bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the phylogenetic position of Gogonasus andrewsae Long 1985, within the Tetrapodomorpha
Authors: Holland Timothy , Long John A. 
Published: May 2009

AbstractWithin the Tetrapodomorpha, the Late Devonian Gogonasus andrewsae of the Gogo Formation, Gogo, Western Australia, has occupied an uncertain phylogenetic position. Following the description of several well‐preserved three‐dimensional skulls and pectoral girdles, the discovery of the first complete specimen (NMV P221807) made Gogonasus one of the best‐known tetrapodomorph fish. Recent studies of pectoral fin structure and the spiracular opening of Gogonasus have suggested an unexpected affinity with ‘elpistostegalid’ fish such as Tiktaalik. Subsequent work has refuted characters linking these taxa, with phylogenetic analysis of the Tetrapodomorpha placing Gogonasus basal to megalichthyids and tristichopterids. In this paper we reanalyse characters linking Gogonasus with ‘elpistostegalid’ fish and those supporting the placement of Gogonasus crownward of Eusthenopteron. New phylogenetic analyses of the Tetrapodomorpha show a revised phylogenetic position of Gogonasus as being deeply nested within the Tetrapodomorpha, crownward of Osteolepis and Megalichthys, but basal to Eusthenopteron+‘elpistostegalids’. Functional consideration of the spiracular structure suggests a position of Gogonasus closer to ‘elpistostegalids’, although data is lacking from other less‐well‐preserved taxa to fully test the hypothesis. The humerus of the Late Devonian lungfish Chirodipterus from Gogo, Western Australia is figured for comparative purposes.
Cell fate and timing in the evolution of neural crest and mesoderm development in the head region of amphibians and lungfishes
Authors: Ericsson Rolf , Ziermann Janine M. , Piekarski Nadine , Schubert Grit , Joss Jean , Olsson Lennart 
Published: May 2009

AbstractOur research on the evolution of head development focuses on understanding the developmental origins of morphological innovations and involves asking questions like: How flexible (or conserved) are cell fates, patterns of cell migration or the timing of developmental events (heterochrony)? How do timing changes, or changes in life history affect head development and growth? Our ‘model system’ is a comparison between lungfishes and representatives from all three extant groups of amphibians. Within anuran amphibians, major changes in life history such as the repeated evolution of larval specializations (e.g. carnivory), or indeed the loss of a free‐swimming larva, allows us to test for developmental constraints. Cell migration and cell fate are conserved in cranial neural crest cells in all vertebrates studied so far. Patterning and developmental anatomy of cranial neural crest and head mesoderm cells are conserved within amphibians and even between birds, mammals and amphibians. However, the specific formation of hypobranchial muscles from ventral somitic processes shows variation within tetrapods. The evolution of carnivorous larvae in terminal taxa is correlated with changes in both pattern and timing of head skeletal and muscle development. Sequence‐heterochronic changes are correlated with feeding mode in terminal taxa and with phylogenetic relatedness in basal branches of the phylogeny. Eye muscles seem to form a developmental module that can evolve relatively independently from other head muscles, at least in terms of timing of muscle differentiation.
Agnathan brain anatomy and craniate phylogeny
Authors: Khonsari Roman Hossein , Li Blaise , Vernier Philippe , Northcutt R. Glenn , Janvier Philippe 
Published: May 2009

AbstractThe central nervous system of hagfishes displays unique characteristics that are distinct from any other craniate neuroanatomic features. Whether these hagfish characters are general for all craniates, autapomorphies of hagfishes, or merely a derived state of the general cyclostome condition is still a matter of debate that relates to the question of the monophyly or paraphyly of the cyclostomes. The present cladistic study includes 123 neuroanatomical characters of nine chordate species and supports cyclostome paraphyly, in contrast to most current molecular sequence‐based phylogenies, which support cyclostome monophyly. An understanding of the unique neural characters in hagfishes is critical to inspiring further comparative and developmental studies with regards to these two conflicting results and the very deep divergence between craniates and their presumed sister groups. The recent access to hagfish developmental data may provide exciting perspectives in the understanding and characterization of the basalmost craniate node and the interpretation of hagfish brain structure.
The humerus of Panderichthys in three dimensions and its significance in the context of the fish–tetrapod transition
Authors: Boisvert Catherine A. 
Published: May 2009

