28 research outputs found
CASSCF and MR–CISD study of the n−4s and n−4pe Rydberg states of the CF3Cl
AbstractThe low-lying n−4s (S2 and T2) and n−4pe (S3 and T3) Rydberg states of the CF3Cl have been studied at the CASSCF, MR–CISD, MR–CISD+Q and MR–AQCC levels using the mixed aug–cc–pVDZ/d–aug–cc–pVDZ and aug′–cc–pVTZ/d′–aug′–cc–pVTZ basis sets. Spin–orbit corrections for the singlet energies, vertical excitation energies and oscillator strengths have been computed. The effect of the inclusion of K+L or only the K inner shell chlorine orbitals in the frozen core space at the post-CASSCF levels has also been discussed. Good agreement with available experimental and with previous high-level theoretical results has been achieved
PERCEPÇÕES SOBRE A COMPETÊNCIA SOCIOAFETIVA DE CORDIALIDADE E A HUMANIZAÇÃO DA TUTORIA A DISTÂNCIA
As percepções de tutores a distância sobre a cordialidade e a humanização de suas práticas pedagógicas foram perquiridas. Doze tutores de uma instituição privada de Ensino Superior do Estado do Rio de Janeiro participaram da pesquisa. Para sete (58%) deles, a cordialidade seria a principal competência socioafetiva a se exigir de um tutor a distância. Foram identificadas diversas situações nas quais seria imprescindível ser cordial, como quando um aluno manifesta desestímulo ou dificuldade de aprendizagem. Todos enfatizaram a necessidade de uma postura cortês na abertura de cada nova etapa de disciplina ou curso. Entretanto, apenas cinco (42%) reputaram-na indispensável no acolhimento de alunos. Para oito (67%) tutores, a identificação nominal dos cursistas e, para seis (50%), o uso de frases motivadoras seriam formas cotidianas de exercício da cordialidade. Palavras chave: Competência socioafetiva. Cordialidade, Tutoria a distância
Competencia en información: un abordaje desde el archivista
Objetivo. Analisa possíveis conexões entre a competência em informação, o arquivista e o arquivo. As atribuições do arquivista foram estudadas, a fim de identificar quais os vínculos com a competência em informação, tendo como base o que se apresenta na bibliografia arquivística e de competência em informação.Método. A pesquisa tem por finalidade ser básica, está caracterizada em relação ao objetivo como exploratória, apresenta abordagem qualitativa, e utiliza a técnica bibliográfica.Resultados. Os resultados apresentam a competência dos profissionais da informação, definem a competência em informação, tratam da competência em informação do arquivista e da dimensão política evidenciada na relação arquivista e arquivo. Conclui que o arquivista é um profissional competente em informação e suas atribuições intensificam essa competência. Com relação ao arquivo, esse ambiente auxilia no desenvolvimento da dimensão política da competência em informação do arquivista, já que permite o acesso às informações documentais e o exercício da cidadania.Objective. It analyzes possible connections between information literacy, the archivist and the archive. The assignments of the archivist were studied in order to identify the links with information literacy, based on what is presented in the archives administration bibliography and information literacy.Method. The research aims to be basic, is characterized in relation to the objective as exploratory, presents a qualitative approach, and uses the bibliographic technique.Results. The results present the competence of the information professionals, define the information literacy, the competence in information of the archivist and the political dimension in the relation archivist and archive. It concludes that the archivist is a competent information professional and his assignments intensify this competence. Regarding the archive, this environment assists in the development of the political dimension of the information literacy of the archivist, since it allows access to documentary information and the exercise of citizenship.Objetivo. Analiza las posibles conexiones entre la competencia en información, el archivista y el archivo. Las atribuciones del archivista fueron estudiadas, a fin de identificar cuáles son los vínculos con la competencia en información, teniendo como base lo que se presenta en la bibliografía archivística y de competencia en información.Método. Es una investigación exploratoria, presenta un abordaje cualitativo, y usa la técnica de revisión bibliográfica.Resultados. Se presenta la competencia de los profesionales de la información, se define la competencia en información, se aborda la competencia en información del archivista y de la dimensión política evidenciada en la relación archivista y archivo. Concluye que el archivista es un profesional competente en información y sus atribuciones intensifican esa competencia. Con relación al archivo, ese ambiente apoya en el desarrollo de la dimensión política de la competencia en información del archivista, ya que permite el acceso a la información documental y el ejercicio de la ciudadanía
