排序方式： 共有9条查询结果，搜索用时 281 毫秒
1
1.
Douglas P. Peterson Bruce E. Rieman Dona L. Horan Michael K. Young 《Ecology of Freshwater Fish》2014,23(4):556-571
Habitat fragmentation in aquatic systems has led to widespread isolation of stream fishes. Metapopulation theory predicts that persistence is directly related to local patch size and its characteristics, but because these relationships tend to be taxon‐specific, empirical data are important. We assembled 246 observations of occurrence of westslope cutthroat trout (WCT), a taxon of concern in the western U.S. and Canada, in stream networks isolated for up to 100 years (median 40 years) above human‐made barriers, mostly culverts, at road crossings within U.S. National Forests. We used logistic regression to analyse how WCT occurrence varied with patch size, isolation time and stream‐level covariates. Occurrence was positively related to stream length and habitat quality within the isolated stream network and negatively related to elevation and channel gradient. Unexpectedly, the probability of occurrence was not related to how long a habitat patch had been isolated. At the median elevation (1354 m) and channel gradient (14%), and where habitat quality was poor, WCT were likely to occur (probability >0.5) if an isolated stream network was at least 1.7 km. If habitat quality was high, about 0.2 km of habitat produced the same probability. Although there are important limitations, this analysis provides the first empirical estimate for how patch size and patch‐level characteristics influence persistence of WCT in isolated stream networks. 相似文献
2.
Wasanthika Harshini Galpottage Dona Jeff J. Schoenau Tom King 《Journal of plant nutrition》2020,43(6):879-895
AbstractLegumes have a unique ability to obtain a significant portion of atmospheric nitrogen (N2) through a symbiotic relationship with Rhizobia spp of bacteria but it takes time, thus, an early supply of N to the plant may positively influence growth and development. However, too much fertilizer in close proximity to the seed can damage the seedling. Therefore, this study was conducted to determine the maximum safe rates for starter seed-row fertilizer application under low seedbed utilization conditions (15%). Emergence, biomass yield and nitrogen (N), phosphorus (P) and sulfur (S) uptake responses to starter fertilizer products and blends applied at 0, 10, 20 and 30?kg?N?ha?1 in the seed-row were investigated for six different pulse crops: soybean, pea, faba bean, black bean, lentil and chickpea. The general sensitivity (injury potential) for starter N, P, S fertilizer was lentil?≥?pea?≥?chickpea?>?soybean?≥?black bean?>?faba bean. Lentil, pea and chickpea could generally only tolerate the 10?kg?N?ha?1 rates while soybean and black bean could tolerate 10–20?kg?N?ha?1. Faba bean emergence appeared relatively unaffected by all three rates of N and showed least sensitivity to seed row placed fertilizer. In terms of 30-day biomass response, soybean and black bean were most responsive to fertilization, while pea, faba bean, lentil and chickpea were least responsive to the starter fertilizer applications, with no benefit increasing above the 10?kg?N?ha?1 rate. 相似文献
3.
Karthikeyan K. Kumar A. T. Manish Harshini D. Pooja G. Daniel J. Arul Yasam Pavani Gracevictoria G. Priayanka M. Krishnaraj P. Vidya R. Devi S. Asha Reddy Sabbasani Rajasekhara Sudhakaran Raja 《Aquaculture International》2022,30(2):989-998
Shrimp farming industries are subjected to severe economic loss due to a disease called white spot syndrome, a viral disease caused by white spot syndrome virus (WSSV) in penaeid shrimp. Numerous active compounds in the market possess anti-viral activity against the white spot syndrome virus, yet the issue remains unsolved. The present study was carried out to determine the anti-viral activity of methyl 1-chloro-7-methyl-2-propyl-1h-benzo[d] imidazole-5-carboxylate (C13H15N2O2Cl) against WSSV. The anti-viral activity of the synthetic compound was determined in freshwater crabs. Crabs were divided into three different experimental groups: healthy control groups (N.C.) received NTE buffer, positive control group (P.C.) crabs received WSSV, and treatment group crabs received WSSV along with synthetic weight compound. Experimental groups were observed for 30 days post-infection. Three different organs (gills, muscles, and head soft tissue (HST)) were dissected from all three groups and analyzed using molecular-based techniques, including polymerase chain reaction (PCR), Western blot, and histopathology. Clinical signs of WSSV were observed in the positive and N.C. groups; however, the treatment group showed a 100% survival rate. Confirmation was done using PCR, Western blot, and histopathology. These results demonstrated that the given synthetic compound has significant anti-viral activity against WSSV.
