Cytotoxic effects of permethrin in oocytes of Rhipicephalus sanguineus (Acari: Ixodidae) fully engorged females: I. Direct or indirect action of the acaricide in germ cells?

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

Mites and leaf domatia: no evidence of mutualism in Coffea arabica plants

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

Lambda c(+), Sigma(c), and Lambda(b) hypernuclei in the quark-meson coupling model

Charmed (and bottom) hypernuclei are studied in the quark-meson coupling (QMC) model. This completes systematic studies of charmed (Lambda(c)(+), Sigma(c), Xi(c)), and Lambda(b) hypernuclei in the QMC model. Effects of the Pauli blocking due to the underlying quark structure of baryons, and the Sigma(c)N-Lambda(c)N channel coupling are phenomenologically taken into account at the hadronic level in the same way as those included for strange hypernuclei. Our results suggest that the Sigma(c)(++) and Xi(c)(+) hypernuclei are very unlikely to be formed. while the Lambda(c)(+), Xi(c)(0) and Lambda(b) hypernuclei are quite likely to be formed. For the Sigma(c)(+) hypernuclei, the formation probability is non-zero, though small. A detailed analysis is also made about the phenomenologically introduced Pauli blocking and channel coupling effects for the Sigma(c)(0) hypernuclei.

Formation of bright solitons and soliton trains in a fermion-fermion mixture by modulational instability

We employ a time- dependent mean- field- hydrodynamic model to study the generation of bright solitons in a degenerate fermion - fermion mixture in a cigar- shaped geometry using variational and numerical methods. Due to a strong Pauli- blocking repulsion among identical spin- polarized fermions at short distances there cannot be bright solitons for repulsive interspecies interactions. Employing a linear stability analysis we demonstrate the formation of stable solitons due to modulational instability of a constant-amplitude solution of the model equations for a sufficiently attractive interspecies interaction. We perform a numerical stability analysis of these solitons and also demonstrate the formation of soliton trains by jumping the effective interspecies interaction from repulsive to attractive. These fermionic solitons can be formed and studied in laboratory with present technology.

Fermionic bright soliton in a boson-fermion mixture

We use a time-dependent dynamical mean-field-hydrodynamic model to study the formation of fermionic bright solitons in a trapped degenerate Fermi gas mixed with a Bose-Einstein condensate in a quasi-one-dimensional cigar-shaped geometry. Due to a strong Pauli-blocking repulsion among spin-polarized fermions at short distances there cannot be bright fermionic solitons in the case of repulsive boson-fermion interactions. However, we demonstrate that stable bright fermionic solitons can be formed for a sufficiently attractive boson-fermion interaction in a boson-fermion mixture. We also consider the formation of fermionic solitons in the presence of a periodic axial optical-lattice potential. These solitons can be formed and studied in the laboratory with present technology.

Dynamical collapse in a degenerate binary fermion mixture using a hydrodynamic model

We use a time-dependent dynamical hydrodynamic model to study a collapse in a degenerate fermion-fermion mixture ( DFFM) of different atoms. Due to a strong Pauli-blocking repulsion among identical spin-polarized fermions at short distances, there cannot be a collapse for repulsive interspecies fermion fermion interaction. However, there can be a collapse for a sufficiently attractive interspecies fermion-fermion interaction in a DFFM of different atoms. Using a variational analysis and numerical solution of the hydrodynamic model, we study different aspects of collapse in such a DFFM initiated by a jump in the interspecies fermion-fermion interaction ( scattering length) to a large negative ( attractive) value using a Feshbach resonance. Suggestion for experiments of collapse in a DFFM of distinct atoms is made.

Bright solitons and soliton trains in a fermion-fermion mixture

We use a time-dependent dynamical mean-field-hydrodynamic model to predict and study bright solitons in a degenerate fermion-fermion mixture in a quasi-one-dimensional cigar-shaped geometry using variational and numerical methods. Due to a strong Pauli-blocking repulsion among identical spin-polarized fermions at short distances there cannot be bright solitons for repulsive interspecies fermion-fermion interactions. However, stable bright solitons can be formed for a sufficiently attractive interspecies interaction. We perform a numerical stability analysis of these solitons and also demonstrate the formation of soliton trains. These fermionic solitons can be formed and studied in laboratory with present technology.

A constraint on the x dependence of the light antiquarks ratio

We perform a careful study on the effect of the Pauli blocking to the light antiquark structure of the proton sea. We develop the formal expressions for the antiquark distributions, highlighting the role played by quark statistics and the vacuum structure. Ratios involving the antiquarks are calculated. In particular, it is found that Delta(d) over bar (x)/Delta(u) over bar (x) should be negative and x independent. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Robust tori in a double-waved Hamiltonian model

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

Effect of robust torus on the dynamical transport

In the present work, we quantify the fraction of trajectories that reach a specific region of the phase space when we vary a control parameter using two symplectic maps: one non-twist and another one twist. The two maps were studied with and without a robust torus. We compare the obtained patterns and we identify the effect of the robust torus on the dynamical transport. We show that the effect of meandering-like barriers loses importance in blocking the radial transport when the robust torus is present.

