Anomaly mediated neutrino-photon interactions at finite baryon density

We propose new physical processes based on the axial vector anomaly and described by the Wess-Zumino-Witten term that couples the photon, Z-boson, and the omega-meson. The interaction takes the form of a pseudo-Chern-Simons term, $\sim \epsilon_{\mu\nu\rho\sigma}\omega^\mu Z^\nu F^{\rho\sigma}$. This term induces neutrino-photon interactions at finite baryon density via the coupling of the Z-boson to neutrinos. These interactions may be detectable in various laboratory and astrophysical arenas. The new interactions may account for the MiniBooNE excess. They also produce a competitive contribution to neutron star cooling at temperatures >10^9 K. These processes and related axion--photon interactions at finite baryon density appear to be relevant in many astrophysical regimes.Comment: 4 pages, 2 figures; references adde

The generator coordinate method in time-dependent density-functional theory: memory made simple

The generator coordinate (GC) method is a variational approach to the quantum many-body problem in which interacting many-body wave functions are constructed as superpositions of (generally nonorthogonal) eigenstates of auxiliary Hamiltonians containing a deformation parameter. This paper presents a time-dependent extension of the GC method as a new approach to improve existing approximations of the exchange-correlation (XC) potential in time-dependent density-functional theory (TDDFT). The time-dependent GC method is shown to be a conceptually and computationally simple tool to build memory effects into any existing adiabatic XC potential. As an illustration, the method is applied to driven parametric oscillations of two interacting electrons in a harmonic potential (Hooke's atom). It is demonstrated that a proper choice of time-dependent generator coordinates in conjunction with the adiabatic local-density approximation reproduces the exact linear and nonlinear two-electron dynamics quite accurately, including features associated with double excitations that cannot be captured by TDDFT in the adiabatic approximation.Comment: 10 pages, 13 figure

Zinc abundances in Galactic bulge field red giants: implications for DLA systems

Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman-alpha systems, permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman-alpha systems, in order to better understand the chemical evolution in these environments. High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We find [Zn/Fe]=+0.24+-0.02 in the range -1.3 < [Fe/H] < -0.5 and [Zn/Fe]=+0.06+-0.02 in the range -0.5 < [Fe/H] -0.1, it shows a spread of -0.60 < [Zn/Fe] < +0.15, with most of these stars having low [Zn/Fe]<0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge.Comment: Accepted in Astronomy & Astrophysics, in press Date of acceptance: 13/05/2015. 19 pages, 14 Figs in Astronomy & Astrophysics, 201

An In Vitro Comparison of A Novel Self-Assembling Peptide Matrix Gel and Selected Desensitizing Toothpastes in Reducing Fluid Flow by Dentine Tubular Occlusion

Objectives: The objective of this explorative in vitro study was to evaluate the ability of a novel self-assembling peptide matrix gel with calcium phosphate in effectively occluding dentine tubules compared to selected desensitizing toothpastes. Methods: Mid-coronal dentine discs with a thickness of 1 mm were sectioned from caries-free human molars. The discs were etched with 6% citric acid for 2 minutes, halved and subjected to a 2-minute brushing with a novel gel (SAPM) and three selected desensitizing toothpastes ([SRP], [SRR] and [CSP]). The ability of the desensitizing gel and toothpastes to occlude the dentine tubules was assessed and compared before and after brushing using Scanning Electron Microscopy (SEM) on both etched and fractured dentine surfaces. The SEM observations were supplemented by hydraulic conductance measurements using a modified Pashley model before and after tooth brushing (n=5). Results: The results demonstrated that there was a reduction in both the number and the diameter of the open dentine tubules, which was evident for all the treated dentine discs. The particles that occluded the open dentine tubules, however had different morphologies and distribution. The selfassembling peptide matrix gel (SAPM) demonstrated greater reduction in the number of open tubules compared to the other desensitizing toothpastes. Reductions in the hydraulic conductance measurements were observed for all tested materials (mean [SD, %]: SAPM 55.1 [12.5], SRP 64.9 [18.5], SRR 39.1 [17.1] and CSP 27.6 [6.8]). No statistically differences were observed between the SAPM and SRP, SRR toothpastes (paired t-Test; ≤0.05) although a significant difference was noted between the SAPM and the CSP toothpastes. There was an overall trend for reduction for the SAPM compared to the SRR toothpaste. Conclusion: The results would suggest that a novel self-assembling peptide matrix gel (SAPM) was effective in blocking the dentine tubules and may therefore have the potential to be an effective desensitizing product for the treatment of Dentine Hypersensitivity

Dentine Tubule Occlusion by Novel Bioactive Glass-Based Toothpastes.

