Literatura académica sobre el tema "Common Lichens"
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Artículos de revistas sobre el tema "Common Lichens"
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Gordon, Catriona A., Rafael Herrera y Tom C. Hutchinson. "The use of a common epiphytic lichen as a bioindicator of atmospheric inputs to two Venezuelan cloud forests". Journal of Tropical Ecology 11, n.º 1 (febrero de 1995): 1–26. http://dx.doi.org/10.1017/s026646740000835x.
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ABSTRACTThe chemistry of epiphytic lichens was determined in two Venezuelan cloud forests adjacent to the Caracas Valley at Altos de Pipe and El Avila National Park. This is the second component of a two-part study examining the chemistry of fogs and their effects on sensitive biota in these forests. The widespread lichen Parmotrema madagascariaceum was chosen as an indicator of trace metal input. Background lichen collections and transplant experiments were carried out to evaluate spatial trends in atmospheric depositon of trace metals at different altitudes and exposures of the two montane locations. Elevated concentratons of metals including Pb and Zn were seen in lichen tissue and associated bark. Lead levels in lichens reached 190 μg g-1 dry wt. Lichens transplanted from relatively ‘clean’ to more polluted sites showed significant increases of metals, particularly Pb. Increases of up to 6.3 μg Pb g-1 mo-1 after 6 and 10 months were recorded relative to background and in situ lichen material. In contrast, when lichsens were reciprocally transplanted in nylon net bags from less to more exposed sites there was a significant decrease in Pb and Zn concentrations after 6 and 10 months. With long-term exposure to elevated concentrations of these trace metals epiphytic lichens, as well as other sensitive cloud forest biota, may be at risk of decline.
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Crête, Michel, Claude Morneau y René Nault. "Biomasse et espèces de lichens terrestres disponibles pour le caribou dans le nord du Québec". Canadian Journal of Botany 68, n.º 10 (1 de octubre de 1990): 2047–53. http://dx.doi.org/10.1139/b90-268.
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Following a two-stage sampling plan, 44 1-km2 primary units were systematically allocated between 53 and 59 ° latitude throughout northern Québec to estimate the biomass of terrestrial lichens. Lichens were collected in two secondary units (0.25 m2) located in parts of each primary unit where lichens were visible from a helicopter (lichen stratum). Overall, the lichen stratum covered 51% of the study area and lichen biomass averaged 1223 kg/ha (dry weight; SE = 201; n = 44). Almost 85% of the variance of this mean was attributable to variability between primary units. The biomass in the west was greater than in the east; it was the highest in the [Formula: see text]700-mm precipitation zone and the lowest in the 500- to 599-mm zone. Data on percent plant cover indicated mat mosses increased in importance over lichens in the east. There was a clear relationship between lichen biomass in secondary units on one hand and mat thickness and percent lichen ground cover on the other. Cladinia stellaris (Opiz) Brodo was the most common species; Alectoria ochroleuca (Hoffm.) Mass. and Cornicularia divergens Ach. were typical of the north, whereas Cladina mitis (Sandst.) Hustich characterized the south of the study area. The annual consumption of lichens by caribou was probably 0.5-0.9% of the available biomass in 1987. Key words: biomass, caribou, Cladina, lichens, Quebec.
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Paukov, Alexander, Anzhelika Teptina, Maria Morozova, Ekaterina Kruglova, Sergio E. Favero-Longo, Cora Bishop y Nishanta Rajakaruna. "The Effects of Edaphic and Climatic Factors on Secondary Lichen Chemistry: A Case Study Using Saxicolous Lichens". Diversity 11, n.º 6 (17 de junio de 2019): 94. http://dx.doi.org/10.3390/d11060094.
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Diversity of secondary lichen metabolites and their relationship to substrate and environmental parameters were studied in saxicolous lichens in the Middle and South Urals of Russia. Atranorin, usnic acid, gyrophoric acid, zeorin, norstictic acid, antraquinones and stictic acid were found in 73, 42, 41, 37, 36, 35 and 32 species, respectively, of 543 taxa collected. One hundred and ninety six species (i.e., 36% of total species documented) contained no secondary metabolites. Spectra of secondary metabolites of crustose lichens varied on different rock types, while in fruticose and foliose groups only those species without lichen acids were dependent on the substrate type. In Canonical Correspondence Analysis, secondary lichen metabolites were subdivided into groups depending on the concentration of Ca and metals in the substrate. Gyrophoric, lobaric, psoromic, rhizocarpic and stictic acids were common in crustose lichens in metal-poor habitats; species with antraquinones and lichens without any secondary metabolites were most abundant on limestone (alkalic and metal-poor), while other common lichen metabolites had no to minimal dependence on the chemistry of the substrate. The two additional abiotic factors affecting the composition of secondary metabolites were the maximum temperature of the warmest month and elevation. Our results suggest a range of possible relationships exist among lichen acids, rocks and climatic parameters. Furthermore, the same metabolite may affect both accumulation of metals and stress tolerance under unfavorable conditions.
