How realistic are solar model atmospheres?

Recently, new solar model atmospheres have been developed to replace classical 1D LTE hydrostatic models and used to for example derive the solar chemical composition. We aim to test various models against key observational constraints. In particular, a 3D model used to derive the solar abundances, a 3D MHD model (with an imposed 10 mT vertical magnetic field), 1D models from the PHOENIX project, the 1D MARCS model, and the 1D semi-empirical model of Holweger & M\"uller. We confront the models with observational diagnostics of the temperature profile: continuum centre-to-limb variations (CLV), absolute continuum fluxes, and the wings of hydrogen lines. We also test the 3D models for the intensity distribution of the granulation and spectral line shapes. The predictions from the 3D model are in excellent agreement with the continuum CLV observations, performing even better than the Holweger & M\"uller model (constructed largely to fulfil such observations). The predictions of the 1D theoretical models are worse, given their steeper temperature gradients. For the continuum fluxes, predictions for most models agree well with the observations. No model fits all hydrogen lines perfectly, but again the 3D model comes ahead. The 3D model also reproduces the observed continuum intensity fluctuations and spectral line shapes very well. The excellent agreement of the 3D model with the observables reinforces the view that its temperature structure is realistic. It outperforms the MHD simulation in all diagnostics, implying that recent claims for revised abundances based on MHD modelling are premature. Several weaknesses in the 1D models are exposed. The differences between the PHOENIX LTE and NLTE models are small. We conclude that the 3D hydrodynamical model is superior to any of the tested 1D models, which gives further confidence in the solar abundance analyses based on it.Comment: 17 pages, 15 figures. Accepted for publication in A&

Empowered to gain a new foothold in life:A study of the meaning of participating in cardiac rehabilitation to patients afflicted by a minor heart attack

This study aimed to investigate what it means to patients afflicted by a minor heart attack to participate in cardiac rehabilitation (CR). CR is well-established internationally to support patients towards moving forward in satisfying, healthy, and well-functioning lives. Studies indicate that patients achieve improvement in quality of life when participating in CR. However, knowledge of how patients are supported during CR is sparse. Moreover, knowledge of what participating in CR means to patients afflicted by a minor heart attack is lacking. In-depth knowledge in this area is crucial in order to understand these patients’ particular gains and needs. In a phenomenological-hermeneutic frame field observations, focus group interviews, and individual interviews were conducted among 11 patients during and after their participation in CR. Field notes and transcribed interviews underwent three-phased interpretation. It was found that patients were supported to gain renewed balance in their lives during CR. Three themes were identified: (1) receiving a helpful but limited caring hand, (2) being supported to find new values in life, and (3) developing responsibility for the remaining time. The patients were carefully guided through a difficult time and supported to continue in healthy everyday lives. They were given hope which enabled them to find themselves a new foothold in life with respect to their own sense of well-being. This guidance and a sense of hopefulness were provided by heart specialists and more seasoned heart patients. In conclusion, patients were empowered to achieve a healthier lifestyle and improve their personal well-being during CR. However, structural barriers in the programme prevented adequate support regarding the patients’ total needs. Knowledge of the benefits of CR emphasizes the significance of the programme and highlights the importance of high inclusion. Efforts should be made to develop more flexible and longer lasting programmes and further involvement of relatives must be considered

Pay What You Want as a Marketing Strategy in Monopolistic and Competitive Markets

Pay What You Want (PWYW) can be an attractive marketing strategy to price discriminate between fair-minded and selfish customers, to fully penetrate a market without giving away the product for free, and to undercut competitors that use posted prices. We report on laboratory experiments that identify causal factors determining the willingness of buyers to pay voluntarily under PWYW. Furthermore, to see how competition affects the viability of PWYW, we implement markets in which a PWYW seller competes with a traditional seller. Finally, we endogenize the market structure and let sellers choose their pricing strategy. The experimental results show that outcome-based social preferences and strategic considerations to keep the seller in the market can explain why and how much buyers pay voluntarily to a PWYW seller. We find that PWYW can be viable in isolation, but it is less successful as a competitive strategy because it does not drive traditional posted-price sellers out of the market. Instead, the existence of a posted-price competitor reduces buyers’ payments and prevents the PWYW seller from fully penetrating the market. If given the choice, the majority of sellers opt for setting a posted price rather than a PWYW pricing. We discuss the implications of these results for the use of PWYW as a marketing strategy

