bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine‐scale genetic structure and its consequence in breeding aggregations of a passerine bird
Authors: LEE JIN‐WON , JANG BYOUNG‐SOON , DAWSON DEBORAH A. , BURKE TERRY , HATCHWELL BEN J. 
Published: May 2009

AbstractThe pattern of fine‐scale genetic structure in a population may reflect current biological processes of the species, such as natal dispersal, the breeding system and demography. We investigated the spatial distribution of nests and fine‐scale genetic structure during two breeding seasons in a population of a weakly territorial, flock‐living passerine bird, the vinous‐throated parrotbill,Paradoxornis webbianus. Nest distribution was clustered. There were two peaks of egg laying within each breeding season, and spatial clustering of nests was more extreme during the second peak after controlling for breeding density. The patterns of genetic structure during the breeding season varied with parental sex and season. Genetic structure occurred during the second laying peak: males breeding within 200 m of one another at this time were significantly more closely related than males breeding farther apart. However, no apparent genetic structure was detected in males during the first laying peak or among females in either laying peak. These results reveal male‐oriented kin affiliation during part of the breeding season in this species. Furthermore, juvenile recruitment into the winter flocks was positively related to this increased relatedness among males via kin affiliation. This study implies that fine‐scale genetic structure during the breeding season could be a factor determining individual fitness and may play an important role in our understanding of the evolution of social systems.
Does the ribosome have initiation and elongation modes of translation?
Authors: Tenson Tanel , Hauryliuk Vasili 
Published: May 2009

SummaryRNA polymerases differ functionally and structurally in the initiation phase of transcription, when polymerization of 8–12 nucleotides occurs, from the later phases of transcription. Here we argue that the ribosome also might have different properties when translating the first codons in open reading frames, as compared with the later phases of translation.
The dual specificity phosphatase Rok1 negatively regulates mating and pathogenicity in Ustilago maydis
Authors: Di Stasio Maurizio , Brefort Thomas , Mendoza‐Mendoza Artemio , Münch Karin , Kahmann Regine 
Published: May 2009

SummaryIn the phytopathogenic fungus Ustilago maydis a conserved mitogen‐activated‐protein‐kinase (MAPK) module regulates sexual and pathogenic development. Kpp2 is the central MAPK of this module and is required for transcriptional and morphological responses to pheromone. Upon perception of the pheromone signal Kpp2 is phosphorylated by the MAPK kinase Fuz7. Here we demonstrate that the MAPK Kpp6, which has a partially redundant function with Kpp2, is also phosphorylated by Fuz7. We show that Rok1, a putative dual specificity phosphatase for MAPK signalling, controls the phosphorylation of Kpp2 as well as of Kpp6. rok1 mutants display increased filamentation and are enhanced in virulence. The enhanced virulence is caused by more efficient appressorium formation as well as plant invasion. Overexpression of rok1 reduced conjugation hyphae formation and strongly attenuated pathogenicity. This places Rok1 in a negative feedback loop regulating Kpp2 and Kpp6 activity upon pheromone stimulation and plant colonization.
Evolution, architecture and hierarchy of distributary deep‐water deposits: a high‐resolution outcrop investigation from the Permian Karoo Basin, South Africa
Authors: PRÉLAT A. , HODGSON D. M. , FLINT S. S. 
Published: May 2009

AbstractSea floor and shallow seismic data sets of terminal submarine fan lobes can provide excellent planform timeslices of distributive deep‐water systems but commonly only limited information on cross‐sectional architecture. Extensive outcrops in the Tanqua depocentre, south‐west Karoo Basin, provide these three‐dimensional constraints on lithofacies distributions, stacking patterns, depositional geometries and the stratigraphic evolution of submarine lobe deposits at a scale comparable with modern lobe systems. Detailed study (bed‐scale) of a single‐lobe complex (Fan 3) over a 15 km by 8 km area has helped to define a four‐fold hierarchy of depositional elements from bed through to lobe element, lobe and lobe complex. The Fan 3 lobe complex comprises six distinct fine‐grained sandstone packages, interpreted as lobes, which display compensational stacking patterns on a 5 km scale. Between successive lobes are thin‐bedded, very fine‐grained sandstones and siltstones that do not change lithofacies over several kilometres and therefore are identified as a different architectural element. Each lobe is built by many lobe elements, which also display compensational stacking patterns over a kilometre scale. Thickness variations of lobe elements can be extremely abrupt without erosion, particularly in distal areas where isopach maps reveal a finger‐like distal fringe to lobes. Lobe deposits, therefore, are not simple radial sheet‐dominated systems as commonly envisaged.
Zircon alteration, formation and preservation in sandstones
Authors: HAY DUNCAN C. , DEMPSTER TIM J. 
Published: May 2009

