Magnetism and Heterogeneous Catalysis: In Depth on the Quantum Spin-Exchange Interactions in Pt3M (M = V, Cr, Mn, Fe, Co, Ni, and Y)(111) Alloys

Bimetallic Pt-based alloys have drawn considerable attention in the last decades as catalysts in proton-exchange membrane fuel cells (PEMFCs) because they closely fulfill the two major requirements of high performance and good stability under operating conditions. Pt3Fe, Pt3Co, and Pt3Ni stand out as major candidates, given their good activity toward the challenging oxygen reduction reaction (ORR). The common feature across catalysts based on 3d-transition metals and their alloys is magnetism. Ferromagnetic spin-electron interactions, quantum spin-exchange interactions (QSEIs), are one of the most important energetic contributions in allowing milder chemisorption of reactants onto magnetic catalysts, in addition to spin-selective electron transport. The understanding of the role played by QSEIs in the properties of magnetic 3d-metal-based alloys is important to design and develop novel and effective electrocatalysts based on abundant and cheap metals. We present a detailed theoretical study (via density functional theory) on the most experimentally explored bimetallic alloys Pt3M (M = V, Cr, Mn, Fe, Co, Ni, and Y)(111). The investigation starts with a thorough structural study on the composition of the layers, followed by a comprehensive physicochemical description of their resistance toward segregation and their chemisorption capabilities toward hydrogen and oxygen atoms. Our study demonstrates that Pt3Fe(111), Pt3Co(111), and Pt3Ni(111) possess the same preferential multilayered structural organization, known for exhibiting specific magnetic properties. The specific role of QSEIs in their catalytic behavior is justified via comparison between spin-polarized and non-spin-polarized calculations

Phase Space Methods in Image Formation Theory

A review of the basic mathematical principles and properties of some phase space functions (Wigner and Ambiguity functions) is first presented in a more general mathematical context. Then, we deal in detail with three applications : image formation in optical systems (specifically cascading systems of lenses), image formation in Transmission Electron Microscopy, by taking advantage of some formal similarities with the previous examples and, finally, contrast transfer functions in Electron Microscopy in order to obtain 2-dimensional plots which provide information on the behavior of a transmission electron microscope. Also, the relations of these functions with other mathematical tools utilized in image processing and image formation theory are discussed

“Voz e pinho”: recursos utilizados por Lula Galvão em duas gravações na formação de voz e violão

Este artigo apresenta um recorte da dissertação intitulada O Violão e a Guitarra de Lula Galvão: um estudo sobre sua atuação musical em diferentes formações instrumentais e tem como foco específico a atuação de Lula Galvão enquanto instrumentista companhador n contexto de duos de voz e violão. Para tanto, foram analisados os principais recursos técnicos e estilísticos empregados pelo músico em duas faixas: Luas de Subúrbio, de autoria de Guinga e Aldir Blanc e interpretada por Leila Pinheiro no álbum Catavento e Girassol (1996); Folha Morta, composta por Ary Barroso e cantada por Rosa Passos no CD Letra e Música – Ary Barroso (1997). A fim de embasar teoricamente as análises e discussões, foram empregados trabalhos de Arnold Schoenberg, Philip Tagg e Sérgio Freitas

The thiocyanate anion as a polydentate halogen bond acceptor

International audienceCo-crystallisation of the Et4N+ or n-Bu4N+ salts of the thiocyanate anion with o-, m- and p-diodoperfluorobenzene or the sym-trifluorotriiodobenzene allowed for the isolation of six different salts which were structurally characterized by single crystal X-ray diffraction. Halogen bonding interactions are observed between the neutral iodinated molecules acting as halogen bond donors and the S or N ends of the thiocyanate anion, with a variety of bonding modes (terminal as well as bridging), and characterised by short I(N,S) contacts and linear C-I(N,S) motifs. On the other hand, the IN≡C angles present deviations from linearity (145-170°) while the IS-C angles are close to 90°, revealing a type II halogen bond interaction with the S atom acting as pseudo halogen. The observation of structures where only the S or the N atom are engaged in halogen bonding suggests that the two coordination modes are close in energy, as confirmed by DFT calculations and ELF analysis which give also a rationale for the observed structural preferences. This bidentate nature of the SCN− anion in halogen bonding interactions is reminiscent of its various coordination modes with the Cd2+ cation, best understood in terms of the hard-soft acid-base concept

