950 research outputs found
WS10.5 Comprehensive exercise training during hospitalization for an acute CF exacerbation: a randomized controlled trial
A Bezier curve-based generic shape encoder
Existing Bezier curve based shape description techniques primarily focus upon determining a set of pertinent Control Points (CP) to represent a particular shape contour. While many different approaches have been proposed, none adequately consider domain specific information about the shape contour like its gradualness and sharpness, in the CP generation process which can potentially result in large distortions in the objectââŹâ˘s shape representation. This paper introduces a novel Bezier Curve-based Generic Shape Encoder (BCGSE) that partitions an object contour into contiguous segments based upon its cornerity, before generating the CP for each segment using relevant shape curvature information. In addition, while CP encoding has generally been ignored, BCGSE embeds an efficient vertex-based encoding strategy exploiting the latent equidistance between consecutive CP. A nonlinear optimisation technique is also presented to enable the encoder is automatically adapt to bit-rate constraints. The performance of the BCGSE framework has been rigorously tested on a variety of diverse arbitrary shapes from both a distortion and requisite bit-rate perspective, with qualitative and quantitative results corroborating its superiority over existing shape descriptors
Pulse-mode quantum projection synthesis: Effects of mode mismatch on optical state truncation and preparation
Quantum projection synthesis can be used for phase-probability-distribution
measurement, optical-state truncation and preparation. The method relies on
interfering optical lights, which is a major challenge in experiments performed
by pulsed light sources. In the pulsed regime, the time frequency overlap of
the interfering lights plays a crucial role on the efficiency of the method
when they have different mode structures. In this paper, the pulsed mode
projection synthesis is developed, the mode structure of interfering lights are
characterized and the effect of this overlap (or mode match) on the fidelity of
optical-state truncation and preparation is investigated. By introducing the
positive-operator-valued measure (POVM) for the detection events in the scheme,
the effect of mode mismatch between the photon-counting detectors and the
incident lights are also presented.Comment: 11 pages, 4 figures, submitted to Phys. Rev.
Regulation of WNT Signaling by VSX2 During Optic Vesicle Patterning in Human Induced Pluripotent Stem Cells
Few gene targets of Visual System Homeobox 2 (VSX2) have been identified despite its broad and critical role in the maintenance of neural retina (NR) fate during early retinogenesis. We performed VSX2 ChIP-seq and ChIP-PCR assays on early stage optic vesicle-like structures (OVs) derived from human iPS cells (hiPSCs), which highlighted WNT pathway genes as direct regulatory targets of VSX2. Examination of early NR patterning in hiPSC-OVs from a patient with a functional null mutation in VSX2 revealed mis-expression and upregulation of WNT pathway components and retinal pigmented epithelium (RPE) markers in comparison to control hiPSCOVs. Furthermore, pharmacological inhibition of WNT signaling rescued the early mutant phenotype, whereas augmentation of WNT signaling in control hiPSC-OVs phenocopied the mutant. These findings reveal an important role for VSX2 as a regulator of WNT signaling and suggest that VSX2 may act to maintain NR identity at the expense of RPE in part by direct repression of WNT pathway constituents
Finding optimal strategies for minimum-error quantum-state discrimination
We propose a numerical algorithm for finding optimal measurements for
quantum-state discrimination. The theory of the semidefinite programming
provides a simple check of the optimality of the numerically obtained results.Comment: 4 pages, 2 figure
Hydrography and circulation near the crest of the East Pacific Rise between 9° and 10°N
Author Posting. Š The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 58 (2011): 365-376, doi:10.1016/j.dsr.2011.01.009.Topography has a strong effect on the physical oceanography over the flanks and crests of
the global mid-ocean ridge system. Here, we present an analysis of the hydrography and circulation near
the crest of the East Pacific Rise (EPR) between 9⌠and 10âŚN, which coincides with an integrated study site
(ISS) of the RIDGE2000 program. The analysis is based primarily on survey and mooring data collected
during the LADDER project, which aimed to investigate oceanographic and topographic influences on larval
retention and dispersal in hydrothermal vent communities. Results indicate that the yearly averaged regional
mean circulation is characterized by a westward drift of 0.5â1 cm¡sâ1 across the EPR axis and by north- and
southward flows along the western and eastern upper ridge flanks, respectively. The westward drift is part
of a basin-scale zonal flow that extends across most of the Pacific ocean near 10âŚN, whereas the meridional
currents near the ridge crest are a topographic effect. In spite of considerable mesoscale variability, which
dominates the regional circulation and dispersal on weekly to monthly time scales, quasi-synoptic surveys
carried out during the mooring deployment and recovery cruises indicate subinertial circulations that are
qualitatively similar to the yearly averaged flow but associated with significantly stronger velocities. Weekly
averaged mooring data indicate that the anticyclonically sheared along-flank flows are associated with core
speeds as high as 10 cm¡sâ1 and extend â10 km off axis and 200m above the ridge-crest topography. Near the
northern limit of the study region, the Lamont Seamount Chain rises from the western ridge flank and restricts
along-EPR flow to five narrow passages, where peak velocities in excess of 20 cm¡sâ1 were observed. Outside
the region of the ridge-crest boundary currents the density field over the EPR near 10âŚN is characterized by
isopycnals dipping into the ridge flanks. Directly above the EPR axis the ridge-crest boundary currents give
rise to an isopycnal dome. During times of strong westward cross-EPR flow isopycnal uplift over the eastern
flank causes the cross-ridge density field below the doming isopycnals to be asymmetric, with higher densities
over the eastern than over the western flank. The data collected during the LADDER project indicate that
dispersal of hydrothermal products from the EPR ISS on long time scales is predominantly to the west,
whereas mesoscale variability dominates dispersal on weekly to monthly time scales, which are particularly
