1,631 research outputs found

    Transverse momentum distribution of vector mesons produced in ultraperipheral relativistic heavy ion collisions

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    We study the transverse momentum distribution of vector mesons produced in ultraperipheral relativistic heavy ion collisions (UPCs). In UPCs there is no strong interaction between the nuclei and the vector mesons are produced in photon-nucleus collisions where the (quasireal) photon is emitted from the other nucleus. Exchanging the role of both ions leads to interference effects. A detailed study of the transverse momentum distribution which is determined by the transverse momentum of the emitted photon, the production process on the target and the interference effect is done. We study the total unrestricted cross section and those, where an additional electromagnetic excitation of one or both of the ions takes place in addition to the vector meson production, in the latter case small impact parameters are emphasized.Comment: 12 pages, REVTeX manuscrip

    Thermal Instability of Porous Gold Nanowires

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    Cognitive Understanding of Reverse Engineering Assistant

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    The Cognitive Understanding of Reverse Engineering Assistant, or C.U.R.E. Assistant for short, is an independently developed program with the purpose of introducing students of the software reverse-engineering world to the art of disassembly. Reverse Engineering, or R.E. for short, is the process of deducing the source instructions or mechanisms of a device. This can be done to software to figure out how it works and how it can be exploited. While hackers employ this method for breaking into software systems, this is very useful for security researchers to determine security vulnerabilities in internet browsers, operating systems, apps, and more, so they can fix the problems before people using the software get exploited. Unfortunately, this is a very difficult and even expensive skill to learn, but C.U.R.E. Assistant seeks to mitigate that effort and cost. By analyzing a binary and then displaying the results in a user-friendly graphical interface, C.U.R.E. Assistant is able to point out areas of interest to those who may not know what to look for or where to start. In addition, it is designed with added functionality to ease users into learning the intricate, but popular, reverse-engineering tool, Radare2. Inspired by the massive learning curve and scant available training for software dissection, C.U.R.E. Assistant aims to both streamline the process for experienced engineers as well as educate those new to the field in a friendly and informative manner

    Irradiation-induced effects in organic thin PMMA films

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    Improved radiative corrections for (e,e'p) experiments - A novel approach to multi-photon bremsstrahlung

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    Radiative processes lead to important corrections to (e,e'p) experiments. While radiative corrections can be calculated exactly in QED and to a good accuracy also including hadronic corrections, these corrections cannot be included into data analyses to arbitrary orders exactly. Nevertheless consideration of multi-photon bremsstrahlung above the low-energy cut-off is important for many (e,e'p) experiments. To date, higher-order bremsstrahlung effects concerning electron scattering experiments have been implemented approximately by employing the soft-photon approximation (SPA). In this paper we propose a novel approach to multi-photon emission which partially removes the SPA from (e,e'p) experiments. In this combined approach one hard photon is treated exactly; and additional softer bremsstrahlung photons are taken into account resorting to the soft-photon approximation. This partial removal of the soft-photon approximation is shown to be relevant for the missing-energy distribution for several kinematic settings at MAMI and TJNAF energies.Comment: 10 pages, 21 figure

    Transition from participant to spectator fragmentation in Au+Au reaction between 60 AMeV and 150 AMeV

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    Using the quantum molecular dynamics approach, we analyze the results of the recent INDRA Au+Au experiments at GSI in the energy range between 60 AMeV and 150 AMeV. It turns out that in this energy region the transition toward a participant-spectator scenario takes place. The large Au+Au system displays in the simulations as in the experiment simultaneously dynamical and statistical behavior which we analyze in detail: The composition of fragments close to midrapidity follows statistical laws and the system shows bi-modality, i.e. a sudden transition between different fragmentation pattern as a function of the centrality as expected for a phase transition. The fragment spectra at small and large rapidities, on the other hand, are determined by dynamics and the system as a whole does not come to equilibrium, an observation which is confirmed by FOPI experiments for the same system.Comment: published versio

    Prevalence and severity of mental disorders in military personnel: a standardised comparison with civilians

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    Aims. Provision and need for mental health services among military personnel are a major concern across nations. Two recent comparisons suggest higher rates of mental disorders in US and UK military personnel compared with civilians. However, these findings may not apply to other nations. Previous studies have focused on the overall effects of military service rather than the separate effects of military service and deployment. This study compared German military personnel with and without a history of deployment to sociodemographically matched civilians regarding prevalence and severity of 12-month DSM-IV mental disorders. Method. 1439 deployed soldiers (DS), 779 never deployed soldiers (NS) and 1023 civilians were assessed with an adapted version of the Munich Composite International Diagnostic interview across the same timeframe. Data were weighted using propensity score methodology to assure comparability of the three samples. Results. Compared with adjusted civilians, the prevalence of any 12-month disorder was lower in NS (OR: 0.7, 95% CI: 0.5–0.99) and did not differ in DS. Significant differences between military personnel and civilians regarding prevalence and severity of individual diagnoses were only apparent for alcohol (DS: OR: 0.3, 95% CI: 0.1–0.6; NS: OR: 0.2, 95% CI: 0.1–0.6) and nicotine dependence (DS: OR: 0.5, 95% CI: 0.3–0.6; NS: OR: 0.5, 95% CI: 0.3–0.7) with lower values in both military samples. Elevated rates of panic/agoraphobia (OR: 2.7, 95% CI: 1.4–5.3) and posttraumatic stress disorder (OR: 3.2, 95% CI: 1.3–8.0) were observed in DS with high combat exposure compared with civilians. Conclusions. Rates and severity of mental disorders in the German military are comparable with civilians for internalising and lower for substance use disorders. A higher risk of some disorders is reduced to DS with high combat exposure. This finding has implications for mental health service provision and the need for targeted interventions. Differences to previous US and UK studies that suggest an overall higher prevalence in military personnel might result from divergent study methods, deployment characteristics, military structures and occupational factors. Some of these factors might yield valuable targets to improve military mental health
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