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Leisure‐time physical activity (LTPA) decreases the risk of dementia, whereas occupational physical activity (OPA) possibly increases the risk. Yet, previous findings are mixed. We therefore aimed to investigate the effect of LTPA and OPA, respectively, on dementia among men and women. In this observational, longitudinal study, we used data from the second wave of a population‐based cohort from the municipality of Copenhagen as baseline. Data were collected in 1981–1983, and 10 343 participants were followed until the end of 2016. LTPA and OPA were self‐reported, and information on dementia diagnoses and redemption of dementia medication was obtained at an individual level from national health registers. We used Poisson regression to analyze the association between LTPA/OPA and dementia and adjusted for self‐reported age, socioeconomic factors, stress, and cardiovascular risk factors (smoking, alcohol, body mass index, and blood pressure). A higher level of LTPA was associated with a lower dementia risk among men, but we found no clear association among women. OPA and dementia were not associated among men, but occupationally active women who reported OPA in terms of walking, lifting, and heavy work had a higher risk of dementia than women with sedentary jobs. This study supported earlier findings of a protective effect of LTPA on dementia among men. Women in physically demanding jobs possibly have a higher risk of dementia, yet this finding warrants further investigation in future studies. [ABSTRACT FROM AUTHOR]

The phase transition between galaxies and quasars is often identified with the rare population of hyper-luminous, hot dust-obscured galaxies. Galaxy formation models predict these systems to grow via mergers, that can deliver large amounts of gas toward their centers, induce intense bursts of star formation and feed their supermassive black holes. Here we report the detection of 24 galaxies emitting Lyman-α emission on projected physical scales of about 400 kpc around the hyper-luminous hot dust-obscured galaxy W0410-0913, at redshift z = 3.631, using Very Large Telescope observations. While this indicates that W0410-0913 evolves in a very dense environment, we do not find clear signs of mergers that could sustain its growth. Data suggest that if mergers occurred, as models expect, these would involve less massive satellites, with only a moderate impact on the internal interstellar medium of W0410-0913, which is sustained by a rotationally-supported fast-rotating molecular disk, as Atacama Large Millimeter Array observations suggest. Lyman-alpha emission is one of the observational probes for the high-redshift universe. Here, the authors show several Lyman-alpha emitting companion galaxies around the hot dust-obscured galaxy W0410-091 suggesting that the galaxy evolves in a very dense environment. [ABSTRACT FROM AUTHOR]

Stabilized compressed earth block (CEB) structures are popular in developing countries because of their low cost, sustainable use of indigenous materials, and inherent simplicity. Interlocking CEB blocks are dry stacked (no mortar in the joints), reinforced through flues and grouted. CEBs are typically used for single story homes and school houses. The current design practice for CEB structures in regions with severe natural hazards (typhoons and earthquakes) is questionable in terms of structural integrity. This is accentuated by the complete lack of experimental out-of-plane load testing of CEB walls. Scientific evidence reported in this paper has the potential to improve the current design practice to make this a safer construction form. Five CEB walls were built according to current design practice in Indonesia and Thailand, and subjected to out-of-plane loading. Two walls were full-scale panels and the remaining three walls were 1.1 m tall. All tests showed flexure dominated behavior, except for one full scale wall in which shear dominated failure was observed in the stiffening element. Results from the experimentation showed that the CEB walls were relatively flexible, mainly due to slack in the dry-stack joints, and that the current US masonry design code procedures (MSJC-11, Building code requirements for masonry structures (TMS 402-11/ACI 530-11/ASCE 5-11) (2011)) adequately predict the wall flexural strength. A moment-curvature based model was proposed for prediction of the out-of-plane force-displacement response and validated by the experimental results. [ABSTRACT FROM AUTHOR]

We present a photometric and spectroscopic study of a reddened type Ic supernova (SN) 2005at. We report our results based on the available data of SN 2005at, including late-time observations from the Spitzer Space Telescope and the Hubble Space Telescope. In particular, late-time mid-infrared observations are something rare for type Ib/c SNe. In our study we find SN 2005at to be very similar photometrically and spectroscopically to another nearby type Ic SN 2007gr, underlining the prototypical nature of this well-followed type Ic event. The spectroscopy of both events shows similar narrow spectral line features. The radio observations of SN 2005at are consistent with fast evolution and low luminosity at radio wavelengths. The late-time Spitzer data suggest the presence of an unresolved light echo from interstellar dust and dust formation in the ejecta, both of which are unique observations for a type Ic SN. The late-time Hubble observations reveal a faint point source coincident with SN 2005at, which is very likely either a declining light echo of the SN or a compact cluster. For completeness we study ground-based pre-explosion archival images of the explosion site of SN 2005at, however this only yielded very shallow upper limits for the SN progenitor star. We derive a host galaxy extinction of AV ≈ 1.9 mag for SN 2005at, which is relatively high for a SN in a normal spiral galaxy not viewed edge-on. [ABSTRACT FROM AUTHOR]

