Competition and resource availability in an annual plant community dominated by an invasive species, Carrichtera annua (L. Aschers.), in South Australia

The last decade has seen spirited debates about how resource availability affect the intensity of competition. This paper examines the effect that a dominant introduced species, Carrichtera annua, has upon the winter annual community in the arid chenopod shrublands of South Australia. Manipulative field experiments were conducted to assess plant community response to changing below-ground resource levels and to the manipulation of the density of C. annua. Changes in the density of C. annua had little effect on the abundance of all other species in the guild. Nutrient addition produced an increase in the biomass of the most abundant native species, Crassula colorata. An analysis of the root distribution of the main species suggested that the areas of soil resource capture of C. annua and C. colorata are largely segregated. Our results suggest that intraspecific competition may be stronger than interspecific competition, controlling the species responses to increased resource availability. The results are consistent with a two-phase resource dynamics systems, with pulses of high resource availability triggering growth, followed by pulses of stress. Smaller plants were nutrient limited under natural field conditions, suggesting that stress experienced during long interpulse phases may override competitive effects after short pulse phases. The observed differences in root system structure will determine when plants of a different species are experiencing a pulse or an interpulse phase. We suggest that the limitations to plant recruitment and growth are the product of a complex interplay between the length and intensity of the pulse of resource availability, the duration and severity of the interpulse periods, and biological characters of the species.

An international perspective on sunken state vessels as underwater cultural heritage

On 2 November 2001, the General Assembly of the United Nations Scientific, Economic and Cultural Organisation (UNESCO) adopted the convention on the Protection of the Underwater Cultural Heritage. Among the many complex issues addressed in the convention is the legal status of sunken state-owned vessels, including warships. Prior to the adoption of this convention, no conventional or customary international law existed with regards to the question of abandonment of state-owned vessels or the application of the principle of sovereign immunity to sunken state vessels. While difficulties between coastal states and maritime and former colonial powers resulted in a regime that does not comprehensively address the issues, the convention does provide some guidance in this regard and may provide a basis for further development.

Low input tillage/cropping systems for limited resource areas

Agriculture in limited resource areas is characterized by small farms which an generally too small to adequately support the needs of an average farm family. The farming operation can be described as a low input cropping system with the main energy source being manual labor, draught animals and in some areas hand tractors. These farming systems are the most important contributor to the national economy of many developing countries. The role of tillage is similar in dryland agricultural systems in both the high input (HICS) and low input cropping systems (LICS), however, wet cultivation or puddling is unique to lowland rice-based systems in low input cropping systems. Evidence suggest that tillage may result in marginal increases in crop yield in the short term, however, in the longer term it may be neutral or give rise to yield decreases associated with soil structural degradation. On marginal soils, tillage may be required to prepare suitable seedbeds or to release adequate Nitrogen through mineralization, but in the longer term, however, tillage reduces soil organic matter content, increases soil erodibility and the emission of greenhouse gases. Tillage in low input cropping systems involves a very large proportion of the population and any changes: in current practices such as increased mechanization will have a large social impact such as increased unemployment and increasing feminization of poverty, as mechanization may actually reduce jobs for women. Rapid mechanization is likely to result in failures, but slower change, accompanied by measures to provide alternative rural employment, might be beneficial. Agriculture in limited resource areas must produce the food and fiber needs of their community, and its future depends on the development of sustainable tillage/cropping systems that are suitable for the soil and climatic conditions. These should be based on sound biophysical principles and meet the needs of and he acceptable to the farming communities. Some of the principle requirements for a sustainable system includes the maintenance of soil health, an increase in the rain water use efficiency of the system, increased use of fertilizer and the prevention of erosion. The maintenance of crop residues on the surface is paramount for meeting these requirements, and the competing use of crop residues must be met from other sources. These requirements can be met within a zonal tillage system combined with suitable agroforestry, which will reduce the need for crop residues. It is, however, essential that farmers participate in the development of any new technologies to ensure adoption of the new system. (C) 2001 Elsevier Science B.V. All rights reserved.

The over-production of US sports and the new International Division of Cultural Labor

This article focuses on how US professional sports utilize the New International Division of Cultural Labor to supplement an overly costly local labor pool and over-supplied local market. We argue that while the classic problem of over-production is slowly eroding the sealed-off nature of US culture, the forces of its hyper-protectionist capitalism continue to characterize sports, precluding equal exchange.

Centro de Inform??tica, Cidadania e Produ????o Cultural para Minorias: CIPRO

O Centro de Inform??tica, Cidadania e Produ????o Cultural Para Minorias (CIPRO) ?? um projeto articulado pela Delegacia Regional do Trabalho do Rio de Janeiro (DRT/RJ) e administrado conjuntamente com diversas Organiza????es N??o Governamentais, entre elas o Comit?? Pela Democratiza????o da Inform??tica (CDI), o Grupo Cultural Afro Reggae (comunidade de Vig??rio Geral), o Grupo Pela Vidda (portadores do HIV) dentre outras. O CIPRO oferece n??o s?? cursos de qualifica????o profissional, mas tamb??m uma infra-estrutura que permita aos alunos praticarem aquilo que aprenderam. Nossa clientela ?? de pessoas que procuram a DRT/RJ para receberem seu seguro desemprego. Tamb??m s??o atendidas pessoas discriminadas ou sem seguro desemprego. O projeto foi oficialmente lan??ado em 28/05/99. Apesar de n??o possuir quaisquer recursos financeiros, treinou em seu primeiro ano de atividade mais de 180 alunos em inform??tica, produ????o cultural e gest??o social. O CIPRO ?? um projeto social constru??do a partir do n??o paternalismo: instrutores s??o ex-alunos e coordenadores s??o ex-administradores, todos entendendo que sua inser????o no mercado de trabalho somente se dar?? a partir do seu esfor??o pessoal e de sua compet??ncia profissional