505 research outputs found

    The bicompletion of the Hausdorff quasi-uniformity

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    We study conditions under which the Hausdorff quasi-uniformity UH{\mathcal U}_H of a quasi-uniform space (X,U)(X,{\mathcal U}) on the set P0(X){\mathcal P}_0(X) of the nonempty subsets of XX is bicomplete. Indeed we present an explicit method to construct the bicompletion of the T0T_0-quotient of the Hausdorff quasi-uniformity of a quasi-uniform space. It is used to find a characterization of those quasi-uniform T0T_0-spaces (X,U)(X,{\mathcal U}) for which the Hausdorff quasi-uniformity U~H\widetilde{{\mathcal U}}_H of their bicompletion (X~,U~)(\widetilde{X},{\widetilde{\mathcal U}}) on P0(X~){\mathcal P}_0(\widetilde{X}) is bicomplete

    A quantitative version of Krein's theorems for Fréchet spaces

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    For a Banach space E and its bidual space E'', the function k(H) defined on bounded subsets H of E measures how far H is from being &#963;(E,E')-relatively compact in E. This concept, introduced independently by Granero, and Cascales et al., has been used to study a quantitative version of Krein¿s theorem for Banach spaces E and spaces Cp(K) over compact K. In the present paper, a quantitative version of Krein¿s theorem on convex envelopes coH of weakly compact sets H is proved for Fréchet spaces, i.e. metrizable and complete locally convex spaces. For a Fréchet space E, the above function k(H) has been defined in thisi paper by menas of d(h,E) is the natural distance of h to E in the bidual E''. The main result of the paper is the following theorem: For a bounded set H in a Fréchet space E, the following inequality holds k(coH) < (2^(n+1) &#8722; 2)k(H) + 1/2^n for all n &#8712; N. Consequently, this yields also the following formula k(coH) &#8804; (k(H))^(1/2))(3-2(k(H)^(1/2))). Hence coH is weakly relatively compact provided H is weakly relatively compact in E. This extends a quantitative version of Krein¿s theorem for Banach spaces (obtained by Fabian, Hajek, Montesinos, Zizler, Cascales, Marciszewski, and Raja) to the class of Fréchet spaces. We also define and discuss two other measures of weak non-compactness lk(H) and k'(H) for a Fréchet space and provide two quantitative versions of Krein¿s theorem for both functions.The research was supported for C. Angosto by the project MTM2008-05396 of the Spanish Ministry of Science and Innovation, for J. Kakol by National Center of Science, Poland, Grant No. N N201 605340, and for M. Lopez-Pellicer by the project MTM2010-12374-E (complementary action) of the Spanish Ministry of Science and Innovation.Angosto Hernández, C.; Kakol, J.; Kubzdela, A.; López Pellicer, M. (2013). A quantitative version of Krein's theorems for Fréchet spaces. Archiv der Mathematik. 101(1):65-77. https://doi.org/10.1007/s00013-013-0513-4S65771011Angosto C., Cascales B.: Measures of weak noncompactness in Banach spaces. Topology Appl. 156, 1412–1421 (2009)C. Angosto, Distance to spaces of functions, PhD thesis, Universidad de Murcia (2007).C. Angosto and B. Cascales, A new look at compactness via distances to functions spaces, World Sc. Pub. Co. (2008).Angosto C., Cascales B.: The quantitative difference between countable compactness and compactness. J. Math. Anal. Appl. 343, 479–491 (2008)Angosto C., Cascales B., Namioka I.: Distances to spaces of Baire one functions. Math. Z. 263, 103–124 (2009)C. Angosto, J. Ka̧kol, and M. López-Pellicer, A quantitative approach to weak compactness in Fréchet spaces and spaces C(X), J. Math. Anal. Appl. 403 (2013), 13–22.Cascales B., Marciszesky W., Raja M.: Distance to spaces of continuous functions. Topology Appl. 153, 2303–2319 (2006)M. Fabian et al. Functional Analysis and Infinite-dimensional geometry, CMS Books in Mathematics, Canadian Math. Soc., Springer (2001).M. Fabian et al. A quantitative version of Krein’s theorem, Rev. Mat. Iberoam. 21 (2005), 237–248Granero A. S.: An extension of the Krein-Smulian Theorem. Rev. Mat. Iberoam. 22, 93–110 (2006)Granero A. S., Hájek P., Montesinos V.: Santalucía, Convexity and ω*-compactness in Banach spaces. Math. Ann. 328, 625–631 (2004)Grothendieck A.: Criteres de compacité dans les spaces fonctionnelles généraux. Amer. J. Math. 74, 168–186 (1952)Khurana S. S.: Weakly compactly generated Fréchet spaces. Int. J. Math. Math. Sci. 2, 721–724 (1979

    Genomic Population Structure of the Main Historical Genetic Lines of Spanish Merino Sheep

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    According to historiographical documentation, the Romans first began to select Merino sheep in the Iberian Peninsula during the first century, with the aim of obtaining a breed appreciated for the quality of its wool. This process continued locally during the Middle Ages, when Spanish sheep were protected, and their export to foreign countries was banned. It was during the 16th century when individual Merino sheep were allowed to spread around the world to be used to improve the wool quality of local breeds. However, the wool crisis of the 1960s shifted the selection criteria of the Merino breed towards meat production at the expenses of wool. Consequently, individuals that display the genetic and phenotypic characteristics of those sheep originally bred in the kingdom of Spain in the Middle Ages are extremely difficult to find in commercial herds. In this study, we characterized the genetic basis of 403 individuals from the main historical Spanish Merino genetic lines (Granda, Hidalgo, Lopez-Montenegro, Maeso, Donoso and Egea), which were bred in isolation over the last 200 years, using a genomic approach based on genotyping data from the Axiom™ Ovine 50 K SNP Genotyping Array. Our analysis included measuring population structure, genomic differentiation indexes, runs of homozygosity (ROH) patterns, and an analysis of molecular variance (AMOVA). The results showed large genetic differences between the historical lines, even though they belong to the same breed. In addition, ROH analysis showed differences due to increased inbreeding among the ancient generations compared with the modern Merino lines, confirming the breed’s ancestral and closed origin. However, our results also showed a high variability and richness within the Spanish historical Merino lines from a genetic viewpoint. This fact, together with their great ability to produce high-quality wool, suggests that ancestral Merino lines from Spain should be considered a valuable genetic population to be maintained as a resource for the improvement of wool-producing sheep breeds all around the world

