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21.
Long-term monitoring is key for detecting population declines. Composite indices allow researchers to combine trends from disparate monitoring programmes into a single estimate of population change. Inferences from composite indices, however, are limited to the time periods and areas studied. We show that the number of breeding pairs in a colony of Cape Vultures Gyps coprotheres in South Africa declined between the years 1983 and 2003 but increased in both the number of breeding pairs and fledglings per pair from 2004 to 2017. We performed a retrospective power analysis determining the minimum annual frequency with which the colony could have been monitored without sacrificing inference into population trends. This power analysis revealed the post-2003 population increase would not have been apparent if we skipped more than 2 years between surveys. We incorporated our estimates into a previously published composite index for Cape Vultures that considered only data collected pre-2000 and demonstrate that the inference is unchanged if the trend from the decline period or the entire study is incorporated, yet if only the trend during the period of population increase is used, there is no longer a statistically significant decline across the species’ range. Our results demonstrate the utility of long-term monitoring because if our study had concluded before 2003, there would be little evidence of the current population increase at Kransberg. 相似文献
22.
Yong Shu Liang Xiao Deng ZhanHui Mming Wang Zhi Qiang GaoZe chuan Lin Dai Bo ChenXi Hong Shen Li Yong Cao Shi Hua Cheng 《Gene》2013
This study aimed to elucidate the genetics of the adult root system in elite Chinese hybrid rice. Several adult root traits in a recombinant inbred line (RIL) population of Xieyou 9308 and two backcross F1 (BCF1) populations derived from the RILs were phenotyped under hydroponic culture at heading stage for quantitative trait locus (QTL) mapping and other statistical analysis. There a total of eight QTLs detected for the root traits. Among of them, a pleiotropic QTL was repeatedly flanked by RM180 and RM5436 on the short arm of chromosome 7 for multiple traits across RILs and its BCF1 populations, accounting for 6.88% to 25.26% of the phenotypic variances. Only additive/dominant QTLs were detected for the root traits. These results can serve as a foundation for facilitating future cloning and molecular breeding. 相似文献
23.
Ana C.F. Ribeiro Marigese B.B.J. Rita Abílio J.F.N. Sobral Victor M.M. Lobo Miguel A. Esteso 《Molecular simulation》2013,39(6):510-514
The estimation of numerical values of the mean distance of closest approach of ions, a, of heavy metal ion salts in aqueous solutions, determined from activity coefficients, as well as from different theoretical approaches, is presented and discussed. 相似文献
24.
Luca Ferretti Sebastián E. Ramos‐Onsins Miguel Pérez‐Enciso 《Molecular ecology》2013,22(22):5561-5576
Next generation sequencing of pooled samples is an effective approach for studies of variability and differentiation in populations. In this paper we provide a comprehensive set of estimators of the most common statistics in population genetics based on the frequency spectrum, namely the Watterson estimator , nucleotide pairwise diversity Π, Tajima's D, Fu and Li's D and F, Fay and Wu's H, McDonald‐Kreitman and HKA tests and , corrected for sequencing errors and ascertainment bias. In a simulation study, we show that pool and individual θ estimates are highly correlated and discuss how the performance of the statistics vary with read depth and sample size in different evolutionary scenarios. As an application, we reanalyse sequences from Drosophila mauritiana and from an evolution experiment in Drosophila melanogaster. These methods are useful for population genetic projects with limited budget, study of communities of individuals that are hard to isolate, or autopolyploid species. 相似文献
25.
以新安江干流(安徽段)滩涂湿地草本植物群落为研究对象,探讨其区系组成及不同江段物种多样性的变化规律.结果表明:(1)该区共有草本被子植物48科、131属、194种(含种下分类单位);以禾本科(Gramineae)、莎草科(Cyperaceae)、菊科(Compositae)和蓼科(Polygonaceae)为优势科;以蓼属(Polygonum)、莎草属(Cyperus)、大戟属(Euphorbia)和蒿属(Artemisia)等为优势属,属的组成相对较为分散,寡种属和单种属占总属数的97.7%;(2)从分布区类型看,科以世界分布占明显优势(43.8%);属的分布区类型以泛热带分布最多(30.5%),其次是世界分布(26.0%),总体上热带成分略多于温带成分(57/40);表明该区草本植物区系地理成分较为复杂,分布区类型多样,具有热带、亚热带与暖温带的多重性质,但以亚热带性质为主;(3)各滩涂湿地植物群落的建群种、优势种及伴生种的种类等组成特征均存在一定差异,狗牙根(Cynodon dactylon)、双穗雀稗(Paspalum distichum)和假俭草(Eremochloa ophiuroides)等为滩涂湿地的主要优势种;江段干流不同流域滩涂湿地草本植物群落的α多样性的变化格局与丰富度指数的变化格局比较一致,总体上呈现逐渐减小的趋势,表现为上游>中游>下游;与之相反,植物群落的β多样性——相异性系数和Cody指数总体上呈现上升的格局.这种多样性格局的成因需要进一步分析和探讨. 相似文献
26.
