2,306 research outputs found

    The Change of Job Opportunities: the Role of Computerization and Institutions

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    This paper studies the pattern of job opportunities over the last two decades in European countries. We find that the share of high-skilled jobs have been expanding over time, while the share of medium- skilled jobs have been declining. These changes are in line with the US patterns and, according to the previous literature, they come from recent technological changes. However, our data show an interesting difference between the US and Europe: in Europe there is not any increase in the share of low-skilled employment. Moreover, we find that the difference between the proportion of employment hired in low-skilled and medium-skilled jobs is negatively correlated with both the unemployment rate and the degree of employment protection in the labour market. We propose a theoretical model to study the effects of a technological shock on the employment structure in a unionized economy. By accounting for the collective bargaining process, our model may fit Continental Europe better than the previous ones. We conclude that the definition of the union policy is crucial in order to explain observed cross-country heterogeneity in low-skilled employment.

    MicroRNAs in age-related diseases

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    Aging is a complex process that is linked to an increased incidence of major diseases such as cardiovascular and neurodegenerative disease, but also cancer and immune disorders. MicroRNAs (miRNAs) are small non-coding RNAs, which post-transcriptionally control gene expression by inhibiting translation or inducing degradation of targeted mRNAs. MiRNAs target up to hundreds of mRNAs, thereby modulating gene expression patterns. Many miRNAs appear to be dysregulated during cellular senescence, aging and disease. However, only few miRNAs have been so far linked to age-related changes in cellular and organ functions. The present article will discuss these findings, specifically focusing on the cardiovascular and neurological systems

    Implications of Habitat Choice for Protected Polymorphysms

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    In this paper we reexamine how heterogeneous heterogeneous environments can enable protected polymorphisms. Building on the classical models by Levene and Dempster of dispersal and selection in two habitats, we systematically investigate how the maintenance of polymorphisms is affected by (i) local versus global density regulation and (ii) constant versus variable output from habitats to the next generation. We show that, for populations capable of habitat choice, a third independent and fundamental class of models needs to be considered. It is characterized by local density regulation (like Levene's model) and variable habitat output (like Dempster's model). Our results indicate that the conditions determining whether a system allows for protected polymorphisms qualitatively differ in the presence and absence of matching habitat choice (which occurs when individuals prefer the habitat to which they are best adapted). Without such habitat choice, the salient distinction is not between local or global density regulation but rather between constant or variable habitat output. With matching habitat choice this situation is reversed. Analysis of the third class of models introduced here suggests that the joint evolution of matching habitat choice and local- adaptation polymorphism is easier than was previously understood

    Rejection of randomly coinciding events in ZnMoO4_4 scintillating bolometers

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    Random coincidence of events (particularly from two neutrino double beta decay) could be one of the main sources of background in the search for neutrinoless double beta decay with cryogenic bolometers due to their poor time resolution. Pulse-shape discrimination by using front edge analysis, mean-time and χ2\chi^2 methods was applied to discriminate randomly coinciding events in ZnMoO4_4 cryogenic scintillating bolometers. These events can be effectively rejected at the level of 99% by the analysis of the heat signals with rise-time of about 14 ms and signal-to-noise ratio of 900, and at the level of 92% by the analysis of the light signals with rise-time of about 3 ms and signal-to-noise ratio of 30, under the requirement to detect 95% of single events. These rejection efficiencies are compatible with extremely low background levels in the region of interest of neutrinoless double beta decay of 100^{100}Mo for enriched ZnMoO4_4 detectors, of the order of 10410^{-4} counts/(y keV kg). Pulse-shape parameters have been chosen on the basis of the performance of a real massive ZnMoO4_4 scintillating bolometer. Importance of the signal-to-noise ratio, correct finding of the signal start and choice of an appropriate sampling frequency are discussed

    Selective interactions between short-distance pollen and seed dispersal in self-compatible species.

