Singular standing-ring solutions of nonlinear partial differential equations

We present a general framework for constructing singular solutions of nonlinear evolution equations that become singular on a d-dimensional sphere, where d>1. The asymptotic profile and blowup rate of these solutions are the same as those of solutions of the corresponding one-dimensional equation that become singular at a point. We provide a detailed numerical investigation of these new singular solutions for the following equations: The nonlinear Schrodinger equation, the biharmonic nonlinear Schrodinger equation, the nonlinear heat equation and the nonlinear biharmonic heat equation.Comment: 34 pages, 21 figure

Nanocomposite Bi/TiO2 multilayer thin flms deposited by a crossed beam laser ablation confguration

Articulo relacionado con la caracterizacion de materialesA crossed beam pulsed laser deposition confguration was used to prepare nanocomposites Bi/TiO2 thin flms on two different substrates. The multilayered system was formed by depositing TiO2 and Bi layers alternately. In order to embed the Bi nanostructures in TiO2, the subsequent TiO2 layers were synthesized using a constant number of laser pulses (3000) corresponding to a thickness of approximately 21 nm. The Bi nanostructures were deposited on the TiO2 layers alternately by irradiating the Bi target with 30, 100, 200, and 300 laser pulses. In this way, the Bi nanostructures were embedded inside the TiO2 matrix. A total of 8 samples with bismuth and one reference, with TiO2 only, were produced. Transmission Electron Microscopy (TEM) showed that nearly spherical nanoparticles (NPs) were obtained at lower number of pulses, whereas at 300 pulses a quasi-percolated nanostructured Bi flm was obtained. X-Ray Photoelectron Spectroscopy (XPS) revealed that the TiO2 layers were not afected due to the bismuth presence. Raman Spectroscopy showed vibrational features characteristic of the rutile phase for the titania layer. The Raman spectrum of the multilayer prepared using 300 laser pulses on the bismuth, suggests that the Bi layer is formed by a mixture of metallic Bi, and α-Bi2O3. The Ultraviolet–Visible Spectroscopy reveals that no substantial changes are presented in the transmittance spectra indicating similar optical properties of the diferent deposits. Finally, the photoluminescence emission spectra indicate that the substrate position in the deposition chamber afects the electronic structure of the material.A. Martínez-Chávez thanks CONACyT for the scholarship granted (No. 815785). K. Esquivel and L. Escobar thank the Engineering Faculty-UAQ for the fnancial support granted through the Attention to national problems fund and the FONDEC-UAQ-2021. We greatly appreciate the collaboration of R. Basurto in performing the XPS measurements

Dependency of the combustion behavior of energy grass and three other types of biomass upon lignocellulosic composition

The combustion characteristics of four kinds of biomass fuels (energy grass, sawdust, corn cob, and walnut shell) are investigated in this article. All the samples are heated from room temperature to 800°C at multiple heating rates of 10, 20, and 30°C/min. The effect of hemicellulose, cellulose, and lignin components on the pyrolysis and combustion processes of energy grass is explored by comparison to those of the other three types of biomass. The hemicellulose and cellulose content of samples could improve the devolatilization performance during biomass combustion. Furthermore, the comprehensive combustion index suggested herein indicates that the combustion performance of energy grass or walnut shell is limited by their high ash content or their low ratio of cellulose to lignin. Kinetic parameters are obtained by combining the isoconversional method (OFW and KAS models) and the method of master-plots. The apparent activation energy of the devolatilization stage is higher than that of the char oxidization stage, which is mainly influenced by the lignocellulosic composition

