Eating Behaviors and Supplement Use of College Upperclassmen Athletes Versus Lowerclassmen Athletes

Background: Past studies have shown that optimal nutrition can enhance physical activity, athletic performance, and recovery from exercise. It is important for college athletes to incorporate positive eating behaviors into their daily lives, such as consuming breakfast, eating frequently throughout the day, and not skipping meals in order to maintain energy levels and reach their sports performance potential. Objective: The purpose of this study was to compare the eating behaviors and dietary supplement use of underclassmen and upperclassmen student athletes at Georgia State University. Methods: Underclassmen (freshmen, sophomores) and upperclassmen (juniors, seniors, fifth-year seniors) athletes (n=255) completed a nutrition screening questionnaire. Chi-square analysis was used to assess group differences in eating behaviors and supplement use. Results: Underclassmen student athletes were significantly more likely than upperclassmen to consume breakfast most days of the week (p=0.008). The underclassmen also reported significantly more eating occasions during the day than upperclassmen (p=0.012). The majority of both groups reported skipping meals, and breakfast was the meal most frequently missed. No significant difference was found for supplement use between the classes, but over half of the underclassmen (53%) and upperclassmen (59%) have taken or currently take protein supplements. Conclusions: The underclassmen athletes at Georgia State University displayed better eating habits than the upperclassmen, but dietary supplement use was the same in both groups. The findings indicate that all student athletes at the university could benefit from learning about ways to improve their eating habits and obtain peak performance through diet, without supplements

Are Proxima and Alpha Centauri Gravitationally Bound?

Using the most recent kinematic and radial velocity data in the literature, we calculate the binding energy of Proxima Centauri relative to the center of mass of the Alpha Centauri system. When we adopt the centroids of the observed data, we find that the three stars constitute a bound system, albeit with a semi-major axis that is on order the same size as Alpha Centauri AB's Hill radius in the galactic potential. We carry out a Monte Carlo simulation under the assumption that the errors in the observed quantities are uncorrelated. In this simulation, 44% of the trial systems are bound, and systems on the 1-3 sigma tail of the radial velocity distribution can have Proxima currently located near the apastron position of its orbit. Our analysis shows that a further, very significant improvement in the characterization of the system can be gained by obtaining a more accurate measurement of the radial velocity of Proxima Centauri.Comment: 10 pages total, 4 pages of text, 1 page of references, 3 figures, and 2 tables This article will be published in The Astronomical Journa

O processo de produção de vitrais sob a ótica da tradição

It's impossible to make a discussion about stained glass without bringing up the concepts of tradition. The manual process of stained glass manufacture is based on the knowledge transmitted from generation to generation, and this process has changed just a little until today. The overlaps of glasses colored or not in the plumb gutter define the production of stained glass and this manufacture process is a well-known process since the middle age. This kind of artisanal technique would not remain to date if there were no memory and tradition to use this practice. Such practice originates from the hierarchic relationship of masters and apprentices. Concentrating on the vision that the memory and tradition are fonts of a cultural and patrimonial identity, this work studied the historical, artisanal and technological process of stained glass manufacture and their close link with the tradition and the knowledge. We also reflected about innovation and continuity of the process of stained glass production.Não se pode falar em vitral sem responder a aspectos de conceitos de tradição. O processo de trabalho manual que envolve a produção vitral baseia-se na memória contida no conhecimento transmitido de geração a geração, que a pratica de atelier pouco mudou, visto que a fabricação do vitral está basicamente vinculada ao seu processo de obtenção. A justaposição de vidros, coloridos ou não, e uma calha de chumbo é que define a produção do vitral e esse processo se encontra amadurecido desde a Idade Média. Esta arte não chegaria aos dias de hoje se não houvesse a memória e a tradição desta prática artesanal, originária de uma hierarquia formada por mestres e aprendizes. Focado na visão de que a memória e a tradição são fontes de identidade cultural e patrimonial, no presente trabalho, fez-se um estudo sobre o processo histórico, artesanal e tecnológico de produção de vitrais e seu estreito vínculo com o saber e a tradição. Refletiu-se, também, sobre a tradição e os aspectos de inovação e continuidade do processo de produção de vitrais

Local threshold field for dendritic instability in superconducting MgB2 films

Using magneto-optical imaging the phenomenon of dendritic flux penetration in superconducting films was studied. Flux dendrites were abruptly formed in a 300 nm thick film of MgB2 by applying a perpendicular magnetic field. Detailed measurements of flux density distributions show that there exists a local threshold field controlling the nucleation and termination of the dendritic growth. At 4 K the local threshold field is close to 12 mT in this sample, where the critical current density is 10^7 A/cm^2. The dendritic instability in thin films is believed to be of thermo-magnetic origin, but the existence of a local threshold field, and its small value are features that distinctly contrast the thermo-magnetic instability (flux jumps) in bulk superconductors.Comment: 6 pages, 6 figures, submitted to Phys. Rev.

