营养成分对球孢白僵菌生长的影响

文章以查氏培养基为基本培养基,研究了不同碳源、氮源和不同微量元素对球孢白僵菌MZ050724菌株菌落生长和产孢量的影响.结果表明:8种碳源中单糖对该菌的生长有利,葡萄糖有利于菌落扩展和产孢量增加,菌落平均直径最大为5.069cm,产孢量最大为2.848×109个/mL;8种氮源中有机氮源比无机氮源对球孢白僵菌生长更好,其中酵母浸粉的菌落平均直径最大为7.4434cm,但硝态氮源硝酸钾对产孢量影响最大,为2.468×109个/mL;微量元素中硫酸锌对菌落生长有利,最大为7.718cm,硫酸锰产孢量最大为1.732×109个/mL.     

肉鸡猝死的病因分析与防制措施

1肉鸡猝死综合症的临床诊断1.1临床症状本病多发生于3—5周龄的雏鸡。患病鸡突然发病,平衡失调,两翅猛烈扑打,肌肉强痉挛,尖叫翻滚,呈仰卧姿势,头颈扭曲而亡。从发病到死亡经过不足一分钟。多发于生长快、外表健康、体状良好的鸡只。1.2病理变化对患病死亡后的鸡只剖检,发现冠髯和泄殖粘膜及脾脏充血,全身肌肉苍白,消化道内充满食物,肝脏肿大、质地易碎;肺肿大,弥漫淤血水肿,呈暗红色,气管内有泡沫状渗出物;心脏明显增大2—4倍,心肌松软,心包渗出液增多,静脉怒张。采集病料进行微生物培养阴性。1.3鉴别诊断本病与澳大利亚报道的肉鸡峰型死亡…     

Food intake and appetite following school-based high-intensity interval training in 9–11-year-old children

Using a randomised cross-over design, free-living lunch intake and subjective appetite were examined in 10 children (9.8 ± 0.6 years) following high-intensity interval training (HIIT) versus a control sedentary (SED) period, within a school setting. The 22-min HIIT took place during a regular PE lesson and consisted of two rounds of 4 × 30 s sprints. Foods were offered at a regular school lunch immediately following HIIT and SED and were matched between conditions. All food was covertly weighed before and after the meal. Hunger, fullness and prospective consumption were reported immediately before and after HIIT/SED, using visual analogue scales. Heart rate was higher during HIIT than SED (159.3 ± 23.1 vs. 76.9 ± 2.2 bpm, P < 0.05). Lunch energy intake was not different (P = 0.52) following HIIT, compared to SED (2.06 ± 0.35 vs. 2.09 ± 0.29 MJ, respectively). There were no significant differences in macronutrient intake or subjective appetite (P > 0.05). Results suggest that HIIT can be implemented in a PE lesson immediately before lunch, without causing a compensatory increase in food consumption.     

HMB与运动能力

HMB（β-羟基-β丁酸甲酯）是亮氨酸代谢的中间产物，能促进蛋白质合成和减少其分解，使机体力量增加，加快脂肪消耗，延缓肌肉疲劳，有助于提高耐力，是一种增加力量，增大肌肉体积，减少体脂的新型营养补剂。现从HMB的来源、作用和与运动训练的关系几方面作一论述，为HMB的合理使用提供参考。     

流动儿童和留守儿童的生长发育与营养状况分析

目的：了解流动和留守儿童的生长发育和营养状况及二者之间的关系,为促进儿童的健康提供依据和政策参考。方法：采用分层整群抽样和方便抽样方法,使用测量法和问卷法测查3—9年级5174名在校学生的身高、体重及食物摄取状况。结果：（1）流动儿童发育状况相对较好,留守儿童发育迟缓率较高。（2）男生的超重率高于女生,流动儿童的消瘦率和超重率均较高。（3）在经济状况相当时,不同类型儿童的食物摄取状况总分仍然存在差异。（4）调查中的6种食物每周摄入4—7次的儿童发育迟缓率最低,每周摄入1—3次的儿童超重率相对较低。结论：留守儿童的发育不良问题较严重,流动儿童的营养过剩问题开始显现。营养摄入与儿童的发育关系密切,有必要帮助儿童形成健康的膳食结构,促进其良好发展。     

Changes in energy availability across the season in Division I female soccer players

