidence for the Late Glacial sea-level minima at offshore sites from around Britain and Ireland. We have collected and AMS 14C-dated twelve paired samples of foraminifera and marine shells. The results shows a systematic age offset with the monospecific foraminifera samples consistently giving older ages than their shell counterparts. This offset increases with sample age, reaching a maximum offset of 3000 years in the oldest sample (~ 13 ka cal a BP). These results are consistent with the observations of Heier-Nielsen et al. (1995), and we hypothesize that foraminifera may be more susceptible to reworking from older deposits because of their lower effective density than the shell samples. However, foraminifera size and shape may also be contributing factors. These findings are potentially significant for studies that develop chronologies based on radiocarbon dating of foraminifera alone, since the resulting dates may over-estimate sample age by several thousand years. We conclude by outlining an experimental design that seeks

  9. Disparities in stroke incidence contributing to disparities in stroke mortality.

    PubMed

    Howard, Virginia J; Kleindorfer, Dawn O; Judd, Suzanne E; McClure, Leslie A; Safford, Monika M; Rhodes, J David; Cushman, Mary; Moy, Claudia S; Soliman, Elsayed Z; Kissela, Brett M; Howard, George

    2011-04-01

    While black-white and regional disparities in U.S. stroke mortality rates are well documented, the contribution of disparities in stroke incidence is unknown. We provide national estimates of stroke incidence by race and region, contrasting these to publicly available stroke mortality data. This analysis included 27,744 men and women without prevalent stroke (40.4% black), aged ≥45 years from the REasons for Geographic And Racial Differences in Stroke (REGARDS) national cohort study, enrolled 2003-2007. Incident stroke was defined as first occurrence of stroke over 4.4 years of follow-up. Age-sex-adjusted stroke mortality rates were calculated using data from the Centers for Disease Control and Prevention (CDC) Wide-Ranging Online Data for Epidemiological Research (WONDER) System. There were 460 incident strokes over 113,469 person-years of follow-up. Relative to the rest of the United States, incidence rate ratios (IRRs) of stroke in the southeastern stroke belt and stroke buckle were 1.06 (95% confidence interval [CI], 0.87-1.29) and 1.19 (95% CI, 0.96-1.47), respectively. The age-sex-adjusted black/white IRR(black) was 1.51 (95% CI, 1.26-1.81), but for ages 45-54 years the IRR(black) was 4.02 (95% CI, 1.23-13.11) while for ages 85+ it was 0.86 (95% CI, 0.33-2.20). Generally, the IRRs(black) were less than the mortality rate ratios (MRRs) across age groups; however, only in ages 55-64 years and 65-74 years did the 95% CIs of IRRs(black) not include the MRR(black) . The MRRs for regions were within 95% CIs for IRRs. National patterns of black-white and regional differences in stroke incidence are similar to those for stroke mortality; however, the magnitude of differences in incidence appear smaller. Copyright © 2011 American Neurological Association.

  10. Radiocarbon concentration in tree-ring samples collected in the south-west Slovakia (1974-2013).

    PubMed

    Kontuľ, I; Ješkovský, M; Kaizer, J; Šivo, A; Richtáriková, M; Povinec, P P; Čech, P; Steier, P; Golser, R

    2017-08-01

    Radiocarbon measurements of tree-ring samples collected in Vysoká pri Morave were compared with tree-ring data of the Žlkovce monitoring station situated 5km south-east from the Jaslovské Bohunice Nuclear Power Plant (NPP). Radiocarbon concentrations in Vysoká pri Morave and in Žlkovce tree rings were decreasing exponentially with decay constants of 14.48±1.23 y and 17.96±1.97 y, respectively, in agreement with similar results obtained at other radiocarbon stations. The Suess effect, represented by a dilution in (14)C levels by fossil fuel CO2 emissions, was observed in both tree-ring data sets. The Vysoká pri Morave (14)C data were during 1974-1995 systematically lower by about 50‰ than the Schauinsland (Germany) clean air reference values due to a regional fossil-fuel impact. However, after 1996 the Vysoká pri Morave (14)C data were closer to the Schauinsland data due to lower CO2 emissions as a result of closing some of the heavy industry technologies in the region. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Health disparities in Milwaukee by socioeconomic status.

    PubMed

    Vila, Peter M; Swain, Geoffrey R; Baumgardner, Dennis J; Halsmer, Sarah E; Remington, Patrick L; Cisler, Ron A

    2007-10-01

    In 2006, the city of Milwaukee ranked worse than any Wisconsin county for health outcomes and worse than all but 1 county for health determinants. To further examine disparities in health, Milwaukee city ZIP codes were stratified into 3 groups (lower, middle, and upper) by socioeconomic status (SES). Health determinants (15 measures) and health outcomes (2 measures) were compared across these ZIP code groups, and to the rest of Wisconsin. The risk ratio for the lower SES group in comparison to the upper SES group was at least 2.0 for 5 of the 17 measures examined, and was at least 1.5 for 13 of the 17 measures. The upper SES group in Milwaukee, while the healthiest in the city, was worse than the state average in 6 measures. Large health disparities within the city of Milwaukee are associated with geographic regions of differing socioeconomic status. As the state's largest urban center, Milwaukee's relatively poor health and significant health disparities have a considerable impact on the overall health of the state. To improve population health in Wisconsin, substantial efforts and resources are needed to address these disparities, and their related upstream factors.

  12. Radiocarbon dating of glacier ice: overview, optimisation, validation and potential

    NASA Astrophysics Data System (ADS)

    Uglietti, Chiara; Zapf, Alexander; Jenk, Theo Manuel; Sigl, Michael; Szidat, Sönke; Salazar, Gary; Schwikowski, Margit

    2016-12-01

    High-altitude glaciers and ice caps from midlatitudes and tropical regions contain valuable signals of past climatic and environmental conditions as well as human activities, but for a meaningful interpretation this information needs to be placed in a precise chronological context. For dating the upper part of ice cores from such sites, several relatively precise methods exist, but they fail in the older and deeper parts, where plastic deformation of the ice results in strong annual layer thinning and a non-linear age-depth relationship. If sufficient organic matter such as plant, wood or insect fragments were found, radiocarbon (14C) analysis would have thus been the only option for a direct and absolute dating of deeper ice core sections. However such fragments are rarely found and, even then, they would not be very likely to occur at the desired depth and resolution. About 10 years ago, a new, complementary dating tool was therefore introduced by our group. It is based on extracting the µg-amounts of the water-insoluble organic carbon (WIOC) fraction of carbonaceous aerosols embedded in the ice matrix for subsequent 14C dating. Since then this new approach has been improved considerably by reducing the measurement time and improving the overall precision. Samples with ˜ 10 µg WIOC mass can now be dated with reasonable uncertainty of around 10-20 % (variable depending on sample age). This requires about 300 to 800 g of ice for WIOC concentrations typically found in midlatitude and low-latitude glacier ice. Dating polar ice with satisfactory age precision is still not possible since WIOC concentrations are around 1 order of magnitude lower. The accuracy of the WIOC 14C method was validated by applying it to independently dated ice. With this method, the deepest parts of the ice cores from Colle Gnifetti and the Mt Ortles glacier in the European Alps, Illimani glacier in the Bolivian Andes, Tsambagarav ice cap in the Mongolian Altai, and Belukha glacier

  13. Radiocarbon dating of plant macrofossils from tidal-marsh sediment

    USGS Publications Warehouse

    Kemp, A.C.; Nelson, Alan R.; Horton, B.P.

    2013-01-01

    Tidal-marsh sediment is an archive of Holocene environmental changes, including movements of sea and land levels, and extreme events such as hurricanes, earthquakes, and tsunamis. Accurate and precise radiocarbon dating of environmental changes is necessary to estimate rates of change and the recurrence interval (frequency) of events. Plant macrofossils preserved in growth position (or deposited soon after death) in tidal-marsh sediment are ideal samples for dating such changes. In this chapter, we focus on the selection of plant macrofossils for radiocarbon dating and the application of ages from different types of macrofossils to varied research projects, and make recommendations for selection and preparation of tidal-marsh samples for dating.

  14. The radiocarbon budget for Mono Lake: an unsolved mystery

    USGS Publications Warehouse

    Broecker, W.S.; Wanninkhof, R.; Mathieu, G.; Peng, T.-H.; Stine, S.; Robinson, S.; Herczeg, A.; Stuiver, M.

    1988-01-01

    Since 1957 the 14C C ratio of the dissolved inorganic carbon in Mono Lake has risen by about 60???. The magnitude of this increase is about four times larger than that expected from the invasion of bomb-produced 14C from the atmosphere. We have eliminated the following explanations: (1) measurement error, (2) an unusually high physical exchange rate for non-reactive gases, (3) inorganic enhancement of the CO2 exchange rate, and (4) biological enhancement of the CO2 exchange rate. Clandestine disposal of waste radiocarbon remains a dark-horse explanation. In the course of our investigations we have uncovered evidence for at least one episodic input of radiocarbon-free carbon to the lake over the last 1000 years. We speculate that this injection was related to a hydrothermal event resulting from sublacustrine volcanic activity. ?? 1988.

  15. Radiocarbon age of the kohitsugire calligraphy and the kiwamefuda certificate

    NASA Astrophysics Data System (ADS)

    Oda, Hirotaka; Ikeda, Kazuomi; Nakamura, Toshio

    2007-06-01

    Kohitsugire are ancient paper sheets with elegant calligraphy. They were originally leaves of ancient manuscripts written mainly from the 8th to the 15th century. Old manuscripts are rarely discovered as complete books; therefore, kohitsugire can be significant materials for historical studies if the written ages or the calligraphists or both are known. Most of kohitsugire have kiwamefuda certificates which identify the calligraphists. This is also a clue about the written age. In this study, we determined the written ages of kohitsugire from three viewpoints: radiocarbon dating, calligraphical investigation and the kiwamefuda. Comparison of radiocarbon age and the calligraphical evidence of each kohitsugire give fair agreement. The results are, however, in obvious conflict with the age of the calligraphist noted on the kiwamefuda, and showed the doubtful reliability of kiwamefuda.

  16. New radiocarbon dates on the cereals from Wadi Kubbaniya

    SciTech Connect

    Wendorf, F.; Schild, R.; Close, A.E.; Donahue, D.J.; Jull, A.J.T.; Zabel, T.H.; Wieckowska, H.; Kobusiewicz, M.; Issawi, B.; el Hadidi, N.

    1984-01-01

    In 1978, three carbonized grains of barley and a carbonized grain of einkorn wheat were found in a buried hearth at a Late Paleolithic site at Wadi Kubbaniya in Egypt. In 1981, two large clusters of barley seeds, which were identified as six-row barley and thus domestic, were found at a nearby site of comparable age. Numerous grinding stones, presumed to have been used for processing the cereals, were found in these and other sites, often deeply buried, and 30 radiocarbon dates placed the occupations between 18,500 and 17,000 radiocarbon years ago. These finds led us to suggest an early origin of food production, with implications for the initial development of complex societies. Several barley seeds were analyzed by electron spin resonance spectroscopy to determine the maximal temperature to which they had been subjected before burial. Six barley seeds and three small pieces of wood charcoal were dated directly by using a tandem accelerator mass spectrometer.

  17. NON-DESTRUCTIVE RADIOCARBON DATING: NATURALLY MUMMIFIED INFANT BUNDLE FROM SW TEXAS

    SciTech Connect

    Steelman, K L; Rowe, M W; Turpin, S A; Guilderson, T P; Nightengale, L

    2004-09-07

    Plasma oxidation was used to obtain radiocarbon dates on six different materials from a naturally mummified baby bundle from the Lower Pecos River region of southwest Texas. This bundle was selected because it was thought to represent a single event and would illustrate the accuracy and precision of the plasma oxidation method. Five of the materials were clearly components of the original bundle with 13 dates combined to yield a weighted average of 2135 {+-} 11 B.P. Six dates from a wooden stick of Desert Ash averaged 939 {+-} 14 B.P., indicating that this artifact was not part of the original burial. Plasma oxidation is shown to be a virtually non-destructive alternative to combustion. Because only sub-milligram amounts of material are removed from an artifact over its exposed surface, no visible change in fragile materials has been observed, even under magnification. The method is best applied when natural organic contamination is unlikely and serious consideration of this issue is needed in all cases. If organic contamination is present, it will have to be removed before plasma oxidation to obtain accurate radiocarbon dates.

  18. Test of Martin's overkill hypothesis using radiocarbon dates on extinct megafauna.

    PubMed

    Surovell, Todd A; Pelton, Spencer R; Anderson-Sprecher, Richard; Myers, Adam D

    2016-01-26

    Following Martin [Martin PS (1973) Science 179:969-974], we propose the hypothesis that the timing of human arrival to the New World can be assessed by examining the ecological impacts of a small population of people on extinct Pleistocene megafauna. To that end, we compiled lists of direct radiocarbon dates on paleontological specimens of extinct genera from North and South America with the expectation that the initial decline of extinct megafauna should correspond in time with the initial evidence for human colonization and that those declines should occur first in eastern Beringia, next in the contiguous United States, and last in South America. Analyses of spacings and frequency distributions of radiocarbon dates for each region support the idea that the extinction event first commenced in Beringia, roughly 13,300-15,000 BP. For the United States and South America, extinctions commenced considerably later but were closely spaced in time. For the contiguous United States, extinction began at ca. 12,900-13,200 BP, and at ca. 12,600-13,900 BP in South America. For areas south of Beringia, these estimates correspond well with the first significant evidence for human presence and are consistent with the predictions of the overkill hypothesis.

  19. Test of Martin’s overkill hypothesis using radiocarbon dates on extinct megafauna

    PubMed Central

    Surovell, Todd A.; Pelton, Spencer R.; Anderson-Sprecher, Richard; Myers, Adam D.

    2016-01-01

    Following Martin [Martin PS (1973) Science 179:969–974], we propose the hypothesis that the timing of human arrival to the New World can be assessed by examining the ecological impacts of a small population of people on extinct Pleistocene megafauna. To that end, we compiled lists of direct radiocarbon dates on paleontological specimens of extinct genera from North and South America with the expectation that the initial decline of extinct megafauna should correspond in time with the initial evidence for human colonization and that those declines should occur first in eastern Beringia, next in the contiguous United States, and last in South America. Analyses of spacings and frequency distributions of radiocarbon dates for each region support the idea that the extinction event first commenced in Beringia, roughly 13,300–15,000 BP. For the United States and South America, extinctions commenced considerably later but were closely spaced in time. For the contiguous United States, extinction began at ca. 12,900–13,200 BP, and at ca. 12,600–13,900 BP in South America. For areas south of Beringia, these estimates correspond well with the first significant evidence for human presence and are consistent with the predictions of the overkill hypothesis. PMID:26504205

  20. Radiocarbon analysis of halophilic microbial lipids from an Australian salt lake

    NASA Astrophysics Data System (ADS)

    Bray, P. Sargent; Jones, Claudia M.; Fallon, Stewart J.; Brocks, Jochen J.; George, Simon C.

    2012-01-01

    Assigning accurate dates to hypersaline sediments opens important terrestrial records of local and regional paleoecologies and paleoclimatology. However, as of yet no conventional method of dating hypersaline systems has been widely adopted. Biomarker, mineralogical, and radiocarbon analyses of sediments and organic extracts from a shallow (13 cm) core from a hypersaline playa, Lake Tyrrell, southeastern Australia, produce a coherent age-depth curve beginning with modern microbial mats and extending to ~ 7500 cal yr BP. These analyses are furthermore used to identify and constrain the timing of the most recent change in hydrological regime at Lake Tyrrell, a shift from a clay deposit to the precipitation of evaporitic sands occurring at some time between ~ 4500 and 7000 yr. These analyses show the potential for widespread dating of hypersaline systems integrating the biomarker approach, reinforce the value of the radiocarbon content of biomarkers in understanding the flow of carbon in modern ecologies, and validate the temporal dimension of data provided by biomarkers when dating late Quaternary sediments.

  1. New radiocarbon ages from cirques in Colorado Front Range

    SciTech Connect

    Davis, P.T. . Dept. Natural Science); Birkeland, P.W. . Dept. Geological Science); Caine, N. . Dept. of Geography); Rodbell, D.T. )

    1992-01-01

    The authors recovered sediment cores 3.1 m long from Blue Lake ([approximately]37m water depth, [approximately]3,445m a.s.l., 40[degree]5 minutes 20 seconds N, 105[degree]37 minutes 08 seconds W) and 2.7m long from Lake Dorothy ([approximately]35m water depth, [approximately]3,675m a.s.l., 40[degree]00 minutes 46 seconds N, 105[degree]41 minutes 11 seconds W). A light-weight percussion coring system suspended from perlon ropes was used because of sediment thicknesses, water depths, and ski-backpacking requirements. Lake ice provided a stable coring platform. One purpose of the project is provision of a high-resolution record of environmental change in the subalpine/alpine ecotone during the Holocene, under the auspices of the Niwot Ridge Long-Term Ecological Research program. The sediment cores also provide minimum-limiting radiocarbon ages for deglaciation of cirques and the deposits that impound their tarns. Here the authors report on this second purpose. The Blue Lake core bottomed in sandy, gray, inorganic sediment, presumably glacial diamict. A bulk sample from 2.8--2.9m depth yielded a conventional radiocarbon age of 12,275[+-]345 yrs BP. Thus, ice retreated from the site by 12 ka. Since 12 ka both glacial and rock-glacial sediments have been deposited upvalley; some of these events may be recognized in the core. In contrast, the Lake Dorothy core did not penetrate gray inorganic diamict and is entirely organic-rich. A bulk sample from 2.65--2.7m depth yielded a conventional radiocarbon age of 10,910 [+-] 320 yrs BP. Thus, the moraines impounding the lake are 2--3 times older than suggested by a combination of relative-age methods and one radiocarbon age from surface sediments.

  2. Foraminiferal radiocarbon record of northeast Pacific decadal subsurface variability

    NASA Astrophysics Data System (ADS)

    Roach, Lydia D.; Charles, Christopher D.; Field, David B.; Guilderson, Thomas P.

    2013-09-01

    The decadal dynamics of the subsurface North Pacific Ocean are largely inaccessible beyond sparse instrumental observations spanning the last 20 years. Here we present a ˜200 year long record of benthic foraminiferal radiocarbon (Δ14C), extracted at biennial resolution from the annually laminated sediments at the Santa Barbara Basin (SBB) depocenter (˜600 m). The close match between core top benthic foraminiferal Δ14C values and the Δ14C of seawater dissolved inorganic carbon (DIC) suggests that benthic foraminifera faithfully capture the bottom water radiocarbon concentrations, as opposed to that of the deeper (>0.5 cm) sediment porewater zone. The full time series of benthic foraminiferal Δ14C displays significant variability on decadal timescales, with excursions on the order of 40‰. These excursions are overprinted by a unidirectional trend over the late 20th century that likely reflects the sedimentary incorporation of bomb radiocarbon (via remineralized particulate organic carbon). We isolate this trend by means of a one-dimensional oxidation model, which considers the possible contribution of remineralized particles to the total ambient carbon pool. This oxidation model also considers the possible influence of carbon with a variety of sources (ages). Though variable oxidation of preaged carbon could exert a strong influence on benthic foraminiferal radiocarbon variability, the totality of evidence points to the vertical density structure along the Southern California Margin (SCM) as the primary driver of the SBB benthic foraminiferal Δ14C record. For example, intervals characterized by significantly lower Δ14C values correspond to periods of enhanced upwelling and subsurface equatorward flow along the SCM.

  3. One country, two worlds - the health disparity in China.

    PubMed

    Meng, Qingyue; Zhang, Jian; Yan, Fei; Hoekstra, Edward J; Zhuo, Jiatong

    2012-01-01

    As result of its spectacular economic growth, millions of Chinese have been lifted out of poverty, making China a model for impoverished countries. Although, for many, economic growth has led to prosperity, ever-growing disparities exist between those who have benefited from the economic advancement and those left behind. Massive gaps in development exist between: regions, urban and rural and social groups. This contribution is to develop a detailed understanding of the health disparity in China by examining the discrepancies in major health indicators. Current efforts to reduce the disparities, and its challenges, opportunities and global implications are also assessed.

  4. Year of Birth Determination Using Radiocarbon Dating of Dental Enamel

    SciTech Connect

    Buchholz, B A; Spalding, K L

    2009-03-10

    Radiocarbon dating is typically an archaeological tool rather than a forensic one. Recently however, we have shown that the amount of radiocarbon present in tooth enamel, as a result of nuclear bomb testing during the cold war, is a remarkably accurate indicator of when a person is born. Enamel isolated from human teeth is processed to form graphite and carbon-14 ({sup 14}C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, {sup 14}C levels in the enamel represent {sup 14}C levels in the atmosphere at the time of its formation. In this paper we describe the strategy used to determine the date of birth of an individual based on radiocarbon levels in tooth enamel, focusing on the methodology of this strategy. Year of birth information can significantly assist police investigators when the identity of a deceased individual is unknown. In such cases police will try to match particulars of the unidentified individual (which is often only gender and/or an estimate of age), with particulars from missing persons lists.

  5. Year of birth determination using radiocarbon dating of dental enamel.

    PubMed

    Buchholz, B A; Spalding, K L

    2010-05-01

    Radiocarbon dating is typically an archaeological tool rather than a forensic one. Recently however, we have shown that the amount of radiocarbon present in tooth enamel, as a result of nuclear bomb testing during the cold war, is a remarkably accurate indicator of when a person is born. Enamel isolated from human teeth is processed to form graphite and carbon-14 ((14)C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, (14)C levels in the enamel represent (14)C levels in the atmosphere at the time of its formation. In this paper we describe the strategy used to determine the date of birth of an individual based on radiocarbon levels in tooth enamel, focusing on the methodology of this strategy. Year of birth information can significantly assist police investigators when the identity of a deceased individual is unknown. In such cases police will try to match particulars of the unidentified individual (which is often only gender and/or an estimate of age), with particulars from missing persons lists.

  6. Agriculture, population growth, and statistical analysis of the radiocarbon record.

    PubMed

    Zahid, H Jabran; Robinson, Erick; Kelly, Robert L

    2016-01-26

    The human population has grown significantly since the onset of the Holocene about 12,000 y ago. Despite decades of research, the factors determining prehistoric population growth remain uncertain. Here, we examine measurements of the rate of growth of the prehistoric human population based on statistical analysis of the radiocarbon record. We find that, during most of the Holocene, human populations worldwide grew at a long-term annual rate of 0.04%. Statistical analysis of the radiocarbon record shows that transitioning farming societies experienced the same rate of growth as contemporaneous foraging societies. The same rate of growth measured for populations dwelling in a range of environments and practicing a variety of subsistence strategies suggests that the global climate and/or endogenous biological factors, not adaptability to local environment or subsistence practices, regulated the long-term growth of the human population during most of the Holocene. Our results demonstrate that statistical analyses of large ensembles of radiocarbon dates are robust and valuable for quantitatively investigating the demography of prehistoric human populations worldwide.

  7. Using Radiocarbon to Test Models of Ecosystem Carbon Cycling

    NASA Astrophysics Data System (ADS)

    Trumbore, S.; Lin, H.; Randerson, J.

    2007-05-01

    The radiocarbon content of carbon stored in and respired by ecosystems provides a direct measure of ecosystem carbon dynamics that can be directly compared to model predictions. Because carbon cycles through ecosystems on a variety of timescales, the mean age of C in standing biomass and soil organic matter pools is older than the mean age of microbially respired carbon. In turn, each pathway for C transit through ecosystems my respond differently to edaphic conditions; for example, soil organic matter mean age is controlled by factors affecting stabilization of C on very long timescales, such as mineralogy, while a factor like litter quality that effects decomposition rates reflects vegetation and climate characteristics. We compare the radiocarbon signature of heterotrophically respired CO2 across a number of ecosystems with models predicted using the CASA ecosystem model. The major controls of microbially respired CO2 from ecosystems include the residence time of C in living plant pools (i.e. the age of C in litter inputs to soil) and factors that control decomposition rates (litter quality and climate). Major differences between model and measured values at low latitudes are related to how woody debris pools are treated differently in models and measurements. The time lag between photosynthesis and respiration is a key ecosystem property that defines its potential to store or release carbon given variations in annual net primary production. Radiocarbon provides a rare case where models can be directly compared with measurements to provide a test of this parameter.

  8. Radiocarbon dating of planktonic foraminifer shells: A cautionary tale

    NASA Astrophysics Data System (ADS)

    Mekik, Figen

    2014-01-01

    rate, bioturbation, winnowing, and calcite dissolution produce significant radiocarbon age offsets among multiple species of coexisting planktonic foraminifers and pteropod fragments. We compare the radiocarbon age of foraminifer species and pteropod fragments with estimates of percent calcite dissolved made with a sedimentary proxy (Globorotalia menardii fragmentation index—MFI) to delineate the effect of dissolution on radiocarbon age of foraminifers. Data from two core top transects on the Rio Grande Rise (RIO) and Ontong Java Plateau (OJP) and from down core sediments of varying sedimentation rates in the tropical Pacific (ME-27, MD98 2177, and MW91-9 56GGC) reveal that sediments with the greatest accumulation rates produce the least age offsets among coexisting species. Age offsets among coexisting foraminifers are about 3500 years on RIO, and 1000 years on OJP. Two core tops from RIO yield an age of the Last Glacial Maximum possibly due to mass displacement of younger sediments downslope. Foraminifer age increases with increasing dissolution and there is a consistent pattern of older foraminifer fragments coexisting with younger whole shells of the same species. The only exception is sediments which have experienced high dissolution where fragments are younger than whole shells. The age offset between fragments of G. menardii and its coexisting whole shells does not exceed the age offset among other coexisting foraminifer species in the same core tops.

  9. Agriculture, population growth, and statistical analysis of the radiocarbon record

    PubMed Central

    Zahid, H. Jabran; Robinson, Erick; Kelly, Robert L.

    2016-01-01

    The human population has grown significantly since the onset of the Holocene about 12,000 y ago. Despite decades of research, the factors determining prehistoric population growth remain uncertain. Here, we examine measurements of the rate of growth of the prehistoric human population based on statistical analysis of the radiocarbon record. We find that, during most of the Holocene, human populations worldwide grew at a long-term annual rate of 0.04%. Statistical analysis of the radiocarbon record shows that transitioning farming societies experienced the same rate of growth as contemporaneous foraging societies. The same rate of growth measured for populations dwelling in a range of environments and practicing a variety of subsistence strategies suggests that the global climate and/or endogenous biological factors, not adaptability to local environment or subsistence practices, regulated the long-term growth of the human population during most of the Holocene. Our results demonstrate that statistical analyses of large ensembles of radiocarbon dates are robust and valuable for quantitatively investigating the demography of prehistoric human populations worldwide. PMID:26699457

  10. Radiocarbon analysis of human remains: a review of forensic applications.

    PubMed

    Ubelaker, Douglas H

    2014-11-01

    Radiocarbon analysis of organic materials, with the comparison of values with those of the post-1950 modern bomb curve, has proven useful in forensic science to help evaluate the antiquity of evidence. Applications are particularly helpful in the study of human remains, especially with those displaying advanced decomposition of soft tissues. Radiocarbon analysis can reveal if the remains relate to the modern, post-1950 era and if so, also provide information needed to evaluate the death and birth date. Sample selection and interpretation of results must be guided by knowledge of the formation and remodeling of different human tissues, as well as contextual information and the approximate age at death of the individual represented. Dental enamel does not remodel and thus captures dietary radiocarbon values at the time of juvenile formation. Most other human tissues do remodel but at differing rates and therefore collectively offer key information relative to the estimation of the death date. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  11. Radiocarbon dating of diatom-bound organic compounds

    NASA Astrophysics Data System (ADS)

    Hatte, C.; Hodgins, G.; Jull, T.; Cruz, R.; Lange, T.; Biddulph, D.

    2006-12-01

    We present a new method for obtaining radiocarbon dates for the proteins intrinsic to diatom frustules (sillafin). By asserting age models for sediment cores that lack calcium carbonate, this method will improve interpretations of diatom-based paleoproxies either marine or lacustrine. In preparation for radiocarbon dating by Accelerator Mass Spectrometry, diatoms were first concentrated out of the sediment. Through chemical and physical treatments that will be discussed and compared here, diatoms frustules are then freed of any surface-bound organic matter. Compounds intrinsic to diatoms frustules are then released from their opal matrix by HF dissolution. Since we have eliminated any of potentially contaminating organic matter, this method differs from approaches based on specific compounds extraction from a complex organic mixture by preparative chromatography such as proposed by Ingalls et al. (2004, Mar. Chem). The advantage of our method is that it does not require heavy cost investment. The method was applied to samples from a marine core collected in the Southern Ocean, that spans the last climatic cycle. Diatoms rich sediments from a Holocene lacustrine/palustrine record from Texas were also investigated. We report on the radiocarbon dating results obtained on organic matter at each step of the chemical treatment, from bulk to sillafin and their interpretation.

  12. Why should we investigate the morphological disparity of plant clades?

    PubMed Central

    Oyston, Jack W.; Hughes, Martin; Gerber, Sylvain; Wills, Matthew A.

    2016-01-01

    Background Disparity refers to the morphological variation in a sample of taxa, and is distinct from diversity or taxonomic richness. Diversity and disparity are fundamentally decoupled; many groups attain high levels of disparity early in their evolution, while diversity is still comparatively low. Diversity may subsequently increase even in the face of static or declining disparity by increasingly fine sub-division of morphological ‘design’ space (morphospace). Many animal clades reached high levels of disparity early in their evolution, but there have been few comparable studies of plant clades, despite their profound ecological and evolutionary importance. This study offers a prospective and some preliminary macroevolutionary analyses. Methods Classical morphometric methods are most suitable when there is reasonable conservation of form, but lose traction where morphological differences become greater (e.g. in comparisons across higher taxa). Discrete character matrices offer one means to compare a greater diversity of forms. This study explores morphospaces derived from eight discrete data sets for major plant clades, and discusses their macroevolutionary implications. Key Results Most of the plant clades in this study show initial, high levels of disparity that approach or attain the maximum levels reached subsequently. These plant clades are characterized by an initial phase of evolution during which most regions of their empirical morphospaces are colonized. Angiosperms, palms, pines and ferns show remarkably little variation in disparity through time. Conifers furnish the most marked exception, appearing at relatively low disparity in the latest Carboniferous, before expanding incrementally with the radiation of successive, tightly clustered constituent sub-clades. Conclusions Many cladistic data sets can be repurposed for investigating the morphological disparity of plant clades through time, and offer insights that are complementary to more focused

  13. Eastern tropical North Pacific coral radiocarbon reveals North Pacific Gyre Oscillation (NPGO) variability

    NASA Astrophysics Data System (ADS)

    Rafter, Patrick A.; Sanchez, Sara C.; Ferguson, Julie; Carriquiry, Jose D.; Druffel, Ellen R. M.; Villaescusa, J. A.; Southon, John R.

    2017-03-01

    Fluctuations in oceanic circulation and upwelling associated with the North Pacific Gyre Oscillation (NPGO) are the largest source of salinity and nutrient concentration variability across the Pacific basin. Recent observations suggest NPGO-like variability is intensifying, but longer, ;pre-instrumental; records are required to improve our understanding of NPGO amplitude and phase change. Here, using measurements of coral skeletal chemistry from San Benedicto Island in the Eastern Tropical North Pacific (ETNP), we assess this region's suitability for reconstructing NPGO behavior. We find that coral geochemical proxy measurements of ETNP salinity and dissolved inorganic carbon radiocarbon (Δ14C) content reflect NPGO-driven gyre circulation and regional coastal upwelling. These results provide the basis for reconstructing NPGO-related ocean conditions hundreds of years prior to the modern observational record.

  14. Re-Emergence of Excess Bomb Radiocarbon in Upwelling Waters with High-Latitude Origins

    NASA Astrophysics Data System (ADS)

    Lindsay, C. M.; Lehman, S.

    2016-02-01

    The quantity of radiocarbon (14C) in the atmosphere was nearly doubled by nuclear weapons testing in the 1960s. Since then, the terrestrial biosphere and the ocean have absorbed most of the excess 14C from the atmosphere, although atmospheric radiocarbon activity (∆14C) continues to decline due to ongoing emissions of 14C-free CO2 from combustion of fossil fuels. The large transient decline in atmospheric ∆14C combined with gas exchange at the surface and spatially variable time scales of ocean mixing have led to large ∆14C gradients in the surface ocean between upwelling- and downwelling-dominated regions. These gradients continue to evolve over time. We examine the rate of change of surface ocean ∆14C between CLIVAR (2000-2011) and WOCE era (1990s) or other slightly earlier (1980s) datasets and find spatial patterns that reveal mixing between 14C-enriched mode waters, 14C-depleted deep waters and surface waters that are well-equilibrated with the atmosphere. The ∆14C of mode water reaching equatorial upwelling regions has increased between the WOCE and CLIVAR time periods, and the greater contribution of 14C to the low-latitude surface ocean appears to have significantly offset the ∆14C decline otherwise imparted by air-sea gas exchange with the atmosphere. Consequently, ∆14C gradients between low-latitude upwelling regions and gyre centers have weakened proportionally more than between gyre centers and regions where pre-industrial water still upwells, such as the Southern Ocean. Properly accounting for the re-emergence of water with post-industrial characteristics is important to constrain earth system models that seek to explain DIC, pH and other anthropogenically perturbed tracers in the surface ocean. Because of the history of ∆14C in the atmosphere, ocean ∆14C is a useful tracer for this purpose.

  15. Using A Time-Dependent Dynamical Box Model to Understand Intermediate Water Records of Radiocarbon and Temperature

    NASA Astrophysics Data System (ADS)

    Hines, S.; Adkins, J. F.; Thompson, A. F.

    2016-12-01

    The circulation of Intermediate Waters influences global oceanic heat and carbon transport and changes in their distributions are also tied to glacial-interglacial climate transitions. In the modern ocean, temperature dominates interior density gradients and thus, to a large extent controls the deep circulation. Our chief tool for understanding the rate of this deep circulation comes from radiocarbon. Coupled radiocarbon and U/Th dates on deep-sea Desmophyllum dianthus corals allows for the reconstruction of past Intermediate Water circulation rates. Additionally, clumped isotope-based temperature estimates yield insight into the physical mechanisms contributing to circulation variability. We present deep-sea coral radiocarbon and clumped isotope temperature records from the North Atlantic and Southern Ocean, which show a high amount of variability during Heinrich Stadial 2 and the Antarctic Cold Reversal. Radiocarbon data from the north and south are very consistent with each other, and other datasets from similar depths broadly agree. We further explore the ocean dynamics behind our observations using a time-dependent dynamical box model. This model consists of an ACC channel, an Atlantic basin, and a Pacific basin. There are multiple layers representing different density classes and the volume of the boxes responds to realistic residual-mean Southern Ocean dynamics. Our model has a surface buoyancy flux, wind forcing and transfer of mass between the basins in the ACC region, diffusive upwelling in the basins, and North Atlantic Deep Water formation. The model solves for the circulation and stratification in addition to the volumes of the boxes. We use this model with added biogeochemistry to explore the mechanisms driving Intermediate Water signals observed during Marine Isotope Stage 2 and the deglaciation. Our box model is able to offer an independent and dynamical perspective to help understand these paleo records.