The guitar style of Lula Galvão : a study on his musical performance in different instrumentations

Orientador: Hermilson Garcia do NascimentoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ArtesResumo: O presente trabalho se propôs a estudar a performance musical de Lula Galvão em diferentes formações instrumentais, com foco em três frentes de sua atuação: i. acompanhador; ii. improvisador; iii. solista (violão solo). Para tanto, foram selecionados fonogramas para a análise que compreendeu contextos musicais distintos: formações que vão desde violão solo até septeto e o emprego tanto da guitarra elétrica quanto do violão. Outro critério adotado para seleção das obras foi abranger gêneros musicais variados, a saber: i. baladas jazzísticas ii. bolero; iii. bossa/samba; iv. choros. A principal ferramenta metodológica utilizada foi um procedimento analítico de comparação entre objetos, assemelhado ao uso no modelo proposto por Philip Tagg em seu trabalho intitulado Analisando a Música Popular: Teoria, Método e Prática (2003). A escolha por tal referencial justificou-se pela busca por uma análise que almejasse interlocução com exemplos musicais cronologicamente anteriores (significativos para o estudo do caso) e que não fosse apenas descritiva (em termos técnico-musicais). A pesquisa também contou com contextualizações de cunho teórico/prático, com destaque para observação de uma possível vertente ou linha estética que se encontra dentro do grande universo intitulado "violão popular brasileiro" e que dialoga com a guitarra jazzística, na qual se incluem músicos como Lula Galvão, Hélio Delmiro e Romero Lubambo. Os resultados das análises musicais apontam para o uso de recursos recorrentes em performances do músico, de maneira que foi possível, por meio da metodologia proposta, estabelecer relação direta entre as práticas de Galvão e de instrumentistas referenciais para sua formação musical através do reconhecimento e comparação de determinados procedimentos técnicos. O estilo de Lula Galvão se baseia em uma síntese de recursos estilísticos referentes a contextos musicais distintos, tais como: i. a influência técnica-instrumental da "escola" de violão erudito; ii. a presença de procedimentos associados ao jazz, refletida em sua atuação pela sua própria escuta de músicos desse campo ¿ que inclui nesse caso, em grande medida, o guitarrista Hélio Delmiro ¿ e pelo estudo de materiais didáticos provenientes da metodologia de ensino jazzística (jazz theory); iii. o emprego de elementos associados ao campo da música popular brasileira (área de maior atuação e predileção do instrumentista), a exemplo de recursos rítmicos que remetem a importantes violonistas brasileiros; o uso predominante do violão em relação à guitarra, sobretudo em práticas de gêneros brasileiros. O diferencial desse trabalho se encontra no fato de ele reunir características distintas de um músico considerado uma referência, o que torna a pesquisa pioneira em relação a uma análise ampla das atividades musicais de Lula GalvãoAbstract: The present work had the proposition to study the musical performance of Lula Galvão at different instrumental situations, focusing on three fronts of his actuation: i. accompanist; ii. improviser; iii. solo player (guitar solo). In order to do so, phonograms were selected for the analysis which comprehended distinct musical contexts: situations going from solo guitar to a septet and the use of both electric guitar and acoustic guitar. Another criteria for opus selection was the aim to comprehend various musical genres, such as: i. bolero; ii. jazz ballads; iii. bossa/samba; iv. choros. The main methodological tool used was an analytical procedure of comparation between objects, akin to the proposed model used by Philip Tagg in his work named Analysing Popular Music: Theory, Method and Practice (2003). The use of such referential was justified by the intent towards an analysis that aimed interlocution with chronologically previous musical examples (relevant to the study of the case) and which wasn¿t only descriptive (in technical-musical terms). The research was also supported by theoretical and practical contextualizations, highlighting the observation of a possible strand or esthetic line which is within the big universe named "popular Brazilian guitar" and dialogues with the aesthetics of jazz guitar. In this group are included musicians such as Lula Galvão, Hélio Delmiro and Romero Lubambo. The musical analysis results point towards the use of recurrent resources used by the musician in performances, making it possible, through the proposed methodology, to stablish a direct relation between Galvão¿s practices and those from musicians who were referential to his musical formation through the recognition and comparison of certain technical procedures. Lula Galvão¿s style is based on a synthesis of stylistic resources referring to different musical contexts, such as: i. the technical-instrumental influence from the classic guitar "school"; ii. the presence of procedures associated with jazz, reflected in his performance by his appreciation of musicians from this field ¿ including in this case, by a large margin, the guitar player Hélio Delmiro ¿ and by the study of didactic materials from the jazz teaching methodology (jazz theory); iii. the use of elements associated with the field of Brazilian popular music (the musician's favorite and most prolific actuation area), such as: rhythmic resources alluding to important Brazilian guitar players; the preponderant use of the acoustic guitar rather than the electric guitar, even more so in Brazilian genres practices. This work¿s differential is in the fact that it congregates distinct characteristics from a referential musician, which makes it a pioneer research in relation to a broad analysis of the musical activities of Lula GalvãoMestradoMúsica, Teoria, Criação e PráticaCAPE

