High-Fidelity Simulations of Long-Term Beam-Beam Dynamics on GPUs

Future machines such as the Electron Ion Collider (MEIC), linac-ring machines (eRHIC) or LHeC are particularly sensitive to beam-beam effects. This is the limiting factor for long-term stability and high luminosity reach. The complexity of the non-linear dynamics makes it challenging to perform such simulations typically requiring millions of turns. Until recently, most of the methods have involved using linear approximations and/or tracking for a limited number of turns. We have developed a framework which exploits a massively parallel Graphical Processing Units (GPU) architecture to allow for tracking millions of turns in a sympletic way up to an arbitrary order. The code is called GHOST for GPU-accelerated High-Order Symplectic Tracking. As of now, there is no other code in existence that can accurately model the single-particle non-linear dynamics and the beam-beam effect at the same time for a large enough number of turns necessary to verify the long-term stability of a collider. Our approach relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for the beam-beam interaction

Health Links: Who Acts as a Source of Health Information in a Social Network?

Background: Members of a social network can influence the preventive health choices and cancer screening behaviors of other network members. Study Design: We conducted in-person interviews with 438 insured adults ages 40-70 in Massachusetts, Hawaii, and Georgia. We gathered information on social network communication regarding routine health topics and cancer screening. Participants reported whether family members and friends ask them for information or advice on health topics. Characteristics of each respondent’s social network were explored, including number of people with whom the participant has discussed colorectal cancer (CRC) screening. Participants were asked whether communication with social network members had ever led them to seek cancer screening. Principal Findings:80% of respondents in our group described themselves as a source of health information or advice for others in their social network (89% of women vs. 68% of men, p Conclusions: People who identified themselves as a source of health information within their social network were more likely to have discussed CRC screening with others and communicated with more people. Further study is necessary to understand the roles played by these individuals. As “health information ambassadors,” they may be effective targets for interventions that promote preventive screening

Long-Term Simulations of Beam-Beam Dynamics on GPUs

Future machines such as the electron-ion colliders (JLEIC), linac-ring machines (eRHIC) or LHeC are particularly sensitive to beam-beam effects. This is the limiting factor for long-term stability and high luminosity reach. The complexity of the non-linear dynamics makes it challenging to perform such simulations which require millions of turns. Until recently, most of the methods used linear approximations and/or tracking for a limited number of turns. We have developed a framework which exploits a massively parallel Graphical Processing Units (GPU) architecture to allow for tracking millions of turns in a sympletic way up to an arbitrary order and colliding them at each turn. The code is called GHOST for GPU-accelerated High-Order Symplectic Tracking. As of now, there is no other code in existence that can accurately model the single-particle non-linear dynamics and the beam-beam effect at the same time for a large enough number of turns required to verify the long-term stability of a collider. Our approach relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for the beam-beam interaction

Incidence of angioedema after initiation of angiotensin-converting enzyme inhibitors in adults with heart failure

Background: Angioedema, a potentially life-threatening adverse event associated with angiotensin-converting enzyme inhibitor (ACEI) use, occurs more often among Black patients than non-Black patients. Specific angioedema incidence rates (IRs) among heart failure (HF) patients initiating an ACEI are limited. Objectives: To provide estimates of angioedema incidence among HF patients initiating an ACEI, particularly among Black patients. Methods: We conducted a retrospective cohort study among adult (≥18 years) patients with HF who initiated ACEI use at 5 health care delivery systems within the Cardiovascular Research Network between July 2015 and May 2019. We required patients to have ≥12 months of continuous medical and prescription drug coverage and no ACEI dispensings in the 1 year before treatment initiation. Our primary outcome was serious angioedema, defined as a primary or secondary diagnosis of ICD-9 code 995.1 (‘Angioneurotic edema not elsewhere classified’) or ICD-10 codes in the T78.3 series (‘Angioneurotic edema’) during hospitalization. Our secondary out-come was ‘any angioedema’, which included serious angioedema and non-serious angioedema that was diagnosed in the outpatient setting. We followed patients from ACEI initiation until first angioedema diagnosis or a censoring event (treatment discontinuation, initiation of another renin-angiotensin-aldosterone system blocking agent, disenrollment, death, or end of 365-day follow-up or study). We calculated crude IRs and exact 95% confidence intervals (CI) for angioedema among HF patients initiating an ACEI. Results: We identified 14 ,241 ACEI users, of which 6,156 (43 .2%)were women and 2,105 (15%) were self-reported Black. Mean age was 70 ± 14 years. We observed 6 serious angioedema events overall (IR: 0.8/1,000 person-years (PYs), 95% CI: 0.3-1.7), with 2 events occurring among Black patients (IR: 1.8/1,000 PYs, 95%CI: 0.2-6.5) and 4 events among non-Black patients (IR: 0.6/1,000PYs, 95% CI: 0.2-1.5). We observed 43 angioedema events overall (IR: 5.4/1,000 PYs, 95% CI: 3.9-7.3), with 21 events occurring among Black patients (IR: 19/1,000 PYs, 95% CI: 11.8-29.1) and 22 events among non-Black patients (IR: 3.2/1,000 PYs, 95%CI: 2.0-4.9). Conclusions: Our estimate of angioedema incidence among HF patients who initiated an ACEI (5.4 events/1,000 PYs) is slightly higher than a previously published estimate (3.3/1,000 PYs) among a similarly-defined population identified through administrative claims data. Similar to prior reports, we found a higher incidence of angioedema, both serious and non-serious, among Black ACEI users than among non-black ACEI users

