Recovery Modes Research Articles

The Effect Of Three Different Modes Of Recovery On Lactate Removal Rate Following A Maximal Effort Swim In Masters Level Swimmers

During swim competition, active recovery swimming (ARS) following the competitive event is often encouraged to hasten recovery prior to subsequent events. Often a single main competition pool precludes the opportunity for ARS, so alternative activities of active recovery cycling (ARC) or passive recovery (PR) are used. PURPOSE: To compare the rate of change in blood lactate using ARS, ARC and PR, following a maximal effort swim. METHODS: 8 (3 male, 5 female) masters level swimmers (age range 26-61) volunteered for the study. Each subject completed a 500 meter swim warm-up at moderate pace. After completion of the warm-up each subject completed a 100 meter freestyle maximal effort swim, followed by one of three randomly assigned 15 min recovery trials with blood lactate obtained by finger puncture at 3, 5, 10 and 15 min post swim. The three trials consisted of: PR (subject sat on the pool deck), ARS (swim freestyle @ a pace 30 sec/100 meter slower than the max effort), and ARC (airdyne cycling @ 60% HRR). Statistical analysis by ANOVA (p<.05) were applied to these data. RESULTS: At 3, 5, 10, and 15 min post swim, lactate values (mmol) were 6.5, 6.5, 6.2, and 5.4 for PR, 7.2, 6.3, 5.4, and 4.8 for ARS, and 7.1, 5.6, 4.7 and 4.1 for ARC, respectively. There were no differences (p >.05) among the three recovery modes in terms of % lactic acid clearance at 5 and 10 min post swim, however at 15 min ARC clearance of 42% was greater (p<.05) than PR (18%), but similar to ARS (34%). CONCLUSION: Large individual variation in lactate efflux, as well as swim technique may, in part, be responsible for heterogeneous recovery responses. Improved lactate clearance appears allied with active recovery regardless of the mode of exercise.

Behavior of Deformed Droplets in an Immiscible Polymer Blend: A Comparative Study of Electron Microscopy and Small‐Angle X‐Ray Scattering

AbstractThe deformation of dispersed droplets in a PS/LLDPE 95:5 blend during uniaxial elongation and after cessation of the flow was studied. The behavior of the dispersed droplets during elongation is in a good agreement with a prediction of the modified capillary number model using transient elongational viscosities. The phase structure changes after the elongation was studied in relaxation and recovery modes. The morphology was investigated using scanning electron microscopy and small‐angle X‐ray scattering. Thus the dimensions of the dispersed particles and their degree of orientation were estimated. It was shown that the SAXS as an integral method gives new additional information which is hardly accessible by SEM as a method providing local information about discrete locations in the sample. The results of both methods proved that the stress in the sample is a decisive parameter determining the morphology development after cessation of the flow.magnified image

Effect of NO on extinction and re-ignition of vortex-perturbed hydrogen flames

The catalytic effect of nitric oxide (NO) on the dynamics of extinction and re-ignition of a vortex-perturbed non-premixed hydrogen–air flame is studied in a counterflow burner. A diffusion flame is established with counterflowing streams of nitrogen-diluted hydrogen at ambient temperature and air heated to a range of temperatures that brackets the auto-ignition temperature. Localized extinction is induced by impulsively driving a fuel-side toroidal vortex into the steady flame, and the recovery of the extinguished region is monitored by planar laser-induced fluorescence (PLIF) of the hydroxyl radical (OH). The dynamics of flame recovery depend on the air temperature and fuel concentration, and four different recovery modes are identified. These modes involve combinations of edge-flame propagation and the expansion of an auto-ignition kernel that forms within the extinguished region. The addition of a small amount of NO significantly alters the re-ignition process by shifting the balance between chain-termination and chain-propagation reactions to enhance auto-ignition. The ignition enhancement by this catalytic effect causes a shift in the conditions that govern the recovery modes. In addition, the effects of NO concentration and vortex strength on the flame recovery are examined. Direct numerical simulations of the flame–vortex interaction with and without NO doping show how the small amount of OH produced by NO-catalyzed reactions has a significant impact on the development of an auto-ignition kernel. This joint experimental and numerical study provides detailed insight into the interaction between transient flows and ignition processes.

