Disentanglement of Two Qubits Coupled to an XY Spin Chain at Finite Temperature

The disentanglement evolution of bipartite spin-1/2 system coupled to a common surrounding XY chain in transverse fields at nonzero temperature is studied in this letter. The dynamical process of the entanglement is numerically and analytically investigated. We find that thermal effects can enhance disentanglement if the entangled initial state of the central spins does not in the decoherence free space. The critical phenomenon of quantum phase transitions reflected in the disentanglement can be washed out by the thermal effect eventually.

Long-term natural history of Crohn’s disease

Crohn’s disease is a chronic inflammatory granulomatous process that usually involves different sites in the intestinal tract. Genetic and environmental factors are thought to play a role in its etiology and pathogenesis. The disorder has a heterogeneous clinical expression and data from tertiary care settings have documented its female predominance, occasional familial nature, and high rate of stricture formation and penetrating disease. It may appear from early childhood to late adulthood, although over 80% are currently diagnosed before age 40 years, usually with terminal ileal and colonic involvement. Several studies have now shown differences in phenotypic clinical expression depending on the initial age at diagnosis, with pediatric-onset disease being more severe and more extensive with more involvement of the upper gastrointestinal tract compared to adult-onset disease. In addition, long- term studies from these tertiary care settings have documented that the disorder may evolve with time into a more complex disease with stricture formation and penetrating disease complications (i.e. fistula and abscess). Although prolonged remission with no evidence of inflammatory disease may occur, discrete periods of symptomatic and active granulomatous inflammatory disease may re-appear over many decades. Long-term studies on the natural history have also suggested that discrete events (or agents) may precipitate this granulomatous inflammatory process.

Intraductal papillary mucinous neoplasm in chronic calcifying pancreatitis:Egg or hen?

Intraductal papillary mucinous neoplasm(IPMN)is an increasingly reported entity.Extensive pancreatic calcification is generally thought to be a sign of chronic pancreatitis,but it may occur simultaneously with IPMN leading to diagnostic difficulties.We report a case of a patient initially diagnosed with chronic calcifying pancreatitis who was later shown to have a malignant IPMN.This case illustrates potential pitfalls in the diagnosis of IPMN in the case of extensive pancreatic calcification as well as clues that may lead the clinician to suspecting the diagnosis.The possible mechanisms of the relation between pancreatic calcification and IPMN are also reviewed.

Stability of perfect and imperfect cylindrical shells under axial compression and torsion

Stability analyses of perfect and imperfect cylindrical shells under axial compression and torsion were presented. Finite element method for the stability analysis of perfect cylindrical shells was put forward through comparing critical loads and the first buckling modes with those obtained through theoretical analysis. Two typical initial defects, non-circularity and uneven thickness distribution, were studied. Critical loads decline with the increase of non-circularity, which exist in imperfect cylindrical shells under both axial compression and torsion. Non-circularity defect has no effect on the first buckling mode when cylindrical shell is under torsion. Unfortunately, it has a completely different buckling mode when cylindrical shell is under axial compression. Critical loads decline with the increase of thickness defect amplitude, which exist in imperfect cylindrical shells under both axial compression and torsion, too. A greater wave number is conducive to the stability of cylindrical shells. The first buckling mode of imperfect cylindrical shells under torsion maintains its original shape, but it changes with wave number when the cylindrical shell is under axial compression.

临黄庭坚《诸上座帖》手记

此帖是黄山谷草书中结构最奇特,笔势最沉着而痛快,通卷前后书写节奏变化最多的一件。实临极不容易,特别是上述三方面,临写时要时时用心体会,捕捉当下感觉。笔,选用中号狼毫或七紫三羊之类偏硬毫者。初临纸宜半熟。

传统加传统的出新

熟悉王蘧常书作的人’大约都见到过“明两翁九十后作”的白文大印,作者是年轻的徐镕。现在这一浑成印品’因大书家的喜爱而留蜆于他的墓碣传递着无声而悠远的褒奖,也成了对徐君深入艺术的终身鞭策。徐镕自幼就热爱书法,初临《多宝塔碑》、《曹全碑》,并迷上篆刻,由兄长启蒙,童衍方先生引导入门。

黄庭坚“以剧喻诗”辨析

“以剧喻诗”在宋代文坛蔚为风气,特别是黄庭坚及江西诗派的新变尝试。本论以黄诗为考察对象,认为它主要借鉴了宋杂剧的“全以故事世务滑稽”即“插科打诨”而设计谐趣,和“本为鉴戒,或隐为谏诤”而寓庄于谐。重点辨析了黄庭坚“以剧喻诗”中“初时布置”的含义及其与“临了打诨”的互动关系:“初时布置”即预设诙谐情调,为“临了打诨”获得喜剧效果服务;“临了打诨”使莫名其妙的“初时布置”之用意———诙谐情调豁然明了。它与诗歌章法、句法和字法无关;也与杂剧演出收拾勾栏、安排段数、开场、正戏、登场、出场无涉。