6,767 research outputs found
Stepfather Involvement and Stepfather-Child Relationship Quality: Race and Parental Marital Status as Moderators
Stepparent-child relationship quality is linked to stepfamily stability and children’s well-being. Yet, the literature offers an incomplete understanding of factors that promote high quality stepparent-child relationships, especially among socio-demographically diverse stepfamilies. In this study we explore the association between stepfather involvement and stepfather-child relationship quality among a racially diverse and predominately low-income sample of stepfamilies with pre-adolescent children. Using a subsample of 467 mother-stepfather families from year 9 of the Fragile Families and Child Wellbeing Study, results indicate that stepfather involvement is positively associated with stepfather-child relationship quality. This association is statistically indistinguishable across racial groups, although the association is stronger among children in cohabiting stepfamilies compared to children in married stepfamilies
EChO Payload electronics architecture and SW design
EChO is a three-modules (VNIR, SWIR, MWIR), highly integrated spectrometer,
covering the wavelength range from 0.55 m, to 11.0 m. The baseline
design includes the goal wavelength extension to 0.4 m while an optional
LWIR module extends the range to the goal wavelength of 16.0 m.
An Instrument Control Unit (ICU) is foreseen as the main electronic subsystem
interfacing the spacecraft and collecting data from all the payload
spectrometers modules. ICU is in charge of two main tasks: the overall payload
control (Instrument Control Function) and the housekeepings and scientific data
digital processing (Data Processing Function), including the lossless
compression prior to store the science data to the Solid State Mass Memory of
the Spacecraft. These two main tasks are accomplished thanks to the Payload On
Board Software (P-OBSW) running on the ICU CPUs.Comment: Experimental Astronomy - EChO Special Issue 201
Glitches in Southern Pulsars
Timing observations of 40 mostly young pulsars using the ATNF Parkes radio
telescope between 1990 January and 1998 December are reported. In total, 20
previously unreported glitches and ten other glitches were detected in 11
pulsars. These included 12 glitches in PSR J13416220, corresponding to a
glitch rate of 1.5 glitches per year. We also detected the largest known
glitch, in PSR J16145047, with
where is the pulse frequency. Glitch parameters were determined
both by extrapolating timing solutions to inter-glitch intervals and by
phase-coherent timing fits across the glitch(es). Analysis of glitch
parameters, both from this work and from previously published results, shows
that most glitches have a fractional amplitude of between
and . There is no consistent relationship between glitch
amplitude and the time since the previous glitch or the time to the following
glitch, either for the ensemble or for individual pulsars. As previously
recognised, the largest glitch activity is seen in pulsars with ages of order
10 years, but for about 30 per cent of such pulsars, no glitches were
detected in the 8-year data span. There is some evidence for a new type of
timing irregularity in which there is a significant increase in pulse frequency
over a few days, accompanied by a decrease in the magnitude of the slowdown
rate. Fits of an exponential recovery to post-glitch data show that for most
older pulsars, only a small fraction of the glitch decays. In some younger
pulsars, a large fraction of the glitch decays, but in others, there is very
little decay.Comment: 19 pages, 20 figures. Accepted for publication in MNRA
Langevin dynamics of heavy flavors in relativistic heavy-ion collisions
We study the stochastic dynamics of c and b quarks, produced in hard initial
processes, in the hot medium created after the collision of two relativistic
heavy ions. This is done through the numerical solution of the relativistic
Langevin equation. The latter requires the knowledge of the friction and
diffusion coefficients, whose microscopic evaluation is performed treating
separately the contribution of soft and hard collisions. The evolution of the
background medium is described by ideal/viscous hydrodynamics. Below the
critical temperature the heavy quarks are converted into hadrons, whose
semileptonic decays provide single-electron spectra to be compared with the
current experimental data measured at RHIC. We focus on the nuclear
modification factor R_AA and on the elliptic-flow coefficient v_2, getting, for
sufficiently large p_T, a reasonable agreement.Comment: Talk given at the workshop "Jets in Proton-Proton and Heavy-Ion
Collisions", Prague, 12th-14th August 201
The distribution of oxygen at the Ni81Fe19/Ta interface
The knowledge of how oxygen atoms are distributed at a magnetic-metal /
oxide, or magnetic-metal / non-magnetic-metal interface, can be an useful tool
to optimize device production. Multilayered Ni81Fe19 / Ta samples consisting of
15 bilayers of 2.5 nm each, grown onto glass substrates by magnetron sputtering
from Ni81Fe19 and Ta targets, have been investigated. X-ray absorption near
edge structure, extended X-Ray absorption fine structure, small angle X-ray
diffraction, and simulations, were used to characterize the samples. Oxygen
atoms incorporated onto Ni81Fe19 films during O2 exposition are mainly bonded
to Fe atoms. This partial oxidation of the Ni81Fe19 surface works as a barrier
to arriving Ta atoms, preventing intermixing at the Ni81Fe19 / Ta interface.
