Evaluating the effect of the incidence angle of ALOS-2 PALSAR-2 on detecting aquaculture facilities for sustainable use of coastal space and resources

Background

Driven by the growing world population, aquaculture plays a key role in meeting the increasing demand for food. However, aquaculture facilities in Japan are widely installed in coastal waters where natural disasters, such as typhoons and tsunamis, might wash these facilities away, thereby interfering with maritime navigation safety. Therefore, it is imperative to efficiently monitor the state of aquaculture facilities daily, particularly after a disaster in real time. To this end, several new space-borne L-band synthetic aperture radars (SARs) continue to be launched now and in the future, whose utilizations are expected to increase nationally and internationally. An example is the Japan Aerospace Exploration Agency, currently operating a SAR that can be operated day and night, and even under cloudy conditions, called ALOS-2 PALSAR-2.

Methods

Based on the above facts, this study evaluated the effect of the incidence angle of ALOS-2 PALSAR-2 HH single-polarization data, using 3 m spatial resolution, on aquaculture raft detection. As the study site, we selected Ago Bay, located on the Pacific coast of Mie Prefecture in central Japan since the Nankai Trough Megathrust Earthquake and tsunamis have been predicted to occur in the future around this area. Then, we analyzed the sigma zero (backscattering coefficient) of aquaculture rafts and their surrounding sea surfaces, including the relationships between satellite orbits and aquaculture raft directions.

Results

Investigations revealed that the optimum incidence angle for detecting aquaculture rafts in this study was 33.8°-45.1°. Differences in the sigma zero values existed between the ascending and descending orbits. However, the incidence angles differed on the orbits. Then, differences in the median sigma zero values across a range of incidence angles were evaluated under the descending orbit. In addition, when the directions of the aquaculture rafts were closely perpendicular to the satellite orbit, aquaculture rafts tended to show the highest values of sigma zero due to Bragg resonance scattering. Hence, this knowledge may allow for the rapid detection of aquaculture rafts during an emergency without going on-site.

Monitoring oyster culture rafts and seagrass meadows in Nagatsura-ura Lagoon, Sanriku Coast, Japan before and after the 2011 tsunami by remote sensing: their recoveries implying the sustainable development of coastal waters

Background

Coastal ecosystems are blue infrastructures that support coastal resources and also aquaculture. Seagrass meadows, one of coastal ecosystems, provide substrates for epiphytic diatoms, which are food resources for cultured filter feeder organisms. Highly intensive coastal aquaculture degrades coastal environments to decrease seagrass meadows. Therefore, efficient aquaculture management and conservation of seagrass meadows are necessary for the sustainable development of coastal waters. In ria-type bays, non-feeding aquaculture of filter feeders such as oysters, scallops, and ascidians are actively practiced along the Sanriku Coast, Japan. Before the 2011 Great East Japan Earthquake, the over-deployment of oyster culture facilities polluted the bottom environment and formed an hypoxic bottom water layer due to the organic excrements from cultured oysters. The tsunami in 2011 devastated the aquaculture facilities and seagrass meadows along the Sanriku Coast. We mapped the oyster culture rafts and seagrass meadows in Nagatsura-ura Lagoon, Sanriku Coast before and after the tsunami and monitored those and environments after the tsunami by field surveys.

Methods

We conducted field surveys and monitored the environmental parameters in Nagatsura-ura Lagoon every month since 2014. We used high-resolution satellite remote sensing images to map oyster culture rafts and seagrass meadows at irregular time intervals from 2006 to 2019 in order to assess their distribution. In 2019, we also used an unmanned aerial vehicle to analyze the spatial variability of the position and the number of ropes suspending oyster clumps beneath the rafts.

