1,936 research outputs found
Tunable subpicosecond electron bunch train generation using a transverse-to-longitudinal phase space exchange technique
We report on the experimental generation of a train of subpicosecond electron
bunches. The bunch train generation is accomplished using a beamline capable of
exchanging the coordinates between the horizontal and longitudinal degrees of
freedom. An initial beam consisting of a set of horizontally-separated beamlets
is converted into a train of bunches temporally separated with tunable bunch
duration and separation. The experiment reported in this Letter unambiguously
demonstrates the conversion process and its versatility.Comment: 4 pages, 5 figures, 1 table; accepted for publication in PR
Upgrades of beam diagnostics in support of emittance-exchange experiments at the Fermilab A0 photoinjector
The possibility of using electron beam phase space manipulations to support a
free-electron laser accelerator design optimization has motivated our research.
An on-going program demonstrating the exchange of transverse horizontal and
longitudinal emittances at the Fermilab A0 photoinjector has benefited recently
from the upgrade of several of the key diagnostics stations. Accurate
measurements of these properties upstream and downstream of the exchanger
beamline are needed. Improvements in the screen resolution term and reduced
impact of the optical system's depth-of-focus by using YAG:Ce single crystals
normal to the beam direction will be described. The requirement to measure
small energy spreads (<10 keV) in the spectrometer and the exchange process
which resulted in bunch lengths less than 500 fs led to other diagnostics
performance adjustments and upgrades as well. A longitudinal to transverse
exchange example is also reported.Comment: 16 p
First observation of the exchange of transverse and longitudinal emittances
An experimental program to demonstrate a novel phase space manipulation in
which the horizontal and longitudinal emittances of a particle beam are
exchanged has been completed at the Fermilab A0 Photoinjector. A new beamline,
consisting of a TM110 deflecting mode cavity flanked by two horizontally
dispersive doglegs has been installed. We report on the first direct
observation of transverse and longitudinal emittance exchange
Tako-tsubo cardiomyopathy after administration of ergometrine following elective caesarean delivery: a case report
<p>Abstract</p> <p>Introduction</p> <p>Tako-tsubo cardiomyopathy (stress-induced cardiomyopathy or transient left ventricular ballooning) is characterized by clinical suspicion of an acute myocardial infarction with transient apical or midventricular dyskinesia of the left ventricle without significant coronary stenosis on angiography. The etiology of this disease remains obscure. One of the possible causes is myocardial ischemia induced by coronary vasospasm due to sympathetic activation. It has been hypothesized that the application of ergometrine could induce tako-tsubo cardiomyopathy.</p> <p>Case presentation</p> <p>We report the case of a 28-year-old Turkish woman who developed tako-tsubo cardiomyopathy after administration of ergometrine for release of placenta and prevention of bleeding during the post-partum phase in the course of an elective caesarean delivery. Tako-tsubo cardiomyopathy was diagnosed by echocardiography and urgent cardiac magnetic resonance imaging. A coronary angiography was not performed because of the absence of myocardial necrosis or ischemia and signs of myocarditis on cardiac magnetic resonance imaging.</p> <p>Conclusion</p> <p>This life-threatening disease should be excluded in the differential diagnosis by comparing the symptoms with those of typical heart failure, particularly after use of ergometrine.</p
Novel Helmholtz-based photoacoustic sensor for trace gas detection at ppm level using GaInAsSb/GaAlAsSb DFB lasers
QUESADA, ELENA E HIJA [Material gráfico]
Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201
Joint ancestry and association test indicate two distinct pathogenic pathways involved in classical dengue fever and dengue shock syndrome
Ethnic diversity has been long considered as one of the factors explaining why the severe forms of dengue are more prevalent in Southeast Asia than anywhere else. Here we take advantage of the admixed profile of Southeast Asians to perform coupled association-admixture analyses in Thai cohorts. For dengue shock syndrome (DSS), the significant haplotypes are located in genes coding for phospholipase C members (PLCB4 added to previously reported PLCE1), related to inflammation of blood vessels. For dengue fever (DF), we found evidence of significant association with CHST10, AHRR, PPP2R5E and GRIP1 genes, which participate in the xenobiotic metabolism signaling pathway. We conducted functional analyses for PPP2R5E, revealing by immunofluorescence imaging that the coded protein co-localizes with both DENV1 and DENV2 NS5 proteins. Interestingly, only DENV2-NS5 migrated to the nucleus, and a deletion of the predicted top-linking motif in NS5 abolished the nuclear transfer. These observations support the existence of differences between serotypes in their cellular dynamics, which may contribute to differential infection outcome risk. The contribution of the identified genes to the genetic risk render Southeast and Northeast Asian populations more susceptible to both phenotypes, while African populations are best protected against DSS and intermediately protected against DF, and Europeans the best protected against DF but the most susceptible against DSS.The research leading to these results has received funding from the European Commission Seventh Framework Programme [FP7/2007-2013] for the DENFREE project under Grant Agreement no. 282378. MO has a PhD grant from FCT (The Portuguese Foundation for Science and Technology - SFRH/BD/95626/2013). I3S is financed by FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Competitiveness and Internationalization Operational Programme (POCI), Portugal 2020, and by Portuguese funds through FCT/Ministério da Ciência, Tecnologia e Inovação in the framework of the project "Institute for Research and Innovation in Health Sciences" (POCI-01-0145-FEDER-007274). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
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A copper 3.9 GHz TM110 cavity for emittance exchange
An experiment is being developed at the FNAL Photoinjector Lab to demonstrate the exchange of longitudinal emittance with a transverse horizontal emittance. The longitudinal electric field of a TM{sub 110} cavity vanishes on axis and increases linearly with transverse displacement. This 'shearing' electric field is pivotal to the exchange. The design of this TM{sub 110} cavity is a variant of the Fermilab 3.9 GHz superconducting deflecting mode cavity; however, the cavity was constructed of OFHC copper. The authors report on the construction, field flatness, polarization and high power testing of a TM{sub 110} cavity
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Capture cavity II results at FNAL
As part of the research and development towards the International Linear Collider (ILC), several test facilities have been developed at Fermilab. This paper presents the latest Low Level RF (LLRF) results obtained with Capture Cavity II (CCII) at the ILC Test Accelerator (ILCTA) test facility. The main focus will be on controls and RF operations using the SIMCON based LLRF system developed in DESY [1]. Details about hardware upgrades and future work will be discussed
Na Activation Level Measurements of Fused Silica Rods in the LHC Target Absorber for Neutrals (TAN) Compared to FLUKA Simulations
The Target Absorbers for Neutrals (TANs) are located in a high-intensity
radiation environment inside the tunnel of the Large Hadron Collider (LHC).
TANs are positioned about m downstream from the beam interaction points.
Seven cm long fused silica rods with different dopant specifications were
irradiated in the TAN by the Beam RAte of Neutrals (BRAN) detector group during
+ data taking from 2016 to 2018 at the LHC. The peak dose delivered to
the fused silica rods was MGy. We report measurements of the Na
activation of the fused silica rods carried out at the University of Illinois
at Urbana-Champaign and Argonne National Laboratory. At the end of the
irradiation campaign, the maximum Na activity observed was
kBq corresponding to a density, , of Na nuclei. FLUKA Monte Carlo simulations have been performed
by the CERN FLUKA team to estimate Na activities for the irradiated BRAN
rod samples. The simulations reproduce the Na activity profile measured
along the rods, with a 35% underestimation of the experimental measurement
results.Comment: 11 pages, 14 figures, to be submitted to PRA
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