bluuebunny/crossref_metadata_2025_split huggingface dataset:
ORIGINAL ARTICLE: The biogeography of avian extinctions on oceanic islands
Authors: Karels Tim J. , Dobson F. Stephen , Trevino Heather S. , Skibiel Amy L. 
Published: May 2008

AbstractAim  To test the influences of island area, island isolation, and human‐introduced mammalian predators on avian extinctions that have occurred on oceanic islands worldwide.Location  The oceanic islands of the world.Methods  We augmented and re‐examined an existing data set for 218 oceanic islands by means of causal modelling using path analysis (a form of structural equation modelling) and a null model.Results  The number of extinctions was not a simple function of the number of bird species on the various islands. Whereas introduced mammalian predators had an influence on the number of extinctions, island area (via indirect influences) and isolation (via direct influences) were equally or more important.Main conclusions  The multiple influences of physical and biotic factors on past extinctions can be revealed through modelling the causal influences of physical attributes of islands on biological characteristics, and the causal influences of both physical and biological characteristics on extinctions.
ORIGINAL ARTICLE: Not as the crow flies: assessing effective isolation for island biogeographical analysis
Authors: Diver Kim C. 
Published: May 2008

AbstractAim To evaluate the role of island isolation in explaining the distribution of vascular plant species in a dense freshwater archipelago, specifically comparing conventional measures of island isolation with landscape measures of island isolation.Location Data were collected from 35 islands within Massasauga Provincial Park on the eastern shores of the Georgian Bay, Ontario, Canada.Methods Sampled islands were located using stratified random selection based on location and size variation. The number of species was recorded along stratified random transects. Island isolation variables included distance to the mainland, distance to the nearest island, largest gap in a stepping‐stone sequence, distance to the closest upwind point of land, and a landscape measure of island isolation. The landscape measure of isolation was quantified as the percentage of the land area within 100, 250, 500, 1000, 1500 and 2000 m of each island’s perimeter. The isolation variables were calculated within a geographical information system (GIS). Dependent variables in the regression analyses included species richness, the logarithm of species richness and residuals of the species–area relationship. Independent variables included island isolation variables and their logarithmic transformations.Results Isolation plays a role, albeit small, in explaining species richness in the study area. In the regression analyses, the landscape measure of isolation provided a better fit than conventional measures of island isolation. Islands with less land than water within a 250‐m buffer were more effectively isolated and had fewer species present than islands surrounded by a greater proportion of water.Main conclusions Consistent with the species–isolation relationship, fewer species were present on more isolated islands within the Massasauga study area, as elucidated using a series of island buffers in a GIS. Applying a landscape measure of isolation to similar dense, freshwater archipelagos may elucidate species–isolation patterns not evident through conventional, straight‐line distance measurements of island isolation. The low value of the regression coefficients as well as the isolation history and high density of the Massasauga islands suggests caution in extending the results, especially to dissimilar archipelagos.
The invasive plant Alliaria petiolata (garlic mustard) inhibits ectomycorrhizal fungi in its introduced range
Authors: Wolfe Benjamin E. , Rodgers Vikki L. , Stinson Kristina A. , Pringle Anne 
Published: May 2008

