A Time-Space Analysis of Urban Activities with Focus on the Relationship between ICT and Activity-Travel

Information and communications technology (ICT) has evolved substantially and impacted urban residents’ everyday life quite substantially in the past decade. The rapid spread of mobile telecommunications technologies has produced significant changes in relationships among communications, marketing and distribution, and transportation. As mobile technologies diminish time-space constraints that have governed telecommunication, they are prompting the emergence of new life styles with unprecedented ways in which urban space is consumed. The focus of this study is on how mobile telecommunication technologies have influenced daily activity and travel behaviors of urban residents. Temporal and spatial characteristics of their activity-travel patterns are empirically analyzed using activity diary data sets collected by the authors in the Kofu area of Japan. The survey is designed with the intent of capturing both patterns of movements in the urban area and patterns of activities that induced the movements. Questions regarding telecommunications activities are introduced into the activity-travel diary that had been developed by the authors to facilitate the acquisition of information on the occurrence and contents of telecommunications activities. The analytical framework of this study is formed by integrating urban residents’ time-space paths and virtual links representing telecommunications activities. Time-space paths are formed in a physical urban space while satisfying temporal and spatial constraints imposed by Hägerstrand’s prism. Conventional means of inter-individual communication (meeting, stationary telephones, mailed letters and telegrams) are all subject to certain constraints in the time-space domain. On the other hand, telecommunications activities by mobile technologies are not subjected to many of the constraints and can influence travel decisions more spontaneously than do conventional means of communication. Several hypotheses concerning ICT and activity patterns are postulated and empirically examined with the results of the diary surveys. Examples of the hypotheses are as follows. As the use of mobile telecommunications technologies increases, 1) the activity frequency tends to increase, 2) the spatial distribution of activities tends to spread out, that is, the action space tends to expand spatially, and 3) patterns of trip chaining tend to change themselves, with more stops incorporated into a home-based trip chain (i.e., a sequence of trips starting from and ending at home, through which a set of activity locations are visited). It is also hypothesized that 4) the way mobile technologies influence the individual’s activity-travel patterns varies by his personal characteristics, especially life cycle stage and life style. The Survey of Communication, Activity and Travel, denoted by “SCAT,” was conducted twice to form the database of this study. The first survey involved about 150 university students and data on weekly activity patterns and mobile telecommunication incidents were collected. The second survey addressed about 150 households (322 individuals) and activity diaries on two consecutive days and mobile telecommunication information were obtained. The first SCAT data are used to examine basic properties of ICT–activity-travel relationships of “heavy mobile-informed travelers” because students are certainly standing on the forefront of ICT use. On the other hand, the second SCAT data are used to analyze characteristics of joint activity engagement by household members as a result of ICT use among household members. Then, using both of the SCAT data sets, the hypotheses are examined and statistical evidence is presented. Finally, implications of the findings are summarized and directions are suggested for future research on ICT, activity and travel.

Association between body mass index and chronic kidney disease: A population-based, cross-sectional study of a Japanese community

Chronic kidney disease (CKD) has recently been recognized as a risk factor for cardiovascular disease, while the mechanism by which CKD develops remained to be clarified. In the present study, we conducted a cross-sectional, community-based study to identify the factor(s) associated with CKD. We examined 1978 local residents of the Kiyotake area of Japan (697 males and 1281 females; age, 60.8 ± 11.0 years; mean ± SD), who had an annual health check-up. Diagnosis of CKD was made based on dipstick proteinuria of +1 or higher, or on a reduced glomerular filtration rate (GFR) estimated from serum creatinine level to less than 60 ml/min/1.73 m2. Body mass index (BMI) and prevalence of obesity in the residents with CKD were found to be higher than in those without CKD in both genders. When compared with the residents without CKD, the ratios of residents taking antihypertensive medicines were higher in both genders, and the blood pressure and fasting blood glucose levels of males and the triglyceride level of females were elevated in those with CKD. These parameters or factors were found to be significant for CKD by a univariate logistic analysis. We further analyzed the data with a multivariate logistic method using age, BMI, antihypertensive and antidyslipidemic medicines, blood pressure, serum lipid and glucose as independent covariates, and found that BMI was a significant parameter independently correlated with CKD in both genders. Thus, increased BMI is associated with CKD independently of blood pressure, serum lipid and glucose levels in the general population

Modeling circadian and sleep-homeostatic effects on short-term interval timing

Short-term interval timing i.e., perception and action relating to durations in the seconds range, has been suggested to display time-of-day as well as wake dependent fluctuations due to circadian and sleep-homeostatic changes to the rate at which an underlying pacemaker emits pulses; pertinent human data being relatively sparse and lacking in consistency however, the phenomenon remains elusive and its mechanism poorly understood. To better characterize the putative circadian and sleep-homeostatic effects on interval timing and to assess the ability of a pacemaker-based mechanism to account for the data, we measured timing performance in eighteen young healthy male subjects across two epochs of sustained wakefulness of 38.67 h each, conducted prior to (under entrained conditions) and following (under free-running conditions) a 28 h sleep-wake schedule, using the methods of duration estimation and duration production on target intervals of 10 and 40 s. Our findings of opposing oscillatory time courses across both epochs of sustained wakefulness that combine with increasing and, respectively, decreasing, saturating exponential change for the tasks of estimation and production are consistent with the hypothesis that a pacemaker emitting pulses at a rate controlled by the circadian oscillator and increasing with time awake determines human short-term interval timing; the duration-specificity of this pattern is interpreted as reflecting challenges to maintaining stable attention to the task that progressively increase with stimulus magnitude and thereby moderate the effects of pacemaker-rate changes on overt behavior

セイタイ シリョウヨウ カイリョウガタ NMR プローブ ノ サクセイ ト ヒョウカ

We have constructed NMR signal detectors （probes） to measure the NMR spectra of living organs and tissues kept under physiological conditions. The probes consisted of non-magnetic aluminum alloy cylinder to support the detection coil made of cupper, mounted on a Teflon plate with acrylics plates and rods, however, the recovery time to the static magnetic field after turning off of the pulsed gradient field was more than 10 times longer than that of the micro-MRI probe available commercially. The re-design of our probes, such as acrylics cylinder to support the coil, together with readjustment of the eddy current compensation circuit, provided us the recovery time to the static field less than 1 msec, making it possible to measure the diffusion coefficient of Na+ ion using the pulsed field gradient spin echo method. The diffusion coefficient of Na+ ion in skeletal muscle isolated from bullfrog was 0.6 time larger than that in Ringer’s solution, suggesting a high viscosity in the skeletal muscle