274 research outputs found
Lie systems and integrability conditions for t-dependent frequency harmonic oscillators
Time-dependent frequency harmonic oscillators (TDFHO's) are studied through
the theory of Lie systems. We show that they are related to a certain kind of
equations in the Lie group SL(2,R). Some integrability conditions appear as
conditions to be able to transform such equations into simpler ones in a very
specific way. As a particular application of our results we find t-dependent
constants of the motion for certain one-dimensional TDFHO's. Our approach
provides an unifying framework which allows us to apply our developments to all
Lie systems associated with equations in SL(2,R) and to generalise our methods
to study any Lie system
Allogeneic bone marrow (BM) peripheral blood progenitor cells (PBPC) transplantations in two cases prepared with the use of total body irradiation (TBI)
The main aims for preparative regimens in BMT/PBPCT are malignant cell eradication and/or immunosupresion to facilitate engraftment. TBI is used in concert with cyclophospamide (Cy) to increase activity.In our Unit two TBI + Cy conditioned allotransplantations – (1) BMT and (2) PBPCT – have been performed. Patients – (1) 7 years and (2) 10 years old, males, suffering from: (1) ALL – second and (2) ALL – fourth remission, received transplant material from HLA identical siblings. Transplant preparative regimens consisted of TBI (Co-60 + electrons 6 and 9 MeV: 12–16 Gy. performed in Greatpoland Cancer Centre, Poznań) and Cy (200 mg/kg bw). Patients received routine decontamination for infection prevention. Heparine for VOD and Cyclosporine + MTX for GvHD prophylaxis. Treatment related toxicity was judged accordind to WHO scale, standard criteria were used for GvHD grading.Both patients were Hepatitis B virus positive, patient (2) was also HCV + before treatment. Hematological recovery was observed in both patient (1) 13 and (2) 10 days after transplantation. Toxicity in patient (1) was WHO-1 for the liver and WHO-1 for kidneys. There was no skin or mucosal toxicity. Patient (2) had WHO-2 GIT mucosa and WHO-3 liver toxicities on day +15. No skin toxicity was observed. On day +16 patient(2) rapidly developed signs of pulmonary complications further followed by CNS involvement. He required artificial ventilation. No aGvHD observed. Patient died on day +31. Patient (1) is alive and well +36 days after transplantation. aGvHD grade I (skin) was observed on day +25 after transplantation and responded well to glukokorticosteroid therapy (2mg/kg for 5 days).The post-transplant history of these two cases reflects on possible complications of BMT/PBPCT with TBI
Integrability of Lie systems through Riccati equations
Integrability conditions for Lie systems are related to reduction or
transformation processes. We here analyse a geometric method to construct
integrability conditions for Riccati equations following these approaches. This
approach provides us with a unified geometrical viewpoint that allows us to
analyse some previous works on the topic and explain new properties. Moreover,
this new approach can be straightforwardly generalised to describe
integrability conditions for any Lie system. Finally, we show the usefulness of
our treatment in order to study the problem of the linearisability of Riccati
equations.Comment: Corrected typo
Strategies to Maximize Science Data Availability for the GOES-R Series of Satellites
The Geostationary Operational Environmental Satellite-R Series (GOES-R) is the next generation of Untied States geostationary weather satellites. The GOES-R series significantly improves the detection and observation of environmental phenomena that directly affect public safety, protection of property and the economic health and prosperity of the United States and all countries within the western hemisphere. Given the real-time or ''now-casting'' nature of the GOES science gathering mission, any data outage or interruption can reduce warning times or scientific fidelity for critical weather data. GOES-R mission level requirements limit key performance product outages to a total of six hours per year to maximize science data availability. Lower level requirement only allow for 120 minutes of disruption between the spacecraft bus interface to the instruments. This requirement is met using both design features of the satellite and ground system, in addition to operational strategies
Measurement of inclusive charged current interactions on carbon in a few-GeV neutrino beam
The SciBooNE Collaboration reports a measurement of inclusive charged current
interactions of muon neutrinos on carbon with an average energy of 0.8 GeV
using the Fermilab Booster Neutrino Beam. We compare our measurement with two
neutrino interaction simulations: NEUT and NUANCE. The charged current
interaction rates (product of flux and cross section) are extracted by fitting
the muon kinematics, with a precision of 6-15% for the energy dependent and 3%
