Weed control strategies in organically grown carrots

This paper outlines a study to integrate elements of cultural, thermal and mechanical control methods in the production of late maincrop drilled organic carrots. Agronomic and economic findings are discusse

Horticultural weed control in organic systems – a modelling approach

This report was presented at the UK Organic Research 2002 Conference. Weed control is an important yet mainly unaddressed research issue in organic systems. At present there is little agronomic support to underpin weed management decisions. Computer modelling and simulation techniques may provide a valuable tool for understanding the nature and processes of the organic system thus generating knowledge and information of direct benefit to growers, which will aid in short and long term weed management strategies

Fertility building strategies during the conversion period – assessment of performance in a stockless field vegetable rotation

This report was presented at the UK Organic Research 2002 Conference of the Colloquium of Organic Researchers (COR). Nutrient off-takes, residue returns and nutrient inputs were measured during and after conversion from a conventional arable system to organic vegetables with cereals. This data was used to construct nutrient budgets to assess the effectiveness of contrasting fertility building strategies and various cropping regimes. The effect of placing the cereal crops in different places in the crop sequence was also considered

LATE QUATERNARY FIRE HISTORIES IN THE EASTERN MEDITERRNEAN REGION FROM LAKE SEDIMENTARY MICRO-CHARCOALS

The Eastern Mediterranean has a long history of human occupation, which spans the transition from hunter-gatherers to the establishment of early agro-pastoralist communities, coinciding with the Last Glacial: Interglacial transition. Over the same timeframe a delay in post glacial woodland recolonisation in the region has been identified. Fire has long been used by people to manage and manipulate the landscape, and has been hypothesised to have played a role in this delay. This thesis employed lacustrine microcharcoal (particles less than 180 µm) remains to reconstruct Late Quaternary fire histories for Central Turkey and the Levant, and examine the possible role that fire may have played in retarding woodland development in the region. Microcharcoals were analysed in cores taken from four sites in Central Turkey (Akgol, Eski Acigol, Catalhoyuk and Nar Golu) and one site in Israel (Lake Hula) that cover varying time intervals from the Last Glacial through to the Late Holocene. In order to develop a standardised analytical procedure for microcharcoals, a series of published extraction and quantification techniques along with a new approach using heavy liquid separation were rigorously tested on "control" samples that contained a known volume of microscopic charcoal. As a result of this investigation a novel, two step extraction procedure based on the use of heavy liquid separation was developed and applied alongside a contiguous high resolution sampling strategy. Using this approach, fire activity was reconstructed based on cores from each of the sites and these data were compared with existing multi-proxy data (stable oxygen isotopes, pollen and archaeological data). Results show clear links between climate, biomass, people and fire, although these relationships changed over time. Regional fire activity during the Last Glacial: Holocene transition was apparently controlled by climate through the influence it exerted on biomass availability, whereas links between people and fire activity are most evident during the Late Holocene. Humans do not seem to have retarded the Early Holocene spread of woodland through the use of fires, although it is possible that natural fire activity served to maintain the open parkland vegetation communities may have played a role. During the Mid Holocene a mixture of climatic and anthropogenic controls apparently influenced regional fire activity. Evidence was also identified of a ca.l,500 year periodicity in fire history from Central Turkey which may reflect teleconnections to climatic changes in the North Atlantic. This research also highlighted the potential of using microscopic charcoal to infer the spatial resolution of fire history reconstructions from lake basins of different sizes and types through comparisons of influx values

Late Quaternary fire histories in the eastern Mediterranean region from lake sedimentary micro-charcoals

