Sobrevivencia del embrión humano durante el periodo de organogénesis

En este artículo se aborda el tema de establecer cómo el embrión humano crece y sobrevive durante el periodo de organogénesis que se extiende entre la semana 4 y 8 del desarrollo. En esta fase del desarrollo el embrión está generando sus futuros órganos y tejidos a pesar de no tener aún órganos funcionales ni hematopoyéticos. Basados en nuestras propias investigaciones y en los pocos datos existentes en la literatura referentes a la sobrevivencia del embrión humano podemos afirmar que los suministros necesarios para la sobrevida del embrión en este periodo provienen del saco vitelino, un anexo embrionario de fundamental importancia en el crecimiento embrionario. Se analiza el potencial del saco vitelino en la generación de la primera sangre (eritroblastos primitivos), en la generación de los eritrocitos no nucleados (ENN) y proteínas séricas. Se discute el rol de los ENN en el transporte de oxígeno, en la producción del Hierro necesario para la síntesis de hemoglobina y en la función hematopoyética embrionaria. Palabra sclaves: Embrión humano; Nutrición embrionaria; Saco vitelino; Eritropoyesis embrionaria; Eritrocitos no nucleados

El Feto, un Paciente que Espera

La preocupación sobre la salud fetal surge en nuestra sociedad a medida que se conoce que una de las causas fundamentales de las muertes prenatales es debida a las malformaciones y enfermedades fetales. En este artículo, se entrega información relevante sobre este tema que es de alta complejidad. Las preguntas que surgen frente a estos hechos son:¿Cómo y cuando enferma un feto?, ¿Cómo se pueden prevenir estas enfermedades o bien curarlas?, ¿Que se puede hacer frente a un feto enfermo? El objetivo de nuestro artículo es aportar información sobre un tema no bien conocido pero que, de una u otra forma, interesa a cada uno de nosotros

Las audiencias virtuales y sus implicancias en los delitos de omisión alimentaria en el Distrito Judicial del Callao, 2021

En el presente trabajo de investigación titulada “Las Audiencias Virtuales y sus Implicancias en los Delitos de Omisión Alimentaria en el Distrito Judicial del Callao, 2021”. Teniendo como objetivo principal, Analizar si se garantiza el acceso a la justicia, a través de las audiencias virtuales en los delitos por omisión alimentaria en el distrito judicial del Callao, 2021. En el presente trabajo de investigación se realizó teniendo en cuenta el enfoque cualitativo de tipo de investigación básica y con un diseño interpretativo basado en la teoría fundamentada que buscó analizar y fundamentar las categorías consignadas en la investigación además se hizo uso del instrumento de la guía de entrevista, que contiene nueve preguntas, siendo validados por expertos y dirigidos a una categorización de sujetos. Se concluye que el acceso a la justicia a través de las audiencias virtuales no se ve vulnerado en los delitos de omisión alimentaria en el distrito judicial del Callao, 2021

Cambios relacionados con la edad en las Funciones Ejecutivas de niños colombianos

Executive Function (EF) is a higher cognitive process responsible for control and self-regulation of behavior. The aim of this study is to describe the developmental trajectory of EF in four and six-year old Colombian children, and to highlight possible differences by socio-cultural variables such as age, sex, type of school or socio-economic status. One hundred and sixty-three normotypical children were tested using psychological tests validated for a Spanish population belonging to the Weschler and Luria Initial batteries. HJ-biplot analysis showed that EF developed commensurate with age and school grade, although differences by socioeconomic status and type of school were evidentLas funciones ejecutivas (FE) son un proceso cognitivo superior para la autorregulación y control del comportamiento. El objetivo del estudio fue describir las trayectorias de desarrollo de 163 niños colombianos normotípicos de 4 y 6 años de edad y resaltar las diferencias observadas según variables sociodemográficas como edad, sexo, tipo de colegio y condición socioeconómica. Para ello, se aplicaron pruebas psicológicas validadas para población hispanohablante y que conforman las baterías de la Weschler y Luria inicial. Los análisis HJ-biplot realizados muestran que las FE se desarrollan en relación con la edad y el grado escolar de los niños, no obstante, también se observaron diferencias asociadas a las condiciones socioeconómicas y tipo de colegio al que asisten los niños

“Los gastos de responsabilidad social y la determinación del impuesto a la renta de las empresas madereras de la Amazonía del Perú. periodo 2013- 2017.”

