Bias Dependence Research Articles

A comprehensive assessment of current methods for measuring metacognition

Abstract One of the most important aspects of research on metacognition is the measurement of metacognitive ability. However, the properties of existing measures of metacognition have been mostly assumed rather than empirically established. Here I perform a comprehensive empirical assessment of 17 measures of metacognition. First, I develop a method of determining the validity and precision of a measure of metacognition and find that all 17 measures are valid and most show similar levels of precision. Second, I examine how measures of metacognition depend on task performance, response bias, and metacognitive bias, finding only weak dependences on response and metacognitive bias but many strong dependencies on task performance. Third, I find that all measures have very high split-half reliabilities, but most have poor test-retest reliabilities. This comprehensive assessment paints a complex picture: no measure of metacognition is perfect and different measures may be preferable in different experimental contexts.

Quantitative theoretical analysis of the electrostatic force between a metallic tip and semiconductor surface in Kelvin probe force microscopy

Theoretical analysis of the electrostatic force between a metallic tip and semiconductor surface in Kelvin probe force microscopy (KPFM) measurements has been challenging due to the complexity introduced by tip-induced band bending (TIBB). In this study, we present a method for numerically computing the electrostatic forces in a fully three-dimensional (3D) configuration. Our calculations on a system composed of a metallic tip and GaAs(110) surface revealed deviations from parabolic behavior in the bias dependence of the electrostatic force, which is consistent with previously reported experimental results. In addition, we show that the tip radii estimated from curve fitting of the theory to experimental data provide reasonable values, consistent with the shapes of tip apex observed using scanning electron microscopy. The 3D simulation, which accounted for the influence of TIBB, enables a detailed analysis of the physics involved in KPFM measurements of semiconductor samples, thereby contributing to the development of more accurate measurement and analytical methods.&#xD.

Glacial Erosion Rates Since the Last Glacial Maximum for the Former Argentino Glacier and Present‐Day Upsala Glacier, Patagonia

AbstractRecovering the patterns of glacial erosion over time is key to understanding feedbacks between climate and tectonic processes. Glacial erosion rates have been shown to systematically increase worldwide toward the present since the late Cenozoic, a behavior interpreted as the response of glaciers to a cooling and increasingly variable climate. However, the validity of this signal has been questioned, and suggested to be affected by the incompleteness of the sedimentary record, which can introduce a time dependent bias in the time averaged rates. In this study, we present new glacial erosion rates estimated from sediment accumulations in Lago Argentino, Patagonia, a proglacial basin with a nearly complete preserved sedimentary record. The erosion rates are estimated through the past 20,000 years and averaged over time intervals ranging from sub‐decadal to millennial, allowing us to explore erosion rate variability through time and within a glacial cycle. The data show that erosion rates have varied substantially, from 0.43 0.12 to 82.38 17.58 mm/yr, with no systematic increase (or decrease) through time. Rather, erosion occurs during discrete, intense events separated by times of quiescence. In addition, we find that glacial erosion rates have comparable magnitudes when averaged over similar time intervals. Our data show a power‐law increase in glacial erosion rates with decreasing averaging time interval, consistent with other observations globally. Given our observed intermittent character of glacial erosion, we attribute this increase to a time averaging bias, rather than to an escalation in magnitude of erosional pulses toward the present.

Implementing Parameterizations of Sub‐Pixel Terrain Long‐Wave Radiative Effect for FY‐4A/AGRI Infrared Data Assimilation Over Land Based on the Community Radiative Transfer Model

