2,972 research outputs found
The deformed M2-brane
The superembedding formalism is used to study correction terms to the
dynamics of the M2 brane in a flat background. This is done by deforming the
standard embedding constraint. It is shown rigorously that the first such
correction occurs at dimension four. Cohomological techniques are used to
determine this correction explicitly. The action is derived to quadratic order
in fermions, and the modified \k-symmetry transformations are given.Comment: 38 pages, 3 figure
Study of thermal insulation for airborne liquid hydrogen fuel tanks
A concept for a fail-safe thermal protection system was developed. From screening tests, approximately 30 foams, adhesives, and reinforcing fibers using 0.3-meter square liquid nitrogen cold plate, CPR 452 and Stafoam AA1602, both reinforced with 10 percent by weight of 1/16 inch milled OCF Style 701 Fiberglas, were selected for further tests. Cyclic tests with these materials in 2-inch thicknesses bonded on a 0.6-meter square cold plate with Crest 7410 adhesive systems, were successful. Zero permeability gas barriers were identified and found to be compatible with the insulating concept
Optimal error bounds in the absence of constraint qualifications with applications to the -cones and beyond
We prove tight H\"olderian error bounds for all -cones. Surprisingly, the
exponents differ in several ways from those that have been previously
conjectured; moreover, they illuminate -cones as a curious example of a
class of objects that possess properties in 3 dimensions that they do not in 4
or more. Using our error bounds, we analyse least squares problems with
-norm regularization, where our results enable us to compute the
corresponding KL exponents for previously inaccessible values of . Another
application is a (relatively) simple proof that most -cones are neither
self-dual nor homogeneous. Our error bounds are obtained under the framework of
facial residual functions, and we expand it by establishing for general cones
an optimality criterion under which the resulting error bound must be tight.Comment: 36 pages, comments welcome. Some small fixes and three new figures
were added in order to better explain the result
On Superspace Chern-Simons-like Terms
We search for superspace Chern-Simons-like higher-derivative terms in the low
energy effective actions of supersymmetric theories in four dimensions.
Superspace Chern-Simons-like terms are those gauge-invariant terms which cannot
be written solely in terms of field strength superfields and covariant
derivatives, but in which a gauge potential superfield appears explicitly. We
find one class of such four-derivative terms with N=2 supersymmetry which,
though locally on the Coulomb branch can be written solely in terms of field
strengths, globally cannot be. These terms are classified by certain Dolbeault
cohomology classes on the moduli space. We include a discussion of other
examples of terms in the effective action involving global obstructions on the
Coulomb branch.Comment: 23 pages; a reference and an author email correcte
Preventing type 2 diabetes mellitus in Qatar by reducing obesity, smoking, and physical inactivity: mathematical modeling analyses.
BACKGROUND: The aim of this study was to estimate the impact of reducing the prevalence of obesity, smoking, and physical inactivity, and introducing physical activity as an explicit intervention, on the burden of type 2 diabetes mellitus (T2DM), using Qatar as an example. METHODS: A population-level mathematical model was adapted and expanded. The model was stratified by sex, age group, risk factor status, T2DM status, and intervention status, and parameterized by nationally representative data. Modeled interventions were introduced in 2016, reached targeted level by 2031, and then maintained up to 2050. Diverse intervention scenarios were assessed and compared with a counter-factual no intervention baseline scenario. RESULTS: T2DM prevalence increased from 16.7% in 2016 to 24.0% in 2050 in the baseline scenario. By 2050, through halting the rise or reducing obesity prevalence by 10-50%, T2DM prevalence was reduced by 7.8-33.7%, incidence by 8.4-38.9%, and related deaths by 2.1-13.2%. For smoking, through halting the rise or reducing smoking prevalence by 10-50%, T2DM prevalence was reduced by 0.5-2.8%, incidence by 0.5-3.2%, and related deaths by 0.1-0.7%. For physical inactivity, through halting the rise or reducing physical inactivity prevalence by 10-50%, T2DM prevalence was reduced by 0.5-6.9%, incidence by 0.5-7.9%, and related deaths by 0.2-2.8%. Introduction of physical activity with varying intensity at 25% coverage reduced T2DM prevalence by 3.3-9.2%, incidence by 4.2-11.5%, and related deaths by 1.9-5.2%. CONCLUSIONS: Major reductions in T2DM incidence could be accomplished by reducing obesity, while modest reductions could be accomplished by reducing smoking and physical inactivity, or by introducing physical activity as an intervention
Generalized power cones: optimal error bounds and automorphisms
Error bounds are a requisite for trusting or distrusting solutions in an
informed way. Until recently, provable error bounds in the absence of
constraint qualifications were unattainable for many classes of cones that do
not admit projections with known succinct expressions. We build such error
bounds for the generalized power cones, using the recently developed framework
of one-step facial residual functions. We also show that our error bounds are
tight in the sense of that framework. Besides their utility for understanding
solution reliability, the error bounds we discover have additional applications
to the algebraic structure of the underlying cone, which we describe. In
particular we use the error bounds to compute the dimension of the automorphism
group for the generalized power cones, and to identify a set of generalized
power cones that are self-dual, irreducible, nonhomogeneous, and perfectComment: 24 pages, title change, some minor fixes throughout the paper and
removed the appendix. Comments welcom
Inheritance of Carbohydrates and Fat in Corn
Chemical analyses of cross-bred ears, involving the yellow dent (Iodent) and white Evergreen sweet corn varieties, have yielded some interesting results with respect to the detailed mode of inheritance of sugars, dextrins, starches, and fat. High sugar and dextrin (also low starch) are distinctly recessive in inheritance, although there is a small cumulative effect of the genetic factors represented in the endosperm development with its 3x condition. No such cumulative effect is present with respect to fat, the hybrids (made reciprocally) having identical values, intermediate in percentage, but with a slight tendency towards a dominance of low fat. Carbohydrate and fat values are interrelated genetically, but very likely this indicates a morphological relation within the kernel
Dead Time, Pileup, and Accurate Gamma-Ray Spectrometry
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58611/1/R&R.pd
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