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Wyszukujesz frazę "Mitchell, A." wg kryterium: Autor


Tytuł:
Optical Correlation Using Four Wave Mixing in a Highly Nonlinear Fibre for Real-Time Serialized Ultrafast Systems
Autorzy:
Shalihah, F.
Mitchell, A.
Bui, L.
Tematy:
broadband
Dispersive Fourier Transform
four wave mixing
nonlinearity
optical correlation
Optical Signal Processing
Real-Time Ultrafast Systems
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/226196.pdf  Link otwiera się w nowym oknie
Opis:
A method of all-optical correlation is proposed using the nonlinear phenomena Four Wave Mixing (FWM) of two different signals. The method shows a serial solution where correlation of an ultrafast real-time serialized broadband source is demonstrated using a Highly Non-Linear Fibre (HNLF) with correlation rate reaching 200MHz.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Testate amoebae (protists) as palaeoenvironmental indicators in peatlands
Autorzy:
Lamentowicz, M.
Mitchell, E. A. D.
Tematy:
torfowiska mszarne (Sphagnum)
ameby skorupkowe
Protozoa
funkcja transferu
analiza pyłkowa
holocen
paleoekologia
hydrologia
klimat
Bory Tucholskie
Sphagnum-dominated peatlands
Testate amoebae
protozoa
transfer function
pollen analysis
Holocene
palaeoecology
hydrology
climate
Tuchola Pinewoods
Pokaż więcej
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:
https://bibliotekanauki.pl/articles/1186084.pdf  Link otwiera się w nowym oknie
Opis:
Ameby skorupkowe (Testacea) to jednokomórkowe organizmy, które żyją w środowiskach słodkowodnych, w większości siedlisk lądowych (glebie, mszakach, jeziorach, rzekach) oraz w siedliskach słonawych (np. w ujściowych partiach rzek). Testacea występują licznie w mchach torfowcach (Sphagnum), gdzie zasiedlają ich górną część oraz natleniony stropowy fragment torfu. Skorupki ameb dobrze zachowują sie w torfie oraz w mniejszym stopniu w osadach jeziornych. Główny wysiłek powinien być skoncentrowany na budowaniu regionalnych funkcji transferu (transfer function; matematyczny obraz relacji organizmu w stosunku do środowiska -obecność poszczególnych taksonów w materiale kopalnym jest funkcją przeszłych parametrów środowiskowych). Dla kilku obszarów już one powstały, ale brak tego rodzaju danych dla centralnej części Europy. Polskie dane są wyjątkowo istotne, ponieważ obszar ten znajduje się pod wpływem różnych wpływów klimatycznych - od klimatu oceanicznego do kontynentalnego. Porównanie naszych danych z informacjami z innych stanowisk w Europie i na świecie może wykazać, w jak odmienny sposób reagują polskie torfowiska na zmiany klimatyczne. Artykuł ma trzy cele: (a) zaprezentowanie potrzeby badań ekologii ameb skorupkowych w Europie centralnej, (b) przedstawienie potencjału rekonstrukcji paleośrodowisk na bazie wielu wskaźników, gdzie ameby skorupkowe stanowią integralną część metod badań paleoekologii i (c) zaprezentowanie naszych badań nad Testacea w Polsce w szerszej, globalnej perspektywie.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Certesella larai (Amoebozoa: Arcellinida: Hyalospheniformes) a new soil testate amoeba species from the Dominican Republic and Chile challenges the definition of genera Certesella and Porosia
Autorzy:
Bobrov, Anatoly
Duckert, Clément
Mitchell, Edward A. D.
