A completely general three-dimensional dynamic model is presented for the motion of basketball shots that may contact the rim, the backboard, the bridge between the rim and board, and possibly the board and the bridge simultaneously. Non-linear ordinary differential equations with six degrees of freedom describe the ball angular velocity and ball centre position. The model includes radial ball compliance and damping and contains five sub-models: purely gravitational flight, and ball-rim, ball-bridge, ball-board, and ball-bridge-board contact. Each contact sub-model has both slipping and non-slipping motions. Switching between the sub-models depends on the reaction force at, and velocity of, the contact point. Although the model can be used to study shots from any point on the court, we here use it to study the sets of free throw release angle, velocity, angular velocity, and lateral deviation angle that result in success (capture), as well as underhand free throws and those using an under-inflated ball. Free throw shots with larger backspin, lower inflation pressures, and underhand release conditions are shown to result in larger capture percentages. 相似文献
In the current experiment, we examined optimal focus for novices during a movement sequence in which performance was measured on accurate movement form/technique. A novel gymnastics routine was practiced under either an internal skill-relevant, internal skill-irrelevant, external, or no attention focus. Retention and transfer tests were then completed. During acquisition, adopting an internal irrelevant focus significantly improved performance, whereas an external focus degraded performance. There were no significant group differences in the retention and transfer tests. This suggests that learning of movement form/technique did not benefit from a specific focus of attention. The results are interpreted via an attentional capacity viewpoint and the notion that form tasks do not always contain obvious movement effects central to common coding and the constrained action hypothesis. 相似文献
Constructing explanations of scientific concepts is one of the most frequent strategies used in the science classroom and is a high-leverage teaching practice. This study analysed the explanations provided by student teachers in STEM areas from a socio-materiality perspective focused on verbal and nonverbal language and representations. The study was conducted in a hybrid research format by scholars and a preservice teacher. First, the study compared the representational elements used by 86 student teachers to construct explanations about various concepts in a roleplay setting. Next, a positioning analysis was done by a preservice teacher, to a selection of five of these explanations focused on the concept of “force”. The positioning analysis highlighted the embedded voices in the construction of explanations, with a focus on the intersection between science and language. The results showed that the student teachers created explanations as static artefacts, mainly using examples, graphs and images to clarify the concepts. The voices of learners and scientists were mostly absent from the explanations, which led to the presentation of explanations in STEM areas as finished and unquestionable artefacts, with references neither to nature nor to the history of science. We reflect on the meanings attributed to learning to be a practitioner in the context of interconnecting science and language through explanations, as a process of meaning (re)production within the classroom. Implications for teacher education are discussed in order to enhance student teachers’ awareness about constructing knowledge by enacting explanations in the science classroom.
Peer-teaching is widely established in anatomy teaching and offers well-described advantages. Nevertheless, at Ulm University, Germany, a reduction in the number of peer teacher applicants for the dissection course was observed. This study examined factors related to the attractiveness of a position as a peer teacher for Generation Z students. Participants of the gross anatomy course were asked to evaluate factors influencing the attractiveness of a peer teacher position using a six-point Likert scale. Additionally, open-ended questions were analyzed qualitatively. Sex-specific subgroup analysis was performed comparing students of low and high motivation to apply for a tutorship. Of the 374 students who participated in this study (response rate 53%), 38% stated that they were intending to apply as peer teachers. Data indicated that students displayed intrinsic motivation to apply for a tutorship because of the opportunity to improve their anatomy knowledge and/or their pleasure in teaching. In contrast, extrinsic factors like remuneration of the tutorship and its relevance for their curriculum vitae were least important. Anatomy educators underestimated the demotivating factor of the workload associated with the tutorship and encouraged students less frequently to apply than peer teachers. Only minor sex-specific differences could be identified. Nevertheless, female students were encouraged less frequently to apply than their male peers. In summary, Generation Z students apply as peer teachers because they are enthusiastic about the task. To motivate students to commit to extracurricular activities like a tutorship, anatomy educators should actively encourage students—particularly females—more frequently to apply. 相似文献
A standardized procedure was developed for eliciting those details of a library's service policies that are important to its users and for recording the data by checking appropriate categories on a form. This inventory procedure covers the entire spectrum of user services and accommodates a wide range of policies. The inventory was originally designed for use by trained interviewers in largescale surveys of academic medical libraries. However, it is also suitable for other kinds of libraries, and the Interview Guide and Checklist can be used for a self-survey by library staff. In addition to survey use, the inventory has a variety of educational, administrative, managerial, and research applications. A method for weighting the categorical inventory data to reflect the relative desirability of different policies makes it possible to calculate scores indicating how a library's policies compare with those of an "optimal" library. An analogous inventory of the services a library provides to other libraries was developed for surveying major backup resources in the medical library system. 相似文献
Organic acid disorders are inherited metabolic disorders in which organic acids accumulate in tissues and biological fluids
of affected individuals. Classical organic acidurias include methylmalonic aciduria, propionic aciduria, isovaleric aciduria
and maple syrup urine disease (MSUD). They are considered the most frequent metabolic disorders among severely ill children.
Patients frequently present with acute symptoms early in life. 420 cases clinically suspected to have organic aciduria, with
upper age limit of 12 years for a 2-year period (January 2007–December 2008) were enrolled into this study. Metabolic acidosis
and neurological symptoms were the most common signs. Screening tests and thin layer chromatography were done for detection
of organic acidurias. Identification and quantitation of organic acids in urine and quantification of amino acids in blood
were done by high performance liquid chromatography. Out of 420 patients, 45 patients (10.7%) were found to have organic acidurias.
15 cases of methylmalonic aciduria, 16 cases of propionic aciduria, 13 cases of MSUD, and one case of isovaleric aciduria
were diagnosed. Results demonstrate the importance of testing for organic acidurias. Since organic aciduria may cause irreversible
brain damage if not treated, we recommend selective screening amongst severely ill children despite implied extra costs. 相似文献