Search results for "C4"
showing 10 items of 385 documents
Perron's method for the porous medium equation
2016
O. Perron introduced his celebrated method for the Dirichlet problem for harmonic functions in 1923. The method produces two solution candidates for given boundary values, an upper solution and a lower solution. A central issue is then to determine when the two solutions are actually the same function. The classical result in this direction is Wiener’s resolutivity theorem: the upper and lower solutions coincide for all continuous boundary values. We discuss the resolutivity theorem and the related notions for the porous medium equation ut −∆u = 0
Psychological aspects in children affected by duchenne de boulogne muscular dystrophy.
2012
Impairment of intelligence in Duchenne muscular dystrophy (DMD) patients was described by Duchenne de Boulogne himself in 1868. Further studies report intelligence disorders with mayor impairment of memory. The aim of the present study was to assess the presence of affective and personality disorders in a group of children affected by DMD. Twenty six male DMD patients, mean age eleven and four months years old, were assessed for their affective and personality disorder. Only eight subjects had a total IQ below average with major difficulties in verbal and visual-spatial memory, comprehension, arithmetic and vocabulary. All the subjects presented some disorders: tendency to marginalization a…
A wavelet-based tool for studying non-periodicity
2010
This paper presents a new numerical approach to the study of non-periodicity in signals, which can complement the maximal Lyapunov exponent method for determining chaos transitions of a given dynamical system. The proposed technique is based on the continuous wavelet transform and the wavelet multiresolution analysis. A new parameter, the \textit{scale index}, is introduced and interpreted as a measure of the degree of the signal's non-periodicity. This methodology is successfully applied to three classical dynamical systems: the Bonhoeffer-van der Pol oscillator, the logistic map, and the Henon map.
Overload breakdown in models for photosynthesis
2015
In many models of the Calvin cycle of photosynthesis it is observed that there are solutions where concentrations of key substances belonging to the cycle tend to zero at late times, a phenomenon known as overload breakdown. In this paper we prove theorems about the existence and non-existence of solutions of this type and obtain information on which concentrations tend to zero when overload breakdown occurs. As a starting point we take a model of Pettersson and Ryde-Pettersson which seems to be prone to overload breakdown and a modification of it due to Poolman which was intended to avoid this effect.
Spillovers from the oil sector to the housing market cycle
2017
We assess the spillovers from the oil sector to the housing market cycle using quarterly data for 20 net oil-exporting and -importing industrial countries, and employing continuous- and discrete-time duration models. We do not uncover a statistically significant difference in the average duration of booms and normal times in the housing markets of those net oil-importers and net oil-exporters. Similarly, the degree of exposure to commodity price fluctuations does not seem to significantly affect the housing market cycle. However, we find that housing booms are shorter when oil prices increase than housing busts when oil prices decrease. We also show that the net oil-importers are more vulne…
One swallow does not make a summer: episodes and persistence in high growth
2021
This paper analyzes firms’ episodes (spells) of high growth (HG) using a sample of Spanish manufacturing firms observed over two decades. The use of duration models allows us to investigate the following: (i) the probability of experiencing HG episodes, (ii) persistence in HG, and (iii) the determinants of the transitions in and out of the HG state and whether their impact varies over the business cycle. We find that about half of the firms experience at least one HG episode, but they seldom experience more than one. Moreover, high-growth status is rarely repeated due to high first-year selection. Yet, in subsequent years beyond the first one, the hazard rate from HG status falls substantia…
Microbial strategies to exploit host cells
2005
The European Research Conference (EURESCO) on Spatial and Temporal Dynamics of the Endomembrane System was held in sunny San Feliu de Guixols, Spain, between 16 and 21 October 2004. The conference was organized by D. Holden and H. Stenmark ![][1] By bringing together scientists from the fields of microbiology and cell biology, the European Research Conference (EURESCO) on ‘Spatial and Temporal Dynamics of the Endomembrane System’ combined the best of both worlds at the intersection where intracellular pathogens and host cells meet. The mixture of studies, which focused on the molecular mechanisms behind endocytic and secretory transport, and the pathogenic microbes that exploit these pathwa…
Genetic basis of human complement C4A deficiency. Detection of a point mutation leading to nonexpression.
1993
Abstract The fourth component of the human complement system (C4) is coded for by two genes, C4A and C4B, located within the MHC. Null alleles of C4 (C4Q0) are defined by the absence of C4 protein in plasma. These null alleles are due either to large gene deletions or to nonexpression of the respective genes. In a previous study, evidence was obtained for nonexpressed defective genes at the C4A locus, and for gene conversion at the C4B locus. To further characterize the molecular basis of these non-expressed C4A genes, we selected nine pairs of PCR primers from flanking genomic intron sequences to amplify all 41 exons from individuals with a defective C4A gene. The amplified products were s…
Health care and societal costs of the management of children and adolescents with attention-deficit/hyperactivity disorder in Spain : a descriptive a…
2017
Background Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental condition in childhood (5.3% to 7.1% worldwide prevalence), with substantial overall financial burden to children/adolescents, their families, and society. The aims of this study were to describe the clinical characteristics of children and adolescents with ADHD in Spain, estimate the associated direct/indirect costs of the disorder, and assess whether the characteristics and financial costs differed between children/adolescents adequately responding to currently available pharmacotherapies compared with children/adolescents for whom pharmacotherapies failed. Methods This was a multicenter, cross-secti…
Acute toxicity of experimental fertilizers made of blood meal, spent coffee ground and biomass ash
2017
Abstract The study presents the results of research on the acute toxicity of a fertilizer formulas made of spent coffee ground (SCG) with addition of ash from low-temperature combustion of biomass or ash with an admixture of magnesium sulphate and blood meal. The experimental fertilizer formulas included also rape oil used as a plasticizer for controlling the nutrients release from the fertiliser. Mustard (Sinapis alba L.), oats (Avena sativa sp. L.), cucumber (Cucumis sativus L.) and cress (Lepidium sativum L.) were used as test plants species in the experiment. The toxicity tests were performed using a standard procedure of 72 h with the use of Phytotoxkit microbiotest and fertilizer appl…