1,441 research outputs found
Development policy under fire? The politicization of European external relations
In the past few years decision‐making processes and the normative underpinnings of EU external relations have become subject to intense debate in the European institutions, member states and the wider public. Previous research suggests that there is variation in the extent to which individual domains of EU external relations are politicized and contested. This special issue aims to theorize further and investigate empirically this, using the example of European development policy and its relations with other external policies. We introduce two new mechanisms that drive politicization dynamics. We argue that politicization can be diffused horizontally from one policy field to another, which we call horizontal politicization. We also investigate how the politicization of EU external policies in third countries occurs and influences politicization dynamics in the EU, which we call outside‐in politicization. The introduction to the special issue presents our theoretical approach and summarizes the key findings from the special issue
Similarities and Differences in Genome-Wide Expression Data of Six Organisms
Comparing genomic properties of different organisms is of fundamental importance in the study of biological and evolutionary principles. Although differences among organisms are often attributed to differential gene expression, genome-wide comparative analysis thus far has been based primarily on genomic sequence information. We present a comparative study of large datasets of expression profiles from six evolutionarily distant organisms: S. cerevisiae, C. elegans, E. coli, A. thaliana, D. melanogaster, and H. sapiens. We use genomic sequence information to connect these data and compare global and modular properties of the transcription programs. Linking genes whose expression profiles are similar, we find that for all organisms the connectivity distribution follows a power-law, highly connected genes tend to be essential and conserved, and the expression program is highly modular. We reveal the modular structure by decomposing each set of expression data into coexpressed modules. Functionally related sets of genes are frequently coexpressed in multiple organisms. Yet their relative importance to the transcription program and their regulatory relationships vary among organisms. Our results demonstrate the potential of combining sequence and expression data for improving functional gene annotation and expanding our understanding of how gene expression and diversity evolved
Equine cervical intervertebral disc degeneration is associated with location and MRI features
Morphology of the equine cervical intervertebral disc is different from that in humans and small companion animals and published imaging data are scarcely available. The objectives of this exploratory, methods comparison study were (a) to describe MRI features of macroscopically nondegenerated and degenerated intervertebral discs (b) to test associations between spinal location and macroscopic degeneration or MRI-detected annular protrusion and between MRI-detected annular protrusion and macroscopic degeneration, and (c) to define MRI sequences for characterizing equine cervical intervertebral disc degeneration. Ex vivo MRI of intervertebral discs was performed in 11 horses with clinical signs related to the cervical region prior to macroscopic assessment. Mixed-effect logistic regression modeling included spinal location, MRI-detected annular protrusion, and presence of macroscopic degeneration with "horse" as random effect. Odds ratio and 95% confidence interval were determined. Reduced signal intensity in proton density turbo SE represented intervertebral disc degeneration. Signal voids due to presence of gas and/or hemorrhage were seen in gradient echo sequences. Presence of macroscopic intervertebral disc degeneration was significantly associated with spinal location with odds being higher in the caudal (C5 to T1) versus cranial (C2 to C5) part of the cervical vertebral column. Intervertebral discs with MRI-detected annular protrusion grades 2-4 did have higher odds than with grade 1 to have macroscopic degeneration. It was concluded that MRI findings corresponded well with gross macroscopic data. Magnetic resonance imaging of the equine cervical intervertebral disc seems to be a promising technique, but its potential clinical value for live horses needs to be explored further in a larger and more diverse population of horses
Cervical articular process joint osteochondrosis in Warmblood foals
Background: In Warmblood horses, degenerative joint disease is involved in cervical malformation and malarticulation (CVM). The degree of contribution of articular process joint (APJ) osteochondrosis (OC) is not clear.
Objectives: (a) To explore the presence of predilection sites for APJ OC in cervical and cranial thoracic vertebral columns of Warmblood foals and (b) to examine the correlation of such a site with the predilection site of CVM.
Study design: Case series.
Methods: Seven hundred APJ facets of C2 to T2 of 29 foals (11 months gestation to 12 months [median age 7 days; range 365 days; 95% confidence interval [95% CI] 2-47 days]) were examined for OC and prevalence between joints, and the predilection site for CVM and the cranial cervical vertebral column were evaluated.
Results: About 20.6% of facets revealed OC. There was no predilection site. Prevalence decreased with age up to 1 year (odds ratio [OR] 0.997; (95% CI 0.975-0.998)) but not up to 5 months. Severity increased with age in all age ranges (up to 1 year OR 1.023; 95% CI 1.005-1.049; >1-5 months, OR 1.203; 95% CI 1.014e+00-1.921; up to 1 month, OR 1.114; 95% CI 1.041-1.228). Highest prevalence was in cranial facets of the cervical and cervical-thoracic joints and in caudal facets of the thoracic joint up to 1 year and up to 1 month (OR 0.364; 95% CI 0.170-0.745, OR 0.434; 95% CI: 0.235-0.782, OR 7.665; 95% CI: 1.615-66.553 and OR 0.400; 95% CI 0.170-0.880, OR 0.351; 95% CI 0.172-0.700, OR 5.317; 95% CI 1.098-44.344 respectively).
