Topic tracking using chronological term ranking

Topic tracking (TT) is an important component of topic detection and tracking (TDT) applications. TT algorithms aim to determine all subsequent stories of a certain topic based on a small number of initial sample stories. We propose an alternative similarity measure based on chronological term ranking (CTR) concept to quantify the relatedness among news articles for topic tracking. The CTR approach is based on the fact that in general important issues are presented at the beginning of news articles. By following this observation we modify the traditional Okapi BM25 similarity measure using the CTR concept. Using a large standard test collection we show that our method provides a statistically significantly improvement with respect to the Okapi BM25 measure. The highly successful performance indicates that the approach can be used in real applications. © 2013 Springer-Verlag London

Germanene: the germanium analogue of graphene

Recently, several research groups have reported the growth of germanene, a new member of the graphene family. Germanene is in many aspects very similar to graphene, but in contrast to the planar graphene lattice, the germanene honeycomb lattice is buckled and composed of two vertically displaced sub-lattices. Density functional theory calculations have revealed that free-standing germanene is a 2D Dirac fermion system, i.e. the electrons behave as massless relativistic particles that are described by the Dirac equation, which is the relativistic variant of the Schrödinger equation. Germanene is a very appealing 2D material. The spin-orbit gap in germanene (~24 meV) is much larger than in graphene (<0.05 meV), which makes germanene the ideal candidate to exhibit the quantum spin Hall effect at experimentally accessible temperatures. Additionally, the germanene lattice offers the possibility to open a band gap via for instance an externally applied electrical field, adsorption of foreign atoms or coupling with a substrate. This opening of the band gap paves the way to the realization of germanene based field-effect devices. In this topical review we will (1) address the various methods to synthesize germanene (2) provide a brief overview of the key results that have been obtained by density functional theory calculations and (3) discuss the potential of germanene for future applications as well for fundamentally oriented studies

Coulomb drag in anisotropic systems: a theoretical study on a double-layer phosphorene

We theoretically study the Coulomb drag resistivity in a double-layer electron system with highly anisotropic parabolic band structure using Boltzmann transport theory. As an example, we consider a double-layer phosphorene on which we apply our formalism. This approach, in principle, can be tuned for other double-layered systems with paraboloidal band structures. Our calculations show the rotation of one layer with respect to another layer can be considered a way of controlling the drag resistivity in such systems. As a result of rotation, the off-diagonal elements of drag resistivity tensor have non-zero values at any temperature. In addition, we show that the anisotropic drag resistivity is very sensitive to the direction of momentum transfer between two layers due to highly anisotropic inter-layer electron-electron interaction and also the plasmon modes. In particular, the drag anisotropy ratio, \r{ho}yy/\r{ho}xx, can reach up to ~ 3 by changing the temperature. Furthermore,our calculations suggest that including the local field correction in dielectric function changes the results significantly. Finally, We examine the dependence of drag resistivity and its anisotropy ratio on various parameters like inter-layer separation, electron density, short-range interaction and insulating substrate/spacer.Comment: 10 pages, 9 figure

Abdominal pain in an adult with Type 2 diabetes: A case report

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Overexpression of ZEB2 in Peritumoral Liver Tissue Correlates with Favorable Survival after Curative Resection of Hepatocellular Carcinoma

BACKGROUND: ZEB2 has been suggested to mediate EMT and disease aggressiveness in several types of human cancers. However, the expression patterns of ZEB2 in hepatocellular carcinoma (HCC) and its effect on prognosis of HCC patients treated with hepatectomy are unclear. METHODOLOGY/PRINCIPAL FINDINGS: In this study, the methods of tissue microarray and immunohistochemistry (IHC) were utilized to investigate ZEB2 expression in HCC and peritumoral liver tissue (PLT). Receiver operating characteristic (ROC), spearman's rank correlation, Kaplan-Meier plots and Cox proportional hazards regression model were used to analyze the data. Up-regulated expression of cytoplasmic/nuclear ZEB2 protein was observed in the majority of PLTs, when compared to HCCs. Further analysis showed that overexpression of cytoplasmic ZEB2 in HCCs was inversely correlated with AFP level, tumor size and differentiation (P<0.05). Also, overexpression of cytoplasmic ZEB2 in PLTs correlated with lower AFP level (P<0.05). In univariate survival analysis, a significant association between overexpression of cytoplasmic ZEB2 by HCCs/PLTs and longer patients' survival was found (P<0.05). Importantly, cytoplasmic ZEB2 expression in PLTs was evaluated as an independent prognostic factor in multivariate analysis (P<0.05). Consequently, a new clinicopathologic prognostic model with cytoplasmic ZEB2 expression (including HCCs and PLTs) was constructed. The model could significantly stratify risk (low, intermediate and high) for overall survival (P = 0.002). CONCLUSIONS/SIGNIFICANCE: Our findings provide a basis for the concept that cytoplasmic ZEB2 expressed by PLTs can predict the postoperative survival of patients with HCC. The combined cytoplasmic ZEB2 prognostic model may become a useful tool for identifying patients with different clinical outcomes

