INFLUENCE OF CELL WALL CALCIUM CONTENT IN FRUIT FIRMNESS DURING THE RIPENING OF PLUMS (PRUNUS DOMESTICA L.).

‘Rainha Claudia Verde’ is a regional cultivar of Prunus domestica L. well adapted to a specific region in the south of Portugal. In order to understand the postharvest behavior of this cultivar produced in different orchards, cell wall poly-saccharides and cell wall calcium fruit content were studied during ripening in two consecutive years. During harvest period pectic fractions soluble in water, carbonate and KOH were prepared from alcohol-insoluble residue (AIR) of plums. Galacturonic and neutral sugars contents were measured during fruit ripening and fruit firmness was also evaluated. The calcium fruit level was determined in the AIR during harvest season as well as in dry matter. Fruit firmness was significantly higher in the second year and was probably related with calcium fruit content and pectic polysaccharides. There was a significant difference in calcium fruit content between orchards, and this might influence the overall fruit texture during the postharvest period. During fruit ripening water soluble pectic polysaccharides did not change significantly, which corresponded with the small decrease in tissue firmness. The occurrence in the supernatant of the cellulosic residue of highly branched polysaccharides might be the consequence of matrix material associated with microfibrilar phase. Depolymerization of the hemicellulosic fraction was not evident during plum ripening. The loss of fruit firmness is a consequence of many cellular events which are influenced by external factors. The knowledge of calcium content in the cell wall and the pectic poly¬saccharides could be of great importance to local farmers to predict fruit texture

Stellar population synthesis models between 2.5 and 5 {\mu}m based on the empirical IRTF stellar library

We present the first single-burst stellar population models in the infrared wavelength range between 2.5 and 5 {\mu}m which are exclusively based on empirical stellar spectra. Our models take as input 180 spectra from the stellar IRTF (Infrared Telescope Facility) library. Our final single-burst stellar population models are calculated based on two different sets of isochrones and various types of initial mass functions of different slopes, ages larger than 1 Gyr and metallicities between [Fe/H] = -0.70 and 0.26. They are made available online to the scientific community on the MILES web page. We analyse the behaviour of the Spitzer [3.6]-[4.5] colour calculated from our single stellar population models and find only slight dependences on both metallicity and age. When comparing to the colours of observed early-type galaxies, we find a good agreement for older, more massive galaxies that resemble a single-burst population. Younger, less massive and more metal-poor galaxies show redder colours with respect to our models. This mismatch can be explained by a more extended star formation history of these galaxies which includes a metal-poor or/and young population. Moreover, the colours derived from our models agree very well with most other models available in this wavelength range. We confirm that the mass-to-light ratio determined in the Spitzer [3.6] {\mu}m band changes much less as a function of both age and metallicity than in the optical bands.Comment: 25 pages, 19 figures, published in MNRAS, models can be downloaded from http://miles.iac.e

MILES extended: Stellar population synthesis models from the optical to the infrared

We present the first single-burst stellar population models which covers the optical and the infrared wavelength range between 3500 and 50000 Angstrom and which are exclusively based on empirical stellar spectra. To obtain these joint models, we combined the extended MILES models in the optical with our new infrared models that are based on the IRTF (Infrared Telescope Facility) library. The latter are available only for a limited range in terms of both age and metallicity. Our combined single-burst stellar population models were calculated for ages larger than 1 Gyr, for metallicities between [Fe/H] = -0.40 and 0.26, for initial mass functions of various types and slopes, and on the basis of two different sets of isochrones. They are available to the scientific community on the MILES web page. We checked the internal consistency of our models and compared their colour predictions to those of other models that are available in the literature. Optical and near infrared colours that are measured from our models are found to reproduce the colours well that were observed for various samples of early-type galaxies. Our models will enable a detailed analysis of the stellar populations of observed galaxies.Comment: 9 pages, 10 figures, published in A&

Single Stellar Populations in the Near-Infrared - I. Preparation of the IRTF spectral stellar library

