青少年体育锻炼与心理幸福感的关系：实现型动机的调节作用*

为了考察青少年体育锻炼、快乐型和实现型动机与心理幸福感之间的关系，采用体育锻炼等级、快乐型和实现型动机、心理幸福感3个量表对455名中学生进行调查。结果发现：1）体育锻炼等级可正向预测青少年心理幸福感，锻炼量越大，青少年的心理幸福感水平越高；2）快乐型动机和实现型动机可正向预测青少年心理幸福感，且比体育锻炼量更具有预测力；3）实现型动机在体育锻炼与青少年心理幸福感之间起调节作用，而快乐型动机不起调节作用。结论：在提升心理幸福感路径中，青少年在体育锻炼中追求快乐型和实现型动机比提高锻炼量更加重要；当实现型动机处在较高水平，体育锻炼量才可更好地正向预测青少年心理幸福感。     

Neural responses to taxation and voluntary giving reveal motives for charitable donations

Civil societies function because people pay taxes and make charitable contributions to provide public goods. One possible motive for charitable contributions, called "pure altruism," is satisfied by increases in the public good no matter the source or intent. Another possible motive, "warm glow," is only fulfilled by an individual's own voluntary donations. Consistent with pure altruism, we find that even mandatory, tax-like transfers to a charity elicit neural activity in areas linked to reward processing. Moreover, neural responses to the charity's financial gains predict voluntary giving. However, consistent with warm glow, neural activity further increases when people make transfers voluntarily. Both pure altruism and warm-glow motives appear to determine the hedonic consequences of financial transfers to the public good.     

Effects of landscape corridors on seed dispersal by birds

Habitat fragmentation threatens biodiversity by disrupting dispersal. The mechanisms and consequences of this disruption are controversial, primarily because most organisms are difficult to track. We examined the effect of habitat corridors on long-distance dispersal of seeds by birds, and tested whether small-scale (<20 meters) movements of birds could be scaled up to predict dispersal of seeds across hundreds of meters in eight experimentally fragmented landscapes. A simulation model accurately predicted the observed pattern of seed rain and revealed that corridors functioned through edge-following behavior of birds. Our study shows how models based on easily observed behaviors can be scaled up to predict landscape-level processes.     

Pure reasoning in 12-month-old infants as probabilistic inference

Many organisms can predict future events from the statistics of past experience, but humans also excel at making predictions by pure reasoning: integrating multiple sources of information, guided by abstract knowledge, to form rational expectations about novel situations, never directly experienced. Here, we show that this reasoning is surprisingly rich, powerful, and coherent even in preverbal infants. When 12-month-old infants view complex displays of multiple moving objects, they form time-varying expectations about future events that are a systematic and rational function of several stimulus variables. Infants' looking times are consistent with a Bayesian ideal observer embodying abstract principles of object motion. The model explains infants' statistical expectations and classic qualitative findings about object cognition in younger babies, not originally viewed as probabilistic inferences.     

How we see ourselves and how we see others

People see themselves differently from how they see others. They are immersed in their own sensations, emotions, and cognitions at the same time that their experience of others is dominated by what can be observed externally. This basic asymmetry has broad consequences. It leads people to judge themselves and their own behavior differently from how they judge others and those others' behavior. Often, those differences produce disagreement and conflict. Understanding the psychological basis of those differences may help mitigate some of their negative effects.     

Developmental biology. Brain cells turning over a new leaf

New findings described on page 1754 offer the strongest evidence yet that certain cells can be steered onto new career paths even after they've become committed to a particular job. In the current work, researchers managed to coax rat oligodendrocyte precursor cells, which scientists thought were irreversibly committed to becoming neuronal handmaidens called oligodendrocytes or astrocytes, into becoming neurons. Because they ran several experiments to test the purity of their well-characterized cells, they say it is unlikely that the effect was due to undetected immature cells.     

Animal migration and infectious disease risk

Animal migrations are often spectacular, and migratory species harbor zoonotic pathogens of importance to humans. Animal migrations are expected to enhance the global spread of pathogens and facilitate cross-species transmission. This does happen, but new research has also shown that migration allows hosts to escape from infected habitats, reduces disease levels when infected animals do not migrate successfully, and may lead to the evolution of less-virulent pathogens. Migratory demands can also reduce immune function, with consequences for host susceptibility and mortality. Studies of pathogen dynamics in migratory species and how these will respond to global change are urgently needed to predict future disease risks for wildlife and humans alike.     

Extinction and ecosystem function in the marine benthos

Rapid changes in biodiversity are occurring globally, yet the ecological impacts of diversity loss are poorly understood. Here we use data from marine invertebrate communities to parameterize models that predict how extinctions will affect sediment bioturbation, a process vital to the persistence of aquatic communities. We show that species extinction is generally expected to reduce bioturbation, but the magnitude of reduction depends on how the functional traits of individual species covary with their risk of extinction. As a result, the particular cause of extinction and the order in which species are lost ultimately govern the ecosystem-level consequences of biodiversity loss.     

Effects of solar flares on the ionosphere of Mars

All planetary atmospheres respond to the enhanced x-rays and ultraviolet (UV) light emitted from the Sun during a flare. Yet only on Earth are observations so continuous that the consequences of these essentially unpredictable events can be measured reliably. Here, we report observations of solar flares, causing up to 200% enhancements to the ionosphere of Mars, as recorded by the Mars Global Surveyor in April 2001. Modeling the altitude dependence of these effects requires that relative enhancements in the soft x-ray fluxes far exceed those in the UV.     

