Observation of Replica Symmetry Breaking in the 1D Anderson Localization Regime in an Erbium-Doped Random Fiber Laser

The analogue of the paramagnetic to spin-glass phase transition in disordered magnetic systems, leading to the phenomenon of replica symmetry breaking, has been recently demonstrated in a two-dimensional random laser consisting of an organic-based amorphous solid-state thin film. We report here the first demonstration of replica symmetry breaking in a one-dimensional photonic system consisting of an erbium-doped random fiber laser operating in the continuous-wave regime based on a unique random fiber grating system, which plays the role of the random scatterers and operates in the Anderson localization regime. The clear transition from a photonic paramagnetic to a photonic spin glass phase, characterized by the probability distribution function of the Parisi overlap, was verified and characterized. In this unique system, the radiation field interacts only with the gain medium, and the fiber grating, which provides the disordered feedback mechanism, does not interfere with the pump

Ordered Covering Arrays and Upper Bounds on Covering Codes in NRT spaces

This work shows several direct and recursive constructions of ordered covering arrays using projection, fusion, column augmentation, derivation, concatenation and cartesian product. Upper bounds on covering codes in NRT spaces are also obtained by improving a general upper bound. We explore the connection between ordered covering arrays and covering codes in NRT spaces, which generalize similar results for the Hamming metric. Combining the new upper bounds for covering codes in NRT spaces and ordered covering arrays, we improve upper bounds on covering codes in NRT spaces for larger alphabets. We give tables comparing the new upper bounds for covering codes to existing ones.Comment: 27 page

“If You Let Them, They Will Be on It 24 Hours a Day”: Qualitative Study Conducted in the United States Exploring Brazilian Immigrant Mothers’ Beliefs, Attitudes, and Practices Related to Screen Time Behaviors of Their Preschool-Age Children

Background: The increasing prevalence of excessive screen time (ST) among children is a growing public health concern, with evidence linking it to an increased risk of overweight and obesity among children. Objective: This study aimed to explore the beliefs, attitudes, and practices of Brazilian immigrant mothers living in the United States related to their preschool-age children’s ST behaviors. Methods: A qualitative study comprising 7 focus group discussions (FGDs) was conducted with Brazilian immigrant mothers living in the United States. All FGDs were audio-recorded and professionally transcribed verbatim. The Portuguese transcripts were analyzed using thematic analysis. Results: In total, 37 women participated in the FGDs. Analyses revealed that although most mothers expressed concerns for their preschool-age children’s ST, nearly all viewed ST as an acceptable part of their children’s daily lives. Furthermore, mothers perceived that ST has more benefits than disadvantages. The mothers’ positive beliefs about (eg, educational purposes and entertainment) and perceived functional benefits of ST (eg, ability to keep children occupied so tasks can be completed and facilitation of communication with family outside the United States) contributed to their acceptance of ST for their preschool-age children. Nevertheless, most mothers spoke of needing to balance their preschool-age children’s ST with other activities. Mothers reported using several parenting practices including monitoring time and content, setting limits and having rules, and prompting their children to participate in other activities to manage their preschool-age children’s ST. Conclusions: This study provides new information on the beliefs, attitudes, and practices of Brazilian immigrant mothers living in the United States related to their preschool-age children’s ST. Study findings revealed several potentially modifiable maternal beliefs and parenting practices that may provide important targets for parenting- and family-based interventions aimed at limiting preschool-age children’s ST

