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91.
Shinji  Junpei  Nohara  Setsuo  Yagi  Nobuyuki  Wilder  Marcy 《Fisheries Science》2020,86(3):601-601
Fisheries Science - The article "Bio-economic analysis of super-intensive closed shrimp farming and improvement of management plans: a case study in Japan", written by Junpei Shinji,...  相似文献   
92.
杨树不同无性系叶面积模型的选择及其建立   总被引:4,自引:1,他引:4  
刘建伟 Blake  TJ 《林业科学》1994,30(6):481-486
应用Li-3000A叶面积仪测定了8个无性系的叶型及叶面积指标,选择了8个模型,以叶片主脉长(L)和最大宽(W),以及两者乘积(L×W)为三个变量作与叶面积的相关关系分析,筛选出复相关系数均达0.95以上的最佳模型为:(1)与两者乘积的叶面积模型:lgY=a+bx+b+clgx,(2)与最大宽度的模型:Y=a+bx+cx2。但与叶片主脉长模拟效果较差。此外,还得出了杨树无性系的叶面积通用模型,即:Y=—0.450826十0.00071X+0.976335lgx(x为L×W),和Y=—1.697387十0.733497x—0.001253x2(x为W)。上述8个无性系及杨树通用的模型的建立为叶面积的计算、预测等生理生态研究提供了科学依据,使得叶面积测定更加省时、可靠和方便。  相似文献   
93.
Decades of intensive off‐road vehicle use for border security, immigration, smuggling, recreation, and military training along the USA–Mexico border have prompted concerns about long‐term human impacts on sensitive desert ecosystems. To help managers identify areas susceptible to soil erosion from anthropogenic activities, we developed a series of erosion potential models based on factors from the Universal Soil Loss Equation (USLE). To better express the vulnerability of soils to human disturbances, we refined two factors whose categorical and spatial representations limit the application of the USLE for non‐agricultural landscapes: the C‐factor (vegetation cover) and the P‐factor (support practice/management). A soil compaction index (P‐factor) was calculated as the difference in saturated hydrologic conductivity (Ks) between disturbed and undisturbed soils, which was then scaled up to maps of vehicle disturbances digitized from aerial photography. The C‐factor was improved using a satellite‐based vegetation index, which was better correlated with estimated ground cover (r2 = 0·77) than data derived from land cover (r2 = 0·06). We identified 9,780 km of unauthorized off‐road tracks in the 2,800‐km2 study area. Maps of these disturbances, when integrated with soil compaction data using the USLE, provided landscape‐scale information on areas vulnerable to erosion from both natural processes and human activities and are detailed enough for adaptive management and restoration planning. The models revealed erosion potential hotspots adjacent to the border and within areas managed as critical habitat for the threatened flat‐tailed horned lizard and endangered Sonoran pronghorn. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
94.
1-deoxynojirimycin (DNJ), a potent glucosidase inhibitor, is a characteristic constituent of the mulberry leaf. Dietary mulberry DNJ may be beneficial for the suppression of abnormally high blood glucose levels, thereby preventing diabetes mellitus. Although there is considerable interest in the effects of mulberry DNJ, the intestinal absorption and pharmacokinetic profile of orally administered mulberry DNJ have never been characterized. In this study, we developed a method for determining the level of plasma DNJ by hydrophilic interaction chromatography coupled to a mass spectrometric detector (HILIC-MS) to investigate the absorption and metabolism of orally administered mulberry DNJ in rats. DNJ was separated from plasma extract on a TSK gel Amide-80 column, a representative column for HILIC. At postcolumn, DNJ was concurrently detected and identified by MS. The plasma DNJ concentration in fasted rats was below the detection limit [<1 microg (6 nmol)/mL]; however, the concentration reached a maximum [15 microg (92 nmol)/mL] 30 min after the administration of mulberry DNJ (110 mg/kg of body weight), and the DNJ concentration decreased rapidly thereafter. When the rats received different amounts of mulberry DNJ (1.1, 11, and 110 mg/kg of body weight), dose-dependent incorporation of DNJ into the plasma was confirmed. We did not detect any DNJ metabolites in the plasma. These findings indicate that orally administered mulberry DNJ is absorbed as an intact form from the alimentary tract and then is quickly excreted from the body. The developed HILIC-MS method could be applied in determining levels of DNJ in urine and tissues, and therefore, the method would be a powerful tool for studying the metabolic fate of mulberry DNJ as well as its bioavailability.  相似文献   
95.
96.
Little is known about the distribution of Rhodococcus equi in the soil environment of native horses in China. One hundred and eight soil samples were collected from native-horse farms in the Hulun Beier grasslands of eastern Mongolia, the Xilin Goler grasslands of southern Mongolia, and Tongliao City in Inner Mongolia, China. The isolation rates of R. equi from soil samples from the Hulun Beier and Xilin Goler grasslands ranged from 25.9% to 30.0%. In contrast, isolation rates from soil samples from Tongliao City were as high as 82.3% and the mean number of R. equi in soil samples from Tongliao City was 10 times more than those of samples from the grasslands. The 488 isolates were examined using PCR for the presence of genes that encode virulence-associated 15-17 kDa antigen protein (VapA) and the 20 kDa antigen protein (VapB). All isolates were negative for virulence-associated proteins. Plasmid profiles of these avirulent isolates showed that cryptic plasmids of various sizes were present with an incidence of 13.3% to 21.5%. The results of the present study contrast with those of our recent study (J. Vet. Med. Sci. 67:611-613, 2005), in which we reported that R. equi was absent from Mongolian horses in Ulaanbaatar, Mongolia. It is suggested that the difference between the results of these two studies is due to the mobile pasturing system in Mongolia and nonmobile pasturing system in Inner Mongolia.  相似文献   
97.
