Single-hole properties in the tt-JJ and strong-coupling models

We report numerical results for the single-hole properties in the $t$-$J$ model and the strong-coupling approximation to the Hubbard model in two dimensions. Using the hopping basis with over $10^6$ states we discuss (for an infinite system) the bandwidth, the leading Fourier coefficients in the dispersion, the band masses, and the spin-spin correlations near the hole. We compare our results with those obtained by other methods. The band minimum is found to be at ($\pi/2,\pi/2$) for the $t$-$J$ model for $0.1 \leq t/J \leq 10$, and for the strong-coupling model for $1 \leq t/J \leq 10$. The bandwidth in both models is approximately $2J$ at large $t/J$, in rough agreement with loop-expansion results but in disagreement with other results. The strong-coupling bandwidth for t/J\agt6 can be obtained from the $t$-$J$ model by treating the three-site terms in first-order perturbation theory. The dispersion along the magnetic zone face is flat, giving a large parallel/perpendicular band mass ratio.Comment: 1 RevTeX file with epsf directives to include 8 .eps figures 8 figure files encoded using uufile

Risk communication and informed consent in the medical tourism industry: A thematic content analysis of canadian broker websites

<p>Abstract</p> <p>Background</p> <p>Medical tourism, thought of as patients seeking non-emergency medical care outside of their home countries, is a growing industry worldwide. Canadians are amongst those engaging in medical tourism, and many are helped in the process of accessing care abroad by medical tourism brokers - agents who specialize in making international medical care arrangements for patients. As a key source of information for these patients, brokers are likely to play an important role in communicating the risks and benefits of undergoing surgery or other procedures abroad to their clientele. This raises important ethical concerns regarding processes such as informed consent and the liability of brokers in the event that complications arise from procedures. The purpose of this article is to examine the language, information, and online marketing of Canadian medical tourism brokers' websites in light of such ethical concerns.</p> <p>Methods</p> <p>An exhaustive online search using multiple search engines and keywords was performed to compile a comprehensive directory of English-language Canadian medical tourism brokerage websites. These websites were examined using thematic content analysis, which included identifying informational themes, generating frequency counts of these themes, and comparing trends in these counts to the established literature.</p> <p>Results</p> <p>Seventeen websites were identified for inclusion in this study. It was found that Canadian medical tourism broker websites varied widely in scope, content, professionalism and depth of information. Three themes emerged from the thematic content analysis: training and accreditation, risk communication, and business dimensions. Third party accreditation bodies of debatable regulatory value were regularly mentioned on the reviewed websites, and discussion of surgical risk was absent on 47% of the websites reviewed, with limited discussion of risk on the remaining ones. Terminology describing brokers' roles was somewhat inconsistent across the websites. Finally, brokers' roles in follow up care, their prices, and the speed of surgery were the most commonly included business dimensions on the reviewed websites.</p> <p>Conclusion</p> <p>Canadian medical tourism brokers currently lack a common standard of care and accreditation, and are widely lacking in providing adequate risk communication for potential medical tourists. This has implications for the informed consent and consequent safety of Canadian medical tourists.</p

Increasing vegetable intakes: rationale and systematic review of published interventions

Purpose While the health benefits of a high fruit and vegetable consumption are well known and considerable work has attempted to improve intakes, increasing evidence also recognises a distinction between fruit and vegetables, both in their impacts on health and in consumption patterns. Increasing work suggests health benefits from a high consumption specifically of vegetables, yet intakes remain low, and barriers to increasing intakes are prevalent making intervention difficult. A systematic review was undertaken to identify from the published literature all studies reporting an intervention to increase intakes of vegetables as a distinct food group. Methods Databases—PubMed, PsychInfo and Medline—were searched over all years of records until April 2015 using pre-specified terms. Results Our searches identified 77 studies, detailing 140 interventions, of which 133 (81 %) interventions were conducted in children. Interventions aimed to use or change hedonic factors, such as taste, liking and familiarity (n = 72), use or change environmental factors (n = 39), use or change cognitive factors (n = 19), or a combination of strategies (n = 10). Increased vegetable acceptance, selection and/or consumption were reported to some degree in 116 (83 %) interventions, but the majority of effects seem small and inconsistent. Conclusions Greater percent success is currently found from environmental, educational and multi-component interventions, but publication bias is likely, and long-term effects and cost-effectiveness are rarely considered. A focus on long-term benefits and sustained behaviour change is required. Certain population groups are also noticeably absent from the current list of tried interventions