Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Modification techniques for asphalt binders, polymers, fillers, fibers, and recently nanomaterialshave been used to improve the performance of asphalt mixtures. This study evaluated the effect ofincorporating pure clay nanoparticles, modified by stearyl dimethyl ammonium chloride(Praepagen WB) and cetyl trimethyl ammonium chloride (Genamin) in the contents of 2, 3, 4, and5% to petroleum asphalt cement with 50/70 degrees of penetration. Physical and rheological testsanalyzed the binders: penetration, softening point, rotational viscosity, degree of performance;these tests were performed before and after the short-term aging procedure and the creep andrecovery under multiple stress procedures. The results showed that these modifiers increased thesoftening point and viscosity, decreased penetration and improved permanent deformation. Thecontents used in this research did not show a significant increase in mixing temperatures. Inaddition, the modifiers showed antioxidant properties. Overall, the organophilic MontmorilloniteWB had the best results in the tests performed. It was concluded that the use of Montmorillonite asa modifier of the asphalt binder is an effective method to improve the properties of the binder.

View factor calculation is a key point in the radiation heat transfer between surfaces. In engineeringit is required to compute the view factor between complex geometries, which include variousperpendicular and inclined surfaces. Currently there are no analytical expressions available for thispurpose, so the use of summation and reciprocity rules (SR) is required, but when complexgeometries are analyzed, handling SR is extremely laborious. Therefore, this work aims to developan equation for the view factor calculation in radiative heat transfer of two arbitrary inclined orparallel rectangular surfaces, by means of the benefits provided by vector calculus. The exactsolutions obtained with contour integration were compared with the values calculated from algebrafactor (AF) using the Hottel's and Hamilton-Morgan's solution and with the results computed fromthe numerical integration of the quadruple integral using Simpson's rule 1/3 with five intervals. Thelack of similar precedents in the technical literature reinforces the practical and scientific nature ofthe proposed method of analysis.

Geographic Information Systems now are used in a great number of branches, like theadministration of resources, the administration of assets, the urban planning, the marketing and thelogistics. This is due to the wide variety of facilities that they offer in the work with space datageographically indexed. On the other hand, the simulation techniques are used in processes where itis necessary to have a previous knowledge of how they will be developed once in March, processeslike the planning of transport, the placement of traffic lights and the location of services stations areamong the commonly feigned phenomenon. This work understands the study of two cases thatintegrate both technologies to achieve good results in the planning of processes. A first case ispresented that understands the configuration and evaluation of the working of traffic signals. Thesecond case is an analysis of the behavior of the patrol car stations located according to a solutiongiven for the maximum covering problem. In both cases, it is evidenced as the use of geographicinformation systems in the simulation can contribute to get more real and useful results for theentities that develop these planning processes.

Introduction: Diffuse interstitial lung disease is a group of diseases that cause a disorder of aerobic capacity and quality of life; in addition, they cause a high rate of morbidity and mortality for this population. The use of home oxygen therapy greater than 15 hours a day has benefits in chronic hypoxemic patients, however, little has been compared to patients who do not receive it.Objective: Describe the clinical characteristics, functional aerobic capacity and health-related quality of life of two groups of patients with diffuse interstitial lung disease, one with indication for home oxygen therapy and another group without indication.Methods: A cross-sectional descriptive study included 41 patients with diffuse interstitial lung disease who signed informed consent. In both groups, demographic and clinical characteristics, anxiety/depression, health quality of life related with the Saint George questionnaire, and functional aerobic capacity with the six-minute gait test were measured. The groups were compared with the student's t-test for independent samples.Results: The diffuse interstitial lung disease group with home oxygen therapy presented a higher percentage of smoking history (p = 0.041), a shorter distance walked in the six-minute gait test (304.1 ± 108.7 vs. 390.3 ± 95.6 p = 0.01), and a lower percentage of the predicted distance (58.37 ± 20.45 vs. 73.34 ± 22.90,    p = 0.034) compared to the diffuse interstitial lung disease group without home oxygen therapy.Conclusions: Patients with diffuse interstitial lung disease with indication of home oxygen therapy have lower functional aerobic capacity compared to patients without indication.

Introduction: Hypertension in childhood is an important health problem due to the frequency with which it occurs today, unlike what happened in past decades. In hypertension it has been found that the antioxidant system is diminished.  Objective: To evaluate the endogenous antioxidant system through the levels of superoxide dismutase, catalase and reduced glutathione in normotensive, prehypertensive and hypertensive children according to sex and skin color. Methods: 308 children participated in this study. Superoxide dismutase was determined by Marklund's method, catalase by Aebi's method, and glutathione reduced by Sedlak's method. A p < 0.05 was used for the significant difference between the groups studied. All tests that were used belong to the SPSS 21.0 package. Results: In the total group, hypertensive boys were found to have a significant decrease in superoxide dismutase and catalase. In hypertensive girls, a significant decrease in superoxide dismutase and reduced glutathione was found in prehypertensive. Superoxide dismutase had a significant decrease in prehypertensive and hypertensive white-skinned children as did catalase in hypertensive children. The combined study of skin color and sex showed that prehypertensive and hypertensive girls with white skin had a significant decrease in superoxide dismutase and reduced glutathione.Conclusions: The antioxidant system in children´s hypertension is altered, with superoxide dismutase being the most affected antioxidant.

