Giffen goods and market making

This paper shows that information effects per se are not responsible forthe Giffen goods anomaly affecting competitive traders demands in multi-asset, noisy rational expectations equilibrium models. The role thatinformation plays in traders strategies also matters. In a market withrisk averse, uninformed traders, informed agents havea dual motive for trading: speculation and market making. Whilespeculation entails using prices to assess the effect of private signalerror terms, market making requires employing them to disentangle noisetraders effects in traders aggregate orders. In a correlated environment,this complicates a trader s signal-extraction problem and maygenerate upward-sloping demand curves. Assuming either (i) that competitive,risk neutral market makers price the assets, or that (ii) the risktolerance coefficient of uninformed traders grows without bound, removesthe market making component from informed traders demands, rendering themwell behaved in prices.

Making land-use fit to planning goals. Weaknesses and opportunities within the Swiss land management regime

In Switzerland, the issue of land consumption has made it to the front of the political agenda in recent years. Studies conducted on a national level have concluded that there is an excess of land zoned for construction (ARE, 2008), which is seen as contributing to urban sprawl. This situation is looked upon as a failure of the Federal Law on Spatial Planning (LAT, 1979) and there is a political push to change it in order to reinforce zoning regulations. In this article, we look on the issue from a different angle. While there may be large quantities of land zoned for construction, in many urban areas land actually available for development is scarce. Building on the idea that planning's efficiency is linked to its capacity of influencing actual land-use, we focus on how this situation can be dealt with within the current Swiss institutional context.

A model of market-making

The two essential features of a decentralized economy taken intoaccount are, first, that individual agents need some informationabout other agents in order to meet potential trading partners,which requires some communication or interaction between theseagents, and second, that in general agents will face tradinguncertainty. We consider trade in a homogeneous commodity. Firmsdecide upon their effective supplies, and may create their ownmarkets by sending information signals communicating theirwillingness to sell. Meeting of potential trading partners isarranged in the form of shopping by consumers. The questions to beconsidered are: How do firms compete in such markets? And what arethe properties of an equilibrium? We establish existenceconditions for a symmetric Nash equilibrium in the firms'strategies, and analyze its characteristics. The developedframework appears to lend itself well to study many typicalphenomena of decentralized economies, such as the emergence ofcentral markets, the role of middlemen, and price-making.

Social value orientation as a moral intuition: Decision-making in the dictator game

We studied the decision making process in the Dictator Game and showed that decisions are the result of a two-step process. In a first step, decision makers generate an automatic, intuitive proposal. Given sufficient motivation and cognitive resources, they adjust this in a second, more deliberated phase. In line with the social intuitionist model, we show that one s Social Value Orientation determines intuitive choice tendencies in the first step, and that this effect is mediated by the dictator s perceived interpersonal closeness with the receiver. Self-interested concerns subsequently leadto a reduction of donation size in step 2. Finally, we show that increasing interpersonal closeness can promote pro-social decision-making.

Decision making in uncertain and changing environments

We consider an agent who has to repeatedly make choices in an uncertainand changing environment, who has full information of the past, who discountsfuture payoffs, but who has no prior. We provide a learning algorithm thatperforms almost as well as the best of a given finite number of experts orbenchmark strategies and does so at any point in time, provided the agentis sufficiently patient. The key is to find the appropriate degree of forgettingdistant past. Standard learning algorithms that treat recent and distant pastequally do not have the sequential epsilon optimality property.

Dynamic social representations of the 2009 H1N1 pandemic: Shifting patterns of sense-making and blame

We investigate dynamics of public perceptions of the 2009 H1N1 influenza pandemic to understand changing patterns of sense-making and blame regarding the outbreak of emerging infectious diseases. We draw on social representation theory combined with a dramaturgical perspective to identify changes in how various collectives are depicted over the course of the pandemic, according to three roles: heroes, villains and victims. Quantitative results based on content analysis of three cross-sectional waves of interviews show a shift from mentions of distant collectives (e.g., far-flung countries) at Wave 1 to local collectives (e.g., risk groups) as the pandemic became of more immediate concern (Wave 2) and declined (Wave 3). Semi-automated content analysis of media coverage shows similar results. Thematic analyses of the discourse associated with collectives revealed that many were consistently perceived as heroes, villains and victims.

The trail making test as a screening instrument for driving performance in older drivers; a translational research.

