134 research outputs found
The phase diagram of L\'evy spin glasses
We study the L\'evy spin-glass model with the replica and the cavity method.
In this model each spin interacts through a finite number of strong bonds and
an infinite number of weak bonds. This hybrid behaviour of L\'evy spin glasses
becomes transparent in our solution: the local field contains a part
propagating along a backbone of strong bonds and a Gaussian noise term due to
weak bonds. Our method allows to determine the complete replica symmetric phase
diagram, the replica symmetry breaking line and the entropy. The results are
compared with simulations and previous calculations using a Gaussian ansatz for
the distribution of fields.Comment: 20 pages, 7 figure
As redes sociais na internet e suas apropriaçÔes por jovens brasileiros e portugueses em idade escolar
O fenĂŽmeno das redes sociais on-line Ă© marcante na atual fase da
internet 2.0, tendo crescido vertiginosamente, a partir do ano 2005, com
a adesĂŁo majoritĂĄria de jovens, que as acessam por computadores fixos e
mĂłveis, em plataformas dos mais variados tipos. Por meio delas, trocam
mensagens e compartilham conteĂșdos os mais diversos. Diante desse
cenĂĄrio, com base em duas pesquisas convergentes, pretende-se discutir
os usos e as apropriaçÔes das redes sociais on-line por jovens alunos do
ensino fundamental e médio e destacar os pontos mais pertinentes da
atual fase da internet nos contextos pessoal, familiar e escolar. Foram
aplicados questionĂĄrios, inspirados em modelo de pesquisa elaborado na
ItĂĄlia, a 404 alunos brasileiros de oito escolas no Rio de Janeiro e a 549
alunos portugueses de 11 escolas na regiĂŁo portuguesa de Castelo Branco.
Com essa rica empiria, verificou-se em que pontos os jovens se aproximam
dos ideais de uma nova subjetividade (o leitor imerso nas novas mĂdias) e
de um jovem naturalmente afeito aos suportes digitais (o nativo digital).The phenomenon of online social networks has been remarkable in the
current phase of internet 2.0 and has grown rapidly from the year 2005, with
the majority membership of young people, who access the social networks
from desktops and mobile platforms of all kinds. Using these platforms,
they exchange messages and share various contents. Given this scenario,
based on two converging researches, this paper discusses the uses and
appropriations of online social networks by students of elementary school
and high school. Also, it highlights the most relevant points in the current
phase of the internet in relation to personal, family and school contexts.
Inspired by a research model developed in Italy, 404 questionnaires were
applied to Brazilian students from eight schools in Rio de Janeiro and 549
Portuguese students from 11 schools in the Portuguese region of Castelo
Branco. With this comprehensive database, we could verify at which
points the youth approaches the ideals of a new subjectivity (the reader
immersed in new medias) and a youngster naturally used to digital media
(the digital native).info:eu-repo/semantics/publishedVersio
The use of Macitentan in Fontan circulation: a case report.
BACKGROUND: The Fontan circulation, a result of a palliative procedure in patients with single systemic ventricles, is defined by chronically elevated pulmonary vascular resistance. When traditional heart failure therapies fail, pharmacological agents that reduce pulmonary artery pressures may be used. These include endothelial-receptor antagonists, prostanoids and phosphodiesterase type 5 inhibitors. We report the first use of macitentan, an endothelin-receptor antagonist, in a patient with a Fontan circulation. CASE PRESENTATION: We describe the case of a 50Â year old female with tricuspid atresia and transposition of the great arteries. Following complex surgery as a child, she subsequently underwent a fenestrated modified atrial pulmonary Fontan operation which was later converted to a total cavopulmonary anastomosis Fontan circulation. Due to failure of various medications to relieve her worsening symptoms, she was commenced on macitentan in April 2016. Few months later, she demonstrated a significant symptomatic improvement and associated increase in her incremental shuttle walking test distance. CONCLUSIONS: Macitentan has slower receptor dissociation kinetics compared to other endothelin-receptor antagonists, leading to enhanced pharmacological activity with promising effects in patients with pulmonary arterial hypertension. The patient we report has shown considerable improvement in exercise capacity following introduction of this medication and thus we suggest further randomised trials to establish the role of different endothelin-receptor antagonists in the management of the Fontan circulation
Quantized vortices and superflow in arbitrary dimensions: Structure, energetics and dynamics
The structure and energetics of superflow around quantized vortices, and the
motion inherited by these vortices from this superflow, are explored in the
general setting of the superfluidity of helium-four in arbitrary dimensions.
The vortices may be idealized as objects of co-dimension two, such as
one-dimensional loops and two-dimensional closed surfaces, respectively, in the
cases of three- and four-dimensional superfluidity. By using the analogy
between vorticial superflow and Ampere-Maxwell magnetostatics, the equilibrium
superflow containing any specified collection of vortices is constructed. The
energy of the superflow is found to take on a simple form for vortices that are
smooth and asymptotically large, compared with the vortex core size. The motion
of vortices is analyzed in general, as well as for the special cases of
hyper-spherical and weakly distorted hyper-planar vortices. In all dimensions,
vortex motion reflects vortex geometry. In dimension four and higher, this
includes not only extrinsic but also intrinsic aspects of the vortex shape,
which enter via the first and second fundamental forms of classical geometry.
