Performance of the distributed central analysis in BaBar

The total dataset produced by the BaBar experiment at the Stanford Linear Accelerator Center (SLAC) currently comprises roughly$3times 10^9$data events and an equal amount of simulated events, corresponding to 23 Tbytes of real data and 51 Tbytes simulated events. Since individual analyses typically select a very small fraction of all events, it would be extremely inefficient if each analysis had to process the full dataset. A first, centrally managed analysis step is therefore a common pre-selection (‘skimming’) of all data according to very loose, inclusive criteria to facilitate data access for later analysis. Usually, there are common selection criteria for several analysis. However, they may change over time, e.g., when new analyses are developed. Currently,$cal

A High Phase Advance Damped and Detuned Structure for the Main Linacs of Clic

The main accelerating structures for the CLIC are designed to operate at an average accelerating gradient of 100 MV/m. The accelerating frequency has been optimised to 11.994 GHz with a phase advance of 2{\pi}/3 of the main accelerating mode. The moderately damped and detuned structure (DDS) design is being studied as an alternative to the strongly damped WDS design. Both these designs are based on the nominal accelerating phase advance. Here we explore high phase advance (HPA) structures in which the group velocity of the rf fields is reduced compared to that of standard (2{\pi}/3) structures. The electrical breakdown strongly depends on the fundamental mode group velocity. Hence it is expected that electrical breakdown is less likely to occur in the HPA structures. We report on a study of both the fundamental and dipole modes in a CLIC_DDS_HPA structure, designed to operate at 5{\pi}/6 phase advance per cell. Higher order dipole modes in both the standard and HPA structures are also studied

A survey of factors influencing career preference in new-entrant and exiting medical students from four UK medical schools

Our thanks to Professor Gillian Needham and Dr Murray Lough for their encouragement and support, and their comments on an earlier draft of this manuscript. Our thanks also to NHS Education for Scotland [NES] for funding, and the Scottish Medical Deans Education Group [SMDEG] for supporting this project. We are grateful to all the students who gave their time to complete the survey questionnaire and to those who helped organise and carry out data collection.Peer reviewedPublisher PD

Climate change impacts on water for irrigated horticulture in the Vale of Evesham. Final Report

This project has undertaken a scoping review and assessment of the impacts of climate change on irrigated horticulture in the Vale of Evesham, an area of intense irrigated production located within the Environment Agency’s Warwickshire Avon CAMS Catchment. The research was based on a combination of methodologies including desk-based review of published and grey literature, computer agroclimatic and water balance modelling, GIS mapping, meetings with key informants and a stakeholder workshop. Future climate datasets were derived from the latest UK Climate Impacts Programme (UKICIP02) climatology, using selected emission scenarios for the 2020s, 2050s and 2080s. These scenarios were then used to model and map the future agroclimatic conditions under which agriculture might operate and the consequent impacts on irrigation need (depths of water applied) and volumetric demand. This was complimented by a postal survey to abstractors and a stakeholder workshop, to identify, review and assess farmer adaptation options and responses. The key findings arising from the research, implications for water resource management and recommendations for further work are summarised below. Using a geographical information system (GIS), a series of agroclimate maps have been produced, for the baseline and selected UKCIP02 scenario. The maps show major changes in agroclimate within the catchment over the next 50 years. The driest agroclimate zones are currently located around Worcester, Evesham, Tewkesbury and Gloucester, corresponding to areas where horticultural production and irrigation demand are most concentrated. By the 2020s, all agroclimate zones are predicted to increase in aridity. By the 2050s the entire catchment is predicted to have a drier agroclimate than is currently experienced anywhere in the driest parts of the catchment. This will have major impacts on the pattern of land use and irrigation water demand. Cont/d

A generalized bayesian inference method for constraining the interiors of super Earths and sub-Neptunes

We aim to present a generalized Bayesian inference method for constraining interiors of super Earths and sub-Neptunes. Our methodology succeeds in quantifying the degeneracy and correlation of structural parameters for high dimensional parameter spaces. Specifically, we identify what constraints can be placed on composition and thickness of core, mantle, ice, ocean, and atmospheric layers given observations of mass, radius, and bulk refractory abundance constraints (Fe, Mg, Si) from observations of the host star's photospheric composition. We employed a full probabilistic Bayesian inference analysis that formally accounts for observational and model uncertainties. Using a Markov chain Monte Carlo technique, we computed joint and marginal posterior probability distributions for all structural parameters of interest. We included state-of-the-art structural models based on self-consistent thermodynamics of core, mantle, high-pressure ice, and liquid water. Furthermore, we tested and compared two different atmospheric models that are tailored for modeling thick and thin atmospheres, respectively. First, we validate our method against Neptune. Second, we apply it to synthetic exoplanets of fixed mass and determine the effect on interior structure and composition when (1) radius, (2) atmospheric model, (3) data uncertainties, (4) semi-major axes, (5) atmospheric composition (i.e., a priori assumption of enriched envelopes versus pure H/He envelopes), and (6) prior distributions are varied. Our main conclusions are: [...]Comment: Astronomy & Astrophysics, 597, A37, 17 pages, 11 figure

Optical phase synchronization in coherent optical beamformers for phased array receive antennas

An optical phase synchronization system using a power feedback loop technique is experimentally demonstrated. The system allows coherent combining of signals modulated on the same optical carrier in a hybrid optical beam forming system setup

The power of implicit social relation in rating prediction of social recommender systems of social recommender

The explosive growth of social networks in recent times has presented a powerful source of information to be utilized as an extra source for assisting in the social recommendation problems. The social recommendation methods that are based on probabilistic matrix factorization improved the recommendation accuracy and partly solved the cold-start and data sparsity problems. However, these methods only exploited the explicit social relations and almost completely ignored the implicit social relations. In this article, we firstly propose an algorithm to extract the implicit relation in the undirected graphs of social networks by exploiting the link prediction techniques. Furthermore, we propose a new probabilistic matrix factorization method to alleviate the data sparsity problem through incorporating explicit friendship and implicit friendship. We evaluate our proposed approach on two real datasets, Last.Fm and Douban. The experimental results show that our method performs much better than the state-of-the-art approaches, which indicates the importance of incorporating implicit social relations in the recommendation process to address the poor prediction accuracy