501 research outputs found
Characterisation of the entomopathogenic nematode Heterorhabditis (Nematoda : Heterorhabditidae) from Ireland and Britain by molecular and cross-breeding techniques, and the occurrence of the genus in these islands
Des examens de sol ont été effectués en Irlande et en Grande-Bretagne pour rechercher les nématodes du genre #Heterorhabditis. Des échantillons des sols prélevés sur des sites sablonneux furent pourvus de larves de #Galleria mellonella comme appâts. Des #Heterorhabditis furent collectés sur 18 sites sur 169 en Irlande, 2 sur 51 dans le nord de l'Ecosse et 9 sur 20 dans le sud du Pays de Galle. Tous les sites positifs sont situés sur le littoral ; aucun #Heterorhabditis n'a été détecté dans les échantillons prélevés dans 40 sites situés à l'intérieur des terres. La totalité des 76 isolats recueillis au cours de ces analyses ont été identifiés comme appartenant au groupe irlandais d'#Heterorhabditis, à l'aide de méthodes de concentration isoélectrique, de restriction de l'ADN et d'hybridation. Aucun #Heterohabditis appartenant au groupe de l'Europe du nord-ouest n'a été recueilli. Cependant, un isolat recueilli par d'autres chercheurs et provenant du sud de l'Angleterre a été identifié comme appartenant à ce groupe. Les membres du groupe irlandais ne se croisent généralement pas avec les membres du groupe de l'Europe du nord-ouest, bien que des juvéniles infestants fertiles aient été produits dans un nombre limité (3/15) de croisements entre ces groupes. (Résumé d'auteur
Bose-Condensed Gases in a 1D Optical Lattice at Finite Temperatures
We study equilibrium properties of Bose-Condensed gases in a one-dimensional
(1D) optical lattice at finite temperatures. We assume that an additional
harmonic confinement is highly anisotropic, in which the confinement in the
radial directions is much tighter than in the axial direction. We derive a
quasi-1D model of the Gross-Pitaeavkill equation and the Bogoliubov equations,
and numerically solve these equations to obtain the condensate fraction as a
function of the temperature.Comment: Comments: 6 pages, 3 figures, submitted to Quantum Fluids and Solids
Conference (QFS 2006
Correlates of light and moderate-to-vigorous objectively measured physical activity in four-year-old children
Correlates of physical activity (PA) are hypothesized to be context and behaviour specific, but there is limited evidence of this in young children. The aim of the current study is to investigate associations between personal, social and environmental factors and objectively measured light and moderate-to-vigorous PA (LPA and MVPA, respectively) in four-year-old children.Cross-sectional data were used from the Southampton Women's Survey, a UK population-based longitudinal study. Four-year old children (n = 487, 47.0% male) had valid PA data assessed using accelerometry (Actiheart) and exposure data collected with a validated maternal questionnaire (including data on child personality, family demographics, maternal behaviour, rules and restrictions, and perceived local environment). Linear regression modelling was used to analyse associations with LPA and MVPA separately, interactions with sex were explored.LPA minutes were greater in children whose mothers reported more PA (vs. inactive: regression coefficient±standard error: 6.70±2.94 minutes), and without other children in the neighbourhood to play with (-6.33±2.44). MVPA minutes were greater in children with older siblings (vs. none: 5.81±2.80) and those whose mothers used active transport for short trips (vs. inactive: 6.24±2.95). Children accumulated more MVPA in spring (vs. winter: 9.50±4.03) and, in boys only, less MVPA with availability of other children in the neighbourhood (-3.98±1.70).Young children's LPA and MVPA have differing associations with a number of social and environmental variables. Interventions targeting PA promotion in young children outside of formal care settings should consider including intensity specific factors
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Multi-mode traffic-induced vibrations in composite ladder-deck bridges under heavy moving vehicles
Composite (steel-concrete) ladder-decks represent one of the most common solutions in road bridges nowadays. In these structures the Serviceability Limit State (SLS) of vibrations is traditionally ignored or roughly addressed by means of simple static deflection-based approaches, inherently assuming that the vibrations are controlled by the fundamental longitudinal mode. This work demonstrates that a wide range of high-order vibrational modes, involving the transverse flexure of the slab between longitudinal girders, govern the accelerations recorded in the deck and inside the vehicles. In addition, a new methodology for analysing the Vehicle–Bridge Interaction is proposed, including the approaching platforms, the transition slabs, and the bridge joints. The results suggest that the riding comfort for vehicle users is specially affected by direct effects on the wheels, like the road roughness and possible construction misalignments at the bridge joints, as well as low-frequency vibrations coming from the deck in short or slender bridges. The filtering effects resulting from the average of the response in time and in space when calculating the root mean square acceleration are also explored, and new design parameters are provided. In addition, several structural features (such as the depth and spacing of the longitudinal and transverse steel beams, the thickness of the concrete slab, and the stiffness of the cantilever cross beams at the diaphragm sections) have been studied, and a set of new design criteria has been established. It has been demonstrated that the transverse flexibility of the deck (specially influenced by the support conditions and the slab thickness) is critically important for the users’ (pedestrians and vehicle passengers) comfort, as it controls the aforementioned high-order vibrational modes which govern the dynamic response
The use of an e-learning constructivist solution in workplace learning
