Design of beam optics for the Future Circular Collider e+e- -collider rings

A beam optics scheme has been designed for the Future Circular Collider-e+e- (FCC-ee). The main characteristics of the design are: beam energy 45 to 175 GeV, 100 km circumference with two interaction points (IPs) per ring, horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [1] with local chromaticity correction. The crab-waist scheme is implemented within the local chromaticity correction system without additional sextupoles, by reducing the strength of one of the two sextupoles for vertical chromatic correction at each side of the IP. So-called "tapering" of the magnets is applied, which scales all fields of the magnets according to the local beam energy to compensate for the effect of synchrotron radiation (SR) loss along the ring. An asymmetric layout near the interaction region reduces the critical energy of SR photons on the incoming side of the IP to values below 100 keV, while matching the geometry to the beam line of the FCC proton collider (FCC-hh) [2] as closely as possible. Sufficient transverse/longitudinal dynamic aperture (DA) has been obtained, including major dynamical effects, to assure an adequate beam lifetime in the presence of beamstrahlung and top-up injection. In particular, a momentum acceptance larger than +/-2% has been obtained, which is better than the momentum acceptance of typical collider rings by about a factor of 2. The effects of the detector solenoids including their compensation elements are taken into account as well as synchrotron radiation in all magnets. The optics presented in this paper is a step toward a full conceptual design for the collider. A number of issues have been identified for further study

Lattice Design and Dynamic Aperture Studies for the FCC-ee Top-Up Booster Synchrotron

The Future Circular Collider (FCC) study investigates the feasibility of circular colliders in the post-LHC era. The sub-study FCC-ee is a 100 km electron positron collider in the energy range of 90-365 GeV. In order to achieve a design luminosity in the order of 1036cm−2s−1 continuous top-up injection is required. The injector chain therefore includes a 100 km booster synchrotron in the same tunnel as the collider rings. This paper presents the lattice design of this booster synchrotron and the first dynamic aperture studies based on the chromaticity correction sextupole scheme

Lattice Design and Dynamic Aperture Studies for the FCC-ee Top-Up Booster Synchrotron

The Future Circular Collider (FCC) study investigates the feasibility of circular colliders in the post-LHC era. The sub-study FCC-ee is a 100 km electron positron collider in the energy range of 90-365 GeV. In order to achieve a design luminosity in the order of 1036cm−2s−1 continuous top-up injection is required. The injector chain therefore includes a 100 km booster synchrotron in the same tunnel as the collider rings. This paper presents the lattice design of this booster synchrotron and the first dynamic aperture studies based on the chromaticity correction sextupole scheme

Evaluating the Importance of Fisheries to US Security and the Opportunities for Strategic Investments in Aquaculture to Strengthen the US Position in Competition with China

How important are fisheries to the most important strategic risks for the United States? Can a broader thinking about what should constitute food security allow the US to invest strategically in aquaculture while enhancing its position in geostrategic competition with China? I find in this study that the US does have opportunities to help some other strategically important countries address shortfalls they might experience if wild-capture fisheries were to collapse. That can help their food security and the US’ national security simultaneously by helping keep countries stable. But I also find that the US is significantly lagging behind China’s global aquaculture leadership, and that US actions to catch up would need drastic levels of infrastructure funding. I identify that the Chinese aquaculture industry is so far advanced relative to other countries that they would control nearly half of the world market for fish by 2035 should capture fisheries collapse. I also find that numerous countries of strategic importance to either the US, China, or to both, are very reliant on fisheries compared with the global average. The research identifies that an absence of strategic action by the US will ensure that China’s aquaculture advantage will allow it to be the key global provider of a critical resource demanded by many countries of interest to the two countries, granting Beijing extreme leverage in food security over those countries and an improvement in the security competition with the US

