Population dynamics of phyllocnistis citrella (Lepidoptera: Gracillariidae) and its parasitoids in Tafí Viejo, Tucumán, Argentina

Seasonal abundance of the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), was investigated between Nov 1999 and Apr 2003 in Tafí Viejo (Tucuman province). Phyllocnistis citrella populations increased during spring and summer, declined during fall, and disappeared in the winter. Five species of parasitoids, one exotic and four indigenous, attacked citrus leafminer immature stages in commercial and experimental lemon orchards. Ageniaspis citricola Logvinovskaya (Hymenoptera: Encyrtidae) was the most abundant parasitoid. Cirrospilus neotropicus Diez & Fidalgo (Hymenoptera: Eulophidae) was the most abundant indigenous species, followed by Galeopsomyia fausta LaSalle (Hymenoptera: Eulophidae). The other indigenous species were not common and were only occasionally collected from citrus leafminer larvae. Parasitoids and P. citrella exhibited similar population fluctuations throughout the entire sampling period. A certain degree of synchrony exists between the most abundant parasitoids (A. citricola, C. neotropicus, and G. fausta) and the pest. The highest rates of parasitism were observed in the fall. Ageniaspis citricola exhibited approximately 29.5% parasitism, whereas all the native species together were only 8.2%. Data showed that a clear dependence existed between percentages of parasitism and citrus leafminer population density for the most frequent parasitoid populations. The results of this study show that C. neotropicus has an important role among the native species present in Argentina.Fil: Diez, Patricia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; ArgentinaFil: Peña, Jorge E.. University of Florida; Estados UnidosFil: Fidalgo, Patricio. University of Florida; Estados Unido

Cytochemical localization of acid phosphatase in Stigeoclonium tenue (Chaetophorales, Chlorophyceae)

Nonspecific acid phosphatases are a group of enzymes whose activity increases the availability of exogenous and endogenous orthophosphate either through extra- or intracellular hydrolysis of phosphate compounds. Our study demonstrates the activity of acid phosphatases in the filamentous freshwater alga Stigeoclonium tenue. These enzymes were detected following a cerium-based method in which cerium was used as an orthophosphate-capture reagent. In thalli from S. tenue from the natural environment, acid phosphatases were found in the longitudinal cell wall, plasmalemma, and vacuole. In thalli from Bold’s Basal Medium culture, these enzymes were found mainly in the plasmalemma; they were scarce in the cell wall. In the thalli grown in phosphate-enriched culture medium, enzymes were found only in the plasmalemma. The low availability of orthophosphate in the medium seems to induce the transport of these enzymes to the cell wall. Its abundance, on the contrary, seems to attenuate this response without affecting the localization of acid phosphatases in the plasmalemma.Fil: Michetti, Karina Mariel. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ficología y Micología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leonardi, Patricia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Caceres, Eduardo Jorge. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ficología y Micología; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

On the reduction of 4-oxo-4h-benzopyran-3-carbaldehydes : global and local electrophilicity patterns

The theoretical global and local electrophilicity patterns of substituted and chelated 4-oxo-4H-benzopyran-3-carbaldehydes (formylchromones) have been evaluated using the electrophilicity index proposed by Parr et al [J. Am. Chem. Soc. 1999, 121, 1922]. The complexation of formylchromones with aluminum predicts a strong electrophilic character of these compounds against nucleophiles. Local response at the active sites may also be assessed in terms of a global contribution described by the global electrophilicity, and a local contribution described by the variations in electrophilic Fukui function at those sites. The highest local electrophilicity is found at the formyl group of the chelated formylchromones, in spite of that, the highest positive charge is located on the pyrone carbonyl group. This result is consistent with the experimental observed reactivity displayed by 4-oxo-4H-benzopyran-3-carbaldehydes in the presence of 2-propanol and alumina

