大别山-桐柏山地区杀虫性植物资源调查初报

大别山、桐柏山属于亚热带向暖温带过渡地气候 ,是植物区系的交接过渡地带 ,既有亚热带典型的代表型 ,又体现着过渡性的特征。能产生具有杀虫活性的次生代谢产物的植物即杀虫性植物。通过广泛调查、采集与鉴定 ,大别山—桐柏山地区分布有杀虫性植物 72科 138种     

研究森林变化对河川水沙影响的一种便捷方法──以四川省都江堰市白沙河为例

依据航片判读、森林资源调查资料和水文数据，利用流域自身对比法，得出森林变化对河川径流泥沙的定量关系。文中还阐明本方法的技术关键——消除降雨量不同对水沙的影响．该方法具有适合我国国情、费小效宏、精度较高、简捷易行等优点，值得推广提倡。     

湖南省土地荒漠化和沙化监测布局与监测方法

我省土地荒漠化和沙化监测主要包括3个荒漠化监测站和5个沙化监测站，布设监测样地28个。确定了采集监测区域内气象、土壤、水文、生物等方面的信息和方法。     

Trends in NE Atlantic landings (southern Portugal): identifying the relative importance of fisheries and environmental variables

Time series of commercial landings from the Algarve (southern Portugal) from 1982 to 1999 were analyzed using min/max autocorrelation factor analysis (MAFA) and dynamic factor analysis (DFA). These techniques were used to identify trends and explore the relationships between the response variables (annual landings of 12 species) and explanatory variables [sea surface temperature, rainfall, an upwelling index, Guadiana river (south‐east Portugal) flow, the North Atlantic oscillation, the number of licensed fishing vessels and the number of commercial fishermen]. Landings were more highly correlated with non‐lagged environmental variables and in particular with Guadiana river flow. Both techniques gave coherent results, with the most important trend being a steady decline over time. A DFA model with two explanatory variables (Guadiana river flow and number of fishermen) and three common trends (smoothing functions over time) gave good fits to 10 of the 12 species. Results of other models indicated that river flow is the more important explanatory variable in this model. Changes in the mean flow and discharge regime of the Guadiana river resulting from the construction of the Alqueva dam, completed in 2002, are therefore likely to have a significant and deleterious impact on Algarve fisheries landings.     

Relationships between catch and effort in Fijian multispecies reef fisheries subject to different levels of exploitation

Abstract The catch-per-unit-effort (CPUE) and value-of-catch-per-unit-effort (VPUE) of reef-associated fish species from six Fijian native fishing grounds ( qoliqoli ) subject to different fishing intensities were determined using records of fishing activity from a voluntary logbook scheme. Line and spear fishing techniques were used for more than half the total fishing time (h person^-1 d^-1) in all qoliqoli , and yet the favoured technique in a given qoliqoli was frequently less efficient (lower CPUE) than other techniques. The popularity of relatively ineffective fishing methods implies that fishermen did not always attempt to maximize their catch rates. To compare fishing effort in different qoliqoli , all effort was rescaled on the basis of its recorded efficiency (measured as multispecies CPUE) and expressed as hours equivalent to boat-based spear fishing over coral by day to catch fish for sale. Total fishing intensity in the six qoliqoli ranged from 72 to 4310 h km^-2 reef year^-1. The relationship between catch and effort was linear at all fishing intensities, suggesting that the qoliqoli were all fished on a sustainable basis. Furthermore, whilst there was a significant difference in CPUE and VPUE between the one or two qoliqoli with lowest fishing intensity and all the others, there were no significant differences between these other qoliqoli in terms of the VPUE of the saleable multispecies boat catch or the CPUE of species from piscivorous and carnivorous genera ( Epinephelus, Lethrinus and Plectropomus ) which the fishermen prefer to catch.     

An investigation of uncertainty in field habitat mapping and the implications for detecting land cover change

Land cover data for landscape ecological studies are frequently obtained by field survey. In the United Kingdom, temporally separated field surveys have been used to identify the locations and magnitudes of recent changes in land cover. However, such map data contain errors which may seriously hinder the identification of land cover change and the extent and locations of rare landscape features. This paper investigates the extent of the differences between two sets of maps derived from field surveys within the Northumberland National Park in 1991 and 1992. The method used in each survey was the Phase 1 approach of the Nature Conservancy Council of Great Britain. Differences between maps were greatest for the land cover types with the smallest areas. Overall spatial correspondence between maps was found to be only 44.4%. A maximum of 14.4% of the total area surveyed was found to have undergone genuine land cover change. The remaining discrepancies, equivalent to 41.2% of the total survey area, were attributed primarily to differences of land cover interpretation between surveyors (classification error). Differences in boundary locations (positional error) were also noted, but were found to be a relatively minor source of error. The implications for the detection of land cover change and habitat mapping are discussed.     

A seroepidemiological study on bluetongue virus in dairy cattle in the central valley of California

A seroepidemiological study on bluetongue virus (BTV) infection in California dairy cattle was conducted to estimate the prevalence and distribution by age and season of BTV group-reactive antibodies and to look for possible associations between the presence of antibodies and cattle age or breed and farm. Between December 1985 and March 1987, a sample of cattle was tested at approximately two-month intervals for BTV group-reactive antibodies using an enzyme-linked immunosorbent assay (ELISA). Data taken during the month of December 1986 were used to evaluate possible associations between a positive antibody test and certain intrinsic (age, breed) and extrinsic (farm) factors.Univariate and multivariate statistical analyses using the -square test for associations and multiple logistic regression, respectively, were carried out for possible associations between positive antibody tests to BTV and each factor of interest. The strengths of the associations were determined using estimates of the odds ratio.Of the 3774 serum samples tested, 238 (6.3%) were from calves, 1045 (27.6%) were from heifers and 2492 (66.0%) were from cows. Seroprevalence varied from nil in calves on two occasions to over 90% on several occasions in cows. Cows consistently had higher prevalence rates than heifers or calves across all test dates (p<0.05). The seroprevalence of BTV group-reactive antibodies also showed a seasonal fluctuation, with the highest rates occurring during the warmer months of the year. These highest prevalence rates coincided with heavy activity of the known vector of BTV, Culicoides spp. Breed and farm effects were not statistically significant (p>0.05). With the exception of one farm, all cattle were of the Holstein breed, which reduced confidence in assessing any breed effect in this study. Relative estimates of the sensitivity and specificity of BTV ELISA were 87% and 100% respectively, compared to the standard agar gel immunodiffusion (AGID) test.The observations support previous findings of seasonal distribution of BTV antibodies and suggest an age relationship, whereby older cattle are more likely to be positive to BTV group-reactive antibodies than younger cattle.     

Caspase非依赖性细胞死亡的研究进展

细胞凋亡是一种生理性细胞死亡机制，它是由多基因调控的一种细胞的主动的自杀性过程。一般认为它是由蛋白酶caspases通过两种途径激活的。但是，近年来研究发现除caspases引起的细胞凋亡外，还有caspases非依赖性的细胞死亡形式存在，包括细胞的自我吞噬作用、细胞蛋白酶体的降解和线粒体途径。这些途径无论是在试验的条件下还是在生理或病理的情况下都可以观察到。目前认为凋亡诱导因子(AIF)在caspases非依赖性的细胞死亡中起关键作用。