494 research outputs found

    Percolation approach to glassy dynamics with continuously broken ergodicity

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    We show that the relaxation dynamics near a glass transition with continuous ergodicity breaking can be endowed with a geometric interpretation based on percolation theory. At mean-field level this approach is consistent with the mode-coupling theory (MCT) of type-A liquid-glass transitions and allows to disentangle the universal and nonuniversal contributions to MCT relaxation exponents. Scaling predictions for the time correlation function are successfully tested in the F12 schematic model and facilitated spin systems on a Bethe lattice. Our approach immediately suggests the extension of MCT scaling laws to finite spatial dimensions and yields new predictions for dynamic relaxation exponents below an upper critical dimension of 6

    Innovación y madurez tecnológica en empresas e instituciones mexicanas con base en la encuesta ESIDET 2017

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    This study focuses on the low levels of innovation in Mexican companies and institutions expressed in the patent registry. The objective of this study was to know the impact of research and development activities on the ability to register patents by Mexican companies and institutions in the different states, as well as to analyze the distribution of this ability in them. The study was based on data from the survey on research and technological development ESIDET, carried out by INEGI in 2017 at the national level to 12,159 companies and 1,045 institutions. The dependent variable of interest was the ability to patent and the predictor was the level of technological maturity of organizations. The results showed in the classification of the federative entities in conglomerates according to the capacity to patent, a great heterogeneity in the number of organizations with maturity in the technological management to register patents, with a strong concentration in the CDMX. Multiple linear regression analysis showed that the ability to register patents is a function of the ability to assimilate and modify technologies, which is congruent with the trend of open innovation, using external sources of knowledge.Este documento se enfoca en los bajos niveles de innovación en las empresas e instituciones mexicanas expresado en el registro de patentes. El objetivo del presente estudio fue conocer el impacto de las actividades de investigación y desarrollo en la capacidad de registrar patentes por empresas e instituciones mexicanas en las diferentes entidades federativas, así como analizar la distribución de esta capacidad en ellas. Se partió de los datos de la encuesta sobre investigación y desarrollo tecnológico ESIDET, realizada por el INEGI en 2017 a nivel nacional a 12,159 empresas y 1,045 instituciones. La variable dependiente de interés fue la capacidad de patentar y la predictora los niveles de madurez tecnológica de las organizaciones. Los resultados mostraron en la clasificación de las entidades federativas en conglomerados en función de la capacidad de patentar, una gran heterogeneidad en el número de organizaciones con madurez en la gestión tecnológica para registrar patentes, con una fuerte concentración en la CDMX. El análisis de regresión lineal múltiple mostró que la capacidad de registrar patentes está en función de la capacidad de asimilar y modificar tecnologías, lo cual es congruente con la tendencia de la innovación abierta, empleando las fuentes externas de conocimiento

    TCRγ-Chain Gene Rearrangement by PCR-Based GeneScan: Diagnostic Accuracy Improvement and Clonal Heterogeneity Analysis in Multiple Cutaneous T-Cell Lymphoma Samples

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    Cutaneous T-cell lymphomas are a heterogeneous group of lymphomas where the tumor population emerges within a multiple subclone pattern (“clonal heterogeneity”). PCR analysis has been shown to be useful in the diagnosis of mycosis fungoides (MF) and Sézary Syndrome (SS). Focusing the attention on clonal heterogeneity, the efficacy of the multiplex/heteroduplex (HD) PCR and the GeneScan (GS) capillary electrophoresis analysis was compared in the early diagnosis of MF/SS, using a multiple sample approach. Indeed, GS demonstrated TCRγ gene rearrangement (GR) in all the 57 SS (100%) and in 123/146 (84%) of the MF samples, whereas the multiplex/HD PCR was less sensitive. An increase in clonality was observed in connection with both a worsening of the cutaneous disease (79% T1/T2; 100% T3/T4) and an increase in the histopathological score (HS<5, 76%; HS≥5, 94%). Clonal heterogeneity with adjunctive reproducible skin TCRγ-GRs was also observed. “Clonal instability,” with different GRs, was present in a small percentage of patients. Therefore, it can be concluded that GS analysis in TCRγ-GR is able to improve diagnosis in MF/SS patients and the multiple sample approach is helpful for a correct interpretation of clonal patterns in skin lesions, especially in early-stage MF and in SS skin/blood samples

