bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporal dynamics of subtidal Zostera marina and intertidal Zostera japonica on the southern coast of Korea
Authors: Lee Sang Yong , Kim Jeong Bae , Lee Sung Mi 
Published: June 2006

AbstractThe temporal dynamics of two seagrass species, Zostera marina and Z. japonica, were monitored monthly in Dadae Bay, Geoje Island, on the southern coast of Korea. Plant morphological characteristics, shoot density, biomass, leaf production, reproductive effort, and environmental characteristics were monitored from July 2001 to July 2002. Zostera japonica occurred in the intertidal zone and Z. marina occurred in the subtidal zone from 0.5 to 2.5 m below the mean low water level. Shoots and rhizomes were significantly larger in Z. marina than in Z. japonica, whereas the shoot density was greater in Z. japonica than in Z. marina. Despite differences in morphology and shoot density, biomass did not differ significantly between the species. Reproduction occurred from April to June in Z. marina and from May to July in Z. japonica. The proportion of reproductive shoots was approximately three times higher in Z. marina than in Z. japonica. Seasonal variation in the biomass of Z. japonica was caused by changes in both shoot size and density, whereas that of Z. marina was mainly caused by changes in shoot length. Leaf production in Z. marina and Z. japonica showed clear seasonal variation, and leaf production in Z. marina (2.6 ± 0.2 g DW·m−2·day−1) was higher than that in Z. japonica (1.7 ± 0.2 g DW·m−2·day−1). The mean plastochrone interval was not significantly different between the two species, whereas the leaf lifetime of Z. marina was longer (69 ± 7.8 days) than that of Z. japonica (59 ± 8.3 days). Our results indicated that seasonal leaf growth patterns in Z. japonica are correlated with irradiance and temperature, whereas those in Z. marina respond most to irradiance. Seasonal changes in irradiance appeared to control the temporal variation in above‐ground biomass in both species.
Annual variability of planktonic ostracods (Crustacea) in the South Adriatic Sea
Authors: Brautović Igor , Bojanić Natalia , Batistić Mirna , Carić Marina 
Published: June 2006

AbstractTemporal variability and population structure of planktonic ostracods were investigated for the first time in the South Adriatic Sea during 1996. The maximal total ostracod abundance (1167 ind·100 m−3; 69% juveniles, 18% females and 13% males) was recorded in February. Thirteen species of marine planktonic ostracods were identified. Porroecia spinirostris and Archiconchoecia striata dominated the ostracod assemblage, accounting respectively for 62% and 18% of the total abundance. Their annual peaks were recorded during the cold season, which was the period of their intense reproduction, with favourable temperature conditions and lack of predators. The females surpassed the males in abundance in most species. The presence of the mesopelagic species indicated a strong influence of intermediate layer water masses from the Eastern Mediterranean Sea.
Effects of temporal dynamics and vertical structure of the seagrassZostera caulescenson distribution and recruitment of the epifaunal encrusting bryozoaMicroporella trigonellata
Authors: Kouchi Naoko , Nakaoka Masahiro , Mukai Hiroshi 
Published: June 2006

AbstractSeagrass is an ephemeral habitat for epifaunal sessile invertebrates attaching on seagrass leaves, and spatial and temporal dynamics of seagrasses strongly affect the distribution of epifauna.Zostera caulescensMiki, a seagrass species endemic to Japan, provides a complex habitat for epifauna with two types of shoots: vegetative, less than 1 m tall, and flowering, 5–7 m tall. We conducted monthly field observations and a manipulative field experiment to investigate the effects of the seagrass vertical structure and its temporal variation on the distribution and recruitment of the encrusting bryozoanMicroporella trigonellata. The density ofM. trigonellataon the leaves of flowering shoots, located at the seagrass canopy, varied temporally, reaching maximum in summer and minimum in winter. In contrast,M. trigonellatadensity on the leaves of vegetative shoots near the sea floor was consistently low throughout the study period. Early recruit bryozoans also showed this temporal and vertical variation in density; thus spatial and temporal variation in recruitment determined the distribution of the whole colonies. The field experiment revealed that the recruitment rate ofM. trigonellatawas significantly higher at the higher position of the water column (3 m above the sea floor) than at the lower position (0.5 m) in June. However, the recruitment rate was higher at the lower position in October when most of the flowering shoots started falling down. The temporal change in bryozoan habitat selection is considered to be adaptive to maintain their population on the seagrass leaves that show complex temporal dynamics.
Community structure of macrobenthos in two tropical sandy beaches with different morphodynamic features, Rio de Janeiro, Brazil
Authors: Fernandes Renata Soares Ramalho , Soares‐Gomes Abilio 
Published: June 2006

