EVOLUTION, Issue 8 2008
Samantha E. Forde
Coevolutionary interactions are thought to play a crucial role in diversification of hosts and parasitoids. Furthermore, resource availability has been shown to be a fundamental driver of species diversity. Yet, we still do not have a clear understanding of how resource availability mediates the diversity generated by coevolution between hosts and parasitoids over time. We used experiments with bacteria and bacteriophage to test how resources affect variation in the competitive ability of resistant hosts and temporal patterns of diversity in the host and parasitoid as a result of antagonistic coevolution. Bacteria and bacteriophage coevolved for over 150 bacterial generations under high and low-resource conditions. We measured relative competitive ability of the resistant hosts and phenotypic diversity of hosts and parasitoids after the initial invasion of resistant mutants and again at the end of the experiment. Variation in relative competitive ability of the hosts was both time- and environment-dependent. The diversity of resistant hosts, and the abundance of host-range mutants attacking these phenotypes, differed among environments and changed over time, but the direction of these changes differed between the host and parasitoid. Our results demonstrate that patterns of fitness and diversity resulting from coevolutionary interactions can be highly dynamic. [source]

CONCORDANCE OF THE CIRCADIAN CLOCK WITH THE ENVIRONMENT IS NECESSARY TO MAXIMIZE FITNESS IN NATURAL POPULATIONS

EVOLUTION, Issue 4 2008
Kevin J. Emerson
The ubiquity of endogenous, circadian (daily) clocks among eukaryotes has long been held as evidence that they serve an adaptive function, usually cited as the ability to properly time biological events in concordance with the daily cycling of the environment. Herein we test directly whether fitness is a function of the matching of the period of an organism's circadian clock with that of its environment. We find that fitness, measured as the per capita expectation of future offspring, a composite measure of fitness incorporating both survivorship and reproduction, is maximized in environments that are integral multiples of the period of the organism's circadian clock. Hence, we show that organisms require temporal concordance between their internal circadian clocks and their external environment to maximize fitness and thus the long-held assumption is true that, having evolved in a 24-h world, circadian clocks are adaptive. [source]

ABSOLUTE FITNESS, RELATIVE FITNESS, AND UTILITY

EVOLUTION, Issue 12 2007
H. Allen Orr
It is well known that (1) natural selection typically favors an allele with both a large mean fitness and a small variance in fitness; and (2) investors typically prefer a portfolio with both a large mean return and a small variance in returns. In the case of investors, this mean,variance trade-off reflects risk aversion; in the case of evolution, the mathematics is straightforward but the result is harder to intuit. In particular, it is harder to understand where, in the mathematics of natural selection, risk aversion arises. Here I present a result that suggests a simple answer to this question. Although my answer is essentially identical to one offered previously, my path to it differs somewhat from previous approaches. Some may find this new approach easier to intuit. [source]

THE FITNESS EFFECT OF MUTATIONS ACROSS ENVIRONMENTS: A SURVEY IN LIGHT OF FITNESS LANDSCAPE MODELS

EVOLUTION, Issue 12 2006
Guillaume Martin
Abstract The fitness effects of mutations on a given genotype are rarely constant across environments to which this genotype is more or less adapted, that is, between more or less stressful conditions. This can have important implications, especially on the evolution of ecological specialization. Stress is thought to increase the variance of mutations' fitness effects, their average, or the number of expressed mutations. Although empirical evidence is available for these three mechanisms, their relative magnitude is poorly understood. In this paper, we propose a simple approach to discriminate between these mechanisms, using a survey of empirical measures of mutation effects in contrasted environments. This survey, across various species and environments, shows that stress mainly increases the variance of mutations effects on fitness, with a much more limited impact on their average effect or on the number of expressed mutations. This pattern is consistent with a simple model in which fitness is a Gaussian function of phenotypes around an environmentally determined optimum. These results suggest that a simple, mathematically tractable landscape model may not be quantitatively as unrealistic as previously suggested. They also suggest that mutation parameter estimates may be strongly biased when measured in stressful environments. [source]

