Cooperation transitions in social games induced by aspiration-driven players

Cooperation and defection are social traits whose evolutionary origin is still unresolved. Recent behavioral experiments with humans suggested that strategy changes are driven mainly by the individuals' expectations and not by imitation. This work theoretically analyzes and numerically explores an aspiration-driven strategy updating in a well-mixed population playing games. The payoffs of the game matrix and the aspiration are condensed into just two parameters that allow a comprehensive description of the dynamics. We find continuous and abrupt transitions in the cooperation density with excellent agreement between theory and the Gillespie simulations. Under strong selection, the system can display several levels of steady cooperation or get trapped into absorbing states. These states are still relevant for experiments even when irrational choices are made due to their prolonged relaxation times. Finally, we show that for the particular case of the Prisoner Dilemma, where defection is the dominant strategy under imitation mechanisms, the self-evaluation update instead favors cooperation nonlinearly with the level of aspiration. Thus, our work provides insights into the distinct role between imitation and self-evaluation with no learning dynamics.Comment: 11 pages, 9 figures; Correction of typos in the metadat

Effects of a gluten-free diet on gut microbiota and immune function in healthy adult human subjects

7 pages, 1 figure, 3 tables.Diet influences the composition of the gut microbiota and host's health, particularly in patients suffering from food-related diseases. Coeliac disease (CD) is a permanent intolerance to cereal gluten proteins and the only therapy for the patients is to adhere to a life-long gluten-free diet (GFD). In the present preliminary study, the effects of a GFD on the composition and immune function of the gut microbiota were analysed in ten healthy subjects (mean age 30·3 years) over 1 month. Faecal microbiota was analysed by fluorescence in situ hybridisation (FISH) and quantitative PCR (qPCR). The ability of faecal bacteria to stimulate cytokine production by peripheral blood mononuclear cells (PBMC) was determined by ELISA. No significant differences in dietary intake were found before and after the GFD except for reductions (P = 0·001) in polysaccharides. Bifidobacterium, Clostridium lituseburense and Faecalibacterium prausnitzii proportions decreased (P = 0·007, P = 0·031 and P = 0·009, respectively) as a result of the GFD analysed by FISH. Bifidobacterium, Lactobacillus and Bifidobacterium longum counts decreased (P = 0·020, P = 0·001 and P = 0·017, respectively), while Enterobacteriaceae and Escherichia coli counts increased (P = 0·005 and P = 0·003) after the GFD assessed by qPCR. TNF-α, interferon-γ, IL-10 and IL-8 production by PBMC stimulated with faecal samples was also reduced (P = 0·021, P = 0·037, P = 0·002 and P = 0·007, respectively) after the diet. Therefore, the GFD led to reductions in beneficial gut bacteria populations and the ability of faecal samples to stimulate the host's immunity. Thus, the GFD may constitute an environmental variable to be considered in treated CD patients for its possible effects on gut health.This work was supported by grants AGL2008-01440/ALI and Consolider Fun-C-Food 20 CSD2007-00063 from the Spanish Ministry of Science and Innovation.Peer reviewe

Systematic review of stereotactic body radiotherapy in stage III non-small cell lung cancer

Despite adequate treatment, 50% of stage III locally advanced inoperable non-small cell lung cancer (NSCLC) patients have a locoregional relapse. Local control on early stages on the contrary, is as high as 85-90% with stereotactic body radiotherapy (SBRT). The addition of SBRT to conventional chemoradiation or its use in monotherapy in stage III NSCLC is a novel strategy to decrease local failure that has been explored by various authors. This is a systematic review of studies using SBRT in inoperable stage III NSCLC. Search results obtained 141 articles of which only 6 original studies were pointed as relevant. Three of these studies were prospective, of which 2 were phase I dose-scalation studies and remaining 3 were retrospective. In summary, SBRT outcomes on 134 patients were included. Median dose in the SBRT treatment was 22.5 Gy in 2 to 7 fractions. Obtained global toxicity was 3.7% grade 5 and 14.17% grade 3. Dose-escalation studies proposed a 2 fraction SBRT schedule of 20-24 Gy, obtaining a 78% local control rate at 1 year and an OS of 67%. Initial improvement in local control with this innovative therapeutic strategy has led to ongoing phase II and III clinical trials that will evaluate the efficiency of SBRT in stage III NSCLC clinical scenario

Microorganismos para mejorar el estado de salud de individuos con trastornos relacionados con la ingesta de gluten

La presente invención aporta microorganismos para el tratamientode alergias alimentarias, más concretamente la enfermedad celiaca, así como métodos para su sección. Sus mecanismos de acción incluyen: (i) la regulación de la respuesta inmunológica innata y adaptativa; (ii) la reducción de la concentración de epítopos tóxicos en la luz intestinal; (iii) el fortalecimiento de la función barrera defensiva frente a bacterias y antígenos perjudiciales, y (iv) el aporte de actividades enzimáticas que favorecen la digestión.Peer reviewedConsejo Superior de Investigaciones Científicas (España)T3 Traducción de patente europe

Intestinal dysbiosis and reduced immunoglobulin-coated bacteria associated with coeliac disease in children