We study the prospects for constraining the ionized fraction of the intergalactic medium (IGM) at z > 6 with the next generation of large Lyα emitter surveys. We make predictions for the upcoming Subaru Hyper Suprime-Cam (HSC) Lyα survey and a hypothetical spectroscopic survey performed with the James Webb Space Telescope (JWST). Considering various scenarios where the observed evolution of the Lyα luminosity function of Lyα emitters at z > 6 is explained partly by an increasingly neutral IGM and partly by intrinsic galaxy evolution, we show how clustering measurements will be able to distinguish between these scenarios. We find that the HSC survey should be able to detect the additional clustering induced by a neutral IGM if the global IGM neutral fraction is greater than ∼20 per cent at z = 6.5. If measurements of the Lyα equivalent widths (EWs) are also available, neutral fractions as small as 10 per cent may be detectable by looking for correlation between the EW and the local number density of objects. In this case, if it should turn out that the IGM is significantly neutral at z = 6.5 and the intrinsic EW distribution is relatively narrow, the observed EWs can also be used to construct a map of the locations and approximate sizes of the largest ionized regions. For the JWST survey, the results appear a bit less optimistic. Since such surveys probe a large range of redshifts, the effects of the IGM will be mixed up with any intrinsic galaxy evolution that is present, making it difficult to disentangle the effects. However, we show that a survey with the JWST will have a possibility of observing a large group of galaxies at z ∼ 7, which would be a strong indication of a partially neutral IGM. [ABSTRACT FROM AUTHOR]

Aims. We study the effects of an inhomogeneous interstellar medium (ISM) on the strength and the shape of the Lyman alpha (Lyα) line in starburst galaxies. Methods. Using our 3D Monte Carlo Lyα radiation transfer code, we have studied the radiative transfer of Lyα, UV, and optical continuum photons in homogeneous and clumpy shells of neutral hydrogen and dust surrounding a central source. Our simulations predict the Lyα and continuum escape fraction, the Lyα equivalent width EW(Lyα), the Lyα line profile, and their dependence on the geometry of the gas distribution and the main input physical parameters. Results. The ISM clumpiness is found to have a strong impact on the Lyα line radiative transfer, leading to a strong dependence of the emergent features of the Lyα line (escape fraction, EW(Lyα)) on the ISM morphology. Although a clumpy and dusty ISM appears more transparent to radiation (both line and continuum) compared to an equivalent homogeneous ISM of equal dust optical depth, we find that the Lyα photons are, in general, still more attenuated than UV continuum radiation. As a consequence, the observed equivalent width of the Lyα line (EWobs(Lyα)) is lower than the intrinsic one (EWint(Lyα)) for nearly all clumpy ISM configurations being considered. There are, however, special conditions under which Lyα photons escape more easily than the continuum, resulting in an enhanced EWobs(Lyα). The requirement for this to happen is that the ISM is almost static (galactic outflows ⩽200 km s-1), extremely clumpy (with density contrasts >107 in HI between clumps and the interclump medium), and very dusty (E(B-V) > 0:30). When these conditions are fulfilled, the emergent Lyα line profile generally shows no velocity shift and little asymmetry. Otherwise, the Lyα line profile is very similar to the one expected for homogeneous media. Conclusions. Given the asymmetry and velocity shifts generally observed in star-forming galaxies with Lyα emission, we therefore conclude that clumping is unlikely to significantly enhance their relative Lyα/UV transmission. [ABSTRACT FROM AUTHOR]

Aims To investigate the effects of short-term, reduced-volume sprint interval training ( SIT) compared to traditional exercise recommendations ( TER) in sedentary obese men. Methods Sixteen subjects [37.8 ± 5.8 years; body mass index ( BMI) 32.8 ± 4.7 kg/m2] were randomly allocated to 2 weeks of either SIT (6 sessions of 8-12 × 10 s sprints) or TER [10 sessions of 30 min at 65% peak oxygen consumption ( VO2peak)] cycle exercise. Fasting plasma glucose, insulin, non-esterified fatty acids ( NEFA), homeostasis model assessment of insulin sensitivity ( HOMA-IR), body composition and VO2peak were assessed at baseline and approximately 72 h after the final training bout. Skeletal muscle biopsy samples were also obtained before and 72 h after training and analysed for AS160 phosphorylation and COX II, COX IV, GLUT-4, Nur77 and SIRT1 protein expression. Results No changes in BMI, body composition, VO2peak, glucose, insulin, NEFA and HOMA-IR were observed after training, either within or between groups. Skeletal muscle markers of glucose metabolism and mitochondrial function also remained unaltered after 2 weeks of exercise training. Conclusions Our findings show that 2 weeks of reduced-volume SIT or TER did not elicit any measurable metabolic adaptations in sedentary obese men. Further work is needed to determine the minimal amount of exercise required for short-term adaptations in this population. [ABSTRACT FROM AUTHOR]

In this study, we compared the reliability of short-term resting heart rate (HR) variability (HRV) and postexercise parasympathetic reactivation (i.e., HR recovery (HRR) and HRV) indices following either submaximal or supramaximal exercise. On 4 different occasions, beat-to-beat HR was recorded in 15 healthy males (21.5 ± 1.4 yr) during 5 min of seated rest, followed by submaximal (Sub) and supramaximal (Supra) exercise bouts; both exercise bouts were followed by 5 min of seated recovery. Reliability of all HR-derived indices was assessed by the typical error of measurement expressed as a coefficient of variation (CV, % ). CV for HRV indices ranged from 4 to 17 %, 7 to 27 % and 41 to 82 % for time domain, spectral and ratio indices, respectively. The CV for HRR ranged from 15 to 32 %. Spectral CVs for HRV were lower at rest compared with Supra (e. g., natural logarithm of the high frequency range (LnHF); 12.6 vs. 26.2 %; p = 0.02). HRR reliability was not different between Sub and Supra (25 vs. 14 %; p = 0.10). The present study found discrepancy in the CVs of vagal-related heart rate indices; a finding that should be appreciated when assessing changes in these variables. Further, Supra exercise was shown to worsen the reliability of HRV-spectral indices. [ABSTRACT FROM AUTHOR]

This is the second paper of a series reporting on the results from a survey conducted with the ESO VLT/X-shooter spectrograph. We target high-metallicity damped Lyman α absorbers (DLAs) with the aim of investigating the relation between galaxies detected in emission and those detected in absorption. Here, we report on the discovery of the galaxy counterpart of the DLA on the line-of-sight to the quasar SDSS J 163609.0 (hereafter Q 1636). The galaxy counterpart of the DLA is detected in the [O ]λ5007 and [O ] emission lines redshifted into the NIR at an impact parameter of 2.0 arcsec (16 kpc at ). Lyα emission is not detected down to a 3σ detection limit of cm, which, compared to the strength of the oxygen lines, implies that Lyα emission from this galaxy is suppressed by more than an order of magnitude. The DLA has one of the highest metallicities measured so far at comparable redshifts. We find evidence for substantial depletion of refractory elements on to dust grains. Fitting the main metal line component of the DLA, which is located at , we measure the metal abundances from Zn , S , Si , Cr , Mn , Fe and Ni to be and , respectively. In addition, we detect absorption in the Lyman and Werner bands of molecular hydrogen (H), which represents the first detection of H molecules with X-shooter. The background quasar Q 1636 is amongst the reddest QSOs at redshifts from the SDSS catalogue. Its UV to NIR spectrum is well fitted by a composite QSO spectrum reddened by SMC-/LMC-like extinction curves at with a significant amount of extinction given by mag. This supports previous claims that there may be more metal-rich DLAs missing from current samples due to dust reddening of the background QSOs. The fact that there is evidence for dust both in the central emitting regions of the galaxy (as evidenced by the lack of Lyα emission) and at an impact parameter of 16 kpc (as probed by the DLA) suggests that dust is widespread in this system. [ABSTRACT FROM AUTHOR]

Out-of-plane fl exural testing of three full-scale unreinforced masonry (URM) walls seismically retrofi tted using post-tensioning is reported. The selected wall confi gurations were representative of common URM walls that were vulnerable to out-of-plane failure, and imitated heritage URM construction by using salvaged clay brick masonry and ASTM type O mortar. Varying levels of pre-compression were applied to the test walls using a single mechanically restrained tendon inserted into a cavity at the centre of each test wall. Three different types of tendons were used for post-tensioning of the test walls, being threaded mild steel bar and sheathed greased seven wire strands (with tensile yield strengths of 1300 and 1675 MPa). Behaviour of the post-tensioned URM walls was compared to the response of a non retrofi tted URM wall, with the out-of-plane fl exural strength of the post-tensioned masonry walls observed to range from 2.9 to 10.3 times the strength of the non retrofi tted URM wall. Several aspects pertaining to the seismic behaviour of post-tensioned masonry walls were investigated, including tendon stress variation, damage patterns, force displacement behaviour, initial stiffness and displacement capacity. Test results were compared with equations developed in previous studies, and it was established that the walls that were post-tensioned using seven-wire strands had measured strengths that compared favourably with predicted values, whereas the wall that was post-tensioned using mild steel bar had failed at a lower measured strength than the predicted value. [ABSTRACT FROM AUTHOR]

