7,629 research outputs found
Quantum and Classical Dynamics of a BEC in a Large-Period Optical Lattice
We experimentally investigate diffraction of a Rb-87 Bose-Einstein condensate
from a 1D optical lattice. We use a range of lattice periods and timescales,
including those beyond the Raman-Nath limit. We compare the results to quantum
mechanical and classical simulations, with quantitative and qualitative
agreement, respectively. The classical simulation predicts that the envelope of
the time-evolving diffraction pattern is shaped by caustics: singularities in
the phase space density of classical trajectories. This behavior becomes
increasingly clear as the lattice period grows.Comment: 7 pages, 6 figure
Parallel hybrid textures of lepton mass matrices
We analyse the parallel hybrid texture structures in the charged lepton and
the neutrino sector. These parallel hybrid texture structures have physical
implications as they cannot be obtained from arbitrary lepton mass matrices
through weak basis transformations. The total sixty parallel hybrid texture
structures can be grouped into twelve classes, and all the hybrid textures in
the same class have identical physical implications. We examine all the twelve
classes under the assumption of non-factorizable phases in the neutrino mass
matrix. Five out of the total twelve classes are found to be phenomenologically
disallowed. We study the phenomenological implications of the allowed classes
for 1-3 mixing angle, Majorana and Dirac-type violating phases.
Interesting constraints on effective Majorana mass are obtained for all the
allowed classes.Comment: Physical Review D (To appear
Semantic priming in Russian monolingual and Russian (L1) – English (L2) bilingual speakers in a single word naming task: semantic priming in Russian
Identifying and exploring factors that influence bilingual language processing has been the topic of much psycholinguistic research. Semantic priming is typically used to examine semantic processing and refers to the phenomenon in which semantically related items (doctor-nurse) are processed faster and more accurately than semantically unrelated items (doctor-butter). The aim of the chapter is to address two key questions: 1) how the two languages of a bilingual are organised or stored and 2) how the two languages are processed. A review of the literature shows that there are currently no theoretical frameworks that explain Russian monolingual or Russian (L1)-English (L2) bilingual storage or processing. Monolingual Russian speakers and bilingual Russian (L1)-English (L2) speaking university students were asked to name target words under related or unrelated conditions. The results show that the magnitude of the semantic priming effect was determined by L2 proficiency. The implications for these findings is discussed within the current bilingual theoretical models
Age of Acquisition (AoA) effect in monolingual Russian and bilingual Russian (L1) - English (L2) speakers in a free recall task
AoA is a unique psycholinguistic variable because of its link to the semantic architecture of the mental lexicon (e.g., Brysbaert, Wijnendaele & de Deyne, 2000). The role of AoA on free recall has been examined in English (Coltheart & Winograd, 1986; Dewhurst, Hitch & Barry, 1998) and recently in Turkish (Raman, Raman, Ikier et al, under revision) with contradictory outcomes. While an overall advantage was found for late acquired items in English, the contrary was reported in Turkish. Furthermore, this effect appeared to be modulated by frequency and whether items were presented in pure or mixed lists. The present study extends Raman et al study to monolingual Russian and bilingual Russian (L1) – English (L2) speakers in order to understand the extent to which AoA affects free recall. One interesting aspect of Russian writing system is that it consists of Cyrillic and Roman letters, hence creating a shared orthographic medium in Russian-English bilinguals. Participants were allocated to either picture or word condition and subsequently to either pure list or mixed list condition. Both monolingual Russian (N=42) and bilingual (N=40) Russian (L1) – English (L2) data show a robust main effect for AoA in free recall irrespective of list type for words and for pictures and no significant interactions. Overall, early acquired words and pictures had an advantage over late acquired items. These findings are contrary to what has been reported in the literature for monolingual English speakers (Dewhurst et al, 1998) but in line with findings for Turkish (Raman et al, under revision) and will be discussed within the monolingual and bilingual theoretical frameworks
The Nuclear Science References (NSR) Database and Web Retrieval System
The Nuclear Science References (NSR) database together with its associated
Web interface, is the world's only comprehensive source of easily accessible
low- and intermediate-energy nuclear physics bibliographic information for more
than 200,000 articles since the beginning of nuclear science. The
weekly-updated NSR database provides essential support for nuclear data
evaluation, compilation and research activities. The principles of the database
and Web application development and maintenance are described. Examples of
nuclear structure, reaction and decay applications are specifically included.
