Revealing the short-range structure of the mirror nuclei 3H and 3He.

When protons and neutrons (nucleons) are bound into atomic nuclei, they are close enough to feel significant attraction, or repulsion, from the strong, short-distance part of the nucleon-nucleon interaction. These strong interactions lead to hard collisions between nucleons, generating pairs of highly energetic nucleons referred to as short-range correlations (SRCs). SRCs are an important but relatively poorly understood part of nuclear structure1-3, and mapping out the strength and the isospin structure (neutron-proton (np) versus proton-proton (pp) pairs) of these virtual excitations is thus critical input for modelling a range of nuclear, particle and astrophysics measurements3-5. Two-nucleon knockout or 'triple coincidence' reactions have been used to measure the relative contribution of np-SRCs and pp-SRCs by knocking out a proton from the SRC and detecting its partner nucleon (proton or neutron). These measurements6-8 have shown that SRCs are almost exclusively np pairs, but they had limited statistics and required large model-dependent final-state interaction corrections. Here we report on measurements using inclusive scattering from the mirror nuclei hydrogen-3 and helium-3 to extract the np/pp ratio of SRCs in systems with a mass number of three. We obtain a measure of the np/pp SRC ratio that is an order of magnitude more precise than previous experiments, and find a marked deviation from the near-total np dominance observed in heavy nuclei. This result implies an unexpected structure in the high-momentum wavefunction for hydrogen-3 and helium-3. Understanding these results will improve our understanding of the short-range part of the nucleon-nucleon interaction.

Novel Measurement of the Neutron Magnetic Form Factor from A=3 Mirror Nuclei.

The electromagnetic form factors of the proton and neutron encode information on the spatial structure of their charge and magnetization distributions. While measurements of the proton are relatively straightforward, the lack of a free neutron target makes measurements of the neutron's electromagnetic structure more challenging and more sensitive to experimental or model-dependent uncertainties. Various experiments have attempted to extract the neutron form factors from scattering from the neutron in deuterium, with different techniques providing different, and sometimes large, systematic uncertainties. We present results from a novel measurement of the neutron magnetic form factor using quasielastic scattering from the mirror nuclei ^{3}H and ^{3}He, where the nuclear effects are larger than for deuterium but expected to largely cancel in the cross-section ratios. We extracted values of the neutron magnetic form factor for low-to-modest momentum transfer, 0.6

Evidence of a Near-Threshold Resonance in

A narrow near-threshold proton-emitting resonance (E_{x}=11.4 MeV, J^{π}=1/2^{+}, and Γ_{p}=4.4 keV) was directly observed in ^{11}B via proton resonance scattering. This resonance was previously inferred in the ß-delayed proton emission of the neutron halo nucleus ^{11}Be. The good agreement between both experimental results serves as a ground to confirm the existence of such exotic decay and the particular behavior of weakly bound nuclei coupled to the continuum. R-matrix analysis shows a sizable partial decay width for both, proton and α (Γ_{α}=11 keV) emission channels.

[Psychological effects of emergency calls management on medical dispatcher assistants in a SAMU-Center 15]. / Répercussions psychologiques de la prise en charge des appels d'urgence sur les assistants de régulation médicale (ARM) d'un SAMU­Centre 15.

