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81.
Coastal habitats near urban centres in North Atlantic estuaries often support substantial numbers of wintering waterfowl, but little is known of the effects of landscape setting and urbanisation on habitat use. We conducted surveys of waterfowl at 32 wintering sites in Narragansett Bay, Rhode Island, to identify characteristics that may influence habitat use. Sites were chosen along a gradient of urbanisation and reflected the dominant habitat types used by waterfowl in the Bay. Mean waterfowl abundance was 206.7 ± 209.5 birds per site, and sites in the inner part of the estuary had higher overall waterfowl abundances (r2 = 0.40, p = 0.021). Species richness ranged from 3.2 to 13.0 and decreased with increasing hunting activity (r2 = 0.36, p = 0.040). Hunting activity and habitat characteristics (e.g., latitude, shoreline configuration, prey density) explained 13-27% of the variation in waterfowl abundance and species richness among sites, but landscape characteristics (e.g., surrounding residential development, vegetated land, or wetland surrounding the sites and the extent of wetland edge) explained an additional 1-26%. The landscape characteristics extent of adjacent residential development and vegetated upland were the most common variables entering into the models; most species were more abundant at sites with more adjacent vegetated upland and less adjacent residential development. Our results suggest that landscape setting may be influencing the distribution of wintering waterfowl, and should be considered when developing strategies for the conservation for these species in urban North Atlantic estuaries.  相似文献   
82.
There has been interest within the pesticide regulatory community in developing a tool that can provide estimates of potential pesticide exposure in shallow groundwater across an intended use area. Therefore, industry initiated an investigative project based on the PRZM 3.12 model, which uses regional soils and weather in an easy to use interface. The goal of this proof-of-concept is to facilitate the refinement of groundwater exposure estimates. The focus of this paper is to report the effectiveness of the tool as a regional estimator of potential groundwater contamination.  相似文献   
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Analysis of the spatial distribution of all species of conservation importance within a region is necessary to augment reserve selection strategies and habitat management in biodiversity conservation. In this study, we analyzed the spatial aggregation, spatial association, and vegetation types of point occurrence data collected from museum and herbaria records for rare, special concern, threatened, and endangered species of plants, reptiles, mammals, and birds in western Riverside County in southern California, USA. All taxa showed clumped distributions, with aggregation evident below 14 km for plants, 12 km for reptiles, 2 km for mammals, and 10 km for birds. In addition, all combinations of the different species groups showed high positive spatial association. The Santa Rosa Plateau exhibited the highest number of rare, special concern, threatened, and endangered species, and shrubland (coastal sage and chaparral) was the vegetation type inhabited by the most species. Local land use planning, zoning and reserve design should consider the spatial aggregation within and between species to determine the appropriate scale for conservation planning. The higher spatial association between species groups in this study may indicate interdependence between different species groups or shared habitat requirements. It is important to maintain diverse communities due to potential interdependence. The results of the study indicate that concentrating preservation efforts on areas with the highest number of species of concern and the restoration of native shrublands are the most appropriate actions for multiple species habitat conservation in this area.  相似文献   
86.
Bran extracts of Akron wheat grown at four nonirrigated and one irrigated testing locations were examined and compared for their free radical scavenging properties against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(*)) and the radical cation ABTS(*)(+), chelating capacities, and total phenolic content (TPC) to determine the potential effects of environmental factors on the antioxidant properties of hard winter wheat. The environmental factors included total solar radiation, average daily solar radiation, and number of hours exceeding 32 degrees C. The results showed that bran samples from different growing locations may significantly differ in their radical scavenging activities against both DPPH(*) and ABTS(*)(+), chelating capacities, and TPC. A significant negative correlation was detected between the chelating activities of the bran samples from the four nonirrigated locations and total solar or daily average solar radiation (r = -0.999 and P = 0.001). These data suggest potential influences of growing conditions on the antioxidant properties of hard winter wheat and the possibility of producing wheat that is strong in a selected antioxidant property by optimizing the growing conditions of a selected wheat variety. More research is required to further investigate the relationship among antioxidant properties and environmental factors using different wheat varieties and larger sample sizes.  相似文献   
87.
