3,774 research outputs found
Cooperative cell motility during tandem locomotion of amoeboid cells.
Streams of migratory cells are initiated by the formation of tandem pairs of cells connected head to tail to which other cells subsequently adhere. The mechanisms regulating the transition from single to streaming cell migration remain elusive, although several molecules have been suggested to be involved. In this work, we investigate the mechanics of the locomotion ofDictyosteliumtandem pairs by analyzing the spatiotemporal evolution of their traction adhesions (TAs). We find that in migrating wild-type tandem pairs, each cell exerts traction forces on stationary sites (∼80% of the time), and the trailing cell reuses the location of the TAs of the leading cell. Both leading and trailing cells form contractile dipoles and synchronize the formation of new frontal TAs with ∼54-s time delay. Cells not expressing the lectin discoidin I or moving on discoidin I-coated substrata form fewer tandems, but the trailing cell still reuses the locations of the TAs of the leading cell, suggesting that discoidin I is not responsible for a possible chemically driven synchronization process. The migration dynamics of the tandems indicate that their TAs' reuse results from the mechanical synchronization of the leading and trailing cells' protrusions and retractions (motility cycles) aided by the cell-cell adhesions
TiO2-Low Band Gap Semiconductor Heterostructures for Water Treatment Using Sunlight-Driven Photocatalysis
Heterogeneous photocatalysis is a promising advanced oxidation process for water purification, given its potential to fully oxidize organic pollutants and to inactivate microorganisms. Due to its versatility and high performance in a broad range of conditions, titanium dioxide (TiO2)-based photocatalysis has been systematically used at laboratory scale to treat water of different quality. Even though TiO2 is an exceptional photocatalyst, its broad band gap value (3.2 eV) makes necessary the use of UV light to achieve the photoactivation. This results in the underutilization of the material in sunlight-driven photocatalysis schemes. In order to overcome this handicap, the synthesis of heterostructures using low band gap semiconductors coupled with TiO2 has brought exceptional materials for visible light-driven photocatalysis. In this chapter, the fundamentals of the synthesis and photoactivation of TiO2-low band gap semiconductor heterostructures are explored. The mechanisms leading to the increase of the photocatalytic activity of such heterostructures are described. A summary of the available data on the photocatalytic performance of TiO2-based heterostructures is presented, in terms of degradation of organic pollutants in water using visible light and sunlight. A comparison of the depuration performance of powdered and thin film heterostructures is given at the end of the chapter
Models for the Assessment of Treatment Improvement: The Ideal and the Feasible
Comparisons of different treatments or production processes are the goals of a significant fraction of applied research. Unsurprisingly, two sample problems play a main role in statistics through natural questions such as. Is the the new treatment significantly better than the old. However, this is only partially answered by some of the usual statistical tools for this task. More importantly, often practitioners are not aware of the real meaning behind these statistical procedures. We analyze these troubles from the point of view of the order between distributions, the stochastic order, showing evidence of the limitations of the usual approaches, paying special attention to the classical comparison of means under the normal model. We discuss the unfeasibility of statistically proving stochastic dominance, but show that it is possible, instead, to gather statistical evidence to conclude that slightly relaxed versions of stochastic dominance hold.Research partially supported by the Spanish Ministerio de Economía y Competitividad y fondos FEDER,
grants MTM2014-56235-C2-1-P and MTM2014-56235-C2-2, and by Consejería de Educación de la Junta de Castilla y León, grant VA212U13
INVESTIGACIÓN APLICADA PARA MANEJO DE RECURSOS NATURALES DEL SOLAR FAMILIAR TROPICAL
Results from applied research in agroecosystems of the Mexican tropics (center of Veracruz) are presented. Starting in 2000, with the participation of the Kellogg Foundation, work has been carried out for the Integral Management of Natural Resources of the Low Tropical Zones, through a Center forLearning and Exchange of Knowledge (Centro de Aprendizaje e Intercambio de Saberes, CAIS), as a demonstrative module and promoter where the producers decided to adopt and adapt technologies that were useful to them. Participative diagnoses began, and from them technologies were designed and operated to use regional materials to build housing, and agricultural, livestock and aquaculture productive units, contributing to the dietary and energetic self-sufficiency. During the time of operation, dozens of workshops have been taught in the CAIS to students, technicians, and groups of producers who currently operate in their communities some of the technologies they learned about.Se presentan resultados de investigación aplicada en agroecosistemas del trópico de México (centro de Veracruz). A partir del año 2000, con la integracion de la Fundación Kellogg se han realizado trabajos para el Manejo Integrado de Recursos Naturales de las Zonas Bajas Trópicales, mediante un Centro de Aprendizaje e Intercambio de Saberes (CAIS), como un módulo demostrativo y motivador donde los productores decidieron la adopción y adaptación de tecnologias que les fueran útiles. Se inició con diagnósticos participativos y a partir de ellos se diseñaron y operaron tecnologías para utilizar materiales regionales para construir viviendas y unidades de producción agropecuária y agroacuícola, lo cual conribuyó a la autosuficiencia alimentaria y energética. En el tiempo de operación, en el CAIS se han impartido decenas de talleres a estudiantes, técnicos y grupos de produtores quienes actualmente operan en sus comunidades algunas de las tecnologias aprendidas
Restauración de la Casa Museo Manuel María Aguilera Patiño por parte de entidades sin fines de lucro
Objetivos generales
1. Lograr la restauración de la Casa Museo
2. Resaltar el valor histórico que posee el inmueble al igual que la importancia que tiene este museo para incrementar el turismo en el distrito de Antón
3. Contribuir a la divulgación de las tradiciones del pueblo antonero y su legado a la fe cristiana bajo la devoción del Santo Cristo de Esquipulas
