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1.
Volleyball players need to sprint and change direction during a match. Lower-body power, often measured by jump tests, could contribute to faster movements. How different jumps relate to linear and change-of-direction (COD) speed has not been analyzed in Division I (DI) collegiate women’s volleyball players. Fifteen female volleyball players completed the vertical jump (VJ), two-step approach jump (AppJ), and standing broad jump (SBJ). Peak power and power-to-body mass ratio (P:BM) were derived from VJ and AppJ height; relative SBJ was derived from SBJ distance. Linear speed was measured via a 20-m sprint (0–10 and 0–20 m intervals); COD speed was measured using the pro-agility shuttle. Pearson’s correlations (p < 0.05) calculated relationships between the power variables, and speed tests. There were no significant relationships between the power variables and the 0–10 m sprint interval. Greater VJ height (r = -0.534) and P:BM (r = -0.557) related to a faster 0–20 m sprint interval. This be due to a greater emphasis on the stretch-shortening cycle to generate speed over 20 m. However, although a 20-m sprint may provide a measure of general athleticism, the distance may not be specific to volleyball. This was also indicated as the AppJ did not relate to any of the speed tests. Nonetheless, VJ height and P:BM, and SBJ distance and relative SBJ, all negatively correlated with the proagility shuttle (r = -0.548 to -0.729). DI women’s collegiate volleyball players could develop absolute and relative power in the vertical and horizontal planes to enhance COD speed.  相似文献   
2.
Bioinformatics tools have facilitated the reconstruction and analysis of cellular metabolism of various organisms based on information encoded in their genomes. Characterization of cellular metabolism is useful to understand the phenotypic capabilities of these organisms. It has been done quantitatively through the analysis of pathway operations. There are several in silico approaches for analyzing metabolic networks, including structural and stoichiometric analysis, metabolic flux analysis, metabolic control analysis, and several kinetic modeling based analyses. They can serve as a virtual laboratory to give insights into basic principles of cellular functions. This article summarizes the progress and advances in software and algorithm development for metabolic network analysis, along with their applications relevant to cellular physiology, and metabolic engineering with an emphasis on microbial strain optimization. Moreover, it provides a detailed comparative analysis of existing approaches under different categories.  相似文献   
3.
The 'system management approach' of biological weed control was applied in a small-scale field experiment with celeriac (root celery), intersown with an inbred line of the annual weed Senecio vulgaris L. The naturalized rust fungus Puccinia lagenophorae Cooke (Basidiomycetes: Uredinales), a common and widespread pathogen of S. vulgaris in Europe, was introduced into parts of the plots, and its impact on the competitive balance between the crop and weed in the presence and absence of an additional herbicide treatment was studied. Competition by S. vulgaris (at a realized density of only 50 plants/m2) during the first 10 weeks of growth was substantial, reducing the fresh weight of the celeriac bulbs by 28%. The epidemic spread of the rust fungus was relatively fast, and the time to infection was similar to that in full-area applications. Inoculation with the rust fungus strongly reduced crop losses due to competition with S. vulgaris . The fresh weight of the celeriac bulbs in plots with both S. vulgaris and the fungus was not statistically diVerent from the celeriac yield in plots without S. vulgaris . This eVect was mainly the result of the reduced biomass of S. vulgaris , and not reduced survival. Infected plants may, therefore, still contribute to soil cover and may help to suppress later germinating weed species. Older plant stages were found to be infected earlier than younger stages. No significant interactions were observed between the eVects of the fungal infection and a low-dose application of the herbicide chlorbromuron on weed performance. Basic studies necessary to develop the system management approach further are discussed.  相似文献   
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1. When using benthic macroinvertebrate communities for bioassessment, temporal variation may influence judgement as to whether or not a site is degraded.
