829 research outputs found

    Assessing movements of three buoy line types using DSTmilli Loggers: Implications for entanglements of bottlenose dolphins in the crab pot fishery

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    A study was conducted in October 2006 in the Charleston, South Carolina area to test the movements of three different buoy line types to determine which produced a preferred profile that could reduce the risk of dolphin entanglement. Tests on diamond-braided nylon commonly used in the crab pot fishery were compared with stiffened line of Esterpro and calf types in both shallow and deep water environments using DSTmilli data loggers. Loggers were placed at intervals along the lines to record depth, and thus movements, over a 24 hour period. Three observers viewed video animations and charts created for each of the six trial days from the collected logger data and provided their opinions on the most desirable line type that fit set criteria. A quantitative analysis (ANCOVA) of the data was conducted taking into consideration daily tidal fluctuations and logger movements. Loggers tracking the tides had an r2 value approaching 1.00 and produced little movement other than with the tides. Conversely, r2 values approaching 0.00 were less affected by tidal movement and influenced by currents that cause more erratic movement. Results from this study showed that stiffened line, in particular the medium lay Esterpro type, produced the more desirable profiles that could reduce risk of dolphin entanglement. Combining the observer’s results with the ANCOVA results, Esterpro was chosen nearly 60% of the time as opposed to the nylon line which was only chosen 10% of the time. ANCOVA results showed that the stiffened lines performed better in both the shallow and deep water environments, while the nylon line only performed better during one trial in a deep water set, most probably due to the increased current velocities experienced that day. (58pp.)(PDF contains 68 pages

    Plantas novas mineiras.

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    "Spicilegium pteridologicum austro-brasiliense, par H. Christ": p. [11]-42, fasc. 2.Photocopy (positive)Fasc. 2 has imprint: Cidade de Minas, Impr. official de Estado de Minas Geraes.At head of title: Estado de Minas Geraes.Mode of access: Internet

    Where were they from? Modelling the source stock of dolphins stranded after the Deepwater Horizon oil spill using genetic and stable isotope data

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    Understanding the source stock of common bottlenose dolphins Tursiops truncatus that stranded in the northern Gulf of Mexico subsequent to the Deepwater Horizon oil spill was essential to accurately quantify injury and apportion individuals to the appropriate stock. The aim of this study, part of the Natural Resource Damage Assessment (NRDA), was to estimate the proportion of the 932 recorded strandings between May 2010 and June 2014 that came from coastal versus bay, sound and estuary (BSE) stocks. Four sources of relevant information were available on overlapping subsets totaling 336 (39%) of the strandings: genetic stock assignment, stable isotope ratios, photo-ID and individual genetic-ID. We developed a hierarchical Bayesian model for combining these sources that weighted each data source for each stranding according to a measure of estimated precision: the effective sample size (ESS). The photo- and genetic-ID data were limited and considered to potentially introduce biases, so these data sources were excluded from analyses used in the NRDA. Estimates were calculated separately in 3 regions: East (of the Mississippi outflow), West (of the Mississippi outflow through Vermilion Bay, Louisiana) and Western Louisiana (west of Vermilion Bay to the Texas-Louisiana border); the estimated proportions of coastal strandings were, respectively 0.215 (95% CI: 0.169-0.263), 0.016 (0.036-0.099) and 0.622 (0.487-0.803). This method represents a general approach for integrating multiple sources of information that have differing uncertainties.Publisher PDFPeer reviewe

