A stochastic SIRI epidemic model with relapse and media coverage

This work is devoted to investigate the existence and uniqueness of a global positive solution for a stochastic epidemic model with relapse and media coverage. We also study the dynamical properties of the solution around both disease-free and endemic equilibria points of the deterministic model. Furthermore, we show the existence of a stationary distribution. Numerical simulations are presented to confirm the theoretical results.Fondo Europeo de Desarrollo RegionalMinisterio de Economía y CompetitividadConsejería de Innovación, Ciencia y Empresa (Junta de Andalucía)Faculty of Sciences (Ibn Tofail University

A stochastic SIRI epidemic model with Lévy noise

Some diseases such as herpes, bovine and human tuberculosis exhibit relapse in which the recovered individuals do not acquit permanent immunity but return to infectious class. Such diseases are modeled by SIRI models. In this paper, we establish the existence of a unique global positive solution for a stochastic epidemic model with relapse and jumps. We also investigate the dynamic properties of the solution around both disease-free and endemic equilibria points of the deterministic model. Furthermore, we present some numerical results to support the theoretical work

Analysis of a stochastic distributed delay epidemic model with relapse and Gamma distribution kernel

In this work, we investigate a stochastic epidemic model with relapse and distributed delay. First, we prove that our model possesses and unique global positive solution. Next, by means of the Lyapunov method, we determine some sufficient criteria for the extinction of the disease and its persistence. In addition, we establish the existence of a unique stationary distribution to our model. Finally, we provide some numerical simulations for the stochastic model to assist and show the applicability and efficiency of our results.Ministerio de Ciencia, Innovación y Universidades (MICINN). EspañaEuropean Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER

Wildfire yields a distinct turnover of the beetle community in a semi-natural pine forest in northern Sweden

Background Fires have been an important natural disturbance and pervasive evolutionary force in the boreal biome. Yet, fire suppression has made forest fires rare in the managed landscapes in Fennoscandia, causing significant habitat loss for saproxylic species such as polypores and insects. To better understand how the beetle community changes (species turnover) after a wildfire in a landscape with intense fire suppression, we monitored beetles with flight intercept traps the first 3 years as well as 12 years after a large wildfire in a national park in northern Sweden (a control/unburnt area was set up for the last year of sampling). Results Species composition changed significantly among all studied years with a continuous turnover of species following the wildfire. The indicator species analysis showed that year 1 post-fire was mostly associated with cambium consumers and also the pyrophilous speciesBatrisodes hubenthali. Year 2 was the most abundant and species-rich year, withTomicus piniperdaas the most important indicator species. The indicator species year 3 were mostly secondary successional species, fungivores, and predators and were characterized by lower species diversity. Year 12 had higher diversity compared with year 3 but lower species richness and abundance. A control area was established during year 12 post-fire, and our analyses showed that the control area and burned area differed in species composition suggesting that the beetle community needs longer than 12 years to recover even after a low-intensive ground fire. Conclusion The wildfire area hosted several red-listed and fire-dependent species suggesting that after a century of landscape-level fire suppression in a semi-natural area, the reintroduction of fire benefits rare and pyrophilous species and still impacts species composition after 12 years. This study implies that fire has long-lasting effects on high latitudes and that prescribed burning has the potential to benefit biodiversity over decades in these landscapes while also highlighting the value of considering the whole species community and not only monitoring abundance and richness to assess biodiversity after management actions

Occurrence of flat bugs (Heteroptera: Aradidae) in burned and unburned forests

The goal of this study was to determine the effect of fire on flat bug diversity and abundance in coniferous and mixed forests in interior Alaska. Eighty individuals, of which 78 in the burned areas and two in the control areas, of six aradid species were collected: Aradus abbas (Bergroth), A. funestus (Bergroth), A. lugubris (Fallén), A. signaticornis (Sahlberg), A. tuberculifer (Kirby) and Aneurus simplex (Uhler). Generally, all flat bug species were more abundant in the burned areas than in control areas with statistically significant differences for four of the six species and for pooled nymphs. Habitat preferences and potential mechanisms connecting mycophagy and pyrophagy are discussed

Till minne av Stig Lundberg (1928–2020)

Jägmästare Stig Lundberg föddes den 12:e augusti 1928 och växte upp i Luleå. Som son till jägmästare Hjalmar Lundberg berättade Stig för oss om hur han som en liten gosse på realskolan i Luleå 1939 skickades ut med en burk för att samla skalbaggar åt läraren. När Stig återvände med en skalbagge i burken hände det att läraren, efter att exemplaret studerats med lupp, stoppade burken i egen ficka med orden: “Den behåller jag!”. Stig bestämde sig redan då att han som vuxen skulle göra detsamma som läraren, den legendariske jordlöparspecialisten Carl H. Lindroth, gå omkring med en lupp runt halsen och samla in intressanta skalbaggar. Och så kom det också att bli under mer än sextio år

Kinetics of substrate oxidation and hydrogen peroxide production by Mycoplasma mycoides subsp. mycoides Large Colony (LC) type and Mycoplasma mycoides subsp. capri

Mycoplasma mycoides subsp. mycoides Large Colony (LC) type is a pathogen of goats causing contagious agalactia and respiratory disease, found on all continents where small ruminants are kept. It shares close genetic characteristics with M. mycoides subsp. capri. Substrate oxidation by 22 strains of M. mycoides subsp. mycoides LC from nine countries was compared with that of eight strains of M. mycoides subsp. capri from five countries. There was considerable similarity in the substrates used, but substrate saturation coefficients (Ks) varied for different substrates. Substrate utilization patterns and Ks values did not (1) significantly differentiate the LC strains from each other, (2) show any correlation with geographical origin, or (3) distinguish the LC strains from the capri strains. These results support previous studies justifying the reclassification of these subspecies as a single species

Status of the Onsala Twin Telescopes – Two Years After the Inauguration

We give a brief overview on the status of\ua0the Onsala twin telescopes (OTT), two years after their\ua0inauguration. The dierent components of the VGOS\ua0systems are briefly described, and the development towards\ua0routine operations

Status of the Onsala Twin Telescopes – One Year After the Inauguration

We briefly describe the status of the Onsala\ua0twin telescopes and the experience gained since the official\ua0inauguration in May 2017