University of the Andes (Venezuela)

Synergistic studies of microorganisms in the last decade have been mostly directed towards their biofertilizing effects on growth and crop yield. Our research examines the role of a microbial consortium (MC) on physiological responses of Allium cepa hybrid F1 2000 under water and nutritional deficit in a semi-arid environment. An onion crop was established with normal irrigation (NIr) (100% ETc) and water deficit (WD) (67% ETc) and different fertilization treatments (MC with 0%, 50% and 100% NPK). Gas exchange (Stomatal conductance (Gs), transpiration (E) and CO 2 assimilation rates (A)) and leaf water status were evaluated throughout its growth cycle. The MC + 50% NPK treatment with NIr maintained similar A rates to the production control. A. cepa decreased Gs by approximately 50% in the WD treatment. The highest water use efficiency (WUE) and an increase in the modulus of elasticity in response to water stress were obtained for the 100% NPK treatment under non-inoculated WD. The onion hybrid F1 2000 was tolerant to water stress and under non-limiting nutrient conditions, irrigation may be reduced. The MC facilitated the availability of nutrients under NIr allowing a 50% reduction in the application of high doses of fertilization without affecting yield, resulting in a suitable agroecological strategy for this crop. Keywords CO2 assimilation · Leaf conductance · Onion · Nutrient stress · PGPR · Water stress

The study aimedto evaluate the cognitive functioning of children and adolescents with type 1 diabetes mellitus (T1DM) recruited from the IAHULA Endocrinology Outpatient Unit and to compare it to that of non-diabetics as to investigate the influence on cognition of factors re-lated to the disease. An analytical, cross-sectional observational study was carried out on a group of 30 patients with T1DM between 8 and 16 years of age and on a control group of 30 individuals matched by age, gender, education, and socioeconomic status. Interrogation and review of medi-cal records to obtain data on the clinical characteristics and treatment of T1DM were conducted. The WISC IV test was then applied to evaluate cognition and intellectual coefficient (IQ). The average age of the diabetic patients was 13.27±2.31 years, and half of them were male. Lower scores were found in the different domains of the WISC IV in the group with T1DM (p<0.01). The IQ was found to be lower in children with T1DM than in con-trols (75.47±13.87 vs. 88.57±11.06; p=0.0001). Likewise, a higher fre-quency of IQ scores below the 10th percentile was observed in the diabetic children (63.3% vs. 33.3%; p=0.02; Odds ratio: 3.45; 95%CI: 1.19-9.99). It was concluded that T1DM negatively impacts the cognitive performance of children and adolescents. Cognitive evaluation of these patients is recom-mended, as it could affect their daily life.

Fundamental studies have improved understanding of molecular-level properties and behavior in surfactant-oil-water (SOW) systems at equilibrium and under nonequilibrium conditions. However, confusion persists regarding the terms “microemulsion” and “curvature” in these systems. Microemulsion refers to a single-phase system that does not contain distinct oil or water droplets but at least four different structures with globular domains of nanometer size and sometimes arbitrary shape. The significance of “curvature” in such systems is unclear. At high surfactant concentrations (typically 30 wt % or more), a single phase zone has been identified in which complex molecular arrangements may result in light scattering. As surfactant concentration decreases, the single phase is referred to as a bicontinuous microemulsion, known as the middle phase in a Winsor III triphasic system. Its structure has been described as involving simple or multiple surfactant films surrounding more or less elongated excess oil and water phase globules. In cases where the system separates into two or three phases, known as Winsor I or II systems, one of the phases, containing most of the surfactant, is also confusedly referred to as the microemulsion. In this surfactant-rich phase, the only curved objects are micellar size structures that are soluble in the system and have no real interface but rather exchange surfactant molecules with the external liquid phase at an ultrafast pace. The use of the term “curvature” in the context of these complex microemulsion systems is confusing, particularly when applied to merged nanometer-size globular or percolating domains. In this work, we discuss the terms “microemulsion” and “curvature”, and the most simple four-dimensional spatiotemporal model is proposed concerning SOW equilibrated systems near the optimum formulation. This model explains the motion of surfactant molecules due to Brownian movement, which is a quick and arbitrary thermal fluctuation, and limited to a short distance. The resulting observation and behavior will be an average in time and in space, leading to a permanent change in the local microcurvature of the aggregate, thus changing the average from micelle-like to inverse micelle-like order over an extremely short time. The term “microcurvature” is used to explain the small variations of globule size and indicates a close-to-zero mean curvature of the surfactant-containing film surface shape.

