5,342 research outputs found
To what extent are the elementary schools of Newington, Connecticut, utilizing the resources of the community
Thesis (M.A.)--Boston University, 1947. This item was digitized by the Internet Archive
Sets of Priors Reflecting Prior-Data Conflict and Agreement
In Bayesian statistics, the choice of prior distribution is often debatable,
especially if prior knowledge is limited or data are scarce. In imprecise
probability, sets of priors are used to accurately model and reflect prior
knowledge. This has the advantage that prior-data conflict sensitivity can be
modelled: Ranges of posterior inferences should be larger when prior and data
are in conflict. We propose a new method for generating prior sets which, in
addition to prior-data conflict sensitivity, allows to reflect strong
prior-data agreement by decreased posterior imprecision.Comment: 12 pages, 6 figures, In: Paulo Joao Carvalho et al. (eds.), IPMU
2016: Proceedings of the 16th International Conference on Information
Processing and Management of Uncertainty in Knowledge-Based Systems,
Eindhoven, The Netherland
A method to extract pure Raman spectrum of epitaxial graphene on SiC
A method is proposed to extract pure Raman spectrum of epitaxial graphene on
SiC by using a Non-negative Matrix Factorization. It overcomes problems of
negative spectral intensity and poorly resolved spectra resulting from a simple
subtraction of a SiC background from the experimental data. We also show that
the method is similar to deconvolution, for spectra composed of multiple sub-
micrometer areas, with the advantage that no prior information on the impulse
response functions is needed. We have used this property to characterize the
Raman laser beam. The method capability in efficient data smoothing is also
demonstrated.Comment: 3 figures, regular pape
Balloon valvuloplasty of aortic valve stenosis in childhood: early and medium term results
Background: Isolated aortic valve stenosis in childhood is treated by balloon valvuloplasty. The role of independent risk factors for the outcome remains unclear. Material and methods: We analysed the early and medium term outcome of balloon valvuloplasty in isolated aortic valve stenosis in 44 pediatric patients with isolated, severe aortic valve stenosis at an age younger than 18 years, who received a primary balloon valvuloplasty during the last 5 years in our institution. We evaluated the type of aortic valve morphology, age, clinical status, and myocardial function at the time of the intervention as independent risk factor. Results: A significant early relief of the pressure gradient across the aortic valve (P < 0.001) after balloon valvuloplasty was found. This was independent of the aortic valve morphology. Two neonates with a highly stenotic tricuspid aortic valve and severely compromised haemodynamics died within the first 30 days after the intervention. During medium term follow up (mean 22.5 months) we observed a functional deterioration for the stenosis as well as for the insufficiency of the aortic valve. "Symptoms before intervention” is an independent risk factors (P < 0.001) for valvuloplasty failure. Patients at an "age at intervention ≤ 28 days” (P = 0.02) and patients with "reduced myocardial systolic function” (P = 0.01) had a shorter time to reintervention. Conclusions: The type of aortic valve morphology only has a weak predictive value for the outcome of balloon valvuloplasty during medium term follow up. Critical ill neonates with an impaired myocardial function are at a higher risk for valvuloplasty failur
SU(4) symmetry breaking revealed by magneto-optical spectroscopy in epitaxial graphene
Refined infrared magnetotransmission experiments have been performed in
magnetic fields B up to 35 T on a series of multilayer epitaxial graphene
samples. Following the main optical transition involving the n=0 Landau level
(LL), we observe a new absorption transition increasing in intensity with
magnetic fields B>26 T. Our analysis shows that this is a signature of the
breaking of the SU(4) symmetry of the n=0 LL. Using a quantitative model, we
show that the only symmetry-breaking scheme consistent with our experiments is
a charge density wave (CDW)
Probing terahertz surface plasmon waves in graphene structures
Epitaxial graphene mesas and ribbons are investigated using terahertz (THz)
nearfield microscopy to probe surface plasmon excitation and THz transmission
properties on the sub-wavelength scale. The THz near-field images show
variation of graphene properties on a scale smaller than the wavelength, and
excitation of THz surface waves occurring at graphene edges, similar to that
observed at metallic edges. The Fresnel reflection at the substrate SiC/air
interface is also found to be altered by the presence of graphene ribbon
arrays, leading to either reduced or enhanced transmission of the THz wave
depending on the wave polarization and the ribbon width.Comment: accepted for publication in Applied Physics Lette
The Role of Transport Agents in MoS2 Single Crystals
We report resistivity, thermoelectric power and thermal conductivity of MoS2
single crystals prepared by chemical vapour transport (CVT) method using I2,
Br2 and TeCl4 as transport agents. The material presents low-lying donor and
acceptor levels, which dominate the in-plane charge transport. Intercalates
into the Van der Waals gap strongly influence the inter-plane resistivity.
Thermoelectric power displays the characteristics of strong electron-phonon
interaction. Detailed theoretical model of thermal conductivity reveals the
presence of high number of defects in the MoS2 structure. We show that these
defects are inherent to CVT growth method, coming mostly from the transport
agent molecules inclusion as identified by Total Reflection X-ray Fluorescence
analysis (TXRF) and in-beam activation analysis (IBAA).Comment: 17 pages, 5 figure
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