Orbital Evolution of Planets around Intermediate-Mass Giants

Around low- and intermediate-mass (1.5-3 M_sun) red giants, no planets have been found inside 0.6 AU. Such a paucity is not seen in the case of 1 M_sun main sequence stars. In this study, we examine the possibility that short-period planets were engulfed by their host star evolving off the main sequence. To do so, we have simulated the orbital evolution of planets, including the effects of stellar tide and mass loss, to determine the critical semimajor axis, a_crit, beyond which planets survive the RGB expansion of their host star. We have found that a_crit changes drastically around 2 M_sun: In the lower-mass range, a_crit is more than 1 AU, while a_crit is as small as about 0.2 AU in the higher-mass range. Comparison with measured semimajor axes of known planets suggests that there is a lack of planets that only planet engulfment never accounts for in the higher-mass range. Whether the lack is real affects our understanding of planet formation. Therefore, increasing the number of planet samples around evolved intermediate-mass stars is quite meaningful to confirm robustness of the lack of planets.Comment: 4 pages, 3 figures, Part of PlanetsbeyondMS/2010 proceedings http://arxiv.org/html/1011.660

Fractal analysis for the ULF data during the 1993 Guam earthquake to study prefracture criticality

International audienceAn extremely large earthquake (with magnitude of 8.2) happened on 8 August 1993 near the Guam island, and ultra-low-frequency (ULF) (frequency less than 1 Hz) electromagnetic fields were measured by 3-axis induction magnetometers at an observing station (with the epicentral distance of 65 km) with sampling frequency of 1 Hz. In order to study electromagnetic signature of prefracture criticality, we have undertaken the fractal (mono-fractal) analysis by means of the Higuchi's method for the ULF data during the 1993 Guam earthquake. Then, it is found that the fractal dimension exhibits five maxima 99, 75, 52, 21, and 9?4 days before the earthquake main shock, which suggests the ULF electromagnetic signature of nonlinear evolution (in the sense of self-organized criticality) taking place in the lithosphere just before the 1993 large Guam earthquake. That is, there take place step-like changes in the lithosphere during the long-term of the order of several months before the main shock

Planet Population Synthesis

With the increasing number of exoplanets discovered, statistical properties of the population as a whole become unique constraints on planet formation models provided a link between the description of the detailed processes playing a role in this formation and the observed population can be established. Planet population synthesis provides such a link. The approach allows to study how different physical models of individual processes (e.g., proto-planetary disc structure and evolution, planetesimal formation, gas accretion, migration, etc.) affect the overall properties of the population of emerging planets. By necessity, planet population synthesis relies on simplified descriptions of complex processes. These descriptions can be obtained from more detailed specialised simulations of these processes. The objective of this chapter is twofold: 1) provide an overview of the physics entering in the two main approaches to planet population synthesis and 2) present some of the results achieved as well as illustrate how it can be used to extract constraints on the models and to help interpret observations.Comment: 23 pages, 8 figures, accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Henning. Updated references relative to v

Planet Formation: Statistics of spin rates and obliquities of extrasolar planets

We develop a simple model of planetary formation, focusing our attention on those planets with masses less than 10 Earth masses and studying particularly the primordial spin parameters of planets resulting from the accretion of planetesimals and produced by the collisions between the embryos. As initial conditions, we adopt the oligarchic growth regime of protoplanets in a disc where several embryos are allowed to form. We take different initial planetary system parameters and for each initial condition, we consider an evolution of 20 millon of years of the system. We perform simulations for 1000 different discs, and from their results we derive the statistical properties of the assembled planets. We have taken special attention to the planetary obliquities and rotation periods, such as the information obtained from the mass and semi major axis diagram, which reflects the process of planetary formation. The distribution of obliquities was found to be isotropic, which means that planets can rotate in direct or indirect sense, regardless of their mass. Our results regarding the primordial rotation periods show that they are dependent on the region where the embryo was formed and evolved. According to our results, most of the planets have rotation periods between 10 and 10000 hours and there are also a large population of planets similar to terrestrial planets in the Solar System.Comment: 10 pages, 16 figures, accepted for publication in MNRA

Perancangan Web Perpustakaan pada SMP Taruna Bhakti Depok

The school library is a place that provides textbooks and readings for students and teachers to support the teaching and learning process. The system of borrowing and returning books in libraries still using the manual system is feared that there will be mistakes when recording book lending, the number of books available, the difficulties in finding books and what information books are available. Implementation of web-based libraries is expected to facilitate students / teachers easy to find out what books are available, librarians become more helpful in monitoring the stock of books and the process of borrowing and return of books, so as to be able to solve the problems that are feared occurred

Measurements of poloidal rotation velocity using charge exchange spectroscopy in a large helical device

Absolute measurements of poloidal rotation velocity with the accuracy up to 1 km/s (2 pm in wavelength) were done using charge exchange spectroscopy in a large helical device. Radial profiles of the absolute Doppler shift of charge exchange emission with a beam are obtained from spectra measured with four sets of optical fiber arrays that view downward and upward at the poloidal cross section with and without neutral beam injection. By arranging the optical fiber from four arrays close to each other at the entrance slit, the apparent Doppler shift due to aberrations of the spectrometer and due to interference of the cold component (the charge exchange between He-like oxygen and thermal neutrals 8 pm from the charge exchange emission with a beam) can be eliminated from the measurements. The measured poloidal rotation velocity is 1 3 km/s in the electron diamagnetic direction at half of the plasma minor radius

