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排序方式: 共有337条查询结果,搜索用时 46 毫秒
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Joaquín Andaluz 《The Annals of Regional Science》2001,35(4):561-575
Using a simple characteristic space model of monopolistic competition with two interdependent markets, this paper analyses
the effects of the bilateral adoption of antidumping measures on the degree of product differentiation, as well as the relationships
with the type of product arrangement and the implications for welfare. Under an arrangement where each domestic firm competes
directly with two imported products (interleaved arrangement), the model reproduces some of the results that already exist
in the literature, where these have been obtained in an oligopolistic context. Through the characterisation of the symmetric
zero profit equilibrium, it is shown that under such an arrangement the degree of product variety is higher when governments
do not impose bilateral restrictions on prices. By contrast, under an arrangement where each half of the market is made-up
of products of the same nationality (split arrangement), the reciprocal imposition of antidumping legislation has no effect
on either the degree of product variety or on social welfare.
Received: March 2000/Accepted: May 2001 相似文献
35.
Sánchez-García JA Ortega A Barceló-Santana FH Palacios-Alquisira J 《International journal of molecular sciences》2010,11(10):3906-3921
Maxillofacial prostheses is a dental medicine specialty aimed at restoring anatomical facial defects caused by cancer, trauma or congenital malformations through an artificial device, which is commonly attached to the skin with the help of an adhesive. The purpose of our research was to develop a pressure-sensitive adhesive (PSA) based on acrylic monomers, characterizing and determining its drying kinetics, that is to say the time it takes to lose 50 to 90% of its moisture. The adhesive synthesis was realized by means of emulsion polymerization; the composition of formulations was: (AA-MMA-EA) and (AA-MMA-2EHA) with different molar ratios. The formulation based on (AA-MMA-2EHA) with 50 w% of solids, presented good adhesive properties such as tack, bond strength, and short drying time. We propose this formulation as a PSA, because it offers an alternative for systemically compromised patients, by less irritation compared to organic solvent-based adhesives. 相似文献
36.
Navas J Ortiz S López P López V Martínez-Suárez JV 《Journal of food protection》2007,70(12):2851-2854
This study aimed to evaluate the effect of different enrichment procedures on the detection of Listeria monocytogenes in food, by a comparison of subculture onto chromogenic agar with real-time PCR. Two different culture media, the primary and secondary enrichment broths of the U.S. Food Safety and Inspection Service (FSIS) method used for PCR detection of L. monocytogenes, were compared for the primary enrichment of retail ground chicken samples. L. monocytogenes was detected after the completion of each enrichment procedure in 63% (complete FSIS procedure) and 60% (plain FSIS secondary enrichment broth incubated for 48 h) of the samples by both culture and PCR, whereas a combination of the results for the two enrichment procedures revealed 86% of the samples to be positive. Most of the samples analyzed contained a mixture of lineage I and II strains, and their ratio varied for each enrichment procedure. This mixture could have a significant effect on the result of detection of L. monocytogenes for each individual sample, explaining the increase in positive samples when the results of the two enrichment procedures were combined. The use of different isolation procedures can affect the specific samples identified as positive and the specific strains isolated. 相似文献
37.
Lessening polygalacturonase activity in a commercial enzyme preparation by exposure to pulsed electric fields 总被引:1,自引:0,他引:1
Joaquín?Giner Vicente?Gimeno Montserrat?Palomes Gustavo?V.?Barbosa-Cánovas Olga?MartínEmail author 《European Food Research and Technology》2003,217(1):43-48
The effect of high-intensity pulsed electric field (HIPEF) treatments on polygalacturonase (PG) activity in an aqueous solution of a commercial enzyme preparation was evaluated. HIPEF treatments reduced PG activity notably. Exponentially decaying pulses of 40 and 160 µs generated by a laboratory scale device were applied in a batch processing and bipolar mode. Electric fields ranged from 5.18 to 19.39 kV/cm. The number of pulses ranged up to 400. Temperature was always below 25 °C. Maximum inactivation of PG activity (98%) required 32.4 ms HIPEF treatment at 10.28 kV/cm. PG activity depleted exponentially because of HIPEF treatments. The first order rate constants ranged from 32 to 590 µs -1 and increased exponentially with electric field intensity. PG activity decreased exponentially with input electric energy density. 相似文献
38.
Antioxidant Activity of Added Phenolic Compounds in Freeze-Dried Microencapsulated Sunflower Oil 总被引:1,自引:0,他引:1
Joaquín Velasco Francisca Holgado Carmen Dobarganes Gloria Márquez-Ruiz 《Journal of the American Oil Chemists' Society》2009,86(5):445-452
This study was aimed at evaluating the effectiveness of phenolic antioxidants with a similar structure but having a different
polarity in dried microencapsulated sunflower oil. The antioxidants tested were, on one hand, α-tocopherol and its water soluble
analogue, Trolox, and on the other, gallic acid and its ester derivatives, propyl gallate and dodecyl gallate. At a moderate
temperature (40 °C), the samples were oxidized under accelerated conditions by using Cu(II) as an oxidation catalyst. The
progress of oxidation was followed up over time in the free and encapsulated oil fractions. The peroxide value, the total
content of polymers and, when appropriate, the content of α-tocopherol were determined. Quantitative analysis of the total
fraction of the non-volatile oxidation products and their distribution in oligomers, dimers and monomers was applied to samples
to obtain a complete evaluation of oxidation. Finally, as a complementary measure, the antioxidants were also assessed by
direct application of the Rancimat test at 100 °C on the dried microencapsulated oil samples. Results showed that the antioxidants
of lower polarity in each series, i.e. tocopherol and dodecyl gallate, were to a great extent the most protective antioxidants.
The results obtained by the Rancimat test were consistent with those found during oxidation at moderate temperature. Furthermore,
the addition of Cu(II) reduced proportionally the oxidative stability index of the dried microencapsulated samples. 相似文献
39.
Louis de Grange Enrique Fernández Joaquín de Cea Magdalena Irrazábal 《Networks and Spatial Economics》2010,10(4):551-578
A methodology is proposed for estimating a combined transportation model that accommodates spatial aggregation. It employs
maximum likelihood estimation using a joint probability function that includes destination and mode choice simultaneously.
The main contribution of the paper is the incorporation of a spatial aggregation strategy to validate the method when the
survey data are insufficient. By aggregating small zones into larger districts, estimation of the trip distribution parameters
can be achieved with limited data, while mode choice continues to be estimated using disaggregated data. Our results demonstrate
that including trip distribution in the travel decision induces variations in the utility function parameter estimators obtained
for the different travel modes when only mode choice is estimated. The methodology thus corrects omission bias. 相似文献
40.