Load distribution during sit-stand-sit using an instrumented chair

Paper examining the forces through the body during standing up and sitting down by means of force plates and transducers

Numerical simulation of rivulet evolution on a horizontal cable subject to an external aerodynamic field

On wet and windy days, the inclined cables of cable-stayed bridges may experience a large amplitude oscillation known as rain-wind-induced vibration (RWIV). It has previously been shown by in situ and wind-tunnel studies that the formation of rain-water accumulations or ‘rivulets’ at approximately the separation points of the external aerodynamic flow field and the resulting effect that these rivulets have on this field may be one of the primary mechanisms for RWIV. A numerical method has been developed to undertake simulations of certain aspects of RWIV, in particular, rivulet formation and evolution. Specifically a two-dimensional model for the evolution of a thin film of water on the outer surface of a horizontal circular cylinder subject to the pressure and shear forces that result from the external flow field is presented. Numerical simulations of the resulting evolution equation using a bespoke pseudo-spectral solver capture the formation of two-dimensional rivulets, the geometry, location and growth rate of which are all in good agreement with previous studies. Examinations of how the distribution and magnitude of aerodynamic loading and the Reynolds number influence the rivulet temporal evolution are undertaken, the results of which indicate that while all three affect the temporal evolution, the distribution of the loading has the greatest effect

New developments in rain–wind-induced vibrations of cables

On wet and windy days, the inclined cables of cable stayed bridges can experience large amplitude, potentially damaging oscillations known as rain-wind-induced vibration (RWIV). RWIV is believed to be the result of a complicated non-linear interaction between rivulets of rain water that run down the cables and the wind loading on the cables from the unsteady aerodynamics; however, despite a considerable international research effort, the underlying physical mechanism that governs this oscillation is still not satisfactorily understood. An international workshop on RWIV was held in April 2008, hosted at the University of Strathclyde. The main outcomes of this workshop are summarised in the paper. A numerical method to investigate aspects of the RWIV phenomenon has recently been developed by the authors, which couples an unsteady aerodynamic solver to a thin-film model based on lubrication theory for the flow of the rain water to ascertain the motion of the rivulets owing to the unsteady aerodynamic field. This novel numerical technique, which is still in the relatively early stages of development, has already provided useful information on the coupling between the external aerodynamic flow and the rivulet, and a summary of some of the key results to date is presented

Numerical Renormalization Group Study of the O(3)-symmetric Anderson Model

We use the numerical renormalization group method to study the O(3)-symmetric version of the impurity Anderson model of Coleman and Schofield. This model is of general interest because it displays both Fermi liquid and non-Fermi liquid behaviour, and in the large $U$ limit can be related to the compactified two channel Kondo model of Coleman, Ioffe and Tsvelik. We calculate the thermodynamics for a parameter range which covers the full range of behaviour of the model. We find a non-Fermi liquid fixed point in the isotropic case which is unstable with respect to channel anisotropy.Comment: 10 pages, LaTeX, 8 figures includes as eps-file

Estimation of badger abundance using faecal DNA typing

1.Wildlife management and conservation programmes often require accurate information on population density, but this can be difficult to obtain, particularly when the species in question is nocturnal or cryptic. Badger populations in Britain are of intense management interest because they are a wildlife reservoir host of bovine tuberculosis (TB). Attempts to manage this infection in badgers, whether by population control or vaccination, require reliable methods of estimating population size. In addition, such estimates are also required to support research into badger ecology and TB epidemiology. Currently, the most accurate estimates of local badger population size are obtained from labour-intensive and time-consuming mark–recapture studies. 2. In recent years, DNA has been successfully extracted from the faeces of certain mammals, and used to generate a genetic profile of the defecating individual. Here we report on an application of this technology to estimate badger abundance.3.Faecal samples were collected on 10 consecutive days from every freshly deposited dropping at latrine sites close to occupied setts in three badger social groups. Badger DNA was extracted from 89% of samples, and 20 different individuals were reliably identified. The genotypes derived from the faecal samples were compared with those obtained from blood or samples from badgers live trapped at the same setts.4.The faecal genotypes from badgers with known trap histories revealed that latrines were used equally by males and females, and by badgers ranging in age from cubs(< 1 year old) to 9 years old. Individual badgers used the latrines on between one and six different nights. Rarefaction analysis produced abundance estimates that closely matched those obtained from live trapping. 5.Synthesis and applications. Systematic sampling and genetic typing of fresh faeces from badger latrines can provide data that can be used to estimate abundance accurately.This approach requires considerably less human resources than repeated live trapping and mark–recapture. The technique may be valuable for future badger research and management in relation to bovine TB, where accurate estimates of abundance at a local scale are required

The impact of CoRoT on close binary research

The space experiment CoRoT will provide continuous monitoring and high accuracy light curves of about sixty thousand stars. Selected binary systems will be observed in the Additional Program frame as targets of long and continuous pointed observations. Moreover, thousands of new binaries will certainly be detected and hundreds of them will have extremely accurate light curves. This will allow studies of fine effects on the light curves, monitoring of stellar activity and, in combination with ground-based observations, will provide exquisite determination of stellar parameters. Among the new discoveries of interesting systems of special value will be those of low mass binaries.Comment: 6 pages, 2 figures, contribution to "Colse binaries in the 21th century", Syros (Greece), June 2005. To be published by Ap&S

Family support for the elderly in Zimbabwe

This article reports on a study of family support for the elderly in Zimbabwe, conducted among a sample of 150 persons aged 55 years and older. The sample was drawn in an urban area (Harare) and a commercial farming area (Bromley-Ruwa), and among residents of the communal lands of Chikwaka and Goromonzi. The majority of the respondents were married; some of the men were polygamous. Six per cent of the respondents were childless. Where the respondents had children, a large number of the children were economically inactive. Many of the children were unable to support their parents because of their own family obligations. The majority of the children neither lived with their parents nor visited them regularly. The elderly parents received few remittances from their children, even those who were employed. Some respondents were supporting their children. Policy options for encouraging family support of the elderly are suggested

Direct measurement of swimming and diving kinematics of giant Atlantic bluefin tuna (Thunnus thynnus)

Tunas possess a range of physiological and mechanical adaptations geared towards high-performance swimming that are of considerable interest to physiologists, ecologists and engineers. Advances in biologging have provided significant improvements in understanding tuna migrations and vertical movement patterns, yet our understanding of the locomotion and swimming mechanics of these fish under natural conditions is limited. We equipped Atlantic bluefin tuna (Thunnus thynnus) with motion-sensitive tags and video cameras to quantify the gaits and kinematics used by wild fish. Our data reveal significant variety in the locomotory kinematics of Atlantic bluefin tuna, ranging from continuous locomotion to two types of intermittent locomotion. The tuna sustained swimming speeds in excess of 1.5 m s−1 (0.6 body lengths s−1), while beating their tail at a frequency of approximately 1 Hz. While diving, some descents were entirely composed of passive glides, with slower descent rates featuring more gliding, while ascents were primarily composed of active swimming. The observed swimming behaviour of Atlantic bluefin tuna is consistent with theoretical models predicting such intermittent locomotion to result in mechanical and physiological advantages. Our results confirm that Atlantic bluefin tuna possess behavioural specializations to increase their locomotory performance, which together with their unique physiology improve their capacity to use pelagic and mesopelagic habitats

Interaction between nitric oxide signaling and gap junctions: Effects on vascular function

Nitric oxide signaling, through eNOS (or possibly nNOS), and gap junction communication are essential for normal vascular function. While each component controls specific aspects of vascular function, there is substantial evidence for cross-talk between nitric oxide signaling and the gap junction proteins (connexins), and more recently, protein protein association between eNOS and connexins. This review will examine the evidence for interaction between these pathways in normal and diseased arteries, highlight the questions that remain about the mechanisms of their interaction, and explore the possible interaction between nitric oxide signaling and the newly discovered pannexin channels. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics. (C) 2011 Elsevier B.V. All rights reserved

