Measurement Bias Research Articles

Examining the local Universe isotropy with galaxy cluster velocity dispersion scaling relations

In standard cosmology, the Universe is assumed to be statistically homogeneous and isotropic. This assumption suggests that the expansion rate of the Universe, as measured by the Hubble parameter, should be the same in all directions. However, our recent study based on galaxy clusters finds an apparent angular variation of approximately $9<!PCT!>$ in the Hubble constant, $H_0$, across the sky. In the study, the authors utilised galaxy cluster scaling relations between various cosmology-dependent cluster properties and a cosmology-independent property, i.e. the temperature of the intracluster gas ($T$). A position-dependent systematic bias of $T$ measurements can, in principle, result in an overestimation of apparent $H_0$ variations. Therefore, it is crucial to confirm or exclude this possibility. In this work, we search for directional $T$ measurement biases by examining the relationship between the member galaxy velocity dispersion and gas temperature ($ v -T$) of galaxy clusters. Both measurements are independent of any cosmological assumptions and do not suffer from the same potential systematic biases. Additionally, we search for apparent $H_0$ angular variations independently of $T$ by analysing the relations between the X-ray luminosity and Sunyaev-Zeldovich signal with the velocity dispersion, $L_ X v $ and $Y_ SZ v To study the angular variation of scaling relation parameters, we determined the latter for different sky patches across the extra-galactic sky. We constrained the possible directional $T$ bias using the $ v -T$ relation, as well as the apparent $H_0$ variations using the $L_ X v $ and $Y_ SZ v $ relations. We utilised Monte Carlo simulations of isotropic cluster samples to quantify the statistical significance of any observed anisotropies. We calculated and rigorously took into account a correlation of $L_ X $ and $Y_ SZ $ residuals. No significant directional $T$ measurement biases are found from the $ v -T$ anisotropy study. The probability that the previously observed $H_0$ anisotropy is caused by a directional $T$ bias is only $0.002<!PCT!>$. On the other hand, from the joint analysis of the $L_ X v $ and $Y_ SZ v $ relations, the maximum variation of $H_0$ is found in the direction of $(295^ with a statistical significance of $3.64 fully consistent with our previous results. Our findings, based on the analysis of new scaling relations utilising a completely independent cluster property, $ v $, strongly corroborate the previously detected anisotropy of galaxy cluster scaling relations. The underlying cause, for example, $H_0$ angular variation or large-scale bulk flows of matter, remains to be identified.

Inter-Vendor differences in speckle tracking strain - A ten year follow-up on the Strain Standardization Task Force Inter-Vendor Comparison Study

Abstract Background Global longitudinal strain (GLS) derived from two-dimensional speckle-tracking echocardiography is feasible and accurate. Nonetheless, in 2013, the Inter-Vendor Comparison Study showed significant differences of measurement results among vendors. In order to make tracking-based strain imaging a clinically accepted and useful parameter, it is of outmost importance to have interchangeable and accurate measurement results from all vendors. Purpose To investigate if the efforts of the EACVI/ASE/Industry Task Force to Standardize Deformation Imaging have led to a reduction of inter-vendor differences during the past ten years. Methods In an unique setting, in one single room, 372 echocardiographic examinations were performed in sixty-two subjects (50 male, age 56.1 ± 16.98) with a wide range of left ventricular (LV) function (ejection fraction from 30% to 64%) using ultrasound systems from six manufacturers. Each subject was scanned consecutively on all machines by the same assigned experienced sonographer. For each subject two image sets of LV apical views were acquired in order to assess reproducibility in a true test-retest setting. We assessed mean GLS (GLSAV) as average peak systolic global strain from the three apical views on five vendor-specific and five vendor-independent software solutions. We measured endocardial and mid-/full-wall GLS. Since there is no gold standard method to measure GLS, we compared GLSAV of each vendor to the average of the GLS values only from vendors that provide tracking software solutions (SWS) for clinical use. Results For both endocardial (Figure 1) and mid-/full-wall (Figure 2) GLS measurements from clinical SWS were comparable and within a very narrow range (mean GLS of vendors 17.25 ± 0.3% and 15.36 ± 0.3% respectively). The maximum absolute difference between all SWS was 4.1% and 4.9% strain units for endocardial and mid-/full-wall GLS respectively. GLSAV of each software versus the mean of clinical SWS showed significant correlation for most of the companies (r² >0.8, p<0.001). Test-retest variability of GLS measurements expressed as relative mean error was good and lower than for LV ejection fraction (6.3% on average for mean GLS and 7% for LV ejection fraction, p>0.05). Conclusions Our data show a substantial inter-vendor bias in GLS measurements. Nevertheless, in contrast to the situation ten years ago, companies that provide tracking software solutions for clinical use provide now very similar GLS values. In addition, most companies do now allow mid-/full-wall tracking. Our data indicate that the efforts of the strain standardization task force have been fruitful. A continuing effort is needed until all software providers adhere to the task force consensus recommendations.Figure 1Figure 2

Combining fractional flow reserve and the index of microcirculatory resistance for prognosis prediction in renal artery stenosis interventions: a feasibility sub-study of FAIR-pilot trial

Abstract Background Interventional therapies for renal artery stenosis (RAS) was debatable in previous randomized trials. Fractional flow reserve (FFR), while useful in coronary interventions, does not assess microcirculatory status, which may be critical in RAS. The index of microcirculatory resistance (IMR) provides additional microvascular information, which has not been used in RAS patients. Purpose To investigate the feasibility of IMR measurement in RAS patients and the association with the outcome. Methods FAIR-pilot study is a multicenter pilot randomized controlled trial exploring the application of FFR to guide the renal artery stenting in patients with renovascular hypertension (NCT05732077). A pressure-temperature sensor guidewire was used to measure the IMR. To derive mean transit time at rest, thermodilution curves were obtained by 3 injections of 4 mL of room temperature saline down the renal artery. Hyperemia was induced using dopamine 50μg/kg bolus to the renal artery. The IMR was calculated as distal arterial pressure (Pd) x mean transit time during hyperemia (TmnH) (Figure 1). Prognostic evaluation was based on improvements in postoperative blood pressure, which was assessed using both ambulatory blood pressure monitor (ABPM) and anti-hypertensive medication number, along with renal function, as determined by the estimated glomerular filtration rate (eGFR). Results The IMR was measured among five patients enrolled in FAIR-pilot study. As shown in Table 1 and 2, stent implantation was conducted on five lesions across patients 1 to 4 based on renal FFR < 0.8, with each experiencing varying degrees of improved blood pressure control subsequently. Patient 5 did not receive a stent and was lost to follow-up. At three-month, the recorded decrease in systolic blood pressure ranged from a maximum of 34 mmHg to a minimum decrease of -6 mmHg among the four patients. The antihypertensive medication number showed a maximum reduction of 2 and no change as the minimum. We observed a correlation between baseline IMR and baseline renal function. No significant change in IMR was noted after interventional procedures. Preliminary findings suggest that IMR measurement is feasible in patients with RAS, while the ∆T (temperature change time) was very small, which potentially increasing the measurement bias. Conclusion The study suggests measuring IMR in patients with RAS is feasible and can offer information into the renal microvasculature. However, the small ∆T encountered during measurement may introduce increased bias, which should be considered when interpreting results.

The Export Dilemma of China under the WTO Framework: An Anti-Dumping Study on the Determination of Market Economy Status

As China emerges as a dominant force in the global economy, the issue of non-market economy status has become a key issue, particularly in the face of biased anti-dumping measures enforced by other nations. These measures have seriously affected China's export-oriented economy by creating substantial trade barriers. The essay utilizes a blend of literature review, comparative analysis, and data examination, drawing on historical experience and the legal principles and rules as outlined in the WTO agreements. The results show that although China has achieved certain advancements in pursuing acknowledgment of its market economy status, it still faces significant challenges due to political and economic factors.This essay will discuss anti-dumping measures exert considerable pressure on businesses operating within developing economies, and on this basis, it will provide corresponding thoughts and suggestions for China to secure the market economy status, and for Chinese enterprises not to be hit by it as far as possible.

Systematic Review of Associations between Anxiety, Depression, and Functional/Biological aging among Cancer Survivors.