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Greenfield, L. G. "Decomposition studies on New Zealand and antarctic lichens". Lichenologist 25, n.º 1 (enero de 1993): 73–82. http://dx.doi.org/10.1006/lich.1993.1014.
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AbstractThe decomposition of ground, dead (oven-dried) lichens has been studied in laboratory experiments that aimed to simulate decomposition in nature. Enzymes, common in soil animal guts and soil microbes, solubilized 29% of the lichen weight and 25% of lichen nitrogen. Approximately 9% of lichen nitrogen was mobilized to mineral forms during 97 days' incubation in soil or sand. Low moisture levels reduced the amount of nitrogen mobilized. In short-term (30 days) incubation studies, lichens at optimum moisture but low temperature lost 9% of their initial dry weight due to microbial metabolism. In contrast, lichens incubated for 30 and 135 days at similar moisture levels but higher temperatures lost 19% and 30% respectively of their initial dry weight due to microbial metabolism.
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Jaakkola, Lotta Maaria, Timo Päiviö Helle, Jussi Soppela, Markku Tapio Kuitunen y Mikko Juhani Yrjönen. "Effects of forest characteristics on the abundance of alectorioid lichens in northern Finland". Canadian Journal of Forest Research 36, n.º 11 (1 de noviembre de 2006): 2955–65. http://dx.doi.org/10.1139/x06-178.
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Quantitative knowledge of the abundance of epiphytic alectorioid lichens (Bryoria spp., Alectoria spp., and Usnea spp.) is important when evaluating the carrying capacity of the winter pastures of semidomesticated reindeer (Rangifer tarandus tarandus (L., 1758)) and woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)). This study, including a total of 234 sample plots, presents data on the biomass of alectorioid lichens in mature forests for the most common forest site types in the national parks of Oulanka, Pallas-Ounastunturi, and Lemmenjoki in northern Finland and relates them to forest stand characteristics. The biomass of alectorioid lichens on trees was estimated using the clump method in which the existing clumps of lichen thalli on branches are compared with clumps of lichens of known dry mass. Estimated biomasses were corrected by equations describing the ratio of estimated to measured biomass. We found the highest mean lichen biomasses (120 kg·ha–1) in subdry, Scotch pine (Pinus sylvestris L.) dominated sites above the timberline of Norway spruce (Picea abies (L.) Karst.). Below that timberline, the highest lichen biomasses were found in fresh (productive) sites dominated by Norway spruce. There the site-specific differences were mainly associated with tree species composition. Though in many previous studies forest age has been an important indicator of total lichen biomass, in our study areas lichen abundance was most commonly correlated with total volume of forest stands. The correlation of biomass with forest volume suggests that substrate availability was the most important limiting factor for alectorioid lichens in our study area. However, it is premature to say whether that is a common feature in northern forests over larger geographic areas.
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WA, Elkhateeb. "Lichentherapy: Highlights on the Pharmaceutical Potentials of Lichens". Open Access Journal of Microbiology & Biotechnology 6, n.º 2 (2021): 1–10. http://dx.doi.org/10.23880/oajmb-16000190.
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Lichens exist in every continent and have a history of being used as food, medicine, a source of dyes and animal feed. Lichens are now being used as natural indicators of climate change and for air quality monitoring worldwide. Lichens play an important role in many ecosystems and exist as a symbiotic association between fungi and algae or cyanobacteria. This symbiosis results in the production of unique secondary metabolites known as lichen substances, which arise within the thalli and are typically in crystal form on the surface of the fungal hyphae. Recently, lichens and their secondary metabolites have been receiving increased attention due to their nutritional value and pharmaceutical potential. This review aims to highlight on the importance and variety of common lichen substances (secondary metabolites). Finally, the commercialization of lichens is growing but, in the future, metabolic and biotechnological approaches can be used as an alternative product to overcome the limited availability of biologically active, commercially valuable and medicinally important secondary metabolite components.
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Ivanov, Dobri, Galina Yaneva, Irina Potoroko y Diana G. Ivanova. "Contribution of Cyanotoxins to the Ecotoxicological Role of Lichens". Toxins 13, n.º 5 (29 de abril de 2021): 321. http://dx.doi.org/10.3390/toxins13050321.
