1,327 research outputs found
AN ECOSYSTEM FRAMEWORK FOR FISHERIES MANAGEMENT IN THE SOUTHERN BENGUELA UPWELLING SYSTEM
A âfour-step frameworkâ for applying ecosystem approaches to fisheries management in the southern Benguela is proposed. First, static ecosystem models can be used to highlight important interactions by assessing the net trophic impacts of each species on all the others. Second, using a dynamic simulation approach, indicators quantifying interaction strength and functional impacts can provide information on the size of impacts on ecosystem components when a group is overfished. Third, dynamic simulations can suggest some possible short- and long-term ecosystem effects of altered fishing under strategies developed and selected using standard single-species models. Finally, the net combined ecosystem effects of the revised strategies for all fisheries in the ecosystem need to be considered together. For this to be accomplished, overall objectives for regional fisheries
management, objectives for each fishery, and non-consumptive objectives need to be clearly stated and carefully considered in the provision of advice in an ecosystem context. A selected theoretical fishing strategy is examined to explore the possible ecosystem effects of implementing an option such as this in the southern Benguela ecosystem.Afr. J. mar. Sci. 26: 63â7
Using decision analysis to evaluate candidate OMPs for the South African west coast rock lobster fishery
Simulation models frequently are used to provide information to
assist in decision-making in natural resource management. The
sheer volume of information to process can be overwhelming,
however, and there is a danger that some management objectives
are not adequately considered, because of the difficulties of
making decisions when there are multiple, conflicting objectives.
Formal decision-analysis methods have been used in conservation
biology to choose among simulation model results. This paper
suggests that they can also be used in South African fisheries
management, where simulation models are used extensively in
developing operational management procedures
CONTRIBUTIONS OF THE BENGUELA ECOLOGY PROGRAMME TO PELAGIC FISHERIES MANAGEMENT IN SOUTH AFRICA
In 1982, the Benguela Ecology Programme (BEP) created a formal, multi-institutional research partnership in South Africa. During the next two decades, the BEP directed many aspects of pelagic ecosystem research in the southern Benguela upwelling region, aiming to improve fisheries management, particularly that of anchovy Engraulis encrasicolus. Although much reduced in scale, the BEP is now in its fifth phase. Its early critics believed that much of the money invested in its ecosystem-type research had not benefited fisheries management, whereas its supporters maintain that many aspects of current pelagic fisheries management are founded on the BEP legacy. Ecosystem research underpinned the design of hydroacoustic surveys, and resulted in the development of expert system models aimed at predicting recruitment strength of anchovy. Current efforts to develop an ecosystem approach to management of the pelagic fishery in South Africa draw on the knowledge and understanding generated by more than 20 years of ecosystem research. However, despite this strong foundation, there is still uncertainty about the causes of interannual variability in pelagic fish recruitment. It is suggested that this time span is too short, and ecosystem monitoring and research should persist for decades to reap their full rewards. The BEP enabled productive partnerships to be established between academic and State researchers and fisheries managers, and improved linkages and communication to the fishing industry. Afr. J. mar. Sci. 26: 37â5
The great Australian nightmare? The problem of escalating housing aspirations and expectations and adaptation to climate change
The dominant trend in Australian cities towards large, detached, energy intensive dwellings in poorly serviced, low-density, urban fringe locations, leaves governments, households and communities more vulnerable to the impacts of climate change and does little to aid mitigation. Given the multiple and competing objectives of the stakeholders involved, reducing domestic energy consumption is more complex than attempting to change what Shove (2010) refers to as the ABC ('attitudes, behaviours and choices') of individual householders. What is needed is a better understanding of the dynamic and integrated processes resulting in escalating expectations and aspirations for Australian housing. Along this vein, we suggest the 'great Australian dream' is actually becoming a great Australian nightmare. In our critique we investigate what is meant by a 'normal' home and how aspirations and expectations for housing have changed over time. Drawing on theories of social practice we look at what goes on inside homes to explore how everyday practices and the design of houses are mutually constitutive. In our analysis we find that seemingly common-place aspirations for housing are the result of changing practices, such as cooking, eating and entertaining, which are resulting in escalating trajectories of consumption. We conclude by suggesting how policy attention could be refocused on transforming the relationship between house design and everyday practice to address climate change
