keyword
MENU ▼
Read by QxMD icon Read
search

Nonlinear

keyword
https://www.readbyqxmd.com/read/28215052/predicting-pregnancy-outcomes-using-longitudinal-information-a-penalized-splines-mixed-effects-model-approach
#1
Rolando De la Cruz, Claudio Fuentes, Cristian Meza, Dae-Jin Lee, Ana Arribas-Gil
We propose a semiparametric nonlinear mixed-effects model (SNMM) using penalized splines to classify longitudinal data and improve the prediction of a binary outcome. The work is motivated by a study in which different hormone levels were measured during the early stages of pregnancy, and the challenge is using this information to predict normal versus abnormal pregnancy outcomes. The aim of this paper is to compare models and estimation strategies on the basis of alternative formulations of SNMMs depending on the characteristics of the data set under consideration...
February 19, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28215045/a-generalized-partially-linear-mean-covariance-regression-model-for-longitudinal-proportional-data-with-applications-to-the-analysis-of-quality-of-life-data-from-cancer-clinical-trials
#2
Xueying Zheng, Guoyou Qin, Dongsheng Tu
Motivated by the analysis of quality of life data from a clinical trial on early breast cancer, we propose in this paper a generalized partially linear mean-covariance regression model for longitudinal proportional data, which are bounded in a closed interval. Cholesky decomposition of the covariance matrix for within-subject responses and generalized estimation equations are used to estimate unknown parameters and the nonlinear function in the model. Simulation studies are performed to evaluate the performance of the proposed estimation procedures...
February 19, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28215003/improved-electromagnetic-tracking-for-catheter-path-reconstruction-with-application-in-high-dose-rate-brachytherapy
#3
Elodie Lugez, Hossein Sadjadi, Chandra P Joshi, Selim G Akl, Gabor Fichtinger
PURPOSE: Electromagnetic (EM) catheter tracking has recently been introduced in order to enable prompt and uncomplicated reconstruction of catheter paths in various clinical interventions. However, EM tracking is prone to measurement errors which can compromise the outcome of the procedure. Minimizing catheter tracking errors is therefore paramount to improve the path reconstruction accuracy. METHODS: An extended Kalman filter (EKF) was employed to combine the nonlinear kinematic model of an EM sensor inside the catheter, with both its position and orientation measurements...
February 18, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28214528/adaptive-independent-vector-analysis-for-multi-subject-complex-valued-fmri-data
#4
Li-Dan Kuang, Qiu-Hua Lin, Xiao-Feng Gong, Fengyu Cong, Vince D Calhoun
BACKGROUND: Complex-valued fMRI data can provide additional insights beyond magnitude-only data. However, independent vector analysis (IVA), which has exhibited great potential for group analysis of magnitude-only fMRI data, has rarely been applied to complex-valued fMRI data. The main challenges in this application include the extremely noisy nature and large variability of the source component vector (SCV) distribution. NEW METHOD: To address these challenges, we propose an adaptive fixed-point IVA algorithm for analyzing multiple-subject complex-valued fMRI data...
February 15, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28214480/nonlinear-actin-deformations-lead-to-network-stiffening-yielding-and-nonuniform-stress-propagation
#5
Bekele Gurmessa, Shea Ricketts, Rae M Robertson-Anderson
We use optical tweezers microrheology and fluorescence microscopy to apply nonlinear microscale strains to entangled and cross-linked actin networks, and measure the resulting stress and actin filament deformations. We couple nonlinear stress response and relaxation to the velocities and displacements of individual fluorescent-labeled actin segments, at varying times throughout the strain and varying distances from the strain path, to determine the underlying molecular dynamics that give rise to the debated nonlinear response and stress propagation of cross-linked and entangled actin networks at the microscale...
