2,840 research outputs found
Axioms for consensus functions on the n-cube
An elementary general result is proved that allows for simple
characterizations of well-known location/consensus functions (median, mean and
center) on the n-cube. In addition, alternate new characterizations are given
for the median and anti-median functions on the n-cube.Comment: 12 page
Broad-area electron-beam-assisted etching of silicon in sulfur hexafluoride
Includes bibliographical references (page 1583).Silicon etching rates up to 250 Ă
/min have been observed in an electron-beam-generated He plus SF6 plasma. The etch rate was found to increase linearly with electron beam current density and to be practically independent of the electron acceleration voltage in the range investigated (170-260 V). Profiles of the resulting features show that etching is anisotropic with a vertical-to-horizontal ratio of 2.5 to 3
Laser-driven direct synthesis of carbon nanodots and application as sensitizers for visible-light photocatalysis
We present the first successful synthesis of monodisperse carbon nanodots (CNDs) with tunable photoluminescence (PL) carried out by laser pyrolysis of two common volatile organic precursors such as toluene and pyridine. Remarkably, the initial chemical composition of the precursor determines the formation of undoped or N-doped CNDs and their corresponding absorption response in the visible range (expanded for the latter). We demonstrate the control and versatility of this synthesis method to tune the final outcome and its potential to explore a great number of potential solvent candidates. Furthermore, we have successfully exploited these CNDs (both undoped and N-doped) as effective sensitizers of TiO2 nanoparticles in the visible-light driven photo-degradation of a cationic dye selected as model organic pollutant
Pumping Metallic Nanoparticles with Spatial Precision within Magnetic Mesoporous Platforms: 3D Characterization and Catalytic Application
The present work shows an efficient strategy to assemble two types of functional nanoparticles onto mesoporous MCM-41 silica nanospheres with a high degree of spatial precision. In a first stage, magnetite nanoparticles are synthesized with a size larger than the support pores and grafted covalently through a peptide-like bonding onto their external surface. This endowed the silica nanoparticles with a strong superparamagnetic response, while preserving the highly ordered interior space for the encapsulation of other functional guest species. Second, we report the finely controlled pumping of preformed Pt nanoparticles (1.5 nm) within the channels of the magnetic MCM-41 nanospheres to confer an additional catalytic functionality to the multiassembled nanoplatform. The penetration depth of the metallic nanoparticles can be explained as a result of the interplay between the particle-wall electrostatic attraction and the repulsive forces between neighboring Pt nanoparticles. A detailed transmission electron microscopy and a 3D high-resolution high-angle annular dark-field detector electron tomography study were carried out to characterize the material and to explain the assembly mechanism. Finally, the performance of these multifunctional nanohybrids as magnetically recoverable catalysts has been evaluated in the selective hydrogenation of p-nitrophenol, a well-known pollutant and intermediate in multiple industrial processes
The Sound of Topology in the AdS/CFT Correspondence
Using the gauge/gravity correspondence, we study the properties of 2-point
correlation functions of finite-temperature strongly coupled gauge field
theories, defined on a curved space of general spatial topology with a dual
black hole description. We derive approximate asymptotic expressions for the
correlation functions and their poles, supported by exact numerical
calculations, and study their dependence on the dimension of spacetime and the
spatial topology. The asymptotic structure of the correlation functions depends
on the relation between the spatial curvature and the temperature, and is
noticeable when they are of the same order. In the case of a hyperbolic
topology, a specific temperature is identified for which exact analytical
solutions exist for all types of perturbations. The asymptotic structure of the
correlation functions poles is found to behave in a non-smooth manner when
approaching this temperature.Comment: 65 pages, LaTeX, 21 figures, 1 table; fixed a small error in
subsection 3.
Experiencia clĂnica del tratamiento con onabotulinumtoxin A en pacientes con migraña refractaria
To analyse our experience in the treatment of refractory chronic migraine,
episodic frequent refractory migraine (>= 10 days/month), with onabotulinumtoxin
A (OnabotA). PATIENTS AND METHODS. Retrospective analysis of patients with
refractory migraine who underwent, at least two sessions of OnabotA pericranial
injections following the PREEMPT protocol between 2008 and 2012. The efficacy of
OnabotA was evaluated comparing the basal situation with 12-16 weeks after the
second session. We analysed the subjective improvement of the patients, number of
days with headache, preventive and abortive drugs consumption, and adverse
effects. RESULTS. Forty-one patients (37 women, 4 male) were identified. 65.8%
patients experienced subjective improvement after OnabotA treatment. 36.58%
responded (reduction of > 50% in headache days). Differences between days with
headache before the first session (24.5 +/- 7.3), and 12-16 weeks after the
second session (17.4 +/- 11.6), as well as the differences between the number of
abortive drugs taken before the first session (26.8 +/- 23.1) and 12-16 weeks
after the second session (16.7 +/- 19.3), were statistically significant (p <
0.001). Subgroups analysis showed that all differences were significant, except
for the reduction of the number of days with headache in patients with episodic
frequent refractory migraine. CONCLUSION. Our work shows that treatment with
OnabotA is safe and useful in patients with episodic and chronic refractory
migraine, including those patients with medication overuse headache
- âŠ