Sensitivity Formula Research Articles

Long-term straw return enhanced the chlorine reactivity of soil DOM: Highlighting the molecular-level activity and transformation trade-offs

Chemical properties and molecular diversity of dissolved organic matter (DOM) in agricultural soils are important for soil carbon dynamics and chlorine activity. Yet the chlorine reactivity of soil DOM at the molecular level under agricultural management practices remains unidentified. Here, we investigated the chlorine reactivity of soil DOM under long-term straw return and the molecular activities and transformations during chlorination. The 9-year straw return enhanced the chlorine reactivity of soil DOM, leading to increases in the production of traditional disinfection byproducts (DBPs) and decreases in the formation of emerging high molecular weight DBPs. C17HnOmCl1–2 and C22HnNmOzCl were the highest relative abundances of emerging DBPs. The emerging DBPs were primarily generated through chlorine substitution reactions, with their precursors exhibiting higher H/Cwa (1.47) and O/Cwa (0.41) ratios under straw return. The molecular transformation ability and inactive molecules of soil DOM under long-term straw return were reduced after chlorination, resulting in increased DOM instability. Chlorination led to a shift in the thermodynamic processes of soil DOM molecules from thermodynamically limited to thermodynamically favorable processes, and lignin-like compounds displayed higher potentials for transformation into protein/amino sugar-like compounds. C19H26O6 was identified as a sensitive formula for tracing chlorine reactivity under straw return, and a network illustrating the generation of DBPs from C19H26O6 was established. Overall, these results highlighted the strong chlorine reactivity of soil DOM under long-term straw return.

Isogeometric Topology Optimization of Multi-Material Structures under Thermal-Mechanical Loadings Using Neural Networks

An isogeometric topology optimization (ITO) model for multi-material structures under thermal-mechanical loadings using neural networks is proposed. In the proposed model, a non-uniform rational B-spline (NURBS) function is employed for geometric description and analytical calculation, which realizes the unification of the geometry and computational models. Neural networks replace the optimization algorithms of traditional topology optimization to update the relative densities of multi-material structures. The weights and biases of neural networks are taken as design variables and updated by automatic differentiation without derivation of the sensitivity formula. In addition, the grid elements can be refined directly by increasing the number of refinement nodes, resulting in high-resolution optimal topology without extra computational costs. To obtain comprehensive performance from ITO for multi-material structures, a weighting coefficient is introduced to regulate the proportion between thermal compliance and compliance in the loss function. Some numerical examples are given and the validity is verified by performance analysis. The optimal topological structures obtained based on the proposed model exhibit both excellent heat dissipation and stiffness performance under thermal-mechanical loadings.

Top-Down Design Method of a Time Domain Accelerometer with Adjustable Resolution.

A top-down design methodology and implementation of a time domain sensor is presented in this paper. The acceleration resolution of the time domain sensor is equal to the time-measurement accuracy divided by the sensor sensitivity. Combined with the sensitivity formula, the acceleration resolution is proportional to the vibration amplitude, the time-measurement accuracy, and the third power of the resonant frequency. According to the available time-measurement accuracy and the desired acceleration resolution, the parameters including the vibration amplitude and the resonant frequency were theoretically calculated. The geometrical configuration of the time domain sensor device was designed based on the calculated parameters. Then, the designed device was fabricated based on a standard silicon-on-insulator process and a matched interface circuit was developed for the fabricated device. Experimental results demonstrated that the design methodology is effective and feasible. Moreover, the implemented sensor works well. In addition, the acceleration resolution can be tuned by adjusting the time-measurement accuracy and the vibration amplitude. All the reported results of this work can be expanded to other time domain inertial sensors, e.g., a gyroscope or tilt sensor.

