Asymptotic expansions are obtained for the solution of the (2+1)-dimensional nonstationary Dirac equation describing the wave function of a massive fermion in graphene, placed in an external ...inhomogeneous electric and magnetic field. The semiclassical asymptotics of the solution of the Cauchy problem for this equation with rapidly oscillating and rapidly decreasing initial data are found. This made it possible to find quasiphotons asymptotic solutions describing Gaussian wave packets concentrated near a point running along a semiclassical trajectory.
An integral representation of solutions of the wave equation obtained earlier is studied. The integrand contains weighted localized solutions of the wave equation that depend on parameters, which are ...variables of integration. Dependent on parameters, a family of localized solutions is constructed from one solution by means of transformations of shift, scaling, and the Lorentz transform. Sufficient conditions are derived, which ensure the pointwise convergence of the obtained improper integral in the space of parameters. The convergence of this integral in ℒ
2
norm is proved as well. Bibliography: 22 titles.
The objective of this study was to identify Brazil's most critical garbage codes (GCs) reclassified to Chagas disease (ChD) in mortality data and their proportions. We also estimated the potential ...impact of misclassification on the number of deaths attributed to ChD.
Population-based descriptive study.
We used the Mortality Information System (SIM; in Portuguese) data before and after routine GC investigation in 2015–2019 to evaluate ChD deaths detected among them. We identified priority GCs, which contributed more than 0.1 % to the percentage of total ChD deaths registered. Spearman's correlation was used to evaluate the association between the reclassification of priority GCs and ChD prevalence. Then, we applied the GC correction factors to estimate the number of deaths attributed to ChD.
22,154 deaths were reported as ChD in the study period. Among them, 1004 deaths originally listed as priority GCs were deaths reclassified to ChD after an investigation in the SIM final database. Unspecific cardiomyopathy (10.2 %), unspecific heart diseases (4.7 %), and heart failure (2.8 %) were GCs with the highest proportions of reclassification to ChD in Brazil. Higher ChD prevalence at the state level was associated with a higher proportion of GC deaths reclassified as ChD. When applying correction factors identified after investigation, we estimated an increase of 26.4 % in registered ChD deaths, mostly in states with higher endemicity.
GCs might conceal deaths due to ChD, particularly in Brazil's states with higher endemicity. The approach suggested in this study may offer an alternative method for estimating ChD-related deaths in endemic countries.
Background: Cut points for defining obesity have been derived from mortality data among Whites from Europe and the United States and their accuracy to screen for high risk of coronary heart disease ...(CHD) in other ethnic groups has been questioned. Objective: To compare the accuracy and to define ethnic and gender-specific optimal cut points for body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) when they are used in screening for high risk of CHD in the Latin-American and the US populations. Methods: We estimated the accuracy and optimal cut points for BMI, WC and WHR to screen for CHD risk in Latin Americans (n=18 976), non-Hispanic Whites (Whites; n=8956), non-Hispanic Blacks (Blacks; n=5205) and Hispanics (n=5803). High risk of CHD was defined as a 10-year risk approximately equal to 20% (Framingham equation). The area under the receiver operator characteristic curve (AUC) and the misclassification-cost term were used to assess accuracy and to identify optimal cut points. Results: WHR had the highest AUC in all ethnic groups (from 0.75 to 0.82) and BMI had the lowest (from 0.50 to 0.59). Optimal cut point for BMI was similar across ethnic/gender groups (27 kg/m2). In women, cut points for WC (94 cm) and WHR (0.91) were consistent by ethnicity. In men, cut points for WC and WHR varied significantly with ethnicity: from 91 cm in Latin Americans to 102 cm in Whites, and from 0.94 in Latin Americans to 0.99 in Hispanics, respectively. Conclusion: WHR is the most accurate anthropometric indicator to screen for high risk of CHD, whereas BMI is almost uninformative. The same BMI cut point should be used in all men and women. Unique cut points for WC and WHR should be used in all women, but ethnic-specific cut points seem warranted among men.
Decompositions of solutions of the wave equation in terms of localized solutions from the wide class of the same equation are constructed by means of the affine Poincaré continuous wavelet analysis. ...Two particular decompositions are considered. One of them is represented in terms of nonstationary particle-like solutions, the Gaussian wave packets. The another one is a decomposition of a monochromatic field in terms of monochromatic Gaussian beams. A comparison with known results is given.
Current, high-quality data are needed to evaluate the health impact of the epidemic of obesity in Latin America. The Latin American Consortium of Studies of Obesity (LASO) has been established, with ...the objectives of (i) Accurately estimating the prevalence of obesity and its distribution by sociodemographic characteristics; (ii) Identifying ethnic, socioeconomic and behavioural determinants of obesity; (iii) Estimating the association between various anthropometric indicators or obesity and major cardiovascular risk factors and (iv) Quantifying the validity of standard definitions of the various indexes of obesity in Latin American population. To achieve these objectives, LASO makes use of individual data from existing studies. To date, the LASO consortium includes data from 11 studies from eight countries (Argentina, Chile, Colombia, Costa Rica, Dominican Republic, Peru, Puerto Rico and Venezuela), including a total of 32 462 subjects. This article describes the overall organization of LASO, the individual studies involved and the overall strategy for data analysis. LASO will foster the development of collaborative obesity research among Latin American investigators. More important, results from LASO will be instrumental to inform health policies aiming to curtail the epidemic of obesity in the region.
Transverse electromagnetic electric (TE) and transverse magnetic (TM) creeping waves on a surface with an anisotropic impedance boundary condition are considered. An asymptotic theory is developed ...for creeping waves. The theory is valid near the line where the attenuation parameters of two different types of waves coincide and, therefore, standard asymptotics are inapplicable. Asymptotic formulas describing physical effects that occur when a creeping wave propagates across the degeneracy line are derived. It is found that, behind the degeneracy line, a propagating TE wave excites a TM wave with a small amplitude (of order
O
(
k
−1/6
)) and a propagating TM wave excites a TE wave.
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