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Sedentary
Terms modified by Sedentary Selected AbstractsTower Climbing Exercise Started 3 Months After Ovariectomy Recovers Bone Strength of the Femur and Lumbar Vertebrae in Aged Osteopenic Rats,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2003Takuya Notomi Abstract To determine both the preventive and recovery effects of tower climbing exercise on mass, strength, and local turnover of bone in ovariectomized (OVX) rats, we carried out two experiments. In experiment I, 60 Sprague-Dawley rats, 12 months of age, were assigned to four groups: a Baseline Control, Sham-Operated Sedentary, OVX-Sedentary and OVX-Exercise rats. Rats voluntarily climbed a 200-cm tower to drink water from a bottle set at the top. At 3 months, OVX elevated both the femoral cortex and lumbar trabecular turnover, leading to a reduction in bone mass and strength. However, in OVX-Exercise rats, those values were maintained at the same level as in the Sham-Sedentary rats. Thus, the climbing exercise, started after 3 days of OVX, prevented OVX-induced cortical and trabecular bone loss by depressing turnover elevation. After confirming the preventive effect, we evaluated the recovery effect of exercise. In experiment II, 90 Sprague-Dawley rats, 12 months of age, were assigned to six groups: a Baseline control, two groups of Sham-Operated Sedentary and OVX-Sedentary, and OVX-Exercise rats. The exercise started 3 months after the OVX operation. At 3 months, OVX increased the trabecular bone formation rate and osteoclast surface, leading to a decrease in compressive strength. In the midfemur, the cross-sectional area, moment of inertia, and bending load values decreased. At 6 months, in the OVX-Exercise rats, the parameters of breaking load in both the lumbar and midfemur, lumbar bone mass, and the total cross-sectional area recovered to the same levels as those in the Sham-Sedentary rats. However, the cortical bone area did not recover. Periosteal bone formation increased, while endosteal bone formation decreased. These results showed that the climbing exercise had both a preventive and recovery effect on bone strength in OVX rats. In the mid-femur, effects on bone formation were site-specific, and the cross-sectional morphology was improved without an increase in cortical bone area, supporting cortical drift by mechanical stimulation. [source] Leisure-Time Physical Activity in Elementary Schools: Analysis of Contextual ConditionsJOURNAL OF SCHOOL HEALTH, Issue 10 2010Thomas L. McKenzie PHD BACKGROUND: Little is known about children's leisure-time physical activity (PA) at school and how it is associated with contextual variables. The purpose of this study was to objectively assess children's voluntary PA during 3 daily periods and examine modifiable contextual factors. METHODS: We conducted SOPLAY (System for Observing Play and Leisure Activity in Youth) observations before school, during recess, and at lunchtime in 137 targeted activity areas in 13 elementary schools over 18 months. During observations, each child was coded as Sedentary, Walking, or Vigorous, and simultaneous entries were made for area characteristics (accessibility, usability, presence of supervision, loose equipment, and organized activities). Logistic regression analysis was used to test associations between PA and area characteristics. RESULTS: Assessors made 2349 area visits and observed 36,995 children. Boys had more moderate-to-vigorous physical activity (MVPA; 66.2 vs 60.0%, p < .001) and more vigorous PA (29.8 vs 24.6%; p < .001) than girls. Areas were typically accessible and usable, but provided organized activities infrequently (16.5%). Odds of engaging in MVPA were greater during lunch and recess than before school and in areas with play equipment (p < .05). CONCLUSIONS: Children accrued a substantial amount of voluntary PA during leisure time at school. Their PA would likely be increased if school playground equipment was more readily available and if supervisors were taught to provide active games and promote PA rather than suppress it. [source] Macroecology of a host-parasite relationshipECOGRAPHY, Issue 1 2000Caryn C. Vaughn The larvae of freshwater mussels are obligate ectoparasites on fishes while adults are sedentary and benthic. Dispersal of mussels is dependent on the movement of fish hosts, a regional process, but growth and reproduction should be governed by local processes. Thus, mussel assemblage attributes should be predictable from the regional distribution and abundance of fishes. At a broad spatial scale in the Red River drainage, USA, mussel species richness and fish species richness were positively associated; maximum mussel richness was limited by fish richness, but was variable beneath that constraint. Measured environmental variables and the associated local fish assemblages each significantly accounted for the regional variation in mussel assemblages. Furthermore, mussel assemblages showed strong spatial autocorrelation. Variation partitioning revealed that pure fish effects accounted for 15.4% of the variation in mussel assemblages; pure spatial and environmental effects accounted for 16.1% and 7.8%, respectively. Shared variation among fish, space and environmental variables totaled 40%. Of this shared variation, 36.8% was associated with the fish matrix. Thus, the variation in mussel assemblages that was associated with the distribution and abundance of fishes was substantial (> 50%), indicating that fish community structure is an important determinant of mussel community structure. Although animals commonly disperse plants and, thus, influence the structure of plant communities, our results show a strong macroecological association between two disparate animal groups with one strongly affecting the assemblage structure of the other. [source] Movements of Murray cod (Maccullochella peelii peelii) in a large Australian lowland riverECOLOGY OF FRESHWATER FISH, Issue 4 2009J. D. Koehn Abstract,,, This study of Murray cod (Maccullochella peelii peelii) movements in a large lowland river in south-eastern Australia indicated that the species was not sedentary, but undertook complex movements that followed a seasonal pattern. While there were sedentary periods with limited home ranges and high site fidelity, Murray cod also under took larger movements for considerable portions of the year coinciding with its spawning schedule. This generally comprised movements (up to 130 km) from a home location in late winter and early spring to a new upstream position, followed by a rapid downstream migration typically back to the same river reach. Timing of movements was not synchronous amongst individuals and variation in the scale of movements was observed between individuals, fish size, original location and