Adiabatic projection method for scattering and reactions on the lattice

We demonstrate and test the adiabatic projection method, a general new framework for calculating scattering and reactions on the lattice. The method is based upon calculating a low-energy effective theory for clusters which becomes exact in the limit of large Euclidean projection time. As a detailed example we calculate the adiabatic two-body Hamiltonian for elastic fermion-dimer scattering in lattice effective field theory. Our calculation corresponds to neutron-deuteron scattering in the spin-quartet channel at leading order in pionless effective field theory. We show that the spectrum of the adiabatic Hamiltonian reproduces the spectrum of the original Hamiltonian below the inelastic threshold to arbitrary accuracy. We also show that the calculated s-wave phase shift reproduces the known exact result in the continuum and infinite-volume limits. When extended to more than one scattering channel, the adiabatic projection method can be used to calculate inelastic reactions on the lattice in future work.Comment: 17 pages, 4 figures, version to appear in Eur. Phys. J.

Effective Field Theory for Bound State Reflection

Elastic quantum bound-state reflection from a hard-wall boundary provides direct information regarding the structure and compressibility of quantum bound states. We discuss elastic quantum bound-state reflection and derive a general theory for elastic reflection of shallow dimers from hard-wall surfaces using effective field theory. We show that there is a small expansion parameter for analytic calculations of the reflection scattering length. We present a calculation up to second order in the effective Hamiltonian in one, two, and three dimensions. We also provide numerical lattice results for all three cases as a comparison with our effective field theory results. Finally, we provide an analysis of the compressibility of the alpha particle confined to a cubic lattice with vanishing Dirichlet boundaries.Comment: 43 pages, 9 figures, 16 tables, published versio

Non-adjacent dependency learning in infancy, and its link to language development.

To acquire language, infants must learn how to identify words and linguistic structure in speech. Statistical learning has been suggested to assist both of these tasks. However, infants’ capacity to use statistics to discover words and structure together remains unclear. Further, it is not yet known how infants' statistical learning ability relates to their language development. We trained 17-month-old infants on an artificial language comprising non- adjacent dependencies, and examined their looking times on tasks assessing sensitivity to words and structure using an eye-tracked head-turn-preference paradigm. We measured infants’ vocabulary size using a Communicative Development Inventory (CDI) concurrently and at 19, 21, 24, 25, 27, and 30 months to relate performance to language development. Infants could segment the words from speech, demonstrated by a significant difference in looking times to words versus part-words. Infants’ segmentation performance was significantly related to their vocabulary size (receptive and expressive) both currently, and over time (receptive until 24 months, expressive until 30 months), but was not related to the rate of vocabulary growth. The data also suggest infants may have developed sensitivity to generalised structure, indicating similar statistical learning mechanisms may contribute to the discovery of words and structure in speech, but this was not related to vocabulary size

Differential effects of manganese and alcohol on mammalian pubertal development

The age at which the onset of puberty begins is variable and depends on a complex series of centrally mediated events resulting in an increased pulsatile pattern of luteinizing hormone releasing hormone (LHRH) secretion from the hypothalamus. This changing pattern in LHRH secretion at puberty has been associated with the removal of an inhibitory tone and/or with the developmental responsiveness to excitatory components within the hypothalamus. In recent years much progress has been made in identifying inhibitory components such as gamma aminobutyric acid and the opioid peptides (1, 2), as well as stimulatory components such as excitatory amino acids (3), leptin (4), transforming growth factor a (TGFa; 5), insulin like growth factor -1 (IGF-1; 6), KiSS-1/kisspeptin (7) and manganese (Mn; 8). Importantly, all of these substances are capable of influencing LHRH secretion at puberty. The increased release of LHRH at puberty appears to utilize an interactive participation of neural circuits and glial cells (9). Furthermore, it is well known that neuronal and glial functions can be further influenced by peripheral metabolic signals, genetic and environmental influences, as well as drugs of abuse. Thus, any substance, whether it be endogenous or exogenous, that is capable of stimulating or inhibiting prepubertal LHRH secretion could have an impact on pubertal development. In recent years we have studied the actions of manganese chloride (MnCl₂), IGF-1 and alcohol (ALC) on puberty related events. This article will review our current understanding of the positive and/or negative influences of each of these substances on pubertal processes in females. Specifically, we will describe the positive action of MnCl₂ on LHRH release, and point out the potential beneficial and harmful effects of prepubertal exposure to low but elevated levels of this element. We will also describe the positive role of IGF-1 on puberty, and the negative action of prepubertal ALC exposure during pubertal development. Furthermore, we will discuss the actions and interactions between ALC and IGF-1 on puberty related genes, hormonal secretions and the timing of female puberty.Sociedad Argentina de Fisiologí

