Levy statistical fluctuations from a Random Amplifying Medium

We report the studies of emission from a novel random amplifying medium that we term a ``Levy Laser'' due to the non-Gaussian statistical nature of its emission over the ensemble of random realizations. It is observed that the amplification is dominated by certain improbable events that are ``larger than rare'', which give the intensity statistics a Levy like ``fat tail''. This, to the best of our knowledge, provides the first experimental realization of Levy flight in optics in a random amplifying medium.Comment: 22 pages, 14 figures (postscript format

Automatic classification of MR brain tumor images using KNN, ANN, SVM and CNN

A brain tumor classification system has been designed and developed. This work presents a new approach to the automated classification of astrocytoma, medulloblastoma, glioma, glioblastoma multiforme and craniopharyngioma type of brain tumors based on first order statistics and gray level co-occurrence matrix, in magnetic resonance images. The magnetic resonance feature image used for the tumor detection consists of T2-weighted magnetic resonance images for each axial slice through the head. To remove the unwanted noises in the magnetic resonance image, median filtering is used. First order statistics and gray level co-occurrence matrix-based features are extracted. Finally, k-nearest neighbor, artificial neural network, support vector machine and convolutional neural networks are used to classify the brain tumor images. The application of the proposed method for tracking tumor is demon­strated to help pathologists distinguish its type of tumor. A classification with an accuracy of 89%, 90%, 91% and 95% has been obtained by, k-nearest neighbor, artificial neural network, support vector machine and convolutional neural networks

Enhancing Learning Technology: By Incorporating Social Media Platforms in Language Teaching Classrooms

Social Media performs a high-surpassed position in English, as it allows English language beginners to improve their studying and writing abilities. Social media is utilized in classrooms, wherever students can begin their blogs. They will make their connections with humans more prominent and construct a social community known as PLN (Personal Learning Network). Throughout COVID-19, all social media networks became popular, and plenty of used sites for an off-the-cuff time-pass. With the assistance of web 2.0 technology, blogs became treasured and engaging equipment for English and Foreign Languages, teachers the scope of these social networks, significantly blogs, thus, will broaden the learner-learner and learner-teacher interactions. The researcher will analyze the difficulties of EFL learners and suggest technical remedies to eliminate the problem and face barriers in writing English via educational technology

Observation of narrow fluorescence from doubly driven four-level atoms at room temperature

Unusually narrow fluorescence peaks are seen from Rubidium-85 atoms under the action of two driving laser fields that are in a three dimensional molasses configuration. One of the lasers is held at a fixed detuning from the "cooling" transition, while the other is scanned across the "repumping" transitions. The fluorescence peaks are split into symmetric pairs, with the seperation within a pair increasing with the detuning of the cooling laser. For large detunings additional small peaks are seen. A simple model is proposed to explain these experimental observations.Comment: 8 pages, 4 figures, needs epl.cl

Light scattering from a magnetically tunable dense random medium with weak dissipation : ferrofluid

We present a semi-phenomenological treatment of light transmission through and its reflection from a ferrofluid, which we regard as a magnetically tunable system of dense random dielectric scatterers with weak dissipation. Partial spatial ordering is introduced by the application of a transverse magnetic field that superimposes a periodic modulation on the dielectric randomess. This introduces Bragg scattering which effectively enhances the scattering due to disorder alone, and thus reduces the elastic mean free path towards Anderson localization. Our theoretical treatment, based on invariant imbedding, gives a simultaneous decrease of transmission and reflection without change of incident linear polarisation as the spatial order is tuned magnetically to the Bragg condition, namely the light wave vector being equal to half the Bragg vector (Q). Our experimental observations are in qualitative agreement with these results. We have also given expressions for the transit (sojourn) time of light and for the light energy stored in the random medium under steady illumination. The ferrofluid thus provides an interesting physical realization of effectively a "Lossy Anderson-Bragg" (LAB) cavity with which to study the effect of the interplay of spatial disorder, partial order and weak dissipation on light transport. Given the current interest in propagation, optical limiting and storage of light in ferrofluids, the present work seems topical

A prospective, comparative, observational study of quality of spinal anaesthesia with 0.5% and 0.75% plain isobaric ropivacaine in lower abdomen and lower limb surgeries

