Unifying Sparsest Cut, Cluster Deletion, and Modularity Clustering Objectives with Correlation Clustering

Graph clustering, or community detection, is the task of identifying groups of closely related objects in a large network. In this paper we introduce a new community-detection framework called LambdaCC that is based on a specially weighted version of correlation clustering. A key component in our methodology is a clustering resolution parameter, $\lambda$, which implicitly controls the size and structure of clusters formed by our framework. We show that, by increasing this parameter, our objective effectively interpolates between two different strategies in graph clustering: finding a sparse cut and forming dense subgraphs. Our methodology unifies and generalizes a number of other important clustering quality functions including modularity, sparsest cut, and cluster deletion, and places them all within the context of an optimization problem that has been well studied from the perspective of approximation algorithms. Our approach is particularly relevant in the regime of finding dense clusters, as it leads to a 2-approximation for the cluster deletion problem. We use our approach to cluster several graphs, including large collaboration networks and social networks

Protests, plenums and politics: An analysis of the Bosnian Spring and its political (dis)continuity.

This paper discusses the protests in February 2014, Tuzla, Bosnia-Herzegovina. While these protests resulted in the resignation of local governments, the elections that followed suggest a continuation of ethno-nationalist politics. This research explains how the characteristics that defined the collective identity of the protest movement are undermined over time and how this, together with a lack of strategy, created a negative climate for mobilization at the time of the cantonal elections, October 2014. Hereby, this research shows that while Dayton is often seen as the major obstacle, other factors also influence attempts at democratization and political reform in Bosnia-Herzegovina

Long-term Clinical Outcome of Treatment for Chronic Hepatitis C

Worldwide, 170 million people are chronically infected with the hepatitis C virus. The infection leads to inflammation and fibrosis of the liver and may eventually lead to liver failure or development of hepatocellular carcinoma. It is known that treatment with pegylated interferon and ribavirin may lead to sustained suppression of the hepatitis C virus. The aim of this thesis is to investigate whether patients with a sustained virological response have a prolonged life expectancy and whether they have a decreased risk of developing liver failure and hepatocellular carcinoma. In a first study we compared the survival of chronic hepatitis C patients from different European centers with the general population. Patients with a sustained virological response had a life expectancy similar to the general population, matched for age and gender. We also investigated patients with advanced liver fibrosis. In this study, data were collected from more than 500 European and Canadian patients. Among sustained virological responders there was a spectaculair decrease in the risk of developing liver failure and the 5-year risk of dying from a liver-related cause had decreased from 12.9 to 4.4 percent, compared to non-responders. Finally, the course of the disease in treated patients with advanced fibrosis was compared to the natural history, as predicted by a mathematical model. This comparison also suggested an improved outcome for patients who had undergone treatment with peginterferon and ribavirin. For this work, B.J. Veldt received a stipend from the Netherlands organisation for health research and development

Exploring the relationship between teachers\u27 beliefs in mathematics and their instructional practice

This study explored the relationship between teachers\u27 beliefs about mathematics and their instructional practices. The personal epistemology of the case study elementary mathematics teachers was documented and analyzed to provide evidence of the connection between teachers\u27 beliefs and practice in an elementary school setting; This study was grounded in a theoretical framework of epistemological world views, particularly the comparison of belief across three epistemological world views: (1) the realist, (2) the contextualist, and (3) the relativist. Three areas of beliefs are addressed in this study: (1) beliefs about curriculum, (2) beliefs about pedagogy, and (3) beliefs about assessment. Through analysis of these beliefs specific to mathematics, this study identified which world view the case study teachers espouse and how this influenced each teacher\u27s mathematical classroom practice. This study sought to answer the following research questions: (1) What are teachers\u27 beliefs about curriculum, pedagogy, and assessment? (2) What practices provide evidence of teacher beliefs? (3) What is the relationship between teachers\u27 beliefs in mathematics and their instructional practices?;This design of the study was a qualitative case study. Participants in this study were three third grade teachers from different schools in the same school district located in the southwestern United States. These teachers provided the unit of analysis for the study. The schools were selected because they support a standards-based approach to mathematics mandated by state and district standards. The teachers selected for the study use similar third grade resources to implement standards-based mathematics curriculum in the elementary classroom. The participants\u27 perspectives are shared through interviews, observations, documents, and audio-visual materials. In this study, the teachers\u27 epistemological world view was examined and compared to their implementation of mathematics practices; From the domain analysis, many factors supported and hindered practice based on the world view of the teachers. The researcher categorized these domains based on broad external factors to narrow internal factors. The following domains were examined based on the data: (1) domain one: school district factors, (2) domain two: school culture factors, (3) domain three: physical classroom factors, and (4) domain four: individual teacher beliefs; Implications from this study included a need to: (1) provide teachers with an understanding of mathematic content and an understanding of beliefs about curriculum, pedagogy, and assessment, (2) provide courses for pre-service teachers and teachers that incorporates a comparison of world views into the mathematics coursework, (3) support collaborative efforts between teacher educators and school districts in designing a shared vision for world views, and (4) inform the mathematics domain in regards to world views to improve teaching