Conditioned Reinforcement Research Articles

Pairs of rats cooperate more when responding to simultaneous reinforcement than to alternated reinforcement.

The purpose of this experiment was to explore whether simultaneous access to consequences configures a defining functional feature of coordination. We evaluated whether coordination episodes are maintained when reinforcers are alternately presented to two cooperating rats across these episodes, in contrast to the delivery of reinforcers simultaneously for both rats and independently for each rat. Rat pairs responded under either a tandem fixed-interval (FI) 10-s FI 10-s or a tandem variable-interval (VI) 10-s VI 10-s schedules. In the baseline, lever presses of each rat were individually reinforced according to the tandem FI FI schedule. In two simultaneous reinforcement conditions, reinforcer deliveries depended on coordination episodes under either tandem schedule. In two alternated reinforcement conditions, rats accessed reinforcers in alternation under either tandem schedule. Two main findings are reported: (1) proportions of coordination were consistently higher under the simultaneous than under the alternated reinforcement condition regardless of the type of tandem schedules (FI or VI) and (2) proportions of coordination were similar in the individual and alternated reinforcement conditions. Although the obtained reinforcement rates limit a conclusive evaluation, these findings indicate that the simultaneous delivery of reinforcers (mutual reinforcement) is a critical variable in the operant selection of coordinated responding.

Anti-seepage reinforcement property and pollution control effect of bio-cemented fracture zone in electrolytic manganese residue dump

The heavy metal (HM) pollutants in electrolytic manganese residue (EMR) can easily diffuse through the seepage channel of the dump under the leaching action of rainfall. Particularly, the fracture zone, as one of the widely distributed seepage channels in the manganese residue dump (MRD), poses a greater threat to the ecological environment due to its weak mechanical properties, strong ductility, and numerous fractures. In this study, the microbially induced calcium carbonate precipitation (MICP) method was used for anti-seepage reinforcement of the fracture zone in an MRD to be constructed. The optimal conditions for the anti-seepage reinforcement of the fracture zone using the MICP method were proposed, and the control effect of the bio-cemented fracture zone on the major HM pollutant in the leachate of EMR was illustrated. Results showed that after grouting at a rate of 3 mL/min for 12 cycles with a grouting slurry of high urease activity (9 mM urea/min) and high cementation solution concentration (1.5 mol/L), the permeability coefficient of the fracture zone decreased from 10−4 to 10−5, and the unconfined compressive strength was approximately 5.58 times that of uncemented. Furthermore, the cubic calcite crystal clusters with high purity, good stability, dense arrangement, and high cementation properties were generated using the optimal conditions, and the pores were transformed from long columnar to spherical pores. Additionally, the Mn2+ concentration in the effluent from the fracture zone at the stabilization stage was only 663 mg/L, significantly lower than that of the leachate of EMR, and the risk of leaching changed from very high risk to low risk. The research outcomes can provide guidance and reference for laboratory model testing and in-situ testing of bio-cemented fracture zone, and it is expected to provide the theoretical and technological support for green and economic anti-seepage reinforcement of the fracture zone.

Frontostriatal connectivity dynamically modulates the adaptation to environmental volatility.

Humans adjust their learning strategies in changing environments by estimating the volatility of the reinforcement conditions. Here, we examine how volatility affects learning and the underlying functional brain organizations using a probabilistic reward reversal learning task. We found that the order of states was critically important; participants adjusted learning rate going from volatile to stable, but not from stable to volatile, environments. Subjective volatility of the environment was encoded in the striatal reward system and its dynamic connections with the prefrontal control system. Flexibility, which captures the dynamic changes of network modularity in the brain, was higher in the environmental transition from volatile to stable than from stable to volatile. These findings suggest that behavioral adaptations and dynamic brain organizations in transitions between stable and volatile environments are asymmetric, providing critical insights into the way that people adapt to changing environments.

On the prevalence and magnitude of resurgence during delay-and-denial tolerance teaching.

