255 research outputs found

    Large-Eddy-simulation analysis of airflows and strong wind hazards in urban areas

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    Understanding the characteristics of urban airflows with complex geometrical features is very important from viewpoints of assessing strong wind hazards in the region. This study investigated turbulent airflows and strong wind hazards in an urban area by conducting large-eddy simulations (LESs) with explicit representations of buildings and structures. A business district, including historical architectures, of Kyoto City was chosen. The sensitivity experiments with realistic and idealized building arrangements indicated that the actual, complicated arrangement of buildings as well as the building height variability would enhance an unsteady nature of airflows in urban canopy. An analysis of strong wind hazards under a typhoon condition shows that sustained winds are stronger along streamwise-oriented major streets and over open spaces while instantaneous winds become stronger especially within areas with a mixture of high-rise buildings embedded in low-rise building areas/open spaces. It was indicated that wind gustiness increases with the decrease in building plane-area index. The analysis suggested that both the building height variability and the complex arrangement of buildings are considered to enhance the gustiness of surface winds. This study demonstrated that an LES model is practically useful for assessing the strong wind hazards in urban areas

    体外循環開始後早期にアルカレミア環境で出現する回路内の血液凝集塊形成

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    Purpose : This study investigated the relationship between blood clotting in the circuit soon after initiating cardiopulmonary bypass (CPB) and echinocytes that appear with alkalemia, using a recirculation circuit filled with heparinized bovine blood. Methods : Alkalemic conditions in the recirculation circuit were prepared by adding various concentrations of NaHCO3 to the priming fluid. Albumin was also added to confirm its inhibitory effect on blood clotting. Blood pH, hold-up, the pressure gradient, and red blood cell (RBC) reduction rate were monitored. Blood clots were examined microscopically. Results : Although blood pH was elevated under all experimental conditions, clotting in the circuit increased with increased concentrations of HCO3-. Albumin inhibited the clotting under the same alkalemic conditions. Microscopic findings revealed echinocytes in the blood clots. Conclusions : The shape of echinocytes was transformed by a reduction in the Donnan equilibrium ratio because of changes in pH inside and outside the RBC membrane. Blood clotting in the circuit soon after initiating CPB may be caused by echinocytes that appear under alkalemic conditions. This was inhibited by albumin, suggesting that the addition of albumin to the priming fluid may prevent such clotting in the circuit after initiating CPB.博士(医学)・甲第664号・平成29年3月15日Copyright © 2016 Japanese Journal of Extra-Corporeal Technology(日本体外循環技術医学会)This is a non-final version of an article published in final form in "http://doi.org/10.7130/jject.43.339

    Bayesian Active Questionnaire Design for Cause-of-Death Assignment Using Verbal Autopsies

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    Only about one-third of the deaths worldwide are assigned a medically-certified cause, and understanding the causes of deaths occurring outside of medical facilities is logistically and financially challenging. Verbal autopsy (VA) is a routinely used tool to collect information on cause of death in such settings. VA is a survey-based method where a structured questionnaire is conducted to family members or caregivers of a recently deceased person, and the collected information is used to infer the cause of death. As VA becomes an increasingly routine tool for cause-of-death data collection, the lengthy questionnaire has become a major challenge to the implementation and scale-up of VAs. In this paper, we propose a novel active questionnaire design approach that optimizes the order of the questions dynamically to achieve accurate cause-of-death assignment with the smallest number of questions. We propose a fully Bayesian strategy for adaptive question selection that is compatible with any existing probabilistic cause-of-death assignment methods. We also develop an early stopping criterion that fully accounts for the uncertainty in the model parameters. We also propose a penalized score to account for constraints and preferences of existing question structures. We evaluate the performance of our active designs using both synthetic and real data, demonstrating that the proposed strategy achieves accurate cause-of-death assignment using considerably fewer questions than the traditional static VA survey instruments

    The Role of Seaweed Bed for the Lower Trophic Ecosystem in Coastal Seas

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    藻場は高い基礎生産力を持っており,沿岸海域の低次生態系に対して重要な役割を果たしていると考えられる。本研究では,瀬戸内海の各海域における藻場と水中植物プランクトンとの生産力の比較を行った。水中植物プランクトン生産量に対する藻場生産量の割合は安芸灘で最も高く(10.8%),ついで備讃瀬戸で高い値を示した(3.8%)。一方,広島湾,大阪湾,播磨灘では低い値であった(0.6, 0.3, 0.2%)。季節毎に算出した水中植物プランクトン生産量に対する藻場生産量の割合は冬季に高い割合であった。また,広島湾南部海域を対象海域として,藻場の栄養塩の吸収量・放出量・蓄積量を算出し,栄養塩収支における藻場の役割を定量的に明らかにした。その結果,窒素,リンそれぞれ河川負荷量の14, 40%に相当する量が難分解性有機物として蓄積されていることが明らかになった。Seaweed bed has an important role for the lower trophic ecosystem in coastal seas because of its high primary production. In this study, the primary production of the seaweed bed and the pelagic phytoplankton was compared in each sub area of the Seto Inland Sea. The ratio of the primary production of seaweed bed to pelagic phytoplankton was high at Aki-Nada (10.8 %) and Bisan-Seto (3.8 %), while the ratio was low at Hiroshima-Bay (0.6 %), Osaka-Bay (0.3 %) and Harima-Nada (0.2 %). Seasonally, the ratio was high during winter. The uptake rate by primary production, release rate by decomposition and stock rate as a leaves of nutrients by the seaweed bed were estimated in the southern area of Hiroshima-Bay. The quantitative contribution of seagrass bed to the nutrient budget in this area was estimated. It was estimated that 14 and 40 % of load from the river were accumulated as the less degradable organic matter for nitrogen and phosphorus, respectively

