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

Cu(InGa)Se 2 THIN-FILM SOLAR CELLS: COMPARATIVE LIFE-CYCLE ANALYSIS OF BUFFER LAYERS

ABSTRACT: A motivation for replacing the current CdS buffer layer in CIGS PV is to avoid potential environmental-and human-health risks related to cadmium compounds. However, to gain a full perspective, such risks should be evaluated throughout the entire life cycle of the CdS, and also of alternative buffer layers. Based on data from the National Renewable Energy Laboratory and Global Solar Energy, we examined the life-cycle Cd emissions during materials production and the deposition processes for CdS and ZnS buffers. We found that the Cd emissions from the buffer layers are minimal compared to the upstream emissions from fossil-fuel-based electricity that the electricity generated from CIGS PV will replace. Accordingly, assuring a higher efficiency of CIGS PV is the best strategy to minimize Cd emissions to the environment In addition, the production of ZnS (and InS) entails some Cd emissions as Cd is present in Zn ores. Based on the current efficiencies of alternative cell designs, CIGS/CdS will create a smaller amount of net Cd emissions than the CIGS/ZnS or CIGS/InS-based alternatives

Segmental duodenectomy with duodenojejunostomy of gastrointestinal stromal tumor involving the duodenum

Duodenal gastrointestinal stromal tumors (GISTs) are uncommon and a relatively small subset of GISTs whose optimal surgical procedure has not been well defined. Because submucosal spread and local lymph node involvement is infrequent in GISTs, wide margins with routine lymph node dissection may not be required. Various techniques of limited resection for duodenal GISTs have been described depending on the site and the size of the tumors. In this study, we report two cases of GIST involving the third and fourth portion of the duodenum successfully treated by segmental duodenectomy with end-to-end duodenojejunostomy. This technique should be considered as a treatment option for GIST located at the third and fourth portion of the duodenum

Risk and Reward in Venture Capital Funds

Using detailed data from Korea, free from the selection bias problem and providing industry codes for companies a venture capital (VC) fund invests in, this study conducts comprehensive analyses of performance and performance persistence of VC funds. We find significant differences between the results using a non-risk-adjusted and those using a risk-adjusted performance measure. Another notable finding is that government participation affects the risk-adjusted performance and cash inflows of venture capital funds. Furthermore, the persistence of performance is much weaker when we control risk of VC funds. In addition, we provide the evidence that the performance in a public market has a positive influence on the probability of raising subsequent venture capital funds.This research was supported by Hallym university Research Fund, 2012 (HRF- 201209-014(II))