Tautomeric Equilibria Studies by Mass Spectrometry

Tautomerism in organic chemistry has been extensively studied in condensed phase by spectrometric methods, mainly by IR and NMR techniques. Mass spectrometry studies start 40 years ago but just recently it has been recognized the importance of the mass spectral data for the study of tautomerism in the gas phase.
Mass spectrometry can provide valuable information in regard to tautomeric equilibria when studying mass spectra among the members of different families of organic compounds.
The relevance of the mass spectral data resides on several facts but there are two that are of key importance:
1-	Mass spectral fragmentation assignments should be tautomer specific since the corresponding abundances ratios are supposed to be correlated to the keto/enol contents.
2-	Ionization in the ion source is supposed to have no effect on the position of the equilibrium so that the results reflect the tautomers content in the gas phase previous to ionization.
Some of the carbonylic compounds do not exhibit noticeable tautomerism so the fragment abundances assigned to the enol form is very low or not measurable. Since enolization is more noticeable in the case of thio-derivatives (which correlates adequately with the oxygenated analogues), the study of their mass spectra is an interesting choice to reach some degree of generalization. 
In addition, experimental findings are supported by semiempirical theoretical calculations, which probed to be adequate not only for supporting tendency correlations among the members of a compound family but also to calculate heats of tautomerization in gas phase.
Reports using mass spectrometry for tautomerism are becoming less common. One of the reasons is that now it would appear that the interpretation of MS results is not as straightforward as it was once believed, even though in a recent review it was written that: “Mass spectrometry is the most informative and practical method for studying and identifying tautomers in the gas phase” [1]. 
In fact, mass spectrometry seems to be very informative for studying and identifying tautomers, because in this case external factors like solvents, intermolecular interactions, etc., can be excluded by transferring the tautomeric system into gas phase, where the process becomes truly unimolecular [1].
This review covers the study of Tautomerism by Mass Spectrometry in the last four decades. 
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Nutrient pollution of waters: eutrophication trends in European marine and coastal environments

En els darrers cinquanta anys, l'eutrofització (l'enriquiment natural o artificial de nutrients d'un ecosistema aquàtic) ha esdevingut un problema de contaminació ambiental àmpliament estès, a causa de l'augment de la població i de les àrees urbanes, així com de l'augment de producció en els sectors agrícoles i ramaders. Tot i que aquest problema és d'especial importància en els països desenvolupats i en zones d'elevada població, la implantació de sistemes d'agricultura intensiva en zones en desenvolupament (com els països de l'Est d'Europa), pot dur a la propagació de l'eutrofització en poques dècades. L'any 2004, per tal d'establir un nombre reduït d'indicadors estables, però que puguin mostrar tendències temporals i espacials, i que responguin a qüestions prioritàries de política ambiental, l'Agència Europea del Medi Ambient (EEA) va identificar un conjunt de 37 indicadors que cobreixen sis àrees ambientals i quatre sectors prioritaris respecte als quals es dirigeixen les estratègies de l'EEA. En aquest treball, l'avaluació de la informació facilitada per quatre indicadors seleccionats permet valorar la situació actual respecte a l'eutrofització als mars europeus. Es conclou que, tot i la creixent implantació de les directives europees dirigides a la millora de la qualitat del sistemes aquàtics, no s'ha observat en termes generals una reducció de l'eutrofització. Aquest fet emfatitza la lenta recuperació dels ecosistemes perjudicats per l'acció humana.In the last 50 years, eutrophication (the natural or artificial nutrient enrichment of an aquatic ecosystem) has become a widespread environmental pollution problem due to the growing population, rapid urbanization of previously rural areas, and increased agricultural and livestock production. Even though this problem has particular relevance in developed countries and in areas with large populations, the implementation of intensive agriculture systems in developing zones (such as in Eastern Europe) may lead to the further propagation of the eutrophication in the coming decades. In 2004, the European Environment Agency (EEA) set out to answer to certain priority policy questions. For this purpose, it selected a small number of relevant indicators that are stable but sensitive to temporal and spatial trends. The core set of 37 indicators (referred to as CSI) covers six environmental subjects and four sectors that reflect the priorities of the EEA. In this work, the information rendered by four of the 37 selected CSI was used to assess the current state of eutrophication in European seas. The analysis showed that, despite implementation of those EU Directives aimed at improving the quality of aquatic environments, no general reduction in eutrophication has occurred. This fact emphasizes the slow recovery rate of ecosystems damaged by human actions

Effect of isolation conditions on structural properties and surface behavior of soy-whey proteins

In this study, the impact of isolation conditions on structural and surface properties at the air/water interface of soy-whey proteins (SWP) was assessed. SWP were obtained by precipitation of soy-whey (at pH 4.5 or 8.0) with acetone or ammonium sulfate. Despite the fact that all SWP samples exhibited similar electrophoretic patterns, they showed different protein content (from 54.2 to 98.2% w/w). When precipitation was performed at pH 4.5, SWP samples evidenced a decrease of protein solubility (SP) and thermal stability, while the precipitation with acetone promoted the enrichment in polysaccharides and minerals. For all samples, intrinsic fluorescence, surface hydrophobicity and Fourier transform infrared (FTIR) studies revealed structural changes correlated to protein unfolding and aggregation processes. However, the surface behavior can be predicted from these studies mainly due to differences in surface hydrophobicity and the differential contribution of insoluble aggregates. The heating of SWP samples enhanced the surface activity, regardless of the pH of the raw material and the isolation method. These results can be useful as a reference research and as a starting point for industrial exploitation of proteins from soy wastewater.Fil: Ingrassia, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Sobral, Pablo Antonio. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Risso, Patricia Hilda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Palazolo, Gonzalo Gastón. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Investigación en Funcionalidad y Tecnología de Alimentos; ArgentinaFil: Wagner, Jorge Ricardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Investigación en Funcionalidad y Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Protective and family risk factors related to adolescent drug use