We wished to investigate whether an e-learning approach which uses constructivist principles can be successfully applied to train employees in a highly specialised skill thought to require expert individuals and extensive prolonged training. The approach involved the development of an e-learning package which included simulations and interactivity, then experimental testing in a case study workplace environment with the collection of both quantitative and qualitative data to assess the effectiveness of the package. Our study shows that this e-learning strategy improved the skills of the inexperienced
operator significantly. We therefore propose that such programmes could be used as a work based training aid and used as a model system for the training of employees in complex skilled tasks in the workplace. This research demonstrates that the e-learning can be applied outside the traditional learning environment to train unskilled employees to undertake complex practical tasks which traditionally would involve prohibitively expensive instruction. This work also illustrates that simulations and interactivity are powerful tools in the design of successful e-learning packages in preparing learners for real world practical situations. Finally this study shows that workplace learners can be better served by elearning environments rather than conventional training as they allow asynchronous learning and private study which are valued by employees who have other demands on their time and are more comfortable receiving tuition privately Relevance to industry: E-learning using constructivist principles, and incorporating simulations and interactivity can be used successfully in the training of highly specialised and skilled tasks required in the
modern workplace
Prevalence of sexual harassment among Norwegian female elite athletes in relation to sport type
Although it is often assumed that the prevalence of sexual harassment is different in different sports, this assumption has not been empirically tested. This study considers whether the experience of sexual harassment varies by sport. The female elite athletes (N = 553) in the study participated in 56 different sport disciplines. These were grouped as follows :1) team or individual sports; 2) extent to which clothing required for competition is revealing ; 3) gender structure (male-or female dominated membership statistics); and 4) gender culture (masculine, gender-neutral, or feminine). The data show that sexual harassment occurs in every sport group. Female elite athletes who participated in ‘masculine’ sports appear to experience more harassment than women in the other groups. We conclude that, when it comes to female athletes’ experiences of sexual harassment, sport type matters far less than sport participation per se
A particle-number-conserving Bogoliubov method which demonstrates the validity of the time-dependent Gross-Pitaevskii equation for a highly condensed Bose gas
The Bogoliubov method for the excitation spectrum of a Bose-condensed gas is
generalized to apply to a gas with an exact large number of particles.
This generalization yields a description of the Schr\"odinger picture field
operators as the product of an annihilation operator for the total number
of particles and the sum of a ``condensate wavefunction'' and a phonon
field operator in the form when the field operator acts on the N particle subspace. It
is then possible to expand the Hamiltonian in decreasing powers of ,
an thus obtain solutions for eigenvalues and eigenstates as an asymptotic
expansion of the same kind. It is also possible to compute all matrix elements
of field operators between states of different N.Comment: RevTeX, 11 page
Investigation of the distribution of localised and extended states in amorphous MoOx
Amorphous films of MoOx have both structural disorder and also chemical disorder for x<3. We have shown that this disorder can introduce localised states in thin films and have shown that the existence of localised states can be deduced from the XPS data that identifies the relevant occupations of different ionisation states of the Mo ions. This effect, which depends on both the oxygen concentration and the method of fabrication, is more important than electron-electron interactions in producing the observed localisation. We have also shown that magneto-optical dichroism is also a powerful technique to determine the energy distribution of localised and delocalised states
Making things happen : a model of proactive motivation
Being proactive is about making things happen, anticipating and preventing problems, and seizing opportunities. It involves self-initiated efforts to bring about change in the work environment and/or oneself to achieve a different future. The authors develop existing perspectives on this topic by identifying proactivity as a goal-driven process involving both the setting of a proactive goal (proactive goal generation) and striving to achieve that proactive goal (proactive goal striving). The authors identify a range of proactive goals that individuals can pursue in organizations. These vary on two dimensions: the future they aim to bring about (achieving a better personal fit within one’s work environment, improving the organization’s internal functioning, or enhancing the organization’s strategic fit with its environment) and whether the self or situation is being changed. The authors then identify “can do,” “reason to,” and “energized to” motivational states that prompt proactive goal generation and sustain goal striving. Can do motivation arises from perceptions of self-efficacy, control, and (low) cost. Reason to motivation relates to why someone is proactive, including reasons flowing from intrinsic, integrated, and identified motivation. Energized to motivation refers to activated positive affective states that prompt proactive goal processes. The authors suggest more distal antecedents, including individual differences (e.g., personality, values, knowledge and ability) as well as contextual variations in leadership, work design, and interpersonal climate, that influence the proactive motivational states and thereby boost or inhibit proactive goal processes. Finally, the authors summarize priorities for future researc
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