The Role of Rhythmic Systems in the Adaptation of Fiddler Crabs to the Intertidal Zone

Fiddler crabs inhabiting the intertidal zone must adapt theiractivity to both the day-night cycle and the cycle of the tides.The tidal cycle imposes on the animals a rhythmic alternationbetween terrestrial and marine periods of existence. At thesame time the crabs are influenced by the day-night cycle, sincethey exhibit specific diurnal and nocturnal habits. Moreover,the interaction of daily and tidal rhythms may give rise tosemi-monthly variations in activity. It is now well established that persistent daily and tidal rhythmsin physiological processes underlie rhythmic variations in thebehavior of crabs in the field. The present paper reviews morerecent studies, which have compared the persistent rhythms incrabs from different tidal and non-tidal regions. Rhythmic patternsrecorded in the laboratory are found to be closely correlatedwith tidal conditions in the native habitat of the crabs. Ithas also been shown that the persistent pattern can be modifiedby transplanting crabs to the intertidal zone of another coastwhere they are exposed to tidal cycles which differ in formfrom those in the original habitat.     

Using Pattern Classification to Measure Adaptation to the Orientation of High Order Aberrations

Background

The image formed by the eye''s optics is blurred by the ocular aberrations, specific to each eye. Recent studies demonstrated that the eye is adapted to the level of blur produced by the high order aberrations (HOA). We examined whether visual coding is also adapted to the orientation of the natural HOA of the eye.

Methods and Findings

Judgments of perceived blur were measured in 5 subjects in a psychophysical procedure inspired by the “Classification Images” technique. Subjects were presented 500 pairs of images, artificially blurred with HOA from 100 real eyes (i.e. different orientations), with total blur level adjusted to match the subject''s natural blur. Subjects selected the image that appeared best focused in each random pair, in a 6-choice ranked response. Images were presented through Adaptive Optics correction of the subject''s aberrations. The images selected as best focused were identified as positive, the other as negative responses. The highest classified positive responses correlated more with the subject''s Point Spread Function, PSF, (r = 0.47 on average) than the negative (r = 0.34) and the difference was significant for all subjects (p<0.02). Using the orientation of the best fitting ellipse of angularly averaged integrated PSF intensities (weighted by the subject''s responses) we found that in 4 subjects the positive PSF response was close to the subject''s natural PSF orientation (within 21 degrees on average) whereas the negative PSF response was almost perpendicularly oriented to the natural PSF (at 76 degrees on average).

Conclusions

The Classification-Images inspired method is very powerful in identifying the internally coded blur of subjects. The consistent bias of the Positive PSFs towards the natural PSF in most subjects indicates that the internal code of blur appears rather specific to each subject''s high order aberrations and reveals that the calibration mechanisms for normalizing blur also operate using orientation cues.     

Electroconvulsive Shock and Cyclic AMP Signal Transduction: Effects Distal to the Receptor

Chronic electroconvulsive shock (ECS) induced a significant decrease in noradrenaline- and forskolin-stimulated cyclic AMP production in rat cortical slices, whereas a single ECS had a much smaller effect. In a cortical membrane preparation, adenylate cyclase activity in response to stimulation by forskolin, guanosine-5'-(beta,gamma-imido) triphosphate, and Mn2+ ions was significantly increased in membranes derived from rats that had received chronic ECS, but was either unchanged or reduced in membranes from rats that received a single treatment only. The results are interpreted in terms of changes occurring at components of the adenylate cyclase enzyme distal to the receptor.     

