Near-Threshold Production of omega Mesons in the pp -> pp omega Reaction

The total cross section for omega production in the pp -> pp omega reaction has been measured at five c.m. excess energies from 3.8 to 30 MeV. The energy dependence is easily understood in terms of a strong proton-proton final state interaction combined with a smearing over the width of the state. The ratio of near-threshold phi and omega production is consistent with the predictions of a one-pion-exchange model and the degree of violation of the OZI rule is similar to that found in the pi-p -> n omega/phi reactions.Comment: Report in LaTeX2e. 12 pages with 2 eps figure

Subthreshold K+ production in deuteron and alpha induced nuclear reactions

Double differential cross sections have been measured for pi+ and K+ emitted around midraidity in d+A and He+A collisions at a beam kinetic energy of 1.15 GeV/nucleon. The total pi+ yield increases by a factor of about 2 when using an alpha projectile instead of a deuteron whereas the K+ yield increases by a factor of about 4. According to transport calculations, the K+ enhancement depends both on the number of hadron-hadron collisions and on the energy available in those collisions: their center-of-mass energy increases with increasing number of projectile nucleons

Body weight gain and carcass yield of llamas (Lama glama) subjected tofattening under four feeding types

Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Producción AnimalEl objetivo del estudio fue evaluar la ganancia de peso y rendimiento de carcasa dellamas machos diente de leche sometidas a engorde con cuatro tipos de alimentación (T1:Pastura natural; T2: T1 + dosificación vitamínica; T3: T1 + heno de alfalfa; T4: T2 + henode alfalfa). Se utilizó un diseño completamente al azar con arreglo factorial de 2x2 con unanálisis de covarianza (peso vivo inicial como covariable). Se emplearon 32 llamas asig-nadas al azar a uno de los cuatro tratamientos por 84 días. La carga animal empleada fuede 1.3 unidades llama/ha. La ganancia diaria de peso (GDP) se evaluó en los periodos deengorde a 14, 28, 42, 56, 70 y 84 días. La GDP por periodo de engorde fue significativamentediferente entre periodos, donde los primeros tres periodos (14, 28 y 42 días) mostraronmejor GDP (337, 237 y 160 g/d, respectivamente). La GDP por tipo de alimentación fuemayor en T3 (157 g/d) durante el periodo de 84 días (p<0.01) y el mejor rendimiento decarcasa se obtuvo en T4 (53.60%) seguido por el T3 (53.20%) (p<0.01). Se concluye quela mayor GDP se logra hasta los 42 días y el mejor rendimiento de carcasa se logra en lapastura natural + suplementación con heno de alfalfa (T3)The aim of this study was to evaluate the bodyweight gain and carcass yield ofyoung male llamas (milk tooth) subjected to fattening with four types of feeding (T1:Natural pasture; T2: T1 + vitamin injection; T3: T1 + alfalfa hay; T4: T2 + hay alfalfa). A completely randomized design with a 2x2 factorial arrangement with a covariance analysis(initial live weight as covariate) was used. Thirty-two llamas were randomized assignedto one of the four treatments for 84 days. The stocking rate was 1.3 animal units/ha. Dailyweight gain (DWG) was evaluated in the fattening periods at 14, 28, 42, 56, 70 and 84days. The DWG per fattening period was significantly different between periods, in thefirst three periods (14, 28 and 42 days) showing the best DWG (337, 237 and 160 g/d,respectively). The DWG per feed type was higher in T3 (157 g/d) during the 84-dayperiod (p<0.01) and the best carcass yield was obtained in T4 (53.60%) followed by T3(53.20%) (p<0.01). It is concluded that the highest DWG is achieved at day 42 and thebest carcass yield is obtained with natural pasture + alfalfa hay supplementation (T3)

Comparison of eta and eta' production in the pp -> pp eta(eta') reactions near threshold

The total cross section of the pp -> pp eta' reaction has been measured at two energies near threshold by detecting the final protons in a magnetic spectrometer. The values obtained are about a factor of 70 less than for the corresponding eta production, in good agreement with the predictions of a one-pion-exchange model.Comment: 10 pages, Latex with 3 eps figure

Polarisation of the omega meson in the pd-->3He+omega reaction at 1360 and 1450 MeV

The tensor polarisation of omega mesons produced in the pd-->3He+omega reaction has been studied at two energies near threshold. The 3He nuclei were detected in coincidence with the pi0pi+pi- or pi0gamma decay products of the omega. In contrast to the case of phi meson production, the omega mesons are found to be unpolarised. This brings into question the applicability of the Okubo-Zweig-Iizuka rule when comparing the production of vector mesons in low energy hadronic reactions.Comment: 11 pages, 4 figure

The pd --> ^3He eta pi0 reaction at T_p = 1450 MeV

The cross section for the pd --> ^3He eta pi0 reaction has been measured at a beam energy of 1450 MeV using the WASA detector at the CELSIUS storage ring and detecting one ^3He and four photons from the decays of the two photons. The data indicate that the production mechanism involves the formation of the Delta(1232) isobar. Although the beam energy does not allow the full peak of this resonance to be seen, the invariant masses of all three pairs of final state particles are well reproduced by a phase space Monte Carlo simulation weighted with the p-wave factor of the square of the pi^0 momentum in the ^3Hepi^0 system.Comment: 10 pages, 5 figure

Eta-Helium Quasi-Bound States

The cross section and tensor analysing power t_20 of the d\vec{d}->eta 4He reaction have been measured at six c.m. momenta, 10 < p(eta) < 90 MeV/c. The threshold value of t_20 is consistent with 1/\sqrt{2}, which follows from parity conservation and Bose symmetry. The much slower momentum variation observed for the reaction amplitude, as compared to that for the analogous pd->eta 3He case, suggests strongly the existence of a quasi-bound state in the eta-4He system and optical model fits indicate that this probably also the case for eta-3He.Comment: LaTeX, uses elsart.sty, 10 pages, 3 Postscript figures, Submitted to Physics Letters

Scaling up community-based goat breeding programmes via multi-stakeholder collaboration

Community-based livestock breeding programmes (CBBPs) have emerged as a potential approach to implement sustainable livestock breeding in smallholder systems. In Malawi and Uganda, goat CBBPs were introduced to improve production and productivity of indigenous goats through selective breeding. Scaling up CBBPs have recently received support due to evidence-based results from current implementation and results of CBBPs implemented in other regions of the world. This paper explores strategies for scaling up goat CBBPs in Malawi and Uganda, and documents experiences and lessons learned during implementation of the programme. A number of stakeholders supporting goat-based interventions for improving smallholders’ livelihoods exists. This offers an opportunity for different actors to work together by pooling financial resources and technical expertise for establishment and sustainability of goat CBBPs. Scaling up strategies should be an integral part of the pilot design hence dissemination partners need to be engaged during the design and inception stages of the pilot CBBPs. Creation of self-sustaining CBBPs requires early collaborative programme planning, meaningful investment and long-term concerted and coordinated efforts by collaborating partners. Permanently established actors, like government agencies and research and training institutions, are better placed to coordinate such efforts. The overall goal of the scaling up programme should be creation of a financially sustainable system, in which smallholders are able, on their own, to transact and sustain operations of their local breeding institutions using locally generated revenue/ resources. Since CBBP scaling up is a ‘learning by doing process’, an effective monitoring and evaluation system should be an integral part of the process