The role of three-nucleon potentials within the shell model: past and present

We survey the impact of nuclear three-body forces on structure properties of nuclei within the shell model. It has long been acknowledged, since the seminal works of Zuker and coworkers, that three-body forces play a fundamental role in making the monopole component of shell-model Hamiltonians, derived from realistic nucleon-nucleon potentials, able to reproduce the observed evolution of the shell structure. In the vast majority of calculations, however, their effects have been taken into account by shell-model practitioners by introducing ad hoc modifications of the monopole matrix elements. During last twenty years, a new theoretical approach, framed within the chiral perturbation theory, has progressed in developing nuclear potentials, where two- and many-body components are naturally and consistently built in. This new class of nuclear forces allows to carry out nuclear structure studies that are improving our ability to understand nuclear phenomena in a microscopic approach. We provide in this work an update on the status of the nuclear shell model based on realistic Hamiltonians that are derived from two- and three-nucleon chiral potentials, focusing on the role of the three-body component to provide the observed shell evolution and closure properties, as well as the location of driplines. To this end, we present the results of shell-model calculations and their comparison with recent experimental measurements, which enlighten the relevance of the inclusion of three-nucleon forces to master our knowledge of the physics of atomic nuclei.Comment: Accepted for publication in Progress in Particle and Nuclear Physic

Desarrollo de un proyecto de ciencia basado en el uso de diversas inteligencias

Solve and create problems are characteristic of an intelligent and creative mind. From a practical sense, intelligence procedures and leads to correct results but creativity allow us to innovate on procedures, interpretation of results and generated products. This project combines science and art, aiming to promote intelligence and creativity in students in the second grade of primary school. The work is part of the study of general aspects of the biology of insects in various learning environments. The results indicate a process of understanding the basic structures of insects, the biological sense of communication sounds and movements of the basic elements of music making, of how an orchestra is organized and a dance and especially the resolution of problems related to science and art.Resolver y plantear problemas son características de una mente inteligente y creativa. Desde un sentido práctico, la inteligencia nos lleva a procedimientos y resultados correctos pero la creatividad nos permite innovar sobre los procedimientos, la interpretación de los resultados y los productos generados.Este proyecto, que combinó la ciencia y el arte, tuvo la intención de promover estas dos características de la mente e iniciar, en estudiantes en estudiantes del segundo grado de primaria, el estudio de los aspectos generales de la biología de los insectos a través de generar ambientes diversos de aprendizaje. El proyecto dio como resultado un proceso de comprensión de las estructuras básicas de los insectos, del sentido biológico de la comunicación por sonidos y de sus movimientos, de los elementos básicos de la creación musical, de la forma como se organiza una orquesta y una danza y, sobre todo, de la resolución de problemas relacionados con la ciencia y el arte.Palabras clave: inteligencia; creatividad; ciencia; arte; aprendizaje cooperativo; contextos educativos.Development of a science project based on the use of several intelligencesSolve and create problems are characteristic of an intelligent and creative mind. From a practical sense, intelligence procedures and leads to correct results but creativity allow us to innovate on procedures, interpretation of results and generated products. This project combines science and art, aiming to promote intelligence and creativity in students in the second grade of primary school. The work is part of the study of general aspects of the biology of insects in various learning environments. The results indicate a process of understanding the basic structures of insects, the biological sense of communication sounds and movements of the basic elements of music making, of how an orchestra is organized and a dance and especially the resolution of problems related to science and art.Keywords: intelligence; creativity; science; art; cooperative learning; educational contexts

Hypoxanthine-guanine phosophoribosyltransferase (HPRT) deficiency: Lesch-Nyhan syndrome

Deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity is an inborn error of purine metabolism associated with uric acid overproduction and a continuum spectrum of neurological manifestations depending on the degree of the enzymatic deficiency. The prevalence is estimated at 1/380,000 live births in Canada, and 1/235,000 live births in Spain. Uric acid overproduction is present inall HPRT-deficient patients and is associated with lithiasis and gout. Neurological manifestations include severe action dystonia, choreoathetosis, ballismus, cognitive and attention deficit, and self-injurious behaviour. The most severe forms are known as Lesch-Nyhan syndrome (patients are normal at birth and diagnosis can be accomplished when psychomotor delay becomes apparent). Partial HPRT-deficient patients present these symptoms with a different intensity, and in the least severe forms symptoms may be unapparent. Megaloblastic anaemia is also associated with the disease. Inheritance of HPRT deficiency is X-linked recessive, thus males are generally affected and heterozygous female are carriers (usually asymptomatic). Human HPRT is encoded by a single structural gene on the long arm of the X chromosome at Xq26. To date, more than 300 disease-associated mutations in the HPRT1 gene have been identified. The diagnosis is based on clinical and biochemical findings (hyperuricemia and hyperuricosuria associated with psychomotor delay), and enzymatic (HPRT activity determination in haemolysate, intact erythrocytes or fibroblasts) and molecular tests. Molecular diagnosis allows faster and more accurate carrier and prenatal diagnosis. Prenatal diagnosis can be performed with amniotic cells obtained by amniocentesis at about 15–18 weeks' gestation, or chorionic villus cells obtained at about 10–12 weeks' gestation. Uric acid overproduction can be managed by allopurinol treatment. Doses must be carefully adjusted to avoid xanthine lithiasis. The lack of precise understanding of the neurological dysfunction has precluded development of useful therapies. Spasticity, when present, and dystonia can be managed with benzodiazepines and gamma-aminobutyric acid inhibitors such as baclofen. Physical rehabilitation, including management of dysarthria and dysphagia, special devices to enable hand control, appropriate walking aids, and a programme of posture management to prevent deformities are recommended. Self-injurious behaviour must be managed by a combination of physical restraints, behavioural and pharmaceutical treatments

Th Inducing POZ-Kruppel Factor (ThPOK) Is a Key Regulator of the Immune Response since the Early Steps of Colorectal Carcinogenesis

We purposed to evaluate the role of Th inducing POZ-Kruppel Factor (ThPOK), a transcriptional regulator of T cell fate, in tumour-induced immune system plasticity in colorectal carcinogenesis. The amounts of CD4+, CD8+ and CD56+ and ThPOK+ cells infiltrate in normal colorectal mucosa (NM), in dysplastic aberrant crypt foci (microadenomas, MA), the earliest detectable lesions in colorectal carcinogenesis, and in colorectal carcinomas (CRC), were measured, and the colocalization of ThPOK with the above-mentioned markers of immune cells was evaluated using confocal microscopy. Interestingly, ThPOK showed a prominent increase since MA. A strong colocalization of ThPOK with CD4 both in NM and in MA was observed, weaker in carcinomas. Surprisingly, there was a peak in the colocalization levels of ThPOK with CD8 in MA, which was evident, although to a lesser extent, in carcinomas, too. In conclusion, according to the data of the present study, ThPOK may be considered a central regulator of the earliest events in the immune system during colorectal cancer development, decreasing the immune response against cancer cells

Lack of an Antibacterial Response Defect in Drosophila Toll-9 Mutant

Toll and Toll-like receptors represent families of receptors involved in mediating innate immunity response in insects and mammals. Although Drosophila proteome contains multiple Toll paralogs, Toll-1 is, so far, the only receptor to which an immune role has been attributed. In contrast, every single mammalian TLR is a key membrane receptor upstream of the vertebrate immune signaling cascades. The prevailing view is that TLR-mediated immunity is ancient. Structural analysis reveals that Drosophila Toll-9 is the most closely related to vertebrate TLRs and utilizes similar signaling components as Toll-1. This suggests that Toll-9 could be an ancestor of TLR-like receptors and could have immune function. Consistently, it has been reported that over-expression of Toll-9 in immune tissues is sufficient to induce the expression of some antimicrobial peptides in flies. These results have led to the idea that Toll-9 could be a constitutively active receptor that maintain significant levels of antimicrobial molecules and therefore provide constant basal protection against micro-organisms. To test theses hypotheses, we generated and analyzed phenotypes associated with a complete loss-of-function allele of Toll-9. Our results suggest that Toll-9 is neither required to maintain a basal anti-microbial response nor to mount an efficient immune response to bacterial infection

Morphological variability of native maize (Zea mays L.) of the west highland of Puebla and east highland of Tlaxcala, Mexico

