Eg versus x relation from photoluminescence and electron microprobe investigations in p-type Hg1−xCdxTe (0.35 =< x =< 0.7)

Combined photoluminescence (at 10 T 300 K) and electron microprobe investigations have been carried out with HgCdTe samples grown from the melt or from solution. By exciting the samples through metallic masks with 200 μm diameter holes fixed with respect to the sample care was taken to pick-up both characteristic X-ray radiation as well as the photoluminescence from the same sample area. The Eg versus x relation determined in this way at T = 30 K has been compared with data from the interband absorption edge by other authors

The Influence Of Neutron Capture Rates On The Rare Earth Region Of The r-Process Abundance Pattern

We study the sensitivity of the r-process abundance pattern to neutron capture rates along the rare earth region (A~150 to A~180). We introduce the concepts of large nuclear flow and flow saturation which determine the neutron capture rates that are influential in setting the rare earth abundances. We illustrate the value of the two concepts by considering high entropy conditions favorable for rare earth peak production and identifying important neutron capture rates among the rare earth isotopes. We also show how these rates influence nuclear flow and specific sections of the abundance pattern.Comment: 14 pages, 7 figures, submitted to PR

'Parasitic invasions' or sources of good governance: constraining foreign competition in Hong Kong banking, 1956-81

This paper investigates the operation and impact of the moratorium on new banking licences imposed in Hong Kong in 1965 and the claims that foreign banks destabilised the banking system and drained resources from the colony. First it examines foreign banks' attempts to circumvent the moratorium through claims of special circumstances and buying interests in local banks, and secondly it examines the efforts of incumbents to extend barriers to non-bank financial institutions and to branches of foreign banks. The general conclusions are that while the moratorium was aimed at increasing the stability of the banking system, it had the effect of decreasing the regulatory breadth of the government, and reducing incentives for mergers and acquisitions that might have improved governance

Deoxyephedrine -- mandelic acid diastereomers

Resolution of mandelic acid with (-)(R)-deoxyephedrine in 95% ethanol produces essentially nondiscriminating unsolvated binary mandelate salts. (R)deoxyephedrinium (R)-mandelate (I) is orthorhombic, P212121, a = 8.076(2) Å, b = 8.926(3) Å, c = 23.242(15) Å, V = 1675.3(14) Å3 , Z = 4. (R)-deoxyephedrinium (S)-mandelate (II) is monoclinic, P21, a = 16.061(14) Å, b = 8.902(8) Å, c = 19.585(20) Å, β = 111.76(8)°, V = 2600(4) Å3, Z = 6 with three ionpairs comprising the asymmetric unit. The principle interionic interactions are ribbon-like chains of salt-bridge hydrogen bonds which associate protonated secondary ammonium ions with carboxylates in I and II along crystallographic screw axes with a six-atom repeating unit H-N+-H ··· O-C--O [C22(6)]. The (R)-mandelate additionally shows intraion hydrogen bonding and the (S)-mandelate shows interanion hydrogen bonding. Solubilities (in 95% ethanol), fusion points and heats of fusion indicate essentially no diastereometric discrimination. From acetone, the (S)-mandelate salt forms a efflorescent hemiacetone solvated binary phase (III), triclinic, P1, a = 10.869(9) Å, b = 10.838(13) Å, c = 17.138(18) Å, α = 90.32(9)°, β = 91.34(8)°, γ = 108.20(8)°, V = 1917(4) Å3, Z = 4. Ions form hydrogen bonded chains similar to those in II; acetones are unassociated. In I, columns form with the polar hydrogen bonded chains at the core and nonpolar aryl rings radiating and interdigitating adjacent columns. Packing in II and III produces bilayers of alternating polar and nonpolar regions, with acetones of III in the nonpolar regions

Tuning the superconducting and magnetic properties in Fe_ySe_0.25Te_0.75 by varying the Fe-content

The superconducting and magnetic properties of Fe$_{y}$Se$_{0.25}$Te$_{0.75}$ single crystals ($0.9\leq y \leq1.1$) were studied by means of x-ray diffraction, SQUID magnetometry, muon spin rotation, and elastic neutron diffraction. The samples with $y<1$ exhibit coexistence of bulk superconductivity and incommensurate magnetism. The magnetic order remains incommensurate for $y\geq 1$, but with increasing Fe content superconductivity is suppressed and the magnetic correlation length increases. The results show that the superconducting and the magnetic properties of the Fe$_{y}$Se$_{1-x}$Te$_{x}$ can be tuned not only by varying the Se/Te ratio but also by changing the Fe content

Critical Behaviour of the Drossel-Schwabl Forest Fire Model

We present high statistics Monte Carlo results for the Drossel-Schwabl forest fire model in 2 dimensions. They extend to much larger lattices (up to $65536\times 65536$) than previous simulations and reach much closer to the critical point (up to $\theta \equiv p/f = 256000$). They are incompatible with all previous conjectures for the (extrapolated) critical behaviour, although they in general agree well with previous simulations wherever they can be directly compared. Instead, they suggest that scaling laws observed in previous simulations are spurious, and that the density $\rho$ of trees in the critical state was grossly underestimated. While previous simulations gave $\rho\approx 0.408$, we conjecture that $\rho$ actually is equal to the critical threshold $p_c = 0.592...$ for site percolation in $d=2$. This is however still far from the densities reachable with present day computers, and we estimate that we would need many orders of magnitude higher CPU times and storage capacities to reach the true critical behaviour -- which might or might not be that of ordinary percolation.Comment: 8 pages, including 9 figures, RevTe

Phylogeny and floral character evolution of Mentzelia section Bicuspidaria (Loasaceae)

Mentzelia section Bicuspidaria (Loasaceae) is a monophyletic group of desert ephemerals that inhabit the complex, heterogeneous landscapes of the southwestern United States and northwestern Mexico. To investigate species circumscriptions and evolutionary relationships in M. sect. Bicuspidaria, we employed phylogeny reconstructions based on DNA sequences from the plastid trnL-trnF, trnS-trnfM, ndhF-rpl32, and rpl32-trnL regions and the nuclear ribosomal ITS and ETS regions. Due to evidence of discordant relationships reconstructed from the plastid and nuclear partitions, we used coalescent-based methods in addition to concatenated data sets to estimate the species tree. Maximum likelihood reconstructions based on the combined plastid and nuclear data and coalescent-based reconstructions inferred congruent, fully-resolved species-level phylogenies of M. sect. Bicuspidaria. A monophyletic M. sect. Bicuspidaria was composed of two main clades, which corresponded to a clade of species endemic to the United States composed of M. reflexa, M. tricuspis, and M. tridentata that was sister to a clade of species at least partially distributed in Mexico, composed of M. hirsutissima and M. involucrata. Despite the unusual floral morphology of M. reflexa, molecular reconstructions placed M. reflexa sister to M. tridentata. All species of M. sect. Bicuspidaria were monophyletic, except for M. hirsutissima, which was composed of two distinct lineages and paraphyletic with respect to M. involucrata. The northern clade of M. hirsutissima from California and Baja California was sister to M. involucrata, and both, in turn, were sister to a geographically disjunct southern clade of M. hirsutissima from Baja California Sur and Cedros Island. These phylogeny reconstructions provide evidence for the inclusion of five species in M. sect. Bicuspidaria and have uncovered cryptic diversity that has been largely unrecognized. Character state reconstructions based on the phylogeny of M. sect. Bicuspidaria suggest innovative and, at times, homoplasious floral evolution