Non-parametric strong lens inversion of Cl~0024+1654: illustrating the monopole degeneracy

The cluster lens Cl 0024+1654 is undoubtedly one of the most beautiful examples of strong gravitational lensing, providing five large images of a single source with well-resolved substructure. Using the information contained in the positions and the shapes of the images, combined with the null space information, a non-parametric technique is used to infer the strong lensing mass map of the central region of this cluster. This yields a strong lensing mass of 1.60x10^14 M_O within a 0.5' radius around the cluster center. This mass distribution is then used as a case study of the monopole degeneracy, which may be one of the most important degeneracies in gravitational lensing studies and which is extremely hard to break. We illustrate the monopole degeneracy by adding circularly symmetric density distributions with zero total mass to the original mass map of Cl 0024+1654. These redistribute mass in certain areas of the mass map without affecting the observed images in any way. We show that the monopole degeneracy and the mass-sheet degeneracy together lie at the heart of the discrepancies between different gravitational lens reconstructions that can be found in the literature for a given object, and that many images/sources, with an overall high image density in the lens plane, are required to construct an accurate, high-resolution mass map based on strong-lensing data.Comment: 9 pages, accepted for publication by MNRA

Assessing health professionals’ perception of health literacy in Rhode Island community health centers: a qualitative study

Background: Limited health literacy is linked with poor health behaviors, limited health care access, and poor health outcomes. Improving individual and population health outcomes requires understanding and addressing barriers to promoting health literacy. Methods: Using the socio-ecological model as a guiding framework, this qualitative study (Phase 1 of a larger ongoing project) explored the interpersonal and organizational levels that may impact the health literacy levels of patients seeking care at federally qualified community health centers (FQCHCs) in Rhode Island. Focus groups were conducted with FQCHC employees (n = 37) to explore their perceptions of the health literacy skills of their patients, health literacy barriers patients encounter, and possible strategies to increase health literacy. The focus groups were audio-recorded and transcribed, and transcripts were coded using a process of open, axial, and selective coding. Codes were grouped into categories, and the constant comparative approach was used to identify themes. Results: Eight unique themes centered on health literacy, sources of health information, organizational culture’s impact, challenges from limited health literacy, and suggestions to ameliorate the impact of limited health literacy. All focus group participants were versed in health literacy and viewed health literacy as impacting patients’ health status. Participants perceived that some patients at their FQCHC have limited health literacy. Participants spoke of themselves and of their FQCHC addressing health literacy through organizational- and provider-level strategies. They also identified additional strategies (e.g., training staff and providers on health literacy, providing patients with information that includes graphics) that could be adopted or expanded upon to address and promote health literacy. Conclusions: Study findings suggest that strategies may need to be implemented at the organizational-, provider-, and patient- level to advance health literacy. The intervention phase of this project will explore intervention strategies informed by study results, and could include offering health literacy training to providers and staff to increase their understanding of health literacy to include motivation to make and act on healthy decisions and strategies to address health literacy, including the use of visual aids

Brazilian Immigrant Mothers’ Beliefs and Practices Related to Infant Feeding: A Qualitative Study

Background: Exclusive breastfeeding for the first 6 months of life and timely introduction of appropriate solid foods are important determinants of weight status in infancy and later life stages. Disparities in obesity rates among young children suggest that maternal feeding practices during the first 2 years of life may contribute to these disparities. Brazilians are a growing immigrant group in the United States, yet little research has focused on parental beliefs and behaviors affecting the health of Brazilian immigrant children in the United States. Research aim: This study aimed to explore beliefs and infant-feeding practices of Brazilian immigrant mothers in the United States. Methods: Focus group discussions were conducted with Brazilian immigrant mothers. Transcripts were analyzed using thematic analysis and themes categorized using the socioecological model. Results: Twenty-nine immigrant Brazilian mothers participated in the study. Analyses revealed that all participants breastfed their infants. The majority initiated breastfeeding soon after childbirth. However, most mothers did not exclusively breastfeed. They used formula and human milk concomitantly. Family and culture influenced mothers’ infant-feeding beliefs and practices in early introduction of solid foods. Conclusion: As the number of children in the United States growing up in families of immigrant parents increases, understanding influences on Brazilian immigrant mothers’ infant-feeding practices will be important to the development of effective interventions to promote healthy infant feeding and weight status among Brazilian children. Interventions designed for Brazilian immigrant families should incorporate an understanding of social context, family, and cultural factors to develop health promotion messages tailored to the needs of this ethnic group

Global warming potentials and radiative efficiencies of halocarbons and related compounds: a comprehensive review

In the mid-1970s it was recognized that, as well as being substances that deplete stratospheric ozone, chlorofluorocarbons (CFCs) were strong greenhouse gases that could have substantial impacts on radiative forcing of climate change. Around a decade later, this group of radiatively active compounds was expanded to include a large number of replacements for ozone-depleting substances such as chlorocarbons, hydrochlorocarbons, hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), bromofluorocarbons, and bromochlorofluorocarbons. This paper systematically reviews the published literature concerning the radiative efficiencies (REs) of CFCs, bromofluorocarbons and bromochlorofluorocarbons (halons), HCFCs, HFCs, PFCs, SF6, NF3, and related halogen containing compounds. In addition we provide a comprehensive and self-consistent set of new calculations of REs and global warming potentials (GWPs) for these compounds, mostly employing atmospheric lifetimes taken from the available literature. We also present Global Temperature change Potentials (GTPs) for selected gases. Infrared absorption spectra used in the RE calculations were taken from databases and individual studies, and from experimental and ab initio computational studies. Evaluations of REs and GWPs are presented for more than 200 compounds. Our calculations yield REs significantly (> 5%) different from those in the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) for 49 compounds. We present new RE values for more than 100 gases which were not included in AR4. A widely-used simple method to calculate REs and GWPs from absorption spectra and atmospheric lifetimes is assessed and updated. This is the most comprehensive review of the radiative efficiencies and global warming potentials of halogenated compounds performed to date

Superconductivity with hard-core repulsion: BCS-Bose crossover and s-/d-wave competition

We consider fermions on a 2D lattice interacting repulsively on the same site and attractively on the nearest neighbor sites. The model is relevant, for instance, to study the competition between antiferromagnetism and superconductivity in a Kondo lattice. We first solve the two-body problem to show that in the dilute and strong coupling limit the s-wave Bose condensed state is always the ground state. We then consider the many-body problem and treat it at mean-field level by solving exactly the usual gap equation. This guarantees that the superconducting wave-function correctly vanishes when the two fermions (with antiparallel spin) sit on the same site. This fact has important consequences on the superconducting state that are somewhat unusual. In particular this implies a radial node-line for the gap function. When a next neighbor hopping t' is present we find that the s-wave state may develop nodes on the Fermi surface.Comment: 10 pages, 9 fig

Strengthening impact assessment: a call for integration and focus

We suggest that the impact assessment community has lost its way based on our observation that impact assessment is under attack because of a perceived lack of efficiency. Specifically, we contend that the proliferation of different impact assessment types creates separate silos of expertise and feeds arguments for not only a lack of efficiency but also a lack of effectiveness of the process through excessive specialisation and a lack of interdisciplinary practice. We propose that the solution is a return to the basics of impact assessment with a call for increased integration around the goal of sustainable development and focus through better scoping. We rehearse and rebut counter arguments covering silo-based expertise, advocacy, democracy, sustainability understanding and communication. We call on the impact assessment community to rise to the challenge of increasing integration and focus, and to engage in the debate about the means of strengthening impact assessment