991 research outputs found
The Shallow Geological Model: mapping and monitoring the marine landscape
Managing our seas without a sound knowledge of the sea-bed environment and the
processes that shape the sea-bed characteristics makes it difficult to conserve key areas,
maintain biodiversity and economically develop our marine resources in an efficient and
sustainable way. Recent developments in marine landscape mapping, visualisation
techniques and instant data access provide timely, proven technologies that are now in
widespread use
Progressive internal gravity waves with bounded upper surface climbing a triangular obstacle
In this paper we discuss a theoretical model for the interfacial profiles of
progressive non-linear waves which result from introducing a triangular
obstacle, of finite height, attached to the bottom below the flow of a
stratified, ideal, two layer fluid, bounded from above by a rigid boundary. The
derived equations are solved by using a nonlinear perturbation method. The
dependence of the interfacial profile on the triangular obstacle size, as well
as its dependence on some flow parameters, such as the ratios of depths and
densities of the two fluids, have been studied
Experimental NMR Realization of A Generalized Quantum Search Algorithm
A generalized quantum search algorithm, where phase inversions for the marked
state and the prepared state are replaced by phase rotations, is
realized in a 2-qubit NMR heteronuclear system. The quantum algorithm searches
a marked state with a smaller step compared to standard Grover algorithm. Phase
matching requirement in quantum searching is demonstrated by comparing it with
another generalized algorithm where the two phase rotations are and
respectively. Pulse sequences which include non 90 degree pulses are
given.Comment: 12 pages, 2 figures, accepted for publication in Plysics Letters
Discrimination, labour markets and the Labour Market Prospects of Older Workers: What Can a Legal Case Teach us?
As governments become increasingly concerned about the fiscal implications of the ageing population, labour market policies have sought to encourage mature workers to remain in the labour force. The ‘human capital’ discourses motivating these policies rest on the assumption that older workers armed with motivation and vocational skills will be able to return to fulfilling work. This paper uses the post-redundancy recruitment experiences of former Ansett Airlines
flight attendants to develop a critique of these expectations. It suggests that policies to increase
older workers’ labour market participation will not succeed while persistent socially constructed age- and gender- typing shape labour demand. The conclusion argues for policies sensitive to the institutional structures that shape employer preferences, the competitive rationality of
discriminatory practices, and the irresolvable tension between workers’ human rights and employers’ property rights
On the magnetism of Ln{2/3}Cu{3}Ti{4}O{12} (Ln = lanthanide)
The magnetic and thermodynamic properties of the complete
LnCuTiO series were investigated. Here stands for
the lanthanides La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb. %Most
of the compounds were prepared as single phase polycrystalline powder %without
any traces of impurities. Marginal amounts of %impurities were
detected Gd, Er, and Tm. %Significant amounts of impurity phases were
found for Ce and Yb. All the samples investigated crystallize in the
space group with lattice constants that follow the lanthanide
contraction. The lattice constant of the Ce compound reveals the presence of
Ce leading to the composition CeCuTiO. From
magnetic susceptibility and electron-spin resonance experiments it can be
concluded that the copper ions always carry a spin and order
antiferromagnetically close to 25\,K. The Curie-Weiss temperatures can
approximately be calculated assuming a two-sublattice model corresponding to
the copper and lanthanide ions, respectively. It seems that the magnetic
moments of the heavy rare earths are weakly coupled to the copper spins, while
for the light lanthanides no such coupling was found. The moments remain
paramagnetic down to the lowest temperatures, with the exception of the Tm
compound, which indicates enhanced Van-Vleck magnetism due to a non-magnetic
singlet ground state of the crystal-field split manifold. From
specific-heat measurements we accurately determined the antiferromagnetic
ordering temperature and obtained information on the crystal-field states of
the rare-earth ions. The heat-capacity results also revealed the presence of a
small fraction of Ce in a magnetic state.Comment: 10 pages, 10 figure
Scalar Potential Without Cubic Term in 3-3-1 Models Without Exotic Electric Charges
A detailed study of the criteria for stability of the scalar potential, and
the proper electroweak symmetry breaking pattern in some 3-3-1 models without
exotic electric charges is presented. In this paper we concentrate in a scalar
sector with three Higgs scalar triplets, with a potential that does not include
the cubic term, due to the presence of a discrete symmetry. For the analysis we
use, and improve, a method previously developed to study the scalar potential
in the two-Higgs-doublet extension of the standard model. Our main result is to
show the consistency of those 3-3-1 models without exotic electric charges.Comment: 19 page
Colossal dielectric constants in transition-metal oxides
Many transition-metal oxides show very large ("colossal") magnitudes of the
dielectric constant and thus have immense potential for applications in modern
microelectronics and for the development of new capacitance-based
energy-storage devices. In the present work, we thoroughly discuss the
mechanisms that can lead to colossal values of the dielectric constant,
especially emphasising effects generated by external and internal interfaces,
including electronic phase separation. In addition, we provide a detailed
overview and discussion of the dielectric properties of CaCu3Ti4O12 and related
systems, which is today's most investigated material with colossal dielectric
constant. Also a variety of further transition-metal oxides with large
dielectric constants are treated in detail, among them the system La2-xSrxNiO4
where electronic phase separation may play a role in the generation of a
colossal dielectric constant.Comment: 31 pages, 18 figures, submitted to Eur. Phys. J. for publication in
the Special Topics volume "Cooperative Phenomena in Solids: Metal-Insulator
Transitions and Ordering of Microscopic Degrees of Freedom
Time-Dependent CP Violation Effects in Partially Reconstructed Decays
We report measurements of time-dependent decay rates for decays and extraction of CP violation parameters related to .
We use a partial reconstruction technique, whereby signal events are identified
using information only from the primary pion and the charged pion from the
decay of the . The analysis uses of data
accumulated at the resonance with the Belle detector at the KEKB
asymmetric-energy collider. We measure the CP violation parameters
and .Comment: 15 pages, 5 figures. To appear in Physics Letters
Pharmacology and Surface Electrostatics of the K Channel Outer Pore Vestibule
In spite of a generally well-conserved outer vestibule and pore structure, there is considerable diversity in the pharmacology of K channels. We have investigated the role of specific outer vestibule charged residues in the pharmacology of K channels using tetraethylammonium (TEA) and a trivalent TEA analog, gallamine. Similar to Shaker K channels, gallamine block of Kv3.1 channels was more sensitive to solution ionic strength than was TEA block, a result consistent with a contribution from an electrostatic potential near the blocking site. In contrast, TEA block of another type of K channel (Kv2.1) was insensitive to solution ionic strength and these channels were resistant to block by gallamine. Neutralizing either of two lysine residues in the outer vestibule of these Kv2.1 channels conferred ionic strength sensitivity to TEA block. Kv2.1 channels with both lysines neutralized were sensitive to block by gallamine, and the ionic strength dependence of this block was greater than that for TEA. These results demonstrate that Kv3.1 (like Shaker) channels contain negatively charged residues in the outer vestibule of the pore that influence quaternary ammonium pharmacology. The presence of specific lysine residues in wild-type Kv2.1 channels produces an outer vestibule with little or no net charge, with important consequences for quaternary ammonium block. Neutralizing these key lysines results in a negatively charged vestibule with pharmacological properties approaching those of other types of K channels
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