Muon accelerators

We introduce a new phylogenetic reconstruction algorithm which, unlike most previous rigorous inference techniques, does not rely on assumptions regarding the branch lengths or the depth of the tree. The algorithm returns a forest which is guaranteed to contain all edges that are: 1) sufficiently long and 2) sufficiently close to the leaves. How much of the true tree is recovered depends on the sequence length provided. The algorithm is distance-based and runs in polynomial time

Estudo das associações genéticas entre perímetro escrotal e características reprodutivas de fêmeas Nelore Genetic association among scrotal circumference and female reproductive traits in Nellore

Os objetivos deste trabalho foram estimar parâmetros genéticos para as características perímetro escrotal (PE), medido aos 12 (PE12, n = 652) e 18 (PE18, n = 607) meses de idade, idade ao primeiro parto (IPP, n = 1582), datas do primeiro (DPP, n = 1582) e segundo partos (DSP, n = 644) e primeiro intervalo de partos (PIP, n = 644) de animais da raça Nelore. Os parâmetros foram estimados pelo método da máxima verossimilhança restrita, usando-se um modelo animal e incorporando 15.648 informações de pedigree. As estimativas de herdabilidade das análises incluindo somente uma variável foram 0,24±0,10; 0,31±0,10; 0,01±0,03; 0,11±0,05; 0,07±0,08; e 0,10±0,10, respectivamente, para PE12, PE18, IPP, DPP, DSP e PIP. Estas estimativas foram semelhantes às obtidas nas análises em que foram incluídas duas variáveis, com exceção da análise incluindo os dois PE (0,68 e 0,61 para PE12 e PE18, respectivamente). As estimativas de correlações genéticas entre PE12 e IPP, DPP, DSP e PIP foram, respectivamente, -1,00; -0,08; -0,71; e -0,37. Por outro lado, as correlações genéticas entre PE18 e as características observadas nas fêmeas foram, na mesma ordem, -1,00; 0,21; -0,35; e -0,44. A seleção para o PE12 seria mais efetiva que a seleção para o PE18, quando se deseja obter melhorias relacionadas às características reprodutivas das fêmeas.<br>The objectives of this work were to estimate of genetic parameters for scrotal circumference (SC) at 12 (SC12, n = 652) and 18 (SC18, n = 607) months of age, age at first calving (AFC, n = 1,582), first (FCD, n = 1,582) and second (SCD, n = 644) calving dates and first calving interval (FCI, n = 644) in Nellore cattle. Parameters were estimated using REML methodology, with animal models and considering the relations among 15,648 animals. Heritability estimates from univariate analyses were .24±.10, .31±.10, .01±.03, .11±.05, .07±.08 and .10±.10, respectively, for SC12, SC18, AFC, FCD, SCD and FCI. These values were close to the estimates from bivariate analyses, except for the analysis including both SC (heritability estimates of .61 and .68, respectively, for SC12 and SC18). Genetic correlation estimates between SC12 and, respectively, AFC, FCD, SCD and FCI were --1.00, -.08, -.71, and -.37. In the same order, genetic correlation between SC18 and female reproductive traits were --1.00, .21, -.35 and -.44. The selection for SC12 would be more effective than selection for SC18 when trying to improve the reproductive traits of the females

Analysis of ill-structured problem solving, mentoring functions, and perceptions of practicum teachers and mentors toward online mentoring in a field-based practicum

This article describes an exploratory study of question prompts and online mentoring (specifically a lateral or peer mentoring experience) in a field-based practicum that focused on teaching ill-structured problem solving of classroom discipline. Data were gathered on 26 in-service practicum teachers through online observations, online journal reports, questionnaires, and reflection logs. Results showed that the practicum teachers were successful in using the approach to plan and implement effective interventions for their students and that they perceived the online mentoring approach as being very beneficial in supporting their learning. A more detail analysis of seven practicum teachers and their mentors indicated that their mentors engaged in eight types of online mentoring functions; the most frequently used were asking practicum teachers to elaborate, and valuing the practicum teachers' contributions. The influence of the mentoring functions on the seven practicum teachers' ill-structured problem solving is also discussed. The study offers evidence that asynchronous online mentoring and question prompts can enhance the professional development of both practicum teachers and mentors by helping them learn about and apply intervention strategies in solving real-world teaching problems. © Springer Science+Business Media, Inc. 2007.link_to_subscribed_fulltex