5,582 research outputs found
ESTIMATING THE VALUE OF BT CORN: A MULTI-STATE COMPARISON
No full textBt corn offers a powerful tool to control European corn borers and some other pests. Because pest infestations and farming practices differ across the Corn Belt, economic benefits also differ. This research estimates the value of Bt corn across the Corn Belt. Results identify areas where Bt adoption is economically justified.Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,
The Role of Coordination and Cooperation for Bt-maize cultivation in Brandenburg, Germany
No full textSince 2006, several varieties of transgenic Bt-maize are approved for commercial cultivation in Germany. The German regulatory framework for growing these crops comprises ex-ante regulations as well as ex-post liability rules to protect conventional and organic farming from possible negative side effects of transgenic plants and to ensure co-existence. Public regulation is also suspected to impose additional costs to those farmers who intend to plant Bt-maize. We address the question how Bt-maize growing farmers perceive the additional costs of regulation and whether coordination or cooperation takes place in order to diminish these costs. In 2006, we carried out a case study in the Oderbruch region (Brandenburg, Germany) comprising eight Bt-maize growing farmers and six adjacent neighbours. The predominantly large farms chose intrafarm coordination to manage the construction of buffer zones within their own fields and to avoid the planting of Bt-maize close to their neighbours. Inter-farm coordination or cooperation with adjacent farmers was not regarded necessary to achieve co-existence.Coordination, Cooperation, Bt-maize, Crop Production/Industries,
Effect of pyramiding Bt and CpTI genes on resistance of cotton to Helicoverpa armigera (Lepidoptera: Noctuidae) under laboratory and field conditions
No full textTransgenic cotton (Gossypium hirsutum L.) varieties, adapted to China, have been bred that express two genes for resistance to insects. the Cry1Ac gene from Bacillus thuringiensis (Berliner) (Bt), and a trypsin inhibitor gene from cowpea (CpTI). Effectiveness of the double gene modification in conferring resistance to cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), was studied in laboratory and field experiments. In each experiment, performance of Bt+CpTI cotton was compared with Bt cotton and to a conventional nontransgenic variety. Larval survival was lower on both types of transgenic variety, compared with the conventional cotton. Survival of first-, second-, and third-stage larvae was lower on Bt+CpTI cotton than on Bt cotton. Plant structures differed in level of resistance, and these differences were similar on Bt and Bt+CpTI cotton. Likewise, seasonal trends in level of resistance in different plant structures were similar in Bt and Bt+CpTI cotton. Both types of transgenic cotton interfered with development of sixth-stage larvae to adults, and no offspring was produced by H. armigera that fed on Bt or Bt+CpTI cotton from the sixth stage onward. First-, second-, and third-stage larvae spent significantly less time feeding on transgenic cotton than on conventional cotton, and the reduction in feeding time was significantly greater on Bt+CpTI cotton than on Bt cotton. Food conversion efficiency was lower on transgenic varieties than on conventional cotton, but there was no significant difference between Bt and Bt+CpTI cotton. In 3-yr field experimentation, bollworm densities were greatly suppressed on transgenic as compared with conventional cotton, but no significant differences between Bt and Bt+CpTI cotton were found. Overall, the results from laboratory work indicate that introduction of the CpTI gene in Bt cotton raises some components of resistance in cotton against H. armigera, but enhanced control of H. armigera under field conditions, due to expression of the CpTI gene, was not demonstrate
The Diffusion of Bt Cotton and the Economic Impact on Producers
No full textThe objective is to present the economic impact of producers adopting Bt cotton and the rapid diffusion on the main producing countries: USA, China and India. The existing literature about this type of transgenic crop has been revised and the results of different research are presented. Bt cotton varieties have been quickly adopted by the countries in this study. Data show that this technology helps reduce production losses and significantly decrease the use of pesticides, thus saving their cost and the associated labour cost. But the total cost reduction is weak due to the high prices of the seeds incorporating this technology.Innovation diffusion, Bt cotton, Crop Production/Industries,
Experimental study on the effects of visualized functionally abstracted information on process control tasks
No full textTwo distinct design problems of information display for process control are information content representation and visual form design. Regarding information content, we experimentally showed the effectiveness of functionally abstracted information without the benefits of sophisticated graphical presentation in various task situations. However, since it is obvious that the effects of the information display are also influenced by display formats (i.e., visual forms) as well as the information content, further research was required to investigate the effectiveness of visualized functionally abstracted information. For this purpose, this study conducted an experiment in complex process control tasks (operation and fault diagnosis). The experimental purposes were to confirm the effectiveness of the functionally abstracted information visualized with emergent features or peculiar geometric forms and to examine the additional effects of the visualization on task performance. The results showed that functionally abstracted information presented with sophisticated visual forms helped operators perform process control tasks in more efficient and safe way. The results also indicated the importance of explicit visualization of goal-means relation between higher and lower abstraction levels. Lastly, this study proposed a framework for designing visual forms for process control display. (c) 2007 Elsevier Ltd. All rights reserved
