4,545 research outputs found
W/Z boson production in muonic final states at the ATLAS experiment
W and Z boson production has been investigated by the ATLAS
Collaboration in proton-proton collisions at √s = 7 TeV. New preliminary precision measurements of the inclusive Dell-Yan cross sections based on the complete data
statistics collected in 2010, corresponding to a luminosity of about 35 pb−1, are presented, with particular emphasis on the muon decay channels. The accurate control on experimental systematic uncertainties, at the percent level, shows advanced understanding of the muon trigger and reconstruction achieved after the first year of data taking at the LHC. The measured W± and Z/γ∗ cross sections, and their ratios, are in agreement with next-to-next-to-leading-order (NNLO) QCD calculations and start to be sensitive to the choice of the parton distribution functions
Influence of the disorder on tracer dispersion in a flow channel
Tracer dispersion is studied experimentally in periodic or disordered arrays
of beads in a capillary tube. Dispersion is measured from light absorption
variations near the outlet following a steplike injection of dye at the inlet.
Visualizations using dye and pure glycerol are also performed in similar
geometries. Taylor dispersion is dominant both in an empty tube and for a
periodic array of beads: the dispersivity increases with the P\'eclet
number respectively as and and is larger by a factor of 8
in the second case. In a disordered packing of smaller beads (1/3 of the tube
diameter) geometrical dispersion associated to the disorder of the flow field
is dominant with a constant value of reached at high P\'eclet numbers.
The minimum dispersivity is slightly higher than in homogeneous nonconsolidated
packings of small grains, likely due heterogeneities resulting from wall
effects. In a disordered packing with the same beads as in the periodic
configuration, is up to 20 times lower than in the latter and varies as
with or (depending on the fluid viscosity).
A simple model accounting for this latter result is suggested.Comment: available online at
http://www.edpsciences.org/journal/index.cfm?edpsname=epjap&niv1=contents&niv2=archive
Nonlinear diffusion & thermo-electric coupling in a two-variable model of cardiac action potential
This work reports the results of the theoretical investigation of nonlinear
dynamics and spiral wave breakup in a generalized two-variable model of cardiac
action potential accounting for thermo-electric coupling and diffusion
nonlinearities. As customary in excitable media, the common Q10 and Moore
factors are used to describe thermo-electric feedback in a 10-degrees range.
Motivated by the porous nature of the cardiac tissue, in this study we also
propose a nonlinear Fickian flux formulated by Taylor expanding the voltage
dependent diffusion coefficient up to quadratic terms. A fine tuning of the
diffusive parameters is performed a priori to match the conduction velocity of
the equivalent cable model. The resulting combined effects are then studied by
numerically simulating different stimulation protocols on a one-dimensional
cable. Model features are compared in terms of action potential morphology,
restitution curves, frequency spectra and spatio-temporal phase differences.
Two-dimensional long-run simulations are finally performed to characterize
spiral breakup during sustained fibrillation at different thermal states.
Temperature and nonlinear diffusion effects are found to impact the
repolarization phase of the action potential wave with non-monotone patterns
and to increase the propensity of arrhythmogenesis
A feasibility study for a circular approach in oil refining: Metals recovery from hydrodesulphurization catalysts
The paper deals with a profitability analysis developed for a plant that recycles spent hydrodesulphurization (HDS) catalysts. Such catalysts contain molybdenum (Mo), nickel (Ni), and vanadium (V), supported by an alumina (Al2O3) carrier. The recycling process is based on a double thermal pre-treatment stage, followed by a series of hydrometallurgical steps that allow recovering Mo and V and a Ni concentrate that need further refining for separation and recovery of the metals. The economic analysis is based on the discounted cash flow method, and the baseline case analyses show that the net present value (NPV) is 14,877 thousand EUR. The selling price of vanadium pentoxide strongly influences the results. Alternative scenarios are also studied to strengthen the results obtained, considering the sensitivity, scenario and risk analyses. Profitability is confirmed in 87% of the considered scenarios, and in about 81.5%, the NPV of the baseline scenario is achieved. Circular economy models can be realized if products are recovered and if there are technologies that can recover metals. This study confirms that an example of a circular economy is met from the proposed viability analysis, and the economic benefits can be significant
Strong extinction of a far-field laser beam by a single quantum dot
Through the utilization of index-matched GaAs immersion lens techniques we
demonstrate a record extinction (12%) of a far-field focused laser by a single
InAs/GaAs quantum dot. This contrast level enables us to report for the first
time resonant laser transmission spectroscopy on a single InAs/GaAs quantum dot
without the need for phase-sensitive lock-in detection
Rhythmic TMS as a Feasible Tool to Uncover the Oscillatory Signatures of Audiovisual Integration
