Some comments on "The Mathematical Universe"

I discuss some problems related to extreme mathematical realism, focusing on a recently proposed "shut-up-and-calculate" approach to physics (arXiv:0704.0646, arXiv:0709.4024). I offer arguments for a moderate alternative, the essence of which lies in the acceptance that mathematics is (at least in part) a human construction, and discuss concrete consequences of this--at first sight purely philosophical--difference in point of view.Comment: 11 page

Biocompatible hybrids based on nanographene oxide covalently linked to glycolporphyrins: synthesis, characterization and biological evaluation

The major limitation in the development of hybrids based on graphene oxide (GO) and porphyrins is their dispersibility and stability in aqueous systems due to the hydrophobic character induced by porphyrins. Most of the previous approaches reported the direct functionalization of GO with polyethylene glycol (PEG) chains followed by the self-assembly of porphyrins by π-π interactions. Here, new hybrids were prepared using porphyrins previously functionalized with different number/types of glycol branches to be covalently attached through esterification to the carboxyl groups of GO sheets of nanometric dimensions. The number of the glycol chains and its relative position in the porphyrin core showed to be fundamental to improve the hybrids dispersion and stability in aqueous solutions. The best performing hybrids were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared, UV-Vis absorption and fluorescence spectroscopy. The in vitro biocompatibility assessment of these hybrids was conducted using human Saos-2 cells. Their effects on cell proliferation and viability, the generation of reactive oxygen species as well as the cell morphology after cell uptake were analysed. The results demonstrate the biocompatibility of these hybrid nanomaterials with human Saos-2 cells, which is very promising for future application in biomedicine namely in cancer therapy.publishe

Performance of Glass Resistive Plate Chambers for a high granularity semi-digital calorimeter

A new design of highly granular hadronic calorimeter using Glass Resistive Plate Chambers (GRPCs) with embedded electronics has been proposed for the future International Linear Collider (ILC) experiments. It features a 2-bit threshold semi-digital read-out. Several GRPC prototypes with their electronics have been successfully built and tested in pion beams. The design of these detectors is presented along with the test results on efficiency, pad multiplicity, stability and reproducibility.Comment: 16 pages, 15 figure

Accuracy and Stability of Computing High-Order Derivatives of Analytic Functions by Cauchy Integrals

High-order derivatives of analytic functions are expressible as Cauchy integrals over circular contours, which can very effectively be approximated, e.g., by trapezoidal sums. Whereas analytically each radius r up to the radius of convergence is equal, numerical stability strongly depends on r. We give a comprehensive study of this effect; in particular we show that there is a unique radius that minimizes the loss of accuracy caused by round-off errors. For large classes of functions, though not for all, this radius actually gives about full accuracy; a remarkable fact that we explain by the theory of Hardy spaces, by the Wiman-Valiron and Levin-Pfluger theory of entire functions, and by the saddle-point method of asymptotic analysis. Many examples and non-trivial applications are discussed in detail.Comment: Version 4 has some references and a discussion of other quadrature rules added; 57 pages, 7 figures, 6 tables; to appear in Found. Comput. Mat

Characterization of rhizobium tropici CIAT899 nodulation factors: the role of nodH and nodPQ genes in their sulfation

We have purified and characterized the nodulation factors produced by Rhizobium tropici CIAT899. This strain produces a large variety of nodulation factors, these being a mixture of sulfated or nonsulfated penta- or tetra-chitooligosaccharides to which any of six different fatty acyl moieties may be attached to nitrogen of the nanreducing terminal residue, In this mixture we have also found methylated or nonmethylated lipo-chitin oligosaccharides. Here we describe a novel lipo-chitin-oligosaccharide consisting of a linear backbone of 4 N-acetylglucosamine residues and one mannose that is the reducing-terminal residue and bearing a C18:1 fatty acyl moiety on the nonreducing terminal residue. In addition, we have identified, cloned, and sequenced R. tropici nodH and nodPQ genes, generated mutations in the nodH and nodQ genes, and tested the mutant strains far nodulation in Phaseolus and Leucaena plants, Our results indicate that the sulfate group present in wildtype Nod factors plays a major role in nodulation of Leucaena plants by strain CIAT899 of R. tropici.Microbial Biotechnolog