Real-world effectiveness and safety of direct-acting antivirals for the treatment of hepatitis C virus in kidney and liver transplant recipients: experience of a large transplant center in Brazil
Direct-acting antivirals are the gold-standard treatment for chronic HCV infections, but few studies have investigated their use on kidney and liver transplant recipients. We conducted a real-world study to evaluate the rates of sustained virological response with direct-acting antivirals in kidney and liver transplant recipients. Moreover, it also aimed to evaluate direct-acting antivirals (DAAs) interference with immunosuppressant levels and to describe the frequency of adverse events. As part of this retrospective observational cohort, we included adult patients that had undergone a kidney transplant (KT) or liver transplant (LT) at our center, had a chronic HCV infection, and were treated with DAAs from June 2016 to December 2021. A total of 165 patients were included in the analysis, divided in 108 KT and 57 LT recipients. HCV genotype 1 was more frequent in KT (58.4%), and genotype 3 was more prevalent in LT (57.9%) patients. Sustained virological response was achieved in 89.6% of patients. Adverse effects were reported by 36% of patients. There were significant interactions with immunosuppressants requiring dose adjustments. A total of three episodes of rejection were reported in KT recipients. In conclusion, DAA treatment resulted in high rates of SVR and was well tolerated in both kidney and liver transplant patients. Adverse events were frequent but not severe in most patients, with low treatment drop-out rates. Interactions with immunosuppressants need monitoring since dose adjustments may be required. Reporting real-life experiences is important to help build evidence for patient management in non-controlled environments
Photoinduced Formation of H-bonded Ion Pair in HCFC-133a
International audienceHigh-level multireference electronic structure calculations have been performed to study the Cl − yield from photoexcited CF3CH2Cl (HCFC-133a). The analysis of this process tells that it relates to an electron transfer from the carbon to the Cl atom, forming a highly polar contact ion-pair complex, CF3HCH + •••Cl − , in the excited (S3) state. This complex has a strong binding energy of 3.53 eV, from which 0.47 eV is due to an underlying hydrogen bond. Through comparison with the results obtained for the prototype CH3Cl system, where a similar ion-pair state associated with Cl − formation has also been observed, it is suggested that photodissociation of HCFC-133a can also yield Cl − through analogous process. This hypothesis is further supported by nonadiabatic dynamics simulations, which shows formation of the ion-pair complex in the sub-picosecond time scale.
The generality of the GUGA MRCI approach in COLUMBUS for treating complex quantum chemistry
The core part of the program system COLUMBUS allows highly efficient calculations using variational multireference (MR) methods in the framework of configuration interaction with single and double excitations (MR-CISD) and averaged quadratic coupled-cluster calculations (MR-AQCC), based on uncontracted sets of configurations and the graphical unitary group approach (GUGA). The availability of analytic MR-CISD and MR-AQCC energy gradients and analytic nonadiabatic couplings for MR-CISD enables exciting applications including, e.g., investigations of π-conjugated biradicaloid compounds, calculations of multitudes of excited states, development of diabatization procedures, and furnishing the electronic structure information for on-the-fly surface nonadiabatic dynamics. With fully variational uncontracted spin-orbit MRCI, COLUMBUS provides a unique possibility of performing high-level calculations on compounds containing heavy atoms up to lanthanides and actinides. Crucial for carrying out all of these calculations effectively is the availability of an efficient parallel code for the CI step. Configuration spaces of several billion in size now can be treated quite routinely on standard parallel computer clusters. Emerging developments in COLUMBUS, including the all configuration mean energy multiconfiguration self-consistent field method and the graphically contracted function method, promise to allow practically unlimited configuration space dimensions. Spin density based on the GUGA approach, analytic spin-orbit energy gradients, possibilities for local electron correlation MR calculations, development of general interfaces for nonadiabatic dynamics, and MRCI linear vibronic coupling models conclude this overview
A importância do método de Hartree no ensino de química quântica
