182 research outputs found
Neuromuscular, physiological and perceptual responses to an elite netball tournament
To examine responses to an International netball tournament, female athletes (n= 11) played three matches over consecutive days. External (accelerometry) and internal (heart rate; HR, session; sRPE, and differential; dRPE, rating of perceived exertion) load measures quantified match intensity. On match-day mornings, and three days after match 3, well-being (brief assessment of mood; BAM+), biochemical (creatine kinase concentration; CK), neuromuscular (jump height; JH, peak power output; PPO) and endocrine function (salivary cortisol; C, testosterone; T, concentrations) were assessed. External load was similar between matches whereas dRPE and sRPE were greatest for match 3. Following match 1, CK increased, whereas BAM+, JH, C and T decreased. Following two matches, BAM+, PPO, and T decreased with CK increasing versus baseline. Following consecutive matches, CK (likely moderate; 27.9% ± 19.5%) and C (possibly moderate; 43.3% ± 46.8%) increased, whilst BAM+ (possibly moderate; −20.6% ± 24.4%) decreased. Three days post-tournament BAM+, T, PPO, and JH decreased. Mid-court elicited higher mean HR (possibly moderate; 3.7% ± 3.8%), internal and external intensities (possibly very large; 85.7% ± 49.6%) compared with goal-based positions. Consecutive matches revealed a dose–response relationship for well-being and physiological function; a response evident three days post-tournament
The neuromuscular, physiological, endocrine and perceptual responses to different training session orders in international female netball players
The 20 h responses of International female netball players to training days requiring two sessions (netball and strength, separated by two hours) ordered alternatively were examined. Eleven players completed strength followed by netball training two hours later (STR-NET), with the order reversed (NET-STR) on a separate day. Well-being, neuromuscular performance (jump height [JH], peak power output [PPO], peak velocity [PV]) and endocrine function (testosterone, cortisol concentrations) were measured before sessions one (PreS1) and two (PreS2), immediately after sessions one (IPS1) and two (IPS2), and 20 h post session one (20P). Session and differential ratings of perceived exertion (upper-body, cognitive/technical [RPE-T], lower-body, breathlessness) were collected, and accelerometry and heart rate measured netball load. Identification of clear between-order differences was based on the nonoverlap of the 95% confidence interval (95%CI) for mean differences relative to baseline. Compared to PreS1, greater increases in JH (percentage difference between trials; 95%CI: 9%; 4–14%), PPO (5%; 2–8%), PV (3%; 1–5%) and cortisol concentration (45%; 1–88%), and a greater decrease for testosterone/cortisol ratio (−35%; −72 to −2%) occurred at PreS2 in NET-STR. At 20P, greater decreases in JH (10%; 5–15%), PPO (4%; 1–8%) and PV (4%; 2–6%) were observed following STR-NET. No differences existed for well-being, whilst RPE-T was greater (15 AU; 3–26 AU) for strength training during NET-STR. Session order influenced neuromuscular and endocrine responses in International female netball players, highlighting session ordering as a key consideration when planning training
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Trends in North American net primary productivity derived from satellite observations, 1982-1998
Net primary productivity (NPP) in North America was computed for the years 1982–1998 using the Carnegie‐Ames‐Stanford approach (CASA) carbon cycle model. CASA was driven by a new, corrected satellite record of the normalized difference vegetation index at 8‐km spatial resolution. Regional trends in the 17‐year NPP record varied substantially across the continent. Croplands and grasslands of the Central Plains and eastern Canadian forests experienced summer increases in NPP. Peak NPP trends in Alaska and western Canada occurred in late spring or early summer, suggesting an earlier onset of the growing season in these regions. Forests and woodlands of the southeastern United States showed NPP increases in spring and fall, also suggesting an increase in the length of the growing season. An analysis of climate variables showed that summer precipitation increased in the Central Plains, indicating that climate changes probably play some role in increasing NPP in this region, though intensive management of agricultural ecosystems has also increased productivity. Similarly, increased summer precipitation possibly increased NPP in eastern Canada, but another possible explanation is forest recovery after insect damage. NPP in the southeastern United States increased in the absence of climate variation. Much of this region consists of aggressively managed forests, with young stand ages and intensive silviculture resulting in increased NPP. The high latitudes of western Canada and Alaska experienced spring warming that could have increased NPP in late spring or early summer
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Satellite-derived increases in net primary productivity across North America, 1982-1998
We used a new 17‐year, high spatial resolution satellite record and a carbon cycle model to explore how changing net primary productivity (NPP) contributed to a proposed carbon (C) sink in North America. We found a small but significant increase in NPP, 0.03 Pg C yr^(−2) or 8% over 17 years, that could explain a substantial fraction of the C sink. The largest increases occurred in the central and southeastern United States, eastern Canada, and northwestern North America, and were consistent with NPP trends derived from forest inventories and crop yields. Interannual NPP variability was small, implying that the large interannual variability in the C sink found in previous studies were driven by changes in heterotrophic respiration
Author Correction: Dynamic regulation of canonical TGFβ signalling by endothelial transcription factor ERG protects from liver fibrogenesis.
