Herding during different types of crises: The COVID-19 health crisis and Russia-Ukraine political crisis.

We analysed herding behaviour in the recent pandemic and conflict. We employed the cross-sectional dispersion of daily stock returns to estimate herding's intensity in the Saudi stock market. We conducted all analyses for the entire sample and four sub-samples. Additionally, we investigate the existence of the asymmetry in the investors' responses; whether there are differences between up and down markets and between high-volatility and low-volatility days. We found that herding did not occur in the pre-COVID-19, occurred in the during-COVID-19, disappeared in the post-COVID-19 and did not occur during the Russia-Ukraine conflict. Robustness checks confirm our finding that herding manifested in the during-COVID-19 period. Additionally, no difference exists between bearish and bullish or high-and low-volatility days, pushing aside the asymmetry in the investors' responses. This study may raise investors' awareness of their cognitive bias's influence on their decisions, improving market efficiency by increasing the rationality of investors' decisions.

Two High-Quality Cygnus Genome Assemblies Reveal Genomic Variations Associated with Plumage Color.

As an exemplary model for examining molecular mechanisms responsible for extreme phenotypic variations, plumage color has garnered significant interest. The Cygnus genus features two species, Cygnus olor and Cygnus atratus, that exhibit striking disparities in plumage color. However, the molecular foundation for this differentiation has remained elusive. Herein, we present two high-quality genomes for C. olor and C. atratus, procured using the Illumina and Nanopore technologies. The assembled genome of C. olor was 1.12 Gb in size with a contig N50 of 26.82 Mb, while its counterpart was 1.13 Gb in size with a contig N50 of 21.91 Mb. A comparative analysis unveiled three genes (TYR, SLC45A2, and SLC7A11) with structural variants in the melanogenic pathway. Notably, we also identified a novel gene, PWWP domain containing 2A (PWWP2A), that is related to plumage color, for the first time. Using targeted gene modification analysis, we demonstrated the potential genetic effect of the PWWP2A variant on pigment gene expression and melanin production. Finally, our findings offer insight into the intricate pattern of pigmentation and the role of polygenes in birds. Furthermore, these two high-quality genome references provide a comprehensive resource and perspective for comparative functional and genetic studies of evolution within the Cygnus genus.

Metagenomic analysis of gut microbiome and resistome of Whooper and Black Swans: a one health perspective.

BACKGROUND: With the promotion of "One Health," the health of animals and their impact on the environment have become major concerns recently. Widely distributed in China, the whooper swans (Cygnus cygnus) and black swans (Cygnus atratus) are not only important to the ecological environment, but they may also potentially influence public health security. The metagenomic approach was adopted to uncover the impacts of the gut microbiota of swans on host and public health. RESULTS: In this study, the intestinal microbiome and resistome of migratory whooper swans and captive-bred black swans were identified. The results revealed similar gut microbes and functional compositions in whooper and black swans. Interestingly, different bacteria and probiotics were enriched by overwintering whooper swans. We also found that Acinetobacter and Escherichia were significantly enriched in early wintering period swans and that clinically important pathogens were more abundant in black swans. Whooper swans and black swans are potential reservoirs of antibiotic resistance genes (ARGs) and novel ARGs, and the abundance of novel ARGs in whooper swans was significantly higher than that in black swans. Metagenomic assembly-based host tracking revealed that most ARG-carrying contigs originated from Proteobacteria (mainly Gammaproteobacteria). CONCLUSIONS: The results revealed spatiotemporal changes in microbiome and resistome in swans, providing a reference for safeguarding public health security and preventing animal epidemics.

Emerging markets equities' response to geopolitical risk: Time-frequency evidence from the Russian-Ukrainian conflict era.