AbstractThe humerus of Panderichthys has been considered to represent a transitional form between that of tetrapodomorph fish such as Eusthenopteron and tetrapods such as Acanthostega. The previous description was based on flattened material and was analysed in the context of the few fossils known at the time. Since then, several new forms have been described such as Gogonasus, Tiktaalik and an isolated humerus from the Catskill Formation. The humeral morphology of Panderichthys rhombolepis and its interpretation in this new context are therefore reassessed with the help of a three‐dimensional model produced with the mimics software based on a computed tomography scan of an unflattened specimen as well as comparisons with the originally described material. The humerus of Panderichthys displays a combination of primitive, derived, intermediate and unique characteristics. It is very similar to the morphology of Tiktaalik but when it differs from it, it is most often more derived despite the more basal phylogenetic position that Panderichthys occupies. What emerges from this study is a much more gradual transformation of the humerus morphology from fish to tetrapods and the ability to distinguish autapomorphies more easily. The picture is more complex than previously believed, with many morphological specializations probably reflecting the breadth of ecological specializations already present at the time.
Things to Do Today . . . : A Daily Diary Study on Task Completion at Work
Authors: Claessens Brigitte J.C. , Van Eerde Wendelien , Rutte Christel G. , Roe Robert A. 
Published: May 2009

Relatively little is known about how goals in complex jobs are translated into action and how they are completed in real life settings. This study addressed the question to what extent planned work may actually be completed on a daily basis. The completion of daily work goals was studied in a sample of 878 tasks identified by 29 R&D engineers with the help of a daily diary. Multilevel analysis was used to analyse the joint effect of task attributes, perceived job characteristics, and personality attributes on the completion of planned work goals. At the level of task attributes, we found that priority, urgency, and lower importance were related to task completion, and at the individual level, conscientiousness, emotional stability, and time management training. Task completion was not related to task attractiveness, workload, job autonomy, planning, or perceived control of time.On connaît relativement peu de choses sur la manière dont les objectifs dans des tâches complexes sont traduites en action et sur la manière dont elles sont accomplies dans le cadre de la vie quotidienne. Cette étude a abordé la question de savoir dans quelle mesure les travaux prévus peuvent être effectivement achevés dans la vie quotidienne. Pour ce faire, un échantillon de 878 tâches a été identifié par 29 ingénieurs R&D à l’aide d’un journal quotidien. Une analyse multi niveau a été réalisée pour étudier l’effet conjoint des caractéristiques de la tâche et des caractéristiques de la personnalité sur l’accomplissement des objectifs d’un travail planifié. Au niveau des caractéristiques de la tâche, nous trouvons que l’accomplissement de la tâche est liéà la priorité, l’urgence et une importance basse et au niveau individuel à la conscience, la stabilitéémotionnelle et à la gestion du temps. L’accomplissement de la tâche n’est pas liéà son attrait, à la charge de travail, à l’autonomie au travail ou au contrôle du temps perçu.
Do uninformed crossed and internalized trades tap into unexpressed liquidity? The case of Nokia
Authors: Westerholm P. Joakim 
Published: May 2009

AbstractCrossed and internalized upstairs trades are analysed in a dataset in which institutional investors can be identified. Earlier findings that upstairs trading is uninformed, taps into unexpressed liquidity, and does not affect market quality are revisited. The permanent price effect of crossings and internalized upstairs trades is significantly lower than that of limit order book trades due to the fact that the least informed institutional trades are routed upstairs. Crossed and internalized trades affect the depth and transaction costs in the limit order book and a greater reliance is placed on the upstairs market when liquidity is low and volatility is high.
Effect of ownership structure on underinvestment and overinvestment: empirical evidence from Spain
Authors: Pindado Julio , De La Torre Chabela 
Published: May 2009

AbstractThis paper investigates how ownership affects the investment‐cash flow sensitivity by taking into account the non‐linearities of ownership with respect to firm value, and using a free cash flow index and a criterion for financial constraints to disentangle underinvestment and overinvestment. Interesting results are provided by estimating using the Generalized Method of Moments to eliminate the endogeneity problem. The alignment of interests between owners and managers and the monitoring by concentrated ownership both alleviate the sensitivity of investment to cash flow both in underinvestor and overinvestor firms. However, in the presence of controlling owners, underinvestment and overinvestment are exacerbated.
Information and volatility links in the foreign exchange market
Authors: Treepongkaruna Sirimon , Gray Stephen 
Published: May 2009

