Short Rest Periods Research Articles

Comparison of stocking methods for beef production in northern Australia: seasonal diet quality and composition

Managing and measuring the grazing and nutrition of cattle are required to improve the productivity and profitability of beef businesses in northern Australia. The quality and composition of the diet selected by cattle grazing in three stocking methods (continuous, extensive rotation and intensive (cell) rotation) on nine commercial properties in Queensland were estimated using near infrared reflectance spectroscopy analyses of fresh faeces; 585 faecal samples were analysed between 2005 and 2009. Sites were in two regions (north and south Queensland) and on two vegetation communities, namely brigalow (Acacia harpophylla F. Muell. ex Benth.) on clay soils and eucalypts on light-textured soil types. Pastures were dominated by perennial sown exotic grass species, predominantly Cenchrus ciliaris L. (buffel grass) at five sites and Urochloa mosambicensis (Hack.) (Sabi grass) at one site, and by native perennial tussock grasses at three sites. Seasonal profiles of dietary crude protein, dry matter digestibility, faecal nitrogen concentration, proportion of non-grass, ratio of crude protein to digestibility and an estimate of liveweight gain are presented for each stocking method. Overall, dietary crude protein, digestibility, faecal nitrogen, the crude protein : digestibility ratio and liveweight gain were significantly higher for animals grazed continuously, with short rest periods, than for animals in extensive or intensive rotations. There was a significant interaction between stocking method and pasture growing conditions, measured as a simulated growth index, for dietary crude protein and faecal nitrogen. There was no difference between stocking methods during periods when the index was <0.2, indicating no pasture growth, but during periods of active growth (index >0.5), crude protein and faecal nitrogen were higher with continuous grazing than in the extensive and intensive rotations. For cattle producers considering alternative stocking methods, the results suggest they can obtain similar ecological responses under any of the three methods and diet quality will be higher during the pasture growing period in continuously grazed pastures.

Динамика параметров психофизиологических функций человека в условиях трансширотных перемещений

Adaptation is a fundamental property of organisms, which purpose is to keep quasi-attractors parameters within certain limits providing non equilibrium open systems in quasiattractor state. Parameter mismatch of functional systems, desynchronization of circadian rhythms, stability reduction of regulatory mechanisms in the conditions of the North are caused with extreme envi-ronmental parameters, chaotic oscillations of temperature and barometric modes, or socio-economic (information) changes. However, we can get the greatest expectations in this field by monitoring child population and older adults, as these are the most dangerous age groups in terms of sensitivity to ecological factors of Ugra. It is obvious that frequent vibrational motions of the state vector of the human organism do not allow it entering the stable quasi-attractor. For instance, long-term re-gimes of monotonous work, significant physical load or mental stress with short rest periods do not allow keeping the state vector of the human organism in quasi-attractors and accelerate the motion of quasi-attractor centers in the field of the mortal oscillatory rate.

Function of copulatory plugs in house mice: mating behavior and paternity outcomes of rival males

Polyandry is widespread across animal taxa, and subjects males to intense post-copulatory sexual selection which favors adaptations that enhance a male’s paternity success, either by decreasing the risk of sperm competition and/or by increasing the competitiveness of the ejaculate. Copulatory plugs deposited by males are thought to have evolved in the context of sperm competition. However, experimental studies that assess the function of copulatory plugs remain scarce. Moreover, most studies have used unnatural manipulations, such as ablating plug-producing male glands or interrupting copulations. Here, we investigated whether repeated ejaculation affects plug size in a mammalian model species, the house mouse. When males experience short periods of sexual rest we found that plug size decreased over repeated ejaculations so that time since last ejaculation can be applied as an approximation for plug size. We induced natural variation in plug size arising from variation in male sexual restedness, and investigated the behavior and paternity success of rival males. Male behavior in the offensive mating role (second) was influenced, albeit not significantly, by the sexual restedness of the first male-to-mate, and therefore the size of his plug. However, second males sired a significantly greater proportion of embryos when competing against a male that had recently mated compared to a male that had not. This supports a potential role of the plug in promoting a male's competitive fertilization success when remating occurs, which could be mediated both by delaying female remating and by ensuring efficient sperm transport through the female reproductive tract.

