1,648 research outputs found

    An Index to Assess the Sensitivity of Gulf of Mexico Species to Changes in Estuarine Salinity Regimes

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    An index of biological sensitivity to changes in freshwater inflow was developed for 44 species in 22 Gulf of Mexico estuaries for adult and juvenile life stages of fishes and macroinvertebrates. The BioSalinity Index (BSI) provides an innovative approach to quantify estuary-specific sensitivity of organisms to changes in estuarine salinity regimes based upon our knowledge of species salinity habitat preferences, the availability of this preferred habitat, and the relative abundance and distribution of species in time and space. We found that a significant difference exists between adult and juvenile life stage sensitivity, with juveniles exhibiting a lower sensitivity to salinity changes than adults, and that a considerable disparity exists in species-specific sensitivities among Gulf estuaries. Likewise, when the full complement of 44 species-level BSIs are averaged, marked differences in assemblage-wide sensitivity are evident across estuaries. The availability of preferred salinity habitat had a greater influence on the BSI for estuarine species than did their relative abundance and temporal distribution. The BSI was applied by members of a 1995 Gulf of Mexico freshwater inflow workshop to identify a subset of estuaries which appear more sensitive to freshwater inflow changes and are candidates for further study

    MANURE MANAGEMENT FOR WATER QUALITY COSTS TO ANIMAL FEEDING OPERATIONS OF APPLYING MANURE NUTRIENTS TO LAND

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    Nutrients from livestock and poultry manure are key sources of water pollution. Ever-growing numbers of animals per farm and per acre have increased the risk of water pollution. New Clean Water Act regulations compel the largest confined animal producers to meet nutrient application standards when applying manure to the land, and USDA encourages all animal feeding operations to do the same. The additional costs for managing manure (such as hauling manure off the farm) have implications for feedgrain producers and consumers as well. This report's farm-level analysis examines on-farm technical choice and producer costs across major U.S. production areas for hauling manure to the minimum amount of land needed to assimilate manure nutrients. A regional analysis then focuses on off-farm competition for land to spread surplus manure, using the Chesapeake Bay region as a case study. Finally, a sectorwide analysis addresses potential long-term structural adjustments at the national level and ultimate costs to consumers and producers.manure management costs, price and quantity adjustments, water quality, animal waste, manure nutrients, excess nutrients, confined animals, CAFO, manure nitrogen, manure phosphorus, manure use, assimilative capacity, nutrient management plan, Environmental Economics and Policy, Livestock Production/Industries,

    The Mission Accessible Near-Earth Objects Survey: Four years of photometry

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    Over 4.5 years, the Mission Accessible Near-Earth Object Survey (MANOS) assembled 228 Near-Earth Object (NEO) lightcurves. We report rotational lightcurves for 82 NEOs, constraints on amplitudes and periods for 21 NEOs, lightcurves with no detected variability within the image signal to noise and length of our observing block for 30 NEOs, and 10 tumblers. We uncovered 2 ultra-rapid rotators with periods below 20s; 2016MA with a potential rotational periodicity of 18.4s, and 2017QG18_{18} rotating in 11.9s, and estimate the fraction of fast/ultra-rapid rotators undetected in our project plus the percentage of NEOs with a moderate/long periodicity undetectable during our typical observing blocks. We summarize the findings of a simple model of synthetic NEOs to infer the object morphologies distribution using the measured distribution of lightcurve amplitudes. This model suggests a uniform distribution of axis ratio can reproduce the observed sample. This suggests that the quantity of spherical NEOs (e.g., Bennu) is almost equivalent to the quantity of highly elongated objects (e.g., Itokawa), a result that can be directly tested thanks to shape models from Doppler delay radar imaging analysis. Finally, we fully characterized 2 NEOs as appropriate targets for a potential robotic/human mission: 2013YS2_{2} and 2014FA7_{7} due to their moderate spin periods and low Δv\Delta v.Comment: Accepted for Publication, The Astrophysical Journal Supplement Serie

    A habitat-use model to determine essential fish habitat for juvenile brown shrimp (Farfantepenaeus aztecus) in Galveston Bay, Texas

