2,249 research outputs found
Mice lacking endothelial ACE: normal blood pressure with elevated angiotensin II
Journal ArticleRecently, the concept of local renin-angiotensin systems (RAS) capable of generating angiotensin II apart from the circulation has received considerable attention. To investigate this, we generated ACE 1/3 mice in which one allele of ACE is null and the second allele was engineered to express ACE on the surface of hepatocytes. ACE 1/3 mice express no endothelial ACE and lack ACE within the lungs. Their kidneys contain <7.8% the enzyme levels present in control mice. Plasma conversion of angiotensin I to angiotensin II was 43.3% normal. The baseline blood pressure and renal function of the ACE 1/3 mice were normal, probably as a function of a marked increase of both plasma angiotensin I and angiotensin II. When exposed to 2 weeks of a salt-free diet (a stress diet stimulating the RAS), blood pressure in ACE 1/3 mice decreased to 92.3+2.0 mm Hg, a level significantly lower than that of wild-type control mice. The ACE 1/3 mice demonstrate the plasticity of the RAS and show that significant compensation is required to maintain normal, basal blood pressure in a mouse with an impaired local vascular and renal RAS. (Hypertension. 2003;41:313- 321.
Scaling and universality in coupled driven diffusive models
Inspired by the physics of magnetohydrodynamics (MHD) a simplified coupled
Burgers-like model in one dimension (1d), a generalization of the Burgers model
to coupled degrees of freedom, is proposed to describe 1dMHD. In addition to
MHD, this model serves as a 1d reduced model for driven binary fluid mixtures.
Here we have performed a comprehensive study of the universal properties of the
generalized d-dimensional version of the reduced model. We employ both
analytical and numerical approaches. In particular, we determine the scaling
exponents and the amplitude-ratios of the relevant two-point time-dependent
correlation functions in the model. We demonstrate that these quantities vary
continuously with the amplitude of the noise cross-correlation. Further our
numerical studies corroborate the continuous dependence of long wavelength and
long time-scale physics of the model on the amplitude of the noise
cross-correlations, as found in our analytical studies. We construct and
simulate lattice-gas models of coupled degrees of freedom in 1d, belonging to
the universality class of our coupled Burgers-like model, which display similar
behavior. We use a variety of numerical (Monte-Carlo and Pseudospectral
methods) and analytical (Dynamic Renormalization Group, Self-Consistent
Mode-Coupling Theory and Functional Renormalization Group) approaches for our
work. The results from our different approaches complement one another.
Possible realizations of our results in various nonequilibrium models are
discussed.Comment: To appear in JSTAT (2009); 52 pages in JSTAT format. Some figure
files have been replace
Joint Statement on Pediatric Education at Schools of Pharmacy
Providing health care for children is a unique specialty, and pediatric patients represent approximately 25% of the population. Education of pharmacy students on patients across the lifespan is required by current Accreditation Council for Pharmacy Education standards and outcomes; thus, it is essential that pharmacy students gain a proficiency in caring for children. A collaborative panel of pediatric faculty members from schools and colleges of pharmacy was established to review the current literature regarding pediatric education in Doctor of Pharmacy curricula and establish updated recommendations for the provision of pediatric pharmacy education. This statement outlines five recommendations supporting inclusion of pediatric content and skills in Doctor of Pharmacy curricula
Construction of a \u3cem\u3eSonchus Yellow Net Virus\u3c/em\u3e Minireplicon: A Step Toward Reverse Genetic Analysis of Plant Negative-Strand RNA Viruses
Reverse genetic analyses of negative-strand RNA (NSR) viruses have provided enormous advances in our understanding of animal viruses over the past 20 years, but technical difficulties have hampered application to plant NSR viruses. To develop a reverse genetic approach for analysis of plant NSR viruses, we have engineered Sonchus yellow net nucleorhabdovirus (SYNV) minireplicon (MR) reporter cassettes for Agrobacterium tumefaciens expression in Nicotiana benthamiana leaves. Fluorescent reporter genes substituted for the SYNV N and P protein open reading frames (ORFs) exhibited intense single-cell foci throughout regions of infiltrated leaves expressing the SYNV MR derivatives and the SYNV nucleocapsid (N), phosphoprotein (P), and polymerase (L) proteins. Genomic RNA and mRNA transcription was detected for reporter genes substituted for both the SYNV N and P ORFs. These activities required expression of the N, P, and L core proteins in trans and were enhanced by codelivery of viral suppressor proteins that interfere with host RNA silencing. As is the case with other members of the Mononegavirales, we detected polar expression of fluorescent proteins and chloramphenicol acetyltransferase substitutions for the N and P protein ORFs. We also demonstrated the utility of the SYNV MR system for functional analysis of SYNV core proteins in trans and the cis-acting leader and trailer sequence requirements for transcription and replication. This work provides a platform for construction of more complex SYNV reverse genetic derivatives and presents a general strategy for reverse genetic applications with other plant NSR viruses
Quasi-linear regime and rare-event tails of decaying Burgers turbulence
We study the decaying Burgers dynamics in dimensions for random Gaussian
initial conditions. We focus on power-law initial energy spectra, such that the
system shows a self-similar evolution. This is the case of interest for the
"adhesion model" in cosmology and a standard framework for "decaying Burgers
turbulence". We briefly describe how the system can be studied through
perturbative expansions at early time or large scale (quasi-linear regime).
