1,146 research outputs found

    Leaf energy balance modelling as a tool to infer habitat preference in the early angiosperms

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    Despite more than a century of research, some key aspects of habitat preference and ecology of the earliest angiosperms remain poorly constrained. Proposed growth ecology has varied from opportunistic weedy species growing in full sun to slow-growing species limited to the shaded understorey of gymnosperm forests. Evidence suggests that the earliest angiosperms possessed low transpiration rates: gas exchange rates for extant basal angiosperms are low, as are the reconstructed gas exchange rates for the oldest known angiosperm leaf fossils. Leaves with low transpirational capacity are vulnerable to overheating in full sun, favouring the hypothesis that early angiosperms were limited to the shaded understorey. Here, modelled leaf temperatures are used to examine the thermal tolerance of some of the earliest angiosperms. Our results indicate that small leaf size could have mitigated the low transpirational cooling capacity of many early angiosperms, enabling many species to survive in full sun. We propose that during the earliest phases of the angiosperm leaf record, angiosperms may not have been limited to the understorey, and that some species were able to compete with ferns and gymnosperms in both shaded and sunny habitats, especially in the absence of competition from more rapidly growing and transpiring advanced lineages of angiosperms

    Character evolution and missing (morphological) data across Asteridae

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/1/ajb21050-sup-0007-AppendixS7.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/2/ajb21050_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/3/ajb21050-sup-0019-AppendixS19.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/4/ajb21050-sup-0013-AppendixS13.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/5/ajb21050-sup-0014-AppendixS14.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/6/ajb21050-sup-0012-AppendixS12.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/7/ajb21050-sup-0009-AppendixS9.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/8/ajb21050-sup-0018-AppendixS18.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/9/ajb21050.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/10/ajb21050-sup-0004-AppendixS4.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/11/ajb21050-sup-0008-AppendixS8.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/12/ajb21050-sup-0005-AppendixS5.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/13/ajb21050-sup-0017-AppendixS17.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/14/ajb21050-sup-0006-AppendixS6.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/15/ajb21050-sup-0011-AppendixS11.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/16/ajb21050-sup-0016-AppendixS16.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/17/ajb21050-sup-0015-AppendixS15.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/18/ajb21050-sup-0010-AppendixS10.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143691/19/ajb21050-sup-0003-AppendixS3.pd

    Monocot plastid phylogenomics, timeline, net rates of species diversification, the power of multiâ gene analyses, and a functional model for the origin of monocots

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/1/ajb21178-sup-0009-AppendixS9.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/2/ajb21178-sup-0020-AppendixS20.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/3/ajb21178.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/4/ajb21178-sup-0019-AppendixS19.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/5/ajb21178-sup-0010-AppendixS10.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/6/ajb21178-sup-0002-AppendixS2.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/7/ajb21178-sup-0006-AppendixS6.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/8/ajb21178-sup-0012-AppendixS12.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/9/ajb21178-sup-0017-AppendixS17.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/10/ajb21178-sup-0007-AppendixS7.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/11/ajb21178-sup-0001-AppendixS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/12/ajb21178-sup-0003-AppendixS3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/13/ajb21178-sup-0016-AppendixS16.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/14/ajb21178_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/15/ajb21178-sup-0008-AppendixS8.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/16/ajb21178-sup-0004-AppendixS4.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/17/ajb21178-sup-0018-AppendixS18.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/18/ajb21178-sup-0014-AppendixS14.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/19/ajb21178-sup-0011-AppendixS11.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/20/ajb21178-sup-0005-AppendixS5.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146610/21/ajb21178-sup-0015-AppendixS15.pd

    Current Radiation Issues for Programmable Elements and Devices

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    State of the an programmable devices are utilizing advanced processing technologies, non-standard circuit structures, and unique electrical elements in commercial-off-the-shelf (COTS)-based, high-performance devices. This paper will discuss that the above factors, coupled with the systems application environment, have a strong interplay that affect the radiation hardness of programmable devices and have resultant system impacts in (1) reliability of the unprogrammed, biased antifuse for heavy ions (rupture), (2) logic upset manifesting itself as clock upset, and (3) configuration upset. General radiation characteristics of advanced technologies are examined and manufacturers' modifications to their COTS-based and their impact on future programmable devices will be analyzed

    Foodways in transition: food plants, diet and local perceptions of change in a Costa Rican Ngäbe community

