学业不良大学生的人格特征分析

大学生学业不良主要是指由于焦虑等心理因素影响大学生学习潜力的发挥,造成学习效果不理想的状况,并且学习成绩未达到在读高校的既定标准。学习成绩结果具有暂时性、可逆性、具体性、社会性等特征。近年来,学业不良大学生的队伍不断扩大,学者们开始关注这个特殊群体。研究表明,学生的学习成绩与人格存在一定的相关。本文从学业不良的定义入手,分析了国内外对学业不良的研究现状,然后,着重对学业不良大学生的人格特征方面的研究进行综述,并提出一些相关建议。     

Comparison of trait associations in adapted × exotic matings of sorghum developed by two introgression methods

The association among six traits in the F₂ lines derived from adapted × exotic backcrosses of sorghum developed via two introgression methods was studied using principal component analysis. The first principal component defined a hybrid index in matings of the wild accession (12–26) but not in matings of the cultivated sorghum genotypes (Segeolane and SC408), no matter which adapted parent was used. This component accounted for 27–42% of the total variation in each mating. The recombination spindle was wide in all matings of CK60 and KP9B, which indicated that the relationships among traits were not strong enough to restrict recombination among the parental characters. The index scores of both CK60 and KP9B matings showed clear differentiation of the backcross generations only when the exotic parent was the undomesticated wild accession (12–26). None of the distributions of the first principal component scores in any backcross population was bimodal. The frequency of recombinant genotypes derived from a mating was determined by the level of domestication and adaptation of the exotic parent and the genetic background of the adapted parent. Backcrossing to a population (KP9B) was found to be superior to backcrossing to an inbred line (CK60) to produce lines with an improved adapted phenotype.Contribution no. 93-574-J from the Kansas Agricultural Experiment Station.     

Calculating independent contrasts for the comparative study of substitution rates

Phylogenetic comparative methods have been used to study patterns of correlated evolution between biological traits of all kinds, and are increasingly used to identify predictors of the rate of DNA substitution. Substitution rate differs from most traits studied in that it cannot be observed directly, but must be inferred from substitutions accrued over a long period of time. Studying a mathematical model of trait and rate evolution, we show that the special nature of substitution rates can lead to a severe loss of power for standard comparative methods. We further show how strategies designed to maximise power, by increasing the number of data points, can have the opposite effect when substitution rate is involved. We then propose two modifications of the standard methods that can mitigate these problems. First, we show how pre-existing tests for homogeneity of variance can be used to identify and exclude those data from which changes in substitution rate cannot be reliably inferred. Second, we show that power can be increased by comparing substitution rate with the time average of the predictor trait along the history of the lineage, and introduce a maximum likelihood estimator of this quantity.     

Delay discounting: trait variable?

Delay discounting refers to the tendency for outcomes that are remote in time to have less value than more immediate outcomes. Steep discounting of delayed outcomes is associated with a variety of social maladies. The degree of sensitivity to delayed outcomes may be a stable and pervasive individual characteristic. In analyses of archival data, the present study found positive correlations between the degree of delay discounting for one outcome (as measured by the Area Under the Curve), and the degree of discounting for other outcomes. Along with additional evidence reviewed, these data suggest that delay discounting may be considered a personality trait. Recent research in epigenetics, neuroscience, and behavior suggests delay discounting may prove to be a beneficial target for therapeutic attempts to produce global reductions in impulsivity related to delay discounting.     

化疗期乳腺癌患者情绪状态及其影响因素的调查研究

目的:调查化疗期乳腺癌患者的抑郁及焦虑情绪状态,探讨情绪状态的影响因素,促使医护人员更好的了解化疗期乳腺癌患者的情绪状态,以便更好的提供相应的护理与治疗。方法:采用自行设计的调查问卷,对2012年7~12月住院的97名化疗期乳腺癌患者进行调查,内容包括一般人口学资料、医院焦虑抑郁量表及状态-特质焦虑问卷。结果:化疗期乳腺癌患者的抑郁得分为(4.79±4.23)分,特质焦虑得分为(41.70±11.81)分,状态焦虑得分为(40.61±12.11)分,其影响因素包括教育水平和家庭人均月收入,Pearson相关分析得出特质焦虑、状态焦虑与抑郁之间存在正相关。结论:化疗期乳腺癌患者焦虑与抑郁处于较高水平,教育水平越高、家庭人均月收入越高的患者其焦虑、抑郁程度越低。医护人员可以通过对化疗期乳腺癌患者进行相应的心理疏导以减轻负性情绪的产生,以促进和保持治疗的顺利进行与疾病的转归。     

The role of aggression in range expansion and biological invasions

Traits that aid in the invasion process should exhibit a gradient across the expansion range in response to changing selection pressures. Aggression has been repeatedly associated with invasion success in many taxa, as it may help invaders to wrestle the resources from other species which enhances their success in a novel environment. However, aggression primarily al lows individuals to overcome conspecific rivals, providing advantages in competition over resources. Agonistic prowess could therefore increase fitness at both ends of the expansion gradient. Here we review the role of aggression in range expansion of in vasive species, and its potential role as a driver of range expansion. We analyze how these different mechanisms could affect trait variation in expanding and invasive populations. Specifically, we look at how aggression could help dilate the edges of a popula tion through niche competition, as well as lead to exclusion from the center （Le. areas of high population density） by the conspe cities. Both of these processes will result in a characteristic spatial distribution of phenotypes related to aggression that could provide insights into the ecological pressures and dynamics of expanding populations, potentially providing clues to their success as niche competitors and invasive species     

