The reconstructed residual error: a novel segmentation evaluation measure for reconstructed images in tomography

In this paper, we present the reconstructed residual error, which evaluates the quality of a given segmentation of a reconstructed image in tomography. This novel evaluation method, which is independent of the methods that were used to reconstruct and segment the image, is applicable to segmentations that are based on the density of the scanned object. It provides a spatial map of the errors in the segmented image, based on the projection data. The reconstructed residual error is a reconstruction of the difference between the recorded data and the forward projection of that segmented image. The properties and applications of the algorithm are v

Exactly solvable path integral for open cavities in terms of quasinormal modes

We evaluate the finite-temperature Euclidean phase-space path integral for the generating functional of a scalar field inside a leaky cavity. Provided the source is confined to the cavity, one can first of all integrate out the fields on the outside to obtain an effective action for the cavity alone. Subsequently, one uses an expansion of the cavity field in terms of its quasinormal modes (QNMs)-the exact, exponentially damped eigenstates of the classical evolution operator, which previously have been shown to be complete for a large class of models. Dissipation causes the effective cavity action to be nondiagonal in the QNM basis. The inversion of this action matrix inherent in the Gaussian path integral to obtain the generating functional is therefore nontrivial, but can be accomplished by invoking a novel QNM sum rule. The results are consistent with those obtained previously using canonical quantization.Comment: REVTeX, 26 pages, submitted to Phys. Rev.

Unique reproduction system of invasive ants avoids genetic bottlenecks

INTRODUCTION: Advanced glycation endproducts (AGEs) may be involved in the development of atherosclerosis, beyond diabetes and renal disease. Skin autofluorescence (AF) is a non-invasive marker for AGEs. We examined whether skin AF is increased in (subclinical) atherosclerosis and associated with the degree of atherosclerosis independent of diabetes and renal function. METHODS: A cross-sectional study of 223 patients referred for primary (n = 163) or secondary (n = 60) prevention between 2006 and 2012 was performed. Skin AF was measured using the AGE-Reader. Ultrasonography was used to assess plaques in carotid and femoral arteries and computed tomography for the calculation of the coronary artery calcium score (CACS; in primary prevention only). Primary prevention patients were divided into a group with subclinical atherosclerosis defined as >1 plaque or CACS>100 (n = 67; age 53 year [interquartile range 48-56]; 49% male) and without (controls; 96; 43 [38-51]; 55%). Secondary prevention were patients with peripheral arterial disease (60; 64 [58-70]; 73%). RESULTS: Skin AF was higher in subclinical and clinical atherosclerosis compared with controls (skin AF 2.11 [interquartile range 1.83-2.46] and 2.71 [2.15-3.27] vs. 1.87 [1.68-2.12] respectively; P = 0.005 and <0.001). In a multivariate analysis, the association of skin AF with the atherosclerosis categories was independent of age, sex, diabetes, presence of the metabolic syndrome, Framingham Risk Score, and renal function. Skin AF correlated with most cardiovascular risk factors, Framingham risk score, and IMT and CACS. CONCLUSIONS: Skin AF is increased in documented subclinical and clinical atherosclerosis, independent of known risk factors such as diabetes and renal disease. These data suggest that AGEs may be associated with the burden of atherosclerosis and warrant a prospective study to investigate its clinical usability as a risk assessment tool for primary prevention

Assessing publication rates from medical students' mandatory research projects in the Netherlands: a follow-up study of 10 cohorts of medical students

Objectives The medical field is facing a clinician-scientist shortage. Medical schools could foster the clinician-scientist workforce by offering students research opportunities. Most medical schools offer elective research programmes. Subsequently, a subset of doctors graduates without any research experience. Mandatory research projects may be more sufficient to develop clinician-scientist, but take more supervision and curricular time. There is limited insight in the scientific outcomes of mandatory research experiences. This study aims to examine publication rates of a mandatory research experience, identify factors associated with publication, and includes postgraduate research engagement. Design and setting Prospective follow-up study involving 10 cohorts of medical students' mandatory research projects from Leiden University Medical Center. Participants All medical students who conducted their research project between 2008 and 2018 (n=2329) were included. Main outcome measure Publication rates were defined as peer-reviewed scientific publications, including research papers, reviews, and published meeting abstracts. Postgraduate research engagement was defined as research participation and dissemination of research at scientific conferences or in journals. Results In total, 644 (27.7%) of all mandatory research experiences resulted in publication, with students mainly as first (n=984, 42.5%) or second author (n=587, 25.3%) and above world average citation impact (mean normalised journal score 1.29, mean normalised citation score 1.23). Students who conducted their research in an academic centre (adjusted OR 2.82; 95% CI 2.10 to 3.77), extended their research (adjusted OR 1.73; 95% CI 1.35 to 2.20), were involved in an excellency track (adjusted OR 2.08; 95% CI 1.44 to 3.01), or conducted clinical (adjusted OR 2.08; 95% CI 1.15 to 3.74) or laboratory (adjusted OR 2.16; 95% CI 1.16 to 4.01) research published their research more often. Later as junior doctors, this group significantly more often disseminate their research results at scientific conferences (adjusted OR 1.89; 95% CI 1.11 to 3.23) or in journals (adjusted OR 1.98; 95% CI 1.14 to 3.43). Conclusions Our findings suggest that a significant subset of hands-on mandatory research projects with flexible learning pathways result in tangible research output with proper impact and that such successful experiences can be considered as diving board towards a research-oriented career.Clinical epidemiolog

