Autosomal rearrangement in Gryllus assimilis Fabricius, 1775 (Orthoptera, Gryllidae)

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

Hydroxymethylnitrofurazone:Dimethyl-beta-cyclodextrin Inclusion Complex: A Physical-Chemistry Characterization

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

Esterase patterns and phylogenetic relationships of Drosophila species in the saltans subgroup (saltans group)

The esterase patterns of sixteen strains from four species in the saltans subgroup were analyzed using polyacrylamide gel electrophoresis. Thirty-four esterase bands were detected. By using alpha and beta naphthyl acetates as substrates, they were classified in 18 alpha-esterases (they hydrolyse the alpha-naphtyl substrate), 15 beta-esterases (they hydrolyse the beta-naphtyl substrate) and 1 alpha/beta-esterase (it hydrolyses the alpha and beta-naphtyl substrates). Among the alpha-esterases, three were detected exclusively in males. Malathion, Eserine and pCMB were used as inhibitors in order to characterize biochemically the esterases. The results indicated the presence of cholinesterases, carboxylesterases and acetylesterases. The degree of mobility of the bands in the gels, their specificity to alpha and beta naphthyl acetates and the results of the inhibition tests allowed us to recognize tentatively nine genetic loci. Phylogenetic relationships among species inferred on the basis of the esterase patterns by PAUP 4.0 b8, with neighbor-joining search and a bootstrap analysis showed that, although the four species are closely related, D. septentriosaltans, D. saltans and D. austrosaltans are closer to each other than to D. prosaltans. These results showed to be consistent with phylogenetic relationships previously inferred from inversion polymorphism.

Spin reversal and magnetization jumps in ErMexMn1-xO3 perovskites (Me = Ni, Co)

The erbium-based manganite ErMnO3 has been partially substituted at the manganese site by the transition-metal elements Ni and Co. The perovskite orthorhombic structure is found from x(Ni) = 0.2-0.5 in the nickel-based solid solution ErNixMn1-xO3, while it can be extended up to x(Co) = 0.7 in the case of cobalt, provided that the synthesis is performed under oxygenation conditions to favor the presence of Co3+. Presence of different magnetic entities (i.e., Er3+, Ni2+, Co2+, Co3+, Mn3+, and Mn4+) leads to quite unusual magnetic properties, characterized by the coexistence of antiferromagnetic and ferromagnetic interactions. In ErNixMn1-xO3, a critical concentration x(crit)(Ni) = 1/3 separates two regimes: spin-canted AF interactions predominate at x < x(crit), while the ferromagnetic behavior is enhanced for x > x(crit). Spin reversal phenomena are present both in the nickel- and cobalt-based compounds. A phenomenological model based on two interacting sublattices, coupled by an antiferromagnetic exchange interaction, explains the inversion of the overall magnetic moment at low temperatures. In this model, the ferromagnetic transition-metal lattice, which orders at T-c, creates a strong local field at the erbium site, polarizing the Er moments in a direction opposite to the applied field. At low temperatures, when the contribution of the paramagnetic erbium sublattice, which varies as T-1, gets larger than the ferromagnetic contribution, the total magnetic moment changes its sign, leading to an overall ferrimagnetic state. The half-substituted compound ErCo0.50Mn0.50O3 was studied in detail, since the magnetization loops present two well-identified anomalies: an intersection of the magnetization branches at low fields, and magnetization jumps at high fields. The influence of the oxidizing conditions was studied in other compositions close to the 50/50 = Mn/Co substitution rate. These anomalies are clearly connected to the spin inversion phenomena and to the simultaneous presence of Co2+ and Co3+ magnetic moments. Dynamical aspects should be considered to well identify the high-field anomaly, since it depends on the magnetic field sweep rate. (C) 2006 Elsevier B.V. All rights reserved.

