Deexcitation nuclear gamma-ray line emission from low-energy cosmic rays in the inner Galaxy

Recent observations of high ionization rates of molecular hydrogen in diffuse interstellar clouds point to a distinct low-energy cosmic-ray component. Supposing that this component is made of nuclei, two models for the origin of such particles are explored and low-energy cosmic-ray spectra are calculated which, added to the standard cosmic ray spectra, produce the observed ionization rates. The clearest evidence of the presence of such low-energy nuclei between a few MeV per nucleon and several hundred MeV per nucleon in the interstellar medium would be a detection of nuclear \gamma-ray line emission in the range E_ 0.1 - 10 MeV, which is strongly produced in their collisions with the interstellar gas and dust. Using a recent \gamma-ray cross section compilation for nuclear collisions, \gamma-ray line emission spectra are calculated alongside with the high-energy \gamma-ray emission due to {\pi} 0 decay, the latter providing normalization of the absolute fluxes by comparison with Fermi-LAT observations of the diffuse emission above E \gamma = 0.1 GeV. Our predicted fluxes of strong nuclear \gamma-ray lines from the inner Galaxy are well below the detection sensitivies of INTEGRAL, but a detection, especially of the 4.4-MeV line, seems possible with new-generation \gamma-ray telescopes based on available technology. We predict also strong \gamma-ray continuum emission in the 1-8 MeV range, which in a large part of our model space for low-energy cosmic rays exceeds considerably estimated instrument sensitivities of future telescopes.Comment: 22 pages, 7 figures, accepted for publication in ApJ; figures 6 and 7 replace

Comparison of Leishmania killicki (syn. L-tropica) and Leishmania tropica population structure in Maghreb by microsatellite typing

Leishmania (L.) killicki (syn. L. tropica), which causes cutaneous leishmaniasis in Maghreb, was recently described in this region and identified as a subpopulation of L. tropica. The present genetic analysis was conducted to explore the spatio-temporal distribution of L. killicki (syn. L. tropica) and its transmission dynamics. To better understand the evolution of this parasite, its population structure was then compared with that of L. tropica populations from Morocco. In total 198 samples including 85 L. killicki (syn. L. tropica) (from Tunisia, Algeria and Libya) and 113 L. tropica specimens (all from Morocco) were tested. Theses samples were composed of 168 Leishmania strains isolated from human skin lesions, 27 DNA samples from human skin lesion biopsies, two DNA samples from Ctenodactylus gundi bone marrow and one DNA sample from a Phlebotomus sergenti female. The sample was analyzed by using MultiLocus Enzyme Electrophoresis (MLEE) and MultiLocus Microsatellite Typing (MLMT) approaches. Analysis of the MLMT data support the hypothesis that L. killicki (syn. L. tropica) belongs to the L. tropica complex, despite its strong genetic differentiation, and that it emerged from this taxon by a founder effect. Moreover, it revealed a strong structuring in L. killicki (syn. L. tropica) between Tunisia and Algeria and within the different Tunisian regions, suggesting low dispersion of L. killicki (syn. L. tropica) in space and time. Comparison of the L. tropica (exclusively from Morocco) and L. killicki (syn. L. tropica) population structures revealed distinct genetic organizations, reflecting different epidemiological cycles

Flavonoid glycosides from Periploca laevigata (Asclepiadaceae) from Algeria

The phytochemical investigation of the n-butanol extract of aerial parts of Periploca laevigata resulted in the isolation of four known compounds, kaempferol 3-O-β-arabinopyranoside (1), kaempferol 3-O-β-glucopyranoside (2), quercetin 3-O-arabinopyranoside (3) and quercetin 3-O-rutinoside (4).The structures of the compounds were determined on the basis of extensive spectroscopic analysis, including 1D and 2D NMR as well as acid hydrolysis and comparison with the related known compounds

