Quantum Creation of the Randall-Sundrum Bubble

We investigate the semiclassical instability of the Randall-Sundrum brane world. We carefully analyze the bubble solution with the Randall-Sundrum background, which expresses the decay of the brane world. We evaluate the decay probability following the Euclidean path integral approach to quantum gravity. Since a bubble rapidly expands after the nucleation, the entire spacetime will be occupied by such bubbles.Comment: 13 pages, 6 figures, To appear in Prog. Theor. Phy

Toward a Deterministic Model of Planetary Formation VII: Eccentricity Distribution of Gas Giants

The ubiquity of planets and diversity of planetary systems reveal planet formation encompass many complex and competing processes. In this series of papers, we develop and upgrade a population synthesis model as a tool to identify the dominant physical effects and to calibrate the range of physical conditions. Recent planet searches leads to the discovery of many multiple-planet systems. Any theoretical models of their origins must take into account dynamical interaction between emerging protoplanets. Here, we introduce a prescription to approximate the close encounters between multiple planets. We apply this method to simulate the growth, migration, and dynamical interaction of planetary systems. Our models show that in relatively massive disks, several gas giants and rocky/icy planets emerge, migrate, and undergo dynamical instability. Secular perturbation between planets leads to orbital crossings, eccentricity excitation, and planetary ejection. In disks with modest masses, two or less gas giants form with multiple super-Earths. Orbital stability in these systems is generally maintained and they retain the kinematic structure after gas in their natal disks is depleted. These results reproduce the observed planetary mass-eccentricity and semimajor axis-eccentricity correlations. They also suggest that emerging gas giants can scatter residual cores to the outer disk regions. Subsequent in situ gas accretion onto these cores can lead to the formation of distant (> 30AU) gas giants with nearly circular orbits.Comment: 54 pages, 14 Figures; accepted for publication in Astrophysical Journa

Lifting of D1-D5-P states

We consider states of the D1-D5 CFT where only the left-moving sector is excited. As we deform away from the orbifold point, some of these states will remain BPS while others can `lift'. We compute this lifting for a particular family of D1-D5-P states, at second order in the deformation off the orbifold point. We note that the maximally twisted sector of the CFT is special: the covering surface appearing in the correlator can only be genus one while for other sectors there is always a genus zero contribution. We use the results to argue that fuzzball configurations should be studied for the full class including both extremal and near-extremal states; many extremal configurations may be best seen as special limits of near extremal configurations.Comment: 51 pages, 6 figure

Psychophysical and physiological evidence for fast binaural processing

The mammalian auditory system is the temporally most precise sensory modality: To localize low-frequency sounds in space, the binaural system can resolve time differences between the ears with microsecond precision. In contrast, the binaural system appears sluggish in tracking changing interaural time differences as they arise from a low-frequency sound source moving along the horizontal plane. For a combined psychophysical and electrophysiological approach, we created a binaural stimulus, called "Phasewarp," that can transmit rapid changes in interaural timing. Using this stimulus, the binaural performance in humans is significantly better than reported previously and comparable with the monaural performance revealed with amplitude-modulated stimuli. Parallel, electrophysiological recordings of binaural brainstem neurons in the gerbil show fast temporal processing of monaural and different types of binaural modulations. In a refined electrophysiological approach that was matched to the psychophysics, the seemingly faster binaural processing of the Phasewarp was confirmed. The current data provide both psychophysical and physiological evidence against a general, hard-wired binaural sluggishness and reconcile previous contradictions of electrophysiological and psychophysical estimates of temporal binaural performance

Eccentricity Evolution of Extrasolar Multiple Planetary Systems due to the Depletion of Nascent Protostellar Disks

Most extrasolar planets are observed to have eccentricities much larger than those in the solar system. Some of these planets have sibling planets, with comparable masses, orbiting around the same host stars. In these multiple planetary systems, eccentricity is modulated by the planets' mutual secular interaction as a consequence of angular momentum exchange between them. For mature planets, the eigenfrequencies of this modulation are determined by their mass and semi-major axis ratios. But, prior to the disk depletion, self gravity of the planets' nascent disks dominates the precession eigenfrequencies. We examine here the initial evolution of young planets' eccentricity due to the apsidal libration or circulation induced by both the secular interaction between them and the self gravity of their nascent disks. We show that as the latter effect declines adiabatically with disk depletion, the modulation amplitude of the planets' relative phase of periapse is approximately invariant despite the time-asymmetrical exchange of angular momentum between planets. However, as the young planets' orbits pass through a state of secular resonance, their mean eccentricities undergo systematic quantitative changes. For applications, we analyze the eccentricity evolution of planets around Upsilon Andromedae and HD168443 during the epoch of protostellar disk depletion. We find that the disk depletion can change the planets' eccentricity ratio. However, the relatively large amplitude of the planets' eccentricity cannot be excited if all the planets had small initial eccentricities.Comment: 50 pages including 11 figures, submitted to Ap

Faktor yang Berhubungan dengan Tindakan Merokok pada Mahasiswa Universitas Hasanuddin Makassar

Konsumsi rokok di Indonesia merupakan konsumsi rokok tertinggi ke lima di dunia. Secara nasional prevalensi penduduk umur di atas 15 tahun di Indonesia yang merokok setiap hari sebesar 28,2%. Merokok di kalangan remaja bisa merupakan bentuk tindakan awal dari penyalahgunaan narkoba, 90% pecandu narkoba bermula dari perokok pada usia muda. Penelitian bertujuan mengetahui faktor yang berhubungan dengan tindakan merokok pada mahasiswa Universitas Hasanuddin, Makassar. Jenis penelitian adalah penelitian analitik observasional dengan desain cross sectional study. Populasi adalah seluruh mahasiswa laki-laki dan perempuan pada Universitas Hasanuddin sebanyak 21.927orang. Sampel dalam penelitian ini adalah mahasiswa yang terpilih sebanyak 378 orang. Pengambilan sampel dengan cara proporsional stratified random sampling. Hasil penelitian menunjukkan responden yang masih merokok sebanyak 91 orang (24,1%). Hasil uji chi square menunjukkan semua variabel memiliki hubungan dengan tindakan merokok, yaitu pengetahuan (p=0,000, φ=0,232), sikap (p=0,000, φ=0,396), kemudahan mengakses rokok (p=0,000, φ=0,264), dukungan keluarga (p=0,044, φ=0,104), dukungan teman sebaya (p=0,000, φ=0,605), dan promosi/iklan rokok (p=0,000, φ=0,366).Kesimpulannya adalah faktor pengetahuan, sikap, kemudahan mengakses rokok, dukungan keluarga, dukungan teman sebaya, promosi/iklan memiliki hubungan dengan tindakan merokok