497 research outputs found
Engineering Quantum States, Nonlinear Measurements, and Anomalous Diffusion by Imaging
We show that well-separated quantum superposition states, measurements of
strongly nonlinear observables, and quantum dynamics driven by anomalous
diffusion can all be achieved for single atoms or molecules by imaging
spontaneous photons that they emit via resonance florescence. To generate
anomalous diffusion we introduce continuous measurements driven by L\'evy
processes, and prove a number of results regarding their properties. In
particular we present strong evidence that the only stable L\'evy density that
can realize a strictly continuous measurement is the Gaussian.Comment: revtex4-1, 17 pages, 7 eps figure
Field evaluation of the efficacy and safety of a combination of spinosad and milbemycin oxime in the treatment and prevention of naturally acquired flea infestations and treatment of intestinal nematode infections in dogs in Europe
AbstractTwo separate randomised, blinded, multicentre field trials were conducted to evaluate the efficacy and safety of a combination of spinosad and milbemycin oxime (MO) (Trifexis®, Elanco Animal Health) in the treatment and prevention of naturally acquired flea infestations and intestinal nematode infections in European dogs. Treatments using Trifexis® and each control veterinary product (CVP) were administered once on Day 0 in both field studies.In the flea field trial, 11 veterinary clinics in France participated in the study. On Day 0, whole body flea comb counts were conducted on all dogs being evaluated for enrolment. Dogs with ≥7 fleas on Day 0 were enrolled, treated once on Day 0 with spinosad/MO or the CVP (Stronghold®; selamectin) and then underwent post-treatment flea counts on Days 14 and 30. There were 150 spinosad/MO treated dogs and 71 CVP treated dogs included in the flea effectiveness population. Effectiveness against fleas (% reduction in geometric means; GM) was 98.97% and 97.37% for the spinosad/MO treated dogs, and 97.43% and 93.96% for the CVP dogs on Days 14 and 30, respectively, compared to the pre-treatment baseline flea counts. Of the spinosad/MO dogs, 89.3% and 80.0% had no live fleas on Days 14 and 30, compared to 77.5% and 70.4% of the CVP dogs, respectively.In the nematode field trial, data from 10 veterinary clinics in France and 19 in Ireland were pooled. Faecal samples from dogs at each clinic were analysed. A positive result at screening (parasite eggs from Toxocara canis, Toxascaris leonina, Trichuris vulpis or Ancylostoma caninum) allowed for enrolment. Dogs were randomised to spinosad/MO or the CVP (Milbemax®; MO/praziquantel). On Day 8, a post-treatment faecal sample was taken and analysed. Of 2333 dogs screened for nematode eggs, 238 dogs were positive with one or more of these nematodes, and 229 were enrolled in the study. Of the 229 dogs, 151 were treated with a single dose of spinosad/MO, and 77 were treated with a single dose of CVP. Post-treatment effectiveness against all nematodes (% reduction GM) was achieved with reductions of 98.57% and 97.57% for the spinosad/MO treated dogs and CVP dogs, respectively, as compared to the pre-treatment baseline faecal egg counts.Trifexis® was shown to be safe and effective against natural infestations of fleas as well as mixed and single intestinal nematode infections in client owned dogs in Europe when administered as a single oral administration at the recommended dose
Atom laser coherence and its control via feedback
We present a quantum-mechanical treatment of the coherence properties of a
single-mode atom laser. Specifically, we focus on the quantum phase noise of
the atomic field as expressed by the first-order coherence function, for which
we derive analytical expressions in various regimes. The decay of this function
is characterized by the coherence time, or its reciprocal, the linewidth. A
crucial contributor to the linewidth is the collisional interaction of the
atoms. We find four distinct regimes for the linewidth with increasing
interaction strength. These range from the standard laser linewidth, through
quadratic and linear regimes, to another constant regime due to quantum
revivals of the coherence function. The laser output is only coherent (Bose
degenerate) up to the linear regime. However, we show that application of a
quantum nondemolition measurement and feedback scheme will increase, by many
orders of magnitude, the range of interaction strengths for which it remains
coherent.Comment: 15 pages, 6 figures, revtex
The Dynamic Interface Between the Bone Marrow Vascular Niche and Hematopoietic Stem Cells in Myeloid Malignancy
