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Search Results: 1 - 10 of 191801 matches for " Nava D "
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Marketing channels for wild and cultivated edible mushrooms in developing countries: the case of Mexico
D. Martínez Carrera,D. Nava,M. Sobal,M. Bonilla
Micología Aplicada Internacional , 2005,
Abstract: Food products require efficient marketing systems to move from producers to consumers keeping high quality and price. In many developing countries, although mushroom production is well established and increasing, the marketing systems are poorly understood. During 1999-2004, we studied the channels of distribution for wild and cultivated mushrooms in central Mexico following an institutional approach (550 interviews). Most wild and cultivated mushrooms are marketed within this region. Representative places were selected for this study: a large city (Mexico), two medium cities (Puebla, Toluca), and a rural community (Cuetzalan). Several marketing channels were identified and described, involving middlemen, wholesalers, retailers, tianguis , public markets, retail food stores, and food services. The grower s share, the gatherer s share, and the mushroom marketing margin were also estimated. The present mushroom marketing system evolved from a small centralized process to a combination of centralized and decentralized marketing processes involving limited activities. During this series of changes, large private enterprises took over several marketing functions supporting the decentralization process, but discouraging the development of new firms specialized in mushroom marketing and processing. At the same time, changes also led to the market concentration of open-market sales in large private enterprises and functional wholesalers. Main structure, organization and trends of the Mexican mushroom marketing system are discussed.
Efecto de fuentes y dosis de nitrógeno sobre la producción y calidad del fruto del banano (Musa grupo AAA subgrupo Cavendish clon "Gran Enano") en la Planicie Aluvial del Río Motatán
Finol,J; Fernández,L; Nava,C; Esparza,D;
Revista de la Facultad de Agronomía , 2004,
Abstract: effect of sources and dose of nitrogen on the production and quality of the fruit of the banana tree (musa group aaa, subgroup cavendish "gran enano" clon) in the alluvial plain of the motatán river
Efecto de fuentes y dosis de nitrógeno sobre la producción y calidad del fruto del banano (Musa grupo AAA subgrupo Cavendish clon "Gran Enano") en la Planicie Aluvial del Río Motatán
J Finol,L Fernández,C Nava,D Esparza
Revista de la Facultad de Agronomía , 2004,
Abstract: Con la finalidad de evaluar el efecto de tres fuentes de nitrógeno (Urea 46 %, N, Sulfato de Amonio 21% N y Nitrato de Amonio 32% N), dos dosis de aplicación (150 y 300 kg N/ha/a o), y un testigo de 0 kg N/ha/a o, en tres ciclos de aplicación sobre la producción y la calidad del banano, en un suelo Typic Ustropept, durante tres generaciones (plantas madres, hijas y nietas). La dosis de nitrógeno se fraccionó en seis porciones por a o (aplicaciones bimensuales). Se utilizó un dise o experimental de Bloques al Azar con un arreglo factorial 3 x 2 + 1 con 5 repeticiones. Previo a la aplicación de los tratamientos, se evaluaron los contenidos de nitrógeno del suelo y foliar. Se evaluó el rendimiento y calidad a través del peso del racimo, largo de los dedos centrales de la segunda y última mano, diámetro de los dedos centrales de la segunda mano, el ratio y el número de manos por racimo. Los resultados obtenidos a través del análisis de la varianza y las pruebas de medias indican que no hubo efectos significativos para fuente, dosis ni la interacción de estos para las diferentes variables medidas, se encontró efecto significativo para generación. Los mayores valores fueron obtenidos por la tercera generación, siendo estos: peso del racimo 45,5 kg ratio 2,8, dedos por mano 24, dedos por racimo 229,53, manos por racimo 11,94 cm, diámetro de los dedos centrales de la segunda mano 45,88 grados y largo (cm) de los dedos centrales de la segunda y última mano 28,46 y 29,71. Effect of sources and dose of nitrogen on the production and quality of the fruit of the banana tree (Musa group AAA, subgroup Cavendish "Gran Enano" clon) in the alluvial plain of the Motatán River
Evaluación de la colocación del fertilizante en la planta madre una vez cosechada sobre las variables de crecimiento y producción en el cultivo del plátano Harton (Musa AAB) Evaluation of fertilizer location in the Horn plantain (Musa AAB) mother′s pseudostem after harvesting on growth and production variables
M Labarca,L Sosa,D Esparza,C Nava
Revista de la Facultad de Agronomía , 2005,
