Metaheuristic Approach to Probabilistic Aircraft Conflict Detection and Resolution Considering Ensemble Prediction Systems

International audienceThis paper presents a methodology to tackle theproblem of strategic aircraft conflict detection and resolution, upto 60 minutes in advance, considering wind and temperatureuncertainties. The problem of hundreds of en-route aircraftflying multi-segmented 2D trajectories is considered. The weatheruncertainty is retrieved from Ensemble Prediction Systems. Theconflict detection is based on ensemble trajectory prediction,and is performed using an efficient grid-based procedure. Ametaheuristic approach is developed to solve the conflicts, basedon simulated annealing, which generates resolution trajectoriesby modifying the location of the route waypoints (vectoring),with the aim of lowering the probabilities of the conflicts whilealso minimising the deviation from the nominal paths. Realisticapplications in scenarios with different traffic densities arepresented

Fall risk detection mechanism in the elderly, based on electromyographic signals, through the use of artificial intelligence

Introduction: The tests used to classify older adults at risk of falls are questioned in literature. Tools from the field of artificial intelligence are an alternative to classify older adults more precisely. Objective: To identify the risk of falls in the elderly through electromyographic signals of the lower limb, using tools from the field of artificial intelligence. Methods: A descriptive study design was used. The unit of analysis was made up of 32 older adults (16 with and 16 without risk of falls). The electrical activity of the lower limb muscles was recorded during the functional walking gesture. The cycles obtained were divided into training and validation sets, and then from the amplitude variable, select attributes using the Weka software. Finally, the Support Vector Machines (SVM) classifier was implemented. Results: A classifier of two classes (elderly adults with and without risk of falls) based on SVM was built, whose performance was: Kappa index 0.97 (almost perfect agreement strength), sensitivity 97%, specificity 100%. Conclusions: The SVM artificial intelligence technique applied to the analysis of lower limb electromyographic signals during walking can be considered a precision tool of diagnostic, monitoring and follow-up for older adults with and without risk of falls

Caracterización productiva y socioeconómica del sistema de producción ovina, en un área natural protegida de México

Ante el incremento de la presencia humana y sus actividades productivas en áreas naturales protegidas, se planteó el objetivo de caracterizar el sistema de producción ovina, en el Nevado de Toluca, con información agrícola, socioeconómica y uso de los recursos de pastoreo. Un total de 162 productores fueron entrevistados, se analizaron 25 variables con estadística multivariada y univariada. Mediante análisis de componentes principales se obtuvieron seis factores que explican el 71 % de la varianza. El análisis cluster permitió identificar tres grupos de productores: pequeños (28 %), intermedios (35 %) y capitalizados (6 %), diferenciados por el número de animales, superficie cultivada e ingresos (P0.05) y se encontró que los rebaños aportan menos del 30 % del ingreso familiar. El 58 % de los rebaños ingresa al bosque, para realizar pastoreo circulante, pero el 60 % se maneja semi-estabulado. Se concluye que la producción del sistema no depende de la capitalización del productor, pero el rebaño es esencial en la economía familiar, y el manejo de los animales es compatible con los esfuerzos de conservación del área natural protegida

HIV-1 Nef Targets HDAC6 to Assure Viral Production and Virus Infection

HIV Nef is a central auxiliary protein in HIV infection and pathogenesis. Our results indicate that HDAC6 promotes the aggresome/autophagic degradation of the viral polyprotein Pr55Gag to inhibit HIV-1 production. Nef counteracts this antiviral activity of HDAC6 by inducing its degradation and subsequently stabilizing Pr55Gag and Vif viral proteins. Nef appears to neutralize HDAC6 by an acidic/endosomal-lysosomal processing and does not need the downregulation function, since data obtained with the non-associated cell-surface Nef-G2A mutant – the cytoplasmic location of HDAC6 – together with studies with chemical inhibitors and other Nef mutants, point to this direction. Hence, the polyproline rich region P72xxP75 (69–77 aa) and the di-Leucin motif in the Nef-ExxxLL160-165 sequence of Nef, appear to be responsible for HDAC6 clearance and, therefore, required for this novel Nef proviral function. Nef and Nef-G2A co-immunoprecipitate with HDAC6, whereas the Nef-PPAA mutant showed a reduced interaction with the anti-HIV-1 enzyme. Thus, the P72xxP75 motif appears to be responsible, directly or indirectly, for the interaction of Nef with HDAC6. Remarkably, by neutralizing HDAC6, Nef assures Pr55Gag location and aggregation at plasma membrane, as observed by TIRFM, promotes viral egress, and enhances the infectivity of viral particles. Consequently, our results suggest that HDAC6 acts as an anti-HIV-1 restriction factor, limiting viral production and infection by targeting Pr55Gag and Vif. This function is counteracted by functional HIV-1 Nef, in order to assure viral production and infection capacities. The interplay between HIV-1 Nef and cellular HDAC6 may determine viral infection and pathogenesis, representing both molecules as key targets to battling HIV