    Search strings for the study of putative occupational determinants of disease

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    Objective To identify efficient PubMed search strategies to retrieve articles regarding putative occupational determinants of conditions not generally considered to be work related. Methods Based on MeSH definitions and expert knowledge, we selected as candidate search terms the four MeSH terms describing 'occupational disease', 'occupational exposure', 'occupational health' and 'occupational medicine' (DEHM) alongside 22 other promising terms. We first explored overlaps between the candidate terms in PubMed. Using random samples of abstracts retrieved by each term, we estimated the proportions of articles containing potentially pertinent information regarding occupational aetiology in order to formulate two search strategies (one more 'specific', one more 'sensitive'). We applied these strategies to retrieve information on the possible occupational aetiology of meningioma, pancreatitis and atrial fibrillation. Results Only 20.3% of abstracts were retrieved by more than one DEHM term. The more 'specific' search string was based on the combination of terms that yielded the highest proportion (40%) of potentially pertinent abstracts. The more 'sensitive' string was based on the use of broader search fields and additional coverage provided by other search terms under study. Using the specific string, the numbers of abstracts needed to read to find one potentially pertinent article were 1.2 for meningioma, 1.9 for pancreatitis and 1.8 for atrial fibrillation. Using the sensitive strategy, the numbers needed to read were 4.4 for meningioma, 8.9 for pancreatitis and 10.5 for atrial fibrillation. Conclusions The proposed strings could help health care professionals explore putative occupational aetiology for diseases that are not generally thought to be work relate

    Epstein-Barr Virus in Cutaneous T-Cell Lymphomas: Evaluation of the Viral Presence and Significance in Skin and Peripheral Blood

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    The importance of viral agents in the development of cutaneous T-cell lymphomas (CTCL) is still debated. For this purpose, we retrospectively evaluated the Epstein-Barr virus (EBV) presence in Sézary syndrome (SS), mycosis fungoides (MF), inflammatory dermatoses (ID), and healthy donors (HD) using different approaches: EBV-DNA was quantified in skin biopsies and peripheral blood using real-time PCR, EBV-encoded small RNA (EBER) transcripts were detected by in situ hybridization (ISH), and latent membrane protein1-2 antigens were detected by immunohistochemistry. Skin biopsies were EBV-DNA-positive in 8/30 (27%) SS, 7/71 (10%) MF, and 2/18 (11%) ID patients and in none of the 25 normal skin samples. Positive mRNA (EBER) signals, always confined to cerebriform T lymphocytes, were found in 5/30 SS patients (17%), whereas signals in all MF and ID patients were negative. The presence of EBV-DNA in skin and blood samples was associated with a significantly lower survival in MF/SS patients. In evaluating EBV serological status, most (>70%) SS, MF, and ID patients showed a serological reactivation demonstrated by the presence of anti-EA IgG. In conclusion, although the finding of EBV-DNA in CTCL does not prove its etiopathogenetic role and may be related instead to immunosuppression, our study demonstrates that it has prognostic relevance

    Solar radiation effects on the Sardinia Radio Telescope performances

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    The Sardinia Radio Telescope, a 64-metre diameter fully steerable radio telescope operated by INAF, will be upgraded in order to extend its current operating frequency range 0.3-26.5 GHz up to 116 GHz, thanks to a National Operational Program (PON) funding assigned to INAF by the Italian Ministry of University and Research. The PON project is organized in nine Work Packages, one of which is dedicated to the accomplishment of a sophisticated metrology system designed to monitor the cause of the pointing errors and the reflector surface deformations. The entire antenna structure will therefore be equipped with a network of sensors, like thermal sensors, inclinometers, accelerometers, collimators, anemometers, strain gauges and others, to study environmental stresses and how they affect the SRT performances. This work is devoted to the investigation of the thermal stress effects produced by solar radiation. In particular, two analyses are carried out to confirm the relevance of a thorough temperature monitoring system, both conducted using Finite Element Analysis. First, a possible approach for the simulation of realistic thermal scenarios due to insolation is proposed and the effects on the pointing accuracy are analysed. Second, a feasible method to study the impacts that a differential heating of the Back Up Structure (BUS) produces on the radio telescope main reflector surface is presented. Finally, these effects are analysed as optical aberrations and modelled in terms of Zernike polynomials
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