Evolution of a structured cell population endowed with plasticity of traits under constraints on and between the traits.

Confronted with the biological problem of managing plasticity in cell populations, which is in particular responsible for transient and reversible drug resistance in cancer, we propose a rationale consisting of an integro-differential and a reaction-advection-diffusion equation, the properties of which are studied theoretically and numerically. By using a constructive finite volume method, we show the existence and uniqueness of a weak solution and illustrate by numerical approximations and their simulations the capacity of the model to exhibit divergence of traits. This feature may be theoretically interpreted as describing a physiological step towards multicellularity in animal evolution and, closer to present-day clinical challenges in oncology, as a possible representation of bet hedging in cancer cell populations.

Hydrodynamic limits for kinetic flocking models of Cucker-Smale type.

We analyse the asymptotic behavior for kinetic models describing the collective behavior of animal populations. We focus on models for self-propelled individuals, whose velocity relaxes toward the mean orientation of the neighbors. The self-propelling and friction forces together with the alignment and the noise are interpreted as a collision/interaction mechanism acting with equal strength.

Adhesion and volume constraints via nonlocal interactions determine cell organisation and migration profiles.

The description of the cell spatial pattern and characteristic distances is fundamental in a wide range of physio-pathological biological phenomena, from morphogenesis to cancer growth. Discrete particle models are widely used in this field, since they are focused on the cell-level of abstraction and are able to preserve the identity of single individuals reproducing their behavior. In particular, a fundamental role in determining the usefulness and the realism of a particle mathematical approach is played by the choice of the intercellular pairwise interaction kernel and by the estimate of its parameters.

On global minimizers of repulsive-attractive power-law interaction energies.

We consider the minimization of the repulsive-attractive power-law interaction energies that occur in many biological and physical situations. We show the existence of global minimizers in the discrete setting and obtain bounds for their supports independently of the number of Dirac deltas in a certain range of exponents. These global discrete minimizers correspond to the stable spatial profiles of flock patterns in swarming models.

Complexity reduction of rate-equations models for two-choice decision-making.

We are concerned with the complexity reduction of a stochastic system of differential equations governing the dynamics of a neuronal circuit describing a decision-making task. This reduction is based on the slow-fast behavior of the problem and holds on the whole phase space and not only locally around the spontaneous state. Macroscopic quantities, such as performance and reaction times, computed applying this reduction are in agreement with previous works in which the complexity reduction is locally performed at the spontaneous point by means of a Taylor expansion.

[Fetal ovarian cyst: prenatal diagnosis, perinatal outcome and treatment. Case series and literature review].

Background: Ovarian cysts in fetal abdominal tumors are more frequently diagnosed during pregnancy. Most of the time are usually small, asymptomatic and resolve spontaneously during pregnancy or in early neonatal life.

Objective: To describe the clinical and ultrasound cases with prenatal diagnosis of ovarian cyst treated in our center between 2002 and 2005.

Low intrathecal immune response of anti-EBNA-1 antibodies and EBV DNA from multiple sclerosis patients.

Numerous studies have been carried out to determine whether an Epstein-Barr virus (EBV) infection can be considered a risk factor for multiple sclerosis (MS), following the evidence of an increase in IgG response to nuclear antigen-1 (EBNA-1) in both serum and cerebrospinal fluid (CSF) from MS patients. However, the possible interaction between EBV and MS has still not been well characterized, and the possible pathogenic role is yet to be determined. A case-control study (76 cases and 75 controls) was conducted to investigate anti-EBV antibodies synthesis in serum and CSF through intrathecal specific IgG synthesis to EBNA-1, as well as the presence of EBV DNA in plasma, peripheral blood mononuclear cells, and CSF from MS patients.

A decision-making Fokker-Planck model in computational neuroscience.

In computational neuroscience, decision-making may be explained analyzing models based on the evolution of the average firing rates of two interacting neuron populations, e.g., in bistable visual perception problems.

Development and preliminary evaluation of a rapid oligochromatographic assay for specific detection of new human influenza A H1N1 virus.

A new oligochromatographic assay, Speed-Oligo Novel Influenza A H1N1, was designed and optimized for the specific detection of the 2009 influenza A H1N1 virus. The assay is based on a PCR method coupled to detection of PCR products by means of a dipstick device. The target sequence is a 103-bp fragment within the hemagglutinin gene.

Adaptive dynamics via Hamilton-Jacobi approach and entropy methods for a juvenile-adult model.

We consider a nonlinear system describing a juvenile-adult population undergoing small mutations. We analyze two aspects: from a mathematical point of view, we use an entropy method to prove that the population neither goes extinct nor blows-up; from an adaptive evolution point of view, we consider small mutations on a long time scale and study how a monomorphic or a dimorphic initial population evolves towards an Evolutionarily Stable State. Our method relies on an asymptotic analysis based on a constrained Hamilton-Jacobi equation.

Detection of a mariner-like element and a miniature inverted-repeat transposable element (MITE) associated with the heterochromatin from ants of the genus Messor and their possible involvement for satellite DNA evolution.

The satellite DNA of ants Messor bouvieri, M. barbarus and M. structor, studied in a previous paper, is organized as tandemly repeated 79-bp monomers in the three species showing high sequence similarity.

Evolutionary dynamics of satellite DNA in species of the Genus Formica (Hymenoptera, Formicidae).

The satellite DNA has been characterized in eight species of the Formica genus. This satellite DNA is organized as tandemly repeated 129-bp monomers in all species and it presents internal inverted repeats. The results of all the analyses performed in the sequences sampled from Formica cunicularia, F.