3,793 research outputs found
Hubble Frontier Field Free-Form Mass Mapping of the Massive Multiple-Merging Cluster MACSJ0717.5+3745
We examine the latest data on the cluster MACSJ0717.5+3745 from the Hubble
Frontier Fields campaign. The critically lensed area is the largest known of
any lens and very irregular making it a challenge for parametric modelling.
Using our Free-Form method we obtain an accurate solution, identify here many
new sets of multiple images, doubling the number of constraints and improving
the reconstruction of the dark matter distribution. Our reconstructed mass map
shows several distinct central substructures with shallow density profiles,
clarifying earlier work and defining well the relation between the dark matter
distribution and the luminous and X-ray peaks within the critically lensed
region. Using our free-form method, we are able to meaningfully subtract the
mass contribution from cluster members to the deflection field to trace the
smoothly distributed cluster dark matter distribution. We find 4 distinct
concentrations, 3 of which are coincident with the luminous matter. The fourth
peak has a significant offset from both the closest luminous and X-ray peaks.
These findings, together with dynamical data from the motions of galaxies and
gas will be important for uncovering the potentially important implications of
this extremely massive and intriguing system.Comment: 16 pages, 10 figures, 2 tables. Matches the verson submitted to
mnras. New table (A2) included with additional system candidate
A Rigorous Free-form Lens Model of Abell 2744 to Meet the Hubble Frontier Fields Challenge
Hubble Frontier Fields (HFF) imaging of the most powerful lensing clusters
provides access to the most magnified distant galaxies. The challenge is to
construct lens models capable of describing these complex massive, merging
clusters so that individual lensed systems can be reliably identified and their
intrinsic properties accurately derived. We apply the free-form lensing method
(WSLAP+) to A2744, providing a model independent map of the cluster mass,
magnification, and geometric distance estimates to multiply-lensed sources. We
solve simultaneously for a smooth cluster component on a pixel grid, together
with local deflections by the cluster member galaxies. Combining model
prediction with photometric redshift measurements, we correct and complete
several systems recently claimed, and identify 4 new systems - totalling 65
images of 21 systems spanning a redshift range of 1.4<z<9.8. The reconstructed
mass shows small enhancements in the directions where significant amounts of
hot plasma can be seen in X-ray. We compare photometric redshifts with
"geometric redshifts", finding a high level of self-consistency. We find
excellent agreement between predicted and observed fluxes - with a best-fit
slope of 0.999+-0.013 and an RMS of ~0.25 mag, demonstrating that our
magnification correction of the lensed background galaxies is very reliable.
Intriguingly, few multiply-lensed galaxies are detected beyond z~7.0, despite
the high magnification and the limiting redshift of z~11.5 permitted by the HFF
filters. With the additional HFF clusters we can better examine the
plausibility of any pronounced high-z deficit, with potentially important
implications for the reionization epoch and the nature of dark matter.Comment: Accepted for publication in ApJ with newly identified lensed images
in complete HFF dat
Vortex ring refraction at large Froude numbers
We have experimentally studied the impact of an initially planar axisymmetric
vortex ring, incident at an oblique angle, upon a gravity-induced interface
separating two fluids of differing densities. After impact, the vortex ring was
found to exhibit a variety of subsequent trajectories, which we organize
according to both the incidence angle, , and the interface strength,
defined as the ratio of the Atwood and Froude numbers, . For grazing
incidence angles ( deg.) vortices either penetrate or
reflect from the interface, depending on whether the interface is weak or
strong. In some cases, reflected vortices execute damped oscillations before
finally disintegrating. For smaller incidence angles (
deg.) vortices penetrate the interface. When there is a strong interface, these
vortices are observed to curve back up toward the interface. When there is a
weak interface, these vortices are observed to refract downward, away from the
interface. The critical interface strength below which vortex ring refraction
is observed is given by .Comment: 26 pages, 11 figures; Submitted to Physical Review
A Free-Form Prediction for the Reappearance of Supernova Refsdal in the Hubble Frontier Fields Cluster MACSJ1149.5+2223
The massive cluster MACSJ1149.5+2223(z=0.544) displays five very large lensed
images of a well resolved spiral galaxy at . It is within
one of these images that the first example of a multiply-lensed supernova has
been detected recently as part of the Grism Lens-Amplified Survey from Space.
The depth of this data also reveals many HII regions within the lensed spiral
galaxy which we identify between the five counter-images. Here we expand the
capability of our free-form method to incorporate these HII regions locally,
with other reliable lensed galaxies added for a global solution. This improved
accuracy allows us to estimate when the Refsdal supernova will appear within
the other lensed images of the spiral galaxy to an accuracy of 7\%. We
predict this supernova will reappear in one of the counter-images
(RA=11:49:36.025, DEC=+22:23:48.11, J2000) and on November 1 2015 (with
an estimated error of 25 days) it will be at the same phase as it was
when it was originally discovered, offering a unique opportunity to study the
early phases of this supernova and to examine the consistency of the mass model
and the cosmological model that have an impact on the time delay prediction.Comment: 12 images, 11 pages. Mateches accepted version in MNRAS. MNRAS in
pres
Data Quality Over Quantity: Pitfalls and Guidelines for Process Analytics
A significant portion of the effort involved in advanced process control,
process analytics, and machine learning involves acquiring and preparing data.
