Thermal-gravitational wind equation for the wind-induced gravitational signature of giant gaseous planets: mathematical derivation, numerical method, and illustrative solutions

© 2015. The American Astronomical Society. All rights reserved. Received 26 February 2015, accepted for publication 4 May 2015 Published 23 June 2015Please cite the published version available at DOI: 10.1088/0004-637X/806/2/270The standard thermal wind equation (TWE) relating the vertical shear of a flow to the horizontal density gradient in an atmosphere has been used to calculate the external gravitational signature produced by zonal winds in the interiors of giant gaseous planets. We show, however, that in this application the TWE needs to be generalized to account for an associated gravitational perturbation. We refer to the generalized equation as the thermalgravitational wind equation (TGWE). The generalized equation represents a two-dimensional kernel integral equation with the Green’s function in its integrand and is hence much more difficult to solve than the standard TWE. We develop an extended spectral method for solving the TGWE in spherical geometry. We then apply the method to a generic gaseous Jupiter-like object with idealized zonal winds. We demonstrate that solutions of the TGWE are substantially different from those of the standard TWE. We conclude that the TGWE must be used to estimate the gravitational signature of zonal winds in giant gaseous planets

Local helioseismology and correlation tracking analysis of surface structures in realistic simulations of solar convection

We apply time-distance helioseismology, local correlation tracking and Fourier spatial-temporal filtering methods to realistic supergranule scale simulations of solar convection and compare the results with high-resolution observations from the SOHO Michelson Doppler Imager (MDI). Our objective is to investigate the surface and sub-surface convective structures and test helioseismic measurements. The size and grid of the computational domain are sufficient to resolve various convective scales from granulation to supergranulation. The spatial velocity spectrum is approximately a power law for scales larger than granules, with a continuous decrease in velocity amplitude with increasing size. Aside from granulation no special scales exist, although a small enhancement in power at supergranulation scales can be seen. We calculate the time-distance diagram for f- and p-modes and show that it is consistent with the SOHO/MDI observations. From the simulation data we calculate travel time maps for surface gravity waves (f-mode). We also apply correlation tracking to the simulated vertical velocity in the photosphere to calculate the corresponding horizontal flows. We compare both of these to the actual large-scale (filtered) simulation velocities. All three methods reveal similar large scale convective patterns and provide an initial test of time-distance methods.Comment: 15 pages, 9 figures (.ps format); accepted to ApJ (tentatively scheduled to appear in March 10, 2007 n2 issue); included files ms.bbl, aabib.bst, aabib.sty, aastex.cl

Substrate specificity and complex stability of coproporphyrin ferrochelatase is governed by hydrogen‐bonding interactions of the four propionate groups

Coproporpyhrin III is the substrate of coproporphyrin ferrochelatases (CpfCs). These enzymes catalyse the insertion of ferrous iron into the porphyrin ring. This is the penultimate step within the coproporphyrin‐dependent haeme biosynthesis pathway. This pathway was discovered in 2015 and is mainly utilised by monoderm bacteria. Prior to this discovery, monoderm bacteria were believed to utilise the protoporphyrin‐dependent pathway, analogously to diderm bacteria, where the substrate for the respective ferrochelatase is protoporphyrin IX, which has two propionate groups at positions 6 and 7 and two vinyl groups at positions 2 and 4. In this work, we describe for the first time the interactions of the four‐propionate substrate, coproporphyrin III, and the four‐propionate product, iron coproporphyrin III (coproheme), with the CpfC from Listeria monocytogenes and pin down differences with respect to the protoporphyrin IX and haeme b complexes in the wild‐type (WT) enzyme. We further created seven LmCpfC variants aiming at altering substrate and product coordination. The WT enzyme and all the variants were comparatively studied by spectroscopic, thermodynamic and kinetic means to investigate in detail the H‐bonding interactions, which govern complex stability and substrate specificity. We identified a tyrosine residue (Y124 in LmCpfC), coordinating the propionate at position 2, which is conserved in monoderm CpfCs, to be highly important for binding and stabilisation. Importantly, we also describe a tyrosine‐serine‐threonine triad, which coordinates the propionate at position 4. The study of the triad variants indicates structural differences between the coproporphyrin III and the coproheme complexes.Enzyme EC 4.99.1.