This paper synthesizes a new sliding mode controller (SMC) approach to enhance tracking and regulation tasks by following dual-mode concepts. The new control law consists of two distinct types of operation, using the combination of higher gain to large error signals (transient) and lower gain to small error signals (the region around the set point). The design is presented from a dual-mode (PD−PID) sliding surface operating in concert, fulfilling desired control objectives to ensure stability and performance. Therefore, a new controller was established, and we called it a dual-mode based SMC. The proposed controller is tested by computer simulations applied to two nonlinear processes, a continuous stirred-tank reactor (CSTR) and a mixing tank with a variable dead time. The results are compared with two different alternatives of SMC. In addition, the merits and drawbacks of the control schemes are analyzed using radial graphs, comparing the control methods with various performance measures for set points and disturbances changes. The ITSE (integral of time multiplied by the squared error), TVu (total variation of control effort) indices, Mp (maximum overshoot), and ts (settling time) were the indices used for performance analysis and comparisons.

The Pacific Alliance deviates from other Latin American integration agreements due to its close association between governments and the private sector. Analysts have assessed the agreement as a pragmatic experience of regional integration to facilitate the free movement of production factors, a “tail moves dog” project, or an example of deep integration to diffuse liberal normative principles. This article analyzes the Pacific Alliance Business Council discourse to identify how the private sector perceives its role in the agreement and expresses it in the group's external negotiations, for example, Pacific Alliance–Mercosur, before contrasting its self‐defined role with those assumed by interpretations in the literature. We argue that the private sector sees its role as multifaceted, and this self‐perception escapes the limits of normative deep integration notions, allowing business to adapt to changes in internal and external factors. Business self‐perception contributes to enhance Pacific Alliance pragmatism and the application of an inductive micro‐negotiation methodology, but transversality may also influence the Business Council to support normative issues. La Alianza del Pacifico se diferencia de otros acuerdos de integración regional latinoamericana porque desde el principio otorgó un rol importante al sector privado. Esto ha llevado a que prevalezcan en la literatura tres interpretaciones del acuerdo—una experiencia pragmática de integración para facilitar el libre movimiento de los factores de producción, un proyecto dominado por el sector privado, o un intento por difundir principios normativos de liberalismo económico. Este artículo analiza el discurso del Consejo Empresarial de la Alianza del Pacífico para identificar cómo percibe su rol y lo expresa en su participación en las relaciones externas del grupo (por ejemplo, con Mercosur), antes de contrastarlo con interpretaciones en la literatura. Encontramos que ese rol es multifacético, evade los límites de la interpretación del acuerdo regional como un intento de difundir normativas neoliberales y permite a los empresarios adaptarse a cambios en factores internos y externos. De esta forma, refuerza el pragmatismo y conduce a aplicar una metodología inductiva de micro negociación, pero la transversalidad del Consejo puede influir para que los empresarios apoyen cuestiones normativas. 由于政府和私营部门之间的密切联系，太平洋联盟不同于其他拉美一体化协议。分析人士将该协议评估为一次用于促进生产要素自由流动的区域一体化务实经验、一项“局部牵动全身”项目、或一个用于传播自由规范原则的深度一体化范例。本文分析了太平洋联盟商业委员会话语，以确定私营部门如何看待其在协议中的作用，并在集团的外部谈判（例如太平洋联盟 ‐ 南方共同市场）中表达这一作用。本文随后将这一自定义角色与文献中所假设的作用进行对比。我们论证认为，私营部门认为其作用是多方面的，这种自我感知摆脱了规范性深度一体化概念的限制，使企业能够适应内外部因素的变化。商业自我感知有助于加强太平洋联盟的实用主义和归纳微观协商方法的应用，但横向性(transversality)也可能影响商业委员会，使其支持规范性问题。