For hyper-spherical vortices, which generalize the vortex rings of three
dimensional superfluidity, the energy-momentum relation is determined. Simple
scaling arguments recover the essential features of these results, up to
numerical and logarithmic factors.Comment: 35 pages, 7 figure
Quantum Criticality in Heavy Fermion Metals
Quantum criticality describes the collective fluctuations of matter
undergoing a second-order phase transition at zero temperature. Heavy fermion
metals have in recent years emerged as prototypical systems to study quantum
critical points. There have been considerable efforts, both experimental and
theoretical, which use these magnetic systems to address problems that are
central to the broad understanding of strongly correlated quantum matter. Here,
we summarize some of the basic issues, including i) the extent to which the
quantum criticality in heavy fermion metals goes beyond the standard theory of
order-parameter fluctuations, ii) the nature of the Kondo effect in the quantum
critical regime, iii) the non-Fermi liquid phenomena that accompany quantum
criticality, and iv) the interplay between quantum criticality and
unconventional superconductivity.Comment: (v2) 39 pages, 8 figures; shortened per the editorial mandate; to
appear in Nature Physics. (v1) 43 pages, 8 figures; Non-technical review
article, intended for general readers; the discussion part contains more
specialized topic
Parity-related molecular signatures and breast cancer subtypes by estrogen receptor status
INTRODUCTION: Relationships of parity with breast cancer risk are complex. Parity is associated with decreased risk of postmenopausal hormone receptorâpositive breast tumors, but may increase risk for basal-like breast cancers and early-onset tumors. Characterizing parity-related gene expression patterns in normal breast and breast tumor tissues may improve understanding of the biological mechanisms underlying this complex pattern of risk. METHODS: We developed a parity signature by analyzing microRNA microarray data from 130 reduction mammoplasty (RM) patients (54 nulliparous and 76 parous). This parity signature, together with published parity signatures, was evaluated in gene expression data from 150 paired tumors and adjacent benign breast tissues from the Polish Breast Cancer Study, both overall and by tumor estrogen receptor (ER) status. RESULTS: We identified 251 genes significantly upregulated by parity status in RM patients (parous versus nulliparous; false discovery rateâ=â0.008), including genes in immune, inflammation and wound response pathways. This parity signature was significantly enriched in normal and tumor tissues of parous breast cancer patients, specifically in ER-positive tumors. CONCLUSIONS: Our data corroborate epidemiologic data, suggesting that the etiology and pathogenesis of breast cancers vary by ER status, which may have implications for developing prevention strategies for these tumors
Discovery of a z = 0.65 post-starburst BAL quasar in the DES supernova fields
We present the discovery of a z = 0.65 low-ionization broad absorption line (LoBAL) quasar in a post-starburst galaxy in data from the Dark Energy Survey (DES) and spectroscopy from the Australian Dark Energy Survey (OzDES). LoBAL quasars are a minority of all BALs, and rarer still is that this object also exhibits broad Fe II (an FeLoBAL) and Balmer absorption. This is the first BAL quasar that has signatures of recently truncated star formation, which we estimate ended about 40 Myr ago. The characteristic signatures of an FeLoBAL require high column densities, which could be explained by the emergence of a young quasar from an early, dust-enshrouded phase, or by clouds compressed by a blast wave. The age of the starburst component is comparable to estimates of the lifetime of quasars, so if we assume the quasar activity is related to the truncation of the star formation, this object is better explained by the blast wave scenario
VDES J2325â5229 a z = 2.7 gravitationally lensed quasar discovered using morphology-independent supervised machine learning
We present the discovery and preliminary characterization of a gravitationally lensed quasar with a source redshift zs = 2.74 and image separation of 2.9 arcsec lensed by a foreground zl = 0.40 elliptical galaxy. Since optical observations of gravitationally lensed quasars showthe lens system as a superposition of multiple point sources and a foreground lensing galaxy, we have developed a morphology-independent multi-wavelength approach to the photometric selection of lensed quasar candidates based on Gaussian Mixture Models (GMM) supervised machine learning. Using this technique and gi multicolour photometric observations from the Dark Energy Survey (DES), near-IR JK photometry from the VISTA Hemisphere Survey (VHS) and WISE mid-IR photometry, we have identified a candidate system with two catalogue components with iAB = 18.61 and iAB = 20.44 comprising an elliptical galaxy and two blue point sources. Spectroscopic follow-up with NTT and the use of an archival AAT spectrum show that the point sources can be identified as a lensed quasar with an emission line redshift of z = 2.739 ± 0.003 and a foreground early-type galaxy with z = 0.400 ± 0.002.We model the system as a single isothermal ellipsoid and find the Einstein radius ΞE ⌠1.47 arcsec, enclosed mass Menc ⌠4 Ă 1011 M and a time delay of âŒ52 d. The relatively wide separation, month scale time delay duration and high redshift make this an ideal system for constraining the expansion rate beyond a redshift of 1
J Clin Immunol
We report a longitudinal analysis of the immune response associated with a fatal case of COVID-19 in Europe. This patient exhibited a rapid evolution towards multiorgan failure. SARS-CoV-2 was detected in multiple nasopharyngeal, blood, and pleural samples, despite antiviral and immunomodulator treatment. Clinical evolution in the blood was marked by an increase (2â3-fold) in differentiated effector T cells expressing exhaustion (PD-1) and senescence (CD57) markers, an expansion of antibody-secreting cells, a 15-fold increase in γΎ T cell and proliferating NK-cell populations, and the total disappearance of monocytes, suggesting lung trafficking. In the serum, waves of a pro-inflammatory cytokine storm, Th1 and Th2 activation, and markers of T cell exhaustion, apoptosis, cell cytotoxicity, and endothelial activation were observed until the fatal outcome. This case underscores the need for well-designed studies to investigate complementary approaches to control viral replication, the source of the hyperinflammatory status, and immunomodulation to target the pathophysiological response. The investigation was conducted as part of an overall French clinical cohort assessing patients with COVID-19 and registered in clinicaltrials.gov under the following number: NCT04262921
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