نتایج جستجو برای: trace fossil
تعداد نتایج: 91986 فیلتر نتایج به سال:
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...
-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 ...
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...
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...
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...
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...
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...
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...
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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