Essays on bounded rationality: Individual decision and strategic interaction

Economics is a social science which, therefore, focuses on people and on the decisions they make, be it in an individual context, or in group situations. It studies human choices, in face of needs to be fulfilled, and a limited amount of resources to fulfill them. For a long time, there was a convergence between the normative and positive views of human behavior, in that the ideal and predicted decisions of agents in economic models were entangled in one single concept. That is, it was assumed that the best that could be done in each situation was exactly the choice that would prevail. Or, at least, that the facts that economics needed to explain could be understood in the light of models in which individual agents act as if they are able to make ideal decisions. However, in the last decades, the complexity of the environment in which economic decisions are made and the limits on the ability of agents to deal with it have been recognized, and incorporated into models of decision making in what came to be known as the bounded rationality paradigm. This was triggered by the incapacity of the unboundedly rationality paradigm to explain observed phenomena and behavior. This thesis contributes to the literature in three different ways. Chapter 1 is a survey on bounded rationality, which gathers and organizes the contributions to the field since Simon (1955) first recognized the necessity to account for the limits on human rationality. The focus of the survey is on theoretical work rather than the experimental literature which presents evidence of actual behavior that differs from what classic rationality predicts. The general framework is as follows. Given a set of exogenous variables, the economic agent needs to choose an element from the choice set that is avail- able to him, in order to optimize the expected value of an objective function (assuming his preferences are representable by such a function). If this problem is too complex for the agent to deal with, one or more of its elements is simplified. Each bounded rationality theory is categorized according to the most relevant element it simplifes. Chapter 2 proposes a novel theory of bounded rationality. Much in the same fashion as Conlisk (1980) and Gabaix (2014), we assume that thinking is costly in the sense that agents have to pay a cost for performing mental operations. In our model, if they choose not to think, such cost is avoided, but they are left with a single alternative, labeled the default choice. We exemplify the idea with a very simple model of consumer choice and identify the concept of isofin curves, i.e., sets of default choices which generate the same utility net of thinking cost. Then, we apply the idea to a linear symmetric Cournot duopoly, in which the default choice can be interpreted as the most natural quantity to be produced in the market. We find that, as the thinking cost increases, the number of firms thinking in equilibrium decreases. More interestingly, for intermediate levels of thinking cost, an equilibrium in which one of the firms chooses the default quantity and the other best responds to it exists, generating asymmetric choices in a symmetric model. Our model is able to explain well-known regularities identified in the Cournot experimental literature, such as the adoption of different strategies by players (Huck et al. , 1999), the inter temporal rigidity of choices (Bosch-Dom enech & Vriend, 2003) and the dispersion of quantities in the context of di cult decision making (Bosch-Dom enech & Vriend, 2003). Chapter 3 applies a model of bounded rationality in a game-theoretic set- ting to the well-known turnout paradox in large elections, pivotal probabilities vanish very quickly and no one should vote, in sharp contrast with the ob- served high levels of turnout. Inspired by the concept of rhizomatic thinking, introduced by Bravo-Furtado & Côrte-Real (2009a), we assume that each per- son is self-delusional in the sense that, when making a decision, she believes that a fraction of the people who support the same party decides alike, even if no communication is established between them. This kind of belief simplifies the decision of the agent, as it reduces the number of players he believes to be playing against { it is thus a bounded rationality approach. Studying a two-party first-past-the-post election with a continuum of self-delusional agents, we show that the turnout rate is positive in all the possible equilibria, and that it can be as high as 100%. The game displays multiple equilibria, at least one of which entails a victory of the bigger party. The smaller one may also win, provided its relative size is not too small; more self-delusional voters in the minority party decreases this threshold size. Our model is able to explain some empirical facts, such as the possibility that a close election leads to low turnout (Geys, 2006), a lower margin of victory when turnout is higher (Geys, 2006) and high turnout rates favoring the minority (Bernhagen & Marsh, 1997).