AbstractThe sub‐pixel terrain long‐wave radiative effect (STLRE) plays an important role in the satellite surface‐sensitive infrared brightness temperature (TB) simulation over rugged areas, however, it is absent in current radiative transfer models. This study incorporates a STLRE scheme in the Community Radiative Transfer Model (CRTM) for the FY‐4A/Advanced Geosynchronous Radiation Imager (AGRI). The total surface downwelling long‐wave radiance (SDLR) over rugged areas at sub‐pixel is composed of the radiance from the overlying atmosphere under plane‐parallel radiation condition and the radiance emitted from surrounding terrains, weighted by the sky view factor (SKV). Based on the homogenous assumption, a STLRE scheme is established through constructing terrain correction factors at AGRI pixel scale. The ExpCTL/ExpTOPO experiments with the CRTM adopting the plane‐parallel scheme/STLRE scheme are conducted to evaluate the simulations of AGRI clear‐sky TB over the rugged areas. Results show that considering the STLRE can significantly reduce the orography dependent simulation biases in the plane‐parallel scheme. The reductions of biases for the AGRI channel 11–13 regionally averaged over the rugged areas are 64.2%, 72.7% and 67.6%, respectively. Stable correction performance is found at different times of the day. Meanwhile, the corrections of SDLR are more obvious in winter than in summer, and in barren condition than in the other land cover types. This is theoretically attributed to the land‐air temperature difference and the land surface emissivity, respectively. This pilot study improves the observation operator for infrared TB data assimilation over complex terrain and exhibits broad promotion and application value.

Sensory History Drives Adaptive Neural Geometry in LP/Pulvinar-Prefrontal Cortex Circuits.

Prior expectations guide attention and support perceptual filtering for efficient processing during decision-making. Here we show that during a visual discrimination task, mice adaptively use prior stimulus history to guide ongoing choices by estimating differences in evidence between consecutive trials (| Δ Dir |). The thalamic lateral posterior (LP)/pulvinar nucleus provides robust inputs to the Anterior Cingulate Cortex (ACC), which has been implicated in selective attention and predictive processing, but the function of the LP-ACC projection is unknown. We found that optogenetic manipulations of LP-ACC axons disrupted animals' ability to effectively estimate and use information across stimulus history, leading to | Δ Dir |-dependent ipsilateral biases. Two-photon calcium imaging of LP-ACC axons revealed an engagement-dependent low-dimensional organization of stimuli along a curved manifold. This representation was scaled by | Δ Dir | in a manner that emphasized greater deviations from prior evidence. Thus, our work identifies the LP-ACC pathway as essential for selecting and evaluating stimuli relative to prior evidence to guide decisions.

Comparing the Efficacy of Matrix Therapy, Transcranial Magnetic Stimulation, and Cognitive Rehabilitation in Attention Bias Modification and Craving Reduction in Stimulant Drug Users

Introduction: Previous studies have shown that Matrix, repetitive transcranial magnetic stimulation (rTMS), and cognitive modification treatments could lead to numerous psychological improvements in patients suffering from substance use disorders. Previous research has shown that other therapeutic interventions could be useful in managing stimulant abuse in addition to Matrix treatment The present study aimed at comparison of the effectiveness of matrix therapy, transcranial magnetic stimulation and cognitive rehabilitation treatments in attention bias modification and craving reduction in amphetamine drug users. Methods: This study was quasi-experimental with pretest-posttest and three-month follow-up. Forty subjects taking amphetamine were selected by convenient sampling method and were randomly divided into three groups, including the matrix therapy, cognitive rehabilitation and rTMS as intervention groups and control groups (10 subjects in each group). The matrix group received 24 treatment sessions, 3 sessions per week and cognitive rehabilitation group recivied 15 treatment sessions (3 sessions per week). The group with rTMS treatment participated in a total of 10 sessions every other day. Questionnaires and dot-Probe tasks were performed as the cognitive software before and after the therapeutic interventions and one month after the interventions as a follow-up test. Results: The results showed that the effect of time on craving assessment in three stages was significant in all the study's four groups. In the experimental groups of Matrix, rTMS, and cognitive rehabilitation, the effect of time on the severity of addiction dependence and attentional bias was significantly different in three stages. In the control group, the effect of time in three stages of assessment of addiction severity and attention bias was not significant. Also, there was a significant decrease in the mean of craving in Matrix, rTMS, and cognitive rehabilitation groups from pre-treatment to post-treatment and from pre-treatment to follow-up stages. The mean addiction severity was significantly decreased from pre-treatment to post-treatment and from pre-treatment to follow-up stage in the Matrix, rTMS, and cognitive rehabilitation groups. Conclusion: The current study's findings indicated that all three interventions effectively reduced amphetamine craving and attentional bias. All three approaches produced positive therapeutic outcomes.

