5,926 research outputs found
The Metadata Education and Research Information Commons (MERIC): A Collaborative Teaching and Research Initiative
The networked environment forced a sea change in Library and Information Science (LIS) education. Most LIS programs offer a mixed-mode of instruction that integrates online learning materials with more traditional classroom pedagogical methods and faculty are now responsible for developing content and digital learning objects. The teaching commons in a networked environment is one way to share, modify and repurpose learning objects while reducing the costs to educational institutions of developing course materials totally inhouse. It also provides a venue for sharing ideas, practices, and expertise in order to provide the best learning experience for students. Because metadata education has been impacted by rapid changes and metadata research is interdisciplinary and diffuse, the Metadata Education and Research Information Commons (MERIC) initiative aims to provide a virtual environment for sharing and collaboration within the extensive metadata community. This paper describes the development of MERIC from its origin as a simple clearinghouse proof-of-concept project to a service-oriented teaching and research commons prototype. The problems of enablers and barriers to participation and collaboration are discussed and the need for specific community building research is cited as critical for the success of MERIC within a broad metadata community
Anomaly-induced Quadrupole Moment of the Neutron in Magnetic Field
The neutrons cannot possess a quadrupole moment in the vacuum. Nevertheless,
we show that in the presence of an external magnetic field the neutrons acquire
a new type of quadrupole moment involving the
components of spin and magnetic field. This "chiral magnetic" quadrupole moment
arises from the interplay of the chiral anomaly and the magnetic field; we
estimate its value for the neutron in the static limit, and find . The detection of the quadrupole moment of the
neutron would provide a novel test of the role of the chiral anomaly in
low-energy QCD and can be possible in the presence of both magnetic and
inhomogeneous electric fields. The quadrupole moment of the neutron may affect
e.g. the properties of neutron stars and magnetars.Comment: 2 pages; extended versio
Technique for producing wind-tunnel heat-transfer models
Inexpensive thin skinned wind tunnel models with thermocouples on certain surface areas were fabricated. Thermocouples were designed for measuring aerodynamic heat transfer in wind tunnels
Chiral Electronics
We consider the properties of electric circuits involving Weyl semimetals.
The existence of the anomaly-induced chiral magnetic current in a Weyl
semimetal subjected to magnetic field causes an interesting and unusual
behavior of such circuits. We consider two explicit examples: i) a circuit
involving the "chiral battery" and ii) a circuit that can be used as a "quantum
amplifier" of magnetic field. The unique properties of these circuits stem from
the chiral anomaly and may be utilized for creating "chiral electronic"
devices.Comment: 5 pages, 2 figures; final version to appear in Physical Review
Star Formation in Cluster Galaxies at 0.2<z<0.55
The rest frame equivalent width of the [OII]3727 emission line, W(OII), has
been measured for cluster and field galaxies in the CNOC redshift survey of
rich clusters at 0.2<z<0.55. Emission lines of any strength in cluster galaxies
at all distances from the cluster centre, out to 2R_{200}, are less common than
in field galaxies. The mean W(OII) in cluster galaxies more luminous than
M_r^k<-18.5 + 5\log h (q_o=0.1) is 3.8 \pm 0.3 A (where the uncertainty is the
1 sigma error in the mean), significantly less than the field galaxy mean of
11.2 \pm 0.3 A. For the innermost cluster members (R<0.3R_{200}), the mean
W(OII) is only 0.3 \pm 0.4 A. Thus, it appears that neither the infall process
nor internal tides in the cluster induce detectable excess star formation in
cluster galaxies relative to the field. The colour-radius relation of the
sample is unable to fully account for the lack of cluster galaxies with
W(OII)>10 A, as expected in a model of cluster formation in which star
formation is truncated upon infall. Evidence of supressed star formation
relative to the field is present in the whole cluster sample, out to 2 R_{200},
so the mechanism responsible for the differential evolution must be acting at a
large distance from the cluster centre, and not just in the core. The mean star
formation rate in the cluster galaxies with the strongest emission corresponds
to an increase in the total stellar mass of less than about 4% if the star