Se trata de un estudio transversal, cuantitativo, cuyo objetivo fue verificar los factores familiares protectores y de riesgo relacionados al consumo de drogas en adolescentes, considerando los patrones de interacción que se desarrollan en la familia, sus grados de adaptabilidad y vulnerabilidad. Participaron del estudio 80 adolescentes de género femenino, del 1º al 4º año de la Enseñanza Media, que respondieron a un cuestionario. Se establecieron los factores de riesgo y protección de mayor relevancia que estarían influyendo en esta situación, tales como, patrones de interacción, grado de adaptabilidad, modo de afrontamiento de los problemas, recursos de la familia y valores. Los factores de mayor riesgo fueron el modo de enfrentar los problemas, y dentro de estos, la falta de apoyo religioso y la búsqueda de apoyo profesional, conjuntamente con las dificultades de comunicación intrafamiliares. Los de menor riesgo fueron los valores, como el esfuerzo personal. Los resultados obtenidos resaltan que el enfermero debe asumir como parte de su rol las intervenciones psicosociales, especialmente en la población escolar, ya que así estarían actuando como agentes de prevención del consumo de drogas.Este é um estudo transversal, quantitativo, cujo objetivo foi verificar os fatores protetores e de riscos familiares, relacionados ao consumo de drogas em adolescentes, considerando os padrões de interação que se desenvolvem na família, seus graus de adaptabilidade e vulnerabilidade. Participaram deste estudo 80 adolescentes do sexo feminino, do 1º ao 4º ano do ensino médio, que responderam a um questionário. Foram estabelecidos os fatores de risco e de proteção mais relevantes que podem influenciar a situação, como os padrões de interação, grau de adaptabilidade, modo de enfrentamento dos problemas, os recursos da família e valores. Os fatores de maior risco foram o modo de enfrentar os problemas e, dentro desses, a falta de apoio religioso e apoio profissional, juntamente com as dificuldades de comunicação dentro das famílias. Os de menor risco foram os valores, como o esforço pessoal. Os resultados evidenciaram que os enfermeiros devem assumir, como parte de seu papel, as intervenções psicossociais, especialmente entre a população escolar, uma vez que atuariam como agentes na prevenção do uso de drogas.This cross-sectional and quantitative study aimed to verify the family's protective and risk factors related to drugs use in adolescents, considering the interaction patterns developed in the family, their degree of adaptability and vulnerability. Participants in this study were 80 female adolescents, from the 1st to 4th grade of high school, who answered a questionnaire. The most relevant risk and protective factors that would influence the situation were established, such as patterns of interaction, degree of adaptability, way of coping with problems, family resources and values. The major risk factors that emerged were the way people confront problems and, within these, lack of religious support and professional support, besides communication difficulties within families. The lowest risks were values, such as personal effort. The results highlight that nurses should assume psychosocial interventions as part of their role, especially among school-age children as, thus, they would be acting as agents in the prevention of drugs use

Deficiencia en la habilidad de resolver problemas matematicos

Este trabajo de investigación pretende sistematizar el Proceso Docente Educativo de la asignatura matemáticas del curso de ingreso para las ingenierías básicas de la ESPOL de manera que sea un proceso desarrollador de habilidades generales y específicas de la asignatura. Se validó el problema mediante un sistema de expertos, los que coincidieron en lo importante que es desarrollar la habilidad de resolver problemas, la que requiere del desarrollo de habilidades del pensamiento lógico. Para dar solución al problema, se planteó el diseño de un sistema de tareas tomando en consideración los estilos de aprendizaje de los estudiantes y la opinión de estudiantes de la ESPOL que ya han cursado materias como Cálculo I y Álgebra Lineal. El sistema de tareas propuesto contiene problemas de familiarización, reproducción y producción. Con los problemas de familiarización los estudiantes se ejercitan y desarrollan las habilidades de definir y describir; con los problemas de reproducción practican y desarrollan las habilidades de observar, identificar, relacionar y con los problemas de producción, en los que se requiere de un nivel mas elevado del pensamiento lógico, se desarrollan habilidades como la de aplicar, clasificar, relacionar, interpretar, etc. La validación de la propuesta se la hizo comparando los resultados de los exámenes de uno de los paralelos bajo mi coordinación, en donde se aplicaron métodos activos de aprendizaje, distintos a los aplicados en los demás grupos