  16. Sharing a disparate landscape

    NASA Astrophysics Data System (ADS)

    Ali-Khan, Carolyne

    2010-06-01

    Working across boundaries of power, identity, and political geography is fraught with difficulties and contradictions. In Tali Tal and Iris Alkaher's, " Collaborative environmental projects in a multicultural society: Working from within separate or mutual landscapes?" the authors describe their efforts to do this in the highly charged atmosphere of Israel. This forum article offers a response to their efforts. Writing from a framework of critical pedagogy, I use the concepts of space and time to anchor my analysis, as I examine the issue of power in this Jew/Arab collaborative environmental project. This response problematizes "sharing" in a landscape fraught with disparities. It also looks to further Tal and Alkaher's work by geographically and politically grounding it in the broader current conflict and by juxtaposing sustainability with equity.

  17. [Regional disparities in infant mortality in Colombia].

    PubMed

    Jaramillo-Mejía, Marta C; Chernichovsky, Dov; Jiménez-Moleón, José J

    2013-01-01

    To study the variations in infant mortality rate (IMR) across Colombia's 33 administrative departments over the period 2003-2009, examine persistency of variations across departments over time, and relate those variations to the impact of socio-economic conditions and availability of care on IMR. Using vital statistics and related socio-economic data we establish three types of analysis according to: (a) the variation of the departmental IMR (2003-2009), (b) the association between the departmental IMR and its key determinants over time, and (c) the lines of causality and relative impact of different factors, by using structural equations. The 4.7 fold ratio between the highest and lowest departmental IMR (2009) may be underestimated considering underreporting, especially in low-income departments. There is a negative association between the departmental IMR with time and a set of highly correlated variables, such as the mother education, income per capita, health insurance level and access to services. The effect of better insurance, availability of private beds, and having doctors attending mothers, eclipse the impact of better socioeconomic conditions. The range of services does not appear to be influenced by a rational policy; resources are not allocated according to the need, but with the general development. Private beds are made available where there is better health insurance.

  18. Sub-ice shelf sediment geochronology utilizing novel radiocarbon methodology for highly detrital sediments

    NASA Astrophysics Data System (ADS)

    Subt, C.; Yoon, H. I.; Yoo, K. C.; Lee, J. I.; Leventer, A.; Domack, E. W.; Rosenheim, B. E.

    2017-04-01

    Sub-ice shelf sediments near Larsen C ice shelf (LIS-C) show fine-scale rhythmic laminations that could provide a near-continuous seasonal-resolution record of regional ice mass changes. Despite the great potential of these sediments, a dependable Late Quaternary chronology is difficult to generate, rendering the record incomplete. As with many marginal Antarctic sediments, in the absence of preserved carbonate microfossils, the reliability of radiocarbon chronologies depends on presence of high proportions of autochthonous organic carbon with minimized detrital organic carbon. Consequently, acid insoluble organic (AIO) 14C dating works best where high productivity drives high sediment accumulation rates, but can be problematic in condensed sequences with high proportions of detrital organic carbon. Ramped PyrOx 14C dating has progressively been shown to improve upon AIO 14C dates, to the point of matching foraminiferal carbonate 14C dates, through differential thermochemical degradation of organic components within samples. But in highly detrital sediments, proportions of contemporaneously deposited material are too low to fully separate autochthonous organic carbon from detrital carbon in samples large enough to 14C date. We introduce two modifications of the Ramped PyrOx 14C approach applied to highly detrital sediments near LIS-C to maximize accuracy by utilizing ultra-small fractions of the highly detrital AIO material. With minimization of the uncertainty cost, these techniques allow us to generate chronologies for cores that would otherwise go undated, pushing the limits of radiocarbon dating to regions and facies with high proportions of pre-aged detritus. Wider use of these techniques will enable more coordinated a priori coring efforts to constrain regional glacial responses to rapid warming where sediments had previously been thought too difficult to date.

  19. Dating the time of birth: A radiocarbon calibration curve for human eye-lens crystallines

    NASA Astrophysics Data System (ADS)

    Kjeldsen, Henrik; Heinemeier, Jan; Heegaard, Steffen; Jacobsen, Christina; Lynnerup, Niels

    2010-04-01

    Radiocarbon bomb-pulse dating has been used to measure the formation age of human eye-lens crystallines. Lens crystallines are special proteins in the eye-lens that consist of virtually inert tissue. The experimental data show that the radiocarbon ages to a large extent reflect the time of birth, in accordance with expectations. Moreover, it has been possible to develop an age model for the formation of the eye-lens crystallines. From this model a radiocarbon calibration curve for lens crystallines has been calculated. As a consequence, the time of birth of humans can be determined with an accuracy of a few years by radiocarbon dating.

  20. Compound-specific Radiocarbon dating - a tool for dating lake sediments?

    NASA Astrophysics Data System (ADS)

    Birkholz, A.; Gierga, M.; Hajdas, I.; Smittenberg, R.; Wacker, L.; Bernasconi, S. M.

    2012-04-01

    Worldwide lake sediments provide information about environmental changes that took place in the past. Chronologies of these natural archives are often based on radiocarbon ages of recognizable terrestrial macrofossils that are deposited soon after their biosynthesis. However, in many instances reliable dating is not possible due to a lack of macrofossils that can be dated using radiocarbon (14C). On the other hand technical development in AMS 14C dating allows measurements of very small amounts of Carbon (micrograms) allowing to date biomarkers. Since the introduction of compound-specific radiocarbon analysis (CSRA) by Eglinton et al. (1996) this method has been used for an increasing number of studies. Nevertheless, there are only few examples of using CSRA to date sedimentary records of lakes (e.g. Uchikawa et al. 2008). Our project of CSRA on lake sediments was designed to study: (1) the build-up and reactivity of the soil organic carbon (SOC) pool and its response to climatic and environmental changes and (2) the possibility of using biomarkers as material suitable for dating lake deposits. As the lake sedimentary organic matter consists of a mixture between aquatic and terrigenous matter, compounds with an unequivocal terrigenous source need to be isolated. In this study we are targeting higher plant waxes (long chain n-alkanes and fatty acids) and branched GDGTs produced by soil bacteria. Moreover soil-derived molecular compounds found in a well-dated lake sedimentary record were analysed in order to access the role of refractory SOC, which is an important pool responsible for long-term carbon storage. When compared to the depositional age of the sediment, the age of the terrestrial lipids and organic carbon fractions provides an average residence time of these lipids and fractions in the SOC pool. Changes in the age-difference between sediment and soil-derived organic compounds over time can give an estimate of SOC build-up and evolution. We will present

  1. Large variations in the Holocene marine radiocarbon reservoir effect reflect ocean circulation and climatic changes

    NASA Astrophysics Data System (ADS)

    Hua, Quan; Webb, Gregory E.; Zhao, Jian-xin; Nothdurft, Luke D.; Lybolt, Matthew; Price, Gilbert J.; Opdyke, Bradley N.

    2015-07-01

    Accurate radiocarbon dating of marine samples requires knowledge of the marine radiocarbon reservoir effect. This effect for a particular site/region is generally assumed constant through time when calibrating marine 14C ages. However, recent studies have shown large temporal variations of several hundred to a couple of thousand years in this effect for a number of regions during the late Quaternary and Holocene. Here we report marine radiocarbon reservoir correction (ΔR) for Heron Reef and Moreton Bay in southwestern (SW) Pacific for the last 8 ka derived from 14C analysis of 230Th-dated corals. Most of our ΔR for the last ∼5.4 ka agree well with their modern value, but large ΔR variability of ∼410 yr (from trough to peak) with possible decadal/centennial fluctuations is evident for the period ∼5.4-8 ka. The latter time interval also has significant variations with similar features in previously published ΔR values for other sites in the Pacific, including southern Peru-northern Chile in southeastern (SE) Pacific, the South China Sea, Vanuatu and Papua New Guinea, with the largest magnitude of ∼920 yr from SE Pacific. The mechanisms for these large ΔR variations across the Pacific during the mid-Holocene are complex processes involving (1) changes in the quantity and 14C content of upwelled waters in tropical east Pacific (TEP) (frequency and intensity of ocean upwelling in the TEP, and contribution of Subantarctic Mode Water to the upwelled waters, which is influenced by the intensity and position of southern westerly winds), and (2) variations in ocean circulation associated with climate change (La Niña/El Niño conditions, intensity of easterly trade winds, positions of the Intertropical Convergence Zone and the South Pacific Convergence Zone), which control the spreading of the older upwelled surface waters in the TEP to the western sites. Our results imply the need for employing temporal changes in ΔR values, instead of constant (modern) values

  2. Geomorphic and paleoclimatic implications of latest Pleistocene radiocarbon dates from colluvium-mantled hollows, California

    SciTech Connect

    Reneau, S.L.; Dietrich, W.E.; Dorn, R.I.; Berger, C.R.; Rubin, M.

    1986-08-01

    Radiocarbon analyses of charcoal from basal colluvium in 11 California hollows show a clustering of dates between 9000 and 15,000 B.P., an indication that changes in the storage and discharge of colluvium from hillslopes accompanied the Pleistocene-Holocene transition. Hollows are sites of topographically induced convergence and deposition of colluvial debris, and evacuation of this debris was apparently more thorough and possibly more frequent in the latest Pleistocene, perhaps due to a combination of changes in vegetation and rainfall characteristics. One hypothesis is that greater storm intensities occurred in the latest Pleistocene and induced a higher frequency of landslides in hollows and a regional extension of channel heads upslope relative to the Holocene. During the last Pleistocene, California hollows apparently contained smaller volumes of colluvium in storage. The increased storage of debris during the Holocene may have resulted in a diminished supply of sediment to stream channels.

  3. Depth attraction and repulsion of disparate foveal stimuli.

    PubMed

    Westheimer, G; Levi, D M

    1987-01-01

    Interaction in the domain of disparity can be either of the kind where the depth difference between adjacent targets is enhanced, as if the two targets repelled each other in depth, or it may be in the opposite direction, i.e. having the character of attraction. In the fovea, interaction between stimuli is of the latter kind if targets are separated by less than 2-8 min of arc, dependent on their positions and the observer; for further separations, repulsion is exhibited. When disparate neighbors induce a change in depth of a visual feature, only a portion of the effect can be ascribed to monocular localization shifts in the two monocular retinal images. Both attraction and repulsion can occur between targets of opposite contrast. Depth interaction measured by a psychophysical nulling method increases monotonically with disparity in the regions clearly governed by the repulsion and the attraction regimen; in the transition region, repulsion overtakes attraction when the disparity becomes larger. If the concept of "pooling" of disparity is invoked to account for the affinity of seen depth of closely-adjacent stimuli, the signals involved cannot be simply those of light weighted by disparity, but must be associated with individual features.

  4. Decadally resolved Lateglacial radiocarbon evidence from New Zealand kauri

    NASA Astrophysics Data System (ADS)

    Hogg, Alan; Southon, John; Turney, Chris; Palmer, Jonathan; Bronk Ramsey, Christopher; Fenwick, Pavla; Boswijk, Gretel; Büntgen, Ulf; Friedrich, Michael; Helle, Gerhard; Hughen, Konrad; Jones, Richard; Kromer, Bernd; Noronha, Alexandra; Reinig, Frederick; Reynard, Linda; Staff, Richard; Wacker, Lukas

    2017-04-01

    The Last Glacial-Interglacial Transition (LGIT; 15,000 - 11,000 cal BP) was characterised by complex spatiotemporal patterns of climate change, with numerous studies requiring accurate chronological control to decipher leads from lags in global palaeoclimatic, -environmental and archaeological records. However, close scrutiny of the few available tree-ring chronologies and radiocarbon-dated sequences composing the IntCal13 radiocarbon (14C) calibration curve, indicates significant weakness in 14C calibration across key periods of the LGIT. Here, we present a decadally-resolved atmospheric 14C record derived from New Zealand kauri spanning Greenland Stadial 1 (GS-1; 12,900 - 11,650 cal BP). Two floating kauri 14C time series, curve-matched to IntCal13, serve as a radiocarbon backbone through GS-1. Floating Northern Hemisphere (NH) 14C datasets are matched against the new kauri data, forming a robust NH 14C time series to 14,200 cal BP. Our results show that IntCal13 is questionable from 12,200 - 11,900 cal BP and the 10,400 BP 14C plateau is approximately five decades too short. By precisely aligning Southern and Northern Hemisphere tree-ring 14C records with marine 14C sequences, we document two relatively short periods of North Atlantic Meridional Overturning Circulation (AMOC) collapse during GS-1. Hence, sustained North Atlantic cooling across GS-1 was not driven by a prolonged AMOC reduction but was probably due to an equatorward migration of the Polar Front.

  5. Recent documents dating: an approach using radiocarbon techniques.

    PubMed

    Zavattaro, D; Quarta, G; D'Elia, M; Calcagnile, L

    2007-04-11

    The possibility to develop an absolute technique, independent from the paper conservation conditions, to date recent paper documents (i.e. less than 50 years old) for forensics purposes is discussed. We suggest the possibility to use the curve representing the strong increase in the atmospheric radiocarbon concentration induced in the last 50 years by nuclear weapons tests as reference to date paper documents, with a resolution down to a few months. The results obtained in the analysis of two known age documents are presented together with a first order mathematical model developed in order to take into account the contributions of the different tree rings employed in the paper production.

  6. Allorecognition of HLA-C Mismatches by CD8+ T Cells in Hematopoietic Stem Cell Transplantation Is a Complex Interplay between Mismatched Peptide-Binding Region Residues, HLA-C Expression, and HLA-DPB1 Disparities

    PubMed Central

    Bettens, Florence; Buhler, Stéphane; Tiercy, Jean-Marie

    2016-01-01

    HLA-C locus mismatches (MMs) are the most frequent class I disparities in unrelated hematopoietic stem cell transplantation (HSCT) and have a detrimental impact on clinical outcome. Recently, a few retrospective clinical studies have reported some variability in the immunogenicity of HLA-C incompatibilities. To get better insight into presumably permissive HLA-C MMs, we have developed a one-way in vitro mixed lymphocyte reaction (MLR) assay allowing to quantify activated CD56−CD137+CD8+ lymphocytes in HLA-C incompatible combinations. T cell-mediated alloresponses were correlated with genetic markers such as HLA-C mRNA expression and the number of amino acid (aa) MMs in the α1/α2 domains (peptide-binding region). Because of the high rate of HLA-DPB1 incompatibilities in HLA-A-, B-, C-, DRB1-, and DQB1-matched unrelated HSCT patient/donor pairs, the impact of HLA-DPB1 mismatching, a potential bystander of CD4+ T cell activation, was also considered. Heterogeneous alloresponses were measured in 63 HLA-C-mismatched pairs with a positive assay in 52% of the combinations (2.3–18.6% activated CTLs), representing 24 different HLA-A~B~DRB1~DQB1 haplotypes. There was no correlation between measured alloresponses and mRNA expression of the mismatched HLA-C alleles. The HLA-C*03:03/03:04 MM did not induce any positive alloresponse in five MLRs. We also identified HLA-C*02:02 and HLA-C*06:02 as mismatched alleles with lower immunogenicity, and HLA-C*14:02 as a more immunogenic MM. A difference of at least 10 aa residues known to impact peptide/T cell receptor (TCR) binding and a bystander HLA-DPB1 incompatibility had a significant impact on CTL alloreactivity (p = 0.021). The same HLA-C MM, when recognized by two different responders with the same HLA haplotypes, was recognized differently, emphasizing the role of the T-cell repertoire of responding cells. In conclusion, mismatched HLA-C alleles differing by 10 or more aas in the peptide/TCR-binding region, when

  7. Molecular and radiocarbon composition of plant wax lipids and lignin phenols in Alaskan Arctic river sediments

    NASA Astrophysics Data System (ADS)

    Stites-Clayton, C.; Feng, X.; Montlucon, D.; Holmes, R. M.; Eglinton, T. I.

    2011-12-01

    The Yukon and Colville Rivers are two Arctic rivers that drain perennially frozen soils of Alaska and Northwest Canada. These regions of Arctic permafrost represent a large reservoir of organic carbon (OC) that has remained inactive for millennia but may experience thawing and mobilization due to climate warming. Warming-induced release of old terrestrial carbon to the atmosphere and via fluvial transport to the oceans thus constitutes a major topic of immediate concern. It is therefore important to gain insight on the distribution and residence time of terrestrial organic matter (OM) currently exported by these arctic rivers. As two important groups of terrestrial OM biomarkers, plant wax lipids and lignin phenols are widely distributed in soils and riverine sediments, whose molecular and isotopic (13C and 14C) compositions provide a great deal of information on the source and fate of terrestrial OC during land-ocean transfer. In this study we examine the molecular composition of plant wax lipids and lignin phenols in surface and suspended sediments of Colville and Yukon. Individual compounds are isolated on preparative gas and liquid chromatography for radiocarbon dating. The molecular composition and radiocarbon age of terrestrial biomarkers are compared with those in other Arctic rivers with different drainage basin characteristics and varying permafrost coverage. Such comparisons may document the release of old permafrost carbon in rivers strongly affected by warming and will provide novel insights on the fate of permafrost carbon within Arctic river drainage basins. The results have important implications to carbon cycle both at regional and global scales.

  8. Radiocarbon dating and wood density chronologies of mangrove trees in arid Western Australia.

    PubMed

    Santini, Nadia S; Hua, Quan; Schmitz, Nele; Lovelock, Catherine E

    2013-01-01

    Mangrove trees tend to be larger and mangrove communities more diverse in tropical latitudes, particularly where there is high rainfall. Variation in the structure, growth and productivity of mangrove forests over climatic gradients suggests they are sensitive to variations in climate, but evidence of changes in the structure and growth of mangrove trees in response to climatic variation is scarce. Bomb-pulse radiocarbon dating provides accurate dates of recent wood formation and tree age of tropical and subtropical tree species. Here, we used radiocarbon techniques combined with X-ray densitometry to develop a wood density chronology for the mangrove Avicennia marina in the Exmouth Gulf, Western Australia (WA). We tested whether wood density chronologies of A. marina were sensitive to variation in the Pacific Decadal Oscillation Index, which reflects temperature fluctuations in the Pacific Ocean and is linked to the instrumental rainfall record in north WA. We also determined growth rates in mangrove trees from the Exmouth Gulf, WA. We found that seaward fringing A. marina trees (~10 cm diameter) were 48 ± 1 to 89 ± 23 years old (mean ± 1 σ) and that their growth rates ranged from 4.08 ± 2.36 to 5.30 ± 3.33 mm/yr (mean ± 1 σ). The wood density of our studied mangrove trees decreased with increases in the Pacific Decadal Oscillation Index. Future predicted drying of the region will likely lead to further reductions in wood density and their associated growth rates in mangrove forests in the region.

  9. Radiocarbon Dating and Wood Density Chronologies of Mangrove Trees in Arid Western Australia

    PubMed Central

    Santini, Nadia S.; Hua, Quan; Schmitz, Nele; Lovelock, Catherine E.

    2013-01-01

    Mangrove trees tend to be larger and mangrove communities more diverse in tropical latitudes, particularly where there is high rainfall. Variation in the structure, growth and productivity of mangrove forests over climatic gradients suggests they are sensitive to variations in climate, but evidence of changes in the structure and growth of mangrove trees in response to climatic variation is scarce. Bomb-pulse radiocarbon dating provides accurate dates of recent wood formation and tree age of tropical and subtropical tree species. Here, we used radiocarbon techniques combined with X-ray densitometry to develop a wood density chronology for the mangrove Avicennia marina in the Exmouth Gulf, Western Australia (WA). We tested whether wood density chronologies of A. marina were sensitive to variation in the Pacific Decadal Oscillation Index, which reflects temperature fluctuations in the Pacific Ocean and is linked to the instrumental rainfall record in north WA. We also determined growth rates in mangrove trees from the Exmouth Gulf, WA. We found that seaward fringing A. marina trees (∼10 cm diameter) were 48±1 to 89±23 years old (mean ± 1σ) and that their growth rates ranged from 4.08±2.36 to 5.30±3.33 mm/yr (mean ±1σ). The wood density of our studied mangrove trees decreased with increases in the Pacific Decadal Oscillation Index. Future predicted drying of the region will likely lead to further reductions in wood density and their associated growth rates in mangrove forests in the region. PMID:24265797

  10. Developing inorganic carbon-based radiocarbon chronologies for Holocene lake sediments in arid NW China

    NASA Astrophysics Data System (ADS)

    Zhang, Jiawu; Ma, Xueyang; Qiang, Mingrui; Huang, Xiaozhong; Li, Shuang; Guo, Xiaoyan; Henderson, Andrew C. G.; Holmes, Jonathan A.; Chen, Fahu

    2016-07-01

    Inorganic carbonates are often used to establish radiocarbon (14C) chronologies for lake sediments when terrestrial plant remains (TPR) are rare or when bulk organic matter is insufficient for dating, a problem that is common for many lakes in arid regions. However, the reservoir effect (RE), as well as old carbon contributed from the lakes catchment make it difficult to establish reliable chronologies. Here we present a systematic study of inorganic 14C ages of two lake-sediment sequences, one from a small-enclosed saline lake - Lake Gahai in Qaidam Basin, and the other from a large freshwater lake - Lake Bosten in Xinjiang. Modern dissolved inorganic carbon (DIC) of the lakes, paleo-lake sediments exposed in the catchment, and mollusk shells in core sediments from Lake Gahai were dated to assess the RE and the contribution of pre-aged carbon to the old ages in the cores. We propose a statistical regression to assess more than one RE for the 14C carbonate ages within our sedimentary sequences. Old radiocarbon ages contributed by detrital carbonates were assessed by comparing the ages of mollusk shells with those of carbonates at the same sediment depths. We established the RE of the authigenic component and assessed detrital old carbon contributions to our two sites, and this was used to correct the 14C ages. Based on this approach, we developed age models for both cores, and tested them using 210Pb ages in both cores and TPR-based 14C-ages recovered from Lake Bosten. We further tested our age models by comparing carbonate-based oxygen isotope (δ18O) records from both lakes to an independently-dated regional speleothem δ18O record. Our results suggest if sedimentary sequences are densely dated and the RE and the contribution of old carbon from detrital carbonates can be ascertained, robust chronological frameworks based on carbonate-based 14C determinations can be established.

  11. Health Disparities in Women

    PubMed Central

    Hornbuckle, Lyndsey M; Amutah-Onukagha, Ndidiamaka; Bryan, Alicia; Skidmore Edwards, Elizabeth; Madzima, Takudzwa; Massey, Kelly; May, Linda; Robinson, Leah E

    2017-01-01

    AIMS AND SCOPE Clinical Medicine Insights: Women’s Health is an international, open-access, peer-reviewed journal which considers manuscripts on all aspects of the diagnosis, management, and prevention of disorders specific to women, in addition to related genetic, pathophysiological, and epidemiological topics. Clinical Medicine Insights: Women’s Health aims to provide researchers working in this complex, quickly developing field with online, open access to highly relevant scholarly articles by leading international researchers. In a field where the literature is ever-expanding, researchers increasingly need access to up-to-date, high-quality scholarly articles on areas of specific contemporary interest. This supplement is on Health Disparities in Women. This supplement aims to address this by presenting high-quality articles that allow readers to distinguish the signal from the noise. The editor in chief hopes that through this effort, practitioners and researchers will be aided in finding answers to some of the most complex and pressing issues of our time. PMID:28579867

  12. On the radiocarbon record in banded corals: exchange parameters and net transport of /sup 14/CO/sub 2/ between atmosphere and surface ocean

    SciTech Connect

    Druffel, E.M.; Suess, H.E.

    1983-02-20

    We have made radiocarbon measurements of banded hermatypic corals from Florida, Belize, and the Galapagos Islands. Interpretation is presented here of these previously reported results. These measurements represent the /sup 14/C//sup 12/C ratios in dissolved inorganic carbon (DIOC) in the surface ocean waters of the Gulf Stream and the Peru Current at the time of coral ring formation. A depletion in radiocarbon concentration was observed incoral rings that grew from A.D. 1900--1952. It was caused by dilution of existing /sup 14/C levels with dead CO/sub 2/ from fossil fuel burning (the Suess effect, or S/sub e/). A similar trend was observed in the distribution of bomb-produced /sup 14/C in corals that had grown during the years following A.D. 1952. The concentration of bomb-produced radiocarbon was much higher in corals from temperate regions (Florida, Belize, Hawaiian Islands) than in corals from tropical regions (Galapagos Islands and Canton Island). The apparent radiocarbon ages of the surface waters in temperate and tropical oceans during the preanthropogenic period range from about 280 to 520 years B.P. (-40 to -69%). At all investigated locations, it is likely that waters at subsurface depths have the same apparent radiocarbon age of about 670 years B.P. From the change of oceanic ..delta../sup 14/C in the surface during post-bomb times, the approximate annual rate of net input of /sup 14/CO/sub 2/ to the ocean waters is calculated to be about 8% of the prevailing /sup 14/C difference between atmosphere and ocean. From this input and from preanthropogenic ..delta../sup 14/C values found at each location, it can be seen that vertical mixing of water in the Peru Current is about 3 times greater than that in the Gulf Stream.

  13. IntCal04: A New Consensus Radiocarbon Calibration Dataset from 0-26 ka BP

    NASA Astrophysics Data System (ADS)

    Reimer, P. J.; Baillie, M. G.; Bard, E.; Beck, J. W.; Buck, C. E.; Blackwell, P. G.; Burr, G. S.; Cutler, K. B.; Damon, P. E.; Edwards, R. L.; Fairbanks, R. G.; Friedrich, M.; Guilderson, T. P.; Hogg, A. G.; Hughen, K. A.; Kromer, B.; McCormac, G.; Ramsey, C. B.; Reimer, R. W.; Remmele, S.; Southon, J. R.; Stuiver, M.; Taylor, F. W.; van der Plicht, J.; Weyhenmeyer, C. E.

    2003-12-01

    Because atmosphere 14C levels have not been constant through time, it is necessary to calibrate radiocarbon dates with known age radiocarbon datasets in order to compare paleorecords based on 14C ages and those based on other timescales. The need for a consensus calibration dataset was acknowledged by the radiocarbon community as a way of preventing confusion and the subjective use of selected datasets (1). Since then, radiocarbon calibration datasets have been developed by international collaborations and presented for ratification at the International Radiocarbon Conference (2-4). The IntCal04 Radiocarbon Calibration/Comparison Working Group has put together a dataset which incorporates existing and new measurements of tree-ring records, foraminifera from varved sediments, and corals that meet a strict set of acceptance criteria (5). Uncertainties for both the calendar time scale and the radiocarbon ages have been quantified and included in the dataset combination using a statistical technique based on the ideas of Christen and Nicholls (6) and Gomez Portugal Aguilar (7). The IntCal04 dataset, which covers the range of 0 to 26 ka BP, was presented for ratification at the 19th International Radiocarbon Conference in Wellington, New Zealand, in September, 2003. This paper will highlight the differences between IntCal98 and the new IntCal04 dataset and give an example showing the effect on the calibrated age for a Younger Dryas age sample. 1. J. Klein, J. C. Lerman, P. E. Damon, E. K. Ralph, Radiocarbon 24, 103-150 (1982). 2. M. Stuiver, Radiocarbon 28, R2-R2 (1986). 3. M. Stuiver et al., Radiocarbon 40, 1041-1083 (1998). 4. M. Stuiver, P. J. Reimer, Radiocarbon 35, 215-230 (1993). 5. P. J. Reimer et al., Radiocarbon 44, 653-661. (2002). 6. J. A. Christen, G. Nicholls, "Random-walk radiocarbon calibration." (Mathematics Department, University of Auckland, 2000). 7.D. G. P. Aguilar, C. D. Litton, A. O'Hagan, Radiocarbon 44, 195-212 (2002).

  14. A new combination of monocular and stereo cues for dense disparity estimation

    NASA Astrophysics Data System (ADS)

    Mao, Miao; Qin, Kaihuai

    2013-07-01

    Disparity estimation is a popular and important topic in computer vision and robotics. Stereo vision is commonly done to complete the task, but most existing methods fail in textureless regions and utilize numerical methods to interpolate into these regions. Monocular features are usually ignored, which may contain helpful depth information. We proposed a novel method combining monocular and stereo cues to compute dense disparities from a pair of images. The whole image regions are categorized into reliable regions (textured and unoccluded) and unreliable regions (textureless or occluded). Stable and accurate disparities can be gained at reliable regions. Then for unreliable regions, we utilize k-means to find the most similar reliable regions in terms of monocular cues. Our method is simple and effective. Experiments show that our method can generate a more accurate disparity map than existing methods from images with large textureless regions, e.g. snow, icebergs.

  15. Latitude and longitude vertical disparity

    PubMed Central

    Read, Jenny C. A.; Phillipson, Graeme P.; Glennerster, Andrew

    2010-01-01

    The literature on vertical disparity is complicated by the fact that several different definitions of the term “vertical disparity” are in common use, often without a clear statement about which is intended or a widespread appreciation of the properties of the different definitions. Here, we examine two definitions of retinal vertical disparity: elevation-latitude and elevation-longitude disparity. Near the fixation point, these definitions become equivalent, but in general, they have quite different dependences on object distance and binocular eye posture, which have not previously been spelt out. We present analytical approximations for each type of vertical disparity, valid for more general conditions than previous derivations in the literature: we do not restrict ourselves to objects near the fixation point or near the plane of regard, and we allow for non-zero torsion, cyclovergence and vertical misalignments of the eyes. We use these expressions to derive estimates of the latitude and longitude vertical disparity expected at each point in the visual field, averaged over all natural viewing. Finally, we present analytical expressions showing how binocular eye position – gaze direction, convergence, torsion, cyclovergence, and vertical misalignment – can be derived from the vertical disparity field and its derivatives at the fovea. PMID:20055544

  16. Measurements and modeling of contemporary radiocarbon in the stratosphere

    NASA Astrophysics Data System (ADS)

    Kanu, A. M.; Comfort, L. L.; Guilderson, T. P.; Cameron-Smith, P. J.; Bergmann, D. J.; Atlas, E. L.; Schauffler, S.; Boering, K. A.

    2016-02-01

    Measurements of the 14C content of carbon dioxide in air collected by high-altitude balloon flights in 2003-2005 reveal the contemporary radiocarbon distribution in the northern midlatitude stratosphere, four decades after the Limited Test Ban Treaty restricted atmospheric testing of nuclear weapons. Comparisons with results from a 3-D chemical-transport model show that the 14CO2 distribution is now largely governed by the altitude/latitude dependence of the natural cosmogenic production rate, stratospheric transport, and propagation into the stratosphere of the decreasing radiocarbon trend in tropospheric CO2 due to fossil fuel combustion. From the observed correlation of 14CO2 with N2O mixing ratios, an annual global mean net flux of 14CO2 to the troposphere of 1.6(±0.4) × 1017‰ mol CO2 yr-1 and a global production rate of 2.2(±0.6) × 1026 atoms 14C yr-1 are empirically derived. The results also indicate that contemporary 14CO2 observations provide highly sensitive diagnostics for stratospheric transport and residence times in models.

  17. Measurements and modeling of contemporary radiocarbon in the stratosphere

    SciTech Connect

    Kanu, A. M.; Comfort, L. L.; Guilderson, T. P.; Cameron-Smith, P. J.; Bergmann, D. J.; Atlas, E. L.; Schauffler, S.; Boering, K. A.

    2016-01-29

    Measurements of the 14C content of carbon dioxide in air collected by high-altitude balloon flights in 2003–2005 reveal the contemporary radiocarbon distribution in the northern midlatitude stratosphere, four decades after the Limited Test Ban Treaty restricted atmospheric testing of nuclear weapons. Comparisons with results from a 3-D chemical-transport model show that the 14CO2 distribution is now largely governed by the altitude/latitude dependence of the natural cosmogenic production rate, stratospheric transport, and propagation into the stratosphere of the decreasing radiocarbon trend in tropospheric CO2 due to fossil fuel combustion. From the observed correlation of 14CO2 with N2O mixing ratios, an annual global mean net flux of 14CO2 to the troposphere of 1.6(±0.4) × 1017‰ mol CO2 yr–1 and a global production rate of 2.2(±0.6) × 1026 atoms 14C yr–1 are empirically derived. Furthermore, the results also indicate that contemporary 14CO2 observations provide highly sensitive diagnostics for stratospheric transport and residence times in models.

  18. Measurements and modeling of contemporary radiocarbon in the stratosphere

    DOE PAGES

    Kanu, A. M.; Comfort, L. L.; Guilderson, T. P.; ...

    2016-01-29

    Measurements of the 14C content of carbon dioxide in air collected by high-altitude balloon flights in 2003–2005 reveal the contemporary radiocarbon distribution in the northern midlatitude stratosphere, four decades after the Limited Test Ban Treaty restricted atmospheric testing of nuclear weapons. Comparisons with results from a 3-D chemical-transport model show that the 14CO2 distribution is now largely governed by the altitude/latitude dependence of the natural cosmogenic production rate, stratospheric transport, and propagation into the stratosphere of the decreasing radiocarbon trend in tropospheric CO2 due to fossil fuel combustion. From the observed correlation of 14CO2 with N2O mixing ratios, an annualmore » global mean net flux of 14CO2 to the troposphere of 1.6(±0.4) × 1017‰ mol CO2 yr–1 and a global production rate of 2.2(±0.6) × 1026 atoms 14C yr–1 are empirically derived. Furthermore, the results also indicate that contemporary 14CO2 observations provide highly sensitive diagnostics for stratospheric transport and residence times in models.« less

  19. Influence of thermal treatments on radiocarbon dating of groundwater samples

    NASA Astrophysics Data System (ADS)

    Stanciu, Iuliana Madalina; Sava, Tiberiu Bogdan; Pacesila, Doru Gheorghe; Gaza, Oana; Simion, Corina Anca; Stefan, Bianca Maria; Sava, Gabriela Odilia; Ghita, Dan Gabriel; Mosu, Vasile

    2017-06-01

    Radiocarbon measurements of dissolved inorganic carbon (DIC) in water provides information about the formation of oceanic circulation of the water volumes, the hydrogeological systems, and also valuable information can be gained about the aquifer storage and the degree of containment relative to the surface waters. Radiocarbon dating refers to the determination of small quantities of the naturally occurring carbon 14 in the water, which can be integrated in the groundwater mass through the gaseous CO2, carbonaceous deposits dissolved by water and organic remains. The aim of this study is to investigate the influence of the temperature and pressure over the amount of each isotope of carbon during the sample preparation stage. The first step was to evaporate several underground water samples at 65°C under different conditions until the carbonates were obtained, then the CO2 was extracted with orto-phosphoric acid and transformed to graphite. The second step was to obtain graphite from an untreated water sample. Finally, the samples were measured with the 1MV Cockcroft-Walton Tandetron Accelerator by Accelerator Mass Spectrometry.

  20. Initial Measurements of Radiocarbon In Atmospheric Formaldehyde at Narragansett, RI

    NASA Astrophysics Data System (ADS)

    Shen, H.; Heikes, B. G.; Xu, L.; McNichol, A. P.; Olson, J. R.

    2008-12-01

    Formaldehyde is an intermediate in the atmospheric oxidation of nearly every volatile organic compound (VOC) and is important to odd-hydrogen radicals and ozone chemistry. It is directly observed from space and its distributions are used to constrain biogenic emissions of VOCs, specifically isoprene. The relative contribution of fossil VOCs and biogenic VOCs to formaldehyde, to isoprene emission estimates and subsequently to ozone and oxidant chemistry is expected to vary seasonally and spatially due to VOC speciation, emission patterns, and reactivity. The radiocarbon, 14C, content of formaldehyde is useful in assessing the relative contributions of fossil and biogenic VOC groups to formaldehyde. We report a compound specific radiocarbon analysis (CSRA) method for formaldehyde based upon gaseous formaldehyde collection, derivatization to thiazolidine, preparative capillary gas chromatography separation, and AMS analysis. Ambient measurements from Narragansett, RI, made in winter and summer 2007 are presented. On 11 of 13 samples, we find 80 to >95% of the collected formaldehyde is of fossil origin and, contrary to our initial hypothesis, we see no seasonal shift in proportion. The remaining 2 samples, one each from winter and summer, are 30-40% biogenic carbon. The measurements are interpreted considering fossil-biogenic source attribution and local transport conditions and contrasted with prior measurements from Nova Scotia. Further, CSRA measurement of acetaldehyde is feasible with the method.