Gamma-Irradiated Influenza Virus Uniquely Induces IFN-I Mediated Lymphocyte Activation Independent of the TLR7/MyD88 Pathway

Background: We have shown previously in mice, that infection with live viruses, including influenza/A and Semliki Forest virus (SFV), induces systemic partial activation of lymphocytes, characterized by cell surface expression of CD69 and CD86, but not CD25. This partial lymphocytes activation is mediated by type-I interferons (IFN-I). Importantly, we have shown that c-irradiated SFV does not induce IFN-I and the associated lymphocyte activation. Principal Findings: Here we report that, in contrast to SFV, c-irradiated influenza A virus elicits partial lymphocyte activation in vivo. Furthermore, we show that when using influenza viruses inactivated by a variety of methods (UV, ionising radiation and formalin treatment), as well as commercially available influenza vaccines, only c-irradiated influenza virus is able to trigger IFN-I-dependent partial lymphocyte activation in the absence of the TLR7/MyD88 signalling pathways. Conclusions: Our data suggest an important mechanism for the recognition of c-irradiated influenza vaccine by cytosolic receptors, which correspond with the ability of c-irradiated influenza virus to induce cross-reactive and cross-protective cytotoxic T cell responses.Yoichi Furuya, Jennifer Chan, En-Chi Wan, Aulikki Koskinen, Kerrilyn R. Diener, John D. Hayball, Matthias Regner, Arno Müllbacher, Mohammed Alsharif

Trouble at the top: The construction of a tenant identity in the governance of social housing organizations

The project of citizen governance has transformed the social housing sector in England where 20,000 tenants now sit as directors on the boards of housing associations, but the entrance of social housing tenants to the boardroom has aroused opposition from the chief executives of housing companies and triggered regulatory intervention from government inspectors. This paper investigates the cause of these tensions through a theoretical framework drawn from the work of feminist philosopher Judith Butler. It interprets housing governance as an identificatory project with the power to constitute tenant directors as regulated subjects, and presents evidence to suggest that this project of identity fails to completely enclose its subject, allowing tenant directors to engage in ‘identity work’ that threatens the supposed unity of the board. The paper charts the development of antagonism and political tension in the board rooms of housing companies to present an innovative account of the construction and contestation of identities in housing governance

Calibrating Convective properties of Solar-like Stars in the Kepler Field of View

Stellar models generally use simple parametrizations to treat convection. The most widely used parametrization is the so-called "Mixing Length Theory" where the convective eddy sizes are described using a single number, \alpha, the mixing-length parameter. This is a free parameter, and the general practice is to calibrate \alpha using the known properties of the Sun and apply that to all stars. Using data from NASA's Kepler mission we show that using the solar-calibrated \alpha is not always appropriate, and that in many cases it would lead to estimates of initial helium abundances that are lower than the primordial helium abundance. Kepler data allow us to calibrate \alpha for many other stars and we show that for the sample of stars we have studied, the mixing-length parameter is generally lower than the solar value. We studied the correlation between \alpha and stellar properties, and we find that \alpha increases with metallicity. We therefore conclude that results obtained by fitting stellar models or by using population-synthesis models constructed with solar values of \alpha are likely to have large systematic errors. Our results also confirm theoretical expectations that the mixing-length parameter should vary with stellar properties.Comment: 16 pages, 4 figures, accepted for publication in ApJ

Does shear wave ultrasound independently predict axillary lymph node metastasis in women with invasive breast cancer?

Shear wave elastography (SWE) shows promise as an adjunct to greyscale ultrasound examination in assessing breast masses. In breast cancer, higher lesion stiffness on SWE has been shown to be associated with features of poor prognosis. The purpose of this study was to assess whether lesion stiffness at SWE is an independent predictor of lymph node involvement. Patients with invasive breast cancer treated by primary surgery, who had undergone SWE examination were eligible. Data were retrospectively analysed from 396 consecutive patients. The mean stiffness values were obtained using the Aixplorer(®) ultrasound machine from SuperSonic Imagine Ltd. Measurements were taken from a region of interest positioned over the stiffest part of the abnormality. The average of the mean stiffness value obtained from each of two orthogonal image planes was used for analysis. Associations between lymph node involvement and mean lesion stiffness, invasive cancer size, histologic grade, tumour type, ER expression, HER-2 status and vascular invasion were assessed using univariate and multivariate logistic regression. At univariate analysis, invasive size, histologic grade, HER-2 status, vascular invasion, tumour type and mean stiffness were significantly associated with nodal involvement. Nodal involvement rates ranged from 7 % for tumours with mean stiffness <50 kPa to 41 % for tumours with a mean stiffness of >150 kPa. At multivariate analysis, invasive size, tumour type, vascular invasion, and mean stiffness maintained independent significance. Mean stiffness at SWE is an independent predictor of lymph node metastasis and thus can confer prognostic information additional to that provided by conventional preoperative tumour assessment and staging

