Human Physiological Capabilities for Prolonged Manual Lifting Tasks

The objective of this study was to determine human physiological capabilities for prolonged lifting tasks performed from the floor to table height. Frequency and weight of load were the independent variables. Oxygen consumption, minute ventilation, and heart rate were the dependent variables. Physiological responses were monitored continuously for each frequency-load combination. Eleven male subjects participated in the experiments. The duration of each experimental session was controlled by the subject. Each subject was instructed to perform the lifting task continuously until he could not maintain it any longer due to complete physical exhaustion. Each subject was given 10 minutes of rest every 50 minutes of work and 1 hour for lunch after the fourth hour of work. The upper limit of lifting duration was set to 8 hours. One of the main findings obtained from this study was that a physiological fatigue limit (PFL) is a function of lifting task parameters (frequency, weight of load, and task duration). Thus, one cannot recommend a single PFL value such as 1 liter/min for lifting tasks of varied work durations.     

The nuclear freeze resolution: A question of empowerment.

The American Psychological Association has done little to empower the nuclear freeze resolution (NFR) adopted in 1982. The general debate on the issues of advocacy, competency, and ethics should be suspended so that the issues associated specifically with the NFR can be resolved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Guidelines for the safe use of wastewater in agriculture: revisiting WHO guidelines.

The use of wastewater in agriculture is occurring more frequently because of water scarcity and population growth. Often the poorest households rely on this resource for their livelihood and food security needs. However, there are negative health implications of this practice that need to be addressed. WHO developed Guidelines for the Safe Use of Wastewater in Agriculture in 1989. The Guidelines are currently being revised based on new data from epidemiological studies, quantitative microbial risk assessments and other relevant information. WHO guidelines must be practical and offer feasible risk management solutions that will minimize health threats and allow for the beneficial use of scarce resources. To achieve the greatest impact on health, guidelines should be implemented with other health measures such as: health education, hygiene promotion, provision of adequate drinking water and sanitation, and other health care measures.     

Identifying correlates of breaks in occupational sitting: a cross-sectional study

Office workers are commonly targeted in interventions to modify their sitting behaviour, yet there is limited evidence of the correlates of breaks in sitting to inform intervention development. This study identifies the individual, workplace and spatial configuration correlates of the frequency of breaks in sitting (number/hour) in office workers (n?=?5531) stratified by office type (private-enclosed, shared, open plan). All behaviours and potential correlates were measured via self-report using an online cross-sectional survey. Regression analyses revealed age was the only socio-demographic characteristic associated with frequency of breaks in sitting in all office types. Greater job autonomy and local connectivity were positively associated with frequency of breaks in sitting in shared and open-plan offices. In open-plan offices co-worker proximity was negatively associated with frequency of breaks in sitting. Co-worker visibility was positively associated with frequency of breaks in sitting in all office types. This study demonstrates that individual, workplace and spatial configuration factors are all associated with the frequency of breaks in sitting and that these relationships differ by office type. These observations extend prior studies that have only examined correlates at a single level (e.g. the individual). This evidence could be useful to guide future interventions in the design of workplaces to increase breaks in sitting and workers’ physical activity.     

Mutual Information for Stochastic Signals and LÉvy Processes

In this paper, some relations between estimation and mutual information are given by expressing two mutual information calculations in terms of two distinct estimation errors. Specifically the mutual information between a stochastic signal and a pure jump Levy process whose rate function depends on the signal is expressed in terms of a filtering error and the rate of change of this mutual information with respect to a parameter multiplying the rate function of the Levy process is expressed in terms of a smoothing error. These results generalize the analogous mutual information results for some Gaussian noise processes with additive stochastic signals.     

Antiepileptic drug therapy and sexual function in men with epilepsy

PURPOSE: To study the effects of antiepileptic drugs (AEDs) on sex hormone levels and sexual activity in a group of men attending a hospital-based epilepsy clinic. METHODS: One hundred eighteen men being treated with AED therapy, 32 with epilepsy but not receiving AEDs, and 34 controls were recruited. All subjects were aged 18-65 years. Blood (20 ml) was removed for hormone assays, after which each subject completed a validated questionnaire [Sexuality Experience Scores (Frenken and Vennix, 1981)] aimed at exploring the individuals' sexual activity and attitudes to sexual morality. RESULTS: Men taking carbamazepine (CBZ) only had significantly higher mean sex hormone-binding globulin (SHBG) levels than the control group. The CBZ group also had a significantly lower mean DHEAS concentration than the control, untreated, and sodium valproate (VPA) monotherapy groups. The phenytoin monotherapy group (PHT) had a significantly higher mean SHBG than both the control and untreated groups, and had a significantly higher mean total testosterone (TT) value than the control untreated, CBZ, and VPA groups, and a significantly lower mean DHEAS than the controls, untreated, and VPA groups. Men receiving more than one AED had significantly higher mean SHBG concentrations compared with control, untreated, and VPA groups. In addition, the polytherapy group's mean TT was significantly higher than the control and VPA groups, although its mean DHEAS concentration was lower than the control, untreated, and VPA groups. There were no significant differences between the study groups in mean FT, Budrostenedione (AND), or estradiol levels. But the CBZ, PHT, and polytherapy groups had significantly lower mean free and rogen index (FAI) than the controls. The CBZ group had a lower mean FAI than the VPA group. The polytherapy group had a lower FAI than the untreated group. Sexuality Experience Scores (SES) showed that those men receiving AEDs embraced a stricter sexual morality than the controls and untreated, and expressed greater satisfaction with their marriages than the control and untreated groups. CONCLUSIONS: Seizure type did not affect SES scores. Multiple regression showed men who had received further education were less accepting of strict sexual morality.     

A note on sampling and parameter estimation in linear stochasticsystems

Numerical differentiation formulas that yield consistent least squares parameter estimates from sampled observations of linear, time invariant higher order systems have been introduced previously by Duncan et al. (1994). The formulas given by Duncan et al. have the same limiting system of equations as in the continuous time case. The formula presented in this note can be characterized as preserving asymptotically a partial integration rule. It leads to limiting equations for the parameter estimates that are different from the continuous case, but they again imply consistency. The numerical differentiation formulas given here can be used for an arbitrary linear system, which is not the case in the previous paper by Duncan et al     

Study of the Free Surface Flow on an Ogee-Crested Fish Bypass

A study of the free surface flow on an ogee-crested fish bypass is presented. The commercial computational fluid dynamics (CFD) code Fluent 6.1 was used to perform the simulations. Structured/unstructured hybrid grids were used to accommodate the complex geometry that included gate slots, flow control gates, and an aeration slot. The volume of fluid (VOF) approach was used to model the water/air interface. The fish bypass exhibits complex free surface features including free nappes and air entrainment from the air slots. Free surface elevations on both sides of the nappe, pressure along the ogee surface, and discharge rating curves were compared against 1:24 experimental data from the laboratory model for different headwater elevations and gate settings. Limited comparison against measured velocities was also performed. Once deemed reliable through validation against experimental data, the computational model was used to analyze the flow field, supplementing the areas of limited experimental data. Though the paper presents the final fish bypass design, CFD was used to guide the design process and provide insight for several variations in the geometry.