Preconditioners for Wiener--Hopf Equations with High-Order Quadrature Rules

We consider solving the Wiener--Hopf equations with high-order quadrature rules by preconditioned conjugate gradient (PCG) methods. We propose using convolution operators as preconditioners for these equations. We will show that with the proper choice of kernel functions for the preconditioners, the resulting preconditioned equations will have clustered spectra and therefore can be solved by the PCG method with superlinear convergence rate. Moreover, the discretization of these equations by high-order quadrature rules leads to matrix systems that involve only Toeplitz or diagonal matrix--vector multiplications and hence can be computed efficiently by FFTs. Numerical results are given to illustrate the fast convergence of the method and the improvement on accuracy by using higher-order quadrature rule. We also compare the performance of our preconditioners with the circulant integral operators.published_or_final_versio

Relationship between the molecular composition, visible light absorption, and health-related properties of smoldering woodsmoke aerosols

Organic aerosols generated from the smoldering combustion of wood critically impact air quality and health for billions of people worldwide; yet, the links between the chemical components and the optical or biological effects of woodsmoke aerosol (WSA) are still poorly understood. In this work, an untargeted analysis of the molecular composition of smoldering WSA, generated in a controlled environment from nine types of heartwood fuels (African mahogany, birch, cherry, maple, pine, poplar, red oak, redwood, and walnut), identified several hundred compounds using gas chromatography mass spectrometry (GCMS) and nano-electrospray high-resolution mass spectrometry (HRMS) with tandem multistage mass spectrometry (MSn). The effects of WSA on cell toxicity as well as gene expression dependent on the aryl hydrocarbon receptor (AhR) and estrogen receptor (ER) were characterized with cellular assays, and the visible mass absorption coefficients (MACvis) of WSA were measured with ultraviolet-visible spectroscopy. The WSAs studied in this work have significant levels of biological and toxicological activity, with exposure levels in both an outdoor and indoor environment similar to or greater than those of other toxicants. A correlation between the HRMS molecular composition and aerosol properties found that phenolic compounds from the oxidative decomposition of lignin are the main drivers of aerosol effects, while the cellulose decomposition products play a secondary role; e.g., levoglucosan is anticorrelated with multiple effects. Polycyclic aromatic hydrocarbons (PAHs) are not expected to form at the combustion temperature in this work, nor were they observed above the detection limit; thus, biological and optical properties of the smoldering WSA are not attributed to PAHs. Syringyl compounds tend to correlate with cell toxicity, while the more conjugated molecules (including several compounds assigned to dimers) have higher AhR activity and MACvis. The negative correlation between cell toxicity and AhR activity suggests that the toxicity of smoldering WSA to cells is not mediated by the AhR. Both mass-normalized biological outcomes have a statistically significant dependence on the degree of combustion of the wood. In addition, our observations support the fact that the visible light absorption of WSA is at least partially due to charge transfer effects in aerosols, as previously suggested. Finally, MACvis has no correlation with toxicity or receptor signaling, suggesting that key chromophores in this work are not biologically active on the endpoints tested

Construction and Control of Genetic Regulatory Networks: A Multivariate Markov Chain Approach

In the post-genomic era, the construction and control of genetic regulatory networks using gene expression data is a hot research topic. Boolean networks (BNs) and its extension Probabilistic Boolean Networks (PBNs) have been served as an effective tool for this purpose. However, PBNs are difficult to be used in practice when the number of genes is large because of the huge computational cost. In this paper, we propose a simplified multivariate Markov model for approximating a PBN The new model can preserve the strength of PBNs, the ability to capture the inter-dependence of the genes in the network, qnd at the same time reduce the complexity of the network and therefore the computational cost. We then present an optimal control model with hard constraints for the purpose of control/intervention of a genetic regulatory network. Numerical experimental examples based on the yeast data are given to demonstrate the effectiveness of our proposed model and control policy.published_or_final_versio

smt: a Matlab structured matrices toolbox

We introduce the smt toolbox for Matlab. It implements optimized storage and fast arithmetics for circulant and Toeplitz matrices, and is intended to be transparent to the user and easily extensible. It also provides a set of test matrices, computation of circulant preconditioners, and two fast algorithms for Toeplitz linear systems.Comment: 19 pages, 1 figure, 1 typo corrected in the abstrac

C-type natriuretic peptide is a pivotal regulator of metabolic homeostasis

Thermogenesis and adipogenesis are tightly regulated mechanisms that maintain lipid homeostasis and energy balance; dysfunction of these critical processes underpins obesity and contributes to cardiometabolic disease. C-type natriuretic peptide (CNP) fulfills a multimodal protective role in the cardiovascular system governing local blood flow, angiogenesis, cardiac function, and immune cell reactivity. Herein, we investigated a parallel, preservative function for CNP in coordinating metabolic homeostasis. Global inducible CNP knockout mice exhibited reduced body weight, higher temperature, lower adiposity, and greater energy expenditure in vivo. This thermogenic phenotype was associated with increased expression of uncoupling protein-1 and preferential lipid utilization by mitochondria, a switch corroborated by a corresponding diminution of insulin secretion and glucose clearance. Complementary studies in isolated murine and human adipocytes revealed that CNP exerts these metabolic regulatory actions by inhibiting sympathetic thermogenic programming via G(i)-coupled natriuretic peptide receptor (NPR)-C and reducing peroxisome proliferator-activated receptor-γ coactivator-1α expression, while concomitantly driving adipogenesis via NPR-B/protein kinase-G. Finally, we identified an association between CNP/NPR-C expression and obesity in patient samples. These findings establish a pivotal physiological role for CNP as a metabolic switch to balance energy homeostasis. Pharmacological targeting of these receptors may offer therapeutic utility in the metabolic syndrome and related cardiovascular disorders

