Management arrangements for accommodating nonrice crops in rice-based irrigation systems: Proceedings of the First Progress Review and Coordination Workshop of the Research Network on Irrigation Management for Crop Diversification in Rice-Based Systems (IMCD), held in Quezon City, the Philippines, 10-14 December 1990

Irrigation management / Crops / Diversification / Rice / Irrigated farming / Policy / Research / Sri Lanka / Bangladesh / India / Indonesia / Malaysia / Nepal / Philippines / Thailand

Collapse of Primordial Clouds

We present here studies of collapse of purely baryonic Population III objects with masses ranging from $10M_\odot$ to $10^6M_\odot$. A spherical Lagrangian hydrodynamic code has been written to study the formation and evolution of the primordial clouds, from the beginning of the recombination era ($z_{rec} \sim 1500$) until the redshift when the collapse occurs. All the relevant processes are included in the calculations, as well as, the expansion of the Universe. As initial condition we take different values for the Hubble constant and for the baryonic density parameter (considering however a purely baryonic Universe), as well as different density perturbation spectra, in order to see their influence on the behavior of the Population III objects evolution. We find, for example, that the first mass that collapses is $8.5\times10^4M_\odot$ for $h=1$, $\Omega=0.1$ and $\delta_i={\delta\rho / \rho}=(M / M_o)^{-1/3}(1+z_{rec})^{-1}$ with the mass scale $M_o=10^{15}M_\odot$. For $M_o=4\times10^{17}M_\odot$ we obtain $4.4\times10^{4}M_\odot$ for the first mass that collapses. The cooling-heating and photon drag processes have a key role in the collapse of the clouds and in their thermal history. Our results show, for example, that when we disregard the Compton cooling-heating, the collapse of the objects with masses $>8.5\times10^4M_\odot$ occurs earlier. On the other hand, disregarding the photon drag process, the collapse occurs at a higher redshift.Comment: 10 pages, MN plain TeX macros v1.6 file, 9 PS figures. Also available at http://www.iagusp.usp.br/~oswaldo (click "OPTIONS" and then "ARTICLES"). MNRAS in pres

Collapse of Primordial Clouds II. The Role of Dark Matter

In this article we extend the study performed in our previous article on the collapse of primordial objects. We here analyze the behavior of the physical parameters for clouds ranging from $10^7M_\odot$ to $10^{15}M_\odot$. We studied the dynamical evolution of these clouds in two ways: purely baryonic clouds and clouds with non-baryonic dark matter included. We start the calculations at the beginning of the recombination era, following the evolution of the structure until the collapse (that we defined as the time when the density contrast of the baryonic matter is greater than $10^4$). We analyze the behavior of the several physical parameters of the clouds (as, e.g., the density contrast and the velocities of the baryonic matter and the dark matter) as a function of time and radial position in the cloud. In this study all physical processes that are relevant to the dynamical evolution of the primordial clouds, as for example photon-drag (due to the cosmic background radiation), hydrogen molecular production, besides the expansion of the Universe, are included in the calculations. In particular we find that the clouds, with dark matter, collapse at higher redshift when we compare the results with the purely baryonic models. As a general result we find that the distribution of the non-baryonic dark matter is more concentrated than the baryonic one. It is important to stress that we do not take into account the putative virialization of the non-baryonic dark matter, we just follow the time and spatial evolution of the cloud solving its hydrodynamical equations. We studied also the role of the cooling-heating processes in the purely baryonic clouds.Comment: 8 pages, MN plain TeX macros v1.6 file, 13 PS figures. Also available at http://www.iagusp.usp.br/~oswaldo (click "OPTIONS" and then "ARTICLES"). MNRAS in pres

Vector meson quasinormal modes in a finite-temperature AdS/QCD model

We study the spectrum of vector mesons in a finite temperature plasma. The plasma is holographically described by a black hole AdS/QCD model. We compute the boundary retarded Green's function using AdS/CFT prescriptions. The corresponding thermal spectral functions show quasiparticle peaks at low temperatures. Then we calculate the quasinormal modes of vector mesons in the soft-wall black hole geometry and analyse their temperature and momentum dependences.Comment: 27 pages, 9 figure

Communication in organizations and 360-degree evaluation: what is the relationship between the two concepts?

The performance appraisal has a very important role in the strategic objectives of the organization, because it contributes to its efficacy (Aguinis, 2007). However, some limitations of top-down performance appraisal like the subjectivity have been proposed other evaluations, like 360-degree evaluation (Kondrasuk, 2012). This is a specific evaluation that considers more than one appraiser (Brutus & Gorriti, 2005). The purpose of this research is to know if the application of 360-degree evaluation influences organizational communication. We conducted a qualitative exploratory study through the interviews with experts. The results that will be presented are still preliminary and have theoretical and practical applications. In general, we conclude that 360-degree evaluation could be advantageous for organizational communication (e.g. active voice of employees; symmetrical and bi-directional communication).info:eu-repo/semantics/publishedVersio

Magnetostatics and the rotational sense of cycloidal spin spirals

The magnetostatic energy of a cycloidal spin-spiral configuration is calculated. The free-standing spiral is compared to the case of spirals that are brought in contact to a magnetically polarizable substrate. While a free-standing layer is energetically degenerate with respect to the spiral's sense of rotation, it is shown that a polarizable substrate breaks this symmetry and lifts the degeneracy. Consequently, a strongly polarizable substrate can stabilize (destabilize) a spin spiral that would be unstable (stable) without considering the magnetostatics of the substrateFunding by CONSOLIDER-INGENIO EN NANOCIENCIA MOLECULAR (ref. CSD2007 − 00010), by the Comunidad de Madrid through Project No. S2009/MAT-1726, and the Deutsche Forschungsgemeinschaft in the framework of SFB 668 is acknowledge