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Se realizó un estudio en 130 recién nacidos (RN), 54.61 % fueronvarones y 43.58 % mujeres; el 89.22 % estuvo dentro de las primeras 24 h. Se les sometió a exploración clínica, electrocardiografía (ECG), registro de presión arterial (PA) con sistema Doppler modalidad lineal (Sonicaid) y vibratoria (Arteriosonde) y determinación delípidos. La PA por el método Arteriosonde, el más recomendable, tuvo un promedio para varones de 68.75/38.04 mm. Hg y para mujeres 63.36/35.54 mm Hg; se encontró en el 3.12 % cifras tensionales por encima del percentil 95th (P95). En el ECG se observó SAP en + 46°.88 adelante; SÁQRS en + 141º.2 intermedio; SAT de -30º a + 120° adelante; onda T positiva en 45.38 %, negativa en 27.69 %, bifásica en 26.15 % en V1 V2; se observó T positiva hasta las 30 h.; QTc en 0.408"; QT prolongada en 13.82 %, sin síndrome de muerte súbita. Se encontró cifras promedio de colesterol 109.11mg %, triglicéridos 83.13 mg %, lípidos totales 664.3 mg %, VLDL 20.08 %, LDL 54.59 %, HDL 25.42 %; en el 2.17 % se encontró niveles de lipidos por encima del P95. En conclusión el RN además del APGAR debe ser sometidoa evaluación cardiovascular, ECG, de PA y Lípidos. Los casos con cifras altas de PA y lípidos, merecen seguimiento longituinal y vertical.

Streptomyces is a genus of Gram-positive bacteria with high GC content. It remains attractive for studying and discovering new antibiotics, antifungals, and chemotherapeutics. Streptomyces genomes can contain more than 30 cryptic and expressed biosynthetic gene clusters (BGC) encoding secondary metabolites. In this study, three Streptomyces strains isolated from jungle rhizospheric soil exhibited supernatants that can inhibit sensitive and fluconazole-resistant Candida spp. The genomes of the strains Streptomyces sp. A1, J25, J29 ori2 were sequenced, assembled de novo, and analyzed. The genome assemblies revealed that the size of the genomes was 6.9 Mb, with linear topology and 73.5% GC. A phylogenomic approach identified the strains with high similitudes between 98.5 and 98.7% with Streptomyces albidoflavus SM254 and R-53649 strains, respectively. Pangenomic analysis of eight genomes of S. albidoflavus strains deposited in the Genomes database recognized 4707 core protein orthogroups and 745 abundant accessory and exclusive protein orthogroups, suggesting an open pangenome in this species. The antiSMASH software detected candicidin and surugamide BGC-encoding polyene and octapeptide antifungal secondary metabolites in other S. albidoflavus. CORASON software was used to compare the synteny, and the abundance of genes harbored in the clusters was used. In conclusion, although the three strains belong to the same species, each possesses a distinct genome, as evidenced by the different phenotypes, including antifungal and extracellular enzymatic activities.

The hovering flight of a quadrotor Unmanned Aerial Vehicle (UAV) refers to maintaining the aircraft in a fixed position in the air, without lateral, vertical, or rotational movements, using only the vehicle’s control systems to maintain proper balance in all spatial dimensions. Algorithms and control systems have been developed to continuously adjust motor speeds to counteract deviations from the desired position and achieve effective hovering flight. This paper proposes a set of PID controllers with an integral effect based on the Riemann–Liouville fractional-order approach to improve the hovering flight of a quadrotor UAV. This research innovates by introducing a set of fractional-order PID controllers for UAV hover stability, which offer better adaptability to non-linear dynamics and robustness than traditional PID controllers. Also presented is the development of new performance metrics (MSE, BQC-LR), which allow for more comprehensive control system evaluations. A thorough comparative analysis with conventional control methods demonstrates the superior performance of fractional-order control in real-world simulations. The numerical simulation results show the effectiveness of the proposed Fractional Integral Action PID Controller in the control of UAV hovering flight, while comparative analyses against a classical controller emphasize the benefits of the fractional-order approach in terms of control accuracy.

