Étude expérimentale et théorique de la production de nuclides légers rapides dans les interactions proton-noyau à haute énergie

Nous donnons la description d'une expérience réalisée au CERN et concernant la production de 1H, 2H, 3H, 3He, 4He lors des interactions proton-noyau (12C, 27Al, 197Au) à des angles variés (30°, 45°, 75°, 105°). Nous présentons également une théorie thermodynamique permettant d'interpréter les résultats expérimentaux obtenus

Aharonov-Bohm spectral features and coherence lengths in carbon nanotubes

The electronic properties of carbon nanotubes are investigated in the presence of disorder and a magnetic field parallel or perpendicular to the nanotube axis. In the parallel field geometry, the $\phi_{0}(=hc/e)$-periodic metal-insulator transition (MIT) induced in metallic or semiconducting nanotubes is shown to be related to a chirality-dependent shifting of the energy of the van Hove singularities (VHSs). The effect of disorder on this magnetic field-related mechanism is considered with a discussion of mean free paths, localization lengths and magnetic dephasing rate in the context of recent experiments.Comment: 22 pages, 6 Postscript figures. submitted to Phys. Rev.

Enhancement of low-mass dileptons in heavy-ion collisions

Using a relativistic transport model for the expansion stage of S+Au collisions at 200 GeV/nucleon, we show that the recently observed enhancement of low-mass dileptons by the CERES collaboration can be explained by the decrease of vector meson masses in hot and dense hadronic matter.Comment: 12 pages, RevTeX, 3 figures available from [email protected]

Examining the Cascade of Participant Attrition in a Genomic Medicine Research Study: Barriers and Facilitators to Achieving Diversity

Background/Aims: Recent genomic medicine initiatives underscore the importance of including diverse participants in research. Considerable literature has identified barriers to and facilitators of increasing diversity, yet disparities in recruiting and retaining adequate numbers of participants from diverse groups continue to limit the generalizability of clinical genomic research. Methods: The North Carolina Clinical Genomic Evaluation by Next-gen Exome Sequencing study employed evidence-based strategies to enhance the participation of under-represented minority patients. In this study, we evaluate the impact of our efforts by systematically analyzing the "cascade" of attrition of participants throughout study interactions. Results: Although successful in recruiting a cohort that included ~30% non-Caucasian patients overall, the study still enrolled and retained a lower proportion of minorities compared to the pool of eligible patients who were nominated. We evaluated sociodemographic characteristics and related variables as potential factors associated with attrition throughout these phases of the study. Conclusions: These results suggest that varied approaches will be needed to increase participation in genomic medicine research. Our findings highlight factors to consider when developing strategies to address this critical need. Failing to include a broad range of populations in research studies will exacerbate existing disparities in the translation of genomic sequencing to medical care

Constraints on the Nucleon Strange Form Factors at Q^2 ~ 0.1 GeV^2

We report the most precise measurement to date of a parity-violating asymmetry in elastic electron-proton scattering. The measurement was carried out with a beam energy of 3.03 GeV and a scattering angle =6 degrees, with the result A_PV = -1.14 +/- 0.24 (stat) +/- 0.06 (syst) parts per million. From this we extract, at Q^2 = 0.099 GeV^2, the strange form factor combination G_E^s + 0.080 G_M^s = 0.030 +/- 0.025 (stat) +/- 0.006 (syst) +/- 0.012 (FF) where the first two errors are experimental and the last error is due to the uncertainty in the neutron electromagnetic form factor. This result significantly improves current knowledge of G_E^s and G_M^s at Q^2 ~0.1 GeV^2. A consistent picture emerges when several measurements at about the same Q^2 value are combined: G_E^s is consistent with zero while G_M^s prefers positive values though G_E^s=G_M^s=0 is compatible with the data at 95% C.L.Comment: minor wording changes for clarity, updated references, dropped one figure to improve focu

The who, what, and why of research participants' intentions to request a broad range of secondary findings in a diagnostic genomic sequencing study

Purpose: In a diagnostic exome sequencing study (the North Carolina Clinical Genomic Evaluation by Next-Generation Exome Sequencing project, NCGENES), we investigated adult patients' intentions to request six categories of secondary findings (SFs) with low or no medical actionability and correlates of their intentions. Methods: At enrollment, eligible participants (n = 152) completed measures assessing their sociodemographic, clinical, and literacy-related characteristics. Prior to and during an in-person diagnostic result disclosure visit, they received education about categories of SFs they could request. Immediately after receiving education at the visit, participants completed measures of intention to learn SFs, interest in each category, and anticipated regret for learning and not learning each category. Results: Seventy-eight percent of participants intended to learn at least some SFs. Logistic regressions examined their intention to learn any or all of these findings (versus none) and interest in each of the six individual categories (yes/no). Results revealed little association between intentions and sociodemographic, clinical, or literacy-related factors. Across outcomes, participants who anticipated regret for learning SFs reported weaker intention to learn them (odds ratios (ORs) from 0.47 to 0.71), and participants who anticipated regret for not learning these findings reported stronger intention to learn them (OR 1.61-2.22). Conclusion: Intentions to request SFs with low or no medical actionability may be strongly influenced by participants' desire to avoid regret

Knowledge gaps that hamper prevention and control of Mycobacterium avium subspecies paratuberculosis infection

In the last decades, many regional and country‐wide control programmes for Johne's disease (JD) were developed due to associated economic losses, or because of a possible association with Crohn's disease. These control programmes were often not successful, partly because management protocols were not followed, including the introduction of infected replacement cattle, because tests to identify infected animals were unreliable, and uptake by farmers was not high enough because of a perceived low return on investment. In the absence of a cure or effective commercial vaccines, control of JD is currently primarily based on herd management strategies to avoid infection of cattle and restrict within‐farm and farm‐to‐farm transmission. Although JD control programmes have been implemented in most developed countries, lessons learned from JD prevention and control programmes are underreported. Also, JD control programmes are typically evaluated in a limited number of herds and the duration of the study is less than 5 year, making it difficult to adequately assess the efficacy of control programmes. In this manuscript, we identify the most important gaps in knowledge hampering JD prevention and control programmes, including vaccination and diagnostics. Secondly, we discuss directions that research should take to address those knowledge gaps.http://wileyonlinelibrary.com/journal/tbed2019-05-01hj2018Veterinary Tropical Disease

Heavy Quarks and Heavy Quarkonia as Tests of Thermalization

We present here a brief summary of new results on heavy quarks and heavy quarkonia from the PHENIX experiment as presented at the "Quark Gluon Plasma Thermalization" Workshop in Vienna, Austria in August 2005, directly following the International Quark Matter Conference in Hungary.Comment: 8 pages, 5 figures, Quark Gluon Plasma Thermalization Workshop (Vienna August 2005) Proceeding