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The fascinating world of lichens draws the attention of the researchers because of the numerous properties of lichens used traditionally and, in modern times, as a raw material for medicines and in the perfumery industry, for food and spices, for fodder, as dyes, and for other various purposes all over the world. However, lichens being widespread symbiotic entities between fungi and photosynthetic partners may acquire toxic features due to either the fungi, algae, or cyano-procaryotes producing toxins. By this way, several common lichens acquire toxic features. In this survey, recent data about the ecology, phytogenetics, and biology of some lichens with respect to the associated toxin-producing cyanoprokaryotes in different habitats around the world are discussed. Special attention is paid to the common toxins, called microcystin and nodularin, produced mainly by the Nostoc species. The effective application of a series of modern research methods to approach the issue of lichen toxicity as contributed by the cyanophotobiont partner is emphasized.
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Ongaro, Silvia, Guglielmo Lione y Deborah Isocrono. "Composition and Conservation Value of Epiphytic Lichen Communities on Common Ash in North-Western Alps: A First Assessment". Forests 13, n.º 8 (14 de agosto de 2022): 1288. http://dx.doi.org/10.3390/f13081288.
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In the western sector of the Alps, and particularly in the Aosta Valley, lichenological communities on broad-leaved trees have received very little attention, and information about lichen species associated with common ash (Fraxinus excelsior L.) are still scanty. Therefore, in this study, we analyzed epiphytic lichen communities of ash trees to estimate their composition, their conservation value, and their association with some key environmental variables. Our results show that lichen communities appear to be different in terms of occurrence and frequencies in different sampling sites. The tested environmental variables contribute to shape the lichen communities, which are significantly different (p < 0.05) in sites characterized by different elevation, solar radiation, and source vicinity. The conservation value of lichen species was assessed by comparing distributional data at the national and local level. Our findings show that, in the Italian Alps, ash trees represent an important substrate for locally, or even nationally, rare lichens: 14 recorded species were not previously known in the study area, and some (Lecanora impudens and Rinodina polyspora) were included in the red list of Italian epiphytic lichens.
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Newmaster, Steven G., F. Wayne Bell y Dale H. Vitt. "The effects of glyphosate and triclopyr on common bryophytes and lichens in northwestern Ontario". Canadian Journal of Forest Research 29, n.º 7 (1 de agosto de 1999): 1101–11. http://dx.doi.org/10.1139/x99-083.
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The effects of two silvicultural herbicides (Vision®, Release®) on bryophytes and lichens were studied in a harvested boreal mixedwood ecosystem. A completely randomized design with 115 plots of 1 m2 allowed direct comparison between herbicides and their effects on community dynamics. Regression models were used to analyze the relationship between herbicide application rates (0.71-6.72 kg active ingredient/ha) and changes in bryophyte and lichen abundance and species richness for 2 years following herbicide application. Results showed that bryophyte and lichen abundance and species richness decreased after herbicide treatments. In general, herbicide applications reduced the diversity of forest mesophytes and weedy colonizers to an ecosystem with only a few species of colonizers. A combination of clustering techniques and ANOVA were used to divide bryophytes and lichens into three ecologically defined response groups: herbicide-tolerant colonizers, semi tolerant long-term stayers from dry open forest, and sensitive forest mesophytes.
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Matwiejuk, Anna. "Lichens of fruit trees in the selected locations in Podlaskie Voivodeship [North-Eastern Poland]". Ochrona Srodowiska i Zasobów Naturalnych 28, n.º 4 (1 de diciembre de 2017): 5–9. http://dx.doi.org/10.1515/oszn-2017-0023.
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Abstract The aim of this paper is to present the diversity of the lichen species on fruit trees (Malus sp., Pyrus sp., Prunus sp. and Cerasus sp.) growing in orchards in selected villages and towns in the Podlaskie Voivodeship. Fifty-six species of lichens were found. These were dominated by common lichens found on the bark of trees growing in built-up areas with prevailing heliophilous and nitrophilous species of the genera Physcia and Phaeophyscia. A richer lichen biota is characteristic of apple trees (52 species) and pear trees (36). Lichens of the apple trees constitute 78% of the biota of this phorophyte growing in the fruit orchards in Poland. Of the recorded species, only two (Ramalina farinacea, Usnea hirta) are covered by partial protection in Poland.
Tesis sobre el tema "Common Lichens"
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Leavitt, Steven. "Assessing Traditional Morphology- and Chemistry-Based Species Circumspections in Lichenized Ascomycetes: Character Evolution and Molecular Species Delimitation in Common Western North American Lichens". BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2191.
