Physiological responses to simulated firefighter exercise protocols in varying environments

For decades, research to quantify the effects of firefighting activities and personal protective equipment on physiology and biomechanics has been conducted in a variety of testing environments. It is unknown if these different environments provide similar information and comparable responses. A novel Firefighting Activities Station, which simulates four common fireground tasks, is presented for use with an environmental chamber in a controlled laboratory setting. Nineteen firefighters completed three different exercise protocols following common research practices. Simulated firefighting activities conducted in an environmental chamber or live-fire structures elicited similar physiological responses (max heart rate: 190.1 vs 188.0 bpm, core temperature response: 0.047°C/min vs 0.043°C/min) and accelerometry counts. However, the response to a treadmill protocol commonly used in laboratory settings resulted in significantly lower heart rate (178.4 vs 188.0 bpm), core temperature response (0.037°C/min vs 0.043°C/min) and physical activity counts compared with firefighting activities in the burn building.

Practitioner Summary: We introduce a new approach for simulating realistic firefighting activities in a controlled laboratory environment for ergonomics assessment of fire service equipment and personnel. Physiological responses to this proposed protocol more closely replicate those from live-fire activities than a traditional treadmill protocol and are simple to replicate and standardise.     

Physiological and cognitive responses when riding an electrically assisted bicycle versus a classical bicycle

The present study compared the physiological responses and the subsequent cognitive performance when riding an electrically assisted (EB) versus a classical (CB) bicycle. Oxygen uptake, heart rate and leg extensor muscles electromyographic (EMG) activity were recorded in 10 subjects during a 30-min intermittent cycling exercise performed with EB versus CB. Cognitive performance was evaluated by a mail sorting test, performed at rest and after each cycling session. Averaged oxygen uptake and heat rate were significantly (P < 0.05) lower during EB cycling than during CB cycling. The EMG activities of the vastus lateralis, rectus femoris and gastrocnemius medialis muscles were significantly (P < 0.001) greater during CB cycling than during EB cycling. The time to complete the mail sorting test was significantly (P < 0.05) shorter after EB cycling than after CB cycling. Because EB cycling reduced muscle strains and physiological stress, it might offer benefits for those using bicycles in their work, such as postal workers and police officers. STATEMENT OF RELEVANCE: This study compared physiological and cognitive responses when riding an electrically assisted versus a classical bicycle. The results showed that the electrically assisted bicycle led to reduced muscle strains and physiological stress and, therefore, might offer benefits for those using bicycles in their work, such as postal workers and police officers.     

Use of pressure insoles to compare in-shoe loading for modern running shoes

The primary objective of this paper was to compare in-shoe loading for different models of running shoe using measurements of force distribution. It was hypothesised that a shoe designed with minimal focus on cushioning would demonstrate significantly higher peak forces and rates of loading than running shoes designed with cushioning midsoles. Loading was compared using in-shoe peak forces for six footwear conditions. It was found that peak rate of loading at the heel provided clear distinctions between shoes. In support of the study hypothesis, the shoe with minimal focus on cushioning had a significantly higher rate of loading than all but one of the other test shoes. Data collected for midfoot and forefoot areas of the foot highlighted the importance of considering loading across the foot surface. The results of the present study demonstrate that pressure insoles provide a useful tool for the assessment of loading across the foot plantar surface for different footwear conditions. There are numerous models of running shoe for individuals to select from, with limited information available regarding the performance of the shoes during running. The current study demonstrates differences in loads across the foot plantar surface during running, indicating differences in performance for different footwear models.     

Biological and psychological responses to two rapid shiftwork schedules

This study presents the biological responses to shiftwork in two groups of workers with different shiftwork rotas. Biological responses were studied by recording the heart rate and the changes in the circadian profile of salivary cortisol over 24?h (RIA assays). Various items were recorded through questionnaires aimed at determining self appreciation of sleep quantity, stress, health, satisfaction at work and in private lives. Thirty two male subjects aged from 23 to 56, working for the same company, having given their informed consent, took part in the study. The study was carried out under realistic conditions (at the work place) under the control of an occupational physician. Sixteen day-workers (8 am?–?6?pm) served as a reference group. Eight shiftworkers included in alternate schedules (morning M 4 am?–?12 am, evening E 12 am?–?8?pm, night N 8?pm?–?4 am) according to a system M, S, N 3/2, (3 work, 2 rest) and eight according to a system 7/5 (3M/2S/2N/5R, 2/3/2/5, 2/2/3/5) constituted the groups of shiftworkers respectively named 3/2 and 7/5. All subjects had comparable ages and BMIs. Shiftworkers expressed a higher stress level and frequency of health problems and a lower satisfaction at work than the control. Among the three groups, the 7/5 group had the best health and fitness score and was in need of less sleep. Heart rate was not affected by shift work. Conversely, consistent changes appeared in cortisol circadian profiles, the greatest changes appearing for the night shift and among the two groups of shiftworkers, more particularly for the 7/5 group. These changes correlated with self-perceived constraints of work and showed the difficulties of adaptation to shiftwork.     

Comparison of Skidding Performance of Small Track-type Experimental Prototype Skidder and J-50 Skidding Tractor

In this paper, field experimental comparison is made between a small track-type experimental prototype skidder and a J-50 skidding tractor. Experimental data, including skidding productivity, soil compaction on skidding trails, and damage rate of the residual trees, are analyzed. The results indicate that with the condition of scattered skidding area and low skidding volume per cycle, small track-type experimental prototype skidder has advantage on working and a higher skidding productivity. It makes lower soil compaction to the skidding trails in the depth of 0-5 cm, 5-10 cm, and 10-15 cm. Under the same work conditions, the damage rate of the residual trees made by small track-type experimental prototype skidder is only 1/5 of those made by J-50 type skidding tractor. The damage rate is reduced by 80%.     

河南省对外汉语专业本科生就业问题及对策探析

分析了影响对外汉语专业毕业生就业的各种因素,主张以积极的心态看待就业形势,正视存在的问题,加强专业建设,优化课程设置,落实实践环节,提升专业素质和求职技能,以提高对外汉语专业学生就业率和就业质量。     

焦石坝超长水平井测井资料处理方法

在页岩气的开发中,为了获得更高产能,超长水平井的应用成为必然。超长水平井的垂深计算受地层倾角影响较大,计算垂深时必须考虑地层倾角的影响。当井斜大于90°时,常规垂深计算方法会出现数据丢失现象,对地层对比造成困扰。通过建立校正模型,根据地层倾角分别对井斜及大于90°的井斜进行校正,再根据校正后的数据计算垂深,可较好的消除地层倾角的影响及当井斜大于90°时的数据丢失现象,保证了水平井眼轨迹计算分析的正确性,也为后期压裂改造提供支持。     

活性炭对原水中有机污染物去除效果的研究

文中针对原水水质特点,利用常规+活性炭吸附工艺对原水进行处理,着重分析了活性炭对有机物的去除效果。     

一种新型ICA算法在RFID系统中的应用

针对无线射频识别系统在通信过程中的防碰撞问题,从信号处理的角度,提出一种基于盲源信号并行分离技术的防碰撞处理算法,其中包括信号白化技术,以及一种改进的独立元分析(ICA)信号并行分离方法.功能仿真结果证明,该算法的吞吐率最高达到69％,与吞吐率只有18％的传统Aloha算法相比,该算法能提高防碰撞能力.