GeoDTN+Nav: Geographic DTN Routing with Navigator Prediction for Urban Vehicular Environments

Position-based routing has proven to be well suited for highly dynamic environment such as Vehicular Ad Hoc Networks (VANET) due to its simplicity. Greedy Perimeter Stateless Routing (GPSR) and Greedy Perimeter Coordinator Routing (GPCR) both use greedy algorithms to forward packets by selecting relays with the best progress towards the destination or use a recovery mode in case such solutions fail. These protocols could forward packets efficiently given that the underlying network is fully connected. However, the dynamic nature of vehicular network, such as vehicle density, traffic pattern, and radio obstacles could create unconnected networks partitions. To this end, we propose GeoDTN+Nav, a hybrid geographic routing solution enhancing the standard greedy and recovery modes exploiting the vehicular mobility and on-board vehicular navigation systems to efficiently deliver packets even in partitioned networks. GeoDTN+Nav outperforms standard geographic routing protocols such as GPSR and GPCR because it is able to estimate network partitions and then improves partitions reachability by using a store-carry-forward procedure when necessary. We propose a virtual navigation interface (VNI) to provide generalized route information to optimize such forwarding procedure. We finally evaluate the benefit of our approach first analytically and then with simulations. By using delay tolerant forwarding in sparse networks, GeoDTN+Nav greatly increases the packet delivery ratio of geographic routing protocols and provides comparable routing delay to benchmark DTN algorithms.

Human heat balance during postexercise recovery: separating metabolic and nonthermal effects

Previous studies report greater postexercise heat loss responses during active recovery relative to inactive recovery despite similar core temperatures between conditions. Differences have been ascribed to nonthermal factors influencing heat loss response control since elevations in metabolism during active recovery are assumed to be insufficient to change core temperature and modify heat loss responses. However, from a heat balance perspective, different rates of total heat loss with corresponding rates of metabolism are possible at any core temperature. Seven male volunteers cycled at 75% of Vo(2peak) in the Snellen whole body air calorimeter regulated at 25.0 degrees C, 30% relative humidity (RH), for 15 min followed by 30 min of active (AR) or inactive (IR) recovery. Relative to IR, a greater rate of metabolic heat production (M - W) during AR was paralleled by a greater rate of total heat loss (H(L)) and a greater local sweat rate, despite similar esophageal temperatures between conditions. At end-recovery, rate of body heat storage, that is, [(M - W) - H(L)] approached zero similarly in both conditions, with M - W and H(L) elevated during AR by 91 +/- 26 W and 93 +/- 25 W, respectively. Despite a higher M - W during AR, change in body heat content from calorimetry was similar between conditions due to a slower relative decrease in H(L) during AR, suggesting an influence of nonthermal factors. In conclusion, different levels of heat loss are possible at similar core temperatures during recovery modes of different metabolic rates. Evidence for nonthermal influences upon heat loss responses must therefore be sought after accounting for differences in heat production.

Hyperthermia Modifies the Nonthermal Contribution to Postexercise Heat Loss Responses

This study investigated the nonthermoregulatory control of cutaneous vascular conductance (CVC) and sweating during recovery from exercise-induced hyperthermia as well as possible sex-related differences in these responses. Two hypotheses were tested in this study: 1) active and passive recovery would be more effective in attenuating the fall in mean arterial pressure (MAP) than inactive recovery, but CVC and sweat rate responses would be similar between all recovery modes; and 2) the magnitude of the change in postexercise heat loss and hemodynamic responses between recovery modes would be similar between sexes. Nine males and nine females were rendered hyperthermic (esophageal temperature = 39.5 degrees C) by exercise, followed by 60 min of 1) active, 2) inactive, and 3) passive recovery. CVC, sweat rate, and MAP were recorded at baseline, after 2, 5, 12, and 20 min, and at every 10 min until the end of recovery. MAP was elevated above inactive recovery by 6 +/- 2 and 4 +/- 1 mm Hg for active and passive recovery, respectively (P < 0.001). No differences were observed between modes during the initial 10 min of recovery for CVC and 50 min of recovery for sweat rate. However, relative to inactive recovery CVC and sweat rate were subsequently greater by 16.2 +/- 5.8% of CVCpeak and 0.28 +/- 0.04 mg.min.cm, respectively, during active recovery, and by 11.6 +/- 2.9% of CVCpeak and 0.23 +/- 0.03 mg.min.cm, respectively, during passive recovery. We conclude that in the presence of a greater thermal drive associated with hyperthermia, the influence of nonthermal input on postexercise heat loss responses is still observed. However, thermal control predominates over nonthermal factors in the first 10 min of recovery for CVC and for up to 50 min postexercise for sweating. Sex did not influence the effect of recovery mode on any variable.

