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Amyotrophic lateral sclerosis (ALS) is a severe motor neuron disease with uncertain genetic predisposition in most sporadic cases. The spatial architecture of cell types and gene expression are the basis of cell-cell interactions, biological function and disease pathology, but are not well investigated in the human motor cortex, a key ALS-relevant brain region. Recent studies indicated single nucleus transcriptomic features of motor neuron vulnerability in ALS motor cortex. However, the brain regional vulnerability of ALS-associated genes and the genetic link between region-specific genes and ALS risk remain largely unclear. Here, we developed an entropy-weighted differential gene expression matrix-based tool (SpatialE) to identify the spatial enrichment of gene sets in spatial transcriptomics. We benchmarked SpatialE against another enrichment tool (multimodal intersection analysis) using spatial transcriptomics data from both human and mouse brain tissues. To investigate regional vulnerability, we analysed three human motor cortex and two dorsolateral prefrontal cortex tissues for spatial enrichment of ALS-associated genes. We also used Cell2location to estimate the abundance of cell types in ALS-related cortex layers. To dissect the link of regionally expressed genes and ALS risk, we performed burden analyses of rare loss-of-function variants detected by whole-genome sequencing in ALS patients and controls, then analysed differential gene expression in the TargetALS RNA-sequencing dataset. SpatialE showed more accurate and specific spatial enrichment of regional cell type markers than multimodal intersection analysis in both mouse brain and human dorsolateral prefrontal cortex. Spatial transcriptomic analyses of human motor cortex showed heterogeneous cell types and spatial gene expression profiles. We found that 260 manually curated ALS-associated genes are significantly enriched in layer 5 of the motor cortex, with abundant expression of upper motor neurons and layer 5 excitatory neurons. Burden analyses of rare loss-of-function variants in Layer 5-associated genes nominated NOMO1 as a novel ALS-associated gene in a combined sample set of 6814 ALS patients and 3324 controls (P = 0.029). Gene expression analyses in CNS tissues revealed downregulation of NOMO1 in ALS, which is consistent with a loss-of-function disease mechanism. In conclusion, our integrated spatial transcriptomics and genomic analyses identified regional brain vulnerability in ALS and the association of a layer 5 gene (NOMO1) with ALS risk.
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Esclerose Lateral Amiotrófica , Córtex Motor , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Humanos , Camundongos , Animais , Córtex Motor/metabolismo , Córtex Motor/patologia , Transcriptoma , Genômica/métodos , Córtex Pré-Frontal/metabolismo , Córtex Pré-Frontal/patologia , Neurônios Motores/metabolismo , Neurônios Motores/patologia , MasculinoRESUMO
BACKGROUND: Physiological changes associated with ageing could negatively impact the crisis resource management skills of acute care physicians. This study was designed to determine whether physician age impacts crisis resource management skills, and crisis resource management skills learning and retention using full-body manikin simulation training in acute care physicians. METHODS: Acute care physicians at two Canadian universities participated in three 8-min simulated crisis (pulseless electrical activity) scenarios. An initial crisis scenario (pre-test) was followed by debriefing with a trained facilitator and a second crisis scenario (immediate post-test). Participants returned for a third crisis scenario 3-6 months later (retention post-test). RESULTS: For the 48 participants included in the final analysis, age negatively correlated with baseline Global Rating Scale (GRS; r=-0.30, P<0.05) and technical checklist scores (r=-0.44, P<0.01). However, only years in practice and prior simulation experience, but not age, were significant in a subsequent stepwise regression analysis. Learning from simulation-based education was shown with a mean difference in scores from pre-test to immediate post-test of 2.28 for GRS score (P<0.001) and 1.69 for technical checklist correct score (P<0.001); learning was retained for 3-6 months. Only prior simulation experience was significantly correlated with a decreased change in learning (r=-0.30, P<0.05). CONCLUSIONS: A reduced amount of prior simulation training and increased years in practice, but not age on its own, were significant predictors of low baseline crisis resource management performance. Simulation-based education leads to crisis resource management learning that is well retained for 3-6 months, regardless of age or years in practice.
