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A DESCOBERTA DOS RAIOS X

, 2017
O dia 8 de novembro de 1895 foi transcendente para a ciência e, principalmente, para a medicina. Wilhelm C. Roentgen, professor de Física da Universidade de Wurzburg, na Alemanha, fez uma das descobertas mais importantes da história das ciências: o achado de misteriosos raios, na época desconhecidos, que permitiam olhar dentro do corpo.
SILVA, HORÁCIO SCIGLIANO DA
core   +3 more sources

Avanços em caracterização de amostras sólidas cristalinas através de Difratometria de Raios-X

Estação Científica, 2013
Neste artigo realiza-se uma revisão sobre os fundamentos da técnica de difratometria de raios X, bem como sua utilização nas empresas, universidades, indústrias e centros de pesquisa, como sendo uma das mais difundidas e importantes técnicas de ...
Henrique Duarte da Fonseca Filho, Gerson Anderson de Carvalho Lopes   +1 more
doaj   +1 more source

Lattice Stiffening and Delayed Fluorescence in Columnar Liquid-Crystalline Glasses. [PDF]

Chempluschem
If the substitution pattern is well‐chosen, semiflexible triaryltriazine esters form glassy columnar liquid crystals whose column lattice distinctively shrinks at the glass transition. The presence of columnar liquid‐crystalline order is found to favor delayed fluorescence by triplet–triplet annihilation.
da Silva Kutz M, de Oliveira WA, Belarmino Cabral MG, Durola F, Bechtold IH, Westphal E, Bock H.   +6 more
europepmc   +2 more sources

Mechanistic Insights and Catalytic Efficiency of a 2,2'-Bipyridine-Coordinated Peroxidovanadium Complex as a Haloperoxidase Biomimetic. [PDF]

Chempluschem
A peroxidovanadium(V) complex mimics vanadium haloperoxidases for eco‐friendly halogenation of organic substrates. Density functional theory studies reveal two major reaction pathways for iodide/bromide oxidation. The catalyst offers high‐yield bromination/iodination of 8‐hydroxyquinoline (73/86%) under mild conditions (30 °C, pH 5.8), and it also ...
Fachini LG, Elisandro EVS, Baptistella GB, Bottini RCR, Briganti M, Nunes GG, de Sá EL.   +6 more
europepmc   +2 more sources

Reappraisal is less effective than distraction in downregulation of neural responses to physical threats—An event‐related potential investigation

Psychophysiology, Volume 60, Issue 9, September 2023., 2023
Abstract Evolutionary threats (ETs), such as predatory animals and heights, elicit stronger fear responses and are more often the subject of specific phobias, as compared to modern threats (MTs, such as guns and motorcycles). Since processing of ET depends on lower‐order, phylogenetically conserved neural fear circuits, it may be less susceptible to ...
Agnieszka K. Adamczyk, Miroslaw Wyczesany, Karin Roelofs, Jacobien M. van Peer   +3 more
wiley   +1 more source

Anxiety attenuates learning advantages conferred by statistical stability and induces loss of volatility‐attuning in brain activity

Human Brain Mapping, Volume 44, Issue 6, Page 2557-2571, April 15, 2023., 2023
To determine how anxious individuals learn during stable and volatile environments, we used an auditory oddball reversal paradigm combined with threat‐of‐shock during fMRI scanning. We found that threat eliminates the behavioural learning advantages of stable over volatile environments.
Elise G. Rowe, Clare D. Harris, Ilvana Dzafic, Marta I. Garrido   +3 more
wiley   +1 more source

Acute stress alters probabilistic reversal learning in healthy male adults

European Journal of Neuroscience, Volume 57, Issue 5, Page 824-839, March 2023., 2023
In this study, we investigated the effect of acute psychosocial stress on flexible behavioural adaptation using a reversal learning task during fMRI scanning and after a Trier Social Stress Test in 28 healthy male participants. We found a small improving effect on task performance accuracy, which was best explained by Rescorla–Wagner double updating in
Lara Wieland, Claudia Ebrahimi, Teresa Katthagen, Martin Panitz, Lennart Luettgau, Andreas Heinz, Florian Schlagenhauf, Zsuzsika Sjoerds   +7 more
wiley   +1 more source

Measurements of Atmospheric X and Gamma Rays-Balloon Experiments at Subantarctic Region

Brazilian Journal of Geophysics, 1986
The results of the stratospheric balloon experiments conducted to measure the atmospheric X and gamma rays are presented. These experiments, conducted at Comandante Ferraz base in sub antarctic region have provided the spectrum of ground ...
Jayanthi UB., R.V. Corrêa, F.G. Blanco
doaj   +1 more source

Forest disturbance and growth processes are reflected in the geographical distribution of large canopy gaps across the Brazilian Amazon

Journal of Ecology, Volume 110, Issue 12, Page 2971-2983, December 2022., 2022
The proportion of large gaps in the forest canopy varied substantially over the Brazilian Amazon. We have shown that the trends can be explained by geographical variation in disturbance and growth. The frequency of extreme weather events is predicted to increase under climate change, and changes could lead to greater forest disturbance, which should be
Cristiano Rodrigues Reis, Toby D. Jackson, Eric Bastos Gorgens, Ricardo Dalagnol, Tommaso Jucker, Matheus Henrique Nunes, Jean Pierre Ometto, Luiz E. O. C. Aragão, Luiz Carlos Estraviz Rodriguez, David A. Coomes   +9 more
wiley   +1 more source

Dos raios X às imagens dos átomos nos cristais

Revista Brasileira de História da Ciência, 2023
Quando descobertos por Wilhelm Conrad Röntgen (1845-1923), os raios X causaram fascínio e grandes debates entre as pessoas no final do século XIX e início do XX. O estudo das propriedades desse novo tipo de radiação levou ao entendimento da estrutura da
Leonardo Lessa Pacheco , Ivoni Freitas-Reis   +1 more
doaj   +1 more source