Analyzing energy consumption is currently of great interest to define efficient energy management strategies. In particular, studying the evolution of the behavior of the consumption pattern can allow energy policies to be defined according to the time of the year. In this sense, this work proposes to study the evolution of energy behavior patterns using online clustering techniques. In particular, the centroids of the groups constructed by the techniques will represent their consumption patterns. Specifically, two unsupervised online machine learning techniques ideal for the stated objective will be analyzed, X-Means and LAMDA, since they are capable of varying and adapting the number of clusters at runtime. These techniques are applied to energy consumption data in commercial buildings, making groupings on previous groups, in our case, monthly and quarterly. We compared their performance by analyzing the evolution of the patterns over time. The results are very promising since the quality of the consumption patterns obtained is very good according to the performance metrics. Thus, the three main contributions of this article are to propose an approach to determine energy consumption patterns using online non-supervised learning approaches, a methodology to analyze and explain the evolution of energy consumption using centroids of clusters, and a comparison strategy of online learning techniques. The online clustering techniques have qualities of the order of 0.59 and 0.41 for Silhouette and Davies-Boulding, respectively, for X-Means and of the order of 0.71 and 0.24 for Silhouette and Davies-Boulding, respectively, for LAMDA in different datasets of energy. The results are motivating since very good results are obtained in terms of the quality of the clusters, particularly with LAMDA; therefore, analyzing its centroids as the patterns of user behaviors makes a lot of sense.

This paper presents the utilization of the Data Analysis Smart System (DASS) of ARMNANO in a nanotechnology application in electronic health. We made a special approach to the liver situation for patients that have been monitored with respect to two variables concerning their liver status: the Mean Corpuscular Volume (MCV) and the Alkaline phosphotas (ALKPHOS). These variables are analyzed using the autonomous cycle “Conditioning Thinking Mode” (CTM), one of the two autonomic cycles of data analysis tasks that make up the DASS. In this sense, an optimization problem is defined to determine the optimal deployment of nanosensors (NSs) for the proper determination of liver status. The application of genetic algorithms (GA) allows us to find the optimal number of NSs in the system to precisely determine the liver status, avoiding a large data volume. In total, we evaluated its implementation in two case studies and carried out a hyperparameterization process for assuring the definition of the key parameters. The greatest propensity is to place NSs in the regions close to the liver, becoming saturated as the amount of SNs increases (they do not improve the quality of the liver status value).

We are presenting new evidence on essential fatty acids (EFA) in prenatal human development. We have demonstrated, for the first time, the detailed process of active selection of some fatty acids by the placenta (biomagnification) and rejection of others (bioreduction) and how this strategy is of supreme importance for understanding of the biology of human reproduction. The biomagnification process by the placenta is dominated by arachidonic acid (ArA) and its allies: di-homo-gamma-linolenic acid (DGLA), adrenic acid and ω6 docosapentaenoic acid. Stearic acid is similarly bio-magnified which is likely to provide for the sn-1 position in membrane synthesis. In contrast there is a bioreduction of oleic, linoleic and all ω3 precursors for docosahexaenoic acid (DHA), including eicosapentaenoic acid (EPA). Although DHA is biomagnified, the amplification from mother to fetus is small compared to ArA. We report on the dominant compartmentalisation of ArA from mother to fetal plasma, cell membranes of red cells, mono-nuclear cells, endothelium and the placenta. We conclude that ArA and its allies, play a paramount role in the development of the products of conception. It is plausible that inadequate provision of ArA may be relevant to the neuro-vascular complications of prematurity and neurodevelopmental disorders associated with premature birth. We present evidence of ArA's universal role from an identical arachidonic acid-based strategy observed in contrasting cultures. The dominance of ArA in the prenatal and in post-natal nutritional provision by human milk makes a compelling case for re-evaluation of its role, especially in reproductive biology.

