411 research outputs found

    Price and tax policy for semi-subsistence agriculture in Ethiopia

    Get PDF
    In the case of semi-subsistence agriculture where wage employment is not available, the role played by prices and taxes in determining production and consumption decisions is not clearly established by economic theories of household choice. This study demonstrates that where choices in production, consumption, and leisure can be made independently, farmers will decide what to grow on the basis of their preferences for marketed goods. The paper also points out that the choice will be affected by the level and type of taxation imposed. The paper shows the impact of four taxes -- agricultural revenue, land, production and marketed goods consumption -- on crop production and tax revenues. This paper also reports on a model of production in Ethiopia. The results of this study give strong evidence of the role of producer and consumer prices in semi-subsistence agriculture. In addition, the results show the importance of production capacity, household and climatic factors in agricultural development.Environmental Economics&Policies,Economic Theory&Research,Crops&Crop Management Systems,Agricultural Knowledge&Information Systems,Consumption

    Constriction size distributions of granular filters: a numerical study

    Get PDF
    The retention capability of granular filters is controlled by the narrow constrictions connecting the voids within the filter. The theoretical justification for empirical filter rules used in practice includes consideration of an idealised soil fabric in which constrictions form between co-planar combinations of spherical filter particles. This idealised fabric has not been confirmed by experimental or numerical observations of real constrictions. This paper reports the results of direct, particle-scale measurement of the constriction size distribution (CSD) within virtual samples of granular filters created using the discrete-element method (DEM). A previously proposed analytical method that predicts the full CSD using inscribed circles to estimate constriction sizes is found to poorly predict the CSD for widely graded filters due to an over-idealisation of the soil fabric. The DEM data generated are used to explore quantitatively the influence of the coefficient of uniformity, particle size distribution and relative density of the filter on the CSD. For a given relative density CSDs form a narrow band of similarly shaped curves when normalised by characteristic filter diameters. This lends support to the practical use of characteristic diameters to assess filter retention capability

    The Temporary Staffing Industry in Protected Employment Economies: Germany, Japan and the Netherlands

    Get PDF
    The paper addresses how the temporary staffing industry secures social security and a degree of employment stability in three non-liberal market economies with a well developed temp work sector and several decades of industry regulation. Until the 1980s unions in Germany, Japan and the Netherlands effectively opposed the deregulation of the staffing industry. Restrictions placed on the temporary staffing industry institutionalized an “employment-type” alternative to the US-style form of “registered” and “on-call” temp staffing. In the face of high unemployment in the 1990s unions participated in de-regulatory drives aimed at expanding the role of the industry in troubled national labor markets. In most cases, de-regulation dismantled key dimensions of the “employment type” of staffing, and unions shifted their efforts to securing equal treatment of temporary staff. To date, legislation has fallen short of mandating equal treatment, and in the best cases (Germany and the Netherlands) collective bargaining has taken on the role of securing equal wages for temporary staff. Japan, Germany and the Netherlands represent three different degrees of industry de-regulation, with the best case of equal treatment of temps in the Netherlands, and the deepest segmentation of temporary and regular workers in Japan. In comparison to Germany and Japan, Dutch unions early on engaged in regulating temporary staffing services. The early experience of regulating rather than rejecting contingent labor and the density of neo-corporatist institutions for social bargaining in the Netherlands means that Dutch unions have developed stronger capacities for regulating contingent employment despite the weak organization of contingent workers. Unions in Japan and Germany have only recently developed capacities for representing contingent labour, but the significant weakening of social bargaining in both countries is associated with growing labor market segmentation between temporary and regular employees

    Physical Activity During the Early Years: A Systematic Review of Correlates and Determinants.

