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Diurnal variation

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https://www.readbyqxmd.com/read/28209805/effects-of-photophase-illuminance-on-locomotor-activity-urine-production-and-urinary-6-sulfatoxymelatonin-in-nocturnal-and-diurnal-south-african-rodents
#1
Ingrid van der Merwe, Maria K Oosthuizen, Andre Ganswindt, Abraham Haim, Nigel C Bennett
Effects of photophase illuminance (1, 10, 100 and 330 lux of white incandescent lighting) on daily rhythms of locomotor activity, urine production and 6-sulfatoxymelatonin (6-SMT; 10 lux vs. 330 lux) were studied in nocturnal Namaqua rock mice (Micaelamys namaquensis) and diurnal four striped field mice (Rhabdomys pumilio). Micaelamys namaquensis was consistently nocturnal (∼90-94% nocturnal activity), whereas considerable individual variation marked activity profiles in R. pumilio, but with activity mostly pronounced around twilight (∼55-66% diurnal activity)...
February 16, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28202701/chronobiology-differs-between-men-and-women-with-cluster-headache-clinical-phenotype-does-not
#2
Nunu Lund, Mads Barloese, Anja Petersen, Bryan Haddock, Rigmor Jensen
OBJECTIVE: To describe differences between the sexes in the phenotype of cluster headache (CH) in a large, well-characterized clinical CH population. METHODS: Patients from the Danish CH survey aged 18-65 years, diagnosed with CH according to International Classification of Headache Disorders, second edition, completed questionnaires and structured interviews. RESULTS: A total of 351 patients with CH participated, with a male:female ratio of 2:1...
February 15, 2017: Neurology
https://www.readbyqxmd.com/read/28202598/early-flowering-3-redundancy-fine-tunes-photoperiod-sensitivity
#3
Andrew J S Rubenach, Valerie Fg Hecht, Jacqueline K Vander Schoor, Lim Chee Liew, Gregoire Aubert, Judith Burstin, James L Weller
Three pea loci controlling photoperiod sensitivity, HIGH RESPONSE (HR), DIE NEUTRALIS (DNE) and STERILE NODES (SN) have recently been shown to correspond to orthologs of Arabidopsis circadian clock genes EARLY FLOWERING3 (ELF3), ELF4, and LUX ARRHYTHMO, respectively. A fourth pea locus, PHOTOPERIOD (PPD), also contributes to the photoperiod response in a similar manner to SN and DNE, and recessive ppd mutants on a spring-flowering hr mutant background show early, photoperiod-insensitive flowering. However, the molecular identity of PPD has so far remained elusive...
February 15, 2017: Plant Physiology
https://www.readbyqxmd.com/read/28202268/three-dimensional-investigation-of-ozone-pollution-in-the-lower-troposphere-using-an-unmanned-aerial-vehicle-platform
#4
Xiao-Bing Li, Dong-Sheng Wang, Qing-Chang Lu, Zhong-Ren Peng, Si-Jia Lu, Bai Li, Chao Li
Potential utilities of instrumented lightweight unmanned aerial vehicles (UAVs) to quickly characterize tropospheric ozone pollution and meteorological factors including air temperature and relative humidity at three-dimensional scales are highlighted in this study. Both vertical and horizontal variations of ozone within the 1000 m lower troposphere at a local area of 4 × 4 km(2) are investigated during summer and autumn times. Results from field measurements show that the UAV platform has a sufficient reliability and precision in capturing spatiotemporal variations of ozone and meteorological factors...
February 12, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28199858/associations-between-hippocampal-morphology-diffusion-characteristics-and-salivary-cortisol-in-older-men
#5
Simon R Cox, Maria Del Carmen Valdés Hernández, Jaeil Kim, Natalie A Royle, Sarah E MacPherson, Karen J Ferguson, Susana Muñoz Maniega, Devasuda Anblagan, Benjamin S Aribisala, Mark E Bastin, Jinah Park, John M Starr, Ian J Deary, Alasdair M J MacLullich, Joanna M Wardlaw
High, unabated glucocorticoid (GC) levels are thought to selectively damage certain tissue types. The hippocampus is thought to be particularly susceptible to such effects, and though findings from animal models and human patients provide some support for this hypothesis, evidence for associations between elevated GCs and lower hippocampal volumes in older age (when GC levels are at greater risk of dysregulation) is inconclusive. To address the possibility that the effects of GCs in non-pathological ageing may be too subtle for gross volumetry to reliably detect, we analyse associations between salivary cortisol (diurnal and reactive measures), hippocampal morphology and diffusion characteristics in 88 males, aged ∼73 years...
