Factors affecting the biodegradability of biodegradable polyester in soil

The biodegradabilities of two polyester, P(3HB-co-3HV) and PCL, in soil were studied to examine the factors affecting the biodegradability of biodegradable plastics in soil. The polymers were mixed with soil and the time course of the biodegradation of the polymer was measured by analyzing the residual polymer. The polymer biodegraded little in early period of the test, but did in the first-order kinetics after a certain time which was dependent on the test substance and soil used. The rate constant and the induction period of the biodegradation were determined from the residual curve. The rate constant and the induction period for P(3HB-co-3HV) increased and reached to the constant values with increasing the particle size of the test substance. Both values depended on the kind of test soil and on the sampling date for the same kind of soil. The variation in the biodegradability among the same kind of soil was primarily attributed to the variation in water content of the soil. The rate constant and the induction period of PCL were smaller and longer than P(3HB-co-3HV), respectively.     

Spatial distribution and source identification of wet deposition at remote EANET sites in Japan

Wet deposition of major ions was discussed from the viewpoint of its potential sources for six remote EANET sites in Japan (Rishiri, Happo, Oki, Ogasawara, Yusuhara, and Hedo) having sufficiently high data completeness during 2000–2004. The annual deposition for each site ranged from 12.1 to 46.6 meq m⁻² yr⁻¹ for nss-SO₄²⁻, from 5.0 to 21.9 meq m⁻² yr⁻¹ for NO₃⁻. The ranges of annual deposition of the two ions for the sites were lower than those for urban and rural sites in Japanese Acid Deposition Survey by Ministry of the Environment, Japan, and higher than those for global remote marine sites. Factor analysis was performed on log-transformed daily wet deposition of major ions for each site. The obtained two factors were interpreted as (1) acid and soil source (or acid source for some sites), and (2) sea-salt source for all the sites. This indicates that wet deposition of ions over the remote areas in Japan has a similar structure in terms of types of sources. Factor scores of acid and soil source were relatively high during Kosa (Asian dust) events in spring in western Japan. Back-trajectories for high-deposition episodes of acid and soil source (or acid source) for the remote sites showed that episodic air masses frequently came from the northeastern area of Asian Continent in spring and winter, and from central China in summer and autumn. This indicates a large contribution of continental emissions to wet deposition of ions over the remote areas in Japan.     

Tibial hemimelia syndrome: Prenatal diagnosis by real-time ultrasound

The tibial hemimelia syndrome is a rare autosomal dominant condition associated with limb deficiencies. We recently diagnosed this condition in a pregnancy at 16·5 weeks' gestation by ultrasound and a positive family history. To our knowledge, this represents the first case to be detected prenatally.     

How should surface elevation table data be analyzed? A comparison of several commonly used analysis methods and one newly proposed approach

Environmental and Ecological Statistics - The use of surface elevation table (SET) instruments to monitor elevation changes at low elevation coastal locations has steadily increased in recent...     

Peer influence predicts speeding prevalence among teenage drivers

Impact on IndustryPreventing speed-related crashes could reduce costs and improve efficiency in the transportation industry.ObjectiveThis research examined the psychosocial and personality predictors of observed speeding among young drivers.MethodSurvey and driving data were collected from 42 newly-licensed teenage drivers during the first 18 months of licensure. Speeding (i.e., driving 10 mph over the speed limit; about 16 km/h) was assessed by comparing speed data collected with recording systems installed in participants' vehicles with posted speed limits.ResultsSpeeding was correlated with elevated g-force event rates (r = 0.335, pb0.05), increased over time, and predicted by day vs. night trips, higher sensation seeking, substance use, tolerance of deviance, susceptibility to peer pressure, and number of risky friends. Perceived risk was a significant mediator of the association between speeding and risky friends.ConclusionThe findings support the contention that social norms may influence teenage speeding behavior and this relationship may operate through perceived risk.