Power-law distribution found in city-scale traffic flow simulation

Origin of a power-law in traffic-volume distribution found in traffic simulations of Kobe city was studied. The traffic distribution which was obtained from a shortest path search with randomized OD (origin-destination) set in Kobe city digital map obeys power-law. The toy model that Cayley tree is embedded in the network is also verified. It is theoretically shown that the traffic distribution with all possible OD set in a Cayley tree obeys power-law like distribution. With randomized OD set, the distribution is diffused from the theoretical point sets. Relationship between these facts and the origin of power-law is discussed.

Impact of the State of Emergency during the COVID-19 Pandemic in 2020 on Asthma Exacerbations among Children in Kobe City, Japan

The coronavirus disease (COVID-19) pandemic altered environmental factors. We studied the impact of these changes on asthma exacerbation (AE) by comparing the AE-related environmental factors between COVID-19 (2020) and pre-COVID-19 (2011–2019) eras. Between 2011 and 2020, 278,465 children (<16 years old) visited our emergency department, and 7476 were diagnosed with AE. The number of patients showed spring and fall peaks in 2011–2019. Multivariate analyses showed significant positive relationships of the number of AE patients with the average temperature among all patients and 0–5-year-olds and with sulfur dioxide (SO2) levels in 2011–2019 among 0–5-year-olds. Although the spring peak in the number of patients was not observed in 2020 after declaration of a state of emergency, the fall peak was again observed after the state of emergency was lifted. No changes in average temperature were detected, but SO2 was significantly reduced following declaration of the state of emergency in 2020. Therefore, SO2 reduction might have contributed to the disappearance of the peak of AE. However, a fall peak was observed again in 2020, although SO2 levels continued to be low. These data suggest that person to person interaction seems to be associated with AE, presumably due to unknown viral infections.

Clinical Diagnosis of Toxoplasmosis via Histopathological and Antibody Examination of Five Immunocompetent Patients at Kobe City Medical Center General Hospital, 2008 to 2015

Congenital toxoplasmosis, commonly known as TORCH, is a well-known syndrome, but even experienced obstetricians rarely encounter it. In Japan, there is good overall hygiene and raw or wild game meats are not eaten; therefore, the prevalence of Toxoplasma gondii infection and the antibody positivity rates have been low. This low prevalence rate also relates to the fact that Toxoplasma gondii infections are rarely observed in immunocompetent hosts. Exploration of the cases in which pathological examinations were performed at our hospital (Kobe City Medical Center General Hospital) revealed that acquired Toxoplasma infections were apparent in five immunocompetent patients over an 8-year period. The number of infections was unexpectedly high. The number of 5 cases was the highest in literature review to the extent that we could know. To prevent congenital toxoplasmosis, which manifests as intracranial calcifications, hydrocephalus, and chorioretinitis in severe cases, pregnant women and their doctors require proper knowledge about the risk factors and danger of this infection. We believe that from the viewpoint of cost performance relationship, it is appropriate to bear the test fee of about 50 USD for Toxoplasma IgG and IgM check for the test of congenital toxoplasmosis, if patients desired.

Multivariate analysis of the impact of weather and air pollution on emergency department visits for night-time headaches among children: retrospective, clinical observational study

ObjectivesTo examine the association between the number of visits to the emergency department (ED) by children for night-time headaches and exposure to multifaceted factors, such as meteorological conditions and air pollution.DesignWe conducted a clinical observational time-series analysis study.SettingWe reviewed consecutive patients younger than 16 years of age at the primary ED centre in Kobe city, Japan, during the night shift (19:30–7:00 hours) between 1 January 2011 and 31 December 2019.ParticipantsIn total, 265 191 children visited the ED; 822 presented with headache during the study period.Primary outcome measuresWe investigated the effects of meteorological factors and air pollutants by multivariate analysis of Poisson regression estimates. A subanalysis included the relationship between the number of patients with night-time headaches and the above factors by sex. Furthermore, the effect of typhoon landing on patient visits for headache was also analysed. Headache was not classified because examinations were performed by general paediatricians (non-specialists).ResultsThe number of patients with night-time headaches displayed distinct seasonal changes, with peaks during the summer. Multivariate analysis of Poisson regression estimates revealed a significant positive relationship between the number of patients for headache and mean temperature. Subanalysis by sex indicated a positive relationship between the number of patients with headache and mean temperature in both sexes; however, it was significant only for females. No relationship was found between the number of patients with headache and air pollution. There was no change in the number of patients for night-time headaches 3 days before and after typhoon landing.ConclusionsHigh temperature is the main factor for visiting ED for night-time headaches among children in Kobe city. Our results suggest that preventive measures against night-time headaches may be possible by reducing time spent outside during summer.