Gender differences for growth in North American Atlantic salmon.

An assumption in aquaculture of Atlantic salmon is that male and female growth within families is perfectly genetically correlated. That is, families would rank identically if based on male growth only or female growth only. Also, growth in freshwater and sea water is assumed to be highly correlated between males and females within families. However, structural analysis of the DNA of Atlantic salmon has found that the linkage maps of females differ significantly from that of males. Genetic variability for any trait measured on females could be greater or lesser than on males. Thus, male and female growth might be considered as separate traits giving rise to families ranking differently depending on gender. A multiple trait family model for weight and length at 3 years of age in Atlantic salmon according to gender was applied to data on North American Atlantic salmon obtained from the Oak Bay Hatchery in New Brunswick, Canada. Genetic correlations between male and female growth in both freshwater and sea water were estimated by Bayesian methods. The estimates support the possible existence of gender dimorphism in North American Atlantic salmon for growth traits.

Pragmatic intervention for increasing self-directed exercise behaviour and improving important health outcomes in people with multiple sclerosis: a randomised controlled trial.

BACKGROUND: Exercise programmes that can demonstrate evidence of long-lasting clinical effectiveness are needed for people with multiple sclerosis (PwMS). OBJECTIVE: The objective of this study was to assess the effects of a practically implemented exercise programme on self-directed exercise behaviour and important health outcomes in PwMS to nine months of follow-up. METHODS: We conducted a parallel-arm, randomised controlled trial: 120 PwMS (Expanded Disability Status Scale (EDSS) 1.0-6.5) randomised to a three-month exercise intervention plus usual care, or usual care only. Two supervised plus one home-exercise session (weeks 1-6) were followed by one supervised and two home-exercise sessions (weeks 7-12). Cognitive-behavioural techniques promoted long-term exercise behaviour change. Outcomes were blindly assessed at baseline and at three and nine months after randomisation. The primary outcome was self-reported exercise behaviour (Godin Leisure Time Exercise Questionnaire (GLTEQ)). Secondary outcomes included fatigue and health-related quality of life (HRQoL). RESULTS: The intervention increased self-reported exercise (9.6 points; 95% CI: 2.0 to 17.3 points; p = 0.01) and improved fatigue (p < 0.0001) and many HRQoL domains (p ≤ 0.03) at three months. The improvements in emotional well-being (p = 0.01), social function (p = 0.004) and overall quality of life (p = 0.001) were sustained for nine months. CONCLUSION: This pragmatic approach to implementing exercise increases self-reported exercise behaviour, improves fatigue and leads to a sustained enhancement of HRQoL domains in PwMS.

Cost effectiveness of a pragmatic exercise intervention (EXIMS) for people with multiple sclerosis: economic evaluation of a randomised controlled trial.

BACKGROUND: Exercise is a safe, non-pharmacological adjunctive treatment for people with multiple sclerosis but cost-effective approaches to implementing exercise within health care settings are needed. OBJECTIVE: The objective of this paper is to assess the cost effectiveness of a pragmatic exercise intervention in conjunction with usual care compared to usual care only in people with mild to moderate multiple sclerosis. METHODS: A cost-utility analysis of a pragmatic randomised controlled trial over nine months of follow-up was conducted. A total of 120 people with multiple sclerosis were randomised (1:1) to the intervention or usual care. Exercising participants received 18 supervised and 18 home exercise sessions over 12 weeks. The primary outcome for the cost utility analysis was the incremental cost per quality-adjusted life year (QALY) gained, calculated using utilities measured by the EQ-5D questionnaire. RESULTS: The incremental cost per QALY of the intervention was £10,137 per QALY gained compared to usual care. The probability of being cost effective at a £20,000 per QALY threshold was 0.75, rising to 0.78 at a £30,000 per QALY threshold. CONCLUSION: The pragmatic exercise intervention is highly likely to be cost effective at current established thresholds, and there is scope for it to be tailored to particular sub-groups of patients or services to reduce its cost impact.

