4,633 research outputs found
The need for Helicobacter pylori eradiction therapy in patients with peptic ulcer bleeding
Peptic ulcer bleeding is an important complication of peptic ulceration. The condition carries significant morbidity and mortality despite advances in both endoscopic intervention techniques and pharmacological treatment. About one third of patients have a recurrence of bleeding within a few years of discharge. Before Helicobacter pylori was discovered, most of these patients were given maintenance therapy with antisecretory drugs or surgery to prevent a recurrence of the bleeding. Since the eradication of Helicobacter pylori reduces the recurrence of uncomplicated peptic ulcers, its eradication should also reduce peptic ulcer complications. The aim of this review is to discuss the value of eradicating Helicobacter pylori as part of the long-term management of bleeding peptic ulcers.published_or_final_versio
Short sales and price discovery in real estate markets
Indirect real estate (IRE) returns are often shown to lead direct real estate (DRE) returns. Apart from differences in liquidity, transaction costs, and management skills, the DRE market is also less complete than the IRE market – when negative shocks arrive, one can only short IRE (e.g. real estate stocks or REITs), but not DRE. This study investigates if short sales in the IRE market convey any information to the DRE market. Based on high-frequency (weekly) property price data in Hong Kong from 1999 to 2011, we found that short sales in the IRE market led DRE returns, even after controlling for the lagged IRE returns in a VAR model. This suggests that short sales contain private information on the real estate market that is not fully reflected in IRE returns. The spillover effect of short sales, however, weakened after the 2007 global financial crisis because increased uncertainty over the credibility of individual firms made short sales carry more firm-specific information than market-wide news.postprin
On output tracking using dynamic output feedback discrete-time sliding-mode controllers
This is the author's version of an artiucle subseqiently published in IEEE Transactions on Automatic Control. The definitive published version is available via doi: 10.1109/TAC.2007.904256In this note, an output feedback based discrete-time sliding-mode control scheme is proposed. It incorporates a steady-state tracking requirement through the use of integral action. Previous work has shown that with an appropriate choice of sliding surface, discrete-time sliding-mode control can be applied to nonminimum phase systems. The original scheme employed static output feedback and this imposed restrictions on the class of systems to which it was applicable - specifically a certain "fictitious" subsystem was required to be output feedback stabilizable. The scheme proposed in this note includes a compensator which broadens the class of systems for which the results are applicable. In the presence of bounded matched disturbances, ultimate boundedness results are obtained. It is also shown that in the presence of a class of sector bounded uncertainty, asymptotic stability can be achieved. © 2007 IEEE
Effective moving cast shadow detection for monocular color image sequences
For an accurate scene analysis in monocular image sequences, a robust segmentation of a moving object from the static background is generally required. However, the existence of moving cast shadow may lead to an inaccurate object segmentation, and as a result, lead to further erroneous scene analysis. An effective detection of moving cast shadow in monocular color image sequences is developed. Firstly, by realizing the various characteristics of shadow in luminance, chrominance, and gradient density, an indicator, called shadow confidence score, of the probability of the region classified as cast shadow is calculated. Secondly the canny edge detector is employed to detect edge pixels in the detected region. These pixels are then bounded by their convex hull, which estimates the position of the object. Lastly, by analyzing the shadow confidence score and the bounding hull, the cast shadow is identified as those regions outside the bounding hull and with high shadow confidence score. A number of typical outdoor scenes are evaluated and it is shown that our method can effectively detect the associated cast shadow from the object of interest.published_or_final_versio
Anomalous diffusivity and electric conductivity for low concentration electrolytes in nanopores
The dynamic properties of electrolytes in nanopores were studied using the equilibrium and non-equilibrium molecular dynamic simulations. The realistic primitive model and the restrictive primitive models that were widely used in liquid state theory were applied to the electrolyte model. The electrolytic ions that were found to be immersed in the water were treated as dielectric continuum or macroscopic dielectric continuum. Simulation studies for the discrete solvent primitive model were performed and detailed analysis of the characteristics of the ion radial density functions was done.published_or_final_versio
海浪發電
由於全球人口不斷增長,所以能源需求日益增加。地球上大部份的能源主要來自化石燃料。不過,燃燒化石燃料發電會釋出大量二氧化碳和污染物,造成溫室效應從而導致環境破壞;而且,化石燃料是有限的能源。雖然可用核原料發電,但是核能的安全問題與風險管理不斷受人們爭論。故此,對再生能源的研究及開發是刻不容緩的。本章主要討論其中一種再生能源,海浪發電的好處及近期一些研究成果。published_or_final_versio
A simplified but equally accurate C-13 urea breath test for Helicobacter pylori
published_or_final_versio
A randomised controlled study comparing the efficacy of once-daily triple therapy with twice-daily triple therapy in the eradication of Helicobacter pylori
published_or_final_versio
An evaluation of PyloriTek test for the diagnosis of Helicobacter pylori infection in Chinese - before and after eradication therapy
published_or_final_versio
- …