1,572 research outputs found
Macrophage migratory inhibitory factor (MIF) profiles are associated with indicators of physical and psychosocial stress in professional rugby league players
Introduction: MIF is an inflammatory cytokine which has a remarkable array of functions, including immune, metabolic and angiogenic effects. There is substantial evidence linking MIF to hypothalamic-pituitary-adrenal (HPA) axis functions, with MIF hypothesised to counter-regulate the anti-inflammatory actions of glucocorticoids (GC) at least partially by reducing the GC-sensitivity of immune cells. There is also evidence that changes in MIF are part of the well-established bi-directional links between psychological stress factors and dysregulation of inflammatory systems and HPA function. In professional athletes there is a unique combination of both physical and psychosocial stress which has been hypothesised to include immune dysfunction. The current study examined the association between indicators of physical and psychosocial stress on changes in MIF across a competitive season in professional rugby league players.
Methods: Players (n=29) from a Sydney National Rugby League club participated in the study from February – August 2012. MIF was analysed in resting blood samples taken at least 24 hrs after the most recent exercise bout on six occasions approximately 1 month apart, with the first (baseline) sample taken prior to season start. From the same time points, data from standardised wellness questions was extracted from player diaries.
Results: A significant effect of Time was observed in MIF levels (p\u3c.001), with a nadir at time 4 (May), and no difference between baseline and final samples (Feb-Aug). To determine salient associations, change in MIF from baseline to time 4 was calculated, and found to be negatively associated with the change over the same time period in stress/mood, sleep and muscle soreness, such that better mood, sleep quality and less muscle soreness were associated with lower levels of MIF.
Conclusion: The current findings provide evidence that in a highly physically fit cohort, inflammatory markers are associated with indicators of both physical and psychosocial stress. MIF appears to be a reactive marker associated with stress and deserves further attention. Further, it may be important for athlete preparation to determine sleep and psychosocial stress influences on the homeostasis of inflammatory stress through GC function
Short- and long-term temperature responses of soil denitrifier net N2O efflux rates, inter-profile N2O dynamics, and microbial genetic potentials
Production and reduction of nitrous oxide (N2O) by soil denitrifiers influence atmospheric concentrations of this potent greenhouse gas. Accurate projections of the net N2O flux have three key uncertainties: (1) short- vs. long-term responses to warming, (2) interactions among soil horizons, and (3) temperature responses of different steps in the denitrification pathway. We addressed these uncertainties by sampling soil from a boreal forest climate transect encompassing a 5.2 ∘C difference in the mean annual temperature and incubating the soil horizons in isolation and together at three ecologically relevant temperatures in conditions that promote denitrification. Both short-term exposure to warmer temperatures and long-term exposure to a warmer climate increased N2O emissions from organic and mineral soils; an isotopic tracer suggested that an increase in N2O production was more important than a decline in N2O reduction. Short-term warming promoted the reduction of organic horizon-derived N2O by mineral soil when these horizons were incubated together. The abundance of nirS (a precursor gene for N2O production) was not sensitive to temperature, whereas that of nosZ clade I (a gene for N2O reduction) decreased with short-term warming in both horizons and was higher from a warmer climate. These results suggest a decoupling of gene abundance and process rates in these soils that differs across horizons and timescales. In spite of these variations, our results suggest a consistent, positive response of denitrifier-mediated net N2O efflux rates to temperature across timescales in these boreal forests. Our work also highlights the importance of understanding cross-horizon N2O fluxes for developing a predictive understanding of net N2O efflux from soils
Short- and long-term temperature responses of soil denitrifier net N2O efflux rates, inter2 profile N2O dynamics, and microbial genetic potentials
Production and reduction of nitrous oxide (N2O) by soil denitrifiers influence atmospheric concentrations of this potent greenhouse gas. Accurate projections of the net N2O flux have three key uncertainties: (1) short- vs. long-term responses to warming, (2) interactions among soil horizons, and (3) temperature responses of different steps in the denitrification pathway. We addressed these uncertainties by sampling soil from a boreal forest climate transect encompassing a 5.2 ∘C difference in the mean annual temperature and incubating the soil horizons in isolation and together at three ecologically relevant temperatures in conditions that promote denitrification. Both short-term exposure to warmer temperatures and long-term exposure to a warmer climate increased N2O emissions from organic and mineral soils; an isotopic tracer suggested that an increase in N2O production was more important than a decline in N2O reduction. Short-term warming promoted the reduction of organic horizon-derived N2O by mineral soil when these horizons were incubated together. The abundance of nirS (a precursor gene for N2O production) was not sensitive to temperature, whereas that of nosZ clade I (a gene for N2O reduction) decreased with short-term warming in both horizons and was higher from a warmer climate. These results suggest a decoupling of gene abundance and process rates in these soils that differs across horizons and timescales. In spite of these variations, our results suggest a consistent, positive response of denitrifier-mediated net N2O efflux rates to temperature across timescales in these boreal forests. Our work also highlights the importance of understanding cross-horizon N2O fluxes for developing a predictive understanding of net N2O efflux from soils