This study investigates the asymmetric interdependence between geopolitical risk (GPR) and the stock markets of the top-seven emerging (E7) countries (i.e., Mexico, Russia, Turkey, India, China, Indonesia, and Brazil) in the ongoing geopolitical conflict between Russia and Ukraine. With daily datasets covering the period 01-Feb-2022 to 25-July-2022, the squared wavelet coherence (SWC) and wavelet coherence phase difference (WCPD) techniques are employed. The results underscore heterogeneous and asymmetric market-specific coherence and lead-lag patterns regarding E7 stocks' interdependence with geopolitical risk. The findings imply high comovements between Black Swan events like the Russian-Ukrainian conflict and financial markets' volatility, highlighting the essence of alternative assets or asset classes for hedging geopolitical risks in the ongoing military actions. The heterogeneous and asymmetric responses offered by E7 stocks against GPR render emerging markets equities suitable for diversification and downside hedging strategies against GPR-induced shocks. The findings are robust to the time-varying parameter vector autoregression (TVP-VAR) connectedness approach. The results' implications for portfolio managers, investors, and policymakers are discussed.

The swan genome and transcriptome, it is not all black and white.

BACKGROUND: The Australian black swan (Cygnus atratus) is an iconic species with contrasting plumage to that of the closely related northern hemisphere white swans. The relative geographic isolation of the black swan may have resulted in a limited immune repertoire and increased susceptibility to infectious diseases, notably infectious diseases from which Australia has been largely shielded. Unlike mallard ducks and the mute swan (Cygnus olor), the black swan is extremely sensitive to highly pathogenic avian influenza. Understanding this susceptibility has been impaired by the absence of any available swan genome and transcriptome information. RESULTS: Here, we generate the first chromosome-length black and mute swan genomes annotated with transcriptome data, all using long-read based pipelines generated for vertebrate species. We use these genomes and transcriptomes to show that unlike other wild waterfowl, black swans lack an expanded immune gene repertoire, lack a key viral pattern-recognition receptor in endothelial cells and mount a poorly controlled inflammatory response to highly pathogenic avian influenza. We also implicate genetic differences in SLC45A2 gene in the iconic plumage of the black swan. CONCLUSION: Together, these data suggest that the immune system of the black swan is such that should any avian viral infection become established in its native habitat, the black swan would be in a significant peril.

An explanation for unexpected population crashes in a constant environment.

Unexpected population crashes are an important feature of natural systems, yet many observed crashes have not been explained. Two difficulties in explaining population crashes are their relative rarity and the multi-causal nature of ecological systems. We approach this issue with experimental microcosms, with large numbers of replicates of red flour beetle populations (Tribolium castaneum). We determined that population crashes are caused by an interaction between stochasticity and successive episodes of density dependence: demographic stochasticity in oviposition rates occasionally produces a high density of eggs; so high that there are insufficient flour resources for subsequent larvae. This mechanism can explain unexpected population crashes in more general settings: stochasticity 'pushes' population into a regime where density dependence is severely overcompensatory. The interaction between nonlinearity and stochasticity also produces chaotic population dynamics and a double-humped one-generation population map, suggesting further possibilities for unexpected behaviour in a range of systems. We discuss the generality of our proposed mechanism, which could potentially account for previously inexplicable population crashes.

SARS-CoV-2 omicron variant: the black swan of microbiology.

The sudden emergence of the SARS-CoV-2 Omicron variant is causing major global concern due to its high number of mutations compared to previous variants, which is a relatively rare but significant event that can change the course of viral evolution, the occurrence of which might have huge consequences for the natural evolution of species in general, prompting us to rethink our knowledge on evolution.

Field-Based Distribution and Bioaccumulation Factors for Cyclic and Aliphatic Per- and Polyfluoroalkyl Substances (PFASs) in an Urban Sedentary Waterbird Population.