Aesthetic correction of a hypertrophic sinus frontalis: A long-term follow-up evaluation and refinement of the method

Two cases treated for hypertrophy of the frontal sinus are presented. In both patients, the excised frontal bone was inverted, and the resultant cavity was filled with either bone dust from the parietal region or Medpor. The first patient is shown with an excellent result after a follow-up period of 16 years. The second patient, who also achieved an excellent result, is presented after a follow-up period of 5 years. Using Medpor instead of bone dust resulted in the advantage that the operation could be performed with the patient under local anesthesia with sedation and prevention of an additional donor site. The use of Medpor has certain advantages over the use of hydroxyapatite, not least of which is its significant lower cost.

Settling analysis of MOS regulated current mirrors applied to micropower D/A converters

This paper provides an insight to the trade-off between settling time and power consumption in regulated current mirrors as building parts in micropower current-switching D/A converters. The regulation-loop frequency characteristic is obtained and difficulties to impose a dominant-pole condition to the resulting 2nd-order system are evaluated. Raising pole frequencies in micropower circuits, while meeting consumption requirements, is basically limited by parasitic capacitances. For such cases, an alternative is to impose a twin-pole condition in which design constraints are somewhat relieved and settling slightly improved. Relationships between pole frequencies, transistor geometry and bias are established and design guidelines for regulated current mirrors founded. By placing loop-transistors in either weak or strong inversion, small (W/L) ratios are allowed and stray capacitances reduced. Simulated waveforms suggest a good agreement with theory. The proposed approach applied to the design of a micropower current-mode D/A converter improves both simulated and experimental settling performance.

Experimental and theoretical study on the piezoelectric behavior of barium doped PZT

An experimental and theoretical study of the ferroelectric and piezoelectric behavior of PZT doped with barium is presented. Ab initio perturbed ion calculations was carried out. The properties, such as remnant polarization, coercive field and the coupling factor of the PZT at constant sintering temperature was compared with the Zr4+/Ti4+ ions dislocation energy and the lattice interaction energy. An agreement between the experimental and theoretical results, with a decrease of the interaction energy and an inversion of the energy stability from tetragonal to rhombohedral phase was observed. (C) 1999 Kluwer Academic Publishers.

Annealing effects on optical properties of natural alexandrite

Natural alexandrite (BeAl2O4:Cr3+) crystals are investigated as regards the effects of annealing on their optical properties. Optical absorption spectra are measured from the ultraviolet (190 nm) to the near infrared (900 nm), for a sample subjected to consecutive annealing processes, where time and temperature are varied. Besides this, luminescence spectra are simultaneously obtained for this sample, excited with a Kr+ laser source, tuned on an ultraviolet multi-line mode (337.5, 350.7 and 356.4 nm). We observe from absorption as well as from emission data that annealing mainly influences the distribution of Cr3+ and Fe3+ ions, located on sites of a mirror plane (C-s symmetry), which are responsible for the optical properties of alexandrite. The results obtained lead to the conclusion that annealing induces a modification of the population of Cr3+ on C-s sites as well as on sites located on an inversion plane (C-i). Annealing could improve the optical properties of this material, as regards its application as a tunable laser.

Excited state dynamics of the Ho3+ ions in holmium singly doped and holmium, praseodymium-codoped fluoride glasses

The deactivation of the two lowest excited states of Ho3+ was investigated in Ho3+ singly doped and Ho3+, Pr3+-codoped fluoride (ZBLAN) glasses. We establish that 0.1-0.3 mol % Pr3+ can efficiently deactivate the first excited (I-5(7)) state of Ho3+ while causing a small reduction of similar to 40% of the initial population of the second excited (I-5(6)) state. The net effect introduced by the Pr3+ ion deactivation of the Ho3+ ion is the fast recovery of the ground state of Ho3+. The Burshstein model parameters relevant to the Ho3+-> Pr3+ energy transfer processes were determined using a least squares fit to the measured luminescence decay. The energy transfer upconversion and cross relaxation parameters for 1948, 1151, and 532 nm excitations of singly Ho3+-doped ZBLAN were determined. Using the energy transfer rate parameters we determine from the measured luminescence, a rate equation model for 650 nm excitation of Ho3+-doped and Ho3+, Pr3+-doped ZBLAN glasses was developed. The rate equations were solved numerically and the population inversion between the I-5(6) and the I-5(7) excited states of Ho3+ was calculated to examine the beneficial effects on the gain associated with Pr3+ codoping. (c) 2007 American Institute of Physics.

