High resolution satellite imagery and GPS collars can help assist in the assessment of patch selection by grazing cattle in semi-arid savannas.

The selection of different patch types for grazing by cattle in tropical savannas is well documented. Advances in high resolution satellite imagery and computing power now allow us to identify patch types over an entire paddock, combined with GPS collars as a non instrusive method of capturing positional data, an accurate and comprehensive picture of landscape use by cattle can be quantified.

Patch selection by cattle can be quantified using satellite imagery and GPS in extensive, semi-arid savannas.

Patch selection by grazing animals is difficult to quantify, particularly in large, extensive paddocks like those in northern Australia. However, advances in high resolution satellite imagery now allow identification of patch types over an entire paddock which combined with GPS collars to capture positional data, can give an accurate and comprehensive picture of landscape use by cattle.

Doping Dependence of Semiconductor-Metal Transition in InP at High Pressures

The resistivity of selenium-doped n-InP single crystal layers grown by liquid-phase epitaxy with electron concentrations varying from 6.7 x 10$^18$ to 1.8 x 10$^20$ cm$^{-3}$ has been measured as a function of hydrostatic pressure up to 10 GPa. Semiconductor-metal transitions were observed in each case with a change in resistivity by two to three orders of magnitude. The transition pressure p$_c$ decreased monotonically from 7.24 to 5.90 GPa with increasing doping concentration n according to the relation $p_c = p_o [1 - k(n/n_m)^a]$, where n$_m$ is the concentration (per cubic centimetre) of phosphorus donor sites in InP atoms, p$_o$ is the transition pressure at low doping concentrations, k is a constant and $\alpha$ is an exponent found experimentally to be 0.637. The decrease in p$_c$ is considered to be due to increasing internal stress developed at high concentrations of ionized donors. The high-pressure metallic phase had a resistivity (2.02-6.47) x 10$^{-7}$ $\Omega$ cm, with a positive temperature coefficient dependent on doping.

Auger studies of transition metal oxides

Intra-atomic Auger transitions involving metal energy levels are found to be useful in studying the surface oxidation state as well as the oxidation of metals. Transition Metal oxides also exhibit interatomic Auger transitions, the intensities of which depend on the occupation of the metal d level. The probability of the interatomic transition is therefore highest in oxides where the metal has the d' configuration. The competition between intra-atomic and interatomic Auger transitions in oxides will be discussed as also the use of the interatomic transitions in the study of metal oxidation.

Portfolio Optimization in a Semi-Markov Modulated Market

We address a portfolio optimization problem in a semi-Markov modulated market. We study both the terminal expected utility optimization on finite time horizon and the risk-sensitive portfolio optimization on finite and infinite time horizon. We obtain optimal portfolios in relevant cases. A numerical procedure is also developed to compute the optimal expected terminal utility for finite horizon problem.

Resilience of a high-conservation-value, semi-arid grassland on fertile clay soils to burning, mowing and ploughing.

In grassland reserves, managed disturbance is often necessary to maintain plant species diversity. We carried out experiments to determine the impact of fire, kangaroo grazing, mowing and disc ploughing on grassland species richness and composition in a nature reserve in semi-arid eastern Australia. Vegetation response was influenced by winter-spring drought after establishment of the experiments, but moderate rainfall followed in late summer-autumn. Species composition varied greatly between sampling times, and the variability due to rainfall differences between seasons and years was greater than the effects of fire, kangaroo grazing, mowing or disc ploughing. In the fire experiment, species richness and composition recovered more rapidly after spring than autumn burning. Species richness and composition were similar to control sites within 12 months of burning and mowing, suggesting that removal of the dominant grass canopy is unnecessary to enhance plant diversity. Two fires (separated by 3 years) and post-fire kangaroo grazing had only minor influence on species richness and composition. Even disc ploughing caused only a small reduction in native richness. The minor impact of ploughing was explained by the small areas that were ploughed, the once-off nature of the treatment, and the high degree of natural movement and cracking in these shrink-swell soils. Recovery of the composition and richness of these grasslands was rapid because of the high proportion of perennial species that resprout vegetatively after fire and mowing. There appears to be little conservation benefit from fire, mowing or ploughing ungrazed areas, as we could identify no native plant species dependent on frequent disturbance for persistence in this grassland community. However, the ability of the Astrebla- and Dichanthium-dominated grasslands to recover quickly after disturbance, given favourable seasonal conditions, suggests that they are well adapted to natural disturbances (e.g. droughts, fire, flooding and native grazing).

