On quantum equivalence of dual sigma models: SL(3)SL(3) examples

The equivalence of several $SL(3)$ sigma models and their special Abelian duals is investigated in the two loop order of perturbation theory. The investigation is based on extracting and comparing various $\beta$ functions of the original and dual models. The role of the discrete global symmetries is emphasized.Comment: Plain TEX, 24 page

Comments on the Instanton Size Distribution

By studying the non-linear effects of overlapping instanton pairs we address difficulties in the identification of instanton distributions when the average instanton size is comparable to the average distance. For the exact charge two solution, we study how its parametrisation relates to a description in terms of individual instantons. There exist two dual sets of parameters describing the same charge two instanton solution. This duality implies the existence of a minimal separation between two instantons. Conventionally used lattice instanton finder algorithms based on the assumption of diluteness tend to underestimate instanton sizes. Finally we numerically confirm this for realistic parameters of the instanton liquid. The effect is enhanced by parallel orientation in group space.Comment: LaTeX, 15 pages, 3 figure

Perturbative Quantum (In)equivalence of Dual σ\sigma Models in 22 dimensions

Various examples of target space duality transformations are investigated up to two loop order in perturbation theory. Our results show that when using the tree level (`naive') transformation rules the dual theories are in general {\it inequivalent} at two loops to the original ones, (both for the Abelian and the non Abelian duality).Comment: 11 pages, Latex, uses espcrc2.st

On string cosmology and the RG flow in 2d field theory

Time-dependent solutions of bosonic string theory resemble renormalisation group trajectories in the space of 2d field theories: they often interpolate between repulsive and attractive static solutions. It is shown that the attractive static solutions are those whose spatial sections are minima of |\bar c-25|, where \bar c is the `c-function'. The size of the domain of attraction of such a solution may be a measure of the probability of the corresponding string vacuum. Our discussion has also an implication for the RG flow in theories coupled to dynamical 2d gravity: the flow from models with c>25 to models with c<25 is forbidden.Comment: 16 pages, Latex, BUTP-94/7, Imperial/TP/93-94/29 (some footnotes and references added.

Are the school prevention programmes - aimed at de-normalizing smoking among youths - beneficial in the long term? An example from the Smoke Free Class Competition in Italy

Tobacco smoking by young people is of great concern because it usually leads to regular smoking, nicotine addiction and quitting difficulties. Young people "hooked" by tobacco maintain the profits of the tobacco industry by replacing smokers who quit or die. If new generations could be tobacco-free, as supported by tobacco endgame strategies, the tobacco epidemic could end within decades. Smoking prevention programmes for teens are offered by schools with the aim to prevent or delay smoking onset. Among these, the Smoke Free Class Competition (SFC) was widely implemented in Europe. Its effectiveness yielded conflicting results, but it was only evaluated at short/medium term (6 - 18 months). The aim of this study is to evaluate its effectiveness after a longer follow-up (3 to 5 years) in order to allow enough time for the maturing of the students and the internalization of the experience and its contents. Fifteen classes were randomly sampled from two Italian high schools of Bologna province that regularly offered the SFC to first year students; 382 students (174 participating in the SFC and 208 controls) were retrospectively followed-up and provided their "smoking histories". At the end of their last year of school (after 5 years from the SFC), the percentage of students who stated that they were regular smokers was lower among the SFC students than in controls: 13.5% vs 32.9% (p=0.03). From the students' "smoking histories", statistically significant protective ORs were observed for SFC students at the end of 1st and 5th year: 0.42 (95% CI 0.19-0.93) and 0.32 (95% CI 0.11-0.91) respectively. Absence of smokers in the family was also a strongly statistically significant factor associated with being a non-smoker student. These results suggest that SFC may have a positive impact on lowering the prevalence of smoking in the long term (5 years)

On the Low-Energy Effective Action of N=2 Supersymmetric Yang-Mills Theory

We investigate the perturbative part of Seiberg's low-energy effective action of N=2 supersymmetric Yang-Mills theory in Wess-Zumino gauge in the conventional effective field theory technique. Using the method of constant field approximation and restricting the effective action with at most two derivatives and not more than four-fermion couplings, we show some features of the low-energy effective action given by Seiberg based on $U(1)_R$ anomaly and non-perturbative $\beta$-function arguments.Comment: 27 pages, RevTex, no figure

A new family of SU(2)SU(2) symmetric integrable sigma models

(Minor corrections and reference added)Comment: (ITP Budapest Report No. 502) (11 page

Racial and Ethnic Disparities in Diabetes Complications in the Northeastern United States: The Role of Socioeconomic Status

The role of socioeconomic status (SES) in explaining racial/ethnic disparities in diabetes remains unclear. We investigated disparities in self-reported diabetes complications, and the role of macro (e.g., income, education) and micro (e.g., ‘owning a home’ or ‘having a checking account’) SES indicators in explaining these differences. The sample included individuals with a diagnosis of diabetes (N=795) who were on average 55 years old, and 55.6% non-Hispanic White, 25.0% African American, and 19.4% Hispanic. Approximately 8% reported nephropathy, 35% reported retinopathy, and 16% reported cardiovascular disease. There were significant disparities in the rates of complications among non-Hispanic White, African American and Hispanic participants, with Hispanics having the highest rates of nephropathy, retinopathy, and cardiovascular disease. Macro SES indicators (e.g., income) mediated racial differences (i.e., non-Hispanic Whites vs. African Americans) in self-reported retinopathy, a combination of macro and more micro SES indicators (e.g., education, income, and ‘owning a home’ or ‘having a checking account’) mediated racial/ethnic differences (i.e., non-Hispanic Whites vs. Hispanics) in self-reported cardiovascular disease, and only micro SES indicators (e.g., ‘owning a home’ or ‘having a checking account’) mediated differences between lower income SES racial/ethnic minority groups (i.e., African Americans vs. Hispanics) in self-reported retinopathy and cardiovascular disease. Findings underscore that indicators of SES must be sensitive to the outcome of interest and the racial/ethnic groups being compared

Topological twisting of conformal supercharges

Putting a twisted version of N=4 super Yang-Mills on a curved four-dimensional manifold generically breaks all conformal supersymmetries. In the special case where the four-manifold is a cone, we show that exactly two conformal supercharges remain unbroken. We construct an off-shell formulation of the theory such that the two unbroken conformal supercharges combine into a family of topological charges parameterized by CP^1. The resulting theory is topological in the sense that it is independent of the metric on the three-dimensional base of the cone.Comment: 1+33 pages; references added, an address change

On infinite walls in deformation quantization

We examine the deformation quantization of a single particle moving in one dimension (i) in the presence of an infinite potential wall, (ii) confined by an infinite square well, and (iii) bound by a delta function potential energy. In deformation quantization, considered as an autonomous formulation of quantum mechanics, the Wigner function of stationary states must be found by solving the so-called \*-genvalue (``stargenvalue'') equation for the Hamiltonian. For the cases considered here, this pseudo-differential equation is difficult to solve directly, without an ad hoc modification of the potential. Here we treat the infinite wall as the limit of a solvable exponential potential. Before the limit is taken, the corresponding \*-genvalue equation involves the Wigner function at momenta translated by imaginary amounts. We show that it can be converted to a partial differential equation, however, with a well-defined limit. We demonstrate that the Wigner functions calculated from the standard Schr\"odinger wave functions satisfy the resulting new equation. Finally, we show how our results may be adapted to allow for the presence of another, non-singular part in the potential.Comment: 22 pages, to appear in Annals of Physic