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Bharadwaj et al. [1] present a comments paper evaluating the classification accuracy of several state-of-the-art methods using EEG data averaged over random class samples. According to the results, some of the methods achieve above-chance accuracy, while the method proposed in [2], that is the target of their analysis, does not. In this rebuttal, we address these claims and explain why they are not grounded in the cognitive neuroscience literature, and why the evaluation procedure is ineffective and unfair.
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This perspective summarizes our group's extensive research in the realm of organometallic lanthanide complexes, while also placing the catalytic reactions supported by these species within the context of known lanthanide catalysis worldwide, with a specific focus on phosphorus-based catalytic reactions such as intermolecular hydrophosphination and hydrophosphinylation. α-Metalated N,N-dimethylbenzylamine ligands have been utilized to generate homoleptic lanthanide complexes, which have subsequently proven to be highly active lanthanum-based catalysts. The main goal of our research program has been to enhance the catalytic efficiency of lanthanum-based complexes, which began with initial successes in the stoichiometric synthesis of organometallic lanthanide complexes and utilization of these species in catalytic hydrophosphination reactions. Not only have these species supported traditional lanthanide catalysis, such as the hydrophosphination of heterocumulenes like carbodiimides, isocyanates, and isothiocyanates, but they have also been effective for a plethora of catalytic reactions tested thus far, including the hydrophosphinylation and hydrophosphorylation of nitriles, hydrophosphination and hydrophosphinylation of alkynes and alkenes, and the heterodehydrocoupling of silanes and amines. Each of these catalytic transformations is meritorious in its own right, offering new synthetic routes to generate organic scaffolds with enhanced functionality while concurrently minimizing both waste generation and energy consumption. Objectives: We aim for the research summary presented herein to inspire and encourage other researchers to investigate f-element based stoichiometric and catalytic reactions. Our efforts in this field began with the recognition that potassium salts of benzyldimethylamine preferred deprotonation at the α-position, rather than the ortho-position, and we wondered if this regiochemistry would be retained in the formation of lanthanide complexes. The pursuit of this simple idea led first to a series of structurally fascinating homoleptic organometallic lanthanide complexes with surprisingly good stability. Fundamental studies of the protonolysis chemistry of these complexes ultimately revealed highly versatile lanthanide-based precatalysts that have propelled a catalytic investigation spanning more than a decade. We anticipate that this summative perspective will animate the synthetic as well as biological communities to consider La(DMBA)3-based catalytic methods in the synthesis of functionalized organic scaffolds as an atom-economic, convenient, and efficient methodology. Ultimately, we envision our work making a positive impact on the advancement of novel chemical transformations and contributing to progress in various fields of science and technology.
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Categorical search has been heavily investigated over the past decade, mostly using natural categories that leave the underlying category mental representation unknown. The categorization literature offers several theoretical accounts of category mental representations. One prominent account is that separate learning systems account for classification: an explicit learning system that relies on easily verbalized rules and an implicit learning system that relies on an associatively learned (nonverbalizable) information integration strategy. The current study assessed the contributions of these separate category learning systems in the context of categorical search using simple stimuli. Participants learned to classify sinusoidal grating stimuli according to explicit or implicit categorization strategies, followed by a categorical search task using these same stimulus categories. Computational modeling determined which participants used the appropriate classification strategy during training and search, and eye movements collected during categorical search were assessed. We found that the trained categorization strategies overwhelmingly transferred to the verification (classification response) phase of search. Implicit category learning led to faster search response and shorter target dwell times relative to explicit category learning, consistent with the notion that explicit rule classification relies on a more deliberative response strategy. Participants who transferred the correct category learning strategy to the search guidance phase produced stronger search guidance (defined as the proportion of trials on which the target was the first item fixated) with evidence of greater guidance in implicit-strategy learners. This demonstrates that both implicit and explicit categorization systems contribute to categorical search and produce dissociable patterns of data.
