RESUMEN El desarrollo de nanocatalizadores de alto rendimiento depende de la generación de sitios superficiales estables y activos a escala atómica mediante el control sistemático del tamaño, la forma y la composición química de metales y óxidos metálicos a nanoescala. En este trabajo se mencionan la síntesis y aplicación de nanomateriales basados principalmente en alúmina (Al2O3), Titania (TiO2) y algunos otros de menor uso como el óxido de cerio (CeO2). Asimismo, se describen brevemente sus características morfológicas, texturales y fases cristalográficas obtenidas. Se destaca la importancia de los métodos de síntesis en la morfología y estructura de las nanopartículas y cómo esto afecta a la actividad catalítica de los soportes y catalizadores preparados con ellas.

ABSTRACT The development of high-performance nanocatalysts depends on generating stable and active surface sites at the atomic scale by systematically controlling the size, shape, and chemical composition of metals and metal oxides at the nanoscale. In this work, the synthesis and application of nanomaterials based mainly on alumina (Al2O3), Titania (TiO2), and some others of minor use, such as cerium oxide (CeO2), are mentioned. Furthermore, their morphological and textural characteristics and crystallographic phases obtained are briefly described. The importance of the synthesis methods in the morphology and structure of the nanoparticles and how this affects the catalytic activity of the supports and catalysts prepared with them is highlighted.

ABSTRACT Cognitive functioning is acquiring special relevance when studying the factors that influence soccer performance. Although the relationship between cognitive functions and sport performance has an extensive literature in adult soccer players, the same does not happen in young players, where this association has not been explored in depth. This work arises with the objective of knowing the state of the issue and going in depth in this line of research in youth categories, between 8 and 19 years old. For this purpose, a systematic review has been carried out on the existing relationship between cognitive functioning and sports performance in youth soccer players. In order to carry out this systematic review, the articles published on this issue in the last 10 years were analyzed following the PRISMA method. For an exhaustive search of the literature, the database Web of Science (WoS), SCOPUS, Dialnet, PubMed and Google Scholar, among others, were used, including articles published both Spanish and English. Finally, 12 articles were analyzed and included in the review. The results showed significant relationship between cognitive functions and performance in youth soccer players, highlighting variables such as attention, inhibitory control, cognitive flexibility or decision making, finding differences between scores obtained by elite soccer players and those obtained by amateur athletes or general population, being significantly higher in the first group.

RESUMEN El funcionamiento cognitivo está adquiriendo especial relevancia a la hora de estudiar los factores que influyen en el rendimiento en fútbol. Si bien la relación entre funciones cognitivas y rendimiento deportivo cuenta con una literatura extensa en futbolistas adultos, no ocurre lo mismo en jugadores de edades tempranas, donde dicha asociación no se ha explorado en profundidad. Este trabajo surge con el propósito de conocer el estado de la cuestión y profundizar en esta línea de investigación en categorías infantiles y juveniles, de edades comprendidas entre los 8 y 19 años. Para ello, se ha llevado a cabo una revisión sistemática sobre las relaciones existentes entre el funcionamiento cognitivo y el rendimiento deportivo en jóvenes futbolistas. Para la realización de dicha revisión sistemática se analizaron los artículos publicados sobre esta cuestión en los últimos 10 años siguiendo el método PRISMA. Para una búsqueda exhaustiva de la literatura existente se han utilizado las bases de datos Web of Science (WoS), SCOPUS, Dialnet, PubMed y Google Scholar, entre otras, incluyendo artículos publicados tanto en lengua castellana como inglesa. Finalmente, 12 artículos fueron analizados e incluidos en la revisión. Los resultados mostraron que existen relaciones significativas entre las funciones cognitivas y el rendimiento en jóvenes futbolistas, de entre las cuales destacan variables como la atención, el control inhibitorio, la flexibilidad cognitiva o la toma de decisiones, encontrándose diferencias entre las puntuaciones obtenidas por futbolistas de élite y las obtenidas por deportistas amateurs o población general, siendo significativamente mayores en el primer grupo.

RESUMO O funcionamento cognitivo está adquirindo especial relevância no estudo dos fatores que influenciam o desempenho no futebol. Embora a relação entre funções cognitivas e desempenho esportivo seja extensa na literatura em jogadores de futebol adulto, o mesmo não ocorre em jogadores de tenra idade, onde essa associação ainda não foi explorada em profundidade. Este trabalho surge com o objetivo de conhecer o estado da questão e aprofundar esta linha de pesquisa nas categorias infanto-juvenil, na faixa etária entre 8 e 19 anos. Para tanto, foi realizada uma revisão sistemática sobre as relações entre funcionamento cognitivo e desempenho esportivo em jovens jogadores de futebol. Para a realização desta revisão sistemática, os artigos publicados sobre o assunto nos últimos 10 anos foram analisados segundo o método PRISMA. Para uma busca exaustiva da literatura existente, foram utilizadas as bases de dados Web of Science (WoS), SCOPUS, Dialnet, PubMed e Google Scholar, entre outras, incluindo artigos publicados em espanhol e inglês. Por fim, 12 artigos foram analisados e incluídos na revisão. Os resultados mostraram que existem relações significativas entre funções cognitivas e desempenho em jovens jogadores de futebol, entre as quais se destacam variáveis como atenção, controle inibitório, flexibilidade cognitiva ou tomada de decisão, encontrando diferenças entre os escores obtidos por jogadores de futebol de elite e aqueles. obtidos por atletas amadores ou pela população em geral, sendo significativamente maior no primeiro grupo.

