864 research outputs found
Micropenis: an important early sign of congenital hypopituitarism
Micropenis is an important sign in neonates, since it may be
the only clue to the diagnosis of panhypopituitarism, a potentially lethal but eminently treatable condition
The Relationship Between Galaxies and Low Redshift Weak Lyman alpha Absorbers in the Directions of H1821+643 and PG1116+215
To study the nature of low z Lya absorbers in the spectra of QSOs, we have
obtained high signal-to-noise UV spectra of H 1821+643 (z = 0.297) and PG
1116+215 (z = 0.177) with the GHRS on the HST. The spectra have minimum S/N of
70-100 and 3 sigma limiting equivalent widths of 50-75 mA. We detect 26 Lya
lines with Wr > 50 mA toward H1821+643 and 13 toward PG1116+215, which implies
a density of 102+/-16 lines per unit redshift. The two-point correlation
function shows marginal evidence of clustering on ~500 km/s scales, but only if
the weakest lines are excluded. We have also used the WIYN Observatory to
measure galaxy redshifts in the ~1 degree fields centered on each QSO. We find
17 galaxy-absorber pairs within projected distances of 1 Mpc with velocity
separations of 350 km/s or less. Monte Carlo simulations show that if the Lya
lines are randomly distributed, the probability of observing this many close
pairs is 3.6e-5. We find that all galaxies with projected distances of 600 kpc
or less have associated Lya absorbers within 1000 km/s, and the majority of
these galaxies have absorbers within 350 km/s. We also find that the Lya
equivalent width is anticorrelated with the projected distance of the nearest
galaxy out to at least 600 kpc, but this should be interpreted cautiously
because there are potential selection biases. Statistical tests using the
entire sample also indicate that the absorbers are not randomly distributed. We
discuss the nature of the Lya absorbers in light of the new data.Comment: Accepted for publication in ApJ. 17 pages plus 11 tables and 17
figure
Mathematical modelling to restore circulating IGF-1 concentrations in children with Crohn's disease-induced growth failure: a pharmacokinetic study.
Children with Crohn's disease grow poorly, and inflammation depresses the response of insulin-like growth factor-1 (IGF-1) to growth hormone. Correcting the inflammation normalises growth velocity; however, removing inflammation cannot be achieved in all children. Our lack of understanding of IGF-1 kinetics has hampered its use, particularly as high IGF-1 concentrations over long periods may predispose to colon cancer. We hypothesised that mathematical modelling of IGF-1 would define dosing regimes that return IGF-1 concentrations into the normal range, without reaching values that risk cancer
Whole-exome sequencing gives additional benefits compared to candidate gene sequencing in the molecular diagnosis of children with growth hormone or IGF-1 insensitivity
Ipsen UK!(HLS).
Sandoz Pharmaceutical
Hot Halos around High Redshift Protogalaxies: Observations of O VI and N V Absorption in Damped Lyman Alpha systems
(ABRIDGED) We present a study of the highly ionized gas (plasma) associated
with damped Lyman-alpha (DLA) systems at z=2.1-3.1. We search for O VI
absorption and corresponding Si IV, C IV, and N V in a Very Large
Telescope/Ultraviolet-Visible Echelle Spectrograph (VLT/UVES) sample of 35 DLA
systems with data covering O VI at S/N>10. We report twelve DLAs (nine
intervening and three at <5000 km/s from the QSO redshift) with detections of O
VI absorption. There are no clear O VI non-detections, so the incidence of O VI
in DLAs is between 34% (12/35) and 100%. Analysis of the line widths together
with photoionization modelling suggests that two phases of DLA plasma exist: a
hot, collisionally ionized phase (seen in broad O VI components), and a warm,
photoionized phase (seen just in narrow C IV and Si IV components). We find
tentative evidence (98% confidence) for correlations between the DLA
metallicity (measured in the neutral gas) and high-ion column density, and
between the DLA metallicity and high-ion line width, as would be expected if
supernova-driven galactic outflows rather than accretion produced the high
ions. Using conservative ionization corrections, we find lower limits to the
total hydrogen column densities in the hot (O VI-bearing) and warm (C
IV-bearing) phases in the range log N(Hot H II) >19.5 to >21.1, and log N(Warm
H II) >19.4 to >20.9. On average, the hot and warm phases thus contain >40% and
>20% of the baryonic mass of the neutral phase in DLAs, respectively. If the
temperature in the O VI phase is ~10^6 K and so f(O VI)=O VI/O<<0.2 the plasma
can make a significant contribution to the metal budget at high redshift.Comment: 18 pages, 7 figures (3 in color), accepted to A&
Modeling the total and polarized emission in evolving galaxies: "spotty" magnetic structures
Future radio observations with the SKA and its precursors will be sensitive
to trace spiral galaxies and their magnetic field configurations up to redshift
. We suggest an evolutionary model for the magnetic configuration in
star-forming disk galaxies and simulate the magnetic field distribution, the
