Thesaurus - an ideal tool for vocabulary control in post-coordinate systems : INIS Thesaurus - a case study

The complex conceptual relationships contained in multi-dimensional documents present the problem of inconsistency in subject analysis and vocabulary control for efficient retrieval is stressed. The development of Thesaurus, an important contribution for effective vocabulary control in mechanised IR systems which is among the many developmental efforts in this direction, is highlighted. The development, structure and design of INIS Thesaurus is given in detail. Adaptability of the INIS thesaurus to a computer-based information handling system is examine

Outcome analysis of upper and lower limb motor functions after anterior cervical discectomy and fusion for degenerative cervical disc disease

Background: Anterior cervical discectomy and fusion (ACDF) is the most commonly performed surgical procedure for symptomatic cervical disc disease. In this study, we analysed the upper and lower limb motor functions after ACDF for disc prolapse in patients with degenerative cervical disc disease. Methods: One hundred consecutive adult patients who underwent ACDF for single or two-level cervical disc prolapse during the study period (October 2015 to October 2017) were included in the study. Results: Preoperative motor deficits in limbs were noted in 73% (73/100) of the patients. Enhance recovery of motor deficits was noted in 72.6% (53/73) of these patients and persisting motor deficits in the remaining patients (20/73- 27.4%). Five patients (5/27- 18.5%) without any preoperative motor deficits developed motor deficits after ACDF. Detailed pre and postoperative (at the time of discharge) motor power (graded by MRC grade) in all 4 limbs (Shoulder abduction/adduction/flexion/extension, elbow flexion/extension, wrist flexion/extension, hip abduction/adduction/flexion/extension, knee flexion/extension, ankle flexion/extension) was recorded. Statistically significant improvement in motor power (as recorded at the time of discharge) was noted in all the tested muscle groups after ACDF. Conclusion: Early improvement in preoperative motor deficits can be expected in the majority of the patients with cervical PIVD following ACDF

Imaginary Potential as a Counter of Delay Time for Wave Reflection from a 1D Random Potential

We show that the delay time distribution for wave reflection from a one-dimensional random potential is related directly to that of the reflection coefficient, derived with an arbitrarily small but uniform imaginary part added to the random potential. Physically, the reflection coefficient, being exponential in the time dwelt in the presence of the imaginary part, provides a natural counter for it. The delay time distribution then follows straightforwardly from our earlier results for the reflection coefficient, and coincides with the distribution obtained recently by Texier and Comtet [C.Texier and A. Comtet, Phys.Rev.Lett. {\bf 82}, 4220 (1999)],with all moments infinite. Delay time distribution for a random amplifying medium is then derived . In this case, however, all moments work out to be finite.Comment: 4 pages, RevTeX, replaced with added proof, figure and references. To appear in Phys. Rev. B Jan01 200

Field Theoretical Quantum Effects on the Kerr Geometry

We study quantum aspects of the Einstein gravity with one time-like and one space-like Killing vector commuting with each other. The theory is formulated as a \coset nonlinear $\sigma$-model coupled to gravity. The quantum analysis of the nonlinear $\sigma$-model part, which includes all the dynamical degrees of freedom, can be carried out in a parallel way to ordinary nonlinear $\sigma$-models in spite of the existence of an unusual coupling. This means that we can investigate consistently the quantum properties of the Einstein gravity, though we are limited to the fluctuations depending only on two coordinates. We find the forms of the beta functions to all orders up to numerical coefficients. Finally we consider the quantum effects of the renormalization on the Kerr black hole as an example. It turns out that the asymptotically flat region remains intact and stable, while, in a certain approximation, it is shown that the inner geometry changes considerably however small the quantum effects may be.Comment: 16 pages, LaTeX. The hep-th number added on the cover, and minor typos correcte

Modulation Instability of Ultrashort Pulses in Quadratic Nonlinear Media beyond the Slowly Varying Envelope Approximation

We report a modulational instability (MI) analysis of a mathematical model appropriate for ultrashort pulses in cascaded quadratic-cubic nonlinear media beyond the so-called slowly varying envelope approximation. Theoretically predicted MI properties are found to be in good agreement with numerical simulation. The study shows the possibility of controlling the generation of MI and formation of solitons in a cascaded quadratic-cubic media in the few cycle regimes. We also find that stable propagation of soliton-like few-cycle pulses in the medium is subject to the fulfilment of the modulation instability criteria

Three-dimensional random Voronoi tessellations: From cubic crystal lattices to Poisson point processes

