Addressing the Natural Resource Curse: An Illustration from Nigeria

Some natural resources -- oil and minerals in particular -- exert a negative and nonlinear impact on growth via their deleterious impact on institutional quality. We show this result to be very robust. The Nigerian experience provides telling confirmation of this aspect of natural resources. Waste and corruption from oil rather than Dutch disease has been responsible for its poor long run economic performance. We propose a solution for addressing this resource curse which involves directly distributing the oil revenues to the public. Even with all the difficulties of corruption and inefficiency that will no doubt plague its actual implementation, our proposal will, at the least, be vastly superior to the status quo. At best, however, it could fundamentally improve the quality of public institutions and, as a result, transform economics and politics in Nigeria.

Unconventional superconducting pairing symmetry induced by phonons

The possibility of non-s-wave superconductivity induced by phonons is investigated using a simple model that is inspired by Sr$_2$RuO$_4$. The model assumes a two-dimensional electronic structure, a two-dimensional spin-fluctuation spectrum, and three-dimensional electron-phonon coupling. Taken separately, each interaction favors formation of spin-singlet pairs (of s symmetry for the phonon interaction and d$_{x^2-y^2}$ symmetry for the spin interaction), but in combination, a variety of more unusual singlet and triplet states are found, depending on the interaction parameters. This may have important implications for Sr$_2$RuO$_4$, providing a plausible explanation of how the observed spin fluctuations, which clearly favor d$_{x^2-y^2}$ pairing, may still be instrumental in creating a superconducting state with a different (e.g., p-wave) symmetry. It also suggests an interpretation of the large isotope effect observed in Sr$_2$RuO$_4$. These results indicate that phonons could play a key role in establishing the order-parameter symmetry in Sr$_2$RuO$_4$, and possibly in other unconventional superconductors.Comment: 6 pages, 5 figures, submitted to Phys. Rev.

GM crops and gender issues

Correspondence in the December issue by Jonathan Gressel not only states that gender issues in rural settings have not been adequately addressed with respect to weed control biotech but also asserts that such technology can increase the quality of life of rural women in developing countries. Improved weed control is a labor-saving technology that can result in less employment in a labor surplus rural economy. Often in rural areas, wage income is the main source of income and an important determinant of the quality of life, particularly where employment opportunities are generally limited. Apart from soil preparation, planting and weeding, harvesting is also 'femanual' work that can generate more employment if yields are higher. Biotech can enhance the quality of life of women but only if the technology is associated with overall generation of rural employment

Non-collinear Magnetic Order in the Double Perovskites: Double Exchange on a Geometrically Frustrated Lattice

Double perovskites of the form A_2BB'O_6 usually involve a transition metal ion, B, with a large magnetic moment, and a non magnetic ion B'. While many double perovskites are ferromagnetic, studies on the underlying model reveal the possibility of antiferromagnetic phases as well driven by electron delocalisation. In this paper we present a comprehensive study of the magnetic ground state and T_c scales of the minimal double perovskite model in three dimensions using a combination of spin-fermion Monte Carlo and variational calculations. In contrast to two dimensions, where the effective magnetic lattice is bipartite, three dimensions involves a geometrically frustrated face centered cubic (FCC) lattice. This promotes non-collinear spiral states and `flux' like phases in addition to collinear anti-ferromagnetic order. We map out the possible magnetic phases for varying electron density, `level separation' epsilon_B - epsilon_B', and the crucial B'-B' (next neighbour) hopping t'.Comment: 15 pages pdflatex + 19 figs, revision: removed redundant comment

A Unified treatment of small and large- scale dynamos in helical turbulence

Helical turbulence is thought to provide the key to the generation of large-scale magnetic fields. Turbulence also generically leads to rapidly growing small-scale magnetic fields correlated on the turbulence scales. These two processes are usually studied separately. We give here a unified treatment of both processes, in the case of random fields, incorporating also a simple model non-linear drift. In the process we uncover an interesting plausible saturated state of the small-scale dynamo and a novel analogy between quantum mechanical (QM) tunneling and the generation of large scale fields. The steady state problem of the combined small/large scale dynamo, is mapped to a zero-energy, QM potential problem; but a potential which, for non-zero mean helicity, allows tunneling of bound states. A field generated by the small-scale dynamo, can 'tunnel' to produce large-scale correlations, which in steady state, correspond to a force-free 'mean' field.Comment: 4 pages, 1 figure, Physical Review Letters, in pres

