589 research outputs found
Signatures of trans-Planckian dispersion in inflationary spectra
The primordial spectra are calculated using dispersion relations which
deviate from the relativistic one above a certain energy scale Lambda. We
determine the properties of the leading modifications with respect to the
standard spectra when Lambda is much greater than H, the Hubble scale during
inflation. To be generic, we parameterize the lowest order deviation from the
relativistic law by alpha, the power of P/Lambda where P is the proper
momentum. When working in the asymptotic vacuum, the leading modification
scales as (H/Lambda)^alpha for all alpha, except for a discrete set where the
power is higher. Moreover, this modification is robust against introducing
higher order terms in the dispersion relation. We then algebraically deduce the
modifications of scalar and tensor power spectra in slow roll inflation from
modifications calculated in de Sitter space. The modifications do not exhibit
oscillations unless the dispersion relation induces some non-adiabaticity near
a given scale. Finally, we explore the much less studied regime where H and
Lambda are comparable. Our results indicate that the project of reconstructing
the inflaton potential cannot be pursued without making some hypothesis about
the dispersion relation of the fluctuation modes.Comment: Version accepted for publication in PRD. 15 pages, 10 figures.
Comment on observational consequences adde
Leukocyte migration in experimental inflammatory bowel disease
Emigration of leukocytes from the circulation into tissue by transendothelial migration, is mediated subsequently by adhesion molecules such as selectins, chemokines and integrins. This multistep paradigm, with multiple molecular choices at each step, provides a diversity in signals. The influx of neutrophils, monocytes and lymphocytes into inflamed tissue is important in the pathogenesis of chronic inflammatory bowel disease. The importance of each of these groups of adhesion molecules in chronic inflammatory bowel disease, either in human disease or in animal models, will be discussed below. Furthermore, the possibilities of blocking these different steps in the process of leukocyte extravasation in an attempt to prevent further tissue damage, will be taken into account
Estime de soi et troubles psychiatriques Ă l'adolescence.
peer reviewedSelf-esteem refers to the individual's perception of his and her competence, value, and worthiness of respect. The early years are critical in forming a base of self-esteem; it develops as a result of positive or negative experiences during childhood. Self-esteem has been identified as an important parameter of adolescent development. This suggest the importance of considering self-esteem in adolescence. This study examined the different data on self-esteem of well adolescents and psychiatric adolescents.
The results are discusse
Experimental modulation of capsule size in Cryptococcus neoformans
Experimental modulation of capsule size is an important technique for the study of the virulence of the encapsulated pathogen Cryptococcus neoformans. In this paper, we summarize the techniques available for experimental modulation of capsule size in this yeast and describe improved methods to induce capsule size changes. The response of the yeast to the various stimuli is highly dependent on the cryptococcal strain. A high CO(2) atmosphere and a low iron concentration have been used classically to increase capsule size. Unfortunately, these stimuli are not reliable for inducing capsular enlargement in all strains. Recently we have identified new and simpler conditions for inducing capsule enlargement that consistently elicited this effect. Specifically, we noted that mammalian serum or diluted Sabouraud broth in MOPS buffer pH 7.3 efficiently induced capsule growth. Media that slowed the growth rate of the yeast correlated with an increase in capsule size. Finally, we summarize the most commonly used media that induce capsule growth in C. neoformans
The Cerenkov effect revisited: from swimming ducks to zero modes in gravitational analogs
We present an interdisciplinary review of the generalized Cerenkov emission
of radiation from uniformly moving sources in the different contexts of
classical electromagnetism, superfluid hydrodynamics, and classical
hydrodynamics. The details of each specific physical systems enter our theory
via the dispersion law of the excitations. A geometrical recipe to obtain the
emission patterns in both real and wavevector space from the geometrical shape
of the dispersion law is discussed and applied to a number of cases of current
experimental interest. Some consequences of these emission processes onto the
stability of condensed-matter analogs of gravitational systems are finally
illustrated.Comment: Lecture Notes at the IX SIGRAV School on "Analogue Gravity" in Como,
Italy from May 16th-21th, 201
Programmable Edge-to-Cloud Virtualization for 5G Media Industry: The 5G-MEDIA Approach
To ensure high Quality of Experience (QoE) for end users, many media applications require significant quantities of computing and network resources, making their realization challenging in resource constrained environments. In this paper, we present the approach of the 5G-MEDIA project, providing an integrated programmable service platform for the development, design and operations of media applications in 5G networks, facilitating media service management across the service life cycle. The platform offers tools to service developers for efficient development, testing and continuous correction of services. One step further, it provides a service virtualization platform offering horizontal services, such as a Media Service Catalogue and accounting services, as well as optimization mechanisms to flexibly adapt service operations to dynamic conditions with efficient use of infrastructure resources. The paper outlines three use cases where the platform was tested and validated
Understanding Hawking radiation from simple models of atomic Bose-Einstein condensates
This chapter is an introduction to the Bogoliubov theory of dilute Bose
condensates as applied to the study of the spontaneous emission of phonons in a
stationary condensate flowing at supersonic speeds. This emission process is a
condensed-matter analog of Hawking radiation from astrophysical black holes but
is derived here from a microscopic quantum theory of the condensate without any
use of the analogy with gravitational systems. To facilitate physical
understanding of the basic concepts, a simple one-dimensional geometry with a
stepwise homogenous flow is considered which allows for a fully analytical
treatment.Comment: 41 pages. to appear in the proceedings of the IX SIGRAV School on
'Analogue Gravity', Como (Italy), May 201
On Horava-Lifshitz "Black Holes"
The most general spherically symmetric solution with zero shift is found in
the non-projectable Horava-Lifshitz class of theories with general coupling
constants. It contains as special cases, spherically symmetric solutions found
by other authors earlier. It is found that the generic solution has
conventional (AdS, dS or flat) asymptotics with a universal 1/r tail. There are
several special cases where the asymptotics differ, including the detailed
balance choice of couplings. The conventional thermodynamics of this general
class of solutions is established by calculating the energy, temperature and
entropy. Although several of the solutions have conventional horizons, for
particles with ultra-luminal dispersion relations such solutions appear to be
horizonless.Comment: Latex 41 pages, 5 figure
Sensorineural hearing loss in Lassa fever: two case reports
<p>Abstract</p> <p>Introduction</p> <p>Lassa fever is an acute arena viral haemorrhagic fever with varied neurological sequelae. Sensorineural hearing loss is one of the rare complications which occur usually during the convalescent stage of the infection.</p> <p>Case presentation</p> <p>The cases of two female patients aged 19 and 43 years old, respectively, with clinical features suggestive of Lassa fever and confirmed by immunoserological/Lassa-virus-specific reverse transcriptase polymerase chain reaction are presented. Both patients developed severe sensorineural hearing loss at acute phases of the infections.</p> <p>Conclusion</p> <p>Sensorineural hearing loss from Lassa fever infections can occur in both acute and convalescent stages and is probably induced by an immune response.</p
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