2,976 research outputs found
Quick Calculation for Sample Size while Controlling False Discovery Rate with Application to Microarray Analysis
Sample size estimation is important in microarray or proteomic experiments since biologists can typically afford only a few repetitions. In the multiple testing problems involving these experiments, it is more powerful and more reasonable to control false discovery rate (FDR) or positive FDR (pFDR) instead of type I error, e.g., family-wise error rate (FWER) (Storey and Tibshirani, 2003). However, the traditional approach of estimating sample size is no longer applicable to controlling FDR, which has left most practitioners to rely on haphazard guessing. We propose a procedure to calculate sample size while controlling false discovery rate. Two major definitions of the false discovery rate (FDR in Benjamini and Hochberg, 1995, and pFDR in Storey, 2002) vary slightly. Our procedure applies to both definitions. The proposed method is straightforward to apply and requires minimal computation, as illustrated with two sample t-tests and F-tests. We have also demonstrated by simulation that, with the calculated sample size, the desired level of power is achievable by the q-value procedure (Storey, Taylor and Siegmund, 2004) when gene expressions are either independent or dependent
Rational foundation of GR in terms of statistical mechanic in the AdS/CFT framework
In this article, we work out the microscopic statistical foundation of the
supergravity description of the simplest 1/2 BPS sector in the AdS(5)/CFT(4).
Then, all the corresponding supergravity observables are related to
thermodynamical observables, and General Relativity is understood as a
mean-field theory. In particular, and as an example, the Superstar is studied
and its thermodynamical properties clarified.Comment: 13 pages, 6 eps figures, latex, some improvements introduced,
reference added, typos correcte
An efficient compressive sensing based PS-DInSAR method for surface deformation estimation
Permanent scatterers differential interferometric synthetic aperture radar (PS-DInSAR) is a
technique for detecting surface micro-deformation, with an accuracy at the centimeter to millimeter
level. However, its performance is limited by the number of SAR images available (normally more than
20 are needed). Compressive Sensing (CS) has been proven to be an effective signal recovery method
with only a very limited number of measurements. Applying CS to PS-DInSAR, a novel
CS-PS-DInSAR method is proposed to estimate the deformation with fewer SAR images. By analyzing
the PS-DInSAR process in detail, first the sparsity representation of deformation velocity difference is
obtained; then, the mathematical model of CS-PS-DInSAR is derived and the restricted isometry
property (RIP) of the measurement matrix is discussed to validate the proposed CS-PS-DInSAR in
theory. The implementation of CS-PS-DInSAR is achieved by employing basis pursuit algorithms to
estimate the deformation velocity. With the proposed method, DInSAR deformation estimation can be
achieved by a much smaller number of SAR images, as demonstrated by simulation result
AdS pp-waves
We obtain the pp-waves of D=5 and D=4 gauged supergravities supported by
and gauge field strengths respectively. We show that
generically these solutions preserve 1/4 of the supersymmetry, but
supernumerary supersymmetry can arise for appropriately constrained harmonic
functions associated with the pp-waves. In particular it implies that the
solutions are independent of the light-cone coordinate . We also obtain
the pp-waves in the Freedman-Schwarz model.Comment: Latex, 19 pages, minor changes, to appear in JHE
An image reconstruction algorithm based on the semiparametric model for electrical capacitance tomography
AbstractElectrical capacitance tomography (ECT) is considered as a promising tomography technology, and exactly reconstructing the original objects is highly desirable in real applications. In this paper, a generalized image reconstruction model that simultaneously considers the inaccurate property in the measured capacitance data and the linearization approximation error is presented. A generalized objective function, which has been developed using a combinational M-estimation and an extended stabilizing item, is proposed. The objective function unifies six estimation methods into a concise formula, where different estimation methods can be easily obtained by selecting different parameters. The homotopy method that integrates the beneficial advantages of the alternant iteration scheme is employed to solve the proposed objective function. Numerical simulations are implemented to evaluate the numerical performances and effectiveness of the proposed algorithm, and the numerical results reveal that the proposed algorithm is efficient and overcomes the numerical instability in the process of ECT image reconstruction. For the reconstructed objects in this paper, a dramatic improvement in accuracy and spatial resolution can be achieved, which indicates that the proposed algorithm is a promising candidate for solving ECT inverse problems
Fermions from Half-BPS Supergravity
We discuss collective coordinate quantization of the half-BPS geometries of
Lin, Lunin and Maldacena (hep-th/0409174). The LLM geometries are parameterized
by a single function on a plane. We treat this function as a collective
