飞行人员梅尼埃病的特点

目的探讨飞行人员梅尼埃病的特点及对航空航天飞行的影响。方法总结飞行人员梅尼埃病资料２２份。结果２２例表典型的眩晕发作,２１例耳鸣,１９例有听力下降,１１例前庭功能异常,结论梅尼埃病可能危及航空航天安全,航空航天可能加重梅尼埃病的内耳损害。     

空勤人员神经行为功能核心测试特点的实验研究

目的：分析空勤人员、侦听人员、指挥专业研究生神经行为功能的特点，为选拔和培养优秀空勤人材提供依据，为下一步选拔航天方面的专业人材提供方法学上的借鉴。方法：对3组82名被试者进行世界卫生组织（WHO）神经行为功能测试组合（NCTB）测试，并对其结果进行分析及组与组之间的比较。结果：空勤人员在神经行为功能方面较侦听专业、指挥专业研究生有明显优势，其中较侦听专业优势指标6项，劣势3项；较指挥专业研究生优势指标3项，劣势2项。结论：空勤人员在神经行为功能方面是这3类人群中的优秀者，指挥专业研究生组次之，侦听专业较差。WHO NCTB是一种从神经行为功能方面选择人材的理想方法。     

茶多酚对飞行人员微循环及抗氧化能力的影响

目的研究茶多酚对飞行人员球结膜微循环（ＢＣＭ）的影响及抗氧化作用,为飞行人员选择合适的抗氧化保健药品。方法４０名健康疗养飞行人员随机分为ＴＰ组,对照组（服安慰剂）,２０ｄ后检测。结果ＴＰ组红细胞超氧化物岐化酶（ＳＯＤ）活性,全血谷光甘肽过氧化物酶（ＧＳＨ－ＰＸ）活性及血清丙二醛（ＭＤＡ）含幽会明显高于对照组,ＭＤＡ明显低于对照组。ＴＰ组ＢＣＭ微血管数明显增加;微血流速度明显加快;轻中度红细胞聚集明     

飞行人员变应性鼻炎的特点及对飞行的影响

目的 探讨变应性鼻炎和航空航天飞行的关系。方法 总结分析飞行人员变应性鼻炎资料３２份。结果 ３２例中常年性鼻炎２０人,季节性变应性鼻炎１２人。２６例继续飞行,６例永久停飞。结论 变应性鼻炎可影响航空航天飞行;航空航天飞行也可诱发或加重变应性鼻炎。     

Aircrew helmet protection against potential cerebral concussion in low-magnitude impacts.

The response of the Gentex DH-151 (contact type) and Gentex 411 (suspension type) aircrew helmets to low-magnitude impacts, such as those sometimes encountered during cockpit buffeting, in ejection, and in parachute landings, was studied to augment the data base on helmet performance. The helmets, mounted on a Hodgson headform, were dropped on the crown and rear at impact velocities up to 4.97 m/s. Acceleration time histories were tape recorded and digitized and Gadd Severity Indices (GSI), among others, were calculated from the resultant acceleration curve. Both helmets kept the GSI below predicted concussion thresholds at 4.97 m/s and were considered to perform well on initial impacts. On second impacts, the GSI rose considerably because the shell and liner of the DH-151 cracked and the suspension of the "141" stretched during the first blow. Improvement of the multiple impact performance of both helmets appears desirable, although the suspension helmet performed slightly better than the contact helmet with respect to the criterion used.     

Aircrew medical standards and their application in the Royal Australian Air Force.

Aircrew selection and health maintenance are key factors in the Aviation Medicine Program of the Royal Australian Air Force. The physical standards employed by the RAAF in selecting aircrew are reviewed. The aircrew selection process for the 5 years 1969 to 1973 are presented with emphasis given to medical causes for rejection. A careful analysis of reasons for failure to complete aircrew training was conducted. The results of this analysis are presented with special emphasis being given to medical wastage. The process of medical evaluation of trained aircrew is discussed along with the 1969-1973 experience with aircrew duty restrictions and waivers granted for medical conditions. The RAAF experience with medical wastage of trained aircrew is similar to the experience of other nations, both as to wastage rates and body systems involved.     

