Inelastic J/ψJ/\psi production in polarized photon-hadron collisions

Presented here is a calculation of inelastic $J/\psi$ production in polarized photon-hadron collisions under the framework of NRQCD factorization formalism. We consider the photoproduction of \jpsi in the energy range relevant to HERA. The Weizs\"acker-Williams approximation is adopted in the evaluation of the cross sections for $ep$ collisions. We found that this process can give another independent test for the color-octet mechanism, and the different features for the two color-octet processes may provide further informations on the mechanism for inelastic \jpsi photoproduction. And the discrepancy on the production asymmetry $A$ between various sets of polarized gluon distribution functions is also found to be distinctive.Comment: 14pages, 6 PS figure

Lattice Calculation of the Strangeness Magnetic Moment of the Nucleon

We report on a lattice QCD calculation of the strangeness magnetic moment of the nucleon. Our result is $G_M^s(0) = - 0.36 \pm 0.20$. The sea contributions from the u and d quarks are about 80% larger. However, they cancel to a large extent due to their electric charges, resulting in a smaller net sea contribution of $- 0.097 \pm 0.037 \mu_N$ to the nucleon magnetic moment. As far as the neutron to proton magnetic moment ratio is concerned, this sea contribution tends to cancel out the cloud-quark effect from the Z-graphs and result in a ratio of $-0.68 \pm 0.04$ which is close to the SU(6) relation and the experiment. The strangeness Sachs electric mean-square radius $_E$ is found to be small and negative and the total sea contributes substantially to the neutron electric form factor.Comment: 10 pages, 5 figures, LaTex, UK/97-23, ADP-97-55/T28

Finding benchmark brown dwarfs to probe the IMF as a function of time

Using a simulated disk brown dwarf (BD) population, we find that new large area infrared surveys are expected to identify enough BDs covering wide enough mass--age ranges to potentially measure the mass function down to ~0.03Mo, and the BD formation history out to 10 Gyr, at a level capable of establishing if BD formation follows star formation. We suggest these capabilities are best realised by spectroscopic calibration of BD properties (Teff, g and [M/H]) which, when combined with a measured luminosity and an evolutionary model can give BD mass and age relatively independent of BD atmosphere models. Such calibration requires an empirical understanding of how BD spectra are affected by variations in these properties, and thus the identification and study of "benchmark BDs" whose age and composition can be established independently. We identify the best sources of benchmark BDs as young open cluster members, moving group members, and wide (>1000AU) BD companions to both subgiant stars and high mass white dwarfs (WDs). We have used 2MASS to measure a wide L dwarf companion fraction of 2.7(+0.7/-0.5)%, which equates to a BD companion fraction of 34(+9/-6)% for an alpha~1 companion mass function. Using this value we simulate populations of wide BD binaries, and estimate that 80(+21/-14) subgiant--BD binaries, and 50(+13/-10) benchmark WD--BD binaries could be identified using current and new facilities. The WD--BD binaries should all be identifiable using the Large Area Survey component of UKIDSS combined with Sloan. Discovery of the subgiant--BD binaries will require a NIR imaging campaign around a large (~900) sample of Hipparcos subgiants. If identified, spectral studies of these benchmark brown dwarfs could reveal the spectral sensitivities across the Teff, g and [M/H] space probed by new surveys.Comment: 18 pages, 12 figures, accepted for publication in MNRA

Compact stellar systems and cluster environments

We have extended the search for luminous (M_{b_J} <= -10.5) compact stellar systems (CSSs) in the Virgo and Fornax galaxy clusters by targeting with the recently commissioned AAOmega spectrograph three cluster environments -- the cluster cores around M87 and NGC 1399, intracluster space, and a major galaxy merger site (NGC 1316). We have significantly increased the number of redshift-confirmed CSSs in the Virgo cluster core and located three Virgo intracluster globular clusters (IGCs) at a large distance from M87 (154-173 arcmin or ~750-850 kpc) -- the first isolated IGCs to be redshift-confirmed. We estimate luminous CSS populations in each cluster environment, and compare their kinematic and photometric properties. We find that (1) the estimated luminous CSS population in the Virgo cluster core is half of that in Fornax, possibly reflecting the more relaxed dynamical status of the latter; (2) in both clusters the luminous CSS velocity dispersions are less than those of the cD galaxy GC system or cluster dE galaxies, suggesting luminous CSSs have less energetic orbits; (3) Fornax has a sub-population of cluster core luminous CSSs that are redder and presumably more metal-rich than those found in Virgo; (4) no luminous CSSs were found in a 10-20 arcmin (60-130 kpc) radial arc east of the 3 Gyr old NGC 1316 galaxy merger remnant or in the adjacent intracluster region, implying that any luminous CSSs created in the galaxy merger have not been widely dispersed.Comment: 20 pages, 15 figures, 8 table

Social validity of randomised controlled trials in health services research and intellectual disabilities: a qualitative exploration of stakeholder views

