Spread of new mutations through space

The terms population size and population density are often used interchangeably, when in fact they are quite different. When viewed in a spatial landscape, density is defined as the number of individuals within a square unit of distance, while population size is simply the total count of a population. In discrete population genetics models, the effective population size is known to influence the interaction between selection and random drift with selection playing a larger role in large populations while random drift has more influence in smaller populations. Using a spatially explicit simulation software we investigate how population density affects the flow of new mutations through a geographical space. Using population density, selectional advantage, and dispersal distributions, a model is developed to predict the speed at which the new allele will travel, obtaining more accurate results than current diffusion approximations provide. We note that the rate at which a neutral mutation spreads begins to decay over time while the rate of spread of an advantageous allele remains constant. We also show that new advantageous mutations spread faster in dense populations.

Closing a Bitcoin Trade Optimally under Partial Information: Performance Assessment of a Stochastic Disorder Model

The Bitcoin market exhibits characteristics of a market with pricing bubbles. The price is very volatile, and it inherits the risk of quickly increasing to a peak and decreasing from the peak even faster. In this context, it is vital for investors to close their long positions optimally. In this study, we investigate the performance of the partially observable digital-drift model of Ekström and Lindberg and the corresponding optimal exit strategy on a Bitcoin trade. In order to estimate the unknown intensity of the random drift change time, we refer to Bitcoin halving events, which are considered as pivotal events that push the price up. The out-of-sample performance analysis of the model yields returns values ranging between 9% and 1153%. We conclude that the return of the initiated Bitcoin momentum trades heavily depends on the entry date: the earlier we entered, the higher the expected return at the optimal exit time suggested by the model. Overall, to the extent of our analysis, the model provides a supporting framework for exit decisions, but is by far not the ultimate tool to succeed in every trade.

Hitting Times of Some Critical Events in RNA Origins of Life

Can a replicase be found in the vast sequence space by random drift? We partially answer this question through a proof-of-concept study of the times of occurrence (hitting times) of some critical events in the origins of life for low-dimensional RNA sequences using a mathematical model and stochastic simulation studies from Python software. We parameterize fitness and similarity landscapes for polymerases and study a replicating population of sequences (randomly) participating in template-directed polymerization. Under the ansatz of localization where sequence proximity correlates with spatial proximity of sequences, we find that, for a replicating population of sequences, the hitting and establishment of a high-fidelity replicator depends critically on the polymerase fitness and sequence (spatial) similarity landscapes and on sequence dimension. Probability of hitting is dominated by landscape curvature, whereas hitting time is dominated by sequence dimension. Surface chemistries, compartmentalization, and decay increase hitting times. Compartmentalization by vesicles reveals a trade-off between vesicle formation rate and replicative mass, suggesting that compartmentalization is necessary to ensure sufficient concentration of precursors. Metabolism is thought to be necessary to replication by supplying precursors of nucleobase synthesis. We suggest that the dynamics of the search for a high-fidelity replicase evolved mostly during the final period and, upon hitting, would have been followed by genomic adaptation of genes and to compartmentalization and metabolism, effecting degree-of-freedom gains of replication channel control over domain and state to ensure the fidelity and safe operations of the primordial genetic communication system of life.

A SINS/DVL/USBL Integrated Navigation and Positioning IoT System with Multiple Sources Fusion and Federated Kalman Filter

The navigation and positioning subsystem offers important position information for an autonomous underwater vehicle (AUV) system. It plays a crucial role during the underwater exploration and operations of AUV. Many scholars research underwater navigation and positioning. And many promising methods and systems were presented. However, as the diversity of ocean environment, the random drift of the gyroscope, error accumulation, the diversity of tasks, and other negative factors, the navigation and positioning result is uncertain and incredible. The accuracy, stability and robustness are not guaranteed, which can not meet the increasing application requirement. Therefore, we put forward a SINS/DVL/USBL integrated navigation and positioning IoT system with multiple resource fusion and a federated Kalman filter. In this method, we first present an improved SINS/DVL combined subsystem with filtering gain compensation strategy. The accuracy and stability of the navigation and position system can be enhanced. Secondly, We proposed a USBL positioning subsystem with the Kalman filtering acoustic signals to improve USBL positioning performance. Lastly, we present a federated Kalman Filter to fuse the positioning information from the SINS/DVL combined positioning subsystem and the USBL positioning subsystem. Through the above three methods, we can improve the positioning accuracy and robustness. Comprehensive simulation results indicated the feasibility and effectiveness of the proposed SINS/DVL/USBL integrated navigation and positioning system.

