2,487 research outputs found
Rolling/Slipping Motion of Euler's Disk
We present an experimental study of the motion of a circular disk spun onto a
table. With the help of a high speed video system, the temporal evolutions of
(i) the inclination angle , (ii) the angular velocity and
(iii) the precession rate are studied. The influence of the mass of
the disk and the friction between the disk and the supporting surface are
considered. %The motions of disks with different masses and over different
surfaces are studied. The inclination angle and the angular velocity
are observed to decrease according to a power law. We also show that the
precession rate diverges as the disk stops. Exponents are measured
very near the collapse as well as on long range times. Collapsing times have
been also measured. The results are compared with previous theoretical and
experimental works. The major source of energy dissipation is found to be the
slipping of the disk on the plane.Comment: Submitted for publication (2003) - 6page
Emergence of supersymmetry on the surface of three dimensional topological insulators
We propose two possible experimental realizations of a 2+1 dimensional
spacetime supersymmetry at a quantum critical point on the surface of three
dimensional topological insulators. The quantum critical point between the
semi-metallic state with one Dirac fermion and the s-wave superconducting state
on the surface is described by a supersymmetric conformal field theory within
-expansion. We predict the exact voltage dependence of the
differential conductance at the supersymmetric critical point.Comment: 8 pages, 2 figures; published versio
MASS TRANSFER CORRELATION FOR THE REMOVAL OF COPPER IONS FROM WASTEWATER
One of the biggest problems with ore processing in extractive metallurgical industries is the high toxicity of the heavy metals waste content (e.g., copper, lead, nickel and chrome). This work investigates the copper (II) íons removal from aqueous solutions in concentrations up to 1000 ppm. Therefore, a fluidized bed electrolytic reactor was used with flow-by configuration considered as a hopeful method due to the large specific surface area and the high mass transfer rate. The performance of the electrochemical reactor was investigated by using different porosities. Dimensionless Sherwood and Reynolds numbers were correlated to characterize the mass transport properties of the reactor, and they were fitted to the equation Sh = a.Reb.Sc1/3
Low Dose Thalidomide for Treatment of Resistant Discoid Lupus Erythematosus. A Case Report
Discoid lupus erythematosus (DLE) is a chronic, indolent, disfiguring disease that is characterized by scaly, erythematous, disk-shaped patches and plaques followed by atrophy, scarring and depigmentation. In a small number of patients, it is refractory to standard therapies. In several studies, thalidomide has been reported to be an effective treatment in those cases. The most fearful side effects are teratogenicity and neuropathy. Adequate counseling and vigilance must be given to the patients.
We report a 45-year-old Portuguese woman who presented with a 20-year history of severe facial and scalp DLE confirmed by histopathology. For several years, it failed to respond to several therapies, including topical, intralesional and oral corticosteroids, hydroxychloroquine, methotrexate, azathioprine and topical tacrolimus. Thalidomide was initiated at a dosage of 50mg/day and the skin lesions had improved dramatically after three weeks with complete clinical remission. Two months later, the dose was reduced to 50mg, five days per week without disease rebound. The patient´s concomitant medications during the treatment included sunscreen, hydroxycholoroquine, enoxaparin and aspirin to prevent thromboembolic events. Pregnancy testing, routine laboratory and electrocardiography were performed at regular intervals for safety monitoring and the results were within normal limits. Only minor side effects as nausea, constipation and somnolence were noted, however, they improved with dose reduction. Our data confirm that thalidomide therapy is an alternative or adjunctive treatment for patients with severe, chronic DLE that is refractory to standard therapies. In this patient, low-dose thalidomide was an effective treatment with minimal side effects
Human Mobility in Large Cities as a Proxy for Crime
We investigate at the subscale of the neighborhoods of a highly populated
city the incidence of property crimes in terms of both the resident and the
floating population. Our results show that a relevant allometric relation could
only be observed between property crimes and floating population. More
precisely, the evidence of a superlinear behavior indicates that a
disproportional number of property crimes occurs in regions where an increased
flow of people takes place in the city. For comparison, we also found that the
number of crimes of peace disturbance only correlates well, and in a
superlinear fashion too, with the resident population. Our study raises the
interesting possibility that the superlinearity observed in previous studies
[Bettencourt et al., Proc. Natl. Acad. Sci. USA 104, 7301 (2007) and Melo et
