The Relationship between Rainfall Pattern and Epilithic Diatoms in Four Streams of Central-Western Korea for Three Years (2013-2015).

To study the effect of rainfall patterns on diatom communities in four major central western streams on the Korean Peninsula during the monsoon seasons of 2013 through 2015, we measured precipitation, environmental factors, and epilithic diatoms at 42 sites before (May) and after (August and September) each monsoon. The Mangyeonggang river and Sapgyocheon stream (SS) had a high percentage of low-permeability soil, and the stream had the highest proportion (49.1%) of surrounding land in urban areas. Precipitation and precipitation frequency was closely correlated with electrical conductivity and nutrients, and this was particularly evident in SS. Epilithic diatom abundance for the most abundant species as, Navicula minima, decreased in the stream in 2013 and 2014 and increased in 2015 when precipitation and precipitation frequency were low. This was not clearly distinguishable in the ecological characteristics of each watercourse's indicator species, except in SS. The dynamic community index was highest in 2015 (ca. 5.50), and the annual changes in the index were clearly shown in SS. The precipitation pattern and the dynamic community index were negatively correlated (r = -0.026~-0.385), and the precipitation within 2 weeks (r = -0.480 for SS) before the second sampling and the frequency of 10 mm of precipitation were closely correlated in the stream (r = -0.450 for SS). The distribution of epilithic diatoms in the four watercourses is therefore affected by monsoon precipitation and precipitation frequency, and the dynamic community index is determined by soil characteristics and land use.

Benthic Diatom Communities in Korean Estuaries: Species Appearances in Relation to Environmental Variables.

In the Korean Peninsula's southern estuaries, the distributive characteristics of epilithic diatoms and the important environmental factors predicting species occurrence were examined. The collection of diatoms and measurements of water quality and land-use were performed every May between 2009 and 2016, with no influence from the Asian monsoon and snow. Throughout the study, 564 diatoms were classified with first and second dominant species of Nitzschia inconspicua and N. perminuta. Based on diatom appearance and standing crops, the 512 sampling stations were divided into four groups by cluster analysis, and two regions, namely the West and East Sea. Geographically, G1, G2, G3, and G4 were located in the East Sea, Southeast Sea, West Sea, and Southwest Sea, respectively. Canonical correspondence analysis (CCA) results indicated that environmental factors, such as turbidity, electric conductivity (EC), and total phosphorus (TP), significantly influenced the distribution of epilithic diatoms. A random forest model showed that major environmental factors influencing the diatom species appearance included EC, salinity, turbidity, and total nitrogen. This study demonstrated that the spatial distribution of epilithic diatoms in the southern estuaries of the Korean Peninsula was determined by several factors, including a geographically higher tidal current-driven turbidity increase and higher industrial or anthropogenic nutrient-loading.

Impact of posterior urethral plate repair on continence following robot-assisted laparoscopic radical prostatectomy.

PURPOSE: The objective of this study is to evaluate the continence rate following reconstruction of the posterior urethral plate in robot-assisted laparoscopic radical prostatectomy (RLRP). MATERIALS AND METHODS: A retrospective analysis of 50 men with clinically localized prostate cancer who underwent RLRP was carried out. Twenty-five patients underwent RLRP using the reconstruction of the posterior aspect of the rhabdosphincter (Rocco repair). Results of 25 consecutive patients who underwent RLRP prior to the implementation of the Rocco repair were used as the control. Continence was assessed at 7, 30, 90, and 180 days following foley catheter removal using the EPIC questionnaire as well as a follow-up interview with the surgeon. RESULTS: There was no statistically significant difference between the two groups in any of the patient demographics. At 7 days, the Rocco experimental group had a continence rate of 19% vs. 38.1% in the non-Rocco control group (p = 0.306). At 30 days, the continence rate in the Rocco group was 76.2% vs. 71.4% in the non-Rocco group (p = 1). At 90 days, the values were 88% vs. 80% (p = 0.718), respectively. At 180 days, the pad-free rate was 96% in both groups. CONCLUSION: Rocco repair offers no significant advantage in the time to recovery of continence following RLRP when continence is defined as the use of zero pads per day. On the other hand, Rocco repair was associated with increased incidence of urinary retention requiring prolonged foley catheter placement.