result 11275 件
| JaLCDOI | 10.18926/fest/11557 |
|---|---|
| Title Alternative | Mathematical analysis of virus infectious diseases by ordinary differential equations |
| FullText URL | 005_023_030.pdf |
| Author | Sasaki, Toru| Kajiwara, Tsuyoshi| |
| Abstract | Some mathematical models describing interaction of virus and cells in vivo are reviewed. Similar models using systems of ordinary differential equations can be used for the analysis of dynamics of virus and cells for different kinds of virus. Models for human immunodeficiency virus, hepatitis C virus and hepatitis B virus are treated here. Although models are similar, different approximations can reduce the systems to the explicitly solvable forms. The solutions obtained here can be used to estimate biological parameters. |
| Keywords | Virus Mathematica models HIV HCV HBV |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2000-02-29 |
| Volume | volume5 |
| Issue | issue1 |
| Start Page | 23 |
| End Page | 30 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313498 |
| JaLCDOI | 10.18926/fest/11556 |
|---|---|
| FullText URL | 003_011_024.pdf |
| Author | Watanabe, Masaji| |
| Abstract | We study a system that models a problem in which an oscillatory unit is coupled to a passive medium. We analyze the case in which an RCL circuit is coupled to an RC circuit. Some numerical results indicate when slow oscillations occur in coupled systems. |
| Keywords | coupled circuits Van der Pol's equation slow oscillations |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 1998-01-14 |
| Volume | volume3 |
| Issue | issue1 |
| Start Page | 11 |
| End Page | 24 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313697 |
| JaLCDOI | 10.18926/fest/11553 |
|---|---|
| Title Alternative | Mathematical analysis of pathogenesis of viral hepatitis. |
| FullText URL | 005_007_011.pdf |
| Author | Sasaki, Toru| Kajiwara, Tsuyoshi| |
| Abstract | Simple mathematical models are considered to explain the pathogenesis of viral hepatitis. Dynamics of populations of liver cells and two virus strains are analyzed qualitatively. This analysis suggests the possibility that the viral mutation causes the hepatitis from the state of carrier. |
| Keywords | hepatitis mathematical model mutation |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2000-02-29 |
| Volume | volume5 |
| Issue | issue1 |
| Start Page | 7 |
| End Page | 11 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313400 |
| JaLCDOI | 10.18926/fest/11535 |
|---|---|
| FullText URL | 006_067_079.pdf |
| Author | Kamboh Maqsood Ahmed| Oki, Yoko| Adachi, Tadashi| |
| Abstract | The distribution on Ca, K, Na and Cl in root and leaves was studied in salt tolerant variety (Chikugo Izumi) and salt sensitive variety (PB-81) of wheat under saline conditions. The plants grown in 5% Hoagland's nutrient solution were subjected to 100 mM NaCl salinity for one week before observation with scanning electron microscope and analysis of selected samples with X-ray microanalyzer. Root growth was not affected in salt tolerant variety but reduced significantly in salt sensitive variety. Shoot growth was reduced in both varieties but much higher in salt sensitive variety. Salinity increased accumulation of Na and Cl in all root cells including vascular cells in salt sensitive variety. Salt tolerant variety not only reduced uptake of Na and Cl under saline conditions but also restricted their accumulation in cortex maintaining vascular cells relatively free of these ions. Salt sensitive variety failed to block transport of Na and Cl from root to leaves leading to much accumulation of these ions in leaves under salinity sterss. |
| Keywords | Ion distribution salinity salt tolerance wheat varieties X-ray microanalysis |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2001-02-28 |
| Volume | volume6 |
| Issue | issue1 |
| Start Page | 67 |
| End Page | 79 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313904 |
| JaLCDOI | 10.18926/fest/11534 |
|---|---|
| FullText URL | 007_099_106.pdf |
| Author | Kamboh Maqsood Ahmed| Oki, Yoko| Adachi, Tadashi| |
| Abstract | A few wheat varieties including two Japanese wheat varieties were evaluated for their salt tolerance at seeding stage, their behavior to increasing salinity levels and role of Na exclusion capacity in salt tolerance mechanisms. The wheat varieties were grown in nutrient solution and subjected to 0 (control), 25,75 and 125 mM NaCl salinity levels for 7 days. Although the shoot growth was reduced while Na contents were increased progressively with increasing salinity in all varieties, the varieties were quite different in their response. Salt tolerant va rieties maintained less reduction in their root and shoot growth and better water relations in their shoots than salt sensitive varieties under saline conditions. The wheat varieties were quite different in their Na exclusion capacity. Poor growth in salt sensitive varieties might be due to higher accumulation of Na in their shoots resulting from low Na exclusion capacity of roots, higher Na transport to shoot and/or inferior compartmentation capability. |
