Showing papers by "Keele University published in 2012"

Grids of stellar models with rotation - I. Models from 0.8 to 120 M⊙ at solar metallicity (Z = 0.014)

Abstract: Aims. Many topical astrophysical research areas, such as the properties of planet host stars, the nature of the progenitors of different types of supernovae and gamma ray bursts, and the evolution of galaxies, require complete and homogeneous sets of stellar models at different metallicities in order to be studied during the whole of cosmic history. We present here a first set of models for solar metallicity, where the effects of rotation are accounted for in a homogeneous way.Methods. We computed a grid of 48 different stellar evolutionary tracks, both rotating and non-rotating, at Z = 0.014, spanning a wide mass range from 0.8 to 120 M ⊙ . For each of the stellar masses considered, electronic tables provide data for 400 stages along the evolutionary track and at each stage, a set of 43 physical data are given. These grids thus provide an extensive and detailed data basis for comparisons with the observations. The rotating models start on the zero-age main sequence (ZAMS) with a rotation rate υ ini /υ crit = 0.4. The evolution is computed until the end of the central carbon-burning phase, the early asymptotic giant branch (AGB) phase, or the core helium-flash for, respectively, the massive, intermediate, and both low and very low mass stars. The initial abundances are those deduced by Asplund and collaborators, which best fit the observed abundances of massive stars in the solar neighbourhood. We update both the opacities and nuclear reaction rates, and introduce new prescriptions for the mass-loss rates as stars approach the Eddington and/or the critical velocity. We account for both atomic diffusion and magnetic braking in our low-mass star models.Results. The present rotating models provide a good description of the average evolution of non-interacting stars. In particular, they reproduce the observed main-sequence width, the positions of the red giant and supergiant stars in the Hertzsprung-Russell (HR) diagram, the observed surface compositions and rotational velocities. Very interestingly, the enhancement of the mass loss during the red-supergiant stage, when the luminosity becomes supra-Eddington in some outer layers, help models above 15−20 M ⊙ to lose a significant part of their hydrogen envelope and evolve back into the blue part of the HR diagram. This result has interesting consequences for the blue to red supergiant ratio, the minimum mass for stars to become Wolf-Rayet stars, and the maximum initial mass of stars that explode as type II−P supernovae.

A new taxonomy for describing and defining adherence to medications

Abstract: Interest in patient adherence has increased in recent years, with a growing literature that shows the pervasiveness of poor adherence to appropriately prescribed medications. However, four decades of adherence research has not resulted in uniformity in the terminology used to describe deviations from prescribed therapies. The aim of this review was to propose a new taxonomy, in which adherence to medications is conceptualized, based on behavioural and pharmacological science, and which will support quantifiable parameters. A systematic literature review was performed using MEDLINE, EMBASE, CINAHL, the Cochrane Library and PsycINFO from database inception to 1 April 2009. The objective was to identify the different conceptual approaches to adherence research. Definitions were analyzed according to time and methodological perspectives. A taxonomic approach was subsequently derived, evaluated and discussed with international experts. More than 10 different terms describing medication-taking behaviour were identified through the literature review, often with differing meanings. The conceptual foundation for a new, transparent taxonomy relies on three elements, which make a clear distinction between processes that describe actions through established routines (‘Adherence to medications’, ‘Management of adherence’) and the discipline that studies those processes (‘Adherence-related sciences’). ‘Adherence to medications’ is the process by which patients take their medication as prescribed, further divided into three quantifiable phases: ‘Initiation’, ‘Implementation’ and ‘Discontinuation’. In response to the proliferation of ambiguous or unquantifiable terms in the literature on medication adherence, this research has resulted in a new conceptual foundation for a transparent taxonomy. The terms and definitions are focused on promoting consistency and quantification in terminology and methods to aid in the conduct, analysis and interpretation of scientific studies of medication adherence.

