scholarly journals On the optimal response vigor and choice under variable motivational drives

2016 ◽  
Author(s):  
Amir Dezfouli

Within a rational framework, a decision-maker selects actions based on the reward-maximisation principle, i.e., acquiring the highest amount of reward with the lowest cost. Action selection can be divided into two dimensions: (i) selecting an action among several alternatives, and (ii) choosing the response vigor, i.e., how fast the selected action should be executed. Previous works have addressed the computational substrates of such a selection process under the assumption that outcome values are stationary and do not change during the course of a session. This assumption does not hold when the motivational drive of the decision-maker is variable, because it leads to changes in the values of the outcomes, e.g., satiety decreases the value of the outcome. Here, we utilize an optimal control framework and derive the optimal choice and response vigor under different experimental conditions. The results imply that, in contrast to previous suggestions, even under conditions that the values of the outcomes are changing during the session, the optimal response rate in an instrumental conditioning experiment is a constant response rate rather than decreasing. Furthermore, we prove that the uncertainty of the decision-maker about the duration of the session explains the commonly observed decrease in response rates within a session. We also show that when the environment consists of multiple outcomes, the model explains probability matching as well as maximisation choice strategies. These results, therefore, provide a quantitative analysis of optimal choice and response vigor under variable motivational drive, and provide predictions for future testing.

2017 ◽  
Author(s):  
Amir Dezfouli ◽  
Bernard W. Balleine ◽  
Richard Nock

AbstractWithin a rational framework a decision-maker selects actions based on the reward-maximisation principle which stipulates they acquire outcomes with the highest values at the lowest cost. Action selection can be divided into two dimensions: selecting an action from several alternatives, and choosing its vigor, i.e., how fast the selected action should be executed. Both of these dimensions depend on the values of the outcomes, and these values are often affected as more outcomes are consumed, and so are the actions. Despite this, previous works have addressed the computational substrates of optimal actions only in the specific condition that the values of outcomes are constant, and it is still unknown what the optimal actions are when the values of outcomes are non-stationary. Here, based on an optimal control framework, we derive a computational model for optimal actions under non-stationary outcome values. The results imply that even when the values of outcomes are changing, the optimal response rate is constant rather than decreasing. This finding shows that, in contrast to previous theories, the commonly observed changes in the actions cannot be purely attributed to the changes in the outcome values. We then prove that this observation can be explained based on the uncertainty about temporal horizons; e.g., in the case of experimental protocols, the session duration. We further show that when multiple outcomes are available, the model explains probability matching as well as maximisation choice strategies. The model provides, therefore, a quantitative analysis of optimal actions and explicit predictions for future testing.


Author(s):  
Xavier Charmetant ◽  
Maxime Espi ◽  
Thomas Barba ◽  
Anne Ovize ◽  
Emmanuel Morelon ◽  
...  

AbstractOnly a minority of kidney transplant recipients (KTRs) develop protective neutralizing titers of anti-receptor binding domain of spike protein (RBD) IgG after two doses of mRNA COVID-19 vaccine. Administration of a third dose of mRNA vaccine to KTRs with sub-optimal response increase anti-RBD IgG titers but with high inter-individual variability. Patients with the higher response rate to the third dose of vaccine can be identified by the presence of low anti-RBD IgG titers and spike-specific CD4+ T cells in their circulation 14 days after the second dose.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. TPS10606-TPS10606
Author(s):  
Ashleigh Porter ◽  
Audrey J. Zeh ◽  
Thu Ly ◽  
Alyssa Serna ◽  
Arturo Villanueva ◽  
...  

TPS10606 Background: The presence of pre-cancerous oral lesions such as leukoplakia or erythroleukoplakia are known risk factors for the development of squamous cell carcinoma of the head and neck (SCCHN), however preventative agents have not yet shown clinical benefit. The risk of malignant transformation varies but has been quoted as high as 36% in some studies. While the primary mode of treatment of these lesions is largely surgical, recurrence rates are high. Pembrolizumab is a potent and selective humanized monoclonal antibody that is designed to directly block the interaction between PD-1 and PD-L1 (as well as PD-L2) that is currently FDA-approved for treatment of SCCHN. We have hypothesized that the treatment of oral premalignant lesions with pembrolizumab would be an effective and well-tolerated strategy to prevent transformation to invasive cancer. Methods: This study is an open-label, phase II study that will accrue 26 patients with leukoplakia, erythroleukoplakia, or proliferative verrucous leukoplakia with documented moderate to severe dysplasia or carcinoma in situ to be treated with pembrolizumab 200mg every 3 weeks for a total of 6 months. Patients must have visible and measurable lesions that will be both photographed and measured in two dimensions at each visit from the start of treatment until 12 months post-enrollment. Biopsies will be required at diagnosis and following the final treatment, with an optional biopsy following cycle 2 and at progression of disease. Major exclusion criteria include patients with mild dysplasia or hyperplasia, prior chemotherapy, targeted small molecule therapy, or radiation therapy within 2 weeks of Day 1 of study, or patients with a known additional malignancy that is active. Patients will also be excluded if they have received anti-PD-1, anti-PD-L1 or anti-PD-L2 treatments in the past. The primary objective is clinical response rate at 6 months, and will be quantified as the percentage of patients with a complete response (CR) and partial response (PR) at 6 months. A CR is defined as complete resolution by visual inspection for 4 weeks of more and a PR is defined as 50% or greater reduction of the product of the 2 dimensions of a single lesions or the sum of all lesions. Progressive disease (PD) is defined as unequivocal increase (greater than or equal to 5mm in one dimension and greater than 20% increase) or the development of new lesions. Secondary objectives will include histologic response rate at 6 months, change in clinical impression based on photographs, clinical response rate at 9 and 12 months, and toxicity. Additional exploratory objectives will include PD-L1 expression in leukoplakia lesions as well as p16 expression, presence of tumor infiltrating lymphocytes, and immunohistochemical as well as RNA sequencing gene expression profiling which may allow for the identification of novel biomarkers. Enrollment began in June 2019 and is ongoing. Clinical trial information: NCT03603223 .


