Aproximative solutions to the neutrino oscillation problem in matter

We present approximative solutions to the neutrino evolution equation calculated by different methods. In a two neutrino framework, using the physical parameters which gives the main effects to neutrino oscillations from nu{e} to another flavors for L=3000Km and E=1GeV, the results for the transition probability calculated by using series solutions, by to take the neutrino evolution operator as a product of ordered partial operators and by numerical methods, for a linearly and sinusoidally varying matter density are compared. The extension to an arbitrary density profile is discussed and the evolution operator as a product of partial operators in the three neutrino case is obtained.Comment: 12 pages, 5 figure

Species diversity of the deep-water gulper sharks (Squaliformes: Centrophoridae: Centrophorus) in North Atlantic waters - current status and taxonomic issues

The gulper sharks (genus Centrophorus) are a group of deep-water benthopelagic sharks with a worldwide distribution. The alpha taxonomy of the group has historically been problematic and the number of species included in the genus has varied considerably over the years and is still under debate. Gulper sharks are routinely caught in mid- and deep-water fisheries worldwide and some have shown a considerable decline in abundance in the last few decades. Clear and consistent species discrimination of Centrophorus is essential for an efficient and sustainable management of these fisheries resources. Our study used molecular cytochrome oxidase subunit I (COI) and 16S ribosomal RNA gene sequences and morphometric data to re-evaluate the diversity of Centrophorus in North Atlantic waters, including the Gulf of Mexico, the Caribbean, and the Mediterranean Seas. Molecular data separated North Atlantic Centrophorus into five well-supported groups whereas morphometric data separated these same five groups and suggested three additional groups for which no molecular data were available. Four of the five groups identified in the North Atlantic also occur in the Indian and/or Pacific Oceans, thus extending the reported range of some species considerably. A species identification key for North Atlantic Centrophorus is provided based on our findings. (c) 2014 The Linnean Society of Londo

Frequency of Multiple Paternity in the Spiny Dogfish Squalus acanthias in the Western North Atlantic

Multiple paternity (MP) has been shown to be widespread in elasmobranch fishes although its prevalence and the number of sires per litter vary considerably among species. In the squaloid shark Squalus acanthias, MP has been reported, but whether it is a common feature of the species\u27 reproductive strategy is unknown. In this study, we determined the frequency of MP in 29 litters of S. acanthias sampled from the lower Chesapeake Bay and coastal Virginia waters, using 7 highly polymorphic nuclear DNA microsatellite loci. Only 5 litters (17% of the total) were genetically polyandrous, with at least 2 sires per litter. Litter size increased with female size but was similar between polyandrous and monandrous females

Relations between theory of mind and academic school readiness: the moderating role of child gender

This study investigated the prospective relationship between preschoolers’ theory of mind (ToM) skills and academic school readiness, while exploring the possible moderator role played by child gender. The participants were 75 children who were assessed at two time points: when enrolled in the second preschool year (T1) and again 4 months before school entry (T2). The results showed an association between children's ToM abilities at T1 (but not at T2) and later academic readiness at T2, but only for girls, even after accounting for child IQ and maternal education. These findings support the idea that girls and boys can differ in how they use their ToM abilities in their daily life and highlight the relevance of further exploring gender-specific effects when investigating children's social cognition and school readiness.info:eu-repo/semantics/acceptedVersio

Variação estacional de preços para o figo comercializado na CEASA/RS.

Analisou-se a variação estacional de preços do figo maduro comercializado no atacado, junto a CEASA/RS, em uma série temporal de 10 anos. Empregou-se a metodologia das médias geométricas móveis sobre os preços médios mensais

Salivary oxytocin after play with parents predicts behavioural problems in preschool children

Background: Oxytocin (OXT) has attracted research interest for its potential involvement in many of the behavioural problems observed in childhood. Due to its logistical advantages, saliva is an attractive fluid to quantify neuropeptides in children. Salivary OXT has been suggested as a potential biomarker for psychopathology during childhood. However, several questions still remain about the extent to which, and under what conditions, concentrations of OXT in saliva can be reliably measured and are related to behavioural problems in preschool age children. Methods: Seven samples of saliva from 30 preschool children (17 girls) were collected in five different days at their homes. Three of the samples were collected by the children’s parents at baseline daily routine conditions, and four of the samples were collected by researchers during two home-visits: before and after two 15-minute dyadic play sessions (one with mothers and one fathers) between each individual parent and the child. Oxytocin concentrations were quantified by Radioimmunoassay with prior extraction. Children’s behavioural problems were assessed by the Caregiver-Teacher Report Form (C-TRF) questionnaire, completed by the child’s’ preschool teacher. Results: Salivary OXT measured in baseline samples could not predict any of the behavioural problems measured by the C-TRF. However, when measured after playing with parents salivary OXT showed a stronger pattern of negative correlations, specially with the depression and opposition scales of the C-TRF. Furthermore, salivary OXT was unlikely to be reliably measured using single sampling, but acceptable reliabilities were achieved when averaging several samples. Finally, the single measures of salivary OXT evoked after an episode of play with parents showed better reliabilities than collected at baseline. Conclusion: Measurements of OXT evoked after positive affect interactions with parents seem to capture aspects of the OXT system in young children that might be relevant for understanding the role of this system in children’s social behaviour.Fundação BIAL, FCT - Fundação para a Ciência e Tecnologiainfo:eu-repo/semantics/publishedVersio