Introduction: The clinical presentation of COVID-19 pneumonia has been well documented; however, its long-term repercussions are still a matter of investigation. Objective: to evaluate the occupational, clinical and functional respiratory recovery, 3 months after the discharge of patients hospitalized for SARS-CoV-2 pneumonia, in relation to the ventilatory therapy received. Patients and Methods: A prospective cohort of 116 patients with COVID-19 pneumonia from Hospital Naval Almirante Nef (Viña del Mar, Chile) was analyzed, with clinical and functional respiratory follow-up at 3 months after being discharged. Results: Median follow-up: 100 days. Composition of the cohort: 75 men, median age 60 years-old, 50% obese, 34.5% smokers and 13.8% with respiratory comorbidity. 16% received rehabilitation. Dyspnea was reported in 48.3% and fatigue in 33.6%. Only 54.8% returned to work. 65.2% who used oxygen therapy (O2) returned to work compared to 44% who used high-flow nasal cannula (HFNC) and 33.3% with invasive mechanical ventilation (IMV). Mostly the O2 group returned to normal life compared to HFNC and VMI (71.4 versus 17.5% and 11.1% respectively). Lung function was normal in 39 patients (33.6%). The series that returned to normal life had higher percentage of normal DLCO and six-minute walk test. Compared to the O2 series, the CNAF series had a higher frequency of DLCO alteration (OR = 5) followed by the VMI series (OR = 3.6). Conclusion: At 3 months of follow-up, absenteeism from work, persistence of symptoms and respiratory functional alteration (DLCO) were evident, especially in those who received ventilatory support in addition to oxygen therapy.

Resumen Introducción: La presentación clínica de neumonía por COVID-19 ha sido bien documentada; sin embargo, sus repercusiones a largo plazo son aún motivo de investigación. Objetivo: Evaluar la recuperación laboral, clínica y funcional respiratoria, a 3 meses del egreso de pacientes hospitalizados por neumonía por SARS-CoV-2, en relación con la terapia ventilatoria recibida. Pacientes y Métodos: Se analizó una cohorte prospectiva de 116 pacientes con neumonía por COVID-19 del Hospital Naval Almirante Nef de Viña del Mar, con seguimiento clínico y funcional respiratorio 3 meses después de su alta. Resultados: Mediana del seguimiento: 100 días. Constitución de la cohorte: 75 hombres, mediana de edad 60 años, 50% obesos, 34,5% fumadores y 13,8% con comorbilidad respiratoria. 16% recibió rehabilitación. Se reportó disnea en 48,3% y fatigabilidad en 33,6%. Solo 54,8% retornó al trabajo. El 65,2% que utilizó oxigenoterapia (O2) volvió a trabajar comparado con 44% que utilizó cánula nasal de alto flujo (CNAF) y 33,3% con ventilación mecánica invasiva (VMI). Mayoritariamente el grupo de O2 volvió a la vida normal en comparación con CNAF y VMI (71,4 versus 17,5% y 11,1% respectivamente). La función pulmonar fue normal en 39 pacientes (33,6%). La serie que volvió a vida normal tuvo mayor porcentaje de DLCO y test de caminata de 6 minutos normales. En comparación con la serie O2, la serie CNAF tuvo mayor frecuencia de alteración de DLCO (OR = 5) seguido por la serie VMI (OR = 3,6). Conclusión: A 3 meses de seguimiento, se evidenció ausentismo laboral, persistencia de síntomas y alteración funcional respiratoria (DLCO), especialmente en quienes recibieron soporte ventilatorio adicional a oxigenoterapia.

