679 research outputs found

    Cherenkov and Scintillation Light Separation in Organic Liquid Scintillators

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    The CHErenkov / Scintillation Separation experiment (CHESS) has been used to demonstrate the separation of Cherenkov and scintillation light in both linear alkylbenzene (LAB) and LAB with 2g/L of PPO as a fluor (LAB/PPO). This is the first such demonstration for the more challenging LAB/PPO cocktail and improves on previous results for LAB. A time resolution of 338 +/- 12 ps FWHM results in an efficiency for identifying Cherenkov photons in LAB/PPO of 70 +/- 3% and 63 +/- 8% for time- and charge-based separation, respectively, with scintillation contamination of 36 +/- 5% and 38 +/- 4%. LAB/PPO data is consistent with a rise time of 0.75 +/- 0.25 ns

    Characterization of light production and transport in tellurium dioxide crystals

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    Simultaneous measurement of phonon and light signatures is an effective way to reduce the backgrounds and increase the sensitivity of CUPID, a next-generation bolometric neutrinoless double-beta decay (0νββ) experiment. Light emission in tellurium dioxide (TeO2) crystals, one of the candidate materials for CUPID, is dominated by faint Cherenkov radiation, and the high refractive index of TeO2 complicates light collection. Positive identification of 0νββ events therefore requires high-sensitivity light detectors and careful optimization of light transport. A detailed microphysical understanding of the optical properties of TeO2 crystals is essential for such optimization. We present a set of quantitative measurements of light production and transport in a cubic TeO2 crystal, verified with a complete optical model and calibrated against a UVT acrylic standard. We measure the optical surface properties of the crystal, and set stringent limits on the amount of room-temperature scintillation in TeO2 for β and α particles of 5.3 and 8 photons/MeV, respectively, at 90% confidence. The techniques described here can be used to optimize and verify the particle identification capabilities of CUPID

    Mental health, substance abuse, prison victimization and suicide attempts amongst incarcerated women

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    Worldwide, incarcerated women are known to suffer adverse experiences that might increase the risk of suicide attempts during incarceration. The present investigation examines the prevalence of suicide attempts amongst incarcerated women in Spain and the factors associated with this. Between January and March of 2017 a total of 174 women, enrolled from two prisons in the southeast of Spain, completed anonymous self-report measures of demographic variables, penitentiary and sentence-related variables, mental distress (including depression, anxiety and stress), perceived social support, substance use (including alcohol, cannabis, cocaine, amphetamine, heroin and hallucinogens), prison victimization (property, verbal, physical and sexual victimization) and suicide attempts. Overall, 15.5 percent of women reported they had attempted suicide during their current incarceration. Compared with women who did not report suicide attempts, multivariate analysis showed that women reporting suicide attempts were more likely to report lower education levels, in-prison substance use, victimization and higher levels of mental distress. In order to prevent suicide amongst incarcerated women, victimization in all its forms, emotional distress and drug abuse in women with lower education levels, should be considered highly targetable variables.</p

