481 research outputs found

    Application of a rule-based knowledge system using CLIPS for the taxonomy of selected Opuntia species

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    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

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    We discuss the vacuum energy of a quantized scalar field in the presence of classical surfaces, defining bounded domains ΩRd\Omega \subset {\mathbb{R}}^{d}, 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 Ω=Rd1×[0,L]\Omega=\mathbb R^{d-1}\times[0, L] 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 L1L_{1} and L2L_{2}, i.e., Ω=[0,L1]×[0,L2]\Omega=[0,L_{1}]\times[0,L_{2}] 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

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    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

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    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

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    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

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    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 z0.8z\sim0.8 and over a volume of nearly 0.1~Gpc3^3. We use a unique combination of deep observations in the CFHTLenS/VIPERS field from the near-UV to the near-IR, supplemented by 60000\sim60\,000 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 Mh,peak=1.90.1+0.2×1012MM_{\rm h, peak} = 1.9^{+0.2}_{-0.1}\times10^{12} M_{\odot} with an amplitude of 0.0250.025, which decreases to 0.001\sim0.001 for massive halos (Mh>1014MM_{\rm h} > 10^{14} M_{\odot}). 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 z=1z=1: we find good general agreement, independently of the method used, within the typical stellar-mass systematic errors at low to intermediate mass (M<1011M{M}_{\star} < 10^{11} M_{\odot}) 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

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    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

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    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

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    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 (w0,wa)(w_0, w_a). 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 10510610^5-10^6 spectroscopic redshifts are needed for calibration of the full survey.Comment: 21 pages, accepted MNRA
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