607 research outputs found
A ambientalização curricular e a formação inicial de professores de química: um estudo de caso brasileiro
O principal objetivo deste trabalho refere-se à investigação do modo como a dimensão ambiental se insere na formação dos estudantes do curso de licenciatura em Química de uma universidade pública brasileira. A temática da pesquisa revela-se importante, pois há a preocupação institucional com a proposta de ambientalização curricular na formação de profissionais, neste caso, professores de Química, que se comprometam continuamente com o estabelecimento das melhores relações possíveis entre sociedade e natureza, contemplando valores e princípios éticos universalmente reconhecidos. Além disto, pretende-se pesquisar a forma como esta dimensão se relaciona com as temáticas científica, tecnológica, econômica e social, tal como se pode observar na proposta concernente ao perfil profissional e habilidades a serem desenvolvidas do licenciando do referido curso
Observation of interference between two distinct autoionizing states in dissociative photoionization of H 2
Dissociative photoionization (DPI) of randomly oriented H2 molecules has been studied using linearly polarized synchrotron radiation at selected photon energies of 31, 33, and 35 eV. Large amplitude oscillations in the photoelectron asymmetry parameter β, as a function of electron energy, have been observed. The phase of these β oscillations are in excellent agreement with the results of recent close coupling calculations [Fernández and Martín, New J. Phys. 11, 043020 (2009)]. We show that the oscillations are the signature of interferences between the 1Q1 Σu+1 and 1Q2 Πu1 doubly excited states decaying at different internuclear distances. The oscillations thus provide information about the classical paths followed by the nuclei. The presence of such oscillations is predicted to be a general phenomenon in DPIWe acknowledge NSERC, CLS, and UoW for their support. We thank Mare Nostrum BSC and CCC-UAM for allocation of computer time. Work partially supported by the MICINN Projects No. FIS2010-15127, No. ACI2008-0777, and No. CSD 2007-00010, the European MC-ITN CORINF, and the COST Action CM070
PADC Detected External Neutron Field by Nuclear Tracks at RFX-mod
Measured neutron signals relevant for plasma diagnostics on Reversed Field pinch eXperiment, RFX-mod, are obtained by nuclear track methodology with PADC-NtD’s. this technique provides the external neutron field values around the RFX-mod installation during pulsed operation. Charged particles from (n, p) and (n, α) reactions are related to formed latent tracks. these are etched in a thermoregulated water bath with a 6.25M, KOh solution at 60oC. Observed tracks were analyzed to determine track density from which neutron fluence spatial values should be derived. Results indicate that the neutron density in the surrounding environment change at most 40%. the epithermal component is 60% higher than that corresponding to the thermal region. the estimated neutron fluence for the whole experiment is 7.5×1010 neutrons cm2/s
Paraoxonase-1 (PON-1) Arylesterase Activity Levels in Patients with Coronary Artery Disease: A Meta-Analysis
Aim: To review and compare the PON-1 arylesterase activity between coronary artery disease (CAD) and non-CAD patients. Methods: Data were obtained by searching MEDLINE and Scopus for all investigations published between January 1, 2000 and March 1, 2021 comparing PON-1 arylesterase activity between CAD and controls. Results: Twenty studies, based on 5417 patients, met the inclusion criteria and were included in the analysis. A random effect model revealed that PON-1 arylesterase activity was significantly lower in the CAD group compared to controls (SMD = -0.587, 95%CI = -0.776 to -0.339, p < 0.0001, I2 = 92.3%). In CAD patients, the PON-1 arylesterase activity was significantly higher among CAD patients without diabetes mellitus (DM) compared to those with diabetes (SMD: 0.235, 95% CI: 0.014 to 0.456, p = 0.03, I2 = 0%). Conclusions: PON-1 activity is significantly lower in CAD patients, and those without DM presented a significantly higher PON-1 arylesterase activity
On the electronic structure of methyl butyrate and methyl valerate
No. 2019-A0010806820
UIDB/00068/2020
PTDC/FIS-AQM/31281/2017Abstract: We present novel results of the analysis of the electronic structure of two aliphatic esters: methyl butyrate and methyl valerate. High-resolution photoabsorption spectra were collected and analyzed over the energy range 4.0–10.8 eV and showed for both the molecules not only a clear band of the HOMO to LUMO transition, but also vibronic structure associated with the first Rydberg-valence transition. Photoelectron spectra recorded from 9 to over 28 eV revealed many ionization states with the first adiabatic ionization energies found to be 9.977 eV and 9.959 eV for methyl butyrate and methyl valerate, respectively. Ab initio calculations have been performed in order to help assign the photoabsorption and photoelectron features. Photolysis life times in the atmosphere were calculated revealing that photolysis is not competitive over hydroxyl radical scavenging in the process of removal of these esters from the atmosphere. Graphical abstract: [Figure not available: see fulltext.]publishersversionpublishe
Classical diamagnetism, magnetic interaction energies, and repulsive forces in magnetized plasmas
The Bohr-van Leeuwen theorem is often summarized as saying that there is no
classical magnetic susceptibility, in particular no diamagnetism. This is
seriously misleading. The theorem assumes position dependent interactions but
this is not required by classical physics. Since the work of Darwin in 1920 it
has been known that the magnetism due to classical charged point particles can
only be described by allowing velocity dependent interactions in the
Lagrangian. Legendre transformation to an approximate Hamiltonian can give an
estimate of the Darwin diamagnetism for a system of charged point particles.
Comparison with experiment, however, requires knowledge of the number of
classically behaving electrons in the sample. A new repulsive effective
many-body force, which should be relevant in plasmas, is predicted by the
Hamiltonian.Comment: added references, revise
A FORMAÇÃO NO TEMPO E NO ESPAÇO DA INTERNET DAS COISAS
RESUMO: A Internet das Coisas tem revolucionado a forma de produção e reprodução do conhecimento. Trata-se de um tipo de interface comunicacional entre humanos, máquinas e objetos que, ao fundir os mundos material e informacional, suscita as seguintes questões: (1) a possibilidade de obtenção imediata de quaisquer informações implicaria na produção do pensamento crítico, em uma espécie de relação causa-efeito?; (2) se é possível acessar as informações em quaisquer tempo e espaço, quais seriam as transformações decorrentes no processo formativo dos alunos e dos professores? Justamente essas questões motivaram os autores do artigo a elaborar o seguinte objetivo: refletir criticamente sobre a revitalização do conceito de formação (Bildung ) na temporalidade e localidade da Internet das Coisas
- …