  1. Marine radiocarbon reservoir age simulations for the past 50000 years

    NASA Astrophysics Data System (ADS)

    Butzin, Martin; Köhler, Peter; Lohmann, Gerrit

    2016-04-01

    We present simulations of marine radiocarbon reservoir ages using the ocean general circulation model LSG-HAMOCC2s, and evaluate the results with Marine13 raw data records. Our model considers various climatic background states. Radiocarbon cycle boundary conditions are atmospheric Δ14C values according to IntCal13, a recent atmospheric CO2 reconstruction, and spatially variable concentrations of dissolved inorganic carbon derived from marine carbon cycle simulations. Our model reasonably agrees with glacial marine Δ14C records but indicates reservoir ages varying with time, different to the invariant reservoir age corrections applied to the observations and to Marine13. Modelled global-mean reservoir ages are in the range 400-800 years compared to the invariant Marine13 value of 405 years. Self-consistent simulations involving the Cariaco Basin record (which is the most continuous marine record contributing to IntCal13 for periods prior to about 30 kyears) amplify the temporal reservoir age variability with global-mean values of about 350-850 years, and improve the agreement with Δ14C observations in some areas.

  2. Radiocarbon age modeling: dissolution, bioturbation and sediment redistribution

    NASA Astrophysics Data System (ADS)

    Mekik, F.

    2012-12-01

    We generated radiocarbon dates for whole and fragmented planktonic foraminifer tests (by several species) from a series of core tops which have experienced little dissolution from two depth transects (Rio Grande Rise - RIO and Ontong Java Plateau - OJP) and from down core records from three tropical Pacific cores with significantly different sediment accumulation rates. We also generated new radiocarbon data from both whole Globorotalia menardii shells and its fragments within the same sediments in order to test the robustness of a calcite dissolution proxy, the G. menardii Fragmentation Index (MFI). Our data reveal that the ages of all sediment components increase with increasing dissolution. This is most easily observable on RIO where the age offset between the shallowest samples and deepest samples is ~5 ka, while the mixing ages of the cores are ~1.9ka. This result is new and significant because previous work has always been in the tropical Pacific where bioturbation and mixing ages are high. Furthermore, two of the 7 core top samples from RIO revealed whole G. menardii shells of Glacial age. This is surprising because G. menardiis have not been reported in sediments from the Atlantic Ocean older than 13,000 years. Lastly, we found that the higher the sediment accumulation rate, the closer the age offset between G. menradii whole shells and its fragments in the same sediments both on RIO and OJP. This is important for the interpretation of down core work with MFI.

  3. Growth rate determinations from radiocarbon in bamboo corals (genus Keratoisis)

    NASA Astrophysics Data System (ADS)

    Farmer, Jesse R.; Robinson, Laura F.; Hönisch, Bärbel

    2015-11-01

    Radiocarbon (14C) measurements are an important tool for determining growth rates of bamboo corals, a cosmopolitan group of calcitic deep-sea corals. Published growth rate estimates for bamboo corals are highly variable, with potential environmental or ecological drivers of this variability poorly constrained. Here we systematically investigate the application of 14C for growth rate determinations in bamboo corals using 55 14C dates on the calcite and organic fractions of six bamboo corals (identified as Keratoisis sp.) from the western North Atlantic Ocean. Calcite 14C measurements on the distal surface of these corals and five previously published bamboo corals exhibit a strong one-to-one relationship with the 14C of dissolved inorganic carbon (DI14C) in ambient seawater (r2=0.98), confirming the use of Keratoisis sp. calcite 14C as a proxy for seawater 14C activity. Radial growth rates determined from 14C age-depth regressions, 14C plateau tuning and bomb 14C reference chronologies range from 12 to 78 μm y-1, in general agreement with previously published radiometric growth rates. We document potential biases to 14C growth rate determinations resulting from water mass variability, bomb radiocarbon, secondary infilling (ontogeny), and growth rate nonlinearity. Radial growth rates for Keratoisis sp. specimens do not correlate with ambient temperature, suggesting that additional biological and/or environmental factors may influence bamboo coral growth rates.

  4. AMS radiocarbon dating of very large Grandidier's baobabs (Adansonia grandidieri)

    NASA Astrophysics Data System (ADS)

    Patrut, Adrian; von Reden, Karl F.; Danthu, Pascal; Leong Pock-Tsy, Jean-Michel; Rakosy, Laszlo; Patrut, Roxana T.; Lowy, Daniel A.; Margineanu, Dragos

    2015-10-01

    The article reports the AMS radiocarbon investigation of the two largest known Adansonia grandidieri specimens. The two baobabs, which are named Tsitakakoike and Pregnant baobab, are located in Southwestern Madagascar, near Andombiro. A third specimen from this area, the House baobab, was also investigated. According to measurements, Tsitakakoike is the biggest individual above ground level of all Adansonia species. The House baobab was selected for its exposed structure, which is identical to the closed ring-shaped structure with false cavities identified by us in large and old Adansonia digitata specimens. According to our research, Tsitakakoike and the Pregnant baobab have multi-stemmed cylindrical trunks which are mainly hollow; the two very large baobabs also possess a ring-shaped structure. The radiocarbon dates of the oldest wood samples collected from the large trunks were 1274 ± 20 BP for Tsitakakoike and 930 ± 20 BP for the Pregnant baobab. According to their original positions and to the architectures of the two A. grandidieri, the ages of Tsitakakoike and Pregnant baobab would be between 1300 and 1500 years. Therefore, A. grandidieri becomes the third Adansonia species with individuals that can live over 1000 years, according to accurate dating results.

  5. Vertebral bomb radiocarbon suggests extreme longevity in white sharks.

    PubMed

    Hamady, Li Ling; Natanson, Lisa J; Skomal, Gregory B; Thorrold, Simon R

    2014-01-01

    Conservation and management efforts for white sharks (Carcharodon carcharias) remain hampered by a lack of basic demographic information including age and growth rates. Sharks are typically aged by counting growth bands sequentially deposited in their vertebrae, but the assumption of annual deposition of these band pairs requires testing. We compared radiocarbon (Δ(14)C) values in vertebrae from four female and four male white sharks from the northwestern Atlantic Ocean (NWA) with reference chronologies documenting the marine uptake of (14)C produced by atmospheric testing of thermonuclear devices to generate the first radiocarbon age estimates for adult white sharks. Age estimates were up to 40 years old for the largest female (fork length [FL]: 526 cm) and 73 years old for the largest male (FL: 493 cm). Our results dramatically extend the maximum age and longevity of white sharks compared to earlier studies, hint at possible sexual dimorphism in growth rates, and raise concerns that white shark populations are considerably more sensitive to human-induced mortality than previously thought.

  6. The role of inter-comparisons in radiocarbon quality assurance

    NASA Astrophysics Data System (ADS)

    Scott, Marian; Cook, Gordon; Naysmith, Philip

    2016-04-01

    Radiocarbon dating is used widely in many geochronology projects as a basis for the creation and testing of chronological constructs. Radiocarbon measurements are by their nature complex and the degree of sample pre-treatment varies considerably depending on the material. Within the UK and Europe, there are a number of well-established laboratories and increasingly, scientists are not just commissioning new dates, but also using statistical modelling of assemblages of dates, perhaps measured in different laboratories, to provide formal date estimates for their investigations. The issue of comparability of measurements (and thus bias, accuracy and precision of measurement) from the diverse laboratories is one which has been the focus of some attention both within the 14C community and the wider user communities for some time. As a result of this but also as part of laboratory benchmarking and quality assurance, the 14C community has undertaken a wide-scale, far-reaching and evolving programme of inter-comparisons, to the benefit of laboratories and users alike. This paper presents the results from the most recent exercise SIRI. The objectives of SIRI included, through choice of material, to contribute to the discussion concerning laboratory offsets and error multipliers in the context of IntCal (the International Calibration Programme) and to gain a better understanding of differences in background derived from a range of infinite age material types.

  7. A new radiocarbon revolution and the dispersal of modern humans in Eurasia.

    PubMed

    Mellars, Paul

    2006-02-23

    Radiocarbon dating has been fundamental to the study of human cultural and biological development over the past 50,000 yr. Two recent developments in the methodology of radiocarbon dating show that the speed of colonization of Europe by modern human populations was more rapid than previously believed, and that their period of coexistence with the preceding Neanderthal was shorter.

  8. A new radiocarbon revolution and the dispersal of modern humans in Eurasia

    NASA Astrophysics Data System (ADS)

    Mellars, Paul

    2006-02-01

    Radiocarbon dating has been fundamental to the study of human cultural and biological development over the past 50,000yr. Two recent developments in the methodology of radiocarbon dating show that the speed of colonization of Europe by modern human populations was more rapid than previously believed, and that their period of coexistence with the preceding Neanderthal was shorter.

  9. Addressing Disparities in Stroke Prevention for Atrial Fibrillation: Educational Opportunities.

    PubMed

    Karcher, Rachel; Berman, Adam E; Gross, Hartmut; Hess, David C; Jauch, Edward C; Viser, Paul E; Solenski, Nina J; Wolf, Andrew M D

    2016-07-01

    Disparities in atrial fibrillation (AF)-related stroke and mortality persist, especially racial disparities, within the US "Stroke Belt." This study identified barriers to optimal stroke prevention to develop a framework for clinician education. A comprehensive educational needs assessment was developed focusing on clinicians within the Stroke Belt. The mixed qualitative-quantitative approach included regional surveys and one-on-one clinician interviews. Identified contributors to disparities included implicit racial biases, lack of awareness of racial disparities in AF stroke risk, and lack of effective multicultural awareness and training. Additional barriers affecting disparities included patient medical mistrust and clinician-patient communication challenges. General barriers included lack of consistency in assessing stroke and anticoagulant-related bleeding risk, underuse of standardized risk assessment tools, discomfort with novel anticoagulants, and patient education deficiencies. Effective cultural competency training is one strategy to reduce disparities in AF-related stroke and mortality by improving implicit clinician bias, addressing medical mistrust, and improving clinician-patient communication.

  10. Source apportionment of elevated wintertime PAHs by compound-specific radiocarbon analysis

    NASA Astrophysics Data System (ADS)

    Sheesley, R. J.; Kruså, M.; Krecl, P.; Johansson, C.; Gustafsson, Ã.-.

    2009-05-01

    Natural abundance radiocarbon analysis facilitates distinct source apportionment between contemporary biomass/biofuel (14C "alive") versus fossil fuel (14C "dead") combustion. Here, the first compound-specific radiocarbon analysis (CSRA) of atmospheric polycyclic aromatic hydrocarbons (PAHs) was demonstrated for a set of samples collected in Lycksele, Sweden a small town with frequent episodes of severe atmospheric pollution in the winter. Renewed interest in using residential wood combustion (RWC) means that this type of seasonal pollution is of increasing concern in many areas. Five individual/paired PAH isolates from three pooled fortnight-long filter collections were analyzed by CSRA: phenanthrene, fluoranthene, pyrene, benzo[b+k]fluoranthene and indeno[cd]pyrene plus benzo[ghi]perylene; phenanthrene was the only compound also analyzed in the gas phase. The measured Δ14C for PAHs spanned from -138.3‰ to 58.0‰. A simple isotopic mass balance model was applied to estimate the fraction biomass (fbiomass) contribution, which was constrained to 71-87% for the individual PAHs. Indeno[cd]pyrene plus benzo[ghi]perylene had an fbiomass of 71%, while fluoranthene and phenanthrene (gas phase) had the highest biomass contribution at 87%. The total organic carbon (TOC, defined as carbon remaining after removal of inorganic carbon) fbiomass was estimated to be 77%, which falls within the range for PAHs. This CSRA data of atmospheric PAHs established that RWC is the dominating source of atmospheric PAHs to this region of the boreal zone with some variations among RWC contributions to specific PAHs.

  11. Radiocarbon Analysis Source Apportionment of Fossil and Modern Atmospheric Carbon from DISCOVER-AQ Houston

    NASA Astrophysics Data System (ADS)

    Ortiz, S. M.; Yoon, S.; Barrett, T. E.; Usenko, S.; Sheesley, R. J.

    2015-12-01

    DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Resolved Observations Relevant to Air Quality) is a sampling campaign aimed to monitor regional atmospheric pollutants within a collection of cities across the United States. In September 2013, ground-based air samplers were placed selectively to represent the city of Houston: Moody Tower (downtown; urban) and Manvel Croix (southern; suburb), Conroe (far north; suburb) and La Porte (east; urban industrial), with the goal of understanding particulate matter sources and composition and exposure in urban communities. Radiocarbon analysis was conducted on TSP (total suspended particulate matter) and PM2.5 (particulate matter less than 2.5 μm in aerodynamic diameter) from ground-based samplers. Radiocarbon is used to determine the contributions of contemporary and fossil sources to carbonaceous aerosol in Houston. Contemporary sources of atmospheric carbon in TSP and PM2.5 include primary biogenic emissions, biomass combustion and SOA produced in the atmosphere from biogenic- and biomass combustion-derived volatile organic carbon. Fossil sources of atmospheric carbon in PM2.5 and TSP include all types of primary fossil fuel combustion and SOA produced in the atmosphere from fossil-derived volatile organic carbon. Results from the last week of the campaign, September 21-28th, displayed a PM2.5 contemporary carbon fraction of 48-78% for Moody Tower, 59-86% for Manvel Croix, 66-89% for Conroe. Ambient TSP had contemporary carbon fractions of 51-65% for Moody Tower and 51-83% for La Porte.

  12. Empirical calibrated radiocarbon sampler: a tool for incorporating radiocarbon-date and calibration error into Bayesian phylogenetic analyses of ancient DNA.

    PubMed

    Molak, Martyna; Suchard, Marc A; Ho, Simon Y W; Beilman, David W; Shapiro, Beth

    2015-01-01

    Studies of DNA from ancient samples provide a valuable opportunity to gain insight into past evolutionary and demographic processes. Bayesian phylogenetic methods can estimate evolutionary rates and timescales from ancient DNA sequences, with the ages of the samples acting as calibrations for the molecular clock. Sample ages are often estimated using radiocarbon dating, but the associated measurement error is rarely taken into account. In addition, the total uncertainty quantified by converting radiocarbon dates to calendar dates is typically ignored. Here, we present a tool for incorporating both of these sources of uncertainty into Bayesian phylogenetic analyses of ancient DNA. This empirical calibrated radiocarbon sampler (ECRS) integrates the age uncertainty for each ancient sequence over the calibrated probability density function estimated for its radiocarbon date and associated error. We use the ECRS to analyse three ancient DNA data sets. Accounting for radiocarbon-dating and calibration error appeared to have little impact on estimates of evolutionary rates and related parameters for these data sets. However, analyses of other data sets, particularly those with few or only very old radiocarbon dates, might be more sensitive to using artificially precise sample ages and should benefit from use of the ECRS.

  13. A coupled model for carbon and radiocarbon evolution during the last deglaciation

    NASA Astrophysics Data System (ADS)

    Mariotti, Véronique; Paillard, Didier; Bopp, Laurent; Roche, Didier M.; Bouttes, Nathaëlle

    2016-02-01

    Changes in the ventilation of the Southern Ocean are thought to play an important role on deglacial carbon and radiocarbon evolution but have not been tested within a coupled climate-carbon model. Here we present such a simulation based on a simple scenario of transient deglacial sinking of brines—sea ice salt rejections—around Antarctica, which modulates Southern Ocean ventilation. This experiment is able to reproduce deglacial atmospheric changes in carbon and radiocarbon and also ocean radiocarbon records measured in the Atlantic, Southern, and Pacific Oceans. Simulated for the first time in a fully coupled climate-carbon model of intermediate complexity including radiocarbon, our modeling results suggest that the deglacial changes in atmospheric carbon dioxide and radiocarbon were achieved by means of a breakdown in the glacial brine-induced stratification of the Southern Ocean.

  14. Radiocarbon dating of VIRI bone samples using ultrafiltration

    NASA Astrophysics Data System (ADS)

    Minami, Masayo; Yamazaki, Kana; Omori, Takayuki; Nakamura, Toshio

    2013-01-01

    Ultrafiltration can effectively remove low-molecular-weight (LMW) contaminants from bone gelatin to extract high-molecular-weight (HMW) proteins that are derived from original bone collagen, though it cannot remove HMW collagen crosslinked with humic acids. Therefore, ultrafiltration is often used to obtain more accurate 14C dates of bones. However, ultrafiltration may introduce new contaminants to bone gelatins, mainly from ultrafilters used. To study the effects of ultrafiltration on 14C age, we analyzed the C/N ratio, δ13CPDB and δ15NAIR values, and 14C ages of acid-soluble bone collagen obtained by decalcification, gelatin extracted from acid-insoluble bone collagen, and the HMW gelatin and LMW fractions produced during ultrafiltration of the extracted gelatin. Bone samples from the Fifth International Radiocarbon Intercomparison (VIRI) were used: VIRI-E (mammoth), -F (horse), -G (human), and -I (whale). In this study, carbon and nitrogen content and gelatin yields were used to evaluate collagen preservation in the VIRI bone samples. Radiocarbon ages, δ13CPDB and δ15NAIR values of unfiltered and HMW gelatins were obtained and compared with the published consensus values. The LMW fraction was found to exhibit different values from those of the other fractions, indicating the possible presence of extraneous contamination. The Vivaspin™ 6 ultrafilters used in this study were analyzed and radiocarbon dated both before and after cleaning. We present evidence to suggest that LMW fraction contaminants could be derived from the ultrafilters rather than humic substances. Excessively long ultrafiltration time was suspected to have contaminated the bone samples with material from the ultrafilter, because those samples exhibited older 14C ages than did those filtered for shorter durations. The results in this study indicate that 14C ages of unfiltered gelatin extracted from well-preserved bones can be sufficiently accurate, and that care should be taken not to

  15. Approaching Health Disparities from a Population Perspective: The NIH Centers for Population Health and Health Disparities

    USDA-ARS?s Scientific Manuscript database

    Addressing health disparities has been a national challenge for decades. The NIH-sponsored Centers for Population Health and Health Disparities (CPHHDs) represent the first federal initiative to support transdisciplinary multilevel research on the determinants of health disparities. Using preliminar...

  16. Disparity channels in early vision

    PubMed Central

    Roe, AW; Parker, AJ; Born, RT; DeAngelis, GC

    2008-01-01

    The last decade has seen a dramatic increase in our knowledge of the neural basis of stereopsis. New cortical areas have been found to represent binocular disparities, new representations of disparity information (e.g., relative disparity signals) have been uncovered, the first topographic maps of disparity have been measured, and the first causal links between neural activity and depth perception have been established. Equally exciting is the finding that training and experience affects how signals are channeled through different brain areas, a flexibility that may be crucial for learning, plasticity, and recovery of function. The collective efforts of several laboratories have established stereo vision as one of the most productive model systems for elucidating the neural basis of perception. Much remains to be learned about how the disparity signals that are initially encoded in primary visual cortex are routed to and processed by extrastriate areas to mediate the diverse capacities of 3D vision that enhance our daily experience of the world. PMID:17978018

  17. Disparity channels in early vision.

    PubMed

    Roe, Anna W; Parker, Andrew J; Born, Richard T; DeAngelis, Gregory C

    2007-10-31

    The past decade has seen a dramatic increase in our knowledge of the neural basis of stereopsis. New cortical areas have been found to represent binocular disparities, new representations of disparity information (e.g., relative disparity signals) have been uncovered, the first topographic maps of disparity have been measured, and the first causal links between neural activity and depth perception have been established. Equally exciting is the finding that training and experience affects how signals are channeled through different brain areas, a flexibility that may be crucial for learning, plasticity, and recovery of function. The collective efforts of several laboratories have established stereo vision as one of the most productive model systems for elucidating the neural basis of perception. Much remains to be learned about how the disparity signals that are initially encoded in primary visual cortex are routed to and processed by extrastriate areas to mediate the diverse capacities of three-dimensional vision that enhance our daily experience of the world.

  18. Single amino acid radiocarbon dating of Upper Paleolithic modern humans.

    PubMed

    Marom, Anat; McCullagh, James S O; Higham, Thomas F G; Sinitsyn, Andrey A; Hedges, Robert E M

    2012-05-01

    Archaeological bones are usually dated by radiocarbon measurement of extracted collagen. However, low collagen content, contamination from the burial environment, or museum conservation work, such as addition of glues, preservatives, and fumigants to "protect" archaeological materials, have previously led to inaccurate dates. These inaccuracies in turn frustrate the development of archaeological chronologies and, in the Paleolithic, blur the dating of such key events as the dispersal of anatomically modern humans. Here we describe a method to date hydroxyproline found in collagen (~10% of collagen carbon) as a bone-specific biomarker that removes impurities, thereby improving dating accuracy and confidence. This method is applied to two important sites in Russia and allows us to report the earliest direct ages for the presence of anatomically modern humans on the Russian Plain. These dates contribute considerably to our understanding of the emergence of the Mid-Upper Paleolithic and the complex suite of burial behaviors that begin to appear during this period.

  19. Accelerator radiocarbon dating of evidence for prehistoric horticulture in Illinois

    USGS Publications Warehouse

    Conard, N.; Asch, D.L.; Asch, N.B.; Elmore, D.; Gove, H.; Rubin, M.; Brown, J.A.; Wiant, M.D.; Farnsworth, K.B.; Cook, T.G.

    1984-01-01

    With the development of direct detection radiocarbon dating, which uses an accelerator as part of a highly selective mass spectrometer, it is now possible to determine the age of milligram samples of organic materials1-5. One application of accelerator dating is in evaluating scanty, sometimes controversial evidence for early horticulture throughout the world. We have now used the technique to date small samples of carbonized, cultivated plant remains from archaeological sites in Illinois. The results, reported here, establish (1) that squash was introduced by 7,000 yr ago, 2,500 yr before eastern North American records previously reported; (2) that horticulture involving indigenous plants had begun by 4,000 BP in eastern North America with domestication of Iva annua, a small-seeded annual; (3) that anomalous discoveries of Archaic period maize represent contaminants; and (4) that introduction of maize by initial Middle Woodland times (~2,000 BP) is questionable.

  20. Widening economic & social disparities: implications for India.

    PubMed

    Kurian, N J

    2007-10-01

    India is often characterized as an emerging economic super power. The huge demographic dividend, the high quality engineering and management talent, the powerful Indian diaspora and the emerging Indian transnational--kneeling the optimism. In contrast, there is another profile of India which is rather gloomy. This is the country with the largest number of the poor, illiterates and unemployed in the world. High infant mortality, morbidity and widespread anaemia among women and children continue. India suffers from acute economic and social disparities. This article addresses four dimensions of such disparities, viz. regional, rural-urban, social, and gender. There is empirical evidence to indicate that during the last two decades all these disparities have been increasing. As a result of economic reforms, the southern and western States experienced accelerated economic and social development as compared to northern and eastern States. This has led to widening gap in income, poverty and other indicators of development between the two regions. Rural-urban divide also widened in the wake of reforms. While large and medium cities experience unprecedented economic prosperity, the rural areas experience economic stagnation. As a result, there is widespread agrarian distress which results in farmers' suicide and rural unrest. Socially backward sections, especially scheduled castes and tribes (SCs and STs) have gained little from the new prosperity which rewards disproportionately those with assets, skills and higher education. STs have often been victims of development as a result of displacement. The gender gap in social and economic status, traditionally more in India as compared to other societies; has further widened by the economic reforms and globalization. The approach paper to the Eleventh Plan stresses the importance of more inclusive economic growth. It emphasizes the need for bridging the divides discussed in this article. Unless these are achieved in a time

  1. Radiocarbon measurements of black carbon in aerosols and ocean sediments

    NASA Astrophysics Data System (ADS)

    Masiello, C. A.; Druffel, E. R. M.; Currie, L. A.

    2002-03-01

    Black carbon (BC) is the combustion-altered, solid residue remaining after biomass burning and fossil fuel combustion. Radiocarbon measurements of BC provide information on the residence time of BC in organic carbon pools like soils and sediments, and also provide information on the source of BC by distinguishing between fossil fuel and biomass combustion byproducts. We have optimized dichromate-sulfuric acid oxidation for the measurement of radiocarbon in BC. We also present comparisons of BC 14C measurements on NIST aerosol SRM 1649a with previously published bulk aromatic 14C measurements and individual polycyclic aromatic hydrocarbon (PAH) 14C measurements on the same NIST standard. Dichromate-sulfuric acid oxidation belongs to the chemical class of BC measurement methods, which rely on the resistance of some forms of BC to strong chemical oxidants. Dilute solutions of dichromate-sulfuric acid degrade BC and marine-derived carbon at characteristic rates from which a simple kinetic formula can be used to calculate concentrations of individual components (Wolbach and Anders, 1989). We show that: (1) dichromate-sulfuric acid oxidation allows precise, reproducible 14C BC measurements; (2) kinetics calculations give more precise BC yield information when performed on a % OC basis (vs. a % mass basis); (3) kinetically calculated BC concentrations are similar regardless of whether the oxidation is performed at 23°C or 50°C; and (4) this method yields 14C BC results consistent with previously published aromatic 14C data for an NIST standard. For the purposes of intercomparison, we report % mass and carbon results for two commercially available BC standards. We also report comparative data from a new thermal method applied to SRM 1649a, showing that thermal oxidation of this material also follows the simple kinetic sum of exponentials model, although with different time constants.

  2. Using accelerator mass spectrometry for radiocarbon dating of textiles

    SciTech Connect

    Jull, A.J.T.

    1997-12-01

    Since 1981 we have operated an NSF Accelerator Mass Spectrometry (AMS) Facility at the University of Arizona. The AMS method allows us to use very small samples of carbon, <1 mg for radiocarbon dating in contrast to earlier counting techniques. This has opened a vast array of applications of radiocarbon dating that was difficult to do before AMS because of sample size limitations of decay counting. Some of the many applications of AMS include paleoclimatic studies, archaeological research and the age of first settlement of North America by man, dating of art works and artifacts, fall times and terrestrial residence ages of meteorites, production of {sup 14}C in lunar samples by galactic and solar cosmic rays, studies of in situ {sup 14}C produced by cosmic ray spallation in rocks and ice, and studies of {sup 14}C in groundwater dissolved inorganic carbon and dissolved organic carbon. At our laboratory, we have also successfully applied AMS {sup 14}C to dating of many types of textiles, including silks and linens, art works, documents and artifacts fabricated from wood, parchment, ivory, and bone. The results for many of these samples are often important in questions of the authenticity of these works of art and artifacts. Our studies have encompassed a wide range of art works ranging from the Dead Sea Scrolls, the Shroud of Turin, and the Chinese silk trade to the works of Raphael, Rembrandt, and Picasso. Recently, we also dated the Vinland Map, a controversial document that shows the eastern coast of North America apparently using information from Viking voyages.

  3. The radiocarbon signature of microorganisms in the mesopelagic ocean

    PubMed Central

    Hansman, Roberta L.; Griffin, Sheila; Watson, Jordan T.; Druffel, Ellen R. M.; Ingalls, Anitra E.; Pearson, Ann; Aluwihare, Lihini I.

    2009-01-01

    Several lines of evidence indicate that microorganisms in the meso- and bathypelagic ocean are metabolically active and respiring carbon. In addition, growing evidence suggests that archaea are fixing inorganic carbon in this environment. However, direct quantification of the contribution from deep ocean carbon sources to community production in the dark ocean remains a challenge. In this study, carbon flow through the microbial community at 2 depths in the mesopelagic zone of the North Pacific Subtropical Gyre was examined by exploiting the unique radiocarbon signatures (Δ14C) of the 3 major carbon sources in this environment. The radiocarbon content of nucleic acids, a biomarker for viable cells, isolated from size-fractionated particles (0.2–0.5 μm and >0.5 μm) showed the direct incorporation of carbon delivered by rapidly sinking particles. Most significantly, at the 2 mesopelagic depths examined (670 m and 915 m), carbon derived from in situ autotrophic fixation supported a significant fraction of the free-living microbial community (0.2–0.5 μm size fraction), but the contribution of chemoautotrophy varied markedly between the 2 depths. Results further showed that utilization of the ocean's largest reduced carbon reservoir, 14C-depleted, dissolved organic carbon, was negligible in this environment. This isotopic portrait of carbon assimilation by the in situ, free-living microbial community, integrated over >50,000 L of seawater, implies that recent, photosynthetic carbon is not always the major carbon source supporting microbial community production in the mesopelagic realm. PMID:19366673

  4. Atmosphere-ocean gas exchange based on radiocarbon data

    NASA Astrophysics Data System (ADS)

    Byalko, Alexey

    2014-05-01

    In recent decades, the intensity of global atmospheric convection has accelerated faster than climate warming; it is possible to judge this process from indirect data. Increasing ocean salinity contrasts provide evidence that evaporation has intensified [1]; sea surface wind velocities and wave heights have increased [2]. The CO2 gas exchange between the atmosphere and ocean must also simultaneously increase. Monthly measurements of atmospheric CO2 concentration have been published since 1958 [3], but directly measuring its fluxes from the atmosphere to the ocean and back is hardly possible. We show they can be reconstructed from 14C isotope concentration data. In the past century, two processes influenced the atmospheric 14C concentration in opposite directions: burning fossil fuels and testing nuclear weapons in the atmosphere. We compare the gas exchange theory with measurements of radiocarbon content in the atmosphere [4—6], which allows assessing the gas exchange quantitatively for the ocean to atmosphere and atmosphere to ocean fluxes separately for period 1960—2010 [7]. References 1. Durack P. J. and Wijffels S. E., J. Climate 23, 4342 (2010). 2. Young I. R., Sieger S., and Babanin A.V., Science 332, 451 (2011). 3. NOAA Earth System Research Laboratory Data: ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt. 4. Nydal R., Lövseth K. // J. Geophys. Res. 1983. V. 88. P. 3579. 5. Levin I., Kromer B. // Radiocarbon. 1997. V. 39. P. 205. 6. Miller J.B., Lehman S.J., Montzka S.A., et al. // J. Geophys. Res. 2012. V. 117. D08302. 7. Byalko A.V. Doklady Physics, 2013. V. 58, 267-271.

  5. Environmental Health Disparities in Housing

    PubMed Central

    2011-01-01

    The physical infrastructure and housing make human interaction possible and provide shelter. How well that infrastructure performs and which groups it serves have important implications for social equity and health. Populations in inadequate housing are more likely to have environmental diseases and injuries. Substantial disparities in housing have remained largely unchanged. Approximately 2.6 million (7.5%) non-Hispanic Blacks and 5.9 million Whites (2.8%) live in substandard housing. Segregation, lack of housing mobility, and homelessness are all associated with adverse health outcomes. Yet the experience with childhood lead poisoning in the United States has shown that housing-related disparities can be reduced. Effective interventions should be implemented to reduce environmental health disparities related to housing. PMID:21551378

  6. Socioeconomic Disparities in Health Behaviors

    PubMed Central

    Pampel, Fred C.; Krueger, Patrick M.; Denney, Justin T.

    2011-01-01

    The inverse relationships between socioeconomic status (SES) and unhealthy behaviors such as tobacco use, physical inactivity, and poor nutrition have been well demonstrated empirically but encompass diverse underlying causal mechanisms. These mechanisms have special theoretical importance because disparities in health behaviors, unlike disparities in many other components of health, involve something more than the ability to use income to purchase good health. Based on a review of broad literatures in sociology, economics, and public health, we classify explanations of higher smoking, lower exercise, poorer diet, and excess weight among low-SES persons into nine broad groups that specify related but conceptually distinct mechanisms. The lack of clear support for any one explanation suggests that the literature on SES disparities in health and health behaviors can do more to design studies that better test for the importance of the varied mechanisms. PMID:21909182

  7. Constraint on radiocarbon age correction in Lake Biwa environment from the middle to late Holocene

    NASA Astrophysics Data System (ADS)

    Miyata, Y.; Minami, M.; Onbe, S.; Sakamoto, M.; Nakamura, T.; Imamura, M.

    2013-01-01

    Using data from previous studies and newly collected data, we compared the measured radiocarbon ages of molluscan shells, common reed (Phragmites australis) and pine needles (Pinus thunbergii) collected in 1966, 1970, 1990 and 2008 at Lake Biwa in Japan, and of archaeological samples, to examine radiocarbon reservoir effects at Lake Biwa. We also tested for differences in the radiocarbon reservoir effect between species and locations in the lake. The effects of nuclear bomb tests conducted in the 1950s and 1960s are clear, the offset between atmospheric 14C and the Lake Biwa freshwater 14C is larger for this period because the atmospheric 14C is so high. The semiclosed Lake Biwa system is in dynamic equilibrium with the atmosphere, resulting in the 14C content of the water following the changes in atmospheric 14C caused by nuclear testing. The shells collected after 1990 had radiocarbon ages that were 330-450 14C years older than those of the coeval atmosphere. The apparent differences in radiocarbon age (about 300 14C years) between shell fossils and wood samples excavated from the same layer of the submerged Awazu shell midden at Lake Biwa suggest that the radiocarbon reservoir effect also existed in the middle Holocene (the Middle Jomon period, about 5000 years ago). Because the present-day average residence time of Lake Biwa water is 3-6 years, its direct influence on the radiocarbon reservoir effect is small, which suggests that old carbon has been supplied into Lake Biwa.

  8. Radiocarbon dating from 40 to 60 ka BP at Border Cave, South Africa

    NASA Astrophysics Data System (ADS)

    Bird, M. I.; Fifield, L. K.; Santos, G. M.; Beaumont, P. B.; Zhou, Y.; di Tada, M. L.; Hausladen, P. A.

    2003-04-01

    We present 21 radiocarbon dates on 19 charcoal samples from the sedimentary sequence preserved in Border Cave, South Africa. The background radiocarbon activity for charcoal from the cave was determined to be 0.050±0.018 percent modern carbon, from the analysis of a radiocarbon-dead sample from unit 5WA. Radiocarbon ages for individual samples ranged from 25.2 to >58.2 ka BP. The error-weighted mean ages for successively older strata are 38.5+0.85/-0.95 ka BP for unit 1WA, 50.2+1.1/-1.0 ka BP for units 2BS.LR.A and 2BS.LR.B, 56.5+2.7/-2.0 ka BP for unit 2BS.LR.C and 59.2+3.4/-2.4 ka BP for unit 2WA. This radiocarbon chronology is consistent with independent chronologies derived from electron spin resonance and amino acid racemization dating. The results therefore provide further evidence that radiocarbon dating of charcoal by the ABOX-SC technique can yield reliable radiocarbon ages beyond 40 ka BP. They also imply that Border Cave 5, a modern human mandible, predates >58.2 ka BP and that the Middle Stone Age (Mode 3)—Later Stone Age (Mode 5) transition of Border Cave was largely effected between ˜56.5 and ˜41.6 ka ago.

  9. Variability in radiocarbon ages of biochemical compound classes of high molecular weight dissolved organic matter in estuaries

    NASA Astrophysics Data System (ADS)

    Wang, Xu-Chen; Callahan, Julie; Chen, Robert F.

