Nonparametric Reconstruction of the Dark Energy Equation of State

A basic aim of ongoing and upcoming cosmological surveys is to unravel the mystery of dark energy. In the absence of a compelling theory to test, a natural approach is to better characterize the properties of dark energy in search of clues that can lead to a more fundamental understanding. One way to view this characterization is the improved determination of the redshift-dependence of the dark energy equation of state parameter, w(z). To do this requires a robust and bias-free method for reconstructing w(z) from data that does not rely on restrictive expansion schemes or assumed functional forms for w(z). We present a new nonparametric reconstruction method that solves for w(z) as a statistical inverse problem, based on a Gaussian Process representation. This method reliably captures nontrivial behavior of w(z) and provides controlled error bounds. We demonstrate the power of the method on different sets of simulated supernova data; the approach can be easily extended to include diverse cosmological probes.Comment: 16 pages, 11 figures, accepted for publication in Physical Review

Genome-Wide Screen of Genes Required for Caffeine Tolerance in Fission Yeast

Isabel A. Calvo et al...Background An excess of caffeine is cytotoxic to all eukaryotic cell types. We aim to study how cells become tolerant to a toxic dose of this drug, and the relationship between caffeine and oxidative stress pathways. Methodology/Principal Findings We searched for Schizosaccharomyces pombe mutants with inhibited growth on caffeine-containing plates. We screened a collection of 2,700 haploid mutant cells, of which 98 were sensitive to caffeine. The genes mutated in these sensitive clones were involved in a number of cellular roles including the H2O2-induced Pap1 and Sty1 stress pathways, the integrity and calcineurin pathways, cell morphology and chromatin remodeling. We have investigated the role of the oxidative stress pathways in sensing and promoting survival to caffeine. The Pap1 and the Sty1 pathways are both required for normal tolerance to caffeine, but only the Sty1 pathway is activated by the drug. Cells lacking Pap1 are sensitive to caffeine due to the decreased expression of the efflux pump Hba2. Indeed, ?hba2 cells are sensitive to caffeine, and constitutive activation of the Pap1 pathway enhances resistance to caffeine in an Hba2-dependent manner. Conclusions/Significance With our caffeine-sensitive, genome-wide screen of an S. pombe deletion collection, we have demonstrated the importance of some oxidative stress pathway components on wild-type tolerance to the drug.This work was supported by Direccion General de Investigacion of Spain Grant BFU2006-02610, and by the Spanish program Consolider-Ingenio 2010 Grant CSD 2007-0020, to E.H.Peer reviewe

Beyond equilibrium climate sensitivity

ISSN:1752-0908ISSN:1752-089

Estimation of cointegrating vectors with time series measured at diferent periodicity

[eng] We discuss the effects of temporal aggregation on the estimation of cointegrating vectors and on testing linear restrictions on this vector. We adopt a discrete time approach and demonstrate, in contrast with the findings of Chambers (2003, Econometric Theory 19, 49-77), who adopts a continuous time approach, that in some situations, when the regressand must be aggregated, systematic sampling is preferable to average sampling for estimation purposes. Like Chambers, we show that the best aggregation scheme for regressors, in terms of asymptotic estimation efficiency, is always average sampling. We also show that different types of aggregation have no influence on the relative size of tests of linear restrictions on the cointegration vector.We thank Soren Johansen, Niels Haldrup, Raquel Waters, the associate editor, and two anonymous referees for their helpful comments. Of course, any remaining error is the responsibility of the authors. The first author gratefully acknowledges the financial support of a Marie Curie Fellowship of the European Community Programme "Improving the Human Research Potential and the Socio-Economic Knowledge Base" under contract HPMF-CT-2002-01662 and the Danish Research Council. The second author gratefully acknowledges the financial support of the Spanish Ministry of Science and Technology SEC2002-01512

Common Periodic Correlation Features and the Interaction of Stocks and Flows in Daily Airport Data

[eng] We propose the multivariate representation of univariate and bivariate (possibly nonstationary) periodic models as a benchmark for the imposition of common periodic correlation (CPC) feature restrictions to obtain parameter parsimony. CPCs are short-run common dynamic features that co-vary across the different days of the week and possibly also across weeks and that can be common across different time series. We also show how periodic models can be used to describe interesting dynamic links in the interaction between stock and flow variables. We apply the proposed modeling framework to a dataset of daily arrivals and departures in airport transit data

Palliative Care Professionals' Inner Life: Exploring the Mediating Role of Self-Compassion in the Prediction of Compassion Satisfaction, Compassion Fatigue, Burnout and Wellbeing.

Palliative care professionals are exposed to suffering on a daily basis. Working in such an environment frequently raises existential issues, psychological challenges, and emotional distress, that can detract from compassionate care. Identifying factors that help professionals cope with frequent exposure to issues related to mortality, such as compassion, could enhance palliative care providers' and patients' quality of life and wellbeing. To improve our understanding of the factors associated with professionals' inner life studying the role of self-compassion as a mediating variable between self-care and awareness and professionals' quality of life, and quantifying the impact of compassionate care. A cross-sectional online survey of palliative care professionals was conducted through the Spanish Society of Palliative Care. 296 professionals answered the survey. The model tested showed an adequate fit (χ <sup>2</sup> (212) = 476.688 (P < .001), CFI = .907, RMSEA = .066 [.058,.073], and SRMR = .068), and the hypotheses were supported. Self-care and awareness predicted coping with death and self-compassion, which in turn predicted professional quality of life. Self-compassion had the greatest predictive power. Professional quality of life showed a statistically significant and positive effect on personal wellbeing, explaining more than 50% of its variance (R <sup>2</sup> = .574; P < .001). For palliative care professionals, the cultivation of self-compassion is equally needed as compassion for others. Professional quality of life and compassionate care are related to professionals' wellbeing: when professionals take care of themselves, this will lead in a more compassionate care, but also in healthier, happier professionals