Course Notes: United States Particle Accelerator School Beam Physics with Intense Space-Charge

The purpose of this course is to provide a comprehensive introduction to the physics of beams with intense space charge. This course is suitable for graduate students and researchers interested in accelerator systems that require sufficient high intensity where mutual particle interactions in the beam can no longer be neglected. This course is intended to give the student a broad overview of the dynamics of beams with strong space charge. The emphasis is on theoretical and analytical methods of describing the acceleration and transport of beams. Some aspects of numerical and experimental methods will also be covered. Students will become familiar with standard methods employed to understand the transverse and longitudinal evolution of beams with strong space charge. The material covered will provide a foundation to design practical architectures. In this course, we will introduce you to the physics of intense charged particle beams, focusing on the role of space charge. The topics include: particle equations of motion, the paraxial ray equation, and the Vlasov equation; 4-D and 2-D equilibrium distribution functions (such as the Kapchinskij-Vladimirskij, thermal equilibrium, and Neuffer distributions), reduced moment and envelope equation formulations of beam evolution; transport limits and focusing methods; the concept of emittance and the calculation of its growth from mismatches in beam envelope and from space-charge non-uniformities using system conservation constraints; the role of space-charge in producing beam halos; longitudinal space-charge effects including small amplitude and rarefaction waves; stable and unstable oscillation modes of beams (including envelope and kinetic modes); the role of space charge in the injector; and algorithms to calculate space-charge effects in particle codes. Examples of intense beams will be given primarily from the ion and proton accelerator communities with applications from, for example, heavy-ion fusion, spallation neutron sources, nuclear waste transmutation, etc

Quantum Cryptography Using Single Particle Entanglement

A quantum cryptography scheme based on entanglement between a single particle state and a vacuum state is proposed. The scheme utilizes linear optics devices to detect the superposition of the vacuum and single particle states. Existence of an eavesdropper can be detected by using a variant of Bell's inequality.Comment: 4 pages, 3figures, revte

Ondansetron use in early pregnancy and the risk of late pregnancy outcomes

Background: The effects of ondansetron, used off-label to treat nausea and vomiting during pregnancy, on common pregnancy complications are understudied. Modest effects of a commonly used drug could result in adverse events for large numbers of pregnant women. Therefore, our objective was to compare the risk of stillbirth, preterm birth, gestational hypertensive disorders, small for gestational age, and differences in birth weight between women prescribed ondansetron and women prescribed alternative antiemetics in early pregnancy. Methods: A cohort of pregnant women receiving a prescription for ondansetron or comparator antiemetics (metoclopramide or promethazine) during the first 20 weeks of pregnancy was identified using electronic health record data from a health care system in North Carolina, USA. Confounding by multiple covariates was controlled using stabilized inverse probability of treatment weights. Weighted hazard ratios (HR) and 95% confidence intervals (CI) accounted for competing events. Results: We identified 2677 eligible pregnancies with antiemetic orders, 66% for ondansetron. The small number of stillbirths (n = 15) resulted in an imprecise estimate of the association with ondansetron (HR = 1.60; 95%CI 0.51, 4.97). No association was observed for preterm birth (HR = 0.90; 95%CI 0.67, 1.20) or gestational hypertensive disorders (HR = 0.87; 95%CI 0.68, 1.12). We observed an association with small for gestational age (HR = 1.37; 95%CI 0.98, 1.90), however mean birth weight among term births was similar between groups. Conclusions: Our results do not suggest that ondansetron increases the risk of preterm birth or gestational hypertensive disorders. The weak association observed between ondansetron use and small for gestational age warrants further investigation

Ondansetron use in early pregnancy and the risk of miscarriage

Background: Ondansetron is commonly used to treat nausea and vomiting in pregnancy despite inconclusive evidence of its safety. Previous studies have reported no increase in risk of miscarriage but relied on methods that failed to account for gestational weeks at risk and non-user comparators, which may increase the potential for unmeasured confounding. Our objective was to estimate the risk of miscarriage among women prescribed ondansetron vs alternative antiemetics during the first 20 weeks of pregnancy. Methods: A pregnancy cohort was created using electronic health record data from a health care system in North Carolina. Women were classified as exposed to either ondansetron or comparator antiemetics (metoclopramide or promethazine) based on the first antiemetic prescription received in the first 20 weeks of gestation. Cumulative incidence of miscarriage at 20 weeks was estimated in each antiemetic group. Hazard ratios (HR) were estimated with 95% confidence intervals and measured confounding was controlled using inverse probability of treatment weights. Sensitivity analyses assessed the potential impact of exposure misclassification, latency period, and selection bias. Results: We identified 2620 eligible pregnancies with antiemetic orders; 65% had a first ondansetron order and 35% had a first comparator antiemetic order. In total, 95 women had a miscarriage. After adjustment, there was no difference in risk of miscarriage (HR 1.21, 95% CI 0.77, 1.90). Results from the per-protocol and other sensitivity analyses were similar to the main analysis. Conclusions: We did not observe an increase in the risk of miscarriage for pregnancies exposed to ondansetron vs comparator antiemetics

