427 research outputs found
Revisiting Rose's common currency debate
The main objective of this research is to revisit the estimation of the effect of a common currency on international trade by applying the new methodology proposed by Helpman, Melitz and Rubistein (2008) and incorporating tourism to the theoretical framework. Rose (2000) estimates an empirical model of bilateral trade, finding a significant coefficient for a currency union variable of 1.2, suggesting an effect of currency unions on trade of over a 200%. Rose (2000)’s finding did not receive full acceptance and further research was consequently devoted to find reasons of such high effect. This still remains as a major puzzle in the International Economics. Rose and Van Wincoop (2001) hold that there may still be some omitted factors that drives countries to both participate in currency unions and trade more. In this research a gravity equation for trade is estimated controlling by international tourism.Common currency, tourism, gravity equation
On the impact of exchange rate regimes on tourism
The main objective of this paper is to analyze the effect of the exchange rate arrangements on international tourism. The ambiguity of literature about the effect of exchange rate volatility contrasts with the magnitude of the impact of a common currency on trade. On the basis of a gravity equation we estimate a moderate effect of a currency union on tourism of almost 12%. Furthermore, we estimate a gravity equation for international trade, obtaining that the common currency effect on trade is reduced when tourism is introduced as a regressor. This suggests that tourism flows may contribute to explain the excessive magnitude of the estimated effect of a common currency on trade in this literature. Finally, we analyze the impact of several de facto exchange rate arrangements on tourism, finding that less flexible exchange rates promotes tourism flows.Tourism, Exchange Rate Regime, Common Currency
Laboratorio Atlántico de Turismo: competitividad, innovación y gobernanza turística en Canarias
Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu
Kilo-instruction processors: overcoming the memory wall
Historically, advances in integrated circuit technology have driven improvements in processor microarchitecture and led to todays microprocessors with sophisticated pipelines operating at very high clock frequencies. However, performance improvements achievable by high-frequency microprocessors have become seriously limited by main-memory access latencies because main-memory speeds have improved at a much slower pace than microprocessor speeds. Its crucial to deal with this performance disparity, commonly known as the memory wall, to enable future high-frequency microprocessors to achieve their performance potential. To overcome the memory wall, we propose kilo-instruction processors-superscalar processors that can maintain a thousand or more simultaneous in-flight instructions. Doing so means designing key hardware structures so that the processor can satisfy the high resource requirements without significantly decreasing processor efficiency or increasing energy consumption.Peer ReviewedPostprint (published version
Aristolochia rzedowskiana (Aristolochiaceae), una especie nueva para la subsección Pentandrae del estado de Jalisco, México
Aristolochia rzedowskiana Santana-Michel & Guzmán-Hernández is described as a new species from a locality near San Sebastián del Oeste and Puerto Vallarta in the State of Jalisco, Mexico; it belongs toAristolochia sect. Gymnolobus subsect. Pentandrae. This species inhabits tropical subdeciduous forests and oak woods and can be identified by its perianth limb which is reddish, cordate-lanceolate, reflexed or straight, obtuse or attenuate towards the apex, with a papillose-reticulate surface and pale yellowish throat with dark spots. Its morphological characters relate it to Aristolochia variifolia, A. karwinskii and A. manantlanensis.Aristolochia rzedowskiana Santana-Michel & Guzmán-Hernández es descrita como especie nueva de una localidad cercana a San Sebastián del Oeste y Puerto Vallarta, en el estado de Jalisco, México; pertenece a Aristolochia sect. Gymnolobus subsect. Pentandrae. Esta planta habita en bosques tropicales subcaducifolios y encinares; se puede identificar por su limbo del perianto de color rojizo, cordado-lanceolado, reflexo o recto, obtuso o atenuado hacia el ápice, superficie del limbo papiloso-reticulada, garganta pálido-amarillenta con puntos obscuros. Por sus caracteres morfológicos se relaciona con Aristolochia variifolia, A. karwinskii y A. manantlanensis
Aristolochia emiliae (Aristolochiaceae: Subsección Pentandrae), una especie nueva de la costa de Jalisco, México
Aristolochia emiliae sp. nov., found in tropical deciduous forest in the Estación de Investigación, Experimentación y Difusión “Chamela”, municipality of La Huerta, Jalisco, Mexico, is described and illustrated. The geniculate flowers are less than 3 cm long with uncinate hairs on the orbicular calyx limb. The basal lobes of the trilobate leaves are anchor-shaped, a unique characteristic among the Mexican species in the Pentandrae subsection of Aristolochia.Se describe e ilustra a Aristolochia emiliae, procedente de la Estación de Investigación, Experimentación y Difusión “Chamela” en el municipio de La Huerta, Jalisco. La planta crece en el bosque tropical caducifolio. Se caracteriza por presentar flores geniculadas menores de 3 cm de largo, limbo del cáliz orbicular con pelos uncinados, hojas trilobadas con los lóbulos basales ancoriformes; esta última característica es única en las especies mexicanas de la subsección Pentandrae
On the problem of evaluating the performance of multiprogrammed workloads
