Constitutive Models Based on Compressible Plastic Flows

The need for describing materials under time or cycle dependent loading conditions has been emphasized in recent years by several investigators. In response to the need, various constitutive models describing the nonlinear behavior of materials under creep, fatigue, or other complex loading conditions were developed. The developed models for describing the fully dense (non-porous) materials were mostly based on uncoupled plasticity theory. The improved characterization of materials provides a better understanding of the structual response under complex loading conditions. The pesent studies demonstrate that the rate or time dependency of the response of a porous aggregate can be incorporated into the nonlinear constitutive behavior of a porous solid by appropriately modeling the incompressible matrix behavior. It is also sown that the yield function which wads determined by a continuum mechanics approach must be verified by appropriate experiments on void containing sintered materials in order to obtain meaningful numbers for the constants that appear in the yield function

Assessment of Mitral Valve Resistance Index by Echocardiography in Mitral Stenosis Before and After Balloon Mitral Valvotomy and Its Hemodynamic Implications

INTRODUCTION: Valvular stenosis is common cardiac disease with greater morbidity and mortality especially in developing countries like India. Echocardiography is considered as an important and simple tool to evaluate valve stenosis .Almost all cases of mitral stenosis are due to rheumatic heart disease. Assessment of severity of mitral stenosis by echocardiography utilizes many parameters using 2D echo, M mode, and Doppler methods. Conventional methods include mitral valve orifice area determination by planimetry and pressure half time method, pressure gradient determinations with Bernoulli’s equation, and mitral leaflet separation index. But the common problem that occurs in all these measurements is that, only anatomic information alone is provided to the clinician. In most of the situations, clinical decisions are made by assessing the functional or hemodynamic status of the valve lesions irrespective of the choice of management. This fact is further strengthened by many observations that, for given mitral valve orifice area, different hemodynamic profiles found to be present. Hence therapeutic judgments have to be contemplated based on functional or hemodynamic status of the patients. AIM OF THE STUDY: 1. To assess mitral valve resistance index in mitral stenosis by echocardiography before and after balloon mitral valvotomy. 2. To study the relationship between systolic pulmonary artery pressure and mitral valve resistance both before and after percutaneous mitral commissurotomy. 3. To study the correlation between severity of mitral stenosis and mitral valve resistance. METHODOLOGY: STUDY DESIGN: This study has been confirmed by the Ethic Committee of Madras medical college, Tamilnadu Dr MGR medical University and all the participants were informed of its objectives before the study and signed a letter of consent in accordance with the Helsinki Declaration Standards. PATIENTS PROFILE: This is a prospective cohort study. During a period of 6 months, 20 patients with pure Mitral Stenosis who were referred and eligible for percutaneous commissurotomy of mitral valve who agreed to undergo 2D and Doppler echocardiographic examination. It was made sure that they have an adequate tricuspid regurgitant jet for systolic PAP calculation was detectable both before and after valvotomy, were prospectively recruited in this study. INCLUSION CRITERIA: 1. Patients with symptomatic rheumatic mitral stenosis undergoing balloon mitral valvotomy. 2. Adequate tricuspid regurgitation jet. EXCLUSION CRITERIA: 1. LA thrombus, 2. More than mild MR, AS, AR and pulmonary stenosis, 3. CAD requiring surgical revascularization, 4. Poor echocardiographic window, 5. Critically ill patients, 6. Organic tricuspid valvular disesase. 5CONCLUSIONS: 1. Mitral valve resistance index is a strong and independent predictor of systolic pulmonary artery pressure both before and after percutaneous balloon mitral valvotomy in mitral stenosis patients. 2. Mitral valve resistance also correlates with severity of mitral stenosis in our study. 3. Because of inherent limitations of conventional echocardiographic parameters in evaluation of MS, valve resistance can be an adjunct tool in assessment of severity. 4. In our study, among conventional indices, trans mitral mean gradient better correlates with hemodynamic status than mitral valve area

Matter wave switching in Bose-Einstein condensates via intensity redistribution soliton interactions

Using time dependent nonlinear (s-wave scattering length) coupling between the components of a weakly interacting two component Bose-Einstein condensate (BEC), we show the possibility of matter wave switching (fraction of atoms transfer) between the components via shape changing/intensity redistribution (matter redistribution) soliton interactions. We investigate the exact bright-bright N-soliton solution of an effective one-dimensional (1D) two component BEC by suitably tailoring the trap potential, atomic scattering length and atom gain or loss. In particular, we show that the effective 1D coupled Gross-Pitaevskii (GP) equations with time dependent parameters can be transformed into the well known completely integrable Manakov model described by coupled nonlinear Schr\"odinger (CNLS) equations by effecting a change of variables of the coordinates and the wave functions under certain conditions related to the time dependent parameters. We obtain the one-soliton solution and demonstrate the shape changing/matter redistribution interactions of two and three soliton solutions for the time independent expulsive harmonic trap potential, periodically modulated harmonic trap potential and kink-like modulated harmonic trap potential. The standard elastic collision of solitons occur only for a specific choice of soliton parameters.Comment: 11 pages, 14 figures, 1 tabl

