Evaluating Alternative Strategies for Minimizing Unintended Fitness Consequences of Cultured Individuals on Wild Populations

Artificial propagation strategies often incur selection in captivity that leads to traits that are maladaptive in the wild. For propagation programs focused on production rather than demographic contribution to wild populations, effects on wild populations can occur through unintentional escapement or the need to release individuals into natural environments for part of their life cycle. In this case, 2 alternative management strategies might reduce unintended fitness consequences on natural populations: (1) reduce selection in captivity as much as possible to reduce fitness load (keep them similar), or (2) breed a separate population to reduce captive‐wild interactions as much as possible (make them different). We quantitatively evaluate these 2 strategies with a coupled demographic–genetic model based on Pacific salmon hatcheries that incorporates a variety of relevant processes and dynamics: selection in the hatchery relative to the wild, assortative mating based on the trait under selection, and different life cycle arrangements in terms of hatchery release, density dependence, natural selection, and reproduction. Model results indicate that, if natural selection only occurs between reproduction and captive release, the similar strategy performs better. However, if natural selection occurs between captive release and reproduction, the different and similar strategies present viable alternatives to reducing unintended fitness consequences because of the greater opportunity to purge maladaptive individuals. In this case, the appropriate approach depends on the feasibility of each strategy and the demographic goal (e.g., increasing natural abundance, or ensuring that a high proportion of natural spawners are naturally produced). In addition, the fitness effects of hatchery release are much greater if hatchery release occurs before (vs. after) density‐dependent interactions. Given the logistical challenges to achieving both the similar and different strategies, evaluation of not just the preferred strategy but also the consequences of failing to achieve the desired target is critical. Evaluación de Estrategias Alternativas para Minimizar las Consecuencias No Inesperadas en la Adecuación de Individuos Criados en Cautiverio sobre Poblaciones Silvestres     

A fuzzy DEMATEL method to evaluate critical operational hazards during gas freeing process in crude oil tankers

Gas freeing process in crude oil tanker ships is widely recognized one of the most hazardous aspects of shipboard operations. Although the process provides practical benefits to ship by removing the explosive or poisonous gases from the cargo tanks and raising the oxygen level up to 21 percent, the consequences of failure may cause serious damage to human health, marine environment and cargo. Therefore, the crew exercise utmost care and become aware of the potential hazards in gas freeing process. In this context, this paper provides a fuzzy DEMATEL (Decision Making Trial and Evaluation Laboratory) method to evaluate critical operational hazards in gas freeing process. While the DEMATEL method enables to identify and analyse the potential hazards of gas freeing process with respect to causal–effect relation diagram, fuzzy sets deal with the uncertainty in decision-making and human judgements through the DEMATEL. Thus, the hybrid approach provides smart solution for safety practitioners to prevent critical hazards in gas freeing process. The results of the research will contribute to maritime safety at sea and prevention of environment pollution as well as loss of life on-board crude oil tankers ships.     

云南蒋家沟流域泥石流沟谷演变的非线性特征

蒋家沟是我国西南山区一条典型的暴雨泥石流沟，位于云南省东北部金沙江支流小江河谷的右岸。主沟长13.9km，流域面积48.6km^2，平均纵坡比降16.02%，流域内有4级支沟。据统计，沟谷长度大于0.50km的各级泥石支沟有26条，其中主沟1条（即蒋家沟）,另含Ⅰ级支沟6条，Ⅱ，Ⅲ，Ⅳ级支沟各2，7和10。蒋家沟流域内各级泥石流支沟尽管在形态上具有自相似性，但在空间分布上则具有均一性，从各支沟的数目、密度和流域面积看，均表明由沟口至沟源（尾）有逐渐增强的趋势，且主要集中在门前、多照两沟内。对蒋家沟及流域内各泥石流支沟的沟谷形态分析显示，各支沟的流域面积、沟道坡降及长度均存在明显的分形特征，它们与沟道数目之间有良好的非线性关系。这种非线性关系一 定程度上揭示了这些泥石流沟谷演变的非均匀性和自相似性。     

Gas and Organic Matter in Last Glacial and Holocenic Sediments of Venice Lagoon

Two drills (MBM1* and MBM2) provided at “Bocca di Malamocco” gave environmental and palaeo-environmental information on sedimentation for the last 50,000 years. the MBM2 supplies textural, gas and organic matter studies of sediment and principal ion content of pore water. Two main palaeo-environments, divided in six cycles, are recognized. Marine environment characterizes the sediment above 12.80 metres below sea level (mbsl) and continental environment dominates the sediments below.

The concentration/depth profiles of dissolved ammonia, phosphates and gases are related to the occurrence of a relatively high organic content in the sediment core. Carbon dioxide to methane ratio shows a constant value below 20 mbsl, while above that level only carbon dioxide was detected. A sulphate gradient in the transition zone between the marine to fresh water interval suggests a methane oxidation. These findings indicate that diffusive transport of methane from marine sediments to the atmosphere may be considered minimal. the sedimentary cycles are related to the oxygen isotopic stages. They suggest a variable hydraulic regime occurred during the last Glacial time in the palaeo-plain corresponding to the present Venice lagoon.     

