2,601 research outputs found
Teacher Quality and Quality Teaching: Examining the Relationship of a Teacher Assessment to Practice
Innovative Intelligent Services for Supporting Cognitively Impaired Older Adults and Their Caregivers
The redshift distribution of dusty star forming galaxies from the SPT survey
We use the Atacama Large Millimeter/submillimeter Array (ALMA) in Cycle 1 to
determine spectroscopic redshifts of high-redshift dusty star-forming galaxies
(DSFGs) selected by their 1.4mm continuum emission in the South Pole Telescope
(SPT) survey. We present ALMA 3mm spectral scans between 84-114GHz for 15
galaxies and targeted ALMA 1mm observations for an additional eight sources.
Our observations yield 30 new line detections from CO, [CI] , [NII] , H_2O and
NH_3. We further present APEX [CII] and CO mid-J observations for seven sources
for which only a single line was detected in spectral-scan data from ALMA Cycle
0 or Cycle 1. We combine the new observations with previously published and new
mm/submm line and photometric data of the SPT-selected DSFGs to study their
redshift distribution. The combined data yield 39 spectroscopic redshifts from
molecular lines, a success rate of >85%. Our sample represents the largest data
set of its kind today and has the highest spectroscopic completeness among all
redshift surveys of high-z DSFGs. The median of the redshift distribution is
z=3.9+/-0.4, and the highest-redshift source in our sample is at z=5.8. We
discuss how the selection of our sources affects the redshift distribution,
focusing on source brightness, selection wavelength, and strong gravitational
lensing. We correct for the effect of gravitational lensing and find the
redshift distribution for 1.4mm-selected sources with a median redshift of
z=3.1+/-0.3. Comparing to redshift distributions selected at shorter
wavelengths from the literature, we show that selection wavelength affects the
shape of the redshift distribution
Examining High and Low Value-Added Mathematics Instruction: Can Expert Observers Tell the Difference
The question of how to measure effective teachers and teaching has long been of interest to policymakers and school leaders. While recent policy initiatives have focused on the use of value-added measures (VAM) to assess teacher quality, there is a much longer tradition of using observations of practice to make such determinations. However, empirical evidence suggests these two indicators often identify different sets of teachers as effective. For example, the Measures of Effective Teaching project finds low correlations between teachersâ VAM scores and their quality of instruction as measured by observational metrics. Studies with the explicit intent of identifying differences in instruction between teachers with high and low VAM scores also have generally failed to uncover substantial differences across classrooms.
In this study, we take advantage of a dataset containing both videotaped lessons and value-added scores to mount an exploratory study of the instruction of teachers with high- and low-value-added rankings. Specifically, we seek to answer two questions: First, what is the degree of convergence between observersâ impressions of mathematics instruction and teachersâ mathematics value-added scores? Second, are there a set of instructional practices that consistently characterize high but not low-value-added ranked teachersâ classrooms, and vice versa
Fast, scalable, Bayesian spike identification for multi-electrode arrays
We present an algorithm to identify individual neural spikes observed on
high-density multi-electrode arrays (MEAs). Our method can distinguish large
numbers of distinct neural units, even when spikes overlap, and accounts for
intrinsic variability of spikes from each unit. As MEAs grow larger, it is
important to find spike-identification methods that are scalable, that is, the
computational cost of spike fitting should scale well with the number of units
observed. Our algorithm accomplishes this goal, and is fast, because it
exploits the spatial locality of each unit and the basic biophysics of
extracellular signal propagation. Human intervention is minimized and
streamlined via a graphical interface. We illustrate our method on data from a
mammalian retina preparation and document its performance on simulated data
consisting of spikes added to experimentally measured background noise. The
algorithm is highly accurate
ALMA Observations of the Sub-kpc Structure of the Host Galaxy of a z= 6.5 Lensed Quasar: A Rotationally-Supported Hyper-Starburst System at the Epoch of Reionization
We report ALMA observations of the dust continuum and {\cii} emission of the
host galaxy of J0439+1634, a gravitationally lensed quasar at .
Gravitational lensing boosts the source-plane resolution to \sim0\farcs15
. The lensing model derived from the ALMA data is
consistent with the fiducial model in \citet{fan19} based on {\it HST} imaging.
The host galaxy of J0439+1634 can be well-fitted by a S\'ersic profile
consistent with an exponential disk, both in the far-infrared (FIR) continuum
and the {\cii} emission. The overall magnification is for the
continuum and for the {\cii} line. The host galaxy of J0439+1634
is a compact ultra-luminous infrared galaxy, with a total star formation rate
(SFR) of after correcting for lensing and
an effective radius of kpc. The resolved regions in J0439+1634 follow
the ``{\cii} deficit," where the {\cii}-to-FIR ratio decreases with FIR surface
brightness. The reconstructed velocity field of J0439+1634 appears to be
rotation-like. The maximum line-of-sight rotation velocity of 130 km/s at a
radius of 2 kpc. However, our data cannot be fit by an axisymmetric thin
rotating disk, and the inclination of the rotation axis, , remains
unconstrained. We estimate the dynamical mass of the host galaxy to be
. J0439+1634 is likely to have a high
gas-mass fraction and an oversized SMBH compared to local relations. The SFR of
J0439+1634 reaches the maximum possible values, and the SFR surface density is
close to the highest value seen in any star-forming galaxy currently known in
the universe.Comment: 14 pages, 7 figures. Accepted by Ap
An inclusive search for free quarks at PEP
Abstract We report the results of a search for fractionally charged particles in e + e â reactions at a center of mass energy of 29 GeV. We find no evidence for such particles and present upper limitts on R q = Ï q q X/Ï ÎŒÎŒ for change 1 3 e and 2 3 e which range from 1 to 8 Ă 10 â2 for mass up to 12 GeV/ c 2
Search for CP Violation in the Decay Z -> b (b bar) g
About three million hadronic decays of the Z collected by ALEPH in the years
1991-1994 are used to search for anomalous CP violation beyond the Standard
Model in the decay Z -> b \bar{b} g. The study is performed by analyzing
angular correlations between the two quarks and the gluon in three-jet events
and by measuring the differential two-jet rate. No signal of CP violation is
found. For the combinations of anomalous CP violating couplings, and , limits of \hat{h}_b < 0.59h^{\ast}_{b} < 3.02$ are given at 95\% CL.Comment: 8 pages, 1 postscript figure, uses here.sty, epsfig.st
Search for fractionally charged particles in cosmic rays at large zenith angles
We have performed a single-particle search for fractional charge in cosmic rays having residual ranges at sea level >250 g/cm/sup 2/ concrete and zenith angles between 45/sup 0/ and 90/sup 0/. The detector is a hodoscope of 24 layers of plastic scintillator, eight layers of multiwire proportional chambers, and two layers of lucite Cherenkov counters. The acceptance of the instrument is 4.0 x 10/sup 3/ cm/sup 2/sr. An analysis of 3.5 x 10/sup 6/ triggers during a running time of 8 x 10/sup 5/ sec yields no particles with charge Q = (1/3) or Q = (2/3) and velocities greater than roughly-equal0.1c. We deduce an upper limit on the flux of fractionally charged particles of 8.5 x 10/sup -10/ (cm/sup 2/sr sec)/sup -1/ for relativistic Q = (1/3) and 7.6 x 10/sup -10/ (cm/sup 2/sr sec)/sup -1/ for Q = (2/3)
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