2,407 research outputs found

    Very high-energy gamma-ray signature of ultrahigh-energy cosmic-ray acceleration in Centaurus A

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    The association of at least a dozen ultrahigh-energy cosmic-ray (UHECR) events with energy 55\gtrsim 55 EeV detected by the Pierre Auger Observatory (PAO) from the direction of Centaurus-A, the nearest radio galaxy, supports the scenario of UHECR acceleration in the jets of radio galaxies. In this work, we model radio to very high energy (VHE,100\gtrsim 100 \rm GeV) γ\gamma-ray emission from Cen A, including GeV hardness detected by Fermi-LAT and TeV emission detected by HESS. We consider two scenarios: (i) Two zone synchrotron self-Compton (SSC) and external-Compton (EC) models, (ii) Two zone SSC, EC and photo-hadronic emission from cosmic ray interactions. The GeV hardness observed by Fermi-LAT can be explained using these two scenarios, where zone 2 EC emission is very important. Hadronic emission in scenario (ii) can explain VHE data with the same spectral slope as obtained through fitting UHECRs from Cen A. The peak luminosity in cosmic ray proton at 1 TeV, to explain the VHE γ\gamma-ray data is 2.5×1046\approx 2.5 \times 10^{46} erg/s. The bolometric luminosity in cosmic ray protons is consistent with the luminosity required to explain the origin of 13 UHECR signal events that are correlated with Cen A.Comment: 6 pages, 3 figures, Accepted for publication in MNRASL, Comments welcom

    Third-party effects of water trading and potential policy responses

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    A key feature of water policy reform in Australia has been the separation of water access entitlements from land titles and the establishment of markets for water. However, the separation of water entitlements from land failed to account for a number of characteristics that were implicit in the joint right. This has given rise to a number of third-party effects as water is traded in an incomplete market. This paper describes four third-party effects of water trade; reliability of supply, timeliness of delivery, storage and delivery charges, and water quality and examines policy responses to address these effects. The discussion draws on the concepts of exclusiveness and rivalry to determine the applicability of property rights and other solutions to the third-party effects of trade. It is likely that many of the third-party effects of trade discussed in this paper do not warrant policy intervention at the national or state level, but intervention at the local level may be warranted. The costs of addressing some third-party effects may outweigh the benefits. Where there are significant gains from trade, the existence of these third-party effects should not been seen as a reason to impede trade.property rights, water trading, third-party effects, Resource /Energy Economics and Policy,

    The Power of Random Symmetry-Breaking in Nakamoto Consensus

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    Linking Forests and Economic Well-being: A Four Quadrant Approach

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    This paper has three main objectives: (1) to investigate whether the four-quadrant approach introduced by Maini (2003) reveals a useful typology for grouping countries by GDP and forest cover per capita, (2) to determine if the framework can enhance our understanding of the relationship between forest cover and GDP per capita, and (3) to investigate why countries in the four-quadrant world occupy different quadrants, and to determine the principal factors affecting country-movement across and within the individual quadrants. The examination reveals that countries can be classified into four broad categories, and that GDP and forest cover per capita have a low but consistent level of negative association. After regressing economic, institutional, social capital and other variables on a country’s occupancy and movement in the four-quadrant world, the results suggest that countries in each quadrant share different characteristics and that factors underlying country-movement varies according to the quadrant being observed. Overall, countries with less corruption and higher education are likely to experience increases in both forest cover and GDP per capita, while countries exporting a significant proportion of forest products have a reduced probability of increasing both variables.Economic well-being, forest cover, institutions, corruption, education

