85 resultados para Restructuration productive
Resumo:
Relative sea-level rise has been a major factor driving the evolution of reef systems during the Holocene. Most models of reef evolution suggest that reefs preferentially grow vertically during rising sea level then laterally from windward to leeward, once the reef flat reaches sea level. Continuous lagoonal sedimentation ("bucket fill") and sand apron progradation eventually lead to reef systems with totally filled lagoons. Lagoonal infilling of One Tree Reef (southern Great Barrier Reef) through sand apron accretion was examined in the context of late Holocene relative sea-level change. This analysis was conducted using sedimentological and digital terrain data supported by 50 radiocarbon ages from fossil microatolls, buried patch reefs, foraminifera and shells in sediment cores, and recalibrated previously published radiocarbon ages. This data set challenges the conceptual model of geologically continuous sediment infill during the Holocene through sand apron accretion. Rapid sand apron accretion occurred between 6000 and 3000 calibrated yr before present B.P. (cal. yr B.P.); followed by only small amounts of sedimentation between 3000 cal. yr B.P. and present, with no significant sand apron accretion in the past 2 k.y. This hiatus in sediment infill coincides with a sea-level fall of similar to 1-1.3 m during the late Holocene (ca. 2000 cal. yr B.P.), which would have caused the turn-off of highly productive live coral growth on the reef flats currently dominated by less productive rubble and algal flats, resulting in a reduced sediment input to back-reef environments and the cessation in sand apron accretion. Given that relative sea-level variations of similar to 1 m were common throughout the Holocene, we suggest that this mode of sand apron development and carbonate production is applicable to most reef systems.
Resumo:
European flat oyster Ostrea edulis fisheries were once abundant around the UK coastline. The sole remaining productive O. edulis fishery in Scotland is in Loch Ryan. This fishery has been privately owned and managed by a single family since 1701. Economic theory predicts that ownership, whether public or private, is a necessary condition for rational fishery management. In this paper, a series of four leases and a licence are examined, covering an 85-year period over the 20th and 21st century, to examine whether the management of the Loch Ryan fishery conforms to the expected norms of rational management. The leases show that, over this period, the owners appear more willing to expend resources on regulating tenant behaviour, supporting the conclusion that successive generations of owners developed an evolving sense of what "rational management" might require. The results of this study could inform the management of other fisheries - both public and private - by emphasising the importance of learning from experience.
Resumo:
If cities are to become more sustainable and resilient to change it is likely that they will have to engage with food at increasingly localised levels, in order to reduce their dependancy on global systems. With 87 percent of developed regions estimated to be living in cities by 2050 it can be assumed that the majority of this localised production will occur in and around cities.
As part of a 12 month engagement, Queen’s University Belfast designed and implemented an elevated aquaponic food system spanning the top floor and exterior roof space of a disused mill in Manchester, England. The experimental aquaponic system was developed to explore the possibilities and difficulties associated with containing fish tanks, filtration units, vertical growing systems and roof top growing systems within and upon existing buildings, including the structural considerations needed when undertaking such transformations. Although capable of producing 4000 crops at any one time, the elevated aquaponic system utilised space within the existing building, which could otherwise be used as lettable area, and also located some crop growth within the building where light levels are reduced.
The following paper takes the research collected from the elevated aquaponic system and extrapolates the findings across a whole city. The resulting research enables the agricultural productive capacity of todays cities to be determined and a frame work of implementation to be developed for city wide food production. The research focuses specifically on facade and roof based systems, thus elevating the need to utilise lettable area within cities in addition to locating crops where light levels are highest.