La tesis titulada “Los gastos de responsabilidad social y la determinación del Impuesto a la Renta de las empresas madereras de la Amazonía del Perú, periodo 2013 - 2017” determinó que las empresas madereras ubicadas en la zona de la Amazonía, por su actividad extractiva y de transformación recurrieron a la generación de gastos de carácter social no porque hubiera existido una voluntad de generarlos sino de la necesidad de efectuarlos dada la geografía en la que se ubica la concesión forestal cedida por el Estado Peruano para su explotación es por ello que necesariamente se produjeron la generación de Gastos de Responsabilidad Social en la determinación del Impuesto a la Renta de las Empresas Madereras ubicadas en la zona de la Amazonía del Perú en los años 2013 a 2017. El tipo de investigación es cuantitativa de característica aplicada, con un nivel descriptivo, el diseño fue experimental y el método descriptivo. A quedado demostrado estadísticamente que la deducción de los Gastos de Responsabilidad Social a favor del contribuyente se relaciona inversamente con la determinación del impuesto a la renta de las empresas madereras de la Amazonía del Perú. Periodo 2013- 2017.Tesi

Development of EEG-based technologies for the characterization and treatment of neurological diseases affecting the motor function

This thesis presents a set of studies applying signal processing and data mining techniques in real-time working systems to register, characterize and condition the movement-related cortical activity of healthy subjects and of patients with neurological disorders affecting the motor function. Patients with two of the most widespread neurological affections impairing the motor function are considered here: patients with essential tremor and patients who have suffered a cerebro-vascular accident. The different chapters in the presented thesis show results regarding the normal cortical activity associated with the planning and execution of motor actions with the upper-limb, and the pathological activity related to the patients' motor dysfunction (measurable with muscle electrodes or movement sensors). The initial chapters of the book present i) a revision of the basic concepts regarding the role of the cerebral cortex in the motor control and the way in which the electroencephalographic activity allows its analysis and conditioning, ii) a study on the cortico-muscular interaction at the tremor frequency in patients with essential tremor under the effects of a drug reducing their tremor, and finally iii) a study based on evolutionary algorithms that aims to identify cortical patterns related to the planning of a number of motor tasks performed with a single arm. In the second half of the thesis book, two brain-computer interface systems to be used in rehabilitation scenarios with essential tremor patients and with patients with a stroke are proposed. In the first system, the electroencephalographic activity is used to anticipate voluntary movement actions, and this information is integrated in a multimodal platform estimating and suppressing the pathological tremors. In the second case, a conditioning paradigm for stroke patients based on the identification of the motor intention with temporal precision is presented and tested with a cohort of four patients along a month during which the patients undergo eight intervention sessions. The presented thesis has yielded advances from both the technological and the scientific points of view in all studies proposed. The main contributions from the technological point of view are: ¿ The design of an integrated upper-limb platform working in real-time. The platform was designed to acquire information from different types of noninvasive sensors (EEG, EMG and gyroscopic sensors) characterizing the planning and execution of voluntary movements. The platform was also capable of processing online the acquired data and generating an electrical feedback. ¿ The development of signal processing and classifying techniques adapted to the kind of signal recorded in the two kinds of patients considered in this thesis (patients with essential tremor and patients with a stroke) and to the requirements of online processing and real-time single-trial function desired for BCI applications. Especially in this regard, an original methodology to detect onsets of voluntary movements using slow cortical potentials and cortical rhythms has been presented. ¿ The design and validation in real-time of asynchronous BCI systems using motor planning EEG segments to anticipate or detect when patients begin a voluntary movement with the upper-limb. ¿ The proof of concept of the advantages of an EEG system integrated in a multimodal human-robot interface architecture that constitutes the first multimodal interface using the combined acquisition of EEG, EMG and gyroscopic data, which allows the concurrent characterization of different parts of the body associated with the execution of a movement. The main scientific contributions of this thesis are: ¿ The study of the EEG-based anticipation of voluntary movements presented in Chapter 5 of the thesis was the first demonstration (to the author's knowledge) of the capacity of the EEG signal to provide reliable movement predictions based on single-trial classification of online data of healthy subjects and ET patients. This study also provides, for the first time, the results of a BCI system tested in ET patients and it represents an original approach to BCI applications for this group of patients. ¿ It has been presented the first neurophysiological study using EEG and EMG data to analyze the effects of a drug on cortical activity and tremors of patients with ET. In addition, the obtained results have shown for the first time that a significant correlation exists between the dynamics of specific cortical oscillations and pathological tremor manifestation as a consequence of the drug effects. ¿ It has been proposed for the first time an experiment to inspect whether the EEG signal carries enough information to classify up to seven different tasks performed with a single limb. Both the methodology applied and the validation procedure are also innovative in this sort of studies. ¿ It has been demonstrated for the first time the relevance of combining different cortical sources of information (such as BP and ERD) to estimate the initiation of voluntary movements with the upper-limb. In this line, special relevance may be given to the positive results achieved with stroke patients, improving the results presented by similar previous EEG-based studies by other research groups. It has also been proposed for the first time an upper-limb intervention protocol for stroke patients using BP and ERD patterns to provide proprioceptive feedback tightly associated with the patients' expectations of movement. The effects of the proposed intervention have been studied with a small group of patients

