484 research outputs found
Application of a rule-based knowledge system using CLIPS for the taxonomy of selected Opuntia species
A rule based knowledge system was developed in CLIPS (C Language Integrated Production System) for identifying Opuntia species in the family Cactaceae, which contains approx. 1500 different species. This botanist expert tool system is capable of identifying selected Opuntia plants from the family level down to the species level when given some basic characteristics of the plants. Many plants are becoming of increasing importance because of their nutrition and human health potential, especially in the treatment of diabetes mellitus. The expert tool system described can be extremely useful in an unequivocal identification of many useful Opuntia species
The vacuum energy with non-ideal boundary conditions via an approximate functional equation
We discuss the vacuum energy of a quantized scalar field in the presence of
classical surfaces, defining bounded domains ,
where the field satisfies ideal or non-ideal boundary conditions. For the
electromagnetic case, this situation describes the conductivity correction to
the zero-point energy. Using an analytic regularization procedure, we obtain
the vacuum energy for a massless scalar field at zero temperature in the
presence of a slab geometry with Dirichlet
boundary conditions. To discuss the case of non-ideal boundary conditions, we
employ an asymptotic expansion, based on an approximate functional equation for
the Riemann zeta-function, where finite sums outside their original domain of
convergence are defined. Finally, to obtain the Casimir energy for a massless
scalar field in the presence of a rectangular box, with lengths and
, i.e., with non-ideal boundary
conditions, we employ an approximate functional equation of the Epstein
zeta-function.Comment: 10 page
Very weak lensing in the CFHTLS Wide: Cosmology from cosmic shear in the linear regime
We present an exploration of weak lensing by large-scale structure in the
linear regime, using the third-year (T0003) CFHTLS Wide data release. Our
results place tight constraints on the scaling of the amplitude of the matter
power spectrum sigma_8 with the matter density Omega_m. Spanning 57 square
degrees to i'_AB = 24.5 over three independent fields, the unprecedented
contiguous area of this survey permits high signal-to-noise measurements of
two-point shear statistics from 1 arcmin to 4 degrees. Understanding systematic
errors in our analysis is vital in interpreting the results. We therefore
demonstrate the percent-level accuracy of our method using STEP simulations, an
E/B-mode decomposition of the data, and the star-galaxy cross correlation
function. We also present a thorough analysis of the galaxy redshift
distribution using redshift data from the CFHTLS T0003 Deep fields that probe
the same spatial regions as the Wide fields. We find sigma_8(Omega_m/0.25)^0.64
= 0.785+-0.043 using the aperture-mass statistic for the full range of angular
scales for an assumed flat cosmology, in excellent agreement with WMAP3
constraints. The largest physical scale probed by our analysis is 85 Mpc,
assuming a mean redshift of lenses of 0.5 and a LCDM cosmology. This allows for
the first time to constrain cosmology using only cosmic shear measurements in
the linear regime. Using only angular scales theta> 85 arcmin, we find
sigma_8(Omega_m/0.25)_lin^0.53 = 0.837+-0.084, which agree with the results
from our full analysis. Combining our results with data from WMAP3, we find
Omega_m=0.248+-0.019 and sigma_8 = 0.771+-0.029.Comment: 23 pages, 16 figures (A&A accepted
Prednisone and azathioprine in patients with inflammatory cardiomyopathy: systematic review and meta-analysis
Aims: Chronic non-viral myocarditis, also called inflammatory cardiomyopathy, can be treated with immune suppression on tops of optimal medical therapy (OMT) for heart failure, using a combination of prednisolone and azathioprine (IPA). However, there has been inconsistency in the effects of immunosuppression treatment. This meta-analysis is the first to evaluate all available data of the effect of this treatment on left ventricular ejection fraction (LVEF) and the combined clinical endpoint of cardiovascular mortality and/or heart transplantation-free survival. Methods and results: All trials with using IPA vs. OMT in this syndrome were searched using OVID Medline and ClinicalTrials. gov, following the PRISMA guidelines. Missing data were retrieved after contacting the corresponding authors. All data was reviewed and analysed using and standard meta-analysis methods. A random effect model was used to pool the effect sizes. A total of four trials (three randomised controlled trials and one propensity-matched