61 research outputs found

    Scintillator ageing of the T2K near detectors from 2010 to 2021

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    The T2K experiment widely uses plastic scintillator as a target for neutrino interactions and an active medium for the measurement of charged particles produced in neutrino interactions at its near detector complex. Over 10 years of operation the measured light yield recorded by the scintillator based subsystems has been observed to degrade by 0.9–2.2% per year. Extrapolation of the degradation rate through to 2040 indicates the recorded light yield should remain above the lower threshold used by the current reconstruction algorithms for all subsystems. This will allow the near detectors to continue contributing to important physics measurements during the T2K-II and Hyper-Kamiokande eras. Additionally, work to disentangle the degradation of the plastic scintillator and wavelength shifting fibres shows that the reduction in light yield can be attributed to the ageing of the plastic scintillator. The long component of the attenuation length of the wavelength shifting fibres was observed to degrade by 1.3–5.4% per year, while the short component of the attenuation length did not show any conclusive degradation

    Cervical pessary vs vaginal progesterone for prevention of preterm birth in women with twin pregnancy and short cervix: economic analysis following randomized controlled trial

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    OBJECTIVE:To compare the cost-effectiveness of cervical pessary vs vaginal progesterone to prevent preterm birth and neonatal morbidity in women with twin pregnancy and a short cervix. METHODS:Between 4 March 2016 and 3 June 2017, we performed this economic analysis following a randomized controlled trial (RCT), performed at My Duc Hospital, Ho Chi Minh City, Vietnam, that compared cervical pessary to vaginal progesterone in women with twin pregnancy and cervical length < 38 mm between 16 and 22 weeks of gestation. We used morbidity-free neonatal survival as a measure of effectiveness. Data on pregnancy outcome, maternal morbidity and neonatal complications were collected prospectively from medical files; additional information was obtained via telephone interviews with the patients. The incremental cost-effectiveness ratio was calculated as the incremental cost required to achieve one extra surviving morbidity-free neonate in the pessary group compared with in the progesterone group. Probabilistic and one-way sensitivity analyses were also performed. RESULTS:During the study period, we screened 1113 women with twin pregnancy, of whom 300 fulfilled the inclusion criteria of the RCT and gave informed consent to participate. These women were assigned randomly to receive cervical pessary (n = 150) or vaginal progesterone (n = 150), with two women and one woman, respectively, being lost to follow-up. The rate of morbidity-free neonatal survival was significantly higher in the pessary group compared with the progesterone group (n = 241/296 (81.4%) vs 219/298 (73.5%); relative risk, 1.11 (95% CI, 1.02-1.21), P = 0.02). The mean total cost per woman was 3146 € in the pessary group vs 3570 € in the progesterone group (absolute difference, -424 € (95% CI, -842 to -3 €), P = 0.048). The cost per morbidity-free neonate was significantly lower in the pessary group compared with that in the progesterone group (2492 vs 2639 €; absolute difference, -147 € (95% CI, -284 to 10 €), P = 0.035). CONCLUSION:In women with twin pregnancy and a short cervix, cervical pessary improves significantly the rate of morbidity-free neonatal survival while reducing costs, as compared with vaginal progesterone. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.K. D. Le, L. K. Nguyen, L. T. M. Nguyen, B. W. J. Mol, V. Q. Dan

    Optimization of normally-off β-Ga2O3 MOSFET with high Ion and BFOM: A TCAD study

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    A combination of recessed-gate and gate-field plate in lateral β-Ga2O3 metal–oxide–semiconductor field-effect transistor (MOSFET) is proposed in the Technology Computer Aided Design study to improve its ON resistance (RON) and breakdown voltage. Enhancement-mode (E-mode) is achieved by controlling the thickness of the recessed-gate. Lateral E-mode β-Ga2O3 MOSFET achieves a saturation current density near 120 mA/mm, ION/IOFF ratio ∼109, RON ∼91 Ω mm, and breakdown voltage of 1543 V. The optimized structure results in a prediction of a power figure-of-merit of 261 MW/cm2 in a horizontal E-mode β-Ga2O3 MOSFET

    Reconciling general and safety-specific transformational leadership: a paradox perspective