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Formação de Conceito , Aprendizagem , Humanos , Formação de Conceito/fisiologia , Aprendizagem/fisiologiaRESUMO
Purpose: Satisfaction of search (SOS) is a phenomenon where searchers are more likely to miss a lesion/target after detecting a first lesion/target. Here, we investigated SOS for masses and calcifications in virtual mammograms with experienced and novice searchers to determine the extent to which: (1) SOS affects breast lesion detection, (2) similarity between lesions impacts detection, and (3) experience impacts SOS rates. Approach: The open virtual clinical trials framework was used to simulate the breast anatomy of patients, and up to two simulated masses and/or single-calcifications were inserted into the breast models. Experienced searchers (residents, fellows, and radiologists with breast imaging experience) and novice searchers (undergraduates who had no breast imaging experience) were instructed to search for up to two lesions (masses and calcifications) per image. Results: 2×2 mixed factors analysis of variances (ANOVAs) were run with: (1) single versus second lesion hit rates, (2) similar versus dissimilar second-lesion hit rates, and (3) similar versus dissimilar second-lesion response times as within-subject factors and experience as the between subject's factor. The ANOVAs demonstrated that: (1) experienced and novice searchers made a significant amount of SOS errors, (2) similarity had little impact on experienced searchers, but novice searchers were more likely to miss a dissimilar second lesion compared to when it was similar to a detected first lesion, (3) experienced and novice searchers were faster at finding similar compared to dissimilar second lesions. Conclusions: We demonstrated that SOS is a significant cause of lesion misses in virtual mammograms and that reader experience impacts detection rates for similar compared to dissimilar abnormalities. These results suggest that experience may impact strategy and/or recognition with theoretical implications for determining why SOS occurs.
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BACKGROUND: Pancreatic cancer is the most lethal digestive cancer and the fourth overall cause of cancer death in the US. Asparagus, a widely consumed savory vegetable, is a rich source of antioxidants, saponins, vitamins, and minerals. In recent years, it has been shown that components of asparagus have anticancer effects on endometrial adenocarcinoma, and in prostate, breast, and colon cancer. In pancreatic cancer, it has been shown to have an anticancer effect on the KLM1-R cell line. This study was designed to investigate if asparagus extract (AE) had any effect on the growth of a widely used pancreatic cancer cell line MDAPanc-28 and to elucidate possible molecular mechanisms behind it. MATERIALS AND METHODS: Clonogenic survival assay, proliferation, and caspase-3 activity kits were used to evaluate the effects of AE on cell survival, proliferation, and apoptosis pathway of MDAPanc-28 cells. We further investigated the possible molecular mechanisms by using reverse transcription-polymerase chain reaction. RESULTS: The colony numbers and proliferation of MDAPanc-28 cells were surprisingly increased when treated with AE. The relative caspase-3 activity in cancer cells decreased when they were treated with AE. The pro-proliferative effect of AE on MDAPanc-28 cells correlated with down-regulation of anti-proliferative molecules P21 and P53. The potential anti-apoptotic effect of AE correlated with down-regulation of the pro-apoptotic molecule Fas cell surface death receptor (FAS) and down-regulation of caspase-3 activity. CONCLUSION: AE exhibits a pro-tumor effect on MDAPanc-28 pancreatic cancer cells by down-regulation of P21, P53, and FAS.
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Neoplasias Pancreáticas , Proteína Supressora de Tumor p53 , Apoptose , Caspase 3/metabolismo , Humanos , Masculino , Neoplasias Pancreáticas/patologia , Extratos Vegetais/farmacologia , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Neoplasias PancreáticasRESUMO
Prior target knowledge (i.e., positive cues) improves visual search performance. However, there is considerable debate about whether distractor knowledge (i.e., negative cues) can guide search. Some studies suggest the active suppression of negatively cued search items, while others suggest the initial capture of attention by negatively cued items. Prior work has used pictorial or specific text cues but has not explicitly compared them. We build on that work by comparing positive and negative cues presented pictorially and as categorical text labels using photorealistic objects and eye movement measures. Search displays contained a target (cued on positive trials), a lure from the target category (cued on negative trials), and four categorically-unrelated distractors. Search performance with positive cues resulted in stronger attentional guidance and faster object recognition for pictorial relative to categorical cues (i.e., a pictorial advantage, suggesting specific visual details afforded by pictorial cues improved search). However, in most search performance metrics, negative cues mitigate the pictorial advantage. Given that the negatively cued items captured attention, generated target guidance but mitigated the pictorial advantage, these results are partly consistent with both existing theories. Specific visual details provided in positive cues produce a large pictorial advantage in all measures, whereas specific visual details in negative cues only produce a small pictorial advantage for object recognition but not for attentional guidance. This asymmetry in the pictorial advantage suggests that the down-weighting of specific negatively cued visual features is less efficient than the up-weighting of specific positively cued visual features.
