An application of neural networks in microeconomics: input-output mapping in a power generation subsector of the US electricity industry

The use of the artificial neural networks in economics and business goes back to 1950s, while the major bulk of the applications have been developed in more recent years. Reviewing this literature indicates that the field of business benefits from the neural networks in a wide spectrum from prediction to classification, as most of the applications in economics primarily focus on the predictive power of the neural networks. Time series analysis and forecasting, econometrics, macroeconomics constitute the main areas of economics, where there is an increasing interest in application of neural networks. Although their promising contributions to the area of microeconomics, the applications of neural networks in this area are limited in number. This study provides a microeconomic application of an artificial neural network by input-output mapping for 82 US major investor-owned electric utilities using fossil-fuel fired steam electric power generation for the year 1996. We construct a multilayer feed-forward neural network (MFNN) with back-ropagation to represent the relationship between a set of inputs and an electricity production as an output. The network is trained and tested by using approximately 80 percent and 20 percent of the data, respectively. The network is trained with 97% accuracy and performance of the network in testing is 96%. Therefore, this network can be used in calculating electricity output for the given inputs in this subsector of the US electricity market, and these estimations can be employed in policy design and plannin

In vitro and in vivo performance of universal adhesive systems on dentin with different etching strategies

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESThe new generation of adhesive systems, called as "universal adhesives" or "multi-mode", are adhesives which can be used in both self-etch (SE) or etch-and-rinse (ER) strategies. Two studies related to these materials are presented. The aim of the first paper was to evaluate immediate and 1 year bond strength of universal adhesives to sound and cariesaffected dentin, using both SE and ER strategies. The universal adhesives tested were: Scotchbond Universal, All - Bond Universal, Prime & Bond Elect. As controls were used the adhesives Adper Single Bond 2 and Clearfil SE Bond, for ER and SE strategies respectively. They were applied following the manufacturers' instructions and a composite resin (Z250) block was built on dentin. Caries-affected dentin was artificially obtained by pH cycling for 14 days. Stick-shaped specimens were obtained (0.8 mm²) and submitted to microtensile test immediately or after 1 year of water storage. The data obtained in MPa were submitted to 3- way ANOVA for repeated measures and Post-hoc Tukey's test (α = 5%). Significant crossinteraction among the three factors (material x strategy x time) was found on both sound (p=0.002) and caries-affected dentin (p=0.009) analyses. Pronounced degradation was observed for all groups after one year on caries-affected dentin. In sound dentin, only the universal adhesives used in SE mode and the control adhesives were able to maintain bond stability after 1 year. Thus, the universal adhesives were not able to maintain bond stability in caries-affected dentin. On sound dentin, the self-etching strategy seems to be the best approach to maintain bond stability. The second paper is a randomized clinical trial that aimed to evaluate the longevity of non-carious cervical lesions restorations (NCCL) using two universal adhesive systems: Prime&Bond Elect (PB) and Scotchbond Universal (SBU) under different application strategies (ER and SE). Fifty-four participants who fit into the eligibility criteria (at least 1 tooth with LCNC, caries-free, non-retentive, with a depth greater than 1mm) were selected. Individuals who presented teeth without pulp vitality, without presence of an antagonistic tooth, previous restoration report, orthodontic treatment, smokers, patients with severe bruxism, extremely poor oral hygiene and / or with severe or chronic periodontal disease were excluded. Two hundred and eleven teeth were restored according to the experimental groups: PB-ER, PB-SE, SBU-ER and SBU-SE, with composite resin, by 2 previously trained operators. A single trained and calibrated examiner evaluated restorations after 1 week (baseline) and 6 months, using the modified USPHS and FDI evaluation criteria. The obtained data were