Dynamics of the Distorted Diamond Chain

We present results on the dynamics of the distorted diamond chain, S=1/2 dimers alternating with single spins 1/2 and exchange couplings $J_1$ and $J_3$ in between. The dynamics in the spin fluid (SF) and tetramer-dimer (TD) phases is investigated numerically by exact diagonalisation for up to 24 spins. Representative excitation spectra are presented, both for zero magnetic field and in the 1/3 plateau phase and the relevant parameters are determined across the phase diagram. The behavior across the SF-TD phase transition line is discussed for the specific heat and for excitation spectra. The relevance of the distorted diamond chain model for the material Cu$_3$(CO$_3$)$_2$(OH)$_2$ (azurite) is discussed with particular emphasis on inelastic neutron scattering experiments, a recent suggestion of one possibly ferromagnetic coupling constant is not confirmed.Comment: 24 pages, 8 figure

Finite Temperature Dynamics of the Spin 1/2 Bond Alternating Heisenberg Antiferromagnetic Chain

We present results for the dynamic structure factor of the S=1/2 bond alternating Heisenberg chain over a large range of frequencies and temperatures. Data are obtained from a numerical evaluation of thermal averages based on the calculation of all eigenvalues and eigenfunctions for chains of up to 20 spins. Interpretation is guided by the exact temperature dependence in the noninteracting dimer limit which remains qualitatively valid up to an interdimer exchange $\lambda \approx 0.5$. The temperature induced central peak around zero frequency is clearly identified and aspects of the crossover to spin diffusion in its variation from low to high temperatures are discussed. The one-magnon peak acquires an asymmetric shape with increasing temperature. The two-magnon peak is dominated by the S=1 bound state which remains well defined up to temperatures of the order of J. The variation with temperature and wavevector of the integrated intensity for one and two magnon scattering and of the central peak are discussed.Comment: 8 pages, 8 figure

Religious Vehicle Stickers in Nigeria: a discourse of identity, faith and social vision

This study focuses on analysing the ways in which vehicle stickers construct individual and group identities, people’s religious faith and social vision in the context of religious assumptions and practices in Nigeria. Data comprise 73 vehicle stickers collected in Lagos and Ota, between 2006 and 2007 and are analysed within the framework of the post-structuralist model of discourse analysis which views discourse as a product of a complex system of social and institutional practices that sustain its continuous existence (Derrida, 1982; Fairclough, 1989, 1992, 1995; Foucault, 1972, 1981). Results show that through stickers people define their individual and group identities within religious institutional practices. And as a means of group identification, they guarantee social security and privileges. In constructing social vision the stickers help mould the individual aspiration about a future which transcends the present. Significantly, stickers in the data also reveal the tension between Islam and Christianity and the struggle to propagate one above the other. KEY WORDS: assumption, discourse, discursive, practices, religion, stickers

Multiple Rotations of Gaussian Quadratures: An Efficient Method for Uncertainty Analyses in Large-Scale Simulation Models

Concerns regarding the impact of climate change, food price volatility, and weather uncertainty have motivated users of simulation models to consider uncertainty in their simulations. One way to do this is to integrate uncertainty components in the model equations, thus turning the model into a problem of numerical integration. Most of these problems do not have analytical solutions, and researchers, therefore, apply numerical approximation methods. This article presents a novel approach to conducting an uncertainty analysis as an alternative to the computationally burdensome Monte Carlo-based (MC) methods. The developed method is based on the degree three Gaussian quadrature (GQ) formulae and is tested using three large-scale simulation models. While a standard single GQ method often produces low-quality approximations, the results of this study demonstrate that the proposed approach reduces the approximation errors by a factor of nine using only 3.4% of the computational effort required by the MC-based methods in the most computationally demanding model

Beyond a Dichotomy of Perspectives: Understanding Religion on the Basis of Paul Natorp’s Logic of Boundary

Based on Paul Natorp’s (1854–1924) late post-Neo-Kantian “Logic of Boundary” (German: “Grenzlogik”) I will offer a methodically controlled, non-reductionist and equally anti-essentialist reconstruction of the notion of religion. The pre-eminent objective of this reconstructive work is to overcome the well-known epistemological as well as methodological problem of a dichotomy between inside and outside perspectives on the subject of religion. Differently put, the objective consists in an attempt to demonstrate that there actually is “reason in religion” that is intellectually accessible for academic knowledge production. Following Natorp’s splendid formulation I will argue that religion operates neither ‘within’ nor ‘beyond’ the ‘boundary of humanity’ but exactly on [or ‘in’] this boundary. More precisely, I will explicate that religious praxis (including its specific production of knowledge) from Natorp’s standpoint can be understood as the performative realization, and habitual embodiment of the (contextually concrete) boundary of humanity or human reason itself. Due to its principial self-referentiality this boundary carries the crucial sense of a first and last positive and, therefore, both in theoretical terms definitive and in practical terms eminently instructive notion of boundary with no outside. This paradoxically all-enclosing, positive boundary, while explicitly including life’s inevitable negativity but, nonetheless, able to ideally sublate it, is the reason why the practice of religion, as empirical evidence unmistakably documents, can provide an incommensurably fulfilling, significant and meaningful closure with regards to the innermost self-perception of its practitioners (concerning their self-determination or agency)

Design and methods for a randomized clinical trial comparing three outreach efforts to improve screening mammography adherence

<p>Abstract</p> <p>Background</p> <p>Despite the demonstrated need to increase screening mammography utilization and strong evidence that mail and telephone outreach to women can increase screening, most managed care organizations have not adopted comprehensive outreach programs. The uncertainty about optimum strategies and cost effectiveness have retarded widespread acceptance. While 70% of women report getting a mammogram within the prior 2 years, repeat mammography rates are less than 50%. This 5-year study is conducted though a Central Massachusetts healthcare plan and affiliated clinic. All womenhave adequate health insurance to cover the test.</p> <p>Methods/Design</p> <p>This randomized study compares 3 arms: reminder letter alone; reminder letter plus reminder call; reminder letter plus a second reminder and booklet plus a counselor call. All calls provide women with the opportunity to schedule a mammogram in a reasonable time. The invention period will span 4 years and include repeat attempts. The counselor arm is designed to educate, motivate and counsel women in an effort to alleviate PCP burden.</p> <p>All women who have been in the healthcare plan for 24 months and who have a current primary care provider (PCP) and who are aged 51-84 are randomized to 1 of 3 arms. Interventions are limited to women who become ≥18 months from a prior mammogram. Women and their physicians may opt out of the intervention study.</p> <p>Measurement of completed mammograms will use plan billing records and clinic electronic records. The primary outcome is the proportion of women continuously enrolled for ≥24 months who have had ≥1 mammogram in the last 24 months. Secondary outcomes include the number of women who need repeat interventions. The cost effectiveness analysis will measure all costs from the provider perspective.</p> <p>Discussion</p> <p>So far, 18,509 women aged 51-84 have been enrolled into our tracking database and were randomized into one of three arms. At baseline, 5,223 women were eligible for an intervention. We anticipate that the outcome will provide firm data about the maximal effectiveness as well as the cost effectiveness of the interventions both for increasing the mammography rate and the repeat mammography rate.</p> <p>Trial registration</p> <p><url>http://clinicaltrials.gov/</url><a href="http://www.clinicaltrials.gov/ct2/show/NCT01332032">NCT01332032</a></p

Disparities in appendicitis rupture rate among mentally ill patients

<p>Abstract</p> <p>Background</p> <p>Many studies have been carried out that focus on mental patients' access to care for their mental illness, but very few pay attention on these same patients' access to care for their physical diseases. Acute appendicitis is a common surgical emergency. Our population-based study was to test for any possible association between mental illness and perforated appendicitis. We hypothesized that there are significant disparities in access to timely surgical care between appendicitis patients with and without mental illness, and more specifically, between patients with schizophrenia and those with another major mental illness.</p> <p>Methods</p> <p>Using the National Health Insurance (NHI) hospital-discharge data, we compared the likelihood of perforated appendix among 97,589 adults aged 15 and over who were hospitalized for acute appendicitis in Taiwan between the years 1997 to 2001. Among all the patients admitted for appendicitis, the outcome measure was the odds of appendiceal rupture vs. appendicitis that did not result in a ruptured appendix.</p> <p>Results</p> <p>After adjusting for age, gender, ethnicity, socioeconomic status (SES) and hospital characteristics, the presence of schizophrenia was associated with a 2.83 times higher risk of having a ruptured appendix (odds ratio [OR], 2.83; 95% confidence interval [CI], 2.20–3.64). However, the presence of affective psychoses (OR, 1.15; 95% CI: 0.77–1.73) or other mental disorders (OR, 1.58; 95% CI: 0.89–2.81) was not a significant predictor for a ruptured appendix.</p> <p>Conclusion</p> <p>These findings suggest that given the fact that the NHI program reduces financial barriers to care for mentally ill patients, they are still at a disadvantage for obtaining timely treatment for their physical diseases. Of patients with a major mental illness, schizophrenic patients may be the most vulnerable ones for obtaining timely surgical care.</p