Acupuncture for Chronic Pain: Individual Patient Data Meta-analysis

Abstract: Methods: We conducted a systematic review to identify randomized controlled trials (RCTs) of acupuncture for chronic pain in which allocation concealment was determined unambiguously to be adequate. Individual patient data meta-analyses were conducted using data from 29 of 31 eligible RCTs, with a total of 17922 patients analyzed. Results: In the primary analysis, including all eligible RCTs, acupuncture was superior to both sham and noacupuncture control for each pain condition (P.001 for all comparisons). After exclusion of an outlying set ofRCTsthatstronglyfavoredacupuncture,theeffectsizes were similar across pain conditions. Patients receiving acupuncture had less pain, with scores that were 0.23 (95% CI, 0.13-0.33), 0.16 (95% CI, 0.07-0.25), and 0.15 (95% CI, 0.07-0.24) SDs lower than sham controls for back and neck pain, osteoarthritis, and chronic headache, respectively; the effect sizes in comparison to noacupuncturecontrolswere0.55(95%CI,0.51-0.58),0.57 (95% CI, 0.50-0.64), and 0.42 (95% CI, 0.37-0.46) SDs. Theseresultswererobusttoavarietyofsensitivityanalyses, including those related to publication bias. Conclusions: Acupuncture is effective for the treatment of chronic pain and is therefore a reasonable referraloption.Significantdifferencesbetweentrueandsham acupunctureindicatethatacupunctureismorethanaplacebo. However, these differences are relatively modest, suggesting that factors in addition to the specific effects of needling are important contributors to the therapeutic effects of acupuncture.

The development of bulky palladium NHC complexes for the most-challenging cross-coupling reactions.

Abstract: Palladium-catalyzed cross-coupling reactions enable organic chemists to form C-C bonds in targeted positions and under mild conditions. Although phosphine ligands have been intensively researched, in the search for even better cross-coupling catalysts attention has recently turned to the use of N-heterocyclic carbene (NHC) ligands, which form a strong bond to the palladium center. PEPPSI (pyridine-enhanced precatalyst preparation, stabilization, and initiation) palladium precatalysts with bulky NHC ligands have established themselves as successful alternatives to palladium phosphine complexes. This Review shows the success of these species in Suzuki-Miyaura, Negishi, and Stille-Migita cross-couplings as well as in amination and sulfination reactions.

The next generation virgo cluster survey (ngvs). i. introduction to the survey

Abstract: The Next Generation Virgo Cluster Survey (NGVS) is a program that uses the 1 deg2 MegaCam instrument on the Canada-France-Hawaii Telescope to carry out a comprehensive optical imaging survey of the Virgo cluster, from its core to its virial radius—covering a total area of 104 deg2—in the u*griz bandpasses. Thanks to a dedicated data acquisition strategy and processing pipeline, the NGVS reaches a point-source depth of g ≈ 25.9 mag (10σ) and a surface brightness limit of μ g ~ 29 mag arcsec–2 (2σ above the mean sky level), thus superseding all previous optical studies of this benchmark galaxy cluster. In this paper, we give an overview of the technical aspects of the survey, such as areal coverage, field placement, choice of filters, limiting magnitudes, observing strategies, data processing and calibration pipelines, survey timeline, and data products. We also describe the primary scientific topics of the NGVS, which include: the galaxy luminosity and mass functions; the color-magnitude relation; galaxy scaling relations; compact stellar systems; galactic nuclei; the extragalactic distance scale; the large-scale environment of the cluster and its relationship to the Local Supercluster; diffuse light and the intracluster medium; galaxy interactions and evolutionary processes; and extragalactic star clusters. In addition, we describe a number of ancillary programs dealing with "foreground" and "background" science topics, including the study of high-inclination trans-Neptunian objects; the structure of the Galactic halo in the direction of the Virgo Overdensity and Sagittarius Stream; the measurement of cosmic shear, galaxy-galaxy, and cluster lensing; and the identification of distant galaxy clusters, and strong-lensing events.

Experiential learning: AMEE Guide No. 63

Abstract: This Guide provides an overview of educational theory relevant to learning from experience. It considers experience gained in clinical workplaces from early medical student days through qualification to continuing professional development. Three key assumptions underpin the Guide: learning is ‘situated’; it can be viewed either as an individual or a collective process; and the learning relevant to this Guide is triggered by authentic practice-based experiences. We first provide an overview of the guiding principles of experiential learning and significant historical contributions to its development as a theoretical perspective. We then discuss socio-cultural perspectives on experiential learning, highlighting their key tenets and drawing together common threads between theories. The second part of the Guide provides examples of learning from experience in practice to show how theoretical stances apply to clinical workplaces. Early experience, student clerkships and residency training are discussed in turn. We end with a summary of the current state of understanding.

