Abstract
Some of the most common processes in the solar wind, such as turbulence and wave generation by instabilities, are associated with spectral magnetic helicity. Therefore, the helicity is a ...convenient tool to investigate these processes. We use three-dimensional nonlinear kinetic simulations with particle ions and fluid electrons to analyze the magnetic helicity produced by proton temperature anisotropy instabilities coexisting with an ambient turbulence. The symmetry of the unstable system is violated by alpha-particle streaming with respect to protons along the mean magnetic field. At the same time, the turbulent fluctuations are also imbalanced by a nonzero cross-helicity. We show that in the nonlinear phase of the instability the resulting helicity structure is different from the prediction of the linear theory. In particular, it contains sign reversals and multiple domains of nonzero helicity. The turbulence generates its own magnetic helicity signature, which extends over a wide range of angles around the direction perpendicular to the mean magnetic field, and can have a sign the same as or opposite to that of the instability. These findings are consistent with the observed helicity spectra in the solar wind.
Abstract Observational data at heliocentric distances of tens of solar radii suggest that fast magnetosonic modes make up a considerable fraction of the solar wind fluctuations. Furthermore, this ...fraction appears to increase closer to the Sun. We carry out three-dimensional kinetic simulations with particle ions and fluid electrons to evaluate the proton and alpha-particle heating produced by the damping of the fast waves in the solar corona. Realistic parameters at 5 solar radii, including the fluctuation amplitude, are used. We show that, due to the cyclotron resonance, the alphas are heated preferentially perpendicularly to the magnetic field and much more strongly than the protons. The presence of the alpha particles alters the energy partition by reducing the heating of the protons. Nevertheless, the proton heating is sufficient to account for the solar wind acceleration.
Abstract
We investigate a secondary proton beam instability coexisting with the ambient solar wind turbulence at 50
R
☉
. Three-dimensional hybrid numerical simulations (particle ions and a ...quasi-neutralizing electron fluid) are carried out with the plasma parameters in the observed range. In the turbulent background, the particle distribution function, in particular the slope of the “bump-on-tail” responsible for the instability, is time-dependent and inhomogeneous. The presence of the turbulence substantially reduces the growth rate and saturation level of the instability. We derive magnetic power spectra from the observational data and perform a statistical analysis to evaluate the average turbulence intensity at 50
R
☉
. This information is used to link the observed frequency spectrum to the wavenumber spectrum in the simulations. We verify that Taylor’s frozen-in hypothesis is valid for this purpose to a sufficient extent. To reproduce the typical magnetic power spectrum of the instability observed concurrently with the background turbulence, an artificial spacecraft probe is run through the simulation box. The thermal-ion instabilities are often seen as power elevations in the kinetic range of scales above an extrapolation of the turbulence spectrum from larger scales. We show that the elevated power in the simulations is much higher than the background level. Therefore, the turbulence at the average intensity does not obscure the secondary proton beam instability, as opposed to the solar wind at 1 au, in which the ambient turbulence typically obscures thermal-ion instabilities.
•A next-best-view approach based on supervised deep learning is proposed.•It is shown that the next-best-view problem can be addressed as a classification task.•The proposed approach is 1750 times ...faster than state-of-the-art methods.•An original three-dimensional convolutional neural network that learns to predict the next-best-view is introduced.
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Motivated by the advances in 3D sensing technology and the spreading of low-cost robotic platforms, 3D object reconstruction has become a common task in many areas. Nevertheless, the selection of the optimal sensor pose that maximizes the reconstructed surface is a problem that remains open. It is known in the literature as the next-best-view planning problem. In this paper, we propose a novel next-best-view planning scheme based on supervised deep learning. The scheme contains an algorithm for automatic generation of datasets and an original three-dimensional convolutional neural network (3D-CNN) used to learn the next-best-view. Unlike previous work where the problem is addressed as a search, the trained 3D-CNN directly predicts the sensor pose. We present an experimental comparison of the proposed architecture against two alternative networks; we also compare it with state-of-the-art next-best-view methods in the reconstruction of several unknown objects. Our method is faster and reaches high coverage.
This article memorializes Josephine D. Johnson (1951–2023), clinical psychologist. Johnson contributed significantly to the evolution of multicultural psychology. She served as Chair of the American ...Psychological Association (APA) Task Force on the Implementation of the Multicultural Guidelines. Highlights of Johnson's career and her professional contributions are noted. (PsycInfo Database Record (c) 2024 APA, all rights reserved)
Abstract
We revisit the question of how the unstable scattering of interstellar pickup ions (PUIs) may drive turbulence in the outer solar wind and why the energy released into fluctuations by this ...scattering appears to be significantly less than the standard bispherical prediction. We suggest that energization of the newly picked-up ions by the ambient turbulence during the scattering process can result in a more spherical distribution of PUIs and reduce the generated fluctuation energy to a level consistent with the observations of turbulent intensities and core solar wind heating. This scenario implies the operation of a self-regulation mechanism that maintains the observed conditions of turbulence and heating in the PUI-dominated solar wind.