Microbiotic particles in water and soil, water-soil microbiota coalescences, and antimicrobial resistance

Bacterial organisms like surfaces. Water and soil contain a multiplicity of particulated material where bacterial populations and communities might attach. Microbiotic particles refers to any type of small particles (less than 2 mm) where bacteria (and other microbes) might attach, resulting in medium- long-term colonization. In this work, the interactions of bacterial organisms with microbiotic particles of the soil and water are reviewed. These particles include bacteria-bacteria aggregates, and aggregates with particles of fungi (particularly in the rhizosphere), protozoa, phytoplankton, zooplankton, biodetritus resulting from animal and vegetal decomposition, humus, mineral particles (clay, carbonates, silicates), and anthropogenic particles (including wastewater particles or microplastics). At they turn, these particles might interact and coalesce (as in the marine snow). Natural phenomena (from river flows to tides, tsunamis, currents, or heavy winds) and anthropogenic activity (such as agriculture, waste-water management, mining, soil-mass movement) favors interaction and merging between all these soil and water particles, and consequently coalescence of their bacterial-associated populations and communities, resulting in an enhancement of mixed-recombinant communities capable of genetic exchange, including antimicrobial resistance genes, particularly in antimicrobial-polluted environments. Particles also favor compartmentalization of bacterial populations favoring diversification and acquisition of mutational resistance by random drift. In general, microbial evolution is accelerated by the aggregation of microbiotic particles. We propose that the world spread of antimicrobial resistance might relate with the environmental dynamics of microbiotic particles, and discuss possible methods to reduce this problem influencing One Health and Planetary Health.

The evolution of color naming reflects pressure for efficiency: Evidence from the recent past

It has been proposed that semantic systems evolve under pressure for efficiency. This hypothesis has so far been supported largely indirectly, by synchronic cross-language comparison, rather than directly by diachronic data. Here, we directly test this hypothesis in the domain of color naming, by analyzing recent diachronic data from Nafaanra, a language of Ghana and Côte d'Ivoire, and comparing it with quantitative predictions derived from the mathematical theory of efficient data compression. We show that color naming in Nafaanra has changed over the past four decades while remaining near-optimally efficient, and that this outcome would be unlikely under a random drift process that maintains structured color categories without pressure for efficiency. To our knowledge, this finding provides the first direct evidence that color naming evolves under pressure for efficiency, supporting the hypothesis that efficiency shapes the evolution of the lexicon.

Evaluation of Matured Larval Weight and Larval Duration of New Breeding Lines of Bombyx mori L

