Alves-Santos, F. M., Ramos, B., García-Sánchez, M. A., Eslava, A. P., and Díaz-Mínguez, J. M. 200... more Alves-Santos, F. M., Ramos, B., García-Sánchez, M. A., Eslava, A. P., and Díaz-Mínguez, J. M. 2002. A DNA-based procedure for in planta detection of Fusarium oxysporum f. sp. phaseoli. Phytopathology 92:237-244.
This paper analyzes the efficiency of a Portuguese public-owned hotel chain, Enatur. It applies d... more This paper analyzes the efficiency of a Portuguese public-owned hotel chain, Enatur. It applies data envelopment analysis (DEA) to estimate total factor productivity (TFP) change: while breaking it down into technical e~ciency and technological change. The bench.marking procedure used is an internal one, which compares hotels with each other. For the period 1999-2001, the hotels are ranked according to their total productivity change. It is concluded that some hotels experienced productivity growth, while others faced a decline. Some implications beneficial for managerial policies were drawn from this study. (JEL D24, L83, M21, 052)
Fusarium wilt is an endemic disease in El Barco de Avila (Castilla y León, west-central Spain), w... more Fusarium wilt is an endemic disease in El Barco de Avila (Castilla y León, west-central Spain), where high-quality common bean cultivars have been cultured for the last century. We used intergenic spacer (IGS) region polymorphism of ribosomal DNA, electrophoretic karyotype patterns, and vegetative compatibility and pathogenicity analyses to assess the genetic diversity within Fusarium oxysporum isolates recovered from common bean plants growing in fields around El Barco de Avila. Ninety-six vegetative compatibility groups (VCGs) were found among 128 isolates analyzed; most of these VCGs contained only a single isolate. The strains belonging to pathogenic VCGs and the most abundant nonpathogenic VCGs were further examined for polymorphisms in the IGS region and electrophoretic karyotype patterns. Isolates belonging to the same VCG exhibited the same IGS haplotype and very similar electrophoretic karyotype patterns. These findings are consistent with the hypothesis that VCGs represent clonal lineages that rarely, if ever, reproduce sexually. The F. oxysporum f. sp. phaseoli strains recovered had the same IGS haplotype and similar electrophoretic karyotype patterns, different from those found for F. oxysporum f. sp. phaseoli from the Americas, and were assigned to three new VCGs (VCGs 0166, 0167, and 0168). Based on our results, we do not consider the strains belonging to F. oxysporum f. sp. phaseoli to be a monophyletic group within F. oxysporum, as there is no correlation between pathogenicity and VCG, IGS restriction fragment length polymorphism, or electrophoretic karyotype.
The paper assesses the steady-state performance of a five-phase induction machine fed by a modifi... more The paper assesses the steady-state performance of a five-phase induction machine fed by a modified open loop constant volt/hertz (V/f) control method, which imposes a trapezoidal induction waveform in the air gap under varying load conditions. The trapezoidal air gap induction is achieved through the imposition of an appropriate combination of the third harmonic and fundamental stator voltages. This harmonic combination is determined from the steady-state model using a mathematical optimization procedure, which allows to obtain the optimal weighting factors for each harmonic component. The optimized reference voltages lead to a trapezoidal air gap induction, which allows a better iron utilization and higher output torque for the same rms stator current when compared to sinusoidal air gap induction. The resulting air gap induction is obtained from the induced voltage of a full pitch search coil placed in the air gap. The proposed control scheme was successfully simulated and implemented on a five-phase prototype machine running under different load conditions. Experimental and simulations results show an increase in the torque/ampere relationship for loads above 50% when compared to the conventional V/f method using only the fundamental current and air gap induction. A comparison between the simulation and experimental curves presents a very good agreement that confirms and validates the parameters and model used.
O objetivo deste artigo é relacionar as relações consumeiristas que ocorrem via internet a um par... more O objetivo deste artigo é relacionar as relações consumeiristas que ocorrem via internet a um paradigma relativamente novo de consumo: o consumo sustentável. Atualmente, e em virtude dos vários instrumentos que a internet oferece, os conceitos de fornecedor e consumidor usuais e descritos na legislação específica tornaram-se ultrapassados. Na rede, há ferramentas facilitadoras que tornam a relação de consumo "transeconômica", isto é, alguns consumidores não estão mais adquirindo produtos e serviços com fins de acumulação, como é tipicamente faziam, e sim, usam a internet para trocar ou comprar produtos ou mesmo serviços que estão sendo oferecidos por outros (fornecedores, mas também consumidores) e que, grande parte das vezesno caso dos produtos -, são usados. Isso faz com que bens que já existem circulem e não fiquem acumulados-refugados no ambiente. É o despertar de uma cultura consumeirista-sutentável. Palavras-chave: Consumidor. Internet. Ambiente. Sustentabilidade.