INTRODUCTION: In France, the emergency call center is called SAMU (service d'aide médicale d'urgence). The Medical Dispatcher Assistant (MDA) is the first responder and is exposed to first calls of distress and has a high risk of stress disorder. AIM: Psychological impact of emergency calls on MDA. METHOD: National multicenter prospective study from January to August 2018 by electronic surveys, including all MDA of 13 SAMU, subdivided in 5 sections: population characteristics, PCL-5 scale (DSM-5) assessing post-traumatic stress disorder (PTSD), ProQOL assessing professional quality of life, call categories and an MDA's emotional perception, and work impacts on an MDA's quality of life. Univariate descriptive statistical analysis of the group with PCL-5≥34 (=complete PTSD group) and with PCL-5<34 (=group without complete PTSD). RESULTS: Of 400 MDA asked to be interviewed, 283 (71 %) replied of whom 72 % (205) were women and 28 % (79) men. Age groups: 9 % (25) for 18-25 yrs, 39 % (110) for 26-35 yrs, 31 % (89) 36-45 yrs, 15 % (43) 46-55 yrs and 6 % (16) for more than 56 yrs. All MDA reported having been exposed to death experience. For 46 % (129) the most recent traumatic event occurred within the last 7 months. 78 % (219) have reported intense fear, feeling helpless, or even sensed horror when answering the calls. 97 % (273) could talk about it with colleagues but only 64 % (180) with family. 72 % (203) felt lack of recognition at work. 78 % (220) had no knowledge about psycho-traumatic disorder. While 11 % (30) suffered symptoms suggestive of a complete PTSD, 15 % (42) an incomplete PTSD, 3 % (8) suffer burnout and 4 % (11) compassion fatigue, none reported secondary traumatic stress. The only significant difference (P<0.05) between the two groups characteristics was on the education level. 74 % (22) of the MDA with a complete PTSD had a High School diploma or less. MDA with symptoms suggestive of complete PTSD developed significantly (P<0.001) more stress reduction strategies (alcohol, drugs, medication) (13 % vs 2 %), had more food disorders (80.5 % vs 38 %), more sleeping problems (75.5 % vs 21 %), more anxiety (67 % vs 17 %), and more sick leaves (13 % vs 4 %) than the group without complete PTSD. CONCLUSION: Part of the surveyed MDAs showed symptoms suggestive of PTSD. The study highlights that MDAs is a vulnerable population, and PTSD prevention techniques should be systematically implemented for them. The study also highlights that a higher education level prevents the psycho traumatic process with its accompanying disorders.

Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies.

The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-Z target. Positron polarization up to 82% have been measured for an initial electron beam momentum of 8.19 MeV/c, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.

Observation of the (Λ)(7)He hypernucleus by the (e, e'K+) reaction.

An experiment with a newly developed high-resolution kaon spectrometer and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab. The ground state of a neutron-rich hypernucleus, (Λ)(7)He, was observed for the first time with the (e, e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The (Λ)(7)He binding energy supplies the last missing information of the A = 7, T = 1 hypernuclear isotriplet, providing a new input for the charge symmetry breaking effect of the ΛN potential.

Comparison of GEANT4 very low energy cross section models with experimental data in water.

PURPOSE: The GEANT4 general-purpose Monte Carlo simulation toolkit is able to simulate physical interaction processes of electrons, hydrogen and helium atoms with charge states (H0, H+) and (He0, He+, He2+), respectively, in liquid water, the main component of biological systems, down to the electron volt regime and the submicrometer scale, providing GEANT4 users with the so-called "GEANT4-DNA" physics models suitable for microdosimetry simulation applications. The corresponding software has been recently re-engineered in order to provide GEANT4 users with a coherent and unique approach to the simulation of electromagnetic interactions within the GEANT4 toolkit framework (since GEANT4 version 9.3 beta). This work presents a quantitative comparison of these physics models with a collection of experimental data in water collected from the literature. METHODS: An evaluation of the closeness between the total and differential cross section models available in the GEANT4 toolkit for microdosimetry and experimental reference data is performed using a dedicated statistical toolkit that includes the Kolmogorov-Smirnov statistical test. The authors used experimental data acquired in water vapor as direct measurements in the liquid phase are not yet available in the literature. Comparisons with several recommendations are also presented. RESULTS: The authors have assessed the compatibility of experimental data with GEANT4 microdosimetry models by means of quantitative methods. The results show that microdosimetric measurements in liquid water are necessary to assess quantitatively the validity of the software implementation for the liquid water phase. Nevertheless, a comparison with existing experimental data in water vapor provides a qualitative appreciation of the plausibility of the simulation models. The existing reference data themselves should undergo a critical interpretation and selection, as some of the series exhibit significant deviations from each other. CONCLUSIONS: The GEANT4-DNA physics models available in the GEANT4 toolkit have been compared in this article to available experimental data in the water vapor phase as well as to several published recommendations on the mass stopping power. These models represent a first step in the extension of the GEANT4 Monte Carlo toolkit to the simulation of biological effects of ionizing radiation.

Hepatitis B, C seroprevalence and delta viruses in HIV-1 Senegalese patients at HAART initiation (retrospective study).