January 27, 2017: Psychoneuroendocrinology
https://www.readbyqxmd.com/read/28192738/temporal-variations-in-water-quality-in-a-brackish-tidal-pond-implications-for-governing-processes-and-management-strategies
#6
Wenhui Cui, Ting Fong May Chui
Brackish tidal ponds have been constructed along coastal areas in many parts of the world for aquaculture, including some Ramsar Sites. Such ponds are considered a sustainable, wise use of wetlands if managed properly, but they can also pose serious environmental problems if mismanaged. To understand the governing processes and to promote sustainable management strategies, this study examines the different temporal variations in water quality parameters in a brackish tidal pond located within the wetland complex of the Mai Po Ramsar Site in Hong Kong, China...
February 10, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28188549/characteristics-and-source-apportionment-of-black-carbon-aerosols-over-an-urban-site
#7
T A Rajesh, S Ramachandran
Aethalometer based source apportionment model using the measured aerosol absorption coefficients at different wavelengths is used to apportion the contribution of fossil fuel and wood burning sources to the total black carbon (BC) mass concentration. Temporal and seasonal variabilities in BC mass concentrations, equivalent BC from fossil fuel (BC f f ), and wood burning (BC w b ) are investigated over an urban location in western India during January 2014 to December 2015. BC, BC f f , and BC w b mass concentrations exhibit strong diurnal variation and are mainly influenced by atmospheric dynamics...
February 10, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28188231/diurnal-and-long-term-variation-in-plasma-concentrations-and-renal-clearances-of-circulating-markers-of-kidney-proximal-tubular-secretion
#8
Matthew B Rivara, Leila R Zelnick, Andrew N Hoofnagle, Rick Newitt, Russell P Tracy, Mario Kratz, David S Weigle, Bryan R Kestenbaum
BACKGROUND: The renal proximal tubule is essential for removing organic solutes and exogenous medications from the circulation. We evaluated diurnal, prandial, and long-term biological variation of 4 candidate endogenous markers of proximal tubular secretion. METHODS: We used LC-MS to measure plasma and urine concentrations of hippurate (HA), cinnamoylglycine (CMG), indoxyl sulfate (IS), and p-cresol sulfate (PCS) in 25 healthy adults. We measured plasma concentrations of secreted solutes at 13 time points over a 24-h period, and again after 2 weeks and 14 weeks of follow-up...
February 10, 2017: Clinical Chemistry
https://www.readbyqxmd.com/read/28184234/exploring-diurnal-variation-using-piecewise-linear-splines-an-example-using-blood-pressure
#9
Jamie M Madden, Xia Li, Patricia M Kearney, Kate Tilling, Anthony P Fitzgerald
BACKGROUND: There are many examples of physiological processes that follow a circadian cycle and researchers are interested in alternative methods to illustrate and quantify this diurnal variation. Circadian blood pressure (BP) deserves additional attention given uncertainty relating to the prognostic significance of BP variability in relation to cardiovascular disease. However, the majority of studies exploring variability in ambulatory blood pressure monitoring (ABPM) collapse the data into single readings ignoring the temporal nature of the data...
2017: Emerging Themes in Epidemiology
https://www.readbyqxmd.com/read/28159659/day-night-expression-of-mt1-and-mt2-receptors-in-hypothalamic-nuclei-of-the-primate-sapajus-apella
#10
Luciana Pinato, Dayane Ramos, Alessandre Hataka, Patricia S Rossignoli, Marcos Donisete Granado, Marina Cardoso Mazzetto, Leila M G Campos
Melatonin is involved in the temporal organization of several physiological and behavioral events, controlled by hypothalamic nuclei, like sleep, feeding, reproduction and metabolic modulation and acts through two types of high-affinity G protein-coupled membrane receptors: MT1 and MT2. This study aimed to investigate the expression of MT1 and MT2 receptors proteins in four hypothalamic nuclei, i.e., SCN, supraoptic (SON), paraventricular (PVN) and anteroventral periventricular nuclei (AVPV), of the diurnal primate Sapajus apella using immunohistochemistry...