La importancia que tiene el pensamiento computacional en el desarrollo del pensamiento y aprendizaje de las matemáticas se precisa desde métodos y técnicas utilizados para resolver de forma sistemática y algorítmica operaciones que demandan la automatización de conocimientos ordenados y secuenciales, trasladando cada mecanismo al tratamiento de información referente a instrucciones planteadas en la definición de problemas reales del estudiante. El estudio tiene como propósito analizar el pensamiento computacional versus el pensamiento matemático, mostrando que existe una correlación entre estos, mediante procesos de aprendizaje en estudiantes de bachillerato en niveles de 7 y 9 grado de la Institución Educativa Comunitaria Distrital Manuel Elkin Patarroyo de la ciudad de Barranquilla-Colombia; particularmente se presentan semejanzas, analogías y similitudes que se evidencian, mediante el análisis correlacional entre ambos pensamientos a través de la dimensión cognitiva de los procesos de aprendizaje. El estudio se desarrolló mediante una metodología cuantitativa, método no experimental, corte transversal y alcance explicativo; permitiendo con el cuestionario obtener la información. Los resultados dan cuenta de la coincidencia entre ambos pensamientos, comprobando de forma estadística, la fuerte correlación entre las variables. Se concluye que a medida que se desarrollan procesos de aprendizaje en un pensamiento, implícitamente se generan en el otro.

Alternative recombinant sources of antivenoms have been successfully generated. The application of such strategies requires the characterization of the venoms for the development of specific neutralizing molecules against the toxic components. Five toxic peptides to mammals from the Mexican scorpion Centruroides villegasi were isolated by chromatographic procedures by means of gel filtration on Sephadex G-50, followed by ion-exchange columns on carboxy-methyl-cellulose (CMC) resins and finally purified by high-performance chromatography (HPLC) columns. Their primary structures were determined by Edman degradation. They contain 66 amino acids and are maintained well packed by four disulfide bridges, with molecular mass from 7511.3 to 7750.1 Da. They are all relatively toxic and deadly to mice and show high sequence identity with known peptides that are specific modifiers of the gating mechanisms of Na+ ion channels of type beta-toxin (β-ScTx). They were named Cv1 to Cv5 and used to test their recognition by single-chain variable fragments (scFv) of antibodies, using surface plasmon resonance. Three different scFvs generated in our laboratory (10FG2, HV, LR) were tested for recognizing the various new peptides described here, paving the way for the development of a novel type of scorpion antivenom.

The Organization of American States (hereinafter OAS) is the only setting for dialogue and political meetings of all the countries of the Hemisphere, and in recent years democracy has become a priority objective and value. Therefore, the aim of this article is to analyze the role that the OAS has had and may have in Latin American democracies, through its political commitments and its normative body. It is stated that the capacity of the OAS to promote and defend democracy depends on the existence, or not, of an ideological consensus in the political systems of the region on the priority that this universal value has, and that only with a vocation of greater supranationality will it be able to promote and defend to democracy.

Five peptides were isolated from the venom of the Mexican scorpion Centruroides bonito by chromatographic procedures (molecular weight sieving, ion exchange columns, and HPLC) and were denoted Cbo1 to Cbo5. The first four peptides contain 66 amino acid residues and the last one contains 65 amino acids, stabilized by four disulfide bonds, with a molecular weight spanning from about 7.5 to 7.8 kDa. Four of them are toxic to mice, and their function on human Na+ channels expressed in HEK and CHO cells was verified. One of them (Cbo5) did not show any physiological effects. The ones toxic to mice showed that they are modifiers of the gating mechanism of the channels and belong to the beta type scorpion toxin (β-ScTx), affecting mainly the Nav1.6 channels. A phylogenetic tree analysis of their sequences confirmed the high degree of amino acid similarities with other known bona fide β-ScTx. The envenomation caused by this venom in mice is treated by using commercially horse antivenom available in Mexico. The potential neutralization of the toxic components was evaluated by means of surface plasmon resonance using four antibody fragments (10FG2, HV, LR, and 11F) which have been developed by our group. These antitoxins are antibody fragments of single-chain antibody type, expressed in E. coli and capable of recognizing Cbo1 to Cbo4 toxins to various degrees.