<p>Abstract</p> <p>Background</p> <p>Randomised controlled trials (RCTs) are the gold standard of evidence-based practice in medicine but they have had limited influence in the field of intellectual disabilities. Previous literature suggests that participants and professionals have limited tolerance for this type of research methodology. However, it is not known how well service users, carers and other health professionals understand and accept the need for RCTs, and why it is important for individuals with intellectual disabilities to be included in this kind of research.</p> <p>Methods</p> <p>We examined individual perceptions of RCTs in 51 participants (18 carers, 6 service users and 27 professionals) using semi-structured interviews. A framework approach was adopted in the analysis of data.</p> <p>Results</p> <p>We found that participants had concerns about capacity and resource allocation but held positive views towards this type of research methodology. Understanding of the principles behind RCTs was poor amongst service users and a minority of carers, but mediated by previous exposure to research for professionals.</p> <p>Conclusions</p> <p>The social validity of RCTs in intellectual disabilities may be compromised by lack of understanding of the design and the on-going concerns about obtaining informed consent especially in incapacitated adults. However, the overall finding that the need for this form of research was seen in a positive light suggests that there is a turning point in the perceptions of stakeholders working in intellectual disabilities services. We recommend that researchers include on-going education on RCT design during trials, tailoring it to all stakeholders with emphasis on strong service user and care involvement. This could be a pivotal element in improving acceptability of, and recruitment to RCTs.</p

Microgeographical, inter-individual, and intra-individual variation in the flower characters of Iberian pear Pyrus bourgaeana (Rosaceae)

Flower characteristics have been traditionally considered relatively constant within species. However, there are an increasing number of examples of variation in flower characteristics. In this study, we examined the variation in attracting and rewarding flower characters at several ecological levels in a metapopulation of Pyrus bourgaeana in the Doñana area (SW Spain). We answered the following questions: what are the variances of morphological and nectar characters of flowers? How important are intra-individual and inter-individual variance in flower characters? Are there microgeographical differences in flower characters? And if so, are they consistent between years? In 2008 and 2009, we sampled flowers of 72 trees from five localities. For six flower morphological and two nectar characteristics, we calculated coefficients of variation (CV). The partitioning of total variation among-localities, among-individuals, and within-individuals was estimated. To analyze differences among localities and their consistency between years, we conducted generalized linear mixed models. The CVs of nectar characters were always higher than those of morphological characters. As expected, inter-individual variation was the main source of variation of flower morphology, but nectar characters had significant variation at both intra- and inter-individual levels. For most floral traits, there were no differences among localities. Our study documents that variation is a scale-dependent phenomenon and that it is essential to consider intra- and inter-individual variance when investigating the causes and consequences of variation. It also shows that single year studies of floral characters should be viewed with caution

The Globular Cluster Systems of Abell 1185

We examine the properties of a previously discovered population of globular clusters in the heart of the rich galaxy cluster Abell 1185 that might be intergalactic in nature. Deep images obtained with the Advanced Camera for Surveys (ACS) aboard Hubble Space Telescope (HST) confirm the presence of ~ 1300 globular clusters brighter than I_{F814W} = 27.3 mag in a field devoid of any large galaxies. The luminosities and colors of these objects are found to be similar to those of metal-poor globular clusters observed in many galaxies to date. Although a significant fraction of the detected globular clusters undoubtedly reside in the outer halos of galaxies adjacent to this field, detailed modeling of their distribution suggests that the majority of these objects are likely to be intergalactic, in the sense that they are not gravitationally bound to any individual galaxy. We conclude that the true nature and origin of the globular cluster population in the core of A1185 -- galactic residents or intergalactic wanderers -- remains uncertain, and suggest how future observation could resolve this ambiguity.Comment: Accepted for publication in Astronomy and Astrophysics, 13 pages, 15 figure

TRY plant trait database - enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Co expression of SCF and KIT in gastrointestinal stromal tumours (GISTs) suggests an autocrine/paracrine mechanism

KIT is a tyrosine kinase receptor expressed by several tumours, which has for specific ligand the stem cell factor (SCF). KIT is the main oncogene in gastrointestinal stromal tumours (GISTs), and gain-of-function KIT mutations are present in 70% of these tumours. The aim of the study was to measure and investigate the mechanisms of KIT activation in 80 KIT-positive GIST patients. KIT activation was quantified by detecting phosphotyrosine residues in Western blotting. SCF production was determined by reverse transcriptase–PCR, ELISA and/or immunohistochemistry. Primary cultures established from three GISTs were also analysed. The results show that KIT activation was detected in all cases, even in absence of KIT mutations. The fraction of activated KIT was not correlated with the mutational status of GISTs. Membrane and soluble isoforms of SCF mRNA were present in all GISTs analysed. Additionally, SCF was also detected in up to 93% of GISTs, and seen to be present within GIST cells. Likewise, the two SCF mRNA isoforms were found to be expressed in GIST-derived primary cultures. Thus, KIT activation in GISTs may in part result from the presence of SCF within the tumours