2,483 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,
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,
Efficient calculation of empirical p-values for genome wide linkage analysis through weighted permutation
No full textThe 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
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
Coaching Initiative for Beginning Teachers (BT): Lessons Learned from One District’s BT Support Program
No full textInstructional coaching is a way to support classroom teachers in their efforts to provide high quality instruction across academic content areas. Because of beginner teachers’ needs for extra support, many districts are now embracing instructional coaches to provide specific pedagogical feedback to their beginning teachers via job-embedded, individualized, and sustained professional guidance. This initial, exploratory study employed mixed methods to gain both qualitative and quantitative insights into one district’s Beginning Teacher Support Program in general and Coaching Program in particular. Results indicate that, without a laser-like focus on instruction, the impact of coaching on student achievement and teacher retention is limited. Sharing resources, providing emotional support and helping new teachers manage stress is important but discussing instructional strategies, observing and discussing lessons, and modeling instruction is critically more important
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
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