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. 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

  3. 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…

  4. 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.

  5. 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…

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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. PMID:27573138

  12. Regional Disparities and Public Policy in Tunisian Education.

    ERIC Educational Resources Information Center

    Jones, Marie T.

    1986-01-01

    Shows how Tunisia's national educational program is implemented unevenly in different regions with resulting disadvantages for rural populations, especially rural girls and women. Specifies ways the politics and public policy appear to influence regional differences in educational outcomes. Examines educational, economic, and political…

  13. 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. PMID:24486917

  14. 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

  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. 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

    2015-01-01

    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. PMID:25716410

  17. Regional Disparities in the Distribution of Healthcare Workers: Evidence From Iran, Chaharmahal and Bakhtiari Province

    PubMed Central

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

    2015-01-01

    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. PMID:25716410

  18. Characterization of regional carbonaceous particulate matter in Central Texas using combined radiocarbon and organic tracer source apportionment

    NASA Astrophysics Data System (ADS)

    Sheesley, R. J.; Barrett, T.; Nallathamby, P. D.

    2012-12-01

    Atmospheric particulate matter (PM) in Texas can be transported readily among urban, rural and natural areas. Depending upon the season and transport conditions, major Texas cities can readily impact PM loadings in urban and rural areas across the state. To begin to assess the potential impacts of anthropogenic and biogenic sources on carbonaceous aerosol loading in Central Texas, source apportionment modeling is needed. For this study, two rigorous models have been combined to provide better constraints on potential emission sources; organic tracer chemical mass balance modeling and radiocarbon source apportionment have been combined to provide complementary information on primary emission contributions (motor vehicle exhaust and biomass burning) and total fossil vs modern (biogenic plus biomass burning) contributions to carbonaceous PM. Preliminary results indicate more than 50% of carbonaceous PM is from biogenic/biomass burning emissions during the summer study period. Organic tracer CMB will be added to increase specificity in the fossil and modern carbon emission sources (ie. motor vehicle exhaust and biomass burning). This detailed, top-down study can provide crucial constraints for future regional, bottom-up approaches which focus on emissions inventories.

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

    PubMed

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

    2014-05-01

    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

  20. 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

  1. Parietal Reach Region Encodes Reach Depth Using Retinal Disparity and Vergence Angle Signals

    PubMed Central

    Bhattacharyya, Rajan; Musallam, Sam; Andersen, Richard A.

    2009-01-01

    Performing a visually guided reach requires the ability to perceive the egocentric distance of a target in three-dimensional space. Previous studies have shown that the parietal reach region (PRR) encodes the two-dimensional location of frontoparallel targets in an eye-centered reference frame. To investigate how a reach target is represented in three dimensions, we recorded the spiking activity of PRR neurons from two rhesus macaques trained to fixate and perform memory reaches to targets at different depths. Reach and fixation targets were configured to explore whether neural activity directly reflects egocentric distance as the amplitude of the required motor command, which is the absolute depth of the target, or rather the relative depth of the target with reference to fixation depth. We show that planning activity in PRR represents the depth of the reach target as a function of disparity and fixation depth, the spatial parameters important for encoding the depth of a reach goal in an eye centered reference frame. The strength of modulation by disparity is maintained across fixation depth. Fixation depth gain modulates disparity tuning while preserving the location of peak tuning features in PRR neurons. The results show that individual PRR neurons code depth with respect to the fixation point, that is, in eye centered coordinates. However, because the activity is gain modulated by vergence angle, the absolute depth can be decoded from the population activity. PMID:19439678

  2. Regional Variation of Racial Disparities in Mental Health Service Use Among Older Adults

    PubMed Central

    Kim, Giyeon

    2013-01-01

    Purpose: Given the paucity of research on the role of geography in mental health care, this study examined whether racial differences in mental health service use varied across geographic regions among older adults. Design and Methods: Drawn from the Collaborative Psychiatric Epidemiology Surveys (CPES), blacks (n = 1,008) and whites (n = 1,870) aged 60 and older were selected for analysis. Logistic regression analyses were conducted. Results: Results showed significant racial disparities in mental health service use in the overall sample, as well as significant variation by region. Although no racial differences were observed in the Northeast, West, or Midwest regions, black elders in the South were significantly less likely than whites to use mental health services (odds ratios [OR], 2.08; 95% confidence interval [CI], 1.34–3.23). Implications: The findings suggest that improving the access to mental health care in certain regions, the South in particular, may be essential to reduce racial disparities at the national level. Policy implications are discussed. PMID:22859437

  3. 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.

  4. 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.

  5. 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., K.; 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. ?? 2009 Coastal Education and Research Foundation.

  6. Regional Disparities in Obesity Prevalence in the United States: A Spatial Regime Analysis

    PubMed Central

    Myers, Candice A.; Slack, Tim; Martin, Corby K.; Broyles, Stephanie T.; Heymsfield, Steven B.

    2014-01-01

    Objective Significant clusters of high and low obesity counties have been demonstrated across the United States (U.S.). This study examined regional disparities in obesity prevalence and differences in the related structural characteristics across regions of the U.S. Design and Methods Drawing on model-based estimates from the Centers for Disease Control and Prevention, regional differences in county-level adult obesity prevalence (percent of the adult population [≥ 20 years] that was obese [BMI≥30kg/m2] within a county, 2009) were assessed with a LISA (Local Indicators of Spatial Association) analysis to identify geographic concentrations of high and low obesity levels. We utilized regional regime analysis to identify factors that were differentially associated with obesity prevalence between regions of the U.S. Results High and low obesity county clusters and the effect of a number of county-level characteristics on obesity prevalence differed significantly by region. These included the positive effect of African American populations in the South, the negative effect of Hispanic populations in the Northeast, and the positive effect of unemployed workers in the Midwest and West. Conclusions Our findings suggest the need for public health policies and interventions that account for different regional characteristics underlying obesity prevalence variation across the U.S. PMID:25521074

  7. Reducing asthma disparities by addressing environmental inequities: a case study of regional asthma management and prevention's advocacy efforts.

    PubMed

    Lamb, Anne Kelsey; Ervice, Joel; Lorenzen, Kathryn; Prentice, Bob; White, Shannon

    2011-01-01

    Regional Asthma Management and Prevention describes its collaborative approach to address a social determinant of health--air quality--and the associated inequities that have led to asthma disparities impacting African American and Latino communities in the San Francisco Bay Area. The strategies, aimed at decreasing diesel pollution in disproportionately impacted communities, span the levels of the socioecological model, with an emphasis on policy outcomes. Regional Asthma Management and Prevention describes how this work fits within a larger comprehensive approach to address asthma disparities encompassing several components, ranging from clinical management to environmental protection. PMID:21160331

  8. Regional Disparities in Sedentary Behaviors and Meal Frequency in Iranian Adolescents: The CASPIAN-III Study

    PubMed Central

    Baygi, Fereshteh; Heshmat, Ramin; Kelishadi, Roya; Mohammadi, Fatemeh; Motlagh, Mohammad Esmail; Ardalan, Gelayol; Asayesh, Hamid; Larijani, Bagher; Qorbani, Mostafa

    2015-01-01

    Background: The prevalence of obesity is increasing among Iranian youngsters like other developing countries. Objectives: This study was conducted to assess regional disparities in sedentary behaviors and meal frequency in Iranian adolescents. Patients and Methods: In this national survey, 5682 students aged 10 - 18 years from urban and rural districts of 27 provinces of Iran were selected via stratified multi-stage sampling method. The country was classified into four sub-national regions, based on criteria of the combination of geography and socioeconomic status (SES). Mean of meal frequency and physical activity levels as well as prevalence of omitting meals and sedentary behavior were compared across regions with different SES after stratifying with sex and age group. Results: Meal frequency in lower socio-economic regions was significantly higher than two other regions in 10 - 13 and 10 - 18 years old groups (P trend < 0.001). However, the mean of working hours with computer was linearly increased with increasing the SES in studied regions (P trend < 0.001), whereas the corresponding figure was not significant for the mean of watching TV (P trend > 0.05). Frequency of adolescents omitting their meals was higher in higher SES regions especially in West Iran (P < 0.001) in 10 - 13 years old age group. Having personal computer and working with it more than two hours per day mainly was observed in central Iran which ranked as the highest SES group. Conclusions: Efforts to ensure Iranian youth meet healthy food habits and screen time guidelines include limiting access to screen technologies and encouraging parents to monitor their own screen time is required. PMID:26195993

  9. 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

  10. 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. PMID:25222751

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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

  16. Regional disparities in hospitalization charges for patients undergoing craniotomy for tumor resection in New York State: correlation with outcomes.

    PubMed

    Missios, Symeon; Bekelis, Kimon

    2016-06-01

    There is increasing regulatory pressure for cost containment in neuro-oncology, and rationalization of the observed regional disparities. We investigated the presence of such disparities in New York State and examined the impact of risk adjustment on the magnitude of this variation. We performed a cohort study involving patients with brain tumors (gliomas, metastases, or meningiomas), who underwent craniotomy for resection from 2009 to 2013, and were registered in the Statewide Planning and Research Cooperative System (SPARCS) database. A linear regression model was utilized for risk-adjustment of inpatient charges using socioeconomic factors and comorbidities. Hospitals with fewer than 20 craniotomies were excluded. 13,535 patients underwent treatment, including 5032 (37.2 %) gliomas, 4858 (35.9 %) metastases, and 3645 (26.9 %) meningiomas. Unadjusted median hospitalization charges ranged from $22,954 to $177,398 at the hospital level, and $30,086 to $159,281 at the county level. Despite extensive risk-adjustment we observed persistent disparities with median hospitalization charges ranging from $40,455 to $124,691 at the hospital level, and $53,999 to $94,844 at the county level. Analysis of variance (ANOVA) demonstrated that these disparities were significant at the facility and the county level (P < 0.0001). Increased charges were not associated with shorter LOS (r = 0.10, P = 0.41), or lower rates of death (r = 0.09, P = 0.46), and unfavorable discharge (r = 0.24, P = 0.06). Using a comprehensive all-payer cohort of patients with brain tumors in New York State we identified wide disparities at the hospital and the county level despite comprehensive risk-adjustment. Increased charges were not associated with shorter LOS, or lower rates of death and unfavorable discharge. PMID:27072560

  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. Source apportionment using radiocarbon and organic tracers for PM2.5 carbonaceous aerosols in Guangzhou, South China: contrasting local- and regional-scale haze events.

    PubMed

    Liu, Junwen; Li, Jun; Zhang, Yanlin; Liu, Di; Ding, Ping; Shen, Chengde; Shen, Kaijun; He, Quanfu; Ding, Xiang; Wang, Xinming; Chen, Duohong; Szidat, Sönke; Zhang, Gan

    2014-10-21

    We conducted a source apportionment and investigated the atmospheric behavior of carbonaceous aerosols during hazy and normal days using radiocarbon ((14)C) and biomass burning/secondary organic aerosol (SOA) tracers during winter in Guangzhou, China. Haze episodes were formed either abruptly by local emissions or through the accumulation of particles transported from other areas. The average contributions of fossil carbon to elemental carbon (EC), water-insoluble organic carbon, and water-soluble organic carbon were 71 ± 10%, 40 ± 6% and 33 ± 3%, respectively. High contributions of fossil carbon to EC (80-90%) were observed for haze samples that were substantially impacted by local emissions, as were the highest (lowest) ratios for NO3(-)/SO4(2-) (OC/EC), which indicates that these particles mainly came from local vehicle exhaust. Low contributions of fossil carbon to EC (60-70%) were found for haze particles impacted by regional transport. Secondary organic carbon (SOC) calculated using SOA tracers accounts for only ∼ 20% of the SOC estimated by (14)C, which is probably because some important volatile organic carbons are not taken into account in the SOA tracer calculation method and because of the large discrepancy in ambient conditions between the atmosphere and smog chambers. A total of 33 ± 11% of the SOC was of fossil origin, a portion of which could be influenced by humidity. PMID:25264588

  19. 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,…

  20. 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.

  1. 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.

  2. Pre- and post-bomb radiocarbon in fish otoliths

    NASA Astrophysics Data System (ADS)

    Kalish, John M.

    1993-02-01

    Measurements of radiocarbon in seawater dissolved inorganic carbon (DIC), or suitable proxies such as hermatypic corals, are a valuable source of information on carbon flux and ocean circulation. However, knowledge of the global distribution of both pre- and post-bomb radiocarbon is limited due to the sources of these data. Suitable hermatypic corals are restricted to shallow tropical and subtropical waters and oceanographic collections of seawater are prohibitively expensive. What is needed is a proxy for ocean radiocarbon that can be collected at most latitudes and depths, and which can be reliably aged. Here I report accelerator mass spectrometry analyses of radiocarbon from selected regions of fish otoliths and show that such measurements are suitable for determining both pre- and post-bomb radiocarbon in all oceans and at most depths. Radiocarbon data obtained from otoliths can extend our knowledge of carbon flux in the oceans and atmosphere and help to develop further understanding of the fate of atmospheric CO 2 and ocean circulation. The data presented here represent the first pre- and post-bomb time series of radiocarbon levels from temperate waters. Furthermore, I demonstrate that the dramatic increase in radiocarbon in the atmosphere and oceans, attributable to the atmospheric testing of thermonuclear bombs during the 1950's and 1960's, provides a chemical mark on fish otoliths that is suitable for the validation of age in fishes.

  3. 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

  4. 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

  5. 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.

  6. 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)

  7. Traumatic Brain Injury Results in Disparate Regions of Chondroitin Sulfate Proteoglycan Expression That Are Temporally Limited

    PubMed Central

    Harris, N.G.; Carmichael, S.T.; Hovda, D.A.; Sutton, R.L.

    2010-01-01

    Axonal injury is a major hallmark of traumatic brain injury (TBI), and it seems likely that therapies directed toward enhancing axon repair could potentially improve functional outcomes. One potential target is chondroitin sulfate proteoglycans (CSPGs), which are major axon growth inhibitory molecules that are generally, but not always, up-regulated after central nervous system injury. The current study was designed to determine temporal changes in cerebral cortical mRNA or protein expression levels of CSPGs and to determine their regional localization and cellular association by using immunohistochemistry in a controlled cortical impact model of TBI. The results showed significant increases in versican mRNA at 4 and 14 days after TBI but no change in neurocan, aggrecan, or phosphacan. Semiquantitative Western blot (WB) analysis of cortical CSPG protein expression revealed a significant ipsilateral decrease of all CSPGs at 1 day after TBI. Lower CSPG protein levels were sustained until at least 14 days, after which the levels began to normalize. Immunohistochemistry data confirm previous reports of regional increases in CSPG proteins after CNS injury, seen primarily within the developing glial scar after TBI, but also corroborate the WB data by revealing wide areas of pericontusional tissue that are deficient in both extracellular and perineuronal net-associated CSPGs. Given the evidence that CSPGs are largely inhibitory to axonal growth, we interpret these data to indicate a potential for regional spontaneous plasticity after TBI. If this were the case, the gradual normalization of CSPG proteins over time postinjury would suggest that this may be temporally as well as regionally limited. PMID:19437549

  8. 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

  9. 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

  10. Projections of atmospheric radiocarbon content to 2100

    NASA Astrophysics Data System (ADS)

    Graven, Heather

    2014-05-01

    The radiocarbon content of atmospheric CO2 has undergone dramatic changes over the past century. Radiocarbon in CO2 has been diluted by the combustion of 14C-free fossil fuels since the industrial revolution, causing a slow decline in the relative abundance of 14C to total carbon (Δ14C) in the early 1900s. This decline was interrupted by nuclear weapons testing in the 1950s and 60s, which nearly doubled the atmospheric inventory of 14C. Following the extraordinary rise in radiocarbon content, a quasi-exponential decrease was observed as excess radiocarbon was assimilated by carbon reservoirs in the ocean and on land. Recently, fossil fuel emissions have once again become the dominant influence on the long-term trend in Δ14C of CO2. This presentation will investigate the trajectory of atmospheric Δ14C to 2100 in relation to the Representative Concentration Pathways (RCPs) using a simple carbon cycle model. In all scenarios, Δ14C of CO2 is projected to drop below the zero per mil level in the next decade. Simulated atmospheric Δ14C is lower than -200 per mil in 2100 in the scenario with the largest growth in fossil fuel emissions, while the most ambitious emission reductions are projected to sustain Δ14C near zero per mil. The presentation will discuss the implications of these changes in atmospheric composition on isotopic disequilibria and net fluxes of radiocarbon between different reservoirs, including the sensitivity of atmospheric Δ14C to fossil fuel emissions on global and regional scales.

  11. 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)

  12. Exploring the disparities of regional health care expenditures in Switzerland: some empirical evidence.

    PubMed

    Reich, Oliver; Weins, Cornelia; Schusterschitz, Claudia; Thöni, Magdalena

    2012-04-01

    This study investigates the determinants of regional variations in health care expenditures (HCE) in Switzerland, since there are significant differences between cantons per capita HCE. The empirical analysis contributes to the discussion on the outcome of federalism in the Swiss health care system by improving the understanding of the determinants of the differences in HCE. Our econometric estimations indicate that HCE are significantly related to the density of specialist physicians, density of dispensing doctors, per capita income, proportion of managed care, medical and technological progress and socio-economic factors. Due to the presumptive importance of the organisation of ambulatory care, we suggest policy makers should particularly concentrate on promoting the supply of managed care models in Switzerland. Supporting the development of managed care may help to countervail some of the influences which tend to lead to higher cantonal health expenditures. PMID:21290253

  13. 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

  14. Radiocarbon Ages from Two Submerged Strandline Features in the Western Gulf of Maine and a Sea-Level Curve for the Northeastern Massachusetts Coastal Region

    USGS Publications Warehouse

    Oldale, R.N.; Colman, Steven M.; Jones, Glenn A.

    1993-01-01

    New radiocarbon dates provide ages for two submerged strandline features on the Massachusetts inner shelf. These ages provide limited control on a relative sea-level (RSL) curve for the late Wisconsinan and Holocene. The curve indicates a late Wisconsinan high stand of RSL of +33 m about 14,000 yr ago and a very short-lived relative low stand of about -43 m at about 12,000 yr ago followed by a rise to present sea level. Rapid changes of RSL around 12,000 yr ago may be related to changes in global glacial meltwater discharge and eustatic sea-level change shown by dated corals off Barbados. Variations in the magnitude and timing of RSL change from south to north along the coast of the western Gulf of Maine are due to greater crustal depression and later deglaciation to the north.

  15. 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)

  16. Investigating global change and fish biology with fish otolith radiocarbon

    NASA Astrophysics Data System (ADS)

    Kalish, John M.

    1994-06-01

    Fish otoliths, calcium carbonate gravity and auditory receptors in the membranous labyrinths of teleost fish, can provide radiocarbon data that are valuable to a wide range of disciplines. For example, the first pre- and post-bomb time series of radiocarbon levels from northern or southern hemisphere temperate oceans was obtained by carrying out accelerator mass spectrometry analyses on selected regions of fish otoliths. These data can provide powerful constraints on both carbon cycle models and ocean general circulation models. Because fish otoliths can serve as a proxy of radiocarbon in seawater dissolved inorganic carbon in all oceans and at most depths, there is considerable scope for further investigations of otolith radiocarbon in relation to both oceanography and global change. In addition to applications relevant to global change, fish otoliths are also valuable sources of information on the age, growth, and ecology of fishes, with age being among the most important parameters in population modelling and fisheries management. Use of the bomb radiocarbon chronometer to validate fish age determination methods offers considerable advantages over traditional forms of age validation and promises to become a standard tool in fish biology and fisheries management. Radiocarbon data from otoliths can also provide valuable information on the ecology of fishes and has already provided surprising information relevant to the ecology of some deep-sea fishes.

  17. 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. PMID:26018117

  18. 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

  19. Radiocarbon analysis and Quaternary Geochronology

    NASA Astrophysics Data System (ADS)

    Hajdas, Irka

    2014-05-01

    Reliable chronological frames are basis of all studies of the past. Dependent on type of the studies and records various methods are used to date natural archives. Most of natural archives of the last 50 kyr such as: lake sediments, peat sections, soils, tree rings and the ocean sediments can be dated using radiocarbon dating method. Recent developments in the AMS dating technique allow measurements of radiocarbon ages on sample containing fractions of mg of C, which opens new opportunities for dating paleo records. Some examples of recent studies of various records will be presented.

  20. 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. PMID:26223935

  1. Mutation detection analysis of a region of 16S-like ribosomal RNA gene of Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii

    PubMed Central

    Parija, Subhash Chandra; Khairnar, Krishna

    2008-01-01

    Background The level of intra-species genetic variation in Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii populations in a localized geographic area, like Puducherry, India, remains unknown. Methods In the present study the existence of genetic variation in the nested multiplex polymerase chain reaction (NM-PCR) amplified region of the 16S-like ribosomal RNA genes of E. histolytica, E. dispar and E. moshkovskii was investigated by riboprinting and single strand conformation polymorphism (SSCP) analysis. Results We found that 70 stool specimens were positive for E. histolytica, 171 stool specimens were positive for E. dispar, and 37 stool specimens were positive for E. moshkovskii by NM-PCR. Ninety liver abscess pus specimens, 21 urine specimens, and 8 saliva specimens were positive for E. histolytica by NM-PCR. Riboprinting analysis detected a mutation in the PCR product of only one E. histolytica isolate from a stool specimen. However, SSCP analysis detected mutations in the PCR products of five E. histolytica isolates and three E. moshkovskii isolates from stool specimens, and one E. histolytica isolate from a saliva specimen. The mutations detected by riboprinting and SSCP analysis were confirmed by sequencing. All the nucleotide sequences showing mutations in this study have already been deposited into the NCBI GenBank database under accession numbers [GenBank: EF682200 to GenBank: EF682208]. Conclusion The present study has revealed the subsistence of mutations in the ribosomal RNA genes of E. histolytica and E. moshkovskii, which points towards the existence of intra-species genetic variation in E. histolytica and E. moshkovskii isolates infecting humans. PMID:18822136

  2. 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

    2016-01-01

    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

  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 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

  4. 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.

  5. 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).

  6. Radiocarbon in hydrologic systems containing dissolved magmatic carbon dioxide

    SciTech Connect

    Rose, T.P.; Davisson, M.L.

    1996-09-06

    In regions of active volcanism, the presence of magmatic carbon dioxide (CO{sub 2}) in regional hydrologic systems provides a radiocarbon-depleted tracer for delineating ground-water transport and mixing processes and provides a means of assessing regional magmatic carbon fluxes. Variations in the stable carbon isotopic composition ({delta}{sup 13}C) and carbon-14 values of springs and surface waters from the southern Cascade Range show consistent patterns of carbon isotopic mixing between magmatic, biogenic, and atmospheric CO{sub 2} reservoirs. Radiocarbon measurements of waters from the Lassen region in northern California were used to construct a ground-water carbon-14 contour map, revealing principal subsurface flow paths and a broad region of diffuse magmatic CO{sub 2} flux. 20 refs., 4 figs., 1 tab.

  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. Stalagmite Based Reconstruction of Atmospheric Radiocarbon Levels during Deglaciation: Implications for Radiocarbon Calibration

    NASA Astrophysics Data System (ADS)

    Glynn, S.; Southon, J.; Sinha, A.

    2006-12-01

    Radiocarbon measurements on dendrochronologically dated tree rings provide the most definitive record of atmospheric changes in radiocarbon concentration (14C). However, the tree ring portion of the current radiocarbon calibration curve (INTCAL04) only extends to 12.4 thousand years Before Present (kyr BP). Efforts to extend radiocarbon calibration timescale beyond 12.4 kyr BP have focused on using 14C measurements in marine varves, lake sediments, corals, and a floating tree ring sequence, but significant disagreements exist among these marine and terrestrial 14C data sets. Speleothems (e.g., stalagmites), which are secondary calcite deposits, form by slow degassing of CO2 enriched cave waters, and can be used to generate records of past atmospheric 14C concentration. Furthermore, stalagmites can be precisely dated by U-Th, and the stable isotopic composition of carbon and oxygen in stalagmites offer an opportunity to assess the atmospheric 14C variations in terms of regional climate change. However, a necessary pre-requisite in using stalagmites for radiocarbon calibration purposes is to quantify the dead carbon fraction or DCF. The DCF is the fraction of `old'14C-free carbon derived from host limestone rocks that is incorporated in a given stalagmite, and must be corrected for in order to extract a true atmospheric 14C record. Here, we present results of Accelerator Mass Spectrometry (AMS) 14C measurements in a stalagmite recovered from Timta cave in the western Himalayas in India. The absolute ages of this stalagmite are constrained by 24 230Th dates, which show that it grew from 14.5 to 11.5 kyr BP. The comparison between stalagmite 14C ages with the atmospheric 14C values from the tree ring portion of INTCAL 04 curve (11.5 to 12.4 kyr B.P.) suggest a small but variable DCF that ranges from 2% to 6%. We observe a surprisingly strong inverse correlation between δ13C, a proxy for vegetation changes overlying the cave, and the DCF, perhaps due to pH changes in

  9. Regional and neighborhood disparities in the odds of type 2 diabetes: results from 5 population-based studies in Germany (DIAB-CORE consortium).

    PubMed

    Müller, Grit; Kluttig, Alexander; Greiser, Karin Halina; Moebus, Susanne; Slomiany, Uta; Schipf, Sabine; Völzke, Henry; Maier, Werner; Meisinger, Christa; Tamayo, Teresa; Rathmann, Wolfgang; Berger, Klaus

    2013-07-15

    The objective of this study was to investigate the association between residential environment and type 2 diabetes. We pooled cross-sectional data from 5 population-based German studies (1997-2006): the Cardiovascular Disease, Living and Ageing in Halle Study, the Dortmund Health Study, the Heinz Nixdorf Recall Study, the Cooperative Health Research in the Region of Augsburg Study, and the Study of Health in Pomerania. The outcome of interest was the presence of self-reported type 2 diabetes. We conducted mixed logistic regression models in a hierarchical data set with 8,879 individuals aged 45-74 years on level 1; 226 neighborhoods on level 2; and 5 study regions on level 3. The analyses were adjusted for age, sex, social class, and employment status. The odds ratio for type 2 diabetes was highest in eastern Germany (odds ratio = 1.98, 95% confidence interval: 1.81, 2.14) and northeastern Germany (odds ratio = 1.58, 95% confidence interval: 1.40, 1.77) and lowest in southern Germany (reference) after adjustment for individual variables. Neighborhood unemployment rates explained a large proportion of regional differences. Individuals residing in neighborhoods with high unemployment rates had elevated odds of type 2 diabetes (odds ratio = 1.62, 95% confidence interval: 1.25, 2.09). The diverging levels of unemployment in neighborhoods and regions are an independent source of disparities in type 2 diabetes. PMID:23648804

  10. 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.

  11. 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.

  12. Some archaeologic applications of accelerator radiocarbon analysis

    NASA Astrophysics Data System (ADS)

    Donahue, D. J.; Jull, A. J. T.; Linick, T. W.

    1990-01-01

    The method of preparation of archaeologic samples for AMS radiocarbon dating, the precision of such measurements and the conversion of radiocarbon results to calendar ages are presented. The application of the technique to measurements of the ages of bones, textiles (including the Shroud of Turin), cultigens and other achaeologic artifacts is described.

  13. 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.

  14. 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

  15. 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

  16. Mental Health Disparities

    PubMed Central

    Mays, Robert A.; Huang, Larke Nahme; McCuan, Ron; Pham, Phuong Kim; Fisher, Sylvia Kay; McDuffie, Kathleen Y.; Trachtenberg, Alan

    2009-01-01

    Mental health disparities have received increased attention in the literature in recent years. After considering 165 different health disparity conditions, the Federal Collaborative for Health Disparities Research chose mental health disparity as one of four topics warranting its immediate national research attention. In this essay, we describe the challenges and opportunities encountered in developing a research agenda to address mental health disparities in the United States. Varying definitions of mental health disparity, the heterogeneity of populations facing such disparity, and the power, complexity, and intertwined nature of contributing factors are among the many challenges. We convey an evolving interagency approach to mental health disparities research and guidance for further work in the field. PMID:19820213

  17. Cancer Health Disparities

    Cancer.gov

    Basic information about cancer health 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.

  18. Radiocarbon dating of terrestrial carbonates

    USGS Publications Warehouse

    Pigati, Jeffrey S.

    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.

  19. [How should health and healthcare priorities be set and evaluated? Prioritization methods and regional disparities. 2008 SESPAS Report].

    PubMed

    Sánchez Martínez, Fernando I; Abellán Perpiñán, José María; Martínez Pérez, Jorge E

    2008-04-01

    The conflict between scarce resources and unlimited needs is perhaps more prominent in the healthcare sector than in any other areas. Thus, setting priorities in health care emerges as an unavoidable task. The laudable aim of adopting any health technology that improves the population's health is impossible when confronted by budgetary constraints. Therefore, the outstanding health problems of a society and the most efficient health technologies in terms of their cost-effectiveness must be identified and patients must be prioritized, bearing in mind aspects of equity and efficiency. The present article reviews the issue of setting health care priorities by examining the experiences that have been put into practice in Spain and abroad. The problem is analyzed at three levels: the "macro" level (strategic planning, identification of higher priority areas and the selection of health care interventions); the "meso" level (incorporation of cost-effectiveness analyses into clinical practice guidelines), and the "micro" level (how to design priority systems for patients on waiting lists based on clinical and social criteria). In all these levels, there is substantial heterogeneity between Spanish regional health services, the steps that need to be taken and the ground that needs to be covered. Thus, we suggest that the first steps that some regional health services have made, together with international initiatives, could serve as a reference for the definitive incorporation of new approaches in priority setting in the Spanish health system as a whole. PMID:18405562

  20. 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

  1. Content- and disparity-adaptive stereoscopic image retargeting

    NASA Astrophysics Data System (ADS)

    Yan, Weiqing; Hou, Chunping; Zhou, Yuan; Xiang, Wei

    2016-02-01

    The paper proposes a content- and disparity-adaptive stereoscopic image retargeting. To simultaneously avoid the saliency content and disparity distortion, firstly, we calculate the image saliency region distortion difference, and conclude the factors causing visual distortion. Then, the proposed method via a convex quadratic programming can simultaneously avoid the distortion of the salient region and adjust disparity to a target area, by considering the relationship of the scaling factor of salient region and the disparity scaling factor. The experimental results show that the proposed method is able to successfully adapt the image disparity to the target display screen, while the salient objects remain undistorted in the retargeted stereoscopic image.

  2. 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.

  3. 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

  4. The glacial mid-depth radiocarbon bulge and its implications for the overturning circulation

    NASA Astrophysics Data System (ADS)

    Burke, Andrea; Stewart, Andrew L.; Adkins, Jess F.; Ferrari, Raffaele; Jansen, Malte F.; Thompson, Andrew F.

    2015-07-01

    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 results in a relatively homogenous radiocarbon profile. 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. This shoaled boundary lay above major topographic features associated with strong diapycnal mixing, isolating 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, 2-D, 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 find that a 600 km (~5° of latitude) increase in sea ice extent shoals the boundary between the upper and lower branches of the overturning circulation at 45°S by 600 m and shoals the depth of North Atlantic Deep Water convection at 50°N by 2500 m. This change in circulation configuration alone decreases the radiocarbon content in the mid-depth South Atlantic at 45°S by 40‰, even without an increase in surface radiocarbon age in the source region of deep waters during the LGM.

  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. Disparity estimation and disparity-coherent watermarking

    NASA Astrophysics Data System (ADS)

    Sheikh Faridul, Hasan; Doërr, Gwenaël.; Baudry, Séverine

    2015-03-01

    In the context of stereo video, disparity-coherent watermarking has been introduced to provide superior robustness against virtual view synthesis, as well as to improve perceived fidelity. Still, a number of practical considerations have been overlooked and in particular the role of the underlying depth estimation tool on performances. In this article, we explore the interplay between various stereo video processing primitives and highlight a few take away lessons that should be accounted for to improve performances of future disparity-coherent watermarking systems. In particular, we highlight how lost correspondences during the stereo warping process impact watermark detection, thereby calling for innovative designs.

  7. The Potential for an Independent Source of Younger Dryas Tree-Ring Radiocarbon Data from the Lake Ontario Region, NE North America, and its Paleoenvironmental Context: a Preliminary Report

    NASA Astrophysics Data System (ADS)

    Griggs, C. B.; Southon, J. R.; Kromer, B.; Hogg, A.; Peteet, D. M.; Grote, T.; Cathles, L. M.; Lorentzen, B. E.; Kocik, C.; Kachuck, S.

    2015-12-01

    Tree rings are the gold standard for the calibration of radiocarbon dates into calendar years with limited error due to their annual record of radiocarbon content in the atmosphere. Currently, the tree-ring 14C data used in the International Radiocarbon Calibration curve (IntCal13) are from multiple sources back to ~ 10 ka cal BP for the northern hemisphere. However, the source for tree-ring calibration data prior to ~10 ka cal BP, including the Younger Dryas (YD) and most of the Early Holocene (EH) chronozones, is limited to central Europe. Substantial quantities of logs found in the lowlands of Lake Ontario in North America, dating from 12.1 to 11.2 ka cal BP, have great potential for providing unique YD-EH tree-ring 14C data from a new, previously unrepresented, geographic location and for adding a new perspective to ongoing debates such as the timing of the YD/EH transition in continental North America. Preliminary fieldwork yielded over 43 logs, predominantly spruce (Picea spp.), found buried in alluvial strata over 0.2 hectares of the floodplain at Bell Creek near Fulton, NY. Dendrochronological analysis of 32 spruce logs from this collection has produced several chronologies, one 183 years in length and a second of 147 years with a possible crossdate yielding a chronology of 260 years. Ongoing survey of the site suggests that there is high preservation potential in the same stratigraphic units in an additional ~2 hectares of floodplain, and sample collection with subsequent analysis will increase the chronology's sample depth, extend its length, and potentially provide a robust, independent Younger Dryas - Early Holocene 14C record. Initial assessments of climatic, hydrological, environmental, and isostatic variations and events over time from the tree rings and their stable isotopes, as well as pollen, macrofossil, and sediment analyses and isostatic modeling indicate substantial changes in the Bell Creek Valley and surrounding lowlands both during the YD

  8. 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

  9. 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.

  10. Impact of the Bohunice Nuclear Power Plant on atmospheric radiocarbon.

    PubMed

    Povinec, P P; Sivo, A; Simon, J; Holý, K; Chudý, M; Richtáriková, M; Morávek, J

    2008-11-01

    Radiocarbon variations in the atmospheric CO(2) have been observed at two localities in Slovakia (Bratislava and Zlkovce). Zlkovce is situated about 60 km NE from Bratislava, and only 5 km from the Bohunice Nuclear Power Plant (NPP). The observed Delta(14)C levels provide a unique evidence of the long-term impact of the Bohunice NPP on the Bratislava region, as well as on the decreased fossil fuel CO(2) emissions. The radiation doses estimated to the local public have been around 3 microSv/year, 20% of the dose from global fallout (14)C present in the environment. PMID:18534859

  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. 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.

  13. 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…

  14. Rural Health Disparities

    MedlinePlus

    ... outcomes; quality; and cost, use, and access. AHRQ publishes an annual National Healthcare Disparities Report that summarizes ... is supported by the Health Resources and Services Administration (HRSA) of the U.S. Department of Health and ...

  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. 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. PMID:16078557

  17. 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.

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

    PubMed

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

    2016-06-01

    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

  19. 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

  20. Dynamic neural mechanisms underlie race disparities in social cognition.

    PubMed

    Cassidy, Brittany S; Krendl, Anne C

    2016-05-15

    Race disparities in behavior may emerge in several ways, some of which may be independent of implicit bias. To mitigate the pernicious effects of different race disparities for racial minorities, we must understand whether they are rooted in perceptual, affective, or cognitive processing with regard to race perception. We used fMRI to disentangle dynamic neural mechanisms predictive of two separable race disparities that can be obtained from a trustworthiness ratings task. Increased coupling between regions involved in perceptual and affective processing when viewing Black versus White faces predicted less later racial trust disparity, which was related to implicit bias. In contrast, increased functional coupling between regions involved in controlled processing predicted less later disparity in the differentiation of Black versus White faces with regard to perceived trust, which was unrelated to bias. These findings reveal that distinct neural signatures underlie separable race disparities in social cognition that may or may not be related to implicit bias. PMID:26908320

  1. 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.

  2. Mechanisms for similarity matching in disparity measurement

    PubMed Central

    Goutcher, Ross; Hibbard, Paul B.

    2014-01-01

    Early neural mechanisms for the measurement of binocular disparity appear to operate in a manner consistent with cross-correlation-like processes. Consequently, cross-correlation, or cross-correlation-like procedures have been used in a range of models of disparity measurement. Using such procedures as the basis for disparity measurement creates a preference for correspondence solutions that maximize the similarity between local left and right eye image regions. Here, we examine how observers’ perception of depth in an ambiguous stereogram is affected by manipulations of luminance and orientation-based image similarity. Results show a strong effect of coarse-scale luminance similarity manipulations, but a relatively weak effect of finer-scale manipulations of orientation similarity. This is in contrast to the measurements of depth obtained from a standard cross-correlation model. This model shows strong effects of orientation similarity manipulations and weaker effects of luminance similarity. In order to account for these discrepancies, the standard cross-correlation approach may be modified to include an initial spatial frequency filtering stage. The performance of this adjusted model most closely matches human psychophysical data when spatial frequency filtering favors coarser scales. This is consistent with the operation of disparity measurement processes where spatial frequency and disparity tuning are correlated, or where disparity measurement operates in a coarse-to-fine manner. PMID:24409163

  3. 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.

  4. Radiocarbon age differences between coexisting foraminiferal species

    NASA Astrophysics Data System (ADS)

    Broecker, Wallace; Matsumoto, Katsumi; Clark, Elizabeth; Hajdas, Irka; Bonani, Georges

    1999-08-01

    Radiocarbon-age measurements on single species of foraminifera from a core on the Ceara Rise demonstrate the importance of the joint effect of bioturbation and variable rain abundance of foraminifera. The relatively high mixed layer ages for Pulleniatina obliquiloculata reflect, at least in part, an early Holocene peak in its abundance while the relatively young ages for Globorotalia menardii reflect the delay until mid Holocene of its reappearance in the Atlantic Ocean. These results clearly demonstrate that core-top sediment samples need not be representative foraminifera falling from today's surface ocean. Rather, at least on the Ceara Rise, such samples consist of a composite of changing species groupings. These results also reconfirm the pitfalls associated with attempts to reconstruct the radiocarbon age of deep ocean water on the basis of benthic-planktonic foraminiferal age differences.

  5. Radiocarbon dating in groundwater systems: Chapter 4

    USGS Publications Warehouse

    Plummer, L.N.; Glynn, P.D.

    2013-01-01

    The radioactive isotope of carbon, radiocarbon (14C), was first produced artificially in 1940 by Martin Kamen and Sam Ruben, who bombarded graphite in a cyclotron at the Radiation Laboratory at Berkeley, CA, in an attempt to produce a radioactive isotope of carbon that could be used as a tracer in biological systems (Kamen (1963) [101]; Ruben and Kamen (1941) [102]). Carbon-14 of cosmogenic origin was discovered in atmospheric CO2 in 1946 by Willard F. Libby, who determined a half-life of 5568 a. Libby and his co-workers (Anderson et al. (1947) [103]; Libby et al. (1949) [104]) developed radiocarbon dating of organic carbon of biological origin, which revolutionized research in a number of fields, including archaeology and quaternary geology/climatology, by establishing ages and chronologies of events that have occurred over the past approximately 45 ka.

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

    USGS Publications Warehouse

    Stafford, Thomas W., Jr.; Jull, A.J.T.; Zabel, T.H.; Donahue, D.J.; Duhamel, R.C.; Brendel, K.; Haynes, C.V., Jr.; 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.

  7. Radiocarbon in Tree STEM CO2 Efflux

    NASA Astrophysics Data System (ADS)

    Muhr, J.; Czimczik, C. I.; Angert, A.; Trumbore, S.

