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The semantic segmentation of marine images makes it easier to describe seafloor scenes and track marine organisms. However, creating human-annotated datasets for image segmentation requires significant time and effort. Therefore, this study proposes a semisupervised learning approach that combines the mean-teacher model and U-Net architecture for segmenting seafloor images obtained from the Philippines. The proposed method performs segmentation for categories, including corals, sea urchins, sea stars, and seagrass. Traditional manual labelling methods are used for coral, sea urchins, and sea stars. For the seagrass category, which is challenging to label manually, we used the K-means clustering algorithm to obtain corresponding labelled datasets based on the characteristics of such images and evaluated the feasibility. Compared with the U-Net-based supervised method, the semi-supervised method used in this study achieved good results and accuracy values, even with fewer labelled images. • Monitoring and rapid assessment for biological habitats like corals is necessary. • Segmentation for marine benthic imagery helps characterize subsea scenes. • Creating human-annotated datasets for segmentation is high-cost. • Semi-supervised learning can alleviate the lack of labelled data in marine datasets. [ABSTRACT FROM AUTHOR]

Background: Little is known about the manner in which the superior vena cava (SVC) is activated during sinus rhythm.Objective: The purpose of this study was to assess the manner of caval activation with an ultra-high-density mapping system (Rhythmia, Boston Scientific, Marlborough, MA) and its utility for SVC isolation.Methods: Forty patients with atrial fibrillation (mean age 55 ± 12 years; paroxysmal atrial fibrillation in 23[58%]) who underwent SVC mapping with Rhythmia were studied. The location of the sinus node (SN), phrenic nerve (PN), and the manner of caval activation during sinus rhythm were analyzed. The SVC was isolated by radiofrequency applications at electrical connections, shown as breakthroughs on the Rhythmia map.Results: The SN location varied widely (lateral/posterior/anterior 60%/8%/32%), while the PN was mostly located in the lateral segment (lateral/anterior 82%/18%). In 36 patients who underwent SVC isolation, the mean number of breakthroughs was 2.5 ± 0.8. The first breakthrough predominantly located in the anterior aspect (anterior/septal/posterior/lateral 78%/14%/5%/3%), and atrial activation was conducted superiorly and clockwise from the SN (referred to as spiral activation) in 32 patients (89%). The mean rotation angle from the SN to the first breakthrough was 79° ± 41°. In addition, 10 patients (25%) showed the SN within the SVC. Although radiofrequency applications were needed at the PN capture site in 11 patients (31%) the SVC was successfully isolated without any complications in all patients.Conclusion: The SN location showed great heterogeneity; however, atrial activation predominantly showed a clockwise spiral form. This is the first report to use ultra-high-resolution mapping to demonstrate the manner of spiral activation, which is useful for the safe and efficient isolation of the SVC. [ABSTRACT FROM AUTHOR]

The Philippines has one of the most diverse seagrass meadows in south-east Asia, with substantial dugong populations still existing. However, the seagrass population is declining worldwide, and 30–40% of the seagrass areas in the Philippines have been lost in the last 50 years. The quadrat method by scuba diving has been widely used to study seagrass distribution and measure dugong feeding trails. However, this method is affected by observational skills of the divers and the survey time is usually limited by air capacity in the tank and effort for high-resolution sampling. In this study, a new method of seagrass mapping and quantification of dugong trail distribution is proposed and tested. The method produces clear and high-resolution data using acoustic and optical devices with high efficiency. The field study was conducted at Mayo Bay, southeastern Philippines. Continuous optical images were taken using a water-proof digital still camera from the sea surface by a swimmer with snorkel. Using the software PhotoScan, 3D optical images were generated from the continuous photos. The resolution of the optical image is 2.96 ± 0.17 (SD) mm per pixel so that a leaf of Halophila sp. is identifiable. By counting the pixels of dugong trails, the feeding rates were calculated and the values were 13.5% in the survey area 1 and 7.1% in area 2. The quantification method, based on high-resolution optical image generated by continuous photos, can be useful for assessing the status of the seagrass meadows and the distribution of dugong trails. [ABSTRACT FROM AUTHOR]

Abstract: Background: It is sometimes difficult to differentiate the transient appearance of atrial fibrillation (AF) after pulmonary vein (PV) isolation from a true recurrence of AF. We attempted to differentiate them by analyzing the time course after the procedure. Methods and Results: 79 patients who underwent PV isolation were divided into two groups (successful: N = 60 and unsuccessful: N = 19) according to the final outcome. Antiarrhythmic drugs were used either temporarily or continuously to treat re-appearance of AF after the procedure. The transient appearance of AF in the successful group gradually faded, while true AF recurrence in the unsuccessful group consistently increased in line with the follow-up (F/U) period. The appearance of AF after 3 months predicted a subsequent failure of the procedure with a positive/negative predictive value of 87/90%, respectively. Conclusion: Since the transient appearance of AF decreased and the true recurrence of AF increased in line with the F/U period, we should therefore wait at least 3 months before judging the outcome of PV isolation. [Copyright &y& Elsevier]

Background: Although the efficacy of pulmonary vein (PV) isolation for paroxysmal atrial fibrillation (AF) has been well-established, its effect on persistent AF has not been sufficiently established to date. Methods and Results: In 68 consecutive patients (mean age, 52 ± 10 years) with paroxysmal (45) and persistent (23) AF, isolation of all four PVs was performed and the subsequent clinical outcome was evaluated. In total, 268/272 PVs (99%) were completely isolated from the left atrium by radiofrequency applications. During a mean follow-up period of 11 months, 84% of patients with paroxysmal AF and 57% of patients with persistent AF were free from symptomatic AF without any antiarrhythmic drug (AAD) therapy (p = 0.04). In the remaining recurrent AF patients, no significant difference between the paroxysmal and persistent AF was observed as long as they took AADs which had been ineffective at baseline (freedom from AF; 98% and 96%, respectively, p = NS). Repeat procedure performed in the 12 recurrent patients (paroxysmal AF 6, persistent AF 6) allowed 11 (92%) of them to become free from AF recurrence without AADs. Conclusion: Electrical isolation of PV by standard catheter technique is equally and highly effective for both paroxysmal and persistent AF patients, when all four PVs were isolated. [Copyright &y& Elsevier]