首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 234 毫秒
1.
2.
3.
《动物学报》2007,53(6):1145-1146
Acta Zoologica Sinica is a bimonthly, peer-reviewed journal and publishes original articles, reviews, viewpoints, research methods, information about academic conferences and reviews on new books in all aspects of Zoology, and particularly welcome contributions in research fields of ecology,behaviorial biology, evolutionary biology and biogeography.  相似文献   

4.
《动物学报》2004,50(4):F005-F006
Acta Zoologica Sinica is a bimonthly, peer-reviewed journal and publishes original articles, reviews, viewpoints, research methods, information about academic conferences and reviews on new books in all aspects of Zoology, and particularly welcome contributions in research fields of ecology, behaviorial biology, evolutionary biology and biogeography.  相似文献   

5.
《动物学报》2004,50(6):i011-i012
Acta Zoologica Sinica is a bimonthly, peer-reviewed journal and publishes original articles, reviews, viewpoints, research methods, information about academic conferences and reviews on new book sin all aspects of Zoology, and particularly welcome contributions in research fields of ecology, behaviorial biology, evolutionary biology and biogeography.  相似文献   

6.
7.
8.
Science in China Series C: Life Sciences, an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China, and p  相似文献   

9.
10.
《Cell research》2006,16(3):329-330
  相似文献   

11.
A multi-trait index for ranking different genetic groups/populations with homogeneous covariance structure is developed and illustrated with live data.  相似文献   

12.
A new plan quality index integrating dosimetric and radiobiological indices was proposed to facilitate the evaluation and comparison of simultaneous integrated boost (SIB) intensity modulated radiotherapy (IMRT) plans for nasopharyngeal cancer (NPC) patients.Ten NPC patients treated by SIB-IMRT were enrolled in the study. Custom software was developed to read dose–volume histogram (DVH) curves from the treatment planning system (TPS). A plan filtering matrix was introduced to filter plans that fail to satisfy treatment protocol. Target plan quality indices and organ at risk (OAR) plan quality indices were calculated for qualified plans. A unique composite plan quality index (CPQI) was proposed based on the relative weight of these indices to evaluate and compare competing plans. Plan ranking results were compared with detailed statistical analysis, radiation oncology quality system (ROQS) scoring results and physician's evaluation results to verify the accuracy of this new plan quality index.The average CPQI values for plans with OAR priority of low, normal, high, and PTV only were 0.22 ± 0.08, 0.49 ± 0.077, 0.71 ± 0.062, and −0.21 ± 0.16, respectively. There were significant differences among these plan quality indices (One-way ANOVA test, p < 0.01). This was consistent with statistical analysis, ROQS results and physician's ranking results in which 90% OAR high plans were selected.Plan filtering matrix was able to speed up the plan evaluation process. The new matrix plan quality index CPQI showed good consistence with physician ranking results. It is a promising index for NPC SIB-IMRT plan evaluation.  相似文献   

13.
Numerous indicator approaches are found in the scientific literature to describe changes in biodiversity. It is however far from clear which indicators are most appropriate and which are less suitable to summarize trends in biodiversity. One reason for this lack of clarity is that so far the mathematical properties of indicator approaches have had little attention. In this paper, we derive a number of desirable mathematical properties of indicators from economic price-index theory and apply these in the form of tests to 10 metrics to summarize changes in biodiversity. The metrics species richness, Simpson index, Shannon index, Buckland's modified Shannon index and Sørensen's similarity coefficient violate the monotonicity and proportionality test. The percentage of increasing minus declining species also fails the proportionality test, and in the case where trends are assessed relative to the preceding year, this metric also violates the identity test. Most of these indicators are sensitive to spatial scale. The arithmetic and geometric mean of population indices and the mean abundance have better mathematical performance, but the first two are sensitive to appearing and disappearing species in the system surveyed. The metric mean abundance however can only be applied under particular conditions and has some undesirable properties. Unlike the arithmetic mean, the geometric mean is not sensitive to the base year chosen and has the most favourable mathematical properties of the indicators evaluated. The geometric mean can be straightforwardly extended to take into account unequal values of species if desired.  相似文献   