Estimation bias and serial dependence in speed perception

Studies have found that feature estimates are systematically compressed towards the distribution center, showing a central tendency. Additionally, the estimate of current features is affected by the previously seen feature, showing serial dependence or adaptation effect. However, these all remain unclear in the speed estimation. To address this question, we asked participants to estimate the speed of moving Gabor patches. In Experiment 1, speeds were selected from three uniform distributions with different lower and upper boundaries (i.e., slow, moderate, and fast ranges). In Experiment 2, speeds were arranged in an increasing, uniform, or decreasing distribution. The boundaries of three distributions were the same. The results found that speed estimates were systematically compressed towards the center of the uniform distribution center, showing a central tendency, and its size increased with the range boundaries. However, in the decreasing and increasing distributions, aside from central tendency, the speed estimates were also showed a bias away from the heavy tail of the distributions. Moreover, there was an attractive serial dependence that was not affected by the speed range. In summary, the current study, along with previous studies that reveal a slow-speed bias, comprehensively reveals various estimation biases in speed perception.

Imaging Quantum Interference in a Monolayer Kitaev Quantum Spin Liquid Candidate

Single atomic defects are prominent windows to look into host quantum states because collective responses from the host states emerge as localized states around the defects. Friedel oscillations and Kondo clouds in Fermi liquids are quintessential examples. However, the situation is quite different for quantum spin liquid (QSL), an exotic state of matter with fractionalized quasiparticles and topological order arising from a profound impact of quantum entanglement. Elucidating the underlying local electronic property has been challenging due to the charge neutrality of fractionalized quasiparticles and the insulating nature of QSLs. Here, using spectroscopic-imaging scanning tunneling microscopy, we report atomically resolved images of monolayer α−RuCl3, the most promising Kitaev QSL candidate, on metallic substrates. We find quantum interference in the insulator manifesting as incommensurate and decaying spatial oscillations of the local density of states around defects with a characteristic bias dependence. The oscillation differs from any known spatial structures in its nature and does not exist in other Mott insulators, implying it is an exotic oscillation involved with excitations unique to α−RuCl3. Numerical simulations suggest that the observed oscillation can be reproduced by assuming that itinerant Majorana fermions of Kitaev QSL are scattered across the Majorana Fermi surface. The oscillation provides a new approach to exploring Kitaev QSLs through the local response against defects like Friedel oscillations in metals. Published by the American Physical Society 2024

Significant contributions of the Higgs mode and impurity-scattering self-energy corrections to the low-frequency complex conductivity in dc-biased superconducting devices

We investigate the complex conductivity of superconductors under a direct-current (dc) bias based on the well-established Keldysh-Eilenberger formalism of nonequilibrium superconductivity. This robust framework allows us to account for the Higgs mode and impurity-scattering self-energy corrections, which are now known to significantly impact the complex conductivity under a bias dc, especially near the resonance frequency of the Higgs mode. The purpose of this paper is to explore the effects of these contributions on the low-frequency complex conductivity relevant to superconducting device technologies. We begin by nonperturbatively calculating the equilibrium Green’s functions under a bias dc, followed by an analysis of the time-dependent perturbative components. This approach enables us to derive the complex conductivity formula for superconductors ranging from clean to dirty limits, applicable to any bias dc strength. We validate our theoretical approach by reproducing known results and experimentally observed features, such as the characteristic peak in σ1 and the dip in σ2 attributed to the Higgs mode. Our calculations reveal that the Higgs mode and impurity-scattering self-energy corrections significantly affect the complex conductivity even at low frequencies (ℏω≪Δ), relevant to superconducting device technologies. Specifically, we find that the real part of the low-frequency complex conductivity, σ1, exhibits a bias-dependent reduction up to ℏω∼0.1, a much higher frequency than previously considered. This finding allows for the suppression of dissipation in devices by tuning the bias dc. Additionally, through the calculation of the imaginary part of the complex conductivity, σ2, we evaluate the bias-dependent kinetic inductance for superconductors ranging from clean to dirty limits. The bias dependence becomes stronger as the mean free path decreases. Our dirty-limit results coincide with previous studies based on the oscillating superfluid density (the so-called slow experiment) scenario. This widely used scenario can be understood as a phenomenological implementation of the Higgs mode into the kinetic inductance calculation, now justified by our calculation based on the robust theory of nonequilibrium superconductivity, which microscopically treats the Higgs-mode contribution. These results highlight the importance of considering the Higgs mode and impurity-scattering self-energy corrections in the design and optimization of superconducting devices under a bias dc. Published by the American Physical Society 2024

