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101.
Tomoyoshi?HirotaEmail author Kazuei?Usuki Masaki?Hayashi Manabu?Nemoto Yukiyoshi?Iwata Yosuke?Yanai Tomotsugu?Yazaki Satoshi?Inoue 《Mitigation and Adaptation Strategies for Global Change》2011,16(7):791-802
In the northernmost region of Japan (Hokkaido Island), earlier onsets of thick snowcover in recent years (post 1980) have
reduced the penetration depth of soil frost, resulting in over-winter survival of unharvested small potato (Solanum tuberosum) tubers that emerge as weeds in the spring in rotation crop fields. To prevent the occurrence of potato weeds, a method was
developed to manipulate soil-frost depths by artificially controlling snowcover thickness, guided by a simple numerical model
that simulates soil freezing-thawing processes using daily mean air temperature and snowcover thinckness as input variables.
The method involves removal of snowcover to expose the soil surface in the beginning of winter until the soil freezes to a
sufficient depth. After that time, snow is deposited back or allowed to accumulate naturally to prevent further penetration
of frost, which may cause undesirable delay in the seeding of spring crops. Field trials indicated that the model predicted
frost depths within several centimeters of observed values, when measured temperature and snowcover thickness were used as
model input. Based on the field and laboratory data, a soil temperature of −3°C is necessary for complete elimination of potato
tubers. To achieve this temperature in potato-burial zones without causing excessive freezing, an optimal frost depth is 0.3
to 0.4 m. The method is being adopted by progressive potato producers in the region, who use tractor-mounted snow ploughs
to manipulate snowcover over a large scale. This is an emerging new technology for agricultural adaptation to climate variability. 相似文献
102.
With the exception of several species, bumblebees are monandrous. We examined mating frequency in feral colonies of the introduced bumblebee Bombus terrestris in Japan. Using microsatellite markers, genotyping of sperm DNA stored in the spermatheca of nine queens detected multiple insemination paternities in one queen; the others were singly mated. The average effective paternity frequency estimated from the genotypes of queens and workers was 1.23; that estimated from the workers’ genotype alone was 2.12. These values were greater than those of laboratory-reared colonies in the native ranges of B. terrestris. The genotypes of one or two workers did not match those of their queens or showed paternities different from those of their nestmates; this may have arisen from either queen takeover or drifting of workers. These alien workers were responsible for the heterogeneous genotype distribution within each B. terrestris colony, resulting in higher estimates of paternity frequency than of insemination frequency. The high mating frequency of introduced B. terrestris may have occurred by artificial selection through mass breeding for commercialization. Moreover, polyandrous queens may be selectively advantageous, because reproduction by such queens is less likely to be disturbed by interspecific mating than that by monandrous queens. 相似文献
103.
Kameoka Hiroshi Ito Koji Ono Junko Banno Arisa Matsumura Chisato Haga Yuki Endo Kazuto Mizutani Satoshi Yabuki Yoshinori 《Journal of Material Cycles and Waste Management》2022,24(1):287-296
Journal of Material Cycles and Waste Management - Per- and polyfluoroalkyl substances (PFASs) are used in products, such as aqueous film-forming foam and fluorochemical surfactants, because of... 相似文献
104.
Shuhei Tomita Shin-Ichi Maekawa Mustafizur Rahman Fumi Saito Ryoichi Kizu Keiko Tohi 《毒物与环境化学》2013,95(1):113-124
Epidemiological studies suggest that diesel exhaust particles (DEP) contribute to an increase in allergic diseases. To assess the effects of DEP on the central immune system, mice were exposed to DEP by intraperitoneal (IP) administration. Exposure to DEP resulted in severe thymic involution accompanied by a reduction in the number of thymocytes, especially in cortical CD4+CD8+ double positive and double negative subsets. Core carbon particles associated with a mixture of chemical compounds in DEP did not appear to be responsible for the DEP-induced thymic involution because carbon graphite does not affect neither the number nor the CD4/CD8 profile of thymocytes. Extraction of DEP by ether, acidic and basic solvents showed that several independent fractions including the neutral ether fraction, which contains polycyclic aromatic hydrocarbons (PAH), induced thymic involution. Among major PAH components of DEP, benzo[b]fluoranthene (BbF), benzo[a]pyrene (BaP), and benzo[k]fluoranthene (BkF) were very potent inducers of thymic involution at an ED50 of less than 100?ng per mouse body. Nonetheless, DEP treatment of mice with targeted disruption of genes encoding the aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), or microsomal epoxide hydolase (mEH) indicated that DEP produced thymic involution even in the absence of PAH-induced AHR/ARNT signal transduction or mEH-mediated PAH catabolism. On the other hand, BaP-mediated thymic involution was completely dependent on AHR, partially dependent on ARNT in T cells, and independent of mEH. These results indicate that DEP-induced thymic involution is mediated both by PAH-AHR/ARNT-dependent and -independent mechanisms. 相似文献
105.
