62 research outputs found
Incidence, aetiology and neurodisability associated with severe microcephaly: a national surveillance study
Objective
To determine the incidence, causes and neurodevelopmental impact of severe microcephaly (head circumference <â3SD) up to age 2 years.
Design
Binational active paediatric surveillance study undertaken in 2017â2018 to identify and characterise new diagnoses of severe microcephaly.
Setting
UK and Ireland.
Participants
Infants aged under 12 months at diagnosis.
Interventions
Observational study.
Main outcome measures
Incidence, aetiology and neurodevelopmental outcomes at age 2âyears.
Results
Fifty-nine infants met the case definition, of whom 30 (51%) were girls; 24 (41%) were born preterm (<37 weeksâ gestation); and 34 (58%) were of âwhiteâ ethnicity. Eight (14%) children died before 12 months of age. Incidence of severe microcephaly was 5.5 per 100 000 infants (95% CI 4.0 to 7.3). Higher relative risk (RR) was associated with preterm birth (RR 7.7, 95% CI 3.8 to 15.1) and British Asian ethnicity (RR 3.6, 95% CI 1.6 to 7.8). Microcephaly was mainly due to genetic causes (59%), brain ischaemia/hypoxia (10%) and congenital infection (8%), and 19% remained undetermined. Each child was referred on average to eight specialists, and 75% had abnormal brain imaging. By 2 years of age, 55 children experienced neurodevelopmental abnormalities, including feeding problems (68%), motor delay (66%), visual impairment (37%), hearing loss (24%) and epilepsy (41%).
Conclusions
Although severe microcephaly is uncommon, it is associated with high mortality, complex multimorbidity and neurodisability, thus representing a significant ongoing burden for families and healthcare services. Potentially preventable causes include preterm birth, hypoxic/ischaemic brain injury and congenital infections. Clinical guidelines are essential to standardise aetiological investigation and optimise multidisciplinary management
Dynamical Masses for Low-Mass Pre-Main Sequence Stars: A Preliminary Physical Orbit for HD 98800 B
We report on Keck Interferometer observations of the double-lined binary (B)
component of the quadruple pre-main sequence (PMS) system HD 98800. With these
interferometric observations combined with astrometric measurements made by the
Hubble Space Telescope Fine Guidance Sensors (FGS), and published radial
velocity observations we have estimated preliminary visual and physical orbits
of the HD 98800 B subsystem. Our orbit model calls for an inclination of 66.8
3.2 deg, and allows us to infer the masses and luminosities of the
individual components. In particular we find component masses of 0.699
0.064 and 0.582 0.051 M_{\sun} for the Ba (primary) and Bb (secondary)
components respectively.
Modeling of the component SEDs finds temperatures and luminosities in
agreement with previous studies, and coupled with the component mass estimates
allows for comparison with PMS models in the low-mass regime with few empirical
constraints. Solar abundance models seem to under-predict the inferred
component temperatures and luminosities, while assuming slightly sub-solar
abundances bring the models and observations into better agreement. The present
preliminary orbit does not yet place significant constraints on existing
pre-main sequence stellar models, but prospects for additional observations
improving the orbit model and component parameters are very good.Comment: 20 pages, 6 figures, ApJ in press; tables 2 and 3 to be included in
ApJ versio
Dynamical Masses for Pre-Main Sequence Stars: A Preliminary Physical Orbit for V773 Tau A
We report on interferometric and radial-velocity observations of the
double-lined 51-d period binary (A) component of the quadruple pre-main
sequence (PMS) system V773 Tau. With these observations we have estimated
preliminary visual and physical orbits of the V773 Tau A subsystem. Among other
parameters, our orbit model includes an inclination of 66.0 2.4 deg, and
allows us to infer the component dynamical masses and system distance. In
particular we find component masses of 1.54 0.14 and 1.332 0.097
M_{\sun} for the Aa (primary) and Ab (secondary) components respectively.
