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Population-wide vaccination is the most promising long-term COVID-19 disease management strategy. However, the protection offered by the currently available COVID-19 vaccines wanes over time, requiring boosters to be periodically given, which represents an unattainable challenge, especially if it is necessary to apply several doses per year. Therefore, it is essential to design strategies that contribute to maximizing the control of the pandemic with the available vaccines. Achieving this objective requires knowing, as precisely and accurately as possible, the changes in vaccine effectiveness over time in each population group, considering the eventual dependence on age, sex, etc. Thus, the present work proposes a novel approach to calculating realistic effectiveness profiles against symptomatic disease. In addition, this strategy can be adapted to estimate realistic effectiveness profiles against hospitalizations or deaths. All such time-dependent profiles allow the design of improved vaccination schedules, where each dose can be administrated to the population groups so that the fulfillment of the containment objectives is maximized. As a practical example for this analysis, vaccination against COVID-19 in Mexico was considered. However, this methodology can be applied to other countries’ data or to characterize future vaccines with time-dependent effectiveness values. Since this strategy uses aggregated observational data collected from massive databases, assumptions about the data validity and the course of the studied epidemic could eventually be necessary.

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In this work, a quantitative spectroscopic study of the bleaching phenomena occurring in plasticized formulations containing poly(vinyl chloride) was performed, proposing a general methodology to comparatively analyze the effect of degrading conditions on the polyene accumulation behaviors (PABs) exhibited by a set of tested formulations. In the study, a set of environmental indexes (temperature (T*), UV energy (UV*), and days with rain) were proposed, which allowed for the suitable globalization of the changing environmental conditions occurring throughout the different degrading periods. A procedure to numerically describe the PAB, followed by each formulation undergoing each degrading condition was also proposed, which required only two primary fitting parameters and four secondary fitting parameters. Then, the combined effects of certain environmental conditions on the PABs were studied, quantifying the stabilizing effects of the rain and the combined decrement on the T* and UV* indexes. Finally, on the basis of the proposed fitting equation and the values of its fitting parameters, the relative importance of the dehydrochlorination reactions as compared with the photo-oxidative reactions simultaneously occurring in the studied systems was estimated.

Summary: Two series of plasticized PVC formulations were prepared, containing one of the following di (2-ethyl hexyl phthalate)/epoxidized soybean oil ratios (phr/phr): (a) 35/3, (b) 55/3, (c) 45/0 or, (d) 45/6. For each ratio, the following calcium stearate/ zinc stearate ratios (phr/phr) were considered: (a) 0.6/0.4, (b) 0.8/0.2 or, (c) 1.0/0.0; all formulations were prepared with a total content of stearate(s) of 1.0 phr. The difference between the series was the preheating of stearates (150 8C, 90 min), carried out before the dry-blend preparation. The changes of tensile properties produced by the degradation process were measured in ribbons obtained by extrusion.

The obtainment of suitable values for metabolizable energy requires the previous knowledge of accurate and precise values of the heat of combustion of the different macronutrients. Thus, in this work, the heats of combustion of six carbohydrates (glucose, fructose, sucrose, maltose, starch, and cellulose) were experimentally measured, and such values were statistically compared with equivalent bibliographic values collected in a parallel work (Heats of combustion of the main carbohydrates in vegetable foods: a bibliographic approach, 2019), proposing, for each carbohydrate, an “overall interval” and an actualized representative value, which were estimated considering jointly the bibliographic and experimental information. Besides, a numerical methodology that used such parameters and the relative content of the different carbohydrates in selected foods was proposed, to estimate the global heat of combustion producible by the carbohydrate mass contained in such foods. The results estimated for 68 foods were globalized to propose the following generalized heats of combustion: (a) for fruits: 3.88 kcal/g, (b) for vegetables: 3.98 kcal/g and, and (c) for cereals: 4.13 kcal/g. These results demonstrated that the use of the Atwater's value (4.2 kcal/g of carbohydrate of vegetable source) involves a clear overestimation of the heat of combustion of the carbohydrate mass contained in vegetable source foods.