To investigate the late effects of neutrons at the energy below 1 MeV on the liver carcinogenesis as a function of age, one-week old mice were exposed to 1.0 Gy monoenergetic neutrons (0.317, 0.525 and 1.026 MeV) or 137Cs gamma rays. Survival and carcinogenesis were examined by 18 months of age. Following radiation, tumor incidences in liver, Harderian gland, lung, ovary and pituitary gland were compared. The proportion of the lifespan with liver tumors exposed to neutrons to that exposed to gamma rays was calculated as a function of age. Survival rates among the three groups exposed to neutrons of different energies were not significantly different from one another but shorter than those treated with gamma rays for both sexes. With regard to liver tumor incidence evaluated at 18 months of age, the effectiveness of neutrons to gamma rays was 2.54 for females, and 2.08 for males by the factor. Levels of estrogen in the serum were similar between mice bearing liver tumors and those devoid of tumors. In conclusion, all three energies of neutrons induced similar effectiveness with respect to liver carcinogenicity. Proportions of the lifespan with liver tumors of neutron-exposed to gamma-exposed were shorter in females than males along with ages over 12 months. To obtain this factor at every age contributed for the evaluation of the biological effectiveness of radiations with the parameter of tumor incidence and latency simultaneously.  相似文献   
98.
Acute hypotonic stress becomes a threat to the survival of bacteria in the environment. Mechanosensitive channels play an essential role in the maintenance of bacterial cell integrity during hypoosmotic shock. A database search suggested that Campylobacter jejuni, a major worldwide cause of bacterial gastroenteritis in humans, possesses two putative mechanosensitive channels, designated Cjj0263 and Cjj1025, in C. jejuni strain 81-176. Osmotic downshock experiments demonstrated that a mutant lacking Cjj0263 showed a severe defect in survival of hypoosmotic shock, while a mutant lacking Cjj1025 exhibited the same survival capacity as the wild type. We further examined the colonization ability of each mutant using the one-day old chick model. Cjj0263 or Cjj1025 mutants were able to colonize chick ceca at the same level as the wild type, but a Cjj0263 Cjj1025 double mutant revealed significantly reduced ability to colonize chick ceca. To examine whether C. jejuni that have grown in the digestive tract of chicks are protected against acute hypotonic stress, bacteria in ceca were directly exposed to water. The wild type was able to survive acute osmotic downshift, but the Cjj0263 mutant suffered a substantial loss of viability when subjected to a rapid osmotic downshock. Immunoblot analysis suggested that both Cjj0263 and Cjj1025 were glycosylated via the N-linked protein glycosylation pathway, but glycan modification of these proteins was unlikely to have a major effect on their function and stability. Our data suggest that Cjj0263, a mechanosensitive channel, has a pivotal role in protection against hypoosmotic stress experienced during environmental transmission.  相似文献   
99.
A 2-year-old East Friesian sheep imported from Australia exhibited severe anemia after contagious pustular dermatitis in Hokkaido, Japan. Hemoplasma infection was confirmed in blood smears. Both Mycoplasma ovis and 'Candidatus Mycoplasma haemovis' were detected by PCR and sequence analyses. In the epidemiological analysis, dual pathogens were detected in 6 of 12 (50.0%) sheep imported from Australia with the infected ewe at the same time, 1 of 5 (20.0%) sheep introduced from a domestic farm in Hokkaido, and in 1 of 16 (6.3%) sheep from an epidemiologically unrelated ranch. It is the first clinical case of sheep to confirm coinfection of these pathogens in Japan.  相似文献   
100.
Recent analyses of Streptococcus suis isolates using multilocus sequence typing (MLST) suggested the importance of sequence type (ST) 1 and ST27 complexes for animal hygiene and public health. In this study, to investigate whether pilus-associated genes in S. suis can be used as novel genetic markers for important clonal groups, we examined the correlation between STs and putative pilus-associated gene profiles in S. suis. Genomic searches using sequenced genomes and sequence data determined in several isolates revealed the presence of at least four distinct putative pilus gene clusters in S. suis (srtBCD, srtE, srtF, and srtG clusters). On the basis of the presence or absence of genes in the four clusters, 108 S. suis isolates from various origins were classified into 12 genotypes (genotypes A–L). Genotypes A and B, which possessed srtBCD plus srtF clusters and srtF plus srtG clusters, respectively, were the most common in isolates from diseased pigs and humans, and 29.9% and 59.8% of the isolates belonged to genotypes A and B, respectively. In contrast, only 4.8% and 28.6% of isolates from healthy carriers were genotypes A and B, respectively. MLST analysis showed the associations of genotypes A and B with ST1 and ST27 complexes, respectively. In addition, srtBCD and srtG clusters were preferentially distributed to ST1 and ST27 complex members, respectively. These results suggest that profiling of selected pilus-associated genes could be used as an easy screening method to monitor isolates important for S. suis infection.  相似文献   
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