Building initial models of rotating white dwarfs with SPH

A general procedure to build self-gravitational, rotating equilibrium structures with the Smoothed Particle Hydrodynamics (SPH) technique does not exist. In particular, obtaining stable rotating configurations for white dwarf (WD) stars is currently a major drawback of many astrophysical simulations. Rotating WDs with low internal temperatures are connected with both, explosive and implosive scenarios such as type Ia supernova explosions or neutron stars formation. Simulations of these events with SPH codes demand stable enough particle configurations as initial models. In this work we have developed and tested a relaxation method to obtain equilibrium configurations of rotating WDs. This method is straightforward and takes advantage of the excellent mass and angular momentum conservation properties of the SPH technique. Although we focus on rigid rotation and its potential applications to several Type Ia supernova scenarios, we also show that our proposal is also able to provide good initial models in differential rotation, which has the potential to benefit many other types of simulations where rotation plays a capital role, like disk evolution and stellar formation.Peer ReviewedPostprint (published version

Diseño de un sistema de información para la gestión basado en las actividades: El caso de D.A.P 310.

En el presente trabajo, exponemos el proceso de diseño e implantación de un sistema de información para la gestión en la empresa D.A.P. El sistema elegido sigue la filosofía de los modelos de gestión y costes basados en las actividades ABM / ABC. Comenzamos describiendo las características de los sistemas de gestión y costes basados en las actividades frente a los sistemas de gestión tradicionales, haciendo destacar sus ventajas para justificar así su conveniencia en este tipo de empresas. A continuación describimos las características de la actividad desarrollada por la empresa y del entorno de la misma para, finalmente, exponer el proceso seguido para la implantación del sistema de gestión y costes.In this paper we explain the design and implementation process of a management information system on D.A.P. organization. The selected system is based on activity-based management and activity-based costing models (ABM / ABC). In this work, we start comparing the ABM / ABC characteristics with traditional systems, emphasizing their advantages in order to justify the suitability in these organizations. Also, the activity developed by the firm and the surrounding characteristics are described. Finally, we explain the process used for the management and costing system implementation

Silencing of Smed-βcatenin1 generates radial-like hypercephalized planarians

7 páginas, 4 figuras. Supplementary material for this article is available at http://dev.biologists.org/cgi/content/full/135/7/1215/DC1Little is known about the molecular mechanisms responsible for axis establishment during non-embryonic processes such as regeneration and homeostasis. To address this issue, we set out to analyze the role of the canonical Wnt pathway in planarians, flatworms renowned for their extraordinary morphological plasticity. Canonical Wnt signalling is an evolutionarily conserved mechanism to confer polarity during embryonic development, specifying the anteroposterior (AP) axis in most bilaterians and the dorsoventral (DV) axis in early vertebrate embryos. β-Catenin is a key element in this pathway, although it is a bifunctional protein that is also involved in cell-cell adhesion. Here, we report the characterization of two β-catenin homologs from Schmidtea mediterranea (Smed-βcatenin1/2). Loss of function of Smed-βcatenin1, but not Smed-βcatenin2, in both regenerating and intact planarians, generates radial-like hypercephalized planarians in which the AP axis disappears but the DV axis remains unaffected, representing a unique example of a striking body symmetry transformation. The radial-like hypercephalized phenotype demonstrates the requirement for Smed-βcatenin1 in AP axis re-establishment and maintenance, and supports a conserved role for canonical Wnt signalling in AP axis specification, whereas the role of β-catenin in DV axis establishment would be a vertebrate innovation. When considered alongside the protein domains present in each S. mediterranea β-catenin and the results of functional assays in Xenopus embryos demonstrating nuclear accumulation and axis induction with Smed-βcatenin1, but not Smed-βcatenin2, these data suggest that S. mediterraneaβ -catenins could be functionally specialized and that only Smed-βcatenin1 is involved in Wnt signalling.This work was supported by grants from the Ministerio de Educación y Ciencia, Spain, from AGAUR (Generalitat de Catalunya, Spain), and from La Junta de Andalucía, Spain.Peer reviewe

Cuckoo Search with Lévy Flights for Weighted Bayesian Energy Functional Optimization in Global-Support Curve Data Fitting