Performance optimization of a leagility inspired supply chain model: a CFGTSA algorithm based approach

Lean and agile principles have attracted considerable interest in the past few decades. Industrial sectors throughout the world are upgrading to these principles to enhance their performance, since they have been proven to be efficient in handling supply chains. However, the present market trend demands a more robust strategy incorporating the salient features of both lean and agile principles. Inspired by these, the leagility principle has emerged, encapsulating both lean and agile features. The present work proposes a leagile supply chain based model for manufacturing industries. The paper emphasizes the various aspects of leagile supply chain modeling and implementation and proposes a new Hybrid Chaos-based Fast Genetic Tabu Simulated Annealing (CFGTSA) algorithm to solve the complex scheduling problem prevailing in the leagile environment. The proposed CFGTSA algorithm is compared with the GA, SA, TS and Hybrid Tabu SA algorithms to demonstrate its efficacy in handling complex scheduling problems

The relevance of outsourcing and leagile strategies in performance optimization of an integrated process planning and scheduling

Over the past few years growing global competition has forced the manufacturing industries to upgrade their old production strategies with the modern day approaches. As a result, recent interest has been developed towards finding an appropriate policy that could enable them to compete with others, and facilitate them to emerge as a market winner. Keeping in mind the abovementioned facts, in this paper the authors have proposed an integrated process planning and scheduling model inheriting the salient features of outsourcing, and leagile principles to compete in the existing market scenario. The paper also proposes a model based on leagile principles, where the integrated planning management has been practiced. In the present work a scheduling problem has been considered and overall minimization of makespan has been aimed. The paper shows the relevance of both the strategies in performance enhancement of the industries, in terms of their reduced makespan. The authors have also proposed a new hybrid Enhanced Swift Converging Simulated Annealing (ESCSA) algorithm, to solve the complex real-time scheduling problems. The proposed algorithm inherits the prominent features of the Genetic Algorithm (GA), Simulated Annealing (SA), and the Fuzzy Logic Controller (FLC). The ESCSA algorithm reduces the makespan significantly in less computational time and number of iterations. The efficacy of the proposed algorithm has been shown by comparing the results with GA, SA, Tabu, and hybrid Tabu-SA optimization methods

Atomic physics: An almost lightless laser

Lasers are often described in terms of a light field circulating in an optical resonator system. Now a laser has been demonstrated in which the field resides primarily in the atomic medium that is used to generate the light

A picogram and nanometer scale photonic crystal opto-mechanical cavity

We describe the design, fabrication, and measurement of a cavity opto-mechanical system consisting of two nanobeams of silicon nitride in the near-field of each other, forming a so-called "zipper" cavity. A photonic crystal patterning is applied to the nanobeams to localize optical and mechanical energy to the same cubic-micron-scale volume. The picrogram-scale mass of the structure, along with the strong per-photon optical gradient force, results in a giant optical spring effect. In addition, a novel damping regime is explored in which the small heat capacity of the zipper cavity results in blue-detuned opto-mechanical damping.Comment: 15 pages, 4 figure

Development and Validation of the Behavioral Tendencies Questionnaire

At a fundamental level, taxonomy of behavior and behavioral tendencies can be described in terms of approach, avoid, or equivocate (i.e., neither approach nor avoid). While there are numerous theories of personality, temperament, and character, few seem to take advantage of parsimonious taxonomy. The present study sought to implement this taxonomy by creating a questionnaire based on a categorization of behavioral temperaments/tendencies first identified in Buddhist accounts over fifteen hundred years ago. Items were developed using historical and contemporary texts of the behavioral temperaments, described as “Greedy/Faithful”, “Aversive/Discerning”, and “Deluded/Speculative”. To both maintain this categorical typology and benefit from the advantageous properties of forced-choice response format (e.g., reduction of response biases), binary pairwise preferences for items were modeled using Latent Class Analysis (LCA). One sample (n1 = 394) was used to estimate the item parameters, and the second sample (n2 = 504) was used to classify the participants using the established parameters and cross-validate the classification against multiple other measures. The cross-validated measure exhibited good nomothetic span (construct-consistent relationships with related measures) that seemed to corroborate the ideas present in the original Buddhist source documents. The final 13-block questionnaire created from the best performing items (the Behavioral Tendencies Questionnaire or BTQ) is a psychometrically valid questionnaire that is historically consistent, based in behavioral tendencies, and promises practical and clinical utility particularly in settings that teach and study meditation practices such as Mindfulness Based Stress Reduction (MBSR)