269 research outputs found

    Lower Permian algal stromatolites from Kansas and Oklahoma

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    20 p., 10 fig.http://paleo.ku.edu/contributions.htm

    Observations of a midlatitude squall line boundary layer wake

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    Includes bibliographical references (pages 90-93).June 1987.Mesoscale pressure perturbations frequently observed with mesoscale convective systems (MCS) are examined with special emphasis on the characteristics, structure, lifecycle and driving mechanism of the "wake depression" found in the wake region of the convection. A severe squall line which traversed the OK PRE-STORM surface and upper air mesonetwork on 10-11 June 1985 is the focus of this observational study. Extensive surface, upper air and digitized radar data collected during the OK PRE-STORM field experiment were used for analysis. Various mesoanalyses of this squall line at the surface and aloft have allowed for intensive examination of three pressure features observed with this squall line: the mesohigh, wake depression and pre-squall mesolow. Their relationship to and interaction with other meteorological parameters such as precipitation, temperature, potential temperature and moisture are explored. Furthermore, the mesoscale system-relative "jets" observed with midlatitude squall lines are examined for their possible influence on the pressure field. The mesohigh develops quickly during the early growth of the squall line and precedes the wake depression by several hours. The predominant mesohigh is linked to the formation of a large cold pool which developed as a result of widespread hail and intense rainfall from a supercell ahead of the young squall line. Analyses show that the wake depression is not a uniform, stagnant feature behind the mesohigh but has embedded small-scale features, a distinct lifecycle and can undergo rapid intensification. The wake depression also is related to some aspects of the squall line's precipitation pattern. The low consistently "hugs" the back edge of the stratiform precipitation and is observed to split into two separate lows as the convective line splits. Additionally, the wake depression is a hydrostatic response to a layer of warm, dry air (produced by subsidence) found just above the surface. It is suggested that the wake depression is in part a surface manifestation of forced subsidence by the descending rear inflow jet.Sponsored by the National Science Foundation - ATM-8507961

    Urban Heat Island and Vulnerable Population. The Case of Madrid

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    The Urban Heat Island effect shows the differences among temperatures in urban areas and the surrounding rural ones. Previous studies have demonstrated that temperature differences could be up to 8 °C during the hottest periods of summer in Madrid , and that it varies according to the urban structure. Associated to this effect, the impact of temperature increase over dwelling indoor thermal comfort seems to double cooling energy demand . In Madrid, fuel poor households already suffering from inadequate indoor temperatures can face important overheating problems and, as a consequence, relevant health problems could become more frequent and stronger. This poses an increment in mortality rates in risk groups that should be evaluated. This research is aimed at establishing the geospatial connection between the urban heat island and the most vulnerable population living in the city of Madrid. Hence, those areas most in need for an urban intervention can be detected and prioritized

    The Floor of Yellowstone Lake is Anything but Quiet—New Discoveries from High-Resolution Sonar Imaging, Seismic- Reflection Profiling, and Submersible Studies

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    Discoveries from multibeam sonar mapping and seis-mic-reflection surveys of Yellowstone Lake provide new insight into the recent geologic forces that have shaped a large lake at the active front of the Yellowstone hot spot, a region strongly affected by young (\u3c2 \u3em.y.), large-volume (\u3e100–1,000s km3) silicic volcanism, active tectonism, and accompanying uplift. Specifically, our mapping has identified the extent of postcaldera-collapse volcanism and active hydrothermal processes occurring above a large magma chamber beneath the lake floor. Multiple advances and recessions of thick glacial ice have overlapped volcanic and hydrothermal activity leaving a lake basin that has been shaped predominantly by fire and ice. Yellowstone Lake has an irregular bottom covered with dozens of features directly related to hydrothermal, tectonic, volcanic,and sedimentary processes. Detailed bathymetric, seismic-reflection, and magnetic evidence reveals that rhyolitic lava flows underlie much of Yellowstone Lake and exert fundamental control on lake morphology and localization of hydrothermal activity in the northern, West Thumb, and central basins. Many previously unknown features have been identified and include more than 660 hydrothermal vents, several very large (\u3e500-m diameter) hydrothermal-explosion craters, many small hydrothermal-vent craters (~1-to 200-m diameter), domed lacustrine sediments related to hydrothermal activity, elongate fissures cutting postglacial sediments, siliceous hydrothermal-spire structures, sublacustrine landslide deposits, submerged former shorelines, large glacial melting features, incipient faulting along the trace of the Eagle Bay fault zone, and a recently active graben. Sampling and observations with a submersible remotely operated vehicle confirm and extend our understanding of the identified features. Faults, fissures, hydrothermally inflated domal structures, hydrothermal-explosion craters, and sublacustrine landslides constitute potentially significant geologic hazards. Toxic elements derived from hydrothermal processes also may significantly affect the Yellowstone ecosystem