We planned to conduct this study with the main aim to develop bivoltine breeds for our tropical climatic conditions by using silkworm breeds with known genetic backgrounds (KA, NB18 and PM) in various hybrid combinations and incorporating them over generations, followed by backcrossing and adequate selection of different generations with the objective of profitability and productivity. The isolated Bivoltin lines (R1 and R2) were reared with their parental races at different times of the year to evaluate their stability in the expression of commercial traits. For the present breeding program, the purebred Bivoltine Kalimpong-A (KA), which spin white oval cocoons, New Bivoltine18 (NB18) white cocoons with rotating dumbbells and Multivoltine Pure Mysore (PM), the yellow pointed cocoons of the mulberry silkworm Bombyx mori L., Selected. One-way and three-way crosses were made using the above three breeds. The first single cross comprised KA females and PM males. The second unique cross comprised NB18 females and PM males. Selection was performed at the egg, larva, pupal, and cocoon stages over the course to determine the desired traits. The offspring of F from the respective crosses were backcrossed with their respective bivoltine males to improve commercial traits. Heterosis in the F1 generations of crosses, including NB18 and PM, was determined by the mean score of the parents (MPV) and the best score of the parents (BPV). A significant test for heterosis was performed using a standard ANOVA table. Based on the results of our study, it was found that the performance of the characters, viz. The weight of mature larvae and the duration of the larvae over generations do not simply increase or decrease regularly, but fluctuate irregularly. The reason for this variation may be due to random genetic drift, sampling errors in estimating generational means, selection pressures, and environmental factors. Therefore, inbreeding variations due to random drift and sampling errors could be reduced by increasing the number sampled and selected.

Оцінка впливу похибок БІНС, яка побудована на MEMS-компонентах, на точність виведення ракети-носія надлегкого класу

The object of the article is the movement of an ultra-light class liquid-propellant launch vehicle in near-earth space. The subject of the research is the accuracy of launching a spacecraft by a launch vehicle. The article studies the effect of errors in the instruments of a strap-down inertial navigation system built with the use of MEMS sensors on the accuracy of launching a spacecraft into low-earth orbits with an altitude of up to 450 km for two modes of operation: with and without a satellite navigation system. Tasks: to identify the determining disturbing factors, to determine the influence of instrument errors on the trajectory tube, to determine the influence of instrument errors on the insertion accuracy, to perform a comparative analysis of the accuracy characteristics obtained for two modes of operation of the navigation system. Methods used analysis, synthesis, analogy, comparison, factor analysis, statistical modeling, statistical processing of modeling results. Results: a set of defining disturbing factors was revealed, the dependencies of the trajectory tubes on the altitude of the target orbit and flight time were obtained, the dependencies of the limiting deviations of the parameters of the spacecraft's orbit at the time of separation from the launch vehicle on the altitude of the target orbit were obtained. Conclusions. 1. It is shown that the determining perturbing factors are the zero drift of the gyroscope from launch to launch and the zero random drift of the gyroscope. 2. It was determined that the value of the trajectory tube monotonically expands on time and the height of the target orbit. Maximum deviations of the current position and absolute speed in the mode without using a satellite navigation system do not exceed 115 km and 140 m/s. For the mode using a satellite navigation system, these values do not exceed 140 m and 1.5 m/s. 3. It was revealed that the maximum deviations of the parameters of the spacecraft's orbit in the mode with the use of a satellite navigation system do not exceed 27 km in height, 1.8o in inclination, 4.5x10-4 in eccentricity, and 2.7o for the longitude of the ascending node. For the mode with a satellite navigation system - in height - 2.6 km, in inclination and longitude of the ascending node - 0.0003о, in eccentricity - 3.5x10-4. 4. Generally, the use of a satellite navigation system narrows the trajectory tube by twice, and the accuracy increases to four times, depending on the orbital parameters.

Fast and strong amplifiers of natural selection

Selection and random drift determine the probability that novel mutations fixate in a population. Population structure is known to affect the dynamics of the evolutionary process. Amplifiers of selection are population structures that increase the fixation probability of beneficial mutants compared to well-mixed populations. Over the past 15 years, extensive research has produced remarkable structures called strong amplifiers which guarantee that every beneficial mutation fixates with high probability. But strong amplification has come at the cost of considerably delaying the fixation event, which can slow down the overall rate of evolution. However, the precise relationship between fixation probability and time has remained elusive. Here we characterize the slowdown effect of strong amplification. First, we prove that all strong amplifiers must delay the fixation event at least to some extent. Second, we construct strong amplifiers that delay the fixation event only marginally as compared to the well-mixed populations. Our results thus establish a tight relationship between fixation probability and time: Strong amplification always comes at a cost of a slowdown, but more than a marginal slowdown is not needed.