843 research outputs found

    IMPACTS OF POLICY REFORM ON SUSTAINABILITY OF HILL FARMING IN UK BY MEANS OF BIO-ECONOMIC MODELLING

    Get PDF
    Hill farming in UK is experiencing very difficult economic circumstances and many farmers rely on subsidies provided by the government for a large fraction of their income. The Peak District National Park is used as a case study to examine how farmers might respond to current policy changes � in particular, the move from area- and headage-based payments to the Single Farm Payment, and how optimal business plans should respond to these changes. The objective of this paper is thus to develop production models that predict how farmers will respond to changing policy framework conditions. For this purpose socio-economic surveys were carried out on 44 sample farms, in order to investigate how the land is managed on hill farms including ongoing policies and future farm management planning. Based on these surveys a series of representative farm linear programming models was developed, which represent typical farm types in the uplands in the Peak District. In this study the focus is on typical sheep and beef farm type, the most common in this region. This model is used to calculate the effect of different policies, carried out under CAP reform, on incomes, land use and the intensity of production. We also consider the impacts of a complete removal of subsidy.CAP reform, Single Farm Payment, hill farming, linear programming model, Agricultural and Food Policy, Crop Production/Industries, Farm Management, Land Economics/Use,

    Multi-mode coupling wave theory for helically corrugated waveguide

    Get PDF
    Helically corrugated waveguide has been used in various applications such as gyro-backward wave oscillators, gyro-traveling wave amplifier and microwave pulse compressor. A fast prediction of the dispersion characteristic of the operating eigenwave is very important when designing a helically corrugated waveguide. In this paper, multi-mode coupling wave equations were developed based on the perturbation method. This method was then used to analyze a five-fold helically corrugated waveguide used for X-band microwave compression. The calculated result from this analysis was found to be in excellent agreement with the results from numerical simulation using CST Microwave Studio and vector network analyzer measurements

    The effect of decoupling on marginal agricultural systems: implications for farm incomes, land use and upland ecology

    Get PDF
    In many parts of Europe, decades of production subsidies led to the steady intensification of agriculture in marginal areas, but the recent decoupling of subsidies from production decisions means that the future of farming in these areas is uncertain. For example, in the uplands of the United Kingdom, an area important both for biodiversity conservation and ecosystem service provision, hill farmers steadily increased stocking densities in response to headage payments but must now reconfigure farm businesses to account for the shift to the Single Farm Payment scheme. We examined hill farming in the Peak District National Park as a case study into the future of marginal agriculture after decoupling. We surveyed 44 farm businesses and from this identified six representative farm types based on enterprise mix and land holdings. We developed linear programming models of production decisions for each farm type to examine the impacts of policy changes, comparing the effects of decoupling with and without agri-environment and hill farm support, and evaluating the effects of removal of the Single Farm Payment. The main effects of decoupling are to reduce stocking rates, and to change the mix of livestock activities. Agri-environmental schemes mediate the income losses from decoupling, and farmers are predicted to maximise take up of new Environmental Stewardship programmes, which have both positive and negative feedback effects on livestock numbers. Finally, removal of the Single Farm Payment would lead to negative net farm incomes, and some land abandonment. These changes have important implications for ongoing debates about how ecological service flows can be maintained from upland areas, and how marginal upland farming communities can be sustained

    Aberrant Neuronal Dynamics during Working Memory Operations in the Aging HIV-Infected Brain

    Get PDF
    Impairments in working memory are among the most prevalent features of HIV-associated neurocognitive disorders (HAND), yet their origins are unknown, with some studies arguing that encoding operations are disturbed and others supporting deficits in memory maintenance. The current investigation directly addresses this issue by using a dynamic mapping approach to identify when and where processing in working memory circuits degrades. HIV-infected older adults and a demographically-matched group of uninfected controls performed a verbal working memory task during magnetoencephalography (MEG). Significant oscillatory neural responses were imaged using a beamforming approach to illuminate the spatiotemporal dynamics of neuronal activity. HIV-infected patients were significantly less accurate on the working memory task and their neuronal dynamics indicated that encoding operations were preserved, while memory maintenance processes were abnormal. Specifically, no group differences were detected during the encoding period, yet dysfunction in occipital, fronto-temporal, hippocampal, and cerebellar cortices emerged during memory maintenance. In addition, task performance in the controls covaried with occipital alpha synchronization and activity in right prefrontal cortices. In conclusion, working memory impairments are common and significantly impact the daily functioning and independence of HIV-infected patients. These impairments likely reflect deficits in the maintenance of memory representations, not failures to adequately encode stimuli

    Aberrant Neuronal Dynamics during Working Memory Operations in the Aging HIV-Infected Brain.

    Get PDF
    Impairments in working memory are among the most prevalent features of HIV-associated neurocognitive disorders (HAND), yet their origins are unknown, with some studies arguing that encoding operations are disturbed and others supporting deficits in memory maintenance. The current investigation directly addresses this issue by using a dynamic mapping approach to identify when and where processing in working memory circuits degrades. HIV-infected older adults and a demographically-matched group of uninfected controls performed a verbal working memory task during magnetoencephalography (MEG). Significant oscillatory neural responses were imaged using a beamforming approach to illuminate the spatiotemporal dynamics of neuronal activity. HIV-infected patients were significantly less accurate on the working memory task and their neuronal dynamics indicated that encoding operations were preserved, while memory maintenance processes were abnormal. Specifically, no group differences were detected during the encoding period, yet dysfunction in occipital, fronto-temporal, hippocampal, and cerebellar cortices emerged during memory maintenance. In addition, task performance in the controls covaried with occipital alpha synchronization and activity in right prefrontal cortices. In conclusion, working memory impairments are common and significantly impact the daily functioning and independence of HIV-infected patients. These impairments likely reflect deficits in the maintenance of memory representations, not failures to adequately encode stimuli

    Is Socioeconomic Status of the Rearing Environment Causally Related to Obesity in the Offspring?

