Using the STARE double pulse system to obtain the mean velocity and velocity of long-lived irregularities

The STARE and SABRE auroral radars use double pulses to measure one value of the autocorrelation function (ACF) to obtain the Doppler velocity of the irregularities in the E-region auroral zone. If the pulse separation of each double pulse is τ, then the measured velocity tends towards the mean velocity V_DP as τ → 0, and towards the velocity of the long-lived irregularities V_LL as τ → ∞. A practical implementation using these results is presented, which allows measurement of these two physically important velocities from just four pulse spacings, rather than the 11 or 15 currently used to obtain the full velocity spectrum in the STARE and SABRE radars, and thus gains greater precision or better time resolution. The two line-of-sight velocities, V_DP and V_LL, are in general not equal, with V_LL greater in magnitude than V_DP (sometimes much greater). Comparison of V_DP and V_LL for the two STARE stations and one of the SABRE stations shows interesting differences, and a number of statistically significant features. V_LL probably measures the velocity of primary irregularities whenever these exist with the appropriate k vector. Both velocities ought to be measured routinely, and also for comparison with other techniques.     

The investigation of long-distance HF propagation on the basis of a chirp sounder

Experimental data on round-the-world HF radio signals near the terminator are given. The critical frequency of the ionospheric waveguide is found to be F_c ∼ 16–17 MHz. At frequencies F < F_c the group delay has a negative dispersion $\text{τ}\text{dot}{}_{\mathrm{<mtext>g</mtext>}}\text{= ∂τ/∂F ⋍ −100}$ μs/MHz and $\text{τ}\text{dot}{}_{\mathrm{<mtext>g</mtext>}}\text{⋍ 80}$ μs/MHz for frequencies f > f_c. Ray-tracing calculations are carried out. It is found that the low frequency branch of round-the-world signals (F < F_c) is formed mainly by waveguide modes and the high frequency branch (F > F_c) by 0 ricochet and hop modes.Experiments on waveguide modes escaping from the ionospheric channel due to field-aligned scattering by artificial ionospheric turbulence are carried out. The conditions for trapping of radio waves in the ionospheric waveguide are investigated. It is shown that if the gradient of the critical frequency F₀F2 is less than minus 2 × 10⁻² MHz/100 km radio wave trapping takes place in the ionospheric waveguide at frequencies exceeding by 1–2 MHz the maximum observed frequency of the hop mode. The frequency time characteristics of the mode and the geophysical conditions for the effective control of radio waves escaping from the waveguide are defined.     

Quantitative analysis of COH fluids synthesized at HP–HT conditions: an optimized methodology to measure volatiles in experimental capsules

The quantitative assessment of COH fluids is crucial in modeling geological processes. The composition of fluids, and in particular their H₂O/CO₂ ratio, can influence the melting temperatures, the location of hydration or carbonation reactions, and the solute transport capability in several rock systems. In the scientific literature, COH fluids speciation has been generally assumed on the basis of thermodynamic calculations using equations of state of simple H₂O–nonpolar gas systems (e.g., H₂O–CO₂–CH₄). Only few authors dealt with the experimental determination of high‐pressure COH fluid species at different conditions, using diverse experimental and analytical approaches (e.g., piston cylinder + capsule piercing + gas chromatography/mass spectrometry; cold seal + silica glass capsules + Raman). In this contribution, we present a new methodology for the synthesis and the analysis of COH fluids in experimental capsules, which allows the quantitative determination of volatiles in the fluid by means of a capsule‐piercing device connected to a quadrupole mass spectrometer. COH fluids are synthesized starting from oxalic acid dihydrate at P = amb and T = 250°C in single capsules heated in a furnace, and at P = 1 GPa and T = 800°C using a piston‐cylinder apparatus and the double‐capsule technique to control the redox conditions employing the rhenium–rhenium oxide oxygen buffer. A quantitative analysis of H₂O, CO₂, CH₄, CO, H₂, O₂, and N₂ along with associated statistical errors is obtained by linear regression of the m/z data of the sample and of standard gas mixtures of known composition. The estimated uncertainties are typically <1% for H₂O and CO₂, and <5% for CO. Our results suggest that the COH fluid speciation is preserved during and after quench, as the experimental data closely mimic the thermodynamic model both in terms of bulk composition and fluid speciation.     

