Holocene glacial history of Antarctica and the sub-Antarctic islands

A history of Holocene glaciation in the Antarctic and sub-Antarctic affords insight into questions concerning present and future ice-sheet and mountain-glacier behavior and global climate and sea-level change. Existing records permit broad correlation of Holocene ice fluctuations within the region. In several areas, ice extent was less than at present in mid-Holocene time. An important exception to this is the West Antarctic Ice Sheet, which has undergone continued recession throughout the Holocene, probably in response to internal dynamics. The first Neoglacial ice advances occurred at 5.0 ka, although some sites (e.g., western Ross Sea) lack firm evidence for glacial expansion at that time. Glaciers in all areas underwent renewed growth in the past millennium, and most have subsequently undergone recession in the past 50 years, ranging from near-catastrophic in parts of the Antarctic Peninsula to minor in the western Ross Sea region and sections of East Antarctica. This magnitude difference likely reflects the much greater warming that is taking place in the Antarctic Peninsula region today as compared to East Antarctica.     

The Class 0 source Barnard 1c

We present our most recent results from an ongoing study of the Class 0 source Barnard 1c in Perseus. This source is of particular interest because it exhibits evidence of strong alignment of grains all the way to the core’s centre, which is contrary to all other low-mass protostellar cores observed to date. Our goal is to clarify the source of poor alignment in other sources by identifying the source of strong alignment in B1c. A central cavity has been identified in N₂H⁺ emission; its anticorrelation with C¹⁸O emission suggests that heating in the centre has released CO from grain mantles, in turn destroying N₂H⁺. We present sensitivity-limited, high spatial resolution polarimetry data from the SubMillimeter Array and discuss the potential implications of these data.     

Constructing Community Through Maps? Power and Praxis in Community Mapping*

Despite the growing practice of community mapping, empirical research remains limited. Extant studies have focused primarily on “counter‐maps” and indigenous maps, leaving many locally produced maps and their authors' perspectives unexplored. This article identifies the mapping process as critical to the definition and understanding of community mapping. It links critical cartography literature to goals of community‐mapping practitioners through themes of inclusion, transparency, and empowerment. The discussion highlights the social construction and practice of “community,” the relationship between maps and power, the definitional difficulties associated with community mapping, and the figurative and literal boundaries that constrain community cartography. Finally, it points to areas for further research and exploration.     

A new formation process for calcic pendants from Pahranagat Valley, Nevada, USA, and implication for dating Quaternary landforms

It has been assumed that soil pendants form in a similar manner as stalactites, in which innermost laminae are the oldest and outer laminae are the youngest. This study presents a new interpretation for soil pendant development. Pahranagat Valley, Nevada, pendants contain features indicating continued precipitation through time at the clast–pendant contact, implying that the oldest deposits are not always found at the pendant–clast contact, as other studies have assumed. These features include a void at the clast–pendant contact where minerals such as calcium carbonate, silica, and/or fibrous silicate clays precipitate. In addition, fragments of the parent clast and detrital grains are incorporated into the pendant and are displaced and/or dissolved and result in the formation of sepiolite. This study indicates that pendants are complex, open systems that during and after their formation undergo chemical changes that complicate their usefulness for dating and paleoenvironmental analyses.     

Singaporeans in China: transnational women elites and the negotiation of gendered identities

