bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climate increases regional tree‐growth variability in Iberian pine forests
Authors: ANDREU LAIA , GUTIÉRREZ EMILIA , MACIAS MARC , RIBAS MONTSE , BOSCH ORIOL , CAMARERO J. JULIO 
Published: February 2007

AbstractTree populations located at the geographical distribution limit of the species may provide valuable information about tree‐growth response to changes on climatic conditions. We established ninePinus nigra, 12P. sylvestrisand 17P. uncinatatree‐ring width chronologies along the eastern and northern Iberian Peninsula, where these species are found at the edge of their natural range. Tree‐growth variability was analyzed using principal component analysis (PCA) for the period 1885–1992. Despite the diversity of species, habitats and climatic regimes, a common macroclimatic signal expressed by the first principal component (PC1) was found. Moreover, considering the PC1 scores as a regional chronology, significant relations were established with Spanish meteorological data. The shared variance held by the tree chronologies, the frequency of narrow rings and the interannual growth variability (sensitivity) increased markedly during the studied period. This shows an enhancement of growth synchrony among forests indicating that climate might have become more limiting to growth. Noticeably, an upward abrupt shift in common variability at the end of the first half of the 20th century was detected. On the other hand, moving‐interval response functions showed a change in the growth–climate relationships during the same period. The relationship between growth and late summer/autumn temperatures of the year before growth (August–September, negative correlation, and November, positive correlation) became stronger. Hence, water stress increase during late summer previous to tree growth could be linked to the larger growth synchrony among sites, suggesting that climate was driving the growth pattern changes. This agrees with the upward trend in temperature observed in these months. Moreover, the higher occurrence of extreme years and the sensitivity increase in the second half of the 20th century were in agreement with an increment in precipitation variability during the growing period. Precipitation variability was positively related to tree‐growth variability, but negatively to radial growth. In conclusion, a change in tree‐growth pattern and in the climatic response of the studied forests was detected since the mid‐20th century and linked to an increase in water stress. These temporal trends were in agreement with the observed increase in warmer conditions and in precipitation variability.
Dispersal propensity and settling preferences of European corn borers in maize field borders
Authors: BAILEY RICHARD I. , BOURGUET DENIS , PALLEC ANNE‐HELENE LE , PONSARD SERGINE 
Published: February 2007

Summary

Bacillus thuringiensis (Bt) crops kill pest larvae but have led to resistance evolution in several target pests. The high dose‐refuge (HDR) strategy aimed at delaying Bt resistance evolution depends on dispersal patterns of target pests. Examination of adult dispersal of the European corn borer Ostrinia nubilalis (ECB), the main target of Bt maize, can help to improve resistance management.
Estimated recapture rates over 20 mark–release–recapture sessions in herbaceous field borders, where ECB adults rest during the day and mate at night, were used to examine the influence of sex, release period and site on ECB dispersal. Data from an additional 30 sessions were used to test the influence of night temperature, humidity, dew index and wind speed.
Average recaptures within 50 m of release were lower 12 h after night (7·7%) than 12 h after day (34·5%) releases, did not differ between sexes, and decreased during nights with higher temperatures and lower wind speed.
Local habitat had a major influence on dispersal. The number of unmarked adults caught initially in a given section of field border was strongly correlated with those subsequently captured in the same section, suggesting that moths flying in from the surroundings consistently settle in the same preferred spots. Moreover, recapture rates of marked adults were positively correlated with the prior density of unmarked adults in the release section.
The spatial distribution of recaptured moths around the release point suggests that they moved on a very local scale, while those not recaptured probably left the area by a different, long‐range type of dispersal.
Synthesis and applications. A proportion of European corn borer adults typically remained within a few metres of their initial location for at least 12 h. This should favour non‐random mating early in the flight season when nights are cold, population mixture is low and most individuals are unmated. Non‐random mating can accelerate the evolution of resistance, but this effect may be offset by non‐random oviposition. Our findings suggest that the intensity and direction of dispersal could be manipulated by field border management. Our data on the range and prevalence of short‐range dispersal and the factors influencing this process, support the view that resistance evolution is multifactorial. Our results can be used to parameterize multifactorial models from which specific management recommendations can be formulated.
Patterns of movement and dispersal in an endangered damselfly and the consequences for its management
Authors: ROUQUETTE JAMES R. , THOMPSON DAVID J. 
Published: February 2007