    Get PDF
    We attempt to elucidate whether there might be a causal connection between the socioeconomic status (SES) of the rearing environment and obesity in the offspring using data from two large-scale adoption studies: (1) The Copenhagen Adoption Study of Obesity (CASO), and (2) The Survey of Holt Adoptees and Their Families (HOLT). In CASO, the SES of both biological and adoptive parents was known, but all children were adopted. In HOLT, only the SES of the rearing parents was known, but the children could be either biological or adopted. After controlling for relevant covariates (e.g., adoptee age at measurement, adoptee age at transfer, adoptee sex) the raw (unstandardized) regression coefficients for adoptive and biological paternal SES on adoptee body mass index (BMI: kg/m2) in CASO were -.22 and -.23, respectively, both statistically significant (p = 0.01). Controlling for parental BMI (both adoptive and biological) reduced the coefficient for biological paternal SES by 44% (p = .034) and the coefficient for adoptive paternal SES by 1%. For HOLT, the regression coefficients for rearing parent SES were -.42 and -.25 for biological and adoptive children, respectively. Controlling for the average BMI of the rearing father and mother (i.e., mid-parental BMI) reduced the SES coefficient by 47% in their biological offspring (p≤.0001), and by 12% in their adoptive offspring (p = .09). Thus, despite the differing structures of the two adoption studies, both suggest that shared genetic diathesis and direct environmental transmission contribute about equally to the association between rearing SES and offspring BMI

    The development of emotion regulation: an fMRI study of cognitive reappraisal in children, adolescents and young adults

    Get PDF
    The ability to use cognitive reappraisal to regulate emotions is an adaptive skill in adulthood, but little is known about its development. Because reappraisal is thought to be supported by linearly developing prefrontal regions, one prediction is that reappraisal ability develops linearly. However, recent investigations into socio-emotional development suggest that there are non-linear patterns that uniquely affect adolescents. We compared older children (10–13), adolescents (14–17) and young adults (18–22) on a task that distinguishes negative emotional reactivity from reappraisal ability. Behaviorally, we observed no age differences in self-reported emotional reactivity, but linear and quadratic relationships between reappraisal ability and age. Neurally, we observed linear age-related increases in activation in the left ventrolateral prefrontal cortex, previously identified in adult reappraisal. We observed a quadratic pattern of activation with age in regions associated with social cognitive processes like mental state attribution (medial prefrontal cortex, posterior cingulate cortex, anterior temporal cortex). In these regions, we observed relatively lower reactivity-related activation in adolescents, but higher reappraisal-related activation. This suggests that (i) engagement of the cognitive control components of reappraisal increases linearly with age and (ii) adolescents may not normally recruit regions associated with mental state attribution, but (iii) this can be reversed with reappraisal instructions.National Science Foundation (U.S.) (Grant BCS-0224342

    Better quality of life with neuropsychological improvement on HAART

    Get PDF
    Abstract: Background: Successful highly active antiretroviral therapy (HAART) regimens have resulted in substantial improvements in the systemic health of HIV infected persons and increased survival times. Despite increased systemic health, the prevalence of minor HIV-associated cognitive impairment appears to be rising with increased longevity, and it remains to be seen what functional outcomes will result from these improvements. Cognitive impairment can dramatically impact functional ability and day-to-day productivity. We assessed the relationship of quality of life (QOL) and neuropsychological functioning with successful HAART treatment. Methods: In a prospective longitudinal study, subjects were evaluated before instituting HAART (naïve) or before changing HAART regimens because current therapy failed to maintain suppression of plasma viral load (treatment failure). Subjects underwent detailed neuropsychological and neurological examinations, as well as psychological evaluation sensitive to possible confounds. Re-evaluation was performed six months after institution of the new HAART regimen and/or if plasma viral load indicated treatment failure. At each evaluation, subjects underwent ultrasensitive HIV RNA quantitative evaluation in both plasma and cerebrospinal fluid. Results: HAART successes performed better than failures on measures exploring speed of mental processing (p < .02). HAART failure was significantly associated with increased self-reports of physical health complaints (p < .01) and substance abuse (p < .01). An interesting trend emerged, in which HAART failures endorsed greater levels of psychological and cognitive complaints (p = .06). Analysis between neuropsychological measures and QOL scores revealed significant correlation between QOL Total and processing speed (p < .05), as well as flexibility (p < .05). Conclusion: Our study investigated the relationship between HIV-associated neurocognitive impairment and quality of life. HAART failures experienced slower psychomotor processing, and had increased self-reports of physical health complaints and substance abuse. Contrariwise, HAART successes experienced improved mental processing, demonstrating the impact of successful treatment on functioning. With increasing life expectancy for those who are HIV seropositive, it is important to measure cognitive functioning in relation to the actual QOL these individuals report. The study results have implications for the optimal management of HIV-infected persons. Specific support or intervention may be beneficial for those who have failed HAART in order to decrease substance abuse and increase overall physical health

    Independent effects of HIV infection and cocaine dependence on neurocognitive impairment in a community sample living in the southern United States

    Get PDF
    Prior studies have established that methamphetamine and HIV can have additive deleterious effects on neurocognitive functioning, but there has been relatively little research on other stimulants like cocaine. This study investigated the effects of cocaine and HIV on neurocognitive impairment in a large, well-characterized sample
    corecore