LOCAL HETEROZYGOSITY-FITNESS CORRELATIONS WITH GLOBAL POSITIVE EFFECTS ON FITNESS IN THREESPINE STICKLEBACK

EVOLUTION, Issue 8 2006
Mélissa Lieutenant-Gosselin
Abstract The complex interactions between genetic diversity and evolution have important implications in many biological areas including conservation, speciation, and mate choice. A common way to study these interactions is to look at heterozygosity-fitness correlations (HFCs). Until recently, HFCs based on noncoding markers were believed to result primarily from global inbreeding effects. However, accumulating theoretical and empirical evidence shows that HFCs may often result from genes being linked to the markers used (local effect). Moreover, local effect HFCs could differ from global inbreeding effects in their direction and occurrence. Consequently, the investigation of the structure and consequences of local HFCs is emerging as a new important goal in evolutionary biology. In this study of a wild threespine stickleback (Gasterosteus aculeatus) population, we first tested the presence of significant positive or negative local effects of heterozygosity at 30 microsatellites loci on five fitness components: survival, mating success, territoriality, length, and body condition. Then, we evaluated the direction and shape of total impact of local HFCs, and estimated the magnitude of the impacts on fitness using regression coefficients and selection differentials. We found that multilocus heterozygosity was not a reliable estimator of individual inbreeding coefficient, which supported the relevance of single-locus based analyses. Highly significant and temporally stable local HFCs were observed. These were mainly positive, but negative effects of heterozygosity were also found. Strong and opposite effects of heterozygosity are probably present in many populations, but may be blurred in HFC analyses looking for global effects only. In this population, both negative and positive HFCs are apparently driving mate preference by females, which is likely to contribute to the maintenance of both additive and nonadditive genetic variance. [source]

ASSORTATIVE MATING FOR FITNESS AND THE EVOLUTION OF RECOMBINATION

EVOLUTION, Issue 7 2006
Alistair Blachford
Abstract To understand selection on recombination, we need to consider how linkage disequilibria develop and how recombination alters these disequilibria. Any factors that development of disequilbria, including nonrandom mating, can potentially change selectio on recombination. Assortative mating is known to affect linkage disequilbria but its effect on the evolution of recombination have not been previously studied. Given that assortative arise indirectly via a number of biologically realistic scenarios, it is plausible that weak assortative mating occurs across a diverse set of taxa. Using a modifier model, we examine how assortative mating for fitness affects the evolution of recombination under two evolutionary scenarios: selective sweeps and mutation-selection balance. We find there is no net effect of assortative mating during a selective sweep. In contrast, assortative mating could have a large effect on recombination when deleterious alleles are maintained at mutation-selection balance but only if assortative mating is sufficiently strong. Upon considering reasonable values for the number of loci affecting fitness components, the strength of selection, and the mutation rate, we conclude that the correlation in fitness between mates is unlikely to be sufficiently high for assortative mating to affect the evolution of recombination in most species. [source]

TOWARD A REALISTIC MODEL OF MUTATIONS AFFECTING FITNESS

EVOLUTION, Issue 3 2003
Peter D. Keightley
Abstract Analysis of a recent mutation accumulation (MA) experiment has led to the suggestion that as many as one-half of spontaneous mutations in Arabidopsis are advantageous for fitness. We evaluate this in the light of data from other MA experiments, along with molecular evidence, that suggest the vast majority of new mutations are deleterious. [source]

THE ECOLOGY AND GENETICS OF FITNESS IN CHLAMYDOMONAS.

EVOLUTION, Issue 1 2002
VIII.
Abstract According to classical evolutionary theory, sexual recombination can generate the variation necessary to adapt to changing environments and thereby confer an evolutionary advantage of sexual over asexual reproduction. Using the green alga, Chlamydomonas reinhardtii, we investigated the effect of a single sexual episode on adaptation of heterotrophic growth on different carbon sources. In an initial mixture of isolates, sex was induced and the resulting offspring constituted the sexual populations, along with any unmated vegetative cells; the unmated mixture of isolates represented the asexual populations. Mean and variance in division rates (i.e., fitness) were measured four times during approximately 50 generations of vegetative growth in the dark on all possible combinations of four carbon sources. Consistent with effects of recombination of epistatic genes in linkage disequilibrium, sexual populations initially had a higher variance in fitness, but their mean fitness was lower than that of asexual populations, possibly due to recombinational load. Subsequently, fitness of sexual populations exceeded that of asexual ones, but finally they regained parity in both mean and variance of fitness. Although recombination was not more effective on more complex substrates, these results generally support the idea that sex can accelerate adaptation to novel environments. [source]