    2011-12-01

    Carbon dioxide efflux from tree stems can be a significant component of the stand-level carbon balance. Recent studies have demonstrated that tree stem CO2 efflux may reflect more than just in-situ respiration but also transport from other locations and it has been suggested that it may also include C originally respired in roots or even uptake of soil CO2. We report measurements of the radiocarbon signature of carbon emitted from a range of mature tree stems in tropical and temperate forest ecosystems. Comparison of the radiocarbon signature of respired CO2 with the observed rate of decline in atmsopheric 14C-CO2 provides a measure of the time elapsed between C fixation by the plant and its return to the atmosphere as stem CO2 efflux. In all investigated trees, we observed that stem CO2 efflux had higher radiocarbon signatures than the contemporary atmospheric 14C-CO2, and therefore was derived from C fixed one to several years earlier. In tropical forest trees, we found that the 14C signature of CO2 within the stem (~4-5 cm depth) had even higher radiocarbon signatures than the stem CO2 efflux. In one of the investigated tree species, the in-stem CO2 was derived from C sources fixed on average ~20 years previously. These results confirm observations of root-respired CO2 that also have shown contributions of C substrates older than recent photosynthetic products, and the presence of extracable C reserves in wood that reflect the presence of older C sources. Our results imply that stem CO2 efflux is not only derived from respiration of recent photosynthetic products but includes contributions from older, stored C pools. Ongoing investigations will enable us to compare CO2 efflux for trees subjected to experimental drought, and using different life strategies (deciduous versus evergreen oaks) to determine if the use of these older C stores varies with stress.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Cardiovascular Health Disparities

    PubMed Central

    Davis, Andrew M.; Vinci, Lisa M.; Okwuosa, Tochi M.; Chase, Ayana R.; Huang, Elbert S.

    2008-01-01

    Racial and ethnic disparities in cardiovascular health care are well documented. Promising approaches to disparity reduction are increasingly described in literature published since 1995, but reports are fragmented by risk, condition, population, and setting. The authors conducted a systematic review of clinically oriented studies in communities of color that addressed hypertension, hyperlipidemia, physical inactivity, tobacco, and two major cardiovascular conditions, coronary artery disease and heart failure. Virtually no literature specifically addressed disparity reduction. The greatest focus has been African American populations, with relatively little work in Hispanic, Asian, and Native American populations. The authors found 62 interventions, 27 addressing hypertension, 9 lipids, 18 tobacco use, 8 physical inactivity, and 7 heart failure. Only 1 study specifically addressed postmyocardial infarction care. Data supporting the value of registries, multidisciplinary teams, and community outreach were found across several conditions. Interventions addressing care transitions, using telephonic outreach, and promoting medication access and adherence merit further exploration. PMID:17881625

  13. 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.

  14. 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.

  15. Minority Health and Health Disparities

    MedlinePlus

    ... Minority Health and Health Disparities Certain ethnic and racial minorities as well as other underserved populations experience ... disorders than do non-Hispanic whites, ethnic and racial disparities still exist for alcohol-related diseases, problems, ...

  16. 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. PMID:27405647

  17. 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

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

    PubMed

    Graven, Heather D

    2015-08-01

    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 ((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. PMID:26195757

  19. 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

  20. Radiocarbon dating: Jewish inspiration of Christian catacombs

    NASA Astrophysics Data System (ADS)

    Rutgers, Leonard V.; van der Borg, Klaas; de Jong, Arie F. M.; Poole, Imogen

    2005-07-01

    The famous catacombs of ancient Rome are huge underground cemeteries, of which two Jewish catacomb complexes of uncertain age and 60 early-Christian catacombs have survived. Here we use radiocarbon dating to determine the age of wood originating from one of the Jewish catacombs and find that it pre-dates its Christian counterparts by at least 100 years. These results indicate that burial in Roman catacombs may not have begun as a strictly Christian practice, as is commonly believed, but rather that its origin may lie in Jewish funerary customs.

  1. Radiocarbon dating and archeology in North America.

    PubMed

    Johnson, F

    1967-01-13

    The history of the development of a radiocarbon chronology shows how the establishment of the times of events and the order of them has greatly improved the understanding of prehistory in North America. This is true also of other parts of the world. Too little has been said of existing discordance between archeologically determined sequences, and interregional associations, and the radiocarbon chronology. It does appear that these will be resolved as additional dates are added and as the results become more finely calibrated so that secular variations may be accounted for. The collaborative aspect of the venture was apparent at the outset. Nevertheless no one expects an archeologist to delve into nuclear physics and geochemistry, and vice versa. There is great need, nevertheless, for the man in the laboratory to comprehend the difficulties of sample collecting and of judgement of the significance of the source of organic matter to be dated. At the same time, the archeologist must become more familiar with the importance of the various steps in the processing of the sample and with, what is most vital, interpretation of the significance of the numbers that appear on the counters. PMID:6015523

  2. 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.

  3. 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

  4. 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

  5. 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. PMID:26704325

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. Differential extraction of radiocarbon associated with soil biomass and humus

    SciTech Connect

    Tsao, C.W.; Bartha, R. . Cook Coll.)

    1999-04-01

    To detect the humification of organic compounds in soil that bypasses biomass incorporation, selective extraction procedures for radiocarbon from soil biomass and humus were evaluated. Following the incubation of [sup 14]C-glucose and [sup 14]C-benzoate in soil, fumigation--0.5 M K[sub 2]SO[sub 4] extraction and 0.15 M Na[sub 4]P[sub 2]O[sub 7] extraction selectively removed biomass-associated and humus-associated radiocarbon, respectively. Applying the recovery correction of 3.4[times] to biomass and 3.5[times] to humus, radiocarbon balances of 95 to 107% were obtained during a time window following the degradation of these substrates. Negligible overlap between the extractions renders the technique suitable for investigating the fate of organics that, through cometabolism, attain unusual radiocarbon distributions in soil.

  13. Proposal of a new Concept using Hydrogeological Classification to Overcome the Disparity of Local Observations and the Demand for Regional Scale Groundwater Assessment

    NASA Astrophysics Data System (ADS)

    Barthel, R.; Bendel, D.; Bardossy, A.; Samaniego, L. E.; Kumar, R.

    2012-12-01

    A new concept is proposed for the assessment of groundwater systems (quantity and quality) on the regional scale as an analogue to the concepts of Catchment Classification and Hydrologic Similarity developed in surface water hydrology within the framework of PUB (Predictions in Ungauged Basins). While groundwater models rely primarily on local data which is not always available for all parts of large river basins, the proposed approach strives to statistically derive relevant information for unobserved areas, making use of existing information from observed locations. The proposed concept is based on the hypothesis that similar groundwater systems respond similarly to similar impacts. At its core is the classification of (i) static hydrogeological characteristics (such as aquifer geometry and hydraulic properties and well design), (ii) dynamic changes of the boundary conditions (such as recharge, withdrawal, changes of water levels in connected surface water bodies), and (iii) dynamic groundwater system responses (time series of groundwater head and chemical parameters), as well as the systematic use of the dependencies of system responses on explanatory variables. The latter would be for example encompassing the dependencies between groundwater heads and various chemical parameters, which are in turn dependent on the static hydrogeological characteristics and dynamic system changes. Classification of static and dynamic system features combined with information about known system properties and their dependencies provide insight into system behaviour that cannot be directly derived through the analysis of unclassified data. The proposed methodology could (i) allow the prediction of missing data values in space and time, (ii) support the determination of dominant processes on different scales, (iii) give better insights in cause and effect relationships related to environmental change, and (iv) provide a pragmatic tool to bridge the gap between local observations

  14. 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.

  15. Predicted net efflux of radiocarbon from the ocean and increase in atmospheric radiocarbon content

    NASA Astrophysics Data System (ADS)

    Caldeira, Ken; Rau, Greg H.; Duffy, Philip B.

    Prior to changes introduced by man, production of radiocarbon (14C) in the stratosphere nearly balanced the flux of 14C from the atmosphere to the ocean and land biosphere, which in turn nearly balanced radioactive decay in these 14C reservoirs. This balance has been altered by land-use changes, fossil-fuel burning, and atmospheric nuclear detonations. Here, we use a model of the global carbon cycle to quantify these radiocarbon fluxes and make predictions about their magnitude in the future. Atmospheric nuclear detonations increased atmospheric 14C content by about 80% by the mid-1960's. Since that time, the 14C content of the atmosphere has been diminishing as this bomb radiocarbon has been entering the oceans and terrestrial biosphere. However, we predict that atmospheric 14C content will reach a minimum and start to increase within the next few years if fossil-fuel burning continues according to a “business-as-usual” scenario, even though fossil fuels are devoid of 14C. This will happen because fossil-fuel carbon diminishes the net flux of 14C from the atmosphere to the oceans and land biosphere, forcing 14C to accumulate in the atmosphere. Furthermore, the net flux of both bomb and natural 14C into the ocean are predicted to continue to slow and then, in the middle of the next century, to reverse, so that there will be a net flux of 14C from the ocean to the atmosphere. The predicted reversal of net 14C fluxes into the ocean is a further example of human impacts on the global carbon cycle.

  16. Accelerator radiocarbon dating: new applications and capabilities

    SciTech Connect

    Cresswell, R.G.; Beukens, R.P.; Lee, H.W.

    1985-01-01

    As with new advances in any field, radiocarbon dating by accelerator mass spectrometry has to be treated with some scepticism until it has proven itself against the conventional techniques. By the direct atom counting of the radioactive carbon isotope, C-14, rather than the counting of the beta particles, any background is eliminated and microgram-sized samples of a solid graphite-like target can be analyzed in a few hours instead of many days. The IsoTrace laboratory has completed a comparative analysis with materials dated by the conventional method and has shown excellent agreement, yielding an accuracy better than 1% and a precision of 0.3%. For samples less than 10,000 years old, a precision of 1.0% is routinely obtained, while, for samples less than 2000 years old, precision of 0.3% is possible. Dates can also be routinely obtained from materials up to 50,000 years old. With the small sample size and high precision, greater resolution when dating recent materials may be obtained. Materials that previously proved impossible to date due to small sample size or the nature of the material (e.g. high value, weathering etc.) may now readily be subjected to scrutiny. Fragments, rather than bulk samples, may be dated, facilitating significant stratigraphic resolution and correlation in a wide variety of situations.

  17. 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.

  18. 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.

  19. 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. PMID:18955702

  20. 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

  1. Bolivia survey reveals disparities.

    PubMed

    1999-01-01

    Findings from the Bolivia Demographic and Health Survey in 1998 indicate that large fertility and reproductive health disparities based on education level and geographic location still persist in the country. Despite substantial improvement in the overall education level of Bolivian women in the past 5 years, urban women are almost 5 times more likely to attend high school than rural women are. Major differences in education level also exist between provinces. Total fertility rate is at 4.2 children per woman, with women without education having more than 3 times the number of children compared to those with higher education. At such rates, rural women will have an average of 6.3 children, which are 2.5 children more than their urban counterparts. Moreover, nearly 80% of women in union know of a modern method of contraception and 45% of them are using some form of family planning. The highest levels of contraceptive use are among women with higher education and women in urban areas. There is also a notable increase in the number of women who receive assistance from a trained medical professional during delivery. Infant and child mortality rates remain among the highest in Latin America although both rates have declined since the 1994 survey findings. Infant mortality rates are still 80% higher in rural areas than urban areas. PMID:12349605

  2. Disability disparities: a beginning model.

    PubMed

    Lewis, Allen

    2009-01-01

    This paper presents a model of disability disparities. Though the concept of health disparities is discussed in the health care literature, there is no such model that explicitly addresses disparities in the disability literature. Therefore, this model begins to fill a void in the disability literature. Part of the value of such a model is that it represents an attempt to address the question of why cultural competency is important in the disability arena at this point in the 21st century. The urgency in addressing cultural competency at this time in history is supported by understanding the multiple accountability demands on rehabilitation and disability providers these days, e.g., increasing diversification of the United States population, that render providing effective services to everyone a clear mandate. The author provides a working definition of disability disparity. The disability disparity model is described in terms of its five-domain continuum as well as its macro- and micro-level aspects that are designed to both promote clarity of the concept for researchers and offer practitioners ideas on how to explore the existence of disability disparities in working with specific service recipients. Limitations and strengths of the model are discussed along with suggested next steps in model validation. PMID:19802930

  3. The Bad Law of "Disparate Impact."

    ERIC Educational Resources Information Center

    Clegg, Roger

    2000-01-01

    Describes the disparate impact theory of discrimination, noting how its effect was recently on display in two high profile cases. Discusses the recent explosion of disparate impact lawsuits related to employment and education; examines why the disparate impact approach survives and thrives; explains the intent of disparate impact theory; and…

  4. Addressing Geographic Disparities in Liver Transplantation through Redistricting

    PubMed Central

    Gentry, Sommer E.; Massie, Allan B.; Cheek, Sidney W.; Lentine, Krista L.; Chow, Eric K. H.; Wickliffe, Corey E.; Dzebashvili, Nino; Salvalaggio, Paolo R.; Schnitzler, Mark A.; Axelrod, David A.; Segev, Dorry L.

    2015-01-01

    Severe geographic disparities exist in liver transplantation; for patients with comparable disease severity, 90-day transplant rates range from 18%–86% and death rates range from 14%–82% across donor service areas (DSAs). Broader sharing has been proposed to resolve geographic inequity; however, we hypothesized that the efficacy of broader sharing depends on the geographic partitions used. To determine the potential impact of redistricting on geographic disparity in disease severity at transplantation, we combined existing DSAs into novel regions using mathematical redistricting optimization. Optimized maps and current maps were evaluated using the Liver Simulated Allocation Model. Primary analysis was based on 6700 deceased donors, 28,063 liver transplant candidates, and 242,727 Model of End-Stage Liver Disease (MELD) changes in 2010. Fully regional sharing within the current regional map would paradoxically worsen geographic disparity (variance in MELD at transplantation increases from 11.2 to 13.5, p=0.021), although it would decrease waitlist deaths (from 1368 to 1329, p=0.002). In contrast, regional sharing within an optimized map would significantly reduce geographic disparity (to 7.0, p=0.002) while achieving a larger decrease in waitlist deaths (to 1307, p=0.002). Redistricting optimization, but not broader sharing alone, would reduce geographic disparity in allocation of livers for transplant across the United States. PMID:23837931

  5. 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. PMID:25788477

  6. Very long solar periods and the radiocarbon record

    NASA Technical Reports Server (NTRS)

    Sonett, C. P.

    1984-01-01

    It is pointed out that radiocarbon is produced in the earth's atmosphere by the nuclear reaction N-14(n,p)C-14. The photosynthesis by trees of carbon in the form of CO2 provides an estimate of the C-14/C-12 ratio and, therefore, the atmospheric inventory of C-14 at the time of take-up. The existence of periodicities in the radiocarbon record has been considered by Suess (1965, 1971, 1980). The present investigation is concerned with these periodicities. Periodicities in the radiocarbon record are related to variability in the modulation of the galactic component of the incoming cosmic ray flux, mediated by the oceanic and atmospheric reservoirs. The long periods observed are an indicator of corresponding changes in the hydromagnetic output of the sun, which might be caused by changes in the intensity of the magnetic field escaping from the solar atmosphere.

  7. Radiocarbon age distribution of groundwater in the Konya Closed Basin, central Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Bayari, C. Serdar; Ozyurt, N. Nur; Kilani, Susan

    2009-03-01

    Annual abstraction of 2.6 × 109 m3 of groundwater in the 53,000 km2 Konya Closed Basin of central Turkey has caused a head decline of 1 m/year over the last few decades. Therefore, understanding the hydrogeology of this large endorheic basin, in a semi-arid climate, is important to sustainable resource management. For this purpose, the groundwater’s radiocarbon age distribution has been investigated along a 150-km transect parallel to regional flow. Results show that the groundwater ranges in age from Recent at the main recharge area of the Taurus Mountains in the south, to about 40,000 years around the terminal Salt Lake located in the north. In this predominantly confined flow system, radiocarbon ages increase linearly by distance from the main recharge area and are in agreement with the hydraulic ages. The mean velocity of regional groundwater flow (3 m/year) is determined by the rate of regional groundwater discharge into the Salt Lake. Calcite dissolution, dedolomitization and geogenic carbon dioxide influx appear to be the dominant geochemical processes that determine the carbon isotope composition along the regional flow path. The groundwater’s oxygen-18 content indicates more humid and cooler paleorecharge. A maximum drop of 5°C is inferred for the past recharge temperature.

  8. 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. PMID:11729315

  9. 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.

  10. Fast perception of binocular disparity.

    PubMed

    Caziot, Baptiste; Valsecchi, Matteo; Gegenfurtner, Karl R; Backus, Benjamin T

    2015-08-01

    Is depth perception from binocular disparities-stereopsis-slow or fast? Many of the temporal properties of stereopsis are known. For example, rapidly changing disparities are perceptually difficult to track, which suggests that stereopsis is generally slow. But, remarkably, this basic question has not yet been addressed. We compared speed-accuracy trade-off functions between 2 forced-choice discriminations: 1 based on stereoscopic depth and 1 based on luminance. Unexpectedly, both speed-accuracy trade-off functions deviated from chance levels of accuracy at the same response time-approximately 200 ms-with stereo accuracy increasing, on average, more slowly than luminance accuracy after this initial delay. Thus, the initial processing of disparity for perceived depth took no longer than the initial processing of luminance for perceived brightness. This finding, that binocular disparities are available early during visual processing, means that depth is perceived quickly, and, intriguingly, that disparities may be more important for everyday visual function than previously thought. PMID:26121497

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. 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.

  13. 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.

  14. 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

  15. 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. PMID:26488413

  16. 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

  17. 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

  18. 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

  19. 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...

  20. 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.

  1. 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.

  2. 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. ...

  3. DEVELOPMENT & APPLICATION OF RADIOCARBON (14C)/ORGANIC DENUDER METHODS

    EPA Science Inventory

    The radiocarbon (14C) content of a sample measures the fraction of the sample's carbon originating from non-fossil-fuel (biogenic) sources. The most important of these sources are biomass burning (mostly winter, but wildfires can contribute in other seasons as well) and secondar...

  4. 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…

  5. 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…

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

    PubMed Central

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

    2011-01-01

    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. PMID:21187404

  7. 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.

  8. 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

  9. 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. PMID:25815508

  10. 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…

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 29 CFR 1607.11 - Disparate treatment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 4 2012-07-01 2012-07-01 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...

  16. 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

  17. 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

  18. A micro-architecture for binocular disparity and ocular dominance in visual cortex.

    PubMed

    Kara, Prakash; Boyd, Jamie D

    2009-04-01

    In invertebrate predators such as the praying mantis and vertebrate predators such as wild cats the ability to detect small differences in inter-ocular retinal disparities is a critical means for accurately determining the depth of moving objects such as prey. In mammals, the first neurons along the visual pathway that encode binocular disparities are found in the visual cortex. However, a precise functional architecture for binocular disparity has never been demonstrated in any species, and coarse maps for disparity have been found in only one primate species. Moreover, the dominant approach for assaying the developmental plasticity of binocular cortical neurons used monocular tests of ocular dominance to infer binocular function. The few studies that examined the relationship between ocular dominance and binocular disparity of individual cells used single-unit recordings and have provided conflicting results regarding whether ocular dominance can predict the selectivity or sensitivity to binocular disparity. We used two-photon calcium imaging to sample the response to monocular and binocular visual stimuli from nearly every adjacent neuron in a small region of the cat visual cortex, area 18. Here we show that local circuits for ocular dominance always have smooth and graded transitions from one apparently monocular functional domain to an adjacent binocular region. Most unexpectedly, we discovered a new map in the cat visual cortex that had a precise functional micro-architecture for binocular disparity selectivity. At the level of single cells, ocular dominance was unrelated to binocular disparity selectivity or sensitivity. When the local maps for ocular dominance and binocular disparity both had measurable gradients at a given cortical site, the two gradient directions were orthogonal to each other. Together, these results indicate that, from the perspective of the spiking activity of individual neurons, ocular dominance cannot predict binocular disparity

  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. 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.

  1. 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. PMID:26504205

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Radiocarbon ages of Sorori ancient rice of Korea

    NASA Astrophysics Data System (ADS)

    Kim, Kyeong Ja; Lee, Yung-Jo; Woo, Jong-Yoon; Jull, A. J. Timothy

    2013-01-01

    Samples of Sorori ancient rice were excavated in 1998 from the Sorori Paleolithic site located at Sorori, Oksan-myeon, Cheong-won County in Chungcheongbuk-do, Korea. We have made new radiocarbon measurements for Sorori samples in 2009 at the NSF Arizona AMS Laboratory. Both ancient rice samples and surrounded peat from the Sorori site were dated. The AMS results confirmed that the ages of the rice and peat soil were 12,520 ± 150 and 12,552 ± 90 BP, respectively. These radiocarbon ages are consistent with the previously published data of quasi rice measured at Seoul National University and confirm that the Sorori rice is the oldest ancient rice currently reported.

  7. 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.

  8. 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.

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

    PubMed Central

    Buchholz, B.A.; Spalding, K.L

    2010-01-01

    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 (14C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, 14C levels in the enamel represent 14C 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. PMID:20976120

  10. 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.

  11. 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.

  12. 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

  13. 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. PMID:26699457

  14. 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. PMID:20976120

  15. Late Glacial to Holocene radiocarbon constraints on North Pacific Intermediate Water ventilation and deglacial atmospheric CO2 sources

    NASA Astrophysics Data System (ADS)

    Davies-Walczak, Maureen; Mix, A. C.; Stoner, J. S.; Southon, J. R.; Cheseby, M.; Xuan, C.

    2014-07-01

    Radiocarbon reconstructions of past ocean ventilation rates constrain oceanic sources and sinks of CO2 and mechanisms of subsurface hypoxia. Here, 14C in coexisting benthic and planktonic foraminifera from a sediment core 682 m deep off Southeast Alaska documents paleoventilation over the past ∼17,000 years. A chronology based on calibrated planktonic foraminiferal dates, consistent with independent terrestrial dates for regional glacial retreat, yields deglacial projection ages moderately greater than those of the Holocene, suggesting comparatively limited ventilation. The observed Holocene increase of apparent ventilation at intermediate depths tracks inundation of the Bering Strait between ∼11,800 and 13,200 years ago, suggesting that flooding of continental shelves and export of low-salinity surface waters to the Arctic enhanced intermediate water formation in the North Pacific. An abrupt increase in the benthic-planktonic radiocarbon age gradient, implying homogenization of abyssal radiocarbon in deep and intermediate waters, aligns with the younger of two episodes of rapid rise of atmospheric CO2 and depletion of atmospheric ΔC14 during deglaciation (∼11,500-13,000 years ago), suggesting the North Pacific as a possible pathway for venting of oceanic CO2 to the atmosphere during the second half of the deglacial transition.

  16. MEASURING EARLY LIFE DISPARITY IN INDIA.

    PubMed

    Singh, Akansha; Ladusingh, Laishram

    2016-08-01

    Early life disparity - defined as the average life years lost due to death by the age of 60 years - can be used to assess more systematically the effect of savings from death at a young age. In addition, it can give valuable insight into the consequences of death in the early stages of life. Early life disparity can further be categorized into child life disparity (0-14 years) and adult life disparity (15-60 years). This study estimated early life disparity using complete life tables for the period 1970-1975 to 2006-2010, which were constructed from abridged life tables and death rates provided by the Sample Registration System (SRS) in India. The contribution of premature deaths to the difference in life disparity was estimated using a replacement algorithm. The findings clearly indicated an overall declining trend in early life disparity in India, with a notable reduction in child life disparity, and a deceleration of adult life disparity during the period 1970-1975 to 2006-2010. Interstate variations in early life disparity were seen to converge with time. Decomposition analysis suggested that these variations could be minimized further by averting death during childhood. PMID:26537823

  17. 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.

  18. The persistence of American Indian health disparities.

    PubMed

    Jones, David S

    2006-12-01

    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

  19. 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

  20. 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

  1. 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.

  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. 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

  4. 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

  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. PMID:23659676

  6. 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.

  7. 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.

  8. 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

  9. 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…

  10. Radiocarbon Ages of Postglacial Lake Clays near Michigan City, Indiana.

    PubMed

    Winkler, E M

    1962-08-17

    Two radiocarbon dates were obtained for postglacial clays. One sample, 6350 years old, was taken from a bed of compacted and carbonized wood just above a bed of pebbly clay. Overlying the woody bed is 5(1/2) feet of organic bluish clays and beach sands near the present lake level. The upper clay layer contained a younger wood sample, 5475 years old. The blue clays are of shallow swamp origin and were deposited during the late low-water stage of Lake Chippewa; the pebbly clay is assumed to be of Glenwood age (about 11,000 years) or older. PMID:17749630

  11. Micro Radiocarbon Dating - Applications and challenges in Alpine glaciology

    NASA Astrophysics Data System (ADS)

    Hoffmann, Helene; Bohleber, Pascal; Wagenbach, Dietmar

    2015-04-01

    The interpretation of proxy records from ice cores obtained at cold small scale Alpine glaciers is hampered first and foremost because of challenges in obtaining a reliable age scale, especially for highly thinned basal ice. Where conventional stratigraphic dating methods fail, either due to complex flow dynamics or missing layering, radiocarbon measurements of organic impurities are up to now the only option to retrieve absolute age markers. Supplementing stratigraphic records, age of basal ice itself can provide valuable information on paleoclimatic conditions, e.g. related to the onset of formation of the respective ice body. In this respect, potential targets are basal sections of Alpine ice cores and small isolated ice patches or ice caves. Organic material in ice can be separated mainly by size into DOC (Dissolved Organic Carbon) and POC (Particulate Organic Carbon). Here we focus on radiocarbon dating of the POC fraction, because the DOC fraction is known to be biased by in situ production at high Alpine sites. Concentrations of POC in high Alpine ice can be very low, ranging from about 10 µgC per kg ice to 50 µgC per kg ice. This becomes an immediate challenge when sampling ice cores, where available masses for dating are typically in the order of a few hundred grams of ice. After developing an unique sample preparation system we managed to reduce the process blank reproducibly below one microgram carbon, independent of other sample characteristics. Utilizing a gas ion source at the Accelerator Mass Spectrometer MICADAS at the Klaus-Tschira-Lab in Mannheim (Germany) we are now able to reliably date samples with concentrations as low as 10 µg carbon. Accordingly, this approach becomes applicable for high Alpine ice samples. Here we present first results from POC radiocarbon dating of Alpine ice cores along with selected basal ice samples from smaller ice caps and cave ice in order to obtain a broader picture regarding age ranges of Alpine ice bodies. For

  12. 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).

  13. 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…

  14. What limits the morphological disparity of clades?

    PubMed

    Oyston, Jack W; Hughes, Martin; Wagner, Peter J; Gerber, Sylvain; Wills, Matthew A

    2015-12-01

    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

  15. 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…

  16. 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

  17. 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…

  18. Anomalous radiocarbon ages from a Holocene detrital organic lens in Alaska and their implications for radiocarbon dating and paleoenvironmental reconstructions in the arctic

    USGS Publications Warehouse

    Nelson, R.E.; Carter, L.D.; Robinson, S.W.

    1988-01-01

    Eleven radiocarbon age determinations clearly show that a lens of Holocene fluvial organic debris on the Alaskan Arctic Coastal Plain contains mostly pre-Holocene organic material. Radio-carbon ages of identified plant macrofossils indicate the material was deposited about 9000 to 9500 yr B.P. Radiocarbon analyses of bulk samples from this deposit, however, range from 13,300 to 30,300 yr B.P. Most of the old organic matter seems to be in the smaller size fractions in the deposit, particularly in the fraction between 0.25 and 0.5 mm, but all size fractions are contaminated. Particular caution must be exercised in submitting bulk samples for radiocarbon dating from areas where conditions favor redeposition of isotopically "dead" carbon. ?? 1988.

  19. 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

  20. Gender disparity in organ donation.

    PubMed

    Steinman, Judith L

    2006-12-01

    Organ donation is affected by legal, cultural, religious, and racial factors, as well as by health considerations. Although organs in and of themselves are gender neutral and can be exchanged between the sexes, women account for up to two thirds of all organ donations. There are no clear reasons why women are more willing to undergo the risks of surgery than are men, nor is this gender disparity mirrored in the demand for donated organs. More men than women are recipients, and women are less likely to complete the necessary steps to receive donated organs. Internationally, ethical concern has been focused on possible human rights violations in the harvesting of organs from prisoners and, in poor countries, on the trafficking of organs from girls and women who are expected to financially help their families by selling their organs. PMID:17582366

  1. Coral radiocarbon constraints on the source of the Indonesian throughflow

    SciTech Connect

    Moore, M.D.; Schrag, D.P.; Kashgarian, M.

    1997-06-01

    Radiocarbon variability in {ital Porites} spp. corals from Guam and the Makassar Strait (Indonesian Seaway) was used to identify the source waters contributing to the Indonesian throughflow. Time series with bimonthly resolution were constructed using accelerator mass spectrometry. The seasonal variability ranges from 15 to 60{per_thousand}, with large interannual variability. {Delta}{sup 14}C values from Indonesia and Guam have a nearly identical range. Annual mean {Delta}{sup 14}C values from Indonesia are 50 to 60{per_thousand} higher than in corals from Canton in the South Equatorial Current [{ital Druffel}, 1987]. These observations support a year-round North Pacific source for the Indonesian throughflow and imply negligible contribution by South Equatorial Current water. The large seasonality in {Delta}{sup 14}C values from both sites emphasizes the dynamic behavior of radiocarbon in the surface ocean and suggests that {Delta}{sup 14}C time series of similar resolution can help constrain seasonal and interannual changes in ocean circulation in the Pacific over the last several decades.{copyright} 1997 American Geophysical Union

  2. 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.

  3. Evaluation of preparation methods in radiocarbon dating of old wood

    NASA Astrophysics Data System (ADS)

    Hajdas, Irka; Hendriks, Laura; Fontana, Alessandro; Monegato, Giovanni

    2015-04-01

    Radiocarbon analyses require pre-treatment of the material before proceeding with the isotopic analysis, both with counting of decay particles (conventional method) or 14C atoms (AMS method). From the early days of the method the standard treatment involved removal of contamination by washes in acid (carbonates dissolved) and base (humic acid) dissolved (ABA). Modification of this method has been suggested, especially for old material, i.e. older than 20 ka. However the criticism of ABA and application of a more aggressive oxidizing method might be only needed in some special cases, for example of poor preservation (ABOX or separation of cellulose from wood). As a part of studies focusing on chronology of late Pleistocene sedimentary processes in the Venetian-Friulian Plain and Carnic Alps (NE Italy), radiocarbon analyses were performed on old wood samples found in sedimentary deposits of pre-LGM age. Our results show that in most cases ABA method is sufficient to remove the contamination of naturally deposited wood independently of the age of the wood.

  4. Vertebral Bomb Radiocarbon Suggests Extreme Longevity in White Sharks

    PubMed Central

    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 (Δ14C) 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 14C 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. PMID:24416189

  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. PMID:24416189

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Health Disparities and Discrimination: Three Perspectives.

    PubMed

    Ndiaye, Khadidiatou; Krieger, Janice R; Warren, Jennifer R; Hecht, Michael L; Okuyemi, Kola

    2008-10-01

    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

  11. 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.

  12. 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

  13. Quantifying Access Disparities in Response Plans.

    PubMed

    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

  14. Forty years of atmospheric radiocarbon monitoring around Bohunice nuclear power plant, Slovakia.

    PubMed

    Povinec, P P; Chudý, M; Sivo, A; Simon, J; Holý, K; Richtáriková, M

    2009-02-01

    Radiocarbon variations in the atmospheric CO(2) with attenuating amplitudes and decreasing mean values with typical maxima in summer and minima in winter have been observed since 1967 in two localities of Slovakia, in Bratislava and Zlkovce, situated about 60 km NE from Bratislava, only 5 km from the Bohunice Nuclear Power Plant (NPP). The (14)C record in Bratislava has been influenced mainly by fossil CO(2) emissions, in contrast to the Zlkovce record which has been more variable, as it has clearly been affected by operation of the Bohunice NPP. However, during specific meteorological conditions with NE transport of air masses to Bratislava, the effect of the Bohunice NPP has been visible in Bratislava as well. Maximum (14)C concentrations (up to 120% above a natural background) were observed around A1 NPP which used CO(2) with admixture of air as a cooling agent. The (14)C concentrations around four pressurized light water reactors were up to 30% above the background. The Delta(14)C values in the heavily polluted atmosphere of Bratislava were up to 10% and at Zlkovce up to 5% lower than the European clean air represented by the Jungfraujoch Delta(14)C data. Later the Delta(14)C values were similar at both sites, and from 2003 they were close to the European clean air levels. The observed Delta(14)C behaviour in the atmosphere provides a unique evidence of decreased fossil fuel CO(2) emissions in the region, as well as the long-term effect of the Bohunice NPP on the Bratislava and Zlkovce stations. The estimated annual radiation doses to the local public due to digestion of radiocarbon contaminated food have been estimated to be around 3 microSv. PMID:18926606

  15. 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. PMID:24964386

  16. 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.

  17. Economic disparities in treatment costs among ambulatory Medicaid cancer patients.

    PubMed Central

    Mullins, C. Daniel; Snyder, Stephen E.; Wang, Junling; Cooke, Jesse L.; Baquet, Claudia

    2004-01-01

    BACKGROUND: Cancer is the second leading cause of death in the United States and a major contributor to healthcare expenditure. There are few studies examining disparities in treatment costs. Studies that do exist are dominated by the cost of hospital care. METHODS: Utilizing Maryland Medicaid administrative claims data, a retrospective cohort, design was employed to examine disparities in ambulatory treatment costs of breast, colorectal and prostate cancer treatment by region, race and gender. We report mean and median results by each demographic category and test for the statistical significance of each. Lorenz curves are plotted and Gini coefficients calculated for each type of cancer. RESULTS: We do not find a consistent trend in ambulatory costs across the three cancers by traditional demographic variables. Lorenz curves indicate highly unequal distributions of costs. Gini coefficients are 0.687 for breast cancer, 0.757 for colorectal cancer and 0.774 for prostate cancer. CONCLUSION: Significant variation in nonhospital-based expenditures exists for breast, colorectal and prostate cancers in a population of homogeneous socioeconomic status and uniform insurance entitlement. Observed individual-level disparities are not consistent across cancers by region, race or gender, but the majority of this low-income population receives very little ambulatory care. Images Figure 2 PMID:15622686

  18. Gender Disparity in Late-life Cognitive Functioning in India: Findings From the Longitudinal Aging Study in India

    PubMed Central

    Shih, Regina; Feeney, Kevin; Langa, Kenneth M.

    2014-01-01

    Objectives. To examine gender disparities in cognitive functioning in India and the extent to which education explains this disparity in later life. Methods. 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. Results. 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. Discussion. 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. PMID:24622150

  19. 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

  20. Global health disparities: crisis in the diaspora.

    PubMed Central

    Cox, Raymond L.

    2004-01-01

    The United States spends more than the rest of the world on healthcare. In 2000, the U.S. health bill was 1.3 trillion dollars, 14.5% of its gross domestic product. Yet, according to the WHO World Health Report 2000, the United States ranked 37th of 191 member nations in overall health system performance. Racial/ethnic disparities in health outcomes are the most obvious examples of an unbalanced healthcare system. This presentation will examine health disparities in the United States and reveal how health disparities among and within countries affect the health and well-being of the African Diaspora. PMID:15101675

  1. Fast Radiometry Guided Fusion of Disparity Images

    NASA Astrophysics Data System (ADS)

    Schmid, Stephan; Fritsch, Dieter

    2016-06-01

    Previous work on disparity map fusion has mostly focused on geometric or statistical properties of disparity maps. Since failure of stereo algorithms is often consistent in many frames of a scene, it cannot be detected by such methods. Instead, we propose to use radiometric information from the original camera images together with externally supplied camera pose information to detect mismatches. As radiometric information is local information, the computations in the proposed algorithm for disparity fusion can be decoupled and parallelized to a very large degree, which allows us to easily achieve real-time performance.

  2. Conquering racial disparities in perinatal outcomes.

    PubMed

    Willis, Earnestine; McManus, Patricia; Magallanes, Norma; Johnson, Sheri; Majnik, Amber

    2014-12-01

    Infant mortality rate (IMR) is a reference indicator for societal health status. Trend analysis of IMR highlights 2 challenges to overcome in the United States: (1) US IMR is higher than most industrialized countries and (2) there are persistent racial/ethnic disparities in birth outcomes, especially for blacks. Racial/ethnic infant mortality disparities result from the complex interplay of adverse social, economic, and environmental exposures. In this article, racial/ethnic disparities are discussed, highlighting trends, the role of epigenetics in understanding mechanisms, key domains of community action planning, and programs and policies addressing the racial gaps in adverse birth outcomes. PMID:25459778

  3. Radiocarbon in dissolved organic carbon of the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Druffel, E. R. M.; Griffin, S.; Coppola, A. I.; Walker, B. D.

    2016-05-01

    Marine dissolved organic carbon (DOC) is produced in the surface ocean though its radiocarbon (14C) age in the deep ocean is thousands of years old. Here we show that ≥10% of the DOC in the deep North Atlantic is of postbomb origin and that the 14C age of the prebomb DOC is ≥4900 14C year, ~900 14C year older than previous estimates. We report 14C ages of DOC in the deep South Atlantic that are intermediate between values in the North Atlantic and the Southern Ocean. Finally, we conclude that prebomb DOC 14C ages are older and a portion of deep DOC is more dynamic than previously reported.

  4. 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. PMID:22517758

  5. 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. ?? 1984 Nature Publishing Group.

  6. 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.

  7. 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.

  8. Urban poverty and infant mortality rate disparities.

    PubMed Central

    Sims, Mario; Sims, Tammy L.; Bruce, Marino A.

    2007-01-01

    This study examined whether the relationship between high poverty and infant mortality rates (IMRs) varied across race- and ethnic-specific populations in large urban areas. Data were drawn from 1990 Census and 1992-1994 Vital Statistics for selected U.S. metropolitan areas. High-poverty areas were defined as neighborhoods in which > or = 40% of the families had incomes below the federal poverty threshold. Bivariate models showed that high poverty was a significant predictor of IMR for each group; however, multivariate analyses demonstrate that maternal health and regional factors explained most of the variance in the group-specific models of IMR. Additional analysis revealed that high poverty was significantly associated with minority-white IMR disparities, and country of origin is an important consideration for ethnic birth outcomes. Findings from this study provide a glimpse into the complexity associated with infant mortality in metropolitan areas because they suggest that the factors associated with infant mortality in urban areas vary by race and ethnicity. PMID:17444423

  9. Asymmetries and errors in perception of depth from disparity suggest a multicomponent model of disparity processing.

    PubMed

    Landers, D D; Cormack, L K

    1997-02-01

    In three experiments, asymmetries between the processing of crossed and uncrossed disparities were investigated. The target was a luminance-defined circle concentric to a fixation mark, viewed stereoscopically on a computer monitor for 105 msec. Fifteen disparities were presented according to the method of constant stimuli. Observers indicated the apparent direction of target depth relative to fixation. All experiments measured both the accuracy and latency of this response. Experiment 1 showed fewer errors and shorter reaction times for identifying crossed disparities. Experiments 2 and 3 replicated Experiment 1 and also showed that observers may often perceive a target in the direction opposite that prescribed by the disparity information. We propose that the asymmetries and reversals result from differences in computation of sign, not of magnitude. This notion is consistent with a scheme of continuous disparity tuning and accounts for such asymmetries and errors without positing disparity pooling mechanisms. PMID:9055617

  10. 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.

  11. Healthcare Quality and Disparities in Women

    MedlinePlus

    ... Report (NHDR) focuses on “prevailing disparities in health care delivery as it relates to racial factors and socioeconomic factors in priority populations.” Priority populations include racial ...

