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Search Results: 1 - 10 of 527 matches for " Daichi Tajima "
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Predicting Popularity of Twitter Accounts through the Discovery of Link-Propagating Early Adopters
Daichi Imamori,Keishi Tajima
Computer Science , 2015,
Abstract: In this paper, we propose a method of ranking recently created Twitter accounts according to their prospective popularity. Early detection of new promising accounts is useful for trend prediction, viral marketing, user recommendation, and so on. New accounts are, however, difficult to evaluate because they have not established their reputations, and we cannot apply existing link-based or other popularity-based account evaluation methods. Our method first finds "early adopters", i.e., users who often find new good information sources earlier than others. Our method then regards new accounts followed by good early adopters as promising, even if they do not have many followers now. In order to find good early adopters, we estimate the frequency of link propagation from each account, i.e., how many times the follow links from the account have been copied by its followers. If its followers have copied many of its follow links in the past, the account must be an early adopter, who find good information sources earlier than its followers. We develop a method of inferring which links are created by copying which links. One advantage of our method is that our method only uses information that can be easily obtained only by crawling neighbors of the target accounts in the current Twitter graph. We evaluated our method by an experiment on Twitter data. We chose then-new accounts from an old snapshot of Twitter, compute their ranking by our method, and compare it with the number of followers the accounts currently have. The result shows that our method produces better rankings than various baseline methods, especially for new accounts that have only a few followers.
Wrinkled 1 (WRI1) Homologs, AP2-Type Transcription Factors Involving Master Regulation of Seed Storage Oil Synthesis in Castor Bean (Ricinus communisL.)  [PDF]
Daichi Tajima, Ayami Kaneko, Masatsugu Sakamoto, Yumena Ito, Nong Thi Hue, Masayuki Miyazaki, Yushi Ishibashi, Takashi Yuasa, Mari Iwaya-Inoue
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.42044
Abstract: Among APETALA2 (AP2)-type plant specific transcription factor family, WRINKLED1 (WRI1), has appeared to be a master gene transcriptionally regulating a set of carbon metabolism- and fatty acid synthesis (FAS)-related genes responsible for seed specific triacylglycerols (TAGs) storage in oil plants. B3 type transcription factors, such as ABI3 and FUS3, are known to be involved in seed development, such as seed storage protein synthesis and maturation. Based on the recent whole genome sequence data of castor bean (Ricinus communis L.), putative WRI1 homologs (RcWRI1, RcWRI2) specifically expressed in castor bean seed have been identified by comparing organ specific expression profiles among seed development-related transcription factors, seed storage specific genes (Ricin, RcOleosin) and a set of FAS genes including genes for sucrose synthase (RcSUS2), biotin carboxyl carrier protein (a subunit of acetyl-CoA carboxylase, RcBCCP2) and ketoacyl-acyl carrier protein synthase (RcKAS1). Immunoreactive signals with WRI1, FUS3 and ABI5-related polypeptides were also detected in seed specifically, consistent with the expression profiles of seed development-related genes. The WRI1 binding consensus sites, [CnTnG](n)(7)[CG], designated as the AW-box, were found at the promoter region of RcBCCP2 and RcKAS1. Thus, RcWRI1 possibly play a pivotal role in seed specific TAGs storage during seed development by directly activating FAS -related genes.
The Validity of the Reduction of Disposable Plastic Checkout Bags in Japan  [PDF]
Masakazu Yamashita, Daichi Toyofuku
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.39118
Abstract: This study examined the effect of reducing disposable plastic checkout bags used in supermarkets, convenience stores, and so on in Japan. Considering that even when these checkout bags are abolished, alternative waste bags should be newly produced, because these checkout bags have been reused as household waste bags so far, and the corresponding amount of oil is still necessary to produce them, the amount of oil saved by this bag reduction was found to be 0.2 L/person/year at most. Further, it was demonstrated that the necessity to purchase substitute bags may increase the household and financial burden on consumers.