The aim of this study was to determine hepatitis co-infection in a cohort of HIV infected patients at their inclusion in the Senegalese Initiative of ART Access. B, C, and D Hepatitis viruses serological markers were checked retrospectively on 363 stored plasma. For HBV, the Abbott laboratories equipment IMx was used to detect HBs Ag and anti Core Ab on negative HBs Ag samples. For HDV, anti Delta Ab was performed using the Abbott Murex Kit on all HBs Ag positive samples. For HCV, anti HCV Ab was detected by IMx as double screening test and confirmed by INNO-LIA(TM) HCV Core of Innogenetics laboratories. The statistical analysis was done with STATA V8. The study population was composed of 164 men and 199 women aged between 16 and 66 years. The immune and virological markers averages at their enrollment were 154 cell/mm(3) for TLCD4+ (n = 355 patients) and 4.9 log for viral load (n = 277 patients). HBs Ag was found in 61 patients or 16.8% and the prevalence of anti-HBc Ab was 83.2% (252/295). 2 patients or 3% on HBs Ag positive sample presents HBV/HDV co-infection Ab anti HCV was detects in 6 patients or 1.6% after confirmation and 2 patients had triple infection with HBV. These results showed that the prevalence of HBV and HCV in the population of persons living with HIV/AIDS in Senegal is similar to that found in the general population. Our data indicated that hepatitis pathology in the PLwHIV was essentially due to HBV. Further studies are needed to diagnose occult hepatitis in order to set up therapeutic strategies taking into account co-infections by hepatitis viruses in the ART programmes.

Strengthening human genetics research in Africa: report of the 9th meeting of the African Society of Human Genetics in Dakar in May 2016.

The 9th meeting of the African Society of Human Genetics, in partnership with the Senegalese Cancer Research and Study Group and the Human Heredity and Health in Africa (H3Africa) Consortium, was held in Dakar, Senegal. The theme was Strengthening Human Genetics Research in Africa. The 210 delegates came from 21 African countries and from France, Switzerland, UK, UAE, Canada and the USA. The goal was to highlight genetic and genomic science across the African continent with the ultimate goal of improving the health of Africans and those across the globe, and to promote the careers of young African scientists in the field. A session on the sustainability of genomic research in Africa brought to light innovative and practical approaches to supporting research in resource-limited settings and the importance of promoting genetics in academic, research funding, governmental and private sectors. This meeting led to the formation of the Senegalese Society for Human Genetics.

Le 9ème congrès de la Société Africaine de Génétique Humaine, en partenariat avec le Groupe d'Etude et de Recherche sur le Cancer (GERC) et le Consortium H3Africa, s'est tenu à Dakar, au Sénégal. Le thème était «Renforcer la recherche en Génétique Humaine en Afrique¼. Les 210 participants sont venus de 21 pays africains et de six non africains. L'objectif était de valoriser la génétique et la génomique à travers l'Afrique avec comme but ultime d'améliorer la santé des populations, et de promouvoir les carrières des jeunes chercheurs Africains. Une session sur la pérennité de la recherche génomique a révélé des approches innovantes et pratiques supportant la recherche dans des contextes de ressources limitées et l'importance de promouvoir la formation universitaire en génétique, le financement de la recherche par les gouvernements et le privé. Ce congrès conduisit à la création de la Société Sénégalaise de Génétique Humaine.

Identification of all HIV type 1 group M subtypes in Senegal, a country with low and stable seroprevalence.

A total of 343 HIV-1-positive samples obtained between June 1996 and March 1999 was genetically characterized in the envelope region by HMA and/or sequencing. The env subtype distribution was as follows: 290 (84.6%) A, 22 (6.5%) B, 16 (4.7%) C, 8 (2.5%) D, 1 (0.03%) E, 1 (0.03%) F1, 4 (1.2%) G, and 1 (0.03%) H. For 77 samples the p24 region from the gag gene was also sequenced, and for 9 (11.6%) the subtypes between env and gag were different. Phylogenetic tree analysis showed the predominance of AG-IBNG-like viruses among gag and env subtype A sequences. HMA is relatively simple and requires less sophisticated technical facilities compared with sequencing, and in Senegal 323 (94.2%) of the 343 samples could be identified by this technique. However, in the actual configuration of the assay, discrimination between the recombinant AG-IBNG-like recombinant viruses, which are predominant in Senegal, and the nonrecombinant subtype A viruses is not possible.