AbstractZircon textures, chemistry and microstructures have been characterized in situ within Carboniferous sandstones from the Midland Valley of Scotland using back‐scattered electron and cathodoluminescence images, electron backscatter diffraction techniques and chemical analyses. The study of polished thin sections reveals a variety of zircon types including unmodified detrital zircon, zircon outgrowths and different forms of modified zircon that formed in low‐temperature conditions within the sedimentary rocks. These rocks have only experienced temperatures of <100 °C during burial; however, altered zircon is abundant and characterized by a low mean atomic number, with relatively high contents of non‐formula elements and a nano‐crystalline or microcrystalline structure. It forms by replacement of detrital zircon that subsequently became metamict. Two types of replacement mechanisms are effective in sedimentary environments and involve either dissolution–reprecipitation or solid‐state reaction, but both require fluid access to the radiation‐damaged areas. The former process appears to become the dominant replacement mechanism as temperature increases and produces highly porous, inclusion‐rich zircon. Metamict zircon is extremely reactive in near‐surface conditions and the production of low‐temperature zircon is sensitive to both parent zircon characteristics and environmental conditions. As such, the alteration of zircon has the potential to yield unique information on the diagenetic history of sedimentary rocks. Low‐temperature zircon would be unlikely to survive sedimentary transport or the rock crushing procedures that characterize many investigations of detrital zircon populations and consequently may generate severe biases in studies of this type.
New species of freshwaterUlva,Ulva limnetica(Ulvales, Ulvophyceae) from the Ryukyu Islands, Japan
Authors: Ichihara Kensuke , Arai Shogo , Uchimura Masayuki , Fay Etienne J. , Ebata Hiroki , Hiraoka Masanori , Shimada Satoshi 
Published: May 2009

SUMMARYUlva limneticaIchihara et Shimada, sp. nov. (Ulvales, Ulvophyceae) is described from the Ryukyu Islands, Japan, and is characterized by thalli that are: (i) branched, tubular, fragile and wrinkled; (ii) up to 80 cm in height and up to 2 cm in diameter; (iii) light to yellowish green in color; and (iv) having an asexual reproduction by means of quadriflagellate swarmers. Rhizoidal cells bear tubular extensions on the outside of the cell layer in the stipe.Ulva limneticais distinguished from species with similar thalli by chloroplast disposition, branching pattern, number of pyrenoids per cell and gross morphology. It is also distinguished by sequences of the nuclear‐encoded 18S ribosomal RNA gene, internal transcribed spacer 2 region and the plastid‐encoded large subunit of ribulose‐1,5‐bisphosphate carboxylase/oxgenase gene (rbcL).Ulva limneticawas clustered with otherUlvaspecies in an early diverging lineage within the genus.
Living in Vulcan's forge: Algal adaptation to stressful geothermal ponds on Vulcano Island (southern Italy) as a result of pre‐selective mutations
Authors: López‐Rodas Victoria , Costas Eduardo , Maneiro Emilia , Marvá Fernando , Rouco Mónica , Delgado Antonio , Flores‐Moya Antonio 
Published: May 2009

