Helicopter cabin noise: Methods of source and path identification and characterization

Internal noise sources in a helicopter are considered. These include propulsion machinery, comprising engine and transmission, and turbulent boundary layer effects. It is shown that by using relatively simple concepts together with careful experimental work it is possible to generate reliable data on which to base the design of high performance noise control treatments

Exploring the challenges of implementing e-health: a protocol for an update of a systematic review of reviews.

There is great potential for e-health to deliver cost-effective, quality healthcare and spending on e-health systems by governments and healthcare systems is increasing worldwide. However, the literature often describes problematic and unsuccessful attempts to implement these new technologies into routine clinical practice. To understand and address the challenges of implementing e-health, a systematic review was conducted in 2009, which identified several conceptual barriers and facilitators to implementation. As technology is rapidly changing and new e-health solutions are constantly evolving to meet the needs of current practice, an update of this review is deemed necessary to understand current challenges to the implementation of e-health. This research aims to identify, summarise and synthesise currently available evidence, by undertaking a systematic review of reviews to explore the barriers and facilitators to implementing e-health across a range of healthcare settings

The effect of a planet on the dust distribution in a 3D protoplanetary disk

Aims: We investigate the behaviour of dust in protoplanetary disks under the action of gas drag in the presence of a planet. Our goal is twofold: to determine the spatial distribution of dust depending on grain size and planet mass, and therefore to provide a framework for interpretation of coming observations and future studies of planetesimal growth. Method: We numerically model the evolution of dust in a protoplanetary disk using a two-fluid (gas + dust) Smoothed Particle Hydrodynamics (SPH) code, which is non-self-gravitating and locally isothermal. The code follows the three dimensional distribution of dust in a protoplanetary disk as it interacts with the gas via aerodynamic drag. In this work, we present the evolution of a minimum mass solar nebula (MMSN) disk comprising 1% dust by mass in the presence of an embedded planet. We run a series of simulations which vary the grain size and planetary mass to see how they affect the resulting disk structure. Results: We find that gap formation is much more rapid and striking in the dust layer than in the gaseous disk and that a system with a given stellar, disk and planetary mass will have a completely different appearance depending on the grain size. For low mass planets in our MMSN disk, a gap can open in the dust disk while not in the gas disk. We also note that dust accumulates at the external edge of the planetary gap and speculate that the presence of a planet in the disk may enhance the formation of a second planet by facilitating the growth of planetesimals in this high density region.Comment: 13 pages, 12 figures. Accepted for publication in Astronomy & Astrophysic

Nuclear effects in photoproduction of heavy quarks and vector mesons in ultraperipheral PbPb and pPb collisions at the LHC

The comparison of photoproduction cross sections for $c\bar{c}$ and b-b(bar) in PbPb and pPb collisions can give sensitivity to nuclear shadowing effects. The photoproduction of vector mesons is even more sensitive to the underlying gluon distributions. In this study we present the cross sections and rapidity dependence of the photoproduction of heavy quarks and exclusive production of vector mesons in ultraperipheral pPb and PbPb collisions at the Large Hadron Collider at sqrt(s_NN)=5 TeV and sqrt(s_NN)=2.76$TeV, respectively. The potentials of using these processes for constraining nuclear gluon shadowing are explored. It is found that photoproduction of$J/\psi$and$\Upsilon$ in PbPb collisions in particular exhibit very good sensitivity to gluon shadowing.Comment: 4 pages, 4 figure

A microscopic approach to nonlinear Reaction-Diffusion: the case of morphogen gradient formation

We develop a microscopic theory for reaction-difusion (R-D) processes based on a generalization of Einstein's master equation with a reactive term and we show how the mean field formulation leads to a generalized R-D equation with non-classical solutions. For the $n$-th order annihilation reaction $A+A+A+...+A\rightarrow 0$, we obtain a nonlinear reaction-diffusion equation for which we discuss scaling and non-scaling formulations. We find steady states with either solutions exhibiting long range power law behavior (for $n>\alpha$) showing the relative dominance of sub-diffusion over reaction effects in constrained systems, or conversely solutions (for $n<\alpha<n+1$) with finite support of the concentration distribution describing situations where diffusion is slow and extinction is fast. Theoretical results are compared with experimental data for morphogen gradient formation.Comment: Article, 10 pages, 5 figure

Morphological evidence for a sea-ice origin for Elysium Planitia platy terrain

Abstract not available

Biodiversity of Spongosorites coralliophaga (Stephens, 1915) on coral rubble at two contrasting cold-water coral reef settings

The authors would like to thank Bill Richardson (Master), the crew of the RRS James Cook, Will Handley and the Holland-I ROV team. We also thank all the specialists in taxonomy that provided important help with identification of species: Professor Paul Tyler (ophiuroids), Dr. Tammy Horton (amphipods), Dr. Graham Oliver (bivalves), Dr. Rob van Soest (sponges), Susan Chambers, Peter Garwood, Sue Hamilton, Raimundo Blanco Pérez (polychaetes). Also we would like to thank Val Johnston (University of Aberdeen) for her contribution to cruise preparations and John Polanski (University of Aberdeen) for his help onboard the RRS James Cook. Special thanks to Dr. Alexios P. Lolas (University of Thessaly, Greece) for all the artwork. Funding for the JC073 cruise was provided by the Natural Environment Research Council (NERC) UK Ocean Acidification (UKOA) research programme’s Benthic Consortium project (NE/H017305/1 to JMR). JMR acknowledges support from Heriot-Watt University’s Environment and Climate Change theme. GK was funded by a Marine Alliance for Science and Technology for Scotland (MASTS) Ph.D. scholarship.Peer reviewedPublisher PD

Electronic control/display interface technology

An effort to produce a representative workstation for the Space Station Data Management Test Bed that provides man/machine interface design options for consolidating, automating, and integrating the space station work station, and hardware/software technology demonstrations of space station applications is discussed. The workstation will emphasize the technologies of advanced graphics engines, advanced display/control medias, image management techniques, multifunction controls, and video disk utilizations

Estimation over Communication Networks: Performance Bounds and Achievability Results

This paper considers the problem of estimation over communication networks. Suppose a sensor is taking measurements of a dynamic process. However the process needs to be estimated at a remote location connected to the sensor through a network of communication links that drop packets stochastically. We provide a framework for computing the optimal performance in the sense of expected error covariance. Using this framework we characterize the dependency of the performance on the topology of the network and the packet dropping process. For independent and memoryless packet dropping processes we find the steady-state error for some classes of networks and obtain lower and upper bounds for the performance of a general network. Finally we find a necessary and sufficient condition for the stability of the estimate error covariance for general networks with spatially correlated and Markov type dropping process. This interesting condition has a max-cut interpretation

Complementarity and diversity in a soluble model ecosystem

Complementarity among species with different traits is one of the basic processes affecting biodiversity, defined as the number of species in the ecosystem. We present here a soluble model ecosystem in which the species are characterized by binary traits and their pairwise interactions follow a complementarity principle. Manipulation of the species composition, and so the study of its effects on the species diversity is achieved through the introduction of a bias parameter favoring one of the traits. Using statistical mechanics tools we find explicit expressions for the allowed values of the equilibrium species concentrations in terms of the control parameters of the model