5,723 research outputs found
First national survey of practitioners with early yearsâ professional status
The first national survey of practitioners who have achieved Early Years Professional Status (EYPS)
set out to ascertain:
⢠more detailed demographic information about their backgrounds and experience
⢠their views on their ability to carry out their role since gaining EYPS
⢠information about career trajectories including their intentions to change setting, role or career
⢠an overview of their professional development activities and plans
⢠an assessment of the impact of obtaining EYPS on professional identity
⢠their views on the difficulty of achieving change in their settings.
This survey is part of a three year longitudinal study investigating the role and impact of early years professionals (EYPs) in their working environments (settings) and also investigating practitionersâ personal career development and aspirations. There are two main parts to the study:
⢠a survey of all EYPs, asking about their career development needs and aspirations
⢠case studies in 30 settings across the country, looking at how EYPs have an impact on the quality of education and care available to children.
The survey, with slight modifications, will be repeated in year three of the study. The intention was to make the survey accessible to all who have achieved EYPS, with the aim of generating responses from approximately 10-15 per cent of respondents. The survey went live between January and February 2010 and by the close of the survey some 1,045 completed questionnaires had been generated, representing nearly 30 per cent of the total number of practitioners with EYPS. This sample was broadly representative of the total population of practitioners with EYPS based on gender, ethnicity, geographical distribution and the pathway they had followed to achieve EYPS
Gas dynamics in the inner few AU around the Herbig B[e] star MWC297: Indications of a disk wind from kinematic modeling and velocity-resolved interferometric imaging
We present near-infrared AMBER (R = 12, 000) and CRIRES (R = 100, 000)
observations of the Herbig B[e] star MWC297 in the hydrogen Br-gamma-line.
Using the VLTI unit telescopes, we obtained a uv-coverage suitable for aperture
synthesis imaging. We interpret our velocity-resolved images as well as the
derived two-dimensional photocenter displacement vectors, and fit kinematic
models to our visibility and phase data in order to constrain the gas velocity
field on sub-AU scales. The measured continuum visibilities constrain the
orientation of the near-infrared-emitting dust disk, where we determine that
the disk major axis is oriented along a position angle of 99.6 +/- 4.8 degrees.
The near-infrared continuum emission is 3.6 times more compact than the
expected dust-sublimation radius, possibly indicating the presence of highly
refractory dust grains or optically thick gas emission in the inner disk. Our
velocity-resolved channel maps and moment maps reveal the motion of the
Br-gamma-emitting gas in six velocity channels, marking the first time that
kinematic effects in the sub-AU inner regions of a protoplanetary disk could be
directly imaged. We find a rotation-dominated velocity field, where the blue-
and red-shifted emissions are displaced along a position angle of 24 +/- 3
degrees and the approaching part of the disk is offset west of the star. The
visibility drop in the line as well as the strong non-zero phase signals can be
modeled reasonably well assuming a Keplerian velocity field, although this
model is not able to explain the 3 sigma difference that we measure between the
position angle of the line photocenters and the position angle of the dust
disk. We find that the fit can be improved by adding an outflowing component to
the velocity field, as inspired by a magneto-centrifugal disk-wind scenario.Comment: 15 pages, 13 Figure
A re-evaluation of the central velocity-dispersion profile in NGC 6388
Recently, two independent groups found very different results when measuring
the central velocity dispersion of the galactic globular cluster NGC 6388 with
different methods. While L\"utzgendorf et al. (2011) found a rising profile and
a high central velocity dispersion (23.3 km/s), measurements obtained by
Lanzoni et al. (2013) showed a value 40% lower. The value of the central
velocity dispersion has a serious impact on the mass and possible presence of
an intermediate-mass black hole at the center of NGC 6388. We use a photometric
catalog of NGC 6388 to create a simulated SINFONI and ARGUS dataset. The
construction of the IFU data cube is done with different observing conditions
reproducing the conditions reported for the original observations as closely as
possible. In addition, we produce an N-body realization of a 10^6 M_SUN stellar
cluster with the same photometric properties as NGC 6388 to account for
unresolved stars. We find that the individual radial velocities, i.e. the
measurements from the simulated SINFONI data, are systematically biased towards
lower velocity dispersions. The reason is that due to the wings in the point
spread function the velocities get biased towards the mean cluster velocity.