    2006-06-01

    High molecular weight dissolved organic matter (HMW-DOM, >1000 Da) represents a major fraction (>30%) of dissolved organic carbon (DOC) in the ocean and thus plays an important role in the global biogeochemical cycling of carbon and many other elements. Its organic sources and formation mechanisms, however, are still not well understood especially in estuarine and coastal regions where multiple natural and anthropogenic sources contribute to total HMW-DOM. In this paper we report our measurements of natural radiocarbon ( 14C) abundances and stable carbon isotope ( 13C) compositions of the major biochemical compound classes: amino acids, carbohydrates and lipids separated from eight HMW-DOM samples collected from five US estuaries as part of our on-going study of sources, distribution and transport of chromophoric dissolved organic matter (CDOM) in estuarine and coastal waters. Distinct differences in both 14C and 13C values were found among the bulk HMW-DOM samples as well as the individual compound classes. Radiocarbon ages of the major compound classes varied by as much as 27,000 years in a single sample. The calculated average radiocarbon ages of the compound fractions of HMW-DOM indicate that the total lipid fraction is very "old", while the acid-insoluble fraction is slightly younger. Total amino acid and carbohydrate fractions, however, have relatively modern apparent 14C ages. The significant variability in 14C ages among the compound classes indicates not only multiple organic carbon sources but also different formation and turnover pathways controlling the cycling of different biochemical components of HMW-DOM in estuarine and coastal waters.

  10. Intracavity OptoGalvanic Spectroscopy not suitable for ambient level radiocarbon detection.

    PubMed

    Paul, Dipayan; Meijer, Harro A J

    2015-09-01

    IntraCavity OptoGalvanic Spectroscopy as a radiocarbon detection technique was first reported by the Murnick group at Rutgers University, Newark, NJ, in 2008. This technique for radiocarbon detection was presented with tremendous potentials for applications in various fields of research. Significantly cheaper, this technique was portrayed as a possible complementary technique to the more expensive and complex accelerator mass spectrometry. Several groups around the world started developing this technique for various radiocarbon related applications. The IntraCavity OptoGalvanic Spectroscopy setup at the University of Groningen was constructed in 2012 in close collaboration with the Murnick group for exploring possible applications in the fields of radiocarbon dating and atmospheric monitoring. In this paper we describe a systematic evaluation of the IntraCavity OptoGalvanic Spectroscopy setup at Groningen for radiocarbon detection. Since the IntraCavity OptoGalvanic Spectroscopy setup was strictly planned for dating and atmospheric monitoring purposes, all the initial experiments were performed with CO2 samples containing contemporary levels and highly depleted levels of radiocarbon. Because of recurring failures in differentiating the two CO2 samples, with the radiocarbon concentration 3 orders of magnitude apart, CO2 samples containing elevated levels of radiocarbon were prepared in-house and experimented with. All results obtained thus far at Groningen are in sharp contrast to the results published by the Murnick group and rather support the results put forward by the Salehpour group at Uppsala University. From our extensive test work, we must conclude that the method is unsuited for ambient level radiocarbon measurements, and even highly enriched CO2 samples yield insignificant signal.

  11. A case of early Wisconsinan ;over-chill;: New radiocarbon evidence for early extirpation of western camel (Camelops hesternus) in eastern Beringia

    NASA Astrophysics Data System (ADS)

    Zazula, Grant D.; MacPhee, Ross D. E.; Southon, John; Nalawade-Chavan, Shweta; Reyes, Alberto V.; Hewitson, Susan; Hall, Elizabeth

    2017-09-01

    There are comparatively few fossils that document the presence of the Pleistocene western camel (Camelops hesternus) in the unglaciated regions of Alaska and Yukon, northwestern North America (eastern Beringia). It has been previously reported on the basis of stratigraphic and radiocarbon data that this species was present within this region from the Sangamonian interglaciation (Marine Isotope Stage (MIS) 5) through the Last Glacial Maximum (LGM, MIS 2). However, the continued presence of western camel through the LGM is at odds with its ecological preferences as inferred from more southerly parts of the continent. Here we report 43 new radiocarbon dates on 34 western camel fossils from Alaska and Yukon, including specimens that have been dated previously. To minimize exogenous carbon contamination, we utilized either ultrafiltered collagen or single amino acid (hydroxyproline) methodologies in conducting the analyses. All samples, including previously reported specimens with finite ages, yielded ages that were either non-finite or close to the effective limit of radiocarbon dating. These results indicate that dates implying local presence of western camels in Alaska and Yukon during full-glacial conditions of MIS 2 are erroneous by as much as several tens of millennia, probably because of carbon contamination from glue or varnish used in fossil preparation and conservation. The revised radiocarbon chronology, together with other evidence, indicates that western camels were only able to occupy eastern Beringia only during Pleistocene interglaciations such as MIS 5, when forests and shrublands became the dominant regional biomes. The subsequent transition to cold, arid full-glacial conditions during the early Wisconsinan glaciation (MIS 4) around 75 000 years ago created unfavorable environmental conditions, eliminated browse, and led to their local extirpation in eastern Beringia. After their complete population loss in the Arctic and Subarctic, the range of

  12. Optical Detection and Quantification of Radiocarbon Dioxide (^{14}CO_{2}) at and Below Ambient Levels

    NASA Astrophysics Data System (ADS)

    Long, David A.; Fleisher, Adam J.; Liu, Qingnan; Hodges, Joseph T.

    2017-06-01

    Due to their age, fossil fuels and their byproducts are almost entirely depleted in radiocarbon (^{14}C). As a result, measurements of radiocarbon provide a unique tracer for determining the origin of products and emissions. Recent efforts at NIST have applied mid-infrared cavity ring-down spectroscopy to measurements of radiocarbon dioxide to allow for more rapid and less expensive measurements than are possible with traditional techniques such as accelerator mass spectrometry. I will discuss our present measurement detection limits and precision as well as discuss limiting noise sources and plans to further improve the instrument's stability and reproducibility.

  13. Global Perspectives on Cancer Health Disparities: Impact, Utility, and Implications for Cancer Nursing

    PubMed Central

    So, Winnie K. W.; Chan, Raymond Javan; Truant, Tracy; Trevatt, Paul; Bialous, Stella Aguinaga; Barton-Burke, Margaret

    2016-01-01

    This paper examines cancer health disparities and contributing factors at national, regional, and international levels. The authors all live in different countries and regions with different health-care systems and practices. Despite the shared cancer nursing perspective, each country or global region approaches cancer disparities differently. With globalization the world is becoming smaller, and in turn becoming interconnected and interdependent. This article focuses on cancer health disparities and global cancer nursing, exemplifying these concepts about the impact and implications of person-centered care. PMID:28083548

  14. Holocene radiocarbon-dated sites in northeastern Siberia: issues of temporal frequency, reservoir age, and human-nature interaction.

    PubMed

    Kuzmin, Yaroslav V

    2010-01-01

    The existing corpus of data on radiocarbon dates for Holocene sites in Northeastern Siberia was used as proxy to reconstruct the chronology of human occupation of the region. The problem of reservoir age correction in the Bering Sea region complicated this task and this issue needs to be solved in order to obtain more reliable age determinations for coastal archaeological sites. Using a chronology built after excluding the questionable dates from the database, the major patterns of human population dynamics and their possible correlation with climatic fluctuations were examined. No direct relationship appears to exist between these two processes. Additional archaeological and paleo environmental work needs to be carried out in this region of the North.

  15. Radiocarbon and stable isotope investigations at the Central Rhineland sites of Gönnersdorf and Andernach-Martinsberg, Germany.

    PubMed

    Stevens, Rhiannon E; O'Connell, Tamsin C; Hedges, Robert E M; Street, Martin

    2009-08-01

    of the two sites not detectable at the level of precision of current radiocarbon dating techniques. No spatial trends in the faunal isotope signatures were observed within each site. In the case of samples with both radiocarbon and isotope data, no chronological pattern was observed for the isotope results. The Magdalenian faunal isotope signatures at the two sites resembled each other, suggesting comparable climatic and environmental conditions. The faunal delta(13)C signatures at Gönnersdorf and Andernach-Martinsberg were similar to those at contemporary European sites. While the faunal delta(15)N values were similar to those at contemporary sites in Germany, the UK, and Belgium, they were lower than those from the South of France. This difference in delta(15)N values is thought to relate to regional differences in the timing of changes in soil and plant nitrogen cycling in response to ameliorating climatic conditions.

  16. Eliminating Disparities in School Discipline

    ERIC Educational Resources Information Center

    Nishioka, Vicki

    2013-01-01

    Disparities in suspension rates for White, Black, Hispanic, and American Indian students are more often a result of inequitable disciplinary actions than differences in behavior. Exclusionary discipline undermines students' academic achievement by weakening their connection with school and removing them from the classroom. Students who experience…

  17. Global ovarian cancer health disparities

    PubMed Central

    Chornokur, Ganna; Amankwah, Ernest K.; Schildkraut, Joellen M.; Phelan, Catherine M.

    2013-01-01

    Objective The objective of this article is to broadly review the scientific literature and summarize the most up-to-date findings on ovarian cancer health disparities worldwide and in the United States (U.S.). Methods The present literature on disparities in ovarian cancer was reviewed. Original research and relevant review articles were included. Results Ovarian cancer health disparities exist worldwide and in the U.S. Ovarian cancer disproportionately affect African American women at all stages of the disease, from presentation through treatment, and ultimately increased mortality and decreased survival, compared to non-Hispanic White women. Increased mortality is likely to be explained by unequal access to care and non-standard treatment regimens frequently administered to African American women, but may also be attributed to genetic susceptibility, acquired co-morbid conditions and increased frequency of modifiable risk factors, albeit to substantially lesser extent. Unequal access to care is, in turn, largely a consequence of lower socioeconomic status and lack of private health insurance coverage among the African American population. Conclusions Our findings suggest the need for policy changes aimed at facilitating equal access to quality medical care. At the same time, further research is necessary to fully resolve racial disparities in ovarian cancer. PMID:23266352

  18. Eliminating Disparities in School Discipline

    ERIC Educational Resources Information Center

    Nishioka, Vicki

    2013-01-01

    Disparities in suspension rates for White, Black, Hispanic, and American Indian students are more often a result of inequitable disciplinary actions than differences in behavior. Exclusionary discipline undermines students' academic achievement by weakening their connection with school and removing them from the classroom. Students who experience…

  19. Toward Explaining Mental Health Disparities

    ERIC Educational Resources Information Center

    Aneshensel, Carol S.

    2009-01-01

    Mental health disparities refer to the disproportionate amount of psychopathology found among persons of disadvantageous social standing, such as persons of low socioeconomic status (SES). Although social and self selection cannot entirely be ruled out as explanations for these differences, the accumulation of evidence supports a social causation…

  20. Late Quaternary sedimentological and climate changes at Lake Bosumtwi Ghana: new constraints from laminae analysis and radiocarbon age modeling

    USGS Publications Warehouse

    Shanahan, Timothy M.; Beck, J. Warren; Overpeck, Jonathan T.; McKay, Nicholas P.; Pigati, Jeffrey S.; Peck, John A.; Scholz, Christopher A.; Heil, Clifford W.; King, John W.

    2012-01-01

    The Lake Bosumtwi sediment record represents one of the longest and highest-resolution terrestrial records of paleoclimate change available from sub-Saharan Africa. Here we report a new sediment age model framework for the last ~ 45 cal kyr of sedimentation using a combination of high-resolution radiocarbon dating, Bayesian age-depth modeling and lamination counting. Our results highlight the practical limits of these methods for reducing age model uncertainties and suggest that even with very high sampling densities, radiocarbon uncertainties of at least a few hundred years are unavoidable. Age model uncertainties are smallest during the Holocene (205 yr) and the glacial (360 yr) but are large at the base of the record (1660 yr), due to a combination of decreasing sample density, larger calibration uncertainties and increases in radiocarbon age scatter. For portions of the chronology older than ~ 35 cal kyr, additional considerations, such as the use of a low-blank graphitization system and more rigorous sample pretreatment were necessary to generate a reliable age depth model because of the incorporation of small amounts of younger carbon. A comparison of radiocarbon age model results and lamination counts over the time interval ~ 15–30 cal kyr agree with an overall discrepancy of ~ 10% and display similar changes in sedimentation rate, supporting the annual nature of sediment laminations in the early part of the record. Changes in sedimentation rates reconstructed from the age-depth model indicate that intervals of enhanced sediment delivery occurred at 16–19, 24 and 29–31 cal kyr, broadly synchronous with reconstructed drought episodes elsewhere in northern West Africa and potentially, with changes in Atlantic meridional heat transport during North Atlantic Heinrich events. These data suggest that millennial-scale drought events in the West African monsoon region were latitudinally extensive, reaching within several hundred kilometers of the Guinea coast

  1. Local Surface Structure From Disparity Measurements

    NASA Astrophysics Data System (ADS)

    Jenkin, Michael R. M.; Jepson, Allan D.; Tsotsos, John K.

    1988-02-01

    Current theories of stereopsis involve three distinct stages: First, the two images of a stereo pair are processed separately to extract monocular features. One common choice of feature is the presence of a zero-crossing in a bandpassed versions of the image. Second, the monocular features in one image are matched with corresponding features found in the other image. In practice this second stage cannot be expected to produce only the correct matches, and a third stage must be considered in order to remove the incorrect matches ("false targets"). There are therefore three main issues the design of such a traditional algorithm for stereopsis, namely i) the choice of image features; the choice of matching criteria; and iii) the way false targets are avoided or eliminated. In this paper we introduce a different approach. We propose that symbolic features should not be extracted from the monocular images in the first stage of processing. Rather we examine a technique for measuring the local phase difference between the two images. We show how local phase difference in a bandpassed version of the image can be interpreted as disparity. This essentially combines the first two stages of the traditional approach. These disparity measurements may contain "false targets" which must be eliminated. Building upon the results of these disparty detectors, we show that a simple surface model based on object cohesiveness and local surface planarity across a range of spatial-frequency tuned channels can be used to reduce false matches. The resulting local planar surface support can be used to segment the image into planar regions in depth. Due to the independent nature of both the disparity detection and local planar support mechanism, this method is capable of dealing with both opaque and transparent stimuli.

  2. Wealth Inequality: Ethnic Disparities in Israeli Society

    ERIC Educational Resources Information Center

    Semyonov, Moshe; Lewin-Epstein, Noah

    2011-01-01

    This research examines wealth distribution across ethnic groups in Israel and evaluates the role of labor market rewards and intergenerational transfers in producing ethnic disparities. Israel SHARE data from 2005-2006 are used in the analyses. The findings reveal considerable ethnic disparities in wealth. Wealth disparities are most pronounced…

  3. 29 CFR 1607.11 - Disparate treatment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Disparate treatment. 1607.11 Section 1607.11 Labor... EMPLOYEE SELECTION PROCEDURES (1978) General Principles § 1607.11 Disparate treatment. The principles of disparate or unequal treatment must be distinguished from the concepts of validation. A selection...

  4. 29 CFR 1607.11 - Disparate treatment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 4 2014-07-01 2014-07-01 false Disparate treatment. 1607.11 Section 1607.11 Labor... EMPLOYEE SELECTION PROCEDURES (1978) General Principles § 1607.11 Disparate treatment. The principles of disparate or unequal treatment must be distinguished from the concepts of validation. A selection procedure...

  5. 29 CFR 1607.11 - Disparate treatment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 4 2011-07-01 2011-07-01 false Disparate treatment. 1607.11 Section 1607.11 Labor... EMPLOYEE SELECTION PROCEDURES (1978) General Principles § 1607.11 Disparate treatment. The principles of disparate or unequal treatment must be distinguished from the concepts of validation. A selection procedure...

  6. 29 CFR 1607.11 - Disparate treatment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 4 2013-07-01 2013-07-01 false Disparate treatment. 1607.11 Section 1607.11 Labor... EMPLOYEE SELECTION PROCEDURES (1978) General Principles § 1607.11 Disparate treatment. The principles of disparate or unequal treatment must be distinguished from the concepts of validation. A selection procedure...

  7. Wealth Inequality: Ethnic Disparities in Israeli Society

    ERIC Educational Resources Information Center

    Semyonov, Moshe; Lewin-Epstein, Noah

    2011-01-01

    This research examines wealth distribution across ethnic groups in Israel and evaluates the role of labor market rewards and intergenerational transfers in producing ethnic disparities. Israel SHARE data from 2005-2006 are used in the analyses. The findings reveal considerable ethnic disparities in wealth. Wealth disparities are most pronounced…

  8. The National Health Plan Collaborative to Reduce Disparities and Improve Quality.

    PubMed

    Lurie, Nicole; Fremont, Allen; Somers, Stephen A; Coltin, Kathryn; Gelzer, Andrea; Johnson, Rhonda; Rawlins, Wayne; Ting, Grace; Wong, Winston; Zimmerman, Donna

    2008-05-01

    Despite numerous reports and initiatives, progress in reducing racial/ethnic disparities in health care has been slow. The National Health Plan Collaborative (NHPC), a novel public-private partnership between nine health plans covering approximately 95 million lives, leading learning and research organizations, the Agency for Healthcare Research and Quality, and the Robert Wood Johnson Foundation, was established in December 2004 to address these disparities. The health plans were able to overcame initial challenges in obtaining information on race/ethnicity of their enrollees and examined their diabetes performance measure to assess disparities in care. By February 2006, the initial nine plans that had joined the NHPC progressed from focusing solely on data collection and management issues and were engaged in outreach activities to members, providers, or community or had completed capacity development for disparities work. Five plans had implemented one or more pilot interventions. Plans also addressed unanticipated challenges, such as sorting through large amounts of data to target disparities. Because many of the plans are complex national entities with varying regional and departmental structures, simply achieving coordination of disparities activities across the organization has been a major challenge and, in many cases, a major breakthrough. The NHPC represents a model of shared learning and innovation through which health plans are tackling racial/ethnic disparities. Now that most of the plans have some data on their enrollees with diabetes and have begun targeting disparities, they want to capitalize on their collective industry strength to influence policy on issues related to disparities.

  9. Decomposing racial/ethnic disparities in influenza vaccination among the elderly.

    PubMed

    Yoo, Byung-Kwang; Hasebe, Takuya; Szilagyi, Peter G

    2015-06-12

    While persistent racial/ethnic disparities in influenza vaccination have been reported among the elderly, characteristics contributing to disparities are poorly understood. This study aimed to assess characteristics associated with racial/ethnic disparities in influenza vaccination using a nonlinear Oaxaca-Blinder decomposition method. We performed cross-sectional multivariable logistic regression analyses for which the dependent variable was self-reported receipt of influenza vaccine during the 2010-2011 season among community dwelling non-Hispanic African-American (AA), non-Hispanic White (W), English-speaking Hispanic (EH) and Spanish-speaking Hispanic (SH) elderly, enrolled in the 2011 Medicare Current Beneficiary Survey (MCBS) (un-weighted/weighted N=6,095/19.2 million). Using the nonlinear Oaxaca-Blinder decomposition method, we assessed the relative contribution of seventeen covariates - including socio-demographic characteristics, health status, insurance, access, preference regarding healthcare, and geographic regions - to disparities in influenza vaccination. Unadjusted racial/ethnic disparities in influenza vaccination were 14.1 percentage points (pp) (W-AA disparity, p<0.001), 25.7 pp (W-SH disparity, p<0.001) and 0.6 pp (W-EH disparity, p>.8). The Oaxaca-Blinder decomposition method estimated that the unadjusted W-AA and W-SH disparities in vaccination could be reduced by only 45% even if AA and SH groups become equivalent to Whites in all covariates in multivariable regression models. The remaining 55% of disparities were attributed to (a) racial/ethnic differences in the estimated coefficients (e.g., odds ratios) in the regression models and (b) characteristics not included in the regression models. Our analysis found that only about 45% of racial/ethnic disparities in influenza vaccination among the elderly could be reduced by equalizing recognized characteristics among racial/ethnic groups. Future studies are needed to identify additional

  10. Decomposing Racial/Ethnic Disparities in Influenza Vaccination among the Elderly

    PubMed Central

    Yoo, Byung-Kwang; Hasebe, Takuya; Szilagyi, Peter G.

    2015-01-01

    While persistent racial/ethnic disparities in influenza vaccination have been reported among the elderly, characteristics contributing to disparities are poorly understood. This study aimed to assess characteristics associated with racial/ethnic disparities in influenza vaccination using a nonlinear Oaxaca-Blinder decomposition method. We performed cross-sectional multivariable logistic regression analyses for which the dependent variable was self-reported receipt of influenza vaccine during the 2010–2011 season among community dwelling non-Hispanic African-American (AA), non-Hispanic White (W), English-speaking Hispanic (EH) and Spanish-speaking Hispanic (SH) elderly, enrolled in the 2011 Medicare Current Beneficiary Survey (MCBS) (un-weighted/weighted N= 6,095/19.2million). Using the nonlinear Oaxaca-Blinder decomposition method, we assessed the relative contribution of seventeen covariates—including socio-demographic characteristics, health status, insurance, access, preference regarding healthcare, and geographic regions —to disparities in influenza vaccination. Unadjusted racial/ethnic disparities in influenza vaccination were 14.1 percentage points (pp) (W-AA disparity, p<.001), 25.7 pp (W-SH disparity, p<.001) and 0.6 pp (W-EH disparity, p>.8). The Oaxaca-Blinder decomposition method estimated that the unadjusted W-AA and W-SH disparities in vaccination could be reduced by only 45% even if AA and SH groups become equivalent to Whites in all covariates in multivariable regression models. The remaining 55% of disparities were attributed to (a) racial/ethnic differences in the estimated coefficients (e.g., odds ratios) in the regression models and (b) characteristics not included in the regression models. Our analysis found that only about 45% of racial/ethnic disparities in influenza vaccination among the elderly could be reduced by equalizing recognized characteristics among racial/ethnic groups. Future studies are needed to identify additional

  11. Solar activity around AD 775 from aurorae and radiocarbon

    NASA Astrophysics Data System (ADS)

    Neuhäuser, R.; Neuhäuser, D. L.

    2015-04-01

    A large variation in 14C around AD 775 has been considered to be caused by one or more solar super-flares within one year. We critically review all known aurora reports from Europe as well as the Near, Middle, and Far East from AD 731 to 825 and find 39 likely true aurorae plus four more potential aurorae and 24 other reports about halos, meteors, thunderstorms etc., which were previously misinterpreted as aurorae or misdated; we assign probabilities for all events according to five aurora criteria. We find very likely true aurorae in AD 743, 745, 762, 765, 772, 773, 793, 796, 807, and 817. There were two aurorae in the early 770s observed near Amida (now Diyarbak\\i r in Turkey near the Turkish-Syrian border), which were not only red, but also green-yellow - being at a relatively low geomagnetic latitude, they indicate a relatively strong solar storm. However, it cannot be argued that those aurorae (geomagnetic latitude 43 to 50°, considering five different reconstructions of the geomagnetic pole) could be connected to one or more solar super-flares causing the 14C increase around AD 775: There are several reports about low- to mid-latitude aurorae at 32 to 44° geomagnetic latitude in China and Iraq; some of them were likely observed (quasi-)simultaneously in two of three areas (Europe, Byzantium/Arabia, East Asia), one lasted several nights, and some indicate a particularly strong geomagnetic storm (red colour and dynamics), namely in AD 745, 762, 793, 807, and 817 - always without 14C peaks. We use 39 likely true aurorae as well as historic reports about sunspots together with the radiocarbon content from tree rings to reconstruct the solar activity: From AD {˜ 733} to {˜ 823}, we see at least nine Schwabe cycles; instead of one of those cycles, there could be two short, weak cycles - reflecting the rapid increase to a high 14C level since AD 775, which lies at the end of a strong cycle. In order to show the end of the dearth of naked-eye sunspots, we

  12. Age validation of quillback rockfish (Sebastes maliger) using bomb radiocarbon

    SciTech Connect

    Kerr, L A; Andrews, A H; Munk, K; Coale, K H; Frantz, B R; Cailliet, G M; Brown, T A

    2005-01-05

    Rockfishes (Sebastes spp.) support one of the most economically important fisheries of the Pacific Northwest and it is essential for sustainable management that age estimation procedures be validated for these species. Atmospheric testing of thermonuclear devices during the 1950s and 1960s created a global radiocarbon ({sup 14}C) signal in the ocean environment that scientists have identified as a useful tracer and chronological marker in natural systems. In this study, we first demonstrated that fewer samples are necessary for age validation using the bomb-generated {sup 14}C signal by emphasizing the utility of the time-specific marker created by the initial rise of bomb-{sup 14}C. Second, the bomb-generated {sup 14}C signal retained in fish otoliths was used to validate the age and age estimation methodology of the quillback rockfish (Sebastes maliger) in the waters of southeast Alaska. Radiocarbon values from the first year's growth of quillback rockfish otoliths were plotted against estimated birth year producing a {sup 14}C time series spanning 1950 to 1985. The initial rise of bomb-{sup 14}C from pre-bomb levels ({approx} -90 {per_thousand}) occurred in 1959 {+-} 1 year and {sup 14}C levels rose relatively rapidly to peak {Delta}{sup 14}C values in 1967 (+105.4 {per_thousand}), with a subsequent declining trend through the end of the record in 1985 (+15.4 {per_thousand}). The agreement between the year of initial rise of {sup 14}C levels from the quillback rockfish record and the chronometer determined for the waters of southeast Alaska from yelloweye rockfish (S. ruberrimus) otoliths validated the ageing methodology for the quillback rockfish. The concordance of the entire quillback rockfish {sup 14}C record with the yelloweye rockfish time series demonstrated the effectiveness of this age validation technique, confirmed the longevity of the quillback rockfish up to a minimum of 43 years, and strongly supports higher age estimates of up to 90 years.

  13. BIOGENIC CONTRIBUTION TO PM-2.5 AMBIENT AEROSOL FROM RADIOCARBON MEASUREMENTS

    EPA Science Inventory

    Knowledge of the relative contributions of biogenic versus anthropogenic sources to ambient aerosol is of great interest in the formulation of strategies to achieve nationally mandated air quality standards. Radiocarbon (Carbon-14) measurements provide a means to quantify the ...

  14. BIOGENIC CONTRIBUTION TO PM-2.5 AMBIENT AEROSOL FROM RADIOCARBON MEASUREMENTS

    EPA Science Inventory

    Knowledge of the relative contributions of biogenic versus anthropogenic sources to ambient aerosol is of great interest in the formulation of strategies to achieve nationally mandated air quality standards. Radiocarbon (Carbon-14) measurements provide a means to quantify the ...

  15. Geographic disparity in premature mortality in Ontario, 1992–1996

    PubMed Central

    Altmayer, Chris A; Hutchison, Brian G; Torrance-Rynard, Vicki L; Hurley, Jeremiah; Birch, Stephen; Eyles, John D

    2003-01-01

    Background Standardized mortality ratios are used to identify geographic areas with higher or lower mortality than expected. This article examines geographic disparity in premature mortality in Ontario, Canada, at three geographic levels of population and considers factors that may underlie variations in premature mortality across geographic areas. All-cause, sex and disease chapter specific premature mortality were analyzed at the regional, district and public health unit level to determine the extent of geographic variation. Standardized mortality ratios for persons aged 0–74 years were calculated to identify geographic areas with significantly higher or lower premature mortality than expected, using Ontario death rates as the basis for the calculation of expected deaths in the local population. Data are also presented from the household component of the 1996/97 National Population Health Survey and from the 1996 Statistics Canada Census. Results Results showed approximately 20% higher than expected all-cause premature mortality for males and females in the North region. However, disparity in all-cause premature mortality in Ontario was most pronounced at the public health unit level, ranging from 20% lower than expected to 30% higher than expected. Premature mortality disparities were largely influenced by neoplasms, circulatory diseases, injuries and poisoning, respiratory diseases and digestive diseases, which accounted for more than 80% of all premature deaths. Premature mortality disparities were also more pronounced for disease chapter specific mortality. Conclusion Geographic disparities in premature mortality are clearly greater at the small area level. Geographic disparities in premature mortality undoubtedly reflect the underlying distribution of population health determinants such as health related behaviours, social, economic and environmental influences. PMID:14561226

  16. Radiocarbon-depleted CO2 evidence for fuel biodegradation at the Naval Air Station North Island (USA) fuel farm site.

    PubMed

    Boyd, Thomas J; Pound, Michael J; Lohr, Daniel; Coffin, Richard B

    2013-05-01

    Dissolved CO(2) radiocarbon and stable carbon isotope ratios were measured in groundwater from a fuel contaminated site at the North Island Naval Air Station in San Diego, CA (USA). A background groundwater sampling well and 16 wells in the underground fuel contamination zone were evaluated. For each sample, a two end-member isotopic mixing model was used to determine the fraction of CO(2) derived from fossil fuel. The CO(2) fraction from fossil sources ranged from 8 to 93% at the fuel contaminated site, while stable carbon isotope values ranged from -14 to +5‰VPDB. Wells associated with highest historical and contemporary fuel contamination showed the highest fraction of CO(2) derived from petroleum (fossil) sources. Stable carbon isotope ratios indicated sub-regions on-site with recycled CO(2) (δ(13)CO(2) as high as +5‰VPDB) - most likely resulting from methanogenesis. Ancillary measurements (pH and cations) were used to determine that no fossil CaCO(3), for instance limestone, biased the analytical conclusions. Radiocarbon analysis is verified as a viable and definitive technique for confirming fossil hydrocarbon conversion to CO(2) (complete oxidation) at hydrocarbon-contaminated groundwater sites. The technique should also be very useful for assessing the efficacy of engineered remediation efforts and by using CO(2) production rates, contaminant mass conversion over time and per unit volume.

  17. Characterizing the export of fossil carbon from permafrost soils of Spitsbergen using compound-specific radiocarbon dating

    NASA Astrophysics Data System (ADS)

    Mollenhauer, G.; Kusch, S.; Rethemeyer, J.

    2012-04-01

    Permafrost soils in the circumpolar Arctic regions contain vast amounts of carbon stored as organic matter, which could potentially be mobilized during the climate warming expected to be particularly severe in these regions. Deeper thawing of permafrost soils may result in degradation and erosion of previously freeze-locked organic matter, followed by transport to the ocean and respiration to CO2. We studied a small catchment area covered by permafrost soils on the island of Spitsbergen at approximately 78°N, Svalbard archipelago. Total organic carbon (TOC) in a soil profile of the annually thawed active layer exhibits increasing radiocarbon ages with depth of 5800 conventional radiocarbon years (14C yrs BP) in 0 to 30 cm depth to 26000 14C yrs BP at 60-85 cm. However, in this region known for its occurrence of carboniferous and tertiary coals, these ages are likely biased by variable relative contributions of fossil coal particles. Compound-specific radiocarbon ages of short-chain (C16) and long-chain (C26 and C28) fatty acids, which are derived mainly from bacteria and recent tundra vegetation, respectively, aree substantially younger than TOC, but still reach values between 2280 14C yrs BP for C16 in the uppermost 0-30 cm and 8350 14C yrs BP for C26 fatty acids in the 30-60 cm soil depth interval. Obviously, several different carbon pools contribute to TOC in the soil profile, and carbon turnover is slow. Radiocarbon dating of long-chain (C26-C28) fatty acids recovered from core-top sediments of the Bayelva river draining the catchment and from shallow water fjord sediments directly off the river mouth yields 14C ages of 10800 and 7900 yrs BP, respectively. As the C16 fatty acids in marine sediments are primarily attributed to marine phytoplankton, its modern in the marine sediment age clearly identifies it as a recent sediment, in which old terrestrial plant material is deposited. Apparently, this terrigenous material is buried near shore, as 14C ages of long

  18. Application of compound-specific radiocarbon dating for Antarctic margin sediments

    NASA Astrophysics Data System (ADS)

    Ohkouchi, N.; Koizumi, M.; Anderson, J. B.; Eglinton, T. I.; Miura, H.; Yokoyama, Y.

    2008-12-01

    Radiocarbon dating has been extensively applied for the development of chronologies of Antarctic margin sediments deposited during the late Quaternary. However, the problems are 1) the DIC reservoir age in the surface mixed layer is much older than that of the other oceans, 2) Antarctic margin sediments generally lack calcareous foraminifera conventionally used for radiocarbon dating and as stratigraphic tool, and 3) the sediments are subjected to significant "contamination" of relict organic matter eroded from the Antarctic continent, leading to substantially older radiocarbon ages of bulk sedimentary organic matter. Ohkouchi et al. (2003) first applied compound-specific radiocarbon dating to the surface sediments collected from Ross Sea, Antarctica for resolving the problem. They reported that the radiocarbon ages of solvent-extractable, short-chain (C14, C16, and C18) fatty acids are consistent with the modern DIC reservoir age (Pre-bomb: 14C -150, Post-bomb: 14C -100). Furthermore, the radiocarbon ages of these fatty acids at five down-core intervals progressively increase with the core depth. These results clearly show a utility of the compound- specific radiocarbon dating for developing sediment chronologies in Antarctic margin sediments. We also determined radiocarbon ages of the fatty acids from a core recovered in the NW Ross Sea to reconstruct sediment chronologies. Furthermore, we determined hydrogen isotopic compositions of sedimentary biomarkers in the core. Around 6.8, 5.7, 4.1, 2.5, and 1.5 kyr ago, the reconstructed D values of paleo- seawater were -200 or lower, suggesting a large amount of meltwater influx to the Ross Sea. Currently, we are applying the method to more sediment samples collected from wider area of Ross Sea to investigate the timing and pattern of retreat of West Antarctic Ice Sheet in the Holocene. I will present the up-dated results in my talk.

  19. Improving estimates of surface water radiocarbon reservoir ages in the northeastern Atlantic Ocean.

    NASA Astrophysics Data System (ADS)

    Greenop, Rosanna; Burke, Andrea; Rae, James; Austin, William; Reimer, Paula; Blaauw, Maarten; Crocker, Anya; Chalk, Thomas; Barker, Stephen; Knutz, Paul; Hall, Ian

    2016-04-01

    Radiocarbon measurements from foraminifera in marine sediment cores are widely used to constrain age models and the timing of paleoceanographic events, as well as past changes in ocean circulation and carbon cycling. However, the use of radiocarbon for both dating and palaeoceanographic applications is limited in sediment cores by a lack of knowledge about the surface ocean radiocarbon reservoir age and how it varies in both space and time. Typically, to convert a planktic radiocarbon age into a calendar age, an assumed constant reservoir age is applied. However, there is mounting evidence to suggest that this assumption of constant reservoir age through time is an oversimplification, particularly for the high latitude oceans during the cold climates of the last glacial and deglacial periods. Here we present new high-resolution radiocarbon records together with tephra tie points and 230-thorium (230Th) constrained sedimentation rates to improve estimates of radiocarbon reservoir age in the Northeast Atlantic Ocean. In addition we will explore the impact of the new reservoir ages for both the age models of the cores studied, as well as the palaeoceanographic implications of these reservoir age changes during intervals of rapid climate change over the past 40,000 years.

  20. Radiocarbon dates on bones of extinct birds from Hawaii

    SciTech Connect

    James, H.F.; Stafford, T.W. Jr.; Steadman, D.W.; Olson, S.L.; Martin, P.S.; Jull, A.J.; McCoy, P.C.

    1987-04-01

    Bones from a stratified sedimentary deposit in the Puu Naio Cave site on Maui, Hawaiian Islands, reveal the late Holocene extinction of 19 species of birds. The age of the sediment and associated fauna was determined by direct radiocarbon dating (tandem particle accelerator-mass spectrometer; TAMS) of amino acids extracted from bones weighing as little as 450 mg. The /sup 14/C dates indicate that sediment has been accumulating in the lava tube for at least the last 7750 years, a suitable time frame for testing the hypothesis that Holocene extinction on islands began after human colonization. Despite growing evidence that a worldwide wave of extinctions coincided with human colonization of oceanic islands, little radiometric data have been available to date the extinction of most small fossil vertebrates on islands. The TAMS technique of dating purified collagen from the bones of small vertebrates could lead to vastly improved chronologies of extinction for oceanic islands where catastrophic mid- to late-Holocene extinction is expected or known to have occurred. Chronologies derived from nonarcheological sites that show continuous sedimentation, such as the Puu Naio Cave deposit, may also yield key evidence on the timing of earliest human settlement of Oceania.

  1. Mortar radiocarbon dating: preliminary accuracy evaluation of a novel methodology.

    PubMed

    Marzaioli, Fabio; Lubritto, Carmine; Nonni, Sara; Passariello, Isabella; Capano, Manuela; Terrasi, Filippo

    2011-03-15

    Mortars represent a class of building and art materials that are widespread at archeological sites from the Neolithic period on. After about 50 years of experimentation, the possibility to evaluate their absolute chronology by means of radiocarbon ((14)C) remains still uncertain. With the use of a simplified mortar production process in the laboratory environment, this study shows the overall feasibility of a novel physical pretreatment for the isolation of the atmospheric (14)CO(2) (i.e., binder) signal absorbed by the mortars during their setting. This methodology is based on the assumption that an ultrasonic attack in liquid phase isolates a suspension of binder carbonates from bulk mortars. Isotopic ((13)C and (14)C), % C, X-ray diffractometry (XRD), and scanning electron microscopy (SEM) analyses were performed to characterize the proposed methodology. The applied protocol allows suppression of the fossil carbon (C) contamination originating from the incomplete burning of the limestone during the quick lime production, providing unbiased dating for "laboratory" mortars produced operating at historically adopted burning temperatures.

  2. The Remarkable Metrological History of Radiocarbon Dating [II].

    PubMed

    Currie, Lloyd A

    2004-01-01

    This article traces the metrological history of radiocarbon, from the initial breakthrough devised by Libby, to minor (evolutionary) and major (revolutionary) advances that have brought (14)C measurement from a crude, bulk [8 g carbon] dating tool, to a refined probe for dating tiny amounts of precious artifacts, and for "molecular dating" at the 10 µg to 100 µg level. The metrological advances led to opportunities and surprises, such as the non-monotonic dendrochronological calibration curve and the "bomb effect," that gave rise to new multidisciplinary areas of application, ranging from archaeology and anthropology to cosmic ray physics to oceanography to apportionment of anthropogenic pollutants to the reconstruction of environmental history. Beyond the specific topic of natural (14)C, it is hoped that this account may serve as a metaphor for young scientists, illustrating that just when a scientific discipline may appear to be approaching maturity, unanticipated metrological advances in their own chosen fields, and unanticipated anthropogenic or natural chemical events in the environment, can spawn new areas of research having exciting theoretical and practical implications.

  3. Radiocarbon-derived sedimentation rates in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Santschi, Peter H.; Rowe, Gilbert T.

    2008-12-01

    Sedimentation rates were determined for the northern Gulf of Mexico margin sediments at water depths ranging from 770 to 3560 m, using radiocarbon determinations of organic matter. Resulting sedimentation rates ranged from 3 to 15 cm/kyr, decreasing with increasing water depth. These rates agree with long-term sedimentation rates estimated previously using stratigraphic methods, and with estimates of sediment delivery rates by the Mississippi River to the northern Gulf of Mexico, but are generally higher by 1-2 orders of magnitude than those estimated by 210Pb xs methods. Near-surface slope sediments from 2737 m water depth in the Mississippi River fan were much older than the rest. They had minimum 14C ages of 16-27 kyr and δ13C values ranging from -24‰ to -26.5‰, indicating a terrestrial origin of organic matter. The sediments from this site were thus likely deposited by episodic mass wasting of slope sediment through the canyon, delineating the previously suggested main pathway of sediment and clay movement to abyssal Gulf sediments.

  4. The Remarkable Metrological History of Radiocarbon Dating [II

    PubMed Central

    Currie, Lloyd A.

    2004-01-01

    This article traces the metrological history of radiocarbon, from the initial breakthrough devised by Libby, to minor (evolutionary) and major (revolutionary) advances that have brought 14C measurement from a crude, bulk [8 g carbon] dating tool, to a refined probe for dating tiny amounts of precious artifacts, and for “molecular dating” at the 10 µg to 100 µg level. The metrological advances led to opportunities and surprises, such as the non-monotonic dendrochronological calibration curve and the “bomb effect,” that gave rise to new multidisciplinary areas of application, ranging from archaeology and anthropology to cosmic ray physics to oceanography to apportionment of anthropogenic pollutants to the reconstruction of environmental history. Beyond the specific topic of natural 14C, it is hoped that this account may serve as a metaphor for young scientists, illustrating that just when a scientific discipline may appear to be approaching maturity, unanticipated metrological advances in their own chosen fields, and unanticipated anthropogenic or natural chemical events in the environment, can spawn new areas of research having exciting theoretical and practical implications. PMID:27366605

  5. Radiocarbon Releases from the 2011 Fukushima Nuclear Accident

    NASA Astrophysics Data System (ADS)

    Xu, Sheng; Cook, Gordon T.; Cresswell, Alan J.; Dunbar, Elaine; Freeman, Stewart P. H. T.; Hou, Xiaolin; Jacobsson, Piotr; Kinch, Helen R.; Naysmith, Philip; Sanderson, David C. W.; Tripney, Brian G.

    2016-11-01

    Radiocarbon activities were measured in annual tree rings for the years 2009 to 2015 from Japanese cedar trees (Cryptomeria japonica) collected at six sites ranging from 2.5-38 km northwest and north of the Fukushima Dai-ichi nuclear power plant. The 14C specific activity varied from 280.4 Bq kg-1 C in 2010 to 226.0 Bq kg-1 C in 2015. The elevated 14C activities in the 2009 and 2010 rings confirmed 14C discharges during routine reactor operations, whereas those activities that were indistinguishable from background in 2012-2015 coincided with the permanent shutdown of the reactors after the accident in 2011. High-resolution 14C analysis of the 2011 ring indicated 14C releases during the Fukushima accident. The resulted 14C activity decreased with increasing distance from the plant. The maximum 14C activity released during the period of the accident was measured 42.4 Bq kg-1 C above the natural ambient 14C background. Our findings indicate that, unlike other Fukushima-derived radionuclides, the 14C released during the accident is indistinguishable from ambient background beyond the local environment (~30 km from the plant). Furthermore, the resulting dose to the local population from the excess 14C activities is negligible compared to the dose from natural/nuclear weapons sources.

  6. Single amino acid radiocarbon dating of Upper Paleolithic modern humans

    PubMed Central

    Marom, Anat; McCullagh, James S. O.; Higham, Thomas F. G.; Sinitsyn, Andrey A.; Hedges, Robert E. M.

    2012-01-01

    Archaeological bones are usually dated by radiocarbon measurement of extracted collagen. However, low collagen content, contamination from the burial environment, or museum conservation work, such as addition of glues, preservatives, and fumigants to “protect” archaeological materials, have previously led to inaccurate dates. These inaccuracies in turn frustrate the development of archaeological chronologies and, in the Paleolithic, blur the dating of such key events as the dispersal of anatomically modern humans. Here we describe a method to date hydroxyproline found in collagen (∼10% of collagen carbon) as a bone-specific biomarker that removes impurities, thereby improving dating accuracy and confidence. This method is applied to two important sites in Russia and allows us to report the earliest direct ages for the presence of anatomically modern humans on the Russian Plain. These dates contribute considerably to our understanding of the emergence of the Mid-Upper Paleolithic and the complex suite of burial behaviors that begin to appear during this period. PMID:22517758

  7. Radiocarbon dates on bones of extinct birds from Hawaii.

    PubMed Central

    James, H F; Stafford, T W; Steadman, D W; Olson, S L; Martin, P S; Jull, A J; McCoy, P C

    1987-01-01

    Bones from a stratified sedimentary deposit in the Puu Naio Cave site on Maui, Hawaiian Islands, reveal the late Holocene extinction of 19 species of birds. The age of the sediment and associated fauna was determined by direct radiocarbon dating (tandem particle accelerator-mass spectrometer; TAMS) of amino acids extracted from bones weighing as little as 450 mg. The 14C dates indicate that sediment has been accumulating in the lava tube for at least the last 7750 years, a suitable time frame for testing the hypothesis that Holocene extinction on islands began after human colonization. Despite growing evidence that a worldwide wave of extinctions coincided with human colonization of oceanic islands, little radiometric data have been available to date the extinction of most small fossil vertebrates on islands. The TAMS technique of dating purified collagen from the bones of small vertebrates could lead to vastly improved chronologies of extinction for oceanic islands where catastrophic mid- to late-Holocene extinction is expected or known to have occurred. Chronologies derived from nonarcheological sites that show continuous sedimentation, such as the Puu Naio Cave deposit, may also yield key evidence on the timing of earliest human settlement of Oceania. Images PMID:3470800

  8. Radiocarbon test of earthquake magnitude at the Cascadia subduction zone

    USGS Publications Warehouse

    Atwater, B.F.; Stuiver, M.; Yamaguchi, D.K.

    1991-01-01

    THE Cascadia subduction zone, which extends along the northern Pacific coast of North America, might produce earthquakes of magnitude 8 or 9 ('great' earthquakes) even though it has not done so during the past 200 years of European observation 1-7. Much of the evidence for past Cascadia earthquakes comes from former meadows and forests that became tidal mudflats owing to abrupt tectonic subsidence in the past 5,000 years2,3,6,7. If due to a great earthquake, such subsidence should have extended along more than 100 km of the coast2. Here we investigate the extent of coastal subsidence that might have been caused by a single earthquake, through high-precision radiocarbon dating of coastal trees that abruptly subsided into the intertidal zone. The ages leave the great-earthquake hypothesis intact by limiting to a few decades the discordance, if any, in the most recent subsidence of two areas 55 km apart along the Washington coast. This subsidence probably occurred about 300 years ago.

  9. Radiocarbon Releases from the 2011 Fukushima Nuclear Accident

    PubMed Central

    Xu, Sheng; Cook, Gordon T.; Cresswell, Alan J.; Dunbar, Elaine; Freeman, Stewart P. H. T.; Hou, Xiaolin; Jacobsson, Piotr; Kinch, Helen R.; Naysmith, Philip; Sanderson, David C. W.; Tripney, Brian G.

    2016-01-01

    Radiocarbon activities were measured in annual tree rings for the years 2009 to 2015 from Japanese cedar trees (Cryptomeria japonica) collected at six sites ranging from 2.5–38 km northwest and north of the Fukushima Dai-ichi nuclear power plant. The 14C specific activity varied from 280.4 Bq kg−1 C in 2010 to 226.0 Bq kg−1 C in 2015. The elevated 14C activities in the 2009 and 2010 rings confirmed 14C discharges during routine reactor operations, whereas those activities that were indistinguishable from background in 2012–2015 coincided with the permanent shutdown of the reactors after the accident in 2011. High-resolution 14C analysis of the 2011 ring indicated 14C releases during the Fukushima accident. The resulted 14C activity decreased with increasing distance from the plant. The maximum 14C activity released during the period of the accident was measured 42.4 Bq kg−1 C above the natural ambient 14C background. Our findings indicate that, unlike other Fukushima-derived radionuclides, the 14C released during the accident is indistinguishable from ambient background beyond the local environment (~30 km from the plant). Furthermore, the resulting dose to the local population from the excess 14C activities is negligible compared to the dose from natural/nuclear weapons sources. PMID:27841312

  10. Anomalous elevated radiocarbon measurements of PM2.5

    NASA Astrophysics Data System (ADS)

    Buchholz, Bruce A.; Fallon, Stewart J.; Zermeño, Paula; Bench, Graham; Schichtel, Bret A.

    2013-01-01

    Two-component models are often used to determine the contributions made by fossil fuel and natural sources of carbon in airborne particulate matter (PM). The models reduce thousands of actual sources to two end members based on isotopic signature. Combustion of fossil fuels produces PM free of carbon-14 (14C). Wood or charcoal smoke, restaurant fryer emissions, and natural emissions from plants produce PM with the contemporary concentration of 14C approximately 1.2 × 10-1214C/C. Such data can be used to estimate the relative contributions of fossil fuels and biogenic aerosols to the total aerosol loading and radiocarbon analysis is becoming a popular source apportionment method. Emissions from incinerators combusting medical or biological wastes containing tracer 14C can skew the 14C/C ratio of PM, however, so critical analysis of sampling sites for possible sources of elevated PM needs to be completed prior to embarking on sampling campaigns. Results are presented for two ambient monitoring sites in different areas of the United States where 14C contamination is apparent. Our experience suggests that such contamination is uncommon but is also not rare (∼10%) for PM sampling sites.

  11. Food Systems and Public Health Disparities

    PubMed Central

    Neff, Roni A.; Palmer, Anne M.; Mckenzie, Shawn E.; Lawrence, Robert S.

    2009-01-01

    The United States has set a national goal to eliminate health disparities. This article emphasizes the importance of food systems in generating and exacerbating health disparities in the United States and suggests avenues for reducing them. It presents a conceptual model showing how broad food system conditions interplay with community food environments—and how these relationships are filtered and refracted through prisms of social disparities to generate and exacerbate health disparities. Interactions with demand factors in the social environment are described. The article also highlights the separate food systems pathway to health disparities via environmental and occupational health effects of agriculture. PMID:23173027

  12. Estimates of upwelling rates in the Arabian Sea and the equatorial Indian Ocean based on bomb radiocarbon.

    PubMed

    Bhushan, R; Dutta, K; Somayajulu, B L K

    2008-10-01

    Radiocarbon measurements were made in the water column of the Arabian Sea and the equatorial Indian Ocean during 1994, 1995 and 1997 to assess the temporal variations in bomb 14C distribution and its inventory in the region with respect to GEOSECS measurements made during 1977-1978. Four GEOSECS stations were reoccupied (three in the Arabian Sea and one in the equatorial Indian Ocean) during this study, with all of them showing increased penetration of bomb 14C along with decrease in its surface water activity. The upwelling rates derived by model simulation of bomb 14C depth profile using the calculated exchange rates ranged from 3 to 9 m a(-1). The western region of the Arabian Sea experiencing high wind-induced upwelling has higher estimated upwelling rates. However, lower upwelling rates obtained for the stations occupied during this study could be due to reduced 14C gradient compared to that during GEOSECS.

  13. The Moral Problem of Health Disparities

    PubMed Central

    2010-01-01

    Health disparities exist along lines of race/ethnicity and socioeconomic class in US society. I argue that we should work to eliminate these health disparities because their existence is a moral wrong that needs to be addressed. Health disparities are morally wrong because they exemplify historical injustices. Contractarian ethics, Kantian ethics, and utilitarian ethics all provide theoretical justification for viewing health disparities as a moral wrong, as do several ethical principles of primary importance in bioethics. The moral consequences of health disparities are also troubling and further support the claim that these disparities are a moral wrong. The Universal Declaration of Human Rights provides additional support that health disparities are a moral wrong, as does an analogy with the generally accepted duty to provide equal access to education. In this article, I also consider and respond to 3 objections to my thesis. PMID:20147677

  14. DIDA - Dynamic Image Disparity Analysis.

    DTIC Science & Technology

    1982-12-31

    Understanding, Dynamic Image Analysis , Disparity Analysis, Optical Flow, Real-Time Processing ___ 20. ABSTRACT (Continue on revere side If necessary aid identify...three aspects of dynamic image analysis must be studied: effectiveness, generality, and efficiency. In addition, efforts must be made to understand the...environment. A better understanding of the need for these Limiting constraints is required. Efficiency is obviously important if dynamic image analysis is

  15. Late Pleistocene Holocene stratigraphy and radiocarbon dating of La Malinche volcano, Central Mexico

    NASA Astrophysics Data System (ADS)

    Castro-Govea, Renato; Siebe, Claus

    2007-04-01

    Previous studies of La Malinche identified and radiocarbon dated several volcanic layers, the youngest of which yielded an age of ca. 7.5 ka. An additional ash fallout layer that crops out at high altitudes was considered the most recent deposit, with an estimated age of 6 ka. In the present work 38 new radiocarbon ages are presented. From these, several date the young ash fallout layer and lie around 3.1 ka. With the aid of these dates a new and comprehensive stratigraphy documenting the Late Pleistocene-Holocene eruptive history of La Malinche is presented. The stratigraphy indicates two main stages of volcanic activity: Pre-Malinche and Malinche. The first undoubtedly comprises the major part of the eruptive history, but its deposits are largely covered by the products of the latter stage, on which this study is focused. The Malinche stage was subdivided into three eruptive periods. Period 1 started with the emplacement of the Huamantla Pumice more than 45 ka ago. This deposit consists of a thick pumice fallout overlain by pyroclastic flow deposits. Subsequently, several episodes of construction and collapse of summit domes occurred. The oldest dome was dated at ca. 45 ka. Period 2 started 21.5 ka ago with the Malinche Pumice I, a widespread pumice fallout covering the entire slopes of the volcano. Pyroclastic flows and lahars related to this eruption were channeled along deep barrancas and reached considerable distances. Deposits produced by partial sector collapse and dated at ca. 20.9 ka, and a pumice-and-ash flow deposit dated at 15.9 ka were also generated during this period. The last period started with the eruption of the Malinche Pumice II, a distinctive fallout deposit overlain by ash flow deposits on the NE slope of the volcano. The age of this pumice layer is estimated between 12 and 9 ka. Formation of block-and-ash flows, lahars and pumice-and-ash flows followed during this period, and peaked in a most intensive episode that was dated at 7.5 ka

  16. Radiocarbon chronology and environment of woolly mammoth ( Mammuthus primigenius Blum.) in northern Asia: results and perspectives

    NASA Astrophysics Data System (ADS)

    Kuzmin, Yaroslav V.; Orlova, Lyobov A.

    2004-12-01

    This paper reviews the history of the woolly mammoth ( Mammuthus primigenius Blum.) in Siberia and adjacent northern Asia. The particular emphases are the chronology and environment of mammoth existence and extinction, based on about 530 radiocarbon dates from about 230 localities with mammoth remains and palaeoenvironmental records of the last 50,000 years. Until ca. 12,000 radiocarbon years ago (BP), mammoths inhabited all of northern Asia, from the High Arctic to southern Siberia and northeastern China. Since ca. 12,000 BP, mammoth disappeared from major parts of Siberia and adjacent northern Asia, and survived mainly in the Arctic regions of Siberia, north of 69° northern latitude. However, recently, it was found that some mammoth populations continued to exist in central and southern Western Siberia until ca. 11,100-10,200 BP. 'Normal' size mammoths became extinct in mainland Siberia at the Pleistocene-Holocene boundary, ca. 9700 BP. On Wrangel Island in the High Arctic, small-sized mammoths survived into the Middle-Late Holocene, ca. 7700-3700 BP. Compared with previous studies, it is now possible to reveal the complex nature of the process of final mammoth extinction in Siberia, with some small populations surviving outside of the Arctic until ca. 10,000 BP. The extinction of mammoth was most probably caused by a combination of factors, such as global warming in the Late Glacial (since ca. 15,000 BP) and the disintegration of landscapes suitable for mammoths throughout the Upper Pleistocene, such as light forests with vast open spaces occupied by meadows and forest tundra. The expansion of forest vegetation after the Last Glacial Maximum in Siberia, including its northeastern part, created unsuitable habitats for herbivorous megafauna, especially for mammoths. However, the Holocene environment of Wrangel Island was not of 'glacial' type and this requires further studies. The relationship between mammoths and Upper Palaeolithic humans is also considered. The

  17. New Radiocarbon Dates on Upper Mid-West Proboscideans: Determining Date Robustness

    NASA Astrophysics Data System (ADS)

    Hodgins, G.; Widga, C.; Lengyel, S. N.; Saunders, J.; Walker, J. D.

    2013-12-01

    With the objective of refining the picture of Megafaunal extinction patterns in the upper Midwest in the terminal Pleistocene, we have assembled for radiocarbon dating specimens from more than 80 distinct Mammut and Mammuthus remains from potentially late sites. So far, we have measurements for 65 bones, tusks and teeth, nearly double the extant number of published dates . These new specimens were all from museums rather than excavation sites, and 60% were known to be coated with a consolidant. The predominant consolidant was Butvar B-76, however shellac, Elmer's Glue, Glyptol were also noted in the conservation records, or deduced from knowledge of a particular museum's practices. Given the objective of the project is to identify extinction patterns, coupled with the wide prevalence of consolidants amongst the specimen set, it was imperative that testing be carried out to confirm that radiocarbon laboratory protocols removed the consolidants, so that ultimately the dates can be considered robust. To this end, key specimens were dated three times using different sample preparation protocols. These were 1) a solvent extraction followed by a modified Longin-plus -Base continuous flow collagen extraction method used in the NSF-Arizona AMS facility, 2) the solvent/modified Longin method plus ultrafiltration, and 3) solvent/modified Longin method plus hydroxyproline single amino acid dating. Among the specimens subjected to triplicate testing were some of the youngest late Wisconsin proboscidean specimens from the Upper Midwest Region. The data reveal general agreement between the different protocols, and suggested either limited penetration of consolidants into the specimens, or that the standard laboratory cleaning protocols were sufficient to remove traces from deep within bone, tooth or tusk tissue. The preservation of each specimen, recorded in terms of collagen content, C/N ratio and stable isotope values, indicated that most were actually well preserved, implying

  18. Allometric disparity in rodent evolution

    PubMed Central

    Wilson, Laura A B

    2013-01-01

    In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results indicate that the evolution of allometric trajectories in rodents is characterized by different features in sciurids compared with muroids and Ctenohystrica. Sciuridae was found to have a reduced magnitude of inter-trajectory change and growth patterns with less variation in allometric coefficient values among members. In contrast, a greater magnitude of difference between trajectories and an increased variation in allometric coefficient values was evident for both Ctenohystrica and muroids. Ctenohystrica and muroids achieved considerably higher adult disparities than sciurids, suggesting that conservatism in allometric trajectory modification may constrain morphological diversity in rodents. The results provide support for a role of ecology (dietary habit) in the evolution of allometric trajectories in rodents. PMID:23610638

  19. Disparities in Pediatric Obesity in the United States12

    PubMed Central

    Wang, Youfa

    2011-01-01

    This paper describes the disparities in the U.S. childhood obesity epidemic, mainly based on recent nationally representative data. The prevalence of overweight and obesity has increased since the late 1970s; the over time shifts (changes) in distributions of various body fatness measures indicate that U.S. children have become fatter and the obese groups gained more body fat, especially more central obesity, as indicated by waist circumference. However, considerable between-group and regional disparities exist in the prevalence, fatness measures, and over time trends. The disparities and trends are complex, which reflects the complexity and dynamics in obesity etiology. Clearly, some population groups are affected more seriously than others. Native American children have the highest prevalence of obesity, whereas Asians have the lowest rate among all ethnic groups. Preschool age children have a lower obesity prevalence than older children. Young people in some states and cities are twice more likely to be overweight or obese than those living in other regions. Low-socioeconomic status is associated with obesity only among some population groups, e.g. white children and adolescents. Vigorous, effective interventions are needed to promote healthy lifestyles among U.S. young people and to reduce disparities in obesity. PMID:22211187

  20. What Can Radiocarbon Depth Profiles Tell Us About The LGM Circulation?

    NASA Astrophysics Data System (ADS)

    Burke, A.; Stewart, A.; Adkins, J. F.; Ferrari, R. M.; Thompson, A. F.; Jansen, M. F.

    2014-12-01

    Published reconstructions of radiocarbon in the Atlantic sector of the Southern Ocean indicate that there is a mid-depth maximum in radiocarbon age during the last glacial maximum (LGM). This is in contrast to the modern ocean where intense mixing between water masses along shared density surfaces (isopycnals) results in a relatively homogenous radiocarbon profile. A recent study (Ferrari et al. 2014) suggested that the extended Antarctic sea ice cover during the LGM necessitated a shallower boundary between the upper and lower branches of the meridional overturning circulation (MOC). This shoaled boundary lay above major topographic features and their associated strong diapycnal mixing, which isolated dense southern-sourced water in the lower branch of the overturning circulation. This isolation would have allowed radiocarbon to decay, and thus provides a possible explanation for the mid-depth radiocarbon age bulge. We test this hypothesis using an idealized, 2D, residual-mean dynamical model of the global overturning circulation. Concentration distributions of a decaying tracer that is advected by the simulated overturning are compared to published radiocarbon data. We test the sensitivity of the mid-depth radiocarbon age to changes in sea ice extent, wind strength, and isopycnal and diapycnal diffusion. The mid-depth radiocarbon age bulge is most likely caused by the different circulation geometry, associated with increased sea ice extent. In particular, with an LGM-like sea ice extent the upper and lower branches of the MOC no longer share isopycnals, so radiocarbon-rich northern-sourced water is no longer mixed rapidly into the southern-sourced water. However, this process alone cannot explain the magnitude of the glacial radiocarbon anomalies; additional isolation (e.g. from reduced air-sea gas exchange associated with the increased sea ice) is required. Ferrari, R., M. F. Jansen, J. F. Adkins, A. Burke, A. L. Stewart, and A. F. Thompson (2014), Antarctic sea

  1. Radiocarbon ages of soil charcoals from the southern Alps, Ticino, Switzerland

    NASA Astrophysics Data System (ADS)

    Hajdas, Irka; Schlumpf, Nadia; Minikus-Stary, Nicole; Hagedorn, Frank; Eckmeier, Eileen; Schoch, Werner; Burga, Conradin; Bonani, Georges; Schmidt, Michael W. I.; Cherubini, Paolo

    2007-06-01

    Radiocarbon dating of macroscopic charcoal is a useful tool for paleoclimatic and paleoecologic reconstructions. Here we present results of 14C dating of charcoals found in charcoal-rich soils of Ticino and the Misox Valley (southern Switzerland) which indicate that the Late Glacial and early Holocene fires coincided with warm phases in the North Atlantic region and low lake levels in the Central Europe. Late Holocene charcoals found in these soils document an earlier than believed presence of sweet chestnut (Castanea sativa Mill.) in southern Switzerland. Sweet chestnut trees play a key role in Mediterranean woodlands, and for longer than two millennia have been used as a food source. Based on palynological evidence it is commonly believed that in southern Switzerland C. sativa was first introduced 2000 years ago by the Romans, who cultivated it for wood and fruit production. Our results indicate that this tree species was present on the southern slopes of the Alps ∼1500 years earlier than previously assumed, and therefore was likely introduced independently from cultivation by the Romans.

  2. Hydrological and climatological controls on radiocarbon concentrations in a tropical stalagmite

    NASA Astrophysics Data System (ADS)

    Lechleitner, Franziska A.; Baldini, James U. L.; Breitenbach, Sebastian F. M.; Fohlmeister, Jens; McIntyre, Cameron; Goswami, Bedartha; Jamieson, Robert A.; van der Voort, Tessa S.; Prufer, Keith; Marwan, Norbert; Culleton, Brendan J.; Kennett, Douglas J.; Asmerom, Yemane; Polyak, Victor; Eglinton, Timothy I.

    2016-12-01

    Precisely-dated stalagmites are increasingly important archives for the reconstruction of terrestrial paleoclimate at very high temporal resolution. In-depth understanding of local conditions at the cave site and of the processes driving stalagmite deposition is of paramount importance for interpreting proxy signals incorporated in stalagmite carbonate. Here we present a sub-decadally resolved dead carbon fraction (DCF) record for a stalagmite from Yok Balum Cave (southern Belize). The record is coupled to parallel stable carbon isotope (δ13C) and U/Ca measurements, as well as radiocarbon (14C) measurements from soils overlying the cave system. Using a karst carbon cycle model we disentangle the importance of soil and karst processes on stalagmite DCF incorporation, revealing a dominant host rock dissolution control on total DCF. Covariation between DCF, δ13C, and U/Ca indicates that karst processes are a common driver of all three parameters, suggesting possible use of δ13C and trace element ratios to independently quantify DCF variability. A statistically significant multi-decadal lag of variable length exists between DCF and reconstructed solar activity, suggesting that solar activity influenced regional precipitation in Mesoamerica over the past 1500 years, but that the relationship was non-static. Although the precise nature of the observed lag is unclear, solar-induced changes in North Atlantic oceanic and atmospheric dynamics may play a role.

  3. It takes two: New constraints on Cordilleran Ice Sheet extent and retreat from 10Be and radiocarbon dating

    NASA Astrophysics Data System (ADS)

    Lesnek, A. J.; Briner, J. P.

    2016-12-01

    Precisely constraining the timing of marine ice sheet advance and retreat provides important insight into the processes that drive change on these sensitive margins. Here, we reconstruct the latest Pleistocene activity of the Cordilleran Ice Sheet (CIS) in southeastern (SE) Alaska. This marine-terminating region of the CIS, which spanned 500 km of the north Pacific coast, is analogous to marine margins in Greenland and Antarctica and may have possessed coastal ice-free areas (refugia) that served as "stepping stones" for early human migration to the Americas. Yet despite the region's potential role in the peopling of the Americas and its similarity to modern ice margins, well-dated records of its late Pleistocene glacial history are lacking. To address this matter, 13 bedrock and boulder samples were collected from potential refugia SE Alaska for 10Be exposure dating. The eight 10Be ages that have been obtained thus far reveal that the outer islands of SE Alaska were covered by the CIS until 17 ka, when sea surface temperatures along the north Pacific coast were rapidly increasing. Additionally, we have calibrated for the first time 134 previously published radiocarbon ages from SE Alaskan cave fossils, and the results reveal a nearly continuous fossil record that spans from the limit of the radiocarbon dating method to the present. However, none of the cave fossils yielded ages between 19.8 and 17.2 cal kyr BP. Taken together, the results of our 10Be and radiocarbon dating suggest that (1) in contrast to previous reconstructions, the CIS occupied the outer islands of SE Alaska from 20-17 ka and (2) the retreat of its marine margin was triggered by ocean warming. Although we have yet to find evidence of refugia, SE Alaska deglaciated 1 kyr prior to the first pulse of human migration to the Americas at 16 ka, and therefore the region may have indeed served as a "stepping stone" to the New World. This project is ongoing, and future work will focus on generating a

  4. Racial disparities in reaching the renal transplant waitlist: is geography as important as race?

    PubMed Central

    Saunders, Milda R.; Lee, Haena; Alexander, G. Caleb; Tak, Hyo Jung; Thistlethwaite, J. Richard; Ross, Lainie Friedman

    2016-01-01

    Background In the United States, African Americans and whites differ in access to the deceased donor renal transplant waitlist. The extent to which racial disparities in waitlisting differ between United Network for Organ Sharing (UNOS) regions is understudied. Methods The US Renal Data System (USRDS) was linked with US census data to examine time from dialysis initiation to waitlisting for whites (n = 188 410) and African Americans (n = 144 335) using Cox proportional hazards across 11 UNOS regions, adjusting for potentially confounding individual, neighborhood, and state characteristics. Results Likelihood of waitlisting varies significantly by UNOS region, overall and by race. Additionally, African Americans face significantly lower likelihood of waitlisting compared to whites in all but two regions (1 and 6). Overall, 39% of African Americans with ESRD reside in Regions 3 and 4 – regions with a large racial disparity and where African Americans comprise a large proportion of the ESRD population. In these regions, the African American–white disparity is an important contributor to their overall regional disparity. Conclusions Race remains an important factor in time to transplant waitlist in the United States. Race contributes to overall regional disparities; however, the importance of race varies by UNOS region. PMID:25818547

  5. Racial disparities in reaching the renal transplant waitlist: is geography as important as race?

    PubMed

    Saunders, Milda R; Lee, Haena; Alexander, G Caleb; Tak, Hyo Jung; Thistlethwaite, J Richard; Ross, Lainie Friedman

    2015-06-01

    In the United States, African Americans and whites differ in access to the deceased donor renal transplant waitlist. The extent to which racial disparities in waitlisting differ between United Network for Organ Sharing (UNOS) regions is understudied. The US Renal Data System (USRDS) was linked with US census data to examine time from dialysis initiation to waitlisting for whites (n = 188,410) and African Americans (n = 144,335) using Cox proportional hazards across 11 UNOS regions, adjusting for potentially confounding individual, neighborhood, and state characteristics. Likelihood of waitlisting varies significantly by UNOS region, overall and by race. Additionally, African Americans face significantly lower likelihood of waitlisting compared to whites in all but two regions (1 and 6). Overall, 39% of African Americans with ESRD reside in Regions 3 and 4--regions with a large racial disparity and where African Americans comprise a large proportion of the ESRD population. In these regions, the African American-white disparity is an important contributor to their overall regional disparity. Race remains an important factor in time to transplant waitlist in the United States. Race contributes to overall regional disparities; however, the importance of race varies by UNOS region. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. The Importance of Geographic Data Aggregation in Assessing Disparities in American Indian Prenatal Care

    PubMed Central

    Call, Kathleen Thiede; Blewett, Lynn A.

    2010-01-01

    Objectives. We sought to determine whether aggregate national data for American Indians/Alaska Natives (AIANs) mask geographic variation and substantial subnational disparities in prenatal care utilization. Methods. We used data for US births from 1995 to 1997 and from 2000 to 2002 to examine prenatal care utilization among AIAN and non-Hispanic White mothers. The indicators we studied were late entry into prenatal care and inadequate utilization of prenatal care. We calculated rates and disparities for each indicator at the national, regional, and state levels, and we examined whether estimates for regions and states differed significantly from national estimates. We then estimated state-specific changes in prevalence rates and disparity rates over time. Results. Prenatal care utilization varied by region and state for AIANs and non-Hispanic Whites. In the 12 states with the largest AIAN birth populations, disparities varied dramatically. In addition, some states demonstrated substantial reductions in disparities over time, and other states showed significant increases in disparities. Conclusions. Substantive conclusions about AIAN health care disparities should be geographically specific, and conclusions drawn at the national level may be unsuitable for policymaking and intervention at state and local levels. Efforts to accommodate the geographically specific data needs of AIAN health researchers and others interested in state-level comparisons are warranted. PMID:19910356

  7. Radiocarbon Based Ages and Growth Rates: Hawaiian Deep Sea Corals

    SciTech Connect

    Roark, E B; Guilderson, T P; Dunbar, R B; Ingram, B L

    2006-01-13

    The radial growth rates and ages of three different groups of Hawaiian deep-sea 'corals' were determined using radiocarbon measurements. Specimens of Corallium secundum, Gerardia sp., and Leiopathes glaberrima, were collected from 450 {+-} 40 m at the Makapuu deep-sea coral bed using a submersible (PISCES V). Specimens of Antipathes dichotoma were collected at 50 m off Lahaina, Maui. The primary source of carbon to the calcitic C. secundum skeleton is in situ dissolved inorganic carbon (DIC). Using bomb {sup 14}C time markers we calculate radial growth rates of {approx} 170 {micro}m y{sup -1} and ages of 68-75 years on specimens as tall as 28 cm of C. secundum. Gerardia sp., A. dichotoma, and L. glaberrima have proteinaceous skeletons and labile particulate organic carbon (POC) is their primary source of architectural carbon. Using {sup 14}C we calculate a radial growth rate of 15 {micro}m y{sup -1} and an age of 807 {+-} 30 years for a live collected Gerardia sp., showing that these organisms are extremely long lived. Inner and outer {sup 14}C measurements on four sub-fossil Gerardia spp. samples produce similar growth rate estimates (range 14-45 {micro}m y{sup -1}) and ages (range 450-2742 years) as observed for the live collected sample. Similarly, with a growth rate of < 10 {micro}m y{sup -1} and an age of {approx}2377 years, L. glaberrima at the Makapuu coral bed, is also extremely long lived. In contrast, the shallow-collected A. dichotoma samples yield growth rates ranging from 130 to 1,140 {micro}m y{sup -1}. These results show that Hawaiian deep-sea corals grow more slowly and are older than previously thought.

