The Be star 59 Cyg was directly confirmed to be an evolved Be binary with a sdO companion (Be + sdO) by a weak HeII 4686 absorption. Orbital elements and stellar masses were determined. The orbital period was found to be 28.192 ± 0.004 d with a slightly eccentric orbit of e = 0.11 ± 0.005. The mass of the secondary is located in the range between 1.56 and 2.3 M Ø. Thus, 59 Cyg most likely resembles the well known Be + sdO binary φ Per in an earlier stage. Characteristic features for Be binaries with sdO or white dwarf companions were identified. They can be used for an easier identification of further evolved Be binaries or candidate systems.
Leaf tissue damaging to seedlings can limit their subsequent growth, and the effects may be more extensive. Compensatory photosynthesis responses of the remnant cotyledon and primary leaf of Pharbitis purpurea to clipping and the effect of clipping on seedling growth were evaluated in a pot-cultivated experiment. Three treatments were conducted in the experiment, which were clipped cotyledon (CC), clipped second leaf (CL), and control group (CG). The area, thickness, mass, and longevity of the remaining cotyledon of CC exhibited over-compensatory growth. In contrast, seedlings of CC had under-compensatory growth in seedling height, root length, seedling mass, and root to shoot ratio. However, the traits of remnant cotyledon and seedling in CL treatment exhibited equal-compensatory growth. Net photosynthetic rate of the cotyledon of CC was significantly higher than those of CL and CG treatments, and the diurnal changes in photosynthetic rates showed significantly different patterns which were unimodal curve (CC) and bimodal curve (CL and CG), respectively. There was no significant difference between CL and CG treatment. Net photosynthetic rate of the primary leaf of CL was significantly higher than that of CG treatment. However, the photosynthetic rates of primary leaves of CL and CG treatments showed similar photosynthetic patterns characterized by a bimodal curve. P. purpurea seedlings used a compensatory growth strategy in the remaining cotyledon or the primary leaf to resist leaf loss and minimize any adverse effects. and W. Zheng ... [et al.].
The dynamical evolution of short-period comets, and in particular of those belonging to the so-called Jupiter family, is reviewed. Encounters with Jupiter play a dominant role in determining the
dynamical fate of these objects, although, in some peculiar cases, also interactions with other planets may be important. Frequent although temporary librations around resonances with Jupiter are displayed by more than one third of short-period comets. Integrations of motion of observed comets, over a time span comparable with their lifetime as active objects, are compared with previous numerical investigations, to get insight into the non observed phases of the dynamical evolution of these objects.
Three species of cichlid fish, Tilapia brevimanus Boulenger, 1911, T. buttikoferi (Hubrecht, 1881), and T. cessiana Thys van den Audenaerde, 1968, from Guinea, Ivory Coast and Sierra Leone (West Africa) were examined for gill parasites for the first time. Six species of Monogenea were found of which one, Cichlidogyrus digitatus Dossou, 1982, had been previously described. Five new species, all belonging to the genus Cichlidogyrus Papema, 1960, are described herein: C. albareli sp. n., C. hemi sp. n., C. nuniezi sp. n„ C. honhommei sp. n., and C. slembroucki sp.n.
The actívities of glycine oxidase (GO) and serine dehydratase (SD) were revealed in green leaves of wheat and maize. The enzymes were extracted by ammonium sulfáte fractionation. GO localized in chloroplast and cytosolic fraction was most active at pH 8.0. Its activity was 1.5-2.0 times higher in wheat than in maize and it declined with leaf aging. The enzyme converts glycine into glycollate and ammonium ion being flavine dependent and generating H2O2. We propose that it is an L-amino-acid oxidase (EC 1.4.3.2) with a higher specificity to glycine. The activity of SD (EC 4.2.1.13) localized in chloroplasts was maximum at pH 7.0-7.2, it was also higher in wheat than in maize. Pyruvate was determined as a product of enzymatic conversion of L-serine. SD and GO actívities were not revealed in etíolated leaves.
Gyrodactylus orecchiae sp. n. (Monogenea, Gyrodactylidae) is described from the skin, fins, eyes and gills of juvenile Sparus aurata L. (gilthead seabream) following two outbreaks of gyrodactylosis amongst stocks held in inshore floating cages on the Adriatic coast of Albania and Croatia. Fish were heavily infected (1000+ gyrodactylids/fish) with G. orecchiae which reportedly resulted in ~2-10% mortality amongst the infected stock. Morphologically, the haptoral hooks of G. orecchiae most closely resemble those of Gyrodactylus arcuatus Bychowsky, 1933 in the approximate shape of the ventral bar with its pronounced ventral bar processes and marginal hook sickles which possess a square line to the inner edge of the sickle blade and large rounded heels. The marginal hooks are also morphologically similar to those of Gyrodactylus quadratidigitus Longshaw, Pursglove et Shinn, 2003 and Gyrodactylus colemanensis Mizelle et Kritsky, 1967, but G. orecchiae can be readily discriminated from all three species by the characteristic infolding of the hamuli roots and the shape of the marginal hook sickle. Molecular sequencing of the ITS1, 5.8S, ITS2 regions (513+157+404 bp, respectively) of G. orecchiae and alignment with other gyrodactylids for which these same genomic regions have been determined, suggests that this is a new species. No similarities were found when the ITS1 region of G. orecchiae was compared with 84 species of Gyrodactylus available on GenBank.
The most frequently used instrument for measuring velocity distribution in the cross-section of small rivers is the propeller-type current meter. Output of measuring using this instrument is point data of a tiny bulk. Spatial interpolation of measured data should produce a dense velocity profile, which is not available from the measuring itself. This paper describes the preparation of interpolation models. Measuring campaign was realized to obtain operational data. It took place on real streams with different velocity distributions. Seven data sets were obtained from four cross-sections varying in the number of measuring points, 24-82. Following methods of interpolation of the data were used in the same context: methods of geometric interpolation arithmetic mean and inverse distance weighted, the method of fitting the trend to the data thin-plate spline and the geostatistical method of ordinary kriging. Calibration of interpolation models carried out in the computational program Scilab is presented. The models were tested with error criteria by cross-validation. Ordinary kriging was proposed to be the most suitable interpolation method, giving the lowest values of used error criteria among the rest of the interpolation methods.