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Internato e Residência , Médicos , Humanos , Estudos Prospectivos , Competência Clínica , CanadáRESUMO
PURPOSE: Simulation-based education in ultrasound-guided regional anesthesia (UGRA) improves knowledge, skills, and patient outcomes. Nevertheless, it is not known how simulation-based UGRA education is used across Canada. We aimed to characterize the current use of simulation-based UGRA education in Canadian anesthesiology residency training programs. METHODS: We developed and distributed a structured national survey to simulation leads of all 17 Canadian anesthesiology residency training programs. The survey inquired about program demographics, simulation modalities, facilitators and barriers to simulation use, use for assessment, and beliefs around simulation-based UGRA education. We gathered data from August to November 2023 and summarized our findings descriptively. RESULTS: Fifteen programs (88%) responded to our survey. Eight programs (53%) used UGRA simulation for technical training and nine programs (60%) for nontechnical training. The most common simulators used were live model scanning (13 programs, 87%) and gel phantom models (7 programs, 47%). Five programs (33%) mandated simulation-based UGRA in their curriculum. We found that deliberate practice and improved patient safety were most valued in simulation training while lack of funding and faculty availability were the most common barriers to implementation. Most respondents agreed that formative simulation-based education would improve trainee skills and called for greater standardization. Nevertheless, there were mixed responses regarding summative UGRA simulation and the need for simulation proficiency before clinical practice. CONCLUSIONS: Our findings show significant variations in simulation implementation and views on UGRA simulation-based education among Canadian anesthesiology residency training programs. Future studies should explore avenues to overcome barriers and improve knowledge translation in UGRA.
RéSUMé: OBJECTIF: La formation basée sur la simulation en anesthésie régionale échoguidée améliore les connaissances, les compétences et les issues pour les patient·es. Néanmoins, on ne sait pas comment la formation en AR échoguidée basée sur la simulation est utilisée au Canada. Nous avons cherché à caractériser l'utilisation actuelle de l'enseignement de l'AR échoguidée basée sur la simulation dans les programmes canadiens de résidence en anesthésiologie. MéTHODE: Nous avons élaboré et distribué un sondage national structuré aux responsables de la simulation des 17 programmes canadiens de résidence en anesthésiologie. L'enquête portait sur les données démographiques du programme, les modalités de simulation, les facilitateurs et les obstacles à l'utilisation de la simulation, son utilisation pour l'évaluation, et les croyances concernant l'éducation en AR échoguidée basée sur la simulation. Nous avons recueilli des données d'août à novembre 2023 et résumé nos résultats de manière descriptive. RéSULTATS: Quinze programmes (88 %) ont répondu à notre sondage. Huit programmes (53 %) utilisent la simulation en AR échoguidée pour la formation technique et neuf programmes (60 %) pour la formation non technique. Les simulateurs les plus couramment utilisés étaient le balayage sur modèles vivants (13 programmes, 87 %) et les modèles de fantômes en gel (7 programmes, 47 %). Cinq programmes (33 %) ont rendu obligatoire l'AR échoguidée basée sur la simulation dans leur programme. Nous avons constaté que la pratique délibérée et l'amélioration de la sécurité des patient·es étaient les plus appréciées dans la formation par simulation, tandis que le manque de financement et la disponibilité du corps professoral étaient les obstacles les plus courants à la mise en Åuvre. La plupart des répondant·es ont convenu que l'éducation formative basée sur la simulation améliorerait les compétences des stagiaires et ont appelé à une plus grande standardisation. Néanmoins, les réponses étaient mitigées concernant la simulation sommative en AR échoguidée et la nécessité d'une maîtrise de la simulation avant la pratique clinique. CONCLUSION: Nos résultats montrent des variations significatives dans la mise en Åuvre de la simulation et les points de vue sur l'éducation basée sur la simulation en AR échoguidée parmi les programmes canadiens de résidence en anesthésiologie. Les études futures devraient explorer les moyens de surmonter les obstacles et d'améliorer l'application des connaissances à l'anesthésie régionale échoguidée.
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PURPOSE: Simulation-based medical education (SBME) is provided by all anesthesiology residency programs in Canada. The purpose of this study was to characterize SBME in Canadian anesthesiology residency training programs. METHODS: We administered a 21-question survey to the simulation director/coordinator for all 17 Canadian academic departments of anesthesiology from October 2019 to January 2020. The survey consisted of questions pertaining to the characteristics of the simulation centres, their faculty, learners, curriculum, and assessment processes. RESULTS: All 17 residency training programs participated in the survey and reported large variability in the number and formal training of simulation faculty and in content delivery. Five programs (29%) did not provide faculty recognition for curriculum design and running simulation sessions. Most programs offered one to four simulation sessions per academic year for each year of residency. All programs offered mannequin-based and part-task trainers for teaching technical and nontechnical skills. Fourteen programs (82%) offered interprofessional and interdisciplinary simulation sessions, and ten programs (59%) did not include in situ simulation training. Commonly reported barriers to faculty involvement were lack of protected time (12 programs, 71%), lack of financial compensation (ten programs, 59%), and lack of appreciation for SBME (seven programs, 41%). CONCLUSION: Large variability exists in the delivery of SBME in Canadian anesthesiology residency simulation programs, in part because of differences in financial/human resources and educational content. Future studies should explore whether training and patient outcomes differ between SBME programs and, if so, whether additional standardization is warranted.