| Keywords | growth and mineral composition increasing salinity Na exclusion capacity salt tolerance wheat varieties |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2002-03-22 |
| Volume | volume7 |
| Issue | issue1 |
| Start Page | 99 |
| End Page | 106 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313704 |
| JaLCDOI | 10.18926/fest/11525 |
|---|---|
| Title Alternative | A Study on Influence of Current Velocity on Phytoplankton |
| FullText URL | 007_045_053.pdf |
| Author | Li, Jinsong| Kawara, Osami| Ono, Yosiro| |
| Abstract | The main problems caused by eutrophication result from the increase of phytoplankton. Therefore, controlling the increase of phytoplankton is the most important. In this study, we discuss the influence of current velocity on the growth of phytoplankton based on the field experiments and laboratory experiments. The laboratory experiments for the influence of current velocity on the growth have been conducted using circular channels, and the field experiments were conducted using a shallow pond. The results of the experiments show current velocity inhibits the growth of phytoplankton. |
| Keywords | Eutrophication growth of phytoplankton influence of current velocity experiment |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2002-03-22 |
| Volume | volume7 |
| Issue | issue1 |
| Start Page | 45 |
| End Page | 53 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313529 |
| Author | Chikamori, Ken-ichi| |
|---|---|
| Published Date | 2007-03-23 |
| Publication Title | |
| Content Type | Thesis or Dissertation |
| JaLCDOI | 10.18926/fest/11516 |
|---|---|
| FullText URL | 006_001_010.pdf |
| Author | Tomita, Makoto| Otake, Masanori| |
| Abstract | In many epidemiological and medical studies, a number of cancer motralities in catagorical classification may be considered as having Poisson distribution with person-years at risk depending upon time. The cancer mortalities have been evaluated by additive or multiplicative models with regard to background and excess risks based on several covariances such as sex, age at the time of bombings, time at exposure, or ionizing radiation, cigarette smoking habits, duration of smoking habits, etc. An interest herein to examine an additive, synergistic,or antagonistic relationship between radiation exposures and cigarette smoking habits for cancer mortalities. The results revealed a highly significant antagonistic influence for cancer mortalities from all nonhematologic findings, lung and respiratory system with negative interaction between radiation exposures and cigarette smoking amounts. |
| Keywords | Excess relative risks cancer mortalities antagonistic effects prospective studies atomic bomb survivors |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2001-02-28 |
| Volume | volume6 |
| Issue | issue1 |
| Start Page | 1 |
| End Page | 10 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313814 |
| JaLCDOI | 10.18926/fest/11496 |
|---|---|
| FullText URL | 010_057_065.pdf |
| Author | Dewan Ashraf M.| Alam Md. Mahabubul| Nishigaki, Makoto| |
| Abstract | This paper is an attempt to develop a series of maps that precisely depict flood prone areas in Greater Dhaka, Bangladesh using remote sensing techniques. Multi-temporal RADARSAT SAR data were acquired and employed to delineate open water flood boundary during the floods of 1998 and 2000. Using a threshold algorithm, SAR data is segregated into water and non-water areas. The empirical threshold value was obtained by using visual interpretation technique, local knowledge of the study site and by deriving corresponding pixel values to land/water from each image. The result demonstrated that 53 percent of the study area was heavily inundated in 1998 flood which is the largest submerged area during a catastrophic scenario. In contrast, 35.32 percent area was flooded during the year 2000 which represents the area under water for a normal event. Using the reference data acquired from field visit, derived flood maps were further validated. Moderate accuracy is obtained for all flood maps, however, July 1998 image attained the highest overall accuracy (86%) in the dataset. The derived flood maps are expected to be useful to mitigate losses of lives and property from river water flooding in Greater Dhaka. Furthermore, this information would be worthwhile to develop an efficient flood disaster management system. |
