How does Stock Market Liquidity Forecast Economic Growth?

This paper examines the relationship between stock market liquidity and the real economy in Korea during the period 1995:2–2011:4. We find that stock market liquidity is positively and significantly correlated with future economic growth. Specifically, we find that the Amihud (2002) illiquidity measure is a good predictor of the next quarter’s real GDP growth. We also find that the illiquidity of small, young, non-dividend-paying, and distressed firms, which are more likely to be informationally opaque and difficult to arbitrage, is more informative when predicting future economic downturns. From the perspective of the flight to quality, the implication is that investors shift their portfolios toward safe assets when they expect the economy to be in trouble. Keywords: Korean stock market, Economic development, Firm characteristic

Performance analysis of polling systems with retrials and glue periods

We consider gated polling systems with two special features: (i) retrials, and (ii) glue or reservation periods. When a type-$i$ customer arrives, or retries, during a glue period of station $i$, it will be served in the next visit period of the server to that station. Customers arriving at station $i$ in any other period join the orbit of that station and retry after an exponentially distributed time. Such polling systems can be used to study the performance of certain switches in optical communication systems. For the case of exponentially distributed glue periods, we present an algorithm to obtain the moments of the number of customers in each station. For generally distributed glue periods, we consider the distribution of the total workload in the system, using it to derive a pseudo conservation law which in its turn is used to obtain accurate approximations of the individual mean waiting times. We also consider the problem of choosing the lengths of the glue periods, under a constraint on the total glue period per cycle, so as to minimize a weighted sum of the mean waiting times

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

Stock market reaction to US interest rate hike: evidence from an emerging market

This paper investigates how a developing stock market responds to US interest rate increases, using Korean firm data. We find that the Fed's sharp rate hike causes the flight to quality of investors in the emerging market. Furthermore, firms with more export sales, higher foreign ownership, and larger market capitalization outperform during a US interest rate shock. We also find that financial flexibility is particularly valuable for small-cap firms when the US aggressively raises interest rates

Slowdown in the M/M/1M/M/1 discriminatory processor-sharing queue

We consider a queue with multiple K job classes, Poisson arrivals, and exponentially distributed required service times in which a single processor serves according to the discriminatory processor-sharing (DPS) discipline. For this queue, we obtain the first and second moments of the slowdown, which is a measure for queueing fairness. We then provide numerical examples and discuss aspects of the slowdown in the DPS queue

Performance analysis of polling systems with retrials and glue periods

Abstract\u3cbr/\u3e\u3cbr/\u3eWe consider gated polling systems with two special features: (i) retrials and (ii) glue or reservation periods. When a type-i customer arrives, or retries, during a glue period of the station i, it will be served in the following service period of that station. Customers arriving at station i in any other period join the orbit of that station and will retry after an exponentially distributed time. Such polling systems can be used to study the performance of certain switches in optical communication systems. When the glue periods are exponentially distributed, we obtain equations for the joint generating functions of the number of customers in each station. We also present an algorithm to obtain the moments of the number of customers in each station. When the glue periods are generally distributed, we consider the distribution of the total workload in the system, using it to derive a pseudo-conservation law which in turn is used to obtain accurate approximations of the individual mean waiting times. We also investigate the problem of choosing the lengths of the glue periods, under a constraint on the total glue period per cycle, so as to minimize a weighted sum of the mean waiting times.\u3cbr/\u3

Cognitive Improvement in Older Adults with Mild Cognitive Impairment: Evidence from a Multi-Strategic Metamemory Training

Intervention programs to relieve memory impairment and memory-related complaints in older adults with mild cognitive impairment are needed. Objective: The purpose of the current study was to assess the efficacy of a novel cognitive training approach—named multi-strategic metamemory training—in older adults with amnestic mild cognitive impairment. Among a total of 113 older adults with mild cognitive impairment, 66 participated in the memory training program (training group) and 47 did not (control group). Repeated measures of analysis of variance revealed that compared with the control group, the training group experienced: (i) a significantly greater increase in cognitive test scores of long-term delayed free recall (Finteraction = 6.04, p = 0.016) and fluency (Finteraction = 4.11, p = 0.045) and (ii) significantly greater decrease in their subjective memory complaints for everyday memory (Finteraction = 7.35, p = 0.009). These results suggest that the training program can improve verbal memory (i.e., delayed free recall), language processing (i.e., categorical fluency) and limit complaints in everyday instrumental memory activities of mildly impaired older adults