DIFFERENTIATION OF DROSOPHILA-SERIDO (ISOFEMALE LINE A95F3) AND D-KOEPFERAE (ISOFEMALE LINE B20D2) - REPRODUCTIVE ISOLATION, DEVELOPMENT TIME AND POLYTENE CHROMOSOME-BANDING PATTERNS

Drosophila serido is considered to be a superspecies consisting of two species: D. serido, from Brazil and D. koepferae from Argentina and Bolivia. However this probably does not express the entire evolutionary complexity of its populations. Isofemale lines A95F3 (from Brazil) and B20D2 (from Argentina), at present representing, respectively, the first and second species, were analyzed for fertility and fecundity in pair-mating intracrosses and intercrosses, as well as for development time, banding patterns and asynapsis of polytene chromosomes in the isofemale lines and their hybrids.Although variations in experimental conditions resulted in some variability in the results, in general A95F3 fertility and fecundity were lower than in B20D2. Intercrosses of A95F3 females and B20D2 males showed lower fertility and fecundity than the reciprocal crosses, following more closely characteristics of the mother strains. This is in contrast to the results obtained by Fontdevilla et al. (An. Entomol. Soc. Amer. 81: 380-385, 1988) and may be due to the different geographic origin of D. serido strains they used in crosses to B20D2. This difference and others cited in the literature relative to aedeagus morphology, karyotype characteristics, inversion polymorphisms and reproductive isolation strongly indicate that A95F3 and D. serido from the State of Bahia, Brazil are not a single evolutionary entity, reinforcing the idea of greater complexity of the superspecies D. serido than is known today.The reproductive isolation mechanisms found operating between A95F3 and B20D2 were prezygotic and postzygotic, the latter included mortality at the larvae stage in both directions of crosses and sterility of male hybrids in intercrosses involving B20D2 females and A95F3 males. The two isofemale lines differed in egg-adult development time, which was also differently affected by culture medium composition.A95F3 and B20D2 also showed differences in the banding patterns of proximal regions of polytene chromosomes 2, 3 and X, a fixed inversion in chromosome 3 (here named 3t), apparently not described previously, and a high degree of asynapsis in hybrids.These observations, especially those related to reproductive isolation and chromosomal differentiation (including the karyotype, previously described, and the differentiation of banding patterns, described in this paper), as well as the extensive asynapsis observed in hybrids reinforces the distinct species status of A95F3 and B20D2 isofemale lines.

POPULATIONAL STUDY OF CHROMOSOME POLYMORPHISM IN ZONOTRICHIA-CAPENSIS (EMBERIZIDAE, PASSERIFORMES, AVES)

The karyotypes of 328 specimens of Zonotrichia capensis from four regions, three in the state of Parana and one in the state of São Paulo (Brazil), were studied. This species presents a chromosomal polymorphism due to pericentric inversion, involving the 3rd and 5th chromosome pairs. Chromosome 3 exists in the 3st and 3sm conditions and chromosome 5, in 5st and 5m conditions. Mitotic metaphase spreads were obtained from bone-marrow material of colchicine-treated animals.At all collection sites the frequency of chromosome 5m was considerably lower than that of the inverted chromosome 3sm.The present work tried to establish a correlation between the frequencies of the 3rd and 5th chromosome pairs with the climatical and geographical parameters at the collecting regions.Data show that the frequency of chromosome 5m is higher in regions with low temperature and high altitude.