Sensitivity analysis for matched observational studies with continuous exposures and binary outcomes

Summary Matching is one of the most widely used study designs for adjusting for measured confounders in observational studies. However, unmeasured confounding may exist and cannot be removed by matching. Therefore, a sensitivity analysis is typically needed to assess a causal conclusion’s sensitivity to unmeasured confounding. Sensitivity analysis frameworks for binary exposures have been well-established for various matching designs and are commonly used in various studies. However, unlike the binary exposure case, there still lacks valid and general sensitivity analysis methods for continuous exposures, except in some special cases such as pair matching. To fill this gap in the binary outcome case, we develop a sensitivity analysis framework for general matching designs with continuous exposures and binary outcomes. First, we use probabilistic lattice theory to show our sensitivity analysis approach is finite-population- exact under Fisher’s sharp null. Second, we prove a novel design sensitivity formula as a powerful tool for asymptotically evaluating the performance of our sensitivity analysis approach. Third, to allow effect heterogeneity with binary outcomes, we introduce a framework for conducting asymptotically exact inference and sensitivity analysis on generalized attributable effects with binary outcomes via mixed- integer programming. Fourth, for the continuous outcomes case, we show that conducting an asymptotically exact sensitivity analysis in matched observational studies when both the exposures and outcomes are continuous is generally NP-hard, except in some special cases such as pair matching. As a real data application, we apply our new methods to study the effect of early-life lead exposure on juvenile delinquency. An implementation of the methods in this work is available in the R package doseSens.

Development of a Fiber Bragg Grating accelerometer based on a tandem single-notched hinge structure

A Fiber Bragg Grating low-frequency accelerometer with a single-notched hinge in series is proposed to improve the hinge structure’s sensitivity and the cross-sensitivity of the accelerometer of low-frequency seismic waves. The sensitivity and the cross-sensitivity of the accelerometer are improved by connecting the single-notched hinge structure in series and experimentally verified. Based on the theoretical analysis, the resonance frequency and sensitivity formula of the accelerometer are derived. At the same time, the accelerometer is simulated by finite element analysis software to simulate and analyze the characteristics of the accelerometer in terms of resonance frequency, strain distribution, and amplitude-frequency response. The structural parameters of the accelerometer are optimized by numerical analysis software, and the effects of the structural parameters on the sensitivity and resonance frequency of the accelerometer are analyzed. The experimental results show that the resonance frequency of the accelerometer is 110 Hz, the flat region is 0.6–50 Hz, the linearity is as high as 98.9%, the sensitivity is 1040.41 pm/g, and the cross-sensitivity of the accelerometer in the flat interval is 4.94%. This indicates that the accelerometer shows good linearity and cross-sensitivity in the flat interval, which well meets the needs of seismic wave signal monitoring in low-frequency oil and gas exploration.

An Analytical Formula for Small Signal Stability Sensitivity Using SDP Dual

An Analytical Formula for Small Signal Stability Sensitivity Using SDP Dual

A weakly nonlinear amplitude equation approach to the bypass transition in the two-dimensional Lamb–Oseen vortex

We analytically derive an amplitude equation for the weakly nonlinear evolution of the linearly most amplified response of a non-normal dynamical system. The development generalizes the method proposed in Ducimetière et al. (J. Fluid Mech., vol. 947, 2022, A43), in that the base flow now arbitrarily depends on time, and the operator exponential formalism for the evolution of the perturbation is not used. Applied to the two-dimensional Lamb–Oseen vortex, the amplitude equation successfully predicts the nonlinearities to weaken or reinforce the transient gain in the weakly nonlinear regime. In particular, the minimum amplitude of the linear optimal initial perturbation required for the amplitude equation to lose a solution, interpreted as the flow experiencing a bypass (subcritical) transition, is found to decay as a power law with the Reynolds number. Although with a different exponent, this is recovered in direct numerical simulations, showing a transition towards a tripolar state. The simplicity of the amplitude equation and the link made with the sensitivity formula permits a physical interpretation of nonlinear effects, in light of existing work on Landau damping and on shear instabilities. The amplitude equation also quantifies the respective contributions of the second harmonic and the spatial mean flow distortion in the nonlinear modification of the gain.