The objective of this research was to assess the morphological variability of maize landraces native of the west highland of Puebla and east highland of Tlaxcala, México, in order to, besides define it, related it to races, commercial varieties and with the altitude of the localities of seed collection. The genetic resources evaluated were 134 accessions collected in 34 localities, along with 10 controls. Experiments were established on three localities using a Lattice 12 x 12. Thirty-two morphological traits were analyzed, 27 of them resulting with highly significant differences, reflecting the high variability at the level of morphological characters, many of them of agronomic interest. From variance analysis 16 traits were selected for use in a cluster analysis through the Modified Localization Method, which joint the populations in six groups, most of them in the group 1, with morphological traits of long cycle varieties: high plants, with greater primary branches of the tassel, greater ear diameter and length, and greater grain length and width. The conclusions indicate that the morphological variability of Landraces is not associated with the altitude of localities of seed collection and that these have more relation with Chalqueño race, small with Conico race, absent with Conico Norteño and Palomero Toluqueño races and almost absent with commercial varieties.The objective of this research was to assess the morphological variability of maize landraces native of the west highland of Puebla and east highland of Tlaxcala, México, in order to, besides define it, related it to races, commercial varieties and with the altitude of the localities of seed collection. The genetic resources evaluated were 134 accessions collected in 34 localities, along with 10 controls. Experiments were established on three localities using a Lattice 12 x 12. Thirty-two morphological traits were analyzed, 27 of them resulting with highly significant differences, reflecting the high variability at the level of morphological characters, many of them of agronomic interest. From variance analysis 16 traits were selected for use in a cluster analysis through the Modified Localization Method, which joint the populations in six groups, most of them in the group 1, with morphological traits of long cycle varieties: high plants, with greater primary branches of the tassel, greater ear diameter and length, and greater grain length and width. The conclusions indicate that the morphological variability of Landraces is not associated with the altitude of localities of seed collection and that these have more relation with Chalqueño race, small with Conico race, absent with Conico Norteño and Palomero Toluqueño races and almost absent with commercial varieties

Translation without eIF2 Promoted by Poliovirus 2A Protease

Poliovirus RNA utilizes eIF2 for the initiation of translation in cell free systems. Remarkably, we now describe that poliovirus translation takes place at late times of infection when eIF2 is inactivated by phosphorylation. By contrast, translation directed by poliovirus RNA is blocked when eIF2 is inactivated at earlier times. Thus, poliovirus RNA translation exhibits a dual mechanism for the initiation of protein synthesis as regards to the requirement for eIF2. Analysis of individual poliovirus non-structural proteins indicates that the presence of 2Apro alone is sufficient to provide eIF2 independence for IRES-driven translation. This effect is not observed with a 2Apro variant unable to cleave eIF4G. The level of 2Apro synthesized in culture cells is crucial for obtaining eIF2 independence. Expression of the N-or C-terminus fragments of eIF4G did not stimulate IRES-driven translation, nor provide eIF2 independence, consistent with the idea that the presence of 2Apro at high concentrations is necessary. The finding that 2Apro provides eIF2-independent translation opens a new and unsuspected area of research in the field of picornavirus protein synthesis

Planck 2013 results. XXII. Constraints on inflation

We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the scalar spectral index to be ns = 0:9603 _ 0:0073, ruling out exact scale invariance at over 5_: Planck establishes an upper bound on the tensor-to-scalar ratio of r < 0:11 (95% CL). The Planck data thus shrink the space of allowed standard inflationary models, preferring potentials with V00 < 0. Exponential potential models, the simplest hybrid inflationary models, and monomial potential models of degree n _ 2 do not provide a good fit to the data. Planck does not find statistically significant running of the scalar spectral index, obtaining dns=dln k = 0:0134 _ 0:0090. We verify these conclusions through a numerical analysis, which makes no slowroll approximation, and carry out a Bayesian parameter estimation and model-selection analysis for a number of inflationary models including monomial, natural, and hilltop potentials. For each model, we present the Planck constraints on the parameters of the potential and explore several possibilities for the post-inflationary entropy generation epoch, thus obtaining nontrivial data-driven constraints. We also present a direct reconstruction of the observable range of the inflaton potential. Unless a quartic term is allowed in the potential, we find results consistent with second-order slow-roll predictions. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit by __2 e_ _ 10; however, Bayesian evidence does not prefer these models. We constrain several single-field inflation models with generalized Lagrangians by combining power spectrum data with Planck bounds on fNL. Planck constrains with unprecedented accuracy the amplitude and possible correlation (with the adiabatic mode) of non-decaying isocurvature fluctuations. The fractional primordial contributions of cold dark matter (CDM) isocurvature modes of the types expected in the curvaton and axion scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelated isocurvature component can improve the _2 e_ by approximately 4 as a result of slightly lowering the theoretical prediction for the ` <_ 40 multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions