The development of a coupled model (PCPF-SWMS) to simulate water flow and pollutant transport in Japanese paddy fields   总被引：1，自引：0，他引：1  

Julien Tournebize  Hirozumi Watanabe  Kazuhiro Takagi  Taku Nishimura 《Paddy and Water Environment》2006,4(1):39-51

A new coupled model (PCPF–SWMS) was developed for simulating fate and behavior of pollutant in paddy water and paddy soil. The model coupled the PCPF-1, a lumped model simulating pesticide concentrations in paddy water and 1 cm-surface sediment compartment, and the SWMS-2D, a finite element numerical model solving Richard's and advection-dispersion equations for solute transport in soil compartment. The coupling involved improvements on interactions of the water flow and the concentration the pollutant of at the soil interface between both compartments. The monitoring data collected from experimental plots in Tsukuba, Japan in 1998 and 1999 were used to parameterise and calibrate hydraulic functioning, hydrodynamic and hydrodispersive parameters of the paddy soil. The analysis on the hydraulic functioning of paddy soil revealed that the hard pan layer was the key factor controlling percolation rate and tracer transport. Matric potential and tracer monitoring highlighted the evolution of saturated hydraulic conductivity (K _S) of hard pan layer during the crop season. K _S slightly decreased after puddling by clay clogging and strongly increased after mid term drainage by drying cracks. The model was able to calculate residential time in every soil layers. Residential time of tracer in top saturated layers was evaluated to be less than 40 days. It took 60 days to reach the unsaturated layers below hardpan layer.  相似文献   

The mode of operation of a regulating reservoir for effective use of river flow     

Shinichi Nishimura  Sang-bong Lee  Kengo Ito  Masateru Senge 《Paddy and Water Environment》2005,3(3):149-154

In the absence of a reservoir on the downstream side, a river flow that increases temporarily by rainfall cannot be stored and discharged apart from requirements in a command area. This unused water (excess water) occurs to some extent even in a drought year and making effective use of this supply is considered as one of the countermeasures for water shortage. Setting up a regulating reservoir on the upstream side of head works is regarded as one of the methods for making effective use of excess water. The inflow to the river and water delivery loss occurred from rainfall are stored in the regulating reservoir and supplied to the command area on the downstream side as agricultural water. An operational method for the regulating reservoir to effectively utilize the excess water was examined for a canal system by simulation. In an investigated area, there was excess water even in drought years, and making use of it through the regulating reservoir whose capacity is smaller compared to that of a dam can become one of the countermeasures for the drought period. The simulation in this study could estimate quantitatively the effect of the regulating reservoir to make the excess water effective.  相似文献   

Islet recovery and reversal of murine type 1 diabetes in the absence of any infused spleen cell contribution     

Nishio J  Gaglia JL  Turvey SE  Campbell C  Benoist C  Mathis D 《Science (New York, N.Y.)》2006,311(5768):1775-1778

A cure for type 1 diabetes will probably require the provision or elicitation of new pancreatic islet beta cells as well as the reestablishment of immunological tolerance. A 2003 study reported achievement of both advances in the NOD mouse model by coupling injection of Freund's complete adjuvant with infusion of allogeneic spleen cells. It was concluded that the adjuvant eliminated anti-islet autoimmunity and the donor splenocytes differentiated into insulin-producing (presumably beta) cells, culminating in islet regeneration. Here, we provide data indicating that the recovered islets were all of host origin, reflecting that the diabetic NOD mice actually retain substantial beta cell mass, which can be rejuvenated/regenerated to reverse disease upon adjuvant-dependent dampening of autoimmunity.  相似文献   

Possible association of glaucoma with pectinate ligament dysplasia and narrowing of the iridocorneal angle in Shiba Inu dogs in Japan     

Kato K  Sasaki N  Matsunaga S  Mochizuki M  Nishimura R  Ogawa H 《Veterinary ophthalmology》2006,9(2):71-75

The purpose of the study was to describe the shape of the pectinate ligament (PL) and to estimate the width of the iridocorneal angle (ICA) in glaucomatous and non-glaucomatous eye of Shiba Inu dogs in Japan. One hundred fourteen Shiba Inu dogs were presented to the Veterinary Medical Center at the University of Tokyo between June 1998 and June 2003. Among these, 46 dogs had glaucoma; the remaining 68 dogs were presented for routine vaccinations or heartworm testing and were used as a control population. Complete ophthalmic examination and gonioscopy were performed in all the dogs. PL and ICA were evaluated by gonioscopy and goniophotographs. Of the 46 dogs with glaucoma, 17 (37%) were affected bilaterally, and 29 (63%) were affected unilaterally. Of the 29 dogs with unilateral glaucoma, the ICA of the normotensive eye was slightly narrow in 2 eyes (7%), narrow in 12 eyes (41%), and closed in 15 eyes (52%). Among the normotensive control group, the ICA was open in 13 dogs (19%), slightly narrow in 29 (43%), narrow in 22 (32%), and closed in 4 (6%). In dogs with narrow and slightly narrow ICAs, the PLs were thickened, and in some cases, formed a solid sheet. The majority of dogs with glaucoma had changes in both ICA and PL. A narrow or slightly narrow ICA was also detected in the majority of normotensive control dogs. This study suggests that ICA narrowing and PL thickening is a common abnormality in Shiba Inu dogs in Japan and may predispose those dogs to glaucoma.  相似文献   

