931 research outputs found
Zeta Determinant for Laplace Operators on Riemann Caps
The goal of this paper is to compute the zeta function determinant for the
massive Laplacian on Riemann caps (or spherical suspensions). These manifolds
are defined as compact and boundaryless dimensional manifolds deformed by a
singular Riemannian structure. The deformed spheres, considered previously in
the literature, belong to this class. After presenting the geometry and
discussing the spectrum of the Laplacian, we illustrate a method to compute its
zeta regularized determinant. The special case of the deformed sphere is
recovered as a limit of our general formulas.Comment: 19 pages, 1 figur
Angle-dependent normalization of neutron-proton differential cross sections
Systematic errors in the database of differential cross sections below
350 MeV are studied. By applying angle-dependent normalizations with the help
of the energy-dependent Nijmegen partial-wave analysis PWA93 the
-values of some seriously flawed data sets can be reduced significantly
at the expense of a few degrees of freedom. It turns out that in these special
cases the renormalized data sets can be made statistically acceptable such that
they do not have to be discarded any longer in partial-wave analyses of the
two-nucleon scattering data.Comment: 11 pages, 1 figure; expanded versio
French women's experiences and opinions with in-country versus cross-border abortion travel: a mixed-methods paper
ObjectivesThis is the first study contrasting the experience of women residing in France and travelling for abortion services inside and outside their country of residence. We compare travel reasons and costs as well as our study participants' opinions of abortion legislation. The article documents legal and procedural barriers related to accessing local and timely abortions and provides policy recommendations to broaden care options. MethodsThe study is based on a mixed-methods research design. Quantitative data were descriptively analysed using Stata and drawn from 100 surveys with in-country abortion seekers collected from 3 Parisian hospitals, and 57 surveys with French residents seeking abortion care in the Netherlands (42), Spain (10) and the UK (5). Qualitative data were thematically analysed using ATLAS.ti and drawn from 36 interviews with French residents (23 in-country abortion seekers and 13 cross-border abortion travellers). FindingsGestational age (GA) limits were the key reason for cross-border travel, while lack of close-by, timely and good quality abortion care was the main driver for in-country abortion travel. Unlike in-country travellers, cross-border abortion seekers faced significant financial costs and burdens related to such travel. Partners, family members and service providers offered important support structures to both cross-border and in-country travellers. ConclusionsLegal time limits appeared to be the key driver for abortion-related travel of French residents. Having passed or being at risk of exceeding the GA limit caused women to travel outside their country or department of residence for abortion care
DBI Galileon inflation in background SUGRA
We introduce a model of potential driven DBI Galileon inflation in background
N=1,D=4 SUGRA. Starting from D4- brane-antibrane in the bulk N=2,D=5
SUGRA including quadratic Gauss-Bonnet corrections, we derive an effective
N=1,D=4 SUGRA by dimensional reduction, that results in a Coleman-Weinberg type
Galileon potential. We employ this potential in modeling inflation and in
subsequent study of primordial quantum fluctuations for scalar and tensor
modes. Further, we estimate the major observable parameters in both de Sitter
(DS) and beyond de Sitter (BDS) limits and confront them with recent
observational data from WMAP7 by using the publicly available code CAMB.Comment: 24 pages, 5 figures, Accepted for publication in Nuclear Physics
Web Data Extraction, Applications and Techniques: A Survey
Web Data Extraction is an important problem that has been studied by means of
different scientific tools and in a broad range of applications. Many
approaches to extracting data from the Web have been designed to solve specific
problems and operate in ad-hoc domains. Other approaches, instead, heavily
reuse techniques and algorithms developed in the field of Information
Extraction.
