50,910 research outputs found
The Great Divide: Ruralisation of Poverty in Russia
Using data from the RLMS for the period 2000-2004 we investigate poverty trends in Russia. We find that urban poverty declines at twice the rate of rural poverty so that by 2004 poverty in Russia had become a largely rural phenomenon for the first time since transition began. This finding does not stem from changing population characteristics or shares, is not dependent on the use of a particular poverty line nor is it driven by the rapid expansions that have occurred in Moscow, St. Petersburg or other urban areas. Our findings flesh out those of Ravallion et al (2007) who, in contrast to other regions, "find signs" of a ruralisation of poverty in Eastern Europe and the Former Soviet Union. We attribute some of the differential to the labour market
Orthogonal nets and Clifford algebras
A Clifford algebra model for M"obius geometry is presented. The notion of
Ribaucour pairs of orthogonal systems in arbitrary dimensions is introduced,
and the structure equations for adapted frames are derived. These equations are
discretized and the geometry of the occuring discrete nets and sphere
congruences is discussed in a conformal setting. This way, the notions of
``discrete Ribaucour congruences'' and ``discrete Ribaucour pairs of orthogonal
systems'' are obtained --- the latter as a generalization of discrete
orthogonal systems in Euclidean space. The relation of a Cauchy problem for
discrete orthogonal nets and a permutability theorem for the Ribaucour
transformation of smooth orthogonal systems is discussed.Comment: Plain TeX, 16 pages, 4 picture
Modeling pedestrian evacuation movement in a swaying ship
With the advance in living standard, cruise travel has been rapidly expanding
around the world in recent years. The transportation of passengers in water has
also made a rapid development. It is expected that ships will be more and more
widely used. Unfortunately, ship disasters occurred in these years caused
serious losses. It raised the concern on effectiveness of passenger evacuation
on ships. The present study thus focuses on pedestrian evacuation features on
ships. On ships, passenger movements are affected by the periodical water
motion and thus are quite different from the characteristic when walking on
static horizontal floor. Taking into consideration of this special feature, an
agent-based pedestrian model is formulized and the effect of ship swaying on
pedestrian evacuation efficiency is investigated. Results indicated that the
proposed model can be used to quantify the special evacuation process on ships.Comment: Traffic and Granular Flow'15, At Delft, the Netherland
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Directing Selectivity of Electrochemical Carbon Dioxide Reduction Using Plasmonics
Catalysts for electrochemical carbon dioxide reduction in aqueous electrolytes suffer from high energy input requirements, competition with hydrogen evolution from water reduction, and low product selectivity. Theory suggests that plasmonic catalysts can be tuned to selectively lower the energy barrier for a specific reaction in a set of competitive reactions, but there has been little experimental evidence demonstrating plasmon-driven selectivity in complicated multielectron electrochemical processes. Here, the photoactivity at a plasmonically active silver thin film electrode at small cathodic potentials selectively generates carbon monoxide while simultaneously suppressing hydrogen production. At larger cathodic potentials, the photoactivity promotes production of methanol and formate. Methanol production is observed only under illumination, not in dark conditions. The preference of the plasmonic activity for carbon dioxide reduction over hydrogen evolution and the ability to tune plasmonic activity with voltage demonstrates that plasmonics provide a promising approach to promote complex electrochemical reactions over other competing reactions
Subsquares Approach - Simple Scheme for Solving Overdetermined Interval Linear Systems
In this work we present a new simple but efficient scheme - Subsquares
approach - for development of algorithms for enclosing the solution set of
overdetermined interval linear systems. We are going to show two algorithms
based on this scheme and discuss their features. We start with a simple
algorithm as a motivation, then we continue with a sequential algorithm. Both
algorithms can be easily parallelized. The features of both algorithms will be
discussed and numerically tested.Comment: submitted to PPAM 201
Star forming regions of the southern galaxy
A catalog of southern dust cloud properties is being compiled to aid in the planning and analysis of radio spectral line surveys in the southern hemisphere. Ultimately, images of dust temperature and column density will be produced. For the interim, a list of the 60 and 100 micron fluxes was prepared for the cores and adjacent backgrounds of 65 prominent dust clouds. Dust temperatures and column densities were derived
On local structures of cubicity 2 graphs
A 2-stab unit interval graph (2SUIG) is an axes-parallel unit square
intersection graph where the unit squares intersect either of the two fixed
lines parallel to the -axis, distance ()
apart. This family of graphs allow us to study local structures of unit square
intersection graphs, that is, graphs with cubicity 2. The complexity of
determining whether a tree has cubicity 2 is unknown while the graph
recognition problem for unit square intersection graph is known to be NP-hard.
We present a polynomial time algorithm for recognizing trees that admit a 2SUIG
representation
CRISPR evolution and bacteriophage persistence in the context of population bottlenecks
This is the author accepted manuscript. The final version is available from RNA Biology via the DOI in this recordPopulation bottlenecks often cause strong reductions in genetic diversity and alter population structure. In the context of host-parasite interactions, bottlenecks could in theory benefit either the host or the pathogen. We predicted that bottlenecking of bacterial populations that evolve CRISPR immunity against bacteriophages (phage) would benefit the pathogen, because CRISPR spacer diversity can rapidly drive phages extinct. To test this, we bottlenecked populations of bacteria and phage, tracking phage persistence and the evolution of bacterial resistance mechanisms. Contrary to our prediction, bottlenecking worked in the advantage of the host. With some possible exceptions, this effect was not caused by CRISPR immunity. This host benefit is consistent with a dilution effect disproportionately affecting phage. This study provides further insight into how bottlenecking influences bacteria-phage dynamics, the role of dilution in bacteria-phage interactions, and the evolution of host immune systems.South West Biosciences Doctoral Training PartnershipWellcome TrustNatural Environment Research CouncilBBSRCEuropean Research Counci
An analytic solution to the Busemann-Petty problem on sections of convex bodies
We derive a formula connecting the derivatives of parallel section functions
of an origin-symmetric star body in R^n with the Fourier transform of powers of
the radial function of the body. A parallel section function (or
(n-1)-dimensional X-ray) gives the ((n-1)-dimensional) volumes of all
hyperplane sections of the body orthogonal to a given direction. This formula
provides a new characterization of intersection bodies in R^n and leads to a
unified analytic solution to the Busemann-Petty problem: Suppose that K and L
are two origin-symmetric convex bodies in R^n such that the ((n-1)-dimensional)
volume of each central hyperplane section of K is smaller than the volume of
the corresponding section of L; is the (n-dimensional) volume of K smaller than
the volume of L? In conjunction with earlier established connections between
the Busemann-Petty problem, intersection bodies, and positive definite
distributions, our formula shows that the answer to the problem depends on the
behavior of the (n-2)-nd derivative of the parallel section functions. The
affirmative answer to the Busemann-Petty problem for n\le 4 and the negative
answer for n\ge 5 now follow from the fact that convexity controls the second
derivatives, but does not control the derivatives of higher orders.Comment: 13 pages, published versio
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