    Treatment of Symptomatic Non-Parasitic Liver Cysts–Surgical Treatment Versus Alcohol Injection Therapy

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    Fourteen patients with benign symptomatic non-parasitic cysts of the liver were either surgically treated, had alcohol injected into the cysts, underwent deroofing of the cyst or in 5, a cystectomy was done. Alcohol was injected into 6 patients and there has been no recurrence for as long as 5 years and 8 months after the treatment. Liver dysfunction occurred in 3 patients given blood transfusion during the surgery and/or postoperative course, an elevated temperature (over 39℃) occurred in one patient. Adverse effects of alcohol injections were minor and transient. Based on our experience, the injection of alcohol is an effective treatment for benign symptomatic cyst of the liver. When a malignancy is suspected on imaging and/or cytologic studies, or when alcohol administration is ineffective, then surgery is indicated

    新生児の睡眠中の心拍変動周波数スペクトルと自律神経活動の関係

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    INTRODUCTION: We analyzed the frequency spectrum of two neonatal sleep stages, namely active sleep and quiet sleep, and the relationship between these sleep stages and autonomic nervous activity in 74 newborns and 16 adults as a comparison. METHOD: Active and quiet sleep were differentiated by electroencephalogram (EEG) patterns, eye movements, and respiratory wave patterns; autonomic activity was analyzed using the RR interval of simultaneously recorded electrocardiogram (ECG) signals. Power values (LFa, absolute low frequency; HFa, absolute high frequency), LFa/HFa ratio, and the values of LFn (normalized low frequency) and HFn (normalized high frequency) were obtained. Synchronicity between the power value of HFa and the LFa/HFa ratio during active and quiet sleep was also examined by a new method of chronological demonstration of the power values of HFa and LFa/HFa. RESULTS: We found that LFa, HFa and the LFa/HFa ratio during active sleep were significantly higher than those during quiet sleep in newborns; in adults, on the other hand, the LFa/HFa ratio during rapid eye movement (REM) sleep, considered as active sleep, was significantly higher than that during non-REM sleep, considered as quiet sleep, and HFa values during REM sleep were significantly lower than those during non-REM sleep. LFn during quiet sleep in newborns was significantly lower than that during active sleep. Conversely, HFn during quiet sleep was significantly higher than that during active sleep. Analysis of the four classes of gestational age groups at birth indicated that autonomic nervous activity in a few preterm newborns did not reach the level seen in full-term newborns. Furthermore, the power value of HFa and the LFa/HFa ratio exhibited reverse synchronicity. CONCLUSION: These results indicate that the autonomic patterns in active and quiet sleep of newborns are different from those in REM and non-REM sleep of adults and may be develop to the autonomic patterns in adults, and that parasympathetic activity is dominant during quiet sleep as compared to active sleep from the results of LFn and HFn in newborns. In addition, in some preterm infants, delayed development of the autonomic nervous system can be determined by classifying the autonomic nervous activity pattern of sleep stages.博士(医学)・乙第1418号・平成30年3月15日© 2017 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved

    Negative correlation between cerebrospinal fluid oxytocin levels and negative symptoms of male patients with schizophrenia

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    Background: Accumulating evidence indicates that oxytocin plays an important role in social interactions. Previous studies also suggest altered oxytocin function in patients with schizophrenia and depression. However, few studies have examined the central oxytocin levels in these disorders. Methods: Cerebrospinal fluid (CSF) oxytocin levels were measured by ELISA in male participants consisting of 27 patients with schizophrenia, 17 with major depressive disorder (MDD), and 21 healthy controls. Results: CSF oxytocin levels of patients with schizophrenia or MDD did not differ significantly with healthy controls. The antidepressant dose or the Hamilton depression rating scale score did not significantly correlate with the oxytocin levels in MDD patients. CSF oxytocin levels in schizophrenic patients significantly negatively correlated with second generation antipsychotic dose (r=-0.49, P=0.010) but not with first generation antipsychotic dose (r=-0.13, P=0.50). A significant correlation was observed between oxytocin levels and negative subscale of PANSS (r=-0.38, P=0.050). This correlation remained significant even after controlling for second generation antipsychotic dose (r=-0.47, P=0.016). Conclusions: We obtained no evidence of altered CSF oxytocin levels in patients with schizophrenia or those with MDD. However, lower oxytocin levels may be related to higher second generation antipsychotic dose and more severe negative symptoms in schizophrenia.ArticleSCHIZOPHRENIA RESEARCH. 139(1-3):201-206 (2012)journal articl
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