Poling of VDF/TrFe copolymers using a step-wise method

A new poling technique is presented, in which a series of five consecutive pulses of electric field, and with successively increasing strength is applied between the two electrodes of 65/35 VDF/TrFE copolymer based sensor. Between each pulse, the applied electric field is reduced to zero (short circuit). This allows deformations and space charges to be relax, resulting in more homogeneous electric field distribution with less risk for an electric breakdown. It is conducted at room temperature and is compatible with semiconductor technology. This step-wise poling technique is characterised by a low breakdown rate and yields a high pyroelectric coefficien

Motivation as a predictor of dental students’ affective and behavioral outcomes: Does the quality of motivation matter?

Since the motivation to study and engage in academic activities plays a key role in students’ learning experience and well-being, gaining a better understanding of dental students’ motivations can help educators implement interventions to support students’ optimal motivations. The aim of this study, grounded in self-determination theory, was to determine the predictive role of different types of motivation (autonomous motivation, controlled motivation, and amotivation) in the affective and behavioral outcomes of dental students. Amotivation is the absence of drive to pursue an activity due to a failure to establish relationships between activity and behavior; controlled motivation involves behaving under external pressure or demands; and autonomous motivation is an internalized behavior with a full sense of volition, interest, choice, and self-determination. A cross-sectional correlational study was conducted in 2016, in which 924 students (90.2% response rate) from years one to six agreed to participate, granting permission to access their current GPAs and completing four self-reported questionnaires on academic motivation, study strategies, vitality, and self-esteem. The results showed that self-determined motivation (i.e., autonomous over controlled motivation) was positively associated with vitality, self-esteem, and deep study strategies and negatively associated with surface study strategies. The contrary results were found for amotivation. In the motivational model, deep study strategies showed a positive association with students’ academic performance. Contrary results were found for surface study strategies. This study extends understanding of the differentiation of motivation based on its quality types and suggests that being motivated does not necessarily lead to positive educational outcomes. Autonomous motivation, in contrast to controlled motivation and amotivation, should be supported to benefit students with regard to their approaches to learning and well-being since it can promote students’ vitality, self-esteem, deep over surface study strategies, and enhanced academic performance

Analysis of Transverse Momentum Correlations in Hadronic Z Decays

Analysis of Transverse Momentum Correlations in Hadronic Z Decays The ALEPH Collaboration In recent paper, evidence was presented for a significant, positive correlation between the total transverse momenta of particles on opposite sides of hadronic events. From comparisons with Monte Carlo generators it was concluded that there were both non-peturbative and perturbative contributions to this correlation. A new, model independent analysis of the data has been made. Two components can be distinguished in the correlation. Quantitative estimates of each are given. The results form a significant test of Monte Carlo models and some of the physics behind them

Neogene fluvial landscape evolution in the hyperarid core of the Atacama Desert

Dating of extensive alluvial fan surfaces and fluvial features in the hyperarid core of the Atacama Desert, Chile, using cosmogenic nuclides provides unrivalled insights about the onset and variability of aridity. The predominantly hyperarid conditions help to preserve the traces of episodic climatic and/or slow tectonic change. Utilizing single clast exposure dating with cosmogenic 10Be and 21Ne, we determine the termination of episodes of enhanced fluvial erosion and deposition occurring at ~19, ~14, ~9.5 Ma; large scale fluvial modification of the landscape had ceased by ~2–3 Ma. The presence of clasts that record pre-Miocene exposure ages (~28 Ma and ~34 Ma) require stagnant landscape development during the Oligocene. Our data implies an early onset of (hyper-) aridity in the core region of the Atacama Desert, interrupted by wetter but probably still arid periods. The apparent conflict with interpretation that favour a later onset of (hyper-) aridity can be reconciled when the climatic gradients within the Atacama Desert are considered

COVID-19 research in critical care: the good, the bad, and the ugly

The extraordinary pace of research on coronavirus disease 2019 (COVID-19) has been one of the major success stories of the pandemic. Therapeutic trials involving thousands of patients, which usually take years to complete, have been reported in a matter of months. National and international registries and networks have reported on tens of thousands of patients in near real time. However, there have also been many challenges: hundreds of trials have been underpowered, duplicated, or of poor quality; excessive bureaucracy has complicated study initiation; and only a small percentage of eligible patients worldwide have been enrolled in studies, while many others have been treated with off-label, unproven therapies. All of this has been complicated by an “infodemic” of low-quality medical information, accelerated by social media.info:eu-repo/semantics/publishedVersio

Bulk and surface energetics of lithium hydride crystal: benchmarks from quantum Monte Carlo and quantum chemistry

