Journal of Circadian Rhythms最新文献

{"title":"Circadian Pattern of Melatonin MT1 and MT2 Receptor Localization in the Rat Suprachiasmatic Nucleus.","authors":"Nermien E Waly,&nbsp;Richard Hallworth","doi":"10.5334/jcr.ab","DOIUrl":"https://doi.org/10.5334/jcr.ab","url":null,"abstract":"<p><p>The suprachiasmatic nucleus (SCN) is the master circadian pacemaker. The pineal hormone melatonin is involved in the regulation of circadian phase. As a part of the circadian system, its synthesis and secretion is under SCN control. On the other hand, melatonin feeds back on the SCN to regulate its function. Melatonin has two specific windows of time at which it regulates SCN function, namely dusk and dawn. It has been suggested that melatonin exerts its effect on the SCN during that specific window of time via one or both of its specific receptors, MT1 or MT2. The hypothesis that the density of these receptors varies across the circadian cycle was tested. Using immunohistochemistry with receptor-specific antibodies, the localization and distribution of melatonin receptors MT1 and MT2 was studied in the SCN at different Zeitgeber times (ZT): ZT 11-13 (dusk), 23-01 (dawn), 5-7 (mid-day), and 17-19 (midnight). Our results show that MT1 receptor density significantly increased at dusk relative to dawn and midnight (p<0.01 and p<0.001 respectively). Although MT1 receptors were widespread in the SCN and parts of the optic chiasm at dusk, they were restricted to the SCN during the mid-day period. MT2 receptors were not detected in the SCN. Thus, we find that melatonin receptor MT1 density and distribution varies with circadian time. This creates a time window during which melatonin can affect the operation of the SCN. We also find that melatonin regulates SCN function via MT1 receptors with a minimal role for MT2. </p>","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":"13 ","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2015-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4831275/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34423891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prevalence of Insomnia and Sleep Patterns among Liver Cirrhosis Patients","authors":"H. Al-Jahdali, A. Al Enezi, Ahmed E. Anwar, A. Al-Harbi, S. Baharoon, A. Aljumah, A. Shimemeri, K. Abdullah","doi":"10.5334/jcr.aa","DOIUrl":"https://doi.org/10.5334/jcr.aa","url":null,"abstract":"Background: Few studies are available regarding the prevalence of sleep disturbance in cirrhotic patients without overt hepatic encephalopathy. This study aimed to assess the prevalence of insomnia in stable liver cirrhosis patients who are attending the outpatient clinics at King Abdulaziz Medical City, Riyadh (KAMC-KFNGH). Methods: A cross-sectional study enrolled 200 stable patients with confirmed liver cirrhosis. We used the ICSD-2 definition to assess the prevalence of insomnia. We also collected information about sleep patterns, demographic data, the underlying cause of liver cirrhosis and the severity of liver cirrhosis using Child-Pugh scores (CTP). Results: The mean age was 58.9 (SD ± 12.2) years. Hepatitis C was the most common (60.2%) cause of liver cirrhosis among respondents. The prevalence of insomnia was 42% (84/200). Univarite analysis shows association between coffee intake and the presence of insomnia (56.9% vs. 35.9%, p-value = 0.006). The prevalence of insomnia was higher in hepatitis C (51.7%) compared to hepatitis B (36.8%) and other hepatitis (15%), p-value = 0.001. There was a significant relationship between severity of liver cirrhosis (CTP-A, CTP-C, CTP-B) and prevalence of insomnia: 55%, 36.1% and 32.1% respectively, p-value = 0.009. Insomniac patients were significantly older than non-insomniac (61.6 ± 12.0 vs. 57.0 ± 12.0 years, p = 0.008). Results from the multivariate stepwise analysis showed coffee intake (OR=2.7), hepatitis C (OR = 7.2), CTP-A (OR = 1.9), excessive daytime sleepiness (OR = 5.3) and short sleep duration (OR = 5.7) were the most strongly associated with the presence of insomnia. Conclusion: Our study showed a high prevalence of insomnia in patients with liver cirrhosis.","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70675045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Daily blood feeding rhythms of laboratory-reared North American Culex pipiens.","authors":"Megan L Fritz,&nbsp;Edward D