Colonization of a 'Lost World': Encrustation patterns in modern subtropical brachiopod assemblages.

The encrustation of Paleozoic rhynchonelliform brachiopods has been studied for decades, but modern brachiopods have not received similar scrutiny. The discovery of abundant subtropical brachiopods from the Southeast Brazilian Bight provides an unprecedented opportunity to assess epibiont abundance, diversity, and encrustation patterns in modern brachiopod assemblages. Across the outer shelf, encrustation frequencies vary among taxa, from mean values of 0.45% for Platidia to 9.3% for Argyrotheca. Encrustation frequencies for Bouchardia increase from 1.6% on the outer shelf to 84% on the inner shelf Larger valves are encrusted more frequently, and epibionts preferentially colonize valve interiors. Increased encrustation on the inner shelf may reflect the greater surface area of larger hosts, longer exposure of dead shells, water-mass characteristics, sedimentation rates, productivity, or other factors that vary with depth. Inner-shelf brachiopods exhibit encrustation frequencies comparable to those reported for epifaunal bivalves. The epibiont fauna is dominated by bryozoans and serpulids, with minor roles played by spirorbids, bivalves, barnacles, foraminifera, algae, and other taxa. Epibiont abundance at each site is highly variable, but sites are similar in rank importance of epibiont taxa. A different suite of epibionts colonized Paleozoic brachiopods, but similar patterns of encrustation have been observed, including preferential settlement according to valve morphology. These results provide a baseline for evaluating the encrustation of modern bivalves and ancient brachiopods, and may elucidate the macroevolutionary history of epibionts and their relationship to their hosts.

Molecular characterization of hemoglobin alpha-D chains from Geochelone carbonaria and Geochelone denticulata land turtles

In order to help elucidate the evolution of alpha-globins, the complete cDNA and amino acid sequences of Geochelone carbonaria and Geochelone denticulata land turtles alpha-D chains have been described. In G. carbonaria, the cDNA is 539 bp with ATG start codon located at position 46, TGA stop codon at position 469 and AATAAA polyadenylation signal at position 520. In G. denticulata, the cDNA is 536 bp with ATG start codon located at position 46, TGA stop codon at position 469 and AATAAA polyadenylation signal at position 517. Both cDNAs codify 141 amino acid residues, differing from each other in only four amino acid residues. When comparing with human Hb alpha-chain, alterations in important regions can be noted: alpha110 Ala-Gly, alpha114 Pro-Gly, alpha117 Phe-Tyr and alpha122 His-Gln. There is a high homology between the amino acids of these turtles when compared with chicken alpha-D chains, progressively decreasing when compared with human, crocodile, snake, frog and fish alpha-chains. Phylogenetic analysis of alpha-D chains shows that those of turtles are closer to those of birds than to snakes and lizards. (C) 2002 Elsevier B.V. All rights reserved.

Avaliação da Gravidade Específica e de Outras Medidas Corporais e da Carcaça para Estimar a Composição Corporal de Novilhos Nelore

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Investigation of food grain drying with pulsating air flows

In this article we investigate experimentally the potential of using pulsating flows for drying of food grains. A Rijke type oscillator with an electrical heater was used to dry batches of soybean grains. Drying temperatures were 60 degreesC. We observed a decrease on the drying time for pulsating flows when compared with the conventional non-pulsating regime. This decrease depended on sample initial moisture content and weight, and on final sample moisture content. (C) 2004 Elsevier B.V. Ltd.

MORPHOLOGIC AND MORPHOMETRIC ASPECTS OF ENOCYTES OF APIS-MELLIFERA QUEENS AND WORKERS IN DIFFERENT PHASES OF LIFE

Oenocytes of adult workers and queens of Apis mellifera L. were studied in different ages or life stages, by means of morphometric and histologic techniques. In workers, the oenocytes were found in the head, near the mandibles and in the abdomen, immersed in the parietal fat body mainly below the sterna, close to the wax glands. In queens, two populations of oenocytes different in size and localization were found within the parietal and visceral fat body, respectively. The oenocytes of workers and queens show the presence of acid lipids and acid phosphatase. The role of these cells in the castes differences is discussed.

Systematic consideration of petiole anatomy of species of Echinodorus Richard (Alismataceae) from north-eastern Brazil

Petiole anatomy of the north-eastern Brazilian species Echinodorus glandulosus, E. palaefolius, E. pubescens, E subalatus, E lanceolatus and E paniculatus were examined. All species had petioles with an epidermis composed of tabular cells with thin walls. The chlorenchyma just below the epidermis alternates with collateral vascular bundles. The interior of the petiole is filled by aerenchyma with ample open spaces or lacunas. The lacunas are bridged at intervals by plates, or by diaphragm-like linkages. There are lactiferous ducts and groups of fibres throughout the entire length of the petiole, but more frequently in the chlorenchyma. Important taxonomic characteristics for the genus Echinodorus include the shape and outline of the petiole in transversal section, the presence of winged extensions, and the number of vascular bundle arcs. Exceptions occur in E. lanceolatus and E. paniculatus, whose petioles have similar anatomic patterns. A comparative chart of the petiole anatomic characteristics analyzed is presented. (c) 2007 Elsevier GmbH. All rights reserved.

