Robust pre-processing techniques for non-ideal iris images

The human iris has been demonstrated to be a very accurate, non-invasive and easy-to-use biometric for personal identification. Most of the current state-of-the-art iris recognition systems require the iris acquisition to be ideal. A lot of constraints are hence put on the user and the acquisition process.;Our aim in this research is to relax these conditions and to develop a pre-processing algorithm, which can be used in conjunction with any matching algorithm to handle the so-called non-ideal iris images. In this thesis we present a few robust techniques to process the non-ideal iris images so as to give a segmented iris image to the matching algorithm. The motivation behind this work is to reduce the false reject rates of the current recognition systems and to reduce the intra-class variability. A new technique for estimating and compensating the angle in non-frontal iris images is presented. We have also developed a novel segmentation algorithm, which uses an ellipse-fitting approach for localizing the pupil. A fast and simple limbus boundary segmentation algorithm is also presented

Importance of initial conditions in the polarization of complex networks

Currently used models of opinion formation use random initial conditions. In reality, most people in a social network, except for a small fraction of the population, are initially either unaware of, or indifferent to, the disputed issue. To explore the consequences of such specific initial conditions, we study the polarization of social networks when conflicting ideas arise on two different seed nodes and then spread according to a majority rule. Using the configuration model and the stochastic block model as examples, we show that this framework leads to substantially different outcomes than those which employ random initial conditions. Moreover, the empirically observed splits in the karate and the dolphins' networks naturally come out of this paradigm. Our work thus suggests that the existing opinion dynamics models should be reevaluated to incorporate the initial condition dependence.Comment: Removed 1 figure, the final versio

Assessment of comorbidities in patients with deranged thyroid hormone levels

Background: There is association of deranged thyroid hormone levels with various co-morbidities. Drugs for comorbidity may interact with each other and affect the outcome of treatment. So, this study was planned to find out comorbidities with deranged thyroid hormone levels and various possible drug interactions.Methods: It was a prospective, observational study carried out at tertiary care hospital from November 2017 to June 2018. Thyroid hormonal levels reports were followed in OPD and online information system facility. Drugs interactions were checked by referring standard pharmacology textbooks, review articles and Medscape drug interaction checker. Approval from the Institutional Ethics Committee was taken before initiation of the study. Patients with deranged thyroid hormone levels were included in the study.Results: Study was conducted in 111 patients of thyroid disorders. Spondylitis, asthma, acne cases were seen in hypothyroid patients whereas hypokalemic periodic paralysis, thyroid ophthalmopathy statistically significantly seen in hyperthyroid patients. Various concurrent medications such as calcium, carbamazepine decreases the effects of levothyroxine. For management of comorbidities various drugs are given which also interact among themselves significantly.Conclusions: Diabetes mellites, obesity, spondylitis, lichen planus were more common in hypothyroidism while comorbidities like hypertension, hypokalemic periodic paralysis, thyroid ophthalmopathy were found to be more in hyperthyroidism.  Incidence of drug interactions is found to be more with increased use of medications for comorbidities, so physicians should be careful while prescribing them. Due to drug interactions desired effects of drugs given for thyroid disorders may not be observed

Efficacy of selection in sexually breeding Artemia (Artemia franciscana, Kellogg, 1906)

Bi-directional selection for smaller naupliar size (SNS) and bigger naupliar size (BNS) was practiced to develop two divergent lines. The e⁄cacy of bidirectional mass selection in Artemia franciscana was evaluated by comparing the predicted genetic gains with the realized genetic gains. Two sets of predictions were made using two heritability estimates, e.g., the heritability estimate from full-sib analysis (h2) and the estimate from regression of o¡spring on mid parent (bop). Predictions with the full-sib heritabilities were of very high magnitude as compared with predictions with bop heritabilities

Spherical gravitational collapse: tangential pressure and related equations of state

We derive an equation for the acceleration of a fluid element in the spherical gravitational collapse of a bounded compact object made up of an imperfect fluid. We show that non-singular as well as singular solutions arise in the collapse of a fluid initially at rest and having only a tangential pressure. We obtain an exact solution of Einstein equations, in the form of an infinite series, for collapse under tangential pressure with a linear equation of state. We show that if a singularity forms in the tangential pressure model, the conditions for the singularity to be naked are exactly the same as in the model of dust collapse.Comment: Latex, 26 page