Fitness and body size in mature odonates

ECOLOGICAL ENTOMOLOGY, Issue 2 2000
Natalia Sokolovska
Summary The relationship between body size and fitness components in odonates was examined using a meta-analysis of 33 published studies. There was a positive and significant overall effect of body size on mating rate and lifetime mating success among males. There was also a weaker but still significant positive effect of body size on survivorship of males. The relationship between body size, mating rate, longevity, and lifetime mating success differed significantly between males of territorial and nonterritorial species. The effect of body size was significant for all fitness components in territorial species but significant only for longevity and lifetime mating success in nonterritorial species. Effect sizes appeared to be strongest on longevity in both sexes, and on male mating rate in territorial species. Other effect sizes, even when significant, were small. Despite a much smaller data set, female fitness also increased significantly with body size. Both clutch size and longevity showed a significant positive relationship with body size. These results suggest that there is a general fitness benefit to large size in odonates. Nevertheless, significant heterogeneity is apparent in this effect, which can be attributed to sex, mating system, and fitness component. Finally, these analyses point to inadequacies in the current data that need further study before the potentially rich patterns in size effects on fitness can be explored more thoroughly. [source]

Fitness versus fatness: Moving beyond weight loss in nonalcoholic fatty liver disease,,

HEPATOLOGY, Issue 1 2010
Nathan A. Johnson
The rapid emergence of nonalcoholic fatty liver disease (NAFLD) as a cause of both liver-related morbidity and mortality and cardiometabolic risk has led to the search for effective lifestyle strategies to reduce liver fat. Lifestyle intervention comprising dietary restriction in conjunction with increased physical activity has shown clear hepatic benefits when weight loss approximating 3%-10% of body weight is achieved. Yet, the poor sustainability of weight loss challenges the current therapeutic focus on body weight and highlights the need for alternative strategies for NAFLD management. Epidemiologic data show an independent relationship between liver fat, physical activity, and fitness, and a growing body of longitudinal research demonstrates that increased physical activity participation per se significantly reduces hepatic steatosis and serum aminotransferases in individuals with NAFLD, independent of weight loss. Mechanistic insights to explain this interaction are outlined, and recommendations for the implementation of lifestyle intervention involving physical activity are discussed. In light of the often poor sustainability of weight loss strategies, and the viability of physical activity therapy, clinicians should assess physical fitness and physical activity habits, educate patients on the benefits of fitness outside of weight loss, and focus on behavior change which promotes physical activity adoption. (HEPATOLOGY 2010) [source]

Association Between Fitness and Changes in Body Composition and Muscle Strength

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 2 2010
George A. Kuchel, [see editorial comments by Drs. Gustavo Duque, pp 37
OBJECTIVES: To examine the association between physical fitness, assessed according to ability and time to complete a 400-m walk, on changes in body composition and muscle strength over a 7-year period. DESIGN: Prospective observational cohort study. SETTING: Memphis, Tennessee, and Pittsburgh, Pennsylvania. PARTICIPANTS: Two thousand nine hundred forty-nine black and white men and women aged 70 to 79 participating in the Health, Aging and Body Composition Study. MEASUREMENTS: Body composition (fat and bone-free lean mass) was assessed using dual-energy X-ray absorptiometry in Years 1 to 6 and 8. Knee extension strength was measured using isokinetic dynamometry and grip strength using isometric dynamometry in Years 1, 2, 4, 6, and 8. RESULTS: Less fit people weighed more and had a higher total percentage of fat and a lower total percentage of lean mass than very fit men and women at baseline (P<.001). Additionally, the least fit lost significantly more weight, fat mass, and lean mass over time than the very fit (all P<.01). Very fit people had the highest grip strength and knee extensor strength at baseline and follow-up; decline in muscle strength was similar in every fitness group. CONCLUSION: Low fitness in old age was associated with greater weight loss and loss of lean mass than with high fitness. Despite having lower muscle strength, the rate of decline in the least fit persons was similar to that in the most fit. In clinical practice, a long-distance walk test as a measure of fitness might be useful to identify people at risk for these adverse health outcomes. [source]

Prediction of Cardiorespiratory Fitness in Older Men Infected with the Human Immunodeficiency Virus: Clinical Factors and Value of the Six-Minute Walk Distance

