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We report the fabrication of devices in which one single-walled carbon nanotube spans a barrier between two fluid reservoirs, enabling direct electrical measurement of ion transport through the tube. A fraction of the tubes pass anomalously high ionic currents. Electrophoretic transport of small single-stranded DNA oligomers through these tubes is marked by(More)
In the recent issue of PNAS, Futrell et al. claims that their study of 37 languages gives the first large scale cross-language evidence for Dependency Length Minimization, which is an overstatement that ignores similar previous researches. In addition,this study seems to pay no attention to factors like the uniformity of genres, which weakens the validity(More)
In typological studies on word order, the linear order of the grammatical units in a sentence is often used as the primary way to distinguish one language from another. Greenberg (1963) is generally considered as the initiator of this field. 1 Greenberg proposed 45 linguistic universals. Twenty-eight of these universals touch on the order or position of(More)
Pestalafuranones A-E (compounds 1-5), five new 2(5H)-furanones, have been isolated from cultures of an isolate of Pestalotiopsis besseyi. The structures of these compounds were elucidated mainly by analysis of their NMR spectroscopic data and HRESIMS experiments. Pestalafuranones A-C (compounds 1-3) displayed weak inhibitory effects against HIV-1(More)
In the past decades, regional air pollution characterized by photochemical smog and grey haze-fog has become a severe environmental problem in China. To investigate this, a field measurement campaign was performed in the Huabei region, located between 32–42 • N latitude in eastern China, during the period 2 April–16 May 2006 as part of the project "(More)
Feature selection is of great importance in recognition system design because it directly affects the overall performance of the recognition system. Feature selection can be considered as a problem of global combinatorial optimization. It is a very time-consuming task in order to search the most suitable features amongst a huge number of possible feature(More)
The phenomenon of extraordinary light transmission through metallic films perforated by nanohole arrays at optical frequencies was first observed a decade ago and initiated important further experimental and theoretical work. In view of potential applications of such structures--for example, subwavelength optics, optoelectronics devices, and chemical(More)
Mixing dependency lengths from sequences of different length is a common practice in language research. However, the empirical distribution of dependency lengths of sentences of the same length differs from that of sentences of varying length. The distribution of dependency lengths depends on sentence length for real sentences and also under the null(More)