189 research outputs found

    Under the radar? 'Soft' residential densification in England, 2001-2011

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    Urban compaction policies have been widely adopted in developed countries in pursuit of more sustainable cities. Compactness is achieved through a process of ‘densification’, of developing and using land and buildings more intensively. However, empirical evidence on the processes and outcomes of urban densification is lacking. The paper addresses this lacuna. It considers densification in England, a country that has long experience of applying policies of urban containment and consolidation; and one where new data sources allow the analysis of recent land use change at a level of detail not hitherto possible. In England between 2001 and 2011 the bulk of additional dwellings were accommodated within urban areas, increasing their density. Yet there were wide inter- and intra-regional variations in the pattern of densification: for example, in the contributions of large scale, formal development and of small scale, informal, gradual change – of ‘hard’ and ‘soft’ densification – to the process. The significant differences in local experiences of densification that result raise major issues for policy

    Qualitative and quantitative analysis of lipid classes in fish oils by thin-layer chromatography with an Iatroscan flame Ionization detector (TLC-FID) and liquid chromatography with an evaporative light scattering detector (LC-ELSD)

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    Combined effects of hydrogen and air flow rates on the peak response of selected neutral lipid classes (triacylglycerol, diacylglycerol, monoacylglycerol, free fatty acids, and ethyl esters) were studied to optimize and calibrate the Iatroscan Mk-6s Chromarod system for the qualitative and quantitative analysis of lipid classes by thin-layer chromatography (TLC) with flame ionization detection in fish oil during the transesterification process. Air flow rate of 2 L/min, hydrogen flow rate of 150-160 mL/min, and scan rate of 30 s/rod were found to be the optimum conditions. All samples were also analyzed by high performance liquid chromatography (HPLC) with evaporative light scattering detection. Quantitative results obtained by TLC with the flame ionization detection method were comparable to those obtained from HPLC with evaporative light scattering detection. <br /

    History, current status, and collaborative researchprojects for Bemisia tabaci

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    Bemisia tabaci was described over 100 years ago and has since become one of the most important pests worldwide in subtropical and tropical agriculture as well as in greenhouse production systems. It adapts easily to new host plants and geographical regions and has now been reported from all global continents except Antarctica. In the last decade, international transport of plant material and people have contributed to geographical spread. B. tabaci has been recorded from more than 600 plant species and there may be many additional hosts not yet formally documented. Biotypes have been identified in different areas of the world suggesting that B. tabaci may be a species-complex undergoing evolutionary change. These biotypes may exhibit differences in viruses transmitted and transmission efficiency, rates of development, endosymbionts, host utilization, and physiological host damage. Excessive B. tabaci induced losses worldwide occur in field, vegetable and ornamental crop production. Losses occur from plant diseases caused by B. tabaci transmitted viruses, direct feeding damage, plant physiological disorders, and honeydew contamination and associated fungal growth. The number of B. tabaci-transmitted plant viruses has increased, and total yield losses of important food and industrial crops has occurred. Effective control at present is dependent on insecticides. However, this has been achieved with more selective chemistries, use of action thresholds, and resistance management. Host plant resistance and various cultural methods are also components of developing integrated management systems. National and international collaborative projects have made significant progress towards improved characterization of the whitefly problem, increased research, development of management methods, transfer of technology to the agricultural communities, and information exchange. These projects, as well as intensive education, research and extension activities form the basis for biologically and ecologically based approaches to management

    Organic and Conventional Vegetable Production in Oklahoma

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    This study compares he profitability and risk related to conventional and organic vegetable production systems A linear programming model was used to find the optimal mix of vegetables in both production systems. And a target MOTAD (minimization of total absolute deviation) model was used to perform risk analysis in both organic and conventional production systemsCrop Production/Industries, Research Methods/ Statistical Methods,

    The perception and management of risk in UK office property development

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    Risk is an ever-present aspect of business, and risk taking is necessary for profit and economic progress. Speculative property development is popularly perceived as a 'risky business' yet, like other entrepreneurs, developers have opportunities to manage the risks they face; techniques include phasing and joint ventures. The associated areas of investment portfolio risk, development risk analysis and construction risk management have all been addressed by research. This article presents new knowledge about how developers perceive risks and the means they subsequently adopt to manage them. The developers of office projects across the UK were sent questionnaires by post. Respondents were asked about their perceptions of risks at the first appraisal stage and currently and about the risk management techniques that they had adopted. In-depth interviews with a selection of respondents were then used to discuss and augment the findings. Developers were most concerned about market-based risks at both stages. Concern about production-orientated risks was lower and fell significantly between the two stages. A fixed price contract was the most common risk management technique. Risk management techniques were used more often outside London and the South East. Developer type affects both the perception and management of risk. While developers do manage risk, decisions are made on the basis of professional and business experience. These findings should help development companies manage risk in a more objective and analytical way

    Novel Pink Bollworm Resistance to the Bt Toxin Cry 1Ac: Effects on Mating, Oviposition, Larval Development and Survival

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    Bt cotton plants are genetically engineered to produce insecticidal toxins from the Bacillus thuringiensis (Bt) Berliner (Bacillales: Bacillaceae) bacterium and target key lepidopteran pests. In all previous strains of pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) selected in the laboratory for resistance to insecticidal Cry1Ac toxin using an artificial diet containing the toxin, resistance to Cry1Ac and to Bt cotton is linked to three cadherin alleles (r1, r2, and r3). In contrast, the BG(4) pink bollworm strain was selected for resistance to Bt cotton by feeding larvae for four days in each of 42 generations on bolls of ‘NuCOTN33B®’ that expressed Cry1Ac toxin. After additional selection for eleven generations on Cry1Ac-incorporated diet, the susceptibility to Cry1Ac, fecundity, egg viability, and mating of this strain (Bt4R) was compared with the unselected Cry1Ac-susceptible parent strain. Some larvae of the Bt4R strain survived on diet containing ≥ 10 µg Cry1Ac per milliliter artificial diet, but none survived on transgenic cotton bolls. In contrast to strains selected exclusively on Cry1Ac diet, some survival of progeny of reciprocal moth crosses of Bt4R resistant and Bt-susceptible strains occurred on Cry1Ac-treated diet, suggesting differences in levels of dominance. The Bt4R resistant strain does not have the r1, r2, or r3 mutant cadherin genes as do all previous strains of pink bollworm selected on Cry1Ac-treated artificial diet. The combined results suggest a mechanism of resistance to Cry1Ac that is different from previously described cadherin mutations

    Incremental residential densification and urban spatial justice: The case of England between 2001 and 2011

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    Study of the relation between urban density and social equity has been based mostly upon comparative analysis at the city level. It therefore fails to address variations in intra-urban experience and sheds no light on the process of urban densification. Incremental residential development is particularly poorly recorded and under-researched, yet cumulatively it makes a substantial contribution to the supply of dwellings. The article presents a detailed examination of this form of development in England between 2001 and 2011, and considers its impact on urban spatial justice. We find that the incidence of soft residential densification was very uneven. It had disproportionately large effects on neighbourhoods that were already densely developed and that were characterised by lower income households with access to relatively little residential space. It thus contributed to an increase in the level of inequality in the distribution of residential space, increasing socio-spatial injustice
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