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Accurate species delimitation has critical implications for ecological and conservation studies; and for understanding factors driving diversification. However, a growing body of evidence indicates that morphology-based species circumspection in lichenized ascomycetes often fails to accurately represent the number of fungal species. The use of molecular data in lichen systematics provides an important alternative to traditional morphological characters for identifying natural groups and assessing evolutionary histories in challenging lichen taxa. In this work, I examined two common lichen-forming genera in western North America, Rhizoplaca and Xanthoparmelia, as models for investigating character evolution, species delimitation in morphologically and chemically diverse species, and identification of lineages in the early stages of divergence. Phylogenetic hypotheses were reconstructed to assess character evolution using sequence data from four nuclear ribosomal markers and fragments from two nuclear loci. I applied a multifaceted approach to delimit species in Rhizoplaca and Xanthoparmelia by assembling multiple lines of evidence using DNA sequence data, and genealogical and population genetic analyses. I have found that traditionally circumscribed species are not supported by molecular data. For example, in Rhizoplaca previously unrecognized lineages were identified within what has thus far been considered a single species. In contrast, morphologically and chemically distinct species within Xanthoparmelia were not supported by molecular data. Distinct medullary chemistries, growth forms, and the production of vegetative diaspores appear to have evolved independently multiple times in Xanthoparmelia. This work clearly indicates that morphological and chemical characters do not always accurately reflect lichen species diversity within even the best known and studied genera. My study of the Rhizoplaca melanophthalma species complex demonstrates that the genus Rhizoplaca, as presently circumscribed, is more diverse in western North American than previously thought. I present these analyses as a working example of species delimitation in morphologically cryptic lichenized fungi. In Xanthoparmelia diagnostic morphological and chemical characters have evolved in a highly homoplasious manner. In contrast to other studies documenting previously undiscovered fungal lineages masked within lichen species circumscribed by traditional morphological and chemical characters, my work suggests that species diversity has been overestimated in the lichen genus Xanthoparmelia.
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Athukorala, Sarangi. "Studies on the variability in reindeer lichens: the evolution of common North American species and thallus resynthesis in Cladonia rangiferina". NRC research Press, 2013. http://hdl.handle.net/1993/30311.
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Cladonia is one of the largest and widely distributed genera of lichen-forming fungi and some form the main winter diet for northern caribou and dominate the northern peatlands. Therefore, they are an ecologically important group of lichens. The ongoing climate change of the northern regions, impose challenges for lichen growth and algal interactions in these species. As in other organisms, genetic variability and phenotypic plasticity in the resynthesis of the lichen thallus will be important for their continued survival. The goal of my thesis is to better understand the variability of the reindeer lichens in an evolutionary and ecological context. Phylogenetic reconstruction (Chapter 2) together with genetic polymorphic studies with RAPD (Chapter 3) showed a lack of monophyly for 12 of 18 species of Cladonia and significant intraspecific genetic variation within the group. Genetic variation in the obligate fungal partner must also rely on the success of the symbiont interaction, which was further studied by resynthesis experiments. In vitro resynthesis experiments of C. rangiferina (Chapter 4) examined recognition- and defense-related genes of the symbionts of C. rangiferina using quantitative Polymerase Chain Reaction (qPCR) (Chapter 5) and suggested that the communication between partners occur and the survival and reestablishment of lichens in nature is affected by the presence of the compatible algal pool. This emphasizes the importance of finding the compatible algal partner for successful lichenization and suggests that parasitism and short-term interaction with incompatible algae may be a strategy allowing the fungus to survive until it finds a compatible algal partner. These studies also make parallels between the lichen symbiosis and plant pathogenic systems and provide molecular evidence for the parasitic nature of the lichen symbiosis. The collapse of the interaction between symbionts of C. rangiferina under varying temperature and pH conditions (Chapter 6) suggests the potential effect of habitat change on the reestablishment of lichens in nature. In summary, my Ph. D. research showed the importance of genetic and symbiotic versatility in an ecologically important species, using a model species in the group Cladonia and raised new questions for other lichen symbioses relevant to their life styles and habitats.
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Betts, C. J. "Synecological factors and processes of Calluna-lichen sub-communities at Hartlebury Common". Thesis, University of Worcester, 1990. http://eprints.worc.ac.uk/7125/.
Texto completoLibros sobre el tema "Common Lichens"
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Hutten, Martin. 101 common mosses, liverworts & lichens of the Olympic Peninsula. [Washington, D.C.?: National Park Service, 2001.
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Hutten, Martin. 101 common mosses, liverworts & lichens of the Olympic Peninsula. [United States?: s.n., 2001.
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Qian, Hong. Plants of British Columbia: Scientific and common names of vascular plants, bryophytes, and lichens. Vancouver: UBC Press, 1998.
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Rosentreter, Roger. A field guide to biological soil crusts of western U.S. drylands: Common lichens and bryophytes. Denver, Colo: U.S. Government Printing Office, 2007.
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1977-, Ranelletti Marla y McCourt Richard M. 1952-, eds. Common seaweeds of the Gulf of California =: Algas comunes del Golfo de California. Monterey, CA: Sea Challengers, 2005.