Internal Desynchronization of Circadian Rhythms and Tolerance to Shift Work

Intolerance to shift work may result from individual susceptibility to an internal desynchronization. Some shift workers (SW) who show desynchronization of their circadian rhythms (e.g., sleep‐wake, body temperature, and grip strength of both hands) exhibit symptoms of SW intolerance, such as sleep alteration, persistent fatigue, sleep medication dependence, and mood disturbances, including depression. Existing time series data previously collected from 48 male Caucasian French SW were reanalyzed specifically to test the hypothesis that internal synchronization of circadian rhythms is associated with SW intolerance and symptoms. The entry of the subjects into the study was randomized. Three groups were formed thereafter: SW with good tolerance (n=14); SW with poor tolerance, as evident by medical complaints for at least one year (n=19); and former SW (n=15) with very poor tolerance and who had been discharged from night work for at 1.5 yr span but who were symptom‐free at the time of the study. Individual and longitudinal time series of selected variables (self‐recorded sleep‐wake data using a sleep log, self‐measured grip strength of both hands using a Colin Gentile dynamometer, and oral temperature using a clinical thermometer) were gathered for at least 15 days, including during one or two night shifts. Measurements were performed 4–5 times/24 h. Power spectra that quantify the prominent period (τ) and t‐test, chi square, and correlation coefficient were used as statistical tools. The mean (±SEM) age of SW with good tolerance was greater than that of SW with poor tolerance (44.9±2.1 yrs vs. 40.1±2.6 yrs, p<.001) and of former SW discharged from night work (very poor tolerance; 33.4±1.7, p<.001). The shift-work duration (yrs) was longer in SW with good than poor tolerance (19.9±2.2 yrs vs. 15.7±2.2; p<0.002) and former SW (10.7±1.2; p<.0001). The correlation between subject age and shift-work duration was stronger in tolerant SW (r=0.97, p<.0001) than in non‐tolerant SW (r=0.80, p<0.001) and greater than that of former SW (r=0.72, p<.01). The mean sleep‐wake rhythm τ was 24 h for all 48 subjects. The number of desynchronized circadian rhythms (τ differing from 24 h) was greater in non‐tolerant than in tolerant SW (chi square=38.9, p<.0001). In Former SW (i.e., 15 individuals assessed in follow‐up studies done 1.5 to 20 yrs after return to day work), both symptoms of intolerance and internal desynchronization were reduced or absent. The results suggest that non‐tolerant SW are particularly sensitive to the internal desynchronization of their circadian time organization.     

心电、呼吸信号采集分析系统的研制

设计一种用于移动监护系统的生理信息采集及预处理装置。该装置以ARM为核心,包括低功耗的双路心电信号放大、滤波、抗基线漂移电路。实现了心电信号的采集、预处理、简单分析及从心电信号中提取呼吸信号等功能。     

A Triangulation Approach to Checking the Reliability of Estimation of Oscillatory Modes Embedded in an ECG Signal

Biophysics - Abstract—It is important to perform an analytical study of the oscillatory modes embedded in an ECG signal on individuals in certain occupations (power station operators, pilots,...     

獐(Hydropotes inermis)的警戒行为模式及逃跑起始距离的适应性变化

为了掌握獐的警戒行为特征并为重引入项目提供管理依据,以人为干扰源观察獐的警戒反应,发现其警戒模式包括听 (listen) 或扫视 (scan) ,盯视 (stare) ,走开 (walk away) ,跑开 (run away),吼叫 (bark) 和压脖 (stretch) 。利用逃跑起始距离对上海松江圈养 (自由采食) 獐、上海华夏圈养(人工饲喂) 獐和江苏盐城野生獐进行警戒性比较,得出：人工饲喂獐警戒性最小,野生獐警戒性最大。可通过野化训练提高人工饲喂獐的警戒性;人类活动、种群密度、围栏和区域面积可能影响獐的警戒性。     

Circadian Adaptation to Night Shift Work Influences Sleep,Performance, Mood and the Autonomic Modulation of the Heart

