4,834 research outputs found
Party finance reform as constitutional engineering? The effectiveness and unintended consequences of party finance reform in France and Britain
In both Britain and France, party funding was traditionally characterized by a laissez faire approach and a conspicuous lack of regulation. In France, this was tantamount to a 'legislative vacuum'. In the last two decades, however, both countries have sought to fundamentally reform their political finance regulation regimes. This prompted, in Britain, the Political Parties, Elections and Referendums Act 2000, and in France a bout of 'legislative incontinence' â profoundly transforming the political finance regime between 1988 and 1995. This article seeks to explore and compare the impacts of the reforms in each country in a bid to explain the unintended consequences of the alternative paths taken and the effectiveness of the new party finance regime in each country. It finds that constitutional engineering through party finance reform is a singularly inexact science, largely due to the imperfect nature of information, the limited predictability of cause and effect, and the constraining influence of non-party actors, such as the Constitutional Council in France, and the Electoral Commission in Britain
Thermodynamic analysis of the Quantum Critical behavior of Ce-lattice compounds
A systematic analysis of low temperature magnetic phase diagrams of Ce
compounds is performed in order to recognize the thermodynamic conditions to be
fulfilled by those systems to reach a quantum critical regime and,
alternatively, to identify other kinds of low temperature behaviors. Based on
specific heat () and entropy () results, three different types of
phase diagrams are recognized: i) with the entropy involved into the ordered
phase () decreasing proportionally to the ordering temperature
(), ii) those showing a transference of degrees of freedom from the
ordered phase to a non-magnetic component, with their jump
() vanishing at finite temperature, and iii) those ending in a
critical point at finite temperature because their do not decrease
with producing an entropy accumulation at low temperature.
Only those systems belonging to the first case, i.e. with as
, can be regarded as candidates for quantum critical behavior.
Their magnetic phase boundaries deviate from the classical negative curvature
below \,K, denouncing frequent misleading extrapolations down to
T=0. Different characteristic concentrations are recognized and analyzed for
Ce-ligand alloyed systems. Particularly, a pre-critical region is identified,
where the nature of the magnetic transition undergoes significant
modifications, with its discontinuity strongly
affected by magnetic field and showing an increasing remnant entropy at . Physical constraints arising from the third law at are discussed
and recognized from experimental results
Trapping colloids near chemical stripes via critical Casimir forces
We study theoretically and experimentally the solvent-mediated critical
Casimir force acting on colloidal particles immersed in a binary liquid mixture
of water and 2,6-lutidine and close to substrates which are chemically
patterned with periodically alternating stripes of antagonistic adsorption
preferences. These patterns are experimentally realized via microcontact
printing. Upon approaching the critical demixing point of the solvent, normal
and lateral critical Casimir forces generate laterally confining effective
potentials for the colloids. We analyze in detail the rich behavior of the
spherical colloids close to such substrates. For all patterned substrates we
investigated, our measurements of these effective potentials agree with the
corresponding theoretical predictions. Since both the directions and the
strengths of the critical Casimir forces can be tuned by minute temperature
changes, this provides a new mechanism for controlling colloids as model
systems, opening encouraging perspectives for applications.Comment: Invited contribution to Molecular Physics Special Issue on Bob Evans'
65th birthda
Ambipolar Field Effect in Topological Insulator Nanoplates of (BixSb1-x)2Te3
Topological insulators represent a new state of quantum matter attractive to
both fundamental physics and technological applications such as spintronics and
quantum information processing. In a topological insulator, the bulk energy gap
is traversed by spin-momentum locked surface states forming an odd number of
surface bands that possesses unique electronic properties. However, transport
measurements have often been dominated by residual bulk carriers from crystal
defects or environmental doping which mask the topological surface
contribution. Here we demonstrate (BixSb1-x)2Te3 as a tunable topological
insulator system to manipulate bulk conductivity by varying the Bi/Sb
composition ratio. (BixSb1-x)2Te3 ternary compounds are confirmed as
topological insulators for the entire composition range by angle resolved
photoemission spectroscopy (ARPES) measurements and ab initio calculations.