    The Floor of Yellowstone Lake is Anything but Quiet—New Discoveries from High-Resolution Sonar Imaging, Seismic- Reflection Profiling, and Submersible Studies

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    Discoveries from multibeam sonar mapping and seis-mic-reflection surveys of Yellowstone Lake provide new insight into the recent geologic forces that have shaped a large lake at the active front of the Yellowstone hot spot, a region strongly affected by young (\u3c2 \u3em.y.), large-volume (\u3e100–1,000s km3) silicic volcanism, active tectonism, and accompanying uplift. Specifically, our mapping has identified the extent of postcaldera-collapse volcanism and active hydrothermal processes occurring above a large magma chamber beneath the lake floor. Multiple advances and recessions of thick glacial ice have overlapped volcanic and hydrothermal activity leaving a lake basin that has been shaped predominantly by fire and ice. Yellowstone Lake has an irregular bottom covered with dozens of features directly related to hydrothermal, tectonic, volcanic,and sedimentary processes. Detailed bathymetric, seismic-reflection, and magnetic evidence reveals that rhyolitic lava flows underlie much of Yellowstone Lake and exert fundamental control on lake morphology and localization of hydrothermal activity in the northern, West Thumb, and central basins. Many previously unknown features have been identified and include more than 660 hydrothermal vents, several very large (\u3e500-m diameter) hydrothermal-explosion craters, many small hydrothermal-vent craters (~1-to 200-m diameter), domed lacustrine sediments related to hydrothermal activity, elongate fissures cutting postglacial sediments, siliceous hydrothermal-spire structures, sublacustrine landslide deposits, submerged former shorelines, large glacial melting features, incipient faulting along the trace of the Eagle Bay fault zone, and a recently active graben. Sampling and observations with a submersible remotely operated vehicle confirm and extend our understanding of the identified features. Faults, fissures, hydrothermally inflated domal structures, hydrothermal-explosion craters, and sublacustrine landslides constitute potentially significant geologic hazards. Toxic elements derived from hydrothermal processes also may significantly affect the Yellowstone ecosystem

    Rheumatoid Factor as a Potentiator of Anti–Citrullinated Protein Antibody–Mediated Inflammation in Rheumatoid Arthritis

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    Objective. The co-occurrence of rheumatoid factor (RF) and anti–citrullinated protein antibody (ACPA) positivity in rheumatoid arthritis (RA) is well described. However, the mechanisms underlying the potential interaction between these 2 distinct autoantibodies have not been well defined. The aim of this study was to evaluate the epidemiologic and molecular interaction of ACPAs and RF and its association with both disease activity and measures of RA-associated inflammation. Methods. In a cohort of 1,488 US veterans with RA, measures of disease activity and serum levels of cytokines and multiplex ACPAs were compared between the following groups of patients: double-negative (anti–cyclic citrullinated peptide [anti-CCP]-/RF-), anti-CCP+/RF-, anti-CCP-/RF+, or double-positive (anti-CCP+/RF+). Additional studies were performed using an in vitro immune complex (IC) stimulation assay in which macrophages were incubated with ACPA ICs in the presence or absence of monoclonal IgM-RF, and tumor necrosis factor α production measured as a readout of macrophage activation. Results. Compared with the double-negative subgroup (as well as each single-positive subgroup), the double-positive subgroup exhibited higher disease activity as well as higher levels of C-reactive protein and inflammatory cytokines (all P \u3c 0.001). In vitro stimulation of macrophages by ACPA ICs increased cytokine production, and the addition of monoclonal IgM-RF significantly increased macrophage tumor necrosis factor α production (P = 0.003 versus ACPA ICs alone). Conclusion. The combined presence of ACPAs and IgM-RF mediates increased proinflammatory cytokine production in vitro and is associated with increased systemic inflammation and disease activity in RA. Our data suggest that IgM-RF enhances the capacity of ACPA ICs to stimulate macrophage cytokine production, thereby providing a mechanistic link by which RF enhances the pathogenicity of ACPA ICs in RA

