Comparative Analyses of Age- and Sex-Specific Patterns of Vocal Behaviour in Four Species of Old World Monkeys

Sound recordings and behavioural data were collected from four primate species of two genera (Macaca, Presbytis). Comparative analyses of structural and behavioural aspects of vocal communication revealed a high degree of intrageneric similarity but striking intergeneric differences. In the two macaque species (Macaca silenus, Macaca radiata), males and females shared the major part of the repertoire. In contrast, in the two langurs (Presbytis johnii, Presbytis entellus), many calls were exclusive to adult males. Striking differences between both species groups occurred with respect to age-specific patterns of vocal behaviour. The diversity of vocal behaviour was assessed from the number of different calls used and the proportion of each call in relation to total vocal output for a given age/sex class. In Macaca, diversity decreases with the age of the vocalizer, whereas in Presbytis the age of the vocalizer and the diversity of vocal behaviour are positively correlated. A comparison of the data of the two genera does not suggest any causal relationship between group composition (e.g. multi-male vs. one-male group) and communication system. Within each genus, interspecific differences in vocal behaviour can be explained by differences in social behaviour (e.g. group cohesion, intergroup relation, mating behaviour) and functional disparities. Possible factors responsible for the pronounced intergeneric differences in vocal behaviour between Macaca and Presbytis are discussed.

Nomenclatural corrections in Mesoamerican Plantaginaceae and a new species of Tetranema from Honduras

Study of the Plantaginaceae for the Flora Mesoamericana project has resulted in five lectotypifications, a new combination in Rhodochiton, and the discovery of a new species of Tetranema from Honduras. This species, Tetranema michaelfayanum, is described here, a key to the species of Tetranema is provided, and the T. roseum complex is discussed.

A Photoelectron Spectroscopic Study Of The Interaction Of Oxygen, Nitrogen And Transition-Metals With C-60 Films

Evidence is presented for the strong interaction of oxygen and nitrogen with solid films of buckminsterfullerene based on core-level spectroscopic studies. Cr, Ni and Cu deposited on C60 films interact strongly giving rise to large changes in the C(Is) and C(2p) binding energies as well as the (2p) binding energies of the transition metals.

Characterization of oxygen free radicals generated during vanadate-stimulated NADH oxidation

The oxidation of NADH and accompanying reduction of oxygen to H2O2 stimulated by polyvanadate was markedly inhibited by SOD and cytochrome c. The presence of decavanadate, the polymeric form, is necessary for obtaining the microsomal enzyme-catalyzed activity. The accompanying activity of reduction of cytochrome c was found to be SOD-insensitive and therefore does not represent superoxide formation. The reduction of cytochrome c by vanadyl sulfate was also SOD-insensitive. In the presence of H2O2 all the forms of vanadate were able to oxidize reduced cytochrome c, which was sensitive to mannitol, tris and also catalase, indicating H202-dependent generation of hydroxyl radicals. Using ESR and spin trapping technique only hydroxyl radicals, but not superoxide anion radicals, were detected during polyvanadate-dependent NADH oxidation.

Chemical potential of oxygen for iron-rutile-ilmenite and iron-ilmenite-ulvospinel equilibria