Resurgence is the recurrence of target behavior (e.g., challenging behavior) during a worsening of reinforcement conditions (e.g., increases in response effort, decreases in alternative reinforcement). Previous studies have examined the prevalence and magnitude of resurgence during functional communication training implemented with discriminative stimuli. We conducted a systematic review of the literature to analyze the magnitude and prevalence of resurgence during delay-and-denial tolerance teaching. Similar to previous studies with discriminative stimuli, resurgence occurred for most participants and in about one third of transitions. When resurgence was present, challenging behavior increased to approximately 26% of baseline levels. Resurgence was less likely to occur during response-effort manipulations (i.e., complexity teaching, tolerance-response teaching) and was most likely to occur during increases in delays that ended following the passage of time rather than a response criterion. We discuss implications for treatment refinements and future treatment-relapse research.

Fractionating impulsivity and reward-related phenotypes in adolescent mice.

Adolescence is a developmental period characterized by changes in the brain and behavior, including heightened reward seeking, increased impulsivity, and elevated risk-taking behavior. It is also a sensitive period for the development of a number of behavioral and psychiatric disorders associated with pathological phenotypes of reward processing and impulsivity. Landmark human studies are charting the development of impulsivity and other reward-related phenotypes to identify the facets and timecourse of the adolescent phenotype. Collecting similar data from mice is important to enable molecular, cellular, and circuit-level interrogation of adolescent maturation of reward, motivation, and impulsive behavior. These complex phenotypes have traditionally been difficult to assay in adolescent mice. Here, using a combination of approaches including homecage testing, we tested a number of facets of reward seeking, impulsivity, motivation, and incentive salience attribution during adolescent development. We found that adolescent mice show increased reward seeking, impulsive action, and motivation. Interestingly, we found no effect of adolescence on impulsive choice, sign-tracking, reward-learning, or conditioned reinforcement. Overall, our studies set the stage for approaches to study multi-faceted phenotypes related to impulsivity and other reward-related behaviors in adolescent mice to examine the developmental trajectories of brain and behavior.

NUMERICAL INVESTIGATION OF TORSIONAL BEHAVIOUR OF REINFORCED CONCRETE ELEMENTS WITH DIFFERENT SECTION SHAPES

When torsional cracks occur in the RC element as a result of torsion effects occurring in the structure, the cross-section stiffness decreases by 1/10-1/30 of the stiffness before cracking. When the design codes are examined, it is seen that the reinforced concrete design under the effect of torsion is not sufficiently emphasized. In the study, it is aimed to determine the cross-sectional properties of reinforced concrete elements that will be exposed to torsion effects in accordance with the behavior of the RC element. In this study, reinforced concrete elements with circular, square and rectangular cross-section shapes were modeled in accordance with the cross-section and reinforcement conditions specified in TEC-2007 and analyzed by ANSYS program. The torsional capacities of the elements increase as the cross-sectional area increases. Circular sections exhibit a highly ductile behavior in terms of rotation. Rectangular sections have more stiffness than circular and square sections to torsion.

RDS04-010: A novel atypical DAT inhibitor that inhibits cocaine taking and seeking and itself has low abuse potential in experimental animals.

Cocaine use disorder (CUD) is a severe public health problem, and currently, there is no FDA-approved medication for its treatment. Atypical dopamine (DA) transporter (DAT) inhibitors display low addictive liability by themselves and may have therapeutic potential for treatment of psychostimulant use disorders. Here, we report that RDS04-010, a novel atypical DAT inhibitor that binds to an inward-facing conformation of DAT due to its sulfoxide moiety, displayed distinct pharmacological profiles in animal models of addiction from its sulfide analog, RDS03-094, a DAT inhibitor that binds to a more outward-facing conformation. Systemic administration of RDS04-010 dose-dependently inhibited cocaine self-administration (SA), shifted the cocaine SA dose-response curve downward, decreased motivation for cocaine seeking under progressive ratio reinforcement conditions, and inhibited cocaine-primed reinstatement of drug-seeking behavior. RDS04-010 alone neither altered optical brain-stimulation reward nor evoked reinstatement of drug-seeking behavior. RDS04-010 substitution for cocaine was not able to maintain self-administration in rats trained to self-administer cocaine. In contrast, RDS03-094 displayed more cocaine-like reinforcing effects. Its pretreatment upward-shifted both the cocaine self-administration dose-response and optical brain-stimulation reward curves. RDS03-094 alone was able to reinstate extinguished cocaine-seeking behavior and sustain self-administration during a substitution test. Collectively, these findings suggest that RDS04-010 is a novel atypical DAT inhibitor with favorable therapeutic potential in reducing cocaine-taking and -seeking behavior with low addictive liability. Moreover, this extensive behavioral evaluation further confirms the role DAT binding conformation plays in the distinctive profiles of atypical DAT inhibitors that prefer the inward facing conformation.

