Pulsar Magnetosphere : A General Relativistic Treatment

A fully general relativistic description of the pulsar magnetosphere is provided. To be more concrete, a study of the pulsar magnetosphere is performed in the context of general relativistic magnetohydrodynamics (MHD) employing the so-called Grad-Shafranov approach. Not surprisingly, the resulting Grad-Shafranov equations and all the other related general relativistic MHD equations turn out to take essentially the same structures as those for the (rotating) black hole magnetosphere. Other different natures between the two cases including the structure of singular surfaces of MHD flows in each magnetosphere are essentially encoded in the different spacetime (metric) contents. In this way, the pulsar and the black hole magnetospheres can be described in an unified fashion. Particularly, the direction of poloidal currents circulating in the neutron star magnetosphere turns out to be the same as that of currents circulating in the black hole magnetosphere which, in turn, leads to the pulsar and the black hole spin-downs via the ``magnetic braking''.Comment: 42 pages, 3 figures, Mon. Not. R. Astron. Soc.(MNRAS), in pres

The Effects Of Natural Disasters On Long-Run Economic Growth

Honors (Bachelor's)EconomicsUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/79459/1/chulkyu.pd

PRIMARY PRODUCTION OF PHYTOPLANKTON AND MACROPHYTES IN AN EUTROPHIC LAGOON, LAKE KYUNGPO, KOREA

Primary production of phytoplankton and macrophytes are measured in a eutrophic lagoon, Lake Kyungpo, where 86% of the lake is inhabited by macrophytes. Phytoplankton standing crop was high, 40-130 mgChl/m³, but productivity per unit area was suppressed low by the light deficiency due to high content of inorganic suspended particles. Contribution of phytoplankton and macrophytes to the total annual production was 55% and 45%, respectively. Allochthonous organic input estimated from BOD was 36% of total organic matter supply. Nitrogen seems to be the limiting nutrient for phytoplankton, since nitrate is often depleted in the water column of macrophyte-growing region and N/P ratio is low. Turbulence and the vertical transfer of oxygen and nutrient are strongly suppressed by the dense population of macrophytes and the chemocline of high stability caused by saline bottom water.Article信州大学理学部付属諏訪臨湖実験所報告 7: 99-103(1991)departmental bulletin pape

A Hybrid Approach Based on Variational Mode Decomposition for Analyzing and Predicting Urban Travel Speed

Predicting travel speeds on urban road networks is a challenging subject due to its uncertainty stemming from travel demand, geometric condition, traffic signals, and other exogenous factors. This uncertainty appears as nonlinearity, nonstationarity, and volatility in traffic data, and it also creates a spatiotemporal heterogeneity of link travel speed by interacting with neighbor links. In this study, we propose a hybrid model using variational mode decomposition (VMD) to investigate and mitigate the uncertainty of urban travel speeds. The VMD allows the travel speed data to be divided into orthogonal and oscillatory sub-signals, called modes. The regular components are extracted as the low-frequency modes, and the irregular components presenting uncertainty are transformed into a combination of modes, which is more predictable than the original uncertainty. For the prediction, the VMD decomposes the travel speed data into modes, and these modes are predicted and summed to represent the predicted travel speed. The evaluation results on urban road networks show that, the proposed hybrid model outperforms the benchmark models both in the congested and in the overall conditions. The improvement in performance increases significantly over specific link-days, which generally are hard to predict. To explain the significant variance of the prediction performance according to each link and each day, the correlation analysis between the properties of modes and the performance of the model are conducted. The results on correlation analysis show that the more variance of nondaily pattern is explained through the modes, the easier it was to predict the speed. Based on the results, discussions on the interpretation on the correlation analysis and future research are presented. Document type: Articl

EUTROPHICATION OF THE MAJOR RESERVOIRS IN KOREA

Trophic state of several major reservoirs in Korea are reviewed. Most of large reservoirs are mesotrophic to eutrophic, suffering bluegreen algal blooms. Recently many reservoirs are being eutrophied at high rate mainly due to the increase of excretion by livestock in watershed and netcage-type fishfarms within the lake basins. The trophic state changes of Lake Soyang, from oligotrophy to eutrophy in recent 10 years, are presented as a case study of rapid eutrophication. Chlorophyll a concentration increased from ca. 3mg/m³ in early 1980s to 15 mg/m³ in 1989. The dominant phytoplankton species in summer are changed from Peridinium to Anabaena since 1986 and the standing crop of Anabaena has been increasing. Secchidisc depth decreased from 5 to 1m. TP increased from 7 to 20 mgP/m³. The rate of hypolimnetic oxygen deficit increased year to year from 0.028 mgO₂/cm²/day in 1986 to 0.094 in 1989. Fishfarms within the lake are the major phosphorus source in Lake Soyang exceeding the total phosphorus loading from the watershed. This high rate of eutrophication is expected to persist in next decade.Article信州大学理学部付属諏訪臨湖実験所報告 7: 21-29(1991)departmental bulletin pape

Dihydrotestosterone-Inducible IL-6 Inhibits Elongation of Human Hair Shafts by Suppressing Matrix Cell Proliferation and Promotes Regression of Hair Follicles in Mice

Autocrine and paracrine factors are produced by balding dermal papilla (DP) cells following dihydrotestosterone (DHT)-driven alterations and are believed to be key factors involved in male pattern baldness. Herein we report that the IL-6 is upregulated in balding DP cells compared with non-balding DP cells. IL-6 was upregulated 3hours after 10–100nM DHT treatment, and ELISA showed that IL-6 was secreted from balding DP cells in response to DHT. IL-6 receptor (IL-6R) and glycoprotein 130 (gp130) were expressed in follicular keratinocytes, including matrix cells. Recombinant human IL-6 (rhIL-6) inhibited hair shaft elongation and suppressed proliferation of matrix cells in cultured human hair follicles. Moreover, rhIL-6 injection into the hypodermis of mice during anagen caused premature onset of catagen. Taken together, our data strongly suggest that DHT-inducible IL-6 inhibits hair growth as a paracrine mediator from the DP