RéSUMé: OBJECTIF: La formation médicale par simulation est offerte par tous les programmes de résidence en anesthésiologie au Canada. L'objectif de cette étude était de déterminer l'état actuel de la formation médicale par simulation dans les programmes canadiens de résidence en anesthésiologie. MéTHODE: D'octobre 2019 à janvier 2020, nous avons administré un sondage comportant 21 questions aux directions et équipes de coordination de la simulation des 17 départements universitaires d'anesthésiologie canadiens. L'enquête comportait des questions portant sur les caractéristiques des centres de simulation, le corps professoral, les apprenants et apprenantes, le programme d'études et les processus d'évaluation. RéSULTATS: Les 17 programmes de résidence ont tous participé à l'enquête et ont fait état d'une grande variabilité dans le nombre et la formation officielle du corps professoral en simulation ainsi que dans la prestation de contenu. Cinq programmes (29 %) n'ont pas reconnu le corps professoral en charge de la conception des programmes d'études et de l'organisation des séances de simulation. La plupart des programmes offraient une à quatre séances de simulation par année universitaire à chaque année de résidence. Tous les programmes disposaient de simulateurs d'entraînement pour tâches partielles et de mannequins pour enseigner des compétences techniques et non techniques. Quatorze programmes (82 %) offraient des séances de simulation interprofessionnelles et interdisciplinaires, et dix programmes (59 %) ne comportaient pas de formation par simulation in situ. Les obstacles les plus fréquemment signalés à la participation du corps professoral étaient le manque de temps protégé (12 programmes, 71 %), le manque de compensation financière (dix programmes, 59 %) et le manque d'appréciation de la formation médicale par simulation (sept programmes, 41 %). CONCLUSION: Il existe une grande variabilité dans la prestation de formation médicale par simulation dans les programmes de simulation pendant la résidence en anesthésiologie au Canada, causée en partie par des différences dans les ressources financières et humaines et par le contenu de la formation. Des études futures devraient déterminer si la formation et les issues pour les patient·es diffèrent d'un programme de formation médicale par simulation à l'autre et, dans l'affirmative, si une normalisation supplémentaire est justifiée.
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In this paper, a smart enzyme reactor (SER) was synthesized using immobilized tyrosinase (Tyr) in a photo-responsive hydrogel via a polydopamine-assisted self-assembly strategy for purifying water from phenol contaminated water. PDA was not only utilized as a binder between Tyr and the hydrogel to prevent the leakage of Tyr with relatively high enzymatic activity from the SER, but also acted as a light absorber to trigger the hydrophilic/hydrophobic switching of PNIPAm hydrogels to realize the efficient reclamation of clean water. Experimental results showed that the SER maintained a well-defined porous structure with excellent elasticity, which was beneficial for water transport and enzyme accessibility. And the stability and reusability of Tyr in the degradation of phenol were all improved. Furthermore, clean water could be reclaimed completely and facilely by light irradiation after enzymatic remediation in the SER.
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Hidrogéis , Fenol , Elasticidade , Porosidade , ÁguaRESUMO
PURPOSE: Patients with coronavirus disease (COVID-19) are at risk of requiring mechanical ventilation, and concerns of protecting healthcare workers during aerosol-generating medical procedures has led to the design of the aerosol box. METHODS: We conducted a randomized crossover mannequin-based simulation study to compare airway management with and without the aerosol box. Thirty-five anesthesiology participants and three critical care participants with more than 50 intubations with videolaryngoscopes were recruited. There were four airway simulations with and without the aerosol box (normal, pharyngeal swelling, cervical spine rigidity, and tongue edema). Each participant intubated the mannequin in eight consecutive simulations. The primary outcome of the study was time to intubation. Secondary outcomes included intubation attempts, optimization maneuvers, and personal protective equipment breaches. RESULTS: Mean (standard deviation [SD]) time to intubation overall with the box was 30.9 (23.0) sec, while the time to intubation without the box was 25.1 (12.2) sec (mean difference, 5.8; 95% confidence interval [CI], -2.9 to 14.5). For the normal airway scenario, the mean (SD) time to intubation was 18.6 (3.5) sec for no box and 20.4 (3.3) sec for box (mean difference, 1.8; 95% CI, 0.2 to 3.4). During difficult airway scenarios only, the time to intubation was 34.4 (25.6) sec with the aerosol box and 27.3 (13.2) sec without the aerosol box (mean difference, 7.1; 95% CI, -2.5 to 16.7). There were more intubation attempts, personal protective equipment breaches, and optimization maneuvers during use of the aerosol box. CONCLUSIONS: In this mannequin-based simulation study, the use of the aerosol box increased the time to intubation in some contexts but not others. Further studies in a clinical setting should be conducted to make appropriate modifications to the aerosol box to fully elicit its efficacy and safety prior to implementation in airway guidelines for managing patients with COVID-19.