SUMMARYFour species of eukaryotic algae proliferate in the sulfureous, acidic (pH 3.1) water of the largest geothermal pond on Vulcano Island (southern Italy). Consequently, this pond constitutes a natural laboratory for analysis of adaptation by phytoplankters to extremely stressful conditions. To distinguish between the pre‐selective or post‐selective origin of adaptation processes allowing the existence of phytoplankters in the pond, a Luria‐Delbrück fluctuation test was carried out with the chlorophycean Dictyosphaerium chlorelloides and the cyanobacterium Microcystis aeruginosa, both isolated from non‐extreme waters; natural water from the Vulcano Island pond was used as selective factor. Preselective, resistant D. chlorelloides cells appeared with a frequency of 4.7 × 10−7 per cell per generation. We propose that the micro‐algae inhabiting this stressful pond could be the descendents of chance mutants that arrived in the past or are even arriving at the present. The genetic adaptation of D. chlorelloides to Vulcano waters could help to explain the survival of photosynthesizers in very stressful geothermal waters during the Neoproterozoic ‘snowball Earth’, a period when primary production collapsed in the biosphere. On the other hand, adaptation to these conditions was not observed in M. aeruginosa, suggesting that cyanobacteria may not be able to develop any kind of adaptation to Vulcano pond water.
Phenology ofSirodotia suecica(Batrachospermaceae, Rhodophyta) in a high‐altitude stream in central Mexico
Authors: Carmona Javier , Bojorge‐García Miriam , Beltrán Yenny , Ramírez‐Rodríguez Rocio 
Published: May 2009

SUMMARYThe morphology and phenology of a monoecious population ofSirodotia suecicaKylin was evaluated seasonally in a central Mexican fifth‐order high‐altitude stream. Abundance of gametophytes is positively correlated with concentrations of total dissolved solids, specific conductivity and total ionic concentration; being present the whole dry season and disappearing in the rainy season. The gametophytes grew in eutrophic circumstances and particular microhabitat conditions: high current velocity (66–122 cm s−1), low irradiance (75–263 µmol photons m−2 s−1) and shallow depth (7–26 cm). Percent cover of gametophytes ranged from 5–90% and significant differences in abundance were not observed when alga was present. Some morphological and reproductive characteristics seem to be adaptations to high current velocity: abundant secondary branches, spermatangia and carpogonia. ‘Chantransia’ stage, microscopic creeping filaments associated with the base of the gametophyte, were not observed in natural conditions. In terms of reproductive success, the population studied can be regarded as highly efficient, considering the high fertilized carpogonia rate, similar to monoecious populations in lotic habitats. HoweverS. suecicawas not common in the study region because it was restricted to particular microhabitat conditions.
Research note: Ecotype differentiation in qualitative content of water soluble organic compounds between marine and brackish Fucus vesiculosus L. (Phaeophyceae)
Authors: Gylle A. Maria , Isaksson Dan , Ekelund Nils G.A. 
Published: May 2009

SUMMARYIn the present study we compared the contents of water soluble organic compounds of the marine intertidal ecotype of Fucus vesiculosus (Phaeophyceae) from the Norwegian Sea (34 practical salinity units, psu) with the sublittoral ecotype of F. vesiculosus from the brackish Bothnian Sea (5 psu). Nuclear magnetic resonance spectra revealed that marine F. vesiculosus had additional types of water soluble organic compounds compared with brackish F. vesiculosus. The results suggested that glycine betaine in the marine ecotype could be the reason for this ecotype differentiation. Furthermore, the qualitative differences between the ecotypes were the same after one week's treatment of marine algae in brackish water and of brackish algae in marine water. These suggest that the additional types of water soluble organic compounds in marine F. vesiculosus are not caused by the salinity conditions at the growth sites. Further research concerning other environmental factors that may influence ecotype differentiation of water soluble organic compounds qualitative content and adaptation in F. vesiculosus is recommended.
Research note: Comparison of growth and nitrate uptake by New England Porphyra species from different tidal elevations in relation to desiccation
Authors: Kim Jang K. , Kraemer George P. , Yarish Charles 
Published: May 2009