| Keywords | SAR open water flood 1998 and 2000 floods Greater Dhaka RADARSAT |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2005-02-28 |
| Volume | volume10 |
| Issue | issue1 |
| Start Page | 57 |
| End Page | 65 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313953 |
| Author | So, Jun-ichi| |
|---|---|
| Published Date | 2007-03-23 |
| Publication Title | |
| Content Type | Thesis or Dissertation |
| Author | Ohtani, Yu| |
|---|---|
| Published Date | 2007-03-23 |
| Publication Title | |
| Content Type | Thesis or Dissertation |
| JaLCDOI | 10.18926/fest/11481 |
|---|---|
| FullText URL | 010_009_011.pdf |
| Author | Kajiwara, Tsuyoshi| Sasaki, Toru| |
| Abstract | An elementary proof of permanence for a simple mathematical model proposed by Nowak and Bangham. In many papers, permanence property is proved by theorems established by the general theory of dynamical system. In this paper, we present an elementary proof only using differential inequalities and the theory of linear differential equations with constant coefficients. |
| Keywords | Permanence dynamical system pathogen |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2005-02-28 |
| Volume | volume10 |
| Issue | issue1 |
| Start Page | 9 |
| End Page | 11 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313596 |
| JaLCDOI | 10.18926/fest/11466 |
|---|---|
| FullText URL | 009_099_110.pdf |
| Author | Dewan A.M.| Nishigaki, Makoto| Komatsu, Mitsuru| |
| Abstract | Dhaka city, the capital of Bangladesh and home for more than 10 million people, has been affected by seasonal flooding almost in every year, however, the situation aggravates depending on rainfall and surrounding river waters. The aim of this paper is to delineate the flood extent in Dhaka city using digital elevation model (DEM), an integral part of geographic information system. Catastrophic floods of the 1988 and 1998 events are taken into consideration. Hydro-meteorological assessment of these events revealed that the 1988 flood was severe due to the lack of flood protection in the city together with transboundary flow of the major rivers while the 1998 flood was become deluge due to incessant monsoonal downpour along with early peaked of the river water levels. The 1998 event has done colossal damage in the city compare to the 1988 event. Flood extent estimation showed that DEM data is very precious to model inundation in the city, however, in order to be spatially explicit flood model, high resolution DEM is necessary. Finally, flood management issues are reviewed and found that combination of structural and nonstructural measures are necessary to help reducing flood induced losses and damage in the city. |
| Keywords | Dhaka City Floods Digital Elevation Model 1998 and 1988 Floods |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2004-02-27 |
| Volume | volume9 |
| Issue | issue1 |
| Start Page | 99 |
| End Page | 110 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313678 |
| JaLCDOI | 10.18926/fest/11455 |
|---|---|
| FullText URL | 009_045_051.pdf |
| Author | Iuchi Takuma| Kajiwara, Tsuyoshi| |
| Abstract | Qualitative analysis for the model of HIV infection in vivo presented by Perelson and Nelson are developed. The local stability analysis is done for the interior equilibrium, and it is shown that, for some paramter value, the interior equilibrium can be unstable and a Hopf bifurcation can occur. It is shown that the boundary equilibrium is globally asymptotically stable. Last, it is shown that this system is permanent. |
| Keywords | HIV Mathematical model Stability Liapunov function |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2004-02-27 |
| Volume | volume9 |
| Issue | issue1 |
| Start Page | 45 |
| End Page | 51 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313809 |
| JaLCDOI | 10.18926/fest/11454 |
|---|---|
| FullText URL | 012_107_117.pdf |
| Author | Akhtar M. Shahbaz| Oki, Yoko| Adachi, Tadashi| Khan Md. H. R.| |
