1,160 research outputs found
Substructure recovery by 3D Discrete Wavelet Transforms
We present and discuss a method to identify substructures in combined
angular-redshift samples of galaxies within Clusters. The method relies on the
use of Discrete Wavelet Transform (hereafter DWT) and has already been applied
to the analysis of the Coma cluster (Gambera et al. 1997). The main new
ingredient of our method with respect to previous studies lies in the fact that
we make use of a 3D data set rather than a 2D. We test the method on mock
cluster catalogs with spatially localized substructures and on a N-body
simulation. Our main conclusion is that our method is able to identify the
existing substructures provided that: a) the subclumps are detached in part or
all of the phase space, b) one has a statistically significant number of
redshifts, increasing as the distance decreases due to redshift distortions; c)
one knows {\it a priori} the scale on which substructures are to be expected.
We have found that to allow an accurate recovery we must have both a
significant number of galaxies ( for clusters at z or
about 800 at z 0.4) and a limiting magnitude for completeness .
The only true limitation to our method seems to be the necessity of knowing
{\it a priori} the scale on which the substructure is to be found. This is an
intrinsic drawback of the method and no improvement in numerical codes based on
this technique could make up for it.Comment: Accepted for publication in MNRAS. 7 pages, 2 figure
A discrimination technique for extensive air showers based on multiscale, lacunarity and neural network analysis
We present a new method for the identification of extensive air showers initiated by different primaries. The method uses the multiscale concept and is based on the analysis of multifractal behaviour and lacunarity of secondary particle distributions together with a properly designed and trained artificial neural network. In the present work the method is discussed and applied to a set of fully simulated vertical showers, in the experimental framework of ARGO-YBJ, to obtain hadron to gamma primary separation. We show that the presented approach gives very good results, leading, in the 1–10 TeV energy range, to a clear improvement of the discrimination power with respect to the existing figures for extended shower detectors
Properties of galaxy halos in Clusters and Voids
We use the results of a high resolution N-body simulation to investigate the
role of the environment on the formation and evolution of galaxy-sized halos.
Starting from a set of constrained initial conditions, we have produced a final
configuration hosting a double cluster in one octant and a large void extending
over two octants of the simulation box. We present results for two statistics:
the relationship between 1-D velocity dispersion and mass and the probability
distribution of the spin parameter . The \svm relationship is well
reproduced by the Truncated Isothermal Sphere (TIS) model introduced by Shapiro
et al. (1999), although the slope is different from the original prediction. A
series of \svm relationships for different values of the anisotropy parameter
, obtained using the theoretical predictions by Lokas and Mamon (2001)
for NFW density profiles are found to be only marginally consistent with the
data. Using some properties of the equilibrium TIS models, we construct
subsamples of {\em fiducial} equilibrium TIS halos from each of the three
subregions, and we study their properties. For these halos, we do find an
environmental dependence of their properties, in particular of the spin
parameter distribution . We study in more detail the TIS model, and
we find new relationships between the truncation radius and other structural
parameters. No gravitationally bound halo is found having a radius larger than
the critical value for gravithermal instability for TIS halos (\rt , where is the core radius of the TIS solution). We do however
find a dependence of this relationship on the environment, like for the
statistics. These facts hint at a possible r\^{o}le of tidal
fields at determining the statistical properties of halos.Comment: 12 pages, 14 figures. Accepted by MNRAS. Adopted an improved
algorithm for halo finding and added a comparison with NFW model
A multiscale method for gamma/h discrimination in extensive air showers
We present a new method for the identification of extensive air showers initiated by different primaries. The method uses the multiscale concept and is based on the analysis of multifractal behaviour and lacunarity of secondary particle distributions together with a properly designed and trained artificial neural network. The separation technique is
particularly suited for being applied when the topology of the particle distribution in the shower front is as largely detailed as possible. Here, our method is discussed and applied to a set of fully simulated vertical showers in the experimental framework of ARGO-YBJ, taking advantage of both the space and time distribution of the detected secondary particles in the shower front, to obtain hadron to gamma primary separation in EAS analysis. We show that the presented approach gives very good results, leading, in the 1-10 Tev energy range, to an improvement of the discrimination power with respect to the existing figures for extended shower detectors. The technique shows up to be very promising and its application may have important astrophysical prospects in different experimental environment of extended air shower study
Effects of physical exercise on cardiovascular diseases: Biochemical, cellular, and organ effects
Two Sides of the Same Coin: Environmental and Health Concern Pathways Toward Meat Consumption
The dramatic increase of meat production in the last decades has proven to be one of the most impacting causes of negative environmental outcomes (e.g., increase of greenhouse emissions, pollution of land and water, and biodiversity loss). In two studies, we aimed to verify the role of key socio-psychological dimensions on meat intake. Study 1 (N = 198) tested the predictive power of an extended version of the Value-Belief-Norm (VBN) model on individual food choices in an online supermarket simulation. In an online survey, participants were directed to a virtual shop and asked to buy food within a set amount of money. Subsequently, they completed measures of behavioral intention, the VBN constructs (values, general pro-environmental beliefs, awareness of consequences, ascription of responsibility, and personal norm), and social norms (injunctive and descriptive). The outcome variable was operationalized in terms of percentage of expenses dedicated to meat and processed meat items, which provided a more robust behavioral measure than the common self-reported ones. Results confirmed the VBN sequential path, showing direct effects of biospheric values and descriptive norm on personal norm. Furthermore, a proof of validity for the new behavioral measure was provided (medium-sized correlation with behavioral intention). Study 2 (N = 218) aimed at verifying whether the meat consumption could be also motivated by a health concern, reflecting individual (cost/benefit) considerations, besides pro-environmental drivers. Results showed the direct impact of health concern and confirmed the indirect role of biospheric values and descriptive norm (via personal norm) on meat intake. This evidence would suggest the use of multiple-frame messages, highlighting both pro-environmental and health consequences, for meat consumption reduction. Nevertheless, the different implications of moral (e.g., environmental concern) vs. non-moral motivators (e.g., health concern) for reducing meat intake need to be stressed: indeed, the first drivers are more central for self-identity and for engaging in environmental citizenship behaviors
Lentil fortified spaghetti: Technological properties and nutritional characterization
Lentil (Lens culinaris), consumed as a part of the diet worldwide, is a functional dietary ingredient that plays a function in human nutrition as a rich source of bioactive nutrients (low quantities of fat, sodium, and vitamin K; high content of potassium, essential amino acids, insoluble dietary fiber, and polyphenols). In this study spaghetti fortified with lentil flours (40% w/w) were developed and characterized. The addition of two different lentil flours significantly affected the sensory attributes and cooking properties of dry spaghetti. Therefore, the addition of carboxymethyl cellulose was adopted as technological option to improve the quality of fortified pasta; specifically, sensory acceptability, cooking loss, swelling index, and water absorption were studied. Chemical results highlighted that the addition of lentil to semolina significantly increased the content of lysine and threonine. It was observed an increase in essential and branched-chain amino acids. Contrary to what was expected, no increase in mono and polyunsaturated fatty acids was observed in fortified spaghetti, due to their loss during cooking, even after the addition of carboxymethyl cellulose
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