Circaseptan

OBJECTIVE: To study whether the menstrual cycle has a circaseptan (7 days) rhythm and whether it is associated with the lunar cycle (also defined as the synodic month, it is the cycle of the phases of the Moon as seen from Earth, averaging 29.5 days in length). DESIGN: Cross-sectional study. SUBJECTS: A total of 35,940 European and North American women aged 18-40 years. EXPOSURE: Data were collected in real-life conditions...

In a previous integrative single-case study, we collected biological, psychological and social time-series data on a 25-year-old healthy woman over the course of 126 12-h intervals (63 days) and used urinary neopterin as an indicator of cellular immune activity [Schubert et al. 2012 (1)]. The present re-evaluation introduced Dynamic Complexity (DC) as an additional non-linear and non-stationary measure to further investigate the subject's biopsychosocial dynamics during the study. The new time series dealing with urinary neopterin complexity revealed a cyclic, circaseptan (about-weekly) repeating pattern (6...

The study of temporal trajectories of emotions shared in tweets has shown that both positive and negative emotions follow nonlinear circadian (24 h) and circaseptan (7-day) patterns. But to this point, such findings could be instrument-dependent as they rely exclusively on coding using the Linguistic Inquiry Word Count. Further, research has shown that self-referential content has higher relevance and meaning for individuals, compared with other types of content. Investigating the specificity of self-referential material in temporal patterns of emotional expression in tweets is of interest, but current research is based upon generic textual productions...

BACKGROUND: Headache is a leading reason for presentation to the emergency department (ED) with migraine being the most frequently diagnosed headache. To ensure the adequate staffing of healthcare providers during peak times of headache visits, we analyzed the temporal distribution of emergency department visits in patients presenting with headache and/or migraine. RESEARCH DESIGN AND METHODS: The authors conducted an ecological study, including all consecutive visits to the ED for headache...

The analysis of systematically collected data for coronavirus disease 2019 (COVID-19) infectivity and death rates has revealed, in many countries around the world, a typical oscillatory pattern with a 7-day (circaseptan) period. Additionally, in some countries, 3.5-day (hemicircaseptan) and 14-day periodicities have also been observed. Interestingly, the 7-day infectivity and death rate oscillations are almost in phase, showing local maxima on Thursdays/Fridays and local minima on Sundays/Mondays. These observations are in stark contrast to a known pattern correlating the death rate with the reduced medical staff in hospitals on the weekends...

OBJECTIVES: To study circadian rhythm aspects, national holidays, and major sports events as triggers of myocardial infarction. DESIGN: Retrospective observational study using the nationwide coronary care unit registry, SWEDEHEART. SETTING: Sweden. PARTICIPANTS: 283 014 cases of myocardial infarction reported to SWEDEHEART between 1998 and 2013. Symptom onset date was documented for all cases, and time to the nearest minute for 88%...

BACKGROUND: Epilepsy has long been suspected to be governed by cyclic rhythms, with seizure rates rising and falling periodically over weeks, months, or even years. The very long scales of seizure patterns seem to defy natural explanation and have sometimes been attributed to hormonal cycles or environmental factors. This study aimed to quantify the strength and prevalence of seizure cycles at multiple temporal scales across a large cohort of people with epilepsy. METHODS: This retrospective cohort study used the two most comprehensive databases of human seizures (SeizureTracker [USA] and NeuroVista [Melbourne, VIC, Australia]) and analytic techniques from circular statistics to analyse patients with epilepsy for the presence and frequency of multitemporal cycles of seizure activity...

Background: Previous analyses of Google search queries identified circaseptan (weekly) rhythms in smoking cessation information seeking, with Google searches for "quit" and "smoking" peaking early in the week. Similar patterns were observed for smoking cessation treatment seeking, such as calls to quitlines. These findings suggest that smoking cessation behaviors may have a weekly rhythm that could be leveraged to improve smoking cessation efforts. Aims: To assess whether weekly enrollment and usage patterns exist for an Internet smoking cessation intervention...

The occurrence of cardiovascular events shows a different distribution during the week, with many studies reporting a Monday peak, possibly related to the role of stress associated with commencing weekly activities. Furthermore, a higher mortality has been observed among patients hospitalized for cardiovascular and other disorders on weekends, a phenomenon known as "weekend effect." Such effect may be explained by a higher level of disease severity among patients admitted over the weekend, and/or by a poorer quality of care associated with shortage of staff, lower experience of personnel, and limited availability of therapeutic and diagnostic procedures...

