2,669 research outputs found
New development: Directly elected mayors in Italy: creating a strong leader doesnât mean creating strong leadership
More than 20 years after their introduction, directly elected mayors are key players in Italian urban governance. This article explains the main effects of this reform on local government systems and provides lessons for other countries considering directly elected mayors
The practices of apartheid as a war crime: a critical analysis
The human suffering caused by the political ideology of apartheid in South Africa during the Apartheid era (1948-1994) prompted worldwide condemnation and a variety of diplomatic and legal responses. Amongst these responses was the attempt to have apartheid recognised both as a crime against humanity in the 1973 Apartheid Convention as well as a war crime in Article 85(4)(c) of Additional Protocol I. This article examines the origins, nature and current status of the practices of apartheid as a war crime and its possible application to the Israeli-Palestinian conflict
Portal venous gas after a failed endoscopic retrograde cholangiopancreatography attempt in a patient with a large hepatocellular carcinoma: A case report
The cause of hepatic portal vein gas (HPVG) is variable. Good knowledge of the possible causes, combined with the clinical assessment of the patient and a good quality imaging, is required to correctly identify the underlying cause of HPVG and to best predict the prognosis
Complex effective index in graphene-silicon waveguides
We report for the first time and characterize experimentally the complex optical
conductivity of graphene on silicon photonic waveguides. This permits us to predict
accurately the behavior of photonic integrated devices encompassing graphene layers.
Exploiting a Si microring add/drop resonator, we show the effect of electrical gating of
graphene on the complex effective index of the waveguide by measuring both the wavelength
shift of the resonance and the change in the drop peak transmission. Due to electro-refractive
effect of graphene a giant (>10 123) change in the effective index is demonstrated for the first
time on Si photonics waveguides and this large effect will crucially impact performances and
consumption of Si photonics devices. We confirmed the results by two independent
experiments involving two different gating schemes: Si gating through the ridge waveguide,
and polymer-electrolyte gating. Both the experiments demonstrate a very large phase effect in
good agreement with numerical calculations. The reported results validate the Kubo model
for the case of graphene-Si photonics interfaces and for propagation in this type of
waveguide. This is fundamental for the next design and fabrication of future graphene-silicon
photonics devices
Regulatory noncoding and predicted pathogenic coding variants of ccr5 predispose to severe covid-19
Genome-wide association studies (GWAS) found locus 3p21.31 associated with severe COVID-19. CCR5 resides at the same locus and, given its known biological role in other infection diseases, we investigated if common noncoding and rare coding variants, affecting CCR5, can predispose to severe COVID-19. We combined single nucleotide polymorphisms (SNPs) that met the suggestive significance level (P †1 Ă 10â5 ) at the 3p21.31 locus in public GWAS datasets (6406 COVID-19 hospitalized patients and 902,088 controls) with gene expression data from 208 lung tissues, Hi-C, and Chip-seq data. Through whole exome sequencing (WES), we explored rare coding variants in 147 severe COVID-19 patients. We identified three SNPs (rs9845542, rs12639314, and rs35951367) associated with severe COVID-19 whose risk alleles correlated with low CCR5 expression in lung tissues. The rs35951367 resided in a CTFC binding site that interacts with CCR5 gene in lung tissues and was confirmed to be associated with severe COVID-19 in two independent datasets. We also identified a rare coding variant (rs34418657) associated with the risk of developing severe COVID-19. Our results suggest a biological role of CCR5 in the progression of COVID-19 as common and rare genetic variants can increase the risk of developing severe COVID-19 by affecting the functions of CCR5
Robust pricing and hedging of double no-touch options
Double no-touch options, contracts which pay out a fixed amount provided an
underlying asset remains within a given interval, are commonly traded,
particularly in FX markets. In this work, we establish model-free bounds on the
price of these options based on the prices of more liquidly traded options
(call and digital call options). Key steps are the construction of super- and
sub-hedging strategies to establish the bounds, and the use of Skorokhod
embedding techniques to show the bounds are the best possible.
In addition to establishing rigorous bounds, we consider carefully what is
meant by arbitrage in settings where there is no {\it a priori} known
probability measure. We discuss two natural extensions of the notion of
arbitrage, weak arbitrage and weak free lunch with vanishing risk, which are
needed to establish equivalence between the lack of arbitrage and the existence
of a market model.Comment: 32 pages, 5 figure
Precise mirror alignment and basic performance of the RICH detector of the NA62 experiment at CERN
The Ring Imaging Cherenkov detector is crucial for the identification of
charged particles in the NA62 experiment at the CERN SPS. The detector
commissioning was completed in 2016 by the precise alignment of mirrors using
reconstructed tracks. The alignment procedure and measurement of the basic
performance are described. Ring radius resolution, ring centre resolution,
single hit resolution and mean number of hits per ring are evaluated for
positron tracks. The contribution of the residual mirror misalignment to the
performance is calculated.Comment: 13 pages, 10 figure
Muon Energy Estimate Through Multiple Scattering with the Macro Detector
Muon energy measurement represents an important issue for any experiment
addressing neutrino induced upgoing muon studies. Since the neutrino
oscillation probability depends on the neutrino energy, a measurement of the
muon energy adds an important piece of information concerning the neutrino
system. We show in this paper how the MACRO limited streamer tube system can be
operated in drift mode by using the TDC's included in the QTPs, an electronics
designed for magnetic monopole search. An improvement of the space resolution
is obtained, through an analysis of the multiple scattering of muon tracks as
they pass through our detector. This information can be used further to obtain
an estimate of the energy of muons crossing the detector. Here we present the
results of two dedicated tests, performed at CERN PS-T9 and SPS-X7 beam lines,
to provide a full check of the electronics and to exploit the feasibility of
such a multiple scattering analysis. We show that by using a neural network
approach, we are able to reconstruct the muon energy for 40 GeV. The
test beam data provide an absolute energy calibration, which allows us to apply
this method to MACRO data.Comment: 25 pages, 11 figures, Submitted to Nucl. Instr. & Meth.
Semilattices, Canonical Embeddings and Representing Measures
We provide conditions under which a modular function defined on a semilattice
and with values in a commutative group is homomorphic to a modular function
on a lattice for any embedding
Light Detection System and Time Resolution of the NA62 RICH
A large RICH detector is used in NA62 to suppress the muon contamination in
the charged pion sample by a factor of 100 in the momentum range between 15 and
35 GeV/c. Cherenkov light is collected by 1952 photomultipliers placed at the
upstream end. In this paper the characterization of the photomultipliers and
the dedicated Frontend and Data Acquisition electronics are described, the time
resolution and the light detection efficiency measurement are presented.Comment: 15 pages, 11 figure
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