Nature © Macmillan Publishers Ltd 19988 localizing effect will lead to saturation of the magnetoresistance. Yet all the data except for the perovskite manganites and the strongly localized Eu 0.99 Gd 0.01 Se (n ¼ 0:0002 per unit cell) are on samples that satisfy k F l Ͼ 1, indicating the weakly localizing nature of pure spin scattering, as expected.At low carrier densities, one should be wary of magnetizationdependent bandshift, because the exchange energy might be comparable to the Fermi energy. When the carriers are introduced by doping, this is not important, but for semimetals (Tl 2 Mn 2 O 7 may be an example 19,20 ) and mixed valent compounds 21 the carrier density itself might become field-and temperature-dependent.We conclude that on elementary theoretical grounds and with some support from the limited data available, the very simplest Born approximation gives a good account of the trends in bulk magnetoresistance over two decades in density, in materials and in models of magnetism that have otherwise very little in common. The most evident deviation from a simple scaling law is in the perovskite manganites, for which there is overwhelming evidence that their 'colossal' magnetoresistance arises from the localization of carriers by lattice distortions that are themselves coupled to the magnetic degrees of freedom.This organizing principle suggests that insulating ferromagnets, lightly doped into the metallic regime, are a promising class of materials in which to search for large bulk magnetoresistance. As a final cautionary note, we also point out that the scaling shown in equation (4) and in Fig. 1 nevertheless implies rather small values of the absolute bulk magnetoresistance at the millitesla fields of technological interest. Ⅺ

The old calendar of pollens did not reflect current pollen distribution and concentrations that can be influenced by changes of weather and environment of each region in South Korea. A new pollen calendar of allergenic pollens was made based on the data on pollen concentrations obtained in eight regions nationwide between 1997 and 2009. The distribution of pollen was assessed every day at 8 areas (Seoul, Guri, Busan, Daegu, Jeonju, Kwangju, Kangneung, and Jeju) for 12 years between July 1, 1997 and June 30, 2009. Pollens were collected by using Burkard 7-day sampler (Burkard Manufacturing Co Ltd, UK). Pollens which were stained with Calberla's fuchsin staining solution were identified and counted. Pine became the highest pollen in May, and the pollen concentrations of oak and birch also became high. Ragweed appeared in the middle of August and showed the highest pollen concentration in the middles of September. Japanese hop showed a high concentration between the middle of August and the end of September, and mugwort appeared in the middles of August and its concentration increased up until early September. In Kangneung, birch appeared earlier, pine showed a higher pollen concentration than in the other areas. In Daegu, Oriental thuja and alder produced a large concentration of pollens. Pine produced a large concentration of pollens between the middle of April and the end of May. Weeds showed higher concentrations in September and mugwort appeared earlier than ragweed. In Busan the time of flowering is relatively early, and alder and Oriental thuja appeared earliest among all areas. In Kwangju, Oriental thuja and hazelnut appeared in early February. Japanese cedar showed the highest pollen concentration in March in Jeju. In conclusion, update information on pollen calendar in South Korea should be provided for allergic patients through the website to manage and prevent the pollinosis.