retrospective registry) including 369 patients were identified. IPA on top of OMT did not improve LVEF [mean difference 9.9% (95% confidence interval -1.8, 21.7)] with significant heterogeneity. When we limited our pooled estimate to the published studies only, significant LVEF improvement by IPA was observed [14% (1.4, 26.6)]. No cardiovascular mortality benefit was observed with the intervention [risk ratio 0.34 (0.08, 1.51)]. Conclusions: At the moment, there is insufficient evidence supporting functional and prognostic benefits of IPA added to OMT in virus negative inflammatory positive cardiomyopathy. Further adequate-powered well-designed prospective RCTs should be warranted to explore the potential effects of adding immunosuppressive therapy to OMT
Multifactorial evaluation and treatment of persons with a high risk of recurrent falling was not cost-effective
This study evaluated the cost-effectiveness of multifactorial evaluation and treatment of fall risk factors in community-dwelling older persons at high risk of falling. The intervention and usual care groups did not differ in fall risk or costs. The multifactorial approach was not cost-effective compared to usual care in this group. Introduction: International guidelines recommend multifactorial evaluation and tailored treatment of risk factors to reduce falling in older persons. The cost-effectiveness may be enhanced in high-risk persons. Our study evaluates the cost-effectiveness of multifactorial evaluation and treatment of fall risk factors in community-dwelling older persons at high risk of recurrent falling. Methods: An economic evaluation was conducted alongside a randomised controlled trial. Participants (≥65 years) with a high risk of recurrent falling were randomised into an intervention (n=106) and usual care group (n=111). The intervention consisted of multifactorial assessment and treatment of fall risk factors. Clinical outcomes were proportions of fallers and utility during 1 year. Costs were measured using questionnaires at 3, 6 and 12 months after baseline and valued using cost prices, if available, and guideline prices. Differences in costs and cost-effectiveness were analysed using bootstrapping. Cost-effectiveness planes and acceptability curves were presented. Results: During 1 year, 52% and 56% of intervention and usual care participants reported at least one fall, respectively. The clinical outcome measures did not differ between the two groups. The mean costs were Euro 7,740 (SD 9,129) in the intervention group and Euro 6,838 (SD 8,623) in the usual care group (mean difference Euro 902, bootstrapped 95% CI: -1,534 to 3,357). Cost-effectiveness planes and acceptability curves indicated that multifactorial evaluation and treatment of fall risk factors was not cost-effective compared with usual care. Conclusions: Multifactorial evaluation and treatment of persons with a high risk of recurrent falling was not cost-effective compared to usual care
The galaxy-halo connection from a joint lensing, clustering and abundance analysis in the CFHTLenS/VIPERS field
We present new constraints on the relationship between galaxies and their
host dark matter halos, measured from the location of the peak of the
stellar-to-halo mass ratio (SHMR), up to the most massive galaxy clusters at
redshift and over a volume of nearly 0.1~Gpc. We use a unique
combination of deep observations in the CFHTLenS/VIPERS field from the near-UV
to the near-IR, supplemented by secure spectroscopic redshifts,
analysing galaxy clustering, galaxy-galaxy lensing and the stellar mass
function. We interpret our measurements within the halo occupation distribution
(HOD) framework, separating the contributions from central and satellite
galaxies. We find that the SHMR for the central galaxies peaks at with an amplitude of ,
which decreases to for massive halos (). Compared to central galaxies only, the total SHMR (including
satellites) is boosted by a factor 10 in the high-mass regime (cluster-size
halos), a result consistent with cluster analyses from the literature based on
fully independent methods. After properly accounting for differences in
modelling, we have compared our results with a large number of results from the
literature up to : we find good general agreement, independently of the
method used, within the typical stellar-mass systematic errors at low to
intermediate mass () and the statistical
errors above. We have also compared our SHMR results to semi-analytic
simulations and found that the SHMR is tilted compared to our measurements in
such a way that they over- (under-) predict star formation efficiency in
central (satellite) galaxies.Comment: 31 pages, 18 figures, 4 table. Accepted for publication in MNRAS.
