489 research outputs found

    Distribution and Density of Zebra Mussels (Dreissena Polymorpha Pallas, 1771) and Related Some Environmental Properties in Euphrates River, Iraq

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    The present study was carried on the Euphrates river /middle of Iraq, from October 2011 to September 2012 between Al-Musayyib city and Twereej City. Sampling were monthly from three sites in study area for studying some physical and chemical properties to river water ( air &water temperature , p H , EC , TDS ,TSS , Dissolved oxygen , transparency ,Total alkalinity , Total hardness, calcium , magnesium )  , also measured the concentration of chlorophell -a as indicator of biomass and primary productivity in Euphrates river. This study include collected the samples of zebra mussel from study sites to calculated the density and distribution of the species.The results showed the impact of spatial and temporal variation of environmental properties under study on the distribution and density of D.polymorpha .The species was recorded during most of time and sites of study and this species being invasive species  was recorded for the first time in this region. Fluctuation was observed in the total density of D.polymorpha and the highest values were recorded in the sites (3) ( 23.7 individual /m2) during March 2012 and absente during October 2011 and September 2012 . Statistical analysis was done using the canonical correspondence analysis (CCA). Keywords: Zebra mussel; Biodiversity; Invasive species; Euphrates River; Iraq

    Performance of Anti-Lock Braking Systems Based on Adaptive and Intelligent Control Methodologies

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    Automobiles of today must constantly change their speeds in reaction to changing road and traffic circumstances as the pace and density of road traffic increases. In sophisticated automobiles, the Anti-lock Braking System (ABS) is a vehicle safety system that enhances the vehicle's stability and steering capabilities by varying the torque to maintain the slip ratio at a safe level. This paper analyzes the performance of classical control, model reference adaptive control (MRAC), and intelligent control for controlling the (ABS). The ABS controller's goal is to keep the wheel slip ratio, which includes nonlinearities, parametric uncertainties, and disturbances as close to an optimal slip value as possible. This will decrease the stopping distance and guarantee safe vehicle operation during braking. A Bang-bang controller, PID, PID based Model Reference Adaptive Control (PID-MRAD), Fuzzy Logic Control (FLC), and Adaptive Neuro-Fuzzy Inference System (ANFIS) controller are used to control the vehicle model. The car was tested on a dry asphalt and ice road with only straight-line braking. Based on slip ratio, vehicle speed, angular velocity, and stopping time, comparisons are performed between all control strategies. To analyze braking characteristics, the simulation changes the road surface condition, vehicle weight, and control methods. The simulation results revealed that our objectives were met. The simulation results clearly show that the ANFIS provides more flexibility and improves system-tracking precision in control action compared to the Bang-bang, PID, PID-MRAC, and FLC

    Feeling Safe in the Dark : Examining the Effect of Entrapment, Lighting Levels, and Gender on Feelings of Safety and Lighting Policy Acceptability

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    This research examined to what extent physical factors, notably lighting and entrapment (blocked escape), and individual factors, notably gender, affect feelings of safety and the acceptability of reduced lighting levels. The authors reasoned that acceptability of reduced street lighting depends on perceived safety, which in turn depends on entrapment, lighting, and gender. Virtual representations of a residential street were used, systematically manipulating entrapment and lighting levels. As expected, people felt less safe in lower lighting and higher entrapment settings, and these settings were evaluated as less acceptable. Although women perceived a situation as less safe compared with men, the authors found no gender differences in acceptability, which extends previous research. Importantly, as hypothesized, perceived safety mediated the effect of lighting on acceptability levels, suggesting that people can accept lower lighting levels when social safety is not threatened

    Using manipulated photographs to identify features of streetscapes that may encourage older adults to walk for transport

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    Experimental evidence of environmental features important for physical activity is challenging to procure in real world settings. The current study aimed to investigate the causal effects of environmental modifications on a photographed street\u27s appeal for older adults\u27 walking for transport. Secondly, we examined whether these effects differed according to gender, functional limitations, and current level of walking for transport. Thirdly, we examined whether different environmental modifications interacted with each other. Qualitative responses were also reported to gain deeper insight into the observed quantitative relationships. Two sets of 16 panoramic photographs of a streetscape were created, in which six environmental factors were manipulated (sidewalk evenness, traffic level, general upkeep, vegetation, separation from traffic, and benches). Sixty older adults sorted these photographs on appeal for walking for transport on a 7-point scale and reported qualitative information on the reasons for their rankings. Sidewalk evenness appeared to have the strongest influence on a street\u27s appeal for transport-related walking. The effect of sidewalk evenness was even stronger when the street\u27s overall upkeep was good and when traffic was absent. Absence of traffic, presence of vegetation, and separation from traffic also increased a street\u27s appeal for walking for transport. There were no moderating effects by gender or functional limitations. The presence of benches increased the streetscape\u27s appeal among participants who already walked for transport at least an hour/week. The protocols and methods used in the current study carry the potential to further our understanding of environment-PA relationships. Our findings indicated sidewalk evenness as the most important environmental factor influencing a street\u27s appeal for walking for transport among older adults. However, future research in larger samples and in real-life settings is needed to confirm current findings

    Faba bean (Vicia faba L.) seeds darken rapidly and phenolic content falls when stored at higher temperature, moisture and light intensity

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    Faba beans cv. Fiesta with seed moisture content (SMC) modified to 8, 10, 12 and 14% were packed in polyethylene lined aluminium foil bags and stored at 5, 15, 20, 25, 30, 37, 45, 50 or 60 C ( 2 C) for one year. Samples were analysed for moisture content and seed coat (testa) colour over the storage period using a chroma meter. A continuous increase in L* and b* values was found in all samples with the passage of time whereas a *values first increased and then decreased in samples stored at relatively high temperatures (= 37 C). The initial beige testa colour changed to light brown, dark reddish brown or almost black depending on storage conditions. The higher the temperature and SMC the faster the rate of change in colour (E ab* values). Seeds with 8% SMC had more stable testa colour compared to seeds with higher SMC. Exposure to artificial light (350 mol m -2 s -1) substantially accelerated the colour darkening. Cotyledon stored at 37+2 C also darkened with the storage time. A loss in total free phenolics, total tannins and proanthocyanidins was found with increased darkness of testa and cotyledons during storage

    Assessing cycling-friendly environments for children: are micro-environmental factors equally important across different street settings?