Abstract: En los a os 1998 al 2000, en el municipio Francisco Javier Pulgar (Bosque Húmedo Tropical) del estado Zulia Venezuela, se evaluó el efecto de la forma de colocación del fertilizante utilizando el seudotallo de la planta madre cosechada (tocón), comparándola con la colocación del fertilizante en el suelo. Se usaron tres tipos de fertilizantes (urea, cloruro de potasio, y la mezcla de ambos) a tres niveles de altura, dos en el tocón a 0,75 y 1,00 m de altura y una al suelo, más el tratamiento utilizado en la finca, generando 10 tratamientos. El dise o estadístico fue un arreglo factorial 32+1 en bloques completos al azar con cuatro repeticiones. Los valores más altos, tanto para las variables de crecimiento, producción, así como para el índice Económico Relativo (IER), fueron los obtenidos con la aplicación de la mezcla de 150 g de cloruro de potasio más 150 g de urea en el tocón a 0,75 m de altura (T7), así para la variable de producción Peso del Racimo (PR), el máximo valor fue 15,23 kg similar a los valores obtenidos con la aplicación de la mezcla a 1m de altura en el tocón (T8) y a la aplicación de 150 g de cloruro de potasio en el tocón a 0,75 m de altura (T4). Igualmente este tratamiento provocó el mayor valor de IER (2.185,22 Bs planta-1), lo cual conduce a recomendar el uso de esta técnica, ya que a través de la misma puede lograrse una mayor eficiencia en el uso del fertilizante. In order to compare the fertilizer location form through the mother's pseudostem after harvesting with soil fertilizer application, from 1998 to 2000 an experiment was carried out in Francisco Javier Pulgar municipality, Zulia state. To this effect were used three kinds of fertilizers (urea, potassium chloride and urea-potassium chloride combination), placed at three height levels, two in the mother plant after harvesting (at 0.75 m and at 1 m tall) and another on the soil. An additional treatment was included; it was based on the farm's fertilization. The statistical design was a 32+1 factorial arrangement in randomized blocks with four replications and ten treatments. The highest values, both for the growing, production as well as for the relative economic index (REI), were obtained with the application of urea-potassium chloride combination in the mother's pseudostem at 0.75 m tall (T7). For the production variable bunch weight, the maximum value was 15.23 kg similar to the values obtained with the application of the combination at 1 m tall in the mother's pseudostem (T8) and the application of 150 gr of potassium chloride in the mother's pseudostem at 0.75 m tall (T4
Papillomatosis in water buffaloes (Bubalus bubalis)
O. Silvestre,D. Nava,G. Iovane,V. Russo
Italian Journal of Animal Science , 2010, DOI: 10.4081/ijas.2007.s2.888
Abstract: Cutaneous papillomatosis are common in the horse and in cattle and uncommon in other species. A large number of different papillomaviruses have been identified and each specie may be infected by different genotype. The authors describe the histopathological and electron microscopical findings of cutaneous papillomatosis in water buffaloes (Bubalus bubalis).
Exact ground state Monte Carlo method for Bosons without importance sampling
M. Rossi,M. Nava,L. Reatto,D. E. Galli
Physics , 2009, DOI: 10.1063/1.3247833
Abstract: Generally ``exact'' Quantum Monte Carlo computations for the ground state of many Bosons make use of importance sampling. The importance sampling is based, either on a guiding function or on an initial variational wave function. Here we investigate the need of importance sampling in the case of Path Integral Ground State (PIGS) Monte Carlo. PIGS is based on a discrete imaginary time evolution of an initial wave function with a non zero overlap with the ground state, that gives rise to a discrete path which is sampled via a Metropolis like algorithm. In principle the exact ground state is reached in the limit of an infinite imaginary time evolution, but actual computations are based on finite time evolutions and the question is whether such computations give unbiased exact results. We have studied bulk liquid and solid 4He with PIGS by considering as initial wave function a constant, i.e. the ground state of an ideal Bose gas. This implies that the evolution toward the ground state is driven only by the imaginary time propagator, i.e. there is no importance sampling. For both the phases we obtain results converging to those obtained by considering the best available variational wave function (the Shadow wave function) as initial wave function. Moreover we obtain the same results even by considering wave functions with the wrong correlations, for instance a wave function of a strongly localized Einstein crystal for the liquid phase. This convergence is true not only for diagonal properties such as the energy, the radial distribution function and the static structure factor, but also for off-diagonal ones, such as the one--body density matrix. From this analysis we conclude that zero temperature PIGS calculations can be as unbiased as those of finite temperature Path Integral Monte Carlo.
