214,711 research outputs found
The slimming effect of advection on black-hole accretion flows
At super-Eddington rates accretion flows onto black holes have been described
as slim (aspect ratio ) or thick (H/R >1) discs, also known as
tori or (Polish) doughnuts. The relation between the two descriptions has never
been established, but it was commonly believed that at sufficiently high
accretion rates slim discs inflate, becoming thick. We wish to establish under
what conditions slim accretion flows become thick. We use analytical equations,
numerical 1+1 schemes, and numerical radiative MHD codes to describe and
compare various accretion flow models at very high accretion rates.We find that
the dominant effect of advection at high accretion rates precludes slim discs
becoming thick. At super-Eddington rates accretion flows around black holes can
always be considered slim rather than thick.Comment: 8 pages, 5 figures. Astronomy & Astrophysics, in pres
Slim SUSY
The new SM-like Higgs boson discovered recently at the LHC, with mass 125 GeV, as well as the direct LHC bounds on the mass of superpartners,
which are entering into the TeV range, suggest that the minimal surviving
supersymmetric extension of the SM (MSSM), should be characterized by a heavy
SUSY-breaking scale. Several variants of the MSSM have been proposed to account
for this result, which vary according to the accepted degree of fine-tuning. We
propose an alternative scenario here, Slim SUSY, which contains sfermions with
multi-TeV masses and gauginos/higgsinos near the EW scale, but it includes the
heavy MSSM Higgs bosons (, , ) near the EW scale too. We
discuss first the formulation and constraints of the Slim SUSY scenario, and
then identify distinctive heavy Higgs signals that could be searched at the
LHC, within scenarios with the minimal number of superpartners with masses near
the EW scale.Comment: 16 pages, 6 figures. Section 2 has been restructured, with a new
subsection and some comments added. This version matches the manuscript
accepted in Physics Letters
Supersparse Linear Integer Models for Optimized Medical Scoring Systems
Scoring systems are linear classification models that only require users to
add, subtract and multiply a few small numbers in order to make a prediction.
These models are in widespread use by the medical community, but are difficult
to learn from data because they need to be accurate and sparse, have coprime
integer coefficients, and satisfy multiple operational constraints. We present
a new method for creating data-driven scoring systems called a Supersparse
Linear Integer Model (SLIM). SLIM scoring systems are built by solving an
integer program that directly encodes measures of accuracy (the 0-1 loss) and
sparsity (the -seminorm) while restricting coefficients to coprime
integers. SLIM can seamlessly incorporate a wide range of operational
constraints related to accuracy and sparsity, and can produce highly tailored
models without parameter tuning. We provide bounds on the testing and training
accuracy of SLIM scoring systems, and present a new data reduction technique
that can improve scalability by eliminating a portion of the training data
beforehand. Our paper includes results from a collaboration with the
Massachusetts General Hospital Sleep Laboratory, where SLIM was used to create
a highly tailored scoring system for sleep apnea screeningComment: This version reflects our findings on SLIM as of January 2016
(arXiv:1306.5860 and arXiv:1405.4047 are out-of-date). The final published
version of this articled is available at http://www.springerlink.co
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The SLIM (Social learning for the integrated management and sustainable use of water at catchment scale) Final Report
Background: SLIM stands for 'Socuak Learning for the Integrated Management and Sustainable Use of Water at Catchment Scale'. It is a multi-country research project funded by the European Commission (DG RESEARCH - 5th Framework Programme for research and technological development, 1998-2002). Its main theme is the investigation of the socio-economic aspects of the sustainable use of water. Within this theme, its main focus of interest lies in understanding the application of social learning as a conceptual framework, an operational principle, a policy instrument and a process of systemic change
Sparse Linear Identifiable Multivariate Modeling
In this paper we consider sparse and identifiable linear latent variable
(factor) and linear Bayesian network models for parsimonious analysis of
multivariate data. We propose a computationally efficient method for joint
parameter and model inference, and model comparison. It consists of a fully
Bayesian hierarchy for sparse models using slab and spike priors (two-component
delta-function and continuous mixtures), non-Gaussian latent factors and a
stochastic search over the ordering of the variables. The framework, which we
call SLIM (Sparse Linear Identifiable Multivariate modeling), is validated and
bench-marked on artificial and real biological data sets. SLIM is closest in
spirit to LiNGAM (Shimizu et al., 2006), but differs substantially in
inference, Bayesian network structure learning and model comparison.
Experimentally, SLIM performs equally well or better than LiNGAM with
comparable computational complexity. We attribute this mainly to the stochastic
search strategy used, and to parsimony (sparsity and identifiability), which is
an explicit part of the model. We propose two extensions to the basic i.i.d.
linear framework: non-linear dependence on observed variables, called SNIM
(Sparse Non-linear Identifiable Multivariate modeling) and allowing for
correlations between latent variables, called CSLIM (Correlated SLIM), for the
temporal and/or spatial data. The source code and scripts are available from
http://cogsys.imm.dtu.dk/slim/.Comment: 45 pages, 17 figure
Search for strange quark matter and Q-balls with the SLIM experiment
We report on the search for Strange Quark Matter (SQM) and charged Q-balls
with the SLIM experiment at the Chacaltaya High Altitude Laboratory (5230 m
a.s.l.) from 2001 to 2005. The SLIM experiment was a 427 m array of
Nuclear Track Detectors (NTDs) arranged in modules of cm
area. SLIM NTDs were exposed to the cosmic radiation for 4.22 years after which
they were brought back to the Bologna Laboratory where they were etched and
analyzed. We estimate the properties and energy losses in matter of nuclearites
(large SQM nuggets), strangelets (small charged SQM nuggets) and Q-balls; and
discuss their detection with the SLIM experiment. The flux upper limits in the
CR of such downgoing particles are at the level of /cm/s/sr
(90% CL).Comment: 4 pages, 7 eps figures. Talk given at the 24th International
Conference on Nuclear Tracks in Solids, Bologna, Italy, 1-5 September 200
Analisis Pengaruh Brand Equity Terhadap Keputusan Pembelian Konsumen Pada Produk Gula Tropicana Slim Di Palembang
This research aims to test the influence of brand equity towards decision
purchase consumers on product Tropicana Slim in Palembang. Variable brand
equity is divided into four, namely brand awareness, brand loyalty, brand
association, and perceive quality. Analysis techniques were used, namely the
validity of the test, test, test the reliability of classical assumptions (test test,
multicollinearity, normality and test heterokedastisitas), multiple linear
regression test, t-test and F-test statistics, test results showed variable. brand
awareness, brand loyalty, and brand association does not affect consumer
purchasing decisions at Tropicana products Slim in Palembang. Variable
perceive quality shows that there is an impact on consumer purchasing decisions
at Tropicana products Slim in Palembang
New constructions of two slim dense near hexagons
We provide a geometrical construction of the slim dense near hexagon with
parameters . Using this construction, we construct
the rank 3 symplectic dual polar space which is the slim dense near
hexagon with parameters . Both the near hexagons are
constructed from two copies of a generalized quadrangle with parameters (2,2)
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