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    BACKGROUND: As physical activity levels decrease as children age, sustainable and accessible forms of physical activity are needed from a young age. Transportation cycling is one such physical activity and has been associated with many benefits. The aims of the study were to identify whether manipulating micro-environmental factors (e.g. speed limis, evenness of cycle path) within a photographed street influences the perceived supportiveness for transportation cycling; and whether changing these micro-environmental factors has the same effect across different street settings. METHODS: We recruited 305 fifth and sixth grade children and their parents from twelve randomly selected primary schools in Flanders, Belgium. They completed a web-based questionnaire including 12 choice-based conjoint tasks, in which they had to choose between two possible routes depicted on manipulated photographs, which the child would cycle along. The routes differed in four attributes: general street setting (enclosed, half open, open), evenness of cycle path (very uneven, moderately uneven, even), speed limit (70 km/h, 50 km/h, 30 km/h) and degree of separation between a cycle path and motorised traffic (no separation, curb, hedge). Hierarchical Bayes analyses revealed the relative importance of each micro-environmental attribute across the three street settings. RESULTS: For each attribute, children and their parents chose routes that had the best alternative (i.e. open street setting, even cycle path, 30 km/h, a hedge separating the cycle path from motorised traffic). The evenness of the cycle path and lower speed limit had the largest effect for the children, while the degree of separation and lower speed limit had the largest effect for their parents. Interactions between micro-scale and macro-scale factors revealed differences in the magnitude but not direction of their effects on route choice. The results held across the different kinds of street settings tested. CONCLUSIONS: Improving micro-scale attributes may increase the supportiveness of a street for children\u27s transportation cycling. We call for on-site research to test effects of changes in micro-environmental attributes on transportation cycling among children

    Mind your step: the effects of mobile phone use on gaze behavior in stair climbing

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    Stair walking is a hazardous activity and a common cause of fatal and non-fatal falls. Previous studies have assessed the role of eye movements in stair walking by asking people to repeatedly go up and down stairs in quiet and controlled conditions, while the role of peripheral vision was examined by giving participants specific fixation instructions or working memory tasks. We here extend this research to stair walking in a natural environment with other people present on the stairs and a now common secondary task: Using one's mobile phone. Results show that using the mobile phone strongly draws one's attention away from the stairs, but that the distribution of gaze locations away from the phone is little influenced by using one's phone. Phone use also increased the time needed to walk the stairs, but handrail use remained low. These results indicate that limited foveal vision suffices for adequate stair walking in normal environments, but that mobile phone use has a strong influence on attention, which may pose problems when unexpected obstacles are encountered

    Bringing the margins into the middle:Reflections on racism, class and the racialized outsider

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    This paper explores Virdee’s account of how racialized minorities in socialist movements ‘played an instrumental role in trying to align struggles against racism with those against class exploitation’ (p. 164). In so doing, Virdee makes an important intervention at a time when popular historians and other ideologues are colluding in the elevation of myths and – no doubt in their view – noble lies that preclude these stories. Moving through theoretical debates concerning the relationships between race and class, the nature and form of sociologies of ‘outsiders’, to political issues of mobilization, Virdee’s book successfully brings in from the margins an account the multi-ethnic character of the working class in England from the very moment of its inception

    Pedestrian Injury and Human Behaviour: Observing Road-Rule Violations at High-Incident Intersections

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    Background Human behaviour is an obvious, yet under-studied factor in pedestrian injury. Behavioural interventions that address rule violations by pedestrians and motorists could potentially reduce the frequency of pedestrian injury. In this study, a method was developed to examine road-rule non-compliance by pedestrians and motorists. The purpose of the study was to examine the potential association between violations made by pedestrians and motorists at signalized intersections, and collisions between pedestrians and motor-vehicles. The underlying hypothesis is that high-incident pedestrian intersections are likely to vary with respect to their aetiology, and thus are likely to require individualized interventions – based on the type and rate of pedestrian and motorist violation. Methods High-incident pedestrian injury intersections in Vancouver, Canada were identified using geographic information systems. Road-rule violations by pedestrians and motorists were documented at each incident hotspot by a team of observers at several different time periods during the day. Results Approximately 9,000 pedestrians and 18,000 vehicles were observed in total. In total for all observed intersections, over 2000 (21%) pedestrians committed one of the observed pedestrian road-crossing violations, while approximately 1000 (5.9%) drivers committed one of the observed motorist violations. Great variability in road-rule violations was observed between intersections, and also within intersections at different observation periods. Conclusions Both motorists and pedestrians were frequently observed committing road-rule violations at signalized intersections, suggesting a potential human behavioural contribution to pedestrian injury at the study sites. These results suggest that each intersection may have unique mechanisms that contribute to pedestrian injury, and may require targeted behavioural interventions. The method described in this study provides the basis for understanding the relationship between violations and pedestrian injury risk at urban intersections. Findings could be applied to targeted prevention campaigns designed to reduce the number of pedestrian injuries at signalized intersections
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