Summary

Ectomycorrhizal (EM) fungi play key roles in forest ecosystems, but the potential effects of invasive plants on EM fungal communities have not been assessed. In this study, we tested whether the non‐mycorrhizal herbaceous plant Alliaria petiolata (garlic mustard) can alter the abundance of EM fungal communities in North America.
In three forests in New England, USA, we compared EM root tip abundance in soils where A. petiolata had invaded to adjacent areas without a history of A. petiolata invasion. At one site, we also intensively sampled EM root tip abundance across the edges of A. petiolata patches to determine the spatial pattern of A. petiolata effects on EM fungi. In a glasshouse experiment, we experimentally invaded soils with A. petiolata and Impatiens capensis, a native species and compared EM fungal colonization of white pine (Pinus strobus) seedlings grown in both soils. We also measured the effect of the A. petiolata allelochemical benzyl isothiocyanate on the growth of three species of EM fungi in pure culture.
In the field, EM fungal root tip biomass was lower in invaded soils, with the strongest reductions observed in forests dominated by conifers. Alliaria petiolata invasion did not have a significant effect on total root biomass. The influence of A. petiolata on EM fungal abundance in the field was localized, with the strongest inhibition observed within 10 cm of the edge of A. petiolata patches.
Pine seedlings growing in soils that were experimentally invaded with A. petiolata also had lower EM fungal root tip biomass compared to uninvaded soils. The native species I. capensis caused similar reductions in EM fungal colonization. Growth of pure cultures of all three species of EM fungi was completely inhibited by benzyl isothiocyanate.
Synthesis. Alliaria petiolata inhibits the growth of EM fungi in forests of its introduced range. Changes in EM fungal communities caused by the invasion of A. petiolata may influence tree seedling establishment and biogeochemical cycling.
Volatiles of myrmecophytic Piper plants signal stem tissue damage to inhabiting Pheidole ant‐partners
Authors: Mayer Veronika , Schaber Daniel , Hadacek Franz 
Published: May 2008

Summary

The major aim of this paper was to explore the mechanistic basis of induced defensive ant response in myrmecophytic Piper species and their ant‐partner Pheidole bicornis by combining experimental trials and chemical analysis.
In field experiments, the response of Pheidole ants to simulated stem‐damage of their host plant was documented. Their reaction to other myrmecophytic and non‐myrmecophytic Piper species was explored by fixing respective stem sections onto inhabited Piper fimbriulatum individuals. After artificial damage to stems of P. fimbriulatum and stem sections from other myrmecophytic Piper, the number of ants increased to a maximum of 63 individuals on the damaged internode within the first 10 min. By contrast, no or only a poor reaction was elicited by stem sections from the selected non‐myrmecophytic Piper species.
Solid‐phase microextraction/gas chromatography–mass spectrometry identified 68 volatile organic compounds (VOCs) which were emitted from wounded stem bark of three myrmecophytic (P. fimbriulatum, P. obliquum, P. sagittifolium) and two non‐myrmecophytic (P. hispidum, P. riparense) Piper species, comprising monoterpenes, sesquiterpenes, simple aromatic compounds, and green leaf volatiles (GLVs, oxylipins). Despite considerable variation in the VOC profiles, an analysis of similarities (anosim) classified the accumulation of the sesquiterpenes β‐caryophyllene, germacrene D and emission of the oxylipin reactive electrophilic species (RES) compounds hexanal, cis‐3‐hexene‐1‐ol, 2‐hexenal, 2‐undecanone and 1‐hexanol as characteristic of the myrmecophytic species.
Synthesis. Field experiments showed that mechanical disturbance of myrmecophytic Piper stems is not sufficient to elicit recruitment and alertness of the ant‐partner Ph. bicornis, but that specific volatiles released from the host plant are responsible. Analyses of the VOCs identified after simulated stem damage of three myrmecophytic and two non‐myrmecophytic Piper species revealed differences in their VOC emission profiles: Only in the myrmecophytic species were induced stress compounds found, such as various oxylipin RES or the sesquiterpene β‐caryophyllene, which are typically emitted after plant damage for interplant signalling. Some of these compounds (e.g. hexanal, 1‐hexanol) are known to induce alerting and alarm behaviours in several ant species. Our study provides evidence that the VOCs of the Piper host plant may signal stem damage and induce recruitment and alert behaviour of associated Pheidole ants.
Ecogenomics of cleistogamous and chasmogamous flowering: genome‐wide gene expression patterns from cross‐species microarray analysis in Cardamine kokaiensis (Brassicaceae)
Authors: Morinaga Shin‐Ichi , Nagano Atsushi J. , Miyazaki Saori , Kubo Minoru , Demura Taku , Fukuda Hiroo , Sakai Satoki , Hasebe Mitsuyasu 
Published: May 2008

