As the sonic boom prediction method, the usefulness of the full-field simulation, in which the whole flow field including both the zone around a supersonic body and that on the ground is analyzed as a single computational domain, is assessed in this paper. The three dimensional Euler analyses including the gravity term have been numerically conducted to take into account the variation of the atmospheric properties with the altitude. The solutionadaptive structured grids are constructed by advancing the computational domain sector by sector for the grid lines to be aligned with the shock wave surfaces. The computations are made to reproduce the D-SEND#1 flight test by Japan Aerospace Exploration Agency (JAXA). The computational results are validated by comparing with the results of the waveform parameter method and the flight test data taken from the D-SEND database provided by JAXA. The maximum pressure rises of the present full-field simulations agree well with those of the waveform parameter method and the flight test data. Consequently, the present full-field simulations seem promising to analyze the natures of the sonic boom propagation in the realistic atmosphere model.
Plastics debris in the marine environment, including resin pellets, fragments and microscopic plastic fragments, contain organic contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons, petroleum hydrocarbons, organochlorine pesticides (2,2'-bis(p-chlorophenyl)-1,1,1-trichloroethane, hexachlorinated hexanes), polybrominated diphenylethers, alkylphenols and bisphenol A, at concentrations from sub ng g(-1) to microg g(-1). Some of these compounds are added during plastics manufacture, while others adsorb from the surrounding seawater. Concentrations of hydrophobic contaminants adsorbed on plastics showed distinct spatial variations reflecting global pollution patterns. Model calculations and experimental observations consistently show that polyethylene accumulates more organic contaminants than other plastics such as polypropylene and polyvinyl chloride. Both a mathematical model using equilibrium partitioning and experimental data have demonstrated the transfer of contaminants from plastic to organisms. A feeding experiment indicated that PCBs could transfer from contaminated plastics to streaked shearwater chicks. Plasticizers, other plastics additives and constitutional monomers also present potential threats in terrestrial environments because they can leach from waste disposal sites into groundwater and/or surface waters. Leaching and degradation of plasticizers and polymers are complex phenomena dependent on environmental conditions in the landfill and the chemical properties of each additive. Bisphenol A concentrations in leachates from municipal waste disposal sites in tropical Asia ranged from sub microg l(-1) to mg l(-1) and were correlated with the level of economic development.
Abstract Anthropogenic marine debris is a threat to marine organisms. Understanding how this debris spatially distributes at sea and may become associated with marine wildlife are key steps to tackle this current issue. Using bird-borne GPS- and video-loggers on 13 black-footed albatrosses Phoebastria nigripes breeding in Torishima, Japan, we examined the distribution of large floating debris in the Kuroshio Current area, western North Pacific. A total of 16 floating debris, including styrofoam (n = 4), plastic pieces (n = 3), plastic sheet (n = 1), fishery-related items (rope or netting, n = 4), and unidentified debris (n = 4), were recorded across the 9003 km covered by nine birds. The debris was concentrated in the southern area of the Kuroshio Current, where the surface current was weak, and the albatrosses were foraging. The albatrosses displayed changes in flight direction towards the debris when at a mean distance of 4.9 km, similarly to when approaching prey, and one bird was observed pecking at a plastic sheet; indicating that albatrosses actively interacted with the debris. This paper shows the usefulness of studying wide-ranging marine predators through the use of combined biologging tools, and highlights areas with increased risk of debris exposure and behavioral responses to debris items.
ABSTRACT Incomplete oxidation of glucose by Gluconobacter sp. strain CHM43 produces gluconic acid and then 2- or 5-ketogluconic acid. Although 2-keto-D-gluconate (2KG) is a valuable compound, it is sometimes consumed by Gluconobacter itself via an unknown metabolic pathway. We anticipated that 2KG reductase (2KGR) would be a key enzyme in 2KG metabolism. GLF_0478 and GLF_1777 were identified in the genome of strain CHM43, which encode proteins with 70% and 48% amino acid sequence identity, respectively, to the 2KGR of Gluconobacter oxydans strain 621H. Constructed mutant derivatives of strain CHM43 lacking GLF_0478 , GLF_1777 , or both were examined for their 2KG consumption ability. Strains ∆ GLF_0478 and ∆ GLF_1777 consumed 2KG like the parental strain. However, the double-deletion (∆∆) strain did not consume 2KG at all, although it produced 2KG like the parental strain. Strains ∆ GLF_0478 and ∆ GLF_1777 each showed decreased 2KGR activity compared with the parental strain, and strain ΔΔ lost 2KGR activity. These results suggest that reduction of 2KG catalyzed by GLF_0478 and GLF_1777 is the committed step in 2KG metabolism in Gluconobacter sp. strain CHM43. The two 2KGRs showed high activity at neutral pH and lower K M values for NADPH than NADH. Results of induction experiments suggest that GLF_0478 is constitutively expressed at a low level but induced by 2KG, and GLF_1777 is also inducible by 2KG but repressed in the absence of an inducer. Our study that characterizes the key genes for 2KG consumption in Gluconobacter gives insights for improvement of biological 2KG production systems. IMPORTANCE 2-Keto-D-gluconate (2KG), a product of incomplete oxidation of glucose by acetic acid bacteria including Gluconobacter spp., is used for various purposes, including in the food industry. Gluconobacter also consumes 2KG via an unclear metabolic pathway. It is reported that Pseudomonas spp. and Cupriavidus necator phosphorylate 2KG in the first step of 2KG metabolism, but some enteric bacteria including Escherichia coli reduce 2KG. This study evaluated the 2KG consumption ability of a mutant derivative of a strain of Gluconobacter that lacks two putative 2KGR-encoding genes. The mutant strain did not consume 2KG at all; the two 2KGRs were each found to catalyze 2KG reduction. It is concluded that reduction of 2KG is the committed step in 2KG metabolism in Gluconobacter . The results presented here give insights that might facilitate improvement of 2KG production systems that use Gluconobacter .
Ocean-scale monitoring of pollution is challenging. Seabirds are useful indicators because they travel over a broad foraging range. Nevertheless, this coarse spatial resolution is not fine enough to discriminate pollution in a finer scale. Previous studies have demonstrated that pollution levels are higher in the Sea of Japan and South and East China Seas than the Northen Pacific Ocean. To test these findings in a wide-ranging animal, we tracked streaked shearwaters (Calonectris leucomelas) from four islands in Japan using global positioning system (GPS) and measured persistent organic pollutants (POPs) in the oil of their preen glands. The POPs did not change during 6 to 21 days when birds from Awashima were foraging only in the Sea of Japan, while it increased when they crossed to the Pacific through the Tsugaru Strait and foraged along the eastern coast of Hokkaido where industrial cities occur. These results indicate that POPs in the oil reflect relatively short-term exposure. Concentrations of POPs displayed greater variation among regions. Total polychlorinated biphenyls were highest in birds foraging in a small area of the semiclosed Seto Inland Sea surrounded by urbanized coast, p,p′-dichlorodiphenyltrichloroethane (DDT) was highest in birds foraging in the East China Sea, and total hexachlorocyclohexanes were highest in birds foraging in the Sea of Japan. All were lowest in birds foraging in the Pacific. This distribution of POPs concentration partly agrees with previous findings based on mussels, fish, and seawater and possibly reflects the mobility and emission sources of each type of POP. These results highlight the importance of information on the foraging area of highly mobile top predators to make them more effective monitors of regional marine pollution.
