924 research outputs found
Similarity classes of 3x3 matrices over a local principal ideal ring
In this paper similarity classes of three by three matrices over a local
principal ideal commutative ring are analyzed. When the residue field is
finite, a generating function for the number of similarity classes for all
finite quotients of the ring is computed explicitly.Comment: 14 pages, final version, to appear in Communications in Algebr
Automated multi-day tracking of marked mice for the analysis of social behaviour
A quantitative description of animal social behaviour is informative for behavioural biologists and clinicians developing drugs to treat social disorders. Social interaction in a group of animals has been difficult to measure because behaviour develops over long periods of time and requires tedious manual scoring, which is subjective and often non-reproducible. Computer-vision systems with the ability to measure complex social behaviour automatically would have a transformative impact on biology. Here, we present a method for tracking group-housed mice individually as they freely interact over multiple days. Each mouse is bleach-marked with a unique fur pattern. The patterns are automatically learned by the tracking software and used to infer identities. Trajectories are analysed to measure behaviour as it develops over days, beyond the range of acute experiments. We demonstrate how our system may be used to study the development of place preferences, associations and social relationships by tracking four mice continuously for five days. Our system enables accurate and reproducible characterisation of wild-type mouse social behaviour and paves the way for high-throughput long-term observation of the effects of genetic, pharmacological and environmental manipulations
Sociohydrodynamics: data-driven modelling of social behavior
Living systems display complex behaviors driven not only by physical forces,
but also decision-making guided by information processing and molded by
cultural and/or biological evolution. Hydrodynamic theories hold promise for
simplified, universal descriptions of these collective behaviors. However,
incorporating the individual preferences of decision-making organisms into a
hydrodynamic theory is an open problem. Here, we develop a data-driven pipeline
that links micromotives to macrobehavior by augmenting hydrodynamics with
utility functions that describe individual preferences in microeconomics. We
show how to systematically validate the hypotheses underlying this construction
from data using statistical tools based on neural networks. We illustrate this
pipeline on the case study of human residential dynamics in the United States,
for which census and sociological data is available, and show how trends in
sociological surveys can be related to trends seen in racial segregation. In
particular, we highlight that a history-dependence in the
segregation-integration transition can arise even when agents have no memory.
Beyond residential segregation, our work paves the way for systematic
investigations of social-driven motility in real space from micro-organisms to
humans, as well as fitness-mediated motion in more abstract genomic spaces
The first joint ESGAR/ ESPR consensus statement on the technical performance of cross-sectional small bowel and colonic imaging
Objectives: To develop guidelines describing a standardised approach to patient preparation and acquisition protocols for magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US) of the small bowel and colon, with an emphasis on imaging inflammatory bowel disease. Methods: An expert consensus committee of 13 members from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) and European Society of Paediatric Radiology (ESPR) undertook a six-stage modified Delphi process, including a detailed literature review, to create a series of consensus statements concerning patient preparation, imaging hardware and image acquisition protocols. Results: One hundred and fifty-seven statements were scored for agreement by the panel of which 129 statements (82 %) achieved immediate consensus with a further 19 (12 %) achieving consensus after appropriate modification. Nine (6 %) statements were rejected as consensus could not be reached. Conclusions: These expert consensus recommendations can be used to help guide cross-sectional radiological practice for imaging the small bowel and colon. Key points: • Cross-sectional imaging is increasingly used to evaluate the bowel • Image quality is paramount to achieving high diagnostic accuracy • Guidelines concerning patient preparation and image acquisition protocols are provided
How are deep soils responding to warming?
Scientists aim to integrate observations from deep-soil-warming experiments worldwide to better understand how ecosystems vital to food security and environmental health will react to climate change
K-band luminosity (mass) segregation in AC118 at z=0.31
Using new observations of the galaxy cluster A118 at intermediate redshift
(z=0.31) in the Ks band, we were able to detect the cluster from the center to
half the Abell radius (1.5 Mpc, Ho=50 km/s/Mpc) and possibly to 2.0 Mpc. The
analysis of both the spatial distribution of galaxies of various luminosities
and of the luminosity function (LF) of galaxies in different cluster locations
strongly confirms and extends to larger clustercentric radii the luminosity
segregation found in a previous analysis of this cluster restricted to a
smaller cluster area: there is an excess of bright galaxies in the cluster core
(inside 250 Kpc) or a deficit of dwarfs in the remain part of the cluster.
Outside the cluster core and as far as 1.5 or even 2 Mpc, the giant-to-dwarf
ratio is constant. Because of the luminosity segregation, the LF of the AC118
shows a larger number of bright galaxies per unit dwarf in the core than in
other cluster locations. All non-core LFs, computed at several cluster
locations, are compatible each other. These results hold both including or
excluding the galaxies located in an overdensity found in the far South of
AC118 and in the second clump in galaxy density at the cluster North-West.