Abstract In this work the self-assembling of InAs quantum dots (QDs) within asymmetric barriers of (Al)GaAs is studied via reflection high energy electron diffraction (RHEED). A comparative study between the AlGaAs/InAs/GaAs interfaces and its mirror-like heterostructure GaAs/InAs/AlGaAs showed significant differences in the self-assembling and capping of the QDs. The critical thickness of InAs QDs was proven to be larger when it is grown on AlGaAs alloys, compared with the deposition on GaAs layers. This change is explained by the reduced mobility of In atoms on the Al-containing surfaces, for which the QDs density is increased. Through the in-situ analysis of diffusion parameters, it is concluded that the mobility of In atoms decreases the mass transport of 2D and 3D precursors that conduces to the self-assembling of the QDs nanoislands, modifying the rate at which the QDs are formed. Further, during the first stages of QDs capping it is observed that the III-V materials intermixing plays a predominant role. The nanoislands are less affected when are covered by AlGaAs in comparison with the GaAs capping, preserving the QDs morphology and avoiding materials alloying. By following the RHEED intensity behavior during the QDs capping, a model was proposed to obtain quantitative parameters for the smoothing process. High-resolution x-ray diffraction (HRXRD) measurements show the composition of sharp interfaces for the AlGaAs/InAs/GaAs heterostructure. Lastly, numerical simulations were performed to evaluate the strain changes using the experimental information as input data.

Abstract: Central obesity is known as an indicator of cardiometabolic risk, but better anthropometric measures than Body Mass Index (BMI) are needed to detect it. Waist-to-height ratio (WHtR) is an indicator of central adiposity and a strong predictor of cardiometabolic risk. Objective: To determine the pre valence of cardiometabolic risk in a representative sample of Costa Rican children and adolescents. Patients and Method: Cross-sectional and descriptive study carried out with 2,684 students from 64 educational centers in Costa Rica. Validated questionnaires were applied to the students and their weight, height, and waist circumference were determined. Weight and body fat percentage of the students were determined with a Tanita model SC-331 S (without column). Height was measured with a SECA stadiometer model 217. The abdominal circumference was estimated using a tape measure. BMI and WHtR were calculated for each participant. The behavior of the indicator WHtR was analyzed with logistic regression models. All procedures were approved by the Ethics Committee of INCIENSA. Results: There was a strong and positive correlation between waist circumference and BMI (r = 0.748, p < 0.001, 56% of shared variance), and a positive and moderate correlation between WHtR and BMI (r = 0.611, p < 0.01, 37% of shared variance). Conclusions: A third part of the stu dent population of elementary, middle, and high schools (31.8%) is at cardiovascular and metabolic risk.

Resumen: La obesidad central es un indicador de riesgo cardiometabólico, pero se necesitan mejores medidas antropométricas que el Índice de Masa Corporal (IMC) para detectarlo. La relación cintura-estatura (WHtR) es un indicador de adiposidad central y fuerte predictor de riesgo cardiometabólico. Obje tivo: Determinar la prevalencia de riesgo cardiometabólico en una muestra representativa de niños y adolescentes costarricenses. Pacientes y Método: Estudio transversal y descriptivo realizado con 2 684 estudiantes de 64 centros educativos de Costa Rica. Se aplicaron cuestionarios validados a los estudiantes y se les determinaron el peso, la talla y la circunferencia de cintura. El peso (kg) y la grasa corporal se midieron mediante análisis de bioimpedancia en una báscula Tanita SC-331 S (sin colum na). La estatura se midió con un estadiómetro marca SECA, modelo 217. Para estimar la circunferencia de cintura, se usó una cinta métrica. Se calcularon el IMC y la relación WHtR de cada participante. Para analizar el comportamiento de la relación WHtR se ejecutaron modelos de regresión logística. Todos los procedimientos fueron aprobados por el Comité Ético del INCIENSA. Resultados: Se en contró una correlación fuerte y positiva entre circunferencia abdominal e IMC (r = 0,748, p < 0,001, 56% de varianza compartida), y una correlación positiva y moderada entre WHtR e IMC (r = 0,611, p < 0,01, 37% de varianza compartida). Conclusiones: La tercera parte de la población estudiantil de escuelas y colegios (31,8%) de Costa Rica se encuentra en riesgo cardiometabólico.

ABSTRACT In the present work, in order to estimate the semi-amplitude of the radial velocity, we evaluate the contribution of the Doppler beaming effect to the phase curves of the all confirmed extrasolar planets (2776, September 2019), observed so far by the Kepler telescope. By modeling the tiny photometric variations (reflection, ellipsoidal and Doppler beaming effects) of the light curves, we found that the best observational data are in close agreement with the theoretical and published values of the amplitudes only for exoplanets: KOI-13b and TrES-2b. The derived values for the radial velocity also are in good agreement with those published by some authors. Furthermore, we found it necessary to introduce a third harmonic (3φ) contribution into the KOI-13b and HAT-P7b light curve models, in order to decrease the residuals.

