Showing papers by "University of Sussex published in 2010"

Review of Particle Physics

Abstract: This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on neutrino mass, mixing, and oscillations, QCD, top quark, CKM quark-mixing matrix, V-ud & V-us, V-cb & V-ub, fragmentation functions, particle detectors for accelerator and non-accelerator physics, magnetic monopoles, cosmological parameters, and big bang cosmology.

The Herschel-SPIRE instrument and its in-flight performance

Abstract: The Spectral and Photometric Imaging REceiver (SPIRE), is the Herschel Space Observatory`s submillimetre camera and spectrometer It contains a three-band imaging photometer operating at 250, 350 and 500 mu m, and an imaging Fourier-transform spectrometer (FTS) which covers simultaneously its whole operating range of 194-671 mu m (447-1550 GHz) The SPIRE detectors are arrays of feedhorn-coupled bolometers cooled to 03 K The photometer has a field of view of 4' x 8', observed simultaneously in the three spectral bands Its main operating mode is scan-mapping, whereby the field of view is scanned across the sky to achieve full spatial sampling and to cover large areas if desired The spectrometer has an approximately circular field of view with a diameter of 26' The spectral resolution can be adjusted between 12 and 25 GHz by changing the stroke length of the FTS scan mirror Its main operating mode involves a fixed telescope pointing with multiple scans of the FTS mirror to acquire spectral data For extended source measurements, multiple position offsets are implemented by means of an internal beam steering mirror to achieve the desired spatial sampling and by rastering of the telescope pointing to map areas larger than the field of view The SPIRE instrument consists of a cold focal plane unit located inside the Herschel cryostat and warm electronics units, located on the spacecraft Service Module, for instrument control and data handling Science data are transmitted to Earth with no on-board data compression, and processed by automatic pipelines to produce calibrated science products The in-flight performance of the instrument matches or exceeds predictions based on pre-launch testing and modelling: the photometer sensitivity is comparable to or slightly better than estimated pre-launch, and the spectrometer sensitivity is also better by a factor of 15-2

Baryon Acoustic Oscillations in the Sloan Digital Sky Survey Data Release 7 Galaxy Sample

Abstract: The spectroscopic Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) galaxy sample represents the final set of galaxies observed using the original SDSS target selection criteria. We analyse the clustering of galaxies within this sample, including both the luminous red galaxy and main samples, and also include the 2-degree Field Galaxy Redshift Survey data. In total, this sample comprises 893 319 galaxies over 9100 deg(2). Baryon acoustic oscillations (BAO) are observed in power spectra measured for different slices in redshift; this allows us to constrain the distance-redshift relation at multiple epochs. We achieve a distance measure at redshift z = 0.275, of r(s)(z(d))/D-V(0.275) = 0.1390 +/- 0.0037 (2.7 per cent accuracy), where r(s)(z(d)) is the comoving sound horizon at the baryon-drag epoch, D-V(z) equivalent to [(1 + z)(2)D(A)(2)cz/H(z)](1/3), D-A(z) is the angular diameter distance and H(z) is the Hubble parameter. We find an almost independent constraint on the ratio of distances D-V(0.35)/D-V(0.2) = 1.736 +/- 0.065, which is consistent at the 1.1 sigma level with the best-fitting Lambda cold dark matter model obtained when combining our z = 0.275 distance constraint with the Wilkinson Microwave Anisotropy Probe 5-year (WMAP5) data. The offset is similar to that found in previous analyses of the SDSS DR5 sample, but the discrepancy is now of lower significance, a change caused by a revised error analysis and a change in the methodology adopted, as well as the addition of more data. Using WMAP5 constraints on Omega(b)h(2) and Omega(c) h(2), and combining our BAO distance measurements with those from the Union supernova sample, places a tight constraint on Omega(m) = 0.286 +/- 0.018 and H-0 = 68.2 +/- 2.2 km s(-1) Mpc(-1) that is robust to allowing Omega(k) not equal 0 and omega not equal -1. This result is independent of the behaviour of dark energy at redshifts greater than those probed by the BAO and supernova measurements. Combining these data sets with the full WMAP5 likelihood constraints provides tight constraints on both Omega(k) = -0.006 +/- 0.008 and omega = -0.97 +/- 0.10 for a constant dark energy equation of state.

