Search results for "Stability"
showing 10 items of 3085 documents
Pattern formation driven by cross–diffusion in a 2D domain
2012
Abstract In this work we investigate the process of pattern formation in a two dimensional domain for a reaction–diffusion system with nonlinear diffusion terms and the competitive Lotka–Volterra kinetics. The linear stability analysis shows that cross-diffusion, through Turing bifurcation, is the key mechanism for the formation of spatial patterns. We show that the bifurcation can be regular, degenerate non-resonant and resonant. We use multiple scales expansions to derive the amplitude equations appropriate for each case and show that the system supports patterns like rolls, squares, mixed-mode patterns, supersquares, and hexagonal patterns.
New Roles for Media in the Western Balkans
2017
After almost 20 years of political instability and ongoing conflicts in the Western Balkans, the region is still haunted by the past, and there is an ongoing synergy of influence between media and the political sector. Media in this region have frequently been criticized for fueling conflicts, instigating ethnic hatred and taking political sides. This article suggests a new research agenda in the practice of transitional journalism in this part of Southeastern Europe. This research strand combines elements from troubled pasts, war reporting, peace journalism and issues of transitional justice. This article analyzes how journalists in the Western Balkans consider the roles of journalism in t…
NREM Sleep Instability in Pediatric Migraine Without Aura
2019
Children with migraine headaches appear to have a range of sleep disturbances. The aim of the present study was to assess the NREM sleep instability in a population of school-aged individuals affected by migraine without aura (MoA). Thirty-three children with MoA (20 males, 13 females, mean age 10.45 ± 2.06 years) underwent to overnight Polysomnographic (PSG) recordings and Cyclic Alternating Pattern (CAP) analyses accordingly with international criteria. MoA group showed a reduction in sleep duration parameters (TIB, SPT, TST; p ≤ 0.001 for all) and in arousal index during REM sleep and an increase in awakenings per hour (AWK/h) vs. Controls (C) (p = 0.008). In particular, MoA children sho…
One-Year Follow-Up Diagnostic Stability of Autism Spectrum Disorder Diagnosis in a Clinical Sample of Children and Toddlers
2020
Some studies show that the diagnosis of Autism Spectrum Disorder could be considered reliable and stable in children aged 18 to 24 months. Nevertheless, the diagnostic stability of early ASD diagnosis has not yet been fully demonstrated. This observational study examines the one-year diagnostic stability of autism spectrum disorder diagnosis in a clinical sample of 147 children diagnosed between 18 and 48 months of age. The ADOS-2 scores were used in order to stratify children in three levels of symptom severity: Autism (AD; comparison score 5–7), Autism Spectrum Disorder (ASD; comparison score 3–4), and Sub-Threshold Symptoms; (STS; comparison score 1–2). Results: Overall…
Victimization at school: relationship of parenting and functional-dysfunctional developmental variables
2015
El presente estudio tiene como principal objetivo analizar elpapel diferencial de la crianza (apoyo y comunicación versus control), devariables funcionales del desarrollo (empatía y mecanismos de afrontamientofuncionales) y las variables disfuncionales (inestabilidad emocional yafrontamiento improductivo) en la victimización ocurrida en el entorno escolar,o por el contrario, con el apego entre pares. Participaron en el estudio418 alumnos, 224 chicas y 194 chicos adolescentes, entre 13 y 14 años,escolarizados en los niveles de 3º y 4º curso de Educación SecundariaObligatoria. Para analizar estas relaciones se llevó a cabo un modelo deecuaciones estructurales EQS. Los resultados obtenidos mue…
The Importance and Role of Social Policy in Maintaining Macroeconomic Stability
2021
Pension systems have the role of reducing the financial risk associated with the loss of the ability to carry out professional activities for income, a risk that determines poverty and is associated with severe material deprivation. The objective of this chapter is to emphasize the role of social policy in society and in macroeconomic policies in order to maintain socioeconomic stability and promote sustainable economic growth.
Complex formation of Tb3+ with glycolate, D-gluconate and α-isosaccharinate in neutral aqueous perchlorate solutions
2003
Summary An electromigration technique was used for measurements of metal-ligand formation constants of non-carrier-free 160Tb3+ with glycolate, D-gluconate and α-isosaccharinate ligands. The overall ion mobilities of Tb at different concentrations of the ligands were measured in chemically inert perchlorate solutions (pH 7 and T= 298.1K) with an overall ionic strength μ = 0.1. The stepwise stoichiometric stability constants are: Tb3+/glycolate: log K 1=2.72(18), log K 2=1.73(19), log K 3= 1.12(17), Tb3+/D-gluconate: log K 1=2.96(11), log K 2=2.60(11), log K 3=1.13(9), Tb3+/α-ISA: log K 1=3.07(8), log K 2 = 2.69(11), log K 3 = 1.80(12).
Stochastic resonance in a tunnel diode.
1994
We study stochastic resonance in a fast bistable electronic system: a tunnel diode. We investigate the phenomenon in a higher frequency regime than that studied in previous experiments. Detailed measurements of the output signal are reported for two values of the frequency of the periodic signal: ${\mathit{f}}_{\mathit{s}}$=1 kHz and ${\mathit{f}}_{\mathit{s}}$=10 kHz. We observe, in one case (${\mathit{f}}_{\mathit{s}}$=1 kHz), a nonmonotonic behavior characterized by a sharp dip in the output noise level measured at the frequency of the driving signal.
Reference-Plane Invariant Method for Measuring Electromagnetic Parameters of Materials
2010
This paper presents a simple and effective wideband method for the determination of material properties, such as the complex index of refraction and the complex permittivity and permeability. The method is explicit (non-iterative) and reference-plane invariant: it uses a certain combination of scattering parameters in conjunction with group-velocity data. This technique can be used to characterize both dielectric and magnetic materials. The proposed method is verified experimentally within a frequency range between 2 to 18 GHz on polytetrafluoroethylene and polyvinylchloride samples. A comprehensive error and stability analysis reveals that, similar to other methods based on transmission/re…
Tuning the dielectric properties of hafnium silicate films
2007
The influence of Si concentration in hafnium silicate dielectrics on thermal stability and dielectric permittivity was analyzed. A phase diagram was developed using GIXRD and FTIR measurement. The stabilization of the ''higher-k'' cubic/tetragonal phase for annealing temperatures up to 1000^oC with a steady increase in capacitance was demonstrated for Hf"0"."9"4Si"0"."0"6O"2 films. It was also shown that the stabilization of nano-crystalline Hf"0"."8"0Si"0"."2"0O"2 films can be realized for annealing temperatures up to 900^oC. The influence of TiN electrodes on the dielectric constant and the leakage current characteristic was also investigated. A permittivity increase for annealing tempera…