Simulation of dimensionality effects in thermal transport

The discovery of nanostructures and the development of growth and fabrication techniques of one- and two-dimensional materials provide the possibility to probe experimentally heat transport in low-dimensional systems. Nevertheless measuring the thermal conductivity of these systems is extremely challenging and subject to large uncertainties, thus hindering the chance for a direct comparison between experiments and statistical physics models. Atomistic simulations of realistic nanostructures provide the ideal bridge between abstract models and experiments. After briefly introducing the state of the art of heat transport measurement in nanostructures, and numerical techniques to simulate realistic systems at atomistic level, we review the contribution of lattice dynamics and molecular dynamics simulation to understanding nanoscale thermal transport in systems with reduced dimensionality. We focus on the effect of dimensionality in determining the phononic properties of carbon and semiconducting nanostructures, specifically considering the cases of carbon nanotubes, graphene and of silicon nanowires and ultra-thin membranes, underlying analogies and differences with abstract lattice models.Comment: 30 pages, 21 figures. Review paper, to appear in the Springer Lecture Notes in Physics volume "Thermal transport in low dimensions: from statistical physics to nanoscale heat transfer" (S. Lepri ed.

Naturally p-hydroxybenzoylated lignins in palms

The industrial production of palm oil concurrently generates a substantial amount of empty fruit bunch (EFB) fibers that could be used as a feedstock in a lignocellulose-based biorefinery. Lignin byproducts generated by this process may offer opportunities for the isolation of value-added products, such as p-hydroxybenzoate (pBz), to help offset operating costs. Analysis of the EFB lignin by nuclear magnetic resonance (NMR) spectroscopy clearly revealed the presence of bound acetate and pBz, with saponification revealing that 1.1 wt% of the EFB was pBz; with a lignin content of 22.7 %, 4.8 % of the lignin is pBz that can be obtained as a pure component for use as a chemical feedstock. Analysis of EFB lignin by NMR and derivatization followed by reductive cleavage (DFRC) showed that pBz selectively acylates the γ-hydroxyl group of S units. This selectivity suggests that pBz, analogously with acetate in kenaf, p-coumarate in grasses, and ferulate in a transgenic poplar augmented with a feruloyl-CoA monolignol transferase (FMT), is incorporated into the growing lignin chain via its γ-p-hydroxybenzoylated monolignol conjugate. Involvement of such conjugates in palm lignification is proven by the observation of novel p-hydroxybenzoylated non-resinol β–β-coupled units in the lignins. Together, the data implicate the existence of p-hydroxybenzoyl-CoA:monolignol transferases that are involved in lignification in the various willows (Salix spp.), poplars and aspen (Populus spp., family Salicaceae), and palms (family Arecaceae) that have p-hydroxybenzoylated lignins. Even without enhancing the levels by breeding or genetic engineering, current palm oil EFB ‘wastes’ should be able to generate a sizeable stream of p-hydroxybenzoic acid that offers opportunities for the development of value-added products derived from the oil palm industry

Universal Rights and Wrongs

This paper argues for the important role of customers as a source of competitive advantage and firm growth, an issue which has been largely neglected in the resource-based view of the firm. It conceptualizes Penrose’s (1959) notion of an ‘inside track’ and illustrates how in-depth knowledge about established customers combines with joint problem-solving activities and the rapid assimilation of new and previously unexploited skills and resources. It is suggested that the inside track represents a distinct and perhaps underestimated way of generating rents and securing long-term growth. This also implies that the sources of sustainable competitive advantage in important respects can be sought in idiosyncratic interfirm relationships rather than within the firm itself