90 research outputs found
A Series Solution of the Cauchy Problem for Turing Reaction-diffusion Model
In this paper, the series pattern solution of the Cauchy problem for Turing reaction-diffusion model is obtained by using the homotopy analysis method (HAM). Turing reaction-diffusion model is nonlinear reaction-diffusion system which usually has power-law nonlinearities or may be rewritten in the form of power-law nonlinearities. Using the HAM, it is possible to find the exact solution or an approximate solution of the problem. This technique provides a series of functions which converges rapidly to the exact solution of the problem. The efficiency of the approach will be shown by applying the procedure on two problems. Furthermore, the so-called homotopy-Pade technique (HPT) is applied to enlarge the convergence region and rate of solution series given by the HAM
Inverse scattering at fixed energy on surfaces with Euclidean ends
On a fixed Riemann surface with Euclidean ends and genus ,
we show that, under a topological condition, the scattering matrix S_V(\la)
at frequency \la > 0 for the operator determines the potential
if for all
and for some , where denotes the distance
from to a fixed point . The topological condition is given by
for and by if . In \rr^2 this
implies that the operator S_V(\la) determines any potential
such that for all .Comment: 21 page
On the utilization of modified red mud in dimethyl disulfide and methyl mercaptan emission abatement
In this paper, a novel application of industrial waste, namely red mud (RM), in the
abatement of two malodorous and harmful sulfur compounds, dimethyl disulfide (DMDS) and
methyl mercaptan (MM), is presented. The effects of calcination and activations with hydrochloric
acid or a mixture of hydrochloric and orthophosphoric acid on the properties and performance of RM
are compared using laboratory-scale experiments. The RM-based materials were characterized by
XRF, XRD, FE-SEM, N2
-physisorption, TGA/DTA, and FTIR analyses. RM exhibits very promising
catalytic properties in the abatement of both DMDS and MM. The hydrochloric acid-activated RM
was the most active in both cases, which was explained by its rather high specific surface area
(144 m2 g
â1
), higher contents of Fe2O3 and TiO2, as well as lower content of phosphorus. For both
DMDS and MM, the main oxidation products were sulfur dioxide, carbon monoxide, and carbon
dioxide. DMDS was observed as a reaction intermediate in MM oxidation. While the final conversions
of DMDS and MM were high, the oxidation was not complete, indicated by the formation of carbon
monoxide. Nevertheless, the modified RM appears as a very interesting alternative to the existing
DMDS and MM abatement catalysts.Web of Science121art. no.
Inverse problems with partial data for a magnetic Schr\"odinger operator in an infinite slab and on a bounded domain
In this paper we study inverse boundary value problems with partial data for
the magnetic Schr\"odinger operator. In the case of an infinite slab in ,
, we establish that the magnetic field and the electric potential can
be determined uniquely, when the Dirichlet and Neumann data are given either on
the different boundary hyperplanes of the slab or on the same hyperplane. This
is a generalization of the results of [41], obtained for the Schr\"odinger
operator without magnetic potentials. In the case of a bounded domain in ,
, extending the results of [2], we show the unique determination of the
magnetic field and electric potential from the Dirichlet and Neumann data,
given on two arbitrary open subsets of the boundary, provided that the magnetic
and electric potentials are known in a neighborhood of the boundary.
