130 research outputs found
Estimates of the impacts of invasive alien plants on water flows in South Africa
The adverse impacts of alien plant invasions on water flows have been a prime motivation for South Africaâs Working for Water Programme. The approach used in this study builds on a previous national assessment in 1998 by incorporating factors that limit plant water-use, information from recent research and improved flow reduction models. The total reduction in flows is estimated to be 1 444 million m3·yrâ1 or 2.9% of the naturalised mean annual runoff (MAR), less than half of the 3 300 million m3·yrâ1 estimated in 1998. Two main factors account for this difference: (a) a decrease in the estimated unit-area flow reduction to 970 m3·haâ1·yrâ1 compared with 1 900 m3·haâ1·yrâ1 estimated in 1998, largely due to the new model being based on more representative reduction factors; and (b) the updated estimate of the condensed invaded area of 1.50 million ha (previously 1.76 million ha), although the taxa mapped for this assessment only accounted for 1.00 million of the 1.76 million ha reported in 1998. Reductions due to invasions in Lesotho are estimated to be about 161 million m3·yrâ1 and those in Swaziland about 193 million m3·yrâ1. The taxon with the greatest estimated impact was wattles (Acacia mearnsii, A. dealbata, A. decurrens) with 34.0% of the total reductions, followed by Pinus species (19.3%) and Eucalyptus species (15.8%). The revised estimate is considered on the low side largely because the extent and impacts of riparian invasions have been underestimated. If the current estimates that 4â6% of Acacia mearnsii, Eucalyptus, Populus and Salix invasions are riparian, are adjusted to a more representative 20%, 50%, 80% and 80%, respectively, the total reductions increase by nearly 70% to ~2 444 million m3·yrâ1. Producing these estimates involved a number of assumptions and extrapolations, and further research is needed to provide more robust estimates of the impacts.Keywords: plant water-use, flow reduction, mean annual runoff, riparian invasions, Working for Water Programm
Householdsâ responses to spousal job loss: âall changeâ or âcarry on as usualâ?
Economic theory suggests that when a primary earner within a couple loses their job, one potential response is for the secondary earner to seek additional paid work to bolster their household finances. The empirical quantitative evidence regarding any such âadded worker effectâ is mixed, and, to investigate why this might be, the article explores processes behind couplesâ responses to job loss. Drawing on in-depth qualitative interviews conducted with a purposive sample selected from the Understanding Society Innovation Panel, the analysis examines: (a) anticipation surrounding job loss and job search responses; (b) the extent to which couples adopt long- or short-term labour market perspectives; and (c) whether couples seek to preserve their established division of paid and unpaid labour or re-configure their joint labour supply. Findings indicate that the use of additional spousal labour is only one response among many alternatives and it is typically invoked in cases of serious financial hardship. </jats:p
Environmental horticulture for domestic and community gardensâAn integrated and applied research approach
Societal Impact Statement
Daunting global challenges of climate change and biodiversity loss may seem overwhelming. However, gardeners have a secret weaponâgardens, balconies, indoor planting, yards and allotments are mini-ecosystems that offer opportunities to counter perceptions of helplessness, inadequacy and resultant inaction by using those spaces to âDo what we can, with what we have, where we areâ. Minimising gardening âfootprintsâ to mitigate harmful impacts, whilst maximising gardening âhandprintsâ to enhance benefits, is readily achievable. With this in mind, the Royal Horticultural Society is leading research into environmental horticulture for gardens, and benefits for individual wellbeing.
Summary
This article presents an integrated and applied research approach to the unique and multi-disciplinary area of science referred to here as environmental horticulture. It does this by: (a) providing an institutional perspective (The Royal Horticultural Society) on a research approach for this particular area, emphasising why domestic and community gardens are important in the context of global environmental threats; (b) presenting four primary research focus areas and project examples; and (c) highlighting interdisciplinary linkages, future research needs, public engagement/knowledge sharing opportunities, and âGreen Skillsâ development in the area of environmental horticulture. Research focus areas discussed are: (1) responding to the changing climate (adaptation, mitigation and resilience solutions in gardens); (2) âplants for purposeâ (harnessing the potential of horticultural plant diversity, and gardening, to help regulate environmental conditions); (3) sustainability and climate risk reduction through effective and efficient resource management (reduction, re-use, recycling and repurposing); and (4) gardening and cultivated plant choice for human health and wellbeing. We argue that a key research priority is improving our understanding of the linkages and interactions between soil, water, plants, weather and people. These crucial linkages affect above and below ground processes, for both outdoor and indoor plants. They impact the effectiveness with which water and nutrient cycling takes place, the extent to which ecosystem services may be delivered, and the resultant capacity of gardens and gardening to provide environmental and human health benefits
Slow Light Propagation in a Thin Optical Fiber via Electromagnetically Induced Transparency
We propose a novel configuration that utilizes electromagnetically induced
transparency (EIT) to tailor a fiber mode propagating inside a thin optical
fiber and coherently control its dispersion properties to drastically reduce
the group velocity of the fiber mode. The key to this proposal is: the
evanescent-like field of the thin fiber strongly couples with the surrounding
active medium, so that the EIT condition is met by the medium. We show how the
properties of the fiber mode is modified due to the EIT medium, both
numerically and analytically. We demonstrate that the group velocity of the new
modified fiber mode can be drastically reduced (approximately 44 m/sec) using
the coherently prepared orthohydrogen doped in a matrix of parahydrogen crystal
as the EIT medium.Comment: 10 pages in two column RevTex4, 6 Figure
Equilibrium configurations of two charged masses in General Relativity
An asymptotically flat static solution of Einstein-Maxwell equations which
describes the field of two non-extreme Reissner - Nordstr\"om sources in
equilibrium is presented. It is expressed in terms of physical parameters of
the sources (their masses, charges and separating distance). Very simple
analytical forms were found for the solution as well as for the equilibrium
condition which guarantees the absence of any struts on the symmetry axis. This
condition shows that the equilibrium is not possible for two black holes or for
two naked singularities. However, in the case when one of the sources is a
black hole and another one is a naked singularity, the equilibrium is possible
at some distance separating the sources. It is interesting that for
appropriately chosen parameters even a Schwarzschild black hole together with a
naked singularity can be "suspended" freely in the superposition of their
fields.Comment: 4 pages; accepted for publication in Phys. Rev.
Intergenerational Community-Based Research and Creative Practice: Promoting Environmental Sustainability in Jinja, Uganda
This article critically reflects on the methodological approach developed for a recent project based in Jinja, Uganda, that sought to generate new forms of environmental knowledge and action utilizing diverse forms of creative intergenerational practice embedded within a broader framework of community-based participatory research. This approach provided new opportunities for intergenerational dialogue in Jinja, generated increased civic environmental engagement, and resulted in a participant-led campaign to share knowledge regarding sustainable biomass consumption. We term this approach intergenerational community-based research and creative practice. We discuss the advantages of this model while also reflecting throughout on the challenges of the approach
- âŠ