动机过程对青少年网络游戏行为意向的影响模型

从行为动机的角度探讨影响青少年网络游戏玩家游戏意向的主要因素。通过对北京市中学生进行抽样调查并采用结构方程模型的方法对模型进行检验。结果显示,青少年网络游戏玩家的游戏意向受多种内在动机和外在动机共同影响。青少年玩网络游戏的基本内在动机（如,社会交际、超越现实、自我效能和享受乐趣）促进沉浸动机的形成。同时,沉浸是提高游戏意向的内在动机,主观规范和游戏涉入度是分别降低和提高游戏意向的外在动机。此外,内部动机和外部动机对游戏意向的影响存在交互作用     

The relation of hypertension to cognitive function

Hypertension is an established risk factor for stroke. However, prior to such a major clinical event, hypertension exerts a more subtle impact on the brain that is revealed by diminished cognitive function. Studies comparing the performance of people with high and normal blood pressure levels have shown that high blood pressure or hypertension is related to poorer performance on tests of attention, learning and memory, executive functions, visuospatial skills, psychomotor abilities, and perceptual skills. Hypertension is also predictive of cognitive decline. Variables that may alter (i.e., moderate) the relation of hypertension to cognitive function include age, education, several biological characteristics of hypertension, and the presence of concurrent diseases. Although hypertensives are not clinically impaired, their diminished levels of cognitive performance could affect their perceived quality of life. Various brain mechanisms may explain the relation of hypertension to lower levels of cognitive function. Further understanding of the relation between hypertension and cognition is critical to the preservation of cognitive function across the life span.     

Are pets a healthy pleasure? the influence of pets on blood pressure

Pet owners often describe their pets as important and cherished family members who offer solace in times of stress. This article considers evidence suggesting that pets influence human blood pressure. Studies on this topic extend current research testing the hypothesis that having other people around in stressful times can buffer the negative consequences of stress. The existing data suggest that people perceive pets as important, supportive parts of their lives and that the presence of a pet is associated with significant cardiovascular benefits, among both people with normal blood pressure and those with high blood pressure. Studies about pets and blood pressure have examined both naturally occurring and randomly assigned pet ownership but are limited by their focus on responses to short-term, acute stress. Future prospective studies should explore the influence of pets on people at risk for cardiovascular disease and also consider explanatory mechanisms for the pet effect.     

基于绿色供应链原理的输血管理研究

通过对绿色供应链管理和输血管理概念的比较,将"绿色供应链"理念融入到了输血管理中,并类比绿色供应链模型,提出了输血管理物流、信息流模型,系统总结了输血管理的体系结构,并进一步对输血管理实施的途径和管理中应注意的问题提出了看法.     

胰岛素抵抗与2型糖尿病关系的新思考

胰岛素抵抗(IR)与2型糖尿病关系密切,对IR的认识,经历了几十年反复的过程,胰岛素抵抗综合征(IRS)的提出使2型糖尿病防治观念发生了根本的转变,提出了2型糖尿病防治新策略:从以降糖治疗为主到全面防治心血管疾病.对IR的认识和IR与2型糖尿病的关系,体现了辩证唯物主义认识论和系统论的观点.     

Evaluation of pre-operative anxiety and propofol-induced sedation using newly proposed indices of finger vascular tone

Abstract: This study examined estimates of finger vascular tone, obtained from photoplethysmography. Normalized and double‐normalized pulse volume (NPV and DNPV), blood volume (BV), and pulse volume (PV) were obtained in 2 male and 7 female middle‐aged patients at an outpatient office 1–3 days before an operation and in the operating room before and after anesthesia by propofol. There was a preoperative decrease in NPV, and the propofol injection yielded a moderate increase in BV. The latter seemed to contribute to a decrease in DNPV. A partial correlation controlling for body mass index was observed between the change in NPV and the dose of propofol; a larger reduction in NPV before anesthesia compared with the control condition was accompanied by the need for a greater infusion of propofol for sedation. In conclusion, among the measures examined, NPV appears to be the best indicator of heightened arteriolar vascular tone.     