Technology integration and seed market organization: The case of GM Cotton diffusion in Jiangsu Province (China)
No full textPlusieurs articles ont contribué à faire passer l'idée selon laquelle les avantages spécifiques du coton-Bt sont responsables du succès de la diffusion du coton génétiquement modifié en Chine. L'efficience du coton-Bt varie cependant entre les régions cotonnières du pays. Dans la Province du Jiangsu, le long de la Vallée du Fleuve Yangtze, il n'y a pas d'augementation de rendement, la réduction de l'utilisation des insecticides est faible et il n'y a pas de gain de rendement associé spécifiquement à l'utilisation du coton-Bt. L'utilisation du coton-Bt est néanmoins quasi générale. Une approche plus globale, en ne se focalisant pas seulement sur les effets spécifiques du coton-Bt, permet de comprendre ce paradoxe apparent. Dans la Province du Jiangsu, la diffusion du coton-Bt a bénéficié de son intégration dans les cultivars hybrides qui sont parfaitement adaptés à la technique de transplantation. Ce cas chinois indique que l'évaluation de l'utilisation du coton-Bt dans les autres pays devrait considérer le degré de compatibilité avec les techniques existantes de production.En Chine, la commercialisation du coton-Bt a induit la modernisation du marché des semences . Les paysans ont d'abord bénéficié de ce processus avant de pâtir des effets négatifs des stratégies de commercialisation des semences au prix élevé. Si le coton-Bt doit donner plus aux paysans qu'il ne leur retire, une certaine regulation du marché des semences est souhaitable.Agriculture, Biotechnologies, Industrie des semences, variétés, concurrence, marketing des semences
The practice of access pricing : telecommunications in the United Kingdom
No full textTelecommunications was the first network utility to be privatized in the United Kingdom. Drawing on 15 years'experience and discussion in the field, the author shows the economic principles of regulation in general and access pricing in particular that have been implemented. British Telecommunications (BT), formed as a public enterprise in 1980-81, was privatized in 1984. Since then the approaches to regulation have changed in three broad periods: the duoply, the transition to competition, and the recently introduced normalization phase. Dealing with each period, the author focuses on how the actual implementation of access charges are determined, at the same time providing background needed on regulatory intervention generally. Rather than follow the model of competition for a common infrastructure, Oftel [the Office of Telecommunications, the regulatory agency]has encouraged competition between alternative networks, which benefits customers but involves duplication of fixed costs. As a result of Oftel's approach, customers have seen their bills reduced 50 percent in real terms since privatization. It is difficult to know how much to attribute this remarkable result to technological progress (BT halved its workforce in the same period), to regulatory intervention (Oftel set string caps until 1997), or to competition (there are hundreds of players in the market). The author contends more weight should probably be given to the first two. Entrants have not achieved big market shares, if one considers the asymmetric regulation that has been in place for more than a decade. Indirectly, at least, competition benefited consumers by applying discipline to BT's behavior. Oftel's approach was interventionist until 1997, when it began trying to normalize the industry, as authority overseeing competition. The odds on complete deregulation are slight, and some controls on industry will remain. In the longer term, Oftel should especially monitor anticompetitive practices and collusive behavior among the bigger players (BT, CWC, and cellulator operators), The United Kingdom's interconnection experience demonstrates the complexity of the problem and its relationship to other topics, such as tariff rebalancing, access deficit, and universal service. Although a bit ad hoc, the recent incentive regulation, with a network cap based on proper accounting procedures and engineering models, may represent the best practice available today in the telecommunications industry, says the author.Public Sector Economics&Finance,Decentralization,Knowledge Economy,Economic Theory&Research,Payment Systems&Infrastructure,Public Sector Economics&Finance,Education for the Knowledge Economy,Knowledge Economy,Economic Theory&Research,ICT Policy and Strategies
<i>N</i>‑TFA-Gly-Bt-Based Stereoselective Synthesis of Substituted 3‑Amino Tetrahydro‑2<i>H</i>‑pyran-2-ones via an Organocatalyzed Cascade Process
No full textChiral-substituted
3-amino tetrahydro-2H-pyran-2-ones
were prepared in excellent enantioselectivities (up to 99% ee) via
an organo-catalyzed cascade procedure with N-TFA-Gly-Bt
and α,β-unsaturated aldehydes as the substrates. The corresponding
tetrahydro-2H-pyran-2-ones can be used for further
synthetic transformations that furnish chiral-substituted 3-aminopiperidin-2-ones
with high levels of stereoselectivity
<i>N</i>‑TFA-Gly-Bt-Based Stereoselective Synthesis of Substituted 3‑Amino Tetrahydro‑2<i>H</i>‑pyran-2-ones via an Organocatalyzed Cascade Process
No full textChiral-substituted
3-amino tetrahydro-2H-pyran-2-ones
were prepared in excellent enantioselectivities (up to 99% ee) via
an organo-catalyzed cascade procedure with N-TFA-Gly-Bt
and α,β-unsaturated aldehydes as the substrates. The corresponding
tetrahydro-2H-pyran-2-ones can be used for further
synthetic transformations that furnish chiral-substituted 3-aminopiperidin-2-ones
with high levels of stereoselectivity
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