2,254 research outputs found

    Percolation for the stable marriage of Poisson and Lebesgue with random appetites

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    Let Ξ\Xi be a set of centers chosen according to a Poisson point process in Rd\mathbb R^d. Consider the allocation of Rd\mathbb R^d to Ξ\Xi which is stable in the sense of the Gale-Shapley marriage problem, with the additional feature that every center ξ∈Ξ\xi\in\Xi has a random appetite αV\alpha V, where α\alpha is a nonnegative scale constant and VV is a nonnegative random variable. Generalizing previous results by Freire, Popov and Vachkovskaia (\cite{FPV}), we show the absence of percolation when α\alpha is small enough, depending on certain characteristics of the moment of VV.Comment: 12 pages. Final versio

    Decentralization, happiness and the perception of institutions

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    This paper analyses whether the different powers and resources at the disposal of local and regional governments across Europe deliver greater satisfaction with political institutions and lead to greater personal happiness. The analysis uses microdata from the four available waves of the European social survey (2002, 2004, 2006 and 2008), including more than 160,000 observations of individuals living in 29 European countries. Our results reveal that political and fiscal decentralization have a positive and significant effect on individuals' overall happiness. Fiscal decentralization also exerts a significant effect on the level of satisfaction with political and economic institutions and with the education and health systems, whereas the effect of political decentralization on these variables is more limited. The results show that citizens seem to be happier with the actual capacity of their local governments to deliver than with the general principle that they can have a say on their daily politics and policies.Happiness; well-being; satisfaction; fiscal and political decentralization; Europe

    Temperature Drives P granule Formation in Caenorhabditis elegans

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    Ectotherms are living creatures whose body temperature varies with the environment in which they live. Their physiology and metabolism have to rapidly respond to environmental changes in order to stay viable at across their tolerable thermal range (Lithgow et al. 1994). In nematodes such as Caenorhabditis elegans, temperature is an important factor that defines the fertility of the worm. A feature that delimits an ectotherm’s thermal range is the maximum temperature at which its germ line can produce gametes. How germ cells withstand high environmental stressors such as limiting temperatures is not well understood, especially when considering the thermodynamical principles that dominate the biochemical processes of the cytoplasm (Hyman and Brangwynne 2011). Previous studies in C. elegans have shown that the thermodynamic effects of temperature on the cell cycle rate in nematodes follows an Arrhenius relationship and defines the thermal range where worms can be fertile. At the limits of this relationship a breakdown of the Arrhenius trend is observed (Begasse et al. 2015a). It was hypothesized that some type of discontinuous phase transition occurred in the embryonic cells of C. elegans (Begasse et al 2015). However, it remains unknown if there is the physiological link between a drop off in fertility and the embryonic breakdown of the Arrhenius trend. This work finds the link between a temperature driven phase separation of P granules and fertility. P granules are important for germ line development and the fertility of C. elegans (Kawasaki et al. 1998b). Here it is shown that P granules mix with the cytoplasm upon a temperature quench of 27ºC to T=18ºC and de-mix from the cytoplasm forming droplets upon a temperature downshift of temperature from 18ºC to 27ºC. P granules also show a reversible behavior mixing and de-mixing with changes in temperature in vivo, having a strong dependence of these liquid-like compartments with entropy. These results were further confirmed using a minimally reconstituted, in vitro P granule system and showed that PGL-3, a constitutive component of P granules, can phase separate and form liquid compartments in a similar way as happens in vivo. Additionally, here it is shown that P granule phase separation does not require the chemical activity of other cytoplasmic factors to drive the phase separation of compartments in vivo and in vitro, instead their formation is strongly driven to mix and de-mix with changes in temperature. Furthermore, a binary phase diagram was constructed in order to compare the response of P granules in vivo and in vitro, showing that P granules form and function as a temperature driven liquid phaseseparation. Altogether, this indicates that P granules in vivo and PGL-3 liquid-like compartments in vitro, share the same temperature of mixing and de-mixing which coincides with the fertile temperature range over which Caenorhabditis elegans can reproduce. This suggests that P granule phase separation could define the thermal range of the worm.:Table of Contents 1. Abstract 2. Introduction 2 . 1 . CYTOPLASMIC ORGANIZAT ION 2 . 2 . CYTOPLASMIC PHASE SEPARATIONS 2 . 3 . P GRANULES RESEMBLE L IQUID- L IKE PROPERTI ES 2 . 4 . PHASE CHANGES AND THE CELL CYCLE 3. Aim 4. Methods 4 . 1 . STRAINS 4 . 2 . TEMPERATURE CONTROL 4.2.1. HEATING/COOLING SETUP DEVELOPMENT AND MICROSCOPE STAGE 4.2.2. CONFOCAL SAMPLE HOLDER AND HEATING/COOLING DEVICE 4.2.3. SAMPLE PREPARATION 4.2.4. TEMPERATURE OF THE MICROSCOPE OBJECTIVE 4 . 3 . IN VI VO ASSAYS 4 . 4 . IN VI TRO ASSAY 5. Results 5 . 1 . TEMPERATURE AND P GRANULE PHASE SEPARATION 5 . 2 . P GRANULES ARE TEMPERATURE SENSITIVE COMPARTMENTS 5 . 3 . P GRANULES MIX WITH THE CYTOPLASM AT 27ºC 5 . 4 . P GRANULES DO NOT NEED THE INFLUENCE OF PPTR- 1 TO FORM DROPLETS 5 . 5 . P GRANULES REVERSIBLY MIX AND DE-MIX IN VIVO 5 . 6 . PGL- 3 GRANULES PHASE SEPARATE IN V ITRO AT PHYSIOLOGICAL CONDITIONS 5 . 7 . P GRANULE PHASE SEPARATION IS REVERSIBLE IN VI VO AND IN VI TRO 5 . 8 . AN IN V ITRO PHASE DIAGRAM TO COMPARE THE THERMAL L IMITS OF P GRANULES IN V IVO 6. Discussion 6 . 1 . P GRANULES MIX AND DE-MIX IN A REVERSIBLE MANNER 6 . 2 . CONCENTRATION AND THE SPATIAL CONTROL OF P GRANULES 6 . 3 . THE ROLE OF OTHER CHEMICAL REGULATORS 6 . 4 . ECOLOGICAL RELEVANCE OF P GRANULE PHASE SEPARATION 7. Concluding Remarks 8. Bibliograph