Summary

Coenagrion mercuriale is one of Europe's rarest and most threatened damselflies. It is listed in the European Community (EC) Habitats and Species Directive and is the only odonate currently given priority status in the UK Biodiversity Action Plan. Information regarding patterns of movement and dispersal in this species is required to guide conservation and management programmes. Management is currently geared towards habitat restoration of isolated subpopulations, with little attention paid to the metapopulation and landscape context.
A multisite mark–release–recapture project was carried out in the valley of the River Itchen in southern England to determine the extent of movement and the factors affecting movement of mature adults of this endangered damselfly. A total of 8708 individuals was marked.
The species was found to be extremely sedentary, with dispersal limited to an area of contiguous habitat. The median net lifetime movement was 31·9 m and 66% of individuals moved less than 50 m in their lifetime. Movements of greater than 500 m were rare and the longest recorded movement was 1·79 km. This makes it the most sedentary odonate that has been studied in the UK.
The highest recapture rates and the lowest movement distances were recorded at the most isolated site. Time between capture and recapture, and day in season had an effect on movement, and individuals travelled further on their first than on subsequent moves. There was no consistent effect of age or sex on distance moved.
There was strong evidence for inverse density‐dependent movement, with individuals moving further in low‐density than high‐density populations. This is the first time that inverse density‐dependent movement has, to our knowledge, been observed in a natural population of odonates.
Synthesis and applications. Coenagrion mercuriale, along with many other invertebrate species of conservation concern, lives in a management‐dependent mid‐successional habitat. However, the species is highly sedentary. Furthermore, patterns of movement and dispersal are strongly affected by landscape structure and population density. This means that it is unable to recolonize isolated sites and requires ‘stepping stone’ habitats to improve its chances of survival in the medium to long term. Suitable habitat management between sites that are beyond the dispersal distance of individuals can be used to connect or reconnect populations. Within existing sites only small sections of habitat should be managed in any one year and new areas should be created close to existing populations. The long‐term persistence of C. mercuriale and other invertebrate species requires a landscape approach to management, with connectivity an important part of management planning. It is clear that carefully conducted studies of movement and dispersal are key components in guiding invertebrate conservation strategies.
Interspecific variation in egg testosterone levels: implications for the evolution of bird song
Authors: GARAMSZEGI L. Z. , BIARD C. , EENS M. , MØLLER A. P. , SAINO N. 
Published: February 2007

AbstractAlthough interspecific variation in maternal effects via testosterone levels can be mediated by natural selection, little is known about the evolutionary consequences of egg testosterone for sexual selection. However, two nonexclusive evolutionary hypotheses predict an interspecific relationship between egg testosterone levels and the elaboration of sexual traits. First, maternal investment may be particularly enhanced in sexually selected species, which should generate a positive relationship. Secondly, high prenatal testosterone levels may constrain the development of sexual characters, which should result in a negative relationship. Here we investigated these hypotheses by exploring the relationship between yolk testosterone levels and features of song in a phylogenetic study of 36 passerine species. We found that song duration and syllable repertoire size were significantly negatively related to testosterone levels in the egg, even if potentially confounding factors were held constant. These relationships imply that high testosterone levels during early development of songs may be detrimental, thus supporting the developmental constraints hypothesis. By contrast, we found significant evidence that song‐post exposure relative to the height of the vegetation is positively related to egg testosterone levels. These results support the hypothesis that high levels of maternal testosterone have evolved in species with intense sexual selection acting on the location of song‐posts. We found nonsignificant effects for intersong interval and song type repertoire size, which may suggest that none of the above hypothesis apply to these traits, or they act simultaneously and have opposing effects.
Predominance of outcrossing in Lymnaea stagnalis despite low apparent fitness costs of self‐fertilization
Authors: PUURTINEN M. , EMILY KNOTT K. , SUONPÄÄ S. , NISSINEN K. , KAITALA V. 
Published: February 2007

