Use of consumer-grade cameras to assess wheat N status and grain yield

Relationships between (a) fractional Intercepted PAR (fIPAR), and (b) aboveground biomass (Biomass) and (c) grain yield at harvest with the Normalized Difference Vegetation Index (NDVI) derived either from a spectroradiometer or a conventional camera at final grain filling (n = 12).Postprint (published version

Population dynamics of Meloidogyne incognita on cucumber grafted onto the Cucurbita hybrid RS841 or ungrafted and yield losses under protected cultivation

The influence of the squash hybrid RS841 rootstock (Cucurbita maxima x C. moschata) on population dynamics of Meloidogyne incognita and yield of cucumber cv. Dasher II was assessed during 2013 and 2014 in a plastic greenhouse. In addition, the relationship between ecophysiological parameters (plant water status, gas exchange, and leaf reflectance) and Pi and cucumber yield were also estimated in 2013. Nematode densities were determined at the beginning (Pi) and at the end (Pf) of each crop, and the relationship between these parameters was used to estimate the maximum multiplication rate (a), the maximum population density (M) and the equilibrium density (E) per grafted and ungrafted cucumber and cropping season. Moreover, the relationship between the multiplication rate (Pf/Pi) and Pi was compared between grafted and ungrafted cucumber per cropping season. Finally, the relative yield of grafted or ungrafted cucumber was plotted against Pi to determine the tolerance limit (T) and the minimum relative yield (m) by the Seinhorst damage function model. Values of a, M and E in grafted cucumber were higher than in ungrafted one irrespective of the cropping season. These results were supported by comparing the relationship between Pf/Pi and Pi between grafted and ungrafted cucumber. The relationship between Pi and yield fitted the Seinhorst damage function. The values of T and m did not differ between grafted and ungrafted each year. Predawn water potential, net photosynthetic rate, and leaf chlorophyll index decreased with increasing Pi. In addition, relative yield was related to variation in net photosynthetic rate and the leaf chlorophyll index. Under the conditions of this study, RS841 rootstock was neither resistant nor tolerant to M. incognita.Postprint (published version

Currency Hedging Strategies Using Dynamic Multivariate GARCH

This paper examines the effect on the effectiveness of using futures contracts as hedging instruments of: 1) the model of volatility used to estimate conditional variances and covariances, 2) the analyzed currency, and 3) the maturity of the futures contract being used. For this purpose, daily data of futures and spot exchange rates of three currencies, Euro, British pound and Japanese yen, against the American dollar are used to analyze hedge ratios and hedging effectiveness resulting from using two different maturity currency contracts, near-month and next-to-near-month contract. We estimate four multivariate volatility models (CCC, VARMA-AGARCH, DCC and BEKK) and calculate optimal portfolio weights and optimal hedge ratios to identify appropriate currency hedging strategies. Hedging effectiveness index suggests that the best results in terms of reducing the variance of the portfolio are for the USD/GBP exchange rate. The results show that futures hedging strategies are slightly more effective when the near-month future contract is used for the USD/GBP and USD/JPY currencies. Moreover, CCC and AGARCH models provide similar hedging effectiveness although some differences appear when the DCC and BEKK models are used.Multivariate GARCH, conditional correlations, exchange rates, optimal hedge ratio, optimal portfolio weights, hedging strategies.

Water availability affects the capability of reflectance indices to estimate berry yield and quality attributes in rain-fed vineyards

Remote sensing methods are known to provide estimates of berry quality. However, previous studies have shown that the Normalized Difference Vegetation Index (NDVI) failed to predict berry quality attributes in rain-fed vineyards. This study explores the association of several reflectance indices with vine biophysical characteristics and berry yield and quality attributes and their temporal stability. The study was conducted in rain-fed Chardonnay vineyards located around Masquefa (Penedès region, Catalonia, Spain) over four years. Canopy reflectance, fractional Intercepted Photosynthetic Active Radiation, predawn water potential and canopy temperature at midday were measured at veraison whereas berry yield and quality attributes were determined at harvest. Water availability and vine biophysical attributes showed large temporal stability whereas berry quality attributes were not temporally stable. The capability of reflectance indices to estimate berry quality attributes was subject to the timing and extent of water deficits. The NDVI, the Photochemical Reflectance Index (PRI) and the Water Index (WI) provided estimates of berry quality attributes under mild, moderate and severe water deficits, respectively. These results might have potential applications in precision viticulture activities such as selective harvesting according to grape quality attributes and the assessment of ripening.Postprint (published version

