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In many animal groups, coordinated activity is facilitated by the emergence of leaders and followers. Although the identity of leaders is to some extent predictable, most groups experience frequent changes of leadership. How do group members cope with such changes in their social role? Here, we compared the foraging behaviour of pairs of stickleback fish after a period of either (i) role reinforcement, which involved rewarding the shyer follower for following, and the bolder leader for leading, or (ii) role reversal, which involved rewarding the shyer follower for leading, and the bolder leader for following. We found that, irrespective of an individual''s temperament, its tendency to follow is malleable, whereas the tendency to initiate collective movement is much more resistant to change. As a consequence of this lack of flexibility in initiative, greater temperamental differences within a pair led to improved performance when typical roles were reinforced, but to impaired performance when typical roles were reversed.  相似文献   

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In this paper GC/MS-SCAN was used to identify the crude oil components that persist after bioremediation treatment of contaminated soil and the metabolites generated during this process. The soil was treated in bioreactors inoculated with an adapted bacterial population. In the first of two sets of conditions used, the water phase of the reactor was circulated continuously at a flow rate of 7 l day−1, and in the other case, it was circulated for a short period once a day to give the equivalent of 0.5 l day−1. Data showed that acyclic, n- and substituted alkanes C12 were still present after one year of remediation, while the majority of substituted derivatives of polycyclic and aromatic hydrocarbons could not be detected by GC/MS-SCAN analysis. The number of components identified was about one-half of that initially observed. After treatment the same number of components was detected at the top and bottom of the reactor in which the water phase was circulated continuously, whereas a smaller number of metabolites were observed at the top rather than at the bottom of the reactor with discontinuous circulation. The analysis has pointed to the importance of n-alkanes, their substituted derivatives and polycyclic aromatic hydrocarbons as the most significant pollutants.  相似文献   

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A Mullens 《CMAJ》1998,158(2):239-241
REFERENCE-BASED PRICING has had a major impact on medical practice in British Columbia. Anne Mullens discusses the new system''s first 2 years. She says physicians outside BC should pay attention, because RBP may be heading their way. It is set to land in Australia next month.  相似文献   

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Learning to lead     
Aschwanden C 《Cell》2006,125(3):407-409
A successful research career requires not only an aptitude for science but also the mastering of other skills including communication, management, and grant writing. A growing number of programs at universities and research institutes aim to teach these crucial skills to graduate students, postdoctoral fellows, and junior faculty.  相似文献   

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Many problems in pure and applied ecology require the quantification of above‐ and below‐ground microclimates. Here I describe a data set of hourly microclimates for the Australian continent, simulated from the years 1990 to 2017 across a grid of 1893 locations approx. 60 km apart. The data were generated with the NicheMapR microclimate model, driven by 0.05° gridded daily meteorological forcing data (air temperature, wind speed, humidity, cloud cover, rainfall), 0.025° elevation and 0.008° soil texture data. The above‐ground microclimate variables include horizontal plane solar radiation, solar zenith angle, sky temperature (from which down‐welling longwave radiation can be computed), air temperature, relative humidity and wind speed at 1 and 120 cm height, and snow depth. The below‐ground variables include soil temperature, pore humidity, soil moisture and soil water potential for 0, 2.5, 5, 10, 15, 20, 30, 50, 100 and 200 cm below‐ground. The computations are for four shade levels (0%, 50%, 70% and 90%). The data set can be used for a wide variety of applications, including the computation of heat and water budgets of organisms, the potential for vegetation growth, and the computation of stress and growth indices. The use of daily forcing data also allows assessments of the consequences of extreme events including heat waves. Example applications are provided for computing plant growth potential, grasshopper egg development, lizard body temperature and mammalian energy and water requirements.  相似文献   

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Introduction

Identification of patients who are in early stages of lupus is currently done through clinical evaluation and is not greatly facilitated by available diagnostic tests. Profiling for patient characteristics and antibody specificities that predict disease would enhance the ability of physicians to identify and treat early cases prior to onset of organ damaging illness.

Methods

A group of 22 patients with 4 or fewer diagnostic criteria for lupus were studied for changes in clinical and autoantibody profiles after a mean follow up period of 2.4 years. An array with more than 80 autoantigens was used to profile immunoglobulin G (IgG) and immunoglobulin M (IgM) autoantibodies. Correlations with clinical disease progression were examined.

Results

3 of the 22 patients (14%) added sufficient criteria during follow up to satisfy a diagnosis of systemic lupus erythematosus (SLE) or to acquire a diagnosis of SLE renal disease. Patients who progressed were all females and were younger than those who did not progress (P=0.00054). IgG but not IgM autoreactivity showed greater increases in the progressor group than in the non-progressor group (P=0.047). IgG specificities that were higher at baseline in progressors included proliferating cell nuclear antigen (PCNA), beta 2 microglobulin, C1q and hemocyanin (P<0.019). Progressors had significant increases in La/SSB and liver cytosol type 1 (LC1) IgG autoantibodies over the period of evaluation (P≤0.0072). A quantitative risk profile generated from baseline demographic and autoantibody variables yielded highly different scores for the progressor and non-progressor groups (P=1.38 × 10-7)

Conclusions

In addition to demographic features, autoantibody profiles using an expanded array of specificities were correlated with the risk of progressive disease in patients with lupus. These findings suggest the feasibility of developing a simple diagnostic that could be applied by nonspecialists to screen for lupus and permit effective triage for specialty care.  相似文献   

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While the limbic system theory continues to be part of common scientific parlance, its validity has been questioned on multiple grounds. Nonetheless, the issue of whether or not there exists a set of brain areas preferentially dedicated to emotional processing remains central within affective neuroscience. Recently, a widespread neural reference space for emotion which includes limbic as well as other regions was characterized in a large meta-analysis. As methodologically heterogeneous studies go into such meta-analyses, showing in an individual study in which all parameters are kept constant, the involvement of overlapping areas for various emotion conditions in keeping with the neural reference space for emotion, would serve as valuable confirmatory evidence. Here, using fMRI, 20 young adult men were scanned while viewing validated neutral and effective emotion-eliciting short film excerpts shown to quickly and specifically elicit disgust, amusement, or sexual arousal. Each emotion-specific run included, in random order, multiple neutral and emotion condition blocks. A stringent conjunction analysis revealed a large overlap across emotion conditions that fit remarkably well with the neural reference space for emotion. This overlap included symmetrical bilateral activation of the medial prefrontal cortex, the anterior cingulate, the temporo-occipital junction, the basal ganglia, the brainstem, the amygdala, the hippocampus, the thalamus, the subthalamic nucleus, the posterior hypothalamus, the cerebellum, as well as the frontal operculum extending towards the anterior insula. This study clearly confirms for the visual modality, that processing emotional stimuli leads to widespread increases in activation that cluster within relatively confined areas, regardless of valence.  相似文献   

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