Results

In 2013, the number and distribution of the oyster culture rafts had been completely restored to the pre-tsunami conditions. The mean area of culture raft increased after the tsunami, and ropes suspending oyster clumps attached to a raft in wider space. Experienced local fishermen also developed a method to attach less ropes to a raft, which was applied to half of the oyster culture rafts to improve oyster growth. The area of seagrass meadows has been expanding since 2013. Although the lagoon had experienced frequent oyster mass mortality events in summer before the tsunami, these events have not occurred since 2011. The 2011 earthquake and tsunami deepened the sill depth and widened the entrance to enhance water exchange and improve water quality in the lagoon. These changes brought the expansion of seagrass meadows and reduction of mass mortality events to allow sustainable oyster culture in the lagoon. Mapping and monitoring of seagrass meadows and aquaculture facilities via satellite remote sensing can provide clear visualization of their temporal changes. This can in turn facilitate effective aquaculture management and conservation of coastal ecosystems, which are crucial for the sustainable development of coastal waters.

Certified Reference Material for Analytical Quality Assurance of Minor and Trace Elements in Food and Related Matrixes Based on a Typical Japanese Diet: Interlaboratory Study

A Certified Reference Material (CRM) was prepared at the National Institute for Environmental Studies (NIES), Japan, in collaboration with the National Institute of Radiological Sciences (NIRS), Japan, for the analytical quality assurance of minor and trace elements in food and related matrixes. The starting material for the CRM was all food served in 29 households in Japan over two 3-day periods in 1997–1998, and thus the CRM represented a typical Japanese diet. All foods (meals, snacks, and beverages) were homogenized, freeze-dried, pulverized, blended, dispensed into 1100 bottles, and sterilized. The within- and between-bottle homogeneity of the prepared CRM was satisfactory for most of the elements. The concentrations of 14 elements (Na, Mg, K, Ca, Mn, Cu, Zn, As, Se, Sr, Cd, Sn, Ba, and U) were certified based on a collaborative analysis involving NIES, NIRS, and 20 other laboratories. Reference values were given for the concentrations of 12 additional elements (P, Cl, Fe, Co, Ni, Br, Rb, Mo, I, Cs, Pb, and Th). The elements certified and those given reference values include minerals, essential trace elements, contaminant elements, and long-lived radionuclides. Thus, this CRM is of practical value in the quality assurance of element analysis of foods and diets in nutritional, environmental, and radiological research.

52 THE EFFECTS OF DONOR CELL CYCLE AND THE TIMING OF OOCYTE ACTIVATION ON DEVELOPMENT OF BOVINE NUCLEAR TRANSFERRED EMBRYOS IN VIVO

The cell cycle of donor cells and recipient cytoplasts are important factors affecting development of nuclear transferred (NT) embryos. We previously showed that bovine NT embryos using pre-activated cytoplasts and early G1 cells had a high in vitro developmental rate (SSR, 2008, 41st Annual Meeting). The objective of the present study was to evaluate the effects of donor cell cycle (early G1 or G0 phase) and the timing of oocyte activation on fetal development of bovine NT embryos. Adult fibroblasts from ear skin tissue of Japanese black cattle were used as donor cells. The G0 phase cells were synchronized by serum-starvation, and the G1 phase cells were prepared from actively dividing M phase cells. NT embryo production was performed by 2 kinds of protocols as follows: 1) recipient oocytes were activated by Ca ionophore (CaI), followed with cycloheximide (CH) for 2 h, and fused with synchronized donor cells followed with cytochalasin D (CD) and CH for 1 h, then CH for 4 h (pre-activated), 2) unactivated oocytes were fused with synchronized donor cells and activation was performed by CaI 1 h after fusion, followed by with CD and CH 1 h, then CH for 4 h (post-activated). After activation treatments, NT embryos were cultured in IVD101 medium for 7 days. Then, blastocysts were transferred to recipient cows. Diagnosis of pregnancy was made by ultrasonography at days 30, 60, and 90 (Day 0 = the day of embryo transfer). As shown in Table 1, the blastocyst formation rate of the NT embryos derived from early G1 cells in the pre-activated group was higher than that from G0 cells in the post-activated group (36% v. 23%, P < 0.05). After embryo transfer, 29, 67, and 50% of recipient cows were pregnant at Day 30 in G0 post-, G1 post-, and G1 pre-activated groups, respectively. However, only 1 embryo (14%) of G0 post-activated group developed to term. In conclusion, bovine NT embryos using early G1 cells and pre-activated cytoplasts showed a high blastocyst formation rate, but the full-term development of bovine NT embryos could not be improved by using early G1 cells and pre-activated cytoplasts. Table 1.Effect of the timing of oocyte activation on developmental ability of bovine NT embryos derived from early G1 or G0 phase cells

