Qualitative Errors Research Articles

Large time solution for collisional breakage model: Laplace transformation based accelerated homotopy perturbation method

The behavior of several particulate processes, such as cell interaction, blood clotting, bubble formation, grain breakage, and cheese formation from milk, have been studied using coagulation and fragmentation models (Fogelson and Guy, 2008 [1]; Pazmiño et al., 2022 [2]; Chen et al., [3]). Various studies utilize the linear fragmentation model to simplify the underlying physics. However, in real-life scenarios, particles form due to the collision of two particles, leading to a non-linear collisional breakage model. Unfortunately, the collisional breakage model is less explored due to its complex behavior. While analytical solutions are difficult to compute and are still missing in the literature, this article proposes an approximate solution for the model using the Laplace-based accelerated homotopy perturbation method. Further, coupling with Padé approximant, the accuracy of the solution is extended for the longer time. Considering various physically relevant kernels, the approximate series solutions are compared with the well known finite-volume solutions to measure the accuracy in terms of qualitative and quantitative errors. The article also encompasses theoretical convergence analysis and error estimations to enhance comprehension of the proposed formulation.

Quantifying a common inconsistency in RANS-VoF modeling of water and oil core annular flow

Current trends in modeling CAF of oil and water combine the interface capturing methodology of VoF with the computational savings of a RANS approach. As demonstrated mathematically, this results in an inconsistency in the overall RANS-VoF treatment and incurs a number of omissions in the solution of oil fraction advection and momentum. To quantify these inconsistencies, five CAF cases with increasing Rew are considered and solved via DNS. Symptoms of the inconsistencies include qualitative errors in the prediction of the flow behavior in the entrance and fully-developed regions, as well as in the transition between these two regions. From a momentum perspective, the more troubling issue is the absence of unclosed terms resulting from fluctuating viscous and surface tension forces in the RANS equations. For momentum advection, terms associated with fluctuating density can be safely ignored due to the similar magnitude between oil and water density.

Influence of the rigid water column assumption on hydrodynamic system stability

When analyzing the hydraulic vibration stability of hydrodynamic systems, a real elastic water column (EWC) is often simplified as a rigid water column (RWC) to derive theoretical stability criteria. This method is believed to yield results that deviate quantitatively from reality without causing qualitative errors. To examine this approach, this study first established a reservoir-pipe-valve-turbine system. Next, a theoretical stability criterion based on the RWC assumption was derived. Finally, the theoretical stability criterion of the real EWC (which was proven using the method of characteristics) was proposed to test the correctness of the RWC assumption, both numerically and theoretically. Results indicated discrepancies between RWC-based predictions and EWC time-domain outcomes, lacking consistent similarities. Specifically, in some cases, the RWC formula indicated instability, while the EWC theoretical criterion and numerical verification suggested stability. In other cases, the RWC formula indicated stability, while the EWC theoretical criterion and numerical verification suggested instability. Meanwhile, there were also cases where both the RWC formula and EWC theoretical criterion yielded consistent results. As the RWC assumption disregards water-hammer wave propagation and hydrodynamic system reflection effects, the validity of its conclusion is uncertain. Hence, when the RWC-based system stability contradicts the EWC theoretical criterion, the latter should guide system design decisions.

Impact of a Medication Reconciliation Improvement Package on Adherence to Medication Reconciliation Among Internal Medicine Physicians: A Quality Improvement Project in a Lower-Middle Income Country.

Background: Medication reconciliation is one of the best measures to prevent medication-related errors at the time of admission and discharge of patients. We conducted a quasi-experimental study to evaluate the impact of a Medication reconciliation improvement package (intervention) on adherence to medication reconciliation at the time of admission in Department of Internal Medicine. The study included all adult patients admitted to internal medicine from August 2019 to December 2020. Pre-intervention data on adherence to medication reconciliation was less than 50%. The study involved creation of a quality improvement team to conduct a root-cause analysis which identified the need to target physician related issues and hence drafted a medication reconciliation improvement package which included meetings with physicians on the internal medicine floor, dedicated WhatsApp groups for repeated reminders, and appreciation messages for timely adherence. We used the Chi Square test to check the association between adherence to medication reconciliation and physicians and acuity level. Findings: We included 7914 records of patients, in which 4471 participants (56.4%) were from pre-intervention phase and 3443 (43.5%) were from intervention groups. The overall adherence to medication reconciliation was 54.3% (4297/7914). Adherence of medication reconciliation increased from 44.4% (1983/4471) in the pre-intervention phase to 67.2% (2314/3443) in the intervention phase (P < .001). Improvement was observed in adherence of medication reconciliation done by residents and in low acuity areas (P < .005). Conclusion: The Medical reconciliation improvement package is a simple low-cost intervention that resulted in improvement in adherence to medication reconciliation but needs further studies to assess its sustainability. However, it awaits to be seen if the same improvement can also be replicated to qualitative medication errors and clinical outcomes respectively.