Additionally, we observe a clear ambipolar gating effect similar to that
observed in graphene using nanoplates of (BixSb1-x)2Te3 in
field-effect-transistor (FET) devices. The manipulation of carrier type and
concentration in topological insulator nanostructures demonstrated in this
study paves the way for implementation of topological insulators in
nanoelectronics and spintronics.Comment: 7 pages, 4 figure
A microtubule interactome: complexes with roles in cell cycle and mitosis.
addresses: Department of Zoology, University of Oxford, Oxford, United Kingdom.notes: PMCID: PMC2323305types: Journal Article; Research Support, Non-U.S. Gov'tCopyright: © 2008 Hughes et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The microtubule (MT) cytoskeleton is required for many aspects of cell function, including the transport of intracellular materials, the maintenance of cell polarity, and the regulation of mitosis. These functions are coordinated by MT-associated proteins (MAPs), which work in concert with each other, binding MTs and altering their properties. We have used a MT cosedimentation assay, combined with 1D and 2D PAGE and mass spectrometry, to identify over 250 MAPs from early Drosophila embryos. We have taken two complementary approaches to analyse the cellular function of novel MAPs isolated using this approach. First, we have carried out an RNA interference (RNAi) screen, identifying 21 previously uncharacterised genes involved in MT organisation. Second, we have undertaken a bioinformatics analysis based on binary protein interaction data to produce putative interaction networks of MAPs. By combining both approaches, we have identified and validated MAP complexes with potentially important roles in cell cycle regulation and mitosis. This study therefore demonstrates that biologically relevant data can be harvested using such a multidisciplinary approach, and identifies new MAPs, many of which appear to be important in cell division
Two-dimensional Dirac fermions in a topological insulator: transport in the quantum limit
Pulsed magnetic fields of up to 55T are used to investigate the transport
properties of the topological insulator Bi_2Se_3 in the extreme quantum limit.
For samples with a bulk carrier density of n = 2.9\times10^16cm^-3, the lowest
Landau level of the bulk 3D Fermi surface is reached by a field of 4T. For
fields well beyond this limit, Shubnikov-de Haas oscillations arising from
quantization of the 2D surface state are observed, with the \nu =1 Landau level
attained by a field of 35T. These measurements reveal the presence of
additional oscillations which occur at fields corresponding to simple rational
fractions of the integer Landau indices.Comment: 5 pages, 4 figure
Branch facial nerve trauma after superficial temporal artery biopsy: a case report
<p>Abstract</p> <p>Introduction</p> <p>Giant cell arteritis is an emergency requiring prompt diagnosis and treatment. Superficial temporal artery biopsy is the gold diagnostic standard. Complications are few and infrequent; however, facial nerve injury has been reported, leaving an untoward cosmetic outcome. This case report is to the best of our knowledge only the fourth one presented in the available literature so far regarding facial nerve injury from superficial temporal artery biopsy.</p> <p>Case presentation</p> <p>A 73-year-old Caucasian woman presented for neurological evaluation regarding eyebrow and facial asymmetry after a superficial temporal artery biopsy for presumptive giant cell arteritis-induced cephalalgia.</p> <p>Conclusion</p> <p>Damage to branches of the facial nerve may occur after superficial temporal artery biopsy, resulting in eyebrow droop. Although an uncommon and sparsely reported complication, all clinicians of various specialties involved in the care of these patients should be aware of this given the gravity of giant cell arteritis and the widespread use of temporal artery biopsy.</p
Overdiagnosis and overtreatment of breast cancer: Rates of ductal carcinoma in situ: a US perspective
The incidence of breast ductal carcinoma in situ (DCIS) in the USA exceeds that of other countries. This cannot be explained entirely by the frequency of mammographic screening in the USA and may result from differences in the interpretation of mammograms and/or the frequency with which biopsies are obtained. Although the percentage of DCIS patients treated with mastectomy has decreased, the absolute number is unchanged and the use of lumpectomy with whole-breast radiotherapy has increased in inverse proportion to the decrease in mastectomy. Treatment of DCIS with tamoxifen is still limited
Quantum states made to measure
Recent progress in manipulating quantum states of light and matter brings
quantum-enhanced measurements closer to prospective applications. The current
challenge is to make quantum metrologic strategies robust against
imperfections.Comment: 4 pages, 3 figures, Commentary for Nature Photonic
- âŠ