999 research outputs found
Line Defects, Tropicalization, and Multi-Centered Quiver Quantum Mechanics
We study BPS line defects in N=2 supersymmetric four-dimensional field
theories. We focus on theories of "quiver type," those for which the BPS
particle spectrum can be computed using quiver quantum mechanics. For a wide
class of models, the renormalization group flow between defects defined in the
ultraviolet and in the infrared is bijective. Using this fact, we propose a way
to compute the BPS Hilbert space of a defect defined in the ultraviolet, using
only infrared data. In some cases our proposal reduces to studying
representations of a "framed" quiver, with one extra node representing the
defect. In general, though, it is different. As applications, we derive a
formula for the discontinuities in the defect renormalization group map under
variations of moduli, and show that the operator product algebra of line
defects contains distinguished subalgebras with universal multiplication rules.
We illustrate our results in several explicit examples.Comment: 76 pages, 10 figures; v2: minor revisions, correction to Coulomb
branch calculation for defects in SU(2) SY
Investigation of Low-Temperature Effects on DNA Photocleavage Using a Novel Thioether Substituted Cyanine Dye
The implications of temperature effects on photochemical processes when it comes to near-infrared DNA photosensitizing agents are discussed in addition to the unique spectroscopic features of a sulfur meso-substituted heptamethine cyanine dye relative to oxygen and nitrogen analogues. Specifically, reactive oxygen scavenger experiments, preliminary kinetic data, and absorption spectra are considered in this continued investigation. Additionally, binding and stability studies indicate that the general structure of the cyanine dye can be further optimized to potentially improve DNA photocleavage yields at physiological temperatures while employing the exceptional properties of sulfur-incorporated polymethine dyes
The Perception and Cognition of Time in Balinese Music
This article describes experiments designed to determine the perception and cognition of time-in-music among Balinese gamelan musicians. Three topics are discussed. First, the proposed connections between cultural/religious concepts of time and the construction of (time in) gamelan music are explored. Here a novel and experimental use of the Implicit Association Test is incorporated to explore potential implicit (unconscious) connections between concepts of time-in-music and time-in-general. Only weak associations are found. Second, the author explores music’s influence in subjects’ ability to gauge objective durations. Other than a tendency for Balinese subjects to consistently underestimate actual timings, and the potential for tempo changes to influence response patterns in specific ways, few strong patterns are found. Third, previously proposed models for the performance of tempo changes (here, rallentandos) are explored in the context of gamelan music. Results from perceptual tasks and an analysis of performance suggests that previous idealized models are too simplistic to describe the Balinese case
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Strategic drift in military-to-military relationships and its effect on U.S. foreign policy
textThe United States has different methods by which it leverages its influence on allies throughout the world. Military-to-military partnerships constitute one of the most effective methods, particularly when the U.S. seeks to influence developing nations or ones that are in the midst of difficult political transitions. However, recent events demonstrate that these mil-to-mil partnerships are not as effective as they should be. This paper seeks to examine one aspect of the mil-to-mil partnership, namely sales of U.S. military equipment through the Foreign Military Sales (FMS) program and the complementary Foreign Military Financing (FMF) program, through which the United States provides the funding to finance said purchases. This paper argues that the United States has continually "moved the goalposts" in justifying its FMF outlays and FMS authorizations, to the effect that the United States is dependent on the continuation of the very programs that are designed to be little more than tools that allow the foreign policy establishment to influence its partners. This "strategic drift" in the mil-to-mil relationship as evidenced through the FMS/FMF program is examined in detail in Egypt, with a focus on events that have transpired since longtime President Hosni Mubarak's ouster in February 2011. The paper seeks to demonstrate that when FMS/FMF is tied to external agreements upon which the United States is dependent - whether diplomatic or military - it creates an incentive for planners in both the Departments of Defense and State to resort to self-justifying analyses bearing little resemblance to the original purpose of the FMS/FMF agreements or to the United States' legitimate national interest in a given region. Large scale reforms of the architecture of security assistance, both political and administrative, are unlikely to occur for a variety of reasons that are touched upon in the paper. By looking at the historical, political, and military aspects of security assistance more broadly, the paper argues that if the United States wants to achieve clarity on whether its security assistance programs truly serve the United States' best interests, it will need to do so at lower levels in the relative implementing agencies.Middle Eastern Studie
A sharp bound on fixed points of surface symplectomorphisms in each mapping class
Given a closed, oriented surface, possibly with boundary, and a mapping
class, we obtain sharp lower bounds on the number of fixed points of a surface
symplectomorphism (i.e. area-preserving map) in the given mapping class, both
