6,349 research outputs found
International and Intra-national Technology Spillovers and Technology Development Paths in Developing Countries: The Case of China
This paper analyses the paths of technology development among regions with heterogeneous economic and technological characteristics, focusing on the case of China. It finds that intra-national technology transfer, that is, the technology transfer from technologically advanced provinces to less advanced ones, is more important than that taking place through FDI in the backward regions. In technologically advanced areas, learning by doing, indigenous R&D and technology transfer from FDI all play a significant role in technical progress. The relationship between the strength of interprovincial technology transfer and technological distance is U-shaped, with the technology threshold falling outside the upper bound of technology distance. This suggests that technology transfer takes place more effectively when technological distance is small. The paper finds that learning by doing and R&D are important internal routes to technical progress. R&D plays a key role in the assimilation of foreign technologies, whereas learning by doing is relevant for the absorption of interprovincial technology transfers.FDI, technology spillovers, technology threshold
Entangling a series of trapped ions by moving cavity bus
Entangling multiple qubits is one of the central tasks for quantum
information processings. Here, we propose an approach to entangle a number of
cold ions (individually trapped in a string of microtraps) by a moved cavity.
The cavity is pushed to include the ions one by one with an uniform velocity,
and thus the information stored in former ions could be transferred to the
latter ones by such a moving cavity bus. Since the positions of the trapped
ions are precisely located, the strengths and durations of the ion-cavity
interactions can be exactly controlled. As a consequence, by properly setting
the relevant parameters typical multi-ion entangled states, e.g., state for
10 ions, could be deterministically generated. The feasibility of the proposal
is also discussed.Comment: 8 pages, 2 figures, 1 tabl
Journal Staff
Discoba (Excavata) is an ancient group of eukaryotes with great morphological and ecological diversity. Unlike the other major divisions of Discoba (Jakobida and Euglenozoa), little is known about the mitochondrial DNAs(mtDNAs) of Heterolobosea. We have assembled a complete mtDNA genome from the aggregating heterolobosean amoeba, Acrasis kona, which consists of a single circular highly AT-rich (83.3%) molecule of 51.5 kb. Unexpectedly, A. kona mtDNA is missing roughly 40% of the protein-coding genes and nearly half of the transfer RNAs found in the only other sequenced heterolobosean mtDNAs, those of Naegleria spp. Instead, over a quarter of A. kona mtDNA consists of novel open reading frames. Eleven of the 16 protein-coding genes missing from A. kona mtDNA were identified in its nuclear DNA and polyA RNA, and phylogenetic analyses indicate that at least 10 of these 11 putative nuclear-encoded mitochondrial (NcMt) proteins arose by direct transfer from the mitochondrion. Acrasis kona mtDNA also employs C-to-U type RNA editing, and 12 homologs of DYW-type pentatricopeptide repeat (PPR) proteins implicated in plant organellar RNA editing are found in A. kona nuclear DNA. A mapping of mitochondrial gene content onto a consensus phylogeny reveals a sporadic pattern of relative stasis and rampant gene loss in Discoba. Rampant loss occurred independently in the unique common lineage leading to Heterolobosea + Tsukubamonadida and later in the unique lineage leading to Acrasis. Meanwhile, mtDNA gene content appears to be remarkably stable in the Acrasis sister lineage leading to Naegleria and in their distant relatives Jakobida
Lower Bound on Translative Covering Density of Tetrahedra
In this paper, we present the first nontrivial lower bound on the translative
covering density of tetrahedra. To this end, we show the lower bound, in any
translative covering of tetrahedra, on the density relative to a given cube.
The resulting lower bound on the translative covering density of tetrahedra is
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