Since the near-infrared emission is a good tracer of the stellar mass, we
interpret the segregation found as a mass segregation.Comment: A&A in pres
The enrichment history of the intracluster medium: a Bayesian approach
This work measures the evolution of the iron content in galaxy clusters by a
rigorous analysis of the data of 130 clusters at 0.1<z<1.3. This task is made
difficult by a) the low signal-to-noise ratio of abundance measurements and the
upper limits, b) possible selection effects, c) boundaries in the parameter
space, d) non-Gaussian errors, e) the intrinsic variety of the objects studied,
and f) abundance systematics. We introduce a Bayesian model to address all
these issues at the same time, thus allowing cross-talk (covariance). On
simulated data, the Bayesian fit recovers the input enrichment history, unlike
in standard analysis. After accounting for a possible dependence on X-ray
temperature, for metal abundance systematics, and for the intrinsic variety of
studied objects, we found that the present-day metal content is not reached
either at high or at low redshifts, but gradually over time: iron abundance
increases by a factor 1.5 in the 7 Gyr sampled by the data. Therefore, feedback
in metal abundance does not end at high redshift. Evolution is established with
a moderate amount of evidence, 19 to 1 odds against faster or slower metal
enrichment histories. We quantify, for the first time, the intrinsic spread in
metal abundance, 18+/-3 %, after correcting for the effect of evolution, X-ray
temperature, and metal abundance systematics. Finally, we also present an
analytic approximation of the X-ray temperature and metal abundance likelihood
functions, which are useful for other regression fitting involving these
parameters. The data for the 130 clusters and code used for the stochastic
computation are provided with the paper.Comment: A&A, in pres
The number counts, luminosity functions and evolution of microwave-selected (WMAP) blazars and radio galaxies
(Abridged) We carried out an extensive search to identify the counterparts of
all the sources listed in the WMAP 3-yr catalogue using literature and archival
data. Our work led to the identification of 309 WMAP sources, 98% of which are
blazars, radio quasars or radio galaxies. At present, 15 objects still remain
without identification due to the lack of optical spectroscopic data or a clear
radio counterpart. Our results allow us to define a flux limited sample of 203
high Galactic latitude microwave sources ( Jy, ) which is virtually completely identified (99%). The microwave band
is ideally suited for blazar statistical studies since this is the part of the
em spectrum that is least affected by the superposition of spectral components
of different origin. Using this data-set we derived number counts, luminosity
functions and cosmological evolution of blazars and radio galaxies at microwave
frequencies. Our results are in good agreement with those found at radio
frequencies. The 5 GHz bivariate blazar luminosity functions are similar to
those derived from the DXRBS survey, which shows that this sample is
representative of the blazar population at 41 GHz. Microwave selected broad-
lined quasars are about 6 times more abundant than BL Lacs, a ratio that is
similar to, or larger than, that seen at radio and gamma-ray frequencies, once
spectral selection effects are taken into account. This strongly suggests that
the mechanism responsible for the generation of gamma-rays is, at first order,
the same in all blazar types. Our results confirm the findings of Giommi &
Colafrancesco (2004, 2006) that blazars and radio galaxies are the largest
contaminants of the CMB anisotropy maps. We predict that these sources are also
bright gamma-ray sources, most of which will be detected by AGILE and FERMI.Comment: 18 pages, 11 figures, 3 tables. A&A in pres
Histopathological study of endometrial biopsy in infertility: A cross sectional study in a teaching hospital
Background: Endometrium is dynamic tissue which responds to hormones hence is the most sensitive indicator of ovarian function. Uterine pathology and cervical pathology like chronic infections or quality of cervical mucus plays a role in failure of conception. Hence endometrial biopsy is one of the most important investigations in infertility. Aim and Objectives: To document the morphological changes seen in endometrial biopsies and their demographic distribution in patients with infertility. Secondly to examine cervico-vaginal pap smear changes in infertility cases. Material and Methods: The study is a prospective cross-sectional study carried out during the period of June 2018 to July 2020. Married women visiting infertility clinic, who have undergone endometrial biopsy as an infertility evaluation were included in the study. Informed consent for the procedure was taken. Only premenstrual endometrial biopsy was included and inadequate biopsy samples were excluded from the study. Cervico-vaginal pap smear of these cases was processed under liquid-based cytology and reported using Bethesda system for cervical cytology. The histopathological findings and pap smear findings were statistically analyzed. Results: Ten percent of endometrial biopsies were indicated in evaluation of infertility among all biopsy registries. Primary infertility accounted 64% and secondary infertility as 36%. Sixty-six cases of endometrial biopsy were studied during study period. The most common histopathological findings were secretory endometrium, followed by proliferative (anovulatory and 2 cases luteal phase defect) endometrium, progestin induced changes, endometrial polyps, chronic endometritis and benign hyperplasia. Seventy-seven percentage of pap smears were negative for intraepithelial lesions (no squamous or endocervical abnormalities), predominantly showing signs of cervicitis and bacterial vaginitis. Conclusion: Histopathological study of endometrium forms an important, safe and cheaper diagnostic tool. Uterine pathology contributes to major pathogenesis of infertility and thus endometrial biopsy plays a significant role in preliminary evaluation of cases with infertility
- …