Culex quinquefasciatus vitellogenesis: morphological and biochemical aspects

The vitellogenic process in Culex quinquefasciatus, which is triggered by a blood meal, involves the synthesis, distribution and storage of the nutrients necessary for embryo development. The fat body of an adult female Cx. quinquefasciatus revealed two cell types: large trophocytes and small, eosinophilic, "oenocyte-like" cells, which show no morphological changes throughout the gonotrophic cycle. Trophocytes, which only begin to synthesise vitellogenin (Vg) 12 h post-blood meal (PBM), undergo a series of morphological changes following engorgement. These changes include the expansion of the rough endoplasmic reticulum (RER) and Golgi complex, which are later destroyed by autophagosomes. At 84 h PBM, trophocytes return to their pre-engorgement morphology. The ovarian follicles of non-blood-fed Cx. quinquefasciatus contain a cluster of eight undifferentiated cells surrounded by follicular epithelium. After engorgement, the oocyte membrane facing the perioocytic space increases its absorptive surface by microvilli development; large amounts of Vg and lipids are stored between 24 and 48 h PBM. Along with yolk storage in the oocyte, follicular cells exhibit the development of RER cisternae and electron-dense granules begin to fill the perioocytic space, possibly giving rise to endochorion. Later in the gonotrophic cycle, electron-dense vesicles, which are possible exochorion precursors, fuse at the apical membrane of follicular cells. This fusion is followed by follicular cell degeneration.FAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

GENERACIÓN DE HAZ CON MOMENTO ANGULAR ORBITAL REGISTRADO EN CRISTAL FOTORREFRACTIVO

En este trabajo se presenta una técnica novedosa para la generación de haces de luz con momento angular orbital (MAO), utilizando un cristal fotorrefractivo Bi12TiO20 (BTO) en un arreglo experimental donde un haz con MAO y un haz de referencia generan un registro holográfico interferométrico del haz. Una de las posibles aplicaciones, si se consigue fijar el holograma, podría ser el estudio de fenómenos de óptica y óptica no lineal utilizando haces con altas potencias

Parenting practices that may encourage and discourage physical activity in preschool-age children of Brazilian immigrant families: A qualitative study

Brazilians are a rapidly increasing Latino immigrant group in the United States (US), yet little research has examined factors influencing physical activity (PA) levels and behaviors of children growing up in Brazilian immigrant families. This information is needed to develop culturally sensitive interventions tailored to this population. Therefore, this qualitative study explored PA parenting practices used by Brazilian immigrant mothers living in the US. Thirty-seven Brazilian immigrant mothers with at least one child between the ages of 2 and 5 years participated in 1of 7 focus group discussions. Thematic analysis identified seven parenting practices that mothers employ that may encourage or facilitate physical activity their preschool-aged children’s PA including: 1) modeling PA; 2) engaging and being physically active with child; 3) providing logistic support; 4) encouraging, praising, and offering motivational support; 5) watching, supervising, and teaching children how to engage in PA; 6) monitoring and setting limits to child’s screen time; and 7) prompting child to be physically active. In addition, analysis identified four parenting practices that may discourage or inhibit children’s PA including: 1) modeling of sedentary behaviors; 2) having rules and restrictions due to safety- and weather-related concerns; 3) limiting child’s outdoor time due to parental time constraints; and 4) restricting child’s outdoor and play time as punishment. Furthermore, analyses demonstrated that social contextual factors (e.g., income, housing, neighborhood safety, etc.) influence mothers’ PA parenting practices and consequently, their children’s PA. This is the first qualitative study, to our knowledge, to explore PA parenting practices of Brazilian-born immigrant mothers living in the US. Future research should further explore PA parenting practices of Brazilian immigrant parents including quantifying PA parenting practices that encourage and discourage PA, as well as examining the influence of fathers’ PA parenting practices on young children’s PA

Semicircular canal size constrains vestibular function in miniaturized frogs

Miniaturization has evolved repeatedly in frogs in the moist leaf litter environments of rainforests worldwide. Miniaturized frogs are among the world’s smallest vertebrates and exhibit an array of enigmatic features. One area where miniaturization has predictable consequences is the vestibular system, which acts as a gyroscope, providing sensory information about movement and orientation. We investigated the vestibular system of pumpkin toadlets, Brachycephalus (Anura: Brachycephalidae), a clade of miniaturized frogs from Brazil. The semicircular canals of miniaturized frogs are the smallest recorded for adult vertebrates, resulting in low sensitivity to angular acceleration due to insufficient displacement of endolymph. This translates into a lack of postural control during jumping in Brachycephalus and represents a physical constraint resulting from Poiseuille’s law, which governs movement of fluids within tubes