Radiative perturbation due to the eruption of El Chichón: Effects on ozone

The ozone depletion over the Antarctic region is now attributed to processes involving heterogeneous chemistry on polar stratospheric clouds. Similar mechanisms are probably working also in the Northern hemisphere high latitudes [Douglass and Stolarski (1989) Geophys. Res. Lett. 16, 131] and may be important in explaining the secular trend of ozone in the last twenty years above 50° North [Pitari and Visconti (1991) J. geophys. Res. 96, 10,931]. Hofmann and Solomon [(1989) J. geophys. Res. 94, 5029] have shown that the local observed decrease in the ozone amount following the eruption of El Chichón could be explained in terms of heterogeneous chemistry on the volcanic aerosol surface. In this paper we use a two dimensional model to study the effects on ozone introduced by the El Chichón aerosols through a perturbation in the radiation field; both the temperature and the photolysis rates are affected. We show that up to half of the observed decrease may be attributed to radiative effects at mid latitudes.     

Characterisation of obsidian subsource variability at El Paredón,Mexico

Portable X-ray fluorescence (pXRF) geochemical analysis on obsidian from five Formative period (1200 BCE to AC 100) sites from Tlaxcala, Mexico, has revealed that most of the material had similar values to those found in the closest obsidian source, named El Paredón, Puebla. Nevertheless, initial analyses did not resolve whether these materials came from the same caldera or from a specific obsidian deposit. Here we present a methodology that allows the identification of obsidian subsources. The results reveal that Tlaxcalan populations took advantage of a specific obsidian deposit called Tres Cabezas, Puebla, providing valuable new data to identify associated regional exchange networks.     

El rey que fue animal: sobre la invención del otro en Calderón,Dostoievski y Coetzee

The aim of this article carries a comparison between Calderón and Dostoevsky, their semblances and differences. First, I study a relationship toward otherness which is, in both cases, problematic and modern. Departing from Segismundo's complaints when he is imprisoned (saying that he is living a life “worse than animals live”) I analyze two kinds of misunderstandings: a white blindness that respects the Other's difference, and the evil inside its unconcealment. Finally, I discuss Coetzee's Dostoevsky (in The Master of Petersburg) in relation to some of the thesis outlined previously: the necessity of respect when dealing with the space of the other, either in its human form or in a non-human presentation.     

Early Magdalenian Variability: New Evidence from El Mirón Cave,Cantabria, Spain

Abstract

Sediments in and in the area of archaeological sites provide an invaluable source of information on palaeoenvironments and past human activities. Examination of the composition, texture, and structure of sediments has been used successfully in many sites of different kinds to reconstruct palaeoclimates. Sediment analysis has also been used in recognizing activity areas and in interpreting the processes involved in the formation and destruction of archaeological sites. In addition, sediment analysis can be applied to elucidate the relationship between changes in subsistence-settlement systems and environmental change. The methods of sediment analysis in archaeology includes, in addition to the standard sedimentological methods, special microarchaeological analyses.     

Estimating the Number of Combatants during the Mixtón War in the Peñol de Nochistlán

Abstract

The objective of this article is to determine the number of combatants in the Mixtón War (1541–42), one of the most important military confrontations of the early years of the vice-royalty in Western Mexico, by analysing the Peñol de Nochistlán. To this end, information provided by historians has been compared with the population estimates established from the density of settlements known from archaeological evidence in order to define the area occupied by the armies involved in the conflict. This exercise resulted in a shifting array of spaces that could have been used by the combatants during confrontations. However, it will enable more intense archaeological prospecting in the area around the site of El Tuiche — the place identified as the Peñol of Nochistlán — revealing new evidence of the events that occurred on this battlefield.     

‘In the very eye of the storm’: India,the UN,and the Lebanon crisis of 1958

This paper effectively provides the view from New Delhi of the crisis in Lebanon in 1958, UN intervention in the conflict, and subsequent peacekeeping in the region. The account uses archival material from the National Archives of India, the Nehru Memorial Museum and Library, New Delhi, the UNARMS, the National Archives, UK, and published primary material. Most significantly, the paper revisits the memoirs of Ambassador Rajeshwar Dayal (the UN Secretary General’s Special Representative) who was seconded from the Indian Foreign Service for the special purpose of UN arbitration in the Lebanon Crisis. Dayal played a pivotal role in defining India’s position in the crisis, and through Indian contributions to mediation and peacekeeping, in the UN. Furthermore, given India’s relationships with many other non-aligned nations in the region, the paper takes a broader view of the narratives surrounding the crisis and eventual US intervention and victory from mainly Indian sources, thus contributing to the study of the short-lived crisis.     