AbstractThe macrobenthos of two exposed tropical sandy beaches in Rio de Janeiro (Brazil) were compared in relation to density, species richness, and vertical zonation. Biological and sediment samplings were carried out in the austral winter of 2002 and the austral summer of 2003. The sampling design consisted of 10 transects perpendicular to the water line, evenly divided into strata. A sampling unit was taken in each stratum with a 0.04 m2 quadrat sampler. Beaches were also compared according to physical features, such as slope, wave period, wave height, and grain size. According to Dean's Ω morphodynamic index the Pontal is a dissipative beach while the Costa Azul is a reflective one. The mean grain size ranged from median to coarse sand in Costa Azul, whereas in Pontal it ranged from median to very fine sand. Eleven species were collected in the two beaches. Crustaceans were the dominant in the Costa Azul Beach, while the polychaete Scolelepis squamata dominated the Pontal beach. A negative correlation was found between the density of the macrobenthos and mean grain size, and beach slope. On the other hand, the Dean's parameter correlated positively with faunal density. Based on the results of ANOSIM, in both beaches, two groups of stations were identified, defining an upper and a lower beach zone along the vertical distribution of the macrobenthos.
Biofilm formation and cellulose expression among diverse environmental Pseudomonas isolates
Authors: Ude Susanne , Arnold Dawn L. , Moon Christina D. , Timms‐Wilson Tracey , Spiers Andrew J. 
Published: June 2006

SummaryThe ability to form biofilms is seen as an increasingly important colonization strategy among both pathogenic and environmental bacteria. A survey of 185 plant‐associated, phytopathogenic, soil and river Pseudomonas isolates resulted in 76% producing biofilms at the air–liquid (A–L) interface after selection in static microcosms. Considerable variation in biofilm phenotype was observed, including waxy aggregations, viscous and floccular masses, and physically cohesive biofilms with continuously varying strengths over 1500‐fold. Calcofluor epifluorescent microscopy identified cellulose as the matrix component in biofilms produced by Pseudomonas asplenii, Pseudomonas corrugata, Pseudomonas fluorescens, Pseudomonas marginalis, Pseudomonas putida, Pseudomonas savastanoi and Pseudomonas syringae isolates. Cellulose expression and biofilm formation could be induced by the constitutively active WspR19 mutant of the cyclic‐di‐GMP‐associated, GGDEF domain‐containing response regulator involved in the P. fluorescens SBW25 wrinkly spreader phenotype and cellular aggregation in Pseudomonas aeruginosa PA01. WspR19 could also induce P. putida KT2440, which otherwise did not produce a biofilm or express cellulose, as well as Escherichia coli K12 and Salmonella typhimurium LT2, both of which express cellulose yet lack WspR homologues. Statistical analysis of biofilm parameters suggest that biofilm development is a more complex process than that simply described by the production of attachment and matrix components and bacterial growth. This complexity was also seen in multivariate analysis as a species‐ecological habitat effect, underscoring the fact that in vitro biofilms are abstractions of those surface and volume colonization processes used by bacteria in their natural environments.
The incidence of nirS and nirK and their genetic heterogeneity in cultivated denitrifiers
Authors: Heylen Kim , Gevers Dirk , Vanparys Bram , Wittebolle Lieven , Geets Joke , Boon Nico , De Vos Paul 
Published: June 2006

