966 research outputs found
Model based learning for accelerated, limited-view 3D photoacoustic tomography
Recent advances in deep learning for tomographic reconstructions have shown
great potential to create accurate and high quality images with a considerable
speed-up. In this work we present a deep neural network that is specifically
designed to provide high resolution 3D images from restricted photoacoustic
measurements. The network is designed to represent an iterative scheme and
incorporates gradient information of the data fit to compensate for limited
view artefacts. Due to the high complexity of the photoacoustic forward
operator, we separate training and computation of the gradient information. A
suitable prior for the desired image structures is learned as part of the
training. The resulting network is trained and tested on a set of segmented
vessels from lung CT scans and then applied to in-vivo photoacoustic
measurement data
Introduction to a Quantum Theory over a Galois Field
We consider a quantum theory based on a Galois field. In this approach
infinities cannot exist, the cosmological constant problem does not arise, and
one irreducible representation (IR) of the symmetry algebra splits into
independent IRs describing a particle an its antiparticle only in the
approximation when de Sitter energies are much less than the characteristic of
the field. As a consequence, the very notions of particles and antiparticles
are only approximate and such additive quantum numbers as the electric, baryon
and lepton charges are conserved only in this approximation. There can be no
neutral elementary particles and the spin-statistics theorem can be treated
simply as a requirement that standard quantum theory should be based on complex
numbers.Comment: 43 pages, Latex, 1 figur
Expression Analysis of Fibronectin Type III Domain-Containing (FNDC) Genes in Inflammatory Bowel Disease and Colorectal Cancer
Background. Fibronectin type III domain-containing (FNDC) proteins fulfill manifold functions in tissue development and regulation of cellular metabolism. FNDC4 was described as anti-inflammatory factor, upregulated in inflammatory bowel disease (IBD). FNDC signaling includes direct cell-cell interaction as well as release of bioactive peptides, like shown for FNDC4 or FNDC5. The G-protein-coupled receptor 116 (GPR116) was found as a putative FNDC4 receptor. We here aim to comprehensively analyze the mRNA expression of FNDC1, FNDC3A, FNDC3B, FNDC4, FNDC5, and GPR116 in nonaffected and affected mucosal samples of patients with IBD or colorectal cancer (CRC). Methods. Mucosa samples were obtained from 30 patients undergoing diagnostic colonoscopy or from surgical resection of IBD or CRC. Gene expression was determined by quantitative real-time PCR. In addition, FNDC expression data from publicly available Gene Expression Omnibus (GEO) data sets (GDS4296, GDS4515, and GDS5232) were analyzed. Results. Basal mucosal expression revealed higher expression of FNDC3A and FNDC5 in the ileum compared to colonic segments. FNDC1 and FNDC4 were significantly upregulated in IBD. None of the investigated FNDCs was differentially expressed in CRC, just FNDC3A trended to be upregulated. The GEO data set analysis revealed significantly downregulated FNDC4 and upregulated GPR116 in microsatellite unstable (MSI) CRCs. The expression of FNDCs and GPR116 was independent of age and sex. Conclusions. FNDC1 and FNDC4 may play a relevant role in the pathobiology of IBD, but none of the investigated FNDCs is regulated in CRC. GPR116 may be upregulated in advanced or MSI CRC. Further studies should validate the altered FNDC expression results on protein levels and examine the corresponding functional consequences
production and Cronin effect from p+p, d+Au and Au+Au collisions at GeV from the PHENIX experiment
We present results on identified particle production in p+p, d+Au and Au+Au
collisions at GeV at mid-rapidity measured by the PHENIX
experiment. The centrality and flavor dependence of the Cronin effect in d+Au
collisions is measured. The Cronin effect for the protons in d+Au is larger
than that for the pions, but not large enough to account for the ``anomalous''
proton to pion ratio in central Au+Au collisions.Comment: 5 pages, 3 figures, contribution to the proceedings of the 17th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions
(Quark Matter 2004
On discrete integrable equations with convex variational principles
We investigate the variational structure of discrete Laplace-type equations
that are motivated by discrete integrable quad-equations. In particular, we
explain why the reality conditions we consider should be all that are
reasonable, and we derive sufficient conditions (that are often necessary) on
the labeling of the edges under which the corresponding generalized discrete
action functional is convex. Convexity is an essential tool to discuss
existence and uniqueness of solutions to Dirichlet boundary value problems.
Furthermore, we study which combinatorial data allow convex action functionals
of discrete Laplace-type equations that are actually induced by discrete
integrable quad-equations, and we present how the equations and functionals
corresponding to (Q3) are related to circle patterns.Comment: 39 pages, 8 figures. Revision of the whole manuscript, reorder of
sections. Major changes due to additional reality conditions for (Q3) and
(Q4): new Section 2.3; Theorem 1 and Sections 3.5, 3.6, 3.7 update
Letter from Felix Adler, New York, New York, to George Herbert Palmer : autograph manuscript signed, between 1877 and 1933
Letterhead: The Society for Ethical Culture of New York, Society House, 48 East 58th Street. Accompanied by pamphlet: Ethical culture for children : outlines of twenty-five simple lessons / by M.R. Kerr. (13 pages)https://repository.wellesley.edu/autographletters/1015/thumbnail.jp
Particle-Like Solutions of the Einstein-Dirac Equations
The coupled Einstein-Dirac equations for a static, spherically symmetric
system of two fermions in a singlet spinor state are derived. Using numerical
methods, we construct an infinite number of soliton-like solutions of these
equations. The stability of the solutions is analyzed. For weak coupling (i.e.,
small rest mass of the fermions), all the solutions are linearly stable (with
respect to spherically symmetric perturbations), whereas for stronger coupling,
both stable and unstable solutions exist. For the physical interpretation, we
discuss how the energy of the fermions and the (ADM) mass behave as functions
of the rest mass of the fermions. Although gravitation is not renormalizable,
our solutions of the Einstein-Dirac equations are regular and well-behaved even
for strong coupling.Comment: 31 pages, LaTeX, 21 PostScript figures, some references adde
Safety of transanal ileal pouch-anal anastomosis for ulcerative colitis: a retrospective observational cohort study
Background: Colectomy with transanal ileal pouch-anal anastomosis (taIPAA) is a surgical technique that can be used to treat benign colorectal disease. Ulcerative colitis is the most frequent inflammatory bowel disease (IBD) and although pharmacological therapy has improved, colectomy rates reach up to 15%. The objective of this study was to determine anastomotic leakage rates and treatment after taIPAA as well as short- and long-term pouch function.