Fall risk detection mechanism in the elderly, based on electromyographic signals, through the use of artificial intelligence

Introduction: The tests used to classify older adults at risk of falls are questioned in literature. Tools from the field of artificial intelligence are an alternative to classify older adults more precisely. Objective: To identify the risk of falls in the elderly through electromyographic signals of the lower limb, using tools from the field of artificial intelligence. Methods: A descriptive study design was used. The unit of analysis was made up of 32 older adults (16 with and 16 without risk of falls). The electrical activity of the lower limb muscles was recorded during the functional walking gesture. The cycles obtained were divided into training and validation sets, and then from the amplitude variable, select attributes using the Weka software. Finally, the Support Vector Machines (SVM) classifier was implemented. Results: A classifier of two classes (elderly adults with and without risk of falls) based on SVM was built, whose performance was: Kappa index 0.97 (almost perfect agreement strength), sensitivity 97%, specificity 100%. Conclusions: The SVM artificial intelligence technique applied to the analysis of lower limb electromyographic signals during walking can be considered a precision tool of diagnostic, monitoring and follow-up for older adults with and without risk of falls

Implementación de una estrategia basada en métodos teóricocomputacionales para la búsqueda y diseño de nuevos inhibidores en la enzima ureasa de Helicobacter pylori

89 p.El metabolismo del nitrógeno es fundamental para un adecuado estado de salud en los seres vivos. Además, el nitrógeno de desecho residual producido por el catabolismo de los aminoácidos es excretado como urea por el riñón. Esta molécula de desecho en los mamíferos es clave para el metabolismo en plantas, hongos y bacterias, ya que estos hidrolizan la urea en amonio para conseguir trazas de nitrógeno esenciales para su desarrollo. Para estas formas de vida, la enzima ureasa dependiente de níquel permite hidrolizar la urea y formar amonio. Por otro lado, la urea es utilizada como fertilizante en la agricultura, debido a su rico contenido de nitrógeno. Las enzimas ureasa de diversos microorganismos distribuidos en el suelo hidrolizan los fertilizantes a base de urea, generando amoníaco que es volatilizado al medio ambiente y finalmente perdido. Esta pérdida de nitrógeno genera una reducción en los rendimientos de cultivo afectando a la economía en la agricultura. Además, la liberación de amoniaco provoca graves consecuencias medioambientales como lluvia ácida y gases de efecto invernadero. La combinación de inhibidores de ureasa (IU) con fertilizantes a base de urea ha surgido como una opción viable para disminuir la pérdida de nitrógeno, al inhibir la actividad catalítica de las enzimas ureolíticas distribuidas en el suelo. Desde otro punto de vista, actualmente se estima que el 50% de la población mundial está infectada por Helicobacter pylori (H. pylori). En el caso de Chile, la tasa de infección es aún mayor, llegando alrededor de 70%. H. pylori es la bacteria ureolítica más patogénica para el ser humano, ya que tiene una rápida adaptación para sobrevivir en diferentes ambientes, incluso pudiendo subsistir en ambientes ácidos como el estómago. Una vez que esta bacteria ha colonizado el cuerpo, puede provocar numerosas patologías, entre ellas cáncer. El actual tratamiento consiste en antibióticos de amplio espectro. Sin embargo, H. pylori ha generado resistencia a estos fármacos de forma progresiva, por lo que la eficacia de la terapia está disminuyendo drásticamente. Además, este tipo de tratamiento genera efectos secundarios. De este modo, han surgido nuevas estrategias terapéuticas que consisten en el uso de IU. Numerosos esfuerzos están centrados en la búsqueda de nuevos inhibidores de ureasa de H. pylori, aquí denominada HpU, que sean potentes y selectivos a la vez, para que se pueda establecer una terapia eficaz para erradicar las