Research methods in business studies

Abstract: This accessible guide provides clear, practical explanations of key research methods in business studies, presenting a step-by-step approach to data collection, analysis and problem solving. Readers will learn how to formulate a research question, choose an appropriate research method, argue and motivate, collect and analyse data, and present findings in a logical and convincing manner. The authors evaluate various qualitative and quantitative methods and their consequences, guiding readers to the most appropriate research design for particular questions. Furthermore, the authors provide instructions on how to write reports and dissertations in a clearly structured and concise style. Now in its fifth edition, this popular textbook includes new and dedicated chapters on data collection for qualitative research, qualitative data analysis, data collection for quantitative research, multiple regression, and additional methods of quantitative analysis. Cases and examples have been updated throughout, increasing the applicability of these research methods across various situations.

Honey bee colony losses

Abstract: Apis mellifera, colony losses. honey bee, Varroa destructor Journal of Apicultural Research 49(1): 1-6 (2010) © IBRA 2010 DOI 10.3896/IBRA.1.49.1.01 Apiculture has been in decline in both Europe and the USA over recent decades, as is shown by the decreasing numbers of managed honey bee (Apis mellifera L.) colonies (Ellis et al., 2010; Potts et al., 2010). It therefore is crucial to make beekeeping a more attractive hobby and a less laborious profession, in order to encourage local apiculture and pollination. Apart from socio-economic factors, which can only be addressed by politicians, sudden losses of honey bee colonies have occurred, and have received considerable public attention. Indeed, in the last few years, the world’s press has been full of eye catching but often uninformative headlines proclaiming the dramatic demise of the honey bee, a world pollinator crisis and the spectre of mass human starvation. “Colony Collapse Disorder” (CCD) in the USA has attracted great attention, and scientists there and in Europe are working hard to provide explanations for these extensive colony losses. Colony losses have also occurred elsewhere (Figs 1 and 2), but examination of the historical record shows that such extensive losses are not unusual (vanEngelsdorp and Meixner, 2009). Almost exactly a century ago, in 1906, beekeepers on the Isle of Wight, a small island off the south coast of England, noticed that many of their honey bee colonies were dying, with numerous bees crawling from the hive, unable to fly. Despite some sceptical beekeepers suggesting that this was “paralysis”, a condition which had long been known, the colony losses were widely reported in the media, and beekeepers became convinced that the cause was a novel

How to do a meta-analysis.

Abstract: Meta-analysis is a statistical tool for estimating the mean and variance of underlying population effects from a collection of empirical studies addressing ostensibly the same research question. Meta-analysis has become an increasing popular and valuable tool in psychological research, and major review articles typically employ these methods. This article describes the process of conducting meta-analysis: selecting articles, developing inclusion criteria, calculating effect sizes, conducting the actual analysis (including information on how to do the analysis on popular computer packages such as IBM SPSS and R) and estimating the effects of publication bias. Guidance is also given on how to write up a meta-analysis.

Observation of a centrality-dependent dijet asymmetry in lead-lead collisions at √sNN=2.76 Tev with the ATLAS detector at the LHC

Abstract: By using the ATLAS detector, observations have been made of a centrality-dependent dijet asymmetry in the collisions of lead ions at the Large Hadron Collider. In a sample of lead-lead events with a per-nucleon center of mass energy of 2.76 TeV, selected with a minimum bias trigger, jets are reconstructed in fine-grained, longitudinally segmented electromagnetic and hadronic calorimeters. The transverse energies of dijets in opposite hemispheres are observed to become systematically more unbalanced with increasing event centrality leading to a large number of events which contain highly asymmetric dijets. This is the first observation of an enhancement of events with such large dijet asymmetries, not observed in proton-proton collisions, which may point to an interpretation in terms of strong jet energy loss in a hot, dense medium.

Evolution of halophytes: multiple origins of salt tolerance in land plants

Abstract: The evolution of salt tolerance is interesting for several reasons. First, since salt-tolerant plants (halophytes) employ several different mechanisms to deal with salt, the evolution of salt tolerance represents a fascinating case study in the evolution of a complex trait. Second, the diversity of mechanisms employed by halophytes, based on processes common to all plants, sheds light on the way that a plant’s physiology can become adapted to deal with extreme conditions. Third, as the amount of salt-affected land increases around the globe, understanding the origins of the diversity of halophytes should provide a basis for the use of novel species in bioremediation and conservation. In this review we pose the question, how many times has salt tolerance evolved since the emergence of the land plants some 450–470 million years ago? We summarise the physiological mechanisms underlying salt-tolerance and provide an overview of the number and diversity of salt-tolerant terrestrial angiosperms (defined as plants that survive to complete their life cycle in at least 200 mM salt). We consider the evolution of halophytes using information from fossils and phylogenies. Finally, we discuss the potential for halophytes to contribute to agriculture and land management and ask why, when there are naturally occurring halophytes, it is proving to be difficult to breed salt-tolerant crops.

