461 research outputs found
‘Roving Vultures’. Television News and the Outbreak of the Troubles in Northern Ireland
Almost exactly fifty years ago, an illegal Civil Rights march in Londonderry in Northern Ireland was broken up by the local police force, the Royal Ulster Constabulary. Hitherto, Northern Ireland, although a constituent part of the UK kingdom, was an unknown quantity for most British people, who knew or cared little about its endemic sectarian problems, and its one-sided and discriminatory system of government. Had the march taken place in 1958 rather than 1968, it very likely would be remained only an item of local interest and controversy. However, the presence in 1968 of three television crews, who recorded what transpired, meant that the problems of the Province were cruelly exposed, leading to a spiral of violence known as ‘the Troubles’ which would cost the lives of some 3,600 people in the succeeding decades
‘No Pope Here.’ Britain, the Vatican, the IRA and the Papal Visit to Ireland, September 1979
It is often assumed, particularly by outsiders, that the conflict in Northern Ireland, known euphemistically as ‘the Troubles’, in which some 3,600 people lost their lives, was an atavistic throwback to Europe’s religious wars of earlier centuries. In 1979, by which time some 2,000 people had already been killed in the Troubles, Pope John Paul II proposed to pay a visit to Ireland, and perhaps to cross the border into Ulster’s sectarian cockpit. The idea provoked outrage from some Ulster protestants and high anxiety for the British, concerned that the Pope might inadvertently enflame the situation or embarrass the British by raising difficult issues. But there were hopes too that an unequivocal condemnation of violence by the head of the Catholic Church, might help to bring the conflict to an end. This article, based on extensive research in diplomatic archives, reveals deep divisions within the Catholic Church on the Irish question and points to the power and limitations of the British diplomatic reach into the Vatican. It reveals also, however, the powerlessness of prayer and pleadings in the face of terrorist violence
Constructing Entanglement Witness Via Real Skew-Symmetric Operators
In this work, new types of EWs are introduced. They are constructed by using
real skew-symmetric operators defined on a single party subsystem of a
bipartite dxd system and a maximal entangled state in that system. A canonical
form for these witnesses is proposed which is called canonical EW in
corresponding to canonical real skew-symmetric operator. Also for each possible
partition of the canonical real skew-symmetric operator corresponding EW is
obtained. The method used for dxd case is extended to d1xd2 systems. It is
shown that there exist Cd2xd1 distinct possibilities to construct EWs for a
given d1xd2 Hilbert space. The optimality and nd-optimality problem is studied
for each type of EWs. In each step, a large class of quantum PPT states is
introduced. It is shown that among them there exist entangled PPT states which
are detected by the constructed witnesses. Also the idea of canonical EWs is
extended to obtain other EWs with greater PPT entanglement detection power.Comment: 40 page
Efficient measurements, purification, and bounds on the mutual information
When a measurement is made on a quantum system in which classical information
is encoded, the measurement reduces the observers average Shannon entropy for
the encoding ensemble. This reduction, being the {\em mutual information}, is
always non-negative. For efficient measurements the state is also purified;
that is, on average, the observers von Neumann entropy for the state of the
system is also reduced by a non-negative amount. Here we point out that by
re-writing a bound derived by Hall [Phys. Rev. A {\bf 55}, 100 (1997)], which
is dual to the Holevo bound, one finds that for efficient measurements, the
mutual information is bounded by the reduction in the von Neumann entropy. We
also show that this result, which provides a physical interpretation for Hall's
bound, may be derived directly from the Schumacher-Westmoreland-Wootters
theorem [Phys. Rev. Lett. {\bf 76}, 3452 (1996)]. We discuss these bounds, and
their relationship to another bound, valid for efficient measurements on pure
state ensembles, which involves the subentropy.Comment: 4 pages, Revtex4. v3: rewritten and reinterpreted somewha
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Gold-reinforced silver nanoprisms on optical fiber tapers - A new base for high precision sensing