infecciones por esta bacteria. Esta tesis se centró en implementar un protocolo basado en el método de Cribado Virtual, específicamente en dos sus variantes: Cribado Virtual Basado en Estructura y Cribado Virtual Basado en Farmacóforo. Estas técnicas permitieron realizar una búsqueda en la base de datos de compuestos ZINC15 que posee una alta dimensionalidad. La metodología consistió en aplicar filtros sucesivos, entre los que se encuentran: generar un filtrado a la base de datos mediante reglas farmacocinéticas y fisicoquímicas, crear hipótesis de farmacóforos basados en núcleos de cumarinas, realizar estudios de acoplamiento molecular mediante diferentes algoritmos y por último, realizar cálculos de energía libre de unión a los complejos proteína-ligando, con el objetivo de seleccionar un número limitado de compuestos candidatos que tengan una mejor afinidad de unión a la enzima HpU. // ABSTRACT: The nitrogen metabolism is fundamental for an adequate state of health in living beings. Also, the nitrogen residual waste produced by the catabolism of amino acids is excreted as urea by the kidney. This waste molecule in mammals is key to metabolism in plants, fungi and bacteria, as they hydrolyze urea into ammonium to obtain trace amounts of nitrogen that is essential for their development. For these life forms, the nickel-dependent enzyme urease allows urea to be hydrolyzed to form ammonium. On the other hand, urea is used as a fertilizer in agriculture, because of its rich nitrogen content. Urease enzymes from various microorganisms distributed in the soil hydrolyze urea-based fertilizers, generating ammonia that is volatilized into the environment and finally lost. This loss of nitrogen generates a reduction in crop yields, affecting the economics of agriculture. In addition, the release of ammonia causes serious environmental consequences such as acid rain and greenhouse gases. The combination of urease inhibitors (UI) with urea-based fertilizers has emerged as a viable option to reduce nitrogen loss by inhibiting the catalytic activity of ureolytic enzymes distributed in the soil. From another point of view, it is currently estimated that 50% of the world's population is infected by Helicobacter pylori (H. pylori). In the case of Chile, the infection rate is even higher, reaching around 70%. H. pylori is the most pathogenic ureolytic bacterium for humans, as it has a rapid adaptation to survive in different environments, even being able to survive in acidic ones such as the stomach. Once this bacterium has colonized the body, it can cause numerous pathologies, including cancer. Current treatment consists of broad-spectrum antibiotics. However, H. pylori has generated resistance to these drugs, so the efficacy of the therapy is drastically decreasing. In addition, this type of treatment generates side effects. In this way, new therapeutic strategies have emerged that consist in the use of UI. Numerous efforts are focused on the search for new H. pylori urease inhibitors, here called HpU, that are potent and selective, so that an effective therapy can be established to eradicate infections by this bacterium. This thesis was focused in the implementation of a protocol based on the Virtual Screening method. Specifically in two of its variants: Structure-Based Virtual Screening and Pharmacophore-Based Virtual Screening. These techniques allowed a search to be carried out in the ZINC15 compound database, which has a high dimensionality. The methodology consisted of applying successive filters, generating a filtering to the database using pharmacokinetic and physicochemical rules, creating pharmacophore hypotheses based on coumarin nuclei, performing molecular docking studies using different algorithms and finally, performing calculations of free energy of binding to protein-ligand complexes, with the objective of selecting a limited number of candidate compounds that have a better binding affinity to the HpU enzyme

Capillary refill time response to a fluid challenge or a vasopressor test:an observational, proof-of-concept study

