Caprinocultura e ovinocultura: crescimento promissor x desorganização preocupante.

bitstream/item/52348/1/Midia-Caprinocultura-e-ovinocultura.pd

The use of linear programming to evaluate the impact of credit for investments in small goat farms.

Abstract: The PRONAF is a governmental program that subsidies the credit for investment to smallholder farming and improves the social development in Brazil. This research was carried out to evaluate the effect of increasing the values of credit for investment used for the PRONAF farmers in semi-arid areas, and their impact in the income and labor in smallholder farming production system. Economic data of dairy and meat goat systems of PRONAF farmers in ?Rio Grande do Norte?, Brazil was used. The limit of the model was the credit for investment, maximum number of animals in the system and the labor time. The current values of credit for investment (US$ 2,850.00) were increased by 25%, 50% and 100% and its impact analyzed in the farm income when considering milk and meat production. The maximum number of animals in the system was estimated by multiplying the carry capacity (1.5 heads/ha/year) plus the average pasture areas of PRONAF farms (35 ha). The maximum labor time, available for farm work, was 12 hours/day. This mathematical model was solved using linear programming with LINDO® software. When the credit for investment was expanded in 25 and 50%, the income of the system increased, respectively, to 22 and 41%. It happened because the values of credit allowed increasing the number of dairy goats in the system. However, this income was not enough to use and pay more than 5 hours/day in dairy goat system activities. When raising the credit for investment up to 100% it could increase the income of the system around 81%. It happened because the number of dairy goats grew up to 83% and the dairy production had better results than meat production. The system with more dairy goats produces enough income as to pay the farmer labor (7 hours/day) and during the other five hours could develop other activities. Therefore, the results of the analysis indicated that an increase in the credit for investment in small goat farms in semi-arid areas in Brazil could be addressed towards the dairy goat production, enhancing the income of families and employment opportunities.Edição de proceedings 9th International Goat Conference; 23th Conference ofthe Asociación Mexicana de Producción Caprinaat Queretaro, Mexico, in September 2008. XXIII Conference ofthe Asociación Mexicana de Producción Caprin

Group theory analysis of electrons and phonons in N-layer graphene systems

In this work we study the symmetry properties of electrons and phonons in graphene systems as function of the number of layers. We derive the selection rules for the electron-radiation and for the electron-phonon interactions at all points in the Brillouin zone. By considering these selection rules, we address the double resonance Raman scattering process. The monolayer and bilayer graphene in the presence of an applied electric field are also discussed.Comment: 8 pages, 6 figure

Precisão experimental na predição de valores genéticos de progênies de arroz.

O objetivo deste trabalho foi comparar a eficiência do método de Papadakis, na correção da variação ambiental, com os delineamentos em blocos ao acaso e látice

Potencial genético de progênies de arroz irrigado avaliado por meio do método de Papadakis.

Este trabalho foi realizado no ano agrícola de 2012/2013, com o objetivo de comparar a eficiência do método de Papadakis na correção da variação ambiental em relação ao delineamento látice.Apresentação oral - Pós-graduação

Visual Binaries in the Orion Nebula Cluster

We have carried out a major survey for visual binaries towards the Orion Nebula Cluster using HST images obtained with an H-alpha filter. Among 781 likely ONC members more than 60" from theta-1 Ori C, we find 78 multiple systems (75 binaries and 3 triples), of which 55 are new discoveries, in the range from 0.1" to 1.5". About 9 binaries are likely line-of-sight associations. We find a binary fraction of 8.8%+-1.1% within the limited separation range from 67.5 to 675 AU. The field binary fraction in the same range is a factor 1.5 higher. Within the range 150 AU to 675 AU we find that T Tauri associations have a factor 2.2 more binaries than the ONC. The binary separation distribution function of the ONC shows unusual structure, with a sudden steep decrease in the number of binaries as the separation increases beyond 0.5", corresponding to 225 AU. We have measured the ratio of binaries wider than 0.5" to binaries closer than 0.5" as a function of distance from the Trapezium, and find that this ratio is significantly depressed in the inner region of the ONC. The deficit of wide binaries in the central part of the cluster is likely due to dissolution or orbital change during their passage through the potential well of the inner cluster region. Many of the companions are likely to be brown dwarfs.Comment: 27 pages, 10 figures, 2 tables, accepted by the Astronomical Journa

Comparison of 120Sn(6He,6He)120Sn and 120Sn(alpha,alpha)120Sn elastic scattering and signatures of the 6He neutron halo in the optical potential

Cross sections of $^{120}$Sn($\alpha$,$\alpha$)$^{120}$Sn elastic scattering have been extracted from the $\alpha$ particle beam contamination of a recent $^{120}$Sn($^6$He,$^6$He)$^{120}$Sn experiment. Both reactions are analyzed using systematic double folding potentials in the real part and smoothly varying Woods-Saxon potentials in the imaginary part. The potential extracted from the $^{120}$Sn($^6$He,$^6$He)$^{120}$Sn data may be used as the basis for the construction of a simple global $^6$He optical potential. The comparison of the $^6$He and $\alpha$ data shows that the halo nature of the $^6$He nucleus leads to a clear signature in the reflexion coefficients $\eta_L$: the relevant angular momenta $L$ with $\eta_L \gg 0$ and $\eta_L \ll 1$ are shifted to larger $L$ with a broader distribution. This signature is not present in the $\alpha$ scattering data and can thus be used as a new criterion for the definition of a halo nucleus.Comment: 13 pages, 7 figures, accepted for publication in Phys. Rev.