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    Background Indigenous populations are undergoing rapid ethnobiological, nutritional and socioeconomic transitions while being increasingly integrated into modernizing societies. To better understand the dynamics of these transitions, this article aims to characterize the cultural domain of food plants and analyze its relation with current day diets, and the local perceptions of changes given amongst the Ngäbe people of Southern Conte-Burica, Costa Rica, as production of food plants by its residents is hypothesized to be drastically in recession with an decreased local production in the area and new conservation and development paradigms being implemented. Methods Extensive freelisting, interviews and workshops were used to collect the data from 72 participants on their knowledge of food plants, their current dietary practices and their perceptions of change in local foodways, while cultural domain analysis, descriptive statistical analyses and development of fundamental explanatory themes were employed to analyze the data. Results Results show a food plants domain composed of 140 species, of which 85 % grow in the area, with a medium level of cultural consensus, and some age-based variation. Although many plants still grow in the area, in many key species a decrease on local production–even abandonment–was found, with much reduced cultivation areas. Yet, the domain appears to be largely theoretical, with little evidence of use; and the diet today is predominantly dependent on foods bought from the store (more than 50 % of basic ingredients), many of which were not salient or not even recognized as ‘food plants’ in freelists exercises. While changes in the importance of food plants were largely deemed a result of changes in cultural preferences for store bought processed food stuffs and changing values associated with farming and being food self-sufficient, Ngäbe were also aware of how changing household livelihood activities, and the subsequent loss of knowledge and use of food plants, were in fact being driven by changes in social and political policies, despite increases in forest cover and biodiversity. Conclusions Ngäbe foodways are changing in different and somewhat disconnected ways: knowledge of food plants is varied, reflecting most relevant changes in dietary practices such as lower cultivation areas and greater dependence on food from stores by all families. We attribute dietary shifts to socioeconomic and political changes in recent decades, in particular to a reduction of local production of food, new economic structures and agents related to the State and globalization

    Taxonomic surrogacy in biodiversity assessments, and the meaning of Linnaean ranks

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    Copyright © 2006 The Natural History MuseumThe majority of biodiversity assessments use species as the base unit. Recently, a series of studies have suggested replacing numbers of species with higher ranked taxa (genera, families, etc.); a method known as taxonomic surrogacy that has an important potential to save time and resources in assesments of biological diversity. We examine the relationships between taxa and ranks, and suggest that species/higher taxon exchanges are founded on misconceptions about the properties of Linnaean classification. Rank allocations in current classifications constitute a heterogeneous mixture of various historical and contemporary views. Even if all taxa were monophyletic, those referred to the same rank would simply denote separate clades without further equivalence. We conclude that they are no more comparable than any other, non-nested taxa, such as, for example, the genus Rattus and the phylum Arthropoda, and that taxonomic surrogacy lacks justification. These problems are also illustrated with data of polychaetous annelid worms from a broad-scale study of benthic biodiversity and species distributions in the Irish Sea. A recent consensus phylogeny for polychaetes is used to provide three different family-level classifications of polychaetes. We use families as a surrogate for species, and present Shannon–Wiener diversity indices for the different sites and the three different classifications, showing how the diversity measures rely on subjective rank allocations.Y. Bertrand, F. Pleijel and G. W. Rous

    Cytotoxic activity of proteins isolated from extracts of Corydalis cava tubers in human cervical carcinoma HeLa cells

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    <p>Abstract</p> <p>Background</p> <p><it>Corydalis cava </it>Schweigg. & Koerte, the plant of numerous pharmacological activities, together with the studied earlier by our group <it>Chelidonium majus </it>L. (Greater Celandine), belong to the family <it>Papaveraceae</it>. The plant grows in Central and South Europe and produces the sizeable subterraneous tubers, empty inside, which are extremely resistant to various pathogen attacks. The <it>Corydalis sp. </it>tubers are a rich source of many biologically active substances, with the extensive use in European and Asian folk medicine. They have analgetic, sedating, narcotic, anti-inflammatory, anti-allergic and anti-tumour activities. On the other hand, there is no information about possible biological activities of proteins contained in <it>Corydalis cava </it>tubers.</p> <p>Methods</p> <p>Nucleolytic proteins were isolated from the tubers of <it>C. cava </it>by separation on a heparin column and tested for DNase activity. Protein fractions showing nucleolytic activity were tested for cytotoxic activity in human cervical carcinoma HeLa cells. Cultures of HeLa cells were conducted in the presence of three protein concentrations: 42, 83 and 167 ng/ml during 48 h. Viability of cell cultures was appraised using XTT colorimetric test. Protein fractions were separated and protein bands were excised and sent for identification by mass spectrometry (LC-ESI-MS/MS).</p> <p>Results</p> <p>The studied protein fractions showed an inhibiting effect on mitochondrial activity of HeLa cells, depending on the administered dose of proteins. The most pronounced effect was obtained with the highest concentration of the protein (167 ng/ml) - 43.45 ± 3% mitochondrial activity of HeLa cells were inhibited. Mass spectrometry results for the proteins of applied fractions showed that they contained plant defense- and pathogenesis-related (PR) proteins.</p> <p>Conclusions</p> <p>The cytotoxic effect of studied proteins toward HeLa cell line cells has been evident and dependent on increasing dose of the protein. The present study, most probably, represents the first investigations on the effect of purified PR proteins from tuber extracts of a pharmacologically active plant on cell lines.</p
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