RéSUMé: OBJECTIF: Les patients atteints de la maladie à coronavirus (COVID-19) courent le risque d'avoir besoin de ventilation mécanique, et les inquiétudes quant à la protection des travailleurs de la santé pendant les interventions médicales générant des aérosols ont motivé la conception d'une boîte pour contenir les aérosols. MéTHODE: Nous avons réalisé une étude de simulation croisée randomisée sur des mannequins afin de comparer la prise en charge des voies aériennes avec et sans boîte pour contenir les aérosols. Trente-cinq anesthésiologistes et trois intensivistes ayant pratiqué plus de 50 intubations avec des vidéolaryngoscopes ont été recrutés. Quatre simulations de voies aériennes avec et sans boîte pour contenir les aérosols ont été évaluées (voies aériennes normales, Ådème pharyngé, rigidité de la colonne cervicale et Ådème de la langue). Chaque participant a intubé le mannequin dans huit simulations consécutives. Le critère d'évaluation principal de l'étude était le temps nécessaire à l'intubation. Les critères secondaires comprenaient le nombre de tentatives d'intubation, les manÅuvres d'optimisation et les bris de stérilité des équipements de protection individuelle. RéSULTATS: Globalement, le temps moyen (écart type [ÉT]) d'intubation avec la boîte était de 30,9 (23,0) sec, alors que le temps d'intubation sans la boîte était de 25,1 (12,2) sec (différence moyenne, 5,8; intervalle de confiance [IC] 95 %, -2,9 à 14,5). Dans la mise en situation simulant des voies aériennes normales, le temps moyen (ÉT) d'intubation était de 18,6 (3,5) sec sans la boîte et 20,4 (3,3) sec avec la boîte (différence moyenne, 1,8; IC 95 %, 0,2 à 3,4). Dans la mise en situation simulant des voies aériennes difficiles seulement, le temps d'intubation était de 34,4 (25,6) sec avec la boîte à aérosol et 27,3 (13,2) sec sans la boîte (différence moyenne, 7,1; IC 95 %, -2,5 à 16,7). Lors de l'utilisation de la boîte pour contenir les aérosols, les tentatives d'intubation étaient plus nombreuses, tout comme les bris de stérilité des équipements de protection individuelle et le nombre de manÅuvres d'optimisation. CONCLUSION: Dans cette étude de simulation sur mannequin, l'utilisation de la boîte pour contenir les aérosols a augmenté le temps nécessaire à l'intubation dans certains contextes mais pas dans d'autres. Des études supplémentaires devraient être réalisées dans un cadre clinique pour apporter des modifications adaptées à la boîte pour contenir les aérosols afin d'optimiser son efficacité et la sécurité qu'elle procure avant de l'ajouter aux recommandations de prise en charge des voies aériennes de patients atteints de la COVID-19.
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COVID-19 , Coronavirus , Aerossóis , Humanos , Intubação Intratraqueal , Manequins , SARS-CoV-2RESUMO
INTRODUCTION: As simulator fidelity (i.e., realism) increases from low to high, the simulator more closely resembles the real environment, but it also becomes more expensive. It is generally assumed that the use of high-fidelity simulators results in better learning; however, the effect of fidelity on learning non-technical skills (NTS) is unknown. This was a non-inferiority trial comparing the efficacy of high- vs low-fidelity simulators on learning NTS. METHODS: Thirty-six postgraduate medical trainees were recruited for the trial. During the pre-test phase, the trainees were randomly assigned to manage a scenario using either a high-fidelity simulator (HFS) or a low-fidelity simulator (LFS), followed by expert debriefing. All trainees then underwent a video recorded post-test scenario on a HFS, and the NTS were assessed between the two groups. The primary outcome was the overall post-test Ottawa Global Rating Scale (OGRS), while controlling for overall pre-test OGRS scores. Non-inferiority between the LFS and HFS was based on a non-inferiority margin of greater than 1. RESULTS: For our primary outcome, the mean (SD) post-test overall OGRS score was not significantly different between the HFS and LFS groups after controlling for pre-test overall OGRS scores [3.8 (0.9) vs 4.0 (0.9), respectively; mean difference, 0.2; 95% confidence interval, -0.4 to 0.8; P = 0.48]. For our secondary outcomes, the post-test total OGRS score was not significantly different between the HFS and LFS groups after controlling for pre-test total OGRS scores (P = 0.33). There were significant improvements in mean overall (P = 0.01) and total (P = 0.003) OGRS scores from pre-test to post-test. There were no significant associations between postgraduate year (P = 0.82) and specialty (P = 0.67) on overall OGRS performance. CONCLUSION: This study suggests that low-fidelity simulators are non-inferior to the more costly high-fidelity simulators for teaching NTS to postgraduate medical trainees.