Summary

Cleistogamy is a mating system found in approximately 300 species of flowering plants. Cleistogamous plants produce closed (cleistogamous, CL) flowers that require obligate self‐pollination and open (chasmogamous, CH) flowers that allow for outcross‐pollination. CL and CH flowers are induced by various environmental factors; this appears to be an adaptive mating strategy in unpredictable environments.
We examined the molecular basis of CL and CH flowering in Cardamine kokaiensis, which is closely related to the model flowering plant Arabidopsis thaliana. CL and CH flowering should be regulated by gene expression that is dependent on environmental conditions. By elucidating the molecular basis of CL and CH flowering, we can determine the changes in gene regulatory networks involved in the transition from CH to CL flowering. Furthermore, these results may help clarify the molecular evolutionary mechanisms leading to cleistogamy.
We regulated CL and CH flowering of C. kokaiensis using chilling treatments in a growth chamber. In a control treatment without chilling, C. kokaiensis produced CH and intermediate (INT) flowers. Long chilling of seedlings led to INT flowers, while long chilling of seeds induced the formation of CL flowers. Chilling seeds, and to a lesser extent of seedlings, induced early flowering and small plant size at flowering.
We also conducted a cross‐species microarray analysis to compare gene expression patterns between CL and CH flowers using genomic DNA‐based probe‐selection strategy in an A. thaliana microarray. In this result, 69 genes, including genes related to floral development, auxin, flowering time, cold‐stress, and drought‐stress, were differentially expressed between CL and CH flowers.
Synthesis. This is the first report on the molecular basis of cleistogamy. We hypothesize that the interaction between the genetic network of the chilling response and that of floral development has been important in the evolution of cleistogamy in C. kokaiensis. Our results help to clarify the molecular basis for the evolution of plant mating systems that depend on environmental conditions.
Assessing the extent of genome‐wide intralocus sexual conflict via experimentally enforced gender‐limited selection
Authors: MORROW E. H. , STEWART A. D. , RICE W. R. 
Published: May 2008

AbstractIntralocus sexual conflict, which occurs when a trait is selected in opposite directions in the two sexes, is a taxonomically widespread phenomenon. The strongest genetic evidence for a gender load due to intralocus sexual conflict comes from the Drosophila melanogaster laboratory model system, in which a negative genetic correlation between male and female lifetime fitness has been observed. Here, using a D. melanogaster model system, we utilize a novel modification of the ‘middle class neighbourhood’ design to relax selection in one sex, while maintaining selection in the other. After 26 generations of asymmetrical selection, we observed the expected drop in fitness of the non‐selected sex compared to that of the selected sex, consistent with previous studies of intralocus sexual conflict in this species. However, the fitness of the selected sex also dropped compared to the base population. The overall decline in fitness of both the selected and the unselected sex indicates that most new mutations are harmful to both sexes, causing recurrent mutation to build a positive genetic correlation for fitness between the sexes. However, the steeper decay in the fitness of the unselected sex indicates that a substantial number of mutations are gender‐limited in expression or sexually antagonistic. Our experiment cannot definitively resolve these two possibilities, but we use recent genomic data and results from previous studies to argue that sexually antagonistic alleles are the more likely explanation.
The genome of Erwinia tasmaniensis strain Et1/99, a non‐pathogenic bacterium in the genus Erwinia
Authors: Kube Michael , Migdoll Alexander Michael , Müller Ines , Kuhl Heiner , Beck Alfred , Reinhardt Richard , Geider Klaus 
Published: May 2008

