550 research outputs found
Mechanism of Deep-focus Earthquakes Anomalous Statistics
Analyzing the NEIC-data we have shown that the spatial deep-focus earthquake
distribution in the Earth interior over the 1993-2006 is characterized by the
clearly defined periodical fine discrete structure with period L=50 km, which
is solely generated by earthquakes with magnitude M 3.9 to 5.3 and only on the
convergent boundary of plates. To describe the formation of this structure we
used the model of complex systems by A. Volynskii and S. Bazhenov. The key
property of this model consists in the presence of a rigid coating on a soft
substratum. It is shown that in subduction processes the role of a rigid
coating plays the slab substance (lithosphere) and the upper mantle acts as a
soft substratum. Within the framework of this model we have obtained the
estimation of average values of stress in the upper mantle and Young's modulus
for the oceanic slab (lithosphere) and upper mantle.Comment: 9 pages, 7 figure
Low level of virological failure and drug resistance among patients receiving antiretroviral treatment under programme conditions in Maputo, Mozambique
Mexico AIDS Conference 200
The Biot-Savart operator and electrodynamics on subdomains of the three-sphere
We study steady-state magnetic fields in the geometric setting of positive
curvature on subdomains of the three-dimensional sphere. By generalizing the
Biot-Savart law to an integral operator BS acting on all vector fields, we show
that electrodynamics in such a setting behaves rather similarly to Euclidean
electrodynamics. For instance, for current J and magnetic field BS(J), we show
that Maxwell's equations naturally hold. In all instances, the formulas we give
are geometrically meaningful: they are preserved by orientation-preserving
isometries of the three-sphere.
This article describes several properties of BS: we show it is self-adjoint,
bounded, and extends to a compact operator on a Hilbert space. For vector
fields that act like currents, we prove the curl operator is a left inverse to
BS; thus the Biot-Savart operator is important in the study of curl
eigenvalues, with applications to energy-minimization problems in geometry and
physics. We conclude with two examples, which indicate our bounds are typically
within an order of magnitude of being sharp.Comment: 24 pages (was 28 pages) Revised to include a new introduction, a
detailed example, and results about helicity; other changes for readabilit
The Chagos Islands cases: the empire strikes back
Good governance requires the accommodation of multiple interests in the cause of decision making. However, undue regard for particular sectional interests can take their toll upon public faith in government administration. Historically, broad conceptions of the good of the commonwealth were employed to outweigh the interests of groups that resisted colonisation. In the decision making of the British Empire, the standard approach for justifying the marginalisation of the interests of colonised groups was that they were uncivilised and that particular hardships were the price to be paid for bringing to them the imperial dividend of industrial society. It is widely assumed that with the dismantling of the British Empire, such impulses and their accompanying jurisprudence became a thing of the past. Even as decolonisation proceeded apace after the Second World War, however, the United Kingdom maintained control of strategically important islands with a view towards sustaining its global role. In an infamous example from this twilight period of empire, in the 1960s imperial interests were used to justify the expulsion of the Chagos islanders from the British Indian Ocean Territory (BIOT). Into the twenty-first century, this forced elision of the UK’s interests with the imperial “common good” continues to take centre stage in courtroom battles over the islanders’ rights, being cited before domestic and international tribunals in order to maintain the Chagossians’ exclusion from their homeland. This article considers the new jurisprudence of imperialism which has emerged in a string of decisions which have continued to marginalise the Chagossians’ interests
High frequency poroelastic waves in hydrogels
In this work a continuum model for high frequency poroelastic longitudinal
waves in hydrogels is presented. A viscoelastic force describing the
interaction between the polymer network and the bounded water present in such
materials is introduced. The model is tested by means of ultrasound wave speed
and attenuation measurements in polyvinylalcohol hydrogel samples. The theory
and experiments show that ultrasound attenuation decreases linearly with the
increase of the water volume fraction "{\beta}" of the hydrogel. The
introduction of the viscoelastic force between the bounded water and the
polymer network leads to a bi-phasic theory showing an ultrasonic fast wave
attenuation that can vary as a function of the frequency with a non-integer
exponent in agreement with the experimental data in literature. When {\beta}
tends to 1 (100% of interstitial water) due to the presence of bounded water in
the hydrogel, the ultrasound phase velocity acquires higher value than that of
pure water. The ultrasound speed gap at {\beta} = 1 is confirmed by the
experimental results that show that it increases in less cross-linked gel
samples that own a higher concentration of bounded water
Bis(2-{[2,8-bis(trifluoromethyl)quinolin-4-yl](hydroxy)methyl}piperidin-1-ium) tetrachloridodiphenylstannate(IV)
In the title salt, (C17H17F6N2O)2[Sn(C6H5)2Cl4], the complete anion is generated by crystallograaphic inversion symmetry, giving a trans-SnC2Cl4 octahedral coordination geometry for the metal atom. In the cation, the quinoline residue is almost normal to the other atoms, so that the ion has an L-shaped conformation [the C—C—C—C torsion angle linking the fused-ring systems is 100.9 (7)°]; the six-membered piperidin-1-ium ring has a chair conformation. An intramolecular N—H⋯O interaction occurs. In the crystal, N—H⋯Cl and O—H⋯Cl hydrogen bonds link the components into a supramolecular chain propagating along the a axis. C—H⋯Cl interactions are also present
Superconductors with Magnetic Impurities: Instantons and Sub-gap States
When subject to a weak magnetic impurity potential, the order parameter and
quasi-particle energy gap of a bulk singlet superconductor are suppressed.
According to the conventional mean-field theory of Abrikosov and Gor'kov, the
integrity of the energy gap is maintained up to a critical concentration of
magnetic impurities. In this paper, a field theoretic approach is developed to
critically analyze the validity of the mean field theory. Using the
supersymmetry technique we find a spatially homogeneous saddle-point that
reproduces the Abrikosov-Gor'kov theory, and identify instanton contributions
to the density of states that render the quasi-particle energy gap soft at any
non-zero magnetic impurity concentration. The sub-gap states are associated
with supersymmetry broken field configurations of the action. An analysis of
fluctuations around these configurations shows how the underlying supersymmetry
of the action is restored by zero modes. An estimate of the density of states
is given for all dimensionalities. To illustrate the universality of the
present scheme we apply the same method to study `gap fluctuations' in a normal
quantum dot coupled to a superconducting terminal. Using the same instanton
approach, we recover the universal result recently proposed by Vavilov et al.
Finally, we emphasize the universality of the present scheme for the
description of gap fluctuations in d-dimensional superconducting/normal
structures.Comment: 18 pages, 9 eps figure
Espon-Interstrat. Espon in Integrated Territorial Strategies.
The INTERSTRAT project’s overall aim is “to encourage and facilitate the use of ESPON 2013 Programme findings in the creation and monitoring of Integrated Territorial Development Strategies (ITDS) and to support transnational learning about the actual and potential contribution of ESPON to integrated policy-making.” We defined integrated territorial development as ‘the process of shaping economic, social and environmental change through spatially sensitive policies and programmes’
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