Evidence suggests a mind-body component to aging, through which psychological distress from anxiety and depression drives molecular changes that promote early decline (ie, accelerated aging). Cancer survivors experience particularly high rates of anxiety and depression. Some survivors also have accelerated aging, though the relationships between anxiety/depression and aging are not clear. A synthesis of evidence is needed to understand the state of the science and impending priorities. PubMed, Embase, CINAHL, Web of Science, and PsycNet databases were searched for studies that measured associations between depression, anxiety, and non-chronological aging in cancer survivors (2012 to 2022). Data were methodologically evaluated. Survivorship studies were included if they were peer-reviewed, published in English from 2012-2022, and measured associations between anxiety/depression and aging. 51 studies were included. Just over half were cross-sectional (53%). Foci included functional (n = 35, 69%) and biological (n = 16, 31%). Functional aging measures included frailty, sarcopenia, geriatric assessment, and cognition. Biological aging measures included telomere length, telomerase, age-related inflammatory blood-based biomarkers, renal insufficiency, anemia, and DNA methylation. 223 associations were tested. Associations between anxiety, depression and aging were generally positive, though with varying strengths. Most compelling were associations between functional aging-depression. There were concerns for selection and measurement biases. Findings suggest positive associations between anxiety, depression and aging among cancer survivors. Future work is needed to clarify temporality, develop a consensus on the operationalization of aging, and diversify cohorts.

Analyzing Potential Non-Ignorable Selection Bias in an Off-Wave Mail Survey Implemented in a Long-Standing Panel Study

Abstract Typical design-based methods for weighting probability samples rely on several assumptions, including the random selection of sampled units according to known probabilities of selection and ignorable unit nonresponse. If any of these assumptions are not met, weighting methods that account for the probabilities of selection, nonresponse, and calibration may not fully account for the potential selection bias in a given sample, which could produce misleading population estimates. This analysis investigates possible selection bias in the 2019 Health Survey Mailer (HSM), a sub-study of the longitudinal Health and Retirement Study (HRS). The primary HRS data collection has occurred in “even” years since 1992, but additional survey data collections take place in the “off-wave” odd years via mailed invitations sent to selected participants. While the HSM achieved a high response rate (83 percent), the assumption of ignorable probability-based selection of HRS panel members may not hold due to the eligibility criteria that were imposed. To investigate this possible non-ignorable selection bias, our analysis utilizes a novel analysis method for estimating measures of unadjusted bias for proportions (MUBP), introduced by Andridge et al. in 2019. This method incorporates aggregate information from the larger HRS target population, including means, variances, and covariances for key covariates related to the HSM variables, to inform estimates of proportions. We explore potential non-ignorable selection bias by comparing proportions calculated from the HSM under three conditions: ignoring HRS weights, weighting based on the usual design-based approach for HRS “off-wave” mail surveys, and using the MUBP adjustment. We find examples of differences between the weighted and MUBP-adjusted estimates in four out of ten outcomes we analyzed. However, these differences are modest, and while this result gives some evidence of non-ignorable selection bias, typical design-based weighting methods are sufficient for correcting for it and their use is appropriate in this case.

Tunable Ambipolar Transport in a 2D Kagome Semiconductor

AbstractThe interference of electronic wavefunctions within a Kagome lattice can result in a flat band structure, where low‐energy electrons exhibit highly correlated behavior, facilitating exploration of interactions among intriguing electronic states. However, the inherent high carrier density in most known Kagome materials often hampers the manipulation of these quantum phenomena through conventional means, such as gate voltage. In this work, a unique tunability in the electrical and optoelectronic properties of exfoliated Nb3I8, a 2D semiconductor featuring a “breathing” Kagome lattice is uncovered. Characterization via temperature‐dependent ARPES confirms its semiconducting nature with a flat band structure. Experimental results from bias and gate voltage dependent transport measurements on thin film Nb3I8 transistor devices demonstrate ambipolar conductance. Notably, these findings reveal a broadband photoresponse in the device, spanning from visible to near infrared wavelengths (532 −1100 nm), with the photocurrent showing gate‐dependent characteristics that mirror the dark current's ambipolar nature. This observation marks the first instance of ambipolar transport in a Kagome semiconductor, opening up exciting new avenues for electronic and optoelectronic device development.