Multithreaded architectures are becoming more and more popular. In order to evaluate their behavior, several methodologies and metrics have been proposed. A methodology defines when the measurements for a given workload execution are taken. A metric combines those measurements to obtain a final evaluation result. However, since current evaluation methodologies do not provide representative measurements for these metrics, the analysis and evaluation of novel ideas could be either unfair or misleading. Given the potential impact of multithreaded architectures on current and future processor designs, it is crucial to develop an accurate evaluation methodology for them. This paper presents FAME, a new evaluation methodology aimed to fairly measure the performance of multithreaded processors executing multiprogrammed workloads. FAME reexecutes all programs in the workload until all of them are fairly represented in the final measurements taken. We compare FAME with previously used methodologies showing that it provides more accurate measurements, becoming an ideal evaluation methodology to analyze proposals for multithreaded architectures.Peer ReviewedPostprint (published version
The component of Carica papaya seed toxic to A-aegypti and the identification of tegupain, the enzyme that generates it
As Aedes aegypti transmits the etiologic agents of both yellow and dengue fever; vector control is considered essential to minimise their incidence. the aim of this work was to identify the component of Carica papaya seed toxic to A. aegypti, and the identification of tegupain, the enzyme that generates it. Aqueous extracts (1%, w/v) of the seed tegument and cotyledon of C. papaya are not larvicidal isolately. However, a mixture of 17 mu g mL(-1) tegument extract and 27 mu g mL(-1) cotyledon extract caused 100% larval mortality in a bioassay. the mixture was no longer larvicidal after the tegument extract was pre-treated at 100 degrees C for 10 min. the enzyme tegupain efficiently hydrolysed the substrate Z-Phe-Arg-pNan (K-m 58.8 mu M, K-cat 28020 s(-1), K-cat/K-m 5 x 10(8) M-1 s(-1)), and its activity increased with 2 mM dithiothreitol (DTT), at 37 degrees C, pH 5.0. the chelating agent EDTA did not modify the enzyme activity. Inhibition of tegupain by cystatin (K-iapp 2.43 nM), E64 (3.64 nM, 83% inhibition), and the propeptide N-terminal sequence indicate that the toxic activity is due to a novel cysteine proteinase-like enzyme, rendered active upon the hydrolysis of a cotyledon component of C. papaya seeds. (c) 2013 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Dept Bioquim, BR-04044020 São Paulo, BrazilUniv Estadual Norte Fluminense, Biotechnol Lab, Campos Dos Goytacazes, RJ, BrazilUniversidade Federal de São Paulo, Dept Bioquim, BR-04044020 São Paulo, BrazilFAPESP: 2009/17058-6FAPESP: 2009/53766-5Web of Scienc
Mayor producción de inmunoglobulina en ratas suplementadas con ácido linoleico conjugado durante la gestación y la lactancia
Conjugated linoleic acid (CLA) has been reported to exert beneficial physiological effects on body composition and the immune system. However, little information is available on the influence of CLA on immune function during early life periods. The present study evaluates the effect of feeding an 80:20 mixture of cis-9, trans-11- and trans-10, cis-12-CLA isomers during gestation and suckling on the systemic immune response of weaned Wistar rats. Pups received dietary CLA from dams through the placental barrier and during suckling by breast milk (group A) or by oral administration (group B). Pups from group C only received CLA during suckling by oral administration. Group D constituted the reference group. Milk from dams fed the CLA diet had a high content of CLA and higher IgA and IgG concentrations than rats fed the standard diet. The plasma of pups from groups A, B and C showed six, twelve and nine times higher content of the cis-9, trans-11-CLA isomer than that of the group D pups. Rats from group A exhibited higher serum IgG concentrations than rats from the rest of the groups (22·14 (sem 2·14) v. about 5 mg/ml; P < 0·05), whereas rats from groups A and B showed approximately 2-fold higher splenocyte IgM production than rats from groups C and D. However, CLA supplementation did not influence significantly the splenocyte proliferative response or cytokine secretion. Supplementation during gestation and suckling with an 80:20 cis-9, trans-11–trans-10, cis-12 CLA mix enhances the production of the main in vivo and in vitro Ig isotypes in Wistar rats
Dos especies nuevas de Crassulaceae del sur de Jalisco, México
Based on collections from the southern part of the state of Jalisco, Echeveria rulfiana and Villadia ramirezii are described as new species. The former is assigned to series Gibbiflorae and compared with E. marianae, E. novogaliciana, and E. nayaritensis, from which it differs mainly by its caulescent habit and oblanceolate and canaliculate leaves. The latter is related with V. platystyla and can be distinguished by possesing smaller flowers arranged in loose cymes. Both species are narrow endemic elements of southern Jalisco and their conservation statuses are discussed.Con base en colectas procedentes del sur del estado de Jalisco, se describen Echeveria rulfiana y Villadia ramirezii como especies nuevas para la ciencia. La primera se asigna a la serie Gibbiflorae y se compara con E. marianae, E. novogaliciana y E. nayaritensis, de las que se distingue principalmente por la presencia de tallo y por sus hojas oblongas y acanaladas. V. ramirezii parece estar estrechamente relacionada con V. platystyla y se puede separar, entre otros caracteres, por poseer inflorescencias más laxas y flores de menor tamaño. Se discute el estado de conservación de ambas especies, que parecen representar estrechos endemismos en el sur de Jalisco
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