Genetic diversity and selective breeding of red common carps in China

China has a very rich genetic diversity in common carp (Cyprinus carpio) and the red common carp plays an important role in Chinese aquaculture and genetic studies. Selective breeding, particularly crossbreeding has been applied successfully to red common carps in China, and the products of these efforts have been in commercial use since the 1970s. However, knowledge of the quantitative and molecular genetics of these carps is limited. Studies were therefore undertaken to: (1) understand the genetic diversity and genetic relationship of red common carps in China; (2) understand the inheritance of color phenotype of Oujiang color carp; (3) select stable Oujiang color carp with fast growth rate and ornamental Oujiang color carp comparable with the Koi common carp from Japan; (4) study the culture performance and culture systems suitable for the Oujiang color carp in cages and paddies; (5) extend better quality fish and appropriate culture systems for small scale fish farmers in poor areas

Which finitely generated Abelian groups admit isomorphic Cayley graphs?

We show that Cayley graphs of finitely generated Abelian groups are rather rigid. As a consequence we obtain that two finitely generated Abelian groups admit isomorphic Cayley graphs if and only if they have the same rank and their torsion parts have the same cardinality. The proof uses only elementary arguments and is formulated in a geometric language.Comment: 16 pages; v2: added reference, reformulated quasi-convexity, v3: small corrections; to appear in Geometriae Dedicat

A Necessary And Sufficient Condition of Distillability with unite fidelity from Finite Copies of a Mixed State: The Most Efficient Purification Protocol

It is well known that any entangled mixed state in $2\otimes 2$ systems can be purified via infinite copies of the mixed state. But can one distill a pure maximally entangled state from finite copies of a mixed state in any bipartite system by local operation and classical communication? This is more meaningful in practical application. We give a necessary and sufficient condition of this distillability. This condition can be expressed as: there exists distillable-subspaces. According to this condition, one can judge whether a mixed state is distillable or not easily. We also analyze some properties of distillable-subspaces, and discuss the most efficient purification protocols. Finally, we discuss the distillable enanglement of two-quibt system for the case of finite copies.Comment: a revised versio

Efficient quantum key distribution scheme with nonmaximally entangled states

We propose an efficient quantum key distribution scheme based on entanglement. The sender chooses pairs of photons in one of the two equivalent nonmaximally entangled states randomly, and sends a sequence of photons from each pair to the receiver. They choose from the various bases independently but with substantially different probabilities, thus reducing the fraction of discarded data, and a significant gain in efficiency is achieved. We then show that such a refined data analysis guarantees the security of our scheme against a biased eavesdropping strategy.Comment: 5 Pages, No Figur

Local transformation of mixed states of two qubits to Bell diagonal states

The optimal entanglement manipulation for a single copy of mixed states of two qubits is to transform it to a Bell diagonal state. In this paper we derive an explicit form of the local operation that can realize such a transformation. The result obtained is universal for arbitrary entangled two-qubit states and it discloses that the corresponding local filter is not unique for density matrices with rank $n=2$ and can be exclusively determined for that with $n=3$ and 4. As illustrations, a four-parameters family of mixed states are explored, the local filter as well as the transformation probability are given explicitly, which verify the validity of the general result.Comment: 5 pages, to be published in Phys. Rev.

A novel quantum key distribution scheme with orthogonal product states

The general conditions for the orthogonal product states of the multi-state systems to be used in quantum key distribution (QKD) are proposed, and a novel QKD scheme with orthogonal product states in the 3x3 Hilbert space is presented. We show that this protocol has many distinct features such as great capacity, high efficiency. The generalization to nxn systems is also discussed and a fancy limitation for the eavesdropper's success probability is reached.Comment: 4 Pages, 3 Figure

Entanglement, quantum phase transition and scaling in XXZ chain

Motivated by recent development in quantum entanglement, we study relations among concurrence $C$, SU$_q$(2) algebra, quantum phase transition and correlation length at the zero temperature for the XXZ chain. We find that at the SU(2) point, the ground state possess the maximum concurrence. When the anisotropic parameter $\Delta$ is deformed, however, its value decreases. Its dependence on $\Delta$ scales as $C=C_0-C_1(\Delta-1)^2$ in the XY metallic phase and near the critical point (i.e. $1<\Delta<1.3$) of the Ising-like insulating phase. We also study the dependence of $C$ on the correlation length $\xi$, and show that it satisfies $C=C_0-1/2\xi$ near the critical point. For different size of the system, we show that there exists a universal scaling function of $C$ with respect to the correlation length $\xi$.Comment: 4 pages, 3 figures. to appear in Phys. Rev.

How Big is an Acupoint?

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Electrodeposition of Ni-Si Schottky barriers

Electrodeposition is being used to fabricate magnetic microstructures directly on patterned n-type Si wafers of various substrate resistivities. The Ni-Si Schottky barrier is characterized and found to be of high quality for relatively low Si resistivities (1-2 Omega(.)cm), with extremely low reverse leakage. It is shown that a direct correlation exists among the electrodeposition potential, the roughness, and the coercivity of the films. A conductive seed layer or a back contact is not compulsory for electrodeposition on Si with resistivities up to 15 Omega(.)cm. This shows that electrodeposition of magnetic materials on Si might be a viable fabrication technique for magnetoresistance and spintronics applications