Atom gratings produced by large angle atom beam splitters

An asymptotic theory of atom scattering by large amplitude periodic potentials is developed in the Raman-Nath approximation. The atom grating profile arising after scattering is evaluated in the Fresnel zone for triangular, sinusoidal, magneto-optical, and bichromatic field potentials. It is shown that, owing to the scattering in these potentials, two \QTR{em}{groups} of momentum states are produced rather than two distinct momentum components. The corresponding spatial density profile is calculated and found to differ significantly from a pure sinusoid.Comment: 16 pages, 7 figure

Atom-optics hologram in the time domain

The temporal evolution of an atomic wave packet interacting with object and reference electromagnetic waves is investigated beyond the weak perturbation of the initial state. It is shown that the diffraction of an ultracold atomic beam by the inhomogeneous laser field can be interpreted as if the beam passes through a three-dimensional hologram, whose thickness is proportional to the interaction time. It is found that the diffraction efficiency of such a hologram may reach 100% and is determined by the duration of laser pulses. On this basis a method for reconstruction of the object image with matter waves is offered.Comment: RevTeX, 13 pages, 8 figures; minor grammatical change

The contribution of corporate social responsibility to organisational commitment

This study investigates the relationship between organizational commitment and employee perceptions of corporate social responsibility (CSR) within a model that draws on social identity theory. Specifically, we examine the impact of three aspects of socially responsible behaviour on organizational commitment: employee perceptions of corporate social responsibility in the community, procedural justice in the organization and the provision of employee training. The relationship between organizational commitment and each aspect of CSR is investigated within a model that distinguishes between genders and includes a set of control variables that is drawn from the commitment literature (Meyer et al., 2002). The analysis is based on a sample of 4,712 employees drawn from a financial services company. The results emphasize the importance of gender variation and suggest both that external CSR is positively related to organizational commitment and that the contribution of CSR to organizational commitment is at least as great as job satisfaction.19 page(s

Simple rules guide dragonfly migration

Every year billions of butterflies, dragonflies, moths and other insects migrate across continents, and considerable progress has been made in understanding population-level migratory phenomena. However, little is known about destinations and strategies of individual insects. We attached miniaturized radio transmitters (ca 300 mg) to the thoraxes of 14 individual dragonflies (common green darners, Anax junius) and followed them during their autumn migration for up to 12 days, using receiver-equipped Cessna airplanes and ground teams. Green darners exhibited distinct stopover and migration days. On average, they migrated every 2.9±0.3 days, and their average net advance was 58±11 km in 6.1±0.9 days (11.9±2.8 km d(−1)) in a generally southward direction (186±52°). They migrated exclusively during the daytime, when wind speeds were less than 25 km h(−1), regardless of wind direction, but only after two nights of successively lower temperatures (decrease of 2.1±0.6 °C in minimum temperature). The migratory patterns and apparent decision rules of green darners are strikingly similar to those proposed for songbirds, and may represent a general migration strategy for long-distance migration of organisms with high self-propelled flight speeds