  8. Intermediate Water Radiocarbon Anomalies During the Last Deglaciation

    NASA Astrophysics Data System (ADS)

    Bryan, S. P.; Lehman, S. J.; Marchitto, T. M.; Ninnemann, U. S.

    2011-12-01

    Several recent reconstructions of intermediate water radiocarbon activities (Δ14C) have revealed intervals of very low Δ14C during the last deglaciation [Bryan et al., 2010; Marchitto et al., 2007; Thornalley et al., 2011]. Anomalously low Δ14C values coincided with increases in atmospheric CO2 and decreases in atmospheric Δ14C. As such, these Δ14C anomalies have been interpreted as the transfer of 14C-depleted carbon from the deep ocean to the upper ocean and atmosphere. An important component of this interpretation is the transport of low-Δ14C waters from the Southern Ocean, where they presumably upwelled from the deep ocean, northward to the core sites via intermediate waters. However, contrary to expectations, anomalously low Δ14C values have not been found at intermediate water sites closer to the Southern Ocean [e.g., De Pol-Holz et al., 2009; Rose et al., 2010]. In this talk, we will present new intermediate water Δ14C measurements from ~53°S along the Chile Margin, reconstructed using sediment core MD07-3128. Consistent with other intermediate water records from the Southern Hemisphere, these measurements do not show anomalously low Δ14C during the deglaciation. Instead, these results indicate lower Δ14C values during the Last Glacial Maximum and a rapid increase in Δ14C at the start of the deglaciation. We interpret this change as a shift in the boundary between Circumpolar Deep Water and Antarctic Intermediate Water. These results along with the previously published records provide strong evidence that low-Δ14C waters were not transported by an intermediate water mass analogous to modern Antarctic Intermediate Water. We synthesize the currently available deglacial intermediate water Δ14C records and discuss possible changes to Southern Ocean intermediate water formation, which could reconcile the available data.

  9. Determination of radiocarbon in stratospheric CO2, obtained through AirCore sampling.

    NASA Astrophysics Data System (ADS)

    Paul, Dipayan; Chen, Huilin; Been, Henk A.; Kivi, Rigel; Meijer, Harro A. J.

    2016-04-01

    The concentration of Greenhouse Gases (GHG), with carbon dioxide as the most prominent example, has been and still is increasing, predominantly due to emissions from fossil fuel combustion. CO2 is also the most important component of the global carbon cycle. Among other tracers, radiocarbon (Carbon-14) is a unique and an important atmospheric tracer used in the understanding of the global carbon cycle. Radiocarbon is a naturally occurring isotope (radioactive, t 1/2 = 5730 ± 40 years) of carbon produced through the interaction of thermalized neutrons and nitrogen in the upper atmosphere. Generally, for performing atmospheric radiocarbon measurements in the higher atmosphere, large samples (few liters of air) were collected using aircrafts and balloons. However, collecting stratospheric samples on a regular basis for radiocarbon analysis is extremely expensive. Here we describe the determination of radiocarbon concentrations in stratospheric CO2, collected using AirCore sampling. AirCore is an innovative sampling technique for obtaining vertical atmospheric profiles and, in Europe, is done on a regular basis at Sodankylä, Finland for CO2, CH4 and CO. The stratospheric parts of two such AirCore profiles were used in this study as a proof-of-principle. CO2 from the stratospheric air samples were extracted and converted to elemental carbon, which were then measured at the Accelerator Mass Spectrometric (AMS) facility of the Centre for Isotope Research (CIO) at the University of Groningen. The stratospheric part of the AirCore profile was divided into six sections, each contained approximately 10 μg C. A detailed description of the extraction, graphitization, AMS analysis and the derivation of the stratospheric radiocarbon profile will be the main focus. Through our results, we will show that AirCore is a viable sampling method for performing high-precision radiocarbon measurements of stratospheric CO2 with reasonably good spatial resolution on a regular basis

  10. Intracavity optogalvanic spectroscopy: Is there any evidence of a radiocarbon signal?

    NASA Astrophysics Data System (ADS)

    Persson, Anders; Salehpour, Mehran

    2015-10-01

    In 2008, the first report of an ultrasensitive method for ro-vibrational spectrometry of radiocarbon dioxide was published. The method, called intracavity optogalvanic spectroscopy (ICOGS), claimed a sensitivity and limit-of-detection comparable to accelerator mass spectroscopy. ICOGS was claimed to utilize the isotope-dependent ro-vibrational absorption lines of carbon dioxide in the infrared spectrum. In order to facilitate unambiguous detection of radiocarbon, the sample was placed inside the cavity of a radiocarbon dioxide laser. This intracavity approach was claimed to increase the sensitivity by seven orders of magnitude compared with traditional optogalvanic methods. However, despite the methodical and thorough efforts of several research groups worldwide, these claims have not been possible to reproduce. Instead, we have previously reported serious deviations from the original results, where we found that ICOGS suffers from considerable problems with the stability and reproducibility of the optogalvanic signal, and that misinterpretations of these uncertainties likely are the explanation for the claimed sensitivity in the first reports. Having identified the stability and reproducibility of the detection as major concerns, we decided to improve the setup by with state-of-the-art plasma source technology. Deploying a custom-made stripline split-ring resonator optogalvanic detector, we have now investigated the applicability of ICOGS to radiocarbon detection even further. Measurements have been made with a wide range of parameters including different gas mixtures at various pressures and wavelengths. We have also conducted measurements with gas flowing through the sample cell to investigate the effect of plasma induced decomposition of the sample. Still, we have seen no indications of a significant radiocarbon signal in a concentration range between 0.29 Modern and 9.7 Modern, i.e., the range of interest to the radiocarbon community. Hence, our conclusions

  11. What is the true age uncertainty of radiocarbon dated Holocene records?

    NASA Astrophysics Data System (ADS)

    Ho, Sze Ling; Groeneveld, Jeroen; Refeld, Kira; Mollenhauer, Gesine; De Pol-Holz, Ricardo; Nürnberg, Dirk; Laepple, Thomas

    2016-04-01

    Radiocarbon-based age-depth models are the backbone of the chronology of Holocene sediment records. The uncertainty of such age-depth models is often estimated from the uncertainty of the calibrated radiocarbon samples. A necessary assumption hereby is that the age of the samples is representative for the proxies in the same sediment layer they originate from. Here we generate radiocarbon and multiple temperature proxy data in three Holocene sediment cores from the same multi-corer employed in the Southwest Pacific. Surprisingly, whilst radiocarbon ages at the same sediment depth strongly differ between the tubes, multiple independent proxy time-series measured in each of the sediment cores suggest stratified sediments at the site. This is based on the finding that proxy time-series correlate significantly better between sediment cores when analyzed over depth, rather than against core-specific age-depth models based on the radiocarbon dates. If our site is not a pathological special case - an argument which we have no evidence for - our finding has important implications for age-depth modeling and the interpretations of paleoclimate time-series. It suggests that the true age uncertainty of a sediment layer can be much higher than the uncertainty obtained from the radiocarbon dates. An alternative but less likely hypothesis is that the proxy values are modified post-deposition in the sediments, resulting in more consistent stratification than the original climate signal time-series. Our study demonstrates the usefulness of replication of the proxy time series and radiocarbon dates in the quest for chronologic precision and proxy reliability, which are crucial for a more quantitative understanding of Holocene climate evolution.

  12. Holocene Radiocarbon Dates on Coexisting Benthic and Planktic Foraminifera Shells in the Subarctic North Pacific

    NASA Astrophysics Data System (ADS)

    Davies, M. H.; Mix, A. C.; Stoner, J. S.; Southon, J.

    2008-12-01

    The high North Pacific contains some of the oldest and CO2-rich deep waters in the world; however, variations of the interactions between the surface and subsurface reservoirs and the ice-age history of both land and ocean remain poorly known. Here we present paired planktic and benthic foraminifera radiocarbon dates from jumbo piston cores taken on the Gulf of Alaska margin. The present focus of this research is core EW0408-85JC (59.56° N, 144.15° W, 682 m depth), located on the shelf break at a depth shallow enough to avoid carbonate dissolution, yet still experiencing oceanic conditions as confirmed by the oxygen isotope record. The core extends back >17,000 ybp; sedimentation rates implied by the high- resolution dating vary from an early Holocene low of ~20 cm/ka, to late glacial values of >500 cm/ka (likely associated with rapid flux of glacial silt to the ocean). Regional retreat of glaciers behind fjord sills is constrained to >16 ka (calendar). Benthic-planktic 14C age differences (B-P) mostly track values expected from changing atmospheric production rates as they propagate into the ocean system, with a modern B-P of 500 yr. Exceptions include high B-P values of ~800 yr in mid-Holocene time. This interval is associated with reduced percentages of the foraminiferal species G. bulloides, implying greater upper- ocean stratification or weaker upwelling than at present. High B-P values during glaciation, up to ~1000 yr, may reflect the presence of relatively old subsurface waters (i.e. no apparent increase in shallow subsurface ventilation by intermediate waters during glacial time in this region), and/or increased stratification associated with freshwater inputs from regional tidewater glaciers.

  13. Stereo transparency and the disparity gradient limit

    NASA Technical Reports Server (NTRS)

    McKee, Suzanne P.; Verghese, Preeti

    2002-01-01

    Several studies (Vision Research 15 (1975) 583; Perception 9 (1980) 671) have shown that binocular fusion is limited by the disparity gradient (disparity/distance) separating image points, rather than by their absolute disparity values. Points separated by a gradient >1 appear diplopic. These results are sometimes interpreted as a constraint on human stereo matching, rather than a constraint on fusion. Here we have used psychophysical measurements on stereo transparency to show that human stereo matching is not constrained by a gradient of 1. We created transparent surfaces composed of many pairs of dots, in which each member of a pair was assigned a disparity equal and opposite to the disparity of the other member. For example, each pair could be composed of one dot with a crossed disparity of 6' and the other with uncrossed disparity of 6', vertically separated by a parametrically varied distance. When the vertical separation between the paired dots was small, the disparity gradient for each pair was very steep. Nevertheless, these opponent-disparity dot pairs produced a striking appearance of two transparent surfaces for disparity gradients ranging between 0.5 and 3. The apparent depth separating the two transparent planes was correctly matched to an equivalent disparity defined by two opaque surfaces. A test target presented between the two transparent planes was easily detected, indicating robust segregation of the disparities associated with the paired dots into two transparent surfaces with few mismatches in the target plane. Our simulations using the Tsai-Victor model show that the response profiles produced by scaled disparity-energy mechanisms can account for many of our results on the transparency generated by steep gradients.

  14. Stereo transparency and the disparity gradient limit

    NASA Technical Reports Server (NTRS)

    McKee, Suzanne P.; Verghese, Preeti

    2002-01-01

    Several studies (Vision Research 15 (1975) 583; Perception 9 (1980) 671) have shown that binocular fusion is limited by the disparity gradient (disparity/distance) separating image points, rather than by their absolute disparity values. Points separated by a gradient >1 appear diplopic. These results are sometimes interpreted as a constraint on human stereo matching, rather than a constraint on fusion. Here we have used psychophysical measurements on stereo transparency to show that human stereo matching is not constrained by a gradient of 1. We created transparent surfaces composed of many pairs of dots, in which each member of a pair was assigned a disparity equal and opposite to the disparity of the other member. For example, each pair could be composed of one dot with a crossed disparity of 6' and the other with uncrossed disparity of 6', vertically separated by a parametrically varied distance. When the vertical separation between the paired dots was small, the disparity gradient for each pair was very steep. Nevertheless, these opponent-disparity dot pairs produced a striking appearance of two transparent surfaces for disparity gradients ranging between 0.5 and 3. The apparent depth separating the two transparent planes was correctly matched to an equivalent disparity defined by two opaque surfaces. A test target presented between the two transparent planes was easily detected, indicating robust segregation of the disparities associated with the paired dots into two transparent surfaces with few mismatches in the target plane. Our simulations using the Tsai-Victor model show that the response profiles produced by scaled disparity-energy mechanisms can account for many of our results on the transparency generated by steep gradients.

  15. The Persistence of American Indian Health Disparities

    PubMed Central

    Jones, David S.

    2006-01-01

    Disparities in health status between American Indians and other groups in the United States have persisted throughout the 500 years since Europeans arrived in the Americas. Colonists, traders, missionaries, soldiers, physicians, and government officials have struggled to explain these disparities, invoking a wide range of possible causes. American Indians joined these debates, often suggesting different explanations. Europeans and Americans also struggled to respond to the disparities, sometimes working to relieve them, sometimes taking advantage of the ill health of American Indians. Economic and political interests have always affected both explanations of health disparities and responses to them, influencing which explanations were emphasized and which interventions were pursued. Tensions also appear in ongoing debates about the contributions of genetic and socioeconomic forces to the pervasive health disparities. Understanding how these economic and political forces have operated historically can explain both the persistence of the health disparities and the controversies that surround them. PMID:17077399

  16. Empowerment to reduce health disparities.

    PubMed

    Wallerstein, Nina

    2002-01-01

    This article articulates the theoretical construct of empowerment and its importance for health-enhancing strategies to reduce health disparities. Powerlessness is explored as a risk factor in the context of social determinants, such as poverty, discrimination, workplace hazards, and income inequities. Empowerment is presented and compared with social capital and community capacity as strategies to strengthen social protective factors. A case study of a youth empowerment and policy project in New Mexico illustrates the usefulness of empowerment strategies in both targeting social determinants, such as public policies which are detrimental to youth, and improving community capacities of youth to be advocates for social change. Challenges for future practice and research are articulated.

  17. Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

    PubMed Central

    Boyd, Thomas J.; Montgomery, Michael T.; Cuenca, Richard H.; Hagimoto, Yutaka

    2016-01-01

    A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate the environment. This radiocarbon signal — or rather the absence of signal — is evenly distributed throughout a contaminant source pool (unlike an added tracer) and is not impacted by biological, chemical or physical processes (e.g., the 14C radioactive decay rate is immutable). If the fossil-derived contaminant is fully degraded to CO2, a harmless end-product, that CO2 will contain no radiocarbon. CO2 derived from natural organic matter (NOM) degradation will reflect the NOM radiocarbon content (usually <30,000 years old). Given a known radiocarbon content for NOM (a site background), a two end-member mixing model can be used to determine the CO2 derived from a fossil source in a given soil gas or groundwater sample. Coupling the percent CO2 derived from the contaminant with the CO2 respiration rate provides an estimate for the total amount of contaminant degraded per unit time. Finally, determining a zone of influence (ZOI) representing the volume from which site CO2 is collected allows determining the contaminant degradation per unit time and volume. Along with estimates for total contaminant mass, this can ultimately be used to calculate time-to-remediate or otherwise used by site managers for decision-making. PMID:27805601

  18. Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses.

    PubMed

    Boyd, Thomas J; Montgomery, Michael T; Cuenca, Richard H; Hagimoto, Yutaka

    2016-10-21

    A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate the environment. This radiocarbon signal - or rather the absence of signal - is evenly distributed throughout a contaminant source pool (unlike an added tracer) and is not impacted by biological, chemical or physical processes (e.g., the (14)C radioactive decay rate is immutable). If the fossil-derived contaminant is fully degraded to CO2, a harmless end-product, that CO2 will contain no radiocarbon. CO2 derived from natural organic matter (NOM) degradation will reflect the NOM radiocarbon content (usually <30,000 years old). Given a known radiocarbon content for NOM (a site background), a two end-member mixing model can be used to determine the CO2 derived from a fossil source in a given soil gas or groundwater sample. Coupling the percent CO2 derived from the contaminant with the CO2 respiration rate provides an estimate for the total amount of contaminant degraded per unit time. Finally, determining a zone of influence (ZOI) representing the volume from which site CO2 is collected allows determining the contaminant degradation per unit time and volume. Along with estimates for total contaminant mass, this can ultimately be used to calculate time-to-remediate or otherwise used by site managers for decision-making.

  19. Shape analysis of probability distribution functions in relation to UK Holocene radiocarbon dated fluvial units

    NASA Astrophysics Data System (ADS)

    Moloney, Jessica; Coutlhard, Tom; Freer, Jim; Rogerson, Mike

    2017-04-01

    Flood frequency records are important to place current flooding events into a long-term perspective. To achieve this, geomorphological evidence from fluvial depositional environments can be used. Organic material, which can be radiocarbon dated, can provide evidence that can be interpreted as dated flood events. In the UK, there is a collection of radiocarbon dated fluvial units dated for the Holocene has been used to create a flood frequency record. Previously, the flood frequency record for the UK has been criticised because of the uncertainties associated with summed probability distribution plots. There are factors that can affect the shape of a probability distribution function: the number of dates in total, the temporal distribution of dates, the radiocarbon laboratory error value and the geomorphological location of the sample however it is unknown how each of these factors influence the shape of the probability distribution curve created using the UK database. This study examines to what extent these factors influence the shape of a PDF in relation to the UK database of radiocarbon dated fluvial units. This study reports the results of a statistical analysis of 745 radiocarbon dates for reconstruction of flood frequency.

  20. Radiocarbon Generation By Cosmic Rays and Elements Transport, Mixing and Exchange On The Earth

    NASA Astrophysics Data System (ADS)

    Dorman, L. I.

    We considere general equations and its solutions determined the space-time varia- tions of cosmogenic nuclides production by cosmic rays (CR) and its contents in the space, inside astrophysical bodies, in atmospheres of stares and planets by the method of coupling functions which was developed before for CR variations research. Then we introduce and calculate the local and polar radiocarbon coupling functions for the Earth's atmosphere with taking into account vertical mixing of elements. Then we introduce and calculate the global radiocarbon coupling function with taking into ac- count the global elements transport, mixing and influence of geomagnetic field on CR planetary distribution. For the contents of radiocarbon in the atmosphere and in dated samples are very important exchange processes between several reservoirs on the Earth. As the first approximation we consider two-reservoir model and then the model of five-reservoir elements exchange. By comparison with experimental data on radiocarbon contents we estimate the exchange constants. On the basis of devel- oped methods and obtained solutions of equations determined the time evolution of radiocarbon production rate and contents in the Earth's atmosphere we consider data of atomic bomb tests in the atmosphere, on CR time variations in the past caused by changes of geomagnetic field, by solar activity cycles, and by possible local supernova explosions

  1. Accurate radiocarbon age estimation using "early" measurements: a new approach to reconstructing the Paleolithic absolute chronology

    NASA Astrophysics Data System (ADS)

    Omori, Takayuki; Sano, Katsuhiro; Yoneda, Minoru

    2014-05-01

    This paper presents new correction approaches for "early" radiocarbon ages to reconstruct the Paleolithic absolute chronology. In order to discuss time-space distribution about the replacement of archaic humans, including Neanderthals in Europe, by the modern humans, a massive data, which covers a wide-area, would be needed. Today, some radiocarbon databases focused on the Paleolithic have been published and used for chronological studies. From a viewpoint of current analytical technology, however, the any database have unreliable results that make interpretation of radiocarbon dates difficult. Most of these unreliable ages had been published in the early days of radiocarbon analysis. In recent years, new analytical methods to determine highly-accurate dates have been developed. Ultrafiltration and ABOx-SC methods, as new sample pretreatments for bone and charcoal respectively, have attracted attention because they could remove imperceptible contaminates and derive reliable accurately ages. In order to evaluate the reliability of "early" data, we investigated the differences and variabilities of radiocarbon ages on different pretreatments, and attempted to develop correction functions for the assessment of the reliability. It can be expected that reliability of the corrected age is increased and the age applied to chronological research together with recent ages. Here, we introduce the methodological frameworks and archaeological applications.

  2. Analyzing Economic Spatial-Temporal Disparities at County Level in Yangtze River Delta Based on ESDA-GIS

    NASA Astrophysics Data System (ADS)

    Yang, He; Liu, Jin-Ping; Wang, Tao

    Regional economic disparities have been a hot topic in recent academic world. This paper explores the feasibility of coefficient of variance (CV) and exploratory spatial data analysis (ESDA) in investigating the spatial dynamics of regional disparities at county level in Yangtze River Delta by analyzing per capita GDP data from 1999 to 2008. Empirical results show that the overall spatial disparities of regional economy in Yangtze River Delta have been increasing throughout the study period. The polarization effect is beyond its spread effect, which indicates the spatial heterogeneity of the whole regional economy into two different clubs through the process of cumulative causation.

  3. Geographic disparities in colorectal cancer survival

    PubMed Central

    Henry, Kevin A; Niu, Xiaoling; Boscoe, Francis P

    2009-01-01

    Background Examining geographic variation in cancer patient survival can help identify important prognostic factors that are linked by geography and generate hypotheses about the underlying causes of survival disparities. In this study, we apply a recently developed spatial scan statistic method, designed for time-to-event data, to determine whether colorectal cancer (CRC) patient survival varies by place of residence after adjusting survival times for several prognostic factors. Methods Using data from a population-based, statewide cancer registry, we examined a cohort of 25,040 men and women from New Jersey who were newly diagnosed with local or regional stage colorectal cancer from 1996 through 2003 and followed to the end of 2006. Survival times were adjusted for significant prognostic factors (sex, age, stage at diagnosis, race/ethnicity and census tract socioeconomic deprivation) and evaluated using a spatial scan statistic to identify places where CRC survival was significantly longer or shorter than the statewide experience. Results Age, sex and stage adjusted survival times revealed several areas in the northern part of the state where CRC survival was significantly different than expected. The shortest and longest survival areas had an adjusted 5-year survival rate of 73.1% (95% CI 71.5, 74.9) and 88.3% (95% CI 85.4, 91.3) respectively, compared with the state average of 80.0% (95% CI 79.4, 80.5). Analysis of survival times adjusted for age, sex and stage as well as race/ethnicity and area socioeconomic deprivation attenuated the risk of death from CRC in several areas, but survival disparities persisted. Conclusion The results suggest that in areas where additional adjustments for race/ethnicity and area socioeconomic deprivation changed the geographic survival patterns and reduced the risk of death from CRC, the adjustment factors may be contributing causes of the disparities. Further studies should focus on specific and modifiable individual and

  4. The evolution of a disparity decision in human visual cortex

    PubMed Central

    Cottereau, Benoit R.; Ales, Justin M.; Norcia, Anthony M.

    2015-01-01

    We used fMRI-informed EEG source-imaging in humans to characterize the dynamics of cortical responses during a disparity-discrimination task. After the onset of a disparity-defined target, decision-related activity was found within an extended cortical network that included several occipital regions of interest (ROIs): V4, V3A, hMT+ and the Lateral Occipital Complex (LOC). By using a response-locked analysis, we were able to determine the timing relationships in this network of ROIs relative to the subject's behavioral response. Choice-related activity appeared first in the V4 ROI almost 200 ms before the button press and then subsequently in the V3A ROI. Modeling of the responses in the V4 ROI suggests that this area provides an early contribution to disparity discrimination. Choice-related responses were also found after the button-press in ROIs V4, V3A, LOC and hMT+. Outside the visual cortex, choice-related activity was found in the frontal and temporal pole before the button-press. By combining the spatial resolution of fMRI-informed EEG source imaging with the ability to sort out neural activity occurring before, during and after the behavioral manifestation of the decision, our study is the first to assign distinct functional roles to the extra-striate ROIs involved in perceptual decisions based on disparity, the primary cue for depth. PMID:24513152

  5. Prioritizing health disparities in medical education to improve care.

    PubMed

    Awosogba, Temitope; Betancourt, Joseph R; Conyers, F Garrett; Estapé, Estela S; Francois, Fritz; Gard, Sabrina J; Kaufman, Arthur; Lunn, Mitchell R; Nivet, Marc A; Oppenheim, Joel D; Pomeroy, Claire; Yeung, Howa

    2013-05-01

    Despite yearly advances in life-saving and preventive medicine, as well as strategic approaches by governmental and social agencies and groups, significant disparities remain in health, health quality, and access to health care within the United States. The determinants of these disparities include baseline health status, race and ethnicity, culture, gender identity and expression, socioeconomic status, region or geography, sexual orientation, and age. In order to renew the commitment of the medical community to address health disparities, particularly at the medical school level, we must remind ourselves of the roles of doctors and medical schools as the gatekeepers and the value setters for medicine. Within those roles are responsibilities toward the social mission of working to eliminate health disparities. This effort will require partnerships with communities as well as with academic centers to actively develop and to implement diversity and inclusion strategies. Besides improving the diversity of trainees in the pipeline, access to health care can be improved, and awareness can be raised regarding population-based health inequalities. © 2013 New York Academy of Sciences.

  6. Prioritizing health disparities in medical education to improve care

    PubMed Central

    Awosogba, Temitope; Betancourt, Joseph R.; Conyers, F. Garrett; Estapé, Estela S.; Francois, Fritz; Gard, Sabrina J.; Kaufman, Arthur; Lunn, Mitchell R.; Nivet, Marc A.; Oppenheim, Joel D.; Pomeroy, Claire; Yeung, Howa

    2015-01-01

    Despite yearly advances in life-saving and preventive medicine, as well as strategic approaches by governmental and social agencies and groups, significant disparities remain in health, health quality, and access to health care within the United States. The determinants of these disparities include baseline health status, race and ethnicity, culture, gender identity and expression, socioeconomic status, region or geography, sexual orientation, and age. In order to renew the commitment of the medical community to address health disparities, particularly at the medical school level, we must remind ourselves of the roles of doctors and medical schools as the gatekeepers and the value setters for medicine. Within those roles are responsibilities toward the social mission of working to eliminate health disparities. This effort will require partnerships with communities as well as with academic centers to actively develop and to implement diversity and inclusion strategies. Besides improving the diversity of trainees in the pipeline, access to health care can be improved, and awareness can be raised regarding population-based health inequalities. PMID:23659676

  7. Discrete Gabor Filters For Binocular Disparity Measurement

    NASA Technical Reports Server (NTRS)

    Weiman, Carl F. R.

    1995-01-01

    Discrete Gabor filters proposed for use in determining binocular disparity - difference between positions of same feature or object depicted in stereoscopic images produced by two side-by-side cameras aimed in parallel. Magnitude of binocular disparity used to estimate distance from cameras to feature or object. In one potential application, cameras charge-coupled-device video cameras in robotic vision system, and binocular disparities and distance estimates used as control inputs - for example, to control approaches to objects manipulated or to maintain safe distances from obstacles. Binocular disparities determined from phases of discretized Gabor transforms.

  8. Quality of Care and Disparities in Obstetrics.

    PubMed

    Howell, Elizabeth A; Zeitlin, Jennifer

    2017-03-01

    Growing attention is being paid to obstetric quality of care as patients are pressing the health care system to measure and improve quality. There is also an increasing recognition of persistent racial and ethnic disparities prevalent in obstetric outcomes. Yet few studies have linked obstetric quality of care with racial and ethnic disparities. This article reviews definitions of quality of care, health disparities, and health equity as they relate to obstetric care and outcomes; describes current efforts and challenges in obstetric quality measurement; and proposes 3 steps in an effort to develop, track, and improve quality and reduce disparities in obstetrics.

  9. Issues and Methods in Disparities Research

    PubMed Central

    Canino, Glorisa; McQuaid, Elizabeth L.; Alvarez, Maria; Colon, Angel; Esteban, Cynthia; Febo, Vivian; Klein, Robert B.; Mitchell, Daphne Koinis; Kopel, Sheryl J.; Montealegre, Federico; Ortega, Alexander N.; Rodriguez-Santana, Jose; Seifer, Ronald; Fritz, Gregory K.

    2012-01-01

    Summary Background Epidemiologic studies have documented higher rates of asthma prevalence and morbidity in minority children compared to non-Latino white (NLW) children. Few studies focus on the mechanisms involved in explaining this disparity, and fewer still on the methodological challenges involved in rigorous disparities research. Objectives and Methods This article provides an overview of challenges and potential solutions to research design for studies of health disparities. The methodological issues described in this article were framed on an empirical model of asthma health disparities that views disparities as resulting from several factors related to the healthcare system and the individual/community system. The methods used in the Rhode Island–Puerto Rico Asthma Center are provided as examples, illustrating the challenges in executing disparities research. Results Several methods are described: distinguishing ethnic/racial differences from methodological artifacts, identifying and adapting culturally sensitive measures to explain disparities, and addressing the challenges involved in determining asthma and its severity in Latino and other minority children. The measures employed are framed within each of the components of the conceptual model presented. Conclusions Understanding ethnic and/or cultural disparities in asthma morbidity is a complicated process. Methodologic approaches to studying the problem must reflect this complexity, allowing us to move from documenting disparities to understanding them, and ultimately to reducing them. PMID:19658111

  10. Large variations of surface ocean radiocarbon: Evidence of circulation changes in the southwestern Pacific

    NASA Astrophysics Data System (ADS)

    Druffel, Ellen R. M.; Griffin, Sheila

    1993-01-01

    Radiocarbon (Δ14C) and stable isotope (δ18O and δ13C) records are presented for biannual samples from a 323-year banded coral series collected from the southern Great Barrier Reef, Australia. The high-precision Δ14C record contains variations on an interannual timescale, that are particularly large between A.D. 1680 and 1730. By comparison with tree ring Δ14C records [Stuiver and Quay, 1980; M. Stuiver, personal communication, 1992), it is clear that these shifts were not caused by changes in the Δ14C of atmospheric CO2. Changes in vertical mixing and large scale advective changes involving source waters to the western Coral Sea region are likely processes that could account for these large Δ14C variations. Most low Δ14C values for the period A.D. 1635-1875 coincide with El Niño/Southern Oscillation (ENSO) events as reported by Quinn et al. [1987] for the eastern tropical Pacific. However, ENSO does not explain all of the variations, especially during 1875-1920 when Δ14C values remained high. Cross-spectral analysis of the early half of the Δ14C and δ18O records (A.D. 1635-1795) reveals that the 6-year period is coherent; this coherency is not present in the latter half (A.D. 1797-1957) of the isotope records. These data support the concept of century timescale changes in the nature of ENSO, as it is manifest in the southwestern Pacific. Our coral record shows no evidence of a Suess effect, the lowering of Δ14C from late 1800s through 1955 due mainly to CO2 input from fossil fuel burning. This is coincident with the change we observe in the nature of ENSO and is further evidence that a long-term change in mixing of upper waters occurred in this region.

  11. Disparities in ADHD assessment, diagnosis, and treatment.

    PubMed

    Morley, Christopher P

    2010-01-01

    The regional study by Baumgardner and colleagues converges with existing literature to clearly show that the distribution of ADHD diagnosis falls along socioeconomic lines, according to the relative wealth of neighborhoods. This adds additional evidence that trends in the diagnosis and treatment for ADHD in children move in the exact opposite direction from those who are at highest risk for meeting criteria, for experiencing impairment, for and downstream socioeconomic sequelae. Contributing factors, such as marginal diagnoses (such as when parent and teacher symptom reports diverge), inadequate insurance coverage, limited time, and lack of familiarity and comfort with diagnostic and prescribing guidelines, may leave the door open to misdiagnosis and treatment. In some cases, this may take the form of over-diagnosis and over-treatment, in the form of false-positive diagnoses with ADHD, and treatments for it, or may alternatively take the form of false-negative diagnoses. If the social and epidemiological data are any indication, it is furthermore likely that such false-positive or false-negative outcomes may break along socioeconomic lines. Increased use of formal screening tools, increased curricular time for mental health in primary care residencies, support for physicians in the field in the form of referral options and remote consultation and support, may all serve to improve quality of care for individual patients, and may also serve to regularize treatment across socioeconomic and sociodemographic lines, hence reducing disparities. Further research is needed to study the root causes and dynamics that create such disparities, but the steps outlined above may help in the near term.

  12. Radiocarbon dating of small terrestrial gastropod shells in North America

    USGS Publications Warehouse

    Pigati, J.S.; Rech, J.A.; Nekola, J.C.

    2010-01-01

    Fossil shells of small terrestrial gastropods are commonly preserved in wetland, alluvial, loess, and glacial deposits, as well as in sediments at many archeological sites. These shells are composed largely of aragonite (CaCO3) and potentially could be used for radiocarbon dating, but they must meet two criteria before their 14C ages can be considered to be reliable: (1) when gastropods are alive, the 14C activity of their shells must be in equilibrium with the 14C activity of the atmosphere, and (2) after burial, their shells must behave as closed systems with respect to carbon. To evaluate the first criterion, we conducted a comprehensive examination of the 14C content of the most common small terrestrial gastropods in North America, including 247 AMS measurements of modern shell material (3749 individual shells) from 46 different species. The modern gastropods that we analyzed were all collected from habitats on carbonate terrain and, therefore, the data presented here represent worst-case scenarios. In sum, ~78% of the shell aliquots that we analyzed did not contain dead carbon from limestone or other carbonate rocks even though it was readily available at all sites, 12% of the aliquots contained between 5 and 10% dead carbon, and a few (3% of the total) contained more than 10%. These results are significantly lower than the 20-30% dead carbon that has been reported previously for larger taxa living in carbonate terrain. For the second criterion, we report a case study from the American Midwest in which we analyzed fossil shells of small terrestrial gastropods (7 taxa; 18 AMS measurements; 173 individual shells) recovered from late-Pleistocene sediments. The fossil shells yielded 14C ages that were statistically indistinguishable from 14C ages of well-preserved plant macrofossils from the same stratum. Although just one site, these results suggest that small terrestrial gastropod shells may behave as closed systems with respect to carbon over geologic

  13. Disparity and convergence: Chinese provincial government health expenditures.

    PubMed

    Pan, Jay; Wang, Peng; Qin, Xuezheng; Zhang, Shufang

    2013-01-01

    The huge regional disparity in government health expenditures (GHE) is a major policy concern in China. This paper addresses whether provincial GHE converges in China from 1997 to 2009 using the economic convergence framework based on neoclassical economic growth theory. Our empirical investigation provides compelling evidence of long-term convergence in provincial GHE within China, but not in short-term. Policy implications of these empirical results are discussed.

  14. Disparity and Convergence: Chinese Provincial Government Health Expenditures

    PubMed Central

    Pan, Jay; Wang, Peng; Qin, Xuezheng; Zhang, Shufang

    2013-01-01

    The huge regional disparity in government health expenditures (GHE) is a major policy concern in China. This paper addresses whether provincial GHE converges in China from 1997 to 2009 using the economic convergence framework based on neoclassical economic growth theory. Our empirical investigation provides compelling evidence of long-term convergence in provincial GHE within China, but not in short-term. Policy implications of these empirical results are discussed. PMID:23977049

  15. Ethnic and Racial Disparities in Education: Psychology's Role in Understanding and Reducing Disparities

    ERIC Educational Resources Information Center

    Quintana, Stephen M.; Mahgoub, Lana

    2016-01-01

    We review the scope and sources of ethnic and racial disparities in education with a focus on the the implications of psychological theory and research for understanding and redressing these disparities. We identify 3 sources of ethnic and racial disparities including (a) social class differences, (b) differential treatment based on ethnic and…

  16. Ethnic and Racial Disparities in Education: Psychology's Role in Understanding and Reducing Disparities

    ERIC Educational Resources Information Center

    Quintana, Stephen M.; Mahgoub, Lana

    2016-01-01

    We review the scope and sources of ethnic and racial disparities in education with a focus on the the implications of psychological theory and research for understanding and redressing these disparities. We identify 3 sources of ethnic and racial disparities including (a) social class differences, (b) differential treatment based on ethnic and…

  17. The absolute age of events in Earth and human history on the basis of radiocarbon dating

    NASA Astrophysics Data System (ADS)

    Pazdur, Anna

    2011-01-01

    Radiocarbon chronometry holds a special place among the many discoveries made in the field of applied nuclear research. Few discoveries in fact, even among those being honored with the Nobel Prize, have had such a powerful and lasting impact on the further development of science. This method, as well as many other complex research methods, which appear to constitute an independent scientific discipline, arose as a result of many years of work by a team of several scientists. However, the actual founder of radiocarbon chronometry was one man, Willard Frank Libby, honored for his contribution with the Nobel Prize in Chemistry in 1960. In Poland, the creative activity in this area was begun in the late 1940s by Włodzimierz Mościcki, who continued it in the last 10 years of his life in the Silesian University of Technology in Gliwice, where he founded the Gliwice Radiocarbon Laboratory.

