Transposon Extermination Reveals Their Adaptive Fitness Contribution

Transposable Elements are molecular parasites that persist in their host genome by generating new copies to outpace natural selection. Here we measure the parameters governing the copy number dynamics of the fission yeast Tf2 retrotransposons, using experimental and natural populations and a strain where all Tf2 copies are removed. Natural population genomes display active and persistent Tf2 colonies, but in the absence of selection mitotic recombination deletes Tf2 elements at rates that far exceed transposition. We show that Tf2 elements provide a fitness contribution to their host by dynamically rewiring the transcriptional response to metabolic stress. Therefore, Tf2 elements exhibit a mutualistic rather than parasitic behavior toward their host.

Seasonal and multiannual dynamics of sedentary species populations of hunting interest

The aim of the research was to study the number dynamics of the populations of dominant sedentary species of hunting interest as a theoretical context in arguing sustainable measures for the management of economic interest fauna. The studies between 2000-2021 shows that after a period of depression in the populations of sedentary species of hunting interest in 2004-2012 there is an increase from 2016-2017 till present of reproductive stocks in all studied species on average by 95%. The losses in the cold period of the year varied depending on the climatic conditions of the cold period of the year, as well as the age structure at the end of the reproductive period: for the hare between 14% and 30%, with an average of 23%; in grey partridge from 56% to 71% and in pheasant they fluctuate between 48% and 56% of the autumn number, being lower in warm winters (37%). Analyzing the dynamics of annual increases in sedentary small game species in different climatic conditions, it was found that arid conditions during nesting and offspring growth, decrease annual increases by 143% in pheasants, 122% in hares, and only 74% in partridges, which is a species less dependent on aridizations in the vegetative period.

Atto-Foxes and Other Minutiae

This paper addresses the problem of extinction in continuous models of population dynamics associated with small numbers of individuals. We begin with an extended discussion of extinction in the particular case of a stochastic logistic model, and how it relates to the corresponding continuous model. Two examples of ‘small number dynamics’ are then considered. The first is what Mollison calls the ‘atto-fox’ problem (in a model of fox rabies), referring to the problematic theoretical occurrence of a predicted rabid fox density of $$10^{-18}$$ 10 - 18 (atto-) per square kilometre. The second is how the production of large numbers of eggs by an individual can reliably lead to the eventual survival of a handful of adults, as it would seem that extinction then becomes a likely possibility. We describe the occurrence of the atto-fox problem in other contexts, such as the microbial ‘yocto-cell’ problem, and we suggest that the modelling resolution is to allow for the existence of a reservoir for the extinctively challenged individuals. This is functionally similar to the concept of a ‘refuge’ in predator–prey systems and represents a state for the individuals in which they are immune from destruction. For what I call the ‘frogspawn’ problem, where only a few individuals survive to adulthood from a large number of eggs, we provide a simple explanation based on a Holling type 3 response and elaborate it by means of a suitable nonlinear age-structured model.

The Seasonal Variability of the Ocean Energy Cycle From a Quasi-Geostrophic Double Gyre Ensemble

With the advent of submesoscale O(1km) permitting basin-scale ocean simulations, the seasonality in the mesoscale O(50km) eddies with kinetic energies peaking in summer has been commonly attributed to submesoscale eddies feeding back onto the mesoscale via an inverse energy cascade under the constraint of stratification and Earth’s rotation. In contrast, by running a 101-member, seasonally forced, three-layer quasi-geostrophic (QG) ensemble configured to represent an idealized double-gyre system of the subtropical and subpolar basin, we find that the mesoscale kinetic energy shows a seasonality consistent with the summer peak without resolving the submesoscales; by definition, a QG model only resolves small Rossby number dynamics (O(Ro)≪1) while as submesoscale dynamics are associated with O(Ro)∼1. Here, by quantifying the Lorenz cycle of the mean and eddy energy, defined as the ensemble mean and fluctuations about the mean respectively, we propose a different mechanism from the inverse energy cascade by which the stabilization and strengthening of the western-boundary current during summer due to increased stratification leads to a shedding of stronger mesoscale eddies from the separated jet. Conversely, the opposite occurs during the winter; the separated jet destablizes and results in overall lower mean and eddy kinetic energies despite the domain being more susceptible to baroclinic instability from weaker stratification.

The Seasonal Variability of the Ocean Energy Cycle From a Quasi-Geostrophic Double Gyre Ensemble

With the advent of submesoscale O(1km) permitting basin-scale ocean simulations, the seasonality in the mesoscale O(50km) eddies with kinetic energies peaking in summer has been commonly attributed to submesoscale eddies feeding back onto the mesoscale via an inverse energy cascade under the constraint of stratification and Earth’s rotation. In contrast, by running a 101-member, seasonally forced, three-layer quasi-geostrophic (QG) ensemble configured to represent an idealized double-gyre system of the subtropical and subpolar basin, we find that the mesoscale kinetic energy shows a seasonality consistent with the summer peak without resolving the submesoscales; by definition, a QG model only resolves small Rossby number dynamics (O(Ro)≪1) while as submesoscale dynamics are associated with O(Ro)∼1. Here, by quantifying the Lorenz cycle of the mean and eddy energy, defined as the ensemble mean and fluctuations about the mean respectively, we propose a different mechanism from the inverse energy cascade by which the stabilization and strengthening of the western-boundary current during summer due to increased stratification leads to a shedding of stronger mesoscale eddies from the separated jet. Conversely, the opposite occurs during the winter; the separated jet destablizes and results in overall lower mean and eddy kinetic energies despite the domain being more susceptible to baroclinic instability from weaker stratification.