We have initiated a survey using the newly commissioned X-shooter spectrograph to target candidate relatively metal-rich damped Lyα absorbers (DLAs). Our rationale is that high-metallicity DLAs due to the luminosity-metallicity relation likely will have the most luminous galaxy counterparts. In addition, the spectral coverage of X-shooter allows us to search for not only Lyα emission, but also rest-frame optical emission lines. We have chosen DLAs where the strongest rest-frame optical lines ([O ], [O ], Hβ and Hα) fall in the near-infrared atmospheric transmission bands. In this first paper resulting from the survey, we report on the discovery of the galaxy counterpart of the DLA towards the quasar Q 0946. This DLA is amongst the most metal-rich DLAs studied so far at comparable redshifts and there is evidence for substantial depletion of refractory elements on to dust grains. We measure metallicities from Zn , Si , Ni , Mn and Fe of and , respectively. The galaxy is detected in the Lyα, [O ]λλ4959, 5007 and Hα emission lines at an impact parameter of about 0.8 arcsec (6 kpc at ). Based on the Hα line, we infer a star formation rate of 10 M yr, which is a lower limit due to the possibility of slit loss. Compared to the recently determined Hα luminosity function for galaxies, the DLA-galaxy counterpart has a luminosity of . The emission-line ratios are 4.0 (Lyα/Hα) and 1.2 ([O ]/Hα). In particular, the Lyα line shows clear evidence for resonant scattering effects, namely an asymmetric, redshifted (relative to the systemic redshift) component and a much weaker blueshifted component. The fact that the blueshifted component is relatively weak indicates the presence of a galactic wind. The properties of the galaxy counterpart of this DLA are consistent with the prediction that metal-rich DLAs are associated with the most luminous of the DLA-galaxy counterparts. [ABSTRACT FROM AUTHOR]

Performance in intense exercise events, such as Olympic rowing, swimming, kayak, track running and track cycling events, involves energy contribution from aerobic and anaerobic sources. As aerobic energy supply dominates the total energy requirements after ∼75 s of near maximal effort, and has the greatest potential for improvement with training, the majority of training for these events is generally aimed at increasing aerobic metabolic capacity. A short-term period (six to eight sessions over 2–4 weeks) of high-intensity interval training (consisting of repeated exercise bouts performed close to or well above the maximal oxygen uptake intensity, interspersed with low-intensity exercise or complete rest) can elicit increases in intense exercise performance of 2–4% in well-trained athletes. The influence of high-volume training is less discussed, but its importance should not be downplayed, as high-volume training also induces important metabolic adaptations. While the metabolic adaptations that occur with high-volume training and high-intensity training show considerable overlap, the molecular events that signal for these adaptations may be different. A polarized approach to training, whereby ∼75% of total training volume is performed at low intensities, and 10–15% is performed at very high intensities, has been suggested as an optimal training intensity distribution for elite athletes who perform intense exercise events. [ABSTRACT FROM AUTHOR]

Laboratory tests of fitness variables have previously been shown to be valid predictors of cycling time-trial performance. However, due to the influence of drafting, tactics and the variability of power output in mass-start road races, comparisons between laboratory tests and competition performance are limited. The purpose of this study was to compare the power produced in the laboratory Power Profile (PP) test and Maximum Mean Power (MMP) analysis of competition data. Ten male cyclists (mean±SD: 20.8 ±1.5 y, 67.3 ± 5.5 kg, VO2max 72.7 ± 5.1 mL· k g-1·min-1) completed a PP test within 14 days of competing in a series of road races. No differences were found between PP results and MMP analysis of competition data for durations of 60-600s, total work or estimates of critical power and the fixed amount of work that can be completed above critical power (W'). Self-selected cadence was 15±7rpm higher in the lab. These results indicate that the PP test is an ecologically valid assessment of power producing capacity over cycling specific durations. In combination with MMP analysis, this may be a useful tool for quantifying elements of cycling specific performance in competitive cyclists. [ABSTRACT FROM AUTHOR]

The aims of the present study were to (1) assess relationships between running performance and parasympathetic function both at rest and following exercise, and (2) examine changes in heart rate (HR)-derived indices throughout an 8-week period training program in runners. In 14 moderately trained runners (36 +/- 7 years), resting vagal-related HR variability (HRV) indices were measured daily, while exercise HR and post-exercise HR recovery (HRR) and HRV indices were measured fortnightly. Maximal aerobic speed (MAS) and 10 km running performance were assessed before and after the training intervention. Correlations (r > 0.60, P < 0.01) were observed between changes in vagal-related indices and changes in MAS and 10 km running time. Exercise HR decreased progressively during the training period (P < 0.01). In the 11 subjects who lowered their 10 km running time >0.5% (responders), resting vagal-related indices showed a progressively increasing trend (time effect P = 0.03) and qualitative indications of possibly and likely higher values during week 7 [+7% (90% CI -3.7;17.0)] and week 9 [+10% (90% CI -1.5;23)] compared with pre-training values, respectively. Post-exercise HRV showed similar changes, despite less pronounced between-group differences. HRR showed a relatively early possible decrease at week 3 [-20% (90% CI -42;10)], with only slight reductions near the end of the program. The results illustrate the potential of resting, exercise and post-exercise HR measurements for both assessing and predicting the impact of aerobic training on endurance running performance. [ABSTRACT FROM AUTHOR]

