149 research outputs found

    Measuring the transition to homogeneity with photometric redshift surveys

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    We study the possibility of detecting the transition to homogeneity using photometric redshift catalogs. Our method is based on measuring the fractality of the projected galaxy distribution, using angular distances, and relies only on observable quantites. It thus provides a way to test the Cosmological Principle in a model-independent unbiased way. We have tested our method on different synthetic inhomogeneous catalogs, and shown that it is capable of discriminating some fractal models with relatively large fractal dimensions, in spite of the loss of information due to the radial projection. We have also studied the influence of the redshift bin width, photometric redshift errors, bias, non-linear clustering, and surveyed area, on the angular homogeneity index H2 ({\theta}) in a {\Lambda}CDM cosmology. The level to which an upcoming galaxy survey will be able to constrain the transition to homogeneity will depend mainly on the total surveyed area and the compactness of the surveyed region. In particular, a Dark Energy Survey (DES)-like survey should be able to easily discriminate certain fractal models with fractal dimensions as large as D2 = 2.95. We believe that this method will have relevant applications for upcoming large photometric redshift surveys, such as DES or the Large Synoptic Survey Telescope (LSST).Comment: 14 pages, 14 figure

    The Λ\LambdaCDM growth rate of structure revisited

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    We re-examine the growth index of the concordance Λ\Lambda cosmology in the light of the latest 6dF and {\em WiggleZ} data. In particular, we investigate five different models for the growth index Îł\gamma, by comparing their cosmological evolution using observational data of the growth rate of structure formation at different redshifts. Performing a joint likelihood analysis of the recent supernovae type Ia data, the Cosmic Microwave Background shift parameter, Baryonic Acoustic Oscillations and the growth rate data, we determine the free parameters of the Îł(z)\gamma(z) parametrizations and we statistically quantify their ability to represent the observations. We find that the addition of the 6dF and {\em WiggleZ} growth data in the likelihood analysis improves significantly the statistical results. As an example, considering a constant growth index we find Ωm0=0.273±0.011\Omega_{m0}=0.273\pm 0.011 and Îł=0.586−0.074+0.079\gamma=0.586^{+0.079}_{-0.074}.Comment: 8 pages, 5 figures, Accepted for publication by International J. of Modern Physics D (IJMPD). arXiv admin note: substantial text overlap with arXiv:1203.672

    Phenolic-rich extracts from avocado fruit residues as functional food ingredients with antioxidant and antiproliferative properties

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    In this study, the total phenolic compounds content and profile, the nutritional value, the antioxidant and antiproliferative activities of avocado peel, seed coat, and seed extracts were characterized. Additionally, an in-silico analysis was performed to identify the phenolic compounds with the highest intestinal absorption and Caco-2 permeability. The avocado peel extract possessed the highest content of phenolic compounds (309.95 ± 25.33 mMol GA/100 g of extract) and the lowest effective concentration (EC50) against DPPH and ABTS radicals (72.64 ± 10.70 and 181.68 ± 18.47, respectively). On the other hand, the peel and seed coat extracts had the lowest energy densities (226.06 ± 0.06 kcal/100g and 219.62 ± 0.49 kcal/100g, respectively). Regarding the antiproliferative activity, the avocado peel extract (180 ± 40 ”g/mL) showed the lowest inhibitory concentration (IC50), followed by the seed (200 ± 21 ”g/mL) and seed coat (340 ± 32 ”g/mL) extracts. The IC50 of the extracts induced apoptosis in Caco-2 cells at the early and late stages. According to the in-silico analysis, these results could be related to the higher Caco-2 permeability to hy-droxysalidroside, salidroside, sakuranetin, and luteolin. Therefore, this study provides new insights regarding the potential use of these extracts as functional ingredients with antioxidant and antiproliferative properties and as medicinal agents in diseases related to oxidative stress such as cancer. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Is there an association between sleep disorders and diabetic foot? A scoping review

