Classical properties of algebras using a new graph association

We study the relation between algebraic structures and Graph Theory. We have defined five different weighted digraphs associated to a finite dimensional algebra over a field in order to tackle important properties of the associated algebras, mainly the nilpotency and solvability in the case of Leibniz algebras

Adaptive clinical trials incorporating treatment selection and evaluation: methodology and application in progressive multiple sclerosis

In progressive multiple sclerosis (MS) irreversible disability often takes many years to accumulate as a result prolonged trials are required to assess the benefits of therapies. There is a need to understand the relationship between short-term outcome measures such as MRI endpoints and long-term clinical outcomes in progression to determine the evolution of the disease early on. Thus, the common phase I-II-III paradigm for clinical trial design with separate trials for each phase may not be appropriate

Learning from R&D outsourcing vs. learning by R&D outsourcing

We analyze how research and development (R&D) outsourcing influences product innovation. We propose a separation between learning from R&D outsourcing, whereby the firm improves its ability to innovate by using outsourced R&D directly in new products, from learning by R&D outsourcing, whereby the firm indirectly uses outsourced R&D by integrating it with internal R&D to create new products. Building on the knowledge-based view, we argue that learning from R&D outsourcing is likely to have an inverse U-shaped relationship with product innovation, because the initial benefits of using outsourced component R&D knowledge to innovate products is eventually outweighed by the hollowing out of the firm's ability to innovate. In contrast, we propose that learning by R&D outsourcing is likely to have a U-shaped relationship with product innovation, because the initial challenges of integrating internal and external R&D are eventually overcome, resulting in more innovations. Finally, we distinguish between domestic and foreign R&D outsourcing and propose a liability of foreignness in R&D outsourcing as it has a lower impact on new products than domestic R&D outsourcing. The empirical analysis shows that outsourced R&D has an inverted U-shaped relationship with the number of new products, while the interaction between outsourced R&D and internal R&D has a U-shaped relationship with the number of new products. It also shows that domestic outsourced R&D has a higher positive impact on the number of new products than foreign outsourced R&D.Ministry of Economy and Competitiveness of Spain (Grant: ECO2015-67296-R, MINECO/FEDER, UE), the Community of Madrid and the European Social Fund (S2015/HUM-3417 and INNCOMCON-CM) for their support of this project. Finally, for financial support, Un thanks the D'Amore-McKim School of Business of Northeastern University for the Strategic Summer Research Award, and Rodriguez thanks the Ramon Areces Foundation CISP15A3196

Exploration of Solar Cosmic Ray Sources by Means of Particle Energy Spectra

Through the analysis of the energy spectrum of 12 ground level enhancements (GLE) of solar protons, a contribution in the understanding of the generation process of flare particles is attempted. Theoretical spectra of protons are derived by considering either they do not lose energy within the acceleration volume or that they are decelerated during the acceleration process. By comparing the theoretical source spectra with the experimental spectra, it is claimed that the generation process of solar particles develops under three main temperature regimes: the efficiency of particles acceleration is relatively high in cold-regimens decreasing while increasing the temperature of the medium. It is shown that in some events energy losses are able to modulate the acceleration spectrum within the source during the short time scale of the phenomenon, whereas in other events energy losses are completely negligible during the acceleration. It is argued that acceleration takes place in closed magnetic field lines and predicted the expansion and compression of the source material in association with the generation process of particles. This study allows us to estimate the range of variation from event to event of several parameters of the source and the acceleration process itself

El significado social que los jóvenes universitarios mexicanos tienen del celular. Un análisis desde la perspectiva de género

En esta nueva realidad social, la juventud se acompasa de forma natural a los cambios acelerados, a diferencia de los adultos “que se resisten a la celeridad de los cambios por el cúmulo de hábitos, prácticas y conocimientos ya incorporados” (Zermeño, 2002: 29). Por otro lado, los jóvenes tienen como reto natural de su etapa de desarrollo, lo que Erikson llamó “generatividad”, la capacidad para ser productivo y creativo (Citado en Donas, 2001). Y las nuevas reglas del juego están caracterizadas por una realidad social en donde el acceso al conocimiento y a la información son los ejes claves para el desarrollo social de los jóvenes (Castells, 2000). En este sentido, desde la sociología y la comunicación reflexionamos respecto al significado social que los jóvenes universitarios tienen del celular, tomando en cuenta la perspectiva de género. Para ello, el trabajo está organizado en cinco apartados. En el primero se hace una introducción del tema estudiado. En el segundo se hace una revisión teórico-conceptual de las perspectivas teóricas desde donde se comprenden las categorías: significado social, jóvenes universitarios y celular. En el tercero se explica la estrategia metodológica que se empleo para obtener la evidencia empírica. En el cuarto, se expone el significado social que los jóvenes universitarios tienen del celular tomando en cuenta la perspectiva de género. Y finalmente, en el quinto apartado se hacen las reflexiones finales sobre los hallazgos

The AMIGA sample of isolated galaxies. IV. A catalogue of neighbours around isolated galaxies

Studies of the effects of environment on galaxy properties and evolution require well defined control samples. Such isolated galaxy samples have up to now been small or poorly defined. The AMIGA project (Analysis of the interstellar Medium of Isolated GAlaxies) represents an attempt to define a statistically useful sample of the most isolated galaxies in the local (z < 0.05) Universe. A suitable large sample for the AMIGA project already exists, the Catalogue of Isolated Galaxies (CIG, Karachentseva 1973; 1050 galaxies), and we use this sample as a starting point to refine and perform a better quantification of its isolation properties. Digitised POSS-I E images were analysed out to a minimum projected radius R > 0.5 Mpc around 950 CIG galaxies (those within Vr = 1500 km s-1 were excluded). We identified all galaxy candidates in each field brighter than B = 17.5 with a high degree of confidence using the LMORPHO software. We generated a catalogue of approximately 54 000 potential neighbours (redshifts exist for 30% of this sample). Six hundred sixty-six galaxies pass and two hundred eighty-four fail the original CIG isolation criterion. The available redshift data confirm that our catalogue involves a largely background population rather than physically associated neighbours. We find that the exclusion of neighbours within a factor of four in size around each CIG galaxy, employed in the original isolation criterion, corresponds to Delta Vr ~ 18000 km s-1 indicating that it was a conservative limit. Galaxies in the CIG have been found to show different degrees of isolation. We conclude that a quantitative measure of this is mandatory. It will be the subject of future work based on the catalogue of neighbours obtained here.Comment: Accepted by A&A, 10 pages, 8 figures, 4 table

Diversity of plant growth-promoting bacteria associated with sugarcane

The sugarcane (Saccharum spp) presents economic importance, mainly for tropical regions, being an important Brazilian commodity. However, this crop is strongly dependent on fertilizers, mainly nitrogen (N). This study assessed the plant growth-promoting bacteria (PGPB) associated with sugarcane that could be used as a potential inoculant to the crop. We evaluated the genetic diversity of PGPB in the plant tissue of sugarcane varieties (RB 867515, RB 1011, and RB 92579). The primer BOX-A1R was used to differentiate the similar isolated and further sequencing 16S rRNA ribosomal gene. The 16S rRNA gene showed the presence of seven different genera distributed into four groups, the genus Bacillus, followed by Paenibacillus (20%), Burkholderia (14%), Herbaspirillum (6%), Pseudomonas (6%), Methylobacterium (6%), and Brevibacillus (3%). The molecular characterization of endophytic isolates from sugarcane revealed a diversity of bacteria colonizing this plant, with a possible biotechnological potential to be used as inoculant and biofertilizers