There are numerous over-the-counter (OTC) and professionally applied (in-office) products and techniques currently available for the treatment of dentine hypersensitivity (DH), but more recently, the use of bioactive glasses in toothpaste formulations have been advocated as a possible solution to managing DH. Aim. The aim of the present study, therefore, was to compare several bioactive glass formulations to investigate their effectiveness in an established in vitro model. Materials and Methods. A 45S5 glass was synthesized in the laboratory together with several other glass formulations: (1) a mixed glass (fluoride and chloride), (2) BioMinF, (3) a chloride glass, and (4) an amorphous chloride glass. The glass powders were formulated into five different toothpaste formulations. Dentine discs were sectioned from extracted human teeth and prepared for the investigation by removing the cutting debris (smear layer) following sectioning using a 6% citric acid solution for 2 minutes. Each disc was halved to provide test and control halves for comparison following the brushing of the five toothpaste formulations onto the test halves for each toothpaste group. Following the toothpaste application, the test discs were immersed in either artificial saliva or exposed to an acid challenge. Results. The dentine samples were analyzed using scanning electron microscopy (SEM), and observation of the SEM images indicated that there was good surface coverage following artificial saliva immersion. Furthermore, although the acid challenge removed the hydroxyapatite layer on the dentine surface for most of the samples, except for the amorphous chloride glass, there was evidence of tubular occlusion in the dentine tubules. Conclusions. The conclusions from the study would suggest that the inclusion of bioactive glass into a toothpaste formulation may be an effective approach to treat DH

The Chemical Enrichment History of the Small Magellanic Cloud and Its Gradients

We present stellar metallicities derived from Ca II triplet spectroscopy in over 350 red giant branch stars in 13 fields distributed in different positions in the SMC, ranging from $\sim$1\arcdeg\@ to $\sim$4\arcdeg\@ from its center. In the innermost fields the average metallicity is [Fe/H] $\sim -1$. This value decreases when we move away towards outermost regions. This is the first detection of a metallicity gradient in this galaxy. We show that the metallicity gradient is related to an age gradient, in the sense that more metal-rich stars, which are also younger, are concentrated in the central regions of the galaxy.Comment: 30 pages, 13 figures, accepted for publication in Astronomical Journa

Managing the trade-off implications of global supply

The cost versus response trade-off is a growing logistics issue due to many markets being increasingly characterized by demand uncertainty and shorter product life cycles. This is exacerbated further with supply increasingly moving to low cost global sources. However, the poor response implications of global supply are often not addressed or even acknowledged when undertaking such decisions. Consequently, various practical approaches to minimising, postponing or otherwise managing the impact of the demand uncertainty are often only adopted retrospectively. Even though such generic solutions are documented through case examples we lack effective tools and concepts to support the proactive identification and resolution of such trade-offs. This paper reports on case-based theory building research, involving three cases from the UK and USA used in developing a conceptual model with associated tools, in support of such a process

Towards preventing and managing conflict of interest in nutrition policy? An analysis of submissions to a consultation on a draft WHO tool