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Atenção , Sinais (Psicologia) , Movimentos Oculares , Humanos , Tempo de Reação , Percepção VisualRESUMO
Are all real-world objects created equal? Visual search difficulty increases with the number of targets and as target-related visual working memory (VWM) load increases. Our goal was to investigate the load imposed by individual real-world objects held in VWM in the context of search. Measures of visual clutter attempt to quantify real-world set-size in the context of scenes. We applied one of these measures, the number of proto-objects, to individual real-world objects and used contralateral delay activity (CDA) to measure the resulting VWM load. The current study presented a real-world object as a target cue, followed by a delay where CDA was measured. This was followed by a four-object search array. We compared CDA and later search performance from target cues containing a high or low number of proto-objects. High proto-object target cues resulted in greater CDA, longer search RTs, target dwell times, and reduced search guidance, relative to low proto-object targets. These findings demonstrate that targets with more proto-objects result in a higher VWM load and reduced search performance. This shows that the number of proto-objects contained within individual objects produce set-size like effects in VWM and suggests proto-objects may be a viable unit of measure of real-world VWM load. Importantly, this demonstrates that not all real-world objects are created equal.
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Potenciais Evocados , Memória de Curto Prazo , Sinais (Psicologia) , Humanos , Percepção VisualRESUMO
For over 50 years, the satisfaction of search effect has been studied within the field of radiology. Defined as a decrease in detection rates for a subsequent target when an initial target is found within the image, these multiple target errors are known to underlie errors of omission (e.g., a radiologist is more likely to miss an abnormality if another abnormality is identified). More recently, they have also been found to underlie lab-based search errors in cognitive science experiments (e.g., an observer is more likely to miss a target 'T' if a different target 'T' was detected). This phenomenon was renamed the subsequent search miss (SSM) effect in cognitive science. Here we review the SSM literature in both radiology and cognitive science and discuss: (1) the current SSM theories (i.e., satisfaction, perceptual set, and resource depletion theories), (2) the eye movement errors that underlie the SSM effect, (3) the existing efforts tested to alleviate SSM errors, and (4) the evolution of methodologies and analyses used when calculating the SSM effect. Finally, we present the attentional template theory, a novel mechanistic explanation for SSM errors, which ties together our current understanding of SSM errors and the attentional template literature.
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Satisfação Pessoal , Radiologia , Atenção , Ciência Cognitiva , Movimentos OcularesRESUMO
OBJECTIVES: Negative psychiatric symptoms are often resistant to treatments, regardless of the disorder in which they appear. One model for a cause of negative symptoms is impairment in higher-order cognition. The current study examined how particular bottom-up and top-down mechanisms of selective attention relate to severity of negative symptoms across a transdiagnostic psychiatric sample. METHODS: The sample consisted of 130 participants: 25 schizophrenia-spectrum disorders, 26 bipolar disorders, 18 unipolar depression, and 61 nonpsychiatric controls. The relationships between attentional event-related potentials following rare visual targets (i.e., N1, N2b, P2a, and P3b) and severity of the negative symptom domains of anhedonia, avolition, and blunted affect were evaluated using frequentist and Bayesian analyses. RESULTS: P3b and N2b mean amplitudes were inversely related to the Positive and Negative Syndrome Scale-Negative Symptom Factor severity score across the entire sample. Subsequent regression analyses showed a significant negative transdiagnostic relationship between P3b amplitude and blunted affect severity. CONCLUSIONS: Results indicate that negative symptoms, and particularly blunted affect, may have a stronger association with deficits in top-down mechanisms of selective attention. SIGNIFICANCE: This suggests that people with greater severity of blunted affect, independent of diagnosis, do not allocate sufficient cognitive resources when engaging in activities requiring selective attention.
