Interactions between subjective memory complaint and objective cognitive deficit on memory performances

Background Subjective memory complaint (SMCs) is a common trait amongst older population. The subjective cognition about their memory could depend on objective cognition. The aim of the current study was to examine the interaction between subjective memory cognition (i.e., SMC) and objective cognition on cognitive functions in participants from older generation. Methods A total of 219 patients, 181 normal control (NC) patients and 38 patients with mild cognitive impairment (MCI), were examined through standardized and comprehensive clinical evaluation and neuropsychological assessment. The Subjective Memory Complaints Questionnaire was used to assess SMCs along with five cognitive tasks were used to evaluate cognitive decline over following areas: verbal memory, visuospatial memory, attention, fluency, and language. Results The results of 2 × 2 two-way analysis of variance (ANOVA) showed that there were significant interactions between SMCs and cognitive status (NC, MCI) on memory performances. NC with SMCs showed significantly lower performance in verbal memory and visuospatial memory compared to NCs without SMCs. Conversely, no effect was observed in the MCI group. Conclusion There are interactions between subjective cognition (i.e., SMC) and objective cognition (i.e., cognitive status) on memory performances in older adults. The roles of SMCs on memory performances should be interpreted with older adults objective cognitive status.This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. NRF-2017R1D1A1A02018479). This funding source had no role in the design of this study and will not have any role during its execution, analyses, interpretation of the data, or decision to submit result

Impact of seasonal vertical stratification on the dispersion patterns of dredging plumes off the south coast of Korea

Simultaneous satellite and ship-borne surveys have been conducted to investigate the dispersion patterns of dredging plumes off the south coast of Korea in two contrasting seasons (spring and autumn). The distribution of total suspended solid (TSS) derived from sequential satellite imagery showed that the dredging plumes in spring developed over longer distances along the surface current than those in autumn. In spring, the deep and strong stratified condition in the water column contributed to the increase in radius of plume dispersion along the water surface. In autumn, the shallow and vertically well-mixed (or un-stratified) condition in the water column enhanced sinking of suspended dredged materials. This difference is due to the Brunt-Vaisala frequency being higher in spring (0.0183 s(-1)) than in autumn (0.0123 s(-1)). Although the sediment-laden overflow significantly increased TSS near the surface during the dredging period, the TSS contribution to water column stratification was only 23-5.6% of the thermohaline contribution. Therefore, the seasonal variation of thermohaline density is the main factor determining the dispersion patterns of dredging plumes in the study area