The field-based distribution and bioaccumulation factor (BAF) for per- and polyfluoroalkyl substances (PFASs) were determined in residential Black Swans (Cygnus atratus) from an urban lake (Melbourne, Australia). The concentrations of 46 aliphatic and cyclic PFASs were determined by HPLC-MS/MS in serum and excrement from swans, and water, sediment, aquatic macrophytes, soil, and grass samples in and around the lake. Elevated concentrations of ∑46PFASs were detected in serum (120 ng mL-1) and excrement (110 ng g-1 dw) were strongly related indicating a potential noninvasive sampling methodology. Environmental concentrations of PFASs were consistent with a highly impacted ecosystem and notably high concentrations of perfluoro-4-ethylcyclohexanesulfonate (PFECHS, 67584-42-3; C8HF15SO3) were detected in water (27 ng L-1) and swan serum (16 ng mL-1). In the absence of credible putative alternative sources of PFECHS input to the lake, we propose that the use of high-performance motorsport vehicles is a likely source of contamination to this ecosystem. The BAF of perfluorocarboxylic acids increased with each additional CF2 moiety from PFOA (15.7 L kg-1 ww) to PFDoDA (3615 L kg-1 ww). The BAF of PFECHS was estimated as 593 L kg-1 ww, which is lower compared with that of PFOS (1097 L kg-1 ww).

Endovascular management of iatrogenic vertebro-vertebral fistula: Black Swan event in C2 pedicle screw.

Background: Vertebro-vertebral fistulas (VVF) are rare. Anatomically, they consist of an arteriovenous fistula, a direct pathological communication between vertebral veins (including the epidural vertebral venous plexus) and extradural vertebral artery. The various etiologies include trauma, iatrogenic, or spontaneous (e.g., NF-1 or Ehlers Danlos Syndrome). The clinical presentation may include acute/delayed onset of radiculopathy and/or myelopathy. They may further be characterized by the delayed onset hearing loss to tinnitus and/or the sensation of water in the ear. Case Description: We report successful endovascular management for iatrogenic VVF in a 37-year-old female who was diagnosed with an odontoid fracture (Anderson type IIC). She underwent a posterior C1 lateral masses to C2 pedicle/laminar screw fixation. An intraoperative vertebro-vertebral fistulas (VVF) was recognized during the procedure and it was managed successfully with percutaneous transarterial endovascular coiling. Conclusion: Iatrogenic VVF should immediately be suspected when the implant trajectory goes slightly off track during a C1-2 fixation. Immediate postoperative DSA and MRI are advisable, irrespective of whether the patient is symptomatic. These lesions are best managed with endovascular coiling with or without detachable balloons.

BCG Vaccination: A potential tool against COVID-19 and COVID-19-like Black Swan incidents.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19), and its variants have brought unprecedented impacts to the global public health system, politics, economy, and other fields. Although more than ten COVID-19 specific vaccines have been approved for emergency use, COVID-19 prevention and control still face many challenges. Bacille Calmette-Guérin (BCG) is the only authorized vaccine used to fight against tuberculosis (TB), it has been hypothesized that BCG may prevent and control COVID-19 based on BCG-induced nonspecific immune responses. Herein, we summarized: 1) The nonspecific protection effects of BCG, such as prophylactic protection effects of BCG on nonmycobacterial infections, immunotherapy effects of BCG vaccine, and enhancement effect of BCG vaccine on unrelated vaccines; 2) Recent evidence of BCG's efficacy against SARS-COV-2 infection from ecological studies, analytical analyses, clinical trials, and animal studies; 3) Three possible mechanisms of BCG vaccine and their effects on COVID-19 control including heterologous immunity, trained immunity, and anti-inflammatory effect. We hope that this review will encourage more scientists to investigate further BCG induced non-specific immune responses and explore their mechanisms, which could be a potential tool for addressing the COVID-19 pandemic and COVID-19-like "Black Swan" events to reduce the impacts of infectious disease outbreaks on public health, politics, and economy.

Pandemic or panic? A firm-level study on the psychological and industrial impacts of COVID-19 on the Chinese stock market.