AbstractWe have quantified the natural mating system in eight populations of the simultaneously hermaphroditic aquatic snail Lymnaea stagnalis, and studied the ecological and genetic forces that may be directing mating system evolution in this species. We investigated whether the natural mating system can be explained by the availability of mates, by the differential survival of self‐ and cross‐fertilized snails in nature, and by the effects of mating system on parental fecundity and early survival. The natural mating system of L. stagnalis was found to be predominantly cross‐fertilizing. Density of snails in the populations had no relationship with the mating system, suggesting that outcrossing rates are not limited by mate availability at the population densities observed. Contrary to expectations for outcrossing species, we detected no evidence for inbreeding depression in survival in nature with inferential population genetic methods. Further, experimental manipulations of mating system in the laboratory revealed that self‐fertilization had no effect on parental fecundity, and only minor effects on offspring survival. Predominance of cross‐fertilization despite low apparent fitness costs of self‐fertilization is at odds with the paradigm that high self‐fertilization depression is necessary for maintenance of cross‐fertilization in self‐compatible hermaphrodites.
Ecological dynamics of the bivalve‐killing dinoflagellate Heterocapsa circularisquama and its infectious viruses in different locations of western Japan
Authors: Tomaru Yuji , Hata Naotsugu , Masuda Takeshi , Tsuji Masaharu , Igata Kuniyoshi , Masuda Yuji , Yamatogi Toshifumi , Sakaguchi Masao , Nagasaki Keizo 
Published: February 2007

SummaryWe studied the ecological relationships between the bloom‐forming dinoflagellate Heterocapsa circularisquama and its infectious viruses in field surveys conducted in western Japan. The occurrence of H. circularisquama blooms in Imari Bay during 2002 and in Ago Bay during 2002 and 2004 was accompanied by specific increase in abundance of viruses lytic to H. circularisquama. Using northern dot‐blot analysis, ∼96% of the clonal virus isolates collected in the field surveys positively reacted with a molecular probe specific for HcRNAV (H. circularisquama RNA virus); hence, viral impacts on H. circularisquama population observed in these field surveys are considered largely due to HcRNAV and/or its closely related viruses. The dynamics of type UA viruses and type CY viruses having complementary host ranges to H. circularisquama clones were different in each survey and considered to reflect fluctuations in abundance of their suitable host cells in situ. The dynamics of H. circularisquama and its viruses in Ago Bay from 2002 to 2004 suggests the concentration of HcRNAV in the sediment prior to the host's blooming season is a significant factor in determining the size and length of the H. circularisquama blooms. These results support the hypothesis that HcRNAV infection is one of the significant factors affecting the population dynamics of H. circularisquama in both quantity (biomass) and quality (clonal composition).
Coupling between autocatalytic cell death and transparent exopolymeric particle production in the marine cyanobacterium Trichodesmium
Authors: Berman‐Frank Ilana , Rosenberg Gad , Levitan Orly , Haramaty Liti , Mari Xavier 
Published: February 2007

SummaryExtracellular polysaccharide aggregates, operationally defined as transparent exopolymeric particles (TEP), are recognized as an important conduit for carbon recycling and export in aquatic systems. Yet, the factors controlling the build‐up of the TEP pool are not well characterized. Here we show that increased TEP production by Trichodesmium, an oceanic bloom‐forming nitrogen‐fixing (diazotrophic) cyanobacterium, is coupled with autocatalytic programmed cell death (PCD) process. We demonstrate that PCD induction, in both laboratory cultures and natural populations, is characterized by high caspase‐like activity, correlates with enhanced TEP production, and occurs under iron and phosphorus starvation, as well as under high irradiance and oxidative stress. Enhanced TEP production was not observed in actively growing populations. We provide further evidence that iron is a key trigger for the induction of PCD. We demonstrate, for the first time, the concomitant enhanced build‐up of the TEP pool when Trichodesmium is Fe‐stressed. These results suggest a functional linkage between activation of caspases and PCD in Trichodesmium and regulation of vertical carbon and nitrogen fluxes. We hypothesize that modulation of TEP formation and its qualities by different mortality pathways could regulate the fate of phytoplankton blooms and particulate organic matter in aquatic ecosystems.
A technology valuation model to support technology transfer negotiations
Authors: Baek Dong‐Hyun , Sul Wonsik , Hong Kil‐Pyo , Kim Hun 
Published: February 2007