The association between health literacy and cancer-related attitudes, behaviors, and knowledge

Using a multidimensional assessment of health literacy (the Cancer Message Literacy Test-Listening, the Cancer Message Literacy Test-Reading, and the Lipkus Numeracy Scale), the authors assessed a stratified random sample of 1013 insured adults (40-70 years of age). The authors explored whether low health literacy across all 3 domains (n =111) was associated with sets of variables likely to affect engagement in cancer prevention and screening activities: (a) attitudes and behaviors relating to health care encounters and providers, (b) attitudes toward cancer and health, (c) knowledge of cancer screening tests, and (d) attitudes toward health related media and actual media use. Adults with low health literacy were more likely to report avoiding doctor\u27s visits, to have more fatalistic attitudes toward cancer, to be less accurate in identifying the purpose of cancer screening tests, and more likely to avoid information about diseases they did not have. Compared with other participants, those with lower health literacy were more likely to say that they would seek information about cancer prevention or screening from a health care professional and less likely to turn to the Internet first for such information. Those with lower health literacy reported reading on fewer days and using the computer on fewer days than did other participants. The authors assessed the association of low health literacy with colorectal cancer screening in an age-appropriate subgroup for which colorectal cancer screening is recommended. In these insured subjects receiving care in integrated health care delivery systems, those with low health literacy were less likely to be up to date on screening for colorectal cancer, but the difference was not statistically significant

Health Literacy and Cancer Prevention: It’s Not What You Say It’s What They Hear

Background: A growing body of literature documents the relationship between health literacy and important health behaviors and outcomes. Most research to date has focused on print literacy–few studies have examined literacy with respect to spoken information (“spoken health literacy”). We sought to examine the extent to which responses to physician advice about cancer prevention and screening were associated with spoken health literacy. Methods: Participants listened to 3 simulated physician-patient discussions addressing: 1) Prostate Specific Antigen (PSA) testing; 2) tamoxifen for breast cancer prevention; and 3) colorectal cancer (CRC) screening. The physician provided information on risks and benefits but did not endorse one course of action. Post-vignette questions assessed understanding and reactions to the physician’s advice. Participants had previously completed the Cancer Message Literacy Test-Listening (CMLT-L), a measure of spoken health literacy. Bivariate analyses examined the relationship between CMLT-L scores and comprehension, attitudes, and behavioral intentions. Results: Four hundred thirty-eight adults from 3 HMORN sites participated. Comprehension: Post-vignette comprehension scores were correlated with CMLT-L scores (r=0.62, p Discussion: The ability to understand spoken information is a critical component of health literacy. In this study, spoken health literacy influenced patients’ comprehension of, and reaction to spoken health information provided by a physician. The findings that participants scoring in the lowest quartile on the CMLT-L were more likely to respond favorably to physician advice on cancer prevention but were less likely to comprehend content of the vignettes, may indicate that physician mention of a prevention service is interpreted as endorsement of a prevention service in the absence of a full understanding of its risks and benefits

Search for a new gauge boson in the A′A' Experiment (APEX)

We present a search at Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling $\alpha'$ to electrons. Such a particle $A'$ can be produced in electron-nucleus fixed-target scattering and then decay to an $e^+e^-$ pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175--250 MeV, found no evidence for an $A'\to e^+e^-$ reaction, and set an upper limit of $\alpha'/\alpha \simeq 10^{-6}$. Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.Comment: 5 pages, 5 figures, references adde

Deeply Virtual Compton Scattering off the neutron

The present experiment exploits the interference between the Deeply Virtual Compton Scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D$({\vec e},e'\gamma)X$ cross section measured at $Q^2$=1.9 GeV$^2$ and $x_B$=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to $E_q$, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced.Comment: Published in Phys. Rev. Let

The E00-110 experiment in Jefferson Lab's Hall A: Deeply Virtual Compton Scattering off the Proton at 6 GeV

We present final results on the photon electroproduction ($\vec{e}p\rightarrow ep\gamma$) cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region from Jefferson Lab experiment E00-110. Results from an analysis of a subset of these data were published before, but the analysis has been improved which is described here at length, together with details on the experimental setup. Furthermore, additional data have been analyzed resulting in photon electroproduction cross sections at new kinematic settings, for a total of 588 experimental bins. Results of the $Q^2$- and $x_B$-dependences of both the helicity-dependent and helicity-independent cross sections are discussed. The $Q^2$-dependence illustrates the dominance of the twist-2 handbag amplitude in the kinematics of the experiment, as previously noted. Thanks to the excellent accuracy of this high luminosity experiment, it becomes clear that the unpolarized cross section shows a significant deviation from the Bethe-Heitler process in our kinematics, compatible with a large contribution from the leading twist-2 DVCS$^2$ term to the photon electroproduction cross section. The necessity to include higher-twist corrections in order to fully reproduce the shape of the data is also discussed. The DVCS cross sections in this paper represent the final set of experimental results from E00-110, superseding the previous publication.Comment: 48 pages, 32 figure