Early (<<0.3 day) R-band light curve of the optical afterglow of GRB030329

We observed the optical afterglow of the bright gamma-ray burst GRB030329 on the nights of 2003 March 29, using the Kiso observatory (the University of Tokyo) 1.05 m Schmidt telescope. Data were taken from March 29 13:21:26 UT to 17:43:16 (0.072 to 0.253 days after the burst), using an $Rc$-band filter. The obtained $Rc$-band light curve has been fitted successfully by a single power law function with decay index of $0.891\pm0.004$. These results remain unchanged when incorporating two early photometric data points at 0.065 and 0.073 days, reported by Price et al.(2003) using the SSO 40 inch telescope, and further including RTT150 data (Burenin et al. 2003) covering at about 0.3 days. Over the period of 0.065-0.285 days after the burst, any deviation from the power-law decay is smaller than $\pm$0.007 mag. The temporal structure reported by Uemura et al. (2003) does not show up in our $R$-band light curve.Comment: 9 pages, 2 figures, 1 table, accepted for publication in ApJ

Precise Control of Band Filling in NaxCoO2

Electronic properties of the sodium cobaltate NaxCoO2 are systematically studied through a precise control of band filling. Resistivity, magnetic susceptibility and specific heat measurements are carried out on a series of high-quality polycrystalline samples prepared at 200 C with Na content in a wide range of 0.35 =< x =< 0.70. It is found that dramatic changes in electronic properties take place at a critical Na concentration x* that lies between 0.58 and 0.59, which separates a Pauli paramagnetic and a Curie-Weiss metals. It is suggested that at x* the Fermi level touches the bottom of the a1g band at the gamma point, leading to a crucial change in the density of states across x* and the emergence of a small electron pocket around the gamma point for x > x*.Comment: 4 pages, 5 figures, submitted to J. Phys. Soc. Jp

Low energy high angular resolution neutral atom detection by means of micro-shuttering techniques: the BepiColombo SERENA/ELENA sensor

The neutral sensor ELENA (Emitted Low-Energy Neutral Atoms) for the ESA cornerstone BepiColombo mission to Mercury (in the SERENA instrument package) is a new kind of low energetic neutral atoms instrument, mostly devoted to sputtering emission from planetary surfaces, from E ~20 eV up to E~5 keV, within 1-D (2x76 deg). ELENA is a Time-of-Flight (TOF) system, based on oscillating shutter (operated at frequencies up to a 100 kHz) and mechanical gratings: the incoming neutral particles directly impinge upon the entrance with a definite timing (START) and arrive to a STOP detector after a flight path. After a brief dissertation on the achievable scientific objectives, this paper describes the instrument, with the new design techniques approached for the neutral particles identification and the nano-techniques used for designing and manufacturing the nano-structure shuttering core of the ELENA sensor. The expected count-rates, based on the Hermean environment features, are shortly presented and discussed. Such design technologies could be fruitfully exported to different applications for planetary exploration.Comment: 11 page

"Pudding mold" band drives large thermopower in Nax_xCoO2_2

In the present study, we pin down the origin of the coexistence of the large thermopower and the large conductivity in Na$_x$CoO$_2$. It is revealed that not just the density of states (DOS), the effective mass, nor the band width, but the peculiar {\it shape} of the $a_{1g}$ band referred to as the "pudding mold" type, which consists of a dispersive portion and a somewhat flat portion, is playing an important role in this phenomenon. The present study provides a new guiding principle for designing good thermoelectric materials.Comment: 5 page

Validation and study of different parameters in the simulation of diagnostic X-ray spectra using the MCNPX code

In radiology, knowing the X-ray spectrum characteristics makes it possible to estimate the absorbed dose in the patient and to improve image quality. In this study, an X-ray generator was proposed using the MCNPX code and to validate it, the simulated spectrum was compared to the data provided from AAPM Task Group 195, which resulted in a percentage difference of 8.7%. Furthermore, several X-ray spectra were generated and compared to the spectra obtained from commercially available softwares as xpecgen and SpekCalc. The percentage differences were of the order of 13% in comparison with SpekCalc and 8% with xpecgen. The major differences obtained between those spectra were concentrated in the region of characteristic peaks, independently if variations in electron beam energy, target angle or filtration thickness were performed

Conventional and CT angiography in children: dosimetry and dose comparisons

Tremendous advances have been made in imaging in children with both congenital and acquired heart disease. These include technical advances in cardiac catheterization and conventional angiography, especially with advancements in interventional procedures, as well as noninvasive imaging with MR and CT angiography. With rapid advances in multidetector CT (MDCT) technology, most recently 64-detector array systems (64-slice MDCT), have come a number of advantages over MR. However, both conventional and CT angiography impart radiation dose to children. Although the presence of radiation exposure to children has long been recognized, it is apparent that our ability to assess this dose, particularly in light of the rapid advancements, has been limited. Traditional methods of dosimetry for both conventional and CT angiography are somewhat cumbersome or involve a potential for substantial uncertainty. Recent developments in dosimetry, including metal oxide semiconductor field effect transistors (MOSFET) and the availability of anthropomorphic, tissue-equivalent phantoms have provided new opportunities for dosimetric assessments. Recent work with this technology in state-of-the-art cardiac angiography suites as well as with MDCT have offered direct comparisons of doses in infants and children undergoing diagnostic cardiac evaluation. It is with these dose data that assessment of risks, and ultimately the assessment of risk-benefit, can be better achieved