The Eastern Mediterranean has a long history of human occupation, which spans the transition from hunter-gatherers to the establishment of early agro-pastoralist communities, coinciding with the Last Glacial: Interglacial transition. Over the same timeframe a delay in postglacial woodland recolonisation in the region has been identified. Fire has long been used by people to manage and manipulate the landscape, and has been hypothesised to have played a role in this delay. This thesis employed lacustrine micro charcoal (particles less than 180 !lm) remains to reconstruct Late Quaternary fire histories for Central Turkey and the Levant, and examine the possible role that fire may have played in retarding woodland development in the region. Microcharcoals were analysed in cores taken from four sites in Central Turkey (AkgOl, Eski AClgol, <;atalhOyiik and Nar Golii) and one site in Israel (Lake Hula) that cover varying time intervals from the Last Glacial through to the Late Holocene. In order to develop a standardised analytical procedure for microcharcoals, a series of published extraction and quantification techniques along with a new approach using heavy liquid separation were rigorously tested on "control" samples that contained a known volume of microscopic charcoal. As a result of this investigation a novel, two step extraction procedure based on the use of heavy liquid separation was developed and applied alongside a contiguous high resolution sampling strategy. Using this approach, fire activity was reconstructed based on cores from each of the sites and these data were compared with existing multi-proxy data (stable oxygen isotopes, pollen and archaeological data). Results show clear links between climate, biomass, people and fire, although these relationships changed over time. Regional fire activity during the Last Glacial: Holocene transition was apparently controlled by climate through the influence it exerted on biomass availability, whereas links between people and fire activity are most evident during the Late Holocene. Humans do not seem to have retarded the Early Holocene spread of woodland through the use of fires, although it is possible that natural fire activity served to maintain the open parkland vegetation communities may have played a role. During the Mid Holocene a mixture of climatic and anthropogenic controls apparently influenced regional fire activity. Evidence was also identified of a ca.l ,500 year periodicity in fire history from Central Turkey which may reflect teleconnections to climatic changes in the North Atlantic. This research also highlighted the potential of using microscopic charcoal to infer the spatial resolution of fire history reconstructions from lake basins of different sizes and types through comparisons of influx values

Triphenylene as a Scaffold for New Molecular Materials

The work described in this thesis centres around our desire to use triphenylene as the scaffold for building new molecular materials. This has been approached in three different ways; firstly a twin linked by pyrrole units, secondly by twinning with triazoles, and finally via the formylation of triphenylene. A tetra-hexyloxysubstituted dipyrrolyltriphenylene twin had previously been synthesised in the group, however characterisation was difficult and therefore a twin with improved solubility was designed. The synthesis of tetra-decyloxysubstituted dipyrrolyltriphenylene was completed successfully, but the twinning of the compound could not be achieved. One possible explanation was interference of the long alkyl chains in the neighbouring positions to the pyrrole units. A new target precursor was designed with just two alkyl chains on the triphenylene. Previous work in the group had shown difficulties in the synthesis of the di-hexyloxysubstituted triphenylene, however with careful manipulations the synthesis was successful. New complications were found with the solubility of the di-hexyloxysubstituted dipyrrolyltriphenylene that could not be overcome. At this point crystals of the tetra-hexyloxysubstituted dipyrrolyltriphenylene twin had been obtained and full characterisation achieved. With the explosion of Click chemistry in the recent years, a twin linked by triazoles was targeted. The twin was designed from a tetra-hexyloxysubstituted diazidetriphenylene, coupled with di-hexyloxysubstituted diacetylenetriphenylene. The diacetylene triphenylene was synthesised successfully following on from the work achieved in the first project. Two routes were explored for the synthesis of the diazide. The first, a direct conversion of the dibromide to the diazide, gave no reaction. The second route was a series of manipulations starting from the dinitrotriphenylene. Some difficulties were found with the reduction of the dinitro compound to the diamine, however these were overcome using carefully controlled conditions. The corresponding diamide was synthesised to allow for full characterisation, as the diamine was found to decompose rapidly. Crystals were grown of the diamide and the x-ray structure was obtained, this showed an unexpected structure. The expected 3,6-substitution pattern had not been formed, in fact we had synthesised the 1,8-bisimide-2,7,10,11-tetrakis(hexyloxy) triphenylene. As the triazole linked triphenylene twin was not accessible, the diacetylenetriphenylene was twinned with itself. High dilution conditions were followed and the twin was successfully isolated. The twin showed no mesophase behaviour and remained stable beyond 300 oC. The third part of the thesis is based on the formylation of tetra-hexyloxysubstituted triphenylene. The formation of the triphenylene dialdehyde had previously eluded our group, however following a new protocol gave a successful synthesis. There were a number of potential compounds to investigate from this versatile precursor. We chose to target BODIPY-triphenylene hybrid compounds. Two compounds were designed, one from the dialdehyde where the BODIPY fragment would be attached via the central meso-carbon, and one from the dipyrrole where the BODIPY would be attached via the alpha positions of the pyrrole. Kryptopyrrole was used in the synthesis from the dipyrrole, to attempt to discourage potential polymer formation, however the reactions were not successful. The bis-BODIPYtriphenylene via the dialdehyde was successfully synthesised and the compound was observed for potential mesophase behaviour; it was seen to melt with decomposition at 150-160 oC. Finally, the triphenylene dialdehyde was used to synthesise a twin linked by diamines. The novel twinned structure has a central “void” region that we know to disfavour columnar organisation. The compound was observed for potential mesophase behaviour, and the twin was seen to exhibit only a stable nematic discotic mesophase up to 300 oC