Due to their unique optical properties, metallic nanoparticles offer a great potential for important applications such as disease diagnostics, demanding highly integrated device solutions with large refractive index sensitivity. Here we introduce a new type of monolithic localized surface plasmon resonance (LSPR) waveguide sensor based on the combination of an adiabatic optical fiber taper and a high-density ensemble of immobilized gold-reinforced silver nanoprisms, showing sensitivities up to 900 nm/RIU. This result represents the highest value reported so far for a fiber optic sensor using the LSPR effect and exceeds the corresponding value of the bulk solution by a factor of two. The plasmonic resonance is efficiently excited via the evanescent field of the propagating taper mode, leading to pronounced transmission dips (−20 dB). The particle density is so high (approx. 210 particle/μm2) that neighboring particles are able to interact, boosting the sensitivity, as confirmed by qualitative infinite element simulations. We additionally introduce a qualitative model explaining the interaction of plasmon resonance and taper mode on the basis of light extinction, allowing extracting key parameters of the plasmonic taper (e.g., modal attenuation). Due to the monolithic design and the extremely high sensitivity we expect our finding to be relevant in fields such as biomedicine, disease diagnostics, and molecular sensing
Interface roughening with nonlinear surface tension
Using stability arguments, this Brief Report suggests that a term that
enhances the surface tension in the presence of large height fluctuations
should be included in the Kardar-Parisi-Zhang equation. A one-loop
renormalization group analysis then shows for interface dimensions larger than
an unstable strong-coupling fixed point that enters the system
from infinity. The relevance of these results to the roughening transition is
discussed.Comment: 4 pages RevTeX, 1 figur
Topological order in 1D Cluster state protected by symmetry
We demonstrate how to construct the Z2*Z2 global symmetry which protects the
ground state degeneracy of cluster states for open boundary conditions. Such a
degeneracy ultimately arises because the set of stabilizers do not span a
complete set of integrals of motion of the cluster state Hamiltonian for open
boundary conditions. By applying control phase transformations, our
construction makes the stabilizers into the Pauli operators spanning the qubit
Hilbert space from which the degeneracy comes.Comment: 1 figure, To be published in Quantum Information Processin
Mutation in NSUN2, which Encodes an RNA Methyltransferase, Causes Autosomal-Recessive Intellectual Disability
Causes of autosomal-recessive intellectual disability (ID) have, until very recently, been under researched because of the high degree of genetic heterogeneity. However, now that genome-wide approaches can be applied to single multiplex consanguineous families, the identification of genes harboring disease-causing mutations by autozygosity mapping is expanding rapidly. Here, we have mapped a disease locus in a consanguineous Pakistani family affected by ID and distal myopathy. We genotyped family members on genome-wide SNP microarrays and used the data to determine a single 2.5 Mb homozygosity-by-descent (HBD) locus in region 5p15.32–p15.31; we identified the missense change c.2035G>A (p.Gly679Arg) at a conserved residue within NSUN2. This gene encodes a methyltransferase that catalyzes formation of 5-methylcytosine at C34 of tRNA-leu(CAA) and plays a role in spindle assembly during mitosis as well as chromosome segregation. In mouse brains, we show that NSUN2 localizes to the nucleolus of Purkinje cells in the cerebellum. The effects of the mutation were confirmed by the transfection of wild-type and mutant constructs into cells and subsequent immunohistochemistry. We show that mutation to arginine at this residue causes NSUN2 to fail to localize within the nucleolus. The ID combined with a unique profile of comorbid features presented here makes this an important genetic discovery, and the involvement of NSUN2 highlights the role of RNA methyltransferase in human neurocognitive development
Quantum circuits for spin and flavor degrees of freedom of quarks forming nucleons
We discuss the quantum-circuit realization of the state of a nucleon in the
scope of simple symmetry groups. Explicit algorithms are presented for the
preparation of the state of a neutron or a proton as resulting from the
composition of their quark constituents. We estimate the computational
resources required for such a simulation and design a photonic network for its
implementation. Moreover, we highlight that current work on three-body
interactions in lattices of interacting qubits, combined with the
measurement-based paradigm for quantum information processing, may also be
suitable for the implementation of these nucleonic spin states.Comment: 5 pages, 2 figures, RevTeX4; Accepted for publication in Quantum
Information Processin
High dimensional behavior of the Kardar-Parisi-Zhang growth dynamics
We investigate analytically the large dimensional behavior of the
Kardar-Parisi-Zhang (KPZ) dynamics of surface growth using a recently proposed
non-perturbative renormalization for self-affine surface dynamics. Within this
framework, we show that the roughness exponent decays not faster than
for large . This implies the absence of a finite upper
critical dimension.Comment: RevTeX, 4 pages, 2 figures. To appear in Phys. Rev.
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