ECOSYSTEM APPROACH TO FISHERIES MANAGEMENT IN THE SOUTHERN BENGUELA: A WORKSHOP OVERVIEW
A workshop was held in Cape Town in December 2002 to introduce the concept of an ecosystem approach to
fisheries (EAF) management in the southern Benguela, and to examine the options for implementing an EAF in
South Africa. The workshop considered alternative modelling approaches that may have potential for an ecosystem
approach to fisheries. Consensus was that an EAF should be implemented in South Africa through an incremental
process, starting immediately. Ecosystem models can be used to provide guidance on reference points and
broader management objectives still currently set on the basis of single-species assessments. Such additional information
would be incorporated into the decision-making process, and comments received at a management
level would also feed back to the modelling process. It was suggested that, at the scientific level, an ecosystem
modelling perspective could be incorporated into existing single-species management recommendations by testing
them with ecosystem models. Compilation of an âecosystem considerationsâ document was recommended to
initiate the process. It was proposed that a dedicated EAF working group be established in South Africa to advise
on the process of implementing an EAF in the various fisheries, and to provide overarching guidance and to ensure
consistency in integrating existing data and information for informing the management process
Pro-survival redox signalling in progesterone-mediated retinal neuroprotection
Retinitis pigmentosa (RP) is a group of hereditary retinal diseases, characterised by photoreceptor cell loss. Despite a substantial understanding of the mechanisms leading to cell death, an effective therapeutic strategy is sought. Our laboratory has previously demonstrated the neuroprotective properties of Norgestrel, a progesterone analogue, in the degenerating retina, mediated in part by the neurotrophic factor basic fibroblast growth factor (bFGF). In other retinal studies, we have also presented a pro-survival role for reactive oxygen species (ROS), downstream of bFGF. Thus, we hypothesized that Norgestrel utilises bFGF-driven ROS production to promote photoreceptor survival. Using the 661W photoreceptor-like cell line, we now show that Norgestrel, working through progesterone receptor membrane complex 1 (PGRMC1); generates an early burst of pro-survival bFGF-induced ROS. Using the rd10 mouse model of RP, we confirm that Norgestrel induces a similar early pro-survival increase in retinal ROS. Norgestrel-driven protection in the rd10 retina was attenuated in the presence of antioxidants. This study therefore presents an essential role for ROS signalling in Norgestrel-mediated neuroprotection in vitro and demonstrates that Norgestrel employs a similar pro-survival mechanism in the degenerating retina
Progesterone analogue protects stressed photoreceptors via bFGF-mediated calcium influx.
Retinitis pigmentosa (RP) is a degenerative retinal disease leading to photoreceptor cell loss. In 2011, our group identified the synthetic progesterone âNorgestrelâ as a potential treatment for RP. Subsequent research showed Norgestrel to work through progesterone receptor membrane component 1 (PGRMC1) activation and upregulation of neuroprotective basic fibroblast growth factor (bFGF). Using trophic factor deprivation of 661W photoreceptor-like cells, we aimed to further elucidate the mechanism leading to Norgestrel-induced neuroprotection. In the present manuscript, we show by flow cytometry and live-cell immunofluorescence that Norgestrel induces an increase in cytosolic calcium in both healthy and stressed 661Ws over 24h. Specific PGRMC1 inhibition by AG205 (1 ÎźM) showed this rise to be PGRMC1-dependent, primarily utilising calcium from extracellular sources, for blockade of L-type calcium channels by verapamil (50 ÎźM) prevented a Norgestrel-induced calcium influx in stressed cells. Calcium influx was also shown to be bFGF-dependent, for siRNA knock down of bFGF prevented Norgestrel-PGRMC1 induced changes in cytosolic calcium. Notably, we demonstrate PGRMC1-activation is necessary for Norgestrel-induced bFGF upregulation. We propose that Norgestrel protects through the following pathway: binding to and activating PGRMC1 expressed on the surface of photoreceptor cells, PGRMC1 activation drives bFGF upregulation and subsequent calcium influx. Importantly, raised intracellular calcium is critical to Norgestrel's protective efficacy, for extracellular calcium chelation by EGTA abrogates the protective effects of Norgestrel on stressed 661W cells in vitro
Using airborne LiDAR Survey to explore historic-era archaeological landscapes of Montserrat in the eastern Caribbean
