Spectral analysis of the high-energy IceCube neutrinos

A full energy and flavor-dependent analysis of the three-year high-energy IceCube neutrino events is presented. By means of multidimensional fits, we derive the current preferred values of the high-energy neutrino flavor ratios, the normalization and spectral index of the astrophysical fluxes, and the expected atmospheric background events, including a prompt component. A crucial assumption resides on the choice of the energy interval used for the analyses, which significantly biases the results. When restricting ourselves to the ~30 TeV - 3 PeV energy range, which contains all the observed IceCube events, we find that the inclusion of the spectral information improves the fit to the canonical flavor composition at Earth, (1:1:1), with respect to a single-energy bin analysis. Increasing both the minimum and the maximum deposited energies has dramatic effects on the reconstructed flavor ratios as well as on the spectral index. Imposing a higher threshold of 60 TeV yields a slightly harder spectrum by allowing a larger muon neutrino component, since above this energy most atmospheric tracklike events are effectively removed. Extending the high-energy cutoff to fully cover the Glashow resonance region leads to a softer spectrum and a preference for tau neutrino dominance, as none of the expected electron antineutrino induced showers have been observed so far. The lack of showers at energies above 2 PeV may point to a broken power-law neutrino spectrum. Future data may confirm or falsify whether or not the recently discovered high-energy neutrino fluxes and the long-standing detected cosmic rays have a common origin.Comment: 33 pages, 13 figures. v3: one extra figure (fig. 13), some references updated and some formulae moved to the Appendix. It matches version published in PR

A fractal fragmentation model for rockfalls

The final publication is available at Springer via http://dx.doi.org/10.1007/s10346-016-0773-8The impact-induced rock mass fragmentation in a rockfall is analyzed by comparing the in situ block size distribution (IBSD) of the rock mass detached from the cliff face and the resultant rockfall block size distribution (RBSD) of the rockfall fragments on the slope. The analysis of several inventoried rockfall events suggests that the volumes of the rockfall fragments can be characterized by a power law distribution. We propose the application of a three-parameter rockfall fractal fragmentation model (RFFM) for the transformation of the IBSD into the RBSD. A discrete fracture network model is used to simulate the discontinuity pattern of the detached rock mass and to generate the IBSD. Each block of the IBSD of the detached rock mass is an initiator. A survival rate is included to express the proportion of the unbroken blocks after the impact on the ground surface. The model was calibrated using the volume distribution of a rockfall event in Vilanova de Banat in the Cadí Sierra, Eastern Pyrenees, Spain. The RBSD was obtained directly in the field, by measuring the rock block fragments deposited on the slope. The IBSD and the RBSD were fitted by exponential and power law functions, respectively. The results show that the proposed fractal model can successfully generate the RBSD from the IBSD and indicate the model parameter values for the case study.Peer ReviewedPostprint (author's final draft

Promoter trap analysis of the light signaling circuitry in Arabidopsis thaliana

Light is one of the most environmental factors that control plant growth and development. Research concerning the effect of light quality and light intensity has focused on the photoreceptors that perceive the light signals, the genetics of photoreceptor-specific signaling pathways, and the developmental responses to light. However little is known about the integration of signals from the various light signaling pathways. Light signaling pathways and their interactions were investigated in Arabidopsis thaliana by measuring light responsive transcription in a collection of promoter trap lines. Each promoter trap line carries a single, transposon-mediated fusion between a randomly selected endogenous Arabidopsis sequence and the E. coli β-glucuronidase (GUS) reporter gene. Light response profiles, defined as the variation in GUS expression of a gene over a range of environmental conditions, were characterized for a large number of individual promoter traps by histochemical GUS straining and by whole-plant enzyme assays. By applying either constant light or darkness or shifts between light and darkness, I identified 286 light responsive promoter traps. Interestingly, a large fraction of the lines screened displayed tissue-specific light responsiveness. Few examples of this phenomenon have been published based on transgenic promoter:reporter fusions in plants. The light responsive lines were screened for their response under constant red, constant far-red light, and four types of light pulse regimes in order to define the relative sensitivity of the lines to phytochrome A (phyA) and phytochrome B (phyB) photoreceptors. All tissues surveyed, including the root, were capable of supporting a variety of light response profiles, suggesting that the interaction between light signaling pathways are similarly complex in most cell types. It was very rare to find stronger expression in constant far red than constant red light. This finding suggests that the phyA pathway, active under constant far red, plays a major role in the regulation of genes that are repressed by light and a minor role in genes that are active by light. Because certain light response profiles occurred repeatedly, it was possibly to group the profiles using hierarchical cluster analysis. This revealed groups of genes with antagonistic or synergistic interactions between phyA and phyB. The chromosomal flanking sequences that drive the light responsive expression profiles were analyzed in detail for fifteen promoter traps. The typical light responsive promoter trap was light repressible, yet contained basal promoter sequence motifs, as well as motifs previously implicated in light inducible gene expression. Many of the light responsive flanking sequences were bona fide cryptic promoters, rather than regulatory regions for native Arabidopsis genes, indicating that cryptic promoters may play an important role in the light-signaling network. Microarray analyses of individual Arabidopsis cDNAs in response to shifts between light and darkness were performed as a first step to correlate expression profiles identified by promoter trapping with profiles defined at the level of mRNAs. For both light shift experiments, the most commonly activated genes coded for proteins involved in metabolism, and among these, primary metabolism outweighed secondary metabolism. After the shift from constant dark to light, inducible genes preferentially coded for proteins involved in photosynthetic light reactions. In contrast, a shift from light to darkness elicited the expression of genes involved in cell expansion and transport, as expected. More unexpectedly, the shift to darkness also triggered expression of genes involved in translation and stress responses