The complete NSR database is freely available at the websites of the National
Nuclear Data Center http://www.nndc.bnl.gov/nsr and the International Atomic
Energy Agency http://www-nds.iaea.org/nsr.Comment: 16 pages, 5 figure
The Partnership Imperative: Community Colleges, Employers, and Americas Chronic Skills Gap
This report examines the state of collaboration between community colleges and business leaders and calls on employers to more actively partner with educators.Educators and employers are failing to meet the challenge: how to equip enough workers with the skills needed to keep the U.S. economy competitive and fill the millions of vacant positions. Employers complain they cannot find the talent they need—in terms of quantity, quality, and diversity—and critical middle-skills positions go unfilled. At the same time, many students emerge from the community college system unable to find employment in their field of study or at a living wage. Educators struggle to engage employers—in curriculum development; information sharing on fast-changing technical and foundational skills requirements for middle-skills positions; and more.In order to diagnose the problem, the Project on Managing the Future of Work launched a multiyear, multi-method research initiative combining background research and interviews with community college leaders and business executives across the country. The Project then partnered with the American Association of Community Colleges to conduct the first-ever exhaustive survey on the state and trajectory of the partnership between educators and employers, based on a framework of more than 40 concrete actions designed to build a work-ready workforce
Effects of physical activity on debilitating behaviours in 13- to 20-year-old males with severe autism spectrum disorder
The presented study investigated the extent to which engaging in a therapeutic sporting programme in males with severe Autism Spectrum Disorder (ASD) improves the debilitating behaviours commonly associated with ASD. Furthermore, the views of parents of the autistic participants were assessed concerning the effectiveness of the programme. Participants were eight 13-20 year old males born in the UK from a school and sports college for pupils with severe learning difficulties. The selection was using volunteer sampling from the “Monday Club” initiative, run by Saracens Sports Foundation in partnership with a local School and specialist Sports College. The Gilliam Autism Rating Scale (GARS-3) was administered to identify and measure the severity of ASD behaviours at four time periods namely: at programme entry as the baseline (T1), a second time after 8 weeks (T2), a third time after sixteen weeks (T3) and a fourth time post programme (T4). The results showed that for the more severe cases of ASD (Autism Index >101) there was no positive change in subscale performance from Time1 to Time2. For milder cases (Autism Index 71-100) there were subtle non-significant improvements on the subscale scores from Time1 to Time2. Of the 6 subscales at Time2, Emotional Responses (ER), Cognitive Style (CS) and Maladaptive Speech (MS) approached significance at the p = 0.05 level. At Time3 and Time4, there was also no statistically significant improvement in ASD behaviours compared to the baseline for either condition. Finally parents’ were “very satisfied” with their child’s participation in the physical activity programme
The eigenspectra of Indian musical drums
In a family of drums used in the Indian subcontinent, the circular drum head
is made of material of non-uniform density. Remarkably, and in contrast to a
circular membrane of uniform density, the low eigenmodes of the non-uniform
membrane are harmonic. In this work we model the drum head by a non-uniform
membrane whose density varies smoothly between two prescribed values. Using a
Fourier-Chebyshev spectral collocation method we obtain the eigenmodes and
eigenvalues of the drum head. For a suitable choice of parameters, which we
find by optimising a cost function, the eigenspectra obtained from our model
are in excellent agreement with experimental values. Our model and the
numerical method should find application in numerical sound synthesis
- …