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61.
SEARCH FOR NEUTRINOS AT EXTREME ENERGIES WITH THE PIERRE AUGER OBSERVATORY
Marta Trini, 2019, doctoral dissertation

Abstract: The detection of Ultra-High-Energy (UHE) neutrinos around and above 10 18 eV (1 EeV) can be the key to answering the long-standing question of the origin of the UHE cosmic rays. The Pierre Auger Observatory is the largest experiment that can detect the extensive air showers produced when the cosmic rays and neutrinos interact in the earth’s atmosphere. In particular, with the Infilled array of the Surface Detector of the Pierre Auger Observatory we can detect sub-EeV neutrino-induced particle showers. In this thesis we demonstrate that it is possible to discriminate neutrino-induced showers from the background showers produced by the more numerous nucleonic cosmic rays. The sensitivity to neutrinos is enhanced in the inclined directions with respect to the vertical to the ground, where cosmic ray-induced showers starting in the upper layers of the atmosphere are dominated by the muonic component of the shower, while deeply- penetrating neutrino showers in contrast exhibit a large electromagnetic component. Based on this idea in this thesis we have developed a search procedure for UHE neutrinos that consists on selecting inclined events in the Infilled array of the Pierre Auger Observatory in which the signals in the water-Cherenkov stations are spread in time, characteristic of the presence of electromagnetic component in the shower. We have established a complete chain of criteria to first select the inclined events among the sample of all events triggering the Infilled array, and then identifying those that have a large electromagnetic component at ground, and hence can be considered as neutrino candidates. We have identified a single variable, the so-called area-over-peak averaged over all of the stations in each event, as a suitable observable for neutrino identification purposes. The neutrino selection was established using extensive Monte Carlo simulations of the neutrino-induced showers in the Infilled array of Auger as well as a fraction of the data assumed to be totally constituted of background nucleonic cosmic rays. Using these neutrino simulations we have also computed the exposure of the Infilled array to UHE neutrinos in the period 1 January 04 - 31 December 2017. Associated systematic uncertainties on the exposure are also described. Expecting no candidate neutrinos in the period up to 31 December 2017, and adopting a differential neutrino diffuse flux dN ν /dE ν = k E ν −2 in the energy range from 0.05 to 1 EeV, we have obtained a 90% C.L. upper limit on the all neutrino flavor, k 90 < 7.97 × 10 −8 GeV cm −2 s −1 sr −1 .
Keywords: astroparticles, astrophysical neutrinos, cosmic rays showers, Pierre Auger Observatory, Infilled array
Published in RUNG: 03.10.2019; Views: 4852; Downloads: 147
.pdf Full text (6,02 MB)

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Analysis of 19 Minerals and Cortisol in Red Deer Hair in Two Different Areas of the Stelvio National Park: A Preliminary Study
Marta Montillo, Tanja Peric, 2019, original scientific article

Abstract: The aim of the study was to perform an investigation on the concentration of 19 minerals and cortisol in red deer (Cervus elaphus) hair, a matrix that is easy to collect with non-invasive and painless sampling, able to represent an integrative values of long-term substance concentrations, and able to give useful information, also when performed on dead animals, given its extreme stability over time. In the study thirty-five animals were included, coming from two different sides of a valley in the Stelvio National Park, where official water analysis had pointed out elevated concentrations of As in one of the two orographic sides. Hair cortisol concentrations were measured using a RIA(Radio Immuno Assay), while minerals were detected using ICP-MS (Inductively Coupled Plasma- Mass Spectrometry). Results showed a negative relationship between cortisol and some mineral concentrations (Li, Co, As, Cd, Cr and Tl) and significant differences in some mineral concentrations between park areas (Al, Co, Cu, Cd and Ni). As, Cr and cortisol differences approached statistical significance. This preliminary study represents a step forward in the study of wildlife allostatic load and a valid method for applications in wildlife management programs, in environmental studies and in public health programs.
Keywords: hair, deer, mineral, cortisol
Published in RUNG: 27.08.2019; Views: 2987; Downloads: 97
.pdf Full text (2,10 MB)

64.
TD/GC–MS analysis of volatile markers emitted from mono- and co-cultures of Enterobacter cloacae and Pseudomonas aeruginosa in artificial sputum
Iain R. White, Oluwasola Lawal, Hugo Knobel, Weda Hans, Tamara M E Nijsen, Royston Goodacre, Stephen J. Fowler, Waqar M Ahmed, Antonio Artigas, Jonathan Barnard-Smith, Lieuwe D Bos, Marta Camprubi, Luis Coelho, Paul Dark, Alan Davie, Emili Diaz, Gemma Goma, Timothy Felton, Jan H Leopold, Pouline M P van Oort, Pedro Póvoa, Craig Portsmouth, 2018, original scientific article