Esophageal sphincter device for gastroesophageal reflux disease

BACKGROUND Patients with gastroesophageal reflux disease who have a partial response to proton-pump inhibitors often seek alternative therapy. We evaluated the safety and effectiveness of a new magnetic device to augment the lower esophageal sphincter. METHODS We prospectively assessed 100 patients with gastroesophageal reflux disease before and after sphincter augmentation. The study did not include a concurrent control group. The primary outcome measure was normalization of esophageal acid exposure or a 50% or greater reduction in exposure at 1 year. Secondary outcomes were 50% or greater improvement in quality of life related to gastroesophageal reflux disease and a 50% or greater reduction in the use of proton-pump inhibitors at 1 year. For each outcome, the prespecified definition of successful treatment was achievement of the outcome in at least 60% of the patients. The 3-year results of a 5-year study are reported. RESULTS The primary outcome was achieved in 64% of patients (95% confidence interval [CI], 54 to 73). For the secondary outcomes, a reduction of 50% or more in the use of proton-pump inhibitors occurred in 93% of patients, and there was improvement of 50% or more in quality-of-life scores in 92%, as compared with scores for patients assessed at baseline while they were not taking proton-pump inhibitors. The most frequent adverse event was dysphagia (in 68% of patients postoperatively, in 11% at 1 year, and in 4% at 3 years). Serious adverse events occurred in six patients, and in six patients the device was removed. CONCLUSIONS In this single-group evaluation of 100 patients before and after sphincter augmentation with a magnetic device, exposure to esophageal acid decreased, reflux symptoms improved, and use of proton-pump inhibitors decreased. Follow-up studies are needed to assess long-term safety. (Funded by Torax Medical; ClinicalTrials.gov number, NCT00776997.

Literaturanalyse zur Identifikation und Kategorisierung von Ansätzen der Studiengangsentwicklung

Aufgrund einer verstärkten Nachfrage nach neuen und passenderen Studiengängen aus der Arbeitswelt, rückt die Studiengangsentwicklung in den Forschungs-mittelpunkt. Es existieren eine Vielzahl von unterschiedlichen Ansätzen zur Ent-wicklung von Studiengängen. Zusätzlich wird die Relevanz des Themas durch makropolitische Aktivitäten gefördert. Darum soll mit diesem Beitrag der aktuelle Literaturstand der Ansätze zur Studiengangsentwicklung über alle wichtigen Wissenschaftsdisziplinen hinweg identifiziert und kategorisiert werden. Praxisimplikationen und ein Forschungsausblick schließen den Beitrag ab

QUANTITATIVE CLINICAL NEUROLOGICAL TESTING. I. A STUDY OF A BATTERY OF TESTS DESIGNED TO EVALUATE IN PART THE NEUROLOGICAL FUNCTION OF PATIENTS WITH MULTIPLE SCLEROSIS AND ITS USE IN A THERAPEUTIC TRIAL *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73100/1/j.1749-6632.1965.tb20231.x.pd

On the Perturbation of Synchrotron Motion in the Micro-Bunching Instability

The self-interaction of short electron bunches with their own radiation field can have a significant impact on the longitudinal beam dynamics in a storage ring. While higher bunch currents increase the power of the emitted CSR which can be provided to dedicated experiments, it simultaneously amplifies the strength of the self-interaction. Eventually, this leads to the formation of dynamically changing micro-structures within the bunch and thus fluctuating CSR emission, a phenomenon that is generally known as micro-bunching or micro-wave instability. The underlying longitudinal dynamics can be simulated by solving the VFP equation, where the CSR self-interaction can be added as a perturbation to the Hamiltonian. In this contribution, we focus on the perturbation of the synchrotron motion that is caused by introducing this additional wake field. Therefore, we adopt the perspective of a single particle and eventually comment on its implications for collective motion. We explicitly show how the shape of the parallel plates CSR wake potential breaks homogeneity in the longitudinal phase space and propose a quadrupole-like mode as potential seeding mechanism of the micro-bunching instability. Moreover, we consider synchrotron motion above the instability threshold and thereby motivate an approach to control of the occurring micro-bunching dynamics. Using dynamically adjusted RF amplitude modulations we can directly address the continuous CSR-induced perturbation at the timescale of its occurrence, which allows for substantial control over the longitudinal charge distribution. While the approach is not limited to this particular application, we demonstrate how this can significantly mitigate the micro-bunching dynamics directly above the instability threshold. The gained insights are supported and verified using the VFP solver Inovesa and put into context with measurements at KARA