Exploring the sequence determinants of amyloid structure using position-specific scoring matrices

Abstract: Protein aggregation results in beta-sheet-like assemblies that adopt either a variety of amorphous morphologies or ordered amyloid-like structures. These differences in structure also reflect biological differences; amyloid and amorphous beta-sheet aggregates have different chaperone affinities, accumulate in different cellular locations and are degraded by different mechanisms. Further, amyloid function depends entirely on a high intrinsic degree of order. Here we experimentally explored the sequence space of amyloid hexapeptides and used the derived data to build Waltz, a web-based tool that uses a position-specific scoring matrix to determine amyloid-forming sequences. Waltz allows users to identify and better distinguish between amyloid sequences and amorphous beta-sheet aggregates and allowed us to identify amyloid-forming regions in functional amyloids.

Keep it complex.

Abstract: When knowledge is uncertain, experts should avoid pressures to simplify their advice. Render decision-makers accountable for decisions, says Andy Stirling.

Diversity and network coherence as indicators of interdisciplinarity: case studies in bionanoscience

Abstract: The multidimensional character and inherent conflict with categorisation of interdisciplinarity makes its mapping and evaluation a challenging task. We propose a conceptual framework that aims to capture interdisciplinarity in the wider sense of knowledge integration, by exploring the concepts of diversity and coherence. Disciplinary diversity indicators are developed to describe the heterogeneity of a bibliometric set viewed from predefined categories, i.e. using a top-down approach that locates the set on the global map of science. Network coherence indicators are constructed to measure the intensity of similarity relations within a bibliometric set, i.e. using a bottom-up approach, which reveals the structural consistency of the publications network. We carry out case studies on individual articles in bionanoscience to illustrate how these two perspectives identify different aspects of interdisciplinarity: disciplinary diversity indicates the large-scale breadth of the knowledge base of a publication; network coherence reflects the novelty of its knowledge integration. We suggest that the combination of these two approaches may be useful for comparative studies of emergent scientific and technological fields, where new and controversial categorisations are accompanied by equally contested claims of novelty and interdisciplinarity.

Mapping knowledge structure by keyword co-occurrence: a first look at journal papers in Technology Foresight

Abstract: This study proposes an approach for visualizing a knowledge structure, the proposed approach creates a three-dimensional “Research focused parallelship network”, a “Keyword Co-occurrence Network”, and a two-dimensional knowledge map to facilitate visualization of the knowledge structure created by journal papers from different perspectives. The networks and knowledge maps can be depicted differently by choosing different information as the network actor, e.g. author, institute or country keyword, to reflect knowledge structures in micro-, meso-, and macro-levels, respectively. Technology Foresight is selected as an example to illustrate the method proposed in this study. A total of 556 author keywords contained in 181 Technology Foresight related papers have been analyzed. European countries, China, India and Brazil are located at the core of Technology Foresight research. Quantitative ways of mapping journal papers are investigated in this study to unveil emerging elements as well as to demonstrate dynamics and visualization of knowledge. The quantitative method provided in this paper shows a possible way of visualizing and evaluating knowledge structure; thus a computerized calculation is possible for potential quantitative applications, e.g. R&D resource allocation, research performance evaluation, science map, etc.

The IMAGEN study: reinforcement-related behaviour in normal brain function and psychopathology.