The Impact of Shared Book Reading on Children’s Language Skills: A Meta-Analysis

Shared book reading is thought to have a positive impact on young children's language development, with shared reading interventions often run in an attempt to boost children's language skills. However, despite the volume of research in this area, a number of issues remain outstanding. The current meta-analysis explored whether shared reading interventions are equally effective (a) across a range of study designs; (b) across a range of different outcome variables; and (c) for children from different SES groups. It also explored the potentially moderating effects of intervention duration, child age, use of dialogic reading techniques, person delivering the intervention and mode of intervention delivery. Our results show that, while there is an effect of shared reading on language development, this effect is smaller than reported in previous meta-analyses (g‾  = 0.194, p = .002). They also show that this effect is moderated by the type of control group used and is negligible in studies with active control groups (g‾  = 0.028, p = .703). Finally, they show no significant effects of differences in outcome variable (ps ≥ .286), socio-economic status (p = .658), or any of our other potential moderators (ps ≥ .077), and non-significant effects for studies with follow-ups (g‾  = 0.139, p = .200). On the basis of these results, we make a number of recommendations for researchers and educators about the design and implementation of future shared reading interventions

Does the understanding of complex dynamic events at 10 months predict vocabulary development?

By the end of their first year, infants can interpret many different types of complex dynamic visual events, such as caused-motion, chasing, and goal-directed action. Infants of this age are also in the early stages of vocabulary development, producing their first words at around 12 months. The present work examined whether there are meaningful individual differences in infants’ ability to represent dynamic causal events in visual scenes, and whether these differences influence vocabulary development. As part of the longitudinal Language 0–5 Project, 78 10-month-old infants were tested on their ability to interpret three dynamic motion events, involving (a) caused-motion, (b) chasing behaviour, and (c) goal-directed movement. Planned analyses found that infants showed evidence of understanding the first two event types, but not the third. Looking behaviour in each task was not meaningfully related to vocabulary development, nor were there any correlations between the tasks. The results of additional exploratory analyses and simulations suggested that the infants’ understanding of each event may not be predictive of their vocabulary development, and that looking times in these tasks may not be reliably capturing any meaningful individual differences in their knowledge. This raises questions about how to convert experimental group designs to individual differences measures, and how to interpret infant looking time behaviour

Common and specific amygdala-function perturbations in 2 depressed versus anxious adolescents

Context: Few studies directly compare amygdala function in depressive and anxiety disorders. 43 Data from longitudinal research emphasize the need for such studies in adolescents. 44 Objective: To compare amygdala response to varying attention and emotion conditions among 45 adolescents with Major Depressive Disorder (MDD) or anxiety disorders, relative to adolescents 46 with no psychopathology. 47 Design: Case-Control-Study. 48 Setting: Government Clinical Research Institute. 49 Participants: Eighty-seven adolescents matched on age, gender, intelligence, and social class: 26 50 with Major Depressive Disorder (MDD; 14 with and 12 without anxiety disorders), 16 with 51 anxiety disorders but no depression, and 45 with no psychopathology. 52 Main Outcome Measures: Blood oxygenated level dependent signal in the amygdala, measured 53 using event-related functional magnetic resonance imaging. During imaging, participants viewed 54 facial expressions (neutral, fearful, angry, happy) while attention was constrained (afraid, 55 hostility, nose width ratings) or unconstrained (passive-viewing). 56 Results: Left and right amygdala activation differed as a function of diagnosis, facial expression, 57 and attention-condition both when comorbid MDD/anxiety patients were included and excluded 58 (group-by-emotion-by-attention interactions: p-values≤.03). Focusing on fearful-face-viewing 59 events, anxiety and MDD patients both differed in amygdala responses from healthy participants 60 and from each other during passive-viewing. However, both MDD and anxiety patients, relative 61 to healthy participants, exhibited similar signs of amygdala hyper-activation to fearful faces when 62 rating subjectively experienced fear. 63 Conclusions: Adolescent MDD and anxiety disorders exhibit common and distinct functional 64 neural correlates during face processing. Attention modulates the degree to which common or 65 distinct amygdala perturbations manifest in these patient groups, relative to healthy peers

Learning to generalise but not segment an artificial language at 17 months predicts children’s language skills 3 years later

We investigated whether learning an artificial language at 17 months was predictive of children’s natural language vocabulary and grammar skills at 54 months. Children at 17 months listened to an artificial language containing non-adjacent dependencies, and were then tested on their learning to segment and to generalise the structure of the language. At 54 months, children were then tested on a range of standardised natural language tasks that assessed receptive and expressive vocabulary and grammar. A structural equation model demonstrated that learning the artificial language generalisation at 17 months predicted language abilities – a composite of vocabulary and grammar skills – at 54 months, whereas artificial language segmentation at 17 months did not predict language abilities at this age. Artificial language learning tasks – especially those that probe grammar learning – provide a valuable tool for uncovering the mechanisms driving children’s early language development