January 31, 2017: Journal of Chemical Neuroanatomy
https://www.readbyqxmd.com/read/28153404/surface-ozone-characterization-at-larsemann-hills-and-maitri-antarctica
#11
Kaushar Ali, D K Trivedi, S K Sahu
Data are analyzed in terms of daily average ozone, its diurnal variation and its relation with meteorological parameters like dry bulb temperature (T), wet bulb temperature (Tw), atmospheric pressure and wind speed based on measurement of these parameters at two Indian Antarctic stations (Larsemann Hills, and Maitri) during 28th Indian Scientific Expedition of Antarctica (ISEA) organized during Antarctic summer of the year 2008-09. The work has been carried out to investigate summer time ozone level and its day-to-day and diurnal variability at these coastal locations and to highlight possible mechanism of ozone production and destruction...
January 30, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28151944/diurnal-variation-and-twenty-four-hour-sleep-deprivation-do-not-alter-supine-heart-rate-variability-in-healthy-male-young-adults
#12
Daniel S Quintana, Torbjørn Elvsåshagen, Nathalia Zak, Linn B Norbom, Per Ø Pedersen, Sophia H Quraishi, Atle Bjørnerud, Ulrik F Malt, Inge R Groote, Tobias Kaufmann, Ole A Andreassen, Lars T Westlye
Heart rate variability (HRV) has become an increasingly popular index of cardiac autonomic control in the biobehavioral sciences due to its relationship with mental illness and cognitive traits. However, the intraindividual stability of HRV in response to sleep and diurnal disturbances, which are commonly reported in mental illness, and its relationship with executive function are not well understood. Here, in 40 healthy adult males we calculated high frequency HRV-an index of parasympathetic nervous system (PNS) activity-using pulse oximetry during brain imaging, and assessed attentional and executive function performance in a subsequent behavioral test session at three time points: morning, evening, and the following morning...
2017: PloS One
https://www.readbyqxmd.com/read/28149522/incorporating-periodic-variability-in-hidden-markov-models-for-animal-movement
#13
Michael Li, Benjamin M Bolker
BACKGROUND: Clustering time-series data into discrete groups can improve prediction and provide insight into the nature of underlying, unobservable states of the system. However, temporal variation in probabilities of group occupancy, or the rates at which individuals move between groups, can obscure such signals. We use finite mixture and hidden Markov models (HMMs), two standard clustering techniques, to model long-term hourly movement data from Florida panthers (Puma concolor coryi)...
2017: Movement Ecology
https://www.readbyqxmd.com/read/28139325/characterization-of-black-carbon-in-an-urban-rural-fringe-area-of-beijing
#14
Dongsheng Ji, Liang Li, Bo Pang, Peng Xue, Lili Wang, Yunfei Wu, Hongliang Zhang, Yuesi Wang
Measuring black carbon (BC) is critical to understand the impact of combustion aerosols on air quality and climate change. In this study, BC was measured in 2014 at a unique community formed with rapid economic development and urbanization in an urban-rural fringe area of Beijing. Hourly BC concentrations were 0.1-33.5 μg/m(3) with the annual average of 4.4 ± 3.7 μg/m(3). BC concentrations had clear diurnal, weekly, and seasonal variations, and were closely related with atmospheric visibility. The absorption coefficient of aerosols increased while its contribution to extinction coefficient decreased with the enhancement of PM2...
January 27, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28134660/muscle-strength-but-not-muscle-oxidative-capacity-varies-between-the-morning-and-the-afternoon-in-patients-with-multiple-sclerosis-a-pilot-study
#15
Inez Wens, Dominique Hansen
Despite frequent muscle strength or muscle oxidative capacity (based on exercise-onset oxygen uptake [VO2] kinetics) assessments in patients with multiple sclerosis, the impact of time of day on these parameters is often not taken into account. Based on observations in healthy subjects, it remains to be studied whether muscle strength, and/or exercise-onset VO2 kinetics, varies between the morning and the afternoon in patients with multiple sclerosis. In this prospective observational pilot study, walking capacity, exercise-onset VO2 kinetics, isometric knee extension/flexion strength (dynamometry), and self-reported fatigue were measured in 11 patients with multiple sclerosis (age, 51...
January 27, 2017: American Journal of Physical Medicine & Rehabilitation
https://www.readbyqxmd.com/read/28130736/diurnal-variation-of-circulating-microvesicles-is-associated-with-the-severity-of-obstructive-sleep-apnoea
#16
András Bikov, László Kunos, Éva Pállinger, Zsófia Lázár, Adrián Kis, Gábor Horváth, György Losonczy, Zsolt István Komlósi
PURPOSE: Microvesicles (MVs) have been implicated in the pathomechanism of obstructive sleep apnoea (OSA); however, the results are inconsistent, possibly due to an unrevealed temporal variation in circulating MV levels. We aimed to investigate the diurnal changes of MV fractions in OSA. METHODS: Peripheral blood was taken from 18 patients with OSA and 9 healthy subjects at different time points (11:00, 17:00, 21:00, 01:30 and 06:00). Samplings were repeated in nine OSA patients after 2 months of continuous positive airway pressure (CPAP) therapy...