years. [source] Population ecology of cave armoured catfish, Ancistrus cryptophthalmus Reis 1987, from central Brazil (Siluriformes: Loricariidae)ECOLOGY OF FRESHWATER FISH, Issue 2 2007E. Trajano Abstract,,, The population ecology of Ancistrus cryptophthalmus (Reis 1987) was studied by mark,recapture technique in caves from the São Domingos karst area, State of Goiás, northeastern Brazil. Total population sizes estimated for Angélica and Passa Três Caves were 20,000 and 1000 individuals, respectively. Densities around 1.0 individuals per m2 in Angélica, Bezerra and São Vicente I Streams, and 0.6 individuals per m2 in the smaller Passa Três Stream may be considered high for cavefish standards, as well as for epigean loricariids. As expected for benthic grazers, cave catfish are highly sedentary. The distribution of size classes did not differ among caves and within the same cave throughout the studied dry seasons; on the contrary, the condition factor decreased throughout this period probably because of the progressive depletion of organic matter available as food. Low proportions of mature individuals, low growth rates (average = 0.5 mm month,1) with cases of negative growth and high longevities (8,10 years) point to a precocial lifestyle, typical of troglobitic species. [source] Exercise training attenuates ageing-induced BKCa channel downregulation in rat coronary arteriesEXPERIMENTAL PHYSIOLOGY, Issue 6 2010Sulayma Albarwani Physical inactivity and ageing are widely recognized as risk factors for development of coronary artery disease. One of the characteristic changes that occurs in aged coronary artery is downregulation of their large-conductance voltage- and calcium-activated K+ (BKCa) channels. In this study, we investigated the effects of moderate exercise training (ET) on the activity of BKCa channels in coronary arteries of aged rats. Old Fischer 344 rats (23,26 months old) were randomly assigned to sedentary (O-SED, n= 24) or exercise-trained groups (O-ET, n= 28). The O-ET rats underwent a progressive treadmill exercise-training programme for 60 min day,1, 5 days week,1 for 12 weeks. Young animals were used for comparison. Coronary arteries were mounted on a wire myograph, and contractions in response to 1, 10, 30, 50 and 100 nmol l,1 iberiotoxin were compared. Iberiotoxin (100 nmol l,1) contracted coronary arteries of young, O-SED and O-ET rats by 115 ± 14, 36 ± 5.6 and 61 ± 5% of 5-hydroxytryptamine-induced contractions, respectively. Patch-clamp studies revealed a larger magnitude of BKCa current in young (104 ± 15.6 pA pF,1) compared with O-ET (44 ± 9 pA pF,1) and least in O-SED coronary smooth muscle cells (8.6 ± 2 pA pF,1). Western immunoblotting was performed to study expression levels of BKCa channel proteins. The , and ,1 subunits of the BKCa channel were reduced by 40 ± 3.5 and 30 ± 2.6%, respectively, in coronary arteries of old compared with young rats, and ET attenuated this reduction in expression level to 28 ± 2 and 12 ± 4%, respectively. Our results showed that ageing was associated with a reduction in BKCa channels, and ET partly reversed this reduction. We conclude that low-intensity ET may be beneficial in restoring age-related decline in coronary vasodilatory properties mediated by BKCa channels. [source] Exercise-induced neuronal plasticity in central autonomic networks: role in cardiovascular controlEXPERIMENTAL PHYSIOLOGY, Issue 9 2009Lisete C. Michelini It is now well established that brain plasticity is an inherent property not only of the developing but also of the adult brain. Numerous beneficial effects of exercise, including improved memory, cognitive function and neuroprotection, have been shown to involve an important neuroplastic component. However, whether major adaptive cardiovascular adjustments during exercise, needed to ensure proper blood perfusion of peripheral tissues, also require brain neuroplasticity, is presently unknown. This review will critically evaluate current knowledge on proposed mechanisms that are likely to underlie the continuous resetting of baroreflex control of heart rate during/after exercise and following exercise training. Accumulating evidence indicates that not only somatosensory afferents (conveyed by skeletal muscle receptors, baroreceptors and/or cardiopulmonary receptors) but also projections arising from central command neurons (in particular, peptidergic hypothalamic pre-autonomic neurons) converge into the nucleus tractus solitarii (NTS) in the dorsal brainstem, to co-ordinate complex cardiovascular adaptations during dynamic exercise. This review focuses in particular on a reciprocally interconnected network between the NTS and the hypothalamic paraventricular nucleus (PVN), which is proposed to act as a pivotal anatomical and functional substrate underlying integrative feedforward and feedback cardiovascular adjustments during exercise. Recent findings supporting neuroplastic adaptive changes within the NTS,PVN reciprocal network (e.g. remodelling of afferent inputs, structural and functional neuronal plasticity and changes in neurotransmitter content) will be discussed within the context of their role as important underlying cellular mechanisms supporting the tonic activation and improved efficacy of these central pathways in response to circulatory demand at rest and during exercise, both in sedentary and in trained individuals. We hope this review will stimulate more comprehensive studies aimed at understanding cellular and molecular mechanisms within CNS neuronal networks that contribute to exercise-induced neuroplasticity and cardiovascular adjustments. [source] Voracious invader or benign feline?FISH AND FISHERIES, Issue 3 2009A review of the environmental biology of European catfish Silurus glanis in its native, introduced ranges Abstract A popular species for food and sport, the European catfish (Silurus glanis) is well-studied in its native range, but little studied in its introduced range. Silurus glanis is the largest-bodied freshwater fish of Europe and is historically known to take a wide range of food items including human remains. As a result of its piscivorous diet, S. glanis is assumed to be an invasive fish species presenting a risk to native species and ecosystems. To assess the potential risks of S. glanis introductions, published and ,grey' literature on the species' environmental biology (but not aquaculture) was extensively reviewed. Silurus glanis appears well adapted to, and sufficiently robust for, translocation and introduction outside its native range. A nest-guarding species, S. glanis is long-lived, rather sedentary and produces relatively fewer eggs per body mass than many fish species. It appears to establish relatively easily, although more so in warmer (i.e. Mediterranean) than in northern countries (e.g. Belgium, UK). Telemetry data suggest that dispersal is linked to flooding/spates and human translation of the species. Potential impacts in its introduced European range include disease transmission, hybridization (in Greece with native endemic Aristotle's catfish [Silurus aristotelis]), predation on native species and possibly the modification of food web structure in some regions. However, S. glanis has also been reported (France, Spain, Turkmenistan) to prey intensively on other non-native species and in its native Germany to be a poor biomanipulation tool for top-down predation of zooplanktivorous fishes. As such, S. glanis is unlikely to exert trophic pressure on native fishes except in circumstances where other human impacts are already in force. In summary, virtually all aspects of the environmental biology of introduced S. glanis require further study to determine the potential risks of its introduction to novel environments. [source] A comparison of no-take zones and traditional fishery management tools for managing site-attached species with a mixed larval poolFISH AND FISHERIES, Issue 3 2007William J F Le Quesne Abstract No-take zones (NTZs) can generate higher larval production by sessile, sedentary and site-attached species per unit area than in exploited areas, and may increase recruitment and yield compared to status quo management. Whilst NTZs may be considered an essential part of optimal management, few studies have specifically compared the effects of NTZs with those of correctly applied gear and effort controls. A yield-per-recruit (YPR) population model, based on the sedentary abalone Haliotis laevigata, was used to compare the effects of management by minimum landing size (MLS), effort limitation and NTZs, either singularly or in combination. Initially, a minimum basic YPR model was used. Three additional assumptions were sequentially added to the model to see if they affected conclusions drawn from the model. The additional assumptions were the inclusion of: (i) a length,fecundity relationship; (ii) an age-dependent natural mortality function; and (iii) mortality of undersized individuals due to fishery operations. In the absence of undersized mortality caused by fishing, under virtually all conditions the population is best managed with a combination of MLS and effort control, without any NTZs. For simulations that included mortality of undersized individuals in the fished area, under nearly all circumstances NTZs were considered an essential part of optimal fishery management, and management incorporating NTZs greatly increased the sustainable yield that could be taken. [source] Dispersal and migration of juvenile African Black Oystercatchers Haematopus moquiniIBIS, Issue 3 2003Philip A. R. Hockey African Black Oystercatchers Haematopus moquini are sedentary as adults. However, colour-ringing of more than 700 juveniles has revealed complex post-fledging movements that vary geographically. Young from the western part of the breeding range either remain within 150 km of their natal site or migrate 1500,2000 km to one of five discrete nursery areas on the Namib Desert coast of central and northern Namibia, and southern Angola. These nurseries all lie north of the species' breeding range. We calculate that 36,46% of all juveniles born in South Africa migrate to nurseries. Birds return to their natal sites from nurseries at 2,3 years old, but never migrate again. Juveniles from the eastern part of the range undertake ,diffusion dispersal', regularly up to 1000 km, but these journeys mostly end within the breeding range, where there are no nurseries. Very few eastern birds reach nurseries. There is no evidence that movements of western birds are density-dependent responses to hatching date, but long-distance migrants are significantly heavier as chicks than are short-distance dispersers. We hypothesize that a genetic basis exists to these movements, possibly triggered by body condition, that could account not only for the highly dichotomous behaviour of western birds, but also for the intermediate behaviour of eastern birds. [source] Movement characteristics of the Scarce Blue-tailed Damselfly, Ischnura pumilioINSECT CONSERVATION AND DIVERSITY, Issue 1 2010KATHERINE A. ALLEN Abstract., 1. The Scarce Blue-tailed Damselfly, Ischnura pumilio, is threatened in the UK and exists in small, transient colonies. Consequently, little is known about its dispersal characteristics. This study investigates movement in two contrasting habitats with the aim of informing conservation management on a landscape scale. 2. Mark-release-recapture studies were performed at an established colony in the New Forest and a smaller population in the Red River valley in southern England. A total of 2304 individuals was marked. 3. Ischnura pumilio was found to be exceptionally sedentary. Mean gross lifetime movement was 56 m and 43% of individuals moved <50 m in their lifetime. Movements over 150 m were very rare. Maximum lifetime movement was 1165 m. As such, I. pumilio is the most sedentary odonate studied in the UK to date. 4. Movement was inversely density dependent, which has important conservation implications if individuals attempt to emigrate from small populations because of low density. The presence of parasitic mites (Hydryphantes sp.) significantly increased movement distance. 5. Ischnura pumilio had a low dispersal probability compared to other damselflies. As the smallest British odonate, this is in keeping with the relationship between size and dispersal found across taxa. 6. Ischnura pumilio has been regarded as a ,wandering opportunist' due to its tendency to appear in locations far from known sites. However, this study suggests that long range movement rarely occurs from prime habitat that is maintained in an early successional stage. This has implications for the conservation of the species in the UK. [source] Heat reversal of activity-based anorexia: Implications for the treatment of anorexia nervosaINTERNATIONAL JOURNAL OF EATING DISORDERS, Issue 7 2008Emilio Gutierrez PhD Abstract Objective: Activity-based anorexia (ABA) provides an animal model of anorexia nervosa (AN). In this model, rats given restricted access to food but unrestricted access to activity wheels, run excessively while reducing food intake, lose a sizeable percentage of body weight, become hypothermic, and can fail to recover unless removed from these conditions. Method: Once rats had lost 20% of body weight under standard ABA conditions, they were assigned to one of two ambient temperature (AT) conditions. Results: Increased AT reduced running rates and led to weight gain in active rats. The effect of increasing AT on food intake was dependent on whether the rats were sedentary or active. Although warming reduced food intake in the sedentary rats their body weight remained stable, whereas in active rats increased AT did not reduce food intake and weight gain gradually rose. Conclusion: From a translational perspective, these findings offer a fresh perspective to the disorder, and underscore the need for further studies to assess the effects of heat treatment in patients as an innovative adjunctive treatment for anorexia nervosa. © 2008 by Wiley Periodicals, Inc. Int J Eat Disord 2008 [source] Cardiovascular Exercise Training Extends Influenza Vaccine Seroprotection in Sedentary Older Adults: The Immune Function Intervention TrialJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 12 2009Jeffrey A. Woods PhD OBJECTIVES: To determine whether cardiovascular exercise training resulted in improved antibody responses to influenza vaccination in sedentary elderly people who exhibited poor vaccine responses. DESIGN: Single-site randomized parallel-arm 10-month controlled trial. SETTING: University of Illinois at Urbana-Champaign. PARTICIPANTS: One hundred forty-four sedentary, healthy older (69.9 ± 0.4) adults. INTERVENTIONS: Moderate (60,70% maximal oxygen uptake) cardiovascular exercise was compared with flexibility and balance training. MEASUREMENTS: The primary outcome was influenza vaccine response, as measured according to hemagglutination inhibition (HI) anti-influenza antibody titer and seroprotective responses (HI titer ,40). Secondary measures included cardiovascular fitness and body composition. RESULTS: Of the 160 participants enrolled, 144 (90%) completed the 10-month intervention with excellent compliance (,83%). Cardiovascular, but not flexibility, exercise intervention resulted in improvements in indices of cardiovascular fitness, including maximal oxygen uptake. Although not affecting peak (e.g., 3 and 6 weeks) postvaccine anti-influenza HI titers, cardiovascular exercise resulted in a significant increase in seroprotection 24 weeks after vaccination (30,100% dependent on vaccine variant), whereas flexibility training did not. CONCLUSION: Participants randomized to cardiovascular exercise experienced improvements in influenza seroprotection throughout the entire influenza season, whereas those in the balance and flexibility intervention did not. Although there were no differences in reported respiratory tract infections, the exercise group exhibited reduced overall illness severity and sleep disturbance. These data support the hypothesis that regular endurance exercise improves influenza vaccine responses. [source] Pilot Test of an Attribution Retraining Intervention to Raise Walking Levels in Sedentary Older AdultsJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 11 2007Catherine A. Sarkisian MD OBJECTIVES: To pilot test a new behavioral intervention to increase walking in sedentary older adults. DESIGN: Pre,post community-based pilot study. SETTING: Three senior centers in greater Los Angeles. PARTICIPANTS: Forty-six sedentary adults aged 65 and older. INTERVENTION: At four weekly 1-hour group sessions held at the senior centers, a trained health educator applied a theoretically grounded, standardized "attribution retraining" curriculum developed by a multidisciplinary team of investigators. Participants were taught that becoming sedentary is not inevitable with aging and that older adults should attribute being sedentary to modifiable attributes rather than to old age. A 1-hour exercise class including strength, endurance, and flexibility training followed each weekly attribution retraining session. MEASUREMENTS: Change from baseline in steps per week recorded using a digital pedometer was measured after 7 weeks. Age expectations (measured using the Expectations Regarding Aging-38 survey, a previously tested instrument on which higher scores indicate that the participant expects high functioning with aging and lower scores indicate that the participant expects physical and mental decline) and health-related quality of life were measured using in-person interviews. RESULTS: Mean steps per week increased from 24,749 to 30,707, a 24% increase,equivalent to 2.5 miles (2-sided t -test P=.002). Age expectation scores increased 30% (P<.001), and the changes in age expectations and steps per week correlated (correlation coefficient=0.39, P=.01). Participants experienced improved mental health,related quality of life (P=.049) and reported less difficulty with activities of daily living (P=.04). More than 50% of participants reported improvements in pain, energy level, and sleep quality. CONCLUSION: In this small pre,post community-based pilot study, a structured attribution retraining curriculum accompanied by a weekly exercise class was associated with increased walking levels and improved quality of life in sedentary older adults. Attribution retraining deserves further investigation as a potential means of increasing physical activity in sedentary older adults. [source] A quantitative study of day,night changes in the spatial distribution of insects in a stony streamJOURNAL OF ANIMAL ECOLOGY, Issue 1 2002J. M. Elliott Summary 1As many invertebrates are nocturnal, their spatial distribution may change from day to night. This behavioural aspect of their population dynamics has been ignored, but is now examined for the first time by testing the hypotheses: (i) a power function was a suitable model for the spatial distribution of common species of Ephemeroptera, Plecoptera and Trichoptera in a stony stream; (ii) the spatial distribution varied between species but was similar within species for larvae greater and smaller than half-size; (iii) diurnal and nocturnal spatial distributions were significantly different for each species. To ensure that the conclusions were consistent, large samples (n = 30) were taken near midday and midnight in April, June and November over 4 years. 2Twenty,one species were taken in sufficient numbers for the analyses; seven species were too sparse to be included. The first hypothesis was supported. A power function, relating spatial variance (s2) to mean (m), was an excellent fit in all the analyses (P < 0·001, r2 > 0·95), i.e. the spatial variance was density,dependent. The power b, often used as an ,index of aggregation', varied in the range 0·88,2·50. 