A Descending Resistance Sets Produces Greater Training Volume than a Constant Resistance Sets

PURPOSE:When an experienced resistance-trained individual performs multiple sets with a short rest period, such as 1 minute and 30 seconds between sets, the resistance must be reduced to maintain the same number of repetitions (reps) until fatigue. Otherwise, the number of reps will be reduced if the same resistance is used. There is no standard method for optimizing resistance to maximize training volume when using multiple sets with short rest periods. In this study, we hypothesized that a greater training volume (sets × reps × resistance) would be produced using a four week training method where resistance is decreased with each set (DR) compared to a four week CR method. In order to develop DR sets, we used the subject’s fatigue ratio (using an individualized regression equation) from a CR protocol where the number of repetitions declines with each set. METHODS: Ten male subjects (mean±SD, age = 30±5 yr, height = 175±5 cm, body mass = 78±4 kg, 1RM = 127±9 kg, weight training experience = 6±2 yr) completed pre and post training volume tests of 4 sets at 80% and 75% of their 1RM CR bench press. During these pre and post tests, four week muscular endurance intensities equivalent to 80% and 75% 1RM CR or DR bench press exercise trainings were performed in counterbalanced order. Data was analyzed using paired sample t-tests. RESULTS: There were greater increases with training volume (p < 0.05) when subjects trained with DR sets compared to training with CR sets after a four week training period for each condition (table 1). CONCLUSIONS: In males, a greater training volume is attained using a four week DR method based on subject’s fatigue ratio than when using a four week CR training method. This suggests that DR training may be more effective than CR training.Table 1: Training volumes (kg, sets × reps × resistance) completed during 4 set exercises.

Effects of Rest Period/Number of Reps in Arm Specific Resistance Exercise on Acute Hormonal Responses

PURPOSE: In the present study, we investigated how resistance exercises with different rest times affect local hormone production. To determine the local hormonal responses induced by resistance exercise (RE), we designed RE protocols targeting the biceps and triceps muscles only. We hypothesize that short rest periods with light-medium weight/high reps induce higher hormonal responses than long rest periods with heavy weight/ lower reps. METHODS: 7 male students (24–37 yrs) were divided into 2 groups. All participants performed 3 exercises for biceps and triceps, respectively. For each exercise the participants executed 3 sets, each set taken to failure, the rest period between sets and exercises was 30 sec in the first groups (Short rest group, S). The weight was a weight the participants could perform between 15–25 reps (50% 1RM). The second group (Long rest group, L) performed the same training protocol except for the rest period between sets and exercises which has been lengthened to 3 min and the weight which has been increased to a max of 6–8 reps (80% 1RM). Blood collection was conducted immediately before, immediately after, 15 min, 30 min and 60 min after the exercise session. Blood samples were then analyzed for testosterone, free testosterone, IGF-1 and GH. The experiment was conducted twice with a recovery period of 2 months in a cross-over fashion in order to obtain n=8 for each group, each participant executing both RE protocols. RESULTS: The S group showed a significantly greater hormonal increase immediately after RE only in GH (282%, p<0.05 vs. rest, p<0.05 vs. before) . RE induced no significant changes in other anabolic hormones (testosterone, free testosterone and IGF-1). CONCLUSION: Arm only exercises can induce important acute hormonal increases if conducted with high intensity (short rest, high reps).

Postoperative intervertebral stabilizing effect after cervical laminoplasty.

We previously demonstrated short length of rest with a cervical orthosis obtained a decreased tendency for neck or shoulder pain, neck stiffness, and impairment of cervical alignment after cervical laminoplasty. Postoperative maintenance of cervical motion may result in intervertebral instability and poor surgical outcomes. The purpose of this study was to compare the postoperative fusion rate, range of motion (ROM), vertebral listhesis, and surgical outcomes with the duration of rest with a cervical orthosis. We conducted cervical laminoplasty on 66 patients with spondylotic myelopathy. All patients were followed for at least two years. Patients remained in bed for two weeks and wore a cervical orthosis for eight weeks postoperatively, postoperative bed rest for seven days and use of an orthosis for four weeks, or postoperative bed rest for five days followed by use of an orthosis for two weeks were assigned. Long rest with a cervical orthosis produced multiple unions and limitation of cervical ROM, resulting in postoperative neck pain. Short rest maintained motion at multiple disc levels. There was no marked difference in neurogenic outcomes between short and long rest. A short rest period with a cervical orthosis is recommended to maintain cervical motion free from neck pain.

