1,419 research outputs found

    The Adaptation of an Ore Feeder to Replace a Chute

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    I believe that by installing apron ore feeders in place of chutes, spillages, manual labor, and loading time could reduced, and greater safety and the average car factor could be increased. Although an apron feeder would be a considerable investment, maintenance should be very low and the feeder would be re-usable many times

    The Invisible Power of MacHines Revisiting the Proposed Flash Order Ban in the Wake of the Flash Crash

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    Technological innovation continues to make trading and markets more efficient, generally benefitting market participants and the investing public. But flash trading, a practice that evolved from high-frequency trading, benefits only a select few sophisticated traders and institutions with the resources necessary to view and respond to flashed orders. This practice undermines the basic principles of fairness and transparency in securities regulation, exacerbates information asymmetries and harms investor confidence. This iBrief revisits the Securities and Exchange Commission\u27s proposed ban on the controversial practice of flash trading and urges the Securities and Exchange Commission and the Commodity Futures Trading Commission to implement the ban across the securities and futures markets. Banning flash trading will not impact high-frequency trading or other advantageous innovative trading practices, and will benefit all market participants by making prices and liquidity more transparent. In the wake of the May 6, 2010 flash crash and the passage of the Dodd-Frank Wall Street Reform and Consumer Protection Act, now is an opportune time for the Securities and Exchange Commission and Commodity Futures Trading Commission to implement the ban

    Meat Consumption Patterns and Intentions for Change Among Finnish Consumers

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    During the past few decades, meat has increasingly become a subject of controversies relating to health and safety, environment, and animal welfare. Even though these changes in perceptions of meat are not yet visible in aggregate consumption figures, they can be observed in individual consumption patterns and as intentions to change the consumption. In this study, we examine changes in meat consumption among the Finnish consumers taking into account both stated changes in the past and intended changes in the future. Based on these changes, we identify consumer segments and investigate in which ways these segments differ from each other socio-demographically and with respect to current meat consumption and the stated reasons for the change. The latent class analysis based on representative Internet survey data revealed nine consumer clusters that formed three cluster blocks. The results showed that a large number of people, over 40%, had stabile consumption patterns. A cluster block of 14% of consumers had already shifted their consumer patterns to contain more vegetables and less meat. One third of the consumers were identified to be in the middle of the change with a general tendency to decrease the use of meat and increase the use of vegetables. Although, environmental effects of meat and animal welfare issues were important reasons for change in some clusters, healthiness was the most salient stated reason for change in consumption habits.Food Consumption/Nutrition/Food Safety, Livestock Production/Industries,

    Population trends in northern spotted owls: Associations with climate in the Pacific Northwest

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    We used reverse time capture-mark-recapture models to describe associations between rate of population change (λ) and climate for northern spotted owls (Strix occidentalis caurina) at six long-term study areas in Washington and Oregon, USA. Populations in three of six areas showed strong evidence of declining populations, while populations in two additional areas were likely declining as well. At four areas, λ was positively associated with wetter-than-normal conditions during the growing season, which likely affects prey availability. Lambda was also negatively associated with cold, wet winters and nesting seasons, and the number of hot summer days. The amount of annual variation in λ accounted for by climate varied across study areas (3–85%). Rate of population change was more sensitive to adult survival than to recruitment; however, there was considerable variation among years and across study areas for all demographic rates. While annual survival was more closely related to regional climate conditions, recruitment was often associated with local weather. In addition to climate, declines in recruitment at four of six areas were associated with increased presence of barred owls. Climate change models predict warmer, wetter winters and hotter, drier summers for the Pacific Northwest in the first half of the 21st century. Our results indicate that these conditions have the potential to negatively affect annual survival, recruitment, and consequently population growth rates for northern spotted owls