Psychology and Social Justice Vasquez, Melba J. T
The American psychologist,
07/2012, Letnik:
67, Številka:
5
Journal Article
Recenzirano
Much of psychological science and knowledge is significantly relevant to social justice, defined here as the goal to decrease human suffering and to promote human values of equality and justice. A ...commitment to social justice has evolved as a more important value in the last few decades for psychology, including for the American Psychological Association (APA). The mission, vision, goals, Ethics Code, and strategic plan of APA all provide a rationale for psychologists' involvement in systematic and visible ways of applying our knowledge to social issues. Although psychology has not been immune to the application of psychological knowledge in destructive ways, overall, psychology, many psychologists, and APA have demonstrated a commitment to social justice. This article provides a brief review of the key proponents, debates, and controversies involved in applying psychological science and knowledge to complex societal problems. Psychologists often find themselves in conflict and honest disagreement when the association addresses complex and controversial issues. An important goal is that we continue to find ways to agree or disagree in a respectful manner regardless of where each of us stands on the various positions that APA takes.
•Child-friendly COVID-19 vaccination programs can support primary school children.•Families accessed bespoke COVID-19 vaccine pathways, information, and preparatory resources.•Parent/guardian ...satisfaction was high, both overall and for priority communities.•Department of Health Immunisation plan usage was higher in priority communities.•Tailored vaccine programs could be used for younger children or for other childhood vaccines.
Procedural anxiety was anticipated in children 5–11 years during the COVID-19 vaccine rollout in Victoria, Australia, as children in this age group receive few routine vaccines. Therefore, the Victorian state government designed a tailored, child-friendly vaccine program. This study aimed to assess parental satisfaction with elements of the bespoke vaccination pathway.
The Victorian government and state-run vaccination hubs in Victoria facilitated an online immunisation plan to help parents identify their child’s support needs, and utilised experienced paediatric staff and additional supports for children with severe needle distress and/or disability. All parents/guardians of children 5–11 years who received a COVID-19 vaccine in a vaccination hub were sent a 16-item feedback survey via text message.
Between 9 February and 31 May 2022 there were 9203 responses; 865 children (9.4%) had a first language other than English, 499 (5.4%) had a disability or special needs, and 142 (1.5%) were Aboriginal or Torres Strait Islander. Most parents (94.4%; 8687/9203) rated their satisfaction with the program as very good or excellent. The immunisation plan was used by 13.5% (1244/9203) of respondents, with usage more common for Aboriginal or Torres Strait Islander children (26.1%; 23/88) or families with a first language other than English (23.5%; 42/179). The child-friendly staff (88.5%, 255/288) and themed environment (66.3%, 191/288) were the most valued measures for vaccination. Additional support measures were required by 1.6% (150/9203) of children in the general population and 7.9%, (17/261) of children with a disability and/or special needs.
A tailored COVID-19 vaccination program for children 5–11 years, with additional support for children with severe needle distress and/or disability, had high parental satisfaction. This model could be utilised for COVID-19 vaccination in pre-school children and for routine childhood vaccination programs to provide optimal support to children and their families.
•Safety training using salient cues improves safety learning in high anxiety mice.•Salient Safety training improves novel fear discrimination learning.•Safety training improves exploration in a novel ...anxiogenic environment.
Generalized fear is one purported mechanism of anxiety that is a target of clinical and basic research. Impaired fear discrimination has been primarily examined from the perspective of increased fear learning, rather than how learning about non-threatening stimuli affects fear discrimination. To address this question, we tested how three Safety Conditioning protocols with varied levels of salience allocated to the safety cue compared to classic Fear Conditioning in their impact on subsequent innate anxiety, and differential fear learning of new aversive and neutral cues. Using a high anxiety strain of mice (129SvEv, Taconic), we show that Fear Conditioned animals show little exploration of the anxiogenic center of an open field 24 h later, and poor discrimination during new differential conditioning 7 days later. Three groups of mice underwent Safety Conditioning, (i) the safety tone was unpaired with a shock, (ii) the safety tone was unpaired with the shock and co-terminated with a house light signaling the end of the safety period, and (iii) the safety tone was unpaired with the shock and its beginning co-occurred with a house light, signaling the start of a safety period. Mice from all Safety Conditioning groups showed higher levels of open field exploration than the Fear Conditioned mice 24 h after training. Furthermore, Safety Conditioned animals showed improved discrimination learning of a novel non-threat, with the Salient Beginning safety conditioned group performing best. These findings indicate that high anxiety animals benefit from salient safety training to improve exploration and discrimination of new non-threating stimuli.
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