390 research outputs found
Nonlinear equations for p-adic open, closed, and open-closed strings
We investigate the structure of solutions of boundary value problems for a
one-dimensional nonlinear system of pseudodifferential equations describing the
dynamics (rolling) of p-adic open, closed, and open-closed strings for a scalar
tachyon field using the method of successive approximations. For an open-closed
string, we prove that the method converges for odd values of p of the form
p=4n+1 under the condition that the solution for the closed string is known.
For p=2, we discuss the questions of the existence and the nonexistence of
solutions of boundary value problems and indicate the possibility of
discontinuous solutions appearing.Comment: 16 pages, 3 figure
Nonlocal Dynamics of p-Adic Strings
We consider the construction of Lagrangians that might be suitable for
describing the entire -adic sector of an adelic open scalar string. These
Lagrangians are constructed using the Lagrangian for -adic strings with an
arbitrary prime number . They contain space-time nonlocality because of the
d'Alembertian in argument of the Riemann zeta function. We present a brief
review and some new results.Comment: 8 page
Thermal Duality and Hagedorn Transition from p-adic Strings
We develop the finite temperature theory of p-adic string models. We find
that the thermal properties of these non-local field theories can be
interpreted either as contributions of standard thermal modes with energies
proportional to the temperature, or inverse thermal modes with energies
proportional to the inverse of the temperature, leading to a "thermal duality"
at leading order (genus one) analogous to the well known T-duality of string
theory. The p-adic strings also recover the asymptotic limits (high and low
temperature) for arbitrary genus that purely stringy calculations have yielded.
We also discuss our findings surrounding the nature of the Hagedorn transition.Comment: 4 pages and 4 figure
Zeta Nonlocal Scalar Fields
We consider some nonlocal and nonpolynomial scalar field models originated
from p-adic string theory. Infinite number of spacetime derivatives is
determined by the operator valued Riemann zeta function through d'Alembertian
in its argument. Construction of the corresponding Lagrangians L starts
with the exact Lagrangian for effective field of p-adic tachyon
string, which is generalized replacing p by arbitrary natural number n and then
taken a sum of over all n. The corresponding new objects we
call zeta scalar strings. Some basic classical field properties of these fields
are obtained and presented in this paper. In particular, some solutions of the
equations of motion and their tachyon spectra are studied. Field theory with
Riemann zeta function dynamics is interesting in its own right as well.Comment: 13 pages, submitted to Theoretical and Mathematical Physic
On p-Adic Sector of Adelic String
We consider construction of Lagrangians which are candidates for p-adic
sector of an adelic open scalar string. Such Lagrangians have their origin in
Lagrangian for a single p-adic string and contain the Riemann zeta function
with the d'Alembertian in its argument. In particular, we present a new
Lagrangian obtained by an additive approach which takes into account all p-adic
Lagrangians. The very attractive feature of this new Lagrangian is that it is
an analytic function of the d'Alembertian. Investigation of the field theory
with Riemann zeta function is interesting in itself as well.Comment: 10 pages. Presented at the 2nd Conf. on SFT and Related Topics,
Moscow, April 2009. Submitted to Theor. Math. Phy
Localization of the SFT inspired Nonlocal Linear Models and Exact Solutions
A general class of gravitational models driven by a nonlocal scalar field
with a linear or quadratic potential is considered. We study the action with an
arbitrary analytic function , which has both simple and double roots.
The way of localization of nonlocal Einstein equations is generalized on models
with linear potentials. Exact solutions in the Friedmann-Robertson-Walker and
Bianchi I metrics are presented.Comment: 20 pages, 3 figures, published in the proceedings of the VIII
International Workshop "Supersymmetries and Quantum Symmetries" (SQS'09),
Dubna, Russia, July 29 - August 3, 2009, http://theor.jinr.ru/~sqs09
p-Adic and Adelic Harmonic Oscillator with Time-Dependent Frequency
The classical and quantum formalism for a p-adic and adelic harmonic
oscillator with time-dependent frequency is developed, and general formulae for
main theoretical quantities are obtained. In particular, the p-adic propagator
is calculated, and the existence of a simple vacuum state as well as adelic
quantum dynamics is shown. Space discreteness and p-adic quantum-mechanical
phase are noted.Comment: 10 page
Multiāinstrument Observations of IonāNeutral Coupling in the Dayside Cusp
Using data from the Scanning Doppler Imager, the Super Dual Auroral Radar Network, the EISCAT Svalbard Radar and an auroral allāsky imager, we examine an instance of Fāregion neutral winds which have been influenced by the presence of poleward moving auroral forms near the dayside cusp region. We observe a reduction in the time taken for the ionādrag force to reāorientate the neutrals into the direction of the convective plasma (on the order of minutes), compared to before the auroral activity began. Additionally, because the ionosphere near the cusp is influenced much more readily by changes in the solar wind via dayside reconnection, we observe the neutrals responding to an interplanetary magnetic field change within minutes of it occurring. This has implications on the rate that energy is deposited into the ionosphere via Joule heating, which we show to become dampened by the neutral winds
Does present use of cardiovascular medication reflect elevated cardiovascular risk scores estimated ten years ago? A population based longitudinal observational study
Background
It is desirable that those at highest risk of cardiovascular disease should have priority for preventive measures, eg. treatment with prescription drugs to modify their risk. We wanted to investigate to what extent present use of cardiovascular medication (CVM) correlates with cardiovascular risk estimated by three different risk scores (Framingham, SCORE and NORRISK) ten years ago.
Methods
Prospective logitudinal observational study of 20 252 participants in The Hordaland Health Study born 1950-57, not using CVM in 1997-99. Prescription data obtained from The Norwegian Prescription Database in 2008.
Results
26% of men and 22% of women aged 51-58 years had started to use some CVM during the previous decade. As a group, persons using CVM scored significantly higher on the risk algorithms Framingham, SCORE and NORRISK compared to those not treated. 16-20% of men and 20-22% of women with risk scores below the high-risk thresholds for the three risk scores were treated with CVM, while 60-65% of men and 25-45% of women with scores above the high-risk thresholds received no treatment. Among women using CVM, only 2.2% (NORRISK), 4.4% (SCORE) and 14.5% (Framingham) had risk scores above the high-risk values. Low education, poor self-reported general health, muscular pains, mental distress (in females only) and a family history of premature cardiovascular disease correlated with use of CVM. Elevated blood pressure was the single factor most strongly predictive of CVM treatment.
Conclusion
Prescription of CVM to middle-aged individuals by large seems to occur independently of estimated total cardiovascular risk, and this applies especially to females
Increasing Dominance - the Role of Advertising, Pricing and Product Design
Despite the empirical relevance of advertising strategies in concentrated markets, the economics literature is largely silent on the effect of persuasive advertising
strategies on pricing, market structure and increasing (or decreasing) dominance. In a simple model of persuasive advertising and pricing with differentiated goods,
we analyze the interdependencies between ex-ante asymmetries in consumer appeal, advertising and prices. Products with larger initial appeal to consumers will
be advertised more heavily but priced at a higher level - that is, advertising and price discounts are strategic substitutes for products with asymmetric initial appeal.
We find that the escalating effect of advertising dominates the moderating effect of pricing so that post-competition market shares are more asymmetric than pre-competition differences in consumer appeal. We further find that collusive advertising (but competitive pricing) generates the same market outcomes, and that network effects lead to even more extreme market outcomes, both directly and via
the effect on advertising
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