SummaryGene sequence analysis of nirS and nirK, both encoding nitrite reductases, was performed on cultivated denitrifiers to assess their incidence in different bacterial taxa and their taxonomical value. Almost half of the 227 investigated denitrifying strains did not render an nir amplicon with any of five previously described primers. NirK and nirS were found to be prevalent in Alphaproteobacteria and Betaproteobacteria, respectively, nirK was detected in the Firmicutes and Bacteroidetes and nirS and nirK with equal frequency in the Gammaproteobacteria. These observations deviated from the hitherto reported incidence of nir genes in bacterial taxa. NirS gene phylogeny was congruent with the 16S rRNA gene phylogeny on family or genus level, although some strains did group within clusters of other bacterial classes. Phylogenetic nirK gene sequence analysis was incongruent with the 16S rRNA gene phylogeny. NirK sequences were also found to be significantly more similar to nirK sequences from the same habitat than to nirK sequences retrieved from highly related taxa. This study supports the hypothesis that horizontal gene transfer events of denitrification genes have occurred and underlines that denitrification genes should not be linked with organism diversity of denitrifiers in cultivation‐independent studies.
Towards European climate risk surfaces: the extent and distribution of analogous and non‐analogous climates 1931–2100
Authors: Ohlemüller Ralf , Gritti Emmanuel S. , Sykes Martin T. , Thomas Chris D. 
Published: June 2006

ABSTRACTAim  Climate is an important determinant of species distributions. We assess different aspects of risk arising from future climate change by quantifying changes in the spatial distribution of future climatic conditions compared with the recent past.Location  Europe.Methods  A 10′ × 10′ resolution gridded data set of five climate variables was used to calculate expected changes to the area, distance and direction of 1931–60 climatic conditions under the HadCM3 climate model for four future climate scenarios based on different rates of greenhouse gas emissions (SRES scenarios). Three levels of tolerance ranges determined the thresholds for which future conditions are considered analogous to 1931–60 (pre‐warming) conditions.Results  For many parts of Europe, areas with pre‐warming analogous climate conditions will be smaller and further away in the future than they are now. For any location in Europe, areas with pre‐warming analogous mean annual temperature conditions will, on average, be reduced between 23.7% (B1 scenario) and 49.7% (A1FI scenario) by 2100 when assuming a medium tolerance range. The mean distance to these areas will, on average, increase between 272 km (B1) and 645 km (A1FI). These changes are more pronounced for temperature than for water availability variables and also for narrow tolerance ranges compared to wide tolerance ranges. Using a combined measure of both temperature and precipitation variables, areas with prewarming analogous conditions are predicted to be in a more northeasterly direction in the future, but there are considerable regional differences within Europe.Main conclusions  The results suggest that, for some parts of Europe, the loss of area with any suitable climatic conditions represents the greatest risk to biodiversity, but in other regions the distances that species may have to move to reach suitable climatic conditions may be a greater problem. Quantifying the distance and direction in analyses of change of climatically suitable areas can add additional information for climate change risk assessments.
Misleading Inferences from Panel Unit Root Tests: a Reply*
Authors: Breuer Janice Boucher , McNown Robert , Wallace Myles 
Published: June 2006

AbstractFord et al. (this issue) point out that the SURADF panel unit root test may be sensitive to panel composition. This reply shows that they overstate the case since they focus on a short time series of 44 observations. Type II errors are much more likely in this environment so that inconsistent conclusions may arise for individual panel members across differently composed panels. We demonstrate that this problem becomes much less likely when the number of time‐series observations increases.
On the Equivalence of Ad Valorem Tariffs and Specific Tariffs under Duopoly*
Authors: Shea Koon Lam , Shea Esther Y. P. 
Published: June 2006