ApoE基因多态性及累计飞行时间与飞行人员血脂水平关系的研究

目的 研究ApoE基因多态性及累计飞行时间对飞行人员血脂水平的影响.方法 以聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)法测定ApoE基因多态性.常规试剂盒测定血脂水平,包括血浆总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、甘油三酯(TG)和低密度脂蛋白胆固醇(LDL-C).飞行人员个人信息采用问卷调查.结果 飞行人员的血脂异常患病率为49.2%,高于国内普通人群的26.9%.飞行人员中ApoE等位基因e2的频率高于国内一般人群,而ε4的频率低于一般人群,ApoE基因多态性与TC、LDL-C、ApoB的水平相关,而和TG、HDL-C的水平关系不明显.在高TC和高LDL-C血脂异常组,等位基因ε3的频率高于TC和LDL-C正常组,而等位基因ε2的情况刚好相反.累计飞行时间在15 000 h以上的飞行人员与累计飞行时间在10 000 h以下的人员相比,TC、HDL-C均明显增高(P＜0.05),而TG、LDL-C亦有增高趋势,但未有统计学差异.Logistic回归分析提示,BMI和血脂异常的发生相关,而累计飞行时间与体重指数(BMI)相关,抽烟、运动、喝酒等因素未发现与血脂异常及BMI有关.结论 累计飞行时间是影响血脂水平的重要因素,累计飞行时间可以直接或间接地通过影响BMI而影响血脂水平.     

Route selection in barrier avoidance

BackgroundFajen and Warren’s steering dynamics model can reproduce human paths around an extended barrier by adding ‘waypoints’ at each end – if one waypoint is selected to minimize the global path curvature (Gérin-Lajoie and Warren, 2008). We propose that waypoint selection behaves like a choice between two competing goals, in which the smaller distance (d) and deviation angle (β) is preferred (Ulrich and Borenstein, 1998). Here we manipulate these two variables to test the determinants of route selection.Research questionHow does route selection in barrier avoidance depend on the local distance (d) and deviation angle (β) of each end, and on global path length (P) and curvature (C)? Methods: Participants (Exp1 N = 19; Exp2 N = 15) walked around a barrier to a visible goal in a virtual environment. Barrier orientation and lateral position were manipulated to vary the difference in distance (Δd) and in deviation angle (Δβ) between the left and right ends of the barrier. Left/Right route data were analyzed using a mixed-effects logistic regression model, with Δβ, Δd, and observed ΔP and ΔC as predictors.ResultsThe main effects of Δβ and Δd significantly predicted Rightward responses (p < .001), more strongly than ΔP and ΔC (ΔBIC = 29.5). When Δβ and Δd agreed, responses were toward the smaller distance and deviation (88% overall); when they conflicted, responses were in between (65% toward smaller β). The 75% choice threshold for Δβ was ±1.65˚, and for Δd was 0.75 m, from the 50% chance level.SignificanceDuring barrier avoidance, participants select a route that minimizes the local distance (d) and deviation angle (β) of the waypoint, rather than the global path length (P) or path curvature (C). These findings support the hypothesis that route selection is governed by competing waypoints, instead of comparing planned paths to the final goal.     

OSHA safety requirements for hazardous chemicals in the workplace

This article outlines the Occupational Safety and Health Administration (OSHA) requirements set forth by the Hazard Communication Standard, which has been in effect for the healthcare industry since 1987. Administrators who have not taken concrete steps to address employee health and safety issues relating to hazardous chemicals are encouraged to do so to avoid the potential of large fines for cited violations. While some states administer their own occupational safety and health programs, they must adopt standards and enforce requirements that are at least as effective as federal requirements.     

Assessing decision-making and capacity in minimally-aware patients

The assessment of decision-making by minimally-aware patients represents an important challenge for medicine, science and the law. This paper seeks to assist the dialogue between these disciplines by discussing three aspects: the difficulties inherent in establishing a reliable means of communication with the patient; the difficulty of exploring understanding and decision-making once a means of communication has been determined; and the legal implications including problems that may arise with the 'balance of probabilities' legal standard of proof. These aspects are discussed using the example of patients who have very severe acquired brain damage or are in states which verge on the 'persistent vegetative state'. The discussion is informed by existing case law and by reference to clinical method and scientific theory including binomial theory.     

Cold weather issues in sideline and event management

Exercise in cold environments exerts a unique physiologic stress on the human body, which, under certain conditions, may result in a cold-related injury. Environmental factors are the most important risk factors for the development of hypothermia in athletes. Frostbite occurs as a result of direct cold injury to peripheral tissues. The biggest risk for frostbite is temperature. Trench foot is a result of repeated and constant immersion in cold water. Chilblains are local erythematous or cyanotic skin lesions that develop at ambient air temperatures of 32°F to 60°F after an exposure time of about 1 to 5 h. Cold urticaria is, essentially, an allergic reaction to a cold exposure and can be controlled with avoidance of the cold. There are a number of risk factors and conditions that predispose athletes to cold injury, but exercise in the cold can be done safely with proper education and planning.     