4. Promover turísticamente al Distrito de Antón e incluirlo dentro de los archivos turísticos de la provincia de Coclé.
5. Mantener vínculos permanentes con las Instituciones Nacionales e Internacionales encargadas de dicha restauración
6. Incrementar de la economía del distrito de Antón
7. Fomentar el interés por el rescate de las tradiciones folklóricas, leyendas, danzas, festividades, gastronomía, etc.
8. Contribuir a encauzar las actividades interdisciplinarias a lo largo del proceso de ejecución del anteproyecto de restauración
9. Contribuir a homologar los niveles de calidad de anteproyecto de restauración presentados en esta investigación.
10. Coadyubar con las autoridades correspondientes para el rescate del patrimonio del Distrito de Antón
Objetivos Específicos
1. Diseñar instrumentos de evaluación, análisis y controles del proyecto de restauración para la Casa Museo Manuel María Aguilera Patiño, y que sean de aplicación nacional
2. Aplicar tales instrumentos a un proyecto de restauración, en este caso la Casa de Museo
3. Establecer un formato de presentación para toda la información suministrada por lo
Predicting COVID-19 progression from diagnosis to recovery or death linking primary care and hospital records in Castilla y León (Spain).
This paper analyses COVID-19 patients' dynamics during the first wave in the region of Castilla y León (Spain) with around 2.4 million inhabitants using multi-state competing risk survival models. From the date registered as the start of the clinical process, it is assumed that a patient can progress through three intermediate states until reaching an absorbing state of recovery or death. Demographic characteristics, epidemiological factors such as the time of infection and previous vaccinations, clinical history, complications during the course of the disease and drug therapy for hospitalised patients are considered as candidate predictors. Regarding risk factors associated with mortality and severity, consistent results with many other studies have been found, such as older age, being male, and chronic diseases. Specifically, the hospitalisation (death) rate for those over 69 is 27.2% (19.8%) versus 5.3% (0.7%) for those under 70, and for males is 14.5%(7%) versus 8.3%(4.6%)for females. Among patients with chronic diseases the highest rates of hospitalisation are 26.1% for diabetes and 26.3% for kidney disease, while the highest death rate is 21.9% for cerebrovascular disease. Moreover, specific predictors for different transitions are given, and estimates of the probability of recovery and death for each patient are provided by the model. Some interesting results obtained are that for patients infected at the end of the period the hazard of transition from hospitalisation to ICU is significatively lower (p < 0.001) and the hazard of transition from hospitalisation to recovery is higher (p < 0.001). For patients previously vaccinated against pneumococcus the hazard of transition to recovery is higher (p < 0.001). Finally, internal validation and calibration of the model are also performed
Classification of oximetry signals using Bayesian neural networks to assist in the detection of obstructive sleep apnoea syndrome
In the present study, multilayer perceptron (MLP) neural networks were applied to help in the diagnosis of obstructive sleep apnoea syndrome (OSAS). Oxygen saturation (SaO2) recordings from nocturnal pulse oximetry were used for this purpose. We performed time and spectral analysis of these signals to extract 14 features related to OSAS. The performance of two different MLP classifiers was compared: maximum likelihood (ML) and Bayesian (BY) MLP networks. A total of 187 subjects suspected of suffering from OSAS took part in the study. Their SaO2 signals were divided into a training set with 74 recordings and a test set with 113 recordings. BY-MLP networks achieved the best performance on the test set with 85.58% accuracy (87.76% sensitivity and 82.39% specificity). These results were substantially better than those provided by ML-MLP networks, which were affected by overfitting and achieved an accuracy of 76.81% (86.42% sensitivity and 62.83% specificity). Our results suggest that the Bayesian framework is preferred to implement our MLP classifiers. The proposed BY-MLP networks could be used for early OSAS detection. They could contribute to overcome the difficulties of nocturnal polysomnography (PSG) and thus reduce the demand for these studies
Monitoring of the arterial pressure in effort. dominant, not dominant arm or both?
Objetivo: evaluar la diferencia de los valores de Presión arterial (PA) entre ambos brazos, medida simultáneamente, durante una prueba de esfuerzo.
Diseño del estudio: estudio transversal. Series de casos. Nivel de evidencia: 3
Material y Métodos: La población se compone de 225 deportistas sanos que realizaron una prueba de esfuerzo en nuestro centro. 128 hombres y 97 mujeres. Edad: 17± 5,5 años.
Resultados: La PA tanto sistólica como diastólica no difiere significativamente entre ambos miembros superiores. No obstante, hemos encontrado casos de variabilidad individual donde la PA predomina en un brazo durante el reposo y en el otro brazo durante el máximo esfuerzo. Los valores de TA son independientes del brazo dominante.
Conclusiones: La posibilidad que el brazo donde predomina la PA de Reposo no coincida durante el máximo esfuerzo, hace necesario, en nuestra opinión, que se mida la PA en ambos miembros superiores durante la prueba de esfuerzoObjective: To evaluate different blood pressure readings between both arms.
Study design: cross-sectional study. Case series. Level of evidence: 3.
Methods: a population of 225 healthy athletes underwent stress tests in our center: 128 males and 97 females. Age range: 17 +/- 5.5 years.
Results: no significant differences in systolic or diastolic blood pressure readings were found between the right or left arm. We did, however, find cases where blood pressure is higher in one arm while resting and in the other arm during maximal exercise. Blood pressure readings were not associated with the dominant arm.
Conclusions: The possibility that the arm in which there is a predominant rest blood pressure does not coincide during maximum stress, makes it necessary, according to our judgment, to measure blood pressure in both upper limbs during stress test
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