    Critical analysis of a Musculoskeletal Disorders Prevention Program

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    Critical analysis of a Musculoskeletal Disorders Prevention ProgramThe studies involving the development of occupational diseases and accidents at work prevention programs have delimited two facts. One of them is that the program must be linked to the general organization politics. The other fact is that the diagnosis and the intervention about the organizational culture are necessary for the program to reach its goals. This research have aimed to evaluate an ergonomic intervention called Legislature Court, – Prevention of Musculoskeletal Disorders Program – developed, during one year, at the in Santa Catarina, compounded by 61 work environments. The demand have come from the institution direction, which have noticed the growing rise of Musculoskeletal Disorders. Thus, the direction have hired two professionals from the Ergonomics area (phychologist and physiotherapist) for contributing to the team organization which would be formed by the institutions´employess. The PMDP have initially aimed: to investigate the diseases demand and to evaluate the professionals, able to participate in the multidisciplinary team which would develop the PMDP. The program have gathered diagnosis strategies and interventions highlighted by ergonomics, work psychology and physiotherapy. The strategies were brought in two dimensions: the organizational and the individual. On the individual dimension there were performed physical activities on the work environment, followed by discussions about body conscious, in 14 place of the institution, visitations for understanding the work conditions, followed by discussions about the furniture adequacy and body posture; and three groups of preventive activities. On the organizational dimension it was planned for the multidisciplinary team to integrate the department in charge of the maintenance of the building and the health department. For the critical analysis of the program’s results, the data were collected by: : a) historical rescue of the PMDP; b) surveys with the employees who partipated in the multidisciplinary team; c) questionnaires in a stratified pre-sample of the activities´particpants. The critical analysis of the program´s results, can be initially understood, by the political aspect, due to the fact that the multidisciplinary team was built aiming the self-management, facing the human relations´ institutionalization, which permeates the politics adopted by the Intitution. However, the team didn´t reflect about the politics ´attitude and how it was against the whole organization politics. The team professional project was intervening on the Musculoskeletal Disorders prevention. This made them to be recognized as references on Ergonomics and Health. However, the team wasn´t recognized by the institution’s direction, who didn’t have a commitment with the PMDP. To conclude, the result’s criticism shows the comprehension a team must have about its own politics, about its organization politics and how it can determine a Musculoskeletal Disorders Prevention Program and its limits

    Faculty Chamber Music Recital

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    Piano Trio No. 1 in D minor, Op. 49; Piano Trio No. 2 in C minor, Op. 66 / Felix Mendelssoh

    Decentralization, Happiness and the Perception of Institutions

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    This paper analyses whether the different powers and resources at the disposal of local and regional governments across Europe deliver greater satisfaction with political institutions and lead to greater personal happiness. The analysis uses microdata from the four available waves of the European social survey (2002, 2004, 2006 and 2008), including more than 160,000 observations of individuals living in 29 European countries. Our results reveal that political and fiscal decentralization have a positive and significant effect on individuals' overall happiness. Fiscal decentralization also exerts a significant effect on the level of satisfaction with political and economic institutions and with the education and health systems, whereas the effect of political decentralization on these variables is more limited. The results show that citizens seem to be happier with the actual capacity of their local governments to deliver than with the general principle that they can have a say on their daily politics and policies.satisfaction, Europe, happiness, well-being, fiscal and political decentralization
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