We show how accurate benchmark values of the surface formation energy of crystalline lithium hydride can be computed by the complementary techniques of quantum Monte Carlo (QMC) and wavefunction-based molecular quantum chemistry. To demonstrate the high accuracy of the QMC techniques, we present a detailed study of the energetics of the bulk LiH crystal, using both pseudopotential and all-electron approaches. We show that the equilibrium lattice parameter agrees with experiment to within 0.03 %, which is around the experimental uncertainty, and the cohesive energy agrees to within around 10 meV per formula unit. QMC in periodic slab geometry is used to compute the formation energy of the LiH (001) surface, and we show that the value can be accurately converged with respect to slab thickness and other technical parameters. The quantum chemistry calculations build on the recently developed hierarchical scheme for computing the correlation energy of a crystal to high precision. We show that the hierarchical scheme allows the accurate calculation of the surface formation energy, and we present results that are well converged with respect to basis set and with respect to the level of correlation treatment. The QMC and hierarchical results for the surface formation energy agree to within about 1 %.Comment: 16 pages, 4 figure

Early serial EEG in hypoxic ischaemic encephalopathy

Objectives: To perform early serial EEGs in infants with hypoxic ischaemic encephalopathy (HIE) and compare the findings with neurodevelopmental outcome.// Methods: Nine full-term neonates with HIE had simultaneous video-EEG polygraphic studies within 8 h of birth. The EEG was repeated at 12–24 h intervals. All surviving infants had a neurodevelopmental assessment at 1 year.// Results: Two infants had a normal or mildly abnormal EEG within 8 h of birth and neurodevelopmental outcome was normal. Seven infants had severely depressed background activity in the first 8 h of life. In 3 infants the EEG activity recovered within 12–24 h showing continuous activity with no or only minor abnormalities. All these infants had a normal outcome. The remaining 4 infants, who also had an initially inactive recording, subsequently developed severe background abnormalities. At follow-up, two infants had died and the remainder developed major neurological sequelae.// Conclusions: Early EEG is an excellent prognostic indicator for a favourable outcome if normal within the first 8 h of life and for a poor outcome if the background activity continues to be inactive or grossly abnormal beyond 8–12 h of life. However, an inactive or very depressed EEG within the first 8 h of life can be associated with good outcome if the EEG activity recovers within 12 h

Measurement of the ΔS=-ΔQ Amplitude from K_(e3)^0 Decay

We have measured the time distribution of the π^+e^-ν and π^-e^+ν modes from initial K^0's in a spark-chamber experiment performed at the Bevatron. From 1079 events between 0.2 and 7 K_S^0 lifetime, we find ReX=-0.069±0.036, ImX=+0.108_(-0.074)^(+0.092). This result is consistent with X=0 (relative probability = 0.25), but more than 4 standard deviations from the existing world average, +0.14 -0.13i

Treatment of interictal epileptiform discharges can improve behavior in children with behavioral problems and epilepsy

Objectives: It is generally agreed that children should be treated for epilepsy only if they have clinical seizures. The aim of this study was to examine whether suppressing interictal discharges can affect behavior in children with epilepsy.// Study design: In a double-blinded, placebo-controlled, crossover study, 61 children with well-controlled or mild epilepsy were randomly assigned to add-on therapy with either lamotrigine followed by placebo or placebo followed by lamotrigine. Ambulatory electroencephalographic recordings and behavioral scales were performed during baseline and at the end of placebo and drug phases. The primary hypothesis to be tested was that behavioral scales would improve specifically in patients with a reduction of electroencephalographic discharges during active drug treatment.// Results: Global rating of behavior significantly improved only in patients who showed a significant reduction in either frequency (P < .05) or duration of discharges (P < .05) during active treatment but not in patients with without a significant change in discharge rate. This improvement was mainly seen in patients with partial epilepsy (P < .005).// Conclusions: Our data suggest that suppressing interictal discharges can improve behavior in children with epilepsy and behavioral problems, particularly partial epilepsy. Focal discharges may be involved in the underlying mechanisms of behavioral problems in epilepsy

Evidence for multiple Plio-Pleistocene lake episodes in the hyperarid Atacama Desert

Cosmogenic nuclide exposure dating of ancient shoreline terraces of the Quillagua-Llamara Soledad Lake in the central Atacama Desert of northern Chile provides new insights in the paleohydrology of the driest desert on Earth. The lake developed in a paleo-endorheic drainage system in the Central Depression prior to draining into the Pacific due to incision of the Río Loa canyon. The durations of lake stages were sufficiently long to form wave-erosion induced shoreline terraces on the wind-exposed slopes of former islands. Successively younger shoreline levels are preserved over an elevation range of 250 m due to progressive uplift of the islands coeval with the lake stages. Cosmogenic 10Be- and 21Ne-derived exposure ages of the shorelines reveals that the hyperarid conditions in the Río Loa catchment were interspersed by several pluvial stages during the Pliocene and Pleistocene, which generated a large and persistent lake in the Quillagua-Llamara basin. The exposure ages of the final lake stage provide the maximum age for the incision of the Río Loa canyon (274 ± 74 ka) and the subsequent breaching of the Coastal Cordillera