Early development and allometric growth patterns in ide Leuciscus idus (Linnaeus 1758)

Allometric growth and ontogeny were studied in ide Leuciscus idus (L.) reared in laboratory conditions from 0 to 30 days post hatching (DPH), to define important steps in the species’ early life history. Based on the external morphology, eleven different stages during the early development of ide were identified (ES9a – JS1a; ES – embryonic stage, JS – juvenile stage). After a short period of rest, hatched individuals were visual feeders with a pelagic life. Organogenesis and allometric changes indicated that development priorities concerned feeding efficiency, respiration efficiency and locomotion performances. Also concluded was that the gradual changes observed in body proportions (which occurred across a wide range of body lengths) reflect the absence of abrupt changes in the behaviour and habitat and may also be considered as a gradual adaptation to life in flowing water.

Dangerously Sleepy: Overworked Americans and the Cult of Manly Wakefulness by Alan Derickson (review)

Reviewed by: Dangerously Sleepy: Overworked Americans and the Cult of Manly Wakefulness by Alan Derickson Brigitte Steger Alan Derickson. Dangerously Sleepy: Overworked Americans and the Cult of Manly Wakefulness. Philadelphia: University of Pennsylvania Press, 2014. xiii + 224 pp. $49.95 (978-0-8122-4553-0). The fraught relationship between sleep and work in modern American history is the topic of this book, which focuses on “wakefulness as a measure of masculinity” (p. x) and the impact of working conditions on health (p. xi). In the first chapter, “Sleep is for Sissies,” men of achievement such as Benjamin Franklin, Thomas Edison, Charles Lindbergh, and Donald Trump cite a reduction in their sleeping hours not only as a reason for their success, but also as a measure of their self-discipline and virtuous work ethic. Derickson argues that “these iconic figures, along with many others, fashioned a tradition of heroic manly sleeplessness that valorized wakefulness” (p. 26). The second chapter argues that restrictions on night-time labor and the protection of workers’ rights to sleep in the United States were motivated mainly by the potential impact on other people rather than damage to the health of the workers themselves. As women played a vital role in ensuring the health of the future generation by bearing and raising children, they were more likely to be protected from (or restricted to) night-time work, whereas working hours for men were reduced only for the sake of public safety or greater efficiency for the employer. The three main chapters introduce case studies of shift workers in the steel industry, Pullman sleeping car porters, and long-haul truck drivers. Derickson discusses the struggle by the labor unions and individual workers for longer sleep breaks, and the resistance they encountered from employers. Steel production in America was characterized by long, irregular shift work and cramped housing conditions, which resulted in sleep disorders, exhaustion, on-the-job injuries, and alcoholism. With a seemingly inexhaustible pool of willing immigrants, steel industrialists felt little pressure to improve working conditions, despite pressure from social scientists. It was only in 1923 that the twelve-hour working day was abolished, due partly to the insight that better working conditions could lead to improved efficiency. From the outset in 1867, Pullman hired only African Americans as sleeping car porters, as he “considered former slaves particularly appropriate candidates for jobs involving … personal service” (p. 87). Pullman allowed his workers hardly any time for sleep, and even during their short rest periods they were required [End Page 130] to remain alert to the needs of the passengers. Unlike most workers groups that focused on public safety issues, the Brotherhood of Sleeping Car Porters included the effect of exhaustion on workers’ health in its fight for better conditions. Work regulations for truckers have remained essentially unchanged since the late 1930s with ten hours on and eight hours off the job (pp. 118–19). Despite recent medical studies that show the adverse health effect of these long and often drug-enhanced shifts, governments have been reluctant to improve their situation. The book reads fluently and provides interesting details of the struggle for work-time regulations for three groups of male workers that were under great pressure to curtail their sleep time. However, it would have been helpful if these cases had been compared with the same jobs in other countries and also related to the wider context of the work-sleep dynamic in mainstream jobs in the United States. Were these examples typical or exceptional in the workplace? Were they forerunners in the fight for workers’ rights? Did sleeping car attendants in other countries experience the same conditions as the Afro-American Pullman porters, or was it the result of a uniquely paternalistic policy? The lack of any discussion in the case studies of “the cult of manly wakefulness” as a potential cause for the “overworked American” is also disappointing. Pullman sleeping car porters were told by the brotherhood to stand up for their rights and “be a man” rather than being childishly servile, but no evidence is provided that indicates that lack of sleep was viewed as a sign of manliness. For truckers, working hours were considerably...