This survey aims at providing a structured and comprehensive overview of the
literature in the field of Web Data Extraction. We provided a simple
classification framework in which existing Web Data Extraction applications are
grouped into two main classes, namely applications at the Enterprise level and
at the Social Web level. At the Enterprise level, Web Data Extraction
techniques emerge as a key tool to perform data analysis in Business and
Competitive Intelligence systems as well as for business process
re-engineering. At the Social Web level, Web Data Extraction techniques allow
to gather a large amount of structured data continuously generated and
disseminated by Web 2.0, Social Media and Online Social Network users and this
offers unprecedented opportunities to analyze human behavior at a very large
scale. We discuss also the potential of cross-fertilization, i.e., on the
possibility of re-using Web Data Extraction techniques originally designed to
work in a given domain, in other domains.Comment: Knowledge-based System
Theorem on the Distribution of Short-Time Particle Displacements with Physical Applications
The distribution of the initial short-time displacements of particles is
considered for a class of classical systems under rather general conditions on
the dynamics and with Gaussian initial velocity distributions, while the
positions could have an arbitrary distribution. This class of systems contains
canonical equilibrium of a Hamiltonian system as a special case. We prove that
for this class of systems the nth order cumulants of the initial short-time
displacements behave as the 2n-th power of time for all n>2, rather than
exhibiting an nth power scaling. This has direct applications to the initial
short-time behavior of the Van Hove self-correlation function, to its
non-equilibrium generalizations the Green's functions for mass transport, and
to the non-Gaussian parameters used in supercooled liquids and glasses.Comment: A less ambiguous mathematical notation for cumulants was adopted and
several passages were reformulated and clarified. 40 pages, 1 figure.
Accepted by J. Stat. Phy
Evidence for biphasic uncoating during HIV-1 infection from a novel imaging assay
BACKGROUND: Uncoating of the HIV-1 core plays a critical role during early post-fusion stages of infection but is poorly understood. Microscopy-based assays are unable to easily distinguish between intact and partially uncoated viral cores.
RESULTS: In this study, we used 5-ethynyl uridine (EU) to label viral-associated RNA during HIV production. At early time points after infection with EU-labeled virions, the viral-associated RNA was stained with an EU-specific dye and was detected by confocal microscopy together with viral proteins. We observed that detection of the viral-associated RNA was specific for EU-labeled virions, was detected only after viral fusion with target cells, and occurred after an initial opening of the core. In vitro staining of cores showed that the opening of the core allowed the small molecule dye, but not RNase A or antibodies, inside. Also, staining of the viral-associated RNA, which is co-localized with nucleocapsid, decays over time after viral infection. The decay rate of RNA staining is dependent on capsid (CA) stability, which was altered by CA mutations or a small molecule inducer of HIV-1 uncoating. While the staining of EU-labeled RNA was not affected by inhibition of reverse transcription, the kinetics of core opening of different CA mutants correlated with initiation of reverse transcription. Analysis of the E45A CA mutant suggests that initial core opening is independent of complete capsid disassembly.
CONCLUSIONS: Taken together, our results establish a novel RNA accessibility-based assay that detects an early event in HIV-1 uncoating and can be used to further define this process
FunMap: Efficient Execution of Functional Mappings for Knowledge Graph Creation
Data has exponentially grown in the last years, and knowledge graphs
constitute powerful formalisms to integrate a myriad of existing data sources.
Transformation functions -- specified with function-based mapping languages
like FunUL and RML+FnO -- can be applied to overcome interoperability issues
across heterogeneous data sources. However, the absence of engines to
efficiently execute these mapping languages hinders their global adoption. We
propose FunMap, an interpreter of function-based mapping languages; it relies
on a set of lossless rewriting rules to push down and materialize the execution
of functions in initial steps of knowledge graph creation. Although applicable
to any function-based mapping language that supports joins between mapping
rules, FunMap feasibility is shown on RML+FnO. FunMap reduces data redundancy,
e.g., duplicates and unused attributes, and converts RML+FnO mappings into a
set of equivalent rules executable on RML-compliant engines. We evaluate FunMap
performance over real-world testbeds from the biomedical domain. The results
indicate that FunMap reduces the execution time of RML-compliant engines by up
to a factor of 18, furnishing, thus, a scalable solution for knowledge graph
creation
Charge-Asymmetry of the Nucleon-Nucleon Interaction
Based upon the Bonn meson-exchange model for the nucleon-nucleon ()
interaction, we study systematically the charge-symmetry-breaking (CSB) of the
interaction due to nucleon mass splitting. Particular attention is payed
to CSB generated by the -exchange contribution to the interaction,
diagrams, and other multi-meson-exchanges. We calculate the CSB
differences in the effective range parameters as well as phase shift
differences in , and higher partial waves up to 300 MeV lab. energy. We
find a total CSB difference in the singlet scattering length of 1.6 fm which
explains the empirical value accurately. The corresponding CSB phase-shift
differences are appreciable at low energy in the state. In the other
partial waves, the CSB splitting of the phase shifts is small and increases
with energy, with typical values in the order of 0.1 deg at 300 MeV in and
waves.Comment: 11 pages, RevTex, 14 figure
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