Spectral evolution of Fermi/GBM short Gamma-Ray Bursts
G. Ghirlanda,G. Ghisellini,L. Nava,D. Burlon
Physics , 2010, DOI: 10.1111/j.1745-3933.2010.00977.x
Abstract: We study the spectral evolution of 13 short duration Gamma Ray Bursts (GRBs) detected by the Gamma Burst Monitor (GBM) on board Fermi. We study spectra resolved in time at the level of 2-512 ms in the 8 keV-35 MeV energy range. We find a strong correlation between the observed peak energy Ep and the flux P within individual short GRBs. The slope of the Ep P^s correlation for individual bursts ranges between ~0.4 and ~1. There is no correlation between the low energy spectral index and the peak energy or the flux. Our results show that in our 13 short GRBs Ep evolves in time tracking the flux. This behavior is similar to what found in the population of long GRBs and it is in agreement with the evidence that long GRBs and (the still few) short GRBs with measured redshifts follow the same rest frame Ep-Liso correlation. Its origin is most likely to be found in the radiative mechanism that has to be the same in both classes of GRBs.
Dynamic structure factor for 3He in two-dimensions
M. Nava,D. E. Galli,S. Moroni,E. Vitali
Physics , 2013, DOI: 10.1103/PhysRevB.87.144506
Abstract: Recent neutron scattering experiments on 3He films have observed a zero-sound mode, its dispersion relation and its merging with -and possibly emerging from- the particle-hole continuum. Here we address the study of the excitations in the system via quantum Monte Carlo methods: we suggest a practical scheme to calculate imaginary time correlation functions for moderate-size fermionic systems. Combined with an efficient method for analytic continuation, this scheme affords an extremely convincing description of the experimental findings.
Analysis of impulse oscillometric measures of lung function and respiratory system model parameters in small airway-impaired and healthy children over a 2-year period
Erika G Meraz, Homer Nazeran, Carlos D Ramos, Pat Nava, Bill Diong, Michael D Goldman
BioMedical Engineering OnLine , 2011, DOI: 10.1186/1475-925x-10-21
Abstract: Asthma (A) is the most prevalent chronic respiratory disease in children. Therefore, early and accurate assessment of respiratory function is of tremendous clinical interest in diagnosis, monitoring and treatment of respiratory conditions in this subpopulation.IOS has been successfully used to measure lung function in children with a high degree of sensitivity and specificity to small airway impairments (SAI) and asthma. IOS measures of airway function and equivalent electrical circuit models of the human respiratory system have been developed to quantify the severity of these conditions. Previously, we have evaluated several known respiratory models based on the Mead's model and more parsimonious versions based on fitting IOS data known as extended RIC (eRIC) and augmented RIC (aRIC) models have emerged, which offer advantages over earlier models.IOS data from twenty-six children were collected and compared during pre-bronchodilation (pre-B) and post- bronchodilation (post-B) conditions over a period of 2 years.Are the IOS and model parameters capable of differentiating between healthy children and children with respiratory system distress?Children were classified into two main categories: Healthy (H) and Small Airway-Impaired (SAI). The IOS measures and respiratory model parameters analyzed differed consistently between H and SAI children. SAI children showed smaller trend of "growth" and larger trend of bronchodilator responses than H children.The two model parameters: peripheral compliance (Cp) and peripheral resistance (Rp) tracked IOS indices of small airway function well. Cp was a more sensitive index than Rp. Both eRIC and aRIC Cps and the IOS Reactance Area, AX, (also known as the "Goldman Triangle") showed good correlations.What are the most useful IOS and model parameters?In this work we demonstrate that IOS parameters such as resistance at 5 Hz (R5), frequency-dependence of resistance (fdR: R5-R20), reactance area (AX), and parameter estimates of respira
Produ??o e crescimento da macieira 'Fuji' em resposta à aduba??o organica e manejo de plantas espontaneas
Nava, Gilberto;
Revista Brasileira de Fruticultura , 2010, DOI: 10.1590/S0100-29452010000400034
Abstract: organic fertilization and soil management can interfere directly on yield and growth of apple trees, especially in shallow soils. this study evaluates the influence of poultry litter rates and methods of weed control on yield and growth of apple trees. the experiment was carried out on an inceptisol, cultivated with apple for 13 years, cv. fuji on rootstock marubakaido, located in s?o joaquim, sc. since 1998, two methods of weed control were used, one with herbicide and other with mowing both associated with four poultry litter rates (0, 5, 10 and 20 t ha-1) applied annually to soil. the experimental design was complete randomized blocks, with split-plot arrangement and four replications. the yield of apple trees was increased by addition of poultry litter and it was dependent on the method of weed control. regarding the mowing method, it was necessary to apply a higher rate of organic fertilizer to achieve the same yield observed for the herbicide method. the application of litter poultry promoted the recovery of plant growth and in a more efficient way when herbicide was used as weed control.
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