New constraints on the up-quark valence distribution in the proton

The high-$x$ data from the ZEUS Collaboration are used to extract parton density distributions of the proton deep in the perturbative regime of QCD. The data primarily constrain the up-quark valence distribution and new results are presented on its $x$-dependence as well as on the momentum carried by the up-quark. The results were obtained using Bayesian analysis methods which can serve as a model for future parton density extractions.Comment: Minor changes in final published versio

Relaxation Height in Energy Landscapes: an Application to Multiple Metastable States

The study of systems with multiple (not necessarily degenerate) metastable states presents subtle difficulties from the mathematical point of view related to the variational problem that has to be solved in these cases. We introduce the notion of relaxation height in a general energy landscape and we prove sufficient conditions which are valid even in presence of multiple metastable states. We show how these results can be used to approach the problem of multiple metastable states via the use of the modern theories of metastability. We finally apply these general results to the Blume--Capel model for a particular choice of the parameters ensuring the existence of two multiple, and not degenerate in energy, metastable states

Neural Network Based Approach to Recognition of Meteor Tracks in the Mini-EUSO Telescope Data

Mini-EUSO is a wide-angle fluorescence telescope that registers ultraviolet (UV) radiation in the nocturnal atmosphere of Earth from the International Space Station. Meteors are among multiple phenomena that manifest themselves not only in the visible range but also in the UV. We present two simple artificial neural networks that allow for recognizing meteor signals in the Mini-EUSO data with high accuracy in terms of a binary classification problem. We expect that similar architectures can be effectively used for signal recognition in other fluorescence telescopes, regardless of the nature of the signal. Due to their simplicity, the networks can be implemented in onboard electronics of future orbital or balloon experiments.Comment: 15 page

Effect of remote ischaemic conditioning on clinical outcomes in patients with acute myocardial infarction (CONDI-2/ERIC-PPCI): a single-blind randomised controlled trial.

BACKGROUND: Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months. METHODS: We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed. FINDINGS: Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed. INTERPRETATION: Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI. FUNDING: British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden

Cosmic clues from astrophysical particles

Ultra-high-energy cosmic rays (UHECRs) are charged particles that have been accelerated to extreme energies, such that they are effectively travelling at the speed of light. Interactions of these particles with the Earth’s atmosphere lead to the development of extensive showers of particles and radiation that can be measured with existing technology. Despite decades of research, the origins of UHECRs remain mysterious. However, they are thought to be accelerated within powerful astrophysical sources that lie beyond the borders of our Galaxy. This thesis explores different ideas towards the common goal of reaching a deeper understanding of UHECR phenomenology. Part I concerns the development of a novel space-based observatory that has the potential to detect unprecedented numbers of these enigmatic particles. The feasibility of such a project is demonstrated by the results from the Mini-EUSO instrument, a small ultraviolet telescope that is currently on-board the International Space Station. In Part II, the focus is on fully exploiting the available information with advanced analysis techniques to close the gap between theory and data. UHECRs are closely connected to the production of neutrinos and gamma rays, so frameworks for the joint analysis of these complementary cosmic messengers are also developed. The results presented herein demonstrate that to progress, it is crucial to invest in the development of both detection and analysis techniques. By taking a closer look at the existing data, new clues can be revealed to reach a more comprehensive understanding and better inform the design of future experiments. Ultrahög energetisk kosmisk strålning (UHECR) är laddade partiklar som har accelererats till extrema energier, så att de i praktiken färdas med ljusets hastighet. Det är möjligt att upptäcka dessa partiklar när de växelverkar med jordens atmosfär då omfattande skurar med partiklar och strålning utvecklas, vilka kan mätas med befintlig teknik. Trots decennier av forskning förblir UHECR:s ursprung dold. Men de tros vara accelererade inom kraftfulla astrofysiska källor som ligger utanför vår galax. Denna avhandling utforskar olika idéer med det gemensamma målet att nå en djupare förståelse av UHECR-fenomenologin. Del I handlar om utvecklingen av ett nytt rymdbaserat observatorium som har potential att upptäcka ett stort antal av dessa gåtfulla partiklar. Genomförandet av ett sådant projekt demonstreras av resultaten från Mini-EUSO-instrumentet som för närvarande är ombord på den Internationella rymdstationen. I Del II ligger fokus på att utnyttja tillgänglig information med avancerade analystekniker för att minska klyftan mellan teori och data, för att nå en djupare förståelse av aktuella observationer. UHECR:er är nära kopplade till produktionen av neutriner och gammastrålning. Ramar för gemensam analys av dessa komplementära kosmiska budbärare utvecklas. Resultaten som presenteras här visar att det är avgörande att investera i utvecklingen av både detekterings- och analystekniker för att gå vidare. Genom att titta närmare på befintliga data kan nya ledtrådar avslöjas i sammanhanget med så kallade multi-budbärare och ger information för att bättre utforma framtida experiment.