Performance assessment of a radio access network augmented with user equipment enabled with relaying capabilities

This Master's Thesis is encompassed in a vision of a Beyond 5G (B5G) scenario, where the User Equipment is exploited not only to satisfy the specific needs of the user, but also to augment the Radio Access Network (RAN) infrastructure. The research work has consisted in studying and analysing the deployment of a network using UEs as relaying devices in order to achieve an augmented RAN that will be able to offer a better performance to the users, including higher spectral efficiency, and lower outage probability. The conducted studies have consisted in performing variations on the configuration parameters of the network, as well as characterising the relay nodes, by means of simulations. The obtained results have then been analysed, evaluating them in terms of spectral efficiency and outage probability, and a specific relay activation strategy has been proposed, which has proven to introduce improvements in the network performance

Warm dark matter and the ionization history of the Universe

In warm dark matter scenarios structure formation is suppressed on small scales with respect to the cold dark matter case, reducing the number of low-mass halos and the fraction of ionized gas at high redshifts and thus, delaying reionization. This has an impact on the ionization history of the Universe and measurements of the optical depth to reionization, of the evolution of the global fraction of ionized gas and of the thermal history of the intergalactic medium, can be used to set constraints on the mass of the dark matter particle. However, the suppression of the fraction of ionized medium in these scenarios can be partly compensated by varying other parameters, as the ionization efficiency or the minimum mass for which halos can host star-forming galaxies. Here we use different data sets regarding the ionization and thermal histories of the Universe and, taking into account the degeneracies from several astrophysical parameters, we obtain a lower bound on the mass of thermal warm dark matter candidates of $m_X > 1.3$ keV, or $m_s > 5.5$ keV for the case of sterile neutrinos non-resonantly produced in the early Universe, both at 90\% confidence level.Comment: 15 pages, 5 figure

Protein Expression of Steroid Receptors in Macaca mulatta endometriotic Lesions

Endometriosis is pathologically defined as the presence of endometrial tissue in ectopic locations. Currently, there are no specific, non-invasive biomarkers and no cure for endometriosis. Non-human primates (NHP), including Macaca mulatta (rhesus macaques), have been highlighted as appropriate models to study endometriosis due to genetic, physiological, and anatomical similarities to humans. Research shows endometriosis might be associated with molecular deviations in human peritoneal endometriosis, such as increased levels of estrogen receptors and decreased levels of progesterone receptors. The aim of this study is to determine protein expression of steroid receptors in five endometriotic lesions of rhesus macaques. We propose that lesions of rhesus macaques will express elevated estrogen receptors and diminished progesterone receptors, similar to human endometriotic lesions. Endometriotic lesions of rhesus macaques were obtained at time of surgery from different locations, and steroid receptor expression was determined by immunohistochemistry. This study was able to determine the expression of steroid receptors in endometriotic lesions of rhesus macaques; however the results were not able to support our hypothesis. Results did not observe significant differences between estrogen and progesterone receptor protein expressions in glandular and stromal compartments of the endometriotic lesions. Still, this animal model represents a valuable tool to study endometriosis since they do develop spontaneous endometriosis. Future studies should match the location of lesions and classify the severity of endometriosis in the rhesus macaques