51 research outputs found

    Effect of Intensive Training on Mood With No Effect on Brain-Derived Neurotrophic Factor

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    Purpose Monitoring mood state is a useful tool for avoiding non-functional overreaching (NFOR). Brain derived neurotrophic factor (BDNF) is implicated in stress-related mood disorders. The purpose of the present study was to investigate the impact of intensified training-induced mood disturbance on plasma BDNF concentrations at rest and in response to exercise.  Methods Eight cyclists performed 1 week of normal (NT), 1 week of intensified (INT) and 1 week of recovery (REC) training. Fasted blood samples were collected before and after exercise, on day 7 of each training week and were analyzed for plasma BDNF and cortisol concentrations. A 24-item Profile Of Mood State questionnaire was administered on day 7 of each training week and global mood score (GMS) was calculated. Results Time trial performance was impaired during INT (p=0.01) and REC (p=0.02) compared with NT. Basal plasma cortisol (NT=153±16 ng/ml, INT=130±11 ng/ml, REC=150±14 ng/ml) and BDNF (NT=484±122 pg/ml, INT=488±122 pg/ml, REC=383±56 pg/ml) concentrations were similar between training conditions. Likewise, similar exercise-induced increases in cortisol and BDNF concentrations were observed between training conditions. GMS was 32% greater during INTvs.NT (P<0.001). Conclusion Consistent with a state of functional overreaching (FOR), impairments in performance and mood state with INT were restored after one week of REC. These results support evidence that mood changes before plasma BDNF concentrations as a biochemical marker of FOR and that cortisol is not a useful marker for predicting FOR

    Flares, Rotation, Activity Cycles and a Magnetic Star-Planet Interaction Hypothesis for the Far Ultraviolet Emission of GJ 436

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    Variability in the far ultraviolet (FUV) emission produced by stellar activity affects photochemistry and heating in orbiting planetary atmospheres. We present a comprehensive analysis of the FUV variability of GJ 436, a field-age, M2.5V star (Prot≈44P_\mathrm{rot}\approx44 d) orbited by a warm, Neptune-size planet (M≈25 M⊕M \approx 25\ M_\oplus, R≈4.1 R⊕R \approx 4.1\ R_\oplus, Porb≈2.6P_\mathrm{orb}\approx2.6 d). Observations at three epochs from 2012 to 2018 span nearly a full activity cycle, sample two rotations of the star and two orbital periods of the planet, and reveal a multitude of brief flares. Over 2012-2018, the star's 7.75±0.107.75\pm0.10 yr activity cycle produced the largest observed variations, 38±338\pm3% in the summed flux of major FUV emission lines. In 2018, variability due to rotation was 8±28\pm2%. An additional 11±111\pm1% scatter at 10 min cadence, treated as white noise in fits, likely has both instrumental and astrophysical origins. Flares increased time-averaged emission by 15% over the 0.88 d of cumulative exposure, peaking as high as 25×\times quiescence. We interpret these flare values as lower limits given that flares too weak or too infrequent to have been observed likely exist. GJ 436's flare frequency distribution (FFD) at FUV wavelengths is unusual compared to other field-age M dwarfs, exhibiting a statistically-significant dearth of high energy (>4×1028>4\times 10^{28} erg) events that we hypothesize to be the result of a magnetic star-planet interaction (SPI) triggering premature flares. If an SPI is present, GJ 436 b's magnetic field strength must be ≲\lesssim100 G to explain the statistically insignificant increase in orbit-phased FUV emission.Comment: 18 pages, 9 figures, accepted to the Astronomical Journa

    An ultrahot Neptune in the Neptune desert

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    About 1 out of 200 Sun-like stars has a planet with an orbital period shorter than one day: an ultrashort-period planet. All of the previously known ultrashort-period planets are either hot Jupiters, with sizes above 10 Earth radii (R⊕), or apparently rocky planets smaller than 2 R⊕. Such lack of planets of intermediate size (the ‘hot Neptune desert’) has been interpreted as the inability of low-mass planets to retain any hydrogen/helium (H/He) envelope in the face of strong stellar irradiation. Here we report the discovery of an ultrashort-period planet with a radius of 4.6 R⊕ and a mass of 29 M⊕, firmly in the hot Neptune desert. Data from the Transiting Exoplanet Survey Satellite revealed transits of the bright Sun-like star LTT 9779 every 0.79 days. The planet’s mean density is similar to that of Neptune, and according to thermal evolution models, it has a H/He-rich envelope constituting 9.0^(+2.7)_(−2.9)% of the total mass. With an equilibrium temperature around 2,000 K, it is unclear how this ‘ultrahot Neptune’ managed to retain such an envelope. Follow-up observations of the planet’s atmosphere to better understand its origin and physical nature will be facilitated by the star’s brightness (V_(mag) = 9.8)

    PANC Study (Pancreatitis: A National Cohort Study): national cohort study examining the first 30 days from presentation of acute pancreatitis in the UK