RESUMEN En el presente trabajo, con el fin de estimar la semi-amplitud de la velocidad radial, evaluamos la contribución del efecto Doppler beaming a las curvas de fase de todos los planetas extrasolares confirmados (2776, septiembre de 2019), observados hasta ahora por el telescopio Kepler. Modelando las pequeñas variaciones fotométricas (reflexión, efectos elipsoidales y de enfoque Doppler) de las curvas de luz, encontramos que los mejores datos observacionales están en acuerdo con los valores teóricos y publicados de las amplitudes solo para los exoplanetas: KOI-13b y TrES-2b. Los valores derivados para la velocidad radial también concuerdan con los publicados por algunos autores. Además, encontramos que es necesario introducir una tercera contribución armónica (3φ) en los modelos de curva de luz para KOI-13b y HAT-P7b, con el fin de reducir los residuos.

The research focused on the hydrothermal synthesis of a material based on a Kesterite structure of Cu2ZnSnS4 (CZTS). For this purpose, the component cations, in concentrations of 1.0 molL-1, were placed in a steel autoclave under different temperatures conditions (200, 220, 240, 260 and 280°C) for 32 h. After, the solids were calcined at 400°C for 2 h. UV-VIS results showed that materials had a strong tendency to absorb in the region of 600-800 nm, with band-gap around 1.54 eV. XRD and Raman confirmed a structure with tetragonal geometry, preferably oriented along the (112) facet, as well as low frequency vibrational and rotational modes typical of CZTS. TEM showed nanometric crystallites (≈41.6 ����). XPS showed the Cu2+, Sn4+, Zn2+ and S4- species in correspondence with its main oxidation states. The electrical analysis, allowed to evaluate the behavior under load conditions, suggesting a potential use these materials for photovoltaic applications.

Resumen: Introducción: Los accidentes en motocicleta son una de las causas principales de muerte e incapacidad en la población joven de México. No hay estudios locales que describan el patrón de lesiones con base en la clasificación AO. Objetivo: Definir el patrón y tipo de fracturas óseas más frecuentes atendidas en un Hospital Regional de Alta Especialidad, de Enero a Agosto de 2017. Material y métodos: Estudio descriptivo, transversal, observacional, cuantitativo de 98 pacientes que sufrieron accidente en motocicleta y que ameritaron tratamiento ortopédico quirúrgico (94% hombres, 6% mujeres, media de edad 29.7 años). Resultados: Los accidentes más frecuentes incluyeron las siguientes características: conductores hombres, motocicleta < 150 cm3, área rural, sin uso de casco (75.5%) y colisión contra un objeto en movimiento. Las fracturas más frecuentes correspondieron a: tibia y peroné (28.9%), fracturas expuestas (52.3%), de fémur (25%) y antebrazo (10.5%). Considerando la clasificación AO las fracturas más frecuentes fueron AO 42 B 3.3, AO 32A3.2 y AO 23B1.2. Conclusión: Los motociclistas utilizan escasas medidas de protección. El patrón de lesiones evidenció diferencias con lo reportado a nivel nacional. De acuerdo con la clasificación AO, buena parte de los casos corresponden a los de peor pronóstico.

Abstract: Introduction: Motorcycle accidents are one of the leading causes of death and disability in Mexico’s young population. There are no local studies describing the pattern of AO-based injuries. Objective: Define the pattern and type of most common bone fractures in a Regional Hospital of High Specialty, from January to August 2017. Material and methods: Descriptive, cross-sectional, observational, quantitative study of 98 patients who suffered motorcycle accidents and who merited surgical orthopedic treatment (94% men, 6% women, average age 29.7 years). Results: The most frequent accidents included the following features: male drivers, motorcycle < 150 cm3, rural area, without helmet use (75.5%) collision against a moving object. The most common fractures corresponded to: tibia and fibula (28.9%), open fractures (52.3%), femur (25%) forearm (10.5%). Considering the AO classification the most common fractures were AO 42 B 3.3, AO 32A3.2 and AO 23B1.2. Conclusion: Motorcyclists use few protective measures. The injury pattern showed differences with what was reported nationally. According to the AO rating, much of the cases correspond to those of worst prognosis.

Abstract The constant advances in the field of lung cancer immunotherapy have recently reached the treatment of locally advanced disease with the approval of durvalumab after concurrent chemoradiation. However, radiation therapy continues to be key for controlling the disease at this stage. Over the years, different strategies have been employed to try to optimize outcomes using radiotherapy, with cardiac and pulmonary toxicity as the main limitation on its success. The interest in the use of hypofractionation and stereotactic body radiation therapy for stage III non-small cell lung cancer has increased as knowledge regarding these kinds of treatments has been enhanced. Hypofractionation is a relatively frequent treatment, although the level of evidence that supports it is limited. For its part, stereotactic body radiation therapy has been particularly studied as a boost after chemoradiation, with encouraging results. In both cases, study of how to integrate these tools with chemotherapy and particularly with immunotherapy is essential, as they may have an immunomodulatory role.

