Predicting Long‐Term Changes in Riparian Bird Communities in Floodplain Landscapes

As anthropogenic impacts on riverine ecosystems expand, both aquatic and terrestrial ecosystems are influenced over large spatiotemporal scales. We predicted how riparian bird communities changed in response to long‐term changes in floodplain landscapes such as woodland expansion (i.e. rapid increases in vegetation cover on gravel bars and the progress of vegetation succession due to a decrease in the frequency and magnitude of flood disturbance). To test the hypothesis that woodland expansion after dam construction reduces the abundance of gravel bar‐nesting birds and increases the abundance of forest‐nesting birds, we estimated historical changes between past and present bird abundances using species distribution models across multiple rivers that were either unregulated or regulated by dams. We created past and present vegetation maps from remote sensing images and used habitat quantities as explanatory variables in the species distribution models. As we hypothesized, the estimated abundance of gravel bar‐nesting birds decreased and that of forest‐nesting birds increased because of woodland expansion in some regulated rivers. This suggests that anthropogenic alterations of riverine conditions (e.g. dam construction) can affect terrestrial ecosystems (e.g. riparian bird communities) through changes in floodplains (e.g. woodland expansion). In addition, our findings highlight the efficacy of combining spatial and temporal analyses when examining long‐term ecological dynamics. Copyright © 2013 John Wiley & Sons, Ltd.     

Retrospective memory bias for the frequency of potentially traumatic events: A prospective study.

We conducted a prospective study that tracked the frequency of potentially traumatic events (PTEs) and nontraumatic events among college students over a 4-year period using a weekly web-based survey. At the study's completion, participants attempted to recall the number of events they had endorsed on the web surveys. Although participants underrecalled the frequency of all types of life events, recollection was more accurate for PTEs than for non-PTEs. Recalled-frequency of PTEs was associated positively with distress at recall and inversely with trait self-enhancement. These effects were qualified by a distress × self-enhancement interaction. High distress at recall was associated with a greater recalled-frequency of PTEs, but only for people low in trait self-enhancement. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

基于改进回溯算法的计算机排课系统

计算机排课算法一直是一个没有被完美地解决的NP难题，国内外都在对它进行广泛的研究.基于一个中专院校的自动排课系统的实现，通过对当前各种算法的研究、对比、总结，发现当前的排课算法可以分为构造型算法和改进型算法两类，并且这两种算法有着各自的优缺点.为此吸取了遗传算法(改进型算法)和回溯法(构造型算法)的优点，在回溯法中引入了拟人策略和遗传算法中的评价、惩罚机制，经过实际应用的验证，该算法特别适合应用在实际的排课系统中.     

基于RS和GIS技术的生态环境影响回顾性评价——以福建紫金山矿区为例

在实际调查的基础上,采用RS、CIS等高新技术相结合的方法对福建紫金山矿区的生态环境信息进行解译提取和分析对比。结果表明,紫金山矿山严发对矿区生态环境造成了一定程度的破坏,植被覆盖率降低．土地利用类型也发生了转变,土壤侵蚀作用增强,评价区周边侵蚀类型和强度变化不大。     

如何利用临床资料进行回顾性队列研究

临床病例资源丰富,但往往存在基线资料不全、非随机分组导致混杂因素多、失访率高等问题,限制了临床医生利用这些数据开展研究。采用限制、配对、分层、多因素分析、倾向性评分等多种方法可以克服已有临床病例资料的固有缺陷,从而得出可靠结论。本文从队列研究的设计、分析、论文撰写等方面阐述如何进行高质量的临床研究。     

Stimulus salience and retrospective revaluation.

The effect of conditioning or extinguishing the more salient element of a previously reinforced compound on responding to the less salient element of that compound was assessed in rats. Experiment 1 established that the 2 elements making up an audiovisual compound differed significantly in salience. In Experiment 2A, compound conditioning was followed by either reinforcement or extinction of either the less or more salient element. On test, evidence of retrospective revaluation of the less salient element was found but not of the more salient element. In Experiment 2B, extinction of the more salient element was found to be more effective than its reinforcement in producing retrospective revaluation of the less salient element. The implications of these results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recursive retrospective revaluation of causal judgments.

Recursive causal evaluation is an iterative process in which the evaluation of a target cause, T, is based on the outcome of the evaluation of another cause, C, the evaluation of which itself depends on the evaluation of a 3rd cause, D. Retrospective revaluation consists of backward processing of information as indicated by the fact that the evaluation of T is influenced by subsequent information that is not concerned with T directly. Two experiments demonstrate recursive retrospective revaluation with contingency information presented in list format as well as with trial-by-trial acquisition. Existing associative models are unable to predict the results. The model of recursive causal disambiguation that conceptualizes the revaluation as a recursive process of disambiguation predicts the pattern of results correctly. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

一种改进的稀疏度自适应弱选择匹配追踪算法

针对实际水声信道无法获知先验稀疏度和导频资源问题,提出一种改进的稀疏度自适应弱选择匹配追踪算法(MSASWOMP)。将稀疏度初始估计作为初始支撑集的大小,对原子进行阈值弱选择得到的原子支撑集作为回溯筛选的候选集;再以初始支撑集大小为回溯开始初始条件值进行二次筛选;最后利用变阶段步长方法进行稀疏度逐步精确估计,自适应更新回溯开始条件值。仿真实验分析了阈值参数、稀疏度估计步长和导频数目对于MSASWOMP算法的影响,结果表明,该算法能以更少的导频数目获得更精确的信道估计值,节省导频资源的同时,其均方误差(MSE)优于传统算法。     

The relationship of hope in the future and perceived school climate to school completion.

This study examined the impact of hope in the future and school climate as protective factors in school dropouts and graduates. Participants consisted of 97 students (males and females, aged 14-21 yrs) at risk for not completing school in an urban area. At-risk status was determined by student assignment to a continuation high school, a special placement for students who had had numerous infractions at regular high schools. Retrospectively, dropouts rated perceived school climate significantly lower than graduates, and graduates rated the importance of attending college significantly higher than dropouts. Dropouts and graduates who left school after the study was conducted did not report differences on the risk factors measured, nor did they differ on perceived school climate or the importance of attending college. However, hope in the future significantly predicted dropout versus graduate status for these participants. Results are discussed as describing differences in retrospective versus prospective reports, and as evidence of the utility of the risk/resilience paradigm in school completion research. (PsycINFO Database Record (c) 2011 APA, all rights reserved)