2,691 research outputs found

    Scaling properties of the Penna model

    Full text link
    We investigate the scaling properties of the Penna model, which has become a popular tool for the study of population dynamics and evolutionary problems in recent years. We find that the model generates a normalised age distribution for which a simple scaling rule is proposed, that is able to reproduce qualitative features for all genome sizes.Comment: 4 pages, 4 figure

    Sharp gene pool transition in a population affected by phenotype-based selective hunting

    Full text link
    We use a microscopic model of population dynamics, a modified version of the well known Penna model, to study some aspects of microevolution. This research is motivated by recent reports on the effect of selective hunting on the gene pool of bighorn sheep living in the Ram Mountain region, in Canada. Our model finds a sharp transition in the structure of the gene pool as some threshold for the number of animals hunted is reached.Comment: 5 pages, 4 figure

    Insulinização em pacientes portadores de DM2

    Get PDF
    Essa segunda opinão formativa (SOF) sobre insulinização nos paciente portadores de Diabetes Mellitus tipo 2 tem por objetivo responder às dúvidas mais frequentes dos médicos das equipes de saúde da família (ESF) que atuam na atenção primária de saúde (APS) no que se refere ao processo de instituição dessa terapia nos pacientes diabéticos. A partir de um levantamento das dúvidas mais frequentes presentes nas teleconsultorias enviadas para um especialista em endocrinologia, construiu-se esse material abordando, no DM2, os objetivos e metas terapêuticas, causas do insucesso terapêutico e quando/como/porque insulinizar. Espera-se com essa segunda opinião formativa uma capacitação e atualização dos médicos da APS no processo de insulinização do DM2, otimizando, assim, o tratamento do paciente diabético e, por consequência, minimizando as complicações advindas do mau controle desses.1.0Centro de Tecnologia em Saúde(CETES) -UFMG; Núcleo de Telessaúde da Faculdade de Medicina da UFMG

    Dynamical Instability in a Trimeric Chain of Interacting Bose-Einstein Condensates

    Get PDF
    We analyze thoroughly the mean-field dynamics of a linear chain of three coupled Bose-Einstein condensates, where both the tunneling and the central-well relative depth are adjustable parameters. Owing to its nonintegrability, entailing a complex dynamics with chaos occurrence, this system is a paradigm for longer arrays whose simplicity still allows a thorough analytical study.We identify the set of dynamics fixed points, along with the associated proper modes, and establish their stability character depending on the significant parameters. As an example of the remarkable operational value of our analysis, we point out some macroscopic effects that seem viable to experiments.Comment: 5 pages, 3 figure

    A Bayesian estimate of the CMB-large-scale structure cross-correlation

    Full text link
    Evidences for late-time acceleration of the Universe are provided by multiple probes, such as Type Ia supernovae, the cosmic microwave background (CMB) and large-scale structure (LSS). In this work, we focus on the integrated Sachs--Wolfe (ISW) effect, i.e., secondary CMB fluctuations generated by evolving gravitational potentials due to the transition between, e.g., the matter and dark energy (DE) dominated phases. Therefore, assuming a flat universe, DE properties can be inferred from ISW detections. We present a Bayesian approach to compute the CMB--LSS cross-correlation signal. The method is based on the estimate of the likelihood for measuring a combined set consisting of a CMB temperature and a galaxy contrast maps, provided that we have some information on the statistical properties of the fluctuations affecting these maps. The likelihood is estimated by a sampling algorithm, therefore avoiding the computationally demanding techniques of direct evaluation in either pixel or harmonic space. As local tracers of the matter distribution at large scales, we used the Two Micron All Sky Survey (2MASS) galaxy catalog and, for the CMB temperature fluctuations, the ninth-year data release of the Wilkinson Microwave Anisotropy Probe (WMAP9). The results show a dominance of cosmic variance over the weak recovered signal, due mainly to the shallowness of the catalog used, with systematics associated with the sampling algorithm playing a secondary role as sources of uncertainty. When combined with other complementary probes, the method presented in this paper is expected to be a useful tool to late-time acceleration studies in cosmology.Comment: 21 pages, 15 figures, 4 tables. We extended the previous analyses including WMAP9 Q, V and W channels, besides the ILC map. Updated to match accepted ApJ versio