Resumen Los constantes avances en el campo de la inmunoterapia en cáncer de pulmón se han visto reflejados en la aprobación de durvalumab para el tratamiento de la enfermedad localmente avanzada tras radioterapia y quimioterapia concurrente. Sin embargo, la radioterapia sigue siendo clave para el control de la enfermedad en este estadio. A lo largo de los años se han utilizado varias estrategias para tratar de optimizar su papel, siendo la toxicidad cardíaca y la pulmonar las principales barreras. En este contexto, el interés por el uso del hipofraccionamiento y la radioterapia estereotáxica fraccionada para el cáncer de pulmón no microcítico estadio III ha ido en aumento. El hipofraccionamiento es un tratamiento relativamente extendido aunque el nivel de evidencia que lo acompaña sea limitado. Por su parte, la radioterapia estereotáxica fraccionada se ha estudiado especialmente como una técnica para sobredosificar áreas concretas de la enfermedad tras el tratamiento con radioquimioterapia. En ambos casos, el estudio de cómo integrar estas herramientas radioterápicas con la quimioterapia, y especialmente con la inmunoterapia, es esencial, dado que pueden jugar además un papel inmunomodulador.

Abstract Background Heart failure (HF) is the leading cause of hospitalization for aging populations in Western countries, and is showing an increasing mortality. The aim of this study was to assess the probable long-term mortality risk factors for patients admitted because of HF. Methods Retrospective study of a cohort of 202 patients consecutively hospitalized because of HF and followed up for a maximum period of 5 years. Clinical and epidemiological factors and their relationship to in-hospital and long-term mortality were analyzed. Results In-hospital mortality was 16%.The independent predictors were: age >75 years (HR = 2.68, 95% IC: 1.65-4.36, p = 0.001); cognitive impairment (HR = 2.77, 95% IC: 1.40-5.48, p = 0.004); Barthel index ≥60 (HR = 0.54, 95% IC: 0.37-0.78, p = 0,009); creatinine levels >1.16 mg/dl at admission (HR = 1.57, 95% IC: 1.12-2.20, p = 0.009); and number of diagnostics >10 on discharge (HR = 1. 64, 95% IC: 1.14-2.36, p = 0.007). Accumulated mortality at 12, 24, 36 and 48 months after hospital discharge were 43%, 51%, 67% and 70%, respectively; the independent predictors for this were: age >75 years (HR = 2.55, 95% IC: 1.56-4.15, p <0.001); cognitive impairment (HR = 2.45, 95% IC: 1.22-4.90, p = 0.011); creatinine levels >1.16 mg/dl on admission (HR = 1.59, 95% IC: 1.12-2.24, p = 0.009); systolic blood pressure >140 mm Hg on admission (HR = 0.56, 95% IC: 0.40-0.80, p <0.001); and number of diagnostics >10 on discharge (HR = 1. 49, 95% IC: 1.03-2.16, p = 0.033). Conclusions Clinical and epidemiological factors related to in-hospital and long-term mortality could help to improve the management of patients with HF.

Resumen Fundamento La insuficiencia cardíaca (IC) es la primera causa de hospitalización en países occidentales, con una mortalidad creciente. El objetivo fue describir los posibles factores pronósticos de mortalidad en pacientes hospitalizados por IC. Material y métodos Estudio retrospectivo de una cohorte de 202 pacientes consecutivos hospitalizados por IC, y seguidos durante un período máximo de 5 años. Se analizaron variables basales epidemiológicas y clínicas y su relación con la mortalidad hospitalaria y a largo plazo. Resultados La mortalidad durante el episodio índice de hospitalización fue del 16%. Las variables predictoras independientes de la mortalidad hospitalaria fueron: edad >75 años (HR = 2,68; IC 95%: 1,65-4,36; p = 0,001), presencia de deterioro cognitivo (HR = 2,77; IC 95%: 1,40-5,48; p = 0,004), índice de Barthel >60 (HR = 0,54; IC 95%: 0,37-0,78; p = 0,009), creatinina >1,16 mg/dL al ingreso (HR = 1,57; IC 95%: 1,12-2,20; p = 0,009) y >10 diagnósticos al alta (HR = 1,64; IC 95%: 1,14-2,36; p = 0,007). La mortalidad global acumulada a los 12, 24, 36 y 48 meses fue del 43%, 51%, 67% y 70%, respectivamente, y sus predictores independientes fueron: edad >75 años (HR = 2,55; IC 95%: 1,56-4,15; p <0,001), deterioro cognitivo al ingreso (HR = 2,45; IC 95%: 1,22-4,90; p = 0,011), creatinina >1,16 mg/dL al ingreso (HR = 1,59; IC 95%: 1,12-2,24; p = 0,009), presión arterial sistólica <140 mm Hg al ingreso (HR = 0,56; IC 95%: 0,40-0,80; p <0,001) y >10 diagnósticos al alta (HR = 1,49; IC 95%: 1,03-2,16; p = 0,033). Conclusiones Existen variables relacionadas con la mortalidad hospitalaria y a largo plazo que podrían ayudar a un mejor manejo de estos pacientes.

