Distribución espacial de leguminosas en relación con el arbolado

A study was made of tree canopy influence on spatial distribution of leguminosae species and some soil variables in grassland communities. Besides the differentiation according to the tree species, it is possible to establish groups of samples according to their distance frorn the tree trunk. The greatest influence of canopy on vegetation and soil variables has been detected in the samples taken on the northern side of the trees.Se estudia la incidencia del arbolado sobre la distribución espacial de especies pertenecientes a la familia de las leguminosas y sobre algunas variables edáficas, en comunidades de pastizal adehesado. Aparte de la diferenciación atribuible a la especie arbórea, en todos los casos es posible el establecimiento de grupos de acuerdo con la distancia al tronco. La mayor influencia del arbolado se detecta en orientación norte, tanto en lo que se refiere a la vegetación como a las variables edíficas

Topological Hunds rules and the electronic properties of a triple lateral quantum dot molecule

We analyze theoretically and experimentally the electronic structure and charging diagram of three coupled lateral quantum dots filled with electrons. Using the Hubbard model and real-space exact diagonalization techniques we show that the electronic properties of this artificial molecule can be understood using a set of topological Hunds rules. These rules relate the multi-electron energy levels to spin and the inter-dot tunneling $t$, and control charging energies. We map out the charging diagram for up to N=6 electrons and predict a spin-polarized phase for two holes. The theoretical charging diagram is compared with the measured charging diagram of the gated triple-dot device.Comment: 31 pages, 7 figures, accepted to March 15, 2007 issue of Phys. Rev. B, vol. 7

BiFC and CRISPR-dCpf1, a new tool to study DNA-proteins interactions

Motivation: CRISPR based systems allow directing a protein (Cpf1) to specific genome regions guided by a small RNA molecule (known as sgRNA), which leads Cpf1 to a specific DNA sequence. We are using this system in combination with the Bimolecular fluorescence complementation (BiFC) to monitor DNA-Protein interactions. This new system consists in tagging a fragment of YFP to the endonuclease dead dCpf1 which, by the action of the sgRNA previously designed, will still be guided to the specific DNA sequence without making the dsb. On the other hand, another native know to interact with the same region is tagged to the other YFP fragment. The interaction between the protein and that specific sequence would allow the association of the fragments produce a bimolecular fluorescent complex. This proof-of-principle to monitor DNA-Protein (and eventually DNA-DNA) interactions will allow genome dinamics studies in vivo. Methods: We will use a dead version of the CRISPR based Cpf1 nuclease in combination with BiFC. We will obtain dCpf1 using a directed mutagenesis mechanism by PCR from the pMZCpf1. To validate the system we will first direct the dCpf1-YFP fusion to the centromeres, as a control region of the genome. This fusion will be created by overlapping PCR and also we will put it under the regulation of a medium strength promotor (nmt41), flanked by both halves of the Hygromycin resistance gene. We will integrate this cassette into a Hygromicin resistant strain by homologous recombination. We will obtain the specific sgRNA, which will guide Cpf1-YFP to the centromeres. To show proper localization we will use a cnp1-mCherry (centromeric protein) to assess co-localization. Once validated that level, we will split YFP by tagging the two proteins (dCpf1 and Cnp1) to validate biFC system.Conclusions: The development of this system provides a great tool that would enable observing DNA- proteins interactions with a huge precision. With regards to the future, several sgRNAs could be generated to study interactions of proteins with multiple sequences of a genome.This would allow to study genomic loci dynamics and nuclear topology in vivo

Some Probabilistic Results in a Bisexual Branching Process with Immigration

2000 Mathematics Subject Classification: 60J80.A bisexual branching process with immigration of females and males is introduced. It is allowed, in each generation, that the mating function and the probability distributions associated to the offspring and the immigration may change depending on the number of progenitor couples. Relationships among the probability generating functions involved in the model and some transition and stochastic monotony properties are established.This research has been supported by the Ministerio de Ciencia y Tecnologia and the FEDER through the Plan Nacional de Investigacion Cientifica, Desarrollo e Innovaci on Tecnologica, grant BFM2003-06074

Unitary Owen Points in Cooperative Lot-Sizing Models with Backlogging

This paper analyzes cost sharing in uncapacitated lot-sizing models with backlogging and heterogeneous costs. It is assumed that several firms participate in a consortium aiming at satisfying their demand over the planning horizon with minimal operating cost. Each individual firm has its own ordering channel and holding technology, but cooperation with other firms consists in sharing that information. Therefore, the firms that cooperate can use the best ordering channels and holding technology among members of the consortium. This mode of cooperation is stable. in that allocations of the overall operating cost exist, so that no group of agents benefit from leaving the consortium. Our contribution in the current paper is to present a new family of cost sharing allocations with good properties for enforcing cooperation: the unitary Owen points. Necessary and sufficient conditions are provided for the unitary Owen points to belong to the core of the cooperative game. In addition, we provide empirical evidence, through simulation, showing that, in randomly-generated situations, the above condition is fulfilled in 99% of the cases. Additionally, a relationship between lot-sizing games and a certain family of production-inventory games, through Owen’s points of the latter, is described. This interesting relationship enables easily constructing a variety of coalitionally stable allocations for cooperative lot-sizing models.The research authors is supported from Spain’s Ministerio de Ciencia, Innovación y Universidades (MCIU), from the Agencia Estatal de Investigación (AEI) and from the Fondo Europeo de Desarrollo Regional (FEDER) under the projects MTM2016-74983-C02-01 and PGC2018-097965-B-I00. The research of the third author is also partially supported from projects FEDER-US-1256951, CEI-3-FQM331 and NetmeetData: Ayudas Fundación BBVA a equipos de investigación científica 2019

An extended version of the Ordered Median Tree Location Problem including appendices and detailed computational results

In this paper, we propose the Ordered Median Tree Location Problem (OMT). The OMT is a single-allocation facility location problem where p facilities must be placed on a network connected by a non-directed tree. The objective is to minimize the sum of the ordered weighted averaged allocation costs plus the sum of the costs of connecting the facilities in the tree. We present different MILP formulations for the OMT based on properties of the minimum spanning tree problem and the ordered median optimization. Given that ordered median hub location problems are rather difficult to solve we have improved the OMT solution performance by introducing covering variables in a valid reformulation plus developing two pre-processing phases to reduce the size of this formulations. In addition, we propose a Benders decomposition algorithm to approach the OMT. We establish an empirical comparison between these new formulations and we also provide enhancements that together with a proper formulation allow to solve medium size instances on general random graphs.Comment: 112 pages, 4 figures, extended version of 'The Ordered Median Location Problem