Titrimetric determination of zirconium

A brief literature survey on the present gravimetric, colorimetric, spectrographic, and volumetric methods for the determination of zirconium has been presented

Characterization of electrochemical systems using potential step voltammetry. Part II: Modeling of reversible systems

[EN] This study was carried out to compare the results obtained using potential step voltammetry and linear sweep voltammetry with a rotating gold disc electrode (RDE), when models based on equivalent circuits (EC) were used. The results lead to an equivalent circuit model that allows us to interpret the electrochemical behavior of aqueous solutions containing Fe(CN)(6)(-4) and Fe(CN)(6)(-3). With this model, we determined the values of the electrical resistance of the medium (R-s) as well as its polarization resistance (R-p), and established correlations between these values and the kinetic parameters of the system. The proposal highlights the need to introduce a new component for modeling using EC, which we have called the electrochemical diode. (C) 2019 Elsevier Ltd. All rights reserved.The authors gratefully acknowledge the financial support of BIA2016-78460-C3-3-R, MAT2015-64139-C4-3-R and RTI2018-100910-B-C43 (MINECO/FEDER) projects. We would also like to extend our appreciation for the pre-doctoral FPU scholarships (University Teacher Training scholarship) granted to Ana Martinez Ibernon (FPU 16/00723) and Jose Enrique Ramon Zamora (FPU13/00911) by the Spanish Ministry of Science and Innovation.Martínez-Ibernón, A.; Ramón Zamora, JE.; Gandía-Romero, JM.; Gasch, I.; Valcuende Payá, MO.; Alcañiz Fillol, M.; Soto Camino, J. (2019). Characterization of electrochemical systems using potential step voltammetry. Part II: Modeling of reversible systems. Electrochimica Acta. 328:1-10. https://doi.org/10.1016/j.electacta.2019.135111S11032

AxPcoords & parallel AxParafit: statistical co-phylogenetic analyses on thousands of taxa

Background Current tools for Co-phylogenetic analyses are not able to cope with the continuous accumulation of phylogenetic data. The sophisticated statistical test for host-parasite co-phylogenetic analyses implemented in Parafit does not allow it to handle large datasets in reasonable times. The Parafit and DistPCoA programs are the by far most compute-intensive components of the Parafit analysis pipeline. We present AxParafit and AxPcoords (Ax stands for Accelerated) which are highly optimized versions of Parafit and DistPCoA respectively. Results Both programs have been entirely re-written in C. Via optimization of the algorithm and the C code as well as integration of highly tuned BLAS and LAPACK methods AxParafit runs 5–61 times faster than Parafit with a lower memory footprint (up to 35% reduction) while the performance benefit increases with growing dataset size. The MPI-based parallel implementation of AxParafit shows good scalability on up to 128 processors, even on medium-sized datasets. The parallel analysis with AxParafit on 128 CPUs for a medium-sized dataset with an 512 by 512 association matrix is more than 1,200/128 times faster per processor than the sequential Parafit run. AxPcoords is 8–26 times faster than DistPCoA and numerically stable on large datasets. We outline the substantial benefits of using parallel AxParafit by example of a large-scale empirical study on smut fungi and their host plants. To the best of our knowledge, this study represents the largest co-phylogenetic analysis to date. Conclusion The highly efficient AxPcoords and AxParafit programs allow for large-scale co-phylogenetic analyses on several thousands of taxa for the first time. In addition, AxParafit and AxPcoords have been integrated into the easy-to-use CopyCat tool

Competing values in public management

The main objective of the article is to review relevant literature on (competing) public values in public management and to present a number of perspectives on how to deal with value conflicts in different administrative settings and contexts. We start this symposium with the assumption that value conflicts are prevalent, the public context can be characterized by value pluralism, and instrumental rationality does not seem to be the most useful to understand or improve value conflicts in public governance. This begs the question: what is the best way to study and manage value conflicts? The contributions to this symposium issue approach value conflicts in public governance from different perspectives, within different countries and different administrative and management systems, hoping to contribute to the debate on how to deal with important yet conflicting public values in public management, without pretending to offer a conclusive strategy or approach. This introductory article also presents and reviews the contributions to this symposium issue. © 2011 Taylor & Francis

Still Something to Discover: Novel Insights into Escherichia coli Phage Diversity and Taxonomy

The aim of this study was to gain further insight into the diversity of Escherichia coli phages followed by enhanced work on taxonomic issues in that field. Therefore, we present the genomic characterization and taxonomic classification of 50 bacteriophages against E. coli isolated from various sources, such as manure or sewage. All phages were examined for their host range on a set of different E. coli strains, originating, e.g., from human diagnostic laboratories or poultry farms. Transmission electron microscopy revealed a diversity of morphotypes (70% Myo-, 22% Sipho-, and 8% Podoviruses), and genome sequencing resulted in genomes sizes from ~44 to ~370 kb. Annotation and comparison with databases showed similarities in particular to T4- and T5-like phages, but also to less-known groups. Though various phages against E. coli are already described in literature and databases, we still isolated phages that showed no or only few similarities to other phages, namely phages Goslar, PTXU04, and KWBSE43-6. Genome-based phylogeny and classification of the newly isolated phages using VICTOR resulted in the proposal of new genera and led to an enhanced taxonomic classification of E. coli phages

Results of the ontology alignment evaluation initiative 2017

Ontology matching consists of finding correspondences between semantically related entities of different ontologies. The Ontology Alignment Evaluation Initiative (OAEI) aims at comparing ontology matching systems on precisely defined test cases. These test cases can be based on ontologies of different levels of complexity (from simple thesauri to expressive OWL ontologies) and use different evaluation modalities (e.g., blind evaluation, open evaluation, or consensus). The OAEI 2017 campaign offered 9 tracks with 23 test cases, and was attended by 21 participants. This paper is an overall presentation of that campaign