Team sport match play requires athletes to perform a number of repeated shuttle sprints. However, the acute effects of these repeated sprint sequences on lactic acidosis and resulting autonomic state perturbation are not known. The aim of this study was to observe and compare the blood lactate and post-exercise cardiac autonomic responses of a repeated shuttle-sprint ability test with the 30-15 Intermittent Fitness Test (30-15IFT); the latter test representing a standard for exhaustive supramaximal effort. Thirteen adult team sport players performed the repeated shuttle-sprint ability test and the 30-15IFT on separate days in a counter-balanced order. The repeated shuttle-sprint ability test consisted of six repetitions of maximal 2 x 15 m shuttle sprints (-5s) departing every 20s, while the 30-15IFT involved progressive 30s shuttle runs interspersed with 15s of passive recovery until exhaustion. Blood lactate was measured before and after the tests, while autonomic responses were assessed using immediate heart rate recovery and heart rate variability indices. Peak blood lactate (10.6±2.1 vs. 10.2±2.8mM) and heart beats recovered in one minute after exercise cessation (36.4±7.8 vs. 39.3 ±7.9bpm) were similar after both the repeated shuttle-sprint ability test and the 30-15IFT. With the exception of the vagal-related time-varying root mean square of successive R-R interval differences at each 30s, which recovered earlier after the repeated shuttle-sprint ability test compared with 30-15IFT, all heart rate variability indices decreased similarly after both tests in comparison to baseline values. In conclusion, the repeated shuttle-sprint ability test was shown to induce comparable levels of lactic acidosis and post-exercise autonomic state as the 30-15IFT. These levels of metabolic and autonomic states are likely to occur during team sport match play. [ABSTRACT FROM AUTHOR]

The aim of the present study was to assess the influence of body posture on post-submaximal exercise parasympathetic reactivation and to examine whether this influence was preserved under a heightened sympathetic background. On four occasions, eleven moderately trained subjects (22.1 ± 3.0 years old) performed, in random order, two consecutive submaximal running bouts (CTs), each followed by 5 min passive recovery in an upright (Up), sitting (Sit), supine (Sup) or supine with legs up position (SupLu). Between both CTs, participants performed 150 s of supramaximal intermittent running (SI). Parasympathetic reactivation was assessed from heart rate recovery (HRR) and variability (HRV; e.g. rMSSD30 s) indices calculated during the 5 min recovery periods [i.e. before (N) and after SI (post-SI)]. In the N condition, Sup position was associated with a faster and greater increase in rMSSD30 s than Sit and SupLu (both P < 0.01), which were all higher compared with Up ( P < 0.001). A ‘time’ effect was shown in Sit, Sup and SupLu (all P < 0.05), but not in Up ( P= 0.99). All N values were higher than post-SI values ( P < 0.001), except for Up, where a trend was apparent ( P= 0.06). In the post-SI condition, a position effect was preserved for HRR ( P < 0.001), but not for HRV indices ( P= 0.99 for rMSSD30 s). In conclusion, the supine position accelerated and increased parasympathetic reactivation more than the other three positions, but the posture effect was less evident following supramaximal exercise. In the context of an accentuated sympathetic background (i.e. post-SI), postexercise HRV indices are less gravity dependent than HRR, reflecting more the exercise-related changes in parasympathetic activity. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the effect of active (AR) versus passive recovery (PR) on muscle deoxygenation during short repeated maximal running. Ten male team sport athletes (26.9±3.7y) performed 6 repeated maximal 4-s sprints interspersed with 21 s of either AR (2 m.s 1) or PR (standing) on a non-motorized treadmill. Mean running speed (AVSPmean), percentage speed decrement (Sp%Dec), oxygen uptake (VO2), deoxyhemoglobin (HHb) and blood lactate ([La]b) were computed for each recovery condition. Compared to PR, AVSPmean was lower (3.79±0.28 vs. 4.09±0.32m.s-1; P<0.001) and Sp%Dec higher(7.2±3.7 vs. 3.2±0.1.3%; P< 0.001) for AR. Mean VO2 (3.64± 0.44 vs. 2.91 ±0.47L. min-1, P<0.001), HHb (94.4± 16.8 vs. 83.4±4.8% of HHb during the first sprint, P=0.02) and [La]b (13.5±2.5 vs. 12.7±2.2mmol.l-1, P=0.03) were significantly higher during AR compared to PR. In conclusion, during run-based repeated sprinting, AR was associated with reduced repeated sprint ability and higher muscle deoxygenation. [ABSTRACT FROM AUTHOR]