<p>Abstract</p> <p>Background</p> <p>Coeliac disease is a chronic intestinal inflammatory disorder due to an aberrant immune response to dietary gluten proteins in genetically predisposed individuals. Mucosal immune response through IgA secretion constitutes a first line of defence responsible for neutralizing noxious antigens and pathogens. The aim of this study was the characterization of the relationships between immunoglobulin-coated bacteria and bacterial composition of faeces of coeliac disease (CD) patients, untreated and treated with a gluten-free diet (GFD) and healthy controls.</p> <p>Results</p> <p>IgA-coated faecal bacterial levels were significantly lower in both untreated and treated CD patients than in healthy controls. IgG and IgM-coated bacterial levels were also significantly lower in treated CD patients than in untreated CD patients and controls. Gram-positive to Gram-negative bacteria ratio was significantly reduced in both CD patients compared to controls. <it>Bifidobacterium</it>, <it>Clostridium histolyticum</it>, <it>C. lituseburense </it>and <it>Faecalibacterium prausnitzii </it>group proportions were less abundant (<it>P </it>< 0.050) in untreated CD patients than in healthy controls. <it>Bacteroides-Prevotella </it>group proportions were more abundant (<it>P </it>< 0.050) in untreated CD patients than in controls. Levels of IgA coating the <it>Bacteroides-Prevotella </it>group were significantly reduced (<it>P </it>< 0.050) in both CD patients in comparison with healthy controls.</p> <p>Conclusions</p> <p>In CD patients, reduced IgA-coated bacteria is associated with intestinal dysbiosis, which altogether provide new insights into the possible relationships between the gut microbiota and the host defences in this disorder.</p

Synchronization waves in geometric networks

We report synchronization of networked excitable nodes embedded in a metric space, where the connectivity properties are mostly determined by the distance between units. Such a high clustered structure, combined with the lack of long-range connections, prevents full synchronization and yields instead the emergence of synchronization waves. We show that this regime is optimal for information transmission through the system, as it enhances the options of reconstructing the topology from the dynamics. Measurements of topological and functional centralities reveal that the wave-synchronization state allows detection of the most structurally relevant nodes from a single observation of the dynamics, without any a priori information on the model equations ruling the evolution of the ensembl

Enteroviruses in Spain: virological and epidemiological studies over 10 years (1988-97)

A total of 15,662 clinical samples were analysed for enterovirus (EV) isolation in cell cultures during a 10-year period (1988-97). Furthermore, 210 isolates of EV obtained in primary laboratories within Spain from patients with meningitis were characterized. The total number of EV typed was 758, including 727 non-polio EV and 31 Sabin-like (SL) polioviruses. Twenty-eight EV serotypes were represented. Echoviruses comprised 90% (653/727) of fully typed non-polio EV. The four most prevalent serotypes were echovirus 30, echovirus 9, echovirus 6 and echovirus 4. Echovirus 30 was the main serotype associated with meningitis. Echovirus 9 was the aetiological agent in 20 outbreaks of meningitis while the occurrence of echovirus 6 was localized in 1 year (1997). Coxsackieviruses A and B occurred in 3 and 7% of the non-polio EV respectively. Coxsackievirus B5 presented the relative greater abundance. This paper examines the epidemiology of EV in Spain to serotype level over a 10-year period with special attention to non-polio EV associated with meningitis.Dr I. Casas is a postdoctoral fellow supported by the Institute de Salud Carlos III, Becas de Perfeccionamiento (97/4165). We acknowledge the assistance provided by clinical colleagues in other virology laboratories: Gurutze Rubio (Cruces, Bilbao, Hospital), Nuria Rabella (Santa Cruz y San Pablo, Barcelona Hospital), Joaquin Otero (Doce de Octubre, Madrid Hospital). We also thank Raquel Noguerol, Hortensia del Pozo and Isidoro Bustillo for their technical assistance and an anonymous referee for many useful suggestions. This work was partially supported by Fondo de Investigación Sanitaria grant FIS 96/0304.S

Integration versus segregation in functional brain networks

We propose a new methodology to evaluate the balance between segregation and integration in functional brain networks by using singular value decomposition techniques. By means of magnetoencephalography, we obtain the brain activity of a control group of 19 individuals during a memory task. Next, we project the node-to-node correlations into a complex network that is analyzed from the perspective of its modular structure encoded in the contribution matrix. In this way, we are able to study the role that nodes play I/O its community and to identify connector and local hubs. At the mesoscale level, the analysis of the contribution matrix allows us to measure the degree of overlapping between communities and quantify how far the functional networks are from the configuration that better balances the integrated and segregated activit

Emergence of Small-World Anatomical Networks in Self-Organizing Clustered Neuronal Cultures

In vitro primary cultures of dissociated invertebrate neurons from locust ganglia are used to experimentally investigate the morphological evolution of assemblies of living neurons, as they self-organize from collections of separated cells into elaborated, clustered, networks. At all the different stages of the culture's development, identification of neurons' and neurites' location by means of a dedicated software allows to ultimately extract an adjacency matrix from each image of the culture. In turn, a systematic statistical analysis of a group of topological observables grants us the possibility of quantifying and tracking the progression of the main network's characteristics during the self-organization process of the culture. Our results point to the existence of a particular state corresponding to a small-world network configuration, in which several relevant graph's micro- and meso-scale properties emerge. Finally, we identify the main physical processes ruling the culture's morphological transformations, and embed them into a simplified growth model qualitatively reproducing the overall set of experimental observations