Potential of Argo drifters for estimating biological production within the water column

Argo drifters provide information of the vertical structure in the water column and have a potential for the improvement of understanding phytoplankton primary production and biogeochemical cycles in combination with ocean color satellite data, which can obtain the horizontal distribution of phytoplankton biomass in the surface layer. Our examples show that using Argo drifters with satellite-measured horizontal distribution of phytoplankton biomass at the sea surface allow an improved understanding of the development of the spring bloom. The other possible uses of Argo drifter are discussed

VR/AR head-mounted display system based measurement and evaluation of dynamic visual acuity

This study evaluated the dynamic visual acuity of candidates by implementing a King–Devick (K-D) test chart in a virtual reality head-mounted display (VR HMD) and an augmented reality head-mounted display (AR HMD). Hard-copy KD (HCKD), VR HMD KD (VHKD), and AR HMD KD (AHKD) tests were conducted in 30 male and female candidates in the age of 10S and 20S and subjective symptom surveys were conducted. In the subjective symptom surveys, all except one of the VHKD questionnaire items showed subjective symptoms of less than 1 point. In the comparison between HCKD and VHKD, HCKD was measured more rapidly than VHKD in all tests. In the comparison between HCKD and AHKD, HCKD was measured more rapidly than AHKD in Tests 1, 2, and 3. In the comparison between VHKD and AHKD, AHKD was measured more rapidly than VHKD in Tests 1, 2, and 3. In the correlation analyses of test platforms, all platforms were correlated with each other, except for the correlation between HCKD and VHKD in Tests 1 and 2. There was no significant difference in the frequency of errors among Tests 1, 2, and 3 across test platforms. VHKD and AHKD, which require the body to be moved to read the chart, required longer measurement time than HCKD. In the measurements of each platform, AHKD was measured closer to HCKD than VHKD, which may be because the AHKD environment is closer to the actual environment than the VHKD environment. The effectiveness of VHKD and AHKD proposed in this research was evaluated experimentally. The results suggest that treatment and training could be performed concurrently through the use of clinical test and content development of VHKD and AHKD

Interactions between topsoil properties and ecophysiological responses of mangroves (Avicennia marina) along the tidal gradient in an arid region in Qatar

This study investigated the interactions between topsoil properties and ecophysiological responses of Avicennia marina along the tidal gradient in an arid region in Qatar. In February 2017, three plots were established, each at a distance of 0 m (D0), 50 m (D50), and 100 m (D100) from the inland boundary of a mangrove forest. Soil samples were collected at 0–10-cm depth in each plot to determine the chemical properties, and the density of seedlings, saplings, and trees was measured. Moreover, above- (AGB) and below-ground biomass (BGB) were calculated using an allometric equation for A. marina with the measured diameter at breast height in February 2017. As an indicator of salt stress, chlorophyll fluorescence parameters were measured in October 2017. Salinity (45.60 ppt) and exchangeable sodium percentage (ESP; 29.02%) at D100 were significantly highest. AGB was higher at D100 (41.44 Mg ha–1) than at D0 (0 Mg ha–1) and D50 (7.33 Mg ha–1), and BGB was higher at D100 (44.91 Mg ha–1) than only at D0 (0 Mg ha–1). There was no significant difference in the density of seedlings, saplings, or trees or the chlorophyll fluorescence parameters among the plots. Salt stress was not induced despite the hypersalinity at this site, since A. marina growing in an arid climate can endure strong salinity. Soil pH was highest at D0, followed by at D50 and D100. Organic matter, total nitrogen, available phosphorus, and cation exchange capacity were significantly higher at D100 than at D0 and D50. Higher concentrations of nutrients on the seaward side might result from the tidal gradient and a large input of organic matter and low soil alkalinity.Qatar University Grant (QUUG-CAS-DBES-15/16-5); the Biodiversity Conservation Fund of Kazakhstan (Q1727701); the Korean Ministry of Environment (2014001310008

Effect of soil moisture on the response of soil respiration to open-field experimental warming and precipitation manipulation

Soil respiration (RS, Soil CO2 efflux) is the second largest carbon (C) flux in global terrestrial ecosystems, and thus, plays an important role in global and regional C cycling; moreover, it acts as a feedback mechanism between C cycling and global climate change. RS is highly responsive to temperature and moisture, factors that are closely related to climate warming and changes in precipitation regimes. Here, we examined the direct and interactive effects of climate change drivers on RS of Pinus densiflora Sieb. et Zucc. seedlings in a multifactor climate change experiment involving atmospheric temperature warming (+3 °C) and precipitation manipulations (-30% and +30%). Our results indicated that atmospheric temperature warming induced significant changes in RS (p < 0.05), enhancing RS by an average of 54.6% and 59.7% in the control and elevated precipitation plots, respectively, whereas atmospheric temperature warming reduced RS by 19.4% in plots subjected to lower rates of precipitation. However, the warming effect on RS was influenced by soil moisture. On the basis of these findings, we suggest that atmospheric temperature warming significantly influenced RS, but the warming effect on RS may be weakened by warming-induced soil drying in water-limited environments

Effectiveness of a Virtual Reality Head-Mounted Display System-based Developmental Eye Movement Test

By transplanting the Developmental Eye Movement (DEM) test chart to a virtual reality head-mounted display (VR HMD) system, this study sought to evaluate the effectiveness of the DEM test for measuring dynamic visual acuity.Thirty-nine adults aged 20–39 years of both genders were the subjects of the study. After undergoing measurement of their visual function, through medical questionnaire, interpupillary distance, near point of convergence (NPC), near point of accommodation (NPA), and far and near phoria, the correlation between the tests was analyzed performing DEM vertical, horizontal test and VR HMD DEM (VHD) vertical, horizontal test.NPC and NPA decreased significantly after the VHD test, while phoria did not. The horizontal was quicker than the vertical in the DEM test, and vice versa in the VHD test. DEM was quicker than VHD in both the vertical and horizontal directions. There was no notable difference in error frequency between DEM and VHD. In terms of DEM and VHD test, there was no notable difference in the short-range IPD and subjective symptoms of the top 10 and bottom 10 subjects. There was also no notable difference between the exercise and non-exercise groups and the game and non-game groups.The performance time for VHD, in which the chart must be read while moving the body, was longer than that of DEM. Therefore, based on the consistency of the results of both tests and the lack of a difference in error frequency and subjective symptoms, the VHD equipment proposed in this thesis is as effective as dynamic visual acuity measurement equipment. In addition, the lack of a difference between the exercise and non-exercise groups and the game and non-game groups demonstrated that the amount of exercise and game by an ordinary person does not influence their dynamic visual function