Matriarchs as repositories of social knowledge in African elephants

Despite widespread interest in the evolution of social intelligence, little is known about how wild animals acquire and store information about social companions or whether individuals possessing enhanced social knowledge derive biological fitness benefits. Using playback experiments on African elephants (Loxodonta africana), we demonstrated that the possession of enhanced discriminatory abilities by the oldest individual in a group can influence the social knowledge of the group as a whole. These superior abilities for social discrimination may result in higher per capita reproductive success for female groups led by older individuals. Our findings imply that the removal of older, more experienced individuals, which are often targets for hunters because of their large size, could have serious consequences for endangered populations of advanced social mammals such as elephants and whales.     

Modeling effects of environmental change on wolf population dynamics, trait evolution, and life history

Environmental change has been observed to generate simultaneous responses in population dynamics, life history, gene frequencies, and morphology in a number of species. But how common are such eco-evolutionary responses to environmental change likely to be? Are they inevitable, or do they require a specific type of change? Can we accurately predict eco-evolutionary responses? We address these questions using theory and data from the study of Yellowstone wolves. We show that environmental change is expected to generate eco-evolutionary change, that changes in the average environment will affect wolves to a greater extent than changes in how variable it is, and that accurate prediction of the consequences of environmental change will probably prove elusive.     

A survey method for characterizing daily life experience: the day reconstruction method

The Day Reconstruction Method (DRM) assesses how people spend their time and how they experience the various activities and settings of their lives, combining features of time-budget measurement and experience sampling. Participants systematically reconstruct their activities and experiences of the preceding day with procedures designed to reduce recall biases. The DRM's utility is shown by documenting close correspondences between the DRM reports of 909 employed women and established results from experience sampling. An analysis of the hedonic treadmill shows the DRM's potential for well-being research.     

Fitness trade-offs and environmentally induced mutation buffering in isogenic C. elegans

Mutations often have consequences that vary across individuals. Here, we show that the stimulation of a stress response can reduce mutation penetrance in Caenorhabditis elegans. Moreover, this induced mutation buffering varies across isogenic individuals because of interindividual differences in stress signaling. This variation has important consequences in wild-type animals, producing some individuals with higher stress resistance but lower reproductive fitness and other individuals with lower stress resistance and higher reproductive fitness. This may be beneficial in an unpredictable environment, acting as a "bet-hedging" strategy to diversify risk. These results illustrate how transient environmental stimuli can induce protection against mutations, how environmental responses can underlie variable mutation buffering, and how a fitness trade-off may make variation in stress signaling advantageous.     

Neurobiology. Long-sought protein packages glutamate

Glutamate, one of two neurotransmitters that send the basic "stop" and "go" signals that most other neurotransmitters merely modulate, is called into action wherever rapid-fire excitatory signals are needed--say, for vision or learning. For decades, researchers have been looking for the protein that packages glutamate for express delivery to other neurons. On page 957, researchers report that they've found this elusive transporter, dubbed VGLUT1.     

虚拟社区中的互动对共创价值影响的实证研究

从资源整合的角度，分析了互动对虚拟社区共创价值的影响.在虚拟社区的背景下，通过文献研究提出了虚拟社区共创价值的定义，并结合焦点小组访谈定性研究提出了虚拟社区共创价值的维度构成，包括实用价值、享乐价值和顾客资产3个维度.同时通过结构方程模型实证研究验证了互动、资源整合、共创价值和顾客忠诚之间的影响关系.研究结果表明，顾客与平台服务人员的互动以及顾客与顾客的互动可以通过资源整合，促进实用价值、享乐价值和顾客资产的实现.实用价值、享乐价值、顾客资产均对顾客忠诚产生了显著的正向影响.     

ELECTRONIC OPTICS: Organic Lasers Promise New Lease on Light

Many of today's lasers are made from ceramic chips that require expensive clean-room facilities to manufacture, and their color palette is somewhat limited. Researchers have long pinned their hopes on organic materials, which are typically easier and cheaper to process. Now, on page 599, a team reports that they've devised the first electrically powered solid state organic laser, a step that could open the floodgates for novel lasers that are cheaper and that shine in colors inorganics can't match.     

浅议六安市旅游电子商务发展对策

旅游电子商务是一种新型商务模式.目前,六安旅游电子商务网站已经有几十家,发展十分迅速.但是,由于发展时间短,六安旅游电子商务发展中出现了一些问题.本文分析六安市旅游电子商务的现状,从信息化水平、政府行政推动力、旅游消费习惯、旅游网站质量、政策法规、人才等方面分析六安旅游电子商务存在的问题,最后提出六安旅游电子商务发展的几点对策.     

Predicting the growth of lettuce from soil infrared reflectance spectra: the potential for crop management

Precision Agriculture - How well could one predict the growth of a leafy crop from reflectance spectra from the soil and how might a grower manage the crop in the light of those predictions?...     

森林群落同期发生演替的预测模型及其应用

主要介绍森林群落发生同期演替时各种状态转移情况下进行植被种类的趋势预测 .主要针对演替过程中出现分段或非线性演替时如何预测出植被中的顶极树种种类 .其具体方法是通过吸收演替过程中各种状态下树种的先验分布和条件分布从而得到后验分布的信息处理办法预测出森林群落的演替结果     

The influence of social hierarchy on primate health

Dominance hierarchies occur in numerous social species, and rank within them can greatly influence the quality of life of an animal. In this review, I consider how rank can also influence physiology and health. I first consider whether it is high- or low-ranking animals that are most stressed in a dominance hierarchy; this turns out to vary as a function of the social organization in different species and populations. I then review how the stressful characteristics of social rank have adverse adrenocortical, cardiovascular, reproductive, immunological, and neurobiological consequences. Finally, I consider how these findings apply to the human realm of health, disease, and socioeconomic status.