Resurgence in a discrete-trial procedure in rats.

Resurgence is a transient recovery of a previously extinguished target response following a worsening of reinforcement conditions for an alternative response. Laboratory studies with nonhuman animals typically assess resurgence in free-operant situations where subjects can freely emit responses. The purpose of the current study was to investigate whether resurgence would be observed in a discrete-trial procedure where only a single response could occur in each trial, using rats as subjects. The experiment consisted of three phases, and each session ended after 200 trials. All trials began with the insertion of target and alternative levers and ended once a response was emitted. In Phase 1, both target and alternative responses were reinforced with a probability of .25. In Phase 2, the target response was extinguished while still reinforcing the alternative response with a probability of .25. Finally, resurgence was tested by placing the alternative response on extinction. All rats showed robust resurgence in this highly constrained discrete-trial situation. We also found that the latencies of resurged target responses differed from those in Phase 1. Overall, the present discrete-trial procedure could produce reliable resurgence as with typical free-operant procedures and has several potential benefits for studying resurgence.

Peridynamics simulations of the damage of reinforced concrete structures under radial blasting

Concrete is prone to damage under explosive loads, which can cause a large number of casualties and property losses. The concrete fragmentation process during explosion is transient and dynamic, and the experimental measurement of such events is difficult and risky to conduct, and the intermediate explosion process is difficult to observe in the experimental tests. Therefore, the numerical simulation is an ideal method to model and simulate the explosion process of concrete. Different from the traditional finite element method, Peridynamics (PD) method uses the spatial integral equation to replace the traditional local differential equation to solve the fragmentation problem with massive and complex discontinuous patterns. In this study, a peridynamics (PD) model is developed to simulate the failure process of reinforced concrete (RC) structures under radial blasting. Concrete PD models with different cavity sizes and reinforcement conditions were established and calibrated with the experimental data. We find that the crack growth and damage pattern obtained in the peridynamics simulation is consistent with the experiment test results, which verifies the feasibility of peridynamics method as a modeling tool for modeling concrete damage under explosive load and for evaluating anti-explosion performance of RC concrete structures.

Moral stories reading with internal negative reinforcement enhance children’s sharing behavior

ABSTRACT Reading moral stories is crucial for children’s moral learning and development. The present study examined the effect of features of moral stories on children’s sharing behavior. Experiment 1 which involved 153 4-year-old children and 169 6-year-old children, utilized a 2 × 2 design to examine the effect of story value of reinforcement (positive vs. negative) and source of reinforcement (internal vs. external) in stories on children’s sharing behavior of 4-year-old and 6-year-old children. Our findings indicate a notable effect of internally driven negative reinforcement on sharing behaviors among 6-year-olds, particularly when the narrative prompted a feeling of guilt within the protagonist for not sharing. However, there was no significant difference in 4-year-olds. Experiment 2 considered the children’s reflection on the consequences of their actions, involved 131 6-year-old children and compared three conditions (moral stories with internal negative reinforcement, moral dilemma stories, and controlling conditions). The results showed that children in internal negative reinforcement condition exhibited more sharing behavior. In contrast, no significant differences were found between moral dilemma stories and controlling conditions. These findings highlight that feeling guilt can promote prosocial behavior among 6-year-old children.

Detection of concrete reinforcement condition based on Decay Time Constant

Abstract Reinforced concrete (RC) is widely used in all kinds of building facilities and electric power infrastructure. When its internal reinforcement structure is unreasonable or the quality of reinforcement is not up to standard, the performance of RC will be greatly reduced, resulting in a huge safety hazard. In this paper, a non-destructive testing method based on pulsed eddy current (PEC) for the state of internal reinforcement in concrete is proposed with concrete poles as the research object. The relationship between PEC response and the multiple parameters of the reinforcement has been analyzed, the decay time constant (DTC) is obtained, and a simulation model is built to demonstrate the connection between the DTC and the electrical conductivity, relative magnetic permeability, and thickness. Finally, a simulation model is constructed to verify the effectiveness of the proposed method for rebar condition detection.

