Quantization of the electromagnetic field outside static black holes and its application to low-energy phenomena

We discuss the Gupta-Bleuler quantization of the free electromagnetic field outside static black holes in the Boulware vacuum. We use a gauge which reduces to the Feynman gauge in Minkowski spacetime. We also discuss its relation with gauges used previously. Then we apply the low-energy sector of this field theory to investigate some low-energy phenomena. First, we discuss the response rate of a static charge outside the Schwarzschild black hole in four dimensions. Next, motivated by string physics, we compute the absorption cross sections of low-energy plane waves for the Schwarzschild and extreme Reissner-Nordstr\"om black holes in arbitrary dimensions higher than three.Comment: 26 pages (revtex), no figures, misprints in some conditions correcte

Myocardial FFR (Fractional Flow Reserve) in patients with angiographically intermediate coronary artery stenosis - an initial institutional experience

Background: The clinical significance of coronary artery stenosis of intermediate severity can be difficult to determine. The management of intermediate coronary lesions, defined by a diameter stenosis of ≥40% to ≤70%, continues to be a therapeutic dilemma for cardiologists. The 2-dimensional representation of the arterial lesion provided by angiography is limited in distinguishing intermediate lesions that require stenting from those that simply need appropriate medical therapy. In the era of drug-eluting stents, some might propose that stenting all intermediate coronary lesions is an appropriate solution. However, the possibility of procedural complications such as coronary dissection, no reflow phenomenon, in-stent restenosis, and stent thrombosis requires accurate stratification of patients with intermediate coronary lesions to appropriate therapy. Myocardial fractional flow reserve (FFR) is an index of the functional severity of coronary stenosis that is calculated from pressure measurements made during coronary angiography. The objective of the study is to evaluate the usefulness of FFR in patients with angiographically intermediate coronary artery stenosis.Methods: 20 patients with intermediate coronary stenosis and chest pain of uncertain origin. The Exercise Electrocardiography (TMT), Myocardial Perfusion Imaging study (MPI), Quantitative Coronary Angiography (QCA) were compared with the results of FFR measurements.Results: 20 patients were undergone FFR measurement during the study period. With the mean age of 57.25±11.2 and male patients were 16 (80%), female patients 4 (20%), in all 13 patients with an FFR of 0.75 tested negative for reversible myocardial ischemia on TMT and MPI study. No revascularization procedures were performed in 7 (35%) patients, and no adverse cardiovascular events were noted in all these patients during 6 months of follow-up.Conclusions: In patients with coronary stenosis of intermediate severity, FFR appears to be a useful index of the functional severity of the stenosis and the need for coronary revascularization.

Assessment of Skempton's pore water pressure parameters B and A using a high-capacity tensiometer

Saturation of soils is a prerequisite in many laboratory tests involving consolidation, permeability and stress-strain behaviour. The saturation process is usually time consuming, particularly in clay-rich soils, and this can incur substantial cost and potential delays in reporting findings. The saturation of samples is assessed using the well-established Skempton's pore water pressure parameter B. In a situation where the soil is fully saturated the B-value is approximately one. It is often the case that fine soil samples extracted from the ground, particularly those from below the water table, remain saturated. However, current testing protocols require evidence to verify a complete saturation prior to subsequent laboratory investigations. This paper reports experimental results exploring the hypothesis that, if the sample is ‘perceived’ to be saturated, then further saturation procedures may not be necessary to obtain reliable geotechnical parameters. Laboratory investigations were conducted on three different clays (Kaolin Clay, Belfast Clay and Oxford Clay) in a testing chamber instrumented with a high capacity tensiometer. The confining pressures were applied in a ramped fashion under undrained conditions. The response of the tensiometer confirmed that the samples were saturated from the very beginning of the loading process, as implied by the B-value being close to one. Further supplementary investigations were carried out to assess the Skempton's pore water pressure parameter A and the stress-strain behaviour of the soils. The combined finding provides further evidence to suggest that the saturation process as suggested in standards may not be necessary for fine grained soils to establish reliable geotechnical design parameters

Increasing Compliance with Mass Drug Administration Programs for Lymphatic Filariasis in India through Education and Lymphedema Management Programs

Global elimination of lymphatic filariasis requires giving drugs at least annually to populations who live at risk of becoming infected with the parasite. At least 80% of people at risk need to take the drugs annually for 5 or more years to stop transmission of the infection. People suffering from the long-term effects of infection, such as swollen legs, benefit from programs that teach self-care of their affected limbs. In this study, we assessed the impact of an educational campaign that, after addressing previously identified predictors of compliance, significantly improved drug compliance. The specific factors improving compliance included knowing about the drug distribution in advance, knowing that everyone is at risk for acquiring the infection, knowing that the drug distribution was for lymphatic filariasis prevention, and knowing at least one component of leg care. We also found that areas with programs to assist people with swollen legs had greater increases in compliance. This research provides evidence that program evaluation can be used to improve drug compliance. In addition, our work shows for the first time that programs to benefit people with swollen legs caused by lymphatic filariasis also increase the participation of people without disease in drug treatment programs