Hartree's original ideas are described. Its connection with electrostatics can be explored in order to decrease the gap between teaching of Physics and Chemistry. As a consequence of its simplicity and connection with electrostatics, it is suggested that Hartree's method should be presented before the Hartree-Fock method. Besides, since the fundamental concepts of indistinguishibility of electrons along with the antissimetry of the wave function are missing in the Hartree's product, the method itself can be used to introduce these concepts. Despite the fact that these features are not included in the trial wavefunction, important qualitatively correct results can be obtained
Competência em informação: uma abordagem sobre o arquivista
Objective. It analyzes possible connections between information literacy, the archivist and the archive. The assignments of the archivist were studied in order to identify the links with information literacy, based on what is presented in the archives administration bibliography and information literacy.Method. The research aims to be basic, is characterized in relation to the objective as exploratory, presents a qualitative approach, and uses the bibliographic technique.Results. The results present the competence of the information professionals, define the information literacy, the competence in information of the archivist and the political dimension in the relation archivist and archive. It concludes that the archivist is a competent information professional and his assignments intensify this competence. Regarding the archive, this environment assists in the development of the political dimension of the information literacy of the archivist, since it allows access to documentary information and the exercise of citizenship.Objetivo. Analisa possíveis conexões entre a competência em informação, o arquivista e o arquivo. As atribuições do arquivista foram estudadas, a fim de identificar quais os vínculos com a competência em informação, tendo como base o que se apresenta na bibliografia arquivística e de competência em informação.Método. A pesquisa tem por finalidade ser básica, está caracterizada em relação ao objetivo como exploratória, apresenta abordagem qualitativa, e utiliza a técnica bibliográfica.Resultados. Os resultados apresentam a competência dos profissionais da informação, definem a competência em informação, tratam da competência em informação do arquivista e da dimensão política evidenciada na relação arquivista e arquivo. Conclui que o arquivista é um profissional competente em informação e suas atribuições intensificam essa competência. Com relação ao arquivo, esse ambiente auxilia no desenvolvimento da dimensão política da competência em informação do arquivista, já que permite o acesso às informações documentais e o exercício da cidadania.Objetivo. Analiza las posibles conexiones entre la competencia en información, el archivista y el archivo. Las atribuciones del archivista fueron estudiadas, a fin de identificar cuáles son los vínculos con la competencia en información, teniendo como base lo que se presenta en la bibliografía archivística y de competencia en información.Método. Es una investigación exploratoria, presenta un abordaje cualitativo, y usa la técnica de revisión bibliográfica.Resultados. Se presenta la competencia de los profesionales de la información, se define la competencia en información, se aborda la competencia en información del archivista y de la dimensión política evidenciada en la relación archivista y archivo. Concluye que el archivista es un profesional competente en información y sus atribuciones intensifican esa competencia. Con relación al archivo, ese ambiente apoya en el desarrollo de la dimensión política de la competencia en información del archivista, ya que permite el acceso a la información documental y el ejercicio de la ciudadanía
Cope Rearrangement of 1,5-Hexadiene: Full Geometry Optimizations Using Analytic MR-CISD and MR-AQCC Gradient Methods
Determination of Energy Minima and Saddle Points Using Multireference Configuration Interaction Methods in Combination with Reduced Gradient Following: The S 0 Surface of H 2 CO and the T 1 and T 2 Surfaces of Acetylene
Abstract: The implementation of the reduced gradient following (RGF) method into the COLUMBUS quantumchemical program system is reported using the newly developed analytic MR-CISD/AQCC gradient feature. By this combination a very useful tool has been developed for general searches of stationary points on ground-and excited-state energy surfaces. This procedure is applied to the S 0 surface of H 2 CO and the T 1 and T 2 surfaces of acetylene. For H 2 CO we investigated three minima (formaldehyde, s-trans, and s-cis hydroxycarbene) and five saddle points. For the T 1 and T 2 states of acetylene the cis-and trans-minima and the planar and nonplanar saddle points were computed