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Clair, Larry L. St. A color guidebook to common Rocky Mountain lichens. U.S. Forest Service, San Juan-Rio Grande National Forest, 1999.
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Klips, Robert. Common Mosses, Liverworts, and Lichens of Ohio: A Visual Guide. Ohio University Press, 2022.
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Heber, Howe Reginald. Common And Conspicuous Lichens Of New England: A Fieldbook For Beginners. Franklin Classics, 2018.
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Heber, Howe Reginald. Common and Conspicuous Lichens of New England: A Fieldbook for Beginners. Franklin Classics Trade Press, 2018.
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Readdie, Mark D., Marla Ranelletti y Richard M. Mccourt. Common Seaweeds of the Gulf of California. Sea Challengers, 2006.
Buscar texto completoCapítulos de libros sobre el tema "Common Lichens"
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Santiago, Krystle Angelique Aguda y Adeline Su Yien Ting. "Endolichenic Fungi from Common Lichens as New Sources for Valuable Bio-active Compounds". En Natural Bio-active Compounds, 105–27. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-7154-7_4.
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Lund, Katrín Anna. "Poetics of Nothingness: Ordering Wilderness". En Arctic Encounters, 35–60. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-41344-5_3.
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AbstractThis chapter takes the reader on a journey into the wilderness of Melrakkaslétta and follows the researcher who takes on the role of an explorer to rethink the potentiality of a place as a tourist destination. Selected encounters with features and figures whilst journeying are examined. What these have in common, although different in nature, is that they bring the flow of movement to a momentary, sometimes poetical, standstill which requires rethinking the order of things in an explorative manner. The features selected are: Beach Arctic terns Moss and lichens Modern ruin The aim is to examine how one can be in touch with the surroundings by allowing for the narratives they entail to emerge when moving with them. A beach reveals how heterogeneous materialities are moved about by natural forces which reflects on the constant rejuvenation that a place undergoes. Arctic terns provide a sense for constant renewal through seasonal changes and extreme mobile abilities. Moss and lichens bring one into direct touch with multispecies habitation that grows and nurtures, whilst modern ruins of a derelict farm give an insight into more-than-human co-habitation of flows and fluxes. These features represent mobile forces that constantly shape a place; a destination.
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Thomsen, S. "Lichen Sclerosus et Atrophicus". En Common Skin Diseases in Children, 63–65. Heidelberg: Steinkopff, 2003. http://dx.doi.org/10.1007/978-3-7985-1966-4_11.
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Shukla, Vertika, Ankita Asati, Devendra K. Patel, Manoj Semwal, Narendra Kumar y Dalip K. Upreti. "Metabolic Profiling and Its Plausible Environmental Significance in a Common Himalayan Lichen". En Plant Adaptation Strategies in Changing Environment, 235–51. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-6744-0_9.
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During, Heinjo J. "Ecological classifications of bryophytes and lichens". En Bryophytes and Lichens in a Changing Environment, 1–31. Oxford University PressOxford, 1992. http://dx.doi.org/10.1093/oso/9780198542919.003.0001.
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Abstract Attempts to classify plants using common characters or responses to the environment are as old as botany (cf. Barkman 1988). Apart from taxonomical classifications, plants have been grouped into chorological types, sociological and ecological species groups, growth-forms, life-forms, and life-history strategies. Such classifications are useful for making comparisons of the ecology of species and communities in different geographical regions (Smith 1982).
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Cheng, Thomas C. "Is parasitism symbiosis? A definition of terms and the evolution of concepts". En Parasite-Host Associations, 15–36. Oxford University PressOxford, 1991. http://dx.doi.org/10.1093/oso/9780198546481.003.0002.
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Abstract A common language in science is essential if investigators world-wide are to communicate. Here I re-examine what we mean by ‘parasitism’ and ‘symbiosis’ in the perspective of what is known today. The term ‘symbiosis’ was coined by Antoine de Bary in 1879. It literally means ‘living together’. De Bary was interested in the association between species of algae and fungi that form lichens. In his original definition (De Bary 1879), he did not include any suggestion of exchange of mutually beneficial factors between the algae and fungi; the term was coined strictly to define intimate heterospecific associations.
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Glime, Janice m. "Effects of pollutants on aquatic speci•es". En Bryophytes and Lichens in a Changing Environment, 333–61. Oxford University PressOxford, 1992. http://dx.doi.org/10.1093/oso/9780198542919.003.0013.