Cosmic clues from astrophysical particles

Ultra-high-energy cosmic rays (UHECRs) are charged particles that have been accelerated to extreme energies, such that they are effectively travelling at the speed of light. Interactions of these particles with the Earth’s atmosphere lead to the development of extensive showers of particles and radiation that can be measured with existing technology. Despite decades of research, the origins of UHECRs remain mysterious. However, they are thought to be accelerated within powerful astrophysical sources that lie beyond the borders of our Galaxy. This thesis explores different ideas towards the common goal of reaching a deeper understanding of UHECR phenomenology. Part I concerns the development of a novel space-based observatory that has the potential to detect unprecedented numbers of these enigmatic particles. The feasibility of such a project is demonstrated by the results from the Mini-EUSO instrument, a small ultraviolet telescope that is currently on-board the International Space Station. In Part II, the focus is on fully exploiting the available information with advanced analysis techniques to close the gap between theory and data. UHECRs are closely connected to the production of neutrinos and gamma rays, so frameworks for the joint analysis of these complementary cosmic messengers are also developed. The results presented herein demonstrate that to progress, it is crucial to invest in the development of both detection and analysis techniques. By taking a closer look at the existing data, new clues can be revealed to reach a more comprehensive understanding and better inform the design of future experiments. Ultrahög energetisk kosmisk strålning (UHECR) är laddade partiklar som har accelererats till extrema energier, så att de i praktiken färdas med ljusets hastighet. Det är möjligt att upptäcka dessa partiklar när de växelverkar med jordens atmosfär då omfattande skurar med partiklar och strålning utvecklas, vilka kan mätas med befintlig teknik. Trots decennier av forskning förblir UHECR:s ursprung dold. Men de tros vara accelererade inom kraftfulla astrofysiska källor som ligger utanför vår galax. Denna avhandling utforskar olika idéer med det gemensamma målet att nå en djupare förståelse av UHECR-fenomenologin. Del I handlar om utvecklingen av ett nytt rymdbaserat observatorium som har potential att upptäcka ett stort antal av dessa gåtfulla partiklar. Genomförandet av ett sådant projekt demonstreras av resultaten från Mini-EUSO-instrumentet som för närvarande är ombord på den Internationella rymdstationen. I Del II ligger fokus på att utnyttja tillgänglig information med avancerade analystekniker för att minska klyftan mellan teori och data, för att nå en djupare förståelse av aktuella observationer. UHECR:er är nära kopplade till produktionen av neutriner och gammastrålning. Ramar för gemensam analys av dessa komplementära kosmiska budbärare utvecklas. Resultaten som presenteras här visar att det är avgörande att investera i utvecklingen av både detekterings- och analystekniker för att gå vidare. Genom att titta närmare på befintliga data kan nya ledtrådar avslöjas i sammanhanget med så kallade multi-budbärare och ger information för att bättre utforma framtida experiment.

Cosmic clues from astrophysical particles

Ultra-high-energy cosmic rays (UHECRs) are charged particles that have been accelerated to extreme energies, such that they are effectively travelling at the speed of light. Interactions of these particles with the Earth’s atmosphere lead to the development of extensive showers of particles and radiation that can be measured with existing technology. Despite decades of research, the origins of UHECRs remain mysterious. However, they are thought to be accelerated within powerful astrophysical sources that lie beyond the borders of our Galaxy. This thesis explores different ideas towards the common goal of reaching a deeper understanding of UHECR phenomenology. Part I concerns the development of a novel space-based observatory that has the potential to detect unprecedented numbers of these enigmatic particles. The feasibility of such a project is demonstrated by the results from the Mini-EUSO instrument, a small ultraviolet telescope that is currently on-board the International Space Station. In Part II, the focus is on fully exploiting the available information with advanced analysis techniques to close the gap between theory and data. UHECRs are closely connected to the production of neutrinos and gamma rays, so frameworks for the joint analysis of these complementary cosmic messengers are also developed. The results presented herein demonstrate that to progress, it is crucial to invest in the development of both detection and analysis techniques. By taking a closer look at the existing data, new clues can be revealed to reach a more comprehensive understanding and better inform the design of future experiments. Ultrahög energetisk kosmisk strålning (UHECR) är laddade partiklar som har accelererats till extrema energier, så att de i praktiken färdas med ljusets hastighet. Det är möjligt att upptäcka dessa partiklar när de växelverkar med jordens atmosfär då omfattande skurar med partiklar och strålning utvecklas, vilka kan mätas med befintlig teknik. Trots decennier av forskning förblir UHECR:s ursprung dold. Men de tros vara accelererade inom kraftfulla astrofysiska källor som ligger utanför vår galax. Denna avhandling utforskar olika idéer med det gemensamma målet att nå en djupare förståelse av UHECR-fenomenologin. Del I handlar om utvecklingen av ett nytt rymdbaserat observatorium som har potential att upptäcka ett stort antal av dessa gåtfulla partiklar. Genomförandet av ett sådant projekt demonstreras av resultaten från Mini-EUSO-instrumentet som för närvarande är ombord på den Internationella rymdstationen. I Del II ligger fokus på att utnyttja tillgänglig information med avancerade analystekniker för att minska klyftan mellan teori och data, för att nå en djupare förståelse av aktuella observationer. UHECR:er är nära kopplade till produktionen av neutriner och gammastrålning. Ramar för gemensam analys av dessa komplementära kosmiska budbärare utvecklas. Resultaten som presenteras här visar att det är avgörande att investera i utvecklingen av både detekterings- och analystekniker för att gå vidare. Genom att titta närmare på befintliga data kan nya ledtrådar avslöjas i sammanhanget med så kallade multi-budbärare och ger information för att bättre utforma framtida experiment.