Nivel de adherencia a tratamientos farmacológicos antihipertensivos y su relación con el control de los niveles de presión arterial en un grupo de pacientes diagnosticados con hipertensión arterial en la Institución Prestadora de Servicios de Salud

Globally, chronic, non-transmissible diseases have beome a constant concern for the health authorities all over the world. They have become the primary casuses of death in the world, for example, everday more people suffer, have complications and die from hyperstension. Antihypertension therapy is vital to treating hypertension, but globally only 51% of diagnosed patients adhere to treatment. In cases of patients diagnosed with hypertesion by the Institute of Health Services the levels of controlled blood pressure are low and could reflect the global situation. The importance of the present work is to know the real situation of the patients and to know the real levels of adherence to antihypertension drug treatments and correlate the levels of blood pressure control.A nivel mundial las enfermedades crónicas no transmisibles se han convertido en una preocupación constante para las autoridades de salud de todos los países, las mismas que se han posicionado como las primeras causantes de la mortalidad de los ciudadanos del mundo; La Hipertensión Arterial, reviste una particular problemática, ya que día a día en el mundo encontramos un crecimiento significativo en el número de personas que la padecen, se complican y mueren. Reviste vital importancia la adherencia terapéutica a los tratamientos antihipertensivos ya que se estima que aproximadamente solo el 51% de los pacientes diagnosticados con Hipertensión Arterial logra adherirse al tratamiento suministrado. Para el caso de los pacientes diagnosticados con HTA en la Institución Prestadora de Servicios de Salud (I.P.S Mallamas), los niveles de control de cifras de presión arterial encontrados son bajos y pueden estar reflejando la situación global de la problemática, por lo tanto la importancia del presente trabajo es conocer la realidad de los pacientes enfocando la investigación a saber cuál es el nivel de adherencia a los tratamientos farmacológicos antihipertensivos, y conocer el nivel de control de esas cifras tensionales

Riboflavin kinase and pyridoxine 5'-phosphate oxidase complex formation envisages transient interactions for FMN cofactor delivery

