Runoff irrigation practices and challenges in western lowlands of Eritrea

Introduction. The arid and semi-desert lowland agro-ecological zones of Eritrea experience lowprecipitation, much lower than the requirements forrobust agricultural production unless supplemented by properly functioning runoff irrigation systems. However, an in-depth understandingof the principles and practices of runoff irrigation, identification of itspotentials and challengesand come up with viable solutions is necessary. Materials and methods. Qualitative and quantitative, descriptive and analytical research methodologies are applied. Primary and secondary data are used to identify existing constraints. Besides, global and regional databases are extensively utilized to fill information gaps. Results. The total potential cultivable land of Eritrea amounts to 2.1 million ha, out of which 71.4 % is rainfed and 28.6 % is irrigation. But, the potential irrigable land as reported by FAO is much lower (187,500 ha), out of which 50,000 ha is within the Western Lowlands. Considering such disparities and the less likely scenario of lowest irrigation potential, the actual equipped for spate irrigation at national level would amount to only 33.6 %, meaning there are still a lot of possibilities for expansion. The causes of malfunctioning of the existing systems are associated to structural, operation and maintenance, and management. Lack of historical hydrological data is among the highly likely reasons, which in turn greatly affects hydrological simulations. Conclusions. Despitecommendable efforts made to expand the improved runoff irrigation in the Western Lowlands, most of the projectshavefailed to achieve the intended purposes. Thus, comprehensive and simple mathematical modelsfor ma­king hydrological predictions have been suggested.

Beyond Financialisation: The Need for a Longue Durée Understanding of Finance in Imperialism

One of the central premises of the literature on financialisation is that we have been living in a new era of capitalism, characterised by a historical shift in the finance-production nexus. Finance has begun to behave ‘abnormally’ towards production. It has expanded to a disproportionate economic size and, more importantly, has divorced from ‘legitimate’ economic pursuits. In this paper we explore these claims of ‘expansion’ and ‘divorce’. We argue that although there has been expansion of financial motives and practices the ‘divorce’ between the financial and the productive economy cannot be considered a new empirical phenomenon having occurred during the last decades and even less an epochal shift of the capitalist system. The neglect of the needs of a self-centered economy has been the ‘normal’ and structural operation of finance in most of the former European colonies in the Global South during the last 150 years. We provide evidence to that effect with a longue durée study of the finance-production nexus in Senegal and Ghana. A main result of our empirical exploration is that an understanding of the historical developments of finance under colonialism is key for understanding how capitalist finance works globally. Such a de-centered perspective requires however a serious engagement with the concept and logics of imperialism.

A model for the structure of metallic glasses based on chemical twinning

A model for transition-metal-metalloid glasses has been constructed and refined by energy minimization with the use of a Lennard-Jones 6-12 potential. The model is based on the concept that domains of positionally correlated atoms exist in these glasses on a scale of 1-2 nm. Within each domain, positional order is governed by rules appropriate to a single type of structural operation (simple chemical twinning in this case) acting in a prescribed direction. (The structure of compositionally equivalent crystalline phases may be represented by similar rules acting over essentially infinite domains.) Positions of atoms in the interface between domains are defined by two (or more) operations appropriate to each of the bounding domains so that the structure has a high degree of homogeneity. Computed properties are compared with experimental structural data for a number of typical amorphous transition-metal-metalloid alloys. Agreement between experimental and calculated partial pair-correlation functions and structure factors is good, supporting the notion of extensive local and medium-range positional order in these alloys. Moreover, the discrepancies that exist between model data and experimental results suggest that the model is less ordered than an actual glass. This model provides some insight into the nature of local geometrical distortions of structural units, coupling between positional and compositional fluctuations and the relative stability of glassy and microcrystalline alloys.