Segmentación de imágenes NIR de iris empleando técnicas de deep learning

Tesis (Ingeniero Civil Informático)En los tiempos actuales la seguridad informática es un tópico recurrente en sectores de salud, gubernamentales, bancarios, aeropuertos internacionales, marketing basado en internet, entre otros. Por ello la identificación correcta y fiable de una persona que requiere de estos servicios es crucial al momento de tratarse de seguridad. Dentro de las técnicas de seguridad más utilizadas podemos encontrar el uso de contraseñas escritas, credenciales de identificación, firmas, entre otras, lo cual puede representar un eventual riesgo si las contraseñas se olvidan, las credenciales se extravían o cuando las firmas son falsificadas. Dado lo mencionado, la biometría representa una respuesta de carácter importante gracias al rendimiento y nivel de seguridad que provee. Por definición, biometría se refiere al estudio de la identificación de personas basado en sus rasgos físicos o comportamientos biológicos. Entre los rasgos biométricos se pueden incluir la escritura a mano, la manera de caminar o firmas escritas, mientras que los rasgos físicos comunes son el rostro, huellas dactilares, venas, retina, el iris entre otros. El iris es considerado como una modalidad biométrica muy interesante debido a su unicidad, estabilidad a través del tiempo y por su protección ante degradaciones externas puesto que es un órgano interno. Todos estos factores conducen a una precisión de identificación notablemente alta. Aún así, el rendimiento de un sistema de reconocimiento de iris es un problema crítico cuando la adquisición del iris está menos restringida frente a factores como el reflejo de luz natural sobre el iris u otras oclusiones. Tales problemas, cuando el iris se adquiere en situaciones más realistas, están en el centro de trabajos de investigación. Luego, la tarea de segmentación es importante puesto que representa la parte fundamental de un sistema de reconocimiento de iris ya que una segmentación deficiente puede generar problemas más tarde al momento de realizar la comparación de plantillas de iris comprometiendo el desempeño final del sistema de reconocimiento de iris

Evaluación del corte y diferentes aplicaciones de diésel para el control de huizache (Acacia farnesiana) en el estado deVeracruz

Con el objetivo de encontrar alternativas para el control dé Huizache, se elaboró el presente estudio, en el que se realizaron ciertos tratamientos

Control del zacate carretero (Bothriochloa pertusa) con dos herbicidas y dos métodos de aplicación en el sur de Tamaulipas

Se realizó un estudio con el objeto de controlar un zacate considerado como indeseable en praderas cultivadas tropicales

On the feasibility of Bluetooth, Zigbee and IEEE 802.15.4 technologies on board high speed trains

This paper studies the feasibility of using low-power wireless technologies such as Bluetooth, IEEE 802.15.4 and ZigBee in high-speed railway scenarios that involve bidirectional land-to-train communication. The presented results have been obtained through experimental tests conducted at the high-speed railway line connecting Madrid to Barcelona. A multiplatform communication system has been installed in a high-speed train, circulating at velocities up to 300 km/h, whereas autonomous devices have been disseminated along of the railway path to communicate with the onboard devices. The conclusions drawn from this work will be used as guidelines for the future implementation of autonomous communication platforms for high-speed rail connectivity.Postprint (author’s final draft

COVID-19 y su impacto en el miocardio

77 p.Nuestra comprensión del impacto de COVID-19 a nivel cardiovascular se encuentra en progreso. La aparición de investigaciones, reportes de casos clínicos e informes que relacionan directa o indirectamente la lesión miocárdica por SARSCoV- 2 mediada por ACE-2, hipoxia, alteración de la microcirculación, aumento de la coagulación y trombogénesis y la tormenta de citocinas, contribuyen a la comprensión de complicaciones cardiovasculares asociadas al agente viral, donde se denota la presencia de biomarcadores cardiovasculares alterados. 1. PROPÓSITO Revisar, organizar e identificar los mecanismos fisiopatológicos involucrados en el avance clínico de este virus, de tal manera de dejar en evidencia la existencia de la vinculación de SARS-Cov-2 y su impacto a nivel del miocardio. 2. METODOLOGÍA Revisión y selección en base a criterios de calidad y adecuación a los objetivos de la revisión asociada a COVID-19 y su impacto cardiovascular en metabuscador PubMed y otras fuentes bibliográficas. 3. CONCLUSIÓN Aún se requiere mayor evidencia clínica y experimental que permita esclarecer totalmente los eventos asociados al desarrollo de patologías cardiovasculares. Sin embargo, la evidencia clínica ha mostrado la existencia de una asociación entre la infección por SARS-CoV-2 y la lesión o daño al miocardio