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    A density prediction model for juvenile brown shrimp (Farfantepenaeus aztecus) was developed by using three bottom types, five salinity zones, and four seasons to quantify patterns of habitat use in Galveston Bay, Texas. Sixteen years of quantitative density data were used. Bottom types were vegetated marsh edge, submerged aquatic vegetation, and shallow nonvegetated bottom. Multiple regression was used to develop density estimates, and the resultant formula was then coupled with a geographical information system (GIS) to provide a spatial mosaic (map) of predicted habitat use. Results indicated that juvenile brown shrimp (0.50. These results indicate that this model may have a broader geographic application and is a plausible approach in refining current EFH designations for all Gulf of Mexico estuaries with similar geomorphological and hydrological characteristics

    Toll-like Receptor 7 and TLR9 Dictate Autoantibody Specificity and Have Opposing Inflammatory and Regulatory Roles in a Murine Model of Lupus

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    SummaryAntibodies (Abs) to RNA- and DNA-containing autoantigens are characteristic of systemic lupus erythematosus (SLE). We showed previously that Toll-like receptor (TLR) 9, recognizing DNA, is required for the spontaneous generation of DNA autoantibodies, but not for the development of lupus nephritis in susceptible mice. We report that lupus-prone mice deficient in TLR7, a receptor for ssRNA, failed to generate Abs to RNA-containing antigens (Ags) such as Smith (Sm) Ag. TLR9 and TLR7 also had dramatic effects on clinical disease in lupus-prone mice. In the absence of TLR9, autoimmune disease was exacerbated, lymphocytes and plasmacytoid DCs were more activated, and serum IgG and IFN-α were increased. In contrast, TLR7-deficient mice had ameliorated disease, decreased lymphocyte activation, and decreased serum IgG. These findings reveal opposing inflammatory and regulatory roles for TLR7 and TLR9, despite similar tissue expression and signaling pathways. These results have important implications for TLR-directed therapy of autoimmune disease

    Kepler Input Catalog: Photometric Calibration and Stellar Classification

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    We describe the photometric calibration and stellar classification methods used to produce the Kepler Input Catalog (KIC). The KIC is a catalog containing photometric and physical data for sources in the Kepler Mission field of view; it is used by the mission to select optimal targets. We derived atmospheric extinction corrections from hourly observations of secondary standard fields within the Kepler field of view. Repeatability of absolute photometry for stars brighter than magnitude 15 is typically 2%. We estimated stellar parameters Teff, log(g), log (Z), E_{B-V} using Bayesian posterior probability maximization to match observed colors to Castelli stellar atmosphere models. We applied Bayesian priors describing the distribution of solar-neighborhood stars in the color-magnitude diagram (CMD), in log (Z)$, and in height above the galactic plane. Comparisons with samples of stars classified by other means indicate that in most regions of the CMD, our classifications are reliable within about +/- 200 K and +/- 0.4 dex in log (g). It is difficult to assess the reliability of our log(Z) estimates, but there is reason to suspect that it is poor, particularly at extreme Teff. Of great importance for the Kepler Mission, for Teff <= 5400 K, the distinction between main-sequence stars and giants has proved to be reliable with better than 98% confidence. The KIC is available through the MAST data archive.Comment: 77 pages, 12 figures, 1 Table. Accepted by Astronomical Journal 24 July 201

    Modelling ultrasound-induced mild hyperthermia of hyperplasia in vascular grafts

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    <p>Abstract</p> <p>Background</p> <p>Expanded polytetrafluoroethylene (ePTFE) vascular grafts frequently develop occlusive neointimal hyperplasia as a result of myofibroblast over-growth, leading to graft failure. ePTFE exhibits higher ultrasound attenuation than native soft tissues. We modelled the selective absorption of ultrasound by ePTFE, and explored the feasibility of preventing hyperplasia in ePTFE grafts by ultrasound heating. Specifically, we simulated the temperature profiles of implanted grafts and nearby soft tissues and blood under ultrasound exposure. The goal was to determine whether ultrasound exposure of an ePTFE graft can generate temperatures sufficient to prevent cell growth on the graft without damaging nearby soft tissues and blood.</p> <p>Methods</p> <p>Ultrasound beams from two transducers (1.5 and 3.2 MHz) were simulated in two graft/tissue models, with and without an intra-graft cellular layer mimicking hyperplasia, using the finite-difference time-domain (FDTD) method. The resulting power deposition patterns were used as a heat source for the Pennes bioheat equation in a COMSOL<sup>® </sup>Multiphysics heat transfer model. 50°C is known to cause cell death and therefore the transducer powers were adjusted to produce a 13°C temperature rise from 37°C in the ePTFE.</p> <p>Results</p> <p>Simulations showed that both the frequency of the transducers and the presence of hyperplasia significantly affect the power deposition patterns and subsequent temperature profiles on the grafts and nearby tissues. While neither transducer significantly raised the temperature of the blood, the 1.5-MHz transducer was less focused and heated larger volumes of the graft and nearby soft tissues than the 3.2-MHz transducer. The presence of hyperplasia had little effect on the blood's temperature, but further increased the temperature of the graft and nearby soft tissues in response to either transducer. Skin cooling and blood flow play a significant role in preventing overheating of the native tissues.</p> <p>Conclusions</p> <p>Modelling shows that ultrasound can selectively heat ePTFE grafts and produce temperatures that cause cell death on the graft. The temperature increase in blood is negligible and that in the adjacent soft tissues may be minimized by skin cooling and using appropriate transducers. Therefore, ultrasound heating may have the potential to reduce neointimal hyperplasia and failure of ePTFE vascular grafts.</p