Introducing the original web score calculator GARDENIA risk score for severe coronary artery (re)stenosis

Abstract Background/Introduction There are a large number of scores that are used for cardiovascular risk assessment and different online calculators are used to perform it. Risk prediction models provide risk estimates that can assist our decision making and improve guiding for individual clinical outcomes and personalized preventive care. Purpose GARDENIA score is designed to predict highly suspicious probability of significant coronary stenosis in patients without proven CAD or those who have already been revascularized. Methods GAR²DE²NIA is an acronym that incorporates following parameters : Gender, Age, Renal impairment, Respiratory disease, Diabetes Melittus, Echo abnormalities, ECG abnormalities, New symptoms, Ischaemia, Atrial fibrillation. The pointing scale was formed (-1 to 2) on the personal interpretation of evidence based data and is applied and designed as web calculator. The established cut-off values for the risk of significant coronary stenosis is 4. For values below 4, the probability of significant CAD is low, below 0 is very low, equal or greater than 4 significant CAD is high and above 8 is very high. Results Standard statistical formulas for sensitivity, specificity, PPN and NPV were used ( sensitivity 91,43%, specificity 73,33%, PPV 88,89, NPV 78,57). Estimated pilot sample size of 100 patients, was tested on patients cohort treated at the Institute for Cardiovascular Disease Dedinje in the year of 2022. Conclusion This original score is to be checked throughout everyday clinical practice. It is easy to use. It can help in decision making in risk stratification and further treatment of the patients who has never been to cardiologist before, those who has already been revascularized and are symptomatic again or need any kind of non cardiac surgery and the patients we have doubts about what to do next.GARDENIA score calculator

A novel semi-analytical meshless method for the thickness optimization of porous material distributed on sound barriers

This paper presents a novel semi-analytical meshless method to optimize the thickness of porous material distributed on sound barriers, by employing the Burton–Miller-type singular boundary method in conjunction with the method of moving asymptotes. Firstly, the Delany–Bazley–Miki model is utilized to characterize the acoustic property of sound barrier with a porous sound-absorbing material. Then, the sensitivity formula with respect to the thickness of the porous layer is derived based on the analytical computation and the adjoint variable formula, in which the design variable is a thickness parameter distributed between [0,1]. Finally, the optimal thickness distribution is achieved by solving the optimization model using the method of moving asymptotes. Compared to traditional algorithms, the proposed new method is simple, accurate, easy-to-program, and free of mesh and integration. Numerical experiments demonstrate the feasibility and effectiveness of the proposed algorithm.

Impact of feeding volumes in the first 24 h of life on neonatal feeding intolerance.

This study investigates whether volumes of intake in the first 24 h of life (24 HOL), in relation to birth weight (BW) and gestational age (GA), impact neonatal feeding intolerance (FI). This study employed a retrospective chart review of 6,650 infants born at ≥35 weeks. The volumes of each formula feed per kg BW in the first 24 HOL were assessed. FI was defined as evidenced by chart documentation of emesis, abdominal distension, abdominal x-ray, and/or switching to a sensitive formula. Overall, the maximum volume of formula intake per feed was inversely correlated with GA and was higher in infants with FI (β = -1.39, p < 0.001) compared with infants without FI (β = -1.28, p < 0.001). The odds of emesis in late preterm infants with first feeding of >8 ml/kg [adjusted odds ratio (AOR) = 2.5, 95% confidence interval (CI): 1.4-4.6] and formula switching in the exclusively formula-fed group with volumes >10.5 ml/kg [AOR = 2.2, 95% CI (1.8-2.6)] were high. In the breastfeeding group, the odds of FI increased by 2.8-, 4.6-, and 5.2-fold with 5-10, 10-15, and >15 ml/kg of supplementations, respectively. A higher volume of intake in relation to BW often exceeds the physiological stomach capacity of newborns and is associated with early FI. Optimizing early feeding volumes based on infant BW and GA may decrease FI, which may be an issue of volume intolerance.

Theoretical and experimental study of optical diffractometry based on Fresnel diffraction from a transmission phase step.

We present experiments to study the optical diffractometry of Fresnel diffraction from transmission phase steps under illuminating sources with distinct spatial profiles. The experimental results are extended analytically with the Fresnel Gaussian shape invariant introduced in previous publications to calculate the propagation of a coherent illuminating source through optical setups. We use a narrow coherent illuminating source to permit extending the applicability of the method for clinical purposes and perform calculations with illuminating sources with different spatial profiles, including a non-diffracting Airy beam, to allow for the establishment of general sensitivity formulae within the paraxial region.

New Theoretical Model for Mass Sensitivity of Love Wave Sensors

In this work we analyse basic characteristics of Love wave sensors implemented in waveguide structures composed of a lossy viscoelastic surface layer deposited on a lossless elastic substrate. It has to be noted that Love wave sensors working at ultrasonic frequencies have the highest mass density sensitivity $S_σ^(v_p )$ among all known ultrasonic sensors, such as QCM, Lamb wave or Rayleigh wave sensors. In this paper we have established an exact analytical formula for the mass density sensitivity $S_σ^(v_p )$ of the Love wave sensors in the form of an explicit algebraic expression. Subsequently, using this developed analytical formula, we compared theoretically the mass density sensitivity $S_σ^(v_p )$ for various Love wave waveguide structures, such as: (1) lossy PMMA surface layer on lossless Quartz substrate and (2) lossy PMMA on lossless Diamond substrate. The performed analysis shows that the mass density sensitivity $S_σ^(v_p )$ (real and imaginary part) for a sensor with a structure PMMA on Diamond is five times higher than that of a PMMA on Quartz structure. It was found that the mass density sensitivity $S_σ^(v_p )$ for Love wave sensors increases with the increase of the ratio: bulk shear wave velocity in the substrate to bulk shear wave velocity in the surface layer.

Mechanism and tuning sensitivity of symmetry-protected resonances in high-contrast gratings.

We develop a theory of refractive index tuning for symmetry-protected optical bound states (SP-BICs) in high-contrast gratings (HCGs). A compact analytical formula for tuning sensitivity is derived and verified numerically. We also discover a new type of SP-BIC in HCGs that has an accidental nature with a spectral singularity, which is explained in terms of hybridization and strong coupling among the odd- and even-symmetric waveguide-array modes. Our work elucidates the physics of tuning SP-BICs in HCGs and significantly simplifies their design and optimization for dynamic applications in light modulation, tunable filtering, and sensing.

Continuum Sensitivity Analysis for Shape Optimization of Transient Eddy Current Systems

This study proposes a shape sensitivity analysis for transient eddy current systems. The continuum sensitivity analysis is a deterministic optimization technique for designing the shape and topology of electromagnetic systems. Despite substantial research on the sensitivity analysis, most of the work has focused on static and steady-state issues. However, some problems require transient analysis. In this paper, the shape sensitivity formula for a transient eddy current system was derived by the continuum approach using the adjoint variable technique and material derivative concept. In the sensitivity analysis using the derived sensitivity formula, the state variable equation is an initial-value problem to be solved forward in time. Conversely, the adjoint variable equation is a terminal-value problem to be solved backward in time. Three numerical examples were tested to demonstrate the feasibility and usability of the derived sensitivity formula.

Predicting and Controlling Spillover in Multispecies Disease Transmission Networks: Steady-State Analysis.

AbstractIn multispecies disease systems, pathogen spillover from a "reservoir community" can maintain disease in a "sink community" where it would otherwise die out. We develop and analyze models for spillover and disease spread in sink communities, focusing on questions of control: which species or transmission links are the most important to target to reduce the disease impact on a species of concern? Our analysis focuses on steady-state disease prevalence, assuming that the timescale of interest is long compared with that of disease introduction and establishment in the sink community. We identify three regimes as the sink community R0 scales from 0 to 1. Up to , overall infection patterns are dominated by direct exogenous infections and one-step subsequent transmission. For , infection patterns are characterized by dominant eigenvectors of a force-of-infection matrix. In between, additional network details can be important; we derive and apply general sensitivity formulas that identify particularly important links and species.

Composition Analysis and Identification of Ancient Glass Products

Glass products are an important material evidence of the early trade exchanges between China and the West. Under the influence of buried environment, the weathering of glass leads to the change of its chemical composition proportion, which then affects the judgment of cultural relic category. This paper analyzes and identifies the components of ancient glass products by combining sample data. In order to analyze the influencing factors of weathering of cultural relics samples, the paper analyzes the high potassium and lead barium glass types and observes the relationship between the pattern and color of the sample, and the whole chi square independence test is used to obtain the difference rules of glass category, decoration and color classification. For the chemical composition content prediction, the prediction model was built and predicted by the sample mean difference. In this paper, the chemical composition of the unknown category of glass relics was analyzed and identified by training on the valid data in Form 2. For the sensitivity of the classification results, the sensitivity formula was applied to calculate a sensitivity of 0.125.