Salsolinol is present in the bovine posterior pituitary gland and stimulates the release of prolactin both in vivo and in vitro in ruminants

The aims of the present study were to determine whether salsolinol (SAL), a dopamine-related compound, is present in the bovine posterior pituitary (PP) gland, and to clarify the effect of SAL on the secretion of prolactin (PRL) in ruminants. SAL was detected in extract of bovine PP gland using high-pressure liquid chromatography with electrochemical detection (HPLC-EC). A single intravenous (i.v.) injection of SAL (5 and 10mg/kg body weight) significantly and dose-dependently stimulated the release of PRL in goats (P<0.05). Plasma PRL levels reached a peak 10min after the injection, then gradually returned to basal values in 60-80min. The PRL-releasing pattern was similar to that in response to sulpiride (a dopamine receptor antagonist). The intracerebroventricular (i.c.v.) injection of 1mg of SAL had no significant effect on the release of PRL in calves, however, 5mg significantly stimulated the release (P<0.05) with peak values reached 30-40min after the injection. Moreover, SAL significantly stimulated the release of PRL from cultured bovine anterior pituitary cells at doses of 10(-6) and 10(-5)M, compared to control cells (P<0.05). Taken together, our data clearly show that SAL is present in extract of the PP gland of ruminants, and has PRL-releasing activity both in vivo and in vitro. Therefore, this endogenous compound is a strong candidate for the factor having PRL-releasing activity that has been previously detected in extract of the bovine PP gland.

Prompt gamma-ray analysis using cold and thermal guided neutron beams at JAERI

A highly sensitive neutron-induced prompt gamma-ray analysis (PGA) system, usable at both cold and thermal neutron beam guides of JRR-3M, has been constructed. The system was designed to achieve the lowest gamma-ray background by using lithium fluoride tiles as neutron shielding, by placing the samples in a He atmosphere and by using a Ge-bismuth germanate detector system for Compton suppression. The gamma-ray spectrometer can acquire three modes of spectra simultaneously: single, Compton suppression, and pair modes. Because of the low-energy guided neutron beams and the low-background system, analytical sensitivities and detection limits better than those in usual PGA systems have been achieved. Boron and multielemental determination by a comparative standardization have been investigated, and accuracy, precision, and detection limits for the elements in various materials were evaluated. The system has been applied to the determination of B and multielements in samples of various fields such as medical, environmental, and geological sciences.

Prediagnostic serum selenium and zinc levels and subsequent risk of lung and stomach cancer in Japan

Serum samples were collected in Hiroshima and Nagasaki, Japan, from 1970 to 1972 for 208 persons who in 1973-1983 developed stomach cancer; for 77 who in 1973-1983 developed lung cancer; and for controls matched for age, sex, city, and season of blood collection. Average serum levels of selenium and zinc were slightly (< 5%) but not significantly lower among the cancer cases than among controls. Smoking-adjusted risks of lung cancer were elevated only among those in the lowest quartiles of serum selenium [odds ratio (OR) = 1.8] and zinc (OR = 1.3); the trends in risk of this cancer with decreasing serum levels were neither linear nor significant. Little or no excess risk of stomach cancer was observed among those with lowest levels of selenium (OR = 1.0) or zinc (OR = 1.2). These exploratory findings add to limited data available from other reports showing slightly increased risks of lung cancer associated with low blood levels of selenium, but suggest little association with either lung or stomach cancer across normal selenium or zinc ranges in this Japanese population.