On Period and Burst Histories of AXPs and SGRs and the Possible Evolution of these Objects on the P-Pdot Diagram

In this paper, timing data for all of the anomalous X-ray pulsars and soft gamma repeaters are compiled. Timing properties of these objects are investigated. The effect of bursts of soft gamma repeaters on their period history is investigated. The P-Pdot diagram for pulsars, X-ray binaries, anomalous X-ray pulsars, soft gamma repeaters and dim radio quiet netron stars is constructed. The possible evolutionary tracks for anomalous X-ray pulsars, soft gamma repeaters and dim radio quiet netron stars are examined.Comment: 66 pages, 9 figures, submitted to Turkish Journal of Physic

Beras Dan Jebakan Kepentingan Jangka Pendek

Kebijakan tentang perberasan sangat sarat dengan berbagai kepentingan, sehingga banyak keputusan yang diambil oleh pemerintah cenderung mengarah pada kepentingan jangka pendek, seperti masalah harga pembelian pemerintah, impor dan kebijakan jangka pendek lainnya. Kalau diperhatikan secara seksama ada empat persoalan mendasar dalam masalah perberasan, yaitu : (1) lemahnya akurasi data; (2) miskinnya petani padi; (3) besarnya ketergantungan terhadap beras; dan (4) masalah harga serta distribusi beras. Agar persoalan ini dapat diselesaikan dengan baik, diperlukan adanya pemetaan persoalan secara tepat dalam berbagai perspektif waktu, dan kemudian merumuskan berbagai langkah operasional yang sistematis dan komprehensif. Hal yang utama diperlukan adalah kejelasan target akhir yang ingin dicapai, yang didasarkan pada proyeksi terhadap kebutuhan beras dan ketersediaan lahan dalam jangka panjang. Upaya ini diharapkan dapat mencegah terjadinya pengulangan program yang sama dari waktu ke waktu, tanpa kejelasan sasaran akhir yang ingin dicapai. Proses akumulasi serta sinergi yang saling memperkuat antar semua pemangku kepentingan terkait, merupakan kata kunci keberhasilan dalam menuntaskan masalah ini

First Dark Matter Results from the XENON100 Experiment

The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso in Italy, is designed to search for dark matter WIMPs scattering off 62 kg of liquid xenon in an ultra-low background dual-phase time projection chamber. In this letter, we present first dark matter results from the analysis of 11.17 live days of non-blind data, acquired in October and November 2009. In the selected fiducial target of 40 kg, and within the pre-defined signal region, we observe no events and hence exclude spin-independent WIMP-nucleon elastic scattering cross-sections above 3.4 x 10^-44 cm^2 for 55 GeV/c^2 WIMPs at 90% confidence level. Below 20 GeV/c^2, this result constrains the interpretation of the CoGeNT and DAMA signals as being due to spin-independent, elastic, light mass WIMP interactions.Comment: 5 pages, 5 figures. Matches published versio

Material screening and selection for XENON100

Results of the extensive radioactivity screening campaign to identify materials for the construction of XENON100 are reported. This Dark Matter search experiment is operated underground at Laboratori Nazionali del Gran Sasso (LNGS), Italy. Several ultra sensitive High Purity Germanium detectors (HPGe) have been used for gamma ray spectrometry. Mass spectrometry has been applied for a few low mass plastic samples. Detailed tables with the radioactive contaminations of all screened samples are presented, together with the implications for XENON100.Comment: 8 pages, 1 figur

Dark Matter Results from 100 Live Days of XENON100 Data

We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows to select only the innermost 48 kg as ultra-low background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in a pre-defined signal region with an expected background of 1.8 +/- 0.6 events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic WIMP-nucleon scattering cross-sections above 7.0x10^-45 cm^2 for a WIMP mass of 50 GeV/c^2 at 90% confidence level.Comment: 5 pages, 5 figures; matches accepted versio