The Project PTDC/CTE-GIX/098968/2008 - High resolution stratigraphy of the Lower Jurassic organic-rich marine series in the Lusitanian Basin (Portugal): Initial expectations and results

Apresenta-se neste trabalho uma caracterização e os principais resultados do Projecto “Estratigrafia de alta resolução das séries marinhas ricas em matéria orgânica do Jurássico Inferior da Bacia Lusitânica”, financiado pela Fundação para a Ciência e Tecnologia (Portugal). Este projecto centrou-se numa análise estratigráfica multidisciplinar baseada num vasto conjunto de parâmetros bióticos e abióticos da sucessão margo-calcária rica em matéria orgânica do Jurássico Inferior da bacia, envolvendo sete objetivos principais: 1. Análise sedimentológica (mineralógica, textural e composicional) e sequencial da sucessão hemipelágica do Jurássico Inferior (Sinemuriano superior–Toarciano); 2. Precisões biostratigráficas a partir do registo de amonóides do intervalo compreendido entre o Sinemuriano superior e o Pliensbaquiano superior; 3. Análise paleontológica e paleoecológica da macrofauna bentónica (fundamentalmente braquiópodes e bivalves); 4. Análise biostratigráfica, taxonómica e paleoecológica da fauna de ostracodos (Sinemuriano–Toarciano); 5. Análise quimiostratigráfica baseada principalmente nos isótopos estáveis de carbono (Sinemuriano–Pliensbaquiano); 6. Análise geoquímica e de petrografia orgânica (carbono orgânico total, pirólise Rock-Eval e biomarcadores) do Sinemuriano–Pliensbaquiano; 7. Análise dos padrões de variação dos raios gama (Sinemuriano–Toarciano.This work presents the main results of the Project ”High resolution stratigraphy of the Lower Jurassic organic-rich marine series in the Lusitanian Basin (Portugal)”, supported by the Portuguese Foundation for Science and Technology. This project was focused on a multidisciplinary stratigraphic analysis based on the study of a range of biotic and abiotic parameters of the Lower Jurassic marl–limestone succession rich in organic matter, embracing seven main objectives: 1. Sedimentological (mineralogical, textural and compositional) and sequential analysis of the whole Lower Jurassic hemipelagic succession (Upper Sinemurian–Toarcian); 2. Ammonite biostratigraphic precisions of the Upper Sinemurian and Upper Pliensbachian; 3. Palaeontological and palaeoecological analysis of the benthic macrofauna (especially brachiopods and bivalves); 4. Biostratigraphical, taxonomic and palaeoecological analysis of the ostracod fauna (Sinemurian–Toarcian); 5. Chemostratigraphic analysis based mainly on carbon stable isotopes (Sinemurian–Pliensbachian); 6. Organic geochemical and petrographic analysis (total organic carbon, palynofacies, Rock-Eval pyrolysis and biomarkers) of the Sinemurian–Pliensbachian; 7. Vertical variation patterns of gamma-ray analysis (Sinemurian–Toarcian). Besides the new results in each specific scientific domain (for example, biostratigraphy, palaeoecology, sedimentology, sequence stratigraphy and cyclicity, chemostratigraphy and organic geochemistry), the integration of all data, in several cases at highresolution level, allows emphasizing the achievement of two main transverse goals: the improvement of the stratigraphy and sedimentary knowledge of the Lower Jurassic series of western Iberia margin, with implications in the palaoenvironmental and palaeoceanographic interpretations of the Tethyan pre-Atlantic basins dynamics and global correlation; taking into consideration the huge number of organic geochemical parameters analyzed, the results of this research contributed significantly to understand the role of the different Sinemurian and Pliensbachian organic-rich intervals as potential hydrocarbon generation sources (quality of organic matter and maturation).Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEFondo Europeo de Desarrollo Regional (COMPETE- FEDER)Fundação para a Ciência e a Tecnologia (FCT)pu

Early life risk factors and their cumulative effects as predictors of overweight in Spanish children

