47,XY,+dcl(9)(q34)wcp(9+)/46,XY伴隐睾一例

患儿男,10岁,因"双侧隐睾"就诊.患儿系足月、顺产、5岁时发现头颅大,经医院诊断为脑积水.几岁时做双侧隐睾手术.患儿身高120 cm.头颅发育不规则,颜面不对称,自小严重的智力低下,说话不清.

Sorex bedfordiae has the Smallest Diploid Chromosome Number of the XY Group in the Genus Sorex (Mammalia, Soricidae)

Karyological data on the lesser stripe-backed shrew, Sorex bedfordiae, were obtained from four specimens collected on Mt. Laojun, Lijiang District, Yunnan Province, China. Three of the four S. bedfordiae specimens had karyotypes consisting of 2n=26, NFa=4

从XY雌鱼雌核发育产生YY超雄黄颡鱼

采用激素性逆转结合雌核发育技术,从XY雌鱼产生YY超雄黄颡鱼。与性逆转和后代测交选种技术比较,本文的方法可以缩短两代的育种时间,并提高超雄鱼的产出。通过测交证明,与正常的XY雄鱼一样,YY超雄黄颡鱼是能成活和有生育力的,其后代雄鱼占75.9%—100%,平均90.30%。从29尾雌鱼产生的雌核发育的后代294尾,只有11尾雄鱼,绝大多数是雌鱼;而在12尾YY超雄鱼测交的后代出现0—24.1%雌鱼。从上述结果可以推测,黄颡鱼的性决定体制是雌性配子同型(XX♀/XY♂),但常染色体性修饰基因的影响是比较明显的

Disentanglement of two qubits coupled to an XY spin chain: Role of quantum phase transition

We study the disentanglement evolution of two spin qubits which interact with a general XY spin-chain environment. The dynamical process of the disentanglement is numerically and analytically investigated in the vicinity of a quantum phase transition (QPT) of the spin chain in both weak and strong coupling cases. We find that the disentanglement of the two spin qubits may be greatly enhanced by the quantum critical behavior of the environmental spin chain. We give a detailed analysis to facilitate the understanding of the QPT-enhanced decaying behavior of the coherence factor. Furthermore, the scaling behavior in the disentanglement dynamics is also revealed and analyzed.

Quantum critical phenomena in the XY spin chain with the Dzyaloshinski-Moriya interaction (Retracted article. See vol 80, artn 019903, 2009)

We study the effects of the Dzyaloshinski-Moriya (DM) anisotropic interaction on the ground-state properties of the Heisenberg XY spin chain by means of the fidelity susceptibility, order parameter, and entanglement entropy. Our results show that the DM interaction could influence the distribution of the regions of quantum phase transitions and cause different critical regions in the XY spin model. Meanwhile, the DM interaction has effective influence on the degree of entanglement of the system and could be used to increase the entanglement of the spin system.

Loschmidt echo and Berry phase of a quantum system coupled to an XY spin chain: Proximity to a quantum phase transition

We study the Loschmidt echo (LE) of a coupled system consisting of a central spin and its surrounding environment described by a general XY spin-chain model. The quantum dynamics of the LE is shown to be remarkably influenced by the quantum criticality of the spin chain. In particular, the decaying behavior of the LE is found to be controlled by the anisotropy parameter of the spin chain. Furthermore, we show that due to the coupling to the spin chain, the ground-state Berry phase for the central spin becomes nonanalytical and its derivative with respect to the magnetic parameter lambda in spin chain diverges along the critical line lambda=1, which suggests an alternative measurement of the quantum criticality of the spin chain.

Analytical study of the layered XY model with VCE method

Motivated by experiments on liquid-crystal films, we study the development of specific heat anomaly of finite layer system. With the VCE method, we introduce the strong surface interaction into the layered XY model and get the results of the forth-order analytical expansion. The results show that when the strong surface interaction becomes strong enough, the order trend defeats the quantum noise and the specific heat peak moves abnormally to the high temperature with the number of layers decreasing.