SUMMARYDesiccation stress can determine the upper distribution limits and may enhance the uptake of nitrate and ammonium of eulittoral algal species. Upper shore species may exhibit greater stimulation of nitrate uptake following desiccation and achieve maximum uptake at higher desiccation levels. The objective of this study was to determine whether Porphyra species from different vertical elevations respond differently to the desiccation stress, in terms of growth and nitrate uptake. A eulittoral species (Porphyra umbilicalis) and a sublittoral species (P. amplissima) were compared in the present study. Samples were exposed to air for 0, 30 min (40 ± 10% water loss) and 2 h (90 ± 5% water loss), after an initial 4 h light period every day. Desiccation was more stressful to the sublittoral species, Porphyra amplissima, than to the eulittoral species, P. umbilicalis. When tissues were exposed for 2 h daily, P. amplissima lost weight over a 24 h day, while the growth rate of P. umbilicalis dropped by only 30% compared with that of continuously submerged blades. Nitrate uptake rate of sublittoral P. amplissima was only 73% (40 ± 10% water loss) and 62% (90 ± 5% water loss) of that of continuously submerged tissue. Nitrate uptake rates of P. umbilicalis were not significantly affected by desiccation. These results suggest that species in the eulittoral zone, which have longer exposure times, have a higher time‐use efficiency than the sublittoral species in terms of nitrate uptake. This indicates a possible correlation between nitrate uptake and observed vertical distribution patterns.
Trafficking of neurokinin‐1 receptors in serotonin neurons is controlled by substance P within the rat dorsal raphe nucleus
Authors: Lacoste Baptiste , Riad Mustapha , Ratté Marc‐Olivier , Boye Sandra M. , Lévesque Daniel , Descarries Laurent 
Published: May 2009

AbstractSubstance P (SP) modulates serotonin neurotransmission via neurokinin‐1 receptors (NK1rs), and exerts regulatory effects on mood through habenular afferents to the dorsal raphe nucleus (DRN). We have previously demonstrated that, in the caudal DRN of rat, some serotonin neurons are endowed with NK1rs that are mostly cytoplasmic, whereas these receptors are mostly membrane bound in non‐serotonin neurons. Here, we first examined by double‐labeling immunocytochemistry the relationships between SP axon terminals and these two categories of DRN neurons. Almost half of the SP terminals were synaptic and many were in close contact with serotonin dendrites, but never with non‐serotonin dendrites. In additional double‐immunolabeling experiments, most if not all dendrites bearing membranous NK1rs appeared to be GABAergic. Treatment with the selective neurokinin‐1 antagonist RP67580 modified the subcellular distribution of NK1rs in serotonin neurons. At 1 h after administration of a single dose, the receptor distribution was unchanged in both dendritic types but, after daily administration for 7 or 21 days, the plasma membrane and cytoplasmic density of NK1rs were increased in serotonin dendrites, without any change in non‐serotonin dendrites. These treatments also increased NK1r gene expression in the caudal DRN. Lastly, a marked increase in the membrane (but not cytoplasmic) density of NK1rs was measured in serotonin dendrites after bilateral habenular lesion. These results suggest that the trafficking of NK1rs represents a cellular mechanism in control of the modulation of serotonin neuron activity by SP in DRN.
Reflexive Evaluation of an Academic–Industry Research Collaboration: Can Mode 2 Management Research be Achieved?
Authors: Mitev Nathalie , Venters Will 
Published: May 2009

abstractWe present a reflexive retrospective account of a UK government research council funded project deploying knowledge management software to support environmental sustainability in the construction industry. This project was set up in a form typical of a Mode 2 research programme involving several academic institutions and industrial partners, and aspiring to fulfil the Mode 2 criteria seen as transdisciplinarity and business relevance. The multidisciplinary nature is analysed through retrospectively reflecting upon the research process and activities we carried out, and is found to be problematic. No real consensus was reached between the partners on the ‘context of application’. Difficulties between industry and academia, within industry and within academia led to diverging agendas and different alignments for participants. The context of application does not (pre‐)exist independently of institutional influences, and in itself cannot drive transdisciplinarity since it is subject to competing claims and negotiations. There were unresolved tensions in terms of private vs. public construction companies and their expectations of ICT‐based knowledge management, and in terms of the sustainable construction agenda. This post hoc reflexive account, enables us to critique our own roles in having developed a managerial technology for technically sophisticated and powerful private industrial actors to the detriment of public sector construction partners, having bypassed sustainability issues, and not reached transdisciplinarity. We argue that this is due to institutional pressures and instrumentalization from academia, industry and government and a restricted notion of business relevance. There exists a politically motivated tendency to oppose Mode 1 academic research to practitioner‐oriented Mode 2 approaches to management research. We argue that valuing the links between co‐existing Mode 1 and 2 research activities would support a more genuine and fuller exploration of the context of application.
VARIATIONAL BAYESIAN ANALYSIS FOR HIDDEN MARKOV MODELS
Authors: McGrory C. A. , Titterington D. M. 
Published: May 2009

