Effects of Associatively Significant Posttrial Stimuli on Learning and Memory

1985 ◽  
Vol 37 (2b) ◽  
pp. 101-119
Author(s):  
Ruth M. Colwill

Pigeons were trained on a delayed conditional discrimination in which the choice between two simultaneously presented stimuli depended on how the trial started. Choice of one of the stimuli was reinforced if the trial had been initiated by presentation of a food sample and choice of the other was reinforced if no sample had been presented. Subsequently, test trials were administered on which an associatively significant stimulus was presented during the retention interval. This manipulation was intended to modulate the short-term retention of information about the food sample. It was found that performance on food sample test trials was enhanced by presentation of an excitor for food, disrupted by presentation of an inhibitor for food and unaffected by presentation of an associatively neutral stimulus. The impact of these posttrial stimuli was also assessed on the ability of the food sample to serve as a reinforcer. This was done by recording the development of responding to a keylight that signalled the food sample on these test trials. Compared to the associatively neutral stimulus, both the excitor and the inhibitor interfered with the development of keypecking. These results are discussed with regard to the issue of how posttrial events modulate associative learning.

1975 ◽  
Vol 27 (1) ◽  
pp. 47-62 ◽  
Author(s):  
M. T. Turvey ◽  
Robert A. Weeks

Under the conditions of the distractor paradigm, short-term retention declines to a minimum in a very brief period. The rapid forgetting can be said to reflect the declining contribution of the short-term store or primary memory and the asymptote can be taken as a measure of the contribution of the long-term store or secondary memory. It was shown that manipulating proactive effects by varying the recency of prior material affected only the primary memory component of the short-term retention function. On the other hand manipulating the difficulty of the subsidiary task performed during the retention period with proactive effects held constant affected both the primary and the secondary components. The results were discussed with respect to the relation between the two memory components and the idea that proactive effects are limited to long-term store.


2017 ◽  
Vol 60 (6S) ◽  
pp. 1712-1725 ◽  
Author(s):  
Mara Steinberg Lowe ◽  
Adam Buchwald

Purpose This study investigated whether whole nonword accuracy, phoneme accuracy, and acoustic duration measures were influenced by the amount of feedback speakers without impairment received during a novel speech motor learning task. Method Thirty-two native English speakers completed a nonword production task across 3 time points: practice, short-term retention, and long-term retention. During practice, participants received knowledge of results feedback according to a randomly assigned schedule (100%, 50%, 20%, or 0%). Changes in nonword accuracy, phoneme accuracy, nonword duration, and initial-cluster duration were compared among feedback groups, sessions, and stimulus properties. Results All participants improved phoneme and whole nonword accuracy at short-term and long-term retention time points. Participants also refined productions of nonwords, as indicated by a decrease in nonword duration across sessions. The 50% group exhibited the largest reduction in duration between practice and long-term retention for nonwords with native and nonnative clusters. Conclusions All speakers, regardless of feedback schedule, learned new speech motor behaviors quickly with a high degree of accuracy and refined their speech motor skills for perceptually accurate productions. Acoustic measurements may capture more subtle, subperceptual changes that may occur during speech motor learning. Supplemental Materials https://doi.org/10.23641/asha.5116324


2020 ◽  
Vol 5 (21) ◽  
pp. 220-227
Author(s):  
Rohana Abdul Rahman

The impact of Coronavirus disease has transcended beyond imaginable. Everyone is vulnerable and no one on this planet can safely say that he or she is protected against the deadly virus. All governments are taking immediate steps to address the ensuing repercussion of the pandemic, both on a short-term and long-term basis. Malaysia has passed a law that provides for temporary measures to reduce the impact of COVID-19 on the general economic sectors affecting the general economic well-being of the country. This paper explains the provisions of the COVID-19 Act 2020 and the specific other laws that it intends to modify therein. In particular, the paper highlights the establishment of a mediation process in respect of disputes arising from the inability to perform contractual obligations by parties during the pandemic. The paper concurs that COVID-19 Act 2020 attempts to cover quite comprehensive temporary measures to address issues relating to the pandemic and in the process provides validity to the actions taken by various parties before its commencement. On the other hand, the paper argues that several vague and uncertain provisions of the law led to questionable application and implication thus creating doubts as to its effectiveness.