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 11 2009
Krisann K. Oursler MD
OBJECTIVES: To investigate factors related to cardiorespiratory fitness in older human immunodeficiency virus (HIV)-infected patients and to explore the utility of 6-minute walk distance (6-MWD) in measuring fitness. DESIGN: Cross-sectional study in clinic-based cohort. SETTING: Veterans Affairs Medical Center, Baltimore, Maryland. PARTICIPANTS: Forty-three HIV-infected men, median age 57 (range 50,82), without recent acquired immunodeficiency syndrome,related illness and receiving antiretroviral (ARV) therapy. MEASUREMENTS: Peak oxygen utilization (VO2peak) according to treadmill graded exercise testing, 6-MWD, grip strength, quadriceps maximum voluntary isometric contraction, cross-sectional area, muscle quality, and muscle adiposity. RESULTS: There was a moderate correlation between VO2peak (mean ± SD; 18.4 ± 5.6 mL/kg per minute) and 6-MWD (514 ± 91 m) (r=0.60, P<.001). VO2peak was lower in subjects with hypertension (16%, P<.01) and moderate anemia (hemoglobin 10,13 gm/dL; 15%, P=.09) than in subjects without these conditions. CD4 cell count (median 356 cells/mL, range 20,1,401) and HIV-1 viral load (84% nondetectable) were not related to VO2peak. Among muscle parameters, only grip strength was an independent predictor of VO2peak. Estimation of VO2peak using linear regression, including age, 6-MWD, grip strength, and hypertension as independent variables, explained 61% of the variance in VO2peak. CONCLUSION: Non-AIDS-related comorbidity predicts cardiorespiratory fitness in older HIV-infected men receiving ARV therapy. The 6-MWD is a valuable measure of fitness in this patient population, but a larger study with diverse subjects is needed. [source]

Clinical Utility of Office-Based Cognitive Predictors of Fitness to Drive in Persons with Dementia: A Systematic Review

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 12 2006
Frank J. Molnar MDCM
OBJECTIVES: To perform a systematic review of evidence available regarding in-office cognitive tests that differentiate safe from unsafe drivers with dementia. DESIGN: A comprehensive literature search of multiple databases including Medline, CINAHL, PsychInfo, AARP Ageline, and Sociofile from 1984 to 2005 was performed. This was supplemented by a search of Current Contents and a review of the bibliographies of all relevant articles. SETTING: English prospective cohort, retrospective cohort, and case-control studies that used accepted diagnostic criteria for dementia or Alzheimer's disease and that employed one of the primary outcomes of crash, simulator assessment, or on-road assessment were included. PARTICIPANTS: Two reviewers. MEASUREMENTS: The reviewers independently assessed study design, main outcome of interest, cognitive tests, and population details and assigned a Newcastle-Ottawa quality assessment rating. RESULTS: Sixteen articles met the inclusion criteria. Tests recommended by guidelines (e.g., the American Medical Association (AMA) and Canadian Medical Association guidelines) for the assessment of fitness to drive did not demonstrate robustly positive findings (e.g., Mini-Mental State Examination, Trails B) or were not evaluated in any of the included studies (e.g., Clock Drawing). Fifteen studies did not report any cutoff scores. CONCLUSION: Without validated cutoff scores, it is impossible to employ tests in a standardized fashion in front-line clinical settings. This study identified a research gap that will prevent the development of evidence-based guidelines. Recommendations to address this gap are that driving researchers routinely perform cutoff score analyses and that stakeholder organizations (e.g., AMA, American Geriatrics Society) sponsor consensus fora to review driving research methodologies. [source]

Estimating Cardiorespiratory Fitness in Well-Functioning Older Adults: Treadmill Validation of the Long Distance Corridor Walk

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 1 2006
Eleanor M. Simonsick PhD
Objectives: To determine criterion validity of the 400-m walk component of the Long Distance Corridor Walk (LDCW) and develop equations for estimating peak oxygen consumption (VO2) from 400-m time and factors intrinsic to test performance (e.g., heart rate (HR) and systolic blood pressure (SBP) response) in older adults. Design: Cross-sectional validation study. Setting: Gerontology Research Center, National Institute on Aging, Baltimore, Maryland. Participants: Healthy volunteers (56 men and 46 women) aged 60 to 91 participating in the Baltimore Longitudinal Study of Aging between August 1999 and July 2000. Measurements: The LDCW, consisting of a 2-minute walk followed immediately by a 400-m walk "done as quickly as possible" over a 20-m course was administered the day after maximal treadmill testing. HR and SBP were measured before testing and at the end of the 400-m walk. Weight, height, activity level, perceived effort, and stride length were also acquired. Results: Peak VO2 ranged from 12.2 to 31.1 mL oxygen/kg per minute, and 400-m time ranged from 2 minutes 52 seconds to 6 minutes 18 seconds. Correlation between 400-m time and peak VO2 was ,0.79. The estimating equation from linear regression included 400-m time (partial coefficient of determination (R2)=0.625), long versus short stride (partial R2=0.090), ending SBP (partial R2=0.019), and a correction factor for fast 400-m time (<240 seconds; partial R2=0.020) and explained 75.5% of the variance in peak VO2 (correlation coefficient=0.87). Conclusion: A 400-m walk performed as part of the LDCW provides a valid estimate of peak VO2 in older adults. Incorporating low-cost, safe assessments of fitness in clinical and research settings can identify early evidence of physical decline and individuals who may benefit from therapeutic interventions. [source]

