Understanding the effect of seams on the aerodynamics of an association football

The aerodynamic properties of an association football were measured using a wind tunnel arrangement. A third scale model of a generic football (with seams) was used in addition to a 'mini-football'. As the wind speed was increased, the drag coefficient decreased from 0.5 to 0.2, suggesting a transition from laminar to turbulent behaviour in the boundary layer. For spinning footballs, the Magnus effect was observed and it was found that reverse Magnus effects were possible at low Reynolds numbers. Measurements on spinning smooth spheres found that laminar behaviour led to a high drag coefficient for a large range of Reynolds numbers, and Magnus effects were inconsistent, but generally showed reverse Magnus behaviour at high Reynolds number and spin parameter. Trajectory simulations of free kicks demonstrated that a football that is struck in the centre will follow a near straight trajectory, dipping slightly before reaching the goal, whereas a football that is struck off centre will bend before reaching the goal, but will have a significantly longer flight time. The curving kick simulation was repeated for a smooth ball, which resulted in a longer flight time, due to increased drag, and the ball curving in the opposite direction, due to reverse Magnus effects. The presence of seams was found to encourage turbulent behaviour, resulting in reduced drag and more predictable Magnus behaviour for a conventional football, compared with a smooth ball. © IMechE 2005

Measurement of Finger Pad Forces and Friction using Finger Nail Mounted Strain Gauges

There are currently few techniques for measuring in-vivo the forces exerted by the finger pads when handling objects and friction levels in the interface. Those that exist are intrusive and affect the manner in which an object is gripped or the interface between finger and object. A non-intrusive method would enable data to be gathered on object grip and manipulation that could improve designs to aid usability and inclusivity. The aim of this work was to assess the feasibility of determining finger pad forces and friction between a finger pad and a surface using strain gauges mounted to finger nails. The index finger and thumb were assessed as these have been shown to be used most for gripping in everyday tasks. Initially Digital Image Correlation was used to study strain across whole finger nails during a loading event to establish where it would be best to mount the strain gauges. After attachment of the strain gauges, tests were carried out normally loading finger pads against a force plate to determine strain/force relationships and the effects of slight finger side roll. Sliding tests were then also carried out in dry and lubricated conditions to see how strain varied when normal force was kept constant. Clear relationships have been established between strain and force that could be used to calibrate from measurements taken during actual object manipulation. Changing friction has also been shown to affect strain

Formación inicial del profesorado de ciencias en Francia, Inglaterra y Gales y España : análisis de la organización de los estudios y nuevas tendencias

This paper contains a comparative analysis of university courses on initial secondary teacher training in theses countries. The aim is to sort out the common components in these training systems. We also point out some contemporary trends in this field, trying to increase the degree of professionalisation of these courses

Morphological parametric mapping of 21 skin sites throughout the body using optical coherence tomography

Background Changes in body posture cause changes in morphological properties at different skin sites. Although previous studies have reported the thickness of the skin, the details of the postures are not generally given. This paper presents the effect of a change in posture on parameters such as thickness and surface roughness in 21 load-bearing and non-load-bearing sites. Materials and methods A total of 12 volunteers (8 males and 4 females) were selected in an age group of 18–35 years and of Fitzpatrick skin type I-III. Images were captured using a clinically-approved VivoSight® optical coherence tomography system and analysed using an algorithm provided by Michelson Diagnostics. Results Overextension (extending joints to full capacity) resulted in changes to thickness, roughness and undulation of the skin around the body. Discussion and conclusion The load-bearing regions have thicker skin compared to non-load-bearing sites. This is the first time that undulation topography of the stratum corneum–stratum lucidum and the dermal–epidermal junction layers have been measured and reported using statistical values such as Ra. The data presented could help to define new skin layer models and to determine the variability of the skin around the body and between participants

Complete solution of a constrained tropical optimization problem with application to location analysis