Ion-neutral collisions and the equatorial electrojet

There are various theoretical models of ion-neutral collision and the resultant collision frequencies (v_in) differ significantly in their values. Also there is a range of uncertainty associated with each of the theoretical values of v_in. The effects of the differing theoretical values and the uncertainty in the v_in on the estimates of the equatorial electrojet (EEJ) current strength are examined numerically. It is found that the differences in various v_in-models affect the amplitude of the EEJ, but leave the peak altitude of the EEJ nearly unchanged. However, modification to v_in by the order of its uncertainty does change the peak altitude of the EEJ by at least 2km.     

Stable carbon and nitrogen isotope variations in tooth dentine serial sections from Wharram Percy

Here we report δ¹³C and δ¹⁵N measurements of serial sections of human deciduous and permanent tooth dentine from archaeological samples taken from the medieval village site of Wharram Percy, Yorkshire, UK. We found a pattern of enrichment, for both δ¹³C and δ¹⁵N, where the tooth crown was greater than the cervical part of the root, which in turn was greater than the apical portion of the root and the associated rib collagen values. This pattern reflects a decrease in the consumption of isotopically enriched breast milk and the introduction of less enriched weaning foods in the diet. The (mean±SD) difference between the deciduous second molar crowns and corresponding rib samples from the same individuals after 2 years of age was 1.2±0.4‰ for δ¹³C and 3.2±0.8‰ for δ¹⁵N. The δ¹⁵N values are as predicted, but as there were no C₄plants at Wharram Percy, this 1.2‰ enrichment in δ¹³C represents clear evidence of a carbon trophic level effect in collagen from breastfeeding infants. Carbon and nitrogen results also show that the infant diet among those who died in infancy did not differ from those who survived into childhood. This study demonstrates the promise of using dentine serial sections to study the temporal relationships of breastfeeding, weaning, and dietary patterns of single individuals.     

Opposing peace: English political pamphlets against the Treaty of Madrid in 1630

ABSTRACT

In November 1630 the Treaty of Madrid was signed between Philip IV, king of Spain, and Charles I, king of England. During the peace negotiations several pamphlets critical of the pro-Spanish policy of Charles I were printed in England. These publications contributed to the development of an increasing criticism of Charles I, by identifying his neutral European policy with pro-Spanish policies. The anti-Spanish and anti-Catholic rhetoric, which formed the basis of this criticism, was used to promote an aggressive foreign policy and consequently an active opposition to the king. The following pamphlets are discussed in this paper: Considerations T ouching a W arre with Spaine; The M erchandises of Popish P riests; The English Spanish Pilgrim; Further O bservations of the English Spanish Pilgrim; The P ractise of P rinces; The P resent E state of Spayne; and Three S everall T reatises C oncerning the T ruce.     

New light on early caprine herding strategies from isotope analysis: a case study from Neolithic Anatolia

The measurement of stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes of caprine bone collagen from the Neolithic sites of Çatalhöyük and Aşıklı Höyük in south-central Anatolia have allowed examination of exploitation and herding practices of sheep and goats. The isotope values from protodomestic caprines at Aşıklı Höyük suggests that these animals were consuming very similar foods to each other and were all confined to the same or similar environments with no access to C₄ plants. At Çatalhöyük, the results show how the caprine management strategy develops from the strategy seen at Aşıklı Höyük into a more varied practice at an early stage as the site grows with an increasing dietary contribution obtained from C₄ plants. No change in diet is isotopically discernible at Aşıklı Höyük. Interestingly, no distinction could be made between the diets of sheep and goats at either site. Therefore, such studies are a useful method of examining the development of early herding or management strategies of caprines in the Near East.     