DUPLICATION OF THE SHORT ARM OF THE X-CHROMOSOME IN MOTHER AND DAUGHTER

An 11-year-old girl with short stature, mental retardation, and mild dysmorphic features was found to have an inverted duplication of most of the short arm of the X chromosome [dic inv dup(X)(qter --> p22.3 = p22.3 --> cen:)]. Her mother, who is also short and retarded, carries the same duplication. Fluorescence in situ hybridization with an X chromosome library, and with X centromere-specific alpha satellite and telomere probes, was useful in characterizing the duplication. In most females with structurally abnormal X chromosomes, the abnormal chromosome is inactivated. Although the duplicated X was consistently late replicating in the mother, X chromosome inactivation studies in the proband indicated that in 11 % of her lymphocytes the duplicated X was active.

Assessment of anaerobic power of swimmers: the correlation of laboratory tests on an arm ergometer with field tests in a swimming fool

The aim of this study was to verify the correlation between the Wingate arm crank test outputs (peak power, mean power, and fatigue index), obtained on a specific ergometer, and the performance in crawl stroke swim sprints of 14, 25, 50, and 400 m. The experiment was conducted with 9 healthy male volunteers (18.1 +/- 2.2 years of age; 172 +/- 0.04 cm; 67.7 +/- 5.92 kg and 15.7 +/- 4.57% body fat). on determined days, all individuals were submitted to the Wingate arm crank test and crawl freestyle sprints of 14, 25, 50, and 400 m as they were timed with a stopwatch. The peak power, the mean power, and the fatigue index, which were obtained during the Wingate arm crank test, were not significantly correlated with the maximum swim velocities during the crawl free-style tests of 14 (r = 0.40; r = 0.64; r = 0.11), 25 (r = 0.28; r = 0.39; r = -0.27), 50 (r = 0.03; r = 0.09; r = -0.31), and 400 (r = -0.52; r = -0.37; r = -0.65) m respectively. Thus, it is possible to conclude that the Wingate arm crank test is not suitable to assess the anaerobic power of swimmers under the described experimental conditions.

Efeito de datas de semeadura no comportamento de dois genótipos de girassol. II. Aspectos nutricionais

Este experimento foi realizado em Jaboticabal, SP, como objetivo de se avaliar o comportamento de dois genótipos de girassol (Helianthus annuus L.) no tocante à composição mineral e teor de óleo. Utilizou-se o híbrido Contissol 812 e a cuttivar IAC-Anhandy com 80cm entre linhas e cinco plantas por metro linear, em blocos casualizados, com quatro repetições, em cinco datas de semeadura: 20.1; 20.2; 5.3; 20.3 e 5.4. O atraso das datas de semeadura exerceu efeito depressivo e significativo sobre a absorção (N-total 86,4 e 19,1; P = 8,3 e 1,6; K = 77,0 e 17,5; Ca =52,1 e 6,8 e Mg = 10,3 e 1,7) e a exportação (N-total = 89,6 e 27,3; P = 9,1 e 2,5; K = 30,1 e 8,8; Ca = 7,0 e 2.1 e Mg =9,7 e 2,8) de nutrientes, expressos em kg/ha, para a primeira e última data, respectivamente, nos dois genótipos que mantiveram constante (40%) o teor de óleo. Concluiu-se que os dois genótipos se comportaram de forma semelhante e que as semeaduras realizadas até o final de fevereiro foram as melhores, e nas efetuadas posteriormente a absorção total em kg/ha dos diversos nutrientes foi afetada negativamente, pelo fato de a produção de aquênios ter sido obtida em níveis indesejáveis.

Purification and properties of buffalo (Bubalus bubalis) erythrocyte hexokinase

Buffalo erythrocytes contain one isozyme of hexokinase that apparently lacks microheterogeneity as shown by chromatographic properties. A single protein band was detected by means of Western blotting using an antibody raised in rabbits against homogeneous rat brain hexokinase I. The native protein has a molecular weight of 200,000 +/- 2880 by gel filtration. Partial purification of erythrocyte hexokinase by a combination of several procedures, including affinity chromatography, which was previously applied successfully to the purifica tion of other mammalian type I hexokinases, produced a partially purified enzyme that showed several contami nants after SDS-polyacrylamide gel electrophoresis. The affinity of buffalo erythrocyte hexokinase for glucose (K-m = 0.012 +/- 0.001 mM) is lower than most other mammal hexokinases type I. It phosphorylates other sugars, with considerably higher K-m values. This isozyme is able to use MgATP but does not use MgGTP, MgCTP or MgUTP. We used inhibition patterns, obtained with products to elucidate enzyme sequential mechanisms. Our results are clearly in agreement with a random sequential mechanism and in disagreement with an ordered sequential mechanism with either glucose or ATP as the obligatory first substrates. The ADP inhibition was of mixed type with both ATP and glucose as substrates. (C) 1997 Elsevier B.V.

Exact propagator beyond and at caustics for isotropic time-dependent coupled and driven oscillators

Through a sequence of transformations we relate the propagator for the system of isotropic time-dependent, coupled and driven oscillators with time-varying mass, with those of free particles. We then derive the wave functions and the propagator beyond and at caustics. Finally we study a particular case which appears in quantum optics. © 1990.