273 research outputs found

    Evaluation of an economic model composed of producer agents

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    In recent years, the existence of a "social divide", comprising factors such as income and professional status, has been noted as one significant type of social issue. It has been stated that, among the disparate groups, a member belonging to one group cannot move to any other groups. Such a rigidity in terms of social status results in non-activation of the economy. In this study, we have suggested a dynamic economic model described by a multi-agent system, and have evaluated its dynamics in order to try to understand the mechanisms by which how the social divide emerges within the model. We used Gini's coefficient to evaluate the social divide and its economic efficiency. As a result, it is suggested that economies under conditions of low competitiveness, being a state composed of relatively more consumer agents than producer agents, display a higher negative relationship between Gini's coefficient and economic efficiency than those under conditions of high competitiveness

    Neotenic reproductives influence worker caste differentiation in the termite Reticulitermes speratus (Isoptera; Rhinotermitidae)

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    Division of labor among castes in social insect colonies increases ergonomic efficiency and colony-level fitness, and has played a key role in the ecological success of social insects. Knowledge of the factors that regulate castes is important for understanding adaptive social organization. Our previous study on the termite Reticulitermes speratus demonstrated that the presence of a pair of nymphoid reproductives during development affected offspring caste ratios. In the present study, we investigated further the influence of individual neotenics on offspring caste ratios. Parthenogenetically-produced offspring were reared in worker-tended experimental colonies with the addition of different forms (nymphoid or ergatoid) and numbers of neotenics, and compared the caste ratios of the offspring between the different experimental treatments. We found that all offspring in worker-only tended colonies became nymphs, while a proportion of offspring in colonies with a single neotenic (with the exception of male ergatoids) differentiated into workers. These results show offspring caste ratios are influenced by the presence of single female ergatoids, single female and male nymphoids, while they remain unaffected by the presence of male ergatoids

    体外肺切除術に関する実験的研究

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    金沢大学医学部附属病院【目的】肺癌に対する体外肺切除術の安全性を確立し,臨床でも合併症なく施行できる術式とすることを目的として実験を施行した。【研究方法】雑種成犬を用い,肺癌に対する体外肺切除モデルを作成した。実験動物を全身麻酔の後,左主肺動脈,肺静脈の中枢側を鉗子で遮断し切離後,左主気管支を切断し左肺を摘出する。摘出した左肺をEuro-Collins液で灌流し,体外で後葉を前葉から分離し1時間保存する。この間,縦隔リンパ節を周囲の脂肪組織を含め充分に郭清する。次いで,後葉を上肺静脈,主気管支,主肺動脈の順に吻合し自己肺移植を完了する。この実験系に対し次の3群を作成した。1群,気管支吻合部の被覆なし;2群,気管支吻合部を有茎肋間筋で被覆;3群,気管支吻合部を有茎大網で被覆。各群に対して以下の項目を測定した。1.経時的に気管支ファイバースコープにて吻合部を観察し,レーザー血流計にて気管支粘膜の組織血流量を経時的に測定する。2.術中,術後の肺表面組織血流量,動脈血ガス分析等を施行する。3.経時的に胸部X線写真を撮影する。4.犠牲屠殺し,気管支・血管の吻合部,移植肺,健側肺の病理組織を検討する。4.各群の生存日数の比較。【結果】1.肺表面組織血流は肺移植直後では開胸時と比べて各群ともに80%前後と良好であった。開胸時,移植直後のPaO_2,PaCO_2も各群ともに良好であった。2.各群の成績では1群では6頭中5頭が3〜26日以内に死亡した。死因は出血1例,気管支吻合部縫合不全3例,肺炎1例であった。2群では4頭中1頭のみ30日以内に死亡(気管支吻合部縫合不全)した。3群では5例中2頭が30日以内に死亡したが,気管支吻合部縫合不全によるものはなく,衰弱,肺炎によるものであった。3.経時的な気管支ファイバースコープ,胸部X線写真ともに合併症のない群では良好な所見を呈した。気管支粘膜の組織血流量は2群,3群は1群に比べ特に術後7日以内で良好であった。【まとめおよび今後の課題】肺癌に対する体外肺切除術施行時の気管支吻合部合併症予防に有茎肋間筋被覆,有茎大網被覆は有用と考えられたが,今後症例数を増やしてさらに検討していく必要がある。研究課題/領域番号:08671519, 研究期間(年度):1996出典:研究課題「体外肺切除術に関する実験的研究」課題番号08671519(KAKEN:科学研究費助成事業データベース(国立情報学研究所)) (https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-08671519/)を加工して作

    原発性非小細胞肺癌切除例における核DNA量に関する基礎的ならびに臨床的研究

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    取得学位 : 博士(医学), 学位授与番号 : 医博甲第971号, 学位授与年月日:平成3年3月25日,学位授与年:199

    Preoperative Diagnosis of Adult Intussusception Caused by Small Bowel Lipoma

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    Adult intussusception is rare, accounting for only 5% of all intussusceptions, for which preoperative diagnosis is difficult. We herein report a preoperatively diagnosed case of adult intussusception caused by a small bowel lipoma. A 33-year-old man was admitted to our hospital with three weeks history of colicky epigastric pain. Computed tomography revealed thickening of the ileal wall suggestive of intussusception. Colonoscopy revealed an ileocolic intussusception. Barium enema for reduction of ileocolic intussusception demonstrated a small bowel tumor in the ileum 15 cm proximal to the ileocecal valve. The intussusception was reduced, and the patient underwent partial resection of the ileum encompassing the small bowel tumor. Histological findings confirmed the diagnosis of lipoma of the small bowel. The patient made a satisfactory recovery and remains well

    Neuropathic Bladder Caused by Caudal Regression Syndrome without Any Other Neurogenic Symptoms

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    Caudal regression syndrome (CRS) is a rare congenital vertebral anomaly, which occurs most often in combination with spinal cord malformations and morphologic dysfunctions of the lower extremities; these signs are useful for both patients and clinicians in the diagnosis of this syndrome. However, in certain cases, clinicians have failed to identify the syndrome due to the lack of apparent anomalies, resulting in the progression of renal dysfunction caused by neuropathic bladder when CRS is eventually identified. Here, we report a case of a 2-year-old girl who was referred to our hospital for vesicoureteral reflux. At examination, she presented no neurological symptoms; however, on cystourethrography and CT scanning we found that the sacral bone was absent, through which CRS was diagnosed. A urodynamic study indicated detrusor-sphincter dyssynergia, and clean intermittent catheterization was initiated. In the present report, we describe a case of CRS with no neurologic symptoms other than a neuropathic bladder. The lack of outward signs can result in delayed diagnosis. Thus, urological examinations, including a urodynamic study, might be the only clue for identifying an underlying neurologic injury involving the lower spinal cord
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