Evolutionary history of the Afro-Madagascan Ixora species (Rubiaceae): species diversification and distribution of key morphological traits inferred from dated molecular phylogenetic trees.

BACKGROUND AND AIMS: Previous work on the pantropical genus Ixora has revealed an Afro-Madagascan clade, but as yet no study has focused in detail on the evolutionary history and morphological trends in this group. Here the evolutionary history of Afro-Madagascan Ixora spp. (a clade of approx. 80 taxa) is investigated and the phylogenetic trees compared with several key morphological traits in taxa occurring in Madagascar. METHODS: Phylogenetic relationships of Afro-Madagascan Ixora are assessed using sequence data from four plastid regions (petD, rps16, rpoB-trnC and trnL-trnF) and nuclear ribosomal external transcribed spacer (ETS) and internal transcribed spacer (ITS) regions. The phylogenetic distribution of key morphological characters is assessed. Bayesian inference (implemented in BEAST) is used to estimate the temporal origin of Ixora based on fossil evidence. KEY RESULTS: Two separate lineages of Madagascan taxa are recovered, one of which is nested in a group of East African taxa. Divergence in Ixora is estimated to have commenced during the mid Miocene, with extensive cladogenesis occurring in the Afro-Madagascan clade during the Pliocene onwards. CONCLUSIONS: Both lineages of Madagascan Ixora exhibit morphological innovations that are rare throughout the rest of the genus, including a trend towards pauciflorous inflorescences and a trend towards extreme corolla tube length, suggesting that the same ecological and selective pressures are acting upon taxa from both Madagascan lineages. Novel ecological opportunities resulting from climate-induced habitat fragmentation and corolla tube length diversification are likely to have facilitated species radiation on Madagascar.

Pragmatic exercise intervention for people with multiple sclerosis (ExIMS trial): study protocol for a randomised controlled trial.

Exercise is an effective intervention for improving function, mobility and health-related quality of life in people with multiple sclerosis (PwMS). Questions remain however, regarding the effectiveness of pragmatic exercise interventions for evoking tangible and sustained increases in physical activity and long-term impact on important health outcomes in PwMS. Furthermore, dose-response relationships between exercise and health outcomes have not previously been reported in PwMS. These issues, and improved knowledge of cost effectiveness, are likely to influence key decisions of health policy makers regarding the implementation of exercise therapy as part of the patient care pathway for PwMS. Hence, the primary aim of this study is to investigate whether a 12-week tapered programme of supervised exercise, incorporating cognitive-behavioural techniques to facilitate sustained behaviour change, is effective for evoking improvements in physical activity and key health outcomes in PwMS over 9 months of follow-up. A total of 120 PwMS will be randomised (1:1) to either a 12-week pragmatic exercise therapy intervention or usual care control group. Participants will be included on the basis of a clinical diagnosis of MS, with an expanded disability status score (EDSS) between 1 and 6.5. Outcome measures, to be assessed before and after the intervention and 6 months later, will include physical activity, clinical and functional measures and health-related quality of life. In addition, the cost effectiveness of the intervention will be evaluated and dose-response relationships between physical activity and the primary/secondary outcomes in those with mild and more severe disease will be explored.

Genetic, maternal, and environmental variance components for body weight and length of Atlantic cod at 2 points in life.