Background: Spinal anaesthesia or subarachnoid block remains one of the basic techniques in the arsenal of modern anaesthesiology. Aim of the study was to evaluate and compare quality of spinal anaesthesia with isobaric 0.5% and 0.75% intrathecal ropivacaine in patients undergoing lower abdominal and lower limb surgeries.Methods: 100 patients between 18 and 60 years, of either gender belonging to ASA class I or II, posted for elective lower abdominal and lower limb surgeries, planned under spinal anaesthesia using ropivacaine. Patients were grouped as group A: 3 ml (15 mg) of 0.5% plain ropivacaine and Group B: 3ml (22.5mg) of 0.75% plain ropivacaine. Parameters observed were onset and duration of sensory and motor block, maximum sensory level achieved degree of motor blockade, two segment regression, and haemodynamic changes.Results: No significant differences were noted in Mean time for onset and time to achieve maximum level of sensory and motor blockade in both groups. Maximal dermatomal level was T10 in group A and T8 in group B which was statistically significant. Also, 96% patients had grade III motor blockade in group B as compared to 80% in group A which was statistically significant. Significant differences were noted in Time for two segment regression (92.56±11.846 minutes in group A and 137.3±13.06 min in group B), the duration of sensory blockade (184.5±18.385 min in group A and 238.8±19.260 min in group B) and duration of motor blockade (120.3±15.59 min in group A and 178.8±16.053 min in group B).Conclusions: Intrathecal isobaric ropivacaine 0.5% and 0.75% are safe and effective with minimal intraoperative and postoperative side effects. Recommended for short duration orthopaedic and lower abdominal surgeries where prolonged motor blockade is undesirable.  

A prospective observational study of adverse drug reactions to antiretroviral therapy: type and risk factors in a tertiary care teaching hospital

Background: To collect demographic details of patients receiving antiretroviral therapy (ART) and study type of adverse drug reactions (ADRs) and risk factors for ADRs to ART and to assess causality, severity, and preventability assessment of the reported ADRs.Methods: A prospective observational study was conducted for 6 months from January 2012 until June 2012 at ART Center, KR Hospital of Mysore Medical College & Research Institute, Mysore. Data were evaluated for patient demography, risk factors for ADRs, type of ADRs. ADRs were also assessed for their causality, severity, and preventability as per the standard algorithm, using SPSS for windows (version 16.0).Results: Out of 158 patients evaluated, majority were of age group of 21-40 years (66.5%). More number of illiterate patients (55.7%) showed ADRs to ART. Most patients were of CD4 count <250 cells/μl (65.82%). Most common regimen which caused ADRs was zidovudine + lamivudine + nevirapine. Most common type of ADRs was anemia (55.06%) and rash (25.31%). On evaluation of the causality of ADRs, majority were found to be possible (89.24%). The severity assessment showed that most of the patients ADRs were of level 3 (93.05%). The preventability assessment showed that 30.38% patients ADRs were preventable.Conclusion: Identifying risk factors are of crucial importance to optimize the initial choice of ARVs regimen before initiating therapy and to prevent severity and complications caused by ART, thereby improving the quality of care to patients on ART

A study of drug utilisation pattern in patients of chronic kidney disease at a tertiary care hospital

Background: Chronic kidney disease (CKD) is a major public health issue and widely prevalent non-communicable disease in India. CKD has a complex pharmacotherapy and it inevitably requires poly-pharmacy. CKD patients require to take medications for a lifelong period, which makes it very important to study the prescribing trends on a regular basis. The main objective of the study was to analyse current prescribing trends in the management of CKD patients and to know whether the prescribing rationality was maintained.Methods: After Institutional Ethics Committee approval, a prospective         Cross-sectional study was carried out at Nephrology department of a tertiary care hospital for a period of six months from 1st June 2017 to 30th November 2017. Patients diagnosed with CKD by treating Nephrologist were included and their prescriptions were analysed to study the prescribing patterns.Results: A total of 120 cases were analysed during the study, of which 81.7% were males and 18.3% were females. Analysis of WHO core drug prescribing indicators showed that the average number of drugs prescribed per patient was 5.13, percentage of drugs prescribed by generic name was 30.03%, percentage of patients with an injection prescribed was 16.6%, percentage of drugs prescribed from essential medicine list was 65.8% and percentage of patients prescribed with an antibiotic was 10.8%. Antihypertensive drugs (39.9%) were the most commonly used drugs, followed by, calcium salts (12.01%), multi-vitamins (7.6%), oral iron supplements (6.8%), erythropoietin (6.3%) and ulcer protectives (6.1%).Conclusions: Maximum number of drugs were prescribed from cardiovascular class of drugs. Calcium channel blockers and diuretics were the commonest group of antihypertensives prescribed. The principle of rational prescribing was followed