LHC/FCC-based muon colliders Zimmermann, F.
Journal of physics. Conference series,
09/2018, Letnik:
1067, Številka:
2
Journal Article
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In recent years, three schemes for producing low-emittance muon beams have been proposed: (1) positron-electron annihilation above threshold using a positron storage ring with a thin target, (2) ...laser/FEL-photon back-scattering off high-energy proton beams circulating in the LHC or FCC-hh, (3) the Gamma factory concept where partially stripped heavy ions collide with a laser pulse to directly generate muons. The Gamma factory would also deliver copious amounts of positrons which could in turn be used as source for option (1). On the other hand the top-up booster of the FCC-ee design would be an outstanding positron storage ring, at the right beam energy, around 45 GeV. After rapid acceleration the muons, produced in one of the three or four ways, could be collided in machines like the SPS, LHC or FCC-hh. Possible collider layouts are suggested.
We sketch the actual European and international strategies and possible future facilities. In the near term the High Energy Physics (HEP) community will fully exploit the physics potential of the ...Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). Post-LHC options include a linear e+e− collider in Japan (ILC) or at CERN (CLIC), as well as circular lepton or hadron colliders in China (CepC/SppC) and Europe (FCC). We conclude with linear and circular acceleration approaches based on crystals, and some perspectives for the far future of accelerator-based particle physics.
Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such ...type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency is also addressed.
Multijunction solar cells can overcome the fundamental efficiency limits of single-junction devices. The bandgap tunability of metal halide perovskite solar cells renders them attractive for ...multijunction architectures
. Combinations with silicon and copper indium gallium selenide (CIGS), as well as all-perovskite tandem cells, have been reported
. Meanwhile, narrow-gap non-fullerene acceptors have unlocked skyrocketing efficiencies for organic solar cells
. Organic and perovskite semiconductors are an attractive combination, sharing similar processing technologies. Currently, perovskite-organic tandems show subpar efficiencies and are limited by the low open-circuit voltage (V
) of wide-gap perovskite cells
and losses introduced by the interconnect between the subcells
. Here we demonstrate perovskite-organic tandem cells with an efficiency of 24.0 per cent (certified 23.1 per cent) and a high V
of 2.15 volts. Optimized charge extraction layers afford perovskite subcells with an outstanding combination of high V
and fill factor. The organic subcells provide a high external quantum efficiency in the near-infrared and, in contrast to paradigmatic concerns about limited photostability of non-fullerene cells
, show an outstanding operational stability if excitons are predominantly generated on the non-fullerene acceptor, which is the case in our tandems. The subcells are connected by an ultrathin (approximately 1.5 nanometres) metal-like indium oxide layer with unprecedented low optical/electrical losses. This work sets a milestone for perovskite-organic tandems, which outperform the best p-i-n perovskite single junctions
and are on a par with perovskite-CIGS and all-perovskite multijunctions
.
Studying activity patterns and temporal overlap among carnivores and their putative prey is difficult because of their secretive and elusive nature. With large carnivores declining worldwide, it is ...imperative for conservation planning that we understand how large carnivores interact with their prey and competitors. Camera trapping offers a promising avenue to address this issue. We investigated temporal overlap between male and female leopards, their known and putative prey as well as their competitor, the spotted hyenas, in the Udzungwa Mountains of Tanzania. Data consisted of 4297 independent events from a 30 min interval criterion from 164 camera trap sites we sampled. Leopards were captured by camera traps throughout the day, with male and female leopards showing significantly different activity patterns (P < 0.001) indicating sexual segregation in activity patterns, with male leopards being more nocturnal than female leopards. Leopards had significantly different activity patterns from that of the majority of their prey, with yellow baboons, that displayed peak activity during midday, that had the least overlap. Moreover, both male and female leopards had significantly different activity patterns from that of spotted hyenas (P = <0.001), with female leopards appearing to be inactive during hours with peak hyena activity. We conclude that systematic camera trapping is a useful tool to study activity patterns and temporal niche interactions between sympatric carnivores and, to a lesser extent, their prey.
Studying activity pattern overlap among carnivores, and their prey is difficult because of their secretive nature. Using camera traps, we investigated temporal overlap between male and female leopards, their prey as well as their competitor, the spotted hyena. Leopards were found to be cathemeral, with male and female leopards showing significantly different activity patterns from each other and also significantly different activity patterns from those of the majority of their prey. Moreover, both male and female leopards had significantly different activity patterns from those of spotted hyenas, with female leopards appearing to be inactive during the hours with peak hyena activity. We conclude that systematic camera trapping is a useful tool to study activity patterns and temporal niche interactions between sympatric carnivores and, to a lesser extent, their prey.
