Shuffling a Stacked Deck: The Case for Partially Randomized Ranking of Search Engine Results

In-degree, PageRank, number of visits and other measures of Web page popularity significantly influence the ranking of search results by modern search engines. The assumption is that popularity is closely correlated with quality, a more elusive concept that is difficult to measure directly. Unfortunately, the correlation between popularity and quality is very weak for newly-created pages that have yet to receive many visits and/or in-links. Worse, since discovery of new content is largely done by querying search engines, and because users usually focus their attention on the top few results, newly-created but high-quality pages are effectively ``shut out,'' and it can take a very long time before they become popular. We propose a simple and elegant solution to this problem: the introduction of a controlled amount of randomness into search result ranking methods. Doing so offers new pages a chance to prove their worth, although clearly using too much randomness will degrade result quality and annul any benefits achieved. Hence there is a tradeoff between exploration to estimate the quality of new pages and exploitation of pages already known to be of high quality. We study this tradeoff both analytically and via simulation, in the context of an economic objective function based on aggregate result quality amortized over time. We show that a modest amount of randomness leads to improved search results

FORTRESS: FORTRAN programs for solving coupled Gross-Pitaevskii equations for spin-orbit coupled spin-1 Bose-Einstein condensate

Here, we present simple and efficient numerical scheme to study static and dynamic properties of spin-1 Bose-Einstein condensates (BECs) with spin-orbit (SO) coupling by solving three coupled Gross-Pitaevskii equations (CGPEs) in three-, quasi-two and quasi-one dimensional systems. We provide a set of three codes developed in FORTRAN 90/95 programming language with user defined '{\em option}' of imaginary and real-time propagation. We present the numerical results for energy, chemical potentials, and component densities for the ground state and compare with the available results from the literature. The results are presented for both the ferromagnetic and antiferromagnetic spin-1 BECs with and without SO coupling. To improve the computational speed, all the codes have the option of OpenMP parallelization. We have also presented the results for speedup and efficiency of OpenMP parallelization for the three codes with both imaginary and real-time propagation

Quantum phases and spectrum of collective modes in a spin-1 BEC with spin-orbital-angular-momentum coupling

Motivated by the recent experiments [Chen et al., Phys. Rev. Lett 121, 113204 (2018), Chen et al., Phys. Rev. Lett. 121, 250401 (2018)], we investigate the low-lying excitation spectrum of the ground-state phases of spin-orbital-angular-momentum-coupled (SOAM-coupled) spin-1 condensates.At vanishing detuning, a ferromagnetic SOAM-coupled spin-1 BEC can have two ground-state phases, namely coreless and polar-core vortex states, whereas an antiferromagnetic BEC supports only polar-core vortex solution. The angular momentum per particle, longitudinal magnetization, and excitation frequencies display discontinuities across the phase boundary between the coreless vortex and polar-core vortex phases. The low-lying excitation spectrum evaluated by solving the Bogoliubov-de-Gennes equations is marked by avoided crossings and hence the hybridization of the spin and density channels. The spectrum is further confirmed by the dynamical evolution of the ground state subjected to a perturbation suitable to excite a density or a spin mode and a variational analysis for the density-breathing mode

FORTRESS II: FORTRAN programs for solving coupled Gross-Pitaevskii equations for spin-orbit coupled spin-2 Bose-Einstein condensate

We provide here a set of three OpenMP parallelized FORTRAN 90/95 programs to compute the ground states and the dynamics of trapped spin-2 Bose-Einstein condensates (BECs) with anisotropic spin-orbit (SO) coupling by solving a set of five coupled Gross-Pitaevskii equations using a time-splitting Fourier spectral method. Depending on the nature of the problem, without any loss of generality, we have employed the Cartesian grid spanning either three-, two-, or one-dimensional space for numerical discretization. To illustrate the veracity of the package, wherever feasible, we have compared the numerical ground state solutions of the full mean-field model with those from the simplified scalar models. The two set of results show excellent agreement, in particular, through the equilibrium density profiles, energies and chemical potentials of the ground-states. We have also presented test results for OpenMP performance parameters like speedup and the efficiency of the three codes