Collision avoidance strategies between two athlete walkers: Understanding impaired avoidance behaviours in athletes with a previous concussion

BackgroundIndividuals who have sustained a concussion often display associated balance control deficits and visuomotor impairments despite being cleared by a physician to return to sport. Such visuomotor impairments can be highlighted in collision avoidance tasks that involves a mutual adaptation between two walkers. However, studies have yet to challenged athletes with a previous concussion during an everyday collision avoidance task, following return to sport.Research QuestionDo athletes with a previous concussion display associated behavioural changes during a 90°-collision avoidance task with an approaching pedestrian?MethodsThirteen athletes (ATH; 9 females, 23 ± 4years) and 13 athletes with a previous concussion (CONC; 9 females, 22 ± 3 years, concussion <6 months) walked at a comfortable walking speed along a 12.6 m pathway while avoiding another athlete on a 90º-collision course. Each participant randomly interacted with individuals from the same group 20 times and interacted with individuals from the opposite group 21 times. Minimum predicted distance (mpd) was used to examine collision avoidance behaviours between ATH and CONC groups.ResultsThe overall progression of mpd(t) did not differ between groups (p > .05). During the collision avoidance task, previously concussed athletes contributed less when passing second compared to their peers(p < .001). When two previously concussed athletes were on a collision course, there was a greater amount of variability resulting in inappropriate adaptive behaviours.SignificanceAlthough successful at avoiding a collision with an approaching athlete, previously concussed athletes exhibit behavioural changes manifesting in riskier behaviours. The current findings suggest that previously concussed athletes possess behavioural changes even after being cleared to returned to sport, which may increase their risk of a subsequent injury when playing.     

Exercise-induced asthma in the competitive cold weather athlete

Exercise-induced asthma (EIA) is a very common condition that affects winter sport athletes at rates as high as 50%. It has become clear that the main etiologic factors in EIA are the extremely low humidity and high respiratory rates in these athletes, which lead to extreme airway drying. New developments in objective testing for this condition have been recently described and are reviewed here. EIA is easily treated with oral and inhaled medications. These medications are closely regulated by the antidoping agencies; therefore, care must be taken by the treating physician to ensure compliance with the latest restrictions.     

Dual-tasking interferes with obstacle avoidance reactions in healthy seniors

Dual-tasking can lead to falls, as does a deterioration of obstacle avoidance (OA) skills. Hence, it is expected that a combination of both would be even more detrimental, especially when OA is time-critical. Previous studies confirmed this expectation, however, due to several limitations in their design it is yet too early to draw any definitive conclusions on the allocation of attentional resources in OA under dual-task conditions. Therefore, attentionally demanding primary and secondary tasks were used with the instruction to perform as well as possible on both tasks. Nineteen healthy senior individuals (60±4.7 years, 8 females) performed an OA task on a treadmill while walking at 3 km/h as a single task and combined with an auditory Stroop task. Biceps femoris (BF) muscle response times, OA failure rates and composite scores were used to evaluate the data. Increased OA failure rates (3%, p=0.03) and delayed BF response times (21 ms, p<0.001) were found under dual-task conditions. Composite scores were reduced during (p<0.001) and just after obstacle crossing (p=0.003). In conclusion, dual-tasking during time-critical OA affects the motor as well as the cognitive task when subjects are instructed to keep up performance on both tasks. This adds to the evidence indicating an increased risk of tripping or falling when attention is divided during walking in the presence of unexpected obstacles.     

Fluid replacement recommendations for training in hot weather.

The U.S. Army's fluid replacement guidelines emphasize fluid replacement during hot weather training to prevent degradation of performance and minimize the risk of heat injury. Little consideration has been given, however, to possible overhydration and development of water intoxication. Sufficient epidemiological evidence is available to demonstrate an increasing incidence of water intoxication during military training. This article summarizes the development and validation of revised fluid replacement guidelines for hot weather training. The end product is an easy-to-read table that provides the user with the appropriate hourly work time and fluid intake to support work during hot weather training. The guidelines include the range of hot weather conditions likely to be encountered during military training and cover a broad range of military activities. It is expected that the revised guidelines will sustain hydration and minimize the number of heat injuries during military training while protecting the soldier from becoming sick from overdrinking.