Showing 19909–19922 of 21,218 results for "Satyam Sahu"

Journals 2019 EN

In vitro Assessment of Fosfomycin: A Beacon of Hope in Drug Resistant Organisms Causing Urinary Tract Infections

Mridu Anand · Chinmoy Sahu · Arti Negi +1 more

Urinary tract infections (UTI) are the most common bacterial infections affecting humans.. Fosfomycin has been approved for use in uncomplicated UTI caused by E. coli and Enterococcus. However, data regarding sensitivity of organisms causing hospital acquired or complicated UTI is scarce worldwide. We aimed to determine the in vitro sensitivity of drug resistant organisms causing hospital acquired and complicated UTI towards fosfomycin. Materials and Methods: Over a 6 month period, urine samples were processed as per standard microbiological protocols. Bacterial isolates were identified by routine microbiological methods followed by automated methods. Antibiotic sensitivity tests were done for different antibiotics. Fosfomycin sensitivity was tested by disc diffusion assay and minimum inhibitory concentration (MIC) was determined by E test method. Results: A total of 248` organisms causing hospital acquired and/or complicated UTI were isolated Original Research Article Anand et al.; JAMMR, 30(2): 1-9, 2019; Article no.JAMMR.50150 2 of which E. coli 88(35.48%) was most common followed by K. pneumoniae 78(31.45%) and P. aeruginosa 64(25.80%). Of 248, 92.74% (230/248) isolates were sensitive to fosfomycin. All the E. coli isolates were sensitive to fosfomycin with a low MIC (range 0.06416 mg/L) while 97.43% (76/78) of the K. pneumoniae and 71.87% (46/64) P. aeruginosa of isolates were sensitive with a higher MIC (range 0.532 mg/L and 664mg/L respectively). Fosfomycin MIC geometric mean among E. coli, K. pneumoniae and P. aeruginosa was; 1.05, 7.19 and 19.61 mg/L respectively. K. pneumoniae and P. aeruginosa showed a significantly higher geometric mean MIC compare to E. coli (P <0.0001). Conclusions: This study suggests that fosfomycin has the potential to replace the parenteral antibiotics for treating complicated or hospital acquired lower UTI especially in case of Enterobacteriaceae.

Sciencedomain International
Resource 2019 EN

Field Generated by Division Points of Certain Formal Group Laws

Soumyadip Sahu

In this article we study the Galois group of field generated by divisionpoints of special class of formal group laws and prove an equivalent conditionfor the group to be abelian. Further, we explore relations between theendomorphism ring of a formal group and the Galois group of field generated bydivision points.

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Resource 2019 EN

Field Generated by Division Points of Certain Formal Group Laws - II

Soumyadip Sahu

The article investigates several questions about field generated by certainformal group laws. This is continuation of a study initiated by the author inprior article titled 'Field Generated by Division Points of Certain FormalGroup Laws'.

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Resource 2019 EN

Towards Gradient Free and Projection Free Stochastic Optimization

Anit Kumar Sahu · Manzil Zaheer · Soummya Kar

This paper focuses on the problem of \emph{constrained} \emph{stochastic}optimization. A zeroth order Frank-Wolfe algorithm is proposed, which inaddition to the projection-free nature of the vanilla Frank-Wolfe algorithmmakes it gradient free. Under convexity and smoothness assumption, we show thatthe proposed algorithm converges to the optimal objective function at a rate$O\left(1/T^{1/3}\right)$, where $T$ denotes the iteration count. Inparticular, the primal sub-optimality gap is shown to have a dimensiondependence of $O\left(d^{1/3}\right)$, which is the best known dimensiondependence among all zeroth order optimization algorithms with one directionalderivative per iteration. For non-convex functions, we obtain the\emph{Frank-Wolfe} gap to be $O\left(d^{1/3}T^{-1/4}\right)$. Experiments onblack-box optimization setups demonstrate the efficacy of the proposedalgorithm.

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Resource 2019 EN

Right-handed Neutrino Dark Matter with Radiative Neutrino Mass in Gauged $B-L$ Model

Debasish Borah · Dibyendu Nanda · Nimmala Narendra +1 more

We study the possibility of right-handed neutrino dark matter (DM) in gauged$U(1)_{B-L} \times Z_2$ extension of the standard model augmented by anadditional scalar doublet, being odd under the $Z_2$ symmetry, to give rise thescotogenic scenario of radiative neutrino masses. Due to lepton portalinteractions, the right-handed neutrino DM can have additional co-annihilationchannels apart from the usual annihilations through $Z_{B-L}$ which give riseto much more allowed mass of DM from relic abundance criteria, even away fromthe resonance region like $M_{\rm DM} \approx M_{Z_{B-L}}/2$. This enlargedparameter space is found to be consistent with neutrino mass constraints whilebeing sensitive to direct detection experiments of DM as well as rare decayexperiments looking for charged lepton flavour violating decays like $\mu\rightarrow e \gamma$. Due to the possibility of the $Z_2$ odd scalar doubletbeing the next to lightest stable particle that can be sufficiently produced incolliders by virtue of its gauge interactions, one can have interestingsignatures like displaced vertex or disappearing charged tracks provided thatthe mass splitting $\delta M$ between DM and the next to lightest stableparticle (NLSP) is small. In particular, if $\delta M < m_\tau=1.77$ GeV, thenwe get large displaced vertex signature of NLSP while being consistent withneutrino mass, lepton flavour violation and observed relic density.

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Resource 2019 EN

Field Generated by Division Points of Certain Formal Group Laws -- III

Soumyadip Sahu

Several questions about the Galois group of field generated by certain onedimensional formal group laws are studied. This is continuation of author'sprior article titled 'Field Generated by Division Points of Certain FormalGroup Laws - II'. General formalism related to $\pi$-divisible groups isdiscussed in appendix.