AbstractUsing a quantity conjectural variation model, this paper examines whether an ad valorem tariff and a specific tariff are equivalent under duopoly. We show that if the average per‐unit import tax is the same for the two tariffs, domestic output will be smaller while foreign output will be larger under an ad valorem tariff. We further show that for any value of a specific tariff, there is a Pareto‐superior ad valorem tariff for all values of conjectural variation except in the case of perfect competition where the two tariffs are equivalent.
The Division and Size of Gains from Liberalization in Service Networks*
Authors: Bhattarai Keshab , Whalley John 
Published: June 2006

AbstractIf two disjoint country service networks involving a small and large country are connected as part of international liberalization in the presence of network externalities, the per capita gain for the small country from access to a large network will be large, and the per capita gain for the large country will be small. In contrast to goods, the benefits of liberalization in network‐related services are more likely to be approximately equally divided between large and small countries than is true of trade in goods, where benefits accrue disproportionately to the small country. We also argue that non‐cooperation in network‐related services trade may involve more extreme retaliation than suggested for trade in goods by the optimal tariff literature, so that relative to a non‐cooperative outcome, gains from liberalization in network‐related services become larger than from liberalization in goods. We develop simple models which we use for numerical examples showing these points, along with an empirical implementation for global telecoms liberalization for the US, Europe, Canada, and the rest of the world using the framework developed in the paper. This shows similar proportional gains to regions, consistent with the theme of the paper that goods and services liberalization differ.
Oligopsony Distortions and Welfare Implications of Trade*
Authors: Devadoss Stephen , Song Wongun 
Published: June 2006

AbstractWhile imperfect competition in the output market has garnered extensive focus in the new trade theory literature, input market imperfection has received considerably less attention. Since market power in input purchase has been growing in recent years, it is worth examining the welfare implications of trade arising from oligopsony power. We develop a model consisting of two final goods, one intermediate good, and two primary factors (capital and labor). One final good and the intermediate good employ primary factors, whereas the other final good uses labor and the intermediate input. All markets operate under perfect competition except for the intermediate input, which is oligopsonistic. Using this model, we show that oligopsony can lead to some anomalies such as an increase in the oligopsony output, reward to the intensive‐factor in the oligopsony sector, national welfare, and deterioration of terms of trade, but it always decreases the reward to the intermediate input.
The Torrens–Ricardo Principle of Comparative Advantage: an Extension*
Authors: Kemp Murray C. , Okawa Masayuki 
Published: June 2006

AbstractThe Torrens–Ricardo Principle of Comparative Advantage rests on the special assumptions that, both in autarky and under free trade, all countries can produce all commodities and that, in autarkic equilibrium, each country consumes all producible commodities, at least incipiently. We reformulate the Principle to accommodate alternative assumptions. In our reformulation the emphasis is on marginal rates of substitution, not on the traditional marginal rates of transformation in production. It is shown in effect that, in existing formulations, the supply side is assigned a role that it can rarely sustain.
Modeling Cultural Barriers in International Trade
Authors: Kónya István 
Published: June 2006

AbstractThe paper presents a model that analyzes the role of cultural differences in international trade. The decision to study foreign cultures and languages is incorporated into a simple trade model, which captures basic properties of cultural and language barriers. First, cultural costs differ from physical ones in that they can be eliminated by learning. Secondly, learning a language has economies of scale, thus smaller countries tend to invest more into learning. Thirdly, learning decisions within one country impose an externality on trading partners, since learning by one party makes communication easier also for the other one. This implies that learning decisions are in general inefficient, and the paper derives the connection between the equilibrium and optimal outcomes. Finally, because of the substitutability of learning among countries, a policy where a country subsidizes learning in the other nation—“cultural protectionism”—can be rationalized. Under certain conditions, such a policy can improve the welfare of both countries, in contrast to the case of regular export subsidies.
Is the Border Really That Wide?
Authors: Ceglowski Janet 
Published: June 2006

