Ratio-based Approach Research Articles

Incidence of SARS-CoV-2 during the Omicron wave: Results of a longitudinal serosurvey in Québec, Canada.

Conventional serological approaches lack sensitivity for the detection of recent SARS-CoV-2 infections in vaccinated individuals, as these individuals exhibit a blunted anti-nucleocapsid (N) response. This limitation was recently addressed by the development of a "ratio-based approach", which compares longitudinally collected specimens. Here, we used this approach to estimate the incidence of SARS-CoV-2 infection and reinfection in Québec (Canada) during the Omicron wave. Consenting plasma donors were included if they donated plasma before December 15, 2021 and during six consecutive periods of ~ 3months between December 15, 2021 and July 7, 2023 (study period). Anti-N levels were measured with an enzyme-linked immunosorbent assay, and seroconversion was characterized by a ratio of ≥ 1.5 between the optical density of two consecutive samples. Among the 254 donors, the adjusted proportion of donors (95% confidence interval [CI]) with a new infection ranged between 18.1% (13.2‒23.0) and 24.2% (18.8‒29.7) over Periods 1-5 and fell to 7.9% (4.9‒11.0) during Period 6. During the study period, the proportion of newly infected donors decreased among those aged < 60 (Period 1 = 31.6%, Period 5 = 4.4%), but increased among those aged ≥ 70 (Period 1 = 0.3%, Period 6 = 10.3%). Throughout the study period, 72 (28.3%) reinfections occurred, including two seroconversion events in a single donor. Overall, 87.4% (95% CI = 82.7‒91.2) were infected by SARS-CoV-2 at least once during the study period. The vast majority of the Québec population may have been infected during the Omicron wave. This longitudinal survey demonstrates the usefulness of the "ratio-based approach" for identifying both new infections and reinfections in a vaccinated population.

An enhanced indirect modal identification procedure for bridges based on the dynamic response of moving vehicles

Indirect dynamic structural identification, referred to as Vehicle Scanning Method (VSM), pertains to the estimation of bridge modal parameters by using data recorded from sensors directly mounted on a moving vehicle. This procedure has recently gained increasing attention due to its low cost and simple implementation. Nevertheless, the non-stationary and complex nature of the vehicle–bridge interaction phenomenon poses some limitations to the applicability of the method, especially in terms of accuracy. In this regard, in this paper, an enhanced procedure for the dynamic identification of bridges modal parameters based on the VSM is introduced, taking into account the effects of vehicle/bridge damping and road pavement roughness. Specifically, based on the Variational Mode Decomposition (VMD) method, the relevant Intrinsic Mode Functions (IMFs) and corresponding modal frequencies are determined from the recorded signal. Further, the Natural Excitation Technique (NExT) is adopted in conjunction with a noise-robust area ratio-based approach, for modal damping ratios estimation. Finally, mode shapes are evaluated by properly correcting the instantaneous amplitudes of each IMF considering the influence of the corresponding estimated modal damping ratio. Several numerical simulations are presented to show the validity of the proposed procedure and comparisons with the classical Hilbert Spectrum-based identification approach are employed to assess its reliability and improved accuracy.

SARS-CoV-2 immunoassays in a predominantly vaccinated population: Performances and qualitative agreements obtained with two analytical approaches and four immunoassays.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serosurveys are typically analysed by applying a fixed threshold for seropositivity ('conventional approach'). However, this approach underestimates the seroprevalence of anti-nucleocapsid (N) in vaccinated individuals-who often exhibit a difficult-to-detect anti-N response. This limitation is compounded by delays between the onset of infection and sample collection. To address this issue, we compared the performance of four immunoassays using a new analytical approach ('ratio-based approach'), which determines seropositivity based on an increase in anti-N levels. Two groups of plasma donors and four immunoassays (Elecsys total anti-N, VITROS total anti-N, Architect anti-N Immunoglobulin G (IgG) and in-house total anti-N) were evaluated. First-group donors (N = 145) had one positive SARS-CoV-2 polymerase chain reaction (PCR) test result and had made two plasma donations, including one before and one after the PCR test (median = 27 days post-PCR). Second-group donors (N = 100) had made two plasma donations early in the Omicron wave. Among first-group donors (97.9% vaccinated), sensitivity estimates ranged from 60.0% to 89.0% with the conventional approach, compared with 94.5% to 98.6% with the ratio-based approach. Among second-group donors, Fleiss's κ ranged from 0.56 to 0.83 with the conventional approach, compared with 0.90 to 1.00 with the ratio-based approach. With the conventional approach, the sensitivity of four immunoassays-measured in a predominantly vaccinated population based on samples collected ~1 month after a positive test result-fell below regulatory agencies requirement of ≥95%. The ratio-based approach significantly improved the sensitivities and qualitative agreement among immunoassays, to the point where all would meet this requirement.