| Abstract | Acclimation to orthophosphate (Pi) deprivation via highly coordinated Pi-starvation induced (PSI) classical mechanisms such as copious quantities of H(+) and carboxylates (OAs) exudation, remodeling and modification of root architecture by increasing structural and functional plasticity, enhanced uptake rate and increased synthesis of Pi transporters would reduce or eliminate our current overreliance on expensive, polluting, and nonrenewable Pi-fertilizers. These complicated but elegant morphological, physiological, biochemical and molecular adjustments of Pi-starved plants provide an excellent example of how the unique flexibility of plant metabolism and energy transduction helps them to cope in a typically stressful environment. Pi-starved roots possess enhanced H(+)-ATPase and PEPCase which could result in increasing H(+) efflux and OAs exudations in the root vicinity. This would lead to the rhizosphere acidification, which thereby contribute to the solublization and assimilation of mineral Pi from environment. To visualize the dissolution of sparingly soluble Ca-phosphate and rhizospheric pH changes (in situ), genetically diverse Brassica cultivars were grown on agar media. Newly formed Ca-phosphate was suspended in agar containing other essential nutriens. With NH(4)(+) applied as the N source, the precipitate dissolved in the root vicinity and this was ascribed to acidification. No dissolution was occurred with No(3)(-)-nutrition. In order to observe the pH changes at the media-root interface (rhizosphere), an image analysis was carried out after embedding the roots in agar containing bromocresol purple as pH indicator. Efficient cultivar 'Brown Raya' showed greater decrease in pH than P-inefficient 'B.S.A' in the culture media. Hydroponically grown cultivars were compared with respect to P-utilization efficiency (PUE), P-stress factor (PSF), and Ca- and P-uptake at P-starvation. PUE, and Ca- and P-uptake correlated significantly (P<0.01) with biomass accumulation, indicating that higher P-uptake of efficient cultivars was because of their higher Ca-uptake, which in turn was related to their better P-acquisition and PUE. Remodelling of root architecture of efficient cultivars helped the cultivars to establish a better rooting system, which provided basis for tolerance under P-starvation. |
| Keywords | Brassica Bromocresol purple H(+) -efflux Rhizospheirc pH changes and acidification PUE |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 107 |
| End Page | 117 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313432 |
| JaLCDOI | 10.18926/fest/11453 |
|---|---|
| FullText URL | 009_037_044.pdf |
| Author | Sung Jimin| Tanaka, Yutaka| |
| Abstract | There have been proposed so far many methods of statistical diagnostics in Cox regression for checking the goodness of the estimated model or checking the adequacy of the data. The former type contains the checking of the overall goodness of fit, the validity of the assumption of proportional hazards and the proper functional forms of the effects of covariates. While the latter type contains the checking whether there exist singly and/or jointly influential observations in the data set. In the present paper we study numerically the performances of various methods of diagnostics including our method of influence analysis for multiple-case diagnostics (Sung and Tanaka, 2003) by analyzing a real data set of lung cancer patients. |
| Keywords | Cox regression Influence function Local influence Influential Subsets Cox-Snell residuals Martingale residual Deviance residual |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2004-02-27 |
| Volume | volume9 |
| Issue | issue1 |
| Start Page | 37 |
| End Page | 44 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313595 |
| JaLCDOI | 10.18926/fest/11450 |
|---|---|
| FullText URL | 012_099_106.pdf |
| Author | Akhtar M. Shahbaz| Oki, Yoko| Adachi, Tadashi| Khan Md. H. R| |
| Abstract | As a rule, ion uptake by plant cells and roots has features of saturation kinetics. This is in accordance with the assumption of control, as for example by the number of binding sites of ions (carriers, permeases), or the capacity of the proton efflux pumps, in the plasma membrane and tonoplast. Solute transport across membranes is carrier mediated transport. Protein macromolecules integrated into the membrane matrix seems to be the carriers. The carrier-mediated process is subject to kinetics assumig that the number of carriers (binding sites) in the membranes is limited. Kinetics of ion transport through a membrane is considered equivalent to relationship between an enzyme and its substrate. To obtain plants of different P status, two genetically diverse Brassica cultivars (P-tolerant 'Con-1' and P-sensitive 'Gold Rush') were grown for several weeks in nutrient solution culture media. P-uptake kinetics of the roots with intact plants in short-term experiments by monitoring P depletion in culture media revealed that P-tolerant 'Con-1' cultivar had favorable characteristics for P-uptake because of high I(max) or V(max) and low K(m) or 1/2 I(max) value than P-sensitive 'Gold Rush' cultivar. By plotting relative growth rate (RGR) and internal P-concentration (PNC) among P-tolerant (group I; Brown Raya, Con-1, Rainbow, Dunkled and Peela Raya) and P-sensitive (group II; Toria, Sultan Raya, B.S.A, Toria Selection and Gold Rush) cultivars revealed that group I cultivars showed large metabolic fraction and small structural fraction than group II cultivars which provided basis for P-stress tolerance. |