Economic policy uncertainty and dividend policy: Insight from private firms

This study examines whether economic policy uncertainty (EPU) is associated with corporate dividend policy. Using a sample of private firms, we find that EPU is negatively related to dividend payouts. Our main findings are robust to endogeneity concerns, omitted variable problems, simultaneity bias, and alternative measures of EPU. Further, we find that firms are less likely to pay dividends when EPU is higher, confirming our main results. We also find that the negative relation between EPU and dividend payouts is stronger for firms with higher leverage, operating cash flows, sales growth, return on assets, and cash flow volatility than their counterparts. In contrast, the negative relation is weaker for firms with higher retained earnings-to-total equity ratios. Our study highlights that issues such as EPU can influence the dividend payout policies of private firms.

The impact of rural health insurance on vulnerability to chronic poverty among rural residents in China: analysis using Probit and IVprobit models

IntroductionPoverty is a global problem, and combating it is a major governance issue worldwide. In China, poverty management efforts have shifted from eliminating absolute poverty to managing relative poverty. One of the most important tasks in managing relative poverty in the post-poverty reduction era is to prevent recurring poverty due to illness. Rural health insurance is an important method of preventing and mitigating disease risk and a key part of China’s poverty reduction policy, including among rural residents. However, the mechanism by which basic health insurance alleviates vulnerability to poverty, the causal effect of rural health insurance on vulnerability to poverty, and differences based on having a second health insurance policy and by age and income have not been sufficiently explored. Therefore, this study examined the impact of rural health insurance on vulnerability to long-term poverty among rural residents in China. In addition, this study evaluated the impact of having a second health insurance policy and differences in the effects of rural health insurance by age and income.MethodsThis study used data from the 2014, 2016, 2018, and 2020 China Family Panel Studies. Household-related characteristics, such as finance, education, and healthcare, were retrieved from the household database; while data on healthcare expenditures, healthcare insurance, and personal-related characteristics were retrieved from the adult database. Robustness tests were conducted with Probit models, and endogeneity tests were conducted with IVprobit models.ResultsVulnerability to poverty was significantly lower among residents with rural health insurance than those without any health insurance coverage, and this difference was observed across age and income groups. These findings were consistently robust and significant after controlling for endogeneity, considering sample selectivity, and eliminating measurement bias in the core variables.ConclusionThe findings indicate that rural health insurance is an important tool for poverty alleviation. The current results could effectively reduce the economic vulnerability of rural households facing health risks, ensuring broader economic security. Moreover, these findings provide policy references for managing relative poverty in China.

The only constant is change: Stable vs. variable aspects of food approach bias relate differently to food craving and intake

The tendency to approach food faster than to avoid it (i.e., approach bias) is thought to facilitate food intake, particularly foods that conflict with one's dietary goals. However, this relationship has been difficult to demonstrate, which ties into an ongoing debate about whether such cognitive-behavioral biases represent stable traits or fluctuating states. We thus investigated the temporal fluctuations of food approach bias (1), its within-participant association with food craving (2) and intake (3), and the role of top-down control in this bias-intake association (4). The 76 participants completed an impulsivity questionnaire and performed a smartphone-based approach-avoidance task on nine days. Every day, they also reported their daily craving, intake, and dietary intentions for 12 personalized foods they wanted to eat less or more often over the study period. Approach bias varied considerably within individuals (1), and correlated in unexpected ways with food craving (2) and intake (3); this association of approach bias with intake was moderated by inter-individual differences (rather than day-to-day fluctuations) in dietary intentions and impulsivity (4). Results emphasize the need to re-conceptualize approach bias as comprising both state and trait components, and indicate that the more trait-like aspects of top-down control gate the relationship of approach bias with intake. The large day-to-day variation in approach bias may explain why single-session bias measures often do not predict distal outcomes like body weight. Furthermore, our results suggest that interventions targeting approach bias may be most effective for certain timepoints (high-risk situations) and individuals (those with weak dietary intentions).

The structured assessment of violence risk in youth demonstrates measurement invariance between Black and White justice-referred youths.