Pre-Exercise Alkalosis and Acid-Base Recovery

The aim of this study was to observe the influence of pre-exercise sodium bicarbonate (NaHCO3) ingestion and varying recovery modes on acid-base recovery from a single bout of supramaximal exercise. Nine male subjects completed four separate, randomized cycle ergometer exercise trials to volitional fatigue at 120% maximum power output, under the following conditions: 0.3 g.kg(-1) BW NaHCO3 ingestion with passive recovery (BICARB P), 0.3 g.kg (-1) BW NaHCO3 ingestion with active recovery (BICARB A), placebo ingestion with passive recovery (PLAC P) and placebo ingestion with active recovery (PLAC A). Capillary blood samples were obtained every minute for 15 min during recovery. Significant main effects for pH were observed for time (F = 42.1, p < 0.001), intervention (BICARB and PLAC) (F = 1117.3, p < 0.001) and recovery condition (F = 150.0, p < 0.001), as the BICARB condition reduced acid-base perturbation. Significant interaction effects were observed between conditions (BICARB and PLAC) for active and passive recovery modes (F = 29.1, p < 0.001) as the active recovery facilitated H+ removal better than the passive condition. Pre-exercise alkalosis attenuates blood acid-base perturbations from supramaximal exercise to exhaustion, regardless of whether the recovery mode is active or passive. These findings suggest that individuals may benefit from introducing a pre-exercise alkalotic condition while including passive recovery during high-intensity training protocols.

Comparison of Recovery Strategies on Muscle Performance After Fatiguing Exercise

The objective of this study was to assess the influence of different relaxation modes: stretching (ST), active recovery (AR), and passive recovery (PR) on muscle relaxation after dynamic exercise of the quadriceps femoris. Ten healthy male volunteers between 24 and 38 yrs of age participated in this study. After the warm-up, subjects performed three sets of dynamic leg extension and flexion (at an angle of 20-110 degrees) at 50% of previously determined maximal voluntary contraction (MVC), with 30 secs. of rest between sets. Immediately after completing the leg exercise, one of the relaxation methods was applied, in a randomized order (AR, PR, ST). Then, subjects performed isometric knee extension at 50% of MVC to the point of fatigue, and surface electromyogram (EMG) of the vastus lateralis muscle was measured. After AR, the mean MVC was significantly (P < 0.05) higher than after PR and ST. Moreover, there was no difference in MVC between AR and baseline (P > 0.05). Total time of the effort during EMG measurement was significantly lower for all three recovery modes than at baseline. During the effort after both PR and ST, there was no significant increase in motor unit activation, but a significant increase was noted after AR (P < 0.05). There was no difference in frequency between any of the recovery modes and baseline (P > 0.05). The results of this study suggest that the most appropriate and effective recovery mode after dynamic muscle fatigue involves light, active exercises, such as cycling with minimal resistance.

Does neuromuscular electrical stimulation influence muscle recovery after maximal isokinetic exercise?

Neuromuscular electrical stimulation (ES) and passive recovery (PR) were compared in ten healthy men after a provocation exercise inducing delayed onset of muscle soreness (DOMS). The exercise consisted of 3 sets of 30 maximal eccentric contractions performed by the knee flexor muscles of the dominant leg on an isokinetic dynamometer at 60°/s angular velocity. There was an interval of 8 weeks between both bouts and the order of the recovery mode (ES or PR) was block-randomly assigned. ES recovery consisted of a 25-min continuous and non-tetanic (5 Hz) stimulation of the hamstring muscles. Concentric and eccentric hamstrings peak torques were evaluated before and immediately after the provocation exercise, after the recovery period, as well as 24 h (d1), 48 h (d2), 72 h (d3) and 168 h (d7) after the bout. Subjective perception of muscle soreness (VAS, 0-10 a.u.) was evaluated before exercise and at dl, d2, d3 and d7. To assess the CK activity, five blood samples were drawn before exercise and at dl, d2, d3 and d7. For both recovery modes, the greatest reductions in isokinetic muscle performances were measured on d2 (66.3 ± 24.1% of initial values (ES) vs. 57.4 ± 26.5% (PR) for the concentric mode and 55.6 ± 16% (ES) vs. 53.1 ± 19.3% (PR) for the eccentric mode). d2 also corresponded to the highest painful sensations (5.4 ± 2.14 a.u. (ES) vs. 6.15 ± 2.55 a.u. (PR)). Peak activities of CK were reached on d3 (47507 ± 19973 IU/1 (ES) vs. 75887 ± 41962 IU/1 (PR)). Serum CK was lower with ES than PR at d3 (p ≤ 0.05) but all other parameters changed in a manner that was not statistically different between the two recovery protocols (p > 0.05). This strong trend could be explained by an electro-induced hyperperfusion that may efficiently wash out the muscle from the cellular debris resulting from the initial injury, and hence diminish the inflammatory response and the delayed amplification of tissue damages.

The Effects of Electrical Stimulation and Submaximal Swimming on Blood Lactate Following a Maximal Effort 200 Yard Frontcrawl

PURPOSE: Researchers have demonstrated that submaximal swimming (SMS) can reduce peak blood lactate concentrations ([BLA-]) to near baseline levels. H-wave® is a trans cutaneous electrical stimulator used to reduce peripheral edema by inducing low intensity muscle contractions; this may be used as an alternative recovery mode. The purpose of this study was to evaluate the effect of recovery mode on lactate removal. METHODS: Thirty competitive swimmers (males, n=19; females, n=11) with a mean age of 17.7±2.9 y, height of 1.8±0.1 m, and weight of 67.4±10.7 kg volunteered for the study; mean sprint times were 109.95±4.02 s and 121.60±3.94 s for males and females, respectively. Participants swam a 1,200 – 1,500 yd warm-up, sprinted a 200 yd frontcrawl, and completed a 20 min randomized-counterbalanced recovery. Recovery modes were denned as follows: SMS (8x100 yd repeats at 65% of 200 yd maximum speed); H-wave® (30 mA, 2 Hz; latissimus dorsi and rectus femoris); and, rest (seated). Lactate samples were denned as follows: peak (3 min post-sprint), mid-recovery (10 min into recovery), and post-recovery (following the final 10 min). RESULTS: Resultant blood lactates (mmol/L) were as follows (peak, mid-recovery, and post-recovery, respectively): SMS, 5.96±2.35, 3.50±1.57, and 1.60±0.57;H-wave®, 6.25±1.99, 4.46±1.79, and 3.12±1.41; rest, 6.32±2.17, 5.19±1.93, and 4.11 ±1.35. A repeated measures 3x3 (recovery mode × time) ANOVA revealed a significant interaction which was followed up by a Scheffe post hoc test to identify the source of the interaction. Submaximal swim recovery resulted in [BLA-] significantly lower (p<0.05) than rest at mid-recovery, and [BLA-] significantly lower (p<0.05) than both H-wave® and rest at post-recovery. H-wave® lead to a significantly lower (p<0.05) [BLA-] than rest at post-recovery. CONCLUSION: It appears that both recovery treatments, SMS and H-wave®, remove BLA- faster than rest recovery, with SMS proving to be the most effective

Experimental and numerical investigation of solid particles thermal energy storage unit

A two-dimensional separate phases formulation is used to develop a numerical analysis of the transient response of a cylindrical packed bed thermal energy storage system, which is randomly packed with spheres having uniform sizes and encapsulated the paraffin wax as a phase change material (PCM), with air as a working fluid flowing through the bed. The fluid energy equation was transformed by finite difference approximation and solved by Alternating Direction Implicit scheme, while the PCM energy equation was solved using fully explicit scheme. This analysis is valid for fluids of various Prandtl numbers. It can be applied for both charging and recovery modes and for a broad range of Reynolds numbers. Measurements of both fluid and PCM temperature were conducted at different axial and radial positions and at different operating parameters. Experimental measurements of temperature distribution compare favorably with the numerical results over a broad range of Reynolds numbers.

