Search results for "Tove"

Species interactions, environmental gradients and body size shape population niche width

2021

1. Competition for shared resources is commonly assumed to restrict population-level niche width of coexisting species. However, the identity and abundance of coexisting species, the prevailing environmental conditions, and the individual body size may shape the effects of interspecific interactions on species’ niche width. 2. Here we study the effects of interspecific and intraspecific interactions, lake area and altitude, and fish body size on the trophic niche width and resource use of a generalist predator, the littoral-dwelling large, sparsely rakered morph of European whitefish (Coregonus lavaretus; hereafter LSR whitefish). We use stable isotope, diet and survey fishing data from 14 …

Whole-Lake Sugar Addition Demonstrates Trophic Transfer of Dissolved Organic Carbon to Top Consumers

2017

Terrestrial dissolved organic carbon (DOC) provides an external carbon source to lake ecosystems. However, there is ongoing debate about whether external DOC that enters a lake can pass up the food web to support top consumers. We show, from experimental manipulation of a whole lake, that externally loaded DOC can contribute appreciably to fish biomass. Monthly additions of cane sugar with a distinct carbon stable isotope value during 2 years rapidly enriched the 13C content of zooplankton and macroinvertebrates, with a more gradual 13C enrichment of fish. After sugar addition stopped, the 13C content of consumers reverted towards original values. A simple isotope mixing model indicated tha…

II) Wood pellets for home heating can be considered environmentally friendly fuels? Heavy metals determination by inductively coupled plasma-optical …

2016

Abstract The aim of the present study was to determine the concentrations of twelve potentially hazardous elements in wood pellet ashes obtained by the combustion of 13 pellet brands for sale in Italy, the impact of adding the ashes to soils and health risk of operator due to dust exposure. Samples were analysed by Inductively Coupled Plasma Optical Emission Spectrometry. The concentrations of heavy metals in ashes from stoves ranged from 0.41 to 7.2 mg kg − 1 for As, from 1.3 to 12 mg kg − 1 for Sb, from 1.8 to 12 mg kg − 1 for Zn, from 0.23 to 0.8 mg kg − 1 for Pb, from 0.18 to 2.8 mg kg − 1 for Ni, from 0.09 to 1.0 mg kg − 1 for Cd, from 0.46 to 3.4 mg kg − 1 for Cr, from 0.94 to 2.7 mg …

Wood pellets for home heating can be considered environmentally friendly fuels? Polycyclic aromatic hydrocarbons (PAHs) in their ashes

2016

This paper reports the results of the first quantitative investigations of PAHs in wood pellet ashes. Investigations were carried out into the fifteen PAHs identified by the US-Environment Protection Agency (US-EPA) as requiring priority monitoring; other non-US-EPA listed PAHs and perylene were also investigated. The total concentrations for the 17 investigated compounds, expressed as the sum of the concentrations (∑PAHs), in the ashes produced by the wood pellet combustion, ranged from 0.064mg kg-1 to 0.90mg kg-1 of dry weight with a means of 0.31mg kg-1. The lowest concentrations (<0.1mg kg-1) were measured in the conifer ash samples. Concentrations of PAHs found in this paper will al…

Trematode cercariae as prey for zooplankton: effect on fitness traits of predators.

2019

AbstractRemoval of parasite free-living stages by predators has previously been suggested an important factor controlling parasite transmission in aquatic habitats. Experimental studies of zooplankton predation on macroparasite larvae are, however, scarce. We tested whether trematode cercariae, which are often numerous in shallow waters, are suitable prey for syntopic zooplankters. Feeding rates and survival of freshwater cyclopoids (Megacyclops viridis, Macrocyclops distinctus), calanoids (Arctodiaptomus paulseni), cladocerans (Sida crystallina) and rotifers Asplanchna spp., fed with cercariae of Diplostomum pseudospathaceum, a common fish trematode, were studied. In additional long-term e…

Eväitä elämään : kolmas- ja neljäsluokkalaisten oppilaiden käsityksiä itsetuntoon yhteydessä olevista tekijöistä koulussa

2000

Assessing the influence of confounding biological factors when estimating bioaccumulation of PCBs with passive samplers in aquatic ecosystems

2017

Passive samplers are promising surrogates for organisms, mimicking bioaccumulation. However, several biological characteristics disturb the passive partitioning process in organisms by accelerating or restraining bioaccumulation, resulting in species-specific body residues of hydrophobic organic contaminants (HOCs). In addition to site-specific characteristics and HOC concentrations, age, sex, diet, biotransformation capability and habitat-specific characteristics may affect body residues. Two passive sampler types, polyethylene (PE) and polydimethylsiloxane (PDMS) were deployed in a PCB-contaminated freshwater lake water and sediment, respectively, to assess their bioaccumulation predictio…

Kilpailu vaikuttaa nieriän ravintoon

2013

Lapin nieriäkannat ovat monin paikoin taantuneet uusien kalalajien levittäytymisen seurauksena. Tuore väitöskirjatutkimus osoittaa, että nieriä voi vaihtaa ravintoaan ja elinpaikkaansa vähentääkseen kilpailua muiden kalalajien kanssa. nonPeerReviewed

Artificial Intelligence for Cybersecurity: A Systematic Mapping of Literature

2020

Due to the ever-increasing complexities in cybercrimes, there is the need for cybersecurity methods to be more robust and intelligent. This will make defense mechanisms to be capable of making real-time decisions that can effectively respond to sophisticated attacks. To support this, both researchers and practitioners need to be familiar with current methods of ensuring cybersecurity (CyberSec). In particular, the use of artificial intelligence for combating cybercrimes. However, there is lack of summaries on artificial intelligent methods for combating cybercrimes. To address this knowledge gap, this study sampled 131 articles from two main scholarly databases (ACM digital library and IEEE…

Autoveikala darbība Ziemeļkurzemes reģionā. Laika, telpas un sociālo, ekonomisko procesu izpēte

2016

Bakalaura darbs “Autoveikala darbība Ziemeļkurzemes reģionā. Laika, telpas sociālo un ekonomisko procesu izpēte” ir pētījums par veikalu uz riteņiem, kurš trīsdesmit gadus piegādā lauku iedzīvotājiem pārtiku, pievedot to pie mājām vai ciema centros. Autoveikalam ir izdevies ekonomiski mainīgajos apstākļos izdzīvot un turpināt savu darbību. Šī pakalojuma rezultātā ir vērojami vietējo dzīves apstākļi Latvijas laukos, sabiedriskās dzīves organizēšana, un tā ekonomiskā racionalitāte kā tirdzniecības punktam. Pētījuma mērķis- noskaidrot kā autoveikala darbība atspoguļo tā klientu iespējas un ikdienas norises laukos, Ziemeļkurzemes reģionā. Pētījuma rezultāti liecina, ka autoveikala klientūra ir …