A Geometric Framework for Investigating the Multiple Unicast Network Coding Conjecture

The multiple unicast network coding conjecture states that for multiple unicast sessions in an undirected network, network coding is equivalent to routing. Simple and intuitive as it appears, the conjecture has remained open since its proposal in 2004 [1], [2], and is now a well-known unsolved problem in the field of network coding. Based on a recently proposed tool of space information flow [3]-[5], we present a geometric framework for analyzing the multiple unicast conjecture. The framework consists of four major steps, in which the conjecture is transformed from its throughput version to cost version, from the graph domain to the space domain, and then from high dimension to 1-D, where it is to be eventually proved. We apply the geometric framework to derive unified proofs to known results of the conjecture, as well as new results previously unknown. A possible proof to the conjecture based on this framework is outlined.published_or_final_versio

Ter ou ser? Eis a questão: O efeito moderador das características de personalidade sobre a relação entre o person-job fit e o engagement

Dissertação de Mestrado apresentada ao ISPA - Instituto UniversitárioO presente estudo tem como objetivo verificar não só o impacto da Sobrequalificação sobre o Engagement no Trabalho, mas também explorar o efeito moderador das Características da Personalidade na relação entre a Sobrequalificação e o Engagement no Trabalho. A amostra é constituída por 562 participantes, que trabalham em diferentes Empresas/Organizações há pelo menos 1 ano e têm idades compreendidas entre os 18 e os 64 anos. De forma a medir a Sobrequalificação, foi utilizada a escala proposta por Johson, Morrow e Johnson (2002) - POQ - Perceived Overqualification Scale - traduzida e adaptada à cultura Portuguesa por três professores com domínio na língua inglesa e psicólogos organizacionais; o Engagement no Trabalho foi medido pela Utrecht Work Engagement Scale (Schaufeli & Bakker, 2003), adaptada por Marques Pinto (2007); e as Características da Personalidade foram medidas através da versão portuguesa da escala BFI-10 - Big Five Inventory - 10 Item Short Version (Rammstedt & John, 2007), adaptada por Bártolo-Ribeiro e Aguiar (2008). Os resultados confirmam a relação entre a dimensão percepção de não crescimento da sobrequalificação e o engagement no trabalho, sendo esta relação negativa, o que quer dizer que, à medida que a percepção de não crescimento aumenta, dimimui o engagement no trabalho. Já o efeito moderador das características de personalidade na relação entre a percepção de não crescimento e o engagement no trabalho não se verificou. Ainda assim, apurou-se que o Neuroticismo tem um efeito negativo e significativo sobre o engagement e a Conscienciosidade tem um efeito positivo e significativo sobre o engagement. Tendo sido feita uma análise complementar, utilizando-se as dimensões do engagement (Vigor, Dedicação e Absorção), verificou-se que a Extroversão modera a relação entre a percepção de não crescimento e o Vigor, isto é, quanto mais elevada for a extroversão, maior será o vigor em situações de baixa percepção de não crescimento.ABSTRACT: The present study aims to investigate the influence of Overqualification in individual’s Work Engagement, as well as explore the moderation effect of Personality Traits in the relationship between Overqualification and Work Engagement. The study sample analysed 562 participants, working on different companies/organizations for at least one year, aged between 18 and 64 years. Overqualification was measured using POQ - Perceived Overqualification Scale (Johnson et al., 2002) - translated and adapted to the portuguese culture, by three universitary teachers with domain in english language and organizational Psychologists; Work Engagement was measured using the Utrecht Work Engagement Scale (Schaufeli & Bakker, 2003), adapted by Marques Pinto (2007); and the Personality Traits were measured using the BFI-10 - Big Five Inventory - 10 Item Short Version (Rammstedt & John, 2007), adapted by Bártolo-Ribeiro e Aguiar (2008). The results confirm a negative and significant relationship between the dimension perceived no-growth of overqualification and work engagement. These results demonstrate that the more the workers perceived no-growth, the less work engagement they experience. The hypothesis of moderator effect of the personality traits on the relationship between perceived no-growth and work engagement was not confirmed. Even so, it was found that Neuroticism had a negative and significant effect on work engagement, and Conscientiousness had a positive and significant effect on work engagement. Having been made a complementary analysis, with work engagement dimensions (Vigor, Dedication and Absorption), we found that Extroversion moderates the relationship between perceived nogrowth and Vigor. It means that, if workers are more Extraverted, more will be the vigor, in situations with low perception of no-growth

Genetic analysis of walnut cultivars from southwest China:Implications for germplasm improvement

Walnuts are highly valued for their rich nutritional profile and wide medicinal applications. This demand has led to the intensification of breeding activities in major walnut production areas such as southwest China, in order to develop more superior cultivars. With the increasing number of cultivars, accurate identification becomes fundamental to selecting the right cultivar for grafting, industrial processing or development of new cultivars. To ensure proper identification of cultivars and understand the genetic structure of wild and cultivated material, we genotyped 362 cultivated and wild individuals of walnut trees from southwest China (with two additional populations from Xinjiang, plus three cultivars from Canada, France and Belgium) using 36 polymorphic microsatellite loci. We found relatively low indices of genetic diversity (H(O) = 0.570, H(E) = 0.404, N(A) = 2.345) as well as a high level of clonality (>85% of cultivars), indicating reliance on genetically narrow sources of parental material for breeding. Our STRUCTURE and PCoA analyses generally delineated the two species, though considerable levels of introgression were also evident. More significantly, we detected a distinct genetic group of cultivated Juglanssigillata, which mainly comprised individuals of the popular ‘Yangbidapao’ landrace. Finally, a core set of 18 SSR loci was selected, which was capable of identifying 32 cultivars. In a nutshell, our results call for more utilization of genetically disparate material, including wild walnut trees, as parental sources to breed for more cultivars. The data reported herein will significantly contribute towards the genetic improvement and conservation of the walnut germplasm in southwest China

Computer software for understanding resonances and resonance-related phenomena in chemical reactions

In numerical modelling of chemical reactions one calculates the scattering matrix for the required values of energy and angular momentum. Having done so, one still faces the non-trivial task of extracting detailed information about the reaction mechanism. We discuss the methods and numerical tools for such an analysis in terms of resonance poles and semiclassical trajectories. Our approach avoids calculating the scattering matrix in semiclassical approximation, and employs its numerical values computed previously by an accurate scattering code

A Multiplex PCR System of Novel Microsatellite Loci for Population Genetic Application in Walnuts

Multiplex polymerase chain reaction (PCR) of microsatellite loci allows for simultaneous amplification of two or more pairs of primers in a single PCR reaction; hence, it is cost and time effective. However, very few attempts have been reported in non-model species. In this study, by combining a genome-based de novo development and cross-species application approach, a multiplex PCR system comprising 5 PCR reactions of 33 microsatellites consisting of 26 novel genomic and 7 literature-sourced loci was tested for polymorphisms, cross-species transferability, and the ability to assess genetic diversity and population structure of three walnut species (Juglans spp.). We found that the genome-based approach is more efficient than other methods. An allelic ladder was developed for each locus to enhance consistent genotyping among laboratories. The population genetic analysis results showed that all 33 loci were successfully transferred across the three species, showing high polymorphism and a strong genetic structure. Hence, the multiplex PCR system is highly applicable in walnut species. Furthermore, we propose an efficient pipeline to characterize and genotype polymorphic microsatellite loci. The novel toolbox developed here will aid future ecology and evolution studies in walnut and could serve as a model for other plant species