tabulated and submitted to Kruskal-Wallis and Mann-Whitney tests to compare the failures among experimental groups. Statistical difference was found between the groups in regard to failures for both evaluation criteria. The PB-SE group had significantly more failures than the other experimental groups. Thus, the clinical performance of Prime & Bond Elect was dependent on the application strategy, and a poorer performance was found for the self-etch strategy.A última geração de sistemas adesivos, os “adesivos universais” ou “multi-modo”, são adesivos que podem ser utilizados tanto na estratégia autocondicionante (SE) como com condicionamento ácido prévio (ER). No presente trabalho são apresentados dois artigos acerca destes materiais. O objetivo do primeiro artigo foi avaliar a resistência de união imediata e após 1 ano de adesivos universais em dentina hígida e afetada, usando duas estratégias de condicionamento – ER e SE. Os adesivos universais testados foram: Scotchbond Universal, All-Bond Universal e Prime&Bond Elect. Os controles foram os adesivos Adper Single Bond 2 e Clearfil SE Bond, para as estratégias ER e SE respectivamente. Foram aplicados seguindo as recomendações dos fabricantes e um bloco de resina composta (Z250) foi construído sobre a dentina. A dentina afetada foi obtida artificialmente através de ciclagem de pH por 14 dias. Espécimes em forma de palitos foram obtidos (0,8 mm²) para serem submetidos ao teste de microtração imediatamente ou após 1 ano de armazenamento. Os dados obtidos em MPa foram analisados por ANOVA de 3 fatores para dados repetidos e post-hoc Tukey (α= 5%). Significativa interação entre os fatores (material x estratégia x tempo) foi encontrada tanto para dentina hígida (p=0,002) como para dentina afetada (p=0,009). Pronunciada degradação foi observada para todos os grupos após um ano em dentina afetada. Em dentina hígida, somente os adesivos universais foram capazes de manter estabilidade da união após 1 ano somente no modo autocondicionante assim como os adesivos controle. Em dentina afetada, os adesivos universais não foram capazes de manter a estabilidade de união. Em dentina hígida, a estratégia autocondicionante parece ser a melhor maneira para manter a estabilidade da união. O segundo artigo é um estudo clínico randomizado que teve como o objetivo avaliar a longevidade de restaurações de lesões cervicais não-cariosas (LCNC), utilizando dois sistemas adesivos universais: Prime&Bond Elect (PB) e Scotchbond Universal (SBU) sob diferentes estratégias de aplicação (ER e SE). Foram selecionados 54 participantes conforme critérios de eligibilidade (possuir no mínimo 1 dente com LCNC, livre de cárie, nãoretentiva, profundidade maior que 1mm). Foram excluídos os indivíduos que apresentaram dentes sem vitalidade pulpar, sem presença de dente antagonista, relato de restauração prévia, em tratamento ortodôntico, fumantes, portadores de bruxismo severo, higiene oral extremamente pobre e/ou com doença periodontal severa ou crônica. Duzentos e onze dentes foram restaurados conforme os grupos experimentais: PB-ER, PB-SE, SBU-ER e SBU-SE, com resina composta, por 2 operadores previamente treinados. As restaurações foram avaliadas por um examinador treinado e calibrado após 1 semana (baseline) e 6, meses, utilizando os critérios de avaliação USPHS modficado e FDI. Os dados obtidos foram submetidos aos testes de Kruskal-Wallis e Mann-Whitney para comparar as falhas entre os grupos experimentais. Diferença estatística foi encontrada entre os grupos em relação as falhas para os dois critérios de avaliação. O grupo PBSE apresentou significativamente mais falhas que os outros grupos experimentais. Dessa forma, a performance clínica do Prime & Bond Elect foi dependente da estratégia de aplicação, sendo que piores resultados foram encontrados para o modo autocondicionante

Knowledge at work: learning and transferring expert reasoning through storytelling

There is plenty of evidence in many fields of knowledge that storytelling is a bona fide human activity for problem-solving. We believe that a storytelling model for problem-solving can be constructed to organize this discourse. To that end, we carried out a qualitative study using the Grounded Theory tradition to build such a model always mindful of the plethora of findings related to storytelling in the professional literature. Our study finds that stories in problem-solving abound. Building on the existing literature and the results of our study, we develop a model that can serve as a foundation for more storytelling research and discussio