  12. Teen Birth Rates Drop, But Disparities Persist

    MedlinePlus

    ... Features Teen Birth Rates Drop, But Disparities Persist Language: English Español (Spanish) Recommend on Facebook Tweet Share Compartir The feature you selected is no longer available. In 10 seconds you will be automatically redirected to the CDC. ...

  13. Cancer Health Disparities | Did You Know?

    Cancer.gov

    How does cancer affect people from different populations and groups? Cancer health disparities happen when there are higher rates of new diagnoses and cancer death rates among certain races, ethnicities, or other population groups.

  14. EGRP-Supported Health Disparities Research

    Cancer.gov

    The National Cancer Institute has targeted the reduction of cancer-related health disparities, differences in the incidence, prevalence, mortality, and burden of cancer and related adverse health conditions, as an important challenge.

  15. 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. PMID:26252648

  16. Socioeconomic Dynamics of Gender Disparity in Childhood Immunization in India, 1992–2006

    PubMed Central

    Prusty, Ranjan Kumar; Kumar, Abhishek

    2014-01-01

    Background Recent evidence indicated that gender disparity in child health is minimal and narrowed over time in India. However, considering the geographical and socio-cultural diversity in India, the gender gap may persist across disaggregated socioeconomic context which may be masked by average level. This study examines the dynamics of gender disparity in childhood immunization across regions, residence, wealth, caste and religion in India during 1992–2006. Method We used multi-waves of the cross-sectional data of National Family Health Survey conducted in India between 1992–93 and 2005–06. Gender disparity ratio was used to measure the gender gap in childhood immunization across the selected socioeconomic characteristics. Multinomial regression analysis was used to examine the gender gap after accounting for other covariates. Result Results indicate that, at aggregate level, gender disparity in full immunization is minimal and has stagnated during the study period. However, gender disparity – disfavouring female children – becomes apparent across the regions, poor households, and religion - particularly among Muslims. Adjusted gender disparity ratio indicates that, full immunization is lower among female than male children of the western region, poor household and among Muslims. Between 1992–93 and 2005–06, the disparity in full immunization had narrowed in the northern region whereas it had, astonishingly, increased in some of the western and southern states of the country. Conclusion Our findings emphasize the need to integrate gender issues in the ongoing immunization programme in India, with particular attention to urban areas, developed states, and to the Muslim community. PMID:25127396

  17. Residential Segregation and Disparities in Healthcare Services Utilization

    PubMed Central

    Dinwiddie, Gniesha Y.; Chan, Kitty S.; McCleary, Rachael

    2012-01-01

    Using data from the 2006 Medical Expenditure Panel Survey and the 2000 Census, we explored whether race/ethnic disparities in healthcare use were associated with residential segregation. We used five measures of healthcare use: office based physician visits, outpatient department physician visits, visits to nurses and physician’s assistants, visits to other health professionals, and having a usual source of care (USC). For each individual, we controlled for age, gender, marital status, insurance status, income, educational attainment, employment status, region, and health status. We used the racial-ethnic composition of the zip code to control for residential segregation. Our findings suggest that disparities in healthcare utilization are related to both individuals’ racial and ethnic identity and the racial and ethnic composition of their communities. Therefore, efforts to improve access to health care services and to eliminate healthcare disparities for African Americans and Hispanics should not only focus on individual-level factors but also include community-level factors. PMID:21976416

  18. 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., Jr.; 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

  19. Infants' sensitivity to vertical disparity for depth perception

    NASA Astrophysics Data System (ADS)

    Tsuruhara, Aki; Kaneko, Hirohiko; Kanazawa, So; Otsuka, Yumiko; Shirai, Nobu; Yamaguchi, Masami K.

    2013-05-01

    Both horizontal and vertical binocular disparities produce depth perception in adults. In developmental studies, infants aged around 4 to 6 months were shown to perceive depth from horizontal disparity. However, infants' sensitivity to vertical disparity has not been shown clearly. To examine the sensitivity in infants, this study measured preferential looking behavior of infants aged 20 to 27 weeks. Results showed a significant preference for the stimulus with vertical disparity, providing the first evidence of infants' sensitivity to vertical disparity. The infants in the same age group did not show preference for stimulus with horizontal disparity when the stimulus were comparable to the stimulus with vertical disparity, while their sensitivity to horizontal disparity was confirmed with the stimuli used in a previous study. Our results would suggest that properties in processing horizontal and vertical disparities are different in infancy, and that the sensitivity to horizontal disparity are still premature in 27 weeks after birth.

  20. Allele-specific disparity in breast cancer

    PubMed Central

    2011-01-01

    Background In a cancer cell the number of copies of a locus may vary due to amplification and deletion and these variations are denoted as copy number alterations (CNAs). We focus on the disparity of CNAs in tumour samples, which were compared to those in blood in order to identify the directional loss of heterozygosity. Methods We propose a numerical algorithm and apply it to data from the Illumina 109K-SNP array on 112 samples from breast cancer patients. B-allele frequency (BAF) and log R ratio (LRR) of Illumina were used to estimate Euclidian distances. For each locus, we compared genotypes in blood and tumour for subset of samples being heterozygous in blood. We identified loci showing preferential disparity from heterozygous toward either the A/B-allele homozygous (allelic disparity). The chi-squared and Cochran-Armitage trend tests were used to examine whether there is an association between high levels of disparity in single nucleotide polymorphisms (SNPs) and molecular, clinical and tumour-related parameters. To identify pathways and network functions over-represented within the resulting gene sets, we used Ingenuity Pathway Analysis (IPA). Results To identify loci with a high level of disparity, we selected SNPs 1) with a substantial degree of disparity and 2) with substantial frequency (at least 50% of the samples heterozygous for the respective locus). We report the overall difference in disparity in high-grade tumours compared to low-grade tumours (p-value < 0.001) and significant associations between disparity in multiple single loci and clinical parameters. The most significantly associated network functions within the genes represented in the loci of disparity were identified, including lipid metabolism, small-molecule biochemistry, and nervous system development and function. No evidence for over-representation of directional disparity in a list of stem cell genes was obtained, however genes appeared to be more often altered by deletion than by

  1. Modeled natural and excess radiocarbon: Sensitivities to the gas exchange formulation and ocean transport strength

    NASA Astrophysics Data System (ADS)

    Müller, S. A.; Joos, F.; Plattner, G.-K.; Edwards, N. R.; Stocker, T. F.

    2008-09-01

    Observation-based surface ocean Δ14C distributions and regional inventories for excess, bomb-produced radiocarbon are compared with results of two ocean models of intermediate complexity. By applying current descriptions of the air-sea gas exchange the models produce similar column inventories for excess 14C among all basins. This result is robust across a wide range of transport parameter settings, but inconsistent with data-based inventories. In the absence of evidence of fundamentally different gas exchange mechanisms in the North Atlantic than in the other basins, we infer regional North Atlantic 14C inventories which are considerably smaller than previous estimates. The results further suggest that the gas exchange velocity field should be reduced by (19 ± 16)%, which corresponds to a global mean air-sea gas transfer rate for CO2 in seawater of 17.1 ± 3.3 cm h-1, to find good agreement of simulated quantities with a range of data-based metrics.

  2. Riverine Export of Terrestrial Organic Carbon Investigated by Radiocarbon Dating of Lignin Phenols in River-influenced Marine Core-top Sediments

    NASA Astrophysics Data System (ADS)

    Mollenhauer, G.; Huang, Y.; Kreutz, R.; Kusch, S.; Rethemeyer, J.; Schefuss, E.

    2009-12-01

    Rivers are the principal pathways for the export of terrestrial organic carbon (OC) from the continent to the ocean in the form of particulate and dissolved OC, thereby directly linking the terrestrial and marine carbon cycles. Several recent studies using radiocarbon dates of terrigenous biomarkers in core-top marine sediments to investigate residence time of terrestrial plant biomass in terrestrial reservoirs have reported long-chain aliphatic compounds, i.e., n-alkanes and n-fatty acids as biomarkers for leaf waxes of higher plants, to be significantly pre-aged upon deposition in marine sediments. This could either be interpreted as resulting from admixture of fossil material (e.g., from fossil fuels) to compounds recently produced and rapidly transferred to the marine realm, or to reflect substantial residence time of terrigenous compounds in intermediate reservoirs like soils and fluvial sediments. However, plant leaf waxes are minor components of the terrestrial organic matter and quantitatively unimportant for understanding export rate of terrestrial organic carbon to the ocean. Moreover, long-chain aliphatic lipids are not exclusively derived from higher plants. In contrast, lignin comprises a quarter of the biomass of and is exclusively produced by terrestrial higher plants. Lignin is also considered to be resistant to microbial and enzymatic breakdown and has been used as tracer for terrestrial OC supply to marine sediments. Recently developed HPLC/MS methodology now allows isolation of lignin phenols from natural samples for radiocarbon dating. Here we present radiocarbon ages of lignin phenols isolated from core-top sediments recovered from three different river mouths: the Weser River draining NW and central Germany, the Danube originating in the Alps region and flowing through Southeastern Europe to the Black Sea, and the Congo River representing one of the major tropical river systems. These data are compared with radiocarbon ages of co

  3. Morphological and biomechanical disparity of crocodile-line archosaurs following the end-Triassic extinction

    PubMed Central

    Stubbs, Thomas L.; Pierce, Stephanie E.; Rayfield, Emily J.; Anderson, Philip S. L.

    2013-01-01

    Mesozoic crurotarsans exhibited diverse morphologies and feeding modes, representing considerable ecological diversity, yet macroevolutionary patterns remain unexplored. Here, we use a unique combination of morphological and biomechanical disparity metrics to quantify the ecological diversity and trophic radiations of Mesozoic crurotarsans, using the mandible as a morpho-functional proxy. We recover three major trends. First, the diverse assemblage of Late Triassic crurotarsans was morphologically and biomechanically disparate, implying high levels of ecological variation; but, following the end-Triassic extinction, disparity declined. Second, the Jurassic radiation of marine thalattosuchians resulted in very low morphological disparity but moderate variation in jaw biomechanics, highlighting a hydrodynamic constraint on mandibular form. Third, during the Cretaceous terrestrial radiations of neosuchians and notosuchians, mandibular morphological variation increased considerably. By the Late Cretaceous, crocodylomorphs evolved a range of morphologies equalling Late Triassic crurotarsans. By contrast, biomechanical disparity in the Cretaceous did not increase, essentially decoupling from morphology. This enigmatic result could be attributed to biomechanical evolution in other anatomical regions (e.g. cranium, dentition or postcranium), possibly releasing the mandible from selective pressures. Overall, our analyses reveal a complex relationship between morphological and biomechanical disparity in Mesozoic crurotarsans that culminated in specialized feeding ecologies and associated lifestyles. PMID:24026826

  4. Morphological and biomechanical disparity of crocodile-line archosaurs following the end-Triassic extinction.

    PubMed

    Stubbs, Thomas L; Pierce, Stephanie E; Rayfield, Emily J; Anderson, Philip S L

    2013-11-01

    Mesozoic crurotarsans exhibited diverse morphologies and feeding modes, representing considerable ecological diversity, yet macroevolutionary patterns remain unexplored. Here, we use a unique combination of morphological and biomechanical disparity metrics to quantify the ecological diversity and trophic radiations of Mesozoic crurotarsans, using the mandible as a morpho-functional proxy. We recover three major trends. First, the diverse assemblage of Late Triassic crurotarsans was morphologically and biomechanically disparate, implying high levels of ecological variation; but, following the end-Triassic extinction, disparity declined. Second, the Jurassic radiation of marine thalattosuchians resulted in very low morphological disparity but moderate variation in jaw biomechanics, highlighting a hydrodynamic constraint on mandibular form. Third, during the Cretaceous terrestrial radiations of neosuchians and notosuchians, mandibular morphological variation increased considerably. By the Late Cretaceous, crocodylomorphs evolved a range of morphologies equalling Late Triassic crurotarsans. By contrast, biomechanical disparity in the Cretaceous did not increase, essentially decoupling from morphology. This enigmatic result could be attributed to biomechanical evolution in other anatomical regions (e.g. cranium, dentition or postcranium), possibly releasing the mandible from selective pressures. Overall, our analyses reveal a complex relationship between morphological and biomechanical disparity in Mesozoic crurotarsans that culminated in specialized feeding ecologies and associated lifestyles. PMID:24026826

  5. 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 ...

  6. Morphotype disparity in the Precambrian

    NASA Astrophysics Data System (ADS)

    Moore, Rachael; Reitner, Joachim; Braiser, Martin; Donoghue, Phil; Schirrmeister, Bettina

    2015-04-01

    Prokaryotes have dominated life on Earth for over 2 billion years. Throughout the Precambrian, prokaryotes acted as the major biological impetus for both large and small scale environmental changes. Yet, very little is known about the composition, diversity and evolution of ancient microbial communities due to poor preservation during the Precambrian period. Previous studies of fossils that date to this period relied mainly on light microscopy to identify microfossil morphology and abundance, with limited success. Here we present novel analyses of the microbial remains found in Precambrian stromatolites using Synchrotron Radiation x-Ray Tomographic Microscopy (SRXTM). Microfossils found in samples of three Precambrian deposits, 3.45 Ga Strelley Pool, Australia, 2.1 Ga Gunflint Chert, Canada, and 650 Ma Rasthof Cap Carbonate, Namibia, have been reconstructed in 3D. Based on four scans from each sample, we estimated size and abundance of spheroidal microfossils within those deposits. Our findings show that while cell abundance decreased towards the end of the Precambrian, the biovolume of microfossils within the host rock remained relatively constant. Additionally, both size and disparity increase through time. Constant biovolumes and yet different sizes for these three deposits, point towards a negative correlation of large cell size and cell abundance. This negative correlation indicates that the systems in which these prokaryotes lived may have been biolimited. Both, gas exchange and nutrient uptake in prokaryotes function via diffusion. Therefore, one would expect bacteria to evolve towards an increasing surface to volume ratio. Increased cell sizes, and hence decreased overall surface to volume ratio observed in our data, suggest the influence of other selective factors. Decreased abundance and increased cell size could potentially be associated to changes in nutrient availability and the occurrence of predation. As cells increased in size, more nutrients would

  7. New radiocarbon measurement methods in the Hertelendi Laboratory, Hungary

    NASA Astrophysics Data System (ADS)

    Janovics, Róbert; Major, István; Rinyu, László; Veres, Mihály; Molnár, Mihály

    2013-04-01

    In this paper we present two very different and novel methods for C-14 measurement from dissolved inorganic carbonate (DIC) of water samples. A new LSC sample preparation method for liquid scintillation C-14 measurements was implemented in the ATOMKI. The first method uses direct absorption into a special absorbent (Carbosorb E®) and a following liquid scintillation measurement. Typical sample size is 20-40 litre of water. The developed CO2 absorption method is fast, and simple. The C-14 activities is measured by an ultra low background LSC (TRI-CARB 3170 TR/SL, Perkin Elmer) including quenching parameter (tSIE).The corresponding limit of C-14 dating is 31200 year. Several tests were executed with old borehole CO2 gas without significant content of C-14 and also performed on samples of known C-14 activities between 29 and 7000 pMC, previously measured by GPC. The combined uncertainty of the described determination is about 2 % in the case of recent carbon. It is a very cost-effective and easy to use method based on a novel and simple static absorption process for the CO2 extracted from groundwater. The other very sensitive method is based on accelerator mass spectrometry (AMS) using gas ion source. This method does not require graphite generation and a small volume of water sample (1-20mL) is enough for the radiocarbon measurement. The procedure is very similar to pre-treatment of carbonate contained sample preparation for stable isotope measurement with gasbench technique. We applied a MICADAS type accelerator mass spectrometry (AMS) with gas ion source for C-14 analysis. The radiocarbon content of water was sat free with phosphoric acid and then the headspace gas was rinsed vials. The whole measurement needs only 20 min of each sample. The precision of measurement is better than 1% for modern samples. The preparation is vastly reduced compared to the other AMS methods and principally allows fully automated measurements of groundwater samples with an auto

  8. 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

  9. 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.

  10. Intermediate water radiocarbon off west Sumatra during the last 45,000 years

    NASA Astrophysics Data System (ADS)

    De Pol-Holz, R.; Mohtadi, M.; Southon, J.

    2012-04-01

    Radiocarbon content of intermediate waters originating from the Southern Ocean is held as the likely smoking gun of the events that triggered the atmospheric CO2 rise and its radiocarbon content decline during the last glacial-interglacial transition. Extremely depleted radiocarbon has been found off the coast of Baja California, the Galapagos and the Arabian Sea, but not unequivocally elsewhere. Knowing the route of the old water is therefore central for the mechanistic linkage of Southern Ocean processes and the atmospheric response. Here, we present high-resolution radiocarbon content of intermediate depth waters off west Sumatra in the attempt to trace the hypothetical route of old water emanating near Antarctica. Sediment core SO189-39KL (0°47'S, 99°55'E, 517 m) resulted in a 1350 cm hemipelagic sedimentary sequence that spans the last 45,000 years and it was sampled for planktonic and benthic foraminifera radiocarbon determinations at a centennial time resolution. Besides the planktonic radiocarbon age control points, we attempted an independent stratigraphy based on the Mg/Ca sea surface temperature evolution and its apparent similarity with Antarctic Ice core records. This allowed us to infer surface reservoir ages as well as the D14C of the intermediate waters. Our results show that throughout the LGM and the entire deglaciation, radiocarbon content at 500 m depth off west Sumatra remained in equilibrium with the contemporaneous atmosphere, discarding this area as a probable route for the spreading of the old water along its way to northern latitudes. These results add up to increasing evidence that the radiocarbon content of intermediate waters originating from the Southern Ocean was not influenced by the upwelling of a large abyssal old water reservoir, as it has been hypothesized in order to explain the atmospheric deglacial records.

  11. 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.

  12. 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.

  13. Racial Healthcare Disparities: A Social Psychological Analysis.

    PubMed

    Penner, Louis A; Hagiwara, Nao; Eggly, Susan; Gaertner, Samuel L; Albrecht, Terrance L; Dovidio, John F

    2013-01-01

    Around the world, members of racial/ethnic minority groups typically experience poorer health than members of racial/ethnic majority groups. The core premise of this article is that thoughts, feelings, and behaviors related to race and ethnicity play a critical role in healthcare disparities. Social psychological theories of the origins and consequences of these thoughts, feelings, and behaviors offer critical insights into the processes responsible for these disparities and suggest interventions to address them. We present a multilevel model that explains how societal, intrapersonal, and interpersonal factors can influence ethnic/racial health disparities. We focus our literature review, including our own research, and conceptual analysis at the intrapersonal (the race-related thoughts and feelings of minority patients and non-minority physicians) and interpersonal levels (intergroup processes that affect medical interactions between minority patients and non-minority physicians). At both levels of analysis, we use theories of social categorization, social identity, contemporary forms of racial bias, stereotype activation, stigma, and other social psychological processes to identify and understand potential causes and processes of health and healthcare disparities. In the final section, we identify theory-based interventions that might reduce ethnic/racial disparities in health and healthcare. PMID:25197206

  14. Health policy, disparities, and the kidney.

    PubMed

    Williams, Amy W

    2015-01-01

    Kidney care and public policy have been linked for 40 years, with various consequences to outcomes. The 1972 Social Security Amendment, Section 2991, expanded Medicare coverage for all modalities of dialysis and transplant services and non-kidney-related care to those with end-stage renal disease (ESRD) regardless of age. This first and only disease-specific entitlement program was a step toward decreasing disparities in access to care. Despite this, disparities in kidney disease outcomes continue as they are based on many factors. Over the last 4 decades, policies have been enacted to understand and improve the delivery of ESRD care. More recent policies include novel shared-risk payment models to ensure quality and decrease costs. This article discusses the impact or potential impact of selected policies on health disparities in advanced chronic kidney disease and ESRD. Although it is too early to know the consequences of newer policies (Affordable Care Act, ESRD Prospective Payment System, Quality Incentive Program, Accountable Care Organizations), their goal of improving access to timely patient-centered appropriate affordable and quality care should lessen the disparity gap. The Nephrology community must leverage this dynamic state of care-delivery model redesign to decrease kidney-related health disparities. PMID:25573513

  15. Racial Healthcare Disparities: A Social Psychological Analysis

    PubMed Central

    Penner, Louis A.; Hagiwara, Nao; Eggly, Susan; Gaertner, Samuel L.; Albrecht, Terrance L.; Dovidio, John F.

    2014-01-01

    Around the world, members of racial/ethnic minority groups typically experience poorer health than members of racial/ethnic majority groups. The core premise of this article is that thoughts, feelings, and behaviors related to race and ethnicity play a critical role in healthcare disparities. Social psychological theories of the origins and consequences of these thoughts, feelings, and behaviors offer critical insights into the processes responsible for these disparities and suggest interventions to address them. We present a multilevel model that explains how societal, intrapersonal, and interpersonal factors can influence ethnic/racial health disparities. We focus our literature review, including our own research, and conceptual analysis at the intrapersonal (the race-related thoughts and feelings of minority patients and non-minority physicians) and interpersonal levels (intergroup processes that affect medical interactions between minority patients and non-minority physicians). At both levels of analysis, we use theories of social categorization, social identity, contemporary forms of racial bias, stereotype activation, stigma, and other social psychological processes to identify and understand potential causes and processes of health and healthcare disparities. In the final section, we identify theory-based interventions that might reduce ethnic/racial disparities in health and healthcare. PMID:25197206

  16. 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.

  17. Biological Removal of Radiocarbon-14 from Irradiated Graphite

    SciTech Connect

    Molokwane, P.E.; Chirwa, E.M.N.

    2008-07-01

    This paper reports on the preliminary study on the bioseparation of radiocarbon-14 (C-14) using a mixed-culture of microorganisms. The bioseparation principle is critically analyzed and is benchmarked against existing C-14 separation methods using physical chemical processes. The preliminary study indicated probable bio-separate of C-14 from solution prepared from a nuclear graphite mixture, even though the findings need to be verified. The current experiment consisted of a growth vessel and a bio-filter operated in a closed loop. The bio-filter was not installed for the purpose of treatment but rather as a method of isolation of microorganisms for further processing. Significant amounts of C-14 were detected in the trapped cells in the bio-filter, significantly higher than in controls taken before adding carbon sources containing C-14. The microorganisms were grown under micro-aerobic conditions with graphite carbon and commercially purchased powdered carbon as the predominant supplied carbon sources. Small amounts of sucrose (500 mg/L) were added at 48 hour intervals to maintain culture balance. A proof of concept study is underway to determine the C-14 mass balance, characterize the microorganisms in the reactor, and establish the presence or absence of processes that might have affected the preliminary observations. This research represents an exploration into a new field using a new philosophy for treatment of C-14 in low-level waste. (authors)

  18. 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

  19. 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. PMID:21338118

  20. 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.

  1. 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

  2. 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.

  3. Construction of reliable radiocarbon-based chronologies for speleothems

    NASA Astrophysics Data System (ADS)

    Lechleitner, Franziska; Fohlmeister, Jens; McIntyre, Cameron; Baldini, Lisa M.; Jamieson, Robert A.; Hercman, Helena; Gasiorowski, Michal; Pawlak, Jacek; Stefaniak, Krzysztof; Socha, Pawel; Eglinton, Timothy I.; Baldini, James U. L.

    2016-04-01

    Speleothems have become one of the most widely applied archives for paleoclimate research. One of their key advantages is their amenability for U-series dating, often producing excellent high precision chronologies. However, stalagmites with high detrital Th or very low U concentrations are problematic to date using U-series, and sometimes need to be discarded from further paleoclimate analysis. Radiocarbon chronologies could present an alternative for stalagmites that cannot be dated using U-series, if offsets from the "dead carbon fraction" (DCF) can be resolved. The DCF is a variable reservoir effect introduced by the addition of 14C-dead carbon from host rock dissolution and soil organic matter. We present a novel age modeling technique that provides accurate 14C-based chronologies for stalagmites. As this technique focuses on the long-term decay pattern of 14C, it is only applicable on stalagmites that show no secular variability in their 14C-depth profiles, but is independent of short-term DCF variations. In order to determine whether a stalagmite is suitable for this method without direct knowledge of long-term trends in the DCF, we highlight how other geochemical proxies (δ13C, Mg/Ca) can provide additional information on changes in karst hydrology, soil conditions, and climate that would affect DCF. We apply our model on a previously published U-Th dated stalagmite 14C dataset from Heshang Cave, China with excellent results, followed by a previously 'undateable' stalagmite from southern Poland.

  4. 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

  5. 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

  6. Distributions of dissolved organic and inorganic carbon and radiocarbon in the eastern North Pacific continental margin

    NASA Astrophysics Data System (ADS)

    Bauer, James E.; Druffel, Ellen R. M.; Wolgast, David M.; Griffin, Sheila; Masiello, Caroline A.

    Temporal variations in the natural radiocarbon ( 14C) signatures of dissolved organic and inorganic carbon (DOC and DIC, respectively) in seawater have been studied previously (Druffel, E.R.M., Bauer, J.E., Williams, P.M., Griffin, S., Wolgast, D.M., 1996. Seasonal variability of radiocarbon in particulate organic carbon in the northeast Pacific. J. Geophys. Res. 101, 20 543-20 552; Bauer, J.E., Druffel, E.R.M., Williams, P.M., Wolgast, D.M., Griffin, S., 1998. Temporal variability in dissolved organic carbon and radiocarbon in the eastern North Pacific Ocean. J. Geophys. Res. 103, 2867-2882) at a long-term time-series station (Sta. M: 32°N, 123W) in the eastern North Pacific located at the eastern edge of the North Pacific abyssal plain. In June 1995 a transect was made from Sta. M inshore to approximately 500 m depth in order to evaluate the distributions of 14C in DOC and DIC from the abyssal plain to the upper continental slope. Concentrations and Δ 14C values of DOC in mixed layer waters (25 and 85 m) decreased toward the upper slope. In deeper waters, concentrations and Δ 14C values were in general similar at all three sites. Differences in DOC concentrations and Δ 14C-DOC between Sta. M and the rise and upper slope sites were explained in part by the mixing of DOC and Δ 14C along constant density ( σt) surfaces. However, specific deviations from conservative behavior due to mixing were observed for Δ 14C-DOC at mesopelagic (˜700 m) and near-bottom (˜3600- 3900 m) depths of the continental rise. Comparable findings are reported for DIC, where σt-normalized concentrations and Δ 14C values in Sta. M, rise and upper slope waters were similar, with the exception of slight increases in concentrations and Δ 14C values in near-bottom waters of the rise. These observations indicate that both DOC and DIC in continental rise and slope surface waters of the eastern North Pacific Ocean margin are comprised of a component of actively upwelled material derived

  7. Trends in Longevity in the Americas: Disparities in Life Expectancy in Women and Men, 1965-2010

    PubMed Central

    Hambleton, Ian R.; Howitt, Christina; Jeyaseelan, Selvi; Murphy, Madhuvanti M.; Hennis, Anselm J; Wilks, Rainford; Harris, E. Nigel; MacLeish, Marlene; Sullivan, Louis

    2015-01-01

    Objective We describe trends in life expectancy at birth (LE) and between-country LE disparities since 1965, in Latin America and the Caribbean. Methods & Findings LE trends since 1965 are described for three geographical sub-regions: the Caribbean, Central America, and South America. LE disparities are explored using a suite of absolute and relative disparity metrics, with measurement consensus providing confidence to observed differences. LE has increased throughout Latin America and the Caribbean. Compared to the Caribbean, LE has increased by an additional 6.6 years in Central America and 4.1 years in South America. Since 1965, average reductions in between-country LE disparities were 14% (absolute disparity) and 23% (relative disparity) in the Caribbean, 55% and 51% in Central America, 55% and 52% in South America. Conclusions LE in Latin America and the Caribbean is exceeding ‘minimum standard’ international targets, and is improving relative to the world region with the highest human longevity. The Caribbean, which had the highest LE and the lowest between-country LE disparities in Latin America and the Caribbean in 1965-70, had the lowest LE and the highest LE disparities by 2005-10. Caribbean Governments have championed a collaborative solution to the growing burden of non-communicable disease, with 15 territories signing on to the Declaration of Port of Spain, signalling regional commitment to a coordinated public-health response. The persistent LE inequity between Caribbean countries suggests that public health interventions should be tailored to individual countries to be most effective. Between- and within-country disparity monitoring for a range of health metrics should be a priority, first to guide country-level policy initiatives, then to contribute to the assessment of policy success. PMID:26091090

  8. Social Determinants of Racial Disparities in CKD.

    PubMed

    Norton, Jenna M; Moxey-Mims, Marva M; Eggers, Paul W; Narva, Andrew S; Star, Robert A; Kimmel, Paul L; Rodgers, Griffin P

    2016-09-01

    Significant disparities in CKD rates and outcomes exist between black and white Americans. Health disparities are defined as health differences that adversely affect disadvantaged populations, on the basis of one or more health outcomes. CKD is the complex result of genetic and environmental factors, reflecting the balance of nature and nurture. Social determinants of health have an important role as environmental components, especially for black populations, who are disproportionately disadvantaged. Understanding the social determinants of health and appreciating the underlying differences associated with meaningful clinical outcomes may help nephrologists treat all their patients with CKD in an optimal manner. Altering the social determinants of health, although difficult, may embody important policy and research efforts, with the ultimate goal of improving outcomes for patients with kidney diseases, and minimizing the disparities between groups. PMID:27178804

  9. Disparities in Primary Care EHR Adoption Rates

    PubMed Central

    Mack, Dominic; Zhang, Shun; Douglas, Megan; Sow, Charles; Strothers, Harry; Rust, George

    2016-01-01

    This study evaluates electronic health record (EHR) adoption by primary care providers in Georgia to assess adoption disparities according to practice size and type, payer mix, and community characteristics. Frequency variances of EHR “Go Live” status were estimated. Odds ratios were calculated by univariate and multivariate logistic regression models. Large practices and community health centers (CHCs) were more likely to Go Live (>80% EHR adoption) than rural health clinics and other underserved settings (53%). A significantly lower proportion (68.9%) of Medicaid predominant providers had achieved Go Live status and had a 47% higher risk of not achieving Go Live status than private insurance predominant practices. Disparities in EHR adoption rates may exacerbate existing disparities in health outcomes of patients served by these practices. Targeted support such as that provided to CHCs would level the playing field for practices now at a disadvantage. PMID:27587942

  10. Persistent Disparities in Adult Hematopoietic Cell Transplantation.

    PubMed

    Crockett, David G; Loberiza, Fausto R

    2015-09-01

    The use of large databases has provided advancements in the understanding of racial, ethnic, and socioeconomic disparities in the field of adult hematopoietic cell transplants (HCT). Disparities exist on individual, institutional, and systemic levels for both allogeneic and autologous HCT. We reviewed the most recent publications that utilized large databases to elucidate disparities in HCT and placed them into historical context of the other major studies in the field. Two emerging themes were identified. These themes are persistent inequalities in both allogeneic HCT and autologous HCT for myeloma and the importance of improving homogeneity of care in HCT. Minimization of inequalities can be achieved only with an understanding of the persistent barriers that exist in the field. PMID:26104908

  11. Spaceborne multiview image compression based on adaptive disparity compensation with rate-distortion optimization

    NASA Astrophysics Data System (ADS)

    Li, Shigao; Su, Kehua; Jia, Liming

    2016-01-01

    Disparity compensation (DC) and transform coding are incorporated into a hybrid coding to reduce the code-rate of multiview images. However, occlusion and inaccurate disparity estimations (DE) impair the performance of DC, especially in spaceborne images. This paper proposes an adaptive disparity-compensation scheme for the compression of spaceborne multiview images, including stereo image pairs and three-line-scanner images. DC with adaptive loop filter is used to remove redundancy between reference images and target images and a wavelet-based coding method is used to encode reference images and residue images. In occlusion regions, the DC efficiency may be poor because no interview correlation exists. A rate-distortion optimization method is thus designed to select the best prediction mode for local regions. Experimental results show that the proposed scheme can provide significant coding gain compared with some other similar coding schemes, and the time complexity is also competitive.

  12. Race and healthcare disparities: overcoming vulnerablity.

    PubMed

    Stone, John

    2002-01-01

    The paper summarizes recently published data and recommendations about healthcare disparities experienced by African Americans who have Medicare or other healthcare coverage. Against this background the paper addresses the ethics of such disparities and how disadvantages of vulnerable populations like African Americans are typically maintained in decision making about how to respond to such disparities. Considering how to respond to disparities reveals much that vulnerable populations would bring to the policy-making table, if they can also be heard when they get there. The paper argues that vulnerable populations like African Americans need fair representation in bodies deciding what to do about such disparities and that fairness requires proportional representation at all levels of decisions that affect healthcare--a radical change. In this decision setting, how to provide adequate protection of minorities needs much further attention. The most attractive decision-making model is deliberative democracy. The paper shows that in deliberation, fair representation requires not only having a voice in decisions, but a fair hearing of those voices. Achieving a fair hearing requires changes in norms of communication and training of all to give importance to greetings and other measures of civility and trust building, and to be open to diverse forms of expression. Decisions about how to respond to healthcare disparities would include what programs to initiate for whom, how to evaluate the programs, and what to do in response to such evaluations. Conclusions are that achieving such goals will take a sea change in how healthcare institutions and providers do their business, and that social activism at every level will be needed to effect these changes. The discussion highlights many ethical issues that need much greater attention. PMID:12546167

  13. 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

  14. Gender Disparities in Ocular Inflammatory Disorders*

    PubMed Central

    Sen, Hatice Nida; Davis, Janet; Ucar, Didar; Fox, Austin; Chan, Chi Chao; Goldstein, Debra A.

    2014-01-01

    Ocular inflammatory disorders disproportionately affect women, and the majority of affected women are of childbearing age. The role of sex or reproductive hormones has been proposed in many other inflammatory or autoimmune disorders, and findings from non-ocular autoimmune diseases suggest a complex interaction between sex hormones, genetic factors and the immune system. However, despite the age and sex bias, factors that influence this disparity are complicated and unclear. This review aims to evaluate the gender disparities in prevalence, incidence and severity of the most common infectious and non-infectious ocular inflammatory disorders. PMID:24987987

  15. Widening Geographical Disparities in Cardiovascular Disease Mortality in the United States, 1969-2011

    PubMed Central

    Singh, Gopal K.; Azuine, Romuladus E.; Siahpush, Mohammad; Williams, Shanita D.

    2015-01-01

    Objectives: This study examined trends in geographical disparities in cardiovascular-disease (CVD) mortality in the United States between 1969 and 2011. Methods: National vital statistics data and the National Longitudinal Mortality Study were used to estimate regional, state, and county-level disparities in CVD mortality over time. Log-linear, weighted least squares, and Cox regression were used to analyze mortality trends and differentials. Results: During 1969-2011, CVD mortality rates declined fastest in New England and Mid-Atlantic regions and slowest in the Southeast and Southwestern regions. In 1969, the mortality rate was 9% higher in the Southeast than in New England, but the differential increased to 48% in 2011. In 2011, Southeastern states, Mississippi and Alabama, had the highest CVD mortality rates, nearly twice the rates for Minnesota and Hawaii. Controlling for individual-level covariates reduced state differentials. State- and county-level differentials in CVD mortality rates widened over time as geographical disparity in CVD mortality increased by 50% between 1969 and 2011. Area deprivation, smoking, obesity, physical inactivity, diabetes prevalence, urbanization, lack of health insurance, and lower access to primary medical care were all significant predictors of county-level CVD mortality rates and accounted for 52.7% of the county variance. Conclusions and Global Health Implications: Although CVD mortality has declined for all geographical areas in the United States, geographical disparity has widened over time as certain regions and states, particularly those in the South, have lagged behind in mortality reduction. Geographical disparities in CVD mortality reflect inequalities in socioeconomic conditions and behavioral risk factors. With the global CVD burden on the rise, monitoring geographical disparities, particularly in low- and middle-income countries, could indicate the extent to which reductions in CVD mortality are achievable and may

  16. 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

  17. 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.

  18. 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

  19. Radiocarbon measurements at LAC-UFF: Recent performance

    NASA Astrophysics Data System (ADS)

    Linares, Roberto; Macario, Kita D.; Santos, Guaciara M.; Carvalho, Carla; dos Santos, Hellen C.; Gomes, Paulo R. S.; Castro, Maikel D.; Oliveira, Fabiana M.; Alves, Eduardo Q.

    2015-10-01

    In 2012 a single stage accelerator mass spectrometer from NEC was installed at the Radiocarbon Laboratory of Universidade Federal Fluminense (LAC-UFF), Niterói, Brazil. Here, we present a status report of our facility. We discuss some modifications applied to our combustion protocol in an attempt to reduce our procedural blank, mostly to processed organic samples. Measurements of reference materials indicate low precision and accuracy that are partially related to beam optics through the acceleration tube. We observed that once the beam current intensity increases the measured 13C+/12C+ becomes erratic. Therefore, in order to maintain the AMS-δ13C values within reasonable values, so that fractionation corrections using the spectrometer 13C+/12C+ values does not affect the final 14C results, we are forced to limit the 12C- beam intensity to ⩽30 μA. This requirement was confirmed during our accuracy tests, when measuring selected annual tree-rings wood samples from a Parana pine (Araucaria angustifolia) between 1927 and 1997 previously measured at the Keck Carbon Cycle AMS Facility (KCCAMS), at the University of California, Irvine (UCI). At the LAC-UFF tree-ring wood samples were processed and measured in 4 different batches during a period of about 5 months. The 14C results were later compared to the high-precision data obtained at KCCAMS/UCI and reached a good agreement. Recently a problem associated with graphitization yield were finally identified and new measurements with secondary standards are promising.

  20. 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.

  1. Effects of Seafloor Diagenesis on Planktic Foraminiferal Radiocarbon Ages

    NASA Astrophysics Data System (ADS)

    Wycech, J.; Kelly, D. C.

    2014-12-01

    Radiocarbon (14C) analysis of planktic foraminiferal calcite is widely used to study ocean-climate change over the past ~40 ka of Earth history. However, it is well known that planktic shell calcite typically yields 14C ages ~400 years older than those of bulk carbonate from the same sample. Such age discrepancies are problematic, and have been attributed to size-selective sediment mixing and/or differential dissolution of planktic shells within the sedimentary bioturbated zone. Another likely cause of such temporal offsets is the addition of secondary calcite to planktic shells via post-depositional diagenesis, but quantifying the deleterious effects of diagenesis on foraminiferal 14C ages has proven difficult owing to a paucity of suitable study materials. We address this problem by comparing 14C ages and δ13C values of planktic shells exhibiting a state of preservation (frosty) traditionally deemed acceptable for paleoceanographic studies to those of extremely well preserved (glassy) shells. Aliquots of frosty and glassy shells (>150 mm) of mixed-layer species (Globigerinoides ruber, Gs. sacculifer, Orbulina universa) were picked separately from a stratigraphic series of clay-rich samples recovered in a piston core taken atop Blake Ridge (northwestern Atlantic Ocean). Sample selection was guided by a foraminiferal δ18O record, which constrained the Last Glacial Maximum to ~100 cm core depth. Results support a diagenetic mechanism as glassy shells yield 14C ages that average ~2,000 ± 100 years younger than frosty shells from the same samples. Further, average δ13C of glassy shells is 0.6 ± 0.1‰ lower than that of frosty shells. Our findings indicate that 14C ages are artificially elevated by the dissolution of previously deposited ("old") carbonate and its subsequent reprecipitation as secondary carbonate on younger foraminiferal shells at, and beneath, the seafloor - a phenomenon that has not been quantified prior to this study.

  2. Income disparities shape medical student specialty choice.

    PubMed

    Wilder, Venis; Dodoo, Martey S; Phillips, Robert L; Teevan, Bridget; Bazemore, Andrew W; Petterson, Stephen M; Xierali, Imam

    2010-09-15

    Currently, a gap of more than $135,000 separates the median annual subspecialist income from that of a primary care physician, yielding a $3.5 million difference in expected income over a lifetime. These income disparities dissuade medical students from selecting primary care and should be addressed to ensure sufficient patient access to primary care. PMID:20842986

  3. Gender Wage Disparities among the Highly Educated

    ERIC Educational Resources Information Center

    Black, Dan A.; Haviland, Amelia M.; Sanders, Seth G.; Taylor, Lowell J.