    Business Process Re-engineering in Public Administration: The case study of Western Ligurian Sea Port Authority

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    Business Process Re-engineering (BPR) is a technique based on a radical redesign of the structure of an organization to improve its efficiency by optimizing processes and reducing costs. It has been proven effective over a plethora of private applications however, not many studies based on the public sector have been reported even though it is known to be inefficient. This is mainly due to an overall smaller market exposure of public administrations compared to private companies. However, nowadays, in the age of digitalization, the growing global competition is requiring PA to improve the efficiency of their processes. This paper offers a real case-study of an application of BPR in a PA namely the Genoa Port in Italy, one of the biggest ports in Europe. The following analysis has been carried out through an AS IS / TO BE approach and the outcome of the re-engineering process has been validated through Discrete Event Simulation. The results show how BPR can improve the efficiency of PAs and, particularly, how the port environment can drastically turn into an efficient and optimized system

    AmrZ is a major determinant of c-di-GMP levels in Pseudomonas fluorescens F113

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    The transcriptional regulator AmrZ is a global regulatory protein conserved within the pseudomonads. AmrZ can act both as a positive and a negative regulator of gene expression, controlling many genes implicated in environmental adaption. Regulated traits include motility, iron homeostasis, exopolysaccharides production and the ability to form biofilms. In Pseudomonas fluorescens F113, an amrZ mutant presents a pleiotropic phenotype, showing increased swimming motility, decreased biofilm formation and very limited ability for competitive colonization of rhizosphere, its natural habitat. It also shows different colony morphology and binding of the dye Congo Red. The amrZ mutant presents severely reduced levels of the messenger molecule cyclic-di-GMP (c-di-GMP), which is consistent with the motility and biofilm formation phenotypes. Most of the genes encoding proteins with diguanylate cyclase (DGCs) or phosphodiesterase (PDEs) domains, implicated in c-di-GMP turnover in this bacterium, appear to be regulated by AmrZ. Phenotypic analysis of eight mutants in genes shown to be directly regulated by AmrZ and encoding c-di-GMP related enzymes, showed that seven of them were altered in motility and/or biofilm formation. The results presented here show that in P. fluorescens, AmrZ determines c-di-GMP levels through the regulation of a complex network of genes encoding DGCs and PDEs

    Design and validation of a three-instrument toolkit for the assessment of competence in electrocardiogram rhythm recognition

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    Background: Rapid and accurate interpretation of cardiac arrhythmias by nurses has been linked with safe practice and positive patient outcomes. Although training in electrocardiogram (ECG) rhythm recognition is part of most undergraduate nursing programmes, research continues to suggest that nurses and nursing students lack competence in recognising cardiac rhythms. In order to promote patient safety, nursing educators must develop valid and reliable assessment tools that allow the rigorous assessment of this competence before nursing students are allowed to practise without supervision. Aim: To develop and psychometrically evaluate a toolkit to holistically assess competence in ECG rhythm recognition. Methods: Following a convenience sampling technique, 293 nursing students from a nursing faculty in a Spanish university were recruited for the study. The following three instruments were developed and psychometrically tested: a knowledge assessment tool (ECG-KAT), a skills assessment tool (ECG-SAT) and a self-efficacy assessment tool (ECG-SES). Reliability and validity (content, criterion and construct) of these tools were meticulously examined. Results: A high Cronbach’s alpha coefficient demonstrated the excellent reliability of the instruments (ECG-KAT=0.89; ECG-SAT=0.93; ECG-SES=0.98). An excellent context validity index (S-CVI/Ave>0.94) and very good criterion validity were evidenced for all the tools. Regarding construct validity, principal component analysis revealed that all items comprising the instruments contributed to measure knowledge, skills or self-efficacy in ECG rhythm recognition. Moreover, known-groups analysis showed the tools’ ability to detect expected differences in competence between groups with different training experiences. Conclusion: The three-instrument toolkit developed showed excellent psychometric properties for measuring competence in ECG rhythm recognition

    Is food addiction a predictor of treatment outcome among patients with eating disorder?

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    ObjectivesThe study aimed to examine whether food addiction (FA) was associated with greater severity in both binge eating disorders (BED) and bulimia nervosa and, therefore, to determine if FA was predictive of treatment outcome.MethodSeventy-one adult patients with bulimia nervosa and BED (42 and 29, respectively) participated in the study. FA was assessed by means of the Yale Food Addiction Scale.ResultsThe results confirmed a high prevalence of FA in patients with binge disorders (around 87%) and also its association with a greater severity of the disorder (i.e., related to an increased eating psychopathology and greater frequency of binge eating episodes). Although FA did not appear as a predictor of treatment outcome in general terms, when the diagnostic subtypes were considered separately, FA was associated with poor prognosis in the BED group. In this vein, FA appeared as a mediator in the relationship between ED severity and treatment outcome.DiscussionsOur findings suggest that FA may act as an indicator of ED severity, and it would be a predictor of treatment outcome in BED but not in BN.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152018/1/erv2705.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152018/2/erv2705_am.pd
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