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La educación en cualquier campo es necesaria según las etapas de la vida por la cual estemos pasando, siendo fundamental conocer lo esencial para poder ir contestando todos aquellos interrogantes que van surgiendo con el transcurrir de los años; deseamos que exista una persona que los responda de la mejor manera, o simplemente que aquella escuela que todos tenemos: la familia, sea un medio de enseñanza en algunos tópicos para los cuales no hay libertad de expresión, como lo es el caso de la sexualidad.

This study assesses the production potential, environmental impact, and economic viability of generating biohydrogen from biomethane obtained from the organic fraction of municipal solid waste (MSW) using steam methane reforming with carbon capture and storage (CCS). As the emissions are biogenic, CCS results in negative emissions. The methodology is based on a previously developed model, including techno-economic analysis based on the levelised cost of hydrogen (LCOH) and mobility (LCOM), and environmental assessment, focusing on production potential, cost estimates, and emissions impact. A case study is conducted to assess the feasibility of using this biohydrogen with negative emissions to decarbonize Madrid's public bus fleet. The findings reveal that Madrid's MSW could meet the entire hydrogen fuel demand if the fleet consisted of fuel-cell buses. However, given the high costs of replacing the entire fleet, a net-zero solution is proposed, combining 60% fuel-cell buses with existing natural gas-powered buses. In this configuration, the negative emissions from biohydrogen offset the fossil emissions from natural gas and 40% of biomethane is saved. The cost of the net-zero fleet ranges between 192.55 and 209.37 €/100 km, comparable with 100% natural gas fleet, which ranges between 176.19 and 217.69 €/100 km., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

One of the ways to make cost-competitive electricity, from concentrated solar thermal energy, is increasing the thermoelectric conversion efficiency. To achieve this objective, the most promising scheme is a molten salt central receiver, coupled to a supercritical carbon dioxide cycle. A key element to be developed in this scheme is the molten salt-to-CO 2 heat exchanger. This paper presents a heat exchanger design that avoids the molten salt plugging and the mechanical stress due to the high pressure of the CO 2 , while improving the heat transfer of the supercritical phase, due to its compactness with a high heat transfer area. This design is based on a honeycomb-like configuration, in which a thermal unit consists of a circular channel for the molten salt surrounded by six smaller trapezoidal ducts for the CO 2 . Further, an optimization based on the exergy destruction minimization has been accomplished, obtained the best working conditions of this heat exchanger: a temperature approach of 50 °C between both streams and a CO 2 pressure drop of 2.7 bar.

Objectives: To confirm that high differential pressure (DP) supposes greater risk of ischaemic cardiopathy and to assess whether it is also an independent risk factor of suffering a cerebrovascular accident., Design: An analytical, observational, retrospective and longitudinal study with historic cohorts., Setting: Urban population of about 18 000 inhabitants., Participants: 300 patients aged between 15 and 75 with hypertension of > or =2 years evolution, who have had their blood pressure taken by nurses 4 or more times (excluding casualty) and have not suffered a cardiovascular event (CVE), whether coronary accident, cerebrovascular accident or peripheral vasculopathy., Main Measurements: The history relating to cardiovascular risk was recorded: lipaemia, obesity, tobacco dependency, diabetes mellitus, left ventricular hypertrophy (LVH). These factors were considered present if their diagnosis preceded the CVE diagnosis. They were placed in 2 groups, depending on the degree of differential pressure: "high" if >60 mm Hg and "not high" if (3/4)60 mm Hg. They were analysed for intention to treat over 10 years, with the appearance or not of a CVE as a response variable., Results: 300 participants (73.3% women), 150 exposed to risk and 150 not exposed. The initial analysis showed significant differences between the 2 groups for age (P<.0001), diabetes (P<.0001), and LVH (P<.001). After logistic regression, the OR of suffering LVH was 2.38 (95% CI, 1.19-4.74) in the group with high DP; the OR of ischaemic cardiopathy, 2.84 (95% CI, 1.16-6.96); and of cerebrovascular accident, 2.70 (95% CI, 1.09-6.68). There were no significant differences for peripheral arteriopathy., Conclusions: DP was confirmed as an independent factor of cardiovascular risk and, despite the limitations of the study, it was pointed to as a possible independent factor of cerebrovascular risk.