235 research outputs found
Behavioral approach to robustness analysis
This paper introduces a general and powerful framework for modeling and analysis of uncertain systems. One immediate concrete result of this work is a practical method for computing robust performance in the presence of norm-bounded perturbations and both norm-bounded and white-noise disturbances
Approximate behaviors
The motivation for this paper is to contribute to a unified approach to modeling, realization, approximation and analysis for systems with a rich class of uncertainty structures. The specific focus is on what is the appropriate framework to model components with uncertainty, and what is the appropriate notion of approximation for such components. Components and systems are conceptualized in terms of their behaviors, which can be specified by parametrized equations. More questions are posed than are answered
Generic versus brand-name drugs used in cardiovascular diseases
This meta-analysis aimed to compare the efficacy and adverse events, either serious or mild/moderate, of all generic versus brand-name cardiovascular medicines. We searched randomized trials in MEDLINE, Scopus, EMBASE, Cochrane Controlled Clinical Trial Register, and ClinicalTrials.gov (last update December 1, 2014). Attempts were made to contact the investigators of all potentially eligible trials. Two investigators independently extracted and analyzed soft (including systolic blood pressure, LDL cholesterol, and others) and hard efficacy outcomes (including major cardiovascular adverse events and death), minor/moderate and serious adverse events. We included 74 randomized trials; 53 reported ≥1 efficacy outcome (overall sample 3051), 32 measured mild/moderate adverse events (n = 2407), and 51 evaluated serious adverse events (n = 2892). We included trials assessing ACE inhibitors (n = 12), anticoagulants (n = 5), antiplatelet agents (n = 17), beta-blockers (n = 11), calcium channel blockers (n = 7); diuretics (n = 13); statins (n = 6); and others (n = 3). For both soft and hard efficacy outcomes, 100 % of the trials showed non-significant differences between generic and brand-name drugs. The aggregate effect size was 0.01 (95 % CI -0.05; 0.08) for soft outcomes; -0.06 (-0.71; 0.59) for hard outcomes. All but two trials showed non-significant differences in mild/moderate adverse events, and aggregate effect size was 0.07 (-0.06; 0.20). Comparable results were observed for each drug class and in each stratified meta-analysis. Overall, 8 serious possibly drug-related adverse events were reported: 5/2074 subjects on generics; 3/2076 subjects on brand-name drugs (OR 1.69; 95 % CI 0.40-7.20). This meta-analysis strengthens the evidence for clinical equivalence between brand-name and generic cardiovascular drugs. Physicians could be reassured about prescribing generic cardiovascular drugs, and health care organization about endorsing their wider use
Full information and full control in a behavioral context
In this paper, the concepts of full information (FI) and full control (FC), which arise in standard H∞ theory, are extended to the behavioral framework. The H∞ optimal interconnection problem formulation is outlined and the solution presented. The behavioral versions of the FI and FC problems are introduced, followed by connections with the input/output versions of the FI and FC problems and the associated Riccati equations. An illustrative example is presented
Behavioral approach to robustness analysis
This paper introduces a general and powerful framework for modeling and analysis of uncertain systems. One immediate concrete result of this work is a practical method for computing robust performance in the presence of norm-bounded perturbations and both norm-bounded and white-noise disturbances
Differences in collagen prolyl 4-hydroxylase assembly between two Caenorhabditis nematode species despite high amino acid sequence identity of the enzyme subunits
The collagen prolyl 4-hydroxylases (P4Hs) are
essential for proper extracellular matrix
formation in multicellular organisms. The
vertebrate enzymes are α2β2 tetramers, in
which the β subunits are identical to protein
disulfide isomerase (PDI). Unique P4H forms
have been shown to assemble from the
<i>Caenorhabditis</i> <i>elegans</i> catalytic α subunit
isoforms PHY-1 and PHY-2 and the β subunit
PDI-2. A mixed PHY-1/PHY-2/(PDI-2)<sub>2</sub>
tetramer is the major form, while PHY-1/PDI-
2 and PHY-2/PDI-2 dimers are also assembled
but less efficiently. Cloning and
characterization of the orthologous subunits
from the closely related nematode
<i>Caenorhabditis</i> <i>briggsae</i> revealed distinct
differences in the assembly of active P4H
forms in spite of the extremely high amino
acid sequence identity (92-97%) between the
<i>C. briggsae</i> and <i>C. elegans</i> subunits. In
addition to a PHY-1/PHY-2(PDI-2)<sub>2</sub> tetramer
and a PHY-1/PDI-2 dimer, an active (PHY-
2)<sub>2</sub>(PDI-2)<sub>2</sub> tetramer was formed in <i>C.
