CONSEQUENCES OF SHIFTWORKING ON SLEEP DURATION,SLEEPINESS, AND SLEEP ATTACKS

Rotating shift and permanent night work arrangements are known to compromise sleep. This study examined the effects of work schedule on sleep duration, excessive sleepiness, sleep attacks, driving, and domestic/professional accidents. A representative sample of the general population of the state of New York—3,345 individuals ≥18 yrs of age—was interviewed by telephone regarding their sleep and psychiatric and organic disorders. Multivariate models were applied to derive odds ratios (OR) after adjustment for age, sex, physical illness, mental disorders, obstructive sleep apnea, and sleep duration. On average (±SE), workers slept 6.7?±?1.5?h, but 40% slept <6.5?h/main sleep episode. Short-sleep duration (<6?h) was strongly associated with fixed night (OR: 1.7) and day-evening-night shiftwork arrangement (OR: 1.9). Some 20% of the workers manifested excessive sleepiness in situations requiring high attention, and it was associated with the fixed night (OR: 3.3) and day-evening-night work arrangements (OR: 1.5). Overall, 5% of the workers reported sleep attacks; however, they occurred three-times more frequently in the fixed night (15.3%) than other work arrangements (OR: 3.2). Driving accidents during the previous 12 months were reported by 3.6% of the workers and were associated with fixed night (OR: 3.9) and day-evening-night (OR: 2.1) work schedules. The findings of this study indicate that working outside the regular daytime hours was strongly associated with shorter sleep duration, sleepiness, and driving accident risk. Night work is the most disrupting, as it is associated with insufficient sleep during the designated rest span and excessive sleepiness and sleep attacks during the span of activity, with an associated consequence being increased driving accident risk. (Author correspondence: mohayon@stanford.edu)     

Association between misalignment of circadian rhythm and obesity in Korean men: Sixth Korea National Health and Nutrition Examination Survey

ABSTRACT

Background: The disruption of circadian rhythm has been found to associate with obesity in vivo and in vitro. Sleep duration, eating habits, total feeding time, and nightshift work can also affect circadian rhythms. This study investigated the association between misalignment of circadian rhythm and obesity in Korean men, using a cross-sectional database.

Methods: This study used data from the Korean National Health and Nutrition Examination Survey (KNHANES), whose study population was 3,658 men aged 18 to 60 years. General and abdominal obesity was defined as a body mass index (BMI) ≥ 25 kg/m² and waist circumference ≥ 90 cm, respectively. Circadian rhythm factors were determined with a self-report questionnaire and included breakfast frequency, sleep duration, and work time. Frequency of breakfast was divided into regular breakfast (five to seven times a week) and irregular breakfast (less than five times a week). Sleep duration was divided into less than 7 hours, 7–9 hours, and over 9 hours. Working time was defined as day/evening, night shift, and other type. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for general and abdominal obesity were calculated using multivariable logistic regression according to the number of factors that disturb the circadian rhythm.

Results: Participants with 1 (aOR 1.34, 95% Cl 1.10–1.61) and ≥2 (aOR 1.62, 95% Cl 1.29–2.05) factors disturbing circadian rhythms were associated with elevated risk for general obesity. Similarly, those with 1 (aOR 1.33, 95% Cl 1.09–1.63) and ≥2 (aOR 1.70, 95% Cl 1.32–2.20) factors had elevated risk for abdominal obesity.

Conclusions: Factors disturbing the circadian rhythm were associated with general and abdominal obesity. Additional studies are needed, and associations with metabolic diseases should be investigated.     

退化高寒草甸关键生态属性对多途径恢复措施的响应特征

高寒草甸是青藏高原的主体植被类型，但退化态势较为严峻，严重威胁青藏高原生态屏障的战略地位。退化高寒草甸的复健是世界性难题，治理效果也因退化状态、恢复措施及气候环境而异。以春季休牧、秋季休牧、畜群结构优化、减畜轮牧、围栏封育及翻耕改建等典型多途径恢复措施下的退化高寒草甸为对象，系统探讨主要生态要素和生态功能的响应特征及潜在过程。结果表明，典型恢复措施下退化高寒草甸的植被生产力、土壤有机碳密度及土壤饱和持水量等生态要素都得到一定程度的提升，而恢复效果与实施年限及恢复措施密切相关。围栏封育和翻耕改建下土壤有机碳密度及饱和持水量随恢复年限均表现为对数饱和型的响应特征，退化高寒草甸固碳持水功能的基本恢复年限约为6—10年。春季休牧、秋季休牧、畜群结构优化、减畜轮牧、围栏封育等放牧管理恢复措施应适用于轻度退化至重度退化的高寒草甸，而翻耕改建则是极度退化高寒草甸的适宜治理措施。由于多途径恢复措施的关注目标不同，今后研究应集中在恢复措施的组合优化和综合评价等方面。     

