A pesquisa traz uma crítica à teoria moderna de finanças em relação à política de gestão de risco, especificamente sobre o Value at Risk, e como ela afeta o risco na economia. O trabalho propõe uma discussão comportamental da ineficácia do VaR e como este tipo de informação pode ser ruim para a economia, por refletir no problema do moral hazard (risco moral) para os gestores, baseados na ilusão de compreensão, ilusão de validade e de habilidade. A dissertação conclui que,ao superestimar a informação do VaR, os agentes alteram seu comportamento para tomar decisão e, com este risco moral, podem gerar o problema dos black swans (cisnes negros). / The research brings a critique of modern finance theory in relation to risk management policy, specifically on the Value at Risk, and how this affects the risk in the economy. The paper proposes a behavioral discussion of VaR ineffectiveness and how such information may be bad in the economy, for reflecting on the moral hazard problem for managers, based on the illusion of understanding, illusion of validity and ability. The dissertation concludes that, to overestimate VaR information, the agents change their behavior to take this decision and, this moral hazard, can generate the black swans.

In the late Middle Ages, there was a series of instances wherein knights vowed upon birds. Two of these, the first and the last, are historical events: The Feast of the Swans with Edward I in England on 22 May 1306 and the Feast of the Pheasant with Philip the Good in the duchy of Burgundy on 17 February 1454. Edward I held the Feast of the Swans as part of his son's dubbing ceremony, including the entire court taking vows on two swans. The Feast of the Pheasant was an elaborate banquet that Philip the Good used to gather support for a crusade. The other three are literary texts: the Voeux du paon, the Voeux de l’épervier, and the Voeux du héron. The Voeux du Paon contains an account of a group of nobility connected to Alexander the Great at a truce banquet. One of the prisoners accidentally kills a lady's peacock and the group decides to take vows on it before recommencing battle. The Voeux de l’épervier concerns Henry VII of Luxembourg en route to Italy to claim the title of Holy Roman Emperor. One of his knights accidentally kills a sparrowhawk and they decide, as a court, to take vows on it. Lastly, the Voeux du héron depicts Robert d' Artois inciting Edward III to initiate the Hundred Years' War over a heron. Each of these instances creates a sub-set, the bird vow cycle, within medieval vowing tradition. The origin of the bird vow cycle lies within that vowing tradition. John L. Grigsby has declared these instances as a crystallization of the gab convention of medieval literature. However, Grigsby ignored the Feast of the Swans and the Feast of the Pheasant since he was concentrated on defining a literary genre. This thesis attempts to show the bird vow cycle as connected this this literary tradition, but also a crystallization of the courtly culture that had developped in the late Middle Ages. It also attempts to show the origins of this cycle—it not only came out of a vowing tradition, but also is tied to King Arthur traditions. The culture of the late Middle Ages was nostalgic and looking back towards an idealistic version of the past—whether in legends like Arthur or historical figures like Alexander. Thus, the knightly bird vow cycle was a particular example of that fantasy in their culture. In conclusion, this thesis not only gathers together what literature there is on the knightly bird vow cycle, but it places it within a literary and historical context. The knightly bird vow cycle would not have been possible without a culture obsessed with fantasy and idealistic courtly culture.

The drivers of fidelity and divorce of pair-bonded individuals, along with their fitness consequences, are of great interest as they influence mating systems, population structure and productivity, and gene flow. Socially monogamous birds offer an ideal opportunity to study divorce since they show great variability in the extent to which pair bonds are maintained. However, there has been little consensus as to whether divorce is a behavioural adaptation to improve a mating situation, or a consequence of other processes. Moreover, the biological and ecological correlates of fidelity are difficult to address because previous work has been based on indirect and potentially biased methods. Finally, in terms of process, the link between the process of mate choice and subsequent mating decisions has been largely inaccessible to study. My doctoral thesis addressed these significant gaps in our understanding of cause, process and consequence in the formation and dissolution of pair bonds in socially monogamous birds. I accomplished this in three principal ways. First, I conducted a robust phylogenetic meta-analysis on 84 studies across 64 species to assess the existing empirical evidence that divorce in socially monogamous birds is adaptive (in terms of breeding success). This analysis revealed that divorce is, in general, adaptive as it is both triggered by relatively low breeding success and leads to improvement in success. Next, I developed a novel probabilistic multievent capture–mark–recapture framework that provides joint estimates of survival and fidelity while explicitly accounting for imperfect detection, capture heterogeneity, and uncertainty in pair status. By applying this model to breeding data on a wild great tit population I showed that birds that remain faithful to their partner exhibit higher survival rates and are more likely to remain faithful in the next breeding season than do birds that change partners. Subsequently, I confirmed the generality of a survival benefit by applying the model to breeding data on other tit populations. Then, by applying the model to data from a population of mute swans, I showed that fidelity decreases the likelihood of skipping breeding and mortality in this long-lived species, and that these effects depended on age, individual quality, and immigration status. Finally, I investigated how the timing of pair formation influences breeding success and divorce probability using five years of data on the over-winter social behaviour of great tits. I showed that early pair formation had a positive effect on fitness components, influencing the likelihood of divorce only indirectly, through breeding success. Further, my work revealed that males, but not females, with higher numbers of the female associates in winter, and males whose future breeding partners were ranked low amongst these, divorced more often. My research makes a significant contribution to our understanding of divorce and fidelity, and generates a number of important implications for future studies. First, my work establishes that divorce is adaptive for breeding success. Second, my results highlight that survival is an important (and likely, widespread) fitness consequence of pairing decisions. Third, I provide a novel statistically rigorous modelling framework for estimating fidelity-rates and testing hypothesis about fidelity that overcomes many of the inherent biases in traditional estimates. Fourth, it provides the first evidence for a selective advantage of early pair formation in wild, thus highlighting that there are benefits to pair familiarity that manifest via social associations of individuals prior to breeding. Finally, my work reveals the selective pressures operating via the social environment can ultimately influence the mating strategies individuals adopt.

This project aims to analyze the risk measures Value-at-Risk and Conditional-Value-at-Risk for three stock portfolios with the purpose of evaluating each method's accuracy in modelling Black Swan events. This is achieved by utilizing a parametric approach in the form of a modified (C)VaR with a Cornish-Fisher expansion, a historic approach with a time series spanning ten years and a Markov Monte Carlo simulation modeled with a Brownian motion. From this, it is revealed that the parametric approach at the 99\%-level generates the most favorable results for a 30-day-(C)VaR estimation for each portfolio, followed by the historic approach and, lastly, the Markov Monte Carlo simulation. As such, it is concluded that the parametric approach may serve as a method of evaluating a portfolio's exposure to Black Swan events. / Denna rapport syftar till att analysera riskmåtten Value-at-Risk och Conditional-Value-at-Risk för tre aktieportföljer med målet att utvärdera respektive metods precision i att modellera Black Swan-händelser. Detta uppnås genom att utnyttja en parametrisk metod som tar formen av en modifierad (C)VaR med en Cornish-Fisher-utveckling, en historisk metod med en tidsserie som sträcker sig tio år, och en Markov Monte Carlo-simulering modellerat med en Brownian Motion. Från detta påvisas det att den parametriska metoden vid en 99\%-ig nivå genererar de mest rättvisande resultaten för en 30-dagars-(C)VaR-estimering för respektive portfölj, följt av den historiska metoden och, till sist, Monte Carlo-simulering. På så sätt dras slutsatsen att den parametriska metoden skulle kunna tjäna som en metod för att utvärdera en aktieportföljs exponering till Black Swan-händelser.