Migration and animal husbandry: Competing or complementary livelihood strategies. Evidence from Kyrgyzstan

Animal husbandry and labour migration are important livelihood strategies for a large proportion of the rural population in developing countries. Up to now, the two strategies have usually been studied by looking at either one or the other; their interlinkages have rarely been examined. Based on a case study in rural Kyrgyzstan, the aim of this paper is to explore the links between animal husbandry and labour migration. Results show that for most rural households, livestock is crucial yet not sufficient to make a living. Therefore, many people diversify their income sources by migrating to work elsewhere. This generates cash for daily expenses and the acquisition of new livestock, but also leads to an absence of workforce in households. Yet since remittances usually exceed the expenses for hiring additional workforce, most people consider migration profitable. From a socio-economic point of view, migration and animal husbandry can thus be considered important complementary livelihood strategies for the rural Kyrgyz population, at least for the time being. In the long term, however, the failure of young migrants to return to rural places and their settlement in urban areas might also cause remittance dependency and lead to an increasing lack of qualified labour. From an environmental point of view, the investment of remittances into animal husbandry poses challenges to sustainable pasture management. Increasing livestock numbers in rural areas raise pressure on pasture resources. Since most people consider animal husbandry their main future prospect while continuing to use pastures in a fairly unsustainable way, this may further exacerbate the over-utilization of pastures in future

Correlation effects in the density of states of annealed GaMnAs

We report on an experimental study of low temperature tunnelling in hybrid NbTiN/GaMnAs structures. The conductance measurements display a root mean square V dependence, consistent with the opening of a correlation gap in the density of states of GaMnAs. Our experiment shows that low temperature annealing is a direct empirical tool that modifies the correlation gap and thus the electron-electron interaction. Consistent with previous results on boron-doped silicon we find, as a function of voltage, a transition across the phase boundary delimiting the direct and exchange correlation regime.Comment: Replaced with revised version. To appear in Phys. Rev.

Field-induced domain wall propagation: beyond the one-dimensional model

We have investigated numerically the field-driven propagation of perpendicularly magnetized ferromagnetic layers. It was then compared to the historical one-dimensional domain wall (DW) propagation model widely used in spintronics studies of magnetic nanostructures. In the particular regime of layer thickness (h) of the order of the exchange length, anomalous velocity peaks appear in the precessional regime, their shape and position shifting with h. This has also been observed experimentally. Analyses of the simulations show a distinct correlation between the curvature of the DW and the twist of the magnetization vector within it, and the velocity peak. Associating a phenomenological description of this twist with a four-coordinate DW propagation model, we reproduce very well these kinks and show that they result from the torque exerted by the stray field created by the domains on the twisted magnetization. The position of the peaks is well predicted from the DW's first flexural mode frequency, and depends strongly on the layer thickness. Comparison of the proposed model to DW propagation data obtained on dilute semiconductor ferromagnets GaMnAs and GaMnAsP sheds light on the origin of the measured peaks

Variations in vascular access flows in haemodialysis can depend on needle orientation

Introduction: While using the Transonic Qc[TM] machine to assess access flow in arteriovenous fistulae (AVF), we observed that when compared to antegrade arterial needle insertion, retrograde arterial needle insertion could regularly produce lower access flow measurements. This study sought to explore this phenomenon. Method: 23 patients entered and 20 finished the study. Patient selection criteria included: functioning AVF and an adequate AVF length for either retrograde or antegrade arterial needle insertion. After ensuring stable and similar blood pressures, 3 flow measurements were taken during the first 2 hours on the same dialysis day of 3 consecutive weeks using antegrade needle insertion then were repeated on 3 further consecutive weeks using retrograde insertion. Results: Overall, access flows measured with retrograde insertion were significantly lower by a mean difference of 107.15 ml/min (57-484 ml/min) than the flows measured with antegrade needle placement. In 5/20, 3 recorded minimal difference and 2 had a higher access flows during retrograde insertion. No recirculation was observed during either antegrade or retrograde needle insertion. The paired t-test showed that there was significant difference between the antegrade versus retrograde mean measurements (p = 0.005). Conclusion: Although the sample size is small and the number of measurements limited, we conclude that access flows may be greater with an antegrade arterial orientation compared to flows recorded with a retrograde orientation. The phenomenon behind this conclusion is yet to be investigated. We suggest that when using the Transonic Qc[TM] access measurement device the arterial needle should always be in the same direction for each measurement for each individual patient.<br /