623 research outputs found
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Estimability and efficiency in nearly orthogonal 2[m1] x 3[m2] deletion designs
This article considers single replicate factorial experiments in incomplete blocks. A single replicate 2^m1 x 3^m2 deletion design in 3 incomplete blocks is obtained from a single replicate 3^m, where m = m_1 + m_2, preliminary design by deleting all runs (or treatment combinations) with the first m_1 factors at the level two. A systematic method for determining the unbiasedly estimable (u.e.) and not unbiasedly estimable (n.u.e.) factorial effects is provided. It is shown that for m_2 > 0 all factorial effects of the type F( α_1 · · · α_m_1 , α_(m_1 +1) · · · α_m), where α_i; = 0, l for i = 1, · · ·, m_1, α_i; = 0, 1, 2 for i = m_(1+1), · · ·, m, with (α_1 · · · α_m) != (0 · · · 0), and (α_m,+l · · · _m) != α(l · · · 1) for a= 1, 2, are u.e. and the remaining factorial effects are n.u.e. It is noted that (2^m_1 - 1) factorial effects of 2^m_1 factorial experiments and (3^m_2) factorial effects of 3^m, factorial experiments, which are embedded in 2^m_1 x 3^m, factorial experiments, are u. e. The 2 x 3m-l deletion designs were considered in the work of Voss (1986). Defining factorial effects of a 2^m_1 x 3^m, factorial experiment in a form different than in Voss (1986), we develop a simple representation of u.e. and n. u. e. factorial effects. In this representation, there are (2^(m_1 + 1) + 1) n. u. e. factorial effects of the type F( α_1 · · · α_m_1, α· · · α). This number is smaller than the corresponding number of n. u. e. factorial effects in the representation of Voss (1986). The relative efficiency expressions, and their bounds, in the estimation of factorial effects of 2^m_1 x 3^m_2 deletion designs are also given
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Measuring ligand efficacy at the mu-opioid receptor using a conformational biosensor.
The intrinsic efficacy of orthosteric ligands acting at G-protein-coupled receptors (GPCRs) reflects their ability to stabilize active receptor states (R*) and is a major determinant of their physiological effects. Here, we present a direct way to quantify the efficacy of ligands by measuring the binding of a R*-specific biosensor to purified receptor employing interferometry. As an example, we use the mu-opioid receptor (µ-OR), a prototypic class A GPCR, and its active state sensor, nanobody-39 (Nb39). We demonstrate that ligands vary in their ability to recruit Nb39 to µ-OR and describe methadone, loperamide, and PZM21 as ligands that support unique R* conformation(s) of µ-OR. We further show that positive allosteric modulators of µ-OR promote formation of R* in addition to enhancing promotion by orthosteric agonists. Finally, we demonstrate that the technique can be utilized with heterotrimeric G protein. The method is cell-free, signal transduction-independent and is generally applicable to GPCRs
Time's Barbed Arrow: Irreversibility, Crypticity, and Stored Information
We show why the amount of information communicated between the past and
future--the excess entropy--is not in general the amount of information stored
in the present--the statistical complexity. This is a puzzle, and a
long-standing one, since the latter is what is required for optimal prediction,
but the former describes observed behavior. We layout a classification scheme
for dynamical systems and stochastic processes that determines when these two
quantities are the same or different. We do this by developing closed-form
expressions for the excess entropy in terms of optimal causal predictors and
retrodictors--the epsilon-machines of computational mechanics. A process's
causal irreversibility and crypticity are key determining properties.Comment: 4 pages, 2 figure
Discussion of boundary-layer characteristics near the casing of an axial-flow compressor
Boundary-layer velocity profiles on the casing of an axial-flow compressor behind the guide vanes and rotor were measured and resolved into two components: along the streamline of the flow and perpendicular to it. Boundary-layer thickness and the deflection of the boundary layer at the wall were the generalizing parameters. By use of these results and the momentum-integral equations, the characteristics of boundary on the walls of axial-flow compressor are qualitatively discussed. Important parameters concerning secondary flow in the boundary layer appear to be turning of the flow and the product of boundary-layer thickness and streamline curvature outside the boundary layer. Two types of separation are shown to be possible in three dimensional boundary layer
Recent Decisions
Comments on recent decisions by Robert E. Sullivan, James H. Graham, John E. Savord, Edward A. Mahoney, Jr., and Ronald P. Rejent
Contributor to the November Issue/Notes
Notes by Charles G. Hasson, Robert J. Mahoney, Robert E. Sullivan, John Kelly, John D. O\u27Neill, John M. Anderton, Charles R. Gerard, R. A. Macdonell, William B. Ball, Robert E. Sullivan, and Leonard D. Bodkin
Contributor to the November Issue/Notes
Notes by Charles G. Hasson, Robert J. Mahoney, Robert E. Sullivan, John Kelly, John D. O\u27Neill, John M. Anderton, Charles R. Gerard, R. A. Macdonell, William B. Ball, Robert E. Sullivan, and Leonard D. Bodkin
Comparison of Sub-Scalp EEG and Endovascular Stent-Electrode Array for Visually Evoked Potential Brain-Computer Interface
Brain-computer interfaces (BCI) have the potential to improve the quality of
life for persons with paralysis. Sub-scalp EEG provides an alternative BCI
signal acquisition method that compromises between the limitations of
traditional EEG systems and the risks associated with intracranial electrodes,
and has shown promise in long-term seizure monitoring. However, sub-scalp EEG
has not yet been assessed for suitability in BCI applications. This study
presents a preliminary comparison of visually-evoked potentials (VEPs) recorded
using subscalp and endovascular stent electrodes in a sheep. Sub-scalp
electrodes recorded comparable VEP amplitude, signal-to-noise ratio and
bandwidth to the stent electrodes.Comment: 4 pages, 5 figures, EMBC 2023 submissio
Synchronization and Control in Intrinsic and Designed Computation: An Information-Theoretic Analysis of Competing Models of Stochastic Computation
We adapt tools from information theory to analyze how an observer comes to
synchronize with the hidden states of a finitary, stationary stochastic
process. We show that synchronization is determined by both the process's
internal organization and by an observer's model of it. We analyze these
components using the convergence of state-block and block-state entropies,
comparing them to the previously known convergence properties of the Shannon
block entropy. Along the way, we introduce a hierarchy of information
quantifiers as derivatives and integrals of these entropies, which parallels a
similar hierarchy introduced for block entropy. We also draw out the duality
between synchronization properties and a process's controllability. The tools
lead to a new classification of a process's alternative representations in
terms of minimality, synchronizability, and unifilarity.Comment: 25 pages, 13 figures, 1 tabl
Investigation of Blade-row Flow Distributions in Axial-flow-compressor Stage Consisting of Guide Vanes and Rotor-blade Row
A 30-inch tip-diameter axial-flow compressor stage was investigated with and without rotor to determine individual blade-row performance, interblade-row effects, and outer-wall boundary-layer conditions. Velocity gradients at guide-vane outlet without rotor approximated design assumptions, when the measured variation of leaving angle was considered. With rotor in operation, Mach number and rotor-blade effects changed flow distribution leaving guide vanes and invalidated design assumption of radial equilibrium. Rotor-blade performance correlated interpolated two-dimensional results within 2 degrees, although tip stall was indicated in experimental and not two-dimensional results. Boundary-displacement thickness was less than 1.0 and 1.5 percent of passage height after guide vanes and after rotor, respectively, but increased rapidly after rotor when tip stall occurred
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