Walker,&nbsp;Aaron J Yunker,&nbsp;Ian Dworkin","doi":"10.1186/1740-3391-12-1","DOIUrl":"https://doi.org/10.1186/1740-3391-12-1","url":null,"abstract":"<p><strong>Background: </strong>Blood feeding by free-living insect vectors of disease is rhythmic and can be used to predict when infectious bites will occur. These daily rhythms can also be targeted by control measures, as in insecticide-treated nets. Culex pipiens form pipiens and C.p. f. molestus are two members of the Culex pipiens assemblage and vectors of West Nile Virus throughout North America. Although Culex species vector human pathogens and parasites, the daily blood feeding rhythms of C.p. f. molestus, to our knowledge, have not been studied. We described and compared the daily blood feeding rhythms of three laboratory-reared populations of Culex pipiens, one of which has confirmed molestus ancestry. We also examined the plasticity of blood feeding time for these three populations.</p><p><strong>Results: </strong>For most (>70%) C.p. f. pipiens and C.p. f. molestus collected from metropolitan Chicago, IL, blood feeding took place during scotophase. Peak blood feeding occurred in mid-scotophase, 3-6 hours after lights off. For C.p. f. pipiens originating from Pennsylvania, most mosquitoes (> 90%) blood fed during late photophase and early scotophase. C.p. f. molestus denied a blood meal during scotophase were less likely to blood feed during early photophase (< 20%) than were C.p. f. pipiens from Chicago (> 50%). C.p. f. pipiens from Pennsylvania were capable of feeding readily at any hour of photo- or scotophase.</p><p><strong>Conclusions: </strong>Daily blood feeding rhythms of C.p. f. molestus are similar to those of C.p. f. pipiens, particularly when populations originate from the same geographic region. However, the timing of blood feeding is more flexible for C.p. f. pipiens populations relative to C.p. f. molestus.</p>","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":"12 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2014-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1740-3391-12-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"32052182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Daily cycling of nitric oxide synthase (NOS) in the hippocampus of pigeons (C. livia).","authors":"Aline V Machado-Nils,&nbsp;Larissa Om de Faria,&nbsp;André S Vieira,&nbsp;Simone A Teixeira,&nbsp;Marcelo N Muscará,&nbsp;Elenice Am Ferrari","doi":"10.1186/1740-3391-11-12","DOIUrl":"https://doi.org/10.1186/1740-3391-11-12","url":null,"abstract":"<p><strong>Background: </strong>Nitric oxide synthase (NOS) is essential for the synthesis of nitric oxide (NO), a non-conventional neurotransmitter with an important role in synaptic plasticity underlying processes of hippocampus-dependent memory and in the regulation of biological clocks and circadian rhythms. Many studies have shown that both the NOS cytosolic protein content and its enzymatic activity present a circadian variation in different regions of the rodent brain, including the hippocampus. The present study investigated the daily variation of NOS enzymatic activity and the cytosolic content of nNOS in the hippocampus of pigeons.</p><p><strong>Results: </strong>Adult pigeons kept under a skeleton photoperiod were assigned to six different groups. Homogenates of the hippocampus obtained at six different times-of-day were used for NOS analyses. Both iNOS activity and nNOS cytosolic protein concentrations were highest during the subjective light phase and lowest in the subjective dark phase of the circadian period. ANOVA showed significant time differences for iNOS enzymatic activity (p < 0.05) and for nNOS protein content (p < 0.05) in the hippocampus. A significant daily rhythm for both iNOS and nNOS was confirmed by analysis with the Cosinor method (p < 0.05). The present findings indicate that the enzymatic activity of iNOS and content of nNOS protein in the hippocampus of pigeons exhibit a daily rhythm, with acrophase values occurring during the behavioral activity phase.</p><p><strong>Conclusions: </strong>The data corroborate the reports on circadian variation of NOS in the mammalian hippocampus and can be considered indicative of a dynamic interaction between hippocampus-dependent processes and circadian clock mechanisms.