A spatial risk assessment of bighorn sheep extirpation by grazing domestic sheep on public lands     

Tim E. Carpenter  Victor L. Coggins  Clinton McCarthy  Chans S. O’Brien  Joshua M. O’Brien  Timothy J. Schommer 《Preventive veterinary medicine》2014

Bighorn sheep currently occupy just 30% of their historic distribution, and persist in populations less than 5% as abundant overall as their early 19th century counterparts. Present-day recovery of bighorn sheep populations is in large part limited by periodic outbreaks of respiratory disease, which can be transmitted to bighorn sheep via contact with domestic sheep grazing in their vicinity. In order to assess the viability of bighorn sheep populations on the Payette National Forest (PNF) under several alternative proposals for domestic sheep grazing, we developed a series of interlinked models. Using telemetry and habitat data, we characterized herd home ranges and foray movements of bighorn sheep from their home ranges. Combining foray model movement estimates with known domestic sheep grazing areas (allotments), a Risk of Contact Model estimated bighorn sheep contact rates with domestic sheep allotments. Finally, we used demographic and epidemiologic data to construct population and disease transmission models (Disease Model), which we used to estimate bighorn sheep persistence under each alternative grazing scenario. Depending on the probability of disease transmission following interspecies contact, extirpation probabilities for the seven bighorn sheep herds examined here ranged from 20% to 100%. The Disease Model allowed us to assess the probabilities that varied domestic sheep management scenarios would support persistent populations of free-ranging bighorn sheep.  相似文献   

Discovery of a new avian bornavirus genotype in estrildid finches (Estrildidae) in Germany     

Dennis Rubbenstroth  Volker Schmidt  Monika Rinder  Marko Legler  Victor Max Corman  Peter Staeheli 《Veterinary microbiology》2014,168(2-4):318-323

Avian bornaviruses (ABV) are known to be the causative agent of proventricular dilatation disease (PDD) in parrots and their relatives (Psittaciformes). A broad range of ABV genotypes has been detected not only in psittacine birds, but also in other avian species including canary birds (Serinus canaria forma domestica) and Bengalese finches (Lonchura striata f. dom.), which are both members of the order songbirds (Passeriformes).During this study 286 samples collected from captive and wild birds of various passerine species in different parts of Germany were screened for the presence of ABV. Interestingly, only three ABV-positive samples were identified by RT-PCR. They originated from one yellow-winged pytilia (Pytilia hypogrammica) and two black-rumped waxbills (Estrilda troglodytes) from a flock of captive estrildid finches in Saxony. The ABV isolates detected here were only distantly related to ABV isolates found in passerine species in Germany and Japan and form a new genotype tentatively called ABV-EF (for “estrildid finches”).  相似文献   

Fishing gear effects and ecology of the sea whip (Halipteris willemoesi (Cnidaria: Octocorallia: Pennatulacea)) in British Columbia,Canada: preliminary observations     

Peter M. Troffe  Colin D. Levings  G. E. Piercey  Victor Keong 《水产资源保护:海洋与淡水生态系统》2005,15(5):523-533

• 1. We conducted a preliminary study of the effects of a shrimp beam trawl and prawn traps on sea whips (Halipteris willemoesi (Cnidaria: Octocorallia: Pennatulacea)) at two bays on Clio Channel, south central coast of British Columbia, Canada. Video and grabs surveys were conducted to estimate abundance and make observations on sea whips and their habitat.
• 2. No adult sea whips were caught in six beam trawls. In 600 prawn (Pandalus platyceros) trap sets at Turnour Bay, 30 sea whips were found entangled in the gear and of these 50% of the colonies were damaged. The length of broken sea whips ranged from 0.09 to 1.03 m. At Turnour Bay, the density of adults observed in video surveys ranged from 7.1 to 14.3 m^?2. Juvenile density in grab samples ranged from 53 to 123 m^?2 and a few adults were also caught. The lengths of intact adult sea whips caught in traps and grabs ranged from 0.20 to 1.98 m and juveniles from 0.3 to 0.7 cm.
• 3. Fewer adult sea whips (<0.1 m^?2) were seen in Bones Bay, where sediments were muddier (grain size <0.25 mm: 84.6 to 97.2%) relative to Turnour Bay (grain size <0.25 mm: 71.4 to 85.9%). Bottom water characteristics at the two bays were similar. Seasonal temperature range was 7.5–8.4°C, salinity 30.63–31.49 psu, and dissolved oxygen 2.76–5.97 mg L^?1. Differences in sediment characteristics and food availability may have been a factor influencing differences in abundance of sea whips between the two bays.
• 4. Further data are needed to investigate the effects of trawling and trapping on sea whips, as sample sizes were small in the present study and only two gear types were evaluated. Studies of effects of otter trawling and heavier traps, such as those used for Dungeness crab (Cancer magister), are warranted.

Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Evaluation of the nitrogen sufficiency index for use with high resolution,broadband aerial imagery in a commercial potato field   总被引：1，自引：0，他引：1  

Tyler J. Nigon  David J. Mulla  Carl J. Rosen  Yafit Cohen  Victor Alchanatis  Ronit Rud 《Precision Agriculture》2014,15(2):202-226

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Primary epitheliotropic intestinal T-cell lymphoma in a horse.     

Marie E Pinkerton  Keith L Bailey  Kathy K Thomas  Thomas E Goetz  Victor E Valli 《Journal of veterinary diagnostic investigation》2002,14(2):150-152

A 17-year-old Quarterhorse gelding with a clinical diagnosis of protein-losing enteropathy was submitted for necropsy following a 4-5-month duration of weight loss, decreased appetite, and hypoproteinemia. Gross findings included multiple 1-2-cm diameter ulcers on the luminal surfaces of the duodenum and ileum. Histologic examination revealed individual large, round cells infiltrating much of the mucosal epithelium of the duodenum, jejunum, ileum, and colon in addition to multifocal areas of ulceration. Similar round cells infiltrated Brunner's glands and expanded the submucosa beneath the foci of ulceration. Immunohistochemical staining indicated the round cell population was of T-lymphocyte origin. Several features of this equine neoplasm bear similarities to enteropathy-associated T-cell lymphoma in humans.  相似文献   

Agronomical performance and breeding value of selected strains of diploid wheat,Triticum monococcum   总被引：1，自引：0，他引：1  

Victor Vallega 《Euphytica》1992,61(1):13-23

Summary Twenty-one germplasm accessions and breeding lines of einkorn wheat (Triticum monococcum ssp. monococcum and ssp. sinskajae) were grown at two sites in Italy and evaluated for various field and seed characteristics. Grain yields of germplasm accessions were relatively high (317–3238 kg/ha), but distinctly lower than those of four modern cultivars of tetraploid (T. turgidum ssp. durum) and hexaploid wheat (T. aestivum ssp. Aestivum) included in the experiments as controls. As expected, all Einkorns-including some substantially higher yielding crossbred lines (3415–4362 kg/ha)-were defective for one or more agronomically relevant features. However, a few of the accessions examined were found to contain, as a group, practically all the genes needed to breed monococcums having the main field attributes of a modern wheat cultivar: high yielding capacity, good threshability, large kernel size, earliness, short stature and adequate lodging resistance. Still higher yielding diploid wheats, more responsive to improved growing conditions and of better seed quality, could probably be obtained from crosses with wild monococcums bearing mostly two-seeded florets and with accessions producing less slender-shaped kernels. Some of the Einkorns examined were found to carry minor genes for easy threshing which might enhance the efficacy of the major gene for soft glumes carried by T. monococcum ssp. sinskajae, a partially free-threshing diploid wheat taxon. Seed protein percentage of monococcums was markedly higher than that of durum and bread wheat cultivars even in those cases where their grain yields surpassed those of the polyploid checks. The possibilities offered by diploid wheat in the exploitation of novel endosperm mutants and F₁ hybrid vigour, as well as in the fields of celiac disease, crop diversification and resistance to agro-biological stresses are discussed. Breeding priorities and strategies are also proposed.  相似文献   

Syntheses of (Z,E)-5,7-dodecadienol and (E,Z)-10,12-hexadecadienol,lepidoptera pheromone components,via zinc reduction of enyne precursors. test of pheromone efficacy against the Siberian moth     

Khrimian A  Klun JA  Hijji Y  Baranchikov YN  Pet'ko VM  Mastro VC  Kramer MH 《Journal of agricultural and food chemistry》2002,50(22):6366-6370