Comparing Cost and Acceptability of Two Instruments to Measure Instrumental Activities of Daily Living in Older People in Chile

Introduction: Population aging and increasing long-term care needs call for designing and implementing better tools for assessing functional ability. In Chile, the Lawton and Brody (L&B) scale is used for identifying limitations with instrumental activities. This study compared the costs and acceptability of the L&B with a new instrument to measure instrumental activities of daily living (IADL): the Instrument for the Assessment of Functionality Stages (Instrumento de Evaluación de Estadios de Funcionalidad; IDEEF). Methods: Phone surveys were carried out to apply the L&B and the IDEEF to a sample of 200 older people (60+) participating in public programs for older people in the Metropolitan Region, Chile. Besides the items assessed by each scale, the survey captured completion times and included a short questionnaire on acceptability, data that allowed comparisons between instruments. Results: On average, the L&B takes around 4 min to be applied; the completion times for the IDEEF are 4 times longer. However, the IDEEF performs better in terms of acceptability and has neither gender bias nor dependency bias. Conclusion: Both instruments have pros and cons, but the IDEEF appears as a feasible alternative to the L&B to improve the assessment of IADL in the country.

The dependence of halo bias on the protohalo shape alignment with the initial tidal field

We present a numerical evidence supporting the primordial origin of secondary halo bias even on the galactic mass scale.Analyzing the data from the TNG 300-1 simulations, we investigate the dependence of halo bias on the degree of misalignment between the protohalo inertia andinitial tidal tensors, τ, measured at redshift, z i =127. From the TNG 300-1 galactic halos in logarithmic mass range of 10.5 < m ≡ log[M/(h -1 M ⊙)] ≤ 13identified at z=0, 0.5 and 1, a clear signal of τ bias is detected. For the case that τ is measured from the initial tidal field smoothed on the scale ofRf /(h -1Mpc) ≲ 1, the halo τ bias is found to be very similar in its tendency and amplitude to the spin bias at all of the three redshifts,if the effects of backsplash halos are properly eliminated.For the case of Rf /(h -1Mpc) = 2, the τ bias at z=1 turns out to behave like the age bias, diminishing rapidly in the range of m > 12.At z=0 and 0.5, however, the τ and age bias factors show large differences in their overall strengths, which is attributed to the dominant nonlinear effectsthat undermine the former but enhance the latter.Given these numerical results along with the previous finding [1] that τ shares a large amount of mutual information with the formation epochs andspin parameters of galactic halos, it is concluded that the origins of halo age and spin bias must be closely linked with the primordial factor, τ, and thatthe difference in the tendency between the two bias factors on the galactic mass scale reflects the multi-scale influence of τ on the halo secondary properties.

Impact of assembly bias on clustering plus weak lensing cosmological analysis

Context. Empirical models of galaxy-halo connection such as the halo occupation distribution (HOD) model have been widely used over the past decades to intensively test perturbative models on quasi-linear scales. However, these models fail to reproduce the galaxygalaxy lensing signal on non-linear scales, over-predicting the observed signal by up to 40%. Aims. With ongoing Stage-IV galaxy surveys such as DESI and Euclid that will measure cosmological parameters at sub-percent precision, it is now crucial to precisely model the galaxy-halo connection in order to accurately estimate the theoretical uncertainties of perturbative models. Methods. This paper compares a standard HOD (based on halo mass only) to an extended HOD that incorporates as additional features galaxy assembly bias and local environmental dependencies on halo occupation. These models were calibrated against the observed clustering and galaxy-galaxy lensing signal of eBOSS luminous red galaxies and emission line galaxies in the range 0.6 &lt; z &lt; 1.1. We performed a combined clustering-lensing cosmological analysis on the simulated galaxy samples of both HODs to quantify the systematic budget of perturbative models. Results. By considering not only the mass of the dark matter halos but also these secondary properties, the extended HOD offers a more comprehensive understanding of the connection between galaxies and their surroundings. In particular, we found that the luminous red galaxies preferentially occupy denser and more anisotropic environments. Our results highlight the importance of considering environmental factors in empirical models with an extended HOD that reproduces the observed signal within 20% on scales below 10 h−1 Mpc. Our cosmological analysis reveals that our perturbative model yields similar constraints regardless of the galaxy population, with a better goodness of fit for the extended HOD. These results suggest that the extended HOD should be used to quantify modelling systematics. This extended framework should also prove useful for forward modelling techniques.

