620 research outputs found

    Isocurvature fluctuations in the effective Newton's constant

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    We present a new isocurvature mode present in scalar-tensor theories of gravity that corresponds to a regular growing solution in which the energy of the relativistic degrees of freedom and the scalar field that regulates the gravitational strength compensate during the radiation dominated epoch on scales much larger than the Hubble radius. We study this isocurvature mode and its impact on anisotropies of the cosmic microwave background for the simplest scalar-tensor theory, i.e. the extended Jordan-Brans-Dicke gravity, in which the scalar field also drives the acceleration of the Universe. We use Planck data to constrain the amplitude of this isocurvature mode in the case of fixed correlation with the adiabatic mode and we show how this mode could be generated in a simple two field inflation model.Comment: Version updated to match published version. No changes in the result

    A measurement method of routing flexibility in manufacturing systems

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    Article history: Received 27 January 2011 Received in revised form 25 February 2011 Accepted 2 March 2011 Available online 3 March 2011 This paper focuses on routing flexibility, which is the ability to manufacture a part type via several routes and/or to perform different operations on more than one machine. Specifically, the paper presents a comprehensive method for the measurement of routing flexibility, in a generic manufacturing system. The problem is approached in a modular way, starting from a basic set of flexibility indexes. These are progressively extended to include more comprehensive and complex routing attributes, such as: the average efficiency, the range and the homogeneous distribution of the alternative routes. Two procedures are finally proposed to compare manufacturing systems in terms of routing flexibility. The first one uses a vectorial representation of the previously defined indexes and the second one is based on data envelopment analysis, a multi-criteria decision making approach. The paper concludes with a numerical example, supported by discrete event simulation, which validates the proposed approach. © 2011 Growing Science Ltd. All rights reserve

    Quantitative real time PCR approach to study gene expression profile during prenatal growth of skeletal muscle in pig of Duroc and Pietrain breeds

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    The quantitative real time-PCR (QRT-PCR) is a very sensitive method used to quantify mRNA level in gene expression analysis. Combining amplification, detection and quantification in a single step, allows a more accurate measurement compared to the traditional PCR end point analysis (Pfaffl, 2001; Bustin, 2002)

    M/M/1 queuing model with ordinary maintenance and breakdowns

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    An M/M/1 system with ordinary maintenance and possibility of breakdowns is considered from a practical point of view. An appropriate equation for the probability of n units in the system at any instant of time is written in terms of the Green function of the conventional M/M/1 model and solved by an iterative technique which imposes a periodic regime state. Some Monte Carlo simulations are used to assess the accuracy of the iterative process, i. e. verify that it really converges to the correct solution. Special attention is turned to the analysis of the error that is introduced if the different breakdowns that may occur during the service interval are replaced by a single cumulative waste of time. Numerical results are reported for the special cases in which this cumulative breakdown in placed at the beginning or at the end of the service interval. or is uniformly distributed. To some extent, part of the analysis is deliberately approximated, even if good accuracy is always preserved. The extension to the M/G/1 model is also considered

    High brightness 100 W-50 μm delivery blue laser diode module

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    Blue laser diodes are emerging as the next revolution in laser material processing, especially for high reflective materials, such as copper and gold. The paper presents the most recent evolution of a family of medium-high power and high brightness devices specifically conceived for micro-machining applications. The modules make use of a proprietary architecture based on the combination of commercial laser diodes in TO9 package. The diodes are first organized in rows staggered along the fast axis, then the rows are multiplexed along the fast axis; finally, wavelength and polarization multiplexing are exploited to achieve up to 100W of power into a 50 μm/0.22NA fiber

    Online Motion Planning for Safe Human–Robot Cooperation Using B-Splines and Hidden Markov Models

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    When humans and robots work together, ensuring safe cooperation must be a priority. This research aims to develop a novel real-time planning algorithm that can handle unpredictable human movements by both slowing down task execution and modifying the robot’s path based on the proximity of the human operator. To achieve this, an efficient method for updating the robot’s motion is developed using a two-fold control approach that combines B-splines and hidden Markov models. This allows the algorithm to adapt to a changing environment and avoid collisions. The proposed framework is thus validated using the Franka Emika Panda robot in a simple start–goal task. Our algorithm successfully avoids collision with the moving hand of an operator monitored by a fixed camera

    Deregulated PTEN/PI3K/AKT/mTOR signaling in prostate cancer: Still a potential druggable target?

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    Although the prognosis of patients with localized prostate cancer is good after surgery, with a favorable response to androgen deprivation therapy, about one third of them invariably relapse, and progress to castration-resistant prostate cancer. Overall, prostate cancer therapies remain scarcely effective, thus it is mandatory to devise alternative treatments enhancing the efficacy of surgical castration and hormone administration. Dysregulation of the phosphoinositide 3-kinase pathway has attracted growing attention in prostate cancer due to the highly frequent association of epigenetic and post-translational modifications as well as to genetic alterations of both phosphoinositide 3-kinase and PTEN to onset and/or progression of this malignancy, and to resistance to canonical androgen-deprivation therapy. Here we provide a summary of the biological functions of the major players of this cascade and their deregulation in prostate cancer, summarizing the results of preclinical and clinical studies with PI3K signaling inhibitors and the reasons of failure independent from genomic changes

    Identification of SNPs in the promoter of \u3b2-lactoglobulin gene in three Sicilian goat breeds

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    The aim of this work was to sequence the full-length promoter region of the caprine \u3b2-lactoglobulin (\u3b2-lg) gene in three Sicilian goat breeds (Girgentana, Maltese, and Derivata di Siria), in order to identify polymorphisms, to search for transcription factors (TFs) sites, and to check if polymorphisms found lay within TFs binding sites. The promoter region of \u3b2-lg gene in Sicilian goat breeds showed high level of polymorphism due to the presence of 31 SNPs. Binding sites for several TFs were found within the goat \u3b2-lg promoter and within regions conserved between ovine and caprine species. Two SNPs were detected within TFs binding sites, such as MPBF and NF-I. Further studies are in progress to confirm polymorphic sites, to evaluate the possible effect of these mutations on binding affinity of TFs, their relationship with \u3b2-lg gene expression, and the functional role of SNPs within the TFs sites of the promoter region on milk trait

    Polymorphisms of beta-lactoglobulin promoter region in three Sicilian goat breeds

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    Several beta-lactoglobulin (BLG) polymorphisms have been described within the proximal promoter region and coding region of the caprine gene, although no genetic variants affecting the protein amino acid composition and/or expression level have been characterized so far. Binding sites for several transcription factors (TFs) are present in the BLG promoter region. The aims of this work were to sequence the full-length promoter region of three Sicilian goat breeds in order to identify polymorphisms, analyze the identified haplotypes, search for differences between breeds for the presence of polymorphisms in this gene region, search for putative TFs binding sites, and check if polymorphisms lay within the identified TFs binding sites. The promoter region of BLG gene in Sicilian goat breeds showed high level of polymorphism due to the presence of 36 single nucleotide polymorphisms (SNPs). Association between polymorphic sites was computed within the whole sample analyzed and 18 haplotypes were inferred. Binding sites for three milk protein binding factors (MPBFs) and four nuclear factor-I (NF-I) were found within BLG promoter region based on the ovine sequence. The identification of some SNPs within TFs binding sites allowed hypothesizing the loss of TFs. Further studies are in progress to evaluate the effect of these mutations on binding affinity of TFs, the functional interaction of the TFs with the goat BLG promoter, and the relationship of the polymorphisms with BLG gene expression and milk production and composition
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