Abstract

Low energy availability [(energy intake – exercise expenditure)/kg lean body mass], a component of the Female Athlete Triad, has been associated with menstrual disturbances and low bone mass. No studies have examined the energy availability of athletes across a season. The purpose of this study was to assess the prevalence of, and what contributes to, low energy availability in Division I female soccer players across a season. Nineteen participants aged 18–21 years (mean [Vdot]O_2max: 57.0 ± 1.0 mL · kg^?1 · min^?1) were studied during the pre, mid, and post season. Mean energy availability was overall lowest at mid season, and lower at mid than post season (35.2 ± 3.7 vs. 44.5 ± 3.7 kcal · kg^?1 lean body mass, P = 0.009). Low energy availability (<30 kcal · kg^?1 lean body mass) was observed in 5/19 (26.3%), 5/15 (33.3%), and 2/17 (11.8%) of participants during the pre, mid, and post season. Dietary energy intake was lower mid (P = 0.008) and post season (P = 0.022) than it was pre season (pre: 2794 ± 233 kcal · day^?1; mid: 2208 ± 156 kcal · day^?1; post: 2161 ± 143 kcal · day^?1). Exercise energy expenditure decreased significantly (P ≤ 0.001) over time (pre: 819 ± 57 kcal · day^?1; mid: 642 ± 26 kcal · day^?1; post: 159 ± 28 kcal · day^?1). Low energy availability was due to lower dietary energy intake at lunch during pre season (P = 0.014) and during lunch and dinner during mid season (P ≤ 0.030). Energy availability was inversely related to body dissatisfaction (r = ?0.62, P = 0.017) and drive for thinness (r = ?0.55, P = 0.041) during mid season. Although most Division I female soccer players are not at risk for low energy availability, a concerning proportion exhibited low energy availability at pre or mid season. Further studies are needed to explore strategies to prevent and monitor low energy availability in these athletes.     

Parallel assessment of nutrition and activity in athletes: Validation against doubly labelled water, 24-h urea excretion,and indirect calorimetry

Abstract

The assessment of nutrition and activity in athletes requires accurate and precise methods. The aim of this study was to validate a protocol for parallel assessment of diet and exercise against doubly labelled water, 24-h urea excretion, and respiratory gas exchange. The participants were 14 male triathletes under normal training conditions. Energy intake and doubly labelled water were weakly associated with each other (r = 0.69, standard error of estimate [SEE] = 304 kcal · day^?1). Protein intake was strongly correlated with 24-h urea (r = 0.89) but showed considerable individual variation (SEE = 0.34 g · kg^?1 · day^?1). Total energy expenditure based on recorded activities was highly correlated with doubly labelled water (r = 0.95, SEE = 195 kcal · day^?1) but was proportionally biased. During running and cycling, estimated exercise energy expenditure was highly correlated with gas exchange (running: r = 0.89, SEE = 1.6 kcal · min^?1; cycling: r = 0.95, SEE = 1.4 kcal · min^?1). High exercise energy expenditure was slightly underestimated during running. For nutrition data, variations appear too large for precise measurements in individual athletes, which is a common problem of dietary assessment methods. Despite the high correlations of total energy expenditure and exercise energy expenditure with reference methods, a correction for systematic errors is necessary for the valid estimation of energetic requirements in individual athletes.     

新一代大众1.4TSI发动机的技术革新

现代汽车发动机技术更新换代快,作为最新最有代表性的缸内直喷技术已越来越被广泛应用。大众新一代1.4TSI发动机比上一代1.4TSI发动机更能适应中国国情。新一代1.4TSI发动机改进成带进气冷却的进气系统,单增压的废气涡轮系统以及无回油漏燃油系统,性能更加优越。     

Use of Polarised Light Microscopy to Improve Conservation of Parchment

ABSTRACT

The preservation state of parchment primarily depends on the structure of the collagen fibre network, which in turn is responsible for optical anisotropy, i.e. birefringence. Polarised light microscopy can therefore be used as a non-invasive technique that allows recording of birefringence distribution in the parchment, which directly relates to stress–strain distribution. Using samples from diverse sources (commercial parchment, parchment used by restorers for book binding, and parchment fabricated for the purpose of this study), we assessed the capability of polarised light microscopy for various diagnostics. We performed, for instance, identification of gelatinised regions, layered or ?brous regions in parchment cross section, qualitative analysis of parchment fat content (lipids), observation of stress-induced patterns resulting from tensile tests, and observation of water diffusion. These proof-of-principle experiments extend the capability of polarised light microscopy far beyond its common use and open the path to its deployment in conservation studies.