نتایج جستجو برای: trace fossil

تعداد نتایج: 91986  

Habib G. Khosroshahi, Louisa A. Nolan

It is inferred from the symmetrical and luminous X-ray emission of fossil groups that they are mature, relaxed galaxy systems. Cosmological simulations and observations focusing on their dark halo and inter-galactic medium properties confirm their early formation. Recent photometric observations suggest that, unlike the majority of non-fossil brightest group galaxies (BGGs), the central early-t...

2002
KATHERINE M. MOORE MAttHEW L. MURRAY

-Several methods for assessing the preservation of the organic and inorganic components of bone are discussed. Aspects of bone composition (i.e. specific trace element concentrations and stable isotope ratios) provide information on diet and health status in prehistoric and fossil humans. Such information is valuable in understanding the evolution of human adaptation but, prior to the analysis ...

Journal: :Systematic biology 2009
John J Wiens

The genomics revolution offers great promise for resolving the phylogeny of living taxa, but does it offer any benefits for reconstructing relationships among extinct (fossil) taxa? Superficially, the answer would seem to be "no," given that molecular data cannot be obtained for most fossil taxa. However, because fossil taxa often interdigitate among living taxa on the Tree of Life, molecular d...

2016
Adam Smoliński Natalia Howaniec

The significance of coal in the world economy remains unquestionable for decades. It is also expected to be the dominant fossil fuel in the foreseeable future. The increased awareness of sustainable development reflected in the relevant regulations implies, however, the need for the development and implementation of clean coal technologies on the one hand, and adequate analytical tools on the o...

2008
Laura V. Sales Julio F. Navarro Diego G. Lambas Simon D. M. White Darren J. Croton

We use a semianalytic galaxy catalogue constructed from the Millennium Simulation (MS) to study the satellites of isolated galaxies in the ΛCDM cosmogony. The large volume surveyed by the MS (500 hMpc), together with its unprecedented numerical resolution, enable the compilation of a large sample of ∼ 80, 000 bright (Mr < −20.5) primaries, surrounded by ∼ 178, 000 satellites down to the faint m...

Journal: :iranian journal of radiation research 0
j. salimi department of surgery, sina hospital, tehran university of medical sciences, tehran, iran k. moosavi s. vatankhah a. yaghoobi

background: within the context of developing techniques to facilitate the diagnosis of the thyroid diseases, the elemental composition of pathological thyroid tissue (neoplastic and non-neoplastic) was investigated by proton induced x-ray emission. the pixe has been widely used as a sensitive technique for trace elemental analysis in both biological and medical fields. materials and methods: th...

Journal: :acta medica iranica 0
s. h. emami-razavi n. esmaeili s. k. forouzannia s. amanpour s. rabbani a. m. alizadeh m. a. mohagheghi

wound healing in the skin depends upon the availability of appropriate trace metals as enzyme cofactors and structural components in tissue repair. the present study is a part of a series of experimental investigations to examine the influence of bentonite on skin wound healing. surgically induced skin wounds in 48 young adult male rats were exposed topically to bentonite (12 round wound and 12...

2017
Sam W Heads Andrew N Miller J Leland Crane M Jared Thomas Danielle M Ruffatto Andrew S Methven Daniel B Raudabaugh Yinan Wang

A new fossil mushroom is described and illustrated from the Lower Cretaceous Crato Formation of northeast Brazil. Gondwanagaricites magnificus gen. et sp. nov. is remarkable for its exceptional preservation as a mineralized replacement in laminated limestone, as all other fossil mushrooms are known from amber inclusions. Gondwanagaricites represents the oldest fossil mushroom to date and the fi...

Journal: :American journal of botany 2008
Fabiany A Herrera Carlos A Jaramillo David L Dilcher Scott L Wing Carolina Gómez-N

Both the fossil record and molecular data support a long evolutionary history for the Araceae. Although the family is diverse in tropical America today, most araceous fossils, however, have been recorded from middle and high latitudes. Here, we report fossil leaves of Araceae from the middle-late Paleocene of northern Colombia, and review fossil araceous pollen grains from the same interval. Tw...

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