873 research outputs found

    Analysis of heavy spin--3/2 baryon--heavy spin--1/2 baryon--light vector meson vertices in QCD

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    The heavy spin--3/2 baryon--heavy spin--1/2 baryon vertices with light vector mesons are studied within the light cone QCD sum rules method. These vertices are parametrized in terms of three coupling constants. These couplings are calculated for all possible transitions. It is shown that correlation functions for these transitions are described by only one invariant function for every Lorenz structure. The obtained relations between the correlation functions of the different transitions are structure independent while explicit expressions of invariant functions depend on the Lorenz structure.Comment: 17 Pages, 6 Figures and 4 Table

    Thymomas: a review.

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    Thymomas are neoplasma of thymic epithelial cells. They may be benign or malignant and may associate with locai ìnvasiveness and paraneoplastic diseases. Myasthenia gravis is often associated with thymomas, bui this is not thè rule. Several classifications have been proposed: some of them follow thè histopathological findings (Rosai and Levine, Snover, Marino and Muller- Hermelink classification), other emphasizes thè clinic-pathological stage (Masaoka, Verley and Hollmann stadiation). One third of thymomas is asymptomatic. Diagnosis is made often by plain X-ray and confirmed by Computed Tomography or fine needle biopsy. Surgery is effective in 100% of noninvasive cases and in 58% of invasive ones. Radio and chemotherapy are recommended only in advanced or inoperable stages

    The 4 K outer cryostat for the CUORE experiment: construction and quality control

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    The external shell of the CUORE cryostat is a large cryogen-free system designed to host the dilution refrigerator and the bolometers of the CUORE experiment in a low radioactivity environment. The three vessels that form the outer shell were produced and delivered to the Gran Sasso underground Laboratories in July 2012. In this paper, we describe the production techniques and the validation tests done at the production site in 2012.Comment: 11 pages, 13 figures; to appear in NIM

    Searches for axioelectric effect of solar axions with BGO-scintillator and BGO-bolometer detectors

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    A search for axioelectric absorption of 5.5 MeV solar axions produced in the p+d3He+γ (5.5 MeV)p + d \rightarrow {^3\rm{He}}+\gamma~(5.5~ \rm{MeV}) reaction has been performed with a BGO detectors. A model-independent limit on the product of axion-nucleon gAN3g_{AN}^3 and axion-electron gAeg_{Ae} coupling constants has been obtained: gAe×gAN3<1.9×1010| g_{Ae}\times g_{AN}^3|< 1.9\times 10^{-10} for 90\% C.L..Comment: 5 pages, 3 figures, Proceedings of the 10th Patras Workshop on Axions, WIMPs and WISP 29 June - 4 July 2014, CERN, Geneva, Switzerlan

    The CUORE Cryostat: A 1-Ton Scale Setup for Bolometric Detectors

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    The cryogenic underground observatory for rare events (CUORE) is a 1-ton scale bolometric experiment whose detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. This will be the largest bolometric mass ever operated. The experiment will work at a temperature around or below 10 mK. CUORE cryostat consists of a cryogen-free system based on pulse tubes and a custom high power dilution refrigerator, designed to match these specifications. The cryostat has been commissioned in 2014 at the Gran Sasso National Laboratories and reached a record temperature of 6 mK on a cubic meter scale. In this paper, we present results of CUORE commissioning runs. Details on the thermal characteristics and cryogenic performances of the system will be also given.Comment: 7 pages, 2 figures, LTD16 conference proceedin

    Routine serum biomarkers, but not dual-energy X-ray absorptiometry, correlate with cortical bone mineral density in children and young adults with chronic kidney disease

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    BACKGROUND: Biomarkers and dual-energy X-ray absorptiometry (DXA) are thought to be poor predictors of bone mineral density (BMD). The Kidney Disease: Improving Global Outcomes guidelines suggest using DXA if the results will affect patient management, but this has not been studied in children or young adults in whom bone mineral accretion continues to 30 years of age. We studied the clinical utility of DXA and serum biomarkers against tibial cortical BMD (CortBMD) measured by peripheral quantitative computed tomography, expressed as Z-score CortBMD, which predicts fracture risk. METHODS: This was a cross-sectional multicentre study in 26 patients with CKD4 and 5 and 77 on dialysis. RESULTS: Significant bone pain that hindered activities of daily living was present in 58%, and 10% had at least one low-trauma fracture. CortBMD and cortical mineral content Z-scores were lower in dialysis compared with CKD patients (P = 0.004 and P = 0.02). DXA BMD hip and lumbar spine Z-scores did not correlate with CortBMD or biomarkers. CortBMD was negatively associated with parathyroid hormone (PTH; r = -0.44, P < 0.0001) and alkaline phosphatase (ALP; r = -0.22, P = 0.03) and positively with calcium (Ca; r = 0.33, P = 0.001). At PTH <3 times upper limit of normal, none of the patients had a CortBMD below -2 SD (odds ratio 95% confidence interval 7.331 to infinity). On multivariable linear regression PTH (β = -0.43 , P < 0.0001), ALP (β = -0.36, P < 0.0001) and Ca (β = 0.21, P = 0.005) together predicted 57% of variability in CortBMD. DXA measures did not improve this model. CONCLUSIONS: Taken together, routinely used biomarkers, PTH, ALP and Ca, but not DXA, are moderate predictors of cortical BMD. DXA is not clinically useful and should not be routinely performed in children and young adults with CKD 4-5D

    First array of enriched Zn82^{82}Se bolometers to search for double beta decay

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    The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in 82^{82}Se, the Zn82^{82}Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn82^{82}Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-0

    CUPID-0: the first array of enriched scintillating bolometers for 0decay investigations

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    The CUPID-0 detector hosted at the Laboratori Nazionali del Gran Sasso, Italy, is the first large array of enriched scintillating cryogenic detectors for the investigation of82Se neutrinoless double-beta decay (0). CUPID-0 aims at measuring a background index in the region of interest (RoI) for 0at the level of 10- 3 counts/(keV kg years), the lowest value ever measured using cryogenic detectors. CUPID-0 operates an array of Zn82Se scintillating bolometers coupled with bolometric light detectors, with a state of the art technology for background suppression and thorough protocols and procedures for the detector preparation and construction. In this paper, the different phases of the detector design and construction will be presented, from the material selection (for the absorber production) to the new and innovative detector structure. The successful construction of the detector lead to promising preliminary detector performance which is discussed here

    Ingeniería estadística aplicada a un programa de conservación y promoción de la audición

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    Statistical Engineering is defined as “a discipline dedicated to the art and science of solving complex problems that require data and data analysis”. It focuses on the study of the systematic integration of statistical concepts, methods and tools, often with other relevant disciplines, to solve complex and often unstructured problems. The International Statistical Engineering Association (ISEA) proposes a global methodology based on the scientific method and the use of statistical thinking to address this type of problem in different phases. In this article, a case of application of Statistical Engineering to the problem related to the hearing health of adolescents is described. Specifically, the research aimed to find a scientific answer to the high percentage of young people rejected for employment in Argentina due to hearing disorders, without clinical justification. This problem gave rise to a multidisciplinary and multi-institutional program that needed to be approached from different areas, including audiological, psychosocial, acoustic, genetic and statistical aspects. The strategies and techniques carried out for the analysis of the collected data are highlighted, which allowed establishing an educational intervention campaign to make young people aware of the harmful effects of noise on hearing.La Ingeniería Estadística se define como “una disciplina dedicada al arte y a la ciencia de resolver problemas complejos que requieren datos y análisis de datos”. Se focaliza en el estudio de la integración sistemática de conceptos, métodos y herramientas estadísticas, a menudo con otras disciplinas relevantes, para resolver problemas complejos y muchas veces no estructurados.&nbsp;La Asociación Internacional de Ingeniería Estadística (ISEA por sus siglas en inglés), propone una metodología global basada en el método científico y en el uso del pensamiento estadístico para abordar este tipo de problemas en diferentes fases. En este artículo se describe un caso de aplicación de Ingeniería Estadística a la problemática relacionada con la salud auditiva de adolescentes. Específicamente, la investigación tenía por objetivo encontrar una respuesta científica al alto porcentaje de jóvenes rechazados en el ingreso laboral en Argentina por afecciones auditivas, sin justificación clínica. Este problema dio origen a un&nbsp;Programa multidisciplinario y&nbsp;multiinstitucional&nbsp;que necesitó ser abordado desde diferentes áreas, incluyendo aspectos audiológicos, psicosociales, acústicos, genéticos y estadísticos. Se destacan las estrategias y técnicas llevadas a cabo para el análisis de los datos relevados que permitió establecer una campaña educativa de intervención para concientizar a los jóvenes sobre los efectos nocivos del ruido para la audición
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