    2008-01-01

    We examine gender wage disparities for four groups of college-educated women--black, Hispanic, Asian, and non-Hispanic white--using the National Survey of College Graduates. Raw log wage gaps, relative to non-Hispanic white male counterparts, generally exceed -0.30. Estimated gaps decline to between -0.08 and -0.19 in nonparametric analyses that…

  4. Friction and the Intuition-Outcome Disparity

    ERIC Educational Resources Information Center

    Kalajian, Peter; Makarova, Maria

    2014-01-01

    Humans have evolved to follow their intuition, but as any high school physics teacher knows, relying on intuition often leads students to predict outcomes that are at odds with evidence. Over the years, we have attempted to make this intuition-outcome disparity a central theme running throughout our physics classes, with limited success. Part of…

  5. Teachers' Voices 2: Teaching Disparate Learner Groups.

    ERIC Educational Resources Information Center

    Burns, Anne, Ed.; Hood, Susan, Ed.

    The collection of papers was written by teacher researchers from an adult migrant English program, and consists of reports and discussions of action research on teaching heterogeneous learner groups. Papers include: "Disparate Groups: Exploring Diversity in Practice through Collaborative Action Research" (Anne Burns, Susan Hood); "A Profile of…

  6. Stakeholder Payoff Matrix for Disparate Tradeoffs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the most difficult tasks decision makers face is to compare across disparate objectives. Evaluating environmental and economic tradeoffs is perhaps the most contentious of all decisions. Decision makers have to make comparisons with incomplete information and with nebulous value systems. Th...

  7. CDC Health Disparities and Inequalities Report--U.S. 2013

    MedlinePlus

    ... to Community Health Tribal Support Women's Health CDC Health Disparities & Inequalities Report (CHDIR) Recommend on Facebook Tweet Share Compartir ... Sheets 2011 Report More Information CDC Releases Second Health Disparities & Inequalities Report - United States, 2013 CDC and its partners ...

  8. 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.

  9. Access to Routine Immunization: A Comparative Analysis of Supply-Side Disparities between Northern and Southern Nigeria

    PubMed Central

    Eboreime, Ejemai; Abimbola, Seye; Bozzani, Fiammetta

    2015-01-01

    Background The available data on routine immunization in Nigeria show a disparity in coverage between Northern and Southern Nigeria, with the former performing worse. The effect of socio-cultural differences on health-seeking behaviour has been identified in the literature as the main cause of the disparity. Our study analyses the role of supply-side determinants, particularly access to services, in causing these disparities. Methods Using routine government data, we compared supply-side determinants of access in two Northern states with two Southern states. The states were identified using criteria-based purposive selection such that the comparisons were made between a low-coverage state in the South and a low-coverage state in the North as well as between a high-coverage state in the South and a high-coverage state in the North. Results Human resources and commodities at routine immunization service delivery points were generally insufficient for service delivery in both geographical regions. While disparities were evident between individual states irrespective of regional location, compared to the South, residents in Northern Nigeria were more likely to have vaccination service delivery points located within a 5km radius of their settlements. Conclusion Our findings suggest that regional supply-side disparities are not apparent, reinforcing the earlier reported socio-cultural explanations for disparities in routine immunization service uptake between Northern and Southern Nigeria. Nonetheless, improving routine immunisation coverage services require that there are available human resources and that health facilities are equitably distributed. PMID:26692215

  10. Using Community-Based Participatory Research to Ameliorate Cancer Disparities

    ERIC Educational Resources Information Center

    Gehlert, Sarah; Coleman, Robert

    2010-01-01

    Although much attention has been paid to health disparities in the past decades, interventions to ameliorate disparities have been largely unsuccessful. One reason is that the interventions have not been culturally tailored to the disparity populations whose problems they are meant to address. Community-engaged research has been successful in…

  11. Stigma and Racial/Ethnic HIV Disparities: Moving toward Resilience

    ERIC Educational Resources Information Center

    Earnshaw, Valerie A.; Bogart, Laura M.; Dovidio, John F.; Williams, David R.

    2013-01-01

    Prior research suggests that stigma plays a role in racial/ethnic health disparities. However, there is limited understanding about the mechanisms by which stigma contributes to HIV-related disparities in risk, incidence and screening, treatment, and survival and what can be done to reduce the impact of stigma on these disparities. We introduce…

  12. Urban-Rural Disparities in Injury Mortality in China, 2006

    ERIC Educational Resources Information Center

    Hu, Guoqing; Baker, Susan P.; Baker, Timothy D.

    2010-01-01

    Context: Urban-rural disparity is an important issue for injury control in China. Details of the urban-rural disparities in fatal injuries have not been analyzed. Purpose: To target key injury causes that most contribute to the urban-rural disparity, we decomposed total urban-rural differences in 2006 injury mortality by gender, age, and cause.…

  13. 41 CFR 60-3.11 - Disparate treatment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Disparate treatment. 60-3... treatment. The principles of disparate or unequal treatment must be distinguished from the concepts of..., or members have not been subjected to that standard. Disparate treatment occurs where members of...

  14. 41 CFR 60-3.11 - Disparate treatment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Disparate treatment. 60... treatment. The principles of disparate or unequal treatment must be distinguished from the concepts of..., or members have not been subjected to that standard. Disparate treatment occurs where members of...

  15. 41 CFR 60-3.11 - Disparate treatment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Disparate treatment. 60... treatment. The principles of disparate or unequal treatment must be distinguished from the concepts of..., or members have not been subjected to that standard. Disparate treatment occurs where members of...

  16. 41 CFR 60-3.11 - Disparate treatment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Disparate treatment. 60-3... treatment. The principles of disparate or unequal treatment must be distinguished from the concepts of..., or members have not been subjected to that standard. Disparate treatment occurs where members of...

  17. 41 CFR 60-3.11 - Disparate treatment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Disparate treatment. 60-3... treatment. The principles of disparate or unequal treatment must be distinguished from the concepts of..., or members have not been subjected to that standard. Disparate treatment occurs where members of...

  18. Gradients of relative disparity underlie the perceived slant of stereoscopic surfaces.

    PubMed

    Wardle, Susan G; Gillam, Barbara J

    2016-01-01

    Perceived stereoscopic slant around a vertical axis is strongly underestimated for isolated surfaces, suggesting that neither uniocular image compression nor linear gradients of absolute disparity are very effective cues. However, slant increases to a level close to geometric prediction if gradients of relative disparity are introduced, for example by placing flanking frontal-parallel surfaces at the horizontal boundaries of the slanted surface. Here we examine the mechanisms underlying this slant enhancement by manipulating properties of the slanted surface or the flanking surfaces. Perceived slant was measured using a probe bias method. In Experiment 1, an outlined surface and a randomly textured surface showed similar slant underestimation when presented in isolation, but the enhancement in slant produced by flankers was significantly greater for the textured surface. In Experiment 2, we degraded the relative disparity gradient by (a) reducing overall texture density, (b) reducing flanker width, or (c) adding disparity noise to the flankers. Density had no effect while adding noise to the flankers, or reducing their width significantly decreased perceived slant of the central surface. These results support the view that the enhancement of slant produced by adding flanking surfaces is attributable to the presence of a relative disparity gradient and that the flanker effect can spread to regions of the surface not directly above or below the gradient. PMID:26998800

  19. 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

  20. 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.

  1. 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.

  2. Molecular Gas Sensing Below Parts Per Trillion: Radiocarbon-Dioxide Optical Detection

    NASA Astrophysics Data System (ADS)

    Galli, I.; Bartalini, S.; Borri, S.; Cancio, P.; Mazzotti, D.; de Natale, P.; Giusfredi, G.

    2011-12-01

    Radiocarbon (C14) concentrations at a 43 parts-per-quadrillion level are measured by using saturated-absorption cavity ringdown spectroscopy by exciting radiocarbon-dioxide (C14O216) molecules at the 4.5μm 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 C14-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. 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.

  4. 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.

  5. Lung Cancer Treatment Disparities in China: A Question in Need of an Answer

    PubMed Central

    Yang, Lu-Lu; Zhang, Xu-Chao; Yang, Xue-Ning; Yang, Jin-Ji; Wang, Zhen; Chen, Hua-Jun; Yan, Hong-Hong; Xu, Chong-Rui; Guan, Ji-Lin; He, Yan-Yan; Zhong, Wen-Zhao; An, She-Juan

    2014-01-01

    Background. Substantial progress has been made in the treatment of malignancies in the People’s Republic of China in recent years. The goal of this study was to identify the extent to which national treatment guidelines are being used to customize patient care in lung cancer and to analyze the reasons for treatment disparities. Methods. Patient characteristics and treatments were investigated retrospectively for the period from October 2004 to January 2013 using the outpatient database of the Guangdong Lung Cancer Institute (GLCI) in China. Results. A total of 2,535 outpatients with lung cancer were studied in this retrospective analysis. The treatment disparity was 45.3%. Overall, 20.6% of patients with stage I non-small cell lung cancer (NSCLC) were overtreated, and 20.1% of stage II patients were undertreated. Only 19.6% of stage IIIA patients and 30.7% of stage IIIB patients underwent the recommended combination of chemotherapy and radiotherapy, respectively. For advanced NSCLC, the greatest treatment disparity appeared in the second-line setting and beyond. Patients who were positive for epidermal growth factor receptor (EGFR) and receiving EGFR tyrosine kinase inhibitors experienced significant prolongation of survival compared with patients who were EGFR negative or whose EGFR mutation status was unknown (hazard ratio: 0.79; p = .037). The treatment disparities were significantly larger among patients aged younger than 65 years and in patients from developing regions compared with patients aged 65 years and older and from developed regions, respectively (p < .001, p = .046). The difference in treatment disparity was statistically significant between GLCI and other hospitals (p < .001). Conclusion. This retrospective study of a large number of patients from an outpatient oncology database demonstrated large disparities in the treatment of lung cancer in China. It is important to develop a new guideline for recommendations that are based on resource

  6. PREVALENCE OF Entamoeba histolytica/Entamoeba dispar IN THE CITY OF CAMPINA GRANDE, IN NORTHEASTERN BRAZIL

    PubMed Central

    Silva, Maria Teresa Nascimento; Santana, José Valfrido; Bragagnoli, Gérson; Marinho, Alexandre Magno da Nóbrega; Malagueño, Elizabeth

    2014-01-01

    There is a clear need to perform epidemiological studies to find the true prevalence of Entamoeba histolytica around the world. The evaluation of this prevalence has been hindered by the existence of two different species which are morphologically identical, but genetically different, namely E. histolytica, which causes amebiasis, and E. dispar, which is non-pathogenic. In Brazil, the E. dispar has been detected in communities in the Southeastern (SE) and Northeastern (NE) regions with poor sanitation. However, individuals infected with E. histolytica have been identified in other regions. There is an absence of reports on the prevalence of these parasites in the state of Paraíba, which also has areas with poor sanitary conditions where a high prevalence of the E. histolytica/E. dispar complex has been detected in children from urban slums. The present study evaluated the prevalence of E. histolytica and E. dispar in 1,195 asymptomatic children between two and 10 years of age, living in a sprawling urban slum in Campina Grande, in the state of Paraíba, in Northeastern Brazil. These children were examined and their feces samples were analyzed microscopically. A total of 553 children tested positive for the E. histolytica/E. dispar complex, and 456 of the positive samples were tested with the E. histolytica II® ELISA kit. All 456 samples were negative for the presence of the adhesin E. histolytica specific antigen. The evidence suggests that in this community E. histolytica is absent and E. dispar is the dominant species. PMID:25229229

  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. 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.

  9. Confronting Health Disparities: Latin American Social Medicine in Venezuela

    PubMed Central

    Mantini-Briggs, Clara

    2009-01-01

    Objectives. We explored the emergence and effectiveness of Venezuela's Misión Barrio Adentro, “Inside the Neighborhood Mission,” a program designed to improve access to health care among underserved residents of the country, hoping to draw lessons to apply to future attempts to address acute health disparities. Methods. We conducted our study in 3 capital-region neighborhoods, 2 small cities, and 2 rural areas, combining systematic observations with interviews of 221 residents, 41 health professionals, and 28 government officials. We surveyed 177 female and 91 male heads of household. Results. Interviews suggested that Misión Barrio Adentro emerged from creative interactions between policymakers, clinicians, community workers, and residents, adopting flexible, problem-solving strategies. In addition, data indicated that egalitarian physician–patient relationships and the direct involvement of local health committees overcame distrust and generated popular support for the program. Media and opposition antagonism complicated physicians’ lives and clinical practices but heightened the program's visibility. Conclusions. Top-down and bottom-up efforts are less effective than “horizontal” collaborations between professionals and residents in underserved communities. Direct, local involvement can generate creative and dynamic efforts to address acute health disparities in these areas. PMID:19150916

  10. [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. PMID:15131987

  11. 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.

  12. 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.

  13. 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. PMID:17774077

  14. 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.

  15. 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

  16. Maps showing locations and descriptions of radiocarbon-dated samples from central and northern California

    USGS Publications Warehouse

    Price, Carol A.

    1982-01-01

    This compilation includes radiocarbon dates and other pertinent information about samples from northern and central California, principally north of latitude 36°, drawn largely from Radiocarbon, Science, unpublished data of U.S. Geological Survey geologists, and other published and unpublished data brought to the author's attention as of January 1981. It includes a location map, several tables, and two lists of sources that contain further information about the samples. This compilation is intended as a progress report rather than a complete survey of the literature.

  17. 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...

  18. 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.

  19. Measuring trends in racial/ ethnic health care disparities.

    PubMed

    Lê Cook, Benjamin; McGuire, Thomas G; Zuvekas, Samuel H

    2009-02-01

    Monitoring disparities over time is complicated by the varying disparity definitions applied in the literature. This study used data from the 1996-2005 Medical Expenditure Panel Survey (MEPS) to compare trends in disparities by three definitions of racial/ethnic disparities and to assess the influence of changes in socioeconomic status (SES) among racial/ethnic minorities on disparity trends. This study prefers the Institute of Medicine's (IOM) definition, which adjusts for health status but allows for mediation of racial/ethnic disparities through SES factors. Black-White disparities in having an office-based or outpatient visit and medical expenditure were roughly constant and Hispanic-White disparities increased for office-based or outpatient visits and for medical expenditure between 1996-1997 and 2004-2005. Estimates based on the independent effect of race/ethnicity were the most conservative accounting of disparities and disparity trends, underlining the importance of the role of SES mediation in the study of trends in disparities. PMID:18796581

  20. Disparity in motorcycle helmet use in Thailand

    PubMed Central

    2013-01-01

    The dispersion of motorcycle related injuries and deaths might be a result of disparity in motorcycle helmet use. This study uses national roadside survey data, injury sentinel surveillance data and other national data sets in 2010 of Thailand, a country with high mortality related to motorcycle injuries, to explore the disparity in helmet use, explanatory factors of the disparity. It also assessed potential agreement and correlation between helmet use rate reported by the roadside survey and the injury sentinel surveillance. This report revealed helmet use rate of 43.7%(95% CI:43.6,43.9) nationwide with the highest rate (81.8%; 95% CI: 44.0,46.4) in Bangkok. Helmet use rate in drivers (53.3%; 95% CI: 53.2,53.8) was 2.5 times higher than that in passengers (19.3%; 95% CI:18.9,19.7). In relative terms (highest-to-lowest ratio,HLR), geographical disparity in helmet use was found to be higher in passengers (HLR=28.5). Law enforcement activities as indicated by the conviction rate of motorcyclists were significantly associated with the helmet use rate (spline regression coefficient = 3.90, 95% CI: 0.48,7.33). Together with the finding of HLR for conviction rate of 87.24, it is suggested that more equitable improvement in helmet use could be achieved by more equitable distribution of the police force. Finally, we found poor correlation (r=0.01; p value = 0.76) and no agreement (difference = 34.29%; 95% CI:13.48%, 55.09%) between roadside survey and injury sentinel surveillance in estimating helmet use rate. These findings should be considered a warning for employing injury surveillance to monitor policy implementation of helmet use. PMID:24119233

  1. Socioeconomic Disparities and Health: Impacts and Pathways

    PubMed Central

    Kondo, Naoki

    2012-01-01

    Growing socioeconomic disparity is a global concern, as it could affect population health. The author and colleagues have investigated the health impacts of socioeconomic disparities as well as the pathways that underlie those disparities. Our meta-analysis found that a large population has risks of mortality and poor self-rated health that are attributable to income inequality. The study results also suggested the existence of threshold effects (ie, a threshold of income inequality over which the adverse impacts on health increase), period effects (ie, the potential for larger impacts in later years, specifically after the 1990s), and lag effects between income inequality and health outcomes. Our other studies using Japanese national representative survey data and a large-scale cohort study of Japanese older adults (AGES cohort) support the relative deprivation hypothesis, namely, that invidious social comparisons arising from relative deprivation in an unequal society adversely affect health. A study with a natural experiment design found that the socioeconomic gradient in self-rated health might actually have become shallower after the 1997–98 economic crisis in Japan, due to smaller health improvements among middle-class white-collar workers and middle/upper-income workers. In conclusion, income inequality might have adverse impacts on individual health, and psychosocial stress due to relative deprivation may partially explain those impacts. Any study of the effects of macroeconomic fluctuations on health disparities should also consider multiple potential pathways, including expanding income inequality, changes in the labor market, and erosion of social capital. Further studies are needed to attain a better understanding of the social determinants of health in a rapidly changing society. PMID:22156290

  2. Partitioning contrast or luminance disparity into perceived intensity and rotation.

    PubMed

    Hetley, Richard S; Stine, Wm Wren

    2011-01-01

    While most of the work on stereopsis focuses on geometric disparities, humans also respond to intensity (contrast or luminance) disparities in the absence of geometric disparities. A rectangular-wave grating viewed with an intensity disparity engenders two perceptions: a perceived intensity, and a perceived rotation of the individual bars of the grating (the Venetian blind effect). Measuring perceived intensity and perceived rotation in gratings with intensity disparities, we found that the two degrees of freedom from the intensities presented to each eye are conserved in the form of two perceptions: perceived intensity is related to the sum of the grating intensities and perceived rotation is related to the difference. Perceived rotation as a function of intensity disparity was then modeled as a simple difference in the neural response of each eye. Perceived contrast and brightness as a function of intensity disparity were modeled using the two-stage gain-control model. PMID:21864458

  3. 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. PMID:25494527

  4. 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.

  5. Trends in kidney transplantation rates and disparities.

    PubMed Central

    Stolzmann, Kelly L.; Bautista, Leonelo E.; Gangnon, Ronald E.; McElroy, Jane A.; Becker, Bryan N.; Remington, Patrick L.

    2007-01-01

    OBJECTIVE: To examine the likelihood of transplantation and trends over time among persons with end-stage renal disease (ESRD) in Wisconsin. METHODS: We examined the influence of patient- and community-level characteristics on the rate of kidney transplantation in Wisconsin among 22,387 patients diagnosed with ESRD between January 1, 1982 and October 30, 2005. We grouped patients by the year of ESRD onset in order to model the change in transplantation rates over time. RESULTS: After multivariate adjustment, all other racial groups were significantly less likely to be transplanted compared with whites, and the racial disparity increased over calendar time. Older patients were less likely to be transplanted in all periods. Higher community income and education level and a greater distance from patients' residence to the nearest dialysis center significantly increased the likelihood of transplantation. Males also had a significantly higher rate of transplantation than females. CONCLUSION: These results demonstrate a growing disparity in transplantation rates by demographic characteristics and a consistent disparity in transplantation by socioeconomic characteristics. Future studies should focus on identifying specific barriers to transplantation among different subpopulations in order to target effective interventions. PMID:17722672

  6. 3D camera tracking from disparity images

    NASA Astrophysics Data System (ADS)

    Kim, Kiyoung; Woo, Woontack

    2005-07-01

    In this paper, we propose a robust camera tracking method that uses disparity images computed from known parameters of 3D camera and multiple epipolar constraints. We assume that baselines between lenses in 3D camera and intrinsic parameters are known. The proposed method reduces camera motion uncertainty encountered during camera tracking. Specifically, we first obtain corresponding feature points between initial lenses using normalized correlation method. In conjunction with matching features, we get disparity images. When the camera moves, the corresponding feature points, obtained from each lens of 3D camera, are robustly tracked via Kanade-Lukas-Tomasi (KLT) tracking algorithm. Secondly, relative pose parameters of each lens are calculated via Essential matrices. Essential matrices are computed from Fundamental matrix calculated using normalized 8-point algorithm with RANSAC scheme. Then, we determine scale factor of translation matrix by d-motion. This is required because the camera motion obtained from Essential matrix is up to scale. Finally, we optimize camera motion using multiple epipolar constraints between lenses and d-motion constraints computed from disparity images. The proposed method can be widely adopted in Augmented Reality (AR) applications, 3D reconstruction using 3D camera, and fine surveillance systems which not only need depth information, but also camera motion parameters in real-time.

  7. Optimal disparity estimation in natural stereo images

    PubMed Central

    Burge, Johannes; Geisler, Wilson S.

    2014-01-01

    A great challenge of systems neuroscience is to understand the computations that underlie perceptual constancies, the ability to represent behaviorally relevant stimulus properties as constant even when irrelevant stimulus properties vary. As signals proceed through the visual system, neural states become more selective for properties of the environment, and more invariant to irrelevant features of the retinal images. Here, we describe a method for determining the computations that perform these transformations optimally, and apply it to the specific computational task of estimating a powerful depth cue: binocular disparity. We simultaneously determine the optimal receptive field population for encoding natural stereo images of locally planar surfaces and the optimal nonlinear units for decoding the population responses into estimates of disparity. The optimal processing predicts well-established properties of neurons in cortex. Estimation performance parallels important aspects of human performance. Thus, by analyzing the photoreceptor responses to natural images, we provide a normative account of the neurophysiology and psychophysics of absolute disparity processing. Critically, the optimal processing rules are not arbitrarily chosen to match the properties of neurophysiological processing, nor are they fit to match behavioral performance. Rather, they are dictated by the task-relevant statistical properties of complex natural stimuli. Our approach reveals how selective invariant tuning—especially for properties not trivially available in the retinal images—could be implemented in neural systems to maximize performance in particular tasks. PMID:24492596

  8. Scalable Combinatorial Tools for Health Disparities Research

    PubMed Central

    Langston, Michael A.; Levine, Robert S.; Kilbourne, Barbara J.; Rogers, Gary L.; Kershenbaum, Anne D.; Baktash, Suzanne H.; Coughlin, Steven S.; Saxton, Arnold M.; Agboto, Vincent K.; Hood, Darryl B.; Litchveld, Maureen Y.; Oyana, Tonny J.; Matthews-Juarez, Patricia; Juarez, Paul D.

    2014-01-01

    Despite staggering investments made in unraveling the human genome, current estimates suggest that as much as 90% of the variance in cancer and chronic diseases can be attributed to factors outside an individual’s genetic endowment, particularly to environmental exposures experienced across his or her life course. New analytical approaches are clearly required as investigators turn to complicated systems theory and ecological, place-based and life-history perspectives in order to understand more clearly the relationships between social determinants, environmental exposures and health disparities. While traditional data analysis techniques remain foundational to health disparities research, they are easily overwhelmed by the ever-increasing size and heterogeneity of available data needed to illuminate latent gene x environment interactions. This has prompted the adaptation and application of scalable combinatorial methods, many from genome science research, to the study of population health. Most of these powerful tools are algorithmically sophisticated, highly automated and mathematically abstract. Their utility motivates the main theme of this paper, which is to describe real applications of innovative transdisciplinary models and analyses in an effort to help move the research community closer toward identifying the causal mechanisms and associated environmental contexts underlying health disparities. The public health exposome is used as a contemporary focus for addressing the complex nature of this subject. PMID:25310540

  9. 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.

  10. 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.

  11. 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.

  12. Health disparities and gaps in school readiness.

    PubMed

    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 health problems and health-related behaviors that affect children's behavioral and cognitive readiness for school. If a health problem is to affect the readiness gap, it must affect many children, it must be linked to academic performance or behavior problems, and it must show a racial disparity either in its prevalence or in its effects. The author focuses not only on the black-white gap in health status but also on the poor-nonpoor gap because black children tend to be poorer than white children. The health conditions Currie considers seriously impair cognitive skills and behavior in individual children. But most explain little of the overall racial gap in school readiness. Still, the cumulative effect of health differentials summed over all conditions is significant. Currie's rough calculation is that racial differences in health conditions and in maternal health and behaviors together may account for as much as a quarter of the racial gap in school readiness. Currie scrutinizes several policy steps to lessen racial and socioeconomic disparities in children's health and to begin to close the readiness gap. Increasing poor children's eligibility for Medicaid and state child health insurance is unlikely to be effective because most poor children are already eligible for public insurance. The problem is that many are not enrolled. Even increasing enrollment may not work: socioeconomic disparities in health persist in Canada and the United Kingdom despite universal public health insurance. The author finds more promise in strengthening early childhood programs with a built-in health component, like Head Start; family

  13. 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

  14. 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. PMID:27508413

  15. Cost Effectiveness of Colorectal Cancer Screening Interventions with Their Effects on Health Disparity Being Considered

    PubMed Central

    Lee, Kwang-Sig; Park, Eun-Cheol

    2016-01-01

    Purpose The purpose of this study was to evaluate the cost effectiveness of colorectal cancer screening interventions with their effects on health disparity being considered. Materials and Methods Markov cohort simulation was conducted with the cycle/duration of 1/40 year(s). Data came from the results of randomized trials and others. Participants were hypothetical cohorts aged 50 years as of year 2013 in 16 Korean provinces. The interventions until the age of 80 were annual organized fecal occult blood test (FOBT) (standard screening), annual FOBT with basic reminders for provinces with higher mortalities than the national average (targeted reminder) and annual FOBT with basic/enhanced reminders for all provinces (universal reminder 1 and 2). The comparison was non-screening, the outcome was quality-adjusted life years, and only medical costs for screening and treatment were considered from a societal perspective. The Atkinson incremental cost effectiveness ratio (Atkinson ICER), the incremental cost effectiveness ratio adjusted by the Atkinson Inequality Index, was used to evaluate the cost effectiveness of the four interventions with their impacts on regional health disparity being considered. Results Health disparity was smallest (or greatest) in non-screening (or the standard screening). The targeted reminder had smaller health disparity, and smaller Atkinson ICER with respect to standard screening, than did the universal reminder 1 and 2. Conclusion The targeted reminder might be more cost effective than the universal reminders with their effects on health disparity being considered. This study helps to develop promotional effort for colorectal cancer screening with both the greatest cost effectiveness and the smallest health disparity PMID:26727714

  16. Functional Architecture for Disparity in Macaque Inferior Temporal Cortex and Its Relationship to the Architecture for Faces, Color, Scenes, and Visual Field

    PubMed Central

    Verhoef, Bram-Ernst; Bohon, Kaitlin S.

    2015-01-01

    Binocular disparity is a powerful depth cue for object perception. The computations for object vision culminate in inferior temporal cortex (IT), but the functional organization for disparity in IT is unknown. Here we addressed this question by measuring fMRI responses in alert monkeys to stimuli that appeared in front of (near), behind (far), or at the fixation plane. We discovered three regions that showed preferential responses for near and far stimuli, relative to zero-disparity stimuli at the fixation plane. These “near/far” disparity-biased regions were located within dorsal IT, as predicted by microelectrode studies, and on the posterior inferotemporal gyrus. In a second analysis, we instead compared responses to near stimuli with responses to far stimuli and discovered a separate network of “near” disparity-biased regions that extended along the crest of the superior temporal sulcus. We also measured in the same animals fMRI responses to faces, scenes, color, and checkerboard annuli at different visual field eccentricities. Disparity-biased regions defined in either analysis did not show a color bias, suggesting that disparity and color contribute to different computations within IT. Scene-biased regions responded preferentially to near and far stimuli (compared with stimuli without disparity) and had a peripheral visual field bias, whereas face patches had a marked near bias and a central visual field bias. These results support the idea that IT is organized by a coarse eccentricity map, and show that disparity likely contributes to computations associated with both central (face processing) and peripheral (scene processing) visual field biases, but likely does not contribute much to computations within IT that are implicated in processing color. PMID:25926470

  17. Functional architecture for disparity in macaque inferior temporal cortex and its relationship to the architecture for faces, color, scenes, and visual field.

    PubMed

    Verhoef, Bram-Ernst; Bohon, Kaitlin S; Conway, Bevil R

    2015-04-29

    Binocular disparity is a powerful depth cue for object perception. The computations for object vision culminate in inferior temporal cortex (IT), but the functional organization for disparity in IT is unknown. Here we addressed this question by measuring fMRI responses in alert monkeys to stimuli that appeared in front of (near), behind (far), or at the fixation plane. We discovered three regions that showed preferential responses for near and far stimuli, relative to zero-disparity stimuli at the fixation plane. These "near/far" disparity-biased regions were located within dorsal IT, as predicted by microelectrode studies, and on the posterior inferotemporal gyrus. In a second analysis, we instead compared responses to near stimuli with responses to far stimuli and discovered a separate network of "near" disparity-biased regions that extended along the crest of the superior temporal sulcus. We also measured in the same animals fMRI responses to faces, scenes, color, and checkerboard annuli at different visual field eccentricities. Disparity-biased regions defined in either analysis did not show a color bias, suggesting that disparity and color contribute to different computations within IT. Scene-biased regions responded preferentially to near and far stimuli (compared with stimuli without disparity) and had a peripheral visual field bias, whereas face patches had a marked near bias and a central visual field bias. These results support the idea that IT is organized by a coarse eccentricity map, and show that disparity likely contributes to computations associated with both central (face processing) and peripheral (scene processing) visual field biases, but likely does not contribute much to computations within IT that are implicated in processing color. PMID:25926470

  18. Radiocarbon evidence for a smaller oceanic carbon dioxide sink than previously believed

    NASA Astrophysics Data System (ADS)

    Hesshaimer, Vago; Heimann, Martin; Levin, Ingeborg

    1994-07-01

    RADIOCARBON produced naturally in the upper atmosphere or arti-ficially during nuclear weapons testing is the main tracer used to validate models of oceanic carbon cycling, in particular the exchange of carbon dioxide with the atmosphere1-3 and the mixing parameters within the ocean itself4-7. Here we test the overall consistency of exchange fluxes between all relevant compartments in a simple model of the global carbon cycle, using measurements of the long-term tropospheric CO2 concentration8 and radiocarbon composition9-12, the bomb 14C inventory in the stratosphere13,14 and a compilation of bomb detonation dates and strengths15. We find that to balance the budget, we must invoke an extra source to account for 25% of the generally accepted uptake of bomb 14C by the oceans3. The strength of this source decreases from 1970 onwards, with a characteristic timescale similar to that of the ocean uptake. Significant radiocarbon transport from the remote high stratosphere and significantly reduced uptake of bomb 14C by the biosphere can both be ruled out by observational constraints. We therefore conclude that the global oceanic bomb 14C inventory should be revised downwards. A smaller oceanic bomb 14C inventory also implies a smaller oceanic radiocarbon penetration depth16, which in turn implies that the oceans take up 25% less anthropogenic CO2 than had previously been believed.

  19. 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.

  20. ORIGIN OF CARBONACEOUS PARTICLES IN AMERICAN CITIES: RESULTS OF RADIOCARBON 'DATING' AND CHEMICAL CHARACTERIZATION

    EPA Science Inventory

    During the past three years radiocarbon assay has emerged as a primary tool in the quantitative assignment of sources of urban and rural particulate pollution. Its use in several major field studies has come about because of its excellent (fossil/biogenic) discriminating power, b...

  1. Revised age of deglaciation of Lake Emma based on new radiocarbon and macrofossil analyses

    NASA Astrophysics Data System (ADS)

    Elias, Scott A.; Carrara, Paul E.; Toolin, L. J.; Jull, A. J. T.

    1991-11-01

    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.

  2. 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…

  3. RADIOCARBON MEASUREMENTS ON PM 2.5 AMBIENT AEROSOL FROM NASHVILLE, TN

    EPA Science Inventory

    Radiocarbon (Carbon-14) 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...

  4. 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...

  5. High precise measurements of cosmogenic radiocarbon abundance by complex of scintillation equipments

    NASA Technical Reports Server (NTRS)

    Kocharov, G. E.; Metskvarishvili, R. Y.; Tsereteli, S. L.

    1985-01-01

    The main characteristics of scintillation equipments which enable the measurements of radiocarbon content with high accuracy of 0.2 to 0.3% were considered. The complex of scintillation devices operated very well for the last 15 years and allowed the investigation of the temporal variation of solar activity and intensity of cosmic rays for the last 300 years.

  6. Extraneous carbon assessment in ultra-microscale radiocarbon analysis using benzene polycarboxylic acids (BPCA)

    NASA Astrophysics Data System (ADS)

    Hanke, Ulrich M.; McIntyre, Cameron P.; Schmidt, Michael W. I.; Wacker, Lukas; Eglinton, Timothy I.

    2016-04-01

    Measurements of the natural abundance of radiocarbon (14C) concentrations in inorganic and organic carbon-containing materials can be used to investigate their date of origin. Particularly, the biogeochemical cycling of specific compounds in the environment may be investigated applying molecular marker analyses. However, the isolation of specific molecules from environmental matrices requires a complex processing procedure resulting in small sample sizes that often contain less than 30 μg C. Such small samples are sensitive to extraneous carbon (Cex) that is introduced during the purification of the compounds (Shah and Pearson, 2007). We present a thorough radiocarbon blank assessment for benzene polycarboxylic acids (BPCA), a proxy for combustion products that are formed during the oxidative degradation of condensed polyaromatic structures (Wiedemeier et al, in press). The extraneous carbon assessment includes reference material for (1) chemical extraction, (2) preparative liquid chromatography (3) wet chemical oxidation which are subsequently measured with gas ion source AMS (Accelerator Mass Spectrometer, 5-100 μg C). We always use pairs of reference materials, radiocarbon depleted (14Cfossil) and modern (14Cmodern) to determine the fraction modern (F14C) of Cex.Our results include detailed information about the quantification of Cex in radiocarbon molecular marker analysis using BPCA. Error propagation calculations indicate that ultra-microscale samples (20-30 μg) are feasible with uncertainties of less than 10 %. Calculations of the constant contamination reveal important information about the source (F14C) and mass (μg) of Cex (Wacker and Christl, 2011) for each sub procedure. An external correction of compound specific radiocarbon data is essential for robust results that allow for a high degree of confidence in the 14C results. References Shah and Pearson, 2007. Ultra-microscale (5-25μg C) analysis of individual lipids by 14C AMS: Assessment and

  7. Biogenic contribution to PM-2.5 ambient aerosol from radiocarbon measurements

    NASA Astrophysics Data System (ADS)

    Lewis, C.; Klouda, G.; Ellenson, W.

    2003-04-01

    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 (14C) measurements provide a means to quantify the biogenic fraction of any carbon-containing sample of ambient aerosol. In the absence of an impact from biomass burning (e.g., during summertime) such measurements can provide an estimate of the contribution of biogenic secondary organic aerosol, from biogenic volatile organic compound precursors. Radiocarbon results for 11.5-h PM-2.5 samples collected near Nashville, Tennessee, USA, during summer 1999 will be presented. On average the measured biogenic fraction was surprisingly large (more than half), with the average biogenic fraction for night samples being only slightly smaller than for day samples. Discussion will include (a) description of the radiocarbon methodology, (b) use of radiocarbon measurements on local vegetation and fuel samples as calibration data, (c) concurrent measurements of organic carbon and elemental carbon ambient concentrations, (d) assessment of organic aerosol sampling artifact through use of organic vapor denuders, variable face velocities, and filter extraction, and (e) comparison with published radiocarbon results obtained in Houston, Texas in a similar study. Disclaimer: This work has been funded wholly or in part by the United States Environmental Protection Agency under Interagency Agreement No. 13937923 to the National Institute of Standards and Technology, and Contract No. 68-D5-0049 to ManTech Environmental Tecnology, Inc. It has been subjected to Agency review and approved for publication.

  8. Marine radiocarbon reservoir age variation in Donax obesulus shells from northern Peru: late Holocene evidence for extended El Niño

    USGS Publications Warehouse

    Etayo-Cadavid, Miguel F.; Andrus, C. Fred T.; Jones, Kevin B.; Hodgins, Gregory W. L.; Sandweiss, Daniel H.; Uceda-Castillo, Sandiago; Quilter, Jeffrey

    2013-01-01

    For at least 6 m.y., El Niño events have posed the greatest environmental risk on the Peruvian coast. A better understanding of El Niño is essential for predicting future risk and growth in this tropical desert. To achieve this we analyzed archaeological and modern pre-bomb shells from the surf clam Donax for the radiocarbon reservoir effect (ΔR) to characterize late Holocene coastal upwelling conditions in northern Peru (8°14′S). Mean ΔR values from these shells suggest that modern upwelling conditions in this region were likely established between A.D. 539 and A.D. 1578. Our radiocarbon data suggest that upwelling conditions ca. A.D. 539 were less intense than those in modern times. The observed coastal water enrichment in 14C may be consequence of frequent strong El Niño events or extended El Niño–like conditions. These ΔR-inferred marine conditions are in agreement with proposed extended El Niño activity in proxy and archaeological records of ca. A.D. 475–530. Extended El Niño conditions have been linked to political destabilization, societal transformation, and collapse of the Moche civilization in northern Peru. A return to such conditions would have significant impacts on the dense population of this region today and in the near future.

  9. High-temporal resolution radiocarbon analyses of dissolved organic matter in soils from a mountainous and temperate ecosystem

    NASA Astrophysics Data System (ADS)

    van der Voort, Tessa Sophia; Graf Pannatier, Elisabeth; McIntyre, Cameron; Hagedorn, Frank; Eglinton, Timothy

    2016-04-01

    A better understanding of the stability and turnover of soil dissolved organic matter (DOM) is key in order to predict the behavior and response of this dynamic carbon pool to climate and land use change. Radiocarbon is increasingly used to determine carbon turnover in carbon cycle studies. However, due to the nature of radiocarbon measurement as well as complexity of in-situ DOM collection, little comprehensive radiocarbon and turnover data is currently available. This project combines a high-resolution temporal DOM sequence for a mountainous (podzol) and temperate (cambisol) forest ecosystem with additional bulk- and fraction-specific soil organic matter analyses. DOM was collected bi-weekly on two sites of the Long-Term Forest Ecosystem Research (LWF) program of the Swiss Federal Institute for Forest, Snow and Landscape research (WSL) at four depths, and measured for radiocarbon content. These initial results indicate bi-weekly variation in radiocarbon signatures over the summer season and a strong soil-type dependent pattern in DO14C trend. Overall, these initial radiocarbon results indicate that DOM dynamics are seasonally variable, and thus could potentially be sensitive to future climate change. Furthermore, the DO14C trend helps to better understand the trends as can be seen in the bulk 14C signature of the soil organic matter. Detailed radiocarbon investigations of soil DOM may yield key insights into the complex carbon transport dynamics in different soil systems and their potential behavior under climate change scenarios.