The burgeoning literature on transnationalism involving skilled migrants--based largely on the view from the developed world--have generally paid little heed to “elite” women and the reproductive sphere. We argue that women play many roles in elite transnational migration streams and must be given full consideration as part of the “transnational elite.” Attention is given to the way women--both “tied” and “lead” migrants--negotiate gendered identities as they participate in Singapore's regionalisation process, a state-driven initiative to extend the national economy by leveraging on growth in the region. Empirical material for the paper is mainly based on in-depth interviews with married women who were part of a larger project involving interviews with 150 Singaporeans who had lived, or were living, in China. In examining the movements through transnational space between Singapore and China, it is clear that patriarchal norms continue to shape women's understandings of their own identities vis--vis men's. Singapore women who move as accompanying spouses (the majority) find themselves giving up careers to focus on their domestic role in China (in the absence of access to “suitable” paid domestic service), and are not so much “deskilled” but “re-domesticated”. The exceptional few women who ventured into China as entrepreneurs experienced considerable strain holding together geographically separate spheres of productive and reproductive work across the transnational terrain. Both sets of “stories” alert us to the need to include “elite” women--whether accompanying spouses or independent entrepreneurs--in our understanding of “transnational elites.” This will contribute to the urgent task of ensuring that both productive and reproductive work are valorized in equal measure in conceptualizing transnationalism.     

Population Belongs on the Johannesburg Agenda

The forthcoming World Summit on Sustainable Development (WSSD) in Johannesburg (August 26-September 4, 2002) has been set by the United Nations to consider strategies toward sustainable development in all its dimensions. Hence, its mandate is broader than that of the Rio 1992 United Nations Conference on Environment and Development (UNCED). Population issues have so far been discussed in a separate series of World Population Conferences (Bucharest 1974, Mexico City 1984, Cairo 1994). With no new World Population Conference scheduled for 2004 and Johannesburg having a mandate that is stated to explicitly include social and economic aspects, population as a key component of sustainable development should figure prominently on the Johannesburg agenda. Yet, after the third of four preparatory meetings for Johannesburg (which ended in New York on April 5th), consideration of population is completely absent. The reasons for this are not entirely clear. We assume that they have to do with the fear of entering into political controversies over abortion. We are concerned that, despite its broader mandate, in most countries inputs to Johannesburg are being prepared mainly by environment ministries who have little experience in dealing with population questions. This revised version was published online in July 2006 with corrections to the Cover Date.     

THE HUMAN GEOGRAPHY OF SOUTHEAST ASIA: AN ANALYSIS OF POST-WAR DEVELOPMENTS

This paper reviews the directional shifts in human geographical research on Southeast Asia from 1945 to the present. It first begins with an overview of the identity of the region as conceived in various cultural traditions, such as the Greek, Arabic and Indian traditions. This is followed by an evaluation of regional geographies of Southeast Asia in the post-war period, highlighting the pre-eminence of the geostrategic definition of the region and the failure to come to grips with its rich cultural-historical identity. The paper then goes on to show that, arising from the changes in conceptual developments and methodologies in geography, the early regional emphasis then shifted to systematic concerns, with a movement away from ‘encyclopaedic’ to ‘adjectival’ geography (economic, urban, population, political, cultural and historical) and a greater emphasis on issues concerning national development. Since the 1980s, there have also been fewer regional works on Southeast Asia and though there are now many more indigenous geographers within the region, much of their research is based on their own national or provincial areas. However, this may shift again, given that rapid economic growth has now given the region prominence. Certainly, there is renewed multi-disciplinary interest in Southeast Asia.     

Polycyclic aromatic hydrocarbons in the Murchison meteorite

More than thirty polycyclic aromatic hydrocarbons, including nine heterocyclic aromatic compounds, have been identified in solvent extracts of the Murchison meteorite by gas chromatography-mass spectrometry using bonded-phase fused silica columns. Structural isomers of several alkylated aromatic hydrocarbons, including methylpyrene and methylphenanthrene were chromatographically separated, thus allowing calculations of the amount of alkyl substituted compounds in the solvent extracts. The ratio of odd-carbon number to even-carbon number was found to be approximately 0.1. Based on these data and literature data from model pyrolysis experiments, a temperature of 1000°C is suggested for the formation of polycyclic aromatic hydrocarbons in the solar nebula or premeteoritic body. The value of 1000°C is within the range of temperatures for the condensation of the nebular material from the initial high temperature phases to the lower temperature phases at which chemical and isotopic equilibria were frozen. A simple model for the abiotic synthesis of heterocyclic compounds from simple aliphatic precursors is also presented.