formation is due to a secondary burst lasting 0.1 Gyr.Comment: aasms4 latex, 3 postscript figures, accepted for publication in ApJ
Letters. Also available at http://astrowww.phys.uvic.ca/~balogh
Survival Rates of Teeth with Primary Endodontic Treatment after Core/Post and Crown Placement
Introduction The objective of this study was to determine the effect of delayed placement of the core/post and crown on the outcomes of nonsurgical root canal therapy (NSRCT). Methods According to the Delta Dental of Wisconsin claims database, 160,040 NSRCTs were completed with a core/post and a crown placed before the end of the continuous coverage period or occurrence of an untoward event. Untoward events were defined as a retreatment, apicoectomy, or extraction as defined by the Code on Dental Procedures and Nomenclature. Statistical analysis was performed by using a multivariable Cox proportional hazards model. Results The survival rate from the time of crown placement to an untoward event was 99.1% at 1 year, 96.0% at 3 years, 92.3% at 5 years, and 83.8% at 10 years. Failure rates were greater when a core/post was placed more than 60 days after the NSRCT (adjusted hazard ratio, 1.08) and when the crown was placed more than 60 days after the core/post placement (adjusted hazard ratio, 1.14). Overall, the survival rates of NSRCT were greater when performed by an endodontist versus other providers. Conclusions On the basis of the information available from insurance claims data, this study shows that the long-term survival rates of initial endodontic therapy are adversely affected by the delayed placement of the final restoration and full coverage crown
Spectroscopy of moderately high-redshift RCS-1 clusters
We present spectroscopic observations of 11 moderately high-redshift (z~0.7-
1.0) clusters from the first Red-Sequence Cluster Survey (RCS-1). We find
excellent agreement between the red-sequence estimated redshift and the
spectroscopic redshift, with a scatter of 10% at z>0.7. At the high-redshift
end (z>~0.9) of the sample, we find two of the systems selected are projections
of pairs of comparably rich systems, with red-sequences too close to
discriminate in (R-z') colour. In one of these systems, the two components are
close enough to be physically associated. For a subsample of clusters with
sufficient spectroscopic members, we examine the correlation between B_gcR
(optical richness) and the dynamical mass inferred from the velocity
dispersion. We find these measurements to be compatible, within the relatively
large uncertainties, with the correlation established at lower redshift for the
X-ray selected CNOC1 clusters and also for a lower redshift sample of RCS-1
clusters. Confirmation of this and calibration of the scatter in the relation
will require larger samples of clusters at these and higher redshifts.
[abridged]Comment: AJ accepted. 30 pages, 7 figures (figure 5 reduced quality
Insulin-like Growth Factor Binding Protein Expression in Human Retinal Pigment Epithelial Cells
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73426/1/j.1749-6632.1993.tb26229.x.pd
Evaluation of tantalum for mercury containment in the SNAP-8 boiler
Corrosion testing of tantalum for mercury containment in SNAP 8 boile
Holographic Pomeron and the Schwinger Mechanism
We revisit the problem of dipole-dipole scattering via exchanges of soft
Pomerons in the context of holographic QCD. We show that a single closed string
exchange contribution to the eikonalized dipole-dipole scattering amplitude
yields a Regge behavior of the elastic amplitude; the corresponding slope and
intercept are different from previous results obtained by a variational
analysis of semi-classical surfaces. We provide a physical interpretation of
the semi-classical worldsheets driving the Regge behavior for (-t)>0 in terms
of worldsheet instantons. The latter describe the Schwinger mechanism for
string pair creation by an electric field, where the longitudinal electric
field E_L=\sigma_T tanh(\chi/2) at the origin of this non-perturbative
mechanism is induced by the relative rapidity {\chi} of the scattering dipoles.
Our analysis naturally explains the diffusion in the impact parameter space
encoded in the Pomeron exchange; in our picture, it is due to the Unruh
temperature of accelerated strings under the electric field. We also argue for
the existence of a "micro-fireball" in the middle of the transverse space due
to the soft Pomeron exchange, which may be at the origin of the thermal
character of multiparticle production in ep/pp collisions. After summing over
uncorrelated multi-Pomeron exchanges, we find that the total dipole-dipole
cross section obeys the Froissart unitarity bound.Comment: 17 pages, 4 figures, version 2: minor typos corrected, references
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