A class of chiral fermion models

We study the relation between the Roma and Zaragoza proposals for chiral fermions on the lattice. The fermion action in the Roma approach is shown to be equivalent to one of the Zaragoza type. This result is used to perform a mean-field study of the phase diagram for chiral Yukawa models based on the Roma action. The phase diagram is compared with the one based on the Zaragoza model with the most local choice for the fermion interactions.Comment: Version to appear in Nucl. Phys. B. Some general discussion added to the Introduction and Conclusion sections. Now 33 pages Latex; style files and (unchanged) PostScript figures again attached in uufiles forma

Wealth and inequality gradients for the detection and control of hypertension in older individuals in middle-income economies around 2007-2015

Socioeconomic inequalities in the detection and treatment of non-communicable diseases represent a challenge for healthcare systems in middle-income countries (MICs) in the context of population ageing. This challenge is particularly pressing regarding hypertension due to its increasing prevalence among older individuals in MICs, especially among those with lower socioeconomic status (SES). Using comparative data for China, Colombia, Ghana, India, Mexico, Russia and South Africa, we systematically assess the association between SES, measured in the form of a wealth index, and hypertension detection and control around the years 2007-15. Furthermore, we determine what observable factors, such as socio-demographic and health characteristics, explain existing SES-related inequalities in hypertension detection and control using a Blinder-Oaxaca decomposition. Results show that the prevalence of undetected hypertension is significantly associated with lower SES. For uncontrolled hypertension, there is evidence of a significant gradient in three of the six countries at the time the data were collected. Differences between rural and urban areas as well as lower and higher educated individuals account for the largest proportion of SES-inequalities in hypertension detection and control at the time. Improved access to primary healthcare in MICs since then may have contributed to a reduction in health inequalities in detection and treatment of hypertension. However, whether this indeed has been the case remains to be investigated

Behavioural response to a sudden health risk: Dengue and educational outcomes in Colombia

Epidemics tend to have a debilitating influence on the lives of directly afflicted families. However, the presence of an epidemic can also change the behaviour and outcomes of those not directly affected. This paper makes use of a short, sharp, unexpected epidemic to examine the behavioural response of the general public to a sudden shift in the perceived risk to an individual's health and mortality. Our analysis finds that unafflicted school students change their behaviour substantially, affecting important life outcomes. In particular, we find that close to 4 fewer students, out of a typical class of 47 pupils, sit their school leaving examination for every additional 10 cases of severe Dengue per 10 000 inhabitants in a municipality. We rule out several possible mechanisms, leaving an increase in the salience of the disease's risks as a plausible explanation for our findings

Large scale emergent properties of an autocatalytic reaction-diffusion model subject to noise

The non-equilibrium dynamic fluctuations of a stochastic version of the Gray-Scott (GS) model are studied analytically in leading order in perturbation theory by means of the dynamic renormalization group. There is an attracting stable fixed point at one-loop order, and the asymptotic scaling of the correlation functions is predicted for both spatial and temporally correlated noise sources. New effective three-body reaction terms, not present in the original GS model, are induced by the combined interplay of the fluctuations and nonlinearities.Comment: 13 pages, 2 figure

Food Changes and Geography: Dietary Transition in Colombia

Background: The food transition can no longer be studied in developed countries because the so-called Western diet now predominates in these areas. However, in developing countries, it is still possible to study the food transition. It is a novel concept that complements other transitions such as the demographic, economic, nutritional and epidemiological transitions. Objectives: The objectives of this study were to a) estimate the average departmental adherence to the three pre-established food patterns, b) assess adherence patterns based on the Global Spatial Analysis, c) evaluate whether the Local Spatial Variations in the adherence to food patterns are random or follow defined patterns (cluster) and d) generate 2D maps to graphically locate the food patterns that compose the phenomenon of the food transition occurring in Colombia. Methods: The National Survey of the Nutritional Situation in Colombia, 2010 was analyzed. Based on factor analysis, three consumption patterns were established; Protein/Fiber, Snack and Snack and Traditional/Starch and the average departmental adhesion was estimated. The global and local spatial variation was calculated with the Moran indexes. Findings: the average adherence to the traditional consumption/starch pattern was –0.00 (95% CI: –0.12 to 0.12). The mean adherence to the protein/fiber intake pattern was –0.07 (95% CI: –0.16 to 0.03). The average adherence to the pattern of snack consumption was –0.03 (95% CI: –0.11 to 0.05). The three patterns of food consumption values for the Global Total Moran Index, for men and women were positive and statistically significant. Conclusions: The food transition experienced by Colombia is not homogeneous and there are well defined clusters for adherence in the three predefined food patterns. Within the clusters there are differences by sex. In regions where the traditional pattern/starch predominates, the presence of the snack pattern is very weak

Phase Diagram of a Lattice SU(2)×SU(2)SU(2) \times SU(2) Scalar-Fermion Model Using the Zaragoza Fermions

We present a calculation of the phase diagram of a $SU(2) \times SU(2)$ chiral Yukawa model with massless decoupled doublers, using a saddle point approach, both for small and large Yukawa coupling. Some preliminary MonteCarlo results are also shown.Comment: 3 pages + 2 figs.; Ref. DFTUZ 93/18, Lattice'93 tal

Massless Decoupled Doublers: Chiral Yukawa Models and Chiral Gauge Theories

We present a new method for regularizing chiral theories on the lattice. The arbitrariness in the regularization is used in order to decouple massless replica fermions. A continuum limit with only one fermion is obtained in perturbation theory and a Golterman-Petcher like symmetry related to the decoupling of the replicas in the non-perturbative regime is identified. In the case of Chiral Gauge Theories gauge invariance is broken at the level of the regularization, so our approach shares many of the characteristics of the Rome approach.Comment: 11 page