Monte Carlo simulations of ordering in ferromagnetic-antiferromagnetic bilayers

Monte Carlo simulations have been used to study phase transitions on coupled anisotropic ferro/antiferromagnetic (FM/AFM) films of classical Heisenberg spins. We consider films of different thicknesses, with fully compensated exchange across the FM/AFM interface. We find indications of a phase transition on each film, occuring at different temperatures. It appears that both transition temperatures depend on the film thickness.Comment: Revtex, 4 pages, 4 figure

Optical controlling of a chemical reaction

The present invention relates to a device for enabling an optically controlled chemical reaction in a reaction chamber; it comprises a substrate on a removable cartridge for binding at least one molecule on a first surface of the substrate, an optical arrangement configured to direct cleavage light to the substrate to optically induce a photochemical cleavage reaction, and a wiregrid further thermally coupled to a heat conductive element. Such a device can be used for example to carry out an optically controlled chemical reaction, particularly a nucleic sequencing reaction. It can be used to carry out reactions with an increased throughput without overheating the device itself or the reagents used

The water acts in the Nyachowa catchment area

A research paper on how water is utilized by rural small-holder farmers in Zimbabwe.This chapter deals with a catchment area in Mutare district: that of the Nyachowa river and its tributaries.2 The catchment area is made up of lands belonging to Shigodora commercial farm and Zimunya communal area. Our interest is the use of its waters. Irrigation infrastructure was developed by both the commercial and communal farmers at the beginning of this century. Since then water demand has increased whilst the catchment has gradually yielded less. In this chapter we attempt to understand how various people with a stake in Nyachowa waters have coped with this situation of competing interests, and what role formal and perceived rights to Nyachowa water has played. On the basis of the Nyachowa experience we wish to contribute to the current discussions in Zimbabwe on reform of the Water Act.3 The problems experienced in the Nyachowa catchment area are epitomised by the Nyachowa Irrigation Scheme (‘the Scheme’). This Scheme was constructed during the 1930s and was assigned an irrigated area of 50 hectares in 1934 by the agriculturalist Alvord who had assisted with its design (Roder, 1965: 106). The last entry in the archival documents concerning the scheme is 1938, reappearing again only in 1954. It is not clear what happened between 1938 and 1954, but during those years ‘African irrigators presumably managed their land without government aid’ (Roder, 1965: 108). In 1961, Roder reports the scheme to be operational. The 28 plot-holders cultivated 45 hectares obtaining maize yields of 1,400 kg per hectare.4 Since the 1980s the plot-holders have received no appreciable water from the Nyachowa river.5 It is therefore doubtful whether we can still speak of the existence of this scheme. Yet it exists in the minds of one-time irrigators and officials.The Netherlands Organisation for International Cooperation in Higher Education (NUFFIC

Correlation and causation between the UN Human Development Index and national and personal wealth and resource exploitation

Human development is increasingly on global policy agendas, in particular related to the Sustainable Development Goals. Here, the UN Human Development Index is analysed for correlation and causation with economic and resource parameters using novel quantitative techniques. Global datasets at national resolution are used to explore correlation and causation with the HDI. The whole HDI is not correlated to national totals of wealth or resource use, but is strongly correlated to personal wealth and resource use. The multi-spatial convergence cross mapping method is adapted to shed light on causation in this system. It is shown that the HDI is tightly linked to the economy and to personal resource use. Analysis of the HDI sub-indices reveals subtleties easily overlooked. For example, it is shown that access to water and electricity strongly influence GNI. It is shown that simple resource accumulation/exploitation is less important in determining HDI growth than personal wealth and access to resources. That is, equitable distribution is more effective than gross accumulation in influencing the HDI. Strong feedback means that investments in water treatment and distribution networks, for example, will have strong effects on HDI change, a conclusion that may play an important role in national developmental policy debate