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    Abstract Background Acute pancreatitis is a common, yet complex, emergency surgical presentation. Multiple guidelines exist and management can vary significantly. The aim of this first UK, multicentre, prospective cohort study was to assess the variation in management of acute pancreatitis to guide resource planning and optimize treatment. Methods All patients aged greater than or equal to 18 years presenting with acute pancreatitis, as per the Atlanta criteria, from March to April 2021 were eligible for inclusion and followed up for 30 days. Anonymized data were uploaded to a secure electronic database in line with local governance approvals. Results A total of 113 hospitals contributed data on 2580 patients, with an equal sex distribution and a mean age of 57 years. The aetiology was gallstones in 50.6 per cent, with idiopathic the next most common (22.4 per cent). In addition to the 7.6 per cent with a diagnosis of chronic pancreatitis, 20.1 per cent of patients had a previous episode of acute pancreatitis. One in 20 patients were classed as having severe pancreatitis, as per the Atlanta criteria. The overall mortality rate was 2.3 per cent at 30 days, but rose to one in three in the severe group. Predictors of death included male sex, increased age, and frailty; previous acute pancreatitis and gallstones as aetiologies were protective. Smoking status and body mass index did not affect death. Conclusion Most patients presenting with acute pancreatitis have a mild, self-limiting disease. Rates of patients with idiopathic pancreatitis are high. Recurrent attacks of pancreatitis are common, but are likely to have reduced risk of death on subsequent admissions. </jats:sec

    Phylogenetic relationships and tempo of early diversification in Anolis Lizards.

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    Abstract. — We examine phylogenetic relationships among anoles using mitochondrial DNA se-quences from the NADH dehydrogenase subunit 2 gene (ND2) and ve transfer-RNA genes repre-senting 1,455 alignable base positions and 866 phylogenetically informative characters (parsimony criterion). We also present 16 morphological characters for phylogenetic analysis. Our analyses yielded poorly-supported nodes deep in the anole tree but many well-supported nodes for more recent phylogenetic divergences. We test the hypothesis that the major clades of anoles form a hard polytomy and present a general statistical framework for testing hypotheses of simultaneous branching of lineages by using molecular sequence data. Our results suggest that rapid diversi-cation early in the evolutionary history of anoles explains why numerous researchers have had difculty reconstructing well-supported dichotomous phylogenetic trees for anoles. [Anolis; mito-chondrial DNA; parametric bootstrap; permutation test; phylogeny; polytomy.] Anoles are a classic example of adaptive radiation (Jackman et al., 1997), featuring oc-cupation of a great variety of habitats and corresponding diversity in form (Williams, 1983; Losos et al., 1998). Nearly 400 species of anoles are recognized, 140 of which oc

    Data from: Phylogenetic relationships and tempo of early diversification in Anolis lizards

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    We examine phylogenetic relationships among anoles using mitochondrial DNA sequences from the NADH dehydrogenase subunit 2 gene (ND2) and five transfer-RNA genes representing 1,455 alignable base positions and 866 phylogenetically informative characters (parsimony criterion). We also present 16 morphological characters for phylogenetic analysis. Our analyses yielded poorly-supported nodes deep in the anole tree but many well-supported nodes for more recent phylogenetic divergences. We test the hypothesis that the major clades of anoles form a hard polytomy and present a general statistical framework for testing hypothesis of simultaneous branching of lineages by using molecular sequence data. Our results suggest that rapid diversification early in the evolutionary history of anoles explains why numberous researchers have had difficulty reconstruction well-supported dichotomous phylogenetic trees for anoles

    Data from: Phylogenetic relationships and tempo of early diversification in Anolis lizards

    No full text
    We examine phylogenetic relationships among anoles using mitochondrial DNA sequences from the NADH dehydrogenase subunit 2 gene (ND2) and five transfer-RNA genes representing 1,455 alignable base positions and 866 phylogenetically informative characters (parsimony criterion). We also present 16 morphological characters for phylogenetic analysis. Our analyses yielded poorly-supported nodes deep in the anole tree but many well-supported nodes for more recent phylogenetic divergences. We test the hypothesis that the major clades of anoles form a hard polytomy and present a general statistical framework for testing hypothesis of simultaneous branching of lineages by using molecular sequence data. Our results suggest that rapid diversification early in the evolutionary history of anoles explains why numberous researchers have had difficulty reconstruction well-supported dichotomous phylogenetic trees for anoles

    Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise

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    Background: The intake of whey, compared with casein and soy protein intakes, stimulates a greater acute response of muscle protein synthesis (MPS) to protein ingestion in rested and exercised muscle. Objective: We characterized the dose-response relation of postabsorptive rates of myofibrillar MPS to increasing amounts of whey protein at rest and after exercise in resistance-trained, young men. Design: Volunteers (n = 48) consumed a standardized, high-protein (0.54 g/kg body mass) breakfast. Three hours later, a bout of unilateral exercise (8 &times; 10 leg presses and leg extensions; 80% one-repetition maximum) was performed. Volunteers ingested 0, 10, 20, or 40 g whey protein isolate immediately (&sim;10 min) after exercise. Postabsorptive rates of myofibrillar MPS and whole-body rates of phenylalanine oxidation and urea production were measured over a 4-h postdrink period by continuous tracer infusion of labeled [13C6] phenylalanine and [15N2] urea. Results: Myofibrillar MPS (mean &plusmn; SD) increased (P &lt; 0.05) above 0 g whey protein (0.041 &plusmn; 0.015%/h) by 49% and 56% with the ingestion of 20 and 40 g whey protein, respectively, whereas no additional stimulation was observed with 10 g whey protein (P &gt; 0.05). Rates of phenylalanine oxidation and urea production increased with the ingestion of 40 g whey protein. Conclusions: A 20-g dose of whey protein is sufficient for the maximal stimulation of postabsorptive rates of myofibrillar MPS in rested and exercised muscle of &sim;80-kg resistance-trained, young men. A dose of whey protein &gt;20 g stimulates amino acid oxidation and ureagenesis. This trial was registered at http://www.isrctn.org/ as ISRCTN92528122
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