EUSO science

EUSO is a mission to explore the extreme universe by the probe of Ultra High Energy Cosmic Rays (UHECRs) and UHE neutrinos. EUSO monitors a gigantic volume of atmosphere from Space and measures showers induced by UHECRs and UHE neutrinos. Scientifically, it is important to measure the energy spectrum of UHECRs well beyond GZK energy with high statistics. EUSO ensures the observation of UHECRs up to 10$^{21}$eV even in the case of GZK mechanism working, and gives us a clear picture of the existence / non-existence of the GZK effect and the behavior of the spectrum beyond GZK energy, which represents the contributions from nearby sources. The anisotropy study of UHECR arrival directions in a small scale angle above GZK energy may allow us to identify individual source, because of the limited propagation distance and the high rigidity of particles. If event clusters observed by AGASA are real, it is expected from Monte Carlo simulation that EUSO will see ~100 particles from individual brightest sources and will give us a good opportunity to test the relativity in high precision. The UHE neutrino is a unique channel to explore the universe much deeper than UHECRs. EUSO essentially can measure UHE neutrinos free from background proton showers. The number of GZK neutrino events in a EUSO three years' mission is expected to be only a few. Nevertheless, it is a definitely conceivable opportunity to begin UHE neutrino astrophysics at GZK energy

Evaluation of doctors’ performance as facilitators in basic medical science lecture classes in a new Malaysian medical school

Background: Didactic lecture is the oldest and most commonly used method of teaching. In addition, it is considered one of the most efficient ways to disseminate theories, ideas, and facts. Many critics feel that lectures are an obsolete method to use when students need to perform hands-on activities, which is an everyday need in the study of medicine. This study evaluates students’ perceptions regarding lecture quality in a new medical school. Methods: This was a cross-sectional study conducted of the medical students of Universiti Sultan Zainal Abidin. The study population was 468 preclinical medical students from years 1 and 2 of academic year 2012–2013. Data were collected using a validated instrument. There were six different sections of questions using a 5-point Likert scale. The data were then compiled and analyzed, using SPSS version 20. Results: The response rate was 73%. Among 341 respondents, 30% were male and 70% were female. Eighty-five percent of respondents agree or strongly agree that the lectures had met the criteria with regard to organization of lecture materials. Similarly, 97% of students agree or strongly agree that lecturers maintained adequate voices and gestures. Conclusion: Medical students are quite satisfied with the lecture classes and the lectures. However, further research is required to identify student-centered teaching and learning methods to promote active learning

Notes on the Potential for the Concentration of Rare Earth Elements and Yttrium in Coal Combustion Fly Ash

Certain Central Appalachian coals, most notably the Fire Clay coal with a REY-enriched volcanic ash fall tonstein, are known to be enriched in rare earth elements. The Fire Clay tonstein has a greater contribution to the total coal + parting REY than would be inferred from its thickness, accounting for about 20%–35% of the REY in the coal + parting sequence. Underground mining, in particular, might include roof and floor rock and the within-seam partings in the mined product. Beneficiation, necessary to meet utility specifications, will remove some of the REY from the delivered product. In at least one previously published example, even though the tonstein was not present in the Fire Clay coal, the coal was enriched in REY. In this case, as well as mines that ship run-of-mine products to the utility, the shipped REY content should be virtually the same as for the mined coal. At the power plant, however, the delivered coal will be pulverized, generally accompanied by the elimination of some of the harder rock, before it is fired into the boiler. Overall, there are a wide range of variables between the geologic sample at the mine and the power plant, any or all of which could impact the concentration of REY or other critical materials in the coal combustion products

Active control of magnetoresistance of organic spin valves using ferroelectricity