Giant Meterwave Radio Telescope observations of an M2.8 flare: insights into the initiation of a flare-coronal mass ejection event

We present the first observations of a solar flare with the GMRT. An M2.8 flare observed at 1060 MHz with the GMRT on Nov 17 2001 was associated with a prominence eruption observed at 17 GHz by the Nobeyama radioheliograph and the initiation of a fast partial halo CME observed with the LASCO C2 coronograph. Towards the start of the eruption, we find evidence for reconnection above the prominence. Subsequently, we find evidence for rapid growth of a vertical current sheet below the erupting arcade, which is accompanied by the flare and prominence eruption.Comment: Accepted for publication in Solar Physic

Associations between adult attachment and vision-related quality of life in visually impaired individuals

PURPOSE An attachment theory framework approach may allow insight into how social and psychosocial factors interact to impact vision-related quality of life (QoL). In this pilot study, we investigated potential associations between adult attachment style and visual function QoL of visually impaired individuals. METHODS We recruited 38 visually impaired individuals (15 females, 23 males; 51.8 ± 16.0 years). Visual function measures included distance and near visual acuity (VA) and contrast sensitivity. All participants completed: the 25-item National Eye Institute Visual Functioning Questionnaire-25 (NEI-VFQ 25) and the Experiences in Close Relationships–Relationships Structures questionnaire. RESULTS Presenting conditions included inherited retinal dystrophy (n = 10), nystagmus (n = 9), glaucoma (n = 7) and other eye conditions (n = 12). There was a statistically significant negative correlation between the NEI-VFQ-25 composite score (45.5 ± 14.7) and attachment-related anxiety (r = −0.352, p = 0.033). The latter correlation still held when controlling for participants’ level of vision (r = −0.352, p = 0.035). Despite the range of conditions and wide age range, these were not significantly correlated with any variable of interest in the current study. CONCLUSION Attachment-related anxiety ought to be taken into account when managing a visually impaired individual. Attachment-based approaches could be used to improve access to support services for visually impaired individuals, as well as self-management of their condition

Addressing the natural resource curse: An illustration from Nigeria

Some natural resources-oil and minerals in particular-exert a negative and nonlinear impact on growth via their deleterious impact on institutional quality. We show this result to be very robust. The Nigerian experience provides telling confirmation of this aspect of natural resources. Waste and corruption from oil rather than Dutch disease has been responsible for its poor long run economic performance. We propose a solution for addressing this resource curse which involves directly distributing the oil revenues to the public. Even with all the difficulties of corruption and inefficiency that will no doubt plague its actual implementation, our proposal will, at the least, be vastly superior to the status quo. At best, however, it could fundamentally improve the quality of public institutions and, as a result, transform economics and politics in Nigeria

An approach to dem material characterization in coheisve granular bulk solid materials

In bulk handling applications, such as conveying and storage, understanding the DEM particle characteristics to best simulate the flow of particulate systems at the macroscopic scale addresses an uncertainty in the DEM simulation of operational unit design and handling scenarios. This research provides a better understanding of the role adequate DEM material properties have on the flow-ability of bulk solid materials through the development, implementation and application of a generic material model procedure used in developing DEM input properties from physical testing data. This investigation proposes coupling physical material testing procedures with a DEM history dependent particle-particle macroscopic elasto-plastic adhesive contact model that accounts for both elastic and plastic contact deformations and cohesive attractions [1, 2]. The research application tasks are focused on three major areas: 1) measure a bulk solid’s cohesive and frictional properties under mass flow and pressure, 2) simulate each material sample through a series of test controlled standards, 3) verify the suitable predicted material properties in the test applications simulate and are comparable to experimental results. As part of physical testing, such simulations can be used as part of the optimization for bulk handling design and operation