The eta transition form factor from space- and time-like experimental data

The $\eta$ transition form factor is analysed for the first time in both space- and time-like regions at low and intermediate energies in a model-independent approach through the use of rational approximants. The $\eta\rightarrow e^+e^-\gamma$ experimental data provided by the A2 Collaboration in the very low energy region of the dilelectron invariant mass distribution allows for the extraction of the most precise up-to-date slope and curvature parameters of the form factors as well as their values at zero and infinity. The impact of these new results on the mixing parameters of the $\eta$-$\eta^\prime$ system, together with the role played by renormalisation dependent effects, and on the determination of the $VP\gamma$ couplings from $V\to P\gamma$ and $P\to V\gamma$ radiative decays are also discussed.Comment: 16 pages, 17 figures; v2: additional comments, references added; mathces published version in EPJ

Central pseudoscalar production in pp scattering and the gluon contribution to the proton spin

Central pseudoscalar production in $pp$ scattering is suppressed at small values of $Q_\perp$, where $Q$ is defined as the difference between the momenta transferred from the two protons. Such a behaviour is expected if the production occurs through the fusion of two vectors. Photon exchange could provide the dominant contribution at low transferred momenta, but we argue that an extension of the experiment could probe the gluon contribution to the proton spin.Comment: 12 pages, 2 figures and 3 tables, uses epsf.sty. Added references and tables. Minor changes include

Combined analysis of the decays τ−→KSπ−ντ\tau^-\to K_S\pi^-\nu_\tau and τ−→K−ηντ\tau^-\to K^-\eta\nu_\tau

In a combined study of the decay spectra of $\tau^-\to K_S\pi^-\nu_\tau$ and $\tau^-\to K^-\eta\nu_\tau$ decays within a dispersive representation of the required form factors, we illustrate how the $K^*(1410)$ resonance parameters, defined through the pole position in the complex plane, can be extracted with improved precision as compared to previous studies. While we obtain a substantial improvement in the mass, the uncertainty in the width is only slightly reduced, with the findings $M_{K^{*\prime}}=1304 \pm 17\,$MeV and $\Gamma_{K^{*\prime}} = 171 \pm 62\,$MeV. Further constraints on the width could result from updated analyses of the $K\pi$ and/or $K\eta$ spectra using the full Belle-I data sample. Prospects for Belle-II are also discussed. As the $K^-\pi^0$ vector form factor enters the description of the decay $\tau^-\to K^-\eta\nu_\tau$, we are in a position to investigate isospin violations in its parameters like the form factor slopes. In this respect also making available the spectrum of the transition $\tau^-\to K^-\pi^0\nu_\tau$ would be extremely useful, as it would allow to study those isospin violations with much higher precision.Comment: 20 pages, 1figur

The Contribution of Organic Livestock to Sustainable Rural Development in Sensitive Areas

Organic production may contribute positively to rural development. However, there is a gap of knowledge with regard to the livestock sector that the present work is aimed at filling by means of a multidisciplinary and participatory approach. The results suggest that ‘fully organic’ holdings (organic farms that sell products as organic) have the highest potential to contribute to the rural development in the area under study. Nevertheless, its implementation requires higher levels of education and implies higher costs. Due to these difficulties, public subsidies should support such production systems. Moreover, systems with low productivity but high environmental services should be also supported, such as those extensive (either conventional or organic)

Gross output and livestock sales modelling in Spanish extensive farms using PLSR

The aim of this paper is to model some production variables in extensive livestock farms located in the dehesa ecosystem. We intend to use not only purely economic variables in the construction of the model, but also structural variables in order to identify the characteristics of the farms that have the higher influence. Another objective is to be able to predict these variables at the farm level, using structural variables that are easy to measure. The data used in this work were obtained from a questionnaire survey to the holders/managers of a sample of 69 dehesa farms in Extremadura (SW Spain). The statistical methodology used for the construction of the model was Partial Least Square Regression (PLSR). It can be concluded that the variables relative to farm intensification, to labour and especially to Iberian pig breeding, are those that take part mainly in the model.dehesa, livestock farming systems, partial least square regression, gross output, Crop Production/Industries, Livestock Production/Industries, Research Methods/ Statistical Methods,