Induction of a bZIP Type Transcription Factor and Amino Acid Catabolism-Related Genes in Soybean Seedling in Response to Starvation Stress
Takashi Yuasa,Yuri Nagasawa,Katsumasa Osanai,Ayami Kaneko,Daichi Tajima,Nang Myint Phyu Sin Htwe,Yushi Ishibashi,Mari Iwaya-Inoue
Journal of Botany , 2013, DOI: 10.1155/2013/935479
Abstract: To address roles of bZIP transcription factors on regulation of amino acid catabolism under autophagy-induced plant cells, we examined the effect of nutrient starvation on the expression of low energy stress-related transcription factor homologs, GmbZIP53A and GmbZIP53B, and amino acid catabolism-related genes in soybean (Glycine max (L.) Merr.). Sucrose starvation treatment significantly enhanced the expressions of GmbZIP53A, but not GmbZIP53B asparagine synthase (GmASN1), proline dehydrogenase1 (GmProDH), and branched chain amino acid transaminase 3 (GmBCAT3). GmbZIP53-related immunoreactive signals were upregulated under severe starvation with sucrose starvation and protease inhibitors, while 3% sucrose and sucrose starvation had no or marginal effects on the signal. Profiles of induction of GmASN1, GmProDH and GmBCAT3 under various nutrient conditions were consistent with the profiles of GmbZIP53 protein levels but not with those of GmbZIP mRNA levels. These results indicate that GmbZIP53 proteins levels are regulated by posttranslational mechanism in response to severe starvation stress and that the increased protein of GmbZIP53 under severe starvation accelerates transcriptional induction of GmASN1, GmProDH, and GmBCAT3. Furthermore, it is conceivable that decrease of branched chain amino acid level by the BCAT-mediated degradation eventually enhances autophagy under severe starvation. 1. Introduction The perception and management of nutrient and energy levels in organisms are crucial for survival by adjusting metabolism to available resources. Recent studies revealed that sugar signals in higher plants activate various biological modules such as sugar sensor, transcription factors, sugar transporters, and metabolic enzymes of sugar and amino acids [1, 2]. In higher plants, sugar deprivation and/or low energy stress by decreased photosynthesis have appeared to induce protein degradation via autophagy and amino acid metabolism, leading to translocation of nutrients and senescence [3, 4]. Recently accumulated studies on bZIP type transcription factors of Arabidopsis concerning nutrient signal and amino acid metabolism have unveiled that a set of bZIP transcription factors, bZIP1 and bZIP53, classified to S-type subgroup among the bZIP superfamily, are master regulatory components in transcriptional induction of amino acid catabolism-related enzymes involved in low energy stress, sucrose starvation, and senescence-induced nutrient translocation [5–7]. Sucrose starvation and/or low energy stress activate bZIP1 and bZIP53a by transcriptional and
A generalization of the Artin-Tate formula for fourfolds
Daichi Kohmoto
Mathematics , 2010,
Abstract: We give a new formula for the special value at s=2 of the Hasse-Weil zeta function for smooth projective fourfolds under some assumptions (the Tate and Beilinson conjecture, finiteness of some cohomology groups, etc.). Our formula may be considered as a generalization of the Artin-Tate(-Milne) formula for smooth surfaces, and expresses the special zeta value almost exclusively in terms of inner geometric invariants such as higher Chow groups (motivic cohomology groups). Moreover we compare our formula with Geisser's formula for the same zeta value in terms of Weil-\'etale motivic cohomology groups, and as a consequence (under additional assumptions) we obtain some presentations of weight two Weil-\'etale motivic cohomology groups in terms of higher Chow groups and unramified cohomology groups.
An Application of Gamma Distribution to the Income Distribution and the Estimation of Potential Food Demand Functions  [PDF]
Shunsuke Mori, Daichi Nakata, Tomohiro Kaneda
Modern Economy (ME) , 2015, DOI: 10.4236/me.2015.69095
Abstract: Poverty and hunger are the central issues against the sustainable development. Today, more than 800 million people are suffering from insufficient nutrition according to FAO (FAO, 2010). However, on the other hand, it is often pointed out that the per capita food production already meets the demand for the per capita food requirement. The above contradictory observation suggests that many people cannot access the food market because of the low income. The availability of electricity and other energy is also the case. Since these issues are mainly caused by the inequity of income distribution, its quantitative analysis is indispensable to evaluate the societal policy towards the sustainable future. However, since the existing indicators such as Gini coefficients do not represent the income distribution explicitly, they fail to assess the effects of social policy for the improvement of purchasing power of poor people. Population of absolute poverty who gets less than 1.25 US dollar per day is also provided by World Bank. This indicator does not show the distribution pattern of middle to high income classes. The authors would thus point out the need for an alternative method. This paper describes an application of Gamma distribution to the income distribution patterns. The parameters are statistically estimated based on the income quintile data provided by World Bank. The results show how the income distribution has changed historically by country. Based on the future income distribution and the simulation results of the author’s crop market model, we evaluate the share of people who cannot afford the major crop. The authors also propose a procedure to estimate the potential food demand function considering the income distribution changes, suggesting that the future demand could be affected by not only the per-capita income growth but the income distribution changes.
Evaluation of Carbon Dioxide Absorption Characteristics Lithium Ortho-Silicate in Chemical Heat Storage  [PDF]
Takehiro Esaki, Daichi Iwase, Noriyuki Kobayashi
Journal of Materials Science and Chemical Engineering (MSCE) , 2017, DOI: 10.4236/msce.2017.54006
Abstract: We report the development of technology that may contribute to a reduction in greenhouse gas emissions and improve the energy efficiency of the CO2 capture process. Lithium ortho-silicate is a suitable solid sorbent for capturing CO2. This reversible chemical reaction is also applicable to chemical heat storage. The absorption reaction characteristics of lithium ortho-silicate were studied by a thermogravimetric method and a volumetric method that demonstrated the influence of heat and mass transfer limitations in a packed bed designed to be as small as possible. We developed a method for measuring the absorption reaction characteristics in the experiments. In the experiments, a constant conversion fraction of 60% was observed. The reaction system was stable to repetition. The CO2 absorption rate depends on the CO2 pressure and reactor temperature. The absorption rate was determined at several reactor temperatures when the conversion fraction was 0.3. In this study, the maximum absorption rate was obtained at 670oC. It was demonstrated that lithium ortho-silicate is suitable for use in a chemical heat storage system.