Literature often emphasizes increasingly complex modelling techniques with
incremental performance improvements. However, when industrial case studies are
published they often lack important details on data acquisition and
preparation. Although data pre-processing is unfairly maligned as trivial and
technically uninteresting, in practice it has an out-sized influence on the
success of real-world artificial intelligence applications. This work describes
best practices for acquiring and preparing operating data to pursue data-driven
modelling and control opportunities in industrial processes. We present
practical considerations for pre-processing industrial time series data to
inform the efficient development of reliable soft sensors that provide valuable
process insights.Comment: This work has been accepted to the 22nd IFAC World Congress 202
DNA hybridization to mismatched templates: a chip study
High-density oligonucleotide arrays are among the most rapidly expanding
technologies in biology today. In the {\sl GeneChip} system, the reconstruction
of the target concentration depends upon the differential signal generated from
hybridizing the target RNA to two nearly identical templates: a perfect match
(PM) and a single mismatch (MM) probe. It has been observed that a large
fraction of MM probes repeatably bind targets better than the PMs, against the
usual expectation from sequence-specific hybridization; this is difficult to
interpret in terms of the underlying physics. We examine this problem via a
statistical analysis of a large set of microarray experiments. We classify the
probes according to their signal to noise () ratio, defined as the
eccentricity of a (PM, MM) pair's `trajectory' across many experiments. Of
those probes having large () only a fraction behave consistently with
the commonly assumed hybridization model. Our results imply that the physics of
DNA hybridization in microarrays is more complex than expected, and they
suggest new ways of constructing estimators for the target RNA concentration.Comment: 3 figures 1 tabl
Results of ASERTAA, a randomized prospective crossover pharmacogenetic study of immediate-release versus extended-release tacrolimus in African American kidney transplant recipients
BACKGROUND: Differences in tacrolimus dosing across ancestries is partly attributable to polymorphisms in CYP3A5 genes that encode tacrolimus-metabolizing cytochrome P450 3A5 enzymes. The CYP3A5*1 allele, preponderant in African Americans, is associated with rapid metabolism, subtherapeutic concentrations, and higher dose requirements for tacrolimus, all contributing to worse outcomes. Little is known about the relationship between CYP3A5 genotype and the tacrolimus pharmacokinetic area under the curve (AUC) profile in African Americans or whether pharmacogenetic differences exist between conventional twice-daily, rapidly absorbed, immediate-release tacrolimus (IR-Tac) and once-daily extended-release tacrolimus (LifeCycle Pharma Tac [LCPT]) with a delayed absorption profile.
STUDY DESIGN: Randomized prospective crossover study.
SETTING & PARTICIPANTS: 50 African American maintenance kidney recipients on stable IR-Tac dosing.
INTERVENTION: Recipients were randomly assigned to continue IR-Tac on days 1 to 7 and then switch to LCPT on day 8 or receive LCPT on days 1 to 7 and then switch to IR-Tac on day 8. The LCPT dose was 85% of the IR-Tac total daily dose.
OUTCOMES: Tacrolimus 24-hour AUC (AUC
MEASUREMENTS: CYP3A5 genotype, 24-hour tacrolimus pharmacokinetic profiles.
RESULTS: ∼80% of participants carried the CYP3A5*1 allele (CYP3A5 expressers). There were no significant differences in AUC
LIMITATIONS: This was primarily a pharmacogenetic study rather than an efficacy study; the follow-up period was too short to capture clinical outcomes.
CONCLUSIONS: Achieving therapeutic tacrolimus trough concentrations with IR-Tac in most African Americans results in significantly higher peak concentrations, potentially magnifying the risk for toxicity and adverse outcomes. This pharmacogenetic effect is attenuated by delayed tacrolimus absorption with LCPT.
TRIAL REGISTRATION: Registered at ClinicalTrials.gov, with study number NCT01962922
Improved DIQKD protocols with finite-size analysis
The security of finite-length keys is essential for the implementation of
device-independent quantum key distribution (DIQKD). Presently, there are
several finite-size DIQKD security proofs, but they are mostly focused on
standard DIQKD protocols and do not directly apply to the recent improved DIQKD
protocols based on noisy preprocessing, random key measurements, and modified
CHSH inequalities. Here, we provide a general finite-size security proof that
can simultaneously encompass these approaches, using tighter finite-size bounds
than previous analyses. In doing so, we develop a method to compute tight lower
bounds on the asymptotic keyrate for any such DIQKD protocol with binary inputs
and outputs. With this, we show that positive asymptotic keyrates are
achievable up to depolarizing noise values of , exceeding all
previously known noise thresholds. We also develop a modification to
random-key-measurement protocols, using a pre-shared seed followed by a "seed
recovery" step, which yields substantially higher net key generation rates by
essentially removing the sifting factor. Some of our results may also improve
the keyrates of device-independent randomness expansion.Comment: Improved threshold with more data points, discussion of conjecture in
[SGP+21], correction regarding results of [MDR+19
Moving towards a cure in genetics : what is needed to bring somatic gene therapy to the clinic?
Clinical trials using somatic gene editing (e.g., CRISPR-Cas9) have started in Europe and the United States and may provide safe and effective treatment and cure, not only for cancers but also for some monogenic conditions. In a workshop at the 2018 European Human Genetics Conference, the challenges of bringing somatic gene editing therapies to the clinic were discussed. The regulatory process needs to be considered early in the clinical development pathway to produce the data necessary to support the approval by the European Medicines Agency. The roles and responsibilities for geneticists may include counselling to explain the treatment possibilities and safety interpretation.Peer reviewe
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