Dual-Stream Feature Collaboration Perception Network for Salient Object Detection in Remote Sensing Images

As the core technology of artificial intelligence, salient object detection (SOD) is an important approach to improve the analysis efficiency of remote sensing images by intelligently identifying key areas in images. However, existing methods that rely on a single strategy, convolution or Transformer, exhibit certain limitations in complex remote sensing scenarios. Therefore, we developed a Dual-Stream Feature Collaboration Perception Network (DCPNet) to enable the collaborative work and feature complementation of Transformer and CNN. First, we adopted a dual-branch feature extractor with strong local bias and long-range dependence characteristics to perform multi-scale feature extraction from remote sensing images. Then, we presented a Multi-path Complementary-aware Interaction Module (MCIM) to refine and fuse the feature representations of salient targets from the global and local branches, achieving fine-grained fusion and interactive alignment of dual-branch features. Finally, we proposed a Feature Weighting Balance Module (FWBM) to balance global and local features, preventing the model from overemphasizing global information at the expense of local details or from inadequately mining global cues due to excessive focus on local information. Extensive experiments on the EORSSD and ORSSD datasets demonstrated that DCPNet outperformed the current 19 state-of-the-art methods.

Tailored accelerometer calibration by POD for thermospheric density retrieval with GRACE and GRACE-FO

The density of the upper atmosphere can be determined by orbit and accelerometer data from low Earth orbit satellites as insitu measurements along the orbit. One main challenge therein is the estimation of physical accelerometer calibration parameters, meaning that these parameters should not absorb other effects and model deficiencies in the Precise Orbit Determination (POD) process. The accelerometers of all geodetic satellites like GRACE and GRACE-FO are affected by time dependent bias and scale factors. Therefore a calibration of the data is indispensable.A dynamic POD based physical accelerometer calibration is developed for the complete GRACE and GRACE-FO missions. We investigate different parametrization strategies and utilize different observation data, as the accurate inter-satellite ranging additionally to GPS orbit data. For the estimation parameters we distinguish between offset and scale, furthermore, cross-track and radial directions are significantly less sensitive than along-track and require a different evaluation. For the offset, constant and time dependent parameters are investigated. Furthermore, a continuous offset calibration over arc boundaries is implemented and tested. The sensitivity of the scale factor is lower, although, in contrast to the offset, it increases with higher total accelerations. This means that it needs to be estimated over longer time periods. We investigate periods between three hours and one month as well as results from Gravity Field Recovery (GFR). Monthly scale factors give valuable results, at least for x-axis and when the Solar activity is not very low. Nevertheless, we also estimate weighted constant scale factors from the monthly results and use these in a subsequent POD, giving more realistic offset results for most periods and cross-track and radial directions.From the used background models in the POD, Earth’s gravitational model has a noticeable influence on the estimated calibration parameters, especially the scale factors. We utilized several different models. Results with monthly ITSG solutions are distinctly better than the ones with the time dependent GOCO06s model.We show that the validation with usual metrics, like post-fit POD residuals, is not able to reflect the quality of the different estimated calibration parameters. For a quantitative validation we introduce an approach based on the modeled non-gravitational accelerations. Therefore, the uncertainty of the models is evaluated first. The influence of main error sources in the models is assessed and propagated to the results.We compare our scale parameters to available references and the complete calibration to TU Delft’s latest results. Finally we show the effect of different calibration options on the retrieved density.The estimated calibration parameters and non-gravitational accelerations for the whole GRACE and GRACE-FO missions are available on our data server www.zarm.uni-bremen.de/zarm_daten.