Efficient syntheses of (Z,E)-5,7-dodecadienol, a pheromone component of the Siberian moth, Dendrolimus superans sibiricus, and (E,Z)-10,12-hexadecadienol, a pheromone component of various Lepidoptera pheromones, were accomplished by cis reduction of the corresponding enynols with activated zinc. The most energetic reagent was zinc galvanized with copper and silver (Zn/Cu/Ag) that achieved rapid and high-yield reduction in methanol-water. The stereoselectivity of semi-hydrogenation was > or =98%. A process whereby zinc dust was continuously activated throughout the reduction with an acid was also satisfactory (95-98% cis). Field evaluation of the 1:1 mixture of (Z,E)-5,7-dodecadienol and (Z,E)-5,7-dodecadienal with the Siberian moth in Russia showed that the rubber septa pretreated with compound and stored at -80 degrees C were as effective as freshly treated septa. Moth responses to septa aged in open air indicated that lure effectiveness declined significantly after 2 weeks of aging. Thus, if rubber septa are used as pheromone dispensers in Siberian moth traps monitoring, they should be replaced biweekly with fresh septa for optimal trap effectiveness.  相似文献   

Revenue risk management, risk aversion and the use of Livestock Gross Margin for Dairy Cattle insurance   总被引：1，自引：0，他引：1  

Mayuri Valvekar  Jean P. Chavas  Brian W. Gould  Victor E. Cabrera 《Agricultural Systems》2011,104(9):671-678

The Livestock Gross Margin Insurance for Dairy Cattle is a federally reinsured insurance program that enables US dairy producers to establish minimum levels of milk income net of feed cost. Given the structure of this program there are an infinite number of possible contract designs based on the choice of deductible level and proportion of production insured. Adding to this complexity, producers vary in their risk preferences, which affect the incentive to insure their margin. It is unclear as to how producers may adopt this program for revenue risk management. This paper investigates the interplay between producer risk preferences, contract design and the subsidization of premium in determining program coverage. We undertook this analysis within an expected utility framework. Optimal contracts under different rates of constant relative rate of risk aversion and subsidies were analyzed using a nonlinear optimization model. We found that total optimal coverage increased significantly with the level of risk of aversion at lower deductibles but as deductible level increased, the level of risk aversion had a lesser impact on total optimal coverages. As expected, at the same deductible and risk aversion levels, inclusion of a premium subsidy increased the total optimal coverage.  相似文献   

Chiral fiber gratings     

Kopp VI  Churikov VM  Singer J  Chao N  Neugroschl D  Genack AZ 《Science (New York, N.Y.)》2004,305(5680):74-75

Chiral gratings with double helix symmetry were produced by twisting glass optical fiber with a noncircular core cross section as it passed through a miniature oven. We observed polarization-selective transmission in chiral fibers with pitches of tens of micrometers. Two modes of optical interaction were differentiated. In chirallong-period gratings, dips in transmission were observed at wavelengths associated with scattering into distinct cladding modes mediated by the chiral grating. In chiral intermediateperiod gratings, a broad scattering band was observed. These gratings can be used to produce sharp or broad polarization-selective filters.  相似文献   

Mutational analysis of the tyrosine phosphatome in colorectal cancers   总被引：1，自引：0，他引：1  

Wang Z  Shen D  Parsons DW  Bardelli A  Sager J  Szabo S  Ptak J  Silliman N  Peters BA  van der Heijden MS  Parmigiani G  Yan H  Wang TL  Riggins G  Powell SM  Willson JK  Markowitz S  Kinzler KW  Vogelstein B  Velculescu VE 《Science (New York, N.Y.)》2004,304(5674):1164-1166

Tyrosine phosphorylation, regulated by protein tyrosine phosphatases (PTPs) and kinases (PTKs), is important in signaling pathways underlying tumorigenesis. A mutational analysis of the tyrosine phosphatase gene superfamily in human cancers identified 83 somatic mutations in six PTPs (PTPRF, PTPRG, PTPRT, PTPN3, PTPN13, PTPN14), affecting 26% of colorectal cancers and a smaller fraction of lung, breast, and gastric cancers. Fifteen mutations were nonsense, frameshift, or splice-site alterations predicted to result in truncated proteins lacking phosphatase activity. Five missense mutations in the most commonly altered PTP (PTPRT) were biochemically examined and found to reduce phosphatase activity. Expression of wild-type but not a mutant PTPRT in human cancer cells inhibited cell growth. These observations suggest that the mutated tyrosine phosphatases are tumor suppressor genes, regulating cellular pathways that may be amenable to therapeutic intervention.  相似文献