</p>","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":" ","pages":"12"},"PeriodicalIF":0.0,"publicationDate":"2013-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1740-3391-11-12","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40280867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synaptophysin is involved in resetting of the mammalian circadian clock.","authors":"Marie Aramendy,&nbsp;Sascha Seibert,&nbsp;Philipp Treppmann,&nbsp;Karin Richter,&nbsp;Gudrun Ahnert-Hilger,&nbsp;Urs Albrecht","doi":"10.1186/1740-3391-11-11","DOIUrl":"https://doi.org/10.1186/1740-3391-11-11","url":null,"abstract":"<p><strong>Background: </strong>Mammals can adapt to changing light/dark conditions by advancing or delaying their circadian clock phase. Light pulses evoke changes in gene expression and neuronal activity in the suprachiasmatic nuclei (SCN), the central pacemaker of the circadian system. Alterations in neuronal activity are partially mediated by changes in synaptic vesicle (SV) fusion at the presynaptic membrane, which modulates release of neurotransmitters.</p><p><strong>Methods: </strong>Male synaptophysin (Syp) knock-out and littermate control wild type mice were tested in an Aschoff type I resetting paradigm. Additionally, gene expression of cFos, Per1 and Per2 was assessed in the SCN. Finally, complexes between the synaptic vesicle proteins Syp and synaptobrevin (Syb) were studied in order to correlate behavior with protein complexes at synaptic vesicles.</p><p><strong>Results: </strong>Here we show that mice lacking Syp, a modulator of neurotransmitter release, are defective in delaying clock phase. In contrast, clock phase advances as well as clock period are normal in Syp-/- knock-out mice. This correlates with the formation of Syp/Syb complexes.</p><p><strong>Conclusions: </strong>Our findings suggest that Syp is involved specifically in the response to a nocturnal light pulse occurring in the early night. It appears that the SV component Syp is critically involved in the delay portion of the resetting mechanism of the circadian clock.</p>","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":"11 1","pages":"11"},"PeriodicalIF":0.0,"publicationDate":"2013-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1740-3391-11-11","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31773042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An out-of-lab trial: a case example for the effect of intensive exercise on rhythms of human clock gene expression.","authors":"Akihiko Okamoto,&nbsp;Takuro Yamamoto,&nbsp;Ritsuko Matsumura,&nbsp;Koichi Node,&nbsp;Makoto Akashi","doi":"10.1186/1740-3391-11-10","DOIUrl":"https://doi.org/10.1186/1740-3391-11-10","url":null,"abstract":"<p><strong>Background: </strong>Although out-of-lab investigation of the human circadian clock at the clock gene expression level remains difficult, a recent method using hair follicle cells might be useful. While exercise may function as an entrainment cue for circadian rhythms, it remains unclear whether exercise affects human circadian clock gene expression.</p><p><strong>Methods: </strong>Efforts to observe apparent effects of exercise on clock gene expression require that several specific conditions be met: intense exercise should be habitually performed at a relatively uncommon time of day over an extended period; and any relative phase shift thereby observed should be validated by comparison of exercise and no-exercise periods. Wake-up and meal times should be kept almost constant over the experimental period. The present study was conducted using a professional fighter who met these strict criteria as subject. Facial hair samples were collected at 4-h intervals around the clock to ascertain rhythms of clock gene expression.</p><p><strong>Results: </strong>During a period in which nighttime training (from 20:00 to 22:00) was habitually performed, circadian clock gene expression was phase-delayed by 2 to 4 h compared with that during a no-exercise period. Maximum level and circadian amplitude of clock gene expression were not affected by the nighttime training.</p><p><strong>Conclusion: </strong>Our trial observations illustrate the possibility that heavy physical exercise might strongly affect the circadian phase of clock gene expression. Exercise might be therefore effective for the clinical care of circadian disorders. The results also suggest that athletes may require careful scheduling of heavy physical exercise to maintain normal circadian phase and ensure optimal athletic performance.