Background: Ectodermal dysplasias (EDs) are a large and complex group of disorders affecting the ectoderm-derived organs; the clinical and genetic heterogeneity of these conditions renders an accurate diagnosis more challenging. The aim of this study is to demonstrate the clinical utility of a targeted resequencing panel through enhancing the molecular and clinical diagnosis of EDs. Given the recent developments in gene and protein-based therapies for X-linked hypohidrotic ectodermal dysplasia, there is a re-emerging interest in identifying the genetic basis of EDs and the respective phenotypic presentations, in an aim to facilitate potential treatments for affected families. Methods: We assessed seventeen individuals, from three unrelated families, who presented with diverse phenotypes suggestive of ED. An extensive multidisciplinary clinical evaluation was performed followed by a targeted exome resequencing panel (including genes that are known to cause EDs). MiSeqTM data software was used, variants with Qscore >30 were accepted. Results: Three different previously reported hemizygous EDA mutations were found in the families. However, a complete genotype-phenotype correlation could not be established, neither in our patients nor in the previously reported patients. Conclusions: Targeted exome resequencing can provide a rapid and accurate diagnosis of EDs, while further contributing to the existing ED genetic data. Moreover, the identification of the disease-causing mutation in an affected family is crucial for proper genetic counseling and the establishment of a genotype-phenotype correlation which will subsequently provide the affected individuals with a more suitable treatment plan.

This paper presents a study of the complex permittivity of n - type copper indium selenide semiconductor compound at low temperatures down to −175 °C. Alternating current with frequency varying between 20 Hz and 1 MHz is applied to the material in order to measure the dielectric constant ɛ ′ and dielectric loss D = ɛ ″/ ɛ ′. ɛ ′ is found to decrease with temperature and frequency, whereas D decreases with frequency and increases with temperature. The experimental data of ɛ ″ agree with the expression ε ″ = A ω m ω , T ${\varepsilon }^{{\prime\prime}}=A{\omega }^{m\left(\omega ,T\right)}$ , where the frequency exponent m ( ω , T ), calculated through the relation m ω , T = ∂ ⁡ ln ε ″ / ∂ ⁡ ln ⁡ ω T $m\left(\omega ,T\right)={\left.\left(\partial \mathrm{ln}{\varepsilon }^{{\prime\prime}}/\partial \mathrm{ln}\omega \right.\right)}_{T}$ , shows a frequency and temperature dependence. The data are analyzed in light of existing theoretical models.

This paper reviews the main applications of the biopolymer chitosan, the main derivative of chitin, a material usually obtained from natural sources accessible at low cost, i.e., industrial wastes from fisheries. Due to its natural origin, which confers biodegradability and biocompatibility properties, in addition to its low toxicity, chitosan has been gaining attention in numerous sectors, such as agriculture, food, medicine, pharmaceuticals, etc., including also important oenological applications due to its potential as a green alternative to the use of sulphite. Among the many applications that can be generated from these materials in the wine-making area, their use has been reported for the clarification of must; in the preparation of films for the removal of contaminants, whether organics such as ochratoxin A or inorganics such as some metal ions and their salts; the control of turbidity caused by protein precipitation; the encapsulation of yeasts of oenological interest and enzymes for the control of adverse microorganisms such as Brettanomyces; the manufacture of sensors and nanosensors for the quantification of contaminants, the quality control of starting materials and final products, the optimisation of fermentation processes, the monitoring of storage conditions, etc. As a result of this review, significant development of the applications of this material in the oenological area can be expected, especially due to the possibilities of preparing new derivatives, including the great variety of these that have been recently proposed through click reactions, as well as the growing incursion of chitosan in nanobiotechnology.

In this paper, a mechanism for the generation of pseudo-random numbers with a very high level of randomness is proposed. The design of this mechanism is based on geometric structures simulated by software, specifically rotating cylinders that are activated, also, with random inputs produced by means of events of the electronic system on which it operates. Due to the random quality, its outputs can be used to implement robust systems for data protection.

Se ha documentado que la linfopenia es un marcador de gravedad y complicaciones en el paciente COVID-19. El objetivo fue determinar la linfopenia como parámetro de severidad en pacientes con infección por SARS-CoV-2, mediante un estudio observacional, analítico correlacional caso-control, en el cual se revisaron 140 historias clínicas. Se registraron variables sociodemográficas, clínicas de ingreso, de hospitalización, valores del hemograma y biomarcadores séricos. Las asociaciones estadísticas se estimaron mediante las pruebas Chi2 y t de student, además de ANOVA, R de Pearson y curvas de las características operativas del receptor (COR), considerando significativos valores de p<0,05. El género más frecuente fue el masculino. El grupo etario más afectado fue de 61-75 años. Las formas clínicas más sobresalientes fueron moderada y severa. Hubo diferencias entre las comorbilidades y días de hospitalización. Cuando se analizó la correlación del valor relativo de los linfocitos, no se encontraron fuerzas de asociación con las variables, solo con la forma de presentación clínica (r2: -,290) y el resultado final de la enfermedad, el valor de los linfocitos mostró mejor rendimiento para predicción del desenlace de la enfermedad. Se sugiere utilizar el valor relativo de linfocitos durante el manejo terapéutico paciente COVID-19