甘肃窑街煤矿二氧化碳突出及防治

本文对甘肃窑街煤矿特大型二氧化碳突出的特征、地质构造背景及防治工作进行了研究。研究结果表明突出气体是煤系自燃热解所生成,根据对方解石脉进行裂变径迹测年和气体的氩同位素研究,表明气体形成于晚第三纪至早更新世;突出区大量CO_2气主要受断裂构造与强应力场控制而蕴藏在厚煤层中。 打前探孔、震动放炮、抽放卸压等措施对于防治突出,减少损失具有积极的作用,而厚煤层中的断裂带部位是最危险的区段,应重点防范。     

Relatedness and sex ratio in a primitively eusocial halictine bee

Lasioglossum laevissimum was studied in Calgary, Alberta, where it is eusocial with one worker brood. Estimates of relatedness were obtained among various categories of nestmate based upon four polymorphic enzyme loci, two of which exhibited significant levels of linkage disequilibrium. Relatedness estimates among workers and among reproductive brood females were very close to the expected 0.75 value that obtains when nests are headed by one, singly mated queen. However, relatedness between workers and the reproductive brood females they reared was significantly lower than 0.75. A low frequency of orphaning with subsequent monopolisation of oviposition by one worker brood female in orphaned nests may explain these results. Workers were significantly more and queens significantly less closely related to male reproductives than expected if all males were to have resulted from queen-laid eggs. Orphaning and worker-produced males contribute to this result. The sex investment ratio was 1:2.2 in favour of females, in excellent agreement with the predictions based upon relative relatednesses between workers and reproductive brood males and females. Adaptive intercolony variation in investment ratios was detected: the sex ratio was more heavily female-biased in nests in which the relative relatedness asymmetry between workers and reproductive brood was more female-biased. The study species is the most weakly eusocial hymenopteran for which relatedness estimates and sex ratio data are available. With high relatedness among nestmates and a strongly female-biased sex ratio, this study suggests the importance of indirect fitness contributions in the early stages of social evolution. Correspondence to: L. Packer     

重庆市农业转型发展的时空演进及问题区识别——基于全要素生产率视角

研究农业全要素生产率时空演进规律对于合理制定农业转型升级政策具有重要意义。在使用DEA-Malmquist指数模型测算出重庆市37个县（区）2000-2016年农业全要素生产率增长的基础上,结合空间分析方法和核密度估计方法考察农业TFP的时空演进特征,并识别出问题区域。研究表明：（1）2000-2016年间重庆市农业全要素生产率呈上升趋势,农业TFP指数呈“U”型和阶段性波动的变化趋势,并且表现出明显的空间不平衡性。（2）农业TFP指数增减趋势与技术进步指数的变化趋势基本一致,技术进步是影响农业全要素生产率的主要因素。（3）从全市来看,农业TFP的核密度曲线不断向右移动,且波峰高度持续上升,波峰形态由“单峰”分布向“多峰”分布转变,说明重庆市农业全要素生产率的地区差距在考察期内呈增大趋势。（4）依据TFP增长、技术进步和技术效率的关联关系,识别出三种类型的问题区域,并针对每类问题区域提出农业转型发展的政策建议。     

中国居民消费磷足迹时空格局及驱动因素研究

在磷足迹内涵界定及其计算模型构建的基础上,探究了中国城乡居民食物消费磷足迹的时空格局,并解析了其驱动机制.结果表明：1978~2018年间,中国食物消费磷资源和磷污染足迹分别增长了6倍和4倍,达到2018年的715.9万t和78.7万t,其中城镇居民是主要贡献源,占比分别达到67%和64%.从结构上看,城乡食物消费磷资源足迹均由荤食主导,其中家禽、水产品和蛋奶消费的磷资源足迹占比不断增加;而磷污染足迹主要源于上游食物生产过程,其中种植业和水产养殖业增幅最为显著.我国31个省市食物消费磷资源足迹和磷污染足迹在空间分布上具有一致性,呈现从东向西减小的趋势,东部省市诸如广东、上海、江苏、北京和山东等远高于其他地区,并且具有高度的空间集聚性,在东部沿海形成高-高（H-H）聚集区.因此调控磷开发利用活动的资源环境压力需要着眼于这些重点区域.我国食物消费磷足迹增长的关键驱动因素是利用效率下降、消费水平提升和饮食结构改变,因此有效提升食物生产的养分利用效率和引导合理的消费理念和饮食习惯是减缓磷的开发活动资源环境压力的重要途径.     

新疆入境旅游发展的空间差异及其演变趋势分析

基于新疆2001-2010年旅游外汇收入指标,对新疆入境旅游发展的空间差异和演变趋势进行了定量分析.结果表明：近10年来新疆入境旅游发展的空间格局发生了较大变化,且存在明显的区域极化现象;新疆旅游外汇收入的“省域差异”、“地带内差异”和“北疆差异”变化趋势高度一致;自然条件的显著差异,旅游资源的空间集聚分布以及区位和交通条件的空间差异,是新疆入境旅游空间差异形成的主要影响因素.     

Formation and Evolution of Ancient Lakes on South Coast Plain of Laizhou Bay

Abstract

Based on the data of historical geography, the analysis of the stratigraphic section, and the textual research of place names and satellite photographic interpretations, the authors study the formation and evolution of ancient lakes on the south coast plain of Laizhou Bay where there were once three lakes: Judian Lake, Qingshuibo Lake and Biehua Lake. All the lakes formed 6000 years ago evolved from the lagoons near the estuary and went through two periods, the golden age in the Middle Holocene and the shrinking age in the Late Holocene. The disappearance of the lakes resulted from the drying climate, the migration of the river courses and the activities of human beings. Among the three reasons, the migration of the river courses is the main one.