Habits hidden underground: a review on the reproduction of the Amphisbaenia with notes on four neotropical species

We review the information currently available on the reproduction of the Amphisbaenia and provide original data on the reproductive biology of four Neotropical species: Amphisbaena alba; A. mertensi; Cercolophia roberti, and Leposternon infraorbitale. In total, we compiled data for 22 species: 17 Amphisbaenidae, 1 Rhineuridae, 3 Bipedidae, and 1 Trogonophidae. The majority of the species were oviparous with the exceptions of Loveridgea ionidesii, Monopeltis anchietae, M. capensis, and Trogonophis wiegmanni. Viviparity was interpreted as a derived trait that evolved independently for at least 3 times within the Amphisbaenia. In most species, reproduction is synchronized with the hot and rainy season and seems to vary with latitude. Although Amphisbaenia eggs have been found in ant nests, it remains disputable whether this is an obligatory or even a preferable location for egg-laying. Incubation time in A. mertensii lasts 59 days and this is the first report encompassing egg-laying to hatching for any Amphisbaenia species. Nonetheless, a two months incubation period seems to be the common rule for oviparous Amphisbaenia. The general pattern of reproductive output in Amphisbaenia is characterized by a low number of eggs/embryos per clutch whose individual size is comparatively large in relation to adult body size. Eggs are markedly elongated on the long axis and arranged in-line within the abdominal cavity possibly to prevent/diminish biomechanic drawbacks of egg bearing. Hatchlings of A. mertensi possess an egg-tooth implanted at the upper jaw, exhibit positive geotropism, and display defensive behaviors known to be present in adults. Our review shows that our current knowledge of Amphisbaenia reproduction is fragmentary, often based on the examination of small samples, and heavily dependent on the publication of anedoctal observations. Future publications on this subject are encouraged.

Fish, Mogi Guacu reservoir and four oxbow lakes, state of São Paulo, Brazil.

The Mogi Guacu River is one of the largest rivers in state of São Paulo, belonging to Parana hydrographic system. A study about fish composition in the Mogi Guacu reservoir and four oxbow lakes downstream the reservoir is showed. A total of 2,367 individuals from six orders, 17 families, and 46 species were collected during August 2005 to July 2006, using gillnets, traps and hand nets. In the reservoir were found 31 species and in the oxbow lakes 24, in which Curimatidae and Characidae were the most abundant families, respectively.

Esterase patterns in four Brazilian populations of Haematobia irritans

Four population samples of Haematobia irritans (horn flies), collected from farms and subjected, or not, to insecticide control, were: analysed as to esterase bands by polyacrylamide gel electrophoresis. Eight esterase bands were detected in this species, a low number when compared with flies of other genera. The reduced number of esterase variants of H. irritans is attributed to their parasitic behaviour and blood-dependence for food. Unlike other fly species whose esterase bands exhibit affinity to both alpha- and beta-naphthyl acetates, the esterases in H. irritans seem to be of a single kind, all preferentially hydrolysing a-naphthyl. The four populations were very similar as to esterase bands. In relation to the frequencies of patterns resulting from combining bands, Nova Alianca and Birigui were more alike than the other two populations. Inhibitors were used in an attempt to classify five of the esterase bands. The results indicate one acetylcholinesterase, two acetylesterases and two carboxylesterases.

Chromosomal location of heterochromatin and 45S rDNA sites in four South American triatomines (Heteroptera: Reduviidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Visceral pigmentation in four Dendropsophus species (Anura: Hylidae): Occurrence and comparison

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

Nucleolar behaviour during meiosis in four species of phyllostomid bats (Chiroptera, Mammalia)

We analyzed the behavior of the nucleolus, nucleolar structures and nucleolus organizer regions (NORs) during meiotic division in four species of phyllostomid bats that have different numbers and locations of NORs. Nucleoli began disassembly at leptotene, and the subcomponents released from the nucleolus were dispersed in the nucleoplasm, associated with perichromosomal regions, or they remained associated with NORs throughout division. In Phyllostomus discolor, a delay in nucleolus disassembly was observed; it disassembled by the end of pachytene. The RNA complexes identiied by acridine orange staining were observed dispersed in the nucleoplasm and associated with perichromosomal regions. FISH with rDNA probe revealed the number of NORs of the species: one NOR in Carollia per spicillata, one pair in Platyrrhinus lineatus and P. discolor, and three pairs in Artibeus lituratus. During pachytene, there was a temporary dissociation of the homologous NORs, which returned to pairing at diplotene. The variation in the number (from one to three pairs) and location of NORs (in sex or autosomal chromosomes, at terminal or interstitial regions) did not seem to interfere with the nucleolar behavior of the different species because no variation in nucleolar behavior that could be correlated with the variation in the number and chromosomal location of NORs was detected.