Effect of Low-Dose Sodium Bicarbonate Supplementation on Intermittent Endurance Performance  [PDF]
Sakura Tanaka, Daichi Yamaguchi, Shoji Igawa
Food and Nutrition Sciences (FNS) , 2018, DOI: 10.4236/fns.2018.911094
Abstract: In this study, we investigated the effect of sodium bicarbonate (NaHCO3) supplementation at a dose of 0.2 g·kg1 40 min before an exercise on intermittent endurance performance and gastrointestinal distress. The participants were six healthy male students of a university. The Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) was used for the evaluation of intermittent endurance. The participants ingested water (Cont) or NaHCO3 independently at three timings. After drinking water, the Yo-Yo IR1 was performed for 2 min as warm-up. After resting for 5 min, the Yo-Yo IR2 was initiated. The measurement items were exercise distance, nutrition intake, biochemical test results, and blood gas analysis findings. The participants who ingested NaHCO3 had a 14% extended distance than those who ingested Cont, and 2/3 of those who took NaHCO3 showed a better motor performance. No significant difference was observed between the participants who took Cont and NaHCO3 in terms of pH level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p < 0.05). No significant difference was observed between the participants who took Cont and NaHCO3 in terms of bicarbonate ion level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p < 0.05). In conclusion, even when the participants ingested NaHCO3 at a low dose (0.2 g·kg1), their exercise ability during an intermittent endurance test has improved. Furthermore, when digestive absorption is considered, eating a meal in advance may be able to suppress the onset of gastrointestinal distress.
In Vitro Analysis of VEGF and HGF Production by Fibroblast in Cultured Dermal Substitute Combined with EGF-Incorporating Top Dressing  [PDF]
Emi Iijima, Daichi Daichi Toyoda, Akiko Yamamoto, Misato Kuroyanagi, Yoshimitsu Yoshimitsu Kuroyanagi
Open Journal of Regenerative Medicine (OJRM) , 2014, DOI: 10.4236/ojrm.2014.31002
Abstract:

This study aimed to investigate the potential of cultured dermal substitute (CDS) to release angiogenic growth factors when laminated with a membrane containing epidermal growth factor (EGF) as a top dressing. Membranes were prepared by air-drying a solution of hyaluronic acid (HA) and collagen (Col) with or without EGF. Membranes were designed to contain EGF at concentrations of 0, 0.1, 0.2 or 0.5 μg/cm2. CDS was prepared by incorporating fibroblasts into a collagen gel combined with a cross-linked HA spongy matrix, followed by culturing for 5 days. CDS was designed to contain fibroblasts at a density of 2 × 105 (Group I) or 4 × 105 cells/cm2> (Group II). CDS was elevated at the interface between air and culture medium, on the top of which each membrane was placed. This culture system was employed as a wound surface model. Metabolic activity of the fibroblasts in the CDS cultured for 7 days on a wound surface model was measured by MTT assay. The amounts of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) after 7 days of cultivation were measured by using ELISA. Membranes containing EGF ranging from 0.1 to 0.5 μg/cm2> facilitated production of both VEGF and HGF, as compared with control membranes without EGF. However, a membrane containing EGF at a concentration of 0.5 μg/cm2> failed to facilitate fibroblast cytokine production in Group I. These results demonstrated that the EGF-incorporating membrane was able to stimulate fibroblasts in the CDS to synthesize an increased amount of VEGF and HGF in a dose-dependent manner.



Roles of triaxiality and residual interaction in signature inversions of A~130 odd-odd nuclei
N. Tajima
Physics , 1993, DOI: 10.1016/0375-9474(94)90180-5
Abstract: Rotational bands with (neutron h_11/2)^1 (proton h_11/2)^1 configurations are studied using a particle-rotor model in which a proton and a neutron quasiparticles interacting through a zero-range force are coupled with a triaxial rotor. It is shown for 124Cs that one can reproduce the signature dependence of energy and B(M1)/B(E2) ratio best when one takes into account gamma-deformations with irrotational-flow moment of inertia in addition to the proton-neutron interaction proposed by Semmes and Ragnarsson. Including both effects, a systematic calculation of signature splittings is performed for Cs, La isotopes and N=75 isotones to be compared with experiments. Discussions are also done on the deficiencies of the cranking model concerning its applicability to signature inversion phenomena in odd-odd nuclei.
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