Photoproduction of the ω\omega meson on the proton at large momentum transfer

The differential cross section, $d\sigma/dt$ for $\omega$ meson exclusive photoproduction on the proton above the resonance region ($2.6<W<2.9$ GeV) was measured up to a momentum transfer $-t = 5$ GeV$^2$ using the CLAS detector at Jefferson Laboratory. The $\omega$ channel was identified by detecting a proton and $\pi^+$ in the final state and using the missing mass technique. While the low momentum transfer region shows the typical diffractive pattern expected from Pomeron and Reggeon exchange, at large $-t$ the differential cross section has a flat behavior. This feature can be explained by introducing quark interchange processes in addition to the QCD-inspired two-gluon exchange.Comment: 5 pages, 5 figure

Genetic and chemical comparison among Camelina sativa varieties

Camelina sativa (Camelina sativa L. Crantz.) belonging to the mustard family, typically contain about 40 % oil in the seeds, 90 % of which is made up of unsaturated fatty acids: about 30\u201340% fraction of alpha linolenic acid, 15\u201325% fraction of linoleic acid, 15% fraction of oleic acid and around 15% eicosenoic acid. Genetic studies of the genome of C. sativa suggest a polyploid structure being more probably a hexaploid species. In European countries and Russia, camelina was grown as an agricultural crop before the II World War; now the renewed interest on this crop is mainly due to the search for new sources of essential fatty acids, particularly n-3(omega-3) fatty acids to be used in human food and animal feed products. In this work we compared different varieties of camelina grown in different conditions: in experimental field, greenhouse and grow chamber. We characterized the genetic material by SSRs to assess the genetic diversity to assist future breeding programs. In particular we have set up a breeding program aimed at reducing the glucosinolate content in camelina seed because of its toxic effect when present at high levels in seeds used as feed. Glucosinolate are sulphur-containing glucosides, found mainly in Brassicaceae, involved in plant defense. In the last year these molecules have been studied also because of their activities as natural pesticides and their protective effects against cancer, heart disease and chronic inflammatory disease. We are now characterizing camelina seeds for glucosinolate content in order to develop a diagnostic marker based on the analytical determination of the sulfur isotopic signature (\uf06434S). Such a marker will allow to easily select genetic materials with different glucosinolate contents without the use of complex and expensive analytical techniques

Measurement of the atmospheric muon flux with the NEMO Phase-1 detector

The NEMO Collaboration installed and operated an underwater detector including prototypes of the critical elements of a possible underwater km3 neutrino telescope: a four-floor tower (called Mini-Tower) and a Junction Box. The detector was developed to test some of the main systems of the km3 detector, including the data transmission, the power distribution, the timing calibration and the acoustic positioning systems as well as to verify the capabilities of a single tridimensional detection structure to reconstruct muon tracks. We present results of the analysis of the data collected with the NEMO Mini-Tower. The position of photomultiplier tubes (PMTs) is determined through the acoustic position system. Signals detected with PMTs are used to reconstruct the tracks of atmospheric muons. The angular distribution of atmospheric muons was measured and results compared with Monte Carlo simulations.Comment: Astrop. Phys., accepte

A new multianodic large area photomultiplier to be used in underwater neutrino detectors

In this article we describe the properties of a new 10-in. hemispherical photomultiplier manufactured by Hamamatsu. The prototype has a segmented photocathode and four independent amplification stages. The photomultiplier is one of the main components of a newly designed direction-sensitive optical module to be employed in large-scale underwater neutrino telescopes. The R&D activity has been co-funded by the INFN and the KM3NeT Consortium. The prototype performance fully meets with the design specifications

Detection potential of the KM3NeT detector for high-energy neutrinos from the Fermi bubbles

A recent analysis of the Fermi Large Area Telescope data provided evidence for a high-intensity emission of high-energy gamma rays with a E 2 spectrum from two large areas, spanning 50 above and below the Galactic centre (the ‘‘Fermi bubbles’’). A hadronic mechanism was proposed for this gamma-ray emission making the Fermi bubbles promising source candidates of high-energy neutrino emission. In this work Monte Carlo simulations regarding the detectability of high-energy neutrinos from the Fermi bubbles with the future multi-km3 neutrino telescope KM3NeT in the Mediterranean Sea are presented. Under the hypothesis that the gamma-ray emission is completely due to hadronic processes, the results indicate that neutrinos from the bubbles could be discovered in about one year of operation, for a neutrino spectrum with a cutoff at 100 TeV and a detector with about 6 km3 of instrumented volume. The effect of a possible lower cutoff is also considered.Published7–141.8. Osservazioni di geofisica ambientaleJCR Journalrestricte

