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31.
32.
Sigurd Schulz Wolfgang Kaiser Günther Breuel 《International Review of Hydrobiology》1991,76(3):351-359
Eutrophication of the nature is one of the most relevant problems for the human society today. In comparison to terrestrial and limnological ecosystems, however, the marine environment is affected with some exceptions of coastal waters in a minor degree. On the basis of data from 1976–1988 trend analysis for chlorophyll, primary production, zooplankton biomass and water transparency have been carried out for the Mecklenburg Bight and different areas of the Baltic proper. As expected from the longterm increase in the nutrient levels, also for some pelagic biological variables increasing trends could be observed. At least for chlorophyll they are significant in the 95% probability level for all investigated areas. Primary production shows also an increase, however, not significant for each subarea. For zooplankton nearly no changes could be observed. All data reflect a high interannual variability, which can partly be explained by meteorological and oceanological conditions. The results are discussed from an ecological point of view. The increase in phytoplankton variables is considered to be at least partly related to the eutrophication of the Baltic. 相似文献
33.
Danielle K. Walkup Anna Michelle Lawing Toby J. Hibbitts Wade A. Ryberg 《Ecology and evolution》2022,12(2)
The western massasauga (Sistrurus tergeminus) is a small pit viper with an extensive geographic range, yet observations of this species are relatively rare. They persist in patchy and isolated populations, threatened by habitat destruction and fragmentation, mortality from vehicle collisions, and deliberate extermination. Changing climates may pose an additional stressor on the survival of isolated populations. Here, we evaluate historic, modern, and future geographic projections of suitable climate for S. tergeminus to outline shifts in their potential geographic distribution and inform current and future management. We used maximum entropy modeling to build multiple models of the potential geographic distribution of S. tergeminus. We evaluated the influence of five key decisions made during the modeling process on the resulting geographic projections of the potential distribution, allowing us to identify areas of model robustness and uncertainty. We evaluated models with the area under the receiver operating curve and true skill statistic. We retained 16 models to project both in the past and future multiple general circulation models. At the last glacial maximum, the potential geographic distribution associated with S. tergeminus occurrences had a stronghold in the southern part of its current range and extended further south into Mexico, but by the mid‐Holocene, its modeled potential distribution was similar to its present‐day potential distribution. Under future model projections, the potential distribution of S. tergeminus moves north, with the strongest northward trends predicted under a climate scenario increase of 8.5 W/m2. Some southern populations of S. tergeminus have likely already been extirpated and will continue to be threatened by shifting availability of suitable climate, as they are already under threat from desertification of grasslands. Land use and habitat loss at the northern edge of the species range are likely to make it challenging for this species to track suitable climates northward over time. 相似文献
34.
This study was done to provide an overview of the latest trichomoniasis status in Korea by finding disease clusters and analyzing temporal trends during 2012–2020. Data were obtained from the Health Insurance Review & Assessment Service (HIRA) of Korea. SaTScan and Joinpoint programs were used for statistical analyses. Gyeonggi-do had the highest average population and highest number of cases. The high incidence of T. vaginalis infections were observed among women aged 40–49 and 30–39 years (33,830/year and 33,179/year, respectively). Similarly, the 40–49 and 30–39 age group in men showed the highest average cases (1,319/year and 1,282/year, respectively). Jeollabuk-do was the most likely cluster, followed by Busan/Gyeongsangnam-do/Ulsan/Daegu and Jeju-do and Gwangju. Urban and rural differences were prominent. Trichomoniasis has decreased significantly in most clusters, except for Incheon. Trichomoniasis was decreasing in women recently after peaking around 2014. Men showed different trends according to age. Trichomoniasis was increasing in the 10–39 age groups, but decreasing in the 40–59 age groups. This study might provide an analytic basis for future health measures, policy-makers, and health authorities in developing effective system for prevention of trichomoniasis. 相似文献
35.
新疆土地荒漠化及其防治对策 总被引:3,自引:0,他引:3
1 荒漠化土地分布现状1.1 分 布北倚阿尔泰山南麓,南亘昆仑山北麓,东至甘、新和中蒙边界,西达哈萨克斯坦荒漠。新疆荒漠化土地地理垂直分布相差悬殊,准噶尔盆地海拔179~1000m,塔里木盆地海拔780~1500m,昆仑山、阿尔金山、天山南坡海拔1500~3100m,阿尔金山库木库里盆地海拔3900~5000m,而吐鲁番盆地为-154m。在昆仑山和阿尔金山北坡、天山南北坡、阿尔泰山南坡的山前洪积平原上分布着大面积卵砾粗岩片碎石戈壁。在罗布泊、乌尔禾谷地、吐鲁番盆地、英吉沙、库车、莎车等县的洪积细土平原和湖积平原高台地上,分布着风蚀残丘(雅丹地… 相似文献
36.
Charles Susanne 《Journal of human evolution》1985,14(4):357-370
37.
Jürg Hüsler 《Biometrical journal. Biometrische Zeitschrift》2009,51(2):252-272
We review some approaches of extreme value analysis in the context of biometrical applications. The classical extreme value analysis is based on iid random variables. Two different general methods are applied, which will be discussed together with biometrical examples. Different estimation, testing, goodness‐of‐fit procedures for applications are discussed. Furthermore, some non‐classical situations are considered where the data are possibly dependent, where a non‐stationary behavior is observed in the data or where the observations are not univariate. A few open problems are also stated. 相似文献
38.
《Animal : an international journal of animal bioscience》2015,9(10):1617-1623
Death of calves around parturition is a matter of concern for dairy farmers. Relatively high stillbirth rates and unfavourable trends have been reported for Holstein heifers in the Netherlands and several other countries. In our study, we investigated herd differences, genetic parameters and genotype by environment interaction for heifer calf livability. A large dataset with data from calvings between 1993 and 2012 of Dutch dairy farms was used. There were considerable differences between herds in livability of calves from heifers, with averages ranging from 74% to 95%. Both herds with relatively high and low averages showed the same negative trend between 1993 and 2012, with largest declines in herds with the lowest averages. We found that heritability and genetic variation of first parity livability were substantially larger in herd environments where the likelihood of stillbirth was high v. environments where stillbirth was at a low level. The genetic correlations between herd environment levels were all very close to unity, indicating that ranking of sires was similar for all environments. However, for herds with a relatively high stillbirth incidence selecting sires with favourable breeding values is expected to be twice as profitable as in herds with a relatively low stillbirth incidence. 相似文献
39.
This study aims to reveal the secular trends in body mass index (BMI) and the prevalence of overweight and obesity among Polish schoolchildren between the years 1966–2012, during which intense socio-political changes took place. Four surveys were conducted in several districts of Poland looking at 69,746 schoolchildren aged 7–18. Significant increase in mean BMI as well as in the prevalence of overweight and obesity was observed. During this time the highest increase in both mean BMI and excess weight was observed between 1988 and 2012, i.e. after the political transformation, resulting in the improvement of living conditions. However, with respect to girls in late adolescence, between these years, the mean BMI as well as the prevalence of overweight were leveling off, while the percentage of boys with excess body fat in the same developmental category significantly increased in 2012. In the years 1966–1978 and 1978–1988 the pattern of changes in the prevalence of overweight and obesity reflected the social and economic circumstances, i.e. temporary economic improvements, or deepening political crises and food shortage. In conclusion, the weight status of schoolchildren strongly reflects socio-political changes that took place in Poland, as well as in most of the Central European countries in the last half century. 相似文献
40.