Nonthermoregulatory control of cutaneous vascular conductance and sweating during recovery from dynamic exercise in women

The purpose of the study was to examine the effect of 1) active (loadless pedaling), 2) passive (assisted pedaling), and 3) inactive (motionless) recovery modes on mean arterial pressure (MAP), cutaneous vascular conductance (CVC), and sweat rate during recovery after 15 min of dynamic exercise in women. It was hypothesized that an active recovery mode would be most effective in attenuating the fall in MAP, CVC, and sweating during exercise recovery. Ten female subjects performed 15 min of cycle ergometer exercise at 70% of their predetermined peak oxygen consumption followed by 20 min of 1) active, 2) passive, or 3) inactive recovery. Mean skin temperature (Tsk), esophageal temperature (Tes), skin blood flow, sweating, cardiac output (CO), stroke volume (SV), heart rate (HR), total peripheral resistance (TPR), and MAP were recorded at baseline, end exercise, and 2, 5, 8, 12, 15, and 20 min postexercise. Cutaneous vascular conductance (CVC) was calculated as the ratio of laser-Doppler blood flow to MAP. In the active recovery mode, CVC, sweat rate, MAP, CO, and SV remained elevated over inactive values (P < 0.05). The passive mode was equally as effective as the active mode in maintaining MAP. Sweat rate was different among all modes after 12 min of recovery (P < 0.05). TPR during active recovery remained significantly lower than during recovery in the inactive mode (P < 0.05). No differences in either Tes or Tsk were observed among conditions. The results indicate that CVC can be modulated by central command and possibly cardiopulmonary baroreceptors in women. However, differences in sweat rate may be influenced by factors such as central command, mechanoreceptor stimulation, or cardiopulmonary baroreceptors.

Effects Of Different Recovery Methods Following Futsal Matches

There is a lack of information on the effect of recovery modes following team sport matches. PURPOSE This study aimed at investigating the most appropriate recovery mode following futsal matches. METHODS Ten futsal players (age: 23 ± 2 yrs; body mass 73 ± 7 kg; VO2max 52.2 ± 2.7 ml.kg-1·min-1; HRmax 196 ± 6 beat·min-1; Lamax 12.8 ± 2.6 mM) participated in this study. Data were collected twice a week for two weeks, when friendly matches were scheduled. Heart rates (HR), blood lactate (La), and rate of perceived exertion (RPE) were used to evaluate the intensity of the matches. At the end of the match, participants were randomly assigned one of the four 20-minute recovery protocols: 1) sitting rest (R); 2) low intensity dry-aerobic exercises (D); 3) low intensity shallow-water exercises (W); and 4) electrostimulation (E). Before, after the match, and after a 4-hour rest, photocells were used to measure athletes's counter movement jump (CMJ), bounce jumping (BJ), and 10m sprint performances. Salivary cortisol and athlete's leg muscle pain (MP) scales were collected before, at the end of the match, after a 4-hour rest, and the morning after the match. Urinary catecholamines were collected the morning of the match and the day after. The criteria for full recovery were afternoon test performances at least 97% of the morning pre-match ones. At the end of the experimental period, participants ranked the recovery modes by means of a 10-point likert scale. A Chi-square test was applied for heart rate counts and ANOVA was applied to test performances and hormonal values (p<0.05). RESULTS A preliminary analysis ascertained that morning pre-match test performances, cortisol, and MP values did not show any significant difference. Furthermore, no significant difference was shown between intensities (HR, La, and RPE) of the four matches. Cortisol values showed significant (F(3, 102) = 19.00 p <0.001) decreases during the day of the match and increases the morning after the match. Although catecholamine values were higher the morning after the match, no significant difference was found. After the game significant reductions for CMJ (F(2, 72) = 9.2 p <0.001) and 10m (F(2, 72) = 3.6 p <0.05) performances were found with no significant difference between recovery modes. However, D tended to show the best percentages of full recovery (range 60–100%). Recovery modes showed significant differences (F(3, 36) = 5.3 p <0.01) in the likert scale (E = 7.8 ± 1.4; W = 7.6 ± 2.1; D = 6.6 ± 1.8; and R = 5.2 ± 0.8). CONCLUSION Although recovery process seems not affected by active or passive modes, further studies are needed to fully elucidate the underlying mechanisms of recovery following training and match play.