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Competência Clínica , Treinamento com Simulação de Alta Fidelidade , Internato e Residência/métodos , Treinamento por Simulação/métodos , Avaliação Educacional , Feminino , Humanos , MasculinoRESUMO
INTRODUCTION: Simulation training has evolved as an important component of postgraduate surgical education and has shown to be effective in teaching procedural skills. Despite potential benefits to low- and middle-income countries (LMIC), simulation training is predominately used in high-income settings. This study evaluates the effectiveness of simulation training in one LMIC (Rwanda). METHODS: Twenty-six postgraduate surgical trainees at the University of Rwanda (Kigali, Rwanda) and Dalhousie University (Halifax, Canada) participated in the study. Participants attended one 3-hour simulation session using a high-fidelity, tissue-based model simulating the creation of an end ileostomy. Each participant was anonymously recorded completing the assigned task at three time points: prior to, immediately following, and 90 days following the simulation training. A single blinded expert reviewer assessed the performance using the Objective Structured Assessment of Technical Skill (OSATS) instrument. RESULTS: The mean OSATS score improvement for participants who completed all the assessments was 6.1 points [95 % Confidence Interval (CI) 2.2-9.9, p = 0.005]. Improvement was sustained over a 90-day period with a mean improvement of 4.1 points between the first and third attempts (95 % CI 0.3-7.9, p = 0.038). Simulation training was effective in both study sites, though most gains occurred with junior-level learners, with a mean improvement of 8.3 points (95 % CI 5.1-11.6, p < 0.001). Significant improvements were not identified for senior-level learners. CONCLUSION: This study supports the benefit for simulation in surgical training in LMICs. Skill improvements were limited to junior-level trainees. This work provides justification for investment in simulation-based curricula in Rwanda and potentially other LMICs.
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Currículo/normas , Países em Desenvolvimento , Educação de Pós-Graduação em Medicina/normas , Cirurgia Geral/educação , Ileostomia/educação , Internato e Residência/normas , Treinamento por Simulação/normas , Canadá , Competência Clínica , Países Desenvolvidos , Avaliação Educacional , Humanos , Internato e Residência/métodos , Pobreza , Ruanda , Fatores SocioeconômicosRESUMO
INTRODUCTION: During video laryngoscopy (VL) with angulated or hyper-curved blades, it is sometimes difficult to complete tracheal intubation despite a full view of the larynx. When using indirect VL, it has been suggested that it may be preferable to obtain a deliberately restricted view of the larynx to facilitate passage of the endotracheal tube. We used the GlideScope® GVL video laryngoscope (GVL) to test whether deliberately obtaining a restricted view would result in faster and easier tracheal intubation than with a full view of the larynx. METHODS: We recruited 163 elective surgical patients and randomly allocated the participants to one of two groups: Group F, where a full view of the larynx was obtained and held during GVL-facilitated tracheal intubation, and Group R, with a restricted view of the larynx (< 50% of glottic opening visible). Study investigators experienced in indirect VL performed the intubations. The intubations were recorded and the video recordings were subsequently assessed for total time to intubation, ease of intubation using a visual analogue scale (VAS; where 0 = easy and 100 = difficult), first-attempt success rate, and oxygen saturation after intubation. Complications were also assessed. RESULTS: The median [interquartile range (IQR)] time to intubation was faster in Group R than in Group F (27 [22-36] sec vs 36 [27-48] sec, respectively; median difference, 9 sec; 95% confidence interval [CI], 5 to 13; P < 0.001). The median [IQR] VAS rating for ease of intubation was also better in Group R than in Group F (14 [6-42) mm vs 50 mm [17-65], respectively; median difference, 20 mm; 95% CI, 10 to 31; P < 0.001). There was no difference between groups regarding the first-attempt success rate, oxygen saturation immediately after intubation, or complications. CONCLUSIONS: Using the GVL with a deliberately restricted view of the larynx resulted in faster and easier tracheal intubation than with a full view and with no additional complications. Our study suggests that obtaining a full or Cormack-Lehane grade 1 view may not be desirable when using the GVL. This trial was registered at ClinicalTrials.gov: NCT02144207.