Our modeling of the subsystem component spectral energy distributions finds
temperatures and luminosities consistent with previous studies, and coupled
with the component mass estimates allows for comparison with PMS stellar models
in the intermediate-mass range. We compare V773 Tau A component properties with
several popular solar-composition models for intermediate-mass PMS stars. All
models predict masses consistent to within 2-sigma of the dynamically
determined values, though some models predict values that are more consistent
than others.Comment: ApJ in press; 25 pages, 6 figures; data tables available in journal
versio
Cosmological Obscuration by Galactic Dust: Effects of Dust Evolution
We explore the effects of dust in cosmologically distributed intervening
galaxies on the high redshift universe using a generalised model where dust
content evolves with cosmic time. The absorbing galaxies are modelled as
exponential disks which form coevally, maintain a constant space density and
evolve in dust content at a rate that is uniform throughout. We find that the
inclusion of moderate to moderately weak amounts of evolution consistent with
other studies can reduce the mean observed -band optical depth to redshifts
z \simgt 1 by at least 60% relative to non-evolving models. Our predictions
imply that intervening galactic dust is unlikely to bias the optical counts of
quasars at high redshifts and their evolution in space density derived
therefrom.Comment: 10 pages, 6 figures, Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Cadernos escolares: problemas aritméticos no ensino de matemåtica em um diårio escolar dos anos 1950
DisponĂvel em: http://histemat.com.br/index.php/HISTEMAT/article/view/140/96Este artigo aborda problemas aritmĂ©ticos encontrados em um caderno escolar do quarto ano do curso primĂĄrio, dos anos de 1950. O caderno utilizado como fonte de pesquisa pertenceu a um estudante do Grupo Escolar Ramiz GalvĂŁo, localizado em Rio Pardo, Rio Grande do Sul. Nessa Ă©poca estava em vigor, no Estado, o Decreto nÂș 8.020, de 1939, que estabelecia os programas mĂnimos do curso primĂĄrio, guiando os professores atĂ© o final dos anos 1950. O autor do caderno, Juvenal Rosa Nunes, concedeu uma entrevista que contribuiu para os resultados desta pesquisa. A partir de anĂĄlise do caderno, da entrevista e do Decreto, o artigo conclui que os problemas eram uma das principais atividades das aulas de MatemĂĄtica e que, por meio deles, a professora buscava retratar o cotidiano dos alunos e atingir os objetivos estabelecidos pelos programas. TambĂ©m sĂŁo identificadas semelhanças entre os temas e as redaçÔes dos enunciados dos problemas com enunciados encontrados em edição contemporĂąnea do livro âPrimeira AritmĂ©tica para meninosâ de Souza Lobo
In situ mantle cell lymphoma: clinical implications of an incidental finding with indolent clinical behavior
Background Cyclin D1-positive B cells are occasionally found in the mantle zones of reactive lymphoid follicles, a condition that has been called 'in situ mantle cell lymphoma'. The clinical significance of this lesion remains uncertain. Design and Methods The clinical and pathological characteristics, including SOX11 expression, of 23 cases initially diagnosed as in situ mantle cell lymphoma were studied. Results Seventeen of the 23 cases fulfilled the criteria for in situ mantle cell lymphoma. In most cases, the lesions were incidental findings in reactive lymph nodes. The t(11; 14) was detected in all eight cases examined. SOX11 was positive in seven of 16 cases (44%). Five cases were associated with other small B-cell lymphomas. In two cases, both SOX11-positive, the in situ mantle cell lymphoma lesions were discovered after the diagnosis of overt lymphoma; one 4 years earlier, and one 3 years later. Twelve of the remaining 15 patients had a follow-up of at least 1 year (median 2 years; range, 1-19.5), of whom 11 showed no evidence of progression, including seven who were not treated. Only one of 12 patients with an in situ mantle cell lymphoma lesion and no diagnosis of mantle cell lymphoma at the time developed an overt lymphoma, 4 years later; this case was also SOX11-positive. The six remaining cases were diagnosed as mantle cell lymphoma with a mantle zone pattern. Five were SOX11-positive and four of them were associated with lymphoma without a mantle zone pattern. Conclusions In situ mantle cell lymphoma lesions are usually an incidental finding with a very indolent behavior. These cases must be distinguished from mantle cell lymphoma with a mantle zone pattern and overt mantle cell lymphoma because they may not require therapeutic intervention
The Morphology of Galaxies in the Baryon Oscillation Spectroscopic Survey
We study the morphology of luminous and massive galaxies at 0.3<z<0.7
targeted in the Baryon Oscillation Spectroscopic Survey (BOSS) using publicly
available Hubble Space Telescope imaging from COSMOS. Our sample (240 objects)
provides a unique opportunity to check the visual morphology of these galaxies
which were targeted based solely on stellar population modelling. We find that
the majority (74+/-6%) possess an early-type morphology (elliptical or S0),
while the remainder have a late-type morphology. This is as expected from the
goals of the BOSS target selection which aimed to predominantly select slowly
evolving galaxies, for use as cosmological probes, while still obtaining a fair
fraction of actively star forming galaxies for galaxy evolution studies. We
show that a colour cut of (g-i)>2.35 selects a sub-sample of BOSS galaxies with
