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Sea surface temperature reconstruction of ODP Site 175-1087
No full textSuccessful application of the alkenone palaeothermometer, the UK'37 index, relies upon the assumption that fossil alkenone synthesisers responded to growth-temperature changes in a similar manner to the modern producers, chiefly the coccolithophores Emiliania huxleyi and Gephyrocapsa oceanica. We compare coccolith and UK'37 data from ODP Site 1087 in the south-east Atlantic between 1500 and 500 ka, and show that evolutionary events and changes in species dominance within the coccolithophore populations had little impact on the UK'37 record. The relative abundances of the C37 and C38 alkenones also closely resembled those found in modern populations, and suggest a similar temperature sensitivity of UK'37 during the early and mid-Pleistocene to that found at present. These results support the application of the UK'37 index to reconstruct sea-surface temperatures (SSTs) throughout the Quaternary.
The UK'37 record at ODP Site 1087 contains an SST signal that documents the emergence of the 100-kyr cycles that characterise the late Quaternary ice volume records. This is preceded by significant cooling at ODP Site 1087, marked by a negative shift in SSTs and a positive shift in the planktonic delta18O some 250-kyr earlier, at ca 1150-1000 ka. This results in a permanent fall in average SSTs of around 1.5 °C. The predicted increase in aridity onshore as a result of this cooling can be identified in a number of published records from southern Africa, and may have played a role in some important evolutionary events of the mid-Pleistocene
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(Table T1) Percentages of CaCO3, TOC, TN, TS of Site 175-1087
No full textSite 1087 is located on the continental rise of southwest Africa at a water depth of 1371 m in the southern part of the Cape Basin. The site is part of the suite of Africa margin locations drilled during Leg 175 to reconstruct the onset and evolution of the elevated biological productivity associated with the Benguela Current upwelling system. Measurements of the amounts of inorganic and organic carbon that have accumulated in sediment under this major coastal upwelling regime are essential to this reconstruction, and these were routinely done for the first 12 sites occupied during Leg 175. However, determinations of calcium carbonate and organic carbon concentrations in sediments from Site 1087 had to be deferred to postcruise analysis because the JOIDES Resolution (JR) entered Cape Town 1 day after completing this site.
Sediment samples were collected at intervals of three per core from Hole 1087A and the lower part of Hole 1087C to provide a survey of the histories of post-Eocene accumulation of calcium carbonate and organic carbon at this site. The samples were freeze-dried on the ship in preparation for subsequent shore-based analysis. Concentrations of calcium carbonate and organic carbon in the sediment samples were measured at the University of Michigan after the cruise. Organic matter atomic C/N ratios were employed to infer the origin of the organic matter contained within the sediments and to explore some of the factors affecting its preservation and accumulation
Santa Fe (ATSF) 1087
No full textA photograph print showing the Santa Fe (ATSF) 1087, 2-6-2 (BLW, class 1050), at Clinton, OK
Struttura e mani del Vat. gr. 1087 (con note paleografiche sul copista C e il Marc. gr. 330).
No full textAnalisi codicologica e paleografica del Vat. gr. 1087, confronto con il Marc. gr. 330, attribuito al copista C del codice Vaticano e contenente un excerptum da una edizione PHI di Arat
L’apparato iconografico del codice Vat. gr. 1087. Per la ricostruzione dell’edizione tardoantica del corpus arateo
No full textIl capitolo propone una lettura delle immagini contenute nel codice Vat. gr. 1087, con un duplice intento: da un lato,stabilire il posto occupato dal nostro manoscritto all’interno della tradizione aratea, testimoniata dalle illustrazioni di numerosi codici astronomici, soprattutto latini; dall’altro, individuare il momento in cui venne canonizzata la versione di questo corpus di immagini divenuta poi normativa, destinata ad avere immensa fortuna nel Medioevo occidentale
C. femoratus Alignment ant.1087
No full textAlignment of nuclear marker "ant.1087", Camponotus femoratu
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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