Preparing for the incalculable

El texto traducido presenta una reflexión de largo aliento alrededor de la relación deconstrucción y educación.&nbsp

Extraction of Mn from Black Copper Using Iron Oxides from Tailings and Fe2+ as Reducing Agents in Acid Medium

Exotic type deposits include several species of minerals, such as atacamite, chrysocolla, copper pitch, and copper wad. Among these, copper pitch and copper wad have considerable concentrations of manganese. However, their non-crystalline and amorphous structure makes it challenging to recover the elements of interest (like Cu or Mn) by conventional hydrometallurgical methods. For this reason, black copper ores are generally not incorporated into the extraction circuits or left unprocessed, whether in stock, leach pads, or waste. Therefore, to dilute MnO2, the use of reducing agents is essential. In the present research, agitated leaching was performed to dissolve Mn of black copper in an acidic medium, comparing the use of ferrous ions and tailings as reducing agents. Two samples of black copper were studied, of high and low grade of Mn, respectively, the latter with a high content of clays. The effect on the reducing agent/black copper ratio and the concentration of sulfuric acid in the system were evaluated. Better results in removing Mn were achieved using the highest-grade black copper sample when working with ferrous ions at a ratio of Fe2+/black copper of 2/1 and 1 mol/L of sulfuric acid. Besides, the low-grade sample induced a significant consumption of H2SO4 due to the high presence of gangue and clays.The authors are grateful for the contribution of the Scientific Equipment Unit- MAINI of the Universidad Católica del Norte for aiding in generating data by automated electronic microscopy QEMSCAN® and for facilitating the chemical analysis of the solutions. We are also grateful to the Altonorte Mining Company for supporting this research and providing slag for this study, and we thank to Marina Vargas Aleuy and María Barraza Bustos of the Universidad Católica del Norte for supporting the experimental tests. Also, we Conicyt Fondecyt 11,171,036 and Centro CRHIAM Project Conicyt/Fondap/15130015. This research received no external fundin

Efecto del encuadre sobre el descuento temporal en jóvenes que consumen alcohol: análisis del dominio

Favorecer la preferencia por beneficios futuros se ha logrado al hacer explícito que los resultados de una elección implican no recibir la alternativa no elegida, hallazgo denominado efecto del cero escondido. Objetivo. El presente estudio evaluó la generalidad del efecto en tareas de descuento por demora en dos dominios (i.e., monetario y sa-lud) con participantes que reportaron consumo de alcohol. Método. Los participantes fueron expuestos a dos tipos de tareas, una con el cero implícito y otra con el cero explícito, esto en ambos dominios y empleando dos recom-pensas de distinta magnitud. Resultados. Los resultados mostraron una tendencia en la que el grado de descuento incrementa en función del consumo de alcohol, al menos para el caso de consecuencias monetarias. Además, se re-plicó el efecto del cero escondido y el efecto de magnitud independientemente del nivel de consumo de alcohol en tareas monetarias. No obstante, ninguno de estos efectos se observó en el dominio de salud con el procedimiento empleado. Adicionalmente, no se observó una asociación sistemática de la tasa de descuento con las consecuencias negativas vinculadas al consumo de alcohol. Conclusiones. Hacer explícito el costo de oportunidad resulta en una disminución de la tasa de descuento de recompensas monetarias, pero se requiere mayor investigación para preci-sar la ausencia del efecto en situaciones que involucran decisiones sobre la saludPreference for delayed rewards has been promoted by making explicit that preference for one alternative implies not receiving the not chosen alternative, a result named the hidden-zero effect. Objective. The present research assessed the generality of the hidden-zero effect in delay discounting tasks in two domains (i.e., monetary and heal-th) in participants that reported alcohol consumption. Method. The participants were exposed to two discounting tasks, one with the implicit zero and one with the explicit zero, using both health and monetary rewards and emplo-ying different amounts. Results. Results showed a tendency to reduce the value of future monetary consequences at higher rate as a function of alcohol drinking. Also, the hidden-zero effect and the magnitude effect were repli-cated in the monetary domain independently of alcohol drinking status. Nevertheless, none of these effects were observed using health outcomes with the actual procedure. Finally, no systematic association between discounting rate and negative consequences derived from alcohol consumption was observed. Conclusions. Making explicit the opportunity cost reduce discounting rate of monetary outcomes, but more research is needed to clarify the absence of effects when deciding about health

