853 resultados para 1094
Resumo:
Ten Canadian expert rowing coaches and 10 Canadian elite rowers were interviewed regarding their perceptions of effective coaching behaviors. The questions of the interview guide focused on coaches' behaviors in training, competition, and organization settings. Qualitative data analyses revealed seven behaviors elicited by coaches and athletes. Effective coaching behaviors perceived as important by both athletes and coaches were; 1) plan proactively, 2)create a positive training environment, 3)facilitate goal setting, 4)build athletes' confidence, 5) teach skills effectively, 6)recognize individual differences, and 7)establish a positive rapport with each athlete.
Resumo:
Introduction and aim Earthworms are an important test organisms used in several standard ecotoxicological tests (e.g. ISO, 2008, 2012; OECD, 2004, 1094) and they are also model organisms to test soil structure and permeability, as well as for important soil services as the degradation organic matter. Although histopathological changes have been demonstrated to be good biomarkers to assess the exposure of these animals to different physical and chemical stress agents, studies with clear and high quality images describing normal tissue conditions are scarce in the literature, so the aim of this work was to better characterize this biological model. Material and Methods Eight adult earthworms exposed to an artificial standard soil (OECD, 2004) for 28 days, were extracted and placed in a plastic box to depurate their gut content, fixed in 10% neutral-buffered formalin and processed for routine histopathological diagnosis. Results and discussion Satisfactory histological sections were obtained. Some difficulties were faced related with microtome sectioning, resulting in artefacts, namely lines across sections produced by a nick in the cutting edge of the microtome knife cutting tear, motivated by the presence of sand and other solid particles that persisted in the gut of earthworms. Nevertheless, it was possible to obtain representative figures from different earthworm sections. Conclusion Routine histological technique was effective for obtaining satisfactory histological sections and the knowledge of the histology of earthworms could be very useful for future application in environmental studies, using this biological model.
Resumo:
Comparison of daily and diel variability of chlorophyll-a concentration at three long-term stations in meso- and eutrophic regions indicates that their values are similar. Daily patterns of deviation in chlorophyll concentration in small and large phytoplankton fraction from average daily values are presented. In conformity with a hypothesis of daily removal rhythms correlated with changes in diel light-dark periods, it was concluded that the mesotrophic region during the dark period is characterized by predominance of grazing on large phytoplankton in the upper layers and accumulation of detritus from cell fragments in the lower layer, while during the light period smaller phytoplankton predominantly grazed. The eutrophic region is characterized by predominance of grazing on small phytoplankton fraction in the upper layers during the dark period and settling out of fecal pellets containing chlorophyll into deeper depths; but during the light period, large phytoplankton predominantly grazed throughout the whole water layer.
Resumo:
We present a 5.3-Myr stack (the ''LR04'' stack) of benthic d18O records from 57 globally distributed sites aligned by an automated graphic correlation algorithm. This is the first benthic delta18O stack composed of more than three records to extend beyond 850 ka, and we use its improved signal quality to identify 24 new marine isotope stages in the early Pliocene. We also present a new LR04 age model for the Pliocene-Pleistocene derived from tuning the delta18O stack to a simple ice model based on 21 June insolation at 65 N. Stacked sedimentation rates provide additional age model constraints to prevent overtuning. Despite a conservative tuning strategy, the LR04 benthic stack exhibits significant coherency with insolation in the obliquity band throughout the entire 5.3 Myr and in the precession band for more than half of the record. The LR04 stack contains significantly more variance in benthic delta18O than previously published stacks of the late Pleistocene as the result of higher resolution records, a better alignment technique, and a greater percentage of records from the Atlantic. Finally, the relative phases of the stack's 41- and 23-kyr components suggest that the precession component of delta18O from 2.7-1.6 Ma is primarily a deep-water temperature signal and that the phase of d18O precession response changed suddenly at 1.6 Ma.