We present a multidimensional optimization problem that is formulated and solved in the tropical mathematics setting. The problem consists of minimizing a nonlinear objective function defined on vectors over an idempotent semifield by means of a conjugate transposition operator, subject to constraints in the form of linear vector inequalities. A complete direct solution to the problem under fairly general assumptions is given in a compact vector form suitable for both further analysis and practical implementation. We apply the result to solve a multidimensional minimax single facility location problem with Chebyshev distance and with inequality constraints imposed on the feasible location area.Comment: 20 pages, 3 figure

Skeletal muscle dysfunction is associated with derangements in mitochondrial bioenergetics (but not UCP3) in a rodent model of sepsis

Muscle dysfunction is a common feature of severe sepsis and multi-organ failure. Recent evidence implicates bioenergetic dysfunction and oxidative damage as important underlying pathophysiological mechanisms. Increased abundance of uncoupling protein-3 (UCP-3) in sepsis suggests increased mitochondrial proton leak, which may reduce mitochondrial coupling efficiency but limit ROS production. Using a murine model, we examined metabolic, cardiovascular and skeletal muscle contractile changes following induction of peritoneal sepsis in wild-type and Ucp3(-/-) mice. Mitochondrial membrane potential (Δψm) was measured using two-photon microscopy in living diaphragm, and contractile function was measured in diaphragm muscle strips. The kinetic relationship between membrane potential and oxygen consumption was determined using a modular kinetic approach in isolated mitochondria. Sepsis was associated with significant whole body metabolic suppression, hypothermia and cardiovascular dysfunction. Maximal force generation was reduced and fatigue accelerated in ex vivo diaphragm muscle strips from septic mice. Mitochondrial membrane potential was lower in the isolated diaphragm from septic mice despite normal substrate oxidation kinetics and proton leak in skeletal muscle mitochondria. Even though wild-type mice exhibited an absolute 26 ± 6% higher UCP-3 protein abundance at 24 hours, no differences were seen in whole animal or diaphragm physiology, nor in survival rates, between wild-type and Ucp3(-/-) mice. In conclusion, this murine sepsis model shows a hypometabolic phenotype with evidence of significant cardiovascular and muscle dysfunction. This was associated with lower Δψm and alterations in mitochondrial ATP turnover and phosphorylation pathway. However, UCP-3 does not play an important functional role, despite its upregulation

Eu ganho, a empresa ganha ou ganhamos juntos? Traços moderados do Dark Triad e a maximização de lucros

This article analyzes the relationship between the maximization of personal and company gains and the moderate traits of the Dark Triad. The relevance of choosing this topic lies in investigating the attitude of executives who exhibit characteristics of a moderate intensity between the strong and weak traits. It is proven that the vision and charisma of narcissistic individuals, the strategy and tactics of Machiavellian individuals, and the creativity and good strategic thinking of psychopathic individuals are differentiating characteristics that enhance successful and integrative leadership and that are far from the more accentuated and opportunistic attitudes related to the strong traits, whose practices involve dishonest actions for personal gain. This evidence creates the possibility for strengthening the research in the accounting area, especially on the behavioral approach, in order to promote its interface with psychology and clarify how personality, values, and experiences influence managers’ choices when conducting business and how workers and companies are impacted by these decisions. The study is empirical-theoretical and involves 263 managers, adopting a survey as its data collection strategy and applying a selfreporting type questionnaire. The data analysis approaches included descriptive statistics, correlations, tests of means, and logistic regressions. In this study, managers with moderate psychopathic traits showed a lower tendency to maximize profit by manipulating results. An opposite tendency was revealed for those with moderate Machiavellian traits. The combined effect of the three Dark Triad traits was significant and positive, revealing opportunistic profit maximization. These findings contribute to future studies that aim to systematically analyze moderate levels of the triad and corroborate the findings that have revealed the common characteristics of manipulation, callousness, and dishonesty when investigating the interactive effect between the traits in question.Este artigo analisa a relação entre a maximização de ganhos pessoais e empresariais e os traços moderados do Dark Triad. A relevância da escolha do tema recai sobre a investigação da atitude de executivos que exibem características com intensidade moderada entre os altos e baixos traços. Comprova-se que a visão e o carisma do indivíduo narcisista, a estratégia e tática do indivíduo maquiavelista e a criatividade e o bom pensamento estratégico do indivíduo psicopata são características diferenciadoras que potencializam uma liderança bem-sucedida e integradora – distante de atitudes negativas mais acentuadas e oportunísticas, concernentes aos altos traços, cujas práticas evidenciam ações desonestas para ganho pessoal. Tais evidências proporcionam a possibilidade de fortalecimento das pesquisas na área contábil, em especial da abordagem comportamental, por promover sua interface com a psicologia para esclarecer como a personalidade, os valores e as experiências influenciam as escolhas dos gestores na condução do negócio e como os funcionários e as empresas são impactados por essas decisões. Trata-se de pesquisa empírico-teórica, realizada com 263 gerentes, adotando o survey como estratégia de coleta de dados – com aplicação de questionário do tipo autorrelato. As abordagens de análise de dados foram: estatística descritiva, correlação, teste de médias e regressão logística. Neste estudo, gestores com traços moderados de Psicopatia evidenciaram menor disposição a maximizar ganhos por meio da manipulação de resultados. Disposição contrária foi revelada para aqueles com traços moderados de Maquiavelismo. O efeito combinado entre os três traços do Dark Triad foi significativo e positivo, com a maximização oportunística de ganhos. Tais achados contribuem com futuras pesquisas que almejem analisar de modo sistemático o nível moderado da tríade e corroboram os achados que revelaram as características comuns de manipulação, insensibilidade e desonestidade quando se investiga o efeito interativo entre os traços em questão

