Reaction-diffusion fronts under stochastic advection

We study front propagation in stirred media using a simplified modelization of the turbulent flow. Computer simulations reveal the existence of the two limiting propagation modes observed in recent experiments with liquid phase isothermal reactions. These two modes respectively correspond to a wrinkled although sharp propagating interface and to a broadened one. Specific laws relative to the enhancement of the front velocity in each regime are confirmed by our simulations.

Genome-wide association and longitudinal analyses reveal genetic loci linking pubertal height growth, pubertal timing and childhood adiposity.

The pubertal height growth spurt is a distinctive feature of childhood growth reflecting both the central onset of puberty and local growth factors. Although little is known about the underlying genetics, growth variability during puberty correlates with adult risks for hormone-dependent cancer and adverse cardiometabolic health. The only gene so far associated with pubertal height growth, LIN28B, pleiotropically influences childhood growth, puberty and cancer progression, pointing to shared underlying mechanisms. To discover genetic loci influencing pubertal height and growth and to place them in context of overall growth and maturation, we performed genome-wide association meta-analyses in 18 737 European samples utilizing longitudinally collected height measurements. We found significant associations (P < 1.67 × 10(-8)) at 10 loci, including LIN28B. Five loci associated with pubertal timing, all impacting multiple aspects of growth. In particular, a novel variant correlated with expression of MAPK3, and associated both with increased prepubertal growth and earlier menarche. Another variant near ADCY3-POMC associated with increased body mass index, reduced pubertal growth and earlier puberty. Whereas epidemiological correlations suggest that early puberty marks a pathway from rapid prepubertal growth to reduced final height and adult obesity, our study shows that individual loci associating with pubertal growth have variable longitudinal growth patterns that may differ from epidemiological observations. Overall, this study uncovers part of the complex genetic architecture linking pubertal height growth, the timing of puberty and childhood obesity and provides new information to pinpoint processes linking these traits.

Langevin approach to generate synthetic turbulent flows

We present an analytical scheme, easily implemented numerically, to generate synthetic Gaussian turbulent flows by using a linear Langevin equation, where the noise term acts as a stochastic stirring force. The characteristic parameters of the velocity field are well introduced, in particular the kinematic viscosity and the spectrum of energy. As an application, the diffusion of a passive scalar is studied for two different energy spectra. Numerical results are compared favorably with analytical calculations.

Front dynamics in turbulent media

A study of a stable front propagating in a turbulent medium is presented. The front is generated through a reaction-diffusion equation, and the turbulent medium is statistically modeled using a Langevin equation. Numerical simulations indicate the presence of two different dynamical regimes. These regimes appear when the turbulent flow either wrinkles a still rather sharp propagating interfase or broadens it. Specific dependences of the propagating velocities on stirring intensities appropriate to each case are found and fitted when possible according to theoretically predicted laws. Different turbulent spectra are considered.

Invariant decomposition of the retarded electromagnetic field.

The integral representation of the electromagnetic two-form, defined on Minkowski space-time, is studied from a new point of view. The aim of the paper is to obtain an invariant criteria in order to define the radiative field. This criteria generalizes the well-known structureless charge case. We begin with the curvature two-form, because its field equations incorporate the motion of the sources. The gauge theory methods (connection one-forms) are not suited because their field equations do not incorporate the motion of the sources. We obtain an integral solution of the Maxwell equations in the case of a flow of charges in irrotational motion. This solution induces us to propose a new method of solving the problem of the nature of the retarded radiative field. This method is based on a projection tensor operator which, being local, is suited to being implemented on general relativity. We propose the field equations for the pair {electromagnetic field, projection tensor J. These field equations are an algebraic differential first-order system of oneforms, which verifies automatically the integrability conditions.

Biological, clinical and population relevance of 95 loci for blood lipids.

