Two ambiguous figures (Mach's book-figure and the AMBEGUJAS phenomenon) have been studied. They show colour shifts synchronised with the shifts of their alternative phases. The perceived concave phase appeared to have chromatic surface colour, but the perceived convex phase can appear to be in coloured illumination and shadow (film colour). The two perceived reversible shapes of the Mach figure (the book and the tent) and the three perceived alternative shapes of the Mondrians used in the AMBEGUJAS phenomenon (a roof, a ceiling, and a tile) all can appear to have chromatic surface colours in their concave phases but appear to have coloured illumination and shadow in their convex phases
A simulation program for calculating the IV-curve for series connected PV-modules during partial shadowing has been developed and experimentally validated. The software used for modelling the modules is LTspice IV. The validation has been done by means of a comparative analysis using the experimental results obtained in a set of tests performed on the mono-crystalline modules of the Gävle University's laboratory in Sweden. Experimental measurements were carried out in two groups. The first group is a string of six modules with bypass diodes while the second one corresponds to a single PV module. The simulation results of both groups demonstrated a remarkable agreement with the experimental data, which means that the designed model can be used for simulating the influence of shading on the power of a string. The model has been used for analysing the performance of strings of PV modules with shadows and the benefits of installing DC-DC optimizers or module inverters, that minimise the impact of shading, have been investigated.
Background. In a systematic literature review, we investigated the effect on work performance and metabolic and physiological outcomes of interventions aimed at reducing sedentary behaviour (SB) and/or increasing physical activity (PA) during productive work time.
Methods. Scopus was searched for articles published from 1992 until March 12, 2015. We included studies: (1) addressing interventions aimed at reducing SB and/or increasing PA at the workplace, during productive work; (2) using a design including a control group or control condition; (3) being published as a full-length paper in a peer-reviewed journal in English; (4) reporting on work performance outcomes and metabolic and physiological outcomes (i.e. lipid and metabolic profiles, hemodynamic and cardiorespiratory measures and anthropometric measures). Relevant studies were evaluated using the Quality Assess-ment Tool for Quantitative Studies and summarized in a best evidence synthesis.
Results. 18 interventions were included and organized into two categories: (1) alternative workstation interventions (n=15), i.e. sit-stand workstations or “active” workstations; and (2) personalized behavioural interventions (n=3), i.e. interventions involving personalized goals and/or giving behavioural feedback using prompts or messages.There was moderate evidence for alternative workstations not influencing hemodynamics and cardiorespiratory fitness as well as personalized behavioural interventions notinfluencing anthropometric measures. Evidence was insufficient (alternative workstations) or conflicting (personalized behavioral interventions) on lipid and metabolic profiles. For work performance, there was insufficient evidence for personalized behavioural interven-tions and conflicting evidence for alternative workstations. But for the latter, only one out of 11 studies showed a negative effect.
Discussion. Current evidence suggests that work performance is not negatively affected by alternative workstations. Furthermore, there is no strong case for introducing interven-tions aimed at reducing SB and/or increasing PA during productive work time in the hope of getting a positive effect on metabolic and physiological outcomes. However, large-scale, high quality studies with long-term follow-ups are needed before more definite conclusions on this topic can be drawn.
Objective. The present study aimed to elucidate possible physiological mechanisms behind impaired endurance during chewing as previously reported in WAD. We tested the hypothesis of a stronger autonomic reaction in WAD than in healthy subjects in response to dynamic loading of the jaw-neck motor system. Design. Cardiovascular reactivity, muscle fatigue indicies of EMG, and perceptions of fatigue, exhaustion and pain were assessed during standardised chewing. Twenty-one WAD subjects and a gender/age matched control group participated. Baseline recordings were followed by two sessions of alternating unilateral chewing of a bolus of gum with each session followed by a rest period. Results. More than half of the WAD subjects terminated the test prematurely due to exhaustion and pain. In line with our hypothesis the chewing evoked an increased autonomic response in WAD exhibited as a higher increase in heart rate as compared to controls. Furthermore, we saw consistently higher values of arterial blood pressure for WAD than for controls across all stages of the experiment. Masseter EMG did not indicate muscle fatigue nor were there group differences in amplitude and mean power frequency. Pain in the WAD group increased during the first session and remained increased, whereas no pain was reported for the controls. Conclusion. More intense response to chewing in WAD might indicate pronounced vulnerability to dynamic loading of the jaw-neck motor system with increased autonomic reactivity to the test. Premature termination and autonomic involvement without EMG signs of muscle fatigue may indicate central mechanisms behind insufficient endurance during chewing.
There are comparable as well as non comparable factors for personnel involved in ambulance and emergency services. The aim of this study was to describe and compare the ambulance and emergency personnel-rated health, physical activity, diet and work-related stress factors and some physiological measurements. The groups were recruited through convenience sampling. Questionnaire was used as data collection method. In addition, physiological measurements of all participants were measured at one occasion. Important relationships emerged regarding health status, perceived fatigue and workload of ambulance personnel. Emergency services of physical activity showed a major difference in relation to ambulance personnel. Job satisfaction was perceived as good in both occupational groups, however, experienced ambulance personnel more psychologically stress. Significant difference was seen between the groups regarding fatigue after a session. Obese and those with high waistlines was over-represented in the ambulance. There were more ambulance personnel staffs that were treated for hypertension and /or diabetes. Differences were found between the groups regarding hypertension, diabetes and physical activity. It was concluded, the lifestyle factors that can prevent the risk of cardiovascular disease and metabolic syndrome, are the ones, were not overweight, exercise regularly, had a good diet and experienced a good job satisfaction.