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Resource 2019 EN

A Mini-review on Vector-like Leptonic Dark Matter, Neutrino Mass and Collider Signatures

Subhaditya Bhattacharya · Purusottam Ghosh · Nirakar Sahoo +1 more

We review a class of models in which the Standard Model (SM) is augmented byvector-like leptons: one doublet and a singlet, which are odd under an unbrokendiscrete $Z_2$ symmetry. As a result, the neutral component of these additionalvector-like leptons are stable and behave as dark matter. We study thephenomenological constraints on the model parameters and elucidate theparameter space for relic density, direct detection and collider signatures ofdark matter. In such models, we further add a scalar triplet of hypercharge twoand study the consequences. In particular, after electro weak symmetry breaking(EWSB), the triplet scalar gets an induced vacuum expectation value (vev),which yield Majorana masses not only to the light neutrinos but also tovector-like leptonic doublet DM. Due to the Majorana mass of DM, the $Z$mediated elastic scattering with nucleon is forbidden and hence allowing themodel to survive from stringent direct search bound. The DM without scalartriplet lives in a small singlet-doublet leptonic mixing region ($\sin\theta\le 0.1$) due to large contribution from singlet component and have small massdifference ($\Delta m \sim 10$ GeV) with charged companion, the NLSP (next tolightest stable particle), to aid co-annihilation for yielding correct relicdensity. Both these observations change to certain extent in presence of scalartriplet to aid observability of hadronically quiet leptonic final states atLHC, while one may also confirm/rule-out the model through displaced vertexsignal of NLSP, a characteristic signature of the model in relic density anddirect search allowed parameter space.

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Resource 2019 EN

Handcrafted vs Deep Learning Classification for Scalable Video QoE Modeling

Dasari Mallesham · Christina Vlachou · Shruti Sanadhya +4 more

Mobile video traffic is dominant in cellular and enterprise wirelessnetworks. With the advent of diverse applications, network administrators facethe challenge to provide high QoE in the face of diverse wireless conditionsand application contents. Yet, state-of-the-art networks lack analytics forQoE, as this requires support from the application or user feedback. Whilethere are existing techniques to map QoS to QoE by training machine learningmodels without requiring user feedback, these techniques are limited to onlyfew applications, due to insufficient QoE ground-truth annotation for ML. Toaddress these limitations, we focus on video telephony applications and modelkey artefacts of spatial and temporal video QoE. Our key contribution isdesigning content- and device-independent metrics and training across diverseWiFi conditions. We show that our metrics achieve a median 90% accuracy bycomparing with mean-opinion-score from more than 200 users and 800 videosamples over three popular video telephony applications -- Skype, FaceTime andGoogle Hangouts. We further extend our metrics by using deep neural networks,more specifically we use a combined CNN and LSTM model. We achieve a medianaccuracy of 95% by combining our QoE metrics with the deep learning model,which is a 38% improvement over the state-of-the-art well known techniques.

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Resource 2019 EN

Divergence Framework for EEG based Multiclass Motor Imagery Brain Computer Interface

Satyam Kumar · Tharun Kumar Reddy · Laxmidhar Behera

Similar to most of the real world data, the ubiquitous presence ofnon-stationarities in the EEG signals significantly perturb the featuredistribution thus deteriorating the performance of Brain Computer Interface. Inthis letter, a novel method is proposed based on Joint ApproximateDiagonalization (JAD) to optimize stationarity for multiclass motor imageryBrain Computer Interface (BCI) in an information theoretic framework.Specifically, in the proposed method, we estimate the subspace which optimizesthe discriminability between the classes and simultaneously preservestationarity within the motor imagery classes. We determine the subspace forthe proposed approach through optimization using gradient descent on anorthogonal manifold. The performance of the proposed stationarity enforcingalgorithm is compared to that of baseline One-Versus-Rest (OVR)-CSP and JAD onpublicly available BCI competition IV dataset IIa. Results show that animprovement in average classification accuracies across the subjects over thebaseline algorithms and thus essence of alleviating within sessionnon-stationarities.

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Resource 2019 EN

Perturbation of Quantum Harmonic oscillator and its effect on the Quantum Field Theory

Sankarshan Sahu

Here a special case of perturbation in quantum harmonic oscillator isstudied. Here we assume the perturbed potential to be a Harmonic Oscillatorthat has been shifted in the position space.We construct the new creation andannihilation operators for the new Hamiltonian to find out its energyeigenstates. What is interesting about the solution of this system is that wefind out that the ground state of this system is a coherent state of the groundstate of the original harmonic oscillator. We know that the Hamiltonian ofelectromagnetic field is similar to that of the harmonic oscillator where theelectric field and magnetic field are expressed in terms of time evolution ofannihilation and creation operators. According to the quantum electromagneticfield theory, photon states are expressed as the coherent states of the groundstates of the unperturbed harmonic oscillator.In the previous research works,ithas been established how coherent states provide a better picture of Electricfield compared to the energy eigenstates. This paper mainly deals with why thecoherent states provide a more complete picture of electric and magnetic fieldtheory compared to just energy eigenstates. Here we find how our perturbationact as a coherent state generator and adds a new term in the Hamiltonian. ThePerturbation is thought to arise from the only available interaction i.e.observation. The perturbation also explains how observation leads to coherenceof photon states. We will find out how the new perturbation affects the timeevolution of electromagnetic field. This also explains how the classicalelectromagnetic field theory takes into account the factor of observation, dueto which the classical laws are in perfect agreement with the quantum laws.

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