Spatial distribution and galactic model parameters of cataclysmic variables

The spatial distribution, galactic model parameters and luminosity function of cataclysmic variables (CVs) in the solar neighbourhood have been determined from a carefully established sample of 459 CVs. The sample contains all of the CVs with distances computed from the Period-Luminosity-Colours (PLCs) relation of CVs which has been recently derived and calibrated with {\em 2MASS} photometric data. It has been found that an exponential function fits best to the observational z-distributions of all of the CVs in the sample, non-magnetic CVs and dwarf novae, while the sech^{2} function is more appropriate for nova-like stars and polars. The vertical scaleheight of CVs is 158$\pm$14 pc for the {\em 2MASS} J-band limiting apparent magnitude of 15.8. On the other hand, the vertical scaleheights are 128$\pm$20 and 160$\pm$5 pc for dwarf novae and nova-like stars, respectively. The local space density of CVs is found to be $\sim3\times10^{-5}$ pc^{-3} which is in agreement with the lower limit of the theoretical predictions. The luminosity function of CVs shows an increasing trend toward higher space densities at low luminosities, implying that the number of short-period systems should be high. The discrepancies between the theoretical and observational population studies of CVs will almost disappear if for the z-dependence of the space density the sech^{2} density function is used.Comment: 29 pages, 9 figures and 5 tables, accepted for publication in New Astronom

Noise resistant generalized parametric validity index of clustering for gene expression data

This article has been made available through the Brunel Open Access Publishing Fund.Validity indices have been investigated for decades. However, since there is no study of noise-resistance performance of these indices in the literature, there is no guideline for determining the best clustering in noisy data sets, especially microarray data sets. In this paper, we propose a generalized parametric validity (GPV) index which employs two tunable parameters α and β to control the proportions of objects being considered to calculate the dissimilarities. The greatest advantage of the proposed GPV index is its noise-resistance ability, which results from the flexibility of tuning the parameters. Several rules are set to guide the selection of parameter values. To illustrate the noise-resistance performance of the proposed index, we evaluate the GPV index for assessing five clustering algorithms in two gene expression data simulation models with different noise levels and compare the ability of determining the number of clusters with eight existing indices. We also test the GPV in three groups of real gene expression data sets. The experimental results suggest that the proposed GPV index has superior noise-resistance ability and provides fairly accurate judgements

Non-Hodgkin’s Lymphoma of the Uterine Cervix

Non Hodgkin’s Lymphoma (NHL) causes many deaths worldwide and its incidence is increasing. They occur commonly in middle aged and elderly people and are disseminated at diagnosis. We present an interesting case of NHL in a 52 years old female, who presented with past a history of postmenopausal bleeding. A 3 x 5 cms endocervical polyp was noticed in the cervix. Biopsy of the polyp revealed it to be a CD20-positive diffuse large B-cell (DLBCL)-type NHL. She was diagnosed as stage IE after staging work-up. She attained a complete response, and has been in remission for 1 year 8 months

Report on the first phase of the study on men’s usage of the Bradford Health of Men services

This is a summary of the full report on the first year of the HOM project in Bradford, published in March 2005 and available at www.healthofmen.com . In this summary there is a concentration on three things, the background to the project, the experiences of the HOM team in setting up and managing projects and the views of the men involved in the projects. The summary is mostly a list of the things that the team found to be important in setting up projects and, equally important, some of the things not to do. There is, of course, a much fuller discussion of the details of projects, supporting data and the theoretical model of how men and health workers interact to manage health

12CaO.7Al2O3 ceramic: A review of the electronic and optoelectronic applications in display devices

The alumina-based compound, 12CaO.7Al2O3, is a ceramic material with a unique cage-like lattice. Such a structure has enabled scientists to extract various new characteristics from this compound, most of which were unknown until quite recently. This compound has the ability to incorporate different anionic species and even electrons to the empty space inside its cages, thereby changing from an insulator into a conductive oxide. The cage walls can also incorporate different rare earth phosphor elements producing an oxide-based phosphor. All these characteristics are obtained without a significant change in the structure of the lattice. It is, therefore, reasonable to expect that this compound will receive attention as a potential material for display applications. This review article presents recent investigations into the application of 12CaO.7Al2O3 ceramic in various display devices, the challenges, opportunities and possible areas of future investigation into the development of this naturally abundant and environmental friendly material in the field of display.LP Displays Ltd, Blackburn, UK for partial funding of the studentship at Queen Mary, University of London. Dr Lesley Hanna of Wolfson Centre for Materials Processing, Brunel University Londo

Characterisation of Flame Development with Hydrous and Anhydrous Ethanol Fuels in a Spark-Ignition Engine with Direct Injection and Port Injection Systems