Adherence to antiretroviral therapy during and after pregnancy in low-income, middle-income, and high-income countries: a systematic review and meta-analysis.

Abstract: Objective: To estimate antiretroviral therapy (ART) adherence rates during pregnancy and postpartum in high-income, middle-income, and low-income countries. Design: Systematic review and meta-analysis. Methods: MEDLINE, EMBASE, SCI Web of Science, NLM Gateway, and Google scholar databases were searched. We included all studies reporting adherence rates as a primary or secondary outcome among HIV-infected pregnant women. Two independent reviewers extracted data on adherence and study characteristics. A random-effects model was used to pool adherence rates; sensitivity, heterogeneity, and publication bias were assessed. Results: Of 72 eligible articles, 51 studies involving 20153 HIV-infected pregnant women were included. Most studies were from United States (n ¼14, 27%) followed by Kenya (n ¼6, 12%), South Africa (n ¼5, 10%), and Zambia (n ¼5, 10%). The threshold defining good adherence to ART varied across studies (>80, >90, >95, 100%). A pooled analysis of all studies indicated a pooled estimate of 73.5% [95% confidence interval (CI) 69.3‐77.5%] of pregnant women who had adequate (>80%) ART adherence. The pooled proportion of women with adequate adherence levels was higher during the antepartum (75.7%, 95% CI 71.5‐79.7%) than during postpartum (53.0%, 95% CI 32.8‐72.7%; P ¼0.005). Selected reported barriers for nonadherence included physical, economic and emotional stresses, depression (especially postdelivery), alcohol or drug use, and ART dosing frequency or pill burden. Conclusion: Our findings indicate that only 73.5% of pregnant women achieved optimal ART adherence. Reaching adequate ART adherence levels was a challenge in pregnancy, but especially during the postpartum period. Further research to

Ageing in urban environments: Developing ‘age-friendly’ cities

Abstract: Developing environments responsive to the aspirations and needs of older people has become a major concern for social and public policy. This article aims to provide a critical perspective on what ...

Kirkpatrick's levels and education evidence'

Abstract: Medical Education 2012: 46: 97–106 Objectives This study aims to review, critically, the suitability of Kirkpatrick’s levels for appraising interventions in medical education, to review empirical evidence of their application in this context, and to explore alternative ways of appraising research evidence. Methods The mixed methods used in this research included a narrative literature review, a critical review of theory and qualitative empirical analysis, conducted within a process of cooperative inquiry. Results Kirkpatrick’s levels, introduced to evaluate training in industry, involve so many implicit assumptions that they are suitable for use only in relatively simple instructional designs, short-term endpoints and beneficiaries other than learners. Such conditions are met by perhaps one-fifth of medical education evidence reviews. Under other conditions, the hierarchical application of the levels as a critical appraisal tool adds little value and leaves reviewers to make global judgements of the trustworthiness of the data. Conclusions Far from defining a reference standard critical appraisal tool, this research shows that ‘quality’ is defined as much by the purpose to which evidence is to be put as by any invariant and objectively measurable quality. Pending further research, we offer a simple way of deciding how to appraise the quality of medical education research.

Experiential learning: Transforming theory into practice

Abstract: Whilst much is debated about the importance of experiential learning in curriculum development, the concept only becomes effective if it is applied in an appropriate way. We believe that this effectiveness is directly related to a sound understanding of the theory, supporting the learning. The purpose of this article is to introduce readers to the theories underpinning experiential learning, which are then expanded further in an AMEE Guide, which considers the theoretical basis of experiential learning from a social learning, constructionist perspective and applies it to three stages of medical education: early workplace experience, clerkships and residency. This article argues for the importance and relevance of experiential learning and addresses questions that are commonly asked about it. First, we answer the questions 'what is experiential learning?' and 'how does it relate to social learning theory?' to orientate readers to the principles on which our arguments are based. Then, we consider why those ideas (theories) are relevant to educators--ranging from those with responsibilities for curriculum design to 'hands-on' teachers and workplace supervisors. The remainder of this article discusses how experiential learning theories and a socio-cultural perspective can be applied in practice. We hope that this will give readers a taste for our more detailed AMEE Guide and the further reading recommended at the end of it.