2021 ◽  
pp. bmjsrh-2021-201168
Author(s):  
Emma Rezel-Potts ◽  
Melissa J Palmer ◽  
Caroline J Free ◽  
Hannah McCulloch ◽  
Paula Baraitser

BackgroundOnline contraception services increasingly provide information, clinical assessment and home-delivered oral contraceptives (OCs). Evidence is lacking on the effects of online contraceptive service use on short-term contraceptive continuation.MethodsCohort study comparing contraceptive continuation between new users of a free-to-access online OC service in South East London with those from other, face-to-face services in the same area. Online questionnaires collected data on participants’ sociodemographic characteristics, motivations for OC access, service ratings, OC knowledge and contraceptive use. Contraceptive use in the 4-month study period was measured using health service records. Unadjusted and multivariable logistic regression models compared outcomes between the online service group and those using other services.ResultsOnline service-users (n=138) were more likely to experience short-term continuation of OCs compared with participants using other services (n=98) after adjusting for sociodemographic and other characteristics (adjusted OR 2.94, 95% CI 1.52 to 5.70). Online service-users rated their service more highly (mean 25.22, SD 3.77) than the other services group (mean 22.70, SD 4.35; p<0.001), valuing convenience and speed of access. Among progestogen-only pill users, knowledge scores were higher for the online group (mean 4.83, SD 1.90) than the other services group (mean 3.87, SD 1.73; p=0.007). Among combined oral contraceptive users, knowledge scores were similar between groups.ConclusionsFree-to-access, online contraception has the potential to improve short-term continuation of OCs. Further research using a larger study population and analysis of longer-term outcomes are required to understand the impact of online services on unintended pregnancy.


Author(s):  
Yaping Wang ◽  
Nusrat Yussouf ◽  
Edward R. Mansell ◽  
Brian C. Matilla ◽  
Rong Kong ◽  
...  

AbstractThe Geostationary Operational Environmental Satellite-R (GOES-R) Geostationary Lightning Mapper (GLM) instrument detects total lightning rate at high temporal and spatial resolution over the Americas and adjacent oceanic regions. The GLM observations provide detection and monitoring of deep electrified convection. This study explores the impact of assimilating the GLM derived flash extent density (FED) on the analyses and short-term forecasts of two severe weather events into an experimental Warn-on-Forecast system (WoFS) using the Ensemble Kalman Filter data assimilation technique. Sensitivity experiments are conducted using two tornadic severe storm events, one with a line of individual supercells and the other one with both isolated cells and a severe convective line. The control experiment (CTRL) assimilates conventional surface observations and geostationary satellite cloud water path into WoFS. Additional experiments also assimilate either GLM FED or radar data (RAD), or a combination of both (RAD+GLM). It is found that assimilating GLM data in the absence of radar data into the WoFS improves the short-term forecast skill over CTRL in one case, while in the other case degrades the forecast skill by generating weaker cold pools and overly suppressing convection, mainly owing to assimilating zero FED values in the trailing stratiform regions. Assimilating unexpectedly low FED values in some regions due to low GLM detection efficiency also accounts for the poorer forecasts. Although RAD provides superior forecasts over GLM, the combination RAD+GLM shows further gains in both cases. Additional observation operators should consider different storm types and GLM detection efficiency.


2014 ◽  
Vol 62 (1) ◽  
pp. 24-32 ◽  
Author(s):  
Elena Szolgayová ◽  
Josef Arlt ◽  
Günter Blöschl ◽  
Ján Szolgay

Abstract Short term streamflow forecasting is important for operational control and risk management in hydrology. Despite a wide range of models available, the impact of long range dependence is often neglected when considering short term forecasting. In this paper, the forecasting performance of a new model combining a long range dependent autoregressive fractionally integrated moving average (ARFIMA) model with a wavelet transform used as a method of deseasonalization is examined. It is analysed, whether applying wavelets in order to model the seasonal component in a hydrological time series, is an alternative to moving average deseasonalization in combination with an ARFIMA model. The one-to-ten-steps-ahead forecasting performance of this model is compared with two other models, an ARFIMA model with moving average deseasonalization, and a multiresolution wavelet based model. All models are applied to a time series of mean daily discharge exhibiting long range dependence. For one and two day forecasting horizons, the combined wavelet - ARFIMA approach shows a similar performance as the other models tested. However, for longer forecasting horizons, the wavelet deseasonalization - ARFIMA combination outperforms the other two models. The results show that the wavelets provide an attractive alternative to the moving average deseasonalization.