    The Deepwater Horizon oil spill marine mammal injury assessment

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    The studies described here were conducted as part of the DWH NRDA and included scientists funded through NOAA, other federal and state Trustees, and BP PLC. The John H. Prescott Marine Mammal Rescue Assistance Grant Program and the Marine Mammal Health and Stranding Response Program provided funding for this work in addition to the funding from the DWH NRDA.From 2010 to 2015, a team of scientists studied how the BP Deepwater Horizon (DWH) oil spill affected marine mammals inhabiting the northern Gulf of Mexico, as part of the DWH Natural Resource Damage Assessment process. The scientists conducted the assessment on behalf of the DWH co-Trustees, with the purpose of investigating whether marine mammals were exposed to DWH oil and what types of injuries they suffered as a result of the DWH oil exposure, and then quantifying those injuries to determine the appropriate amount of restoration required to offset the injuries. Photographs, aerial surveys, spatial analyses of the co-occurrence between surface slick and cetacean populations, and chemical fingerprinting of oiled and stranded carcasses all confirm that at least 15 cetacean species were exposed to the DWH surface slick. Cetaceans that encountered the slick likely inhaled, aspirated, ingested, and/or adsorbed oil. In this Theme Section, marine mammal biologists, statisticians, veterinarians, toxicologists, and epidemiologists describe and quantify the adverse effects of this oil exposure. Taken together, this combination of oil spill dynamics, veterinary assessments, pathological, spatial, and temporal analyses of stranded animals, stock identification techniques, population dynamics, and a broad set of coordinated modeling efforts is an unprecedented assessment of how a major oil spill impacted a large and complex marine mammal community and their connected habitats.Publisher PDFPeer reviewe

    Quantifying injury to common bottlenose dolphins from the Deepwater Horizon oil spill using an age-, sex- and class-structured population model

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    Field studies documented increased mortality, adverse health effects, and reproductive failure in common bottlenose dolphins Tursiops truncatus following the Deepwater Horizon (DWH) oil spill. In order to determine the appropriate type and amount of restoration needed to compensate for losses, the overall extent of injuries to dolphins had to be quantified. Simply counting dead individuals does not consider long-term impacts to populations, such as the loss of future reproductive potential from mortality of females, or the chronic health effects that continue to compromise survival long after acute effects subside. Therefore, we constructed a sex- and agestructured model of population growth and included additional class structure to represent dolphins exposed and unexposed to DWH oil. The model was applied for multiple stocks to predict injured population trajectories using estimates of post-spill survival and reproductive rates. Injured trajectories were compared to baseline trajectories that were expected had the DWH incident not occurred. Two principal measures of injury were computed: (1) lost cetacean years (LCY); the difference between baseline and injured population size, summed over the modeled time period, and (2) time to recovery; the number of years for the stock to recover to within 95% of baseline. For the dolphin stock in Barataria Bay, Louisiana, the estimated LCY was substantial: 30 347 LCY (95% CI: 11 511 to 89 746). Estimated time to recovery was 39 yr (95% CI: 24 to 80). Similar recovery timelines were predicted for stocks in the Mississippi River Delta, Mississippi Sound, Mobile Bay and the Northern Coastal Stock.Publisher PDFPeer reviewe

    Two-step OFFGEL approach for effective peptide separation compatible with iTRAQ labeling

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    Shotgun proteomic analyses are increasingly becoming methods of choice for complex samples. The development of effective methods for fractionating peptides to reduce the complexity of the sample before mass analysis is a key point in this strategy. The OFFGEL technology has recently become a tool of choice in proteomic analysis at peptide level. This OFFGEL electrophoresis (OGE) approach allows the in-solution separation of peptides from various biological sources by isoelectric focusing in highly resolved 24 fractions. It was also demonstrated that OGE technology is a filtering tool for pI-based validation of peptide identification. As peptide OGE is compatible with iTRAQ labeling, OGE is finding valuable applications in quantitative proteomics as well. The aim of this study is to explain a new 2D-OGE approach that improves the proteomic coverage of complex mixtures such as colorectal cell line lysates, and which is compatible with iTRAQ labeling

    Mechanical Properties and Characterization of Nanocrystalline Ni and Ni Solid Solutions

