scholarly journals Introduction: Black Swans and Sinatra Inferences

2022 ◽  
pp. 1-12
Author(s):  
Wolfgang Seibel
Keyword(s):  
Professional Standards ◽  
General Nature ◽  
Black Swan ◽  
Democratic Government ◽  
Governmental Agencies ◽  
Physical Integrity ◽  
Human Safety ◽  
Black Swans ◽  
Threat To Life ◽  
Public Oversight

AbstractPublic mismanagement as a threat to life and limb is a rare and highly improbable phenomenon—the proverbial Black Swan. Bridges and buildings collapse, claiming the lives of people who had every reason to believe that governmental agencies protect their physical integrity through public oversight and maintenance. Properly analyzed, however, these unlikely events reveal causal mechanisms of a general nature, strong enough to trigger fateful mismanagement even under the restrictive conditions of professional bureaucracies and democratic government. Hence the “Sinatra Inference”: When a mechanism is powerful enough ‘to make it there’—i.e., where causal leverage is supposedly low—it is likely to ‘make it everywhere’ as soon as leverage is enlarged by weaker accountability structures, lower professional standards and lesser values than human safety.

Black swans and canards in two predator – one prey model

2019 ◽  
Vol 14 (4) ◽  
pp. 408 ◽  
Author(s):  
Elena Shchepakina
Keyword(s):  
Invariant Manifold ◽  
Black Swan ◽  
Black Swans ◽  
Prey Model ◽  
Slow Invariant Manifold

In this paper, we show how canards can be easily caught in a class of 3D systems with an exact black swan (a slow invariant manifold of variable stability). We demonstrate this approach to a canard chase via the two predator – one prey model. It is shown that the technique described allows us to get various 3D oscillations by changing the shape of the trajectories of two 2D-projections of the original 3D system.

scholarly journals Aspects of the Feeding Ecology of Mallard and Black Swan in a Small Freshwater Lake

2021 ◽  
Author(s):  
◽  
Kerry John Potts
Keyword(s):  
New Zealand ◽  
Feeding Ecology ◽  
Food Supply ◽  
Freshwater Lake ◽  
Reserve Capacity ◽  
Black Swan ◽  
Feeding Patterns ◽  
Black Swans ◽  
Wetland Complex ◽  
Food Content

<p>Section 1. Limnological and waterfowl food supply characteristics of Pukepuke Lagoon are described. Emphasis is placed on describing how the balance between macrophytes and phytoplankton is established (these two forms of vegetation tend to dominate alternately in the lagoon). The question of whether heavy swan grazing may potentially shift this balance in favour of phytoplankton dominance is examined. Section 2. The year-round patterns of feeding exhibited by mallards are described on the basis of scan counts taken at one or two-hourly intervals from dawn to dusk. These feeding patterns, graphically depicted, are then interpreted and discussed against the background of what is known of the food content of the lagoon. Reference is made to the behavioural and physiological adaptability of the birds, and to the reserve capacity of the wetland complex - not just Pukepuke Lagoon - to sustain them. The relevance of these findings and interpretations, to New Zealand in general is discussed. Section 3. An hypothesis is developed to account for the way in which black swans use various waters in the Pukepuke-centred wetland complex.</p>

scholarly journals Decision-Making in Rats is Sensitive to Rare and Extreme Events: the Black Swan Avoidance

2021 ◽  
Author(s):  
Mickael Degoulet ◽  
Louis-Mattis Willem ◽  
Christelle Baunez ◽  
Stephane Luchini ◽  
Patrick Pintus
Keyword(s):  
Decision Making ◽  
Experimental Design ◽  
Extreme Events ◽  
Decision Making Under Uncertainty ◽  
Black Swan ◽  
Black Swans ◽  
Time Out ◽  
Radical Uncertainty

Most studies assessing decision-making under uncertainty use events with probabilities that are above 10-20 %. Here, to study decision-making in radical uncertainty conditions, Degoulet, Willem, Baunez, Luchini and Pintus provide a novel experimental design that aims at measuring the extent to which rats are sensitive - and how they respond - to extremely rare (below 1% of probability) but extreme events in a four-armed bandit task. Gains (sugar pellets) and losses (time-out punishments) are such that large - but rare - values materialize or not depending on the option chosen. The results show that all rats diversify their choices across options. However, most rats exhibit sensitivity to rare and extreme events despite their sparse occurrence, by combining more often options with extreme gains (Jackpots) and/or avoidance of extreme losses (Black Swans). In general, most rats choices feature one-sided sensitivity in favor of trying more often to avoid extreme losses than to seek extreme gains - that is, they feature Black Swan Avoidance.