  10. Physicians' ethical responsibilities in addressing racial and ethnic healthcare disparities.

    PubMed Central

    Bostick, Nathan; Morin, Karine; Benjamin, Regina; Higginson, Daniel

    2006-01-01

    Patients belonging to racial and ethnic minority populations continue to receive lesser-quality healthcare relative to other patients, even when controlling for relevant demographic variables. Such disparities represent a significant challenge for physicians who are ethically committed to serving all patients equally, irrespective of personal characteristics. Accordingly, this report explores the ethical obligations of individual physicians and the medical profession as they pertain to racial and ethnic disparities in healthcare. To address these disparities, the AMA Council on Ethical and Judicial Affairs recommends that physicians customize the provision of medial care to meet the needs and preferences of individual patients. Moreover, physicians must learn to recognize racial and ethnic healthcare disparities and critically examine their own practices to ensure that inappropriate considerations do not affect clinical judgment. Physicians can also work to eliminate racial and ethnic healthcare disparities by encouraging diversity within the profession, continuing to investigate healthcare disparities, and supporting the development of appropriate quality measures. PMID:16916132

  11. Disparity modifications and the emotional effects of stereoscopic images

    NASA Astrophysics Data System (ADS)

    Kawai, Takashi; Atsuta, Daiki; Tomiyama, Yuya; Kim, Sanghyun; Morikawa, Hiroyuki; Mitsuya, Reiko; Häkkinen, Jukka

    2014-03-01

    This paper describes a study that focuses on disparity changes in emotional scenes of stereoscopic (3D) images, in which an examination of the effects on pleasant and arousal was carried out by adding binocular disparity to 2D images that evoke specific emotions, and applying disparity modification based on the disparity analysis of famous 3D movies. From the results of the experiment, for pleasant, a significant difference was found only for the main effect of the emotions. On the other hand, for arousal, there was a trend of increasing the evaluation values in the order 2D condition, 3D condition and 3D condition applied the disparity modification for happiness, surprise, and fear. This suggests the possibility that binocular disparity and the modification affect arousal.

  12. Ethnic and socioeconomic disparities in dermatology.

    PubMed

    Jackson, Chantal; Maibach, Howard

    2016-06-01

    Ethnic and socioeconomic disparities exist within healthcare. Specifically, minority group members experience more deleterious health outcomes than do majority group members. In this paper, we explore the factors that influence such variety, with a focus on the field of dermatology, in an attempt to understand the ways to improve minority group results. We also highlight how the prevalence of mental health issues within minority group and low socioeconomic status individuals can differentially influence dermatological disease states, such as the relationship between depression and psoriasis. PMID:26418077

  13. Understanding Racial/Ethnic Disparities in Youth Mental Health Services: Do Disparities Vary by Problem Type?

    ERIC Educational Resources Information Center

    Gudino, Omar G.; Lau, Anna S.; Yeh, May; McCabe, Kristen M.; Hough, Richard L.

    2009-01-01

    The authors examined racial/ethnic disparities in mental health service use based on problem type (internalizing/externalizing). A diverse sample of youth in contact with public sectors of care and their families provided reports of youth's symptoms and functional impairment during an initial interview. Specialty and school-based mental health…

  14. Optimal integration of shading and binocular disparity for depth perception.

    PubMed

    Lovell, Paul G; Bloj, Marina; Harris, Julie M

    2012-01-01

    We explore the relative utility of shape from shading and binocular disparity for depth perception. Ray-traced images either featured a smooth surface illuminated from above (shading-only) or were defined by small dots (disparity-only). Observers judged which of a pair of smoothly curved convex objects had most depth. The shading cue was around half as reliable as the rich disparity information for depth discrimination. Shading- and disparity-defined cues where combined by placing dots in the stimulus image, superimposed upon the shaded surface, resulting in veridical shading and binocular disparity. Independently varying the depth delivered by each channel allowed creation of conflicting disparity-defined and shading-defined depth. We manipulated the reliability of the disparity information by adding disparity noise. As noise levels in the disparity channel were increased, perceived depths and variances shifted toward those of the now more reliable shading cue. Several different models of cue combination were applied to the data. Perceived depths and variances were well predicted by a classic maximum likelihood estimator (MLE) model of cue integration, for all but one observer. We discuss the extent to which MLE is the most parsimonious model to account for observer performance. PMID:22214563

  15. Disparity modification in stereoscopic images for emotional enhancement

    NASA Astrophysics Data System (ADS)

    Kawai, Takashi; Atsuta, Daiki; Kim, Sanghyun; Häkkinen, Jukka

    2015-03-01

    This paper describes an experiment that focuses on disparity changes in emotional scenes of stereoscopic (3D) images, in which an examination of the effects on pleasant and arousal was carried out by adding binocular disparity to 2D images that evoke specific emotions, and applying disparity modification based on the disparity analysis of prominent 3D movies. From the results of the experiment, it was found that pleasant and arousal was increased by expanding 3D space to a certain level. In addition, pleasant gradually decreased and arousal gradually increased by expansion of 3D space above a certain level.

  16. The 2014 Minority Health and Health Disparities Grantees’ Conference

    PubMed Central

    Edberg, Mark; Hayes, Barbara E.; Montgomery-Rice, Valerie; Tchounwou, Paul B.

    2015-01-01

    Health disparities have been defined as a particular type of health difference closely linked with social, economic and/or environmental disadvantage. The National Institute on Minority Health and Health Disparities (NIMHD) at the National Institutes of Health, has a comprehensive portfolio of grants that fund scientific research to improve racial/ethnic minority health and eliminate health disparities. The 2014 Minority Health and Health Disparities Grantees’ Conference highlighted excellence and innovation in biological, environmental, sociocultural, clinical and behavioral research supported by NIMHD. This special issue of the International Journal of Environmental Research and Public Health includes peer-reviewed publications from investigators who participated in this conference.

  17. Underserved farmers with disabilities: designing an AgrAbility program to address health disparities.

    PubMed

    Hunter, Elizabeth G; Hancock, John; Weber, Carol; Simon, Marion

    2011-04-01

    Awareness of health disparities is crucial for individuals with disabilities to minimize additional health-related challenges. Adding rural residence and age to disability creates a triple threat in terms of potential health disparities. Kentucky AgrAbility is developing innovative new partnerships with the goal of expanding service provision to underserved populations with disabilities in Kentucky: women, minority, and Appalachian small farmers. Kentucky AgrAbility is evolving to include a more focused approach to the needs of underresourced and underserved regions and populations of farmers in Kentucky. Through new partnerships and a commitment to addressing potential health disparities, farmers and families who can benefit from AgrAbility services will be broadly identified. It is concluded that health disparities need to be recognized and addressed in all health care service provision and education. Kentucky AgrAbility is attempting to develop and implement an innovative, multidisciplinary team of partners with a goal of providing one of a kind service and education to all Kentucky farmers with disabilities. This includes underserved farmers who are at risk of not receiving the appropriate services due to limited resources and lack of awareness. PMID:21462022

  18. Swimming upstream: the challenges and rewards of evaluating efforts to address inequities and reduce health disparities.

    PubMed

    Hughes, Dana; Docto, Lindsay; Peters, Jessica; Lamb, Anne Kelsey; Brindis, Claire

    2013-06-01

    Racial and ethnic disparities in the health of Americans are widespread and persistent in the United States despite improvements in the health of Americans overall. Increasingly, strategies for reducing disparities have focused on addressing the factors that contribute to - if not fundamentally underlie - health disparities: social, economic, and environmental inequities, which limit access to resources and cause unhealthy exposures. As public health shifts to interventions that seek to improve the circumstances of disproportionately affected populations and achieve equity through policy change, alternative methods to evaluate these efforts are also required. This paper presents an example of such approaches to addressing asthma disparities through Regional Asthma Management and Prevention's (RAMP) programmatic efforts and an evaluation of these activities. The paper describes RAMP's targets and strategies, as well as the specific evaluation methods applied to each, including activity tracking, observations, surveys, key informant interviews, and case studies. Preliminary evaluation findings are presented, as are lessons learned about the efficacy of the evaluation design features - both its strengths and shortcomings. Findings discussed are intended to contribute to the growing literature that provides evidence for the application of emerging approaches to evaluation that reflect non-traditional public health and support others interested in expanding or replicating this work. PMID:23416287

  19. National and State-Specific Health Insurance Disparities for Adults in Same-Sex Relationships

    PubMed Central

    Blewett, Lynn A.

    2014-01-01

    Objectives. We examined national and state-specific disparities in health insurance coverage, specifically employer-sponsored insurance (ESI) coverage, for adults in same-sex relationships. Methods. We used data from the American Community Survey to identify adults (aged 25–64 years) in same-sex relationships (n = 31 947), married opposite-sex relationships (n = 3 060 711), and unmarried opposite-sex relationships (n = 259 147). We estimated multinomial logistic regression models and state-specific relative differences in ESI coverage with predictive margins. Results. Men and women in same-sex relationships were less likely to have ESI than were their married counterparts in opposite-sex relationships. We found ESI disparities among adults in same-sex relationships in every region, but we found the largest ESI gaps for men in the South and for women in the Midwest. ESI disparities were narrower in states that had extended legal same-sex marriage, civil unions, and broad domestic partnerships. Conclusions. Men and women in same-sex relationships experience disparities in health insurance coverage across the country, but residing in a state that recognizes legal same-sex marriage, civil unions, or broad domestic partnerships may improve access to ESI for same-sex spouses and domestic partners. PMID:24328616

  20. Racial and Ethnic Disparities in Breastfeeding

    PubMed Central

    Jones, Katherine M.; Queenan, John T.; Schulkin, Jay

    2015-01-01

    Abstract This article's aim is to review the literature on racial and ethnic disparities in breastfeeding rates and practices, address barriers to breastfeeding among minority women, conduct a systematic review of breastfeeding interventions, and provide obstetrician-gynecologists with recommendations on how they can help increase rates among minority women. In order to do so, the literature of racial and ethnic disparities in breastfeeding rates and barriers among minority women was reviewed, and a systematic review of breastfeeding interventions among minority women on PubMed and MEDLINE was conducted. Racial and ethnic minority women continue to have lower breastfeeding rates than white women and are not close to meeting the Healthy People 2020 goals. Minority women report many barriers to breastfeeding. Major efforts are still needed to improve breastfeeding initiation and duration rates among minority women in the United States. Obstetrician-gynecologists have a unique opportunity to promote and support breastfeeding through their clinical practices and public policy, and their efforts can have a meaningful impact on the future health of the mother and child. PMID:25831234

  1. Perspectives on disparities in depression care.

    PubMed

    Kristofco, Robert E; Stewart, Altha J; Vega, William

    2007-01-01

    Depression is a major public health problem and a leading cause of disability worldwide. Compounding the high rates of morbidity and mortality and treatment challenges associated with depression are the tremendous disparities in quality of mental health care that exist between the majority of the population and those of racial and ethnic minorities. Although more study data are available on depression care for African Americans than for other groups, racial and ethnic minorities overall are less likely than whites to receive an accurate diagnosis, to receive care according to evidence-based guidelines, and to receive an antidepressant upon diagnosis. Multiple factors contribute to these disparities, among them socioeconomic and cultural issues and prejudices among patients and health care providers. Closing the gap that exists between what depression care is and what depression care could be begins with clinicians' recognizing the relevance of culture to care. Opportunities exist within the broader context of medical education, including continuing medical education (CME), to prepare health care professionals to address the myriad issues related to managing depression. PMID:18085576

  2. Racial and ethnic disparities in breastfeeding.

    PubMed

    Jones, Katherine M; Power, Michael L; Queenan, John T; Schulkin, Jay

    2015-05-01

    This article's aim is to review the literature on racial and ethnic disparities in breastfeeding rates and practices, address barriers to breastfeeding among minority women, conduct a systematic review of breastfeeding interventions, and provide obstetrician-gynecologists with recommendations on how they can help increase rates among minority women. In order to do so, the literature of racial and ethnic disparities in breastfeeding rates and barriers among minority women was reviewed, and a systematic review of breastfeeding interventions among minority women on PubMed and MEDLINE was conducted. Racial and ethnic minority women continue to have lower breastfeeding rates than white women and are not close to meeting the Healthy People 2020 goals. Minority women report many barriers to breastfeeding. Major efforts are still needed to improve breastfeeding initiation and duration rates among minority women in the United States. Obstetrician-gynecologists have a unique opportunity to promote and support breastfeeding through their clinical practices and public policy, and their efforts can have a meaningful impact on the future health of the mother and child. PMID:25831234

  3. The academic advantage: gender disparities in patenting.

    PubMed

    Sugimoto, Cassidy R; Ni, Chaoqun; West, Jevin D; Larivière, Vincent

    2015-01-01

    We analyzed gender disparities in patenting by country, technological area, and type of assignee using the 4.6 million utility patents issued between 1976 and 2013 by the United States Patent and Trade Office (USPTO). Our analyses of fractionalized inventorships demonstrate that women's rate of patenting has increased from 2.7% of total patenting activity to 10.8% over the nearly 40-year period. Our results show that, in every technological area, female patenting is proportionally more likely to occur in academic institutions than in corporate or government environments. However, women's patents have a lower technological impact than that of men, and that gap is wider in the case of academic patents. We also provide evidence that patents to which women--and in particular academic women--contributed are associated with a higher number of International Patent Classification (IPC) codes and co-inventors than men. The policy implications of these disparities and academic setting advantages are discussed. PMID:26017626

  4. The Academic Advantage: Gender Disparities in Patenting

    PubMed Central

    Sugimoto, Cassidy R.; Ni, Chaoqun; West, Jevin D.; Larivière, Vincent

    2015-01-01

    We analyzed gender disparities in patenting by country, technological area, and type of assignee using the 4.6 million utility patents issued between 1976 and 2013 by the United States Patent and Trade Office (USPTO). Our analyses of fractionalized inventorships demonstrate that women’s rate of patenting has increased from 2.7% of total patenting activity to 10.8% over the nearly 40-year period. Our results show that, in every technological area, female patenting is proportionally more likely to occur in academic institutions than in corporate or government environments. However, women’s patents have a lower technological impact than that of men, and that gap is wider in the case of academic patents. We also provide evidence that patents to which women—and in particular academic women—contributed are associated with a higher number of International Patent Classification (IPC) codes and co-inventors than men. The policy implications of these disparities and academic setting advantages are discussed. PMID:26017626

  5. National newspaper coverage of minority health disparities.

    PubMed Central

    Amzel, Anouk; Ghosh, Chandak

    2007-01-01

    OBJECTIVES: To assess American newspaper coverage regarding racial and ethnic minority health disparities (MHDs). METHODS: LexisNexis was queried with specific word combinations to elicit all MHD articles printed in 257 newspapers from 2000-2004. The full texts were read and articles categorized by racial/ethnic group and specific MHD topics mentioned. RESULTS: In the five years from 2000-2004, 1188 MHD articles were published, representing 0.09% of all articles about health. Newspapers gave much attention to MHD when discussed in conferences and meetings and speeches by senior health officials and politicians. Cancer, cardiovascular disease and HIV/AIDS were most frequent among disease-specific mentions. Articles about African Americans comprised 60.4% of all race/ethnicity-mentioning articles. CONCLUSIONS: Despite the release of major organizational reports and the publication of many studies confirming the prevalence of MHD, few newspaper articles have been published explaining MHD to the public. Because of the general public's low rate of health literacy, the health world should collaborate with the media to present a consistent, simple message concerning gaps in care experienced by all racial/ethnic minority groups. In a time of consumer-directed healthcare, if Americans understand that MHDs exist, they may galvanize to advocate for disparity elimination and quality improvement. PMID:17987915

  6. The human face of health disparities.

    PubMed

    Green, Alexander R

    2003-01-01

    In the last 20 years, the issue of disparities in health between racial/ethnic groups has moved from the realm of common sense and anecdote to the realm of science. Hard, cold data now force us to consider what many had long taken for granted. Not only does health differ by race/ethnicity, but our health care system itself is deeply biased. From lack of diversity in the leadership and workforce, to ethnocentric systems of care, to biased clinical decision-making, the American health care system is geared to treat the majority, while the minority suffers. The photos shown here are of patients and scenes that recall some of the important landmarks in research on racial/ethnic disparities in health. The purpose is to put faces and humanity onto the numbers. While we now have great bodies of evidence upon which to lobby for change, in the end, each statistic still represents a personal tragedy or an individual triumph. PMID:12815077

  7. Ethnicity and Health Disparities in Alcohol Research

    PubMed Central

    Chartier, Karen; Caetano, Raul

    2010-01-01

    Recent advances in alcohol research continue to build our understanding of alcohol consumption and related consequences for U.S. ethnic minority groups. National surveys show variations across ethnicities in drinking, alcohol use disorders, alcohol problems, and treatment use. Higher rates of high-risk drinking among ethnic minorities are reported for Native Americans and Hispanics, although within-ethnic group differences (e.g., gender, age-group, and other subpopulations) also are evident for ethnicities. Whites and Native Americans have a greater risk for alcohol use disorders relative to other ethnic groups. However, once alcohol dependence occurs, Blacks and Hispanics experience higher rates than Whites of recurrent or persistent dependence. Furthermore, the consequences of drinking appear to be more profound for Native Americans, Hispanics, and Blacks. Disparities in alcohol treatment utilization are most apparent for Hispanics. Explanations for these differences are complex, likely affected by risky drinking behaviors, immigration experiences, racial/ethnic discrimination, economic and neighborhood disadvantage, and variations in alcohol-metabolizing genes. Research must maintain a systematic, strong, and growing focus on ethnic minorities. A more complete understanding of these effects for ethnic minority groups is needed to enable researchers to face the challenges of reducing and ultimately eliminating health disparities in the alcohol field. PMID:21209793

  8. Addressing Health Disparities in Chronic Kidney Disease

    PubMed Central

    Chan, Ta-Chien; Fan, I.-Chun; Liu, Michael Shi-Yung; Su, Ming-Daw; Chiang, Po-Huang

    2014-01-01

    According to the official health statistics, Taiwan has the highest prevalence of end stage renal disease (ESRD) in the world. Each year, around 60,000 ESRD patients in Taiwan consume 6% of the national insurance budget for dialysis treatment. The prevalence of chronic kidney disease (CKD) has been climbing during 2008–2012. However, the spatial disparities and clustering of CKD at the public health level have rarely been discussed. The aims of this study are to explore the possible population level risk factors and identify any clusters of CKD, using the national health insurance database. The results show that the ESRD prevalence in females is higher than that in males. ESRD medical expenditure constitutes 87% of total CKD medical expenditure. Pre-CKD and pre-ESRD disease management might slow the progression from CKD to ESRD. After applying ordinary least-squares regression, the percentages of high education status and the elderly in the townships are positively correlated with CKD prevalence. Geographically weighted regression and Local Moran’s I are used for identifying the clusters in southern Taiwan. The findings can be important evidence for earlier and targeted community interventions and reducing the health disparities of CKD. PMID:25514144

  9. How visual attention is modified by disparities and textures changes?

    NASA Astrophysics Data System (ADS)

    Khaustova, Dar'ya; Fournier, Jérome; Wyckens, Emmanuel; Le Meur, Olivier

    2013-03-01

    The 3D image/video quality of experience is a multidimensional concept that depends on 2D image quality, depth quantity and visual comfort. The relationship between these parameters is not yet clearly defined. From this perspective, we aim to understand how texture complexity, depth quantity and visual comfort influence the way people observe 3D content in comparison with 2D. Six scenes with different structural parameters were generated using Blender software. For these six scenes, the following parameters were modified: texture complexity and the amount of depth changing the camera baseline and the convergence distance at the shooting side. Our study was conducted using an eye-tracker and a 3DTV display. During the eye-tracking experiment, each observer freely examined images with different depth levels and texture complexities. To avoid memory bias, we ensured that each observer had only seen scene content once. Collected fixation data were used to build saliency maps and to analyze differences between 2D and 3D conditions. Our results show that the introduction of disparity shortened saccade length; however fixation durations remained unaffected. An analysis of the saliency maps did not reveal any differences between 2D and 3D conditions for the viewing duration of 20 s. When the whole period was divided into smaller intervals, we found that for the first 4 s the introduced disparity was conducive to the section of saliency regions. However, this contribution is quite minimal if the correlation between saliency maps is analyzed. Nevertheless, we did not find that discomfort (comfort) had any influence on visual attention. We believe that existing metrics and methods are depth insensitive and do not reveal such differences. Based on the analysis of heat maps and paired t-tests of inter-observer visual congruency values we deduced that the selected areas of interest depend on texture complexities.

  10. Applications of radiocarbon measurements in environmental studies at INFN-LABEC, Florence

    NASA Astrophysics Data System (ADS)

    Fedi, M.; Álvarez-Iglesias, P.; Caforio, L.; Calzolai, G.; Bernardoni, V.; Chiari, M.; Nava, S.; Taccetti, F.; Vecchi, R.

    2012-04-01

    Radiocarbon is one of the most widespread radionuclides in nature. Although it is probably best known for dating in archaeology, in the case of the general public, it represents a useful tracer to study our environment, both in the past and nowadays. For instance, carbonaceous particles, which are in many cases the most abundant among aerosols constituents, are believed to play a major role in both health and climatic effects of aerosols. In particular, measurement of radiocarbon concentration in particulate matter samples can give information on the contributions of the fossil fuels combustion and of natural sources to the carbonaceous fraction in aerosols. These measurements are especially effective when separately performed on different carbonaceous fractions, like elemental and organic carbon (EC and OC, respectively). Past climate is also studied thanks to old archives, as e.g. marine sediments can be. In this case, instead of radiocarbon dating the bulk sediment, a reliable method to fix chronological markers is represented by dating foraminifera tests of CaCO3 picked from different layers in the sediment. Both the aforementioned applications are characterized by the fact that the samples that can be collected for 14C measurements are typically very small, i.e. few mg or less (before any treatment). Accelerator Mass Spectrometry (AMS) is thus the only technique that can be applied to measure radiocarbon in such samples. Anyway, measurements cannot be so straightforward. In the case of the measurement of radiocarbon concentration in aerosol samples, a preparation line especially dedicated to the extraction of only the carbonaceous fraction of interest is mandatory. Actually, this line should include a combustion oven, from which either total carbon or EC and OC can separately evolve, and a system of traps to purify and collect the CO2. In the case of foraminifera tests (inorganic carbon), special care must be taken in the pre-treatment phase: foraminifera can

  11. Radiocarbon evidence for extensive plate-boundary rupture about 300 years ago at the Cascadia subduction zone

    USGS Publications Warehouse

    Nelson, A.R.; Atwater, B.F.; Bobrowsky, P.T.; Bradley, L.-A.; Clague, J.J.; Carver, G.A.; Darienzo, M.E.; Grant, W.C.; Krueger, H.W.; Sparks, R.; Stafford, Thomas W., Jr.; Stuiver, M.

    1995-01-01

    THE Cascadia subduction zone, a region of converging tectonic plates along the Pacific coast of North America, has a geological history of very large plate-boundary earthquakes1,2, but no such earthquakes have struck this region since Euro-American settlement about 150 years ago. Geophysical estimates of the moment magnitudes (Mw) of the largest such earthquakes range from 8 (ref. 3).to 91/2 (ref. 4). Radiocarbon dating of earthquake-killed vegetation can set upper bounds on earthquake size by constraining the length of plate boundary that ruptured in individual earthquakes. Such dating has shown that the most recent rupture, or series of ruptures, extended at least 55 km along the Washington coast within a period of a few decades about 300 years ago5. Here we report 85 new 14C ages, which suggest that this most recent rupture (or series) extended at least 900 km between southern British Columbia and northern California. By comparing the 14C ages with written records of the past 150 years, we conclude that a single magnitude 9 earthquake, or a series of lesser earthquakes, ruptured most of the length of the Cascadia subduction zone between the late 1600s and early 1800s, and probably in the early 1700s.

  12. Complexities in the Use of Bomb-Curve Radiocarbon to Determine Time Since Death of Human Skeletal Remains

    SciTech Connect

    Ubelaker, D H; Buchholz, B A

    2005-04-26

    Atmospheric testing of nuclear weapons during the 1950s and early 1960s doubled the level of radiocarbon ({sup 14}C) in the atmosphere. From the peak in 1963, the level of {sup 14}CO{sub 2} has decreased exponentially with a mean life of about 16 years, not due to radioactive decay, but due to mixing with large marine and terrestrial carbon reservoirs. Since radiocarbon is incorporated into all living things, the bomb-pulse is an isotopic chronometer of the past half century. The absence of bomb radiocarbon in skeletonized human remains generally indicates a date of death before 1950. Comparison of the radiocarbon values with the post 1950 bomb-curve may also help elucidate when in the post 1950 era, the individual was still alive. Such interpretation however, must consider the age at death of the individual and the type of tissue sampled.

  13. Radiocarbon Age Offsets in Arctic Lake Sediments Describe the Vulnerability of Permafrost Carbon to Past Climate Warming

    NASA Astrophysics Data System (ADS)

    Gaglioti, B.; Mann, D. H.; Pohlman, J.; Kunz, M. L.; Jones, B. M.; Jones, M.; Wooller, M. J.

    2012-12-01

    A warming climate in the future could release permafrost carbon (C) as carbon dioxide and methane to the atmosphere, causing a positive feedback to climate warming. An effective approach to better understanding this problem is to observe how permafrost C dynamics responded to past warming events. Here we use the sediment record of a lake basin in northern Alaska as a long-term archive for past permafrost C release from the surrounding watershed. The age of deposition and burial for an arctic lake sediment horizon is often younger than the 14C age because of old, 14C-depleted C eroded or leached from peat, soil, and thawing permafrost in the watershed. Changes in the magnitude between the age of deposition ("true age") and the radiocarbon age of the bulk sediment from the same layer is the radiocarbon age-offset, which serves as a gauge for the relative amount of permafrost C released from the watershed. We analyzed the sediments of Lake of the Pleistocene (LOP), a partially-drained lake basin located in the northern flank of the Brooks Range that contains continuously deposited sediments spanning the last 14,500 calendar years. The LOP watershed is underlain by continuous permafrost and contains extensive, frozen peatlands. We were able to excavate a wide swath of the former lakebed and collect hundreds of willow twigs and sediment samples to construct a high-resolution age-offset chronology. We dated well-preserved willow twigs that are directly blown into the lake to obtain a "true" 14C age and the age of bulk lake-sediment organic matter from the same layer that records the age of both primary productivity from within the lake and of the old dissolved and particulate organic carbon reworked from the watershed. Today, the radiocarbon age of the surface sediments of LOP is 2,000 calendar years old, which is roughly the same as the age offset during the Younger Dryas cold interval. During the warmer than present Holocene Thermal Maximum (HTM; ~11,700-9,000 calendar

  14. Radiocarbon measurements constrain the fossil and biological components of total CO2

    NASA Astrophysics Data System (ADS)

    Miller, J. B.; Lehman, S. J.; Tans, P. P.; Turnbull, J. C.

    2009-12-01

    In a rapidly evolving environment in which binding treaties and laws at the international, national and state levels are likely to limit greenhouse gas emissions, it will be critical for society to have independent verification of emissions and their accumulation in the atmosphere. Current treaties and laws like the Kyoto Protocol and California’s AB32 rely upon “bottom-up” reporting by governments and industry from inventories and process models to assess emissions. What we propose here is that to promote accuracy and transparency, it will also be necessary to verify these “bottom-up” approaches from the “top-down” perspective of the atmosphere. In particular, total CO2, which is the bottom line for climate forcing, and fossil fuel CO2, which is the primary driver of the observed increase need to be monitored. Total CO2 is already measured at high precision and accuracy at numerous sites nationally and globally by a variety of university and government entities (see e.g., www.esrl.noaa.gov/gmd/ccgg/globalview/). CO2 measurements in more locations and at higher frequencies are required to establish tighter constraints to emissions. For fossil fuel CO2, however, we require measurements of the rare isotopic species 14CO2. Fossil fuel emissions of CO2 are devoid of 14 (radiocarbon), because, by definition, these fuels are many millions of years old and the 14 half-life is only 5730 years. This makes 14CO2 an ideal tracer for fossil fuel emissions. Here we will present results of a nascent United States 14CO2 observation program that together with model simulations suggest a large number of 14CO2 measurements over the coterminous USA would allow for tight (~20%) regional (~105 - 106 km2) constraints on fossil fuel emissions at annual or seasonal time scales. Additionally, correlations of our 14CO2 observations with a wide suite of anthropogenic tracers suggest that “tuning” of these tracers with 14CO2 for fossil fuel detection may be possible

  15. The First Radiocarbon-Constrained Full-Vector Holocene Paleomagnetic Secular Variation Reconstruction for Eastern Canada

    NASA Astrophysics Data System (ADS)

    Barletta, F.; St-Onge, G.; Stoner, J.; Lajeunesse, P.

    2009-05-01

    Here we present the first high-resolution Holocene paleomagnetic secular variation (PSV) master curve and relative paleointensity stack constrained by radiocarbon dates for Eastern Canada. This reconstruction is based on seven sedimentary sequences collected from the St. Lawrence Estuary and Gulf from the head to the mouth of the Laurentian Channel. The natural remanent magnetization (NRM), the anhysteretic remanent magnetization (ARM) and the isothermal remanent magnetization (IRM) were measured on u-channel samples at the Paleomagnetism Laboratory of ISMER using a 2G Enterprises cryogenic magnetometer. Magnetic mineralogy was additionally assessed using a recently installed alternative gradient force magnetometer (AGM). The magnetic mineralogy of the Holocene postglacial sediments is mainly carried by low-coercivity ferrimagnetic minerals (most likely magnetite) in the pseudo-single domain size range. The characteristic remanent magnetization (ChRM), assessed by principal component analysis, reveals the presence of a stable and well-defined magnetization characterized by maximum angular deviation (MAD) values generally lower than 5°. Furthermore, ChRM inclinations fluctuate around the expected geocentric axial dipole (GAD) magnetic inclination for the latitude of the coring sites (from 63° to 66°). The similarity of these records on their own independent timescales implies that all of the individual sedimentary sequences record a reliable Holocene PSV record for Eastern Canada. Relative paleointensity (RPI) was estimated by normalizing the NRM by the ARM which provided the best coercivity match. Lastly, the paleomagnetic directional and RPI records were stacked on a common time scale spanning the last ~10 000 cal BP. The smoothed PSV stack reveal centennial- to millennial-scale geomagnetic features concordant with the CALS7K.2 time-varying spherical harmonic model, as well as with the US eastern stack (King and Peck, 2001). Comparisons further a field with the

  16. Pollen-based biome reconstructions for Latin America at 0, 6000 and 18 000 radiocarbon years

    USGS Publications Warehouse

    Marchant, R.; Harrison, S.P.; Hooghiemstra, H.; Markgraf, Vera; Van Boxel, J. H.; Ager, T.; Almeida, L.; Anderson, R.; Baied, C.; Behling, H.; Berrio, J.C.; Burbridge, R.; Bjorck, S.; Byrne, R.; Bush, M.B.; Cleef, A.M.; Duivenvoorden, J.F.; Flenley, J.R.; De Oliveira, P.; Van Geel, B.; Graf, K.J.; Gosling, W.D.; Harbele, S.; Van Der Hammen, T.; Hansen, B.C.S.; Horn, S.P.; Islebe, G.A.; Kuhry, P.; Ledru, M.-P.; Mayle, F.E.; Leyden, B.W.; Lozano-Garcia, S.; Melief, A.B.M.; Moreno, P.; Moar, N.T.; Prieto, A.; Van Reenen, G. B.; Salgado-Labouriau, M. L.; Schasignbitz, F.; Schreve-Brinkman, E. J.; Wille, M.

    2009-01-01

    The biomisation method is used to reconstruct Latin American vegetation at 6000±500 and 18 000±1000 radiocarbon years before present (14C yr BP) from pollen data. Tests using modern pollen data from 381 samples derived from 287 locations broadly reproduce potential natural vegetation. The strong temperature gradient associated with the Andes is recorded by a transition from high altitude cool grass/shrubland and cool mixed forest to mid-altitude cool temperate rain forest, to tropical dry, seasonal and rain forest at low altitudes. Reconstructed biomes from a number of sites do not match the potential vegetation due to local factors such as human impact, methodological artefacts and mechanisms of pollen representivity of the parent vegetation.

    At 6000±500 14C yr BP 255 samples are analysed from 127 sites. Differences between the modern and the 6000±500 14C yr BP reconstruction are comparatively small. Patterns of change relative to the modern reconstruction are mainly to biomes characteristic of drier climate in the north of the region with a slight more mesic shift in the south. Cool temperate rain forest remains dominant in western South America. In northwestern South America a number of sites record transitions from tropical seasonal forest to tropical dry forest and tropical rain forest to tropical seasonal forest. Sites in Central America also show a change in biome assignment to more mesic vegetation, indicative of greater plant available moisture, e.g. on the Yucat??n peninsula sites record warm evergreen forest, replacing tropical dry forest and warm mixed forest presently recorded.

    At 18 000±1000 14C yr BP 61 samples from 34 sites record vegetation that reflects a generally cool and dry environment. Cool grass/shrubland prevalent in southeast Brazil, Amazonian sites record tropical dry forest, warm temperate rain forest and tropical seasonal forest. Southernmost South America is dominated by cool grass/shrubland, a single site

  17. Pollen-based biome reconstructions for Latin America at 0, 6000 and 18 000 radiocarbon years

    USGS Publications Warehouse

    Marchant, R.; Harrison, S.P.; Hooghiemstra, H.; Markgraf, Vera; Van Boxel, J. H.; Ager, T.; Almeida, L.; Anderson, R.; Baied, C.; Behling, H.; Berrio, J.C.; Burbridge, R.; Bjorck, S.; Byrne, R.; Bush, M.B.; Cleef, A.M.; Duivenvoorden, J.F.; Flenley, J.R.; De Oliveira, P.; Van Geel, B.; Graf, K.J.; Gosling, W.D.; Harbele, S.; Van Der Hammen, T.; Hansen, B.C.S.; Horn, S.P.; Islebe, G.A.; Kuhry, P.; Ledru, M.

    2009-01-01

    The biomisation method is used to reconstruct Latin American vegetation at 6000±500 and 18 000±1000 radiocarbon years before present (14C yr BP) from pollen data. Tests using modern pollen data from 381 samples derived from 287 locations broadly reproduce potential natural vegetation. The strong temperature gradient associated with the Andes is recorded by a transition from high altitude cool grass/shrubland and cool mixed forest to mid-altitude cool temperate rain forest, to tropical dry, seasonal and rain forest at low altitudes. Reconstructed biomes from a number of sites do not match the potential vegetation due to local factors such as human impact, methodological artefacts and mechanisms of pollen representivity of the parent vegetation. At 6000±500 14C yr BP 255 samples are analysed from 127 sites. Differences between the modern and the 6000±500 14C yr BP reconstruction are comparatively small. Patterns of change relative to the modern reconstruction are mainly to biomes characteristic of drier climate in the north of the region with a slight more mesic shift in the south. Cool temperate rain forest remains dominant in western South America. In northwestern South America a number of sites record transitions from tropical seasonal forest to tropical dry forest and tropical rain forest to tropical seasonal forest. Sites in Central America also show a change in biome assignment to more mesic vegetation, indicative of greater plant available moisture, e.g. on the Yucat??n peninsula sites record warm evergreen forest, replacing tropical dry forest and warm mixed forest presently recorded. At 18 000±1000 14C yr BP 61 samples from 34 sites record vegetation that reflects a generally cool and dry environment. Cool grass/shrubland prevalent in southeast Brazil, Amazonian sites record tropical dry forest, warm temperate rain forest and tropical seasonal forest. Southernmost South America is dominated by cool grass/shrubland, a single site retains cool temperate

  18. Radiocarbon dates from the Grotte du Renne and Saint-Césaire support a Neandertal origin for the Châtelperronian

    PubMed Central

    Hublin, Jean-Jacques; Talamo, Sahra; Julien, Michèle; David, Francine; Connet, Nelly; Bodu, Pierre; Vandermeersch, Bernard; Richards, Michael P.

    2012-01-01

    The transition from the Middle Paleolithic (MP) to Upper Paleolithic (UP) is marked by the replacement of late Neandertals by modern humans in Europe between 50,000 and 40,000 y ago. Châtelperronian (CP) artifact assemblages found in central France and northern Spain date to this time period. So far, it is the only such assemblage type that has yielded Neandertal remains directly associated with UP style artifacts. CP assemblages also include body ornaments, otherwise virtually unknown in the Neandertal world. However, it has been argued that instead of the CP being manufactured by Neandertals, site formation processes and layer admixture resulted in the chance association of Neanderthal remains, CP assemblages, and body ornaments. Here, we report a series of accelerator mass spectrometry radiocarbon dates on ultrafiltered bone collagen extracted from 40 well-preserved bone fragments from the late Mousterian, CP, and Protoaurignacian layers at the Grotte du Renne site (at Arcy-sur-Cure, France). Our radiocarbon results are inconsistent with the admixture hypothesis. Further, we report a direct date on the Neandertal CP skeleton from Saint-Césaire (France). This date corroborates the assignment of CP assemblages to the latest Neandertals of western Europe. Importantly, our results establish that the production of body ornaments in the CP postdates the arrival of modern humans in neighboring regions of Europe. This new behavior could therefore have been the result of cultural diffusion from modern to Neandertal groups. PMID:23112183

  19. A Radiocarbon Chronology of Hunter-Gatherer Occupation from Bodega Bay, California, USA

    SciTech Connect

    Kennedy, M A; Russell, A D; Guilderson, T P

    2005-04-27

    The evolution of hunter-gatherer maritime adaptations in western North America has been a prominent topic of discussion among archaeologists in recent years (e.g. Arnold 1992; Erlandson and Colten 1991; Erlandson and Glassow 1997; Lightfoot 1993). Although vast coastal regions of the northeastern Pacific (for example, southern California) have been investigated in detail, our understanding of hunter-gatherer developments along the coast of northern California is limited. Previous research indicates that humans have exploited marine mammals, fish and shellfish along the northern California shoreline since the early Holocene (Schwaderer 1992). By the end of the late Holocene, some groups remained year-round on the coast subsisting primarily on marine resources (e.g. Gould 1975; Hildebrandt and Levulett 2002). However, a paucity of well-dated cultural deposits has hindered our understanding of these developments, particularly during the early and middle Holocene. The lack of a long and reliable chronological sequence has restricted our interpretations of behavioral change, including the adaptive strategies (such as foraging, mobility and settlement) used by human foragers to colonize and inhabit the coastal areas of this region. These shortcomings have also hindered comparative interpretations with other coastal and inland regions in western North America. Here we present a Holocene radiocarbon chronology of hunter-gatherer occupation based on contemporaneous samples of charcoal and Mytilus californianus (California sea mussel) shell recovered from seven archaeological sites near Bodega Bay, California. A series of 127 {sup 14}C ages reveal a chronological sequence that spans from ca. 8940-110 cal BP (1{sigma}) (7890-160 {sup 14}C yr BP = charcoal; 8934-101 {sup 14}C yr BP = shell). As part of this sequence, we report new {sup 14}C dates from the stratified cave and open-air midden deposits at Duncan's Landing (CA-SON-348/H). In addition, we present {sup 14}C ages

  20. Accelerator-mass spectrometer (AMS) radiocarbon dating of Pleistocene lake sediments in the Great Basin

    USGS Publications Warehouse

    Thompson, R.S.; Toolin, L.J.; Forester, R.M.; Spencer, R.J.

    1990-01-01

    Pleistocene lake sediments in the Great Basin typically contain little organic carbon, and thus are difficult to date reliably by conventional radioccarbon methods. Paleoenvironmental data are abundant in these sediments, but are of limited value without adequate age controls. With the advent of accelerator-mass spectrometer (AMS) radiocarbon dating, it is now possible to date these paleolacustrine sediments. AMS dates were obtained on sediment cores from the Bonneville, Franklin, and Lahontan Basins. In the Bonneville Basin, the AMS-based chronology compares well with other chronologies constructed from dated shore-zone features. In the Bonneville and Franklin basins, AMS dates delimit unconformities not apparent by other means. We found that dispersed organic carbon from sediments deposited during relatively freshwater intervals provided apparently reliable AMS radiocarbon dates. Carbonate microfossils from the Lahontan Basin also produced results that appear reasonable, while bulk carbonate yielded erroneous results. ?? 1990.

  1. Enhancing sample preparation capabilities for accelerator mass spectrometry radiocarbon and radiocalcium studies

    SciTech Connect

    Taylor, R.E.