Magnetic Conjugacy of Pc1 Waves and Isolated Proton Precipitation at Subauroral Latitudes: Importance of Ionosphere as Intensity Modulation Region

Pc1 geomagnetic pulsations, equivalent to electromagnetic ion cyclotron waves in the magnetosphere, display a specific amplitude modulation, though the region of the modulation remains an open issue. To classify whether the amplitude modulation has a magnetospheric or ionospheric origin, an isolated proton aurora (IPA), which is a proxy of Pc1 wave-particle interactions, is compared with the associated Pc1 waves for a geomagnetic conjugate pair, Halley Research Base in Antarctica and Nain in Canada. The temporal variation of an IPA shows a higher correlation coefficient (0.88) with Pc1 waves in the same hemisphere than that in the opposite hemisphere. This conjugate observation reveals that the classic cyclotron resonance is insufficient to determine the amplitude modulation. We suggest that direct wave radiation from the ionospheric current by IPA should also contribute to the amplitude modulation

Successful Treatment for Hepatic Encephalopathy Aggravated by Portal Vein Thrombosis with Balloon-Occluded Retrograde Transvenous Obliteration

This report presents the case of a 78-year-old female with hepatic encephalopathy due to an inferior mesenteric venous-inferior vena cava shunt. She developed hepatocellular carcinoma affected by hepatitis C virus-related cirrhosis and underwent posterior sectionectomy. Portal vein thrombosis developed and the portal trunk was narrowed after hepatectomy. Portal vein thrombosis resulted in high portal pressure and increased blood flow in an inferior mesenteric venous-inferior vena cava shunt, and hepatic encephalopathy with hyperammonemia was aggravated. The hepatic encephalopathy aggravated by portal vein thrombosis was successfully treated by balloon-occluded retrograde transvenous obliteration via a right transjugular venous approach without the development of other collateral vessels

Topical Review: Development of overgrown semi-polar GaN for high efficiency green/yellow emission

The most successful example of large lattice-mismatched epitaxial growth of semiconductors is the growth of III-nitrides on sapphire, leading to the award of the Nobel Prize in 2014 and great success in developing InGaN-based blue emitters. However, the majority of achievements in the field of III-nitride optoelectronics are mainly limited to polar GaN grown on c-plane (0001) sapphire. This polar orientation poses a number of fundamental issues, such as reduced quantum efficiency, efficiency droop, green and yellow gap in wavelength coverage, etc. To date, it is still a great challenge to develop longer wavelength devices such as green and yellow emitters. One clear way forward would be to grow III-nitride device structures along a semi-/non-polar direction, in particular, a semi-polar orientation, which potentially leads to both enhanced indium incorporation into GaN and reduced quantum confined Stark effects. This review presents recent progress on developing semi-polar GaN overgrowth technologies on sapphire or Si substrates, the two kinds of major substrates which are cost-effective and thus industry-compatible, and also demonstrates the latest achievements on electrically injected InGaN emitters with long emission wavelengths up to and including amber on overgrown semi-polar GaN. Finally, this review presents a summary and outlook on further developments for semi-polar GaN based optoelectronics

Periprostatic fat measured on computed tomography as a marker for prostate cancer aggressiveness

Contains fulltext : 89797.pdf (publisher's version ) (Closed access)OBJECTIVE: Several reports found that obesity was associated with prostate cancer (PC) aggressiveness among men treated with radical prostatectomy or radiotherapy. Studies concerning this issue have basically relied on body mass index (BMI), as a marker for general obesity. Because visceral fat is the most metabolic active fat, we sought to evaluate if periprostatic fat measured on a computed tomography (CT) is a better marker than BMI to predict PC aggressiveness in a Dutch population who underwent brachytherapy for localized PC. PATIENTS AND METHODS: Of the 902 patients who underwent brachytherapy, 725 CT scans were available. Subcutaneous fat thickness (CFT), periprostatic fat area (cm(2)) and fat-density (%) were determined on the CT scan. Patients were stratified into three groups: 75 percentile of the fat-density. Associations between the three fat-density subgroups and BMI and PC aggressiveness were examined. RESULTS: 237 patients were classified as having normal weight (37.2%), 320 as overweight (50.2%) and 80 as obese (12.6%). There was a strong significant association between BMI and fat-density and CFT. The strongest correlation was seen between BMI and CFT (Pearson r coefficient = 0.71). Logistic regression analysis revealed no statistically significant association between the different fat measurements and the risk of having a high-risk disease. CONCLUSIONS: Periprostatic fat and fat-density as measured with CT were not correlated with PC aggressiveness in patients receiving brachytherapy. However, 31% of the patients with a normal BMI had a fat-density of >75 percentile of the periprostatic fat-density.01 december 201