A Simple Membrane Computing Method for Simulating Bio-Chemical Reactions

There are two formalisms for simulating spatially homogeneous chemical system; the deterministic approach, usually based on differential equations (reaction rate equations) and the stochastic approach which is based on a single differential-difference equation (the master equation). The stochastic approach has a firmer physical basis than the deterministic approach, but the master equation is often mathematically intractable. Thus, a method was proposed to make exact numerical calculations within the framework of the stochastic formulation without having to deal with the master equation directly. However, its drawback remains in great amount of computer time that is often required to simulate a desired amount of system time. A novel method that we propose is Deterministic Abstract Rewriting System on Multisets (DARMS), which is a deterministic approach based on an approximate procedure of an exact stochastic method. DARMS can produce significant gains in simulation speed with acceptable losses in accuracy. DARMS is a class of P Systems in which reaction rules are applied in parallel and deterministically. The feasibility and utility of DARMS are demonstrated by applying it to the Oregonator, which is a well-known model of the Belousov-Zhabotinskii (BZ) reaction. We also consider 1-dimensional and 2-dimensional cellular automata composed of DARMS and confirm that it can exhibit typical pattern formations of the BZ reaction. Since DARMS is a deterministic approach, it ignores the inherent fluctuations and correlations in chemical reactions; they are not so significant in spatially homogeneous chemical reactions but significant in bio-chemical systems. Thus, we also propose a stochastic approach, Stochastic ARMS (SARMS); SARMS is not an exact stochastic approach, but an approximate procedure of the exact stochastic method

Molecular Remodeling of the Presynaptic Active Zone of Drosophila Photoreceptors via Activity-Dependent Feedback

SummaryNeural activity contributes to the regulation of the properties of synapses in sensory systems, allowing for adjustment to a changing environment. Little is known about how synaptic molecular components are regulated to achieve activity-dependent plasticity at central synapses. Here, we found that after prolonged exposure to natural ambient light the presynaptic active zone in Drosophila photoreceptors undergoes reversible remodeling, including loss of Bruchpilot, DLiprin-α, and DRBP, but not of DSyd-1 or Cacophony. The level of depolarization of the postsynaptic neurons is critical for the light-induced changes in active zone composition in the photoreceptors, indicating the existence of a feedback signal. In search of this signal, we have identified a crucial role of microtubule meshwork organization downstream of the divergent canonical Wnt pathway, potentially via Kinesin-3 Imac. These data reveal that active zone composition can be regulated in vivo and identify the underlying molecular machinery

Museum of Far Eastern Antiquities スウェーデン ショゾウ ノ イン シュウ セイドウキ ニツイテ イン コウキ セイシュウ ゼンキ ニオケル キンブン チュウゾウ ギホウ

研究ノー

殷代青銅器の生産体制

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 大貫 静夫, 東京大学教授 設楽 博己, 東京大学教授 早乙女 雅博, 南山大学教授 西江 清高, 東洋文庫研究員 飯島 武次University of Tokyo(東京大学

キムラ ブザン コレクション ニオケル チュウゴク チュウゲン セイドウキ キムラ ブザン ト チュウゴク ビジュツ コレクション

学習院大学東洋文化研究所一般研究プロジェクト「木村武山と中国美術コレクション」（研究代表者 鶴間和幸（文学部教授）、2017 ～ 2018年度）の研究成

法・犯罪・科学 : ニュージーランドにおける法科学ラボラトリーの民族誌

学位の種別: 課程博士審査委員会委員 : (主査)東京大学教授 福島 真人, 東京大学教授 橋本 敦彦, 東京大学教授 木村 忠正, 東京大学準教授 津田 浩司, 国際基督教大学上級準教授 山口 富子University of Tokyo(東京大学

Development and evaluation of dose calculation algorithm with a combination of Monte Carlo and point-kernel methods for boron neutron capture therapy

We developed a 'hybrid algorithm' that combines the Monte Carlo (MC) and point-kernel methods for fast dose calculation in boron neutron capture therapy. The objectives of this study were to experimentally verify the hybrid algorithm and to verify the calculation accuracy and time of a 'complementary approach' adopting both the hybrid algorithm and the full-energy MC method. In the latter verification, the results were compared with those obtained using the full-energy MC method alone. In the hybrid algorithm, the moderation process of neutrons is simulated using only the MC method, and the thermalization process is modeled as a kernel. The thermal neutron fluxes calculated using only this algorithm were compared with those measured in a cubic phantom. In addition, a complementary approach was used for dose calculation in a geometry simulating the head region, and its computation time and accuracy were verified. The experimental verification indicated that the thermal neutron fluxes calculated using only the hybrid algorithm reproduced the measured values at depths exceeding a few centimeters, whereas they overestimated those at shallower depths. Compared with the calculation using only the full-energy MC method, the complementary approach reduced the computation time by approximately half, maintaining nearly same accuracy. When focusing on the calculation only using the hybrid algorithm only for the boron dose attributed to the reaction of thermal neutrons, the computation time was expected to reduce by 95% compared with the calculation using only the full-energy MC method. In conclusion, modeling the thermalization process as a kernel was effective for reducing the computation time

Influence of Different Calcium Amendments upon Methane Emission under Na-salinized Paddy Soil

Symposium Pape

Influence of different Ca amendments on CH4 emission under Na-salinized paddy soil

Session 2: Nitrogen, Green House Gasses and Agricultur