    1991-08-20

    With support provided by the LLNL Accelerator Mass Spectrometry Laboratory, the UCR Radiocarbon Laboratory continued its studies involving sample pretreatment and target preparation for both AMS radiocarbon ({sup 14}C) and radiocalcium ({sup 41}Ca) involving applications to archaeologically -- and paleoanthropologically- related samples. With regard to AMS {sup 14}C-related studies, we have extended the development of a series of procedures which have, as their initial goal, the capability to combust several hundred microgram amounts of a chemically-pretreated organic sample and convert the resultant CO{sub 2} to graphitic carbon which will consistently yield relatively high {sup 13}C{sup {minus}} ion currents and blanks which will yield, on a consistent basis, {sup 14}C count rates at or below 0.20% modern, giving an 2 sigma age limit of >50,000 yr BP.

  2. Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus).

    PubMed

    Nielsen, Julius; Hedeholm, Rasmus B; Heinemeier, Jan; Bushnell, Peter G; Christiansen, Jørgen S; Olsen, Jesper; Ramsey, Christopher Bronk; Brill, Richard W; Simon, Malene; Steffensen, Kirstine F; Steffensen, John F

    2016-08-12

    The Greenland shark (Somniosus microcephalus), an iconic species of the Arctic Seas, grows slowly and reaches >500 centimeters (cm) in total length, suggesting a life span well beyond those of other vertebrates. Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm in total length) revealed a life span of at least 272 years. Only the smallest sharks (220 cm or less) showed signs of the radiocarbon bomb pulse, a time marker of the early 1960s. The age ranges of prebomb sharks (reported as midpoint and extent of the 95.4% probability range) revealed the age at sexual maturity to be at least 156 ± 22 years, and the largest animal (502 cm) to be 392 ± 120 years old. Our results show that the Greenland shark is the longest-lived vertebrate known, and they raise concerns about species conservation. PMID:27516602

  3. Adaptive Neuromorphic Circuit for Stereoscopic Disparity Using Ocular Dominance Map.

    PubMed

    Sharma, Sheena; Gupta, Priti; Markan, C M

    2016-01-01

    Stereopsis or depth perception is a critical aspect of information processing in the brain and is computed from the positional shift or disparity between the images seen by the two eyes. Various algorithms and their hardware implementation that compute disparity in real time have been proposed; however, most of them compute disparity through complex mathematical calculations that are difficult to realize in hardware and are biologically unrealistic. The brain presumably uses simpler methods to extract depth information from the environment and hence newer methodologies that could perform stereopsis with brain like elegance need to be explored. This paper proposes an innovative aVLSI design that leverages the columnar organization of ocular dominance in the brain and uses time-staggered Winner Take All (ts-WTA) to adaptively create disparity tuned cells. Physiological findings support the presence of disparity cells in the visual cortex and show that these cells surface as a result of binocular stimulation received after birth. Therefore, creating in hardware cells that can learn different disparities with experience not only is novel but also is biologically more realistic. These disparity cells, when allowed to interact diffusively on a larger scale, can be used to adaptively create stable topological disparity maps in silicon. PMID:27243029

  4. Asthma Management Disparities: A Photovoice Investigation with African American Youth

    ERIC Educational Resources Information Center

    Evans-Agnew, Robin

    2016-01-01

    Disparities in asthma management are a burden on African American youth. The objective of this study is to describe and compare the discourses of asthma management disparities (AMDs) in African American adolescents in Seattle to existing youth-related asthma policies in Washington State. Adolescents participated in a three-session photovoice…

  5. Adaptive Neuromorphic Circuit for Stereoscopic Disparity Using Ocular Dominance Map

    PubMed Central

    Sharma, Sheena; Gupta, Priti; Markan, C. M.

    2016-01-01

    Stereopsis or depth perception is a critical aspect of information processing in the brain and is computed from the positional shift or disparity between the images seen by the two eyes. Various algorithms and their hardware implementation that compute disparity in real time have been proposed; however, most of them compute disparity through complex mathematical calculations that are difficult to realize in hardware and are biologically unrealistic. The brain presumably uses simpler methods to extract depth information from the environment and hence newer methodologies that could perform stereopsis with brain like elegance need to be explored. This paper proposes an innovative aVLSI design that leverages the columnar organization of ocular dominance in the brain and uses time-staggered Winner Take All (ts-WTA) to adaptively create disparity tuned cells. Physiological findings support the presence of disparity cells in the visual cortex and show that these cells surface as a result of binocular stimulation received after birth. Therefore, creating in hardware cells that can learn different disparities with experience not only is novel but also is biologically more realistic. These disparity cells, when allowed to interact diffusively on a larger scale, can be used to adaptively create stable topological disparity maps in silicon. PMID:27243029

  6. Racial/Ethnic Disparities in ADHD Diagnosis by Kindergarten Entry

    ERIC Educational Resources Information Center

    Morgan, Paul L.; Hillemeier, Marianne M.; Farkas, George; Maczuga, Steve

    2014-01-01

    Background: Whether and to what extent racial/ethnic disparities in attention-deficit/hyperactivity disorder (ADHD) diagnosis occur by kindergarten entry is currently unknown. We investigated risk factors associated with an ADHD diagnosis by kindergarten entry generally, and specifically whether racial/ethnic disparities in ADHD diagnosis occur by…

  7. Biomarkers of psychological stress in health disparities research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Health disparities in the United States have been documented in population groups defined by SES, ethnicity and/or race. The etiology of these health disparities is multifacted and complex. While some factors, such as access to care, may have obvious effects on health, the contribution of psycholo...

  8. Male/Female Salary Disparity for Professors of Educational Administration.

    ERIC Educational Resources Information Center

    Pounder, Diana G.

    The earnings gap between male and female workers across all occupational groups has been well documented; full-time women workers earn, on average, approximately 65 percent of men's salaries. Although male/female salary disparity is largest across occupational groups, salary disparity within occupational groups still prevails. For example, the…

  9. Reducing Health Disparities: The Perfect Fit for Counseling Psychology

    ERIC Educational Resources Information Center

    Buki, Lydia P.

    2007-01-01

    This reaction to the Major Contribution presents a conceptualization of health disparities as another form of oppression of marginalized populations in our society. Consistent with this view, health disparities are then situated within a larger, national context, showing that counseling psychologists' involvement is an integral part of a…

  10. Stigma and Racial/Ethnic HIV Disparities: Moving Toward Resilience

    PubMed Central

    Earnshaw, Valerie A.; Bogart, Laura M.; Dovidio, John F.; Williams, Davird R.

    2013-01-01

    Prior research suggests that stigma plays a role in racial/ethnic health disparities. However, there is limited understanding about the mechanisms by which stigma contributes to HIV-related disparities in risk, incidence and screening, treatment, and survival and what can be done to reduce the impact of stigma on these disparities. We introduce the Stigma and HIV Disparities Model to describe how societal stigma related to race and ethnicity is associated with racial/ethnic HIV disparities via its manifestations at the structural level (e.g., residential segregation) as well as the individual level among perceivers (e.g., discrimination) and targets (e.g., internalized stigma). We then review evidence of these associations. Because racial/ethnic minorities at risk of and living with HIV often possess multiple stigmas (e.g., HIV-positive, substance use), we adopt an intersectionality framework and conceptualize interdependence among co-occurring stigmas. We further propose a resilience agenda and suggest that intervening on modifiable strength-based moderators of the association between societal stigma and disparities can reduce disparities. Strengthening economic and community empowerment and trust at the structural level, creating common ingroup identities and promoting contact with people living with HIV among perceivers at the individual level, and enhancing social support and adaptive coping among targets at the individual level can improve resilience to societal stigma and ultimately reduce racial/ethnic HIV disparities. PMID:23688090

  11. Gender Disparities in Science and Engineering in Chinese Universities

    ERIC Educational Resources Information Center

    Guo, Congbin; Tsang, Mun C.; Ding, Xiaohao

    2010-01-01

    Gender disparities in science and engineering majors in Chinese universities have received increasing attention from researchers and educators in China in recent years. Using data from a national survey of college students who graduated in 2005, this study documents gender disparities in enrollment and academic performance in science and…

  12. Luminance, Colour, Viewpoint and Border Enhanced Disparity Energy Model

    PubMed Central

    Martins, Jaime A.; Rodrigues, João M. F.; du Buf, Hans

    2015-01-01

    The visual cortex is able to extract disparity information through the use of binocular cells. This process is reflected by the Disparity Energy Model, which describes the role and functioning of simple and complex binocular neuron populations, and how they are able to extract disparity. This model uses explicit cell parameters to mathematically determine preferred cell disparities, like spatial frequencies, orientations, binocular phases and receptive field positions. However, the brain cannot access such explicit cell parameters; it must rely on cell responses. In this article, we implemented a trained binocular neuronal population, which encodes disparity information implicitly. This allows the population to learn how to decode disparities, in a similar way to how our visual system could have developed this ability during evolution. At the same time, responses of monocular simple and complex cells can also encode line and edge information, which is useful for refining disparities at object borders. The brain should then be able, starting from a low-level disparity draft, to integrate all information, including colour and viewpoint perspective, in order to propagate better estimates to higher cortical areas. PMID:26107954

  13. Black-white preterm birth disparity: a marker of inequality

    EPA Science Inventory

    Purpose. The racial disparity in preterrn birth (PTB) is a persistent feature of perinatal epidemiology, inconsistently modeled in the literature. Rather than include race as an explanatory variable, or employ race-stratified models, we sought to directly model the PTB disparity ...

  14. Vector Disparity Sensor with Vergence Control for Active Vision Systems

    PubMed Central

    Barranco, Francisco; Diaz, Javier; Gibaldi, Agostino; Sabatini, Silvio P.; Ros, Eduardo

    2012-01-01

    This paper presents an architecture for computing vector disparity for active vision systems as used on robotics applications. The control of the vergence angle of a binocular system allows us to efficiently explore dynamic environments, but requires a generalization of the disparity computation with respect to a static camera setup, where the disparity is strictly 1-D after the image rectification. The interaction between vision and motor control allows us to develop an active sensor that achieves high accuracy of the disparity computation around the fixation point, and fast reaction time for the vergence control. In this contribution, we address the development of a real-time architecture for vector disparity computation using an FPGA device. We implement the disparity unit and the control module for vergence, version, and tilt to determine the fixation point. In addition, two on-chip different alternatives for the vector disparity engines are discussed based on the luminance (gradient-based) and phase information of the binocular images. The multiscale versions of these engines are able to estimate the vector disparity up to 32 fps on VGA resolution images with very good accuracy as shown using benchmark sequences with known ground-truth. The performances in terms of frame-rate, resource utilization, and accuracy of the presented approaches are discussed. On the basis of these results, our study indicates that the gradient-based approach leads to the best trade-off choice for the integration with the active vision system. PMID:22438737

  15. Towards constraining the stratosphere-troposphere exchange of radiocarbon: strategies of stratospheric 14CO2 measurements using AirCore

    NASA Astrophysics Data System (ADS)

    Chen, Huilin; Paul, Dipayan; Meijer, Harro; Miller, John; Kivi, Rigel; Krol, Maarten

    2016-04-01

    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 stratosphere due to the cosmogenic production. To this end, better understanding the stratospheric radiocarbon source is very useful to advance the use of radiocarbon for these applications. However, stratospheric 14C observations have been very limited so that there are large uncertainties on 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 14C measurements using AirCore samples from Sodankylä, Northern Finland. AirCore is an innovative atmospheric sampling system, which passively collects atmospheric air samples into a long piece of coiled stainless steel tubing during the descent of a balloon flight. Due to the relatively low cost of the consumables, there is a potential to make such AirCore profiling in other parts of the world on a regular basis. In this study, we simulate the 14C in the atmosphere and assess the stratosphere-troposphere exchange of radiocarbon using the TM5 model. The Sodankylä radiocarbon measurements will be used to verify the performance of the model at high latitude. Besides this, we will also 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, and based on the results design a strategy to set up a 14C measurement program using AirCore.

  16. 3D visual discomfort predictor: analysis of horizontal disparity and neural activity statistics.

    PubMed

    Park, Jincheol; Oh, Heeseok; Lee, Sanghoon; Bovik, Alan Conrad

    2015-03-01

    Being able to predict the degree of visual discomfort that is felt when viewing stereoscopic 3D (S3D) images is an important goal toward ameliorating causative factors, such as excessive horizontal disparity, misalignments or mismatches between the left and right views of stereo pairs, or conflicts between different depth cues. Ideally, such a model should account for such factors as capture and viewing geometries, the distribution of disparities, and the responses of visual neurons. When viewing modern 3D displays, visual discomfort is caused primarily by changes in binocular vergence while accommodation in held fixed at the viewing distance to a flat 3D screen. This results in unnatural mismatches between ocular fixations and ocular focus that does not occur in normal direct 3D viewing. This accommodation vergence conflict can cause adverse effects, such as headaches, fatigue, eye strain, and reduced visual ability. Binocular vision is ultimately realized by means of neural mechanisms that subserve the sensorimotor control of eye movements. Realizing that the neuronal responses are directly implicated in both the control and experience of 3D perception, we have developed a model-based neuronal and statistical framework called the 3D visual discomfort predictor (3D-VDP)that automatically predicts the level of visual discomfort that is experienced when viewing S3D images. 3D-VDP extracts two types of features: 1) coarse features derived from the statistics of binocular disparities and 2) fine features derived by estimating the neural activity associated with the processing of horizontal disparities. In particular, we deploy a model of horizontal disparity processing in the extrastriate middle temporal region of occipital lobe. We compare the performance of 3D-VDP with other recent discomfort prediction algorithms with respect to correlation against recorded subjective visual discomfort scores,and show that 3D-VDP is statistically superior to the other methods. PMID

  17. Radiocarbon variability in modern deep-sea bamboo coral skeletons from the North Atlantic

    NASA Astrophysics Data System (ADS)

    Farmer, J. R.; Hoenisch, B.; Robinson, L. F.

    2013-12-01

    Geochemical records from modern and recent deep-sea corals can provide new opportunities for understanding how changes in intermediate to deep ocean chemistry and circulation relate to climatic changes during the Common Era. Of critical importance for such comparisons are well-constrained coral growth rates (and hence chronology). Bamboo coral specimens of the genus Keratoisis are widely distributed in the modern oceans, but their calcitic skeletons exhibit open system U-Th behavior and many specimens show obscure growth banding, limiting available techniques for growth rate determinations. We measured radial transects of radiocarbon across the skeletons of six Keratoisis specimens that were live-collected in the northwestern North Atlantic Ocean between 1879 and 2005. Initial results show that Δ14C from the outer surface of three modern corals is within error of seawater Δ14C estimates at the site of coral collection from GLODAP. Most specimens show increasing 14C age toward the coral center, implying near-linear growth rates of 40 to 60 μm/14C year that are consistent with growth rates for North Atlantic Keratoisis specimens established by skeletal 210Pb and organic (gorgonian) 14C measurements. However, other specimens show radiocarbon variability that precludes accurate growth rate determinations for parts of the skeleton. In particular, multiple specimens exhibit systematic radiocarbon age reversals within 1-3 mm of the central growth axis, which is assumed to be the ontogenetically oldest part of the skeleton. This observation is consistent with previously published records of elevated unsupported 210Pb around the central growth axis of some North Atlantic Keratoisis specimens. We discuss potential physical and biological causes for the observed radiocarbon variability and implications for accurate growth rate determinations for bamboo coral skeletons.

  18. Radiocarbon calibration-comparison records based on marine sediments from the Pakistan and Iberian Margins

    NASA Astrophysics Data System (ADS)

    Bard, E.; Ménot, G.; Licari, L.

    2009-04-01

    We present new results on the radiocarbon records based on planktonic foraminifera of core MD042876 from the Pakistan Margin and updated results for core MD952042 from the Iberian Margin (Bard et al. 2004, Science 303, 178; 2004, Quat. Res. 61, 204; 2004, Radiocarbon 46, 1189; Shackleton et al. 2004, QSR 23, 1513). Both cores exhibit high sedimentation rates on the order of 50 and 40 cm/kyr for the Pakistan and Iberian cores, respectively. For a calendar age scale, we matched climate records of both cores to the oxygen isotopic profile of the Hulu Cave stalagmites that have been accurately dated by U-Th (Wang et al. 2001, Science 294, 2345). Our new comparison data can be compared with the IntCal04 record (Reimer et al. 2004, Radiocarbon 46, 1029) and with individual records based on other archives: corals from Barbados (Fairbanks et al. 2005, QSR 24, 1781), marine sediments of the Cariaco Basin (Hughen et al. 2004, Science 303, 202; 2006, QSR 25, 3216), varves of Lake Suigetsu (Kitagawa & van der Plicht 1998, Science 279, 1187; 2000, Radiocarbon 42, 369), and speleothems from the Bahamas (Beck et al. 2001, Science 292, 2453). Up to 26,000 cal-yr-BP, the Pakistan and Iberian data can be used to validate the precision and accuracy of the marine sediment approach. In the interval between 26,000 and 50,000 cal-yr-B.P., the Pakistan and Iberian records agree closely with each other and with the Cariaco and Barbados data. This agreement clearly shows the feasibility of extending the IntCal04 14C calibration curve.

  19. A Rapid Radiocarbon Method for Age Surveys of Southern Ocean Deep-sea Corals

    NASA Astrophysics Data System (ADS)

    Burke, A.; Robinson, L. F.; Gerlach, D. S.; Jenkins, W. J.; McNichol, A. P.

    2008-12-01

    Deep-sea corals provide a unique archive of past ocean radiocarbon because they are sessile and can be dated independently using U-series nuclides. One difficulty, however, is that using current techniques it is impractical to date large numbers of corals in order to determine which specimens have the appropriate ages for radiocarbon reconstructions. Here we present results from a quick method of making graphite for radiocarbon dating that reduces the amount of sample preparation time, thus allowing us to date a greater number of corals. In addition, these rapid age surveys provide important information on coral age populations, allowing us to examine coral distributions through time. The corals used in this study come from a sample set of about 6,000 specimens of Flabellum, Balanophyllia and Desmophyllum spp. collected from the Drake Passage area (50S -70S, 120 m-1700 m depth). Replicate samples from a single coral yielded a standard deviation of 81 years (n=9). Variations in sample mass (3 to 85 mg) have no clear effect on the Fm and furthermore, a simple cleaning using methanol yields the same results as a more involved cleaning procedure that includes an oxidizing solution and perchloric acid rinse. To improve the efficiency of the method, we assumed a delta13C = 0 per mil. This assumption is likely our largest source of uncertainty, resulting in offsets of up to 200 radiocarbon years over a reasonable range of delta13C. This level of uncertainty is sufficiently low to allow distinction between corals from different time periods over the past 35 ky (e.g. Last Glacial Maximum, Younger Dryas, etc.). To date, we have found corals from Burdwood Bank dating from the modern to the Younger Dryas and corals from the Drake Passage dating from the modern to Heinrich Event 1, which will be used in future paleo-climatic reconstructions in this important part of the ocean.

  20. Collagen Fingerprinting: A New Screening Technique for Radiocarbon Dating Ancient Bone.

    PubMed

    Harvey, Virginia L; Egerton, Victoria M; Chamberlain, Andrew T; Manning, Phillip L; Buckley, Michael

    2016-01-01

    Collagen is the dominant organic component of bone and is intimately locked within the hydroxyapatite structure of this ubiquitous biomaterial that dominates archaeological and palaeontological assemblages. Radiocarbon analysis of extracted collagen is one of the most common approaches to dating bone from late Pleistocene or Holocene deposits, but dating is relatively expensive compared to other biochemical techniques. Numerous analytical methods have previously been investigated for the purpose of screening out samples that are unlikely to yield reliable dates including histological analysis, UV-stimulated fluorescence and, most commonly, the measurement of percentage nitrogen (%N) and ratio of carbon to nitrogen (C:N). Here we propose the use of collagen fingerprinting (also known as Zooarchaeology by Mass Spectrometry, or ZooMS, when applied to species identification) as an alternative screening method for radiocarbon dating, due to its ability to provide information on collagen presence and quality, alongside species identification. The method was tested on a series of sub-fossil bone specimens from cave systems on Cayman Brac (Cayman Islands), chosen due to the observable range in diagenetic alteration, and in particular, the extent of mineralisation. Six (14)C dates, of 18 initial attempts, were obtained from remains of extinct hutia, Capromys sp. (Rodentia; Capromyidae), recovered from five distinct caves on Cayman Brac, and ranging from 393 ± 25 to 1588 ± 26 radiocarbon years before present (yr BP). All of the bone samples that yielded radiocarbon dates generated excellent collagen fingerprints, and conversely those that gave poor fingerprints also failed dating. Additionally, two successfully fingerprinted bone samples were screened out from a set of 81. Both subsequently generated (14)C dates, demonstrating successful utilisation of ZooMS as an alternative screening mechanism to identify bone samples that are suitable for 1(4)C analysis. PMID:26938469

  1. The radiocarbon age of calcite dissolving at the sea floor: Estimates from pore water data

    SciTech Connect

    Martin, W.R.; McNichol, A.P.; McCorkle, D.C.

    2000-04-01

    The authors measured the radiocarbon content and stable isotopic composition of pore water and bottom water {Sigma}CO{sub 2}, sedimentary organic carbon, and CaCO{sub 3} at two sites on the Ceara Rise, one underlying bottom water that is supersaturated with respect to calcite (Site B), the other underlying under saturated bottom water (Site G). The results were combined with pore water O{sub 2}, {Sigma}CO{sub 2}, and Ca{sup 2+} profiles (Martin and Sayles, 1996) to estimate the radiocarbon content of the CaCO{sub 3} that is dissolving in the sediment mixed layer. At Site G, the CaCO{sub 3} that is dissolving in the upper 2 cm of the sediments is clearly younger (richer in {sup 14}C) than the bulk sedimentary CaCO{sub 3}, indicating that nonhomogeneous CaCO{sub 3} dissolution occurs there. The case for nonhomogeneous dissolution is much weaker at the site underlying supersaturated bottom water. The results indicate that nonhomogeneous dissolution occurs in sediments underlying under saturated bottom water, that the dissolution is rapid relative to the rate of homogenization of the CaCO{sub 3} in the mixed layer by bioturbation, and that the dissolution rate of CaCO{sub 3} decreases as it ages in the sediment mixed layer. The results support the hypothesis, based on solid phase analyses, that the preferential dissolution of young (i.e., radiocarbon-rich) CaCO{sub 3} leads to a pattern of increasing radiocarbon age of mixed-layer CaCO{sub 3} as the degree of under saturation of bottom water increases (Keir, 1984; Broecker et al., 1991).

  2. Collagen Fingerprinting: A New Screening Technique for Radiocarbon Dating Ancient Bone

    PubMed Central

    Harvey, Virginia L.; Egerton, Victoria M.; Chamberlain, Andrew T.; Manning, Phillip L.; Buckley, Michael

    2016-01-01

    Collagen is the dominant organic component of bone and is intimately locked within the hydroxyapatite structure of this ubiquitous biomaterial that dominates archaeological and palaeontological assemblages. Radiocarbon analysis of extracted collagen is one of the most common approaches to dating bone from late Pleistocene or Holocene deposits, but dating is relatively expensive compared to other biochemical techniques. Numerous analytical methods have previously been investigated for the purpose of screening out samples that are unlikely to yield reliable dates including histological analysis, UV-stimulated fluorescence and, most commonly, the measurement of percentage nitrogen (%N) and ratio of carbon to nitrogen (C:N). Here we propose the use of collagen fingerprinting (also known as Zooarchaeology by Mass Spectrometry, or ZooMS, when applied to species identification) as an alternative screening method for radiocarbon dating, due to its ability to provide information on collagen presence and quality, alongside species identification. The method was tested on a series of sub-fossil bone specimens from cave systems on Cayman Brac (Cayman Islands), chosen due to the observable range in diagenetic alteration, and in particular, the extent of mineralisation. Six 14C dates, of 18 initial attempts, were obtained from remains of extinct hutia, Capromys sp. (Rodentia; Capromyidae), recovered from five distinct caves on Cayman Brac, and ranging from 393 ± 25 to 1588 ± 26 radiocarbon years before present (yr BP). All of the bone samples that yielded radiocarbon dates generated excellent collagen fingerprints, and conversely those that gave poor fingerprints also failed dating. Additionally, two successfully fingerprinted bone samples were screened out from a set of 81. Both subsequently generated 14C dates, demonstrating successful utilisation of ZooMS as an alternative screening mechanism to identify bone samples that are suitable for 14C analysis. PMID:26938469

  3. Health disparities among health care workers.

    PubMed

    Mawn, Barbara; Siqueira, Eduardo; Koren, Ainat; Slatin, Craig; Devereaux Melillo, Karen; Pearce, Carole; Hoff, Lee Ann

    2010-01-01

    In this article we describe the process of an interdisciplinary case study that examined the social contexts of occupational and general health disparities among health care workers in two sets of New England hospitals and nursing homes. A political economy of the work environment framework guided the study, which incorporated dimensions related to market dynamics, technology, and political and economic power. The purpose of this article is to relate the challenges encountered in occupational health care settings and how these could have impacted the study results. An innovative data collection matrix that guided small-group analysis provided a firm foundation from which to make design modifications to address these challenges. Implications for policy and research include the use of a political and economic framework from which to frame future studies, and the need to maintain rigor while allowing flexibility in design to adapt to challenges in the field. PMID:19940090

  4. Control strategy for cooperating disparate manipulators

    NASA Technical Reports Server (NTRS)

    Lew, Jae Young

    1989-01-01

    To manipulate large payloads typical of space construction, the concept of a small arm mounted on the end of a large arm is introduced. The main purposes of such a configuration are to increase the structural stiffness of the robot by bracing against or locking to a stationary frame, and to maintain a firm position constraint between the robot's base and workpieces by grasping them. Possible topologies for a combination of disparate large and small arms are discussed, and kinematics, dynamics, controls, and coordination of the two arms, especially when they brace at the tip of the small arm, are developed. The feasibility and improvement in performance are verified, not only with analytical work and simulation results but also with experiments on the existing arrangement Robotic Arm Large and Flexible and Small Articulated Manipulator.

  5. Racial disparities in survival among injured drivers.

    PubMed

    Haskins, Amy E; Clark, David E; Travis, Lori L

    2013-03-01

    Prior studies on racial and ethnic disparities in survival after motor vehicle crashes have examined only population-based death rates or have been restricted to hospitalized patients. In the current study, we examined 3 components of crash survival by race/ethnicity: survival overall, survival to reach a hospital, and survival among those hospitalized. Nine years of data (from 2000 through 2008) from the National Automotive Sampling System Crashworthiness Data System were used to examine white non-Hispanic, black non-Hispanic, and Hispanic drivers aged ≥ 15 years with serious injuries (injury severity scores of ≥ 9). By using multivariable logistic regression, we found that a driver's race/ethnicity was not significantly associated with overall survival after being injured in a crash (for blacks, odds ratio (OR) = 0.69, 95% confidence interval (CI): 0.36, 1.32; for Hispanics, OR = 1.00, 95% CI: 0.59, 1.72), and blacks and Hispanics were equally likely to survive to be treated at a hospital compared with whites (for blacks, OR = 1.00, 95% CI: 0.52, 1.93; for Hispanics, OR = 1.13, 95% CI: 0.71, 1.79). However, among patients who were treated at a hospital, blacks were 50% less likely to survive 30 days compared with whites (OR = 0.50, 95% CI: 0.33, 0.76). The disparity in survival after serious traffic injuries among blacks appears to occur after hospitalization, not in prehospital survival. PMID:23371352

  6. Racial Disparities in Survival Among Injured Drivers

    PubMed Central

    Haskins, Amy E.; Clark, David E.; Travis, Lori L.

    2013-01-01

    Prior studies on racial and ethnic disparities in survival after motor vehicle crashes have examined only population-based death rates or have been restricted to hospitalized patients. In the current study, we examined 3 components of crash survival by race/ethnicity: survival overall, survival to reach a hospital, and survival among those hospitalized. Nine years of data (from 2000 through 2008) from the National Automotive Sampling System Crashworthiness Data System were used to examine white non-Hispanic, black non-Hispanic, and Hispanic drivers aged ≥15 years with serious injuries (injury severity scores of ≥9). By using multivariable logistic regression, we found that a driver's race/ethnicity was not significantly associated with overall survival after being injured in a crash (for blacks, odds ratio (OR) = 0.69, 95% confidence interval (CI): 0.36, 1.32; for Hispanics, OR = 1.00, 95% CI: 0.59, 1.72), and blacks and Hispanics were equally likely to survive to be treated at a hospital compared with whites (for blacks, OR = 1.00, 95% CI: 0.52, 1.93; for Hispanics, OR = 1.13, 95% CI: 0.71, 1.79). However, among patients who were treated at a hospital, blacks were 50% less likely to survive 30 days compared with whites (OR = 0.50, 95% CI: 0.33, 0.76). The disparity in survival after serious traffic injuries among blacks appears to occur after hospitalization, not in prehospital survival. PMID:23371352

  7. Left behind: cancer disparities in the developed world.

    PubMed

    Dixit, Niharika; Crawford, Gregory B; Lemonde, Manon; Rittenberg, Cynthia N; Fernández-Ortega, Paz

    2016-08-01

    Huge advances have been made in cancer treatments over recent decades; however, significant disparities still exist in the developed world on the basis of race, socioeconomic status, education level, geographical location, and immigration status and in the United States, insurance status. Cancer disparities persist in the continuum of cancer care from risk factors, screening, diagnosis, treatment, survivorship, and end-of-life care. The causes of disparities are complex and multifactorial. The MASCC (Multinational Association of Supportive Care in Cancer) Education Study Group would like to propose a framework of cancer disparities from a social perspective utilizing "social determinants of health" as delineated by the World Health Organization and highlight an unmet need for research and policy innovations to address cancer disparities in developed world. PMID:27052305

  8. Vertical disparity and binocular vision in the praying mantis.

    PubMed

    Rossel, S; Mathis, U; Collett, T

    1992-02-01

    We have investigated how the binocular control of prey capture in the praying mantis is affected by abnormally large vertical disparities, which were introduced by prisms placed in front of the eyes. The position of a target on the two retinae determines both the magnitude of head saccades made to fixate a target and its perceived distance. Over the whole range of vertical disparities tested (up to at least 30 deg), the frequency of fixating saccades is normal while the amplitude of their vertical component is a compromise between the saccades specified by each eye individually. Distance measurements are not affected by imposed vertical disparities. But the larger the vertical disparity, the more reluctant the mantid is to strike at the target until disparities exceed 15 deg when no strikes are elicited at all. PMID:1558828

  9. Racial and Ethnic Disparities in the Quality of Health Care.

    PubMed

    Fiscella, Kevin; Sanders, Mechelle R

    2016-01-01

    The annual National Healthcare Quality and Disparities Reports document widespread and persistent racial and ethnic disparities. These disparities result from complex interactions between patient factors related to social disadvantage, clinicians, and organizational and health care system factors. Separate and unequal systems of health care between states, between health care systems, and between clinicians constrain the resources that are available to meet the needs of disadvantaged groups, contribute to unequal outcomes, and reinforce implicit bias. Recent data suggest slow progress in many areas but have documented a few notable successes in eliminating these disparities. To eliminate these disparities, continued progress will require a collective national will to ensure health care equity through expanded health insurance coverage, support for primary care, and public accountability based on progress toward defined, time-limited objectives using evidence-based, sufficiently resourced, multilevel quality improvement strategies that engage patients, clinicians, health care organizations, and communities. PMID:26789384

  10. Stereo Matching by Filtering-Based Disparity Propagation.

    PubMed

    Wang, Xingzheng; Tian, Yushi; Wang, Haoqian; Zhang, Yongbing

    2016-01-01

    Stereo matching is essential and fundamental in computer vision tasks. In this paper, a novel stereo matching algorithm based on disparity propagation using edge-aware filtering is proposed. By extracting disparity subsets for reliable points and customizing the cost volume, the initial disparity map is refined through filtering-based disparity propagation. Then, an edge-aware filter with low computational complexity is adopted to formulate the cost column, which makes the proposed method independent on the local window size. Experimental results demonstrate the effectiveness of the proposed scheme. Bad pixels in our output disparity map are considerably decreased. The proposed method greatly outperforms the adaptive support-weight approach and other conditional window-based local stereo matching algorithms. PMID:27626800

  11. Quality of care and racial health disparities: a strategic overview.

    PubMed

    Chassin, Mark R; Anderson, Rebecca M

    2008-01-01

    Substantial racial and ethnic disparities in health and health care exist in the United States. The Department of Health Policy at the Mount Sinai School of Medicine has developed a strategy for reducing those disparities that builds upon its quality improvement experience. This article discusses the utility of applying quality improvement principles to the development of interventions to eliminate underuse of effective treatments and reduce the disparities that may arise from this quality problem. We present a conceptual model of racial disparities in health and our underuse hypothesis. Parallels between our disparities research strategy and six sigma quality improvement methods are described. Finally, the article provides an example of how we have been able to successfully implement proven-effective health improvement programs in the Harlem community even after grant funding has ended. PMID:18306237

  12. Radiocarbon-Based Source Apportionment of the Water-Soluble Organic Carbon (wsoc) of Atmospheric Aerosols in South and East Asia

    NASA Astrophysics Data System (ADS)

    Kirillova, E. N.; Sheesley, R. J.; Andersson, A.; Gustafsson, O.; Safai, P. D.; Budhavant, K.; Rao, P. S.; Kang, E.; Han, J.; Lee, M.

    2011-12-01

    The air quality and regional climate in South and East Asia are considerably affected by atmospheric aerosols produced by anthropogenic activities. Recent studies have investigated the sources of the black carbon aerosol component in these regions. This study seeks to make progress in apportioning the sources of the water soluble organic carbon (WSOC) component, which makes up 20-65% of the carbonaceous aerosol mass in these areas. WSOC is important as it enhances the ability of particles to serve as cloud condensation nuclei (CCN) and, therefore, has an impact on regional climate and radiative forcing. Atmospheric particulate matter was collected during fifteen-month continuous sampling campaigns Jan 2008 - March 2009 at both the Maldives Climate Observatory at Hannimaadho (MCOH) and at the Sinhagad hilltop sampling site of the Indian Institute of Tropical Meteorology (SIN) in central-western India. The radiocarbon method is an ideal approach to identify fossil sources (14C "dead") compared to biogenic and biomass combustion products (with a contemporary 14C signal). WSOC is a large fraction of organic aerosols and its annual average contribution to TOC during 2008 is 26% at MCOH and 40% at SIN. There is a distinct seasonal variability in WSOC concentrations at both sites with high concentrations during the winter season (0.92±0.49μg m-3 at MCOH and 3.5±2.0μg m-3 at SIN) and very low concentrations during the summer monsoon season (0.08±0.04μg m-3 at MCOH and 0.27±0.20μg m-3 at SIN). The radiocarbon source apportionment of WSOC in winter dry season was similar at MCOH and SIN with 80-85% from biogenic/biomass combustion and the rest from fossil fuel precursors. For the rest of the year, the biogenic/biomass contribution to WSOC is higher at the Indian Ocean site (86-93%) compared to the Indian site (74-83%). In March 2011 the GoPoEx2011 intensive sampling campaign at the Gosan ABC Superstation, Jeju Island, South Korea was dedicated to study atmospheric

  13. Health Disparities and Cancer: Racial Disparities in Cancer Mortality in the United States, 2000–2010

    PubMed Central

    O’Keefe, Eileen B.; Meltzer, Jeremy P.; Bethea, Traci N.

    2015-01-01

    Declining cancer incidence and mortality rates in the United States (U.S.) have continued through the first decade of the twenty-first century. Reductions in tobacco use, greater uptake of prevention measures, adoption of early detection methods, and improved treatments have resulted in improved outcomes for both men and women. However, Black Americans continue to have the higher cancer mortality rates and shorter survival times. This review discusses and compares the cancer mortality rates and mortality trends for Blacks and Whites. The complex relationship between socioeconomic status and race and its contribution to racial cancer disparities is discussed. Based on current trends and the potential and limitations of the patient protection and affordable care act with its mandate to reduce health care inequities, future trends, and challenges in cancer mortality disparities in the U.S. are explored. PMID:25932459

  14. Health disparities and cancer: racial disparities in cancer mortality in the United States, 2000-2010.

    PubMed

    O'Keefe, Eileen B; Meltzer, Jeremy P; Bethea, Traci N

    2015-01-01

    Declining cancer incidence and mortality rates in the United States (U.S.) have continued through the first decade of the twenty-first century. Reductions in tobacco use, greater uptake of prevention measures, adoption of early detection methods, and improved treatments have resulted in improved outcomes for both men and women. However, Black Americans continue to have the higher cancer mortality rates and shorter survival times. This review discusses and compares the cancer mortality rates and mortality trends for Blacks and Whites. The complex relationship between socioeconomic status and race and its contribution to racial cancer disparities is discussed. Based on current trends and the potential and limitations of the patient protection and affordable care act with its mandate to reduce health care inequities, future trends, and challenges in cancer mortality disparities in the U.S. are explored. PMID:25932459

  15. AMS Radiocarbon Dating of Large Za Baobabs (Adansonia za) of Madagascar

    PubMed Central

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

    2016-01-01

    The article reports the radiocarbon investigation of Anzapalivoro, the largest za baobab (Adansonia za) specimen of Madagascar and of another za, namely the Big cistern baobab. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. For samples collected from the cavity walls, the age values increase with the distance into the wood up to a point of maximum age, after which the values decrease toward the outer part. This anomaly of age sequences indicates that the inner cavity of Anzapalivoro is a false cavity, practically an empty space between several fused stems disposed in a ring-shaped structure. The radiocarbon date of the oldest sample was 780 ± 30 bp, which corresponds to a calibrated age of around 735 yr. Dating results indicate that Anzapalivoro has a closed ring-shaped structure, which consists of 5 fused stems that close a false cavity. The oldest part of the biggest za baobab has a calculated age of 900 years. We also disclose results of the investigation of a second za baobab, the Big cistern baobab, which was hollowed out for water storage. This specimen, which consists of 4 fused stems, was found to be around 260 years old. PMID:26760300

  16. African Baobabs with False Inner Cavities: The Radiocarbon Investigation of the Lebombo Eco Trail Baobab

    PubMed Central

    Patrut, Adrian; Woodborne, Stephan; von Reden, Karl F.; Hall, Grant; Hofmeyr, Michele; Lowy, Daniel A.; Patrut, Roxana T.

    2015-01-01

    The article reports the radiocarbon investigation results of the Lebombo Eco Trail tree, a representative African baobab from Mozambique. Several wood samples collected from the large inner cavity and from the outer part of the tree were investigated by AMS radiocarbon dating. According to dating results, the age values of all samples increase from the sampling point with the distance into the wood. For samples collected from the cavity walls, the increase of age values with the distance into the wood (up to a point of maximum age) represents a major anomaly. The only realistic explanation for this anomaly is that such inner cavities are, in fact, natural empty spaces between several fused stems disposed in a ring-shaped structure. We named them false cavities. Several important differences between normal cavities and false cavities are presented. Eventually, we dated other African baobabs with false inner cavities. We found that this new architecture enables baobabs to reach large sizes and old ages. The radiocarbon date of the oldest sample was 1425 ± 24 BP, which corresponds to a calibrated age of 1355 ± 15 yr. The dating results also show that the Lebombo baobab consists of five fused stems, with ages between 900 and 1400 years; these five stems build the complete ring. The ring and the false cavity closed 800–900 years ago. The results also indicate that the stems stopped growing toward the false cavity over the past 500 years. PMID:25621989

  17. Radiocarbon dating of a pine tree (Pinus densiflora) from Yeongwol, Korea

    NASA Astrophysics Data System (ADS)

    Kim, C. H.; Lee, J. H.; Kang, J.; Song, S.; Yun, M. H.; Kim, J. C.

    2015-10-01

    We report the results of the dating of a pine tree (Pinus densiflora) from Yeongwol, Korea. The age of the tree was estimated to be in the range of hundreds of years, however, the tree had been broken by a strong wind in March 2010 and now only the stump of the tree is left. At the time of sampling in 2014, there were several decayed parts in the stump, so using the usual dendrochronological method (i.e. ring counting) for dating was difficult. However, we found a small wood sample with tree rings near the center of the stump that could be used for radiocarbon wiggle-match dating. Radiocarbon dates were determined using Accelerator mass spectrometry (AMS). The IntCal13 curve was used to calibrate the radiocarbon dates, and the wiggle matching technique was used to reduce the error of the calibrated ages. Based on the dating results, we suggest that the pine tree is approximately 300 years or older.