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Glote , Intubação Intratraqueal/instrumentação , Intubação Intratraqueal/métodos , Laringoscópios , Laringoscopia/instrumentação , Laringe , Adulto , Idoso , Desenho de Equipamento , Feminino , Humanos , Laringoscopia/métodos , Masculino , Pessoa de Meia-Idade , Tempo , Gravação em VídeoRESUMO
Cognitive diagnostic models (CDMs) are a popular family of discrete latent variable models that model students' mastery or deficiency of multiple fine-grained skills. CDMs have been most widely used to model categorical item response data such as binary or polytomous responses. With advances in technology and the emergence of varying test formats in modern educational assessments, new response types, including continuous responses such as response times, and count-valued responses from tests with repetitive tasks or eye-tracking sensors, have also become available. Variants of CDMs have been proposed recently for modeling such responses. However, whether these extended CDMs are identifiable and estimable is entirely unknown. We propose a very general cognitive diagnostic modeling framework for arbitrary types of multivariate responses with minimal assumptions, and establish identifiability in this general setting. Surprisingly, we prove that our general-response CDMs are identifiable under Q -matrix-based conditions similar to those for traditional categorical-response CDMs. Our conclusions set up a new paradigm of identifiable general-response CDMs. We propose an EM algorithm to efficiently estimate a broad class of exponential family-based general-response CDMs. We conduct simulation studies under various response types. The simulation results not only corroborate our identifiability theory, but also demonstrate the superior empirical performance of our estimation algorithms. We illustrate our methodology by applying it to a TIMSS 2019 response time dataset.
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Grade of membership (GoM) models are popular individual-level mixture models for multivariate categorical data. GoM allows each subject to have mixed memberships in multiple extreme latent profiles. Therefore, GoM models have a richer modeling capacity than latent class models that restrict each subject to belong to a single profile. The flexibility of GoM comes at the cost of more challenging identifiability and estimation problems. In this work, we propose a singular value decomposition (SVD)-based spectral approach to GoM analysis with multivariate binary responses. Our approach hinges on the observation that the expectation of the data matrix has a low-rank decomposition under a GoM model. For identifiability, we develop sufficient and almost necessary conditions for a notion of expectation identifiability. For estimation, we extract only a few leading singular vectors of the observed data matrix and exploit the simplex geometry of these vectors to estimate the mixed membership scores and other parameters. We also establish the consistency of our estimator in the double-asymptotic regime where both the number of subjects and the number of items grow to infinity. Our spectral method has a huge computational advantage over Bayesian or likelihood-based methods and is scalable to large-scale and high-dimensional data. Extensive simulation studies demonstrate the superior efficiency and accuracy of our method. We also illustrate our method by applying it to a personality test dataset.
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Modelos Estatísticos , Psicometria , Humanos , Psicometria/métodos , Teorema de Bayes , Algoritmos , Simulação por ComputadorRESUMO
Acid value (AV) serves as an important indicator to assess the quality of oil, which can be used to judge the deterioration of edible oil. In order to realize the quantitative prediction of the AV of camellia seed oil, which was made from camellia oleifolia, hyperspectral data of 168 camellia seed oil samples were collected using a hyperspectral imaging system, which were related to their AV content measured via classical chemical titration. On the basis of hyperspectral full wavelengths, characteristic wavelengths, and fusing spectral and image features, the quantitative prediction AV models for camellia seed oil were established. The results demonstrating the 2Der-SPA-GLCM-PLSR model fusing spectral and image features stood out as the optimal choices for the AV prediction of camellia seed oil, with the correlation coefficient of calibration set (Rc2) and the correlation coefficient of prediction set (Rp2) at 0.9698 and 0.9581, respectively. Compared with those of 2Der-SPA-PLSR, the Rc2 and Rp2 were improved by 2.11% and 2.57%, respectively. Compared with those of 2Der-PLSR, the Rc2 and Rp2 were improved by 5.02% and 5.31%, respectively. Compared with the model based on original spectrum, the Rc2 and Rp2 were improved by 32.63% and 40.11%, respectively. After spectral preprocessing, characteristic wavelength selection, and fusing spectral and image features, the correlation coefficient of the optimal AV prediction model was continuously improved, while the root mean square error was continuously decreased. The research demonstrated that hyperspectral imaging technology could precisely and quantitatively predict the AV of camellia seed oil and also provide a new environmental method for detecting the AV of other edible oils, which is conducive to sustainable development.