Hematopoietic stem cells interact with bone marrow niches, including highly specialized blood vessels. Recent studies have revealed the phenotypic and functional heterogeneity of bone marrow endothelial cells. This has facilitated the analysis of the vascular microenvironment in steady state and malignant hematopoiesis. In this review, we provide an overview of the bone marrow microenvironment, focusing on refined analyses of the marrow vascular compartment performed in mouse studies. We also discuss the emerging role of the vascular niche in “inflamm-aging” and clonal hematopoiesis, and how the endothelial microenvironment influences, supports and interacts with hematopoietic cells in acute myeloid leukemia and myelodysplastic syndromes, as exemplar states of malignant myelopoiesis. Finally, we provide an overview of strategies for modulating these bidirectional interactions to therapeutic effect in myeloid malignancies.DW and KB are supported by the Oglesby Charitable Trust. DW is additionally supported by a Blood Cancer United Kingdom Clinician Scientist Fellowship (number 15030). LM is supported by a grant from the National Blood Foundation (NBF). JS is supported by a Manchester Cancer Research Centre Studentship. ES is supported by research funding from The Christie Charitable Trust and The Academy of Medical Sciences. DD is funded by NBF, the European Hematology Association (EHA), and Fundação Amélia de Mello
Universal spectral behavior of potentials
The PT-symmetric Hamiltonian ( real)
exhibits a phase transition at . When , the
eigenvalues are all real, positive, discrete, and grow as increases.
However, when there are only a finite number of real eigenvalues.
As approaches -1 from above, the number of real eigenvalues
decreases to one, and this eigenvalue becomes infinite at . In
this paper it is shown that these qualitative spectral behaviors are generic
and that they are exhibited by the eigenvalues of the general class of
Hamiltonians ( real, n=1, 2, 3,
...). The complex classical behaviors of these Hamiltonians are also examined.Comment: 8 pages, 7 figure
An In Vitro Intact Globe Expansion Method for Evaluation of Cross-linking Treatments
Purpose. To measure the tissue mechanical response to elevated
intraocular pressure (IOP) using intact globe expansion
of rabbit eyes. This method examined rabbit kit (2–3 weeks
old) eyes as a model for weakened tissue and evaluated riboflavin/
UVA and glyceraldehyde cross-linking treatments.
Methods. The ocular shape of enucleated eyes was photographed
during a 24-hour period while a controlled IOP was
imposed (either low IOP 22 mm Hg or high IOP 85 mm
Hg). Untreated controls consisted of kit eyes tested at both
low- and high IOP and adult eyes tested at high IOP. Treated kit
eyes (dextran controls, riboflavin/UVA treatment of the cornea,
and glyceraldehyde treatment of the entire globe) were tested
at high IOP.
Results. Low IOP elicited negligible creep of the sclera and
very gradual creep of the cornea. In contrast, high IOP induced
up to an 8% strain in the sclera and a 15% strain in the cornea
of rabbit kit eyes. The expansion of adult eyes was less than
one third that of kit eyes at the same, high IOP. Riboflavin/UVA
treatment of corneas reduced expansion compared with that in
both dextran-treated and untreated control corneas. Glyceraldehyde
treatment prevented expansion of the cornea and
sclera.
Conclusions. The intact globe expansion method (GEM) imposes
a loading geometry comparable to in vivo conditions and
can quantify changes in mechanical stability as a function of
testing conditions (e.g., IOP, tissue maturation, and therapeutic
cross-linking) with small sample sizes and small variability.
Rabbit kit eyes provide a model of weak tissue suitable for
screening treatments that strengthen the cornea and sclera
Macrostate Data Clustering
We develop an effective nonhierarchical data clustering method using an
analogy to the dynamic coarse graining of a stochastic system. Analyzing the
eigensystem of an interitem transition matrix identifies fuzzy clusters
corresponding to the metastable macroscopic states (macrostates) of a diffusive
system. A "minimum uncertainty criterion" determines the linear transformation
from eigenvectors to cluster-defining window functions. Eigenspectrum gap and
cluster certainty conditions identify the proper number of clusters. The
physically motivated fuzzy representation and associated uncertainty analysis
distinguishes macrostate clustering from spectral partitioning methods.
Macrostate data clustering solves a variety of test cases that challenge other
methods.Comment: keywords: cluster analysis, clustering, pattern recognition, spectral
graph theory, dynamic eigenvectors, machine learning, macrostates,
classificatio
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