The role of social networks in development of small-scale enterprises in the Chimanimani district of Zimbabwe

The past decade has witnessed an increased interest in the concept of social networks after the seminal theses of Coleman (1988) and Putnam (1993). An area that has attracted a great deal of interest is the value of social networks in small-scale enterprise development. This paper interrogates the role of social networks in the establishment and expansion of rural non-farm enterprises in the Chimanimani district of Zimbabwe and established that rural non-farm entrepreneurs resort to their social networks for information and other resources needed to establish and expand their enterprises, and that there are some gender differences in the use of the various social networks.Social networks, rural non-farm entrepreneurs, rural non-farm enterprises, Agribusiness,

Producer support estimate (PSE) for South African agriculture for 1996, 1997, 1998

This paper endeavours to update the series of PSE calculations based on the 1998 OECD methodology (OECD 1998) which is a slightly revised methodology from the earlier calculations. The OECD terminology also now means that PSE stands for Producer Support Estimate and is calculated by classifying policy measures under a slightly different set of categories.Agricultural Finance,

Persistent puhnonary hypertension of the neonate in a developing country - does extracorporeal metnbrane oxygenation have a role to play?

A retrospective study was undertaken of survival after conventional management of 35 infants suffering from persistent pubnonary hypertension of the neonate (PPHN). The outcome of infants weighing more than 2 000 g and who also qualified for extracorporeal membrane oxygenation (ECMO) therapy on the grounds of published criteria was assessed. The admission incidence ofpatients with PPHN was 1,10/0. Secondary PPHN was more common than primary. The overall survival rate of 69% in this study reflects the trend in recently reported iInproved survival rates of infants with PPHN, treated with conventional techniques. Sixteen of 28 infants weighing more than 2 000 g qualified for ECMO therapy; 4 of them died. Had ECMO been available as an alternative Inode of therapy, only 2 of the 4 Inight have been saved. The other 2 were considered to have conditions incoInpatible with a nomal quality of life. We therefore assessed the requirement for ECMO in our population to be approxiInately 0,6/1 000 live births. Although ECMO Inay be proInising, the introduction of this technique in developing countries should rather be delayed until more substantial data refute this. Because PPHN could be related to a potential preventable cause in almost 800/0 of cases, we propose the support of more cost-effective strategies such as continuing obstetric and perinatal education programmes

Significance of zero modes in path--integral quantization of solitonic theories with BRST invariance

The significance of zero modes in the path-integral quantization of some solitonic models is investigated. In particular a Skyrme-like theory with topological vortices in (1+2) dimensions is studied, and with a BRST invariant gauge fixing a well defined transition amplitude is obtained in the one loop approximation. We also present an alternative method which does not necessitate evoking the time-dependence in the functional integral, but is equivalent to the original one in dealing with the quantization in the background of the static classical solution of the non-linear field equations. The considerations given here are particularly useful in - but also limited to - the one-loop approximation.Comment: 16 pages, LaTe

Quantum Tunneling and Phase Transitions in Spin Systems with an Applied Magnetic Field

Transitions from classical to quantum behaviour in a spin system with two degenerate ground states separated by twin energy barriers which are asymmetric due to an applied magnetic field are investigated. It is shown that these transitions can be interpreted as first- or second-order phase transitions depending on the anisotropy and magnetic parameters defining the system in an effective Lagrangian description.Comment: 18 pages, 7 figure

SUPPLY RESPONSE, DEMAND AND STOCKS FOR SOUTHERN AFRICAN BEEF

Livestock Production/Industries,

Pharmacy practice in a European perspective

In 1992 European pharmacy organisations joined in the EuroPtharm forum. This network has for the last two decades focused on development of pharmacy practice. Today 30 associations from 22 countries are members of the Forum.peer-reviewe

Entropy-based characterizations of the observable-dependence of the fluctuation-dissipation temperature

The definition of a nonequilibrium temperature through generalized fluctuation-dissipation relations relies on the independence of the fluctuation-dissipation temperature from the observable considered. We argue that this observable independence is deeply related to the uniformity of the phase-space probability distribution on the hypersurfaces of constant energy. This property is shown explicitly on three different stochastic models, where observable-dependence of the fluctuation-dissipation temperature arises only when the uniformity of the phase-space distribution is broken. The first model is an energy transport model on a ring, with biased local transfer rules. In the second model, defined on a fully connected geometry, energy is exchanged with two heat baths at different temperatures, breaking the uniformity of the phase-space distribution. Finally, in the last model, the system is connected to a zero temperature reservoir, and preserves the uniformity of the phase-space distribution in the relaxation regime, leading to an observable-independent temperature.Comment: 15 pages, 7 figure

Colloquium: Atomic spin chains on surfaces

In the present Colloquium, we focus on the properties of 1-D magnetic systems on solid surfaces. From the emulation of 1-D quantum phases to the potential realization of Majorana edge states, spin chains are unique systems to study. The advent of scanning tunnelling microscope (STM) based techniques has permitted us to engineer spin chains in an atom-by-atom fashion via atom manipulation and to access their spin states on the ultimate atomic scale. Here, we present the current state of research on spin correlations and dynamics of atomic spin chains as studied by the STM. After a brief review of the main properties of spin chains on solid surfaces, we classify spin chains according to the coupling of their magnetic moments with the holding substrate. This classification scheme takes into account that the nature and lifetimes of the spin-chain excitation intrinsically depend on the holding substrate. We first show the interest of using insulating layers on metals, which generally results in an increase in the spin state's lifetimes such that their quantized nature gets evident and they are individually accessible. Next, we show that the use of semiconductor substrates promises additional control through the tunable electron density via doping. When the coupling to the substrate is increased for spin chains on metals, the substrate conduction electron mediated interactions can lead to emergent exotic phases of the coupled spin chain-substrate conduction electron system. A particularly interesting example is furnished by superconductors. Magnetic impurities induce states in the superconducting gap. Due to the extended nature of the spin chain, the in-gap states develop into bands that can lead to the emergence of 1-D topological superconductivity and, consequently to the appearance of Majorana edge states