362 research outputs found

    Late Wolstonian and Ipswichian (MIS 6/5e) sediment fill in a limestone sinkhole, Askham Fell, northern England

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    In 2019 a sinkhole (doline) occurred in Late Devensian till above fissured limestone in northern England. Most sediment plugging the fissure was evacuated down into a karstic drainage system. The residual sedimentary fill comprises three main lithofacies, dated using optically stimulated luminescence to between 170.7 ± 40.0 and 56.1 ± 13.5 ka. The earliest date demonstrates fissures were present in the limestone pavement at the time of Marine Isotope Stage (MIS) 6, or shortly thereafter. The fissure filled with fine sand and silt due to surface runoff and aeolian processes probably at the MIS 6 to MIS 5e transition after Wolstonian glacial ice had retreated. The deposits then collapsed into the karst system. Further fine sand and silt deposition occurred during MIS 3; this deposit filled the central cavity surrounded by residual MIS 6/5e deposits. The sequence was capped by till as Late Devensian (MIS 2) ice transgressed the area. Solution fissures in the karst surfaces of northern England may pre-date the Late Devensian glaciation. Moreover, fissures are repositories of pre-Devensian sediment deposits which survived the Late Devensian glaciation and the Ipswichian interglacial. Such sites should provide information on the nature and timing of pre-Devensian glacial–interglacial events and shed light on basal ice conditions and glaciokarst drainage behaviour

    Utilisation of performance markers to establish the effectiveness of cold-water immersion as a recovery modality in elite football.

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    Optimal strategies for recovery following training and competition in elite athletes presents ongoing debate. The effects of cold-water immersion (CWI) compared to passive recovery (PR) though a triad of performance measures after fatiguing exercise within a normal micro-cycle, during mid-competitive training cycle, in elite male footballers were investigated. Twenty-four elite footballers (age 20.58±2.55years; height 179.9±5.6cm; weight 75.7±7.5Kg; body fat 6.2±1.7%) were randomly assigned to CWI or PR following a fatiguing training session. Objective measures included eccentric hamstring strength, isometric adductor strength, hamstring flexibility and skin surface temperature (Tsk). Subjective measures included overall wellbeing. Data were collected at match day+3, immediately post-training, immediately post-intervention and 24hrs post-intervention. Physiological, biomechanical and psychological measures displayed significant main effects for timepoint for eccentric hamstring strength, Tsk, overall wellbeing, sleep, fatigue, stress and group for eccentric hamstring strength, Tsk and sleep (groups combined). Group responses identified significant effects for timepoint for CWI and PR, for eccentric hamstring strength peak force, sleep, fatigue, and muscle soreness for CWI. Significant differences were displayed for eccentric hamstring strength (immediately post-intervention and immediately post-training) for peak force and between CWI and PR eccentric hamstring strength immediately post-intervention. Linear regression for individual analysis demonstrated greater recovery in peak torque and force for CWI. CWI may be useful to ameliorate potential deficits in eccentric hamstring strength that optimise readiness to train/play in elite football settings. Multiple measures and individual analysis of recovery responses provides sports medicine and performance practitioners with direction on the application of modified approaches to recovery strategies, within mid-competitive season training cycles

    Carbonyl[hydrotris(3,5-dimethylpyrazol-1-yl)borato]copper(I) acetonitrile solvate

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    The title compound, [Cu(C15H22BN6)(CO)]·C2H3N, crystallizes as neutral [Tp*Cu(CO)] {[Tp*]- = hydro­tris(3,5-di­methyl­pyrazol-1-yl)­borate} molecular units and non-coordinated aceto­nitrile mol­ecules. The distorted tetrahedral coordination geometry of the copper(I) centre comprises the three N atoms of the [Tp*]- anion [Cu-N 2.033 (2)-2.054 (2) Å] and the C atom of the carbon monoxide mol­ecule [Cu-C 1.785 (4) Å]

    Physiological constraints and energetic costs of diving behaviour in marine mammals : a review of studies using trained Steller sea lions diving in the open ocean