La investigación pretende describir en forma resumida cómo implementar los requisitos establecidos en la norma ISO/IEC 17025:2017, para la competencia de los laboratorios de ensayos con calidad, destacando el contexto del Laboratorio y los elementos básicos del riesgo laboral de acuerdo a las directrices de la norma ISO 31000:2018. Se inicia, con una reseña histórica sobre la evolución de la calidad y su importancia en los laboratorios de ensayos, se describen los componentes básicos del contexto del laboratorio haciendo énfasis en los factores externos e internos. Se abordan los aspectos necesarios de la gestión del riesgo resumido a través de un diagrama de flujo, destacando la identificación del riesgo, análisis, valoración y el tratamiento. Luego se hace una descripción sucinta de las exigencias por competitividad de los laboratorios, priorizando el enfoque de proceso y la gestión del riesgo que, de forma explícita, se encuentra a lo largo del contenido de la norma. Finalmente, se discute la importancia del uso del Sistema de Gestión de la Información en Laboratorios (LIMS) y la inteligencia artificial, como herramienta de garantía de la productividad y calidad en los resultados de los clientes.

This paper proposes a modification of a Sliding Mode Classical Observer (SMCO) to adapt it to the fractional approach. This adaptation involves using a set of definitions based on fractional calculus theory, particularly the approach developed by Riemann–Liouville, resulting in a Sliding Mode Fractional Observer (SMFO). Both observers are used to perform disturbance reconstruction considered additive in a Quadrotor Unmanned Aerial Vehicle (UAV) model. Then, this work presents the fractional-order sliding mode observer’s mathematical formulation and integration into the Quadrotor UAV model. To validate the quality of the disturbance reconstruction process of the proposed SMFO observer scheme, numerical simulations are carried out, where a reconstruction quality indicator (BQR) is proposed based on the analysis of performance indices such as the Mean Square Error (MSE), the First Probability Moment (FPM), and Second Probability Moment (SPM), which were obtained for both the SMCO and the SMFO. The simulation results demonstrate the efficacy of the proposed observer in accurately reconstructing disturbances under various environmental conditions. Comparative analyses with SMCO highlight the advantages of the fractional-order approach in terms of reconstruction accuracy and improvement of its transitory performance. Finally, the presented SMFO offers a promising avenue for enhancing the reliability and precision of disturbance estimation, ultimately contributing to the advancement of robust control strategies for Quadrotor UAV systems.

Seven new peptides denominated CboK1 to CboK7 were isolated from the venom of the Mexican scorpion Centruroides bonito and their primary structures were determined. The molecular weights ranged between 3760.4 Da and 4357.9 Da, containing 32 to 39 amino acid residues with three putative disulfide bridges. The comparison of amino acid sequences with known potassium scorpion toxins (KTx) and phylogenetic analysis revealed that CboK1 (α-KTx 10.5) and CboK2 (α-KTx 10.6) belong to the α-KTx 10.x subfamily, whereas CboK3 (α-KTx 2.22), CboK4 (α-KTx 2.23), CboK6 (α-KTx 2.21), and CboK7 (α-KTx 2.24) bear > 95% amino acid similarity with members of the α-KTx 2.x subfamily, and CboK5 is identical to Ce3 toxin (α-KTx 2.10). Electrophysiological assays demonstrated that except CboK1, all six other peptides blocked the Kv1.2 channel with Kd values in the picomolar range (24–763 pM) and inhibited the Kv1.3 channel with comparatively less potency (Kd values between 20–171 nM). CboK3 and CboK4 inhibited less than 10% and CboK7 inhibited about 42% of Kv1.1 currents at 100 nM concentration. Among all, CboK7 showed out-standing affinity for Kv1.2 (Kd = 24 pM), as well as high selectivity over Kv1.3 (850-fold) and Kv1.1 (~6000-fold). These characteristics of CboK7 may provide a framework for developing tools to treat Kv1.2-related channelopathies.