Promotive effect of soil solution on germination of Monochoria vaginalis under paddy conditions     

Takuhito Nozoe  Junko Tazawa  Akira Uchino  Shigenori Miura 《Soil Science and Plant Nutrition》2018,64(3):396-405

ABSTRACT

Growth of the weed Monochoria vaginalis (Burm. f.) Kunth under the conditions of organic rice production is a serious problem. The reason for the growth of M. vaginalis being dominant, especially in organic rice production, is not fully understood. In this study, laboratory experiments were conducted to analyze soil and seed factors in relation to the promotion of germination. (1) After incubation of flooded soil with or without the addition of rice bran (0.3%, 0.6%, and 0.9% in an air-dried soil basis), soil solutions were recovered and seeds of M. vaginalis were incubated in the soil solutions. Germination in the soils solutions without and with 0.3% rice bran was greater than that in distilled water. However, germination was suppressed in the presence of 0.6% and 0.9% of rice bran. These findings indicate that the solution from the soils with rice bran has different effects that may either increase or decrease germination. (2) A mixture of air-dried soil and distilled water was filtered to obtain a soil solution. Seeds were incubated in the soil solution (same as above). Environmental and physiological factors affected germination: exposure of seeds to light was an environmental factor and high germination activity and shallow dormancy of seed were physiological. The recovered soil solution promoted germination when these factors were not optimized. (3) There was a negative and significant correlation between dissolved oxygen (DO) in the soil solution and germination, indicating that a low content of DO was a promotive factor for germination. (4) Based on an experiment using pH buffers, germination increased with decrease in pH of soil solution, as long as the pH ranged from 4.0 to 7.0. This finding indicates that pH is also a factor that promotes germination.  相似文献   

Impact of Long-Term Perfluorooctanoic Acid (PFOA) Exposure on Activated Sludge Process     

Xiaolong Yu  Fumitake Nishimura  Taira Hidaka 《Water, air, and soil pollution》2018,229(4):134

Poly- and perfluorinated alkyl substances (PFASs) are groups of persistent toxic substances that have been commonly detected in wastewater treatment plants (WWTPs). In some cases, the activated sludge (AS) in WWTPs will encounter special wastewaters containing PFASs up to tens of milligram per liter (mg L^?1). However, under this condition, the potential impacts of PFASs on AS process remain unclear. In the present research, a lab-scale sequencing batch reactor was continuously exposed to perfluorooctanoic acid (PFOA), used as a representation for PFASs, at 20 mg L^?1 to mimic the extreme condition. The objective is to explore the impact of PFOA on AS process in terms of its wastewater treatment performance and evolution of microbial communities. The results indicate that PFOA restrained the microbial growth and affected the dissolved organic carbon removal. These negative impacts could be recovered after long-term adaptation. Besides, 20 mg L^?1 PFOA shows limited inhibition on nitrification and denitrification, suggesting a safe exposure level of PFOA for nitrogen removal. For microbial evolution, PFOA induced changes of communities during long-term exposure. The high abundance of Bacteroidetes, Proteobacteria, and Acidobacteria maintained over time reveals their tolerance towards PFOA. The occurrences of PFOA-resistant species are also observed. The present research provides new insight into the possible impacts of typical PFAS at high concentrations on AS process.  相似文献   

Rapid semi-quantification of triacylglycerols,phosphatidylcholines, and free fatty acids in the rice bran of one grain     

Junko Nagamoto  Ai Sawazaki  Motonori Miyago  Bungo Shirouchi  Mitsukazu Sakata  Li-tao TONG  Toshihiro Kumamaru  Masao Sato 《农业科学学报》2018,17(5):977-981