AbstractWe apply the trading model of Fleming et al (1998). to a number of currency markets. The model posits that two markets can have common volatility structures as a result of receiving common information and from cross‐hedging activity where a position in one currency is used to hedge risk in a position taken in another. Our results imply that the model is effective in identifying common information flows and volatility spillovers in the currency markets and that some of these effects are lost when simply examining raw correlations. A series of specification tests of the 21 bivariate systems that are examined provides support for the trading model in the foreign exchange context.
Impact of earnings performance on price‐sensitive disclosures under the Australian continuous disclosure regime
Authors: Hsu Grace Chia‐Man 
Published: May 2009

AbstractThis study examines the relation between accounting earnings and the frequency of price‐sensitive corporate disclosure under Australia's statutory continuous disclosure requirements. Despite low litigation threats and excepting loss‐making firms, results show that firms with earnings declines (bad news) are more likely to make continuous disclosure than firms with earnings increases (good news). This suggests that market forces and regulators’ scrutiny are sufficient to induce a ‘bad news’ disclosure bias. This study also examines the ‘materiality’ requirement under the continuous disclosure requirements and finds a positive relation between disclosure frequency and the magnitude of earnings news. The earnings–return correlation is positively associated with disclosure frequency for the financial services industry.
Alternative event study methodology for detecting dividend signals in the context of joint dividend and earnings announcements
Authors: Anderson Warwick 
Published: May 2009

AbstractFriction models are used to examine the market reaction to the simultaneous disclosure of earnings and dividends in a thin‐trading environment. Friction modelling, a procedure using maximum likelihood estimation, can be used to replace both the market model and restricted least‐squares regression in event studies where there are two quantifiable variables and a number of possible interaction effects associated with the news that constitutes the study's event. The results indicate that the dividend signal can be separated from the earnings signal.
Do Birds of a Feather Flock Higher? The Effects of Partner Similarity on Innovation in Strategic Alliances in Knowledge‐Intensive Industries
Authors: Luo Xiaowei , Deng Lina 
Published: May 2009

abstractIn spite of the consensus on the benefits of strategic alliances for learning and innovation, our understanding of the effects of partner similarity remains conflicted. This paper develops an integrative theoretical framework in which we propose that similar partners in a focal firm's alliance portfolio contribute to the firm's innovation up to a threshold, beyond which additional similar partners can lead to a decrease in innovation because of the trade‐offs embedded in collaboration between similar partners. In this integrative framework, we also draw on organizational ecology and institutional perspectives to propose that the effect of partner similarity on innovation is positively moderated by organizational aging and the industry norm of collaboration at the firm's founding. Results from an analysis of 176 biotechnology firms between 1988 and 1999 support our arguments. This study contributes to research on strategic alliance and innovation by considering both the benefits and costs of partner similarity in the context of alliance portfolios and by exploring the multilevel contingencies for the effects of partner similarity.
Bacterial formation of phosphatic laminites off Peru
Authors: ARNING E. T. , BIRGEL D , BRUNNER B , PECKMANN J 
Published: May 2009

