Extragalactic Background Light and Gamma-Ray Attenuation

Data from (non-) attenuation of gamma rays from active galactic nuclei (AGN) and gamma ray bursts (GRBs) give upper limits on the extragalactic background light (EBL) from the UV to the mid-IR that are only a little above the lower limits from observed galaxies. These upper limits now rule out some EBL models and purported observations, with improved data likely to provide even stronger constraints. We present EBL calculations both based on multiwavelength observations of thousands of galaxies and also based on semi-analytic models, and show that they are consistent with these lower limits from observed galaxies and with the gamma-ray upper limit constraints. Such comparisons "close the loop" on cosmological galaxy formation models, since they account for all the light, including that from galaxies too faint to see. We compare our results with those of other recent works, and discuss the implications of these new EBL calculations for gamma ray attenuation. Catching a few GRBs with groundbased atmospheric Cherenkov Telescope (ACT) arrays or water Cherenkov detectors could provide important new constraints on the high-redshift star formation history of the universe.Comment: 12 pages, 8 multi-panel figures, Invited talk at the 25th Texas Symposium on Relativistic Astrophysics, Heidelberg December 6-10, 201

Catching GRBs with atmospheric Cherenkov telescopes

Fermi has shown GRBs to be a source of >10 GeV photons. We present an estimate of the detection rate of GRBs with a next generation Cherenkov telescope. Our predictions are based on the observed properties of GRBs detected by Fermi, combined with the spectral properties and redshift determinations for the bursts population by instruments operating at lower energies. While detection of VHE emission from GRBs has eluded ground-based instruments thus far, our results suggest that ground-based detection may be within reach of the proposed Cherenkov Telescope Array (CTA), albeit with a low rate, 0.25 - 0.5/yr. Such a detection would help constrain the emission mechanism of gamma-ray emission from GRBs. Photons at these energies from distant GRBs are affected by the UV-optical background light, and a ground-based detection could also provide a valuable probe of the Extragalactic Background Light (EBL) in place at high redshift.Comment: 4 pages, 3 figures, to appear in the Proceedings of "Gamma Ray Bursts 2010", held Nov. 1-4, 2010 in Annapolis, M

Pengaruh Komite Audit, Ukuran Perusahaan, Ukuran Kap terhadap Tingkat Keselarasan Laporan Tahunan dengan Rerangka Integrated Reporting

Pengaruh Komite Audit, Ukuran Perusahaan, Ukuran KAP terhadap Tingkat Keselarasan Laporan Tahunan dengan Rerangka Integrated Reporting. Penelitian ini bertujuan untuk mengetahui pengaruh Komite Audit, Ukuran Perusahaan dan Ukuran KAP terhadap Tingkat Keselarasan Laporan Tahunan dengan Rerangka Integrated Reporting (IR). Pemilihan variabel dalam penelitian ini karena penelitian sebelumnya menunjukkan hasil yang inkonsiten. Populasi dalam penelitian ini adalah Perusahaan sektor pertambangan yang terdaftar di BEI periode 2014-2015. Metode pengambilan sampel menggunakan metode purposive sampling sehingga diperoleh sebanyak 64 sampel selama dua tahun pengamatan. Teknik pengumpulan data menggunakan metode dokumentasi. Uji analisis data dalam penelitian ini adalah analisis statistik deskriptif, uji asumsi klasik dan uji hipotesis.Hasil penelitian yang telah dilakukan menunjukkan bahwa Komite Audit, Ukuran Perusahaan dan Ukuran KAP baik secara parsial maupun simultan berpengaruh signifikan terhadap Tingkat Keselarasan Laporan Tahunan dengan Rerangka IR

Perancangan E-scm Pada PT Superpoly Industry

Manufacturing companies always strives to improve performance, namely in production of goods in time, management of material supply to prevent out of stock by exchanging information with suppliers, and on time delivery of goods to distributors to meet customer satisfaction on manufactured products. The purpose of this study is to analyse the supply chain management and to design the electronic supply chain management (e-SCM) on Superpoly Industry Company so it able to give accurate and reliable information also support the better supply chain acitivity for the company. The used research methods are preliminary steps (energize the organization, enterprise vision, supply chain value assessment, opportunity identification, and strategy decision) for the analysis and for the design consist of supply chain management strategic, customer and service management, manufacturing and supply chain planning, supplier relationship management, logistics resource management, and architecting. The conclusion is the e-SCM application will make it easier for the distributor to order merchandise from the company because information channel is open, which is website and information flow between supplier, company, and distribution is getting better

Analisis Perbandingan Kinerja pada Bank Nasional dan Bank Asing dengan Menggunakan Analisis Rasio Keuangan

Bank performance appraisal is based on bank financial report itself. The financial report can be form balance report which give information about the financial position to the outside of bank that can be used of eksternal to assess the level of risk exist in a bank. Based on ownership consist of national bank, mixture bank and foreign bank. These banks has tight compete to show a good performance to the public. This research aimed to analyze the financial performance difference of national bank and foreign bank at the period of 2004 to 2013 with the proxy finance ratio (CAMEL ratio) consist of: Capital, Asset Quality, Management, Earnings, and Liquidity. The population in this research consist of national bank and foreign bank listed on the Indonesia Stock Exchange at the period of 2004 to 2013 which amount 42 banks. Based on purposive sampling techniques, the number of samples that meet the criteria are as many as 10 banks (5 national banks and 5 foreign banks). Analysis technique that use in this research is t-test. As the result the USAge of proxy CAMEL ratio to analyze comparison bank performance give evidence that foreign bank performance is better than national bank performance

Diffuse Extragalactic Background Radiation

Attenuation of high--energy gamma rays by pair--production with UV, optical and IR background photons provides a link between the history of galaxy formation and high--energy astrophysics. We present results from our latest semi-analytic models (SAMs), based upon a $\Lambda$CDM hierarchical structural formation scenario and employing all ingredients thought to be important to galaxy formation and evolution, as well as reprocessing of starlight by dust to mid- and far-IR wavelengths. Our models also use results from recent hydrodynamic galaxy merger simulations. These latest SAMs are successful in reproducing a large variety of observational constraints such as number counts, luminosity and mass functions, and color bimodality. We have created 2 models that bracket the likely ranges of galaxy emissivities, and for each of these we show how the optical depth from pair--production is affected by redshift and gamma-ray energy. We conclude with a discussion of the implications of our work, and how the burgeoning science of gamma-ray astronomy will continue to help constrain cosmology.Comment: 12 pages, 8 figures, to be published in the Proceedings of the 4th Heidelberg International Symposium on High Energy Gamma-Ray Astronomy, held July 2008 in Heidelberg, German

Proses Produksi Alat Angkat Kendaraan Niaga Kapasitas 2 Ton

The object of this study is the production process of the 2 tonnes capacity lifting equipment commercial vehicle with carried out in manufacture laboratory of the University of Sam Ratulangi. The aim of this study is to build the component, measuring the lifter parts' processing time, and analyzing the stages of the process, and calculating the production process of the 2 tonnes capacity lifting equipment produced in manufacture laboratory the University of Sam Ratulangi. The result obtained is a commercial vehicle lifting equipment unit manually operated that can do a car lifting till 2 tonnes maximum empty heavy vehicle. The manufacturing time in every single component is 7,684 seconds with 765 units/year production target