Modelos discretos de transmisión de COVID-19 y publicaciones preeliminares en la ciencia: una búsqueda sistematizada

In the Chinese city of Wuhan at the end of 2019, a new respiratory disease known as COVID-19 emerged, caused by the SARS-CoV-2 virus. This disease spreads rapidly worldwide and presents numerous infections and deaths; therefore, the World Health Organization upgraded its category from epidemic to pandemic because of alarming levels of spread, severity, and inaction. Given this situation, different areas of science have approached the study of this disease, among them is mathematical epidemiology through the modeling of the phenomenon; therefore, in this document, we performed a systematic review related to transmission models of COVID-19, specifically discrete models because of the daily report of infection cases around the world. We identified different important disease features implemented in the models, e.g., metapopulations, migration, quarantine, inclusion of latency, and incubation periods, among others. Also, we identified its basic structure, and we found that many papers directly used SIR and SEIR models with no modification, being an excessive simplification of the COVID-19 transmission phenomenon. Likewise, some authors highlighted an important problem during the application of mathematical models: the quality or absence of the daily case data in some affected countries. Finally, the mathematical models should be constantly updated together with the publication of research related to virology and epidemiology of the disease.A finales del año 2019, en la ciudad china de Wuhan, emergió una nueva enfermedad respiratoria conocida como COVID-19 que es producida por el virus SARS-CoV-2, similar al virus causante del síndrome respiratorio agudo grave (SARS-CoV). Actualmente, esta enfermedad se esparció rápidamente a nivel mundial y ha presentado una gran cantidad de afectados en diferentes regiones del mundo; por lo tanto, la Organización Mundial de la Salud elevó su categoría de epidemia a pandemia debido a los niveles alarmantes de propagación, gravedad e inacción. Dada esta situación, diferentes áreas de la ciencia han abordado su estudio, entre ellas esta la epidemiología matemática a través del modelado del fenómeno; por lo tanto en el presente documento se realizó una revisión sistematizada de literatura relacionada a modelos de transmisión del COVID-19, específicamente modelos discretos debido a la naturaleza de reporte diaria de casos de la enfermedad en diferentes localidades del mundo. Se lograron identificar diferentes características importantes de la enfermedad que son implementadas en los modelos matemáticos: división por grupos etarios, metapoblaciones, migración, cuarentena, inclusión de periodos de latencia e incubación, entre otros. Aun así, se encontró una gran cantidad de artículos que utilizaban directamente modelos SIR y SEIR sin ningún tipo de modificación, haciendo una simplificación desmedida del fenómeno de transmisión del COVID-19. Asimismo, se identificaron algunas problemáticas a la hora de implementar los modelos matemáticos: la presencia y calidad de los datos de casos diarios en algunos países afectados. Finalmente, se sugiere que los modelos matemáticos estén en constante actualización junto a la publicación de las investigaciones relacionadas con virología y epidemiología de la enfermedad

Propuesta de gestión de existencias de combustibles líquidos en el Perú

El Perú tiene una política de seguridad energética relacionada a las existencias de combustibles líquidos que obliga a los Productores y Distribuidores Mayoristas a mantener existencias mínimas y promedio de combustibles líquidos equivalentes a 5 y 15 días de sus ventas, respectivamente. Sin embargo, existe una falta de infraestructura de almacenamiento que permita cubrir el abastecimiento en caso de emergencias. Luego se analizar el mercado de combustibles líquidos, se concluyó que el Perú necesita 20 días de existencias mínimas para atenuar los riesgos identificados, cuya cobertura debería ser asumida tanto por los agentes obligados como por el Estado. Así, se plantea incrementar la obligación de los agentes privados de 5 a 8 días mínimo de existencias y eliminar la obligación de 15 días promedio. Los 12 días mínimos restantes, serían asegurados por el Estado, mediante una Asociación Público Privada (APP), en el cual se encargue a un privado la construcción, operación y mantenimiento de tanques de almacenamiento, así como la gestión de las existencias requeridas para garantizar la seguridad energética nacional. Este proyecto sería autosostenible y los costos estarían asegurados por la demanda

Immunization with surface immunogenic protein induces a decrease of vaginal colonization by group B Streptococcus in an experimental mouse model

The Group B streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis in developed countries and an emerging pathogen in adults. A neonatal infection occurs predominantly during the delivery by either inhalation or ingestion of contaminated secretions of the mother’s vagina. Maternal screening by rectovaginal GBS colonization at 35–37 weeks of gestation, with subsequent intra-partum antibiotic prophylaxis (IAP) at the onset of labor, is implemented in some countries to prevent newborn invasive by GBS. Currently, there are not vaccines to prevent the devastating consequences of GBS and a glycoconjugate vaccine is under clinical experimentation (Clinical Trials Phase III). The Surface Immunological Protein (SIP) of GBS is highly immunogenic and conserved between different serotypes of this bacterium. The SIP had been described to induce antibodies type IgG that induces protective immunity in animal model challenged intraperitoneally with GBS. Here we describe the immunization with SIP mixed with an AbISCO-100 adjuvant in mice model challenged to GBS vaginal infection. The vaccine has demonstrated to decrease the GBS colonization in infected mouse. The SIP immunization has also increased the circulating IgA, IgG and IgG2a levels against SIP and antigen-specific circulating levels of IFN- ƴ and IL–2. Moreover, transfer of serum and T cells from a vaccinated animal into a non-immunized animal induced immune protection to the animals from challenged GBS colonization of the vaginal tract. In conclusion, we have demonstrated that a simple and effective vaccine is able to prevent GBS colonization, where cellular immunity plays an important role. To our knowledge, is the first report the SIP-based vaccine reduces the vaginal GBS colonization in an animal model

Understanding the impact of hamstring injuries on match performance in Spanish professional soccer players: two full seasons follow-up

This study aimed to analyze the changes in match physical demands in professional soccer players after sustaining a hamstring injury, which was categorized based on injury severity. Seventy-two hamstring injuries involving sixty-four professional soccer players from the Spanish LaLiga™ were considered for this study. All injuries were classified according to their severity as moderate (resulting in eight to 28 missed days) and major (resulting in more than 28 missed days). Mediacoach video-tracking system collected time and external load variables and subsequently compared them between the pre-injury and return-to-play periods. The analyzed variables included distance covered at different velocities (i.e., total distance, at 18-21 km.h−1, at 21-24 km.h−1, and at more than 24 km.h-1), the number of sprints, accelerations, decelerations, and high metabolic load distance (HMLD). The results showed that players with both moderate and major injuries played fewer minutes after injury (p<.001 to p<.05) and experienced a decrease in maximum speed (p<.01 to p<.05), covering less total distance (p<.05) and exhibiting a decrease (p<.05) in average speed (only observed in players with major injuries). Additionally, moderately injured players experienced a reduction in the number of maximum accelerations (p<.05) and decelerations (p<.05), high metabolic load distance/min (p<.05), and average accelerations (p<.05). Furthermore, a significant reduction in the magnitude of maximum decelerations was observed in players with major injuries (p<.05). These findings highlight the importance of implementing strategies that enable the attainment of initial levels of high-intensity actions and maximum speed in reconditioning programs following hamstring injuries

El síndrome de norte-sur, una complicación de la asistencia circulatoria con ECMO Venoarterial. Reporte de caso

We present the case of a 34-year-old male patient with a history of Marfan syndrome who was admitted to the emergency room for acute aortic regurgitation secondary to aneurysmal dilation of the ascending thoracic aorta. In the postoperative period, post-cardiotomy cardiogenic shock was documented, so circulatory support was initiated with peripheral Veno-Arterial ECMO, which developed hypoxemia due to bacterial pneumonia and data compatible with North-South syndrome. We present a review, non-conventional cannulation strategies and a diagnostic alternative for this entity.Presentamos el caso de un paciente masculino de 34 años con diagnóstico previo de síndrome de Marfan que ingresó por Insuficiencia aórtica aguda secundario a dilatación aneurismática de la aorta torácica ascendente. En el posoperatorio se documentó choque cardiogénico poscardiotomía por lo que se inició soporte circulatorio con ECMO venoarterial periférico, el cual desarrolló hipoxemia por neumonía bacteriana y datos compatibles con síndrome norte-sur. Presentamos una revisión, estrategias de canulación no convencional y una alternativa diagnóstica para esta entidad

Generation of bioelectricity from organic fruit waste

This research proposes an alternative for companies and farmers through the production of electricity using microbial fuel cells (MFCs) using waste from export products. Nine MFCs were manufactured with zinc and copper electrodes; and as substrates, pineapple, potato and tomato pulp wastes were used in the anode chamber, and residual sludge in the cathode chamber. It was observed that the MFCs with pineapple substrate generated higher values of the electrical parameters, resulting in voltage and current values of 0.3484 ± 0.003 V and 27.88 ± 0.23 mA, respectively. It was also observed that the maximum power density was 0.967 ± 0.059 W/cm2 at a current density of 0.04777 A/cm2 for the same substrate. Acid pH values were observed in the three samples, while the conductivity reached its maximum value on day 23 (69.47 ± 0.91 mS/cm) which declined until the last day of monitoring; the turbidity values increased abruptly after day 22 until the last day where a value of 200.3 ± 2.52 UNT was observed for the pineapple substrate. The scanning electron microscopy for the pineapple substrate MFC electrodes shows the formation of a porous biofilm on the zinc and copper electrodes. These results show that a new form of electricity production has been achieved by generating high voltage and current values, using low-cost materials

Actitudes hacia la busqueda de empleo y su relacion con estrategias de afrontamiento y autoeficacia, en personas con diagnostico de esquizofrenia en su fase de recuperacion e integracion social

109 p.Controlando el deterioro cognitivo, se evaluaron las actitudes hacia la búsqueda de empleo y su relación con las estrategias de afrontamiento, y la autoeficacia percibida en personas con diagnóstico de esquizofrenia, que se encuentran en las fases de recuperación e integración social y que asisten a centros de rehabilitación del Servicio de Salud del Maule. De acuerdo a los resultados obtenidos, se encontró que las personas con diagnóstico de esquizofrenia que poseen estrategias de afrontamiento centradas en el problema y mayores niveles de autoeficacia no presentan actitudes positivas frente a la búsqueda de empleo, lo cual puede estar asociado a múltiples factores que son discutido

Green Energy Generated in Single-Chamber Microbial Fuel Cells Using Tomato Waste

"This research used tomato waste as a substrate (fuel) in Single Chamber-Microbial Fuel Cells (scMFC) on a small scale. The electrochemical properties were monitored, the functional groups of the substrate were analyzed by Fourier Transform Infrared Spectrophotometry (FTIR) and a microbiological analysis was performed on the electrodes in order to identify the microorganisms responsible for the electrochemical process. The results show voltage peaks and an electrical current of 3.647 ± 0.157 mA and 0.957 ± 0.246 V. A pH of 5.32 ± 0.26 was measured in the substrate with an electrical current conductivity of 148,701 ± 5849 mS/cm and an internal resistance (Rint) of 77. 517 ± 8.541 Ω. The maximum power density (PD) displayed was 264.72 ± 3.54 mW/cm2 at a current density (CD) of 4.388 A/cm2 . On the other hand, the FTIR spectrum showed a more intense decrease in its peaks, with the compound belonging to the phenolic groups being the most affected at 3361 cm−1 . The micrographs show the formation of a porous biofilm where molecular identification allowed the identification of two bacteria (Proteus vulgaris and Proteus vulgaris) and a yeast (Yarrowia lipolytica) with 100% identity. The data found show the potential of this waste as a source of fuel for the generation of an electric current in a sustainable and environmentally friendly way, generating in the near future a mechanism for the reuse of waste in a beneficial way for farmers, communities and agro-industrial companies.