Efecto de dos estrategias de agrupación de padres fantasmas en la evaluación genética de rasgos de crecimiento en el ganado Braunvieh mexicano

The study aimed to compare two grouping strategies for unknown parents or phantom parent groups (PPG) on the genetic evaluation of growth traits for Mexican Braunvieh cattle. Phenotypic data included birth (BW), weaning (WW) and yearling (YW) weights. Pedigree included 57,341 animals. The first strategy involved 12 PPG (G12) based on the birth year of the unknown parent’s progeny and the sex of the unknown parent, while the second involved 24 PPG (G24) based on the birth year of the unknown parent’s progeny and 4-selection pathways. The animal models included fixed effects and the random direct additive genetic effect; WW also included random maternal genetic and maternal permanent environmental effects. Product-moment correlations between EBV from G0 (no PPG) and G12 were 0.96, 0.77 and 0.69 for BW, WW and YW, respectively, and between EBV from G0 and G24 were 0.91, 0.54, and 0.53, respectively. Corresponding rank correlations between G0 and G12 were 0.94, 0.77, and 0.72, and between G0 and G24 were 0.89, 0.61, and 0.60. Genetic trends showed a base deviation from the genetic trend of G0, except for BW of G12. The results did not support the use of the two grouping strategies on the studied population and traits, and further research is required. Introducing PPG to the model, enough phenotype contribution from descendants to PPG, and avoiding collinearity between PPG and fixed effects are important. Genetic groups should reflect changes in the genetic structure of the population to the unknown parents, including different sources of genetic materials, and changes made by selection over time.

Teachers’ Use of Within-Class Ability Groups in the Primary Classroom: A Mixed Methods Study of Social Comparison

It is common practice within primary classrooms for teachers to spilt children into different ability groups so that children of similar level are taught together. Whilst this practice is used across the globe, research is mixed on the benefits of such grouping strategy. This paper presents data collected from mixed methods research which investigated teachers use of grouping strategies and social comparison, the act of comparing oneself with others. It focuses on when, why and with whom children from different ability groups compare themselves and the impact this has on their self-perceptions. Drawing upon data from children aged between 10 and 11 years from 12 primary schools, social comparison was found to play a significant role in daily classroom life for some children. The study identified different strands of the social comparison process including acknowledgment, topic, target, and direction, and it revealed positive and negative effects of social comparison. A difference by ability group was identified. Children within the low ability group were particularly vulnerable to the negative effects of social comparison and found to engage in more frequent and intentional social comparisons which were heavily relied upon for self-evaluation and performance evaluation. The paper discusses the educational implications of social comparison regarding pupil ability grouping strategies, motivation, engagement, and academic performance. Implications for teacher education and professional development is discussed.

Receiver grouping strategies for hybrid Geometric-mean Reverse-time migration

Geometric-mean Reverse-time migration (GmRTM), a powerful cross-correlation-based imaging method, generates higher-resolution source images and is more robust to noise compared to conventional time-reversal imaging. The price to pay is the higher computational costs. Alternatively, we can adopt hybrid strategies by dividing the receivers into different groups. Conventional time reversal (i.e., wavefield summation) is performed inside each group, followed by the application of cross-correlation imaging condition among different groups. Such hybrid strategies can retain the advantages of both GmRTM and time-reversal, and are often more practical than pure GmRTM. Yet, designing appropriate grouping strategy is not trivial. Here, we propose two grouping strategies (adjacent and scattered) and use synthetic and field-data examples to evaluate their performance with various group numbers. In addition to the spatial resolution of the source image, robustness to random noise is another important assessment criterion, for which we consider two distribution patterns, such as concentrated and scattered, of traces contaminated with strong random noise. We also evaluated their effectiveness to visualize events (in the image domain) that are not completely recorded by all receivers. Our comprehensive tests illustrate the respective advantages of the two grouping strategies.