February 15, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28213759/convection-of-a-colloidal-suspension-in-a-hele-shaw-cell
#6
B L Smorodin, I N Cherepanov, S N Ishutov, B I Myznikova
The results of a theoretical study are presented dealing with convective heat and mass transfer in a colloidal suspension through a Hele-Shaw cell heated from below. The numerical analysis, based on a multi-component model, reveals that for a certain range of parameter values the dynamical regimes of travelling waves as well as oscillatory fingering formation are stable. The bifurcation phenomena and nonlinear evolution of spatiotemporal patterns that develop in the colloid suspension are modeled and discussed, paying special attention to the combined effects of gravity sedimentation, thermal diffusion with positive separation ratio and convection...
February 2017: European Physical Journal. E, Soft Matter
https://www.readbyqxmd.com/read/28213715/the-influence-of-sc-doping-on-structural-electronic-and-optical-properties-of-be12o12-mg12o12-and-ca12o12-nanocages-a-dft-study
#7
Masoomeh Omidi, Hamid Reza Shamlouei, Motahareh Noormohammadbeigi
Density functional theory (DFT) calculations were used to study the effect of scandium doping on the structural, energetic, electronic, linear and nonlinear optical (NLO) properties of Be12O12, Mg12O12 and Ca12O12 nanoclusters. Scandium (Sc) doping on nanoclusters leads to narrowing of their E g, which enhances their conductance greatly. Also, the polarizability (α) and first hyperpolarizability (β0) of nanoclusters were dramatically increased as Be, Mg or Ca atoms are substituted with a Sc atom. Among all clusters, α and β0 values for Sc-doped Ca12O12 were the largest...
March 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28213388/effects-of-dopamine-donor-pretreatment-on-graft-survival-after-kidney-transplantation-a-randomized-trial
#8
Peter Schnuelle, Wilhelm H Schmitt, Christel Weiss, Antje Habicht, Lutz Renders, Martin Zeier, Felix Drüschler, Katharina Heller, Przemyslaw Pisarski, Bernhard Banas, Bernhard K Krämer, Matthias Jung, Kai Lopau, Christoph J Olbricht, Horst Weihprecht, Peter Schenker, Johan W De Fijter, Benito A Yard, Urs Benck
BACKGROUND AND OBJECTIVES: Donor dopamine improves initial graft function after kidney transplantation due to antioxidant properties. We investigated if a 4 µg/kg per minute continuous dopamine infusion administered after brain-death confirmation affects long-term graft survival and examined the exposure-response relationship with treatment duration. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Five-year follow-up of 487 renal transplant patients from 60 European centers who had participated in the randomized, multicenter trial of dopamine donor pretreatment between 2004 and 2007 (ClinicalTrials...
February 17, 2017: Clinical Journal of the American Society of Nephrology: CJASN
https://www.readbyqxmd.com/read/28213166/influence-of-clamping-stress-and-duration-on-the-trauma-of-liver-tissue-during-surgery-operation
#9
Jin Wang, Qing-Yuan Yu, Wei Li, Bing-Rui Wang, Zhong-Rong Zhou
BACKGROUND: Tissue grasping damage often occurs in minimally invasive surgery, which would increase the postoperative recovery time and the risk of surgical complications. The purpose of this study was to evaluate the relationship between liver tissue trauma and compression stress magnitude and duration during tissue clamping operation. METHODS: The clamping experiments of liver tissues in vivo were conducted by using a universal soft tissue mechanical testing machine under different clamping stress magnitudes and durations...
February 10, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/28213120/a-cross-validated-cytoarchitectonic-atlas-of-the-human-ventral-visual-stream
#10
M Rosenke, K S Weiner, M A Barnett, K Zilles, K Amunts, R Goebel, K Grill-Spector
The human ventral visual stream consists of several areas considered processing stages essential for perception and recognition. A fundamental microanatomical feature differentiating areas is cytoarchitecture, which refers to the distribution, size, and density of cells across cortical layers. Because cytoarchitectonic structure is measured in 20-micron-thick histological slices of postmortem tissue, it is difficult to assess (a) how anatomically consistent these areas are across brains and (b) how they relate to brain parcellations obtained with prevalent neuroimaging methods, acquired at the millimeter and centimeter scale...
