Showing 541 - 550 of 733 Items
Twisted D-branes of the over(su, ̂) (N)K WZW model and level-rank duality
Date: 2006-10-30
Creator: Stephen G. Naculich, Howard J. Schnitzer
Access: Open access
- We analyze the level-rank duality of ωc-twisted D-branes of over(su, ̂) (N)K (when N and K > 2). When N or K is even, the duality map involves Z2-cominimal equivalence classes of twisted D-branes. We prove the duality of the spectrum of an open string stretched between ωc-twisted D-branes, and ascertain the relation between the charges of level-rank-dual ωc-twisted D-branes. © 2006 Elsevier B.V. All rights reserved.
Erratum: The 'obligate diploid' Candida albicans forms mating-competent haploids (Nature (2013) 494 (55-59) DOI: 10.1038/nature11865)
Date: 2016-02-11
Creator: Meleah A. Hickman, Guisheng Zeng, Anja Forche, Matthew P. Hirakawa, Darren, Abbey, Benjamin D. Harrison, Yan Ming Wang, Ching Hua Su, Richard J. Bennett, Yue Wang, Judith Berman
Access: Open access
C-graph automatic groups
Date: 2014-09-01
Creator: Murray Elder, Jennifer Taback
Access: Open access
- We generalize the notion of a graph automatic group introduced by Kharlampovich, Khoussainov and Miasnikov by replacing the regular languages in their definition with more powerful language classes. For a fixed language class C, we call the resulting groups C-graph automatic. We prove that the class of C-graph automatic groups is closed under change of generating set, direct and free product for certain classes C. We show that for quasi-realtime counter-graph automatic groups where normal forms have length that is linear in the geodesic length, there is an algorithm to compute normal forms (and therefore solve the word problem) in polynomial time. The class of quasi-realtime counter-graph automatic groups includes all Baumslag-Solitar groups, and the free group of countably infinite rank. Context-sensitive-graph automatic groups are shown to be a very large class, which encompasses, for example, groups with unsolvable conjugacy problem, the Grigorchuk group, and Thompson's groups F, T and V. © 2014 Elsevier Inc.
Assessment and Treatment of Pathological Skin Picking
Date: 2012-09-18
Creator: Jedidiah Siev, Hannah E. Reese, Kiara Timpano, Sabine Wilhelm
Access: Open access
- Pathological skin picking (PSP) refers to chronic skin picking or scratching that causes tissue damage and distress. It is a heterogeneous category of behaviors and may be manifest in the context of various psychological disorders. This chapter presents an overview of the empirical literature on the assessment and treatment of PSP, including (1) a cognitive-behavioral model as heuristic for conceptualizing treatment, (2) assessment tools, (3) a review of the pharmacological and psychosocial treatment outcome literatures, (4) cognitive-behavioral treatment techniques, and (5) future directions. The chapter is intended to introduce the clinician to the assessment and psychological tools used to treat PSP, as well as to provide impetus to advance research in this understudied domain.
Applications of subleading-color amplitudes in N = 4 SYM theory
Date: 2011-12-01
Creator: Stephen G. Naculich, Horatiu Nastase, Howard J. Schnitzer
Access: Open access
- A number of features and applications of subleading-color amplitudes of N = 4 SYM theory are reviewed. Particular attention is given to the IR divergences of the subleading-color amplitudes, the relationships of N = 4 SYM theory to N = 8 supergravity, and to geometric interpretations of one-loop subleading-color and N k MHV amplitudes of N = 4 SYM theory. Copyright © 2011 Stephen G. Naculich et al.
Thompson's group F is 1-counter graph automatic
Date: 2016-05-01
Creator: Murray Elder, Jennifer Taback
Access: Open access
- It is not known whether Thompson's group F is automatic. With the recent extensions of the notion of an automatic group to graph automatic by Kharlampovich, Khoussainov and Miasnikov and then to C-graph automatic by the authors, a compelling question is whether F is graph automatic or C-graph automatic for an appropriate language class C. The extended definitions allow the use of a symbol alphabet for the normal form language, replacing the dependence on generating set. In this paper we construct a 1-counter graph automatic structure for F based on the standard infinite normal form for group elements.
