60 research outputs found

    Late Pleistocene to Mid-Holocene climate variability in Ireland : evidence from Ostracod geochemistry

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    Stable isotope values of ostracod calcite provide a record of variation in „À18O(H2O) values and water temperature from the late glacial to mid-Holocene in Western Ireland. Lough Monreagh, located in County Clare, Western Ireland, contains marl sediment that includes pristine ostracod calcite whose „À18O and „À13C values were evaluated. These values were used relative to modern ecological requirements to derive a paleoenvironmental record for Lough Monreagh that includes water temperature, eutrophication, water depth, as well as terrestrial vegetation and weathering within the lakeÂĄÂŻs watershed. „À13C values of ostracod calcite presented herein suggest a significant increase in terrestrial vegetation beginning during the Aller©ÂȘd (13,600 cal year B.P.) and extending through to the mid-Holocene (6,997 cal year B.P.). Marl and ostracod „À18O values record variability in temperature and precipitation „À18O(H2O) values that are in turn forced by variation in atmospheric and oceanic circulation. Water temperatures presented herein were calculated from „À18O values of ostracod calcite and marl, constrained by temperature preference and tolerance ranges of ostracod species, yielding the highest resolution temperature record covering this period to date. Over 4,700 ostracods representing all three freshwater superfamilies were counted and identified to evaluate the trophic stage of the lake. The lake was characterized as a clear-, cold-water (~8šC summer water temperature), low-nutrient environment during the Aller©ÂȘd, then freezes abruptly during the Younger Dryas as evidenced by black clay deposits aged 12,800 to 11,300 cal yr B.P. Following the Younger Dryas, transitional warming and increasing terrestrial vegetation are evidenced by decreasing „À13C values of ostracoda and faunal transition to phytophyllic species. Summer water temperatures warm to >16šC, with ostracod species suggesting a shallow-water, fen- and macrophyte-rich environment with abundant plant life in and around the lake by ~8,000 cal yr B.P

    Late Holocene Sedimentation and Paleoenvironmental History for the Tidal Marshes of the Potomac and Rappahannock Rivers, Tributaries to Chesapeake Bay

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    Instrumental tide gauge records indicate that the modern rates of sea-level rise in the Chesapeake Bay more than double the global average of 1.2-1.5 mm yr-1. The primary objective for this study is to establish a relative depositional history for the tidal marshes of the Potomac and Rappahannock Rivers that will help us improve our understanding of processes that influence sedimentation in the proximal tributaries of Chesapeake Bay. Marsh cores were collected from Blandfield Point VA, Tappahannock VA, and Potomac Creek VA. The sedimentary facies include: 1) a lower unit of organic-poor, grey clay with fine sand and silt layers and estuarine foraminifera; and 2) an upper unit of organic-rich clay and peat with abundant brackish to freshwater marsh foraminifera and thecamoebians. AMS 14C dating of bulk marsh sediments yield sedimentation rates at Potomac Creek ranging from 3.04-4.20 mm yr-1 for the past 2500 years. Rates of sedimentation calculated for Blandfield Point indicate 1.37-2.19 mm yr-1 in the basal clays and peat for the past ~3000 years. Foraminiferal census counts indicate a freshening upward trend with a transition from an estuarine Ammobaculites crassus assemblage to a marsh Ammoastuta salsa assemblage with abundant freshwater thecamoebians. The late Holocene history of sedimentation for the marshes indicates that differential compaction, recent land use practices, and climate change have contributed to the resultant freshening-upward environmental trend and variability in sediment accumulation rates between coring sites

    Tax Policy Forum: Review of Tax Expenditures, Budget 2016

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    In the 2016 budget the Department of Finance announced that it intended to review a number of tax expenditures with the objective of identifying and eliminating poorly targeted or inefficient tax measures. In this article, the authors discuss the concept and theory of tax expenditures and then debate the merits of some of the more significant tax expenditures with the objective of identifying those that might be considered poorly targeted or inefficient

    Airborne cow allergen, ammonia and particulate matter at homes vary with distance to industrial scale dairy operations: an exposure assessment

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    <p>Abstract</p> <p>Background</p> <p>Community exposures to environmental contaminants from industrial scale dairy operations are poorly understood. The purpose of this study was to evaluate the impact of dairy operations on nearby communities by assessing airborne contaminants (particulate matter, ammonia, and cow allergen, Bos d 2) associated with dairy operations inside and outside homes.</p> <p>Methods</p> <p>The study was conducted in 40 homes in the Yakima Valley, Washington State where over 61 dairies operate.</p> <p>Results</p> <p>A concentration gradient was observed showing that airborne contaminants are significantly greater at homes within one-quarter mile (0.4 km) of dairy facilities, outdoor Bos d 2, ammonia, and TD were 60, eight, and two times higher as compared to homes greater than three miles (4.8 km) away. In addition median indoor airborne Bos d 2 and ammonia concentrations were approximately 10 and two times higher in homes within one-quarter mile (0.4 km) compared to homes greater than three miles (4.8 km) away.</p> <p>Conclusions</p> <p>These findings demonstrate that dairy operations increase community exposures to agents with known human health effects. This study also provides evidence that airborne biological contaminants (i.e. cow allergen) associated with airborne particulate matter are statistically elevated at distances up to three miles (4.8 km) from dairy operations.</p