Educative evaluation of nutrition policy at schools

El presente trabajo responde a la necesidad de repensar las actuales políticas y acciones dirigidas a la promoción de la salud desde una perspectiva antropológica, especialmente aquellas que atienden a la educación de la alimentación. En concreto, se analizarán las políticas nutricionales, a través de las medidas dirigidas a mejorar la alimentación de la población en los centros escolares, desde un enfoque educativo. Este enfoque consiste, en primer lugar, en valorar diferentes concepciones de la educación alimentaria y definir lo que entendemos nosotros desde una perspectiva integral. De esta definición se extraerán los indicadores que permitirán valorar las 38 acciones, derivadas de las políticas alimentarias y dirigidas a la educación alimentaria en el panorama internacional y nacional, encontradas en una revisión bibliográfica. Siguiendo esta metodología, observamos que la educación alimentaria se organiza en torno a cuatro ejes: su finalidad (cultura, salud, consumo y relación con el medio); su influencia (biológica y social); su organización (estructuralista y desarrollista) y su alcance (individual y comunitario). Por otro lado, en el análisis de medidas se destaca la heterogeneidad existente en cuanto a la finalidad de los programas, la alta prevalencia de programas justificados por el aumento y presencia de patologías derivadas de la alimentación, el enfoque comunitario de las medidas y la deficiencia de inclusión de la educación general en los programas de educación alimentaria. Como conclusión, es necesario profundizar en la comprensión de la alimentación como hecho humano y social, así como en los agentes responsables de la construcción del conocimiento en torno a este hecho. El enfoque educativo, en el diseño de políticas nutricionales y alimentarias es clave para el desarrollo social.This research responds to the need to integrate the theory of education in the design of policies and actions aimed at health promotion. Specifically, nutritional policies will be analyzed, through measures aimed at improving the diet of the population through schools, from an educational approach. This approach consists of defining, first of all, what is meant by education in the food field. From this definition, the indicators that will allow evaluating the 38 actions derived from food policies and aimed at food education, found in a bibliographic review. Following this methodology, we observe that food education is organized around four axes: its purpose (culture, health, consumption or relationship with the environment); its influence (biological or social); its organization (structuralist or developmental), and its kind of relation with education (individual or community).On the other hand, the analysis of measures highlights the existing heterogeneity regarding the purpose of the programs, the high prevalence of programs justified by the increase and presence of pathologies derived from food, the community approach to measures, and deficiency of inclusion of general education in food education programs. In conclusion, it is necessary to deepen the understanding of food as a human and social fact, as well as the agents responsible for the construction of its knowledge. The educational approach in the design of nutritional and food policies is key to social development.Fac. de EducaciónTRUEpu

The use of jclic in the english teaching-learning process

This Master Thesis presents the results of a research project carried out at the Primary School (C.E.I.P) Ferrer Guardia in Almeria with 5th grade class A and 5th grade class B students in order to verify if there is an impact of JClic at this school. The present paper proposes a mainly investigative objective; which is to demonstrate that the JClic programme can be an educational resource designed to improve the children’s abilities and skills so as to develop the Teaching-Learning process in the English classroom. Starting from a theoretical basis exploration in order to place and define the research aim, the different necessary stages of this research will be described, explaining and justifying at the same time the methodology and data used. In the end, the obtained results and conclusions will be analysed with the objective to establish possible improvement proposals for the JClic programme as an educational resource

Use of reflectance indices to assess vinewater status under mild to moderate water deficits

The monitoring of vine water status is of interest for irrigation management in order toimprove water use while optimizing both berry yield and quality. Remote-sensing techniques mightprovide accurate, rapid, and non-destructive estimates of vine water statusPeer ReviewedPostprint (published version

Currency hedging strategies, strategic benchmarks and the Global and Euro Sovereign financial crises

This paper investigates dynamic currency hedging benefits, with a further focus on the impact of currency hedging before and during the recent financial crises originated from the subprime and the Euro sovereign bonds. We take the point of view of a Euro-based institutional investor who considers passive investment strategies in portfolios holding European, British and US assets. We analyze the impact of the model specification to improve the risk-return tradeoff when currency risk is hedged. Hedging strategies of currency risk, using exchange rates futures and driven by several multivariate GARCH models, depend on the portfolio composition and period analyzed. Dynamic covariance models provide limited evidences of a decrease in hedging rations compared to naïve hedging strategies based on linear regressions or variance smoothing. Nevertheless, those results are coupled with better performances of dynamic covariance models in terms of hedging effectiveness an improved Sharpe ratios. The empirical evidences are observed both in-sample as well as in an out-of-sample exercise