Las innovaciones en los constantes cambios tecnológicos hacen que las competencias en tecnologías de la información y la comunicación, sean indispensables para poder desarrollarse en el campo profesional. Estudios evidencian que algunos estudiantes de posgrado no tienen competencias en el uso de estas tecnologías. El objetivo es estudiar las competencias sobre el uso de las tecnologías de información y comunicación en los estudiantes de postgrados de Educación a Distancia de México y Colombia, que estudian en la Universidad Cuauhtémoc, Plantel Aguascalientes. La metodología fue descriptivo-comparativa y diseño no experimental, transversal. Los participantes fueron 635 estudiantes inscritos en dichos postgrado. La encuesta exploratoria evaluó las competencias en el conocimiento de las tecnologías descritas y datos sociodemográficos como género, país de residencia, además del programa académico; realizando pruebas X2 y p, a fin de saber la significancia entre las variables de estudio que corresponde a los conocimientos por género y país de residencia. Los datos revelan asociación en los alumnos respecto al nivel de conocimientos y frecuencia de uso en capacidades. Se concluye que las competencias en tecnologías de información y comunicación de los estudiantes de postgrado al estar en una modalidad de enseñanza mediada por tecnología, son indispensables y deben desarrollarse.

Hypertension can be induced by the disruption of factors in blood pressure regulation. This includes several systems such as Neurohumoral, Renin-angiotensin-aldosterone, the Circadian clock, and melatonin production, which can induce elevation and non-dipping blood pressure. Melatonin has a supraphysiological role as a chronobiotic agent and modulates vascular system processes via pro/antiangiogenic factors, inflammation, the immune system, and oxidative stress regulation. An elevation of melatonin production is observed during pregnancy, modulating the placenta and fetus’s physiological functions. Their impairment production can induce temporal desynchronization of cell proliferation, differentiation, or invasion from trophoblast cells results in vascular insufficiencies, elevating the risk of poor fetal/placental development. Several genes are associated with vascular disease and hypertension during pregnancy via impaired inflammatory response, hypoxia, and oxidative stress, such as cytokines/chemokines IL-1β, IL-6, IL-8, and impairment expression in endothelial cells/VSMCs of HIF1α and eNOS genes. Pathological placentas showed differentially expressed genes (DEG), including vascular genes as CITED2, VEGF, PL-II, PIGF, sFLT-1, and sENG, oncogene JUNB, scaffolding protein CUL7, GPER1, and the pathways of SIRT/AMPK and MAPK/ERK. Additionally, we observed modification of subunits of NADPH oxidase and extracellular matrix elements, i.e., Glypican and Heparanase and KCa channel. Mothers with a low level of melatonin showed low production of proangiogenic factor VEGF, increasing the risk of preeclampsia, premature birth, and abortion. In contrast, melatonin supplementation can reduce systolic pressure, prevent oxidative stress, induce the activation of the antioxidants system, and lessen proteinuria and serum level of sFlt-1. Moreover, melatonin can repair the endothelial damage from preeclampsia at the placenta level, increasing PIGF, Nrf-2, HO-1 production and reducing critical markers of vascular injury during the pregnancy. Melatonin also restores the umbilical and uterine blood flow after oxidative stress and inhibits vascular inflammation and VCAM-1, Activin-A, and sEng production. The beneficial effects of melatonin over pathological pregnancies can be partially observed in normal pregnancies, suggesting the dual role of/over placental physiology could contribute to protection and have therapeutic applications in vascular pathologies of pregnancies in the future.

Nowadays, various systems were developed in the telecommunications field which make use of technologies for the transmission and reception of information. One of these technologies is the Internet, which was developed in tandem with scientific growth. Therefore, its application in the control of various industrial processes has a notable influence. In this context, there are industrial processes that, due to the potential danger they represent to human beings, must be controlled by means of a remote control system. Such systems can be implemented through client–server communication schemes, which form a network of computers to exchange information. In the exchange of information, delay times are generated. These inactivity times have a close relationship with the latency in the communication network and have a negative impact on the performance of closed-loop control systems. In this sense, for physical implementation, it is essential to measure and mathematically characterize their magnitudes in order to know their variability and thus be able to design control strategies that compensate for their effects. Hence, this research paper presents the reconstruction of the communication times measured from a telecontrol system, where it is assumed that only one subsystem acts as the controller and the other one acts as the controlled. In other words, this paper addresses a control scheme type of single-input-single-output system (SISO). This reconstruction is based on the Kalman filter, which estimates the communication times that are measured on an experimental test bench with a client–server communication scheme. Communication times are characterized as stochastic processes. So, in order to validate the reconstruction presented, the level of dependence between the random processes is evaluated by analyzing their moments of probability as well as their covariance moments. Finally, an analysis based on the mean square error is presented, through which it can be concluded that the reconstruction technique used allows one to know the dynamics of the communication times generated by the remote control process presented in this research.