•Epimerization of procyanidin dimers and trimers during cocoa bean roasting was discovered.•The extent of epimerization during cocoa bean roasting is a function of temperature.•The change of flavanol ...content varied remarkably, when different cocoa beans were roasted under equal conditions.
Cocoa consumption is suggested to promote many health benefits, since cocoa is a rich source of flavanols; but amounts and profiles of flavanols depend strongly on the bean type, origin and manufacturing process. Roasting is known as a crucial step in technical treatment of cocoa, which leads to flavanol losses and modifications, especially the epimerization of (−)-epicatechin to (−)-catechin. This study monitors the influence of cocoa bean roasting on the composition of flavanol monomers to trimers, with special focus on epimerization, which was quantified for procyanidin dimers, and also observed for trimers for the first time. Five dimeric and two trimeric potential epimerization products were detected and the extent of epimerization during cocoa roasting was shown to be a function of temperature. The data also showed remarkable variations in the change of flavanol content. The quantified flavanols decreased about 50% in Java beans and increased about 30% in Ivory Coast beans, despite being roasted under equal conditions.
Abstract
Recent investigations have shown that neutral molecules may be trapped by the electromagnetic field of a charged particle beam. This effect changes the residual gas distribution according to ...a characteristic temperature of the system consisting of beam and residual gas. Here, we investigate the effect of the modified gas density profile on the beam lifetime.
Our large-scale experiment with 542 families from rural Bangladesh finds substantial intergenerational persistence of economic preferences. Both mothers’ and fathers’ risk, time, and social ...preferences are significantly (and largely to the same degree) positively correlated with their children’s economic preferences, even when controlling for personality traits and socioeconomic background. We discuss possible transmission channels and are the first to classify all families into one of two clusters, with either relatively patient, risk-tolerant, and prosocial members or relatively impatient, risk averse, and spiteful members. Classifications correlate with socioeconomic background variables. We find that our results differ from evidence for rich countries.
Background Heart Rate Variability (HRV) represents efferent vagus nerve activity which is suggested to be inversely related to fundamental mechanisms of tumorigenesis and to be a predictor of ...prognosis in various types of cancer. HRV is also believed to predict the occurrence and severity of post-operative complications. We aimed to determine the role of pre-operative HRV as a prognostic factor in overall and cancer free survival in patients with colorectal cancer. Methods Retrospective analysis was performed in a detailed dataset of patients diagnosed with primary colorectal cancer between January 2010 and December 2016, who underwent curative surgical treatment. HRV was measured as time-domain parameters (SDNN (Standard Deviation of NN-intervals) and RMSSD (Root Mean Square of Successive Differences)) based on pre-operative 10 second ECGs. Groups were created by baseline HRV: Low HRV (SDNN 20ms or RMSSD 19ms) and normal HRV (SDNN greater than or equal to20ms or RMSSD greater than or equal to19ms). Primary endpoints were overall and cancer free survival. Results A total of 428 patients were included in this study. HRV was not significantly associated with overall survival (SDNN 20ms vs SDNN greater than or equal to20ms:24.4% vs 22.8%, adjusted HR = 0.952 (0.607-1.493), p = 0.829; RMSSD 19ms vs RMSSD greater than or equal to19ms:27.0% vs 19.5%, adjusted HR = 1.321 (0.802-2.178), p = 0.274) or cancer recurrence (SDNN 20ms vs greater than or equal to20ms:20.1% vs 18.7%, adjusted HR = 0.976 (0.599-1.592), p = 0.924; RMSSD 19ms vs greater than or equal to19ms, 21.5% vs 16.9%, adjusted HR = 1.192 (0.706-2.011), p = 0.511). There was no significant association between HRV and CEA-level at one year follow-up, or between HRV and occurrence of a post-operative complication or the severity of post-operative complications. Conclusions Heart rate variability was not associated with overall or cancer free survival in patients with primary colorectal cancer who underwent curative surgical treatment. These results do not align with results found in studies including only patients with advanced cancer, which suggests that there is only an association in the other direction, cancer causing low HRV.
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