In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Q: Context: To examine peripheral nerve stimulation (PNS) thresholds for normal human subjects in magnetic resonance imaging (MRI) gradient coils, and determine if observed thresholds could be predicted based on gross physiologic measurements.', 'PNS thresholds for 21 healthy normal subjects were measured using a whole-body gradient coil. Subjects were exposed to a trapezoidal echo-planar imaging (EPI) gradient waveform and the total change in gradient strength (DeltaG) required to cause PNS as a function of the duration of the gradient switching time (tau) were measured. Correlation coefficients and corresponding P values were calculated for the PNS threshold measurements against simple physiologic measurements taken of the subjects, including weight, height, girth, and average body fat percentage, in order to determine if there were any easily observable dependencies.', 'No convincing correlations between threshold parameters and gross physiologic measurements were observed.\Question: Do simple anatomical measurements correlate significantly to individual peripheral nerve stimulation thresholds as measured in MRI gradient coils?

A: These results suggest it is unlikely that a simple physiologic measurement of subject anatomy can be used to guide the operation of MRI scanners in a subject-specific manner in order to increase gradient system performance while avoiding PNS.
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Q: Context: The measurement of affective symptoms in older persons who decline cognitively is uncertain. The authors investigated whether mood variability predicts dementia in patients with age-related macular degeneration (AMD).', 'Three-year observational study after a clinical trial.', 'Community follow-up of outpatients ascertained from retina clinics.', 'One hundred sixty patients with AMD.', "Geriatric Depression Scale (GDS) administered every 2 weeks for 6 months to subjects; Informant Questionnaire for Cognitive Decline in the Elderly (IQCODE) administered to subjects' knowledgeable informants.", 'Twenty-three subjects (14.4%) declined cognitively. Age, education, baseline GDS score > or =5, and variability in GDS scores (i.e., fluctuations between adjacent time points) were associated with cognitive decline. For GDS variability, each 1 unit increase in the residual standard deviation (SD) of the GDS increased the risk for cognitive decline by 93% (IDR = 1.92; 95% CI [1.27-2.91]). Thus, subjects with a residual SD of 1 were nearly twice as likely to become demented as subjects with no variability in GDS scores. The risk for subjects with SDs of 2 increased more than threefold (IDR = 3.68; 95% CI [1.61-8.47]). A multiple regression analysis showed that GDS variability was a significant risk factor for dementia after controlling for significant covariates.\Question: Does variability in depressive symptoms predict cognitive decline in age-related macular degeneration?

A: These data suggest a useful approach to conceptualizing and measuring depressive symptoms in older persons. Variability in self-reported mood may be an early sign of dementia and may offer new insights into the neurobiological mechanisms linking depression and cognition
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Q: Context: The incidence and predictors of spontaneous hepatitis B surface-antigen (HBsAg) seroclearance in patients with chronic hepatitis B virus (HBV) were evaluated.', 'A total of 1427 patients with chronic HBV infection, who were followed between 1994 and 2013, were investigated in this retrospective study. All data were extracted from patient files.', 'Spontaneous HBsAg seroclearance occurred in 84 patients during 8798 person-years of follow-up. The patients were categorized into 3 groups at follow-up based on HBV DNA features as continuously <100 copies/mL (Group A), 0-10,000 copies/mL (Group B), and 0 to >10,000 copies/mL (Group C). Alanine aminotransferase features in the 2 groups were categorized as continuously normal (<40 U/L) and 0 to >40 U/L. Spontaneous HBsAg seroclearance was seen primarily in patients with Group A HBV DNA features, and continuously low HBV DNA values were the main predictor of HBsAg seroclearance (P < 0.001).\Question: Is a persistently low HBV DNA level a predictor of spontaneous HBsAg clearance in patients with chronic hepatitis B?

A:
These results suggest that a continuously low viral load is the most important factor affecting spontaneous HBsAg seroclearance.
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