Stable isotope analysis on sediment core RC11-86

Oxygen isotope measurements have been made in foraminifera from over 60 deep-sea sediment cores. Taken together with the oxygen isotope measurements published by Emiliani from Caribbean and Equatorial Atlantic cores, this comprises a unique body of stratigraphic data covering most of the important areas of calcareous sediment over the whole world ocean. The oxygen isotopic composition of foraminifera from cores of Late Pleistocene sediment varies in a similar manner in nearly all areas; the variations reflect changes in the oxygen isotopic composition of the ocean. The oceans are mixed in about 1 ka so that ocean isotopic changes, resulting from fluctuations in the quantity of ice stored on the continents, must have occurred almost synchronously in all regions. Thus the oxygen isotope record provides an excellent means of stratigraphic correlation. Cores accumulated at rates of over about 5 cm/ka provide records of oxygen isotopic composition change that are almost unaffected by post-depositional mixing of the sediment. Thus they preserve a detailed record of the advance and retreat of the ice masses in the northern hemisphere, and provide a unique source of information for the study of ice-sheet dynamics.

The relationship between vegetation and modern pollen assemblages on Mount Paggeo (NE Greece)

In this study, we investigated the relationship between vegetation and modern-pollen rain along the elevational gradient of Mount Paggeo. We apply multivariate data analysis to assess the relationship between vegetation and modern-pollen rain and quantify the representativeness of forest zones. This study represents the first statistical analysis of pollen-vegetation relationship along an elevational gradient in Greece. Hence, this paper improves confidence in interpretation of palynological records from north-eastern Greece and may refine past climate reconstructions for a more accurate comparison of data and modelling. Numerical classification and ordination were performed on pollen data to assess differences among plant communities that beech (Fagus sylvatica) dominates or co-dominates. The results show a strong relationship between altitude, arboreal cover, human impact and variations in pollen and nonpollen palynomorph taxa percentages.

"Lancea", Lusitanian Word, and the "Lancienses" Ethnogenesis

Analysis of the word lancea, of Hispanic origin after Varro, and of place names, people´s names and personal names derived from it. It confirms that the spear was the most important weapon in the Bronze Age, belonging to the iuventus and used as heroic and divine symbol. This analysis confirms also the personality of the Lusitanians, a people related to the Celts but with more archaic archaeological, linguistic and cultural characteristics originated in the tradition of the Atlantic Bronze in the II millennium BC. It is also relevant to better know the organisation of Broze and Iron Age societies and the origin of Indo-Europeans peoples in Western Europe and of pre-Roman peoples of Iberia.

La exploración del litoral atlántico norteafricano según el periplo de Hannón de Cartago

El periplo de Hannón, frente a las propuestas que lo interpretan como una obra literaria, creemos que recoge un periplo auténtico, que sólo alcanzó cabo Juby y algunas de las Islas Canarias. Las refundaciones cartaginesas fueron todas en la Mauretania fértil, en los 7 primeros días de la expedición. Desde el islote de Kérne, en la expedición primó una primera exploración de evaluación, indicativo de que se trataba de apenas 2 o 3 barcos, con una tripulación limitada, que evitaban enfrentamientos con la población local. Los intérpretes Lixítai parecen conocer todos los puntos explorados, el río Chrétes, los etíopes del Alto Atlas costero, el gran golfo caluroso que finalizaba en el Hespérou Kéras, el volcán Theôn Óchema, o las gentes salvajes que denominaban Goríllai. Probablemente la mayor sorpresa fuese encontrar un volcán activo, emitiendo lava, que pudo ser la razón última para redactar este periplo. La falta de agua, alimentos y caza como razón para finalizar la expedición exploratoria sólo es comprensible en un trayecto corto que alcanzó hasta el inicio del desierto del Sahara. Otro tanto sucede con la ausencia de ríos importantes al Sur del río Chrétes, una clara prueba de que no se alcanzaron latitudes ecuatoriales y que los barcos se fueron alejando de la costa norteafricana.

Quintus Curtius before his sources: the episode of Alexander and the Scythians on the Tanais

Quintus Curtius found in his sources a speech where a Scythian censured Alexander, followed by the King’s reply. Curtius drastically abridged this second discourse in order to highlight the criticism of the Macedonian. The Scythian’s words have a striking rhetorical language and some allusions taken from Greek literature, in addition to possible indirect references to Caligula. Curtius declares that he follows his source word-for-word aiming to justify these inconsistencies, but also trying to hide the manipulations he has done to achieve his own narrative purposes.

Microstructure and hardness characterisation of laser coatings produced with a mixture of AISI 420 stainless steel and Fe-C-Cr-Nb-B-Mo steel alloy powders

Fe-C-Cr-Nb-B-Mo alloy powder and AISI 420 SS powder are deposited using laser cladding to increase the hardness for wear resistant applications. Mixtures from 0 to 100 wt.% were evaluated to understand the effect on the elemental composition, microstructure, phases, and microhardness. The mixture of carbon, boron and niobium in the Fe-C-Cr-Nb-B-Mo alloy powder introduces complex carbides into a Fe-based matrix of AISI 420 SS which increases its hardness. Hardness increased linearly with increasing Fe-C-Cr-Nb-B-Mo alloy, but substantial micro-cracking was observed in the clad layer at additions of 60 wt.% and above; related to a transition from a hypoeutectic alloy containing α-Fe/α' dendrites with an (Fe,Cr)2B and γ-Fe eutectic to primary and continuous carbo-borides M2B (where M represents Fe and Cr) and M23(B,C)6 carbides (where M represents Fe, Cr, Mo) with MC particles (where M represents Nb and Mo). The highest average hardness, for an alloy without micro-cracking, of 952 HV was observed in a 40 wt.% alloy. High stress abrasive scratch testing was conducted on all alloys at various loads (500, 1500, 2500 N). Alloy content was found to have a strong effect on the wear mode and the abrasive wear rate, and the presence of micro-cracks was detrimental to abrasive wear resistance.