The preparation of monolayers based on an organic radical and its diamagnetic counterpart has been pursued on hydrogen-terminated silicon surfaces. The functional monolayers have been investigated as solid-state metal/monolayer/semiconductor (MmS) junctions showing a characteristic diode behavior which is tuned by the electronic characteristics of the organic molecule. The eutectic gallium-indium liquid metal is used as a top electrode to perform the transport measurements and the results clearly indicate that the SOMO-SUMO molecular orbitals impact the device performance. The junction incorporating the radical shows an almost two orders of magnitude higher rectification ratio (R(|J1V/J-1V|) = 104.04) in comparison with the nonradical one (R(|J1V/J-1V|) = 102.30). The high stability of the fabricated MmS allows the system to be interrogated under irradiation, evidencing that at the wavelength where the photon energy is close to the band gap of the radical there is a clear enhancement of the photoresponse. This is translated into an increase of the photosensitivity (Sph) value from 68.7 to 269.0 mA/W for the nonradical and radical based systems, respectively.

Comprender la violencia desde sus actores constituye un requerimiento fundamental, a partir del cual focalizar los esfuerzos asociados con la intervención preventiva y la predicción de conductas destructivas en el escenario escolar. En tal sentido, esta investigación responde a dos procesos interrelacionados, que se complementan en la tarea de caracterizar las actuaciones, conductas y actitudes que la víctima, el victimario y el tercero espectador (observador) adoptan en lo que se ha denominado el espiral de la violencia; lograr tal cometido implicó la revisión documental sobre el perfil de cada sujeto, el cual fue sustanciado con las aportaciones derivadas de una experiencia etnográfica con estudiantes de educación media general, pertenecientes a instituciones públicas ubicadas al occidente de Venezuela. Ambos procesos permitieron construir la identificación del perfil de cada componente de la triada de la violencia, mediante el análisis de las prácticas culturales, sociales e ideológicas nocivas que legitimadas, han configurado lo que actualmente se denomina la cultura de la violencia, factor de riesgo que además de vulnerar el desenvolvimiento positivo del clima escolar, atenta contra el bienestar psicosocial, el reconocimiento de la otredad y el respeto por la integridad humana. En conclusión, definir patrones de comportamiento en cada sujeto incurso en acoso escolar permite profundizar en los estilos de crianza, prácticas socioculturales y condiciones psicológicas que refuerzan el ejercicio del maltrato, su recepción pasiva y la indiferencia frente a las necesidades de auxilio y protección de quien padece sufrimiento.

Los estudios de postgrado, como parte de sus propósitos, precisan la formación de investigadores autónomos capaces de gestionar competitivamente el instrumental estratégico y teórico-metodológico propio de la disciplina de estudio a la que se encuentran afiliados; requerimientos que por su potencial epistémico permiten la comprensión de las complejas e intrincadas relaciones que entretejen la realidad. En tal sentido, este artículo como resultado de una revisión documental, integra diversas posiciones teóricas y miradas epistémicas en torno a los modos como opera el pensamiento en el proceso de producir conocimiento; su objetivo es caracterizar las actividades mentales que se orquestan y comprometen en la comprensión tanto de la realidad como del conocimiento acumulado. Parte de las reflexiones alcanzadas refieren a la necesidad de potenciar la dimensión cognitiva del participante de los estudios de postgrado, familiarizándolo con el compromiso de disponer su potencial cognitivo y el compromiso intelectual-académico de dar cuenta de las relaciones que hilvanan la realidad, desentrañando nexos en una inminente complejidad que demanda la disposición de la reflexividad, la criticidad y las habilidades propias del pensamiento superior como requerimientos para producir nuevas aportaciones teóricas, metodológicas y prácticas. Se concluye que, impulsar la actuación epistémica en los programas de postgrado implica impulsar experiencias que operativicen el pensamiento, que amplíen la construcción de aportaciones, así como la organización y sistematización de hallazgos.

