Probing the deviation from maximal mixing of atmospheric neutrinos

Pioneering atmospheric muon neutrino experiments have demonstrated the near-maximal magnitude of the flavor mixing angle $\theta_{23}$. But the precise value of the deviation $D \equiv 1/2 - \sin^2 \theta_{23}$ from maximality (if nonzero) needs to be known, being of great interest -- especially to builders of neutrino mass and mixing models. We quantitatively investigate in a three generation framework the feasibility of determining $D$ in a statistically significant manner from studies of the atmospheric $\nu_\mu,\bar\nu_\mu$ survival probability including both vacuum oscillations and matter effects. We show how this determination will be sharpened by considering the up-down ratios of observed $\nu_\mu$- and $\bar\nu_\mu$-induced events and the differences of these ratios in specified energy and zenith angle bins. We consider 1 Megaton year of exposure to a magnetized iron calorimeter such as the proposed INO detector ICAL, taking into account both energy and zenith angle resolution functions. The sensitivity of such an exposure and the dependence of the determination of $D$ on the concerned oscillation parameters are discussed in detail. The vital use of matter effects in fixing the octant of $\theta_{23}$ is highlighted.Comment: Version to appear in PR

Non-classical photon pair generation in atomic vapours

A scheme for the generation of non-classical pairs of photons in atomic vapours is proposed. The scheme exploits the fact that the cross correlation of the emission of photons from the extreme transitions of a four-level cascade system shows anti-bunching which has not been reported earlier and which is unlike the case of the three level cascade emission which shows bunching. The Cauchy-Schwarz inequality which is the ratio of cross-correlation to the auto correlation function in this case is estimated to be $10^3-10^6$ for controllable time delay, and is one to four orders of magnitude larger compared to previous experiments. The choice of Doppler free geometry in addition to the fact that at three photon resonance the excitation/deexcitation processes occur in a very narrow frequency band, ensures cleaner signals.Comment: 18 pages, 7 figure

A STUDY ON MECHANICAL PROPERTIES OF CEMENT CONCRETE BY PARTIAL REPLACEMENT OF FINE AGGREGATES WITH BOTTOM ASH

Bottom Ash is a new waste material and abundantly available. It is a solid residue which falls into furnace bottom in modern large thermal power plants and constitutes about 20% of total ash content of the coal fed in the boilers. Direct use of this material with a large quantity, will provide a solution to dispose of this material, and the possibility as alternative materials in construction. The main objective of this research is to study the behavior of concrete mix which comprises of partial replacement of fine aggregates with bottom ash against plain concrete. The study was carried out using coal bottom ash as a partial replacement with fine aggregates in the concrete mix by 20%, 30%, 40%, and 50% by weight. The various strength properties studied consist of compressive strength, flexural strength and splitting tensile strength. The results shows that the compressive strength, split tensile strength and flexural strength decreased as the percentage of replacement of bottom ash increased as compared to plain concrete. It was observed that up to 20% replacement the results of compressive test, flexural test and split tensile test are approximately same as that of the controlled concrete

Trial of ORG 10172 in acute stroke treatment classification and associated risk factors of ischemic stroke: a prospective study from a tertiary care center in South India

Background: Stroke is the leading cause of acquired disability worldwide. Better understanding of risk factors helps to reduce the community burden of stroke. Aim of the study was to determine pattern of ischemic stroke subtype and associated risk factors.Methods: Of 220 patients with first ever stroke, 168 patients of ischemic stroke were enrolled prospectively from January 2016 to May 2016 at ESIC Superspeciality hospital, Hyderabad. Patients were categorized in accordance with the Trial of Org 10172 in Acute Stroke treatment (TOAST) criteria.Results: Of 168 patients, 110 (65.4%) were males; male to female ratio was 1.8:1. The mean age was 53.912.3 years. Small vessel occlusion (SVO) occurred in younger age group as compared to other stroke subtypes. Frequency of large-artery atherosclerosis (LAA) (46.4%) was highest (Extracranial: 41.1%, intracranial: 36.9%), followed by SVO (32.4%), cardio embolism (15.4%), undetermined (4.7%) and other determined causes (1.1%). Risk factors included dyslipidemia (79%), hypertension (67.8%), smoking (58.3%), alcohol use (54.7%), diabetes (40.4%) and physical inactivity (27.3%). Common association observed was smoking (P - 0.004) and alcohol (P - 0.003) with LAA and SVO, and dilated cardiomyopathy with cardio embolism.Conclusions: LAA was observed frequently than SVO. Frequency of SVO was lower than Asian but higher than western, while cardio embolism was lower than Western and similar to Asian stroke studies. Dyslipidemia was the predominant risk factor than hypertension reported from Asian and Western stroke registry. This unique pattern can be attributed to differences in demographic and risk factor profiles. The study confirms the need for vigorous primary and secondary prevention measures targeting modifiable risk factors of stroke