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Abstract Aquatic systems are likely to experience a much greater variety of changes, at least through human activity, than terrestrial systems. The increase of nutrients has created the most visible problems, resulting in algal blooms, loss of oxygen, decreasing fish populations, and ultimately depriving bryophytes and lichens of light. As in the terrestrial system, the decrease of pH and increase of heavy metals have caused more subtle changes, often favouring bryophytes over their vascular competitors. But in addition to those problems that are also experienced by terrestrial situations, the aquatic system can suffer from unique problems. Construction of dams alters flow regimes and can alter the dissolved substances as a result of oxygen depletion in the reservoir. Temperatures are likely to rise, not only as the result of the greenhouse effect, but also from deforestation, reservoirs, and heated effluents, creating problems for those organisms that are adapted to the previously existing narrow temperature range. Deforestation, agriculture, and construction increase turbidity, which may affect light intensities or cause abrasion. Organic pollutants, much more common in aquatic systems, can be toxic to selected members of the community.
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"Common Orange Lichen". En Bloom, 44. Liverpool University Press, 2021. http://dx.doi.org/10.2307/j.ctv1r1nr0g.32.
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Marks, Ronald y Richard Motley. "Psoriasis and lichen planus". En Common Skin Diseases, 138–58. CRC Press, 2019. http://dx.doi.org/10.1201/9780429196225-11.
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Sharma, Gayatri. "Microbes as Artists of Life". En Symbiosis in Nature [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.109532.
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Scientists have been knocking the wood to ascertain the symbiotic relationships of tiny living creatures, that is, microorganisms with other beings such as plants, animals, insects, and humans. The concept of “symbiosis” got its existence in 1879, which means “living together.” Microorganisms show a great deal of diverse interactions such as commensalism (moochers), mutualism (both benefitted), and parasitism (one benefitted and other unharmed) with other living beings and mutualism being the most common of all, thus forming a range of antagonistic to cooperative symbiotic relationships. These tiny creatures interact with plants by forming lichens (fungi and algae), mycorrhizae (plants and roots of higher plants), root noodles (Rhizobium) and acting as keyworkers in plant’s rhizosphere promoting growth and development. Microbial community also extends itself to kingdom Animalia establishing relationships with phylum Mammalia including humans, animals, and the most abundant species of phylum Arthropoda, that is, insects such as termites, which have colonization of bacteria in gut to digest wood cellulose. Scientists have discovered that most studied organisms—mussels found in deep-sea hydrothermal vents too live in a mutualistic association whereby bacteria get protection and mussels get nutrition as bacteria use chemicals from hydrothermal fluid producing organic compounds.
Actas de conferencias sobre el tema "Common Lichens"
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Sharma, Akanksha, Saritha Shamsunder, Geetika Khanna, Neeti Khunger y Vijay Zutshi. "Chronic vulval problems: A gynaecologist’s perspective". En 16th Annual International Conference RGCON. Thieme Medical and Scientific Publishers Private Ltd., 2016. http://dx.doi.org/10.1055/s-0039-1685355.
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Introduction: Chronic vulval symptoms are common complaints in women seeking health care and can significantly interfere with a woman’s sexual function and sense of well being. Many practitioners feel diagnostically challenged, particularly by chronic or recurrent forms of vulval disease. The aim of this study was to assess the role of various diagnostic modalities in evaluation of chronic vulval symptoms. Methods: Between August 2012 and February 2014, 100 women presenting with chronic vulval symptoms (i.e. ≥ 3 months duration) were evaluated. All of them had a thorough clinical history taken including use of vulval washes and creams, a general and gynaecological examination. Patients having chronic vaginal discharge in addition had urethral, vaginal and cervical smear and culture. All women had a careful examination of the vulva with and without magnification. Vulval scrape cytology was taken after moistening the vulva with normal saline and stained by Pap stain. Colposcopy of the vulva was then carried out after applying 5% acetic acid and 1% toluidine blue dye. Vulval biopsy was taken from suspicious areas on colposcopy and further management was based on histopathology report. Results: The mean age of women in our study was 43.57 years (range 22-80 years.), 70% women were pre-menopausal and 30% were post-menopausal. The mean duration of symptoms was 1.625 years (range 6 months - 15 years) and atypical vulval hygiene practices (excessive washing with soaps) was used in 77% of women. The commonest presenting complaint was pruritus in 92% of women; visible lesions on vulva were seen in 20%, pain in 6% and burning sensation in vulva in 5% of women. The histopathology was abnormal in 77 patients; the most common histopathological finding was non-neoplastic epithelial disorders in 64 women {Squamous cell hyperplasia (n=52), Lichen Sclerosus et atrophicus (n=6), other dermatoses including lichen Planus (n=6)}. Vulvar Intra-epithelial Neoplasia (VIN) was seen in 6 patients, 5 were squamous type VIN and 1 was non-squamous type (Paget’s disease). Squamous cell carcinoma was seen in 3 patients; malignant melanoma, benign appendiceal tumor, angiofibroma and neurofibroma in 1 patient. Examination without magnification had sensitivity of 25.97% and with magnification was 29.87% and specificity was 100% for both of them. Cytology had sensitivity and specificity of 75.32% and 86.95% respectively and sensitivity and specificity of colposcopy was 77.92% and 17.39% respectively. Conclusion: Clinical examination with and without magnification had low sensitivity but were highly specific in diagnosing vulvar lesions. A normal vulval smear and colposcopy have a high negative predictive value and are very reassuring. Colposcopy and biopsy is the gold standard for diagnosis, however clinical examination with naked eyes and magnifying glass are invaluable and can diagnose most of the neoplastic lesions.