2. In a survey of sixteen reference and sixteen test sites in the upper Thames River catchment area (UTRCA) in south-western Ontario, Canada, consistent differences between summer and winter samples were found for taxon richness (increase; P = 0.06) and the Family Biotic Index (decrease; P = 0.11). A bioassessment based on these results would indicate better water quality in the same streams in winter relative to summer. No consistent pattern of seasonal difference was detected for Simpson's Diversity and Equitability, or percentage Dominant Taxon.
3. The Reference Condition Approach to bioassessment uses predictive modelling to explain variation in reference communities with the environmental conditions at these sites as predictors. The community at a test site is compared with that predicted by the model. Several predictive models were constructed using simple geographic and habitat characteristics (i.e. catchment area, distance to source, stream width, substrate and habitat diversity) as predictors. By including season of sampling in the models, we increased their predictive power and the ability of the bioassessment to detect degradation. The best results were achieved when separate predictive models were built for each sampling season.  相似文献   
6.
Systems’ welfare evaluation, including behavioural testing, is becoming increasingly popular in farm animal assurance schemes. The aims of this study were to investigate whether fairly short-term exposure to gestation housing systems, which varied in physical, environmental and human-input factors, influenced behavioural and physiological measures during a human approach test—often used to identify problems in human–animal interactions. Twenty-four Large White×Landrace gilts were initially subjected to identical human contact and daily husbandry. Forty-two days after service, the gilts were randomly assigned to either an indoor housing system (n=16) or an outdoor housing system (n=8), which differed physically and in the amount of human contact and daily husbandry. The indoor system used an electronic sow feeder (ESF), was more space-limited and thermally-controlled and had human contact centered on cleaning out. The outdoor system was more extensive, had much greater space accessible, was not thermally-controlled and had human contact that centered around feeding. The human approach test was carried out on all gilts 30–44 days after entry to the gestation system. At testing, each individual was fitted with heart rate monitor and then moved into a test arena. After 2 min an unfamiliar human entered the pen and stood motionless for 3 min against one wall and then approached the gilt and touched her snout. Throughout the experimental period, behaviour and sound within the test arena were recorded continuously. During the 2 min familiarisation period, outdoor gilts had lower heart rates (108.2 bpm versus 123.7 bpm, P<0.05) and tended to perform fewer short vocalisations (0.5 calls per min versus 3.4 calls per min, P<0.1). Outdoor-housed gilts also carried out less locomotor behaviour (2.2 sections crossed versus 4.0 sections crossed, P<0.05) and tended to perform fewer short (1.4 calls per min versus 5.0 calls per min, P<0.1) and long vocalisations (0.2 calls per min versus 1.8 calls per min, P<0.1) over the 3 min test period. Outdoor gilts tended to be slower to approach within 0.5 m of the human (69.9 s versus 19.3 s, P<0.1) but they then took less extra time to make physical contact (3.3 s versus 52.7 s, P<0.1). Mean heart rate was significantly lower in outdoor sows over the whole 3 min period (99.5 bpm versus 115.5 bpm, P<0.05). The results demonstrate that short-term exposure to different housing systems did influence behavioural and physiological measures during a standard human approach test and thus, systems differences should be taken into account before making judgements about the human–animal relationship on any commercial farm, based on results of behavioural tests of this type.  相似文献   
7.
Radiofrequency ablation of Cavotricuspid Isthmus-dependent Atrial Flutter (CTI AFL), a usual and safe therapeutic procedure in interventional electrophysiology with a high success rate, aiming to induce permanent block of conduction over CTI, is normally performed via the femoral access, which allows practical access to the CTI through the inferior vena cava (IVC). In rare cases of obstruction of IVC, ablation of CTI can be performed only through the superior vena cava (SVC) access. We present a case of typical atrial flutter that was ablated through the right subclavian/jugular veins because of iatrogenic obstruction of the IVC due to a previously implanted thrombus filter. Furthermore we discuss about how we resolved access-related problems of instability during catheter ablation on CTI.  相似文献   
8.