The reduction of the Ni81Fe19 surface by the formation of TaO x is observed.Comment: 14 pages, 9 figures, accepted for publication in Advances in
Materials Science and Engineerin
Toxicity and morbility after isolated lower limb perfusion in 242 chemo-hyperthermal treatments for cutaneous melanoma: The experience of the Tuscan Reference Centre
<p>Abstract</p> <p>Background</p> <p>The aim of this retrospective study was to assess the results concerning the regional and systemic toxicity and complications in 242 chemo-hyperthermal treatments (HILPs) for lower limb melanoma.</p> <p>Patients and methods</p> <p>60 HILPs (G-A) were performed with mild HT plus L-PAM (10 mg/lt) ± D-actimomycin; 74 HILPs (G-B) with true HT (40–41.8°C) plus L-PAM (10 mg/lt) ± D-act; 108 HILPs (G-C) with true HT plus L-PAM (10 mg/lt) ± D-act plus L-PAM (5 mg/lt) additional bolus.</p> <p>Results</p> <p>Limb toxicity was very low in G-A and in G-B; increasing toxicity (grade III = 37%) in G-C; no grade IV statistical difference was registered in all three groups, with percentage values among 1.6% and 2.7%. Systemic toxicity showed itself only in the haemopoietic parameters. No differences were registered in G-B vs G-A group. In G-C vs G-B a significative increase of systemic toxicity was seen in grade 3 (p < 0.05). Postoperative complications were acceptable. Local and systemic side-effects were transient; no permanent neurological limb deficit was registered. The postoperative mortality was recorded in 3/182 HILPs (1.6%) of the G-B and G-C groups.</p> <p>Conclusion</p> <p>These data suggested that the technical implementations reduced the occurrence and the severity of the side effects and complications. The essential requirement for HILP is the quality assurance of the procedures. Although higher regional and systemic toxicity were observed in the G-C group caused by L-PAM additional bolus, the safeness of the procedures under the true hyperthermal regimen and the time increase of the high L-PAM concentration have assured the treatment reliability along with the increased clinical efficacy expectations of the treatments.</p
Detection of the Vortex Dynamic Regimes in MgB2 by Third Harmonic AC Susceptibility Measurements
In a type-II superconductor the generation of higher harmonics in the
magnetic response to an alternating magnetic field is a consequence of the
non-linearity in the I-V relationship. The shape of the current-voltage (I-V)
curve is determined by the current dependence of the thermal activation energy
U(J) and is thus related to the dynamical regimes governing the vortex motion.
In order to investigate the vortex dynamics in MgB2 bulk superconductors we
have studied the fundamental (chi1) and third (chi3) harmonics of the ac
magnetic susceptibility. Measurements have been performed as a function of the
temperature and the dc magnetic field, up to 9 T, for various frequencies and
amplitudes of the ac field. We show that the analysis of the behaviour in
frequency of chi3(T) and chi3(B) curves can provide clear information about the
non-linearity in different regions of the I-V characteristic. By comparing the
experimental curves with numerical simulations of the non-linear diffusion
equation for the magnetic field we are able to resolve the crossover between a
dissipative regime governed by flux creep and one dominated by flux flow
phenomena.Comment: to be published in "Horizons in Superconductivity Research" (Nova
Science Publishers, Inc., NY, 2003
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