Abstract: The IMAGEN study: reinforcement-related behaviour in normal brain function and psychopathology

The top 100 questions of importance to the future of global agriculture

Abstract: Despite a significant growth in food production over the past half-century, one of the most important challenges facing society today is how to feed an expected population of some nine billion by the middle of the 20th century. To meet the expected demand for food without significant increases in prices, it has been estimated that we need to produce 70-100 per cent more food, in light of the growing impacts of climate change, concerns over energy security, regional dietary shifts and the Millennium Development target of halving world poverty and hunger by 2015. The goal for the agricultural sector is no longer simply to maximize productivity, but to optimize across a far more complex landscape of production, rural development, environmental, social justice and food consumption outcomes. However, there remain significant challenges to developing national and international policies that support the wide emergence of more sustainable forms of land use and efficient agricultural production. The lack of information flow between scientists, practitioners and policy makers is known to exacerbate the difficulties, despite increased emphasis upon evidence-based policy. In this paper, we seek to improve dialogue and understanding between agricultural research and policy by identifying the 100 most important questions for global agriculture. These have been compiled using a horizon-scanning approach with leading experts and representatives of major agricultural organizations worldwide. The aim is to use sound scientific evidence to inform decision making and guide policy makers in the future direction of agricultural research priorities and policy support. If addressed, we anticipate that these questions will have a significant impact on global agricultural practices worldwide, while improving the synergy between agricultural policy, practice and research. This research forms part of the UK Government's Foresight Global Food and Farming Futures project.

If You Can't Beat Them, Join Them? Explaining Social Democratic Responses to the Challenge from the Populist Radical Right in Western Europe

Abstract: Over the last three decades many Western European social democratic parties have been challenged by populist radical right parties. The growth and success of parties on the right flank of the party system represents a triple challenge to the social democrats: they increase the salience of issues traditionally ‘owned’ by the right; they appeal to working-class voters who traditionally support the centre left; and they may facilitate the formation of centre-right governments. This article explores social democratic parties' strategic options in the face of this challenge, and tests the widespread assumption that the centre-left parties respond by taking a tougher stance on issues related to immigration and integration. Comparative analysis of developments in Austria, Denmark, the Netherlands and Norway reveals significant variation in the substance, scope and pace of the strategic responses of their social democratic parties. And it suggests that those responses are influenced not only by the far right but also by the reactions of mainstream centre-right parties and by parties on their left (and liberal) flank. Internal disunity, potential or actual, is also an important factor.

Effects of prosocial video games on prosocial behavior

Abstract: Previous research has documented that playing violent video games has various negative effects on social behavior in that it causes an increase in aggressive behavior and a decrease in prosocial behavior. In contrast, there has been much less evidence on the effects of prosocial video games. In the present research, 4 experiments examined the hypothesis that playing a prosocial (relative to a neutral) video game increases helping behavior. In fact, participants who had played a prosocial video game were more likely to help after a mishap, were more willing (and devoted more time) to assist in further experiments, and intervened more often in a harassment situation. Results further showed that exposure to prosocial video games activated the accessibility of prosocial thoughts, which in turn promoted prosocial behavior. Thus, depending on the content of the video game, playing video games not only has negative effects on social behavior but has positive effects as well.

‘Mind the Gap!’ Integrating Approaches to Internal and International Migration

Abstract: The interdisciplinary field of migration studies is split into internal and international migration, characterised by different literatures, concepts, methods and policy agendas. Most migration scholars nowadays research international migration, even though, quantitatively, internal migration is more important. Yet the distinction between internal and international moves becomes increasingly blurred, not only because of geopolitical events and the changing nature and configuration of borders, but also because migrants' journeys are becoming increasingly multiple, complex and fragmented. We present a schematic model that sets out 10 migration pathways that combine internal and international migration, and return migration, in various sequenced relationships. We survey the limited literature that attempts to compare and integrate internal and international migration within the same theoretical framework, both general models and some case-study literature from Mexico. We consider three approaches where theoretical transfer seems to hold potential: systems approaches, migrant integration, and the migration-development nexus. We conclude that considerable potential exists for integrating the study of internal and international migration, at both the theoretical and the empirical level. Too often one is studied without reference to the other, yielding a partial analysis. However, we baulk at attempting any 'grand theory' of migration which incorporates all types of migration, in all places and at all times.

Evidence of selection upon genomic GC-content in bacteria

Abstract: The genomic GC-content of bacteria varies dramatically, from less than 20% to more than 70%. This variation is generally ascribed to differences in the pattern of mutation between bacteria. Here we test this hypothesis by examining patterns of synonymous polymorphism using datasets from 149 bacterial species. We find a large excess of synonymous GC→AT mutations over AT→GC mutations segregating in all but the most AT-rich bacteria, across a broad range of phylogenetically diverse species. We show that the excess of GC→AT mutations is inconsistent with mutation bias, since it would imply that most GC-rich bacteria are declining in GC-content; such a pattern would be unsustainable. We also show that the patterns are probably not due to translational selection or biased gene conversion, because optimal codons tend to be AT-rich, and the excess of GC→AT SNPs is observed in datasets with no evidence of recombination. We therefore conclude that there is selection to increase synonymous GC-content in many species. Since synonymous GC-content is highly correlated to genomic GC-content, we further conclude that there is selection on genomic base composition in many bacteria.