Validation of a mutant of the pore-forming toxin sticholysin-I for the construction of proteinase-activated immunotoxins

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

Temperature dependence and magnetocrystalline anisotropy studies of self-assembled L1(0)-Fe55Pt45 ferromagnetic nanocrystals

Temperature dependence and uniaxial magnetocrystalline anisotropy properties of the chemically synthesized 4 nm L1(0)-Fe55Pt45 nanoparticle assembly by a modified polyol route are reported. As-prepared nanoparticles are superparamagnetic presenting fcc structure, and annealing at 550 degrees C converts the assembly into ferromagnetic nanocrystals with large coercivity (H-C>1 T) in an L1(0) phase. Magnetic measurements showed an increasing in the ferromagnetically ordered fraction of the nanoparticles with the annealing temperature increases, and the remanence ratio, S=M-R/M-S congruent to 0.76, suggests an (111) textured film. A monotonic increase of the blocking temperature T-B, the uniaxial magnetocrystalline anisotropy constant K-U, and the coercivity H-C with increasing annealing temperature was observed. Magnetic parameters indicate an enhancement in the magnetic properties due to the improved Fe55Pt45 phase stabilizing, and the room-temperature stability parameter of 67, which indicates that the magnetization should be stable for more than ten years, makes this material suitable for ultrahigh-density magnetic recording application.(c) 2007 American Institute of Physics.

Aplicação de técnicas eletroquímicas no estudo da dissolução oxidativa da covelita (CuS) por Thiobacillus ferrooxidans

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

Imunoglobulinas e C3 no granuloma paracoccidióidico

Utilizou-se o modelo experimental de paracoccidioidomicose, em camundongos, induzida pela inoculação endovenosa de suspensão de formas cerebriformes do P. brasiliensis (cepa Bt2; 1x10(6) formas viáveis/animal), para avaliar, após 2, 4, 8, 16 e 20 semanas: 1. A presença de imunoglobulinas e C3 nos granulomas pulmonares, por imunofluorescência direta; 2. A resposta imune humoral (imunodifusão) e celular (teste do coxim plantar), e 3. A histopatologia das lesões. Os camundongos apresentaram resposta imunocelular positiva desde a 2a. semana, com depressão transitória na 16a. semana, e anticorpos desde a 4a. semana, com pico na 16a. semana. Os granulomas pulmonares foram epitelióides, com numerosos fungos e microabscesses; a extensão das lesões foi progressiva até a 16a. semana, com regressão discreta na 20a. semana. Desde a 2a. semana, houve deposição de IgG e C3 na parede dos fungos no interior dos granulomas e a presença de células IgG positivas no halo linfomononuclear periférico; estes achados foram máximos entre a 4a. e 16a. semanas. Não se detectou depósito de IgG e C3 no interstício dos granulomas. IgG e C3 parecem exercer papel precoce e importante na defesa do hospedeiro contra o P. brasiliensis, contribuindo possivelmente para a destruição dos fungos e bloqueando a difusão de antígenos para fora dos granulomas.

Estudo Comparativo de Três Diferentes Modalidades de Elisa para Medir os Anticorpos Contra o Vírus da Bronquite Infecciosa em Frangos Vacinados e Não Vacinados

No presente estudo, foram vacinados 150 frangos de corte de um dia de idade com sorotipo H120, e, após 28 dias desafiados à vacinação com o sorotipo M 41 do vírus da bronquite infecciosa das aves. da mesma forma, foram obtidos 150 soros de aves não vacinadas para a análise. Os respectivos soros foram analisados 28, 34 e 46 dias após o desafio, examinados através das técnicas de ELISA indireto (ELISA-I), Sandwich ELISA (S-ELISA) e ELISA com bloqueio de fase líquida (ELISA-BFL) e comparados com a técnica padrão de soroneutralização (SN) para efeito de cálculo da especificidade e sensibilidade relativas, bem como os valores predictivos positivos e negativos. O cálculo do coeficiente de correlação também foi empregado para a análise de concordância. Assim, os valores da correlação encontrados foram r = 0.98 entre ELISA-BFL x SNT, r = 0.79 entre S-ELISA x SNT e r = 0.74 ELISA-I x SNT. No entanto, quando comparamos as técnicas de ELISA entre si, ELISA-BFL x S-ELISA, ELISA-BFL x ELISA-I e S-ELISA x ELISA-I os valores encontrados foram r = 0.75, r = 0.69 e r = 0.79. A técnica de ELISA-BFL demonstrou melhor sensibilidade relativa que as técnicas de S-ELISA e ELISA-I, mesmo 46 dias após o desafio com a estirpe heteróloga. Entretanto, apesar das técnicas de S-ELISA e ELISA-I apresentarem especificidade realtiva superiores, a melhor correlação observada foi entre as técnicas de ELISA-BFL e a SN.