43,093 research outputs found
Opening the Classroom Door - A Survey of Middle Grades Teachers Who Mentor Preservice Teachers— Lessons from Clinical Partnerships and Implications for Practice
Mentor teachers that participate in school-university clinical experiences have a unique opportunity to support preservice middle grades teachers’ development and improve the schooling of young adolescents. This article investigates an early clinical experience and presents data from a survey of 38 middle school teachers who served as mentor teachers. Findings address how middle grades teachers view their role as mentors, their perceptions of the clinical experience as a collaborative learning partnership, and concludes with suggestions to improve clinical experiences for preservice middle grades teacher candidates
The Birth of a Super Star Cluster: NGC 5253
We present images of the 7mm free-free emission from the radio "supernebula"
in NGC 5253 made with the Very Large Array and the Pie Town link. The images
reveal structure in the nebula, which has a <~ 1 pc (~50 mas radius) core
requiring the excitation of 1200 O7 stars. The nebula is elongated, with an arc
of emission curving to the northeast and to the south. The total ionizing flux
within the central 1.2" (~20 pc) is 7 x 10^52 s^-1, corresponding to 7000 O7
stars. We propose that the radio source is coincident with a small, very red
near-infrared cluster and apparently linked to a larger, optical source some 10
pc away on the sky. We speculate on the causes of this structure and what it
might tell us about the birth of the embedded young super star cluster.Comment: Accepted, Astrophysical Journal Letters. 10 pages, including 2
figure
Dense Molecular Filaments Feeding a Starburst: ALMA Maps of CO(3-2) in Henize 2-10
We present ALMA CO(3-2) observations at 0.3 arcsec resolution of He2-10, a
starburst dwarf galaxy and possible high-z galaxy analogue. The warm dense gas
traced by CO(3--2) is found in clumpy filaments that are kinematically and
spatially distinct. The filaments have no preferred orientation or direction;
this may indicate that the galaxy is not evolving into a disk galaxy. Filaments
appear to be feeding the active starburst; the velocity field in one filament
suggests acceleration onto an embedded star cluster. The relative strengths of
CO(3-2) and radio continuum vary strongly on decaparsec scales in the
starburst. There is no CO(3--2) clump coincident with the non-thermal radio
source that has been suggested to be an AGN, nor unusual kinematics.
The kinematics of the molecular gas show significant activity apparently
unrelated to the current starburst. The longest filament, east of the
starburst, has a pronounced shear of FWHM ~\kms\ across its 50~pc
width over its entire kpc length. The cause of the shear is not
clear. This filament is close in projection to a `dynamically distinct' CO
feature previously seen in CO(1--0). The most complex region and the most
highly disturbed gas velocities are in a region 200~pc south of the starburst.
The CO(3--2) emission there reveals a molecular outflow, of linewidth FWZI
120-140 \kms, requiring an energy . There is
at present {\it no} candidate for the driving source of this outflow.Comment: This was revised 31 October to correct some typos and to replace
Figure
The Extraordinary Infrared Spectrum of NGC 1222 (Mkn 603)
The infrared spectra of starburst galaxies are dominated by the
low-excitation lines of [NeII] and [SIII], and the stellar populations deduced
from these spectra appear to lack stars larger than about 35 Msun. The only
exceptions to this result until now were low metallicity dwarf galaxies. We
report our analysis of the mid-infrared spectra obtained with IRS on Spitzer of
the starburst galaxy NGC 1222 (Mkn 603). NGC 1222 is a large spheroidal galaxy
with a starburst nucleus that is a compact radio and infrared source, and its
infrared emission is dominated by the [NeIII] line. This is the first starburst
of solar or near-solar metallicity, known to us, which is dominated by the
high-excitation lines and which is a likely host of high mass stars. We model
the emission with several different assumptions as to the spatial distibution
of the high- and low-excitation lines and find that the upper mass cutoff in
this galaxy is 40-100 Msun.Comment: accepted, Astronomical Journal. 29 pp, 4 figures. In replacement
version an acknowledgment to NRAO is adde
The Economics of a Centralized Judiciary: Uniformity, Forum Shopping and the Federal Circuit
In 1982, the US Congress established the Court of Appeals for the Federal Circuit (CAFC) as the sole appellate court for patent cases. Ostensibly, this court was created to eliminate inconsistencies in the application and interpretation of patent law across federal courts, and thereby mitigate the incentives of patentees and alleged infringers to "forum shop" for a preferred venue. We perform the first econometric study of the extent of non-uniformity and forum shopping in the pre-CAFC era and of the CAFC's impact on these phenomena. We find that in patentee-plaintiff cases the pre-CAFC era was indeed characterized by significant non-uniformity in patent validity rates across circuits and by forum shopping on the basis of validity rates. We find weak evidence that the CAFC has increased uniformity of validity rates and strong evidence that forum shopping on the basis of validity rates ceased several years prior to the CAFC's establishment. In patentee-defendant cases, we find that validity rates are lower on average, but do not find either significant non-uniformity of validity rates across circuits or significant forum shopping.
Manual for extending the laser specklegram technique to strain analysis of rotating components
The theory, techniques, and equipment necessary for extending laser speckle techniques to analyze stresses in rotating blades are described. Details for setting up the equipment, for timing the events, for data recording, and for data analysis are discussed. Finite element techniques are investigated for analysis of speckle data. Advantages and limitations of the finite element analysis for the speckle data are discussed. The finite element program is listed
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