ABSTRACT. The problem of data fitting is very important in many theoretical and applied fields. In this paper, we consider the problem of optimizing a weighted Bayesian energy functional for data fitting by using global-support approximating curves. By global-support curves we mean curves expressed as a linear combination of basis functions whose support is the whole domain of the problem, as opposed to other common approaches in CAD/CAM and computer graphics driven by piecewise functions (such as B-splines and NURBS) that provide local control of the shape of the curve. Our method applies a powerful nature-inspired metaheuristic algorithm called cuckoo search, introduced recently to solve optimization problems. A major advantage of this method is its simplicity: cuckoo search requires only two parameters, many fewer than other metaheuristic approaches, so the parameter tuning becomes a very simple task.The paper shows that this new approach can be successfully used to solve our optimization problem. To check the performance of our approach, it has been applied to five illustrative examples of different types, including open and closed 2D and 3D curves that exhibit challenging features, such as cusps and self-intersections. Our results show that the method performs pretty well, being able to solve our minimization problem in an astonishingly straightforward way.This research has been kindly supported by the Computer Science National Program of the Spanish Ministry of Economy and Competitiveness, Project Ref. no. TIN2012-30768, Toho University (Funabashi, Japan), and the University of Cantabria (Santander, Spain)

A Dynamic Kinetic Asymmetric Heck Reaction for the Simultaneous Generation of Central and Axial Chirality

A highly diastereo- and enantioselective, scalable Pd-catalyzed dynamic kinetic asymmetric Heck reaction of heterobiaryl sulfonates with electron-rich olefins is described. The coupling of 2,3-dihydrofuran or N-boc protected 2,3-dihydropyrrole with a variety of quinoline, quinazoline, phthalazine, and picoline derivatives takes place with simultaneous installation of central and axial chirality, reaching excellent diastereo- and enantiomeric excesses when in situ formed [Pd0/DM-BINAP] was used as the catalyst, with loadings reduced down to 2 mol % in large scale reactions. The coupling of acyclic, electron-rich alkenes can also be performed using a [Pd0/Josiphos ligand] to obtain axially chiral heterobiaryl α-substituted alkenes in high yields and enantioselectivities. Products from Boc-protected 2,3-dihydropyrrole can be easily transformed into N,N ligands or appealing axially chiral, bifunctional proline-type organocatalysts. Computational studies suggest that a β-hydride elimination is the stereocontrolling step, in agreement with the observed stereochemical outcome of the reaction.Ministerio de Ciencia e Innovación (Grants CTQ2016-76908-C2-1-P; CTQ2016-76908-C2-2-P; CTQ2016-78083-P; RYC-2013-12585)European Commission (FEDER Programme)Junta de Andalucía (Grant 2012/FQM 10787)Universidad de Sevilla (Grant No. 1800511201)European Union - Marie Skłodowska-Curie (COFUND—Grant Agreement nº 291780

Northern Shrimp (Pandalus borealis) on Flemish Cap Surveys 2005

Since 1988, a stratified random summer bottom trawl survey are being carried out in Flemish Cap (NAFO Regulatory Area of Division 3M) by UE. From 2003 the traditional research vessel Cornide de Saavedra was replaced by the R/V Vizconde de Eza. The new vessel was calibrated and the indexes transformed. In 2004 year, the lack of time has not permitted to transform the biomass and abundance shrimp indexes of the whole series and only the 2003 and 2004 indexes from the R/V Vizconde de Eza were transformed to the R/V Cornide de Saavedra scale. In this paper, the series from 1988 to 2002 obtained with the R/V Cornide the Saavedra were transformed to make them comparable to the results obtained with the new vessel R/V Vizconde de Eza. The results of shrimp from the last survey on Flemish Cap in 2005 are presented and compared to those from previous years of the same series. Both biomass and abundance have increased significantly due to increasing of 3 age-class. The female biomass decreased, mainly due to declining of 5 and 6 year-classes. Also, in recent years (2004 and 2005) the youngest specimens (age 1) didn't appear in the catches, and they were only presents in the small size bag on the codend

A new type of Na+-driven ATP synthase membrane rotor with a two-carboxylate ion-coupling motif