Optimal Design of a Six‐Dimensional Force Sensor with Three‐Beam Structure

A six‐dimensional force sensor with a three‐beam structure was designed, and its strain and stress distribution under various load conditions were analyzed based on finite element simulation technology. According to the strain distribution, the Wheatstone bridge scheme of the sensor is designed, and the output voltage and sensitivity formulas in each direction are deduced. The optimal patch location was determined according to the strain distribution on the centerline of the strain beam. Finally, the size parameters of the elastic body were optimized based on the response surface method and multiobjective genetic algorithm, which greatly improved the sensitivity of the sensor in all directions. It can provide a useful guidance for the optimal design of the six‐dimensional force sensor with a three‐beam structure.

Gar²De²Nia Risk Score as a New Scoring for Severe Coronary Artery Restenosis and It’s Introducing as a Web Score CalculatorPilot Study

Objectives: Gar²De²Nia score is designed to predict highly suspicious probability of significant coronary stenosis in patients without proven CAD or those who have already been revascularized. Background: There are a large number of scores that are used for cardiovascular risk assessment and different online calculators are used to perform it. Risk prediction models provide risk estimates that can assist our decision making and improve guiding for individual clinical outcomes and personalized preventive care. Methodology: Gar²De²Nia is an acronym that incorporates following parameters: Gender, Age, Renal impairement, Respiratory disease, Diabetes Melittus, Echo abnormalities, ECG abnormalities, new symptoms, Ischaemia, Atrial fibrillation. The pointing scale was formed (-1 to 2) on the personal interpretation of evidence based data and is applied and designed as web calculator. The established cut-off values for the risk of significant coronary stenosis are 4. For values below 4, the probability of significant CAD is low, below 0 is very low, equal or greater than 4 significant CAD is high and above 8 is very high. https://www.gardenia.estavela.in.rs Results: Standard statistical formulas for sensitivity, specificity, PPN and NPV were used (sensitivity 91, 43%, specificity 73, 33%, PPV 88, 89, NPV 78, 57). Estimated pilot sample size of 100 patients, was tested on patients cohort treated at the Institute for Cardiovascular Disease Dedinje in the year of 2022. Conclusion: This original score is to be checked throughout everyday clinical practice. It is easy to use. It can help in decision making in risk stratification and further treatment of the patients who has never been to cardiologist before, those who has already been revascularized and are symptomatic again or need any kind of non-cardiac surgery and the patients we have doubts about what to do next.

Comparison of two different contrast sensitivity devices in young adults with normal visual acuity with or without refractive surgery

This study investigated the reliability and correlation of two contrast sensitivity test (CST) devices in young adults with normal visual acuity, with or without refractive surgery. 57 patients aged 20–39 years who received both manual (OPTEC-6500) and automated CST (CGT-2000) examinations from June 19 to July 24, 2021 were retrospectively enrolled. Patients with corrected visual acuity under 20/20 or history of ocular surgery other than refractive surgery were excluded. 82 eyes of 41 patients (40 eyes with and 42 without history of refractive surgery) were enrolled. Mean time taken to complete each examination was 396.4 ± 20.4 and 286.8 ± 2.3 s using manual and automated CST, respectively (P < 0.001). Patients who underwent refractive surgery had significantly decreased area under the log contrast sensitivity formula (AULCSF) in mesopic compared with photopic conditions in automated CST examinations (AULCSF difference 0.415 vs. 0.323 in patients with and without refractive surgery, P < 0.001), but there was no significant difference in manual CST examinations. Patients who reported decreased subjective night vision had significantly decreased AULCSF in automated CST examinations, but there was no significant difference in manual CST examinations. Compared with manual CST, automated CST was quicker and correlated well with decrease in subjective night vision.

Derivation of a continuous adjoint topology optimization method applied on heat transfer for incompressible flow

With the development of additive manufacturing, the freedom in developing complex cooling structures has been enlarged greatly. Topology optimization is one of the methods that can give out cooling structures beyond the limits of geometric parameters. In this research, an algorithm of topology optimization with heat transfer is derived. The detailed optimization procedure is presented in this work. The basic assumptions of this optimization method are steady state, incompressible and frozen turbulent flow with constant physical properties. The governing equations, optimization sensitivity formula and boundary conditions are presented, which are essential to the implementation of this method. A detailed derivation process is included. This method is applied in a 2-D flow domain using an open-source platform named OpenFOAM.