ABSTRACT: Multiplex 330 (MX) is a portable, non-invasive fluorescence sensor that provides different multiparametric indices that are sensitive to the concentration of chlorophylls, flavonols, and anthocyanins on the leaf surface. This study investigated the use of these indices to assess the variability on free volatile composition of grapes (Vitis vinifera L.) in the field as well as other components of their quality potential in vineyards affected by iron deficiency chlorosis (IDC). Twenty non-irrigated Tempranillo/110 Richter vineyard subzones from non-affected to moderately affected by IDC were monitored in Ribera del Duero area (Spain) during two seasons. The results indicated that MX can characterize the spatial variation of leaf pigment concentrations, agronomic performance, and grape quality in vineyards affected by IDC. The MX indices measured at the leaf level close to harvest had better predictive values for the concentrations of free alcohols, volatile acids, C13-norisoprenoids, esters and acetates in the must than vine vigor, size or degree of technological maturity of the grapes. Our study demonstrates that the MX indices to estimate leaf pigment concentrations can be helpful to assess the technological maturity and free volatile composition of wine grapes in vineyards affected by IDC; nevertheless, the efficacy of the indexes may vary according to the year season.

ABSTRACT: Water deficit and iron nutritional deficiency (iron chlorosis) are frequent environmental stresses affecting grapevine production in the Mediterranean region. The objectives of this work were (i) to study the combined effects of both stresses on aromatic profile of Tempranillo grapes, occurring simultaneously in the vineyard, and (ii) to evaluate the viability of foliar chlorophyll content at veraison (Chl) to early assess aromatic quality potential of grapes in those conditions. Twenty non-irrigated vineyard subzones (10 m × 10 m each), affected and non-affected by iron chlorosis, were monitored in Ribera del Duero Appellation of Origin (North-Central Spain) during two consecutive seasons. Factorial ANOVA was performed to study the effects of predawn leaf water potential and Chl measured at veraison on the must composition parameters and, specifically, on the concentrations of free and bound aromatic compounds. Water deficit tended to increase color intensity and extractable anthocyanin content of the grapes, whereas the incidence of iron deficiency enhanced total phenolic compound content within subzones with better water status. More water or iron stressed subzones restricted C6-alcohols contents than less stressed subzones. Without significant effects on vine vigor, yield or berry size, the incidence of iron chlorosis increased the concentrations of some specific terpenes, C13-norisoprenoids, volatile acids and volatile phenols. These results showed that low to moderate iron stress can have positive effects on grape aromatic quality, and demonstrated that Chl can be a useful tool in precision viticulture to map the aromatic potential within rainfed vineyards affected by iron chlorosis.

In order to improve the learning process of Numerical Methods in college students racing Mathematics, School of Exact and Natural Sciences, Universidad Nacional de Mar del Plata (Argentina), we have decided to investigate the possible causes that adversely affect academic performance. Therefore, we have noticed a need to pay attention to students' attitudes, mainly on the grounds that they may have an important influence on the short-term academic performance. The research involved a design stage, a pilot test, instrument validation and an analysis of the coherence of responses by classifying clusters based on variables, a descriptive stage and an analysis of the possible relationships among the variables under research. Results show that students have a moderately positive attitude towards the subject, where pleasure, appreciation and anxiety play a central role in its characterization.

El objetivo de mejorar el proceso de enseñanza y aprendizaje de los Métodos Numéricos en los estudiantes universitarios de las carreras de Matemática de la Facultad de Ciencias Exactas y Naturales de la Universidad Nacional de Mar del Plata (Argentina), nos llevó a indagar en las posibles causas que podrían influir negativamente en dicho proceso. Encontramos la necesidad de prestar atención a las actitudes, principalmente por considerar que éstas pueden tener una importante influencia sobre el rendimiento académico inmediato. El estudio comprendió una etapa de diseño, prueba piloto, validación del instrumento y análisis de las coherencias de las respuestas mediante la clasificación de conglomerados por variables, una etapa descriptiva y un análisis de las posibles relaciones entre las variables estudiadas. Los resultados muestran que los estudiantes tienen una actitud moderadamente positiva hacia la asignatura, donde el agrado, la valoración y la ansiedad juegan un papel fundamental.

