620 research outputs found
Whose absentee votes are returned and counted: The variety and use of absentee ballots in California
Absentee voting is becoming more prevalent throughout the United States. Although there has been some research focused on who votes by absentee ballot, little research has considered another important question about absentee voting: which absentee ballots are counted and which are not? Research in the wake of the 2000 presidential election has studied the problem of uncounted ballots for precinct voters but not for absentee voters. Using data from Los Angeles County – nation's largest and most diverse voting jurisdiction – for the November 2002 general election, we test a series of hypotheses that certain types of voters have a higher likelihood that their ballots will be counted. We find that uniform service personnel, overseas civilians, voters who request non-English ballots and permanent absentee voters have a much lower likelihood of returning their ballot, and once returned, a lower likelihood that their ballots will be counted compared with the general absentee voting population. We also find that there is little partisan effect as to which voters are more likely to return their ballots or have their ballots counted. We conclude our paper with a discussion of the implications of our research for the current debates about absentee voting
Rotational symmetry and degeneracy: a cotangent-perturbed rigid rotator of unperturbed level multiplicity
We predict level degeneracy of the rotational type in diatomic molecules
described by means of a cotangent-hindered rigid rotator. The problem is shown
to be exactly solvable in terms of non-classical Romanovski polynomials. The
energies of such a system are linear combinations of t(t+1) and 1/[t(t+1)+1/4]
terms with the non-negative integer principal quantum number t=n+|/bar{m}|
being the sum of the degree n of the polynomials and the absolute value,
|/bar{m}|, of the square root of the separation constant between the polar and
azimuthal motions. The latter obeys, with respect to t, the same branching
rule, |/bar{m}|=0,1,..., t, as does the magnetic quantum number with respect to
the angular momentum, l, and, in this fashion, the t quantum number presents
itself indistinguishable from l. In effect, the spectrum of the hindered
rotator has the same (2t+1)-fold level multiplicity as the unperturbed one. For
small t values, the wave functions and excitation energies of the perturbed
rotator differ from the ordinary spherical harmonics, and the l(l+1) law,
respectively, while approaching them asymptotically with increasing t. In this
fashion the breaking of the rotational symmetry at the level of the
representation functions is opaqued by the level degeneracy. The model provides
a tool for the description of rotational bands with anomalously large gaps
between the ground state and its first excitation.Comment: 10 pages, 6 figures; Molecular Physics 201
Spacelike Wilson Loops at Finite Temperature
In the high temperature phase of Yang-Mills theories, large spatial Wilson
loops show area law behaviour with a string tension that grows with increasing
temperature. Within the framework of the commonly used string picture we use a
large scale expansion, which allows us to determine the string tension from
measurements of intermediate and symmetric Wilson loops.Comment: Tex file. No figures included. Obtainable from P. Lacock at email
address: [email protected]
Colombian fruit and vegetables recognition using convolutional neural networks and transfer learning
Automatic image recognition is a convenient option for labeling and categorizing fruits and vegetables in supermarkets. This paper proposes the design and implementation of an automatic classification system for Colombian fruits, by training a convolutional neural network. A database was created to train and test the system, which consisted of 4980 images, labeled in 22 classes, each corresponding to pictures of the same kind of fruit, trying to reproduce the variability of a real case scenario with occlusions, different positions, rotations, lightings, colors, etc., and the use of bags. On-training data augmentation was used to further increase the robustness of the model. Additionally, transfer learning was implemented by taking the parameters of a pretrained model used for fruit classification as the new initial parameters of the proposed convolutional network, achieving an increase of the classification accuracy compared with the same model when trained with random initial weights. The final classification accuracy of the network was 98.12% which matches the scores achieved on previous works that performed fruit classification on less challenging datasets. Considering top-3 classification we report an accuracy of 99.95%. © 2020 IOP Publishing Ltd. All rights reserved
From E_8 to F via T
We argue that T-duality and F-theory appear automatically in the E_8 gauge
bundle perspective of M-theory. The 11-dimensional supergravity four-form
determines an E_8 bundle. If we compactify on a two-torus, this data specifies
an LLE_8 bundle where LG is a centrally-extended loopgroup of G. If one of the
circles of the torus is smaller than sqrt(alpha') then it is also smaller than
a nontrivial circle S in the LLE_8 fiber and so a dimensional reduction on the
total space of the bundle is not valid. We conjecture that S is the circle on
which the T-dual type IIB theory is compactified, with the aforementioned torus
playing the role of the F-theory torus. As tests we reproduce the T-dualities
between NS5-branes and KK-monopoles, as well as D6 and D7-branes where we find
the desired F-theory monodromy. Using Hull's proposal for massive IIA, this
realization of T-duality allows us to confirm that the Romans mass is the
central extension of our LE_8. In addition this construction immediately
reproduces the conjectured formula for global topology change from T-duality
with H-flux.Comment: 25 pages, 4 eps figure
Localized Fermions and Anomaly Inflow via Deconstruction
We study fermion localization in gauge theory space. We consider four
dimensional product gauge groups in which light chiral fermions transform under
different gauge factors of the product group. This construction provides a
suppression of higher dimensional operators. For example, it can be used to
suppress dangerous proton decay operators. The anomalies associated with the
light chiral fermions are compensated by Wess-Zumino terms, which in the
continuum limit reproduce the five dimensional Chern-Simons term.Comment: 12 pages, minor changes to section
Exponentially Small Supersymmetry Breaking from Extra Dimensions
The supersymmetric ``shining'' of free massive chiral superfields in extra
dimensions from a distant source brane can trigger exponentially small
supersymmetry breaking on our brane of order e^{-2 pi R}, where R is the radius
of the extra dimensions. This supersymmetry breaking can be transmitted to the
superpartners in a number of ways, for instance by gravity or via the standard
model gauge interactions. The radius R can easily be stabilized at a size O(10)
larger that the fundamental scale. The models are extremely simple, relying
only on free, classical bulk dynamics to solve the hierarchy problem.Comment: RevTex, 1 figure. Comment on mu problem adde
Randomly dilute Ising model: A nonperturbative approach
The N-vector cubic model relevant, among others, to the physics of the
randomly dilute Ising model is analyzed in arbitrary dimension by means of an
exact renormalization-group equation. This study provides a unified picture of
its critical physics between two and four dimensions. We give the critical
exponents for the three-dimensional randomly dilute Ising model which are in
good agreement with experimental and numerical data. The relevance of the cubic
anisotropy in the O(N) model is also treated.Comment: 4 pages, published versio
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