EU-3+ AND GD-3+ SPECTROSCOPY IN FLUOROINDATE GLASSES

Luminescence data for Eu3+ and Gd3+ in fluoroindate glasses are compared to those of a fluorozirconate glass. Emission is observed from Eu3+ 5D(J) (J = 0, 1, 2 and 3) and Gd3+ P-6(7/2) excited-state levels and the results put in evidence Eu-Eu and Gd-Eu energy transfer processes. Vibronic bands related to a 320 cm-1 vibrational mode could be observed for Eu3+ luminescent transitions with DELTAJ = 0, 1 and 2 and also for the P-6(7/2) --> S-8(7/2) transition of Gd3+. Lanthanide ion site symmetry is closer to an inversion center in fluoroindate glasses than it is in fluorozirconate.

Chromosomal studies on five species of the genus Leptodactylus Fitzinger, 1826 (Amphibia, Anura) using differential staining

Cytogenetic studies were carried out on five species of Leptodactylus, namely L. fuscus, L, notoaktites, L. labyrinthicus, L. ocellatus, and L. podicipinus, after standard staining, Ag-NOR and C-banding as well as BrdU incorporation for three of them. The species had 2n = 22 chromosomes and two basic karyotype patterns. Chromosome 8 was a marker bearing a secondary constriction. In all species, this secondary constriction corresponded to the Ag-NOR site. The species had centromeric C-bands in all chromosomes of the complement, but some interstitial or telomeric bands seemed to differentiate some karyotypes, either at the species or the population level. In L. ocellatus, the C-banding pattern confirmed the occurrence of a heteromorphic pericentric inversion in chromosome 8 in specimens from one of the populations. The BrdU incorporation technique showed no detectable difference in the replication patterns of the major bands in the chromosomes of L. noroaktites, L. labyrinthicus, and L. ocellatus.

Role of the surface state and structural feature in the thermoreversible sol-gel transition of a zirconyl aqueous precursor modified by sulfuric acid

The sols produced by admixture of ZrOCl2 acidified solutions to hot H2SO4 aqueous solutions were studied to clarify the effects of Cl- and SO42- ions on the kinetic stability of nanoparticles and to obtain some new evidence concerning the mechanism of a thermoreversible sol-gel transition observed in this system. The study of suspensions prepared with different molar ratios R-S = [Zr]/[SO42-] and R-Cl = [Zr]/[Cl-] revealed domains of composition of formation of thermoreversible gels, thermostable sols, and powder precipitation. The effects of R-S and R-Cl on the structural features of nanoparticles and on the particle solution interface were systematically analyzed for samples of thermoreversible and thermostable sol domains. Small-angle X-ray scattering measurements revealed the presence of small fractal aggregates in all samples of thermoreversible domains, while compact packing aggregates of primary particles are present in the thermostable sol. Extended X-ray absorption fine structure and elemental chemical analysis revealed that irrespective of the nominal value of R-S and R-Cl all studied samples of the thermoreversible domain are constituted by a well-defined compound possessing an inner core made of hydroxyl and oxo groups bridging together zirconium atoms surrounded on the surface by complexing sulfate ligands. zeta potentials of powders extracted by freeze-drying from the thermoreversible gel revealed a point of surface charge inversion attributed to the specific adsorption of SO42- ion. Thermoreversible gel formation is rationalized by considering the effect of the specific adsorption on the electrical double-layer repulsion together with the temperature dependency of the physical chemical properties of ions in solution.

Supersymmetric and shape-invariant generalization for nonresonant and intensity-dependent Jaynes-Cummings systems

A class of shape-invariant bound-state problems which represent transitions in a two-level system introduced earlier are generalized to include arbitrary energy splittings between the two levels as well as intensity-dependent interactions. We show that the coupled-channel Hamiltonians obtained correspond to the generalizations of the nonresonant and intensity-dependent Jaynes-Cummings Hamiltonians, widely used in quantized theories of lasers. In this general context, we determine the eigenstates, eigenvalues, the time evolution matrix and the population inversion matrix factor.