Expansion cone for the 3-inch PMTs of the KM3NeT optical modules

[EN] Detection of high-energy neutrinos from distant astrophysical sources will open a new window on the Universe. The detection principle exploits the measurement of Cherenkov light emitted by charged particles resulting from neutrino interactions in the matter containing the telescope. A novel multi-PMT digital optical module (DOM) was developed to contain 31 3-inch photomultiplier tubes (PMTs). In order to maximize the detector sensitivity, each PMT will be surrounded by an expansion cone which collects photons that would otherwise miss the photocathode. Results for various angles of incidence with respect to the PMT surface indicate an increase in collection efficiency by 30% on average for angles up to 45 degrees with respect to the perpendicular. Ray-tracing calculations could reproduce the measurements, allowing to estimate an increase in the overall photocathode sensitivity, integrated over all angles of incidence, by 27% (for a single PMT). Prototype DOMs, being built by the KM3NeT consortium, will be equipped with these expansion cones.This work is supported through the EU, FP6 Contract no. 011937, FP7 grant agreement no. 212252, and the Dutch Ministry of Education, Culture and Science.Adrián Martínez, S.; Ageron, M.; Aguilar, JA.; Aharonian, F.; Aiello, S.; Albert, A.; Alexandri, M.... (2013). Expansion cone for the 3-inch PMTs of the KM3NeT optical modules. Journal of Instrumentation. 8(3):1-19. https://doi.org/10.1088/1748-0221/8/03/T03006S1198

A new instrument prototype for aerosol light absorption measurements

The prototype for an innovative instrument has been built and validated at the Department of Physics, University of Genoa. The purpose of the instrument is to measure the light absorption properties of atmospheric aerosol sampled on a filtering support, over a wide spectral range with a high wavelength resolution. The preliminary tests of the prototype have been carried out on aerosol produced in an atmospheric simulation chamber. The performance of the prototype has been validated against the previously assessed Multi Wavelength Absorbance Analyzer (MWAA), with a scatter plot slope of A = 0.95 ± 0.03, and a coefficient of determination of R2 = 0.97. Preliminary results show the data analysis possibilities that an instrument with a high spectral resolution can offer

Phlobaphenes modify pericarp thickness in maize and accumulation of the fumonisin mycotoxins

Phlobaphenes are insoluble phenolic compounds which are accumulated in a limited number of tissues such as seed pericarp and cob glumes, conferring on them a typical red-brown pigmentation. These secondary metabolites, derived from 3-deoxy flavonoids, are thought to have an important role in plants\u2019 resistance against various pathogens, e.g. by reducing fungal infection, and also to have beneficial effects on human and animal health due to their high antioxidant power. The aim of this work was to determine the role of phlobaphenes in reducing mycotoxin contamination on maize kernels. We analysed the effect of the P1 (pericarp color 1) gene on phlobaphenes accumulation, pericarp thickness and fumonisins accumulation. Analysing fumonisins accumulation in different genetic backgrounds through three seasons, we found a clear decrease of these toxins through the three years (Wilcoxon test, Z = 2.2, p = 0.0277) in coloured lines compared with the isogenic non-coloured ones. The coloured lines, carrying P1 allele showed an increase of phlobaphenes (about 10\u201314 fold) with respect to colourless lines. Furthermore there was a correlation between phlobaphenes accumulation and pericarp thickness (R = 0.9318; p = 0.0067). Taken together, these results suggest that the P1 gene plays a central role in regulating phlobaphenes accumulation in maize kernels, and indirectly, also tackles mycotoxins accumulation. The development and cultivation of corn varieties rich in phlobaphenes could be a powerful tool to reduce the loss of both quality and yield due to mycotoxin contamination, increasing the safety and the quality of the maize product

A new instrument prototype for aerosol light absorption measurements

The prototype for an innovative instrument has been built and validated at the Department of Physics, University of Genoa. The purpose of the instrument is to measure the light absorption properties of atmospheric aerosol sampled on a filtering support, over a wide spectral range with a high wavelength resolution. The preliminary tests of the prototype have been carried out on aerosol produced in an atmospheric simulation chamber. The performance of the prototype has been validated against the previously assessed Multi Wavelength Absorbance Analyzer (MWAA), with a scatter plot slope of A = 0.95 ± 0.03, and a coefficient of determination of R2 = 0.97. Preliminary results show the data analysis possibilities that an instrument with a high spectral resolution can offer