Methanogenic archaea use a bacteria-like methyltransferase system to demethoxylate aromatic compounds

Methane-generating archaea drive the final step in anaerobic organic compound mineralization and dictate the carbon flow of Earth’s diverse anoxic ecosystems in the absence of inorganic electron acceptors. Although such Archaea were presumed to be restricted to life on simple compounds like hydrogen (H(2)), acetate or methanol, an archaeon, Methermicoccus shengliensis, was recently found to convert methoxylated aromatic compounds to methane. Methoxylated aromatic compounds are important components of lignin and coal, and are present in most subsurface sediments. Despite the novelty of such a methoxydotrophic archaeon its metabolism has not yet been explored. In this study, transcriptomics and proteomics reveal that under methoxydotrophic growth M. shengliensis expresses an O-demethylation/methyltransferase system related to the one used by acetogenic bacteria. Enzymatic assays provide evidence for a two step-mechanisms in which the methyl-group from the methoxy compound is (1) transferred on cobalamin and (2) further transferred on the C(1)-carrier tetrahydromethanopterin, a mechanism distinct from conventional methanogenic methyl-transfer systems which use coenzyme M as final acceptor. We further hypothesize that this likely leads to an atypical use of the methanogenesis pathway that derives cellular energy from methyl transfer (Mtr) rather than electron transfer (F(420)H(2) re-oxidation) as found for methylotrophic methanogenesis

Geriatric oncology health services research: Cancer and Aging Research Group infrastructure core

Founded by the late Dr. Arti Hurria, the Cancer and Aging Research Group (CARG) is a collaborative, interdisciplinary team of investigators dedicated to improving the care of older adults with cancer through research, advocacy, and other scholarly initiatives.1 As part of the CARG National Institute on Aging R21/R33 infrastructure grant to harness the available expertise and prioritize the development of high-impact research, the Health Services Research (HSR) Core was developed to foster and advance HSR in geriatric oncology. The mission of the HSR Core is to support clinical investigators to design and conduct highquality HSR focused on older adults with cancer and their caregivers including patterns of care, comparative effectiveness, and care delivery. At the first R21/R33 conference held at City of Hope in October 2018, Dr. Harvey Jay Cohen (Chair, CARG Oversight Board and HSR Core) led the development of this Core. In this perspective paper, we present a review of HSR in geriatric oncology to build a foundation for the Core rationale; proposed Core function, workflow, policies, and procedures; anticipated interactions with other CARG Cores; and proposed plans for sustainabilit

Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+

We perform amplitude analyses of the decays $B^0 \to K^+K^-K^0_S$, $B^+ \rightarrow K^+K^-K^+$, and $B^+ \to K^0_S K^0_S K^+$, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately $470\times 10^6$ $B\bar{B}$ decays, collected with the BABAR detector at the PEP-II asymmetric-energy $B$ factory at the SLAC National Accelerator Laboratory. For $B^+ \to K^+K^-K^+$, we find a direct CP asymmetry in $B^+ \to \phi(1020)K^+$ of $A_{CP}= (12.8\pm 4.4 \pm 1.3)$, which differs from zero by $2.8 \sigma$. For $B^0 \to K^+K^-K^0_S$, we measure the CP-violating phase $\beta_{\rm eff} (\phi(1020)K^0_S) = (21\pm 6 \pm 2)^\circ$. For $B^+ \to K^0_S K^0_S K^+$, we measure an overall direct CP asymmetry of $A_{CP} = (4 ^{+4}_{-5} \pm 2)$. We also perform an angular-moment analysis of the three channels, and determine that the $f_X(1500)$ state can be described well by the sum of the resonances $f_0(1500)$, $f_2^{\prime}(1525)$, and $f_0(1710)$.Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree with published versio

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results