10,264 research outputs found
Ratio of Isoscalar to Isovector Core Polarization for Magnetic Moments
In calculations of isoscalar magnetic moments of odd-odd N=Z nuclei it was
found that for medium to heavy mass nuclei large scale shell model calculations
yielded results which were very close to much simpler single j shell ones. To
understand this we compare isoscalar and isovector configuration mixing in
first order perturbation theory using a spin dependant delata interaction.The
isoscalar corrections are much smalle
Unique case of inverted papilloma of septum with nasopharyngeal carcinoma:Is it a metachronous tumour?
Inverted papilloma is a rare and benign tumour. It affects the nasal cavity and paranasal sinuses, has a high rate of recurrence and is associated with malignant transformation. Only few cases of a poorly differentiated carcinoma arising from inverted papilloma have been reported, none of which in the nasopharynx. We report a case of a 37-year-old female, who presented originally in 2012 with inverted papilloma of the nasal septum which was surgically resected. Nasopharyngeal biopsy from 2014 was reported as carcinoma in situ and treated with local endoscopic resection. Three years later she presented with a solitary lesion of the right Eustachian tube opening, confirmed as invasive poorly differentiated carcinoma. Imaging revealed T4 N2b M0 malignancy with skull base and prevertebral space invasion, likely extension into right temporal lobe and malignant adenopathy. Although rare, malignant transformation of inverted papilloma in unusual places should be considered during workup and monitoring of patients
DOES MOTHER KNOW BEST?: A COMPARISON OF BIOLOGICAL AND SOCIAL FATHERS AFTER A NONMARITAL BIRTH
High rates of nonmarital childbearing combined with high rates of instability and repartnering in nonmarital relationships portend that a large proportion of children born to unmarried mothers can expect to spend time with a ‘social father.’ This paper uses data from the Fragile Families and Child Wellbeing Study to examine the prevalence and characteristics of social fathers during the first three years following a nonmarital birth. The results indicate that 22% of unmarried mothers have formed new partnerships by the time their child is age three, and 12% are living with their new partners. The results also indicate that re-partnering represents a gain for most mothers and children in terms of fathers’ human capital and pro-social behavior. Our findings are consistent with the idea that unmarried mothers continue to search for ‘good fathers’ after their children are born and that many of these women are successful in their search.
Crack Front Waves and the dynamics of a rapidly moving crack
Crack front waves are localized waves that propagate along the leading edge
of a crack. They are generated by the interaction of a crack with a localized
material inhomogeneity. We show that front waves are nonlinear entities that
transport energy, generate surface structure and lead to localized velocity
fluctuations. Their existence locally imparts inertia, which is not
incorporated in current theories of fracture, to initially "massless" cracks.
This, coupled to crack instabilities, yields both inhomogeneity and scaling
behavior within fracture surface structure.Comment: Embedded Latex file including 4 figure
Complete genome sequence of Torque teno indri virus 1, a novel anellovirus in blood from a free-living lemur
ABSTRACT
We identified
Torque teno indri virus 1
(TTIV1), the first anellovirus in a free-living lemur (
Indri indri
). The complete circular 2,572-nucleotide (nt) TTIV1 genome is distantly related to torque teno sus virus. Phylogenetic and sequence analyses support TTIV1 as a putative member of a new genus within the
Anelloviridae
family.
</jats:p
An engineered cardiac reporter cell line identifies human embryonic stem cell-derived myocardial precursors.
