470,201 research outputs found

    Farm-level Economic Evaluation of Net Feed Efficiency in Australia’s Southern Beef Cattle Production System: A Multi-period Linear Programming Approach

    Get PDF
    Selection of beef cattle for increased net feed efficiency is a current major focus for research. At present the trait seems to be more apparent in Australia’s southern beef production system which is dominated by mixed farming enterprises. Farm-level evaluation of net feed efficiency should take account of the farming system for which it is proposed along with the dynamic nature of genetic selection. Gross margin, linear programming and multi-period linear programming approaches to evaluation of the trait at the farm-level using a representative farm are compared. Implications of the trait for researchers and beef producers are identifiedfarm-level evaluation, genetic traits, linear programming, Farm Management,

    On Flexible finite polygenic models for multiple-trait evaluation

    Get PDF
    Finite polygenic models (FPM) might be an alternative to the infinitesimal model (TIM) for the genetic evaluation of pedigreed multiple-generation populations for multiple quantitative traits. I present a general flexible Bayesian method that includes the number of genes in the FPM as an additional random variable. Markov-chain Monte Carlo techniques such as Gibbs sampling and the reversible jump sampler are used for implementation. Sampling of genotypes of all genes in the FPM is done via the use of segregation indicators. A broad range of FPM models, some combined with TIM, are empirically tested for the estimation of variance components and the number of genes in the FPM. Four simulation scenarios were studied, including genetic models with 5 or 50 additive independent diallelic genes affecting the traits, and random selection or selection on one of the traits was performed. The results in this study were based on ten replicates per simulation scenario. In the case of random selection, uniform priors on additive gene effects led to posterior mean estimates of genetic variance that were positively correlated with the number of genes fitted in the FPM. In the case of trait selection, assuming normal priors on gene effects also led to genetic variance estimates for the selected trait that were negatively correlated with the number of genes in the FPM. This negative correlation was not observed for the unselected trait. Treating the number of genes in the FPM as random revealed a positive correlation between prior and posterior mean estimates of this number, but the prior hardly affected the posterior estimates of genetic variance. Posterior inferences about the number of genes should be considered to be indicative where trait selection seems to improve the power of distinguishing between TIM and FPM. Based on the results of this study, I suggest not replacing TIM by the FPM, but combining TIM and FPM with the number of genes treated as random, to facilitate a highly flexible and thereby robust method for variance component estimation in pedigreed populations. Further study is required to explore the full potential of these models under different genetic model assumption

    The role of trait emotional intelligence and social and emotional skills in students’ emotional and behavioural strengths and difficulties : a study of Greek adolescents’ perceptions

    Get PDF
    The emergence of the Trait Emotional Intelligence construct shifted the interest in personality research to the investigation of the effect of global personality characteristics on behaviour. A second body of research in applied settings, the Social and Emotional Learning movement, emphasized the cultivation of emotional and social skills for positive relationships in a school environment. In this paper we investigate the role of both personality traits and social and emotional skills, in the occurrence of emotional and behavioural strengths and difficulties, according to adolescent students’ self-perceptions. Five hundred and fifty-nine students from state secondary schools in Greece, aged 12-14 years old, completed The Trait Emotional Intelligence Questionnaire-Adolescent Short Form, The Matson Evaluation of Social Skills with Youngsters, and The Strengths and Difficulties Questionnaire. It was found that students with higher Trait Emotional Intelligence and stronger social and emotional skills were less likely to present emotional, conduct, hyperactivity and peer difficulties and more likely to present prosocial behaviour. Gender was a significant factor for emotional difficulties and grade for peer difficulties. The paper describes the underlying mechanisms of students’ emotional and behavioural strengths and difficulties, and provides practical implications for educators to improve the quality of students’ lives in schools.peer-reviewe

    A note on the comparison of three near infrared reflectance spectroscopy calibration strategies for assessing herbage quality of ryegrass

    Get PDF
    peer-reviewedPerennial ryegrass (n = 1,836), Italian ryegrass (n = 137) and hybrid ryegrass (n = 103) herbage was taken from harvested plots from the Irish national variety evaluation scheme and analysed for in vitro dry matter digestibility, water soluble carbohydrate concentration, crude protein concentration and buffering capacity. Spectral data were obtained using near infrared reflectance spectroscopy and three calibration strategies (global, species-specific or local) were utilised to relate the reference values to the spectral data. The local strategy generally provided the poorest estimation of herbage composition, with global and species-specific calibration strategies producing similarly accurate estimates of each quality trait. The higher accuracy and easier maintenance of the global strategy make it the recommended calibration method for analysing quality of ryegrass.Department of Agriculture, Food and the Marine Research Stimulus Fund (07 526

    Genome-wide linkage scan for loci associated with epilepsy in Belgian shepherd dogs.