Electrokinetic index: A new metric for advanced characterization of membranes with various geometries

Electrokinetic measurements to determine the electrical properties (zeta potential) of membrane surfaces have become increasingly popular in the toolbox of characterization techniques. However, it has been established in the literature that parasitic phenomena such as electrokinetic leakage can hamper data interpretation, leading to not only quantitative but also qualitative errors in membrane zeta potential determination. To date, the only method for highlighting and accounting for electrokinetic leakage is limited to flat-sheet membranes. In this letter, we propose an alternative method that is much less time-consuming and applicable to all membrane geometries. This method is based on the determination of the electrokinetic index, which we define as the ratio of the apparent zeta potentials determined from single measurements of the streaming current and streaming potential coefficients. We show that variation in the electrokinetic index reflects modifications occurring within the membrane matrix (in addition to surface properties alteration). The chemical degradation of polyethersulfone (PES)-based flat-sheet and hollow-fiber membranes is used as a proof of concept, but the proposed approach is readily transposable to other problems of practical interest, such as e.g. membrane fouling. This work also paves the way for the development of a new type of electrokinetic sensors for on-line monitoring of membrane operations.

Reworking the Tao-Mo exchange-correlation functional. II. De-orbitalization.

In Paper I [H. Francisco, A. C. Cancio, and S. B. Trickey, J. Chem. Phys. 159, 214102 (2023)], we gave a regularization of the Tao-Mo exchange functional that removes the order-of-limits problem in the original Tao-Mo form and also eliminates the unphysical behavior introduced by an earlier regularization while essentially preserving compliance with the second-order gradient expansion. The resulting simplified, regularized (sregTM) functional delivers performance on standard molecular and solid state test sets equal to that of the earlier revised, regularized Tao-Mo functional. Here, we address de-orbitalization of that new sregTM into a pure density functional. We summarize the failures of the Mejía-Rodríguez and Trickey de-orbitalization strategy [Phys. Rev. A 96, 052512 (2017)] when used with both versions. We discuss how those failures apparently arise in the so-called z' indicator function and in substitutes for the reduced density Laplacian in the parent functionals. Then, we show that the sregTM functional can be de-orbitalized somewhat well with a rather peculiarly parameterized version of the previously used deorbitalizer. We discuss, briefly, a de-orbitalization that works in the sense of reproducing error patterns but that apparently succeeds by cancelation of major qualitative errors associated with the de-orbitalized indicator functions α and z, hence, is not recommended. We suggest that the same issue underlies the earlier finding of comparatively mediocre performance of the de-orbitalized Tao-Perdew-Staroverov-Scuseri functional. Our work demonstrates that the intricacy of such two-indicator functionals magnifies the errors introduced by the Mejía-Rodríguez and Trickey de-orbitalization approach in ways that are extremely difficult to analyze and correct.

Advanced electrokinetic characterization of layer-by-layer assembled polyelectrolyte membranes: Consideration and use of the electrokinetic leakage phenomenon

The sensitivity of zeta potential to the sign of the surface charge of membranes makes it an interesting parameter for the characterization of layer-by-layer (Lbl) modified polyelectrolytes membranes. However, during tangential electrokinetic measurements, a non-negligible parasitic phenomenon referred to as “electrokinetic leakage” may occur. If not taken into account, this phenomenon can lead to dramatic quantitative and qualitative errors, especially when it comes to characterize the surface charge of layer-by-layer assembled polyelectrolyte membranes. In this work, we show that it can lead to substantial errors when interpreting experimental data, including misinterpreting the sign of the membrane surface charge density. An advanced protocol based on the measurement of the streaming current by varying the spacing between the two samples needed for the measurements allows to (i) correct the raw data for the electrokinetic leakage phenomenon and thus to correctly and accurately determine the zeta potential of the membrane surface and (ii) to detect whether polyelectrolytes are deposited only on the membrane surface or whether they can also penetrate into the membrane pores. The approach followed and the conclusions drawn in this study can be straightforwardly applied to any kind of membrane functionalization.

Synthetic white balancing for intra-operative hyperspectral imaging.

Hyperspectral imaging shows promise for surgical applications to non-invasively provide spatially resolved, spectral information. For calibration purposes, a white reference image of a highly reflective Lambertian surface should be obtained under the same imaging conditions. Standard white references are not sterilizable and so are unsuitable for surgical environments. We demonstrate the necessity for in situ white references and address this by proposing a novel, sterile, synthetic reference construction algorithm. The use of references obtained at different distances and lighting conditions to the subject were examined. Spectral and color reconstructions were compared with standard measurements qualitatively and quantitatively, using and normalized RMSE, respectively. The algorithm forms a composite image from a video of a standard sterile ruler, whose imperfect reflectivity is compensated for. The reference is modeled as the product of independent spatial and spectral components, and a scalar factor accounting for gain, exposure, and light intensity. Evaluation of synthetic references against ideal but non-sterile references is performed using the same metrics alongside pixel-by-pixel errors. Finally, intraoperative integration is assessed though cadaveric experiments. Improper white balancing leads to increases in all quantitative and qualitative errors. Synthetic references achieve median pixel-by-pixel errors lower than 6.5% and produce similar reconstructions and errors to an ideal reference. The algorithm integrated well into surgical workflow, achieving median pixel-by-pixel errors of 4.77% while maintaining good spectral and color reconstruction. We demonstrate the importance of in situ white referencing and present a novel synthetic referencing algorithm. This algorithm is suitable for surgery while maintaining the quality of classical data reconstruction.

Primary and subharmonic resonance features of a graphene nanoplatelet strengthened beam in a thermal ambient directly attacking nonlinear integro-partial differential governing equations

The nonlinear aspects of advanced structures may be utilized for design purposes and making use of advantages and avoiding disadvantages of such structures. On the other hand, developing information from secondary resonance examinations of advanced structures is worthwhile for engineering objectives such as mass detection, energy harvesting and damage detection of systems likewise structures. Moreover, a precise solution methodology discards any possibility of qualitative errors and incorrect prejudice. Accordingly, for the first time, the nonlinear primary resonance alongside the subharmonic resonance of an advanced beam structure strengthened by means of graphene nanoplatelets in a thermal ambient is addressed in details employing the direct method of multiple scales. With the aim of defeating to the disadvantageous influences of the discretization procedure on the nonlinear dynamics of the graphene nanoplatelet strengthened beam, the nonlinear integro-partial differential equation of motion in accompanied by the in-homogeneous boundary conditions are attacked directly resorting to the method of multiple scales. It is shown that how an FGX distribution pattern of graphene nanoplatelets for a beam subjected to a subharmonic resonance excitation relative to an FGO distribution pattern effectively extends the range of excitation frequency that leads to a bistable solution. This deduction is very proficient for harvesting energy scopes. A similar finding is observed for a CC beam with respect to a CS beam. It is seen that when an FGX beam is exposed to a subharmonic resonance in a wider range of force amplitude experiences a non-trivial equilibrium state relative to an FGO beam. However, the strengthening of the beam with graphene nanoplatelets decreases the lower bound of the excitation frequency required for the activation of subharmonic resonance more significant for an FGX distribution pattern. Moreover, the primary resonance frequency response shows different trend prior to and after the situation of the external force frequency to the first natural frequency ratio equal to one for an FGX and an FGO graphene nanoplatelet strengthened beams. The presented results open a new view of the future of engineering designs for various engineering scopes such as energy harvesting, mass detection and damage detection purposes employing advanced structures.

Characterization of inpaint residuals in interferometric measurements of the epoch of reionization

ABSTRACTTo mitigate the effects of Radio Frequency Interference (RFI) on the data analysis pipelines of 21 cm interferometric instruments, numerous inpaint techniques have been developed. In this paper, we examine the qualitative and quantitative errors introduced into the visibilities and power spectrum due to inpainting. We perform our analysis on simulated data as well as real data from the Hydrogen Epoch of Reionization Array (HERA) Phase 1 upper limits. We also introduce a convolutional neural network that is capable of inpainting RFI corrupted data. We train our network on simulated data and show that our network is capable of inpainting real data without requiring to be retrained. We find that techniques that incorporate high wavenumbers in delay space in their modelling are best suited for inpainting over narrowband RFI. We show that with our fiducial parameters discrete prolate spheroidal sequences (dpss) and clean provide the best performance for intermittent RFI while Gaussian progress regression (gpr) and least squares spectral analysis (lssa) provide the best performance for larger RFI gaps. However, we caution that these qualitative conclusions are sensitive to the chosen hyperparameters of each inpainting technique. We show that all inpainting techniques reliably reproduce foreground dominated modes in the power spectrum. Since the inpainting techniques should not be capable of reproducing noise realizations, we find that the largest errors occur in the noise dominated delay modes. We show that as the noise level of the data comes down, clean and dpss are most capable of reproducing the fine frequency structure in the visibilities.

Foundations of Thermoelectronics

The construction of the foundations of thermoelectronics became possible only after the correction of thermodynamic errors in the traditional theory of semiconductor electronics. It was these errors that determined the saturation of the operating parameters of semiconductor electronic devices, in particular, the saturation of the maximum clock frequency of processors. But in semiconductors, although these thermodynamic errors manifested themselves not only in the instrumental, but also in the technological aspect, they did not prohibit semiconductor electronics themselves. It&#39;s just that in the theory of semiconductor devices there were a number of qualitative errors that practitioners compensated for with “empirical corrections. So an electronics engineer often made devices not according to a strict theory (which simply did not exist until now), but on a hunch and according to empirical local laws. What was aggravated by the fact that ALL physics was "stuck" on the use of flat electron orbitals, which Pauling introduced for "two-dimensional" graphite and for which he received the Nobel Prize. But, Pauling himself, as an honest scientist, having discovered his mistake, tried to correct it by introducing “curved” orbitals for graphite itself. Now, after the restoration of the Planck-Einstein Quantization, it is shown how to get the correct orbitals instead of the mystical Schrödinger wave functions [1, 2, 3]. 1. Stanislav Ordin, «Gaps and Errors of the Schrödinger Equation»», Journal of Materials and Polymer Science (J mate poly sci), 2022; 2(3): p. 1-6. 2. Stanislav Vladimirovich Ordin, Book: “FOUNDATIONS OF Planck-Einstein Quantization (Thematic collection of recent studies reviewed in scientific journals)”, LAP LAMBERT Academic Publishing, 2021, ISBN 978-620-4-21066-7, 110 pp. 3. Stanislav Ordin, "Foundations of Quantization Principles". Jenny Stanford Publishing Pte Ltd, 2023, 235 рр.

Limits on using the clock drawing test as a measure to evaluate patients with neurological disorders

BackgroundThe Clock Drawing Test (CDT) is used as a quick-to-conduct test for the diagnosis of dementia and a screening tool for cognitive impairments in neurological disorders. However, the association between the pattern of CDT impairments and the location of brain lesions has been controversial. We examined whether there is an association between the CDT scores and the location of brain lesions using the two available scoring systems.MethodOne hundred five patients with brain lesions identified by CT scanning were recruited for this study. The Montreal Cognitive Assessment (MoCA) battery including the CDT were administered to all partcipants. To score the CDT, we used a qualitative scoring system devised by Rouleau et al. (1992). For the quantitative scoring system, we adapted the algorithm method used by Mendes-Santos et al. (2015) based on an earlier study by Sunderland et al. (1989). For analyses, a machine learning algorithm was used.ResultsRemarkably, 30% of the patients were not detected by the CDT. Quantitative and qualitative errors were categorized into different clusters. The classification algorithm did not differentiate the patients with traumatic brain injury ‘TBI’ from non-TBI, or the laterality of the lesion. In addition, the classification accuracy for identifying patients with specific lobe lesions was low, except for the parietal lobe with an accuracy of 63%.ConclusionThe CDT is not an accurate tool for detecting focal brain lesions. While the CDT still is beneficial for use with patients suspected of having a neurodegenerative disorder, it should be cautiously used with patients with focal neurological disorders.

