Polarized–unpolarized ground state of small polycyclic aromatic hydrocarbons

Do polyacenes, circumacenes, periacenes, nanographenes, and graphene nanoribbons show a spin polarized ground state? In this work, we present monodeterminantal (Hartree–Fock (HF) and density functional theory (DFT) types), and multideterminantal calculations (Møller–Plesset and Coupled Cluster), for several families of unsaturated organic molecules (n-Acenes, n-Periacenes and n-Circumacenes). All HF calculations and many DFT show a spin-polarized (antiferromagnetic) ground state, in agreement with previous calculations. Nevertheless, the multideterminantal calculations, carried out with perturbative and variational wavefunctions, show that the more stable state is obtained starting from the unpolarized HF wavefunction. The trend of the stabilization of wavefunctions (polarized or unpolarized) with respect to exchange and correlation potentials, and to the number of benzene rings, has been analyzed. A study of the spin (〈Ŝ2〉) and the spin density on the carbon atoms has also been carried out.Spanish MCYT; contract grant numbers: FIS2008-06743 and FIS2009-10325. Universidad de Alicante

Accelerating Convergence of Fluid Dynamics Simulations with Convolutional Neural Networks

A novel technique to accelerate optimization-driven aerodynamic shape design is presented in the paper. The methodology of optimization-driven design is based on the automated evaluation of many similar shapes which are generated according to the output of an optimization algorithm. The vast amount of numerical simulations makes this process slow but the resource-intensive simulation part can be changed to so-called surrogate models or metamodels. However, there isn’t any guarantee of this solution’s accuracy. The motivation of this work was to develop an acceleration method to speedup optimization sessions without losing accuracy. Accordingly, the numerical simulation is kept in the pipeline but it is initialized with a velocity field that is close to the expected solution. This velocity field is generated by a predictive initializer that is based on a convolutional deep neural network. The network has to be trained before using it for initializing numerical simulations; the data generation, the training and the testing of the network are described in the paper as well. The performance of predictive initializing is presented through a test problem based on a deformable u-bend geometry. It has been found that the speedup in the convergence speed of the numerical simulation depends on the resolution of the predictive initializer and on the handling of velocities in the near-wall cells. A speedup of 13 % was achieved on a test set of 500 geometries that were not seen by the initializer before

Children or educators in need of special support : To include all children with the help of special educational practice and procedures in preschool

Syftet med vår studie är att bidra med kunskap om hur förskollärare beskriver barn i behov av särskilt stöd och hur de resonerar kring att inkludera alla barn på förskolan. Vi undersöker även vilken roll specialpedagogen har till förskollärare och barn i behov av särskilt stöd på förskolan. I förskolan placeras alla barn, oavsett behov, eftersom det inte finns några andra skolformer och därför blir inkludering en intressant fråga. Som blivande specialpedagoger undrar vi över vilka möjligheter förskollärare har för att inkludera alla barn, med olika behov på förskolan, samt hur specialpedagogen med sin kompetens kan vara ett stöd för barn och förskollärare. Vår undersökning bygger på en kvalitativ ansats med åtta intervjuade förskollärare.  Våra frågeställningar är: Hur beskriver förskollärare barn i behov av särskilt stöd? Hur resonerar förskollärare kring förutsättningar för att inkludera alla barn på förskolan? Vilken roll har specialpedagogen till förskollärare och barn med behov av särskilt stöd på förskolan, enligt förskollärarna?  Teoretiska ansatser i studien är det sociokulturella perspektivet samt de specialpedagogiska perspektiven, kategoriska, relationella och dilemmaperspektivet.  Sammanfattningsvis pekar resultatet på att barn i behov av särskilt stöd beskrivs kunna vara ett barn med språksvårigheter, alltifrån att vara tillbakadragen till att kunna vara utåtagerande som behöver stöttning och vägledning för att klara vardagen och det sociala samspelet. Det sociokulturella perspektivet genomsyrar pedagogernas förhållningssätt då kommunikation och interaktion visar sig vara viktiga begrepp i arbetet med att inkludera alla barn. Vidare är det relationella synsättet bärande i studien då förskollärarna anser att arbetssätt samt miljö ska förändras och anpassas så att alla barn kan delta på lika villkor i förskolan verksamhet. Dilemmaperspektivet blir synligt då resultatet visar att förutsättningarna är olika ute på förskolorna kring bland annat samarbete med andra professioner, barngrupper och personalresurser.  Specialpedagogiska implikationer som lyfts i studien är pedagogernas samarbete med specialpedagogen som genom sitt förebyggande arbete hjälper och stödjer med olika samtalsmetoder, förhållningssätt och språkstödjande material att inkluderar alla barn i förskolan.The purpose of our study is to contribute knowledge about how preschool teachers describes children in need of special support and how they discuss about including all children in the preschool. We also investigate how the role of the special educator is for preschool teachers and children with needs at preschool. In preschool, all the children are placed, regardless of need, because there are no other forms of schooling and therefore inclusion becomes an interesting issue. As future special educators, we wonder what opportunities preschool teachers have to include all children, with special needs in preschool, and how the special educator with his competence can be a support for children and educators. Our study is based on qualitive interviews with eight preschool teachers. Our questions are: How are children in special needs described by the preschool teachers? How preschool teachers discuss about the conditions for including all children in preschool? What role does the special educator have in relation to the preschool teachers and the children in need of special support at the preschool, according to preschool teachers? The theoretical approaches in the study are the socio-cultural perspectives, the special educational perspectives as well as the categorical, relational and quandary perspectives. In summary the result indicates that children with special needs are defined as children with speech difficulties, from being withdrawn to being outspoken with the need of extra support and guidance to cope with everyday life and social interactions. The socio-cultural perspective permeates the special educator´s approach as communication and interaction prove to be important concepts in the work of including all children. Furthermore, the relational approach is fundamental in the study as the preschool teachers believe that work procedures and the environment should be changed and adapted so that all children can participate on equal terms in the preschool´s activities. The quandary perspective becomes obvious as the results show that the conditions are different in the preschools when it comes to collaboration with other professions, groups of children and staff resources among other things. The special educational implication that has been highlighted in the study is the collaboration with special educators, who through their preventive work help and support the children by using different conversational methods, approaches and speech encouraging material