14.
Too hot for comfort: The heatwaves in Greece in 1987 and 1988   总被引:1,自引:0,他引:1  
The heatwaves that affected Greece in July 1987 and July 1988 are considered in terms of (i) the relative strain index. For different types of activity, and (ii) the discomfort index. Hourly values of air temperature and humidity for Thessaloniki and Athens were used as the data base. Both indices show that in terms of physiological strain and general discomfort, Thessaloniki suffered a little more and a little longer than Athens. We conclude that the relative strain index is probably a useful tool in studies of the adverse effects of humid heatwaves on different sections of a population.  相似文献   

15.
Summary Conventional selection index theory assumes that the total merit or profitability of animals is a linear function of measurable traits. However, in many cases merit may be a non-linear function of these traits. A linear selection index can still be used in this situation but the optimum index depends on the selection intensity to be used and on the number of generation over which the selection response is to be maximized. Nonlinear selection indices have been suggested but these result in a lower selection response than the best linear index. Linear selection indices suggested in the past are shown to correspond to the optimum linear index for either a very small selection response or, in the case of restricted indices, a very large selection response. The economic value of a trait may depend on management decisions taken by the farmer. In this situation the economic values should be calculated assuming that the management decisions taken maximize profit given the present genetic value of the animals.  相似文献   

16.
中国自然保护区区域评价模型的建立与应用   总被引:2,自引:1,他引:1  
戎可    马建章    赵丹  吴庆明 《生态学报》2008,28(6):2738-2738~2745
在综合分析中国自然保护区现状的基础上,提取数量、面积、生境破碎化、人口压力、经济开发压力5个要素建立中国自然保护区区域评价模型.模型由胁迫指数(IP)、状态指数(IS)、保护需求指数(CI)3个指数构成指标体系.提出了自然保护区有效性权重系数,用以将不同级别不同管理水平的自然保护区统一纳入到评价模型中,在一定程度上消除了自然保护区间保护水平差异对区域评价准确性的影响.应用该模型对中国大陆各省及各行政区间保护区发展水平进行了评价.结果表明,中国西部各省保护区(例如ISNorthwest China =10.82)建设状况良好,而东部经济发达省份,特别是华东地区的保护区当前状态(ISEast China =4.82)低于全国整体水平(ISNation wide =6.50).同时,东部各省面临更大的潜在保护压力(例如IPEast China =10.99,IPNation wide=9.21).应首先调整华东、华中、华南省份的保护区建设规划,同时加大投入、加强管理,加强西部省份经济活动对保护区管理和功能的影响的监测.  相似文献   

17.
Affordable and easy-to-use methods for assessing biomass and leaf area index (LAI) would be of interest in most breeding programs. Here, we describe the evaluation of a protocol for photographic sampling and image analysis aimed at providing low-labor yet robust indicators of biomass and LAI. In this trial, two genotypes of triticale, two of bread wheat, and four of tritordeum were studied. At six dates during the growing cycle, biomass and LAI were measured destructively, and digital photography was taken on the same dates. Several vegetation indices were calculated from each image. The results showed that repeatable and consistent values of the indices were obtained in consecutive photographic samplings on the same plots. The photographic indices were highly correlated with the destructive measure-ments, though the magnitude of the correlation was lower after anthesis. This work shows that photographic assess-ment of biomass and LAI can be fast, affordable, have good repeatability, and can be used under bright and overcast skies. A practical vegetation index derived from pictures is the fraction of green pixels over the total pixels of the image, and as it shows good correlations with all biomass variables, is the most robust to lighting conditions and has easy interpretation.  相似文献   