Sodium serum levels in hypoalbuminemic adults at general medical wards

Hypoalbuminemia may cause interstitial edema and hemodilution, which we hypothesized may influence serum sodium levels. Our purpose was to compare serum sodium levels of hospitalized adults with or without hypoalbuminemia. All sodium and albumin serum levels of 142 adults hospitalized at general medical wards over a six-month period were searched at a University Hospital mainframe computer. Relevant laboratory data and clinical details were also registered. Hypoalbuminemia was defined by serum albumin concentration < 3.3 g/dl Fisher, Mann-Whitney, and Student's t tests were applied to compare groups with or without hypoalbuminemia. Ninety-nine patients, classified as hypoalbuminemic, had lower blood hemoglobin (10.68 ± 2.62 vs. 13.54 ± 2.41), and sodium (135.1 ± 6.44 vs. 139.9 ± 4.76mEq/l) and albumin (2.74 ± 0.35 vs. 3.58 ± 0.28g/dl) serum levels than non-hypoalbuminemic (n=43). Pearson's coefficient showed a significant direct correlation between albumin and sodium serum levels (r=0.40) and between serum albumin and blood hemoglobin concentration (r=0.46). Our results suggest that hypoalbuminemic adults have lower serum sodium levels than those without hypoalbuminemia, a phenomenon that may be at least partially attributed to body water retention associated with acute phase response syndrome.

Orifice diseases project - experience of the "Hospital das Clínicas" University of São Paulo Medical Center in day-hospital of anorectal disease

The treatment of malignant or benign colorectal pathologies that require more complex management are priorities in tertiary hospitals such as "Hospital das Clínicas" University of São Paulo Medical Center (HCFMUSP). Therefore, benign, uncomplicated orifice conditions are relegated to second place. The number of patients with hemorrhoids, perianal fistulas, fissures, condylomas and pilonidal cysts who seek treatment at the HFMUSP is very great, resulting in over-crowding in the outpatient clinics and a long waiting list for recommended surgical treatment (at times over 18 months). The authors describe the experience of the HCFMUSP over an eight-day period with day-hospital surgery in which 140 patients underwent surgery. Data was prospectively taken on the patients undergoing surgery for benign orifice pathologies including age, sex, diagnosis, surgery performed, immediate and late postoperative complications, and follow-up. 140 patients operated on over eight days were studied. 68 were males (48.75%) with ages ranging from 25 to 62 (mean 35.2 yrs.). Hemorrhoids was the most frequent condition encountered (82 hemorrhoidectomies, 58.6%), followed by perineal fistula (28 fistula repairs, 20.0%). The most common complication was headache secondary to rachianesthesia occurring in 9 patients (6.4%). One patient (0.7%) developed bleeding immediately PO that required reoperation. Mean follow-up was 104 days. Day-surgery characterized by quality care and low morbidity is feasible in tertiary public hospitals, permitting surgery for benign orifice pathologies on many patients within a short period of time.

Assessment of medical courses in Brazil using student-completed questionnaires. Is it reliable?

INTRODUCTION: Debates about the quality of medical education have become more evident in the recent past, and as a result several different assessment methods have been refined for that purpose. The use of questionnaires filled out by medical students to assess the quality of lectures is one of the most common methods employed in our milieu. However, the reliability of this investigation method has not yet been systematically tested. The authors present the reliability of a specific form applied to the fourth grade medical students during the clinical psychiatry course. METHOD: Eighty-one fourth grade medical students were instructed to complete a form immediately after each clinical psychiatry lecture. Thirty-four students (42%) failed to turn in the forms after the final lecture. These students were given an identical form to assess the lectures in a retrospective fashion. The grades given by both groups of students for each performed lecture and the number of students who have graded an unperformed lecture were compared. Statistical significance for both groups was determined by means of the chi-square test (p< 0.05). RESULTS: Eighteen out of the 34 students who filled out the forms retrospectively (53%) rated the unperformed lecture, whereas only 5 out of the 47 students who filled out the forms during the course (11%) did so. This is statistically significant (p< 0.05). There was no statistical difference for the grades given to the lectures that were actually performed. DISCUSSION: The authors concluded the low reliability rate of the retrospective evaluation warrant a continuous assessment method during the course.

