This study examines the extent to which infrequent changes in the intensity of an auditory stimulus can interrupt the functioning of the central executive during natural sleep. In the waking, conscious state, highly relevant but unattended stimulus input may elicit a positive-going event-related potential, P3a, peaking at about 250 ms. P3a is presumed to reflect the interruption of the central executive controlling ongoing cognitive activities, resulting in potential awareness of stimulus input. In this study, both an increment and decrement in the intensity of a frequently occurring standard stimulus elicited a P3a during wakefulness. During Rapid Eye Movement sleep, only the increment continued to do so. Detection of an increase in the intensity of a standard stimulus is thought to be carried out by two separate systems, the transient detector system (responsible for the detection of transient energy) and the change detection system. By contrast, detection of a decrease in intensity is carried out only by the change detection system. This suggests that interruption of central executive functioning during Rapid Eye Movement is largely a consequence of sufficient output of the auditory transient detector rather than the change detector system. During stage 2, neither the decrement nor the increment was able to elicit a P3a. This is consistent with a deactivation of the central executive and a profound state of unconsciousness.

The present study evaluated the use of slow rates of stimulus presentation on the accuracy of the N1-P2 cortical response in estimating hearing threshold. Long interstimulus intervals (ISI) allow the non-specific component of the N1 response to emerge, believed to reflect widespread cortical arousal that facilitates sensory and motor responses. We examined whether the non-specific N1 would be elicited at intensity levels near threshold. Event-related potentials were recorded to 0.5-, 1.0, and 4.0-kHz tone bursts with a long ISI (8-12 s) while the eleven subjects read a book. The stimulus level varied from -5 to 45 dB nHL. The 1.0-kHz tone burst was also presented with a shorter ISI (1.5-2.5 s), akin to that typically used in the audiological setting. The amplitude of N1-P2 was significantly enhanced in the long compared to short ISI condition, but, importantly, only for the stimuli with a level > or =25 dB nHL. Therefore, the N1-P2 recorded with long ISIs was not more precise in estimating threshold than that recorded with short ISIs, remaining visible to within 10 dB of behavioural threshold.

Background: Glomerular filtration rate (GFR) is a valid indicator of kidney function. Different factors can affect GFR. The purpose of this study is to assess the direct and indirect effects of GFR-related factors using structural equation modeling. Patients and methods: We analyzed data from the baseline phase of the Ravansar Non-Communicable Disease cohort study. Data on socio-behavioral, nutritional, cardiovascular, and metabolic risk factors were analyzed using a conceptual model in order to test direct and indirect effects of factors related to GFR, separately in male and female, using the structural equation modeling. Results: Of 8927 individuals who participated in this study, 4212 subjects were male (47.20%). The mean and standard deviation of GFR was 76.05 (±14.31) per 1.73 m 2. GFR for 0.2, 11.3, 73.0 and 15.5% of people were < 30, 30 − 59, 60 − 90 and >90, respectively. Hypertension and aging in both sexes and atherogenic factor in males directly, and in females, directly and indirectly, had decreasing effects on GFR. Blood urea nitrogen and smoking in male and female, directly or indirectly through other variables, were associated with a lower GFR. In females, diabetes had a direct and indirect decreasing effect on GFR. Obesity in females was directly associated with upper and indirectly associated with lower GFR. Conclusion: According to our results, aging, hypertension, diabetes, obesity, high lipid profile, and BUN had a decreasing direct and indirect effect on GFR. Although low GFR might have different reasons, our findings, are in line with other reports and provide more detailed information about important risk factors of low GFR. Public awareness of such factors can improve practice of positive health behaviors.

Background: glomerular filtration rate (GFR) is a valid indicator for kidney function. Different factors can affect GFR. The purpose of this study is to assess direct and indirect effects of GFR-related factors using structural equation modeling.Patients and methods:We analyzed data from baseline phase of Ravansar Non-Communicable Disease cohort study. Data on socio-behavioral, nutritional, cardiovascular, and metabolic risk factors were entered in a conceptual model in order to test direct and indirect effects of factors related to GFR,separately in male and female, using the structural equation modeling.Results: Of 8927 individuals participated in this study, 4212 subjects were male (47.20%) and 4715 subjects were female (52.80%). The obtained mean and standard deviation of GFR was 76.05 (±14.31) per 1.73 . GFR for 0.2%, 11.3%, 73.0% and 15.50% of people were <30, , and , respectively. Hypertension and aging in both gender and atherogenic factor in male directly, and in female directly and indirectly had a lower effect on GFR. Blood urea nitrogen and smoking in male and female, directly or indirectly through other variables, were associated with a lower GFR. In female, diabetes had a lower direct and indirect effect on GFR. Obesity in female was directly associated with uper and indirectly associated with lower GFR.Conclusion: According to our results, aging, hypertension, diabetes, obesity and high lipid profile, and BUN had a decreasing direct and indirect effects on GFR. Although low GFR might have different reasons and it is not a consistent sign of CKD, our findings, are in line with other reports, provide more detailed informations about important risk factors of low GFR. Public awareness about such factors can improve public practice of positive health behaviours.

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