</p>","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":"11 1","pages":"10"},"PeriodicalIF":0.0,"publicationDate":"2013-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1740-3391-11-10","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31706777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Circadian behavior of mice deficient in PER1/PML or PER2/PML.","authors":"Takao Miki,&nbsp;Misty Chen-Goodspeed,&nbsp;Zhaoyang Zhao,&nbsp;Cheng Chi Lee","doi":"10.1186/1740-3391-11-9","DOIUrl":"https://doi.org/10.1186/1740-3391-11-9","url":null,"abstract":"<p><strong>Background: </strong>Our recent studies demonstrate that the murine homolog of the human tumor suppressor promyelocytic leukemia (PML) regulates circadian behavior of mice. To further gather insight into PML's contribution to circadian behavior, we generated two strains of mice deficient in one of the two period (Per) genes and the PML gene, with Per1-/-/Pml-/- and Per2-/-/Pml-/- genotypes.</p><p><strong>Results: </strong>Here we report the circadian behavior of these mice based on wheel-running behavioral analysis. In a free-running environment, the Per1-/-/Pml-/- mice maintained circadian rhythm but displayed a significantly shorter period of 22.2 h. In addition, these mice displayed significantly enhanced phase response to a light pulse given at zeitgeber time (ZT) 14 and 22. The Per2-/-/Pml-/- mice lose persistent rhythm when in a free-running environment, as also the case for Per2-/- mice. A transient post-light pulse rhythm seen in the arrhythmic Per2-/- mice was less apparent in Per2-/-/Pml-/- mice. Both the Per1-/-/Pml-/- and Per2-/-/Pml-/- mice displayed a more advanced phase angle of entrainment activity during light-dark cycles than the single gene deficient mice.</p><p><strong>Conclusions: </strong>Beyond merely regulating PER1 and PER2, the current behavioral studies suggest PML has additional roles in mouse circadian behavior.</p>","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":"11 1","pages":"9"},"PeriodicalIF":0.0,"publicationDate":"2013-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1740-3391-11-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31691197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diurnal and nutritional adjustments of intracellular Ca2+ release channels and Ca2+ ATPases associated with restricted feeding schedules in the rat liver.","authors":"Adrián Báez-Ruiz,&nbsp;Karina Cázares-Gómez,&nbsp;Olivia Vázquez-Martínez,&nbsp;Raúl Aguilar-Roblero,&nbsp;Mauricio Díaz-Muñoz","doi":"10.1186/1740-3391-11-8","DOIUrl":"https://doi.org/10.1186/1740-3391-11-8","url":null,"abstract":"<p><strong>Background: </strong>Intracellular calcium is a biochemical messenger that regulates part of the metabolic adaptations in the daily fed-fast cycle. The aim of this study was to characterize the 24-h variations of the liver ryanodine and IP3 receptors (RyR and IP3R) as well as of the endoplasmic-reticulum and plasma-membrane Ca2+-ATPases (SERCA and PMCA) in daytime restricted feeding protocol.</p><p><strong>Methods: </strong>A biochemical and immunohistochemical approach was implemented in this study: specific ligand-binding for RyR and IP3R, enzymatic activity (SERCA and PMCA), and protein levels and zonational hepatic-distribution were determined by immunoblot and immunohistochemistry respectively under conditions of fasting, feeding, and temporal food-restriction.</p><p><strong>Results: </strong>Binding assays and immunoblots for IP3R1 and 2 showed a peak at the light/dark transition in the ad-libitum (AL) group, whereas in the restricted-feeding (RF) group the peak shifted towards the food-access time. In the case of RyR binding experiments, both AL and RF groups showed a modest elevation during the dark period, with the RF rats exhibiting increased binding in response to feeding. The AL group showed 24-h rhythmicity in SERCA level; in contrast, RF group showed a pronounced amplitude elevation and a peak phase-shift during the light-period in SERCA level and activity. The activity of PMCA was constant along day in both groups; PMCA1 levels showed a 24-h rhythmicity in the RF rats (with a peak in the light period), meanwhile PMCA4 protein levels showed rhythmicity in both groups. The fasted condition promoted an increase in IP3R binding and protein level; re-feeding increased the amount of RyR; neither the activity nor expression of SERCA and PMCA protein was affected by fasting-re-feeding conditions. Histochemical experiments showed that the distribution of the Ca2+-handling proteins, between periportal and pericentral zones of the liver, varied with the time of day and the feeding protocol.