AbstractAuthigenic phosphatic laminites enclosed in phosphorite crusts from the shelf off Peru (10°01′ S and 10°24′ S) consist of carbonate fluorapatite layers, which contain abundant sulfide minerals including pyrite (FeS2) and sphalerite (ZnS). Low δ34Spyrite values (average −28.8‰) agree with bacterial sulfate reduction and subsequent pyrite formation. Stable sulfur isotopic compositions of sulfate bound in carbonate fluorapatite are lower than that of sulfate from ambient sea water, suggesting bacterial reoxidation of sulfide by sulfide‐oxidizing bacteria. The release of phosphorus and subsequent formation of the autochthonous phosphatic laminites are apparently caused by the activity of sulfate‐reducing bacteria and associated sulfide‐oxidizing bacteria. Following an extraction–phosphorite dissolution–extraction procedure, molecular fossils of sulfate‐reducing bacteria (mono‐O‐alkyl glycerol ethers, di‐O‐alkyl glycerol ethers, as well as the short‐chain branched fatty acids i/ai‐C15:0, i/ai‐C17:0 and 10MeC16:0) are found to be among the most abundant compounds. The fact that these molecular fossils of sulfate‐reducing bacteria are distinctly more abundant after dissolution of the phosphatic laminite reveals that the lipids are tightly bound to the mineral lattice of carbonate fluorapatite. Moreover, compared with the autochthonous laminite, molecular fossils of sulfate‐reducing bacteria are: (1) significantly less abundant and (2) not as tightly bound to the mineral lattice in the other, allochthonous facies of the Peruvian crusts consisting of phosphatic coated grains. These observations confirm the importance of sulfate‐reducing bacteria in the formation of the phosphatic laminite. Model calculations highlight that organic matter degradation by sulfate‐reducing bacteria has the potential to liberate sufficient phosphorus for phosphogenesis.
CaCO3 nucleation by cyanobacteria: laboratory evidence for a passive, surface‐induced mechanism
Authors: OBST M. , WEHRLI B. , DITTRICH M. 
Published: May 2009

AbstractCalcite nucleation on the surface of cyanobacteria of the Synechococcus leopoliensis strain PCC 7942 was investigated to assess the influence of photosynthetic uptake of inorganic carbon and active ion exchange processes across the cell membrane on the nucleation and precipitation mechanisms. We performed long‐term precipitation experiments at a constant CO2 level in ambient air by adding suspensions of previously washed cyanobacteria to solutions of NaHCO3/CaCl2 which were supersaturated with respect to calcite. Induction times between 4 and 110 h were measured over a range of saturation states, Ω, between 8 and 4. The kinetics of CaCO3 nucleation was compared between experiments: (i) with ongoing photosynthesis, (ii) with cells metabolizing but not undergoing photosynthetic uptake of inorganic carbon and (iii) in darkness without photosynthesis. No significant differences were observed between the three treatments. The results reveal that under low nutrient concentrations and permanent CO2 supply, photosynthetic uptake of inorganic carbon predominantly uses CO2 and consequently does not directly influence the nucleation process of CaCO3 at the surface of S. leopoliensis. Furthermore, ion exchange processes did not affect the kinetics, indicating a passive nucleation process wherein the cell surface or extracellular polymers provided preferential sites for mineral nucleation. The catalyzing effect of the cyanobacteria on calcite nucleation was equivalent to a ∼18% reduction in the specific interfacial free energy of the calcite nuclei. This result and the ubiquitous abundance of cyanobacteria suggest that this process may have an impact on local and global carbon cycling.
Expression of distinct α1‐adrenoceptor phenotypes in the iris of pigmented and albino rabbits
Authors: Muramatsu I , Suzuki F , Nishimune A , Anisuzzaman ASM , Yoshiki H , Su T‐H , Chang C‐K , Morishima S 
Published: May 2009

Background and purpose: The expression of multiple pharmacological phenotypes including α1L‐adrenoceptor has recently been reported for α1‐adrenoceptors. The purpose of the present study was to identify α1‐adrenoceptor phenotypes in the irises of pigmented and albino rabbits.Experimental approach: Radioligand binding and functional bioassay experiments were performed in segments or strips of iris of pigmented and albino rabbits, and their pharmacological profiles were compared.Key results: [3H]‐silodosin at subnanomolar concentrations bound to intact segments of iris of pigmented and albino rabbits at similar densities (approximately 240 fmol·mg−1protein). The binding sites in the iris of a pigmented rabbit were composed of a single component showing extremely low affinities for prazosin, hydrochloride [N‐[2‐(2‐cyclopropylmethoxyphenoxy)ethyl]‐5‐chloro‐α,α‐dimethyl‐1H‐indole‐3‐ethamine hydrochloride (RS‐17053)] and 5‐methylurapidil, while two components with high and low affinities for prazosin, RS‐17053 and 5‐methylurapidil were identified in irises from albino rabbits. In contrast, specific binding sites for [3H]‐prazosin were not clearly detected because a high proportion of non‐specific binding and/or low affinity for prazosin occurred. Contractile responses of iris dilator muscle to noradrenaline were antagonized by the above ligands, and their antagonist affinities were consistent with the binding estimates at low‐affinity sites identified in both strains of rabbits.Conclusions and implications: A typical α1Lphenotype with extremely low affinity for prazosin is exclusively expressed in the iris of pigmented rabbits, while two distinct phenotypes (α1Aand α1L) with high and moderate affinities for prazosin are co‐expressed in the iris of albino rabbits. This suggests that a significant difference in the expression of phenotypes of the α1‐adrenoceptor occurs in the irises between the two strains of rabbits.
The effect of previous pregnancy and transfusion on HLA alloimmunization in blood donors: implications for a transfusion‐related acute lung injury risk reduction strategy
Authors: Triulzi Darrell J. , Kleinman Steven , Kakaiya Ram M. , Busch Michael. P. , Norris Philip J. , Steele Whitney R. , Glynn Simone A. , Hillyer Christopher D. , Carey Patricia , Gottschall Jerome L. , Murphy Edward L. , Rios Jorge A. , Ness Paul M. , Wright David J. , Carrick Danielle , Schreiber George B. 
Published: May 2009

