92 research outputs found
In-situ measurement of the ozone concentration in the Arctic Airborne Measurement Program 2002(AAMP02)
From 5 to 14 March, 2002, the Arctic Airborne Measurement Program 2002(AAMP02) was conducted on a round-trip flight between Nagoya, Japan, and Longyearbyen, Svalbard, via Anchorage and Barrow, U.S.A. and the North Pole using a chartered twin-jet aircraft, the Gulfstream-II(G-II). On board the G-II, in-situ measurements of the ozone concentration were carried out every 12s in order to obtain information on air mass differences and advection. Vertical profiles of the ozone concentration observed over Longyearbyen agreed well with those observed by ozone sonde launched around the same time from Ny-Ålesund, about 100km north of Longyearbyen. The ozone variations observed in the upper troposphere and lower stratosphere showed negative correlation with the CO_2 concentration, suggesting vertical displacements of air masses. However, it was also observed that the ozone concentration fluctuated considerably with little consistency with the meteorological field
Thermoluminescence study of ordinary chondrites by TL spatial distribution readout system
The thermoluminescence (TL) image reading technique by the TL spatial distribution readout system is improved 1) to obtain a quantitative glow curve in any part of the TL image, 2) to get fine structure of a TL image and 3) to heat a sample to a higher temperature. This technique is applied to measure the natural and artificial TL glow curves of chondrules in ordinary chondrites, ALH-77294 (H5) and ALH-77216 (L3.8). The fluctuation in the natural LT/HT (region) ratios (LT(region); photons counted in a low temperature region, HT (region); in a high temperature region) of the equilibrated chondrite ALH-77294 is small though that in the unequilibrated chondrite ALH-77216 is large. The equivalent doses of ALH-77294 and ALH-77216 can be estimated from the correlation between natural LT (region) and artificial LT (region) to be about 240krad and 16krad respectively, and are consistent with isotopic ages
Thermoluminescence characteristics and chemical compositions of mesostases in ordinary chondrites
Induced thermoluminescence (TL) images of ordinary chondrites, ALH-77214 (L3.4-3.5), Y-74191 (L3.6), ALH-77216 (L3.8) and ALH-78043 (L6), were measured by the TL spatial distribution readout system combined with a microscope and TL characteristics [peak temperature and peak width] of mesostases were analyzed. Their chemical compositions were also analyzed by an electron probe X-ray microanalyzer. We found that; (1) The mesostasis was responsible for much of the TL in the ordinary chondrites, (2) A mesostasis of normative anorthite compositions showed low peak temperature (∿90℃) and narrow width (∿65℃), while a mesostasis of normative albite compositions showed high peak temperature (∿125℃) and wide width (∿100℃), (3) A main phosphor in a low petrologic grade chondrite 3.5 was a high albite mesostasis, (4) Some chondrules in the same fragments of the type 3 chondrites showed no or weak TL emission and these mesostases had high normative albite. These facts suggest that in type 3 ordinary chondrites; (1) The post-accretional metamorphism cannot account for the coexistence of high albite mesostases with TL emission and no emission and a high anorthite mesostasis with TL emission, (2) Low petrologic grade chondrites 3.5 have a large population of slowly cooled chondrules
Denoising Cosine Similarity: A Theory-Driven Approach for Efficient Representation Learning
Representation learning has been increasing its impact on the research and
practice of machine learning, since it enables to learn representations that
can apply to various downstream tasks efficiently. However, recent works pay
little attention to the fact that real-world datasets used during the stage of
representation learning are commonly contaminated by noise, which can degrade
the quality of learned representations. This paper tackles the problem to learn
robust representations against noise in a raw dataset. To this end, inspired by
recent works on denoising and the success of the cosine-similarity-based
objective functions in representation learning, we propose the denoising
Cosine-Similarity (dCS) loss. The dCS loss is a modified cosine-similarity loss
and incorporates a denoising property, which is supported by both our
theoretical and empirical findings. To make the dCS loss implementable, we also
construct the estimators of the dCS loss with statistical guarantees. Finally,
we empirically show the efficiency of the dCS loss over the baseline objective
functions in vision and speech domains
Red thermoluminescence of enstatite from the Chainpur meteorite
For most ordinary chondrites feldspar is mainly responsible for thermoluminescence [TL], but in type 3 ordinary chondrites, especially those which are most primitive, other minerals are important. We observed red TL with a ∿660nm spectral peak in an ordinary chondrite, Chainpur (LL3.4). The mineral responsible for the red TL was identified as iron-free enstatite. Spatial distribution of TL and cathodoluminescence [CL] for the same specimen was also investigated, and it was found that the red TL areas corresponded to the high-sensitivity areas of red CL