A kinetic model describing the processivity of Myosin-V

The precise details of how myosin-V coordinates the biochemical reactions and mechanical motions of its two head elements to engineer effective processive molecular motion along actin filaments remain unresolved. We compare a quantitative kinetic model of the myosin-V walk, consisting of five basic states augmented by two further states to allow for futile hydrolysis and detachments, with experimental results for run lengths, velocities, and dwell times and their dependence on bulk nucleotide concentrations and external loads in both directions. The model reveals how myosin-V can use the internal strain in the molecule to synchronize the motion of the head elements. Estimates for the rate constants in the reaction cycle and the internal strain energy are obtained by a computational comparison scheme involving an extensive exploration of the large parameter space. This scheme exploits the fact that we have obtained analytic results for our reaction network, e.g., for the velocity but also the run length, diffusion constant, and fraction of backward steps. The agreement with experiment is often reasonable but some open problems are highlighted, in particular the inability of such a general model to reproduce the reported dependence of run length on ADP concentration. The novel way that our approach explores parameter space means that any confirmed discrepancies should give new insights into the reaction network model

The Loop: A Plan for the Future of Rogers

Storm water management in urban areas is not only a necessary infrastructure, it is also a valuable resource to provide an aesthetic experience for the public while furthering ecological awareness, recreation, and the cultural fabric. Through the restructuring of current development ordinances and through greater attention to the true needs of the natural and built communities, storm water management becomes the tool to breach the gap between man and nature. Rogers, Arkansas, a city of exciting and alarming growth, maintains traditional planning and environmental practices that have created a center of disequilibrium among the natural and built systems. Local streams and their surrounding environment have received the worst of this imbalance as flooding, severe stream-channel erosion, loss of wetland habitat, and riparian ecosystems have become dominating characteristics. Differing principles and goals of Rogers\u27 major municipalities and special interest groups are the catalysts for the overall degradation of the natural systems. As the stream corridors continue to decline, the actual tools needed to stop this decline remain in great debate, varying from engineering tactics to a closed-door, political approach. The greatest challenge to the stream corridors continue to decline, the actual tools needed to stop this decline remain in great debate, varying from engineering tactics to a closed-door, political approach. The greatest challenge to the city of Rogers and to the overall health of the environment, lies in synthesizing the needs, principles, and practices of each group into a harmonious whole. The object of this amalgamation is not only to solve stream quality issues, but also to allow the city to capitalize on the potential benefits of its stream corridors. The Loop is a multi-objective recreation and urban design project that illustrates the potential of using stream corridor restoration as a springboard into several other realms of city planning and urban design. However, in order to achieve a successful project, extensive studies in civil engineering, local historic and cultural patterns, and land management theories were necessary. A tri-fold, tri-pan harmony, The Loop executes an integration of these design principles in the fields of ecology, recreation, and urban design. Using the stream corridors, city easements, cultural and social connectors, and the apparent new development, The Loop serves as medium by which to solve ecological problems, to provide extensive recreation opportunities, and to create a cohesive urban fabric. The Loop also serves to provide alternatives to typical development practices. By incorporating a task force composed of local elected officials, local land planners, engineers, special-interest groups, and community members, all provisions work together to create positive multiple, mutually reinforcing, long-term benefits, while satisfying the needs of each group. Future development will be governed by these principles and will benefit and strengthen the ecological and social framework of the city. The Loop, through these provisions, strives to establish a balanced system that improves the surrounding environment and provides an ecologically sound, esthetically pleasing experience. The Loop, a development plan for the future of Rogers, Arkansas, is the catalyst to form a model city in the heart of Northwest Arkansas. By brandishing new techniques that not only improve the quality of life but also guarantee the continuum and health of the natural systems, Rogers establishes itself as a city and a community with a common vision and a brighter future

Slowly Realizing the Other: A Creative Examination of a World Outside the Familiar

In this thesis I explore the importance of imagining others complexly, especially members of other cultures whom Westerners tend to view through the lens of stereotype. Rather than seeking to directly quote theory and criticism, though, I consider the implications of these ideas through fiction. A British businessman traveling to the Philippines on holiday encounters Typhoon Yolanda, one of the largest storms in recorded history. Suddenly stranded, Gary must expand his view of the world, realizing (perhaps for the first time) that his status does not make him more—or less—important than anyone else he might encounter