BACKGROUND: Antibodies to human leukocyte antigens (HLA) in donated blood have been implicated as a cause of transfusion‐related acute lung injury (TRALI). A potential measure to reduce the risk of TRALI includes screening plateletpheresis donors for HLA antibodies. The prevalence of HLA antibodies and their relationship to previous transfusion or pregnancy in blood donors was determined.STUDY DESIGN AND METHODS: A total of 8171 volunteer blood donors were prospectively recruited by six US blood centers from December 2006 to May 2007. Donors provided a detailed history of pregnancy and transfusion and a sample for HLA Class I and II antibody testing by multiantigen bead flow analysis.RESULTS: A total of 8171 donors were enrolled; 7920 (96.9%) had valid HLA antibody test results and 7841 (99%) of those had complete pregnancy and transfusion information. The prevalence of any HLA antibody was similar in nontransfused (n = 1138) and transfused (n = 895) men, 1.0% versus 1.7% (p = 0.16). HLA antibodies were detected in 17.3% of all female donors (n = 5834) and in 24.4% of those with a history of previous pregnancy (n = 3992). The prevalence of HLA antibodies increased in women with greater numbers of pregnancy: 1.7% (zero), 11.2% (one), 22.5% (two), 27.5% (three), and 32.2% (four or more pregnancies; p < 0.0001).CONCLUSION: HLA Class I and Class II antibodies are detectable at low prevalence in male donors regardless of transfusion and in female donors without known immunizing events. The prevalence of HLA antibodies increases significantly with more pregnancies. These data will allow blood centers to estimate the impact of HLA antibody testing as a potential TRALI risk reduction measure.
Kit K641E oncogene up‐regulates Sprouty homolog 4 and Trophoblast glycoprotein in interstitial cells of Cajal in a murine model of gastrointestinal stromal tumours
Authors: Gromova Petra , Ralea Sebastian , Lefort Anne , Libert Frédérick , Rubin Brian P , Erneux Christophe , Vanderwinden Jean‐Marie 
Published: May 2009

AbstractGastrointestinal stromal tumours (GIST) are thought to derive from the interstitial cells of Cajal (ICC) or an ICC precursor. Oncogenic mutations of the receptor tyrosine kinase KIT are present in most GIST. KIT K642E was originally identified in sporadic GIST and later found in the germ line of a familial GIST cohort. A mouse model harbouring a germline Kit K641E mutant was created to model familial GIST. The expression profile was investigated in the gastric antrum of the KitK641E murine GIST model by microarray, quantitative PCR and immunofluorescence. Gja1/Cx43, Gpc6, Gpr133, Pacrg, Pde3a, Prkar2b, Prkcq/Pkce, Rasd2, Spry4 and Tpbg/5T4 were found to be up‐regulated. The proteins encoded by Gja1/Cx43, Pde3a, Prkcq/Pkce were localized in Kit‐ir ICC in wild‐type and KitK641E animals while Spry4 and Tpbg/5T4 were detected in Kit‐ir cells only in KitK641E, but not in KitWT/WT animals. Most up‐regulated genes in this mouse model belong to the gene expression profile of human GIST but also to the profile of normal Kit+ ICC in the mouse small intestine. Spry4 and Tpbg/5T4 may represent candidates for targeted therapeutic approaches in GIST with oncogenic KIT mutations.