This study presents a thorough investigation of the relationship between the coronavirus disease 2019 (COVID-19) and daily stock price changes. We use several types of COVID-19 patients as indicators for exploring whether stock prices are significantly affected by COVID-19's impact. In addition, using the Chinese stock market as an example, we are particularly interested in the psychological and industrial impacts of COVID-19 on the financial market. This study makes two contributions to the literature. First, from a theoretical perspective, it shows a novel quantitative relationship between the psychological response to the pandemic and stock prices. In addition, it depicts the mechanism of the shock to the stock market by pointing out the specific functional expression of the impulse reaction. To our knowledge, this is the first theoretical calculation of the impulse of a shock to the financial market. Second, this study empirically estimates the marginal effect of the COVID-19 pandemic on fluctuations in stock market returns. By controlling for stock fundamentals, this study also estimates diverse industrial responses to pandemic stock volatility. We confirm that the COVID-19 pandemic has caused panic in the stock market, which not only depresses stock prices but also inflates volatility in daily returns. Regarding the impulse of the shock, we identify the cumulative level of the pandemic variables as well as their incremental differences. As shown by our empirical results, the terms for these differences will eventually dominate the marginal effect, which confirms the fading impulse of the shock. Finally, this study highlights some important policy implications of stock market volatility and returns to work in the industry.

Warning Signs of Potential Black Swan Outbreaks in Infectious Disease.

Black swan events in infectious disease describe rare but devastatingly large outbreaks. While experts are skeptical that such events are predictable, it might be possible to identify the warning signs of a black swan event. Specifically, following the initiation of an outbreak, key differentiating features could serve as alerts. Such features could be derived from meta-analyses of large outbreaks for multiple infectious diseases. We hypothesized there may be common features among the pathogen, environment, and host epidemiological triad that characterize an infectious disease black swan event. Using Los Alamos National Laboratory's tool, Analytics for Investigation of Disease Outbreaks, we investigated historical disease outbreak information and anomalous events for several infectious diseases. By studying 32 different infectious diseases and global outbreaks, we observed that in the past 20-30 years, there have been potential black swan events in the majority of infectious diseases analyzed. Importantly, these potential black swan events cannot be attributed to the first introduction of the disease to a susceptible host population. This paper describes our observations and perspectives and illustrates the value of broad analysis of data across the infectious disease realm, providing insights that may not be possible when we focus on singular infectious agents or diseases. Data analytics could be developed to warn health authorities at the beginning of an outbreak of an impending black swan event. Such tools could complement traditional epidemiological modeling to help forecast future large outbreaks and facilitate timely warning and effective, targeted resource allocation for mitigation efforts.

A Black Swan event-based hybrid model for Indian stock markets' trends prediction.

Among all the application areas of the time-series prediction, stock market prediction is the most challenging task due to its dynamic nature, and dependency on many volatile factors. The unpredictable fatal events called Black Swan events also highly influence the stock market. If the successful stock trends prediction is achieved, then the investors can adopt a more appropriate trading strategy, and that can significantly reduce the risk of investment. In this work, a time-efficient hybrid stock trends prediction framework(HSTPF) is proposed to successfully predict the future trends of the stock market even during the periods of Black Swan events. Here, to improve the prediction accuracy of HSTPF, the Black Swan events analysis and features selection operations are performed, and also the performance of various machine learning classifiers are analyzed. A vast number of experiments are conducted on the two real-world stock market datasets S&P BSE SENSEX and Nifty 50, to analyze the performance of the proposed framework. The framework is applied for the single-step and multi-step ahead predictions. The experimental results show that the proposed framework produces over 86% of accuracy, and during the Black Swan events, its accuracy is almost 80% for single-step ahead predictions. For the multi-step ahead of predictions, the HSTPF is produced satisfactory results. The framework also outperforms other existing similar works even during the Black Swan events in terms of prediction accuracy, and its computational time is also very low.

Risking Everything in Obsessive-Compulsive Disorder: An Analogue Decision-Making Study.

