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 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.

A transient finding of fetal head entrapment caught in a uterine synechium or amniotic band

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Edward Rives ◽  
Jeff M. Denney ◽  
Brian C. Brost
Keyword(s):  
Fibrous Tissue ◽  
Significant Risk ◽  
Fetal Surgery ◽  
Fetal Head ◽  
Still Images ◽  
Amniotic Band ◽  
Case Presentation ◽  
First Case ◽  
Uterine Synechia ◽  
Uterine Fundus

Abstract Background Uterine synechia are bands of fibrous tissue that when seen on prenatal ultrasound are not felt to pose significant risk to a fetus outside of early pregnancy loss. On the contrary, amniotic bands are diagnosed when bands of amniotic tissue are found to entrap and possible amputate involved fetal parts. Case presentation Ultrasound imaging demonstrated a twin pregnancy affected by entrapment of twin B’s head in a uterine synechium versus an amniotic band at 11 weeks + 0 days. The entrapment persisted until the second trimester. After a review of still images and video clips with a fetal surgeon, the patient was scheduled for possible fetal surgery. Upon arrival at 16 weeks + 0 days, the entrapment was observed to have spontaneously resolved. The patient experienced preterm premature rupture of membranes at 17 weeks + 6 days, and developed chorioamnionitis at 18 weeks + 5 days. Shortly after diagnosis with chorioamnionitis, she delivered spontaneously at 18 weeks + 5 days. Postnatal hysteroscopy demonstrated uterine synechium at the uterine fundus, which was resected. Conclusions This is the first case of fetal head entrapment by a uterine synechium.

scholarly journals Molecular characterization of a ceftriaxone-resistant Neisseria gonorrhoeae strain found in Switzerland

2020 ◽  
Author(s):  
Konrad Egli ◽  
Anna Roditscheff ◽  
Ursula Flückiger ◽  
Martin Risch ◽  
Lorenz Risch ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Positive Result ◽  
Limited Information ◽  
Case Presentation ◽  
Specific Pcr ◽  
Allele Type ◽  
Ciprofloxacin Resistance ◽  
Phenotypic Susceptibility ◽  
New Mutations

Abstract Background: Resistance of Neisseria gonorrhoeae to ceftriaxone is very rare in Switzerland. The underlying genotype is suspected to be novel. Generally, resistance in Neisseria gonorrhoeae (Ng) involves a comprehensive set of genes with many different mutations causing resistance to different β-lactams and fluoroquinolones.Case presentation: A patient had a positive result with specific PCR for Ng. We routinely start culturing for all clinical specimens with a positive result with NG-PCR. In this particular case, we isolated such a strain with resistance to ceftriaxone in Switzerland. A total of 7 different genes in this strain were partially sequenced for comparison with phenotypic susceptibility testing. Interestingly, two different mutations in the porinB gene were observed, and data on this gene are limited. Information on the identified allele type of the penA gene is very limited as well. Three different mutations of parC and gyrA that correlate with ciprofloxacin resistance were found.Conclusion: The combined results for all genes show the appearance of new mutations in central Europe either due to worldwide spread or the emergence of new genetic combinations.

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>

scholarly journals A case study of the first pregnant women with COVID-19 in Bukavu, Eastern DR Congo.

2020 ◽  
Author(s):  
Etienne KAJIBWAMI BIRINDWA ◽  
Guy MULINGANYA MULUMEODERHWA ◽  
Olivier NYAKIO ◽  
Guy-Quesney MATESO MBALE ◽  
Serge ZIGABE MUSHAMUKA ◽  
...  
Keyword(s):  
Risk Factors ◽  
Pregnant Women ◽  
Microscopic Examination ◽  
Sub Saharan Africa ◽  
Dr Congo ◽  
Case Presentation ◽  
History Of ◽  
Sub Saharan ◽  
In Pregnancy

Abstract Introduction: Vertical transmission of covid-19 is possible; its risk factors are worth researching. The placental changes found in pregnant women have a definite impact on the foetus.Case presentation: We report a case of a 25-year-old woman, gravida 3, para 2 (2 alive children), with a history of two caesarean deliveries, who was infected by the SARS-Cov-2 during the last term of her pregnancy. She gave birth by caesarean after 34 weeks of gestation to a new-born baby also infected with SARS-Cov-2. The per-operative observations noted several eruptive lesions in the pelvis, bleeding on contact. Microscopic examination of the foetal appendages revealed thrombotic vasculopathy in the placenta and in the umbilical cord vessels.Conclusion: This case is one of the first documented cases of COVID-19 in pregnancy in sub-Saharan Africa. We strongly suggest obstetricians to carefully examine the aspect of the peritoneum, viscera and foetal appendages in affected pregnant women.

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