The development and commercialization of advanced technologies will depend increasingly on efficient technology transfer and technology trading systems. This requires the development of technology markets or exchanges and hence a reliable technology valuation methodology. This paper develops a methodology for an objective and impartial valuation of fully developed technologies.A web‐based technology valuation system is developed with which interested users can make efficient and real‐time evaluations of technologies.
An Analysis of Mercosur's Regional Trading Arrangements
Authors: Philippidis G. , Sanjuán A. I. 
Published: February 2007

After six years of stop‐start negotiations, Mercosur is no closer to signing a regional trading agreement (RTA) with the EU, whilst negotiations to finalise a Free Trade of the Americas Agreement (FTAA) have also stalled. This is due to various factors: economic crises in Mercosur, intransigence by member countries and uncertainty surrounding the outcome of the Doha Round. Estimates from the trade literature predict welfare gains to Mercosur from both RTAs whilst only one study assesses the additional benefits of removing non‐tariff barrier (NTB) trade costs which have remained largely unchallenged within the multilateral forum.In this paper, we improve the treatment of NTB estimates employing a theoretically consistent gravity specification, where calculated tariff‐equivalent estimates are subsequently implemented into a modified computable general equilibrium (CGE) model. Relative to a realistic baseline, and incorporating trade‐induced productivity and capital accumulation effects, we reassess the benefits of both regional initiatives to Mercosur, revisiting the claim that NTB trade cost abolition doubles the ‘standard’ welfare estimates. Contrary to previous studies, the results suggest that an FTAA yields greater gains to Mercosur than an EU RTA whilst the claim ofMonteagudo and Watanuki (2003) pertaining to trade cost elimination is understated.
In situ oxygen utilization in the rat intervertebral disc
Authors: Lee Deanna C. , Adams Christopher S. , Albert Todd J. , Shapiro Irving M. , Evans Sydney M. , Koch Cameron J. 
Published: February 2007

AbstractNucleus pulposus cells of the intervertebral disc have no endogenous vasculature and have thus been hypothesized to be hypoxic. This hypothesis was tested using 2‐nitroimidazole, EF5, a drug that at low oxygen concentrations forms covalent adducts with cellular proteins. After administrating EF5 to rats, sections of the intervertebral disc were analysed for EF5 adducts. Drug adducts were quantified in tissue sections using a fluorescent monoclonal antibody. Although the level of EF5 fluorescence in all intervertebral disc tissues was low, the transition zone at the periphery of the nucleus pulposus exhibited the highest level of EF5 binding. To substantiate this result, tissue nitroreductase levels and drug pharmacology were evaluated. Nitroreductase levels were measured in whole discs under severe hypoxia. We noted that there was robust EF5 binding to cells in the annulus fibrosus and transition zone with modest binding to cells of the nucleus pulposus and endplate. High‐performance liquid chromatography analysis indicated limitations in EF5 access to the nucleus pulposus, most probably related to the lack of vasculature and slow drug distribution through the gel‐like interior of the disc. However, despite diffusion problems, the drug dose was determined to be sufficient to report the oxygen status of the nucleus pulposus cells. Based on these findings, we conclude that despite poor vascularization, the disc cells accommodate to the local environment by displaying a limited need for oxygen. Accordingly, the cells of the intervertebral disc are not severely hypoxic.
Morphological effects of two protocols of passive stretch over the immobilized rat soleus muscle
Authors: Gomes Anna R. S. , Cornachione Anabelle , Salvini Tania F. , Mattiello‐Sverzut Ana Cláudia 
Published: February 2007