Objectives: To explore early life risk factors of overweight/obesity at age 6 years and their cumulative effects on overweight/obesity at ages 2, 4 and 6 years. Methods: Altogether 1031 Spanish children were evaluated at birth and during a 6-year follow-up. Early life risk factors included: parental overweight/obesity, parental origin/ethnicity, maternal smoking during pregnancy, gestational weight gain, gestational age, birth weight, caesarean section, breastfeeding practices and rapid infant weight gain collected via hospital records. Cumulative effects were assessed by adding up those early risk factors that significantly increased the risk of overweight/obesity. We conducted binary logistic regression models. Results: Rapid infant weight gain (OR 2.29, 99% CI 1.54–3.42), maternal overweight/obesity (OR 1.93, 99% CI 1.27–2.92), paternal overweight/obesity (OR 2.17, 99% CI 1.44–3.28), Latin American/Roma origin (OR 3.20, 99% CI 1.60–6.39) and smoking during pregnancy (OR 1.61, 99% CI 1.01–2.59) remained significant after adjusting for confounders. A higher number of early life risk factors accumulated was associated with overweight/obesity at age 6 years but not at age 2 and 4 years. Conclusions: Rapid infant weight gain, parental overweight/obesity, maternal smoking and origin/ethnicity predict childhood overweight/obesity and present cumulative effects. Monitoring children with rapid weight gain and supporting a healthy parental weight are important for childhood obesity prevention

The Dynamics of Brane-World Cosmological Models

Brane-world cosmology is motivated by recent developments in string/M-theory and offers a new perspective on the hierarchy problem. In the brane-world scenario, our Universe is a four-dimensional subspace or {\em brane} embedded in a higher-dimensional {\em bulk} spacetime. Ordinary matter fields are confined to the brane while the gravitational field can also propagate in the bulk, leading to modifications of Einstein's theory of general relativity at high energies. In particular, the Randall-Sundrum-type models are self-consistent and simple and allow for an investigation of the essential non-linear gravitational dynamics. The governing field equations induced on the brane differ from the general relativistic equations in that there are nonlocal effects from the free gravitational field in the bulk, transmitted via the projection of the bulk Weyl tensor, and the local quadratic energy-momentum corrections, which are significant in the high-energy regime close to the initial singularity. In this review we discuss the asymptotic dynamical evolution of spatially homogeneous brane-world cosmological models containing both a perfect fluid and a scalar field close to the initial singularity. Using dynamical systems techniques it is found that, for models with a physically relevant equation of state, an isotropic singularity is a past-attractor in all orthogonal spatially homogeneous models (including Bianchi type IX models). In addition, we describe the dynamics in a class of inhomogeneous brane-world models, and show that these models also have an isotropic initial singularity. These results provide support for the conjecture that typically the initial cosmological singularity is isotropic in brane-world cosmology.Comment: Einstein Centennial Review Article: to appear in CJ

The evolution of language: a comparative review

For many years the evolution of language has been seen as a disreputable topic, mired in fanciful "just so stories" about language origins. However, in the last decade a new synthesis of modern linguistics, cognitive neuroscience and neo-Darwinian evolutionary theory has begun to make important contributions to our understanding of the biology and evolution of language. I review some of this recent progress, focusing on the value of the comparative method, which uses data from animal species to draw inferences about language evolution. Discussing speech first, I show how data concerning a wide variety of species, from monkeys to birds, can increase our understanding of the anatomical and neural mechanisms underlying human spoken language, and how bird and whale song provide insights into the ultimate evolutionary function of language. I discuss the ‘‘descended larynx’ ’ of humans, a peculiar adaptation for speech that has received much attention in the past, which despite earlier claims is not uniquely human. Then I will turn to the neural mechanisms underlying spoken language, pointing out the difficulties animals apparently experience in perceiving hierarchical structure in sounds, and stressing the importance of vocal imitation in the evolution of a spoken language. Turning to ultimate function, I suggest that communication among kin (especially between parents and offspring) played a crucial but neglected role in driving language evolution. Finally, I briefly discuss phylogeny, discussing hypotheses that offer plausible routes to human language from a non-linguistic chimp-like ancestor. I conclude that comparative data from living animals will be key to developing a richer, more interdisciplinary understanding of our most distinctively human trait: language