    Toll-like receptor 9 controls anti-DNA autoantibody production in murine lupus

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    Systemic autoimmune disease in humans and mice is characterized by loss of immunologic tolerance to a restricted set of self-nuclear antigens. Autoantigens, such as double-stranded (ds) DNA and the RNA-containing Smith antigen (Sm), may be selectively targeted in systemic lupus erythematosus because of their ability to activate a putative common receptor. Toll-like receptor 9 (TLR9), a receptor for CpG DNA, has been implicated in the activation of autoreactive B cells in vitro, but its role in promoting autoantibody production and disease in vivo has not been determined. We show that in TLR9-deficient lupus-prone mice, the generation of anti-dsDNA and antichromatin autoantibodies is specifically inhibited. Other autoantibodies, such as anti-Sm, are maintained and even increased in TLR9-deficient mice. In contrast, ablation of TLR3, a receptor for dsRNA, did not inhibit the formation of autoantibodies to either RNA- or DNA-containing antigens. Surprisingly, we found that despite the lack of anti-dsDNA autoantibodies in TLR9-deficient mice, there was no effect on the development of clinical autoimmune disease or nephritis. These results demonstrate a specific requirement for TLR9 in autoantibody formation in vivo and indicate a critical role for innate immune activation in autoimmunity

    The effects of preeclampsia on signaling to hematopoietic progenitor cells

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    Background: The role of the microenvironment is important in cell differentiation. The effect of placental disease on the growth and differentiation and hematopoietic stem cells has not been well-studied. Methods: Enzyme linked immunoassay was used to measure erythropoietin and osteopontin in plasma from umbilical cord blood of children born to normotensive and preeclamptic women. Additionally, CD34+ cells were isolated from umbilical cord blood and grown in complete methylcellulose media. Colony types were identified and enumerated. Results: Differences in the concentration of erythropoietin in the cord blood between the controls and the preeclamptics approached significance (P = 0.067) using a Mann-Whitney U test. In the plasma of cord blood from children born to normotensive women, the median erythropoietin was 0.186 mIU/mL compared to 1.986 mIU/mL in children of preeclamptic women. We did not find any significant differences in the number and types of colonies; however, there was a trend toward increased BFU-E in the preeclamptic samples. Furthermore, this trend for increased BFU-E colonies was also seen from CD34+ cells isolated from umbilical cord blood of severe preeclamptics compared to mild. Conclusion: Our preliminary studies suggest that abnormalities in the placenta, such as those found when the mother experiences preeclampsia, may affect the ability of hematopoietic stem cells to grow and differentiate

    A Characterization of the Shallow-Water Coral Reefs and Associated Habitats of Puerto Rico

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    We mapped bottom types and shelf zones of 1600 km2 or about one fourth of Puerto Rico’s insular shelf from the shoreline to the shelf edge. Overall map accuracy for these bottom types is estimated as 93.6% correct. Maps were produced through visual interpretation of benthic features using orthorectified aerial photographs within a Geographic Information System with customizable software. The maps are one component of an integrated mapping and monitoring program underway by NOAA and its partners in the US Coral Reef Task Force to assess all US reef ecosystems. Maps are currently being used to enhance coastal research and management activities in Puerto Rico such as fisheries assessments and designation of important fish habitats
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