Investment in a methane digester: an application of capital budgeting and real options

Methane digesters may offer dairy producers a way to lower production costs by becoming self-sufficient in electricity production. In addition, the technology may offer additional income through surplus electricity sales and fertilizer and bedding savings as well. However, the typical methane digester is a large and irreversible capital investment characterized by value uncertainty. Analyzed in a real option framework, the theory suggests a potential explanation for why producers in states like Pennsylvania require significant grant funding to adopt the technology, namely, as monetary compensation for the uncertainty in the value of the completed project. The study presents an empirical applicatio

An entropy approach to size and variance heterogeneity

In this paper, we investigate the effect of bank size differences on cost efficiency heterogeneity using a heteroskedastic stochastic frontier model. This model is implemented by using an information theoretic maximum entropy approach. We explicitly model both bank size and variance heterogeneity simultaneously. We find that non-performing loans, federal insurance premium, legal expenses and director fees drive bank inefficiency as the bank becomes larger. Moral hazard, bank management and a “too big to fail” doctrine are likely explanations for the results from this study. Keywords Commercial Banks . Heteroskedasticity . Cost Frontier . Maximum Entrop

Dynamic Productivity Growth in the Spanish Meat Industry

This paper develops a dynamic Luenberger productivity growth indicator and decomposes it to identify the contributions of technical change, technical efficiency change and scale change. The Luenberger productivity growth indicator is estimated using Data Envelopment Analysis. The empirical application focuses on panel data of Spanish meat processing firms over the period 2000-2010. The dynamic Luenberger indicator shows productivity decrease of on average -0.003 in the period under investigation, with technical regress being the main driver of change, despite technical and scale efficiency growth

Designing the emerging EU pesticide policy: A literature review

A European Union (EU) wide pesticide tax scheme is among the future plans of EUpolicy makers. This study examines the information needs for applying an optimal pesticidepolicy framework at the EU level. Damage control specification studies, empirical results from pesticide demand elasticity, issues on pesticide risk valuation and uncertainty, and knowledge on the indirect effects of pesticides in relation to current pesticidepolicies are analysed. Knowledge gaps based on reviewing this information are identified and an illustration is provided of the direction future pesticidepolicies should take

Assessing the Impact of Changing Economic Environment on Productivity Growth: The Case of the Spanish Dairy Processing Industry

This article analyzes the productivity growth of the Spanish dairy processing industry from 1996 till 2011, which concerns the period of increased EU regulation regarding food safety as well as economic crisis. Data envelopment analysis is used to compute the Malmquist index and its components. The results suggest that productivity on average declined during the period under investigation. The decomposition of the Malmquist index finds that technical regress contributed to productivity decline despite improvements in technical and scale efficiencies. Our results also suggest that food safety regulations did not have a negative impact on productivity growth. Technical change and scale efficiency change made significant negative contributions to productivity growth in the period under crisis, whereas firms significantly improved their technical efficiency in that period

Analyzing the impact of investment spikes on dynamic productivity growth

Firm-level data usually show that a large portion of firm-level investment takes place in a few investment episodes. This paper assesses productivity growth and its components in production framework that accounts for the dynamics of capital adjustment and relates this to investment spikes using firm-level data of the Spanish meat processing industry over the period 2000-2010. Using the method of impulse responses by local projections, it is shown that investment spikes produce a significant productivity change loss of 0.7% in the first year after the spike. The worsening of technology is the main cause of the reduction of productivity growth in the first year. Technology then improves in the fifth year as a result of investment spike, resulting in the U-shape pattern of relationship. Scale inefficiency significantly improves by 0.4% and 0.5% in the first and second year after the spike has occurred, respectively. All these effects, however, largely depend on the firms' size. In particular, it is shown that the loss of technology in the first year mainly pertains to smallest firms, while larger firms experience a negative impact on the contribution of technical inefficiency change to productivity growth