Our aim was to investigate how circadian adaptation to night shift work affects psychomotor performance, sleep, subjective alertness and mood, melatonin levels, and heart rate variability (HRV). Fifteen healthy police officers on patrol working rotating shifts participated to a bright light intervention study with 2 participants studied under two conditions. The participants entered the laboratory for 48 h before and after a series of 7 consecutive night shifts in the field. The nighttime and daytime sleep periods were scheduled during the first and second laboratory visit, respectively. The subjects were considered “adapted” to night shifts if their peak salivary melatonin occurred during their daytime sleep period during the second visit. The sleep duration and quality were comparable between laboratory visits in the adapted group, whereas they were reduced during visit 2 in the non-adapted group. Reaction speed was higher at the end of the waking period during the second laboratory visit in the adapted compared to the non-adapted group. Sleep onset latency (SOL) and subjective mood levels were significantly reduced and the LF∶HF ratio during daytime sleep was significantly increased in the non-adapted group compared to the adapted group. Circadian adaptation to night shift work led to better performance, alertness and mood levels, longer daytime sleep, and lower sympathetic dominance during daytime sleep. These results suggest that the degree of circadian adaptation to night shift work is associated to different health indices. Longitudinal studies are required to investigate long-term clinical implications of circadian misalignment to atypical work schedules.     

Detection of Cyclic Trends in Incidence Data Using the Efficiency Score Method

In studies involving a cyclic regularity, researchers usually have a good working knowledge regarding the peak time in the cycle. Capitalizing on this information, we derive the asymptotically uniformly most powerful unbiased test for detecting a cyclic trend using the likelihood score, and present the asymptotic power function of the test and the approximate formula for sample size. Numerical studies demonstrate great advantages of the proposed test over the standard test in terms of power and sample size. Asymptotic power of the score test is satisfactorily close to actual power. We also generalize this method so that it is applicable for incidence data from unequally spaced intervals or risk populations of unequal size.     

信号肽对外源蛋白分泌效率的影响

信号肽在引导外源蛋白分泌过程中具有重要作用,本文从信号肽疏水性结构、构建分泌型载体以及分泌增强子、定位信号等几个方面介绍了信号肽对外源蛋白分泌效率的影响,在大量生产以酵母为表达宿主的治疗性蛋白方面具有广泛的应用前景。     

以单床工作效率为核心的医院床位效能评价模型研究

目的 探讨单床工作效率指标在评价医院床位利用效率的应用及可行性,建立床位效能评价模型,为科学、有效的床位利用与评估提供依据。方法 提出单床工作效率概念,建立新的床位效能评价模型,分析2015年某院床位利用情况。结果 单床工作效率在评价床位利用效能方面优于其他指标,新的医院床位效能评价模型评价更为客观、准确。结论 单床工作效率为核心的医院床位效能评价模型具有更好的可比性和操作性,可在医院精细化管理中推广使用。     

公立医院内部审计理念与工作思路调查分析

全面了解公立医院内部审计理念和工作思路现状。文章通过对河南省408家公立医院调查问卷的设计、发放和回收,利用SPSS软件对调查数据进行归类统计,深入研究实质缺陷和不足的成因。进一步阐述了创新公立医院内部审计理念的路径选择,即深刻把握内部审计理念内涵、强化制度基础审计和风险导向审计的理念、充分发挥培养财务及管理人才方面的作用及完善内部审计手册等。     

Identification,Characterization, and Structure Analysis of the Cyclic di-AMP-binding PII-like Signal Transduction Protein DarA

The cyclic dimeric AMP nucleotide c-di-AMP is an essential second messenger in Bacillus subtilis. We have identified the protein DarA as one of the prominent c-di-AMP receptors in B. subtilis. Crystal structure analysis shows that DarA is highly homologous to P_II signal transducer proteins. In contrast to P_II proteins, the functionally important B- and T-loops are swapped with respect to their size. DarA is a homotrimer that binds three molecules of c-di-AMP, each in a pocket located between two subunits. We demonstrate that DarA is capable to bind c-di-AMP and with lower affinity cyclic GMP-AMP (3′3′-cGAMP) but not c-di-GMP or 2′3′-cGAMP. Consistently the crystal structure shows that within the ligand-binding pocket only one adenine is highly specifically recognized, whereas the pocket for the other adenine appears to be promiscuous. Comparison with a homologous ligand-free DarA structure reveals that c-di-AMP binding is accompanied by conformational changes of both the fold and the position of the B-loop in DarA.