Event-related desynchronization-based versus bereitchaftspotential-based classfiers in stroke patiens

To compare the most well-known volitional movement-related electrophysiological phenomena for upper-limb movements in stroke patients, as source of movement classifiers.Peer Reviewe

Influence of common synaptic input to motor neurons on the neural drive to muscle in essential tremor

Tremor in essential tremor (ET) is generated by pathological oscillations at 4 to 12 Hz, likely originating at cerebello-thalamo-cortical pathways. However, the way in which tremor is represented in the output of the spinal cord circuitries is largely unknown because of the difficulties in identifying the behavior of individual motor units from tremulous muscles. By using novel methods for the decomposition of multichannel surface EMG, we provide a systematic analysis of the discharge properties of motor units in 9 ET patients, with concurrent recordings of EEG activity. This analysis allowed inferring the contribution of common synaptic inputs to motor neurons in ET. Motor unit short-term synchronization was significantly greater in ET patients than in healthy subjects. Further, the strong association between the degree of synchronization and the peak in coherence between motor unit spike trains at the tremor frequency indicated that the high synchronization levels were generated mainly by common synaptic inputs specifically at the tremor frequency. The coherence between EEG and motor unit spike trains demonstrated the presence of common cortical input to the motor neurons at the tremor frequency. Nonetheless, the strength of this input was uncorrelated to the net common synaptic input at the tremor frequency, suggesting a contribution of spinal afferents or secondary supraspinal pathways in projecting common input at the tremor frequency. These results provide the first systematic analysis of the neural drive to the muscle in ET and elucidate some of its characteristics that determine the pathological tremulous muscle activity.This work was funded by the EU Commission [grant number EU-FP7-2011-287739 (NeuroTREMOR)].Peer reviewe

2018 Atmospheric Motion Vector (AMV): intercomparison study

Atmospheric Motion Vectors (AMVs) calculated by six different institutions (Brazil Center for Weather Prediction and Climate Studies/CPTEC/INPE, European Organization for the Exploitation of Meteorological Satellites/EUMETSAT, Japan Meteorological Agency/JMA, Korea Meteorological Administration/KMA, Unites States National Oceanic and Atmospheric Administration/NOAA, and the Satellite Application Facility on Support to Nowcasting and Very short range forecasting/NWCSAF) with JMA’s Himawari-8 satellite data and other common input data are here compared. The comparison is based on two different AMV input datasets, calculated with two different image triplets for 21 July 2016, and the use of a prescribed and a specific configuration. The main results of the study are summarized as follows: (1) the differences in the AMV datasets depend very much on the ‘AMV height assignment’ used and much less on the use of a prescribed or specific configuration; (2) the use of the ‘Common Quality Indicator (CQI)’ has a quantified skill in filtering collocated AMVs for an improved statistical agreement between centers; (3) Among the six AMV operational algorithms verified by this AMV Intercomparison, JMA AMV algorithm has the best overall performance considering all validation metrics, mainly due to its new height assignment method: ‘Optimal estimation method considering the observed infrared radiances, the vertical profile of the Numerical Weather Prediction wind, and the estimated brightness temperature using a radiative transfer model’.The “Space Science and Engineering Center” (SSEC) of the “University ofWisconsin-Madison” (UW) was funded to do this research by the “European Organization for the Exploitation of Meteorological Satellites (EUMETSAT)”, through the “Satellite Application Facility on Support to Nowcasting and Very short range forecasting (NWCSAF)” “Visiting Scientist Activity (VSA)” program