Surface-enhanced resonance Raman scattering: Single-molecule detection in a Langmuir-Blodgett monolayer

Surface-enhanced resonance Raman scattering (SERRS) is used for single-molecule detection from spatially resolved 1-mum(2) sections of a Langmuir-Blodgett (LB) monolayer deposited onto a Ag film. The target molecule, his (benzimidazo) thioperylene (BZP), is dispersed in an arachidic acid monomolecular layer containing one BZP molecule per mum(2) which is also the probing area of the Raman microscope. For concentrated samples (attomole quantities in the field of view), average SERRS, surface-enhanced fluorescence (SEF), and Raman imaging, including line mapping and global images at different temperatures, were recorded. Single-molecule SERRS spectra, obtained using an LB monolayer, present changes in bandwidth and relative intensities, highlighting the properties of single-molecule SERRS that are lost in average SERRS measurements of mixed LB monolayers obtained at the same temperatures. Also, the dilute system phenomenon of blinking is discussed with regard to results obtained from LB monolayers. The dilution process used in the single-molecule LB SERRS work is independently supported by fluorescence results obtained from very dilute solutions with monomer concentrations down to 10(-12) M.

Parameter-dependent Lyapunov functions for state-derivative feedback control in polytopic linear systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Less Conservative Control Design for Linear Systems with Polytopic Uncertainties via State-Derivative Feedback

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Herdeiros do idealismo Alemão

Acompanha-se, aqui, a pertinência do lema de Engels, que concebe o marxismo como herdeiro do idealismo alemão nas teorias de Lukács, Horkheimer e Adorno. Enquanto Lukács assenta o método marxista na vertente da filosofia hegeliana e Horkheimer assume explicitamente o legado kantiano, Adorno não se propõe a ser herdeiro, mas sim crítico do idealismo alemão.

Almost strict total positivity and a class of Hurwitz polynomials

We establish sufficient conditions for a matrix to be almost totally positive, thus extending a result of Craven and Csordas who proved that the corresponding conditions guarantee that a matrix is strictly totally positive. Then we apply our main result in order to obtain a new criteria for a real algebraic polynomial to be a Hurwitz one. The properties of the corresponding extremal Hurwitz polynomials are discussed. (C) 2004 Elsevier B.V. All rights reserved.

Maturação de sementes de aveia-preta (Avena strigosa Schreb). II. Maturidade da panícula e da espigueta

The present work aims at defining the panicle and spikelet maturity of Avena strigosa Schreb. Four experiments were carried out under field conditions during 1989 (E1 and E2) and 1990 (E3 and E4) in Botucatu county, São Paulo State, Brazil. The sowings were made in 04.19.89 (E1) and 06.18.89 (E2). Maturity of panicle was evaluated by weekly (E1) or biweekly harvests (E2) beginning at total emergence of the panicle. In E3 and E4, sowing was made in 06.04.90 and each experiment had a single harvest date (E3 = 11.01.90 and E4 = 11.07.90). After harvest, the spikelets with similar stage of development were grouped and evaluated. Based on dry matter accumulation and germination percentage of the seeds, it was observed that the maturity of the seeds in the panicle was reached at 28 and 35 days after total emergence of the panicle in the April sowing, and between 24.5 and 28 days in the June sowing. During this period a few percentage of panicles not yet yellow became all yellow, the cariopsis at semi-hard stage became hard and moisture of the seeds dropped from 32% to 12%. The maturity of the seeds in the spikelet was reached when the glumes changed their color from yellowish to yellow, the lemma and palea changed from yellow with black strips to black, the cariopsis changed from farinaceous stage to semi-hard and the moisture content of the seeds changed from 40% to 25%.

Otimização de controladores robustos de sistemas dinâmicos sujeitos a falhas estruturais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Projeto de controladores robustos para sistemas sujeitos a falhas estruturais usando realimentação estática de saída

Pós-graduação em Engenharia Elétrica - FEIS

Campos de vetores lineares reversíveis equivariantes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cohomologia de grupos e invariante algébricos

Pós-graduação em Matemática - IBILCE

Existência de soluções de inclusões diferenciais em escalas temporais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Controle de sistemas lineares incertos via realimentação derivativa utilizando Funções de Lyapunov dependentes de parâmetros

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estabilidade, desempenho e observação de estado de sistemas chaveados afins: aplicações aos conversores CC-CC

Pós-graduação em Engenharia Elétrica - FEIS

Morfologia e anatomia de Paspalum L. (Poaceae, Poales) e suas implicações taxonômicas

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Controle robusto chaveado de sistemas lineares variantes no tempo com aplicação em falhas estruturais

Pós-graduação em Engenharia Elétrica - FEIS