1,234 research outputs found
An Atlas of the circumnuclear regions of 75 Seyfert galaxies in the near-UV with HST Advanced Camera for Surveys
We present an atlas of the central regions of 75 Seyfert galaxies imaged in
the near-UV with the Advanced Camera for Surveys of the Hubble Space Telescope
at an average resolution of ~10pc. These data complement archival high
resolution data from the Space Telescope at optical and near-IR wavelengths,
creating an extremely valuable dataset for astronomers with a broad range of
scientific interests. Our goal is to investigate the nature of the near-UV
light in these objects, its relation to the circumnuclear starburst phenomenon,
and the connection of this to the evolution and growth of the galaxy bulge and
central black hole. In this paper, we describe the near-UV morphology of the
objects and characterize the near-UV emission. We estimate the size and the
luminosity of the emitting regions and extract the luminosity profile. We also
determine the presence of unresolved compact nuclei. In addition, the
circumnuclear stellar cluster population is identified, and the contribution of
the stellar clusters to the total light, at this wavelength, is estimated. The
size of the sample allows us to draw robust statistical conclusions. We find
that {Seyfert 1} galaxies are completely dominated by its bright and compact
nucleus, that remains point-like at this resolution, while we find almost no
unresolved nucleus in Seyfert 2. The Seyfert types 1 and 2 are quite segregated
in an asymmetry vs compactness plot. Stellar clusters are found somewhat more
frequently in Sy2 (in ~70% of the galaxies) than in Sy1 (~57%), and contribute
more to the total light in Sy2, but this two differences seem to be mostly due
to the large contribution of the compact nucleus in Sy1, as the luminosity
distribution of the clusters is similar in both Sy types.Comment: Accepted for publication in AJ, 58 pages, 20 figures. High-resolution
figures for all the objects are available at
http://www.iaa.es/~manuel/publications/paper01.htm
Capsule endoscopy interpretation: the role of physician extenders
Background and aims: capsule endoscopy (CE) allows for a
new era in small-bowel examination. Nevertheless, physicians’
time for CE-interpretation remains longer than desirable. Alternative
strategies to physicians have not been widely investigated.
The aim of this study was to evaluate the accuracy of physician
extenders in CE-interpretation.
Material and methods: one CE-experienced gastroenterologist
and two physician extenders reviewed independently 20 CEprocedures.
Each reader was blinded to the findings of their colleagues.
A consensus formed by the readers and a second
CE-experienced gastroenterologist was used as gold standard.
Number, type and location of images selected, character of CEexams
and their relationship with indications were recorded. Gastric
emptying time (GEt), small-bowel transit time (SBTt) and time
spent by readers were also noted.
Results: sensitivity and specificity for “overall” lesions was 79
and 99% for the gastroenterologist; 86 and 43% for the nurse;
and 80 and 57% for the resident. All 34 “major” lesions considered
by consensus were found by the readers. Agreement between
consensus and readers for images classification and procedures
interpretation was good to excellent (Îş from 0.55 to 1). No
significant differences were found in the GEt and SBTt obtained
by consensus and readers. The gastroenterologist was faster than
physician extenders (mean time spent was 51.9 ± 13.5 minutes
versus 62.2 ± 19 and 60.9 ± 17.1 for nurse and resident, respectively;
p < 0.05).
Conclusions: physician extenders could be the perfect complement
to gastroenterologists for CE-interpretation but gastroenterologists
should supervise their findings. Future cost-efficacy
analyses are required to assess the benefits of this alternative
Matching microscopic and macroscopic responses in glasses
We first reproduce on the Janus and Janus II computers a milestone experiment
that measures the spin-glass coherence length through the lowering of
free-energy barriers induced by the Zeeman effect. Secondly we determine the
scaling behavior that allows a quantitative analysis of a new experiment
reported in the companion Letter [S. Guchhait and R. Orbach, Phys. Rev. Lett.
118, 157203 (2017)]. The value of the coherence length estimated through the
analysis of microscopic correlation functions turns out to be quantitatively
consistent with its measurement through macroscopic response functions.
Further, non-linear susceptibilities, recently measured in glass-forming
liquids, scale as powers of the same microscopic length.Comment: 6 pages, 4 figure
The Mpemba effect in spin glasses is a persistent memory effect
The Mpemba effect occurs when a hot system cools faster than an initially
colder one, when both are refrigerated in the same thermal reservoir. Using the
custom built supercomputer Janus II, we study the Mpemba effect in spin glasses
and show that it is a non-equilibrium process, governed by the coherence length
\xi of the system. The effect occurs when the bath temperature lies in the
glassy phase, but it is not necessary for the thermal protocol to cross the
critical temperature. In fact, the Mpemba effect follows from a strong
relationship between the internal energy and \xi that turns out to be a
sure-tell sign of being in the glassy phase. Thus, the Mpemba effect presents
itself as an intriguing new avenue for the experimental study of the coherence
length in supercooled liquids and other glass formers.Comment: Version accepted for publication in PNAS. 6 pages, 7 figure
The Spin Glass Phase in the Four-State, Three-Dimensional Potts Model
We perform numerical simulations, including parallel tempering, on the Potts
glass model with binary random quenched couplings using the JANUS
application-oriented computer. We find and characterize a glassy transition,
estimating the location of the transition and the value of the critical
exponents. We show that there is no ferromagnetic transition in a large
temperature range around the glassy critical temperature. We also compare our
results with those obtained recently on the "random permutation" Potts glass.Comment: 7 pages and 3 figures. Corrected minor typo
An in-depth view of the microscopic dynamics of Ising spin glasses at fixed temperature
Using the dedicated computer Janus, we follow the nonequilibrium dynamics of
the Ising spin glass in three dimensions for eleven orders of magnitude. The
use of integral estimators for the coherence and correlation lengths allows us
to study dynamic heterogeneities and the presence of a replicon mode and to
obtain safe bounds on the Edwards-Anderson order parameter below the critical
temperature. We obtain good agreement with experimental determinations of the
temperature-dependent decay exponents for the thermoremanent magnetization.