Plasma concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides are among the most important risk factors for coronary artery disease (CAD) and are targets for therapeutic intervention. We screened the genome for common variants associated with plasma lipids in >100,000 individuals of European ancestry. Here we report 95 significantly associated loci (P < 5 x 10(-8)), with 59 showing genome-wide significant association with lipid traits for the first time. The newly reported associations include single nucleotide polymorphisms (SNPs) near known lipid regulators (for example, CYP7A1, NPC1L1 and SCARB1) as well as in scores of loci not previously implicated in lipoprotein metabolism. The 95 loci contribute not only to normal variation in lipid traits but also to extreme lipid phenotypes and have an impact on lipid traits in three non-European populations (East Asians, South Asians and African Americans). Our results identify several novel loci associated with plasma lipids that are also associated with CAD. Finally, we validated three of the novel genes-GALNT2, PPP1R3B and TTC39B-with experiments in mouse models. Taken together, our findings provide the foundation to develop a broader biological understanding of lipoprotein metabolism and to identify new therapeutic opportunities for the prevention of CAD.

Common variants in mendelian kidney disease genes and their association with renal function.

Many common genetic variants identified by genome-wide association studies for complex traits map to genes previously linked to rare inherited Mendelian disorders. A systematic analysis of common single-nucleotide polymorphisms (SNPs) in genes responsible for Mendelian diseases with kidney phenotypes has not been performed. We thus developed a comprehensive database of genes for Mendelian kidney conditions and evaluated the association between common genetic variants within these genes and kidney function in the general population. Using the Online Mendelian Inheritance in Man database, we identified 731 unique disease entries related to specific renal search terms and confirmed a kidney phenotype in 218 of these entries, corresponding to mutations in 258 genes. We interrogated common SNPs (minor allele frequency >5%) within these genes for association with the estimated GFR in 74,354 European-ancestry participants from the CKDGen Consortium. However, the top four candidate SNPs (rs6433115 at LRP2, rs1050700 at TSC1, rs249942 at PALB2, and rs9827843 at ROBO2) did not achieve significance in a stage 2 meta-analysis performed in 56,246 additional independent individuals, indicating that these common SNPs are not associated with estimated GFR. The effect of less common or rare variants in these genes on kidney function in the general population and disease-specific cohorts requires further research.

Systematic assessment of items influencing Crohn's disease patient's preferences in selecting an anti-TNF agent (Choose TNF trial)

Background and Aims: The three anti-TNF agents infliximab (IFX), adalimumab (ADA) andcertolizumab pegol (CZP) have demonstrated similar efficacy in induction and maintenanceof response and remission in Crohn's disease (CD) treatment. Given the comparability ofthese drugs, patient's preferences may influence the choice of the product. However, dataon patient's preferences for choosing anti-TNF agents are lacking. We therefore aimed toassess the CD patient's appraisal to select the drug of his choice and to identify factorsguiding this decision.Methods: A prospective survey among anti-TNF-naive CD patientswas performed. Patients were provided a description of the three anti-TNF agents focusingon indication, application mode (s.c. vs. i.v.), application time intervals, setting of application(hospital vs. private practice vs. patient's home), average time to apply the medication permonth, typical side effects, and the scientific evidence of efficacy and safety available for everydrug. Patients answered a questionnaire consisting of 17 questions, covering demographic,disease-specific, and medication data.Results: Hundred patients (47f/53m, mean age 45±16years) completed the questionnaire. Disease duration was <1year in 7%, 1-5 years in 31%,and >5 years in 62% of patients. Disease location was ileal in 33%, colonic in 40%, andileocolonic in 27%. Disease phenotype was inflammatory in 68%, stenosing in 29%, andinternally fistulizing in 3% of patients. Additionally, 20% had perianal fistulizing disease.Patients were already treated with the following drugs: mesalamines 61%, budesonide 44%,prednisone 97%, thiopurines 78%, methotrexate 16%. In total, 30% had already heardabout IFX, 20% about ADA, and 11% about CZP. Thirty-six percent voted for treatmentwith ADA, 28% for CZP, and 25% for IFX, whereas 11% were undecided. The followingfactors influenced the patient's decision for choosing a specific anti-TNF drug (severalanswers possible): side effects 76%, physician's recommendation 66%, application mode54%, efficacy experience 52%, time to spend for therapy 27%, patient's recommendations21%, interactions with other medications 12%. The single most important factor for choosinga specific anti-TNF was (1 answer): side effect profile 35%, physician's recommendation22%, efficacy experience 21%, application mode 13%, patient's recommendations 5%, timespent for therapy 3%, interaction with other medications 1%.Conclusions: The majority ofpatients preferred anti-TNF syringes to infusions. The safety profile of the drugs and thephysician's recommendation are major factors influencing the patient's choice for a specificanti-TNF drug. Patient's issues about safety and lifestyle habits should be taken into accountwhen prescribing specific anti-TNF formulations.

