Results 121 to 130 of about 78,431 (269)

Optimal timing and rate of nitrogen fertilizer use: An integrated network technology approach

American Journal of Agricultural Economics, EarlyView.
Abstract Both the rate and timing of crop fertilizer application play an important role in agricultural productivity. However, inefficient fertilizer use can significantly increase production costs, water pollution, and greenhouse gas emissions. To capture both the spatial heterogeneity and dynamic nature of this problem, we develop a multi‐stage ...
Tihomir Ancev, Moriah Bostian
wiley   +1 more source

Age-dependent seismic thickness and mechanical strength of the Australian lithosphere [PDF]

, 2002
We present constraints on the regional variations of the seismic and mechanical thickness of the Australian lithosphere. We infer the seismic thickness from a waveform tomographic model of S-wave speed, and as a proxy for the elastic thickness we use the
Simons, FJ, van der Hilst, RD
core  

The exploitation of silver deposits in early medieval Europe: some documentary, economic and social problems

Archaeometry, EarlyView.
Abstract Focusing on Southern Europe, this article sheds light on the mining landscape of the early Middle Ages. Based on the current state of historical and archaeological knowledge, the article raises a number of questions that can be extended to other European regions.
Nicolas Minvielle Larousse
wiley   +1 more source

Lithic analysis in African archaeology: Advances and key themes

Archaeometry, EarlyView.
Abstract Stone artifacts (lithics) preserve for extended periods; thus they are key evidence for probing the evolution of human technological behaviors. Africa boasts the oldest record of stone artifacts, spanning 3.3 Ma, rare instances of ethnographic stone tool‐making, and stone tool archives from diverse ecological settings, making it an anchor for ...
Deborah I. Olszewski, Amanuel Beyin, Justin Pargeter   +2 more
wiley   +1 more source

A geochemical modeling approach in Lardosa region (Castelo Branco): an environmental management tool [PDF]

, 2013
Comunicação oral da qual só está disponível o resumo.A geochemical modeling approach in Lardosa region (Castelo Branco): an environmental management ...
Albuquerque, M.T.D., Antunes, I.M.H.R., Sanches, F.   +2 more
core  

The Provenance of Silver in the Viking‐Age Hoard From Bedale, North Yorkshire

Archaeometry, EarlyView.
ABSTRACT The acquisition of silver was a key motive propelling the Viking expansion out of Scandinavia; identifying the sources of Viking silver during the early part of the Viking Age can provide critical insights into the relative significance of western European and eastern, Islamic wealth in the Viking expansion.
Jane Kershaw, Stephen Merkel, Andrew Woods, Jane Evans, Vanessa Pashley, Simon Chenery   +5 more
wiley   +1 more source

New Geothermal Prospect in North-Eastern Morocco [PDF]

, 2010
Geothermal data has been indicating promising potentialities in the north-eastern Morocco. This paperpresents new temperature data, recently recorded in water borehole located in the Berkane and Oujda areas.
Barkaoui, Alae Eddine, Boughriba, Mimoun, Carneiro, Júlio, Correia, António, Lucazeau, Francis, Rimi, Abdelkrim, Verdoya, Massimo, Zarhloule, Yassine   +7 more
core  

An Archaeometallurgical Investigation on Some Archaeological Metal Finds From the Sasanian Site of Jahāngir, Western Iran

Archaeometry, EarlyView.
ABSTRACT Twelve metal artifacts from recent excavations at the Sasanian archaeological site of Jahāngir in western Iran have been analyzed. These items include both decorative and utilitarian artifacts. The samples were examined using micro‐X‐ray fluorescence (μ‐XRF), scanning electron microscopy with energy‐dispersive X‐ray spectroscopy (SEM‐EDS), and
Omid Oudbashi, Leila Khosravi, Morteza Habibzadeh   +2 more
wiley   +1 more source

Variations in Hawaiian Plume Flux Controlled by Ancient Mantle Depletion

AGU Advances
Mantle plumes—upwellings of buoyant rock in Earth's mantle—feed hotspot volcanoes such as Hawai‘i. The size of volcanoes along the Hawai‘i–Emperor chain, and thus the magma flux of the Hawaiian plume, has varied over the past 85 million years.
Paul Béguelin, Andreas Stracke, Maxim D. Ballmer, Shichun Huang, Michael Willig, Michael Bizimis   +5 more
doaj   +1 more source

Fecal Steroids as Tracers of Human Population and Waste Management Practices at the Ancient Maya City of Ucanal, Guatemala

Archaeometry, EarlyView.
ABSTRACT Geochemical data compiled from dried sediments from three water reservoirs at the ancient Maya city of Ucanal, Petén, Guatemala, reveal low to undetectable fecal biomarker concentrations. These low concentrations may be the result of the aerobic decay of sterols combined with well‐managed waste disposal practices.
Jean D. Tremblay, Peter M. J. Douglas, Christina T. Halperin, Yves Gélinas   +3 more
wiley   +1 more source