Shigeru Kawamata Satoshi Yoshimitsu Shigemitsu Tokunaga Satoshi Kubo Toshihiro Tanaka 《Marine Biology》2012,159(4):723-733
Although sediment deposition has detrimental effects on macroalgal settlement and recruitment, fucoid algae (mainly Sargassum duplicatum) thrive on rocky reefs always overlaid with fine sediments in sheltered sites of Kagoshima, Japan. The aim of the present
study was to assess their ability to settle and recruit onto sediment-covered substrata. A transplant experiment using boulders
with Sargassum juveniles attached showed that the 30-day survival rate was as high as 50% even for the juvenile stage (<10 mm) on boulders
completely buried with sediment. In addition, an outdoor tank experiment testing the effects of different sediment thicknesses
(0–4 mm) on already settled 4-day old S. duplicatum germlings indicated significant reductions in growth by the presence of sediment cover even at 0.5 mm but no significant
increase in mortality up to 2 mm. Furthermore, an in situ experiment in which sterilized cobbles were placed at a sediment-covered
site to allow sediment to settle over them before the embryo release showed a uniformly high recruitment of Sargassum over the cobbles. This suggests the presence of unknown mechanisms to allow the settlement of propagules on substrata thinly
but completely covered by fine sediments. 相似文献
106.
Toward knowledge structuring of sustainability science based on ontology engineering 总被引:1,自引:1,他引:0
Terukazu Kumazawa Osamu Saito Kouji Kozaki Takanori Matsui Riichiro Mizoguchi 《Sustainability Science》2009,4(1):99-116
In sustainability science (SS), it is difficult to identify what needs to be solved, and it is also not clear how to solve the problems that are identified. There has been no consensus on the underlying question of “What is structuring knowledge in SS?” This paper focuses on knowledge structuring accompanied by supporting of thinking. It addresses the key challenges associated with knowledge structuring in SS, identifies the requirements for the structuring of knowledge, proposes a reference model, and develops an ontology-based mapping tool as a solution to one layer of the reference model. First, we identify the important requirements for SS knowledge structuring. Second, we develop a reference model composed of five layers based on three of the requirements. Third, we develop an ontology-based mapping tool at Layer 2 of the reference model for meeting the two major challenges for SS, namely, identifying what problems should be addressed in SS itself and proposing solutions for those problems. The tool is designed to store and retrieve information regarding SS, to provide access to a prototype ontology for SS, and to create multiple maps of conceptual chains depending on a user’s interests and perspectives. Finally, we assess whether the developed tool successfully realizes the targeted part of the reference model for SS by examining the tool’s conformity to the reference model, as well as its usability, effectiveness, and constraints. Although several issues were identified in the prototype ontology and the mapping tool, the study concluded that the mapping tool is useful enough to facilitate the function of Layer 2. In particular, the mapping tool can support thinking about SS from the viewpoint of: (a) finding new potentials and risks of technological countermeasures studied in SS; (b) helping users to get a more comprehensive picture of problems and their potential solutions; and (c) providing an effective opportunity to come up with new ideas that might not be thought of without such a tool. 相似文献
107.
Masako Nakamura Ken Okaji Yoshimi Higa Eiji Yamakawa Satoshi Mitarai 《Marine Biology》2014,161(11):2521-2530
Boom and bust dynamics are a prominent characteristic of the crown-of-thorns starfish (Acanthaster planci) populations. Outbreaking starfish populations damage coral communities extensively and then often disappear quickly. In contrast, Onna village, on the central west coast of Okinawa Island, Japan, has been experiencing chronically high population densities of A. planci for decades. In this study, we examined spatial and temporal population dynamics of A. planci along the coast of Onna village, using removal data gathered over 24 years by a local fisheries cooperative. The results demonstrate that A. planci populations along the Onna coast often experienced high densities prior to 2003 and that recently, populations have again been increasing drastically. Size-frequency distributions suggest multiple, successive recruitment, as one of the driving factors maintaining A. planci populations in this location. Moreover, within the Onna area, the timing of outbreak peaks varied among different locations, showing a northward progression. 相似文献
108.
Adsorption isotherms of 5 priority surfactants on 7 river sediments were obtained. The surfactants were ready to adsorb in the same order as the adsorption on microbiologies. The adsorbed amounts per gram of the organic carbon in the sediments were nearly equal for most of the sediments. 相似文献
109.
110.
Aqueous phenol solutions containing TiO(2) nanoparticles were irradiated with ultraviolet (UV), gamma-ray and electron beams. Organic compounds were fully removed by each type of radiation in the presence of the particles. The absorbed energy of the ionizing radiation (gamma-ray and electron beams) needed for removal was much lower than that of UV photocatalysis. Phenol was decomposed by the ionizing radiation in the absence of the nanoparticles and the addition of TiO(2) had no significant effect on phenol decomposition rate. Instead, total organic carbon (TOC) removal using the ionizing radiation was accelerated drastically by TiO(2). It is suggested that TiO(2) particles affect the intermediate compounds produced through the decomposition of phenol. The amount of removed TOC per absorbed energy were compared in the absence and the presence of TiO(2) nanoparticles. Radiolysis with the nanoparticles showed consistently high rate and high efficiency of TOC removal. 相似文献