</p><p><strong>Conclusions: </strong>Our findings show that RF influences mainly the phase and amplitude of hepatic IP3R and SERCA rhythms as well as discrete zonational distribution for RyR, IP3Rs, SERCA, and PMCA within the liver acinus, suggesting that intracellular calcium dynamics could be part of the rheostatic adaptation of the liver due to diurnal meal entrainment/food entrained oscillator expression.</p>","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":"11 1","pages":"8"},"PeriodicalIF":0.0,"publicationDate":"2013-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1740-3391-11-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31671234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methods for serial analysis of long time series in the study of biological rhythms.","authors":"Antoni Díez-Noguera","doi":"10.1186/1740-3391-11-7","DOIUrl":"10.1186/1740-3391-11-7","url":null,"abstract":"<p><p>When one is faced with the analysis of long time series, one often finds that the characteristics of circadian rhythms vary with time throughout the series. To cope with this situation, the whole series can be fragmented into successive sections which are analyzed one after the other, which constitutes a serial analysis. This article discusses serial analysis techniques, beginning with the characteristics that the sections must have and how they can affect the results. After consideration of the effects of some simple filters, different types of serial analysis are discussed systematically according to the variable analyzed or the estimated parameters: scalar magnitudes, angular magnitudes (time or phase), magnitudes related to frequencies (or periods), periodograms, and derived and / or special magnitudes and variables. The use of wavelet analysis and convolutions in long time series is also discussed. In all cases the fundamentals of each method are exposed, jointly with practical considerations and graphic examples. The final section provides information about software available to perform this type of analysis. </p>","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":"11 1","pages":"7"},"PeriodicalIF":0.0,"publicationDate":"2013-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3723718/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31232340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Maximum entropy spectral analysis for circadian rhythms: theory, history and practice.","authors":"Harold B Dowse","doi":"10.1186/1740-3391-11-6","DOIUrl":"https://doi.org/10.1186/1740-3391-11-6","url":null,"abstract":"<p><p>There is an array of numerical techniques available to estimate the period of circadian and other biological rhythms. Criteria for choosing a method include accuracy of period measurement, resolution of signal embedded in noise or of multiple periodicities, and sensitivity to the presence of weak rhythms and robustness in the presence of stochastic noise. Maximum Entropy Spectral Analysis (MESA) has proven itself excellent in all regards. The MESA algorithm fits an autoregressive model to the data and extracts the spectrum from its coefficients. Entropy in this context refers to \"ignorance\" of the data and since this is formally maximized, no unwarranted assumptions are made. Computationally, the coefficients are calculated efficiently by solution of the Yule-Walker equations in an iterative algorithm. MESA is compared here to other common techniques. It is normal to remove high frequency noise from time series using digital filters before analysis. The Butterworth filter is demonstrated here and a danger inherent in multiple filtering passes is discussed. </p>","PeriodicalId":15461,"journal":{"name":"Journal of Circadian Rhythms","volume":"11 1","pages":"6"},"PeriodicalIF":0.0,"publicationDate":"2013-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1186/1740-3391-11-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"31571964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}