Sustainable lignocellulosic mediterranean biocomposites: Thermogravimetric analysis, mechanical performance, morphological and comparative study

Utilizing accessible agricultural waste to create sustainable materials is a potentially beneficial attempt toward developing better bio-products and a more sustainable socioeconomic environment. Accordingly, this work aims to investigate the mechanical performance enhancement and/or deteriorations as well as morphological and thermal characteristics of certain Mediterranean lignocellulosic fiber composites considering various reinforcement conditions. Several composites of polypropylene pomegranate peel powder (PG) and short corn leaves (CL) were designed and fabricated with various reinforcement conditions to demonstrate their potential characteristics. Moreover, the experimental results of this work were compared with commonly used fiber/PP composites worldwide to demonstrate their appropriateness for producing bio-based composites suitable for various applications. The investigations included determining the tensile strength, tensile modulus, elongations at break properties under various reinforcement conditions, as well as revealing the thermal properties of the fibers to expose their suitability for such bio-based composites to improve utilizing such available waste of fibers into useful materials for various mechanical components. Thermal gravimetric analysis (TGA) and derivative thermal gravimetric analysis (DTG) were also carried out to examine thermal stability and to distinguish the maximum degradation temperature (Tmax) of the cellulosic fiber compositions. The outcomes revealed that both types of fibers, pomegranate peel powder and short corn leaves, had positive impacts on the tensile strength and modulus of PP regardless of the weight percentage. The 40 wt% of corn leaves displayed the best improvement in the strength (+29 %) and modulus (+17 %). The 40 wt%, CL-PP reached tensile modulus of 1589.5 MPa, whereas the best modulus for the PG-PP was 1399.4 MPa at 30 wt%. When comparing the tensile strength and modulus of PG/PP and CL/PP composites with those reported in the literature, these composites demonstrated superior tensile properties relative to thirteen other types documented. Regarding the thermal analysis, PG and CL fibers could withstand the processing temperature without degradation, which enables them to be feasibly utilized in bio-based composites to enhance the development of green bio-products. When it comes to the morphological analysis, it was observed that there was a good adhesion between PP and CL, which interprets the enhancement tensile properties.

Testing the predictions of reinforcement: long-term empirical data from a damselfly mottled hybrid zone.

Theoretical work suggests that reinforcement can cause the strengthening of prezygotic isolation in sympatry by mitigating the costs of maladaptive hybridization. However, only a handful of studies have simultaneously tested multiple predictions of this theory in natural populations. We investigated reinforcement in a mottled hybrid zone between the damselflies Ischnura elegans and I. graellsii, which are characterized by incomplete and asymmetric reproductive isolation and exhibit reproductive character displacement in mating-related structures. We tested the conditions for reinforcement by quantifying whether hybridization was costly and prezygotic isolation stronger in sympatry compared with allopatry. Additionally, we investigated two specific predictions of reinforcement: i) greater premating asymmetries in sympatry; and ii) weaker postzygotic isolation in sympatry than in allopatry. Our findings indicate the presence of maladaptive hybrids, which suggests Bateson-Dobzhansky-Müller incompatibilities in allopatry. We also found that reinforcement has strengthened mechanical isolation, at least in one direction in sympatry. We observed evidence for greater premating asymmetries in sympatry than in allopatry, which is consistent with reinforcement. However, fully testing the prediction of weaker postzygotic isolation in sympatry compared to allopatry was hindered by the highly asymmetrical levels of reproductive isolation between the two reciprocal cross directions. Our study highlights a case where reinforcement and heterospecific gene flow exert opposite effects on reproductive isolation between reciprocal crosses, where reinforcement increases reproductive isolation in one direction while gene flow weakens it in the opposite direction.

