43,614 research outputs found

    CNV and nervous system diseases - what's new?

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    Several new genomic disorders caused by copy number variation (CNV) of genes whose dosage is critical for the physiological function of the nervous system have been recently identified. Dup(7)(q11.23) patients carry duplications of the genomic region deleted in Williams-Beuren syndrome, they are characterized by prominent speech delay. The phenotypes of Potocki-Lupski syndrome and MECP2 duplication syndrome were neuropsychologically examined in detail, which revealed autism as an endophenotype and a prominent behavioral feature of these disorders. Tandem duplication of LMNB1 was reported to cause adult-onset autosomal dominant leukodystrophy. PAFAH1B1/LIS1 and YWHAE, which were deleted in isolated lissencephaly (PAFAH1B1/LIS1 alone) and Miller-Dieker syndrome (both genes), were found to be duplicated in patients with developmental delay. Finally, two novel microdeletion syndromes affecting 17q21.31 and 15q13.3, as well as their reciprocal duplications, were also identified. In this review, we provide an overview of the phenotypic manifestation of these syndromes and the rearrangements causing them. Copyright (C) 2009 S. Karger AG, Base

    Smooth Multirate Multicast Congestion Control

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    A significant impediment to deployment of multicast services is the daunting technical complexity of developing, testing and validating congestion control protocols fit for wide-area deployment. Protocols such as pgmcc and TFMCC have recently made considerable progress on the single rate case, i.e. where one dynamic reception rate is maintained for all receivers in the session. However, these protocols have limited applicability, since scaling to session sizes beyond tens of participants necessitates the use of multiple rate protocols. Unfortunately, while existing multiple rate protocols exhibit better scalability, they are both less mature than single rate protocols and suffer from high complexity. We propose a new approach to multiple rate congestion control that leverages proven single rate congestion control methods by orchestrating an ensemble of independently controlled single rate sessions. We describe SMCC, a new multiple rate equation-based congestion control algorithm for layered multicast sessions that employs TFMCC as the primary underlying control mechanism for each layer. SMCC combines the benefits of TFMCC (smooth rate control, equation-based TCP friendliness) with the scalability and flexibility of multiple rates to provide a sound multiple rate multicast congestion control policy.National Science Foundation (ANI-9986397, ANI-0092196

    Chinese Overseas M&A Performance and the go Global Policy

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    This paper investigates whether stock markets view Chinese OMAs as increasing shareholder wealth. The subject is of interest given the influential role that the government plays in Chinese firms’ overseas activities, and the fact that the government may have objectives other than maximization of shareholder wealth. We examine 145 OMAs by Chinese acquiring firms over the year 1994-2008. We find some evidence that markets positively responded to news of Chinese OMAs. However, we also find that markets responded less favorably after China implemented its Go Global policy encouraging overseas investment. We hypothesize two reasons for this: First, the expansion of OMAs under Go Global resulted in Chinese firms pursuing less attractive targets, on average. Second, Go Global re-directed investment towards industries having national strategic value but diminished profit value. Using a Blinder-Oaxaca decomposition procedure, we find no evidence to support this latter hypothesis. Thus, to whatever extent strategic interests may motivate China’s Go Global policy, it does not appear that their pursuit has come at the expense of shareholder wealth.Economic Development; China Economy; Overseas Mergers and Acquisitions; Event Study; Go Global

    One For All or All For One? Using Multiple-listing Information in Event Studies

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    In an event study where at least some of the sample firms have their equity securities listed in more than one market, the question arises as to which is the most appropriate market (or markets) to use for the purpose of estimating mean abnormal returns. When arbitrage activity across these markets is restricted in some way, estimating abnormal returns from just one of the markets potentially throws away valuable information. On the other hand, indiscriminate pooling is likely to result in the same information being counted more than once. We develop a Generalized Least Squares estimator that (i) uses all the information available from multiple listings, (ii) ‘downweights’ listing observations that provide little new information, and (iii) yields efficient abnormal return estimates. Finally, we apply this generalized approach to a sample of Chinese foreign mergers and acquisitions and compare the results with conventional estimates of mean abnormal returns.event study; multiple listings; mergers and acquisitions; China

    Optimization Techniques for the Power Beaming Analysis of Microwave Transmissions from a Space-Based Solar Power Satellite

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    In the 21st century, the development of technologies to produce carbon free power sources remains paramount. In this paper, we study an optimal power transmission strategy from a space-based satellite generation station to Earth using scalar diffraction theory. The resulting model is then solved via a spectral method that guarantees a compactly supposed profile from the transmitting antenna. Finally, the problem is then solved via a more general pseudo-spectral method using control theory

    Make It Simple and Light: Some Thoughts on Real Estate Related Taxation in China

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    This article discusses the advantages and disadvantages of real estate-related taxes that might be imposed in mainland China, in light of the government’s needs for tax revenue and the economy’s need for incentives to develop land. Some policy recommendations are presented, based on an analysis of real estate taxation in general and of China’s specific needs. As one recent article has noted, understanding how behavior adjusts in response to taxation is one of the most important issues in public finance.1China, Public Finance, Real Estate Taxation

    LU factorization with panel rank revealing pivoting and its communication avoiding version

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    We present the LU decomposition with panel rank revealing pivoting (LU_PRRP), an LU factorization algorithm based on strong rank revealing QR panel factorization. LU_PRRP is more stable than Gaussian elimination with partial pivoting (GEPP). Our extensive numerical experiments show that the new factorization scheme is as numerically stable as GEPP in practice, but it is more resistant to pathological cases and easily solves the Wilkinson matrix and the Foster matrix. We also present CALU_PRRP, a communication avoiding version of LU_PRRP that minimizes communication. CALU_PRRP is based on tournament pivoting, with the selection of the pivots at each step of the tournament being performed via strong rank revealing QR factorization. CALU_PRRP is more stable than CALU, the communication avoiding version of GEPP. CALU_PRRP is also more stable in practice and is resistant to pathological cases on which GEPP and CALU fail.Comment: No. RR-7867 (2012

    Stochastic stability of viscoelastic systems under Gaussian and Poisson white noise excitations

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    As the use of viscoelastic materials becomes increasingly popular, stability of viscoelastic structures under random loads becomes increasingly important. This paper aims at studying the asymptotic stability of viscoelastic systems under Gaussian and Poisson white noise excitations with Lyapunov functions. The viscoelastic force is approximated as equivalent stiffness and damping terms. A stochastic differential equation is set up to represent randomly excited viscoelastic systems, from which a Lyapunov function is determined by intuition. The time derivative of this Lyapunov function is then obtained by stochastic averaging. Approximate conditions are derived for asymptotic Lyapunov stability with probability one of the viscoelastic system. Validity and utility of this approach are illustrated by a Duffing-type oscillator possessing viscoelastic forces, and the influence of different parameters on the stability region is delineated
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