Online material available at http://www.cfhtlens.or
Clipping the Cosmos: The Bias and Bispectrum of Large Scale Structure
A large fraction of the information collected by cosmological surveys is
simply discarded to avoid lengthscales which are difficult to model
theoretically. We introduce a new technique which enables the extraction of
useful information from the bispectrum of galaxies well beyond the conventional
limits of perturbation theory. Our results strongly suggest that this method
increases the range of scales where the relation between the bispectrum and
power spectrum in tree-level perturbation theory may be applied, from k_max ~
0.1 h/Mpc to ~ 0.7 h/Mpc. This leads to correspondingly large improvements in
the determination of galaxy bias. Since the clipped matter power spectrum
closely follows the linear power spectrum, there is the potential to use this
technique to probe the growth rate of linear perturbations and confront
theories of modified gravity with observation.Comment: 5 pages, 2 figures. To appear in Physical Review Letter
A filament of dark matter between two clusters of galaxies
It is a firm prediction of the concordance Cold Dark Matter (CDM)
cosmological model that galaxy clusters live at the intersection of large-scale
structure filaments. The thread-like structure of this "cosmic web" has been
traced by galaxy redshift surveys for decades. More recently the Warm-Hot
Intergalactic Medium (WHIM) residing in low redshift filaments has been
observed in emission and absorption. However, a reliable direct detection of
the underlying Dark Matter skeleton, which should contain more than half of all
matter, remained elusive, as earlier candidates for such detections were either
falsified or suffered from low signal-to-noise ratios and unphysical
misalignements of dark and luminous matter. Here we report the detection of a
dark matter filament connecting the two main components of the Abell 222/223
supercluster system from its weak gravitational lensing signal, both in a
non-parametric mass reconstruction and in parametric model fits. This filament
is coincident with an overdensity of galaxies and diffuse, soft X-ray emission
and contributes mass comparable to that of an additional galaxy cluster to the
total mass of the supercluster. Combined with X-ray observations, we place an
upper limit of 0.09 on the hot gas fraction, the mass of X-ray emitting gas
divided by the total mass, in the filament.Comment: Nature, in pres
Photo-z for weak lensing tomography from space: the role of optical and near-IR photometry
We study in detail the photometric redshift requirements needed for
tomographic weak gravitational lensing in order to measure accurately the Dark
Energy equation of state. In particular, we examine how ground-based photometry
(u,g,r,i,z,y) can be complemented by space-based near-infrared (IR) photometry
(J,H), e.g. on board the planned DUNE satellite. Using realistic photometric
redshift simulations and an artificial neural network photo-z method we
evaluate the Figure of Merit for the Dark Energy parameters . We
consider a DUNE-like broad optical filter supplemented with ground-based
multi-band optical data from surveys like the Dark Energy Survey, Pan-STARRS
and LSST. We show that the Dark Energy Figure of Merit would improved by a
factor of 1.3 to 1.7 if IR filters are added on board DUNE. Furthermore we show
that with IR data catastrophic photo-z outliers can be removed effectively.
There is an interplay between the choice of filters, the magnitude limits and
the removal of outliers. We draw attention to the dependence of the results on
the galaxy formation scenarios encoded into the mock galaxies, e.g the galaxy
reddening. For example, deep u band data could be as effective as the IR. We
also find that about spectroscopic redshifts are needed for
calibration of the full survey.Comment: 21 pages, accepted MNRA
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