Conservation and control strategies for the wolf (Canis lupus) in western Europe based on demographic models

Securing the long-term acceptance of large carnivores such as the wolf (Canis lupus) in Europe and North America raises a difficult challenge to conservation biologists: planning removals to reduce depredations on livestock while ensuring population viability. We use stochastic-stage-structured population models to investigate wolf population dynamics and to assess alternative management strategies. Among the various management strategies advocated by agencies, zoning that involves eliminating wolves outside a restricted area should be designed with caution, because probabilities of extinction are extremely sensitive to the maximum number of packs that a zone can support and to slight changes in stage specific survival probabilities. In a zoned population, viability is enhanced more by decreasing mortality rates in all classes than by increasing wolf zone size. An alternative to zoning is adaptive management, where there is no limit on pack number but population control can be operated whenever some predefined demographic conditions are met. It turns out that an adaptive management strategy that removes a moderate percentage (10%) of the population following each year of more than 5% of total population growth would provide visible actions addressing public concerns while keeping extinction probability low.     

Modeling of the effects of IL-17 and TNF-α on endothelial cells and thrombus growth

Rheumatoid and psoriatic arthritis are chronic inflammatory diseases, with massive increase of cardiovascular events (CVE), and contribution of the cytokines TNF-α and IL-17. Chronic inflammation inside the joint membrane or synovium results from the activation of fibroblasts/synoviocytes, and leads to the release of cytokines from monocytes (Tumor Necrosis Factor or TNF) and from T lymphocytes (Interleukin-17 or IL-17). At the systemic level, the very same cytokines affect endothelial cells and vessel wall. We have previously shown [1], [2] that IL-17 and TNF-α, specifically when combined, increase procoagulation, decrease anticoagulation and increase platelet aggregation, leading to thrombosis. These results are the basis for the models of interactions between IL-17 and TNF, and genes expressed by activated endothelial cells. This work is devoted to mathematical modeling and numerical simulations of blood coagulation and clot growth under the influence of IL-17 and TNF-α. We show that they can provoke thrombosis, leading to the complete or partial occlusion of blood vessels. The regimes of blood coagulation and conditions of occlusion are investigated in numerical simulations and in approximate analytical models. The results of mathematical modeling allow us to predict thrombosis development for an individual patient.     

石蒜Mg^2＋转运体基因LrMGT的克隆与分析

从石蒜〔Lycoris radiata（L’Hér.）Herb.〕叶片全长cDNA文库中克隆获得Mg^2＋转运体（MGT）基因LrMGT。序列分析结果显示：LrMGT基因的cDNA序列全长1 726 bp,其中开放阅读框（ORF）长度921 bp,编码306个氨基酸。石蒜LrMGT基因编码的氨基酸序列的理论相对分子质量为33 635,理论等电点为pI 5.14,为疏水性膜蛋白,不具有信号肽。序列比对结果表明：石蒜LrMGT基因编码的氨基酸序列与小米〔Setaria italica（Linn.）Beauv.〕、水稻（Oryza sativa Linn.）和拟南芥〔Arabidopsis thaliana（Linn.）Heynh.〕等植物的MGT基因编码的氨基酸序列的相似性较高,相似度达到72%~76%;石蒜LrMGT基因与其他植物MGT基因编码的氨基酸序列的保守区域较大,均具有较高的保守性。在NJ系统树上石蒜LrMGT基因编码的氨基酸序列与禾本科（Gramineae）植物二穗短柄草〔Brachypodium distachyum（Linn.）Beauv.〕、水稻、高粱〔Sorghum bicolor（Linn.）Moench〕和小米MGT基因编码的氨基酸序列聚为同一个分支,表明它们可能具有较近的进化关系。实时荧光定量PCR结果表明：石蒜LrMGT基因在根和鳞茎中的相对表达量较高,在叶片和花中的相对表达量较低,具有明显的组织特异性。     

