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Positive reinforcement

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https://www.readbyqxmd.com/read/29784820/efficient-collective-swimming-by-harnessing-vortices-through-deep-reinforcement-learning
#1
Siddhartha Verma, Guido Novati, Petros Koumoutsakos
Fish in schooling formations navigate complex flow fields replete with mechanical energy in the vortex wakes of their companions. Their schooling behavior has been associated with evolutionary advantages including energy savings, yet the underlying physical mechanisms remain unknown. We show that fish can improve their sustained propulsive efficiency by placing themselves in appropriate locations in the wake of other swimmers and intercepting judiciously their shed vortices. This swimming strategy leads to collective energy savings and is revealed through a combination of high-fidelity flow simulations with a deep reinforcement learning (RL) algorithm...
May 21, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29783121/the-influence-of-nail-blocking-conditions-in-cattle-femoral-fractures
#2
Leopoldo A Paolucci, Estevam B Las Casas, Rafael R Faleiros, Cahuê F R Paz, Sergio S Rocha Junior
BACKGROUND: To investigate the effect of different fixation strategies of the intramedullary interlocking nail (IIN) on the mechanical behavior of a polymeric implant applied for femoral fracture fixation in calves, and to evaluate the performance of a glass fiber-reinforced polymer applied in a bovine femoral fracture reduction system, five Holstein male animals with a mean weight (±SD) of 62.8 ± 20.4 kg and aged 74 ± 15 were used to generate biomechanical parameters for this study...
May 7, 2018: Research in Veterinary Science
https://www.readbyqxmd.com/read/29782516/how-a-smiley-protects-health-a-pilot-intervention-to-improve-hand-hygiene-in-hospitals-by-activating-injunctive-norms-through-emoticons
#3
Susanne Gaube, Dimitrios Tsivrikos, Daniel Dollinger, Eva Lermer
Hand hygiene practice in hospitals is unfortunately still widely insufficient, even though it is known that transmitting pathogens via hands is the leading cause of healthcare-associated infections. Previous research has shown that improving knowledge, providing feedback on past behaviour and targeting social norms are promising approaches to improve hand hygiene practices. The present field experiment was designed to direct people on when to perform hand hygiene and prevent forgetfulness. This intervention is the first to examine the effect of inducing injunctive social norms via an emoticon-based feedback system on hand hygiene behaviour...
2018: PloS One
https://www.readbyqxmd.com/read/29781180/identifying-predictive-behavioral-markers-a-demonstration-using-automatically-reinforced-self-injurious-behavior
#4
Louis P Hagopian, Griffin W Rooker, Gayane Yenokyan
Predictive biomarkers (PBioMs) are objective biological measures that predict response to medical treatments for diseases. The current study translates methods used in the field of precision medicine to identify PBioMs to identify parallel predictive behavioral markers (PBMs), defined as objective behavioral measures that predict response to treatment. We demonstrate the utility of this approach by examining the accuracy of two PBMs for automatically reinforced self-injurious behavior (ASIB). Results of the analysis indicated both functioned as good to excellent PBMs...
May 21, 2018: Journal of Applied Behavior Analysis
https://www.readbyqxmd.com/read/29780881/nucleus-accumbens-microcircuit-underlying-d2-msn-driven-increase-in-motivation
#5
Carina Soares-Cunha, Bárbara Coimbra, Ana Verónica Domingues, Nivaldo Vasconcelos, Nuno Sousa, Ana João Rodrigues
The nucleus accumbens (NAc) plays a central role in reinforcement and motivation. Around 95% of the NAc neurons are medium spiny neurons (MSNs), divided into those expressing dopamine receptor D1 (D1R) or dopamine receptor D2 (D2R). Optogenetic activation of D2-MSNs increased motivation, whereas inhibition of these neurons produced the opposite effect. Yet, it is still unclear how activation of D2-MSNs affects other local neurons/interneurons or input terminals and how this contributes for motivation enhancement...