This study shows that even with AO supported observations, individual radial
velocities in crowded fields are likely to be biased. The ARGUS observations do
not show this kind of bias but were found to have larger uncertainties than
previously obtained. We find a bias towards higher velocity dispersions in the
ARGUS pointing when fixing the extreme velocities of the three brightest stars
but find those variations are within the determined uncertainties. We rerun
Jeans models and fit the kinematic profile with the new uncertainties. This
yields a BH mass of M_BH = (2.8 +- 0.4) x 10^4 M_SUN and M/L ratio M/L = (1.6
+- 0.1) M_SUN/L_SUN, consistent with our previous results.Comment: 8 pages, 8 figure, accepted for publication in A&
Spectral Control via Multi-Species Effects in PW-Class Laser-Ion Acceleration
Laser-ion acceleration with ultra-short pulse, PW-class lasers is dominated
by non-thermal, intra-pulse plasma dynamics. The presence of multiple ion
species or multiple charge states in targets leads to characteristic
modulations and even mono-energetic features, depending on the choice of target
material. As spectral signatures of generated ion beams are frequently used to
characterize underlying acceleration mechanisms, thermal, multi-fluid
descriptions require a revision for predictive capabilities and control in
next-generation particle beam sources. We present an analytical model with
explicit inter-species interactions, supported by extensive ab initio
simulations. This enables us to derive important ensemble properties from the
spectral distribution resulting from those multi-species effects for arbitrary
mixtures. We further propose a potential experimental implementation with a
novel cryogenic target, delivering jets with variable mixtures of hydrogen and
deuterium. Free from contaminants and without strong influence of hardly
controllable processes such as ionization dynamics, this would allow a
systematic realization of our predictions for the multi-species effect.Comment: 4 pages plus appendix, 11 figures, paper submitted to a journal of
the American Physical Societ
High-velocity stars in the cores of globular clusters: The illustrative case of NGC 2808
We report the detection of five high-velocity stars in the core of the
globular cluster NGC 2808. The stars lie on the the red giant branch and show
total velocities between 40 and 45 km/s. For a core velocity dispersion sigma_c
= 13.4 km/s, this corresponds to up to 3.4 sigma_c. These velocities are close
to the estimated escape velocity (~ 50 km/s) and suggest an ejection from the
core. Two of these stars have been confirmed in our recent integral field
spectroscopy data and we will discuss them in more detail here. These two red
giants are located at a projected distance of ~ 0.3 pc from the center.
According to their positions on the color magnitude diagram, both stars are
cluster members. We investigate several possible origins for the high
velocities of the stars and conceivable ejection mechanisms. Since the
velocities are close to the escape velocity, it is not obvious whether the
stars are bound or unbound to the cluster. We therefore consider both cases in
our analysis. We perform numerical simulations of three-body dynamical
encounters between binaries and single stars and compare the resulting velocity
distributions of escapers with the velocities of our stars. We compare the
predictions for a single dynamical encounter with a compact object with those
of a sequence of two-body encounters due to relaxation. If the stars are
unbound, the encounter must have taken place recently, when the stars were
already in the giant phase. After including binary fractions and black-hole
retention fractions, projection effects, and detection probabilities from
Monte-Carlo simulations, we estimate the expected numbers of detections for all
the different scenarios. Based on these numbers, we conclude that the most
likely scenario is that the stars are bound and were accelerated by a single
encounter between a binary of main-sequence stars and a ~ 10 M_sun black hole.Comment: 13 pages, 12 figures, Accepted for publication in A&
Improved Formalism for Precision Higgs Coupling Fits
Future e+e- colliders give the promise of model-independent determinations of
the couplings of the Higgs boson. In this paper, we present an improved
formalism for extracting Higgs boson couplings from e+e- data, based on the
Effective Field Theory description of corrections to the Standard Model. We
apply this formalism to give projections of Higgs coupling accuracies for
stages of the International Linear Collider and for other proposed e+e-
colliders.Comment: 34 pages, 4 figures; v4: clarifications and new references added; v5,
additional references adde
The global warming hiatus: Slowdown or redistribution?