| Keywords | Brassica Membrane binding sites Carrier-mediated transport I(max) or V(max), K(m) Pi-uptake rate RGR |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 99 |
| End Page | 106 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002314027 |
| JaLCDOI | 10.18926/fest/11441 |
|---|---|
| FullText URL | 012_077_081.pdf |
| Author | Khan Md. H. R.| Mohiuddin M.| Rahman M.| Akhtar M. S.| Oki, Yoko| Adachi, Tadashi| |
| Abstract | Studies on the existing non-symbiotic diazotrophic systems still are the most promising for better use of biological nitrogen fixation (BNF) in agriculture. The possibilities for the extension of nitrogen fixation to rice plants still speculative. The prospect of extension of N(2)-fixation to other plants was originally formulated to simulate the possibilities for the biological use of atmospheric nitrogen in order to overcome the ecological and economical problems of nitrogenous fertilizers. In view of this, the present study was conducted for the characterization and identification of N(2)-fixing bacterial strains at the maturity (110 days) stage in rhizosphere of rice (BR 10, Oryza sativa L.) grown in Brahmaputra Alluvium soil of Bangladesh. The soil is characterized as 'Inceptisol' order and 'Aquept' suborder. It was identified as 'Dhamrai series', had 'silt' texture, pH 6.0 and 6.8 C/N ratio. The present results of the microbial tests on the rice rhizosphere soil demonstrated that out of 401 isolates, only 94 were branded as nitrogen fixing organisms per gram of soil, which is about 23.4% of the total isolates. Based on the selection criteria, four individual strains were selected for identification. Biochemical tests were conducted for proper identification. They were identified as Closteridium spp., Klebsiella spp., Bacillus spp. and Azospirllum spp. |
| Keywords | Azospirllum spp. Bacillus spp. BNF Closteridium spp. Diazotrophs Klebsiella spp. Oryza sativa L. |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 77 |
| End Page | 81 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313950 |
| JaLCDOI | 10.18926/fest/11436 |
|---|---|
| FullText URL | 012_063_070.pdf |
| Author | Saif Eideen S. A.| Taniguchi, Takeo| |
| Abstract | The homogenization method is used to model steel fiber reinforced concrete SFRC by converting the random distribution of fibers to a periodic one. The periodic distribution is chosen to hold similar properties of the composite material in both perpendicular directions to represent an average approximation for the random distribution. The material is modeled as a composite with brittle matrix and elastic fibers. Two patterns of the unit cell are examined to establish the homogenized stiffiness matrix in elastic and plastic stages. A rigid plastic bonding is considered between matrix and fibers. The smeared crack model is used to represent the nonlinearity of concrete. The validity of the homogenized model is examined by comparing the numerical results with the experimental results. The results show good agreement with the experimental work when a suitable pattern of the unit cell is used. |
| Keywords | fiber reinforced concrete composite materials homogenization periodicity finite element |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 63 |
| End Page | 70 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313536 |
| JaLCDOI | 10.18926/fest/11430 |
|---|---|
| FullText URL | 011_043_049.pdf |
| Author | Saif Eldeen S. A.| Taniguchi, Takeo| |
| Abstract | The simulation of mechanical bahavior of steel fiber reinforced concrete SFRC is introduced utilizing the homogenization method. The random distribution of fibers has been converted to a periodic distribution. Using the periodicity assumption, the boundary conditions for the unit cell are derived. The homogenized stiffness matrix is determined in elastic and plastic range. A numerical example to study the effect of the volume fraction of fibers is introduced. |
| Keywords | fiber reinforced concrete composite materials homogenization periodicity finite element |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2006-03-15 |
| Volume | volume11 |
| Issue | issue1 |
| Start Page | 43 |
| End Page | 49 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313548 |
