Prior distributions on symmetric groups

Fully and partially ranked data arise in a variety of contexts. From a Bayesian perspective, attention has focused on distance-based models; in particular, the Mallows model and extensions thereof. In this paper, a class of prior distributions, the Binary Tree, is developed on the symmetric group. The attractive features of the class are: it provides a closed-form solution to the posterior distribution; and a simple way to interpret the parameters of the prior distribution. The advantages of the proposed method are illustrated by comparing it to metric-based models using data analyzed by other researchers in this context.This revised article was published online in August 2005 with the PDF paginated correctly.     

The role of contingencies and "principles of behavioral variation" in pigeons' pecking

Staddon and Simmelhag's proposal that behavior is produced by “principles of behavioral variation” instead of contingencies of reinforcement was tested in two experiments. In the first experiment pigeons were exposed to either a fixed-interval schedule of response-contingent reinforcement, an autoshaping schedule of stimulus-contingent reinforcement, or a fixed-time schedule of noncontingent reinforcement. Pigeons exposed to contingent reinforcement came to peck more rapidly than those exposed to noncontingent reinforcement. Staddon and Simmelhag's “principles of behavioral variation” included the proposal that patterns (interim and terminal) were a function of momentary probability of reinforcement. In the second experiment pigeons were exposed to either a fixed-time or a random-time schedule of noncontingent reinforcement. Pecking showed a constant frequency of occurrence over postfood time on the random-time schedule. Most behavior showed patterns on the fixed-time schedule that differed in overall shape (i.e., interim versus terminal) from those shown on the random-time schedule. It was concluded that both the momentary probability of reinforcement and postfood time can affect patterning.     

镇静与镇痛在ICU机械通气患者中的应用变化

探讨ICU内机械通气患者应用镇痛剂、镇静剂及肌松剂的情况及其对机械通气和预后的影响。回顾性分析我院中心ICU2006年、2007年收治的244例行有创机械通气治疗超过48h患者的临床资料,并将患者分为2006年组和2007年纽,用统计软件分析患者在年龄、性别、入ICU时APACHEⅡ评分、血糖、血浆白蛋白、基础疾病,气管插管时间、机械通气时间、ICU住院天数、镇痛与镇静剂应用的时间、机械通气时是否使用肌松剂、Ramsay评分及病死率方面是否存在差别。统计分析显示2006年组和2007年组在年龄、性剐、入ICU时APACHEⅡ评分、血糖、血浆白蛋白、是否使用肌松剂及基础疾病方面无差别;与2006年组相比2007年组患者气管插管时间、机械通气时间及ICU住院天数均缩短,镇痛与镇静剂应用时间均缩短,Ramsay评分降低,病死率下降。提示对机械通气的危重症患者应合理使用镇痛剂与镇静剂。     

Behavioral adaptation to fixed-interval and fixed-time food delivery in golden hamsters

Food-deprived golden hamsters in a large enclosure received food every 30 sec contingent on lever pressing, or free while their behavior was continuously recorded in terms of an exhaustive classification of motor patterns. As with other species in other situations, behavior became organized into two main classes. One (terminal behaviors) increased in probability throughout interfood intervals; the other (interim behaviors) peaked earlier in interfood intervals. Which class an activity belonged to was independent of whether food was contingent on lever pressing. When food was omitted on some of the intervals (thwarting), the terminal activities began sooner in the next interval, and different interim activities changed in different ways. The interim activities did not appear to be schedule-induced in the usual sense. Rather, the hamsters left the area of the feeder when food was not due and engaged in activities they would normally perform in the experimental environment.     

胰腺癌综合治疗面面观

在胰腺癌的综合治疗中,手术切除是清除肿瘤负荷的最有效的局部治疗方法,但其效果会受到胰腺癌恶性行为和解剖位置的限制.从“重视全面、避免关注片面”的哲学高度,科学看待手术和其他综合治疗手段的关系和意义,有助于对胰腺癌的综合治疗有一个正确的理解,也有助于临床治疗措施的制定.本文首先对胰腺癌治疗过程的若干问题进行再思考,在此基础上再认识胰腺癌的综合治疗,最后对胰腺癌诊治发展进行展望,以期有一个相对全面的解读.     

ICU患者的浅镇静：我们追求的目标？

镇静治疗是ICU综合治疗的重要组成部分。随着ICU的发展,先后颁布了3个有关ICU患者的镇静指南,镇静治疗的理念也逐渐发生改变。2013年美国重症医学会颁布的ICU成人患者疼痛、躁动、谵妄治疗指南推荐的镇静目标为浅镇静。该指南是以大量临床研究结论为基础提出的,更具有广泛代表性和推广价值。本文从浅镇静的理论基础、具体实施方案、镇静深度的监测、镇静药物的选择以及浅镇静的局限性等方面具体阐述ICU患者浅镇静策略的相关问题,以期ICU同道能更好地理解和临床实施ICU成人患者的浅镇静策略。     

咪达唑仑—舒芬太尼靶控输注辅助神经阻滞用于颈部手术临床观察

观察咪达唑仑复合舒芬太尼TCI及恒速输注辅助颈丛阻滞颈部手术的镇痛镇静效果及对术中知晓、血液动力学和呼吸的影响,将80例择期颈部手术患者,随机分为2组各40例：咪达唑仑复合舒芬太尼TCI组（A组）;咪达唑仑复合舒芬太尼恒速输注组（B组）。比较二组MAP,HR,RR,SpO2等及术中镇痛、镇静、术中知晓和各种不良反应发生情况。发现A组血液动力学较B组更加稳定。提示TCI辅助颈丛阻滞麻醉安全有效,镇痛良好,无术中知晓,较恒速输注血液动力学更稳定,呼吸抑制少。     

Ego development in the face of death: How being HIV positive affects movement through Erikson's adult stages of development

Erikson's epigenetic model of psychosocial development posits that each of eight stages unfolds in a particular sequence, and each becomes the primary issue of concern at specified times in the life cycle. Erikson does not address, nor could any empirical studies be located, exploring how the emergence of these eight stages might be affected by a diagnosis of terminal illness. The purpose of this study was to understand how an HIV-positive diagnosis affected movement through Erikson's stages of development. In-depth interviews were conducted with a sample of 18 HIV-positive men and women under 45 years of age. Analysis of the qualitative data revealed three findings regarding Erikson's stages: (1) The fifth stage of idenitity versus role confusion was revisted and the sense of self is redefined; (2) the three adulthood stages of intimacy versus isolation, generativity versus stagnation, and ego integrity versus depair were dealt with simulataneously and, in most cases, resolved favorably; and (3) intimacy and generativity enabled and supported the resolution of the tasks of identity and ego integrity.