Enzymes catalysing sequential reactions have developed different mechanisms to control the transport and flux of reactants and intermediates along metabolic pathways, which usually involve direct transfer of metabolites from an enzyme to the next one in a cascade reaction. Despite the fact that metabolite or substrate channelling has been widely studied for reactant molecules, such information is seldom available for cofactors in general, and for flavins in particular. Flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) act as cofactors in flavoproteins and flavoenzymes involved in a wide range of physiologically relevant processes in all type of organisms. Homo sapiens riboflavin kinase (RFK) catalyses the biosynthesis of the flavin mononucleotide cofactor, and might directly interplay with its flavin client apo-proteins prior to the cofactor transfer. Non-etheless, none of such complexes has been characterized at molecular or atomic level so far. Here, we particularly evaluate the interaction of riboflavin kinase with one of its potential FMN clients, pyridoxine-5′-phosphate oxidase (PNPOx). The interaction capacity of both proteins is assessed by using isothermal titration calorimetry, a methodology that allows to determine dissociation constants for interaction in the micromolar range (in agreement with the expected transient nature of the interaction). Moreover, we show that; i) both proteins become thermally stabilized upon mutual interaction, ii) the tightly bound FMN product can be transferred from RFK to the apo-form of PNPOx producing an efficient enzyme, and iii) the presence of the apo-form of PNPOx slightly enhances RFK catalytic efficiency. Finally, we also show a computational study to predict likely RFK-PNPOx binding modes that can envisage coupling between the FMN binding cavities of both proteins for the potential transfer of FMN

Collective Action and Social Innovation in the Energy Sector: A Mobilization Model Perspective

This conceptual paper applies a mobilization model to Collective Action Initiatives (CAIs) in the energy sector. The goal is to synthesize aspects of sustainable transition theories with social movement theory to gain insights into how CAIs mobilize to bring about niche-regime change in the context of the sustainable energy transition. First, we demonstrate how energy communities, as a representation of CAIs, relate to social innovation. We then discuss how CAIs in the energy sector are understood within both sustainability transition theory and institutional dynamics theory. While these theories are adept at describing the role energy CAIs have in the energy transition, they do not yet offer much insight concerning the underlying social dimensions for the formation and upscaling of energy CAIs. Therefore, we adapt and apply a mobilization model to gain insight into the dimensions of mobilization and upscaling of CAIs in the energy sector. By doing so we show that the expanding role of CAIs in the energy sector is a function of their power acquisition through mobilization processes. We conclude with a look at future opportunities and challenges of CAIs in the energy transition.This research was conducted under the COMETS (Collective action Models for Energy Transition and Social Innovation) project, funded by the Horizon 2020 Framework Program of the European Commission, grant number 837722

Capital de trabajo y su incidencia en la rentabilidad de la ferretería San Gregorio, Chepén, 2021

La presente investigación titulada, “Capital de trabajo y su incidencia en la rentabilidad de la ferretería San Gregorio, Chepén, 2021 “establece como objetivo general , Determinar la relación entre el capital de trabajo y la rentabilidad de la ferretería San Gregorio, Chepén, 2021, a la metodología, la investigación es de tipo aplicada y de diseño no experimental -correlacional, en el que se tomó como muestra a 32 colaboradores y sus estados financieros , utilizándose como instrumento la ficha de la investigación a través del cuestionario, donde se dividió en 6 preguntas para la primera variable denominada capital de trabajo y 6 preguntas para la segunda variable rentabilidad, los cuales sirvieron de instrumento para la obtención de información, el cual fue llevado a las pruebas estadísticas teniendo como resultado de acuerdo a la prueba de Roe Spearman un coeficiente de 0,555 donde se demuestra que se tiene una correlación moderada, consiguientemente, se concluye que si existe relación entre el capital de trabajo y la rentabilidad

Rhodium-NHC-Catalyzed gem-Specific O-Selective Hydropyridonation of Terminal Alkynes

The dinuclear complex Rh(mu-Cl)(eta(2)-coe)(IPr)](2) is an efficient catalyst for the O-selective Markovnikov-type addition of 2-pyridones to terminal alkynes. DFT calculations support a hydride-free pathway entailing intramolecular oxidative protonation of a pi-alkyne by a kappa N-1-hydroxypyridine ligand. Subsequent O-nucleophilic attack on a metallacyclopropene species affords an O-alkenyl-2-oxypyridine chelate rhodium intermediate as the catalyst resting state. The release of the alkenyl ether is calculated as the rate-determining step