Identification and implementation of effective methods for reducing racial/ethnic bias and disparities in legal settings are paramount in the United States and other countries. One procedure originally thought to reduce bias in legal decisions is the use of risk assessment instruments, which is now being heavily scrutinized. Measurement invariance, a latent trait technique, is a robust method for assessing one form of bias. Measurement invariance involves determining whether risk items in an instrument appear to be functioning the same between racial or other groups. Thus, the present study examined measurement invariance of the Structured Assessment of Violence Risk in Youth (SAVRY) between non-Latino Black and White youths to examine racial bias. We expected the SAVRY to be invariant (lacking measurement bias) between Black and White youths. The sample included 687 Black and 361 White youths, and the study used a large, multistate data set of SAVRYs conducted by probation officers. We conducted measurement invariance testing in a series of hierarchical steps including testing configural and scalar invariance. The SAVRY demonstrated scalar invariance (equal thresholds for ratings from "low" to "moderate" and "moderate" to "high") for all items except one-community disorganization. The findings lend further credibility to the SAVRY, and the structured professional judgment approach, as a method to assess violence risk and case planning needs among youths involved in the legal system. These findings provide more confidence that significant differences in SAVRY risk level or items between Black and White youths are not based in measurement bias, with the exception of the community disorganization item. Potential fixes discussed include eliminating or deemphasizing this item in final risk level ratings. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Compensation of isotope ratio mismatch in double isotope dilution inductively coupled plasma mass spectrometry (ID-ICP/MS)

Abstract Exact-matching double isotope dilution inductively coupled plasma mass spectrometry (ID-ICP/MS) is widely used to characterize reference materials (RMs) in elemental analysis. In this technique, achieving exactly matching isotope ratios for the sample and calibration blends is regarded as an important prerequisite for obtaining accurate measurement results. However, meeting this condition requires multiple time-consuming iterative measurements. In the current study, an alternative approach that can avoid lengthy iterative procedures while maintaining the accuracy of the ID-ICP/MS results was successfully investigated. We examined the effects of an extensively wide range of inexact-matching isotope ratios (approximately 75 %–130 %) in double ID-ICP/MS for elements with a wide mass range. Our experimental study, using gravimetrically prepared samples of Ca, Cd, Cu, Fe, Hg, Mg, Ni, Pb, and Zn, demonstrated that, despite deliberately introducing mismatching of isotope ratios, the accuracy of the ID-ICP/MS results remained consistent with relative measurement bias of typically less than 0.5 %. The absence of a systematic bias due to deviations in the sample blend isotope ratios from the target ratios of the calibration blends revealed that the variability due to an isotope ratio mismatch was sufficiently compensated for. Furthermore, the expanded measurement uncertainties were sufficiently small with negligible variations observed across the different matching ratios. Typically, they were less than 1 %, except for Fe, Hg, Pb, and Zn which were less than 2 %. This assertion is also supported by theoretically calculated error magnification factors. Consequently, it is feasible to directly utilize the marginally estimated mass fraction of the analyte of interest without extensive iterative measurements. The findings of this study provide robust data for ID-ICP/MS, allowing to circumvent lengthy iterative procedures while maintaining the accuracy and precision of the measurement results, particularly in the characterization of reference materials for elemental analysis.

A Method for Compensating Hemoglobin Interference in Total Serum Bilirubin Measurement Using a Simple Two-Wavelength Reflectance Photometer.

Neonatal hyperbilirubinemia (NH) is a common condition in newborns, with elevated bilirubin levels potentially causing neurological damage or death. Accurate and timely measurements of total serum bilirubin are essential to prevent these outcomes. Direct spectrophotometry, a reliable method for measuring bilirubin, is particularly useful in constrained settings due to its potential for portable low-cost instrumentation. However, this method is susceptible to interference from hemoglobin, often present due to hemolysis. Typically, this interference is reduced using complex optical filters, reagents, multiple wavelengths, or combinations thereof, which increase costs and complexity while reducing usability. This study presents a hemoglobin compensation algorithm applied to a simple, portable, two-wavelength (465 and 590 nm) reflectance photometer designed to receive 30 µL of plasma or whole blood samples and perform the measurement without any reagents. Testing across five bilirubin and hemoglobin levels (4.96 to 28 mg/dL and 0.06 to 0.99 g/dL, respectively) demonstrated that the algorithm effectively reduces hemoglobin interference and overestimation errors. The overall root mean square error was reduced from 4.86 to 1.45 mg/dL, while the measurement bias decreased from -4.46 to -0.10 mg/dL. This substantial reduction in overestimation errors supports future clinical trials with neonatal blood samples.