Extreme Conditioning Programs: Potential Benefits and Potential Risks.

CrossFit, Insanity, Gym Jones, and P90X are examples of extreme conditioning programs (ECPs). ECPs typically involve high-volume and high-intensity physical activities with short rest periods between movements and use of multiple joint exercises. Data on changes in fitness with ECPs are limited to CrossFit investigations that demonstrated improvements in muscle strength, muscular endurance, aerobic fitness, and body composition. However, no study has directly compared CrossFit or other ECPs to other more traditional forms of aerobic and resistance training within the same investigation. These direct comparisons are needed to more adequately evaluate the effectiveness of ECPs. Until these studies emerge, the comparisons with available literature suggest that improvements in CrossFit, in terms of muscular endurance (push-ups, sit-ups), strength, and aerobic capacity, appear to be similar to those seen in more traditional training programs. Investigations of injuries in ECPs are limited to two observational studies that suggest that the overall injury rate is similar to that seen in other exercise programs. Several cases of rhabdomyolysis and cervical carotid artery dissections have been reported during CrossFit training. The symptoms, diagnosis, and treatment of these are reviewed here. Until more data on ECPs emerge, physical training should be aligned with US Army doctrine. If ECPs are included in exercise programs, trainers should (1) have appropriate training certifications, (2) inspect exercise equipment regularly to assure safety, (3) introduce ECPs to new participants, (4) ensure medical clearance of Soldiers with special health problems before participation in ECPs, (4) tailor ECPs to the individual Soldier, (5) adjust rest periods to optimize recovery and reduce fatigue, (6) monitor Soldiers for signs of overtraining, rhabdomyolysis, and other problems, and (7) coordinate exercise programs with other unit training activities to eliminate redundant activities and minimize the risk of overuse injuries.

Massage induces an immediate, albeit short-term, reduction in muscle stiffness.

Using ultrasound shear wave elastography, the aims of this study were: (a) to evaluate the effect of massage on stiffness of the medial gastrocnemius (MG) muscle and (b) to determine whether this effect (if any) persists over a short period of rest. A 7-min massage protocol was performed unilaterally on MG in 18 healthy volunteers. Measurements of muscle shear elastic modulus (stiffness) were performed bilaterally (control and massaged leg) in a moderately stretched position at three time points: before massage (baseline), directly after massage (follow-up 1), and following 3 min of rest (follow-up 2). Directly after massage, participants rated pain experienced during the massage. MG shear elastic modulus of the massaged leg decreased significantly at follow-up 1 (-5.2 ± 8.8%, P = 0.019, d = -0.66). There was no difference between follow-up 2 and baseline for the massaged leg (P = 0.83) indicating that muscle stiffness returned to baseline values. Shear elastic modulus was not different between time points in the control leg. There was no association between perceived pain during the massage and stiffness reduction (r = 0.035; P = 0.89). This is the first study to provide evidence that massage reduces muscle stiffness. However, this effect is short lived and returns to baseline values quickly after cessation of the massage.

Effects of transport stress and rest before slaughter on blood parameters and meat quality of ducks

Zhu, Z., Chen, Y., Huang, Z., Zhang, Y., Xu, Q., Tong, Y., Zhai, F., Chang, G. and Chen, G. 2014. Effects of transport stress and rest before slaughter on blood parameters and meat quality of ducks. Can. J. Anim. Sci. 94: 595–600. Ducks have been transported to be slaughtered at centralized locations since the 2013 avian influenza A (H7N9) epidemics in China. It is unavoidable that a certain amount of stress will occur during the transportation. We investigated the effects of transport stress and rest before slaughter on blood parameters and meat quality in ducks. Pekin ducks (42 d old) were randomly divided into six groups. Each group had five replicates, with four ducks in each replicate. The experimental design included the variables transport time and rest time before slaughter. Transport distance categories were short-distance (1 h transport; n=20), medium-distance (2 h transport; n=20) and long-distance (3 h transport; n=20) transport. Rest time was categorized as short (0.5 h; n=20) or long (2 h; n=20) periods of rest. Blood samples and meat samples were collected after transport or after the post-transport rest period. Blood indicators (triiodothyronine, thyroxine, insulin, glutamic-pyruvic transaminase, aspartate transaminase, creatine kinase, and glutathione peroxidase) were measured using enzyme-linked immunosorbent assay (ELISA) kits. Meat quality characteristics (meat component, pH, malondialdehyde, and protein carbonyl) were also measured. Triiodothyronine, thyroxine, aminotransferase, glutamic-oxaloacetic transaminase, creatine kinase, glutathione peroxidase, pH, malondialdehyde, and protein carbonyl values changed significantly in ducks exposed to the medium-distance transport treatment. Stress indicators improved and meat quality returned to normal by the end of a 2-h pre-slaughter rest. These results indicate that a 2-h transport causes serious stress in ducks. A 2-h rest before slaughter mitigates these adverse effects.