Background: Several studies have validated capillary refill time (CRT) as a marker of tissue hypoperfusion, and recent guidelines recommend CRT monitoring during septic shock resuscitation. Therefore, it is relevant to further explore its kinetics of response to short-term hemodynamic interventions with fluids or vasopressors. A couple of previous studies explored the impact of a fluid bolus on CRT, but little is known about the impact of norepinephrine on CRT when aiming at a higher mean arterial pressure (MAP) target in septic shock. We designed this observational study to further evaluate the effect of a fluid challenge (FC) and a vasopressor test (VPT) on CRT in septic shock patients with abnormal CRT after initial resuscitation. Our purpose was to determine the effects of a FC in fluid-responsive patients, and of a VPT aimed at a higher MAP target in chronically hypertensive fluid-unresponsive patients on the direction and magnitude of CRT response. Methods: Thirty-four septic shock patients were included. Fluid responsiveness was assessed at baseline, and a FC (500 ml/30 mins) was administered in 9 fluid-responsive patients. A VPT was performed in 25 patients by increasing norepinephrine dose to reach a MAP to 80–85 mmHg for 30 min. Patients shared a multimodal perfusion and hemodynamic monitoring protocol with assessments at at least two time-points (baseline, and at the end of interventions).Results: CRT decreased significantly with both tests (from 5 [3.5–7.6] to 4 [2.4–5.1] sec, p = 0.008 after the FC; and from 4.0 [3.3–5.6] to 3 [2.6 -5] sec, p = 0.03 after the VPT. A CRT-response was observed in 7/9 patients after the FC, and in 14/25 pts after tobjehe VPT, but CRT deteriorated in 4 patients on this latter group, all of them receiving a concomitant low-dose vasopressin. Conclusions: Our findings support that fluid boluses may improve CRT or produce neutral effects in fluid-responsive septic shock patients with persistent hypoperfusion. Conversely, raising NE doses to target a higher MAP in previously hypertensive patients elicits a more heterogeneous response, improving CRT in the majority, but deteriorating skin perfusion in some patients, a fact that deserves further research.</p

Capillary refill time response to a fluid challenge or a vasopressor test:an observational, proof-of-concept study

Background: Several studies have validated capillary refill time (CRT) as a marker of tissue hypoperfusion, and recent guidelines recommend CRT monitoring during septic shock resuscitation. Therefore, it is relevant to further explore its kinetics of response to short-term hemodynamic interventions with fluids or vasopressors. A couple of previous studies explored the impact of a fluid bolus on CRT, but little is known about the impact of norepinephrine on CRT when aiming at a higher mean arterial pressure (MAP) target in septic shock. We designed this observational study to further evaluate the effect of a fluid challenge (FC) and a vasopressor test (VPT) on CRT in septic shock patients with abnormal CRT after initial resuscitation. Our purpose was to determine the effects of a FC in fluid-responsive patients, and of a VPT aimed at a higher MAP target in chronically hypertensive fluid-unresponsive patients on the direction and magnitude of CRT response. Methods: Thirty-four septic shock patients were included. Fluid responsiveness was assessed at baseline, and a FC (500 ml/30 mins) was administered in 9 fluid-responsive patients. A VPT was performed in 25 patients by increasing norepinephrine dose to reach a MAP to 80–85 mmHg for 30 min. Patients shared a multimodal perfusion and hemodynamic monitoring protocol with assessments at at least two time-points (baseline, and at the end of interventions).Results: CRT decreased significantly with both tests (from 5 [3.5–7.6] to 4 [2.4–5.1] sec, p = 0.008 after the FC; and from 4.0 [3.3–5.6] to 3 [2.6 -5] sec, p = 0.03 after the VPT. A CRT-response was observed in 7/9 patients after the FC, and in 14/25 pts after tobjehe VPT, but CRT deteriorated in 4 patients on this latter group, all of them receiving a concomitant low-dose vasopressin. Conclusions: Our findings support that fluid boluses may improve CRT or produce neutral effects in fluid-responsive septic shock patients with persistent hypoperfusion. Conversely, raising NE doses to target a higher MAP in previously hypertensive patients elicits a more heterogeneous response, improving CRT in the majority, but deteriorating skin perfusion in some patients, a fact that deserves further research.</p

Potencial productivo y dinamica de tallos de dos brachiarias a edades de rebrote en otoño: Productive potential and stem dynamics of two brachiarias species at regrowth ages in autumn

