608 research outputs found

    Some properties of the k-dimensional Lyness' map

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    This paper is devoted to study some properties of the k-dimensional Lyness' map. Our main result presentes a rational vector field that gives a Lie symmetry for F. This vector field is used, for k less or equal to 5 to give information about the nature of the invariant sets under F. When k is odd, we also present a new (as far as we know) first integral for F^2 which allows to deduce in a very simple way several properties of the dynamical system generated by F. In particular for this case we prove that, except on a given codimension one algebraic set, none of the positive initial conditions can be a periodic point of odd period.Comment: 22 pages; 3 figure

    Non-autonomous 2-periodic Gumovski-Mira difference equations

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    We consider two types of non-autonomous 2-periodic Gumovski-Mira difference equations. We show that while the corresponding autonomous recurrences are conjugated, the behavior of the sequences generated by the 2-periodic ones differ dramatically: in one case the behavior of the sequences is simple (integrable) and in the other case it is much more complicated (chaotic). We also present a global study of the integrable case that includes which periods appear for the recurrence.Comment: 20 pages, 11 figure

    Health and lifestyle of Nepalese migrants in the UK

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    Background: The health status and lifestyle of migrants is often poorer than that of the general population of their host countries. The Nepalese represent a relatively small, but growing, immigrant community in the UK, about whom very little is known in term of public health. Therefore, our study examined the health and lifestyle of Nepalese migrants in the UK. Methods: A cross-sectional survey of Nepalese migrants in UK was conducted in early 2007 using a postal, self-administered questionnaire in England and Scotland (n = 312), and telephone interviews in Wales (n = 15). The total response rate was 68% (327 out of 480). Data were analyzed to establish whether there are associations between socio-economic and lifestyle factors. A multivariate binary logistic regression was applied to find out independent effect of personal factors on health status. Results: The majority of respondents was male (75%), aged between 30 and 45 (66%), married or had a civil partner (83%), had university education (47%) and an annual family income (69%) ranging from £5,035 to £33,300. More than one third (39%) of the respondents have lived in the UK for 1 to 5 years and approximately half (46%) were longer-term residents. Most (95%) were registered with a family doctor, but only 38% with a dentist. A low proportion (14%) of respondents smoked but more than half (61%) consumed alcohol. More than half (57%) did not do regular exercises and nearly one fourth (23%) of respondents rated their health as poor. Self reported 'good' health status of the respondents was independently associated with immigration status and doing regular exercise Conclusion: The self reported health status and lifestyle, health seeking behaviour of Nepalese people who are residing in UK appears to be good. However, the overall regular exercise and dentist registration was rather poor. Health promotion, especially aimed at Nepalese migrants could help encourage them to exercise regularly and assist them to register with a dentist

    Global behavior of solutions to the static spherically symmetric EYM equations

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    The set of all possible spherically symmetric magnetic static Einstein-Yang-Mills field equations for an arbitrary compact semi-simple gauge group GG was classified in two previous papers. Local analytic solutions near the center and a black hole horizon as well as those that are analytic and bounded near infinity were shown to exist. Some globally bounded solutions are also known to exist because they can be obtained by embedding solutions for the G=SU(2)G=SU(2) case which is well understood. Here we derive some asymptotic properties of an arbitrary global solution, namely one that exists locally near a radial value r0r_{0}, has positive mass m(r)m(r) at r0r_{0} and develops no horizon for all r>r0r>r_{0}. The set of asymptotic values of the Yang-Mills potential (in a suitable well defined gauge) is shown to be finite in the so-called regular case, but may form a more complicated real variety for models obtained from irregular rotation group actions.Comment: 43 page

    Does plant diversity affect the water balance of established grassland systems like in manipulative biodiversity experiments?

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    Land-use intensification and biodiversity loss are known drivers of the water cycle but their interactions are unclear. We investigated how evapotranspiration (ETa), downward water flux (DF), and capillary rise (CR) in topsoil and subsoil are related to land-use and plant diversity in established, commercially managed grassland and compared these results to findings from an experiment in which plant diversity was manipulated. In three Central European regions (“Biodiversity Exploratories”), we studied 29 grassland plots (50 m x 50 m; 9-11 plots per region). Land-use intensity increases in the order, pasture < mown pasture < meadow. In 2010-2015, we measured soil moisture, meteorological conditions, plant species richness, number of species in the functional groups of grasses, herbs, and legumes, and root biomass. ETa, DF, and CR were calculated for two soil layers with a soil water balance model. Land-use and biodiversity effects on water fluxes were analyzed with repeated-measures analysis of variance. Land-use intensity did not affect water fluxes. Species richness did not influence DF and CR. ETa from topsoil decreased with increasing species richness while ETa from subsoil increased. Opposing effects on ETa in the two soil layers were also observed for the number of herbs and legumes. In manipulative biodiversity experiments, such opposing effects were explained by higher biomass in species-rich mixtures, which increases shading of topsoil and reduces evaporation. In subsoil, deeper roots in species-rich mixtures increased transpiration. In the commercially managed grasslands, biomass and species richness correlated negatively because fertilizer application increased biomass and decreased species richness. Thus, similar effects of biodiversity on water fluxes in commercially managed and experimentally manipulated grassland had different reasons. We speculate that improved infiltration and enhanced bioturbation in species-rich grassland explained our observations

