Search

Numerals are part of our everyday lives and are regularly viewed in less-than ideal conditions. Mistaking one numeral for another is almost an inevitability, and the cost of these confusions could be insignificant or hugely expensive! Numeral confusions can be explained by distances between our mental representations — how we internally represent the external world — resulting from their perceived similarities; yet, how expertise interacts with the mental space of numerals is largely unexplored. We used an identification paradigm to investigate the mental representations of familiar and unfamiliar numerals (4 sets: Arabic, Chinese, Thai, and non-symbolic dots) in a first-language English and a first-language Chinese speaking cohort. Using Luce's choice model, we removed the undesired effect of response bias and conducted multidimensional scaling analyses. Results showed that expertise with numerals alters distances in the mental space, that unfamiliar numerals are represented identically across cultures, that non-symbolic numerals (dots) may be represented both perceptually and numerically in the mental space, and that Arabic, Thai and Chinese numerals are represented by their perceptual similarities. The findings and methods of this study provide a principled foundation for future investigations into how expertise shapes people's mental representations.

ObjectiveWe have designed tracking and collision prediction tasks to elucidate the differences in the physiological response to the workload variations in basic ATC tasks to untangle the impact of workload variations experienced by operators working in a complex ATC environment.BackgroundEven though several factors influence the complexity of ATC tasks, keeping track of the aircraft and preventing collision are the most crucial.MethodsPhysiological measures, such as electroencephalogram (EEG), eye activity, and heart rate variability (HRV) data, were recorded from 24 participants performing tracking and collision prediction tasks with three levels of difficulty.ResultsThe neurometrics of workload variations in the tracking and collision prediction tasks were markedly distinct, indicating that neurometrics can provide insights on the type of mental workload. The pupil size, number of blinks and HRV metric, root mean square of successive difference (RMSSD), varied significantly with the mental workload in both these tasks in a similar manner.ConclusionOur findings indicate that variations in task load are sensitively reflected in physiological signals, such as EEG, eye activity and HRV, in these basic ATC-related tasks.ApplicationThese findings have applicability to the design of future mental workload adaptive systems that integrate neurometrics in deciding not just ‘when’ but also ‘what’ to adapt. Our study provides compelling evidence in the viability of developing intelligent closed-loop mental workload adaptive systems that ensure efficiency and safety in ATC and beyond.PrécisThis article identifies the physiological correlates of mental workload variation in basic ATC tasks. The findings assert that neurometrics can provide more information on the task that contributes to the workload, which can aid in the design of intelligent mental workload adaptive system.

People express quantities using a remarkably small set of units – digits. Confusing digits could be costly, and not all confusions are equal; confusing a price tag of 2 dollars with 9 dollars is naturally more costly than confusing 2 with 3. Confusion patterns are intimately related to the distances between mental representations, which are hypothetical internal symbols said to stand for, or represent, ‘real’ external stimuli. The distance between the mental representations of two digits could be determined by their numerical distance. Alternatively, it could be driven by visual similarity. In an English speaking cohort, we investigated the mental representations of familiar and unfamiliar numbers (4 sets: Arabic, Chinese, Thai, and non-symbolic dots) through a set of identification experiments, using multi-dimensional scaling and cluster analysis. We controlled for undesired effects of response bias using Luce’s choice model. Our findings show Arabic, Chinese and Thai numerals were represented in the mental space by perceptual similarities. We also find non-symbolic dots were represented by perceptual and numerical similarities. This work is a novel contribution to the literature and lays the foundation for further investigations into the mental representation of numerals across cultures.

Ohmic contacts to n-type crystalline silicon created by local laser firing was studied in this paper. A novel metal stack of Al-Sb-Ti was fired through a dielectric layer or opposite doped amorphous silicon layer. Specific contact resistances of less than 1.9 mΩcm2 and 0.31 mΩcm2 using a pseudo transfer length method and a vertical test structure, respectively, are demonstrated. Recombination loss due to laser damage was consistent with an extracted local Surface Recombination Velocity (SRV) ~20,000 cm/s similar to values for laser fired base contact for p-type crystalline silicon. Hetero-junction devices were fabricated with laser fired back contact and proof-of-concept efficiencies of 14.4% on front silicon hetero-junction and 13.1% on interdigitated back contact silicon hetero-junction (IBC-SHJ) cells were achieved. This localized base contact technique will enable low cost back contact patterning and innovative design for n type crystalline solar cells.

Knowledge about the characteristics of patients using psychiatric emergency services is expanding. However, the prevalence of HIV infection among patients treated at psychiatric emergency departments is not known, and neither are the characteristics of HIV-positive patients seen in this setting.To estimate the prevalence and demographic and clinical correlates of HIV infection among patients utilizing psychiatric emergency services in a level 1 trauma center, the authors analyzed data from a series of 58,301 consecutive visits (28,817 unique patients).Of the total psychiatric emergency visits, 2.0% were by HIV-positive patients, who were more likely to be male, homeless, or African American. These patients were also more likely to show dementia or to be suicidal, abusing substances, or coping with borderline personality disorder.More precise description of HIV-positive patients visiting psychiatric emergency departments may help elucidate the needs of this population and help plan for improvements in care in this setting.

GHB is an increasingly popular drug of abuse that can be associated in select cases with growing dependence and a severe withdrawal syndrome. While benzodiazepines are recommended for treatment of the withdrawal syndrome, some cases have been described as benzodiazepine-resistant. The authors describe treatment of such a case, which was unsuccessfully treated initially with benzodiazepines, then successfully treated with adjuvant atypical neuroleptics, and offer a possible neurochemical explanation for why such agents may be theoretically more effective than benzodiazepines in treating GHB withdrawal.

OBJECTIVE The objective of this study was to replicate the relationship between disclosure of sexual orientation and immune functioning in HIV-positive persons and to extend those findings to a different type of disclosure (HIV status) and a different population (psychiatric outpatients in a publicly funded HIV/AIDS clinic). METHODS A sample of psychiatric outpatients (N = 373) from a large, urban HIV clinic was assessed for level of sexual orientation and HIV status disclosure as well as absolute CD4 cell counts over time. Mixed-effects random regression analysis was used to build a predictor model that included biobehavioral covariates. RESULTS Consistent disclosure of both sexual orientation and HIV status independently predicted increased CD4 cell counts over time controlling for important biobehavioral covariates. The only other significant effects in the model were baseline CD4 cell count and number of days between assessment of disclosure and assessment of CD4 cell count. CONCLUSIONS Relieving potential psychological distress by disclosing sexual orientation and HIV status has a positive impact on CD4 cell counts over time even among outpatients stressed by psychiatric illness and economic disadvantage. Additional research is needed to understand whether and under what conditions disclosure should be part of HIV disease management.