SummaryThe variational approach to Bayesian inference enables simultaneous estimation of model parameters and model complexity. An interesting feature of this approach is that it also leads to an automatic choice of model complexity. Empirical results from the analysis of hidden Markov models with Gaussian observation densities illustrate this. If the variational algorithm is initialized with a large number of hidden states, redundant states are eliminated as the method converges to a solution, thereby leading to a selection of the number of hidden states. In addition, through the use of a variational approximation, the deviance information criterion for Bayesian model selection can be extended to the hidden Markov model framework. Calculation of the deviance information criterion provides a further tool for model selection, which can be used in conjunction with the variational approach.
UPPER BOUNDS ON THE MINIMUM COVERAGE PROBABILITY OF CONFIDENCE INTERVALS IN REGRESSION AFTER MODEL SELECTION
Authors: Kabaila Paul , Giri Khageswor 
Published: May 2009

SummaryWe consider a linear regression model, with the parameter of interest a specified linear combination of the components of the regression parameter vector. We suppose that, as a first step, a data‐based model selection (e.g. by preliminary hypothesis tests or minimizing the Akaike information criterion – AIC) is used to select a model. It is common statistical practice to then construct a confidence interval for the parameter of interest, based on the assumption that the selected model had been given to us a priori. This assumption is false, and it can lead to a confidence interval with poor coverage properties. We provide an easily computed finite‐sample upper bound (calculated by repeated numerical evaluation of a double integral) to the minimum coverage probability of this confidence interval. This bound applies for model selection by any of the following methods: minimum AIC, minimum Bayesian information criterion (BIC), maximum adjusted R2, minimum Mallows' CP and t‐tests. The importance of this upper bound is that it delineates general categories of design matrices and model selection procedures for which this confidence interval has poor coverage properties. This upper bound is shown to be a finite‐sample analogue of an earlier large‐sample upper bound due to Kabaila and Leeb.
The Co‐movement of Credit Default Swap, Bond and Stock Markets: an Empirical Analysis
Authors: Norden Lars , Weber Martin 
Published: May 2009

Abstract We analyse the relationship between credit default swap (CDS), bond and stock markets during 2000–2002. Focusing on the intertemporal co‐movement, we examine monthly, weekly and daily lead‐lag relationships in a vector autoregressive model and the adjustment between markets caused by cointegration. First, we find that stock returns lead CDS and bond spread changes. Second, CDS spread changes Granger cause bond spread changes for a higher number of firms than vice versa. Third, the CDS market is more sensitive to the stock market than the bond market and the strength of the co‐movement increases the lower the credit quality and the larger the bond issues. Finally, the CDS market contributes more to price discovery than the bond market and this effect is stronger for US than for European firms.
Why Do Western European Firms Issue Convertibles Instead of Straight Debt or Equity?
Authors: Dutordoir Marie , Van de Gucht Linda 
Published: May 2009

Abstract Unlike their US counterparts, European convertible debt issuers tend to be large companies with small debt‐ and equity‐related financing costs. Therefore, it is puzzling why these firms issue convertibles instead of standard financing instruments. This paper examines European convertible debt issuer motivations by estimating a security choice model that incorporates convertibles, straight debt, and equity. We find that European convertibles are used as sweetened debt, not as delayed equity. This motivation is reflected in the debt‐like design of most European convertible issues.
Market Feedback, Investment Constraints, and Managerial Behavior
Authors: Hill Paula , Hillier David 
Published: May 2009

Abstract This paper examines the joint role of market feedback and investment constraints on managerial behavior. Using a sample of UK fixed price initial public offerings, we show that underperformance of share returns at the IPO significantly affects managerial investment decisions in the period after the offering. Firms with better investment opportunities and proportionately lower fixed (higher intangible) assets are more sensitive to negative market feedback. Over the longer term, the more responsive firms perform significantly better than their non‐responsive counterparts. The findings contribute to the debate on the informational advantage of managers over investors and present strong evidence that the market, on aggregate, can provide a superior assessment of a firm's opportunities. Managers who are able to respond to negative market feedback can significantly improve their firm's future prospects.