We examined the sequence variation of mitochondrial DNA control region and cytochrome b gene of the house mouse (Mus musculus sensu lato) drawn from ca. 200 localities, with 286 new samples drawn ...primarily from previously unsampled portions of their Eurasian distribution and with the objective of further clarifying evolutionary episodes of this species before and after the onset of human-mediated long-distance dispersals. Phylogenetic analysis of the expanded data detected five equally distinct clades, with geographic ranges of northern Eurasia (musculus, MUS), India and Southeast Asia (castaneus, CAS), Nepal (unspecified, NEP), western Europe (domesticus, DOM) and Yemen (gentilulus). Our results confirm previous suggestions of Southwestern Asia as the likely place of origin of M. musculus and the region of Iran, Afghanistan, Pakistan, and northern India, specifically as the ancestral homeland of CAS. The divergence of the subspecies lineages and of internal sublineage differentiation within CAS were estimated to be 0.37-0.47 and 0.14-0.23 million years ago (mya), respectively, assuming a split of M. musculus and Mus spretus at 1.7 mya. Of the four CAS sublineages detected, only one extends to eastern parts of India, Southeast Asia, Indonesia, Philippines, South China, Northeast China, Primorye, Sakhalin and Japan, implying a dramatic range expansion of CAS out of its homeland during an evolutionary short time, perhaps associated with the spread of agricultural practices. Multiple and non-coincident eastward dispersal events of MUS sublineages to distant geographic areas, such as northern China, Russia and Korea, are inferred, with the possibility of several different routes.
The paper is devoted to study of interface matter transfer during evaporation and condensation. At the beginning different definitions of evaporation and condensation coefficients are analyzed. Then ...brief history of study development about mass flux density determination at evaporation and condensation is presented. The possibilities of molecular dynamics simulation concerning these processes are discussed. Then interpretation of Furukawa and Murakami (1999)
16 experimental data about determination of evaporation and condensation coefficients on helium vapor and its condensed superfluid phase (HeII) interface has been done. As a resume conclusion is made that at weak evaporation of high thermal conductivity matters as evaporation and as condensation coefficients are close to unit approximately.
•The Boltzmann kinetic equation by the moment method is solved for the problem of the film boiling on a spherical heating surface.•The analytical expressions for the heat flux is obtained.•The ...obtained nonlinear relation is transformed into the corresponding flat heating surface formula.•The measured and calculated data on the thin films thickness are in good agreement.
Special nonlinear relations can determine the heat flux in a film boiling on a spherical heating surface. They are obtained by transforming the system of moment conservation equations derived from the Boltzmann kinetic equation based on a two-sided Maxwellian distribution approximation. We solve the Boltzmann kinetic equation by the moment method elaborating on the approach of L. Lees for describing thermal conductivity through a gas-filled spherical gap between two impermeable interfaces. The obtained analytical expressions for the heat flux can be used for any value of the Knudsen number.
Abstract
The calculation of the recovery heat flux density is considered for superfluid helium boiling on the cylindrical heater inside porous structure. System of equations is based on the methods ...of continuum mechanics and molecular kinetic theory. The new type of boundary condition on the vapor-liquid interface based on the two-fluid model is formulated. Heat transfer in a free liquid is described by the Gorter-Mellink semi-empirical theory. Inside the porous structure the processes is discussed by the two-fluid model and filtration equation. Experimental data on the boiling of superfluid helium inside the porous structure are interpreted based on the formulated mathematical model. The qualitative and in some cases quantitative agreement between the calculated and experimental values of the recovery heat flux were obtained in the considered range of parameters
Occurrence of copy number variation (CNV) of gene loci is important in the adaptation of species and populations to their environments. High copy numbers of mammalian genes encoding the digestive ...enzyme amylase, which plays a role in starch digestion, have been associated with adaptation to high‐starch foods. Here, we investigated CNV in the pancreatic amylase gene (AMY2) in Eurasian badgers (Meles species) and related taxa using real‐time quantitative PCR. We found that Meles anakuma and M. meles, as well as the other mustelids Mustela sibirica, Martes melampus and Martes zibellina, had only one copy of the AMY2 locus, whereas in Meles leucurus the copy number varied between one and four. The AMY2 copy number also varied significantly among M. leucurus populations. This suggests that M. leucurus is better adapted to a diet rich in starch and/or glycogen than its congeners. As Meles spp. are basically omnivorous but favor a carnivoran diet, for example, earthworms and amphibians, we speculate that the CNV is related to the dearth of animal food in the range of M. leucurus, which enforces a more vegetal diet. This in turn would favor more efficient digestion of dietary starch, which could be achieved by increasing the copy number of AMY2 .
The copy number of the pancreatic amylase gene (AMY2) locus was investigated in Eurasian badgers (Meles species) and related taxa by using real‐time quantitative PCR. Then it was found that Meles anakuma and M. meles, as well as the other mustelids Mustela sibirica, Martes melampus and Martes zibellina, had only one copy of the AMY2 locus, whereas in Meles leucurus the copy number varied between one and four. The AMY2 copy number also varied significantly among M. leucurus populations. This suggests that M. leucurus is better adapted to a diet rich in starch and/or glycogen than its congeners.
A comparative overview of decentralized data storages of different types is presented. It is shown that, although they have some common properties typical of all peer-to-peer (P2P) networks, the ...tasks they solve and, hence, the technologies used to construct storage facilities of different types are significantly different.
•A conjugate approximate method that accounts for the peculiarities of atom–interface interactions was developed.•In this method, the Boltzmann kinetic equation is numerically solved for the vapor ...phase.•The condensate matter and liquid–vapor transition layer are investigated through molecular kinetics and dense medium statistical mechanics.•A favorable modeled-versus-experimental comparison of the saturation lines and possibility to obtain the solutions of an evaporation–condensation problem evidenced the validity of the proposed method.
This paper presents a conjugate approximate method for solving transfer problems in a two-phase (condensate–vapor) system that accounts for the peculiarities of atom–interface interactions and obtains a distribution function for the evaporated and reflected atoms. In this method, the Boltzmann kinetic equation is numerically solved for the vapor phase. The condensate matter and liquid–vapor transition layer are investigated through molecular kinetics and dense medium statistical mechanics. Finally, the proposed approach is validated by solving equilibrium saturation vapor–liquid lines of different substances as well as a nonsteady evaporation–condensation problem and by comparing the results with experimental data.
•The values of the recovery heat flux at superfluid helium boiling is differ from immersion depth and liquid temperature.•There is no influence permeability on the recovery heat flux at backfill ...particles diameters greater than 240 µm.•The calculated results are in satisfactory agreement with the experiment.•Porous insert has a significant effect on the interface dynamics\ (amplitude, frequency, stationary vapor film).
The paper presents experimental data on the recovery heat flux during the boiling of superfluid helium (He II) on a flat heater located inside a U-shaped channel. The lower part of the channel is filled with monodisperse porous backfill. The paper includes information on the experimental cell, the data processing and synchronization technique, and the results of experiments conducted at different heater immersion depths and liquid temperatures. The paper presents also a mathematical description of heat transfer processes in superfluid helium for confined conditions. The calculated values are compared with experimental data. The effect of the porous backfill permeability on the recovery heat flux, including the case of a free channel is discussed. It is demonstrated that the increase in the heat flux in the channel initiates oscillations of the phase interface.
Abstract
Evaporation and condensation processes are intensely used in various fields of technology. Efforts to understand the features of film boiling of various liquids, primarily superfluid helium, ...inevitably lead to studying the strongly nonequilibrium processes of heat transfer from the heating surface through the vapor to the condensed phase. Theoretical studies of evaporation and condensation of single-component substances are briefly reviewed. Corresponding experimental data are analyzed and compared with calculations. We explore the important, yet unresolved and actively studied problems of condensation from vapor–gas media, the formulation of boundary conditions, and the application of molecular dynamics and kinetic theory methods to the study of heat and mass transfer at phase interfaces.
Experimental data on the study of boiling of superfluid helium (helium II) on a cylindrical heater inside a porous structure are considered. Based on an analysis of video recordings, the heat and ...mass transfer modes characterized by significant modification of the shape of the phase interface are classified. The values of heat fluxes and heater temperatures are presented, and the degree of nonequilibrium of the corresponding transfer processes is assessed.
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