LA APLICACIÓN DE LA NIIF PARA LAS PYMES EN TINGO MARÍA: PROBLEMÁTICA Y PERSPECTIVAS DE MEJORA

El propósito del presente estudio es conocer la problemática de la aplicación de la NIIF para las PYMES en Tingo María y determinar sus perspectivas a futuro. Para tal efecto, se aplicó un cuestionario de encuesta con 19 ítems a 29 asesores contables de 29 pequeñas y medianas empresas consideradas como principales contribuyentes. Asimismo, se aplicó una guía de entrevista dirigida a funcionarios miembros del Consejo Normativo de Contabilidad y a expertos en temas referidos a la aplicación e implementación de la NIIF para las Pymes. Los resultados indican que la problemática identificada en la aplicación de la NIIF está asociada a la inexistencia de un ente rector que realice funciones de supervisión (Chi2 29; sig. ,000) y a la deficiente capacitación en NIIF por parte de los asesores contables (Chi2 14,58; sig. ,000)

Comparación de estrategias de control para sistemas MPPT: optimización de la potencia entregada a la carga vs optimización de la potencia extraída del generador fotovoltaico

Los sistemas de seguimiento del punto de máxima potencia (MPPT) tratan de maximizar el rendimiento de una instalación fotovoltaica mediante el ajuste dinámico del ciclo de trabajo (δ) del convertidor CC/CC empleado para conectar el generador con la carga. Tradicionalmente, el algoritmo de control empleado para la definición del ciclo de trabajo determina el valor de este parámetro con objeto de maximizar la potencia generada por el generador fotovoltaico. Estas técnicas no tienen en cuenta el carácter no ideal del convertidor CC/CC, cuyo rendimiento real depende también del ciclo de trabajo (δ) con el que opera. Considerando las características del convertidor CC/CC no puede afirmarse, a priori, que el método que optimiza la generación de potencia del generador fotovoltaico maximiza también la entrega de potencia en la carga, objetivo final de un sistema MPPT. Este trabajo adapta el ampliamente extendido algoritmo "Perturbación/Observación, P&O" para optimizar la entrega de potencia en la carga, midiendo las variables que determinan el comportamiento del algoritmo a la salida del convertidor CC/CC, y compara el rendimiento obtenido con el que se obtiene con el planteamiento clásico de optimización de la potencia entregada por el generador fotovoltaico, en el que la medida de las variables que determinan el funcionamiento del algoritmo se realizan en la entrada del convertidor CC/CC. Se ha analizado un sistema fotovoltaico que emplea un convertidor boost para conectar el generador fotovoltaico (PVG) con la carga, el cual ha sido sometido a condiciones atmosféricas variables, en cuanto a radiación y temperatura, y a distintos requerimientos de consumo de carga, obteniendo los rendimientos ofrecidos por el sistema para las dos filosofías de control. Estos resultados se discuten para determinar si hay una pérdida significativa de rendimiento en el planteamiento clásico frente a la nueva propuesta y la conveniencia de desarrollar sistemas que optimicen la potencia útil, esto es, la entregada a la carga.The maximum power point tracking systems (MPPT) try to maximize the performance of a photovoltaic installation by dynamically adjusting the duty cycle (δ) of the DC/DC converter used to connect the generator to the load. Traditionally, the control algorithm used to define the duty cycle determines the value of this parameter in order to maximize the power generated by the photovoltaic generator. These techniques do not take into account the non-ideal character of the DC/DC converter, whose real efficiency also depends on the duty cycle with which it operates. Considering the characteristics of the DC/DC converter can not be said, a priori, that the method that optimizes the power generation of the photovoltaic generator also maximizes the power delivery in the load, the final objective of an MPPT system. This work adapts the well-known algorithm "Perturbation / Observation, P&O" to optimize the delivery of power in the load, measuring the variables that determine the behavior of the algorithm at the output of the DC / DC converter, and compares its performance with the performance that it is obtained with the classical approach of optimizing the power delivered by the photovoltaic generator, in which the measurement of the variables that determine the operation of the algorithm are made at the input of the DC / DC converter. A photovoltaic system that uses a boost converter to connect the photovoltaic generator with the load has been analyzed, which has been subjected to variable atmospheric conditions, in terms of radiation and temperature, and to different load consumption requirements, obtaining the performances offered by the system for the two control philosophies. These results are discussed to determine if there is a significant loss of performance in the classical approach with respect to the new proposal and the convenience of developing systems that optimize the useful power, that is, the power delivered to the load

APLICACIONES BIOMÉDICAS, TEXTILES Y ALIMENTARIAS DE NANOESTRUCTURAS ELABORADAS POR ELECTROHILADO

Se ha implementado el uso de nuevas nanoestructuras y técnicas que permitan producir nanopartículas para su aplicación en diversos sectores con la finalidad de mejorar los procesos e incrementar la productividad. Una de éstas es el método de electrohilado ó electrospinning, teniendo la característica de ser sencillo, de bajo costo y utilizar una gran variedad de materiales, convirtiéndolo en uno de los más utilizados. Las estructuras obtenidas poseen características únicas, entre ellas su gran área de contacto y alta porosidad. Debido a estas propiedades, las nanofibras presentan gran interés para ser aplicadas en diferentes áreas, como son la biomédica, textil y de alimentos obteniendo resultados benéficos

Tomato plant extract (Lycopersicon esculentum) obtained from agroindustrial byproducts and its antifungal activity against Fusarium spp.