18.
The relative toxicity of pesticides to Phyllocnistis citrella and its parasitoid Ageniaspis citricola was compared by several bioassay methods. A clip-cage bioassay measured survival of adults exposed to fresh residues at 0.25-times (0.25×), 0.5×, 1×, and 2× the lowest recommended rate of each pesticide, a water control (0×), and 24- and 48-h aged residues of oil at 1.5% (1×) rate. A one-species cylinder bioassay determined the effects of pesticides on immature stages of the citrus leafminer after treating young citrus trees with the same rates of pesticides (except for avermectin, tested at 0×, 0.01×, 0.025×, 0.05×, 0.1×, and 0.25× rates). A sublethal rate of petroleum oil (0.4%) was added as an adjuvant in some treatments. The effect of pesticides on immature stages of A. citricola was determined with a two-species cylinder bioassay after treating young citrus trees with the same rates as above. An index of IPM compatibility was developed based on the efficacy of the pesticide as a control agent of the leafminer (or other pests) and its selectivity to the parasitoid at the lowest recommended field rate (0.25× the field rate for avermectin). Azadirachtin (Neemix) + oil, diflubenzuron (Micromite) + oil, fenoxycarb (Eclipse) + oil, and oil alone (FC 435-66) were classified as IPM-compatible insecticides. Sprays of azadirachtin (Align) + oil, neem oil (Neemgard), and drenched imidacloprid (Admire) were ranked as a semi-compatible insecticides. The fungicide copper hydroxide (Kocide 101) and a fish oil-based foliar fertilizer (Zapata HFE) were considered compatible. Avermectin (Agri-Mek) + oil, ethion (Ethion), and imidacloprid (Provado) applied as a spray were IPM-incompatible insecticides. These products should be tested under field conditions to confirm these ratings.  相似文献   

19.
临安市雷竹林土壤重金属污染特征及生态风险评价   总被引:13,自引:0,他引:13  
为了解临安市雷竹林土壤重金属污染特征,采集并测定了160个土壤样品的Hg、As、Cu、Pb、Zn、Cd、Cr、Ni、Co、Mn等重金属含量,采用单因子污染指数和内梅罗综合污染指数对雷竹林土壤重金属污染程度进行分析,并应用Hankanson潜在生态风险指数法对雷竹林土壤重金属潜在生态风险进行评价.结果表明:雷竹林土壤重金属Hg、As、Cu、Pb、Zn、Cd、Cr、Ni、Co、Mn的平均含量分别为0.16、7.41、34.36、87.98、103.98、0.26、59.12、29.56、11.44、350.26mg·kg-1,Pb、Cd、Zn和Cu平均值超过浙江省土壤背景值,分别是对应背景值的2.89、1.70、1.12、1.12倍.经单因子污染指数评价,不同重金属元素的平均污染程度大小依次为Pb>Cd>Cu=Zn>Hg>As>Ni>Co>Cr>Mn,其中Pb有中度污染,Cd、Cu和Zn有轻度污染.经内梅罗综合污染指数评价,160个样点都受到不同程度的重金属污染,轻度污染、中度污染和重度污染水平所占比率分别为55.6%、29.4%和15.0%.各重金属单因子潜在生态风险指数平均值评价结果显示,只有Cd污染达到中等生态风险,其他重金属均为轻微生态风险,而局部采样点Cd和Hg单因子潜在生态风险指数最大值分别达到256.82和187.33,存在很强生态风险.重金属综合因子潜在生态风险指数评价结果表明,临安市雷竹林土壤整体上存在轻微生态风险.  相似文献   

20.
对14批静注丙球保留样品进行3年效期内稳定性观察结果表明:出厂后3年内制品的物理检查和热稳定性试验均合格,pH值没有变化,IgG分子仍以单体形式存在,抗补体活性(ACA)和PKA含量未见升高,白喉抗毒素效价未见下降。表明我所大规模生产的静注丙球质量是稳定可靠的  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号