4,301 research outputs found
Mario Fresa (Salerno, 1973)
No full textBilingual short anthology, in Italian and Spanish, of poems written by Mario Fresa
Potencial bioactivo de los residuos del cultivo de fresa (Fragaria x ananassa) en Costa Rica
No full textStrawberry fruit (Fragaria x ananassa) is a widely consumed food worldwide and has been characterized to have a wide range of beneficial properties for human health, mostly associated with its antioxidant potential. The search for bioactive phytochemicals in strawberry has focused mainly on the fruit, while the biochemical profile of the leaves has been little studied and continues to be underutilized, despite being a potential source of bioactive metabolites that could be used in the formulation of food, industrial and pharmaceutical products. In addition, higher bioactive polyphenol content has been reported in strawberry leaves than in the fruit, and strawberry leaves could also be an important source of ellagic acid, a bioactive antioxidant compound, which is limited in the human diet but has great biomedical potential. This literature review aims to evaluate the information available on the characteristics of strawberry crops (Fragaria x ananassa) in Costa Rica, targeting towards the comprehensive use of the agro-industrial residues of this plant. The information reviewed confirmed that the commercialization of strawberry cultivation focuses on the fruit, while the leaves and the rest of the plant's vegetative material are discarded periodically, but could be incorporated into new production chains. Such strategies are especially important for small developing countries with agricultural-based economies, to improve the use of agro-industrial waste and provide added value to crops, aiding both the environment and human health.El fruto de la fresa (Fragaria x ananassa) es un alimento ampliamente consumido a nivel mundial, y al cual se le han atribuido una amplia gama de propiedades beneficiosas para la salud humana, mayoritariamente asociadas a su potencial antioxidante. La búsqueda de fitoquímicos bioactivos en la fresa se ha enfocado en el fruto, mientras que el perfil bioquímico de las hojas ha sido poco estudiado y sigue siendo poco aprovechado, a pesar de constituir una fuente potencial de metabolitos bioactivos que podrían ser utilizados en la formulación de productos para el sector alimenticio, industrial y farmacéutico. Además, se ha reportado mayor contenido de polifenoles bioactivos en las hojas de fresa que en el fruto, y las hojas de fresa podrían ser una fuente importante de ácido elágico, un compuesto antioxidante bioactivo poco abundante en la dieta humana pero de gran potencial biomédico. Este artículo de revisión bibliográfica tiene como objetivo evaluar las características del cultivo de fresa (Fragaria x ananassa) en Costa Rica, con miras al aprovechamiento integral de los residuos agroindustriales de este cultivo. La información consultada demostró que la comercialización del cultivo de fresa se enfoca en el fruto, mientras que las hojas y el resto del material vegetativo de la planta se descartan periódicamente, y podrían ser incorporados en nuevas cadenas productivas. Este tipo de estrategias son de especial importancia para países pequeños en desarrollo y con economías de base agrícola, para mejorar el aprovechamiento de los residuos agroindustriales y darles un mayor valor agregado a los cultivos, en beneficio del ambiente y la salud humana
Caracterización de fracciones polifenólicas de la fresa y sus implicaciones tecnológicas
No full textSe ha estudiado la composición de las fracciones antociánica y flavanólica de la fresa, así como las reacciones que los componentes más representativos de las mismas pueden sufrir en disoluciones modelo y en mermeladas y su influencia sobre la estabilidad del color de estos medios. Asimismo, se han realizado ensayos preliminares de intervención tecnológica encaminados a mejorar la estabilidad del color en mermeladas de fresa. El estudio de las fracciones fenólicas se realizó en cinco variedades de fresa (cv. Camarosa, Eris, Carisma, Oso Grande y Tudnew) utilizando métodos de análisis optimizados por HPLC con detección por espectrofotometría de diodos (DAS) y espectrometría de masas (MS). Se pudo así detectar la presencia en la fresa de treinta y un antocianos diferentes y establecer con cierta seguridad la identidad de la mayoría de ellos, algunos descritos por primera vez en este trabajo. Particularmente interesante fue la detección de cuatro pigmentos con una estructura correspondiente a dímeros de condensación flavanol-antociano. Igualmente, se determinó la composición en flavanoles mayoritarios de la fresa.
Los ensayos modelo realizados con pelargonidina 3-glucósido, antociano ampliamente mayoritario en la fresa, permitieron comprobar que la disponibilidad de oxígeno era el factor con más influencia sobre la estabilidad del antociano en disolución acuosa, mientras que la presencia de azúcares sólo mostraba un pequeño efecto protector frente las reacciones que conducían a su desaparición, y los flavanoles constituían un factor desestabilizante, en las condiciones de ensayo utilizadas. La cinética de desaparición del antociano se ajustaba inicialmente a un proceso de primer orden, cuya pendiente se encontraba influida por la composición del medio. Los análisis por HPLC-DAS-MS permitieron establecer la identidad de algunos de los principales productos formados en la degradación del antociano y de su reacción con flavanoles.