    Análisis del espesor coroideo en pacientes con queratocono

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    Objective. To determine and compare choroidal thickness (CT) in keratoconus (KC) patients using Enhanced Depth Imaging (EDI) OCT. Methods. A comparative cross-sectional study including 26 patients with KC and 26 healthy controls assessed with Pentacam and EDI-OCT. CT was measured manually with the Caliper function at thirteen locations at 500 µm regular intervals. Results. The average CT in T6 was 253.96 ± 88.95 μm in the KC group, and of 309.39 ± 94.11 μm in the control group (p <0.041). No significant differences in mean CT were observed in the rest of the points, including the subfoveal CT (M), 351.48 ± 106.3 vs 365.35 ± 114.6 μm, (p = 0.66). No correlation was observed between the mean subfoveal CT (M), the mean CT in the KC group, and the values of K1 (p = 0.977 and p = 0.498 respectively), K2 (p = 0.450 and p = 0.656), corneal asphericity (Q ) (p = 0.986 and p = 0.902), minimal pachymetry (Pachy) (p = 0.408 and p = 0.688), keratoconus index (KI) (p = 0.601 and p = 0.217), vertical asymmetry index (VAT) (p = 0.296 and p = 0.523), staging of KC (TKC) (p = 0.549 and p = 0.08) and corneal apex morphology. Conclusion. Significant lower CT was found in the KC group in T6 (3000 μm temporal to the fovea). No significant difference of CT values in KC patients and healthy subjects was found in the other twelve measurement locations.We found no association between the refractive and keratometric indexes obtained by corneal topography and subfoveal CT.Objetivo. Determinar y comparar el grosor de la coroides (CT) en pacientes con queratocono (KC) usando OCT con Enhanced Depth Imaging (EDI). Métodos. Estudio comparativo transversal que incluye 26 pacientes con KC y 26 controles sanos evaluados con Pentacam y EDI-OCT. El KC fue medido manualmente con la función Caliper en trece puntos a intervalos regulares de 500 µm. Resultados. El promedio de CT en T6 fue de 253,96 ± 88,95 μm en el grupo KC, y de 309,39 ± 94,11 μm en el grupo de control (p <0,041). No se observaron diferencias significativas en la media de CT en el resto de los puntos, incluyendo el CT subfoveal (M), 351.48 ± 106.3 vs 365.35 ± 114.6 μm, (p = 0.66). No se observó ninguna correlación entre la media de CT (M) subfoveal, la media de CT en el grupo KC, y los valores de K1 (p = 0,977 y p = 0,498 respectivamente), K2 (p = 0,450 y p = 0,656), la asfericidad corneal (Q) (p = 0,986 y p = 0. 902), paquimetría mínima (Pachy) (p = 0,408 y p = 0,688), índice de queratocono (KI) (p = 0,601 y p = 0,217), índice de asimetría vertical (VIA) (p = 0,296 y p = 0,523), estadificación del KC (TKC) (p = 0,549 y p = 0,08) y morfología del ápice corneal. Conclusión. Se observó un CT significativamente menor en el grupo KC en T6 (3000 μm temporal a la fóvea). No se encontraron diferencias significativas entre los valores del CT en los pacientes con KC y en los sujetos sanos en los 12 puntos de medida restantes. No se encontró ninguna asociación entre los índices refractivos y queratométricos obtenidos por la topografía corneal y el CT subfoveal

    Neuromuscular and mobility responses to a vibration session in hypoxia in multiple sclerosis

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    The aim of this study was to investigate the acute effects of vibration training (WBVT) under hypoxic and normoxic conditions on the voluntary rate of force development (RFD), balance and muscle oxygen saturation (SMO2) in persons with Multiple Sclerosis (MS). 10 participants completed the study (30 % males, 44.4±7.7 years, 164.3±8.9cm, 65.2±11.1kg, 2.5±1.3 Expanded Disability Status Scale, 24.1± 4.0 kg.m− 2 BMI). Maximal force, RFD during isometric knee extension, static balance with eyes open and closed and sit-to-stand test were evaluated before and immediately after one session of WBVT (12 60-s bout of vibration; frequency 35Hz; amplitude 4mm; 1-min rest intervals) under both normoxic and hypoxic conditions. In addition, SMO2 of the gastrocnemius lateralis was assessed during each condition. No changes were found in force, static balance and sit-to-stand test. Time-to-peak RFD increased in the left leg (p = 0.02) and tended to increase in the right leg (p = 0.06) after the hypoxic session. SMO2 resulted in significant increases from the initial to final intervals of the WBVT under both hypoxic and normoxic conditions (p < 0.05). Increases in SMO2 during WBVT demonstrates muscle work that may contribute to the observed muscle adaptations in long-term WBVT programs without inducing decreases in neuromuscular activation, physical function and balance within a session
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