This magnitude is observed to scale with the much harder to measure coherence
length, a potentially useful result for experimentalists. The exponents for
energy relaxation display a linear dependence on temperature and reasonable
extrapolations to the critical point. We conclude examining the time growth of
the coherence length, with a comparison of critical and activated dynamics.Comment: 38 pages, 26 figure
Are anti-ganglioside antibodies detectable in serum from patients with critical illness myopathy and polyneuropathy?
Introduction: Critical illness myopathy (CIM) and polyneuropathy (CIP) are the most common cause of acquired weakness in intensive care units (ICU). However, its exact pathogenesis remains unclear. Abnormal excitability of muscle due to a sodium channelopathy is one of the mechanisms proposed. The aim of this study is to test for the presence of anti-ganglioside antibodies in serum from patients with CIM or both combined CIM/CIP, since there is evidence that they can cause reversible dysfunction of voltage-gated sodium channels.Methods: In a prospective way, we studied 35 patients admitted in ICU by weekly EMG. When positive spontaneous activity (PSA) was detected, a muscle biopsy was performed. Twenty patients met criteria of CIM; five of them also developed overlapping CIP. We did not detect any kind of abnormality in 10 patients during the follow up period. Sera were analyzed for the presence of anti-ganglioside antibodies (Ganglioside-profile 2 Euroline, Euroimmun). Results: Overall, positive reactivity against anti-GT1b was found in one patient with CIM, representing 2.8% (1/35) of the total sample.Conclusion: Reduced percentage of patients affected of CIM or CIM/CIP exhibits positive reactive against anti-ganglioside antibodies. Thus, it could be suggested they do not play a primary role in their pathogenesis. Key words: Critical illness myopathy, critical illness polineuropathy, difficult weaning, channelopathy, muscle fiber inexcitability, anti-ganglioside antibodies  DOI: http://dx.doi.org/10.17268/rmt.2020.v15i01.0
Incident cervical HPV infections in young women: Transition probabilities for CIN and infection clearance
Background: We describe transition probabilities for incident human papillomavirus (HPV) 16/18/31/33/35/45/52/58/59 infections and cervical intraepithelial neoplasia (CIN) 1 lesions. Methods: Women ages 16 to 23 years underwent cytology and cervical swab PCR testing for HPV at approximately 6-month intervals for up to 4 years in the placebo arm of an HPV vaccine trial. The cumulative proportion of incident HPV infections with diagnosed CIN, clearing (infection undetectable), or persisting without CIN, were estimated. Results: Most incident infections cleared, without detection of CIN, ranging at 36 months from 66.9% for HPV31 to 91.1% for HPV59. There was little variation in the 36-month proportion of incident HPV16, 18, and 31 infections followed by a CIN1 lesion positive for the relevant HPV type (range 16.7%-18.6%), with lower risks for HPV59 (6.4%) and HPV33 (2.9%). Thirty-six-month transition probabilities for CIN2 ranged across types from 2.2% to 9.1%; however, the number of events was generally too small for statistically significant differences to be seen across types for this endpoint, or CIN3. Conclusions: Some incident HPV types appear more likely to result in diagnosed CIN1 than others. The relative predominance of HPV16, vis-à -vis some other high-risk HPV types (e.g., HPV33) in prevalent CIN2/3, appears more directly associated with relatively greater frequency of incident HPV16 infections within the population, than a higher risk of infection progression to CIN2/3. Impact: Nearly all incident HPV infections either manifest as detectable CIN or become undetectable within 36 months. Some HPV types (e.g., 16 and 33) appear to have similar risk of CIN2/3 despite widely varied incidence. ©2011 AACR
Critical parameters of the three-dimensional Ising spin glass
We report a high-precision finite-size scaling study of the critical behavior
of the three-dimensional Ising Edwards-Anderson model (the Ising spin glass).
We have thermalized lattices up to L=40 using the Janus dedicated computer. Our
analysis takes into account leading-order corrections to scaling. We obtain Tc
= 1.1019(29) for the critical temperature, \nu = 2.562(42) for the thermal
exponent, \eta = -0.3900(36) for the anomalous dimension and \omega = 1.12(10)
for the exponent of the leading corrections to scaling. Standard (hyper)scaling
relations yield \alpha = -5.69(13), \beta = 0.782(10) and \gamma = 6.13(11). We
also compute several universal quantities at Tc.Comment: 9 pages, 5 figure
DetecciĂłn y seguimiento de objetos en vĂdeos de actividades de vida diaria para rehabilitaciĂłn de pacientes con daño cerebral adquirido
Las tĂ©cnicas de rehabilitaciĂłn permiten la recuperaciĂłn y mejora de las funciones dañadas o deterioradas y ayuda al paciente con DCA a adaptarse a su nueva situaciĂłn. El avance tecnolĂłgico que se ha producido en las Ăşltimas dĂ©cadas, ha impulsado la investigaciĂłn en el diseño y desarrollo de nuevos modelos de rehabilitaciĂłn. La tecnologĂa de vĂdeo interactivo se convierte en un elemento de apoyo en estos nuevos modelos rehabilitadores. Se hace necesario desarrollar nuevos algoritmos de segmentaciĂłn y seguimiento que permitan dotar de informaciĂłn adicional a los vĂdeos. En este trabajo se han implementado y evaluado dos mĂ©todos que permiten realizar la detecciĂłn y el seguimiento de objetos de interĂ©s
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