"中国"与"天下"的重合——古代中国疆域形成的历史轨迹

“The Central Kingdom” is pregnant of political implications as well as of geographical and cultural significance. It was believed that whoever controlled Zhongguo (the Central Kingdom or China) would be the legitimate ruler over Tianxia (the realm under heaven or all under heaven). It was the contention for “the Central Kingdom” among the varieties of dynasties, notably those established by the Han-Chinese and the various ethnic groups in the northern borderland, that lead to the alternation of disintegration and unification of the territory. It was not until the Qing Dynasty that the unified “Central Kingdom” composed of a variety of ethnic groups turned into the ideal “realm under heaven” with “the Central Kingdom” at its core, which naturally put an end to the formation of territory in ancient China. Translated by Chen Dan from Zhongguo Bianjiang Shidi Yanjiu 中国边疆史地研究 (China’s Borderland History and Geography Studies), 2007, (3): 1–15     

Anomalous diurnal phase shifts of Omega VLF waves (10–14 kHz) on the east–west low latitude and transequatorial paths

The phase of the Omega HAIKU (Hawaii, U.S.A.) and REUNION (La Reunion) signals were measured at Inubo, Japan and onboard ship at Fremantle. Australia. Strong east–west non-reciprocities of the diurnal phase shift are obtained both on the low latitude and transequatorial paths, and it is found that the non-reciprocity on one path is in an opposite sense to the other. The diurnal phase shift, ϕ_DN for the west-to-east (WE) propagation is 7.8–8.7 µs Mm^–1 at 13.6 kHz on the transequatorial and mid-latitude paths, indicating no significant latitude dependence of the phase velocity in WE propagation. On the other hand, ϕ_DN for the east-to-west (EW) propagation greatly depends on the geomagnetic latitude; at 13.6 kHz ϕ_DN = 11.3µs Mm^–1 on the low latitude path and ϕ_DN = 50 µs Mm^–1 on the transequatorial path, which are 40% greater and 35% less than ϕ_DN in WE propagation, respectively. The east-west non-reciprocities of ϕ_DN on the low latitude and transequatorial paths are interpreted in terms of a single mode propagation in the conventional anisotropic waveguide model with β_D = 0.3 km^–1, β_N = 0.5 km^–1 and h_N–h_D = 12.5 km. In particular, the anomalously small ϕ_DN on the EW transequatorial path is explained as due to the high phase velocity of the night-time first-order mode in the equatorial region within ±12° geomagnetic latitude.     

Mozambican archaeology: past and present

After a brief survey of the development of archaeology in Mozambique, the results of the archaeological survey programme of 1976–1983 are summarized by region. Work currently in progress is evaluated in the light of archaeological and national priorities and the paper concludes with a discussion of the theoretical approach best suited to Mozambican conditions.

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Résumé Suivant une brève étude de l'avancement de l'archéologie dans le Mozambique, les résultats du programme de reconnaissances archéologiques de 1976–1983 sont résumés par région. Les travaux actuellement en cours sont evalués à la lumière des priorités nationales et archéologiques et l'article se conclut avec une discussion sur la meilleure approche théorique convenant aux conditions actuelles.

     

Isenya: état des recherches sur un nouveau site acheuléen d'Afrique orientale

Résumé Isenya est le premier site acheuléen fouillé sur les hauts plateaux du Kenya. Sa richesse en vestiges lithiques et fauniques en fait dès maintenant un gisement important pour la connaissance des hominidés du Pléistocène moyen. Isenya est inclus dans un contexte sédimentaire fluviatile, indiquant que les hommes préhistoriques se sont installés sur une barre sableuse, le long d'une rivière qui était alors peut-être pérenne. La convergence des informations géologiques et archéologiques permet d'expliquer la mise en place des vestiges, la positionin situ de plusieurs niveaux d'occupation superposés, le faible degré de perturbation qu'ils ont subi, et l'origine essentiellement anthropique des associations os/pierres. L'industrie lithique est caractérisée par une grande abondance de bifaces et de hachereaux dont les proportions varient dans le temps. Une première analyse de l'ensemble apporte d'ores et déjà des indications sur les comportements techniques: les chaînes opératoires sont décryptées, depuis l'acquisition des matériaux jusqu'à l'obtention des outils. La faune associée à cet outillage est dominée par des animaux de savane ouverte (Alcelaphini etAntilopini). Son étude détaillée mettra en évidence les stratégies d'acquisition du gibier et son mode de consommation. Attirés, entre autres raisons, par la proximité de l'eau et des affleurements de phonolite, source principale de matière première pour l'outillage, les hominidés ont occupé cet enfroit de façon répétée dans un court laps de temps, selon une périodicité à rapprocher sans doute des comportements de subsistance.

