27 research outputs found

    Counting function fluctuations and extreme value threshold in multifractal patterns: the case study of an ideal 1/f1/f noise

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    To understand the sample-to-sample fluctuations in disorder-generated multifractal patterns we investigate analytically as well as numerically the statistics of high values of the simplest model - the ideal periodic 1/f1/f Gaussian noise. By employing the thermodynamic formalism we predict the characteristic scale and the precise scaling form of the distribution of number of points above a given level. We demonstrate that the powerlaw forward tail of the probability density, with exponent controlled by the level, results in an important difference between the mean and the typical values of the counting function. This can be further used to determine the typical threshold xmx_m of extreme values in the pattern which turns out to be given by xm(typ)=2clnlnM/lnMx_m^{(typ)}=2-c\ln{\ln{M}}/\ln{M} with c=3/2c=3/2. Such observation provides a rather compelling explanation of the mechanism behind universality of cc. Revealed mechanisms are conjectured to retain their qualitative validity for a broad class of disorder-generated multifractal fields. In particular, we predict that the typical value of the maximum pmaxp_{max} of intensity is to be given by lnpmax=αlnM+32f(α)lnlnM+O(1)-\ln{p_{max}} = \alpha_{-}\ln{M} + \frac{3}{2f'(\alpha_{-})}\ln{\ln{M}} + O(1), where f(α)f(\alpha) is the corresponding singularity spectrum vanishing at α=α>0\alpha=\alpha_{-}>0. For the 1/f1/f noise we also derive exact as well as well-controlled approximate formulas for the mean and the variance of the counting function without recourse to the thermodynamic formalism.Comment: 28 pages; 7 figures, published version with a few misprints corrected, editing done and references adde

    Using [C II] 158 μm Emission from Isolated ISM Phases as a Star Formation Rate Indicator

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    The brightest observed emission line in many star-forming galaxies is the [C II] 158 μm line, making it detectable up to z ~ 7. In order to better understand and quantify the [C II] emission as a tracer of star formation, the theoretical ratio between the [N II] 205 μm emission and the [C II] 158 μm emission has been employed to empirically determine the fraction of [C II] emission that originates from the ionized and neutral phases of the interstellar medium (ISM). Sub-kiloparsec measurements of the [C II] 158 μm and [N II] 205 μm lines in nearby galaxies have recently become available as part of the Key Insights in Nearby Galaxies: a Far Infrared Survey with Herschel (KINGFISH) and Beyond the Peak programs. With the information from these two far-infrared lines along with the multi-wavelength suite of KINGFISH data, a calibration of the [C II] emission line as a star formation rate (SFR) indicator and a better understanding of the [C II] deficit are pursued. [C II] emission is also compared to polycyclic aromatic hydrocarbon (PAH) emission in these regions to compare photoelectric heating from PAH molecules to cooling by [C II] in the neutral and ionized phases of the ISM. We find that the [C II] emission originating in the neutral phase of the ISM does not exhibit a deficit with respect to the infrared luminosity and is therefore preferred over the [C II] emission originating in the ionized phase of the ISM as an SFR indicator for the normal star-forming galaxies included in this sample

    Using [C II] 158 μm Emission from Isolated ISM Phases as a Star Formation Rate Indicator

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    The brightest observed emission line in many star-forming galaxies is the [C II] 158 μm line, making it detectable up to z ~ 7. In order to better understand and quantify the [C II] emission as a tracer of star formation, the theoretical ratio between the [N II] 205 μm emission and the [C II] 158 μm emission has been employed to empirically determine the fraction of [C II] emission that originates from the ionized and neutral phases of the interstellar medium (ISM). Sub-kiloparsec measurements of the [C II] 158 μm and [N II] 205 μm lines in nearby galaxies have recently become available as part of the Key Insights in Nearby Galaxies: a Far Infrared Survey with Herschel (KINGFISH) and Beyond the Peak programs. With the information from these two far-infrared lines along with the multi-wavelength suite of KINGFISH data, a calibration of the [C II] emission line as a star formation rate (SFR) indicator and a better understanding of the [C II] deficit are pursued. [C II] emission is also compared to polycyclic aromatic hydrocarbon (PAH) emission in these regions to compare photoelectric heating from PAH molecules to cooling by [C II] in the neutral and ionized phases of the ISM. We find that the [C II] emission originating in the neutral phase of the ISM does not exhibit a deficit with respect to the infrared luminosity and is therefore preferred over the [C II] emission originating in the ionized phase of the ISM as an SFR indicator for the normal star-forming galaxies included in this sample

    Using [C ii] 158 μm Emission from Isolated ISM Phases as a Star Formation Rate Indicator

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    The brightest observed emission line in many star-forming galaxies is the ?m line, making it detectable up to z;?;7. In order to better understand and quantify the <CDATA<i emission as a tracer of star formation, the theoretical ratio between the ?m emission and the ?m emission has been employed to empirically determine the fraction of <CDATA<i emission that originates from the ionized and neutral phases of the interstellar medium (ISM). Sub-kiloparsec measurements of the ?m and ?m lines in nearby galaxies have recently become available as part of the Key Insights in Nearby Galaxies: a Far Infrared Survey with Herschel (KINGFISH) and Beyond the Peak programs. With the information from these two far-infrared lines along with the multi-wavelength suite of KINGFISH data, a calibration of the <CDATA<i emission line as a star formation rate (SFR) indicator and a better understanding of the <CDATA<i deficit are pursued. <CDATA<i emission is also compared to polycyclic aromatic hydrocarbon (PAH) emission in these regions to compare photoelectric heating from PAH molecules to cooling by <CDATA<i in the neutral and ionized phases of the ISM. We find that the <CDATA<i emission originating in the neutral phase of the ISM does not exhibit a deficit with respect to the infrared luminosity and is therefore preferred over the <CDATA<i emission originating in the ionized phase of the ISM as an SFR indicator for the normal star-forming galaxies included in this sample.NASA Headquarters under the NASA Earth and Space Science Fellowship ProgramNational Aeronautics & Space Administration (NASA) [80NSSC18K1107]; NASANational Aeronautics & Space Administration (NASA) [NNX15AI08H]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

    Corruption, rentier states and economic growth: Where do the GCC Countries stand?

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    Countries with vast natural resources usually display low economic outcomes and corruption is always considered as a main economic hinderer in this regard. We consider in this study the Gulf Cooperation Countries as endowed with huge natural resources while considering the potential role of corruption on their economic growth. We first theoretically discuss both the cursing and the blessing effect of natural resources on countries’ economic outcomes. The empirical analysis employed the panel GMM approach to explore whether and how the investment channel and the political stability channel can contribute to explaining the link between corruption and economic growth. Estimation outcomes show that overall corruption negatively impacts economic growth. Given that usually, corruption occurs through the interaction of the business with the public sector, regulatory authorities, as well as policymakers should spend their efforts to improve the transparency of communication between firms and public entities and officials. The result is expected to reduce their discretionary power, as well as the expected gains from corruption. Overall, these countries need to adopt certain institutional reforms, leading to higher accountability, the strength of property rights, and better bureaucratic quality.N/
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