65 research outputs found

    The muon system of the Daya Bay Reactor antineutrino experiment

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    Improved Measurement of Electron Antineutrino Disappearance at Daya Bay

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    State and irrigation: archeological and textual evidence of water management in late Bronze Age China

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    Ancient China remains an important case to investigate the relationship between statecraft development and ‘total power.’ While important economic and social developments were achieved in the late Neolithic, it was not until the late Bronze Age (first millennium BC) that state-run irrigation systems began to be built. Construction of large-scale irrigation projects, along with walls and defensive facilities, became vital to regional states who were frequently involved in chaotic warfare and desperate to increase food production to feed the growing population. Some of the irrigation infrastructures were brought into light by recent archeological surveys. We scrutinize fast accumulating archeological evidence and review rich historical accounts on late Bronze Age irrigation systems. While the credibility of historical documents is often questioned, with a robust integration with archeological data, they provide important information to understand functions and maintenance of the irrigation projects. We investigate structure and organization of large-scale irrigation systems built and run by states and their importance to understanding dynamic trajectories to social power in late Bronze Age China. Cleverly designed based on local environmental and hydrological conditions, these projects fundamentally changed water management and farming patterns, with dramatic ecological consequences in different states. Special bureaucratic divisions were created and laws were made to further enhance the functioning of these large-scale irrigation systems. We argue that they significantly increased productivity by converting previously unoccupied land into fertile ground and pushed population threshold to a new level. A hypothesis should be tested in further archeological research

    The detector system of the Daya Bay reactor neutrino experiment

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    Predictive value of respiratory symptoms for the diagnosis of pollen-induced seasonal asthma among children and adults in Inner Mongolia

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    Ting Ting Ma,1–3 Yan Zhuang,1 Hai Ying Gong,4 Anthony Chauang Yii,5 Xue Yan Wang,1 Huan Zhong Shi2,3 1Department of Allergy, Beijing Shijitan Hospital, Capital Medical University, 2Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Beijing Institute of Respiratory Medicine, Capital Medical University, 3Center of Medical Research, Beijing Institute of Respiratory Diseases, 4Fangshan District Center for Disease Control and Prevention, Beijing, People’s Republic of China; 5Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore, Singapore Background: The diagnosis of asthma is made on the basis of variable respiratory symptoms and supported by objective evidence of variable airflow limitation. However, spirometry and bronchoprovocation tests may not be routinely available in resource-scarce settings or in the context of large-scale epidemiological studies. There is a gap in knowledge about the predictive value of respiratory symptoms for the diagnosis of pollen-induced asthma.Objective: The aim of this study was to investigate the predictive value of self-reported respiratory symptoms for diagnosing pollen-induced asthma.Patients and methods: We recruited 1,161 patients with respiratory symptoms who presented to the respiratory medicine outpatient clinic of two central hospitals in Inner Mongolia during the pollen season of July–September 2015. All patients were interviewed by a respiratory physician and completed a questionnaire survey, lung function tests and skin prick tests for common inhaled allergens.Results: A total of 392 patients (33.8%) were diagnosed with asthma and 292 (25.2%, 160 adults, 132 children) with pollen-induced asthma. Respiratory symptoms of cough, wheezing, dyspnea, chest pain and nocturnal awakenings due to breathlessness were all associated with increased odds of being diagnosed with pollen-induced asthma, with cough being the most common symptom in both adults and children, giving a sensitivity of 90.6% in adults and 88.6% in children. Wheezing was the most specific symptom (78% and 89.5% in adults and children, respectively) compared to other symptoms. Overall, the positive predictive value of respiratory symptoms was poor for diagnosing pollen-induced asthma, with the exception of wheezing in children which had a high positive predictive value of 72.7%.Conclusion: Cough was the predominant symptom in adults and children with pollen-induced asthma. Wheezing was a reliable predictor of pollen-induced asthma in children. In adults, respiratory symptoms were not sufficiently reliable for diagnosing pollen-induced asthma. Keywords: pollen-induced asthma, asthma symptoms, wheezing, cough, shortness of breat

    Photoluminescence from C+ ion-implanted and electrochemical etched Si layers

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    The microstructural and optical analysis of Si layers emitting blue luminescence at about 431 nm is reported. These structures have been synthesized by C+ ion implantation and high-temperature annealing in hydrogen atmosphere and electrochemical etching sequentially. With the increasing etching time, the intensity of the blue peak increases at first, decreases then and is substituted by a new red peak at 716 nm at last, which shows characteristics of the emission of porous silicon. C=O compounds are induced during C+ implantation and nanometer silicon with embedded structure is formed during annealing, which contributes to the blue emission. The possible mechanism of photoluminescence is presented. (c) 2005 Elsevier B.V. All rights reserved

    A new absorption measurement technique for a capillary super-thin cell

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    We report a new technique of absorption measurement for capillary super-thin cell in the first time. The new technique determines the absorbed intensity instead of the absorbance as conventional way. The absorbed intensity is measured for a capillary cell (i.d. 50 mu m) and a decussate optical super-thin cell (40 mu m) for serial KMnO4 solutions. High sensitivity and good S/N ratio are observed, and the calibration curves are fairy linear. For a 10 mu g/mL KMnO4 solution, the S/N ratio of absorbed intensity determination is about 10, which is better than that of absorbance determination in the capillary cell. This super-thin cell in the decussate configuration provides a novel type optical detection cell for capillary electrophoresis

    Double crystal X-ray diffraction study of MBE self-organized InAs quantum dots

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    A series of GaAs/InAs/GaAs samples were studied by double crystal X-ray diffraction and the X-ray dynamic theory was used to analyze the X-ray diffraction results. As the thickness of InAs layer exceeds 1.7 monolayer, 3-dimensional InAs islands appear. Pendellosung fringes shifted. A multilayer structure model is proposed to describe the strain status in the InAs islands of the sample and a good agreement is obtained between the experimental and theoretical curves
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