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Potenciais Evocados Visuais/fisiologia , Transtornos Mentais/diagnóstico , Transtornos Mentais/fisiopatologia , Estimulação Luminosa/métodos , Índice de Gravidade de Doença , Adulto , Feminino , Humanos , Masculino , Transtornos Mentais/psicologia , Pessoa de Meia-Idade , Adulto JovemRESUMO
One in 113-178 females worldwide carry a premutation allele on the FMR1 gene. The FMR1 premutation is linked to neurocognitive and neuromotor impairments, although the phenotype is not fully understood, particularly with respect to age effects. This study sought to define oculomotor response inhibition skills in women with the FMR1 premutation and their association with age and fall risk. We employed an antisaccade eye-tracking paradigm to index oculomotor inhibition skills in 35 women with the FMR1 premutation and 28 control women. The FMR1 premutation group exhibited longer antisaccade latency and reduced accuracy relative to controls, indicating deficient response inhibition skills. Longer response latency was associated with older age in the FMR1 premutation and was also predictive of fall risk. Findings highlight the utility of the antisaccade paradigm for detecting early signs of age-related executive decline in the FMR1 premutation, which is related to fall risk. Findings support the need for clinical prevention efforts to decrease and delay the trajectory of age-related executive decline in women with the FMR1 premutation during midlife.
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Proteína do X Frágil da Deficiência Intelectual , Síndrome do Cromossomo X Frágil , Idoso , Ataxia , Feminino , Proteína do X Frágil da Deficiência Intelectual/genética , Heterozigoto , Humanos , TremorRESUMO
This work presents a novel method of exploring human brain-visual representations, with a view towards replicating these processes in machines. The core idea is to learn plausible computational and biological representations by correlating human neural activity and natural images. Thus, we first propose a model, EEG-ChannelNet, to learn a brain manifold for EEG classification. After verifying that visual information can be extracted from EEG data, we introduce a multimodal approach that uses deep image and EEG encoders, trained in a siamese configuration, for learning a joint manifold that maximizes a compatibility measure between visual features and brain representations. We then carry out image classification and saliency detection on the learned manifold. Performance analyses show that our approach satisfactorily decodes visual information from neural signals. This, in turn, can be used to effectively supervise the training of deep learning models, as demonstrated by the high performance of image classification and saliency detection on out-of-training classes. The obtained results show that the learned brain-visual features lead to improved performance and simultaneously bring deep models more in line with cognitive neuroscience work related to visual perception and attention.
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Algoritmos , Redes Neurais de Computação , Atenção , Encéfalo/diagnóstico por imagem , Humanos , Percepção VisualRESUMO
A high-yielding and atom-efficient protocol for the double hydrophosphorylation of nitriles using a lanthanum-based N,N-dimethylbenzylamine complex (La(DMBA)3) as a precatalyst is reported. This method provides a straightforward and convenient approach for the synthesis of biologically important organophosphorus compounds known as N-(α-phosphoryl)amidophosphates in good to excellent yields. Nitriles with a broad range of additional functionality were tolerated, including those with halides, ethers, amines, and pyridyl groups.