Comparing the Thixotropic and Lightly Solidified Hardening Behavior of a Dredged Marine Clay

When a soil is disturbed upon remolding, it may lose part or all of its strength. As time passes, the structural arrangement of the soil particles would be restored to a stable form and the soil would regain hardness under constant volume and water content. The process is known as “thixotropic hardening”. On another note, dredged marine soils of the fine-grained type can be reused as a backfill material instead of being disposed to the open sea. The rest period required for the relocated soil to regain strength and stiffness, i.e. thixotropic hardening, needs to be estimated precisely. For this purpose, a study on the phenomena of strength and stiffness gain by a dredged marine clay was carried out. The strength and stiffness improvement with time was measured using the vane shear and fall cone tests respectively. The clay was remolded at different water contents in multiples of the soil’s liquid limit (LL), namely 0.75LL, 1.00LL and 1.25LL, in order to evaluate the effect of initial water content on thixotropic hardening. A separate series of samples were prepared with light solidification using cement, to examine the possibilities of enhancing the soil’s improvement in a shorter rest period. The results showed the dredged marine clay can potentially be used as a backfill material for reclamation works, with lower initial water content and light solidification contributing to accelerated better performance

The Contribution of Experimental in vivo Models to Understanding the Mechanisms of Adaptation to Mechanical Loading in Bone.

Changing loading regimens by natural means such as exercise, with or without interference such as osteotomy, has provided useful information on the structure:function relationship in bone tissue. However, the greatest precision in defining those aspects of the overall strain environment that influence modeling and remodeling behavior has been achieved by relating quantified changes in bone architecture to quantified changes in bones’ strain environment produced by direct, controlled artificial bone loading. Jiri Hert introduced the technique of artificial loading of bones in vivo with external devices in the 1960s using an electromechanical device to load rabbit tibiae through transfixing stainless steel pins. Quantifying natural bone strains during locomotion by attaching electrical resistance strain gages to bone surfaces was introduced by Lanyon, also in the 1960s. These studies in a variety of bones in a number of species demonstrated remarkable uniformity in the peak strains and maximum strain rates experienced. Experiments combining strain gage instrumentation with artificial loading in sheep, pigs, roosters, turkeys, rats, and mice has yielded significant insight into the control of strain-related adaptive (re)modeling. This diversity of approach has been largely superseded by non-invasive transcutaneous loading in rats and mice, which is now the model of choice for many studies. Together such studies have demonstrated that over the physiological strain range, bone’s mechanically adaptive processes are responsive to dynamic but not static strains; the size and nature of the adaptive response controlling bone mass is linearly related to the peak loads encountered; the strain-related response is preferentially sensitive to high strain rates and unresponsive to static ones; is most responsive to unusual strain distributions; is maximized by remarkably few strain cycles, and that these are most effective when interrupted by short periods of rest between them.

Diel activity patterns of Paradiplosis tumifex (Diptera: Cecidomyiidae) and its inquiline, Dasineura balsamicola (Diptera: Cecidomyiidae), within young balsam fir

AbstractField studies were carried out to assess diel activity patterns of the balsam gall midge, Paradiplosis tumifex Gagné (Diptera: Cecidomyiidae) in 2012, and its inquiline, Dasineura balsamicola (Lintner) (Diptera: Cecidomyiidae) in 2013, in a young balsam fir (Abies balsamea (Linnaeus) Miller) stand in New Brunswick, Canada. Both gallmaker and inquiline are most active during the afternoon/evening hours (17:00–22:00 hours). Male gallmaker activity was largely confined to the space below the crown and typically involved short periods of flight of &lt;30 seconds. Calling and mating by the gallmaker occurred at ground level and were followed by dispersal of females to the vegetative crown. Female gallmakers were typically observed in the tree crown beginning in early afternoon, with peak oviposition occurring between 20:00 and 21:00 hours. Female inquilines displayed similar activity patterns, although no calling or mating were observed. Moreover, inquiline flight and foraging for oviposition sites were more active than the gallmaker, with shorter rest periods and more buds visited than the gallmaker. Our results indicate that population monitoring should focus on female gallmakers as they fly during the evening. Also, before any treatment application, care should be taken to accurately identify the insects to ensure that the inquiline is not inadvertently killed.

