880 research outputs found

    How to Characterize Cylindrical Magnetic Nanowires

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    Cylindrical magnetic nanowires made through the help of nanoporous alumina templates are being fabricated and characterized since the beginning of 2000. They are still actively investigated nowadays, mainly due to their various promising applications, ranging from high-density magnetic recording to high-frequency devices, passing by sensors, and biomedical applications. They also represent suitable systems in order to study the dimensionality effects on a given material. With time, the development in fabrication techniques allowed to increase the obtained nanowire complexity (controlled crystallinity, modulated composition and/or geometry, range of materials, etc.), while the improvements in nanomanipulation permitted to fabricate system based either on arrays or on single nanowires. On the other side, their increased complexity requires specific physical characterization methods, due to their particular features such as high anisotropy, small magnetic volume, dipolar interaction field between them, and interesting electronic properties. The aim of this chapter was to offer an ample overview of the magnetic, electric, and physical characterization techniques that are suitable for cylindrical magnetic nanowire investigation, of what is the specific care that one needs to take into account and which information will be extracted, with typical and varied examples

    The Influence Of Assistive Technology Devices On The Performance Of Activities By Visually Impaired

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    Objective: To establish the influence of assistive technology devices (ATDs) on the performance of activities by visually impaired schoolchildren in the resource room. Methods: A qualitative study that comprised observation and an educational intervention in the resource room. The study population comprised six visually impaired schoolchildren aged 12 to 14 years old. The participants were subjected to an eye examination, prescribed ATDs comprising optical and non-optical devices, and provided an orientation on the use of computers. The participants were assessed based on eye/object distance, font size, and time to read a computer screen and printed text. Results: The ophthalmological conditions included corneal opacity, retinochoroiditis, retinopathy of prematurity, aniridia, and congenital cataracts. Far visual acuity varied from 20/200 to 20/800 and near visual acuity from 0.8 to 6 M. Telescopes, spherical lenses, and support magnifying glasses were prescribed. Three out of five participants with low vision after intervention could decrease the font size on the screen computer, and most participants (83.3%) reduced their reading time at the second observation session. Relative to the printed text, all the participants with low vision were able to read text written in smaller font sizes and reduced their reading time at the second observation session. Conclusion: Reading skills improved after the use of ATDs, which allowed the participants to perform their school tasks equally to their classmates.732103107Resnikoff, S., Pascolini, D., Etya'ale, D., Kocur, I., Pararajasegaram, R., Pokharel, G.P., Global data on visual impairment in the year 2002 (2004) Bull World HealthOrgan., 82 (11), pp. 844-851Visual standards: aspects and ranges of vision loss with emphasis on population surveys. (2002) 29th International Congress of Ophthalmology., , www.icoph.org/pdf/visualstandardsreport.pdf, International Council of Ophthalmology [Internet]. Sydney, Australia, April. Available fromAmorim, A., Paraguay, A.I., Barbosa, E.M., Spelta, L.L., Martinelli, M.A., Bersch, R.C., Comissão temática 1:conceituação e estudo de normas. (2009), pp. 13-39. , http://www.pessoacomdeficiencia.gov.br/app/sites/default/files/publicacoes/livro-tecnologia-assistiva.pdf, In: Brasil. Subsecretaria Nacional de Promoção dos Direitos da Pessoa com DeficiênciaTecnologia Assistiva. Brasília: Corde;Burton, M., Nieuwenhuijsen, E.R., Epstein, M.J., Computer-related assistivetechnology: satisfaction and experiences among users with disabilities (2008) AssistTechnol., 20 (2), pp. 99-106. , quiz 84-85Fok, D., Polgar, J.M., Shaw, L., Jutai, J.W., Low vision assistive technology deviceusage and importance in daily occupations (2011) Work., 39 (1), pp. 37-48Alves, C.C., Monteiro, G.B., Rabello, S., Gasparetto, M.E., de Carvalho, K.M., Assistivetechnology applied to education of students with visual impairment (2009) Rev Panam Salud Publica., 26 (2), pp. 148-152Carvalho, K.M., Freitas, C.C., Kimolto, E.M., Gasparetto, M.E., [Assessment and management of low vision students attended in a room with resources for visual deficiency] (2002) Arq Bras Oftalmol., 65 (4), pp. 445-449. , Portuguesehttp://www.prg.unicamp.br/auxiliosopticos/, Auxílios ópticos Faculdade de Ciências Médicas Universidade Estadual de Campinas. [Optical aids]. Available fromArrigucci Jr., D., Os melhores contos de Rubem Braga. (1997), São Paulo: Global;Pacheco, J., Quando eu for grande quero ir à primavera e outras histórias. (2003), São Paulo: Didática Suplegraf;Montilha, R.C., Temporini, E.R., Nobre, M.I., Gasparetto, M.E., Kara-José, N., [Utilization of optical devices and equipments by students with visual impairment] (2006) Arq Bras Oftalmol., 69 (2), pp. 207-211. , PortugueseHerrero, M.J., Mateus, G.G., García, M., Ramón, M.P., Moasquete, M.J., Characteristics of reading in people with low vision. (1997), Madrid: Once;Freire, F.M., Escrita/leitura e computadores: o uso do editor de texto na escolar. (2003), In: Valente JA, Prado ME, Almeida ME, editors. Educação a distância via internet. São Paulo: AvercampChiang, M.F., Cole, R.G., Gupta, S., Kaiser, G.E., Starren, J.B., Computer and World WideWeb accessibility by visually disabled patients: problems and solutions (2005) SurvOphthalmol., 50 (4), pp. 394-405. , ReviewWatson, A.H., Ito, M., Smith, R.O., Andersen, L.T., Effect of assistive technology in apublic school setting (2010) Am J Occup Ther., 64 (1), pp. 18-2