The World Health Organization Multi-Professional Patient Safety Curriculum : implementation of key modules and its impact on patient safety knowledge, skills, and attitudes of medical students at the University of Algarve

ABSTRACT - Objectives: We attempted to show how the implementation of the key elements of the World Health Organization Patient Safety Curriculum Guide Multi-professional Edition in an undergraduate curriculum affected the knowledge, skills, and attitudes towards patient safety in a graduate entry Portuguese Medical School. Methods: After receiving formal recognition by the WHO as a Complementary Test Site and approval of the organizational ethics committee , the validated pre-course questionnaires measuring the knowledge, skills, and attitudes to patient safety were administered to the 2nd and3rd year students pursuing a four-year course (N = 46). The key modules of the curriculum were implemented over the academic year by employing a variety of learning strategies including expert lecturers, small group problem-based teaching sessions, and Simulation Laboratory sessions. The identical questionnaires were then administered and the impact was measured. The Curriculum Guide was evaluated as a health education tool in this context. Results: A significant number of the respondents, 47 % (n = 22), reported having received some form of prior patient safety training. The effect on Patient Safety Knowledge was assessed by using the percentage of correct pre- and post-course answers to construct 2 × 2 contingency tables and by applying Fishers’ test (two-tailed). No significant differences were detected (p < 0.05). To assess the effect of the intervention on Patient Safety skills and attitudes, the mean and standard deviation were calculated for the pre and post-course responses, and independent samples were subjected to Mann-Whitney’s test. The attitudinal survey indicated a very high baseline incidence of desirable attitudes and skills toward patient safety. Significant changes were detected (p < 0.05) regarding what should happen if an error is made (p = 0.016), the role of healthcare organizations in error reporting (p = 0.006), and the extent of medical error (p = 0.005). Conclusions: The implementation of selected modules of the WHO Patient Safety Curriculum was associated with a number of positive changes regarding patient safety skills and attitudes, with a baseline incidence of highly desirable patient safety attitudes, but no measureable change on the patient safety knowledge, at the University of Algarve Medical School. The significance of these results is discussed along with implications and suggestions for future research.

The general practitioner and the surgeon: stereotypes and medical specialties

OBJECTIVE: To investigate and characterize the professional stereotypes associated with general medicine and surgery among Brazilian medical residents. METHODS: A randomized sample of residents of the General Medicine and Surgery Residence Programs were interviewed and their perceptions and views of general and surgical doctors were compared. RESULTS: The general practitioner was characterized by the residents in general to be principally a sensitive and concerned doctor with a close relationship with the patient; (45%); calm, tranquil, and balanced (27%); with intellectual skills (25%); meticulous and attentive to details (23%); slow to resolve problems and make decisions (22%); and working more with probabilities and hypotheses (20%). The surgeon was considered to be practical and objective (40%); quickly resolving problems (35%); technical with manual skills (23%); omnipotent, arrogant, and domineering (23%); anxious, stressed, nervous, and temperamental (23%); and more decided, secure, and courageous (20%). Only the residents of general medicine attributed the surgeon with less knowledge of medicine and only the surgeons attributed gender characteristics to their own specialty. CONCLUSION: There was considerable similarity in the description of a typical general practitioner and surgeon among the residents in general, regardless of the specialty they had chosen. It was interesting to observe that these stereotypes persist despite the transformations in the history of medicine, i.e. the first physicians (especially regarding the valorization of knowledge) and the first surgeons, so-called "barber surgeons" in Brazil (associated with less knowledge and the performance of high-risk procedures).

Royal Philips Medical Technology

Equity research report

Effects of medical therapy, alcohol, smoking, and endocrine disruptors on male infertility

Infertility affects up to 15% of the sexually active population, and in 50% of cases, a male factor is involved, either as a primary problem or in combination with a problem in the female partner. Because many commonly encountered drugs and medications can have a detrimental effect on male fertility, the medical evaluation should include a discussion regarding the use of recreational and illicit drugs, medications, and other substances that may impair fertility. With the knowledge of which drugs and medications may be detrimental to fertility, it may be possible to modify medication regimens or convince a patient to modify habits to decrease adverse effects on fertility and improve the chances of achieving a successful pregnancy. Concern is growing that male sexual development and reproduction have changed for the worse over the past 30 to 50 years. Although some reports find no changes, others suggest that sperm counts appear to be decreasing and that the incidence of developmental abnormalities such as hypospadias and cryptorchidism appears to be increasing, as is the incidence of testicular cancer. These concerns center around the possibility that our environment is contaminated with chemicals - both natural and synthetic - that can interact with the endocrine system.