Relative Fitness and Frailty of Elderly Men and Women in Developed Countries and Their Relationship with Mortality

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 12 2005
Arnold Mitnitski PhD
Objectives: To investigate the relationship between accumulated health-related problems (deficits), which define a frailty index in older adults, and mortality in population-based and clinical/institutional-based samples. Design: Cross-sectional and cohort studies. Setting: Seven population-based and four clinical/institutional surveys in four developed countries. Participants: Thirty-six thousand four hundred twenty-four people (58.5% women) aged 65 and older. Measurements: A frailty index was constructed as a proportion of all potential deficits (symptoms, signs, laboratory abnormalities, disabilities) expressed in a given individual. Relative frailty is defined as a proportion of deficits greater than average for age. Measures of deficits differed across the countries but included common elements. Results: In each country, community-dwelling elderly people accumulated deficits at about 3% per year. By contrast, people from clinical/institutional samples showed no relationship between frailty and age. Relative fitness/frailty in both sexes was highly correlated (correlation coefficient >0.95, P<.001) with mortality, although women, at any given age, were frailer and had lower mortality. On average, each unit increase in deficits increased by 4% the hazard rate for mortality (95% confidence interval=0.02,0.06). Conclusion: Relative fitness and frailty can be defined in relation to deficit accumulation. In population studies from developed countries, deficit accumulation is robustly associated with mortality and with age. In samples (e.g., clinical/institutional) in which most people are frail, there is no relationship with age, suggesting that there are maximal values of deficit accumulation beyond which survival is unlikely. [source]

Fitness and Cognition: Encouraging Findings and Methodological Considerations for Future Work

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 4 2003
Eleanor M. Simonsick PhD
No abstract is available for this article. [source]

Perceived Fitness Predicts Daily Coping Better Than Physical Activity

JOURNAL OF APPLIED BIOBEHAVIORAL RESEARCH, Issue 1 2000
Thomas G. Plante
One hundred sixty-six participants (70 males, 96 females) completed a series of questionnaires measuring perceived fitness, social desirability, self-esteem, hope, and perceived stress levels and coping abilities. Participants were then given an activity monitoring device to wear for 1 week. Participants recorded daily measures of physical activity, perceived fitness, and perceived stress and coping over 7 days. Results revealed that although perceived physical fitness was reliably associated with coping, actual physical activity was not. These associations remained even after statistically controlling for gender, social desirability, self-esteem, hope, perceived stress, and anxiety. Findings suggest that perceived physical fitness may be a better predictor of daily coping than actual physical activity. [source]

Fitness, fatness and activity as predictors of bone mineral density in older persons

JOURNAL OF INTERNAL MEDICINE, Issue 5 2002
K. J. Stewart
Abstract. Stewart KJ, DeRegis JR, Turner KL, Bacher AC, Sung J, Hees PS, Tayback M, Ouyang P (Johns Hopkins Bayview Medical Center, Johns Hopkins University, School of Medicine, Baltimore, MD, USA). Fitness, fatness, and activity as predictors of bone mineral density in older persons. J Intern Med 2002; 252: 381,388. Objectives. To determine relationships of bone mineral density (BMD) with fitness, physical activity, and body composition and fat distribution. Design. Cross-sectional. Setting. General Clinical Research Center, Johns Hopkins Bayview Medical Center, Baltimore, Maryland. Subjects. Men (n = 38) and women (n = 46), aged 55,75 years with high normal blood pressure or mild hypertension but otherwise healthy. Methods. Aerobic fitness (oxygen uptake) on a treadmill, muscle strength by one-repetition maximum, activity by questionnaire, abdominal obesity by magnetic resonance imaging; anthropometrics, and body composition by dual energy X-ray absorptiometry (DXA) which measured total fat and lean mass, and BMD for the total skeleton, lumbar spine (L1,L4) and total hip. Results. Aerobic fitness did not correlate with BMD. Using multivariate analysis to ascertain independent contributions to the variance in BMD, in women, with adjustment for hormone replacement therapy (HRT), total skeleton BMD was independently related to muscle strength and abdominal total fat; total hip BMD to body weight; lumbar spine BMD to abdominal total fat. HRT also influenced BMD in the lumbar spine. In men, lumbar spine BMD was independently related to abdominal total fat physical activity and total hip BMD related to lower body strength. P < 0.05 for all of these correlations. Conclusions. Abdominal obesity and muscle strength emerge as predominant correlates of BMD in older persons with stronger relationships seen in women. Body weight and HRT also explained portions of the variance in BMD in women. Whether abdominal obesity is simply a marker for general obesity or has independent protective effects on bone is yet to be determined. [source]

