Seasonal patterns and bloom dynamics of phytoplankton based on satellite-derived chlorophyll-a in the eastern yellow sea.

Satellite-derived chlorophyll-a concentration (Chl-a) is essential for assessing environmental conditions, yet its application in the optically complex waters of the eastern Yellow Sea (EYS) is challenged. This study refines the Chl-a algorithm for the EYS employing a switching approach based on normalized water-leaving radiance at 555 nm wavelength according to turbidity conditions to investigate phytoplankton bloom patterns in the EYS. The refined Chl-a algorithm (EYS algorithm) outperforms prior algorithms, exhibiting a strong alignment with in situ Chl-a. Employing the EYS algorithm, seasonal and bloom patterns of Chl-a are detailed for the offshore and nearshore EYS areas. Distinct seasonal Chl-a patterns and factors influencing bloom initiation differed between the areas, and the peak Chl-a during the bloom period from 2018 to 2020 was significantly lower than the average year in both areas. Specifically, bimodal and unimodal peak patterns in Chl-a were observed in the offshore and nearshore areas, respectively. By investigating the relationships between environmental factors and bloom parameters, we identified that major controlling factors governing bloom initiation were mixed layer depth (MLD) and suspended particulate matter (SPM) in the offshore and nearshore areas, respectively. Additionally, this study proposed that the recent decrease in the peak Chl-a might be caused by rapid environmental changes such as the warming trend of sea surface temperature (SST) and the limitation of nutrients. For example, external forcing, phytoplankton growth, and nutrient dynamics can change due to increased SST and limitation of nutrients, which can lead to a decrease in Chl-a. This study contributes to understanding phytoplankton dynamics in the EYS, highlighting the importance of region-specific considerations in comprehending Chl-a patterns and bloom dynamics.

Spatio-temporal variations in organic carbon composition driven by two different major phytoplankton communities in the Ross Sea, Antarctica.

The compositions of organic carbon could be important in determining biological carbon pump efficiency. However, little information on them in relation to each algal assemblage is currently available in the Ross Sea. Here, we investigated the seasonal variations in organic carbon composition and the relative abundance of each organic carbon, including particulate organic carbon (POC), dissolved organic carbon (DOC), and transparent exopolymer particles (TEPs), characterized by different algal groups in the Ross Sea. The average POC and DOC contributions to the total organic carbon (TOC = POC + DOC) were 13.8 ± 3.7 % and 86.2 ± 3.7 % in mid-January 2019 and 20.9 ± 4.1 % and 79.1 ± 4.1 % in February-March 2018, respectively. The carbon content of TEP (TEP-C) contributed 19.6 ± 11.7 % and 4.6 ± 7.0 % of POC and TOC in mid-January and 36.2 ± 14.8 % and 9.0 ± 6.7 % in February-March, respectively. We found that the organic carbon compositions were affected by seasonal variations in the phytoplankton bloom phase, physical characteristics, and phytoplankton community structure. DOC concentrations and contributions to the TOC increased as phytoplankton cells became senescent in mid-January and decreased in February-March when phytoplankton were relatively active. From February-March, the deepened mixed layer depth encouraged TEP formation, subsequently increasing the TEP contributions. Regardless of the sampling season, all organic carbon concentrations per unit Chl-a were significantly higher in P. antarctica-abundant groups. The DOC contributions to the TOC were correspondingly higher at the P. antarctica-abundant stations in mid-January, which indicates that P. antarctica could be also important in the DOC contributions in the Ross Sea. The rapid alteration in environmental characteristics and phytoplankton community structures in the Ross Sea due to climate change could affect the organic carbon pool at the euphotic layer which consequently could determine the efficiency of the biological pump.

Sovesudil (locally acting rho kinase inhibitor) for the treatment of normal-tension glaucoma: the randomized phase II study.

PURPOSE: To evaluate ocular hypotensive efficacy and the safety of sovesudil (formally known as PHP-201), a novel Rho-associated protein kinase (ROCK) inhibitor, in patients with normal-tension glaucoma (NTG). DESIGN: Multicentre, prospective, double-masked, randomized, placebo-controlled, parallel clinical study. METHODS: Patients with NTG (unmedicated baseline IOP ≤ 21 mmHg) were randomized in 3 groups and treated with sovesudil in concentrations of 0.25% and 0.5%, or with a placebo three times daily (TID) for 4 weeks. The primary end-point was the mean diurnal IOP change from the baseline at week 4. Safety was recorded over a 4-week treatment period and the following 2-week observation period. RESULTS: A total of 119 patients were included in the primary efficacy analysis. The mean diurnal IOP change from the baseline at week 4 was -1.56 mmHg for the high-dose group, -1.10 mmHg for the low-dose group and -0.65 mmHg for the placebo group. The difference between the high-dose and the placebo groups was -0.91 mmHg (95% confidence intervals: -1.73, -0.09). 0.5% sovesudil TID met the criteria for superiority to the placebo. The most frequent ocular adverse event among sovesudil-treated patients was conjunctival hyperaemia (24.4% for the high-dose and 17.5% for the low-dose group) and predominately classified as mild. CONCLUSIONS: Sovesudil 0.25% and 0.5% TID showed statistically significant IOP-lowering effects and 0.5% concentration's IOP-lowering effects met the superiority criteria in comparison with the placebo at week 4. Sovesudil was well tolerated with mild adverse events including relatively low incidence of conjunctival hyperaemia in patients with NTG.

Hand-held aperture-sharing camera for a multiview image set.

A hand-held camera that is capable of acquiring full parallax multiview images is introduced. Since the camera is based on spatial sharing of the aperture stop of a digital camera, it is easy to manufacture. The aperture stop is spatially shared by a 2D high-speed liquid crystal (LC) shutter array that is fixed on the front surface of the camera objective. The shutter array consists of 8×8 LC shutters to acquire 8×8 multiview images. The equivalent optical configuration of the camera is not different from that of a parallel-type multiview camera array. Each of the multiview images has an equal disparity from its neighbors and has the full detector resolution of the camera. The disparity is small enough to be used in light field imaging. The depth resolution and the resolvable number of depth layers calculated from the configuration are not different from those obtained experimentally.

Viewing zones in three-dimensional imaging systems based on lenticular, parallax-barrier, and microlens-array plates.

The viewing zone of autostereoscopic imaging systems that use lenticular, parallax-barrier, and microlens-array plates as the viewing-zone-forming optics is analyzed in order to verify the image-quality differences between different locations of the zone. The viewing zone consists of many subzones. The images seen at most of these subzones are composed of at least one image strip selected from the total number of different view images displayed. These different view images are not mixed but patched to form a complete image. This image patching deteriorates the quality of the image seen at different subzones. We attempt to quantify the quality of the image seen at these viewing subzones by taking the inverse of the number of different view images patched together at different subzones. Although the combined viewing zone can be extended to almost all of the front space of the imaging system, in reality it is limited mainly by the image quality.