817 research outputs found
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Backup and recovery plan for HANDI 2000 business management system
The purpose of this Backup and Recovery Plan (BRP) is to provide guidelines for backup and recovery requirements of HANDI 2000 [Hanford Data Integration 2000] file systems and databases. The methods used to accomplish this are not new. The intent is to use the existing processes and procedures where possible to meet the needs of the HANDI 2000 System
Predicting Survival of East Texas Loblolly and Slash Pine Plantations Infected with Fusiform Rust
Repeated measurement during 1982-1992 of East Texas Pine Plantation Research Project permanent plots in loblolly( Pinus taedaL .) and slash( Pinus elliottii Engelm.) pine plantations throughout East Texas were used to develop equations for predicting the future number of trees per acre. A typical condition of East Texas pine plantations is the incidence of fusiform rust( Cronatrium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme). A regression procedure for fitting nonlinear systems of equations was used to fit survival models that considered the possibility that trees with no rust galls on the stem could either (1) remain uninfected and alive, (2) become infected yet still alive or (3) die. For infected stem so, only two possible outcomes were considered in the model:(1) remain infected and alive or (2) die.Analyses of the differences between predicted and observed values indicated no adverse trends for either of the two species. Apparently the models do represent observed survival patterns.South J. Appl. For. 20(1):30-35
Preventing young farmers from leaving the farm: investigating the effectiveness of the young farmer payment using a behavioural approach
The number of young farmers has decreased over recent decades in several developed countries such as the
United States and European countries. A recent strategy adopted by the European Union to address the resulting
age imbalance is the Young Farmer Payment which provides an additional payment on top of the average basic
payment introduced in the last Common Agricultural Policy reform. The objective of this study is to determine,
by means of a behavioural approach, how this payment in
fl
uenced the incentives of young farmers to stay in the
farm. Using the endogenous succession cycle model and the structural modelling technique, we found that the
payment a
ff
ected young farmers
’
willingness to stay through its in
fl
uence on non-economic motivational goals.
However, we also found that there are other factors that can be even more in
fl
uential, such as pessimism about
farming, community and family integration, participation in decision making, and the opinion of neighbours,
among others. Based on the results, we argue that similar policies could be adopted in other countries, although
policies would be more e
ff
ective in addressing age imbalances if they are accompanied with complementary
strategies aimed to deal with the identi
fi
ed social and psychological considerations
Transverse momentum dependence in gluon distribution and fragmentation functions
We investigate the twist two gluon distribution functions for spin 1/2
hadrons, emphasizing intrinsic transverse momentum of the gluons. These
functions are relevant in leading order in the inverse hard scale in scattering
processes such as inclusive leptoproduction or Drell-Yan scattering, or more
general in hard processes in which at least two hadrons are involved. They show
up in azimuthal asymmetries. For future estimates of such observables, we
discuss specific bounds on these functions.Comment: 14 pages, revtex, 7 Postscript figure
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
Polymer Shape Anisotropy and the Depletion Interaction
We calculate the second and third virial coefficients of the effective
sphere-sphere interaction due to polymer depletion. By utilizing the anisotropy
of a typical polymer conformation, we can consider polymers that are roughly
the same size as the spherical inclusions. We argue that recent experiments can
confirm this anisotropy.Comment: 4 pages, 4 eps figures, RevTe
Universality of Z3 parafermions via edge-mode interaction and quantum simulation of topological space evolution with Rydberg atoms
Parafermions are Zn generalizations of Majorana quasiparticles, with fractional non-Abelian statistics. They can be used to encode topological qudits and perform Clifford operations by their braiding. Here we investigate the generation of quantum gates by allowing Z3 parafermions to interact in order to achieve universality. In particular, we study the form of the nontopological gate that arises through direct short-range interaction of the parafermion edge modes in a Z3 parafermion chain. We show that such an interaction gives rise to a dynamical phase gate on the encoded ground space, generating a non-Clifford gate which can be tuned to belong to even levels of the Clifford hierarchy. We illustrate how to access highly noncontextual states using this dynamical gate. Finally, we propose an experiment that simulates the braiding and dynamical evolutions of the Z3 topological states with Rydberg atom technology
Null energy condition and superluminal propagation
We study whether a violation of the null energy condition necessarily implies
the presence of instabilities. We prove that this is the case in a large class
of situations, including isotropic solids and fluids relevant for cosmology. On
the other hand we present several counter-examples of consistent effective
field theories possessing a stable background where the null energy condition
is violated. Two necessary features of these counter-examples are the lack of
isotropy of the background and the presence of superluminal modes. We argue
that many of the properties of massive gravity can be understood by associating
it to a solid at the edge of violating the null energy condition. We briefly
analyze the difficulties of mimicking in scalar tensor theories of
gravity.Comment: 46 pages, 6 figure
Some Relations between Twisted K-theory and E8 Gauge Theory
Recently, Diaconescu, Moore and Witten provided a nontrivial link between
K-theory and M-theory, by deriving the partition function of the Ramond-Ramond
fields of Type IIA string theory from an E8 gauge theory in eleven dimensions.
We give some relations between twisted K-theory and M-theory by adapting the
method of Diaconescu-Moore-Witten and Moore-Saulina. In particular, we
construct the twisted K-theory torus which defines the partition function, and
also discuss the problem from the E8 loop group picture, in which the
Dixmier-Douady class is the Neveu-Schwarz field. In the process of doing this,
we encounter some mathematics that is new to the physics literature. In
particular, the eta differential form, which is the generalization of the eta
invariant, arises naturally in this context. We conclude with several open
problems in mathematics and string theory.Comment: 23 pages, latex2e, corrected minor errors and typos in published
versio
Supersymmetric Models with Higher Dimensional Operators
In 4D renormalisable theories, integrating out massive states generates in
the low energy effective action higher dimensional operators (derivative or
otherwise). Using a superfield language it is shown that a 4D N=1
supersymmetric theory with higher derivative operators in either the Kahler or
the superpotential part of the Lagrangian and with an otherwise arbitrary
superpotential, is equivalent to a 4D N=1 theory of second order (i.e. without
higher derivatives) with additional superfields and renormalised interactions.
We provide examples where a free theory with trivial supersymmetry breaking
provided by a linear superpotential becomes, in the presence of higher
derivatives terms and in the second order version, a non-trivial interactive
one with spontaneous supersymmetry breaking. The couplings of the equivalent
theory acquire a threshold correction through their dependence on the scale of
the higher dimensional operator(s). The scalar potential in the second order
theory is not necessarily positive definite, and one can in principle have a
vanishing potential with broken supersymmetry. We provide an application to
MSSM and argue that at tree-level and for a mass scale associated to a higher
derivative term in the TeV range, the Higgs mass can be lifted above the
current experimental limits.Comment: 36 pages; some clarifications and references adde
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