University of life or academia?

JOURNAL OF NURSING MANAGEMENT, Issue 6 2008
A review of community matrons/case managers continuing professional development; accessing a post-graduate programme without meeting the current academic entry criteria
Aims, To inform managers and gatekeepers of the pre-requisites for staff engaging in post-graduate level study. To acknowledge the support students in new roles require in clinical practice and continuing professional development (CPD). Background, A post - graduate course for case managers/community matrons was developed as a rapid response to government policy. As a result, candidates entered this programme with non-traditional requirements. However, this did not appear to hinder their success. Evaluation, Student entry data and their achievements on completion were collected and compared with another post-graduate course that did require standard entry academic requirements. Final results were analysed and a narrative obtained from students and mentors. Key issues, Gatekeepers should recognize the importance of past experience and motivation of candidates in relation to CPD and also the student's insight and self-awareness when accessing courses. Conclusion, Candidates accessing post-graduate courses can achieve learning outcomes at an advanced level when given the right support and are capable of undertaking the role of case manager/community matron . Implications for nursing management, The article is relevant in light of the current financial constraints for Trusts to ration the funding of CPD. Choosing the right person to attend the right course often depends on the manager's discretion and not necessarily the candidates' ability or motivation. It highlights the importance of not only recognizing the candidates' academic level but also their motivation to study, and with careful selection candidates should be allowed the opportunity to access higher levels of CPD. Fitness to practice is also an important aspect to consider on completion of a course and this can be achieved with the mapping of competencies in relation to the post holder's specific job. [source]

Fitness, daily activity and body composition in children with newly diagnosed, untreated asthma

ALLERGY, Issue 11 2009
S. Vahlkvist
Background:, Information about how the asthma disease affects the life style and health in children is sparse. Aim:, To measure fitness, daily physical activity and body composition in children with newly diagnosed, untreated asthma and healthy controls, and to assess the association between the level of asthma control and these parameters. Methods:, Daily physical activity measured using accelerometry, cardiovascular fitness and body composition (per cent fat, per cent lean tissue and bone mineral density) were measured in 57 children with newly diagnosed, untreated asthma and in 157 healthy age- and sex-matched controls. The level of asthma control was assessed by measurements of a variety of asthma outcomes. Results:, Children with asthma were less fit (35.1 vs 39.3 ml O2/min/kg) (P < 0.001), had a higher body per cent fat (22.8 vs 19.5%) (P < 0.01) and a higher frequency of overweight (24.6 vs 14.2%) (P < 0.05) than healthy controls. Per cent body fat correlated negativly to overall daily activity (P < 0.001) and to time spent in high or vigorous activity (P < 0.001). Fitness corrrelated positively to time spent in high and vigorous activity (P < 0.001). Within the asthma group, the level of asthma control, fitness and the time spent in vigorous activity correlated positively (P < 0.02). Conclusion:, Children with untreated asthma are less fit and have a higher body per cent fat and frequency of obesity than their healthy peers. Uncontrolled asthma is associated with a reduced fitness and daytime spent in intensive activity. Overweight children are physically less active than normal weight children. [source]

Fitness and genetic variation of Viola calaminaria, an endemic metallophyte: implications of population structure and history