Organic spintronic devices have been appealing because of the long spin life time of the charge carriers in the organic materials and their low cost, flexibility and chemical diversity. In previous studies, the control of resistance of organic spin valves is generally achieved by the alignment of the magnetization directions of the two ferromagnetic electrodes, generating magnetoresistance.1 Here we employ a new knob to tune the resistance of organic spin valves by adding a thin ferroelectric interfacial layer between the ferromagnetic electrode and the organic spacer. We show that the resistance can be controlled by not only the spin alignment of the two ferromagnetic electrodes, but also by the electric polarization of the interfacial ferroelectric layer: the MR of the spin valve depends strongly on the history of the bias voltage which is correlated with the polarization of the ferroelectric layer; the MR even changes sign when the electric polarization of the ferroelectric layer is reversed. This new tunability can be understood in terms of the change of relative energy level alignment between ferromagnetic electrode and the organic spacer caused by the electric dipole moment of the ferroelectric layer. These findings enable active control of resistance using both electric and magnetic fields, opening up possibility for multi-state organic spin valves and shed light on the mechanism of the spin transport in organic spin valves

FINE NEEDLE ASPIRATION CYTOLOGY OF BREAST LUMP IN T.U. TEACHING HOSPITAL

This is a retrospective study of fine needle aspiration cytology of breast lesions performed between May 1998 and April 2000. During this period, a total of 2001 fine needle aspirations were done in the Tribhuvan Universtiy Teaching Hospital (TUTH), of which 470 (23.48 %) were of the breast. Fibrocystic disease found to be the most frequent and was diagnosed in 183 cases (38.9%). Fibroadenoma was the third common pathological condition, numbering 61 (12.9%). Malignant conditions of the breast were 72 cases (15.3%). During these two years, histological diagnosis was available in 154 cases. Histological examination revealed benign conditions in 74 cases (48%), malignancy in 59 cases (38.3%) and inflammatory & lactational changes in 21 cases (13.7%). Out of these 154 cases, 71 cases had also undergone fine needle aspiration cytology. The 36 cases diagnosed as benign cytologically, 34 cases were also benign histologically, whereas 2 cases turned out to be malignant. Out of 37 cases that were histologically malignant, on cytology 35 cases were diagnosed as malignant. The sensitivity and specificity of cytopathological diagnosis for breast lesions was 100% and 94.6% respectively. Inflammatory lesions correlated well cytologically and histolgically. FNAC is a safe and rapid diagnostic method for evaluation of various lesions. However, there are possibilities of false negative and false positive results because of wide range of appearance of breast lesions. Key Words: Breast lumps, Fine Needle Aspiration Cytology, Benign Lesions, Malignant Lesions, Histopathology and Correlation

Prospects for terahertz imaging the human skin cancer with the help of gold-nanoparticles-based terahertz-to-infrared converter

The design is suggested, and possible operation parameters are discussed, of an instrument to inspect a skin cancer tumour in the terahertz (THz) range, transferring the image into the infrared (IR) and making it visible with the help of standard IR camera. The central element of the device is the THz-to-IR converter, a Teflon or silicon film matrix with embedded 8.5 nm diameter gold nanoparticles. The use of external THz source for irradiating the biological tissue sample is presumed. The converter's temporal characteristics enable its performance in a real-time scale. The details of design suited for the operation in transmission mode (in vitro) or on the human skin in reflection mode {in vivo) are specified.Comment: To be published in the proceedings of the FANEM2018 workshop - Minsk, 3-5 June 201

High Altitude test of RPCs for the ARGO-YBJ experiment

A 50 m**2 RPC carpet was operated at the YangBaJing Cosmic Ray Laboratory (Tibet) located 4300 m a.s.l. The performance of RPCs in detecting Extensive Air Showers was studied. Efficiency and time resolution measurements at the pressure and temperature conditions typical of high mountain laboratories, are reported.Comment: 16 pages, 10 figures, submitted to Nucl. Instr. Met