Database for grain Fe and Zn in sorghum – A proposal

Sorghum (Sorghum bicolor) is the fifth most important cereal staple crop in subtropical and semi-arid regions of Africa and Asia (Reddy et al. 2011). It is the second cheapest source of energy and micronutrients, after pearl millet (Pennisetum glaucum) with a vast majority of the population in Africa and Central India depending on it for their dietary energy and micronutrient requirements (Parthasarathy Rao et al. 2006). Micronutrient malnutrition, primarily the result of diets deficient in bioavailable vitamins and minerals, causes blindness and anemia (even death) in more than half of the world’s population, especially among women of reproductive age, pregnant and lactating women and pre-school children (Underwood 2000, Sharma 2003, Welch and Graham 2004). Efforts are being made to provide fortified foods to these vulnerable groups. Biofortification, where possible, is the most costeffective and sustainable solution for tackling micronutrient deficiencies in developing countries of arid-tropical and subtropical regions as the intake of micronutrients is on a continuous basis with no additional cost to the consumer. Widespread interest is being shown in biofortification of sorghum by increasing mineral micronutrients [especially iron (Fe) and zinc (Zn)] in grains (Pfeiffer and McClafferty 2007, Ashok Kumar et al. 2009)

Increasing grain Fe and Zn concentration in sorghum: progress and way forward

Sorghum (Sorghum bicolor) is among the top ten crops that feed the world (Goldschein 2011). It is one of the cheapest sources of energy and micronutrients; and a vast majority of population in Africa and central India depend on sorghum for their dietary energy and micronutrient requirement (Parthasarathy Rao et al.). Micronutrient malnutrition, primarily the result of diets poor in bioavailable vitamins and minerals, causes blindness and anemia (even death) in more than half of the world’s population, especially among women of reproductive age, pregnant and lactating women and pre-school children (Underwood 2000, Sharma 2003, Welch and Graham 2004); and efforts are being made to provide fortified foods to vulnerable groups of the society. Biofortification, where possible, is the most costeffective and sustainable solution for tackling micronutrient deficiencies as intake of micronutrients is on a continuing basis with no..

Biofortification for combating micronutrient malnutrition: Identification of commercial sorghum cultivars with high grain iron and zinc concentrations

Sorghum is the dietary staple of more than 500 million people over 30 countries in Africa and Asia. Per capita consumption is 75 kg/year in major sorghum areas in India. It is one of the cheapest sources of energy, protein, Fe and Zn and contributes to >50% of the Fe and Zn. ICRISAT is working on sorghum biofortification to develop micronutrient-dense (Fe and Zn) sorghum cultivars with increased nutrient bioavailability. A total of 63 commercial sorghum cultivars developed in India were used to assess the variability in the commercial sorghum cultivars that are currently being cultivated by sorghum farmers in India. The grain Fe and Zn concentrations were determined in the grain samples by using Atomic Absorption Spectrometer (AAS) and the X-ray fluorescence spectrometer (XRF). The mean grain Fe concentration in genotypes ranged from 22 to 44 mg/kg and grain Zn concentrations from 15 to 33 mg/kg. This variability was significant considering the base levels of grain Fe (30 mg/kg) and Zn (20 mg/kg) concentrations in sorghum. Highly significant positive correlation was found between the grain Fe and Zn concentration (r = 0.853; P <0.01). Compared to post-rainy sorghums predominantly grown for food use in India, the rainy season grown commercial hybrids possessed up to 50% higher Fe and Zn concentration

Characterization of InGaN/GaN multi-quantum-well blue-light-emitting diodes grown by metal organic chemical vapor deposition

The structural,surface morphology, and the temperature dependence photoluminescence of InGaN(3 nm)/GaN(7 nm) 5 period multi-quantum-well blue-light-emitting diode (LED)structures grown by metal organic chemical vapor deposition(MOCVD) have been studied. Quantum dot-likestructures and strain contrast evident by black lumps were observed in the quantum wells using high-resolution transmission electron microscopy(HRTEM) analysis. Double-crystal high-resolution x-ray diffraction (HRXRD) spectra of blue LED were simulated using kinematical theory method, to obtain composition, and period thickness of well and barrier. The “S” shape character shift as red–blue–redshift of the quantum-well emission line, i.e., blue emission peak 2.667 eV at 10 K, was observed with variation of temperature in the photoluminescence (PL) spectra. The shift is assigned to the potential fluctuations due to alloy inhomogeneous distribution in the quantum wells. The In composition in the quantum wells obtained by two independent techniques, namely HRXRD and PL, was 8% and 19%, respectively. The reason for this large difference in composition is explained in this letter