An amendment to this paper has been published and can be accessed via a link at the top of the paper
Tropical nighttime warming as a dominant driver of variability in the terrestrial carbon sink
The terrestrial biosphere is currently a strong carbon (C) sink but may switch to a source in the 21st century as climate-driven losses exceed CO2-driven C gains, thereby accelerating global warming. Although it has long been recognized that tropical climate plays a critical role in regulating interannual climate variability, the causal link between changes in temperature and precipitation and terrestrial processes remains uncertain. Here, we combine atmospheric mass balance, remote sensing-modeled datasets of vegetation C uptake, and climate datasets to characterize the temporal variability of the terrestrial C sink and determine the dominant climate drivers of this variability. We show that the interannual variability of global land C sink has grown by 50–100% over the past 50 y. We further find that interannual land C sink variability is most strongly linked to tropical nighttime warming, likely through respiration. This apparent sensitivity of respiration to nighttime temperatures, which are projected to increase faster than global average temperatures, suggests that C stored in tropical forests may be vulnerable to future warming
Trends in North American net primary productivity derived from satellite observations, 1982-1998
Net primary productivity (NPP) in North America was computed for the years 1982–1998 using the Carnegie‐Ames‐Stanford approach (CASA) carbon cycle model. CASA was driven by a new, corrected satellite record of the normalized difference vegetation index at 8‐km spatial resolution. Regional trends in the 17‐year NPP record varied substantially across the continent. Croplands and grasslands of the Central Plains and eastern Canadian forests experienced summer increases in NPP. Peak NPP trends in Alaska and western Canada occurred in late spring or early summer, suggesting an earlier onset of the growing season in these regions. Forests and woodlands of the southeastern United States showed NPP increases in spring and fall, also suggesting an increase in the length of the growing season. An analysis of climate variables showed that summer precipitation increased in the Central Plains, indicating that climate changes probably play some role in increasing NPP in this region, though intensive management of agricultural ecosystems has also increased productivity. Similarly, increased summer precipitation possibly increased NPP in eastern Canada, but another possible explanation is forest recovery after insect damage. NPP in the southeastern United States increased in the absence of climate variation. Much of this region consists of aggressively managed forests, with young stand ages and intensive silviculture resulting in increased NPP. The high latitudes of western Canada and Alaska experienced spring warming that could have increased NPP in late spring or early summer
Satellite-derived increases in net primary productivity across North America, 1982-1998
We used a new 17‐year, high spatial resolution satellite record and a carbon cycle model to explore how changing net primary productivity (NPP) contributed to a proposed carbon (C) sink in North America. We found a small but significant increase in NPP, 0.03 Pg C yr^(−2) or 8% over 17 years, that could explain a substantial fraction of the C sink. The largest increases occurred in the central and southeastern United States, eastern Canada, and northwestern North America, and were consistent with NPP trends derived from forest inventories and crop yields. Interannual NPP variability was small, implying that the large interannual variability in the C sink found in previous studies were driven by changes in heterotrophic respiration
Dynamic regulation of canonical TGF beta signalling by endothelial transcription factor ERG protects from liver fibrogenesis
The role of the endothelium in protecting from chronic liver disease and TGFβ-mediated
fibrosis remains unclear. Here we describe how the endothelial transcription factor
ETS-related gene (ERG) promotes liver homoeostasis by controlling canonical TGFβ-SMAD
signalling, driving the SMAD1 pathway while repressing SMAD3 activity. Molecular analysis
shows that ERG binds to SMAD3, restricting its access to DNA. Ablation of ERG expression
results in endothelial-to-mesenchymal transition (EndMT) and spontaneous liver
fibrogenesis in EC-specific constitutive hemi-deficient (ErgcEC-Het) and inducible homozygous
deficient mice (ErgiEC-KO), in a SMAD3-dependent manner. Acute administration of the
TNF-α inhibitor etanercept inhibits carbon tetrachloride (CCL4)-induced fibrogenesis in an
ERG-dependent manner in mice. Decreased ERG expression also correlates with EndMT in
tissues from patients with end-stage liver fibrosis. These studies identify a pathogenic
mechanism where loss of ERG causes endothelial-dependent liver fibrogenesis via regulation
of SMAD2/3. Moreover, ERG represents a promising candidate biomarker for assessing
EndMT in liver disease
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