Evolution of Iron Kα_{\alpha} Line Emission in the Black Hole Candidate GX 339-4

GX 339-4 was regularly monitored with RXTE during a period (in 1999) when its X-ray flux decreased significantly (from 4.2$\times 10^{-10}$ erg cm$^{-2} s^{-1}$ to 7.6$\times 10^{-12}$ erg cm$^{-2}$s$^{-1}$ in the 3--20 keV band), as the source settled into the ``off state''. Our spectral analysis revealed the presence of a prominent iron K$_{\alpha}$ line in the observed spectrum of the source for all observations. The line shows an interesting evolution: it is centered at $\sim$6.4 keV when the measured flux is above 5$\times 10^{-11}$ erg cm$^{-2} s^{-1}$, but is shifted to $\sim$6.7 keV at lower fluxes. The equivalent width of the line appears to increase significantly toward lower fluxes, although it is likely to be sensitive to calibration uncertainties. While the fluorescent emission of neutral or mildly ionized iron atoms in the accretion disk can perhaps account for the 6.4 keV line, as is often invoked for black hole candidates, it seems difficult to understand the 6.7 keV line with this mechanism, because the disk should be less ionized at lower fluxes (unless its density changes drastically). On the other hand, the 6.7 keV line might be due to recombination cascade of hydrogen or helium like iron ions in an optically thin, highly ionized plasma. We discuss the results in the context of proposed accretion models.Comment: 18 pages, 2 figures, accepted for publication in the ApJ in v552n2p May 10, 2001 issu

Scattering of positrons and electrons by alkali atoms

Absolute total scattering cross sections (Q sub T's) were measured for positrons and electrons colliding with sodium, potassium, and rubidium in the 1 to 102 eV range, using the same apparatus and experimental approach (a beam transmission technique) for both projectiles. The present results for positron-sodium and -rubidium collisions represent the first Q sub T measurements reported for these collision systems. Features which distinguish the present comparisons between positron- and electron-alkali atom Q sub T's from those for other atoms and molecules (room-temperature gases) which have been used as targets for positrons and electrons are the proximity of the corresponding positron- and electron-alkali atom Q sub T's over the entire energy range of overlap, with an indication of a merging or near-merging of the corresponding positron and electron Q sub T's near (and above) the relatively low energy of about 40 eV, and a general tendency for the positron-alkali atom Q sub T's to be higher than the corresponding electron values as the projectile energy is decreased below about 40 eV

A novel objective no-reference metric for digital video quality assessment

A novel objective no-reference metric is proposed for video quality assessment of digitally coded videos containing natural scenes. Taking account of the temporal dependency between adjacent images of the videos and characteristics of the human visual system, the spatial distortion of an image is predicted using the differences between the corresponding translational regions of high spatial complexity in two adjacent images, which are weighted according to temporal activities of the video. The overall video quality is measured by pooling the spatial distortions of all images in the video. Experiments using reconstructed video sequences indicate that the objective scores obtained by the proposed metric agree well with the subjective assessment scores

Faktor-Faktor yang Mempengaruhi Tingkat Profitabilitas Bank Pembiayaan Rakyat Syariah (BPRS) di Aceh

Profitabilitas bank merupakan kualitas yang dinilai berdasarkan keadaan dan kemampuan suatu bank dalam menghasilkan laba. Penelitian ini bertujuan untuk menguji faktor-faktor yang mempengaruhi tingkat profitabilitas Bank Pembia yaan Rakyat Syariah (BPRS) di Aceh. Profitabilitas dalam penelitian ini diukur dengan menggunakan dua rasio, yaitu return on asset dan return on equity, dengan menggunakan empat faktor yaitu pembiayaan, dana pihak ketiga, financing to deposit ratio dan non performing financing. Metode yang digunakan dalam penelitian ini adalah metode kuantitatif.Adapun sampel yang digunakan adalah Bank Pembiayaan Rakyat Syariah (BPRS) di Aceh yang berjumlah 10 bank dan dipilih berdasarkan metode purposive sampling dengan 140 data pengamatan.Pengamatan dilakukan dari tahun 2010 sampai dengan kuartal III tahun 2015. Hasil penelitian dapat disimpulkan bahwa secara simultan variabel pembiayaan, dana pihak ketiga, financing to deposit ratio dan non performing financing berpengaruh signifikan terhadap return on asset dan return on equity. Untuk pengujian secara parsial, seluruh variabel independen yaitu pembiayaan, dana pihak ketiga, financing to deposit ratio dan non performing financing berpengaruh signifikan terhadap return on asset. Sedangkan terhadap return on equity, hanya variabel dana pihak ketiga dan financing to deposit ratio yang berpengaruh signifikan. Adapun variabel pembiayaan dan non performing financing tidak berpengaruh signifikan terhadap return on equity