Short rest periods between work shifts predict sleep and health problems in nurses at 1-year follow-up

ObjectivesWe investigated whether the number of work shifts separated by less than 11 hours (quick returns) at baseline (T1) could predict health problems in nurses at 1-year follow-up (T2).Methods1224 nurses...

Ultrahigh-Resolution Imaging of the Human Brain with Phase-Cycled Balanced Steady-State Free Precession at 7 T

The objectives of this study were to acquire ultra-high resolution images of the brain using balanced steady-state free precession (bSSFP) at 7 T and to identify the potential utility of this sequence. Eight volunteers participated in this study after providing informed consent. Each volunteer was scanned with 8 phase cycles of bSSFP at 0.4-mm isotropic resolution using 0.5 number of excitations and 2-dimensional parallel acceleration of 1.75 × 1.75. Each phase cycle required 5 minutes of scanning, with pauses between the phase cycles allowing short periods of rest. The individual phase cycles were aligned and then averaged. The same volunteers underwent scanning using 3-dimensional (3D) multiecho gradient recalled echo at 0.8-mm isotropic resolution, 3D Cube T2 at 0.7-mm isotropic resolution, and thin-section coronal oblique T2-weighted fast spin echo at 0.22 × 0.22 × 2.0-mm resolution for comparison. Two neuroradiologists assessed image quality and potential research and clinical utility. The volunteers generally tolerated the scan sessions well, and composite high-resolution bSSFP images were produced for each volunteer. Rater analysis demonstrated that bSSFP had a superior 3D visualization of the microarchitecture of the hippocampus, very good contrast to delineate the borders of the subthalamic nucleus, and relatively good B1 homogeneity throughout. In addition to an excellent visualization of the cerebellum, subtle details of the brain and skull base anatomy were also easier to identify on the bSSFP images, including the line of Gennari, membrane of Liliequist, and cranial nerves. Balanced steady-state free precession had a strong iron contrast similar to or better than the comparison sequences. However, cortical gray-white contrast was significantly better with Cube T2 and T2-weighted fast spin echo. Balanced steady-state free precession can facilitate ultrahigh-resolution imaging of the brain. Although total imaging times are long, the individually short phase cycles can be acquired separately, improving examination tolerability. These images may be beneficial for studies of the hippocampus, iron-containing structures such as the subthalamic nucleus and line of Gennari, and the basal cisterns and their contents.

The Effects of High Intensity Short Rest Resistance Exercise on Muscle Damage Markers in Men and Women

Within and between sexes, universal load prescription (as assigned in extreme conditioning programs) creates extreme ranges in individual training intensities. Exercise intensity has been proposed to be the main factor determining the degree of muscle damage. Thus, the purpose of this study was to examine markers of muscle damage in resistance-trained men (n = 9) and women (n = 9) from a high intensity (HI) short rest (SR) (HI/SR) resistance exercise protocol. The HI/SR consisted of a descending pyramid scheme starting at 10 repetitions, decreasing 1 repetition per set for the back squat, bench press, and deadlift, as fast as possible. Blood was drawn pre-exercise (pre), immediately postexercise (IP), 15 minutes postexercise (+15), 60 minutes postexercise (+60), and 24 hours postexercise (+24). Women demonstrated significant increases in interleukin 6 (IL-6; IP), creatine kinase (CK; +24), myoglobin (IP, +15, +60), and a greater relative increase when compared with men (+15, +60). Men demonstrated significant increases in myoglobin (IP, +15, +60, +24), IL-6 (IP, +15), CK (IP, +60, +24), and testosterone (IP, +15). There were significant sex interactions observed in CK (IP, +60, +24) and testosterone (IP, +15, +60, +24). Women completed the protocol faster (women: 34:04 ± 9:40 minutes, men: 39:22 ± 14:43 minutes), and at a slightly higher intensity (women: 70.1 ± 3.5%, men 68.8 ± 3.1%); however, men performed significantly more work (men: 14384.6 ± 1854.5 kg, women: 8774.7 ± 1612.7 kg). Overall, women demonstrated a faster inflammatory response with increased acute damage, whereas men demonstrated a greater prolonged damage response. Therefore, strength and conditioning professionals need to be aware of the level of stress imposed on individuals when creating such volitional high intensity metabolic type workouts and allow for adequate progression and recovery from such workouts.