scholarly journals Behavioral absorption of Black Swans: simulation with an artificial neural network

2021 ◽  
Author(s):  
Krzysztof Waśniewski
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Social Structure ◽  
Quantum Physics ◽  
Real Sequence ◽  
Black Swan ◽  
Black Swans ◽  
Artificial Neural ◽  
Socio Economic Variables

Abstract This article attempts to formalize the Black Swan theory as a phenomenon of collective Behavioral change. A mathematical model of collectively intelligent social structure, which absorbs random external disturbances, has been built, with a component borrowed from quantum physics, i.e. that of transitory, impossible states, represented by negative probabilities. The model served as basis for building an artificial neural network, to simulate the behaviour of a collectively intelligent social structure optimizing a real sequence of observations in selected variables of Penn Tables 9.1. The simulation led to defining three different paths of collective learning: cyclical adjustment of structural proportions, long-term optimization of size, and long-term destabilization in markets. Capital markets seem to be the most likely to develop adverse long-term volatility in response to Black Swan events, as compared to other socio-economic variables. JEL: E01, E17, J01, J11

scholarly journals Aspects of the Feeding Ecology of Mallard and Black Swan in a Small Freshwater Lake

2021 ◽  
Author(s):  
◽  
Kerry John Potts
Keyword(s):  
New Zealand ◽  
Feeding Ecology ◽  
Food Supply ◽  
Freshwater Lake ◽  
Reserve Capacity ◽  
Black Swan ◽  
Feeding Patterns ◽  
Black Swans ◽  
Wetland Complex ◽  
Food Content

<p>Section 1. Limnological and waterfowl food supply characteristics of Pukepuke Lagoon are described. Emphasis is placed on describing how the balance between macrophytes and phytoplankton is established (these two forms of vegetation tend to dominate alternately in the lagoon). The question of whether heavy swan grazing may potentially shift this balance in favour of phytoplankton dominance is examined. Section 2. The year-round patterns of feeding exhibited by mallards are described on the basis of scan counts taken at one or two-hourly intervals from dawn to dusk. These feeding patterns, graphically depicted, are then interpreted and discussed against the background of what is known of the food content of the lagoon. Reference is made to the behavioural and physiological adaptability of the birds, and to the reserve capacity of the wetland complex - not just Pukepuke Lagoon - to sustain them. The relevance of these findings and interpretations, to New Zealand in general is discussed. Section 3. An hypothesis is developed to account for the way in which black swans use various waters in the Pukepuke-centred wetland complex.</p>

Ecological Studies of the Black Swan I. The Egg, Clutch and Incubation

1977 ◽  
Vol 4 (1) ◽  
pp. 59 ◽  
Author(s):  
LW Braithwaite
Keyword(s):  
Incubation Period ◽  
Clutch Size ◽  
Egg Size ◽  
Adaptive Significance ◽  
Moisture Loss ◽  
Black Swan ◽  
Black Swans ◽  
The Difference ◽  
Method Of Assessment ◽  
Autumn And Winter

Statistics are given for egg dimensions, clutch size, laying rate and incubation period in black swans nesting at Lake George and Lake Bathurst, N.S.W., and compared with data from other studies. Methods of determining clutch size and incubation dates are given and examined. Emphasis is placed on the importance of the method of assessment of clutch size in comparisons within and between studies. There was evidence of two size classes of eggs, possibly related to factors of age or breeding experience, the smaller class being laid in summer breeding, during an exceptional abundance of food, but not in winter when food may have been limiting. Egg size varied significantly, according to sequence in the clutch. The adaptive significance of egg size is discussed; moisture loss may be important in the evolution of egg size. Clutch size varied significantly according to the location and date of nesting. The reasons for the variation were, possibly, both in the nutritional value of the food available and in its relative temporal and physical availability and the swans' abllity to metabolize it. Possible evolutionary determinants of average clutch size in the black swan are considered. Moisture losses from the egg may again he important. The laying rate was simdar to that reported elsewhere. The mean incubation period was 40.45 days and most clutches ranged from 39 to 43 days. Clutches laid in autumn and winter took marginally longer to hatch than clutches laid in spring and summer, possibly due to effects of ambient temperature; the difference was probably not of particular adaptive significance.

