7,336 research outputs found
Multipartite Entangled Spatial Modes of Ultracold Atoms Generated and Controlled by Quantum Measurement
We show that the effect of measurement back-action results in the generation
of multiple many-body spatial modes of ultracold atoms trapped in an optical
lattice, when scattered light is detected. The multipartite mode entanglement
properties and their nontrivial spatial overlap can be varied by tuning the
optical geometry in a single setup. This can be used to engineer quantum states
and dynamics of matter fields. We provide examples of multimode generalizations
of parametric down-conversion, Dicke, and other states, investigate the
entanglement properties of such states, and show how they can be transformed
into a class of generalized squeezed states. Further, we propose how these
modes can be used to detect and measure entanglement in quantum gases.Comment: 6 Pages, 3 Figures, Supplemental Material include
Less harmful acidic degradation of poly(lactic-co-glycolic acid) bone tissue engineering scaffolds through titania nanoparticle addition
In the last 10 years, biodegradable aliphatic polyesters, such as poly(lactic-co-glycolic acid) (PLGA), have attracted increasing attention for their use as scaffold materials in bone tissue engineering because their degradation products can be removed by natural metabolic pathways. However, one main concern with the use of these specific polymers is that their degradation products reduce local pH, which in turn induces an inflammatory reaction and damages bone cell health at the implant site. Thus, the objective of the present in vitro study was to investigate the degradation behavior of PLGA when added with dispersed titania nanoparticles. The results of this study provided the first evidence that the increased dispersion of nanophase titania in PLGA decreased the harmful change in pH normal for PLGA degradation. Moreover, previous studies have demonstrated that the increased dispersion of titania nanoparticles into PLGA significantly improved osteoblast (bone-forming cell) functions (such as adhesion, collagen synthesis, alkaline phosphatase activity, and calcium-containing minerals deposition). In this manner, nanophase titania–PLGA composites may be promising scaffold materials for more effective orthopedic tissue engineering applications
Is There a General Motor Program for Right Versus Left Hand Throwing in Children?
The purpose of this study was to determine if a general motor program controlled some or all aspects of overhand throwing. Using a 12 camera Vicon motion analysis system to record data from body markers, a group of 30 Australian Aboriginal children 6-10 years of age threw with maximal effort into a large target area. Data were reduced and analysed for numerous variables and correlations were calculated between dominant and non-dominant side variables that were deemed reliable. Results indicated that five variables showed significant dominant to non-dominant correlations. However, only two of the five were entered into both multiple regressions to predict horizontal ball velocity for the dominant vs. non-dominant sides. The variables entered suggested that more gross aspects of the movement (stride distance and pelvis flexion) were both correlated from dominant to non-dominant sides and predicted horizontal ball velocity. Thus, the general motor program does not appear to control the more complex and coordinated parts of the throwing motion
The views of health guideline developers on the use of automation in health evidence synthesis
BACKGROUND: The increasingly rapid rate of evidence publication has made it difficult for evidence synthesis-systematic reviews and health guidelines-to be continually kept up to date. One proposed solution for this is the use of automation in health evidence synthesis. Guideline developers are key gatekeepers in the acceptance and use of evidence, and therefore, their opinions on the potential use of automation are crucial. METHODS: The objective of this study was to analyze the attitudes of guideline developers towards the use of automation in health evidence synthesis. The Diffusion of Innovations framework was chosen as an initial analytical framework because it encapsulates some of the core issues which are thought to affect the adoption of new innovations in practice. This well-established theory posits five dimensions which affect the adoption of novel technologies: Relative Advantage, Compatibility, Complexity, Trialability, and Observability. Eighteen interviews were conducted with individuals who were currently working, or had previously worked, in guideline development. After transcription, a multiphase mixed deductive and grounded approach was used to analyze the data. First, transcripts were coded with a deductive approach using Rogers' Diffusion of Innovation as the top-level themes. Second, sub-themes within the framework were identified using a grounded approach. RESULTS: Participants were consistently most concerned with the extent to which an innovation is in line with current values and practices (i.e., Compatibility in the Diffusion of Innovations framework). Participants were also concerned with Relative Advantage and Observability, which were discussed in approximately equal amounts. For the latter, participants expressed a desire for transparency in the methodology of automation software. Participants were noticeably less interested in Complexity and Trialability, which were discussed infrequently. These results were reasonably consistent across all participants. CONCLUSIONS: If machine learning and other automation technologies are to be used more widely and to their full potential in systematic reviews and guideline development, it is crucial to ensure new technologies are in line with current values and practice. It will also be important to maximize the transparency of the methods of these technologies to address the concerns of guideline developers
Quantifying the Origin and Distribution of Intracluster Light in a Fornax-like Cluster
Using a cosmological -body simulation, we investigate the origin and
distribution of stars in the intracluster light (ICL) of a Fornax-like cluster.
