Search results for "maximum"
showing 10 items of 753 documents
Existence of positive solutions for nonlinear Dirichlet problems with gradient dependence and arbitrary growth
2018
We consider a nonlinear elliptic problem driven by the Dirichlet $p$-Laplacian and a reaction term which depends also on the gradient (convection). No growth condition is imposed on the reaction term $f(z, \cdot,y)$. Using topological tools and the asymptotic analysis of a family of perturbed problems, we prove the existence of a positive smooth solution.
High Bias Voltage CZT Detectors for High-flux Measurements
2017
In this work, we present the performance of new travelling heater method (THM) grown CZT detectors, recently developed at IMEM-CNR Parma, Italy. Thick planar detectors (3 mm thick) with gold electroless contacts on CZT crystals grown by Redlen Technologies (Victoria BC, Canada) were realized, with a planar cathode covering the detector surface (4.1 x 4.1 mm(2)) and a central anode (2 x 2 mm(2)) surrounded by a guard ring electrode. The detectors, characterized by low leakage currents at room temperature (4.7 nA/cm(2) at 1000 V/cm), allow good room temperature operation even at high bias voltages (> 7000 V/cm). At low rates, the detectors exhibit an energy resolution around 4 % FWIEM at 59.5…
Microscale X-ray mapping of CZT arrays: Spatial dependence of amplitude, shape and multiplicity of detector pulses
2018
In this work, we present the results of a microscale X-ray mapping of a 2 mm thick CZT pixel detector, with pixel pitches of 500 μm and 250 μm, using collimated synchrotron X-ray sources at the Diamond Light source (U. K.). The detector is dc coupled to a fast and low noise ASIC (PIXIE ASIC), characterized only by the preamplifier stage. A custom 16-channel digital readout electronics was used, able to perform online fast pulse shape and height analysis (PSHA), with low dead time and reasonable energy resolution at both low and high fluxes. The detector allows high bias voltage operation (> 5000 V/cm) and good energy resolution at room temperature (5.3 %, 2.3 % and 2.1 % FWHM at 22.1, 59…
KOSMOS 2017 Peru Side Experiment: nutrients, phytoplankton abundances, enzyme rates, photophysiology
2022
This data was collected during an short-term incubation experiment in March 2017 that investigated the response of a surface plankton community to upwelling. This experiment was carried in the framework of the SFB754-funded KOSMOS mesocosm study that took place in La Punta, Callao, Peru between February-April 2017. A total of six different treatments were used to disentangle chemical and biological characteristics of deep water that influence surface plankton blooms: 2 different deep water sources with different nutrient concentrations; 3 treatments to distinguish the effects of inorganic nutrients, organic nutrients and deep water microbial populations. Measured variables include inorganic…
Singular (p, q)-equations with superlinear reaction and concave boundary condition
2020
We consider a parametric nonlinear elliptic problem driven by the sum of a p-Laplacian and of a q-Laplacian (a (Formula presented.) -equation) with a singular and (Formula presented.) -superlinear reaction and a Robin boundary condition with (Formula presented.) -sublinear boundary term (Formula presented.). So, the problem has the combined effects of singular, concave and convex terms. We look for positive solutions and prove a bifurcation-type theorem describing the changes in the set of positive solutions as the parameter varies.
Spatial spillovers in France: a study on individual count data at the city level
2007
Our study aims to measure the effects of spatial R&D spillovers on firms' patent production at the city level. We use an original method to estimate the spatial dimension of spillovers using count data. The method, based on a generalized cross entropy approach, allows us to test spatial auto-correlation. The main result is that when there are local spillovers, their impact on knowledge production is different according to the geographical area and the sector.
SNP and SML estimation of univariate and bivariate binary–choice models
2008
We discuss the semi-nonparametric approach of Gallant and Nychka (1987, Econometrica 55: 363–390), the semiparametric maximum likelihood approach of Klein and Spady (1993, Econometrica 61: 387–421), and a set of new Stata commands for semiparametric estimation of three binary-choice models. The first is a univariate model, while the second and the third are bivariate models without and with sample selection, respectively. The proposed estimators are root-n consistent and asymptotically normal for the model parameters of interest under weak assumptions on the distribution of the underlying error terms. Our Monte Carlo simulations suggest that the efficiency losses of the semi-nonparametric a…
The Radó–Kneser–Choquet theorem for $p$-harmonic mappings between Riemannian surfaces
2020
In the planar setting the Rad\'o-Kneser-Choquet theorem states that a harmonic map from the unit disk onto a Jordan domain bounded by a convex curve is a diffeomorphism provided that the boundary mapping is a homeomorphism. We prove the injectivity criterion of Rad\'o-Kneser-Choquet for $p$-harmonic mappings between Riemannian surfaces. In our proof of the injecticity criterion we approximate the $p$-harmonic map with auxiliary mappings that solve uniformly elliptic systems. We prove that each auxiliary mapping has a positive Jacobian by a homotopy argument. We keep the maps injective all the way through the homotopy with the help of the minimum principle for a certain subharmonic expressio…
Weak Maximum Principle and Application to Swimming at Low Reynolds Number
2018
We refer to [9, 42, 46] for more details about the general concepts and notations introduced in this section.
Constant sign and nodal solutions for parametric anisotropic $(p, 2)$-equations
2021
We consider an anisotropic ▫$(p, 2)$▫-equation, with a parametric and superlinear reaction term.Weshow that for all small values of the parameter the problem has at least five nontrivial smooth solutions, four with constant sign and the fifth nodal (sign-changing). The proofs use tools from critical point theory, truncation and comparison techniques, and critical groups. Spletna objava: 9. 9. 2021. Abstract. Bibliografija: str. 1076.