La utilización del concepto de ADN en nuestra sociedad: tecnociencia, frases hechas y errores científicos

La tecnología científica relacionada con el ADN y sus aplicaciones ha revolucionado nuestra sociedad. La información respecto a estos progresos se ha extendido rápidamente mediante los medios de comunicación. A su vez, las personas han incorporado conceptos de las tecnologías relacionadas con el ADN en su cosmovisión. La utilización de frases hechas basadas en el ADN ha tenido un gran éxito mediático, pero algunas de ellas contienen errores científicos graves. En este artículo se pretende mostrar dichos errores y posibles vías de actuación para corregirlos. Palabras clave: ADN, cosmovisión, frases hechas, selección natural, darwinismo, herencia de caracteres adquiridos, lamarckismo.

Evolución: de la especie humana al cyborg

Resumen: Gracias a la evolución biológica y cultural el ser humano ha sido capaz de adaptarse al ambiente. Una opción para mejorar las prestaciones humanas podría ser la obtención de un cyborg o ser humano biónico en el cual la parte inorgánica fuese un chip computacional conectado directamente al cerebro. Esta y otras posibilidades se debaten en el presente artículo. Palabras clave: Evolución biológica, selección natural, evolución cultural, cyborg, biónico, inteligencia.

Reflexiones sobre los cyborgs y los robots: evolucion humana y aumentacion

The human being has changed in time due to both, biological and cultural evolution. In a first step, biological evolution was the cornerstone of the changes in our species. However, cultural evolution was also a key element producing adaptations that allowed the evolution of modern human being. These adaptations include aspects as different as clothing, tools, reading and writing, calculation and some forms of rudimentary prosthesis. Technoscience has enhanced these adaptations that conduce to the concept of broad-sense cyborg. Present human society includes a huge proportion of these latter individuals. In this article we discuss this reality and the future of our society based on the interconnections between humans, cyborgs and robots.

Precisiones interdisciplinares y conceptuales de los términos cyborg, clon humnao y robot

La palabra cyborg (del cyborg: cyber, cibernético y organism, organismo), designa una criatura compuesta de elementos orgánicos y mecánicos que mejoran las capacidades biológicas a través de la tecnología: es un individuo en parte hombre y en parte máquina.

El Memorial de Barcelona a Archer Milton Huntington, el fundador de la Hispanic Society of America, y a su esposa, la escultora, Anna Hyatt Huntington.

Barcelona en 1954 se anticipo a todos los homenajes, dedicando a Archer Milton Huntington (New York, 1870- Bathel, Connecticut, 1955) un monumento en reconocimiento a su excepcional figura como coleccionista e hispanófilo y también a su esposa, Anna Vaughn Hyatt Huntington (Cambridge, 1876 - California, 1973), excelente escultora que generosamente secundo los propósitos filo hispanos de su consorte. De esta manera Barcelona quería dejar constancia de su devoción y tributo a este reconocido coleccionista y filántropo americano que ayudo a vencer el llamado "Paradigma Prescott", historiador que había defendido las tesis sobre la leyenda negra española. A la vez que se reconocía que Archer M. Huntington ocupaba un lugar preeminente en la línea del hispanismo americano conjuntamente con los nombres de George Ticknor (1791 -1871), Washington Irving (1783-1859) y Henry Longfellow (1807-1882).