3Most analyses supported the second hypothesis. For four species, the difference between the two size groups was just significant (P < 0·05), but was due to inadequate data for three species. Large larvae of the fourth species, the caddis Odontocerum albicorne, were less aggregated than small larvae at night, and were the only group with a b -value less than one. 4The third hypothesis was partially supported. The distribution did not change significantly (P > 0·05) for nine species; five burrowers in gravel, moss or mud, two highly mobile predators, one sedentary, case,building, Trichoptera species, and one net,spinning Trichoptera species. Aggregation was reduced significantly (P < 0·001) at night for four species, all case,building Trichoptera larvae. Aggregation increased significantly (P < 0·001) at night, except at low densities, for the remaining eight species, one being a nocturnal predator and the others being herbivorous species; all occurred frequently in night samples of invertebrate drift. Day,night changes in spatial distribution were therefore an essential part of the behavioural dynamics of 12 of the 21 species, and should be investigated in other species, including terrestrial species. [source] Daily pattern of some fatty acids in the athletic horseJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1 2009G. Piccione Summary In the sport field, non-esterified fatty acids (NEFA) are important for the physical performance during the aerobic exercise of short intensity and long duration. In man, rat, goat and in the sedentary horse studies on the chronometabolism showed the presence of a circadian rhythm of the plasmatic concentration of NEFA while data for the athletic horse are lacking. To define a chronogram helpful for a specific planning and the differentiation of the training programmme in the athletic horse, the circadian pattern of some fatty acids (NEFA, palmitic, stearic, oleic, linoleic and linolenic acids) was studied in five Sella Italiana horses. These horses trained following a daily model of activity consisting of walk, trot, gallop and jump of obstacles of different heights. Blood samples were collected from the jugular vein every 4 h, starting at 08:00 hours, for 2 days to assess the concentrations of total NEFA (by spectrophotometry), palmitic, stearic, oleic, linoleic and linolenic acids (by gas chromatography). anova for repeated measures showed a statistical significant effect of the time of the day in NEFA, oleic and linolenic acids. The application of the periodic model showed the periodic pattern of NEFA, oleic, linoleic and linolenic acids. Acrophases were in the afternoon for all parameters. The results obtained showed a different trend of the circadian pattern of the studied parameters in the athletic horse than in the sedentary one because the physical activity and the post-prandial metabolism acted as zeitgebers. [source] The Effects of Physical Activity Enjoyment on Sedentary Older Adults' Physical Activity Attitudes and Intentions,JOURNAL OF APPLIED BIOBEHAVIORAL RESEARCH, Issue 1 2006Kathleen A. Martin Ginis This pilot study examined the effects of 2 types of acute physical activity bouts on enjoyment and subsequent change in attitudes and intentions regarding physical activity. Participants were 41 sedentary, older men and women (M age = 75.4 years) randomized to a single bout of walking plus either (a) 2 sets of a resistance-training circuit performed on weight machines (Weights); or (b) 1 set of the resistance circuit plus 1 set of strength-based activities of daily living (Weights + ADL). The Weights condition enjoyed their bout more, and enjoyment mediated subsequent changes in attitudes. Both conditions increased their physical activity intentions. However, contrary to the tenets of the theory of planned behavior, increased intentions were not mediated by improved attitudes toward physical activity. These findings suggest that single bouts of activity can differentially affect sedentary older adults' thoughts toward being active in their daily lives. [source] Spatial synchrony in field vole Microtus agrestis abundance in a coniferous forest in northern England: the role of vole-eating raptorsJOURNAL OF APPLIED ECOLOGY, Issue 2000S.J. Petty 1.,The regional synchrony hypothesis (RSH) states that synchrony in microtine abundance over large geographical areas is caused by nomadic avian predators that specialize on small mammals for food. This has proved a difficult hypothesis to test because experiments at an appropriate scale are almost impossible. 2.,We used the decline of the most abundant, nomadic vole-eating raptors in an extensive conifer forest in northern England (Kielder Forest) as a natural experiment to evaluate their influence on synchronizing voles at different spatial scales. Field vole populations fluctuated on a 3,4-year cycle of abundance, similar to the periodicity in central Fennoscandia. 3.,Over a 23-year period, the combined numbers and density of kestrels and short-eared owls significantly declined. If these raptors were responsible for synchronizing vole abundance, the decline should have been associated with a decrease in synchrony. We could find no change in synchrony during the period of the greatest decline in kestrel and short-eared owl numbers (1980,97). 4.,In Kielder, vole abundance has been shown to change in a wave-like manner, with synchrony in the direction of the wave being 5,10-fold smaller than that reported in Fennoscandia. Tawny owls are sedentary and the most abundant vole-eating raptor in our study area, and might have an equalizing influence on vole abundance over smaller areas if they foraged in a density-dependent manner and responded functionally to increasing vole density. If this was the case, spatial variability in vole density should have been less in occupied than unoccupied owl territories, especially in years of low vole density when owls could take a larger proportion of the standing crop of voles. Even though tawny owls caught a significant proportion of the vole population, we could find no difference in variation in vole density between owl territories that were unoccupied, occupied with no breeding attempt, or occupied with a successful breeding attempt. 5.,We conclude that the small-scale synchrony in field vole abundance is unlikely to be caused by avian predators. Instead, it is more likely to be related to the pattern of clear-cutting that has developed in Kielder, which restricts vole dispersal. If this assumption is correct, we would predict more widespread synchrony in vole abundance in first-generation forests when extensive areas are planted over short periods of time, and this is supported by anecdotal evidence. These conclusions indicate that foresters may be able to manipulate the spatial dynamics of voles and vole predators by varying patch sizes within forests. [source] Synopsis of biological, fisheries and aquaculture-related information on mulloway Argyrosomus japonicus (Pisces: Sciaenidae), with particular reference to AustraliaJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2008V. Silberschneider Summary Argyrosomus japonicus is a member of the family Sciaenidae, which are commonly known as drums and croakers. A. japonicus occurs in estuarine and nearshore Pacific Ocean and Indian Ocean waters surrounding Australia, Africa, India, Pakistan, China, Korea and Japan. The biology of A. japonicus is