围手术期乳腺癌患者社会支持状态及相关因素的调查研究

目的:调查围手术期乳腺癌患者社会支持状态及其相关因素,分析影响围手术期乳腺癌患者的促进和阻碍因素,为提高围手术期乳腺癌患者社会支持状态提供理论基础。方法:自2012年1~6月对在哈尔滨医科大学附属第二医院普外八病房进行手术治疗的96例乳腺癌患者进行问卷调查,调查内容为自制调查问卷,主要包括患者的社会支持状态、焦虑及一般人口学资料。结果:围手术期乳腺癌患者社会支持得分为(69.49±7.43)分,状态焦虑得分为(41.61±12.01)分,特质焦虑得分为(41.07±11.81)分,Pearson相关分析结果显示,社会支持与特质焦虑呈负相关,一般人口学资料中社会支持的影响因素有家庭经济状况和教育程度。结论:围手术期乳腺癌患者社会支持处于高支持状态,经济状况较好、教育程度高的乳腺癌患者其社会支持水平较高,医护人员可以通过降低患者焦虑水平,提高其社会支持水平,以促进疾病的康复。     

Ecological predictors of extinction risks of endemic mammals of China

In this brief report, we analyzed ecological correlates of risk of extinction for mammals endemic to China using phylogenetic eigenvector methods to control for the effect of phylogenetic inertia. Extinction risks were based on the International Union for Conservation of Nature(IUCN) Red List and ecological explanatory attributes that include range size and climatic variables. When the effect of phylogenetic inertia were controlled, climate became the best predictor for quantifying and evaluating extinction risks of endemic mammals in China, accounting for 13% of the total variation. Range size seems to play a trivial role, explaining ~1% of total variation; however, when non-phylogenetic variation partitioning analysis was done, the role of range size then explained 7.4% of total variation. Consequently, phylogenetic inertia plays a substantial role in increasing the explanatory power of range size on the extinction risks of mammals endemic to China. Limitations of the present study are discussed, with a focus on under-represented sampling of endemic mammalian species.     

How to deal with neglected tropical diseases in the light of an African ethic

Many countries in Africa, and more generally those in the Global South with tropical areas, are plagued by illnesses that the wealthier parts of the world (mainly ‘the West’) neither suffer from nor put systematic effort into preventing, treating or curing. What does an ethic with a recognizably African pedigree entail for the ways various agents ought to respond to such neglected diseases? As many readers will know, a characteristically African ethic prescribes weighty duties to aid on the part of those in a position to do so, and it therefore entails that there should have been much more contribution from the Western, ‘developed’ world. However, what else does it prescribe, say, on the part of sub‐Saharan governments and the African Union, and are they in fact doing it? I particularly seek to answer these questions here, by using the 2013‐16 Ebola crisis in West Africa to illustrate what should have happened but what by and large did not.     

Ichnodiversity and ichnodisparity: significance and caveats

Ichnodiversity has been used as a proxy for environmental stress and stability in facies interpretations and to reconstruct evolutionary radiations and colonization histories in evolutionary palaeoecology. The three components of global diversity are exported from ecology and adapted for ichnology. Alpha ichnodiversity is used for palaeoenvironmental characterization, being assessed for individual facies. Beta ichnodiversity is commonly overlooked, although it may provide information about degree of similarity between ichnofaunas formed along environmental gradients. Gamma ichnodiversity may provide clues to detect ichnofossil provincialism. The concept of disparity may also prove to be significant in ichnological studies. Whereas ichnodiversity refers to ichnotaxonomic richness, ichnodisparity provides a measure of the variability of morphological plans in biogenic structures. Changes in global ichnodiversity do not necessarily parallel changes in ichnodisparity. For example, while the Cambrian explosion involved a dramatic increase in both, the Ordovician radiation essentially reflects an increase only in the former. Ichnodiversity and ichnodisparity should be used with caution because they are both affected by taphonomic processes. High diversity of superficial to shallow‐tier trace fossils may result from enhanced preservation due a poorly developed mixed layer, rather than a true reflection of ecosystem performance, as shown by underexploited infaunal ecospace after biotic crises (e.g. end‐Permian mass extinction).     