Dynamics of scientific personnel in the transition from the USSR to the Russian Federation

The article analyzes dynamics of the number of scientific personnel during the transition from the USSR (RSFSR) to the Russian Federation. The method of analysis is proposed which is based not on the dynamics of the age groups but on the analysis of scientists amount dynamics of certain years of birth. This approach allows to identify the logic of different ages scientists behavior in the crisis and their reaction on economy changes in the 90s of the last century. Both the total number of researchers and the dynamics of age distributions during the period of fast changes (1990–1998) and after 1998 were analyzed. It is shown that the dynamics of the scientists number in the post-Soviet period was largely determined by the age peaks of the researchers distribution formed in the USSR in the 60-70s. Currently, the effect of these peaks has expired and the age distribution is more in line with the general age distribution of the population. Forecasts of the researchers number dynamics in Russia in the near future are given.

Number dynamics of the moose, wolf, and bear in the Kemerovo region from the second half of the 20th century to the beginning of the 21st century

Представлен анализ динамики численности лося, медведя и волка на территории Кемеровской области (Кузбасса) за последние 70 лет. Максимальных значений численность лося достигала в 1976-1979 гг. (7000 особей), минимальных - в 1994 г. (1850 особей). В настоящее время количество лосей на территории Кемеровской области превысило 5,0 тыс. особей с тенденцией к повышению. Количество медведей в Кемеровской области на протяжении всего исследуемого периода непрерывно возрастает с 300-400 особей в начале 1960-х гг. до 3,0-3,1 тыс. в 2017-2019 гг. Волк на территории Кузбасса находится под жёстким антропогенным прессом. Максимальное количество волков в 400-450 голов отмечалось в 1994-1996 гг., в настоящее время этот хищник практически истреблён, периодически отмечаются заходы 2-7 зверей из сопредельных регионов в зимнее время. Проанализированы основные факторы, влияющие на численность лося: охота, хищничество волка и медведя, качество работы органов госохотнадзора. Показано, что в Кемеровской области количество лося, волка и медведя зависит, в первую очередь, от охотхозяйственной деятельности. Достоверная отрицательная корреляция лося с численностью медведя и волка выявляется только на отдельных временных отрезках, когда она налагается на отрицательное антропогенное воздействие. The analysis of the dynamics of the number of moose, bear, and wolf in the territory of the Kemerovo region (Kuzbass) over the past 70 years is presented. The maximum number of moose reached in 1976-1979 (7000 individuals), the minimum - in 1994 (1850 individuals). Currently, the number of moose in the Kemerovo Region has exceeded 5.0 thousand individuals with an upward trend. The number of bears in the Kemerovo region throughout the study period is continuously increasing from 300-400 individuals in the early 1960s up to 3.0-3.1 thousand in 2017-2019. The wolf on the territory of Kuzbass is under severe anthropogenic pressure. The maximum number of wolves of 400-450 animals was observed in 1994-1996. At present, this predator is almost exterminated. Only 2-7 animals from neighboring regions are periodically noticed in winter. The main factors affecting the moose abundance are analyzed: hunting, predation of a wolf and a bear, and the quality of work of State Hunting Surveillance bodies. The number of moose, wolf and bear in Kemerovo Region depends mainly on hunting activities. A reliable negative correlation of the moose with the number of bears and wolves is detected only in some intervals when it is imposed on a negative anthropogenic impact.

Modified SIR-model applied to covid-19, similarity solutions and projections to further development

The SIR-model is adapted to the covid-19 pandemic through a modification that consists in making the basic reproduction number variable. Independent of it, another reproduction number is introduced, which is defined similarly to the usual net reproduction number. Due to its simple analytic form, it enables a clear interpretation for all values. A further parameter, provisionally called acceleration parameter, is introduced and applied, which enables a more differentiated characterization of the infection number dynamics. By a variable transformation the 3 equations of the modified SIR-model can be reduced to 2. The latter are solved up to ordinary integrations. The solutions are evaluated for current situations, yielding a pretty good match with the data reported. Encouraged by this, a variety of possible future developments is examined, including linear and exponential growth of the infection numbers as well as sub- and super-exponential growth. In particular, the behavior of the two reproduction numbers and the acceleration parameter is studied, which in some cases leads to surprising results. With regard to the number of unreported infections it is shown, that from the solution for a special one solutions for others can be derived by similarity transformations.