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    The research was funded through a number of sources, including grants provided by the Natural Sciences and Engineering Research Council (Canada) and from the US National Oceanic and Atmospheric Administration to the North Pacific Universities Marine Mammal Research Consortium through the North Pacific Marine Science Foundation.Marine mammals are characterized as having physiological specializations that maximize the use of oxygen stores to prolong time spent under water. However, it has been difficult to undertake the requisite controlled studies to determine the physiological limitations and trade-offs that marine mammals face while diving in the wild under varying environmental and nutritional conditions. For the past decade, Steller sea lions (Eumetopias jubatus) trained to swim and dive in the open ocean away from the physical confines of pools participated in studies that investigated the interactions between diving behaviour, energetic costs, physiological constraints, and prey availability. Many of these studies measured the cost of diving to understand how it varies with behaviour and environmental and physiological conditions. Collectively, these studies show that the type of diving (dive bouts or single dives), the level of underwater activity, the depth and duration of dives, and the nutritional status and physical condition of the animal affect the cost of diving and foraging. They show that dive depth, dive and surface duration, and the type of dive result in physiological adjustments (heart rate, gas exchange) that may be independent of energy expenditure. They also demonstrate that changes in prey abundance and nutritional status cause sea lions to alter the balance between time spent at the surface acquiring oxygen (and offloading CO2 and other metabolic by-products) and time spent at depth acquiring prey. These new insights into the physiological basis of diving behaviour further our understanding of the potential scope for behavioural responses of marine mammals to environmental changes, the energetic significance of these adjustments, and the consequences of approaching physiological limits.PostprintPeer reviewe

    Ca2+/calmodulin-dependent protein kinase kinase-β acts upstream of AMP-activated protein kinase in mammalian cells

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    SummaryAMP-activated protein kinase (AMPK) is the downstream component of a kinase cascade that plays a pivotal role in energy homeostasis. Activation of AMPK requires phosphorylation of threonine 172 (T172) within the T loop region of the catalytic α subunit. Recently, LKB1 was shown to activate AMPK. Here we show that AMPK is also activated by Ca2+/calmodulin-dependent protein kinase kinase (CaMKK). Overexpression of CaMKKβ in mammalian cells increases AMPK activity, whereas pharmacological inhibition of CaMKK, or downregulation of CaMKKβ using RNA interference, almost completely abolishes AMPK activation. CaMKKβ isolated from rat brain or expressed in E. coli phosphorylates and activates AMPK in vitro. In yeast, CaMKKβ expression rescues a mutant strain lacking the three kinases upstream of Snf1, the yeast homolog of AMPK. These results demonstrate that AMPK is regulated by at least two upstream kinases and suggest that AMPK may play a role in Ca2+-mediated signal transduction pathways

    Match performance in a reference futsal team during an international tournament – implications for talent development in soccer

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    Anecdotal evidence suggests that futsal can aid talent development for 11 a-side soccer through the potential for transfer of the game’s skills and constraints. However, additional scientific research is necessary to enhance understanding of the technical and physical demands of futsal and the potential returns for soccer player development. Accordingly, this study examined selected characteristics of physical (internal and external loads) and technical performance in international futsal match-play in order to study the potential of these for skill transfer and aiding soccer player development. Performance was investigated in futsal players (n = 16, 25.74±4.71 years) belonging to a national team during an international tournament. Pre-tournament fitness testing determined maximum heart rate (MHR) via the Yo-Yo IR1 test (194.6±11.1 beats min-1) to aid interpretation of internal load via heart rate measures during match-play. External load (accelerations and deceleration events) was measured using an inertial movement unit. Finally, post-tournament analysis of selected technical events was performed. Results reported a mean heart rate value during ‘court time’ of 164.7±22.3 beats min-1, which as a percentage of participants’ MHR was 87.7%±4.4%, and a mean peak MHR of 98.3±2.5%. Results showed 2.16±0.25 accelerating (>1.5 m·s-2) and 2.78±0.13 decelerating (>1.5 m·s-2) events per player per minute. Team statistics included 647 passing, ~51 dribbling and 78 set play events per team per game. Match analyses showed that 77.3% of ball receptions were completed with the sole of the foot. Assessment of two-footedness showed 80.1±16.7% of individual possessions used the dominant foot to receive and 84.1±10.7% to pass the ball thereby displaying strong foot dominance. These results have quantified characteristics of elite futsal match-play that are no doubt intrinsically related to the environmental and task constraints of the sport. In addition to enhancing understanding of futsal, there are potential learning returns and implications for skills transfer and the development of soccer players

    Regulation of ploidy and senescence by the AMPK-related kinase NUAK1.

