A New Hardware Correlator in Korea: Performance Evaluation using KVN observations

We report results of the performance evaluation of a new hardware correlator in Korea, the Daejeon correlator, developed by the Korea Astronomy and Space Science Institute (KASI) and the National Astronomical Observatory of Japan (NAOJ). We conducted Very Long Baseline Interferometry (VLBI) observations at 22~GHz with the Korean VLBI Network (KVN) in Korea and the VLBI Exploration of Radio Astrometry (VERA) in Japan, and correlated the aquired data with the Daejeon correlator. For evaluating the performance of the new hardware correlator, we compared the correlation outputs from the Daejeon correlator for KVN observations with those from a software correlator, the Distributed FX (DiFX). We investigated the correlated flux densities and brightness distributions of extragalactic compact radio sources. The comparison of the two correlator outputs show that they are consistent with each other within $<8\%$, which is comparable with the amplitude calibration uncertainties of KVN observations at 22~GHz. We also found that the 8\% difference in flux density is caused mainly by (a) the difference in the way of fringe phase tracking between the DiFX software correlator and the Daejeon hardware correlator, and (b) an unusual pattern (a double-layer pattern) of the amplitude correlation output from the Daejeon correlator. The visibility amplitude loss by the double-layer pattern is as small as 3\%. We conclude that the new hardware correlator produces reasonable correlation outputs for continuum observations, which are consistent with the outputs from the DiFX software correlator.Comment: 13 pagee, 9 figures, 3 tables, to appear in JKAS (received February 9, 2015; accepted March 16, 2015

Transcatheter Arterial Embolization Using Ethanol in a Dialysis Patient for Contracting Enlarged Polycystic Kidneys

The mass effect of nephromegaly in patients with autosomal dominant polycystic kidney disease may cause pain and symptoms by compressing the alimentary tract, lungs, and heart. Conventional therapies exist to contract enlarged polycystic kidneys including surgical and interventional procedures. A surgical nephrectomy is often difficult to perform in dialysis patients due to the associated risks related to surgery. In contrast, renal transcatheter arterial embolization (TAE) with metallic coils, which is a less invasive interventional procedure, can also be utilized to contract enlarged kidneys in dialysis patients as an effective treatment. However, metallic coils present the possibility of recanalization and cost issues. Thus, we used ethanol instead of coils in renal TAE to resolve these issues. We report a dialysis patient with enlarged polycystic kidneys and poor oral intake due to abdominal distention that was successfully treated by TAE with absolute ethanol

Successful Chemotherapy Following Autologous Stem Cell Transplantation in Multiple Myeloma and Multi-organ Dysfunction with Infiltration of Eosinophils: A Case Report

Eosinophils are derived from hematopoietic stem cells. Peripheral blood eosinophilia is defined as an absolute eosinophil count of ≥0.5×109/L. Eosinophilia is classified into primary or clonal eosinophilia, secondary eosinophilia, and idiopathic categories including idiopathic hypereosinophilic syndrome. Both hematopoietic and solid neoplasms may be associated with peripheral blood eosinophilia, but multiple myeloma is rarely associated with eosinophilia. We now report the case of a 31-year-old man with multiple myeloma associated with marked eosinophilia who developed multiple organ dysfunction with infiltration of eosinophils. He recovered after treatment with chemotherapy followed by autologous stem cell transplantation

Precessing jet nozzle connecting to a spinning black hole in M87

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from General Relativity. With a baseline of 17 years of observations, there was a shift in the jet's transverse position, possibly arising from an eight to ten-year quasi-periodicity. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years in the position angle variation of the jet. We infer that we are seeing a spinning black hole that induces the Lense-Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation.Comment: 41 pages, 7 figures, 7 table

Fluoroscopic Stent Placement as a Bridge to Surgery for Malignant Colorectal Obstruction: Short- and Long-Term Outcomes

Purpose To assess the outcomes of single-stage surgery following fluoroscopic stent placement for malignant colorectal obstruction. Materials and Methods This retrospective study included 46 patients (28 male and 18 female; mean age, 67.2 years) who had undergone fluoroscopic stent placement followed by laparoscopic resection (n = 31) or open surgery (n = 15) for malignant colorectal obstruction. The surgical outcomes were analyzed and compared. After a mean follow-up of 38.9 months, the recurrence-free and overall survival were estimated, and prognostic factors were evaluated. Results The mean interval between stent placement and surgery was 10.2 days. Primary anastomosis was possible in all patients. The mean postoperative length of hospitalization was 11.0 days. Bowel perforation was detected in six patients (13.0%). During the follow-up, ten patients (21.7%) developed recurrence; these included five of the six patients with bowel perforation. Bowel perforation had a significant effect on recurrence-free survival (p = 0.010). Conclusion Single-stage surgery following fluoroscopic stent placement may be effective for treating malignant colorectal obstruction. Stent-related bowel perforation is a significant predictive factor for tumor recurrence