We present a detailed study of the stars of the IRTF spectral library to understand its full extent and reliability for use with Stellar Population (SP) modeling. The library consist of 210 stars, with a total of 292 spectra, covering the wavelength range of 0.94 to 2.41 micron at a resolution R = 2000. For every star we infer the effective temperature (Teff), gravity (logg) and metallicity ([Z/Zsun]) using a full-spectrum fitting approach in a section of the K band (2.19 to 2.34 micron) and temperature-NIR colour relations. We test the flux calibration of these stars by calculating their integrated colours and comparing them with the Pickles library colour-temperature relations. We also investigate the NIR colours as a function of the calculated effective temperature and compared them in colour-colour diagrams with the Pickles library. This latter test shows a good broad-band flux calibration, important for the SP models. Finally, we measure the resolution R as a function of wavelength. We find that the resolution increases as a function of lambda from about 6 angstrom in J to 10 angstrom in the red part of the K-band. With these tests we establish that the IRTF library, the largest currently available general library of stars at intermediate resolution in the NIR, is an excellent candidate to be used in stellar population models. We present these models in the next paper of this series.Comment: 17 pages, 19 figures. Accepted for publication in Astronomy and Astrophysic

How can the land managers and his multi-stakeholder network at the farm level influence the multifunctional transitions pathways?

The changing role of agriculture is at the core of transition pathways in many rural areas. Productivism, post-productivism and multifunctionality have been targeted towards a possible conceptualization of the transition happening in rural areas. The factors of change, including productivist and post-productivist trends, are combined in various ways and have gone in quite diverse directions and intensities, in individual regions and localities. Even, in the same holding, productivist and post-productivist strategies can co-exist spatially, temporally, structurally, leading to a higher complexity in changing patterns. In south Portugal extensive landscapes, dominated by traditionally managed agro-forestry systems under a fuzzy land use pattern, multifunctionality at the farm level is indeed conducted by different stakeholders whose interests may or not converge: a multifunctional land management may indeed incorporate post-productivist and productivist agents. These stakeholders act under different levels of ownership, management and use, reflecting a particular land management dynamic, in which different interests may exist, from commercial production to a variety of other functions (hunting, bee-keeping, subsistence farming, etc.), influencing management at the farm level and its supposed transition trajectory. This multistakeholder dynamic is composed by the main land-manager (the one who takes the main decisions), sub land-managers (land-managers under the rules of the main land-manager), workers and users (locals or outsiders), whose interest and action within the holding may vary differently according to future (policy, market, etc.) trends, and therefore reflect more or less resilient systems. The goal of the proposed presentation is to describe the multi-stakeholder relations at the farm level, its spatial expression and the factors influencing the land management system resilience in face of the transition trends in place

Characterizing stellar populations in spiral disks

It is now possible to measure detailed spectral indices for stellar populations in spiral disks. We propose to interpret these data using evolutionary synthesis models computed from the Star Formation Histories obtained from chemical evolutionary models. We find that this technique is a powerful tool to discriminate between old and young stellar populations. We show an example of the power of Integral Field spectroscopy in unveiling the spatial distribution of populations in a barred galaxy.Comment: 5 pages, to be published in "Science Perspectives for 3D Spectroscopy", Eds. M. Kissler-Patig, M.M. Roth and J.R. Walsh (Springer-Verlag, ESO astrophysics symposia series

Towards real-time stereoscopic image rectification for 3D visualization

This paper describes a method for stereoscopic rectification with geometric distortion minimisation, to generate suitable image pairs for 3D viewing applications. The current state of the art technique is not optimal as it lacks appropriate mathematical constraints. We present a new approach that enforces the same distortion minimisation criterion with more computational e±ciency whilst also achieving superior distortion removal. Detailed mathematical expressions have been developed that fully constrain the system to facilitate the use of faster and more accurate non-linear optimisation algorithms. Appropriate rectification transforms can then be defined at speeds suitable for real-timeimplementation

Static quantities of a neutral bilepton in the 331 model with right-handed neutrinos

A neutral vector boson can possess static electromagnetic properties provided that the associated field is no self-conjugate. This possibility is explored in the $SU_C(3) X SU_L(3) X U_N(1)$ model with right-handed neutrinos, which predicts a complex neutral gauge boson $Y^0$ in a nontrivial representation of the electroweak group. In this model the only nonvanishing form factors are the CP-even ones, which arise from both the quark and gauge sectors, and contribute to the magnetic dipole and the electric quadrupole moments of this neutral particle.Comment: 10 pages, 6 figures, submitted to Phys. Rev.