3,058 research outputs found
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,
Bt Cotton and farmer suicides in India: Reviewing the evidence
No full text"Suicides in general, including farmers' suicides, are a sad and complex phenomenon. Hence, their underlying causes need to be addressed within an equally complex societal framework. Here, we provide a specific case study on the potential link between technological choices and farmer suicides in India. Although officially recognized for having increased production and farmers' income, Bt cotton, genetically-modified, insect-resistant cotton, remains highly controversial in India. Among other allegations, it is accused of being the main reason for a resurgence of farmer suicides in India. In this paper, we provide a comprehensive review of evidence on Bt cotton and farmer suicides, taking into account information from published official and unofficial reports, peer-reviewed journal articles, published studies, media news clips, magazine articles, and radio broadcasts from India, Asia, and international sources from 2002 to 2007. The review is used to evaluate a set of hypotheses on whether or not there has been a resurgence of farmer suicides, and the potential relationship suicide may have with the use of Bt cotton. We first show that there is no evidence in available data of a “resurgence” of farmer suicides in India in the last five years. Second, we find that Bt cotton technology has been very effective overall in India. However, the context in which Bt cotton was introduced has generated disappointing results in some particular districts and seasons. Third, our analysis clearly shows that Bt cotton is neither a necessary nor a sufficient condition for the occurrence of farmer suicides. In contrast, many other factors have likely played a prominent role. Nevertheless, in specific regions and years, where Bt cotton may have indirectly contributed to farmer indebtedness, leading to suicides, its failure was mainly the result of the context or environment in which it was planted. We close the paper by proposing a conceptual framework for empirical applications linking the different agricultural and institutional factors that could have contributed to farmer suicides in recent years in certain districts of Central and Southern India." from authors' abstractCotton, Genetically modified crops, farmer suicides,
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,
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
Efeitos crônicos de milho transgênico (MON810) na dieta de Daphnia magna
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Recursos Genéticos VegetaisO cultivo de milho e o manejo de pragas associado têm grande impacto ecológico, e detritos pós-colheita constituem importante fonte de nutrientes em ecossistemas límnicos. O presente trabalho objetivou comparar os efeitos de uma variedade de milho transgênico (evento MON810) e sua linha isogênica na sobrevivência, crescimento e diversos parâmetros reprodutivos do organismo aquático não-alvo Daphnia magna, durante um experimento crônico de alimentação em laboratório utilizando folhas de milho. Detectou-se por immunoblotting a banda imunorreativa esperada do núcleo ativo de Cry1Ab truncada (69 kDa) e uma banda adicional inesperada de 35 kDa nas folhas de milho transgênico utilizadas no experimento. Daphnia magna alimentada com folhas de milho-Bt mostrou uma redução significativa em tamanho corporal e fecundidade em estádios tardios da vida, mas a sobrevivência não foi afetada. Adicionalmente, D. magna alimentada com folhas de milho-Bt produziram um maior número de ovos de dormência, uma resposta a condições estressantes. As diferenças observadas podem ter sido causadas por maiores custos metabólicos relacionados a uma pior qualidade nutricional do milho-Bt (efeitos pleiotrópicos derivados da transformação genética) e/ou a um efeito tóxico de Cry1Ab, que induziram em D. magna uma realocação de recursos para maior produção de ovos de dormência e fecundidade precoce, subseqüentemente acarretando uma redução no crescimento somático e na reprodução. O presente estudo provê evidencias de efeitos crônicos adversos de milho-Bt (MON810), e corrobora estudos anteriores que identificaram riscos de milho-Bt para organismos não-alvo e para o ambiente.Maize cultivation and associated pest management have great ecological impact and post-harvest detritus is a main source of organic nutrient income in freshwater ecosystems. The present study aimed to compare the effects of a transgenic maize variety (event MON810) and its isogenic line on survival, growth and several reproductive parameters in the aquatic non-target organism Daphnia magna, during a 42-day chronic laboratory feeding experiment using maize leaves. We detected the expected 69 kDa Cry1Ab immunoreactive band and an additional 35 kDa band in the transgenic maize material used for feed production. We found a significant reduction in body size and fecundity later in the lifespan of D. magna fed Bt-maize leaves, but survival was not affected. Additionally, Bt-maize fed D. magna produced a greater number of resting eggs, a response to stressful conditions. The observed effects may have been caused by greater metabolic costs related to a poorer nutritional quality of Bt-maize (pleiotropic effects derived from the genetic transformation) and/or a mild toxic effect of Cry1Ab, which induced a trade-off to allocate resources for production of resting eggs and early-life fecundity, subsequently causing a reduction in somatic growth and reproduction. The present study provides new evidence of chronic adverse effects of MON810 Bt-maize, and supports conclusions of studies that identified risks of transgenic Bt-maize to non-target organisms and the environment
Parametrizing W-weighted BT inverse to obtain the W-weighted q-BT inverse
No full text[EN] The core-EP and BT inverses for rectangular matrices were studied recently in the literature. The main aim of this paper is to unify both concepts by means of a new kind of generalized inverse called W-weighted q-BT inverse. We analyze its existence and uniqueness by considering an adequate matrix system. Basic properties and some interesting characterizations are proved for this new weighted generalized inverse. Also, we give a canonical form of the W-weighted q-BT inverse by means of the weighted core-EP decomposition.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The
first and third author are partially supported by Universidad Nacional de Río Cuarto (Grant PPI 18/C559) and
CONICET (Grant PIBAA 28720210100658CO). The second author was partially supported by Universidad
Nacional de La Pampa, Facultad de Ingeniería (Grant Resol. Nro. 135/19) and Ministerio de Economía,
Industria y Competitividad (Spain) [Grant Red de Excelencia RED2022-134176-T].Ferreyra, DE.; Thome, N.; Torigino, C. (2024). Parametrizing W-weighted BT inverse to obtain the W-weighted q-BT inverse. Revista de la Real Academia de Ciencias Exactas Físicas y Naturales Serie A Matemáticas. 118(3). https://doi.org/10.1007/s13398-024-01620-0S118
Production risk, farmer welfare, and Bt Corn in the Philippines
No full text© The Author(s) 2017. We determine the production risk effects and welfare implications of single-trait Bt corn adoption in the Philippines. We use a stochastic production function estimation approach that allows for examining the skewness effects of Bt within a damage abatement specification. Our results indicate that Bt corn has a statistically significant yield increasing, risk-increasing (i.e., variance-increasing) and downside risk-reducing (i.e., skewness-increasing) effects. Based on risk premium, certainty equivalent, and loss probability welfare measures, Bt corn farmers in the Philippines are better-off (in absolute terms) relative to non-Bt farmers given Bt corn\u27s dominant yield increasing effect and downside risk-reducing effect
Valuing Transgenic Cotton Technologies Using a Risk/Return Framework
No full textStochastic Efficiency with Respect to a Function (SERF) is used to rank transgenic cotton technology groups and place an upper and lower bound on their value. Yield and production data from replicated plot experiments are used to build cumulative distribution functions of returns for nontransgenic, Roundup Ready, Bollgard, and stacked gene cotton cultivars. Analysis of Arkansas data indicated that the stacked gene and Roundup Ready technologies would be preferred by a large number of risk neutral and risk averse producers as long as the costs of the technology and seed are below the lower bounds calculated in this manuscript.cotton, financial risk, market value, SERF, transgenic, Agribusiness, Crop Production/Industries, Risk and Uncertainty, Q12, Q16,
Impact of Violated High-Dose Refuge Assumptions on Evolution of Bt-Resistance
No full textTransgenic crops expressing Bacillus thuringiensis (Bt) toxins have been widely and successfully deployed for the control of target pests, while allowing a substantial reduction of insecticide use. The evolution of resistance (a heritable decrease in susceptibility to Bt toxins) can pose a threat to sustained control of target pests, but a high-dose refuge (HDR) management strategy has been key to delaying countervailing evolution of Bt resistance. The HDR strategy relies on the mating frequency between susceptible and resistant individuals, so either partial dominance of resistant alleles or non-random mating in the pest population itself could elevate the pace of resistance evolution. Using classic Wright-Fisher genetic models, we investigated the impact of deviations from standard refuge model assumptions on resistance evolution in the pest populations. We show that when Bt selection is strong, even deviations from random mating and/or strictly recessive resistance that are below the threshold of detection can yield dramatic increases in the pace of resistance evolution. Resistance evolution is hastened whenever the order of magnitude of model violations exceeds the initial frequency of resistant alleles. We also show that existence of a fitness cost for resistant individuals on the refuge crop cannot easily overcome the effect of violated HDR assumptions. We propose a parametrically explicit framework that enables both comparison of various field situations and model inference. Using this model, we propose novel empiric estimators of the pace of resistance evolution (and time to loss of control), whose simple calculation relies on the observed change in resistance allele frequency.Peer reviewe
- …
