611 research outputs found

    Threading holder based on axial metal cylinder pins to reduce tap risk during reversion instant

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    Internal thread profiles are used widely in manufacturing processes with the aim of assembling/disassembling different components during maintenance activities from the aeronautics sector until common industrial parts. The threading process is one of the last operations carried out to obtain those components, and consequently, it is an operation of high added value. Threading is a complex operation that must carefully synchronize the rotation with the feed movements to avoid tool breakage during the instant of tapping reversion stage. In order to avoid this risk, several toolholders were developed present in the literature but deficiencies in terms of stability and productivity. Therefore, in this work, a new toolholder is proposed in which the common springs used to mitigate the lack of perfect synchronization between rotation and feed movements are replaced by elastic metal pins achieving a torsional compliance toolholder. The results show that the use of the proposed toolholder implies not only a productivity increase but also a surface integrity improvement as well as a stress reduction that the cutting tap is subjected and thus, achieving a substantial improvement in the current tapping processes. In particular, the use of the proposed toolholder implied a 75% reduction of the maximum stress achieved in the reversal instant, improving 20% tool life with an increase of 30% cutting speed. Therefore, the use of the proposed toolholder implies a substantial improvement in the current tapping processes

    Effects of laser-textured on rake face in turning PCD tools for Ti6Al4V

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    The demand inherent to the aeronautical industry in terms of productivity and quality requirements leads to develop new cutting tools. Hence, PCD tools meet the requirements in productivity while machining low machinability aeronautical alloys such as Ti6Al4V. Tool chipbreakers play a considerable role in terms of tool life. However, due to the extreme conditions (temperature and pressure) required to manufacture PCD tools, any complex geometry on tool rake faces is not viable, so chipbreakers are not possible, except for those external to inserts. This work proposes a groove-type laser engraved chipbreaker design and a manufacturing methodology, with experimental validation on turning a Ti6Al4V workpiece. The so-manufactured chipbreakers achieve titanium alloy chip fragmentation, making easy chip removal from the cutting zone. A set of experiments involving various laser parameters to characterize the PCD depth and surface integrity and experimental validation for those chipbreakers designs were carried out in finishing cutting conditions. The optimum parameters for the engraving of PCD were found, obtaining satisfactory breakage of titanium chips. Chip length was always below 17.29 mm.Authors are grateful to Basque government group IT IT1337- 19, the Ministry of Mineco REF DPI2016-74845-R and PID2019- 109340RB-I00, and the UPV/EHU itself for the financial aid for the pre-doctoral grants PIF 19/96

    Evolution of genetic networks for human creativity

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    The genetic basis for the emergence of creativity in modern humans remains a mystery despite sequencing the genomes of chimpanzees and Neanderthals, our closest hominid relatives. Data-driven methods allowed us to uncover networks of genes distinguishing the three major systems of modern human personality and adaptability: emotional reactivity, self-control, and self-awareness. Now we have identified which of these genes are present in chimpanzees and Neanderthals. We replicated our findings in separate analyses of three high-coverage genomes of Neanderthals. We found that Neanderthals had nearly the same genes for emotional reactivity as chimpanzees, and they were intermediate between modern humans and chimpanzees in their numbers of genes for both self-control and self-awareness. 95% of the 267 genes we found only in modern humans were not protein-coding, including many long-non-coding RNAs in the self-awareness network. These genes may have arisen by positive selection for the characteristics of human well-being and behavioral modernity, including creativity, prosocial behavior, and healthy longevity. The genes that cluster in association with those found only in modern humans are over-expressed in brain regions involved in human self-awareness and creativity, including late-myelinating and phylogenetically recent regions of neocortex for autobiographical memory in frontal, parietal, and temporal regions, as well as related components of cortico-thalamo-ponto-cerebellar-cortical and cortico-striato-cortical loops. We conclude that modern humans have more than 200 unique non-protein-coding genes regulating co-expression of many more protein-coding genes in coordinated networks that underlie their capacities for self-awareness, creativity, prosocial behavior, and healthy longevity, which are not found in chimpanzees or Neanderthals.Peer reviewe

    Diagnosis features of pediatric Gaucher disease patients in the era of enzymatic therapy, a national-base study from the Spanish Registry of Gaucher Disease