briggsae</i> instead of a PHY-2/PDI-2 dimer.
Site-directed mutagenesis studies and
generation of inter-species hybrid polypeptides
showed that the N-terminal halves of the
<i>Caenorhabditis</i> PHY-2 polypeptides
determine their assembly properties. Genetic
disruption of <i>C. briggsae phy-1</i> (<i>Cb-dpy-18</i>)
via a <i>Mos1</i> insertion resulted a small (short)
phenotype that is less severe than the dumpy
(short and fat) phenotype of the corresponding
<i>C. elegans</i> mutants (<i>Ce-dpy-18</i>). <i>C. briggsae</i>
<i>phy-2</i> RNA interference produced no visible
phenotype in the wild type nematodes but
produced a severe dumpy phenotype and larval
arrest in <i>phy-1</i> mutants. Genetic
complementation of the <i>C. briggsae</i> and <i>C.
elegans</i> <i>phy-1</i> mutants was achieved by
injection of a wild type <i>phy-1</i> gene from either
species
Time- and frequency-resolved fluorescence with a single TCSPC detector via a Fourier-transform approach
We introduce a broadband single-pixel spectro-temporal fluorescence detector, combining time-correlated single photon counting (TCSPC) with Fourier transform (FT) spectroscopy. A birefringent common-path interferometer (CPI) generates two time-delayed replicas of the sample's fluorescence. Via FT of their interference signal at the detector, we obtain a two-dimensional map of the fluorescence as a function of detection wavelength and emission time, with high temporal and spectral resolution. Our instrument is remarkably simple, as it only requires the addition of a CPI to a standard single-pixel TCSPC system, and it shows a readily adjustable spectral resolution with inherently broad bandwidth coverage
Type Ia Supernova Properties as a Function of the Distance to the Host Galaxy in the SDSS-II SN Survey
We use type-Ia supernovae (SNe Ia) discovered by the SDSS-II SN Survey to
search for dependencies between SN Ia properties and the projected distance to
the host galaxy center, using the distance as a proxy for local galaxy
properties (local star-formation rate, local metallicity, etc.). The sample
consists of almost 200 spectroscopically or photometrically confirmed SNe Ia at
redshifts below 0.25. The sample is split into two groups depending on the
morphology of the host galaxy. We fit light-curves using both MLCS2k2 and
SALT2, and determine color (AV, c) and light-curve shape (delta, x1) parameters
for each SN Ia, as well as its residual in the Hubble diagram. We then
correlate these parameters with both the physical and the normalized distances
to the center of the host galaxy and look for trends in the mean values and
scatters of these parameters with increasing distance. The most significant (at
the 4-sigma level) finding is that the average fitted AV from MLCS2k2 and c
from SALT2 decrease with the projected distance for SNe Ia in spiral galaxies.
We also find indications that SNe in elliptical galaxies tend to have narrower
light-curves if they explode at larger distances, although this may be due to
selection effects in our sample. We do not find strong correlations between the
residuals of the distance moduli with respect to the Hubble flow and the
galactocentric distances, which indicates a limited correlation between SN
magnitudes after standardization and local host metallicity.Comment: Accepted for publication in The Astrophysical Journal (33 pages, 5
figures, 8 tables
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