scholarly journals A bumblefoot outbreak and fatal septicemia in captive aquatic birds in Brazil

2009 ◽  
Vol 39 (6) ◽  
pp. 1905-1907 ◽  
Author(s):  
Marcus Vinícius Romero Marques ◽  
José Sérgio de Resende ◽  
Rogério Venâncio Donatti ◽  
Daniel Ambrózio da Rocha Vilela ◽  
Roselene Ecco ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Black Swan ◽  
Aix Sponsa ◽  
Fatal Disease ◽  
Wood Ducks ◽  
Black Swans ◽  
Eudocimus Ruber ◽  
Foot Lesions ◽  
Roseate Spoonbill ◽  
Fatal Septicemia

A bumblefoot outbreak with different prognosis according to host species was studied in captive aquatic avian species. Six wood ducks (Aix sponsa), three scarlet-ibis (Eudocimus ruber), two black-swans (Cygnus atratus), five white-faced ducks (Dendrocygna viduata) and two roseate spoonbills (Platalea ajaja) were kept in a common pen with abrasive pavement pond margin, predisposing to podal skin wear. Incoordination and mortality occurred in the two roseate spoonbils and one black swan. Coagulase-positive penicillin-resistant Staphylococcus aureus was isolated from the synovial fluid and from the liver. All birds sharing the pen presented active or cicatricial foot lesions, indicating a possible challenge to the environmental Staphylococci. However, except for the roseate spoonbill and the black swan, which had fatal disease, for all other species the case did not evolve to a clinically debilitating or fatal disease. The different susceptibility to a fatal Staphylococcus aureus coagulase positive infection is discussed.

scholarly journals Lethal infection caused by Tetratrichomonas gallinarum in black swans (Cygnus atratus)

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Shengyong Feng ◽  
Han Chang ◽  
Yutian Wang ◽  
Fubing Luo ◽  
Qiaoxing Wu ◽  
...  
Keyword(s):  
Host Range ◽  
Microscopic Examination ◽  
Fibrous Tissue ◽  
Black Swan ◽  
Mononuclear Cell Infiltration ◽  
Case Presentation ◽  
Specific Pcr ◽  
Black Swans ◽  
Lethal Infection ◽  
Mild Diarrhea

Abstract Background Tetratrichomonas gallinarum is parasitic protozoa with a wide host range. However, its lethal infection is rare reported. Case presentation Here, we described the first lethal cases of T. gallinarum infection in black swans in China. Five black swans died within a week in succession without obvious symptoms except mild diarrhea. At necropsy, severe lesions were observed in caeca with thickened caecal walls and hemorrhages in the mucosa. A large number of moving trophozoites were found in the contents of the cecum by microscopic examination. The livers were enlarged with multiple bleeding spots on the surface. Histopathology of the livers showed mononuclear cell infiltration and moderate hyperplasia of fibrous tissue. The histopathology of the cecum showed that the villi of the cecum were edematous. Finally, the presence of T. gallinarum was determined by specific PCR andin-situ hybridization assay. Additionally, common pathogens that can cause similar symptoms were excluded. Conclusions The death of the black swan was caused by T. gallinarum, suggesting that the parasite might be a new threat to the Cygnus birds.

"Black Swans" and the Financial Crisis

2012 ◽  
Vol 15 (02) ◽  
pp. 1250008 ◽  
Author(s):  
Terry Marsh ◽  
Paul Pfleiderer
Keyword(s):  
Risk Management ◽  
Standard Deviation ◽  
Asset Pricing ◽  
Financial Crisis ◽  
Financial Models ◽  
Rare Events ◽  
Black Swan ◽  
Black Swans ◽  
The One ◽  
P Distribution

Post-mortems of the financial crisis typically mention "black swans" as the rare events that were the Achilles heel of financial models, manifesting themselves as "25 standard deviation events occurring several days in a row". Here, we briefly discuss the implications of "black swan" events in asset pricing and risk management. We then show that the "black swans" problem virtually disappears for S&P Index returns when surprises are measured relative to the standard deviation of the conditional S&P distribution. In our illustration, we use the one-day-lagged VIX as an easy-to-understand measure of that conditional S&P standard deviation.

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