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Isenya is the first Acheulian site excavated in the Eastern Highlands of Kenya. Very rich lithic and faunal remains in a fluviatile sedimentary context indicate hominid activity on a sandy bar next to a river, which was perhaps perennial. Microstratigraphy and archaeological data permit reconstruction of the processes by which the remains were deposited. Severalin situ occupation layers show only a slight degree of perturbation. The bone assemblage is of anthropic origin, and the lithic industry is characterized by an abundance of bifacial pieces, level VI being particularly rich in cleavers. From the analysis of the lithic industry we can obtain some idea of hominid technological behaviour, most notably the operational chains of tool production from the procurement of raw materials to the knapping sequences. The fauna associated with the lithic materials is dominated by animals of the open savanna (Alcelaphini andAntilopini); and its detailed study will allow us to specify the strategies used in the procurement of game and its subsequent consumption. Without doubt, the reasons for hominid occupation at this particular site will be impossible to explain fully. However, choice of this location, where evidence for several different activities has been uncovered, should be considered in terms of the proximity both of water and of outcrops of phonolite, the principal raw material for tool-making. Repeated occupation by hominids over a short time may, perhaps, correspond to the periodicity of their subsistence behaviour.

     

Fire and its roles in early hominid lifeways

Discovery of the uses and later the invention of fire-making are fundamental to humanity. Following reports over the last decade of traces of fire found on Lower Pleistocene archaeological sites in eastern Africa, the dating of the control of fire by hominids has become a controversial issue. In this paper we critically review the contexts and, in the light of a battery of archaeometric techniques, the nature of reported instances of fire from Koobi Fora and Chesowanja in Kenya, and from Gadeb and the Middle Awash in Ethiopia. We conclude with a discussion of the roles fire may have played in the lifeways of early Pleistocene savanna-living hominids.

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Résumé La découverte des usages du feu et ensuite de sa préparation est fondamentale pour l'humanité. Suite à des rapports au cours de la dernière décennie signalant des traces de feu relevées dans des sites archéologiques du Pléistocène inférieur dans l'est de l'Afrique, la datation du contrôle du feu par les hominiens est devenu une source de controverse. Dans cet article, nous révisons d'un oeil critique les contextes et la nature des cas de feu signalés à Koobi Fora et à Chesowanja au Kenya, et à Gadeb et dans l'Awash moyen en Éthiopie, à la lumière d'une suite de techniques archéometriques. Suit en conclusion une discussion sur les rôles qu'aurait pu jouer le feu dans les modes de vie des hominiens vivant dans les savannes du Pléistocène inférieur.

     