O presente trabalho avalia a existência de tendências monotônicas em séries anuais e sazonais de vazão e chuva, no trecho da Bacia do Rio Paraibuna localizado entre os Núcleos Cunha e Santa Virgínia, Parque Estadual da Serra do Mar (SP). O teste de Mann-Kendall foi aplicado a séries destas variáveis, em diversos intervalos no período de 1967 a 2011. Tendências negativas estatisticamente significativas foram detectadas nas séries de chuva de longo prazo (a partir de 1967), anuais e sazonais, da estação 2344009, localizada na região de Cunha. Não foram detectadas tendências significativas nas séries das estações 2345067 (pluviométrica) e 58060000 (fluviométrica), localizadas no Núcleo Santa Virgínia.

This article assesses the existence of monotonic trends in streamflow and rainfall series, in the stretch of Paraibuna River Watershed located in the region of Santa Virgínia and Cunha Centers, Serra do Mar Range State Park (SP). The Mann-Kendall test was applied to annual and seasonal series of the mentioned variables, in several intervals during the period of 1967 to 2011. Statistically significant negative trends were detected only in the long-term (from 1967) rainfall series, both annual and seasonal, from station 2344009, located in the region of Cunha. No significant trends were detected in the series of stations 2345067 (rainfall) and 58060000 (streamflow), located in Santa Virginia Center.

Apresenta-se uma análise do conteúdo e a natureza das concepções sobre o ensino e a aprendizagem dos docentes universitários de ciências da Universidad Nacional de Mar del Plata, Argentina. Realizou-se um estudo descritivo das variáveis "concepções sobre a aprendizagem" e "índice de consistência", tomando como marco teórico as teorias implícitas, e utilizando um desenho ex-post-facto prospectivo. Para a coleta de dados se adaptou e validou um questionário de dilemas a partir do qual foram consultados 100 sujeitos. Os resultados mostram que os docentes possuem concepções nas que predomina a teoria construtiva da aprendizagem nos aspectos "o que é aprender" e "o que e como se aprende", enquanto que respeito do "que e como se avalia", prevalece a teoria interpretativa. Com respeito à natureza, os valores obtidos para o índice de consistência indicam que, embora as concepções dos docentes possam considerar-se consistentes, o nível achado não permite equiparar esta consistência com a que corresponderia a aquela com a que se adquire uma teoria científica.

This article presents an analysis of the nature and content of the conceptions of teaching and learning held by the science professors of the National University of Mar del Plata in Argentina. A descriptive study was performed on the variables "conceptions of teaching" and "consistency index", using the implied theories as a theoretical framework and a prospective ex-post-facto design. A dilemma questionnaire was adapted and validated for data collection purposes and administered to 100 subjects. The results show that professors have a predominantly constructivist conception of learning with regard to "what learning is" while with regard to "what and how they assess" the interpretive theory prevails. On the subject of nature, the values obtained for the consistency index show that although the conceptions of the professors can be considered as consistent, the discovered level does not allow to compare said consistency with the one in learning a scientific theory.

Se presenta un análisis del contenido y la naturaleza de las concepciones sobre la enseñanza y el aprendizaje de los docentes universitarios de ciencias de la Universidad Nacional de Mar del Plata, Argentina. Se realizó un estudio descriptivo de las variables "concepciones sobre el aprendizaje" e "índice de consistencia", tomando como marco teórico las teorías implícitas, y utilizando un diseño ex-post-facto prospectivo. Para la recolección de datos se adaptó y validó un cuestionario de dilemas a partir del cual fueron consultados 100 sujetos. Los resultados muestran que los docentes poseen concepciones en las que predomina la teoría constructiva del aprendizaje en los aspectos "qué es aprender" y "qué y cómo se aprende", mientras que respecto de "qué y cómo se evalúa", prevalece la teoría interpretativa. Con respecto a la naturaleza, los valores obtenidos para el índice de consistencia indican que, si bien las concepciones de los docentes pueden considerarse consistentes, el nivel encontrado no permite equiparar dicha consistencia con la que correspondería a aquella con la que se adquiere una teoría científica.