Habitat use of a coastal delphinid population investigated using passive acoustic monitoring
Funding: Marine Scotland Science and the Marine Alliance for Science and Technology for Scotland (MASTS) pooling initiative, and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.1. The population of bottlenose dolphins in eastern Scotland has undergone significant range expansion since the 1990s, when a Special Area of Conservation was established for the population. 2. Distribution of this population is well described within areas of its range where intensive work has been carried out, such as the inner Moray Firth, St Andrews Bay and the Tay estuary area. However, elsewhere in their range, habitat use is less well understood. 3. In this study, a large‐scale and long‐term passive acoustic array was used to gain a better understanding of bottlenose dolphin habitat use in eastern Scottish waters, complementing and augmenting existing visual surveys. 4. Data from the array were analysed using a three‐stage approach. First, acoustic occupancy results were reported; second, temporal trends were modelled; and third, a spatial–temporal‐habitat model of acoustic occupancy was created. 5. Results from the acoustic occupancy are in agreement with visual studies that found that areas near known foraging locations were consistently occupied. Results from the temporal trend analysis were inconclusive. Habitat modelling showed that, throughout their range, bottlenose dolphins are most likely to be detected closer to shore, and at a constant distance from shore, in deeper water.PostprintPeer reviewe
Whole body cryotherapy and recovery from exercise induced muscle damage: A systematic review
Introduction
Cold therapies are used regularly in medicine for their analgesic and anti-inflammatory effects. Whole-body cryotherapy (WBC) involves exposure to air maintained between -110 and -160oC, and is hypothesised to reduce pain, local and systemic inflammation. WBC has recently become popular in an exercise and sporting context as a recovery method after skeletal muscle damage, however, research examining the efficacy of WBC in an athletic context is minimal. This review seeks to summarise the evidence for the effects of WBC on exercise recovery measures.
Methods
Electronic database searches were conducted from March to April 2013. Six large online databases were used; MEDLINE, SPORTDiscus, Scopus, Web of Science, PubMed and AMED. The search targeted human studies with an exercise task, and WBC intervention. Results included randomised controlled trials (RCT’s), uncontrolled trials and crossover designs.
Results
A total of 8 studies were included in the review. Two RCT’s, four crossover trials and two uncontrolled trials were identified. Five studies showed WBC had no effect on markers of muscle damage or inflammation post exercise, while 3 studies show a positive effect. Three out of the eight studies measured maximal muscle force production and subjective pain levels following exercise and WBC, with two showing WBC had a positive effect on muscle force recovery and pain. A meta-analysis was not conducted due to the heterogeneity of the studies.
Conclusion
The current evidence for the efficacy of WBC on exercise recovery is unclear. Published studies report mixed findings, and the study designs make these results difficult to interpret. As WBC is proposed as an aid to recovery in an athletic population, repeated measures of performance, muscle force production and pain are of importance to the athlete, however, are minimally reported in the literature. Cold water immersion (CWI) is widely used in an athletic setting for recovery, and has much literature supporting its use for the reduction of pain post-exercise. Well-designed RCT’s with controlled exercise interventions targeting performance measures are needed, in particular comparison of WBC with CWI data is needed for evaluation
Effects of whole body cryotherapy and cold water immersion on immune and inflammatory markers following exercise induced muscle damage
Introduction: Cold therapies are used regularly in medicine for their analgesic and anti-inflammatory effects. Whole-body cryotherapy (WBC) involves exposure to air maintained between -110 and -160oC, and is hypothesised to reduce pain, local and systemic inflammation. WBC has recently become popular in an exercise and sporting context as a recovery method after skeletal muscle damage. However, research examining the efficacy of WBC in an athletic context is minimal, in particular, studies comparing WBC to currently accepted recovery methods are lacking. Cold water immersion (CWI) is a widely researched and applied method of skeletal muscle recovery in sport science. As yet, no study has compared the proposed new method of WBC and the currently practiced method of CWI. We have designed a randomised control trial to examine the efficacy of WBC, as compared with CWI on recovery from a bout of eccentric muscle damage.
Methods: Sixty healthy male subjects will perform skeletal muscle function tests and an eccentric muscle damage protocol of their left quadriceps femoris, using an isokinetic dynamometer. They will then be randomly assigned to one of 3 groups, WBC, CWI or a passive recovery control (PAS). The WBC will expose subjects to -160°C for 3min, using cold air. The CWI condition involves whole body exposure for 3min, in water maintained at 12°C. The PAS will have subjects seated comfortably at room temperature following the exercise protocol. Blood samples, muscle functional measurements and pain reports will be taken before muscle damage, immediately following damage, prior to therapy administration and post therapy. Further follow up measures to be taken 6 h post, 24 h and 7 days post. Blood samples will be analysed for changes in interleukins 6, 8 and 10, creatine kinase and leukocyte population kinetics.