AbstractThis paper analyzes cross‐border price behavior in a three‐dimensional sample of US and Canadian retail prices. Unit‐root tests reveal that a majority of the cross‐border relative price series are stationary and that short‐run cross‐border price differences are eliminated at average speeds comparable to those for intranational prices. Cross‐border convergence is not absolute; the long‐run international price differences average two to three times their intranational counterparts. Moreover, gravity‐type equations reveal a border effect that is sizable but considerably smaller than earlier estimates. These results suggest that, while significant, the Canada–US border may not be the formidable barrier portrayed in previous studies.
Multinational Corporations, Stackelberg Leadership, and Tariff‐jumping
Authors: Dixon Stuart 
Published: June 2006

AbstractIn this paper we consider the traditional entry mode choice of an incumbent monopolist facing entry by a single foreign firm. By allowing entry to be either via exporting or foreign direct investment and for the possibility of Stackelberg equilibria where firms can set quantities in one of two time periods, namely “early” or “late,” we find conditions where both Cournot and Stackelberg equilibria emerge endogenously. Furthermore, by introducing a simple linear tariff, we see that it not only affects the choice of exporting and FDI in a nonlinear way, but that it can also affect the type of equilibrium that emerges.
“GATT‐think” with Asymmetric Countries*
Authors: Epifani Paolo , Vitaloni Juliette 
Published: June 2006

AbstractWe argue that a trade agreement which conforms to GATT’s reciprocity rule benefits the (stronger) less trade‐dependent country at the expense of the (weaker) more trade‐dependent country. Reciprocity is so unfavorable to the weaker country that it may be worse off under reciprocity than under the Nash‐ bargaining solution, a “power‐based” approach to trade negotiations that reflects power asymmetries among trading partners. Our results question Bagwell and Staiger’s (1999, 2000) view of reciprocity as a rule that “serves to mitigate the influence of power asymmetries on negotiated outcomes.”
The neuronal excitatory amino acid transporter EAAC1/EAAT3: does it represent a major actor at the brain excitatory synapse?
Authors: Nieoullon André , Canolle Benoit , Masmejean Frédérique , Guillet Benjamin , Pisano Pascale , Lortet Sylviane 
Published: June 2006

AbstractEAAC1/EAAT3 is a transporter of glutamate (Glu) present at the post‐synaptic neuronal element, in opposition to the two other main transporters, GLAST/EAAT1 and GLT1/EAAT2, expressed at the excitatory amino acid (EAA) synapse by surrounding astrocytes. Although, in the adult, EAAC1/EAAT3 exhibits a rather low expression level and is considered to make a minor contribution to Glu removal from the synapse, its early expression during brain development, before the astrocytes are functional, suggests that such a neuronal transporter is involved in the developmental effects of EAA and, possibly, in the biosynthesis and trophic role of GABA, which is excitatory in nature in different brain regions during the earlier stages of brain development. This neuronal Glu transporter is considered to have a dual action as it is apparently involved in the neuronal uptake of cysteine, which acts as a key substrate for the synthesis of glutathione, a major anti‐oxidant, because the neurones do not express the Xc– transport system in the mature brain. Interestingly, EAAC1/EAAT3 activity/expression was shown to be highly regulated by neuronal activity as well as by intracellular signalling pathways involving primarily α protein kinase C (αPKC) and phosphatidylinositol‐3‐kinase (PI3K). Such regulatory processes could act either at the post‐traductional level or at the transcriptional level. It is worth noting that EAAC1/EAAT3 exhibits specificity, compared with other EAA transporters, because it is present mainly in the intracellular compartment and only for about 20% at the plasma membrane. Variations in neuronal Glu uptake were shown to be associated with rapid changes in the trafficking of the transporter protein altering the membranar location of the transporter. More recent data show that astrocyte‐secreted factors such as cholesterol could also influence rapid changes in the location of EAAC1/EAAT3 between the plasma membrane and the cytoplasmic compartment. Such a highly regulated process of EAAC1/EAAT3 activity/expression may have implications in the physiopathology of major diseases affecting EAA brain signalling, which is further supported by data obtained in animal models of hypoxia–anoxia, for example.