Shock melt vein as alternative plaeomagnetic recorder against chondrules: the case study for chondrite and eucrite

第3回極域科学シンポジウム/第32回極域地学シンポジウム 11月29日（木） 統計数理研究所 ３階セミナー

Vertical intrusive magnetite-series granodiorite as a source of surface magnetic anomalies in the King George Island, Antarctica

第3回極域科学シンポジウム/第32回極域地学シンポジウム 11月29日（木） 国立極地研究所 ３階ラウン

An Experimental Verification of the Design Margin Analysis Method for Even-Stage Ring Oscillators with CMOS Latch

2011 International Conference on Solid State Devices and Materials (SSDM 2011), September 28-30, 2011, Nagoya, Japa

Nonlinear thermoremanence corrections for Thellier paleointensity experiments on single plagioclase crystals with exsolved magnetites: A case study for the Cretaceous Normal Superchron

金沢大学理工研究域地球社会基盤学系Single plagioclase paleointensity experiment has been an excellent tool to reliably estimate ancient geomagnetic field intensity. Although transparent plagioclases with magmatic nanophase magnetites have shown their potential for paleointensity estimation, in most cloudy plagioclases with exsolved magnetites, the problems of strong anisotropy as rod-shape magnetites, the hyperbolic tangential saturation of thermoremanence (TRM), and slow cooling of host plutons need to be addressed. In this paper, we propose experimental schemes to address these problems with considerations of error estimation and uncertainty for paleointensity experiments on exsolved magnetite. First, in order to experimentally check the effect of the hyperbolic tangential saturation of TRM, we performed Thellier simulation experiments using laboratory total TRM as simulated natural remanence (NRM). Single cloudy plagioclases were sampled from early Cretaceous granite in the Kitakami massif, Northeast Japan. We designed the experiment where the total TRM and the partial TRMs in the Thellier experiments were acquired under different field intensities. For these experiments, correction for hyperbolic tangential TRM acquisition yielded precise field intensity estimations. Next, Thellier experiments on NRM of the crystals from the same granite were performed as a demonstration of correction schemes for both magnetic anisotropy and hyperbolic tangential TRM acquisition. Precise determination of anisotropy tensor seems to be the major challenge for single plagioclase paleointensity estimation with exsolved magnetite. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Science

Repeated Pancreatectomy for Recurrent Pancreatic Carcinoma after Pylorus-Preserving Pancreatoduodenectomy: Report of Two Patients

Repeated pancreatectomy for pancreatic carcinoma is extremely rare. We report two such patients who underwent pancreatectomy for carcinoma developing in the pancreatic remnant after pylorus-preserving pancreatoduodenectomy (PpPD) for invasive pancreatic ductal carcinoma. One patient underwent PpPD for invasive pancreatic ductal carcinoma and received adjuvant chemotherapy. Follow-up computed tomography (CT) demonstrated a low-density mass in the remnant pancreas, which was diagnosed as a carcinoma by endoscopic ultrasound-guided fine-needle aspiration cytology 5 years 10 months after PpPD. She underwent curative resection of the remnant pancreas and is alive and well 13 months after the second operation. The other patient underwent PpPD for invasive pancreatic ductal carcinoma. Follow-up CT showed a low-density mass in the remnant pancreas after 2 years 11 months. He received systemic chemotherapy with S-1 for 3 months. The tumor shrank, and the patient underwent curative resection of the remnant pancreas 3 years 1 month after the initial operation. Repeated pancreatectomy may provide a chance of long survival for patients with carcinoma developing in the remnant pancreas after pancreatectomy if the recurrence occurring at long term is limited to the remnant pancreas

Magnetite microexsolutions in silicate and magmatic flow fabric of the Goyozan granitoid (NE Japan): Significance of partial remanence anisotropy

金沢大学理工研究域地球社会基盤学系Anisotropy of magnetic susceptibility (AMS) has been widely used to infer magmatic flow patterns of granitoids where an appropriate AMS axis is parallel to an alignment of mafic minerals or magnetite. The magmatic flow fabric in Cretaceous granitic plutons from northeastern Japan was verified using an analysis of anisotropy of partial anhysteretic remanent magnetization (ApARM) which further isolates the magnetite subfabrics according to magnetite grain size. The preferred orientation of polysynthetic twins in plagioclase laths and clinopyroxene is discordant with the bulk AMS fabric along outer marginal zones of the granitoid, as shown by image analysis of microphotographs from thin sections cut in orthogonal planes. This suggests that the uncorroborated use of bulk AMS to detect flow fabric in granitoids has risks. Scanning electron microscopy (SEM) reveals that submicroscopic, needle-shaped magnetite inclusions exsolved in anhedral plagioclase and clinopyroxene may explain such anomalous exceptions to the validity of AMS fabrics. Our ApARM measurements show that the ApARM alignment of relatively high-coercive, submicroscopic magnetite inclusions is concordant to the linear orientation of anhedral plagioclase and clinopyroxene. The combination of SEM, AMS, and ApARM was required to confirm the magmatic and submagmatic flow pattern of granitoids in this study and is generally preferable to the use of AMS alone. Copyright 2006 by the American Geophysical Union