109 research outputs found
The zCOSMOS 20k Group Catalog
We present an optical group catalog between 0.1 < z < 1 based on 16,500
high-quality spectroscopic redshifts in the completed zCOSMOS-bright survey.
The catalog published herein contains 1498 groups in total and 192 groups with
more than five observed members. The catalog includes both group properties and
the identification of the member galaxies. Based on mock catalogs, the
completeness and purity of groups with three and more members should be both
about 83% with respect to all groups that should have been detectable within
the survey, and more than 75% of the groups should exhibit a one-to-one
correspondence to the "real" groups. Particularly at high redshift, there are
apparently more galaxies in groups in the COSMOS field than expected from mock
catalogs. We detect clear evidence for the growth of cosmic structure over the
last seven billion years in the sense that the fraction of galaxies that are
found in groups (in volume-limited samples) increases significantly with cosmic
time. In the second part of the paper, we develop a method for associating
galaxies that only have photo-z to our spectroscopically identified groups. We
show that this leads to improved definition of group centers, improved
identification of the most massive galaxies in the groups, and improved
identification of central and satellite galaxies, where we define the former to
be galaxies at the minimum of the gravitational potential wells. Subsamples of
centrals and satellites in the groups can be defined with purities up to 80%,
while a straight binary classification of all group and non-group galaxies into
centrals and satellites achieves purities of 85% and 75%, respectively, for the
spectroscopic sample.Comment: 26 pages, 21 figures, published in ApJ (along with machine-readable
tables
A method for the reconstruction of unknown non-monotonic growth functions in the chemostat
We propose an adaptive control law that allows one to identify unstable
steady states of the open-loop system in the single-species chemostat model
without the knowledge of the growth function. We then show how one can use this
control law to trace out (reconstruct) the whole graph of the growth function.
The process of tracing out the graph can be performed either continuously or
step-wise. We present and compare both approaches. Even in the case of two
species in competition, which is not directly accessible with our approach due
to lack of controllability, feedback control improves identifiability of the
non-dominant growth rate.Comment: expansion of ideas from proceedings paper (17 pages, 8 figures),
proceedings paper is version v
The close environment of 24 micron galaxies at 0.6<z<1.0 in the COSMOS field
We investigate the close environment of 203 Spitzer 24 micron-selected
sources at 0.6<z<1.0 using zCOSMOS-bright redshifts and spectra of I<22.5 AB
mag galaxies, over 1.5 sq. deg. of the COSMOS field. We quantify the degree of
passivity of the LIRG and ULIRG environments by analysing the fraction of close
neighbours with Dn(4000)>1.4. We find that LIRGs at 0.6<z<0.8 live in more
passive environments than those of other optical galaxies that have the same
stellar mass distribution. Instead, ULIRGs inhabit more active regions (e.g.
LIRGs and ULIRGs at 0.6<z<0.8 have, respectively, (42.0 +/- 4.9)% and (24.5 +/-
5.9)% of neighbours with Dn (4000)>1.4 within 1 Mpc and +/- 500 km/s). The
contrast between the activities of the close environments of LIRGs and ULIRGs
appears especially enhanced in the COSMOS field density peak at z~0.67, because
LIRGs on this peak have a larger fraction of passive neighbours, while ULIRGs
have as active close environments as those outside the large-scale structure.
The differential environmental activity is related to the differences in the
distributions of stellar mass ratios between LIRGs/ULIRGs and their close
neighbours, as well as in the general local density fields. At 0.8<z<1.0,
instead, we find no differences in the environment densities of ULIRGs and
other similarly massive galaxies, in spite of the differential activities. We
discuss a possible scenario to explain these findings.Comment: ApJ, in press. 9 pages, including 5 figure
Myalgic encephalomyelitis/chronic fatigue Syndrome (ME/CFS) : Investigating care practices pointed out to disparities in diagnosis and treatment across European Union
ME/CFS is a chronic, complex, multisystem disease that often limits the health and functioning of the affected patients. Diagnosing patients with ME/CFS is a challenge, and many different case definitions exist and are used in clinical practice and research. Even after diagnosis, medical treatment is very challenging. Symptom relief and coping may affect how patients live with their disease and their quality of life. There is no consensus on which diagnostic criteria should be used and which treatment strategies can be recommended for patients. The purpose of the current project was to map the landscape of the Euromene countries in respect of national guidelines and recommendations for case definition, diagnosis and clinical approaches for ME/CFS patients. A 23 items questionnaire was sent out by email to the members of Euromene. The form contained questions on existing guidelines for case definitions, treatment/management of the disease, tests and questionnaires applied, and the prioritization of information for data sampling in research. We obtained information from 17 countries. Five countries reported having national guidelines for diagnosis, and five countries reported having guidelines for clinical approaches. For diagnostic purposes, the Fukuda criteria were most often recommended, and also the Canadian Consensus criteria, the International Consensus Criteria and the Oxford criteria were used. A mix of diagnostic criteria was applied within those countries having no guidelines. Many different questionnaires and tests were used for symptom registration and diagnostic investigation. For symptom relief, pain and anti-depressive medication were most often recommended. Cognitive Behavioral Therapy and Graded Exercise treatment were often recommended as disease management and rehabilitative/palliative strategies. The lack of consistency in recommendations across European countries urges the development of regulations, guidance and standards. The results of this study will contribute to the harmonization of diagnostic criteria and treatment for ME/CFS in Europe