Opposite-Direction Spatial Working Memory Biases in People With Schizophrenia and Healthy Control Participants

BackgroundPeople with schizophrenia (PSZ) show impaired accuracy in spatial working memory (sWM), which is thought to reflect abnormalities in the sustained firing of feature selective neurons that are critical for successful encoding and maintenance processes. Recent research has documented a new source of variance in the accuracy of sWM: In healthy adults, sWM representations are unconsciously biased by previous trials such that current-trial responses are attracted to previous-trial responses (serial dependence). This opens a new window to examine how schizophrenia impacts both the sustained neural firing representing the current-trial target and the longer-term synaptic plasticity that stores previous-trial information. MethodsWe examined response accuracy in a single-item sWM test with delay intervals of 0, 2, 4, or 8 seconds in 41 PSZ and 32 demographically similar healthy control participants. Our main dependent variable was the bias index, which quantifies the extent to which the current-trial responses were biased toward or away from the previous-trial target. ResultsPSZ showed opposite-direction serial dependence bias effects: Healthy control participants showed an attractive bias that increased over increasing delays whereas PSZ showed a repulsion bias that increased over delays. In PSZ, the magnitude of the repulsion bias negatively correlated with broad measures of cognitive ability and WM capacity. ConclusionsPSZ show opposite-direction effects of previous trials on WM. Such qualitatively distinct differences in performance are extremely rare in psychopathology and may index a fundamental alteration in neural processing that could serve as a valuable biomarker for pathophysiology and treatment development research.

Charge Carrier Capture by Prominent Defect Centers in 4H-SiC

The knowledge of capture properties of electrically active defects is of primary importance as it helps to understand which deep states are effective in controlling the excess free carriers’ lifetime. Combining DLTS capture experiments with thermal emission measurements enables an overall thermodynamic description of deep states, thus making it possible to characterize recombination centers in semiconductor-based devices. In the present study, junction DLTS capture rate measurements were employed to extract the true capture cross-sections (inversely proportional to the carrier lifetime) and capture energy barriers for the main lifetime limiting defects in 4H-SiC (silicon carbide). A peculiar forward bias dependence of the capture parameters was observed for the shallow boron (B) hole trap. Capture rate measurements on the deep boron (D-center) trap also evidenced the presence of two capture mechanisms, thus allowing discrimination of D1 and D2 deep states within the D-center DLTS peak. The results were combined with activation energies and apparent capture cross-sections to obtain the free energy (ΔG) of electronic activation for the analysed deep states.

Elevation-dependent biases of raw and bias-adjusted EURO-CORDEX regional climate models in the European Alps

Data from the EURO-CORDEX ensemble of regional climate model simulations and the CORDEX-Adjust dataset were evaluated over the European Alps using multiple gridded observational datasets. Biases, which are here defined as the difference between models and observations, were assessed as a function of the elevation for different climate indices that span average and extreme conditions. Moreover, we assessed the impact of different observational datasets on the evaluation, including E-OBS, APGD, and high-resolution national datasets. Furthermore, we assessed the bi-variate dependency of temperature and precipitation biases, their temporal evolution, and the impact of different bias adjustment methods and bias adjustment reference datasets. Biases in seasonal temperature, seasonal precipitation, and wet-day frequency were found to increase with elevation. Differences in temporal trends between RCMs and observations caused a temporal dependency of biases, which could be removed by detrending both observations and RCMs. The choice of the reference observation datasets used for bias adjustment turned out to be more relevant than the choice of the bias adjustment method itself. Consequently, climate change assessments in mountain regions need to pay particular attention to the choice of observational dataset and, furthermore, to the elevation dependence of biases and the increasing observational uncertainty with elevation in order to provide robust information on future climate.

