880 research outputs found
How to Characterize Cylindrical Magnetic Nanowires
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
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
Cover plants and mineral nitrogen: effects on organic matter fractions in an oxisol under no-tillage in the cerrado
Flavonoids in phylloclades discriminate endemic Semele androgyna chemotypes from Madeira
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
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
The mean-square radii of the molecules He, HeLi,
HeLi and HeNa 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 in a triatomic molecule are estimated to be of de order of
, where is the dimer and the
trimer binding energies, and is a constant (varying from
to ) that depends on the ratio between and . 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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