The Serologic Screening for Celiac Disease in the General Population (Blood Donors) and in Some High-Risk Groups of Adults (Patients with Autoimmune Diseases, Osteoporosis and Infertility) in the Czech Republic Preliminary Report
ABSTRACT. The prevalence of celiac disease (CD) was determined in healthy blood donors and in highrisk groups of adults (a total of 1835 adults -randomly selected 1312 healthy blood donors, 102 patients with primary osteoporosis, 58 patients with autoimmune diseases and 365 infertile women). It was calculated on the basis of a two-step serologic screening method -in the first step IgA and lgG antigliadin antibodies (AGA) and lgA anti-7-glutamyltransferase ('transglutaminase') antibodies.(ATG) were estimated, in the second step sera positive for lgA AGA and/or lgA ATG were exainined for antiendomysial IgA (AEA) antibodies. Immunoenzymic assay (ELISA) was used for determining of AGA and ATG antibodies; immunoflurescence method, performed on human umbilical cord tissue, was used for assaying of AEA antibodies. Total serum IgA level in only lgG AGA positive subjects was measured by routine turbidimetric method. 0.45 % of healthy blood donors, 0.98 % of osteoporotic patients, 2.7 % of patients suffering from autoimmune disease and 1.13 % of women with infertility considered as immunologically mediated were found to be positive in both steps of serologic screening (AGA and/or ATG and antiendomysium positive). The presumed high prevalence of seropositivity for CD in apparently healthy Czech adult population was confirmed. In the highrisk groups, the prevalence of seropositivity for CD was approximately 2-4 times higher than in healthy blood donors. The real prevalence of CD in the tested groups, however, can be estimated after performing small intestinal biopsy in the seropositive patients. Celiac disease (CD) is an inflammatory disease of the upper small intestine that results from gluten ingestion in susceptible individuals. Intestinal inflammation leads to malabsorption of important nutrients; institution of a gluten-free diet results in mucosal recovery Our knowledge of CD pathogenesis has recently made rapid progress. The disorder is now considered to be the result of a complex interplay of genetic and environmental factors that explain the wide spectrum of clinical manifestations ranging from asymptomatic to severe forms with the consequences of malabsorption. The major mechanism underlying intestinal damage in CD is a ]'-cell driven autoimnmne inflammation, which is triggered by presentation of gluten peptides by HLA-DQ2 and HLA-DQ8 positive antigen presenting cells (Fasano and Catassi 2001). The immune response occurs predominantly in the connective tissue of lamina propria. Tissue 7-glutamyltransferase (EC 2.3.2.13; 'transglutaminase'), which has been identified as one of the highly specific endomysial autoantigens in C
A blind HI survey in the Canes Venatici region
We have carried out a blind HI survey using the Westerbork Synthesis Radio
Telescope to make an inventory of objects with small HI masses (between 10^6
and 10^8 Msol) and to constrain the low-mass end of the HI mass function. The
survey has been conducted in a part of the volume containing the nearby Canes
Venatici groups of galaxies. The surveyed region covers an area on the sky of
about 86 square degrees and a range in velocity from about -450 to about 1330
km/s. We find 70 sources in the survey by applying an automated searching
algorithm. Two of the detections have not been catalogued previously, but they
can be assigned an optical counterpart, based on visual inspection of the
second generation Digital Sky Survey images. Only one of the HI detections is
without an optical counterpart. This object is detected in the vicinity of
NGC4822 and it has been already detected in previous HI studies. Nineteen of
the objects have been detected for the first time in the 21-cm emission line in
this survey. The distribution of the HI properties of our detections confirms
our ability to find low mass objects. 86% of the detections have profile widths
less than 130 km/s and can be considered dwarf galaxy candidates. The HI fluxes
measured imply that this survey goes about 10 times deeper than any previous
blind HI survey. The HI mass function and the optical properties of the
detected sources will be discussed in future papers.Comment: 46 pages, 15 figures (including the atlas of HI observations);
accepted for publication in MNRAS; the high resolution pdf available at
http://www.exp-astro.phys.ethz.ch/kovac/public/WSRTCVn
Genetic Determinants of Age-Related Macular Degeneration in Diverse Populations From the PAGE Study
Substantial progress has been made in identifying susceptibility variants for AMD in European populations; however, few studies have been conducted to understand the role these variants play in AMD risk in diverse populations. The present study aims to examine AMD risk across diverse populations in known and suspected AMD complement factor and lipid-related loci
Modern wolves trace their origin to a late Pleistocene expansion from Beringia
Grey wolves (Canis lupus) are one of the few large terrestrial carnivores that maintained a wide geographic distribution across the Northern Hemisphere throughout the Pleistocene and Holocene. Recent genetic studies have suggested that, despite this continuous presence, major demographic changes occurred in wolf populations between the late Pleistocene and early Holocene, and that extant wolves trace their ancestry to a single late Pleistocene population. Both the geographic origin of this ancestral population and how it became widespread remain a mystery. Here we analyzed a large dataset of novel modern and ancient mitochondrial wolf genomes, spanning the last 50,000 years, using a spatially and temporally explicit modeling framework to show that contemporary wolf populations across the globe trace their ancestry to an expansion from Beringia at the end of the Last Glacial Maximum - a process most likely driven by the significant ecological changes that occurred across the Northern Hemisphere during this period. This study provides direct ancient genetic evidence that long-range migration has played an important role in the population history of a large carnivore and provides an insight into how wolves survived the wave of megafaunal extinctions at the end of the last glaciation. Moreover, because late Pleistocene grey wolves were the likely source from which all modern dogs trace their origins, the demographic history described in this study has fundamental implications for understanding the geographical origin of the dog
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