Early prehistory of South America and population dynamics: Issues and hypotheses

People were in the Americas before, during, and immediately after the Last Glacial Maximum. Multiple data converge toward a deep chronology model for Homo genre exploration, dispersal, occupation, and settlement across the continent. South America is not an exception. This paper is an attempt to think of South America record in terms of population dynamics within a Paleolithic reflection: What are the anthropological implications of a longer and therefore slower peopling process? What modes of expansion, rhythms, adaptations, routes could be traced base especially in lithic records? What kind of archaeological manifestations should we expect in the different environments that make up an immense and highly diverse geography? What modes of technological continuity and change could be linked to these manifestations? Although further research is still needed to address these questions, our goal is to contribute to posing the problem in the most holistic way possible, linking climate, environment, and techno-cultural data within and beyond South America, in order to model how populations might have expanded and contracted at different periods throughout this subcontinent.     

石器研究中“操作链”的概念、内涵及应用

作为旧石器研究中十分重要的研究概念之一, 本文对"操作链"的发展史、理论内涵、实践方法等方面进行讨论, 认为"操作链"概念是一种动态的、综合的理论视角和研究体系, 强调了石器技术系统的两个行为过程(技术表现与思维运作)和一个互动关系(操作序列)。实践应用和术语对比, 为更好地运用"操作链"研究石器并复原史前技术体系提供了参考。文章还提出了"操作链"概念本身存在的问题, 希望能在今后的工作中得到完善。     

Climate and health: Observation and modeling of malaria in the Ferlo (Senegal)

The aim of this work, undertaken in the framework of QWeCI (Quantifying Weather and Climate Impacts on health in the developing countries) project, is to study how climate variability could influence malaria seasonal incidence. It will also assess the evolution of vector-borne diseases such as malaria by simulation analysis of climate models according to various climate scenarios for the next years. Climate variability seems to be determinant for the risk of malaria development (Freeman and Bradley, 1996 [1], Lindsay and Birley, 1996 [2], Kuhn et al., 2005 [3]). Climate can impact on the epidemiology of malaria by several mechanisms, directly, via the development rates and survival of both pathogens and vectors, and indirectly, through changes in vegetation and land surface characteristics such as the variability of breeding sites like ponds.     

The “Megalithisation” of Iberia: A spatio-temporal model

In the last 20 years, the growing availability of radiometric data has led to profound changes in the archaeological study of cultural and social processes in European Late Prehistory. In this paper, we examine how the combined use of spatial analysis and Bayesian modelling can further contribute to an enhanced interpretation of the temporality of a major social phenomenon: the “megalithisation” process in Iberia. For the first time, it is possible to compare hypotheses regarding the start date, speed and direction of the spread of this major process for the whole of Iberia, and not just for selected regions or single sites.     

一类生物种群投资的最优采收控制

在原有的Gauss白噪声刻画环境噪声项的基础上,考虑环境不可预知的跳跃性变化,运用Lévy白噪声建立了有界环境中的随机生物种群模型.并且,引入随机奇异控制来描述投资者的最优采收策略.进一步地,构造一族有着不同起点的控制问题,利用动态规划的思想,给出了最优采收控制问题解的充分条件,进而,将随机控制问题的求解转化为确定型偏微分方程的求解.     

鲜切生菜中沙门氏菌二级生长预测模型的建立

以鲜切生菜为研究对象,比较了修正的Gompertz、Gompertz、Logistic和MMF 4种一级模型对不同温度下鲜切生菜中沙门氏菌生长曲线的拟合情况,发现在36℃、20℃和10℃时,修正的Gompertz模型均为最佳的拟合模型,4℃时沙门氏菌生长受到抑制,对失活/存活曲线进行"镜像化"处理后发现拟合程度相对较低,相关系数为0.962 7,故未用于二级模型中;采用其他温度下的修正的Gompertz模型中的最大比生长速率作为二级模型的响应值,建立平方根二级模型;准确因子和偏差因子对二级模型的准确性验证结果表明,两者均接近1.0,说明所建立的二级模型用于预测鲜切生菜中沙门氏菌生长情况。本研究为鲜切生菜的微生物安全控制提供科学依据。