Spatial Period-Doubling Agglomeration of a Core-Periphery Model with a System of Cities

The orientation and progress of spatial agglomeration for Krugman's core--periphery model are investigated in this paper. Possible agglomeration patterns for a system of cities spread uniformly on a circle are set forth theoretically. For example, a possible and most likely course predicted for eight cities is a gradual and successive one---concentration into four cities and then into two cities en route to a single city. The existence of this course is ensured by numerical simulation for the model. Such gradual and successive agglomeration, which is called spatial-period doubling, presents a sharp contrast with the agglomeration of two cities, for which spontaneous concentration to a single city is observed in models of various kinds. It exercises caution about the adequacy of the two cities as a platform of the spatial agglomerations and demonstrates the need of the study on a system of cities

Spatial Period-Doubling Agglomeration of a Core-Periphery Model with a System of Cities

The orientation and progress of spatial agglomeration for Krugman's core--periphery model are investigated in this paper. Possible agglomeration patterns for a system of cities spread uniformly on a circle are set forth theoretically. For example, a possible and most likely course predicted for eight cities is a gradual and successive one---concentration into four cities and then into two cities en route to a single city. The existence of this course is ensured by numerical simulation for the model. Such gradual and successive agglomeration, which is called spatial-period doubling, presents a sharp contrast with the agglomeration of two cities, for which spontaneous concentration to a single city is observed in models of various kinds. It exercises caution about the adequacy of the two cities as a platform of the spatial agglomerations and demonstrates the need of the study on a system of cities.Agglomeration of population; Bifurcation; Core-periphery model; Group theory; Spatial period doubling

Characterizing scale dependence of effective diffusion driven by fluid flows

We study the scale dependence of effective diffusion of fluid tracers, specifically, its dependence on the P\'{e}clet number, a dimensionless parameter of the ratio between advection and molecular diffusion. Here, we address the case that length and time scales on which the effective diffusion can be described are not separated from those of advection and molecular diffusion. For this, we propose a new method for characterizing the effective diffusivity without relying on the scale separation. For a given spatial domain inside which the effective diffusion can emerge, a time constant related to the diffusion is identified by considering the spatio-temporal evolution of a test advection-diffusion equation, where its initial condition is set at a pulse function. Then, the value of effective diffusivity is identified by minimizing the $L_\infty$ distance between solutions of the above test equation and the diffusion one with mean drift. With this method, for time-independent gyre and time-periodic shear flows, we numerically show that the scale dependence of the effective diffusivity changes beyond the conventional theoretical regime. Their kinematic origins are revealed as the development of the molecular diffusion across flow cells of the gyre and as the suppression of the drift motion due to a temporal oscillation in the shear.Comment: 10 pages, 4 figure

頭頸部癌患者へのシスプラチン誘発化学性嘔気に対するフォスアプレピタント、パラノセトロン併用低用量ステロイドについて

広島大学(Hiroshima University)博士(医学)Doctor of Philosophy in Medical Sciencedoctora

Baseline Neutrophil-to-Lymphocyte Ratio and Glasgow Prognostic Score are Associated with Clinical Outcome in Patients with Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma Treated with Nivolumab

Recurrent or metastatic head and neck squamous cell carcinoma (R/MHNSCC) has a poor prognosis. Although nivolumab is approved in Japan for treating R/MHNSCC, the response rate is low. Therefore, identifying pretreatment prognostic factors is necessary. This study assessed the utility of the neutrophil-to-lymphocyte ratio (NLR) and Glasgow Prognostic Score (GPS) as biomarkers of response to nivolumab. We retrospectively collected the data of 56 R/MHNSCC patients treated with nivolumab between May 2017 and December 2019. The Kaplan–Meier method and log-rank test were used to estimate overall survival (OS) and progression-free survival (PFS), and multivariate Cox hazard regression analysis was used to identify independent predictors of survival. Patients with a low pretreatment NLR had prolonged OS, and patients with a low pretreatment GPS had increased OS and PFS. A performance score (PS) of 0-1, development of immune-related adverse events, and GPS of 0-1 were significantly associated with OS in multivariate analysis. In summary, baseline pretreatment NLR and GPS are independently associated with OS in R/MHNSCC patients treated with nivolumab. Administration of nivolumab while maintaining the PS reflects a immune status of the host and leads to a good OS

A Case of Primary Osteosarcoma of the Mandible That Responded to Preoperative Chemotherapy: p16 as a Potential Prognostic Factor

We report a case of mandibular osteosarcoma in a Japanese woman in her 70s who was p16-positive. Despite the rapid growth of the tumor, the patient responded well to chemotherapy and was then able to undergo surgery. Head and neck osteosarcoma (HNOS) is a very rare cancer, and although the importance of surgery has been pointed out, the effectiveness of chemotherapy is unclear. Resection margin negativity and response to chemotherapy have been reported as prognostic factors; another report assessed the effectiveness of the immunohistochemical expression of p16 protein as a predictor of response to chemotherapy

Prospective randomized efficacy of ultrasound-guided foam sclerotherapy compared with ultrasound-guided liquid sclerotherapy in the treatment of symptomatic venous malformations

ObjectiveTo compare the clinical outcome between ultrasound-guided foam sclerotherapy (UGFS) and ultrasound-guided liquid form sclerotherapy (UGLS) in patients with venous malformations (VM).MethodsEighty-nine patients with symptomatic VM were treated with ultrasound-guided sclerotherapy. There were 22 males and 67 females with mean age of 14.5 years. The sclerosing agents used were 1% polidocanol (POL) or 10% ethanolamine oleate (EO). POL was injected predominantly into smaller, superficial lesions, whereas EO was used for large, deeper lesions. Foam sclerosing solution was provided using Tessari’s method. Patients were randomized to receive either UGFS or UGLS. Post-sclerotherapy surveillance was done at 6 months after last session using duplex ultrasound. Findings obtained by duplex scanning were divided into four groups: (1) disappeared group: the venous space was occluded and was totally shrunk; (2) partially recanalized group: the venous space was partially recanalized and was partially shrunk; (3) totally recanalized group: the venous space was totally recanalized and returned at the same size; and (4) worsened group: the venous space was totally recanalized and became worse.ResultsForty-nine patients were treated with UGFS and the remaining 40 were treated with UGLS. There were no significant differences in age and men:women ratio. There was no significant difference in the anatomic distribution of VMs between the two groups. The amount of POL was significantly smaller in patients who were treated with UGFS (P = .022). Similarly, there was a significant reduction in the use of EO in patients treated with UGFS (P = .005). The proportion of VM with total disappearance and partial recanalization was significantly higher in patients treated with UGFS (P = .002). No major complications related to sclerotherapy were encountered in both groups.ConclusionsThese findings suggest that UGFS could have greater promise compared with UGLS in the treatment of VMs

Spatial Period-Doubling Agglomeration of a Core-Periphery Model with a System of Cities

The orientation and progress of spatial agglomeration for Krugman's core--periphery model are investigated in this paper. Possible agglomeration patterns for a system of cities spread uniformly on a circle are set forth theoretically. For example, a possible and most likely course predicted for eight cities is a gradual and successive one---concentration into four cities and then into two cities en route to a single city. The existence of this course is ensured by numerical simulation for the model. Such gradual and successive agglomeration, which is called spatial-period doubling, presents a sharp contrast with the agglomeration of two cities, for which spontaneous concentration to a single city is observed in models of various kinds. It exercises caution about the adequacy of the two cities as a platform of the spatial agglomerations and demonstrates the need of the study on a system of cities