Micro-mechanisms of digitalization-driven financing for renewable energy: Growing capital pools and shifting flows

Recent facts from China suggest that the advancement of digitalization is altering the market expectations regarding renewable energy. Limited studies have offered evidence encompassing the stock effect of digitalization that enhanced corporate financing and the flow effect that initiated speculative behavior. However, a comprehensive discourse remains insufficient. This paper investigates the synergetic effects of digitalization's stock and flow on renewable energy financing, employing the business data of all listed companies in China from 2003 to 2023. The results demonstrate that: (1) Digitalization's stock has expanded the potential fund pool for renewable energy financing, yet it is challenging to influence the flow of funds; digitalization's flow has triggered a flood of funds into the renewable energy industry, but this relies on the new investors attracted by the stock. (2) The synergetic effect governs the systematic influence of digitalization on renewable energy financing and mitigates the measurement bias when considering only a single effect. (3) We further contemplate the indirect effects of renewable energy market expansion, technological progress, and global energy market fluctuations, alleviating concerns regarding the omitted variable bias. The results of the differential regression and generalized method of moments also indicate the robustness of the conclusion.

Reliable measures of rest-activity rhythm fragmentation: how many days are needed?

BackgroundA more fragmented, less stable rest-activity rhythm (RAR) is emerging as a risk factor for health. Accelerometer devices are increasingly used to measure RAR fragmentation using metrics such as inter-daily stability (IS), intradaily variability (IV), transition probabilities (TP), self-similarity parameter (α), and activity balance index (ABI). These metrics were proposed in the context of long period of wear but, in real life, non-wear might introduce measurement bias. This study aims to determine the minimum number of valid days to obtain reliable fragmentation metrics.MethodsWrist-worn accelerometer data were drawn from the Whitehall accelerometer sub-study (age: 60 to 83 years) to simulate different non-wear patterns. Pseudo-simulated data with different numbers of valid days (one to seven), defined as < 1/3 of non-wear during both day and night periods, and with omission or imputation of non-wear periods were compared against complete data using intraclass correlation coefficient (ICC) and mean absolute percent error (MAPE).ResultsFive days with valid data (97.8% of participants) and omission of non-wear periods allowed an ICC ≥ 0.75 and MAPE ≤ 15%, acceptable cut points for reliability, for IS and ABI; this number was lower for TPs (two-three days), α and IV (four days). Overall, imputation of data did not provide better estimates. Findings were consistent across age and sex groups.ConclusionsThe number of days of wrist accelerometer data with at least 2/3 of wear time for both day and night periods varies from two (TPs) to five (IS, ABI) days for reliable RAR measures among older adults.

A Matter of Memory? Age-Invariant Relative Clause Disambiguation and Memory Interference in Older Adults.

Past research suggests that Working Memory plays a role in determining relative clause attachment bias. Disambiguation preferences may further depend on Processing Speed and explicit memory demands in linguistic tasks. Given that Working Memory and Processing Speed decline with age, older adults offer a way of investigating the factors underlying disambiguation preferences. Additionally, older adults might be subject to more severe similarity-based memory interference given their larger vocabularies and slower lexical access. Nevertheless, memory interference and sentence disambiguation have not been combined in studies on older adults before. We used a self-paced reading paradigm under memory load interference conditions. Older (n=30) and Younger (n=35) readers took part in the study online; reading times were recorded and measures of comprehension accuracy and load recall were collected. This setup allowed for the implicit measurement of attachment biases and memory interference effects interactively. Results show that similarity-based interference affected both age groups equally, but was more pronounced in NP2-biased structures, which took participants generally longer to read. Attachment preferences did not differ by group and were unaffected by Working Memory span. However, accuracy on recall prompts was predicted by Working Memory span in both groups. Findings of greater interference in syntactically dispreferred structures support unified processing models where parsing constraints naturally interact. The lack of age differences on our measures further aligns with research finding age-invariant implicit language processing.