Are snoRNAs and snoRNA host genes new players in cancer

Abstract: Small nucleolar RNAs (snoRNAs) have long been considered important but unglamorous elements in the production of the protein synthesis machinery of the cell. Recently, however, several independent lines of evidence have indicated that these non-coding RNAs might have crucial roles in controlling cell behaviour, and snoRNA dysfunction could consequently contribute to oncogenesis in previously unsuspected ways.

Grids of stellar models with rotation - II. WR populations and supernovae/GRB progenitors at Z = 0.014

Abstract: Context. In recent years, many very interesting observations have appeared concerning the positions of Wolf-Rayet (WR) stars in the Hertzsprung-Russell diagram (HRD), the number ratios of WR stars, the nature of Type Ibc supernova (SN) progenitors, long and soft gamma ray bursts (LGRB), and the frequency of these various types of explosive events. These observations represent key constraints on massive star evolution.Aims. We study, in the framework of the single-star evolutionary scenario, how rotation modifies the evolution of a given initial mass star towards the WR phase and how it impacts the rates of Type Ibc SNe. We also discuss the initial conditions required to obtain collapsars and LGRB.Methods. We used a recent grid of stellar models computed with and without rotation to make predictions concerning the WR populations and the frequency of different types of core-collapse SNe. Current rotating models were checked to provide good fits to the following features: solar luminosity and radius at the solar age, main-sequence width, red-giant and red-supergiant (RSG) positions in the HRD, surface abundances, and rotational velocities.Results. Rotating stellar models predict that about half of the observed WR stars and at least half of the Type Ibc SNe may be produced through the single-star evolution channel. Rotation increases the duration of the WNL and WNC phases, while reducing those of the WNE and WC phases, as was already shown in previous works. Rotation increases the frequency of Type Ic SNe. The upper mass limit for Type II-P SNe is ~19.0 M ⊙ for the non rotating models and ~16.8 M ⊙ for the rotating ones. Both values agree with observations. Moreover, present rotating models provide a very good fit to the progenitor of SN 2008ax. We discuss future directions of research for further improving the agreement between the models and the observations. We conclude that the mass-loss rates in the WNL and RSG phases are probably underestimated at present. We show that up to an initial mass of 40 M ⊙ , a surface magnetic field inferior to about 200 G may be sufficient to produce some braking. Much lower values are needed at the red supergiant stage. We suggest that the presence/absence of any magnetic braking effect may play a key role in questions regarding rotation rates of young pulsars and the evolution leading to LGRBs.

Biocompatibility and toxicity of magnetic nanoparticles in regenerative medicine

Abstract: Regenerative medicine is a pioneering field aimed at restoring and regenerating the function of damaged cells, organs and tissues in order to establish normal function. It demands the cross communication of disciplines to develop effective therapeutic stem cell based therapies. Nanotechnology has been instrumental in the development and translation of basic research to the clinically relevant therapies. In particular, magnetic nanoparticles (MNPs) have been applied to tag, track and activate stem cells offering an effective means of monitoring in vitro and in vivo behaviour. MNPs are comprised of an iron oxide core with a biocompatible biological polymer. Safety is an issue of constant concern and emphasises on the importance of investigating the issue of toxicity. Any indication of toxicity can ultimately limit the therapeutic efficiency of the therapy. Toxicity is highly dependent on the physical, chemical and structural properties of the MNP itself as well as dose and intended use. Few in vitro studies have reported adverse effects of MNP on cells at in vitro in therapeutic doses. However, long term in vivo studies have not been studied as extensively. This review aims to summarise current research in this topic highlighting commonly used toxicity assays to investigate this.

Accurate fundamental parameters and detailed abundance patterns from spectroscopy of 93 solar-type Kepler targets

Abstract: We present a detailed spectroscopic study of 93 solar-type stars that are targets of the NASA/Kepler mission and provide detailed chemical composition of each target. We find that the overall metallicity is well represented by Fe lines. Relative abundances of light elements (CNO) and α elements are generally higher for low-metallicity stars. Our spectroscopic analysis benefits from the accurately measured surface gravity from the asteroseismic analysis of the Kepler light curves. The accuracy on the log g parameter is better than 0.03 dex and is held fixed in the analysis. We compare our T eff determination with a recent colour calibration of V T − KS [TYCHO V magnitude minus Two Micron All Sky Survey (2MASS) KS magnitude] and find very good agreement and a scatter of only 80 K, showing that for other nearby Kepler targets, this index can be used. The asteroseismic log g values agree very well with the classical determination using Fe I–Fe II balance, although we find a small systematic