CHANGES IN BLOOD PRESSURE AND HEART RATE DURING FIXED‐INTERVAL RESPONDING IN SQUIRREL MONKEYS

Episodic and sustained increases in heart rate and mean arterial blood pressure can occur with recurring patterns of schedule‐controlled behavior. Most previous studies were conducted under fixed‐ratio schedules, which maintained a consistent high rate of responding that alternated with periods of no responding during times when the schedule was not in operation. The present study examined changes in heart rate and blood pressure under fixed‐interval schedules which maintained a range of rates that varied from little or no responding at the beginning of the fixed interval to high rates at the end of the interval. The relations of cardiovascular function to rate of responding were examined. Squirrel monkeys prepared with arterial catheters were trained to respond under fixed‐interval schedules of electric‐shock presentation. The duration of the interval was varied across sessions and cardiovascular parameters were examined. Local rates of responding were typically near zero during timeout periods, low at the beginning of each fixed‐interval cycle, and then increased as the fixed interval progressed. At most schedule durations, arterial blood pressure and heart rate levels were lowest at the beginning of the interval cycles, increased as the rate of responding increased, and then decreased during the timeout periods. At all parameters studied, there was a direct relationship between changes in response rate within fixed‐interval cycles and changes in heart rate and blood pressure. The results suggest that a much closer concordance of these cardiovascular parameters and schedule‐controlled responding is obtained by examining ongoing behavior as it occurs within the contingencies by which it is maintained.     

The global non-entropic arrow of time: from global geometrical asymmetry to local energy flow

Since the nineteenth century, the problem of the arrow of time has been traditionally analyzed in terms of entropy by relating the direction past-to-future to the gradient of the entropy function of the universe. In this paper, we reject this traditional perspective and argue for a global and non-entropic approach to the problem, according to which the arrow of time can be defined in terms of the geometrical properties of spacetime. In particular, we show how the global non-entropic arrow can be transferred to the local level, where it takes the form of a non-spacelike local energy flow that provides the criterion for breaking the symmetry resulting from time-reversal invariant local laws.     

Behavior analysis and the search for the origins of hypertension.

Hypertension is a disorder of sodium regulation that develops over time in a context of the interactions of the individual with the environment. Experimental hypertension can be induced in laboratory animals and normotensive humans via increases in sodium intake under conditions of aversive behavioral control. Readiness for avoidance contingencies includes a breathing pattern characterized by subnormal rate and normal tidal volume. Studies with humans have shown that this inhibitory breathing pattern is associated with increased plasma acidity, increased renal sodium reabsorption, increased secretion of digitalis-like hormones that inhibit sodium-pump activity, and increased vasoconstriction and blood pressure. Behavioral research is needed that defines the necessary and sufficient conditions for inhibitory breathing and its role in the development of hypertension.     

Stability of visceral behavior in the awake rat during rest.

Brady and colleagues have championed the importance of careful delineation and control of a subject's behavioral state. In this paper we develop the concept of visceral behavior from a physiological perspective. Sprague-Dawley rats were instrumented to record arterial blood pressure, renal sympathetic nerve activity, and respiration. The rats were restrained in a conical cloth sock. Rats that were well adapted to the sock restraint showed a regular respiratory pattern and consistent pressure recordings; they rested quietly in the sock and moved only occasionally to adjust their position. Fourier analysis of blood pressure and nerve activity showed a concentration of power below 1 Hz. The coherence between the two signals was strong (0.83 +/- 0.03) at 0.42 Hz. Conversely, during their initial adjustment to the sock restraint, the rats tended to show large fluctuations in blood pressure associated with episodic apneic breathing; 1 animal displayed this pattern of visceral behavior throughout most of the experiment. Despite this instability in pressure, the rats' overt behavior was stable: They rested quietly in the sock with only occasional position shifts. Spectral analysis and coherence computations showed large shifts in the distribution of power and frequency range over which arterial pressure and sympathetic activity were tightly coupled. These data are consistent with the view that an animal's circulatory adjustments, as well as adjustments in other aspects of its physiological state, constitute an important aspect of behavior, and that this behavior can influence the interpretation of biobehavioral data.