Impact of Dataset Scaling on Hierarchical Clustering: A Comparative Analysis of Distance-Based and Ratio-Based Methods

In this study, the distance-based agglomerative hierarchical clustering techniques were compared to a ratio-based approach. Two real datasets, which were also used in a prior study by Roux (2018), were considered. Firstly, it was observed that the type of scaling applied to the datasets was found to affect the results of hierarchical clustering. Thus, various scaling methods were employed prior to implementing hierarchical clustering. Furthermore, two rank-based goodness-of-fit measures were used to evaluate the hierarchical clustering methods. In contrast to Roux (2018) findings, it was observed that the distance-based methods, such as Median linkage, Average linkage, and centroid linkage, performed better than the ratio-based method. The ratio-based methods also showed issues with branch crossing in the hierarchical clustering dendrogram. Consequently, this study illustrates that, with appropriate dataset scaling, the distance-based methods outperform ratio-based methods in terms of goodness-of-fit measures.

Adaptive modal identification of honeycomb thin-walled composite structures with pit defects under thermal modal testing using variational mode decomposition technique based on digital image correlation

The active imaging blue light high-speed three-dimensional digital image correlation (3D-DIC) system was combined with a transient aerodynamic heating system and random pulse excitation technology to establish a high-frequency thermal vibration optical test system capable of multi-temperature zone testing at 900 °C to accurately obtain the thermal modal parameters of thin-walled structures. The full-field temperature distribution of a novel honeycomb thin-walled composite structure (HTWCS) with pit defects under non-uniform temperature was accurately simulated through reinforcement learning. The first six modal frequencies of honeycomb thin-walled composite structure with pit defects at room temperature increased compared with the non-destructive honeycomb thin-walled composite structure, and the third and fourth modal shapes interchanged. An adaptive modal parameter identification method for full-field three-dimensional vibration measurements under high-temperature environments was developed by combining the successive multivariate variational mode decomposition (VMD) with the modal superposition method. This method can effectively identify close modes. The area ratio-based approach was used to evaluate the damping of the measured response. The finite element model (FEM) of the HTWCS with pit defects at different temperatures was updated using a multi-state step-by-step model updating method and the temperature-dependent material properties were established. The results showed that the introduction of a damping ratio improved the accuracy of the updated FEM of HTWCS with pit defects. The proposed technique is anticipated to provide an effective method for high-frequency thermal vibration optical measurement and modal identification of thin-walled structures under multi-temperature regions.

Accurate Label-Free Quantification by directLFQ to Compare Unlimited Numbers of Proteomes

Recent advances in mass spectrometry–based proteomics enable the acquisition of increasingly large datasets within relatively short times, which exposes bottlenecks in the bioinformatics pipeline. Although peptide identification is already scalable, most label-free quantification (LFQ) algorithms scale quadratic or cubic with the sample numbers, which may even preclude the analysis of large-scale data. Here we introduce directLFQ, a ratio-based approach for sample normalization and the calculation of protein intensities. It estimates quantities via aligning samples and ion traces by shifting them on top of each other in logarithmic space. Importantly, directLFQ scales linearly with the number of samples, allowing analyses of large studies to finish in minutes instead of days or months. We quantify 10,000 proteomes in 10 min and 100,000 proteomes in less than 2 h, a 1000-fold faster than some implementations of the popular LFQ algorithm MaxLFQ. In-depth characterization of directLFQ reveals excellent normalization properties and benchmark results, comparing favorably to MaxLFQ for both data-dependent acquisition and data-independent acquisition. In addition, directLFQ provides normalized peptide intensity estimates for peptide-level comparisons. It is an important part of an overall quantitative proteomic pipeline that also needs to include high sensitive statistical analysis leading to proteoform resolution. Available as an open-source Python package and a graphical user interface with a one-click installer, it can be used in the AlphaPept ecosystem as well as downstream of most common computational proteomics pipelines.

In Situ Stress Determination Based on Acoustic Image Logs and Borehole Measurements in the In-Adaoui and Bourarhat Hydrocarbon Fields, Eastern Algeria

The study of in situ stress from image logs is a key factor for understanding regional stresses and the exploitation of hydrocarbon resources. This work presents a comprehensive geomechanical analysis of two eastern Algerian hydrocarbon fields to infer the magnitudes of principal stress components and stress field orientation. Acoustic image logs and borehole measurements were used in this research to aid our understanding of regional stress and field development. The studied In-Adaoui and Bourarhat fields encompass a combined thickness of 3050 m of Paleozoic and Mesozoic stratigraphy, with the primary reservoir facies in the Ordovician interval. The Ordovician sandstone reservoir interval indicates an average Poisson’s ratio (v) of 0.3, 100–150 MPa UCS, and 27–52 GPa Young’s modulus (E). Direct formation pressure measurements indicate that the sandstone reservoir is in a hydrostatic pore pressure regime. Density-derived vertical stress had a 1.1 PSI/feet gradient. Minimum horizontal stress modeled from both Poisson’s ratio and an effective stress ratio-based approach yielded an average 0.82 PSI/feet gradient, as validated with the leak-off test data. Drilling-induced tensile fractures (DITF) and compressive failures, i.e., breakouts (BO), were identified from acoustic image logs. On the basis of the DITF criterion, the maximum horizontal stress gradient was found to be 1.57–1.71 PSI/feet, while the BO width-derived gradient was 1.27–1.37 PSI/feet. Relative stress magnitudes indicate a strike-slip stress regime. A mean SHMax orientation of N130°E (NW-SE) was interpreted from the wellbore failures, classified as B-quality stress indicators following the World Stress Map (WSM) ranking scheme. The inferred stress magnitude and orientation were in agreement with the regional trend of the western Mediterranean region and provide a basis for field development and hydraulic fracturing in the low-permeable reservoir. On the basis of the geomechanical assessments, drilling and reservoir development strategies are discussed, and optimization opportunities are identified.

A Ratio-Based approach to identifying the most basic feasible solution to bottleneck transportation problems

A Ratio-Based approach to identifying the most basic feasible solution to bottleneck transportation problems

Division vs. distributivity: Is per just like each?

This paper argues that there are lexical items that conventionally express the idea of dividing one quantity by another, and per is one of them. In particular, the proposal is that there are three ratio-related senses of per: (i) a quotient function; (ii) a quotient operator; and (iii) quotient of measure functions. The ratio-based approach, which is built up here in order to handle a wider range of data than previous ratio-based approaches could, is contrasted with an opposing view, one on which per is a distributivity marker like each. Four types of evidence are used: (i) cases involving measurement of an object or an event whose measure is smaller than the unit given by per’s complement; (ii) uses in the differential argument of a comparative; (iii) uses modifying a measure function noun; and and (iv) uses modifying a gradable predicate. All of these are problematic for a distributivity- marker analysis, and support the idea that per expresses the concept of ratio. Along the way, we gain diagnostics for whether a given item conventionally expresses the concept of a ratio in a given language.

Failure mode-based calculation method for bending bearing capacities of corroded RC beams strengthened with CFRP sheets

This paper proposed a failure mode-based calculation method for bending bearing capacities of CFRP sheet-strengthened corroded RC beams. According to the stress states of concrete, corroded steel bars and CFRP sheets at bending failure of the beam, four balanced failures and five failure modes were defined and identified. Both strengthening ratio-based approach and corrosion degree-based approach were proposed to identify failure modes. Then, the simplified calculation method was proposed for the bending bearing capacity of a CFRP sheet-strengthened corroded RC beam under each failure mode. Subsequently, a dataset with bending tests on 96 CFRP sheet-strengthened corroded RC beams and 122 CFRP-sheet strengthened non-corroded RC beams was established. The calculated bending bearing capacities were found in good agreement with experimental ones in the dataset, which demonstrated the validity of the proposed calculation method. The proposed failure mode-based calculation method enables to design strengthening ratios of CFRP sheets to achieve anticipated bending bearing capacities and bending failure modes for existing corroded RC beams (through strengthening ratio-based approach) and to assess the bending failure modes and bending bearing capacities of existing CFRP sheet-strengthened corroded RC beams (through corrosion degree-based approach), which will broaden the use of CFRP sheets in strengthening of corroded RC structures.

The Poetics and Politics of Ambiguity

The use of the harmonic series as a pitch-generating resource is a significant trend in twentieth- and twenty-first-century composition. While the principle of equal temperament prioritizes an additive understanding of intervals, the harmonic series implies a ratio-based approach to pitch relationships. Despite these philosophical differences and the sometimes polemical debates that have attended to them, the works of Julian Anderson (1967–) and Rand Steiger (1957–) draw simultaneously on overtone-based and equal-tempered harmonic thinking. These two composers are part of a group of musicians who have proposed various hybrid approaches to harmonic construction, and their works are also notable for playing out interactions between these influences in ways that reflect the composers’ political concerns. In this paper, I combine examinations of Anderson’s and Steiger’s characteristic harmonic strategies with close analyses of two quartertone-based works: Anderson’s Eden (2005) and Steiger’s Post-truth Lament (2017). I use these discussions to consider the pieces’ diverse political resonances. Ultimately, I argue that their hybrid harmonic approaches serve to highlight the multifaceted implications of ambiguity—not only its musically generative potential, but also its capacity to transform contemporary political life in ways both corrosive and constructive.

