320 research outputs found

    Alien Registration- Wilson, Lew A. (Augusta, Kennebec County)

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    https://digitalmaine.com/alien_docs/18683/thumbnail.jp

    Consequences of local gauge symmetry in empirical tight-binding theory

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    A method for incorporating electromagnetic fields into empirical tight-binding theory is derived from the principle of local gauge symmetry. Gauge invariance is shown to be incompatible with empirical tight-binding theory unless a representation exists in which the coordinate operator is diagonal. The present approach takes this basis as fundamental and uses group theory to construct symmetrized linear combinations of discrete coordinate eigenkets. This produces orthogonal atomic-like "orbitals" that may be used as a tight-binding basis. The coordinate matrix in the latter basis includes intra-atomic matrix elements between different orbitals on the same atom. Lattice gauge theory is then used to define discrete electromagnetic fields and their interaction with electrons. Local gauge symmetry is shown to impose strong restrictions limiting the range of the Hamiltonian in the coordinate basis. The theory is applied to the semiconductors Ge and Si, for which it is shown that a basis of 15 orbitals per atom provides a satisfactory description of the valence bands and the lowest conduction bands. Calculations of the dielectric function demonstrate that this model yields an accurate joint density of states, but underestimates the oscillator strength by about 20% in comparison to a nonlocal empirical pseudopotential calculation.Comment: 23 pages, 7 figures, RevTeX4; submitted to Phys. Rev.

    A Study of Time-Dependent CP Asymmetry in B 0 → J/ψ π 0 Decays The BABAR Collaboration

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    We present our first study of the time-dependent CP-violating asymmetry in B 0 → J/ψ π 0 decays using e + e − annihilation data collected with the BABAR detector at the Υ (4S) resonance during the years 1999–2002 at the PEP-II asymmetric-energy B Factory at SLAC. With about 88 million BB pairs, our preliminary results for the coefficients of the cosine and sine terms of the CP asymmetr

    Rad17 Plays a Central Role in Establishment of the Interaction between TopBP1 and the Rad9-Hus1-Rad1 Complex at Stalled Replication Forks

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    Rad17 is critical for the ATR-dependent activation of Chk1 during checkpoint responses. It is known that Rad17 loads the Rad9-Hus1-Rad1 (9-1-1) complex onto DNA. We show that Rad17 also mediates the interaction of 9-1-1 with the ATR-activating protein TopBP1 in Xenopus egg extracts. Studies with Rad17 mutants indicate that binding of ATP to Rad17 is essential for the association of 9-1-1 and TopBP1. Furthermore, hydrolysis of ATP by Rad17 is necessary for the loading of 9-1-1 onto DNA and the elevated, checkpoint-dependent accumulation of TopBP1 on chromatin. Significantly, a mutant 9-1-1 complex that cannot bind TopBP1 has a normal capacity to promote elevated accumulation of TopBP1 on chromatin. Taken together, we propose the following mechanism. First, Rad17 loads 9-1-1 onto DNA. Second, TopBP1 accumulates on chromatin in a manner that depends on both Rad17 and 9-1-1. Finally, 9-1-1 and TopBP1 dock in a Rad17-dependent manner before activation of Chk1

    An exploratory analysis of planning characteristics in Australian visitor attractions

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    This paper provides an exploratory analysis of the planning practices of 408 Australian attraction operators. The results indicate that attraction managers can be divided into four categories: those that do not engage in any formal planning, those that adopt a short-term planning approach, those that develop long-term plans, and those that use both short-term and long-term planning approaches. An evaluation of the sophistication of attraction planning showed a bipolar distribution. Attraction managers favored a planning horizon of three or five years, and were inclined to involve their employees in the planning process. Managers relied strongly on their own research and tourism industry intelligence when formulating business plans. The content of plans tended to focus on operational activities, financial planning and marketing. The study provides a benchmark for the comparison of attraction planning efforts in various contexts. © 2006 Asia Pacific Tourism Association