The chemical potential of oxygen corresponding to the iron-rutile-ilmenite (IRI) and iron-ilmenite-ulvospinel (IIU) equilibria has been measured employing solid-state galvanic cells,$$Pt, Fe + TiO_2 + FeTiO_3 //(Y_2 O_3 ) ZrO_2 //Fe + FeO, Pt$$ and $${\text{Pt, Fe + FeTiO}}_{\text{3}} {\text{ + Fe}}_{\text{2}} {\text{TiO}}_{\text{4}} {\text{//(Y}}_{\text{2}} {\text{0}}_{\text{3}} {\text{) ZrO}}_{\text{2}} {\text{//Fe + FeO, Pt}}$$ in the temperature range of 875 to 1275 K and 900 to 1373 K, respectively. The cells are written such that the right-hand electrodes are positive. The electromotive force (emf) of both the cells was found to be reversible and to vary linearly with temperature over the entire range of measurement. The chemical potential of oxygen for IRI equilibrium is represented by Δμo2(IRI) = -550,724 - 29.445T + 20.374T InT(±210) J mol−1 (875 <-T<- 1184 K) = -620,260 + 369.593T - 27.716T lnT(±210) J mol−1 (1184 <-T<- 1275 K) and that for IIU equilibrium by Δμo2(IIU) = -501,800 - 49.035T + 20.374T lnT(±210) J mol−1 (900 <-T<- 1184 K) = -571,336 + 350.003T− 27.716T lnT(=−210) J mol-1 (1184 <-T<- 1373 K) The standard Gibbs energy changes for IRI and IIU equilibria have been deduced from the measured oxygen potentials. Since ilmenite contains small amounts of Ti³+ ions, a correction for the activity of FeTiO3 has been incorporated by assuming ideal mixing on each cation sublattice in the FeTiO3-Ti2O3 system. Similarly, the ulvospinel contains some Fe³+ ions and a correction for the activity of Fe2TiO4 has been included by modeling the Fe2TiO4-Fe3O4 system. The third-law analysis of the results obtained for IRI equilibrium gives ΔH 298 0 = -575 (±1.0) kJ mol-1 and for IIU equilibrium yields ΔH 298 0 = -523.7 (±0.7) kJ mol−1}. The present results suggest that Fe2+ and Ti4+ cations mix almost ideally on the octahedral site of spinel lattice in Fe2TiO4, giving rise to a configurational contribution of 2R In 2 (11.5256 J mol-1 K-1) to the entropy of Fe2TiO4.

Theoretical estimation of the effect of minor elements on the solubility of oxygen in silicon melt

The effect of fourteen minor elements (Al, As, B, Bi, C, Ga, Ge, In, N, P, Pb, S, Sb and Sn) on the solubility of oxygen in silicon melt has been estimated using a recently developed theoretical equation, with only fundamental physical parameters such as hard sphere diameter, atomic volume and molar heat of solution at infinite dilution as inputs. The results are expressed in the form of interaction parameters. Although only limited experimental data are available for comparison, the theoretical approach appears to predict the correct sign, but underestimates the magnitude of the interaction between oxygen and alloying elements. The present theoretical approach is useful in making qualitative predications on the effect of minor elements on the solubility of oxygen in silicon melt, when direct measurements are not available.

Phenology of tree species of tropical moist forest of Uttara Kannada district, Karnataka, India

Phenological observations on tree species in tropical moist forest of Uttara Kannada district (13ℴ55′ to 15ℴ31′ N lat; 74ℴ9′ to 75ℴ10′ E long) during the years 1983–1985 revealed that there exists a strong seasonality for leaf flush, leaf drop and reproduction. Young leaves were produced in the pre-monsoon dry period with a peak in February, followed by the expansion of leaves which was completed in March. Abscission of leaves occurred in the post-monsoon winter period with a peak in December. There were two peaks for flowering (December and March), while fruit ripening had a single peak in May–June, preceding the monsoon rainfall. The duration of maturation of leaves was the shortest, while that of full ripening of fruits was the longest. Mature flowers of evergreen species lasted longer than those of deciduous species; in contrast the phenophase of ripe fruits of deciduous species was longer than that of evergreen species.

Quantitation of spermatogenesis by DNA flow cytometry: Comparative study among six species of mammals

Suspensions of testicular germ cells from six species of mammals were prepared and stained for the DNA content with a fluorochrome (ethidium bromide) adopting a common technique and subjected to DNA flow cytometry. While uniform staining of the germ cells of the mouse, hamster, rat and monkey could be obtained by treating with 0.5% pepsin for 60 min followed by staining with ethidium bromide for 30 min, that of the guinea pig and rabbit required for optimal staining pepsinization for 90 min and treatment with ethidium bromide for 60 min. The procedure adopted here provided a uniform recovery of over 80% of germ cells with each one of the species tested and the cell population distributed itself according to the DNA content (expressed as C values) into 5 major classes-spermatogonia (2C), cells in S-phase, primary spermatocytes (4C), round spermatids (1C), and elongating/elongated spermatids (HC). Comparison of the DNA distribution pattern of the germ cell populations between species revealed little variation in the relative quantities of cells with 2C (8-11%), S-phase (6-9%), and 4C (6-9%) amount of DNA. Though the spermatid cell populations exhibited variations (1C:31-46%, HCI:7-20% and and HC2:11-25%) they represented the bulk of germ cells (70-80%). The overall conversion of 2C to 1C (1C:2C ratio) and meiotic transformation of 4C cells to IC (1C:4C ratio) kinetics were relatively constant between the species studied. The present study clearly demonstrates that DNA flow cytometry can be adopted with ease and assurance to quantify germ cell transformation and as such spermatogenesis by analysing a large number of samples with consistency both within and across the species barrier. Any variation from the norms in germ cell proportions observed following treatment, for e.g. hormonal stimulation or deprivation can then be ascribed due to a specific effect of the hormone/drug on single/multiple steps in germ cell transformation