The interaction of digital systems with dynamic systems requires synchrony and the accomplishment of time constrains, so the simulation of physical processes needs an implementation by means of real-time systems (RTS). However, as it can be expected, every simulation and/or implementation might demand too many computational resources, surpassing the capacity of the processor used by computational systems. This is the reason for the need to perform a temporary computational complexity analysis based on the study of the behavior of the execution times of the implemented simulation. In this regard, the Real-Time Operating Systems (RTOS) feature time managing tools, which allow their precise measurement and the establishment of scheduling criteria in process execution. Therefore, this research proposes accomplishing a temporary computational complexity analysis of the real-time simulation by an embedded system (ES) of an unmanned aerial vehicle (UAV) propelled by four rotors. Derived from this analysis, formal definitions are elaborated and proposed, which establish a close relationship between the temporary computational complexity and typical real-time temporary constraints. To the best of the author’s knowledge, the definitions presented in this article have not been reported in the literature. Furthermore, to perform the temporary computational complexity analysis of the UAV, the mathematical modeling based on the Euler–Lagrange approach is presented in detail. Finally, simulations were performed using a real-time system implemented on the Embedded Computer System (ECS) Raspberry Pi 2 Model B+, in order to validate the suggested definitions.

En el presente trabajo se ha aplicado la estadística robusta para la identificación de valores “outliers” en la determinación del factor recobrado en el análisis de residuos de clorpirifos en maní por cromatografía de gases con detector ECD. Para ello fue elaborado un programa en lenguaje HP-BASIC, basado en la estadística robusta y específicamente en el algoritmo de Huber y el cual fue editado en la calculadora gráfica de última generación HP PRIME Graphing Calculator. El programa fue ejecutado ingresando los datos obtenidos de los resultados de la evaluación del factor de recobrado para el método de análisis de clorpirifos en una muestra de referencia interna de maní, obteniéndose como resultado un estimado de los parámetros de la población y la identificación de 3 “outliers”. Este programa fue validado con uno de referencia elaborado en Excel por el Comité de Métodos Analíticos de la Royal Society of Chemistry, observándose que la desviación de los parámetros de la población (m,s) fueron menores que la precisión iterativa, lo que indica que no hubo diferencias significativas entre los dos programas. Por otro lado, estos resultados se compararon con los obtenidos por las pruebas clásicas de Dixon y de Grubbs, concluyendo que el método de Huber es el más sensible. El menos sensible es el test de Dixon, dado que su aplicación no detectó ningún outlier, mientras que el test de Grubbs identificó los dos valores más pequeños.

Enzymes are an integral part of animal venoms. Unlike snakes, in which enzymes play a primary role in envenomation, in scorpions, their function appears to be ancillary in most species. Due to this, studies on the diversity of scorpion venom components have focused primarily on the peptides responsible for envenomation (toxins) and a few others (e.g., antimicrobials), while enzymes have been overlooked. In this work, a comprehensive study on enzyme diversity in scorpion venoms was performed by transcriptomic and proteomic techniques. Enzymes of 63 different EC types were found, belonging to 330 orthogroups. Of them, 24 ECs conform the scorpion venom enzymatic core, since they were determined to be present in all the studied scorpion species. Transferases and lyases are reported for the first time. Novel enzymes, which can play different roles in the venom, including direct toxicity, as venom spreading factors, activators of venom components, venom preservatives, or in prey pre-digestion, were described and annotated. The expression profile for transcripts coding for venom enzymes was analyzed, and shown to be similar among the studied species, while being significantly different from their expression pattern outside the telson.