Measurement and analysis of nuclear γ-ray production cross sections in proton interactions with Mg, Si, and Fe nuclei abundant in astrophysical sites over the incident energy range E = 30–66 MeV

The modeling of nuclear γ -ray line emission induced by highly accelerated particles in astrophysical sites (e.g., solar flares, the gas and dust in the inner galaxy) and the comparison with observed emissions from these sites needs a comprehensive database of related production cross sections. The most important reactions of protons and α particles are those with abundant target elements like C, O, N, Ne, Mg, Si, and Fe at projectile energies extending from the reaction threshold to a few hundred MeV per nucleon. In this work, we have measured γ -ray production cross section excitation functions for 30, 42, 54, and 66 MeV proton beams accelerated onto nat C , C + O (Mylar), nat Mg , nat Si , and 56 Fe targets of astrophysical interest at the Separated Sector Cyclotron (SSC) of iThemba LABS (near Cape Town, South Africa). The AFRODITE array equipped with eight Compton suppressed high-purity (HPGe) clover detectors was used to record γ -ray line energy spectra. For known, intense lines previously reported experimental data measured up to E p ≃ 25 MeV at the Washington and Orsay tandem accelerators were thus extended to higher proton energies. Our experimental data for the last three targets are reported here and discussed with respect to previous data and to the Murphy et al. compilation [Astrophys. J. Suppl. Ser. 183, 142 (2009)]

Determination of the central density on the basis of its moments

The value of the central density is of key importance for annihilation processes. For the ground state we discuss its determination from the moments of the ground state density. We first review the way of reaching the moments from the spectrum. In particular we show how to get the lowest moments in D = 3, namely Ær 2æ and Ær 1æ from the series expansion of the Laplace transform of the density. We then recall a method to obtain the central density based on the Stieltjes moment problem. If the number of known moments is finite, this technique yields a lower bound. We investigate the possibilities to estimate the accuracy of the bound and the corresponding asymptotic value. An application to the muonic 208Pb atom is presente

Nuclear γ-ray line emission induced by energetic ions in solar flares and by galactic cosmic rays

International audienceThe γ-ray spectra ol the strongest solar flares often show a broad and complex structure in the 0.1-10 MeV region sitting on a bremsstrahlung continuum. This structure is composed of several outstanding narrow lines and of thousands of unresolved narrow and broad lines forming a quasi-continuum. The major part of this emission is due to prompt deexcitation lines following nuclear interactions of accelerated light and heavy ions with the atomic nuclei composing the solar atmosphere. A similar emission is expected from interactions of galactic cosmic rays with the interstellar gas and dust. Experimental nuclear reaction studies coupled with extensive calculations have been done in the last one and a half decade at Orsay for the modelisation of this γ-ray emission. After a description of the nuclear reaction studies the analysis of one solar flare spectrum and predictions for the emission from the inner Galaxy will be presented

Use of PCR, IFAT and in vitro

The aim of this study was to assess the use of parasitological, serological and molecular methods for the detection of Leishmania infection in blood of 67 dogs and to investigate the prevalence of canine leishmaniasis (CanL) in Kairouan (central Tunisia), an area known to be of reduced endemicity and has not been studied since 1973. Veterinarians clinically examined all dogs, and the titer of anti-Leishmania antibodies was determined by indirect immune-fluorescence antibody test. The presence of Leishmania was performed by PCR and in vitro culture. IFAT was positive in 12% of dogs and promastigote form of the parasite was isolated by in vitro culture from only 4.5% of them. However, DNA of Leishmania was detected by PCR in 20.9% of dogs. PCR was more sensitive than IFAT (p = 0.004) and in vitro culture (p < 10–5). A prevalence of 21% was found in Kairouan, which is significant high (p < 10–3) when compared to that of thirty years ago. This state is in correlation with the increase in other Mediterranean countries. Furthermore, 50% of positive dogs were asymptomatic. Preventive measures must be taken against these dogs as for symptomatic ones since their role in the transmission of the infection to vectors has been proven