Kepler Presearch Data Conditioning I - Architecture and Algorithms for Error Correction in Kepler Light Curves

Kepler provides light curves of 156,000 stars with unprecedented precision. However, the raw data as they come from the spacecraft contain significant systematic and stochastic errors. These errors, which include discontinuities, systematic trends, and outliers, obscure the astrophysical signals in the light curves. To correct these errors is the task of the Presearch Data Conditioning (PDC) module of the Kepler data analysis pipeline. The original version of PDC in Kepler did not meet the extremely high performance requirements for the detection of miniscule planet transits or highly accurate analysis of stellar activity and rotation. One particular deficiency was that astrophysical features were often removed as a side-effect to removal of errors. In this paper we introduce the completely new and significantly improved version of PDC which was implemented in Kepler SOC 8.0. This new PDC version, which utilizes a Bayesian approach for removal of systematics, reliably corrects errors in the light curves while at the same time preserving planet transits and other astrophysically interesting signals. We describe the architecture and the algorithms of this new PDC module, show typical errors encountered in Kepler data, and illustrate the corrections using real light curve examples.Comment: Submitted to PASP. Also see companion paper "Kepler Presearch Data Conditioning II - A Bayesian Approach to Systematic Error Correction" by Jeff C. Smith et a

Vascular responses of the extremities to transdermal application of vasoactive agents in Caucasian and African descent individuals

This is an accepted manuscript of an article published by Springer in European Journal of Applied Physiology on 04/04/2015, available online: https://doi.org/10.1007/s00421-015-3164-2 The accepted version of the publication may differ from the final published version.© 2015, Springer-Verlag Berlin Heidelberg. Purpose: Individuals of African descent (AFD) are more susceptible to non-freezing cold injury than Caucasians (CAU) which may be due, in part, to differences in the control of skin blood flow. We investigated the skin blood flow responses to transdermal application of vasoactive agents. Methods: Twenty-four young males (12 CAU and 12 AFD) undertook three tests in which iontophoresis was used to apply acetylcholine (ACh 1 w/v %), sodium nitroprusside (SNP 0.01 w/v %) and noradrenaline (NA 0.5 mM) to the skin. The skin sites tested were: volar forearm, non-glabrous finger and toe, and glabrous finger (pad) and toe (pad). Results: In response to SNP on the forearm, AFD had less vasodilatation for a given current application than CAU (P = 0.027–0.004). ACh evoked less vasodilatation in AFD for a given application current in the non-glabrous finger and toe compared with CAU (P = 0.043–0.014) with a lower maximum vasodilatation in the non-glabrous finger (median [interquartile], AFD n = 11, 41[234] %, CAU n = 12, 351[451] %, P = 0.011) and non-glabrous toe (median [interquartile], AFD n = 9, 116[318] %, CAU n = 12, 484[720] %, P = 0.018). ACh and SNP did not elicit vasodilatation in the glabrous skin sites of either group. There were no ethnic differences in response to NA. Conclusion: AFD have an attenuated endothelium-dependent vasodilatation in non-glabrous sites of the fingers and toes compared with CAU. This may contribute to lower skin temperature following cold exposure and the increased risk of cold injuries experienced by AFD.Published versio

Identification of an epidermal keratinocyte AMPA glutamate receptor involved in dermatopathies associated with sensory abnormalities

Abstract. Introduction: Epidermal keratinocytes are increasingly recognized as active participants in the sensory transduction of itch and pain, processes known to involve primary afferent glutamatergic neurons. However, the role of keratinocyte glutamate signaling in sensory functioning is not fully understood. Here, we present the observation of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid–type glutamate receptors (AMPARs) in epidermal keratinocytes. Methods: Immunohistochemical and in situ hybridization analyses were conducted to assess the expression of AMPAR subunits in epidermal keratinocytes in mouse and human skin samples, and in organotypic cultures of human keratinocytes. In addition, reverse transcription PCR further confirmed the expression of GluA4-containing AMPAR in epidermal keratinocytes. Results: We found prominent immunolabeling for the GluA4 subunit of AMPAR in keratinocytes of glabrous and hairy skin of mouse epidermis, as well as in human epidermal keratinocytes. Reverse transcription PCR confirmed Gria4 transcript expression in epidermal mouse keratinocytes. In addition, expression of GRIA4 mRNA was confirmed in epidermal human keratinocytes by in situ hybridization. Immunohistochemical studies conducted in human skin biopsies from patients with atopic dermatitis and postherpetic neuralgia demonstrate that keratinocyte expression of GluA4 can be altered under pathological conditions. Moreover, a decrease of GluA4 expression was observed in organotypic cultures of human keratinocytes after direct application of algogenic agents. Conclusion: We provide evidence that GluA4-containing AMPARs are expressed in epidermal keratinocytes, that human pruritic and painful dermatopathologies have alterations in the keratinocyte expression levels of GluA4-containing AMPAR, and that itch- and pain-producing substances can directly regulate their production in keratinocytes

The diverse structures and functions of surfactant proteins

Surface tension at liquid–air interfaces is a major barrier that needs to be surmounted by a wide range of organisms; surfactant and interfacially active proteins have evolved for this purpose. Although these proteins are essential for a variety of biological processes, our understanding of how they elicit their function has been limited. However, with the recent determination of high-resolution 3D structures of several examples, we have gained insight into the distinct shapes and mechanisms that have evolved to confer interfacial activity. It is now a matter of harnessing this information, and these systems, for biotechnological purposes

Personal probabilities of probabilities

By definition, the subjective probability distribution of a random event is revealed by the (‘rational’) subject's choice between bets — a view expressed by F. Ramsey, B. De Finetti, L. J. Savage and traceable to E. Borel and, it can be argued, to T. Bayes. Since hypotheses are not observable events, no bet can be made, and paid off, on a hypothesis. The subjective probability distribution of hypotheses (or of a parameter, as in the current ‘Bayesian’ statistical literature) is therefore a figure of speech, an ‘as if’, justifiable in the limit. Given a long sequence of previous observations, the subjective posterior probabilities of events still to be observed are derived by using a mathematical expression that would approximate the subjective probability distribution of hypotheses, if these could be bet on. This position was taken by most, but not all, respondents to a ‘Round Robin’ initiated by J. Marschak after M. H. De-Groot's talk on Stopping Rules presented at the UCLA Interdisciplinary Colloquium on Mathematics in Behavioral Sciences. Other participants: K. Borch, H. Chernoif, R. Dorfman, W. Edwards, T. S. Ferguson, G. Graves, K. Miyasawa, P. Randolph, L. J. Savage, R. Schlaifer, R. L. Winkler. Attention is also drawn to K. Borch's article in this issue.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43847/1/11238_2004_Article_BF00169102.pd

Entrepreneurial Orientation Rhetoric in Franchise Organizations: The Impact of National Culture

This study examines the role of national culture on the entrepreneurial orientation (EO) rhetoric contained within franchisee recruitment promotional materials, where EO rhetoric is defined as the strategic use of words in organizational narratives to convey the risk taking, innovativeness, proactiveness, autonomy, and competitive aggressiveness of the firm. The sample comprised 378 franchise organizations, in five different countries (Australia, France, India, South Africa, and the UK). The results indicate that franchise systems operating in high uncertainty avoidance and feminine cultures use less entrepreneurially oriented rhetoric, suggesting that EO rhetoric in franchise organizations varies according to different national cultural contexts