The aim of this study was to quantify the water consumption and the crop coefficients (Kc) for the potato (Solanum tuberosum L.), in Seropédica, Rio de Janeiro (RJ), Brazil, under organic management, and to simulate the crop evapotranspiration (ETc) using the Kc obtained in the field and the ones recommended by the Food and Agriculture Organization (FAO). The water consumption was obtained through soil water balance, using TDR probes installed at 0.15m and 0.30m deep. At the different stages of development, the Kc was determined by the ratio of ETc and reference evapotranspiration, obtained by Penman-Monteith FAO 56. The crop coefficients obtained were 0.35, 0.45, 1.29 and 0.63. The accumulated ETc obtained in the field was 109.6 mm, while the ETc accumulated from FAO's Kc were 142.2 and 138mm, respectively, considering the classical values and the values adjusted to the local climatic conditions. The simulation of water consumption based on meteorological data of historical series from 1961 to 2007 provided higher value of ETc when compared with the one obtained in the field. From the meteorological data of historical series, it was observed that the use of Kc recommended by FAO may overestimate the amount of irrigation water by 9%, over the same growing season.
O trabalho foi desenvolvido visando a quantificar, sob manejo agroecológico, o consumo hídrico e os kcs para a cultura da batata (Solanum tuberosum L.), em Seropédica (RJ), e a simular a evapotranspiração da cultura (ETc), utilizando os kcs obtidos e os kcs preconizados pela FAO. O consumo hídrico foi obtido por meio do balanço hídrico do solo, utilizando sondas de TDR instaladas a 0,15 e 0,30 m de profundidade. Nas diferentes fases de desenvolvimento, o kc foi determinado pela razão entre a ETc e a evapotranspiração de referência, obtida por Penman-Monteith FAO 56. Os kcs obtidos foram 0,35; 0,45; 1,29 e 0,63. A ETc acumulada obtida em campo foi de 109,6 mm, enquanto as ETcs acumuladas a partir dos kcs FAO foram de 142,2 e 138,0 mm, respectivamente, considerando os valores clássicos e os corrigidos para as condições climáticas locais. A simulação do consumo hídrico com base nos dados meteorológicos da série histórica de 1961 a 2007 proporcionou valor maior de ETc quando comparado ao obtido em campo. A partir dos dados meteorológicos obtidos na série histórica, observou-se que a utilização de kcs preconizados pela FAO pode superestimar a quantidade de água na irrigação em 9%, considerando o mesmo período de cultivo.
In this work we use the IGM, a model that describes well the energy flux in hadronic collisions, to study the leading particle spectrum when saturation effects on the gluon distribution function are included. The leading particle spectrum is calculated for several center of mass energies (<FONT FACE=Symbol>Ö</FONT>s). In the very high energy limit we compare our results with the predictions made in a recent paper, which also addresses the same problem.
The Interacting Gluon Model (IGM) is a tool designed to study energy flow, especially stopping and leading particle spectra, in high energy hadronic collisions. In this model, valence quarks fly through and the gluon clouds of the hadrons interact strongly both in the soft and in the semihard regime. Developing this picture we arrive at a simple description of energy loss, given in terms of few parameters, which accounts for a wide variety of experimental data. This text is a survey of our main results and predictions.
Recent DESY-HERA data on J/<FONT FACE="Symbol">Y</font> elasticity distribution show that it emerges mostly as a fast particle. Interpreting photoproduction as a collision between a pre-formed charmed hadron and the proton, the outcoming J/<FONT FACE="Symbol">Y</font> is a leading particle of the collision. We analyse these data using a model formulated to describe energy flow in hadron-hadron reactions. The measured J/<FONT FACE="Symbol">Y</font> spectrum can be successfully described in terms of this model. We conclude that the observed transparency of the charmed hadron-proton collisions arises because of the particularly small gluonic content of the initial c - <img src="http:/img/fbpe/bjp/v28n4/image200.gif" alt="Image200.gif (847 bytes)" align="absbottom"> state.