coordinate. We arrive at the collective coordinate action as well as path
integral measure by considering D3 branes in an arbitrary LLM geometry. The
resulting functional integral is shown, using known methods (hep-th/9309028),
to be the classical limit of a functional integral for free fermions in a
harmonic oscillator. The function gets identified with the classical limit
of the Wigner phase space distribution of the fermion theory which satisfies u
* u = u. The calculation shows how configuration space of supergravity becomes
a phase space (hence noncommutative) in the half-BPS sector. Our method sheds
new light on counting supersymmetric configurations in supergravity.Comment: 28 pages, 2 figures, epsf;(v3) eq. (3.3) clarified and notationally
simplified; version to appear in JHE
Minisuperspace Quantization of "Bubbling AdS" and Free Fermion Droplets
We quantize the space of 1/2 BPS configurations of Type IIB SUGRA found by
Lin, Lunin and Maldacena (hep-th/0409174), directly in supergravity. We use the
Crnkovic-Witten-Zuckerman covariant quantization method to write down the
expression for the symplectic structure on this entire space of solutions. We
find the symplectic form explicitly around AdS_5 x S^5 and obtain a U(1)
Kac-Moody algebra, in precise agreement with the quantization of a system of N
free fermions in a harmonic oscillator potential, as expected from AdS/CFT. As
a cross check, we also perform the quantization around AdS_5 x S^5 by another
method, using the known spectrum of physical perturbations around this
background and find precise agreement with our previous calculation.Comment: 22 Pages + 2 Appendices, JHEP3; v3: explanation of factor 2 mismatch
added, references reordered, published versio
Complex Matrix Model and Fermion Phase Space for Bubbling AdS Geometries
We study a relation between droplet configurations in the bubbling AdS
geometries and a complex matrix model that describes the dynamics of a class of
chiral primary operators in dual N=4 super Yang Mills (SYM). We show rigorously
that a singlet holomorphic sector of the complex matrix model is equivalent to
a holomorphic part of two-dimensional free fermions, and establish an exact
correspondence between the singlet holomorphic sector of the complex matrix
model and one-dimensional free fermions. Based on this correspondence, we find
a relation of the singlet holomorphic operators of the complex matrix model to
the Wigner phase space distribution. By using this relation and the AdS/CFT
duality, we give a further evidence that the droplets in the bubbling AdS
geometries are identified with those in the phase space of the one-dimensional
fermions. We also show that the above correspondence actually maps the
operators of N=4 SYM corresponding to the (dual) giant gravitons to the droplet
configurations proposed in the literature.Comment: 27 pages, 6 figures, some clarification, typos corrected, published
versio
Integrated disease management of leaf spots and crown rust of oat
Non-Peer ReviewedCrown rust and leaf spots can reduce the yield and quality of oats. The objective of this research was to determine the effect of conventional fungicides, Actigard® and oat cultivars that vary in resistance to crown rust on leaf spot and crown rust severity, and oat yield and quality. Two experiments were established at each location in Saskatchewan: Saskatoon and Melfort. Experiment one consisted of three oat varieties: AC Morgan (crown rust susceptible), CDC Dancer (intermediate) and CDC Morrison (resistant) and three fungicide treatments: check (unsprayed), propiconazole and pyraclostrobin. Experiment two consisted of the application of Actigard® at two rates: 8.75 g ai/ha and 26.25 g ai/ha; three crop growth stages: seedling, boot and heading; on two varieties: CDC Dancer and CDC Morrison, with an unsprayed check for each variety. At Saskatoon, crown rust was observed while leaf spot severity was low. At Melfort, no crown rust was observed but leaf spot severity was low to moderate. Fungicide reduced the severity of crown rust and increased yield and quality of oat at Saskatoon for the susceptible variety (AC Morgan) and somewhat for the moderately susceptible variety (CDC Dancer). The crown rust resistant variety (CDC Morrison) did not benefit from fungicide. Leaf spots were reduced by fungicide application at Melfort, but little increase in yield or quality was detected. There was little difference between AC Morgan and CDC Morrison for leaf spot symptoms, but CDC Dancer appeared to suffer slightly more than the other varieties. There was no impact of fungicide on beta-glucan content at either location, although there were differences among varieties, but only at Saskatoon. Actigard® was not observed to have any positive or negative effects on disease severity (crown rust or leaf spots) or any of the factors measured, including nutritional characteristics, at either location, although there were differences among varieties for many of the factors measured
Generating Neutrino Mass in the 331 Model
A mechanism for generating small tree-level Majorana mass for neutrinos is
implemented in the 331 Model. No additional fermions or scalars need to be
added, and no mass scale greater than a few TeV is invoked.Comment: LaTex, 7 pages, no figures. Revised version to appear in Phys. Rev.
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