  18. A graphical method to evaluate predominant geochemical processes occurring in groundwater systems for radiocarbon dating

    USGS Publications Warehouse

    Han, Liang-Feng; Plummer, L. Niel; Aggarwal, Pradeep

    2012-01-01

    A graphical method is described for identifying geochemical reactions needed in the interpretation of radiocarbon age in groundwater systems. Graphs are constructed by plotting the measured 14C, δ13C, and concentration of dissolved inorganic carbon and are interpreted according to specific criteria to recognize water samples that are consistent with a wide range of processes, including geochemical reactions, carbon isotopic exchange, 14C decay, and mixing of waters. The graphs are used to provide a qualitative estimate of radiocarbon age, to deduce the hydrochemical complexity of a groundwater system, and to compare samples from different groundwater systems. Graphs of chemical and isotopic data from a series of previously-published groundwater studies are used to demonstrate the utility of the approach. Ultimately, the information derived from the graphs is used to improve geochemical models for adjustment of radiocarbon ages in groundwater systems.

  19. Youngest radiocarbon age for Jefferson's ground sloth, Megalonyx jeffersonii (Xenarthra, Megalonychidae)

    NASA Astrophysics Data System (ADS)

    Gregory McDonald, H.; Stafford, Thomas W.; Gnidovec, Dale M.

    2015-03-01

    A partial skeleton of the extinct ground sloth, Megalonyx jeffersonii, recovered from a farm near Millersburg, Ohio in 1890, was radiocarbon dated for the first time. The ungual dated is part of a skeleton mounted for exhibit at the Orton Geological Museum at Ohio State University and was the first mounted skeleton of this animal. From its initial discovery the bones were treated with multiple organic compounds that had the potential to compromise the radiocarbon age and the specimen required special treatments in order to obtain a valid radiocarbon age. The 14C measurement on the ungual from this skeleton (11,235 ± 40 14C yr BP = 13,180-13,034 cal yr BP) is the youngest 14C age presently determined for M. jeffersonii.

  20. The impact of age at death on the lag time of radiocarbon values in human bone.

    PubMed

    Ubelaker, Douglas H; Thomas, Christian; Olson, Jacqueline E

    2015-06-01

    Analysis of modern bomb-pulse radiocarbon in human bone offers data needed to interpret the post-mortem interval in skeletonized human remains recovered from forensic contexts. Radiocarbon analysis of different tissues with distinct rates of remodeling allows proper placement of the values on the modern bomb-curve. However, the lag time between the date of intercept on the curve and the actual death date is largely affected by the age at death. Published data on radiocarbon analysis of individuals of known age at death and death dates indicate that this lag time increases with age until about 60 years. The lag time documented for each decade of life can be used to compensate for this age-related factor and increase the accuracy of interpretation of the death date. While this method could be greatly improved by original research with a larger sample size, this study provides an adequate point from which to launch further investigations into the subject.

  1. Microflora distributions in paleosols: a method for calculating the validity of radiocarbon-dated surfaces

    SciTech Connect

    Mahaney, W.C.; Boyer, M.G.

    1986-08-01

    Microflora (bacteria and fungi) distributions in several paleosols from Mount Kenya, East Africa, provide important information about contamination of buried soil horizons dated by radiocarbon. High counts of bacteria and fungi in buried soils provide evidence for contamination by plant root effects or ground water movement. Profiles with decreasing counts versus depth appear to produce internally consistent and accurate radiocarbon dates. Profiles with disjunct or bimodal distributions of microflora at various depths produce internally inconsistent chronological sequences of radiocarbon-dated buried surfaces. Preliminary results suggest that numbers up to 5 x 10/sup 2/ g/sup -1/ for bacteria in buried A horizons do not appear to affect the validity of /sup 14/C dates. Beyond this threshold value, contamination appears to produce younger dates, the difference between true age and /sup 14/C age increasing with the amount of microflora contamination.

  2. Molecular gas sensing below parts per trillion: radiocarbon-dioxide optical detection.

    PubMed

    Galli, I; Bartalini, S; Borri, S; Cancio, P; Mazzotti, D; De Natale, P; Giusfredi, G

    2011-12-30

    Radiocarbon ((14)C) concentrations at a 43 parts-per-quadrillion level are measured by using saturated-absorption cavity ringdown spectroscopy by exciting radiocarbon-dioxide ((14)C(16)O(2)) molecules at the 4.5 μm wavelength. The ultimate sensitivity limits of molecular trace gas sensing are pushed down to attobar pressures using a comb-assisted absorption spectroscopy setup. Such a result represents the lowest pressure ever detected for a gas of simple molecules. The unique sensitivity, the wide dynamic range, the compactness, and the relatively low cost of this table-top setup open new perspectives for ^{14}C-tracing applications, such as radiocarbon dating, biomedicine, or environmental and earth sciences. The detection of other very rare molecules can be pursued as well thanks to the wide and continuous mid-IR spectral coverage of the described setup.

  3. Black Carbon in Marine Dissolved Organic Carbon: Abundance and Radiocarbon Measurements in the Global Ocean

    NASA Astrophysics Data System (ADS)

    Coppola, A. I.; Walker, B. D.; Druffel, E. R. M.

    2014-12-01

    Compound specific radiocarbon analysis is a powerful tool for understanding the cycling of individual components, such as black carbon (BC) produced from biomass burning and fossil fuel combustion, within bulk pools, like the marine dissolved organic carbon pool. Here, we use a solid phase extraction method and a wide range of solvent polarities to concentrate dissolved organic carbon from seawater. Then we isolate BC in sufficient quantities for radiocarbon analysis. We report the radiocarbon age of BC, concentrations and its relative structure, from coastal and open ocean surface samples. We will discuss our progress towards measuring these quantities in dissolved organic carbon collected from the Pacific and Atlantic oceans to understand the fate, transformation and cycling of BC in the world ocean. These measurements are paired with bulk DOC Δ14C profiles, providing insight into the role of BC as a missing sink in the ultra-refractory DOC pool.

  4. Combined dendrochronological and radiocarbon dating of six Russian icons from the 15th-17th centuries

    NASA Astrophysics Data System (ADS)

    Dolgikh, A. V.; Matskovsky, V. V.; Voronin, K. V.; Solomina, O. N.

    2017-06-01

    The results of dendrochronological and radiocarbon dating by means of accelerator mass spectrometry (AMS) of six medieval icons, originating from northern European Russia and painted on wooden panels made from Scots pine, dated to the 15th to 17th centuries are presented. The panels of each icon were studied using dendrochronology. Five to six AMS dates were obtained for four icons. Although five icons were dendro-dated successfully, one failed to be reliably cross-dated with the existing master tree-ring chronologies and it was dated by radiocarbon wiggle-matching. Dendrochronological dating and wiggle-matching of radiocarbon dates allowed us to determine the narrow chronological intervals of icon creation.

  5. Rural/Urban Disparities in Science Achievement in Post-Socialist Countries: The Evolving Influence of Socioeconomic Status

    ERIC Educational Resources Information Center

    Kryst, Erica L.; Kotok, Stephen; Bodovski, Katerina

    2015-01-01

    Disparities in educational outcomes exist between students in rural areas as compared to students in urban settings. While there is some evidence that these rural disparities are present in eastern Europe, little is known about young peoples' lives in the rural areas of this region. This paper presents an analysis of science achievement by…

  6. High-resolution deep Northeast Pacific radiocarbon record shows little change in ventilation rate during the last deglaciation

    NASA Astrophysics Data System (ADS)

    Lund, D. C.; Mix, A. C.

    2010-12-01

    The rise in atmospheric carbon dioxide during the last deglaciation is thought to be driven by release of carbon sequestered in the abyssal ocean. This mechanism requires a poorly ventilated deep Pacific during the Last Glacial Maximum (LGM) and enhanced ventilation during the deglaciation. Here we evaluate the plausibility of this scenario using planktonic and benthic foraminiferal radiocarbon data from a high-sedimentation rate core (~25 cm/kyr) collected in the deep (2700 m) Northeast Pacific. We estimate that the mean benthic-planktonic (B-P) age was 1620±190 years during the LGM (n=10 pairs). This value is indistinguishable from the mean B-P difference for the deglaciation (1500±230; n=20 pairs) and the difference between surface and deep water 14C ages today (1560±70 years). Furthermore, our time series of benthic Δ14C parallels atmospheric Δ14C with an offset of 300±50‰ from 22 to 10 kyr BP. These data suggest the ventilation rate of the deep NE Pacific remained nearly constant during the deglaciation, consistent with lower resolution data from this region (Okazaki et al., 2010). Between 22 and 16 kyr BP, Δ14C in the deep NE Pacific varied between 0 and 100‰, well above the -200‰ values estimated at intermediate depths off of Baja California during the Mystery Interval (Marchitto et al., 2007). The deep NE Pacific apparently did not contain water of adequate age to source deglacial Δ14C anomalies shallower in the water column. Given that Antarctic Intermediate Water is also an unlikely source (de Pol-Holz et al., 2010; Rose et al., 2010), an alternative explanation is necessary for the extreme 14C depletions in the eastern tropical Pacific. De Pol-Holz, R. D., et al. 2010. No signature of abyssal carbon in intermediate waters off Chile during deglaciation. Nature Geoscience 3, 192-195. Marchitto, T., Lehman, S., Ortiz, J., Fluckiger, J. & van Geen, A. 2007. Marine radiocarbon evidence for the mechanism of deglacial atmospheric CO2 rise. Science

  7. Age estimation in forensic sciences: Application of combined aspartic acid racemization and radiocarbon analysis

    SciTech Connect

    Alkass, K; Buchholz, B A; Ohtani, S; Yamamoto, T; Druid, H; Spalding, S L

    2009-11-02

    Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster, since the age at death, birth date and year of death, as well as gender, can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization has shown reproducible and more precise results. In this paper we analyze teeth from Swedish individuals using both aspartic acid racemization and radiocarbon methodologies. The rationale behind using radiocarbon analysis is that above-ground testing of nuclear weapons during the cold war (1955-1963) caused an extreme increase in global levels of carbon-14 ({sup 14}C) which have been carefully recorded over time. Forty-four teeth from 41 individuals were analyzed using aspartic acid racemization analysis of tooth crown dentin or radiocarbon analysis of enamel and ten of these were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods correlated well (R2=0.66, p < 0.05). Radiocarbon analysis showed an excellent precision with an overall absolute error of 0.6 {+-} 04 years. Aspartic acid racemization also showed a good precision with an overall absolute error of 5.4 {+-} 4.2 years. Whereas radiocarbon analysis gives an estimated year of birth, racemization analysis indicates the chronological age of the individual at the time of death. We show how these methods in combination can also assist in the estimation of date of death of an unidentified victim. This strategy can be of significant assistance in forensic casework involving dead victim identification.

  8. Constraining the Stratosphere-Troposphere Exchange of Radiocarbon using AirCore 14CO2 Measurements

    NASA Astrophysics Data System (ADS)

    Chen, H.

    2016-12-01

    Radiocarbon (14C) plays an important role in the carbon cycle studies to understand both natural and anthropogenic carbon fluxes, but also in atmospheric chemistry to constrain hydroxyl radical (OH) concentrations in the atmosphere. Apart from the enormous 14C emissions from nuclear bomb testing in the 1950s and 1960s, radiocarbon is primarily produced in the upper atmosphere due to reactions of nitrogen nuclei with thermal neutrons that are induced by cosmic rays. 14C is quickly oxidized to 14CO, which is then further oxidized to 14CO2 by OH. To this end, better understanding the radiocarbon source is very useful to advance the use of radiocarbon for these applications. However, upper atmospheric 14C observations have been very sparse to constrain the magnitude and the location of the 14C production as well as the transport of radiocarbon from the stratosphere to the troposphere. Recently we have successfully made stratospheric 14CO2 measurements using AirCore samples from Sodankylä, Northern Finland, along with regular AirCore profiles of CO2, CH4, and CO since 2013. In this study, we calculate the stratosphere-troposphere exchange of 14C using the correlation between 14CO2 and N2O, and the estimated N2O loss rate. Besides this, we assess the impact of the mean age of air on 14CO2 profiles. Furthermore, we will evaluate the influence of different cosmogenic 14C production scenarios and the uncertainties in the OH field on the seasonal cycles of radiocarbon and on the stratosphere-troposphere exchange.

  9. Age estimation in forensic sciences: application of combined aspartic acid racemization and radiocarbon analysis.

    PubMed

    Alkass, Kanar; Buchholz, Bruce A; Ohtani, Susumu; Yamamoto, Toshiharu; Druid, Henrik; Spalding, Kirsty L

    2010-05-01

    Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster because the age at death, birth date, and year of death as well as gender can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization, has shown reproducible and more precise results. In this study, we analyzed teeth from Swedish individuals using both aspartic acid racemization and radiocarbon methodologies. The rationale behind using radiocarbon analysis is that aboveground testing of nuclear weapons during the cold war (1955-1963) caused an extreme increase in global levels of carbon-14 ((14)C), which has been carefully recorded over time. Forty-four teeth from 41 individuals were analyzed using aspartic acid racemization analysis of tooth crown dentin or radiocarbon analysis of enamel, and 10 of these were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods correlated well (R(2) = 0.66, p < 0.05). Radiocarbon analysis showed an excellent precision with an overall absolute error of 1.0 +/- 0.6 years. Aspartic acid racemization also showed a good precision with an overall absolute error of 5.4 +/- 4.2 years. Whereas radiocarbon analysis gives an estimated year of birth, racemization analysis indicates the chronological age of the individual at the time of death. We show how these methods in combination can also assist in the estimation of date of death of an unidentified victim. This strategy can be of significant assistance in forensic casework involving dead victim identification.

  10. Analysis of artificial radiocarbon in different skeletal and dental tissue types to evaluate date of death.

    PubMed

    Ubelaker, Douglas H; Buchholz, Bruce A; Stewart, John E B

    2006-05-01

    Radiocarbon dating, with special reference to the modern bomb-curve, can provide useful information to elucidate the date of death of skeletonized human remains. Interpretation can be enhanced with analysis of different types of tissues within a single skeleton because of the known variability of formation times and remodeling rates. Analysis of radiocarbon content of teeth, especially the enamel in tooth crowns, provides information about the date of formation in the childhood years and in consideration of the known timing of tooth formation can be used to estimate the birth date after 1950 ad. Radiocarbon analysis of modern cortical and trabecular bone samples from the same skeleton may allow proper placement on the pre-1963 or post-1963 sides of the bomb-curve as most trabecular bone generally undergoes more rapid remodeling than does most cortical bone. Pre-1963 bone formation would produce higher radiocarbon values for most trabecular bone than for most cortical bone. This relationship is reversed for formation after 1963. Radiocarbon analysis was conducted in this study on dental, cortical, and trabecular bone samples from two adult individuals of known birth (1925 and 1926) and death dates (1995 and 1959). As expected, the dental results correspond to prebomb-curve values reflecting conditions during the childhoods of the individuals. The radiocarbon content of most bone samples reflected the higher modern bomb-curve values. Within the bone sample analyses, the values of the trabecular bone were higher than those of cortical bone and supported the known placement on the pre-1963 side of the bomb-curve.

  11. Analysis of Artificial Radiocarbon in Different Skeletal and Dental Tissue Types to Evaluate Date of Death

    SciTech Connect

    Ubelaker, D H; Buchholz, B A; Stewart, J

    2005-07-19

    Radiocarbon dating, with special reference to the modern bomb-curve, can provide useful information to elucidate the date of death of skeletonized human remains. Interpretation can be enhanced with analysis of different types of tissues within a single skeleton because of the known variability of formation times and remodeling rates. Analysis of radiocarbon content of teeth, especially the enamel in tooth crowns provides information about the date of formation in the childhood years and in consideration of the known timing of tooth formation can be used to estimate the birth date after 1950 A.D. Radiocarbon analysis of modern cortical and trabecular bone samples from the same skeleton may allow proper placement on the pre-1963 or post-1963 sides of the bomb-curve since most trabecular bone generally undergoes more rapid remodeling than does most cortical bone. Pre-1963 bone formation would produce higher radiocarbon values for most trabecular bone than for most cortical bone. This relationship is reversed for formation after 1963. Radiocarbon analysis was conducted in this study on dental, cortical and trabecular bone samples from two adult individuals of known birth (1925 and 1926) and death dates (1995 and 1959). As expected, the dental results correspond to pre-bomb bomb-curve values reflecting conditions during the childhoods of the individuals. The curve radiocarbon content of most bone samples reflected the higher modern bomb-curve values. Within the bone sample analyses, the values of the trabecular bone were higher than those of cortical bone and supported the known placement on the pre-1963 side of the bomb-curve.

  12. Cation-ratio and accelerator radiocarbon dating of rock varnish on Mojave artifacts and landforms

    USGS Publications Warehouse

    Dorn, R.I.; Bamforth, D.B.; Cahill, T.A.; Dohrenwend, J.C.; Turrin, B.D.; Donahue, D.J.; Jull, A.J.T.; Long, A.; Macko, M.E.; Weil, E.B.; Whitley, D.S.; Zabel, T.H.

    1986-01-01

    The first accelerator radiocarbon dates of rock varnishes are reported along with potassium/argon ages of lava flows and conventional radiocarbon dates of pluvial lake shorelines, in an empirical calibration of rock varnish K + + Ca2+/Ti4+ ratios with age in the Mojave Desert, eastern California. This calibration was used to determine the cation-ratio dates of 167 artifacts. Although cation-ratio dating is an experimental method, some dates suggest human occupation of the Mojave Desert in the late Pleistocene.

  13. Simultaneous measurement of tritium and radiocarbon by ultra-low-background proportional counting

    DOE PAGES

    Mace, Emily; Aalseth, Craig; Alexander, Tom; ...

    2016-12-21

    Use of ultra-low-background capabilities at Pacific Northwest National Laboratory provide enhanced sensitivity for measurement of low-activity sources of tritium and radiocarbon using proportional counters. Tritium levels are nearly back to pre-nuclear test backgrounds (~2-8 TU in rainwater), which can complicate their dual measurement with radiocarbon due to overlap in the beta decay spectra. In this paper, we present results of single-isotope proportional counter measurements used to analyze a dual-isotope methane sample synthesized from ~120 mg of H2O and present sensitivity results.

  14. Radiocarbon dating of extinct fauna in the Americas recovered from tar pits

    NASA Astrophysics Data System (ADS)

    Jull, A. J. T.; Iturralde-Vinent, M.; O'Malley, J. M.; MacPhee, R. D. E.; McDonald, H. G.; Martin, P. S.; Moody, J.; Rincón, A.

    2004-08-01

    We have obtained radiocarbon dates by accelerator mass spectrometry on bones of extinct large mammals from tar pits. Results on some samples of Glyptodon and Holmesina (extinct large mammals similar to armadillos) yielded ages of >25 and >21 ka, respectively. We also studied the radiocarbon ages of three different samples of bones from the extinct Cuban ground sloth, Parocnus bownii, which yielded dates ranging from 4960 ± 280 to 11 880 ± 420 yr BP. In order to remove the tar component pretreat the samples sufficiently to obtain reliable dates, we cleaned the samples by Soxhlet extraction in benzene. Resulting samples of collagenous material were often small.

  15. Cation-ratio and accelerator radiocarbon dating of rock varnish on mojave artifacts and landforms.

    PubMed

    Dorn, R I; Bamforth, D B; Cahill, T A; Dohrenwend, J C; Turrin, B D; Donahue, D J; Jull, A J; Long, A; Macko, M E; Weil, E B; Whitley, D S; Zabel, T H

    1986-02-21

    The first accelerator radiocarbon dates of rock varnishes are reported along with potassium/argon ages of lava flows and conventional radiocarbon dates of pluvial lake shorelines, in an empirical calibration of rock varnish K(+) + Ca(2+)/Ti(4+) ratios with age in the Mojave Desert, eastern California. This calibration was used to determine the cation-ratio dates of 167 artifacts. Although cation-ratio dating is an experimental method, some dates suggest human occupation of the Mojave Desert in the late Pleistocene.

  16. [Radiocarbon dating of pollen and spores in wedge ice from Iamal and Kolyma].

    PubMed

    Vasil'chuk, A K

    2004-01-01

    Radiocarbon dating of pollen concentrate from late Pleistocene syngenetic wedge ice was carried out using acceleration mass spectrometry (AMS) in Seyakha and Bizon sections. Comparison of the obtained dating with palynological analysis and AMS radiocarbon dating previously obtained for other organic fractions of the same samples allowed us to evaluate accuracy of dating of different fractions. Quantitative tests for data evaluation were considered in terms of possible autochthonous or allochthonous accumulation of the material on the basis of pre-Pleistocene pollen content in these samples. Paleoecological information content of pollen spectra from late Pleistocene syngenetic wedge ice was evaluated.

  17. Cation-ratio and accelerator radiocarbon dating of rock varnish on Mojave artifacts and landforms

    SciTech Connect

    Dorn, R.I.; Bamforth, D.B.; Cahill, T.A.; Dohrenwend, J.C.; Turrin, B.D.; Donahue, D.J.; Jull, A.J.T.; Long, A.; Macko, M.E.; Weil, E.B.; Whitley, D.S.

    1986-02-21

    The first accelerator radiocarbon dates of rock varnishes are reported along with potassium/argon ages of lava flows and conventional radiocarbon dates of pluvial lake shorelines, in an empirical calibration of rock varnish K/sup +/ + Ca/sup 2 +//Ti/sup 4 +/ ratios with age in the Mojave Desert, eastern California. This calibration was used to determine the cation-ratio dates of 167 artifacts. Although cation-ratio dating is an experimental method, some dates suggest human occupation of the Mojave Desert in the late Pleistocene. 25 references, 2 figures, 2 tables.

  18. Radiocarbon analysis of the Torah scrolls from the National Museum of Brazil collection

    NASA Astrophysics Data System (ADS)

    Oliveira, Fabiana M.; Araujo, Carlos A. R.; Macario, Kita D.; Cid, Alberto S.

    2015-10-01

    This radiocarbon study aims to physically verify the critical analysis of the Torah scrolls from the National Museum of Brazil collection. Although the manuscript was formerly believed to be as old as the 10th century, the paleographic and stylistic study of the books of Genesis and Deuteronomy revealed features that could be associated to the year 1560 AD. Radiocarbon analysis was performed and a phase model limited by a Historical boundary was applied. The results are in agreement with the critical analysis of the manuscript that it is not older than the 16th century.

  19. Simultaneous measurement of tritium and radiocarbon by ultra-low-background proportional counting

    SciTech Connect

    Mace, Emily; Aalseth, Craig; Alexander, Tom; Back, Henning; Day, Anthony; Hoppe, Eric; Keillor, Martin; Moran, Jim; Overman, Cory; Panisko, Mark; Seifert, Allen

    2016-12-21

    Use of ultra-low-background capabilities at Pacific Northwest National Laboratory provide enhanced sensitivity for measurement of low-activity sources of tritium and radiocarbon using proportional counters. Tritium levels are nearly back to pre-nuclear test backgrounds (~2-8 TU in rainwater), which can complicate their dual measurement with radiocarbon due to overlap in the beta decay spectra. In this paper, we present results of single-isotope proportional counter measurements used to analyze a dual-isotope methane sample synthesized from ~120 mg of H2O and present sensitivity results.

  20. Radiocarbon Content of Intermediate Waters off West Sumatra During the Last 45,000 Years

    NASA Astrophysics Data System (ADS)

    De Pol-Holz, R.; Mohtadi, M.; Southon, J. R.

    2014-12-01

    Radiocarbon content of intermediate waters originating from the Southern Ocean is held as a likely smoking gun of the events that triggered the atmospheric CO2 rise and its radiocarbon decline during the last glacial-interglacial transition. Late Glacial depleted radiocarbon water masses have been found at intermediate depths off the coast of Baja California, the Galapagos, the Arabian Sea, but not unequivocally elsewhere. Knowing the route of the old water is therefore central for the required mechanistic linkage of Southern Ocean processes and the atmospheric response. A common approach to search for the old water reservoir is the radiocarbon difference between planktonic and benthic foraminifera or 'apparent ventilation age'. Caveats of this approach are due to the fact that it relies strongly on the knowledge of the surface water reservoir age. In this study, we present a high-resolution radiocarbon difference between surface and intermediate depth waters off west Sumatra in the attempt to elucidate a possible route of the old water from its hypothetical source in the high latitudes near Antarctica on its way to the lower latitude sites where it has been observed. Samples come from core SO189-39KL (0°47'S, 99°55'E, 517 m), a 1350 cm hemipelagic sedimentary sequence that spans the last 45,000 years. Radiocarbon determinations were made at centennial time resolution on both planktonic and benthic species. Calibration of the planktonic radiocarbon as age control points allowed us to infer the Δ14C of the intermediate waters. Our results show that throughout the LGM and the entire deglaciation, radiocarbon content of intermediate depths in the area remained with an almost constant age difference with the contemporaneous atmosphere. Unless we have grossly underestimated the local planktonic reservoir age, our results discard this area as a probable route for the spreading of the old water along its way to northern latitudes. In light of recent evidence from the

  1. RADIOCARBON MEASUREMENT OF THE BIOGENIC CONTRIBUTION TO SUMMERTIME PM 2.5 AMBIENT AEROSOL IN NASHVILLE, TN

    EPA Science Inventory

    Radiocarbon (14C) measurements performed on PM-2.5 samples collected near Nashville, TN from June 21 to July 13, 1999, showed high levels of modern carbon, ranging from 56 to 80% of the total carbon in the samples. Radiocarbon measurements performed on dichloromethane extracts of...

  2. Radiocarbon content in the annual tree rings during last 150 years and time variation of cosmic rays

    NASA Technical Reports Server (NTRS)

    Kocharov, G. E.; Metskvarishvili, R. Y.; Tsereteli, S. L.

    1985-01-01

    The results of the high accuracy measurements of radiocarbon abundance in precisely dated tree rings in the interval 1800 to 1950 yrs are discussed. Radiocarbon content caused by solar activity is established. The temporal dependence of cosmic rays is constructed, by use of radio abundance data.

  3. Racial Disparity in Minnesota's Child Protection System

    ERIC Educational Resources Information Center

    Johnson, Erik P.; Clark, Sonja; Donald, Matthew; Pedersen, Rachel; Pichotta, Catherine

    2007-01-01

    Minnesota has been recognized by several studies as a state with a significant amount of racial disparity in its child protection system. This study, using 2001 data from Minnesota's Social Services Information Service, was conducted to determine at which of the six decision points in Minnesota's child welfare system racial disparities are…

  4. Health disparities and the cancer survivor.

    PubMed

    Blinder, Victoria S; Griggs, Jennifer J

    2013-12-01

    Disparities on the basis of race and ethnicity have been described in a variety of survivorship outcomes, including late and long-term effects of treatment, surveillance and health maintenance, and psychosocial outcomes. However, the current body of literature is limited in scope and additional research is needed to better define and address disparities among cancer survivors. © 2013 Elsevier Inc. All rights reserved.

  5. Health Disparities and Gaps in School Readiness

    ERIC Educational Resources Information Center

    Currie, Janet

    2005-01-01

    The author documents pervasive racial disparities in the health of American children and analyzes how and how much those disparities contribute to racial gaps in school readiness. She explores a broad sample of health problems common to U.S. children, such as attention deficit hyperactivity disorder, asthma, and lead poisoning, as well as maternal…

  6. Addressing Asthma Health Disparities: A Multilevel Challenge

    PubMed Central

    Canino, Glorisa; McQuaid, Elizabeth L.; Rand, Cynthia S.

    2009-01-01

    Substantial research has documented pervasive disparities in the prevalence, severity, and morbidity of asthma among minority populations compared to non-Latino whites. The underlying causes of these disparities are not well understood, and as a result, the leverage points to address them remain unclear. A multilevel framework for integrating research in asthma health disparities is proposed in order to advance both future research and clinical practice. The components of the proposed model include health care policies and regulations, operation of the health care system, provider/clinician-level factors, social/environmental factors, and individual/family attitudes and behaviors. The body of research suggests that asthma disparities have multiple, complex and inter-related sources. Disparities occur when individual, environmental, health system, and provider factors interact with one another over time. Given that the causes of asthma disparities are complex and multilevel, clinical strategies to address these disparities must therefore be comparably multilevel and target many aspects of asthma care. Clinical Implications: Several strategies that could be applied in clinical settings to reduce asthma disparities are described including the need for routine assessment of the patient’s beliefs, financial barriers to disease management, and health literacy, and the provision of cultural competence training and communication skills to health care provider groups. PMID:19447484

  7. What limits the morphological disparity of clades?

    PubMed

    Oyston, Jack W; Hughes, Martin; Wagner, Peter J; Gerber, Sylvain; Wills, Matthew A

    2015-12-06

    The morphological disparity of species within major clades shows a variety of trajectory patterns through evolutionary time. However, there is a significant tendency for groups to reach their maximum disparity relatively early in their histories, even while their species richness or diversity is comparatively low. This pattern of early high-disparity suggests that there are internal constraints (e.g. developmental pleiotropy) or external restrictions (e.g. ecological competition) upon the variety of morphologies that can subsequently evolve. It has also been demonstrated that the rate of evolution of new character states decreases in most clades through time (character saturation), as does the rate of origination of novel bodyplans and higher taxa. Here, we tested whether there was a simple relationship between the level or rate of character state exhaustion and the shape of a clade's disparity profile: specifically, its centre of gravity (CG). In a sample of 93 extinct major clades, most showed some degree of exhaustion, but all continued to evolve new states up until their extinction. Projection of states/steps curves suggested that clades realized an average of 60% of their inferred maximum numbers of states. Despite a weak but significant correlation between overall levels of homoplasy and the CG of clade disparity profiles, there were no significant relationships between any of our indices of exhaustion curve shape and the clade disparity CG. Clades showing early high-disparity were no more likely to have early character saturation than those with maximum disparity late in their evolution.

  8. What limits the morphological disparity of clades?

    PubMed Central

    Oyston, Jack W.; Hughes, Martin; Wagner, Peter J.; Gerber, Sylvain; Wills, Matthew A.

    2015-01-01

    The morphological disparity of species within major clades shows a variety of trajectory patterns through evolutionary time. However, there is a significant tendency for groups to reach their maximum disparity relatively early in their histories, even while their species richness or diversity is comparatively low. This pattern of early high-disparity suggests that there are internal constraints (e.g. developmental pleiotropy) or external restrictions (e.g. ecological competition) upon the variety of morphologies that can subsequently evolve. It has also been demonstrated that the rate of evolution of new character states decreases in most clades through time (character saturation), as does the rate of origination of novel bodyplans and higher taxa. Here, we tested whether there was a simple relationship between the level or rate of character state exhaustion and the shape of a clade's disparity profile: specifically, its centre of gravity (CG). In a sample of 93 extinct major clades, most showed some degree of exhaustion, but all continued to evolve new states up until their extinction. Projection of states/steps curves suggested that clades realized an average of 60% of their inferred maximum numbers of states. Despite a weak but significant correlation between overall levels of homoplasy and the CG of clade disparity profiles, there were no significant relationships between any of our indices of exhaustion curve shape and the clade disparity CG. Clades showing early high-disparity were no more likely to have early character saturation than those with maximum disparity late in their evolution. PMID:26640649

  9. Racial Disparity in Minnesota's Child Protection System

    ERIC Educational Resources Information Center

    Johnson, Erik P.; Clark, Sonja; Donald, Matthew; Pedersen, Rachel; Pichotta, Catherine

    2007-01-01

    Minnesota has been recognized by several studies as a state with a significant amount of racial disparity in its child protection system. This study, using 2001 data from Minnesota's Social Services Information Service, was conducted to determine at which of the six decision points in Minnesota's child welfare system racial disparities are…

  10. Why the WTA - WTP disparity matters

    Treesearch

    Brown Thomas C.; Gregory R.

    1999-01-01

    The disparity between willingness to pay (WTP) and willingness to accept compensation (WTA) has been demonstrated repeatedly. Because using WTP estimates of value where a WTA estimate is appropriate tends to undervalue environmental assets, this issue is important to environmental managers. We summarize reasons for the disparity and then discuss some of the...

  11. MOTIVATIONAL STRUCTURE AND PERCEIVED ROLE DISPARITIES.

    ERIC Educational Resources Information Center

    BENNETT, WILLIAM S., JR.

    THE RELATIONSHIP BETWEEN THE CLASSES OF COGNITIVE PHENOMENA WAS INVESTIGATED, I.E., THE MOTIVATIONAL STRUCTURE AND THE DEGREE OF PERCEIVED ROLE DISPARITY OF TEACHERS. ONE ELEMENT OF MOTIVATION, CALLED "ORIENTATION FOR CHANGE," WAS RELATED TO DIFFERENT TYPES OF ROLE DISPARITY, INCLUDING "OPTIMISM" OR THE EXTENT IN WHICH THE…

  12. Role of genomics in eliminating health disparities

    PubMed Central

    Kashyap, Meghana V; Nolan, Michael; Sprouse, Marc; Chakraborty, Ranajit; Cross, Deanna; Roby, Rhonda; Vishwanatha, Jamboor K

    2015-01-01

    The Texas Center for Health Disparities, a National Institute on Minority Health and Health Disparities Center of Excellence, presents an annual conference to discuss prevention, awareness education, and ongoing research about health disparities both in Texas and among the national population. The 2014 Annual Texas Conference on Health Disparities brought together experts in research, patient care, and community outreach on the “Role of Genomics in Eliminating Health Disparities.” Rapid advances in genomics and pharmacogenomics are leading the field of medicine to use genetics and genetic risk to build personalized or individualized medicine strategies. We are at a critical juncture of ensuring such rapid advances benefit diverse populations. Relatively few forums have been organized around the theme of the role of genomics in eliminating health disparities. The conference consisted of three sessions addressing “Gene-Environment Interactions and Health Disparities,” “Personalized Medicine and Elimination of Health Disparities,” and “Ethics and Public Policy in the Genomic Era.” This article summarizes the basic science, clinical correlates, and public health data presented by the speakers. PMID:26435701

  13. Database of Alluvial Radiocarbon Dates in European Russia and Siberia and its Palaeohydrological Interpretation

    NASA Astrophysics Data System (ADS)

    Matlakhova, Ekaterina; Panin, Andrei

    2017-04-01

    We collected and analyzed published radiocarbon dates from East European Plain (EEP) and Siberia to pick absolute dates on alluvial and associated deposits. After filtering unreliable dates, 1000 radiocarbon dates from EEP and 500 from Siberia were included into the database. Each date was supplied with information on geographic location and coordinates, catchment area, geomorphological position, characteristics of geological section and dated materials. Also the information about published sources was given. Documented sections refer to fluvial forms in a wide range of catchment sizes. To extract palaeohydrological signal we used two kinds of proxies: sedimentological and geomorphological. We used the following indicators of low activity: organic horizons (soil, peat) in overbank alluvium, balka bottoms and gully fans, small river palaeochannels; and the following indicators of high activity: active sedimentation on river floodplains (burial of organic horizons), balka bottoms and gully fans, erosion by flood flows on floodplains, in bottoms of balkas and gullies, river incision, big palaeochannels, channel avulsions and chute cutoffs. 
 Each date that received palaeohydrological interpretation was regarded as the indicator of a particular Local Palaeohydrological Event. Combined probability density functions of high- and low-activity dates were used to detect time intervals of different palaeohydrological status. For EEP after low fluvial activity during LGM two palaeohydrological epochs were designated: extremely high activity in the end of MIS 2 (ca. 18-11.7 ka b2k), and much lower activity in the Holocene. Within the Holocene two hierarchical levels of hydroclimatic variability were designated according to their duration and magnitude - regional palaeohydrological phases (centuries to few millennia) and regional palaeofluvial episodes (decades to few centuries). Tendency is rather clear of activity lowering in the first half and rise in the second half of

  14. Quantifying Access Disparities in Response Plans

    PubMed Central

    Indrakanti, Saratchandra; Mikler, Armin R.; O’Neill, Martin; Tiwari, Chetan

    2016-01-01

    Effective response planning and preparedness are critical to the health and well-being of communities in the face of biological emergencies. Response plans involving mass prophylaxis may seem feasible when considering the choice of dispensing points within a region, overall population density, and estimated traffic demands. However, the plan may fail to serve particular vulnerable subpopulations, resulting in access disparities during emergency response. For a response plan to be effective, sufficient mitigation resources must be made accessible to target populations within short, federally-mandated time frames. A major challenge in response plan design is to establish a balance between the allocation of available resources and the provision of equal access to PODs for all individuals in a given geographic region. Limitations on the availability, granularity, and currency of data to identify vulnerable populations further complicate the planning process. To address these challenges and limitations, data driven methods to quantify vulnerabilities in the context of response plans have been developed and are explored in this article. PMID:26771551

  15. Racial Disparity in Police Contacts

    PubMed Central

    Crutchfield, Robert D.; Haggerty, Kevin P.; McGlynn, Anne; Catalano, Richard F.