Examining the Factorial Structure of the Maternal Separation Anxiety Scale in a Portuguese Sample

The increase in women's labor market participation emphasizes the importance of understanding maternal separation anxiety, that is, the unpleasant maternal emotional state, due to the actual or anticipated short-term separation from the child. Drawing on the insights of the attachment and psychoanalytic perspectives, the Maternal Separation Anxiety Scale (MSAS) was developed to overcome existing measurement gaps. However, prior research did not replicate its original three-factor structure in the contemporary context and in other cultural settings, using large samples composed of mothers of preschool children. This study aimed to examine the factorial structure of the MSAS in a sample of 597 Portuguese mothers of children aged 5-84 months who completed the questionnaire. The exploratory factor analysis (EFA) conducted in subsample 1 revealed a four-factor structure: Maternal Negative Feelings, Beliefs about Exclusive Maternal Care, Need of Proximity, and Perceptions of Separation Benefits for Children. Confirmatory factor analyses conducted in subsample 2 revealed that the original three-factor structure revealed a poor fit, whereas the four-factor solution (obtained in the EFA) revealed an acceptable fit. As in previous studies, our findings report deviations from the original three-factor structure of the MSAS. Three of the newly identified factors seem to reflect specific sub-dimensions that originally guided item development in the MSAS, namely, maternal negative feelings, maternal attitudes about the value of exclusive maternal care, and the need of proximity with the child. The last factor appears to represent a refinement of original items pertaining to perceptions about separation effects for children.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

Children's learning of non-adjacent dependencies using a web-based computer game setting

Infants show impressive speech decoding abilities and detect acoustic regularities that highlight the syntactic relations of a language, often coded via non-adjacent dependencies (NADs, e.g., is singing). It has been claimed that infants learn NADs implicitly and associatively through passive listening and that there is a shift from effortless associative learning to a more controlled learning of NADs after the age of 2 years, potentially driven by the maturation of the prefrontal cortex. To investigate if older children are able to learn NADs, Lammertink et al. (2019) recently developed a word-monitoring serial reaction time (SRT) task and could show that 6–11-year-old children learned the NADs, as their reaction times (RTs) increased then they were presented with violated NADs. In the current study we adapted their experimental paradigm and tested NAD learning in a younger group of 52 children between the age of 4–8 years in a remote, web-based, game-like setting (whack-a-mole). Children were exposed to Italian phrases containing NADs and had to monitor the occurrence of a target syllable, which was the second element of the NAD. After exposure, children did a “Stem Completion” task in which they were presented with the first element of the NAD and had to choose the second element of the NAD to complete the stimuli. Our findings show that, despite large variability in the data, children aged 4–8 years are sensitive to NADs; they show the expected differences in r RTs in the SRT task and could transfer the NAD-rule in the Stem Completion task. We discuss these results with respect to the development of NAD dependency learning in childhood and the practical impact and limitations of collecting these data in a web-based setting

Contact-induced spin polarization in carbon nanotubes

Motivated by the possibility of combining spintronics with molecular structures, we investigate the conditions for the appearance of spin-polarization in low-dimensional tubular systems by contacting them to a magnetic substrate. We derive a set of general expressions describing the charge transfer between the tube and the substrate and the relative energy costs. The mean-field solution of the general expressions provides an insightful formula for the induced spin-polarization. Using a tight-binding model for the electronic structure we are able to estimate the magnitude and the stability of the induced moment. This indicates that a significant magnetic moment in carbon nanotubes can be observed.Comment: To appear in Phys. Rev. B (2003

Caregivers’ perceived emotional and feeding responsiveness toward preschool children: Associations and paths of influence

Although there is a large body of research connecting emotion to eating behaviors, little is known about the role of caregivers’ responses to children’s emotions in the context of child feeding. The purpose of this study was to analyze the relation between caregivers’ emotional responsiveness and feeding responsiveness. The mothers of 137 children between 2 and 6 years of age reported on their responses to children’s negative emotions using the Coping with Children’s Negative Emotions Scale and on their feeding practices using the Comprehensive Feeding Practices Questionnaire. The results showed that mothers’ supportive emotion responses (e.g., problem-focused, emotion-focused, and expressive encouragement reactions) tend to be positively associated with responsive feeding practices (e.g., encouraging, modelling, and teaching healthy food-related behaviors). Instead, mothers’ unsupportive responses (e.g., distress, punitive and minimization reactions) tend to be positively associated with nonresponsive feeding practices (e.g., food as reward or to regulate emotions, and pressure to eat) and negatively associated with responsive feeding practices. Our results suggest that emotional and feeding responsiveness may be intertwined and that differences in parent’s emotional responsiveness may translate into differences in their feeding styles, setting the stage for parents’ use of positive vs. negative feeding practices.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio