After over 60 years, the powerful engines that accelerate ultra-high-energy cosmic rays (UHECRs) to the formidable energies at which we observe them from Earth remain mysterious. Assuming standard ...physics, we expect UHECR sources to lie within the local Universe (up to a few hundred Mpc). The distribution of matter in the local Universe is anisotropic, and we expect this anisotropy to be imprinted on the distribution of UHECR arrival directions. Even though intervening intergalactic and Galactic magnetic fields deflect charged UHECRs and can distort these anisotropies, some amount of information on the distribution of the sources is preserved. In this proceedings contribution, we present the results of the joint Pierre Auger Observatory and Telescope Array searches for (a) the largest-scale anisotropies (the harmonic dipole and quadrupole) and (b) correlations with a sample of nearby starburst galaxies and the 2MRS catalogue tracing stellar mass within 250 Mpc. This analysis updates our previous results with the most recent available data, notably with the addition of 3 years of new Telescope Array data. The main finding is a correlation between the arrival directions of 12.1%
−3.1%
+4.5%
of UHECRs detected with
E ≥
38 EeV by Auger or with
E ≳
49 EeV by TA and the positions of nearby starburst galaxies on a 15.1°
−3.0°
+4.6°
angular scale, with a 4.7σ post-trial significance, up from 4.2σ obtained in our previous study.
The present white paper is submitted as part of the “Snowmass” process to help inform the long-term plans of the United States Department of Energy and the National Science Foundation for high-energy ...physics. It summarizes the science questions driving the Ultra-High-Energy Cosmic-Ray (UHECR) community and provides recommendations on the strategy to answer them in the next two decades.
The origin of ultra-high-energy cosmic rays (UHECRs) is still unknown. Their sources are believed to be within the local universe (a few hundred megaparsecs), but deflections by intergalactic and ...Galactic magnetic fields prevent us from straightforwardly associating UHECRs to their sources based on their arrival directions, making their angular distribution mostly isotropic. At higher energies, the number of potential source candidates and the magnetic deflections are both expected to be smaller, but so is the available amount of statistics. Hence, it is interesting to perform searches for anisotropies using several different energy thresholds. With a threshold of 8 EeV a dipole modulation has been discovered, and with higher thresholds evidence is mounting for correlations with certain nearby galaxies. Neither of the two main UHECR detectors, the Pierre Auger Observatory and the Telescope Array project, has full-sky coverage. Full-sky searches require combining the datasets of both, and a working group with members of both collaborations has been tasked with this. We present an overview of the challenges encountered in such analyses, recent results from the working group, possible ways of interpreting them, and an outlook for the near future.
This study examines linkages between inequality, information and communication technology (ICT) and inclusive education in order to establish inequality thresholds that should not be exceeded in ...order for ICT to promote inclusive education in 42 countries in sub-Saharan Africa for the period 2004–2014. The empirical evidence is based on the Generalized Method of Moments. The following findings are established. First, a Gini coefficient and an Atkinson index of respectively, 0.400 and 0.625 are income inequality thresholds that should not be exceeded in order for internet penetration to positively influence inclusive education. Second, a Gini coefficient, an Atkinson index and a Palma ratio of respectively, 0.574, 0.676 and 9.000 are thresholds of income inequality that if exceeded, fixed broadband subscriptions will no longer positively affect inclusive education. As a main policy implication, the established inequality thresholds should not be exceeded in order for ICT to promote inclusive education in sampled countries. Other implications in the light of Sustainable Development Goals (SDGs) are discussed.
•This study examines linkages between inequality, ICT and inclusive education.•It establishes inequality thresholds at which ICT promotes inclusive education.•The focus is on 42 countries in sub-Saharan Africa for the period 2004–2014•The empirical evidence is based on the Generalized Method of Moments.•Implications of the study are relevant to Sustainable Development Goals.
This study investigates whether mobile phone penetration modulates the effect of different indicators of governance on some indicators of the ease of doing business in Sub-Saharan Africa with data ...from the period 2000–2012 by employing the Generalised Method of Moments. Three broad concepts of governance are explored: (i) political (comprising voice & accountability and political stability/no violence), (ii) economic (involving government effectiveness and regulation quality) and (iii) institutional (including corruption-control and rule of law). Ten dimensions of entrepreneurship are considered. Two main findings are established with respect to the net effects of the interaction between mobile phones and governance dynamics. They are (1) reduced cost of business start-up procedure, the time to build a warehouse and the time to resolve an insolvency and (2) increased time to enforce a contract, to register a property and to prepare and pay taxes. Implications for theory and policy are discussed. Some of the engaged policy implications include the following. (i) Measures on how to leverage on the potential of mobile phone penetration for entrepreneurship opportunities by addressing challenge of access to and affordability of mobile phones on the one hand and on the other hand, improving on the role of the mobile phone as a participative interface between emerging entrepreneurs and governance. (ii) The relevance of the mobile phone in mitigating information asymmetry between entrepreneurs and government institutions, notably by: reducing government inefficiency (which potentially represents an additional cost to doing business) and decreasing informational rents, bureaucracy and transaction costs.
•This study investigates how mobile phones modulate governance for doing business.•The focus is on Sub-Saharan Africa with data from the period 2000–2012.•The empirical evidence is based on Generalised Method of Moments.•The mobile phone has an appealing complementary role for some doing business dimensions.•Governance needs to be improved to enhance the complementary role of mobile phones.
Many citizens of European countries may soon experience a long and extensive blackout. The lack of predictability in the output of renewable energy sources, aggravating the problem of consistently ...matching supply with demand on electric grids, along with cyber-attacks or even worse unpredictable incidents in the electric grid are some factors that may mean a blackout is much more likely than in previous years. This paper covers the possibility of an extensive blackout in a country of the interconnected European electricity transmission system or, even worse, a blackout in a wide area of the European continent. The topic of this paper becomes even more important and timely given the energy crisis due to the war in Ukraine, which has made the possibility of a blackout in the winter of 2022–2023 high. First, the major European blackouts that occurred in the past 20 years are presented, examining their causes. On 8 January 2021, the European electricity grid was divided into two separate sections, with different frequencies; some additional scenarios are considered which, if they had happened, could have led to blackouts in some European countries or, even worse, a wide area of Europe. This work also examines how to avoid such an eventuality, as well as how European TSOs should react in case a blackout occurs. Focused on the fast and reliable supply of consumers after a blackout, a novel restoration strategy based on the A* Algorithm is presented. Its efficiency is validated in the IEEE-39 and IEEE-68 bus systems.
New methods for state estimation are required due to the complexity of the topology of transmission and distribution systems, and the predictability in the management of prosumer dispatch. This paper ...describes a pilot project in Greece that, in accordance with OneNet’s architecture, addresses the challenges of congestion and balancing management that system operators face due to the high penetration of renewable energy sources. The respective data requirements and the IT/OT environment are described, as well as the interconnections among the various modules and functionalities. Available resources of the grid’s flexibility are identified, and the implementation of an integrated monitoring system based on efficient forecasting of volatile generation and demand is addressed. Congestion management and frequency and voltage control are in the center of interest of the demonstrator where, in close collaboration with system operators, respective network models are being developed.
With the increase in the complexity of the topology of transmission and distribution systems, associated with the predictability in the management of the dispatch of prosumers, new techniques for ...state estimation, and application of metaheuristics are necessary. In the current work a pilot project in Greece that addresses the difficulties of congestion and balancing management that system operators face in the renewable energy sources era, in accordance with the OneNet’s architecture is described. Available resources of grid’s flexibility are identified, and the implementation of an integrated monitoring system based on weather conditions with an energy control and dispatch system in the Greek electricity grid is addressed. The document suggests that flexibility resources will derive through predictions that have been improved and efficient forecasts from increased spatial resolution Numerical Weather Predictions and integration of Artificial Intelligence preventing the power system of entering dangerous topological or operational states.
In the study of cosmic rays, the measurement of the energy spectrum of the primaries is one of the main issues and provides fundamental information on the most energetic phenomena in the Universe. At ...ultrahigh energies, beyond 10
18
eV, the cosmic rays are studied by the two largest observatories built so far, the Pierre Auger Observatory and the Telescope Array. Both observatories are based on a hybrid design and reported a measurement of the energy spectrum using the high duty cycle of the surface detector and the calorimetric estimation of the energy scale provided by the fluorescence detector.
The differences among the reported spectra are scrutinized by a working group made by members of the Pierre Auger and Telescope Array Collaborations. The two measurements have been found well in agreement below 10
19
eV while, at higher energies, they show an energy-dependent difference that is beyond the systematic uncertainties associated to the energy scale.
In this contribution we review the status and perspectives of the working group activities including new studies aiming at addressing the impact on the flux measurement at the highest energies of potential biases in the estimation of the shower size.
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