This study compared the effect of high-intensity interval training (HIT) versus specific game-based handball training (HBT) on handball performance parameters. Thirty-two highly- trained adolescents (15.5±0.9 y) were assigned to either HIT (n= 17) or HBT (n= 15) groups, that performed either HIT or HBT twice per week for 10 weeks. The HIT consisted of 12-24 x 15s runs at 95% of the speed reached at the end of the 30- 15 Intermittent Fitness Test (VIFT) interspersed with 15s passive recovery, while the HBT consisted of small-sided handball games performed over a similar time period. Before and after training, performance was assessed with a counter movement jump (CMJ), 10 m sprint time (10 m), best (RSAbest) and mean (RSAmean) times on a repeated sprint ability (RSA) test, the VIFT and the intermittent endurance index (IEI). After training, RSAbest (3.5 ± 2.7%), RSAmean (3.9 ± 2.2%) and VIFT (+6.3±5.2%) were improved (P<0.05), but there was no difference between groups. In conclusion, both HIT and HBT were found to be effective training modes for adolescent handball players. However, HBT should be considered as the preferred training method due to its higher game-based specificity. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the influence of starting strategy on time trial performance in the heat. Eleven endurance trained male cyclists (30�5 years, 79.5�4.6 kg, V˙O2max 58.5�5.0 ml.kg.−1 min−1) performed four 20-km time trials in the heat (32.7�0.7�C and 55% relative humidity). The first time trial was completed at a self-selected pace (SPTT). During the following time trials, subjects performed the initial 2.5-km at power outputs 10% above (10% ATT), 10% below (10% BTT) or equal (ETT) to that of the average power during the initial 2.5-km of the self-selected trial; the remaining 17.5-km was self-paced. Throughout each time trial, power output, rectal temperature, skin temperature, heat storage, pain intensity and thermal sensation were taken. Despite significantly (P<0.05) greater power outputs for 10% BTT (273�45W) compared with the ETT (267�48W) and 10% ATT (265�41W) during the final 17.5-km, overall 20-km performance time was not significantly different amongst trials. There were no differences in any of the other measured variables between trials. These data show that varying starting power by �10% did not affect 20 km time trial performance in the heat. [ABSTRACT FROM AUTHOR]

The aim of the present study was to assess the effect of cold water immersion (CWI) on postexercise parasympathetic reactivation. Ten male cyclists (age, 29 ± 6 yr) performed two repeated supramaximal cycling exercises (SE1 and SE2) interspersed with a 20-mm passive recovery period, during which they were randomly assigned to either 5 mm of CWI in 14°C or a control (N) condition where they sat in an environmental chamber (35.0 ± 0.3°C and 40.0 ± 3.0% relative humidity). Rectal temperature (Tre) and beat-to-beat heart rate (HR) were recorded continuously. The time constant of HR recovery (HRRτ) and a time (30-s) varying vagal-related HR variability (HRV) index (rMSSD30s) were assessed during the 6-min period immediately following exercise. Resting vagal-related HRV indexes were calculated during 3-min periods 2 min before and 3 min after SE1 and SE2. Results showed no effect of CWI on Tre (P = 0.29), SE performance (P = 0.76), and HRRT (P = 0.61). In contrast, all vagal-related HRV indexes were decreased after SE1 (P < 0.001) and tended to decrease even further after SE2 under N condition but not with CWI. When compared with the N condition, CWI increased HRV indexes before (P < 0.05) and rMSSD30s after (P < 0.05) SE2. Our study shows that CWI can significantly restore the impaired vagal-related HRV indexes observed after supramaximal exercise. CWI may serve as a simple and effective means to accelerate parasympathetic reactivation during the immediate period following supramaximal exercise. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the accuracy of the Velotron cycle ergometer and the SRM power meter using a dynamic calibration rig over a range of exercise protocols commonly applied in laboratory settings. These trials included two sustained constant power trials (250W and 414W), two incremental power trials and three high-intensity interval power trials. To further compare the two systems, 15 subjects performed three dynamic 30km performance time trials. The Velotron and SRM displayed accurate measurements of power during both constant power trials (<1 % error). However, during high-intensity interval trials the Velotron and SRM were found to be less accurate (3.0%, Cl=1.6-4.5% and -2.6%, CI=-3.2--2.0% error, respectively). During the dynamic 30km time trials, power measured by the Velotron was 3.7±1.9% (Cl=2.9-4.8%) greater than that measured by the SRM. In conclusion, the accuracy of the Velotron cycle ergometer and the SRM power meter appears to be dependent on the type of test being performed. Furthermore, as each power monitoring system measures power at various positions (i.e. bottom bracket vs. rear wheel), caution should be taken when comparing power across the two systems, particularly when power is variable. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effect of exercise-induced plasma volume expansion on post-exercise parasympathetic reactivation. Before (D(0)) and 2 days after (D(+2)) a supramaximal exercise session, 11 men (21.4 +/- 2.6 years and BMI = 23.0 +/- 1.4) performed 6-min of submaximal running where heart rate (HR) recovery (HRR) and HR variability (HRV) indices were calculated during the first 10 min of recovery. Relative plasma volume changes (PV) were calculated using changes in hematocrit and hemoglobin measured over consecutive mornings from D(0) to D(+2). Parasympathetic reactivation was evaluated through HRR and vagal-related indexes calculated during a stationary period of recovery. Compared with D(0), PV (+4.8%, P < 0.01) and all vagal-related HRV indices were significantly higher at D(+2) (all P < 0.05). HRR was not different between trials. Changes in HRV indices, but not HRR, were related to PV (all P < 0.01). HRR and HRV indices characterize distinct independent aspects of cardiac parasympathetic function, with HRV indices being more sensitive to changes in plasma volume than HRR. [ABSTRACT FROM AUTHOR]