    Flavonoids in phylloclades discriminate endemic Semele androgyna chemotypes from Madeira

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    Thirty-five randomly-collected Semele androgyna Kunth samples were screened by RP-HPLC for their phenolic composition. Fraction analysis allowed the detection of 17 different compounds. According to their retention times and UV spectra obtained by diode array analysis, these phenolics represent three classes: phenolic acids, flavones and flavonols. Co-chromatography with specific standards enabled identification of quercetin, rutin and quercitrin in Semele tissues for the first time. Polymorphism based on phenolic composition was evaluated using multivariate analysis and showed four distinct S. androgyna clusters. This polymorphism was not associated with morphological diversity or different in ambient light intensities. Biochemical differentiation is thus present in this species. The application of multivariate analysis techniques to RP-HPLC data has allowed the classification of samples into two groups, previously proposed on the basis of morphological and cytotaxonomical information. Therefore, the use of phenolics as chemotaxonomic markers in Semele is highly recommended because of its diagnostic value, even at a subspecies level. Discriminant canonical analysis and Mahalanobis distances confirmed these clusters as recognisable chemosystematic units. However, these units do not support the separation of S. pterygophora.The Portuguese Foundation for Science and Technology (FCT) funded this work through the Centre of Macaronesian Studies (CEM). The authors are grateful to the Madeiran Centre of Science and Technology (CITMA), the Berardo Foundation and European Social Funding for financial assistance given during execution of this work. The assistance rendered by Mr Rogério Correia during field collection is gratefully acknowledged.info:eu-repo/semantics/publishedVersio

    COMPACTAÇÃO DE SOLOS EM LABORATÓRIO: EFEITO DO DIÂMETRO E DO NÚMERO DE CAMADAS DO CORPO DE PROVA

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    RESUMONeste trabalho, estudou-se a influência do diâmetro e do número de camadas do corpo de prova nas curvas de compactação de laboratório e na resistência mecânica de dois solos residuais de gnaisse da Zona da Mata Norte de Minas Gerais, respectivamente, de texturas argilo-areno-siltosa (Solo 1) e areno-silto-argilosa (Solo 2), com vistas à construção de estradas florestais. Além dos resultados dos ensaios de compactação, determinou-se a resistência à compressão não confinada dos solos empregando corpos de prova compactados na umidade ótima (wot) e nos teores de umidade 3% abaixo e 2% acima, considerando como referência a energia de compactação do ensaio Proctor normal e empregando corpos de prova compactados em uma, duas e três camadas, bem como nos diâmetros de 35 mm, 73 mm e 100 mm, com nove repetições. Para fins práticos de engenharia e com base em análise estatística aplicada aos parâmetros massa específica aparente seca e resistência à compressão não confinada, pode-se concluir que: (i) há diferenças significativas entre as compactações realizadas em uma e em três camadas, não ocorrendo o mesmo nas compactações realizadas em duas e em três camadas, para ambos os solos; e (ii) há diferenças significativas entre a compactação de corpos de prova de diâmetro 100 mm e os demais de 73 mm e 35 mm, para o solo 1 (argiloso), bem como há também diferenças apenas no ramo seco da curva de compactação, para o solo 2 (arenoso)

    Scaling predictions for radii of weakly bound triatomic molecules

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    The mean-square radii of the molecules 4^4He3_3, 4^4He26_2-^6Li, 4^4He27_2-^7Li and 4^4He223_2-^{23}Na are calculated using a three-body model with contact interactions. They are obtained from a universal scaling function calculated within a renormalized scheme for three particles interacting through pairwise Dirac-delta interaction. The root-mean-square distance between two atoms of mass mAm_A in a triatomic molecule are estimated to be of de order of C2/[mA(E3E2)]{\cal C}\sqrt{\hbar^2/[m_A(E_3-E_2)]}, where E2E_2 is the dimer and E3E_3 the trimer binding energies, and C{\cal C} is a constant (varying from 0.6\sim 0.6 to 1\sim 1) that depends on the ratio between E2E_2 and E3E_3. Considering previous estimates for the trimer energies, we also predict the sizes of Rubidium and Sodium trimers in atomic traps.Comment: 7 pages, 2 figure
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