Profit Efficiency of Indian General Insurance Companies: A Ratio-Based Approach

While there are several studies regarding the technical efficiency of Indian general insurance companies, the field of profit efficiency remained relatively unexplored. The present study seeks to fill this gap. In the present article, two alternative ratio-based approaches have been adopted for the estimation of profit efficiency of Indian general insurers. The profit efficiency scores so derived are then decomposed in to revenue and cost efficiency components. In the final stage, the impact of several contextual variables on the efficiency scores are analysed. The data set for the present study includes information pertaining to 15 general insurance companies for the period 2011–12 to 2016–17. The outcome shows that the public sector insurers have done well in terms of revenue efficiency but needs to be concerned about cost efficiency. Further, the application of pooled ordinary least squares regression show that solvency ratio is an important explanatory variable of profit efficiency. Significance of the impact of return on equity on profit efficiency is, however, contingent on the model chosen. JEL Classification: C-61, D-22, G-23

Finding Targets in Non-Radial FDH Models: A Hybrid Technique Based on STEM and Extended Ratio Based Approach

Performance evaluation using interactive methods and extended ratio-based approaches can be very important for some organizations. Free disposal hull models can be created if there is no concern for convexity, and using non-radial DEA models can simultaneously create more logical and practical situations for finding DMU targets. In this paper, a new hybrid technique based on the additive slack based method and enhanced Russel measure in variable return to scale technology has been proposed. The proposed technique can find decision making unit targets in non-radial free disposal hull models using the step method. Furthermore, the extended ratio-based approach in the proposed technique has been applied to find DMU targets of related non-radial free disposal hull models without solving any mathematical programming models. Finally, targets of Fars province pharmaceutical distributing companies were found by applying the proposed hybrid technique.

Microseismic monitoring to assess rock mass damaging through a novel damping ratio-based approach

Monitoring rock mass damaging through the analysis of seismic records is an affirmed tool to manage rock fall risk in view of mitigation strategies. This study proposes a novel approach, named DAmping RaTio Anomalies Monitoring (DaRtAM), to detect the rock mass damaging by measuring variation over time of the damping ratio related to in-situ recorded vibrational events. Although damping-based damage detection techniques are well known for structural monitoring, only few applications exist for rock mass damage investigation not including in-situ long term rock mass monitoring. Here, a three-month-long seismic dataset recorded on a rock wall (Acuto Field Laboratory) by means of six one-component accelerometers was analysed with a STA/LTA algorithm that allowed to extract 19013 vibrational events. The damping ratio of the signals was derived as a function of frequency, averaged in a daily time window and analysed over time to output short-term anomalies and long-term trend. Although the limited time period analysed did not allow to observe significant trend variation of the damping ratio, 131 short-term anomalies were found in the collected seismic records. As it results from this study, the proposed approach is suitable for detecting rock mass damaging and, as a future perspective, will be applied to yearly-lasting vibrational datasets. This approach may be more effective with data acquired in environments characterised by recurrent forcings, such as coastal cliffs forced by sea and wind storms, rock walls stressed by thermal cycles, quarry walls involved in human activities or rocky trenches close to roads and railways.

Nonlinear Dynamic RF System Characterization: Envelope Intermodulation Distortion Profiles—A Noise Power Ratio-Based Approach

As radio frequency (RF) applications occupy larger bandwidths, nonlinear dynamics become nonnegligible. This work presents a theoretical framework capable of quantifying the impacts of nonlinear dynamic effects on RF systems through the observation of intermodulation distortion (IMD) profiles produced under multitone excitation. This framework defines static reference profiles and quantifies inband nonlinear dynamic effects as the error between the measured and reference profiles. This analysis demonstrates that classic linearity metrics, such as noise power ratio (NPR), adjacent-channel power ratio, and cochannel power ratio, do not have sufficient frequency resolution to reliably evaluate the impacts of nonlinear dynamics manifested in the IMD profiles produced by broadband RF systems. These observations result in a list of general characterization guidelines to overcome the limitations of classical linearity metrics in the assessment of nonlinear dynamics and the proposal and experimental validation of a novel method, swept-tone NPR, for the characterization of IMD profiles affected by nonlinear dynamic effects. Beyond this, the classic nonlinear dynamic mechanism, responsible for IMD asymmetry, is analyzed under multitone excitation at the system level for the first time, and the limitations of mechanism-based IMD analysis in the presence of nonlinear dynamic effects are evidenced with theoretical examples.