ICT integration stages of teachers and factors affecting them

This study aims at investigating ICT integration stages of teachers and factors that might be having an effect on their stages. This study utilizes ACOT integration model as the theoretical basis for determining integration stages of teachers. As ICT penetrate every aspect of teaching and learning, determining teachers' quality of use ICT in their teaching practice becomes important. It is also imperative to understand the factors that play a role in their use of ICT. A quantitative approach was adopted for this study. A sample of 352 teachers was selected randomly out of 1009 teachers working in primary schools in Usak, Turkey. In order to gather data, a series of scales were employed. SPSS packet program was used to run statistical analysis, regression for the purpose of the study. Analysis of the data reveals that the teachers are in three different stages (as opposed to 5 different stages in ACOT's model) in ICT integration as it was found out with a similar study. When it comes to factors affecting teachers' integration stages, it appears different variables are having an effect in different stages. For Entry stage 1 behaviors, only extrinsic factors are important. When it comes to Adoption stage 2 behaviors, the most important variable is ease of use of the technology among 4 different variables. It is also clear that reaching up to Adoption stage 2 is necessary for the teachers for advancing to Advanced Adoption (the highest) stage of ICT integration. © Sila Science. All rights reserved

Effects of inhaled corticosteroids on growth in asthmatic children: A comparison of fluticasone propionate with budesonide

In asthmatic children inhaled corticosteroids are widely used. However, there are some concerns about the systemic adverse effects of these drugs, especially in the growing child. We performed this prospective study in order to compare the effects of 400 µg/day of budesonide (BUD) and 250 µg/day of fluticasone propionate (FP) on growth in prepubertal (aged 4-11.5 years), moderate persisting asthmatic children. One hundred patients (51 boys and 49 girls), who were randomized into two groups, were recruited for the study. The first group was treated with BUD, 2x 200 µg/day, and the second group was treated with FP, 2x 125 µg/day, by using a medium-size volume-spacer metered-dose inhaler. Growth in children with asthma who were treated by inhaled corticosteroids was calculated by growth velocity over a 12-month period. Comparisons between treatment groups were calculated by t-test and chi-square test. There were no significant differences between BUD and FP groups for sex, age, first height, and growth velocity. Moderate persisting, prepubertal asthmatic children treated with 250 µg/day of FP appeared to have no different linear growth than those children who received 400 µg/day of BUD. Copyright © 2005, OceanSide Publications, Inc

A model to explore Turkish teachers' ICT integration stages

The aim of the study is to determine teachers' ICT integration stages according to CEO Forum's standards and factors affecting their integration. Teachers are expected to use ICT in their teaching practice. Hence, it is crucial that their integration stages and factors affecting it are examined. A survey method was employed for this study. A sample of 200 teachers was selected randomly out of 460 teachers working in primary schools in Uşak, Turkey. Researchers of this study developed an ICT integration questionnaire. Analysis of the data reveals that the teachers are in three different stages in ICT integration. A significant relationship is discovered between feelings of inadequacy in using ICT and exhibiting stage 1 behaviors. It is also clear that the ICT knowledge of teachers is the most important variable for the teachers who were at the third (the highest) stage of ICT integration. A model showing interrelations among factors influencing ICT integration behaviors were drawn for further studies to be tested. © The Turkish Online Journal of Educational Technology

The instability of silicene on Ag(111)

We have used low energy electron microscopy to directly visualize the formation and stability of silicene layers on a Ag(111) substrate. Theoretical calculations call into question the stability of this graphene-like analog of silicon. We find that silicene layers are intrinsically unstable against the formation of an “sp3-like” hybridized, bulk-like silicon structure. The irreversible formation of this bulk-like structure is triggered by thermal Si adatoms that are created by the silicene layer itself. To add injury to insult, this same instability prevents the formation of a fully closed silicene layer or a thicker bilayer, rendering the future large-scale fabrication of silicene layers on Ag substrates unlikel