Magnetic properties of Hydrogenated Li and Co doped ZnO nanoparticles

The effect of hydrogenation on magnetic properties of Zn0.85Co0.05Li0.10O nanoparticles is presented. It was found that the sample hydrided at room temperature (RT) showed weak ferromagnetism (FM) while that hydrided at 400oC showed robust ferromagnetism at room temperature. In both cases reheating the sample at 400oC in air converts it back into paramagnetic state (P) completely. The characterization of samples by X-ray and electron diffraction (ED) showed that room temperature ferromagnetism observed in the samples hydrogenated at RT is intrinsic in nature whereas that observed in the samples hydrogenated at 400oC is partly due to the cobalt metal clusters.Comment: 10 pages, 3 figure

Surveys of Informal Sector Enterprises - Some Measurement Issues

The informal sector represents an important part of the economy and the labor market in many countries, especially developing countries. Measurements of the informal sector are of intrinsic interest in their own right and contribute toward exhaustive measures of gross domestic product (GDP). Considering that the informal sector provides employment for income creation to a large number of poor and contributes significantly to the GDP of many developing countries, collecting statistics through surveys for accurate measurement of output, net surplus, and value added is critical for national accountants, other users, and for researchers working on policy-related issues. As most of the informal sector enterprises do not maintain business accounts, the survey responses depend highly on the recall by the respondent and the skills of the interviewer. Thus, a very important aspect of the surveys of informal sector enterprises is the design of the survey questionnaire and the details to be captured in data collection in order to accurately measure the characteristics of these enterprises. The details sought in the survey questionnaire have implications on the accuracy of data and hence in the measurement of expenditure, receipts, profits, and gross value added (GVA) of these enterprises. In this paper we examine the differences in the measures of: (i) profits of an enterprise derived from a detailed set of questions on incomes and expenses, versus profits obtained through a single direct question; and (ii) GVA obtained using the production approach as the difference of output and intermediate consumption from a detailed set of questions on incomes and expenses, versus GVA using the income approach by asking a few questions on factor incomes, and a single direct question on profits. We use data from the 56th round survey of unorganized manufacturing conducted by the National Sample Survey Organization of India during the period July 2000–June 2001. We also examine if the differences vary with the characteristics of the enterprises, and suggest further empirical research to develop suitable tools for providing accurate measurements of informal sector enterprises

Geometrical dynamics of Born-Infeld objects

We present a geometrical inspired study of the dynamics of $Dp$-branes. We focus on the usual nonpolynomial Dirac-Born-Infeld action for the worldvolume swept out by the brane in its evolution in general background spacetimes. We emphasize the form of the resulting equations of motion which are quite simple and resemble Newton's second law, complemented with a conservation law for a worldvolume bicurrent. We take a closer look at the classical Hamiltonian analysis which is supported by the ADM framework of general relativity. The constraints and their algebra are identified as well as the geometrical role they play in phase space. In order to illustrate our results, we review the dynamics of a $D1$-brane immersed in a $AdS_3 \times S^3$ background spacetime. We exhibit the mechanical properties of Born-Infeld objects paving the way to a consistent quantum formulation.Comment: LaTex, 20 pages, no figure

Chiral Bosons Through Linear Constraints

We study in detail the quantization of a model which apparently describes chiral bosons. The model is based on the idea that the chiral condition could be implemented through a linear constraint. We show that the space of states is of indefinite metric. We cure this disease by introducing ghost fields in such a way that a BRST symmetry is generated. A quartet algebra is seen to emerge. The quartet mechanism, then, forces all physical states, but the vacuum, to have zero norm.Comment: 9 page

Medium optimization for the production of lipstatin by Streptomyces toxytricini using full factorial design of experiment