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Lavoie, Andrew. "Lichten Award Paper: Variational Tolerance Analysis (VTA) - Design and Manufacturing Optimization Using Statistical Simulation". En Vertical Flight Society 77th Annual Forum & Technology Display. The Vertical Flight Society, 2021. http://dx.doi.org/10.4050/f-0077-2021-16817.
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Appropriate consideration of tolerances is critical to the design and manufacture of products that meet customer requirements and defined cost targets. Tolerance analysis is most commonly conducted at the individual part or sub-assembly level utilizing basic stack-up methods (worst-case analysis) to ensure the producibility of the assembled product. A worst-case analysis assumes that each dimension in the stack-up will be manufactured on the extreme end or limit of its assigned tolerance (max or min) in such a way that all tolerances become additive. This usually results in tighter than required drawing tolerances being assigned to guarantee the product can be assembled. Modern day manufacturing processes focus on targeting the nominal dimensional value, so it is safe to assume that a higher number of parts will be produced closer to the nominal value than parts produced at the extreme end of the tolerance range. When evaluating the tolerance stack-up of a larger assembly with many parts additional tolerance analysis methods apply (Root Sum Squared, RSS), and a worst-case analysis becomes more costly and less meaningful. The RSS method of tolerance analysis takes into consideration manufacturing targets and applies normal distribution methods to assess more likely tolerance results, allowing relaxed drawing tolerances to be assigned while still maintaining a high level of confidence in a successful assembly. For analysis of complex systems or installations, tolerance studies using more sophisticated approaches to deal with variation such as Monte Carlo statistical analysis is required. Variational Tolerance Analysis (VTA) tools available today allow a typical Monte Carlo tolerance simulation to be visualized by the designer through 3-dimensional real time manufacturing simulations and sensitivity analysis. This in turn simplifies the development process and allows better identification of tolerance drivers within a large system installation; analysis of the geometric effect of tolerances within the installation; and the ability to quickly iterate the analysis to optimize designs for producibility and lower cost. In this paper, the use of VTA is assessed and quantified to form a business case for further investment by Lockheed Martin. In the course of this work, VTA has been evaluated both before and after final designs were released to manufacturing. Before final designs are released VTA can be used for design optimization (i.e. build before you build simulations), part sequencing studies, or to gain insight into the assembly/installation process enabling advanced planning to take place up front. VTA can also address challenges discovered after final designs have been released to manufacturing and parts are on hand (i.e. during the build) such as: assembly issues, out of spec part disposition, and to inform manufacturing of any special tooling or part rework considerations aiding in corrective action or risk mitigation plans. Cost savings to the business due to the implementation of VTA has been demonstrated in 4 distinct ways: 1.Reduced design revisions – Design optimization up front reduces future revisions caused by producibility and tolerance related discoveries. 2.Manufacturing – Through tolerance optimization, nonimpactful tolerances can be relaxed while still ensuring a successful assembly. 3.Reduced build schedule – Increased assembly awareness and advanced planning allows a streamlined production process with risk mitigation strategies in place. 4.Reduced scrap, rework, repair (SRR) – Engineering labor to disposition out of spec parts is reduced by entering as-measured tolerances into the simulation model to assess the overall impact to installation success. The conclusion is VTA simulations provide measurable benefits to the business through robust design optimization, and multi-layered cost and risk reductions.
Informes sobre el tema "Common Lichens"
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Swan, Megan y Christopher Calvo. Site characterization and change over time in semi-arid grassland and shrublands at three parks?Chaco Culture National Historic Park, Petrified Forest National Park, and Wupatki National Monument: Upland vegetation and soils monitoring 2007?2021. National Park Service, 2024. http://dx.doi.org/10.36967/2301582.