Methods: We conducted a retrospective analysis of a prospective database of all patients undergoing taIPAA at an academic tertiary referral center in Germany, between 01/03/2015 and 31/08/2019. Patients with indications other than ulcerative colitis or with adjuvant chemotherapy following colectomy for colorectal carcinoma were excluded for short- and long-term follow up due to diverging postoperative care yet considered for evaluation of anastomotic leakage.
Results: A total of 22 patients undergoing taIPAA during the study time-window were included in analysis. Median age at the time of surgery was 32 +/- 12.5 (14-54) years. Two patients developed an anastomotic leakage at 11 days (early anastomotic leakage) and 9 months (late anastomotic leakage) after surgery, respectively. In both patients, pouches could be preserved with a multimodal approach. Twenty patients out of 22 met the inclusion criteria for short and long term follow-up. Data on short-term pouch function could be obtained in 14 patients and showed satisfactory pouch function with only four patients reporting intermittent incontinence at a median stool frequency of 9-10 times per day. In the long-term we observed an inflammation or "pouchitis" in 11 patients and a pouch failure in one patient.
Conclusion: Postoperative complication rates in patients with benign colorectal disease remain an area of concern for surgical patient safety. In this pilot study on 22 selected patients, taIPAA was associated with two patients developing anastomotic leakage. Future large-scale validation studies are required to determine the safety and feasibility of taIPAA in patients with ulcerative colitis
Why Does Disaster Recovery Work Influence Mental Health?: Pathways through Physical Health and Household Income
Disaster recovery work increases risk for mental health problems, yet the mechanisms underlying this association are unclear. We explored links from recovery work to posttraumatic stress (PTS), major depression (MD) and generalized anxiety disorder (GAD) symptoms through physical health symptoms and household income in the aftermath of the Deepwater Horizon oil spill. As part of the NIEHS GuLF STUDY, participants (N = 10,141) reported on cleanup work activities, spill-related physical health symptoms, and household income at baseline, and mental health symptoms an average of 14.69 weeks (SD = 16.79) thereafter. Cleanup work participation was associated with higher physical health symptoms, which in turn were associated with higher PTS, MD, and GAD symptoms. Similar pattern of results were found in models including workers only and investigating the influence of longer work duration and higher work-related oil exposure on mental health symptoms. In addition, longer worker duration and higher work-related oil exposure were associated with higher household income, which in turn was associated with lower MD and GAD symptoms. These findings suggest that physical health symptoms contribute to workers’ risk for mental health symptoms, while higher household income, potentially from more extensive work, might mitigate risk
Anatomy of Prominent B and K Decays and Signatures of CP-Violating New Physics in the Electroweak Penguin Sector
The recent observation of B_d -> pi^0 pi^0 at the B factories with a
surprisingly large branching ratio represents a challenge for theory, and
complements the amazingly small B_d -> pi^+ pi^- rate. We point out that all
puzzling B -> pi pi features can be accommodated in the Standard Model (SM)
through non-factorizable hadronic interference effects, extract the relevant
parameters, and predict the CP asymmetries of B_d -> pi^0 pi^0. Using then
SU(3) flavour-symmetry and plausible dynamical assumptions, we fix the hadronic
B -> pi K parameters through their B -> pi pi counterparts, and determine the
CKM angle gamma, with a result in remarkable accordance with the usual fits for
the unitarity triangle. We may then analyse the B -> pi K system in the SM,
where we find agreement with the experimental picture, with the exception of
those observables that are significantly affected by electroweak (EW) penguins,
thereby suggesting new physics (NP) in this sector. Indeed, a moderate
enhancement of these topologies and a large CP-violating NP phase allow us to
describe any currently observed feature of the B -> pi K modes, and to predict
the CP-violating B_d -> pi^0 K_S observables. If we then restrict ourselves to
a specific scenario where NP enters only through Z^0 penguins, we obtain a link
to rare K and B decays, where the most spectacular NP effects are an
enhancement of the K_L -> pi^0 nu nu_bar rate by one order of magnitude with
BR(K_L -> pi^0 nu nu_bar) ~ 4 BR(K^+ -> pi^+ nu nu_bar), BR(K_L -> pi^0 e^+
e^-) = O(10^-10), (sin 2beta)_{pi nu nu_bar} < 0, and a large forward-backward
CP asymmetry in B_d -> K^* mu^+ mu^-. We address also epsilon'/epsilon and
other prominent decays, including B -> phi K and B -> J/psi K modes.Comment: 78 pages, 12 figures, LaTe
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