Next Generation Cosmology: Constraints from the Euclid Galaxy Cluster Survey

We study the characteristics of the galaxy cluster samples expected from the European Space Agency's Euclid satellite and forecast constraints on cosmological parameters describing a variety of cosmological models. The method used in this paper, based on the Fisher Matrix approach, is the same one used to provide the constraints presented in the Euclid Red Book (Laureijs et al.2011). We describe the analytical approach to compute the selection function of the photometric and spectroscopic cluster surveys. Based on the photometric selection function, we forecast the constraints on a number of cosmological parameter sets corresponding to different extensions of the standard LambdaCDM model. The dynamical evolution of dark energy will be constrained to Delta w_0=0.03 and Delta w_a=0.2 with free curvature Omega_k, resulting in a (w_0,w_a) Figure of Merit (FoM) of 291. Including the Planck CMB covariance matrix improves the constraints to Delta w_0=0.02, Delta w_a=0.07 and a FoM=802. The amplitude of primordial non-Gaussianity, parametrised by f_NL, will be constrained to \Delta f_NL ~ 6.6 for the local shape scenario, from Euclid clusters alone. Using only Euclid clusters, the growth factor parameter \gamma, which signals deviations from GR, will be constrained to Delta \gamma=0.02, and the neutrino density parameter to Delta Omega_\nu=0.0013 (or Delta \sum m_\nu=0.01). We emphasise that knowledge of the observable--mass scaling relation will be crucial to constrain cosmological parameters from a cluster catalogue. The Euclid mission will have a clear advantage in this respect, thanks to its imaging and spectroscopic capabilities that will enable internal mass calibration from weak lensing and the dynamics of cluster galaxies. This information will be further complemented by wide-area multi-wavelength external cluster surveys that will already be available when Euclid flies. [Abridged]Comment: submitted to MNRA

Sparse random matrices: the eigenvalue spectrum revisited

We revisit the derivation of the density of states of sparse random matrices. We derive a recursion relation that allows one to compute the spectrum of the matrix of incidence for finite trees that determines completely the low concentration limit. Using the iterative scheme introduced by Biroli and Monasson [J. Phys. A 32, L255 (1999)] we find an approximate expression for the density of states expected to hold exactly in the opposite limit of large but finite concentration. The combination of the two methods yields a very simple simple geometric interpretation of the tails of the spectrum. We test the analytic results with numerical simulations and we suggest an indirect numerical method to explore the tails of the spectrum.Comment: 18 pages, 7 figures. Accepted version, minor corrections, references adde

Brazilian embryo industry in context: pitfalls, lessons, and expectations for the future.

Proceedings of the 31st Annual Meeting of the Brazilian Embryo Technology Society (SBTE); Cabo de Santo Agostinho, PE, Brazil, August 17th to 19th, 2017. Abstract

Hysteretic Optimization For Spin Glasses

The recently proposed Hysteretic Optimization (HO) procedure is applied to the 1D Ising spin chain with long range interactions. To study its effectiveness, the quality of ground state energies found as a function of the distance dependence exponent, $\sigma$, is assessed. It is found that the transition from an infinite-range to a long-range interaction at $\sigma=0.5$ is accompanied by a sharp decrease in the performance . The transition is signaled by a change in the scaling behavior of the average avalanche size observed during the hysteresis process. This indicates that HO requires the system to be infinite-range, with a high degree of interconnectivity between variables leading to large avalanches, in order to function properly. An analysis of the way auto-correlations evolve during the optimization procedure confirm that the search of phase space is less efficient, with the system becoming effectively stuck in suboptimal configurations much earlier. These observations explain the poor performance that HO obtained for the Edwards-Anderson spin glass on finite-dimensional lattices, and suggest that its usefulness might be limited in many combinatorial optimization problems.Comment: 6 pages, 9 figures. To appear in JSTAT. Author website: http://www.bgoncalves.co

Produção de biogás a partir do glicerol oriundo do biodiesel.