It is widely known that hydrofluoric and sulfuric acids are the conventional catalysts used in the alkylation reaction, an important petrochemical process in the production of automotive fuels. However, these inorganic acids are highly toxic and therefore, solid zeolitic catalysts have emerged as an environmentally friendly alternative. In this work, a series of BEA-type zeolitic materials were prepared in hydrothermal systems varying the crystallization time to test their catalytic performance in the alkylation of isobutane with trans-2-butene. The materials were characterized by Infrared Spectroscopy (FT-IR), X-ray Powder Diffraction (XRPD), Scanning Electron Microscopy (SEM), N2 physisorption, and total acidity measurements by ammonia method. The synthesis of BEA zeolite was successfully carried out at crystallization times between 8 and 20 h (ZB-8, ZB-12, and ZB-20 samples), whilst longer periods produce a combination of BEA and MFI zeolites (ZB-28 and ZB-96 samples). Based on the XRPD analysis, the possible presence of two polymorphs of the BEA zeolite is proposed. The synthesized materials in the acidic form were catalytically examined for 120 min at different contact times (0.078, 0.156, and 0.234 gcat × min × mol⁻¹) and temperatures (40 and 60 °C). The reaction was fitted to second-order deactivation kinetics. High selectivity was observed for the group of C7-C9+ compounds in the steady-state condition, particularly towards the fraction of C8 compounds. The generation of the compounds that make up the alkylate group was favored in most catalytic tests. The highest yields for alkylate were achieved under conditions of 0.156 gcat × min × mol⁻¹ and 40 °C with values of 9.5 and 12 % for the ZB-12 and ZB-96 catalysts, respectively. This study supported the importance of balancing the density of acidic sites and the porous topology of zeolitic materials in conjunction with the selection of reaction parameters such as temperature and contact time to favor the yield towards alkylate.

Satisfying energy demand has become a global problem that is on the rise due to population growth, infrastructure deterioration, a decline in fossil fuel sources, high costs for investment, among others. Smart grids, in addition to those challenges that they have at the level of energy generation, have other management challenges derived from the great diversity of components that make them up, such as energy storage systems (batteries, capacitors, etc.), the different types of consumers (controllable, non-controllable loads) and prosumers (electric vehicles, self-sustaining buildings, micro-grid, etc.), among others. Consequently, a distributed control problem is presented, mainly oriented to the coordination of its components. A possible solution is to achieve the participation of each component when conditions are more favorable, such as prioritizing production with renewable energy sources, or taking advantage of prosumers so that they can meet local demand, among other things. Therefore, new strategies with a distributed approach such as bio-inspired emergent controls are necessary. The objective of this work is the specification of an emergent control approach to coordinate a smart grid. This approach allows the coordination of the energy supply in various operating scenarios. The results obtained demonstrate a perfect synchronization between the different smart grid components (agents), prioritizing renewable energy sources, regardless of the operational context (for example, in cases of failures, unsuitable environmental conditions, etc.).

In plant ecology, extreme environments are those that pose physiological or other limitations to plant growth, especially for non-adapted taxa. In these environments, the severity of climate conditions and/or the limitations imposed by particular soil substrates represent major selective pressures for plants, leading to the evolution of a wide array of functional traits, specific strategies and adapted taxa. In this special issue, we present a collection of papers that focuses on plants in various extreme environments, including the Arctic and Antarctic, regions with serpentine and gypsum soils, high mountain areas and deserts. The papers include a broad array of methods to study the ecology and evolution of plants in extreme environments, such as field surveys, greenhouse and field experiments, molecular phylogenetic analyses and/or physiological measurements. Overall, this special issue showcases research on how plants thrive in extreme environments which, in turn, may provide pointers to how plant communities might respond to living in increasingly challenging environments resulting from unprecedented land-use changes and climate warming at the present time and in the future.