The aims of the present study were to determine the influence of familiarization on the reliability of power output during a dynamic 30-km cycling trial and to determine the test-retest reliability following a 6-week period. Nine trained male cyclists performed five self-paced 30-km cycling trials, which contained three 250-m sprints and three 1-km sprints. The first three of these trials were performed in consecutive weeks (Week 1, Week 2 and Week 3), while the latter two trials were consecutively conducted 6 wk following (Week 9 and Week 10). Subjects were instructed to complete each sprint, as well as the entire trial in the least time possible. Reproducibility in average power output over the entire 30-km trial for Week 2 and 3 alone (coefficient of variation, CV = 2.4%, intra-class correlation coefficient, ICC=0.93) was better than for Week I and 2 (CV=5.5%, ICC=0.77) and Week 9 and 10 alone (CV = 5.3%, ICC = 0.57). These results indicate that high reliability during a dynamic 30-km cycling trial may be obtained after a single familiarization trial when subsequent trials are performed within 7 days. However, if cyclists do not perform trials for six weeks, the same level of reliability is not maintained. [ABSTRACT FROM AUTHOR]

The aim of the present study was to examine the ability of the critical velocity (CV) and the endurance index (El) to assess endurance performance during intermittent exercise. Thirteen subjects performed two intermittent runs: 15-s runs intersected with 15s of passive recovery (15/15) and 30-s runs with 30-s rest (30/30). Runs were performed until exhaustion at three intensities (100,95 and 90% of the speed reached at the end of the 30-15 intermittent fitness test, VIFT) to calculate i) CV from the slope of the linear relationship between the total covered distance and exhaustion time (ET) (iCV): ii) anaerobic distance capacity from the y-intercept of the distance/duration relationship (iADC); and iii) El from the relationship between the fraction of VIFT at which the runs were performed and the log-transformed ET (iEI). Anaerobic capacity was indirectly assessed by the final velocity achieved during the Maximal Anaerobic Running Test (VMART). ET was longer for 15/15 than for 30/30 runs at similar intensities. iCV15/15 and iCV30/30 were not influenced by changes in ET and were highly dependent on VIFT. Neither iADC15/15 nor iADC30/30 were related to VMART. In contrast, iEI15/15 was higher than iEI30/30, and corresponded with the higher ET. In conclusion, only iEI estimated endurance capacity during repeated intermittent running. [ABSTRACT FROM AUTHOR]

This study investigated the hypothesis that muscle damage would be attenuated in muscles subjected to passive hyperthermia 1 day prior to exercise. Fifteen male students performed 24 maximal eccentric actions of the elbow flexors with one arm; the opposite arm performed the same exercise 2–4 weeks later. The elbow flexors of one arm received a microwave diathermy treatment that increased muscle temperature to over 40°C, 16–20 h prior to the exercise. The contralateral arm acted as an untreated control. Maximal voluntary isometric contraction strength (MVC), range of motion (ROM), upper arm circumference, muscle soreness, plasma creatine kinase activity and myoglobin concentration were measured 1 day prior to exercise, immediately before and after exercise, and daily for 4 days following exercise. Changes in the criterion measures were compared between conditions (treatment vs. control) using a two-way repeated measures ANOVA with a significance level of P < 0.05. All measures changed significantly following exercise, but the treatment arm showed a significantly faster recovery of MVC, a smaller change in ROM, and less muscle soreness compared with the control arm. However, the protective effect conferred by the diathermy treatment was significantly less effective compared with that seen in the second bout performed 4–6 weeks after the initial bout by a subgroup of the subjects ( n = 11) using the control arm. These results suggest that passive hyperthermia treatment 1 day prior to eccentric exercise-induced muscle damage has a prophylactic effect, but the effect is not as strong as the repeated bout effect. [ABSTRACT FROM AUTHOR]

This study investigated the hypothesis that muscle damage would be attenuated in muscles subjected to passive hyperthermia 1 day prior to exercise. Fifteen male students performed 24 maximal eccentric actions of the elbow flexors with one arm; the opposite arm performed the same exercise 2-4 weeks later. The elbow flexors of one arm received a microwave diathermy treatment that increased muscle temperature to over 40 degrees C, 16-20 h prior to the exercise. The contralateral arm acted as an untreated control. Maximal voluntary isometric contraction strength (MVC), range of motion (ROM), upper arm circumference, muscle soreness, plasma creatine kinase activity and myoglobin concentration were measured 1 day prior to exercise, immediately before and after exercise, and daily for 4 days following exercise. Changes in the criterion measures were compared between conditions (treatment vs. control) using a two-way repeated measures ANOVA with a significance level of P < 0.05. All measures changed significantly following exercise, but the treatment arm showed a significantly faster recovery of MVC, a smaller change in ROM, and less muscle soreness compared with the control arm. However, the protective effect conferred by the diathermy treatment was significantly less effective compared with that seen in the second bout performed 4-6 weeks after the initial bout by a subgroup of the subjects (n = 11) using the control arm. These results suggest that passive hyperthermia treatment 1 day prior to eccentric exercise-induced muscle damage has a prophylactic effect, but the effect is not as strong as the repeated bout effect. [ABSTRACT FROM AUTHOR]