February 14, 2017: NeuroImage
https://www.readbyqxmd.com/read/28213092/prediction-of-thyroid-c-cell-carcinogenicity-after-chronic-administration-of-glp1-r-agonists-in-rodents
#11
Willem van den Brink, Annette Emerenciana, Francesco Bellanti, Oscar Della Pasqua, Jan Willem van der Laan
Increased incidence of C-cell carcinogenicity has been observed for glucagon-like-protein-1 receptor (GLP-1r) agonists in rodents. It is suggested that the duration of exposure is an indicator of carcinogenic potential in rodents of the different products on the market. Furthermore, the role of GLP-1-related mechanisms in the induction of C-cell carcinogenicity has gained increased attention by regulatory agencies. This study proposes an integrative pharmacokinetic/pharmacodynamic (PKPD) framework to identify explanatory factors and characterize differences in carcinogenic potential of the GLP-1r agonist products...
February 14, 2017: Toxicology and Applied Pharmacology
https://www.readbyqxmd.com/read/28212883/nonlinear-relationship-between-extreme-temperature-and-mortality-in-different-temperature-zones-a-systematic-study-of-122-communities-across-the-mainland-of-china
#12
Chenzhi Wang, Zhao Zhang, Maigeng Zhou, Lingyan Zhang, Peng Yin, Wan Ye, Yi Chen
BACKGROUND: Numerous previous studies have reported that human health risk is extremely sensitive to temperature. Very few studies, however, have characterized the relationship between temperature and mortality in different temperature zones due to the previous conclusions deduced from a regional or administrative division. A research covers different temperature zones was indispensable to have a comprehensive understanding of regional ambient temperature effect on public health. METHODS: Based on the mortality dataset and meteorological variables of 122 communities in China from 2007 to 2012, a distributed lag nonlinear model (DLNM) was utilized to estimate the temperature effect on non-accidental mortality at the community level...
February 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28212281/energy-based-acoustic-source-localization-methods-a-survey
#13
Wei Meng, Wendong Xiao
Energy-based source localization is an important problem in wireless sensor networks (WSNs), which has been studied actively in the literature. Numerous localization algorithms, e.g., maximum likelihood estimation (MLE) and nonlinear-least-squares (NLS) methods, have been reported. In the literature, there are relevant review papers for localization in WSNs, e.g., for distance-based localization. However, not much work related to energy-based source localization is covered in the existing review papers. Energy-based methods are proposed and specially designed for a WSN due to its limited sensor capabilities...
February 15, 2017: Sensors
https://www.readbyqxmd.com/read/28212112/cancer-as-robust-intrinsic-state-shaped-by-evolution-a-key-issues-review
#14
Ruoshi Yuan, Xiaomei Zhu, Gaowei Wang, Site Li, Ping Ao
Cancer is a complex disease: its pathology cannot be properly understood in terms of independent players-genes, proteins, molecular pathways, or their simple combinations. This is similar to many-body physics of a condensed phase that many important properties are not determined by a single atom or molecule. The rapidly accumulating large 'omics' data also require a new mechanistic and global underpinning to organize for rationalizing cancer complexity. A unifying and quantitative theory was proposed by some of the present authors that cancer is a robust state formed by the endogenous molecular-cellular network, which is evolutionarily built for the developmental processes and physiological functions...
February 17, 2017: Reports on Progress in Physics
https://www.readbyqxmd.com/read/28212072/neural-network-based-solutions-for-stochastic-optimal-control-using-path-integrals
#15
Karthikeyan Rajagopal, Sivasubramanya Nadar Balakrishnan, Jerome R Busemeyer
In this paper, an offline approximate dynamic programming approach using neural networks is proposed for solving a class of finite horizon stochastic optimal control problems. There are two approaches available in the literature, one based on stochastic maximum principle (SMP) formalism and the other based on solving the stochastic Hamilton-Jacobi-Bellman (HJB) equation. However, in the presence of noise, the SMP formalism becomes complex and results in having to solve a couple of backward stochastic differential equations...