Abstract: Introduction: Infections such as ventilator-associated pneumonia (VAP) can be caused by one or more pathogens. Current methods for identifying these pathogenic microbes often require invasive sampling, and can be time consuming, due to the requirement for prolonged cultural enrichment along with selective and differential plating steps. This results in delays in diagnosis which in such critically ill patients can have potentially life-threatening consequences. Therefore, a non-invasive and timely diagnostic method is required. Detection of microbial volatile organic compounds (VOCs) in exhaled breath is proposed as an alternative method for identifying these pathogens and may distinguish between mono- and poly-microbial infections. Objectives: To investigate volatile metabolites that discriminate between bacterial mono- and co-cultures. Methods: VAP-associated pathogens Enterobacter cloacae and Pseudomonas aeruginosa were cultured individually and together in artificial sputum medium for 24 h and their headspace was analysed for potential discriminatory VOCs by thermal desorption gas chromatography–mass spectrometry. Results: Of the 70 VOCs putatively identified, 23 were found to significantly increase during bacterial culture (i.e. likely to be released during metabolism) and 13 decreased (i.e. likely consumed during metabolism). The other VOCs showed no transformation (similar concentrations observed as in the medium). Bacteria-specific VOCs including 2-methyl-1-propanol, 2-phenylethanol, and 3-methyl-1-butanol were observed in the headspace of axenic cultures of E. cloacae, and methyl 2-ethylhexanoate in the headspace of P. aeruginosa cultures which is novel to this investigation. Previously reported VOCs 1-undecene and pyrrole were also detected. The metabolites 2-methylbutyl acetate and methyl 2-methylbutyrate, which are reported to exhibit antimicrobial activity, were elevated in co-culture only. Conclusion: The observed VOCs were able to differentiate axenic and co-cultures. Validation of these markers in exhaled breath specimens could prove useful for timely pathogen identification and infection type diagnosis.
Keywords: Bacteria, Enterobacter cloacae, Gas Chromatography-Mass Spectrometry, Infection, Pseudomonas aeruginosa, Volatile organic compounds
Published in RUNG: 18.07.2019; Views: 4516; Downloads: 114
.pdf Full text (1,29 MB)

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Maternal and fetal hair cortisol concentrations in beef cattle at delivery
Tanja Peric, Monica Probo, Antonella Comin, Maria Cristina Veronesi, Marta Montillo, Alberto Prandi, 2018, published scientific conference contribution abstract

Abstract: Hypothalamus-pituitary-adrenal (HPA) axis of both mother and fetus, is one of key mechanisms involved in fetal programming. Cortisol, the end-product of this axis, plays a critical role in regulating fetal and new-born metabolism and development. The aim of the study was to evaluate maternal and fetal cortisol concentrations shortly after delivery on hair samples non-invasively collected. The study was carried out on 11 pairs of beef cows and their calves (calves were 12 because of one case of twins) from the same farm and subjected to the same managerial conditions. Hair from new-born calves and from their mothers was collected on the day of birth shaving their withers to the level of the skin. The hair cortisol concentrations (HCC) were determined by RIA as previously described (Peric et al. 2013: J Dairy Sci 96:3023–3027). The results showed that fetal and maternal HCC ranged from 16.11 to 40.43 pg/mg and from 1.88 to 15.73 pg/mg respectively, with fetal and maternal mean ± SE HCC of 23.72 ± 2.21 and 6.40 ± 1.32 pg/mg respectively (p < 0.001). Fetal HCC were on average 3.5 higher than those of mothers but this ratio differed among the pairs. These differences were also found among the twin calves. These results indicate that in beef cows-and-calves pairs, although HCC at delivery were always higher in calves than in cows, the ratio between fetal and maternal HCC differs among pairs, suggesting an individuality in the fetal programming processes that may also rely on genetic and epigenetic factors.
Keywords: hair, cortisol, cattle, delivery
Published in RUNG: 09.04.2019; Views: 3518; Downloads: 0
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67.
Ultra-high energy neutrinos searches with the Pierre Auger Observatory
Marta Trini, Danilo Zavrtanik, Danilo Zavrtanik, Serguei Vorobiov, Samo Stanič, Gašper Kukec-Mezek, Lukas Zehrer, 2019, published scientific conference contribution

Abstract: In the EeV range, neutrinos are expected to be produced by ultra-high energy cosmic rays interactions with the Cosmic Microwave Background during propagation in the Universe. We report on the search for ultra-high energy neutrinos in data collected with the Surface Detector of the Pierre Auger Observatory. The searches are most efficient in the zenith angle range from 60 degrees to 95 degrees with tau neutrinos skimming in the Earth playing dominant role. The present non-detection of UHE neutrinos in the Pierre Auger Observatory excludes the most optimistic scenarios of neutrino production in terms of UHE cosmic rays chemical composition and cosmological evolution of the acceleration sites. We also report on the searches for neutrinos in coincidence with the recent Gravitational Wave events detected by LIGO/Virgo.
Keywords: EeV neutrinos, Pierre Auger Observatory, limits
Published in RUNG: 26.02.2019; Views: 3811; Downloads: 0
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