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INTRODUCTION: Delays in patient flow in the emergency department (ED) result in patients leaving without being seen (LWBS). This compromises patient experience and quality of care. Our primary goal was to develop a predictive model by evaluating associations between patients LWBS and ED process measures and patient characteristics. METHODS: This was a cross-sectional study in a 95,000 annual visit adult ED comparing patients LWBS, with controls. Data were drawn from four seasonally adjusted four-week periods (30,679 total visits). Process measures included 1) arrivals per hour; 2) "door-to-provider" time; and the numbers of 3) patients in the waiting room; 4) boarding ED patients waiting for an inpatient bed; 5) providers and nurses (RN); and 6) patients per RN. Patient characteristics collected included 1) age; 2) gender; 3) race/ethnicity; 4) arrival mode (walk-in or via emergency medical services [EMS]); and 5) acuity based on Emergency Severity Index (ESI). Univariable analyses included t-tests and Pearson's chi-square tests. We split the data randomly into derivation and validation cohorts. We used backward selection to develop the final derivation model, and factors with a p-value ≤ 0.05 were retained. Estimates were applied to the validation cohort and measures of discrimination (receiver operating characteristic) and model fit were assessed. RESULTS: In the final model, the odds of LWBS increased with the number of patients in the waiting room (odds ratio [OR] 1.05; 95% confidence interval [CI], 1.03 to 1.06); number of boarding patients (OR 1.02; 95% CI, 1.01 to 1.03); arrival rate (OR 1.04; 95% CI, 1.02 to 1.05) and longer "door-to-provider" times (test of linear trend in the adjusted OR was p = 0.002). Patient characteristics associated with LWBS included younger age (OR 0.98; 95% CI, 0.98 to 0.99), and lower acuity (higher ESI category) (OR 2.01; 95% CI, 1.84 to 2.20). Arrival by EMS was inversely associated with LWBS (OR 0.29; 0.23 to 0.36). The area under the curve for the final model in the validation cohort was 0.85 (95% CI, 0.84 to 0.86). There was good agreement between the observed and predicted risk. CONCLUSION: Arrival rate, "door-to-provider time," and the numbers of patients in the waiting room and ED boarders are all associated with patients LWBS.
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Serviços Médicos de Emergência/organização & administração , Serviço Hospitalar de Emergência/estatística & dados numéricos , Admissão do Paciente/estatística & dados numéricos , Pacientes Desistentes do Tratamento/estatística & dados numéricos , Pacientes/psicologia , Qualidade da Assistência à Saúde , Tempo para o Tratamento/estatística & dados numéricos , Recusa do Paciente ao Tratamento/estatística & dados numéricos , Triagem/métodos , Salas de Espera , Adulto , Estudos de Casos e Controles , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Pacientes/estatística & dados numéricosRESUMO
Pictorial cues generally produce stronger search performance relative to categorical cues. We asked how universal is the benefit of a pictorial cue? To test this, we trained observers to categorize sinusoidal gratings in which categories were distinguished by spatial frequency or orientation. Next, participants completed a search task in which targets were pictorially and categorically cued. Measures of target and distractor processing that primarily rely on foveal processing showed universal benefits; however, the benefit was larger in the orientation condition. Importantly, an index of the direction of spatial attention (i.e., target guidance) showed that the orientation condition produced a pictorial benefit but the spatial frequency condition did not. Experiment 2 replicated the spatial frequency results and also included conditions that increased the discriminability, lowered the spatial frequencies, or both increased the discriminability and decreased the spatial frequencies of the categories. We found that only categories utilizing lower spatial frequencies produced a pictorial guidance benefit. This demonstrates that pictorial cues do not universally improve search performance above categorical cues; it depends on the features that distinguish the categories. Additionally, the increased discriminability condition improved guidance but failed to produce a pictorial benefit, suggesting an interesting disassociation between the amount of target guidance and the existence of a pictorial benefit. Given that perception is known to progress from low/coarse to high/fine spatial frequencies, this suggests that the pictorial guidance benefit acts on early low-spatial frequency processing only, but foveal object recognition processes utilize both early and late spatial frequency processing.
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Atenção , Sinais (Psicologia) , Humanos , Orientação , Orientação Espacial , Reconhecimento Visual de Modelos , Tempo de Reação , Percepção VisualRESUMO
Incomplete block designs are experimental designs in which a subset of treatments are included in each block. The researcher must decide which conditions are assigned to each block. This design concept is quite general. At the level of the experiment, a treatment is a condition in an experiment, blocks are different groups of subjects, and the researcher must decide how to assign a subset of conditions to each block of subjects. At the level of the subject, the treatments correspond to individual stimuli, blocks correspond to experimental trials, and the researcher must decide which subset of stimuli to include in each trial. In this article, we present an efficient algorithm that assigns treatments to blocks in an incomplete block design according to two criteria: Each pair of treatments must appear together in at least one block, and the number of blocks in the experiment is minimized. We discuss details and applications of the algorithm and provide software and a web application to generate designs according to the needs of the researcher.