March 2017: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28211931/the-dynamic-conductance-response-and-mechanics-modulated-memristive-behavior-of-the-azurin-monolayer-under-cyclic-loads
#16
Xiaoyue Zhang, Jian Shao, Yun Chen, Weijin Chen, Jing Yu, Biao Wang, Yue Zheng
Azurin (Az) has been considered as the research hotspot in molecular electronics, as well as a promising material for building functional devices on the molecular scale because of its special electrical properties and force-dependent conductance effects. Here we carry out an in-depth investigation combined with molecular scale experiments, molecular dynamics simulations, first-principles calculations and theoretical models to reveal the dynamic conductance response of the Az monolayer under cyclic mechanical loading...
February 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28211740/ultrafast-structure-switching-through-nonlinear-phononics
#17
D M Juraschek, M Fechner, N A Spaldin
We describe a mechanism by which nonlinear phononics allows ultrafast coherent and directional control of transient structural distortions. With ErFeO_{3} as a model system, we use density functional theory to calculate the structural properties as input into an anharmonic phonon model that describes the response of the system to a pulsed optical excitation. We find that the trilinear coupling of two orthogonal infrared-active phonons to a Raman-active phonon causes a transient distortion of the lattice. In contrast to the quadratic-linear coupling that has been previously explored, the direction of the distortion is determined by the polarization of the exciting light, introducing a novel mechanism for nonlinear phononic switching...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28211703/collisional-scaling-of-the-energy-transfer-in-drift-wave-zonal-flow-turbulence
#18
B Schmid, P Manz, M Ramisch, U Stroth
The collisionality scaling of density and potential coupling together with zonal flow energy transfer and spectral power is investigated at the stellarator experiment TJ-K. With a poloidal probe array, consisting of 128 Langmuir probes, density and potential fluctuations are measured on four neighboring flux surfaces simultaneously over the complete poloidal circumference. By analyzing Reynolds stress and pseudo-Reynolds stress, it is found that, for increasing collisionality, the coupling between density and potential decreases which hinders the zonal flow drive...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28211471/phosphorene-quantum-dot-saturable-absorbers-for-ultrafast-fiber-lasers
#19
J Du, M Zhang, Z Guo, J Chen, X Zhu, G Hu, P Peng, Z Zheng, H Zhang
We fabricate ultrasmall phosphorene quantum dots (PQDs) with an average size of 2.6 ± 0.9 nm using a liquid exfoliation method involving ultrasound probe sonication followed by bath sonication. By coupling the as-prepared PQDs with microfiber evanescent light field, the PQD-based saturable absorber (SA) device exhibits ultrafast nonlinear saturable absorption property, with an optical modulation depth of 8.1% at the telecommunication band. With the integration of the all-fiber PQD-based SA, a continuous-wave passively mode-locked erbium-doped (Er-doped) laser cavity delivers stable, self-starting pulses with a pulse duration of 0...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28211134/effect-of-age-on-the-performance-of-bispectral-and-entropy-indices-during-sevoflurane-pediatric-anesthesia-a-pharmacometric-study
#20
Alberto Sciusco, Joseph F Standing, Yucheng Sheng, Pasquale Raimondo, Gilda Cinnella, Michele Dambrosio
BACKGROUND: Bispectral index (BIS) and entropy monitors have been proposed for use in children, but research has not supported their validity for infants. However, effective monitoring of young children may be even more important than for adults, to aid appropriate anesthetic dosing and reduce the chance of adverse consequences. This prospective study aimed to investigate the relationships between age and the predictive performance of BIS and entropy monitors in measuring the anesthetic drug effects within a pediatric surgery setting...
February 17, 2017: Paediatric Anaesthesia
keyword
keyword
12586
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"