The 12th International Workshops on Opportunistic Protists (IWOP‐12)

The 12th International Workshops on Opportunistic Protists (IWOP‐12) was held in August 2012 in Tarrytown, New York. The objectives of the IWOP meetings are to: (1) serve as a forum for exchange of new information among active researchers concerning the basic biology, molecular genetics, immunology, biochemistry, pathogenesis, drug development, therapy, and epidemiology of these immunodeficiency‐associated pathogenic eukaryotic microorganisms that are seen in patients with AIDS and (2) foster the entry of new and young investigators into these underserved research areas. The IWOP meeting focuses on opportunistic protists, e.g. the free‐living amoebae, Pneumocystis, Cryptosporidium, Toxoplasma, the Microsporidia, and kinetoplastid flagellates. This conference represents the major conference that brings together research groups working on these opportunistic pathogens. Slow but steady progress is being achieved on understanding the biology of these pathogenic organisms, their involvement in disease causation in both immune‐deficient and immune‐competent hosts, and is providing critical insights into these emerging and reemerging pathogens. This IWOP meeting demonstrated the importance of newly developed genomic level information for many of these pathogens and how analysis of such large data sets is providing key insights into the basic biology of these organisms. A great concern is the loss of scientific expertise and diversity in the research community due to the ongoing decline in research funding. This loss of researchers is due to the small size of many of these research communities and a lack of appreciation by the larger scientific community concerning the state of art and challenges faced by researchers working on these organisms.     

Nematodes associated with Ips cembrae (Coleoptera: Curculionidae): comparison of generations,sexes and sampling methods

A study of nematodes associated with the large larch bark beetle Ips cembrae (Heer 1836) was carried out at three locations in the Czech Republic. The proportion of beetles infested by endoparasitic nematodes (representatives of genera Contortylenchus, Parasitylenchus, Cryptaphelenchus and Parasitorhabditis) ranged from 29.9 to 50.9%. Significant differences were determined in nematode infestation levels among locations, generations and sampling methods. No differences were found in infestation rates between males and females. The percentage of bark beetles with phoretic nematodes ranged from 18 to 42.9%. Phoretic nematodes directly found under elytra, on wings and between body segments of the bark beetles belong to the genus Micoletzkya. However, adults and juveniles of other two phoretic species Laimaphelenchus penardi and Bursaphelenchus sp. were found in the gallery frass of I. cembrae. Infestation by phoretic nematodes positively correlated with the presence of mites under elytra.     

Concordance of bacterial communities of two tick species and blood of their shared rodent host

High‐throughput sequencing is revealing that most macro‐organisms house diverse microbial communities. Of particular interest are disease vectors whose microbiome could potentially affect pathogen transmission and vector competence. We investigated bacterial community composition and diversity of the ticks Dermacentor variabilis (n = 68) and Ixodes scapularis (n = 15) and blood of their shared rodent host, Peromyscus leucopus (n = 45) to quantify bacterial diversity and concordance. The 16S rRNA gene was amplified from genomic DNA from field‐collected tick and rodent blood samples, and 454 pyrosequencing was used to elucidate their bacterial communities. After quality control, over 300 000 sequences were obtained and classified into 118 operational taxonomic units (OTUs, clustered at 97% similarity). Analysis of rarefied communities revealed that the most abundant OTUs were tick species‐specific endosymbionts, Francisella and Rickettsia, and the commonly flea‐associated bacterium Bartonella in rodent blood. An Arsenophonus and additional Francisella endosymbiont were also present in D. variabilis samples. Rickettsia was found in both tick species but not in rodent blood, suggesting that it is not transmitted during feeding. Bartonella was present in larvae and nymphs of both tick species, even those scored as unengorged. Relatively, few OTUs (e.g. Bartonella, Lactobacillus) were found in all sample types. Overall, bacterial communities from each sample type were significantly different and highly structured, independent of their dominant OTUs. Our results point to complex microbial assemblages inhabiting ticks and host blood including infectious agents, tick‐specific endosymbionts and environmental bacteria that could potentially affect arthropod‐vectored disease dynamics.     

Host‐associated genomic differentiation in congeneric butterflies: now you see it,now you do not

Ecotypic variation among populations may become associated with widespread genomic differentiation, but theory predicts that this should happen only under particular conditions of gene flow, selection and population size. In closely related species, we might expect the strength of host‐associated genomic differentiation (HAD) to be correlated with the degree of phenotypic differentiation in host‐adaptive traits. Using microsatellite and Amplified Fragment Length Polymorphism (AFLP) markers, and controlling for isolation by distance between populations, we sought HAD in two congeneric species of butterflies with different degrees of host plant specialization. Prior work on Euphydryas editha had shown strong interpopulation differentiation in host‐adapted traits, resulting in incipient reproductive isolation among host‐associated ecotypes. We show here that Euphydryas aurinia had much weaker host‐associated phenotypic differentiation. Contrary to our expectations, we detected HAD in Euphydryas aurinia, but not in E. editha. Even within an E. aurinia population that fed on both hosts, we found weak but significant sympatric HAD that persisted in samples taken 9 years apart. The finding of significantly stronger HAD in the system with less phenotypic differentiation may seem paradoxical. Our findings can be explained by multiple factors, ranging from differences in dispersal or effective population size, to spatial variation in genomic or phenotypic traits and to structure induced by past histories of host‐adapted populations. Other infrequently measured factors, such as differences in recombination rates, may also play a role. Our result adds to recent work as a further caution against assumptions of simple relationships between genomic and adaptive phenotypic differentiation.