biological evolution
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2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Chantelli Iamblaudiot Razafindrazoto ◽  
Noémie Trystram ◽  
Gustavo Miranda Martins ◽  
Christiane Stern ◽  
Frédéric Charlotte ◽  
...  

Abstract Background Acute cellular rejection beyond the 6th month posttransplant is an uncommon complication after liver transplantation. The inadequate immunosuppression (IS) remains the main risk factor. We report a case of acute cellular rejection after a switch to everolimus monotherapy at 11 months following liver transplantation. Case presentation This was a 69-year-old man who underwent liver transplantation after hepatocellular carcinoma. The initial immunosuppression was a combination of three immunosuppressive drugs (corticosteroids + tacrolimus + mycophenolate mofetil). The corticosteroid therapy was stopped at the 4th month posttransplant. Serious side effects of the immunosuppressive drugs (agranulocytosis and renal dysfunction), which occurred 4 months after transplantation, required a reduction and then a discontinuation of tacrolimus and mycophenolate mofetil. Everolimus was introduced as a replacement. The patient was consulted at 11 months after liver transplantation, 1 month after stopping the two immunosuppressive drugs, for liver function test abnormalities such as cytolysis and anicteric cholestasis. A moderate late acute cellular rejection was confirmed by a liver biopsy. A satisfactory biological evolution was observed following corticosteroid boluses and optimization of basic immunosuppressive drugs. Conclusion Late acute cellular rejection remains an uncommon complication, observed mostly in the first year after liver transplantation. The main risk factor is usually the decrease of immunosuppression.


2021 ◽  
pp. 543-550
Author(s):  
Nataliya Boyko ◽  
Andriy Pytel

Lately, artificial intelligence has become increasingly popular. Still, at the same time, a stereotype has been formed that AI is based solely on neural networks, even though a neural network is only one of the numerous directions of artificial intelligence. This paper aims to bring attention to other directions of AI, such as genetic algorithms. In this paper, we study the process of solving the travelling salesman problem (TSP) via genetic algorithms (GA) and consider the issues of this method. The genetic algorithm is a method for solving both constrained and unconstrained optimization problems that are based on natural selection, the process that drives biological evolution. One of the common problems in programming is the travelling salesman problem. Many methods can be used to solve it, but we are going consider genetic algorithms. This study aims at developing the most efficient application of genetic algorithms in the travelling salesman problem.


2021 ◽  
Vol 42 (2) ◽  
Author(s):  
Barend J. Du Toit

How do we know that we can trust our viewpoints, our dogmatic principles and our religious convictions to constitute veracity, if not truth? Where can an arbiter be found for our deliberations to establish the trustworthiness of our viewpoints or belief systems, when we differ one from the other on religious matters, and in the context of religious conviction also differ in political and social endeavours? Van Huyssteen deserves commendation for his contribution to this discourse in developing the concept of a postfoundationalist epistemology in an attempt to justify theology’s integrity, and endorse theology’s public voice within our highly complex and challenging world. He suggests that the concept of human uniqueness might be the common denominator in the contributions of theology (in its specific understanding of the unique status of humans in God’s creation) and science (in its understanding of the unique stature of Homo sapiens in terms of biological evolution). However, the author, in this article, argues that given the radically diverse disciplines of science in our highly developed technological – and indeed within our current Covid-dominated context (on the one hand) and the pre-scientific context of religion (on the other hand), it becomes increasingly difficult to imagine how it can remain possible to find something like a common issue, a shared problem, a kind of mutual concern or even a shared overlapping research trajectory that might benefit precisely from this envisaged interdisciplinary dialogue. Is it possible that ‘alone in this world’ could mean something different than what Van Huyssteen suggests?Intradisciplinary and/or interdisciplinary implications: How do we know that we can trust our viewpoints, and our religious convictions to constitute truth? Van Huyssteen develops the concept of a postfoundationalist epistemology in an attempt to justify theology’s integrity within the discourse with science. However, the author in this article argues that it has become increasingly difficult for systematic theology to find a shared overlapping research trajectory that might benefit this interdisciplinary dialogue.


2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Abdelkhaleq Maaroufi ◽  
Naoufal Assoufi ◽  
Mohamed Amine Essaoudi ◽  
Jamal Fatihi

Abstract Background The association of inflammatory myopathy and myasthenia gravis is a rarely described entity whose clinical presentation has always been intriguing because of the great clinical similarity between these two pathologies. The presence of a thymic pathology often explains this combination, whose mechanisms are very complex. Case presentation A 56-year-old woman of North African origin, was hospitalized to explore the Raynaud phenomenon associated with proximal muscle weakness, pain, and arthralgia. There was no rash, and neuromuscular examination had revealed proximal tetraparesis and mild neck weakness. Tendon reflexes were normal. There was no abnormal nail fold capillaroscopy. A significant titer of muscle enzymes had been shown on blood tests, and autoimmune screening for myositis-specific and myositis-associated autoantibodies was negative. Electromyography had shown a myopathic pattern, and muscle biopsy confirmed an inflammatory myopathy. Although steroids were introduced, the clinical course was unsatisfactory; ophthalmic and bulbar symptomatology appeared. The association of myasthenia gravis was confirmed by an elevated level of serum acetylcholine receptor. A chest computed tomography scan had identified a thymoma. Treated with prednisone, pyridostigmine, and thymectomy, the patient’s clinical and biological evolution was favorable. Conclusion This case illustrates an exceptional association of two entities and the difficulty encountered during their diagnosis and treatment. The management of these two diseases is different, so it is essential to recognize this concomitant presentation.


2021 ◽  
Author(s):  
Aniruddh D. Patel

A growing number of researchers across the sciences and humanities theorize that human musicality arose via an interplay of cultural invention and biological evolution, or “gene-culture coevolution.” This chapter offers ten concepts to help guide productive cross-disciplinary discussions on this topic. Such interactions across traditional disciplinary boundaries are needed to propel deep explorations of human musicality. These explorations are important for the study of human origins because musicality may prove to be a model system for exploring cognitive gene-culture coevolution, a process increasingly thought to be central to the evolution of the human mind.


2021 ◽  
pp. 45-72
Author(s):  
Steven Brown

This chapter examines both the biological and cultural evolution of the arts. Biological evolution of the arts deals with how humans evolved the species-specific capacities to create and appreciate artworks, while cultural evolution is about how artworks themselves, as cultural products, undergo changes in persistence over historical time and geographic location. The study of biological evolution includes both phylogenetic (or historical) and adaptationist (or Darwinian) approaches. The study of cultural evolution of the arts reveals the importance of a ‘creativity/aesthetics cycle’ in which the products of human creativity get appraised for their level of appeal by the aesthetic system, allowing them to either be transmitted to future generations or die out. This unification of creativity and aesthetics has far-reaching implications for both fields of study.


2021 ◽  
Author(s):  
Valentí Rull
Keyword(s):  

Is biology able to erect general laws and develop inductive predictions, as usual in physics or chemistry?


2021 ◽  
Author(s):  
Daniel Hasegan ◽  
Matt Deible ◽  
Christopher Earl ◽  
David D'Onofrio ◽  
Hananel Hazan ◽  
...  

Biological learning operates at multiple interlocking timescales, from long evolutionary stretches down to the relatively short time span of an individual's life. While each process has been simulated individually as a basic learning algorithm in the context of spiking neuronal networks (SNNs), the integration of the two has remained limited. In this study, we first train SNNs separately using individual model learning using spike-timing dependent reinforcement learning (STDP-RL) and evolutionary (EVOL) learning algorithms to solve the CartPole reinforcement learning (RL) control problem. We then develop an interleaved algorithm inspired by biological evolution that combines the EVOL and STDP-RL learning in sequence. We use the NEURON simulator with NetPyNE to create an SNN interfaced with the CartPole environment from OpenAI's Gym. In CartPole, the goal is to balance a vertical pole by moving left/right on a 1-D plane. Our SNN contains multiple populations of neurons organized in three layers: sensory layer, association/hidden layer, and motor layer, where neurons are connected by excitatory (AMPA/NMDA) and inhibitory (GABA) synapses. Association and motor layers contain one excitatory (E) population and two inhibitory (I) populations with different synaptic time constants. Each neuron is an event-based integrate-and-fire model with plastic connections between excitatory neurons. In our SNN, the environment activates sensory neurons tuned to specific features of the game state. We split the motor population into subsets representing each movement choice. The subset with more spiking over an interval determines the action. During STDP-RL, we supply intermediary evaluations (reward/punishment) of each action by judging the effectiveness of a move (e.g., moving the CartPole to a balanced position). During EVOL, updates consist of adding together many random perturbations of the connection weights. Each set of random perturbations is weighted by the total episodic reward it achieves when applied independently. We evaluate the performance of each algorithm after training and through the creation of sensory/motor action maps that delineate the network's transformation of sensory inputs into higher-order representations and eventual motor decisions. Both EVOL and STDP-RL training produce SNNs capable of moving the cart left and right and keeping the pole vertical. Compared to the STDP-RL and EVOL algorithms operating on their own, our interleaved training paradigm produced enhanced robustness in performance, with different strategies revealed through analysis of the sensory/motor mappings. Analysis of synaptic weight matrices also shows distributed vs clustered representations after the EVOL and STDP-RL algorithms, respectively. These weight differences also manifest as diffuse vs synchronized firing patterns. Our modeling opens up new capabilities for SNNs in RL and could serve as a testbed for neurobiologists aiming to understand multi-timescale learning mechanisms and dynamics in neuronal circuits.


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