Abstract: Full factorial design of experiment for medium optimization was employed for lipstatin production by Streptomyces toxytricini in shake flask study. The full factorial DOE was very much effective in screening of nutritional parameters within the stipulated time frame in a limited number of experiments. A maximum lipstatin production was achieved 3.290 g/l with the following optimized factors: soya flour 35g/l and soya oil 25g/l. Validation experiments were also carried out to verify the adequacy and the accuracy of the model. The results also give a scope for large scale fermentation of lipstatin production. [Luthra, U., Kumar, H., Kulshreshtha, N., Tripathi, A., Trivedi, A., Khadpekar, S., Chaturvedi, A. and Dubey, R.C. Medium optimization for the production of lipstatin by Streptomyces toxytricini using full factorial design of experiment. Nat Sci 2013;1

New remarks on the linear constraint self-dual boson and Wess-Zumino terms

In this work we prove in a precise way that the soldering formalism can be applied to the Srivastava chiral boson (SCB), in contradiction with some results appearing in the literature. We have promoted a canonical transformation that shows directly that the SCB is composed of two Floreanini-Jackiw's particles with the same chirality which spectrum is a vacuum-like one. As another conflictive result we have proved that a Wess-Zumino term used in the literature consists of the scalar field, once again denying the assertion that the WZ term adds a new degree of freedom to the SCB theory in order to modify the physics of the system.Comment: 6 pages, Revtex. Final version to appear in Physical Review

Optimization of a high work function solution processed vanadium oxide hole-extracting layer for small molecule and polymer organic photovoltaic cells

We report a method of fabricating a high work function, solution processable vanadium oxide (V2Ox(sol)) hole-extracting layer. The atmospheric processing conditions of film preparation have a critical influence on the electronic structure and stoichiometry of the V2Ox(sol), with a direct impact on organic photovoltaic (OPV) cell performance. Combined Kelvin probe (KP) and ultraviolet photoemission spectroscopy (UPS) measurements reveal a high work function, n-type character for the thin films, analogous to previously reported thermally evaporated transition metal oxides. Additional states within the band gap of V2Ox(sol) are observed in the UPS spectra and are demonstrated using X-ray photoelectron spectroscopy (XPS) to be due to the substoichiometric nature of V2Ox(sol). The optimized V2Ox(sol) layer performance is compared directly to bare indium–tin oxide (ITO), poly(ethyleneoxythiophene):poly(styrenesulfonate) (PEDOT:PSS), and thermally evaporated molybdenum oxide (MoOx) interfaces in both small molecule/fullerene and polymer/fullerene structures. OPV cells incorporating V2Ox(sol) are reported to achieve favorable initial cell performance and cell stability attributes

Chiral bosons and improper constraints

We argue that a consistent quantization of the Floreanini-Jackiw model, as a constrained system, should start by recognizing the improper nature of the constraints. Then each boundary conditon defines a problem which must be treated sparately. The model is settled on a compact domain which allows for a discrete formulation of the dynamics; thus, avoiding the mixing of local with collective coordinates. For periodic boundary conditions the model turns out to be a gauge theory whose gauge invariant sector contains only chiral excitations. For antiperiodoc boundary conditions, the mode is a second-class theory where the excitations are also chiral. In both cases, the equal-time algebra of the quantum energy-momentum densities is a Virasoro algebra. The Poincar\'e symmetry holds for the finite as well as for the infinite domain.Comment: 13 pages, Revtex file, IF.UFRGS Preprin

Light-Front Quantum Chromodynamics: A framework for the analysis of hadron physics

White Paper of International Light Cone Advisory CommitteeAn outstanding goal of physics is to find solutions that describe hadrons in the theory of strong interactions, Quantum Chromodynamics (QCD). For this goal, the light-front Hamiltonian formulation of QCD (LFQCD) is a complementary approach to the well-established lattice gauge method. LFQCD offers access to the hadrons' nonperturbative quark and gluon amplitudes, which are directly testable in experiments at existing and future facilities. We present an overview of the promises and challenges of LFQCD in the context of unsolved issues in QCD that require broadened and accelerated investigation. We identify specific goals of this approach and address its quantifiable uncertainties