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    Senescence is an irreversible cell-cycle arrest that is elicited by a wide range of factors, including replicative exhaustion. Emerging evidences suggest that cellular senescence contributes to ageing and acts as a tumour suppressor mechanism. To identify novel genes regulating senescence, we performed a loss-of-function screen on normal human diploid fibroblasts. We show that downregulation of the AMPK-related protein kinase 5 (ARK5 or NUAK1) results in extension of the cellular replicative lifespan. Interestingly, the levels of NUAK1 are upregulated during senescence whereas its ectopic expression triggers a premature senescence. Cells that constitutively express NUAK1 suffer gross aneuploidies and show diminished expression of the genomic stability regulator LATS1, whereas depletion of NUAK1 with shRNA exerts opposite effects. Interestingly, a dominant-negative form of LATS1 phenocopies NUAK1 effects. Moreover, we show that NUAK1 phosphorylates LATS1 at S464 and this has a role in controlling its stability. In summary, our work highlights a novel role for NUAK1 in the control of cellular senescence and cellular ploidy.We thank the members of the Laboratory for helpful discussions. We also thank Virginie Glippa and Julie Bertout for technical assistance. We thank H Esumi for the NUAK1 cDNA, E Hara and H Saya for the LATS1‐encoding vector. This work was carried out with the support of the ‘Association pour la Recherche sur le Cancer’, the ‘Fondation pour la Recherche Médicale Nord Pas de Calais’, the ‘Comité du Pas de Calais de la Ligue Nationale contre le Cancer’, the RTRS Fondation Synergie Lyon Cancer, and the Medical Research Council, UK.S

    Drop jump neuromuscular performance qualities associated with maximal horizontal deceleration ability in team sport athletes

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    The purpose of this study was to investigate associations between, and within, drop jump (DJ) neuromuscular performance (NMP) qualities and maximal horizontal deceleration ability. We also compared DJ NMP qualities in “high” versus “low” horizontal deceleration ability athletes. Twenty-nine university athletes performed: (1) DJs on force plates from 20 (DJ20) and 40 cm (DJ40) heights and (2) maximal horizontal deceleration, measured using radar, following a 20 m acceleration. Maximal horizontal deceleration was evaluated using deceleration (HDEC; m.s-2), across the entire deceleration phase and during early and late deceleration sub-phases. Of the DJ variables assessed, DJ20 and DJ40 reactive strength index (RSI) and concentric mean force had the largest correlations with HDEC (r = -0.54 to -0.61) and the largest differences between high and low HDEC groups (d = 1.20 to 1.40). These correlations were stronger with the early than late HDEC sub-phase (r = -0.54 to -0.66 vs. r = -0.24 to -0.40). Notably, eccentric mean force in DJ40 had large correlations with both DJ20 and DJ40 concentric mean force (r = 0.67 to 0.77), whereas at DJ20 these correlations were small (r = 0.22 to 0.40). Similarly, DJ40 eccentric mean force had a much larger difference between the high and low HDEC groups than DJ20 (d = 1.11 vs. 0.51). These findings suggest DJ RSI from either height may be used as a proxy for HDEC ability, while DJ kinetic analyses should use a higher height to distinguish those with a better capacity to generate eccentric braking forces under increased eccentric loading demands

    Cardiac Mesenchymal Stem Cell-Like Cells Derived from a Young Patient with Bicuspid Aortic Valve Disease Have a Prematurely Aged Phenotype.

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    There is significant interest in the role of stem cells in cardiac regeneration, and yet little is known about how cardiac disease progression affects native cardiac stem cells in the human heart. In this brief report, cardiac mesenchymal stem cell-like cells (CMSCLC) from the right atria of a 21-year-old female patient with a bicuspid aortic valve and aortic stenosis (referred to as biscuspid aortic valve disease BAVD-CMSCLC), were compared with those of a 78-year-old female patient undergoing coronary artery bypass surgery (referred to as coronary artery disease CAD-CMSCLC). Cells were analyzed for expression of MSC markers, ability to form CFU-Fs, metabolic activity, cell cycle kinetics, expression of NANOG and p16, and telomere length. The cardiac-derived cells expressed MSC markers and were able to form CFU-Fs, with higher rate of formation in CAD-CMSCLCs. BAVD-CMSCLCs did not display normal MSC morphology, had a much lower cell doubling rate, and were less metabolically active than CAD-CMSCLCs. Cell cycle analysis revealed a population of BAVD-CMSCLC in G2/M phase, whereas the bulk of CAD-CMSCLC were in the G0/G1 phase. BAVD-CMSCLC had lower expression of NANOG and shorter telomere lengths, but higher expression of p16 compared with the CAD-CMSCLC. In conclusion, BAVD-CMSCLC have a prematurely aged phenotype compared with CAD-CMSCLC, despite originating from a younger patient
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