SummaryThe complete genome of the bacterium Erwinia tasmaniensis strain Et1/99 consisting of a 3.9 Mb circular chromosome and five plasmids was sequenced. Strain Et1/99 represents an epiphytic plant bacterium related to Erwinia amylovora and E. pyrifoliae, which are responsible for the important plant diseases fire blight and Asian pear shoot blight, respectively. Strain Et1/99 is a non‐pathogenic bacterium and is thought to compete with these and other bacteria when occupying the same habitat during initial colonization. Genome analysis revealed tools for colonization, cellular communication and defence modulation, as well as genes coding for the synthesis of levan and a not detected capsular exopolysaccharide. Strain Et1/99 may secrete indole‐3‐acetic acid to increase availability of nutrients provided on plant surfaces. These nutrients are subsequently accessed and metabolized. Secretion systems include the hypersensitive response type III pathway present in many pathogens. Differences or missing parts within the virulence‐related factors distinguish strain Et1/99 from pathogens such as Pectobacterium atrosepticum and the related Erwinia spp. Strain Et1/99 completely lacks the sorbitol operon, which may also affect its inability to invade fire blight host plants. Erwinia amylovora in contrast depends for virulence on utilization of sorbitol, the dominant carbohydrate in rosaceous plants. The presence of other virulence‐associated factors in strain Et1/99 indicates the ancestral genomic background of many plant‐associated bacteria.
Fibrosis correlates with detailed histological analysis of human undescended testes
Authors: Suskind Anne , Hayner‐Buchan Alida , Feustel Paul J. , Kogan Barry A. 
Published: May 2008

OBJECTIVETo evaluate whether semiquantitatively assessing the histological degree of fibrosis provides equivalent information to a detailed histological analysis of undescended testes in children.PATIENTS AND METHODSWe reviewed retrospectively the histological and clinical data from 86 consecutive orchidopexies. Biopsies fixed in Bouin’s solution were evaluated histologically for tubular diameter, germ cell number and fibrosis. Fibrosis was assessed semiquantitatively by a pathologist reviewing sections stained with Masson’s trichrome. The median (range) age of the patients was 1.9 (0.5–13.5) years, with 29 aged <1 year and 57 aged >1 year.RESULTSThere were 65 palpable and 21 impalpable testes; 62 were inguinal and 13 were intra‐abdominal. Testicular biopsies showed smaller tubules and fewer germ cells in patients aged >1 year, but there were no significant differences based on the location of the testis on physical examination or at the time of operation. The amount of fibrosis correlated well with tubular diameter and germ cell counts.CONCLUSIONFibrosis can be assessed easily and correlates well with more complex forms of histological evaluation of testicular health in children.
Clitoral sexual arousal: an immunocytochemical and innervation study of the clitoris
Authors: Martin‐Alguacil Nieves , Pfaff Donald W. , Shelley Deborah N. , Schober Justine M. 
Published: May 2008

OBJECTIVETo further define neural pathways and mechanisms responsible for the arousing properties of the epithelium of the clitoris as well as related neural pathways associated with sexual arousal in a murine model.MATERIALS AND METHODSAdult female C57B1/6 mice were used for gross dissection, facilitated by resin injection of the vascular system, and silver staining, and immunostaining for S‐100 and neuronal nitric oxide synthase (nNOS). We also comprehensively reviewed relevant published clinical and histological material from both human and non‐human vertebrate studies.RESULTSThe distal innervation consists of three nerve bundles: one related to the perineal region, one through the corpus cavernosum, and the third between the dorsal part of the clitoris and the urethra. Communicating nerve fibres were identified between the perineal, the corpus cavernous nerve (CN) and the dorsal nerve of the clitoris. Immunostaining for nNOS showed that the CN sends nNOS‐positive fibres to join the dorsal nerve of the clitoris. In the same distal area of the clitoris, the connecting branches between the perineal nerve and the dorsal nerve of the clitoris are also nNOS positive.CONCLUSIONSA rich network of nerve bundles and terminal branches were identified and associated with nNOS immunostaining in the cavernosal tissue of the body of clitoris. NO control of vasodilatation and neuronal signalling between the CN and the dorsal nerve of the clitoris could contribute to the engorgement and subsidence of clitoral tissue. This supports the initiation of sexual arousal by tactile stimuli. The distribution pattern of the general and peptidergic innervation in the murine clitoris is similar to that of the penis.
Earnings persistence, accruals and managerial share ownership
Authors: Oei Rosalyn , Ramsay Alan , Mather Paul 
Published: May 2008