Disconnected Processes, Mechanisms and Architecture for Mobile E-Business

With the tremendous advances in hand-held computing and communication capabilities, rapid proliferation of mobile devices, and decreasing device costs, we are seeing a growth in mobile e-business in various consumer and business markets. In this paper, we present a novel architecture and framework for end-to-end mobile e-business applications (e.g., point of sales). The architecture takes into consideration disconnection, application context, synchronization, transactions and failure recovery modes to provide mobile users with seamless and transparent access to business transactions and business-context specific data. In our architecture, we consider a novel business process design based on state-machines and event management to handle disconnection, resource limitations and failures. We designed, implemented and deployed a system for mobile e-business on clients (e.g., PDAs and PocketPCs) integrated with private exchanges and sell-side servers. The state-machine model with failure recovery mechanisms enables handling of one-to-many and many-to-one disconnections in large mobile e-business environments. The e-business framework on mobile clients is implemented based on J2ME, Webservices, and open XML standards. A detailed performance study of commerce transactions was done on different mobile client devices with diverse computing, memory and storage capabilities. We compare the performance of a purchasing application and the middleware on various devices such as PDAs and Laptops. We demonstrated that for small devices with limited capability the performance is reasonable. For devices with more computing capability, the response time is excellent.

Effects of Recovery Modes after Knee Extensor Muscles Eccentric Contractions

This study aimed to evaluate the benefit of using low-intensity running or electromyostimulation (EMS) to hasten the recovery process from eccentric-contraction-induced injury. Before and 30 min, 24 h, 48 h, and 96 h after a one-legged downhill run, electrical stimulations were applied to the femoral nerve of healthy volunteers. Superimposed twitches were delivered during isometric maximal voluntary contraction (MVC) to determine the voluntary activation level (%VA). For 4 d after the exercise, each subject performed either (i) 30 min of running at 50% VO2max, (ii) 30 min of low-frequency EMS on the lower limb extensor muscles, or (iii) passive recovery. Recovery time courses of the different variables did not differ significantly among the three experimental conditions. MVC decreased 30 min after the exercise and did not recover thereafter (P < 0.001). Percent VA was depressed after the exercise (P < 0.05) but did not contribute to MVC decrement thereafter. Mechanical responses to 80- and 20-Hz stimulation (P80 and P20, respectively) were significantly reduced over time (P < 0.01 and P < 0.001, respectively). Interestingly, MVC, P20, and P80 decrements were not statistically different (-9.6 +/- 14.5%, -13.2 +/- 14.2%, and -12.3 +/- 11.3%, respectively) at 48 h, and the P20.P80(-1) ratio showed complete recovery at this time. The different recovery modes had no significant effect on the recovery time course of contractile properties. The prolonged torque loss is mainly due to peripheral alterations. Our results suggest that an alteration of the excitation-contraction coupling might be involved during the first 2 d after the eccentric exercise. From 2 to 4 d, damage to force-generating structures could account for the remaining torque deficit.

Control of cutaneous vascular conductance and sweating during recovery from dynamic exercise in humans.

The purpose of the study was to examine the effect of 1) passive (assisted pedaling), 2) active (loadless pedaling), and 3) inactive (motionless) recovery modes on mean arterial pressure (MAP), skin blood flow (SkBF), and sweating during recovery after 15 min of dynamic exercise. It was hypothesized that an active recovery mode would be most effective in attenuating the fall in MAP, SkBF, and sweating during exercise recovery. Six male subjects performed 15 min of cycle ergometer exercise at 70% of their predetermined peak oxygen consumption followed by 15 min of 1) active, 2) passive, or 3) inactive recovery. Mean skin temperature (T(sk)), esophageal temperature (T(es)), SkBF, sweating, cardiac output (CO), stroke volume (SV), heart rate (HR), total peripheral resistance (TPR), and MAP were recorded at baseline, end exercise, and 2, 5, 8, 12, and 15 min postexercise. Cutaneous vascular conductance (CVC) was calculated as the ratio of laser-Doppler blood flow to MAP. In the active and passive recovery modes, CVC, sweat rate, MAP, CO, and SV remained elevated over inactive values (P < 0.05). The passive mode was equally as effective as the active mode in maintaining CO, SV, MAP, CVC, and sweat rate above inactive recovery. Sweat rate was different among all modes after 8 min of recovery (P < 0.05). TPR during active recovery remained significantly lower than during recovery in the passive and inactive modes (P < 0.05). No differences in either T(es) or T(sk) were observed among conditions. Given that MAP was higher during passive and active recovery modes than during inactive recovery suggests differences in CVC may be due to differences in baroreceptor unloading and not factors attributed to central command. However, differences in sweat rate may be influenced by factors such as central command and mechanoreceptor stimulation.