In a dark matter only simulation we identify a halo which, at , has and , and replace infalling
subhalos with models that include spheroid and disc components. As they fall
into the cluster, the stars in some of these galaxies are stripped from their
hosts, and form the ICL. We consider the separate contributions to the ICL from
stars which originate in the haloes and the discs of the galaxies. We find that
disc ICL stars are more centrally concentrated than halo ICL stars. The
majority of the disc ICL stars are associated with one initially disc-dominated
galaxy that falls to the centre of the cluster and is heavily disrupted,
producing part of the cD galaxy. At radial distances greater than 200kpc, well
beyond the stellar envelope of the cD galaxy, stars formerly from the stellar
haloes of galaxies dominate the ICL. Therefore at large distances, the ICL
population is dominated by older stars.Comment: Paper published as MNRAS , 2017, 467, 4501 This version corrects a
small typo in the authors fiel
Gamma-Ray Bursts Trace UV Metrics of Star Formation over 3 < z < 5
We present the first uniform treatment of long duration gamma-ray burst (GRB)
host galaxy detections and upper limits over the redshift range 3<z<5, a key
epoch for observational and theoretical efforts to understand the processes,
environments, and consequences of early cosmic star formation. We contribute
deep imaging observations of 13 GRB positions yielding the discovery of eight
new host galaxies. We use this dataset in tandem with previously published
observations of 31 further GRB positions to estimate or constrain the host
galaxy rest-frame ultraviolet (UV; 1600 A) absolute magnitudes M_UV. We then
use the combined set of 44 M_UV estimates and limits to construct the M_UV
luminosity function (LF) for GRB host galaxies over 3<z<5 and compare it to
expectations from Lyman break galaxy (LBG) photometric surveys with the Hubble
Space Telescope. Adopting standard prescriptions for the luminosity dependence
of galaxy dust obscuration (and hence, total star formation rate), we find that
our LF is compatible with LBG observations over a factor of 600x in host
luminosity, from M_UV = -22.5 mag to >-15.6 mag, and with extrapolations of the
assumed Schechter-type LF well beyond this range. We review proposed
astrophysical and observational biases for our sample, and find they are for
the most part minimal. We therefore conclude, as the simplest interpretation of
our results, that GRBs successfully trace UV metrics of cosmic star formation
over the range 3<z<5. Our findings suggest GRBs are providing an accurate
picture of star formation processes from z ~3 out to the highest redshifts.Comment: publ. ApJ 809 (2015) 76; 14 figures; replacement to reflect changes
to v1 (rounding effects, diff. LF from Bouwens
High-resolution Multi-band Imaging for Validation and Characterization of Small Kepler Planets
High-resolution ground-based optical speckle and near-infrared adaptive
optics images are taken to search for stars in close angular proximity to host
stars of candidate planets identified by the NASA Kepler Mission. Neighboring
stars are a potential source of false positive signals. These stars also blend
into Kepler light curves, affecting estimated planet properties, and are
important for an understanding of planets in multiple star systems. Deep images
with high angular resolution help to validate candidate planets by excluding
potential background eclipsing binaries as the source of the transit signals. A
study of 18 Kepler Object of Interest stars hosting a total of 28 candidate and
validated planets is presented. Validation levels are determined for 18 planets
against the likelihood of a false positive from a background eclipsing binary.
Most of these are validated at the 99% level or higher, including 5
newly-validated planets in two systems: Kepler-430 and Kepler-431. The stellar
properties of the candidate host stars are determined by supplementing existing
literature values with new spectroscopic characterizations. Close neighbors of
7 of these stars are examined using multi-wavelength photometry to determine
their nature and influence on the candidate planet properties. Most of the
close neighbors appear to be gravitationally-bound secondaries, while a few are
best explained as closely co-aligned field stars. Revised planet properties are
derived for each candidate and validated planet, including cases where the
close neighbors are the potential host stars.Comment: in press at AJ, 44 pages, 8 figures; The only changes made relative
to version 1 are updates to the list of reference
Proclamation by Kentucky Governor Thomas E. Bramlette and Others
The broadside features information regarding the Kentucky elections and allegiance to the U.S. during the American Civil War. It is printed on cream paper and with black ink. It has some tears at its edges and water damage at its top and bottom.https://scholarsjunction.msstate.edu/fvw-artifacts/1094/thumbnail.jp
Proclamation by Kentucky Governor Thomas E. Bramlette and Others
The broadside features information regarding the Kentucky elections and allegiance to the U.S. during the American Civil War. It is printed on cream paper and with black ink. It has some tears at its edges and water damage at its top and bottom.https://scholarsjunction.msstate.edu/fvw-ephemera/1021/thumbnail.jp
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