PLANT BIOLOGY, Issue 6 2008
J.-P. Bizoux
Abstract We investigated variations in genetic diversity and plant fitness in a rare endemic metallophyte of calamine soils, Viola calaminaria, in relation to population size, population connectivity and population history in order to evaluate and discuss potential conservation strategies for the species. Mean population genetic diversity (Hs = 0.25) of V. calaminaria was similar to endemic non-metallophyte taxa. Twenty-one per cent of the genetic variation was partitioned among populations and a low (9%) but significant differentiation was found among geographical regions. Our results did not support the hypothesis that the acquisition of metal tolerance may result in reduced genetic diversity, and suggested that strict metallophytes do not exhibit higher inter-population differentiation resulting from scattered habitats. There were no relationships between population genetic diversity and population size. Significant correlations were found between plant fitness and (i) population size and (ii) connectivity index. Recently-founded populations exhibited the same level of genetic diversity as ancient populations and also possessed higher plant fitness. There was no indication of strong founder effects in recently-established populations. The results suggest that the creation of habitats through human activities could provide new opportunities for conservation of this species. [source]

Presidential Fitness and Presidential Lies: The Historical Record and a Proposal for Reform

PRESIDENTIAL STUDIES QUARTERLY, Issue 1 2010
ROBERT DALLEK
Since at least the late nineteenth century, U.S. presidents have engaged in substantial and unjustified deception in a variety of domains, and future presidents will continue to do so unless new mechanisms are created to ensure greater accountability and oversight. The problem is particularly apparent in two very different domains: personal health and foreign policy. Several presidents and presidential candidates have concealed grave health conditions that impaired their ability to govern. As future presidential candidates are unlikely to be more forthcoming about their health, the public interest should be protected by an independent medical panel to evaluate presidential candidates. In foreign policy, recent decades have seen several egregious cases of presidential deception, including Lyndon B. Johnson on Vietnam, Richard M. Nixon on the Chilean coup, and George W. Bush on weapons of mass destruction in Iraq. Such ethical lapses justify a constitutional recall amendment, under which a congressional supermajority could subject the continued service of a sitting president to a popular vote. [source]

Fitness: The Ultimate Marker for Risk Stratification and Health Outcomes?

PREVENTIVE CARDIOLOGY, Issue 1 2007
Barry A Franklin PhD
First page of article [source]

Moderate or Vigorous Intensity Exercise: Which Is Better for Improving Aerobic Fitness?

PREVENTIVE CARDIOLOGY, Issue 1 2005
David P. Swain PhD
First page of article [source]

New Insights on the Threshold Intensity for Improving Cardiorespiratory Fitness

PREVENTIVE CARDIOLOGY, Issue 3 2003
Barry A. Franklin PhD
First page of article [source]

Composition of alveolar surfactant changes with training in humans

RESPIROLOGY, Issue 3 2000
Ian R. Doyle
Objective: We test the hypothesis that the changes we observed previously in the relative amounts of disaturated phospholipids (DSP), cholesterol (CHOL), and surfactant protein-A (SP-A) in human alveolar surfactant in response to acute exercise, and which were related to fitness, can be induced by training. Methodology: We examine the effect of 7 weeks' training on these major surfactant components, together with surfactant protein-B (SP-B), in bronchoalveolar lavage fluid harvested from 17 males, both at rest and after acute exercise. Fitness was assessed as workload/heart rate achieved during cycling for 30 min at 90% of theoretical maximal heart rate, and was increased in all subjects following training (mean increase 22.2 ± 3.91%; P = 0.001). Results: Training significantly increased the SP-A/DSP, SP-B/DSP, SP-A/CHOL and SP-A/SP-B ratios in whole surfactant harvested from subjects both at rest and immediately following exercise. Training also increased the SP-B/CHOL ratio at rest. Changes were particularly marked at rest in the SP-A/DSP, SP-A/CHOL, and SP-B/CHOL ratios in the tubular myelin-rich fraction, and after exercise in the SP-A/DSP, SP-A/CHOL, and SP-A/SP-B ratios in the tubular myelin-poor fraction. Conclusion: We conclude that training markedly alters the composition of alveolar surfactant both at rest and with exercise; the physiological significance of these changes remains to be determined. [source]

GJB2 Mutations in Mongolia: Complex Alleles, Low Frequency, and Reduced Fitness of the Deaf

