272 research outputs found
(2,2′-Bipyridine-κ2 N,N′){N-[(2-oxidonaphthalen-1-yl-κO)methylidene]-l-valinato-κO}copper(II) trihydrate
In the title complex, [Cu(C16H15NO3)(C10H8N2)]·3H2O, the CuII atom is five coordinated by O,N,O′-donor atoms of the Schiff base ligand and by two N atoms of the 2,2′-bipyridine ligand in a distorted square-pyramidal geometry. In the crystal, molecules are linked into a two-dimensional network parallel to (011) by O—H⋯O hydrogen bonds
Acoustic diagnostics of femtosecond laser filamentation
The promising application of femtosecond laser filamentation in atmospheric
remote sensing brings imperative demand for diagnosing the spatiotemporal
dynamics of filamentation. Acoustic emission (AE) during filamentation opens a
door to give the insight into the dynamic evolution of filaments in air. In
particular, the frequency features of the acoustic emission provide relevant
information on the conversion of laser energy to acoustic energy. Here, the
acoustic emission of femtosecond laser filament manipulated by energy and the
focal lengths was measured quantitatively by a broadband microphone, and the
acoustic parameters were compared and analyzed. Our results showed that the
acoustic power presents a squared dependence on the laser energy and the
bandwidth of the acoustic spectrum showed a significant positive correlation
with laser energy deposition. It was found that the spectrum of the acoustic
pulse emitted from the middle of the filament has a larger bandwidth compared
to those emitted from the ends of the filament and the spectrum of the acoustic
pulse is also an indicator of the filament intensity distribution. These
findings are helpful for studying the plasma filament properties and complex
dynamic processes through acoustic parameters and allow the optimization of
remote applications.Comment: 8 pages,5 figure
Simple graphene chemiresistors as pH sensors: fabrication and characterization
We report the fabrication and characterization of a simple gate-free graphene
device as a pH sensor. The graphene sheets are made by mechanical exfoliation.
Platinum contact electrodes are fabricated with a mask-free process using
focused ion beam, and then expanded by silver paint. Annealing is used to
improve the electrical contact. The experiment on the fabricated graphene
device shows that the resistance of the device decreases linearly with
increasing pH values (in the range of 4-10)in the surrounding liquid
environment. The resolution achieved in our experiments is approximately 0.3 pH
in alkali environment. The sensitivity of the device is calculated as
approximately 2 k\Omega /pH. The simple configuration, miniaturized size and
the integration ability make graphene-based sensors promising candidates for
future micro/nano applications
Pedagogical practices of good nursing, medicine and dentistry professors from the student's perception
The aim of this qualitative study was to analyze, in the light of Shuman's concept of pedagogical content knowledge, the pedagogical practices of good nursing, medicine and dentistry professors from the perception of students of a public university in southern Brazil. The study comprised 16 students who were approached through interviews focused by vignettes and qualitative indicators. Pedagogical content knowledge is observed when good professors share the learning objectives while associating theory and practice, fostering student reasoning using a wide range of strategies responsive to contents and the public; carefully prepare and organize their lessons; and allow to be evaluated. Pedagogical content knowledge is presented as a differential in teaching practice; however, students perceive these practices in few professors, leading to the need for recommending rooms and strategies for training health teaching staff
Neurocomputational mechanisms underlying fear-biased adaptation learning in changing environments
AU Humans: Please confirm that all heading levels are represented correctly are able to adapt to the fast-changing world by estimating : statistical regularities of the environment. Although fear can profoundly impact adaptive behaviors, the computational and neural mechanisms underlying this phenomenon remain elusive. Here, we conducted a behavioral experiment (n = 21) and a functional magnetic resonance imaging experiment (n = 37) with a novel cue-biased adaptation learning task, during which we simultaneously manipulated emotional valence (fearful/neutral expressions of the cue) and environmental volatility (frequent/infrequent reversals of reward probabilities). Across 2 experiments, computational modeling consistently revealed a higher learning rate for the environment with frequent versus infrequent reversals following neutral cues. In contrast, this flexible adjustment was absent in the environment with fearful cues, suggesting a suppressive role of fear in adaptation to environmental volatility. This suppressive effect was underpinned by activity of the ventral striatum, hippocampus, and dorsal anterior cingulate cortex (dACC) as well as increased functional connectivity between the dACC and temporal-parietal junction (TPJ) for fear with environmental volatility. Dynamic causal modeling identified that the driving effect was located in the TPJ and was associated with dACC activation, suggesting that the suppression of fear on adaptive behaviors occurs at the early stage of bottom-up processing. These findings provide a neuro-computational account of how fear interferes with adaptation to volatility during dynamic environments.</p
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