相似文献4.
1. Positive heterosis effects for the proportion of yolk, and negative heterosis for the proportion of albumen were found in crosses of six inbred Leghorn lines. 2. Three‐way crosses showed no consistent change in egg composition when compared with matched two‐way crosses. 3. Large differences in egg composition were found between inbred lines. 4. The egg composition of two‐way crosses was highly predictable from the performance of their parents, while specific combining effects as measured by deviations from offspring—parent regression were relatively unimportant. 相似文献
5.
6.
Bandula Kumara WICKRAMASEKARA RAJAPAKSHAGE Janaka Pradeep Kumara ELLEARAEWE GARUHAMILAGE Dona Daphney Niranjala DE SILVA Ashoka DANGOLLA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2016,78(1):1-5
The purpose of this prospective study was to establish the ultrasonographic
characteristics of the dimension of the right pancreatic lobe with that of the associated
anatomic landmarks in healthy dogs. Ultrasonographic examinations were performed on 25
dogs. The thickness of the right pancreatic lobe was compared with that of mural thickness
of duodenum, diameter of duodenum, pancreatic duct, abdominal aorta, portal vein, caudal
vena cava, and length and width of the right kidney and right adrenal gland. The
correlation between each pancreatic parameter and the dimensions of the anatomical
landmarks were assessed using linear regression analysis and Pearson’s correlation
coefficient (r) test. Significant, but weak linear correlations were observed between
thickness of right pancreatic lobe with that of duodenum mural thickness (r=0.605,
R2=0.339, P=0.001); duodenum diameter (r=0.573,
R2=0.299, P=0.003); and right adrenal gland length (r=0.508,
R2=0.052, P=0.01). There was no significant dimensional
relationship with other selected anatomic landmarks. The ratio between the thickness of
right pancreatic lobe and the mural thickness of duodenum, diameter of duodenum and length
of right adrenal gland were 2.88 ± 0.53, 1.27 ± 0.27 and 0.81 ± 0.15, respectively.
Calculating the ratio of thickness of the right pancreatic lobe with the dimension of
significantly correlated anatomic landmarks is a useful and simple method for evaluating
the size of the right pancreatic lobe in dogs in clinical practice. 相似文献
7.
1. Data from 16 inbred lines derived by three generations of full sib mating from a common outbred base population were used to estimate genetic correlations between body weight, abdominal fat content, follicle number, liver weight, egg weight and egg number using between‐line variances and covariances. 2. High genetic correlations were found between body weight, fat content and egg weight. Low genetic correlations were found between follicle number and all traits other than egg weights. 3. Theoretical expectations and low correlations within lines led to the conclusion that environmental correlations among the traits considered were very low. 相似文献
8.
Grazieli Maboni E. Jane Kelly Chad S. Clancy Eliana De Luca Thomas J. Baldwin Arnaud J. Van Wettere Albert J. Kane Summer Peterson V. Gus Warr Dona A. Bastian Susan Sanchez 《Journal of veterinary diagnostic investigation》2022,34(1):167
A mortality event among recently captured feral donkeys (Equus asinus) occurred in south-central Utah in 2016. The deaths were sporadic, and clinical signs were indicative of respiratory disease, likely associated with an infectious etiology. Ten of 13 donkeys autopsied had moderate-to-severe interstitial fibrosing pneumonia, and one had pyogranulomatous pneumonia. Consensus PCRs directed toward the DNA polymerase and DNA packaging terminase subunit 1 for herpesviruses were performed followed by sequencing of the PCR amplicons and phylogenetic analysis. Asinine herpesvirus 4 (AsHV4) and 5 (AsHV5) were consistently identified in lung tissues of affected donkeys. No other herpesviruses were identified, and herpesviral DNA was not detected in lung tissues of 2 donkeys without evidence of respiratory disease. The detection of asinine gammaherpesviruses may have been associated with the lesions described. AsHV4 and AsHV5 have been reported in previous studies as novel gammaherpesviruses based on sequences obtained from donkeys with interstitial pneumonia and marked syncytial cell formation. Our findings suggest that the association of asinine gammaherpesviruses with respiratory conditions in equids deserves further attention. 相似文献
9.
Small-scale Forestry - This study employs in-depth qualitative and quantitative research methods including survey and other ethnographic methods, concept mapping and informal qualitative... 相似文献
1