Abstract: Weeds are capable of producing significant changes in the structure, composition and processes of the agroecosystem, being able to affect the yield of the sugarcane crop by 20-25% or up to 97.5% if the competition for nutrients, water and light is permanent. The tasks carried out for its elimination, manual, mechanical and chemical control, increase production costs. In this sense, the incorporation of green manures is beneficial in favoring weed control, increasing the organic matter of the soil, improving its physical, chemical and biological properties, increasing the availability of nutrients and reducing the use of mineral fertilizers. The aim of the present study was to evaluate the behavior of the community of weeds in sugar cane, seed phase, using Sesbania herbacea as green manure. A randomized complete block design was carried out with three treatments: 1) S. herbacea (AV) green manure alone; 2) NPK nitrogen fertilization (160 60 80) and 3) PK fertilization (00 60 80) + AV, and four repetitions, where weeds were sampled on five dates, with the registered data diversity indices were calculated: richness (S ), diversity (H'), uniformity (E) and value of importance (IVI) of weeds. The highest S values were observed in the month of November in the three treatments, but they were always higher in treatment 2 (NPK); AV and PK+AV showed the lowest values in October and December. H’ varied from low to medium, in all treatments the highest values were observed in the last sampling. E varied from medium to high, highlighting its inverse relationship with S. The values of the diversity indices did not show statistical differences between treatments in the period studied, so it is recommended to do a long-term follow-up. The most important species in the community were C. rotundus, J. tamnifolia, P. niruri and I. triloba.

Resumen: Las arvenses son capaces de producir cambios significativos en la estructura, composición y procesos del agroecosistema, pudiendo afectar el rendimiento del cultivo de caña de azúcar en 20-25% o hasta 97.5% si la competencia por nutrientes, agua y luz es permanente. Las labores que se realizan para su eliminación, control manual, mecánico y químico, incrementan los costos de producción. En este sentido, la incorporación de abonos verdes resulta benéfica al favorecer el control de arvenses, aumentar la materia orgánica del suelo, mejorar sus propiedades físicas, químicas y biológicas, aumentar la disponibilidad de nutrientes y reducir el uso de fertilizantes minerales. El objetivo del presente estudio fue evaluar el comportamiento de la comunidad de arvenses en caña de azúcar, fase semilla, utilizando Sesbania herbacea como abono verde. Se realizó un diseño de bloques completos al azar con tres tratamientos: 1) abono verde de S. herbacea (AV) solo; 2) fertilización nitrogenada NPK (160 60 80) y 3) fertilización PK (00 60 80) + AV, y cuatro repeticiones, donde se realizaron muestreos de arvenses en cinco fechas, con los datos registrados se calcularon índices de diversidad: riqueza (S), diversidad (H’), Uniformidad (E) y de valor de importancia (IVI) de las arvenses. Los valores más altos de S se observaron en el mes de noviembre en los tres tratamientos, pero siempre fueron mayores en el tratamiento 2 (NPK); AV y PK+AV mostraron los valores más bajos en octubre y diciembre. H’ varió de baja a media, en todos los tratamientos los valores más altos se observaron en el último muestreo. E varió de media a alta, resaltando su relación inversa con S. Los valores de los índices de diversidad no mostraron diferencias estadísticas entre tratamientos en el periodo estudiado, por lo que se recomienda hacer un seguimiento a largo plazo. Las especies de mayor importancia en la comunidad fueron C. rotundus, J. tamnifolia, P. niruri e I. triloba.

Abstract: The current research paper presents the dynamic model from a UAV (Unmmaned Aerial Vehicle) type quad copter. The mentioned model simulates closest behavior, respect to a real performance when realizes basic movements. In order to develop the math, model the quadcopter has been considered as a rigid object with 6 DOF (six degrees of freedom), which is divided into translational and rotational coordinates, using a technique based on Euler-Lagrange Equations to model. In that way is possible to acquire the expressed transfer function on the quadcopter dynamic model. The UAV’s rotational dynamic is defined by the most important inertia moments, located in the vehicle center of mass. The inertia moments had been estimated using ‘Solidworks’ software. To achieve it the quadcopter was assembled with a minimum quantity of parts, after that, the design was uploaded into Simulink software to add complete the results including a 3d animation. A Control Strategy was attached to the quadcopter design, to stabilize the described plants, finally the performance is corroborated applying him external perturbations like gusts of wind, variable masses, looking to create instability during the flight, expecting for a system controlled reaction. The results showed the UAV stabilize to his reference position in less than twelve seconds (12) against a gust of wind that caused its horizontal displacement. This is an important application of the rotational dynamics of the UAV, using Simulink and the Simscape Multibody library in conjunction with Solidworks. Achieving a tool of great interest and therefore a significant contribution to the study of UAVs, giving the possibility of using of a practical tool for the design of quadrotors focused on different applications, such as precision agriculture.

