99 research outputs found
Reuse of Neural Modules for General Video Game Playing
A general approach to knowledge transfer is introduced in which an agent
controlled by a neural network adapts how it reuses existing networks as it
learns in a new domain. Networks trained for a new domain can improve their
performance by routing activation selectively through previously learned neural
structure, regardless of how or for what it was learned. A neuroevolution
implementation of this approach is presented with application to
high-dimensional sequential decision-making domains. This approach is more
general than previous approaches to neural transfer for reinforcement learning.
It is domain-agnostic and requires no prior assumptions about the nature of
task relatedness or mappings. The method is analyzed in a stochastic version of
the Arcade Learning Environment, demonstrating that it improves performance in
some of the more complex Atari 2600 games, and that the success of transfer can
be predicted based on a high-level characterization of game dynamics.Comment: Accepted at AAAI 1
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Competition and forgetting during context-based episodic memory retrieval
Recent memory models highlight the importance of contextual information for remembering episodic events. A consequence of binding event memories with their context is that contextually related memories can interfere with the retrieval of targeted memories, leading to retrieval induced forgetting (RIF) of the competing memories (Anderson et al., 2000). A model built to explain this effect describes a nonmonotonic “U shaped” relationship between memory activation and changes in memory strength (Norman et al., 2007). Specifically, competing memories that activate to a moderate degree (vs. low or high activation) are more likely to be weakened and forgotten. However, the factors governing whether and how memories will activate and compete during retrieval are not well understood. Here, we test the hypothesis that events experienced closer in time will be more likely to compete during memory retrieval, leading to RIF.Psycholog
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Ozone effects on blood biomarkers of systemic inflammation, oxidative stress, endothelial function, and thrombosis: The Multicenter Ozone Study in oldEr Subjects (MOSES).
The evidence that exposure to ozone air pollution causes acute cardiovascular effects is mixed. We postulated that exposure to ambient levels of ozone would increase blood markers of systemic inflammation, prothrombotic state, oxidative stress, and vascular dysfunction in healthy older subjects, and that absence of the glutathione S-transferase Mu 1 (GSTM1) gene would confer increased susceptibility. This double-blind, randomized, crossover study of 87 healthy volunteers 55-70 years of age was conducted at three sites using a common protocol. Subjects were exposed for 3 h in random order to 0 parts per billion (ppb) (filtered air), 70 ppb, and 120 ppb ozone, alternating 15 min of moderate exercise and rest. Blood was obtained the day before, approximately 4 h after, and approximately 22 h after each exposure. Linear mixed effect and logistic regression models evaluated the impact of exposure to ozone on pre-specified primary and secondary outcomes. The definition of statistical significance was p<0.01. There were no effects of ozone on the three primary markers of systemic inflammation and a prothrombotic state: C-reactive protein, monocyte-platelet conjugates, and microparticle-associated tissue factor activity. However, among the secondary endpoints, endothelin-1, a potent vasoconstrictor, increased from pre- to post-exposure with ozone concentration (120 vs 0 ppb: 0.07 pg/mL, 95% confidence interval [CI] 0.01, 0.14; 70 vs 0 ppb: -0.03 pg/mL, CI -0.09, 0.04; p = 0.008). Nitrotyrosine, a marker of oxidative and nitrosative stress, decreased with increasing ozone concentrations, with marginal significance (120 vs 0 ppb: -41.5, CI -70.1, -12.8; 70 vs 0 ppb: -14.2, CI -42.7, 14.2; p = 0.017). GSTM1 status did not modify the effect of ozone exposure on any of the outcomes. These findings from healthy older adults fail to identify any mechanistic basis for the epidemiologically described cardiovascular effects of exposure to ozone. The findings, however, may not be applicable to adults with cardiovascular disease
Epic Aspects of Retail Encounters: The Iliad of Hollister
Much has been written about myth and the marketplace. Consumer research has added immeasurably to academics’ appreciation of the myths that inhere in fabulous flagship stores and experiential retailing more generally. Studies of consumer mythopoeia, however, have tended to muffle the martial side of retailing, the heroic struggles that some customers undergo in-store. This article argues that the epic offers valuable insights into martial matters, and more. Although epic and myth overlap, they are far from identical. The former is characterized by conventions that can help illuminate consumers’ quests, not least their disturbing journeys through the underworld. These are considered in relation to Hollister (HCo), a phenomenally successful retail chain that’s renowned for its antithetical atmospherics and inky interior design. A qualitative study of Hollister lovers and haters casts light on the epic in action and adds to scholars’ understanding of immersive retailing experiences
Discovery and functional prioritization of Parkinson's disease candidate genes from large-scale whole exome sequencing.