Sustainability of organic and conventional beef cattle farms in SW Spanish rangelands (‘dehesas’): a comparative study

Organic production in Spain has increased substantially in recent years due to several factors, such as the growing interest of the European Union towards preserving sensitive ecosystems; the potential role of organic production in the socio-economic development of rural areas and the growing consumers' demand for safer and higher quality foods. Within this framework, this paper analyzes the beef sector of SW Spanish rangelands (dehesas). These are traditional systems characteristic of the Iberian Peninsula where native herbaceous vegetation and evergreen species of Quercus provide the basis for extensive beef farms. Alt-hough traditional management in dehesa farms is of vital importance for the sustainability of this particular ecosystem, in the last years many farms have turned to organic production, trying to take advantage both of new subsidies and of new market trends.With this study, we try to evalu-ate the sustainability of conventional and organic beef production systems in dehesas in Extre-madura (SW Spain), trying to determine the level these systems are contributing both to the preservation of this sensitive ecosystem and to the socioeconomic development of the region. To this end, we apply a methodological adaptation of the MESMIS methodology to 90 dehesa beef farms located in Extremadura (SW Spain). MESMIS is based on the evaluation of basic attributes of sustainability that allow one to make a simultaneous and comparative analysis of different types of farms. It has been found that organic farms are the most sustainable, obtaining higher scores than con-ventional farms in stability and self-reliance, and similar scores in productivity, adaptability, and equity. Organic dehesa beef farms show little dependence on external products and services and are more adapted to their environment (lower stocking rates for an optimal use of the system's feedstuff production), those being the clues for their enhanced sustainability

Evaluación de la sostenibilidad de explotaciones caprinas extremeñas en áreas desfavorecidas como herramienta de apoyo en la conversión hacia explotaciones ecológicas.

INTRODUCTION: The Ibores-Villuercas region (located in SW Spain) is known for its dairy goat farms producing cheeses of high quality (P.D.O. Queso Ibores). The present study characterizes such farms and assess their sustainability, as a tool to determine which farms present more feasibility to carry out a conversion to the organic system. This conversion could be used as a marketing tool for these farms, and contribute to local development (both economically and socially), ensuring the maintenance of the farms and rural population while enabling the preservation of valuable landscapes. METHODOLOGY: farms where classified using cluster analysis. Later, a sustainability assessment of the clusters (groups of farms) was carried out. Finally, farms' difficulties and advantages producing under the organic model where predicted. RESULTS and DISCUSSION: 3 groups of farms were obtained. Group 1 farms were intensive ones, using highly-productive dairy breeds fed high proportion of concentrates. Group 2 were semi-extensive of higher surface and mixed with sheeps, where autochthonous and allochthonous races are reared, and management is closer to a traditional one. Finally, group 3 was a traditional one, closer to the orgnaic management, with low stocking rates and native breeds feeding local feed resources. Regarding the attributes of sustainability, group 3 showed advantages in terms of self-management, which is important under the organic system and areas of scarcity of feed resources (such as that studied)

Conversión de sistemas de producción caprinos de áreas desfavorecidas a ganadería ecológica

INTRODUCTION: The Spanish goat sector's crisis has led to the abandonment of a large number of farms. At present, sector's expectations are reduced, which threatens farms' permanence. This in turn means a loss of agricultural biodiversity, reduced economic activity and loss of rural population. In this context, it is necessary to implement strategies to ensure farms' continuity . In this sense, the conversion to the organic model is proposed in the farms analyzed. METHODOLOGY: To study the possibility and feasibility of such conversion an analysis of their structure (technical and economic characteristics), an assessment of farms' sustainability (based on social, economic and environmental parameters) has been carried out. For this purpose, the MESMIS Framework was used