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    Background: The enzymatic replacement therapy (ERT) availability for Gaucher disease (GD) has changed the landscape of the disease, several countries have screening programs. These actions have promoted the early diagnosis and avoided many complications in pediatric patients. In Spain ERT has been available since 1993 and 386 patients have been included in the Spanish Registry of Gaucher Disease (SpRGD). The aim of this study is to analyze the impact of ERT on the characteristics at time of diagnosis and initial complications in pediatric Gaucher disease patients. Aim: To analyze the impact of ERT on the characteristics at time of diagnosis and initial complications in pediatric Gaucher disease patients. Methods: A review of data in SpRGD from patients'' diagnosed before 18 years old was performed. The cohort was split according the year of diagnosis (=1994, cohort A; =1995, cohort B). Results: A total of 98 pediatric patients were included, GD1: 80, GD3: 18; mean age: 7.2 (0.17-16.5) years, 58 (59.2%) males and 40 (40.8%) females. Forty-five were diagnosed = 1994 and 53 = 1995. Genotype: N370S/N370S: 2 (2.0%), N370S/L444P: 27 (27.5%), N370S/other: 47 (48%), L444P/L444P: 7 (7.1%), L444P/D409H: 2 (2.0%), L444P/other: 3 (6.2%), other/other: 10 (10.2%). The mean age at diagnosis was earlier in patients diagnosed after 1995 (p < 0.001) and different between the subtypes, GD1: 8.2 (0.2-16.5) years and GD3: 2.8 (0.17-10.2) years (p < 0.001). There were more severe patients in the group diagnosed before 1994 (p = 0.045) carrying L444P (2), D409H (2), G377S (1), G195W (1) or the recombinant mutation. The patients'' diagnosed =1994 showed worse cytopenias, higher chance of bone vascular complications at diagnosis and previous spleen removal. The patients started ERT at a median time after diagnosis of 5.2 years [cohort A] and 1.6 years [cohort B] (p < 0.001). Conclusions: The early diagnosis of Gaucher disease in the era of ERT availability has permitted to reduce the incidence of severe and irreversible initial complication in pediatric patients, and this has permitted better development of these patients. This is the largest pediatric cohort from a national registry

    Advances in infrastructures and tools for multiagent systems

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    In the last few years, information system technologies have focused on solving challenges in order to develop distributed applications. Distributed systems can be viewed as collections of service-provider and ser vice-consumer components interlinked by dynamically defined workflows (Luck and McBurney 2008).Alberola Oltra, JM.; Botti Navarro, VJ.; Such Aparicio, JM. (2014). Advances in infrastructures and tools for multiagent systems. Information Systems Frontiers. 16:163-167. doi:10.1007/s10796-014-9493-6S16316716Alberola, J. M., Búrdalo, L., Julián, V., Terrasa, A., & García-Fornes, A. (2014). An adaptive framework for monitoring agent organizations. Information Systems Frontiers, 16(2). doi: 10.1007/s10796-013-9478-x .Alfonso, B., Botti, V., Garrido, A., & Giret, A. (2014). A MAS-based infrastructure for negotiation and its application to a water-right market. 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    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino

    Dinucleotide controlled null models for comparative RNA gene prediction

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    <p>Abstract</p> <p>Background</p> <p>Comparative prediction of RNA structures can be used to identify functional noncoding RNAs in genomic screens. It was shown recently by Babak <it>et al</it>. [BMC Bioinformatics. 8:33] that RNA gene prediction programs can be biased by the genomic dinucleotide content, in particular those programs using a thermodynamic folding model including stacking energies. As a consequence, there is need for dinucleotide-preserving control strategies to assess the significance of such predictions. While there have been randomization algorithms for single sequences for many years, the problem has remained challenging for multiple alignments and there is currently no algorithm available.</p> <p>Results</p> <p>We present a program called SISSIz that simulates multiple alignments of a given average dinucleotide content. Meeting additional requirements of an accurate null model, the randomized alignments are on average of the same sequence diversity and preserve local conservation and gap patterns. We make use of a phylogenetic substitution model that includes overlapping dependencies and site-specific rates. Using fast heuristics and a distance based approach, a tree is estimated under this model which is used to guide the simulations. The new algorithm is tested on vertebrate genomic alignments and the effect on RNA structure predictions is studied. In addition, we directly combined the new null model with the RNAalifold consensus folding algorithm giving a new variant of a thermodynamic structure based RNA gene finding program that is not biased by the dinucleotide content.</p> <p>Conclusion</p> <p>SISSIz implements an efficient algorithm to randomize multiple alignments preserving dinucleotide content. It can be used to get more accurate estimates of false positive rates of existing programs, to produce negative controls for the training of machine learning based programs, or as standalone RNA gene finding program. Other applications in comparative genomics that require randomization of multiple alignments can be considered.</p> <p>Availability</p> <p>SISSIz is available as open source C code that can be compiled for every major platform and downloaded here: <url>http://sourceforge.net/projects/sissiz</url>.</p
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