Background: Numerous laboratory based studies have documented that aggressive hydration strategies (∼1-2 litres/h) are required to minimise a rise in core temperature and minimise the deleterious effects of hyperthermia on performance. However, field data on the relations between hydration level, core body temperature, and performance are rare. Objective: To measure core temperature (Tcore) in triathletes during a 226 km Ironman triathlon, and to compare Tcore with markers of hydration status after the event. Method: Before and immediately after the 2004 Ironman Western Australia event (mean (SD) ambient temperature 23.3 (1.9) °C (range 19-26°C) and 60 (14)% relative humidity (44-87%)) body mass, plasma concentrations of sodium ([Na+]), potassium ([K+]), and chloride ([Cl-]), and urine specific gravity were measured in 10 well trained triathletes. Tcore was measured intermittently during the event using an ingestible pill telemetry system, and heart rate was measured throughout. Results: Mean (SD) performance time in the Ironman triathlon was 611 (49) minutes; heart rate was 143 (9) beats/mm (83 (6)% of maximum) and Tcore was 38.1(0.3) . Body mass significantly declined during the race by 2.3 (1.2) kg (-3.0 (1 .5)%; p<0.05), whereas urine specific gravity significantly increased (1.011(0.005) to 1.0170 (0.008) g/ml; p<0.05) and plasma [Na+], [K+], and [Cl-] did not change. Changes in body mass were not related to finishing Tcore (r = -0.16), plasma [Na+] (r = 0.31), or urine specific gravity (r = -0.37). Conclusion: In contrast with previous laboratory based studies examining the influence of hypohydration on performance, a body mass loss of up to 3% was found to be tolerated by well trained triathletes during an Ironman competition in warm conditions without any evidence of thermoregulatory failure. [ABSTRACT FROM AUTHOR]

This study evaluates the Chronic effects on the central nervous system of exposure to low concentrations of toluene (TWA < 20 ppm) on workers in a rotogravure plant. Ninety-eight male workers from a selection pool of 107 (92%) were examined neuropsychologically using a Cognitive Function Scanner, and neurologically by computerized methods measuring co-ordination ability, tremor and position stability. In addition measures of symptoms and former exposure were obtained by questionnaire. The workers were divided into three groups: Group 0 with no exposure to organic solvents (n = 19); Group 1 with exposure to TWA <20 ppm of toluene for less than 13 years (n = 30) and Group 2 with exposure for more than 12 years (n = 49). Within Group 2, 37 (75%) had been exposed at levels exceeding 100 ppm for 10+ years before 1983. No significant differences were found between Group 0 and Group 1 regarding symptoms and results of the applied tests. Group 2 differed significantly from the two other groups in scoring higher on a symptom index (p = 0.04), particularly regarding concentration ability, reduced memory and fatigue. Group 2 scored significantly poorer on tests for visuospatial function, number learning and word recognition, while no differences regarding neurological functions were observed. The study showed no differences regarding neuropsychological and neurological functions between a non-exposed group of male workers and workers exposed to toluene less than 13 years at TWA <20 ppm. However, long-term exposure to TWA (time weighted average) of toluene exceeding 100 ppm was associated with impaired neuropsychological function. [ABSTRACT FROM PUBLISHER]

The article discusses the effectiveness of several cooling techniques for the treatment of hyperthermia. It is noted that both experimental and empirical evidence would suggest that there is no perfect method, since most techniques are not likely to be well tolerated by the patient with discomfort, excessive shivering, as well as numbness and parasthesiae sometimes being reported. Future work is suggested to assess the impact of different treatment conditions, in various populations on postexercise autonomic control after exercise-induced hyperthermia.

Gamma-ray burst afterglow observations in the Swift era have a perceived lack of achromatic jet breaks compared with the BeppoSAX era. We present our multi-wavelength analysis of GRB 060206 as an illustrative example of how inferences of jet breaks from optical and X-ray data might differ. The results of temporal and spectral analyses are compared, and attempts are made to fit the data within the context of the standard blast wave model. We find that while the break appears more pronounced in the optical and evidence for it from the X-ray alone is weak, the data are actually consistent with an achromatic break at about 16 h. This break and the light curves fit standard blast wave models, either as a jet break or as an injection break. As the pre- Swift sample of afterglows are dominated by optical observations, and in the Swift era most well-sampled light curves are in the X-ray, caution is needed when making a direct comparison between the two samples, and when making definite statements on the absence of achromatic breaks. [ABSTRACT FROM AUTHOR]