    Get PDF
    BackgroundIdiopathic epilepsy in the Belgian shepherd dog is known to have a substantial genetic component. The objective of this study was to identify genomic regions associated with the expression of generalized seizures in the Belgian Tervuren and Sheepdog.ResultsDNA from 366 dogs, of which 74 were classified as epileptic, representing two extended families were subjected to a genome-wide linkage scan using 410 microsatellite markers yielding informative coverage averaging 5.95 +/- 0.21 Mb. Though previous studies based on pedigree analyses proposed a major gene of influence, the present study demonstrated the trait to be highly polygenic. Studies of complex disorders in humans indicate that a liberal composite evaluation of genetic linkage is needed to identify underlying quantitative trait loci (QTLs). Four chromosomes yielded tentative linkage based upon LOD scores in excess of 1.0. Possible QTLs within these regions were supported also by analyses of multipoint linkage, allele frequency, TDT, and transmission of haplotype blocks.ConclusionsTaken together the data tentatively indicate six QTLs, three on CFA 2, and one on each of CFA 6, 12, and 37, that support fine mapping for mutations associated with epilepsy in the Belgian shepherd. The study also underscores the complexity of genomic linkage studies for polygenic disorders

    Evaluation of the Psychometric Properties of the Five Facet of Mindfulness Questionnaire.

    Get PDF
    ObjectiveThe Five Facet of Mindfulness Questionnaire (FFMQ) is widely used to assess mindfulness. The present study provides a psychometric evaluation of the FFMQ that includes item response theory (IRT) analyses and evaluation of item characteristic curves.MethodWe administered the FFMQ, the Beck Depression Inventory-II, the Ruminative Response Scale, and the Emotion Regulation Questionnaire to a heterogenous sample of 240 community-based adults. We estimated internal consistency reliability, item-scale correlations, categorical confirmatory factor analysis, and IRT graded response models for the FFMQ. We also estimated correlations among the FFMQ scales and correlations with the other measures included in the study.ResultsInternal consistency reliabilities for the five FFMQ scales were 0.82 or higher. A five-factor categorical model fit the data well. IRT-estimated item characteristic curves indicated that the five response options were monotonically ordered for most of the items. Product-moment correlations between simple-summated scoring and IRT scoring of the scales were 0.97 or higher.ConclusionsThe FFMQ accurately identifies varying levels of trait mindfulness. IRT-derived estimates will inform future adaptations to the FFMQ (e.g., briefer versions) and the development of future mindfulness instruments

    Mapping functional traits: comparing abundance and presence-absence estimates at large spatial scales

    Get PDF
    Efforts to quantify the composition of biological communities increasingly focus on functional traits. The composition of communities in terms of traits can be summarized in several ways. Ecologists are beginning to map the geographic distribution of trait-based metrics from various sources of data, but the maps have not been tested against independent data. Using data for birds of the Western Hemisphere, we test for the first time the most commonly used method for mapping community trait composition – overlaying range maps, which assumes that the local abundance of a given species is unrelated to the traits in question – and three new methods that as well as the range maps include varying degrees of information about interspecific and geographic variation in abundance. For each method, and for four traits (body mass, generation length, migratory behaviour, diet) we calculated community-weighted mean of trait values, functional richness and functional divergence. The maps based on species ranges and limited abundance data were compared with independent data on community species composition from the American Christmas Bird Count (CBC) scheme coupled with data on traits. The correspondence with observed community composition at the CBC sites was mostly positive (62/73 correlations) but varied widely depending on the metric of community composition and method used (R2: 5.6×10−7 to 0.82, with a median of 0.12). Importantly, the commonly-used range-overlap method resulted in the best fit (21/22 correlations positive; R2: 0.004 to 0.8, with a median of 0.33). Given the paucity of data on the local abundance of species, overlaying range maps appears to be the best available method for estimating patterns of community composition, but the poor fit for some metrics suggests that local abundance data are urgently needed to allow more accurate estimates of the composition of communities

    Servant Leadership and its Relationships with Core Self-Evaluation and Job Satisfaction

    Get PDF
    Servant leadership is a growing topic in the leadership literature. Our study considered servant leadership’s relationship to two outcomes, core self-evaluation and job satisfaction. The former is particularly noteworthy because if servant leadership predicts core self-evaluation this would confirm that servant leadership affects important changes in employees as people, a central tenet of servant leadership. In addition, if servant leadership predicts core self-evaluation, this could add to the question of whether core self-evaluation is a non-changeable personality trait or is potentially malleable. We conducted a field study of three firms and found that servant leadership predicts both core self-evaluation and job satisfaction, and that core self-evaluation also predicts job satisfaction. This study contributes to servant leadership, and in general to values-based leadership, by observing a predictive relationship to core self-evaluation, which potentially adds new information about the impact servant leadership can have on individuals. This study confirms the findings of previous authors who found that servant leadership predicts job satisfaction
    corecore