Bridge Correlational Neural Networks for Multilingual Multimodal Representation Learning

Recently there has been a lot of interest in learning common representations for multiple views of data. Typically, such common representations are learned using a parallel corpus between the two views (say, 1M images and their English captions). In this work, we address a real-world scenario where no direct parallel data is available between two views of interest (say, $V_1$ and $V_2$) but parallel data is available between each of these views and a pivot view ($V_3$). We propose a model for learning a common representation for $V_1$, $V_2$ and $V_3$ using only the parallel data available between $V_1V_3$ and $V_2V_3$. The proposed model is generic and even works when there are $n$ views of interest and only one pivot view which acts as a bridge between them. There are two specific downstream applications that we focus on (i) transfer learning between languages $L_1$,$L_2$,...,$L_n$ using a pivot language $L$ and (ii) cross modal access between images and a language $L_1$ using a pivot language $L_2$. Our model achieves state-of-the-art performance in multilingual document classification on the publicly available multilingual TED corpus and promising results in multilingual multimodal retrieval on a new dataset created and released as a part of this work.Comment: Published at NAACL-HLT 201

A Correlational Encoder Decoder Architecture for Pivot Based Sequence Generation

Interlingua based Machine Translation (MT) aims to encode multiple languages into a common linguistic representation and then decode sentences in multiple target languages from this representation. In this work we explore this idea in the context of neural encoder decoder architectures, albeit on a smaller scale and without MT as the end goal. Specifically, we consider the case of three languages or modalities X, Z and Y wherein we are interested in generating sequences in Y starting from information available in X. However, there is no parallel training data available between X and Y but, training data is available between X & Z and Z & Y (as is often the case in many real world applications). Z thus acts as a pivot/bridge. An obvious solution, which is perhaps less elegant but works very well in practice is to train a two stage model which first converts from X to Z and then from Z to Y. Instead we explore an interlingua inspired solution which jointly learns to do the following (i) encode X and Z to a common representation and (ii) decode Y from this common representation. We evaluate our model on two tasks: (i) bridge transliteration and (ii) bridge captioning. We report promising results in both these applications and believe that this is a right step towards truly interlingua inspired encoder decoder architectures.Comment: 10 page

Man-power needs for marine fisheries by 2000 AD

Formal training of operatives for marine fishing industry started in late forties when the erstwhile Deep Sea Fishing Station commenced training activities. However, organised training for fisheries personnel commenced with the establishment of CIFNET (erstwhile CIFO) and CIFE in the early sixties. The former catered to the manpower needs for operating the fishing vessels while the latter produced the managerial/administrative personnel for shore support. Today a number of fishery colleges and Agricultural colleges supplement the training activities of these two training establishments in fisheries-related disciplines. Accent on innovations of harvest and post harvest technologies of marine capture fisheries has necessitated upgradation and modernisation of training processes of CIFNET. This has been done following a series of studies and evaluations commensurate with the type and kind of technologies, breed and nature of craft and gear Introduced etc. In addition to meeting the domestic needs, the trained manpower is the national wealth which is spared (or development of industry in friendly developing countries to our advantage due to the inflow of foreign exchange. Reckoning the present pace of growth of our marine fishing Industry a projection of the manpower needs for 2000 AD Is attempted In the present paper. The nature and specialities of the human resources that would be needed that time have t)een attempted to be Identified and the innovation to be made in the production process are outlined

Change in the room temperature magnetic property of ZnO upon Mn doping

We present in this paper the changes in the room temperature magnetic property of ZnO on Mn doping prepared using solvo-thermal process. The zero field cooled (ZFC) and field cooled (FC) magnetisation of undoped ZnO showed bifurcation and magnetic hysteresis at room temperature. Upon Mn doping the magnetic hysteresis at room temperature and the bifurcation in ZFC-FC magnetization vanishes. The results seem to indicate that undoped ZnO is ferromagnetic while on the other hand the Mn doped ZnO is not a ferromagnetic system. We observe that on addition of Mn atoms the system shows antiferromagnetism with very giant magnetic moments.Comment: 5 figure