Modelling and simulation of a biomimetic underwater vehicle

This paper describes work carried out at the University of Glasgow investigating biomimetic fish-like propulsion systems for underwater vehicles. The development of a simple mathematical model is described for a biomimetic fish like vehicle which utilizes a tendon drive propulsion system. This model is then compared with a model of a vehicle of similar size but with a propeller for main propulsion. Simulation results for both models are shown and compared

The psychological benefits of Special Olympic involvement

Section A is a review of the current literature on sports involvement with respect to people with learning disabilities. It begins by describing the health status of people with learning disabilities and provides a context of sport and wellbeing in the general population. It continues by describing four reviews of the literature exploring people with learning disabilities with respect to sports involvement. This section ends with a description of the Special Olympics research and suggests future research needs in this area. Section B describes a quantitative cross-sectional study comparing two groups of sports active and non-active people with learning disabilities using several psychological measures. Objectives. There is evidence that people with learning disabilities have poorer mental and physical wellbeing compared with that of the wider population. The aim of this study was to explore whether a group of people with learning disabilities involved in sport differed in terms of psychological well-being compared with a group not involved in sport. Design. A cross sectional design was employed comparing two groups, sports active and non-active on the variables: Self-esteem, quality of life, stress levels and social networks. Methods. Seventy four participants were recruited across South East England. They completed a number of psychological measures. Results. Analysis revealed that self-esteem, quality of life, social networks and stress were all significantly correlated with Special Olympics involvement. A logistic regression analysis was used to explore whether scores on these variables were able to predict sport membership. Self-esteem was found to be a high predictor of group membership, those in the Special Olympics having higher self-esteem. Conclusions. The findings provide further evidence of a positive association between sport involvement and increased psychological wellbeing. The implications of these findings for theory and future research into the relationship between sport and psychological wellbeing within the learning disabled population is considered. Section C is a critical appraisal of the quantitative study that considers four aspects: research skills; amendments to the study if it were replicated; how the study may have influenced clinical practice; and finally, further research and methods relating to this area

Pre-Big Bang Scenario on Self-T-Dual Bouncing Branes

We consider a new class of 5-dimensional dilatonic actions which are invariant under T-duality transformations along three compact coordinates, provided that an appropriate potential is chosen. We show that the invariance remains when we add a boundary term corresponding to a moving 3-brane, and we study the effects of the T-duality symmetry on the brane cosmological equations. We find that T-duality transformations in the bulk induce scale factor duality on the brane, together with a change of sign of the pressure of the brane cosmological matter. However, in a remarkable analogy with the Pre-Big Bang scenario, the cosmological equations are unchanged. Finally, we propose a model where the dual phases are connected through a scattering of the brane induced by an effective potential. We show how this model can realise a smooth, non-singular transition between a pre-Big Bang superinflationary Universe and a post-Big Bang accelerating Universe.Comment: 18 pages, minor typos corrected, Sec. 2 expanded with more details on the self-T-dual background, Sec.4 and 5 revised accordingly. Version to appear on JCA

Constraints on Neutron Star Crusts From Oscillations in Giant Flares

We show that the fundamental seismic shear mode, observed as a quasi-periodic oscillation in giant flares emitted by highly-magnetized neutron stars, is particularly sensitive to the nuclear physics of the crust. The identification of an oscillation at ~ 30 Hz as the fundamental crustal shear mode requires a nuclear symmetry energy that depends very weakly on density near saturation. If the nuclear symmetry energy varies more strongly with density, then lower frequency oscillations, previously identified as torsional Alfven modes of the fluid core, could instead be associated with the crust. If this is the case, then future observations of giant flares should detect oscillations at around 18 Hz. An accurate measurement of the neutron skin thickness of lead will also constrain the frequencies predicted by the model.Comment: 5 pages, 3 figures; Version to appear in Phys. Rev. Let

Immediate versus water-storage performance of Class V flowable composite restoratives

Objectives The aims of this investigation were to clarify the effects of 24 h water-storage and finishing time on mechanical properties and marginal adaptation to a Class V cavity of eight modern flowable resin-composites. Methods Eight flowable composites, plus two controls (one microfilled and one hybrid composite), were investigated with specimen sub-groups (n = 10) for each property measured. The principal series of experiments was conducted in model Class V cavities with interfacial polishing either immediately (3 min) after setting or after 24 h water-storage. After the finishing procedure, each tooth was sectioned in a buccolingual direction through the center of the restoration, and the presence or absence of marginal-gaps was measured (and then summed for each cavity) at 14 points (each 0.5 mm apart) along the cavity restoration interface (n = 10 per group; total points measured = 140). The shear bond-strengths to enamel and to dentin, and flexural strengths and moduli data were also measured at 3 min and after 24 h water-storage. Results For all flowable composites, polished immediately after setting, 14–30 summed gaps were observed (controls: 64 and 42). For specimens polished after 24 h, a significantly (p &#60; 0.05) reduced number of 8–17 summed gaps occurred for only 3 flowable composites; whereas for 5 flowable composites there were non-significantly-different (p &#62; 0.05) numbers (11–17) of summed gaps (controls: 28 and 22). After 24 h storage, shear bond-strengths to enamel and to dentin, flexural strengths and moduli increased highly significantly (p &#60; 0.001) for all materials, except Silux Plus. Significance A post-cure interval of 24 h resulted in enhanced mechanical and adhesive properties of flowable dental composites. In a minority of cases there was also a reduced incidence of marginal-gap formation. However the latter effect may be partly attributed to 24 h delayed polishing, even though such a delay is not usual clinical practice.</p

Alien Registration- Watts, Hazel C. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/21758/thumbnail.jp

Program, Policy, and Culture Factors Minority Millennials Perceive as Important Within their Workplace for Retention

Millennials make up the largest segment of the current workforce. However, research about minority Millennials and their needs are relatively unknown. The purpose of this study was to find out what minority Millennials deemed important within an organization’s culture and the policies and programs that would persuade them to remain with the company. Purposeful sampling was used to identify participants for this study. Participants met the criterion of a Millennial by age, identified as a minority, currently worked at an organization with 50 or more employees in an office location and had worked for their current employer for one year or more. The results of the study indicated that, in terms of company culture, minority Millennials expect diversity, inclusion, and opportunities for minorities in leadership positions. Minority Millennials expect programs that promote continuing education, and opportunities for career growth. Minority Millennials expect competitive benefits packages, pay, and workplace flexibility. Companies can use this information to gain a better understanding of the culture, programs and policies that minority Millennials expect at their workplace. The failure to understand minority Millennials could result in significant turnover and the inability to recruit the diverse workforce that Millennial’s desire

Diel Patterns of Foraging Aggression and Antipredator Behavior in the Trashline Orb-weaving Spider, Cyclosa turbinata

Few studies have rigorously assessed the adaptive value of diel rhythms in animals. We laid the groundwork for assessing the adaptive rhythm hypothesis by assaying diel rhythms of foraging and antipredator behavior in the orb-weaving spider Cyclosa turbinata. When confronted with a predator stimulus in experimental arenas, C. turbinata exhibited thanatosis behavior more frequently and for longer durations during the day. However, assays of antipredator response within webs revealed more complex diel patterns of avoidance behaviors and no pattern of avoidance behavior duration. Assays of prey capture behavior found that the likelihood of exhibiting prey capture behavior varied significantly across times of day and test subjects, but only test subject predicted attack latencies. Although C. turbinata foraging aggression changed over the diel cycle, we found no evidence of a trade-off between foraging behavior and predator vigilance. However, overall patterns of vigilance may be masked by diel changes in antipredator strategies