2003 ◽  
Vol 30 (4) ◽  
pp. 321 ◽  
Author(s):  
Ian Abbott ◽  
Amanda Mellican ◽  
Michael D. Craig ◽  
Matthew Williams ◽  
Graeme Liddelow ◽  
...  

In 1985 new silvicultural prescriptions for managing jarrah (Eucalyptus marginata) forest in south-west Western Australia came into operation. The most extreme logging treatment (gap release) involved removal of most of the overstorey from patches no larger than 10 ha, followed by a regeneration fire. In the other logging treatment (shelterwood), less wood was removed from a larger area, also followed by a fire. This study examined the impact of these disturbances on the avifauna by monitoring species richness and abundance of birds one year before logging, one year before burning, and for five years after burning. Although 68 bird species were recorded during the seven years of the study, 29 of these were detected fewer than 15 times. Of the other 39 bird species recorded, only two (Gerygone fusca and Acanthiza apicalis) showed a statistically significant treatment effect over time on their abundance. The abundance of G. fusca initially declined in the disturbed treatments and by Year 7 of the study (5 years post-fire) in the gap-release treatment had not recovered its original abundance. A. apicalis increased its abundance in both shelterwood and gap-release treatments. By Year 7, both species in the logged treatments had abundances similar to those in the unlogged treatments. Total abundance of all species varied little across treatments. Species richness was highest by Year 7 in the shelterwood and lowest in the gap-release treatment. In some years community structure varied more at the external-reference sites (not recently logged or burnt) than at the gap-release sites. In particular, there was little overlap in community structure in the external-reference treatment between the first and final years, whereas the pre-logging and final year in the gap-release treatment showed a high degree of overlap. These differences are suggestive of overriding short-term annual variation in broad-scale factors rather than local factors. Yearly variation in rainfall and temperature was documented; during low rainfall periods, populations of foliage arthropods may have been reduced.


Author(s):  
Dr. Saleh Salman Omairi ◽  
Prof. Hussein Adnan Mohammed

We hear about fatty liver more and more often: at least one European adult in five suffers from it and pediatric cases are also on the rise, a consequence of childhood obesity of epidemic proportions in recent years. The cause is metabolic : liver cells normally combine free fatty acids in the blood - introduced with the diet and produced by metabolism - with sugars, giving rise to complex lipids such as triglycerides, which can be accumulated in the liver for storage and energy reserve and to be exploited if necessary. Overweight, dyslipidemia, diabetes, bowel disease or abuse of certain medications (like cortisones) can increase the workload on the liver which is thus storing more fat than necessary. Feeling nervous when stressed is completely natural. This is a short-term stress sign. Chronic stress, on the other hand, is characterized by prolonged symptoms, including breathing difficulties, dizziness, decreased desire, chest pains and fatigue. Many of these symptoms are immediately identifiable by the sufferer. However, the impact of stress is not only visible externally. Inside, our bodies desperately struggle to restore a natural balance. This chemical disruption caused by chronic stress affects many other biological features. This article highlights the effect of stress on fatty liver.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 42-42
Author(s):  
Arielle L Langer ◽  
Adam Binder ◽  
Eileen Scigliano

