著者

黒川 泰嗣 岩橋 眞南実 柳岡 拓磨 和田 恵里佳 長谷川 博

出版者

一般社団法人日本体力医学会

雑誌

体力科学 (ISSN:0039906X)

巻号頁・発行日

vol.71, no.5, pp.389-399, 2022-10-01 (Released:2022-09-13)

参考文献数

50

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The increase in core temperature during exercise in a hot environment causes hyperventilation (hyperthermia-induced hyperventilation), which decreases the partial pressure of arterial blood carbon dioxide. However, the effects on the body of wearing a surgical mask during exercise that would cause hyperthermia-induced hyperventilation have not been clarified. Therefore, we investigated such effects. Ten healthy men participated in the study. A 44-minute steady-state load cycling exercise (55% of peak oxygen uptake) was performed under hot environmental conditions (30℃, 70% relative humidity). Two experimental conditions were set: exercising with surgical face mask (MASK) and without a surgical face mask (CON). The experiment was conducted as a randomized crossover design. Body temperatures, respiratory gas exchange, and subjective indices were measured during exercise. In terms of physiological indices, respiratory rate only revealed a main effect and was significantly lower in the MASK than in CON at 44 min of exercise (CON 41.0±19.2 breaths/min, MASK 35.6±11.2 breaths/min p=0.029). No significant differences were observed between conditions in other physiological parameters. As for the subjective indices, dyspnea showed a condition × time interaction (p=0.016), which was significantly higher in the MASK starting at 5 minutes through the end (CON 4.5±3.5 and MASK 8.5±2.1 at the end of exercise p=0.016). No significant differences were observed in other subjective measures. In conclusion, wearing a surgical face mask during moderate-intensity prolonged exercise under hot environmental conditions significantly worsened dyspnea, but no significant differences were observed in other physiological indices or subjective indices.

著者

黒川 泰嗣 岩橋 眞南実 柳岡 拓磨 長谷川 博

出版者

一般社団法人日本体力医学会

雑誌

体力科学 (ISSN:0039906X)

巻号頁・発行日

vol.71, no.2, pp.193-203, 2022-04-01 (Released:2022-03-14)

参考文献数

41

被引用文献数

1

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Prolonged exercise in a hot environment increases the minute ventilation (VE) and respiratory rate (RR) with an increase in core temperature. This hyperthermia-induced hyperventilation decreases the partial pressure of arterial blood carbon dioxide (PaCO2). Conversely, nasal breathing during exercise has been reported to produce low VE and RR values and high PaCO2 values; however, no studies have investigated this in hot environments. Therefore, the purpose of this study was to clarify the effect of nasal breathing on estimated partial pressure of carbon dioxide in arterial blood (PaCO2,estimate) during prolonged exercise in a hot environment. Twelve university endurance athletes participated in the study and performed a 40-minutes steady-state cycling exercise at an intensity of 55% of peak oxygen uptake in a hot environment (room temperature 35℃, relative humidity 40%). Using randomized crossover design, two experiments were performed—nasal breathing condition (NB) and mouth breathing condition (MB). Moreover, physiological indices were measured during the exercise. Rectal temperature increased in both conditions, but there was no significant difference between these conditions. PaCO2,estimate values were significantly higher in NB between 10 minutes and 40 minutes of exercise (p < 0.05) compared to MB, and decreased with time in MB. Compared to MB, the VE was significantly lower in NB between 30 minutes and 40 minutes (p < 0.05), while the RR was significantly lower in NB between 25 minutes and 40 minutes of exercise (p < 0.05). Therefore, nasal breathing during a prolonged moderate-intensity exercise in a hot environment prevented the decrease in PaCO2,estimate due to hyperthermia-induced hyperventilation.

著者

西田 良平 黒川 泰 赤木 三郎

出版者

鳥取大学教養部

雑誌

鳥取大学教養部紀要 (ISSN:02874121)

巻号頁・発行日

no.27, pp.p187-226, 1993-11

著者

黒川 泰亨 中村 健二郎

出版者

公益社団法人日本オペレーションズ・リサーチ学会

雑誌

Journal of the Operations Research Society of Japan (ISSN:04534514)

巻号頁・発行日

vol.20, no.4, pp.259-272, 1977-12

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The forest production greatly relies on nature and variations of the natural conditions related to the production are not small. Then, because of the long production time span, it is necessary to concider the forest management planning as a planning under uncertainty. The purpose of this paper is to present a forest management planning by coordinating the uncertainty and the efficiency of forest production. The theory of stochastic programming is applied. The forest management planning consists of two phases: One is long term and the other is short term. This paper is concerned with the long term planning such as from 60 to 80 years. This planning is how to derive the present forest condition to the objective forest condition and this is one of the most basic requirements in forest management planning. In this paper, the objective forest stand condition is the normal age-class arrangement. A planning method applied here is to minimize the variance of forest yield volume under the condition of keeping its expectation arbitrarily fixed, and the other planning method adopts one of the von Neumann-Morgenstern utility functions. They are formulated as a quadratic programming problem. The methods are applied to a real forest management planning and the unique optimal plan is provided for this case. Our models will be significant in the planning at the divisional forest-office in the national forest.