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Algoritmos , Software , Humanos , Projetos de PesquisaRESUMO
Fragile X syndrome (FXS) is characterized by hallmark features of gaze avoidance, reduced social approach, and social anxiety. The development of therapeutics to manage these symptoms has been hindered, in part, by the lack of sensitive outcome measures. This study investigated the utility of a novel eye-tracking paradigm for indexing social avoidance-related phenotypes. Adolescent/young adult-aged males with FXS (n = 24) and typical development (n = 23) participated in the study. Participants viewed faces displaying direct or averted gaze and the first fixation duration on the eyes was recorded as an index of initial stimulus registration. Fixation durations did not differ across the direction of gaze conditions in either group, although the control group showed longer initial fixations on the eyes relative to the FXS group. Shorter initial fixation on averted gaze in males with FXS was a robust predictor of the severity of their social avoidance behavior exhibited during a social greeting context, whereas parent-reported social avoidance symptoms were not related to performance in the semi-naturalistic context. This eye-tracking paradigm may represent a promising outcome measure for FXS clinical trials because it provides a quantitative index that closely maps onto core social avoidance phenotypes of FXS, can be completed in less than 20 min, and is suitable for use with individuals with low IQ.
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Aprendizagem da Esquiva/fisiologia , Tecnologia de Rastreamento Ocular/psicologia , Síndrome do Cromossomo X Frágil/fisiopatologia , Adolescente , Adulto , Medições dos Movimentos Oculares/psicologia , Movimentos Oculares/fisiologia , Expressão Facial , Humanos , Masculino , Comportamento Social , Adulto JovemRESUMO
We develop competing hypotheses about the relationship between high performance work systems (HPWS) with employee and customer satisfaction. Drawing on 8 years of employee and customer survey data from a financial services firm, we used a recently developed empirical technique-covariate balanced propensity score (CBPS) weighting-to examine if the proposed relationships between HPWS and satisfaction outcomes can be explained by reverse causality, selection effects, or commonly omitted variables such as leadership behavior. The results provide support for leader behaviors as a primary driver of customer satisfaction, rather than HPWS, and also suggest that the problem of reverse causality requires additional attention in future human resource (HR) systems research. Model comparisons suggest that the estimates and conclusions vary across CBPS, meta-analytic, cross-sectional, and time-lagged models (with and without a lagged dependent variable as a control). We highlight the theoretical and methodological implications of the findings for HR systems research. (PsycINFO Database Record
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Comportamento do Consumidor , Satisfação no Emprego , Liderança , Viés de Seleção , Desenvolvimento de Pessoal/tendências , Emprego/psicologia , Feminino , Humanos , Masculino , Modelos Econométricos , Cultura Organizacional , Projetos de Pesquisa , Desempenho Profissional , Local de Trabalho/psicologiaRESUMO
A reduced P1 visual-evoked potential amplitude has been reported across several psychiatric disorders, including schizophrenia-spectrum, bipolar, and depressive disorders. In addition, a difference in P1 amplitude change to a red background compared to its opponent color, green, has been found in schizophrenia-spectrum samples. The current study examined whether specific psychiatric symptoms that related to these P1 abnormalities in earlier studies would be replicated when using a broad transdiagnostic sample. The final sample consisted of 135 participants: 26 with bipolar disorders, 25 with schizophrenia-spectrum disorders, 19 with unipolar depression, 62 with no current psychiatric disorder, and 3 with disorders in other categories. Low (8%) and high (64%) contrast check arrays were presented on gray, green, and red background conditions during electroencephalogram, while an eye tracker monitored visual fixation on the stimuli. Linear regressions across the entire sample (Nâ¯=â¯135) found that greater severity of both clinician-rated and self-reported delusions/magical thinking correlated with a reduced P1 amplitude on the low contrast gray (neutral) background condition. In addition, across the entire sample, higher self-reported constricted affect was associated with a larger decrease in P1 amplitude (averaged across contrast conditions) to the red, compared to green, background. All relationships remained statistically significant after covarying for diagnostic class, suggesting that they are relatively transdiagnostic in nature. These findings indicate that early visual processing abnormalities may be more directly related to specific transdiagnostic symptoms such as delusions and constricted affect rather than specific psychiatric diagnoses or broad symptom factor scales.
