Issues in Student Surveys of a Permanent Experimental Stand in a Research Forest

学生実習による固定試験地調査を通じて，授業でのフィールド調査の割り当て方法について検討した。信州大学農学部手良沢山演習林のイチイ植林地において，参加学生20名を4班に分け，先回り探索（他の班との位置関係と未調査木の位置をもとに次の調査木を選ばせる方式）で，立木のサイズと位置の計測を実施した。全体では94本（班ごとに17～28本）の立木が調査され，胸高直径（DBH）は正規分布し，班ごとに見ても平均DBHに有意差はなく概ね正規分布していた。立木の位置情報をもとに調査中の各班の移動の軌跡を描いたところ，調査終了まで開始時点の各班の位置関係がほぼ保たれ，軌跡が互いに交錯することはなかった。また，班ごとで調査終了までの時間差はほとんど生じなかった。次の調査木への距離（平均の水平距離3.0～3.5m，垂直距離1.0～1.8m）に班ごとに有意差はなく，調査条件に班ごとの著しい違いはなかった。また，最も調査本数の多かった班で，標識番号の誤記入が1件見られ，それによって欠測と重複カウントをそれぞれ1本ずつ生じたのと等しい状況になった。各班の意思に任せる先回り方式での調査割り当てでは，班ごとの能率に合わせて調査地が分担されることが確かめられたが，問題点として調査ミスを検出しにくいことが挙げられた。Article環境科学年報 40:57-63(2018)research repor

National trends in the outcomes of subarachnoid haemorrhage and the prognostic influence of stroke centre capability in Japan: retrospective cohort study

Objectives To examine the national, 6-year trends in in-hospital clinical outcomes of patients with subarachnoid haemorrhage (SAH) who underwent clipping or coiling and the prognostic influence of temporal trends in the Comprehensive Stroke Center (CSC) capabilities on patient outcomes in Japan.Design Retrospective study.Setting Six hundred and thirty-one primary care institutions in Japan.Participants Forty-five thousand and eleven patients with SAH who were urgently hospitalised, identified using the J-ASPECT Diagnosis Procedure Combination database.Primary and secondary outcome measures Annual number of patients with SAH who remained untreated, or who received clipping or coiling, in-hospital mortality and poor functional outcomes (modified Rankin Scale: 3–6) at discharge. Each CSC was assessed using a validated scoring system (CSC score: 1–25 points).Results In the overall cohort, in-hospital mortality decreased (year for trend, OR (95% CI): 0.97 (0.96 to 0.99)), while the proportion of poor functional outcomes remained unchanged (1.00 (0.98 to 1.02)). The proportion of patients who underwent clipping gradually decreased from 46.6% to 38.5%, while that of those who received coiling and those left untreated gradually increased from 16.9% to 22.6% and 35.4% to 38%, respectively. In-hospital mortality of coiled (0.94 (0.89 to 0.98)) and untreated (0.93 (0.90 to 0.96)) patients decreased, whereas that of clipped patients remained stable. CSC score improvement was associated with increased use of coiling (per 1-point increase, 1.14 (1.08 to 1.20)) but not with short-term patient outcomes regardless of treatment modality.Conclusions The 6-year trends indicated lower in-hospital mortality for patients with SAH (attributable to better outcomes), increased use of coiling and multidisciplinary care for untreated patients. Further increasing CSC capabilities may improve overall outcomes, mainly by increasing the use of coiling. Additional studies are necessary to determine the effect of confounders such as aneurysm complexity on outcomes of clipped patients in the modern endovascular era