2,321 research outputs found

    Proposed League Of Nations

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    Understanding The Effects Of Stellar Multiplicity On The Derived Planet Radii From Transit Surveys: Implications for Kepler, K2, and TESS

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    We present a study on the effect of undetected stellar companions on the derived planetary radii for the Kepler Objects of Interest (KOIs). The current production of the KOI list assumes that the each KOI is a single star. Not accounting for stellar multiplicity statistically biases the planets towards smaller radii. The bias towards smaller radii depends on the properties of the companion stars and whether the planets orbit the primary or the companion stars. Defining a planetary radius correction factor XRX_R, we find that if the KOIs are assumed to be single, then, {\it on average}, the planetary radii may be underestimated by a factor of āŸØXRāŸ©ā‰ˆ1.5\langle X_R \rangle \approx 1.5. If typical radial velocity and high resolution imaging observations are performed and no companions are detected, this factor reduces to āŸØXRāŸ©ā‰ˆ1.2\langle X_R \rangle \approx 1.2. The correction factor āŸØXRāŸ©\langle X_R \rangle is dependent upon the primary star properties and ranges from āŸØXRāŸ©ā‰ˆ1.6\langle X_R \rangle \approx 1.6 for A and F stars to āŸØXRāŸ©ā‰ˆ1.2\langle X_R \rangle \approx 1.2 for K and M stars. For missions like K2 and TESS where the stars may be closer than the stars in the Kepler target sample, observational vetting (primary imaging) reduces the radius correction factor to āŸØXRāŸ©ā‰ˆ1.1\langle X_R \rangle \approx 1.1. Finally, we show that if the stellar multiplicity rates are not accounted for correctly, occurrence rate calculations for Earth-sized planets may overestimate the frequency of small planets by as much as 15āˆ’2015-20\%.Comment: 10 pages, 6 Figures, Accepted for publication in The Astrophysical Journal (Fix typo in Equation 6 of original astroph submission; correction also submitted to Journal

    The role of fretting corrosion and fretting fatigue in aircraft rivet hole cracking

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    Personnel in the Quality and Integrity Design Engineering Center (QIDEC) at the University of Utah are working under a two year grant from the FAA to better understand the role of fretting corrosion and fretting fatigue in aircraft rivet hole cracking. The current program follows a one year grant program which was completed in 1993. This paper provides a status report on the results of these grant programs. Recent effort has been focused on developing basic fretting fatigue models which consider variation in the coefficient of friction with time and location within the fretting interface. This is a very important characteristic of the QIDEC model because coefficient of friction varies significantly during the fretting fatigue process. Copies of QIDEC documents discussed in this paper can be obtained by contacting the authors

    The Birmingham Boron Neutron Capture Therapy (BNCT) project : developments towards selective internal particle therapy

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    This paper will review progress on two aspects of the Birmingham BNCT project. Firstly on evaluation of the effects of high and low LET radiations when delivered simultaneously, and secondly on attempts to optimise delivery of the boron carrier compound BPA through pharmacokinetic studies. Simultaneous or non-simultaneous irradiations of V79 cells with alpha-particle and X-ray irradiations were performed. Alpha doses of 2 and 2.5 Gy were chosen and the impact on survival when delivered separately or simultaneously with variable doses of X-rays was evaluated. The pharmacokinetics of the delivery of a new formulation of BPA (BPA-mannitol) are being investigated in brain tumour patients through a study with 2 Ɨ 2 design featuring intravenous and intracarotid artery infusion of BPA, with or without a mannitol bolus. On the combined effect of low and high LET radiations, a synergistic effect was observed when alpha and X-ray doses are delivered simultaneously. The effect is only present at the 2.5 Gy alpha dose and is a very substantial effect on both the shape of the survival curve and the level of cell killing. This indicates that the alpha component may have the effect of inhibiting the repair of damage from the low LET radiation dose delivered simultaneously. On the pharmacokinetics of BPA, data on the first three cohorts indicate that bioavailability of BPA in brain ECF is increased substantially through the addition of a mannitol bolus, as well as by the use of intracarotid artery route of infusion. In both cases, for some patients the levels after infusion approach those seen in blood, whereas the ECF levels for intravenous infusion without mannitol are typically less than 10% of the blood values

    To what extent is behaviour a problem in English schools?:Exploring the scale and prevalence of deficits in classroom climate

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    The working atmosphere in the classroom is an important variable in the process of education in schools, with several studies suggesting that classroom climate is an important influence on pupil attainment. There are wide differences in the extent to which classroom climate is considered to be a problem in English schools. Some ā€˜officialā€™ reports suggest that behaviour in schools is ā€˜satisfactory or betterā€™ in the vast majority of schools; other sources have pointed to behaviour being a serious and widespread problem. The paper details four studies conducted over the past decade which aimed to explore these disparities. The aim of the research was to gain a more accurate insight into the extent to which deficits in classroom climate limit educational attainment and equality of educational opportunity in English schools. The findings question the suggestion that behaviour is satisfactory or better in 99.7% of English schools and the concluding section suggests ways in which deficits in classroom climate might be addressed. Although the study is limited to classrooms in England, OECD studies suggest that deficits in the working atmosphere in classrooms occur in many countries. The study therefore has potential relevance for education systems in other countries