Sub-clinical assessment of atopic dermatitis severity using angiographic optical coherence tomography

Measurement of sub-clinical atopic dermatitis (AD) is important for determining how long therapies should be continued after clinical clearance of visible AD lesions. An important biomarker of sub-clinical AD is epidermal hypertrophy, the structural measures of which often make optical coherence tomography (OCT) challenging due to the lack of a clearly delineated dermal-epidermal junction in AD patients. Alternatively, angiographic OCT measurements of vascular depth and morphology may represent a robust biomarker for quantifying the severity of clinical and sub-clinical AD. To investigate this, angiographic data sets were acquired from 32 patients with a range of AD severities. Deeper vascular layers within skin were found to correlate with increasing clinical severity. Furthermore, for AD patients exhibiting no clinical symptoms, the superficial plexus depth was found to be significantly deeper than healthy patients at both the elbow (p = 0.04) and knee (p < 0.001), suggesting that sub-clinical changes in severity can be detected. Furthermore, the morphology of vessels appeared altered in patients with severe AD, with significantly different vessel diameter, length, density and fractal dimension. These metrics provide valuable insight into the sub-clinical severity of the condition, allowing the effects of treatments to be monitored past the point of clinical remission

Cumulative stress in childhood is associated with blunted reward-related brain activity in adulthood

Early life stress (ELS) is strongly associated with negative outcomes in adulthood, including reduced motivation and increased negative mood. The mechanisms mediating these relations, however, are poorly understood. We examined the relation between exposure to ELS and reward-related brain activity, which is known to predict motivation and mood, at age 26, in a sample followed since kindergarten with annual assessments. Using functional neuroimaging, we assayed individual differences in the activity of the ventral striatum (VS) during the processing of monetary rewards associated with a simple card-guessing task, in a sample of 72 male participants. We examined associations between a cumulative measure of ELS exposure and VS activity in adulthood. We found that greater levels of cumulative stress during childhood and adolescence predicted lower reward-related VS activity in adulthood. Extending this general developmental pattern, we found that exposure to stress early in development (between kindergarten and grade 3) was significantly associated with variability in adult VS activity. Our results provide an important demonstration that cumulative life stress, especially during this childhood period, is associated with blunted reward-related VS activity in adulthood. These differences suggest neurobiological pathways through which a history of ELS may contribute to reduced motivation and increased negative mood