Search results for "sellu"
showing 10 items of 69 documents
Mechanical properties of natural fiber composites produced using dynamic sheet former
2018
Composites formed from wood fibers and man-made cellulosic fibers in PLA (polylactic acid) matrix, manufactured using sheet forming technique and hot pressing, are studied. The composites have very low density (due to high porosity) and rather good elastic modulus and tensile strength. As expected, these properties for the four types of wood fiber composites studied here improve with increasing weight fraction of fibers, even if porosity is also increasing. On the contrary, for man-made cellulosic fiber composites with circular fiber cross-section, the increasing fiber weight fraction (accompanied by increasing void content) has detrimental effect on stiffness and strength. The differences …
Lake browning impacts community structure and essential fatty acid content of littoral invertebrates in boreal lakes
2021
AbstractMany lakes in the northern hemisphere are browning due to increasing concentrations of terrestrial dissolved organic carbon (DOC). The consequences of lake browning to littoral invertebrates, however, are not fully understood. We analyzed community structure and fatty acid (FA) profiles of littoral invertebrates in humic (DOC-rich) and clear-water lakes in Eastern Finland. We found higher abundance of chironomids (Diptera: Chironomidae) in humic compared to clear-water lakes, whereas stoneflies (Plecoptera) and mayflies (Ephemeroptera: Baetidae) were more abundant in clear-water lakes. Taxon explained 65% of the differences in the FA composition of littoral invertebrates. However, t…
Täpläravun (Pacifastacus leniusculus) vaikutus särjen (Rutilus rutilus) loisiin Päijänteellä
2013
Täplärapu (Pacifastacus leniusculus) on Suomen vesistöissä verrattain uusi vieraslaji, joka leviää sekä suunnitelluin istutuksin että suunnittelematta uusille alueille. Täplärapu on alun perin tuotu Suomeen korvaamaan rapuruton turmelemia jokirapukantoja, mutta sitä on istutettu myös alueille, joissa ei alkuperäistä rapukantaa ole aiemmin ollut. Kotoperäiseen jokirapuun verrattuna täplärapu on paitsi vastustuskykyisempi rapurutolle, myös nopeampi kasvamaan ja lisääntymään. Täplärapu kasvaa jokirapua suuremmaksi ja on luonteeltaan aggressiivisempi. Vieraslajina täplärapu voi muuttaa uuden elinympäristön rakennetta ja toimintaa. Täplärapu käyttää ravintonaan muun muassa selkärangattomia pohja…
Seasonal changes in host phenotype manipulation by an acanthocephalan: time to be transmitted?
2009
Parasitology, 136 (2)
Zu den Ursachen der unterschiedlichen pH-Empfindlichkeit vonGammarus pulex L., G.fossarum KOCH (Amphipoda) undAselus aquaticus L. (Isopoda)
1992
By means of ion chromatography the extensive and significantly higher loss of ions of G. pulex and G. fossarum in acid water (pH 3.0) as compared to neutral water is proved. While cations are being accumulated in the water, some ions (Na+, Cl−) leave the hemolymph in important percentage, others increase highly after being set free from the cells (K+ and Ca2+). The loss of cations with Asellus aquaticus in acid water (pH 3) is clearly lower than with Gammarus, and it is not significantly higher than when the animals are put into neutral water.
Présence d’Asellides stygobies (Crustacea, Isopoda, Aselloidea) dans la région du Primorye, Sibérie sud-orientale
1993
Two species of anophthalmous, unpigmentedasellids have been found in springs and groundwaters of S.E. Siberia (Primorye region). Asellus (Asellus) primoryensis n. sp. is closelyrelated to the epigean species A. (A.) hilgendorfii Bovallius, 1886, as is the case for all stygobiont Asellus (Asellus) species previously known from the Japanese archipelago. Sibirasellus parpurae n. g., n. sp. is closely related to the microphthalmous species Asellus dentifer Birstein & Levanidov, 1952 from the Ussuri Basin (Khor region), now type-species of the new genus Sibirasellus. These two species show several original characters: body covered by numerous cuticular squamulae, mandibular palp reduced (gla…
Data from: Phylogenomics of Lophotrochozoa with consideration of systematic error
2021
Phylogenomic studies have improved understanding of deep metazoan phylogeny and show promise for resolving incongruences among analyses based on limited numbers of loci. One region of the animal tree that has been especially difficult to resolve, even with phylogenomic approaches, is relationships within Lophotrochozoa (the animal clade that includes molluscs, annelids, and flatworms among others). Lack of resolution in phylogenomic analyses could be due to insufficient phylogenetic signal, limitations in taxon and/or gene sampling, or systematic error. Here, we investigated why lophotrochozoan phylogeny has been such a difficult question to answer by identifying and reducing sources of sys…
Data from: Phylogenomics of Lophotrochozoa with consideration of systematic error
2016
Phylogenomic studies have improved understanding of deep metazoan phylogeny and show promise for resolving incongruences among analyses based on limited numbers of loci. One region of the animal tree that has been especially difficult to resolve, even with phylogenomic approaches, is relationships within Lophotrochozoa (the animal clade that includes molluscs, annelids, and flatworms among others). Lack of resolution in phylogenomic analyses could be due to insufficient phylogenetic signal, limitations in taxon and/or gene sampling, or systematic error. Here, we investigated why lophotrochozoan phylogeny has been such a difficult question to answer by identifying and reducing sources of sys…
Kontrastin lisääminen puukuidun rakenteen selvittämiseksi ja paikallistamiseksi paperiarkista röntgentomografialla
2011
Pro gradu -tutkielman kirjallisuusosassa tavoitteena oli esitellä kemiallisia kontrastin lisäysmenetelmiä puukuitumateriaalille. Kontrastin lisäyksen tavoitteena on pystyä paikallistamaan kuitufraktioita, kuten nanoselluloosaa ja hienoainesta, paperiarkista röntgentomografiakuvauksen avulla. Kuidun eri kerrosten kontrastien lisääminen toisiin kerroksiin nähden auttaisi myös kuidun yksityiskohtaisen kerrosrakenteen määrittämisessä tomografiakuvantamisella, mikä on myös yhtenä tavoiteltavana kohteena. Alussa aihetta pohjustetaan kertomalla tomografiasta materiaalin rakenteen tutkimusmenetelmänä ja syvennytään ymmärtämään kuidun monimutkaista rakennetta. Merkintä- ja värjäysmenetelmiä käydään …
Sexual selection, antennae length and the mating advantage of large males in Asellus aquaticus
2003
In crustacean species with precopulatory mate-guarding, sexual size dimorphism has most often been regarded as the consequence of a large male advantage in contest competition for access to females. However, large body size in males may also be favoured indirectly through scramble competition. This might partly be the case if the actual target of selection is a morphological character, closely correlated with body size, involved in the detection of receptive females. We studied sexual selection on body size and antennae length in natural populations of Asellus aquaticus, an isopod species with precopulatory mate guarding. In this species, males are larger than females and male pairing succe…