Utrecht University

About: Utrecht University is a education organization based out in Utrecht, Utrecht, Netherlands. It is known for research contribution in the topics: Population & Poison control. The organization has 58176 authors who have published 139351 publications receiving 6214282 citations. The organization is also known as: UU & Universiteit Utrecht.

Comparative study of retinal vessel segmentation methods on a new publicly available database

Abstract: In this work we compare the performance of a number of vessel segmentation algorithms on a newly constructed retinal vessel image database. Retinal vessel segmentation is important for the detection of numerous eye diseases and plays an important role in automatic retinal disease screening systems. A large number of methods for retinal vessel segmentation have been published, yet an evaluation of these methods on a common database of screening images has not been performed. To compare the performance of retinal vessel segmentation methods we have constructed a large database of retinal images. The database contains forty images in which the vessel trees have been manually segmented. For twenty of those forty images a second independent manual segmentation is available. This allows for a comparison between the performance of automatic methods and the performance of a human observer. The database is available to the research community. Interested researchers are encouraged to upload their segmentation results to our website (http://www.isi.uu.nl/Research/Databases). The performance of five different algorithms has been compared. Four of these methods have been implemented as described in the literature. The fifth pixel classification based method was developed specifically for the segmentation of retinal vessels and is the only supervised method in this test. We define the segmentation accuracy with respect to our gold standard as the performance measure. Results show that the pixel classification method performs best, but the second observer still performs significantly better.

Handbook of bereavement research: Consequences, coping, and care

Abstract: New research continues to challenge our assumptions about the fundamental nature and course of grief: its roots in our biology, our emotions, and our social interactions. The "Handbook of Bereavement Research" provides a broad view of diverse contemporary approaches to bereavement, examining both normal adaptation and complicated manifestations of grief. In this volume, leading interdisciplinary scholars focus on three important themes in bereavement research: consequences, coping and care. In exploring the consequences of bereavement, authors examine developmental factors that influence grief both for the individual and the family at different phases of the life cycle. In exploring coping, they describe exciting new empirical studies about how people can and do cope with grief, without professional intervention. People do not grieve alone, so chapters on coping present new ways to understand grief at an interpersonal level as well. Until recently, intervention for the bereaved has not been scientifically guided and has become the subject of challenging differences of opinion and approach. Chapters in the care section of the volume critically examine interventions to date and provide guidance for assessment and more empirically guided treatment strategies. The "Handbook" provides an up-to-date comprehensive review of scientific knowledge about bereavement in an authoritative yet accessible way that should be useful reading for researchers, practitioners and health care professionals in the 21st century.

Multiple common variants for celiac disease influencing immune gene expression

Abstract: We performed a second-generation genome-wide association study of 4,533 individuals with celiac disease (cases) and 10,750 control subjects. We genotyped 113 selected SNPs with P(GWAS) < 10(-4) and 18 SNPs from 14 known loci in a further 4,918 cases and 5,684 controls. Variants from 13 new regions reached genome-wide significance (P(combined) < 5 x 10(-8)); most contain genes with immune functions (BACH2, CCR4, CD80, CIITA-SOCS1-CLEC16A, ICOSLG and ZMIZ1), with ETS1, RUNX3, THEMIS and TNFRSF14 having key roles in thymic T-cell selection. There was evidence to suggest associations for a further 13 regions. In an expression quantitative trait meta-analysis of 1,469 whole blood samples, 20 of 38 (52.6%) tested loci had celiac risk variants correlated (P < 0.0028, FDR 5%) with cis gene expression.

Polar PIN localization directs auxin flow in plants.

Abstract: Polar flow of the phytohormone auxin requires plasma membrane-associated PIN proteins and underlies multiple developmental processes in plants. Here we address the importance of the polarity of subcellular PIN localization for the directionality of auxin transport in Arabidopsis thaliana. Expression of different PINs in the root epidermis revealed the importance of PIN polar positions for directional auxin flow and root gravitropic growth. Interfering with sequence-embedded polarity signals directly demonstrates that PIN polarity is a primary factor in determining the direction of auxin flow in meristematic tissues. This finding provides a crucial piece in the puzzle of how auxin flow can be redirected via rapid changes in PIN polarity.