7,310 research outputs found
Pre-Big Bang Scenario on Self-T-Dual Bouncing Branes
We consider a new class of 5-dimensional dilatonic actions which are
invariant under T-duality transformations along three compact coordinates,
provided that an appropriate potential is chosen. We show that the invariance
remains when we add a boundary term corresponding to a moving 3-brane, and we
study the effects of the T-duality symmetry on the brane cosmological
equations. We find that T-duality transformations in the bulk induce scale
factor duality on the brane, together with a change of sign of the pressure of
the brane cosmological matter. However, in a remarkable analogy with the
Pre-Big Bang scenario, the cosmological equations are unchanged. Finally, we
propose a model where the dual phases are connected through a scattering of the
brane induced by an effective potential. We show how this model can realise a
smooth, non-singular transition between a pre-Big Bang superinflationary
Universe and a post-Big Bang accelerating Universe.Comment: 18 pages, minor typos corrected, Sec. 2 expanded with more details on
the self-T-dual background, Sec.4 and 5 revised accordingly. Version to
appear on JCA
An algorithmic approach to the existence of ideal objects in commutative algebra
The existence of ideal objects, such as maximal ideals in nonzero rings,
plays a crucial role in commutative algebra. These are typically justified
using Zorn's lemma, and thus pose a challenge from a computational point of
view. Giving a constructive meaning to ideal objects is a problem which dates
back to Hilbert's program, and today is still a central theme in the area of
dynamical algebra, which focuses on the elimination of ideal objects via
syntactic methods. In this paper, we take an alternative approach based on
Kreisel's no counterexample interpretation and sequential algorithms. We first
give a computational interpretation to an abstract maximality principle in the
countable setting via an intuitive, state based algorithm. We then carry out a
concrete case study, in which we give an algorithmic account of the result that
in any commutative ring, the intersection of all prime ideals is contained in
its nilradical
Decoration of nanovesicles with pH (low) insertion peptide (pHLIP) for targeted delivery
Acidity at surface of cancer cells is a hallmark of tumor microenvironments, which does not depend on tumor perfusion, thus it may serve as a general biomarker for targeting tumor cells. We used the pH (low) insertion peptide (pHLIP) for decoration of liposomes and niosomes. pHLIP senses pH at the surface of cancer cells and inserts into the membrane of targeted cells, and brings nanomaterial to close proximity of cellular membrane. DMPC liposomes and Tween 20 or Span 20 niosomes with and without pHLIP in their coating were fully characterized in order to obtain fundamental understanding on nanocarrier features and facilitate the rational design of acidity sensitive nanovectors. The samples stability over time and in presence of serum was demonstrated. The size, ζ-potential, and morphology of nanovectors, as well as their ability to entrap a hydrophilic probe and modulate its release were investigated. pHLIP decorated vesicles could be useful to obtain a prolonged (modified) release of biological active substances for targeting tumors and other acidic diseased tissues
Additive energy forward curves in a Heath-Jarrow-Morton framework
One of the peculiarities of power and gas markets is the delivery mechanism
of forward contracts. The seller of a futures contract commits to deliver, say,
power, over a certain period, while the classical forward is a financial
agreement settled on a maturity date. Our purpose is to design a
Heath-Jarrow-Morton framework for an additive, mean-reverting, multicommodity
market consisting of forward contracts of any delivery period. The main
assumption is that forward prices can be represented as affine functions of a
universal source of randomness. This allows us to completely characterize the
models which prevent arbitrage opportunities: this boils down to finding a
density between a risk-neutral measure , such that the prices of
traded assets like forward contracts are true -martingales, and the
real world probability measure , under which forward prices are
mean-reverting. The Girsanov kernel for such a transformation turns out to be
stochastic and unbounded in the diffusion part, while in the jump part the
Girsanov kernel must be deterministic and bounded: thus, in this respect, we
prove two results on the martingale property of stochastic exponentials. The
first allows to validate measure changes made of two components: an
Esscher-type density and a Girsanov transform with stochastic and unbounded
kernel. The second uses a different approach and works for the case of
continuous density. We apply this framework to two models: a generalized
Lucia-Schwartz model and a cross-commodity cointegrated market.Comment: 28 page
Hubungan Pengetahuan Dengan Tingkat Kecemasan Ibu Yang Anaknya Di Rawat Rsup Prof. Dr. R. D. Kandou Manado
. Knowledge is the result of the idea and someone did this happen after sensing on a particular object. Anxiety is a normal thing that happens in the growth, changes, new experiences and discoveries can accompany meaning of life and self-identity. The higher one's education will be more easily and able to deal with stress.Individually anxious can interfere especially with the lack of knowledge of the problems faced. The purpose of this study is to find the relationship of knowledge about dengue fever with a mother whose son is anxiety levels treated parts department Prof children Dr. R. D. Kandou Manado. This study used a questionnaire rating their knowledge and Hamilton Anxiety Scale (HARS) with a sample of 71 respondents.Based on the results of the study found that there are 32 good knowledgeable mothers (45,07%) were knowledgeable mothers 39 (54,93%). While there were 59 maternal anxiety (83,10%) severe anxiety, there were 12 mothers (16,90%). Based on statistics by using Fisher's Exact Test is used as an alternative test of the Chi Square test are not eligible where one column value must be at least 5,41. Based on the analysis at 95% confidence level and error rate α = 0.05 shows the p-value = 0.000 <α = 0.05 level. Therefore we can conclude that H0 is rejected and Ha is accepted that there is a significant correlation between maternal knowledge about dengue fever with maternal anxiety levels that treated her son Prof parts. Dr. R. D.Kandou Manado
Swimming is never without risk: opening up on learning through activism and research
This article examines my own becoming as Elisabeth and as a researcher. It is about working as a support worker, coaching teams that are trying to realize inclusive education for a child, and my PhD process, which relies on these practices. My intention here is to unfold several aspects, blockages, possibilities, and tensions that can make sense of my messy struggle. The never-ending learning through working with people, listening to their stories, and taking responsibility are important ingredients of my engagement. It is necessary to provide insights and justify my multiple positions to avoid falling into a narcissistic trap. In doing so, I will seek help from Levinas and in concepts of Deleuze and Guattari to (re-)construct my own understanding
Linear Sigma EFT for Nearly Conformal Gauge Theories
We construct a generalized linear sigma model as an effective field theory
(EFT) to describe nearly conformal gauge theories at low energies. The work is
motivated by recent lattice studies of gauge theories near the conformal
window, which have shown that the lightest flavor-singlet scalar state in the
spectrum () can be much lighter than the vector state () and
nearly degenerate with the PNGBs () over a large range of quark masses.
The EFT incorporates this feature. We highlight the crucial role played by the
terms in the potential that explicitly break chiral symmetry. The explicit
breaking can be large enough so that a limited set of additional terms in the
potential can no longer be neglected, with the EFT still weakly coupled in this
new range. The additional terms contribute importantly to the scalar and pion
masses. In particular, they relax the inequality , allowing for consistency with current lattice data.Comment: 9 pages, 1 figure, published versio
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