Resumo:
A sediment record from a small lake in the north-eastern part of the Kamchatka Peninsula has been investigated in a multi-proxy study to gain knowledge of Holocene climatic and environmental change. Pollen, diatoms, chironomids and selected geochemical parameters were analysed and the sediment record was dated with radiocarbon. The study shows Holocene changes in the terrestrial vegetation as well as responses of the lake ecosystem to catchment maturity and multiple stressors, such as climate change and volcanic eruptions. Climate change is the major driving force resulting in the recorded environmental changes in the lake, although recurrent tephra deposition events also contributed. The sediment record has an age at the base of about 10,000 cal yrs BP, and during the first 400 years the climate was cold and the lake exhibited extensive ice-cover during winter and relatively low primary production. Soils in the catchment were poor with shrub alder and birches dominating the vegetation surrounding the lake. At about 9600–8900 cal yrs BP the climate was cold and moist, and strong seasonal wind stress resulted in reduced ice-cover and increased primary production. After ca. 8900 cal yrs BP the forest density increased around the lake, runoff decreased in a generally drier climate resulting in decreased primary production in the lake until ca. 7000 cal yrs BP. This generally dry climate was interrupted by a brief climatic perturbation, possibly attributed to the 8.2 ka event, indicating increasingly windy conditions with thick snow cover, reduced ice-cover and slightly elevated primary production in the lake. The diatom record shows maximum thermal stratification at ca. 6300–5800 cal yrs BP and indicates together with the geochemical proxies a dry and slightly warmer climate resulting in a high productive lake. The most remarkably change in the catchment vegetation occurred at ca. 4200 cal yrs BP in the form of a conspicuous increase in Siberian dwarf pine (Pinus pumila), indicating a shift to a cooler climate with a thicker and more long-lasting snow cover. This vegetational change was accompanied by marked shifts in the diatom and chironomid stratigraphies, which are also indicative of colder climate and more extensive ice-cover.
Resumo:
viii
Executive Summary
The Pathways Project field studies were targeted at improving the understanding of contaminant transport along different hydrological pathways in Irish catchments, including their associated impacts on water quality and river ecology. The contaminants of interest were phosphorus, nitrogen and sediment. The working Pathways conceptual model included overland flow, interflow, shallow groundwater flow, and deep groundwater flow. This research informed the development of a set of Catchment Management Support Tools (CMSTs) comprising an Exploratory Tool, Catchment Characterization Tool (CCT) and Catchment Modelling Tool (CMT) as outlined in Pathways Project Final Reports Volumes 3 and 4.
In order to inform the CMST, four suitable study catchments were selected following an extensive selection process, namely the Mattock catchment, Co. Louth/Meath; Gortinlieve catchment, Co. Donegal; Nuenna catchment, Co. Kilkenny and the Glen Burn catchment, Co. Down. The Nuenna catchment is well drained as it is underlain by a regionally important karstified limestone aquifer with permeable limestone tills and gravels, while the other three catchments are underlain by poorly productive aquifers and low permeability clayey tills, and are poorly drained.
All catchments were instrumented, and groundwater, surface and near-surface water and aquatic ecology were monitored for a period of two years. Intensive water quality sampling during rainfall events was used to investigate the pathways delivering nutrients. The proportion of flow along each pathway was determined using chemical and physical hydrograph separation techniques, supported by numerical modelling.
The outcome of the field studies broadly supported the use of the initial four-pathway conceptual model used in the Pathways CMT (time-variant model). The artificial drainage network was found to be a significant contributing pathway in the poorly drained catchments, at low flows and during peak flows in wet antecedent conditions. The transition zone (TZ), i.e. the broken up weathered zone at the top of the bedrock, was also found to be an important pathway. It was observed to operate in two contrasting hydrogeological scenarios: in groundwater discharge zones the TZ can be regarded as being part of the shallow groundwater pathway, whereas in groundwater recharge zones it behaves more like interflow.
In the catchments overlying poorly productive aquifers, only a few fractures or fracture zones were found to be hydraulically active and the TZ, where present, was the main groundwater pathway. In the karstified Nuenna catchment, the springs, which are linked to conduits as well as to a diffuse fracture network, delivered the majority of the flow. These findings confirm the two-component groundwater contribution from bedrock but suggest that the size and nature of the hydraulically active fractures and the nature of the TZ are the dominant factors at the scale of a stream flow event.
Diffuse sources of nitrate were found to be typically delivered via the subsurface pathways, especially in the TZ and land drains in the poorly productive aquifer catchments, and via the bedrock groundwater in the Nuenna. Phosphorus was primarily transported via overland flow in both particulate and soluble forms. Where preferential flow paths existed in the soil and subsoil, soluble P, and to a lesser extent particulate P, were also transported via the TZ and in drains and ditches. Arable land was found to be the most important land use for
ix
the delivery of sediment, although channel bank and in-stream sources were the most significant in the Glen Burn catchment. Overland flow was found to be the predominant transport sediment pathway in the poorly productive catchments. These findings informed the development of the transport and attenuation equations used in the CCT and CMT. From an assessment of the relationship between physico-chemical and biological conditions, it is suggested that in the Nuenna, Glen Burn and Gortinlieve catchments, a relationship may exist between biological water quality and nitrogen concentrations, as well as with P. In the Nuenna, there was also a relationship between macroinvertebrate status and alkalinity.