Resumen: El propósito de este trabajo fue el de realizar el modelo dinámico de un vehículo aéreo no tripulado (VANT) tipo quadrotor, que simule el comportamiento real del mismo, de tal manera que el quadrotor pueda realizar sus movimientos básicos con el mínimo error posible. Para realizar dicho modelo matemático se consideró al quadrotor como un cuerpo rígido de seis grados de libertad en donde el sistema es dividido en coordenadas traslacionales y rotacionales al manejar una técnica para la modelación, mediante las ecuaciones de Euler-Lagrange, y así obtener la función de transferencia, expresada en las plantas del modelo dinámico que describe el comportamiento del quadrotor. La dinámica rotacional del VANT fue definida por los principales momentos de inercia, los cuales fueron hallados en el centro de masa del vehículo, dichos momentos fueron estimados a través del software de entorno CAD Solidworks. Para ello, el quadrotor se ensambló allí con el mínimo de partes posibles y luego el diseño se exportó a Simulink para complementar los resultados de la simulación con una animación en 3D del movimiento. Al diseño de la estructura se le implementó una estrategia de control que estabiliza las plantas ya descritas y se corroboró el funcionamiento del sistema al aplicar al mismo, perturbaciones externas como lo son las ráfagas de viento y masas variables que puedan producir inestabilidad durante el vuelo, logrando que ante este tipo de señales el sistema reaccione de forma controlada. En los resultados se observó que la simulación de una ráfaga de viento en donde el VANT cambio su posición en los ejes de desplazamiento horizontal, este mismo logró llegar nuevamente a su posición de referencia en menos de doce (12) segundos. Lo anterior constituye una importante aplicación de la dinámica rotacional del Vehículo Aéreo No Tripulado, al utilizar Simulink y la librería Simscape Multibody en conjunto con Solidworks, lográndose una herramienta de gran interés y por ende un aporte significativo para el estudio de los VANT, dando posibilidad del uso de una herramienta práctica para el diseño de quadrotores, enfocados en diferentes aplicaciones, tales como la agricultura de precisión.

Abstract: Background: The patellofemoral articulation is a biomechanical system susceptible to accelerated wear, affecting 25% of women. Currently, the treatment of osteoarthrosis Patelofermoral has resurfaced thanks to the creation of anatomical and biomechanically appropriate systems, with precise indications, earlier stages and with a better functional result. Material and methods: A cohort of 24 patients was analyzed during the period from 2010 to 2012, treated with a resurfacing prostheses HemiCap Patello Femoral Resurf (Franklin MA, USA), placed by 2 surgeons. Patients were assessed preoperatively and 2, 4, 6, 12, 18, 24 months postoperative with the Knee Society Score. Results: Twenty-four patients with follow-up of 2 years on average were included. 87.5% were women, an average age of 62 years (45-80 years); an average of 29.5 of body mass index, the right laterality predominated in 54%. An improvement in KSS scale results was observed: in clinical appearance there was an improvement of 35.2% and the functional scale 41.62%. Only two patients were revised by complications of functional limitation, treated one with manipulation under anesthesia and the other with arthroscopic adhesion lysis. Conclusion: The patellofemoral prosthesis is an option as a treatment for isolated patellofemoral arthrosis, since the two-year survival rate is good, providing pain relief and improving knee functionality; However, more follow-up time will be required to evaluate the end result of this implant.

Resumen: Antecedentes: La articulación patelofemoral (PF) es un sistema biomecánico susceptible a desgaste acelerado, afecta a 25% de las mujeres. Actualmente, el tratamiento de la osteoartrosis patelofemoral (OAPF) ha resurgido gracias a la creación de sistemas anatómicos y biomecánicamente adecuados, con indicaciones precisas, estadios más tempranos y con mejor resultado funcional. Material y métodos: Se analizó una cohorte de 24 pacientes durante el período de 2010 a 2012, tratados con prótesis de resuperficialización patelofemoral (PPF) HemiCap Patelofemoral Resurf (Franklin MA, EUA), colocadas por dos cirujanos. Se evaluaron los pacientes prequirúrgicos y a los dos, cuatro, seis, 12, 18, 24 meses postquirúrgicos con la escala Knee Society Score (KSS). Resultados: Se incluyeron 24 pacientes con seguimiento de dos años en promedio. En 87.5% fueron mujeres, edad promedio de 62 años (45-80 años); una media de 29.5 de índice de masa corporal (IMC), la lateralidad derecha predominó en 54%. Se observó una mejoría en los resultados de la escala KSS: en el aspecto clínico hubo una mejoría de 35.2% y en la escala funcional de 41.62%. Sólo dos pacientes fueron reintervenidos por complicaciones de limitación funcional, uno de ellos tratado con manipulación bajo anestesia y el otro con liberación artroscópica de adherencias. Conclusión: La PPF es una opción como tratamiento de AOPF aislada, pues la tasa de supervivencia a dos años es buena, proporciona alivio del dolor y mejoría en funcionalidad de la rodilla; sin embargo, se requerirá mayor tiempo de seguimiento para evaluar el resultado final de este implante.

