University of Ioannina

About: University of Ioannina is a education organization based out in Ioannina, Greece. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 7654 authors who have published 20594 publications receiving 671560 citations. The organization is also known as: Panepistimio Ioanninon.

Multiple-Treatments Meta-analysis of Chemotherapy and Targeted Therapies in Advanced Breast Cancer

Abstract: Background Many systemic nonhormonal regimens have been evaluated across several hundreds of randomized trials in advanced breast cancer. We aimed to quantify the relative merits of these regimens in prolonging survival. Methods We performed a systematic review of all trials that compared different regimens involving chemotherapy and/or targeted therapy in advanced breast cancer (1973 – 2007). Regimens were categorized a priori into different treatment types. We performed multiple-treatments meta-analysis and calculated hazard ratios for each treatment category relative to monotherapy with old agents (ie, regimens not including anthracyclines, anthracenediones, vinorelbine, gemcitabine, capecitabine, taxanes, marimastat, thalidomide, trastuzumab, lapatinib, or bevacizumab). Results We identified 370 eligible randomized trials (54 189 patients), of which 172 (31 552 patients) compared different types of treatment. Survival data from 148 comparisons pertaining to 128 of the 172 trials (26 031 patients, 22 different types of treatment) were available for inclusion in the multiple-treatments metaanalysis. Compared with single-agent chemotherapy with old nonanthracycline drugs, anthracycline regimens achieved 22% – 33% relative risk reductions in mortality (ie, hazard ratio [HR] for standard-dose anthracycline-based combination: 0.67, 95% credibility interval [CrI] 0.57 – 0.78). Several newer regimens achieved further benefits (eg, HR [95% CrI] 0.67 [0.55 – 0.81] for single-drug taxane, 0.64 [0.53 – 0.78] for combination of anthracyclines with taxane, 0.49 [0.37 – 0.67] for taxane-based combination with capecitabine or gemcitabine), and similar benefits were seen with several regimens including molecular targeted treatments. Most regimens had very similar efficacy profiles (<5% difference in HR) as first- and subsequentline therapies. Conclusions Stepwise improvements in efficacy of chemotherapy and targeted treatments cumulatively have achieved major improvements in the survival of patients with advanced breast cancer. Many options that can be used in first and subsequent lines of therapy have comparable efficacy profiles. J Natl Cancer Inst 2008;100: 1780 – 1791

Sharp conditions for the oscillation of delay difference equations

Abstract: Suppose that { p n } is a nonnegative sequence of real numbers and let k be a positive integer. We prove that \frac{{k^k }} {{\left( {k + 1} \right)^{k + 1} }} \]" id="E3" xmlns:mml="http://www.w3.org/1998/Math/MathML"> lim n → ∞ inf [ 1 k ∑ i = n − k n − 1 p i ] > k k ( k + 1 ) k + 1 is a sufficient condition for the oscillation of all solutions of the delay difference equation A n + 1 − A n + p n A n − k = 0 , n = 0 , 1 , 2 , … . This result is sharp in that the lower bound k k / ( k + 1 ) k + 1 in the condition cannot be improved. Some results on difference inequalities and the existence of positive solutions are also presented.

Supervisory effectiveness and bank risk

Abstract: This paper investigates the role of banking supervision in controlling bank risk. Banking supervision is measured in terms of enforcement outputs (i.e., on-site audits and sanctions). Our results show an inverted U-shaped relationship between on-site audits and bank risk, while the relationship between sanctions and risk appears to be linear and negative. We also consider the combined effect of effective supervision and banking regulation (in the form of capital and market discipline requirements) on bank risk. We find that effective supervision and market discipline requirements are important and complementary mechanisms in reducing bank fragility. This is in contrast to capital requirements, which prove to be rather futile in controlling bank risk, even when supplemented with a higher volume of on-site audits and sanctions.

The Global Kernel $k$ -Means Algorithm for Clustering in Feature Space

Abstract: Kernel k-means is an extension of the standard k-means clustering algorithm that identifies nonlinearly separable clusters. In order to overcome the cluster initialization problem associated with this method, we propose the global kernel k-means algorithm, a deterministic and incremental approach to kernel-based clustering. Our method adds one cluster at each stage, through a global search procedure consisting of several executions of kernel k-means from suitable initializations. This algorithm does not depend on cluster initialization, identifies nonlinearly separable clusters, and, due to its incremental nature and search procedure, locates near-optimal solutions avoiding poor local minima. Furthermore, two modifications are developed to reduce the computational cost that do not significantly affect the solution quality. The proposed methods are extended to handle weighted data points, which enables their application to graph partitioning. We experiment with several data sets and the proposed approach compares favorably to kernel k-means with random restarts.