ANNALS OF HUMAN GENETICS, Issue 2 2010
Mustafa Tekin
SUMMARY We screened the GJB2 gene for mutations in 534 (108 multiplex and 426 simplex) probands with non-syndromic sensorineural deafness, who were ascertained through the only residential school for the deaf in Mongolia, and in 217 hearing controls. Twenty different alleles, including four novel changes, were identified. Biallelic GJB2 mutations were found in 4.5% of the deaf probands (8.3% in multiplex, 3.5% in simplex). The most common mutations were c.IVS1 + 1G > A (c.-3201G > A) and c.235delC with allele frequencies of 3.5% and 1.5%, respectively. The c.IVS1 + 1G > A mutation appears to have diverse origins based on associated multiple haplotypes. The p.V27I and p.E114G variants were frequently detected in both deaf probands and hearing controls. The p.E114G variant was always in cis with the p.V27I variant. Although in vitro experiments using Xenopus oocytes have suggested that p.[V27I;E114G] disturbs the gap junction function of Cx26, the equal distribution of this complex allele in both deaf probands and hearing controls makes it a less likely cause of profound congenital deafness. We found a lower frequency of assortative mating (37.5%) and decreased genetic fitness (62%) of the deaf in Mongolia as compared to the western populations, which provides an explanation for lower frequency of GJB2 deafness in Mongolia. [source]

Fitness Among Individuals with Early Childhood Deafness: Studies in Alumni Families from Gallaudet University

ANNALS OF HUMAN GENETICS, Issue 1 2010
Susan H. Blanton
Summary The genetic fitness of an individual is influenced by their phenotype, genotype and family and social structure of the population in which they live. It is likely that the fitness of deaf individuals was quite low in the Western European population during the Middle Ages. The establishment of residential schools for deaf individuals nearly 400 years ago resulted in relaxed genetic selection against deaf individuals which contributed to the improved fitness of deaf individuals in recent times. As part of a study of deaf probands from Gallaudet University, we collected pedigree data, including the mating type and the number and hearing status of the children of 686 deaf adults and 602 of their hearing siblings. Most of these individuals had an onset of severe to profound hearing loss by early childhood. Marital rates of deaf adults were similar to their hearing siblings (0.83 vs. 0.85). Among married individuals, the fertility of deaf individuals is lower than their hearing siblings (2.06 vs. 2.26, p = 0.005). The fitness of deaf individuals was reduced (p = 0.002). Analysis of fertility rates after stratification by mating type reveals that matings between two deaf individuals produced more children (2.11) than matings of a deaf and hearing individual (1.85), suggesting that fertility among deaf individuals is influenced by multiple factors. [source]

Titelbild: Bautechnik 10/2007

BAUTECHNIK, Issue 10 2007
Article first published online: 1 OCT 200
In fußläufiger Entfernung zur Altstadt von Stuttgart-Bad Cannstatt ist mit dem Cannstatt Carré ein Einkaufs-, Erlebnis- und Geschäftszentrum mit ca. 22000 m2 Einzelhandels- und 13000 m2 Büroflächen, 2000 m2 für Fitness- und Wellnesseinrichtungen sowie 750 Pkw-Stellplätzen entstanden (Architekten: EPA Planungsgruppe GmbH). Ein großzügiges ovales Lichtdach mit integrierten RWA führt reichlich Tageslicht in die unterhalb gelegenen Verkehrs- und Handelszonen. Hierbei handelt es sich um eine Stahlkonstruktion mit Aluminium-Aufsatzelementen. (Foto: Schüco International KG) [source]

Fitness, developmental instability, and the ontogeny of fluctuating asymmetry in Daphnia magna

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2006
LEIF CHRISTIAN STIGE
Fluctuating asymmetry (FA) is the most commonly used measure of developmental instability. The relation between FA and individual fitness remains controversial, partly due to limited knowledge on the mechanisms behind variation in FA. To address this, we investigated the associations between FA, growth and reproduction as well as the ontogeny of FA in a clonal population of Daphnia magna. FA was not correlated with growth and reproduction, either at the between- or the within-individual level, in a high (N = 48 individuals) or in a low (N = 52 individuals) food-quantity regime. There were therefore no indications of functional effects of FA or of phenotypic trade-offs between developmental stability, growth and reproduction. Individual asymmetries varied randomly in sign and magnitude between subsequent molts (N = 19 individuals, 9,11 instars), but the levels of FA were generally lowest at intermediate ages. No feedback between right and left sides was detected. This suggests that FA only reflects the most recent growth history, that developmental instability may increase in old age, and that FA depends on processes operating on each side of the body independently. The results also suggest that FA differences within and among individual Daphnia are largely random, with limited biological significance. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 88, 179,192. [source]