Book reviews

Books reviewed: Robert O. Keohane, Power and governance in a partially globalized world Michael Cox, Tim Dunne and Ken Booth, Empires, systems and states: great transformations in international politics Edward Keene, Beyond the anarchical society: Grotius, colonialism and order in world politics Antonio Franceschet, Kant and liberal internationalism: sovereignty, justice and international reform Bruno Coppieters and Nick Fotion, Moral constraints on war: principles and cases J. L. Holzgrefe and Robert O. Keohane, Humanitarian intervention: ethical, legal and political dilemmas Martha Minow, Breaking the cycles of hatred: memory, law, and repair Stephen Zunes, Tinderbox: US Middle East policy and the roots of terrorism Douglas Little, American orientalism: the United States and the Middle East since 1945 Princeton N. Lyman, Partner to history: the US role in South Africa's transition to democracy Gwyn Prins, The heart of war: on power, conflict and obligation in the twenty‐first century Barnett R. Rubin, Blood on the doorstep Philip Windsor. Edited by Mats Berdal and Spyros Economides, Strategic thinking: an introduction and farewell Colin S. Gray, Strategy for chaos: revolutions in military affairs and the evidence of history Stephen John Stedman, Donald Rothchild and Elizabeth M Cousens, Ending civil wars: the implementation of peace agreements Diana Francis, People, peace and power: conflict transformation in action Yonah Alexander, Combating terrorism: strategies of ten countries Alan Dershowitz, Why terrorism works: understanding the threat, responding to the challenge Caleb Carr, The lessons of terror: a history of warfare against civilians—why it has always failed, and why it will fail again Robert Mandel, Armies without states: the privatization of security Dana H. Allin, NATO's Balkan interventions Jane Chanaa, Security sector reform: issues, challenges and prospects Noam Chomsky, Power and terror: post 9–11 talks and interviews Roger Scruton, The West and the rest: globalization and the terrorist threat Philippe Legrain, Open world: the truth about globalisation Gerrie Ter Haar and James Busuttil, The freedom to do God's will: religious fundamentalism and social change Heather Rae, State identities and the homogenisation of peoples Roger Tooze and Christopher May, Authority and markets: Susan Strange's writings on international political economy M. J. Manohar Rao and Raj Nallari, Macroeconomic stabilization and adjustment Rhys Jenkins, Ruth Pearson and Gill Seyfang, Corporate responsibility and labour rights: codes of conduct in the global economy Jon Burchell, The evolution of Green politics: development and change within European Green parties Charles O. Holliday, Stephan Schmidheiny and Philip Watts, Walking the talk: the business case for sustainable development William Stueck, Rethinking the Korean War: a new diplomatic and strategic history Jonathan Pearson, Sir Anthony Eden and the Suez crisis: reluctant gamble Nigel J. Ashton, Kennedy, Macmillan and the Cold War: the irony of interdependence Elena A. Iankova, Eastern European capitalism in the making Stephanie Schwandner‐Sievers and Bernd J. Fischer, Albanian identities: myth and history Vadim Volkov, Violent entrepreneurs: the use of force in the making of Russian capitalism Lilia Shevtsova, Putin's Russia George W. Breslauer, Gorbachev and Yeltsin as leaders Madawi Al‐Rasheed, A history of Saudi Arabia Lyn Schumaker, Africanizing anthropology: fieldwork, networks, and the making of cultural knowledge in Central Africa Jamie Frueh, Political identity and social change: the remaking of the South African social order state Su Dongwei, Chinese stock markets: a research handbook Andrei Lankov, From Stalin to Kim Il Sung: the formation of North Korea 1945–60 Evan Gottesman, Cambodia after the Khmer Rouge: inside the politics of nation building Bob Woodward, Bush at war Richard Crockatt, America embattled: September 11, anti‐Americanism and the global order Karen Kampwirth, Women and guerrilla movements: Nicaragua, El Salvador, Chiapas, Cuba Ilja A. Luciak, After the revolution: gender and democracy in El Salvador, Nicaragua and Guatemala Sue Branford and Jan Rocha, Cutting the wire: the story of the landless movement in Brazil     

Poteries anciennes décorées à la roulette dans la Région des Grands Lacs

Résumé L'article propose une classification générale de la poterie ancienne décorée à la roulette, dans la Région des Grands Lacs et en Afrique de l'Est. Un premier groupe de poterie, appelé ici W, caractérisé principalement par la roulette torsadée, est produit vraisemblablement dèsca 800 AD; cette poterie pourrait avoir été diffusée de la région Est vers la zone interlacustre par le sud du Lac Victoria. L'hypothèse que le groupe W est associé à des populations de langues sud-nilotiques permet de reconsidérer les débuts du Deuxième Age du fer en Afrique interlacustre. Cet article suggère l'installation de groupes de pasteurs sud-nilotes dans la zone interlacustre; leurs rapports avec les autochtones sont examinés, en particulier le cas du Rwanda.Le groupe X (roulette nouée) apparaît en Ouganda dans les premiers siècles du second millénaire, suivi du groupe Y (roulette torsadée fine); à partir de 1500 AD, ils remplacent le groupe W dans la région interlacustre. Dans cet ensemble céramique, que l'on sait associé à des groupes de langues ouest-nilotiques venus du nord, une distinction est suggérée entre trois styles régionaux, qui sont mis en relation avec l'histoire des migrations de leurs producteurs.

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This article offers a general classification of the ancient roulette-decorated pottery from the Great Lakes Region and from East Africa. A first pottery group, here named W, mainly characterised by twisted string roulette, appears as early asca 800 AD; this pottery might have been introduced to the interlacustrine area from the east and south of Lake Victoria. The hypothesis that the W group was associated with speakers of Southern-Nilotic languages is relevant to our view of the beginning of the Late Iron Age in interlacustrine Africa. This article suggests the establishment of pastoralist groups of Southern-Nilotic speakers in the interlacustrine zone and also examines their contacts with local populations, giving special attention to Rwanda.The X group (knotted string roulette) appears in Uganda in the first centuries of the second millennium, followed by the Y group (thin twisted string roulette). Fromca 1500 AD these groups replaced the W group in the interlacustrine area. In these last groups, which are associated with Western-Nilotes coming from the north, a distinction is made between three regional styles which are further correlated with the history of their makers.