BACKGROUND: Whole-exome sequencing (WES) has been successful in identifying genes that cause familial Parkinson's disease (PD). However, until now this approach has not been deployed to study large cohorts of unrelated participants. To discover rare PD susceptibility variants, we performed WES in 1148 unrelated cases and 503 control participants. Candidate genes were subsequently validated for functions relevant to PD based on parallel RNA-interference (RNAi) screens in human cell culture and Drosophila and C. elegans models. RESULTS: Assuming autosomal recessive inheritance, we identify 27 genes that have homozygous or compound heterozygous loss-of-function variants in PD cases. Definitive replication and confirmation of these findings were hindered by potential heterogeneity and by the rarity of the implicated alleles. We therefore looked for potential genetic interactions with established PD mechanisms. Following RNAi-mediated knockdown, 15 of the genes modulated mitochondrial dynamics in human neuronal cultures and four candidates enhanced α-synuclein-induced neurodegeneration in Drosophila. Based on complementary analyses in independent human datasets, five functionally validated genes-GPATCH2L, UHRF1BP1L, PTPRH, ARSB, and VPS13C-also showed evidence consistent with genetic replication. CONCLUSIONS: By integrating human genetic and functional evidence, we identify several PD susceptibility gene candidates for further investigation. Our approach highlights a powerful experimental strategy with broad applicability for future studies of disorders with complex genetic etiologies
Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures
Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo
Performance and health effects of Zuprevo 18% in newly received, highly stressed beef cattle
The objective of this study was to determine the health and performance effects of
Zuprevo 18% (tildipirosin, 4 mg/kg body weight) during a 42-day backgrounding
period when administered to high-risk transported cattle within 24 hours after arrival
Oral administration of an integrative supplement (CogniCaps®) improves cognitive scores in aging dogs with canine cognitive dysfunction for at least two months: An open-label investigation in ten dogs.
Background: Canine cognitive dysfunction (CCD), the dog analog of human Alzheimer's disease (AD), is a progressive neurodegenerative condition that presents many treatment challenges. There are few effective drugs with acceptable side effects for AD/CCD, which has prompted investigation into non-drug options, collectively termed nutraceuticals. Nutraceutical supplements are conceptually divided into conventional (Western) and non-conventional (Eastern) ingredients. Many of these individual supplements have shown in vitro and/or in vivo efficacy in ameliorating neuronal damage in rodent models, and some have demonstrated positive effects on cognition in rodent models and clinical trials in dogs and humans with cognitive impairment.
Aim: The purpose of this open-label clinical trial was to investigate the effect of an oral integrative (combination of conventional nutraceuticals and Chinese herbals) supplement (CogniCaps®) on cognitive scores when administered to aging dogs with CCD over a 2-month period.
Methods: Ten older (>9-year-old) dogs with presumptive CCD and moderate (16-33) or severe (>33) cognitive scores were recruited and administered oral CogniCaps® for two months. No additional drugs or nutraceuticals directed at improving cognitive function were allowed during the study period. Baseline cognitive scores were compared with those procured at 30 and 60 days. Cognitive scores for baseline, 30- and 60-days post-treatment were compared.
Results: Cognitive scores improved at 30 days (37% reduction) and 60 days (41% reduction) post-treatment (p=0.002). Scores did not differ between 30-and 60-day assessments (p=0.7).
Conclusion: The results of this small study suggest that the integrative supplement CogniCaps® might improve cognitive scores in dogs with CCD within the first 30 days of administration and that this improvement is sustained at 60-day follow up. [Open Vet J 2023; 13(2.000): 188-192
Dissociable largescale networks anchored in the right anterior insula subserve affective experience and attention
Meta-analytic summaries of neuroimaging studies point to at least two major functional-anatomic subdivisions within the anterior insula that contribute to the detection and processing of salient information: a dorsal region that is routinely active during attention tasks and a ventral region that is routinely active during affective experience. In two independent samples of cognitively normal human adults, we used intrinsic functional connectivity magnetic resonance imaging to demonstrate that the right dorsal and right ventral anterior insula are nodes in separable large-scale functional networks. Furthermore, stronger intrinsic connectivity within the right dorsal anterior insula network was associated with better performance on a task involving attention and processing speed whereas stronger connectivity within the right ventral anterior insula network was associated with more intense affective experience. These results support the hypothesis that the identification and manipulation of salient information is subserved by at least two brain networks anchored in the right anterior insula that exhibit distinct large-scale topography and dissociable behavioral correlates
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