NA60+ is a fixed target experiment proposed in the framework of the Physics Beyond Colliders programme at CERN. It aims to precisely measure the hard and electromagnetic probes in nuclear collisions. ...Initially proposed for the underground cavern ECN3 with very high beam intensities, the experiment now foresees a location in the EHN1 surface hall which was shown to have a limited impact on the physics performance in spite of a significant reduction of beam intensity and detector size. The potential installation and operation of the experiment with the ion beams from the Super Proton Synchrotron (SPS) has been examined regarding detector integration, beam physics, radiation protection and shielding requirements. The integration of the experiment is considered feasible, but would require a significant reconfiguration of the existing hall infrastructure with regards to shielding and layout.
KEY MESSAGE : Combining biparental and multiparental connected population analyses was useful for the identification of 11 QTLs in two new genetic backgrounds of carrot resistance to Alternaria dauci ...and for breeding recommendations. Leaf blight due to the fungus Alternaria dauci is the major carrot foliar disease worldwide. Some resistance QTLs have been previously identified in one population, but the evaluation of additional genetic backgrounds with higher level of resistance would give opportunities for breeders to combine them by pyramiding. For this purpose, two segregating populations were evaluated twice across 4 years in the same environment (1) to compare the efficiency of the single vs. the connected populations approach for characterizing the new sources of carrot resistance to Alternaria dauci; (2) to evaluate the stability of QTLs over the years; and (3) to give recommendations to breeders for marker-assisted selection. Single and connected analyses were complementary; their combination allowed the detection of 11 QTLs. Connected analyses allowed the identification of common and specific QTLs among the two populations and the most favorable allele at each QTL. Important contrasts between allelic effects were observed with four and five most favorable alleles coming from the two resistant parental lines, whereas two other favorable alleles came from the susceptible parental line. While four QTLs were consistent across years, seven were detected within a single year. The heritabilities for both populations PC2 and PC3 were high (75 and 78 %, respectively), suggesting that the resistance of carrot to A. dauci was little affected by these environmental conditions, but the instability of QTL over years may be due to changing environmental conditions. The complementarity between these parental lines in terms of interesting allelic combinations is also discussed.
We present a novel optimization approach to improve the convergence of interstation coda correlation functions towards the medium's empirical Green's function. For two stations recording a series of ...impulsive events in a multiply scattering medium, we explore the impact of coda window selection through a Markov Chain Monte Carlo scheme, with the aim of generating a gather of correlation functions that is the most coherent and symmetric over events, thus recovering intuitive elements of the interstation Green's function without any nonlinear post-processing techniques. This approach is tested here for a 2-D acoustic finite difference model, where a much improved correlation function is obtained, as well as for a database of small impulsive icequakes recorded on Erebus Volcano, Antarctica, where similar robust results are shown. The average coda solutions, as deduced from the posterior probability distributions of the optimization, are further representative of the scattering strength of the medium, with stronger scattering resulting in a slightly delayed overall coda sampling. The recovery of singly scattered arrivals in the coda of correlation functions are also shown to be possible through this approach, and surface wave reflections from outer craters on Erebus volcano were mapped in this fashion. We also note that, due to the improvement of correlation functions over subsequent events, this approach can further be used to improve the resolution of passive temporal monitoring.
To quantify genetic diversity among modern and earlier maize cultivars, 133 varieties, representative of the maize grown in France during the last five decades, were fingerprinted using 51 SSR. The ...varieties were grouped into four periods. For each period, allelic richness, genetic diversity and genetic differentiation among periods were computed. A total of 239 alleles were generated. Allelic richness, in terms of number of alleles per locus, for each period was 4.5, 3.6, 3.9 and 3.6 respectively. Genetic diversity corresponding to Nei's unbiased heterozygosity was calculated, based on allelic frequencies. Values ranged from 0.56 to 0.61. Period I presented the highest genetic diversity, whereas the three other periods all presented a similar value. A great proportion of the total genetic diversity (H(T)=0.59) was conserved within all periods (H(S)=0.57), rather than among periods (G(ST)=0.04). The analysis of molecular variance showed that the variation among periods represented only 10% of the total molecular variation. However, the differentiation among periods, although low, was significant, except for the last two periods. Our results showed that the genetic diversity has been reduced by about 10% in the maize cultivars bred before 1976 compared to those bred after 1985. The very low differentiation (G(ST)=0.21%) observed among cultivars of the last two decades should alert French maize breeders to enlarge genetic basis in their variety breeding programmes.
Horizontal and polygenic resistance is race-nonspecific and, therefore, more durable, unlike vertical resistance, which is race-specific and unstable. However, this division is perhaps not so obvious ...since some cultivar × isolate interactions have already been observed for plant species with partial resistance. Carrot is known to be partially resistant to
Alternaria dauci
, but it is relevant for breeders to study cultivar × isolate interactions in order to develop durable resistant varieties. For this purpose, 12 highly diverse carrot genotypes and one segregating population were inoculated in a tunnel or in a glass house with 11 isolates of
A. dauci
that also represented a high diversity in terms of geographical origin, aggressiveness and genetic diversity. Disease severity values were assessed three times in the tunnel in a one-year experiment (2002) and twice in the glass house in an experiment over two consecutive years (2011 and 2012). The interaction of isolate with genotype was non-significant in the tunnel, and the same result was obtained in the glasshouse for both years of study except for the first scoring date in 2011, suggesting that the partial resistance of carrot to
A. dauci
is probably mainly explained by major QTLs that confer resistance to a large number of isolates and, potentially, some minor isolate-specific QTLs as well.