    Expression of an S phase-stabilized version of the CDK inhibitor Dacapo can alter endoreplication

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    In developing organisms, divergence from the canonical cell division cycle is often necessary to ensure the proper growth, differentiation, and physiological function of a variety of tissues. An important example is endoreplication, in which endocycling cells alternate between G and S phase without intervening mitosis or cytokinesis, resulting in polyploidy. Although significantly different from the canonical cell cycle, endocycles use regulatory pathways that also function in diploid cells, particularly those involved in S phase entry and progression. A key S phase regulator is the Cyclin E-Cdk2 kinase, which must alternate between periods of high (S phase) and low (G phase) activity in order for endocycling cells to achieve repeated rounds of S phase and polyploidy. The mechanisms that drive these oscillations of Cyclin E-Cdk2 activity are not fully understood. Here, we show that the Drosophila Cyclin E-Cdk2 inhibitor Dacapo (Dap) is targeted for destruction during S phase via a PIP degron, contributing to oscillations of Dap protein accumulation during both mitotic cycles and endocycles. Expression of a PIP degron mutant Dap attenuates endocycle progression but does not obviously affect proliferating diploid cells. A mathematical model of the endocycle predicts that the rate of destruction of Dap during S phase modulates the endocycle by regulating the length of G phase. We propose from this model and our in vivo data that endo S phase-coupled destruction of Dap reduces the threshold of Cyclin E-Cdk2 activity necessary to trigger the subsequent G-S transition, thereby influencing endocycle oscillation frequency and the extent of polyploidy

    The IDEAL (Insulin therapy DE-intensificAtion with iglarLixi) randomised controlled trial—study design and protocol

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    Introduction Multiple daily injection insulin regimen (MDI) represents the most intensive insulin regimen used in the management of people with type 2 diabetes (PwT2D). Its efficacy regarding glycaemic control is counterbalanced by the increased risk of hypoglycaemia, frequently observed tendency to weight gain and necessity for frequent glucose monitoring. Recent introduction of novel antidiabetic medications with pleiotropic effects reaching far beyond the reduction of glycaemia (HbA1c), such as the glucagon-like peptide 1 receptor agonist (GLP-1 RA), has significantly widened the therapeutic options available for management of T2D. Consequently, there is currently a substantial number of PwT2D for whom the MDI regimen was initiated at a time when no other options were available. Yet, in present times, these individuals could benefit from simplified insulin regimens ideally taking advantage of the beneficial effects of the novel classes of antidiabetic medications. iGlarLixi (Suliqua®) is a once-daily fixed-ratio combination of basal insulin analogue glargine 100 U/ml and a GLP-1 RA lixisenatide. Methods Insulin therapy DE-intensificAtion with iglarLixi (IDEAL) is a six-centre, open-label, parallel-group, active comparator, phase IV randomised controlled trial with a 24-week active treatment period examining the efficacy and safety of MDI regimen de-intensification with once-daily administration of iGlarLixi versus MDI regimen continuation in PwT2D on a backgroud therapy with metformin ± sodium-glucose cotransporter 2 inhibitor. Planned Outcomes The primary objective is to compare the effects of MDI therapy de-intensification with iGlarLixi versus MDI regimen continuation regarding glycaemic control (HbA1c). Secondary objectives include detailed evaluation of the effects of MDI regimen de-intensification with iGlarLixi on glycaemic control using standardised continuous glucose monitoring (CGM) metrics and self-monitoring of plasma glucose. Furthermore, body weight and body composition analysis, quality of life and safety profile are evaluated. Trial Registration ClinicalTrials.gov, identifier NCT04945070

    The Influence of Mirror-Visual Feedback on Training-Induced Motor Performance Gains in the Untrained Hand

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    The well-documented observation of bilateral performance gains following unilateral motor training, a phenomenon known as cross-limb transfer, has important implications for rehabilitation. It has recently been shown that provision of a mirror image of the active hand during unilateral motor training has the capacity to enhance the efficacy of this phenomenon when compared to training without augmented visual feedback (i.e., watching the passive hand), possibly via action observation effects [1]. The current experiment was designed to confirm whether mirror-visual feedback (MVF) during motor training can indeed elicit greater performance gains in the untrained hand compared to more standard visual feedback (i.e., watching the active hand). Furthermore, discussing the mechanisms underlying any such MVF-induced behavioural effects, we suggest that action observation and the cross-activation hypothesis may both play important roles in eliciting cross-limb transfer. Eighty participants practiced a fast-as-possible two-ball rotation task with their dominant hand. During training, three different groups were provided with concurrent visual feedback of the active hand, inactive hand or a mirror image of the active hand with a fourth control group receiving no training. Pre- and post-training performance was measured in both hands. MVF did not increase the extent of training-induced performance changes in the untrained hand following unilateral training above and beyond those observed for other types of feedback. The data are consistent with the notion that cross-limb transfer, when combined with MVF, is mediated by cross-activation with action observation playing a less unique role than previously suggested. Further research is needed to replicate the current and previous studies to determine the clinical relevance and potential benefits of MVF for cases that, due to the severity of impairment, rely on unilateral training programmes of the unaffected limb to drive changes in the contralateral affected limb
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