Main limitations: Two-thirds of the foals were less than 1 month of age.
Conclusions: Articular process joint OC in Warmblood foals is common and is not more prevalent at CVM predilection sites, suggesting that abnormalities of enchondral ossification may not be major contributors to CVM
Hacking the centromere chromatin code: dissecting the epigenetic regulation of centromere identity
The centromere is a specialized chromatin domain that serves as the
assembly site for the mitotic kinetochore structure, thereby playing a
fundamental role in facilitating the maintenance of the genetic information. A
histone H3 variant termed CENP-A is specifically found at all active
centromeres. Beyond this, however, little is known about how and to which
extent the chromatin environment of centromeres modulates and contributes
towards centromere identity and function.
Here, I have employed a novel Human Artificial Chromosome (HAC),
the centromere of which can be targeted by fusions to the tet repressor, to
characterize the chromatin environment underlying active kinetochores, as
well as to specifically probe the role of this environment in the maintenance
of kinetochore structure and function. My data demonstrate that centromeric
chromatin resembles the downstream regions of actively transcribed genes.
This includes the previously unrecognized presence of histone H3
nucleosomes methylated at lysine 36 within the chromatin underlying
functional kinetochores. Targeted manipulation of this chromatin through
tethering of a heterochromatin-seeding transcriptional repressor results in the
inactivation of HAC kinetochore function concomitant with a hierarchical
disassembly of the structure. Through an even more selective engineering of
the HAC centromere chromatin, I have provided evidence supporting a
critical role for nucleosomes dimethylated at lysine 4 on histone H3 in
facilitating local transcription of the underlying DNA.
Tethering of different chromatin-modifying activities into the HAC
kinetochore collectively reveals a critical role for both, histone H3
dimethylated on lysine 4 and low-level, non-coding transcription in the
maintenance of the CENP-A chromatin domain. On one hand, repression of
centromeric transcription negatively correlates with the maintenance of CENP-A and ultimately results in the loss of kinetochore function. On the
other hand, increasing kinetochore-associated RNA polymerase activity to
within physiological levels for euchromatin is associated with rapid loss of
CENP-A from the HAC centromere. Together, my data point towards the
requirement for a delicate balance of transcriptional activity that is required to
shape and maintain the chromatin environment of active centromeres
Influence of intraoral scanning on the quality of preparations for all-ceramic single crowns
OBJECTIVES To evaluate the influence of intraoral scanning on the quality of preparations for all-ceramic single crowns.
MATERIAL AND METHODS A total of 690 randomly selected and anonymized in vivo single crown preparations were examined. Three hundred twenty-three preparations were directly recorded with an intraoral scanner (group IS). Data from plaster casts digitized by a laboratory scanner (group ID; N = 367) served as control. Comparisons included convergence angle, marginal design, marginal substance reduction, homogeneity of the finish line, and undercuts. Evaluation was performed using fully automated specialized software. Data were analyzed applying Kolmogorov-Smirnov, Mann-Whitney U test, and Fisher's exact test. Level of significance was set at p < 0.05. RESULTS Convergence angle was above optimum in both groups, but significantly larger for group IS (p < 0.001). Marginal design was more ideal in group IS concerning the absence of featheredge design (p < 0.001) and reverse bevel (p = 0.211). Marginal substance reduction was closer to prerequisites for all-ceramic restorations in group IS (p < 0.001). Finish lines were more homogeneous in group IS regarding the uniformity of their course (p < 0.001). Undercuts were more frequently found in group ID than in group IS (p < 0.001).
CONCLUSIONS Intraoral scanning of prepared teeth has positive impact on the quality of preparations for all-ceramic single crowns regarding marginal substance reduction, marginal design, homogeneity of the finish line, and undercuts.
CLINICAL RELEVANCE Accurate preparation design represents a fundamental condition for success of ceramic crowns. Since there is potential for optimization, intraoral scanning might enhance preparation quality providing instant visual feedback
Electronics and Sensor Subsystem Design for Daedalus 2 on REXUS 29: An Autorotation Probe for Sub-Orbital Re-Entry
The Daedalus 2 mission aboard REXUS 29 is a technology demonstrator for an
alternative descent mechanism for very high altitude drops based on
auto-rotation. It consists of two probes that are ejected from a sounding
rocket at an altitude of about 80 km and decelerate to a soft landing using
only a passive rotor with pitch control. This type of autonomous, scientific
experiment poses great challenges upon the electronics subsystem, which include
mechanical stress, power system reliability, sensor redundancy, subsystem
communication, and development procedures. Based on the data gathered in
Daedalus 1 multiple new approaches were developed to fulfill these
requirements, such as redundant communication links, mechanical decoupling of
PCBs and fault-tolerant power source selection.Comment: 8 pages, 10 figure
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