Implicit Error, Uncertainty and Confidence in Visualization: An Archaeological Case Study.

While we know that the visualization of quantifiable uncertainty impacts the confidence in insights, little is known about whether the same is true for uncertainty that originates from aspects so inherent to the data that they can only be accounted for qualitatively. Being embedded within an archaeological project, we realized how assessing such qualitative uncertainty is crucial in gaining a holistic and accurate understanding of regional spatio-temporal patterns of human settlements over millennia. We therefore investigated the impact of visualizing qualitative implicit errors on the sense-making process via a probe that deliberately represented three distinct implicit errors, i.e., differing collection methods, subjectivity of data interpretations and assumptions on temporal continuity. By analyzing the interactions of 14 archaeologists with different levels of domain expertise, we discovered that novices became more actively aware of typically overlooked data issues and domain experts became more confident of the visualization itself. We observed how participants quoted social factors to alleviate some uncertainty, while in order to minimize it they requested additional contextual breadth or depth of the data. While our visualization did not alleviate all uncertainty, we recognized how it sparked reflective meta-insights regarding methodological directions of the data. We believe our findings inform future visualizations on how to handle the complexity of implicit errors for a range of user typologies and for highly data-critical application domains such as the digital humanities.

PL03 Presentation Time: 2:30 PM: A Deep Learning-Based Self-Adapting Ensemble Method for Segmentation in Gynecological Brachytherapy

<h3>1. Purpose</h3> Auto-segmentation is highly desired in brachytherapy treatment planning since patients' time between implantation and treatment is limited. Minimizing the HRCTV and OARs contouring variability can improve the plan quality consistency. In deep learning-based image segmentation area, lots of novel architectures are proposed in organ segmentation. However, fine-tuning of the hyper-parameters is tedious and time-consuming. This study aims to apply a self-configured ensemble method for fast and reproducible auto-segmentation in gynecological cancer. <h3>2. Methods and Materials</h3> <b>2.1 Patient Data:</b> 237 brachytherapy cases were selected in the retrospective study. 207 patients are used for training and 30 patients for tests. The patients were treated with applicator set among Utrecht Applicators, Ovoid Applicator, Vaginal Multi-Channel Applicator, Fletcher Applicator, and Tandem with up to 10 interstitial needles. The HRCTV and OARs were manually delineated by an experienced radiation oncologist. <b>2.2 Geometric Evaluation:</b> In quantitative evaluation, we used the Dice Similarity Coefficient (DSC), Average Surface Distance(ASD), and 95% Hausdorff distance (HD95%) index. In qualitative evaluation, two radiation oncologists evaluated the auto-segmentation results visually and graded the results using a 4-point Likert scale. <b>2.3 Dosimetric Evaluation:</b> For HRCTV, D_90%, V_100%, V_150%, V_200% were evaluated. For OARs, D_2cc, D_1cc, D_0.1cc, and D_max were evaluated. Since the dose distribution, and by extension, dose volume parameters, can vary largely among plans, a customized python program was developed to calculate the dose volume parameters based on predicted contours (P_predicted) using the dose map of original plan created based on manual contours (P_orginal). Namely, the P_predicted and P_orginal share the same dose map, simulating same applicator position, source dwell position and dwell time. Model performance was quantified by calculating the residual of dose volume parameters between P_predicted and P_orginal. <b>2.4 Auto-segmentation Network</b> In this study, nnU-Net was selected to provide a standardized workflow to achieve accurate and reproducible segmentation. The architecture template of nnU-net is a ‘U-Net-like' encode-decoder with skip connection and instance normalization. It provides three architectures based on the U-Net backbone: a 2D U-Net, a 3D U-Net which training all images at full image resolution (3D-Fullres), and a 3D U-Net cascade network (3D-Cascade). Networks are ensembled by averaging softmax probabilities. <b>2.5 Statistical Analysis</b> Cohen's kappa (κ) was calculated to evaluate the interobserver agreement between the two radiation oncologists at qualitative evaluation. <h3>3. Results</h3> <b>3.1</b> Geometric EvaluationIn quantitative evaluation, 3D-Cascade achieves the best performance in the bladder (DSC: 0.936±0.051, HD95%: 3.503±1.956, ASD: 0.944±0.503), rectum (DSC: 0.831±0.074, HD95%: 7.579±5.857, ASD: 3.6±3.485), HRCTV (DSC: 0.836±0.07, HD95%: 7.42±5.023, ASD: 2.094±1.311). The qualitative evaluation shows that in more than 90% of data sets, no or only minor visually detectable qualitative segmentation errors occurred. Good interobserver agreement was achieved on 2D (κ = 0.67), 3D-Fullres (κ=0.69), 3D-Cascade (κ=0.78) and ensemble (κ=0.71) segmentations. <b>3.2 Dosimetric Evaluation</b>The average difference for ΔD90% in HRCTV is less than 7.8%, and for OARs, the average difference in D2cc is smaller than 15%. <h3>4. Conclusion</h3> In this work, we have demonstrated that it is feasible to use a standardized nnU-net method for OARs and HRCTV segmentation in gynecological cancer.