AbstractWe investigate the relationship between earnings persistence and a broad measure of total accruals (TACC). We propose and find that in Australia, TACC is less persistent than cash flows. We further propose that the persistence of accrual components is positively associated with the reliability of those components. However, we find that the least reliable accrual component has the greatest persistence and suggest possible reasons for this. We then investigate the relationship between earnings persistence and managerial share ownership, but find no evidence of a consistent, strong relationship. Rather, for the non‐current operating accruals we find evidence consistent with incentive alignment for large firms with high operating cash flows, whereas for small firms we find evidence consistent with efficient contracting.
Cost of capital equations under the Australian imputation tax system
Authors: Dempsey Mike , Partington Graham 
Published: May 2008

AbstractSince the introduction of the Australian imputation tax system, there have been problems both in the measurement of the market value of franking (imputation tax) credits and in their application to estimating cash flows and the cost of capital. In the present paper, we provide a convenient and robust resolution to the above problems in the context of an internally consistent set of equations for the cost of capital, asset valuation and the capital asset pricing model (CAPM). The equations apply under both classical and imputation tax systems and under differential taxation of dividends, capital gains and interest. The simple form of the CAPM presented here is shown to encompass more complex versions of the CAPM, which attempt to accommodate the effect of personal taxes. The valuation equations require an estimate of the market value of $1 of the firm's dividends, within which is embedded the market value of the imputation tax credits. Separate estimates of the value of imputation tax credits, or Officer's gamma factor, are not required.
Auditor reporting and earnings management: some additional evidence
Authors: Herbohn Kathleen , Ragunathan Vanitha 
Published: May 2008

AbstractThis paper investigates the reasons that lead to modification of auditors’ opinions. We revisit the conclusions of prior US‐based research on whether a modification highlights likely earnings management activities. Extending this research, we consider an alternate explanation that managers adjust accruals to report earnings that better predict future firm performance, which has the side‐effect of placing them in conflict with their auditors. Our study sample comprises all firms listed on the Australian Stock Exchange over the period 1999–2003. Consistent with prior research, there is no evidence of earnings management leading to an audit opinion modification. However, we do show that firms receiving inherent uncertainty modifications (other than going concern) have greater persistence of earnings (accruals) relative to other firms. This is consistent with the proposition that managers have made policy choices in reporting current earnings, with which their auditors disagree, that will likely result in a greater ability to forecast the firm's future earnings.
Speed of word recognition and vocabulary knowledge in infancy predict cognitive and language outcomes in later childhood
Authors: Marchman Virginia A. , Fernald Anne 
Published: May 2008

Abstract The nature of predictive relations between early language and later cognitive function is a fundamental question in research on human cognition. In a longitudinal study assessing speed of language processing in infancy,

Fernald, Perfors and Marchman (2006

) found that reaction time at 25 months was strongly related to lexical and grammatical development over the second year. In this follow‐up study, children originally tested as infants were assessed at 8 years on standardized tests of language, cognition, and working memory. Speed of spoken word recognition and vocabulary size at 25 months each accounted for unique variance in linguistic and cognitive skills at 8 years, effects that were attributable to strong relations between both infancy measures and working memory. These findings suggest that processing speed and early language skills are fundamental to intellectual functioning, and that language development is guided by learning and representational principles shared across cognitive and linguistic domains.
Intergenerational transmission of theory‐of‐mind
Authors: Sabbagh Mark A. , Seamans Elizabeth L. 
Published: May 2008

AbstractWe examined whether individual differences in children's performance on a scaled battery of theory‐of‐mind tasks was predicted by parents’ performance on an adult theory‐of‐mind task. Forty‐six 3‐year‐old children and their parents participated in this study when children were aged 2;11 to 4;0. Thirty dyads returned 6 months later for a second assessment. After statistically controlling for relevant covariates, we detected a positive correlation between parents’ and children's theory‐of‐mind scores. The correlation was significant at both time points, and was robust when data were aggregated across the two sessions. These results provide some evidence for intergenerational transmission of theory‐of‐mind abilities in a typically developing sample, and possible mechanisms underlying this relation are discussed.