Phytopathogenic fungi are a constant danger in the production of different crops around the world, especially in melons, since they can cause significant economic losses during the harvest, affecting the quality and shelf life. In recent years, producers have increasingly used chemical pesticides indiscriminately, causing environmental problems and damage to public health. For this reason, phytopathogenic fungi become more resistant. However, it is essential to guarantee the safety, quality, and shelf life of food after harvest, during transportation, storage and marketing. The presence of fungi in food can cause diseases transmitted through the production of toxins. Most producers depend on the discriminated use of chemical pesticides, which is a great challenge to guarantee food safety and sustainable agricultural production. To solve this problem, some extracts derived from tomato plants after harvest containing bioactive compounds have been implemented. These compounds can be natural antifungal agents as they contain phenols, flavonoids, and vitamins. Bioactive compounds emerge as a sustainable and safe opportunity in the search for new antifungal and antimicrobial agents. Therefore, the objective of this study was to determine the in vitro antifungal activity of whole tomato plant extracts on three phytopathogenic fungi. The research findings indicated that a concentration of 74.7 μg/mL of TPE resulted in a complete inhibition of mycelial growth in Fusarium oxysporum, Fusarium graminearum, and Fusarium verticillioides. Additionally, TPE exhibited both fungistatic and fungicidal effects on these Fusarium species, with a MIC50 of 30.7, 31.5, and 29.5, and a MFC of 82.4, 78.6, and 75.8 μg/mL, respectively. As a result, this study suggests that TPE can be considered as an environmentally friendly solution for extracting tomato plants, which can be applied to the surface of whole fruits or incorporated into semi-processed foods

Partial Characterization of a Low-Molecular-Mass Fraction with Cryoprotectant Activity from Jumbo Squid (Dosidicus gigas) Mantle Muscle

Zamrzavanje utječe na funkcionalnost proteina ribe uslijed njihove denaturacije i agregacije. Usprkos tome, funkcionalnost strukturnih proteina Humboldtove lignje (Dosidicus gigas) ostaje ista i nakon zamrzavanja, vjerojatno zbog prisutnosti spojeva male molekularne mase s krioprotektivnim svojstvom. Zbog toga smo pomoću Fourier transformirane infracrvene spekroskopije (FTIR) ispitali frakciju male molekularne mase (<1 kDa) koja je topljiva u vodi, izdvojenu iz plašta Humbodtove lignje. Iz dobivenih spektara određeni su maseni udjeli ukupnih ugljikohidrata, slobodnih monosaharida, slobodnih aminokiselina i amonijevog klorida. Svojstvo krioprotekcije i kriostabilnost proteina kojima pridonose spojevi male molekularne mase ispitani su diferencijalnom pretražnom kalorimetrijom. Djelomičnom je karakterizacijom utvrđeno da su glavni sastojci frakcije bili: slobodne aminokiseline (18,84 mg/g), ugljikohidrati (67,1 µg/mg), među kojima i monosaharidi (ukupno 51,1 µg/mg glukoze, fukoze i arabinose), te amonijev klorid (220,4 µg/mg). Najzastupljenije aminokiseline bile su: arginin, sarkozin i taurin. Spojevi male molekularne mase, u masenom udjelu u kojem su prirodno prisutni u plaštu lignje, snizili su ledište vode na -1,2 °C, te povećali temperaturu kristalizacije na 0,66 °C. Stabilnost miofibrilarnih proteina nakon zamrzavanja i odmrzavanja bitno je povećana u prisutnosti spojeva male molekularne mase u usporedbi s kontrolom (proteinima mišića iz kojih su izdvojeni spojevi male molekularne mase), što potvrđuje kriostabilizacijsko svojstvo strukturnih proteina lignje. Osmoliti prisutni u frakciji male molekularne mase inhibirali su denaturaciju i agregaciju proteina te rekristalizaciju leda, čime je održana struktura mišića pri zamrzavanju. Spojevi male molekularne mase pridonijeli su kriostabilnosti mišića čak i pri njihovom malom masenom udjelu.Freezing conditions affect fish muscle protein functionality due to its denaturation/aggregation. However, jumbo squid (Dosidicus gigas) muscle protein functionality remains stable even after freezing, probably due to the presence of low-molecular-mass compounds (LMMC) as cryoprotectants. Thus, water-soluble LMMC (<1 kDa) fraction obtained from jumbo squid muscle was evaluated by Fourier transform infrared spectrometry. From its spectra, total carbohydrates, free monosaccharides, free amino acids and ammonium chloride were determined. Cryoprotectant capacity and protein cryostability conferred by LMMC were investigated by differential scanning calorimetry. Fraction partial characterization showed that the main components are free amino acids (18.84 mg/g), carbohydrates (67.1 μg/mg) such as monosaccharides (51.1 μg/mg of glucose, fucose and arabinose in total) and ammonium chloride (220.4 μg/mg). Arginine, sarcosine and taurine were the main amino acids in the fraction. LMMC, at the mass fraction present in jumbo squid muscle, lowered the water freezing point to –1.2 °C, inhibiting recrystallization at 0.66 °C. Significant myofibrillar protein stabilization by LMMC was observed after a freeze-thaw cycle compared to control (muscle after extraction of LMMC), proving the effectiveness on jumbo squid protein muscle cryostability. Osmolytes in LMMC fraction inhibited protein denaturation/aggregation and ice recrystallization, maintaining the muscle structure stable under freezing conditions. LMMC conferred protein cryostability even at the very low mass fraction in the muscle