302 research outputs found
Towards Combinatorial Generalization for Catalysts: A Kohn-Sham Charge-Density Approach
The Kohn-Sham equations underlie many important applications such as the
discovery of new catalysts. Recent machine learning work on catalyst modeling
has focused on prediction of the energy, but has so far not yet demonstrated
significant out-of-distribution generalization. Here we investigate another
approach based on the pointwise learning of the Kohn-Sham charge-density. On a
new dataset of bulk catalysts with charge densities, we show density models can
generalize to new structures with combinations of elements not seen at train
time, a form of combinatorial generalization. We show that over 80% of binary
and ternary test cases achieve faster convergence than standard baselines in
Density Functional Theory, amounting to an average reduction of 13% in the
number of iterations required to reach convergence, which may be of independent
interest. Our results suggest that density learning is a viable alternative,
trading greater inference costs for a step towards combinatorial
generalization, a key property for applications.Comment: Published at NeurIPS 202
The identification and evaluation of key sustainable development indicators and the development of a conceptual decision-making model for capital investment within Gold Fields Limited (GFL)
The current trends in sustainable development (SO) were examined in this study, which brought about the realisation that SO has become a business imperative. Mining, which is a highly impacting industry, is faced with the dilemma of implementing the principles of SO despite the realisation that its activities are severely limited by· the finite nature of the resource it is capitalising on. This reality, however, does not detract from the non-negotiable requirement for the industry to meet the increasing pressures to act responsibly towards the environment and the community in which it operates. Gold Fields has stepped up to the plate and has already taken several steps to achieve this end. These include the adoption of SO in its Vision, Values and strategies and the development and implementation of a SO framework to ensure the integration of the principles of SO into the business. Furthermore, Gold Fields has also entered into voluntary activities that further cement the commitment the company has towards so. These other initiatives include, inter alia, its International Council on Mining and Metals membership, UN Global Compact participation, becoming a signatory to the cyanide code, IS014001, and so on. This study focussed on several indicator categories and the identification of a set of supporting sustainable development indicators (SOls) for each, which included environmental, social, economic, technological, and ethics, legal and corporate governance (not in order of priority). These indicators were assessed by a carefully selected group of respondents whose collective wisdom and expertise were used to identify and weight supporting SOls for each of the indicator categories. These supporting SOls were in turn used to develop a model that is able to assist in the business's decision making processes when capital investment is being considered . A water treatment project that is currently being considered by Gold Fields was utilised to demonstrate how the decision making model can be applied to two different scenarios. The result clearly and successfully demonstrated that by proactively taking environmental, economic, social, technological, and ethics, legal and corporate governance considerations into account, a gold mining company is able to increase the level of SO of a capital investment project
Promoting cognitive support technology use and employment success among postsecondary students with traumatic brain injuries
OBJECTIVE: This article applies positive psychology principles to the purpose and objectives of a five-year, federally-funded initiative to provide cognitive support technology (CST) training and career preparatory services for undergraduate college students with mild and moderate traumatic brain injuries (TBI). METHODS: A total of 48 students with TBI have participated in the project during its first 18 months of operation - 14 of whom are military veterans with disabilities who were in the Iraq and/or Afghanistan theaters. CONCLUSION: Positive psychology interventions such as Best Possible Self, Intensely Positive Experiences, and Asset-based Assessments provide a framework for examining the activities of this multi-site development project
The Meis homeoprotein regulates the axolotl Prod 1 promoter during limb regeneration
During limb regeneration in salamanders the blastemal cells give rise only to structures distal to the level of amputation. This proximodistal identity can be regulated by ectopic expression of Meis homeoproteins or the three finger protein Prod 1 which acts at the cell surface. It has been suggested that Meis acts by regulating the transcription of Prod 1. We have sequenced the axolotl Prod 1 promoter and selected two candidate sites for binding Meis homeoproteins. The sites were mutated in various combinations in promoters expressing a luciferase reporter gene. The promoter activity was assayed by nucleofecting AL1 cells, a cultured axolotl limb cell line that expresses both Prod 1 and Meis 1 and 2. The activity of the promoter was inhibited by 60% after mutation at Meis site 1, but not at Meis site 2. The promoter constructs were electroporated into axolotl limb blastemas and the wild type promoter was more active in a proximal blastema than in a contralateral distal blastema. The wild type promoter was significantly more active than a (site 1+site 2) mutant promoter in contralateral proximal blastemas, but the promoters were equivalent in contralateral distal blastemas. The separate site 1 or site 2 mutants were not significantly different from wild type in contralateral proximal blastemas, thus contrasting with the site 1 results in AL1 cells. These data provide strong support for the hypotheses that the Prod 1 promoter is regulated on the proximodistal axis, and that Meis homeoproteins directly regulate the promoter on this axis during limb regeneration in addition to cultured cells
The Hydrogen Epoch of Reionization Array Dish I: Beam Pattern Measurements and Science Implications
The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer
aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen
from the Epoch of Reionization (EOR). Drawing on lessons from the Murchison
Widefield Array (MWA) and the Precision Array for Probing the Epoch of
Reionization (PAPER), HERA is a hexagonal array of large (14 m diameter) dishes
with suspended dipole feeds. Not only does the dish determine overall
sensitivity, it affects the observed frequency structure of foregrounds in the
interferometer. This is the first of a series of four papers characterizing the
frequency and angular response of the dish with simulations and measurements.