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    In plants, genes may disperse through both pollen and seeds. Here we provide a first theoretical study of the mechanisms and consequences of the joint evolution of pollen and seed dispersal. We focus on hermaphroditic self-compatible species distributed in structured populations, assuming island dispersal of pollen and seeds among small patches of plants within large populations. Three traits are studied: the rate of among-patch seed dispersal, the rate of among-patch pollen dispersal, and the rate of within-patch pollen movement. We first analytically derive the evolutionary equilibrium state of each trait, dissect the pairwise selective interactions, and describe the joint three-trait evolutionary equilibrium under the cost of dispersal and kin competition. These results are then analytically and numerically extended to the case when selfed seeds suffer from depressed competitiveness (inbreeding depression, no heterosis). Finally individual-based simulations are used to account for a more realistic model of inbreeding load. Pollen movement is shown to generate opposite selection pressures on seed dispersal depending on spatial scale: within-patch pollen movement favors seed dispersal, whereas among-patch pollen dispersal inhibits seed dispersal. Seed dispersal selects for short-distance movements of pollen and it selects against long-distance dispersal. These interactions shape the joint evolution of these traits. Kin competition favors among-patch seed dispersal over among-patch pollen dispersal for low costs of within-patch pollen movement (and vice versa for significant costs of within-patch pollen movement). Inbreeding depression favors allogamy through high rates of within- and among-patch pollen movement. Surprisingly, it may select either for or against seed dispersal depending on the cost of among-patch pollen dispersal. Heterosis favors increased among-patch dispersal through pollen and seeds. But because these two stages inhibit each other, their joint evolution might lead to decreased seed dispersal in the presence of heterosis. Of crucial importance are the costs of dispersal

    Continuous atom laser with Bose-Einstein condensates involving three-body interactions

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    We demonstrate, through numerical simulations, the emission of a coherent continuous matter wave of constant amplitude from a Bose-Einstein Condensate in a shallow optical dipole trap. The process is achieved by spatial control of the variations of the scattering length along the trapping axis, including elastic three body interactions due to dipole interactions. In our approach, the outcoupling mechanism are atomic interactions and thus, the trap remains unaltered. We calculate analytically the parameters for the experimental implementation of this CW atom laser.Comment: 11 pages, 4 figure

    Rejection of randomly coinciding events in Li2_2100^{100}MoO4_4 scintillating bolometers using light detectors based on the Neganov-Luke effect

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    Random coincidences of nuclear events can be one of the main background sources in low-temperature calorimetric experiments looking for neutrinoless double-beta decay, especially in those searches based on scintillating bolometers embedding the promising double-beta candidate 100^{100}Mo, because of the relatively short half-life of the two-neutrino double-beta decay of this nucleus. We show in this work that randomly coinciding events of the two-neutrino double decay of 100^{100}Mo in enriched Li2_2100^{100}MoO4_4 detectors can be effectively discriminated by pulse-shape analysis in the light channel if the scintillating bolometer is provided with a Neganov-Luke light detector, which can improve the signal-to-noise ratio by a large factor, assumed here at the level of 750\sim 750 on the basis of preliminary experimental results obtained with these devices. The achieved pile-up rejection efficiency results in a very low contribution, of the order of 6×105\sim 6\times10^{-5} counts/(keV\cdotkg\cdoty), to the background counting rate in the region of interest for a large volume (90\sim 90 cm3^3) Li2_2100^{100}MoO4_4 detector. This background level is very encouraging in view of a possible use of the Li2_2100^{100}MoO4_4 solution for a bolometric tonne-scale next-generation experiment as that proposed in the CUPID project

    Estimates of the effect on hepatic iron of oral deferiprone compared with subcutaneous desferrioxamine for treatment of iron overload in thalassemia major: a systematic review

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    BACKGROUND: Beta thalassemia major requires regular blood transfusions and iron chelation to alleviate the harmful accumulation of iron. Evidence on the efficacy and safety of the available agents, desferrioxamine and deferiprone, is derived from small, non-comparative, heterogeneous observational studies. This evidence was reviewed to quantitatively compare the ability of these chelators to reduce hepatic iron. METHODS: The literature was searched using Medline and all reports addressing the effect of either chelator on hepatic iron were considered. Data were abstracted independently by two investigators. Analyses were performed using reported individual patient data. Hepatic iron concentrations at study end and changes over time were compared using ANCOVA, controlling for initial iron load. Differences in the proportions of patients improving were tested using χ(2). RESULTS: Eight of 11 reports identified provided patient-level data relating to 30 desferrioxamine- and 68 deferiprone-treated patients. Desferrioxamine was more likely than optimal dose deferiprone to decrease hepatic iron over the average follow-up of 45 months (odds ratio, 19.0, 95% CI, 2.4 to 151.4). The degree of improvement was also larger with desferrioxamine. CONCLUSIONS: This analysis suggests that desferrioxamine is more effective than deferiprone in lowering hepatic iron. This comparative analysis – despite its limitations – should prove beneficial to physicians faced with the challenge of selecting the optimal treatment for their patients
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