The aggressiveness of Alternaria dauci isolates was investigated in greenhouse conditions. Twenty‐seven isolates were pre‐selected from a large collection to represent high diversity according to ...geographic or host origins and intergenic spacer (IGS) polymorphism. IGS sequence analysis revealed that isolates were grouped within three different clusters. Eleven isolates were selected and inoculated on a susceptible carrot cultivar. Three criteria (mean lesion number, mean necrotic leaf area and mean disease index) were used to assess the aggressiveness of isolates. Continuous variation in aggressiveness was shown and no clear division into isolate classes was evident. For the host range study, two isolates were inoculated under greenhouse conditions onto nine cultivated Apiaceae species, two wild Daucus species and six cultivated non‐Apiaceae species representing six botanical families. Lesions varying in severity were observed on all dicot species (Apiaceae and non‐Apiaceae), but no symptoms developed on the two monocots studied (leek and sweetcorn). Plant species were also differentiated on the basis of expanding lesions (cultivated and wild carrot, dill and fennel) or non‐expanding lesions (other dicot species). Typical A. dauci conidia were observed after in vitro incubation of leaves with symptoms. Fungal structures were isolated from lesions and A. dauci was confirmed on the basis of conidial morphology and specific conventional PCR results. Genotyping of individual isolates performed with microsatellite markers confirmed the presence of the inoculated isolate. The results clearly showed that, in controlled conditions, the host range of A. dauci is not restricted to carrot.
A new parasitic, mixed-field, neutron-dominated irradiation station has been recently commissioned at the European Laboratory for Particle Physics (CERN). The station is installed within the neutron ...time-of-flight (n_TOF) facility, taking advantage of the secondary radiation produced by the neutron spallation target, with neutrons ranging from 0.025 eV to several hundreds of MeV. The new station allows radiation damage studies to be performed in irradiation conditions that are closer to the ones encountered during the operation of particle accelerators; the irradiation tests carried out in the station will be complementary to the standard tests on materials, usually performed with gamma sources. Samples will be exposed to neutron-dominated doses in the MGy range per year, with minimal impact on the n_TOF facility operation. The station has 24 irradiation positions, each hosting up to100cm3of sample material. In view of its proximity to the n_TOF target, inside protective shielding, the irradiation station and its operating procedures have been carefully developed taking into account the safety of personnel and to avoid any unwanted impact on the operation of the n_TOF facility and experiments. Due to the residual radioactivity of the whole area around the n_TOF target and of the irradiated samples, access to the irradiation station is forbidden to human operators even when the n_TOF facility is not in operation. Robots are used for the remote installation and retrieval of the samples, and other optimizations of the handling procedures were developed in compliance with radiation protection regulations and the aim of minimizing doses to personnel. The sample containers were designed to be radiation tolerant, compatible with remote handling, and subject to detailed risk analysis and testing during their development. The whole life cycle of the irradiated materials, including their post-irradiation examinations and final disposal, was considered and optimized.
Horizontal and polygenic resistance is race-nonspecific and, therefore, more durable, unlike vertical resistance, which is race-specific and unstable. However, this division is perhaps not so obvious ...since some cultivar x isolate interactions have already been observed for plant species with partial resistance. Carrot is known to be partially resistant to Alternaria dauci, but it is relevant for breeders to study cultivar x isolate interactions in order to develop durable resistant varieties. For this purpose, 12 highly diverse carrot genotypes and one segregating population were inoculated in a tunnel or in a glass house with 11 isolates of A. dauci that also represented a high diversity in terms of geographical origin, aggressiveness and genetic diversity. Disease severity values were assessed three times in the tunnel in a one-year experiment (2002) and twice in the glass house in an experiment over two consecutive years (2011 and 2012). The interaction of isolate with genotype was non-significant in the tunnel, and the same result was obtained in the glasshouse for both years of study except for the first scoring date in 2011, suggesting that the partial resistance of carrot to A. dauci is probably mainly explained by major QTLs that confer resistance to a large number of isolates and, potentially, some minor isolate-specific QTLs as well.
The aim of this study, led by the GEVES (Research and Control Group for Varieties and Seeds), was to suggest indicators to assess the diversity available to farmers since the French Official ...Catalogue for Plant Varieties and Species was initiated. The largest datasets of 1990 inbred maize lines and 578 pea lines from the last 50 years were analysed using morphological and enzymatic parameters. Lines were grouped into three to five periods. Genetic diversity was estimated in each period from morphological and enzymatic markers by computing numerous indices, such as the number of classes of scores for each characteristic, allelic richness or genetic diversity index (H e ). Population differentiation parameters (GST, GST', FST, QST) were also estimated between periods. While genetic diversity computed from distinction, uniformity, stability traits was more marked for maize (0.66) than for garden peas (0.35) or feed peas (0.29), the opposite trend was observed with enzymes, resulting in a genetic diversity of 0.43, 0.35 and 0.22 for garden peas, feed peas and maize, respectively. However, no significant changes in genetic diversity were observed over time, and genetic differentiation was slight between periods. All our results demonstrated that no significant reduction in the diversity available to farmers had been observed since initiation of the French Catalogue. The H e was a good indicator providing a quantitative estimate of genetic diversity, but it should be interpreted alongside a more precise indicator such as allelic richness or the number of classes for morphological characteristics.
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