90% early-type morphology - more comparable to the earlier Luminous Red Galaxy
(LRG) samples of SDSS-I/II. The remaining 10% of galaxies above this cut have a
late-type morphology and may be analogous to the "passive spirals" found at
lower redshift. We find that 23+/-4% of the early-type galaxies are unresolved
multiple systems in the SDSS imaging. We estimate that at least 50% of these
are real associations (not projection effects) and may represent a significant
"dry merger" fraction. We study the SDSS pipeline sizes of BOSS galaxies which
we find to be systematically larger (by 40%) than those measured from HST
images, and provide a statistical correction for the difference. These details
of the BOSS galaxies will help users of the data fine-tune their selection
criteria, dependent on their science applications. For example, the main goal
of BOSS is to measure the cosmic distance scale and expansion rate of the
Universe to percent-level precision - a point where systematic effects due to
the details of target selection may become important.Comment: 18 pages, 11 figures; v2 as accepted by MNRA
CANDELS: The progenitors of compact quiescent galaxies at z~2
We combine high-resolution HST/WFC3 images with multi-wavelength photometry
to track the evolution of structure and activity of massive (log(M*) > 10)
galaxies at redshifts z = 1.4 - 3 in two fields of the Cosmic Assembly
Near-infrared Deep Extragalactic Legacy Survey (CANDELS). We detect compact,
star-forming galaxies (cSFGs) whose number densities, masses, sizes, and star
formation rates qualify them as likely progenitors of compact, quiescent,
massive galaxies (cQGs) at z = 1.5 - 3. At z > 2 most cSFGs have specific
star-formation rates (sSFR = 10^-9 yr^-1) half that of typical, massive SFGs at
the same epoch, and host X-ray luminous AGN 30 times (~30%) more frequently.
These properties suggest that cSFGs are formed by gas-rich processes (mergers
or disk-instabilities) that induce a compact starburst and feed an AGN, which,
in turn, quench the star formation on dynamical timescales (few 10^8 yr). The
cSFGs are continuously being formed at z = 2 - 3 and fade to cQGs by z = 1.5.
After this epoch, cSFGs are rare, thereby truncating the formation of new cQGs.
Meanwhile, down to z = 1, existing cQGs continue to enlarge to match local QGs
in size, while less-gas-rich mergers and other secular mechanisms shepherd
(larger) SFGs as later arrivals to the red sequence. In summary, we propose two
evolutionary scenarios of QG formation: an early (z > 2), fast-formation path
of rapidly-quenched cSFGs that evolve into cQGs that later enlarge within the
quiescent phase, and a slow, late-arrival (z < 2) path for SFGs to form QGs
without passing through a compact state.Comment: Submitted to the Astrophysical Journal Letters, 6 pages, 4 figure
The Evolution of the Baryons Associated with Galaxies Averaged over Cosmic Time and Space
We combine the recent determination of the evolution of the cosmic density of molecular gas (H2) using deep, volumetric surveys, with previous estimates of the cosmic density of stellar mass, star formation rate and atomic gas (H i), to constrain the evolution of baryons associated with galaxies averaged over cosmic time and space. The cosmic H i and H2 densities are roughly equal at z ~ 1.5. The H2 density then decreases by a factor to today's value, whereas the H i density stays approximately constant. The stellar mass density is increasing continuously with time and surpasses that of the total gas density (H i and H2) at redshift z ~ 1.5. The growth in stellar mass cannot be accounted for by the decrease in cosmic H2 density, necessitating significant accretion of additional gas onto galaxies. With the new H2 constraints, we postulate and put observational constraints on a two-step gas accretion process: (i) a net infall of ionized gas from the intergalactic/circumgalactic medium to refuel the extended H i reservoirs, and (ii) a net inflow of H i and subsequent conversion to H2 in the galaxy centers. Both the infall and inflow rate densities have decreased by almost an order of magnitude since z ~ 2. Assuming that the current trends continue, the cosmic molecular gas density will further decrease by about a factor of two over the next 5 Gyr, the stellar mass will increase by approximately 10%, and cosmic star formation activity will decline steadily toward zero, as the gas infall and accretion shut down
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems: Best Practices for Data Collection in Cycle 2 and Beyond
We present a set of recommended best practices for JWST data collection for
members of the community focussed on the direct imaging and spectroscopy of
exoplanetary systems. These findings and recommendations are based on the early
analysis of the JWST Early Release Science Program 1386, "High-Contrast Imaging
of Exoplanets and Exoplanetary Systems with JWST." Our goal is for this
information to be useful for observers in preparation of JWST proposals for
Cycle 2 and beyond. In addition to compiling a set of best practices from our
ERS program, in a few cases we also draw on the expertise gained within the
instrument commissioning programs, as well as include a handful of data
processing best practices. We anticipate that this document will be regularly
updated and resubmitted to arXiv.org to ensure that we have distributed our
knowledge of best-practices for data collection as widely and efficiently as
possible.Comment: Not yet submitted for publication. Intended only to be a community
resource for JWST Cycle 2 proposal
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