Euclid preparation. LIII. LensMC, weak lensing cosmic shear measurement with forward modelling and Markov Chain Monte Carlo sampling

is a weak lensing shear measurement method developed for and Stage-IV surveys. It is based on forward modelling in order to deal with convolution by a point spread function (PSF) with comparable size to many galaxies, sampling the posterior distribution of galaxy parameters via Markov chain Monte Carlo, and marginalisation over nuisance parameters for each of the 1.5 billion galaxies observed by We quantified the scientific performance through high-fidelity images based on the Flagship simulations and emulation of the VIS images, realistic clustering with a mean surface number density of $ arcmin^ for galaxies, and $ arcmin^ for stars, and a diffraction-limited chromatic PSF with a full width at half maximum of $ $ and spatial variation across the field of view. measured objects with a density of $ arcmin^ in $4500 deg^2 $. The total shear bias was broken down into measurement (our main focus here) and selection effects (which will be addressed in future work). We found measurement multiplicative and additive biases of $m_1=(-3.6 $, $m_2=(-4.3 $, $c_1=(-1.78 $, and $c_2=(0.09 $; a large detection bias with a multiplicative component of $1.2 $ and an additive component of $-3 $; and a measurement PSF leakage of $ $ and $ $. When model bias is suppressed, the obtained measurement biases are close to requirement and largely dominated by undetected faint galaxies ($-5 $). Although significant, model bias will be straightforward to calibrate given its weak sensitivity on galaxy morphology parameters. is publicly available at

Physical understanding of a normally off p-GaN/AlGaN/GaN HEMT gate stack and a review of VTH measurement techniques

Abstract In this report a comprehensive review of the variations in threshold voltage (VTH) resulting from diverse VTH measurement bias conditions employed by leading manufacturers, as well as VTH extraction techniques is made. Notably, a standard deviation of 15% is observed in threshold voltage values due to variations in measurement bias conditions. This variation is attributed to the change in the lateral electic field conditions across gate and drain which occurs due to the change in bias conditions. Additionally, a simplified physical interpretation of the gate stack in p-GaN gate normally-off AlGaN/GaN on Si HEMTs is made. The formation of the two-dimensional electron gas (2DEG), the charge balance within the pGaN/AlGaN/GaN gate stack, and an analytical expression for threshold voltage are examined. Furthermore, various trapping mechanisms within the gate stack are reviewed to comprehend the dynamic conditions potentially contributing to threshold voltage instability during nominal operation.&amp;#xD;

Continuous planning for inertial-aided systems

Inertial-aided systems require continuous motion excitation among other reasons to characterize the measurement biases that will enable accurate integration required for localization frameworks. This paper proposes the use of informative path planning to find the best trajectory for minimizing the uncertainty of IMU biases and an adaptive traces method to guide the planner towards trajectories that aid convergence. The key contribution is a novel regression method based on Gaussian Process (GP) to enforce continuity and differentiability between waypoints from a variant of the RRT∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {RRT}^*$$\\end{document} planning algorithm. We employ linear operators applied to the GP kernel function to infer not only continuous position trajectories, but also velocities and accelerations. The use of linear functionals enable velocity and acceleration constraints given by the IMU measurements to be imposed on the position GP model. The results from both simulation and real-world experiments show that planning for IMU bias convergence helps minimize localization errors in state estimation frameworks.

Quaternion-based fixed-time tracking control for an autonomous underwater vehicle with consideration of measurement bias

This article investigates trajectory and attitude tracking control problem of a 6-degree of freedom (DOF) autonomous underwater vehicle (AUV) subject to measurement bias and external disturbance. First, the model dynamics of rotational channels are established by unit-quaternion, which possesses simplicity and broader applicability compared to the Euler angle such that the maneuver signal could be uniquely determined. Meanwhile, by introducing constraint of the logarithm function and initial value, the unwinding phenomenon existing in rotation motion can be avoided tactfully. Considering the high requirement for sensor accuracy, the resulting measurement bias in position and velocity channels, making AUV into a mismatched system and bring the uncertain term in the process of controller design. Therefore, the echo state network (ESN) with online updates performance is applicable to approximate uncertain term simultaneously generated by measurement bias and unknown external disturbance. Then, by incorporating composite hyperbolic tangent function, the quasi-fast terminal sliding mode (QTSM) surface is constructed to realize the fixed-time convergence peculiarity of the AUV tracking system. Compared with the existing methods, the proposed algorithm can regulate artificially the stable schedule of the AUV tracking system and possess the capacity of bias tolerance and anti-disturbance. Finally, simulation results verify the validity and feasibility of the developed control algorithm.