for the energy integrated analyses. We also extract CC inclusive interaction
cross sections from the observed rates, with a precision of 10-30% for the
energy dependent and 8% for the energy integrated analyses. This is the first
measurement of the CC inclusive cross section on carbon around 1 GeV. These
results can be used to convert previous SciBooNE cross section ratio
measurements to absolute cross section values.Comment: 21 pages, 16 figures. Accepted by Phys. Rev. D. Minor revisions to
match the accepted versio
Search for Charged Current Coherent Pion Production on Carbon in a Few-GeV Neutrino Beam
The SciBooNE Collaboration has performed a search for charged current
coherent pion production from muon neutrinos scattering on carbon, \nu_\mu
^{12}C \to \mu^- ^{12}C \pi^+, with two distinct data samples. No evidence for
coherent pion production is observed. We set 90% confidence level upper limits
on the cross section ratio of charged current coherent pion production to the
total charged current cross section at 0.67\times 10^{-2} at mean neutrino
energy 1.1 GeV and 1.36\times 10^{-2} at mean neutrino energy 2.2 GeV.Comment: 18 pages, 16 figures, Minor revisions to match version accepted for
publication in Physical Review
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Cannabinoids Inhibit Insulin Receptor Signaling in Pancreatic -Cells
Objective: Optimal glucose homeostasis requires exquisitely precise adaptation of the number of insulin-secreting -cells in the islets of Langerhans. Insulin itself positively regulates -cell proliferation in an autocrine manner through the insulin receptor (IR) signaling pathway. It is now coming to light that cannabinoid 1 receptor (CB1R) agonism/antagonism influences insulin action in insulin-sensitive tissues. However, the cells on which the CB1Rs are expressed and their function in islets have not been firmly established. We undertook the current study to investigate if intraislet endogenous cannabinoids (ECs) regulate -cell proliferation and if they influence insulin action. Research Design and Methods: We measured EC production in isolated human and mouse islets and -cell line in response to glucose and KCl. We evaluated human and mouse islets, several -cell lines, and CB1R-null (CB1R) mice for the presence of a fully functioning EC system. We investigated if ECs influence -cell physiology through regulating insulin action and demonstrated the therapeutic potential of manipulation of the EC system in diabetic (db/db) mice. Results: ECs are generated within -cells, which also express CB1Rs that are fully functioning when activated by ligands. Genetic and pharmacologic blockade of CB1R results in enhanced IR signaling through the insulin receptor substrate 2-AKT pathway in -cells and leads to increased -cell proliferation and mass. CB1R antagonism in db/db mice results in reduced blood glucose and increased -cell proliferation and mass, coupled with enhanced IR signaling in -cells. Furthermore, CB1R activation impedes insulin-stimulated IR autophosphorylation on -cells in a G-dependent manner. Conclusions: These findings provide direct evidence for a functional interaction between CB1R and IR signaling involved in the regulation of -cell proliferation and will serve as a basis for developing new therapeutic interventions to enhance -cell function and proliferation in diabetes
Inclusive Search for Anomalous Production of High-pT Like-Sign Lepton Pairs in Proton-Antiproton Collisions at sqrt{s}=1.8 TeV
We report on a search for anomalous production of events with at least two
charged, isolated, like-sign leptons with pT > 11 GeV/c using a 107 pb^-1
sample of 1.8 TeV ppbar collisions collected by the CDF detector. We define a
signal region containing low background from Standard Model processes. To avoid
bias, we fix the final cuts before examining the event yield in the signal
region using control regions to test the Monte Carlo predictions. We observe no
events in the signal region, consistent with an expectation of
0.63^(+0.84)_(-0.07) events. We present 95% confidence level limits on new
physics processes in both a signature-based context as well as within a
representative minimal supergravity (tanbeta = 3) model.Comment: 15 pages, 4 figures. Minor textual changes, cosmetic improvements to
figures and updated and expanded reference
Measurement of and Production in Collisions at = 1.96 TeV
The Standard Model predictions for and production are
tested using an integrated luminosity of 200 pb of \ppbar collision data
collected at the Collider Detector at Fermilab. The cross sections are measured
selecting leptonic decays of the and bosons, and photons with
transverse energy GeV that are well separated from leptons. The
production cross sections and kinematic distributions for the and
are compared to SM predictions.Comment: 7 pages, 4 figures, submitted to PR
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