Penggunaan Pita Bilangan untuk Meningkatkan Hasil Belajar Siswa dalam Belajar Matematika di Sekolah Dasar

Penelitian ini bertujuan untuk mengetahui hasil rata-rata siswa setelah guru menggunakan pita bilangan dalam pembelajaran matematika di kelas V Sekolah Dasar Negeri 21 Sungai Pinyuh Kabupaten Pontianak. Metode penelitian yang digunakan adalah metode deskriftif dengan pendekatan kualitatif dengan rancangan penelitian tindakan kelas yang dilaksanakan melalui 2 siklus, masing-masing siklus terdiri dari 1 kali pertemuan. Sedangkan subjek dalam penelitian ini adalah guru dan 16 siswa kelas V. Berdasarkan hasil analisis data yang diperoleh yaitu kemampuan guru dalam menyusun RPP mengalami peningkatan 0,33 kategori mendekati baik, kemampuan guru dalam melaksanakan pembelajaran pembelajaran sebesar 0,37 kategori sangat baik. Dan hasil belajar siswa mengalami peningkatan sebesar 1,5 kategori mendekati baik. Kata Kunci : Penggunaan, pita bilangan hasil belajar, matematika. Abstrac: This study aims to determine the average results of students after teachers using tape numbers in mathematics learning in the fifth grade Elementary School District 21 River Pinyuh Pontianak. The method used is descriptive method with qualitative approach to the design of classroom action research conducted through two cycles, each cycle consisting of 1 meeting. While the subjects in this study were teachers and 16 students of class V. Based on the analysis of data obtained by the ability of the teacher in preparing lesson plans increased 0.33 approached either category, the ability of teachers to implement instructional learning was 0.37, very good category. And student learning outcomes increased by 1.5 category approach either

Complete mitochondrial genome of Prismognathus prossi (Coleoptera: Lucanidae) with phylogenetic implications

The complete mitochondrial genome of a Chinese stag beetle, Prismognathus prossi, was generated using the Illumina next-generation sequencing. The mitogenome sequence is 15,984 bp in length, the nucleotide composition isA 36.6%, C17.5%, T34.3% andG11.6%with theAT-content of 70.9%. The sequence has similar features with other reported insectmitogenomes, consisting of 13 proteincoding genes (PCGs), 22 transferRNAgenes, tworibosomalRNAsand a control region. All of the protein-coding genes start with the typicalATNinitiation codon except for COI. Maximum Likelihood (ML) and Bayesian Inference (BI) indicated that P. prossi share an affinity with Lucanus mazama, Lucanus fortunei and Cyclommatus vitalisi

Energy transfer, pressure tensor and heating of kinetic plasma

Kinetic plasma turbulence cascade spans multiple scales ranging from macroscopic fluid flow to sub-electron scales. Mechanisms that dissipate large scale energy, terminate the inertial range cascade and convert kinetic energy into heat are hotly debated. Here we revisit these puzzles using fully kinetic simulation. By performing scale-dependent spatial filtering on the Vlasov equation, we extract information at prescribed scales and introduce several energy transfer functions. This approach allows highly inhomogeneous energy cascade to be quantified as it proceeds down to kinetic scales. The pressure work, $-\left( \boldsymbol{P} \cdot \nabla \right) \cdot \boldsymbol{u}$, can trigger a channel of the energy conversion between fluid flow and random motions, which is a collision-free generalization of the viscous dissipation in collisional fluid. Both the energy transfer and the pressure work are strongly correlated with velocity gradients.Comment: 28 pages, 10 figure

Symmetries of SU(2) Skyrmion in Hamiltonian and Lagrangian approaches

We apply the Batalin-Fradkin-Tyutin (BFT) method to the SU(2) Skyrmion to study the full symmetry structure of the model at the first class Hamiltonian level. On the other hand, we also analyze the symmetry structure of the action having the WZ term, which corresponds to this Hamiltonian, in the framework of the Lagrangian approach. Furthermore, following the BFV formalism we derive the BRST invariant gauge fixed Lagrangian from the above extended action.Comment: 14 pages, final revised version, to appear in Mod. Phys. Lett.