This paper presents a study of the combustion mechanism of hydrous and anhydrous ethanol in comparison to iso-octane and gasoline fuels in a single-cylinder spark-ignition research engine operated at 1000 rpm with 0.5 bar intake plenum pressure. The engine was equipped with optical access and tests were conducted with both Port Fuel Injection (PFI) and Direct Injection (DI) mixture preparation methods; all tests were conducted at stoichiometric conditions. The results showed that all alcohol fuels, both hydrous and anhydrous, burned faster than iso-octane and gasoline for both PFI and DI operation. The rate of combustion and peak cylinder pressure decreased with water content in ethanol for both modes of mixture preparation. Flame growth data were obtained by high-speed chemiluminescence imaging. These showed similar trends to the mass fraction burned curves obtained by in-cylinder heat release analysis for PFI operation; however, the trend with DI was not as consistent as with PFI. OH planar Laser induced fluorescence images were also acquired for identification of the local flame front structure of all tested fuels

Kinetics of phloretin binding to phosphatidylcholine vesicle membranes.

The submillisecond kinetics for phloretin binding to unilamellar phosphatidylcholine (PC) vesicles was investigated using the temperature-jump technique. Spectrophotometric studies of the equilibrium binding performed at 328 nm demonstrated that phloretin binds to a single set of independent, equivalent sites on the vesicle with a dissociation constant of 8.0 microM and a lipid/site ratio of 4.0. The temperature of the phloretin-vesicle solution was jumped by 4 degrees C within 4 microseconds producing a monoexponential, concentration-dependent relaxation process with time constants in the 30--200-microseconds time range. An analysis of the concentration dependence of relaxation time constants at pH 7.30 and 24 degrees C yielded a binding rate constant of 2.7 X 10(8) M-1 s-1 and an unbinding constant of 2,900 s-1; approximately 66 percent of total binding sites are exposed at the outer vesicle surface. The value of the binding rate constant and three additional observations suggest that the binding kinetics are diffusion limited. The phloretin analogue, naringenin, which has a diffusion coefficient similar to phloretin yet a dissociation constant equal to 24 microM, bound to PC vesicle with the same rate constant as phloretin did. In addition, the phloretin-PC system was studied in buffers made one to six times more viscous than water by addition of sucrose or glycerol to the differ. The equilibrium affinity for phloretin binding to PC vesicles is independent of viscosity, yet the binding rate constant decreases with the expected dependence (kappa binding alpha 1/viscosity) for diffusion-limited processes. Thus, the binding rate constant is not altered by differences in binding affinity, yet depends upon the diffusion coefficient in buffer. Finally, studies of the pH dependence of the binding rate constant showed a dependence (kappa binding alpha [1 + 10pH-pK]) consistent with the diffusion-limited binding of a weak acid

In situ chemichromic studies of interactions between a lutetium bis-octaalkyl-substituted phthalocyanine and selected biological cofactors

This article is available open access through the publisher’s website at the link below. Copyright @ 2011 The Royal Society.Spin-coated films, approximately 100 nm thick, of a newly synthesized bis[octakis(octyl)phthalocyaninato] lutetium(III) complex on ultrasonically cleaned glass substrates exhibit pronounced chemichromic behaviour with potential application in healthcare. In situ kinetic optical absorption spectroscopic measurements show that the phthalocyanine Q-band is red shifted by 60 nm upon oxidation arising from exposure to bromine vapour. Recovery to the original state is achieved by the treatment of the oxidized films with nicotinamide adenine dinucleotide and l-ascorbic acid (vitamin C) in an aqueous solution containing 1.5 M lithium perchlorate. The neutralization process is found to be governed by first-order kinetics. The linear increase of the reduction rate with increasing concentration of cofactors provides a basis for calibration of analyte concentrations ranging from 3.5 mM down to 0.03 mM.Air Force Office of Scientific Research, Air Force Material Command, USAF and the Leverhulme Trust

Optimising workplace interventions for health and wellbeing: a commentary on the limitations of the public health perspective within the workplace health arena [forthcoming]

Purpose: This paper discusses contemporary approaches to workplace health and well-being, articulating key differences in the intervention architecture between public and workplace health contexts and implications for intervention design. Approach: Contemporary practice is discussed in light of calls for a paradigm shift in occupational health from a treatment orientation to an holistic approach focused on mitigation of the causes of ill health and the promotion of well-being. In practice, relatively few organizations have or seem able to engage with a broader perspective that encompasses challenges to health and well-being associated with contextual organizational drivers, e.g. job design/role, workload, systems of reward, leadership style and the underpinning climate. Drawing upon insights from public health and the workplace safety tradition, the scope for broadening the perspective on intervention (in terms of vectors of harm addressed, theory of change and intervention logic) is discussed. Findings: There are important differences in scope and options for intervention between public health and workplace health contexts. While there is scope to emulate public health practice, this should not constrain thinking over intervention opinions. Increased awareness of these key differences within work organizations, and an evidence-based epidemiological approach to learning has the potential to strengthen and broaden the approach to workplace health and well-being management. Originality/Value: We argue that approaches to workplace well-being interventions that selectively cross-fertilise and adapt elements of public health interventions offer promise for realising a broader change agenda and for building inherently healthy workplaces