    2013-01-01

    Criminologists agree the race disparity in arrests cannot be fully explained by differences in criminal behavior. We examine social environment factors that may lead to racial differences in police contact in early adolescence, including family, peers, school, and community. Data are from 331 8th-grade students. Blacks were almost twice as likely as Whites to report a police contact. Blacks reported more property crime but not more violent crime than Whites. Police contacts were increased by having a parent who had been arrested, a sibling involved in criminal activity, higher observed reward for negative behavior, having school disciplinary actions, and knowing adults who engaged in substance abuse or criminal behavior. Race differences in police contacts were partially attributable to more school discipline. PMID:24363956

  16. Health Disparities and Discrimination: Three Perspectives

    PubMed Central

    Ndiaye, Khadidiatou; Krieger, Janice R.; Warren, Jennifer R.; Hecht, Michael L.; Okuyemi, Kola

    2010-01-01

    This article presents three perspectives on health discrimination and disparities, organized around different conceptualizations of the way “space” perpetuates health disparities. The first two perspectives are grounded in conceptualizing space in a physical sense by exploring the manifestation of discrimination as a problem both among and within nations. The third perspective juxtaposes geographical space with cyberspace. The internet, with its ability to blur sense of place, social demarcations, and behavior is often considered a panacea that can eliminate the health disparities. The internet, however, may not be fulfilling its promise as an equal source of health information for all and disparities related to international and rural geography remain problematic. Solutions are proposed for reducing health disparities based on The Principle of Cultural Grounding (Hecht & Krieger, 2006; Hecht & Miller-Day, in press). PMID:20694161

  17. Decadal- to interannual-scale source water variations in the Caribbean Sea recorded by Puerto Rican coral radiocarbon

    SciTech Connect

    Kilbourne, K H; Quinn, T M; Guilderson, T P; Webb, R S; Taylor, F W

    2006-12-05

    Water that forms the Florida Current, and eventually the Gulf Stream, coalesces in the Caribbean from both subtropical and equatorial sources. The equatorial sources are made up of, in part, South Atlantic water moving northward and compensating for southward flow at depth related to meridional overturning circulation. Subtropical surface water contains relatively high amounts of radiocarbon ({sup 14}C), whereas equatorial waters are influenced by the upwelling of low {sup 14}C water and have relatively low concentrations of {sup 14}C. We use a 250-year record of {Delta}{sup 14}C in a coral from southwestern Puerto Rico along with previously published coral {Delta}{sup 14}C records as tracers of subtropical and equatorial water mixing in the northern Caribbean. Data generated in this study and from other studies indicate that the influence of either of the two water masses can change considerably on interannual to interdecadal time scales. Variability due to ocean dynamics in this region is large relative to variability caused by atmospheric {sup 14}C changes, thus masking the Suess effect at this site. A mixing model produced using coral {Delta}{sup 14}C illustrates the time varying proportion of equatorial versus subtropical waters in the northern Caribbean between 1963 and 1983. The results of the model are consistent with linkages between multidecadal thermal variability in the North Atlantic and meridional overturning circulation. Ekman transport changes related to tradewind variability are proposed as a possible mechanism to explain the observed switches between relatively low and relatively high {Delta}{sup 14}C values in the coral radiocarbon records.

  18. Using natural abundance radiocarbon to trace the flux of petrocarbon to the seafloor following the Deepwater Horizon oil spill.

    PubMed

    Chanton, Jeffrey; Zhao, Tingting; Rosenheim, Brad E; Joye, Samantha; Bosman, Samantha; Brunner, Charlotte; Yeager, Kevin M; Diercks, Arne R; Hollander, David

    2015-01-20

    In 2010, the Deepwater Horizon accident released 4.6–6.0 × 10(11) grams or 4.1 to 4.6 million barrels of fossil petroleum derived carbon (petrocarbon) as oil into the Gulf of Mexico. Natural abundance radiocarbon measurements on surface sediment organic matter in a 2.4 × 10(10) m(2) deep-water region surrounding the spill site indicate the deposition of a fossil-carbon containing layer that included 1.6 to 2.6 × 10(10) grams of oil-derived carbon. This quantity represents between 0.5 to 9.1% of the released petrocarbon, with a best estimate of 3.0–4.9%. These values may be lower limit estimates of the fraction of the oil that was deposited on the seafloor because they focus on a limited mostly deep-water area of the Gulf, include a conservative estimate of thickness of the depositional layer, and use an average background or prespill radiocarbon value for sedimentary organic carbon that produces a conservative value. A similar approach using hopane tracer estimated that 4–31% of 2 million barrels of oil that stayed in the deep sea settled on the bottom. Converting that to a percentage of the total oil that entered into the environment (to which we normalized our estimate) converts this range to 1.8 to 14.4%. Although extrapolated over a larger area, our independent estimate produced similar values.

  19. Radiocarbon evidence for mid-late Holocene changes in southwest Pacific Ocean circulation

    NASA Astrophysics Data System (ADS)

    Komugabe-Dixson, Aimée. F.; Fallon, Stewart J.; Eggins, Stephen M.; Thresher, Ronald E.

    2016-07-01

    Variability in the southwest (SW) Pacific Ocean circulation is influenced by the changes in the South Pacific subtropical gyre and its western boundary current, the East Australian Current (EAC). The EAC plays a significant role in transporting warm, well-ventilated, nutrient-poor waters to more temperate higher latitudes. Recent climate changes associated with EAC intensification have led to anomalous warming in the South Tasman, with implications for marine ecosystems and environment. A clear understanding of the significance of these changes requires knowledge of past natural variability. Here we have reconstructed a 4500 year record of regional sea surface radiocarbon reservoir ages (R) and local reservoir effects (ΔR). Our results reveal the centennial-scale variability over the last 4500 years, with R ranges as large as 390 14C yr. Older R (~410 14C yr) between 1610 to 1860 A.D. in our record, corresponding to the "Little Ice Age," suggests a weaker influence of the EAC in the South Tasman. Between 4000 and 1900 cal years B.P., R and ΔR were significantly younger than the modern, with values of ~170 and -130 14C yr, respectively, indicating increased EAC transport of tropical waters into the South Tasman. We propose that the large R variability was influenced by strong and abrupt El Niño events which punctuated the muted El Niño-Southern Oscillation (ENSO) period in the mid-late Holocene and enabled increased westward flow of gyre waters into the SW Pacific. The strengthening of the EAC extension appears to have been a response to the precession-modulated ENSO-Southern Annular Mode interactions.

  20. New constraints on deglacial marine radiocarbon anomalies from a depth transect near Baja California

    NASA Astrophysics Data System (ADS)

    Lindsay, Colin M.; Lehman, Scott J.; Marchitto, Thomas M.; Carriquiry, José D.; Ortiz, Joseph D.

    2016-08-01

    Previous studies have shown that radiocarbon activities (Δ14C) in the low-latitude, middepth Pacific and Indian Oceans were anomalously low during Heinrich Stadial 1 (HS1, ~17.8-14.6 ka) and the Younger Dryas (YD, ~12.8-11.5 ka), coincident with intervals of rising atmospheric CO2 concentration and declining atmospheric Δ14C. However, a full explanation of these events remains elusive due to sparse and sometimes conflicting data. Here we present new 14C measurements on benthic and planktic foraminifera that, in combination with previously published measurements, enable us to reconstruct the Δ14C depth gradient near Baja California. Vertical profiles were similar to present during the Last Glacial Maximum and Bølling/Allerod (14.6-12.8 ka) but display a pronounced middepth (~700 m) Δ14C minimum during HS1 and the YD. The latter observation, along with a comparison to other regional reconstructions, appears to rule out intermediate waters from the north or from directly below as proximate sources of aged 14C-depleted ocean carbon during deglaciation and point instead to changes in the composition of Equatorial Pacific intermediate waters. Simple mixing constraints require Equatorial Pacific intermediate waters to be only slightly lower in Δ14C than at Baja California, in contrast with previous observations of extremely low Δ14C at Galapagos Rise. While the latter may have been influenced by localized releases of geologic (14C-dead) CO2, the smaller and more widespread deglacial Δ14C anomalies in the Arabian Sea and North Pacific seem to require a source of aged carbon in the glacial deep Southern and Pacific Oceans for which there is growing evidence.

  1. Radiocarbon and uranium isotopes in surface waters reveal enhanced hydrologic connection with permafrost thaw

    NASA Astrophysics Data System (ADS)

    Ewing, S. A.; O'Donnell, J. A.; Koch, J. C.; Paces, J. B.; Aiken, G.; Striegl, R. G.

    2016-12-01

    The residence time of ice in permafrost is an indicator of past climate history, and of the resilience and vulnerability of high-latitude ecosystems to global change. Development of geochemical indicators of ground-ice residence times in permafrost will advance understanding of permafrost formation, preservation, and thaw in response to climate warming and other disturbance. We used uranium activity ratios (234U/238U) and radiocarbon (14C) to evaluate the signal of permafrost thaw at two gaged locations (upstream and downstream) on Beaver Creek, a central Alaskan stream that flows from rocky uplands to terraces and lowlands mantled by thick, ice-rich loess permafrost (yedoma). Uranium activity ratios in surface waters provide a tracer of transit time and source (permafrost thaw water, supra- and sub-permafrost groundwater), but must be interpreted in the context of parent material and hydrology. Previous work has shown that dissolved organic carbon (DOC) from yedoma in the age range of 10-100 ky is highly labile, suggesting ongoing production in permafrost and potential carbon (C) loss upon thaw with increasing permafrost age. Uranium activity ratios were inversely correlated with DOC-14C values in streamwater at the upstream gages throughout the year, and at the downstream gage during summer, indicating aged C that co-occurs with increased nitrate-N in winter baseflow at the upstream site, but not at the downstream site. In the context of observations at a number of sites in central Alaska, these patterns suggest enhanced hydrologic connection of the downstream site in summer that may be facilitated by permafrost thaw and may result in capture of young DOC in the floodplain. In regional streams, mineral substrate dictates hydrologic connection with permafrost thaw, with enhanced mixing of source waters from supra- and sub-permafrost groundwater as thaw progresses.

  2. Radiocarbon-Based Source apportionment of Elemental Carbon Aerosols at Seoul, South Korea

    NASA Astrophysics Data System (ADS)

    Shakerian Ghahferrokhi, Farid; Ahn, Jinho; Czimczik, Claudia I.; Holden, Sandra; Park, JinSoo

    2016-04-01

    In this study, 10 samples of PM2.5 (aerosol particle with diameter less than 2.5 μm) were collected in the Northeast of Seoul (37.60o N, 127.05o E), South Korea, over 2-4 day periods in May and June of 2015 with a high volume air sampler. The samples were analyzed for their bulk carbon (TC) and nitrogen (N) elemental and stable isotope composition with EA-IRMS. Elemental carbon (EC) was quantified with the Swiss_4S protocol using a Sunset OC/EC analyzer. Both, TC and EC were analyzed for their radiocarbon (14C) content via accelerator mass spectrometry. The mass and isotopic composition of organic carbon (OC) was quantified by (isotope) mass balance. TC loads were 6.6 +/- 1.5 ug C m-3 air (ave. +/- sd; range 4.7-9.7), with a ∆14C ranging from 240 to -446 per mill and a δ13C of -25.4+/-0.3 per mill. EC was a minor fraction of TC (7.2+/-1.9% or 0.5+/-0.2 ug C m-3 air). EC was strongly depleted in 14C (∆14C = -915 to -819 per mill), with fossil sources accounting for 88+/-3% of EC (6.3+/-1.7% of TC). OC was enriched in 14C above natural levels (∆14C = -401 to 309 per mill), and thus could not be partitioned into fossil and modern sources. Local wind directions showed that air masses originated from the South, demonstrating that regional sources may be the crucial contributor to PM pollution in Seoul during that sampling period (early summer).

  3. Using radiocarbon to investigate soil respiration impacts on atmospheric CO2

    NASA Astrophysics Data System (ADS)

    Phillips, C. L.; LaFranchi, B. W.; McFarlane, K. J.; Desai, A. R.

    2013-12-01

    While soil respiration is believed to represent the largest single source of CO2 emissions on a global scale, there are few tools available to measure soil emissions at large spatial scales. We investigated whether radiocarbon (14C) abundance in CO2 could be used to detect and characterize soil emissions in the atmosphere, taking advantage of the fact that 14C abundance in soil carbon is elevated compared to the background atmosphere, a result of thermonuclear weapons testing during the mid-20th Century (i.e. bomb-C). Working in a temperate hardwood forest in Northern Wisconsin during 2011-12, we made semi-high-frequency measurements of CO2 at nested spatial scales from the soil subsurface to 150 m above ground level. These measurements were used to investigate seasonal patterns in respired C sources, and to evaluate whether variability in soil-respired Δ14C could also be detected in atmospheric measurements. In our ground-level measurements we found large seasonal variation in soil-respired 14CO2 that correlated with soil moisture, which was likely related to root activity. Atmospheric measurements of 14CO2 in the forest canopy (2 to 30m) were used to construct Keeling plots, and these provided larger spatial-scale estimates of respired 14CO2 that largely agreed with the soil-level measurements. In collaboration with the NOAA we also examined temporal patterns of 14CO2 at the Park Falls tall-tower (150m), and found elevated 14CO2 levels during summer months that likely resulted from increased respiration from heterotrophic sources. These results demonstrate that a fingerprint from soil-respired CO2 can be detected in the seasonal patterns of atmospheric 14CO2, even at a regionally-integrating spatial scale far from the soil surface.

  4. Compound specific radiocarbon analyses to apportion sources of combustion products in sedimentary pyrogenic carbon deposits

    NASA Astrophysics Data System (ADS)

    Hanke, Ulrich M.; Schmidt, Michael W. I.; McIntyre, Cameron P.; Reddy, Christopher M.; Wacker, Lukas; Eglinton, Timothy I.

    2016-04-01

    Pyrogenic carbon (PyC) is a collective term for carbon-rich residues comprised of a continuum of products generated during biomass burning and fossil fuel combustion. PyC is a key component of the global carbon cycle due to its slow intrinsic decomposition rate and its ubiquity in the environment. It can originate from natural or anthropogenic vegetation fires, coal mining, energy production, industry and transport. Subsequently, PyC can be transported over long distances by wind and water and can eventually be buried in sediments. Information about the origin of PyC (biomass burning vs. fossil fuel combustion) deposited in estuarine sediments is scarce. We studied the highly anoxic estuarine sediments of the Pettaquamscutt River (Rhode Island, U.S.) in high temporal resolution over 250 years and found different combustion proxies reflect local and regional sources of PyC (Hanke et al. in review; Lima et al. 2003). The polycyclic aromatic hydrocarbons (PAH) originate from long-range atmospheric transport, whereas bulk PyC, detected as benzene polycarboxylic acids (BPCA), mainly stems from local catchment run-off. However, to unambiguously apportion PyC sources, we need additional information, such as compound specific radiocarbon (14C) measurements. We report 14C data for individual BPCA including error analysis and for combustion-related PAH. First results indicate that biomass burning is the main source of PyC deposits, with additional minor contributions from fossil fuel combustion. References Hanke U.M., T.I. Eglinton, A.L.L. Braun, C. Reddy, D.B. Wiedemeier, M.W.I. Schmidt. Decoupled sedimentary records of combustion: causes and implications. In review. Lima, A. L.; Eglinton, T. I.; Reddy, C. M., High-resolution record of pyrogenic polycyclic aromatic hydrocarbon deposition during the 20th century. ES&T, 2003, 37 (1), 53-61.

  5. Variability of surface ocean radiocarbon and stable isotopes in the southwestern Pacific

    NASA Astrophysics Data System (ADS)

    Druffel, Ellen R. M.; Griffin, Sheila

    1999-10-01

    We present high-precision radiocarbon (Δ14C) results and stable isotope (δ18O and δ13C) records for a coral from Heron Island (23°S, 152°E) and new stable isotope (δ18O and δ13C) records for annual coral bands from Abraham Reef (22°S, 153°E) in the southern Great Barrier Reef studied earlier [Druffel and Griffin, 1993]. These tracers provide unique information on the regional water mass history, and together these data allow us to constrain the variability of circulation in the upper Pacific over the past four centuries. First, we observe decreases in δ18O of coral from Abraham Reef and Heron Island, indicating an increase in sea surface temperature and/or a decrease in surface salinity since 1850. Second, the small Suess effect value (Δ14C decrease from 1880 to 1955, due mostly to fossil fuel CO2) observed previously at Abraham Reef[Druffel and Griffin, 1993] is confirmed in the measurements reported here from the Heron Island coral. This value is low compared to those observed in other areas of the ocean [Druffel, 1997; Druffel and Linick, 1978; Nozaki et al., 1978] between 1880 and 1955. Third, we report alterations in the correlation between El Niño events and the occurrence of low Δ14C, which is indicative of long-term change(s) in circulation in the SW Pacific. The Δ14C shifts reported here are not large, but even small temporal changes in prebomb Δ14C suggest that important changes in the large-scale state of the ocean have occurred, such as a temporal change in circulation.

  6. Determination of the Prebomb Southern (Antartic) Ocean Radiocarbon in Organic Matter

    SciTech Connect

    Guilderson, T P

    2001-02-26

    The Southern Hemisphere is an important and unique region of the world's oceans for water-mass formation and mixing, upwelling, nutrient utilization, and carbon export. In fact, one of the primary interests of the oceanographic community is to decipher the climatic record of these processes in the source or sink terms for Southern Ocean surface waters in the CO{sub 2} balance of the atmosphere. Current coupled ocean-atmosphere modeling efforts to trace the input of CO{sub 2} into the ocean imply a strong sink of anthropogenic CO{sub 2} in the southern ocean. However, because of its relative inaccessibility and the difficulty in directly measuring CO{sub 2} fluxes in the Southern Ocean, these results are controversial at best. An accepted diagnostic of the exchange of CO{sub 2} between the atmosphere and ocean is the prebomb distribution of radiocarbon in the ocean and its time-history since atmospheric nuclear testing. Such histories of {sup 14}C in the surface waters of the Southern Ocean do not currently exist, primarily because there are few continuous biological archives (e.g., in corals) such as those that have been used to monitor the {sup 14}C history of the tropics and subtropics. One of the possible long-term archives is the scallop Adamussium collbecki. Although not independently confirmed, relatively crude growth rate estimates of A. collbecki indicate that it has the potential to provide continuous 100 year time-series. We are exploring the suitability of this potential archive.

  7. Projecting mechanics into morphospace: disparity in the feeding system of labrid fishes.

    PubMed Central

    Hulsey, C Darrin; Wainwright, Peter C

    2002-01-01

    In no group of organisms has the link between species richness, morphological disparity, disparity in mechanics and functional or ecological diversification been made explicit. As a step towards integrating these measures of diversity, we examine how the mechanics of the anterior-jaw four-bar linkages of 104 species of Great Barrier Reef (GBR) labrid fishes maps into a scale-independent morphospace. As predicted from theory, no relationship exists between overall size and the mechanics of velocity and force transmission in labrid anterior-jaw linkages. Nonetheless, mechanics associated with the anterior jaw appear to have constrained diversification of labrid anterior-jaw morphology. Furthermore, simulations depict a generally nonlinear relationship between the length of individual links and transmission of motion. In addition, no relationship was found between morphological disparity and mechanical disparity among the most species-rich labrid groups from the GBR. It is also established that regions of morphospace equivalent in morphological disparity differ over nearly an order of magnitude in mechanical disparity. These results illustrate that without an explicit interpretation of the consequences of per unit change in morphology, conclusions about diversification drawn only from morphological disparity may be misleading. PMID:11839201

  8. Year-round Source Contributions of Fossil Fuel and Biomass Combustion to Elemental Carbon on the North Slope Alaska Utilizing Radiocarbon Analysis

    NASA Astrophysics Data System (ADS)

    Barrett, T. E.; Gustafsson, O.; Winiger, P.; Moffett, C.; Back, J.; Sheesley, R. J.

    2015-12-01

    It is well documented that the Arctic has undergone rapid warming at an alarming rate over the past century. Black carbon (BC) affects the radiative balance of the Arctic directly and indirectly through the absorption of incoming solar radiation and by providing a source of cloud and ice condensation nuclei. Among atmospheric aerosols, BC is the most efficient absorber of light in the visible spectrum. The solar absorbing efficiency of BC is amplified when it is internally mixed with sulfates. Furthermore, BC plumes that are fossil fuel dominated have been shown to be approximately 100% more efficient warming agents than biomass burning dominated plumes. The renewal of offshore oil and gas exploration in the Arctic, specifically in the Chukchi Sea, will introduce new BC sources to the region. This study focuses on the quantification of fossil fuel and biomass combustion sources to atmospheric elemental carbon (EC) during a year-long sampling campaign in the North Slope Alaska. Samples were collected at the Department of Energy Atmospheric Radiation Measurement (ARM) climate research facility in Barrow, AK, USA. Particulate matter (PM10) samples collected from July 2012 to June 2013 were analyzed for EC and sulfate concentrations combined with radiocarbon (14C) analysis of the EC fraction. Radiocarbon analysis distinguishes fossil fuel and biomass burning contributions based on large differences in end members between fossil and contemporary carbon. To perform isotope analysis on EC, it must be separated from the organic carbon fraction of the sample. Separation was achieved by trapping evolved CO2 produced during EC combustion in a cryo-trap utilizing liquid nitrogen. Radiocarbon results show an average fossil contribution of 85% to atmospheric EC, with individual samples ranging from 47% to 95%. Source apportionment results will be combined with back trajectory (BT) analysis to assess geographic source region impacts on the EC burden in the western Arctic.

  9. Future research directions for understanding neighborhood contributions to health disparities.

    PubMed

    Osypuk, T L

    2013-06-01

    This paper proposes several promising future directions for neighborhood research to address health inequalities. First, there is a need to apply a Geography of Opportunity framework to understand how vast spatial (neighborhood, regional) inequality translates into health inequality. Such a framework highlights inequality that unfolds across an entire region, as well as the continuing significance of race/ethnicity for producing disparities in health and in the social determinants of health. The Geography of Opportunity framework also points to some of the methodological limitations of current neighborhood-health studies, given the structure of neighborhood racial inequality in the US for estimating how important neighborhoods are for producing racial health disparities. Second, there is a need to incorporate life-course concepts, data, and methods, including to model residential histories, neighborhood temporal change and residential mobility, starting early in life. A life-course focus would help inform when in life neighborhoods matter most for health and health inequalities, as well as improve exposure assessment of residential contexts. Third, we must model mechanisms linking neighborhoods and health, including the role of individual and household socioeconomic status. Lastly, we need to more meaningfully integrate social determinants of health, including drawing on policy evaluations that aim to improve neighborhood environments or that aim to expand household neighborhood choice. Doing so would inform how specific modifiable neighborhood exposures stimulated by policy may influence health and health disparities. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  10. Demography of the Early Neolithic Population in Central Balkans: Population Dynamics Reconstruction Using Summed Radiocarbon Probability Distributions.

    PubMed

    Porčić, Marko; Blagojević, Tamara; Stefanović, Sofija

    2016-01-01

    The Central Balkans region is of great importance for understanding the spread of the Neolithic in Europe but the Early Neolithic population dynamics of the region is unknown. In this study we apply the method of summed calibrated probability distributions to a set of published radiocarbon dates from the Republic of Serbia in order to reconstruct population dynamics in the Early Neolithic in this part of the Central Balkans. The results indicate that there was a significant population growth after ~6200 calBC, when the Neolithic was introduced into the region, followed by a bust at the end of the Early Neolithic phase (~5400 calBC). These results are broadly consistent with the predictions of the Neolithic Demographic Transition theory and the patterns of population booms and busts detected in other regions of Europe. These results suggest that the cultural process that underlies the patterns observed in Central and Western Europe was also in operation in the Central Balkan Neolithic and that the population increase component of this process can be considered as an important factor for the spread of the Neolithic as envisioned in the demic diffusion hypothesis.

  11. Demography of the Early Neolithic Population in Central Balkans: Population Dynamics Reconstruction Using Summed Radiocarbon Probability Distributions

    PubMed Central

    2016-01-01

    The Central Balkans region is of great importance for understanding the spread of the Neolithic in Europe but the Early Neolithic population dynamics of the region is unknown. In this study we apply the method of summed calibrated probability distributions to a set of published radiocarbon dates from the Republic of Serbia in order to reconstruct population dynamics in the Early Neolithic in this part of the Central Balkans. The results indicate that there was a significant population growth after ~6200 calBC, when the Neolithic was introduced into the region, followed by a bust at the end of the Early Neolithic phase (~5400 calBC). These results are broadly consistent with the predictions of the Neolithic Demographic Transition theory and the patterns of population booms and busts detected in other regions of Europe. These results suggest that the cultural process that underlies the patterns observed in Central and Western Europe was also in operation in the Central Balkan Neolithic and that the population increase component of this process can be considered as an important factor for the spread of the Neolithic as envisioned in the demic diffusion hypothesis. PMID:27508413

  12. Gender disparity in late-life cognitive functioning in India: findings from the longitudinal aging study in India.

    PubMed

    Lee, Jinkook; Shih, Regina; Feeney, Kevin; Langa, Kenneth M

    2014-07-01

    To examine gender disparities in cognitive functioning in India and the extent to which education explains this disparity in later life. This study uses baseline interviews of a prospective cohort study of 1,451 community-residing adults 45 years of age or older in four geographically diverse states of India (Karnataka, Kerala, Punjab, Rajasthan). Data collected during home visits includes cognitive performance tests, and rich sociodemographic, health, and psychosocial variables. The cognitive performance tests include episodic memory, numeracy, and a modified version of the Mini-Mental State Examination. We find gender disparity in cognitive function in India, and this disparity is greater in the north than the south. We also find that gender disparities in educational attainment, health, and social and economic activity explain the female cognitive disadvantage in later life. We report significant gender disparities in cognitive functioning among older Indian adults, which differ from gender disparities in cognition encountered in developed countries. Our models controlling for education, health status, and social and economic activity explain the disparity in southern India but not the region-specific disparity in the northern India. North Indian women may face additional sources of stress associated with discrimination against women that contribute to persistent disadvantages in cognitive functioning at older ages. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Radiocarbon calibration uncertainties during the last deglaciation: Insights from new floating tree-ring chronologies

    NASA Astrophysics Data System (ADS)

    Adolphi, Florian; Muscheler, Raimund; Friedrich, Michael; Güttler, Dominik; Wacker, Lukas; Talamo, Sahra; Kromer, Bernd

    2017-08-01

    Radiocarbon dating is the most commonly used chronological tool in archaeological and environmental sciences dealing with the past 50,000 years, making the radiocarbon calibration curve one of the most important records in paleosciences. For the past 12,560 years, the radiocarbon calibration curve is constrained by high quality tree-ring data. Prior to this, however, its uncertainties increase rapidly due to the absence of suitable tree-ring 14C data. Here, we present new high-resolution 14C measurements from 3 floating tree-ring chronologies from the last deglaciation. By using combined information from the current radiocarbon calibration curve and ice core 10Be records, we are able to absolutely date these chronologies at high confidence. We show that our data imply large 14C-age variations during the Bølling chronozone (Greenland Interstadial 1e) - a period that is currently characterized by a long 14C-age plateau in the most recent IntCal13 calibration record. We demonstrate that this lack of structure in IntCal13 may currently lead to erroneous calibrated ages by up to 500 years.

  14. Materials Science Challenges in Radiocarbon Dating: The Case of Archaeological Plasters

    NASA Astrophysics Data System (ADS)

    Boaretto, Elisabetta; Poduska, Kristin M.

    2013-04-01

    Structural, compositional, and isotopic characterization techniques are critically important to help identify pristine materials that are suitable for accurate and precise radiocarbon dating. Lime plasters, cements, and mortars are ideal materials for establishing firm and secure dates in the archaeological record as human-constructed living surfaces and installations. However, the often complex composite structures of plasters and their susceptibility to diagenetic processes have impeded the development of a reliable and reproducible method to identify the best specimens for dating. In this article we present an overview of the plaster production process and the radiocarbon dating method. We explain how material characterization techniques and radiocarbon dating can be integrated to make progress toward the ultimate goal of relating radiocarbon concentrations with environmental, sample preparation, and/or diagenetic conditions in which the plaster existed. A key aspect of this strategy relies on implementing material characterization techniques in the field, during an excavation, to help establish the archaeological context in which datable material is recovered.

  15. Revised age of deglaciation of Lake Emma based on new radiocarbon and macrofossil analyses

    USGS Publications Warehouse

    Elias, S.A.; Carrara, P.E.; Toolin, L.J.; Jull, A.J.T.

    1991-01-01

    Previous radiocarbon ages of detrital moss fragments in basal organic sediments of Lake Emma indicated that extensive deglaciation of the San Juan Mountains occurred prior to 14,900 yr B.P. (Carrara et al., 1984). Paleoecological analyses of insect and plant macrofossils from these basal sediments cast doubt on the reliability of the radiocarbon ages. Subsequent accelerator radiocarbon dates of insect fossils and wood fragments indicate an early Holocene age, rather than a late Pleistocene age, for the basal sediments of Lake Emma. These new radiocarbon ages suggest that by at least 10,000 yr B.P. deglaciation of the San Juan Mountains was complete. The insect and plant macrofossils from the basal organic sediments indicate a higher-than-present treeline during the early Holocene. The insect assemblages consisted of about 30% bark beetles, which contrasts markedly with the composition of insects from modern lake sediments and modern specimens collected in the Lake Emma cirque, in which bark beetles comprise only about 3% of the assemblages. In addition, in the fossil assemblages there were a number of flightless insect species (not subject to upslope transport by wind) indicative of coniferous forest environments. These insects were likewise absent in the modern assemblage. ?? 1991.

  16. Radiocarbon calibration uncertainties during the last deglaciation: Insights from new floating tree-ring chronologies

    NASA Astrophysics Data System (ADS)

    Adolphi, Florian; Muscheler, Raimund; Friedrich, Michael; Güttler, Dominik; Wacker, Lukas; Talamo, Sahra; Kromer, Bernd

    2017-04-01

    Radiocarbon dating is the most commonly used chronological tool in archaeological and environmental sciences dealing with the past 50,000 years, making the radiocarbon calibration curve one of the most important records in paleosciences. For the past 12,560 years, the radiocarbon calibration curve is constrained by high quality tree-ring data. Prior to this, however, its uncertainties increase rapidly due to the absence of suitable tree-ring 14C data. Here, we present high-resolution 14C measurements from 3 new floating tree-ring chronologies from the last deglaciation. By using combined information from the current radiocarbon calibration curve and ice core 10Be records, we are able to absolutely date these chronologies at high confidence. We show that our data imply large 14C-age variations during the Bølling chronozone (Greenland Interstadial GI-1e) - a period that is currently characterized by a long 14C-age plateau in the most recent IntCal13 calibration record. We demonstrate that this lack of structure in IntCal13 may currently lead to erroneous calibrated ages by up to 500 years.

  17. Radiocarbon dating of American pika fecal pellets provides insights into population extirpations and climate refugia

    Treesearch

    Constance I. Millar; Katherine Heckman; Christopher Swanston; Karena Schmidt; Robert D. Westfall; Diane L. Delany

    2014-01-01

    The American pika (Ochotona princeps) has become a species of concern for its sensitivity to warm temperatures and potential vulnerability to global warming. We explored the value of radiocarbon dating of fecal pellets to address questions of population persistence and timing of site extirpation. Carbon was extracted from pellets collected at 43...

  18. RADIOCARBON 14C MEASUREMENTS ON ATMOSPHERIC SAMPLES OF PARTICULATE MATTER (& VOLATILE ORGANIC COMPOUNDS)

    EPA Science Inventory

    Following a brief history of radiocarbon work at EPA since the 1980's, the presentation focuses on recent non-winter measurements for PM-2.5 in the Southeastern U.S. (Houston, TX; Nashville, TN; and particularly, Tampa, FL) and what the measurements suggest about the importance o...

  19. Co-Development of Conceptual Understanding and Critical Attitude: Analyzing Texts on Radiocarbon Dating

    ERIC Educational Resources Information Center

    Décamp, N.; Viennot, L.

    2015-01-01

    This research documents the impact of a teaching interview aimed at developing a critical attitude in students, and focused on a particular topic: radiocarbon dating. This teaching interview is designed to observe students' reaction to limited written explanations of the phenomenon under study, and their possible frustration or intellectual…

  20. Co-Development of Conceptual Understanding and Critical Attitude: Analyzing Texts on Radiocarbon Dating

    ERIC Educational Resources Information Center

    Décamp, N.; Viennot, L.

    2015-01-01

    This research documents the impact of a teaching interview aimed at developing a critical attitude in students, and focused on a particular topic: radiocarbon dating. This teaching interview is designed to observe students' reaction to limited written explanations of the phenomenon under study, and their possible frustration or intellectual…

  1. Rapid revelation of radiocarbon records with laser ablation Accelerator Mass Spectrometry.

    PubMed

    Münsterer, Caroline; Wacker, Lukas; Hattendorf, Bodo; Christl, Marcus; Koch, Joachim; Dietiker, Rolf; Synal, Hans-Arno; Günther, Detlef

    2014-01-01

    By focusing high-intensity laser pulses on carbonate samples carbon dioxide is generated and can be directly introduced into the gas ion source (GIS) of an Accelerator Mass Spectrometer (AMS). This new technique allows rapid radiocarbon analyses at high spatial resolution. The design of the deignated laser ablation cell as well as first results on a stalagmite sample are presented.