Next, we develop a saddle-point method, based on spherical instantons, that
allows to obtain the asymptotic probability distributions \cP(\eta_r) and
\cP(\ctheta_r), of the density and velocity increment over spherical cells,
reached in the quasi-linear regime. Finally, we show how this approach can be
extended to take into account the formation of shocks and we derive the
rare-event tails of these probability distributions, at any finite time and
scale. This also gives the high-mass tail of the mass function of point-like
singularities (shocks in the one dimensional case).Comment: 32 page
Canonical phase space approach to the noisy Burgers equation: Probability distributions
We present a canonical phase space approach to stochastic systems described
by Langevin equations driven by white noise. Mapping the associated
Fokker-Planck equation to a Hamilton-Jacobi equation in the nonperturbative
weak noise limit we invoke a {\em principle of least action} for the
determination of the probability distributions. We apply the scheme to the
noisy Burgers and KPZ equations and discuss the time-dependent and stationary
probability distributions. In one dimension we derive the long-time skew
distribution approaching the symmetric stationary Gaussian distribution. In the
short-time region we discuss heuristically the nonlinear soliton contributions
and derive an expression for the distribution in accordance with the directed
polymer-replica and asymmetric exclusion model results. We also comment on the
distribution in higher dimensions.Comment: 18 pages Revtex file, including 8 eps-figures, submitted to Phys.
Rev.
Event-related alpha suppression in response to facial motion
This article has been made available through the Brunel Open Access Publishing Fund.While biological motion refers to both face and body movements, little is known about the visual perception of facial motion. We therefore examined alpha wave suppression as a reduction in power is thought to reflect visual activity, in addition to attentional reorienting and memory processes. Nineteen neurologically healthy adults were tested on their ability to discriminate between successive facial motion captures. These animations exhibited both rigid and non-rigid facial motion, as well as speech expressions. The structural and surface appearance of these facial animations did not differ, thus participants decisions were based solely on differences in facial movements. Upright, orientation-inverted and luminance-inverted facial stimuli were compared. At occipital and parieto-occipital regions, upright facial motion evoked a transient increase in alpha which was then followed by a significant reduction. This finding is discussed in terms of neural efficiency, gating mechanisms and neural synchronization. Moreover, there was no difference in the amount of alpha suppression evoked by each facial stimulus at occipital regions, suggesting early visual processing remains unaffected by manipulation paradigms. However, upright facial motion evoked greater suppression at parieto-occipital sites, and did so in the shortest latency. Increased activity within this region may reflect higher attentional reorienting to natural facial motion but also involvement of areas associated with the visual control of body effectors. © 2014 Girges et al
Soliton approach to the noisy Burgers equation: Steepest descent method
The noisy Burgers equation in one spatial dimension is analyzed by means of
the Martin-Siggia-Rose technique in functional form. In a canonical formulation
the morphology and scaling behavior are accessed by mean of a principle of
least action in the asymptotic non-perturbative weak noise limit. The ensuing
coupled saddle point field equations for the local slope and noise fields,
replacing the noisy Burgers equation, are solved yielding nonlinear localized
soliton solutions and extended linear diffusive mode solutions, describing the
morphology of a growing interface. The canonical formalism and the principle of
least action also associate momentum, energy, and action with a
soliton-diffusive mode configuration and thus provides a selection criterion
for the noise-induced fluctuations. In a ``quantum mechanical'' representation
of the path integral the noise fluctuations, corresponding to different paths
in the path integral, are interpreted as ``quantum fluctuations'' and the
growth morphology represented by a Landau-type quasi-particle gas of ``quantum
solitons'' with gapless dispersion and ``quantum diffusive modes'' with a gap
in the spectrum. Finally, the scaling properties are dicussed from a heuristic
point of view in terms of a``quantum spectral representation'' for the slope
correlations. The dynamic eponent z=3/2 is given by the gapless soliton
dispersion law, whereas the roughness exponent zeta =1/2 follows from a
regularity property of the form factor in the spectral representation. A
heuristic expression for the scaling function is given by spectral
representation and has a form similar to the probability distribution for Levy
flights with index .Comment: 30 pages, Revtex file, 14 figures, to be submitted to Phys. Rev.
Minimum action method for the Kardar-Parisi-Zhang equation
We apply a numerical minimum action method derived from the Wentzell-Freidlin
theory of large deviations to the Kardar-Parisi-Zhang equation for a growing
interface. In one dimension we find that the switching scenario is determined
by the nucleation and subsequent propagation of facets or steps, corresponding
to moving domain walls or growth modes in the underlying noise driven Burgers
equation. The transition scenario is in accordance with recent analytical
studies of the one dimensional Kardar-Parisi-Zhang equation in the asymptotic
weak noise limit. We also briefly discuss transitions in two dimensions.Comment: 26 pages (revtex) and 18 figures (eps
Kepler eclipsing binary stars. VII. the catalogue of eclipsing binaries found in the entire Kepler data set
The primary Kepler Mission provided nearly continuous monitoring of ~200,000 objects with unprecedented photometric precision. We present the final catalog of eclipsing binary systems within the 105 deg2 Kepler field of view. This release incorporates the full extent of the data from the primary mission (Q0-Q17 Data Release). As a result, new systems have been added, additional false positives have been removed, ephemerides and principal parameters have been recomputed, classifications have been revised to rely on analytical models, and eclipse timing variations have been computed for each system. We identify several classes of systems including those that exhibit tertiary eclipse events, systems that show clear evidence of additional bodies, heartbeat systems, systems with changing eclipse depths, and systems exhibiting only one eclipse event over the duration of the mission. We have updated the period and galactic latitude distribution diagrams and included a catalog completeness evaluation. The total number of identified eclipsing and ellipsoidal binary systems in the Kepler field of view has increased to 2878, 1.3% of all observed Kepler targets
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