Oral Malodour – A Review

Oral malodour (OM) has been recognized in the literature since ancient times, but only in the last 15 years it has come to the forefront of public and dental professional awareness.At least 50% of the population suffers from a chronic OM condition, causing personal discomfort and social embarrassment that often lead to emotional distress. Moreover, the consequences of OM may be more than social in that it may be a symptom of serious local/systemic conditions. Recent research has shown that sulphur-producing bacteria could be the primary source of this condition.KEYWORDS: Oral malodour, Volatile sulphur compounds ,Halitosi

Island Size Selectivity during 2D Ag Island Coarsening on Ag (111)

We report on early stages of submonolayer Ag island coarsening on Ag(111) surface at room temperature ($300$ K) carried out using realistic kinetic Monte Carlo (KMC) simulations. We find that during early stages, coarsening proceeds as a sequence of selected island sizes creating peaks and valleys in the island size distribution. We find that island-size selectivity is due to formation of kinetically stable islands for certain sizes because of adatom detachment/attachment processes and large activation barrier for kink detachment. In addition, we find that the ratio of number of adatom attachment to detachment processes to be independent of parameters of initial configuration and also on the initial shapes of the islands confirming that island-size selectivity is independent of initial conditions.These simulations were carried out using a very large database of processes identified by their local environment and whose activation barriers were calculated using the embedded-atom method

The Chemical Compositions of the SRd Variable Stars-- II. WY Andromedae, VW Eridani, and UW Librae

Chemical compositions are derived from high-resolution spectra for three stars classed as SRd variables in the General Catalogue of Variable Stars. These stars are shown to be metal-poor supergiants: WY And with [Fe/H] = -1.0, VW Eri with [Fe/H] = -1.8, and UW Lib with [Fe/H] = -1.2. Their compositions are identical to within the measurement errors with the compositions of subdwarfs, subgiants, and less evolved giants of the same FeH. The stars are at the tip of the first giant branch or in the early stages of evolution along the asymptotic giant branch (AGB). There is no convincing evidence that these SRd variables are experiencing thermal pulsing and the third dredge-up on the AGB. The SRds appear to be the cool limit of the sequence of RV Tauri variables.Comment: 14 pages, 1 figure, 4 table

Classification of Acute Leukemia using Fuzzy Neural Networks

Accurate classification of cancers based on microarray gene expressions is very important for doctors to choose a proper treatment. In this paper, we compared ten filter based gene selection methods in order to differentiate acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) in leukemia dataset. Dimensionality reduction methods, such as Spearman Correlation Coefficient and Wilcoxon Rank Sum Statistics are used for gene selection. The experimental results showed that the proposed gene selection methods are efficient, effective, and robust in identifying differentially expressed genes. Adopting the existing SVM-based and KNN-based classifiers, the selected genes by filter based methods in general give more accurate classification results, typically when the sample class sizes in the training dataset are unbalanced

Chemical composition of A--F type post-AGB candidates

An abundance analysis has been conducted for a sample of nine post-AGB candidate stars; eight of them have not been explored before. We find four very promising objects like HD 105262, HD 53300 and CpD$-62^o5428$ among them. We find strong evidence of dust-gas separation through selective depletion of refractive elements in HD 105262. The same effect is also observed in HD 53300, CpD$-62^o5428$ and HD 114855 although abundance peculiarities are relatively smaller for the last two stars. We find strong enrichment of nitrogen for HD 725, HD 842, HD 1457, HD 9233 and HD 61227 but no further evidence to support their post-AGB nature. We have compared the observed [N/C] ratios of these stars with the predictions of evolutionary models which include the rotation induced mixing.Comment: Accepted in MNRAS, 18 pages, 12 figure

Does the Blazar Gamma-Ray Spectrum Harden with Increasing Flux? Analysis of 9 Years of EGRET Data

The Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory (CGRO) discovered gamma-ray emission from more than 67 blazars during its 9 yr lifetime. We conducted an exhaustive search of the EGRET archives and selected all the blazars that were observed multiple times and were bright enough to enable a spectral analysis using standard power-law models. The sample consists of 18 flat-spectrum radio quasars(FSRQs), 6 low-frequency peaked BL Lac objects (LBLs) and 2 high-frequency peaked BL Lac objects (HBLs). We do not detect any clear pattern in the variation of spectral index with flux. Some of the blazars do not show any statistical evidence for spectral variability. The spectrum hardens with increasing flux in a few cases. There is also evidence for a flux-hardness anticorrelation at low fluxes in five blazars. The well-observed blazars (3C 279, 3C 273, PKS 0528+134, PKS 1622-297 PKS 0208-512) do not show any overall trend in the long-term spectral dependence on flux, but the sample shows a mixture of hard and soft states. We observed a previously unreported spectral hysteresis at weekly timescales in all three FSRQs for which data from flares lasting for ~(3-4) weeks were available. All three sources show a counterclockwise rotation, despite the widely different flux profiles. We analyze the observed spectral behavior in the context of various inverse Compton mechanisms believed to be responsible for emission in the EGRET energy range. Our analysis uses the EGRET skymaps that were regenerated to include the changes in performance during the mission