Constraints on a new alternative model to dark energy

The recent type Ia supernova data suggest that the universe is accelerating now and decelerated in recent past. This may provide the evidence that the standard Friedmann equation needs to be modified. We analyze in detail a new model in the context of modified Friedmann equation using the supernova data published by the High-$z$ Supernova Search Team and the Supernova Cosmology Project. The new model explains recent acceleration and past deceleration. Furthermore, the new model also gives a decelerated universe in the future.Comment: 12 pages, 5 figures, use ws-ijmpd, minor changes made. In the new version, a detailed derivation of the model is give

Parallel symbolic state-space exploration is difficult, but what is the alternative?

State-space exploration is an essential step in many modeling and analysis problems. Its goal is to find the states reachable from the initial state of a discrete-state model described. The state space can used to answer important questions, e.g., "Is there a dead state?" and "Can N become negative?", or as a starting point for sophisticated investigations expressed in temporal logic. Unfortunately, the state space is often so large that ordinary explicit data structures and sequential algorithms cannot cope, prompting the exploration of (1) parallel approaches using multiple processors, from simple workstation networks to shared-memory supercomputers, to satisfy large memory and runtime requirements and (2) symbolic approaches using decision diagrams to encode the large structured sets and relations manipulated during state-space generation. Both approaches have merits and limitations. Parallel explicit state-space generation is challenging, but almost linear speedup can be achieved; however, the analysis is ultimately limited by the memory and processors available. Symbolic methods are a heuristic that can efficiently encode many, but not all, functions over a structured and exponentially large domain; here the pitfalls are subtler: their performance varies widely depending on the class of decision diagram chosen, the state variable order, and obscure algorithmic parameters. As symbolic approaches are often much more efficient than explicit ones for many practical models, we argue for the need to parallelize symbolic state-space generation algorithms, so that we can realize the advantage of both approaches. This is a challenging endeavor, as the most efficient symbolic algorithm, Saturation, is inherently sequential. We conclude by discussing challenges, efforts, and promising directions toward this goal

Origin of Thermal and Non-Thermal Hard X-ray Emission from the Galactic Center

We analyse new results of Chandra and Suzaku which found a flux of hard X-ray emission from the compact region around Sgr A$^\ast$ (r ~ 100 pc). We suppose that this emission is generated by accretion processes onto the central supermassive blackhole when an unbounded part of captured stars obtains an additional momentum. As a result a flux of subrelativistic protons is generated near the Galactic center which heats the background plasma up to temperatures about 6-10 keV and produces by inverse bremsstrahlung a flux of non-thermal X-ray emission in the energy range above 10 keV.Comment: to be published in PASJ, v.61, No.5, 200

Enhancement of deuterated ethane on Jupiter

We report laboratory measurements of cross sections of CH_3D and C_2H_5D in the extreme ultraviolet. The results are incorporated in a photochemical model for the deuterated hydrocarbons up to C_2 in the upper atmosphere of Jupiter, taking into account the fast reactions for exchanging H and D atoms between H_2 and CH_4, H + HD ↔ D + H_2, CH_3 + D ↔ CH_2D + H. Since there is no reliable kinetics measurement for the reaction, CH_2D + H → CH_3 + D, we use Yung et al.'s estimate for its rate constant. The strong temperature dependence for this reaction leads to large isotopic fractionation for CH_3D and C_2H_5D in the upper atmosphere of Jupiter, where their production rates depend on the abundance of deuterated methyl radical. The model predicts that the D/H ratio in deuterated ethane is about 15 times that of the bulk atmosphere. A confirmation of this result would provide a sensitive test of the photochemistry of hydrocarbons in the atmosphere of Jupiter

Noncommutative Quantum Mechanics from Noncommutative Quantum Field Theory

We derive noncommutative multi-particle quantum mechanics from noncommutative quantum field theory in the nonrelativistic limit. Paricles of opposite charges are found to have opposite noncommutativity. As a result, there is no noncommutative correction to the hydrogen atom spectrum at the tree level. We also comment on the obstacles to take noncommutative phenomenology seriously, and propose a way to construct noncommutative SU(5) grand unified theory.Comment: 14 pages, Latex, minor modification, references adde

Sustainabilitas Arsitektur Masjid: Evaluasi Konsep “Simple Architecture” sebagai Implementasi Desain Arsitektur Berkelanjutan suatu Kawasan

Makalah ini membahas aspek-aspek “kesederhanaan” (simplicity) sebagai konsep desain bangunan masjid secara berkelanjutan (sustainable) sesuai konteks dengan mengambil studi kasus masjid kawasan Al-Irsyad Satya Kota Baru Parahyangan, Bandung. Masjid sebagai subyek arsitektur dan pusat ibadah menjadi ruang publik yang didesain dari elemen-elemen yang secara ideal mengandung nilai-nilai Islam dan bertujuan mendukung fungsinya. Desain masjid berkonsep simple atau “sederhana” digunakan sebagai alternatif kontemporer untuk mengoptimalisasi fungsi tersebut, meliputi struktur bangunan hingga biaya pemeliharaan (maintenance) sesuai prinsip keberlanjutan. Keterkaitan erat bangunan masjid dengan aktivitas masyarakat berpotensi melibatkan partisipasi masyarakat dan pengelola dalam menerapkan program sustainabilitas sesuai konteks lingkungannya. Metode yang digunakan dalam penelitian ini berbasis pendekatan Grounded Theory secara kualitatif melalui pengumpulan data dari kegiatan observasi, interview dan analisis program keberlanjutan kawasan. Penelitian menemukan keterkaitan konsep “sederhana” yang mendukung sustainabilitas desain sekaligus menggarisbawahi evaluasi konsep desain “sederhana” yang hadir serta faktor pemeliharaan/pengembangan masjid dan kawasan

Genome maps across 26 human populations reveal population-specific patterns of structural variation.

Large structural variants (SVs) in the human genome are difficult to detect and study by conventional sequencing technologies. With long-range genome analysis platforms, such as optical mapping, one can identify large SVs (>2 kb) across the genome in one experiment. Analyzing optical genome maps of 154 individuals from the 26 populations sequenced in the 1000 Genomes Project, we find that phylogenetic population patterns of large SVs are similar to those of single nucleotide variations in 86% of the human genome, while ~2% of the genome has high structural complexity. We are able to characterize SVs in many intractable regions of the genome, including segmental duplications and subtelomeric, pericentromeric, and acrocentric areas. In addition, we discover ~60 Mb of non-redundant genome content missing in the reference genome sequence assembly. Our results highlight the need for a comprehensive set of alternate haplotypes from different populations to represent SV patterns in the genome

AMiBA Wideband Analog Correlator

A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband IF distribution, backend signal processing and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.Comment: 28 pages, 23 figures, ApJ in press