An attempt at the computer-aided management of HIV infection

AbstractThe immune system is a complex and diverse system in the human body and HIV virus disrupts and destroys it through extremely complicated but surprisingly logical process. The purpose of this paper is to make an attempt to present a method for the computer-aided management of HIV infection process by means of a mathematical model describing the dynamics of the host pathogen interaction with HIV-1. Treatments for the AIDS disease must be changed to more efficient ones in accordance with the disease progression and the status of the immune system. The level of progression and the status are represented by parameters which are governed by our mathematical model. It is then exhibited that our model is numerically stable and uniquely solvable. With this knowledge, our mathematical model for HIV disease progression is formulated and physiological interpretations are provided. The results of our numerical simulations are visualized, and it is seen that our results agree with medical aspects from the point of view of antiretroviral therapy. It is then expected that our approach will take to address practical clinical issues and will be applied to the computer-aided management of antiretroviral therapies

Investigation of transition frequencies of two acoustically coupled bubbles using a direct numerical simulation technique

The theoretical results regarding the ``transition frequencies'' of two acoustically interacting bubbles have been verified numerically. The theory provided by Ida [Phys. Lett. A 297 (2002) 210] predicted the existence of three transition frequencies per bubble, each of which has the phase difference of $\pi /2$ between a bubble's pulsation and the external sound field, while previous theories predicted only two natural frequencies which cause such phase shifts. Namely, two of the three transition frequencies correspond to the natural frequencies, while the remaining does not. In a subsequent paper [M. Ida, Phys. Rev. E 67 (2003) 056617], it was shown theoretically that transition frequencies other than the natural frequencies may cause the sign reversal of the secondary Bjerknes force acting between pulsating bubbles. In the present study, we employ a direct numerical simulation technique that uses the compressible Navier-Stokes equations with a surface-tension term as the governing equations to investigate the transition frequencies of two coupled bubbles by observing their pulsation amplitudes and directions of translational motion, both of which change as the driving frequency changes. The numerical results reproduce the recent theoretical predictions, validating the existence of the transition frequencies not corresponding to the natural frequency.Comment: 18 pages, 8 figures, in pres

Perlindungan Konsumen melalui Kontrol Sosial Formal dan Informal

Upaya pemberdayaan konsumen adalah sangat penting, karena tidak mudah mengharapkan Upaya pemberdayaan konsumen adalah sangat penting, karena tidak mudah mengharapkan kesadaran pelaku usaha yang pada dasarnya prinsip ekonomi pelaku usaha adalah mendapat kesadaran pelaku usaha yang pada dasarnya prinsip ekonomi pelaku usaha adalah mendapat keuntungan yang semaksimal mungkin dengan modal seminimal mungkin. Di sisi lain, kondisi dan keuntungan yang semaksimal mungkin dengan modal seminimal mungkin. Di sisi lain, kondisi dan fenomena tersebut dapat mengakibatkan kedudukan pelaku uasaha dan konsumen menjadi tidak fenomena tersebut dapat mengakibatkan kedudukan pelaku uasaha dan konsumen menjadi tidak seimbang dan konsumen berada pada posisi yang lemah. Untuk meningkatkan harkat dan seimbang dan konsumen berada pada posisi yang lemah. Untuk meningkatkan harkat dan martabat konsumen perlu peningkatan kesadaran, pengetahuan, kepedulian, kemampuan, dan martabat konsumen perlu peningkatan kesadaran, pengetahuan, kepedulian, kemampuan, dan kemandirian konsumen untuk melindungi dirinya serta menumbuh kembangkan sikap pelaku usaha kemandirian konsumen untuk melindungi dirinya serta menumbuh kembangkan sikap pelaku usaha yang bertanggungjawab. Di Indonesia, dengan berlakunya Undang-Undang Perlindungan yang bertanggungjawab. Di Indonesia, dengan berlakunya Undang-Undang Perlindungan Konsumen (UUPK) No 8 Tahun 1999, maka sejak 20 April 2000, baik melalui negosiasi ataupun Konsumen (UUPK) No 8 Tahun 1999, maka sejak 20 April 2000, baik melalui negosiasi ataupun melalui LPSK persoalan pelanggaran konsumen dapat diselesiakan. Oleh karena itu atas dasar melalui LPSK persoalan pelanggaran konsumen dapat diselesiakan. Oleh karena itu atas dasar kondisi tersebut, maka perlu upaya pemberdayaan konsumen melalui undang-undang yang dapat kondisi tersebut, maka perlu upaya pemberdayaan konsumen melalui undang-undang yang dapat melindungi kepentingan konsumen secara integratif dan komprehensif serta dapat diterapkan melindungi kepentingan konsumen secara integratif dan komprehensif serta dapat diterapkan secara efektif di masyarakat sehingga perlindungan terhadap konsumen yaitu masyarakat secara efektif di masyarakat sehingga perlindungan terhadap konsumen yaitu masyarakat Indonesia dapat terwujud. Indonesia dapat terwujud. Key words: perlindungan, konsumen,kontrol sosial Key words: perlindungan, konsumen,kontrol sosia