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To achieve the rapid grade classification of camellia seed oil, hyperspectral imaging technology was used to acquire hyperspectral images of three distinct grades of camellia seed oil. The spectral and image information collected by the hyperspectral imaging technology was preprocessed by different methods. The characteristic wavelength selection in this study included the continuous projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS), and the gray-level co-occurrence matrix (GLCM) algorithm was used to extract the texture features of camellia seed oil at the characteristic wavelength. Combined with genetic algorithm (GA) and support vector machine algorithm (SVM), different grade classification models for camellia seed oil were developed using full wavelengths (GA-SVM), characteristic wavelengths (CARS-GA-SVM), and fusing spectral and image features (CARS-GLCM-GA-SVM). The results show that the CARS-GLCM-GA-SVM model, which combined spectral and image information, had the best classification effect, and the accuracy of the calibration set and prediction set of the CARS-GLCM-GA-SVM model were 98.30% and 96.61%, respectively. Compared with the CARS-GA-SVM model, the accuracy of the calibration set and prediction set were improved by 10.75% and 12.04%, respectively. Compared with the GA-SVM model, the accuracy of the calibration set and prediction set were improved by 18.28% and 18.15%, respectively. The research showed that hyperspectral imaging technology can rapidly classify camellia seed oil grades.
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Cognitive diagnostic models (CDMs) are discrete latent variable models popular in educational and psychological measurement. In this work, motivated by the advantages of deep generative modeling and by identifiability considerations, we propose a new family of DeepCDMs, to hunt for deep discrete diagnostic information. The new class of models enjoys nice properties of identifiability, parsimony, and interpretability. Mathematically, DeepCDMs are entirely identifiable, including even fully exploratory settings and allowing to uniquely identify the parameters and discrete loading structures (the "[Formula: see text]-matrices") at all different depths in the generative model. Statistically, DeepCDMs are parsimonious, because they can use a relatively small number of parameters to expressively model data thanks to the depth. Practically, DeepCDMs are interpretable, because the shrinking-ladder-shaped deep architecture can capture cognitive concepts and provide multi-granularity skill diagnoses from coarse to fine grained and from high level to detailed. For identifiability, we establish transparent identifiability conditions for various DeepCDMs. Our conditions impose intuitive constraints on the structures of the multiple [Formula: see text]-matrices and inspire a generative graph with increasingly smaller latent layers when going deeper. For estimation and computation, we focus on the confirmatory setting with known [Formula: see text]-matrices and develop Bayesian formulations and efficient Gibbs sampling algorithms. Simulation studies and an application to the TIMSS 2019 math assessment data demonstrate the usefulness of the proposed methodology.
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Cognitive diagnostic models are a powerful family of fine-grained discrete latent variable models in psychometrics. Within this family, the DINA model is a fundamental and parsimonious one that has received significant attention. Similar to other complex latent variable models, identifiability is an important issue for CDMs, including the DINA model. Gu and Xu (Psychometrika 84(2):468-483, 2019) established the necessary and sufficient conditions for strict identifiability of the DINA model. Despite being the strongest possible notion of identifiability, strict identifiability may impose overly stringent requirements on designing the cognitive diagnostic tests. This work studies a slightly weaker yet very useful notion, generic identifiability, which means parameters are identifiable almost everywhere in the parameter space, excluding only a negligible subset of measure zero. We propose transparent generic identifiability conditions for the DINA model, relaxing existing conditions in nontrivial ways. Under generic identifiability, we also explicitly characterize the forms of the measure-zero sets where identifiability breaks down. In addition, we reveal an interesting blessing-of-latent-dependence phenomenon under DINA-that is, dependence between the latent attributes can restore identifiability under some otherwise unidentifiable [Formula: see text]-matrix designs. The blessing of latent dependence provides useful practical implications and reassurance for real-world designs of cognitive diagnostic assessments.