Background: The goal of medical school hematology preclinical curricula is to prepare students not only for course exams and standardized testing but also clinical care during clerkships and beyond. While active teaching methods such as team-based learning (TBL) are associated with improved end of course exam performance, the impact on long-term retention has not been evaluated. Methods: We assessed the impact of three different teaching approaches on short term understanding and long-term retention of hematology knowledge after a hematology pathophysiology course. Lecture material was reinforced with traditional case-based small group discussion, TBL, or no small group reinforcement. Knowledge assessments with 15 multiple choice questions were conducted prior to the course, immediately after course, and 14 months after the course at the end of the core clerkship year. Several topics covered by traditional small groups in the 2018 were switched to TBL in the 2019, and, thus, could be directly compared across the two cohorts. Results: We recruited 70 students, 34 from the 2018 iteration of the course and 36 from the 2019, which represents 24% of eligible students. Of these, 48 students completed the final assessment (69% retention). Prior to the course, students answered 31% of questions correctly. This increased to 78% immediately after the course with significant differences across teaching methods: TBL 87%; traditional small group 78%; no small group 76% (p&lt; 0.01). Overall knowledge declined to 70% at long-term follow up. The effect of the teaching method also dissipated and was no longer statistically significant: TBL 75%; traditional small group 67%; no small group 70%. When restricted to three topics converted from traditional small group in 2018 to TBL in 2019, the long-term benefit was not shown, with correct answers in 59% of the 2018 cohort taught through traditional small groups and 54% of the 2019 cohort taught through TBL. Long-term retention did not vary according to whether students reported re-exposure to hematology in the time since course completion. WFindings and Discussion: We found a meaningful and statistically significant increase in the understanding gained by using TBL, but this did not lead to better long-term retention. The immediate impact of improved knowledge is consistent with prior research on TBL and may be sufficient to justify its use, as improved scores on short-term testing testing has value for student well-being, generating an interest in hematology, and competitiveness for residency application. However, our findings argue against justifying the adoption of TBL on the basis of superior long-term retention. Despite this TBL may still be of long-term benefit through modeling team decision making and self-directed learning that are core features of how clinical medicine is practiced. The impact of TBL on these components of clinical efficacy and on an interest in hematology remains areas for future study. Figure Disclosures Binder: Janssen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy.


2019 ◽  
Vol 30 (1) ◽  
pp. 107-113
Author(s):  
Rositsa Ivanova

Short-term assets are enterprise‘s resources that are involved in its business within the frames of one reporting period and their value is fully carried over to the finished product. In their nature, these are the working capital that can be classified as enterprise‘s liquid assets. The question of short-term assets‘ turnover is topical at all stages and phases of the enterprise‘s development due to the following more important reasons: 1) The acceleration of short-term assets‘ turnover results in the release of resources that can be used in accordance with the decisions made by the enterprise‘s management, and the deceleration of turnover results in difficulties for the business due to shortage of working capital. 2) The acceleration of the turnover of this working capital results in increasing the level of total rate of return of assets, and vice versa – the total rate of return of assets decreases as a result of the deceleration of short-term assets‘ turnover. 3) Turnover of working capital is a factor affecting the enterprise‘s liquidity. 4) The efficient control of the objective dependence between the rate of return and the liquidity suggests and requires analyzing and evaluating the turnover of enterprise‘s short-term assets. This publication studies the turnover of short-term assets, and its subject covers the methodology for analysis of the turnover of these resources of the enterprise. The aim of this study is to present a complex methodology for analysis of short-term assets‘ turnover, and the acceleration or decelerations of their turnover are analyzed from two perspectives. On one hand, they are analyzed as a resultative indicator by identifying the strength and direction of impact of direct factors. On the other hand, acceleration or deceleration of working capital‘s turnover is analyzed as a factor affecting the dynamics of other important business indicators – assets- and liquidity-based rate of return. For the purposes of achieving the aim of this publication the following tasks are defined: 1) The information provision of the analysis is clarified. 2) The indicators for analysis of short-term assets‘ turnover are determined. 3) It is identified whether the turnover of enterprise‘s short-term assets is accelerated or decelerated – as a whole, by groups and by types of assets. 4) The amount of released and the additionally involved short-term assets, respectively, as a result of acceleration, respectively, deceleration of their turnover, is determined. 5) The impact of direct factors on acceleration, respectively, deceleration of short-term assets‘ turnover is identified. 6) The methodologies for analysis of the impact of changes of short-term assets‘ turnover on the total rate of return of assets and on liquidity are determined. Methodologies for analysis of short-term assets‘ turnover are useful both for external and internal users of information. Based on the resultative analytical information, external users build their strategy to establish business contacts with the enterprise. Internal users are able to carry out comprehensive analysis of short-term assets‘ turnover and to make justified and proper decisions for the management of the working capital and the business of the enterprise in operative and strategic aspect.


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