Multisensory integration is quintessential to adaptive behavior, with clinical populations showing significant impairments in this domain, most notably hallucinatory reports. Interestingly, altered cross-modal interactions have also been reported in healthy individuals when engaged in tasks such as the Sound-Induced Flash-Illusion (SIFI). The temporal dynamics of the SIFI have been recently tied to the speed of occipital alpha rhythms (IAF), with faster oscillations entailing reduced temporal windows within which the illusion is experienced. In this regard, entrainment-based protocols have not yet implemented rhythmic transcranial magnetic stimulation (rhTMS) to causally test for this relationship. It thus remains to be evaluated whether rhTMS-induced acoustic and somatosensory sensations may not specifically interfere with the illusion. Here, we addressed this issue by asking 27 volunteers to perform a SIFI paradigm under different Sham and active rhTMS protocols, delivered over the occipital pole at the IAF. Although TMS has been proven to act upon brain tissues excitability, results show that the SIFI occurred for both Sham and active rhTMS, with the illusory rate not being significantly different between baseline and stimulation conditions. This aligns with the discrete sampling hypothesis, for which alpha amplitude modulation, known to reflect changes in cortical excitability, should not account for changes in the illusory rate. Moreover, these findings highlight the viability of rhTMS-based interventions as a means to probe the neuroelectric signatures of illusory and hallucinatory audiovisual experiences, in healthy and neuropsychiatric populations
On attributes of a Rotating Neutron star with a Hyperon core
We study the effect of rotation on global properties of neutron star with a
hyperon core in an effective chiral model with varying nucleon effective mass
within a mean field approach. The resulting gross properties of the rotating
compact star sequences are then compared and analyzed with other theoretical
predictions and observations from neutron stars. The maximum mass of the
compact star predicted by the model lies in the range at
Kepler frequency , which is consistant with recent observation of
high mass stars thereby reflecting the sensitivity of the underlying nucleon
effective mass in the dense matter EoS. We also discuss the implications of the
experimental constraints from the flow data from heavy-ion collisions on the
global properties of the rotating neutron stars.Comment: 11 Pages, 10 Figures and 2 Table
The Role of Alpha Oscillations among the Main Neuropsychiatric Disorders in the Adult and Developing Human Brain: Evidence from the Last 10 Years of Research
Alpha oscillations (7–13 Hz) are the dominant rhythm in both the resting and active brain.
Accordingly, translational research has provided evidence for the involvement of aberrant alpha activ-
ity in the onset of symptomatological features underlying syndromes such as autism, schizophrenia,
major depression, and Attention Deficit and Hyperactivity Disorder (ADHD). However, findings on
the matter are difficult to reconcile due to the variety of paradigms, analyses, and clinical phenotypes
at play, not to mention recent technical and methodological advances in this domain. Herein, we seek
to address this issue by reviewing the literature gathered on this topic over the last ten years. For each
neuropsychiatric disorder, a dedicated section will be provided, containing a concise account of the
current models proposing characteristic alterations of alpha rhythms as a core mechanism to trigger
the associated symptomatology, as well as a summary of the most relevant studies and scientific con-
tributions issued throughout the last decade. We conclude with some advice and recommendations
that might improve future inquiries within this field
Accuracy of EEG Biomarkers in the Detection of Clinical Outcome in Disorders of Consciousness after Severe Acquired Brain Injury: Preliminary Results of a Pilot Study Using a Machine Learning Approach
Accurate outcome detection in neuro-rehabilitative settings is crucial for appropriate long-term rehabilitative decisions in patients with disorders of consciousness (DoC). EEG measures derived from high-density EEG can provide helpful information regarding diagnosis and recovery in DoC patients. However, the accuracy rate of EEG biomarkers to predict the clinical outcome in DoC patients is largely unknown. This study investigated the accuracy of psychophysiological biomarkers based on clinical EEG in predicting clinical outcomes in DoC patients. To this aim, we extracted a set of EEG biomarkers in 33 DoC patients with traumatic and nontraumatic etiologies and estimated their accuracy to discriminate patients' etiologies and predict clinical outcomes 6 months after the injury. Machine learning reached an accuracy of 83.3% (sensitivity = 92.3%, specificity = 60%) with EEG-based functional connectivity predicting clinical outcome in nontraumatic patients. Furthermore, the combination of functional connectivity and dominant frequency in EEG activity best predicted clinical outcomes in traumatic patients with an accuracy of 80% (sensitivity = 85.7%, specificity = 71.4%). These results highlight the importance of functional connectivity in predicting recovery in DoC patients. Moreover, this study shows the high translational value of EEG biomarkers both in terms of feasibility and accuracy for the assessment of DoC
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