著者

黒川 泰亨

出版者

鳥取大学

雑誌

鳥取大学農学部研究報告 (ISSN:03720349)

巻号頁・発行日

vol.55, pp.5-12, 2002-11

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林木の成長に関する幾つかの経験的知識にもとづいて林分密度の変化や生育期間の経過に伴って林木の成長現象を記述するシステムを成長モデルというが、本稿では、異齢林を対象としたJ.ボンジョルノによる林分成長モデルを使用して、異齢林に関する収穫予定の最適計画策定に関して若干の基礎的考察を加えた。手法的には林分成長モデルと線形計画法による最適化問題との融合であり、異齢林に関する最適収穫の決定問題である。なお次のような問題を残しているが、これらのことは次の研究課題としたい。1)最適計画の策定における目的を収穫量の最大化としたが、割引純利益の最大化を目的とした計画に関する検討、2)回帰年を5年として固定したが、これを変更する場合の検討〔3〕、3)林分成長モデルにおける直径階を6~7程度に増やすことの検討、4)線形計画における感度分析およびジャドウプライスの検討等である。

著者

井川 房夫 日高 敏和 黒川 泰玄 米澤 潮 小林 祥泰

出版者

一般社団法人 日本脳卒中の外科学会

雑誌

脳卒中の外科 (ISSN:09145508)

巻号頁・発行日

vol.43, no.4, pp.262-266, 2015 (Released:2015-09-29)

参考文献数

15

被引用文献数

5 4

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The incidences of subarachnoid hemorrhage (SAH) in Finland and Japan are the highest in the world, with about 20-23 cases per 100,000 persons per year. Since the report of the International Subarachnoid Aneurysm Trial (ISAT) was published, the use of intravascular coil embolization (CE) for cerebral aneurysm has become more frequent worldwide. In this paper, we discuss the current situation of therapy for cerebral aneurysm in Japan according to the data of our institute, the Japan Standard Stroke Registry Study, and the Japan Neurosurgical Society.From 1999 to 2013, 543 cases of ruptured saccular cerebral aneurysms were treated in Shimane Prefectural Central Hospital. According to data, most cases occurred in men in their fifties and in women in their seventies. The mean sizes of ruptured cerebral aneurysm according to site were 7.4 ± 4.1, 7.0 ± 5.4, and 5.5 ± 2.5 mm in the internal carotid artery posterior communicating artery, middle cerebral artery, and anterior communicating artery, respectively. Aneurysms smaller than 5 mm account for 187 (34.4%) of the cases.According to the Japan Standard Stroke Registry Study, the poor outcome rates (modified Rankin scale score, 3-6) according to the ISAT criteria were 18.3% and 24.2% in the surgical clipping (SC) and CE groups, respectively. These rates were superior to the ISAT data (36.4% for SC and 25.4% for EC). According to the survey of the Japan Neurosurgical Society from 2001 to 2011, the prevalence of cerebral aneurysm cases treated with clipping decreased from 88.2% in 2001 to 71.2% in 2011. The number of ruptured cerebral aneurysms treated with clipping also decreased. However, the frequency of clipping for unruptured cerebral aneurysm was increasing.

著者

井上 昭夫 黒川 泰亨

出版者

日本林學會

雑誌

日本林學會誌 = Journal of the Japanese Forestry Society (ISSN:0021485X)

巻号頁・発行日

vol.83, no.2, pp.130-134, 2001-05-16

参考文献数

19

被引用文献数

3

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針葉樹における二変数材積式を理論的に誘導した。相対幹曲線式としてKunze式を採用した。既存の研究成果に基づいて, 相対高0.7と0.5における正形数&lambda;<SUB>0.7</SUB>と&lambda;<SUB>0.5</SUB>は, それぞれ0.7と1.0で安定していると仮定した。これらの仮定より, 相対幹曲線式の係数を推定する二つの方法を誘導した。これらの方法によって推定される係数は, 互いに等しいと仮定した。その結果, 次の二変数材積式が得られた;v=&pi;d<SUB>b</SUB><SUP>2</SUP>h/4{2(1-h<SUB>b</SUB>/h)}<SUP>1.060</SUP>。ここで, vは幹材積, d<SUB>b</SUB>は胸高直径, hは樹高, h<SUB>b</SUB>は胸高 (=1.2m) である。この材積式をスギとヒノキの資料に適用した。推定された幹材積の標準誤差はスギで0.028m<SUP>3</SUP>, ヒノキで0.025m<SUP>3</SUP>であった。誘導した材積式の仮定と関数形に基づいて, この材積式の特徴について考察した。

著者

黒川泰男 小山内洸 早川勇共著

出版者

三友社出版

巻号頁・発行日

1985

著者

黒川泰男著

出版者

三友社出版

巻号頁・発行日

1986

著者

黒川 泰貴 西村 昭徳 石村 郁夫

出版者

東京成徳大学

雑誌

東京成徳大学臨床心理学研究

巻号頁・発行日

vol.10, pp.3-15, 2010-03