An experiment examined decision-making processes among nonclinical participants with low or high levels of OCD symptomatology (N = 303). To better simulate the decision environments that are most likely to be problematic for clients with OCD, we employed decision tasks that incorporated "black swan" options that have a very low probability but involve substantial loss. When faced with a choice between a safer option that involved no risk of loss or a riskier alternative with a very low probability of substantial loss, most participants chose the safer option regardless of OCD symptom level. However, when faced with choices between options that had similar expected values to the previous choices, but where each option had some low risk of a substantial loss, there was a significant shift towards riskier decisions. These effects were stronger when the task involved a contamination based, health-relevant decision task as compared to one with financial outcomes. The results suggest that both low and high symptom OC participants approach decisions involving risk-free options and decisions involving risky alternatives in qualitatively different ways. There was some evidence that measures of impulsivity were better predictors of the shift to risky decision making than OCD symptomatology.

Disaster Risk Planning With Fuzzy Goal Programming.

The uncertainty in the timing and severity of disaster events makes the long-term planning of mitigation and recovery actions both critical and extremely difficult. Planners often use expected values for hazard occurrences, leaving communities vulnerable to worse-than-usual and even so-called "black swan" events. This research models disasters in terms of their best-case, most-likely, and worst-case damage estimates. These values are then embedded in a fuzzy goal programming model to provide community planners and stakeholders with the ability to strategize for any range of events from best-case to worst-case by adjusting goal weights. Examples are given illustrating the modeling approach, and an analysis is provided to illustrate how planners might use the model as a planning tool.

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

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.

Duck virus enteritis (duck plague) outbreak in an Australian black swan (Cygnus atratus) flock at safari park in Bangladesh: A case report.

OBJECTIVE: Duck virus enteritis is a severe viral disease that kills ducks and swans worldwide. The clinical manifestations, gross pathology, molecular detection, and characterization of the duck virus enteritis virus (DVEV) in Australian black swans at a safari park in Bangladesh were described in this case report. MATERIALS AND METHODS: On a safari park in Bangladesh, an Australian black swan flock exhibited clinical signs of anorexia, greenish watery diarrhea, increased thirst, partial paralysis, and death. Postmortem examinations of deceased swans revealed extensive pathological abnormalities in the trachea, liver, and spleen. To isolate DVEV, a viral inoculum produced from the liver and spleen of dead swans was implanted into 9-13-day-old embryonated duck eggs via the chorioallantoic membrane (CAM) route. DVEV was confirmed using a polymerase chain reaction (PCR) assay. Phylogenetic analysis was used to determine the genetic relationship between the DVEV isolates from Australian black swans, and 16 DVEV isolates previously described in the GenBank. RESULTS: Hemorrhage was noted in the annular ring of the trachea, as well as an enlarged and hemorrhagic liver and spleen. The PCR assay amplified a 446-bp fragment of the DVEV DNA polymerase gene in the liver, spleen, and CAM homogenates. The phylogenetic analysis found that the DVEV isolates from swans were comparable to those from Bangladesh, India, Vietnam, China, Germany, the USA, and Egypt. CONCLUSION: According to the findings of this study, the DVEV was the cause of illness and mortality in an Australian black swan flock.

Swans and elephants: A typology to capture the challenges of food supply chain risk assessment.

As a result of internal or external shocks, food supply chains can transition between existing regimes of assembly and planned activity to situations that are unexpected or unknown. These events can occur without warning, causing stress, shift, even collapse, and impact on business/supply chain viability.

Global Psychological Implications of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Coronavirus Disease-2019 (COVID-19). What Can Be Learned From Italy. Reflections, Perspectives, Opportunities.

On December 31, 2019, the Chinese authorities announced that in the city of Wuhan, Hubei Province, central-eastern China, a cluster of pneumonia cases of unknown etiology had developed. A new coronavirus (SARS-CoV-2) that causes serious problems like pneumonia and even death, has been discovered. This new disease (COVID-19) has spread also in Italy starting from the first recognized case on February 20. Beyond its biological implications, this coronavirus allows us many psychological reflections. A new virus is indeed a potentially serious problem for mankind, but it can also be an opportunity to bring the focus back to us, to observe what is happening, who we are and how we are reacting both as individuals and as a population. Even positive implication of this pandemic was discussed.