Influential reinforcement parameters, elemental mapping, topological analysis and mechanical performance of lignocellulosic date palm/epoxy composites for improved sustainable materials

The value of biomaterials for green products has begun to develop more ecofriendly and renewable sustainable materials for a better circular economy and to reduce carbon footprints. This work presents integrated investigations of the lignocellulosic date palm/epoxy composites at various reinforcement condition parameters for sustainable structural materials where elemental mapping, topological analysis, and mechanical performance have been performed. Mapping energy dispersive X-ray spectroscopy was utilized to assess the composite composition properly. Elemental mapping and a scanning electron microscope were employed to evaluate the chemical composition of the composites. The mechanical performance of the produced composites was also explored in terms of ultimate tensile strength, tensile modulus, elongation at break, and impact energy properties. The effects of fiber loading, fiber length, and fiber width (as long fiber, short fiber, and long-thin fiber) were investigated for the date palm fiber/epoxy composites. Results have revealed that the composite behavior was affected by several influential reinforcement parameters. The energy dispersive X-ray spectroscopy maps by C–K, O–K, Si–K, K-K, and Ca-K demonstrated that the composites contain mainly carbon, silicon, and oxygen. It was evident that the modulus of elasticity property of short fiber composites exhibits an increasing trend with higher fiber content, even at 35 wt%. Moreover, the enhancement of tensile strength for the short fiber size composites reached 72.5 %. However, such tensile strength of thin fiber size/epoxy composites achieved 135.7 % at 25 wt% indicating superior development of this mechanical property. The long date palm fiber composites demonstrated the best value of modulus of elasticity and the maximum impact energy of 15.3 kJ/m2 attained at 25 wt%, which is about 112.5 % enhancement. Scan electron microscope was capable of confirming that broken fibers were not separated from the matrix indicating the good adhesion between the fiber and the matrix that supports their good mechanical performance.

Experimental study on the effect of freeze–thaw cycles to the cohesion and moisture content of geogrid reinforced silty clay

The freezing and thawing cycle is one of the primary causes of damage and instability to buildings in seasonal frost regions. During this process, the mechanical properties of soil are affected, leading to settlement, cracking, or deformation of infrastructure. Mitigating or reducing the occurrence of building frost damage in seasonal frost regions has become an important subject of study. Freeze–thaw (F–T) action will influence the distribution of moisture inside the reinforced soil and change the strength of thawing soil, which is closely related to the main influencing factors, such as initial moisture content, compaction degree, reinforced spacing, number of freeze–thaw cycles (FTC), freezing temperature, and effective vertical stress. Cohesion is an important index to determine the shear strength of clay, which is important to analyze the change in cohesion after F–T. Meanwhile, cohesion is closely related to soil moisture content. This study conducted orthogonal experiments on these primary influencing factors (6 factors at 5 levels) through FTC tests, triaxial tests, and moisture content tests to determine the undrained cohesion and moisture content of the clay after FTC, thereby establishing the influence of reinforcement on soil strength under freeze–thaw conditions. Based on the experimental results, SPSS software was used to fit the regression equations of undrained cohesion and moisture content expressed by the main influencing factors at different heights of the clay. Optimization options for the main influencing factors were obtained with Matlab software when the highest undrained cohesion values 6.8, 10.6, 8.9 kPa and lowest moisture content values 24.0%, 24.3%, 26.2% appeared in upper, middle and lower parts of the testing clay structure respectively, in conditions of − 15 °C freezing temperature and 5 times FTC. And determined the optimal combinations of moisture content, reinforcement spacing, compaction density, and vertical load at different heights. Decreasing reinforced spacing in silty clay was beneficial for liquid underwater seepage after F–T. The redistribution of internal moisture in the soil sample strengthened its undrained cohesion, thereby increasing the soil's shear strength. Comparing reinforcement conditions at different locations, it was found that when there were 3 layers of reinforcement with a spacing of 150 mm between them, this spacing was optimal. It played a significant role in improving the soil's shear strength and enhancing its bearing capacity. For reinforced clay itself, the order of the main factors influencing the undrained cohesion of soil after F–T, from high to low, was initial moisture content, reinforced spacing, and compaction degree.

Meaningful gazes: Conditioned reinforcement for following gaze as a prerequisite for joint attention

AbstractJoint attention is an important developmental skill. This series of studies investigated the teaching of component joint attention skills to 10 children with autism ranging in age from three to five years. The goal was to teach gaze shifting within a joint attention interaction. An additional goal was to expand some participants' community of reinforcers to include social reinforcers. Each study employed a single‐case research design using design variations for one dependent variable: gaze shifting. All 10 children improved their ability to shift their gaze to a therapist. Four participants demonstrated acquisition of social reinforcers.

