Minimal Model of Stochastic Athermal Systems: Origin of Non-Gaussian Noise

For a wide class of stochastic athermal systems, we derive Langevin-like equations driven by non-Gaussian noise, starting from master equations and developing a new asymptotic expansion. We found an explicit condition whereby the non-Gaussian properties of the athermal noise become dominant for tracer particles associated with both thermal and athermal environments. Furthermore, we derive an inverse formula to infer microscopic properties of the athermal bath from the statistics of the tracer particle. We apply our formulation to a granular motor under viscous friction, and analytically obtain the angular velocity distribution function. Our theory demonstrates that the non-Gaussian Langevin equation is the minimal model of athermal systems.Comment: 10 pages, 5 figure

Dry Small Pleural Dissemination of Adenocarcinoma of the Lung Preoperatively Detected by PET/CT: A Report of Two Cases

Dry pleural dissemination in non-small cell lung cancer, defined as solid pleural metastasis of lung cancer without pleural eff usion, is a condition occurring in T4 lung cancer. Positron emission tomography (PET) has been reported to be useful for the diagnosis and staging of lung cancer. It has been reported that positive findings on PET scans of indeterminate pleural abnormalities at computed tomography (CT) are sensitive to malignancy. We encountered two cases of dry small pleural dissemination of adenocarcinoma of the lung preoperatively detected by PET/CT. A 75-year-old man and a 66-year-old man underwent CT scan, which demonstrated solitary tumor in the lung, an enlarged mediastinal lymph node, and a small pleural nodule less than 10 mm in size, all of which were positive findings on the fluorine 18 fluorodeoxyglucose (FDG) PET portion of an integrated PET/CT. Both patients underwent thoracoscopic biopsy of the dry pleural nodule revealing dissemination of adenocarcinoma of the lung (T4). Whereas histological thoracoscopic diagnosis remains mandatory before planning treatment, our cases may suggest that PET/CT will be useful as a screening modality for dry pleural dissemination of lung cancer.</p

Decentralized navigation and collision avoidance for robotic swarm with heterogeneous abilities

This paper proposes a decentralized navigation method with collision avoidance for a robotic swarm whose individuals possess heterogeneous abilities, such as sensing range and maximum speed. In this method, each agent distributedly constructs and maintains a local directed connection with another agent using only local information, which is relative distance. Moreover, all agents always maintain some distance from other agents to avoid collision. As a result, one leader robot can guide an entire swarm of robots to their destination, and the other robots can follow the leader while maintaining connectivity and not colliding with others. We prove the above mathematically, and we demonstrate the validity of the proposed method by numerical simulation and experimentation

Preliminary experiment of in-channel transient storage in a deciduous broadleaved forest

山地河川の流路内における流水の一時滞留現象を明らかにするために, 中国山地中央部の落葉広葉樹林内を流れる小河川においてNaClトレーサーを用いた予備実験を行った. 実験に際し, まずNaClトレーサーを一定強度で流路内へ注入するための器械（マリオットボトル方式の注入器, MBI）を自作し, 注入強度の安定性を確かめた. その結果, 平均注入強度が約1.5ml/sの条件において変動係数は0.5%未満であり, MBIの安定性は良好であった. 次いで, 長さ約25mの調査区間の上流端から約4時間に渡り, NaClトレーサーを注入し, 下流端での電気伝導度(EC)の変化を調べた. この注入実験を落葉期の直前と直後に1回ずつ行った結果, 1)落葉直後は直前よりもNaClトレーサーの下流端への到達速度が遅いこと, 2)流量の日変化がECに影響を与えること, 3)ECの上昇区間においてスパイク状の変化が現れる場合があること, 及び4)注入停止から1時間ではECは一定にならないことがわかった. 流量条件によってはこれらとは異なる結果が予想されるが, 今後本調査地においてNaClトレーサーの注入実験や流水に関する理論的解析に基づいて一時滞留現象を明らかにしようとする際に, 今回の予備実験の結果は一つの目安となる