bitstream/item/55346/1/COT11018.pd

National culture and earnings management in developed and emerging countries

Purpose This study investigates how the association between national culture and earnings management compares between developed and emerging countries. Design/methodology/approach The empirical analysis relies on a sample of 6,313 firm-year observations from 11 emerging markets and 27,605 firm-year observations from 22 developed countries. The authors use ordinary least squares regression methods to test the hypotheses of the study. Findings Based on Hofstede's (2011) cultural dimensions, the authors find that firms from countries with a higher level of uncertainty avoidance and individualism are less likely to engage in earnings management, but the effect of uncertainty avoidance (individualism) is more (less) pronounced in the emerging countries. Moreover, the authors demonstrate that firms from emerging (developed) countries with higher levels of power distance and masculinity are less (more) likely to engage in earnings management. Finally, the authors find evidence of a trade-off between accruals-based and real earnings management in firms from countries with greater long-term orientation and an indulgence cultural dimension. Originality/value This paper adds to the literature by theoretically discussing and empirically analysing the role that developed and emerging countries' development plays on the effect of national culture on earnings management.info:eu-repo/semantics/acceptedVersio

Statistical properties of genealogical trees

We analyse the statistical properties of genealogical trees in a neutral model of a closed population with sexual reproduction and non-overlapping generations. By reconstructing the genealogy of an individual from the population evolution, we measure the distribution of ancestors appearing more than once in a given tree. After a transient time, the probability of repetition follows, up to a rescaling, a stationary distribution which we calculate both numerically and analytically. This distribution exhibits a universal shape with a non-trivial power law which can be understood by an exact, though simple, renormalization calculation. Some real data on human genealogy illustrate the problem, which is relevant to the study of the real degree of diversity in closed interbreeding communities.Comment: Accepted for publication in Phys. Rev. Let

Teores de amilose e amilopectina em genótipos de mandioca (Manihot esculenta Crantz).

A mandioca (Manihot esculenta Crantz) é uma das principais fontes alimentícias para populações de países tropicais e importante matéria-prima para a extração de amido (VALLE et al., 2004). O Brasil é o maior produtor das Américas (RAMOS JÚNIOR et al., 2009). Em 2011, a produção nacional foi em cerca de 25 milhões de toneladas raízes (IBGE, 2013). O amido, polissacarídeo de reserva das plantas, constitui-se na principal fonte de energia alimentar, fornecendo de 70 a 80% das calorias na alimentação humana. De acordo com a origem botânica desse polissacarídeo, são empregados os termos técnicos amido e fécula. Quando proveniente das partes superiores das plantas, como os grãos, é denominado amido, e fécula se for proveniente de partes subterrâneas, como raízes ou tubérculos (LEONEL; CEREDA, 2002). É formado essencialmente por dois tipos de polímeros de glicose: a amilose e a amilopectina (COUTINHO, 2007; LACERDA, 2006). A amilose é uma molécula essencialmente linear, composta por unidades de D-glucose ligadas em alfa (1-4) com pequeno número de ramificações. A amilopectina é altamente ramificada e composta por unidades de D-glucose ligadas em alfa (1-4) e com 5 a 6% de ligações alfa (1-6) nos pontos de ramificação (SILVA et al., 2008). Os teores de amilose e amilopectina variam nas cultivares de mandioca. Diante disso, o presente estudo teve por objetivo avaliar as concentrações de amilose e amilopectina em diferentes genótipos de mandioca

Replicated Transfer Matrix Analysis of Ising Spin Models on `Small World' Lattices

We calculate equilibrium solutions for Ising spin models on `small world' lattices, which are constructed by super-imposing random and sparse Poissonian graphs with finite average connectivity c onto a one-dimensional ring. The nearest neighbour bonds along the ring are ferromagnetic, whereas those corresponding to the Poisonnian graph are allowed to be random. Our models thus generally contain quenched connectivity and bond disorder. Within the replica formalism, calculating the disorder-averaged free energy requires the diagonalization of replicated transfer matrices. In addition to developing the general replica symmetric theory, we derive phase diagrams and calculate effective field distributions for two specific cases: that of uniform sparse long-range bonds (i.e. `small world' magnets), and that of (+J/-J) random sparse long-range bonds (i.e. `small world' spin-glasses).Comment: 22 pages, LaTeX, IOP macros, eps figure