645 research outputs found
Supporting Practicing School Counselor’s Skill Development: A Hip Hop and Spoken Word Professional Development Intervention
Given the paucity of professional development (PD) opportunities, gaps in cultural competence, and deterioration of direct counseling service opportunities for many school counselors, it is reasonable to conjecture that there is an inadvertent abandonment of skill development and related student outcomes. This mixed-methods study sought to evaluate the effectiveness of an innovative PD series for school counselors, exploring participants\u27 self-efficacy in counseling skill use and cross-cultural competence. The researchers administered a multi-session PD to school counselors in an Urban, Northeast School District in the US. Data from pre- and post-training surveys, vignettes, and post-training focus groups indicated a significant decrease in participants’ self-efficacy pre- to post-training. Further, results suggest participants learned innovative practice, practiced humanistic counseling skills, and understood new potential for student growth
Protostellar collapse: A comparison between SPH and AMR calculations
The development of parallel supercomputers allows today the detailed study of
the collapse and the fragmentation of prestellar cores with increasingly
accurate numerical simulations. Thanks to the advances in sub-millimeter
observations, a wide range of observed initial conditions enable us to study
the different modes of low-mass star formation. The challenge for the
simulations is to reproduce the observational results. Two main numerical
methods, namely AMR and SPH, are widely used to simulate the collapse and the
fragmentation of prestellar cores. We compare thoroughly these two methods
within their standard framework. We use the AMR code RAMSES and the SPH code
DRAGON. Our physical model is as simple as possible and consists of an
isothermal sphere rotating around the z-axis. We first study the conservation
of angular momentum as a function of the resolution. Then, we explore a wide
range of simulation parameters to study the fragmentation of prestellar cores.
There seems to be a convergence between the two methods, provided resolution in
each case is sufficient. Resolution criteria adapted to our physical cases, in
terms of resolution per Jeans mass, for an accurate description of the
formation of protostellar cores are deduced from the present study. This
convergence is encouraging for future work in simulations of low-mass star
formation, providing the aforementioned criteria are fulfilled.
Higher resolution figures can be downloaded at
http://www-dapnia.cea.fr/Projets/COAST/paper_amrvssph.pdfComment: 16 pages, 16 figures, accepted for publication in A&
The supernova remnant CTB 37B and its associated magnetar CXOU J171405.7-381031: evidence for a magnetar-driven remnant
We discuss in this Letter the association of the candidate magnetar CXOU
J171405.7-381031 with the supernova remnant CTB 37B. The recent detection of
the period derivative of the object allowed an estimation of a young
characteristic age of only . This value is too small to be
compatible even with the minimum radius of the remnant , the value
corresponding to the {\it lower} limit of the estimated distance of , unless the true distance happens to be even smaller than the lower
limit. We argue that a consistent scenario for the remnant origin, in which the
latter is powered by the energy injected by a young magnetar, is indeed more
accurate to explain the young age, and points out to its non-standard (i.e.
magnetar-driven) nature.Comment: 6 pp., 1 figure, to appear in RAA Letter
Developing trauma-informed teacher education in England
Trauma-informed practice in education is an area of growing interest in England and internationally. Embracing trauma-informed practice in schools requires trauma and related content to be included in teacher education. Over a period of eight years, a short course was developed and incorporated into the teacher preparation programmes at a large university in England. Through methods of teacher educator self-study and autoethnography, we examine the process of the course’s development and identify mechanisms, enablers and barriers to change in the current policy context of teacher education in England. Important factors that supported change were the gradual development, external collaboration, positive outcomes as a warrant and source of motivation, the development of champions and enthusiasts for trauma-informed practice, and departmental leadership support. Barriers to the development were the constraints of prescribed content on initial teacher education courses, prevailing practices in some schools and settings, challenges in adapting material suitably for all education phases, and some beginning teachers’ responses to personally relevant course content. The successful introduction of the short course demonstrates that inclusion of trauma-informed content in initial teacher education is possible even in an unfavourable policy environment
The evolution of mass loaded supernova remnants: II. Temperature dependent mass injection rates