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    Diabetic foot is associated with a low quality of life since physical disabilities, mood disturbances and psychological disorders are frequent. One of the most important biological processes to ensure quality of life is sleep. Sleep disorders can impair glycemic control in patients with diabetes mellitus or even cause long-term type 2 diabetes mellitus. The aim of this study is to carry out a scoping review about the association between sleep cycle disorders and diabetic foot. PubMed, Scopus, CINAHL, PEDro, Cochrane Library, SCIELO and EMBASE databases were chosen for the search and the following terms were used: “diabetic foot”,“sleep*”,“rest-activity”,“mood” and“behavior”. All the studies should include outcome variables about sleep and diabetic foot. Finally, 12 articles were selected, all of whichwere observational. The most frequent variables were those regarding diabetic foot ulcer aspects and diabetic neuropathy on one side, and obstructive sleep apnea, sleep duration and sleep quality on the other side. The results suggest that there is a possible association between obstructive sleep apnea and the presence or history of diabetic foot ulcers. No direct associations between sleep quality or sleep duration and diabetic foot or diabetic foot ulcer variables have been found

    Ovine enzootic ataxia. It's histopathological evolution

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    Se describen las lesiones histo patológicas correspondientes a casos de ovinos con procesos de ataxia, consistentes en cromatolisis de las neuronas y procesos avanzados de desmielinización. Las zonas del SNC mås afectadas correspondieron a la zona lumbar, cervical y toråcica de la médula espinal y a la corteza cerebelosa. Los anålisis efectuados de dosajes de cobre no coinciden con los valores inferiores descritos por otros autores para esta enfermedad.Histopathologic lesions of ovines with ataxia are described. They const of neurone chromatolysis and advanced processes of desmylinization. The cerebellar cortex, the cervical, thoracic and lumbar medulla were de most affected zones of the Central Nervous System. The cooper dosages of the liver made by polarography differed with the minimum levels reported by other research workers for this disease.Facultad de Ciencias Veterinaria

    A parametrization of the growth index of matter perturbations in various Dark Energy models and observational prospects using a Euclid-like survey

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    We provide exact solutions to the cosmological matter perturbation equation in a homogeneous FLRW universe with a vacuum energy that can be parametrized by a constant equation of state parameter ww and a very accurate approximation for the Ansatz w(a)=w0+wa(1−a)w(a)=w_0+w_a(1-a). We compute the growth index \gamma=\log f(a)/\log\Om_m(a), and its redshift dependence, using the exact and approximate solutions in terms of Legendre polynomials and show that it can be parametrized as γ(a)=γ0+γa(1−a)\gamma(a)=\gamma_0+\gamma_a(1-a) in most cases. We then compare four different types of dark energy (DE) models: wΛw\LambdaCDM, DGP, f(R)f(R) and a LTB-large-void model, which have very different behaviors at z\gsim1. This allows us to study the possibility to differentiate between different DE alternatives using wide and deep surveys like Euclid, which will measure both photometric and spectroscopic redshifts for several hundreds of millions of galaxies up to redshift z≃2z\simeq 2. We do a Fisher matrix analysis for the prospects of differentiating among the different DE models in terms of the growth index, taken as a given function of redshift or with a principal component analysis, with a value for each redshift bin for a Euclid-like survey. We use as observables the complete and marginalized power spectrum of galaxies P(k)P(k) and the Weak Lensing (WL) power spectrum. We find that, using P(k)P(k), one can reach (2%, 5%) errors in (w0,wa)(w_0, w_a), and (4%, 12%) errors in (γ0,γa)(\gamma_0, \gamma_a), while using WL we get errors at least twice as large. These estimates allow us to differentiate easily between DGP, f(R)f(R) models and Λ\LambdaCDM, while it would be more difficult to distinguish the latter from a variable equation of state parameter or LTB models using only the growth index.}Comment: 29 pages, 7 figures, 6 table

    A web application to optimization of transport in military operations

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    Transport is an operation necessary to carry out any logistical mission, especially in times of war, peace or natural disasters. The distribution of the necessary demanded resources is done from a military unit, to the different locations or military bases. However, operational efficiency depends on the planners. In more than 60% of trips, shipping and return isn’t efficient, even between the same units. The cause is the non-consolidation of trips and the lack of return load, coming from perimeter units. Planning is done without consolidating trips and in many cases on demand. It’s presented a web application, a parametric framework to any geographical area, given the integration with applications such as Google Maps¼. Computational times are reasonable, given a to hardiness to the problem. The software architecture is scalable and extensible, complying with software quality practices present in ISO 25000
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