    Update on the ICUD-SIU consultation on multi-parametric magnetic resonance imaging in localised prostate cancer

    Get PDF
    Introduction: Prostate cancer (PCa) imaging is a rapidly evolving field. Dramatic improvements in prostate MRI during the last decade will probably change the accuracy of diagnosis. This chapter reviews recent current evidence about MRI diagnostic performance and impact on PCa management. Materials and methods: The International Consultation on Urological Diseases nominated a committee to review the literature on prostate MRI. A search of the PubMed database was conducted to identify articles focussed on MP-MRI detection and staging protocols, reporting and scoring systems, the role of MP-MRI in diagnosing PCa prior to biopsy, in active surveillance, in focal therapy and in detecting local recurrence after treatment. Results: Differences in opinion were reported in the use of the strength of magnets [1.5 Tesla (T) vs. 3T] and coils. More agreement was found regarding the choice of pulse sequences; diffusion-weighted MRI (DW-MRI), dynamic contrast-enhanced MRI (DCE MRI), and/or MR spectroscopy imaging (MRSI) are recommended in addition to conventional T2-weighted anatomical sequences. In 2015, the Prostate Imaging Reporting and Data System (PI-RADS version 2) was described to standardize image acquisition and interpretation. MP-MRI improves detection of clinically significant PCa (csPCa) in the repeat biopsy setting or before the confirmatory biopsy in patients considering active surveillance. It is useful to guide focal treatment and to detect local recurrences after treatment. Its role in biopsy-naive patients or during the course of active surveillance remains debated. Conclusion: MP-MRI is increasingly used to improve detection of csPCa and for the selection of a suitable therapeutic approach

    Recurrent high-biomass blooms of Alexandrium taylorii (Dinophyceae), a HAB species expanding in the Mediterranean.

    Get PDF
    none9openGIACOBBE M.G., PENNA A., GANGEMI E., MASO' M; GARCES E., FRAGA S., BRAVO I., AZZARO F., PENNA N.Giacobbe, M. G.; Penna, Antonella; Gangemi, E.; Maso', M; Garces, E.; Fraga, S.; Bravo, I.; Azzaro, F.; Penna, N

    Cosmological constant constraints from observation-derived energy condition bounds and their application to bimetric massive gravity

    Full text link
    Among the various possibilities to probe the theory behind the recent accelerated expansion of the universe, the energy conditions (ECs) are of particular interest, since it is possible to confront and constrain the many models, including different theories of gravity, with observational data. In this context, we use the ECs to probe any alternative theory whose extra term acts as a cosmological constant. For this purpose, we apply a model-independent approach to reconstruct the recent expansion of the universe. Using Type Ia supernova, baryon acoustic oscillations and cosmic-chronometer data, we perform a Markov Chain Monte Carlo analysis to put constraints on the effective cosmological constant Ωeff0\Omega^0_{\rm eff}. By imposing that the cosmological constant is the only component that possibly violates the ECs, we derive lower and upper bounds for its value. For instance, we obtain that 0.59<Ωeff0<0.910.59 < \Omega^0_{\rm eff} < 0.91 and 0.40<Ωeff0<0.930.40 < \Omega^0_{\rm eff} < 0.93 within, respectively, 1σ1\sigma and 3σ3\sigma confidence levels. In addition, about 30\% of the posterior distribution is incompatible with a cosmological constant, showing that this method can potentially rule it out as a mechanism for the accelerated expansion. We also study the consequence of these constraints for two particular formulations of the bimetric massive gravity. Namely, we consider the Visser's theory and the Hassan and Roses's massive gravity by choosing a background metric such that both theories mimic General Relativity with a cosmological constant. Using the Ωeff0\Omega^0_{\rm eff} observational bounds along with the upper bounds on the graviton mass we obtain constraints on the parameter spaces of both theories.Comment: 11 pages, 4 figures, 1 tabl
    • …
    corecore