نتایج جستجو برای: trace fossil

تعداد نتایج: 91986  

Journal: :Geoscientific Model Development 2022

Abstract. WOMBAT (the WOllongong Methodology for Bayesian Assimilation of Trace-gases) is a fully hierarchical statistical framework flux inversion trace gases from flask, in situ, and remotely sensed data. extends the conventional synthesis through consideration correlated error term, capacity online bias correction, provision uncertainty quantification on all unknowns that appear model. We sh...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2005
Yong-Sheng Li Cheng-Xia Xing Li-Ling Yang

A new method for the rapid determination of trace-level sodium ion based on flow-injection analysis (FIA) and an ion selective electrode (ISE) is proposed. Various effects on the sensitivity of the method such as the flow rate and alkalinity of the carrier, sampling volume, temperature, length of reaction coil, length and thickness of alkalization tube, concentration of the alkalizing reagent e...

Journal: :Current Biology 2000
Tomas Lindahl

Also known as... ancient DNA. The New Shorter Oxford Dictionary offers the precise explanation of ‘ancient’ as ‘belonging or pertaining to the period before the fall of the Western Roman Empire in AD 476.’ DNA can be recovered from fossils much older than 1500 years, but the inevitable time-dependent decay of the DNA structure due to oxidation and hydrolysis makes retrieval increasingly difficu...

Journal: :Biological reviews of the Cambridge Philosophical Society 2010
Paul A Selden David Penney

Over the last three decades, the fossil record of spiders has increased from being previously biased towards Tertiary ambers and a few dubious earlier records, to one which reveals a much greater diversity in the Mesozoic, with many of the modern families present in that era, and with clearer evidence of the evolutionary history of the group. We here record the history of palaeoarachnology and ...

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2009
Richard Nehring

During the past century, fossil fuels--petroleum liquids, natural gas and coal--were the dominant source of world energy production. From 1950 to 2005, fossil fuels provided 85-93% of all energy production. All fossil fuels grew substantially during this period, their combined growth exceeding the increase in world population. This growth, however, was irregular, providing for rapidly growing p...

2009
Richard Nehring

During the past century, fossil fuels—petroleum liquids, natural gas and coal—were the dominant source of world energy production. From 1950 to 2005, fossil fuels provided 85–93% of all energy production. All fossil fuels grew substantially during this period, their combined growth exceeding the increase in world population. This growth, however, was irregular, providing for rapidly growing per...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1976
S Weiner H A Lowenstam L Hood

Fossil glycoproteins of the soluble organic matrix are present in an 80-million-year-old mollusk shell from the Late Cretaceous Period. Discrete molecular weight components, as determined by gel electrophoresis, are preserved. The fossil organic matrix was compared with the organic matrix of a living representative species of the same superfamily. A particular repeating amino acid sequence, fou...

Journal: :Evolution; international journal of organic evolution 2005
Thomas J Near Daniel I Bolnick Peter C Wainwright

Molecular clock methods allow biologists to estimate divergence times, which in turn play an important role in comparative studies of many evolutionary processes. It is well known that molecular age estimates can be biased by heterogeneity in rates of molecular evolution, but less attention has been paid to the issue of potentially erroneous fossil calibrations. In this study we estimate the ti...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید