No abstract

A knowledge of fern phenology promotes understanding of the biology and ecology of ferns. In this study, the phenology of 16 fern species in a subtropical broadleaf forest (N24 degrees 46', E121 degrees 34') in northeastern Taiwan was monitored from August 1997 to August 2001. Every fern produced both fertile and sterile leaves in each year of the study. Most fertile leaves emerged in February and March, whereas most sterile leaves emerged from May to September. Most leaves reached full expansion during April-July and died during April-August. The average life span of leaves ranged from 4.4 months to 30.3 months. In seven species, fertile leaves lived longer than sterile leaves, but this difference was significant only in Pteris wallichiana. In the other nine species, sterile leaves lived longer than fertile leaves, but the difference was significant only in Cyathea spinulosa, Plagiogyria dunnii, and Plagiogyria adanata. The ephemeral fertile leaves of the two dimorphic species died soon after releasing their spores, at only 5 months of age. However, their sterile leaves survived for over 22 months. The fertile leaves of the other 14 species remained green for almost 2 years after releasing their spores. Sterile leaves remained sterile throughout their lives. Spores matured in May-July and were released in June-August. After spore release, the sporangia detached. No leaf produced a second cohort of sori. Several phenological events, including sterile leaf emergence, leaf expansion and senescence, and spore maturation and release, were significantly positively correlated with temperature but not with precipitation, whereas the emergence of fertile leaves was weakly negatively correlated with temperature and precipitation. However, those correlations varied among different species.

No abstract

This article analyses the volatility forecasting performance of the GARCH models based on various distributional assumptions in the context of stock market indices and exchange rate returns. Using rollover methods to construct the out-of-the-sample volatility forecasts, this study shows that the GARCH model combined with the logistic distribution, the scaled student's t distribution and the Riskmetrics model are preferable both in stock markets and foreign exchange markets. The exponential power and the mixture of two normal distributions are, however, less recommended. Furthermore, a complex distribution does not always outperform a simpler one, although the exact ranking depends on the application of underlying assets and the performance statistics being used.

Patients undergoing gynecological surgery commonly receive indwelling transurethral Foley catheters, however duration of catheterization is associated with risk of urinary tract infections and other adverse effects. Early removal of catheters is encouraged, however optimal timing postsurgery remains unclear. This quasi-experimental study compared outcomes for women after removal of a Foley catheter at two different times following benign gynecological surgery. Participants received either early catheter removal, within 6 hours of surgery ( n = 38) or standard catheter removal, within 12 to 24 hours of surgery ( n = 45). There were no significant differences in outcomes for discomfort scores or re-catheterization rates between groups. However, the early removal group had a significantly shorter time to first ambulation and shorter hospital stays. Early removal of Foley catheters in patients who underwent gynecological surgery did not increase adverse events. Early removal of catheters after gynecological surgery may decrease re-catheterization rates and increase patient satisfaction.

No abstract

No abstract

No abstract