We focus in this paper on the angular response (i.e., power pattern), which
sets the relative weighting between sky regions of high and low delay, and
thus, apparent source frequency structure. We measure the angular response at
137 MHz using the ORBCOMM beam mapping system of Neben et al. We measure a
collecting area of 93 m^2 in the optimal dish/feed configuration, implying
HERA-320 should detect the EOR power spectrum at z~9 with a signal-to-noise
ratio of 12.7 using a foreground avoidance approach with a single season of
observations, and 74.3 using a foreground subtraction approach. Lastly we study
the impact of these beam measurements on the distribution of foregrounds in
Fourier space.Comment: 13 pages, 9 figures. Replaced to match accepted ApJ versio
Enhanced response inhibition during intensive meditation training predicts improvements in self-reported adaptive socioemotional functioning.
We examined the impact of training-induced improvements in self-regulation, operationalized in terms of response inhibition, on longitudinal changes in self-reported adaptive socioemotional functioning. Data were collected from participants undergoing 3 months of intensive meditation training in an isolated retreat setting (Retreat 1) and a wait-list control group that later underwent identical training (Retreat 2). A 32-min response inhibition task (RIT) was designed to assess sustained self-regulatory control. Adaptive functioning (AF) was operationalized as a single latent factor underlying self-report measures of anxious and avoidant attachment, mindfulness, ego resilience, empathy, the five major personality traits (extroversion, agreeableness, conscientiousness, neuroticism, and openness to experience), diffi-culties in emotion regulation, depression, anxiety, and psychological well-being. Participants in Retreat 1 improved in RIT performance and AF over time whereas the controls did not. The control participants later also improved on both dimensions during their own retreat (Retreat 2). These improved levels of RIT performance and AF were sustained in follow-up assessments conducted approximately 5 months after the training. Longitudinal dynamic models with combined data from both retreats showed that improvement in RIT performance during training influenced the change in AF over time, which is consistent with a key claim in the Buddhist literature that enhanced capacity for self-regulation is an important precursor of changes in emotional well-being
Metastability in pressure-induced structural transformations of CdSe/ZnS core/shell nanocrystals
The kinetics and thermodynamics of structural transformations under pressure
depend strongly on particle size due to the influence of surface free energy.
By suitable design of surface structure, composition, and passivation it is
possible, in principle, to prepare nanocrystals in structures inaccessible to
bulk materials. However, few realizations of such extreme size-dependent
behavior exist. Here we show with molecular dynamics computer simulation that
in a model of CdSe/ZnS core/shell nanocrystals the core high pressure structure
can be made metastable under ambient conditions by tuning the thickness of the
shell. In nanocrystals with thick shells, we furthermore observe a wurtzite to
NiAs transformation, which does not occur in the pure bulk materials. These
phenomena are linked to a fundamental change in the atomistic transformation
mechanism from heterogenous nucleation at the surface to homogenous nucleation
in the crystal core. Our results suggest a new route towards expanding the
range of available nanoscale materials
Intimate partner violence, interpersonal aggression, and life history strategy
We integrate life history (LH) theory with "hot/cool" systems theory of self-regulation to predict sexually and socially coercive behaviors, including intimate partner violence (IPV) and interpersonal aggression (IPA). LH theory predicts that a variety of traits form LH strategies: adaptively coordinated behavioral clusters arrayed on a continuum from slow to fast. We test structural models examining 2 propositions: (a) "hot" cognitive processes, promoted by faster LH strategies, increase the likelihood of sexually/socially coercive behaviors that make up IPV and IPA; (b) "cool" cognitive processes, promoted by slower LH strategies, buffer against the likelihood of sexually/socially coercive behaviors that make up IPV and IPA. We present single and multisample structural equations models (SEMs and MSEMs) testing hypothesized causal relations among these theoretically specified predictors with IPV and IPA. Study 1 develops a Structural Equation Model for IPV; Study 2 extends the model to IPA using MSEM and provides 5 cross-cultural constructive replications of the findings. Integrating LH theory and hot/cool systems analysis of cognitive processes is a promising and productive heuristic for future research on IPV and IPA perpetration and victimization. </p
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