Further research is recommended on the transport and delivery of phosphorus in groundwater, the transport and attenuation dynamics in the TZ in different hydrogeological settings and the relationship between macroinvertebrates and co-limiting factors. High resolution temporal and spatial sampling was found to be important for constraining the conceptual understanding of nutrient and sediment dynamics which should also be considered in future studies.
Resumo:
Following the collapse of the Soviet Union in 1991, the newly independent oil-rich country of Kazakhstan has become a major recipient of foreign direct investment (FDI). Although international organisations such as the IMF and UNCTAD have claimed that FDI could be considered an engine in the transition from state socialism and as a powerful force for integration of this region into the global economy; this investment also poses significant risks to Kazakhstan. These risks fall into two broad categories: The first category can be broadly described as issues associated with the “resource curse” or the “Dutch Disease”. The term Dutch Disease describes a situation where booming demand in oil exporting countries, due to high oil revenues, leads to shift of an economy’s productive resources from the tradeable sector to the non-tradeable sector. The second category is associated with the over-dependency of oil exporting countries on a relatively small number of large multinational corporations (MNCs). This over-dependency can lead to a situation where licenses and concessions are granted at less favourable conditions than if they were auctioned in an efficient market. Examining the licensing policy of the Kazakhstani Energy and Mineral Resource Ministry, this paper notes that the latter issue of over-dependency has become less of a risk due to deliberate efforts to diversify investment relationships. Notwithstanding this situation there is some evidence that it remains difficult for oil exporting nations such as Kazakhstan to ensure that oil revenues are channelled into sustainable economic development.
Resumo:
Sustainability can be described as having three interlinked strands, known as the ‘trias energetica’, without which resilience is difficult to achieve. These strands are environmental, social and economic: and if taken as indicators, the suburbs of North Belfast are very poorly performing indeed. Places such as Ligoneal and Glen Cairn have poor housing stock energetically, and also little economic activity. This paper describes propositional work completed by Queens University and Belfast City Council as part of the UK’s Technology Strategy Board’s Future Cities Programme, which aimed to develop new synergies in these neighbourhoods by the insertion of closed cycle economies.
By utilising a research by design methodology, the paper develops a process-based and phased design to develop a new emergent form to these neighbourhoods, one in which new productive systems are embedded into the city, at a small-scales. These include a peak-load hydro-electric project in Ligoneal; a productive landscape in Glen Cairn and a city-wide energy refurbishment utilising neighbourhood waste streams.
These designs allow for a roadmap for development to be created that could change the modus operandi of an area over a relatively short period of time, and show that even modest investments of productive technologies at a local scale could fundamentally change the form and the economic and environmental operation of the city in the future, and create a new resilient city, one that can be less externally dependent and more socially just.
Resumo:
By utilising a research by design methodology, the paper develops a process-based and phased design to develop a new emergent form to these neighbourhoods, one in which new productive systems are embedded into the city, at a small-scales. These include a peak-load hydro-electric project in Ligoneal; a productive landscape in Glen Cairn and a city-wide energy refurbishment utilising neighbourhood waste streams.
The three projects illustrate different ways in which place-based solutions can enact urban transformation through a process of rigorous visualisation of process, and its attendant changes in content and form of the neighbourhood, These designs, based around a process-based strategy plan, allow for a roadmap for development to be created that could change the modus operandi of an area over a relatively short period of time,. The paper demonstrates that even modest investments of productive technologies at a local scale can fundamentally change the form and the economic and environmental operation of the city in the future, and create a new resilient city, one that can have resilience built-in. This resilience allows the neighbourhood to be less externally dependent on resources, economically active and more socially just.
Resumo:
This book is the transcript of a public lecture given in Mar 2014 in Velp NL. The text and images are presented in Dutch and English. The lecture describes a range of possibilities for the city of tomorrow as a productive landscape.
Resumo:
Tenure-track contract is criticized for curbing the incentives to expend effort after obtaining tenured status. Yet the most productive faculties seem to work on a tenure contract, and schools which aim to employ the best faculty seem to prefer to offer tenure-track contracts to their new recruits. I argue that tenure-track contracts are by construction more attractive to more able freshly minted PhDs, and therefore the observed sorting is rationalizable.