Abstract: We read the article; Delayed interval delivery or asynchronous birth of the second twin: a case report with a good outcome neonatal, published in the Ginecol Obstet Mex. 2019;87(7):475-482. Doi: https://doi.org/10.24245/gom. v87i7.3122, with great interest. Although, the Hernández-Pérez et al, mentioned that during their successful delayed interval delivery (DID) management and after delivery of the first twin they performed a cervical fence or cerclage to prolong the gestation of the second twin. Many previous studies mentioned that the use of the cervical cerclage during DID associated with increased risk of infection and did not improve the survival of the second twin. Hernández-Pérez et al, mentioned that the protocols associated with this type of births are varied and we agree with Hernández-Pérez et al that there is no validated or standard medical protocol for management of such cases. We recently suggested protocol which may be helpful for management of DID and such cases and for the readers (Doi: 10.4103/jfmpc.jfmpc_5_19).

RESUMO: As culturas de cobertura desempenham um papel importante na agricultura sustentável, uma vez que reduzem a erosão do solo, favorecem a incorporação de nitrogênio por este e reduzem ou modificam a comunidade de ervas daninhas. A fim de avaliar as mudanças relacionadas ao cultivo e à incorporação de crotalária (Crotalaria juncea L.1753) na comunidade de ervas daninhas presentes no solo comumente cultivado com cana-de-açúcar, cultivo agroindustrial de importância vital na região Chontalpa, Tabasco, foi realizado um experimento que incluiu o ciclo de cultivo e a incorporação de fitomassa seca da referida cobertura. Os tratamentos incluíram três níveis de fertilização e dois controles, as parcelas do primeiro foram intercaladas com as dos tratamentos, enquanto que o segundo foi colocado externamente, com o objetivo de evitar o efeito de sombreamento da crotalária. Foram realizadas amostragens mensais, cujos dados permitiram calcular os índices de diversidade e valor de importância (IVI) das plantas daninhas, além da produção seca de fitomassa. Os resultados demonstraram que a fertilização não teve influência na composição, diversidade e importância das ervas daninhas, fatores que se relacionaram mais com a estação das chuvas, período em que foi realizada a pesquisa com o cultivo da crotalária, seu corte e incorporação ao solo. Embora a família mais bem representada tenha sido Euphorbiaceae, suas espécies não estiveram entre as mais importantes da comunidade em que se destacaram Cyperus rotundus L. 1753, Lindernia crustacea (L.) F. Muell. 1882, Scleria setuloso-ciliata Boeckeler 1882, Ageratum houstonianum Mill, 1768 e Acmella repens (Walter) Rich. 1807. A biomassa seca das plantas daninhas apresentou diferenças estatísticas entre as parcelas com e sem crotalária, sendo muito menor nos controles; no entanto, a produção total de fitomassa seca foi extremamente maior nas cultivadas, evidenciando o valor do uso dessa espécie como adubo verde.

ABSTRACT: Cover crops play an important role in sustainable agriculture, as they decrease soil erosion, promote the incorporation of nitrogen into the soil and reduce or modify weed communities. Aiming at evaluating the changes related to the cultivation and incorporation of sunn crotalaria (Crotalaria juncea L.1753) in a weed community of a soil cultivated with sugarcane, an agro-industrial crop of vital importance to La Chontalpa region, Tabasco, Mexico, an experiment encompassing the cultivation cycle and the incorporation of the dry phytomass of this cover crop was carried out. The treatments included three levels of fertilization and two controls, the plots of the first control were interspersed with those of the treatments, while the second control was placed outside, in order to avoid the shade effect caused by crotalaria. Sampling was carried out monthly, and the data obtained from samplings allowed the calculation of weed diversity and importance value (IVI) indexes, in addition to dry phytomass production values. The results showed that the fertilization did not exert any influence on the composition, diversity or importance of the weeds, factors that were more related to the rainy season, period in which the research on the cultivation, cutting and incorporation of crotalaria into the soil was performed. Although the best represented family was Euphorbiaceae, its species were not among the most important in the community in which Cyperus rotundus L. 1753, Lindernia crustacea (L.) F. Muell. 1882, Scleria setuloso-ciliata Boeckeler 1882, Ageratum houstonianum Mill, 1768 and Acmella repens (Walter) Rich. 1807 stood out. The dry biomass of the weeds showed statistical differences between the plots with and without crotalaria, considering that lower values were observed in the control groups; however, the total dry phytomass production was extremely higher in the cultivated plots, highlighting the importance of using this species as green manure.