Fatores prognósticos em câncer de cólon localmente avançado tratado com ressecção extendida

The impact of clinical, pathologic, and surgical variables on the postoperative morbidity, mortality, and survival of patients undergoing extended resections of colon carcinoma were evaluated. METHODS: The medical records of 95 patients who underwent extended resections for colon carcinoma between 1953 and 1996 were reviewed. In all cases, in addition to colectomy, 1 or more organs and/or structures were resected en bloc due to a macroscopically based suspicion of tumor invasion. The clinical, pathologic, and surgical parameters were analyzed. Overall survival rates were analyzed according to the method of Kaplan and Meier. Multivariate analysis was performed using the Cox proportional hazards model. RESULTS: Eighty-six patients were treated by curative surgeries and the remaining by palliative resections. Invasion of the organs and/or adjacent structures and regional lymph nodes was found microscopically in 48 and 31 patients, respectively. The median follow-up without postoperative mortality was 47.7 months. The 5-year overall survival rates was 52.6%. The 5-year overall survival rates for patients undergoing curative and palliative surgeries was 58.3% and 0%, respectively. The mean survival time in the palliative surgery group was 3.1 months. Multivariate analysis showed that Karnofsky performance status was strongly related to the risk of postoperative complications (P = .01), and postoperative deaths were associated with the type of surgery and Karnofsky performance status at the time of admission (P = .001). CONCLUSIONS: Some patients with locally advanced colon adenocarcinomas undergoing extended resections have a 5-year overall survival rates of 58.3%. Patients could benefit from palliative-intent procedures, but these measures should cautiously be indicated and avoided in patients with low Karnofsky performance status due to high rates of postoperative mortality and poor survival.Foi avaliado o impacto de variáveis clínicas, patológicas e cirúrgicas na morbidade e mortalidade pós operatórias de pacientes submetidos à ressecção extendida de carcinoma do cólon. MÉTODOS: Prontuários médicos de 95 pacientes submetidos á ressecção extendida de carcinoma de cólon entre os anos de 1953 e 1996 foram revisados. Em todos os casos, além de colectomia, um ou mais órgãos e/ou estruturas foram ressecados em bloco devido á suspeição de invasão tumoral macroscópica. As variáveis clínicas, patológicas e cirúrgicas foram analizadas. As taxas de sobrevida global foram analizadas de acordo com o método de Kaplan and Meier. A análise multivariada foi realizada empregando-se o modelo de risco proporcional de Cox. RESULTADOS: Oitenta e seis pacientes foram tratados com cirurgia curativa e o restante com ressecção paliativa. Invasão microscópica de órgãos e/ou estruturas adjacentes e linfonodos regionais foi encontrada em 48 e 31 pacientes respectivamente. O tempo de seguimento mediano, sem mortalidade pós operatória, foi de 47.7 meses. A taxa de sobrevida global em 5 anos foi de 52.6%. A taxa de sobrevida global para pacientes submetidos à cirurgia curativa e paliativa foi de 58.3% e zero, respectivamente. A sobrevida mediana no grupo de pacientes com cirurgia paliativa foi de 3.1 meses. A análise multivariada mostrou que a performance status de Karnofsky fortemente correlacionou com risco de complicações pós operatórias (p=0.01), e que o risco de morte pós operatória estava associada com o tipo de cirurgia e a performance status de Karnofsky na admissão (p=0.001) CONCLUSÕES: Pacientes com adenocarcinoma de cólon localmente avançados submetidos à ressecção extendida têm taxa de sobrevida global em 5 anos de 58.3% Este tipo de cirurgia pode ser empregada com intuito paliativo, mas deve ter indicação criteriosa e ser evitada em pacientes com baixa performance status de Karnofsky devido às altas taxas de mortalidade pós operatória e baixa sobrevida