La estacionalidad y la frecuencia de cosecha tienen un efecto en la tasa de rebrote en los pastos y pueden disminuir el porcentaje de senescencia y descomposición del forraje, por lo tanto, influyen en el rendimiento, en la calidad y la persistencia de la pradera. El objetivo fue evaluar el potencial productivo y dinámica de tallos de los ecotipos Insurgente (Brachiaria brizantha Hochst. Stapf Cv. Insurgente) y Mulato (Brachiaria hibrido Cv. Mulato II) en tres periodos de corte (21, 42, y 63 días) en Otoño. En el Campus Tuxpan de la Facultad de Ciencias Agropecuarias y Ambientales, de Iguala, Gro. Las variables evaluadas fueron: rendimiento de forraje (kg MS ha-1), producción de componentes morfológicos (HOJA Y TALLO), relación hoja tallo (H:T), densidad poblacional (DPT), tasa de aparición de tallos (TAT), tasa de muerte de tallos (TMT), tasa de sobrevivencia de tallos (TST) e índice de estabilidad de tallos (IET), Se utilizó un diseño de bloques completamente al azar con arreglo bifactorial (Factor 1: Brachiarias, Factor 2: periodos de corte). Los datos se analizaron con el procedimiento ANOVA del paquete estadístico SAS® versión 9.2 para Windows®. La comparación de medias se realizó con la prueba de “t” de “Student” (P&lt;0.05). La producción total de materia seca (4392.7 Kg MS ha-1), la de hoja (3084.8 Kg MS ha-1), la tasa de crecimiento (209.17 Kg MS ha-1) y la relación hoja tallo (4.2943 Kg MS kg-1) fueron afectados por los periodos de corte (P &lt;0001) y por los ecotipos, el Mulato presentó los valores más altos. La mayor producción de hoja, tallo y total de materia seca se presentó en el tercer periodo de corte y de igual forma la tasa de crecimiento. En la dinámica de tallos los ecotipos no presentaron diferencias, los periodos de corte si afectaron a la TAT (81.87 tallos m2) y al IET (1.79), en los que el periodo de corte 1 presento los valores más altos. &nbsp

Uso de la Wii Balance Board como mecanismo de reconocimiento y clasificación del riesgo de caídas en el adulto mayor

Introduction: In clinical practice, the functional tests used to assess the risk of falls require precision techniques and elements that avoid subjectivity. The use of the Wii Balance Board (WBB) is an alternative to the above, since it is an inexpensive, portable tool that allows extracting variables that are related to the phenomenon under study.Objective: To classify the variables derived from the center of pressure (CoP) during the evaluation of postural control through the WBB, in older adults with and without risk of falls.Methods: A descriptive research design was used. A total of 40 older adults were studied, 20 with and 20 without risk of falls. Postural control was evaluated using the WBB, extracting kinetic and kinematic variables, which allowed the implementation of an attribute selector and the SVM algorithm (SVMs, Support Vector Machines), identifying older adults at risk of falls.Results: The variables that best allow us to classify older adults with and without risk of falling were speed, displacement and mean force. A two-class classifier was built, whose best performance was the Kappa index 0.95 (almost perfect agreement strength), 98% sensitivity, and 100% specificity.Conclusions: The use of WBB can be considered a low-cost alternative for the evaluation of the risk of falls in older adults. &nbsp;Introducción: En la práctica clínica las pruebas funcionales utilizadas para evaluar el riesgo de caídas requieren de técnicas y elementos de precisión que eviten la subjetividad. El uso de la Wii Balance Board (WBB) es una alternativa ante lo expuesto, ya que es una herramienta económica, portátil y que permite extraer variables que se relacionan con el fenómeno en estudio. Objetivo: Clasificar las variables derivadas del centro de presión (CoP) durante la evaluación del control postural por medio de la WBB, en adultos mayores con y sin riesgo de caídas. Métodos: Se utilizó un diseño de investigación descriptivo. Se estudió a 40 adultos mayores, 20 con y 20 sin riesgo de caídas. El control postural fue evaluado mediante la WBB, extrayendo variables cinéticas y cinemáticas, que permitieron implementar un selector de atributos y el algoritmo SVM (SVMs, del inglés Support Vector Machines), identificando a los adultos mayores con riesgo de caídas. Resultados: Las variables que mejor permiten clasificar a los adultos mayores con y sin riesgo de caída fueron la velocidad, desplazamiento y fuerza media. Se construyó un clasificador de dos clases, cuyo mejor desempeño fue el índice Kappa 0,95 (fuerza de concordancia casi perfecta), sensibilidad 98%, y especificidad 100%. Conclusiones: El uso de WBB puede ser considerada una alternativa de bajo costo para la evaluación del riesgo de caídas en adultos mayores