Phenotypic estimates and heritability values of Artemia franciscana

Artemia, in all stages of its life cycle, is suitable food for most diversi¢ed groups of aquatic animals. Although its size at different stages restricts its use as a food for some groups of ¢sh, this problem can be overcome using selective breeding techniques. The formulation of any selective breeding programme calls for a proper understanding of the genetic architecture of the economically important traits of the population under study. Thus, heritability for certain important life history and reproductive traits was estimated in Artemia franciscana from the Great Salt Lake, Utah. In the present study, the sexwise heritability values for growth and reproduction traits were estimated using parent offspring regression. The phenotypic parameters for the same traits are also recorded. The naupliar length was 487.072.0 and 490.671.8 mm for males and females, respectively, whereas the heritability values for naupliar length were 0.585170.2153 and 0.376670.1899 respectively. The length at 3 and 6 days of age were 1.8770.03 and 4.1070.08mm, respectively, for maleswhereas1.8770.03 and 4.3070.08mm, respectively, for females.The heritability values for length at 3 and 6 days of age for males were 0.327270.3651 and 0.496570.2466, respectively, whereas the respective values for the females were 0.116770.3841 and 0.022270.2971. The estimates of length at ¢rst brood, pre-reproductive period and number of o¡- spring in ¢rst brood were 10.0970.23mm, 16.007 0.23 days and 53.5771.37 days, respectively, whereas the heritability values for respective traits were 0.040370.1078,0.323470.2874 and 0.340470.2202

Gravitational Collapse, Black Holes and Naked Singularities

This article gives an elementary review of gravitational collapse and the cosmic censorship hypothesis. Known models of collapse resulting in the formation of black holes and naked singularities are summarized. These models, when taken together, suggest that the censorship hypothesis may not hold in classical general relativity. The nature of the quantum processes that take place near a naked singularity, and their possible implication for observations, is briefly discussed.Comment: 17 pages, Latex File. Based on a talk given at the Discussion Workshop on Black Holes, Bangalore, 9-12 Dec. 1997, to appear in the Conference Proceeding

A pharmacoeconomic study of different brands of commonly prescribed antihypertensive drugs

Background: The hypertension is the most common chronic disease, therefore treatment should be affordable. The antihypertensive drugs of same strength are available in market at different costs. This study was undertaken to create awareness among health care workers and patients, about cost difference among different brands of same antihypertensive drug. So that whenever possible, a cheaper effective brand can be prescribed to ensure better patient adherence.Methods: Maximum retail price (MRP) of various antihypertensive drugs of same strength, manufactured by different pharmaceutical companies was obtained from various offline and online sources. The minimum and maximum cost of 10 tablets/capsules noted. The cost ratio and percentage cost variation was calculated for single drug and fixed dose combinations. The ceiling price (as per DPCO) of essential antihypertensives (as per national list of essential medicines) was compared with their maximum cost.Results: The formulations of single antihypertensive drugs (41) and fixed dose combinations of two drugs (19) and three drugs (9) were included in the study. Among the single antihypertensives analyzed the highest cost difference was of eplerenone (50 mg) and high cost ratio and cost variation percentage was of amlodipine (5 mg). Among fixed dose combination of two drugs analyzed highest cost difference was found that of hydrochlorothazide (12.5 mg)+olmesartan (40 mg) combination and highest cost ratio and percentage cost variation was of amlodipine (5 mg)+telmisartan (40 mg).Conclusions: There was a huge price variation among the antihypertensive drugs manufactured by various companies. Some measures must be taken by the government to bring the uniformity in the price that will help to reduce the economic burden on the patients

Reissner Nordstr\"{o}m Background Metric in Dynamical Co-ordinates: Exceptional Behaviour of Hadamard States

We cast the Reissner Nordstrom solution in a particular co-ordinate system which shows dynamical evolution from initial data. The initial data for the $E<M$ case is regular. This procedure enables us to treat the metric as a collapse to a singularity. It also implies that one may assume Wald axioms to be valid globally in the Cauchy development, especially when Hadamard states are chosen. We can thus compare the semiclassical behaviour with spherical dust case, looking upon the metric as well as state specific information as evolution from initial data. We first recover the divergence on the Cauchy horizon obtained earlier. We point out that the semiclassical domain extends right upto the Cauchy horizon. This is different from the spherical dust case where the quantum gravity domain sets in before. We also find that the backreaction is not negligible near the central singularity, unlike the dust case. Apart from these differences, the Reissner Nordstrom solution has a similarity with dust in that it is stable over a considerable period of time. The features appearing dust collapse mentioned above were suggested to be generally applicable within spherical symmetry. Reissner Nordstrom background (along with the quantum state) generated from initial data, is shown not to reproduce them

Learning with a Drifting Target Concept

We study the problem of learning in the presence of a drifting target concept. Specifically, we provide bounds on the error rate at a given time, given a learner with access to a history of independent samples labeled according to a target concept that can change on each round. One of our main contributions is a refinement of the best previous results for polynomial-time algorithms for the space of linear separators under a uniform distribution. We also provide general results for an algorithm capable of adapting to a variable rate of drift of the target concept. Some of the results also describe an active learning variant of this setting, and provide bounds on the number of queries for the labels of points in the sequence sufficient to obtain the stated bounds on the error rates