Skyrme Strings

We construct nontopological string solutions with U(1) Noether charge in the Skyrme model with a pion mass term, and examine their stability by taking linear perturbations. The solution exhibits a critical angular velocity beyond which the configuration energetically prefers to decay by emitting pions. This critical point is observed as a cusp in the relation between energy and charge. We find that the maximum length for the string to be stable is comparable to the size of one skyrmion. Beyond the length, it is unstable to decay. This instability raises the possiblity of dynamical realization of Skyrme strings from monopole strings inside a domain wall.Comment: 7 pages, 3 figures, references adde

Hidup Manusia di Dunia Konvergen ke F (X) = 0

Mathematics is a discipline that all the concepts, principles, theorems, axioms, rules.It can stand alone or can be connected to the field, the other disciplines. Because mathematics is the queen of sciences. Mathematics is not only connected to other disciplines, but also there is a connection with everyday life. Mathematical concepts with everyday life is a human life. Human life on earth is temporary given time only, whether the people life could not be judge by any one. Thus, analogous to the way of life of each human being is considered as the line function and then each man eventually leading to death or converge to zero in a line function of real numbers, if this function is approaching to zero, its means that one day the peoplelife has ended

Kemampuan Mengajukan Masalah Direlasikan dengan Kemampuan Berpikir Logis Matematik

This study presents a mathematical problem posing ability related to the ability to logical thinking mathematically. The ability mathematical problem posing and logical thinking is an essential capability owned and developed by students to deal with advances in science and technology that rapidly. Since both the ability it becomes important, then needed the capability development guidance if it is associated with the other. In this study also present how the rubric assessment mathematical problem posing to related with the ability logical thinking. It is expected to be a stimulus to develop mathematical problem posing capability optimally. Keyword: Mathematical problem posing, logical thinking

Coronal propagation of solar flare particles observed by satellite

Propagation of solar flare particles in corona was studied using the satellite data at the geostationary orbit. by selecting very fast rise time events only, the interplanetary propagation were assumed to be scatter free arrival. The results show that the propagation in corona does not depend on particle energy in 4 to 500 MeV protons, and the time delays from optical flare do not depend on the distance between the flare site and the base of the interplanetary magnetic field which connects to the Earth

Shock Formation Height in the Solar Corona Estimated from SDO and Radio Observations

Wave transients at EUV wavelengths and type II radio bursts are good indicators of shock formation in the solar corona. We use recent EUV wave observations from SDO and combine them with metric type II radio data to estimate the height in the corona where the shocks form. We compare the results with those obtained from other methods. We also estimate the shock formation heights independently using white-light observations of coronal mass ejections that ultimately drive the shocks

Cool White Dwarfs Found in the UKIRT Infrared Deep Sky Survey

We present the results of a search for cool white dwarfs in the United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). The UKIDSS LAS photometry was paired with the Sloan Digital Sky Survey (SDSS) to identify cool hydrogen-rich white dwarf candidates by their neutral optical colors and blue near-infrared colors, as well as faint Reduced Proper Motion magnitudes. Optical spectroscopy was obtained at Gemini Observatory, and showed the majority of the candidates to be newly identified cool degenerates, with a small number of G- to K-type (sub)dwarf contaminants. Our initial search of 280 deg2 of sky resulted in seven new white dwarfs with effective temperature T_eff ~ 6000 K. The current followup of 1400 deg2 of sky has produced thirteen new white dwarfs. Model fits to the photometry show that seven of the newly identified white dwarfs have 4120 K <= T_eff <= 4480 K, and cooling ages between 7.3 Gyr and 8.7 Gyr; they have 40 km/s <= v_tan <= 85 km/s and are likely to be thick disk 10-11 Gyr-old objects. The other half of the sample has 4610 K <= T_eff <= 5260 K, cooling ages between 4.3 Gyr and 6.9 Gyr, and 60 km/s <= v_tan <= 100 km/s. These are either thin disk remnants with unusually high velocities, or lower-mass remnants of thick disk or halo late-F or G stars.Comment: To appear in ApJ, accepted April 18 2011. 34 pages include 11 Figures and 5 Table

Exact ground states and domain walls in one dimensional chiral magnets

We determine exactly the phase structure of a chiral magnet in one spatial dimension with the Dzyaloshinskii-Moriya (DM) interaction and a potential that is a function of the third component of the magnetization vector, n3, with a Zeeman (linear with the coefficient B) term and an anisotropy (quadratic with the coefficient A) term, constrained so that 2A ≤ |B|. For large values of potential parameters A and B, the system is in one of the ferromagnetic phases, whereas it is in the spiral phase for small values. In the spiral phase we find a continuum of spiral solutions, which are one-dimensionally modulated solutions with various periods. The ground state is determined as the spiral solution with the lowest average energy density. As the phase boundary approaches, the period of the lowest energy spiral solution diverges, and the spiral solutions become domain wall solutions with zero energy at the boundary. The energy of the domain wall solutions is positive in the homogeneous phase region, but is negative in the spiral phase region, signaling the instability of the homogeneous (ferromagnetic) state. The order of the phase transition between spiral and homogeneous phases and between polarized (n3 = ±1) and canted (n3 ≠ ±1) ferromagnetic phases is found to be second order

Perbandingan Prestasi Belajar antara Siswa yang Mendapatkan Pembelajaran Matematika Berbasis Karakter dengan Konvensional

In this paper, we compared two models of learning is a model-based learning and conventional teaching character to see how far these two learning models are instrumental in improving both student achievement or change in the character of students. Researchers want to see whether the learning ability of students get the learning model based character better than those getting conventional model?. Methods that researchers use to determine the extent to which the success of student learning and the changing character of both the gain and the character-based models that get a conventional model