56,602 research outputs found
The Advantages of Odd Exclusions
Every novel constitutes an interestingly complex set of linguistic experiments demonstrating some of the possibilities of its language to and by the exclusion of all the rest. Extreme cases may demonstrate these possibilities more clearly, and at least in English, no novel seems more arbitrarily extreme than Gadsby, which Ernest Vincent Wright apparently wrote in 1936-1937, with the E typebar of his typewriter tied down with string because, he said in his introduction, someone had told him he could not write coherent grammatical English without using its most common letter
The Character of Transport Caused by ExB Drift Turbulence
The basic character of diffusive transport in a magnetised plasma depends on
what kind of transport is modelled. ExB turbulence under drift ordering has
special characteristics: it is nearly incompressible, and it cannot lead to
magnetic flux diffusion if it is electrostatic. The ExB velocity is also
related to the Poynting energy flux. Under quasineutral dynamics, electric
fields are not caused by transport of electric charge but by the requirement
that the total current is divergence free. Consequences for well constructed
computational transport models are discussed in the context of a general mean
field analysis, which also yields several anomalous transfer mechanisms not
normally considered by current models.Comment: 31 pages including 2 figures, submitted to Physics of Plasma
Phases and phase transitions in a U(1) × U(1) system with θ = 2π/3 mutual statistics
We study a U(1) × U(1) system with short-range interactions and mutual θ = 2π/3 statistics in (2+1)
dimensions. We are able to reformulate the model to eliminate the sign problem and perform a Monte Carlo
study. We find a phase diagram containing a phase with only small loops and two phases with one species of
proliferated loop. We also find a phase where both species of loop condense, but without any gapless modes.
Lastly, when the energy cost of loops becomes small, we find a phase that is a condensate of bound states, each
made up of three particles of one species and a vortex of the other. We define several exact reformulations of the
model that allow us to precisely describe each phase in terms of gapped excitations. We propose field-theoretic
descriptions of the phases and phase transitions, which are particularly interesting on the “self-dual” line where
both species have identical interactions. We also define irreducible responses useful for describing the phases
Monte Carlo Study of a U(1)xU(1) system with \pi-statistical Interaction
We study a system with two species of loops with mutual
-statistics in (2+1) dimensions. We are able to reformulate the model in a
way that can be studied by Monte Carlo and we determine the phase diagram. In
addition to a phase with no loops, we find two phases with only one species of
loop proliferated. The model has a self-dual line, a segment of which separates
these two phases. Everywhere on the segment, we find the transition to be
first-order, signifying that the two loop systems behave as immiscible fluids
when they are both trying to condense. Moving further along the self-dual line,
we find a phase where both loops proliferate, but they are only of even
strength, and therefore avoid the statistical interactions. We study another
model which does not have this phase, and also find first-order behavior on the
self-dual segment.Comment: 4 pages, 5 figure
A Symbiotic View Of Life: We Have Never Been Individuals
The notion of the biological individual is crucial to studies of genetics, immunology, evolution, development, anatomy, and physiology. Each of these biological subdisciplines has a specific conception of individuality, which has historically provided conceptual contexts for integrating newly acquired data. During the past decade, nucleic acid analysis, especially genomic sequencing and high-throughput RNA techniques, has challenged each of these disciplinary definitions by finding significant interactions of animals and plants with symbiotic microorganisms that disrupt the boundaries that heretofore had characterized the biological individual. Animals cannot be considered individuals by anatomical or physiological criteria because a diversity of symbionts are both present and functional in completing metabolic pathways and serving other physiological functions. Similarly, these new studies have shown that animal development is incomplete without symbionts. Symbionts also constitute a second mode of genetic inheritance, providing selectable genetic variation for natural selection. The immune system also develops, in part, in dialogue with symbionts and thereby functions as a mechanism for integrating microbes into the animal-cell community. Recognizing the holobiont -the multicellular eukaryote plus its colonies of persistent symbionts-as a critically important unit of anatomy, development, physiology, immunology, and evolution opens up new investigative avenues and conceptually challenges the ways in which the biological subdisciplines have heretofore characterized living entities
- …