relatively well studied in South Africa, and more recently studied in Australia, but no information is readily available from other areas of its distributional range. The early life history distribution of A. japonicus may differ among regions, with their distribution in estuaries linked to salinity, turbidity, freshwater flows and depth of water. Studies in South Africa and Australia found that juvenile fish grow rapidly, attaining 35 cm TL in 1 year and 87,90 cm TL in 5 years. Sexual maturity also differs among regions and is attained at 2,3 years of age and >50 cm in eastern Australia, 5,6 years of age and >80 cm TL in western Australia and southern Africa. The maximum reported length and age of A. japonicus is 175 cm and 42 years, respectively. Spawning most likely occurs in nearshore coastal waters although there is evidence to suggest that it may also occur in the lower reaches of estuaries. Time of spawning varies among geographic localities and is probably linked to water temperature and oceanography. Juvenile fish (<2 years) appear to be relatively sedentary, but sub-adults and adults can move relatively long distances (>200 km) and such movements may be linked to pre-spawning migrations. A. japonicus is important in many recreational and commercial fisheries, but like other sciaenids, is prone to overfishing. It is classified as recruitment overfished in South Africa and overfished in eastern Australia. Although much research has been done to minimize the capture of juveniles in Australian prawn-trawl fisheries, greater protection of spawners and improved fishing practices to enhance survival of discarded juveniles, particularly from prawn trawling, may be required. An aquaculture industry is developing for A. japonicus in Australia and preliminary research on the impacts and success of re-stocking wild populations has begun in an attempt to arrest the apparent decline in populations. [source] Occurrence and life history correlates of vocal duetting in North American passerinesJOURNAL OF AVIAN BIOLOGY, Issue 1 2008Lauryn Benedict Vocal duetting, where two birds produce temporally coordinated vocalizations, has been reported in a taxonomically and geographically diverse set of avian species. Researchers have suggested a number of potential correlates of duetting, including long term monogamy, year-round territory defense and sexual plumage monomorphism. Because the majority of duetting species are tropical, they have been the focus of the most comprehensive studies to date. There is, therefore, a real need for data regarding avian duets in temperate species. I used the recently completed Birds of North America species reports to examine the frequency, evolutionary origins and potential life history correlates of duetting behavior in North American passerines. "Duetting" behavior was reported in 7% of species from 12 avian families, likely representing 17 separate evolutionary origins. Duetting species showed apparent long term monogamy and year-round territoriality at frequencies more than double those of non-duetting passerines: 65% of duetting species were long term monogamous, compared to 27% of non-duetting species, and 50% of duetting species defended the same territory throughout the year, compared with only 11% of non-duetting species. Duetting and non-duetting species showed statistically indistinguishable frequencies of sexual plumage monomorphism. Comparative analyses of duetting species and their sister taxa revealed that the shift to duetting is accompanied by a gain of long term monogamy and year-round territoriality more often than it is associated with a loss of those traits. This study provides intriguing summary evidence that selective factors promoting duetting may be associated with a sedentary, monogamous lifestyle, and may operate similarly across taxonomic groups. Furthermore, vocal duetting may be considerably more common among temperate-zone species than previously recognized. [source] Heel pad thickness and athletic activity in healthy young adults: A sonographic study,JOURNAL OF CLINICAL ULTRASOUND, Issue 5 2006Murat Uzel MD Abstract Purpose. The aim of this study was to investigate the sonographic changes of heel fat pad thickness and compressibility index in healthy young adults in relation to level of athletic activity. Materials and Methods. One hundred ten young adults (55 women and 55 men) with a body mass index between 18.5 and 24.9 were divided into 3 groups according to their athletic activity level: group 1, sedentary (n = 50); group 2, athletic activity <7 hours/week (n = 30); and group 3, athletic activity ,7 hours/week (n = 30). The loaded heel pad thickness (LHPT) and unloaded heel pad thickness (ULHPT) were measured via sonography, and the heel pad compressibility index (HPCI) was calculated. Results. The mean values of ULHPT, LHPT, and HPCI in group 1 were similar to those of group 2 (p > 0.05) and group 3 (p > 0.05). The mean values of ULHPT, LHPT, and HPCI were similar in the left and right feet in the 3 groups (p > 0.05). There was no correlation between level of athletic activity and ULHPT, LHPT, or HPCI. Conclusions. The heel pad thickness and HPCI of individuals engaging in athletic activity up to an average of 11 hours/week were similar to those of sedentary individuals. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound 34:231,236, 2006 [source] Effect of wave exposure dynamics on gut content mass and growth of young-of-the-year fishes in the littoral zone of lakesJOURNAL OF FISH BIOLOGY, Issue 7 2010S. Stoll Total length, body mass and gut content mass of young-of-the-year (YOY) perch Perca fluviatilis, dace Leuciscus leuciscus and bleak Alburnus alburnus were recorded over the summer of 2006 at three littoral sites at Upper Lake Constance. In P. fluviatilis and L. leuciscus, gut content mass correlated positively with wave-induced energy flux (EF) of the respective site and sampling day, while no correlation of gut content mass with EF was found in A. alburnus. It was assumed that benthivorous P. fluviatilis and L. leuciscus profited from suspended or uncovered benthic food items generated by wave action at sites and periods with high EF. Alburnus alburnus, in contrast, feeding mainly on zooplankton in upper parts of the water column, could not profit from increased EF. In P. fluviatilis, increased gut content mass during periods of high EF resulted in higher growth rates. For L. leuciscus, no real growth rates in local fish populations could be determined, as individuals were less sedentary, and when increased growth occurred at sites during the periods of high EF, migration of fish levelled out the resulting size differences within few days. The results of this study show that dynamic habitat variables affect site profitability in the littoral zone of lakes, especially