This article describes what appears to be the first archaeological application of airborne LiDAR survey to historic-era landscapes in the Caribbean archipelago, on the island of Montserrat. LiDAR is proving invaluable in extending the reach of traditional pedestrian survey into less favorable areas, such as those covered by dense neotropical forest and by ashfall from the past two decades of active eruptions by the Soufrière Hills volcano, and to sites in localities that are inaccessible on account of volcanic dangers. Emphasis is placed on two aspects of the research: first, the importance of ongoing, real-time interaction between the LiDAR analyst and the archaeological team in the field; and second, the advantages of exploiting the full potential of the three-dimensional LiDAR point cloud data for purposes of the visualization of archaeological sites and features
Spatiotemporal communication with synchronized optical chaos
We propose a model system that allows communication of spatiotemporal
information using an optical chaotic carrier waveform. The system is based on
broad-area nonlinear optical ring cavities, which exhibit spatiotemporal chaos
in a wide parameter range. Message recovery is possible through chaotic
synchronization between transmitter and receiver. Numerical simulations
demonstrate the feasibility of the proposed scheme, and the benefit of the
parallelism of information transfer with optical wavefronts.Comment: 4 pages, 5 figure
Treatments for hyperemesis gravidarum and nausea and vomiting in pregnancy: a systematic review and economic assessment
Background: Nausea and vomiting in pregnancy (NVP) affects up to 85% of all women during pregnancy, but for the majority self-management suffices. For the remainder, symptoms are more severe and the most severe form of NVP - hyperemesis gravidarum (HG) - affects 0.3-1.0% of pregnant women. There is no widely accepted point at which NVP becomes HG.Objectives: This study aimed to determine the relative clinical effectiveness and cost-effectiveness of treatments for NVP and HG.Data sources: MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, PsycINFO, Commonwealth Agricultural Bureaux (CAB) Abstracts, Latin American and Caribbean Health Sciences Literature, Allied and Complementary Medicine Database, British Nursing Index, Science Citation Index, Social Sciences Citation Index, Scopus, Conference Proceedings Index, NHS Economic Evaluation Database, Health Economic Evaluations Database, China National Knowledge Infrastructure, Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects were searched from inception to September 2014. References from studies and literature reviews identified were also examined. Obstetric Medicine was hand-searched, as were websites of relevant organisations. Costs came from NHS sources.Review methods: A systematic review of randomised and non-randomised controlled trials (RCTs) for effectiveness, and population-based case series for adverse events and fetal outcomes. Treatments: vitamins B6 and B12, ginger, acupressure/acupuncture, hypnotherapy, antiemetics, dopamine antagonists, 5-hydroxytryptamine receptor antagonists, intravenous (i.v.) fluids, corticosteroids, enteral and parenteral feeding or other novel treatment. Two reviewers extracted data and quality assessed studies. Results were narratively synthesised; planned meta-analysis was not possible due to heterogeneity and incomplete reporting. A simple economic evaluation considered the implied values of treatments.Results: Seventy-three studies (75 reports) met the inclusion criteria. For RCTs, 33 and 11 studies had a low and high risk of bias respectively. For the remainder (n = 20) it was unclear. The non-randomised studies (n = 9) were low quality. There were 33 separate comparators. The most common were acupressure versus placebo (n = 12); steroid versus usual treatment (n = 7); ginger versus placebo (n = 6); ginger versus vitamin B6 (n = 6); and vitamin B6 versus placebo (n = 4). There was evidence that ginger, antihistamines, metoclopramide (mild disease) and vitamin B6 (mild to severe disease) are better than placebo. Diclectin (R) [Duchesnay Inc.; doxylamine succinate (10 mg) plus pyridoxine hydrochloride (10 mg) slow release tablet] is more effective than placebo and ondansetron is more effective at reducing nausea than pyridoxine plus doxylamine. Diclectin before symptoms of NVP begin for women at high risk of severe NVP recurrence reduces risk of moderate/severe NVP compared with taking Diclectin once symptoms begin. Promethazine is as, and ondansetron is more, effective than metoclopramide for severe NVP/HG. I.v. fluids help correct dehydration and improve symptoms. Dextrose saline may be more effective at reducing nausea than normal saline. Transdermal clonidine patches may be effective for severe HG. Enteral feeding is effective but extreme method treatment for very severe symptoms. Day case management for moderate/severe symptoms is feasible, acceptable and as effective as inpatient care. For all other interventions and comparisons, evidence is unclear. The economic analysis was limited by lack of effectiveness data, but comparison of costs between treatments highlights the implications of different choices.Limitations: The main limitations were the quantity and quality of the data available.Conclusion: There was evidence of some improvement in symptoms for some treatments, but these data may not be transferable across disease se
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