total and polarized synchrotron emission, and the Faraday rotation measures for
disk galaxies at z\la 3. Since details of dynamo action in young galaxies are
quite uncertain, we model the dynamo action heuristically relying only on
well-established ideas of the form and evolution of magnetic fields produced by
the mean-field dynamo in a thin disk. We assume a small-scale seed field which
is then amplified by the small-scale turbulent dynamo up to energy
equipartition with kinetic energy of turbulence. The large-scale galactic
dynamo starts from seed fields of 100 pc and an averaged regular field strength
of 0.02\,G, which then evolves to a "spotty" magnetic field configuration
in about 0.8\,Gyr with scales of about one kpc and an averaged regular field
strength of 0.6\,G. The evolution of these magnetic spots is simulated
under the influence of star formation, dynamo action, stretching by
differential rotation of the disk, and turbulent diffusion. The evolution of
the regular magnetic field in a disk of a spiral galaxy, as well as the
expected total intensity, linear polarization and Faraday rotation are
simulated in the rest frame of a galaxy at 5\,GHz and 150\,MHz and in the rest
frame of the observer at 150\,MHz. We present the corresponding maps for
several epochs after disk formation. (abridged)Comment: 13 pages, 6 figures, 2 tables, revised version is accepted for
publication in Astronomische Nachrichte
A pedagogic appraisal of the Priority Heuristic
We have explored how science and mathematics teachers made decisions when confronted with a dilemma in which a fictitious young woman, Deborah, may choose to have an operation that might address a painful spinal condition. We sought to explore the extent to which psychological heuristic models, in particular the Priority Heuristic, might successfully describe the decision-making process of these teachers and how an analysis of the role of personal and emotional factors in shaping the decision-making process might inform pedagogical design. A novel aspect of this study is that the setting in which the decision-making process is examined contrasts sharply with those used in psychological experiments. We found that to some extent, even in this contrasting setting, the Priority Heuristic could describe these teachers' decision-making. Further analysis of the transcripts yielded some insights into limitations on scope as well the richness and complexity in how personal factors were brought to bear. We see these limitations as design opportunities for educational intervention
Simulation of radiation driven wind from disc galaxies
We present 2-D hydrodynamic simulation of rotating galactic winds driven by
radiation. We study the structure and dynamics of the cool and/or warm
component( K) which is mixed with dust. We have taken into
account the total gravity of a galactic system that consists of a disc, a bulge
and a dark matter halo. We find that the combined effect of gravity and
radiation pressure from a realistic disc drives the gas away to a distance of
kpc in Myr for typical galactic parameters. The outflow
speed increases rapidly with the disc Eddington parameter ) for . We find that the rotation speed of
the outflowing gas is km s. The wind is confined in a
cone which mostly consist of low angular momentum gas lifted from the central
region.Comment: 10 pages, 11 figures, Accepted for publication in MNRA
Winter soil respiration in a humid temperate forest: The roles of moisture, temperature, and snowpack
Winter soil respiration at midlatitudes can comprise a substantial portion of annual ecosystem carbon loss. However, winter soil carbon dynamics in these areas, which are often characterized by shallow snow cover, are poorly understood due to infrequent sampling at the soil surface. Our objectives were to continuously measure winter CO2 flux from soils and the overlying snowpack while also monitoring drivers of winter soil respiration in a humid temperate forest. We show that the relative roles of soil temperature and moisture in driving winter CO2 flux differed within a single soil-to-snow profile. Surface soil temperatures had a strong, positive influence on CO2 flux from the snowpack, while soil moisture exerted a negative control on soil CO2 flux within the soil profile. Rapid fluctuations in snow depth throughout the winter likely created the dynamic soil temperature and moisture conditions that drove divergent patterns in soil respiration at different depths. Such dynamic conditions differ from many previous studies of winter soil microclimate and respiration, where soil temperature and moisture are relatively stable until snowmelt. The differential response of soil respiration to temperature and moisture across depths was also a unique finding as previous work has not simultaneously quantified CO2 flux from soils and the snowpack. The complex interplay we observed among snow depth, soil temperature, soil moisture, and CO2 flux suggests that winter soil respiration in areas with shallow seasonal snow cover is more variable than previously understood and may fluctuate considerably in the future given winter climate change
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