with and without nondegeneracy assumptions on the fixed points. This
generalizes the Poincar\'e-Birkhoff fixed point theorem to arbitrary surfaces
and mapping classes. These bounds often exceed those for non-area-preserving
maps. We obtain these bounds from Floer homology computations with certain
twisted coefficients plus a method for obtaining fixed point bounds on entire
symplectic mapping classes on monotone symplectic manifolds from such
computations. For the case of possibly degenerate fixed points, we use
quantum-cup-length-type arguments for certain cohomology operations we define
on summands of the Floer homology.Comment: 25 pages, 14 figure
When will my turn come? : the civil service purges and the construction of a gay security risk in the Cold War United States, 1945-1955
In the 1940s and 1950s, the United States was gripped by an intense anxiety about its national security. While primarily triggered by the external threat of the Soviet Union, this anxiety was especially centred on internal threats, real and imagined. Most previous studies have focused on the so-called “Red Scare,” the hunt for Communists and other political undesirables. This was accompanied by a parallel “Lavender Scare,” an assault on homosexuality in American culture, especially public service. Homosexuality had been grounds for dismissal from the Civil Service since the 19th Century, but Cold War anxiety about gays in government became so great that some in the press began referring to it as a “Panic on the Potomac.” Fear of sexual subversion became so integrated into the larger national security obsession that, by 1955, fully 1 in every 5 American workers was subject to a combination of loyalty and security restrictions, related to both political and “moral” categories of unsuitability. Yet this episode has remained a largely forgotten footnote in American Cold War experience.
The homophobia that characterized the early Cold War was new, more intense, and unique to that moment in history. Full-scale investigations and purges of suspected gays from the Civil Service began in 1950, but possessed deeper roots in the politics and culture of the era. They were stimulated by a combination of Cold War anxiety, post-war conservatism, and a changing conception of the nature of homosexuality. The effects of the purges would include not only widespread dismissals and intensified repression of gays and lesbians, but also the emergence of gay activism and the concept of a distinct gay minority. The evolving nature of gay identity, especially self-identity, is ultimately central to the thesis topic. This thesis is one of a small, but growing number of works that attempt to comprehensively examine the origins, characteristics, and impacts of the Lavender Scare. It draws on a wide range of sources, including the most recent specialized studies and the best available primary sources, including archival materials, first-hand recollections of events, and newly declassified government documents
Temperature, light and nitrate sensing coordinate Arabidopsis seed dormancy cycling resulting in winter and summer annual phenotypes
Seeds use environmental cues to sense the seasons and their surroundings to initiate the plants life cycle. Dormancy cycling underlying this process is extensively described, but the molecular mechanism is largely unknown. To address this we selected a range of representative genes from published array experiments in the laboratory and investigated their expression patterns in seeds of Arabidopsis ecotypes, having contrasting life cycles, over an annual dormancy cycle in the field. We show how mechanisms identified in the laboratory are coordinated in response to the soil environment to determine dormancy cycles that result in winter and summer annual phenotypes. Our results are consistent with a seed specific response to seasonal temperature patterns (temporal sensing) involving the gene DELAY OF GERMINATION1 (DOG1) that indicates the correct season; and concurrent temporally driven co-opted mechanisms that sense spatial signals i.e. nitrate via CBL-INTERACTING PROTEIN KINASE 23 (CIPK23) phosphorylation of the NITRATE TRANSPORTER 1 (NRT1.1) and light via PHYTOCHROME A (PHYA). In both ecotypes studied, when all three genes have low expression there is enhanced GIBBERELLIN 3 BETA-HYDROXYLASE 1 (GA3ox1) expression, exhumed seeds have the potential to germinate in the laboratory, and the initiation of seedling emergence occurs following soil disturbance (exposure to light) in the field. Unlike DOG1, expression of MOTHER of FLOWERING TIME (MFT) has an opposite thermal response in seeds of the two ecotypes indicating a role in determining their different dormancy cycling phenotypes
Validation of Vehicle Panel/Equipment Response from Diffuse Acoustic Field Excitation Using Spatially Correlated Transfer Function Approach
An approach for predicting the vibration, strain, and force responses of a flight-like vehicle panel assembly to acoustic pressures is presented. Important validation for the approach is provided by comparison to ground test measurements in a reverberant chamber. The test article and the corresponding analytical model were assembled in several configurations to demonstrate the suitability of the approach for response predictions when the vehicle panel is integrated with equipment. Critical choices in the analysis necessary for convergence of the predicted and measured responses are illustrated through sensitivity studies. The methodology includes representation of spatial correlation of the pressure field over the panel surface. Therefore, it is possible to demonstrate the effects of hydrodynamic coincidence in the response. The sensitivity to pressure patch density clearly illustrates the onset of coincidence effects on the panel response predictions
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