    Diversity and Relatedness Enhance Survival in Colour Polymorphic Grasshoppers

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    Evolutionary theory predicts that different resource utilization and behaviour by alternative phenotypes may reduce competition and enhance productivity and individual performance in polymorphic, as compared with monomorphic, groups of individuals. However, firm evidence that members of more heterogeneous groups benefit from enhanced survival has been scarce or lacking. Furthermore, benefits associated with phenotypic diversity may be counterbalanced by costs mediated by reduced relatedness, since closely related individuals typically are more similar. Pygmy grasshoppers (Tetrix subulata) are characterized by extensive polymorphism in colour pattern, morphology, behaviour and physiology. We studied experimental groups founded by different numbers of mothers and found that survival was higher in low than in high density, that survival peaked at intermediate colour morph diversity in high density, and that survival was independent of diversity in low density where competition was less intense. We further demonstrate that survival was enhanced by relatedness, as expected if antagonistic and competitive interactions are discriminately directed towards non-siblings. We therefore also performed behavioural observations and staged encounters which confirmed that individuals recognized and responded differently to siblings than to non-siblings. We conclude that negative effects associated with competition are less manifest in diverse groups, that there is conflicting selection for and against genetic diversity occurring simultaneously, and that diversity and relatedness may facilitate the productivity and ecological success of groups of interacting individuals

    A possible revival of population-representing digital human manikins in static work situations - exemplified through an evaluation of a prototype console for robotic surgery

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    BACKGROUND: In the 90s, digital human manikins (DHMs) were introduced in planning ofworkstations, by static or semi-static simulations. Modern DHMs can simulate dynamic work and offer a rapid way for a virtual pre-production ergonomic evaluation. Work-related musculoskeletal disorders may affect surgical performance and patient safety. A prototype of an open console, which is contrary to the conventional closed consoles and may be seen as a representative for a new generation, has been designed to reduce workload for robotic surgery surgeons. OBJECTIVE: The aim of this project was to test a new DHM tool with improved usability to evaluate the ergonomics of a console of a robotic surgical system in a pre-production stage. METHODS: The DHM tool IMMA was used together with a 3D model of the prototype console. Twelve manikins who represented females and males from two national populations were introduced. Manikin-console distances, after console adjustments per manikin, were compared with a US checklist and Swedish standard for VDU work. RESULTS: The DHM tool was useful for this case, but the distances of the checklist and the standard were needed to be obtained "manually". The automatic functions of the DHM worked smoothly but were not optimized for VDU work. The prototype fulfilled most, but not all, of the ergonomic criteria of the checklist and the standard. CONCLUSIONS: There is room for improvements of the adjustable ranges of the console prototype. DHMs may facilitate rapid pre-production evaluation of workstations for static work; if ergonomic assessment models for VDU work are built-in, there may be a revival of DHMs in static work situations

    Effects of sensor types and angular velocity computational methods in field measurements of occupational upper arm and trunk postures and movements

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    Accelerometer-based inclinometers have dominated kinematic measurements in previous field studies, while the use of inertial measurement units that additionally include gyroscopes is rapidly increasing. Recent laboratory studies suggest that these two sensor types and the two commonly used angular velocity computational methods may produce substantially different results. The aim of this study was, therefore, to evaluate the effects of sensor types and angular velocity computational methods on the measures of work postures and movements in a real occupational setting. Half-workday recordings of arm and trunk postures, and movements from 38 warehouse workers were compared using two sensor types: accelerometers versus accelerometers with gyroscopes—and using two angular velocity computational methods, i.e., inclination velocity versus generalized velocity. The results showed an overall small difference (<2\ub0 and value independent) for posture percentiles between the two sensor types, but substantial differences in movement percentiles both between the sensor types and between the angular computational methods. For example, the group mean of the 50th percentiles were for accelerometers: 71\ub0/s (generalized velocity) and 33\ub0/s (inclination velocity)—and for accelerometers with gyroscopes: 31\ub0/s (generalized velocity) and 16\ub0/s (inclination velocity). The significant effects of sensor types and angular computational methods on angular velocity measures in field work are important in inter-study comparisons and in comparisons to recommended threshold limit values
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