We perturb the SC, BCC, and FCC crystal structures with a spatial Gaussian noise whose adimensional strength is controlled by the parameter a, and analyze the topological and metrical properties of the resulting Voronoi Tessellations (VT). The topological properties of the VT of the SC and FCC crystals are unstable with respect to the introduction of noise, because the corresponding polyhedra are geometrically degenerate, whereas the tessellation of the BCC crystal is topologically stable even against noise of small but finite intensity. For weak noise, the mean area of the perturbed BCC and FCC crystals VT increases quadratically with a. In the case of perturbed SCC crystals, there is an optimal amount of noise that minimizes the mean area of the cells. Already for a moderate noise (a>0.5), the properties of the three perturbed VT are indistinguishable, and for intense noise (a>2), results converge to the Poisson-VT limit. Notably, 2-parameter gamma distributions are an excellent model for the empirical of of all considered properties. The VT of the perturbed BCC and FCC structures are local maxima for the isoperimetric quotient, which measures the degre of sphericity of the cells, among space filling VT. In the BCC case, this suggests a weaker form of the recentluy disproved Kelvin conjecture. Due to the fluctuations of the shape of the cells, anomalous scalings with exponents >3/2 is observed between the area and the volumes of the cells, and, except for the FCC case, also for a->0. In the Poisson-VT limit, the exponent is about 1.67. As the number of faces is positively correlated with the sphericity of the cells, the anomalous scaling is heavily reduced when we perform powerlaw fits separately on cells with a specific number of faces

Neutrino Masses, Baryon Asymmetry, Dark Matter and the Moduli Problem : A Complete Framework

Recent developments in string theory have led to "realistic" string compactifications which lead to moduli stabilization while generating a hierarchy between the Electroweak and Planck scales at the same time. However, this seems to suggest a rethink of our standard notions of cosmological evolution after the end of inflation and before the beginning of BBN. We argue that within classes of realistic string compactifications, there generically exists a light modulus with a mass comparable to that of the gravitino which generates a large late-time entropy when it decays. Therefore, all known mechanisms of generating the baryon asymmetry of the Universe in the literature have to take this fact into account. In this work, we find that it is still possible to naturally generate the observed baryon asymmetry of the Universe as well as light left-handed neutrino masses from a period of Affleck-Dine(AD) leptogenesis shortly after the end of inflation, in classes of realistic string constructions with a minimal extension of the MSSM below the unification scale (consisting only of right-handed neutrinos) and satisfying certain microscopic criteria described in the text. The consequences are as follows. The lightest left-handed neutrino is required to be virtually massless. The moduli (gravitino) problem can be naturally solved in this framework both within gravity and gauge mediation. The observed upper bound on the relic abundance constrains the moduli-matter and moduli-gravitino couplings since the DM is produced non-thermally within this framework. Finally, although not a definite prediction, the framework naturally allows a light right-handed neutrino and sneutrinos around the electroweak scale which could have important implications for DM as well as the LHC.Comment: 41 pages, no figures, journal version adde

External ventricular drainage for intraventricular hemorrhage

Background: Intervention to reduce intracranial pressure using External Ventricular Drain (EVD) is a common life saving measure in a neurosurgery intensive care unit(ICU). Objective: The present study was undertaken to assess the outcome of patients who underwent external ventricular drainage for intraventricular hemorrhage(IVH). Methods: The available data of the patients who underwent placement of external ventricular drain from February 2012 to May 2016 for intraventricular hemorrhage (IVH) at Narayana Medical College and Hospital, Nellore, was retrieved from the hospital case records and analyzed. Results: Total of 69 patients were included in this study. Mean age was 53.7 ±11.6 years. Clinical presentation included altered sensorium in 66 patients (96%), hemiparesis in 62 patients (90%) , vomiting in 40 patients (58%) and seizures in 9 patients (13%). Fifty two patients (75%) were known hypertensives and 10 patients (15%) were diabetic. Past history of smoking was recorded in 16(23%) patients and alcohol intake in 17 patients (25%). GCS at the time of admission was 3-8 (low) in 39 patients (57%), 9-12 in 23 patients(33%) and 13-15 in 7 patients (10%). At the time of admission, 60 patients ( 87%) had diastolic blood pressure more than 90 mmHg, 63 patients (91%) had systolic blood pressure more than 140 mmHg. Major site of hemorrhage was basal ganglia in 24 (35%), thalamus in 13 (19%), cerebellum in 5 (7%), brain stem in 3, frontal/temporal in 2 patients. SAH with IVH was noted in 12 patients (17%) and only IVH was noted in 10 patients (14%). Mean duration of external ventricular drainage was 4.6+1.7 days (Range 1-9 days). Mean hospital stay was 11.3±7.5 days and mean ICU stay was 8+5.4 days. Thirty eight patients (55%) died during hospital stay. At the time of discharge, poor out come (Glagow out come score 1-3) was noted in 52 patients (75%) and good out come (Glagow out come score-4,5) was noted in 17 patients. Among various parameters analyzed , poor GCS (3-8) at admission, history of smoking and alcohol intake were found to correlate significantly with poor outcome. None of the other factors like old age, site of bleed, pupillary asymmetry at admission, high blood pressure at admission, past history of hypertension and diabetes were found to correlate with poor outcome. Conclusions: Majority of the patients with intracranial hematomas with intraventricular extension presented in poor neurological condition (GCS= 3-8). Poor neurological condition at the time of admission, past history of smoking and alcohol intake were associated with poor outcome