important in the context of larval dispersal.Co-funding of the LADDER project by the biological and physical oceanography
divisions of the National Science Foundation under grants OCE-0425361 and OCE-0424953 is gratefully
acknowledged, as is support of J.W. Lavelle by NOAAâs Pacific Marine Environmental Laboratory and by the
NOAA Vents Program
Linear Response, Validity of Semi-Classical Gravity, and the Stability of Flat Space
A quantitative test for the validity of the semi-classical approximation in
gravity is given. The criterion proposed is that solutions to the
semi-classical Einstein equations should be stable to linearized perturbations,
in the sense that no gauge invariant perturbation should become unbounded in
time. A self-consistent linear response analysis of these perturbations, based
upon an invariant effective action principle, necessarily involves metric
fluctuations about the mean semi-classical geometry, and brings in the
two-point correlation function of the quantum energy-momentum tensor in a
natural way. This linear response equation contains no state dependent
divergences and requires no new renormalization counterterms beyond those
required in the leading order semi-classical approximation. The general linear
response criterion is applied to the specific example of a scalar field with
arbitrary mass and curvature coupling in the vacuum state of Minkowski
spacetime. The spectral representation of the vacuum polarization function is
computed in n dimensional Minkowski spacetime, and used to show that the flat
space solution to the semi-classical Einstein equations for n=4 is stable to
all perturbations on distance scales much larger than the Planck length.Comment: 22 pages: This is a significantly expanded version of gr-qc/0204083,
with two additional sections and two new appendices giving a complete,
explicit example of the semi-classical stability criterion proposed in the
previous pape
Population genomics of a predatory mammal reveals patterns of decline and impacts of exposure to toxic toads
Mammal declines across northern Australia are one of the major biodiversity loss events occurring globally. There has been no regional assessment of the implications of these species declines for genomic diversity. To address this, we conducted a species-wide assessment of genomic diversity in the northern quoll (Dasyurus hallucatus), an Endangered marsupial carnivore. We used next generation sequencing methods to genotype 10,191 single nucleotide polymorphisms (SNPs) in 352 individuals from across a 3220-km length of the continent, investigating patterns of population genomic structure and diversity, and identifying loci showing signals of putative selection. We found strong heterogeneity in the distribution of genomic diversity across the continent, characterized by (i) biogeographical barriers driving hierarchical population structure through long-term isolation, and (ii) severe reductions in diversity resulting from population declines, exacerbated by the spread of introduced toxic cane toads (Rhinella marina). These results warn of a large ongoing loss of genomic diversity and associated adaptive capacity as mammals decline across northern Australia. Encouragingly, populations of the northern quoll established on toad-free islands by translocations appear to have maintained most of the initial genomic diversity after 16âyears. By mapping patterns of genomic diversity within and among populations, and investigating these patterns in the context of population declines, we can provide conservation managers with data critical to informed decision-making. This includes the identification of populations that are candidates for genetic management, the importance of remnant island and insurance/translocated populations for the conservation of genetic diversity, and the characterization of putative evolutionarily significant units
Use of comprehensive recruitment strategies in the glycemia reduction approaches in diabetes: A comparative effectiveness study (GRADE) multi-center clinical trial
Background/Aims: We present and describe recruitment strategies implemented from 2013 to 2017 across 45 clinical sites in the United States, participating in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study, an unmasked, randomized controlled trial evaluating four glucose-lowering medications added to metformin in individuals with type 2 diabetes mellitus (duration of diabetes <10 years). We examined the yield of participants recruited through Electronic Health Records systems compared to traditional recruitment methods to leverage access to type 2 diabetes patients in primary care. Methods: Site selection criteria included availability of the study population, geographic representation, the ability to recruit and retain a diverse pool of participants including traditionally underrepresented groups, and prior site research experience in diabetes clinical trials. Recruitment initiatives were employed to support and monitor recruitment, such as creation of a Recruitment and Retention Committee, development of criteria for Electronic Health Record systems queries, conduct of remote site visits, development of a public screening website, and other central and local initiatives. Notably, the study supported a dedicated recruitment coordinator at each site to manage local recruitment and facilitate screening of potential participants identified by Electronic Health Record systems. Results: The study achieved the enrollment goal of 5000 participants, meeting its target with Black/African American (20%), Hispanic/Latino (18%), and age â§60 years (42%) subgroups but not with women (36%). Recruitment required 1 year more than the 3 years originally planned. Sites included academic hospitals, integrated health systems, and Veterans Affairs Medical Centers. Participants were enrolled through Electronic Health Record queries (68%), physician referral (13%), traditional mail outreach (7%), TV, radio, flyers, and Internet (7%), and other strategies (5%). Early implementation of targeted Electronic Health Record queries yielded a greater number of eligible participants compared to other recruitment methods. Efforts over time increasingly emphasized engagement with primary care networks. Conclusion: Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness successfully recruited a diverse study population with relatively new onset of type 2 diabetes mellitus, relying to a large extent on the use of Electronic Health Record to screen potential participants. A comprehensive approach to recruitment with frequent monitoring was critical to meet the recruitment goal
- âŚ