Abstract: The anaerobic bacterium Fusobacterium nucleatum uses glutamate decarboxylation to generate a transmembrane gradient of Na+. Here, we demonstrate that this ion-motive force is directly coupled to ATP synthesis, via an F1Fo-ATP synthase with a novel Na+ recognition motif, shared by other human pathogens. Molecular modeling and free-energy simulations of the rotary element of the enzyme, the c-ring, indicate Na+ specificity in physiological settings. Consistently, activity measurements showed Na+ stimulation of the enzyme, either membrane-embedded or isolated, and ATP synthesis was sensitive to the Na+ ionophore monensin. Furthermore, Na+ has a protective effect against inhibitors targeting the ion-binding sites, both in the complete ATP synthase and the isolated c-ring. Definitive evidence of Na+ coupling is provided by two identical crystal structures of the c11 ring, solved by X-ray crystallography at 2.2 and 2.6 Å resolution, at pH 5.3 and 8.7, respectively. Na+ ions occupy all binding sites, each coordinated by four amino acids and a water molecule. Intriguingly, two carboxylates instead of one mediate ion binding. Simulations and experiments demonstrate that this motif implies that a proton is concurrently bound to all sites, although Na+ alone drives the rotary mechanism. The structure thus reveals a new mode of ion coupling in ATP synthases and provides a basis for drug-design efforts against this opportunistic pathogen. Author Summary: Essential cellular processes such as biosynthesis, transport, and motility are sustained by the energy released in the hydrolysis of ATP, the universal energy carrier in living cells. Most ATP in the cell is produced by a membrane-bound enzyme, the ATP synthase, through a rotary mechanism that is coupled to the translocation of ions across the membrane. The majority of ATP synthases are energized by transmembrane electrochemical gradients of protons (proton-motive force), but a number of organisms, including some important human pathogens, use gradients of sodium ions instead (sodium-motive force). The ion specificity of ATP synthases is determined by a membrane-embedded sub-complex, the c-ring, which is the smallest known biological rotor. The functional mechanism of the rotor ring and its variations among different organisms are of wide interest, because of this enzyme's impact on metabolism and disease, and because of its potential for nanotechnology applications. Here, we characterize a previously unrecognized type of Na+-driven ATP synthase from the opportunistic human pathogen Fusobacterium nucleatum, which is implicated in periodontal diseases. We analyzed this ATP synthase and its rotor ring through a multi-disciplinary approach, combining cell-growth and biochemical assays, X-ray crystallography and computer-simulation methods. Two crystal structures of the membrane rotor were solved, at low and high pH, revealing an atypical ion-recognition motif mediated by two carboxylate side-chains. This motif is shared by other human pathogens, such as Mycobacterium tuberculosis or Streptococcus pneumonia, whose ATP synthases are targets of novel antibiotic drugs. The implications of this ion-recognition mode on the mechanism of the ATP synthase and the cellular bioenergetics of F. nucleatum were thus examined. Our results provide the basis for future pharmacological efforts against this important pathogen

Interface discontinuity factors in the modal eigenspace of the multigroup diffusion matrix

Interface discontinuity factors based on the Generalized Equivalence Theory are commonly used in nodal homogenized diffusion calculations so that diffusion average values approximate heterogeneous higher order solutions. In this paper, an additional form of interface correction factors is presented in the frame of the Analytic Coarse Mesh Finite Difference Method (ACMFD), based on a correction of the modal fluxes instead of the physical fluxes. In the ACMFD formulation, implemented in COBAYA3 code, the coupled multigroup diffusion equations inside a homogenized region are reduced to a set of uncoupled modal equations through diagonalization of the multigroup diffusion matrix. Then, physical fluxes are transformed into modal fluxes in the eigenspace of the diffusion matrix. It is possible to introduce interface flux discontinuity jumps as the difference of heterogeneous and homogeneous modal fluxes instead of introducing interface discontinuity factors as the ratio of heterogeneous and homogeneous physical fluxes. The formulation in the modal space has been implemented in COBAYA3 code and assessed by comparison with solutions using classical interface discontinuity factors in the physical spac

LGTBI culture in Spanish public libraries. Dialogue on new equality laws

The current relevance of LGTBI collections in public libraries is studied; these collections are included and prescribed in the recent laws for equality in Spanish regions such as Galicia, Catalonia, Extremadura, Madrid, Murcia, and Balearic Islands. After reflecting on the visibility of LGTBI authors and editorials, it is concluded that these collections are still scarce and that public libraries must learn about and incorporate information and documents that expand the social knowledge of sexual diversity