RESUMEN Introducción: las enfermedades agudas del aparato respiratorio se presentan en su inmensa mayoría como infecciones, por lo cual en la actualidad se prefiere referirse a ellas como infecciones respiratorias agudas. Objetivos: determinar el comportamiento de algunos factores de riesgo de infecciones respiratorias agudas en niños menores de 5 años, de mayo 2014 a mayo 2015 en los consultorios médicos del policlínico Luis E. de la Paz, municipio de Yara, Granma, Cuba. Método: se realizó una investigación epidemiológica, de tipo descriptiva y transversal, con una fase analítica. La población fue de 696 niños, que presentaron infecciones respiratorias agudas y asistieron a consulta. La información se obtuvo a través de una planilla de recogida de datos, cuestionario a las madres de los niños y entrevista a informantes clave y se procesó mediante el estadístico Chi cuadrado, para determinar el grado de dependencia y su correlación a través del estadígrafo coeficiente de correlación de Pearson. Resultados: el grupo etáreo más afectado, que fue el de 1-2 años, del sexo femenino. Los factores de riesgo más frecuentes fueron el hacinamiento, el hábito de fumar en familiares, la lactancia materna inadecuada y el nivel socioeconómico no aceptable. Conclusiones: se evidenció la alta correlación de la edad de los pacientes estudiados con el nivel socio-económico, seguido del antecedente de bajo peso al nacer, luego el hábito de fumar y la utilización de la lactancia materna. Fue mayoritario el nivel de conocimiento de las madres sobre factores de riesgo de estas enfermedades. ABSTRACT Introduction: acute diseases of the respiratory system appear in their vast majority as infections, which is why they are now preferred to be referred to as acute respiratory infections. Objectives: to determine the behavior of some risk factors for acute respiratory infections in children under 5 years of age, from May 2014 to May 2015 in the medical offices of the Luis E. de la Paz polyclinic, Yara municipality, Granma, Cuba. Method: an epidemiological investigation, of descriptive and transversal type, was carried out with an analytical phase. The population was 696 children, who had acute respiratory infections and attended the consultation. The information was obtained through a data collection form, questionnaire to the mothers of the children and interviewed key informants and was processed using the Chi square statistic, to determine the degree of dependence and its correlation through the statistic coefficient of Pearson correlation. Results: the most affected age group was female children from 1-2 years. The most frequent risk factors were overcrowding, family smoking, inadequate breastfeeding, and unacceptable socioeconomic status. Conclusions: the high correlation of the age of the studied patients with the socioeconomic level was evidenced, followed by the antecedent of low birth weight, then the smoking habit and the use of breastfeeding. The mothers' level of knowledge about the risk factors of these diseases was higher.

A model and real-time simulation of a gas turbine engine (GTE) by real-time tasks (RTT) is presented. A Kalman filter is applied to perform the state vector identification of the GTE model. The obtained algorithms are recursive and multivariable; for this reason, ANSI C libraries have been developed for (a) use of matrices and vectors, (b) dynamic memory management, (c) simulation of state-space systems, (d) approximation of systems using equations in matrix finite difference, (e) computing the mean square errors vector, and (f) state vector identification of dynamic systems through digital Kalman filter. Simulations were performed in a Single Board Computer (SBC) Raspberry Pi 2® with a real-time operating system. Execution times have been measured to justify the real-time simulation. To validate the results, multiple time plots are analyzed to verify the quality and convergence time of the mean square error obtained.

The information technologies have evolved in such a way that communication between computers or hosts has become common, so much that the worldwide organization (governments and corporations) depends on it; what could happen if these computers stop working for a long time is catastrophic. Unfortunately, networks are attacked by malware such as viruses and worms that could collapse the system. This has served as motivation for the formal study of computer worms and epidemics to develop strategies for prevention and protection; this is why in this paper, before analyzing epidemiological models, a set of formal definitions based on set theory and functions is proposed for describing 21 concepts used in the study of worms. These definitions provide a basis for future qualitative research on the behavior of computer worms, and quantitative for the study of their epidemiological models.

Comentario al artículo “Daniel Carrión García: estudio iconográfico y antropológico forense”

En el presente artículo pretendo contextualizar de manera sucinta la figura de Antonio de Cabezón en el Nuevo Mundo, a partir de las copias de sus Obras de Música que circularon en México desde el año de 1586, a tan solo ocho años de haber sido publicadas en Madrid por su hijo Hernando el año de 1578. Asimismo, argumento la existencia de una tipología de órgano en México, heredera del principio del Blockwerk, vinculada con el órgano castellano de la época cabezoniana, representada, en este caso, por un grupo de órganos históricos de la provincia de Oaxaca en el sureste de México.

In the biological environment, there has been created epidemiological models that attempt to explain the spread dynamics of an epidemic in a population to predict the behavior of possible epidemics that can affect humanity. Based on that, this paper focused on the study of epidem­ics worms because they can spread by themselves from one infected host to the entire network of susceptible hosts. In this paper we analyzed the susceptible-infected (SI) model which assumes that in a community with n individuals, the num­ber of individuals in the susceptible state S(t) are in direct contact with the number of individuals that are in infected state I(t). These last individuals can spread the infection or switch to an infectious state with the factor B as a speed of infection. This model is based on differential equations so it can­not be implemented directly on a computer. Due to the complexity of this model, it is proposed an approximate model based on finite different equa­tions to achieve a simulation of the epidemic us­ing a set theory and cardinality obtaining an itera­tive numerical method which consists on basics arithmetic operations. Additionally, having in mind this is an approximate model, it will be pre­sented an error due to truncation or rounding. At the end of this paper it will be presented a case of study developed in Simulink of Matlab software, and the results of the model based on difference equations is compared with the finite-difference approximate model including the analysis of ap­proximation errors

Many peptides in scorpion venoms are amidated at their C-termini. This post-translational modification is paramount for the correct biological function of ion channel toxins and antimicrobial peptides, among others. The discovery of canonical amidation sequences in transcriptome-derived scorpion proproteins suggests that a conserved enzymatic α-amidation system must be responsible for this modification of scorpion peptides. A transcriptomic approach was employed to identify sequences putatively encoding enzymes of the α-amidation pathway. A dual enzymatic α-amidation system was found, consisting of the membrane-anchored, bifunctional, peptidylglycine α-amidating monooxygenase (PAM) and its paralogs, soluble monofunctional peptidylglycine α-hydroxylating monooxygenase (PHMm) and peptidyl-α-hydroxyglycine α-amidating lyase (PALm). Independent genes encode these three enzymes. Amino acid residues responsible for ion coordination and enzymatic activity are conserved in these sequences, suggesting that the enzymes are functional. Potential endoproteolytic recognition sites for proprotein convertases in the PAM sequence indicate that PAM-derived soluble isoforms may also be expressed. Sequences potentially encoding proprotein convertases (PC1 and PC2), carboxypeptidase E (CPE), and other enzymes of the α-amidation pathway, were also found, confirming the presence of this pathway in scorpions.

Los sistemas en tiempo real (STR) procesan sus actividades a través de tareas que a su vez están formadas por un conjunto de instancias, las cuales tienen seis restricciones temporales: tiempo de arribo, tiempo de inicio, tiempo de ejecución, tiempo de finalizado, tiempo excedente y plazo. De estas seis restricciones, el tiempo de ejecución depende directamente del software y hardware de la computadora, originando que la variación de esta restricción temporal esté vinculada con diversos factores externos e internos, esta variación puede ocasionar que algunas instancias no cumplan su plazo; por este motivo es importante proponer un modelo para reconstruir el comportamiento de los tiempos de ejecución, con el fin de: dimensionar de manera correcta el sistema en tiempo real, proponer técnicas adecuadas de tolerancia a fallos y mejorar sus módulos de operación. Por lo cual en este trabajo, se propone un modelo para reconstruir los tiempos de ejecución obtenidos de la medición hecha a un algoritmo de programación elaborado en el sistema operativo en tiempo real QNX Neutrino 6.5. Dicha reconstrucción se hace a través de un modelo tipo autoregresivo de promedios móviles integrado con un estimador de parámetros construido con un procedimiento de filtrado digital difuso (FDD). Se usa el error cuadrático medio para validar la reconstrucción, el cual converge a una región cercana a cero y permite concluir que la reconstrucción es buena.