We developed a microplate assay method for determining the contents of triacylglycerols(TAGs), phosphatidylcholines(PCs), and free fatty acids(FFAs) in the rice bran of one grain using enzymatic reactions. In this method, enzymes from commercially available kits were used. Optimum reaction conditions were established. It was found that Nonidet P-40 was the optimal among the three surfactants used(Triton X-100, Tween 40, and Nonidet P-40) when lipid was dissolved in a reaction solution. Using this method, it was possible to quantify TAGs, PCs, and FFAs in concentration ranges of 7–150, 5–70, and 8–200 mg L~(–1), respectively. Furthermore, when the TAG contents in the rice bran were measured, the values closely corresponded to those obtained by extracting from large amounts of rice bran. However, sufficient data on the PC and FFA contents in rice bran are not available for valid comparisons. Although this method can accurately quantify the TAG contents in the rice bran of one grain, the accuracy of the PC and FFA contents has not been verified. Hence, future study is necessary.  相似文献   

Effect of Steel Slag to Improve Soil Quality of Tsunami-Impacted Land while Reducing the Risk of Heavy Metal Bioaccumulation     

Marco Antonio León-Romero  Paula Cecilia Soto-Ríos  Munehiro Nomura  Osamu Nishimura 《Water, air, and soil pollution》2018,229(1):12

After the tsunami caused by the Great East Japan Earthquake, marine sediment was taken from the sea bottom and deposited over local agricultural fields. The marine sediment already contained an unknown amount of heavy metals, due to anthropogenic activities prior to the tsunami, which might affect plants, animals, and humans. Furthermore, soil salinity in tsunami-inundated land greatly increased. Three different amounts of steel slag were employed as pretreatment agent in order to improve agricultural soil quality. The soil samples treated with 2% of steel slag present a remarkable increase of A. thaliana biomass production with low BCF and TF values for most of the heavy metals. It was concluded that steel slag pretreatment used in the tsunami-inundated agricultural lands produced a noteworthy improvement in soil quality which lead to a positive stimulative effect on plant growth, and the slag addition treatment proved to be a promising treatment that might be used for phytostabilization of slightly contaminated soils.  相似文献   

Biosorption of Mercury by Reed (<Emphasis Type="Italic">Phragmites australis</Emphasis>) as a Potential Clean Water Technology     

Paula Cecilia Soto-Ríos  Marco Antonio León-Romero  Otongtuya Sukhbaatar  Osamu Nishimura 《Water, air, and soil pollution》2018,229(10):328

Heavy metals are causing serious environmental and health problems worldwide, especially in places where mining is one of the major drivers of the country’s economy. Conventional technologies are considered expensive when providing the safe water; for this reason, new clean water technologies are needed. Biosorption has gained attention as a cost-effective system that uses biological materials to remove heavy metals from water; however, it can be noted that an efficient and proven biosorbent for several heavy metal has not been found. Reed (Phragmites australis) has demonstrated to be a potential biosorbent to remove several heavy metals because it is commonly found as heavy metal accumulator in wetlands. This study is focused on mercury (Hg) removal by using reed as biosorbent. Batch experiments were conducted and the microstructure of the biosorbent was analyzed by scanning electron microscope. The Langmuir isotherm and Freundlich isotherm model was applied for the data obtained. The pseudo-first-order and pseudo-second-order models were used to test adsorption kinetics data to investigate the mechanism of biosorption. A comparison with the performance of various adsorbents reported in literature was made. The results contribute to understand the use of Phragmites australis as potential biomass for biosorbent technology since it removed mercury (Hg) effectively in high concentrations. This study supports a variety of researches to achieve clean water technologies, and biosorption has proved to be a useful alternative to the conventional systems for the removal of heavy metal ions from aqueous solution.  相似文献   

Prognosis of canine patients with nasal tumors according to modified clinical stages based on computed tomography: a retrospective study   总被引：1，自引：0，他引：1  

Kondo Y  Matsunaga S  Mochizuki M  Kadosawa T  Nakagawa T  Nishimura R  Sasaki N 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(3):207-212

To evaluate the efficacy of clinical staging based on computed tomography (CT) imaging over the World Health Organization (WHO) staging system based on radiography for nasal tumors in dogs, a retrospective study was conducted. This study used 112 dogs that had nasal tumors; they had undergone radiography and CT and had been histologically confirmed as having nasal tumors. Among 112 dogs, 85 (75.9%) were diagnosed as adenocarcinoma. Then they were analyzed for survival time according to each staging system. More than 70% of the patients with adenocarcinoma were classified as having WHO stage III. The patients classified under WHO stage II tended to survive longer than those classified under WHO stage III. Dogs classified under WHO stage III were further grouped into CT stages III and IV, and CT stage III patients had a significantly longer survival time than CT stage IV patients. In addition, patients treated with a combination of surgery and radiation had a significantly longer survival time than the patients who did not receive any treatment in CT stage III. On the other hand, different treatment modalities did not show a significant difference in the survival time of CT stage IV dogs. The results suggest that WHO stage III dogs may have various levels of tumor progression, indicating that the CT staging system may be more accurate than the WHO staging system.  相似文献