March 2018: ENeuro
https://www.readbyqxmd.com/read/29778945/self-administration-of-the-synthetic-cathinone-mpdv-enhances-reward-function-via-a-nicotinic-receptor-dependent-mechanism
#6
Jean R Geste, Marjory Pompilus, Marcelo Febo, Adriaan W Bruijnzeel
Methylenedioxypyrovalerone (MDPV) is an addictive synthetic drug with severe side effects. Previous studies have shown that MDPV has positive reinforcing properties. However, little is known about the effect of MDPV self-administration on the state of the brain reward system and the neuronal mechanisms by which MDPV mediates its effects. The goal of the present studies was to determine the effect of MDPV self-administration on reward function and the role of cholinergic neurotransmission in the reinforcing effects of MDPV...
May 9, 2018: Neuropharmacology
https://www.readbyqxmd.com/read/29778803/age-affects-reinforcement-learning-through-dopamine-based-learning-imbalance-and-high-decision-noise-not-through-parkinsonian-mechanisms
#7
Ravi B Sojitra, Itamar Lerner, Jessica R Petok, Mark A Gluck
Probabilistic reinforcement learning declines in healthy cognitive aging. While some findings suggest impairments are especially conspicuous in learning from rewards, resembling deficits in Parkinson's disease, others also show impairments in learning from punishments. To reconcile these findings, we tested 252 adults from 3 age groups on a probabilistic reinforcement learning task, analyzed trial-by-trial performance with a Q-reinforcement learning model, and correlated both fitted model parameters and behavior to polymorphisms in dopamine-related genes...
April 19, 2018: Neurobiology of Aging
https://www.readbyqxmd.com/read/29777827/is-reward-prediction-error-encoding-reliable-during-development
#8
Hanna Keren, Gang Chen, Brenda Benson, Monique Ernst, Ellen Leibenluft, Nathan A Fox, Daniel S Pine, Argyris Stringaris
Reward Prediction Errors (RPEs), defined as the difference between the expected and received outcomes, are integral to reinforcement learning models and play an important role in development and psychopathology. In humans, RPE encoding can be estimated using fMRI recordings, however, a basic measurement property of RPE signals, their test-retest reliability across different time scales, remains an open question. In this paper, we examine the 3-month and 3-year reliability of RPE encoding in youth (mean age at baseline = 10...
May 16, 2018: NeuroImage
https://www.readbyqxmd.com/read/29777810/bacterial-cellulose-nanofibers-as-reinforce-in-edible-fish-myofibrillar-protein-nanocomposite-films
#9
Bahareh Shabanpour, Mohsen Kazemi, Seyed Mahdi Ojagh, Parastoo Pourashouri
Bacterial cellulose nanofibers (BCNF) were employed in order to improve various properties of fish myofibrillar protein (FMP) films of Silver carp. Three different levels (2, 4 and 6%, w/w) of the nanoparticles were added to the protein polymer substrate. In this regard, it became clear that 6% BCNF-containing nanocomposites had the highest tensile strength, which was about 49% better than control samples. The nanoparticles had positive impact on the physical properties; BCNF-containing films showed a reduction in water vapor permeability, swelling and solubility indexes...
May 16, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29777289/tobacco-smoking-may-delay-habituation-of-reinforcer-effectiveness-in-humans
#10
Joshua L Karelitz, Kenneth A Perkins
BACKGROUND: The effectiveness of nonconsummatory reinforcers habituate, as their ability to maintain reinforced responding declines over repeated presentations. Preclinical research has shown that nicotine can delay habituation of reinforcer effectiveness, but this effect has not been directly demonstrated in humans. OBJECTIVE: In preliminary translational research, we assessed effects of nicotine from tobacco smoking (vs. a no smoking control) on within-session patterns of responding for a brief visual reinforcer...
May 18, 2018: Psychopharmacology
https://www.readbyqxmd.com/read/29777172/contrasting-patterns-of-runx2-repeat-variations-are-associated-with-palate-shape-in-phyllostomid-bats-and-new-world-primates
#11
Tiago Ferraz, Daniela M Rossoni, Sérgio L Althoff, Alcides Pissinatti, Vanessa R Paixão-Cortês, Maria Cátira Bortolini, Rolando González-José, Gabriel Marroig, Francisco M Salzano, Gislene L Gonçalves, Tábita Hünemeier
Establishing the genetic basis that underlies craniofacial variability in natural populations is one of the main topics of evolutionary and developmental studies. One of the genes associated with mammal craniofacial variability is RUNX2, and in the present study we investigated the association between craniofacial length and width and RUNX2 across New World bats (Phyllostomidae) and primates (Catarrhini and Platyrrhini). Our results showed contrasting patterns of association between the glutamate/alanine ratios (Q/A ratio) and palate shape in these highly diverse groups...
May 18, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29776744/discovering-mental-models-and-frames-in-learning-of-nursing-ethics-through-simulations
#12
J L Díaz Agea, M R Martín Robles, D Jiménez Rodríguez, I Morales Moreno, I Viedma Viedma, C Leal Costa
The acquisition of ethical competence is necessary in nursing. The aims of the study were to analyse students' perceptions of the process of learning ethics through simulations and to describe the underlying frames that inform the decision making process of nursing students. A qualitative study based on the analysis of simulated experiences and debriefings of six simulated scenarios with ethical content in three different groups of fourth-year nursing students (n = 30), was performed. The simulated situations were designed to contain ethical dilemmas...
May 15, 2018: Nurse Education in Practice
https://www.readbyqxmd.com/read/29776478/perceptions-of-health-care-professionals-on-the-effects-of-residential-summer-camp-in-their-patients
#13
P Galen DiDomizio, Ann Gillard
PURPOSE: A growing body of literature exists regarding medical specialty camps for children. However, very little of the research focuses on the perspectives of healthcare providers. This study explored perceptions of pediatric healthcare providers on a medical specialty camp for children. DESIGN AND METHODS: Interviews with five volunteer physicians and five nurses were conducted and analyzed using inductive content analysis. RESULTS: Results showed that healthcare providers perceived camp to be a positive influence on campers' normalization and healthcare ownership, and to strengthen patient-provider relationships...
May 2018: Journal of Pediatric Nursing
https://www.readbyqxmd.com/read/29776367/malaria-determining-risk-factors-at-the-household-level-in-two-rural-villages-of-mainland-equatorial-guinea
#14
Mónica Guerra, Bruno de Sousa, Nicolas Ndong-Mabale, Pedro Berzosa, Ana Paula Arez
BACKGROUND: After the introduction of an artemisinin-based combination therapy, the reduction of prevalence of malaria infections has shown a remarkable progress during the last decade. However due to the lack of a consistent malaria control programme and socioeconomic inequalities, Plasmodium infection is still one of the major cause of disease in Equatorial Guinea, namely in the rural communities. This study explored the associated risk factors of malaria transmission at the microeconomic level (households) in two rural villages of mainland Equatorial Guinea...
May 18, 2018: Malaria Journal
https://www.readbyqxmd.com/read/29773807/risk-factors-associated-with-htlv-1-vertical-transmission-in-brazil-longer-breastfeeding-higher-maternal-proviral-load-and-previous-htlv-1-infected-offspring
#15
Arthur M Paiva, Tatiane Assone, Michel E J Haziot, Jerusa Smid, Luiz Augusto M Fonseca, Olinda do Carmo Luiz, Augusto Cesar Penalva de Oliveira, Jorge Casseb
HTLV-1 is transmitted primarily either through sexual intercourse or from mother to child. The mother/child pairs were classified as seroconcordant or serodiscordant. We analyzed mother to child transmission (MTCT) according to sociodemographic, clinical and epidemiological characteristics of the mother, child's gender and duration of breastfeeding. Between June 2006 and August 2016 we followed 192 mothers with HTLV-1 infection (mean age 41 years old), resulting in 499 exposed offspring, 288 (57.7%) of whom were tested for HTLV-1, making up the final sample for the study, along with their 134 respective mothers...
May 17, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29773399/dual-physically-crosslinked-healable-polyacrylamide-cellulose-nanofibers-nanocomposite-hydrogels-with-excellent-mechanical-properties
#16
Jiabao Niu, Jianquan Wang, Xiaofu Dai, Ziqiang Shao, Xiaonan Huang
To develop healable hydrogels with excellent mechanical properties is still a challenge topic. In this study, a novel class of physically crosslinked polyacrylamide based nanocomposite hydrogels reinforced with cellulose nanofibers (CNF) were fabricated using radical polymerization, followed by further strengthening through ferric ions via strong ionic coordination interactions between Fe3+ and carboxyls on CNF surfaces. Then the obtained gels were characterized by FTIR, tensile and compressive measurements as well as healing experiments...