Unlike some organs, the heart is unable to repair itself after injury. Human embryonic stem cells (hESCs) grow and divide indefinitely while maintaining the potential to develop into many tissues of the body. As such, they provide an unprecedented opportunity to treat human diseases characterized by tissue loss. We have identified early myocardial precursors derived from hESCs (hMPs) using an α-myosin heavy chain (αMHC)-GFP reporter line. We have demonstrated by immunocytochemistry and quantitative real-time PCR (qPCR) that reporter activation is restricted to hESC-derived cardiomyocytes (CMs) differentiated in vitro, and that hMPs give rise exclusively to muscle in an in vivo teratoma formation assay. We also demonstrate that the reporter does not interfere with hESC genomic stability. Importantly, we show that hMPs give rise to atrial, ventricular and specialized conduction CM subtypes by qPCR and microelectrode array analysis. Expression profiling of hMPs over the course of differentiation implicate Wnt and transforming growth factor-β signaling pathways in CM development. The identification of hMPs using this αMHC-GFP reporter line will provide important insight into the pathways regulating human myocardial development, and may provide a novel therapeutic reagent for the treatment of cardiac disease
Gravitational Radiation Instability in Hot Young Neutron Stars
We show that gravitational radiation drives an instability in hot young
rapidly rotating neutron stars. This instability occurs primarily in the l=2
r-mode and will carry away most of the angular momentum of a rapidly rotating
star by gravitational radiation. On the timescale needed to cool a young
neutron star to about T=10^9 K (about one year) this instability can reduce the
rotation rate of a rapidly rotating star to about 0.076\Omega_K, where \Omega_K
is the Keplerian angular velocity where mass shedding occurs. In older colder
neutron stars this instability is suppressed by viscous effects, allowing older
stars to be spun up by accretion to larger angular velocities.Comment: 4 Pages, 2 Figure
Agrin isoforms and their role in synaptogenesis
Agrin is thought to mediate the motor neuron-induced aggregation of synaptic proteins on the surface of muscle fibers at neuromuscular junctions. Recent experiments provide direct evidence in support of this hypothesis, reveal the nature of agrin immunoreactivity at sites other than neuromuscular junctions, and have resulted in findings that are consistent with the possibility that agrin plays a role in synaptogenesis throughout the nervous system
Accurately predicting the escape fraction of ionizing photons using restframe ultraviolet absorption lines
The fraction of ionizing photons that escape high-redshift galaxies
sensitively determines whether galaxies reionized the early universe. However,
this escape fraction cannot be measured from high-redshift galaxies because the
opacity of the intergalactic medium is large at high redshifts. Without methods
to indirectly measure the escape fraction of high-redshift galaxies, it is
unlikely that we will know what reionized the universe. Here, we analyze the
far-ultraviolet (UV) H I (Lyman series) and low-ionization metal absorption
lines of nine low-redshift, confirmed Lyman continuum emitting galaxies. We use
the H I covering fractions, column densities, and dust attenuations measured in
a companion paper to predict the escape fraction of ionizing photons. We find
good agreement between the predicted and observed Lyman continuum escape
fractions (within ) using both the H I and ISM absorption lines. The
ionizing photons escape through holes in the H I, but we show that dust
attenuation reduces the fraction of photons that escape galaxies. This means
that the average high-redshift galaxy likely emits more ionizing photons than
low-redshift galaxies. Two other indirect methods accurately predict the escape
fractions: the Ly escape fraction and the optical [O III]/[O II] flux
ratio. We use these indirect methods to predict the escape fraction of a sample
of 21 galaxies with rest-frame UV spectra but without Lyman continuum
observations. Many of these galaxies have low escape fractions (\%), but 11 have escape fractions \%. The methods presented here will
measure the escape fractions of high-redshift galaxies, enabling future
telescopes to determine whether star-forming galaxies reionized the early
universe.Comment: Accepted for publication in A&A. 12 pages, 5 figure
Flexible fluoropolymer filled protective coatings
Metal oxide films such as SiO2 are known to provide an effective barrier to the transport of moisture as well as gaseous species through polymeric films. Such thin film coatings have a tendency to crack upon flexure of the polymeric substrate. Sputter co-deposition of SiO2 with 4 to 15 percent fluoropolymers was demonstrated to produce thin films with glass-like barrier properties that have significant increases in strain to failure over pure glass films which improves their tolerance to flexure on polymeric substrates. Deposition techniques capable of producing these films on polymeric substrates are suitable for durable food packaging and oxidation/corrosion protection applications
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