Pelagic larval duration of 10 temperate cryptobenthic fishes

The pelagic larval duration ( D _PL) for 10 temperate cryptobenthic species belonging to three families: Gobiidae, Gobiesocidae and Blenniidae was investigated. Overall, the Gobiesocidae presented short D _PLs varying between 11 and 18 days, the Gobiidae's D _PL ranged between 14 and 39 days, and Parablennius pilicornis (Blenniidae) had an average of 33 days (range 31–37 days). Two subtypes of settlement marks were found among individuals of the same species.     

白纹伊蚊幼虫龄期的发育历期

在实验室内20±1℃, 23±1℃, 25±1℃, 28±1℃和30±1℃恒温条件下, 观察了白纹伊蚊(Aedes albopictus)幼虫(广州株)的发育历期.幼虫的总发育历期和各龄幼虫的发育历期随温度的上升而缩短, 各龄幼虫历期在总发育历期中占有恒定的百分比, 据此计算出其捕获机率.各龄幼虫的发育历期与温度呈直线回归关系.通过积温公式, 求出各龄幼虫的积温常数.此外还探索了营养对幼虫发育历期的影响, 从而影响各龄幼虫捕获机率的计算.     

The problem of the acts duration measurement in relation to the “focal-animal” technique of behavioral recording

The focal-animal technique assumes the continuous recording of the behavior of an individual during a certain time interval. The length of this interval (sampling unit) can be problematic when estimating the duration of behavioral acts. Two acts from the behavioral repertoire of the ant Leptothorax fuenteiwere focused on in this work at different ranges of temporal scales. Analyzing these acts we show the possibility of existence of a sampling artifact, in such a way that the estimates of the durations of the acts would be forced to depend upon the length of the sampling unit that is being used.     

Embryonic development times of entomostracan zooplankton from Lake le Roux (Orange River,South Africa), and their possible relationships to seasonal succession

Embryonic development times of the principal entomostracan zooplankton of Lake le Roux, Orange River, South Africa, are described. Durations decreased monotonically with temperature over the thermal tolerance range and are described using Blehrádek's equation. The present data are compared with other observations on rate-temperature responses of warm-water and temperate zooplankton. Small, but ecologically significant, differences are discerned. The possible significance of species-specific rate-temperature responses to the phenomenon of seasonal succession is explored.     

Regulation by kinetin and abcisic acid of correlative senescence in relation to grain maturation,source-sink relationship and yield of rice (Oryza sativa L.)

When kinetin was applied to the source organ (flag leaf) of rice (Oryza sativa L. cv. Ratna), foliar senescence was delayed and grain yield per plant (as evidenced by grain weight, grain/straw weight ratio and 1,000 grain growth) was increased through the increase of sink activity (increase in dry weight of the grains/plant), duration of sink capacity as well as photosynthetic ability of the glumes (as determined by the chlorophyll content of the glumes of the developing grains). However, application of kinetin to the sink organs (fruits), promoted senescence of the source but increased the yield by increasing the sink capacity and 1,000 grain growth mostly at the earlier stage of reproductive development. Lower sterility percentage was associated with higher grain yield of the plant by kinetin treatments. ABA applied either to the source or the sink promoted leaf senescence and reduced the grain yield by reducing the sink activity, harvest index, sink capacity duration and increasing the sterility percentage. Thousand grain dry weight at harvest did not vary significantly amongst the treatments. It was concluded that nutrient drainage was associated with the correlative influence of fruit on the monocarpic senescence of rice plant and that a competetion for differential allocation of cytokinin and ABA in the source and sink organs initiates this senescence syndrome.