     

African metallurgy in the Atlantic world

This paper examines the history of African metallurgy in the era of Atlantic trade. It reports on excavations at the John Reeder foundry site in St Thomas, Jamaica. The transfer of African technologies to the Caribbean reveals the plantation economy's dependence on African technical expertise, not merely slave labour. The comprehensive focus on the Atlantic world also informs archaeological investigations of African-European interaction in West Central Africa. The complexity of Atlantic technological history is characterized by a diverse range of dynamic interactions, rather than the inevitable decline of Africanderived systems. Only by identifying processes as well as products of African technological interaction will it be possible fully to reconstruct the forging of the African past.

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Résumé Cet article examine l'histoire de la métallurgie africaine à l'ère du commerce atlantique. Il rend compte des excavations au site de la fonderie John Reeder, à St Thomas, en Jamaïque. Le transfert des technologies africaines aux Antilles révèle à quel point l'économie de plantation dépendait de l'expertise technique africaine, et pas seulement de l'esclavage. L'accent placé sur le monde atlantique inspire aussi les recherches archéologiques sur l'interaction afro-européenne à l'ouest de l'Afrique centrale. La complexité de l'histoire technologique atlantique est caractérisée par une gamme diverse d'interactions dynamiques, plutôt que par l'inévitable déclin des systèmes africains dérivés. Ce n'est qu'en identifiant les processus aussi bien que les produits de l'interaction technologique africaine qu'il sera possible de reconstruire complètement l'élaboration du passé africain.

     

Modelling the penetration of thundercloud electric fields into the ionosphere

In a previous paper, we considered the penetration of DC thundercloud electric fields E into the ionosphere and also into the region between the ionosphere and the ground (Velinov and Tonev, 1994). In the present paper, we extend the analysis by making a more precise approximation of the electric conductivity profiles by 5–10 piecewise exponential functions of altitude instead of the two functions used up to now. This allows a much more realistic representation of the atmospheric conductivity profile. Besides, Maxwell's equations are solved for more general boundary conditions, taking into account that the electrosphere is not a perfect conductor. This leads to the appearance not only of the transverse E_r (as had been assumed until now), but also of the geomagnetic field-aligned E_z component of the penetrating thundercloud electric fields. The computations show that both E_r and E_z cause significant variations of the electron density profiles N(z) in the ionosphere.     

Ceramic Seriation, Sites Chronology, and Old Oyo Factor in Northcentral Yorubaland, Nigeria

This study is an attempt to provide a chronological seriation of pottery from Igbomina in northcentral Yorubaland. The ceramic sequence is developed using multivariate statistical analysis. From the K-means cluster analysis, ceramic collections that are roughly contemporaneous were grouped together; next the collections were seriated with multidimensional scaling to reveal whether they form a pattern that may be chronologically significant. Evaluation of the results of the pottery analysis from the Igbomina sites was based on the chronological division of Old Oyo pottery as well as on radiocarbon dating of associated material from excavated sites in the region. Pottery types from Old Oyo became known in Igbomina probably as early as the thirteenth century AD, and continued to occur in some areas until the late eighteenth century. The presence of Oyo pottery in Igbomina has important implications for the understanding of Oyo's relations with the northern Yoruba group and the frontier position of Igbomina during the Old Oyo Empire.Cette étude cherche à fournir une sériation chronologique de la céramique provenant de Igbomina situé dans la partie centrale du nord de Yorubaland. La séquene de céramique a été élaborée en utilisant une analyse statistique multidimensionnelle. Les collections de céramique plus ou moins contemporaines ont été groupées en se servant de la moyenne du facteur K de la classification ascendante hiérarchique, elles ont ensuite été ordonnées au moyen d'une analyse des proximités pour voir si elles formaient un schéma chronologique significatif. L'évaluation des résultats de l'analyse céramique des sites Iglomina est fondée sur les divisions chronologiques de la céramique Oyo ancienne ainsi que sur des dates radiocarbones obtenues sur du matériel en association provenant de sites fouillés dans la région. Les types de céramique de l'Oyo ancien sont probablement arrivés à Igbomina dès le 13ème siècle et ont continué à apparaître dans certains endroits jusqu'à la fin du 18ème siècle. La présence de la céramique Oyo à Igbomina comporte des implications importantes pour nos connaissances sur les relations des Oyo avec les groupes Yoruba du nord et sur la position de la frontière de Igbomina pendant l'empire Oyo ancien.     

