140 Results Found

In this paper, a stochastic continuous-time Markov chain (CTMC) model is developed and analyzed to explore the dynamics of cholera. The multitype branching process is used to compute a stochastic threshold for the CTMC model. Latin hypercube sampling...

Classical branching-process theory, developed by Galton and Watson in the nineteenth century and later refined by Fisher and Haldane, provides the formal framework for quantifying the fate of new mutants, new viral and bacterial pathogens, new coloni...

We show that a class of downwardly skip-free processes can be regarded as the Siegmund dual of upwardly skip-free processes, which have been extensively studied in the literature. For such downwardly skip-free processes, using the duality method and...

We explore the most probable phase portrait (MPPP) of a stochastic single-species model incorporating the Allee effect by utilizing the nonlocal Fokker–Planck equation (FPE). This stochastic model incorporates both non-Gaussian and Gaussian noi...

The neutron survival probability (and related quantities including probabilities of extinction and initiation) is a central element of the broader stochastic theory of neutron populations and finds application in fields including reactor start-up, an...

The basic reproduction number $R_0$ is a concept which originated in population dynamics, mathematical epidemiology, and ecology and is closely related to the mean number of children in branching processes (reflecting the fact that the phenomena of inte...

The classical Lotka–Volterra predator–prey model is globally stable and uniformly persistent. However, in real-life biosystems, the extinction of species due to stochastic effects is possible and may occur if the magnitudes of the stochas...

We consider the effect of global warming on the coupled plankton-oxygen dynamics in the ocean. The net oxygen production by phytoplankton is known to depend on the water temperature and hence can be disrupted by warming. We address this issue theoret...

Extinction forecasting is one of the most important and challenging areas of conservation biology. Overestimates of extinction rates or the extinction risk of a particular species instigate accusations of hype and overblown conservation rhetoric. Con...

The Eurasian Black Vulture is a globally threatened raptor that in Southeast Europe only occurs in an isolated population in Greece. We examined the population viability for the species under demographic fluctuations and conservation scenarios. The c...

Commutation failure is still one of the most common faults in LCC-UHVDC (line commutated converter-based, ultra-high voltage direct current) systems, and if the inverter side, extinction angle, and rectification value remain constant during the fault...

A pathogen can infect multiple hosts. For example, zoonotic diseases like rabies often colonize both humans and animals. Meanwhile, a single host can sometimes be infected with many pathogens, such as malaria and meningitis. Therefore, we studied two...

Poyang Lake in China is the most critical habitat and final refuge for the Yangtze finless porpoise (Neophocaena asiaeorientalis), YFP. In 2022, its population reached approximately 492 individuals, an increase of 35 from the 457 individuals recorded...

We study the rumor propagation model with regime switching considering both colored and white noises. Firstly, by constructing suitable Lyapunov functions, the sufficient conditions for ergodic stationary distribution and extinction are obtained. The...

Malaria remains a major public health burden in South-East Asia and Africa. Mathematical models of within-host infection dynamics and drug action, developed in support of malaria elimination initiatives, have significantly advanced our understanding...

In this paper, experimental and numerical analyses are performed with a Rapid Compression and Expansion Machine (RCEM) equipped with a passive pre-chamber (PC) and fueled with premixed stoichiometric air/methane mixture to replicate engine-like condi...

Since November 2019, each country in the world has been affected by COVID-19, which has claimed more than four million lives. As an infectious disease, COVID-19 has a stronger transmission power and faster propagation speed. In fact, environmental no...

One third of missing mammal species thought to be extinct have been rediscovered. Determining extinction correctly, without misinterpreting negative evidence, is difficult and takes significant effort, especially for small, cryptic species. The Morro...

Understanding of the trait-based ecology of the periphytic algal community has increased in the last decade. However, the relationship between their functional diversity and ecosystem functions, such as primary production, has been speculated on, but...

The chronology of observations of two extinct flightless birds in 17th century Mauritius, the dodo (Raphus cucullatus) and the red hen (Aphanapteryx bonasia), and what names or descriptions were used for them, is re-examined. It was concluded that th...

A continuous-time network evolution model is considered. The evolution of the network is based on 2- and 3-interactions. 2-interactions are described by edges, and 3-interactions are described by triangles. The evolution of the edges and triangles is...

The paper develops a coarse-grained framework for computing mean extinction times in multi-metastable systems modeled as one-step continuous-time Markov chains with an absorbing state. At the microscopic level, backward equations on finite corridors...

Vampire bats likely first appeared in South America in the early Miocene (~20 Ma) and evolved to feed upon the blood of native South American mammals of medium to large body size, in particular, xenarthrans–ground sloths, armadillos, pampathere...

As the classic branching process, the Galton-Watson process has obtained intensive attentions in the past decades. However, this model has two idealized assumptions–discrete states and time-homogeneity. In the present paper, we consider a branc...

Type Ia supernovae are used as fundamental probes of the cosmological parameters, based on a tight empirical relation between their peak luminosity and the width of their light curve. However, it has been recognized that SNe Ia are not “standar...

It is well known that the evolution of natural populations is almost inevitably disturbed by various environmental factors. Various experiments have shown that the growth of phytoplankton might be affected by nutrient availability, water temperature,...

This article presents a genetic algorithm modification inspired by events related to great extinctions. The main objective of the modification was to minimize the number of objective function solutions until the minimum for the function was establish...

In running waters, under climate change conditions, the combined effect of water warming and decreasing flow rates may encourage colonisation by invasive cool and warm-water fish species. The aim of the study was to analyze the potential climate chan...

A vital component of small population management in captivity is forecasting future population trends. Until recently, little was known about the demographic structure of the recently retired captive former biomedical research chimpanzee population (...

The Mediterranean monk seal (Monachus monachus) is one of the most endangered marine mammals in the world. This species has been threatened since ancient times by human activities and currently amounts to approximately 700 individuals distributed in...

This study develops a stochastic SIQR epidemic model with mean-reverting Ornstein–Uhlenbeck (OU) processes for both transmission rate $\beta \left(t\right)$ and quarantine release rate $k\left(t\right)$; this is distinct from existing non-white-noise stochastic epidemic...

Climate changes will lead to a worsening of the ecological conditions, in terms of hydrological instability and rising water temperatures, of the Mediterranean rivers. Freshwater fishes inhabiting this area can be threatened in the near future by acc...

The internal growth patterns and surface micromorphology of diamonds provide a record of their multi-stage evolution, from initial formation within the mantle to their eventual ascent to the Earth’s surface via deeply derived kimberlite magmas....

Starting four decades ago, studies have examined the ecology and evolutionary dynamics of populations and species using short mitochondrial DNA fragments and stable isotopes. Through technological and analytical advances, the methods and biomolecules...

The Adelaide-Mt Lofty Region of South Australia is an exemplar, in microcosm, of the issues confronting biodiversity conservation in a world of increasing population and a drying, fire-prone environment. At just 0.1% of Australia’s terrestrial land m...

Forty-one species in 20 genera of hygrophilous weevils belonging to Brentidae and Curculionidae, associated with inland aquatic habitats, have been recorded recently from Israel, eight of them for the first time. Thirty-four species are extant, while...

Here, we investigate whether bone microanatomy can be used to infer the locomotion mode (cursorial vs. graviportal) of large terrestrial birds. We also reexamine, or describe for the first time, the bone histology of several large extant and extinct...

Urban ecosystems are carrying an extinction debt. Mitigating this debt will require the development of a predictive framework that improves our understanding of the factors causing decline of native biodiversity in urban areas. I argue that nitrogen...

Numerical modeling was conducted to study the capture of particles diffusing in porous media with traps. The pores are cylindrical in shape, and the traps are randomly distributed along the cylindrical surfaces of the pores. The dynamics of particle...

Passive microwave measurements from satellites have been used to identify the signature of hail in intense thunderstorms. The scattering signal of hailstones is typically observed as a strong depression of upwelling brightness temperatures from the c...

The Chinese goral (Naemorhedus griseus) is identified as a vulnerable species on the Red List of China’s Biodiversity and listed as a national second-class key protected wild animal in China. It is a representative flagship ungulate in Beijing....

Humans arrived in the Patagonia region of southern South America in the late Pleistocene period, ca. 15,000 years ago. A few centuries later, during a period of rapid warming, the megafauna went extinct in Patagonia, as well as some smaller species,...

A conceptual model based on the balance of energy in a system composed of a burning cigarette, ambient flow and a porous fuel bed is proposed to study the burning of a single cigarette and the process of fuel bed dehydration, pyrolysis and its eventu...

The atmospheric molecular number density can be obtained from atmospheric temperature and pressure profiles and is a significant input parameter for the inversion of lidar measurements. When measurements of vertical profiles of temperature and pressu...

In this article, we analyze a second-order stochastic SEIR epidemic model with latent infectious and susceptible populations isolated at home. Firstly, by putting forward a novel inequality, we provide a criterion for the presence of an ergodic stati...

Lifetime reproductive output (LRO), also called lifetime reproductive success (LRS) is often described by its mean (total fertility rate or net reproductive rate), but it is in fact highly variable among individuals and often positively skewed. Sever...

The introduction of alien species may pose an enormous threat to indigenous flora and fauna. Among introduced animals, probably the most destructive to the natural environment are mammals. This is true at least in regard to the Afrotropical Region (s...

A century ago, wolves ranged throughout Croatia but were eradicated from Slavonia—a region that could serve as a crucial corridor connecting the Carpathian and Dinaric–Balkan wolf populations. Such a corridor would promote genetic exchang...

High-quality measurements of air quality are the highest priority for understanding widespread air pollution. Visibility has been widely suggested to be a good alternative to PM_2.5 concentration as a measure. In this study, the similarities and diffe...

The ability of microorganisms to colonise and display an intracellular lifestyle within a host body increases their fitness to survive and avoid extinction. This host–pathogen association drives microbial evolution, as such organisms are under...