Search results for "Gram"
showing 10 items of 9069 documents
The river harbour of Ostia Antica - stratigraphy, extent and harbour infrastructure from combined geophysical measurements and drillings
2018
Abstract We performed a combined geophysical and geoarchaeological survey of the harbour of ancient Ostia, Italy, to investigate the extent of the former harbour basin, the sedimentary infill and possible building remains around the harbour. Besides geoarchaeological results the paper highlights the advantage of combining vibracore drilling with different geophysical prospection methods, which are sensitive to different physical soil parameters. Geophysical methods applied were electrical resistivity tomography (ERT), ground penetrating radar (GPR) and seismics with shear and compressional waves. The extent and shape of the harbour basin were determined by ERT profiling. The ERT profiles we…
A multisensor fusion approach to improve LAI time series
2011
International audience; High-quality and gap-free satellite time series are required for reliable terrestrial monitoring. Moderate resolution sensors provide continuous observations at global scale for monitoring spatial and temporal variations of land surface characteristics. However, the full potential of remote sensing systems is often hampered by poor quality or missing data caused by clouds, aerosols, snow cover, algorithms and instrumentation problems. A multisensor fusion approach is here proposed to improve the spatio-temporal continuity, consistency and accuracy of current satellite products. It is based on the use of neural networks, gap filling and temporal smoothing techniques. …
An improved understanding of the Alaska Coastal Current: the application of a bivalve growth-temperature model to reconstruct freshwater-influenced p…
2011
Shells of intertidal bivalve mollusks contain sub-seasonally to interannually resolved records of temperature and salinity variations in coastal settings. Such data are essential to understand changing land-sea interactions through time, specifically atmospheric (precipitation rate, glacial meltwater, river discharge) and oceanographic circulation patterns; however, independent temperature and salinity proxies are currently not available. We established a model for reconstructing daily water temperatures with an average standard error of ∼1.3 °C based on variations in the width of lunar daily growth increments of Saxidomus gigantea from southwestern Alaska, United States. Temperature explai…
Towards LST split-window algorithm FPGA implementation for CubeSats on-board computations purposes
2019
ABSTRACTNano, pico, and the so-called CubeSat satellites are taking place due to the emergent improvements in both high-performance nano and pico electronics and computational technologies. More th...
The key role played by the Augusta basin (southern Italy) in the mercury contamination of the Mediterranean Sea.
2011
The Augusta basin, located in SE Sicily (southern Italy), is a semi-enclosed marine area, labelled as a highly contaminated site. The release of mercury into the harbour seawater and its dispersion to the blue water, make the Augusta basin a potential source of anthropogenic pollution for the Mediterranean Sea. A mass balance was implemented to calculate the HgT budget in the Augusta basin. Results suggest that an average of ∼0.073 kmol of HgT is released, by diffusion, on a yearly basis, from sediments to the seawater, with a consequent output of 0.162 kmol y(-1) to coastal and offshore waters; this makes the Augusta area an important contributor of mercury to the Mediterranean Sea. Owing …
First M87 Event Horizon Telescope Results. II. Array and Instrumentation
2019
The Event Horizon Telescope (EHT) is a very long baseline interferometry (VLBI) array that comprises millimeter- and submillimeter-wavelength telescopes separated by distances comparable to the diameter of the Earth. At a nominal operating wavelength of ~1.3 mm, EHT angular resolution (λ/D) is ~25 μas, which is sufficient to resolve nearby supermassive black hole candidates on spatial and temporal scales that correspond to their event horizons. With this capability, the EHT scientific goals are to probe general relativistic effects in the strong-field regime and to study accretion and relativistic jet formation near the black hole boundary. In this Letter we describe the system design of th…
Holocene climate and seasonality of shell collection at the Dundas Islands Group, northern British Columbia, Canada—A bivalve sclerochronological app…
2013
article i nfo To analyze environmental changes and the seasonality of shell collection in British Columbia during the Ho- locene, oxygen isotopes were measured from modern and archeological (1337-7438 cal yr BP) shells of the butter clam Saxidomus gigantea. 1697 discrete isotope samples were taken from two modern and 27 arche- ological shells with a high temporal resolution (sub-seasonal up to daily). Archeological shells were collected from five shell midden sites on the Dundas Islands Group, northern British Columbia, Canada. The oxygen iso- tope data reveal clear annual cycles, with the most positive δ 18 Oshell values occurring during the cold season (slower growth, annual growth line f…
Social Lives of Monumental Walls: Hunting along the Upper Tigris
2021
On the left bank of the Tigris in northern Iraq, in an area today partially flooded by the Mosul Dam reservoir, lies an enigmatic monumental enclosure known in the literature as the “Tigris Wall.” Before its partial submersion under the waters of the modern lake, the large L-shaped embankment, about 4 × 4 km long, enclosed an area of ca. 1600 ha, overlooking the Tigris and its alluvial plain. By means of a holistic strategy that includes different levels of analysis (remote sensing, pedestrian and UAV photogrammetric surveys, excavation, and settlement pattern analysis), this paper addresses the structure, its context, and its environment. Relying on the results of this multi-disciplinary a…
Unmanned Aerial Vehicle (UAV) Survey with Commercial-Grade Instruments: A Case Study from the Eastern Ḫabur Archaeological Survey, Iraq
2018
Low-altitude photography in archaeology is now common practice at the scale of excavations; however, landscape-scale applications are a relatively new endeavor with promising analytical potential. From 2014–2016, an unmanned aerial vehicle (UAV) with a mounted camera was used to document sites recorded as part of the Eastern Ḫabur Archaeological Survey (EḪAS), an archaeological reconnaissance project in western Dohuk Province, Iraqi Kurdistan. The EḪAS team documented over 70 archaeological sites with the UAV, from single-phase artifact scatters, to archaeological remains with standing architecture, to tells that cover more than 30 hectares. Representative examples from this survey are pres…
Seasonality and Intensity of Shellfish Harvesting on the North Coast of British Columbia
2013
ABSTRACT Biogeochemical and growth increment analyses show contrasting seasonal patterns of butter clam collection and rates of harvest intensity between archaeological shell midden sites from the Dundas Islands archipelago and the mainland coast in Prince Rupert Harbour, northern British Columbia. Growth increment analysis shows more intensive clam harvest in the Dundas Islands in comparison to the residential sites in Prince Rupert Harbour. Stable oxygen isotope analysis shows multi-seasonal collection of clams in the Dundas Islands and a more seasonally specific emphasis in Prince Rupert Harbour. Comparison of these results to those of similar studies in the Namu region on the central co…