    Analisis Nilai Pengalaman Berbelanja Online Melalui Experiential Marketing

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    Kondisi ekonomi global Dunia sedang mengalami penurunan. Penurunan kondisi global tidak membawa Perubahan besar bagi Indonesia. BPS menyatakan bahwa perekonomian Indonesia tumbuh dan akan terus meningkat selama Tahun 2012. Perkembangan kondisi global Indonesia ini mengakibatkan negara-negara maju mulai tertarik untuk melakukan investasi di Indonesia. Alasannya ialah pertumbuhan ekonomi yang baik dan lanskap penggunaan internet di Indonesia sedang mengalami perkembangan yang baik, sehingga mengembangkan dan menginvestasikan dana yang dimiliki akan memungkinkan pertumbuhan ekonomi negaranya menjadi lebih baik. Meningkatnya penggunaan internet membuat Perubahan besar, banyak industri offline mulai beralih ke online. Ini menimbulkan permasalahan tersendiri bagi situs-situs perdagangan yang ada. Situs yang sedang berkembang adalah Tokobagus dan Tokopedia. Salah satu upaya yang dilakukan untuk menciptakan keputusan pembelian adalah dengan memberikan penawaran terbaik bagi konsumen dengan memberikan pengalaman yang unik dan berkesan. Pengalaman pelanggan dapat diciptakan dengan experiential marketing. Schmitt(1999) mengemukakan bahwa experiential marketing akan bisa menciptakan experience. Experience yang positif akan mampu menciptakan keputusan pembelian. Responden dalampenelitian ini adalah pembeli di situs Tokobagus dan Tokopedia. Metode yang digunakan adalah explanatory survey dan deskriftif survey. Hipotesis dari penelitian ini adalah terdapat pengaruh positif antara penciptaan nilai pengalaman berbelanja online melalui experiential marketing terhadap keputusan pembelian, Untuk mengukur pengaruh variabel tersebut digunakan metode partial least square. Dari hasil penelitian experiential marketing yang dilaksanakan melalui dimensi sense, feel, think, actdan relate memiliki pengaruh yang positif untuk menciptakan nilai pelanggan dan signifikan terhadap keputusan pembelian. Hal yang perlu ditingkatkan Tokobagus dan Tokopedia yaitu dengan memperbaiki design dan tampilan situs supaya lebih menarik perhatian, sehingga bisa merangsang emosi seseorang dan menimbulkan keinginan untuk membeli produk. Tampilan sebaiknya di design dengan unik agar mampu dengan mudah di ingat pembeli

    theoretical and experimental results for Co-OEP on Ni(100)

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    Metal octaethylporphyrins (M-OEP), M-N4C20H4(C2H5)8, adsorbed at a metallic substrate are promising candidates to provide spin dependent electric transport. Despite these systems having been studied extensively by experiment, details of the adsorbate geometry and surface binding are still unclear. We have carried out density functional theory calculations for cobalt octaethyl porphyrin (Co-OEP) adsorbate at clean and oxygen-covered Ni(100) surfaces as well as for the free Co-OEP molecule where equilibrium structures were obtained by corresponding energy optimizations. These geometries were then used in calculations of Co-OEP carbon and nitrogen 1s core excitations yielding theoretical excitation spectra to be compared with corresponding K-edge x-ray absorption fine structure (NEXAFS) measurements. The experimental NEXAFS spectra near the carbon K-edge of Co-OEP bulk material show large intensity close to the ionization threshold and a triple-peak structure at lower energies, which can be reproduced by the calculations on free Co-OEP. The experimental nitrogen K-edge spectra of adsorbed Co-OEP layers exhibit always a double-peak structure below ionization threshold, independent of the layer thickness. The peaks are shifted slightly and their separation varies with adsorbate-substrate distance. This can be explained by hybridization of N 2p with corresponding 3d contributions of the Ni substrate in the excited final state orbitals as a result of adsorbate-substrate binding via N–Ni bond formation

    Bonded Cumomer Analysis of Human Melanoma Metabolism Monitored by 13C NMR Spectroscopy of Perfused Tumor Cells.

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    A network model for the determination of tumor metabolic fluxes from (13)C NMR kinetic isotopomer data has been developed and validated with perfused human DB-1 melanoma cells carrying the BRAF V600E mutation, which promotes oxidative metabolism. The model generated in the bonded cumomer formalism describes key pathways of tumor intermediary metabolism and yields dynamic curves for positional isotopic enrichment and spin-spin multiplets. Cells attached to microcarrier beads were perfused with 26 mm [1,6-(13)C2]glucose under normoxic conditions at 37 °C and monitored by (13)C NMR spectroscopy. Excellent agreement between model-predicted and experimentally measured values of the rates of oxygen and glucose consumption, lactate production, and glutamate pool size validated the model. ATP production by glycolytic and oxidative metabolism were compared under hyperglycemic normoxic conditions; 51% of the energy came from oxidative phosphorylation and 49% came from glycolysis. Even though the rate of glutamine uptake was ∼50% of the tricarboxylic acid cycle flux, the rate of ATP production from glutamine was essentially zero (no glutaminolysis). De novo fatty acid production was ∼6% of the tricarboxylic acid cycle flux. The oxidative pentose phosphate pathway flux was 3.6% of glycolysis, and three non-oxidative pentose phosphate pathway exchange fluxes were calculated. Mass spectrometry was then used to compare fluxes through various pathways under hyperglycemic (26 mm) and euglycemic (5 mm) conditions. Under euglycemic conditions glutamine uptake doubled, but ATP production from glutamine did not significantly change. A new parameter measuring the Warburg effect (the ratio of lactate production flux to pyruvate influx through the mitochondrial pyruvate carrier) was calculated to be 21, close to upper limit of oxidative metabolism

    Karakteristik Intensitas Radioaktivitas Batuan Dan Sedimen Terpilih Di Pantai Sedau, Kalimantan Barat

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    Intensitas pancaran unsur radioaktif berdasarkan data aktivitas batuan dan aktivitas pancaran ß serbuk di Pantai Sedau dilakukan menggunakan metode analisis Spektrometer Gamma dan alat cacah ß terhadap sembilan contoh sedimen dan batuan. Intensitas radioaktif batuan memperlihatkan kisaran U238 dari 0,1202 ± 0,008 Bq/25gr hingga 0,4348 ± 0,005 Bq/25gr; Th232 0,0768 ± 0,005 Bq/25gr hingga 0,4812 ± 0,015 Bq/25gr; sedangkan intensitas gross gammanya berkisar dari 1,0503 ± 0,029 Bq/25gr hingga 5,6433 ± 0,273 Bq/25gr. Semua contoh yang memiliki intensitas unsur radioaktif untuk aktivitas batuan tinggi berasal dari batuan yang sama (monzogranit), yaitu di lokasi SKP08-04. Hasil yang sama pada pancaran ß serbuknya yang memperlihatkan aktivitas ß gross tertinggi juga terjadi di lokasi SKP08-04 pada batuan monzogranit dengan intensitas paparan 0,370 ± 0,025 Bq/25gr. Berdasarkan pengamatan petrografi, monzogranit di SKP08-04 memperlihatkan pelimpahan feldspar dengan kondisi yang relatif belum teralterasi sedangkan berdasarkan analisis geokimia memperlihatkan afinitas berupa seri kalk-alkali yang tinggi potasium. The intensity of the radioactive elements based on the rock activity data and ß powder emission activity on Sedau Coast were done using Gamma Spectrometer analysis method and ß detector to the nine samples of sediment and rocks. Radioactive intensity of U238 in rocks showed a range from 0.1202 ± 0.008 Bq/ 25gr to 0.4348 ± 0.005 Bq/ 25gr; Th232 0.0768 ± 0.005 Bq/ 25gr to 0.4812 ± 0.015 Bq/ 25gr; while the gross gamma intensity ranged from 1.0503 ± 0.029 Bq/ 25gr to 5.6433 ± 0.273 Bq/25gr. All the sample that has high intensity of radioactive element, occurs in the same rock (monzogranite) which is from samples in location SKP08-04. The same results in the emission of ß powder, which showed the highest gross ß activity also occurs in the rocks monzogranite (SKP08-04) with exposure intensity was 0.370 ± 0.025 Bq/25gr. Based on petrographic observations, monzogranite in SKP08-04 showed the presence of abundant feldspar with the condition which relatively not altered, whereas the affinity based on geochemical analysis showed a calc-alkaline series of high potassium
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