Effect of Nicotiana benthamiana exposed to long- or short-chain perfluoroalkyl substances: Levels, transfer and potential risk analysis

Background: Perfluoroalkyl substances (PFAS) can endanger human health through the food chain. However, the physiological mechanisms of crops exposed to PFAS are still unclear. Objectives: The physiology, phytotoxicity and accumulation of Solanaceae model crops Nicotiana benthamiana exposed to perfluorooctanoic acid (PFOA), hexafluoropropylene oxide-dimer acid (HFPO-DA) and their mixed contaminants have been studied. Results: (i) Biomass, relative electrical conductivity and catalase all decrease; (ii) Chlorophyll, peroxidase, hydrogen peroxide and malondialdehyde all increase; (iii) Superoxide dismutase and soluble sugar both increase and then decrease; (Ⅳ) The absorption and transport of K, Ca, Mg and Na are affected, particularly shoots; (V) PFOA has the highest toxicity and bioaccumulation. Conclusion: PFAS will damages the economic benefits of crops and people's health. So, its production and uses should be curtailed except for essential uses. Future direction: Substitute substances may be more harmful, so grouping strategies and evaluation framework should be established as soon as possible.

Differentiation and Grouping Practices as a Response to Heterogeneity – Teachers’ Implementation of Inclusive Teaching Approaches in Regular, Inclusive and Special Classrooms

Addressing students’ individual needs is a crucial component of inclusive teaching. However, empirical evidence comparing practices such as differentiation and grouping strategies within inclusive, regular and special classes is still lacking. The present study contrasts these settings using data from the German National Educational Panel Study (NEPS). Data from 1034 teachers (755 regular, 89 inclusive, 190 special teachers) teaching the subject German in secondary school (grade 5 to grade 8) were used. Results show the highest use of differentiation in special school classes. Teachers’ use the majority of grouping practices to a similar extent when comparing the three educational settings. Class size and the number of students with migration background were predictors for teachers’ use of differentiation, whereas patterns of grouping strategies were predicted by students’ gender and teachers’ experience.

Grouping strategies in numerosity perception between intrinsic and extrinsic grouping cues

The number of items in an array can be quickly and accurately estimated by dividing the array into subgroups, in a strategy termed “groupitizing.” For example, when memorizing a telephone number, it is better to do so by divide the number into several segments. Different forms of visual grouping can affect the precision of the enumeration of a large set of items. Previous studies have found that when groupitizing, enumeration precision is improved by grouping arrays using visual proximity and color similarity. Based on Gestalt theory, Palmer (Cognit Psychol 24:436, 1992) divided perceptual grouping into intrinsic (e.g., proximity, similarity) and extrinsic (e.g., connectedness, common region) principles. Studies have investigated groupitizing effects on intrinsic grouping. However, to the best of our knowledge, no study has explored groupitizing effects for extrinsic grouping cues. Therefore, this study explored whether extrinsic grouping cues differed from intrinsic grouping cues for groupitizing effects in numerosity perception. The results showed that both extrinsic and intrinsic grouping cues improved enumeration precision. However, extrinsic grouping was more accurate in terms of the sensory precision of the numerosity perception.

Optimization Inspired on Herd Immunity Applied to Non-Hierarchical Grouping of Objects

Characterized as one of the most important operations related to data analysis, one non-hierarchical grouping consists of, even without having any information about the elements to be classified, establish upon a finite collection of objects, the partitioning of the items that constitute it into subsets or groups without intersecting, so that the elements that are part of a certain group are more similar to each other than the items that belong to distinct group. In this context, this study proposes the application of a meta-heuristic inspired by herd immunity to the determination of the non-hierarchical grouping of objects, and compares the results obtained by this method with the answers provided by four other grouping strategies, described in the literature. In particular, the resulting arrangements of the classification of 33 benchmark collections, performed by the suggested algorithm, by the metaheuristic inspired by the particle swarm, by the genetic algorithm, by the K-means algorithm and by the meta-heuristic inspired by the thermal annealing process, were compared under the perspective of 10 different evaluation measures, indicating that the partitions established by the meta-heuristic inspired by the herd immunity may, in certain respects, be more favorable than the classifications obtained by the other clustering methods.