1,221 research outputs found

    A Phase Lag between Disk and Corona in GRMHD Simulations of Precessing Tilted Accretion Disks

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    In the course of its evolution, a black hole (BH) accretes gas from a wide range of directions. Given a random accretion event, the typical angular momentum of an accretion disc would be tilted by ∌\sim60∘^\circ relative to the BH spin. Misalignment causes the disc to precess at a rate that increases with BH spin and tilt angle. We present the first general-relativistic magnetohydrodynamic (GRMHD) simulations spanning a full precession period of highly tilted (60∘^\circ), moderately thin (h/r=0.1h/r=0.1) accretion discs around a rapidly spinning (a≃0.9a\simeq0.9) BH. While the disc and jets precess in phase, we find that the corona, sandwiched between the two, lags behind by ≳10∘\gtrsim 10^{\circ}. For spectral models of BH accretion, the implication is that hard non-thermal (corona) emission lags behind the softer (disc) emission, thus potentially explaining some properties of the hard energy lags seen in Type-C low frequency quasi-periodic oscillations in X-Ray binaries. While strong jets are unaffected by this disc-corona lag, weak jets stall when encountering the lagging corona at distances r∌100r \sim 100 black hole radii. This interaction may quench large-scale jet formation.Comment: 5 pages, 4 figures, submitted to MNRAS, see YouTube playlist for 3D renderings: https://www.youtube.com/playlist?list=PLDO1oeU33GwmwOV_Hp9s7572JdU8JPSS

    Modal Sosial sebagai Strategi Kelangsungan Hidup Perempuan Pekerja Seks (Studi Wilayah Transaksi Seksual Teluk Bintuni, Papua Barat dan Pasar Kembang, Kota YOGYAKARTA)

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    Penelitian ini dilakukan di wilayah transaksi seksual Distrik Bintuni dan Pasar Kembang. Setiap wilayah transaksi seksual, diambil sampel 30 pekerja seks dengan menggunakan metode simple random sampling dan indepth interview. Tujuan dari penelitian ini adalah 1) mengetahui karakteristik wilayah transaksi seksual dan profil perempuan pekerja seks di Teluk Bintuni-Papua Barat dan Pasar Kembang, Kota Yogyakarta, 2) menganalisis bentuk-bentuk pemanfaatan modal sosial sebagai upaya strategi kelangsungan hidup para pekerja seks di wilayah transaksi seksual. Hasil penelitian menunjukkan bahwa karakteristik pekerja seks di Bintuni memiliki mobilitas yang tinggi dengan usia yang relatif muda dan memiliki karakteristik wilayah transaksi seksual yang menyebar dan tersisip, sedangkan di Pasar Kembang para pekerja seks cenderung menetap, memiliki usia relatif tua dan terletak secara mengelompok

    A novel distributed architecture for IoT image processing using low-cost devices and open internet standards

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    Industry 4.0 can be defined as the integration of computers and automation to current industrial processes, with addition of smart and autonomous systems leveraged by machine learning techniques. In this scenario, a compact, dependable and fast controller is desired, featuring low energy consumption, easily programming and maintenance, with no mobile parts. Nowadays, computing power in single board computers, e.g. the Raspberry Pi among others, has been increased at a very important rate. In just three generations, Pi computers offer almost a two-fold speed gain, when compared to first models. Its design, an underlying video driver with general capabilities of regular OSes, makes them quite suitable to build image processing systems at very low cost, with no mobile parts and low energy consumption. However, designing such a system for industrial image processing is a tough challenge, since it implies to integrate cameras, image processing libraries, database servers and application software with graphical user interface, in an already resource constrained device. This work presents a new architecture for this kind of systems, by means of open internet standards, using a self-contained, high performance web server to publish a RESTful API and a set of web pages that use latest HTML5 capabilities to manage USB webcams and system data. This proposal also integrates OpenCV as a compiled script on client-side using the new WASM paradigm, with an optimized storage for images using -industry-standard RDBMS and a modular design that can target Windows and Linux as well.Sociedad Argentina de InformĂĄtica e InvestigaciĂłn Operativ

    Long term effectiveness of the mixture of diatomaceous earth and deltamethrin on wheat

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    A mixture of diatomaceous earth (DE) and deltamethrin (DM) was developed to control stored-grain insect pests. The formulation contains a low quantity of DE and small amounts of insecticide deltamethrin technical powder dissolved in solvent and soap. This study was initiated in order to determine how long the mixture DE/DM will provide acceptable protection against infestation by the rice weevil, Sitophilus oryzae (L.), the lesser grain borer Rhyzopertha dominica (F.) and the red flour beetle, Tribolium castaneum (Herbst), when applied to hard red spring wheat (HRSW) and stored under normal storage conditions. Immediately after treatment, all three species were controlled at 100 milligram per kg or parts per million (ppm) of DE/DM mixture. At 100 ppm, DE/DM mixture provided 100% population reduction of all three species for up to 12 months with little or no progeny produced.Keywords: Diatomaceous earth, Deltamethrin, Mixture, Wheat, Protectio

    Creating Composite Indicators with DEA and Robustness Analysis: the case of the Technology Achievement Index

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    Composite indicators are regularly used for benchmarking countries’ performance, but equally often stir controversies about the unavoidable subjectivity that is connected with their construction. Data Envelopment Analysis helps to overcome some key limitations, viz., the undesirable dependence of final results from the preliminary normalization of sub-indicators, and, more cogently, from the subjective nature of the weights used for aggregating. Still, subjective decisions remain, and such modelling uncertainty propagates onto countries’ composite indicator values and relative rankings. Uncertainty and sensitivity analysis are therefore needed to assess robustness of final results and to analyze how much each individual source of uncertainty contributes to the output variance. The current paper reports on these issues, using the Technology Achievement Index as an illustration.factor is more important in explaining the observed progress.composite indicators, aggregation, weighting, Internal Market

    Creating composite indicators with DEA and robustness analysis: The case of the technology achievement index.

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    Composite indicators are regularly used for benchmarking countries’ performance, but equally often stir controversies about the unavoidable subjectivity that is connected with their construction. Data Envelopment Analysis helps to overcome some key limitations, viz., the undesirable dependence of final results from the preliminary normalization of sub-indicators, and, more cogently, from the subjective nature of the weights used for aggregating. Still, subjective decisions remain, and such modelling uncertainty propagates onto countries’ composite indicator values and relative rankings. Uncertainty and sensitivity analysis are therefore needed to assess robustness of final results and to analyze how much each individual source of uncertainty contributes to the output variance. The current paper reports on these issues, using the Technology Achievement Index as an illustration.Indexes; Indicators; Robustness; Technology;
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