Variance components were estimated for 2 body size traits of Atlantic cod at 2 time points. Wild-caught founders from 3 regions off eastern North America were spawned and their progeny were reared at 2 locations in 2 consecutive years. Full-sib families (n = 148) were kept separate until individuals achieved a size large enough to be tagged. At that time (220 d of age), BW and length of 47,637 offspring from 90 sires and 89 dams were recorded. The juveniles were then transferred to sea cages at 3 sites, where they grew further for more than a year. A second set of measurements was collected on 11,839 fish (634 d of age). Dispersion parameters were estimated using REML in bivariate analyses. Models included fixed degree-days (covariate), year × location subclasses, and genetic groups composed of connected families within region of origin. Random factors were animal (additive genetic effects), considering known relationships among the fish; dam (maternal effects); and family (effects common to full-sibs). At tagging, heritability estimates were small to moderate (0.15 and 0.24 for BW and length, respectively; SE = 0.14), similar to or somewhat larger than the proportions of variation ascribed to dams and families (11 to 16%). Later, heritability estimates were greater (0.27 ± 0.08 and 0.31 ± 0.09 for BW and length, respectively), whereas dam and family variance proportions were very small (3 to 4%). Omitting maternal or family components substantially increased the values obtained for heritability at both time points. At the later point, failure to account for maternal effects inflated heritability estimates by about 24% for both traits; ignoring family effects had double the impact. These effects persisted even though endogenous feeding lasts only a couple of weeks in this species and the fish had been pooled since tagging. Discarding data from parents that were completely confounded with their mates decreased heritability estimates slightly (by 0.04, for both traits) at the second point, with no loss of precision despite 15% fewer records and 34% fewer parents; the improved design seemed to have more fully disentangled the additive genetic effects. Estimates of genetic correlations between traits and between time points were very large (>0.89). The results imply that genetic variation exists for body size of cod at both stages. Poor data structure and inadequate models can potentially lead to overstatement of heritability, and thus also of the predicted selection response.

Breed effects on growth performance, carcass characteristics, fatty acid composition, and palatability attributes in finishing steers.

Crossbred steers (n = 136) were used to assess breed differences in growth performance, carcass characteristics, fatty acid composition (total lipids and phospholipids), and palatability attributes of longissimus muscle. A multiple regression model was applied to crossbreeding data to estimate genetic differences between Simmental and Red Angus at the same level of backfat finish (10 mm). Simmental spent 71 more (P < 0.001) days on feed to acquire the same degree of backfat thickness as Red Angus, had heavier (P < 0.001) slaughter weights, larger (P = 0.002) longissimus muscle area, and increased (P = 0.023) lean yield. Average daily gain did not differ (P = 0.297) between breeds. Simmental were less (P = 0.012) efficient in converting feed to gain than Red Angus. Generally, there were few breed differences in palatability attributes for longissimus and semitendinosus muscles, with the exception of increased (P < 0.05) beef flavor scores for Simmental beef vs Red Angus beef across both muscles. For total lipids, concentrations of myristoleic acid (14:1), palmitoleic acid (16:1), and vaccenic acid (18:1n-7), along with n-6 to n-3 fatty acid (n-6:n-3) ratio, were greater (P < 0.05) in Simmental than Red Angus. In contrast, concentrations of margaric acid (17:0), eicosapentaenoic acid (20:5n-3), and total n-3 polyunsaturated fatty acids (n-3 PUFA) were greater (P < 0.05) in Red Angus than Simmental. For phospholipids, Simmental had lower (P < 0.05) amounts of 20:5n-3, docosahexaenoic acid (22:6n-3), and n-3 PUFA, with a greater (P = 0.017) n-6:n-3 ratio. Activity of delta9-desaturase enzyme in the conversion of palmitic acid (16:0) to 16:1 was greater (P = 0.001) in total lipids from Simmental as compared with Red Angus. A genetic basis for fatty acid differences is suggested, although the biological and practical significance needs to be demonstrated.

Influence of management system on litter size, lamb growth, and carcass characteristics in sheep.

Three management systems (winter, spring, and late summer) distinguished by season of lambing and management practices were compared for litter size born and weaned and growth and carcass characteristics of lambs. Three sire breeds (Cheviot, Rambouillet, and Suffolk) and three dam breeds (Florida Native, Native-X, and Synthetic-X) were used in 698 matings over a 3-yr period. System affected (P < .01) litter size born. Spring lambing yielded more lambs (1.62) than winter (1.49) and late summer (1.12). The winter-born lambs were lighter but fatter (P < .05), and spring-born lambs were leaner with higher leg conformation and carcass quality scores. The late summer-born lambs were not different from spring-born lambs. Wethers had higher (P < .01) weights off test than ewe lambs (43.9 vs 42 kg) but had lower (P < .01) leg conformation scores, percentage kidney and pelvic fat, yield grade, and dressing percentages. Dam breed effects were significant (P < .05) for average preweaning daily gains with 249+/-5, 201+/-9, and 191+/-9 g for progeny of Native-X, Florida Native, and Synthetic-X, respectively. Single-born lambs had higher daily gains (P < .05) than twins in a preweaning period in all management systems and higher postweaning and lifetime daily gains for winter and spring management systems.