Pathophysiology of white-nose syndrome in bats: a mechanistic model linking wing damage to mortality
Lisa Warnecke James M. Turner Trent K. Bollinger Vikram Misra Paul M. Cryan David S. Blehert Gudrun Wibbelt Craig K. R. Willis 《Biology letters》2013,9(4)
White-nose syndrome is devastating North American bat populations but we lack basic information on disease mechanisms. Altered blood physiology owing to epidermal invasion by the fungal pathogen Geomyces destructans (Gd) has been hypothesized as a cause of disrupted torpor patterns of affected hibernating bats, leading to mortality. Here, we present data on blood electrolyte concentration, haematology and acid–base balance of hibernating little brown bats, Myotis lucifugus, following experimental inoculation with Gd. Compared with controls, infected bats showed electrolyte depletion (i.e. lower plasma sodium), changes in haematology (i.e. increased haematocrit and decreased glucose) and disrupted acid–base balance (i.e. lower CO2 partial pressure and bicarbonate). These findings indicate hypotonic dehydration, hypovolaemia and metabolic acidosis. We propose a mechanistic model linking tissue damage to altered homeostasis and morbidity/mortality. 相似文献
27.
G. Kishan P. Gopalakannan C. Muthukumaran K. Thirumalai Muthukumaresan M. Dharmendira Kumar K. Tamilarasan 《Journal of Genetic Engineering and Biotechnology》2013,11(2):111-116
Statistical optimization is an effective technique for the investigation of complex processes with minimal number of experimental runs. In this study, statistical approach was used to study the optimization of media components for lipase production from Yarrowia lipolytica MTCC 35. Mahua cake, glucose, MnCl2 and KH2PO4 were screened to be the most significant variables among the nine medium variables that were tested to determine influence on lipase production by Plackett–Burman design. Central Composite Design was used for further optimization of these screened variables for enhanced lipase production. The determination coefficient (R2) value of 0.922 showed that the regression models adequately explain the data variation and represent the actual relationships between the variables and response. The optimum values of investigated variables for the maximum lipase production were 6.0% Mahua cake, 2.0% glucose, 0.2% MnCl2 and 0.2% KH2PO4. The maximum lipase production (9.40 U mL?1) was obtained under optimal condition. 相似文献
28.
Hexagonal Boron Nitride‐Based Electrolyte Composite for Li‐Ion Battery Operation from Room Temperature to 150 °C 下载免费PDF全文
Marco‐Tulio F. Rodrigues Kaushik Kalaga Hemtej Gullapalli Ganguli Babu Arava Leela Mohana Reddy Pulickel M. Ajayan 《Liver Transplantation》2016,6(12)
Batteries for high temperature applications capable of withstanding over 60 °C are still dominated by primary cells. Conventional rechargeable energy storage technologies which have exceptional performance at ambient temperatures employ volatile electrolytes and soft separators, resulting in catastrophic failure under heat. A composite electrolyte/separator is reported that holds the key to extend the capability of Li‐ion batteries to high temperatures. A stoichiometric mixture of hexagonal boron nitride, piperidinium‐based ionic liquid, and a lithium salt is formulated, with ionic conductivity reaching 3 mS cm?1, electrochemical stability up to 5 V and extended thermal stability. The composite is used in combination with conventional electrodes and demonstrates to be stable for over 600 cycles at 120 °C, with a total capacity fade of less than 3%. The ease of formulation along with superior thermal and electrochemical stability of this system extends the use of Li‐ion chemistries to applications beyond consumer electronics and electric vehicles. 相似文献
29.
Combining Nature‐Inspired,Graphene‐Wrapped Flexible Electrodes with Nanocomposite Polymer Electrolyte for Asymmetric Capacitive Energy Storage 下载免费PDF全文
Two kinds of free‐standing electrodes, reduced graphene oxide (rGO)‐wrapped Fe‐doped MnO2 composite (G‐MFO) and rGO‐wrapped hierarchical porous carbon microspheres composite (G‐HPC) are fabricated using a frozen lake‐inspired, bubble‐assistance method. This configuration fully enables utilization of the synergistic effects from both components, endowing the materials to be excellent electrodes for flexible and lightweight electrochemical capacitors. Moreover, a nonaqueous HPC‐doped gel polymer electrolyte (GPE‐HPC) is employed to broad voltage window and improve heat resistance. A fabricated asymmetric supercapacitor based on G‐MFO cathode and G‐HPC anode with GPE‐HPC electrolyte achieves superior flexibility and reliability, enhanced energy/power density, and outstanding cycling stability. The ability to power light‐emitting diodes also indicates the feasibility for practical use. Therefore, it is believed that this novel design may hold great promise for future flexible electronic devices. 相似文献
30.
Frederic Bartumeus Daniel Campos William S. Ryu Roger Lloret‐Cabot Vicenç Méndez Jordi Catalan 《Ecology letters》2016,19(11):1299-1313
Understanding the structural complexity and the main drivers of animal search behaviour is pivotal to foraging ecology. Yet, the role of uncertainty as a generative mechanism of movement patterns is poorly understood. Novel insights from search theory suggest that organisms should collect and assess new information from the environment by producing complex exploratory strategies. Based on an extension of the first passage time theory, and using simple equations and simulations, we unveil the elementary heuristics behind search behaviour. In particular, we show that normal diffusion is not enough for determining optimal exploratory behaviour but anomalous diffusion is required. Searching organisms go through two critical sequential phases (approach and detection) and experience fundamental search tradeoffs that may limit their encounter rates. Using experimental data, we show that biological search includes elements not fully considered in contemporary physical search theory. In particular, the need to consider search movement as a non‐stationary process that brings the organism from one informational state to another. For example, the transition from remaining in an area to departing from it may occur through an exploratory state where cognitive search is challenged. Therefore, a more comprehensive view of foraging ecology requires including current perspectives about movement under uncertainty. 相似文献