Introduction: The COVID-19 pandemic has had serious consequences for the mental health of individuals, especially health care providers, who have experienced symptoms of stress, anxiety and depression that affect their personal, family and social lives. This situation has led health entities to evaluate the negative effects and to design interventions.Objective: To establish the relationship between burnout syndrome, anxiety, depression and work well-being, considering sociodemographic and work variables, including differences according to the type of work.Methods: The present study is non-causal, comparative, cross-sectional and prospective. The sampling was intentional non-probabilistic, with a total of 366 participants from three hospitals in Ancash (Peru) under COVID-19 conditions during the second wave. For the measurement of the variables, the Maslach Burnout Inventory, the Goldberg anxiety/depression subscales and the Sánchez-Cánovas work well-being subscales were used.Results: The results indicated multiple relationships among burnout syndrome, anxiety, depression and work well-being (p <0.05). Likewise, these relationships were also presented considering some sociodemographic and labor variables (p <0.05).Conclusions: The variables studied have a significant relationship in the health care personnel examined. Based on these findings, it is possible to have a baseline of the mental health of health personnel to plan interventions that emphasize those variables and groups at risk that require special attention.

En el presente trabajo se describe un caso de muerte súbita en una mujer de 70 años que fallece 20 días después de ser dada de alta tras ingreso por infección urinaria secundaria a litiasis renal complicada con shock séptico e insuficiencia renal y respiratoria. En el corazón se identificó una cardiopatía isquémica crónica y extensas áreas de miocardio calcificado. Además, se exponen los tipos de calcificaciones del miocardio existentes y sus causas; y se analizan aquellos factores que en el caso presentado han podido causar la calcificación del miocardio.

Introduction: The evolution of methodological paradigms underpins mathematical models and their applications in different fields of science, in particular, medical sciences. Objective: To solve medical problems according to the evolution and approaches of methodological paradigms.Methods: Theoretical methods are used: analysis and synthesis, induction and deduction, abstraction and concretion, and the logical historical method. Construction of curves of functions and their reasons for change. Mathematical methods, procedures and algorithms are applied, as well as the approaches of clinical and epidemiological methods.Analysis and integration of information: Medical problems are solved according to the evolution and approaches of methodological paradigms, through mathematical models of quantitative and qualitative prediction, comparative analysis facilitates the understanding, explanation and interpretation of the information represented, from the behavior of the phenomena and / or processes under study. Conclusions: The resolution of medical problems through the application of mathematical models of quantitative and qualitative prediction, which describe the continuous, discontinuous (jumping) and stochastic behaviors, constitute alternatives to adopt decisions and verify treatments in patients, from the clinical and epidemiological approaches. These same models are useful in solving the training aspects of future specialists.

Introduction: Colombian university students show low reading levels. This problem is caused in part by inadequate government policies to promote reading and affects the results of Saber Pro tests.Objective: Establish the association between academic performance and weekly academic reading time of a sample of university students of Physical Culture, Sports and Recreation.Methods: Cross-sectional analytical study conducted in 149 students enrolled in the period 2018-II. Descriptive, bivariate and multiple analyses were performed using logistic regression models. To establish the reading time, an ad hoc questionnaire was applied. In the case of academic performance, the accumulated grades average of the university’s Academic System was consulted.  Results: The median cumulative grades average of the participants was 3.90/5.0, IR: 0.5 (women: 4.15; RI: 0.35; men: 3.9; RI: 0.4; p = 0.0038). The median weekly reading was 60 minutes RI: 150 (women: 122.5; RI: 120; men: 60, RI: 160; p = 0.0139). After adjusting by sex, age and socioeconomic status, having an average above 3.9/5.0 was associated with more weekly reading minutes (OR: 1.004, 95% CI: 1.001 – 1.007, p = 0.007). Conclusions: Women have more weekly reading time and better academic average than men. Students who have more weekly reading minutes are more likely to have a cumulative average greater than or equal to 3.9 out of 5.0.

Introduction: Solid pancreatic lesions represent a diagnostic and therapeutic challenge, being endoscopic ultrasound elastography a technique in development.Objective: To describe the use of endoscopic ultrasound elastography in the diagnosis of solid lesions of the pancreas.Methods: A bibliographic review was conducted on the use of endoscopic ultrasound elastography in solid lesions of the pancreas using databases (PubMed, Medline, SciELO, LILACS and Elsevier). Information from national and international sites was used. The quality and validity of the selected articles were analyzed.Development: The utility and characteristics of endoscopic ultrasound elastography in the diagnosis of solid lesions of the pancreas and its importance as a complementary tool are described.Conclusions: Endoscopic ultrasound elastography is a novel imaging technique that allows a better approach to characterizing solid lesions of the pancreas.