Kidney transplantation in children

Transplantation in children with kidney failure once presented many technical, immunologic, and logistic problems that led to worse patient and allograft survival, as compared with adults. Advances in all these areas and the development of pediatric-trial groups have resulted in dramatic improvements, such that young children now have the best long-term graft survival among all age groups, including adults

The Images of Incumbents in Great Britain and the United States

Incumbents in single member, simple plurality systems strive to develop name recognition and positive images of themselves. We propose to analyze the images that constituents in Great Britain and the United States have of their MPs and Congressmen and to measure the impact which incumbent activities have on those images. We also examine the normative expectations that constituents in both countries have of their representatives and how these expectations shape their evaluations. The data for this study comes from matching elite and voter surveys in Great Britain and the United States. Our results can be summarized as follows: 1) a large percentage of constituents in both countries believe that casework and protecting district interests are the most important functions of the representative; 2) those from working class, less well educated backgrounds are more inclined to prefer a service role for their representative than a policy role; 3) the evaluations that constituents have of their representatives reflects the importance of constituency service in their priorities as well; and 4) that representatives who undertake high levels of constituency service have better constituent images than other representatives

The Constituency Service Basis of the Personal Vote for U.S. Representatives and British Members of Parliament

Under the guise of the "incumbency advantage" American research of the past decade has devoted heavy emphasis to what may be termed the "personal vote" in Congressional elections. Is this phenomenon a purely American one, or is it something susceptible to comparative treatment? This paper contrasts the personal vote in the 1980 U. S. House elections with that in the 1979 British General Election. The analysis utilizes data from surveys conducted by the Center for Political Studies and British Gallup, respectively, in combination with interviews of House AAs and British MPs and party agents whose constituencies fall in the sampling frames of the mass surveys. The analysis finds an incumbency advantage or personal vote in Britain, much weaker than that in the U. S., but of somewhat greater importance than is commonly believed, As in the U. S. constituency service appears to be an important component of the personal vote

The House Is Not a Home: M.P.'s and Their Constituencies

The British parliamentary system supposedly denies MPs the electoral incentive and the staff resources to engage in constituency service in the style of members of the U.S. Congress. Backbench MPs presumably aspire to ministerial office and therefore concentrate their activity on the work of the House. Case studies of 17 MPs, however, reveal that the constituency orientations of MPs are more varied than the conventional wisdom suggests, that some resemble the Homestyle of U.S. representatives, and that nearly all believe that attention to their constituents can protect them against national electoral swings. A close examination of the constituency orientations of five MPs suggests the cross-national utility of Fenno's distinction between geographical, re-election, primary, and personal constituencies and his categories of "presentation of self.

Why Local Party Leaders Don't Support Nominating Centrists

Would giving party leaders more influence in primary elections in the United States decrease elite polarization? Some scholars have argued that political party leaders tend to support centrist candidates in the hopes of winning general elections. In contrast, the authors argue that many local party leaders - especially Republicans - may not believe that centrists perform better in elections and therefore may not support nominating them. They test this argument using data from an original survey of 1,118 county-level party leaders. In experiments, they find that local party leaders most prefer nominating candidates who are similar to typical co-partisans, not centrists. Moreover, given the choice between a more centrist and more extreme candidate, they strongly prefer extremists: Democrats do so by about 2 to 1 and Republicans by 10 to 1. Likewise, in open-ended questions, Democratic Party leaders are twice as likely to say they look for extreme candidates relative to centrists; Republican Party leaders are five times as likely. Potentially driving these partisan differences, Republican leaders are especially likely to believe that extremists can win general elections and overestimate the electorate's conservatism by double digits

Predictive models based on Support Vector Machines: whole-brain versus regional analysis of structural MRI in the Alzheimer’s disease

Decision-making systems trained on structural magnetic resonance imaging data of subjects affected by the Alzheimer's disease (AD) and healthy controls (CTRL) are becoming widespread prognostic tools for subjects with mild cognitive impairment (MCI). This study compares the performances of three classification methods based on support vector machines (SVMs), using as initial sets of brain voxels (ie, features): (1) the segmented grey matter (GM); (2) regions of interest (ROIs) by voxel-wise t-test filtering; (3) parceled ROIs, according to prior knowledge. The recursive feature elimination (RFE) is applied in all cases to investigate whether feature reduction improves the classification accuracy. We analyzed more than 600 AD Neuroimaging Initiative (ADNI) subjects, training the SVMs on the AD/CTRL dataset, and evaluating them on a trial MCI dataset. The classification performance, evaluated as the area under the receiver operating characteristic curve (AUC), reaches AUC = (88.9 ± .5)% in 20-fold cross-validation on the AD/CTRL dataset, when the GM is classified as a whole. The highest discrimination accuracy between MCI converters and nonconverters is achieved when the SVM-RFE is applied to the whole GM: with AUC reaching (70.7 ± .9)%, it outperforms both ROI-based approaches in predicting the AD conversion

Channeler Ant Model: 3D segmentation of medical images through ant colonies

In this paper the Channeler Ant Model (CAM) and some results of its applications to the analysis of medical images are described. The CAM is an algorithm able to segment 3D structures with different shapes, intensity and background. It makes use of virtual ant colonies and exploits their natural capabilities to modify the environment and communicate with each other by pheromone deposition. Its performance has been validated with the segmentation of 3D artificial objects and it has been already used successfully in lung nodules detection on Computer Tomography images. This work tries to evaluate the CAM as a candidate to solve the quantitative segmentation problem in Magnetic Resonance brain images: to evaluate the percentage of white matter, gray matter and cerebrospinal fluid in each voxel