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    In this work we investigate the mechanical properties of nanocrystalline Ni and Ni solid solutions made by both traditional fabrication methods (through a literature review) and by a newly developed chemical-derivation method (through experimental characterization and nanoindentaiton testing). Chapter 1 consists of a review of the current literature on nanocrystalline Ni. It focuses specifically on how the grain size of these materials is related to hardness through the Hall-Petch relationship and at grain sizes past the Hall-Petch breakdown. Given the number of apparent deviations from the Hall-Petch relationship found in the literature, in Chapter 2 we consider factors other than grain size which can impact hardness, including additives, annealing, and texture. Chapter 3 provides a description of our own experimental methods and results, including sample fabrication, grain size measurement, and nanoindentation. The hardness and reduced modulus of our nanocrystalline Ni samples are calculated to be 56 MPa and 1.76 GPa, respectively. These values are very low compared to what is described in the literature. Chapter 4 presents models for the hardness and Young’s modulus of nanocrystalline materials as functions of porosity, impurity content, and other factors which might cause anomalously low values. However, we find that these models are unable to account for the values we have observed. Chapter 5 includes a discussion of future work which should be done in order to better understand the deformation occurring in chemically-derived nanocrystalline Ni and how it differs from what is described in the literature

    Selected reactive oxygen species and antioxidant enzymes in common bean after Pseudomonas syringae pv. phaseolicola and Botrytis cinerea infection

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    Phaseolus vulgaris cv. Korona plants were inoculated with the bacteria Pseudomonas syringae pv. phaseolicola (Psp), necrotrophic fungus Botrytis cinerea (Bc) or with both pathogens sequentially. The aim of the experiment was to determine how plants cope with multiple infection with pathogens having different attack strategy. Possible suppression of the non-specific infection with the necrotrophic fungus Bc by earlier Psp inoculation was examined. Concentration of reactive oxygen species (ROS), such as superoxide anion (O2 -) and H2O2 and activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were determined 6, 12, 24 and 48 h after inoculation. The measurements were done for ROS cytosolic fraction and enzymatic cytosolic or apoplastic fraction. Infection with Psp caused significant increase in ROS levels since the beginning of experiment. Activity of the apoplastic enzymes also increased remarkably at the beginning of experiment in contrast to the cytosolic ones. Cytosolic SOD and guaiacol peroxidase (GPOD) activities achieved the maximum values 48 h after treatment. Additional forms of the examined enzymes after specific Psp infection were identified; however, they were not present after single Bc inoculation. Subsequent Bc infection resulted only in changes of H2O2 and SOD that occurred to be especially important during plant–pathogen interaction. Cultivar Korona of common bean is considered to be resistant to Psp and mobilises its system upon infection with these bacteria. We put forward a hypothesis that the extent of defence reaction was so great that subsequent infection did not trigger significant additional response

    Survival, density, and abundance of common bottlenose dolphins in Barataria Bay (USA) following the Deepwater Horizon oil spill

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    To assess potential impacts of the Deepwater Horizon oil spill in April 2010, we conducted boat-based photo-identification surveys for common bottlenose dolphins Tursiops truncatus in Barataria Bay, Louisiana, USA (~230 km2, located 167 km WNW of the spill center). Crews logged 838 h of survey effort along pre-defined routes on 10 occasions between late June 2010 and early May 2014. We applied a previously unpublished spatial version of the robust design capture-recapture model to estimate survival and density. This model used photo locations to estimate density in the absence of study area boundaries and to separate mortality from permanent emigration. To estimate abundance, we applied density estimates to saltwater (salinity > ~8 ppt) areas of the bay where telemetry data suggested that dolphins reside. Annual dolphin survival varied between 0.80 and 0.85 (95% CIs varied from 0.77 to 0.90) over 3 yr following the Deepwater Horizon spill. In 2 non-oiled bays (in Florida and North Carolina), historic survival averages approximately 0.95. From June to November 2010, abundance increased from 1300 (95% CI ± ~130) to 3100 (95% CI ± ~400), then declined and remained between ~1600 and ~2400 individuals until spring 2013. In fall 2013 and spring 2014, abundance increased again to approximately 3100 individuals. Dolphin abundance prior to the spill was unknown, but we hypothesize that some dolphins moved out of the sampled area, probably northward into marshes, prior to initiation of our surveys in late June 2010, and later immigrated back into the sampled area.Publisher PDFPeer reviewe
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