BACKGROUND: In many countries, primary care physicians determine whether or not older drivers are fit to drive. Little, however, is known regarding the effects of cognitive decline on driving performance and the means to detect it. This study explores to what extent the trail making test (TMT) can provide indications to clinicians about their older patients' on-road driving performance in the context of cognitive decline. METHODS: This translational study was nested within a cohort study and an exploratory psychophysics study. The target population of interest was constituted of older drivers in the absence of important cognitive or physical disorders. We therefore recruited and tested 404 home-dwelling drivers, aged 70 years or more and in possession of valid drivers' licenses, who volunteered to participate in a driving refresher course. Forty-five drivers also agreed to undergo further testing at our lab. On-road driving performance was evaluated by instructors during a 45 minute validated open-road circuit. Drivers were classified as either being excellent, good, moderate, or poor depending on their score on a standardized evaluation of on-road driving performance. RESULTS: The area under the receiver operator curve for detecting poorly performing drivers was 0.668 (CI95% 0.558 to 0.778) for the TMT-A, and 0.662 (CI95% 0.542 to 0.783) for the TMT-B. TMT was related to contrast sensitivity, motion direction, orientation discrimination, working memory, verbal fluency, and literacy. Older patients with a TMT-A ≥ 54 seconds or a TMT-B ≥ 150 seconds have a threefold (CI95% 1.3 to 7.0) increased risk of performing poorly during the on-road evaluation. TMT had a sensitivity of 63.6%, a specificity of 64.9%, a positive predictive value of 9.5%, and a negative predictive value of 96.9%. CONCLUSION: In screening settings, the TMT would have clinicians uselessly consider driving cessation in nine drivers out of ten. Given the important negative impact this could have on older drivers, this study confirms the TMT not to be specific enough for clinicians to justify driving cessation without complementary investigations on driving behaviors.

Patients' preferences on information and involvement in decision making for gastrointestinal surgery.

BACKGROUND: The relationship between physicians and patients has undergone important changes, and the current emancipation of patients has led to a real partnership in medical decision making. The present study aimed to assess patients' preferences on different aspects of decision making during treatment and potential complications, as well as the amount and type of preoperative information wanted before visceral surgery. METHODS: This was a prospective non-randomized study based on a questionnaire given to 253 consecutive patients scheduled for elective gastrointestinal surgery. RESULTS: In considering surgical complications or treatment in the intensive care unit, 64 % of patients wished to take an active role in any medical decisions. The respective figures for cardiac resuscitation and treatment limitations were 89 and 60 %. As for information, 73, 77, and 47 % of patients wish detailed information, information on a potential ICU hospitalization, and knowledge of cardiac resuscitation, respectively. Elderly and low-educated patients were significantly less interested in shared medical decision making (p = 0.003 and 0.015), and in receiving information (p = 0.03 and 0.05). Similarly, involvement of the family in decision making was significantly less important to elderly and male patients (p = 0.05 and 0.03, respectively). Neither the type of operation (minor or major) nor the severity of disease (malignancies versus non-malignancies) was a significant factor for shared decision making, information, or family involvement. CONCLUSIONS: The vast majority of surgical patients clearly want to get adequate preoperative information about their disease and the planned treatment. They also consider it crucial to be involved in any kind of decision making for treatment and complications. For most patients, the family role is limited to supporting the treating physicians if the patient is unable to participate in decision making.

Surrogate decision making for patients with end-stage dementia.

OBJECTIVE: We aim to explore how health surrogates of patients with dementia proceed in decision making, which considerations are decisive, and whether family surrogates and professional guardians decide differently. METHODS: We conducted an experimental vignette study using think aloud protocol analysis. Thirty-two family surrogates and professional guardians were asked to decide on two hypothetical case vignettes, concerning a feeding tube placement and a cardiac pacemaker implantation in patients with end-stage dementia. They had to verbalize their thoughts while deciding. Verbalizations were audio-recorded, transcribed, and analyzed according to content analysis. By experimentally changing variables in the vignettes, the impact of these variables on the outcome of decision making was calculated. RESULTS: Although only 25% and 31% of the relatives gave their consent to the feeding tube and pacemaker placement, respectively, 56% and 81% of the professional guardians consented to these life-sustaining measures. Relatives decided intuitively, referred to their own preferences, and focused on the patient's age, state of wellbeing, and suffering. Professional guardians showed a deliberative approach, relied on medical and legal authorities, and emphasized patient autonomy. Situational variables such as the patient's current behavior and the views of health care professionals and family members had higher impacts on decisions than the patient's prior statements or life attitudes. CONCLUSIONS: Both the process and outcome of surrogate decision making depend heavily on whether the surrogate is a relative or not. These findings have implications for the physician-surrogate relationship and legal frameworks regarding surrogacy. Copyright © 2011 John Wiley & Sons, Ltd.