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Safety climate in the service industries: the example of catering operations
The policy of self-regulation, which is central to occupational safety and health law in the United. Kingdom, is reviewed in the context of the catering industry. The influence of service and service quality on selfregulation and safety climate is considered. Some previously unpublished fiudings from a larger study on the factors affecting safety behaviour in lecturer chefs are reported and examined in terms of the above. It is suggested that the traditional autonomy and autocracy of chefs in catering organisations give them a pivotal role in self-regulation. In addition, the pursuit of service quality influences the chefs in certain ways, some of which may be negative in terms of safety management. It is argued that the pivotal role of chefs in delivering service quality can potentially adversely affect his or her role in safety management. Finally, it is proposed that the conflict between safety and production in the service industries may be more acute than in manufacturing because of the need for worker and, more particularly. supervisor concurrence rather than mere compliance with service quality strategies
Astrophysical Insights into Radial Velocity Jitter from an Analysis of 600 Planet-search Stars
Radial velocity (RV) detection of planets is hampered by astrophysical processes on the surfaces of stars that induce a stochastic signal, or "jitter," which can drown out or even mimic planetary signals. Here, we empirically and carefully measure the RV jitter of more than 600 stars from the California Planet Search sample on a star by star basis. As part of this process, we explore the activity–RV correlation of stellar cycles and include appendices listing every ostensibly companion-induced signal we removed and every activity cycle we noted. We then use precise stellar properties from Brewer et al. to separate the sample into bins of stellar mass and examine trends with activity and with evolutionary state. We find that RV jitter tracks stellar evolution and that in general, stars evolve through different stages of RV jitter: the jitter in younger stars is driven by magnetic activity, while the jitter in older stars is convectively driven and dominated by granulation and oscillations. We identify the "jitter minimum"—where activity-driven and convectively driven jitter have similar amplitudes—for stars between 0.7 and 1.7 M⊙ and find that more-massive stars reach this jitter minimum later in their lifetime, in the subgiant or even giant phases. Finally, we comment on how these results can inform future RV efforts, from prioritization of follow-up targets from transit surveys like TESS to target selection of future RV surveys
Linear Precoding in Cooperative MIMO Cellular Networks with Limited Coordination Clusters
In a cooperative multiple-antenna downlink cellular network, maximization of
a concave function of user rates is considered. A new linear precoding
technique called soft interference nulling (SIN) is proposed, which performs at
least as well as zero-forcing (ZF) beamforming. All base stations share channel
state information, but each user's message is only routed to those that
participate in the user's coordination cluster. SIN precoding is particularly
useful when clusters of limited sizes overlap in the network, in which case
traditional techniques such as dirty paper coding or ZF do not directly apply.
The SIN precoder is computed by solving a sequence of convex optimization
problems. SIN under partial network coordination can outperform ZF under full
network coordination at moderate SNRs. Under overlapping coordination clusters,
SIN precoding achieves considerably higher throughput compared to myopic ZF,
especially when the clusters are large.Comment: 13 pages, 5 figure
Method and device for detecting voids in low density material Patent
Method and photodetector device for locating abnormal voids in low density material
Surface Critical Behavior in Systems with Absorbing States
We present a general scaling theory for the surface critical behavior of
non-equilibrium systems with phase transitions into absorbing states. The
theory allows for two independent surface exponents which satisfy generalized
hyperscaling relations. As an application we study a generalized version of
directed percolation with two absorbing states. We find two distinct surface
universality classes associated with inactive and reflective walls. Our results
indicate that the exponents associated with these two surface universality
classes are closely connected.Comment: latex, 4 pages, to appear in PR
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