AbstractThis study evaluated two different stretching protocols employed during a period of hind‐limb immobilization in terms of their effects on muscle morphology. Quantitative data regarding the soleus muscle were obtained based on the clinical hypothesis that a high frequency of this exercise would improve the recovery of muscle structure. Twenty‐four male Wistar rats were divided into four groups (n = 6 each): the control group (C); the immobilized group, in which the left hind limb was immobilized in order to maintain the soleus muscle in a fully shortened position for 3 weeks (I); the ‘immobilized and stretched every 3 days’ group, in which the left hind limb was immobilized as in the immobilized group, but with the soleus muscle stretched every 3 days for 40 min (Ist3); and the ‘immobilized (as in the immobilized group) and stretched every 7 days’ group (ISt7). All soleus muscles were excised 21 days after the beginning of the experiment, and were processed for (1) haematoxylin and eosin and myosin ATPase to evaluate muscle morphology and cross‐sectional area and the proportions of the different fibre types, and (2) ultrastructural analysis. The cross‐sectional area was found to have decreased in all fibre types (I, II and C), mainly in ISt7, when compared with the C group and ISt3 group. The proportion of the different fibre types did not show statistical difference between groups. Light and electron microscopy examination revealed signs of cell degeneration that was more intense in the group immobilized and stretched three times a week. In conclusion, sessions of passive stretching applied to the soleus during immobilization induce muscle fibre injury, suggesting that this therapeutic tool should be applied carefully to disused muscles.
Promoting energy efficiency in small island states: overcoming barriers to the adoption of compact fluorescent lighting in Saint Lucia
Authors: Reynolds Travis W. , DeSisto Thomas P. , Murray Byron , Kolodinsky Jane 
Published: February 2007

AbstractThe ‘island factor’ refers to a series of shared energy‐related issues that many island nations face due to their isolation and limited population size. Under such conditions, one of the only ways to reduce energy costs for consumers is through energy efficiency – including the use of energy‐saving compact fluorescent light bulbs. This study uses consumer survey data to investigate how awareness, past purchasing behaviour, and demographic characteristics influence Saint Lucian consumers’ intentions to purchase energy‐saving compact fluorescent bulbs. The findings indicate that a lack of awareness and understanding of energy efficiency, combined with high product costs and a lack of product availability currently inhibit the adoption of compact fluorescent technologies by Saint Lucian consumers. Awareness of energy efficiency, income and geographic location are identified as significant factors related to increased use of and willingness to pay for compact fluorescent bulbs. In the discussion, possibilities for public education and cost subsidy for compact fluorescent bulb promotion are proposed.
Microsatellite DNA markers for American shad (Alosa sapidissima) and cross‐species amplification within the family Clupeidae
Authors: JULIAN SHANNON E. , BARTRON MEREDITH L. 
Published: February 2007

AbstractSixteen microsatellite loci were identified and characterized for American shad (Alosa sapidissima). The number of alleles per locus observed ranged from eight to 32 and averaged 15.4 alleles. Average observed heterozygosity was 81.1%. The markers were screened using four other species from the family Clupeidae. Amplification success among Alosa species was 79.2% with 81.6% polymorphism among those markers that amplified successfully. Amplification success was poor in Dorosoma (31.3%). Due to allelic diversity and estimates of heterozygosity, these markers can be useful in A. sapidissima for population level analyses, parentage assignment and broodstock management.
Development and characterization of microsatellite loci in the eastern chipmunk (Tamias striatus)
Authors: PETERS MAUREEN B. , GLENN JULIE L. , SVETE PAM , HAGEN CRIS , TSYUSKO OLGA V. , DECOURSEY PATRICIA , LIEUTENANT‐GOSSELIN MÉLISSA , GARANT DANY , GLENN TRAVIS C. 
Published: February 2007

AbstractWe isolated and characterized 16 microsatellite loci in the eastern chipmunk, Tamias striatus. The loci were screened across 25 individuals from one population and shown to be polymorphic with the number of alleles per locus ranging from two to 17. Polymorphic information content ranged from 0.212 to 0.887 and observed heterozygosity ranged from 0.200 to 0.960. Only two loci (Chip 10 and Chip 25) deviated from Hardy–Weinberg equilibrium.