We investigate the evolution of spherically symmetric supernova remnants in which mass loading takes place due to conductively driven evaporation of embedded clouds. Numerical simulations reveal significant differences between the evolution of conductively mass loaded and the ablatively mass loaded remnants studied in Paper I. A main difference is the way in which conductive mass loading is extinguished at fairly early times, once the interior temperature of the remnant falls below ~ 107 K. Thus, at late times remnants that ablatively mass load are dominated by loaded mass and thermal energy, while those that conductively mass load are dominated by swept-up mass and kinetic energy. Simple approximations to the remnant evolution, complementary to those in Paper I, are given
The contribution of supernova remnants to the galactic cosmic ray spectrum
The supernova paradigm for the origin of galactic cosmic rays has been deeply
affected by the development of the non-linear theory of particle acceleration
at shock waves. Here we discuss the implications of applying such theory to the
calculation of the spectrum of cosmic rays at Earth as accelerated in supernova
remnants and propagating in the Galaxy. The spectrum is calculated taking into
account the dynamical reaction of the accelerated particles on the shock, the
generation of magnetic turbulence which enhances the scattering near the shock,
and the dynamical reaction of the amplified field on the plasma. Most
important, the spectrum of cosmic rays at Earth is calculated taking into
account the flux of particles escaping from upstream during the Sedov-Taylor
phase and the adiabatically decompressed particles confined in the expanding
shell and escaping at later times. We show how the spectrum obtained in this
way is well described by a power law in momentum with spectral index close to
-4, despite the concave shape of the instantaneous spectra of accelerated
particles. On the other hand we also show how the shape of the spectrum is
sensible to details of the acceleration process and environment which are and
will probably remain very poorly known.Comment: 19 pages, 8 figures, published version (references updated
An adjustable law of motion for relativistic spherical shells
A classical and a relativistic law of motion for an advancing shell are
deduced applying the thin layer approximation. A new parameter connected with
the quantity of absorbed matter in the expansion is introduced; this allows of
matching theory and observation.Comment: 15 pages, 10 figures and article in press; Central European Journal
of Physics 201
Gas Accretion is Dominated by Warm Ionized Gas in Milky Way-Mass Galaxies at z ~ 0
We perform high-resolution hydrodynamic simulations of a Milky Way-mass
galaxy in a fully cosmological setting using the adaptive mesh refinement code,
Enzo, and study the kinematics of gas in the simulated galactic halo. We find
that the gas inflow occurs mostly along filamentary structures in the halo. The
warm-hot (10^5 K 10^6 K) ionized gases are found to
dominate the overall mass accretion in the system (with dM/dt = 3-5 M_solar/yr)
over a large range of distances, extending from the virial radius to the
vicinity of the disk. Most of the inflowing gas (by mass) does not cool, and
the small fraction that manages to cool does so primarily close to the galaxy
(R <~ 20 kpc), perhaps comprising the neutral gas that may be detectable as,
e.g., high-velocity clouds. The neutral clouds are embedded within larger,
accreting filamentary flows, and represent only a small fraction of the total
mass inflow rate. The inflowing gas has relatively low metallicity (Z/Z_solar <
0.2). The outer layers of the filamentary inflows are heated due to compression
as they approach the disk. In addition to the inflow, we find high-velocity,
metal-enriched outflows of hot gas driven by supernova feedback. Our results
are consistent with observations of halo gas at low z.Comment: 10 pages including 5 figures, submitted to Ap
川の中の昆虫たち
There is provided a novel derivative of 2-acetoxybenzoic acid, i.e., 1-O-(2\u27-acetoxy)benzoyl-α-D-2-deoxyglucopyranose, which is suitable for the attainment of high 2-acetoxybenzoic acid blood levels without irritation of the gastrointestinal lining
Non-linear diffusive acceleration of heavy nuclei in supernova remnant shocks
We describe a semi-analytical approach to non-linear diffusive shock
acceleration in the case in which nuclei other than protons are also
accelerated. The structure of the shock is determined by the complex interplay
of all nuclei, and in turn this shock structure determines the spectra of all
components. The magnetic field amplification upstream is described as due to
streaming instability of all nuclear species. The amplified magnetic field is
then taken into account for its dynamical feedback on the shock structure as
well as in terms of the induced modification of the velocity of the scattering
centers that enters the particle transport equation. The spectra of accelerated
particles are steep enough to be compared with observed cosmic ray spectra only
if the magnetic field is sufficiently amplified and the scattering centers have
high speed in the frame of the background plasma. We discuss the implications
of this generalized approach on the structure of the knee in the all-particle
cosmic ray spectrum, which we interpret as due to an increasingly heavier
chemical composition above eV. The effects of a non trivial chemical
composition at the sources on the gamma ray emission from a supernova remnant
when gamma rays are of hadronic origin are also discussed.Comment: 23 pages, 5 figures, minor changes to reflect the published versio
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