January 27, 2017: Sleep & Breathing, Schlaf & Atmung
https://www.readbyqxmd.com/read/28129406/diurnal-and-seasonal-variations-in-the-net-ecosystem-co2-exchange-of-a-pasture-in-the-three-river-source-region-of-the-qinghai-tibetan-plateau
#17
Bin Wang, Haiyan Jin, Qi Li, Dongdong Chen, Liang Zhao, Yanhong Tang, Tomomichi Kato, Song Gu
Carbon dioxide (CO2) exchange between the atmosphere and grassland ecosystems is very important for the global carbon balance. To assess the CO2 flux and its relationship to environmental factors, the eddy covariance method was used to evaluate the diurnal cycle and seasonal pattern of the net ecosystem CO2 exchange (NEE) of a cultivated pasture in the Three-River Source Region (TRSR) on the Qinghai-Tibetan Plateau from January 1 to December 31, 2008. The diurnal variations in the NEE and ecosystem respiration (Re) during the growing season exhibited single-peak patterns, the maximum and minimum CO2 uptake observed during the noon hours and night; and the maximum and minimum Re took place in the afternoon and early morning, respectively...
2017: PloS One
https://www.readbyqxmd.com/read/28129251/effects-of-the-glucagon-like-peptide-1-receptor-agonist-liraglutide-on-24-h-ambulatory-blood-pressure-in-patients-with-type-2-diabetes-and-stable-coronary-artery-disease-a-randomized-double-blind-placebo-controlled-crossover-study
#18
Preman Kumarathurai, Christian Anholm, Andreas Fabricius-Bjerre, Olav W Nielsen, Ole Kristiansen, Sten Madsbad, Steen B Haugaard, Ahmad Sajadieh
OBJECTIVE: The glucagon-like peptide-1 receptor agonist liraglutide has been shown to reduce blood pressure (BP) in clinical trials using office BP measurements. However, the effects of liraglutide on 24-h BP and on the diurnal variation in BP have not been explored sufficiently. METHODS: Forty-one patients with type 2 diabetes and stable coronary artery disease were randomized to receive liraglutide or placebo to a backbone therapy of metformin in this double-blind, placebo-controlled 12 along with 12 weeks crossover study...
January 27, 2017: Journal of Hypertension
https://www.readbyqxmd.com/read/28123179/diurnal-variation-of-urinary-sodium-to-potassium-ratio-in-free-living-japanese-individuals
#19
Toshiyuki Iwahori, Hirotsugu Ueshima, Sayuki Torii, Yoshino Saito, Keiko Kondo, Sachiko Tanaka-Mizuno, Hisatomi Arima, Katsuyuki Miura
High sodium-to-potassium ratios are associated with elevated blood pressure levels and an increased risk of cardiovascular diseases. We aimed to determine whether urinary sodium-to-potassium ratios fluctuate diurnally during the day to understand measured values of casual urinary sodium-to-potassium ratios. A total of 13,277 casual urine specimens were collected under free-living conditions from 122 Japanese normotensive and hypertensive individuals. Participants collected all casual urine samples in aliquot tubes, reported urine volumes and the time at each voiding for 10-22 days...
January 26, 2017: Hypertension Research: Official Journal of the Japanese Society of Hypertension
https://www.readbyqxmd.com/read/28120161/what-is-the-best-blood-sampling-time-for-metabolic-control-of-phenylalanine-and-tyrosine-concentrations-in-tyrosinemia-type-1-patients
#20
Esther van Dam, Anne Daly, Gineke Venema-Liefaard, Margreet van Rijn, Terry G J Derks, Patrick J McKiernan, M Rebecca Heiner-Fokkema, Anita MacDonald, Francjan J van Spronsen
BACKGROUND: Treatment of hereditary tyrosinemia type 1 with nitisinone and phenylalanine and tyrosine restricted diet has largely improved outcome, but the best blood sampling time for assessment of metabolic control is not known. AIM: To study diurnal and day-to-day variation of phenylalanine and tyrosine concentrations in tyrosinemia type 1 patients. METHODS: Eighteen tyrosinemia type 1 patients aged >1 year (median age 7.9 years; range 1...
January 25, 2017: JIMD Reports
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