August 1, 2018: Carbohydrate Polymers
https://www.readbyqxmd.com/read/29771561/mood-selectively-moderates-the-implicit-alcohol-association-drinking-relation-in-college-student-heavy-episodic-drinkers
#17
Kristen P Lindgren, Jason J Ramirez, Reinout W Wiers, Bethany A Teachman, Jeanette Norris, Cecilia C Olin, Melissa L Gasser, Debra Kaysen, Clayton Neighbors
Multiple studies indicate that implicit alcohol-related associations (i.e., indices of relatively fast, spontaneous processes) predict drinking. An important next step is to investigate moderators of the implicit association-drinking relationship. Mood state has been proposed as a moderator of this relationship: implicit associations have been theorized to be stronger predictors of drinking under positive mood states. From the same theoretical perspective, explicit measures (indices of relatively slow, reflective processes) have been proposed to be stronger predictors of drinking under negative mood states...
May 2018: Psychology of Addictive Behaviors: Journal of the Society of Psychologists in Addictive Behaviors
https://www.readbyqxmd.com/read/29766361/genetic-dissection-of-the-brca2-promoter-and-transcriptional-impact-of-dna-variants
#18
Eugenia Fraile-Bethencourt, Alberto Valenzuela-Palomo, Beatriz Díez-Gómez, Mar Infante, Mercedes Durán, Germán Marcos, Enrique Lastra, Susana Gómez-Barrero, Eladio A Velasco
PURPOSE: Promoter mutations may affect transcription and can be associated with human diseases. However, the promoters of the breast cancer (BC) genes are not regularly screened. Our goal was to investigate the BRCA2 promoter in order to study a possible correlation between impaired transcription and disease. METHODS: The proximal and core promoter of the BRCA2 gene was sequenced in 95 high-risk BC patients. A BRCA2-promoter insert [- 938 to + 312 from the transcription start site (TSS)] was generated and cloned into the firefly luciferase vector pGL4...
May 15, 2018: Breast Cancer Research and Treatment
https://www.readbyqxmd.com/read/29766236/ethnicity-specific-impact-of-hla-i-ii-genotypes-on-the-risk-of-inhibitor-development-data-from-korean-patients-with-severe-hemophilia-a
#19
Hyun-Young Kim, Jin-Hee Cho, Hee-Jung Kim, Hae-Sun Chung, Sun-Hee Kim, Ki-O Lee, Soo-Young Jung, Ki-Young Yoo, Hee-Jin Kim
Inhibitor development is the most serious complication in patients with hemophilia. We investigated association of HLA genotypes with inhibitor development in Korean patients with severe hemophilia A (HA). HLA genotyping was done in 100 patients with severe HA including 27 patients with inhibitors. The allele frequencies between inhibitor-positive and inhibitor-negative patients were compared. HLA class I alleles were not associated with the inhibitor status. In HLA class II, DRB1*15 [n = 100, odds ratio (OR) 0...
May 16, 2018: Annals of Hematology
https://www.readbyqxmd.com/read/29766047/a-transient-dopamine-signal-represents-avoidance-value-and-causally-influences-the-demand-to-avoid
#20
Katherine J Pultorak, Scott A Schelp, Dominic P Isaacs, Gregory Krzystyniak, Erik B Oleson
While an extensive literature supports the notion that mesocorticolimbic dopamine plays a role in negative reinforcement, recent evidence suggests that dopamine exclusively encodes the value of positive reinforcement. In the present study, we employed a behavioral economics approach to investigate whether dopamine plays a role in the valuation of negative reinforcement. Using rats as subjects, we first applied fast-scan cyclic voltammetry (FSCV) to determine that dopamine concentration decreases with the number of lever presses required to avoid electrical footshock (i...
March 2018: ENeuro
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