The manner in which the domain of training influences teachers' epistemological conceptions, has led to two major research lines: one assumes that conceptions about scientific knowledge are general and the other suggests that they are influenced by the nature of the discipline of training and by the degree and depth of that training. The aim of this paper is to analyze the influence of domain issues on the content of university teachers' personal epistemologies. A simple prospective design study was carried out. The sample, not random, consisted of one hundred college teachers of the Universidad Nacional de Mar del Plata, Argentina, trained in mathematics, chemistry, physics and biology. Two variables were analyzed in their possible associations: V1 Conceptions of scientific knowledge and V2: domain of training. To collect data it was used a dilemmas questionnaire, previously validated. The findings provide empirical evidence to the line of research that holds that the domain of training affects conceptions of scientific knowledge and that its influence is increased by academic experience.

El modo en que las cuestiones de dominio - entendido como disciplina de formación - influyen sobre las concepciones epistemológicas de los docentes, ha dado lugar a dos grandes líneas de investigación: la que supone que las concepciones sobre el conocimiento son generales y trascienden los dominios y la que sugiere que son influidas por la naturaleza de la disciplina de formación y por el grado y la profundidad de dicha formación. El objetivo de este trabajo es analizar la influencia que tienen las cuestiones de dominio sobre el contenido de las epistemologías personales de docentes universitarios de ciencias. Se realizó un estudio con un diseño ex post facto prospectivo simple. La muestra, no probabilística, estuvo compuesta por cien docentes universitarios formados en matemática, química, física y biología de la Universidad Nacional de Mar del Plata, Argentina. Se establecieron dos variables: V1: Concepciones sobre el conocimiento y V2: Dominio de Formación y se analizaron sus posibles asociaciones. El instrumento utilizado para recolectar datos fue un cuestionario de dilemas validado previamente. Los resultados obtenidos aportan evidencia empírica a la línea de investigación que sostiene que el dominio de formación influye en las concepciones sobre el conocimiento científico de los docentes y que su influencia es mayor a medida que aumenta la experiencia académica.

The academic yield achieved by sophomore students of the course Numerical Method attended by students of education and bachelors of mathematics of the University of Mar del Plata in Argentina has been studied. The traditional teaching method was compared with a new methodology that promotes participation of students and thatfavors cognitive independence. The results obtained by students working with the traditional method (11 students) were compared with those of the students that used the new method (13 students). The work shows that the new proposal increases the academic yield in this particular course.

En este trabajo se presenta el análisis del rendimiento académico alcanzado por los alumnos en la asignatura Métodos Numéricos perteneciente al segundo cuatrimestre del segundo año de las carreras de Profesorado y Licenciatura en Matemática de la Facultad de Ciencias Exactas y Naturales de la Universidad Nacional de Mar del Plata en Argentina. Se comparó el método tradicional de enseñanza con una nueva propuesta metodológica que favorece el aprendizaje constructivo y participativo, tendiente a la independencia cognoscitiva. Se comparó los resultados obtenidos por los alumnos que trabajaron con la nueva propuesta (13 alumnos) con los que continuaron con el dictado tradicional (11 alumnos). Se muestra que la nueva propuesta favorece el rendimiento académico en la asignatura.

Teachers and teaching students have different teaching and learning conceptions from those which are formally included in university courses. Instruction is always based on some conception of learning and a large part of learning is influenced by the ways that teachers perceive the course, the subject and the expectations about the learners. These predominant ideas are mostly implicit and different from the explicit conceptions. The objective of this article is to present the adaptation and validation of an instrument to investigate the conceptions about the knowledge that university teaching students have, and to make a first analysis of the results obtained from its application. A cross-sectional study was conducted at the UNMDP, Mar del Plata, Argentina. An instrument consisting in 12 items was adapted from the Dilemas Questionnary of Martin, Mateos, Pérez-Echeverría, Pozo, Pecharromán, Martínez and Villalón and applied to 120 students. Statistical analysis included Cronbach's Alpha for testing reliability and Factorial Analysis for testing construct validity. The first results show a predominance of the interpretative theory of learning, based on a realistic epistemological conception.