Local biases drive, but do not determine, the perception of illusory trajectories

When a dot moves horizontally across a set of tilted lines of alternating orientations, the dot appears to be moving up and down along its trajectory. This perceptual phenomenon, known as the slalom illusion, reveals a mismatch between the veridical motion signals and the subjective percept of the motion trajectory, which has not been comprehensively explained. In the present study, we investigated the empirical boundaries of the slalom illusion using psychophysical methods. The phenomenon was found to occur both under conditions of smooth pursuit eye movements and constant fixation, and to be consistently amplified by intermittently occluding the dot trajectory. When the motion direction of the dot was not constant, however, the stimulus display did not elicit the expected illusory percept. These findings confirm that a local bias towards perpendicularity at the intersection points between the dot trajectory and the tilted lines cause the illusion, but also highlight that higher-level cortical processes are involved in interpreting and amplifying the biased local motion signals into a global illusion of trajectory perception

Local biases drive, but do not determine, the perception of illusory trajectories

When a dot moves horizontally across a set of tilted lines of alternating orientations, the dot appears to be moving up and down along its trajectory. This perceptual phenomenon, known as the slalom illusion, reveals a mismatch between the veridical motion signals and the subjective percept of the motion trajectory, which has not been comprehensively explained. In the present study, we investigated the empirical boundaries of the slalom illusion using psychophysical methods. The phenomenon was found to occur both under conditions of smooth pursuit eye movements and constant fixation, and to be consistently amplified by intermittently occluding the dot trajectory. When the motion direction of the dot was not constant, however, the stimulus display did not elicit the expected illusory percept. These findings confirm that a local bias towards perpendicularity at the intersection points between the dot trajectory and the tilted lines cause the illusion, but also highlight that higher-level cortical processes are involved in interpreting and amplifying the biased local motion signals into a global illusion of trajectory perception

Phone-based audience response system as an adjunct in orthodontic teaching of undergraduate dental students: a cross-over randomised controlled trial

Background: The advent of electronic teaching facilities improves tutor-student communication. This study aims to explore the effectiveness of Phone-Based Audience Response System (PB-ARS), as an adjunctive pedagogy tool to enhance the retention of orthodontic information by dental students; and to explore the students’ perception of PB-ARS. Methods: This cross-over clustered randomised control trial included 34 males who were in the final year of their undergraduate dental training. Participants were allocated to one of two event groups (G1 and G2) using computer-generated randomisation. Both groups simultaneously attended two different traditional lectures (L 1 and L2) a week apart. During L1, PB-ARS was used as an adjunct to conventional presentation to teach G1 participants, (PB-ARS group) while G2’s participants acted as a control group (CG), and were taught using a traditional presentation. In the second week (L2), the interventions were crossed-over. Participants from both groups completed pre- and post-lecture multiple-choice questionnaires (MCQ) to assess their short-term retention of information. Their performance in the final MCQ exam (10 weeks following L2) was tracked to assess the long-term retention of the information. Participants also completed post-lecture questionnaires to evaluate their perceptions. Results: Twenty-nine and 31 participants from the CG and PB-ARS group completed this trial, respectively. Although 87.5% of students in the PB-ARS group showed an improvement in their immediate post-lecture scores compared with 79.3% for the CG, it was statistically insignificant (p = 0.465). Similarly, the intervention showed an insignificant effect on the long-term retention of the knowledge (p = 0.560). There was a mildly but favourable attitude of students towards the use of PB-ARS. However, the difference in the overall level of satisfaction between both groups was statistically insignificant (p = 0.183). Conclusion: PB-ARS has a minimal and insignificant effect on the short- and long-term retention of orthodontic knowledge by male undergraduate dental students. PB-ARS was the preferred adjunct tool to conventional classroom teaching. Due to the limitations of this trial, a long-term randomised controlled trial with a larger sample size is recommended