Background It is unclear whether the responses of refractory and common Mycoplasma pneumoniae (MP) pneumonia to macrolides differ. Hence, this study aimed to identify biomarkers that may be used to distinguish refractory and common pneumonias caused by MP in children at hospital admission. Methods The study included 123 children divided into five groups according to infection agent and treatment protocol: Group I included those with MP infection without documented viral infection, treated with only macrolides; Group II included those with MP infection without documented viral infection, treated with a combination of macrolides and methylprednisolone; Group III included those with MP infection and documented viral infection, treated with only macrolides; Group IV included those with viral pneumonia without documented MP infection; Group V was the control group composed of admitted children without MP or a documented viral infection. These five groups were further subdivided into Groups A (including Groups I, III, IV, and V) and B (Group II) according to the responses to macrolide treatment. Concentrations of cytokines interleukin 6, interleukin 17, interleukin 18, and tumor necrosis factor-α, and lactate dehydrogenase, and ferritin of all children were evaluated, and these levels were compared among the groups. Statistical comparisons were made using Kruskal Wallis test and Mann-Whitney U test. Results Serum lactate dehydrogenase, interleukin 18, and ferritin concentrations were significantly higher in Group II than in Groups I, III, IV, and V and were significantly higher in Group B than in Group A. When the serum lactate dehydrogenase concentration was 350 IU/L or higher, the sensitivity and specificity for diagnosing refractory MP pneumonia were 73 and 80%, respectively. When the interleukin 18 level was 360 pg/mL or higher, the sensitivity and specificity for diagnosing refractory MP pneumonia were 93 and 70%, respectively. When the ferritin level was 230 pg/mL or higher, the sensitivity and specificity for diagnosing refractory MP pneumonia were 67 and 67%, respectively. Conclusion These results suggest that serum lactate dehydrogenase, interleukin 18, and ferritin constitute the critical combination of biomarkers useful for predicting refractory MP pneumonia in children at hospital admission.

Abstract. The diurnal pattern of the vertical distribution of biogenic pollen in the lower troposphere was investigated by LIDAR. Meteorological data were taken at the ground. Pollen concentrations were measured at the surface using a Burkard 7-day-recording volumetric spore sampler. Aerosol extinction coefficients and depolarization ratios at 532 nm were obtained from LIDAR measurements in spring (4 May–2 June) 2009 in Gwangju, South Korea. Linear volume depolarization ratios varied between 0.08 and 0.14 and were observed only during daytime (09:00–17:00 local time (LT)) during days of high pollen concentration (4 to 9 May). Daily average pollen concentrations ranged 1000–2500 cm−3 in the same period. The temporal evolution of the vertical distribution of the linear volume depolarization ratio showed a specific diurnal pattern. Linear volume depolarization ratios of more than 0.06, were measured near the surface in the morning. High depolarization ratios were detected up to 2 km aboveground between 12:00 and 14:00 LT, whereas high depolarization ratios were observed only close to the surface after 17:00 LT. Low values of depolarization ratios (≤0.05) were detected after 18:00 LT until the next morning. During the measurement period, the daily variations of the high depolarization ratios close to the surface showed correlation to number concentration measurements of pollen. This finding suggests that high depolarization ratios could be attributed to enhanced pollen concentrations. The diurnal characteristics of the high values of depolarization ratios are thought to be closely associated with turbulent transport. Diurnal and vertical characteristics of pollen, if measured continuously, could be used to improve the accuracy of pollen-forecasting models via data assimilation studies.

The aim of this study is to investigate the nationwide incidence and treatment pattern of retinopathy of prematurity (ROP) in South Korea. Using the population-based National Health Insurance database (2007–2018), the nationwide incidence of ROP among premature infants with a gestational age (GA) < 37 weeks (GA < 28 weeks, GA28; 28 weeks ≤ GA < 37 weeks; GA28-37) and the percentage of ROP infants who underwent treatment [surgery (vitrectomy, encircling/buckling); retinal ablation (laser photocoagulation, cryotherapy)] were evaluated. We identified 141,964 premature infants, 42,300 of whom had ROP, with a nationwide incidence of 29.8%. The incidence of ROP in GA28 group was 4.3 times higher than in GA28-37 group (63.6% [2240/3522] vs 28.9% [40,060/138,442], p < 0.001). As for the 12-year trends, the incidence of ROP decreased from 39.5% (3308/8366) in 2007 to 23.5% (2943/12,539) in 2018. 3.0% of ROP infants underwent treatment (25.0% in GA28; 1.7% in GA28-37); 0.2% (84/42,300) and 2.9% (1214/42,300) underwent surgery and retinal ablation, respectively. The overall percentage of ROP infants who underwent treatment has decreased from 4.7% in 2007 to 1.8% in 2018. This first Korean nationwide epidemiological study of ROP revealed a decreased incidence of ROP and a decreased percentage of ROP infants undergoing conventional treatment during a 12-year period.