Generalized gravity model for human migration

The gravity model (GM) analogous to Newton's law of universal gravitation has successfully described the flow between different spatial regions, such as human migration, traffic flows, international economic trades, etc. This simple but powerful approach relies only on the 'mass' factor represented by the scale of the regions and the 'geometrical' factor represented by the geographical distance. However, when the population has a subpopulation structure distinguished by different attributes, the estimation of the flow solely from the coarse-grained geographical factors in the GM causes the loss of differential geographical information for each attribute. To exploit the full information contained in the geographical information of subpopulation structure, we generalize the GM for population flow by explicitly harnessing the subpopulation properties characterized by both attributes and geography. As a concrete example, we examine the marriage patterns between the bride and the groom clans of Korea in the past. By exploiting more refined geographical and clan information, our generalized GM properly describes the real data, a part of which could not be explained by the conventional GM. Therefore, we would like to emphasize the necessity of using our generalized version of the GM, when the information on such nongeographical subpopulation structures is available.Comment: 14 pages, 6 figures, 2 table

Matchmaker, Matchmaker, Make Me a Match: Migration of Populations via Marriages in the Past

The study of human mobility is both of fundamental importance and of great potential value. For example, it can be leveraged to facilitate efficient city planning and improve prevention strategies when faced with epidemics. The newfound wealth of rich sources of data---including banknote flows, mobile phone records, and transportation data---has led to an explosion of attempts to characterize modern human mobility. Unfortunately, the dearth of comparable historical data makes it much more difficult to study human mobility patterns from the past. In this paper, we present an analysis of long-term human migration, which is important for processes such as urbanization and the spread of ideas. We demonstrate that the data record from Korean family books (called "jokbo") can be used to estimate migration patterns via marriages from the past 750 years. We apply two generative models of long-term human mobility to quantify the relevance of geographical information to human marriage records in the data, and we find that the wide variety in the geographical distributions of the clans poses interesting challenges for the direct application of these models. Using the different geographical distributions of clans, we quantify the "ergodicity" of clans in terms of how widely and uniformly they have spread across Korea, and we compare these results to those obtained using surname data from the Czech Republic. To examine population flow in more detail, we also construct and examine a population-flow network between regions. Based on the correlation between ergodicity and migration in Korea, we identify two different types of migration patterns: diffusive and convective. We expect the analysis of diffusive versus convective effects in population flows to be widely applicable to the study of mobility and migration patterns across different cultures.Comment: 24 pages, 23 figures, 5 table

Malignancies in Korean Patients with Inflammatory Myopathy

The aim of this study was to assess the prevalence and the common type of malignancies in Korean patients with polymyositis (PM) and dermatomyositis (DM) and to evaluate the differences of clinical and laboratory findings between patients with malignancy and those without malignancy. Forty-one Korean patients, who were diagnosed as PM or DM, were enrolled in this study. They fulfilled the Bohan and Peter's criteria for a definite diagnosis of PM and DM. Patients with PM were 25 and those with DM were 16. Eleven out of 41 patients (26.8%) had malignancies. The malignancy was diagnosed simultaneously or later in 81.8% of patients with inflammatory myopathy (IM). The breast cancer was the most common malignancy. In this study, forty three years old as a screening age for malignancy had 88.9% sensitivity and 50.2% specificity. The serum levels of creatine kinase (CK) were significantly lower in patients with malignancy than those without malignancy

Availability of hairy vetch (Vicia villosa Roth) as leguminous green manure crops for organic rice in reclaimed saline land

Hairy vetch (Vicia villosa) is playing an important role to improve soil physical properties and soil fertility for the supply of crop nutrients and this crop is also used as a representative legumes green manure for the production of organic agricultural food. In this study we evaluated the availability of hairy vetch in reclaimed organic rice cultivation. The response to increasing salinity was analyzed by means of the germination rate and seedling growth of hairy vetch. Results showed that seed germination of hairy vetch decreased insignificantly up to concentration of 0.6% NaCl. However, shoot and root growth of hairy vetch showed significant reduction at salinity concentrations higher than 0.1% NaCl level. In these results we were considered that hairy vetch can be use under concentration of 0.1% salinity as green manure for reclaimed saline agriculture

A Clinical Observation of Delayed Neurologic Deterioration Following Carbon Monoxide Poisoning

Some patients with anoxic exposure develop new neurologic deficits after periods of delay when they recover from the initial anoxia. This Delayed Neurologic Deterioration(DND) is most commonly seen following carbon monoxidelf'O) poisoning. This study was done to further describe the clinical features of this interesting but rare entity. We reviewed the records and brain scans of 37 patients who were admitted to Seoul National University Hospital because of DND following CO poisoning during the period January 1980 to December 1986. On reviewing the data, we were able to see certain patterns. Age may be important in the development of DND. Most patients were in their 40's to 60's. Patients with severe CO poisoning may be at higher risk of developing DND. However many patients with DND had brief periods of unconsciousness during acute poisoning. The lucid interval was usually 1-4 weeks. Long lucid interval may predict good prognosis. Global encephalopathy was the most common. Post-CO Parkinsonism was diagnosed in 5. Parkinsonism was part of global encephalopathy. They improved with L-dopa better than with anticholinergics. Low density in the globus pallidus may not be associated with Parkinsonism. Diffuse brain atrophy was the most common radiological finding

A STUDY ON THE TWO-ROW EFFECT IN THE SLOSHING PHENOMENON

In this study, changes in fluid impact loads inside a tank were examined according to a two-row tank arrangement in an LNG-FPSO (Liquefied Natural Gas-Floating Production Storage Offloading) vessel. The motion RAO (Response Amplitude Operator) of the LNG-FPSO, coupled with the sloshing phenomenon inside the tank, was calculated by using HydroStar by Bureau Veritas. The motion simulation in the tank was conducted under filling ratios of 30%H, 60%H, and 80%H. The RAO in each condition was calculated according to the one-row and the two-row tank arrangement. The motion response spectrum using the calculated RAO and the JONSWAP (Joint North Sea Wave Analysis Project) spectrum were computed by implementing irregular motion according to each filling ratio and tank arrangement. The sloshing phenomenon inside the tank was implemented by using a 6-DOF (Degree Of Freedom) sloshing motion platform; impact pressure on the walls of the tank was measured with pressure sensors installed inside the tank. The sloshing experiment was conducted under the three filling ratios in the one-row and the two-row tank arrangement and impact loads were compared under each filling ratio according to the one-row and the two-row tank arrangement

Traumatic Tricuspid Regurgitation Following Cardiac Massage

We report a 66-yr-old male patient who developed tricuspid regurgitation secondary to internal cardiac massage. After uneventful off-pump coronary artery bypass surgery, the subject experienced cardiac arrest in the intensive care unit. External cardiac massage was initiated and internal cardiac massage was performed eventually. A transesophageal echocardiography revealed avulsion of the anterior papillary muscle and chordae to the anterior leaflet after successful cardiopulmonary resuscitation. Emergency repair of the papillary muscle was performed under cardiopulmonary bypass