Arithmetic Circuits and the Hadamard Product of Polynomials

Motivated by the Hadamard product of matrices we define the Hadamard product of multivariate polynomials and study its arithmetic circuit and branching program complexity. We also give applications and connections to polynomial identity testing. Our main results are the following. 1. We show that noncommutative polynomial identity testing for algebraic branching programs over rationals is complete for the logspace counting class \ceql, and over fields of characteristic $p$ the problem is in \ModpL/\Poly. 2.We show an exponential lower bound for expressing the Raz-Yehudayoff polynomial as the Hadamard product of two monotone multilinear polynomials. In contrast the Permanent can be expressed as the Hadamard product of two monotone multilinear formulas of quadratic size.Comment: 20 page

Magnetocaloric effect in Gd/W thin film heterostructures

In an effort to understand the impact of nanostructuring on the magnetocaloric effect, we have grown and studied gadolinium in MgO/W(50 $\textrm{\AA}$)/[Gd(400 $\textrm{\AA}$)/W(50 $\textrm{\AA}$)]$_8$ heterostructures. The entropy change associated with the second order magnetic phase transition was determined from the isothermal magnetization for numerous temperatures and the appropriate Maxwell relation. The entropy change peaks at a temperature of 284 K with a value of approximately 3.4 J/kg-K for a 0-30 kOe field change; the full width at half max of the entropy change peak is about 70 K, which is significantly wider than that of bulk Gd under similar conditions. The relative cooling power of this nanoscale system is about 240 J/kg, somewhat lower than that of bulk Gd (410 J/kg). An iterative Kovel-Fisher method was used to determine the critical exponents governing the phase transition to be $\beta=0.51$, and $\gamma=1.75$. Along with a suppressed Curie temperature relative to the bulk, the fact that the convergent value of $\gamma$ is that predicted by the 2-D Ising model may suggest that finite size effects play an important role in this system. Together, these observations suggest that nanostructuring may be a promising route to tailoring the magnetocaloric response of materials

Recycling of tungsten based heavy alloy scrap

The recovery of tungsten from heavy alloy scrap has been explored oxidation of tungsten heavy alloy using oxygen and its subsequent reduction with hydrogen was studied. The oxidation behaviour of the scrap was investigated by simultaneous TG/DTA. Oxidation studies showed a weight gain of 26% and the enthalpy of oxidation was found to be -625 kJ/mol of tungsten. The X-ray diffraction of the oxidised powder has shown the formation of WO3, Fe2WO6 and NiWO4 phases. The reduction of the oxidized material in hydrogen atmosphere at 1000 C yielded a pure tungsten phase in powder form with an approximate weight loss of 25%

Thermal expansion of doped lanthanum gallates

Thermal expansion of several compositions of Sr and Mg-doped LaGaO3 including an A-site deficient composition (La0.9Sr0.1)0.98(Ga0.8Mg0.2)O2.821 were measured in the temperature range from 298 to 1273 K. The effect of doping on thermal expansion was studied by varying the composition at one site of the perovskite structure (either A or B), while keeping the composition at the other site invariant. Thermal expansion varied nonlinearly with temperature and exhibited an inflexion between 550 and 620 K, probably related to the change in crystal structure from orthorhombic to rhombohedral. The dependence of average thermal expansion coefficient (α av) on the dopant concentration on either A or B site of the perovskite structure was found to be linear, when the composition at the other site was kept constant. Mg doping on the B-site had a greater effect on the average thermal expansion coefficient than Sr doping on the A-site. Cation deficiency at the A-site decreases thermal expansion when compositions at both sites are held constant

Knowledge, attitude, practice of rational use of medicines among junior residents in a tertiary care hospital

Background: Irrational use of prescribing is on the rise due to many factors like false beliefs, following a prescribing pattern of senior doctors, inadequate knowledge, ignorance, promotional activities for the profit of professionals by pharmaceutical industry and lack of enforcement of regulations by regulatory authorities. Junior residents are exposed to variety of prescribing patterns in the first year and are the future physicians and specialists. There are very few studies among JRs, hence the present study was conducted to assess the knowledge, attitude and practice of junior residents about rational use of medicines.Methods: This was a cross-sectional, questionnaire based study conducted among JRs at a tertiary care hospital in South India in June 2015. The participants were explained about the study and consent was taken. Permission was obtained from institutional ethics committee. Identity of the residents was kept confidential. A self-developed, pre-validated, semi-structured questionnaire consisting of both open-ended and closed-ended items was used. Questionnaire was designed to obtain information about the knowledge, attitude and practice of RUM. The data was recorded and analyzed using Microsoft Excel (2013 version) and the results are explained in frequency and percentage.Results: The knowledge related to essential medicines list (EML), P drugs and schedule H drugs was limited. Participants had limited knowledge about the revision of EML list, number of fixed dose combinations (FDCs)in EML, STEP criteria for choosing a P drug and advantages of choosing a P drug Most of the JRs frequently prescribed drugs from EML. Trade name and newer drugs were prescribed around 50%. The prescription of FDCs from EML was very low (6%). Around 50% of JRs prescribe medicines with both generic and brand name.Conclusions: Majority of JRs were aware about various issues concerned with RUM but the knowledge related to EML, P drugs, schedule H drugs and number of FDCs in EML was limited.  As junior residents are future prescribers, they need to be aware of all the aspects of RUM. Inadequate/improper knowledge in the above areas is a matter of concern and needs to be addressed