Development and Application of a New Measure of Employee Engagement: the ISA Engagement Scale

Abstract: Effective measure of employee engagement is relevant to human resource development (HRD) theory and practice. We build on Kahn's (1990, Psychological conditions of personal engagement and disengagement at work, Academy of Management Journal 33: 692–724) theory and develop a model of engagement that has three requirements: a work-role focus, activation and positive affect. This model was operationalized in a new measure: the Intellectual, Social, Affective Engagement Scale (ISA Engagement Scale) comprising three facets: intellectual, social and affective engagement. Data from Study 1 (278 employees from a manufacturing organization) showed that the scale and its sub-scales have internal reliability. Study 2 examined data from 683 employees in a retail organization. The internal reliability was confirmed and construct validity was demonstrated. The new scale had positive associations with three theoretically and empirically important outcomes: task performance, organizational citizenship behaviour (OCB) and turnover intentions. Implications are considered for academic enquiry into the engagement process, and for HRD practices that enhance the experience of work.

Non-standard s process in low metallicity massive rotating stars

Abstract: Context. Rotation is known to have a strong impact on the nucleosynthesis of light elements in massive stars, mainly by inducing mixing in radiative zones. In particular, rotation boosts the primary nitrogen production, and models of rotating stars are able to reproduce the nitrogen observed in low-metallicity halo stars. Aims. Here we present the first grid of stellar models for rotating massive stars at low metallicity, where a full s-process network is used to study the impact of rotation-induced mixing on the neutron capture nucleosynthesis of heavy elements. Methods. We used the Geneva stellar evolution code that includes an enlarged reaction network with nuclear species up to bismuth to calculate 25 M ⊙ models at three different metallicities (Z = 10-3 ,10-5 , and 10-7 ) and with different initial rotation rates. Results. First, we confirm that rotation-induced mixing (shear) between the convective H-shell and He-core leads to a large production of primary 22 Ne (0.1 to 1% in mass fraction), which is the main neutron source for the s-process in massive stars. Therefore rotation boosts the s-process in massive stars at all metallicities. Second, the neutron-to-seed ratio increases with decreasing Z in models including rotation, which leads to the complete consumption of all iron seeds at metallicities below Z = 10-3 by the end of core He-burning. Thus at low Z , the iron seeds are the main limitation for this boosted s-process. Third, as the metallicity decreases, the production of elements up to the Ba peak increases at the expense of the elements of the Sr peak. We studied the impact of the initial rotation rate and of the highly uncertain 17 O(α,γ ) rate (which strongly affects the strength of 16 O as a neutron poison) on our results. This study shows that rotating models can produce significant amounts of elements up to Ba over a wide range of Z , which has important consequences for our understanding of the formation of these elements in low-metallicity environments like the halo of our galaxy and globular clusters. Fourth, compared to the He-core, the primary 22 Ne production induced by rotation in the He-shell is even higher (greater than 1% in mass fraction at all metallicities), which could open the door for an explosive neutron capture nucleosynthesis in the He-shell, with a primary neutron source.

The TRAPPIST survey of southern transiting planets. I. Thirty eclipses of the ultra-short period planet WASP-43 b

Abstract: We present twenty-three transit light curves and seven occultation light curves for the ultra-short period planet WASP -43 b, in addition to eight new measurements of the radial velocity of the star. Thanks to this extensive data set, we improve significantly t he parameters of the system. Notably, the largely improved precision on the stellar density (2.41± 0.08ρ⊙) combined with constraining the age to be younger than a Hubble time allows us to break the degeneracy of the stellar solution mentioned in the discovery paper. The resulting stellar mass and size are 0.717± 0.025 M⊙ and 0.667± 0.011 R⊙. Our deduced physical parameters for the planet are 2.034± 0.052 MJup and 1.036± 0.019 RJup. Taking into account its level of irradiation, the high dens ity of the planet favors an old age and a massive core. Our deduced orbital eccentricity, 0.0035 +0.0060 −0.0025 , is consistent with a fully circularized orbit. We detect th e emission of the planet at 2.09µm at better than 11-σ, the deduced occultation depth being 1560± 140 ppm. Our detection of the occultation at 1.19µm is marginal (790± 320 ppm) and more observations are needed to confirm it. We pla ce a 3-σ upper limit of 850 ppm on the depth of the occultation at∼0.9µm. Together, these results strongly favor a poor redistribu tion of the heat to the night-side of the planet, and marginally favor a model with no day-side temperature inversion.

