Results 51 to 60 of about 247,032 (194)

Exploring the Psychological Basis for Transitions in the Archaeological Record [PDF]

open access: yesIn Tracy B. Henley, Matthew Rossano, and Edward P. Kardas (Eds.) Handbook of Cognitive Archaeology: A Psychological Framework. (2019), 2018
In lieu of an abstract here is the first paragraph: No other species remotely approaches the human capacity for the cultural evolution of novelty that is accumulative, adaptive, and open-ended (i.e., with no a priori limit on the size or scope of possibilities).
arxiv  

Archaeology of active galaxies across the electromagnetic spectrum [PDF]

open access: yesarXiv, 2017
Analytical and numerical galaxy-formation models indicate that active galactic nuclei (AGNs) likely play a prominent role in the formation and evolution of galaxies. However, quantifying this effect requires knowledge of how the nuclear activity proceeds throughout the life of a galaxy, whether it alternates with periods of quiescence and, if so, on ...
arxiv  

Astro2020 Science White Paper: Local Dwarf Galaxy Archaeology [PDF]

open access: yesarXiv, 2019
Nearby dwarf galaxies are local analogues of high-redshift and metal-poor stellar populations. Most of these systems ceased star formation long ago, but they retain signatures of their past that can be unraveled by detailed study of their resolved stars.
arxiv  

Competitive mapping allows for the identification and exclusion of human DNA contamination in ancient faunal genomic datasets

open access: yesBMC Genomics, 2020
Background After over a decade of developments in field collection, laboratory methods and advances in high-throughput sequencing, contamination remains a key issue in ancient DNA research.
Tatiana R. Feuerborn   +14 more
doaj   +1 more source

Physics of Leap Second [PDF]

open access: yesarXiv, 2009
The physical origin of the leap second is discussed in terms of the new gravity model. The calculated time shift of the earth rotation around the sun for one year amounts to $\displaystyle{\Delta T \simeq 0.621 s/ year}$. According to the data, the leap second correction for one year corresponds to $\Delta T \simeq 0.63 \pm 0.03 s/ year $, which is in ...
arxiv  

Stellar Archaeology: New Science with Old Stars [PDF]

open access: yesarXiv, 2010
The abundance patterns of metal-poor stars provide us a wealth of chemical information about various stages of cosmic chemical evolution. In particular, these stars allow us to study the formation and evolution of the elements, and the involved nucleosynthesis processes.
arxiv  

Phenotypic and genetic variation within the Cricotopus sylvestris species-group (Diptera, Chironomidae), across a Nearctic - Palaearctic gradient

open access: yesFauna Norvegica, 2012
Intraspecific variation sometimes obscures species boundaries and makes identification of certain Chironomidae difficult. This is true for many species in the genus Cricotopus. We used DNA barcode data and multivariate statistical analyses to investigate
Susan Gresens   +2 more
doaj   +1 more source

Olmec mirrors: an example of archaeological American mirrors [PDF]

open access: yesarXiv, 2007
Archaeological mirrors from the Olmec civilization are described according to bibliographic references and to personal observations and photographs.
arxiv  

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