Culture contact,continuity, and change on the Gold Coast,AD 1400–1900

This article briefly examines the consequences of the European presence on the Gold Coast, focusing on archaeological, ethnographic, and historical data from the African settlement of Elmina, Ghana. Documentary sources indicate that there was extensive change in sociopolitical institutions, economic relations, and other aspects of Gold Coast society in the centuries following the advent of European trade in the late fifteenth century. Archaeological survey and excavation of some 30 structures at Elmina similarly indicates a great deal of change in construction technology and material culture during the post-European contact period. However, examination of artefact patterning and associations indicates that in certain respects there was little change in terms of people's shared world view and belief systems. This picture can be contrasted with data from sites in other areas which may have experienced a great deal of culture change during the post-European contact period.

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Résumé Cet article examine brièvement les conséquences de la présence européenne sur la Côte de l'Or, se penchant plus particulièrement sur les données archéologiques, ethnographiques et historiques du site d'Elmina au Ghana. Les sources documentaries indiquent qu'un changement de grande envergure affectant les institutions socio-politiques, les relations économiques et d'autres aspects de la société de la Côte de l'Or pris place durant les siècles suivant l'arrivée du commerce européen à la fin du quinzième siècle. Un survey archéologique et les fouilles d'environ 30 structures à Elmina, indiquent aussi qu'un changement étendu des techniques de construction et de la culture matérielle s'effectue après la période de contact européen. Toutefois, l'étude de la distribution et des associations des objets, indique que le système de croyance et l'idée du monde partagée par cette société furent peu affectés.Cette image peut être comparée avec les données obtenues sur d'autres sites ayant fait l'expérience d'un changement culturel important pendant la période postérieure aux contacts européens.

     

Early Neolithic diet and animal husbandry: stable isotope evidence from three Linearbandkeramik (LBK) sites in Central Germany

The first appearance of the Neolithic Linearbandkeramik (LBK) in Central Germany occurred during the 6th millennium BC. However, though LBK sites are abundant in the German loess areas, there are only a few studies that reconstruct the diet of these first farmers using biochemical methods. Here we present the largest study undertaken to date on LBK material using stable isotope analysis of carbon and nitrogen to reconstruct human diet and animal husbandry strategies. We analyzed the bone collagen of 97 human individuals and 45 associated animals from the sites of Derenburg, Halberstadt and Karsdorf in the Middle Elbe–Saale region of Central Germany. Mean adult human values are ?19.9 ± 0.4‰ for δ¹³C and 8.7 ± 0.8‰ for δ¹⁵N. The δ¹³C values are typical for terrestrial, temperate European regions, whereas the δ¹⁵N values fall within an expected range for farming societies with a mixed diet consisting of products from domestic animals and plants. The consumption of unfermented dairy products is unlikely as there is direct palaeogenetic evidence of lactose intolerance available for one of the sites. There are no clear indications for dietary differences in sex. Young children under three years of age are enriched in δ¹⁵N due to breastfeeding indicating that weaning likely occurred around the age of three years. The fauna exhibit mean δ¹³C values of ?20.9 ± 0.8‰ and mean δ¹⁵N values of 7.0 ± 0.9‰ respectively. Variation in the δ¹³C and δ¹⁵N in the domestic animals is probably caused by different livestock managements.     

A semi-analytic method for studying plasma properties near the F2-peak of the low latitude ionosphere

We have derived analytic expressions connecting the three plasma parameters namely hm, the height of the F2-peak; Nm, the peak density and Ym, the radius of curvature of the vertical profile at hm, which help us to explain certain features of the plasma distribution in the ionosphere. Although both Nm and TEC (total electron content) exhibit the equatorial anomaly in response to the fountain effect, TEC does not show a noon-time bite-out whereas Nm does. Moreover, we predict that the response of TEC towards the fountain effect is weaker than that of Nm, which we substantiate with simultaneous observations of Nm and TEC in the Indian zone. Thus we have shown that even one-dimensional analysis can explain those effects which are generally thought of as two-dimensional phenomena.