Cardiovascular health in Brazilian state capitals

Objetivo: estimar a prevalência das métricas de saúde cardiovascular ideal em nível populacional, segundo sexo, idade, escolaridade e região de moradia. Método: estudo transversal que utilizou dados de 41.134 participantes do Sistema de Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico. A avaliação da saúde cardiovascular ideal considerou quatro fatores comportamentais: não fumar; apresentar índice de massa corporal menor do que 25 kg/m2; realizar atividade física; consumir frutas e hortaliças cinco ou mais vezes por dia, e dois fatores clínicos: não referir diagnóstico de diabetes e de hipertensão arterial. A soma dos fatores resultou em um escore que variou de zero (pior saúde cardiovascular) a seis (saúde cardiovascular ideal) fatores em níveis ideais. Resultados: considerando os seis fatores, somente 3,4% da população estudada apresentou níveis ideais de saúde cardiovascular e a maioria dos participantes (57,6%) apresentou três ou quatro fatores ideais. As mulheres apresentaram maior prevalência de saúde cardiovascular ideal (3,8% vs. 2,9% dos homens) (p < 0,0001). Conclusão: os achados deste estudo são condizentes com o elevado risco de mortalidade por doenças cardiovasculares, observado para a população brasileira, e podem contribuir para a melhor compreensão do cenário da saúde cardiovascular na população urbana do país.Objetivo: estimar la prevalencia de los indicadores de salud cardiovascular ideal en el ámbito poblacional, según sexo, edad, escolaridad y región de residencia. Método: estudio transversal que utilizó datos de 41.134 participantes del Sistema de Vigilancia de Factores de Riesgo y Protección para Enfermedades Crónicas por Encuesta Telefónica. La evaluación de la salud cardiovascular ideal consideró cuatro factores comportamentales: no fumar; presentar índice de masa corporal menor que 25 kg/m2; realizar actividad física y consumir frutas y hortalizas cinco o más veces por día; y dos factores clínicos (no referir diagnóstico de diabetes y de hipertensión arterial). La suma de los factores resultó en un puntaje que varió de cero (peor salud cardiovascular) a seis (salud cardiovascular ideal) factores en niveles ideales. Resultados: considerando los seis factores, solamente 3,4% de la población estudiada presentó niveles ideales de salud cardiovascular y la mayoría de los participantes (57,6%) presentó tres o cuatro factores ideales. Las mujeres presentaron mayor prevalencia de salud cardiovascular ideal (3,8% versus 2,9% de los hombres) (p < 0,0001). Conclusión: los hallazgos de este estudio son coherentes con el elevado riesgo de mortalidad por enfermedades cardiovasculares, observado para la población brasileña y pueden contribuir para comprender mejor el escenario de salud cardiovascular en la población urbana del país.Objective: to estimate the prevalence of ideal cardiovascular health indicators in the Brazilian population, according to gender, age, education and region of residence. Method: cross-sectional study that used data from 41,134 participants of the Surveillance System of Risk and Protective Factors for Chronic Diseases by Telephone Survey (Vigitel). The ideal cardiovascular health assessment considers four behavioral factors: not smoking; body mass index less than 25 kg/m2; practicing physical activity, eating fruits and vegetables five or more times per day; and two clinical factors (no diagnosis of diabetes or hypertension). The sum of factors at ideal levels results in a score ranging from zero (worse cardiovascular health) to six (ideal cardiovascular health). Results: considering the six factors, only 3.4% of the studied population presented ideal levels of cardiovascular health, with the majority of participants (57.6%) presenting three or four ideal factors. Women had higher prevalence of ideal cardiovascular health (3.8% versus 2.9% for men) (p < 0.0001). Conclusion: the findings of this study are consistent with the elevated risk of mortality from cardiovascular disease, observed in the Brazilian population. This may contribute to a better understanding of the scenario of cardiovascular health in the urban population of the country

Foros a la carta o difusion de politicas?

Algunas lineas teoricas sobre la resolucion de disputas terriroriales en America Latina a traves de procedimientos judciales y abitraje internacional.Forum shopping or policy diffusion? Different lines of thought on territorial dispute settlement in Latin America through international arbitratin and litigation. In recent years a growing literature on the resolution of territorial disputes vis judicial processes has flourished. Countries willing to setle their maritime and territorial disputes have a plethora or forum options available, including regional and global tribunals. Yet some states seem to prefer global courts over regional tribunals. What explains this choice of forum? The article explores forum selection by analyzing Latin American cases of territorial dispute settlement. Evidence from these cases suggest that forum choice is not all strategic bargaining or institutional design. Rather states seek specific courts influenced by policy diffusion and cognitive biases

Different paths and divergent policies in the UN security system: Brazil and Mexico in comparative perspective

The article of record as published may be found at: http://dx.doi.org/10.1080/13533310903036418How can we explain foreign policy variation among UN member states? Brazil and Mexico are the most likely cases for international primacy in the UN system, given their territorial dimension, demographic tendencies, economic importance, geopolitical location and relative weight in Latin America. Yet, despite their structural similarities, their policies and behavior in the UN system have varied, both in terms of engagement with the Security Council and commitment regarding peacekeeping. By comparing two of Latin America's most influential countries, this study identifies the underlying conditions and mechanisms that explain their incentives to participate in international organizations and their overall international commitment to peace.Approved for public release; distribution is unlimited

Multi-wavelength digital in-line holographic microscopy

The use of multiple wavelength illumination in digital in-line holographic microscopy is presented. A biological sample is illuminated sequentially with three different optical sources and the separate holograms reconstructed with the appropriate wavelength. For controlling the scale of the reconstructed holograms, a reconstruction algorithm that allows for choosing the pixel size at the reconstruction plane independently of the wavelength and the reconstruction distance is used. The method is illustrated with experimental results. © OSA 2012