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    Research exploring the relationship between transformational leadership and safety has used transformational leadership in context-free (e.g., “general transformational leadership,” or GTL) and context-specific forms (e.g., “safety-specific transformational leadership,” or SSTL), assuming these constructs are theoretically and empirically equivalent. In this paper, we draw on paradox theory (Schad et al., 2016; Smith & Lewis, 2011) to reconcile the relationship between these two forms of transformational leadership and safety. We do so by (1) investigating whether GTL and SSTL are empirically distinguishable, (2) testing the relative importance of GTL and SSTL in explaining variance in context-free work outcomes (i.e., in-role performance, organizational citizenship behaviors) and context-specific (i.e., safety compliance, safety participation), and (3) examining the extent to which perceived safety concern in the work environment renders GTL and SSTL distinguishable. Two studies (one cross-sectional, one shortterm longitudinal) show that GTL and SSTL are psychometrically distinct albeit highly correlated. Furthermore, SSTL explained statistically more variance than GTL in both safety participation and organizational citizenship behaviors, whereas GTL explained more variance in in-role performance than did SSTL. However, GTL and SSTL were only distinguishable in lowconcern contexts but not high-concern contexts. These findings challenge the “either-or” (vs. “both-and”) approach to considering safety and performance, cautioning researchers to consider nuanced differences in context-free and context-specific forms of leadership and to avoid further proliferation of often redundant context-specific operationalizations of leadership

    Long-Term Heavy Metal Retention by Mangroves and Effect on Its Growth: A Field Inventory and Scenario Simulation

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    The ability of mangroves in taking up and storing heavy metal (HM) helps in reducing HM pollution. However, HMs likewise adversely affect the growth of mangroves. We assess the effects of the long-term soil HMs enrichment on the growth of Rhizophora apiculata forest in the Can Gio Mangrove Forest (Southern Vietnam) in different environmental conditions of soil salinity, ground elevation, and tree density based on a novel set of measured data. These data were analyzed and were used to calibrate and validate for a tree growth model with influencing factors salinity, elevation, tree density, and heavy metals content. Three scenario simulations were performed to predict the mangrove dynamics under different levels of heavy metal pollution in combined environmental conditions of salinity and elevation. Simulation results show the decline of total forest biomass from 1,750,000 tons (baseline scenario with no HM pollution) down to 850,000 tons and 350,000 tons for the current HM pollution and double HM pollution scenarios, respectively. Both data analysis and simulations have shown that although mangroves can assist in reducing HM pollution, the quality and health of this ecosystem will be severely affected if the environment is excessively polluted. In addition, a data-and-model driven management tool is devised for the sustainable management of the mangrove environmental resources

    The Vietnamese population of Megophrys kuatunensis (Amphibia: Megophryidae) represents a new species of Asian horned frog from Vietnam and southern China

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    The Asian frog genus Megophrys is a diverse group of morphologically conserved, forest-dwelling frogs. The genus harbours highly localised species diversification and new species continue to be described on a regular basis. We examined the taxonomic status of a population of Megophrys frogs from the Hoang Lien Range in northern Vietnam and southern China previously identified as M. kuatunensis (subgenus Panophrys). Preliminary phylogenetic analyses using a fragment of 16S rDNA places the species in question within the Megophrys (subgenus Panophrys) species group, a primarily Chinese radiation within the genus. On the basis of morphological, molecular and bioacoustic data, we conclude that this population does not represent M. kuatunensis, or any known species in the genus. We herein describe this species of Megophrys as new. Known only from Sa Pa District, Lao Cai Province in Vietnam and Jinping County, Yunnan Province in China, the new species is likely to be threatened by ongoing deforestation in the region. We provide an updated species description of M. kuatunensis based on type specimens, and suggest that M. kuatunensis is likely to be restricted to eastern China

    Phytophthora stem rot of purple passionfruit in Vietnam

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    In August 2012 a severe stem rot (stem canker) disease was observed in a purple-fruit variety of passionfruit, Passiflora edulis, in Nghe An province, Vietnam. The stem rot progressed rapidly along the stem affecting branches and fruit, leading to chlorosis, wilting and death of the distal part of the stem. It did not progress below the graft junction into the stem or roots of the rootstock, Passiflora edulis var. flavicarpa. The disease spread within and between plantings causing 100 % loss of some plantings. Phytophthora nicotianae was consistently isolated from diseased tissue and the morphological identification was confirmed by sequencing, and two cultures were deposited in the Murdoch University Culture Collection as MUCC707 and MUCC708. The former culture proved pathogenic in stem inoculations and P. nicotianae was reisolated fulfilling Koch’s postulates. This report represents a new record of Phytophthora stem rot of purple passionfruit in Vietnam
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