2,627 research outputs found

    Electronic contribution to the oscillations of a gravitational antenna

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    We carefully analyse the contribution to the oscillations of a metallic gravitational antenna due to the interaction between the electrons of the bar and the incoming gravitational wave. To this end, we first derive the total microscopic Hamiltonian of the wave-antenna system and then compute the contribution to the attenuation factor due to the electron-graviton interaction. As compared to the ordinary damping factor, which is due to the electron viscosity, this term turns out to be totally negligible. This result confirms that the only relevant mechanism for the interaction of a gravitational wave with a metallic antenna is its direct coupling with the bar normal modes.Comment: 25 pages, no figure

    A novel mutation in SACS gene in a family from southern Italy

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    A form of autosomal recessive spastic ataxia (ARSACS) has been described in the Charlevoix and Saguenay regions of Quebec. So far a frameshift and a nonsense mutation have been identified in the SACS gene. The authors report a new mutation (1859insC), leading to a frameshift with a premature termination of the gene product sacsin, in two sisters from consanguineous parents. The phenotype is similar to previously described patients with ARSACS

    TBC1D24 and non-syndromic autosomal dominant hearing loss: the identification of an additional Italo-American family carrying the p.(S178L) mutation

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    Hearing loss is the most common sensorineural disorder, affecting approximately 1:1000 new-borns. In developed countries, more than half of the cases of congenital hearing loss are due to genetic causes and both syndromic and non-syndromic forms may be recognized. Approximately 20% of the cases of nonsyndromic hearing loss are inherited according to an autosomal dominant pattern. Autosomal dominant hereditary hearing loss (ADHHL) is characterized by a wide genetic heterogeneity and by inter- and intrafamilial clinical variability, making genotype-phenotype correlations extremely complicated. Here we describe a large multi-generation Italo-American kindred affected by ADHHL. After a complete clinical evaluation and hearing function assessment through pure tone audiometry, the proband underwent a multiple-step genetic testing. Eventually, whole exome sequencing was performed on his and other selected family members’ DNA leading to the identification of a heterozygous missense variant in the TBC1D24 gene. Mutations in this gene have been associated with a variety of conditions that are inherited in an autosomal recessive pattern and that may or may not include hearing loss. Interestingly, the variant identified in our kindred is the only mutation in the TBC1D24 gene that has been associated with ADHHL in previous studies. Our case report confirms the role of the TBC1D24 gene and specifically of the p.(S178L) variant in the etiopathogenesis of ADHHL, underlining once again the clinical variability associated with variants in this gene

    CMS DT Chambers: Optimized Measurement of Cosmic Rays Crossing Time in absence of Magnetic Field

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    Two spare drift chambers produced in the I.N.F.N. Legnaro Laboratory (Padova, Italy) for the barrel muon spectrometer of the LHC CMS experiment have been extensively tested using cosmic-ray muons. A fitting algorithm was developed to optimize the determination of the time of passage of the particle. A timing resolution of ≈\approx2~ns has been obtained. The algorithm permits the measurement of the track reconstruction precision of the chambers by using cosmic-ray data with the same accuracy obtained using high-energy test-beam data

    A manifestação das diferentes modalidades no emprego do verbo modal <i>poder</i> em portuguĂȘs e em espanhol: AnĂĄlise do discurso de autoajuda

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    Resumen. Este trabajo tiene por objetivo investigar el comportamiento del verbo modal poder como verbo auxiliar en dos lenguas romances, el portugu&eacute;s brasile&ntilde;o y el espa&ntilde;ol peninsular, en textos escritos de ambos idiomas. El trabajo se desa&shy;rrolla desde una perspectiva funcionalista del lenguaje, m&aacute;s espec&iacute;ficamente la gram&aacute;tica funcional holandesa, y se apoya en la clasificaci&oacute;n de modalidad propuesta por Hengeveld (2004), que considera dos criterios principales: la meta de la evaluaci&oacute;n y el dominio sem&aacute;ntico de la evaluaci&oacute;n. Teniendo en cuenta esta clasificaci&oacute;n, analizamos el uso del verbo auxiliar poder en el discurso de autoayuda, que goza, en la actualidad, de gran popularidad en varias partes del mundo. Aunque el verbo auxiliar poder sea esencialmente un modal epist&eacute;mico en el portugu&eacute;s (seg&uacute;n Neves 1999-2000) &mdash;lo cual, en la clasificaci&oacute;n de Hengeveld (2004) corresponde a la modalidad epist&eacute;mica orientada hacia el evento&mdash; los datos analizados demuestran que, en funci&oacute;n de la naturaleza esencialmente optimista del discurso investigado &mdash;el discurso de autoayuda&mdash; dicho auxiliar act&uacute;a predominantemente como modal facultativo orientado hacia el participante. Tal resultado pone de relieve la importancia de considerar el contexto en el que el verbo modal aparece para evaluar los efectos de sentido asociados a su uso. Palabras clave: modalidad, verbo poder, discurso de autoayuda, funcionalismo. Abstract. This paper aims to investigate the behavior of the modal verb poder as an auxiliary verb in text written in both two Romance languages, Brazilian Portuguese and Iberian Spanish. This research follows a functionalist language approach, more precisely the Dutch Functional Grammar tradition, based on the modality classification proposed by Hengeveld (2004). This author considers two main criteria: target of evaluation, and semantic domain of evaluation. Considering this classification, we analyze the use of the auxiliary verb poder in a corpus of self-help discourses, which currently enjoy enormous popularity in various parts of the world. Although in Portuguese the auxiliary verb poder is essentially an epistemic modal (cf. Neves 1999-2000) &mdash;which, according to the Hengeveld (2004), corresponds to the event-oriented epistemic modality&mdash;. However, our analysis show that, given the essentially optimistic nature of the discourse analyzed, the self-help discourse, the previously mentioned modal verb (poder) behaves predominantly as a participant-oriented facultative modal. This result demonstrates the importance of considering the context of occurrence of the verb poder in order to evaluate the effects of meaning associated with its use. Keywords: modality, verb poder, self-help discourse, functionalism. Resumo. Este trabalho tem por objetivo investigar o comportamento do verbo modal poder na condi&ccedil;&atilde;o de verbo auxiliar em duas l&iacute;nguas rom&acirc;nicas, o portugu&ecirc;s brasileiro e o espanhol peninsular, em textos escritos dos dois idiomas. O trabalho desenvolve-se orientado por uma abordagem funcionalista da linguagem, mais precisamente a Gram&aacute;tica Funcional de linha holandesa, tomando como base a classifica&ccedil;&atilde;o de modalidade proposta por Hengeveld (2004), que considera dois crit&eacute;rios principais: alvo de avalia&ccedil;&atilde;o e dom&iacute;nio sem&acirc;ntico de avalia&ccedil;&atilde;o. Considerando essa classifica&ccedil;&atilde;o, analisamos o emprego do auxiliar poder no discurso de autoajuda, que desfruta, atualmente, de grande popularidade em v&aacute;rias partes do mundo. Embora o verbo auxiliar poder, na l&iacute;ngua portuguesa, seja essencialmente um modal epist&ecirc;mico (Neves 1999-2000) &mdash;o que, na classifica&ccedil;&atilde;o de Hengeveld (2004), corresponde &agrave; modalidade epist&ecirc;mica orientada para o evento&mdash; os dados analisados revelam que, dada a natureza essencialmente otimista do discurso estudado &mdash;o discurso de autoajuda&mdash; o auxiliar comporta-se predominantemente como modal facultativo orientado para o participante. Tal resultado evidencia a import&acirc;ncia de considerarmos o contexto de ocorr&ecirc;ncia do verbo poder para avaliar os efeitos de sentido associados a seu emprego. Palavras-chave: modalidade, verbo poder, discurso de autoajuda, funcionalismo.</p

    Virological investigation on aerosol from waste depuration plants

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    Aerosol from activated mud decontamination plants used for the treatment of urban sewage can represent a vehicle for bacteria, virus and fungi. As a result, they become an infective hazard for plant personnel, the general population residing in the surrounding area and the occasional visitor. The present investigation focuses on the identification of enteric-type viruses in this kind of aerosol. The following methods were employed on 214 samples collected in the 1999-2000 period: cell culture (BGM, RD, Hep-2), electron microscopy, and polymerase chain reaction (PCR). Cytopathic effect was mild in 180 samples, and severe in 14, upon their first passage in culture. Virus identification was based on positivity to both electron microscopy (EM) and PCR. Thus, one positive sample was recognized to be of enteric-type virus and two positive samples were recognized as reovirus-type. All samples were negative for Norwalk-type virus or HAV. There was considerable discrepancy between electron microscopy and PCR concerning the number of enteric-type viruses recognized. A possible explanation is contamination with animal-type enterovirus

    The p.Cys169Tyr variant of connexin 26 is not a polymorphism

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    Mutations in the GJB2 gene, which encodes the gap junction protein connexin 26 (Cx26), are the primary cause of hereditary prelingual hearing impairment. Here, the p.Cys169Tyr missense mutation of Cx26 (Cx26C169Y), previously classified as a polymorphism, has been identified as causative of severe hearing loss in two Qatari families. We have analyzed the effect of this mutation using a combination of confocal immunofluorescence microscopy and molecular dynamics simulations. At the cellular level, our results show that the mutant protein fails to form junctional channels in HeLa transfectants despite being correctly targeted to the plasma membrane. At the molecular level, this effect can be accounted for by disruption of the disulfide bridge that Cys169 forms with Cys64 in the wild-type structure (Cx26WT). The lack of the disulfide bridge in the Cx26C169Y protein causes a spatial rearrangement of two important residues, Asn176 and Thr177. In the Cx26WT protein, these residues play a crucial role in the intra-molecular interactions that permit the formation of an intercellular channel by the head-to-head docking of two opposing hemichannels resident in the plasma membrane of adjacent cells. Our results elucidate the molecular pathogenesis of hereditary hearing loss due to the connexin mutation and facilitate the understanding of its role in both healthy and affected individuals

    Measurement of Drift Velocity in the CMS Barrel Muon Chambers at the CMS Magnet Test Cosmic Challenge

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    This note reports the results of the analysis performed on the data collected by the CMS Barrel Muon system during the Magnet Test-Cosmic Challenge, aimed to study the Drift Tube chambers behavior at the nominal value of the CMS magnetic field. In particular, the analysis is devoted to the study of the drift velocity in the various equipped regions of the apparatus. It is shown that the drift velocity is significantly affected by the presence of a residual magnetic field in the chamber volume only in the innermost stations, MB1, of Wheel+2; where the maximal variation inside the chamber is of 4 percent, which does not prevent a good functionality of the DT trigger even in this most critical region
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