Striae periodicity refers to the number of cross-striations between successive lines of Retzius in tooth enamel. A regular time dependency of striae periodicity, known as the circaseptan interval, has been proposed. Previous studies on striae periodicity have been carried out on both modern and early humans given its potential applications in forensic age estimations and anthropology. Nevertheless, research comparing striae periodicities across gender groups and populations in different geographical locations, particularly in Asia, is lacking...

Daily diary and other intensive longitudinal methods are increasingly being used to investigate fluctuations in psychological and behavioral processes. To inform the development of this methodology, we sought to explore predictors of and patterns in diary compliance and behavioral reports. We used multilevel modeling to analyze data from an online daily diary study of 371 gay and bisexual men focused on sexual behavior and substance use. We found that greater education and older age as well as lower frequency of substance use were associated with higher compliance...

Sodium balance is achieved within a matter of days and everything that enters should come out; sodium stores are of questionable relevance and sodium accumulation is accompanied by weight gain. Careful balance studies oftentimes conflicted with this view, and long-term studies suggested that total body sodium (TBNa) fluctuates independent of intake or body weight. We recently performed the opposite experiment in that we fixed sodium intake for weeks at three levels of sodium intake and collected all urine made...

Thoracic impedance (TI) denotes the electrical resistance that is measured between the right ventricular lead and the can of an implantable cardioverter-defibrillator. It is used in medical diagnostics for fluid load monitoring in heart failure patients. We analysed TI for diurnal and weekly components that go along with the recurrent patterns of daily life.TI was measured in 53 patients over 280 d each with a resolution of 1 h. Information about the patients' professional occupation and typical sleeping rhythm was sought...

IgY is the functional equivalent of mammalian IgG found in birds, reptiles and amphibians. Many of its biological aspects have been explored with different approaches. In order to evaluate the rhythmicity of serum and yolk IgY, four chickens were examined and reared under the same conditions. To monitor biological oscillations of IgY in yolk and serum, the eggs and blood samples were collected over a 60 day period and the rhythm of yolk and serum IgY was determined by direct-ELISA. Results indicated that, there is a significant circaseptan rhythm in yolk IgY and circaquattran rhythm in serum IgY...

There are three common periodic intervals in the life of each human being from time immemorial: the day, the week and the year. The first one is given by the Earth´s rotation, the latter one by its revolution around the Sun. These both do have clear biomedical counterparts. The 7-day week, basically linguistically "period of change" (or a similar period, e.g.10 days in Egypt or 8 days in Etrutria) was obviously originally considered mainly as a product of a societal agreement. Two groups of Czechoslovak clinicians-scientists, however, noted in forties of the XXth century an approximately week period in human laboratory data, after similar attempts abroad a few years earlier...

BACKGROUND: Biological clocks govern numerous aspects of human health, including weekly clocks-called circaseptan rhythms-that typically include early-week spikes for many illnesses. PURPOSE: To determine whether contemplations for healthy behaviors also follow circaseptan rhythms. METHODS: We assessed healthy contemplations by monitoring Google search queries (2005-2012) in the U.S. that included the word healthy and were Google classified as health-related (e...

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Current teaching states that when sodium intake is increased from low to high levels, total-body sodium (TBNa) and water increase until daily sodium excretion again equals intake. When sodium intake is reduced, sodium excretion briefly exceeds intake until the excess TBNa and water are eliminated, at which point sodium excretion again equals intake. However, careful balance studies oftentimes conflict with this view and long-term studies suggest that TBNa fluctuates independent of intake or body weight. We recently performed the opposite experiment in that we fixed sodium intake for several weeks at three levels of sodium intake and collected all urine made...

The steady-state concept of Na(+) homeostasis, based on short-term investigations of responses to high salt intake, maintains that dietary Na(+) is rapidly eliminated into urine, thereby achieving constant total-body Na(+) and water content. We introduced the reverse experimental approach by fixing salt intake of men participating in space flight simulations at 12 g, 9 g, and 6 g/day for months and tested for the predicted constancy in urinary excretion and total-body Na(+) content. At constant salt intake, daily Na(+) excretion exhibited aldosterone-dependent, weekly (circaseptan) rhythms, resulting in periodic Na(+) storage...

OBJECTIVE: The present study analyzed epidemiological data for patients with subarachnoid hemorrhage (SAH) in a subtropical region of Japan that is the most frequently affected by typhoons. PATIENTS AND METHODS: The medical records of hospitalized patients who had been diagnosed as having SAH at Okinawa Prefectural Yaeyama Hospital during a 13-year period were reviewed. Demographic and epidemiological data including date and time of onset and activity at onset and clinical data were collected...