Memristor-Based Neural Network Circuit of Operant Conditioning With Bridging and Conditional Reinforcement

Memristor-Based Neural Network Circuit of Operant Conditioning With Bridging and Conditional Reinforcement

Numerical modelling of flexural performance of textile reinforced mortar strengthened concrete beams

In recent years, the application of textile reinforced mortar (TRM) as an overlay has become an important method for repairing and strengthening old masonry structures. However, the quantitative analysis and design of TRM-strengthened reinforced concrete (RC) beams are still limited. To address this gap, a nonlinear finite element (FE) model is proposed in this study to simulate the flexural behavior of TRM-strengthened RC beams. The developed model is validated using experimental results and subsequently utilized for the design of TRM-strengthened RC beams. Various TRM design parameters, including the number of textile layers, textile longitudinal length, and textile mesh size, are parametrically investigated. The modelling results reveal that increasing the number of textile layers and longitudinal length while decreasing the textile mesh size can enhance the bending strength of TRM-strengthened RC beams. Furthermore, an analytical model is proposed to predict the flexural strength of TRM-strengthened RC beams, facilitating rapid strength estimation of TRM-strengthened RC beams. The predicted results demonstrate good agreement with the numerical simulation results. The established FE models can predict the bending performance of TRM-strengthened RC beams under different reinforcement conditions, and the simulation outcomes can provide valuable guidance for their design.

The Investigation of Stability on Slopes Utilizing Reinforcement Gabion Walls and Concrete Piles for Mitigating Landslide Disasters

Introduction Landslides frequently occur along roads crossing mountainous terrain during the rainy season, posing a significant risk of severe disruption to land transportation routes. Efficient and accurate resolutions are essential in managing landslides to facilitate immediate transportation recovery, such as gabion walls and pile installation. Aim This article aimed to evaluate the effect of installing gabions and piles for safety measures on the stability of slope landslides. The analysis of slope stability was performed utilizing the Plaxis 2D software. For reinforced slopes, the Safety Factor (SF) value utilized as a benchmark for evaluating slope stability was SF ≥ 1.5. Methods An assessment of the stability of the slope was conducted under three conditions: its original state, after reinforcement with gabions, and after the integration of gabions with mini piles. The dimensions of the gabion setting, as determined by the L-W-H notation (length-width- height), were 2 m x 1m x 0.5 m and 1 m x 2 m x 0.5 m. The pile was designed to be 2.5 m long at the gabion's end. The analysis was conducted at 45°, 60°, 70°, and 90° slopes. Results Based on the results of slope stability calculations, an SF = 1.11 was determined under no reinforcement conditions. By applying reinforced gabion walls measuring 2 m in width combined with mini piles at a 45° slope, the best SF was achieved, which was 2.58. Conclusion Given the comparable topographical circumstances, it is expected that the outcomes of this analysis on slope stability will be applicable in mitigating the occurrence of landslides.

A systematic review of procedures for establishing conditioned reinforcers

AbstractEstablishing conditioned reinforcers is often critical to treatment for individuals diagnosed with autism spectrum disorder or intellectual and developmental disabilities (IDDs). Although researchers have evaluated several procedures, methods and results vary across studies, making it difficult to draw conclusions about these procedures' general and relative effectiveness. The purpose of this systematic review was to assess the overall and relative effectiveness of stimulus‐stimulus (S‐S) pairing, response‐stimulus (R‐S) pairing, and operant discrimination training (ODT) for establishing conditioned reinforcers for children on the autism spectrum or who have an IDD. Thirty‐one studies, including 12 theses and dissertations, met inclusion criteria. Eight studies evaluated S‐S pairing, 20 evaluated R‐S pairing, and nine evaluated ODT. Combined, S‐S pairing, R‐S pairing, and ODT were effective at establishing conditioned reinforcers in only half of all attempts. However, analysis indicated that R‐S pairing is the most effective procedure, followed by S‐S pairing and ODT, in that order.