Alves-Santos, F. M., Ramos, B., García-Sánchez, M. A., Eslava, A. P., and Díaz-Mínguez, J. M. 200... more Alves-Santos, F. M., Ramos, B., García-Sánchez, M. A., Eslava, A. P., and Díaz-Mínguez, J. M. 2002. A DNA-based procedure for in planta detection of Fusarium oxysporum f. sp. phaseoli. Phytopathology 92:237-244.
This paper analyzes the efficiency of a Portuguese public-owned hotel chain, Enatur. It applies d... more This paper analyzes the efficiency of a Portuguese public-owned hotel chain, Enatur. It applies data envelopment analysis (DEA) to estimate total factor productivity (TFP) change: while breaking it down into technical e~ciency and technological change. The bench.marking procedure used is an internal one, which compares hotels with each other. For the period 1999-2001, the hotels are ranked according to their total productivity change. It is concluded that some hotels experienced productivity growth, while others faced a decline. Some implications beneficial for managerial policies were drawn from this study. (JEL D24, L83, M21, 052)
Fusarium wilt is an endemic disease in El Barco de Avila (Castilla y León, west-central Spain), w... more Fusarium wilt is an endemic disease in El Barco de Avila (Castilla y León, west-central Spain), where high-quality common bean cultivars have been cultured for the last century. We used intergenic spacer (IGS) region polymorphism of ribosomal DNA, electrophoretic karyotype patterns, and vegetative compatibility and pathogenicity analyses to assess the genetic diversity within Fusarium oxysporum isolates recovered from common bean plants growing in fields around El Barco de Avila. Ninety-six vegetative compatibility groups (VCGs) were found among 128 isolates analyzed; most of these VCGs contained only a single isolate. The strains belonging to pathogenic VCGs and the most abundant nonpathogenic VCGs were further examined for polymorphisms in the IGS region and electrophoretic karyotype patterns. Isolates belonging to the same VCG exhibited the same IGS haplotype and very similar electrophoretic karyotype patterns. These findings are consistent with the hypothesis that VCGs represent clonal lineages that rarely, if ever, reproduce sexually. The F. oxysporum f. sp. phaseoli strains recovered had the same IGS haplotype and similar electrophoretic karyotype patterns, different from those found for F. oxysporum f. sp. phaseoli from the Americas, and were assigned to three new VCGs (VCGs 0166, 0167, and 0168). Based on our results, we do not consider the strains belonging to F. oxysporum f. sp. phaseoli to be a monophyletic group within F. oxysporum, as there is no correlation between pathogenicity and VCG, IGS restriction fragment length polymorphism, or electrophoretic karyotype.
The paper assesses the steady-state performance of a five-phase induction machine fed by a modifi... more The paper assesses the steady-state performance of a five-phase induction machine fed by a modified open loop constant volt/hertz (V/f) control method, which imposes a trapezoidal induction waveform in the air gap under varying load conditions. The trapezoidal air gap induction is achieved through the imposition of an appropriate combination of the third harmonic and fundamental stator voltages. This harmonic combination is determined from the steady-state model using a mathematical optimization procedure, which allows to obtain the optimal weighting factors for each harmonic component. The optimized reference voltages lead to a trapezoidal air gap induction, which allows a better iron utilization and higher output torque for the same rms stator current when compared to sinusoidal air gap induction. The resulting air gap induction is obtained from the induced voltage of a full pitch search coil placed in the air gap. The proposed control scheme was successfully simulated and implemented on a five-phase prototype machine running under different load conditions. Experimental and simulations results show an increase in the torque/ampere relationship for loads above 50% when compared to the conventional V/f method using only the fundamental current and air gap induction. A comparison between the simulation and experimental curves presents a very good agreement that confirms and validates the parameters and model used.
O objetivo deste artigo é relacionar as relações consumeiristas que ocorrem via internet a um par... more O objetivo deste artigo é relacionar as relações consumeiristas que ocorrem via internet a um paradigma relativamente novo de consumo: o consumo sustentável. Atualmente, e em virtude dos vários instrumentos que a internet oferece, os conceitos de fornecedor e consumidor usuais e descritos na legislação específica tornaram-se ultrapassados. Na rede, há ferramentas facilitadoras que tornam a relação de consumo "transeconômica", isto é, alguns consumidores não estão mais adquirindo produtos e serviços com fins de acumulação, como é tipicamente faziam, e sim, usam a internet para trocar ou comprar produtos ou mesmo serviços que estão sendo oferecidos por outros (fornecedores, mas também consumidores) e que, grande parte das vezesno caso dos produtos -, são usados. Isso faz com que bens que já existem circulem e não fiquem acumulados-refugados no ambiente. É o despertar de uma cultura consumeirista-sutentável. Palavras-chave: Consumidor. Internet. Ambiente. Sustentabilidade.
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Papers by Fernando Alves