Search results for "ATR"
showing 10 items of 21758 documents
Is the impact of environmental noise visible in the dynamics of age-structured populations?
2001
Climate change has ignited lively research into its impact on various population–level processes. The research agenda in ecology says that some of the fluctuations in population size are accountable for by the external noise (e.g. weather) modulating the dynamics of populations. We obeyed the agenda by assuming population growth after a resource–limited Leslie matrix model in an age–structured population. The renewal process was disturbed by superimposing noise on the development of numbers in one or several age groups. We constructed models for iteroparous and semelparous breeders so that, for both categories, the population growth rate was matching. We analysed how the modulated populatio…
Variation in parasite resistance of Arctic charr, Salvelinus alpinus, between and within sympatric morphs
2021
Abstract Genetic variation in resistance against parasite infections is a predominant feature in host–parasite systems. However, mechanisms maintaining genetic polymorphism in resistance in natural host populations are generally poorly known. We explored whether differences in natural infection pressure between resource‐based morphs of Arctic charr (Salvelinus alpinus) have resulted in differentiation in resistance profiles. We experimentally exposed offspring of two morphs from Lake Þingvallavatn (Iceland), the pelagic planktivorous charr (“murta”) and the large benthivorous charr (“kuðungableikja”), to their common parasite, eye fluke Diplostomum baeri, infecting the eye humor. We found t…
Spectroscopic analysis of hot-water- and dilute-acid-extracted hardwood and softwood chips
2017
Hot-water and dilute sulfuric acid pretreatments were performed prior to chemical pulping for silver/white birch (Betula pendula/B. pubescens) and Scots pine (Pinus sylvestris) chips to determine if varying pretreatment conditions on the original wood material were detectable via attenuated total reflectance (ATR) infrared spectroscopy. Pretreatment conditions varied with respect to temperature (130 °C and 150 °C) and treatment time (from 30 min to 120 min). The effects of the pretreatments on the composition of wood chips were determined by ATR infrared spectroscopy. The spectral data were compared to those determined by common wood chemistry analyses to evaluate the suitability of ATR spe…
Role of host genetic diversity for susceptibility-to-infection in the evolution of virulence of a plant virus
2019
Predicting viral emergence is difficult due to the stochastic nature of the underlying processes and the many factors that govern pathogen evolution. Environmental factors affecting the host, the pathogen and the interaction between both are key in emergence. In particular, infectious disease dynamics are affected by spatiotemporal heterogeneity in their environments. A broad knowledge of these factors will allow better estimating where and when viral emergence is more likely to occur. Here, we investigate how the population structure for susceptibility-to-infection genes of the plant Arabidopsis thaliana shapes the evolution of Turnip mosaic virus (TuMV). For doing so we have evolved TuMV …
Bachelor groups form due to individual choices or environmental disrupters in African striped mice
2021
International audience; In several mammal species, bachelor groups occur as a regular life history stage between dispersal and becoming the breeding male of a multi-female group. However, it is rarely investigated how such groups come into existence and how males that choose this strategy differ in life history traits from other males. Males of the socially flexible African striped mouse Rhabdomys pumilio have been historically reported to adopt one of three alternative tactics, i.e., small group-living philopatric males, intermediate solitary living roaming males, or large group-living territorial males. Here, we describe for the first time, bachelors as a fourth male tactic. Using long-te…
“A cleaner break”: Genetic divergence between geographic groups and sympatric phenotypes revealed in ballan wrasse (Labrus bergylta)
2020
Abstract Capture and long‐distance translocation of cleaner fish to control lice infestations on marine salmonid farms has the potential to influence wild populations via overexploitation in source regions, and introgression in recipient regions. Knowledge of population genetic structure is therefore required. We studied the genetic structure of ballan wrasse, a phenotypically diverse and extensively used cleaner fish, from 18 locations in Norway and Sweden, and from Galicia, Spain, using 82 SNP markers. We detected two very distinct genetic groups in Scandinavia, northwestern and southeastern. These groups were split by a stretch of sandy beaches in southwest Norway, representing a habitat…
Soybean and casein hydrolysates induce grapevine immune responses and resistance against Plasmopara viticola
2014
International audience; Plasmopara viticola, the causal agent of grapevine downy mildew, is one of the most devastating grape pathogen in Europe and North America. Although phytochemicals are used to control pathogen infections, the appearance of resistant strains and the concern for possible adverse effects on environment and human health are increasing the search for alternative strategies. In the present investigation, we successfully tested two protein hydrolysates from soybean (soy) and casein (cas) to trigger grapevine resistance against P. viticola. On Vitis vinifera cv. Marselan plants, the application of soy and cas reduced the infected leaf surface by 76 and 63%, as compared to th…
A case study of the coconut crab Birgus latro on Zanzibar highlights global threats and conservation solutions
2021
Abstract The coconut crab Birgus latro, the largest terrestrial decapod, is under threat in most parts of its geographical range. Its life cycle involves two biomes (restricted terrestrial habitats near the coast, and salt water currents of the tropical Indian and Pacific Oceans). Its dependence on coastal habitat means it is highly vulnerable to the habitat destruction that typically accompanies human population expansion along coastlines. Additionally, it has a slow reproductive rate and can reach large adult body sizes that, together with its slow movement when on land, make it highly susceptible to overharvesting. We studied the distribution and population changes of coconut crabs at 15…
Press and bullfighting. The strength of the emotions
2018
Las corridas de toros fueron, tanto por el número asistentes como por la cantidad de festejos que se llevaron a cabo, el primer gran espectáculo de masas que se conoció en España. Enraizado en la fiesta popular, el espectáculo taurino será reconvertido en fiesta nacional a fines del siglo XIX, con el concurso de una prensa que crece en la misma medida que lo hace el sensacionalismo, y el interés de un Estado que utilizará las emociones de los toros para fomentar el amor a la patria. En este trabajo se aborda la dimensión cultural del festejo, su utilización política y el papel fundamental que juega la prensa. The bullfights were the first big spectacle of masses that was known in Spain, so …
Water temperature, not fish morph, determines parasite infections of sympatric Icelandic threespine sticklebacks (Gasterosteus aculeatus)
2013
Parasite communities of fishes are known to respond directly to the abiotic environment of the host, for example, to water quality and water temperature. Biotic factors are also important as they affect the exposure profile through heterogeneities in parasite distribution in the environment. Parasites in a particular environment may pose a strong selection on fish. For example, ecological differences in selection by parasites have been hypothesized to facilitate evolutionary differentiation of freshwater fish morphs specializing on different food types. However, as parasites may also respond directly to abiotic environment the parasite risk does not depend only on biotic features of the hos…