砷还原菌群对砷的还原作用及菌群的多样性分析   总被引:1,自引:0,他引:1  
从砷污染土壤中富集砷抗性细菌,在厌氧环境中进行培养,观察其对砷的还原能力。结果表明:在21 h之内,As(V)就被完全还原为As(Ⅲ);培养72 h后,培养基中出现黄色沉淀,采用X射线衍射分析(XRD)和扫描电镜-能谱分析(SEM-EDS)技术对沉淀进行分析表明,沉淀主要是以3种晶型存在的硫化砷(AsS);培养150 h后,大约有65%的As以上述沉淀的方式从溶液中移除。此外,本文还采用了构建16S rDNA文库的方式对该体系中的微生物种群进行分析,利用RFLP技术对16S rDNA片段进行分型,共得到72个操作单元类型(OTU),其中6个OTU占了库容的51%,从这6个OTU中各选取1个克隆进行测序,结果表明,富集到的砷还原细菌属于喜热菌属(Caloramator)、梭菌属(Clostridium)和杆菌属(Bacillus)。  相似文献   
9.
Because chickens are highly social animals, live conspecifics are often used to provide an incentive or goal in studies of gait, sociality or fear that require the bird to traverse a runway. However, the variable behaviour of the stimulus birds can influence the approach/avoidance responses of the test birds and thereby confound the results. Because chickens modify their behaviour readily and appropriately to a variety of video images, including social stimuli, we asked if video playback might represent easily controllable and standardized alternatives to live birds. Female ISA Brown chicks were housed in groups of eight and then exposed to a blank illuminated television for 10 min per day from 2 to 7 days of age. At 8 or 9 days of age they were placed individually in the start box of a 1.6 m long runway and we recorded their responses to a monitor displaying selected video images that was situated in the goal box at the opposite end of the runway. In Experiment 1 chicks approached a monitor playing the video image and soundtrack of feeding chicks significantly sooner than one of a goal box with the food dish and background noise. In Experiment 2, chicks were exposed to the same video of feeding conspecifics with or without the associated sounds or to a video of the goal box with or without the chick soundtrack. Both the videos of other chicks elicited faster approach than did those of the goal box and the sound and silent versions were equally attractive. Adding the soundtrack of feeding chicks to the goal-box video failed to increase its attractiveness. The present results suggest that chicks are attracted towards televised images of other chicks. They also indicate that the visual and auditory components of the video stimuli did not exert additive effects and that approach reflected attraction to the visual image. Collectively, our findings suggest that video playback of selected social stimuli, such as feeding conspecifics, could be a valuable tool in tests requiring voluntary locomotion along a predetermined path.  相似文献   
10.
Aquatic ecosystems can be chronically stressed by multiple environmental factors which originate from a variety of point and non-point sources. In addition, these stressors may vary both spatially and temporally, and, combined with synergestic and cumulative interactions of these stressors, complicate the interpretation and evaluation of stress responses in organisms. To help identify and differentiate between sources of anthropogenic stressors in aquatic systems, a diagnostic approach based on exposure-response profiles in sentinel organisms was developed from the known effects of various anthropogenic activities on biological systems. To generate these exposure-effects profiles, biomarkers of exposure were plotted against bioindicators of corresponding effects for several major anthropogenic activities including petrochemical, pulp and paper, domestic sewage, mining operations, land-development, and agricultural activities. Biomarkers of exposure to environmental stressors varied widely depending on the type of anthropogenic activity involved. Bioindicator effects, however, including histopathological lesions, bioenergetic status, growth, reproductive impairment, and community-level endpoints were similar among several of the major anthropogenic activities because responses at these higher levels are less specific to stressors than are biomarkers. This approach appears useful for helping to identify and diagnose sources of stress in environments impacted by multiple stressors. By identifying the types and sources of environmental stressors impacting key components of biological systems, aquatic ecosystems can be more effectively protected, regulated, and managed to help improve and maintain environmental quality and ecosystem fitness.  相似文献   
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