The Philippines Typhoon Alley: The Historic Bagyos of the Philippines and Their Impact

Setiap tahun Filipina dilanda hampir selusin badai tropis. Badai yang dibarengi turunnya hujan lebat ini menyebabkan kerusakan berat dan merenggut kehidupan warga Filipina. Selama kurun satu tahun, badai tropis ini mengalami proses beberapa tahap di atas permukaan laut sebelum melintasi daratan. Beberapa wilayah di Filipina rentan terhadap badai topis dan taifun ini. Sementara wilayah lain tidak begitu parah terkena dampak dan potensi kerusakannya. Terkait perubahan iklim, badai yang sangat kuat dalam bentuk super taifun menjadi sedikit lumrah. Tulisan ini bertutur tentang bagaimana pembentukan badai tropis yang berlangsung setiap tahunnya di wilayah Pasifik Barat dan dampaknya bagi kehidupan warga. Tulisan ini juga mengaitkan data historis tentang badai ini di Filipina, termasuk badai super Yolanda yang dideskripsikan sebagai badai terkuat pernah melintas di permukaan bumi.Kata kunci: Badai tropis, taifun, rehabilitasi, rekonstruksi

The Philippine View of Indonesian Independence: As Reported in Philippine Newspapers

For the Filipinos, seeing Indonesia become independent was like seeing themselves. Filipinos themselves as inspiring their neighbors and at the same time they saw what their country could be. There are various parallelisms not only on the day Indonesia formally entered the community of nations but also through that nations struggle for freedom and independence. Here the Filipinos can see the various paths they may have taken, an armed struggle or a peaceful political negotiation, or both. Indonesians too saw themselves among the Filipinos. Like many Asians, they observed events from the 19th century to the recognition of Philippine sovereignty by the United States. At the same time, both countries entered a neocolonial period with the Philippines entering various agreements with its former colonizer which tied up its prerogatives. The Hague Agreement tried to impose a neocolonial condition by constructing a Netherlands-Indonesian union similar to that of the British Commonwealth of Nations. At the same time, the Netherlands played an old tactic of divide and rule by setting up what appeared to be puppet governments in the various regions of Indonesia in support for itself and denying Indonesia the western part of New Guinea by alleging that the region was not culturally affiliated with the central and western halves of the archipelago. It was an attempt to retain the Netherlands as an Asian power. Like the Philippines Indonesia faced new challenges after independence and most of these involved its former colonizer

Cosmological Implications of the Fundamental Relations of X-ray Clusters

Based on the two-parameter family nature of X-ray clusters of galaxies obtained in a separate paper, we discuss the formation history of clusters and cosmological parameters of the universe. Utilizing the spherical collapse model of cluster formation, and assuming that the cluster X-ray core radius is proportional to the virial radius at the time of the cluster collapse, the observed relations among the density, radius, and temperature of clusters imply that cluster formation occurs in a wide range of redshift. The observed relations favor the low-density universe. Moreover, we find that the model of $n\sim -1$ is preferable.Comment: 7 pages, 4 figures. To be published in ApJ Letter

Ionization rates in a Bose-Einstein condensate of metastable Helium

We have studied ionizing collisions in a BEC of He*. Measurements of the ion production rate combined with measurements of the density and number of atoms for the same sample allow us to estimate both the 2 and 3-body contributions to this rate. A comparison with the decay of the number of condensed atoms in our magnetic trap, in the presence of an rf-shield, indicates that ionizing collisions are largely or wholly responsible for the loss. Quantum depletion makes a substantial correction to the 3-body rate constant.Comment: 4 pages, 3 figure

Normalizing the Temperature Function of Clusters of Galaxies

We re-examine the constraints which can be robustly obtained from the observed temperature function of X-ray cluster of galaxies. The cluster mass function has been thoroughly studied in simulations and analytically, but a direct simulation of the temperature function is presented here for the first time. Adaptive hydrodynamic simulations using the cosmological Moving Mesh Hydro code of Pen (1997a) are used to calibrate the temperature function for different popular cosmologies. Applying the new normalizations to the present-day cluster abundances, we find $\sigma_8=0.53\pm 0.05 \Omega_0^{-0.45}$ for a hyperbolic universe, and $\sigma_8=0.53\pm 0.05 \Omega_0^{-0.53}$ for a spatially flat universe with a cosmological constant. The simulations followed the gravitational shock heating of the gas and dark matter, and used a crude model for potential energy injection by supernova heating. The error bars are dominated by uncertainties in the heating/cooling models. We present fitting formulae for the mass-temperature conversions and cluster abundances based on these simulations.Comment: 20 pages incl 5 figures, final version for ApJ, corrected open universe \gamma relation, results unchange

Weak Lensing as a Calibrator of the Cluster Mass-Temperature Relation

The abundance of clusters at the present epoch and weak gravitational lensing shear both constrain roughly the same combination of the power spectrum normalization sigma_8 and matter energy density Omega_M. The cluster constraint further depends on the normalization of the mass-temperature relation. Therefore, combining the weak lensing and cluster abundance data can be used to accurately calibrate the mass-temperature relation. We discuss this approach and illustrate it using data from recent surveys.Comment: Matches the version in ApJL. Equation 4 corrected. Improvements in the analysis move the cluster contours in Fig1 slightly upwards. No changes in the conclusion

Mass-Temperature Relation of Galaxy Clusters: A Theoretical Study

Combining conservation of energy throughout nearly-spherical collapse of galaxy clusters with the virial theorem, we derive the mass-temperature relation for X-ray clusters of galaxies $T=CM^{2/3}$. The normalization factor $C$ and the scatter of the relation are determined from first principles with the additional assumption of initial Gaussian random field. We are also able to reproduce the recently observed break in the M-T relation at T \sim 3 \keV, based on the scatter in the underlying density field for a low density $\Lambda$CDM cosmology. Finally, by combining observational data of high redshift clusters with our theoretical formalism, we find a semi-empirical temperature-mass relation which is expected to hold at redshifts up to unity with less than 20% error.Comment: 43 pages, 13 figures, One figure is added and minor changes are made. Accepted for Publication in Ap