187,343 research outputs found
Variegated VC Rime Restrictions in Sinitic Languages
No full textIn this study, we consider a non-Markedness-based account for VC rime phonotactics in Sinitic languages, with special reference to Taiwanese Southern Min and Hakka. Rime gaps in Chinese languages have been customarily analyzed as co-occurrence markedness constraints. But analyses along this line not only overgenerate by predicting unattested gaps, but also fail to motivate those phonotactic constraints in a principled fashion. By adopting Hsieh\u27s (2010) duration-based account, we present further phonetic evidence to show that phonotactics of Chinese VC combinations may be attributed to: (i) low perceptibility of coda consonants due to absence of release, and (ii) decreased vowel distinctiveness as a result of vowel reduction. One of the new findings in this study is that the perceptual difficulties are further exacerbated by the relatively shorter duration of Taiwanese checked syllables, if compared with those of Hakka and Cantonese. Also, salient F2 transitions (vowel gliding) may occur to enhance the place of articulation of a stop coda in Taiwanese. Therefore, rime gaps are normally found in contexts whereby (i) VC coarticulation is weak and (ii) vowel distinctiveness cannot be maintained. In sum, the results of our acoustic studies suggest that the duration-based approach offers a more straightforward account for why Taiwanese has more rime gaps than Hakka and Cantonese do
Shear transfer mechanism in reinforced engineered cementitious composite (ECC) beams: Quantification of Vs and Vc
No full textTo enhance the structural and seismic resistance, as well as durability of concrete structures, an ultra ductile fiber reinforced cementitious composites called Engineered Cementitious Composite (ECC), also known as Strain Hardening Cementitious Composite (SHCC), was developed. ECC has a similar compressive and tensile strength to conventional concrete, but it exhibits a pseudo-strain-hardening behaviour under uniaxial tension with excellent crack control ability. The ultimate tensile strain of ECC can reach 3–12%, which is 300–1200 times higher than that of concrete. It is reported that ECC can also exhibit at least twice as high shear carrying capacity compared to traditional concrete, signifying a potential to use ECC material in shear-resistance elements. However, the shear resisting mechanism of reinforced ECC (R/ECC) members is still not clear. In most existing codes and models, the shear strength of reinforced structural members (Vu) is divided into two parts, i.e., shear resistance coming from the matrix (Vc) and from the transverse reinforcement (Vs). To quantify accurately Vc and Vs and also their development throughout the loading, a well-designed testing method consisting of continuous strain quantification along the stirrups, was used in this research. Six steel reinforced beams incorporating different matrix (ECC, concrete and mortar) were tested under four-point bending. The test results indicated that Vc changed continuously with the propagation of shear crack, whereas the stirrups that crossed the critical shear crack, did not always yield at the ultimate shear resistance.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Concrete Structure
Venture Capital, Ownership Concentration and Enterprise R&D Investment
No full textAbstractWe empirically examine the relationship among venture capital (VC), ownership concentration and enterprise R&D investment. Drawing on the data of China's GEM from 2010 to 2014, we find that VC and enterprise R&D investment are significantly positively correlated while ownership concentration and enterprise R&D investment are significantly negatively correlated. Further research shows that in the VC-backed companies ownership concentration has no significant impact on R&D investment
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The Japanese financial market: evidence on firm financing choice and investment after deregulation
No full textMarket Potential and Operational Scenarios for Virtual Coupling
No full textThis document evaluates the attractiveness of Virtual Coupling (VC) for different market segments (high-speed, main line, regional, urban/suburban, freight) and defines operational scenarios for each of them. A SWOT analysis identifies main strengths and weaknesses of the Virtual Coupling concept and corresponding opportunities and threats to each specific railway market segment. The research relies on a Delphi method with an extensive survey of expert opinions and stated travel preferences assuming VC has been implemented. The survey involved subject matter experts of the wide European railway industry including infrastructure managers, railway undertakings, system suppliers, transport authorities, railway institutions, private consultants and academics. In addition, travel preferences have been collected by interviewing European representatives belonging to other socio professional categories. Results show that the implementation of Virtual Coupling can be attractive to customers of high-speed, main line, regional and especially freight segments. Virtual Coupling has the potential of completely changing the way in which such segments operate and attract a modal shift from other transport modes to railways. Customers are even willing to pay higher fares for more frequent and flexible train services, especially on the regional and freight segments which are currently perceived as not satisfactory. Several operational scenarios have been defined based on the outcomes of the survey, setting market-attractive VC service headways for each market segment as well as specifying characteristics of rolling stock, power supply, traffic, and platform crowd management. Principles to couple/decouple convoys of virtually coupled trains are also provided based on the specific network characteristics of the different market segments.A SWOT analysis is presented which builds on the outcomes of the survey, the operational scenarios and brainstorming sessions with experts of the European railway industry. The main strengths identified for VC are a substantial increase in capacity and reduced operational costs with respect to Moving Block while mitigating delay propagation and improving reliability of ground/train communication. On the other hand, weaknesses of this concept refer to the fact that capacity gains at diverging junctions equipped with current switch technologies might be marginal, since here trains still need to be separated by a full braking distance. Also, the implementation of VC operations would require an investment to upgrade the overhead line system, platform lengths (to allow platoons of trains to stop) and possibly the switch technology. An upgrade of the switch technology towards faster and more reliable ones (e.g. Railtaxi and REPOINT) will unleash the full potential of VC operations. Significant opportunities will be brought about Virtual Coupling such as potential increase in the profit of infrastructure managers and operators as well as a deregulation of the current railway market which could be opened also to smaller transport operators due to the increase of available train paths and the decrease of operational costs by full train automation. In addition, the train-to-train communication could lead to the institution of cooperative consortia of railway operators which can be more economically beneficial than the current competitive market model. This would also provide the chance to migrate obsolescent command and control systems towards future-proof digital railway architectures. Possible threats to the introduction of this concept mainly relate to potential increase of train control complexity increasing risks of approval from the railway industry. The need for an initial investment might be not well received by infrastructure managers and local governments. As well as the necessity of partially changing policies, operational procedures and engineering rules currently in place. When overcoming such challenges, Virtual Coupling has potentials to fully revolutionise and improve current train operations so to induce a sustainable shift to railways.Transport and Plannin
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Ectopic EBP2 expression enhances cyclin E1 expression and induces chromosome instability in HEK293 stable clones.
No full textDirect observation of spin-polarized surface states in the parent compound of a topological insulator using spin- and angle-resolved photoemission spectroscopy in a Mott-polarimetry mode
No full textWe report high-resolution spin-resolved photoemission spectroscopy (spin-ARPES) measurements on the parent compound Sb of the recently discovered three-dimensional topological insulator Bi1−xSbx (Hsieh et al 2008 Nature 452 970, Hsieh et al 2009 Science 323 919). By modulating the incident photon energy, we are able to map both the bulk and the (111) surface band structure, from which we directly demonstrate that the surface bands are spin polarized by the spin–orbit interaction and connect the bulk valence and conduction bands in a topologically non-trivial way. A unique asymmetric Dirac surface state gives rise to a k-splitting of its spin-polarized electronic channels. These results complement our previously published works on this class of materials and re-confirm our discovery of topological insulator states in the Bi₁₋ₓSbₓ series
- …