  18. 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. PMID:25863698

  19. AMS Radiocarbon Dating of Large Za Baobabs (Adansonia za) of Madagascar.

    PubMed

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

    2016-01-01

    The article reports the radiocarbon investigation of Anzapalivoro, the largest za baobab (Adansonia za) specimen of Madagascar and of another za, namely the Big cistern baobab. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. For samples collected from the cavity walls, the age values increase with the distance into the wood up to a point of maximum age, after which the values decrease toward the outer part. This anomaly of age sequences indicates that the inner cavity of Anzapalivoro is a false cavity, practically an empty space between several fused stems disposed in a ring-shaped structure. The radiocarbon date of the oldest sample was 780 ± 30 bp, which corresponds to a calibrated age of around 735 yr. Dating results indicate that Anzapalivoro has a closed ring-shaped structure, which consists of 5 fused stems that close a false cavity. The oldest part of the biggest za baobab has a calculated age of 900 years. We also disclose results of the investigation of a second za baobab, the Big cistern baobab, which was hollowed out for water storage. This specimen, which consists of 4 fused stems, was found to be around 260 years old. PMID:26760300

  20. African baobabs with false inner cavities: the radiocarbon investigation of the Lebombo Eco Trail baobab.

    PubMed

    Patrut, Adrian; Woodborne, Stephan; von Reden, Karl F; Hall, Grant; Hofmeyr, Michele; Lowy, Daniel A; Patrut, Roxana T

    2015-01-01

    The article reports the radiocarbon investigation results of the Lebombo Eco Trail tree, a representative African baobab from Mozambique. Several wood samples collected from the large inner cavity and from the outer part of the tree were investigated by AMS radiocarbon dating. According to dating results, the age values of all samples increase from the sampling point with the distance into the wood. For samples collected from the cavity walls, the increase of age values with the distance into the wood (up to a point of maximum age) represents a major anomaly. The only realistic explanation for this anomaly is that such inner cavities are, in fact, natural empty spaces between several fused stems disposed in a ring-shaped structure. We named them false cavities. Several important differences between normal cavities and false cavities are presented. Eventually, we dated other African baobabs with false inner cavities. We found that this new architecture enables baobabs to reach large sizes and old ages. The radiocarbon date of the oldest sample was 1425 ± 24 BP, which corresponds to a calibrated age of 1355 ± 15 yr. The dating results also show that the Lebombo baobab consists of five fused stems, with ages between 900 and 1400 years; these five stems build the complete ring. The ring and the false cavity closed 800-900 years ago. The results also indicate that the stems stopped growing toward the false cavity over the past 500 years. PMID:25621989

  1. Radiocarbon AMS determination of the biogenic component in CO 2 emitted from waste incineration

    NASA Astrophysics Data System (ADS)

    Calcagnile, L.; Quarta, G.; D'Elia, M.; Ciceri, G.; Martinotti, V.

    2011-12-01

    The thermal utilization of waste for energy production is gaining importance in European countries. Nevertheless, the combustion of waste leads to significant CO 2 emissions in the atmosphere which, depending on the fraction of biogenic and fossil materials, have to be only partially accounted for the national greenhouse gas inventory. For this reason the development of proper methodologies for the measurement of the biogenic fraction in the combusted waste is an active research field. In fact the determination of the radiocarbon concentration in the carbon dioxide stack emissions allows to have a direct indication of the biogenic component in the burned fuel. We present the results of the AMS radiocarbon analyses carried out on carbon dioxide sampled at the stack of three power plants located in Northern Italy burning natural gas, landfill biogas and SRF (Solid Recovered Fuel) derived from MSW (Municipal Solid Waste). The sampling apparatus and the applied processing protocols are described together with the calculation procedures used to determine, from the measured radiocarbon concentrations, the proportion of biogenic and fossil component in the flue gas and in the combusted fuel. The results confirm the high potentialities of this approach in the analysis of industrial CO 2 emissions.

  2. Performance report for the low energy compact radiocarbon accelerator mass spectrometer at Uppsala University

    NASA Astrophysics Data System (ADS)

    Salehpour, M.; Håkansson, K.; Possnert, G.; Wacker, L.; Synal, H.-A.

    2016-03-01

    A range of ion beam analysis activities are ongoing at Uppsala University, including Accelerator Mass Spectrometry (AMS). Various isotopes are used for AMS but the isotope with the widest variety of applications is radiocarbon. Up until recently, only the 5 MV Pelletron tandem accelerator had been used at our site for radiocarbon AMS, ordinarily using 12 MeV 14,13,12C3+ ions. Recently a new radiocarbon AMS system, the Green-MICADAS, developed at the ion physics group at ETH Zurich, was installed. The system has a number of outstanding features which will be described. The system operates at a terminal voltage of 175 kV and uses helium stripper gas, extracting singly charged carbon ions. The low- and high energy mass spectrometers in the system are stigmatic dipole permanent magnets (0.42 and 0.97 T) requiring no electrical power nor cooling water. The system measures both the 14C/12C and the 13C/12C ratios on-line. Performance of the system is presented for both standard mg samples as well as μg-sized samples.

  3. Radiocarbon dating of fluvial organic matter reveals land-use impacts in boreal peatlands.

    PubMed

    Hulatt, Chris J; Kaartokallio, Hermanni; Oinonen, Markku; Sonninen, Eloni; Stedmon, Colin A; Thomas, David N

    2014-11-01

    This study measured the effects of land use on organic matter released to surface waters in a boreal peat catchment using radiocarbon dating of particulate and dissolved organic carbon (POC and DOC), DOC concentration, stable carbon and nitrogen isotope composition, and optical measurements. Undisturbed sites invariably released modern DOC and POC (<20 years old), and seasonal forcing had little impact on the age distribution. Release of pre-1950 carbon was detected at peat extraction, agricultural and drained sites, and was consistently observed at agricultural and peat extraction areas throughout the seasons. Conventional mean DOC ages reached 3,100 (±122) years before collection. On average, DOC concentrations were up to 38% higher at impacted sites compared to natural areas, but there was no significant effect of land use on surface water DOC concentrations. The study indicates that the true extent of land use impacts is not necessarily detectible through changes in DOC concentration alone: Radiocarbon dating was essential to show that leaching of old soil organic matter at modified sites had replaced, rather than supplemented, the modern DOM that is usually released from pristine peatlands. Relationships between the specific fluorescence intensity of DOM and its radiocarbon age were identified, indicating that optical techniques may provide a method for the detection of changes in DOM age. PMID:25260159

  4. Influence of matrix diffusion and exchange reactions on radiocarbon ages in fissured carbonate aquifers

    SciTech Connect

    Maloszewski, P. ); Zuber, A. )

    1991-08-01

    The parallel fissure model coupled with the equation of diffusion into the matrix and with exchange reaction equations has been used to derive a simple formula for estimating the influence of matrix porosity and reaction parameters on the determination of radiocarbon ages in fissured carbonate rocks. Examples of evidently too great radiocarbon ages in carbonate formations, which are not explainable by models for the initial {sup 14}C corrections, can easily be explained by this formula. Parameters obtained for a chalk formation from a known multitracer experiment combined with a pumping test suggest a possibility of {sup 14}C ages more than three orders of magnitude greater than the ages which would be observed if the radiocarbon transport took place only in the mobile water in the fissures. It is shown that contrary to the solute movement on a small scale and with a variable input, the large-scale movement, characteristic for the {sup 14}C dating, does not necessarily require the knowledge of kinetic parameters, because they may be replaced by the distribution coefficient. Discordant tritium and {sup 14}C concentrations are commonly interpreted as a proof of mixing either in the aquifer or at the discharge site. For fissured carbonate formations, however, an alternative explanation is given by the derived model showing a considerable delay of {sup 14}C with respect to nonsorbable tracers.

  5. Gas chromatographic isolation of individual compounds from complex matrices for radiocarbon dating

    SciTech Connect

    Eglinton, T.I.; Aluwihare, L.I.; McNichol, A.P.; Bauer, J.E.; Druffel, E.R.M.

    1996-03-01

    This paper describes the application of a novel, practical approach for isolation of individual compounds from complex organic matrices for natural abundance radiocarbon measurement. This is achieved through the use of automated pereparative capillary gas chromatography (PCGC) to separate and recover sufficient quantities of individual target compounds for {sup 14}C analysis by accelerator mass spectrometry (AMS). We developed and tested this approach using a suite of samples (plant lipids, petroleums) whose ages spanned the {sup 14}C time scale and which contained a variety of compound types (fatty acids, sterols, hydrocarbons). Comparison of individual compound and bulk radiocarbon signatures for the isotopically homogeneous samples studied revealed that {Delta}{sup 14}C values generally agreed well ({+-}10%). Background contamination was assessed at each stage of the isolation procedure, and incomplete solvent removal prior to combustion was the only significant source of additional carbon. Isotope fractionation was addressed through compound-specific stable carbon isotopic analyses. Fractionation of isotopes during isolation of individual compounds was minimal (<5% for {delta}{sup 13}C), provided the entire peak was collected during PCGC. Trapping of partially coeluting peaks did cause errors, and these results highlight the importance of conducting stable carbon isotopic measurements of each trapped compound in concert with AMS for reliable radiocarbon measurements. 29 refs., 9 figs., 2 tabs.

  6. Extracting growth rates from the non-laminated coralline sponge Astrosclera willeyana using "bomb" radiocarbon

    SciTech Connect

    Fallon, S; Guilderson, T

    2004-06-30

    Coralline sponges have the potential to fill in gaps in our understanding of subsurface oceanographic variability. However, one disadvantage they have compared to hermatypic reef building coral proxies is that they do not have annual density bands and need to be radiometrically dated for an age determination. To elucidate growth rate variability we have measured radiocarbon in 1 mm increments from Astrosclera willeyana sponges collected off the Central and Northern Great Barrier Reef (GBR) and from Truk in the Caroline Islands and compared these radiocarbon profiles to independently dated coral radiocarbon records. Growth rates of the GBR sponges average 1.2 {+-} 0.3 and 1.0 {+-} 0.3 mm yr{sup -1}, north and central respectively but can vary by a factor of two. The growth rate of the Truk sponge averages 1.2 {+-} 0.1 mm yr{sup -1}. These growth rates are significantly faster to those measured for other GBR Astrosclera willeyana sponges (0.2 mm yr{sup -1}) by Calcein staining (Woerheide 1988).

  7. Geographic isolates of Lymantria dispar multiple nucleopolyhedrovirus: Genome sequence analysis and pathogenicity against European and Asian gypsy moth strains.

    PubMed

    Harrison, Robert L; Rowley, Daniel L; Keena, Melody A

    2016-06-01

    Isolates of the baculovirus species Lymantria dispar multiple nucleopolyhedrovirus have been formulated and applied to suppress outbreaks of the gypsy moth, L. dispar. To evaluate the genetic diversity in this species at the genomic level, the genomes of three isolates from Massachusetts, USA (LdMNPV-Ab-a624), Spain (LdMNPV-3054), and Japan (LdMNPV-3041) were sequenced and compared with four previously determined LdMNPV genome sequences. The LdMNPV genome sequences were collinear and contained the same homologous repeats (hrs) and clusters of baculovirus repeat orf (bro) gene family members in the same relative positions in their genomes, although sequence identities in these regions were low. Of 146 non-bro ORFs annotated in the genome of the representative isolate LdMNPV 5-6, 135 ORFs were found in every other LdMNPV genome, including the 37 core genes of Baculoviridae and other genes conserved in genus Alphabaculovirus. Phylogenetic inference with an alignment of the core gene nucleotide sequences grouped isolates 3041 (Japan) and 2161 (Korea) separately from a cluster containing isolates from Europe, North America, and Russia. To examine phenotypic diversity, bioassays were carried out with a selection of isolates against neonate larvae from three European gypsy moth (Lymantria dispar dispar) and three Asian gypsy moth (Lymantria dispar asiatica and Lymantria dispar japonica) colonies. LdMNPV isolates 2161 (Korea), 3029 (Russia), and 3041 (Japan) exhibited a greater degree of pathogenicity against all L. dispar strains than LdMNPV from a sample of Gypchek. This study provides additional information on the genetic diversity of LdMNPV isolates and their activity against the Asian gypsy moth, a potential invasive pest of North American trees and forests. PMID:27090923

  8. Do wealth disparities contribute to health disparities within racial/ethnic groups?

    PubMed Central

    Pollack, Craig Evan; Cubbin, Catherine; Sania, Ayesha; Hayward, Mark; Vallone, Donna; Flaherty, Brian; Braveman, Paula A.

    2013-01-01

    Background Though wide disparities in wealth have been documented across racial/ethnic groups, it is largely unknown whether differences in wealth are associated with health disparities within racial/ethnic groups. Methods Data from the Survey of Consumer Finances (2004, ages 25–64) and the Health and Retirement Survey (2004, ages 50+), containing a wide range of assets and debts variables, was used to calculate net worth (a standard measure of wealth). Among non-Hispanic black, Hispanic, and non-Hispanic white populations, we tested whether wealth was associated with self-reported poor/fair health status after accounting for income and education. Results Except among the younger Hispanic population, net worth was significantly associated with poor/fair health status within each racial/ethnic group in both datasets. Adding net worth attenuated the association between education and poor/fair health (in all racial/ethnic groups) and between income and poor/fair health (except among older Hispanics). Conclusions The results add to literature indicating the importance of including measures of wealth in health research for what they may reveal about disparities not only between but also within different racial/ethnic groups. PMID:23427209

  9. Overcoming the Triad of Rural Health Disparities: How Local Culture, Lack of Economic Opportunity, and Geographic Location Instigate Health Disparities

    ERIC Educational Resources Information Center

    Thomas, Tami L.; DiClemente, Ralph; Snell, Samuel

    2014-01-01

    Objective: To discuss how the effects of culture, economy, and geographical location intersect to form a gestalt triad determining health-related disparities in rural areas. Methods: We critically profile each component of the deterministic triad in shaping current health-related disparities in rural areas; evaluate the uniquely composed…

  10. The challenges of transdisciplinary research in health disparities: the early experiences of the centers for population health and health disparities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2003, NIH funded 8 Centers for Population Health and Health Disparities (CPHHD). The mission of these centers is to understand and reduce health disparities using a transdisciplinary approach with community partners as co-investigators. The present study aims to identify early challenges experi...

  11. Radiocarbon dates and late-Quaternary stratigraphy from Mamontova Gora, unglaciated central Yakutia, Siberia, U.S.S.R.

    USGS Publications Warehouse

    Pewe, T.L.; Journaux, A.; Stuckenrath, R.

    1977-01-01

    A fine exposure of perennially frozen ice-rich silt and associated flora and vertebrate fauna of late-Quaternary age exists at Mamontova Gora along the Aldan River in central Yakutia, Siberia, U.S.S.R. The silt deposit caps a 50-m-high terrace and consists of three units. An upper layer 1-2 m thick overlies a 10-15-m-thick brownish to black silt layer. The lower silt layer is greenish to gray and about 15 m thick. All the silt is well sorted with 60% of the particles falling between 0.005 and 0.5 mm in diameter and is generally chemically and mineralogically homogeneous. The middle unit contains may extinct vertebrate mammal remains and ice wedges. The lower unit contains little vegetation and no ice wedges. The silt is widespread and exists as a loamy blanket on terraces at various elevations on both sides of the lower Aldan River. The origin of the silt blanket of late-Quaternary age in central Yakutia has long been controversial. Various hypotheses have been suggested, including lacustrine and alluvial, as well as frost-action origins. It is sometimes referred to as loess-like loam. Pe??we?? believes the silt at Mamontova Gora is loess, some of which has been retransported very short distances by water. The silt probably was blown from wide, braided, unvegetated flood plains of rivers draining nearby glaciers. The silt deposits are late Quaternary in age and probably associated with the Maximum glaciation (Samarov) and Sartan and Syryan glaciations of Wisconsinan age. On the basis of biostratigraphy, 10 radiocarbon dates, and their relation to the nearby glacial record, it is felt that the upper unit at Mamontova Gora is Holocene and the middle unit is Wisconsinan. The youngest date available from the middle unit at this particular location is 26,000 years. Dates greater than 56,000 years were obtained in the lower part of the middle unit. The lower unit is definitely beyond the range of radiocarbon dating and probably is older than the last interglacial. The

  12. Accelerator Mass Spectrometric determination of radiocarbon in stratospheric CO2, retrieved from AirCore sampling.

    NASA Astrophysics Data System (ADS)

    Paul, Dipayan; Been, Henk A.; Chen, Huilin; Kivi, Rigel; Meijer, Harro A. J.

    2015-04-01

    In this decade, understanding the impact of human activities on climate is one of the key issues of discussion globally. The continuous rise in the concentration of greenhouse gases, e.g., CO2, CH4, etc. in the atmosphere, predominantly due to human activities, is alarming and requires continuous monitoring to understand the dynamics. Radiocarbon is an important atmospheric tracer and one of the many used in the understanding of the global carbon budget, which includes the greenhouse gases like CO2 and CH4. Measurement of 14C (or radiocarbon) in atmospheric CO2 generally requires collection of large air samples (few liters) from which CO2 is extracted and then the concentration of radiocarbon is determined. Currently, Accelerator Mass Spectrometry (AMS) is the most precise, reliable and widely used technique for atmospheric radiocarbon detection. However, the regular collection of air samples from troposphere and stratosphere, for example using aircraft, is prohibitively expensive. AirCore is an innovative atmospheric sampling system, developed by NOAA. It comprises of a long tube descending from a high altitude with one end open and the other closed, and has been demonstrated to be a reliable, cost-effective sampling system for high-altitude profile (up to ~ 30 km) measurements of CH4and CO2(Karion et al. 2010). In Europe, AirCore measurements are being performed on a regular basis near Sodankylä since September 2013. Here we describe the analysis of two such AirCore samples collected in July 2014, Finland, for determining the 14C concentration in stratospheric CO2. The two AirCore samples were collected on consecutive days. Each stratospheric AirCore sample was divided into six fractions, each containing ~ 35 μg CO2 (~9.5 μg C). Each fraction was separately trapped in 1 /4 inch coiled stainless steel tubing for radiocarbon measurements. The procedure for CO2 extraction from the stratospheric air samples; the sample preparation, with samples containing < 10

  13. Reconciling radiocarbon and ice core timescales over the Holocene - Cosmogenic radionuclides as synchronization tools

    NASA Astrophysics Data System (ADS)

    Muscheler, R.; Adolphi, F.; Mekhaldi, F.

    2015-12-01

    The atmospheric production rates of cosmogenic radionuclides, such as 14C and 10Be, vary globally due to external processes, namely the solar and geomagnetic modulation of the galactic cosmic ray flux as well as solar proton events. This signature is recorded in various archives such as ice cores (10Be) and tree-rings (14C). Hence, cosmogenic radionuclides offer a means to continuously assess timescale differences between two of the most widely used timescales in paleoclimatology - the radiocarbon and the ice core timescales. Short lived solar proton events additionally provide distinct marker horizons that allow synchronization of discrete horizons at annual precision. We will present a cosmogenic radionuclide based synchronization of the Greenland ice core timescale (GICC05, Svensson et al., 2008) and the radiocarbon timescale (IntCal13, Reimer et al., 2013) over the Holocene. This synchronization allows radiocarbon dated and ice core paleoclimate records to be compared on a common timescale at down to sub-decadal precision. We will compare these results to independent discrete isochrones obtained from tephrochronology and solar proton events. In addition, we will discuss implications for the accuracy and uncertainty estimates of GICC05 over the Holocene. Reimer, P. J., Bard, E., Bayliss, A., Beck, J. W., Blackwell, P. G., Bronk Ramsey, C., Buck, C. E., Cheng, H., Edwards, R. L., Friedrich, M., Grootes, P. M., Guilderson, T. P., Haflidason, H., Hajdas, I., Hatté, C., Heaton, T. J., Hoffmann, D. L., Hogg, A. G., Hughen, K. A., Kaiser, K. F., Kromer, B., Manning, S. W., Niu, M., Reimer, R. W., Richards, D. A., Scott, E. M., Southon, J. R., Staff, R. A., Turney, C. S. M., and van der Plicht, J.: IntCal13 and Marine13 Radiocarbon Age Calibration Curves 0-50,000 Years cal BP, Radiocarbon, 55, 1869-1887, 10.2458/azu_js_rc.55.16947, 2013. Svensson, A., Andersen, K. K., Bigler, M., Clausen, H. B., Dahl-Jensen, D., Davies, S. M., Johnsen, S. J., Muscheler, R., Parrenin

  14. Radiocarbon evidence for alternating northern and southern sources of ventilation of the deep Atlantic carbon pool during the last deglaciation.

    PubMed

    Skinner, Luke C; Waelbroeck, Claire; Scrivner, Adam E; Fallon, Stewart J

    2014-04-15

    Recent theories for glacial-interglacial climate transitions call on millennial climate perturbations that purged the deep sea of sequestered carbon dioxide via a "bipolar ventilation seesaw." However, the viability of this hypothesis has been contested, and robust evidence in its support is lacking. Here we present a record of North Atlantic deep-water radiocarbon ventilation, which we compare with similar data from the Southern Ocean. A striking coherence in ventilation changes is found, with extremely high ventilation ages prevailing across the deep Atlantic during the last glacial period. The data also reveal two reversals in the ventilation gradient between the deep North Atlantic and Southern Ocean during Heinrich Stadial 1 and the Younger Dryas. These coincided with periods of sustained atmospheric CO2 rise and appear to have been driven by enhanced ocean-atmosphere exchange, primarily in the Southern Ocean. These results confirm the operation of a bipolar ventilation seesaw during deglaciation and underline the contribution of abrupt regional climate anomalies to longer-term global climate transitions. PMID:24706801

  15. Source Contributions to Wintertime Elemental and Organic Carbon in the Western Arctic Based on Radiocarbon and Tracer Apportionment.

    PubMed

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

    2015-10-01

    To quantify the contributions of fossil and biomass sources to the wintertime Arctic aerosol burden source apportionment is reported for elemental (EC) and organic carbon (OC) fractions of six PM10 samples collected during a wintertime (2012-2013) campaign in Barrow, AK. Radiocarbon apportionment of EC indicates that fossil sources contribute an average of 68 ± 9% (0.01-0.07 μg m(-3)) in midwinter decreasing to 49 ± 6% (0.02 μg m(-3)) in late winter. The mean contribution of fossil sources to OC for the campaign was stable at 38 ± 8% (0.04-0.32 μg m(-3)). Samples were also analyzed for organic tracers, including levoglucosan, for use in a chemical mass balance (CMB) source apportionment model. The CMB model was able to apportion 24-53% and 99% of the OC and EC burdens, respectively, during the campaign, with fossil OC contributions ranging from 25 to 74% (0.02-0.09 μg m(-3)) and fossil EC contributions ranging from 73 to 94% (0.03-0.07 μg m(-3)). Back trajectories identified two major wintertime source regions to Barrow: the Russian and North American Arctic. Atmospheric lifetimes of levoglucosan, ranging from 50 to 320 h, revealed variability in wintertime atmospheric processing of this biomass burning tracer. This study allows for unambiguous apportionment of EC to fossil fuel and biomass combustion sources and intercomparison with CMB modeling. PMID:26325404

  16. Direct radiocarbon dates for Vindija G1 and Velika Pećina Late Pleistocene hominid remains

    PubMed Central

    Smith, Fred H.; Trinkaus, Erik; Pettitt, Paul B.; Karavanić, Ivor; Paunović, Maja

    1999-01-01

    New accelerator mass spectrometry radiocarbon dates taken directly on human remains from the Late Pleistocene sites of Vindija and Velika Pećina in the Hrvatsko Zagorje of Croatia are presented. Hominid specimens from both sites have played critical roles in the development of current perspectives on modern human evolutionary emergence in Europe. Dates of ≈28 thousand years (ka) before the present (B.P.) and ≈29 ka B.P. for two specimens from Vindija G1 establish them as the most recent dated Neandertals in the Eurasian range of these archaic humans. The human frontal bone from Velika Pećina, generally considered one of the earliest representatives of modern humans in Europe, dated to ≈5 ka B.P., rendering it no longer pertinent to discussions of modern human origins. Apart from invalidating the only radiometrically based example of temporal overlap between late Neandertal and early modern human fossil remains from within any region of Europe, these dates raise the question of when early modern humans first dispersed into Europe and have implications for the nature and geographic patterning of biological and cultural interactions between these populations and the Neandertals. PMID:10535913

  17. Radiocarbon evidence for alternating northern and southern sources of ventilation of the deep Atlantic carbon pool during the last deglaciation

    PubMed Central

    Skinner, Luke C.; Waelbroeck, Claire; Scrivner, Adam E.; Fallon, Stewart J.

    2014-01-01

    Recent theories for glacial–interglacial climate transitions call on millennial climate perturbations that purged the deep sea of sequestered carbon dioxide via a “bipolar ventilation seesaw.” However, the viability of this hypothesis has been contested, and robust evidence in its support is lacking. Here we present a record of North Atlantic deep-water radiocarbon ventilation, which we compare with similar data from the Southern Ocean. A striking coherence in ventilation changes is found, with extremely high ventilation ages prevailing across the deep Atlantic during the last glacial period. The data also reveal two reversals in the ventilation gradient between the deep North Atlantic and Southern Ocean during Heinrich Stadial 1 and the Younger Dryas. These coincided with periods of sustained atmospheric CO2 rise and appear to have been driven by enhanced ocean–atmosphere exchange, primarily in the Southern Ocean. These results confirm the operation of a bipolar ventilation seesaw during deglaciation and underline the contribution of abrupt regional climate anomalies to longer-term global climate transitions. PMID:24706801

  18. Marine radiocarbon reservoir corrections (∆R) for Chesapeake Bay and the Middle Atlantic Coast of North America

    NASA Astrophysics Data System (ADS)

    Rick, Torben C.; Henkes, Gregory A.; Lowery, Darrin L.; Colman, Steven M.; Culleton, Brendan J.

    2012-01-01

    Radiocarbon dates from known age, pre-bomb eastern oyster (Crassostrea virginica) shells provide local marine reservoir corrections (∆R) for Chesapeake Bay and the Middle Atlantic coastal area of eastern North America. These data suggest subregional variability in ∆R, ranging from 148 ± 46 14C yr on the Potomac River to - 109 ± 38 14C yr at Swan Point, Maryland. The ∆R weighted mean for the Chesapeake's Western Shore (129 ± 22 14C yr) is substantially higher than the Eastern Shore (- 88 ± 23 14C yr), with outer Atlantic Coast samples falling between these values (106 ± 46 and 2 ± 46 14C yr). These differences may result from a combination of factors, including 14C-depleted freshwater that enters the bay from some if its drainages, 14C-depleted seawater that enters the bay at its mouth, and/or biological carbon recycling. We advocate using different subregional ∆R corrections when calibrating 14C dates on aquatic specimens from the Chesapeake Bay and coastal Middle Atlantic region of North America.

  19. Ancient Mtdna Sequences And Radiocarbon Dating Of Human Bones From The Chalcolithic Caves Of Wadi El-Makkukh.

    NASA Astrophysics Data System (ADS)

    Salamon, M.; Tzur, S.; Arensburg, B.; Zias, J.; Nagar, Y.; Weiner, S.; Boaretto, E.

    DNA from fossil human bones can provide valuable information for understanding intra- and inter-population relationships. Using the DNA preserved inside crystal aggregates from human fossil bones containing relatively large amounts of collagen, we demonstrate the presence of reproducible mtDNA control region sequences. Radiocarbon dates from each bone show that the burial caves were used for up to 600 years during the Chalcolithic period (5th-4th millennium BP). A comparison of the ancient DNA sequences with modern mtDNA databases indicates that all samples can most likely be assigned to the R haplogroup sub-clades, which are common in West-Eurasia. In four cases more precise and confident haplogroup identifications could be achieved (H, U3a and H6). The H haplogroup is present in three out of the four assigned ancient samples. This haplogroup is prevalent today in West - Eurasia. The results reported here tend to genetically link this Chalcolithic group of individuals to the current West Eurasian populations.

  20. Radiocarbon ages of Holocene Pelado, Guespalapa, and Chichinautzin scoria cones, south of Mexico City: implications for archaeology and future hazards

    NASA Astrophysics Data System (ADS)

    Siebe, Claus; Rodríguez-Lara, Virgilio; Schaaf, Peter; Abrams, Michael

    Pelado, Guespalapa, and Chichinautzin monogenetic scoria cones located within the Sierra del Chichinautzin Volcanic Field (SCVF) at the southern margin of Mexico City were dated by the radiocarbon method at 10,000, 2,800-4,700, and 1,835 years b.p., respectively. Most previous research in this area was concentrated on Xitle scoria cone, whose lavas destroyed and buried the pre-Hispanic town of Cuicuilco around 1,665+/-35 years b.p. The new dates indicate that the recurrence interval for monogenetic eruptions in the central part of the SCVF and close to the vicinity of Mexico City is <2,500 years. If the entire SCVF is considered, the recurrence interval is <1,700 years. Based on fieldwork and Landsat imagery interpretation a geologic map was produced, morphometric parameters characterizing the cones and lava flows determined, and the areal extent and volumes of erupted products estimated. The longest lava flow was produced by Guespalapa and reached 24 km from its source; total areas covered by lava flows from each eruption range between 54 (Chichinautzin) and 80 km2 (Pelado); and total erupted volumes range between 1 and 2 km3/cone. An average eruption rate for the entire SCVF was estimated at 0.6 km3/1,000 years. These findings are of importance for archaeological as well as volcanic hazards studies in this heavily populated region.

  1. Compound-specific radiocarbon analysis to evaluate the contribution of Peace River floodings to the PAH background in the Peace-Athabasca Delta

    NASA Astrophysics Data System (ADS)

    Jautzy, J. J.; Ahad, J. M.; Hall, R. I.; Wiklund, J. A.; Gobeil, C.; Savard, M. M.

    2013-12-01

    The oil sands of Northern Alberta, Canada are one of the largest hydrocarbon reserves in the world. The rapid growth of the bitumen exploitation in this region involves large scale mining infrastructure, raising questions about the environmental impact of these operations. One of the main issues is the emission of hazardous organic compounds such as polycyclic aromatic hydrocarbons (PAHs). PAHs, which are found naturally in petroleum, are also produced through incomplete combustion and diagenesis of organic matter. The complex nature of the surrounding geology (natural levels of bitumen) requires tools able to discriminate sources of pollutants. The establishment of the PAH background is crucial in order to investigate the impacts of oil sands mining in the Athabasca region. Here we present a new approach to discriminate the sources of alkylated PAHs (fossil or modern biomass) and their relative contributions. Using a dated sediment sequence from a lake situated in the Peace-Athabasca Delta periodically flooded by the Peace River, 6 different groups of parent and alkylated PAHs were extracted and collected by preparative capillary gas chromatography (PCGC) for natural abundance radiocarbon (14C) measurement. Three grouped layers each comprising approximately 10 years of sedimentation and spanning the period of mining operations (i.e., the past 40 years) were analyzed. We report here the first use of 14C measurements on alkylated PAHs extracted from lake sediments. Our results showed low radiocarbon content for all alkylated and parent PAHs analyzed in the three sediment layers. However, a slight trend toward a more modern PAH input can be seen up-core. PAH isomers ratios pointed to a major influence of petroleum input in the entire lake sequence, supporting the predominance of a fossil carbon source as indicated by the low radiocarbon contents. As the Peace River cuts through the Peace oil sands formation, our results can be explained by the main contribution of

  2. 206/207Pb and Radiocarbon: An Unlikely Pair for Identifying the Source and Delivery Time of Ocean Advection in the South China Sea

    NASA Astrophysics Data System (ADS)

    Switzer, A.; Goodkin, N.; Bolton, A.; Chen, M.; Druffel, E. R. M.; Boyle, E. A.

    2015-12-01

    Two independent studies were undertaken to use anthropogenic emissions to investigate natural systems using a massive Porites coral taken from off the coast of Vietnam (12ο12'49.90"N, 109 ο18'17.51"E). Annual uptake of bomb radiocarbon (14CO2) was measured to investigate the impact of coastal upwelling; while Pb/Ca levels and Pb isotopes were measured to investigate oceanic infiltration of anthropogenic Pb. Both records reveal a signal of sub-surface seawater advection from the tropical North Pacific to the South China Sea (SCS) providing independent evidence for the source and delivery time of the upwelled water off the coast of Vietnam. The radiocarbon record, extending from 1900-1986 at ~annual resolution, shows a post-bomb peak lower and broader than those found from other corals in the SCS and Japan, but higher than those found in the Makassar Strait in Indonesia. The Makassar coral experiences three water masses: the South Equatorial Current (SEC), upwelled and SCS water. The SEC has a relatively low radiocarbon content. However, water in the SCS does not mix with SEC water that enters the Indonesia Seas via the Halmahera as the main throughflow is from north to south. Hence, the upwelling signature must be from the North Equatorial Current that enters from the Luzon strait at depth. Leaded gasoline was phased-out between 1997 and 2000 in most Asian countries, however unlike other regional records, the Pb/Ca of the coral continued to increase until 2004 indicating a non-atmospheric source of Pb to the region. Both records indicate the source of upwelled water from the tropical North Pacific at roughly ~100-200 meters with a transport time of >2-5 years. This water is carried westward, via the Luzon Strait and into the South China Sea, where is it upwelled during the summer months. A higher resolution study of this coral combined with other coral records from the region could further narrow the location and timing of the advection and upwelling.

  3. Socially assigned gender nonconformity: A brief measure for use in surveillance and investigation of health disparities

    PubMed Central

    Wylie, Sarah A.; Corliss, Heather L.; Boulanger, Vanessa; Prokop, Lisa A.; Austin, S. Bryn

    2013-01-01

    Discrimination and violence targeting people perceived as gender nonconforming have been linked to a range of negative health outcomes, and large-scale representative data are needed to begin population surveillance of associated health disparities. A brief self-report measure of gender expression as perceived by others was tested using cognitive interviewing methods in a diverse sample of 82 young adults aged 18–30 years, recruited from the New England region in the U.S. Results identified themes related to item clarity, gender expression variation, undesirability of highest or lowest ends of item range, and tension between self and others’ perceptions. The item performed as expected and is recommended for use on studies of health disparities, including statewide and national public health surveillance tools. PMID:24077680

  4. Explaining Racial Disparities in Infant Health in Brazil

    PubMed Central

    Nyarko, Kwame A.; Lopez-Camelo, Jorge; Castilla, Eduardo E.

    2013-01-01

    Objectives. We sought to quantify how socioeconomic, health care, demographic, and geographic effects explain racial disparities in low birth weight (LBW) and preterm birth (PTB) rates in Brazil. Methods. We employed a sample of 8949 infants born between 1995 and 2009 in 15 cities and 7 provinces in Brazil. We focused on disparities in LBW (< 2500 g) and PTB (< 37 gestational weeks) prevalence between infants of African ancestry alone or African mixed with other ancestries, and European ancestry alone. We used a decomposition model to quantify the contributions of conceptually relevant factors to these disparities. Results. The model explained 45% to 94% of LBW and 64% to 94% of PTB disparities between the African ancestry groups and European ancestry. Differences in prenatal care use and geographic location were the most important contributors, followed by socioeconomic differences. The model explained the majority of the disparities for mixed African ancestry and part of the disparity for African ancestry alone. Conclusions. Public policies to improve children’s health should target prenatal care and geographic location differences to reduce health disparities between infants of African and European ancestries in Brazil. PMID:23409894

  5. Partnering health disparities research with quality improvement science in pediatrics.

    PubMed

    Lion, K Casey; Raphael, Jean L

    2015-02-01

    Disparities in pediatric health care quality are well described in the literature, yet practical approaches to decreasing them remain elusive. Quality improvement (QI) approaches are appealing for addressing disparities because they offer a set of strategies by which to target modifiable aspects of care delivery and a method for tailoring or changing an intervention over time based on data monitoring. However, few examples in the literature exist of QI interventions successfully decreasing disparities, particularly in pediatrics, due to well-described challenges in developing, implementing, and studying QI with vulnerable populations or in underresourced settings. In addition, QI interventions aimed at improving quality overall may not improve disparities, and in some cases, may worsen them if there is greater uptake or effectiveness of the intervention among the population with better outcomes at baseline. In this article, the authors review some of the challenges faced by researchers and frontline clinicians seeking to use QI to address health disparities and propose an agenda for moving the field forward. Specifically, they propose that those designing and implementing disparities-focused QI interventions reconsider comparator groups, use more rigorous evaluation methods, carefully consider the evidence for particular interventions and the context in which they were developed, directly engage the social determinants of health, and leverage community resources to build collaborative networks and engage community members. Ultimately, new partnerships between communities, providers serving vulnerable populations, and QI researchers will be required for QI interventions to achieve their potential related to health care disparity reduction. PMID:25560436

  6. Uneven Magnitude of Disparities in Cancer Risks from Air Toxics

    PubMed Central

    James, Wesley; Jia, Chunrong; Kedia, Satish

    2012-01-01

    This study examines race- and income-based disparities in cancer risks from air toxics in Cancer Alley, LA, USA. Risk estimates were obtained from the 2005 National Air Toxics Assessment and socioeconomic and race data from the 2005 American Community Survey, both at the census tract level. Disparities were assessed using spatially weighted ordinary least squares (OLS) regression and quantile regression (QR) for five major air toxics, each with cancer risk greater than 10−6. Spatial OLS results showed that disparities in cancer risks were significant: People in low-income tracts bore a cumulative risk 12% more than those in high-income tracts (p < 0.05), and those in black-dominant areas 16% more than in white-dominant areas (p < 0.01). Formaldehyde and benzene were the two largest contributors to the disparities. Contributions from emission sources to disparities varied by compound. Spatial QR analyses showed that magnitude of disparity became larger at the high end of exposure range, indicating worsened disparity in the poorest and most highly concentrated black areas. Cancer risk of air toxics not only disproportionately affects socioeconomically disadvantaged and racial minority communities, but there is a gradient effect within these groups with poorer and higher minority concentrated segments being more affected than their counterparts. Risk reduction strategies should target emission sources, risk driver chemicals, and especially the disadvantaged neighborhoods. PMID:23208297

  7. Explaining Racial Disparities in Infant Health in Brazil

    PubMed Central

    Nyarko, Kwame A.; Lopez-Camelo, Jorge; Castilla, Eduardo E.