Rey-Osterrieth Complex Figure Test in Differentiating Between Left and Right Lesions Caused by Brain Tumors and Stroke

The aim of this study was to examine whether the ROCF qualitative scoring system developed by Loring, Lee and Meador for differentiating complex partial seizures originating from either the right or left temporal lobe is effective in differentiating left-sided and right-sided brain lesions that are the result of cerebrovascular insult or brain tumours. We were also interested in determining whether this scoring system, which was developed for scoring trials with delayed recall, could be applied to trials with immediate recall and copying. The study consisted of 24 participants with lesions of the left hemisphere and 33 participants with right-sided lesions. Participants with right-sided lesions had a significantly greater number of qualitative errors in copying, immediate and delayed recall, and these three variables are the major contributors in distinguishing between groups. Based on these variables and quantitative results on copying, immediate and delayed recall, we were able to correctly classify 78.3 % of participants with left-sided lesions and 66.7 % of participants with right-sided lesions. Given that more than 90 % of participants with left-sided lesions had two or more errors in delayed recall, it is clear that the criterion of two or more errors which was set by Loring, Lee and Meador for patients with a right-sided focus in epilepsy is not applicable to patients with tumours and strokes. These results do not confirm the usefulness of qualitative errors for distinguishing left-sided and right-sided lesions caused by a tumour or stroke, except, perhaps, in cases of very high results (six or more errors) and when one of these errors is error X in immediate and/or delayed recall.

Comprehensive qualitative characterization of linguistic performance profiles in primary progressive aphasia: a multivariate study with FDG-PET

Primary progressive aphasia (PPA) classification relies on profile characterization of quantitatively impaired/spared performance in language tasks. In this study, we coextracted 8 qualitative types of errors in 67 PPA patients submitted to a comprehensive language assessment. Canonical correlation analysis was applied to simultaneously correlate qualitative errors and brain metabolism, collected with FDG-PET. Results showed the contribution of semantic, syntactic and working memory errors associated with specific correlates of regional metabolic changes. Reduced metabolism in the left fusiform gyrus, anterior-middle and inferior-temporal gyri and middle-temporal pole correlated with an increase of semantic errors. Hypometabolism in the left inferior, middle, and superior frontal gyri, insula and right middle-occipital gyrus was related to syntactic errors. Higher metabolism in the bilateral pallidum, putamen, and left thalamus, as well as hypometabolism in the left angular and supramarginal gyri, inferior-parietal lobule, posterior-middle and inferior-temporal gyri and posterior cingulum predicted the increase of working memory errors. A relevant role of working memory subcomponents was associated with distinct neural systems. Patients’ profiles are easily represented in a qualitative multidimensional space, in which mixed PPA overlapped with different phenotypes.