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Cor , Transtorno Depressivo Maior/diagnóstico , Transtorno Depressivo Maior/fisiopatologia , Potenciais Evocados Visuais/fisiologia , Esquizofrenia/diagnóstico , Esquizofrenia/fisiopatologia , Adulto , Mapeamento Encefálico , Transtorno Depressivo Maior/psicologia , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa , Escalas de Graduação Psiquiátrica , Psicometria , Tempo de Reação/fisiologia , Psicologia do Esquizofrênico , Adulto JovemRESUMO
Background: Neurotypical young adults show task-based modulation and stability of their eye movements across tasks. This study aimed to determine whether persons with aphasia (PWA) modulate their eye movements and show stability across tasks similarly to control participants. Methods: Forty-eight PWA and age-matched control participants completed four eye-tracking tasks: scene search, scene memorization, text-reading, and pseudo-reading. Results: Main effects of task emerged for mean fixation duration, saccade amplitude, and standard deviations of each, demonstrating task-based modulation of eye movements. Group by task interactions indicated that PWA produced shorter fixations relative to controls. This effect was most pronounced for scene memorization and for individuals who recently suffered a stroke. PWA produced longer fixations, shorter saccades, and less variable eye movements in reading tasks compared to controls. Three-way interactions of group, aphasia subtype, and task also emerged. Text-reading and scene memorization were particularly effective at distinguishing aphasia subtype. Persons with anomic aphasia showed a reduction in reading saccade amplitudes relative to their respective control group and other PWA. Persons with conduction/Wernicke's aphasia produced shorter scene memorization fixations relative to controls or PWA of other subtypes, suggesting a memorization specific effect. Positive correlations across most tasks emerged for fixation duration and did not significantly differ between controls and PWA. Conclusion: PWA generally produced shorter fixations and smaller saccades relative to controls particularly in scene memorization and text-reading, respectively. The effect was most pronounced recently after a stroke. Selectively in reading tasks, PWA produced longer fixations and shorter saccades relative to controls, consistent with reading difficulty. PWA showed task-based modulation of eye movements, though the pattern of results was somewhat abnormal relative to controls. All subtypes of PWA also demonstrated task-based modulation of eye movements. However, persons with anomic aphasia showed reduced modulation of saccade amplitude and smaller reading saccades, possibly to improve reading comprehension. Controls and PWA generally produced stabile fixation durations across tasks and did not differ in their relationship across tasks. Overall, these results suggest there is potential to differentiate among PWA with varying subtypes and from controls using eye movement measures of task-based modulation, especially reading and scene memorization tasks.
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BACKGROUND: The percentage of patients who leave the emergency department without being seen by a provider is a measure of efficiency and presents risk-management concerns. The number of patients actually "seen" by a provider is a measure of productivity. The opening of our new emergency department in December 2012, resulted in increases in both demand and the percentage of patients who left without being seen. Operational nursing leadership managed ED patient flow, but the structure was loosely organized on an ad hoc basis. METHODS: Operational nursing leadership roles were re-assigned to personnel with management aptitude and interest. The charge nurse coordinated care throughout all sections (pods) of the department while the pod lead nurse coordinated care in each pod. The flow coordinator nurse accepted transfers and emergency medical services arrivals. Nursing and physician staffing remained unchanged, and measures were calculated over a 3-year period (December 3, 2012, to December 2, 2015). The number of patients seen per day was analyzed using simple linear regression. The percentage of patients who left without being seen was analyzed using fractional logistic regression; P< 0.05 was considered statistically significant. RESULTS: The weekly mean number of patients seen per day rose 13% from 265 to 299 patients. The weekly mean percentage of patients who left without being seen declined 45% from 8.2% to 4.5%. The regression lines for both measures were significant at P < 0.001. CONCLUSION: Measures of efficiency and productivity can be improved significantly with a dedicated operational nursing leadership structure without adding nursing or physician staffing.