Global mean surface temperatures (GMST) exhibited a smaller rate of warming during 1998-2013, compared to the warming in the latter half of the 20th Century. Although, not a "true" hiatus in the strict definition of the word, this has been termed the "global warming hiatus" by IPCC (2013). There have been other periods that have also been defined as the "hiatus" depending on the analysis. There are a number of uncertainties and knowledge gaps regarding the "hiatus." This report reviews these issues and also posits insights from a collective set of diverse information that helps us understand what we do and do not know. One salient insight is that the GMST phenomenon is a surface characteristic that does not represent a slowdown in warming of the climate system but rather is an energy redistribution within the oceans. Improved understanding of the ocean distribution and redistribution of heat will help better monitor Earth's energy budget and its consequences. A review of recent scientific publications on the "hiatus" shows the difficulty and complexities in pinpointing the oceanic sink of the "missing heat" from the atmosphere and the upper layer of the oceans, which defines the "hiatus." Advances in "hiatus" research and outlooks (recommendations) are given in this report
Intermediate-mass black holes in Globular Clusters
For a sample of nine Galactic globular clusters we measured the inner
kinematic profiles with integral-field spectroscopy that we combined with
existing outer kinematic measurements and HST luminosity profiles. With this
information we are able to detect the crucial rise in the velocity-dispersion
profile which indicates the presence of a central black hole. In addition,
N-body simulations compared to our data will give us a deeper insight in the
properties of clusters with black holes and stronger selection criteria for
further studies. For the first time, we obtain a homogeneous sample of globular
cluster integral- field spectroscopy which allows a direct comparison between
clusters with and without an intermediate-mass black hole.Comment: 4 pages, 2 figures. To appear in the conference proceedings "Reading
the book of globular clusters with the lens of stellar evolution", Mem. S. A.
It. Eds. P. Ventura, C. Charbonnel, M. Castellani and M. Di Criscienz
The VIRUS-P Exploration of Nearby Galaxies (VENGA): Survey Design and First Results
VENGA is a large-scale extragalactic IFU survey, which maps the bulges, bars
and large parts of the outer disks of 32 nearby normal spiral galaxies. The
targets are chosen to span a wide range in Hubble types, star formation
activities, morphologies, and inclinations, at the same time of having vast
available multi-wavelength coverage from the far-UV to the mid-IR, and
available CO and 21cm mapping. The VENGA dataset will provide 2D maps of the
SFR, stellar and gas kinematics, chemical abundances, ISM density and
ionization states, dust extinction and stellar populations for these 32
galaxies. The uniqueness of the VIRUS-P large field of view permits these
large-scale mappings to be performed. VENGA will allow us to correlate all
these important quantities throughout the different environments present in
galactic disks, allowing the conduction of a large number of studies in star
formation, structure assembly, galactic feedback and ISM in galaxies.Comment: 7 pages, 3 figures, proceedings of the "Third Biennial Frank N. Bash
Symposium, New Horizons in Astronomy" held in Austin, TX, Oct. 2009. To be
published in the Astronomical Society of the Pacific Conference Series, eds.
L. Stanford, L. Hao, Y. Mao, J. Gree
The VIRUS-P Exploration of Nearby Galaxies (VENGA): Survey Design, Data Processing, and Spectral Analysis Methods
We present the survey design, data reduction, and spectral fitting pipeline
for the VIRUS-P Exploration of Nearby Galaxies (VENGA). VENGA is an integral
field spectroscopic survey, which maps the disks of 30 nearby spiral galaxies.
Targets span a wide range in Hubble type, star formation activity, morphology,
and inclination. The VENGA data-cubes have 5.6'' FWHM spatial resolution, ~5A
FWHM spectral resolution, sample the 3600A-6800A range, and cover large areas
typically sampling galaxies out to ~0.7 R_25. These data-cubes can be used to
produce 2D maps of the star formation rate, dust extinction, electron density,
stellar population parameters, the kinematics and chemical abundances of both
stars and ionized gas, and other physical quantities derived from the fitting
of the stellar spectrum and the measurement of nebular emission lines. To
exemplify our methods and the quality of the data, we present the VENGA
data-cube on the face-on Sc galaxy NGC 628 (a.k.a. M 74). The VENGA
observations of NGC 628 are described, as well as the construction of the
data-cube, our spectral fitting method, and the fitting of the stellar and
ionized gas velocity fields. We also propose a new method to measure the
inclination of nearly face-on systems based on the matching of the stellar and
gas rotation curves using asymmetric drift corrections. VENGA will measure
relevant physical parameters across different environments within these
galaxies, allowing a series of studies on star formation, structure assembly,
stellar populations, chemical evolution, galactic feedback, nuclear activity,
and the properties of the interstellar medium in massive disk galaxies.Comment: Accepted for publication in AJ, 25 pages, 18 figures, 6 table
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