HerMES: The SPIRE confusion limit

Abstract: We report on the sensitivity of SPIRE photometers on the Herschel Space Observatory. Specifically, we measure the confusion noise from observations taken during the science demonstration phase of the Herschel Multi-tiered Extragalactic Survey. Confusion noise is defined to be the spatial variation of the sky intensity in the limit of infinite integration time, and is found to be consistent among the different fields in our survey at the level of 5.8, 6.3 and 6.8 mJy/beam at 250, 350 and 500 μm, respectively. These results, together with the measured instrument noise, may be used to estimate the integration time required for confusion limited maps, and provide a noise estimate for maps obtained by SPIRE.

Science overlay maps: A new tool for research policy and library management

Abstract: We present a novel approach to visually locate bodies of research within the sciences, both at each moment of time and dynamically. This article describes how this approach fits with other efforts to locally and globally map scientific outputs. We then show how these science overlay maps help benchmarking, explore collaborations, and track temporal changes, using examples of universities, corporations, funding agencies, and research topics. We address their conditions of application and discuss advantages, downsides, and limitations. Overlay maps especially help investigate the increasing number of scientific developments and organizations that do not fit within traditional disciplinary categories. We make these tools available online to enable researchers to explore the ongoing sociocognitive transformations of science and technology systems. © 2010 Wiley Periodicals, Inc.

Using Principal Components and Factor Analysis in Animal Behaviour Research: Caveats and Guidelines

Abstract: Principal component (PCA) and factor analysis (FA) are widely used in animal behaviour research. However, many authors automatically follow questionable practices implemented by default in general-purpose statistical software. Worse still, the results of such analyses in research reports typically omit many crucial details which may hamper their evaluation. This article provides simple non-technical guidelines for PCA and FA. A standard for reporting the results of these analyses is suggested. Studies using PCA and FA must report: (1) whether the correlation or covariance matrix was used; (2) sample size, preferably as a footnote to the table of factor loadings; (3) indices of sampling adequacy; (4) how the number of factors was assessed; (5) communalities when sample size is small; (6) details of factor rotation; (7) if factor scores are computed, present determinacy indices; (8) preferably they should publish the original correlation matrix.

53BP1-dependent robust localized KAP-1 phosphorylation is essential for heterochromatic DNA double-strand break repair

Abstract: DNA double-strand breaks (DSBs) trigger ATM (ataxia telangiectasia mutated) signalling and elicit genomic rearrangements and chromosomal fragmentation if misrepaired or unrepaired. Although most DSB repair is ATM-independent, ~15% of ionizing radiation (IR)-induced breaks persist in the absence of ATM-signalling1. 53BP1 (p53-binding protein 1) facilitates ATM-dependent DSB repair but is largely dispensable for ATM activation or checkpoint arrest. ATM promotes DSB repair within heterochromatin by phosphorylating KAP-1 (KRAB-associated protein 1, also known as TIF1β, TRIM28 or KRIP-1; ref. 2). Here, we show that the ATM signalling mediator proteins MDC1, RNF8, RNF168 and 53BP1 are also required for heterochromatic DSB repair. Although KAP-1 phosphorylation is critical for 53BP1-mediated repair, overall phosphorylated KAP-1 (pKAP-1) levels are only modestly affected by 53BP1 loss. pKAP-1 is transiently pan-nuclear but also forms foci overlapping with γH2AX in heterochromatin. Cells that do not form 53BP1 foci, including human RIDDLE (radiosensitivity, immunodeficiency, dysmorphic features and learning difficulties) syndrome cells, fail to form pKAP-1 foci. 53BP1 amplifies Mre11–NBS1 accumulation at late-repairing DSBs, concentrating active ATM and leading to robust, localized pKAP-1. We propose that ionizing-radiation induced foci (IRIF) spatially concentrate ATM activity to promote localized alterations in regions of chromatin otherwise inhibitory to repair.