    Fructose-1,6-bisphosphate and aldolase mediate glucose sensing by AMPK

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    葡萄糖是生物中最基本、最主要的营养物质,它不仅是机体能量的主要来源,也是生物质合成的主要原料。因此,葡萄糖的水平对于生物体是极其重要的。然而,在生活中,体内葡萄糖水平的波动是十分常见的,这是因为我们不可能每时每刻都在摄入葡萄糖:睡一大觉、剧烈运动几个小时或者太忙了没时间吃饭,都会引起葡萄糖水平的显著下降。这时,机体能够触发一套有效的过程应对这类“不利情况”,其中最为关键的就是激活“代谢的核心调节”——AMPK。在葡萄糖水平下降时,被激活的AMPK能够迅速启动脂肪、蛋白质的分解代谢,关闭它们的合成代谢,从而起到维持机体的能量和物质代谢的平衡,弥补机体因葡萄糖不足引起的胁迫压力。那么,机体如何感受葡萄糖水平下降,并“传递”给AMPK使其激活呢?林圣彩教授课题组的这项研究正是发现了生理状态下机体感受葡萄糖水平的机制。通过研究他们发现,无论在不含葡萄糖的细胞培养条件下,还是在饥饿的低血糖的动物体内,都不能观测到AMP水平的上升,这充分说明了机体有一套尚不为人知的、独立于AMP的感应葡萄糖水平的机制。在进一步的研究中他们揭示了这一完整过程:葡萄糖水平下降将引起的葡萄糖代谢中间物——果糖1,6-二磷酸(fructose-1,6-bisphosphate)水平的下降,该过程进一步地被糖酵解通路上的代谢酶——醛缩酶(aldolase)感应,因为醛缩酶正是将含有6个碳原子的果糖1,6-二磷酸裂解成三碳糖的酶,一旦醛缩酶“吃不到”由葡萄糖衍生的果糖1,6-二磷酸,它便“翻脸”,传递给也正是林圣彩教授课题组先前发现的溶酶体途径进而激活AMPK。该过程完全不涉及AMP水平,即能量水平的变化,是一条全新的、完全建立在实际的生理情况上的通路。林圣彩教授进一步地把葡萄糖水平总结为一种“状态信号”,以区别于传统的“能量信号”。据悉,该葡萄糖感知通路的发现对开发用于治疗肥胖症,乃至延长寿命的药物具有深远的意义。【Abstract】The major energy source for most cells is glucose, from which ATP is generated via glycolysis and/or oxidative metabolism. Glucose deprivation activates AMP-activated protein kinase (AMPK)1, but it is unclear whether this activation occurs solely via changes in AMP or ADP, the classical activators of AMPK2, 3, 4, 5. Here, we describe an AMP/ADP-independent mechanism that triggers AMPK activation by sensing the absence of fructose-1,6-bisphosphate (FBP), with AMPK being progressively activated as extracellular glucose and intracellular FBP decrease. When unoccupied by FBP, aldolases promote the formation of a lysosomal complex containing at least v-ATPase, ragulator, axin, liver kinase B1 (LKB1) and AMPK, which has previously been shown to be required for AMPK activation6, 7. Knockdown of aldolases activates AMPK even in cells with abundant glucose, whereas the catalysis-defective D34S aldolase mutant, which still binds FBP, blocks AMPK activation. Cell-free reconstitution assays show that addition of FBP disrupts the association of axin and LKB1 with v-ATPase and ragulator. Importantly, in some cell types AMP/ATP and ADP/ATP ratios remain unchanged during acute glucose starvation, and intact AMP-binding sites on AMPK are not required for AMPK activation. These results establish that aldolase, as well as being a glycolytic enzyme, is a sensor of glucose availability that regulates AMPK.D.G.H. was supported by an Investigator Award from the Wellcome Trust (097726) and a Programme Grant from Cancer Research UK (C37030/A15101). S.-C.L. was supported by grants from the National Key Research and Development Project of China (2016YFA0502001) and the National Natural Science Foundation of China (#31430094, #31690101, #31571214, #31601152 and #J1310027)

    Variability of Brown Dwarfs

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    Brown dwarfs constitute a missing link between low-mass stars and giant planets. Their atmospheres display chemical species typical of planets, and one could wonder whether they also have weather-like patterns. While brown dwarf surface features cannot be directly resolved, the photometric and spectroscopic modulations induced by these features, as they rotate in and out of view, provide a wealth of information on the evolution of their atmosphere. A review of brown dwarfs variability through the L, T and Y spectral types sequence is presented, as well as the constraints that they set on the nature of weather-like patterns on their surface.Comment: Accepted chapter in the "Handbook of Exoplanets"; Springe

    Adapting dialectical behaviour therapy in forensic learning disability services:A grounded theory informed study of "what works"

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    Background: Emerging evidence indicates effectiveness of dialectical behaviour therapy (DBT) for people with intellectual disabilities (PWID) in forensic settings; however, little is known about “what works” facilitating engagement and change. Methods: Eleven interviews were conducted with nine service users across two secure inpatient services. Grounded theory was used to develop a model of perceived engagement and change. Results: The model provides insights into how change occurs during DBT delivered in forensic settings. DBT constitutes a challenging journey, yet provides the motivation and means to address individual's intra-/interpersonal aggression and progress towards release. Participants experienced engaging with DBT as difficult and coercive, moving from compliance and avoidance to acceptance and change. Key factors included participants’ motivation, beliefs about safety and ability to change, and interactions with staff. Conclusion: Recommendations are made for increasing intrinsic motivation, reducing perceived coercion and distress, and for future research to address potential aversive elements and enhance effectiveness
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