588 research outputs found

    Dispersive effects in neutron matter superfluidity

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    The explicit energy dependence of the single particle self-energy (dispersive effects), due to short range correlations, is included in the treatment of neutron matter superfluidity. The method can be applied in general to strong interacting fermion systems, and it is expected to be valid whenever the pairing gap is substantially smaller than the Fermi kinetic energy. The results for neutron matter show that dispersive effects are strong in the density region near the gap closure.Comment: 9 pages, 4 ps figure

    Baltic Ecological Recycling Agriculture and Society (BERAS project) - a case of Juva milk system

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    The aim of the study was to determine the potential, impact and prerequisites of localization and enhanced recycling in a rural food system, illustrated by the case of Juva milk. An interdisciplinary scenario based on the increase of local, organic milk to 50 % of milk comsumption was created and the sustainability was compared, on the basis of the statistics and data collected from the actors, with the present milk system

    Can ICU admission be predicted?

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    After intensive care (IC), patients report poor health-related quality of life (HRQoL). Many factors affect the patients and influence the HRQoL after discharge. One of these factors is the patient's health status before the critical care period. In a previous study we found that the IC patients have a high frequency of pre-existing diseases. However, it is unknown to what extent these pre-existing diseases affect the consumption of hospital resources (measured as days as inpatients) in the time period before admission to the ICU and during the years following it. The consumption prior to the ICU event may also be claimed to herald an increased risk for a later ICU admittance? The aim of this study was to examine the hospital care consumption of former ICU patients 3 years prior to and 3 years after the intensive care period. This was examined in relation to the pre-existing health status

    Automatic memory processes in normal ageing and Alzheimer’s disease

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    This study examined the contribution of automatic and controlled uses of memory to stem completion in young, middle-aged and older adults, and compared these data with a study involving patients with Alzheimer’s disease (AD) who performed the same task (Hudson and Robertson, 2007). In an inclusion task participants aimed to complete three-letter word stems with a previously studied word, in an exclusion task the aim was to avoid using studied words to complete stems. Performances under inclusion and exclusion conditions were contrasted to obtain estimates of controlled and automatic memory processes using process-dissociation calculations (Jacoby, 1991). An age-related decline, evident from middle age was observed for the estimate of controlled processing, whereas the estimate of automatic processing remained invariant across the age groups. This pattern stands in contrast to what is observed in AD, where both controlled and automatic processes have been shown to be impaired. Therefore, the impairment in memory processing on stem completion that is found in AD is qualitatively different from that observed in normal ageing

    Cognitive and neural plasticity in aging: General and task-specific limitations

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    There is evidence for cognitive as well as neural plasticity across the adult life span, although aging is associated with certain constraints on plasticity. In the current paper, we argue that the age-related reduction in cognitive plasticity may be due to (a) deficits in general processing resources, and (b) failure to engage in task-relevant cognitive operations. Memory-training research suggests that age-related processing deficits (e.g., executive functions, speed) hinder older adults from utilizing mnemonic techniques as efficiently as the young, and that this age difference is reflected by diminished frontal activity during mnemonic use. Additional constraints on memory plasticity in old age are related to difficulties that are specific to the task, such as creating visual images, as well as in binding together the information to be remembered. These deficiencies are paralleled by reduced activity in occipito-parietal and medial–temporal regions, respectively. Future attempts to optimize intervention-related gains in old age should consider targeting both general processing and task-specific origins of age-associated reductions in cognitive plasticity

    Lower baseline performance but greater plasticity of working memory for carriers of the val allele of the COMT Val158Met polymorphism

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    Objective: Little is known about genetic contributions to individual differences in cognitive plasticity. Given that the neurotransmitter dopamine is critical for cognition and associated with cognitive plasticity, we investigated the effects of 3 polymorphisms of dopamine-related genes (LMX1A, DRD2, COMT) on baseline performance and plasticity of working memory (WM), perceptual speed, and reasoning. Method: One hundred one younger and 103 older adults underwent approximately 100 days of cognitive training, and extensive testing before and after training. We analyzed the baseline and posttest data using latent change score models. Results: For working memory, carriers of the val allele of the COMT polymorphism had lower baseline performance and larger performance gains from training than carriers of the met allele. There was no significant effect of the other genes or on other cognitive domains. Conclusions: We relate this result to available evidence indicating that met carriers perform better than val carriers in WM tasks taxing maintenance, whereas val carriers perform better at updating tasks. We suggest that val carriers may show larger training gains because updating operations carry greater potential for plasticity than maintenance operations. (DIPF/Orig.

    Technical, Economic and Allocative Efficiency of Microfinance Borrowers and Non-Borrowers : Evidence from Peasant Farming in Bangladesh

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    This paper empirically examines the technical, economic and allocative efficiency of agricultural microfinance borrowers and non-borrowers in rice farming in Bangladesh using Data Envelopment Analysis (DEA) of survey data obtained in 2009. Inefficiency effects are modeled as a function of farm–specific and institutional variables. The mean technical, allocative, and economic efficiencies are found to be 72%, 66%, and 47 % respectively in the pooled sample under variable returns to scale specification. This indicates the existence of substantial gains in output and/or decreases in cost in the study areas. Results reveal that after effectively correcting for sample selection bias, land fragmentation, family size, household wealth, on farm-training and off–farm income share are the main determinants of inefficiency. Efficiency scores between microfinance borrowers and non–borrowers are significantly different which are also conformed by the non–discretionary DEA model. This study also revealed that excess costs owing to inefficiencies was 53% and concludes that main challenge facing the rice farmers in Bangladesh is to develop their cost minimizing skills. Some indicative policy guidelines to improve efficiencies are also suggested.Peer reviewe

    Long-term fertilizer field trials: comparison of three mathematical response models

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    Accession to the European Union caused a drop of nearly 60 per cent from 1994 to 1995 in prices of wheat, barley and oats in Finland. The economic use of fertilizer therefore decreased accordingly. To calculate the effect of the price changes on the economic optima, the physical production function must be known. Three physical production functions, the quadratic, the linear response and plateau (LRP) and the exponential function were estimated for this purpose. The models differed little in respect of the R2adj value (0.82-0.90) but the calculated optimum varied, depending on the production function. Data on a long-term field trial (21 years) were analysed. The field trial was established in 1973 to demonstrate the effect of mineral fertilizer in crop production. The crops grown in the trial were barley, wheat and oats. Different varieties were included in the models

    Continuum quasiparticle random phase approximation and the time dependent Hartree-Fock-Bogoliubov approach

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    Quadrupole excitations of neutron-rich nuclei are analyzed by using the linear response method in the Quasiparticle Random Phase Approximation (QRPA). The QRPA response is derived starting from the time-dependent Hartree-Fock-Bogoliubov (HFB) equations. The residual interaction between the quasiparticles is determined consistently from the two-body force used in the HFB equations, and the continuum coupling is treated exactly. Calculations are done for the neutron-rich oxygen isotopes. It is found that pairing correlations affect the low-lying states, and that a full treatment of the continuum can change the structure of the states in the giant resonance region.Comment: 17 pages, 7 figures. Revised version with comments and references adde
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