Unsteady flow of a dilute suspension in a semi-infinite contracting or expanding pipe

In the present paper an exact similar solution of the Navier-Stokes equation for unsteady flow of a dilute suspension in a semi-infinite contracting or expanding circular pipe is presented. The effects of the Schmidt number (Sc), Reynolds number (|ε|), the volume fraction (α) and the relaxation time (τ) of the particulate phase on the flow characteristics are examined. The presence of the solid particles has been observed to influence the flow behaviour significantly. These solutions are valid down to the state of a completely collapsed pipe, since the nonlinearity is retained fully. The results may help understanding the flow near the heart and certain forced contractions or expansions of valved veins.

Metal chelates in vinyl polymerization: Kinetics and mechanism of acrylonitrile polymerization initiated by Cu(II) imine complexes

The free radical polymerization of acrylonitrile (AN) initiated by Cu(II) 4-anilino 2-one [Cu(II) ANIPO] Cu(II), 4-p-toluedeno 3-pentene 2-one [Cu(II) TPO], and Cu(II) 4-p-nitroanilino 3-pentene 2-one [Cu(II) NAPO] was studied in benzene at 50 and 60°C and in carbon tetrachloride (CCl4), dimethyl sulfoxide (DMSO), and methanol (MeOH) at 60°C. Although the polymerization proceeded in a heterogeneous phase, it followed the kinetics of a homogeneous process. The monomer exponents were 2 at two different temperatures and in different solvents. The square-root dependence of Rp on initiator concentration and higher monomer exponents accounted for a 1:2 complex formation between the chelate and monomer. The complex formation was shown by ultraviolet (UV) study. The activation energies, kinetics, and chain transfer constants were also evaluated.

Interatomic Auger transitions in transition-metal oxides

Interatomic L3(M)M23(M)V(O) and L3(M)V(O)V(O) Auger transitions of some transition-metal oxides are reported for the first time. The interatomic mode of decay becomes progressively more dominant (relative to the intra-atomic mode) as the metal d level gets depleted or as the oxidation state of the metal increases. The usefulness of interatomic Auger transitions in studying oxidation of metals has been examined.

Adsorption of CO and N2 on modified transition-metal surfaces

Electron spectroscopic studies clearly demonstrate that modification of the surfaces of Mn, Fe and Ni metals by chlorine significantly decreases the strength of interaction between the metal and adsorbed molecules such as CO and N2. This is in contrast to the effect of electropositive additives such as Ba and Al which increase the adsorption bond strength significantly.

X-Ray Structure Of A Ternary Metal-Complex - Copper(Ii) Inosine 5'-Monophosphate Imidazole - Metal-Binding To The N(7) Atom Of The Nucleotide In A Mixed-Ligand System Containing An Aromatic Amine

A ternary metal-nucleotide complex, Na2[Cu(5’-IMP)2(im)o,8(H20)l,2(H20)2h]as~ 1be2e.n4 pHr2ep0a,r ed and its structure analyzed by X-ray diffraction (5’-IMP = inosine 5’-monophos hate; im = imidazole). The complex crystallizes in space group C222, with a = 8.733 (4) A, b = 23.213 (5) A, c = 21.489 (6) 1, and Z = 4. The structure was solved by the heavy-atom method and refined by full-matrix least-squares technique on the basis of 2008 observed reflections to a final R value of 0.087. Symmetry-related 5’-IMP anions coordinate in cis geometry through the N(7) atoms of the bases. The other cis positions of the coordination plane are statistically occupied by nitrogen atoms of disordered im groups and water oxygens with occupancies 0.4 and 0.6, respectively. Water oxygens in axial positions complete the octahedral coordination of Cu(I1). The complex is isostructural with C~S-[P~(S’-IMP),(NH~)~a] m”,o del proposed for Pt(I1) binding to DNA. The base binding observed in the present case is different from the typical ”phosphate only” binding shown from earlier studies on metal-nucleotide complexes containing various other ?r-aromatic amines.

Metal Auger intensity ratios as a probe for change-transfer effects in aluminum-covered transition metal

Marked changes in the LVV/LMV and LVV/LMM Auger intensity ratios of Co, Ni and Cu are observed on depositing Al on their surfaces. These changes, ascribed to charge-transfer or hybridization effects, are accompanied by changes in the intensity of the satellites next to the core levels of the transition metals.

Anionic clay-Pt metal nanoparticle composite through intercalation of hexachloroplatinate in nickel zinc hydroxysalt

Nickel zinc hydroxysalt–Pt metal nanoparticle composite was prepared by intercalation of the anionic platinum complex, [PtCl6]2− in nickel zinc hydroxysalt through ion exchange reaction and subsequent reduction of the platinum complex by ethanol. Powder X-ray diffraction and microscopy studies indicate that the process of reduction of the platinum complex in the interlayer region of the anionic clay takes place topotactically without destroying the layers.