Un Sistema en Tiempo Real (STR) implantado en una computadora digital, interactúa con el mundo físico a través del acondicionamiento de variables (sensores, actuadores convertidores Analógico/Digital A/D y Digital/ Analógico D/A) y procesa sus peticiones mediante tareas en tiempo real (Ji: i¿Z+). Cada Ji está formada por un conjunto de instancias {ji,k: i, k¿Z+, i es el índice de la tarea, k es el índice de la instancia} con al menos tres restricciones temporales: tiempo de arribo, tiempo de ejecución y plazo (Li,k, Ci,k, Di,k). En este sentido, es importante proponer un modelo para reconstruir el comportamiento de los tiempos de ejecución Ci,k. El modelo propuesto es un ARMA con un estimador de parámetros basado en la variable instrumental. Los tiempos de ejecución fueron medidos experimentalmente en QNX Neutrino 6.5 utilizando un procesador Intel Core i7 de 2.66 GHz. Se presentan los antecedentes teóricos del modelado de tareas en tiempo real, las mediciones de tiempo de ejecución, el modelo de tiempos de ejecución, el estimador de parámetros con variable instrumental, la experimentación y los resultados.

El Libro de Torres de la colección Sánchez Garza, es uno de los documentos más polémicos de los últimos tiempos en la musicología hispánica. Esta polémica ha sido el resultado de dos factores fundamentales: por un lado el problema de la autoría, y por el otro, el aparente desorden del contenido musical del manuscrito, debido supuestamente, al trabajo inefi ciente de los copistas que le dieron forma. Esto último ha llevado a concluir, como opinión generalizada, que se trata de una copia corrompida de las obras para órgano que habrían sido compuestas por el prestigiado compositor, organista, teórico musical e impresor español, Joseph de Torres y Martínez Bravo (*1670c; †1738), en cuyo caso el copista del manuscrito sería el responsable de dicho desorden; lo que ha llevado a suponer, a otros investigadores, que incluso las obras en cuestión no sean de su autoría. A esto debemos agregar la confusa y a veces errónea transcripción ofrecida por el CENIDIM en 1993, en cuyo caso las obras han sido adjudicadas a José de Torres y Vergara, un personaje mexicano, homónimo y contemporáneo de Torres y Martínez Bravo.

El presente artículo es una descripción sumaria de los órganos históricos de la catedral de México. Inicio con una síntesis histórica de los instrumentos, posteriormente hago un análisis de su composición fónica, y concluyo con una breve reseña de su estado actual. Sin lugar a dudas, estos instrumentos son los más importantes en su tipo en el continente americano. Como es bien sabido, estos fueron restaurados hace treinta años por la compañía Flentrop Orgelbouw de Zaandam, Holanda. Actualmente, a tres décadas, se proyecta una nueva restauración. Hacemos votos para que este proyecto se consolide en beneficio de la recuperación patrimonial de tan importantes instrumentos.

Real-time systems (RTS) process their activities through tasks which in turn consist of a set of instances, each one of this real-time task (RTT) have six temporary constraints: arrival time, start time, execution time, end time, over time and deadline. Of these six constraints, the execution time depends directly on the software and hardware of the computer, because of that this temporary constraints varies due to external and internal factors, this variation may cause at least some instance does not satisfy the deadline, in this sense it is important to propose a model to reconstruct the behavior of the execution times for the purpose to determine the proportions of the Real-time System, propose appropriate techniques of fault tolerance and improve operating modules. Therefore in this paper, is proposed a model to reconstruct the execution times from measurements made at a program algorithm developed in the real-time operating system QNX Neutrino 6.5. This reconstruction is done by a model type autoregressive–moving-average integrated with parameter estimator constructed with a digital filtering procedure diffuse (FDD). To validate the reconstruction is used the mean square error which converges to a region close to zero and indicate that the reconstruction is good.

A Real-time System (RTS) implemented in a digital computer interacts with the physical world through knowledge variables (sensors, actuators, Analogical - Digital, and Digital-Analogical convertors) processing its requirements through real-time tasks (Ji: i∈Z+). Each Ji is formed by a set of instances {ji,k: i, k∈Z+, i is the task index, k is the instance index} with at least three time constraints: arrival, execution and, interval times (Li,k, Ci,k, Di,k). The execution time identification ˆCi ,k , is based on Instrumental Variable parameter estimation and the recursive state space ARMA model. The execution times were measured experimentally using a Real-time Operative System QNX 6.5 Neutrino in an Intel Core i7 processor with a speed of 2.66 GHz. This paper presents a state of the art real-time task model, execution time measurements, an Instrumental Variable parameter estimator on recursive state space identification, experimentation and, results.