pH-cycling Model to Verify the Efficacy of Fluoride-releasing Materials in Enamel Demineralization

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Radiopacity of Portland Cement Associated With Different Radiopacifying Agents

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Variance dispersion graphs for comparing blocked response surface designs

In this paper, we extend the use of the variance dispersion graph (VDG) to experiments in which the response surface (RS) design must be blocked. Through several examples we evaluate the prediction performances of RS designs in non-orthogonal block designs compared with the equivalent unblocked designs and orthogonally blocked designs. These examples illustrate that good prediction performance of designs in small blocks can be expected in practice. Most importantly, we show that the allocation of the treatment set to blocks can seriously affect the prediction properties of designs; thus, much care is needed in performing this allocation.

Sex ratio and dynamic behavior in populations of the exotic blowfly Chrysomya albiceps (Diptera, Calliphoridae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of potassium nutrition and the nitrate ammonium ratio on the putrescine and spermidine contents in banana vitroplants

Potassium (K) is required in high doses by the banana (Musa sp.) plant and interacts with other nutrient elements in which banana tissues are maintained under in vitro condition as a consequence modifications in the plant metabolism take place mainly in nitrogen (N) compounds, such as proteins, amino acids, and secondary compounds. When K is present in concentrations lower than that required, diamines such as putrescine and poliamines are formed. This metabolic disorder can also be correlated with the presence of different inorganic N forms, such as nitrate (NO3) and ammonium (NH4), and the ratios between both ions as well. In order to follow the physiological performance of the interrelationships, K/putrescine and of the NO3/NH4 ratio in the tissue of banana vitroplantlets, shoot apex of two banana cvs. Nanica and Prata Ana were maintained in modified MS medium in the presence of six different doses of K: 5, 10, 15, 20, 25, and 30 mM. After the period of tissue proliferation the cultures were transferred to rooting media containing the same different K doses. Dry matter, K, putrescine, and spermidine contents and their accumulation were determined in the shoots and roots of the vitroplantlets and in the shoot apex of the explant donor cultivar as well as the corresponding values for the whole vitroplantlets calculated. The data were statistically analyzed. The contents and accumulations of putrescine and spermidine in banana tissues were enhanced as K concentration decreased in the medium: four times (0.19% of the dry matter) for cv. Nanica and eight times (0.25% of the dry matter) for cv. Prata Ana. This behavior was not only related to the K depletion but to the NO3/NH4 ratio as well.

Population dynamics, sex ratio and size at sex change in a protandric simultaneous hermaphrodite, the spiny shrimp Exhippolysmata oplophoroides

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

Effect of C/N Ratio and Physicochemical Conditions on the production of Rhamnolipids by Pseudomonas Aeruginosa LBI

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Phenology, sex ratio, and spatial distribution among dioecious species of Trichilia (Meliaceae)

The flowering, sex ratio, and spatial distribution of four dioecious species of Trichilia (Meliaceae) were studied in a semi-deciduous forest in southeastern Brazil. All reproductive trees (T. clausseni, T. pallida and T. catigua) with dbh greater than or equal to5 cm within a 1-ha plot were collected, sexed, mapped and, for individuals of each species, the distances to the nearest neighbour of the same and opposite sex were measured. For the shrub species T elegans (dbh <5 cm), all reproductive individuals were sampled randomly in 10 samples of 10 x 10 m. The reproductive phenology was observed at weekly to monthly intervals from May 1988 to January 1990. The species are strictly dioecious, did not present any sex-mixed trees or sex switching during the study, and sex ratio did not differ significantly from 1:1. The size distributions and the relative size variation were not significantly different. between sexes. There was no significant segregation or clumping between individuals of either sex and no fruit production without pollination. Onset of flowering and flowering peak were synchronous between male and female plants for all species studied. Flower synchrony was related to outcrossing and pollinator attraction rather than climatic factors.

Catch-per-unit-effort: which estimator is best?

