5,281 research outputs found
A detailed next-to-leading order QCD analysis of deeply virtual Compton scattering observables
We present a detailed next-to-leading order (NLO) leading twist QCD analysis
of deeply virtual Compton scattering (DVCS) observables, for several different
input scenarios, in the MS-bar scheme. We discuss the size of the NLO effects
and the behavior of the observables in skewedness , momentum transfer,
, and photon virtuality, . We present results on the amplitude
level for unpolarized and longitudinally polarized lepton probes, and
unpolarized and longitudinally polarized proton targets. We make predictions
for various asymmetries and for the DVCS cross section and compare with the
available data.Comment: 38 pages, 40 figures, revtex, published version. Substantially
shortened for publication: appendices and ten figures removed, sections III,
IV and V condensed. Several physics points improved or corrected in response
to referee's report. Incorrect citations and typo in eq.(3) correcte
On the Number of Membranes in Unary P Systems
We consider P systems with a linear membrane structure working on objects
over a unary alphabet using sets of rules resembling homomorphisms. Such a
restricted variant of P systems allows for a unique minimal representation of
the generated unary language and in that way for an effective solution of the
equivalence problem. Moreover, we examine the descriptional complexity of unary
P systems with respect to the number of membranes
An implementation of the look-ahead Lanczos algorithm for non-Hermitian matrices
The nonsymmetric Lanczos method can be used to compute eigenvalues of large sparse non-Hermitian matrices or to solve large sparse non-Hermitian linear systems. However, the original Lanczos algorithm is susceptible to possible breakdowns and potential instabilities. An implementation is presented of a look-ahead version of the Lanczos algorithm that, except for the very special situation of an incurable breakdown, overcomes these problems by skipping over those steps in which a breakdown or near-breakdown would occur in the standard process. The proposed algorithm can handle look-ahead steps of any length and requires the same number of matrix-vector products and inner products as the standard Lanczos process without look-ahead
Autonomous Inspections of Utility Networks
Field inspections of utility network assets are a critical aspect of maintaining the quality and integrity of services provided by a utility. Currently, such inspections are performed largely by human inspectors. Such manual inspections are time-consuming, expensive, potentially dangerous to the inspectors and the surrounding public, subject to human error, disruptive to neighboring communities, and lack the speedy response needed in a disaster scenario. This disclosure describes a machine-based inspection mechanism for utility networks, based on, for example, autonomous or remotely-operated drones with the capability to perform intricate inspections at difficult-to-reach regions and heights. The inspection tasks including, for example, navigation routes, assets and parameters to be inspected, etc. are determined, for example, by a machine learner that has access to real-time and historical data from a variety of relevant sources
Matter Enhanced Neutrino Oscillations with a Realistic Earth Density Profile
We have investigated matter enhanced neutrino oscillations with a
mantle-core-mantle step function and a realistic Earth matter density profile
in both a two and a three neutrino scenario. We found that the realistic Earth
matter density profile can be well approximated with the mantle-core-mantle
step function and that there could be an influence on the oscillation channel
due to resonant enhancement of one of the mixing angles.Comment: 8 pages, 5 figures (PostScript), MPLA LaTe
Lessons learned from introducing social media use in undergraduate economics research
The research process and associated literacy requirements are often unfamiliar and daunting obstacles for undergraduate students. The use of social media has the potential to assist research training and encourage active learning, social inclusion and student engagement. This paper documents the lessons learned from developing a blended learning model for undergraduate economics research incorporating social media blogging at a regional university in Australia. Student surveys, interviews with colleagues and students, in addition to a review of higher education literature highlight key issues associated with the choice of social media platform, need for clarity in assessment design, and assumptions of student proficiency with social media. The process of applying these findings to the design of a new subject are documented, highlighting a number of unanticipated institutional obstacles. It is hope that our findings will be practical and useful for instructors to consider when contemplating the introduction of social media to their teaching and learning practice
Fusion of aerial images and sensor data from a ground vehicle for improved semantic mapping
This work investigates the use of semantic information to link ground level occupancy maps and aerial images. A ground level semantic map, which shows open ground and indicates the probability of cells being occupied by walls of buildings, is obtained by a mobile robot equipped with an omnidirectional camera, GPS and a laser range finder. This semantic information is used for local and global segmentation of an aerial image. The result is a map where the semantic information has been extended beyond the range of the robot sensors and predicts where the mobile robot can find buildings and potentially driveable ground
Electro-Magnetic Earthquake Bursts and Critical Rupture of Peroxy Bond Networks in Rocks
We propose a mechanism for the low frequency electromagnetic emissions and
other electromagnetic phenomena which have been associated with earthquakes.
The mechanism combines the critical earthquake concept and the concept of crust
acting as a charging electric battery under increasing stress. The electric
charges are released by activation of dormant charge carriers in the oxygen
anion sublattice, called peroxy bonds or positive hole pairs (PHP), where a PHP
represents an with ,
i.e. an in a matrix of of silicates. We propose that PHP are
activated by plastic deformations during the slow cooperative build-up of
stress and the increasingly correlated damage culminating in a large
``critical'' earthquake. Recent laboratory experiments indeed show that
stressed rocks form electric batteries which can release their charge when a
conducting path closes the equivalent electric circuit. We conjecture that the
intermittent and erratic occurrences of EM signals are a consequence of the
progressive build-up of the battery charges in the Earth crust and their
erratic release when crack networks are percolating throughout the stressed
rock volumes, providing a conductive pathway for the battery currents to
discharge. EM signals are thus expected close to the rupture, either slightly
before or after, that is, when percolation is most favored.Comment: 17 pages with 3 figures, extended discussion with 1 added figure and
162 references. The new version provides both a synthesis of two theories and
a review of the fiel
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