in benthivorous fishes. Therefore, dynamic habitat variables should be considered in addition to fixed habitat properties in analyses of habitat choice of fishes in the littoral zone of lakes. [source] Identifying facilitators and barriers to physical activity for adults with Down syndromeJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 9 2010J. Mahy Abstract Background Adults with Down syndrome are typically sedentary, and many do not participate in the recommended levels of physical activity per week. The aim of this study was to identify the facilitators and barriers to physical activity for this group. Method Semi-structured interviews were conducted to elicit the views of adults with Down syndrome and their support people about what factors facilitate physical activity and what factors are barriers to activity. A sample of 18 participants (3 men, 15 women) was recruited through two agencies providing services for adults with disabilities; six participants were adults with Down syndrome and 12 participants were support people (four were parents of adults with Down syndrome and eight participants were employed by day programmes attended by the adults with Down syndrome). The interviews were recorded, transcribed verbatim and independently coded by two researchers. Results Three themes around facilitators to physical activity were identified: (1) support from others; (2) that the physical activity was fun or had an interesting purpose; and (3) routine and familiarity. Three themes around barriers were also identified: (1) lack of support; (2) not wanting to engage in physical activity; and (3) medical and physiological factors. Conclusions The results suggest that support people play a key role, both as facilitators and barriers, in the participation by adults with Down syndrome in physical activity. Many of the barriers and facilitators of activity for adults with Down syndrome indentified are similar to those reported for adults without impairment. Our findings are also consistent with established theories in the field of health behaviour change. [source] Computational Network Model Prediction of Hemodynamic Alterations Due to Arteriolar Remodeling in Interval Sprint Trained Skeletal MuscleMICROCIRCULATION, Issue 3 2007Kyle W. Binder ABSTRACT Objectives: Exercise training is known to enhance skeletal muscle blood flow capacity, with high-intensity interval sprint training (IST) primarily affecting muscles with a high proportion of fast twitch glycolytic fibers. The objective of this study was to determine the relative contributions of new arteriole formation and lumenal arteriolar remodeling to enhanced flow capacity and the impact of these adaptations on local microvascular hemodynamics deep within the muscle. Methods: The authors studied arteriolar adaptation in the white/mixed-fiber portion of gastrocnemius muscles of IST (6 bouts of running/day; 2.5 min/bout; 60 m/min speed; 15% grade; 4.5 min rest between bouts; 5 training days/wk; 10 wks total) and sedentary (SED) control rats using whole-muscle Microfil casts. Dimensional and topological data were then used to construct a series of computational hemodynamic network models that incorporated physiological red blood cell distributions and hematocrit and diameter dependent apparent viscosities. Results: In comparison to SED controls, IST elicited a significant increase in arterioles/order in the 3A through 6A generations. Predicted IST and SED flows through the 2A generation agreed closely with in vivo measurements made in a previous study, illustrating the accuracy of the model. IST shifted the bulk of the pressure drop across the network from the 3As to the 4As and 5As, and flow capacity increased from 0.7 mL/min in SED to 1.5 mL/min in IST when a driving pressure of 80 mmHg was applied. Conclusions: The primary adaptation to IST is an increase in arterioles in the 3A through 6A generations, which, in turn, creates an approximate doubling of flow capacity and a deeper penetration of high pressure into the arteriolar network. [source] Decreased Arteriolar Sensitivity to Shear Stress in Adult Rats is Reversed by Chronic Exercise ActivityMICROCIRCULATION, Issue 2 2002Dong Sun M.D., Ph.D. Objective: We tested the hypothesis that the decline in endothelium-dependent arteriolar dilation in adult rats is reversed by chronic exercise activity. Methods: Rats were divided into young (8,10 weeks)-sedentary (SEDY), adult (29,32 weeks)-sedentary (SEDA), and adult-exercised (EXA, treadmill exercise for 18,20 weeks) groups. Responses of isolated arterioles (,50 µm at 80 mm Hg) of gracilis muscle were assessed to increases in perfusate flow and vasoactive agents. Results: With no differences in basal tone, maximal flow-induced dilations were not different between arterioles of SEDY and SEDA rats (71 ± 2 and 72 ± 2% of passive diameter, respectively), yet the sensitivity of arterioles to shear stress (WSS50) was significantly less in SEDA than in SEDY rats (35 ± 4 vs. 23 ± 3 dyne/cm2, respectively). In vessels of EXA rats, maximal flow-induced dilation was significantly augmented (88 ± 2% of passive diameter) and WSS50 (15 ± 1 dyn/cm2) was significantly reduced. Dilation to acetylcholine was enhanced in arterioles of EXA, whereas dilation to sodium nitroprusside was not different in vessels of the three groups. Conclusion: Chronic exercise activity reverses age related reduction in sensitivity of arterioles to increases in wall shear stress. [source] Time and space in the Sri Lanka-Tamil diasporaNATIONS AND NATIONALISM, Issue 2 2001Øivind Fuglerud Based upon fieldwork in Sri Lanka and among Tamil migrants in Norway, this article discusses the relationship between space, time and national identity. The author argues that in the Sri Lanka-Tamil diaspora one finds two different conceptions of Tamil culture, the ,traditional' and the ,revolutionary'. The first expresses a space-time relationship that is nomadic and grounded in heritage; the second one is sedentary and historicist. The latter serves as a basis for Tamil separatism, the first does not. By propagating the ,revolutionary' model of culture, with its particular understanding of space and time, the Tamil separatist movement Liberation Tigers of Tamil Eelam (LTTE) has adopted viewpoints that throughout this century have fuelled the nationalism of the Sinhalese majority in Sri Lanka. The author argues that instead of explaining social change historically, which is one trend within anthropological theory today, anthropologists should concentrate on exploring under which conditions historical explanations are seen as more valid than their alternatives. [source] Physical activity, food intake, and body weight regulation: insights from doubly labeled water studiesNUTRITION REVIEWS, Issue 3 2010Klaas R Westerterp Body weight