Tematy:
Testate amoebae
Hyalospheniidae
genus Porosia
genus Certesella
forest litter
peat bog
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Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Powiązania:
https://bibliotekanauki.pl/articles/2041966.pdf  Link otwiera się w nowym oknie
Opis:
Microbial diversity is known to be huge but remains only partly documented. Testate amoebae are a relatively well studied group or free-living protists that build morphologically characteristic shells on which the taxonomy of this group is mainly based. Among testate amoebae, the Hyalospheniformes are especially well documented and are a model group for microbial biogeography. Here we describe a new species of genus Certesella from Sphagnum mosses and forest litter samples collected in the Dominican Republic and Chile. We name this species Certesella larai to honour our esteemed colleague Enrique Lara. This species bears two large pores connected by tube, which are characteristic of the genera Porosia and Certesella. The new species fits best in the latter genus given the presence of a distinct, sometimes denticulated, neck with a bulge that is absent in genus Porosia but occurs in Certesella. Its elongated shape (length/breadth ratio 2.03–2.58) only overlaps with C. certesi, which is distinguishable by the presence of a distinct longitudinal groove in the neck region that is absent from the new species. Interestingly most specimens lacked the internal teeth which are usually present in members of genus Certesella. As such, while the morphology of C. larai strongly suggests a belonging to genus Certesella, molecular analyses are still required to confirm its phylogenetic position, clarify the relationships among all species in genera Porosia and Certesella and the definition and validity of these two genera. The presence of this new species in two rather distant regions – Caribbean and central Chile – suggests it is likely widespread, but possibly rare. However, this perception may be due to a sampling bias in favour of Sphagnum mosses and wet and organic-rich habitats. This illustrates the need for a more systematic sampling effort to document the full and mostly unknown taxonomic diversity of soil protists.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Historia rozwoju dwóch torfowisk mszarnych w Borach Tucholskich
Developmental history of two kettle-hole mires in Tuchola Pinewoods (N Poland)
Autorzy:
Lamentowicz, M.
Obremska, M.
Mitchell, Edward A.D.
Tematy:
torfowisko
analiza palinologiczna
analiza ameb skorupkowych
analiza makroszczątków roślinnych
kettle-hole mire
Sphagnum mire
Testate amoebae
pollen
plant macrofossils
palaeohydrology
terrestrialization
weighted averaging
quantitative reconstruction
Pokaż więcej
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:
https://bibliotekanauki.pl/articles/2074410.pdf  Link otwiera się w nowym oknie
Opis:
Our research confirmed the value of kettle-hole mires for reconstructing Holocene environmental changes. The multi-proxy approach in which three palaeoecological methods were used (analyses of testate amoebae, plant macrofossils and pollen) improved the interpretation potential. We studied two Sphagnum mires situated in Tuchola Pinewoods (N Poland). In Tuchola mire 9000 years of environmental changes (groundwater level and pH) were recorded. Water table changes inferred from Tuchola mire show patterns similar to regional hydrological changes recorded in Polish lakes and mires as well as in other European sites. Jelenia Wyspa mire recorded changes in local vegetation and palaeohydrology during the last 1500 years. A rise in the groundwater table, caused by deforestation in the catchment area, allowed Sphagnum to expand. Consequently, the peatland evolved into an oligotrophic mire dominated by peat mosses. Approx. 200 years ago water pH increased and subsequently decreased, the lowest value being associated with the deforestation maximum. Furthermore, the planting of pine probably also caused an acidification of Jelenia Wyspa mire.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Response of Sphagnum Testate Amoebae to Drainage, Subsequent Re-wetting and Associated Changes in the Moss Carpet – Results from a Three Year Mesocosm Experiment
Autorzy:
Koenig, Isabelle
Schwendener, Florence
Mulot, Matthieu
Mitchell, Edward A. D.