2018 ◽  
Vol 204 ◽  
pp. 02013
Author(s):  
Fatkhor Rozi ◽  
Evy Herowati

Raw materials are basic need for manufacturing companies to facilitate the production process. Therefore, supplier selection process is an important process for the company, because by choosing the right suppliers of raw materials will benefit the company. To choose the right supplier is also determined by the decision taken by the decision maker (DM). In addition, the weight of DM assessment will differ on different criteria because DM experts in a particular field are not necessarily experts in other fields. Therefore, in this paper is discussed about the measurement of the weight of each criterion and alternative to choose the best supplier alternative using AHP method. In addition, this paper also measures the consistency of DM in making decisions using expertise level models.


2017 ◽  
Vol 8 (2) ◽  
pp. 239-255 ◽  
Author(s):  
Xi Y. Leung ◽  
Billy Bai ◽  
Mehmet Erdem

Purpose The purpose of this study is to develop a typology of social media messages to compare the effectiveness of different message strategies. Design/methodology/approach In total, 1,837 messages from 12 hotel brand Facebook pages were content-analyzed. Applying both correspondence analysis and multivariate analysis of variance, the study compared message strategy across hotel-scale levels and explored the effectiveness of different message strategies. Findings A typology of four-type message format and six-type message content was developed. The picture message was the best message format. Product, brand and involvement messages were shown to be more effective than information, reward and promotion messages. Promotion message was the least effective message content type. Research limitations/implications The major limitation of this study is the generalizability owing to the sample selection process. There is also the limitation on exclusion of control variables, selection of the three effectiveness measures and evolving social media technology. Practical implications The typology of Facebook message strategy developed in the study provided guidelines for hotel marketers to create messages on Facebook pages and track effectiveness. Hotels should also take full advantage of the picture format and product, brand and involvement contents. Originality/value This study created a new typology of social media message strategy consisting of two dimensions. It also provided empirical evidence to support the application of message strategy theory in the hotel social media marketing area.


2017 ◽  
Vol 4 (4) ◽  
pp. 170097 ◽  
Author(s):  
Tatsuhiro Yamamoto ◽  
Eisuke Hasegawa

Determining the optimal choice among multiple options is necessary in various situations, and the collective rationality of groups has recently become a major topic of interest. Social insects are thought to make such optimal choices by collecting individuals' responses relating to an option's value (=a quality-graded response). However, this behaviour cannot explain the collective rationality of brains because neurons can make only ‘yes/no’ responses on the basis of the response threshold. Here, we elucidate the basic mechanism underlying the collective rationality of such simple units and show that an ant species uses this mechanism. A larger number of units respond ‘yes’ to the best option available to a collective decision-maker using only the yes/no mechanism; thus, the best option is always selected by majority decision. Colonies of the ant Myrmica kotokui preferred the better option in a binary choice experiment. The preference of a colony was demonstrated by the workers, which exhibited variable thresholds between two options' qualities. Our results demonstrate how a collective decision-maker comprising simple yes/no judgement units achieves collective rationality without using quality-graded responses. This mechanism has broad applicability to collective decision-making in brain neurons, swarm robotics and human societies.


2020 ◽  
Author(s):  
Monia Anzivino ◽  
Flavio A. Ceravolo ◽  
Michele Rostan

AbstractThe article aims at investigating Italian academics’ Public Engagement highlighting its two dimensions, namely “Local Community Engagement” (LCE) and “General Political Engagement” (GPE). It is based on the results of a national survey on academics’ third mission activities carried out in the year 2015/2016 collecting information from a representative sample of 5,123 respondents working at 62 universities, with a response rate of 34.2%. In addition to detecting distinct dimensions of academics’ Public Engagement, data analysis shows that Italian academics are much more involved in LCE activities than in GPE ones. Although both LCE and GPE are influenced by many common factors, such as academic rank, discipline and being involved in other third mission activities, they also display peculiar traits: LCE activities are more likely to involve academic women while GPE are more likely to be carried out by older academics; LCE activities appear to be context-dependent while GPE activities are not. Hence, the article offers a contribution to a better understanding of the different goals of Public Engagement activities and of their spatial dimension.