and energy balance can be maintained by adapting energy intake to changes in energy expenditure and vice versa, whereas short-term changes in energy expenditure are mainly caused by physical activity. This review investigates whether physical activity is affected by over- and undereating, whether intake is affected by an increase or a decrease in physical activity, and whether being overweight affects physical activity. The available evidence is based largely on studies that quantified physical activity with doubly labeled water. Overeating does not affect physical activity, while undereating decreases habitual or voluntary physical activity. Thus, it is easier to gain weight than to lose weight. An exercise-induced increase in energy requirement is typically compensated by increased energy intake, while a change to a more sedentary routine does not induce an equivalent reduction of intake and generally results in weight gain. Overweight and obese subjects tend to have similar activity energy expenditures to lean people despite being more sedentary. There are two ways in which the general population trend towards increasing body weight can be reversed: reduce intake or increase physical activity. The results of the present literature review indicate that eating less is the most effective method for preventing weight gain, despite the potential for a negative effect on physical activity when a negative energy balance is reached. [source] Interventions for preventing obesity in childhood.OBESITY REVIEWS, Issue 3 2001A systematic review Abstract Background The prevalence of obesity and overweight is increasing worldwide. Obesity in children impacts on their health in both short- and long-term. Obesity prevention strategies are poorly understood. Objective To assess the effectiveness of interventions designed to prevent obesity in childhood. Search strategy Electronic databases were searched from January 1985 to October 1999. Selection criteria Data from randomized control trials and non-randomized trials with concurrent control group were included. A priori, studies with follow up of 1 year minimum were selected however, this was subsequently amended to include studies with a minimum follow up of three months. Data collection & analysis Two reviewers independently extracted data and assessed study quality. Main results Seven studies were included, three long-term (>1 years) and four short-term (>3 months and <1 years). The studies included were diverse in terms of study design and quality, target population, theoretical underpinning of intervention approach, and outcome measures. As such, it was not appropriate to combine study findings using statistical methods. Conclusions Two of the long-term studies (one focused on dietary education and physical activity vs. control, and the other only on dietary education vs. control), resulted in a reduction in the prevalence on obesity, but the third, which focused on dietary education and physical activity, found no effect. Of the four short-term studies, three focused simply on physical activity/reduction of sedentary behavious vs. control. Two of these studies resulted in a reduction in the prevalence of obesity in intervention groups compared with control groups, and another study found a non-significant reduction. The fourth study focused on dietary education and physical activity, and did not find an effect on obesity, but did report a reduction in fat intake. Overall, the findings of the review suggest that currently there is limited quality data on the effectiveness of obesity prevention programmes and as such no generalizable conclusions can be drawn. The need for well-designed studies that examine a range of interventions remains a priority. [source] Variability of limb muscle size in young menAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2010Taku Wakahara The purpose of this study was to determine the interindividual variability of the upper and lower limb muscle size in young men. Subjects were 655 Japanese men aged 18,39 years. They were sedentary and mildly to highly active individuals, including college athletes of various sports. Muscle thicknesses at each of the anterior and posterior portions of the upper arm, thigh, and lower leg were measured using B-mode ultrasonography. Interindividual variability of muscle thickness was evaluated by coefficients of variation (CVs). The CVs of muscle thicknesses were found to be in the order of upper arm posterior (17.7%), thigh anterior (14.8%), thigh posterior (12.6%), upper arm anterior (12.2%), lower leg anterior (9.8%), and lower leg posterior (9.4%). The CVs were significantly different between each pair of measurement sites except for those of upper arm anterior-thigh posterior and lower leg anterior-posterior. These differences remain significant even when the muscle thicknesses were normalized to the segment length. The observed differences in the size variability can be interpreted as muscle-related differences in hypertrophic responsiveness to resistance training. The muscle-dependent size variability may be related to the differences in the fiber-type composition and/or muscle usage in daily life among examined muscle groups. Am. J. Hum. Biol. 2010. © 2009 Wiley-Liss, Inc. [source] Testosterone and energetics in wild chimpanzees (Pan troglodytes schweinfurthii)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 2 2005Martin N. Muller Abstract Ovarian function in female hominoids is sensitive to both energy flux and energy balance, resulting in a reduced probability of conception during periods when a successful reproductive outcome is less likely. However, the extent to which energetic factors constrain gonadal function in male hominoids is not clear. We examined the effects of both acute and chronic variation in energy availability on urinary testosterone (T) levels in adult male chimpanzees. Acute changes in energy availability, which were assayed by means of observational data on feeding behavior, did not result in decreased T production for 11 individuals at Kibale National Park, Uganda. Chronic energy shortages, on the other hand, may be associated with lower T levels in this population. Adult males in Kibale (n=11), who maintain suboptimal access to energy, exhibit significantly lower urinary T levels than males in captivity (n=11), who are more sedentary and better fed. These results suggest that data on hormonal function in captive chimpanzees should be interpreted with caution because individuals may produce T at levels well above those that are typical in the wild. They also suggest that short-term variations in T levels in male hominoids are more likely to be explained by social factors than by energetic ones. Am. J. Primatol. 66:119,130, 2005. © 2005 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||