Effects of data structure on variance of prediction error and accuracy of genetic evaluation.

Several features of data structure were studied to determine their effects on variance of prediction error and accuracy of evaluation. Assigning 50 sires with progeny to a portion of 10, 25, or 50 contemporary groups according to a sire model with and without additive genetic relationships, or assigning 50 individuals with their own record to one of 2, 5, or 10 contemporary groups according to an animal model, established the designs. Additive genetic relationships were based on stimulated pedigree files. Low, medium, and high heritabilities (.10, .25, and .40, respectively) were considered. The inverse of coefficient matrices gave variances of prediction error. Populations derived from the sire model (n = 8,100) consisted solely of progeny-tested individuals. For them, number of progeny had a quadratic (P < .001) association with variance of prediction error (R2 = 56 to 82%), which selection index theory underestimated when there were < 100 progeny. Number of direct connections (sires of contemporaries of progeny) together with progeny numbers explained variance of prediction error (R2 = 76 to 90%) better than either variable alone. With no direct connections, variance of prediction error was maximum unless a relative with at least one direct connection itself existed. Populations derived from the animal model (n = 900) consisted of animals with designs representing a progeny test, performance test, or a combination of both (34, 41, and 25% of the total, respectively). For performance-tested animals (without progeny), number of genetic connections was not highly correlated with variance of prediction error (r = -.10, across h2), but relatives prevented zero accuracies when contemporary groups consisted of one animal. Even when animals had no relatives, more than five members per contemporary group gave little additional increase in accuracy. For other than a progeny test, designs were complex, being described by many variables that were confounded.

Estimation of variance components for lamb weights in three sheep populations.

Variance components were estimated for lamb weight at birth, 50 d, and 100 d of age. Data from the Canadian flock recording program for lambs born in 1977 to 1991 for Hampshires (n = 6,395) and Polled Dorsets (n = 29,204) and 1982 to 1991 for Romanovs (n = 3,432) were studied. Observed weights were pre-adjusted for the effects of age of dam, sex of lamb, birth-rearing type, month or quarter of year of birth, parity-lambing interval, and age of dam at first lambing, using estimates derived from a fixed effects model including contemporary groups plus these factors. Pre-adjusting for nuisance variables reduced the number of equations in the model for variance component estimation. A single-trait animal model with derivative-free restricted maximum-likelihood procedures was used. Random effects were additive direct and maternal genetic, litter (common environmental), and error. An alternate model excluded maternal genetic effects. Estimates of litter variance as a proportion of phenotypic variance were of moderate size (.12 to .43) and consistent across breeds and models. The mean correlation between direct and maternal genetic effects, across traits and breeds, weighted by the number of animals, was -.40 (SE = .15). The maternal genetic variance or direct-maternal genetic covariance component, or both, was different from zero (P < .05) for all traits in Hampshires and Polled Dorsets, suggesting that maternal effects were important for weight of lambs even at 100 d of age. Estimates of direct heritability ranged from .05 to .45, varying across traits, breeds, and models.(ABSTRACT TRUNCATED AT 250 WORDS)

Landfill site restoration: the inimical challenges of ethylene and methane.

Vertically migrating landfill gases pose inimical challenges to site revegetation strategies. Laboratory studies were made to examine the efficacy of ectomycorrhizae and soil cover to obviate the challenges of ethylene and methane. In the presence of ethylene concentrations