Classroom composition and quality in early childhood education: a systematic review

High-quality early childhood education appears to be particularly beneficial for disadvantaged children, since it may help reduce an initial achievement gap. Yet, these children are frequently enrolled in disadvantaged classrooms with lower quality levels. Thus, classroom composition and quality may be associated, but evidence is scarce. In this review, we gathered evidence regarding classroom composition indexes and their association with observed classroom quality, reported in 25 studies that met the inclusion criteria. The majority of studies were conducted in the United States, with disadvantaged samples of children. Classroom composition indexes used were mainly calculations of the percentage, proportion, and average/mean of a particular type of characteristic at the classroom level, that generally captured classroom homogeneity. Most studies focused on minority and socioeconomic status. ECERS and CLASS were the most frequently used standardized observation measures of classroom quality. Evidence suggests that in classrooms with a high concentration of children with social minority status and from low income families, quality tends to be lower, particularly on the CLASS emotional and instructional support domains. Additional research, particularly outside the USA, focused primarily on the association between different types of classroom composition and ECE quality is warranted.info:eu-repo/semantics/acceptedVersio

Semiclassical Tunneling of Wavepackets with Real Trajectories

Semiclassical approximations for tunneling processes usually involve complex trajectories or complex times. In this paper we use a previously derived approximation involving only real trajectories propagating in real time to describe the scattering of a Gaussian wavepacket by a finite square potential barrier. We show that the approximation describes both tunneling and interferences very accurately in the limit of small Plank's constant. We use these results to estimate the tunneling time of the wavepacket and find that, for high energies, the barrier slows down the wavepacket but that it speeds it up at energies comparable to the barrier height.Comment: 23 pages, 7 figures Revised text and figure

A New Form of Path Integral for the Coherent States Representation and its Semiclassical Limit

The overcompleteness of the coherent states basis leads to a multiplicity of representations of Feynman's path integral. These different representations, although equivalent quantum mechanically, lead to different semiclassical limits. Two such semiclassical formulas were derived in \cite{Bar01} for the two corresponding path integral forms suggested by Klauder and Skagerstan in \cite{Klau85}. Each of these formulas involve trajectories governed by a different classical representation of the Hamiltonian operator: the P representation in one case and the Q representation in other. In this paper we construct a third representation of the path integral whose semiclassical limit involves directly the Weyl representation of the Hamiltonian operator, i.e., the classical Hamiltonian itself.Comment: 16 pages, no figure

Classroom quality and children's social skills and problem behaviors: dosage and disability status as moderators

Multiple studies have reported associations between early childhood education (ECE) quality and dosage and children’s social and behavior development, with some suggesting that this association may be stronger for specific groups of children. In this study, we examined the association between classroom quality and children’s social skills and problem behaviors, as reported by ECE teachers, as well as the moderating effects of ECE dosage and children’s disability status. Participants were 222 children (Mage = 63.75, SD = 7.77), including 180 typically developing (90 boys) and 42 children with disabilities (29 boys), from 44 inclusive classrooms in the Metropolitan Area of Lisbon, Portugal. Our results indicated that children’s social skills and behavior problems were not directly associated with observed classroom quality domains. However, lower classroom organization predicted lower social skills and higher externalizing behavior at higher number of months with the lead teacher; and instructional support predicted increased social skills for children with disabilities. Days absent from school predicted lower social skills. Overall, our results suggest that diverse types of dosage influence teacher’s reports of social and behavioral outcomes in different ways.info:eu-repo/semantics/acceptedVersio

Preschool teachers’ ideas about practices to promote peer relations: Using Q methodology to determine viewpoints

An internationally accepted definition of early childhood inclusion includes the right to achieve a sense of belonging and membership, positive social relationships, and friendships. Although Portuguese preschool curriculum guidelines value childchild interactions as an outcome by itself and as means to achieving other development and learning outcomes it does not explicitly mention social participation indicators. Additionally, information is lacking on Portuguese preschool teachers’ beliefs, priorities, and practices specifically related to the support of peer relations. This study was developed in the scope of the project Enhancing peer relationships: Preschool teachers' ideas and practices. One of its goals is to understand Portuguese preschool teacher’s ideas about what is important in supporting peer interactions, relationships, and group membership, for children with and without disabilities. To pursue this goal Q methodology was applied. We developed a Q sample consisting of 74 items that reflect a range of possible interventions targeted at enhancing social inclusion and peer interactions and relationships. The P sample was composed by 43 preschool teachers and their individual Q sorts were subjected to principal components analyses (PCA) followed by varimax rotation. A seven-component solution, explaining 55.5% of the variance, was considered the starting point for the decision-making process on the number of components to be considered as the best solution. Both statistical and conceptual criteria are being used to determine the final number of viewpoints. This presentation describes this decision-making process and the results will be discussed according to their implications for the global project.info:eu-repo/semantics/publishedVersio

Rutherford scattering with radiation damping

We study the effect of radiation damping on the classical scattering of charged particles. Using a perturbation method based on the Runge-Lenz vector, we calculate radiative corrections to the Rutherford cross section, and the corresponding energy and angular momentum losses.Comment: Latex, 11 pages, 4 eps figure

Dos nuevas especies del género Typhlocharis Dieck, 1869 de Portugal y notas sobre especies relacionadas (Coleoptera, Carabidae)

The present study describes two endogean carabid species of Typhlocharis Dieck, Typhlocharis rochapitei n. sp. and Typhlocharis crespoi n. sp., belonging to the T. diecki species group and to the T. outereloi species group, respectively. The work provides diagnostic characters and in particular, the structure of male genitalia. Affinities to putative relatives and keys for the identification of the diecki (all species) and outereloi (Portugal) species groups are also given.Se describen dos nuevas especies de carábidos Anillini endogeos (Coleoptera: Carabidae) de Portugal, Typhlocharis rochapitei n. sp. y Typhlocharis crespoi n. sp., pertencientes a los grupos diecki y outereloi, respectivamente. Se destacan los caracteres que las definen y, en particular, la estructura de la genitalia masculina. Se discute la afinidad con las especies más relacionadas y además se aportan datos ecológicos. Por último, se incluyen claves de todas las especies conocidas del grupo diecki y de las especies del grupo outereloi conocidas en Portugal