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This report presents results of upland vegetation and soil monitoring of semi-arid grasslands at three Parks by the Southern Colorado Plateau Inventory and Monitoring Network (SCPN) from 2007?2021. The purpose is to compare and contrast five grassland ecological sites and examine how they have changed during the first 15 years of monitoring. Crews collected data on composition and abundance of vegetation, both at the species level and by lifeform (e.g., perennial grass, shrub, forb) and soil aggregate stability and soil texture at 150 plots within five target grassland/shrubland communities delineated using NRCS ecological site (ecosite) classification (30 plots per ecosite). Soils in plots at Petrified Forest NP and Chaco Culture NHP were deeper than those at Wupatki NM. Undifferentiated soil crust comprised the largest component of the soil surface, except at Wupatki where surface gravel dominated. Cover of biological soil crust (cyanobacteria, lichen, and moss) was low. Soil aggregate stability was moderate. From 2007?2021, SCPN crews identified 283 unique plant species. Overall live foliar cover ranged from 12-24%. Four of five ecological sites were dominated by C4 grass species (>70% of total live foliar cover). Shrubs co-dominated at one site (WUPA L) and forbs were an overall small component of total vegetation cover but contributed most of the diversity in these sites. Less than 4% of species detected were nonnative. Russian thistle (Salsola tragus) was the most frequently sampled nonnative, occurring in > 50% of plots at Wupatki in the volcanic upland ecological site. Cheatgrass (Bromus tectorum) was the second most common invasive species but occurred in < 10% of the plots at all ecological sites. Vegetation cover was modeled using Bayesian hierarchical models and included seasonal climatic water deficits, year effects and topographic variables as covariates. Models revealed significant negative time trends (i.e., changes over time that were not explained by changes in seasonal deficit covariates included) in some modeled responses, particularly in the cover of perennial grass at all five ecological sites. Time trends in shrub and forb responses were mixed. Species richness showed variable effects by ecosite, decreasing at CHCU S, and increasing at PEFO S and WUPA V. Modeled responses were influenced by climate covariates, but direction of these effects varied. The most consistent effects were that greater July water stress and higher accumulated growing degree days (i.e., warmer spring temperatures) increased cover of perennial grasses and shrubs during the same year. However, greater water stress in the spring had a negative effect on many responses as expected. Decreasing cover of perennial grass and increasing cover of shrubs and weedy forbs has been predicted for southwestern grasslands in response to increasing aridification due to anthropogenic climate change. Perennial grass trends reported here correspond with these predictions with mixed results on shrub and forb community trends. Continued drought conditions will likely exacerbate negative changes in these systems.
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Inventory of lichen and bryophyte communities in the Yeon Unit of Lewis and Clark National Historical Park: Final report. National Park Service, 2023. http://dx.doi.org/10.36967/2301457.
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The 106-acre Yeon Unit of Lewis and Clark National Historic Park lies along the immediate coast eight miles north of Seaside, Oregon. The primary objective of these surveys was to capture the complete lichen and bryophyte flora of the Yeon property with focus on the remnant prairies and the salix swamp, report on any rare species observed or collected, and document the extent and population size of the rare lichen, Pannaria rubiginosa. Surveys were conducted in December 2021 and January 2022. While this report sufficiently characterizes the lichen and bryophyte flora of the Yeon property, it is not sufficient for the Sunset property. For a complete list of the non-vascular flora of the Sunset property, a more intentional survey should be conducted. Of the 46 bryophyte species recorded, none of them are considered rare by ORBIC. The species checklist reflects a bryoflora typical of Pacific Northwest coastal dune ecosystems. The collection of Dicranum rhabdocarpum needs to be verified as it is rare in Oregon and there is low confidence in the species level determination of it. The invasive moss, Camplylopus introflexus, was found throughout the site in impacted areas especially where fire management had been conducted. This moss should be monitored as it has spread throughout most areas of the dune and may displace native bryophytes and complicate ecological succession in fire/restoration areas. Lichens were found throughout the 106-acre Yeon unit, although in varying density and diversity. The fore dunes adjacent to the open sand area of the coast historically hosted the coastal prairie habitat but now this area was almost completely infested with the invasive beachgrasses Ammophila arenaria and A. breviligulata. In this area these xerophytic Ammophila species occupied nearly 100% of the terrestrial habitat and there were no trees or shrubs to provide arboreal lichen habitat. There were a few small patches of remnant prairie within the swaths of Ammophila spp. that were generally smaller than 10m?. In these areas the lichens were dominated by Cladonia, Peltigera and Scytinium species. In general, the shore pine habitat that has not been recently thinned had a dense canopy and therefore the surveyable lichen habitat had very low rates of lichen colonization. The exceptions were the areas with edge effects. The west side facing the foredunes hosted a few arboreal species. Light gaps within this forest had minimal arboreal and terrestrial species colonization. Thinned shore pine plantations had a slightly higher concentration of species richness and increased biomass due to the abundance of light that penetrates to the surveyable habitat. These were limited to fairly common species in genera such as Hypogymnia, Platismatia, and Usnea. The area with the richest lichen diversity was in the interdunal wetland and willow swamp areas. These habitats had rich and well developed cyanolichen communities.