    Maternal neurofascin-specific autoantibodies bind to structures of the fetal nervous system during pregnancy, but have no long term effect on development in the rat

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    Neurofascin was recently reported as a target for axopathic autoantibodies in patients with multiple sclerosis (MS), a response that will exacerbate axonal pathology and disease severity in an animal model of multiple sclerosis. As transplacental transfer of maternal autoantibodies can permanently damage the developing nervous system we investigated whether intrauterine exposure to this neurofascin-specific response had any detrimental effect on white matter tract development. To address this question we intravenously injected pregnant rats with either a pathogenic anti-neurofascin monoclonal antibody or an appropriate isotype control on days 15 and 18 of pregnancy, respectively, to mimic the physiological concentration of maternal antibodies in the circulation of the fetus towards the end of pregnancy. Pups were monitored daily with respect to litter size, birth weight, growth and motor development. Histological studies were performed on E20 embryos and pups sacrificed on days 2, 10, 21, 32 and 45 days post partum. Results: Immunohistochemistry for light and confocal microscopy confirmed passively transferred anti-neurofascin antibody had crossed the placenta to bind to distinct structures in the developing cortex and cerebellum. However, this did not result in any significant differences in litter size, birth weight, or general physical development between litters from control mothers or those treated with the neurofascin-specific antibody. Histological analysis also failed to identify any neuronal or white matter tract abnormalities induced by the neurofascin-specific antibody. Conclusions: We show that transplacental transfer of circulating anti-neurofascin antibodies can occur and targets specific structures in the CNS of the developing fetus. However, this did not result in any pre- or post-natal abnormalities in the offspring of the treated mothers. These results assure that even if anti-neurofascin responses are detected in pregnant women with multiple sclerosis these are unlikely to have a negative effect on their children

    Reaction time variability in children with ADHD symptoms and/or dyslexia.

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    Reaction time (RT) variability on a Stop Signal task was examined among children with attention deficit hyperactivity disorder (ADHD) symptoms and/or dyslexia in comparison to typically developing (TD) controls. Children's go-trial RTs were analyzed using a novel ex-Gaussian method. Children with ADHD symptoms had increased variability in the fast but not the slow portions of their RT distributions compared to those without ADHD symptoms. The RT distributions of children with dyslexia were similar to those of TD-controls. It is argued that variability in responding may be underpinned by impairments in response preparation or timing during Stop Signal tasks

    Strategic Planning for Environmental Stewardship at Eastern Kentucky University

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    The 2006-2010 Strategic Plan for Eastern Kentucky University, under Strategic Direction 5.4, mandates the formulation of a plan to guide the University toward greater environmental stewardship. The creation and implementation of that plan is the charge of the Eastern Committee on Responsible Environmental Stewardship (ECRES), which was formed in September of 2005. On October 27th, 2006, ECRES hosted a Strategic Planning Workshop. This workshop brought together a wide range of paticipants, including elected officials, college and university representatives, and interested citizens. The result was a broad consensus in the identification of environmental goals and objectives toward which EKU should strive

    White Habits, Antiā€Racism, and Philosophy as a Way of Life

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    This paper examines Pierre Hadotā€™s philosophy as a way of life in the context of race. I argue that a ā€œway of lifeā€ approach to philosophy renders intelligible how anti-racist confrontation of racist ideas and institutionalized white complicity is a properly philosophical way of life requiring regulated reflection on habits ā€“ particularly, habits of whiteness. I first rehearse some of Hadotā€™s analysis of the ā€œway of lifeā€ orientation in philosophy, in which philosophical wisdom is understood as cultivated by actions which result in the creation of wise habits. I analyze a phenomenological claim about the nature of habit implied by the ā€œway of lifeā€ approach, namely, that habits can be both the cause and the effect of action. This point is central to the ā€œway of lifeā€ philosophy, I claim, in that it makes possible the intelligent redirection of habits, in which wise habits are more the effect than simply the cause of action. Lastly, I illustrate the ā€œway of lifeā€ approach in the context of anti-racism by turning to Linda MartĆ­n Alcoffā€™s whiteness anti-eliminativism, which outlines a morally defensible transformation of the habits of whiteness. I argue that anti-racism provides an intelligible context for modern day forms of what Hadot calls ā€œspiritual exercisesā€ insofar as the ā€œway of lifeā€ philosophy is embodied in the practice of whites seeing themselves seeing as white and seeing themselves being seen as white

    Parameter identification problems in the modelling of cell motility

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    We present a novel parameter identification algorithm for the estimation of parameters in models of cell motility using imaging data of migrating cells. Two alternative formulations of the objective functional that measures the difference between the computed and observed data are proposed and the parameter identification problem is formulated as a minimisation problem of nonlinear least squares type. A Levenbergā€“Marquardt based optimisation method is applied to the solution of the minimisation problem and the details of the implementation are discussed. A number of numerical experiments are presented which illustrate the robustness of the algorithm to parameter identification in the presence of large deformations and noisy data and parameter identification in three dimensional models of cell motility. An application to experimental data is also presented in which we seek to identify parameters in a model for the monopolar growth of fission yeast cells using experimental imaging data. Our numerical tests allow us to compare the method with the two different formulations of the objective functional and we conclude that the results with both objective functionals seem to agree
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