Background: With multi-stakeholder approaches central to efforts to address global health challenges, debates around conflict of interest (COI) are increasingly prominent. The World Health Organization (WHO) recently developed a proposed tool to support member states in preventing and managing COI in nutrition policy. We analysed responses to an online consultation to explore how actors from across sectors understand COI and the ways in which they use this concept to frame the terms of commercial sector engagement in health governance. Methods: Submissions from 44 Member States, international organisations, non-governmental organizations (NGOs), academic institutions and commercial sector actors were coded using a thematic framework informed by framing theory. Respondents’ orientation to the tool aligned with two broad frames, ie, a ‘collaboration and partnership’ frame that endorsed multi-stakeholder approaches and a ‘restricted engagement’ frame that highlighted core tensions between public health and food industry actors. Results: Responses to the WHO tool reflected contrasting conceptualisations of COI and implications for health governance. While most Member States, NGOs, and academic institutions strongly supported the tool, commercial sector organisations depicted it as inappropriate, unworkable and incompatible with the Sustainable Development Goals (SGDs). Commercial sector respondents advanced a narrow, individual-level understanding of COI, seen as adequately addressed by existing mechanisms for disclosure, and viewed the WHO tool as unduly restricting scope for private sector engagement in nutrition policy. In contrast, health-focused NGOs and several Member States drew on a more expansive understanding of COI that recognised scope for wider tensions between public health goals and commercial interests and associated governance challenges. These submissions mostly welcomed the tool as an innovative approach to preventing and managing such conflicts, although some NGOs sought broader exclusion of corporate actors from policy engagement. Conclusion: Submissions on the WHO tool illustrate how contrasting positions on COI are central to understanding broader debates in nutrition policy and across global health governance. Effective health governance requires greater understanding of how COI can be conceptualised and managed amid high levels of contestation on policy engagement with commercial sector actors. This requires both ongoing innovation in governance tools and more extensive conceptual and empirical research

Increased rate of D1 repair in coral symbionts during bleaching is insufficient to counter accelerated photo-inactivation

We dissect the primary photo-inactivation and the counteracting metabolic repair rates in fragments of the scleractinian coral, Pocillopora damicornis, subjected to a combined stress of a shift to elevated temperature (from 26°C to 32°C) and increased light (from 200 μmol photons m-2 s-1 to 400 μmol photons m-2 s-1) to induce bleaching. During the bleaching treatment the dinoflagellate symbionts showed a 5.5-fold acceleration in their photosystem II (PSII) repair rate constant, demonstrating that they maintain strong metabolic capacity to clear and replace photo-damaged D1 protein at the elevated temperature and light conditions. Nevertheless, the symbionts concurrently suffered a seven-fold increase in the rate constant for PSII photo-inactivation. This rapid photo-inactivation exceeded the PSII repair capacity, therefore tipping the symbionts, and by implication the symbiosis, into net photo-inhibition. Increased photo-inactivation in hospite, rather than an inhibition of PSII repair, is the principle trigger for net photo-inhibition under bleaching conditions. © 2011, by the American Society of Limnology and Oceanography, Inc

Origin of the unusually low nitrogen abundances in young populations of the Large Magellanic Cloud

It is a longstanding problem that HII regions and very young stellar populations in the Large Magellanic Cloud (LMC) have the nitrogen abundances ([N/H]) by a factor of ~7 lower than the solar value. We here discuss a new scenario in which the observed unusually low nitrogen abundances can be closely associated with recent collision and subsequent accretion of HI high velocity clouds (HVCs) that surround the Galaxy and have low nitrogen abundances. We show that if the observed low [N/H] is limited to very young stars with ages less than ~10^7 yr, then the collision/accretion rate of the HVCs onto the LMC needs to be ~ 0.2 M_sun/yr (corresponding to the total HVC mass of 10^6-10^7 M_sun) to dilute the original interstellar medium (ISM) before star formation. The required accretion rate means that even if the typical mass of HVCs accreted onto the LMC is ~ 10^7 M_sun, the Galaxy needs to have ~2500 massive HVCs within the LMC's orbital radius with respect to the Galactic center. The required rather large number of massive HVCs drives us to suggest that the HVCs are not likely to efficiently dilute the ISM of the LMC and consequently lower the [N/H]. We thus suggest the transfer of gas with low [N/H] from the Small Magellanic Cloud (SMC) to the LMC as a promising scenario that can explain the observed low [N/H].Comment: 24pages, 6 figures, accepted in Ap