Acute electrocardiographic changes during smoking: An observational study

Objective To study the temporal relationship of smoking with electrophysiological changes. Design Prospective observational study. Setting Tertiary cardiac center. Participants Male smokers with atypical chest pain were screened with a treadmill exercise test (TMT). A total of 31 such patients aged 49.8±10.5 years, in whom TMT was either negative or mildly positive were included. Heart rate variability (HRV) parameters of smokers were compared to those of 15 healthy non-smoking participants. Interventions All patients underwent a 24 h Holter monitoring to assess ECG changes during smoking periods. Results Heart rate increased acutely during smoking. Mean heart rate increased from 83.8±13.7 bpm 10 min before smoking, to 90.5±16.4 bpm during smoking, (p <0.0001) and returned to baseline after 30 min. Smoking was also associated with increased ectopic beats (mean of 5.3/h prior to smoking to 9.8/h during smoking to 11.3/h during the hour after smoking; p <0.001). Three patients (9.7%) had significant ST–T changes after smoking. HRV index significantly decreased in smokers (15.2±5.3) as compared to non-smoking controls participants (19.4±3.6; p=0.02), but the other spectral HRV parameters were comparable. Conclusions Heart rate and ectopic beats increase acutely following smoking. Ischaemic ST–T changes were also detected during smoking. Spectral parameters of HRV analysis of smokers remained in normal limits, but more importantly geometrical parameter—HRV index—showed significant abnormality

Design, synthesis and anticonvulsant activity of some new 6,8-halo-substituted-2H-[1,2,4]triazino[5,6-b]indole-3(5H)-one/-thione and 6,8-halo-substituted 5-methyl-2H-[1,2,4]triazino[5,6-b]indol-3(5H)-one/-thione

A new series of 6,8-halo-substituted-2H-[1,2,4]triazino[5,6-b]indole-3(5H)-one/-thione and 6,8-halo-substituted 5-methyl-2H-[1,2,4]triazino[5,6-b]indol-3(5H)-one/-thione (5a-5l) were designed and synthesized keeping in view of the structural requirement of pharmacophore. The above compounds were characterized by thin layer chromatography and spectral analysis. Anticonvulsant activity of the synthesized compounds was evaluated by the maximal electroshock (MES) test. Neurotoxicity and CNS depressant effects were evaluated by the rotarod motor impairment and Porsolt’s force swim tests, respectively. A computational study was carried out, for calculation of pharmacophore pattern, prediction of pharmacokinetic properties and toxicity properties. The above study revealed that the compounds 8-chloro-2H-[1,2,4]triazino[5,6-b]indol-3(5H)-one (5e), 6,8-dibromo-2H-[1,2,4]triazino[5,6-b]indol-3(5H)-one (5i) and 6,8-dibromo-5-methyl-2H-[1,2,4]triazino[5,6-b]indol-3(5H)-one (5k) possess excellent anticonvulsant activity in the series with little CNS depressant effect and no neurotoxicity as compared to standard drugs phenytoin and carbamazepine

Incidental gonadoblastoma in swyer syndrome: a case report with brief review of literature

Swyer syndrome is a disorder of sexual differentiation with an incidence of 1 in 80,000 population. Dysgenetic gonads have a propensity for malignant transformation particularly in the presence of Y chromosome and hence need prophylactic removal. We report a case of an adolescent girl who presented with primary amenorrhea who was identified as a case of 46 XY dysgenesis after karyotype studies. Extirpation of gonads were done laparoscopically and on histopathological assessment gonadoblastoma was detected. This case report aims to reiterate the importance of gonadectomy in patients with swyer syndrome as tumors could arise even in the absence of frank adnexal masses

Mandatory CSR expenditure and stock market liquidity

We investigate the nexus between corporate social responsibility (CSR) and firms' stock market liquidity. Using actual firm-level CSR expenditure data and a quasi-natural experiment setup of a mandated CSR regulation in India, we find that firms complying with the mandate experience significantly higher stock market liquidity, relative to non-CSR firms in the post-CSR mandate period. This effect seems to be more pronounced among CSR firms not affiliated to business groups, with concentrated promoter ownership, with low institutional ownership, with foreign sales and having operations in multiple locations. Further, we find that firms spending more on education and healthcare projects as part of their mandatory CSR engagement have higher stock market liquidity. Our results are in line with the conjecture that mandatory CSR regulation could lead to reduced information asymmetry and improved social and reputational capital, and thus improve the stock market liquidity of CSR firms. Finally, we show that mandated CSR firms, having superior stock market liquidity, obtain higher market valuations in the long run