Evidence for ultrafast outflows in radio-quiet AGNs — III. Location and energetics

Abstract: Using the results of a previous X-ray photo-ionization modelling of blue-shifted Fe K absorption lines on a sample of 42 local radio-quiet AGNs observed with XMM-Newton, in this letter we estimate the location and energetics of the associated ultrafast outflows (UFOs). Due to significant uncertainties, we are essentially able to place only lower/upper limits. On average, their location is in the interval approx.0.0003-0.03pc (approx.10(exp 2)-10(exp 4)tau(sub s) from the central black hole, consistent with what is expected for accretion disk winds/outflows. The mass outflow rates are constrained between approx.0.01- 1 Stellar Mass/y, corresponding to approx. or >5-10% of the accretion rates. The average lower-upper limits on the mechanical power are logE(sub K) approx. or = 42.6-44.6 erg/s. However, the minimum possible value of the ratio between the mechanical power and bolometric luminosity is constrained to be comparable or higher than the minimum required by simulations of feedback induced by winds/outflows. Therefore, this work demonstrates that UFOs are indeed capable to provide a significant contribution to the AGN r.osmological feedback, in agreement with theoretical expectations and the recent observation of interactions between AGN outflows and the interstellar medium in several Seyferts galaxies .

The Density of EAAC1 (EAAT3) Glutamate Transporters Expressed by Neurons in the Mammalian CNS

Abstract: The extracellular levels of excitatory amino acids are kept low by the action of the glutamate transporters. Glutamate/aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) are the most abundant subtypes and are essential for the functioning of the mammalian CNS, but the contribution of the EAAC1 subtype in the clearance of synaptic glutamate has remained controversial, because the density of this transporter in different tissues has not been determined. We used purified EAAC1 protein as a standard during immunoblotting to measure the concentration of EAAC1 in different CNS regions. The highest EAAC1 levels were found in the young adult rat hippocampus. Here, the concentration of EAAC1 was ∼0.013 mg/g tissue (∼130 molecules μm−3), 100 times lower than that of GLT-1. Unlike GLT-1 expression, which increases in parallel with circuit formation, only minor changes in the concentration of EAAC1 were observed from E18 to adulthood. In hippocampal slices, photolysis of MNI-d-aspartate (4-methoxy-7-nitroindolinyl-d-aspartate) failed to elicit EAAC1-mediated transporter currents in CA1 pyramidal neurons, and d-aspartate uptake was not detected electron microscopically in spines. Using EAAC1 knock-out mice as negative controls to establish antibody specificity, we show that these relatively small amounts of EAAC1 protein are widely distributed in somata and dendrites of all hippocampal neurons. These findings raise new questions about how so few transporters can influence the activation of NMDA receptors at excitatory synapses.

Predictions for mass-loss rates and terminal wind velocities of massive O-type stars

Abstract: Context. Mass loss from massive stars forms an important aspect of the evolution of massive stars, as well as for the enrichment of the surrounding interstellar medium. Aims. Our goal is to predict accurate mass-loss rates and terminal wind velocities. These quantities can be compared to empirical values, thereby testing radiation-driven wind models. One specific topical issue is that of the so-called “weak-wind problem”, where empirically derived mass-loss rates and (modified) wind momenta fall orders of magnitude short of predicted values. Methods. We employ an established Monte Carlo model and a recently suggested new line acceleration formalism to solve the wind dynamics more consistently. Results. We provide a new grid of mass-loss rates and terminal wind velocities of O-type stars, and compare the values to empirical results. Our models fail to provide mass-loss rates for main-sequence stars below a luminosity of log(L/L� ) = 5.2, where we appear to run into a fundamental limit. At luminosities below this critical value there is insufficient momentum transferred to the wind in the region below the sonic point in order to kick-start the acceleration of the flow. This problem occurs at almost the exact location of the onset of the weak-wind problem. For O dwarfs, the boundary between being able to start a wind, and failing to do so, is at spectral type O6/O6.5. The direct cause of this failure for O6.5 stars is a combination of the lower luminosity and a lack of Fev lines at the base of the wind. This might indicate that – in addition to radiation pressure – another mechanism is required to provide the necessary driving to initiate the wind acceleration. Conclusions. For stars more luminous than 10 5.2 L� , our new mass-loss rates are in excellent agreement with the mass-loss prescription by Vink et al. (2000, A&A, 362, 295) using our terminal wind velocities as input to this recipe. This implies that the main assumption entering the method of the Vink et al. prescriptions – i.e. that the momentum equation is not explicitly solved for – does not compromise the reliability of the Vink et al. results for this part of parameter space. Finally, our new models predict terminal velocities that are typically 35 and 45 percent larger than observed values. Such over-predictions are similar to those from (modified) CAK-theory.