Vitamin D in relation to myocardial structure and function after eight years of follow-up: the Hoorn study.

Background and Aims: To investigate associations between baseline serum 25-hydroxyvitamin D [25(OH)D] levels and myocardial structure and function after 8 years of follow-up in older Dutch subjects. Methods: We included 256 subjects of the Hoorn Study, a population-based cohort. They underwent a standardized 2-dimensional echocardiogram at baseline between 2000 and 2001, and again between 2007 and 2009. We studied the association of 25(OH)D quartiles with echocardiographic measures of the left ventricular mass index (LVMI), left ventricular systolic function and markers of diastolic function using linear regression analyses. Results: At baseline, subjects had a mean age of 67.4 ± 5.2 years and 41.4% had prior cardiovascular disease (CVD). Low serum 25(OH)D levels were only associated with higher LVMI at 8-year follow-up in subjects without prior CVD and in subjects with low kidney function (median estimated glomerular filtration rate ≤77.5 ml/min/1.73

Divination: Exemplifying and Configuring Archetypes in Ceramics

Abstract/Summary Dissertation Divination: Exemplifying and Configuring Archetypes in Ceramics is a study of my research practice. The cards of the tarot can be used as a conceptual framework and source of inspiration for making ceramic sculptures. The cards can be used to understand the creative process as an expression of archetypes. My dissertation discusses these archetypes from the tarot cards, both in their historical operation, their manifestation in my art practice, as well as, examining approaches taken to these archetypes by other artists such as Salvador Dali and Niki de Saint Phalle. The theoretical basis for the dissertation is informed by the writings of Carl G. Jung who has proposed concepts dealing with creativity, coincidence, a collective unconscious and archetypes. These ideas form a model for the understanding of my studio work. As background, the dissertation examines examples of artworks that could be seen to be drawn from a collective unconscious. Studio Work The studio work consists of a series of ceramic sculptures formulating the archetypes that I have derived from the tarot cards. The three dimensional clay, with found inclusions, examines the idea of specific archetypes. These archetypes are titled in the works including: The Fool, Strength, The Magician, Tarot Sun, The Empress II, The Lovers, Empress l, The Chariot I and II The Angel Temperance, The Tarot Devil and The World. The ceramic objects have been created in clay using handbuilding techniques. The clay was such that it could include found ceramic pieces and be refired. The pieces have been re-fired many times to achieve a variety of glaze effects. The works range in size from 30-60 cms approximately and include freestanding sculptures and complementing flat wall works

Common and rare variant association analyses in amyotrophic lateral sclerosis identify 15 risk loci with distinct genetic architectures and neuron-specific biology

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a lifetime risk of one in 350 people and an unmet need for disease-modifying therapies. We conducted a cross-ancestry genome-wide association study (GWAS) including 29,612 patients with ALS and 122,656 controls, which identified 15 risk loci. When combined with 8,953 individuals with whole-genome sequencing (6,538 patients, 2,415 controls) and a large cortex-derived expression quantitative trait locus (eQTL) dataset (MetaBrain), analyses revealed locus-specific genetic architectures in which we prioritized genes either through rare variants, short tandem repeats or regulatory effects. ALS-associated risk loci were shared with multiple traits within the neurodegenerative spectrum but with distinct enrichment patterns across brain regions and cell types. Of the environmental and lifestyle risk factors obtained from the literature, Mendelian randomization analyses indicated a causal role for high cholesterol levels. The combination of all ALS-associated signals reveals a role for perturbations in vesicle-mediated transport and autophagy and provides evidence for cell-autonomous disease initiation in glutamatergic neurons

Associations of autozygosity with a broad range of human phenotypes

In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (F-ROH) for >1.4 million individuals, we show that F-ROH is significantly associated (p <0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: F-ROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44-66%] in the odds of having children. Finally, the effects of F-ROH are confirmed within full-sibling pairs, where the variation in F-ROH is independent of all environmental confounding.Peer reviewe