Tanto los profesores ya formados como los profesores en formación, poseen concepciones sobre el aprendizaje y la enseñanza que no corresponden con las teorías del aprendizaje que se estudian formalmente en los cursos universitarios. Las ideas que predominan en la construcción de estos marcos paradigmáticos, desde los cuales las personas entienden un escenario de acción, poseen un carácter más bien implícito y muchas veces difieren de las concepciones que explícitamente se manifiestan. El objetivo de este artículo es presentar la adaptación y validación de un instrumento para indagar las concepciones sobre el aprendizaje que poseen los profesores en formación avanzados de las Facultades de Humanidades y de Ciencias Exactas y Naturales de la Universidad Nacional de Mar de la Plata, Argentina, y hacer un primer análisis de los resultados obtenidos a partir de su aplicación. Esto se llevó a cabo mediante la adaptación de un cuestionario de dilemas elaborado por Martín, Mateos, Pérez-Echeverría, Pozo, Pecharromán, Martínez y Villalón administrado a 120 estudiantes. Para determinar la fiabilidad del análisis factorial y en consecuencia, la validez de constructo, se utilizó el Alpha de Cronbach. El posterior análisis de los datos muestra el uso de la teoría interpretativa del aprendizaje, basada en una concepción epistemológica vinculada con el realismo crítico.

Changes in vegetation communities of the eastern coastal plains of Buenos Aires Province during the Holocene were reconstructed based on the comparison of palynological records from two radiocarbon dated cores located north (T9-1, 36° 45' S; 56° 37' W) and south (La Lagunita, 37° 43' S; 57° 21' W) of Villa Gesell headland. Between 5,400 and 3,300 14C yr B.P. pollen records suggest the development of similar mosaics of halophytic-psammophytic communities at both sites, on tidal plains related to littoral barriers prograding simultaneously to the north and south of the Villa Gesell headland during the regressive event when sea level was stabilized. The Poaceae/Chenopodiaceae index (PCI) fluctuations suggest environmental instability as a consequence of barriers changes. From ca . 3,300 14C yr B.P. vegetation communities changed and differentiated at both sides of Villa Gesell headland simultaneously with the stabilization of the environments during the sea level regression, as it is reflected by a change in PCI with similar values and sign. To the north, at ca . 3,300 14C yr B.P. the mosaic of halophytic-psammophytic communities from environments associated to the barrier was replaced by a community placed on stabilized sand dunes associated with the advance toward the north of beach ridges of the barrier. To the south, at ca . 2,500 14C yr B.P. halophytic communities dominated by Chenopodiaceae were established reaching a higher development in a sheltered salt marsh and coastal lagoon environment, delimited by the rapid southwest progradation of the barrier.

Se reconstruyeron los cambios de las comunidades vegetales de las llanuras costeras del este de la provincia de Buenos Aires durante el Holoceno a partir de la comparación de registros palinológicos provenientes de dos testigos datados ubicados al norte (T9-1, 36° 45' S; 56° 37' O) y al sur (La Lagunita, 37° 43' S; 57° 21' O) de la Paleopunta Villa Gesell. Entre 5.400 y 3.300 14C años A.P. los registros palinológicos sugieren el desarrollo de mosaicos de comunidades halófitas-psammófitas semejantes en ambos sitios sobre llanuras de mareas relacionadas con la progradación simultánea de barreras litorales hacia el norte y hacia el sur de la Paleopunta Villa Gesell durante un periodo de estabilidad del nivel del mar durante el evento regresivo. Las fluctuaciones del índice Poaceae/Chenopodiaceae (IPC) evidencian la inestabilidad del ambiente como consecuencia de las modificaciones de las barreras. A partir de ca . 3.300 14C años A.P. las comunidades vegetales cambiaron y se diferenciaron a ambos lados de la Paleopunta Villa Gesell simultáneamente con la estabilización de los ambientes, reflejado por un cambio en el IPC con valores semejantes y del mismo signo. Al norte, ca . 3.300 14C años A.P. el mosaico de comunidades halófitas-psammófitas de ambientes asociados a la barrera fue reemplazado por una comunidad de médanos estabilizados asociados con el avance hacia el norte de las crestas de playa de la barrera. Al sur, ca . 2.500 14C años A.P. se establecieron comunidades halófitas dominadas por Chenopodiaceae, que alcanzaron su mayor desarrollo en una marisma protegida y un ambiente albuférico de laguna costera, delimitados por la rápida progradación de la barrera hacia el sur-oeste.