al., Sci. Rep. 4, 6239 (2014)] for homicides versus population at the city
scale could have its origin in the fact that the floating population, and not
the resident one, should be taken as the relevant variable determining the
intrinsic microdynamical behavior of the system.Comment: 17 pages, 8 Figure
Produção escrita : o processamento de informação medidado pelo estilo cognitivo e pelo nível de inteligência
O padrão estilístico Dependência-Independência de Campo (DIC) tem sido
relacionado com diversos aspectos da personalidade, procedimentos e
estratégias utilizadas na resolução de problemas ou ponderado numa
agregação de aspectos cognitivos, afectivos e motivacionais, inerentes ao
processamento da informação e resolução de problemas. Apesar da
subsistência da comedida investigação nesta conjectura, formulada por
Witkin, os resultados perduram inconclusivos e pouco consensuais. Neste
estudo, relacionou-se a DIC com a Expressão Escrita das crianças, área
reveladora de grandes dificuldades no processamento de informação e
justificando uma maior atenção de pais e educadores. Esta dificuldade
ocorre nos processos de planificação, de tradução e de revisão do texto
escrito, que explicam toda a complexidade dos procedimentos na produção
de um texto. Participaram neste estudo 92 alunos do 3º e o 4º ano de
escolaridade [45 rapazes e 47 meninas], com idades compreendidas entre os
8 e os 11 anos, e a frequentarem escolas públicas da cidade de Braga. Para
avaliação do estilo cognitivo (DIC) utilizamos o teste Children’s Embedded
Figures Test (CEFT) e para a avaliação da inteligência recorreu-se à prova
Matrizes Coloridas Progressivas de Raven. Os resultados deste estudo
permitem afirmar uma associação significativa do Estilo Cognitivo (DIC)
com a Expressão Escrita das crianças favorecendo os alunos independentes
de campo.Faculdade de Psicologia - Universidade de LisboaSociedade Portuguesa de PsicologiaCGD - Caixa Geral de DepósitosCEGOCSHLPSE - Produtos e Serviços de Estatística, Lda.ProfiForm
Generation of a human iPS cell line from a patient with retinitis pigmentosa due to EYS mutation
Retinitis pigmentosa (RP) is an inherited retinal degenerative disease. Mutations in EYS have been associated with autosomal recessive RP. The human iPS cell line, CABi002-A, derived from peripheral blood mononuclear cells from a patient carrying a heterozygous double mutation in EYS gene was generated by non-integrative reprogramming technology, using hOCT3/4, hSOX2, hc-MYC and hKLF4 reprogramming factors. Pluripotency and differentiation capacity were assessed by immunocytochemistry and RT-PCR. This iPSC line can be further differentiated towards the affected cells to understand the pathophysiology of the disease and test new therapeutic strategies.Cellex FoundationFundación Progreso y Salu
Late Bronze Age metallic depositions in the AssureiraValley. The case study of Moinhos de Golas site (Solveira, Montalegre, Northern Portugal)
[PT] Este trabalho tem como objetivo dar a conhecer um conjunto de achados metálicos do Bronze Final, em associação com fragmentos cerâmicos e líticos, encontrados no sítio de Moinhos de Golas, freguesia de Solveira,
concelho de Montalegre.
A coleção metálica é composta por armas, artefactos de adorno, utensílios, possíveis elementos de produção
metalúrgica, entre outros objetos de difícil classificação. As análises de composição química a peças selecionadas, embora preliminares, mostram que a maioria dos artefactos foram produzidos numa liga de bronze binário (Cu-Sn).
Pelo facto de terem sido encontradas dispersas por vários lugares do outeiro, este grupo de peças não pode
considerar-se um depósito fechado.[EN] This work aims to publish a set of metal findings attributed to Bronze Age, and found in association with ceramic and lithic fragments. These were found in the Moinhos de Golas site, Solveira parish, in the Montalegre council.
This set consists of metallic weapons, ornaments, tools, and some objects that might be related to metallurgical
processes, among other objects difficult to classify. Preliminary elemental analysis made on selected artefacts
point out that most objects were produced in a binary bronze alloy.
This set of artefacts, given their finding circumstances, should not be regarded as a closed hoard.Este trabalho foi desenvolvido no âmbito dos projetos Metalurgia Primitiva no Território Português–EARLYME-TAL(PTDC/HIST-ARQ/110442/2008) e Espaços Naturais,
Arquiteturas, Arte rupestre e Deposições na Pré-história Recente da Fachada Ocidental do Centro e Norte Português: das Ações aos Significados - ENARDAS
(PTDC/HIS-ARQ/112983/2009), financiado pelo Programa Operacional Temático Factores de Competitividade (COMPETE) e comparticipados pelo Fundo Comunitário
Europeu FEDER. Os autores agradecem à Fundação para a Ciência e a Tecnologia (FCT) as bolsas individuais (SFRH/BD/65143/2009) e (SFRH/BPD/73245/2010) concedidas a João Fonte e Elin Figueiredo, respetivamente, e o apoio financeiro concedido ao CENIMAT/I3N através do Projecto Estratégico LA25/2013-2014 (PEst-C/CTM/LA0025/2011).Peer Reviewe
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