Grids of stellar models with rotation II. WR populations and supernovae/GRB progenitors at Z = 0.014

Abstract: We used a recent grid of stellar models computed with and without rotation to make predictions concerning the WR populations and the frequency of different types of core-collapse SNe. Current rotating models were checked to provide good fits to the following features: solar luminosity and radius at the solar age, main-sequence width, red-giant and red-supergiant (RSG) positions in the HRD, surface abundances, and rotational velocities. Rotating stellar models predict that about half of the observed WR stars and at least half of the type Ibc SNe may be produced through the single-star evolution channel. Rotation increases the duration of the WNL and WNC phases, while reducing those of the WNE and WC phases, as was already shown in previous works. Rotation increases the frequency of type Ic SNe. The upper mass limit for type II-P SNe is \sim 19.0 MSun for the non rotating models and \sim 16.8 MSun for the rotating ones. Both values agree with observations. Moreover, present rotating models provide a very good fit to the progenitor of SN 2008ax. We discuss future directions of research for further improving the agreement between the models and the observations. We conclude that the mass-loss rates in the WNL and RSG phases are probably underestimated at present. We show that up to an initial mass of 40 M\odot, a surface magnetic field inferior to about 200 G may be sufficient to produce some braking. Much lower values are needed at the red supergiant stage. We suggest that the presence/absence of any magnetic braking effect may play a key role in questions regarding rotation rates of young pulsars and the evolution leading to LGRBs.

Individual and contextual factors associated with low childhood immunisation coverage in Sub-Saharan Africa: A multilevel analysis

Abstract: Background In 2010, more than six million children in sub-Saharan Africa did not receive the full series of three doses of the diphtheria-tetanus-pertussis vaccine by one year of age. An evidence-based approach to addressing this burden of un-immunised children requires accurate knowledge of the underlying factors. We therefore developed and tested a model of childhood immunisation that includes individual, community and country-level characteristics. Method and Findings We conducted multilevel logistic regression analysis of Demographic and Health Survey data for 27,094 children aged 12–23 months, nested within 8,546 communities from 24 countries in sub-Saharan Africa. According to the intra-country and intra-community correlation coefficient implied by the estimated intercept component variance, 21% and 32% of the variance in unimmunised children were attributable to country- and community-level factors respectively. Children born to mothers (OR 1.35, 95%CI 1.18 to 1.53) and fathers (OR 1.13, 95%CI 1.12 to 1.40) with no formal education were more likely to be unimmunised than those born to parents with secondary or higher education. Children from the poorest households were 36% more likely to be unimmunised than counterparts from the richest households. Maternal access to media significantly reduced the odds of children being unimmunised (OR 0.94, 95%CI 0.94 to 0.99). Mothers with health seeking behaviours were less likely to have unimmunised children (OR 0.56, 95%CI 0.54 to 0.58). However, children from urban areas (OR 1.12, 95% CI 1.01 to 1.23), communities with high illiteracy rates (OR 1.13, 95% CI 1.05 to 1.23), and countries with high fertility rates (OR 4.43, 95% CI 1.04 to 18.92) were more likely to be unimmunised. Conclusion We found that individual and contextual factors were associated with childhood immunisation, suggesting that public health programmes designed to improve coverage of childhood immunisation should address people, and the communities and societies in which they live.