Wakeful rest alleviates interference-based forgetting

Retroactive interference (RI)—the disruptive influence of events occurring after the formation of a new memory—is one of the primary causes of forgetting. Placing individuals within an environment that postpones interference should, therefore, greatly reduce the likelihood of information being lost from memory. For example, a short period of wakeful rest should diminish interference-based forgetting. To test this hypothesis, participants took part in a foreign language learning activity and were shown English translations of 20 Icelandic words for immediate recall. Half of the participants were then given an 8-min rest before completing a similar or dissimilar interfering distractor task. The other half did not receive a rest until after the distractor task, at which point interference had already taken place. All participants were then asked to translate the Icelandic words for a second time. Results revealed that retention was significantly worse at the second recall test, but being allowed a brief rest before completing the distractor task helped reduce the amount of forgetting. Taking a short, passive break can shield new memories from RI and alleviate forgetting.

Characterization of Microdamage Healing in Asphalt Concrete with a Smeared Continuum Damage Approach

The fatigue of asphalt concrete (AC) mixtures is a major source of distress in pavement structures. In most laboratory fatigue studies, testing is carried out by means of continuously repeating load cycles. However, under real traffic conditions, AC is subjected to a succession of load pulses as the traffic passes. Between these loads the material is not subjected to external forces and undergoes changes related to relaxation and healing, which together act to increase the overall fatigue life relative to what is observed under continuous loading. In the study reported in this paper, the effects of a rest period on the fatigue response in uniaxial, on-specimen, displacement-controlled loading was studied at 4.48C, 21.18C, and 388C. Loading consisted of a sinusoidal pulse–rest history with rest periods of 1, 5, or 10 s. Mixtures were used with the same aggregate structure and constituent materials but different asphalt and air void (AV) contents. It was found that the introduction of even short rest periods substantially improved the fatigue response of AC. A viscoelastic damage model for smeared healing was derived and characterized with the measured data. This model was compared with a damage-only continuum formulation and used to identify the impacts of healing, apart from any viscoelastic relaxation effects. It was found that greater AC and lower AV content yielded more favorable healing behaviors. The findings also suggested differences in the active healing mechanisms in pulse–rest and block–rest loading, typically used to study healing in AC. These differences are discussed.

Potencial climático para a produção de uvas em sistema de dupla poda anual no estado do Paraná

A cultura da videira tem potencial para produção contínua logo após pequeno período de descanso entre safras, porém os riscos climáticos podem limitar essa prática. O objetivo foi avaliar o potencial climático para o cultivo de duas safras anuais e a estimativa da severidade de míldio, em função de diferentes épocas de poda, e da exigência em graus-dia de diferentes genótipos de uvas (Vitis spp.), no estado do Paraná. Foram avaliados os riscos de geada, o balanço hídrico climatológico normal e a severidade potencial de ocorrência de míldio utilizando dados de 21 estações meteorológicas do Instituto Agronômico do Paraná. A ocorrência de geadas limita a época de cultivo da videira nas regiões centro, sul e leste. O excesso hídrico é observado em todo o estado. Genótipos que necessitam 1.800°C dia entre a poda e a colheita somente podem ser utilizados em sistema de dupla safra anual nas regiões mais quentes do estado. Não é possível a obtenção de duas safras anuais quando se utilizam genótipos de videiras que exigem mais de 2.000°C dia. Nas regiões mais frias, somente genótipos que necessitam 1.000 a 1.200°C dia podem ser utilizados. Em função do potencial de severidade do míldio, indica-se o cultivo de uvas rústicas ou americanas para as regiões centro, sul e leste, enquanto nas regiões sudoeste, oeste, norte e noroeste indica-se o cultivo das uvas finas ou europeias, porém sem descartar a necessidade de controle da doença nas fases fenológicas mais suscetíveis.