1,058 research outputs found
Correction: Calderon, C.P. Data-Driven Techniques for Detecting Dynamical State Changes in Noisily Measured 3D Single-Molecule Trajectories. Molecules 19, 18381-18398
No full textThe author wishes to make the following corrections to paper [1] (doi:10.3390/molecules191118381, website: http://www.mdpi.com/1420-3049/19/11/18381)
The L-p-to-L-q boundedness of commutators with applications to the Jacobian operator
No full textSupplying the missing necessary conditions, we complete the characterisation of the L-p -> L-q boundedness of commutators [b, T] of pointwise multiplication and Calderon-Zygmund operators, for arbitrary pairs of 1 q, our results are new even for special classical operators with smooth kernels. As an application, we show that every f is an element of L-p(R-d) can be represented as a convergent series of normalised Jacobians J(u) = det del uof u is an element of (over dot(W))(1,dp)(R-d)(d). This extends, from p = 1 to p > 1, a result of Coifman, Lions, Meyer and Semmes about J:. (over dot(W))(1,d)(R-d)(d) -> H-1(R-d), and supports a conjecture of Iwaniec about the solvability of the equation Ju = f is an element of L-p(R-d). (C) 2021 The Author(s). Published by Elsevier Masson SAS.Peer reviewe
Data-Driven Techniques for Detecting Dynamical State Changes in Noisily Measured 3D Single-Molecule Trajectories
No full textOptical microscopes and nanoscale probes (AFM, optical tweezers, etc.) afford researchers tools capable of quantitatively exploring how molecules interact with one another in live cells. The analysis of in vivo single-molecule experimental data faces numerous challenges due to the complex, crowded, and time changing environments associated with live cells. Fluctuations and spatially varying systematic forces experienced by molecules change over time; these changes are obscured by “measurement noise” introduced by the experimental probe monitoring the system. In this article, we demonstrate how the Hierarchical Dirichlet Process Switching Linear Dynamical System (HDP-SLDS) of Fox et al. [IEEE Transactions on Signal Processing 59] can be used to detect both subtle and abrupt state changes in time series containing “thermal” and “measurement” noise. The approach accounts for temporal dependencies induced by random and “systematic overdamped” forces. The technique does not require one to subjectively select the number of “hidden states” underlying a trajectory in an a priori fashion. The number of hidden states is simultaneously inferred along with change points and parameters characterizing molecular motion in a data-driven fashion. We use large scale simulations to study and compare the new approach to state-of-the-art Hidden Markov Modeling techniques. Simulations mimicking single particle tracking (SPT) experiments are the focus of this study
Price caps, efficiency payoffs, and infrastructure contract renegotiation in Latin America
No full textTwenty years ago, as the United Kingdom was getting ready to launch the privatization of its public services, Professor Littlechild developed and operationalized the concept of price caps as a regulatory regime to control for residual monopoly conditions in those services. Ten years later, Latin American countries, as they embarked into their own infrastructure reforms, also adopted the price cap regulatory model. Relying on a large data base on the factors driving contract renegotiation in the region and a survey of the literature on efficiency gains, the authors assess the impact of this regulatory regime in Latin America. They show that while the expected efficiency gains were amply achieved, these gains were seldom passed on to the users. Instead they were shared by the government and the firms. Moreover, the adoption of price caps implied higher costs of capital and hence, tariffs, and brought down levels of investment.International Terrorism&Counterterrorism,Decentralization,Labor Policies,Banks&Banking Reform,Environmental Economics&Policies,Banks&Banking Reform,Environmental Economics&Policies,International Terrorism&Counterterrorism,Water Supply and Sanitation Participation,Community Participation in Water Supply and Sanitation
GRADIENT ESTIMATES FOR THE STRONG p(x)-LAPLACE EQUATION
No full textWe study nonlinear elliptic equations of strong p (x)-Laplacian type to obtain an interior Calderon-Zygmund type estimates by finding a correct regularity assumption on the variable exponent p (x). Our proof is based on the maximal function technique and the appropriate localization method.NSFC [11671111, 11601103, 11571020]; Natural Science Foundation of Heilongjiang Province [QC2014C002]; Heilongjiang Province Postdoctoral Special Science Foundation [LBHTZ0514]SCI(E)ARTICLE74109-41293
Tuning the Oxygen Reduction Activity and Stability of Catalysts through Controlling Pt Surface Composition, Strain, and Electronic Structure
No full textNanoparticles of Ni(OH) surrounded with ultra-low Pt content and supported on functionalized carbon were prepared by a scalable synthesis method and investigated as electrocatalysts for the oxygen reduction reaction (ORR) in acidic media. The effect of altering the Pt surface composition on the Ni(OH) nanoparticle core was investigated as a route to simultaneously increase the ORR activity and stability. Modifying the Pt surface composition resulted in both structural and electronic changes. Decreasing the Pt surface composition resulted in stronger Pt-Pt compressive strain and decrease in the occupancy of d-band vacancies per atom. The correlation of strain and d-vacancies with ORR activity and stability showed a Volcano-type tendency, with the 6 wt. % Pt sample showing the highest activity and stability. The electrochemical results obtained using rotating disk electrode (RDE) tests showed an enhancement of about six times higher surface and mass-normalized activity as well as improved durability compared to commercial Pt/C. These improvements were further corroborated by single cell membrane electrode assembly (MEA) tests where similar trends were observed, showing higher power densities with lower Pt loadings, in comparison with commercial Pt/C. These results show that new electrocatalysts with higher activity and stability can be obtained through precise control of the atomic-level catalyst structure
The association between adverse childhood experiences and chronic morbidity in adulthood: Does level of education moderate?