Effects of mode of exercise recovery on thermoregulatory and cardiovascular responses

To identify the effects of exercise recovery mode on cutaneous vascular conductance (CVC) and sweat rate, eight healthy adults performed two 15-min bouts of upright cycle ergometry at 60% of maximal heart rate followed by either inactive or active (loadless pedaling) recovery. An index of CVC was calculated from the ratio of laser-Doppler flux to mean arterial pressure. CVC was then expressed as a percentage of maximum (%max) as determined from local heating. At 3 min postexercise, CVC was greater during active recovery (chest: 40 +/- 3, forearm: 48 +/- 3%max) compared with during inactive recovery (chest: 21 +/- 2, forearm: 25 +/- 4%max); all P < 0.05. Moreover, at the same time point sweat rate was greater during active recovery (chest: 0.47 +/- 0.10, forearm: 0.46 +/- 0.10 mg x cm(-2) x min(-1)) compared with during inactive recovery (chest: 0.28 +/- 0.10, forearm: 0.14 +/- 0.20 mg x cm(-2) x min(-1)); all P < 0.05. Mean arterial blood pressure, esophageal temperature, and skin temperature were not different between recovery modes. These data suggest that skin blood flow and sweat rate during recovery from exercise may be modulated by nonthermoregulatory mechanisms and that sustained elevations in skin blood flow and sweat rate during mild active recovery may be important for postexertional heat dissipation.

A checkpointing–recovery scheme for Time Warp parallel simulation

This paper presents a checkpointing–recovery scheme for Time Warp parallel simulation. The scheme relies on a checkpointing protocol, namely mixed state saving, embedding both sparse and incremental state saving modes, and on a state recovery procedure embedding both forward and backward recovery modes. This scheme is a generalization of many previous solutions, which can be obtained as particular instances of it by selecting appropriate values for the checkpointing protocol parameters. We also present two regulating algorithms to adaptively tune the checkpointing protocol parameters, in order to make the protocol reacting to variable rollback behavior. A synthetic benchmark in several different configurations has been used for evaluating and comparing our scheme with previous solutions. The obtained data show that our solution allows faster execution and, in addition, keeps quite low the amount of memory used for recording state information; this allows the scheme to not adversely affect performance when memory is a critical resource.

Magnetic resonance imaging in diplegic form of cerebral palsy.

Eighteen children with diplegic form of cerebral palsy (CP) underwent magnetic resonance imaging (MRI) because of the enlarged occipital horns of both lateral ventricles found on previous computerized tomography (CT). In 16 of them squint was present. MRI in flow attenuated inversion recovery (FLAIR) and turbo spin echo (TSE) modes (T2 weighted images) best showed white matter lesions in occipital areas in all patients with squint, while no white matter changes could be detected in CT (in retrospect), thus proving the superiority of MRI in examining CP children. The authors postulate that the hemispheric occipital lesion causing impairment of visual co-ordination may result in squint.

The Barny Sentinel trawl-resistant ADCP bottom mount: design, testing, and application

A trawl-resistant bottom mount (TRBM) has been developed to meet the needs of long-term deployment of Acoustic Doppler Current Profilers (ADCPs) and Wave-Tide Gauges in water depths up to 300 m. This paper describes the unit's construction and operation together with practical lessons learned during development, testing, and use that can be applied to comparable platforms. The Barny Sentinel is derived from a larger version developed several years ago at SACLANT Center, now extensively redesigned to incorporate an RDI Sentinel ADCP and a Sea-Bird Wave-Tide Gauge. A concrete ring surrounding the fiberglass instrument housing serves as ballast and impact protection. Two independent recovery modes may be activated by acoustic commands, one of which can operate whether or not the platform is upright. Features have also been included to facilitate recovery by remotely operated underwater vehicle. A sending unit, temporarily attached during launch, provides real time information on platform depth and tilt, and confirms that the platform is properly positioned on the bottom before a launch commitment is made. A series of tests and applications have validated all basic functions and trawl resistance. Platform cost has been kept below that of the on-board instruments, while still maintaining the required high level of recoverability.