Two-loop graviton scattering relation and IR behavior in N = 8 supergravity
Date: 2008-12-11
Creator: Stephen G. Naculich, Horatiu Nastase, Howard J. Schnitzer
Access: Open access
- We derive an ABDK-like relation between the one- and two-loop four-graviton amplitudes in N = 8 supergravity. Specifically we show that the infrared-divergent part of the two-loop amplitude is one-half the square of the one-loop amplitude, suggesting an exponential structure for IR divergences. The difference between the two-loop amplitude and one-half the square of the full one-loop amplitude is therefore finite, and expressible in a relatively simple form. We give arguments for generalizations to higher loops and n-point functions, suggesting that the exponential of the full one-loop amplitude may be corrected, to low orders, by only simple finite terms. © 2008 Elsevier B.V. All rights reserved.
Ploidy variation in fungi: Polyploidy, aneuploidy, and genome evolution
Date: 2017-07-01
Creator: Robert T. Todd, Anja Forche, Anna Selmecki
Access: Open access
- The ability of an organism to replicate and segregate its genome with high fidelity is vital to its survival and for the production of future generations. Errors in either of these steps (replication or segregation) can lead to a change in ploidy or chromosome number. While these drastic genome changes can be detrimental to the organism, resulting in decreased fitness, they can also provide increased fitness during periods of stress. A change in ploidy or chromosome number can fundamentally change how a cell senses and responds to its environment. Here, we discuss current ideas in fungal biology that illuminate how eukaryotic genome size variation can impact the organism at a cellular and evolutionary level. One of the most fascinating observations from the past 2 decades of research is that some fungi have evolved the ability to tolerate large genome size changes and generate vast genomic heterogeneity without undergoing canonical meiosis.
Separation of internal and interaction dynamics for NLS-described wave packets with different carrier waves
Date: 2008-11-01
Creator: Martina Chirilus-Bruckner, Christopher Chong, Guido Schneider, Hannes Uecker
Access: Open access
- We give a detailed analysis of the interaction of two NLS-described wave packets with different carrier waves for a nonlinear wave equation. By separating the internal dynamics of each wave packet from the dynamics caused by the interaction we prove that there is almost no interaction of such wave packets. We also prove the validity of a formula for the envelope shift caused by the interaction of the wave packets. © 2008 Elsevier Inc. All rights reserved.
Seasonal acclimatization of antioxidants and photosynthesis in Chondrus crispus and Mastocarpus stellatus, two co-occurring red algae with differing stress tolerances
Date: 2004-01-01
Creator: Nissa L. Lohrmann, Barry A. Logan, Amy S. Johnson
Access: Open access
- Mastocarpus stellatus and Chondrus crispus are red macroalgae that co-dominate the lower rocky intertidal zones of the northern Atlantic coast. M. stellatus is more tolerant than C. crispus of environmental stresses, particularly those experienced during winter. This difference in tolerance has been attributed, in part, to greater contents or activities of certain antioxidants in M. stellatus. We compared the photosynthetic capacities and activities of three antioxidant enzymes - superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR) - as well as the contents of ascorbate from fronds of M. stellatus and C. crispus collected over a year. Photosynthetic capacity increased in winter, but did not differ between species in any season. The activities of the three antioxidant enzymes and the contents of ascorbate were significantly greater in tissues collected during months with mean air and water temperatures below 7.5°C ("cold" months; December, February, March, April) than in months with mean air temperatures above 11°C ("warm" months; June, July, August, October). Overall, C. crispus had significantly greater SOD and APX activities, while M. stellatus had higher ascorbate contents. Species-specific differences in GR activity depended upon mean monthly temperatures at the time of tissue collection; C. crispus had higher activities during cold months, whereas M. stellatus had higher activities during warm months. Taken together, these data indicate that increased ROS scavenging capacity is a part of winter acclimatization; however, only trends in ascorbate content support the hypothesis that greater levels of antioxidants underlie the relatively greater winter tolerance of M. stellatus in comparison to C. crispus.