Author(s):  
Sirous Yasseri

Numerous leak detection systems (LDS) using a variety of technologies are on the market. Since LDS are designed for a particular use, then the evaluation and selection process requires suitable metrics and involvement from all stakeholders. This paper proposes to use15 criteria for selection of LDS. Each criterion is first rated for their importance by a number of experts. Then, the same experts are asked to rate a list of candidate LDSs. Fuzzy TOPSIS is used to aggregate Experts’ judgment. A case study is presented to demonstrate the application of the method. This method would indicate how a good compromise might look like. This could aid the decision-maker to weigh options and set priority and decide on a system.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2977-2977
Author(s):  
Michael Mankbadi ◽  
Lidet Alemu ◽  
Afiya Bey ◽  
Nathan T. Connell ◽  
Lisa Fanning ◽  
...  

Abstract Background The National Institutes of Health define African Americans or Blacks, American Indians, Alaska Natives, Hispanics or Latinos, Native Hawaiians, and other Pacific Islanders as being underrepresented in medicine. A number of studies have demonstrated that improving diversity of such underrepresented demographics within the medical profession improves patient outcomes, medical education and reduces health disparities in patients from vulnerable racial or socioeconomic groups. Despite this recognition, significant underrepresentation of various racial, ethnic, and sexual identities still exists within nearly all medical specialties. Aims The purpose of this study was to a gain a greater understanding of the current state of diversity, equity, and inclusion (DEI) efforts among U.S. hematology and medical oncology fellowship training programs. We explored the perspectives of adult and pediatric fellowship program directors regarding current recruitment strategies and suggestions for improvement to help mitigate the effects of implicit and explicit bias. Here, we present an interim analysis of the data using descriptive statistics. Methods: We convened a multi-institutional collaboration of fellowship program directors, teaching faculty, and staff members of the American Society of Hematology to develop a survey examining perceptions of DEI efforts among hematology and medical oncology fellowship program directors. The survey was pilot tested in a small group of program directors representing 6 different academic programs (5 adult, 1 pediatric). The final online survey was distributed via email to 224 fellowship program directors at U.S. adult and pediatric hematology and medical oncology fellowship programs. The survey included 29 questions regarding perspectives on bias within the fellowship selection process, current DEI initiatives, and current faculty and fellow demographics. Survey respondents were asked to rate the importance of numerous factors in determining which applicants to invite utilizing a scale of 0-10, with 0 and 10 representing lowest and highest importance, respectively. To measure program director perceptions of certain applicant groups, survey respondents were asked to rate applicant demographics as being advantaged/disadvantaged based on survey options ranging from 0-5, with 0 and 5 representing very disadvantaged and very advantaged, respectively. Results: At interim analysis, 41 of 224 program directors completed the survey for an interim response rate of 21%, including 25 adult program directors and 16 pediatric program directors, with representation from university and community programs. Of the program directors surveyed, 28 (68%) reported having access to a dedicated diversity committee or DEI policies in place to improve recruitment of underrepresented applicants. In determining which applicants to invite, respondents placed highest value on the applicant's program director letter (mean score ± standard deviation: 7.44±1.93), caliber of the applicant's residency program (7.28±2.06) and letters of recommendations (7.15±2.23). Survey respondents viewed white and male applicants as representing the most advantaged demographic group, while LGBTQI, age>40, and U.S. citizen and non-citizen international medical graduates were the most disadvantaged (Table 1). Suggestions regarding improving DEI in the fellowship selection process included implementing bias training, identifying potentially disadvantaged applicants in ERAS, increasing faculty diversity, and pairing underrepresented applicants with interviewers based on applicant preference. Conclusion: While the majority of hematology and medical oncology fellowship program directors report having DEI programs or policies to improve recruitment of underrepresented applicants, perceptions of advantaged/disadvantaged groups may extend beyond demographics traditionally viewed as being underrepresented in medicine. As our survey is ongoing, we plan to reanalyze our data when the survey has been finalized with a higher response rate utilizing multivariable regression to identify themes that may further improve DEI efforts within the fellowship selection process. Figure 1 Figure 1. Disclosures LaCasce: Bristol-Myers Squibb Company.: Other: Data Safetly and Monitoring. Murphy: North American Thrombosis Foundation: Honoraria. Naik: Rigel: Research Funding. Podoltsev: Pfizer: Honoraria; Blueprint Medicines: Honoraria; Incyte: Honoraria; Novartis: Honoraria; Celgene: Honoraria; PharmaEssentia: Honoraria; Bristol-Myers Squib: Honoraria; CTI BioPharma: Honoraria.


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