    2015-01-01

    Objectives. We sought to quantify how socioeconomic, health care, demographic, and geographic effects explain racial disparities in low birth weight (LBW) and preterm birth (PTB) rates in Brazil. Methods. We employed a sample of 8949 infants born between 1995 and 2009 in 15 cities and 7 provinces in Brazil. We focused on disparities in LBW (< 2500 g) and PTB (< 37 gestational weeks) prevalence between infants of African ancestry alone or African mixed with other ancestries, and European ancestry alone. We used a decomposition model to quantify the contributions of conceptually relevant factors to these disparities. Results. The model explained 45% to 94% of LBW and 64% to 94% of PTB disparities between the African ancestry groups and European ancestry. Differences in prenatal care use and geographic location were the most important contributors, followed by socioeconomic differences. The model explained the majority of the disparities for mixed African ancestry and part of the disparity for African ancestry alone. Conclusions. Public policies to improve children’s health should target prenatal care and geographic location differences to reduce health disparities between infants of African and European ancestries in Brazil. PMID:26313046

  8. Disability, disparate impact, and class actions.

    PubMed

    Stein, Michael Ashley; Waterstone, Michael E

    2006-12-01

    Following Title VII's enactment, group-based employment discrimination actions flourished due to disparate impact theory and the class action device. Courts recognized that subordination that defined a group's social identity was also sufficient legally to bind members together, even when relief had to be issued individually. Woven through these cases was a notion of panethnicity that united inherently unrelated groups into a common identity, for example, Asian Americans. Stringent judicial interpretation subsequently eroded both legal frameworks and it has become increasingly difficult to assert collective employment actions, even against discriminatory practices affecting an entire group. This deconstruction has immensely disadvantaged persons with disabilities. Under the Americans with Disabilities Act (ADA), individual employee claims to accommodate specific impairments, such as whether to install ramps or replace computer screens, have all but eclipsed a coherent theory of disability-based disparate impact law. Moreover, the class action device has been virtually nonexistent in disability discrimination employment cases. The absence of collective action has been especially harmful because the realm of the workplace is precisely where group-based remedies are needed most. Specifically, a crucial but overlooked issue in disability integration is the harder-to-reach embedded norms that require job and policy modifications. The Article argues that pandisability theory serves as an analogue to earlier notions of panethnicity and provides an equally compelling heuristic for determining class identity. It shows that pandisability undergirds ADA public service and public accommodation class actions in which individualized remedy assessments have been accepted as part of group-based challenges to social exclusion. The Article also demonstrates that this broader vision of collective action is consistent with the history underlying the class action device. Taking

  9. Systematic Review of Health Disparities for Cardiovascular Diseases and Associated Factors among American Indian and Alaska Native Populations

    PubMed Central

    Hutchinson, Rebecca Newlin; Shin, Sonya

    2014-01-01

    Background American Indians and Alaska Native (AI/AN) populations experience significant health disparities compared to non-Hispanic white populations. Cardiovascular disease and related risk factors are increasingly recognized as growing indicators of global health disparities. However, comparative reports on disparities among this constellation of diseases for AI/AN populations have not been systematically reviewed. Objectives We performed a literature review on the prevalence of diabetes, metabolic syndrome, dyslipidemia, obesity, hypertension, and cardiovascular disease; and associated morbidity and mortality among AI/AN. Data sources A total of 203 articles were reviewed, of which 31 met study criteria for inclusion. Searches were performed on PUBMED, MEDLINE, the CDC MMWR, and the Indian Health Services. Study eligibility criteria Published literature that were published within the last fifteen years and provided direct comparisons between AI/AN to non-AI/AN populations were included. Study appraisal and synthesis methods We abstracted data on study design, data source, AI/AN population, comparison group, and. outcome measures. A descriptive synthesis of primary findings is included. Results Rates of obesity, diabetes, cardiovascular disease, and metabolic syndrome are clearly higher for AI/AN populations. Hypertension and hyperlipidemia differences are more equivocal. Our analysis also revealed that there are likely regional and gender differences in the degree of disparities observed. Limitations Studies using BRFSS telephone surveys administered in English may underestimate disparities. Many AI/AN do not have telephones and/or speak English. Regional variability makes national surveys difficult to interpret. Finally, studies using self-reported data may not be accurate. Conclusions and implications of key findings Profound health disparities in cardiovascular diseases and associated risk factors for AI/AN populations persist, perhaps due to low

  10. Cell-matrix interactions of Entamoeba histolytica and E. dispar. A comparative study by electron-, atomic force- and confocal microscopy

    SciTech Connect

    Talamás-Lara, Daniel; Talamás-Rohana, Patricia; Fragoso-Soriano, Rogelio Jaime; Espinosa-Cantellano, Martha; Chávez-Munguía, Bibiana; González-Robles, Arturo; Martínez-Palomo, Adolfo

    2015-10-01

    Invasion of tissues by Entamoeba histolytica is a multistep process that initiates with the adhesion of the parasite to target tissues. The recognition of the non-invasive Entamoeba dispar as a distinct, but closely related protozoan species raised the question as to whether the lack of its pathogenic potential could be related to a weaker adhesion due to limited cytoskeleton restructuring capacity. We here compared the adhesion process of both amebas to fibronectin through scanning, transmission, atomic force, and confocal microscopy. In addition, electrophoretic and western blot assays of actin were also compared. Adhesion of E. histolytica to fibronectin involves a dramatic reorganization of the actin network that results in a tighter contact to and the subsequent focal degradation of the fibronectin matrix. In contrast, E. dispar showed no regions of focal adhesion, the cytoskeleton was poorly reorganized and there was little fibronectin degradation. In addition, atomic force microscopy using topographic, error signal and phase modes revealed clear-cut differences at the site of contact of both amebas with the substrate. In spite of the morphological and genetic similarities between E. histolytica and E. dispar the present results demonstrate striking differences in their respective cell-to-matrix adhesion processes, which may be of relevance for understanding the invasive character of E. histolytica. - Highlights: • Striking differences in adhesion to FN between E. histolytica and E. dispar. • A greater degree of cell stiffness in E. histolytica with respect to E. dispar. • E. histolytica but not E. dispar forms regions of close contact with FN. • The actin cytoskeleton is involved in the pathogenicity of E. histolytica.

  11. Drivers of soil organic matter vulnerability to climate change, Part II: RothC modelling of carbon dynamics including radiocarbon data

    NASA Astrophysics Data System (ADS)

    Studer, Mirjam S.; Abiven, Samuel; González Domínguez, Beatriz R.; Hagedorn, Frank; Reisser, Moritz; Walthert, Lorenz; Zimmermann, Stephan; Niklaus, Pascal A.

    2016-04-01

    It is still largely unknown what drives the vulnerability of soil organic carbon (SOC) stocks to climate change, i.e. the likelihood of a soil to loose its SOC along with the change in environmental conditions. Our objective is to assess the SOC vulnerability of Swiss forest soils and identify its potential drivers: climate (temperature, soil moisture), soil (clay content, pH) and landscape (slope, aspect) properties. Fifty-four sites were selected for balanced spatial and driver magnitudes distribution. We measured the SOC characteristics (content and radiocarbon) and studied the C decomposition by laboratory soil incubations (details in Part I, abstract by B. González Domínguez). In order to assess the current SOC pool distribution and its radiocarbon signatures, we extended the Rothamsted Carbon (RothC) model with radiocarbon (14C) isotope modelling (RothCiso). The RothC model distinguishes four active SOC pools, decomposable and resistant plant material, microbial biomass and humified organic matter, and an inert SOC pool (Jenkinson 1990). The active pools are decomposed and mineralized to CO2 by first order kinetics. The RothCiso assigns all pools a 14C signature, based on the atmospheric 14C concentrations of the past century (plant C inputs) and their turnover. Currently we constrain the model with 14C signatures measured on the 54 fresh and their corresponding archived bulk soil samples, taken 12-24 years before. We were able to reproduce the measured radiocarbon concentrations of the SOC with the RothCiso and first results indicate, that the assumption of an inert SOC pool, that is radiocarbon dead, is not appropriate. In a second step we will compare the SOC mean residence time assessed by the two methodological approaches - incubation (C efflux based) and modelling (C stock based) - and relate it to the environmental drivers mentioned above. With the combination of the two methodological approaches and 14C analysis we hope to gain more insights into

  12. Racial/Ethnic Disparities in Men's Health: Examining Psychosocial Mechanisms.

    PubMed

    Brown, Tyson H; Hargrove, Taylor W; Griffith, Derek M

    2015-01-01

    This study uses data from the Health and Retirement Study and an approach informed by the Biopsychosocial Model of Racism as a Stressor to examine the extent to which socioeconomic status, stressors, discrimination, and neighborhood conditions are mechanisms underlying racial/ethnic disparities in functional limitations among men. Results reveal that racial/ethnic differences in socioeconomic status, stressors, discrimination, and neighborhood conditions-individually and collectively-account for a substantial proportion of racial/ethnic disparities in functional limitations. Findings suggest that the social determinants of health for men of color need to be more seriously considered in investigations of and efforts to address health disparities. PMID:26291191

  13. Racial and Ethnic Disparities in the Use of Health Services

    PubMed Central

    Ashton, Carol M; Haidet, Paul; Paterniti, Debora A; Collins, Tracie C; Gordon, Howard S; O'Malley, Kimberly; Petersen, Laura A; Sharf, Barbara F; Suarez-Almazor, Maria E; Wray, Nelda P; Street, Richard L

    2003-01-01

    African Americans and Latinos use services that require a doctor's order at lower rates than do whites. Racial bias and patient preferences contribute to disparities, but their effects appear small. Communication during the medical interaction plays a central role in decision making about subsequent interventions and health behaviors. Research has shown that doctors have poorer communication with minority patients than with others, but problems in doctor-patient communication have received little attention as a potential cause, a remediable one, of health disparities. We evaluate the evidence that poor communication is a cause of disparities and propose some remedies drawn from the communication sciences. PMID:12542590

  14. A closer look at the rural-urban health disparities: Insights from four major diseases in the Commonwealth of Virginia.

    PubMed

    Zeng, Di; You, Wen; Mills, Bradford; Alwang, Jeffrey; Royster, Michael; Anson-Dwamena, Rexford

    2015-09-01

    Health disparities are increasingly recorded in literature, but are much less understood in a rural-urban context. This study help bridges this gap through investigation of four major diseases in the Commonwealth of Virginia: cancer, stroke, cardiovascular disease and chronic obstructive pulmonary disease. We utilize a unique inpatient hospital discharge billing dataset, and construct average patient counts at ZIP-code level over 2006-2008 where covariates from alternative sources are merged (806 ZIP-code areas, 190 urban, 616 rural). Count data regressions are first fitted to identify possible regional-level factors that affect disease incidences. A system of equations with rural-urban specification are then estimated via seemingly unrelated regression techniques to account for possible associations among these diseases and correlations of errors, which is followed by disease-specific nonlinear Blinder-Oaxaca decompositions that compare the respective explanatory powers of observed characteristics and unobserved mechanisms. Results suggest that regional-level factors are significantly correlated with health outcomes in both rural and urban areas. The unknown mechanisms behind these linkages are different between rural and urban areas, and explain even larger proportions of the observed disparities. These findings confirm the role of regional-level factors in generating rural-urban health disparities, and call for further investigations of the causal mechanisms of such disparities that remain largely unknown. PMID:26204561

  15. Ocular biometrics by score-level fusion of disparate experts.

    PubMed

    Proença, Hugo

    2014-12-01

    The concept of periocular biometrics emerged to improve the robustness of iris recognition to degraded data. Being a relatively recent topic, most of the periocular recognition algorithms work in a holistic way and apply a feature encoding/matching strategy without considering each biological component in the periocular area. This not only augments the correlation between the components in the resulting biometric signature, but also increases the sensitivity to particular data covariates. The main novelty in this paper is to propose a periocular recognition ensemble made of two disparate components: 1) one expert analyses the iris texture and exhaustively exploits the multispectral information in visible-light data and 2) another expert parameterizes the shape of eyelids and defines a surrounding dimensionless region-of-interest, from where statistics of the eyelids, eyelashes, and skin wrinkles/furrows are encoded. Both experts work on disjoint regions of the periocular area and meet three important properties. First, they produce practically independent responses, which is behind the better performance of the ensemble when compared to the best individual recognizer. Second, they do not share particularly sensitivity to any image covariate, which accounts for augmenting the robustness against degraded data. Finally, it should be stressed that we disregard information in the periocular region that can be easily forged (e.g., shape of eyebrows), which constitutes an active anticounterfeit measure. An empirical evaluation was conducted on two public data sets (FRGC and UBIRIS.v2), and points for consistent improvements in performance of the proposed ensemble over the state-of-the-art periocular recognition algorithms. PMID:25296405

  16. Nutritional disparities among women in urban India.

    PubMed

    Agarwal, Siddharth; Sethi, Vani

    2013-12-01

    The paper presents a wealth quartile analysis of the urban subset of the third round of Demographic Health Survey of India to unmask intra-urban nutrition disparities in women. Maternal thinness and moderate/ severe anaemia among women of the poorest urban quartile was 38.5% and 20% respectively and 1.5-1.8 times higher than the rest of urban population. Receipt of pre- and postnatal nutrition and health education and compliance to iron folic acid tablets during pregnancy was low across all quartiles. One-fourth (24.5%) of households in the lowest urban quartile consumed salt with no iodine content, which was 2.8 times higher than rest of the urban population (8.7%). The study highlights the need to use poor-specific urban data for planning and suggests (i) routine field assessment of maternal nutritional status in outreach programmes, (ii) improving access to food subsidies, subsidized adequately-iodized salt and food supplementation programmes, (iii) identifying alternative iron supplementation methods, and (iv) institutionalizing counselling days. PMID:24592595

  17. Nutritional Disparities among Women in Urban India

    PubMed Central

    Sethi, Vani

    2013-01-01

    The paper presents a wealth quartile analysis of the urban subset of the third round of Demographic Health Survey of India to unmask intra-urban nutrition disparities in women. Maternal thinness and moderate/severe anaemia among women of the poorest urban quartile was 38.5% and 20% respectively and 1.5-1.8 times higher than the rest of urban population. Receipt of pre- and postnatal nutrition and health education and compliance to iron folic acid tablets during pregnancy was low across all quartiles. One-fourth (24.5%) of households in the lowest urban quartile consumed salt with no iodine content, which was 2.8 times higher than rest of the urban population (8.7%). The study highlights the need to use poor-specific urban data for planning and suggests (i) routine field assessment of maternal nutritional status in outreach programmes, (ii) improving access to food subsidies, subsidized adequately-iodized salt and food supplementation programmes, (iii) identifying alternative iron supplementation methods, and (iv) institutionalizing counselling days. PMID:24592595

  18. Disparity and convergence in bipedal archosaur locomotion

    PubMed Central

    Bates, K. T.; Schachner, E. R.

    2012-01-01

    This study aims to investigate functional disparity in the locomotor apparatus of bipedal archosaurs. We use reconstructions of hindlimb myology of extant and extinct archosaurs to generate musculoskeletal biomechanical models to test hypothesized convergence between bipedal crocodile-line archosaurs and dinosaurs. Quantitative comparison of muscle leverage supports the inference that bipedal crocodile-line archosaurs and non-avian theropods had highly convergent hindlimb myology, suggesting similar muscular mechanics and neuromuscular control of locomotion. While these groups independently evolved similar musculoskeletal solutions to the challenges of parasagittally erect bipedalism, differences also clearly exist, particularly the distinct hip and crurotarsal ankle morphology characteristic of many pseudosuchian archosaurs. Furthermore, comparative analyses of muscle design in extant archosaurs reveal that muscular parameters such as size and architecture are more highly adapted or optimized for habitual locomotion than moment arms. The importance of these aspects of muscle design, which are not directly retrievable from fossils, warns against over-extrapolating the functional significance of anatomical convergences. Nevertheless, links identified between posture, muscle moments and neural control in archosaur locomotion suggest that functional interpretations of osteological changes in limb anatomy traditionally linked to postural evolution in Late Triassic archosaurs could be constrained through musculoskeletal modelling. PMID:22112652

  19. Environmental exposures, socioeconomics, disparities, and the kidneys.

    PubMed

    Said, Sarmad; Hernandez, German T

    2015-01-01

    Kidney disease disproportionately affects racial and ethnic minority populations, the poor, and the socially disadvantaged. The excess risk of kidney disease among minority and disadvantaged populations can only be partially explained by an excess of diabetes, hypertension, and poor access to preventive care. Disparities in the environmental exposure to nephrotoxicants have been documented in minority and disadvantaged populations and may explain some of the excess risk of kidney disease. High-level environmental and occupational exposure to lead, cadmium, and mercury are known to cause specific nephropathies. However, there is growing evidence that low-level exposures to heavy metals may contribute to the development of CKD and its progression. In this article, we summarize the excess risk of environmental exposures among minority and disadvantaged populations. We also review the epidemiologic and clinical data linking low-level environmental exposure to lead, cadmium, and mercury to CKD and its progression. Finally, we briefly describe Mesoamerican nephropathy, an epidemic of CKD affecting young men in Central America, which may have occupational and environmental exposures contributing to its development. PMID:25573511

  20. Racial Disparities in Early Criminal Justice Involvement

    PubMed Central

    Crutchfield, Robert D.; Skinner, Martie L.; Haggerty, Kevin P.; McGlynn, Anne; Catalano, Richard F.

    2010-01-01

    Criminologists have long reported the existence of racial disparity in the criminal justice system, but the important question is why. While some argue that observed differences are a consequence of more criminal behavior among minorities, the weight of the evidence indicates that this is but a partial explanation. In this paper we study data from a sample of juveniles to examine how racial differences in early police contact, and important social environments—family, school, and neighborhoods—affect later contact and arrests, controlling for self-reported delinquency. We find that early (in middle school) contact with police is an important predictor of later (high school) arrests. Also we found that, in addition to being male and living in a low-income family, children who have parents who have a history of arrest, who have experienced school disciplinary actions, who have delinquent peers, and who are in networks with deviant adults are more likely to have problems with law enforcement. These factors help to explain racial differences in police contacts and arrests. PMID:20190860

  1. Prehistoric demographic fluctuations in China inferred from radiocarbon data and their linkage with climate change over the past 50,000 years

    NASA Astrophysics Data System (ADS)

    Wang, Can; Lu, Houyuan; Zhang, Jianping; Gu, Zhaoyan; He, Keyang

    2014-08-01

    Historic human-climate interactions have been of interest to scholars for a long time. However, exploring the long-term relation between prehistoric demography and climate change remains challenging because of the absence of an effective proxy for population reconstruction. Recently, the summed probability distribution of archaeological radiocarbon dates has been widely used as a proxy for human population levels, although researchers recognize that such usage must be cautious. This approach is rarely applied in China due to the lack of a comprehensive archaeological radiocarbon database, and thus the relation between human population and climate change in China remains ambiguous. Herein we systematically compile an archaeological 14C database (n = 4656) for China for the first time. Using the summed probability distributions of the radiocarbon dates alongside high-resolution palaeoclimatic records, we show that: 1) the commencement of major population expansion in China was at 9 ka cal BP, occurring after the appearance of agriculture and associated with the early Holocene climate amelioration; 2) the major periods of small population size and population decline, i.e., 46-43 ka cal BP, 41-38 ka cal BP, 31-28.6 ka cal BP, 25-23.5 ka cal BP, 18-15.2 ka cal BP, and 13-11.4 ka cal BP, correspond well with the dating of abrupt cold events in the Last Glacial (LG) such as the Heinrich and Younger Dryas (YD) events, while the major periods of high-level population in the Holocene, i.e., 8.5-7 ka cal BP, 6.5-5 ka cal BP and 4.3-2.8 ka cal BP, occur at the same times as warm-moist conditions and Neolithic cultural prosperity, suggesting that abrupt cooling in the climate profoundly limited population size and that mild climate episodes spurred a growth in prehistoric populations and advances in human cultures; and 3) populations in different regions experience different growth trajectories and that their responses to climate change are varied, due to both regional

  2. Reducing Cancer Health Disparities in the US-associated Pacific

    PubMed Central

    Tsark, JoAnn U.; Braun, Kathryn L.

    2010-01-01

    Purpose To assess cancer prevention and control capacity in the US-associated Pacific Islands (USAPI, including American Samoa, Northern Mariana Islands, Micronesia, Guam, Marshall Islands, and Palau) and to support indigenous leadership in reducing cancer health disparities. Methods Jurisdiction-specific needs assessments were conducted to assess cancer prevention and control capacity and challenges, The Cancer Council of the Pacific islands (CCPI), an indigenous health leadership team from public health and medicine, was supported to review assessment findings, develop priorities, and build capacity to address recommendations. Results Capacity varied across jurisdictions, but generally there is limited ability to measure cancer burden and a lack of programs, equipment, and trained personnel to detect and treat cancer. Most cancers are diagnosed in late stages when survival is compromised and care is most costly. Jurisdictions also are challenged by geographic, social, and political constraints and multiple in-country demands for funding. Based on findings, strategies were developed by the CCPI to guide efforts, including fund seeking, to expand cancer prevention and control capacity in regionally appropriate ways. Conclusions Concerted planning, training, and funding efforts are needed to overcome challenges and upgrade capacity in cancer education, prevention, detection, and treatment in the USAPI. Indigenous leadership and local capacity building are essential to this process. PMID:17149100

  3. Radiocarbon based source apportionment of black carbon in the form of PM10 elemental carbon aerosol particles at the Zeppelin Observatory, Svalbard

    NASA Astrophysics Data System (ADS)

    Winiger, Patrik; Andersson, August; Espen Yttri, Karl; Tunved, Peter; Gustafsson, Örjan

    2015-04-01

    Black carbon (BC) aerosol particles are formed from incomplete combustion of fossil fuel and biomass. Transported into the Arctic, they potentially contributes to climate warming. However, there are still large uncertainties related to the climate effects of BC, including aspects of radiative properties, mixing state of the particles, transport, atmospheric lifetime and sources. The current study aims to reduce source uncertainties by applying a top-down (observational) source-diagnostic isotope approach and comparing these to bottom-up (modeling) emission inventories to better constrain the source types and source regions. The use of natural abundance radiocarbon (Δ14C) is a powerful tool to distinguish between fossil (void of 14C) and biomass (contemporary 14C) combustion sources. Due to the well-defined end-members, 14C-measurements (alone) provide high precision (

  4. Disparities in Healthcare for Racial, Ethnic, and Sexual Minorities

    ERIC Educational Resources Information Center

    Collins, Joshua C.; Rocco, Tonette S.

    2014-01-01

    This chapter situates healthcare as a concern for the field of adult education through a critique of disparities in access to healthcare, quality of care received, and caregiver services for racial, ethnic, and sexual minorities.

  5. Asthma and Health Disparities | NIH MedlinePlus the Magazine

    MedlinePlus

    ... page please turn Javascript on. Feature: Breathing Easier Asthma and Health Disparities Past Issues / Fall 2013 Table ... under 18 years of age, who currently have asthma, 2010 Non-Hispanic Black Non-Hispanic White Non- ...

  6. What Are Disparities? | NIH MedlinePlus the Magazine

    MedlinePlus

    ... Immigrant status Disability Sex or gender Sexual orientation Geography Income To better understand the context of disparities, ... while roughly 233.5 million people lived in urban areas (77 percent). An estimated four percent of ...

  7. Robust disparity estimation based on color monogenic curvature phase.

    PubMed

    Zang, Di; Li, Jie; Zhang, Dongdong; Zhang, Junqi

    2012-07-01

    Disparity estimation for binocular images is an important problem for many visual tasks such as 3D environment reconstruction, digital hologram, virtual reality, robot navigation, etc. Conventional approaches are based on brightness constancy assumption to establish spatial correspondences between a pair of images. However, in the presence of large illumination variation and serious noisy contamination, conventional approaches fail to generate accurate disparity maps. To have robust disparity estimation in these situations, we first propose a model - color monogenic curvature phase to describe local features of color images by embedding the monogenic curvature signal into the quaternion representation. Then a multiscale framework to estimate disparities is proposed by coupling the advantages of the color monogenic curvature phase and mutual information. Both indoor and outdoor images with large brightness variation are used in the experiments, and the results demonstrate that our approach can achieve a good performance even in the conditions of large illumination change and serious noisy contamination. PMID:22772192

  8. Disparities in HIV/AIDS, Viral Hepatitis, STDs, and TB

    MedlinePlus

    ... Submit Search The CDC Health Disparities in HIV/AIDS, Viral Hepatitis, STDs, and TB Note: Javascript is ... Hawaiians/Other Pacific Islanders MMWR Publications HIV and AIDS Viral Hepatitis STDs Tuberculosis Training and Networking Resources ...

  9. Development of a dynamic model to guide health disparities research.

    PubMed

    Rew, Lynn; Hoke, Mary M; Horner, Sharon D; Walker, Lorraine

    2009-01-01

    Various populations experience health disparities related to risk factors such as gender, race or ethnicity, educational level, income level, and geographic location. These populations often experience barriers to access and utilization of services, which can lead to adverse health outcomes. Health promotion interventions developed within the context of communities represent resources that may offer protection to these populations. The purpose of this article is to describe the evolution of a conceptual model for the study of health disparities. The model, based on a review of literature, was developed to guide 19 pilot studies funded by the Texas-New Mexico P20 Southwest Partnership Center for Nursing Research on Health Disparities. Reflection on these studies, their respective methodologies, and findings resulted in a revised model to guide further studies of communities experiencing health disparities. PMID:19447233

  10. Disparities in Health Care Quality among Minority Women

    MedlinePlus

    ... 3-EF Go to Online Store Disparities in Health Care Quality Among Minority Women Selected Findings From the ... race and ethnicity are combined. Return to Contents Health Care Delivery and Systems Information about health care delivery ...

  11. Finding Synergy: Reducing Disparities in Health by Modifying Multiple Determinants

    PubMed Central

    Olden, Kenneth

    2010-01-01

    Although researchers acknowledge that health disparities have multiple determinants, most recommendations for reducing inequities focus on a single approach. We suggest integrating 2 approaches for reducing disparities: improving access to primary care and updating and more vigorously enforcing consumer and environmental protection laws. This strategy could reduce the main causes of disparities, such as chronic diseases and injuries; win public and policymaker support; and provide a cost-effective start for achieving equity. Most of the scientific knowledge needed to implement this strategy exists, thus years of additional research would not be needed. Developing targeted regulatory and health care policies to reduce deaths from chronic diseases and injuries would be a major step forward in eliminating health disparities in the United States. PMID:20147690

  12. Racial/Ethnic disparities in depression and its theoretical perspectives.

    PubMed

    Kim, Minjeong

    2014-03-01

    The purpose of this review is to look at racial/ethnic disparities in the diagnosis of depression and its treatment and to explain the dynamics and causes of these racial/ethnic disparities in depression by looking at several theories, such as perceived racism, cultural competency, and other theories. Perceived racism is that the perceptions of an environmental stimulus as being racist affects the coping responses of ethnic/racial minorities, which alters psychological and physiological stress responses, and finally affects health outcomes negatively. A lower level of cultural competence can lead to health disparities. In addition, lower socioeconomic status and health care providers' beliefs and behaviors about patients' race/ethnicity and class can affect depressive symptoms as well as diagnosis and treatment. In order to reduce these racial/ethnic disparities in depression, diverse interventions should be developed to improve depression outcomes for ethnic minority populations based on these theoretical perspectives. PMID:23801269

  13. Radiocarbon-based assessments of the role of fungal species in decomposition

    NASA Astrophysics Data System (ADS)

    Treseder, K. K.; Lansing, J. L.; Choi, N.

    2004-12-01

    We used natural radiocarbon signatures to determine if species of decomposer fungi specialize on different pools of organic matter in the soil. Specifically, we examined natural radiocarbon signatures of mushrooms to estimate the average integrated age of C compounds metabolized by individual species. This method takes advantage of rapid changes in atmospheric radiocarbon signatures of carbon dioxide since the early 1960s, when several years of above-ground weapons testing produced a spike in atmospheric Δ 14C. This signature has been rapidly declining since then. Therefore, we can measure radiocarbon signatures of tissues and determine the time at which their component C was originally photosynthesized. We conducted our study in a fire chronosequence in boreal forests near Delta Junction, Alaska. The chronosequence includes sites burned in severe fires during the summers of 1999, 1987, and 1956. A "control" site was established in a neighboring 80 yr old black spruce forest. In 2002, we collected mushrooms each week from six 50 m long transects in each site. Mushrooms were weighed and assigned to species based on morphological and molecular analyses (i.e. typing by restriction fragment length polymorphism). Saprotrophic species could be distinguished from ectomycorrhizal species based on 15N and 13C signatures. Specifically, saprotrophic mushrooms had δ 15N values less than 4.66\\permil and δ 13C values greater than -23.1\\permil. We then measured the Δ 14C values of mushrooms from 20 of the most abundant saprotrophic species. Radiocarbon signatures varied widely among species, implying that species take up C from compounds that range in turnover time. For example, fungi of the Polyporaceae often grow on woody debris in our sites, and their Δ 14C signatures (-65.1 to 15.0\\permil) indicate the use of several decades-old, recalcitrant C. These fungi are known to possess the necessary enzymes for lignin degradation, so lignocellulose is a likely C source. In

  14. State of the Art of the all-Optical Radiocarbon Detection (Invited)

    NASA Astrophysics Data System (ADS)

    Cancio Pastor, P.; Mazzotti, D.; Galli, I.; Giusfredi, G.; Bartalini, S.; Cappelli, F.; De Natale, P.

    2013-12-01

    Radiocarbon (14C), the 'natural clock' for dating organic matter, is a very elusive atom. Its present concentration is about one part per trillion. For the past 30 years, accelerator mass spectrometry (AMS) has been adopted as the standard method for detecting such carbon isotope at concentrations well below its natural abundance (3 parts per quadrillion). AMS requires a smaller carbon mass and shorter measurement times than the old standard method of liquid scintillation counting. However, AMS requires huge, expensive and high-maintenance experimental facilities. We have developed a laser spectroscopy technique that is sensitive enough to detect the radiocarbon dioxide molecules at very low concentrations with an all-optical setup that is orders of magnitude more compact and less expensive than AMS [1]. The optical spectroscopy approach is based in the detection of very weak absorption of IR laser light by a 14C-containing molecule as 14C-Carbon Dioxide. Spectroscopic techniques as Cavity Ring Down (CRD) spectroscopy that uses the kilometric absorption paths provided by high-Finesse Fabry-Perot cavities have revolutionized the trace gas detection of molecular species in terms of ultimate sensitivity. Nevertheless CRD has been not capable to detect very elusive molecules as radiocarbon Dioxide. The new developed technique, named SCAR (saturated-absorption cavity ring-down), makes use of molecular absorption saturation to enhance resolution and sensitivity with respect to conventional CRD [2]. By combining SCAR with a frequency-comb-linked CW coherent source, which delivers tunable radiation (around 4.5-μm wavelength) [3], we could set an unprecedented limit in trace gas detection, accessing the part-per-quadrillion concentration range. Comparison between AMS and SCAR techniques to detect 14C by measuring the same carbon samples shows SCAR-based results are currently one order of magnitude shy of challenging AMS, but there is still room for improvement [4

  15. Thirteenth radioactive conference, radiocarbon measurements and applications, Dubrovnik, Yugoslavia, June 20--25, 1988: Foreign trip report

    SciTech Connect

    Peng, T.H.

    1988-07-08

    The International Radiocarbon Conference is held once every three years. The purpose of the meeting is to offer an opportunity for an international community of scientists to present and discuss results of their research on improving techniques for radiocarbon measurement and their application in various aspects of natural systems, including the ocean-atmosphere carbon cycle. Four major sessions were held for the presentation of scientific results, another session dealt with radiocarbon data bases, and the final session was devoted to workshops for radiocarbon measurement and international comparison. A total of 152 papers were presented, which included both oral and poster presentations. Participants came from over 30 countries, with a total number of about 200. The paper presented by the traveler, entitled ''Changes in Ocean Ventilation Rates Over the Last 7000 Years Based on /sup 14/C Variations in the Atmosphere and Oceans,'' was included in the oceanography portion of the Carbon Cycle in the Environment session. Radiocarbon is the most powerful and useful tracer for studying the carbon cycle in the atmosphere-biosphere-ocean system. The measuring technique has mostly shifted from a conventional ..beta..-counting approach that uses gas or liquid scintillation counters to an atom counting approach that uses the accelerator mass spectrometer.

  16. Preventing and Removing Contamination in a Natural Radiocarbon Sample Preparation Laboratory

    SciTech Connect

    Zermeno, P; Kurdyla, D K; Buchholz, B A; Heller, S J; Frantz, B R; Brown, T A; Kashgarian, M

    2002-10-25

    The introduction of elevated {sup 14}C contamination into a natural radiocarbon sample preparation laboratory can occur through many different pathways. The most difficult to control is the introduction of contaminated samples from outside labs. Laboratories can remain {sup 14}C contaminated as a result of earlier tracer based research, even if ''hot'' work has not occurred in the laboratories in decades. Prior to accepting samples from outside collaborators, it is recommended that the collaborators test their labs for {sup 14}C contamination. Any surface in a lab that has high use by multiple people has the potential to be contaminated. The standard procedure for determining whether a collaborator's lab is contaminated consists of swiping lab surfaces with small glass fiber filters wetted with alcohol and measuring them for {sup 14}C content using AMS. Volatile {sup 14}C can be detected by using aerosol monitors consisting of fine soot that is depleted in {sup 14}C. These monitors can be set out in the laboratory in question to check for volatile {sup 14}C contamination. In the event that a hot sample is introduced in the natural radiocarbon sample prep laboratory, all sample submission should be stopped until the lab is declared clean. Samples already being processed should be completed along with {sup 14}C depleted material and measured by AMS. This will help determine if the contaminated samples have affected other samples in the laboratory. After a contamination event, the laboratory and associated equipment requires cleaning or disposal. All surfaces and equipment should be wiped down with acetone or ethanol. All chemicals in use should be disposed of in the appropriate waste containers and those waste containers removed from the lab. Once the natural radiocarbon laboratory has been thoroughly ''cleaned'', several background samples consisting of {sup 14}C depleted material should be processed through the lab and measured by AMS before unknown samples are

  17. Further improvement for 10Be measurement on an upgraded compact AMS radiocarbon facility

    NASA Astrophysics Data System (ADS)

    Fu, Dongpo; Ding, Xingfang; Liu, Kexin; Müller, Arnold Milenko; Suter, Martin; Christl, Marcus; Zhou, Liping; Synal, Hans-Arno

    2015-10-01

    The Peking University 500 kV NEC compact AMS radiocarbon facility (PKU-CAMS) has been modified in order to have additionally the possibility to measure 10Be. In the preliminary experiment a silicon nitride foil was mounted in front of the electrostatic deflector as passive boron degrader, and the original Si detector for radiocarbon detection was replaced by an ETHZ-designed high-resolution ΔE - Eres gas ionization chamber (GIC) for 10Be identification. This simple arrangement has yielded an overall 10Be transmission of 2.2% and a 10Be/9Be background level of 3.5 × 10-14. To further reduce the background and increase the transmission by re-focusing the 10Be ions, an additional 90° bending magnet with 350 mm radius was installed after the electrostatic deflector. The silicon detector was shifted slightly relative to its position of original NEC system setup in opposite direction of beam and can be lifted up manually without breaking vacuum when 10Be measurements are carried out. In this way the system can be easily and fast set up for 10Be without affecting any parameters for radiocarbon measurement. The gas detector for 10Be was mounted at the end of the beam line after the additional magnet. The lay-out of the upgraded spectrometer is very compact and does not require more space than the original instrument. Using this compact setup, the overall transmission for 10Be was doubled to 5-6% and the 10Be/9Be background level was reduced to radios as low as 2.4 × 10-15.

  18. AMS radiocarbon dating of mortar: The case study of the medieval UNESCO site of Modena

    NASA Astrophysics Data System (ADS)

    Carmine, Lubritto; Caroselli, Marta; Lugli, Stefano; Marzaioli, Fabio; Nonni, Sara; Marchetti Dori, S.; Terrasi, Filippo

    2015-10-01

    The carbon dioxide contributing to binder formation during the set of a lime mortar reflects the atmospheric 14C content at the time of construction of a building. For this reason, the 14C dating of mortars is used with increasing frequencies in archaeological and architectural research. Mortars, however, may also contain carbonaceous contaminants potentially affecting radiocarbon dating. The Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE) of the Second University of Naples (SUN) has recently obtained some promising results in mortar radiocarbon dating thanks to the development of a procedure (i.e. CryoSoniC/Cryo2SoniC) aiming to eliminate exogenous C contamination that may occur in a mortar. The construction history of the UNESCO World Heritage Site of Modena (Italy) is still controversial and represents a challenging case study for the application of absolute dating methodologies for different reasons. From the point of view of 14C dating, for example, given the high percentage of carbonate aggregates composing these samples, Modena mortars represent an experimental test particularly indicative of exogenous carbon sources suppression ensuring methodology accuracy. In this paper several AMS Radiocarbon dates were carried out on lime lumps with the aim to: (i) verify procedure accuracy by a comparison of the results obtainable from lime lumps dated after different treatments (i.e. bulk lime lumps vs. CryoSoniC purified lime lumps); (ii) compare different building phases absolute chronology for the medieval UNESCO site of Modena, with that assumed by historical sources in order to assess preliminary the 14C dating feasibility for of the site. Historical temporal constraints and mortar clustering, based on petrography, have been applied to define a temporal framework of the analyzed structure. Moreover, a detailed petrographic characterization of mortars was used both as a preliminary tool for the choice of samples and to infer about the

  19. North Atlantic surface ocean radiocarbon reservoir age variation: links to rapid global climate change

    NASA Astrophysics Data System (ADS)

    Austin, W. E. N.; Brown, L.; Telford, R. J.; Ninnemann, U. S.; Wilson, L. J.; Bryant, C. L.

    2009-04-01

    High resolution palaeoclimate records show that the overall warming throughout the late glacial period to the present has been punctuated by repeated cooling events on decadal to centennial timescales. Reorganisation of the North Atlantic's deep water thermohaline circulation is often considered an important factor in triggering or controlling these abrupt climate change intervals. During the Younger Dryas (YD), the most significant of these late glacial climatic coolings, a large, positive anomaly in atmospheric radiocarbon concentration (Δ14Catm) is observed, which is not fully accounted for by changes in the production rate of 14C. Another potential source of Δ14Catm variation is the extent of carbon exchange between the atmosphere and other reservoirs, such as the deep ocean, and it has been suggested that the circulation changes which drove the YD cooling were also partially responsible for limiting air-sea CO2 exchange and hence increasing Δ14Catm. Reconstructions of North Atlantic surface ocean radiocarbon reservoir ages (Rt) during the Younger Dryas, based on known-age markers such as tephra horizons, demonstrate an increase in Rt from modern values of 400 y to >800 y, widely believed to be indicative of reduced carbon exchange between the atmosphere and the deep ocean. However, the limited temporal resolution of these measurements has thus far been insufficient to fully explore the connection between changing Rt and rapid, ocean circulation-induced climate change. Here we present a detailed reconstruction of changing Rt in the late glacial period, from a high resolution marine sediment record north of 50° N. Stable isotope records and radiocarbon chronologies from cores collected in the St Kilda Basin, Hebridean shelf, containing highly-expanded late glacial records, will be used to assess the importance and controlling mechanisms of reservoir age variation in the NE Atlantic.

  20. Comparison of Radiocarbon Ages for Multiproxy Paleoclimate Reconstruction of the Great Salt Lake, Utah

    NASA Astrophysics Data System (ADS)

    Nielson, K. E.; Bowen, G. J.; Eglinton, T. I.

    2008-12-01

    Multiproxy paleoclimate reconstructions from high sedimentation-rate systems offer promising opportunities to deconvolve multiple aspects climate system response to past forcing. However, the time-equivalence of proxies must be established before such reconstructions can be usefully interpreted. Differences in source ages, transport pathways, and surface residence times for substrates may lead to differences in lag times between proxy formation and deposition, compromising comparative analysis of data from multiple proxies. We used multi-substrate radiocarbon dating to investigate the potential for multi-proxy reconstruction of Holocene changes in the volume of the Great Salt Lake (GSL), Utah, based on the stable isotope composition of organic and inorganic substrates in lake sediment cores. Among potential substrates for this work are normal alkanes of vascular higher plant and algal origin, fossil cysts of lake-dwelling brine shrimp (Artemia), and micritic aragonite. Radiocarbon ages for all organic substrates (alkanes, cysts) sampled at any given core depth are concordant within analytical uncertainty and are similar to ages determined on land-plant debris and filamentous algae isolated from the sediment. Inorganic carbonate, in contrast, is depleted in 14C compare to the organic proxies, giving ages that were apparently 2000 to 3000 years older, likely due to winnowing and re-deposition of carbonate at the core site. These results suggest that the maximum temporal resolution achievable through analysis of mineral substrates is on the order of several millennia. Although the limited precision of the radiocarbon analysis precludes precise determination of the maximum potential resolution of organic-proxy based climate reconstructions, the relatively high sedimentation rates (50--150 cm/kyr) and age-equivalence of the substrates analyzed implies that sub- centennial scale resolution should be achievable throughout much of the Holocene portion of the GSL