RESPONSE OF STRAWBERRY PLANTS TO SHORTENING DAY LENGTH , SHADING AND COLD STORAGE UNDER EGYPTIAN CONDITIONS

This experiment was performed in 2004/2005 and 2005/2006 seasons at El-Bosaly Protected Cultivation Experimental Site, of the Central Laboratory for Agricultural Climate (CLAC), 15 Km west of Rosetta. The current study was conducted in open field to investigate the growth and productivity of strawberry plants under the shading and cold storage methods. Two strawberry cultivars were used, i.e., Camarosa (cv.) and Yael (cv.). Transplants were set up on 15 of March to 15 of September in both two seasons of 2004-2005 and 2005-2006, respectively under El-Bosaly conditions. Seven treatments were used i.e., short day, 40% shading, 73% shading, three periods cold storage at 5Co, i.e., (24h, 48h and 73h) and control. Results indicated that the application of 73% shading treatment was the most effective in reducing maximum and minimum of air temperature and radiation, followed by 40% shading, whereas, the highest value of maximum and minimum air temperature, radiation were observed in control treatment throughout the two growing seasons. In addition, 73% shading treatment produced the tallest plants and the highest number of leaves per plant and leaf area per plant. Moreover, flowering and chlorophyll in leaves were increased by application of short day treatment. Also, fruit characters such as average weight and number of fruits per plant were the highest values with 40% shading. Chemical components of fruits, i.e., T.S.S were increased with 73% shading treatment. When plants were grown under 40% shading treatment, followed by 73% shading, while cold storage for 72 h treatment gave the lowest values. Neither cultivars nor the interaction between cultivars and tested factors had any significant effects on many studied characters

Biases in the determination of dynamical parameters of star clusters: today and in the Gaia era

The structural and dynamical properties of star clusters are generally derived by means of the comparison between steady-state analytic models and the available observables. With the aim of studying the biases of this approach, we fitted different analytic models to simulated observations obtained from a suite of direct N-body simulations of star clusters in different stages of their evolution and under different levels of tidal stress to derive mass, mass function and degree of anisotropy. We find that masses can be under/over-estimated up to 50% depending on the degree of relaxation reached by the cluster, the available range of observed masses and distances of radial velocity measures from the cluster center and the strength of the tidal field. The mass function slope appears to be better constrainable and less sensitive to model inadequacies unless strongly dynamically evolved clusters and a non-optimal location of the measured luminosity function are considered. The degree and the characteristics of the anisotropy developed in the N-body simulations are not adequately reproduced by popular analytic models and can be detected only if accurate proper motions are available. We show how to reduce the uncertainties in the mass, mass-function and anisotropy estimation and provide predictions for the improvements expected when Gaia proper motions will be available in the near future.Comment: 14 pages, 8 figures, accepted for publication by MNRA

Modelling Molecular Motors as Folding-Unfolding Cycles

We propose a model for motor proteins based on a hierarchical Hamiltonian that we have previously introduced to describe protein folding. The proposed motor model has high efficiency and is consistent with a linear load-velocity response. The main improvement with respect to previous models is that this description suggests a connection between folding and function of allosteric proteins.Comment: 5 pages RevTeX, 2 Postscript figures, replaced due to LaTeX proble

Homogeneous photometry VII. Globular clusters in the Gaia era

We present wide-field, ground-based Johnson-Cousins UBVRI photometry for 48 Galactic globular clusters based on almost 90000 public and proprietary images. The photometry is calibrated with the latest transformations obtained in the framework of our secondary standard project, with typical internal and external uncertainties of order a few millimagnitudes. These data provide a bridge between existing small-area, high-precision HST photometry and all sky-catalogues from large surveys like Gaia, SDSS, or LSST. For many clusters, we present the first publicly available photometry in some of the five bands (typically U and R). We illustrate the scientific potential of the photometry with examples of surface density and brightness profiles and of colour-magnitude diagrams, with the following highlights: (i) we study the morphology of NGC 5904, finding a varying ellipticity and position angle as a function of radial distance; (ii) we show U-based colour-magnitude diagrams and demonstrate that no cluster in our sample is free from multiple stellar populations, with the possible exception of a few clusters with high and differential reddening or field contamination, for which more sophisticated investigations are required. This is true even for NGC 5694 and Terzan 8, that were previously considered as (mostly) single-population candidates.Comment: 24 pages, 12 figures, accepted for publication by MNRA

On the density profile of the globular cluster M92

We present new number density and surface brightness profiles for the globular cluster M92 (NGC 6341). These profiles are calculated from optical images collected with the CCD mosaic camera MegaCam at the Canada-France-Hawaii-Telescope and with the Advanced Camera for Surveys on the Hubble Space Telescope. The ground-based data were supplemented with the Sloan Digital Sky Survey photometric catalog. Special care was taken to discriminate candidate cluster stars from field stars and to subtract the background contamination from both profiles. By examining the contour levels of the number density, we found that the stellar distribution becomes clumpy at radial distances larger than about 13 arcminutes, and there is no preferred orientation of contours in space. We performed detailed fits of King and Wilson models to the observed profiles. The best-fit models underestimate the number density inside the core radius. Wilson models better represent the observations, in particular in the outermost cluster regions: the good global agreement of these models with the observations suggests that there is no need to introduce an extra-tidal halo to explain the radial distribution of stars at large radial distances. The best-fit models for the number density and the surface brightness profiles are different, even though they are based on the same observations. Additional tests support the evidence that this fact reflects the difference in the radial distribution of the stellar tracers that determine the observed profiles (main sequence stars for the number density, bright evolved stars for the surface brightness).Comment: 18 pages, 10 figures, Accepted by A