    Get PDF
    CONTEXT: Being physically active during the early years (age 0-6 years) is vital for healthy development. Identifying correlates and determinants of physical activity (PA) is crucial to guide effective interventions. This systematic review synthesized studies investigating potential correlates and determinants of PA during the early years, accounting for different types of PA assessment. EVIDENCE ACQUISITION: Nine electronic databases were searched from inception year (1900) until September 2014; data were analyzed/interpreted in April 2015. The following inclusion criteria were used: written in English, published in peer-reviewed journals, participants not in statutory/school education, and an observational design investigating associations between an exposure/variable, and a quantitative measure of PA. Correlates/determinants of total, moderate to vigorous, and light PA were reported using an ecologic model. EVIDENCE SYNTHESIS: Of 22,045 identified studies, 130 were included. All took place in high-income countries and few (6%) were of high quality. Correlates of total PA were sex (male, ++); parental PA (+); parental support (+); and time outdoors (+). Determinants of total PA were sex (+) and time spent playing with parents (+). The only correlate of moderate to vigorous PA was sex (male, ++). No determinants of moderate to vigorous or light PA were found. PA correlates/determinants were relatively consistent between objective and subjective PA measures. CONCLUSIONS: Numerous studies investigated potential correlates and determinants of PA, but overall quality was low. A small number of demographic/biological and social/cultural factors were associated with PA. There is a need for high-quality studies exploring correlates/determinants across all domains of the ecologic model

    Communication and control system for a 15-channel hermetic retinal prosthesis

    Get PDF
    A small, hermetic, wirelessly-controlled retinal prosthesis has been developed for pre-clinical studies in Yucatan minipigs. The device was attached conformally to the outside of the eye in the socket and received both power and data wirelessly from external sources. Based on the received image data, the prosthesis drove a subretinal thin-film polyimide array of sputtered iridium oxide stimulating electrodes. The implanted device included a hermetic titanium case containing a 15-channel stimulator and receiver chip and discrete circuit components. Feedthroughs in the hermetic case connected the chip to secondary power- and data-receiving coils, which coupled to corresponding external power and data coils driven by power amplifiers. Power was delivered by a 125 kHz carrier, and data were delivered by amplitude shift keying of a 15.5 MHz carrier at 100 kbps. Stimulation pulse strength, duration and frequency were programmed wirelessly from an external computer system. The final assembly was tested in vitro in physiological saline and in vivo in two minipigs for up to five and a half months by measuring stimulus artifacts generated by the implant's current drivers.United States. Dept. of Veteran AffairsUnited states. Dept. of Veterans Affairs. Boston Healthcare SystemNational Institutes of Health (U.S.)United States. Dept. of DefenseMassachusetts Lions Foundatio

    Large-scale assessment of 7-11-year-olds’ cognitive and sensorimotor function within the Born in Bradford longitudinal birth cohort study [version 2; peer review: 3 approved, 1 approved with reservations]

    Get PDF
    Background: Cognitive ability and sensorimotor function are crucial aspects of children’s development, and are associated with physical and mental health outcomes and educational attainment. This paper describes cross-sectional sensorimotor and cognitive function data collected on over 15,000 children aged 7-10 years, collected as part of the Born in Bradford (BiB) longitudinal birth-cohort study. Methodological details of the large-scale data collection process are described, along with initial analyses of the data involving the relationship between cognition/sensorimotor ability and age and task difficulty, and associations between tasks. Method: Data collection was completed in 86 schools between May 2016 and July 2019. Children were tested at school, individually, using a tablet computer with a digital stylus or finger touch for input. Assessments comprised a battery of three sensorimotor tasks (Tracking, Aiming, & Steering) and five cognitive tasks (three Working Memory tasks, Inhibition, and Processing Speed), which took approximately 40 minutes. Results: Performance improved with increasing age and decreasing task difficulty, for each task. Performance on all three sensorimotor tasks was correlated, as was performance on the three working memory tasks. In addition, performance on a composite working memory score correlated with performance on both inhibition and processing speed. Interestingly, within age-group variation was much larger than between age-group variation. Conclusions: The current project collected computerised measures of a range of cognitive and sensorimotor functions at 7-10 years of age in over 15,000 children. Performance varied as expected by age and task difficulty, and showed the predicted correlations between related tasks. Large within-age group variation highlights the need to consider the profile of individual children in studying cognitive and sensorimotor development. These data can be linked to the wider BiB dataset including measures of physical and mental health, biomarkers and genome-wide data, socio-demographic information, and routine data from local health and education services
    • 

    corecore