Results: Testing is being conducted. Results to be presented at the international society of exercise immunology (ISEI) symposium in September 2013
Relationships between bone geometry, volumetric bone mineral density and bone microarchitecture of the distal radius and tibia with alcohol consumption
PurposeChronic heavy alcohol consumption is associated with bone density loss and increased fracture risk, while low levels of alcohol consumption have been reported as beneficial in some studies. However, studies relating alcohol consumption to bone geometry, volumetric bone mineral density (vBMD) and bone microarchitecture, as assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT), are lacking.MethodsHere we report an analysis from the Hertfordshire Cohort Study, in which we studied associations between HR-pQCT measures at the distal radius and tibia and alcohol consumption in 376 participants (198 men and 178 women) aged 72.1–81.4 years.ResultsA total of 30 (15.2%), 90 (45.5%) and 78 (39.4%) men drank minimal/none (< 1 unit/week), low (? 1 unit/week and < 11 units/week) and moderate/high (? 11 units/week) amounts of alcohol respectively. These figures were 74 (41.8%), 80 (45.2%) and 23 (13.0%) respectively in women for minimal/none (< 1 unit/week), low (? 1 unit/week and < 8 units/week) and moderate/high (? 8 units/week). At the distal radius, after adjustment for confounding factors (age, BMI, smoking status, dietary calcium intake, physical activity and socioeconomic status and years since menopause and HRT use for women), men that drank low alcohol had lower cortical thickness (p = 0.038), cortical vBMD (p = 0.033), and trabecular vBMD (p = 0.028) and higher trabecular separation (p = 0.043) than those that drank none/minimal alcohol. Similar differences were shown between minimal/none and moderate/high alcohol although these only reached statistical significance for the cortical parameters. Interestingly, after similar adjustment, women showed similar differences in the trabecular compartment between none/minimal alcohol and low alcohol at the distal tibia. However, women that drank moderate/high alcohol had significantly higher trabecular vBMD (p = 0.007), trabecular thickness (p = 0.026), and trabecular number (p = 0.042) and higher trabecular separation (p = 0.026) at the distal radius than those that drank low alcohol.ConclusionsOur results suggest that alcohol consumption (low and moderate/high) may have a detrimental impact on bone health in men in both the cortical and trabecular compartments at the distal radius with similar results in women in the trabecular compartment between none/minimal alcohol and low alcohol at the distal tibia suggesting that avoidance of alcohol may be beneficial for bone health.AbbreviationsaBMD, areal bone mineral density; BMI, body mass index; Ct. area, cortical area; Ct.vBMD, cortical density; Ct.Po, cortical porosity; Ct.Th, cortical thickness; DXA, dual energy X-ray absorptiometry; HCS, Hertfordshire Cohort Study; HRpQCT, high-resolution peripheral quantitative computed tomography; pQCT, peripheral quantitative computed tomography; Tt.area, total cross-sectional area; Tb.vBMD, trabecular BMD; Tb.N, trabecular number; Tb.Th, trabecular thickness; Tb.Sp, trabecular separation; vBMD, volumetric bone mineral density
Companion dog acquisition and mental well-being: a community-based three-arm controlled study
Background Dog ownership is suggested to improve mental well-being, although empirical evidence among community dog owners is limited. This study examined changes in human mental well-being following dog acquisition, including four measures: loneliness, positive and negative affect, and psychological distress. Methods We conducted an eight-month controlled study involving three groups (n = 71): 17 acquired a dog within 1 month of baseline (dog acquisition); 29 delayed dog acquisition until study completion (lagged control); and 25 had no intentions of acquiring a dog (community control). All participants completed the UCLA Loneliness Scale (possible scores 0–60), Positive and Negative Affect Schedule and Kessler10 at baseline, three-months and eight-months. We used repeated measures ANCOVAs to analyse data with owner age and sex included as covariates. Post-hoc tests were performed for significant effects (p \u3c 0.05). Results There was a statistically significant group by time interaction for loneliness (p = 0.03), with an estimated reduction of 8.41 units (95% CI -16.57, − 0.26) from baseline to three-months and 7.12 (95% CI -12.55, − 1.69) from baseline to eight-months in the dog acquisition group. The group by time interaction for positive affect was also significant (p = 0.03), although there was no change in the dog acquisition group. Conclusions Companion dog acquisition may reduce loneliness among community dog owners. Our study provides useful direction for future larger trials on the effects of dog ownership on human mental well-being
The literacy practices for assessment in the vocational curriculum - the case of Hospitality
This article explores two case studies of the literacy practices of assessment in the vocational curriculum. Previous studies have identified learning in the vocational curriculum as being assessment-driven and that subjects often associated with limited levels of literacy actually require multiple literacy practices from students. Drawing upon studies of the literacy practices of assessment in the teaching of Hospitality, the study explores the academic and occupational forms of reading and writing required of students. These literacy practices are often invisible to both students and staff and yet are central to the success of students in relation to attainment. The article suggests that vocational subjects may actually be more demanding in the range of literacies required for assessment than is often considered to be the case
Bovine tuberculosis in working foxhounds: lessons learned from a complex public health investigation
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