Thermoluminescence of chondrules in primitive ordinary chondrites,Semarkona and Bishunpur
The spatial distribution of the induced thermoluminescence (TL) and TL glow curves of the primitive ordinary chondrites, Semarkona (LL3.0) and Bishunpur (LL3.1), were investigated over a wide range of wavelengths using a TL spatial distribution readout system. Although bulk samples of Semarkona and Bishunpur have very low TL sensitivity, individual chondrules show a wide variety of induced TL intensity and glow curve shape. Chondrules with anorthite-normative mesostases have especially high induced TL intensity, and their TL is produced at wavelengths >480nm, compared with <480nm for the sensitivity range of the usual TL measuring systems. Some of the metamorphism-dependent TL sensitivity of type 3 ordinary chondrite therefore results in changes in the spectrum of the light produced
Carcinosarcoma of the Sigmoid Colon: Report of a Case
Our case was a 65-year-old male, with the chief complaints of diarrhea and abdominal distention. Three years earlier, the patient had undergone transcatheter arterial embolization and radiofrequency treatment based on a diagnosis of hepatocellular carcinoma due to hepatitis B by another doctor. In October 2007, the patient developed diarrhea and increased abdominal distention. In December, CT examination conducted by the previous doctor revealed a 20-cm tumor within the pelvis. The patient was diagnosed with sigmoid colon cancer based on barium enema examination using gastrografin, and was introduced to our hospital for treatment. He was diagnosed with low-differentiated carcinoma by biopsy of the colon during endoscopy and underwent sigmoidectomy based on a diagnosis of sigmoid colon cancer. The tumor had infiltrated the bladder, and a tumorectomy was conducted through partially combined resection. The tumor was a huge lesion occupying the inside of the lumen, and histopathological findings revealed that the tumor, the main part of which lay beneath the mucous membrane, had a transitional image composed of both spindle-shaped atypical cells and sarcomatoid shape. The result of immunostaining was CK7(+), CK20(-), AFP(-), and the patient was diagnosed as having carcinosarcoma of the colon. Carcinosarcoma of the colon is a malignant tumor with poor prognosis, and the mean survival period in past reports was approximately 6 months. The patient was treated with FOLFIRI+Bevacizumab therapy according to chemotherapy for colon cancer, but he was refractory to the therapy
Entecavir Reduces Hepatocarcinogenesis in Chronic Hepatitis B Patients
Chronic hepatitis B (CHB) leads to cirrhosis and hepatocellular carcinoma (HCC). With a cohort of 1,206 CHB patients who visited Okayama University Hospital and related hospitals in 2011 and 2012, we compared the incidence rates of HCC among the patients grouped by age, hepatitis B virus (HBV) DNA, hepatitis B e antigen (HBeAg), and treatment. HCCs were observed in 115 patients with the median observation period of 1,687 days. Among the HCC patients aged ≥ 35 years, HBV DNA ≥ 4 log copies/mL and positive HBeAg at diagnosis (n=184), the HCC incidence rate was 8.4% at 5 years in the entecavir (ETV)-treated patients, 21.8% in the lamivudine (LVD)-treated patients, and 26.4% among the patients not treated with drugs. The cumulative HCC incidence was significantly reduced in the ETV-treated patients compared to those treated with LVD or not treated (p=0.013). Among the patients aged ≥ 35 years with HBV DNA ≥ 4 log copies/mL and negative HBeAg (n=237), the cumulative HCC incidence was 14.6% in 5 years in ETV group and 13.9% among those not treated with a drug (p>0.05). Only small numbers of HCCs occurred in other patients. In CHB patients aged≥35 years with HBV DNA ≥4 log copies/mL and positive HBeAg, ETV treatment is recommended for the suppression of HCC development
Preliminary report of "Arctic Airborne Measurement Program 2002" (AAMP02)
The Arctic Airborne Measurement Program 2002(AAMP 02) campaign was carried out in March 2002 as one of the sub programs of the project Variations of atmospheric constituents and their climate impact in the Arctic". The main goal of the project was to investigate the transport, transformation and radiative effect of trace gases and aerosols, and their role in the global climate. An instrumented jet plane, Gulfstream II(G-II), was flown from Nagoya, Japan via Barrow, Alaska to Longyearbyen(78°N , 15°E ), Svalbard, crossing the Arctic Ocean in the lower stratospher. Three local flights were made over the Greenland Sea around Svalbard and two profile flights near Barrow. The plane was equipped with CO_2 and ozone analyzers, gas and aerosol sampling systems, aerosol particle counter, nephelometer, absorption photometer, PMS particle probes, sunphotometer, dew point hygrometer and dropsonde system. During the campaign, intensitive surface operations were also conducted at Ny-Ålesund(79°N , 12°E ), Svalbard. Vertical profiles of several trace gases gave information about transport, a new observation by sunphotometer derived an aerosol optical depth in the stratosphere, and another new observation by dropsonde gave information on the polar vortex
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