No full text[ABSTRACT ONLY; NO FULL TEXT] Background: Adverse Childhood Experiences (ACEs) such as physical abuse, parental mental illness, and substance misuse, have the potential to impact health negatively in adulthood. This study investigated the relationship between ACE exposure (low, moderate, high) and chronic morbidity. Specifically, if high exposure increases the odds for multiple morbidities in adults. This secondary analysis will also examine the moderating effect education has on this relationship. Methods: Survey data from the adult 2022 California Health Interview Survey (CHIS) (N=21,463), a cross-sectional study that explores health-related questions, including ACEs and morbidity, was utilized. An ordinal logistic regression assessed the relationship between ACE exposure and chronic multimorbidity. A second ordinal model with an interaction term, measured whether education moderated the relationship between ACE exposure and multiple morbidity. All models adjusted for sex, race, education, total annual household income, age, and marital status. Results: Adults with high (AOR: 1.17, 95%CI: [1.09, 1.26], p=0.001) and moderate ACE exposure (AOR: 1.07, 95%CI: [1.00, 1.14], p=0.001) had higher odds of having multimorbidities compared to adults with low exposure. Level of education did not moderate the relationship between ACE exposure and multimorbidity (p>0.05). Conclusion: Moderate and high ACE exposure was associated with adults reporting multimorbidities. These findings add to the existing literature regarding this relationship. However, education did not offset the relationship between ACE exposure and having multimorbidities. This analysis still highlights the importance of continued research in ACE-exposed adults to support with tailoring morbidity prevention and intervention programs for this population and the protective factor of education
P-Splines Using Derivative Information
No full textTime series associated with single-molecule experiments and/or simulations contain a wealth of multiscale information about complex biochemical systems. However efficiently extracting and representing useful physical information from these time series measurements can be challenging. We demonstrate how Penalized splines (P-Splines) can be useful in summarizing complex single-molecule time series data using quantities estimated from the observed data. A design matrix that simultaneously uses noisy function and derivative scatterplot information to refine function estimates using P-spline techniques is introduced. The approach is called the PuDI (P-Splines using Derivative Information) method. We show how Generalized Least Squares fits seamlessly into the PuDI method; several applications demonstrating how inclusion of uncertainty information improves the PuDI function estimates are presented. The PuDI design matrix can be used to assist scatterplot smoothing applications where both unbiased function and derivative estimates are available
A GFP tagged 2D chromatid trajectory exhibiting rapid two state regime switching.
No full text<p>The vertical red lines denote the change points identified by the HDP-SLDS analysis.</p
Identification of autophosphorylation sites in eukaryotic elongation factor-2 kinase
No full texteEF2K [eEF2 (eukaryotic elongation factor 2) kinase] phosphorylates and inactivates the translation elongation factor eEF2. eEF2K is not a member of the main eukaryotic protein kinase superfamily, but instead belongs to a small group of so-called ?-kinases. The activity of eEF2K is normally dependent upon Ca2+ and calmodulin. eEF2K has previously been shown to undergo autophosphorylation, the stoichiometry of which suggested the existence of multiple sites. In the present study we have identified several autophosphorylation sites, including Thr348, Thr353, Ser366 and Ser445, all of which are highly conserved among vertebrate eEF2Ks. We also identified a number of other sites, including Ser78, a known site of phosphorylation, and others, some of which are less well conserved. None of the sites lies in the catalytic domain, but three affect eEF2K activity. Mutation of Ser78, Thr348 and Ser366 to a non-phosphorylatable alanine residue decreased eEF2K activity. Phosphorylation of Thr348 was detected by immunoblotting after transfecting wild-type eEF2K into HEK (human embryonic kidney)-293 cells, but not after transfection with a kinase-inactive construct, confirming that this is indeed a site of autophosphorylation. Thr348 appears to be constitutively autophosphorylated in vitro. Interestingly, other recent data suggest that the corresponding residue in other ?-kinases is also autophosphorylated and contributes to the activation of these enzymes [Crawley, Gharaei, Ye, Yang, Raveh, London, Schueler-Furman, Jia and Cote (2011) J. Biol. Chem. 286, 2607-2616]. Ser366 phosphorylation was also detected in intact cells, but was still observed in the kinase-inactive construct, demonstrating that this site is phosphorylated not only autocatalytically but also in trans by other kinases
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