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Copy number of P elements, KP/full-sized P element ratio and their relationships with environmental factors in Brazilian Drosophila melanogaster populations

The P transposable element copy numbers and the KP/full-sized P element ratios were determined in eight Brazilian strains of Drosophila melanogaster. Strains from tropical regions showed lower overall P element copy numbers than did strains from temperate regions. Variable numbers of full-sized and defective elements were detected, but the full-sized P and KP elements were the predominant classes of elements in all strains. The full-sized P and KP element ratios were calculated and compared with latitude. The northernmost and southernmost Brazilian strains showed fewer full-sized elements than KP elements per genome, and the strains from less extreme latitudes had many more full-sized P than KP elements. However, no clinal variation was observed. Strains from different localities, previously classified as having P cytotype, displayed a higher or a lower proportion of KP elements than of full-sized P elements, as well as an equal number of the two element types, showing that the same phenotype may be produced by different underlying genomic components of the P-M system.

Natural history of Peucetia flava (Araneae, Oxyopidae): seasonal density fluctuation, phenology and sex ratio on the glandular plant Rhyncanthera dichotoma (Melastomataceae)

The seasonal density fluctuation, phenology and sex ratio of Peucetia flava (Oxyopidae) on Rhyncanthera dichotoma (Melastomataceae) were investigated during a year in a swamp in southeastern Brazil. Peucetia flava displayed an unusual non-seasonal life cycle and the population size varied little over the year. The density of Peucetia spiders increased with the increase in abundance of leaves and number of arthropods adhered to glandular trichomes on R. dichotoma leaves. Our findings suggest that seasonal density fluctuation of Peucetia may be influenced by foraging site availability (i.e. leaves) and prey supply (i.e. arthropods adhering to glandular trichomes). The unusual seasonal stability of P. flava may be related to the type of habitat in which this spider occurs (swamp), because of the constant input of allochthonous resources from the water source, i.e. aquatic insects that migrate to the terrestrial environment.

Measurement of the ratio of B+ and B-0 meson lifetimes

The ratio of the B+ and B-0 meson lifetimes was measured using data collected in 2002-2004 by the D0 experiment in Run II of the Fermilab Tevatron Collider. These mesons were reconstructed in B&RARR;μ(+)ν D*-X decays, which are dominated by B-0 and B&RARR;μ(+)ν(D) over bar X-0 decays, which are dominated by B+. The ratio of lifetimes is measured to be τ(+)/τ(0)=1.080&PLUSMN; 0.016(stat)&PLUSMN; 0.014(syst).

Theory of small aspect ratio waves in deep water

In the limit of small values of the aspect ratio parameter (or wave steepness) which measures the amplitude of a surface wave in units of its wave-length, a model equation is derived from the Euler system in infinite depth (deep water) without potential flow assumption. The resulting equation is shown to sustain periodic waves which on the one side tend to the proper linear limit at small amplitudes, on the other side possess a threshold amplitude where wave crest peaking is achieved. An explicit expression of the crest angle at wave breaking is found in terms of the wave velocity. By numerical simulations, stable soliton-like solutions (experiencing elastic interactions) propagate in a given velocities range on the edge of which they tend to the peakon solution. (c) 2005 Elsevier B.V. All rights reserved.

Measurement of the ratio of inclusive cross sections sigma(p(p)over-bar -> Z plus b jet)/sigma(p(p)over-bar -> Z plus jet) at root s=1.96 TeV

Using the data collected with the D0 detector at root s=1.96 TeV, for integrated luminosities of about 180 pb(-1), we have measured the ratio of inclusive cross sections for p(p) over bar -> Z+b jet to p(p) over bar -> Z+jet production. The inclusive Z+b-jet reaction is an important background to searches for the Higgs boson in associated ZH production at the Fermilab Tevatron collider. Our measurement is the first of its kind, and relies on the Z -> e(+)e(-) and Z ->mu(+)mu(-) modes. The combined measurement of the ratio yields 0.021 +/- 0.005 for hadronic jets with transverse momenta p(T)> 20 GeV/c and pseudorapidities vertical bar eta vertical bar < 2.5, consistent with next-to-leading-order predictions of the standard model.

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.