Comment on: “Effects of rotation on the Landau levels in an elastic medium with a spiral dislocation”

In this Comment we analyse a model proposed recently with the purpose of studying the effects of rotation on the interaction of a point charge with a uniform magnetic field in an elastic medium with a spiral dislocation. In particular we focus on the approximation proposed by the authors that consists of changing the left boundary condition in order to obtain analytical results. We show that this approximation leads to quantitative and qualitative errors, the most relevant one being a wrong prediction of the level spacing.

Association between gait speed and errors on the Clock Drawing Test in older adults with mild cognitive impairment

Individuals with mild cognitive impairment (MCI) often make qualitative errors on the Clock Drawing Test (CDT), and these errors are reported to be associated with lower scores on neuropsychological assessments. Gait speed is also closely associated with cognitive dysfunction. However, the association between CDT errors and gait speed has not been investigated in individuals with MCI. Therefore, in this study, we explored the association between gait speed and qualitative errors on the CDT. Participants were 196 outpatients at a memory clinic with a clinical dementia rating of 0.5. The CDT was evaluated using the method of Cahn et al. The participants were divided into tertiles of normal and maximum gait speeds. The CDT error types of stimulus-bound response, conceptual deficit (CD), and planning deficit were found in 24.5%, 29.6%, and 30.1% of the participants, respectively. CD was found in 43.6% of the slowest tertile of maximum gait and in 22.2% of the fastest tertile. Multiple linear regression analysis gait speeds as objective continuous variables revealed that CD was significantly negatively associated with maximum gait, but not with normal gait. No other error types were associated with gait speeds. Only CD type error on the CDT was negatively associated with maximum gait speed, but not normal gait speed in the current study. The association between the qualitative error on the CDT and gait speed provides further basis of the clinical importance of qualitative assessments of CDT.

An accurate, non-empirical method for incorporating decoherence into Ehrenfest dynamics.

In mixed quantum-classical nonadiabatic molecular dynamics methods, the anchoring of the electronic wave function to a single nuclear geometry results in both quantitative and qualitative errors in the dynamics. In the context of both Ehrenfest and trajectory surface hopping methods, methods for incorporating decoherence are widely used to eliminate these errors. However, the accuracy of these methods often depends strongly on the parameterization of the decoherence time and/or other related quantities. Here, we present a refinement of the recently introduced collapse to a block (TAB) scheme for incorporating decoherence into Ehrenfest dynamics. The proposed approach incorporates an approximation to the history of the population dynamics and treats the coherence decay as Gaussian, rather than exponential. This method uses parameters that can be obtained from first principles, rather than empirical fitting. Application to one-dimensional models indicates excellent agreement with numerically exact simulations. We also introduce a second refinement to the TAB method: a robust linear least-squares algorithm for determining collapse probabilities.

Diffusion Barriers for Carbon Monoxide on the Cu(001) Surface Using Many-Body Perturbation Theory and Various Density Functionals.

First-principles calculations play a key role in understanding the interactions of molecules with transition-metal surfaces and the energy profiles for catalytic reactions. However, many of the commonly used density functionals are not able to correctly predict the surface energy as well as the adsorption site preference for a key molecule such as CO, and it is not clear to what extent this shortcoming influences the prediction of reaction or diffusion pathways. Here, we report calculations of carbon monoxide diffusion on the Cu(001) surface along the [100] and [110] pathways, as well as the surface energy of Cu(001), and CO-adsorption energy and compare the performance of the Perdew-Burke-Ernzerhof (PBE), PBE + D2, PBE + D3, RPBE, Bayesian error estimation functional with van der Waals correlation (BEEF-vdW), HSE06 density functionals, and the random phase approximation (RPA), a post-Hartree-Fock method based on many-body perturbation theory. We critically evaluate the performance of these methods and find that RPA appears to be the only method giving correct site preference, overall barrier, adsorption enthalpy, and surface energy. For all of the other methods, at least one of these properties is not correctly captured. These results imply that many density functional theory (DFT)-based methods lead to qualitative and quantitative errors in describing CO interaction with transition-metal surfaces, which significantly impacts the description of diffusion pathways. It is well conceivable that similar effects exist when surface reactions of CO-related species are considered. We expect that the methodology presented here will be used to get more detailed insights into reaction pathways for CO conversion on transition-metal surfaces in general and Cu in particular, which will allow us to better understand the catalytic and electrocatalytic reactions involving CO-related species.