Suchergebnisse

The production of limitless carbon-free energy is a long-sought dream of scientists and politicians alike. One strategy for achieving this aim is the production of hydrogen by photosynthetic microorganisms – harnessing the effectively limitless power of the sun to power our cars, toasters and PCR machines. It may be tempting to think of host expression systems as miniature factories given over entirely to the production our molecule of interest. However, the biological nature of the host must be taken into account if we are to maximize productivity. The circadian rhythm, an organism's entrainable oscillation of biological processes with a period of around 24 hours, is one such aspect that has received scant attention but is likely to be of particular importance to photosynthetic host systems. In this issue of current biology Xu et al. describe how our knowledge of the Synechococcus elongatus circadian clock can be leveraged to improve the production of exogeneous proteins, including those involved in the production of hydrogen [1].

Après un rappel sur les facteurs influençant les variations de performance, facteurs endogènes avec les horloges biologiques et externes avec en particulier le temps écoulé depuis le réveil, il est fait mention d'une technique permettant de séparer les influences respectives de ces deux facteurs ouvrant ainsi la voie à une description mathématique (au sein d'un modèle additif) des composantes des facteurs qui entrent en jeu dans les variations de performance.
Toutefois, pour certains types de performances, le modèle additif ne sera pas adéquat, des interactions devant, dans certains cas, être prises en compte.
Ces résultats pourraient être utilisés pour faire des prédictions concernant diverses performances, compte tenu du système d'alternance de travail, et pour les confronter aux données obtenues sur le terrain.
Ces mêmes résultats semblent conforter l'idée que l'aménagement optimal des séquences de travail dépend de la nature de la tâche du travailleur.

Human behavior is not constant over the hours of the day, and there are considerable individual differences. Some people raise early and go to bed early and have their peek performance early in the day ("larks") while others tend to go to bed late and get up late and have their best performance later in the day ("owls"). In this contribution we report on three projects on the role of chronotype (CT) in language processing and learning. The first study (de Bot, 2013) reports on the impact of CT on language learning aptitude and word learning. The second project was reported in Fang (2015) and looks at CT and executive functions, in particular inhibition as measured by variants of the Stroop test. The third project aimed at assessing lexical access in L1 and L2 at preferred and non-preferred times of the day. The data suggest that there are effects of CT on language learning and processing. There is a small effect of CT on language aptitude and a stronger effect of CT on lexical access in the first and second language. The lack of significance for other tasks is mainly caused by the large interindividual and intraindividual variation.

The article of record as published may be found at http://dx.doi.org/10.1007/s41105-015-0003-0 ; The case of a 29-year-old active duty US Navy sailor with severe sleepiness is presented. He was diagnosed with mild obstructive sleep apnea which did not fully explain his sleepiness. At follow-up, positive airway pressure usage demonstrated a progressive, variable phase delay. His sleep periods aligned with his 5-h on/10-h off (5/10) military duty schedule. Treatment with bright light exposure and melatonin resolved his circadian arrhythmia. While it is known that military personnel are habitual shift workers who receive insufficient sleep, there is little documentation of shift work disorders in this population.

A field investigation was conducted concerning the impact of Yoga practice and Circadian Rhythmic impact on Span of Attention of the subjects. All the subjects were randomly selected from different Yoga practicing center throughout Orissa. They are divided into two groups like Yoga practicing groups (n=40) and Non-Yoga practicing Group (n=40). All the subjects are tested individually for four times in a day like morning, noon, evening and night, for their span of attention test. The analysis of results basing on their average span of attention score revealed that both the groups differed significantly with regard to their circadian Rhythmic impact. However, interaction impact is not found to be statistically significant which revealed the idea that the activity and arousal level may have certain other physiological aspects to be explored further.

People who are totally blind are prone to a cyclic form of insomnia, designated in medical terminology as non-24-hour sleep-wake syndrome. It is caused by a lack of synchrony between the internal body clock and the daily sleep-wake schedule. This article describes the clinical features and biological basis of the disorder and discusses the implications for its management and treatment.

Abstract
This systematic review investigates the bidirectional relationship between alcohol consumption and disrupted circadian rhythms. The goal of this study was to identify (i) the types of circadian rhythm disruptors (i.e. social jet lag, extreme chronotypes, and night shift work) associated with altered alcohol use and (ii) whether sex differences in the consequences of circadian disruption exist. We conducted a search of PubMed, Embase, and PsycINFO exclusively on human research. We identified 177 articles that met the inclusion criteria. Our analyses revealed that social jet lag and the extreme chronotype referred to as eveningness were consistently associated with increased alcohol consumption. Relationships between night shift work and alcohol consumption were variable; half of articles reported no effect of night shift work on alcohol consumption. Both sexes were included as participants in the majority of the chronotype and social jet lag papers, with no sex difference apparent in alcohol consumption. The night shift research, however, contained fewer studies that included both sexes. Not all forms of circadian disruption are associated with comparable patterns of alcohol use. The most at-risk individuals for increased alcohol consumption are those with social jet lag or those of an eveningness chronotype. Direct testing of the associations in this review should be conducted to evaluate the relationships among circadian disruption, alcohol intake, and sex differences to provide insight into temporal risk factors associated with development of alcohol use disorder.