The Historic Port of El Real de Salinas in Campeche, and the Role of Coastal Resources in the Emergence of Capitalism in Yucatán, México

The emergence of capitalism in the peninsula of Yucatán is generally presented as a process resulting from the capitalization of the agricultural sector and the export of products from its sugar, cotton, and henequén plantations in the nineteenth century. In addition to these products, the peninsula also had a dynamic coastal economy in which the harvesting of salt and the extraction of logwood (Haematoxylum campechianum), played a major role and contributed to the flow of goods to international markets. We present a preliminary archaeological survey and historical documentation of El Real de Salinas, a salt-producing port on the north coast of Campeche, which was also involved in the extraction of other coastal products and closely linked to the inland plantation system.

Electrical conductivities,ion densities and mobilities in the middle atmosphere over India—balloon measurements

Polar conductivities, ion densities and mobilities measured in three balloon experiments are reported here. Of these, two were made with self-aspirated and one with pumped Gerdien condensers. These measurements were carried out over the period 1985–1986. Both positive and negative ion data were obtained only in the first flight. Positive ions were not collected in the other two flights. The conductivity profiles obtained from the self-aspirated condensers showed fluctuations around the tropopause. These were not seen when the pumped condenser was used. Reduced mobilities of both positive and negative ions agree well with those reported by other experimenters. The ion density profile from the pumped condenser measurement showed a broad maximum around 15 km, as expected from theory. The values were less than what are obtained using available ion pair production rates and recombination coefficients.     

Ghana,India, and the Transnational Dynamics of the Congo Crisis at the United Nations, 1960–1

This article examines the role of Ghana and India at the United Nations during the Congo crisis from July 1960 to February 1961. The role of non-aligned countries both in the UN peacekeeping force, Opération des Nations Unies au Congo (ONUC), and in the negotiation of Congo policy was fundamental to the evolution of events. The article shows how Jawaharlal Nehru of India and Kwame Nkrumah of Ghana used the Non-Aligned Movement (NAM) and the Afro-Asian bloc to alter UN Congo policy. In leveraging their influence with in the General Assembly, the NAM was able to sustain the UN effort in the Congo and preserve the prestige of the organisation. In the process, NAM members realised the benefits and the limitations of non-aligned politics in the context of a violent, anti-colonial war. The crisis had the effect of rupturing the status quo at the UN and in the eight months under study here, it is argued that the actions of the NAM within the UN helped to activate the agency of the organisation in pursuit of neutralist principles. The Congo crisis served as the turning point in the decolonisation drama and NAM's influence over UN Congo policy represented a dynamic form of anti-colonial internationalism.     

Geometry,Construction and Structural Analysis of the Crossed-Arch Vault of the Chapel of Villaviciosa,in the Mosque of Córdoba

The vault of Villaviciosa is one of the oldest existing examples of a true ribbed vault, and is the first of the crossed-arch type. Although its perfection suggests earlier trials, none has been found so far. It predates the oldest Romanesque ribbed vaults by more than a century. Notwithstanding its importance, no construction and structural study has ever been done; neither has an accurate survey been published. The purpose of this article is to fill this gap in the history of vault construction. A detailed survey has been made, providing the first accurate drawings of the vault. A close inspection of the extrados, completed with a visual inspection of interior damages, has allowed ascertaining the main construction features. With the geometry and the material data a structural analysis has been carried out. This analysis explains the fundamental structural behavior of the vault and throws new light into some historical issues; for example, it leads to discarding the widespread belief that the ribs are decorative: they are supporting the weight of the vault.     

Native Californians at the Presidio of San Francisco: Analysis of Lithic Specimens from El Polín Spring

Relatively few archaeological studies have examined the experiences of native people at Spanish colonial military installations. A small flaked lithic assemblage at the Presidio of San Francisco provides insight into the lives and labor of Native Californians there. Technically proficient knappers, making do with poor-quality, locally available material, engaged in freehand core reduction and produced non-symmetrical, bifacially flaked tools through percussion production. These tools were most likely used for cutting during specific tasks. The analysis reveals how Native Californians in colonial institutions maintained flintknapping traditions in social spaces that were likely shared by native people and colonists.