Synthesis and structure of oxygen-deficient La2NiCoO5 and LaSrCo2O5 phases

The La2NiCoO5 and LaSrCo2O5 phases have been synthesized by the temperature-programmed reduction (TPR) of the parent mixed perovskites LaNi0.5Co0.5O3 and La0.5Sr0.5CoO3, respectively, under an ammonia atmosphere. While La2NiCoO5 adopts a structure similar to the vacancy-ordered La2Ni2O5, LaSrCo2O5 crystallized in a brownmillerite-like structure. The reactivity of the perovskite oxides towards reduction by ammonia and the structure of the product oxides are found to be guided by factors such as the coordination and oxidation state of the transition-metal cations.

An XPS study on oxidation states of Pt and its alloys with Co and Cr and its relevance to electroreduction of oxygen

Cathodic reduction of oxygen in fuel cells is known to be enhanced on platinum alloys in relation to the platinum metal. The higher performance of the platinum alloys is as a result of the improved oxygen-reduction kinetics on the alloys but there is hardly any increase in the electrode platinum-surface-areas for the platinum alloys as compared to the platinum metal, and thus the higher performance is solely due to the enhanced electrocatalytic activity of the alloys as compared to the platinum metal. The present X-ray photoelectron spectroscopic (XPS) study on carbon-supported Pt, Pt–Co and Pt–Co–Cr electrocatalysts suggests the presence of a relatively lower Pt-oxide content on the alloys. The X-ray powder diffraction patterns for these electrocatalysts show that while the carbon-supported platinum electrocatalyst has a face-centered cubic (fcc) phase, carbon-supported Pt–Co and Pt–Co–Cr electrocatalysts exhibit a face-centered tetragonal (fct) phase. But, Pt electrocatalyst has a lower particle-size and, hence, a higher dispersion. Previous studies have shown higher activities on the Pt-alloys than on Pt, and have attributed it to changes in the electronic and structural characteristics of Pt. These changes can be correlated with the lower oxidation-state of Pt sites, as found in this study.

Reduction of oxygen impurity at GaN/beta-Si(3)N(4)/Si interface via SiO(2) to Ga(2)O conversion by exposing of Si surface under Ga flux

The removal of native oxide from Si (1 1 1) surfaces was investigated by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectra (SIMS) depth profiles. Two different oxide removal methods, performed under ultrahigh-vacuum (UHV) conditions, were carried out and compared. The first cleaning method is thermal desorption of oxide at 900 degrees C. The second method is the deposition of metallic gallium followed by redesorption. A significant decrease in oxygen was achieved by thermal desorption at 900 degrees C under UHV conditions. By applying a subsequent Ga deposition/redesorption, a further reduction in oxygen could be achieved. We examine the merits of an alternative oxide desorption method via conversion of the stable SiO(2) surface oxide into a volatile Ca(2)O oxide by a supply of Ga metals. Furthermore, ultra thin films of pure silicon nitride buffer layer were grown on a Si (1 1 1) surface by exposing the surface to radio-frequency (RF) nitrogen plasma followed by GaN growth. The SIMS depth profile shows that the oxygen impurity can be reduced at GaN/beta-Si(3)N(4)/Si interfaces by applying a subsequent Ga deposition/redesorption. (C) 2011 Elsevier B.V. All rights reserved.