Generalizing the results of [31], we also obtain uniqueness results for the
magnetic Schr\"odinger operator, when the Dirichlet and Neumann data are known
on the same part of the boundary, assuming that the inaccessible part of the
boundary is a part of a hyperplane
Key components of learning ecologies: a Delphi assessment
This is the accepted version of the following article: GonzĂĄlezâSanmamed, M. , MuñozâCarril, P. and SantosâCaamaño, F. (2019), Key components of learning ecologies: A Delphi assessment. Br J Educ Technol, 50: 1639-1655, which has been published in final form at https://doi.org/10.1111/bjet.12805. This article may be used for
non-commercial purposes in accordance with the Wiley Self-Archiving Policy (http://www.wileyauthors.com/self-archiving)The educational landscape has changed in recent years, requiring reflection about new pedagogical methods and theories. There are three important perspectives as drivers of pedagogical reflection: lifelong and lifeâwide learning, the idea of learning as a social construct in which internal elements and changing external factors converge, and the recognition of technology as a resource that can promote ubiquitous and expanded learning. Learning ecology has been proposed as a conceptual and empirical framework, but its still emergent nature along with its multidimensionality and complexity require further exploration. The Delphi study we present as part of a broader research project aims to identify the components of learning ecologies. Three panel rounds with international experts were carried out, after which two important dimensions emerged in the structure of learning ecologies. The first is related to intrinsic âlearning dispositions,â which is made up of three categories: the subject's ideas about learning, their motivations and expectations. The second dimension, called âlearning processes,â comprises four components: relationships, resources, actions and context. The identification of the components of learning ecologies and their influence on formal, nonâformal and informal training processes will provide guidance for educational policies and help to better organize training programmesWe thank the Spanish Ministry of Economy and Competitiveness for their support of our study under a research project entitled âHow the best University Teachers Learn: Impact on Learning Ecologies on Quality of Teachingâ (ECO4LEARNâHE) (Reference: EDU2015â67907âR)S
Cognitive decline in Huntington's disease expansion gene carriers
BACKGROUND: In Huntington's Disease (HD) cognitive decline can occur before unequivocal motor signs become apparent. As cognitive decline often starts early in the course of the disease and has a progressive nature over time, cognition can be regarded as a key target for symptomatic treatment. The specific progressive profile of cognitive decline over time is unknown.
OBJECTIVE: The aim of this study is to quantify the progression of cognitive decline across all HD stages, from pre-motormanifest to advanced HD, and to investigate if CAG length mediates cognitive decline.
METHODS: In the European REGISTRY study 2669 HD expansion gene carriers underwent annual cognitive assessment. General linear mixed models were used to model the cognitive decline for each cognitive task across all disease stages. Additionally, a model was developed to evaluate the cognitive decline based on CAG length and age rather than disease stage.
RESULTS: There was significant cognitive decline on all administered tasks throughout pre-motormanifest (close to estimated disease onset) participants and the subsequent motormanifest participants from stage 1 to stage 4. Performance on the Stroop Word and Stroop Color tests additionally declined significantly across the two pre-motormanifest groups: far and close to estimated disease onset.
The evaluation of cognition performance in relation to CAG length and age revealed a more rapid cognitive decline in participants with longer CAG length than participants with shorter CAG length over time.
CONCLUSION: Cognitive performance already shows decline in pre-motormanifest HD gene expansion carriers and gradually worsens to late stage HD. HD gene expansion carriers with certain CAG length have their own cognitive profile, i.e., longer CAG length is associated with more rapid decline
The V471A polymorphism in autophagy-related gene ATG7 modifies age at onset specifically in Italian Huntington disease patients
The cause of Huntington disease (HD) is a polyglutamine repeat expansion of more than 36 units in the huntingtin protein, which is inversely correlated with the age at onset of the disease. However, additional genetic factors are believed to modify the course and the age at onset of HD. Recently, we identified the V471A polymorphism in the autophagy-related gene ATG7, a key component of the autophagy pathway that plays an important role in HD pathogenesis, to be associated with the age at onset in a large group of European Huntington disease patients. To confirm this association in a second independent patient cohort, we analysed the ATG7 V471A polymorphism in additional 1,464 European HD patients of the âREGISTRYâ cohort from the European Huntington Disease Network (EHDN). In the entire REGISTRY cohort we could not confirm a modifying effect of the ATG7 V471A polymorphism. However, analysing a modifying effect of ATG7 in these REGISTRY patients and in patients of our previous HD cohort according to their ethnic origin, we identified a significant effect of the ATG7 V471A polymorphism on the HD age at onset only in the Italian population (327 patients). In these Italian patients, the polymorphism is associated with a 6-years earlier disease onset and thus seems to have an aggravating effect. We could specify the role of ATG7 as a genetic modifier for HD particularly in the Italian population. This result affirms the modifying influence of the autophagic pathway on the course of HD, but also suggests population-specific modifying mechanisms in HD pathogenesis
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