Direct transplantation of mesenchymal stem cells into the knee joints of Hartley strain guinea pigs with spontaneous osteoarthritis

Abstract: Introduction Mesenchymal stem cells (MSCs) can differentiate into various connective tissue cells. Several techniques have been used for the clinical application of MSCs in articular cartilage repair; however, there are many issues associated with the selection of the scaffold material, including its ability to support cell viability and differentiation and its retention and degradation in situ. The application of MSCs via a scaffold also requires a technically demanding surgical procedure. The aim of this study was to test the outcome of intra-articular transplantation of mesenchymal stem cells suspended in hyaluronic acid (HA) in the knee joints of Hartley strain guinea pigs with spontaneous osteoarthritis (OA).

Evidence for ultra-fast outflows in radio-quiet AGNs: III - location and energetics

Abstract: Using the results of a previous X-ray photo-ionization modelling of blue-shifted Fe K absorption lines on a sample of 42 local radio-quiet AGNs observed with XMM-Newton, in this letter we estimate the location and energetics of the associated ultra-fast outflows (UFOs). Due to significant uncertainties, we are essentially able to place only lower/upper limits. On average, their location is in the interval ~0.0003-0.03pc (~10^2-10^4 r_s) from the central black hole, consistent with what is expected for accretion disk winds/outflows. The mass outflow rates are constrained between ~0.01-1 M_{\odot} yr^{-1}, corresponding to >5-10% of the accretion rates. The average lower-upper limits on the mechanical power are log\dot{E}_K~42.6-44.6 erg s^{-1}. However, the minimum possible value of the ratio between the mechanical power and bolometric luminosity is constrained to be comparable or higher than the minimum required by simulations of feedback induced by winds/outflows. Therefore, this work demonstrates that UFOs are indeed capable to provide a significant contribution to the AGN cosmological feedback, in agreement with theoretical expectations and the recent observation of interactions between AGN outflows and the interstellar medium in several Seyferts galaxies.

Functional foods and nutraceuticals in the primary prevention of cardiovascular diseases.

Abstract: Cardiovascular disease (CVD) is now the leading cause of death globally and is a growing health concern. Dietary factors are important in the pathogenesis of CVD and may to a large degree determine CVD risk, but have been less extensively investigated. Functional foods are those that are thought to have physiological benefits and/or reduce the risk of chronic disease beyond their basic nutritional functions. The food industry has started to market products labelled as "functional foods." Although many review articles have focused on individual dietary variables as determinants of CVD that can be modified to reduce the risk of CVD, the aim of this current paper was to examine the impact of functional foods in relation to the development and progression of CVD. Epidemiologic studies have demonstrated the association between certain dietary patterns and cardiovascular health. Research into the cardio-protective potential of their dietary components might support the development of functional foods and nutraceuticals. This paper will also compare the effect of individual bioactive dietary compounds with the effect of some dietary patterns in terms of their cardiovascular protection.

The rheological and structural properties of Fmoc-peptide-based hydrogels: the effect of aromatic molecular architecture on self-assembly and physical characteristics.

Abstract: Biocompatible hydrogels are of high interest as a class of biomaterials for tissue engineering, regenerative medicine, and controlled drug delivery. These materials offer three-dimensional scaffolds to support the growth of cells and development of hierarchical tissue structures. Fmoc-peptides were previously demonstrated as attractive building blocks for biocompatible hydrogels. Here, we further investigate the biophysical properties of Fmoc-peptide-based hydrogels for medical applications. We describe the structural and thermal properties of these Fmoc-peptides, as well as their self-assembly process. Additionally, we study the role of interactions between aromatic moieties in the self-assembly process and on the physical and structural properties of the hydrogels.

Seven transiting hot Jupiters from WASP-South, Euler and TRAPPIST: WASP-47b, WASP-55b, WASP-61b, WASP-62b, WASP-63b, WASP-66b and WASP-67b

Abstract: We present seven new transiting hot Jupiters from the WASP-South survey. The planets are all typical hot Jupiters orbiting stars from F4 to K0 with magnitudes of V = 10.3–12.5. The orbital periods are all in the range of 3.9–4.6 d, the planetary masses range from 0.4 to 2.3 MJup and the radii from 1.1 to 1.4 RJup. In line with known hot Jupiters, the planetary densities range from Jupiter-like to inflated (ρ = 0.13–1.07ρJup). We use the increasing numbers of known hot Jupiters to investigate the distribution of their orbital periods and the 3–4 d ‘pile-up’.