Se comprobó que la incorporación de ácido pirúvico o de acetaldehído durante la elaboración de mermeladas conduce a una desaparición acelerada de antocianos y formación de nuevos pigmentos. En particular, el ácido pirúvico induce la formación de piranoantocianos, con un color más anaranjado y mayor estabilidad que los antocianos originales, haciendo que el color del producto permanezca más estable durante el almacenamiento que el de una mermelada convencional. Por su parte, el acetaldehído favorece la condensación con flavanoles, con formación de pigmentos con tonalidad más azulada que los antocianos, que progresan rápidamente hacia estructuras complejas, dando lugar a un producto con un color inadecuado e inestable.Comissão Europeia (Fundo Social Europeu) e Governo Português através do Programa PRODEP (III) - ref.ª 5.3/N/199.006/00-Doutoramento; Fabrica de Dulces y Conservas Helios (Valladolid, Espanha)
Effects of Dynamical Information in Identification Problems in Electromagnetics
No full textThe identification of currents from external magnetic
measurements is an inverse problem frequently encountered in a
number of applications. This inverse problem can be regularized
with SVD decomposition, but other information coming from the
dynamical behavior of the system can be beneficial. In the paper
such an approach is analyzed and compared to classical methods
EX-VESSEL MAGNETIC MEASUREMENTS IN JET: A CRITICAL ASSESSMENT OF THE COLLAR PROBE
No full textThe paper reviews a set of magnetic probes which was installed in JET in order to improve the field measurements
in the proximity of the iron, and focuses in particular on one of them. The set consists of six Limb probes, attached
to the upper horizontal iron yokes, and one Collar Probe, inserted in the collar region of the iron structure. The
probes include pick-up coils, flux loops, Hall sensors, and a temperature sensor.
The data provided by the system are regularly acquired and recorded within the set of JET Pulse Files. They
can be used in studies implying measurement of the stray field due to the residual magnetization, as well as for all
the modeling activities involving 3D studies, in particular resistive wall mode studies, more accurate modeling for
the vertical stabilization, interactions between NBI and magnetic field. In addition, the experience gained with
Hall transducers is considered valuable in view of their potential use in ITER.
Unlike the limb probes, the collar probe did not pass the functional commissioning, due to an unexpected
discrepancy between the signals from Hall sensors and pick-up coils. The analysis illustrated in the paper shows
that a critical assessment of the local configuration and a suitable magnetic modeling solve the issue of the
observed discordance, by putting it in relation with a local geometrical effect due to the peculiar shape of the
ferromagnetic collar teeth.
The improvement of magnetic models targeted to the prediction of signals produced by magnetic sensors
is important, also considering that a large number of magnetic probes in ITER will be located close to the
ferromagnetic inserts
Integral boundary conditions in F.E.M approaches with the minimization of constitutive error
No full textA method based on the minimization of the constitutive error has been successfully applied to finite element formulations of Maxwell equations. Error based techniques present a number of appealing characteristics, including the possibility of providing an estimation of the error distribution and to split the equation system in two decoupled subsystems. However, except for very simple cases, a direct numerical translation of the boundary conditions can cause a number of drawbacks: on one side the lack of symmetry and positive definition of the matrix, on the other side the impossibility of splitting the unknowns. This paper is aiming to discuss the problem and to propose a technique to effectively impose a wide class of boundary conditions within the framework of error based formulations. To show the performance of the technique, some examples are proposed
Optimization of the Power Supply Demand for Plasma Shape Control in a Tokamak
No full textWe focus on the estimation of the minimum poloidal field coil voltages for the plasma shape control in a tokamak. For given coil locations and for a class of disturbances we propose a procedure for the evaluation of the minimum voltages needed to guarantee that the plasma boundary displacement remains within specified limits. The impact of this problem on the minimization of the power supply cost is discussed for the case of the International Thermonuclear Experimental Reactor (ITER
Electromagnetic Analysis of a ITER superconducting coil Using Three-Dimensional Integral Formulation
No full textUse of Compensation Theorem for the Robustness Assessment of Electromagnetic Devices Optimal Design
No full textIn the optimal design of electromagnetic devices, the robustness is a critical aspect. In the modern robust optimization procedures, the evaluation of suitable partial derivatives is required to define sensitivity at each step of the search process; the estimate of the sensitivity is required also in non robust design if the robustness of the final configuration must be assessed with respect to a number of independent parameters. More generally, the tolerance analysis is a widely adopted tool in the analysis of electromagnetic devices, whose main aim is to assess the impact of some independent uncertain parameters (e.g. geometrical dimensions or materials properties) on a device performance as, for example, the electromagnetic field in a volume of interest.
In both cases - robust design and tolerance analysis - if assuming a linear behavior of the system, a number of simplified approaches can be adopted to compute the effect of “deformations” starting from knowledge of nominal solution. One of the best known is the compensation theorem, which will be discussed with some detail in the paper, but other techniques, suited for particular numerical models, can also be exploited to simplify computations. An example of such possibilities will be discusse
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