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Modelos Teóricos , PsicometriaRESUMO
Structured Latent Attribute Models (SLAMs) are a family of discrete latent variable models widely used in education, psychology, and epidemiology to model multivariate categorical data. A SLAM assumes that multiple discrete latent attributes explain the dependence of observed variables in a highly structured fashion. Usually, the maximum marginal likelihood estimation approach is adopted for SLAMs, treating the latent attributes as random effects. The increasing scope of modern assessment data involves large numbers of observed variables and high-dimensional latent attributes. This poses challenges to classical estimation methods and requires new methodology and understanding of latent variable modeling. Motivated by this, we consider the joint maximum likelihood estimation (MLE) approach to SLAMs, treating latent attributes as fixed unknown parameters. We investigate estimability, consistency, and computation in the regime where sample size, number of variables, and number of latent attributes all can diverge. We establish the statistical consistency of the joint MLE and propose efficient algorithms that scale well to large-scale data for several popular SLAMs. Simulation studies demonstrate the superior empirical performance of the proposed methods. An application to real data from an international educational assessment gives interpretable findings of cognitive diagnosis.
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Latent class models are powerful statistical modeling tools widely used in psychological, behavioral, and social sciences. In the modern era of data science, researchers often have access to response data collected from large-scale surveys or assessments, featuring many items (large J) and many subjects (large N). This is in contrary to the traditional regime with fixed J and large N. To analyze such large-scale data, it is important to develop methods that are both computationally efficient and theoretically valid. In terms of computation, the conventional EM algorithm for latent class models tends to have a slow algorithmic convergence rate for large-scale data and may converge to some local optima instead of the maximum likelihood estimator (MLE). Motivated by this, we introduce the tensor decomposition perspective into latent class analysis with binary responses. Methodologically, we propose to use a moment-based tensor power method in the first step and then use the obtained estimates as initialization for the EM algorithm in the second step. Theoretically, we establish the clustering consistency of the MLE in assigning subjects into latent classes when N and J both go to infinity. Simulation studies suggest that the proposed tensor-EM pipeline enjoys both good accuracy and computational efficiency for large-scale data with binary responses. We also apply the proposed method to an educational assessment dataset as an illustration.
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Algoritmos , Modelos Estatísticos , Humanos , Análise de Classes Latentes , Funções Verossimilhança , Psicometria , Simulação por ComputadorRESUMO
Aeration is of great importance in landfill remediation. However, most existing studies on aerobic waste degradation ignore the presence of landfill gases. In this study, gas characteristics during aerobic waste degradation in the presence of landfill gas in lab-scale lysimeters were investigated. Oxygen (O2) was intermittently injected into municipal solid waste. Changes in the gas concentration and reaction rate of methane (CH4), carbon dioxide (CO2), and O2 during the reaction process were monitored and calculated. The results showed that all reactions, including aerobic degradation, CH4 oxidation, and anaerobic waste degradation, occurred simultaneously during landfill aeration. The maximum O2 consumption rate was 0.013 mol day-1 kg-1 dry waste. CH4 production was stimulated after the O2 content was insufficient to sustain the aerobic environment. Higher CH4 production was likely attributed to the remaining substrate and biomass from dead aerobic microorganisms decomposed by growing anaerobic microorganisms. Based on the biochemical reaction and principle of mass conservation, a gas balance model during waste aeration was established to analyze the proportions of aerobic waste degradation, CH4 oxidation, and anaerobic waste degradation. The CH4 oxidation reaction was more advantageous than the aerobic waste degradation reaction during aeration. With an increase in gas injection times, the anaerobic reaction gradually weakened. The maximum proportion of CH4 oxidation reaction could achieve at 21.4 % during aeration, which is of great significance for the waste degradation reaction. The maximum proportion of aerobic waste degradation and the minimum proportion of anaerobic waste degradation were approximately 16.0 % and 74.2 %, respectively. The results show that landfill gas should be considered in the progress of landfill aeration. This study provides a novel approach for calculating the proportion of reactions during landfill aeration, which deepens the understanding of the reaction process and contributes to the design of aerobic landfill projects.
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A prominent line of cultural evolutionary theory hypothesizes that religiously inspired prosocial behavior enhances the fecundity of pious groups, causing them to outcompete non-religious communities and spread their prosocial values. We present evidence concerning contemporary workplace safety, in the United States, that unexpectedly tested implications of this cultural evolutionary hypothesis. Avoiding workplace injury requires cooperation and injury influences fitness, thus cultural evolutionary theory would anticipate that religious communities should exhibit fewer workplace injuries. Indeed, we find that the proportion of a community adhering to a religion correlates negatively with rates of workplace injury in its private-sector establishments. This correlation emerges primarily when secular workplace safety authorities are not prominent, thus echoing evidence that religiously inspired prosocial behavior mainly occurs absent "earthly" sanctioning authorities. Furthermore, the percent of religiously affiliated individuals in a community correlates with safety investments, suggesting that workplace injury reductions in religious communities result from individually costly, group-benefitting cooperation.