    Fine-scale spatial variability of heat-related mortality in Philadelphia County, USA, from 1983-2008: a case-series analysis

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    <p>Abstract</p> <p>Background</p> <p>High temperature and humidity conditions are associated with short-term elevations in the mortality rate in many United States cities. Previous research has quantified this relationship in an aggregate manner over large metropolitan areas, but within these areas the response may differ based on local-scale variability in climate, population characteristics, and socio-economic factors.</p> <p>Methods</p> <p>We compared the mortality response for 48 Zip Code Tabulation Areas (ZCTAs) comprising Philadelphia County, PA to determine if certain areas are associated with elevated risk during high heat stress conditions. A randomization test was used to identify mortality exceedances for various apparent temperature thresholds at both the city and local scale. We then sought to identify the environmental, demographic, and social factors associated with high-risk areas via principal components regression.</p> <p>Results</p> <p>Citywide mortality increases by 9.3% on days following those with apparent temperatures over 34°C observed at 7:00 p.m. local time. During these conditions, elevated mortality rates were found for 10 of the 48 ZCTAs concentrated in the west-central portion of the County. Factors related to high heat mortality risk included proximity to locally high surface temperatures, low socioeconomic status, high density residential zoning, and age.</p> <p>Conclusions</p> <p>Within the larger Philadelphia metropolitan area, there exists statistically significant fine-scale spatial variability in the mortality response to high apparent temperatures. Future heat warning systems and mitigation and intervention measures could target these high risk areas to reduce the burden of extreme weather on summertime morbidity and mortality.</p

    Increasing Support for Contraception as HIV Prevention: Stakeholder Mapping to Identify Influential Individuals and Their Perceptions

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    BACKGROUND: Voluntary contraceptive use by HIV-positive women currently prevents more HIV-positive births, at a lower cost, than anti-retroviral drug (ARV) regimens. Despite this evidence, most prevention of mother-to-child transmission (PMTCT) programs focus solely on providing ARV prophylaxis to pregnant women and rarely include the prevention of unintended pregnancies among HIV-positive women. METHODOLOGY/PRINCIPAL FINDINGS: To strengthen support for family planning as HIV prevention, we systematically identified key individuals in the field of international HIV/AIDS-those who could potentially influence the issue-and sought to determine their perceptions of barriers to and facilitators for implementing this PMTCT strategy. We used a criteria-based approach to determine which HIV/AIDS stakeholders have the most significant impact on HIV/AIDS research, programs, funding and policy and stratified purposive sampling to conduct interviews with a subset of these individuals. The interview findings pointed to obstacles to strengthening linkages between family planning and HIV/AIDS, including the need for: resources to integrate family planning and HIV services, infrastructure or capacity to provide integrated services at the facility level, national leadership and coordination, and targeted advocacy to key decision-makers. CONCLUSIONS/SIGNIFICANCE: The individuals we identified as having regional or international influence in the field of HIV/AIDS have the ability to leverage an increasingly conducive funding environment and a growing evidence base to address the policy, programmatic and operational challenges to integrating family planning with HIV/AIDS. Fostering greater support for implementing contraception for HIV prevention will require the dedication, collaboration and coordination of many such actors. Our findings can inform a targeted advocacy campaign

    A sociological dilemma: race, segregation, and US sociology

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    US sociology has been historically segregated in that, at least until the 1960s, there were two distinct institutionally organized traditions of sociological thought – one black and one white. For the most part, however, dominant historiographies have been silent on that segregation and, at best, reproduce it when addressing the US sociological tradition. This is evident in the rarity with which scholars such as WEB Du Bois, E Franklin Frazier, Oliver Cromwell Cox, or other ‘African American Pioneers of Sociology’, as Saint-Arnaud calls them, are presented as core sociological voices within histories of the discipline. This article addresses the absence of African American sociologists from the US sociological canon and, further, discusses the implications of this absence for our understanding of core sociological concepts. With regard to the latter, the article focuses in particular on the debates around equality and emancipation and discusses the ways in which our understanding of these concepts could be extended by taking into account the work of African American sociologists and their different interpretations of core themes
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