Parent decisional regret regarding neonatal circumcision in an American outpatient pediatric urology clinic

Requests for circumcision revision are common in our American pediatric urology clinic. As parents are the surrogate decision maker for their child, there are several influences that can impact a parent's decision for or against circumcision. We sought to assess parents' regret regarding their child's circumcision status and to correlate regret to factors that might have affected the original decision. From March 2023 to January 2024, we surveyed parents who brought their male child to our office for any reason, independent of circumcision status. The questionnaire was two-fold: a validated Decisional Regret Scale (DRS) (0-100 where higher scores=higher regret) and our questions regarding their decision-making process and outcome. Regret scores served as a function of each of the independent decision making and outcome variables. Overall, decisional regret scores from both uncircumcised and circumcised parent groups were positively skewed with a median 0, mean 22, and ranged from 0 to 75. For those circumcised (n=91), the median regret score was 0 (IQR 0-25). For those uncircumcised (n=28), median regret score was 0 (IQR 0-24). Overall, 55% of both groups reported no regret (DRS=0), 24% had low-mild regret (DRS 5-25), and 21% yielded moderate-strong regret (DRS 30-100). Parents who felt they made an informed decision or were counseled by any physician had lower regret scores. Parents who presented for issues related to their child's uncircumcised or circumcised penis (DRS score 37.5 and 25 respectively) had higher regret scores. We found that a large portion of parents expressed no regret regarding their decision to have or not have their child circumcised (55%). There also was no difference in median regret scores between parent groups. However, a significant portion of parents did express moderate-strong regret (21%) and several influential factors were correlated with regret scores. These factors included informed decision making, physician counseling, appearance satisfaction, and problems related to their child's circumcised or uncircumcised penis. These factors are supported by other literature using the DRS and population studies. The limitations of our study included the limited recruitment of participants and potential time dependent bias of responses. One in five parents of both circumcised and uncircumcised boys expressed moderate to strong regret regarding their decision about neonatal circumcision in our pediatric urology clinic. Our data suggests that ensuring parents have sufficient counseling prior to a decision regarding neonatal circumcision is important.

Effects of a Spike-Annealed HfO2 Gate Dielectric Layer on the On-Resistance and Interface Quality of AlGaN/GaN High-Electron-Mobility Transistors

Various high-k dielectrics have been proposed for AlGaN/GaN MOSHEMTs for gate leakage and drain-current collapse suppression. Hafnium oxide (HfO2) is particularly interesting because of its large bandgap, high dielectric constant, and ferroelectricity under specific phase and doping conditions. However, defects and surface scattering caused by HfO2 dissimilarity and degraded HfO2/GaN interface quality still leave the challenge of reducing the SS and Ron. In this study, we investigated the effects of the first spike-annealed HfO2 (6 nm) layer, compared with the conventional ALD-HfO2 (6 nm) layer in the HfO2 bilayer gate dielectric structure on AlGaN/GaN HEMTs. Both devices exhibit negligible hysteresis and near-ideal (~60 mV/dec) subthreshold slopes of more than three orders of magnitude. The device with the first annealed HfO2 layer exhibited a reduced Ron with notably less gate bias dependency and enhanced output current. On the other hand, the capacitance–voltage and conductance methods revealed that the border and interface trap densities of the device were inferior to those of the conventional HfO2 layer. The trade-off between enhanced electrical performance and oxide traps is discussed based on these results.

Evidence of contact-induced variability in industrially-fabricated highly-scaled MoS2 FETs

Evidence of microscopic inhomogeneities of the side source/drain contacts in 300 mm wafer integrated MoS2 field-effect transistors is presented. In particular, the presence of a limited number of low Schottky barrier spots through which channel carriers are predominantly injected is demonstrated by the dramatic current changes induced by individual charge traps located near the source contact. Two distinct types of “contact-impacting traps” are identified. Type-1 trap is adjacent to the contact interface and exchanges carriers with the metal. Its impact is only observable when the adjacent contact is the reverse-biased FET source and limits the channel current. Type-2 trap is located in the AlOx gate oxide interlayer, near the source contact, and exchanges carriers with the channel. Its capture/emission time constants exhibit both a gate and drain bias dependence due to the high sensitivity of the contact regions to the applied lateral and vertical fields. Unlike typical channel-impacting oxide traps, both types of reported defects affect the Schottky barrier height and width rather than the threshold voltage and result in giant random telegraph noise (RTN). These observations indicate that the contact quality and geometry play a fundamental role in the ultimate scaling of 2D FETs.