Tematy:
Mesocosm experiment
Testate amoebae
Functional traits
Recovery
Disturbance
Sphagnum peatlands
bio-indicators
water table depth
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Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Powiązania:
https://bibliotekanauki.pl/articles/52397249.pdf  Link otwiera się w nowym oknie
Opis:
Sphagnum peatlands represent a globally significant pool and sink of carbon but these functions are threatened by ongoing climate change. Testate amoebae are useful bioindicators of hydrological changes, but little experimental work has been done on the impact of water table changes on communities. Using a mesocosm experimental setting that was previously used to assess the impact of drought disturbance on communities and ecosystem processes with three contrasted water table positions: wet (–4 cm), intermediate (–15 cm) and dry (–25 cm), we studied the capacity of testate amoeba communities to recover when the water table was kept at –10 cm for all plots. The overall experiment lasted three years. We assessed the taxonomic and functional trait responses of testate amoeba communities. The selected traits were hypothesised to be correlated to moisture content (response traits: shell size, aperture position) or trophic role (effect traits: mixotrophy, aperture size controlling prey range). During the disturbance phase, the mixotrophic species Hyalosphenia papilio dominated the wet and intermediate plots, while the community shifted to a dominance of “dry indicators” (Corythion dubium, Nebela tincta, Cryptodifflugia oviformis) and corresponding traits (loss of mixotrophy, and dominance of smaller taxa with ventral or ventral-central aperture) in dry plots. During the recovery phase we observed two contrasted trends in the previously wet and intermediate plots: communities remained similar where the Sphagnum carpet remained intact but species and traits indicators of drier conditions increased in plots where it had degraded. In the former dry plots, indicators and traits of wet conditions increased by the end of the experiment. This is one of the first experiment simulating a disturbance and subsequent recovery in ex-situ mesocosms of Sphagnum peatland focusing on the response of testate amoebae community structure as well as functional traits to water table manipulation. The results generally confirmed that testate amoebae respond within a few months to hydrological changes and thus represent useful bioindicators for assessing current and past hydrological changes in Sphagnum peatlands.  
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyalosphenia papilio paynei subsp. nov. – a highly conspicuous and localized Sphagnum peatland testate amoeba
Autorzy:
Duckert, Clément
Greeves, Evelyn
Blandenier, Quentin
Payne, Richard J.
Mitchell, Edward A.D.
Tematy:
Testate amoebae
taxonomy
Hyalosphenia
dispersal limitations
microbial biogeography
Pokaż więcej
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Powiązania:
https://bibliotekanauki.pl/articles/51995619.pdf  Link otwiera się w nowym oknie
Opis:
Most eukaryotic microbial biodiversity is undescribed, and most species might be morphologically indistinguishable. Notable exceptions are so-called flagship species which are highly conspicuous and can therefore be used to address biogeographical questions. Here we describe Hyalosphenia papilio subsp. paynei, an arcellinid testate amoeba (Amoebozoa; Arcellinida; Hyalospheniidae) from wet hollows in two Sphagnum peatlands, one in Wales and one in Ireland. Phylogenetic analysis based on Cytochrome Coxidase subunit I (COI) sequencing places it within the lineage A of the H. papilio complex, but it differs from all 13 known H. papilio genetic lineages by its very distinctive, wider than long, morphology. The fact that such a conspicuous taxon was never reported in hundreds of studies published on Holarctic Sphagnum peatlands since Leidy’s description of H. papilio in 1874 suggests that this subspecies has not dispersed and survived beyond Britain and Ireland. Furthermore its genetic similarity to H. papilio s. str. suggests that it has recently evolved. The discovery of this new taxon calls for a more detailed analysis of the morphological, ecological and molecular diversity of the H. papilio species complex.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Canine respiratory coronavirus, bovine coronavirus, and human coronavirus OC43 : receptors and attachment factors
Autorzy:
Ochman, Marek
Rajfur, Zenon
Owczarek, Katarzyna
Szczepański, Artur
Maksym, Beata
Bzowska, Monika
Pyrć, Krzysztof
Drebot, Inga
Guła, Katarzyna
Mitchell, Judy A.
Opis:
Despite high similarity of canine respiratory coronavirus (CRCoV), bovine coronavirus, (BCoV) and human coronavirus OC43 (HCoV-OC43), these viruses differ in species specificity. For years it was believed that they share receptor specificity, utilizing sialic acids for cell surface attachment, internalization, and entry. Interestingly, careful literature analysis shows that viruses indeed bind to the cell surface via sialic acids, but there is no solid data that these moieties mediate virus entry. In our study, using a number of techniques, we showed that all three viruses are indeed able to bind to sialic acids to a different extent, but these molecules render the cells permissive only for the clinical strain of HCoV-OC43, while for others they serve only as attachment receptors. CRCoV and BCoV appear to employ human leukocyte antigen class I (HLA-1) as the entry receptor. Furthermore, we identified heparan sulfate as an alternative attachment factor, but this may be related to the cell culture adaptation, as in ex vivo conditions, it does not seem to play a significant role. Summarizing, we delineated early events during CRCoV, BCoV, and HCoV-OC43 entry and systematically studied the attachment and entry receptor utilized by these viruses.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł

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