Evaluation of the Naturally Acquired Antibody Immune Response to the Pv200L N-terminal Fragment of Plasmodium vivax Merozoite Surface Protein-1 in Four Areas of the Amazon Region of Brazil

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

Structure and composition of the stream ichthyofauna of four tributary rivers of the upper Rio Parana basin, Brazil

The ichthyofauna of 24 stretches of streams, all of 100 m length and of fifth or lower order and most of second and third order, were sampled along four left bank tributaries (Rio do Peixe, Rio Aguapei, Rio Sao Jose dos Dourados, lower Rio Tiete of the main channel of the Rio Parana in the state of São Paulo, southeastern Brazil. Sampling of the fish fauna at each of the six sites in the four basins incorporated a standardized fish collecting methodology and a standardized documentation of environmental data serving as the basis for a comparative analysis of the collecting locations. The 8,189 fish specimens collected represented six orders, 18 families, 42 genera, and 56 species, with a total biomass of 28.8 kg. Approximately 52% of the collected species were characiforms, 28% siluriforms, 9% gymnotiforms, 5% cyprinodontiforms, 4% perciforms, and 2% synbranchiforms. The most abundant of the species were the characiforms Astyanax altiparanae (15% of total) and Knodus moenkhausii (12% of total). The two species with the largest overall biomasses were A. altiparanae (34% of total biomass) and the siluriform Hypostomus sp. (8% of total biomass). Analysis of the trophic structure of the studied ichthyofauna indicated that the 10 numerically dominant species across the 24 sampled streams can be grouped into five guilds that are in decreasing order of numerical importance: omnivores, insectivores, insectivores/invertivores, periphytivores, and algivores. Species richness in the sampled stream stretches varied from six to 20 species with an average richness of 14. The species richness estimated by extrapolation for all 24 sampled stream stretches was 67 species. The Characidae are predominant among the collected specimens with approximately 50% of both individuals and biomass, a fact hypothesized to be a function of several attributes typical of the family. Six of the 56 collected species were new to science and six other species are of indefinite taxonomic status and require further analysis in order to determine their identity.

Flexural Strength of Four Adhesive Fixed Dental Prostheses of Composite Resin Reinforced with Glass Fiber

Purpose: To evaluate the flexural strength of two fixed dental prosthesis (FDP) designs simulating frameworks of adhesive fixed partial prostheses, reinforced or not by glass fiber.Materials and Methods: Forty specimens, made with composite resin, were divided into 4 groups according to the framework design and the presence of fiber reinforcement: A1 - occlusal support; A2: occlusal support + glass fiber; B1: occlusal and proximal supports; B2: occlusal and proximal supports + glass fiber. The specimens were subjected to the three-point bending test, and the data were submitted to two-way ANOVA and Tukey's test (5%).Results: Group A2 (97.9 +/- 38 N) was statistically significantly different from all other experimental groups, presenting a significantly lower mean flexural strength.Conclusion: The use of glass fibers did not improve the flexural strength of composite resin, and designs with occlusal and proximal supports presented better results than designs simulating only occlusal support.

Surface roughness of enamel and four resin composites

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Four-boson scale near a Feshbach resonance

We show that an independent four-body momentum scale mu((4)) drives the tetramer binding energy for fixed trimer energy (or three-body scale mu((3))) and large scattering length (a). The three- and four-body forces from the one-channel reduction of the atomic interaction near a Feshbach resonance disentangle mu((4)) and mu((3)). The four-body independent scale is also manifested through a family of Tjon lines, with slope given by mu((4))/mu((3)) for a(-1) = 0. There is the possibility of a new renormalization group limit cycle due to the new scale.

Cutoff-independent regularization of four-fermion interactions for color superconductivity

We implement a cutoff-independent regularization of four-fermion interactions to calculate the color-superconducting gap parameter in quark matter. The traditional cutoff regularization has difficulties for chemical potentials mu of the order of the cutoff Lambda, predicting in particular a vanishing gap at mu similar to Lambda. The proposed cutoff-independent regularization predicts a finite gap at high densities and indicates a smooth matching with the weak coupling QCD prediction for the gap at asymptotically high densities.

Four-point amplitude from open superstring field theory

An open superstring field theory action has been proposed which does not suffer from contact term divergences. In this paper, we compute the on-shell four-point tree amplitude fi om this action using the Giddings map. After including contributions from the quartic term in the action, the resulting amplitude agrees with the first-quantized prescription. (C) 2000 Elsevier B.V. B.V. All rights reserved.

Is the equivalence for the response of static scalar sources in the Schwarzschild and Rindler spacetimes valid only in four dimensions?

It was shown recently that in four dimensions scalar sources with fixed proper acceleration minimally coupled to a massless Klein-Gordon field lead to the same responses when they are (i) uniformly accelerated in Minkowski spacetime (in the inertial vacuum) and (ii) static in the Schwarzschild spacetime (in the Unruh vacuum). Here we show that this equivalence is broken if the spacetime dimension is more than four.

Many-body system with a four-parameter family of point interactions in one dimension

We consider a four-parameter family of point interactions in one dimension. This family is a generalization of the usual delta-function potential. We examine a system consisting of many particles of equal masses that are interacting pairwise through such a generalized point interaction. We follow McGuire who obtained exact solutions for the system when the interaction is the delta-function potential. We find exact bound states with the four-parameter family. For the scattering problem, however, we have not been so successful. This is because, as we point out, the condition of no diffraction that is crucial in McGuire's method is nor satisfied except when the four-parameter family is essentially reduced to the delta-function potential.