A targeted transcriptomics approach for the determination of mixture effects of pesticides

While real-life exposure occurs to complex chemical mixtures, toxicological risk assessment mostly focuses on individual compounds. There is an increasing demand for in vitro tools and strategies for mixture toxicity analysis. Based on a previously established set of hepatotoxicity marker genes, we analyzed mixture effects of non-cytotoxic concentrations of different pesticides in exposure-relevant binary mixtures in human HepaRG hepatocarcinoma cells using targeted transcriptomics. An approach for mixture analysis at the level of a complex endpoint such as a transcript pattern is presented, including mixture design based on relative transcriptomic potencies and similarities. From a mechanistic point of view, goal of the study was to evaluate combinations of chemicals with varying degrees of similarity in order to determine whether differences in mechanisms of action lead to different mixtures effects. Using a model deviation ratio-based approach for assessing mixture effects, it was revealed that most data points are consistent with the assumption of dose addition. A tendency for synergistic effects was only observed at high concentrations of some combinations of the test compounds azoxystrobin, cyproconazole, difenoconazole, propiconazole and thiacloprid, which may not be representative of human real-life exposure. In summary, the findings of our study suggest that, for the pesticide mixtures investigated, risk assessment based on the general assumption of dose addition can be considered sufficiently protective for consumers. The way of data analysis presented in this paper can pave the way for a more comprehensive use of multi-gene expression data in experimental studies related to mixture toxicity.

Time-averaged mean squared displacement ratio test for Gaussian processes with unknown diffusion coefficient.

The time-averaged mean squared displacement (TAMSD) is one of the most common statistics used for the analysis of anomalous diffusion processes. Anomalous diffusion is manifested by non-linear (mostly power-law) characteristics of the process in contrast to normal diffusion where linear characteristics are expected. One can distinguish between sub- and super-diffusive processes. We consider Gaussian anomalous diffusion models and propose a new approach used for their testing. This approach is based on the TAMSD ratio statistic for different time lags. Similar to the TAMSD, this statistic exhibits a specific behavior in the anomalous diffusion regime. Through its structure, it is independent of the diffusion coefficient, which, in general, does not influence anomalous diffusion behavior. Thus, the TAMSD ratio-based approach does not require preliminary knowledge of the diffusion coefficient's value, in contrast to the TAMSD-approach, where this value is crucial in the testing procedure. Based on the quadratic form representation of the TAMSD ratio, we calculate its main characteristics and propose a step-by-step testing procedure that can be applied for any Gaussian process. For the anomalous diffusion model used here, namely, the fractional Brownian motion, we demonstrate the effectiveness of the proposed methodology. We show that the new approach outperforms the TAMSD-based one, especially for small sample sizes. Finally, the methodology is applied to the real data from the financial market.

Breaking with Trends in Forensic Dating: A Likelihood Ratio-Based Approach for Estimating Time Elapsed Since Bloodstains Deposition

Breaking with Trends in Forensic Dating: A Likelihood Ratio-Based Approach for Estimating Time Elapsed Since Bloodstains Deposition

Molecular Tetrahedrons as Selective and Efficient Ion Transporters via a Two-Station Swing-Relay Mechanism

The traditional approach to utilizing an ion-relay mechanism for ion transport requires three or more ion-relay stations. Herein, we describe a novel strategy, incorporating a swing action to reali...

Plastic design of knee-element connection frames (KCFs) using mechanism control

In the past two decades, extensive research has been conducted to evaluate the seismic performance of Knee-element Connection Frames (KCFs) and to determine the most efficient configurations. KCFs are of particular advantage over other load-resisting systems in terms of their ample access for maintenance and enhanced structural performance. This paper presents an enhanced energy-based plastic design for KCFs using mechanism control. The design methodology developed in this study constitutes the design criteria employed in Performance-based Plastic Design (PBPD) and Theory of Plastic Mechanism Control (TPMC) at the same time. In this design approach, the external forces are derived from the energy balance equation directly considering second-order effects, and design is carried out according to the PBPD method. Then, undesired collapse mechanisms are identified and prevented by the use of a Design-Capacity Ratio-based (DCR-based) approach as the controlling criteria. To evaluate the design performance, nonlinear static and dynamic analyses were performed. The results indicate an acceptable correlation between the expected general yield mechanism and structural response and an acceptable economy in terms of material usage compared to comparable moment resisting frames.