26,979 research outputs found
Top pair cross section measurements at the LHC
The most recent results on the measurements of (tt) production and cross
sections at 7 TeV are presented. These are obtained using CMS [1] and ATLAS [2]
data collected in 2011. Recent results on the tt production cross section at 8
TeV using 2012 CMS data are also presented. The tt inclusive cross sections are
measured in the lepton+jets, dilepton and fully hadronic channels, including
the tau-dilepton and tau+jets modes. The results are combined and confronted
with precise theory calculations.Comment: Proceedings of CKM 2012, the 7th International Workshop on the CKM
Unitarity Triangle, University of Cincinnati, USA, 28 September - 2 October
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Reorganizing the hierarchy : issue salience and preferences among Latino national-origin groups
Political science has not adequately explored the many differences among Latino subgroups and what these differences may mean for policy preferences among Latinos in the aggregate. In this thesis, I seek to answer whether Latino subgroup identities have an effect on issue saliency and preferences and whether this effect remains relevant when accounting for the many socioeconomic and other factors that are thought to characterize Latino communities. I argue that Latino subgroup members have established goals and preferences that shape which issues they prioritize based upon their individual histories and interactions with U.S. policy. While a change in issue saliency may reorganize the hierarchy of preferences, it does not change the preferences themselves, just the attention given to an individual goal. These changes may appear to illustrate a stronger Latino solidarity overall and more homogenous opinion in terms of immigration policy, but they instead capture attention rather than the underlying established preferences among subgroups. This thesis constitutes a proposal to test this theoryGovernmen
A Random Force is a Force, of Course, of Coarse: Decomposing Complex Enzyme Kinetics with Surrogate Models
The temporal autocorrelation (AC) function associated with monitoring order
parameters characterizing conformational fluctuations of an enzyme is analyzed
using a collection of surrogate models. The surrogates considered are
phenomenological stochastic differential equation (SDE) models. It is
demonstrated how an ensemble of such surrogate models, each surrogate being
calibrated from a single trajectory, indirectly contains information about
unresolved conformational degrees of freedom. This ensemble can be used to
construct complex temporal ACs associated with a "non-Markovian" process. The
ensemble of surrogates approach allows researchers to consider models more
flexible than a mixture of exponentials to describe relaxation times and at the
same time gain physical information about the system. The relevance of this
type of analysis to matching single-molecule experiments to computer
simulations and how more complex stochastic processes can emerge from a mixture
of simpler processes is also discussed. The ideas are illustrated on a toy SDE
model and on molecular dynamics simulations of the enzyme dihydrofolate
reductase.Comment: 11 pages / 6 figure
Evolution of Communities with Focus on Stability
Community detection is an important tool for analyzing the social graph of
mobile phone users. The problem of finding communities in static graphs has
been widely studied. However, since mobile social networks evolve over time,
static graph algorithms are not sufficient. To be useful in practice (e.g. when
used by a telecom analyst), the stability of the partitions becomes critical.
We tackle this particular use case in this paper: tracking evolution of
communities in dynamic scenarios with focus on stability. We propose two
modifications to a widely used static community detection algorithm: we
introduce fixed nodes and preferential attachment to pre-existing communities.
We then describe experiments to study the stability and quality of the
resulting partitions on real-world social networks, represented by monthly call
graphs for millions of subscribers.Comment: AST at 42nd JAIIO, September 16-20, 2013, Cordoba, Argentina. arXiv
admin note: substantial text overlap with arXiv:1311.550
Infrastructure and growth in Africa
The goal of the paper is to provide a comprehensive assessment of the impact of infrastructure development on growth in African countries. Based on econometric estimates for a sample of 136 countries from 1960-2005, the authors evaluate the impact on per capita growth of faster accumulation of infrastructure stocks and of enhancement in the quality of infrastructure services for 39 African countries in three key infrastructure sectors: telecommunications, electricity, and roads. Using an econometric technique suitable for dynamic panel data models and likely endogenous regressors, the authors find that infrastructure stocks and service quality boost economic growth. The growth payoff of reaching the infrastructure development of the African leader (Mauritius) is 1.1 percent of GDP per year in North Africa and 2.3 percent in Sub-Saharan Africa, with most of the contribution coming from more, rather than better, infrastructure. Across Africa, infrastructure contributed 99 basis points to per capita economic growth, versus 68 points for other structural policies. Most of the contribution came from increases in stocks (89 basis points), versus quality improvements (10 basis points). The findings show that growth is positively affected by the volume of infrastructure stocks and the quality of infrastructure services; simulations show that our empirical findings are significant statistically and economically. Identifying areas of opportunity to generate productivity growth, the authors find that African countries are likely to gain more from larger stocks of infrastructure than from enhancements in the quality of existing infrastructure. The payoffs are largest for telephone density, electricity-generating capacity, road-network length, and road quality.Transport Economics Policy&Planning,Infrastructure Economics,E-Business,Private Participation in Infrastructure,Non Bank Financial Institutions
Effect of housing on rubber slat mats during pregnancy on the behaviour and welfare of sows in farrowing crates
peer-reviewedThe aim of this study was to evaluate the effect of flooring type during gestation,
lameness
and limb lesion scores on welfare and behaviour of sows in farrowing crates.
Sixty sows group-housed during gestation in pens with solid concrete floored feeding
stalls and a concrete, fully slatted group area either uncovered (CON; n = 30) or covered
with 10 mm thick rubber slat mats (RUB; n = 30) were transferred to the farrowing
crate at 110d of gestation (-5d). Lameness was scored on -5d and at weaning (28 d postfarrowing).
Limb lesions were scored on -5d, 24 h later (-4d), 3 to 5 days post farrowing
and at weaning (i.e., day 28 post farrowing). Sows were video recorded for 24 h on -5d,
after the last piglet was born (FARROW) and prior to weaning. Videos were sampled
every 10 min and an index of the proportion of time spent in different postures (standing
[S], ventral [VL] and lateral lying [LL] and total lying) and number of postural
changes was calculated. Median scores were calculated for limb lesions and classified
as ≤ median or > median. Postural data were tested for normality and analysed using
mixed model equations methodology. Flooring during gestation did not affect any of
the variables recorded in this study. However, RUB sows tended to make more postural
changes than CON sows (P = 0.10). Sows with swelling scores > median spent more time
LL (68.9 vs. 63.1 ± 2.19%; P < 0.05) and less time VL (19.9 vs. 25.8 ± 2.27%; P < 0.05)
than sows with swelling scores ≤ median. Time spent S and VL decreased and LL
increased at FARROW compared to -5d and prior to weaning (P < 0.01). We found no
effect of flooring type during gestation on welfare and behaviour in the farrowing crate.
Factors such as limb lesions and adaptation to confinement (i.e., time spent inside the farrowing crate) appeared to have a greater influence on sow welfare and behaviour in
farrowing crates than the flooring on which they were housed during gestation.This work was administered by Teagasc’s Walsh
Fellowship Scheme via funding from Enterprise
Ireland and EasyFix™ Rubber Products
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