Real quadratic fields admitting universal lattices of rank7

In this paper, we will prove that if $d$ is sufficiently large square-free positive rational integer, then there is no integral septenary universal quadratic lattice over $\mathcal{O}_F$ where $F=\mathbb Q(\sqrt{d})$

The Effects of Air Pollution on Mortality in South Korea

AbstractIt is well known that air pollution has the negative effect on human health. This study is dealt with the relationship between air pollutant level and standardized mortality between 2005 and 2013 in Korea. The standardized mortality are collected by the 251 administrative districts using KOSIS (Korean Statistical Information Service) and the air pollutant data collected from air pollutant monitoring sites. The statistical interpolation technique is adapted to solve the problem of spatial misalignment between air pollutant and administrative districts. In addition, SaTScan is used to detecting the high relatively risk area based on spatial and temporal characteristics. It can help determining other external factors to mortality

Acute dystonia by droperidol during intravenous patient-controlled analgesia in young patients.

Patient-controlled analgesia (PCA) is an important means for postoperative analgesia with parenteral opioid. However, postoperative nausea and vomiting (PONV) remains a major problem with a PCA system. Droperidol is used in PCA to prevent PONV. Extrapyramidal reactions by droperidol are, however, occasionally induced. We describe two cases of severe extrapyramidal hypertonic syndrome with an intravenous administration of droperidol in PCA in young patients, following orthopedic surgery

Factors affecting customer loyalty of mobile RFID services in Korea

Mobile radio frequency identification (RFID) services are expected to be launched in full-scale as a new service option in the telecommunications service market following the development of RFID technology and maturation of the IT infrastructure. Importance of customer loyalty has been widely recognized in business marketing for a long time, and the customer loyalty enhancement strategies for mobile RFID services is of significance to telecommunication carriers in terms of new business value creation. This study identifies the factors affecting customer loyalty for mobile RFID services and presents telecommunication service managers with information useful for improving customer loyalty for related new services. The data was collected from customers with some experience in the use of mobile RFID services through an online survey for an empirical analysis. And the collected data was analysed with structural equation model to verify the cause and effect relationship among perceived quality, switching cost, perceived value, customer satisfaction, switching barrier and customer relationship. The analysis showed that the quality of tag recognition and content quality proved to have a direct impact on the customer satisfaction, whereas connection quality and ease of use would rather indirectly than directly influence customer satisfaction by perceived value. Perceived value and satisfaction affected the loyalty. Adaptation cost affects switching barriers, the higher the switching barriers, the stronger the loyalty. Based on the results of the empirical analysis, practical implications were given. What is more, mobile RFID customers were divided into two groups that are favourably and unfavourably disposed toward the service, and suggested customer loyalty improvement strategies adapted for each group

A contribution to the Reinhart and Rogoff debate: not 90 percent but maybe 30 percent

Using the Reinhart-Rogoff dataset, we find a debt threshold not around 90 percent but around 30 percent above which the median real GDP growth falls abruptly. Our work is the first to formally test for threshold effects in the relationship between public debt and median real GDP growth. The null hypothesis of no threshold effect is rejected at the 5 percent significance level for most cases. While we find no evidence of a threshold around 90 percent, our findings suggest that the debt threshold for economic growth may exist around a relatively small debt-to-GDP ratio of 30 percent. Empirical results are more robust with the postwar sample than the long sample that goes before World War II

Optical Spectroscopy of Supernova Remnants in M81 and M82

We present spectroscopy of 28 SNR candidates as well as one H II region in M81, and two SNR candidates in M82. Twenty six out of the M81 candidates turn out to be genuine SNRs, and two in M82 may be shocked condensations in the galactic outflow or SNRs. The distribution of [N II]/H{\alpha} ratios of M81 SNRs is bimodal. M81 SNRs are divided into two groups in the spectral line ratio diagrams: an [O III]-strong group and an [O III]-weak group. The latter have larger sizes, and may have faster shock velocity. [N II]/H{\alpha} ratios of the SNRs show a strong correlation with [S II]/H{\alpha} ratios. They show a clear radial gradient in [N II]/H{\alpha} and [S II]/H{\alpha} ratios: dLog ([N II]/H{\alpha})/dLog R = -0.018 {\pm} 0.008 dex/kpc and dLog ([S II]/H{\alpha})/dLog R = -0.016 {\pm} 0.008 dex/kpc where R is a deprojected galactocentric distance. We estimate the nitrogen and oxygen abundance of the SNRs from the comparison with shock-ionization models. We obtain a value for the nitrogen radial gradient, dLog(N/H)/dLogR = -0.023 {\pm} 0.009 dex/kpc, and little evidence for the gradient in oxygen. This nitrogen abundance shows a few times flatter gradient than those of the planetary nebulae and H II regions. We find that five SNRs are matched with X-ray sources. Their X-ray hardness colors are consistent with thermal SNRs.Comment: 19 pages, 24 figures, 5 tables, ApJ accepte