    What Do We Feed to Food-Production Animals? A Review of Animal Feed Ingredients and Their Potential Impacts on Human Health

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    OBJECTIVE: Animal feeding practices in the United States have changed considerably over the past century. As large-scale, concentrated production methods have become the predominant model for animal husbandry, animal feeds have been modified to include ingredients ranging from rendered animals and animal waste to antibiotics and organoarsenicals. In this article we review current U.S. animal feeding practices and etiologic agents that have been detected in animal feed. Evidence that current feeding practices may lead to adverse human health impacts is also evaluated. DATA SOURCES: We reviewed published veterinary and human-health literature regarding animal feeding practices, etiologic agents present in feed, and human health effects along with proceedings from animal feed workshops. DATA EXTRACTION: Data were extracted from peer-reviewed articles and books identified using PubMed, Agricola, U.S. Department of Agriculture, Food and Drug Administration, and Centers for Disease Control and Prevention databases. DATA SYNTHESIS: Findings emphasize that current animal feeding practices can result in the presence of bacteria, antibiotic-resistant bacteria, prions, arsenicals, and dioxins in feed and animal-based food products. Despite a range of potential human health impacts that could ensue, there are significant data gaps that prevent comprehensive assessments of human health risks associated with animal feed. Limited data are collected at the federal or state level concerning the amounts of specific ingredients used in animal feed, and there are insufficient surveillance systems to monitor etiologic agents “from farm to fork.” CONCLUSIONS: Increased funding for integrated veterinary and human health surveillance systems and increased collaboration among feed professionals, animal producers, and veterinary and public health officials is necessary to effectively address these issues

    Toward Human-Carnivore Coexistence: Understanding Tolerance for Tigers in Bangladesh

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    Fostering local community tolerance for endangered carnivores, such as tigers (Panthera tigris), is a core component of many conservation strategies. Identification of antecedents of tolerance will facilitate the development of effective tolerance-building conservation action and secure local community support for, and involvement in, conservation initiatives. We use a stated preference approach for measuring tolerance, based on the ‘Wildlife Stakeholder Acceptance Capacity’ concept, to explore villagers’ tolerance levels for tigers in the Bangladesh Sundarbans, an area where, at the time of the research, human-tiger conflict was severe. We apply structural equation modeling to test an a priori defined theoretical model of tolerance and identify the experiential and psychological basis of tolerance in this community. Our results indicate that beliefs about tigers and about the perceived current tiger population trend are predictors of tolerance for tigers. Positive beliefs about tigers and a belief that the tiger population is not currently increasing are both associated with greater stated tolerance for the species. Contrary to commonly-held notions, negative experiences with tigers do not directly affect tolerance levels; instead, their effect is mediated by villagers’ beliefs about tigers and risk perceptions concerning human-tiger conflict incidents. These findings highlight a need to explore and understand the socio-psychological factors that encourage tolerance towards endangered species. Our research also demonstrates the applicability of this approach to tolerance research to a wide range of socio-economic and cultural contexts and reveals its capacity to enhance carnivore conservation efforts worldwide

    Decoupling genetics, lineages, and microenvironment in IDH-mutant gliomas by single-cell RNA-seq

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    Tumor subclasses differ according to the genotypes and phenotypes of malignant cells as well as the composition of the tumor microenvironment (TME).We dissected these influences in isocitrate dehydrogenase (IDH)-mutant gliomas by combining 14,226 single-cell RNA sequencing (RNA-seq) profiles from 16 patient samples with bulk RNA-seq profiles from 165 patient samples. Differences in bulk profiles between IDH-mutant astrocytoma and oligodendroglioma can be primarily explained by distinct TME and signature genetic events, whereas both tumor types share similar developmental hierarchies and lineages of glial differentiation. As tumor grade increases, we find enhanced proliferation of malignant cells, larger pools of undifferentiated glioma cells, and an increase in macrophage over microglia expression programs in TME. Our work provides a unifying model for IDH-mutant gliomas and a general framework for dissecting the differences among human tumor subclasses.National Cancer Institute (U.S.) (Grant P30-CA14051

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure
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