Effects of early life exposure to traffic-related air pollution on brain development in juvenile Sprague-Dawley rats

Epidemiological studies link traffic-related air pollution (TRAP) to increased risk for various neurodevelopmental disorders (NDDs); however, there are limited preclinical data demonstrating a causal relationship between TRAP and adverse neurodevelopmental outcomes. Moreover, much of the preclinical literature reports effects of concentrated ambient particles or diesel exhaust that do not recapitulate the complexity of real-world TRAP exposures. To assess the developmental neurotoxicity of more realistic TRAP exposures, we exposed male and female rats during gestation and early postnatal development to TRAP drawn directly from a traffic tunnel in Northern California and delivered to animals in real-time. We compared NDD-relevant neuropathological outcomes at postnatal days 51-55 in TRAP-exposed animals versus control subjects exposed to filtered air. As indicated by immunohistochemical analyses, TRAP significantly increased microglial infiltration in the CA1 hippocampus, but decreased astrogliosis in the dentate gyrus. TRAP exposure had no persistent effect on pro-inflammatory cytokine levels in the male or female brain, but did significantly elevate the anti-inflammatory cytokine IL-10 in females. In male rats, TRAP significantly increased hippocampal neurogenesis, while in females, TRAP increased granule cell layer width. TRAP had no effect on apoptosis in either sex. Magnetic resonance imaging revealed that TRAP-exposed females, but not males, also exhibited decreased lateral ventricular volume, which was correlated with increased granule cell layer width in the hippocampus in females. Collectively, these data indicate that exposure to real-world levels of TRAP during gestation and early postnatal development modulate neurodevelopment, corroborating epidemiological evidence of an association between TRAP exposure and increased risk of NDDs

Insulin Induces Relaxation and Decreases Hydrogen Peroxide-Induced Vasoconstriction in Human Placental Vascular Bed in a Mechanism Mediated by Calcium-Activated Potassium Channels and L-Arginine/Nitric Oxide Pathways

Insulin induces relaxation in umbilical veins, increasing the expression of human amino acid transporter 1 (hCAT-1) and nitric oxide synthesis (NO) in human umbilical vein endothelial cells (HUVECs). Short-term effects of insulin on vasculature have been reported in healthy subjects and cell cultures; however, its mechanisms remain unknown. The aim of this study was to characterize the effect of acute incubation with insulin on the regulation of vascular tone of placental vasculature. HUVECs and chorionic vein rings were isolated from normal pregnancies. The effect of insulin on NO synthesis, L-arginine transport, and hCAT-1 abundance was measured in HUVECs. Isometric tension induced by U46619 (thromboxane A analog) or hydrogen peroxide (HO) were measured in vessels previously incubated 30 min with insulin and/or the following pharmacological inhibitors: tetraethylammonium (KCa channels), iberiotoxin (BKCa channels), genistein (tyrosine kinases), and wortmannin (phosphatidylinositol 3-kinase). Insulin increases L-arginine transport and NO synthesis in HUVECs. In the placenta, this hormone caused relaxation of the chorionic vein, and reduced perfusion pressure in placental cotyledons. In vessels pre-incubated with insulin, the constriction evoked by HO and U46619 was attenuated and the effect on HO-induced constriction was blocked with tetraethylammonium and iberiotoxin, but not with genistein, or wortmannin. Insulin rapidly dilates the placental vasculature through a mechanism involving activity of BKCa channels and L-arginine/NO pathway in endothelial cells. This phenomenon is related to quick increases of hCAT-1 abundance and higher capacity of endothelial cells to take up L-arginine and generate NO