Improving quality of medical service with mobile health software

An increasing number of m-Health applications are being developed benefiting health service delivery. In this paper, a new methodology based on the principle of calm computing applied to diagnostic and therapeutic procedure reporting is proposed. A mobile application was designed for the physicians of one of the Portuguese major hospitals, which takes advantage of a multi-agent interoperability platform, the Agency for the Integration, Diffusion and Archive (AIDA). This application allows the visualization of inpatients and outpatients medical reports in a quicker and safer manner, in addition to offer a remote access to information. This project shows the advantages in the use of mobile software in a medical environment but the first step is always to build or use an interoperability platform, flexible, adaptable and pervasive. The platform offers a comprehensive set of services that restricts the development of mobile software almost exclusively to the mobile user interface design. The technology was tested and assessed in a real context by intensivists.

Development of polymer wicks for the fabrication of bio-medical sensors

Polymer based wicking structures were fabricated by sintering powders of polycarbonate (PC), ultra-high molecular weight polyethylene and polyamide 12, aiming at selecting a suitable material for an innovative electroencephalography (EEG) bio-electrode. Preliminary experiments showed that PC based wicks displayed the best mechanical properties, therefore more detailed studies were carried out with PC to evaluate the influence of powder granulometry and processing parameters (pressure, temperature and time) on the mechanical properties, porosity, mean pore radius and permeability of the wicks. It was concluded that the mechanical properties are significantly enhanced by increasing the processing time and pressure, although at the expense of a significant decrease of porosity and mean pore diameter (and thus permeability), particularly for the highest applied pressures (74kPa). However, a good compromise between porosity/permeability and mechanical properties could be obtained by sintering PC powders of particle sizes below 500μm at 165°C for 5min, upon an applied pressure of 56kPa. Moreover, PC proved to be chemically stable in contact with an EEG common used disinfectant. Thus, wicking structures with appropriate properties for the fabrication of reusable bio-electrodes could be fabricated from the sintering of PC powders.

DOTA-based Ga(III) and Gd(III) chelates for medical imaging (PET, SPECT and MRI)

PhD Thesis in Sciences Specialization in Chemistry

Level of compliance in contact lens wearing medical doctors in Nepal

PURPOSES: To determine the level of compliance and major non-compliant behaviors in contact lens (CL) wearing medical doctors (MDs) and to compare it with age matched CL wearing normal subjects with no medical background (NS). METHODS: Thirty-nine current CL wearing MDs, who were prescribed CLs in Nepal Eye Hospital, Kathmandu, Nepal, between 2007 and 2011, were interviewed on ten modifiable compliant behaviors regarding lens care and maintenance. The level of compliance and the rate of non-compliance for each behavior were determined and compared with NS. RESULTS: Level of compliance was good, average and poor in 35.9%, 48.7% and 15.4% of MDs, respectively. There was no significant difference in compliance between MDs and NS (p=0.209). Level of compliance was not associated with age, gender and duration of lens wear (p>0.05). Compliance rate varied according to different behaviors, achieving a good compliance level of 95% for hand hygiene, avoidance of water contact and not sleeping with lenses. There was poor compliance for topping up solution (53.8%) and lens case replacement (15.4%). CONCLUSION: About one third of MDs had a good level of compliance. Level of compliance and compliance rate of different behaviors were similar in MDs and NS. Periodic lens case replacement was the most neglected behavior in CL wearers for this region.

Common mental disorders among medical students

OBJECTIVE: Common mental disorders (CMD) have a high impact on interpersonal relationships and quality of life and are potential underlying causes for the development of more serious disorders. Medical students have been indicated as a risk population for the development of CMD. The aim of this study was to determine the frequency of CMD in undergraduate medical students and to identify related factors. METHODS: A cross-sectional study was performed in a sample population of medical students. CMD was identified according to the 20-item Self-Report Questionnaire. RESULTS: Two hundred and twenty-three students completed the questionnaire. The overall prevalence of CMD was 29.6% and its presence was independently associated with sleep disorders, not owning a car, not working and sedentary lifestyle. CONCLUSIONS: These findings indicate a high prevalence of CMD in the sample studied and are important for supporting actions to prevent mental disorders in future doctors and for reflecting on the curricula currently in use in medical schools.