The aim of the current research was to investigate the possible occurrence of a single nucleotide polymorphism (SNP) in exon 2 of the equine leptin gene in obese mares determined to be hyperleptinemic. Three experiments were conducted: one to determine the prevalence of hyperleptinemic horses in the resident herd; another to complete the sequencing of exon 2 and flanking introns of the equine leptin gene, which had been partially sequenced by others; and a third to compare the exon 2 sequences of obese, hyperleptinemic mares with those of obese mares not displaying hyperleptinemia. In experiment 1, jugular blood was collected from 31 mares, and they were categorized by age, body condition score (BCS), and average plasma leptin concentrations. Mean BCS was correlated (P < .001) with leptin concentrations; age was not. Five obese, hyperleptinemic and five obese, nonhyperleptinemic mares were selected to study the possibility of polymorphism in exon 2. First, in experiment 2, forward and reverse primers were designed from the Bos taurus leptin gene (GenBank Accession # U50365) to identify and subsequently clone the equine leptin gene to provide material for sequencing. The multiple copies of genomic DNA were then used for sequencing of exon 2 and the flanking introns. Comparative genomics was used to further identify and characterize regulatory elements in the 5' and 3' flanking regions of the leptin gene. In experiment 3, DNA from the five mares of each type (previously selected in experiment 1) was extracted, and exon 2 was sequenced and analyzed for possible SNP. The sequences of exon 2 for the 10 mares were identical; thus, no polymorphism was present. It was concluded that approximately one third of obese, pasture-maintained mares and geldings in the resident herd display hyperleptinemia relative to other horses of similar body condition, but this condition was not associated with the occurrence of SNP in exon 2 of the leptin gene.  相似文献   
88.
The ability of porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae to be transported over long distances via the airborne route was evaluated. A source population of 300 grow-finish pigs was experimentally inoculated with PRRSV MN-184 and M. hyopneumoniae 232 and over a 50-day period, air samples were collected at designated distances from the source herd using a liquid cyclonic collector. Samples were tested for the presence of PRRSV RNA and M. hyopneumoniae DNA by PCR and if positive, further characterized. Of the 306 samples collected, 4 (1.3%) were positive for PRRSV RNA and 6 (1.9%) were positive for M. hyopneumoniae DNA. The PRRSV-positive samples were recovered 4.7 km to the northwest (NW) of the source population. Four of the M. hyopneumoniae-positive samples were obtained at the NW sampling point; 2 samples at approximately 2.3 km and the other 2 samples approximately 4.7 km from the source population. Of the remaining 2 samples, one sample was obtained at the southeast sampling point and the other at the southwest sampling point, with both locations being approximately 4.7 km from the source. The four PRRSV-positive samples contained infectious virus and were ≥ 98.8% homologous to the MN-184 isolate used to inoculate the source population. All 6 of the M. hyopneumoniae-positive samples were 99.9% homologous to M. hyopneumoniae 232. These results support the hypothesis that long distance airborne transport of these important swine pathogens can occur.  相似文献   
89.
A 15 year-old Thoroughbred mare was examined for lethargy, fever, and inappetence of 1-day duration. A hard-bodied tick was removed from the horse. A complete blood count (CBC) demonstrated leukopenia with lymphopenia and thrombocytopenia. Morulae were visualized in circulating granulocytes. A polymerase chain reaction (PCR) confirmed the identity of these organisms as Anaplasma phagocytophilum. The horse was treated symptomatically for fever and inappetence with flunixin meglumine (1.1 mg/kg [0.5 mg/lb]) and oral electrolyte paste. Oxytetracycline (6.6 mg/kg [3 mg/lb] intravenously every 24 hours) treatment was begun as soon as a definitive diagnosis was determined. The mare responded to treatment, but she was switched to oral doxycycline (10 mg/kg [4.5 mg/lb] every 12 hours) after 5 days because of perivascular swelling at the injection site. Complete resolution of clinical signs was seen. There was no evidence of recurrence 1 year later. No additional horses at the farm were affected. The horse in this report presented for lethargy, inappetence, and fever, with limited other abnormalities. This represents a classical presentation of a mild to moderate case of anaplasmosis, which had not previously been reported in Virginia. The disease may be more widespread than has been previously reported, and it should warrant inclusion on a complete differential diagnosis list in a case of fever of unknown origin.  相似文献   
90.
Management practices to prevent or control outbreaks of Streptococcus equi subsp. equi often include consideration of environment survival, but limited objective data are available. This study involved evaluation of S. equi persistence following inoculation of wood, metal, and rubber surfaces in an outdoor environment. Survival was short, ranging from < 1 to 3 d. There was no effect of rain (P = 0.33) or surface type (P = 0.95), but there was an effect of sunlight (P = 0.002). Outdoor survival of S. equi is poor, and prolonged quarantine of outdoor areas, particularly areas exposed to the sun, is probably unnecessary.  相似文献   
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