A Search for Coincident Neutrino Emission from Fast Radio Bursts with Seven Years of IceCube Cascade Events

This paper presents the results of a search for neutrinos that are spatially and temporally coincident with 22 unique, nonrepeating fast radio bursts (FRBs) and one repeating FRB (FRB 121102). FRBs are a rapidly growing class of Galactic and extragalactic astrophysical objects that are considered a potential source of high-energy neutrinos. The IceCube Neutrino Observatory\u27s previous FRB analyses have solely used track events. This search utilizes seven years of IceCube cascade events which are statistically independent of track events. This event selection allows probing of a longer range of extended timescales due to the low background rate. No statistically significant clustering of neutrinos was observed. Upper limits are set on the time-integrated neutrino flux emitted by FRBs for a range of extended time windows

Singlet-to-triplet conversion of metastable He atoms at alkali-metal overlayers

Energy distributions of electrons emitted from alkali-metal surfaces by impact of metastable He atoms reveal that there is a high probability for transformation of singlet atoms (excitation energy E*=20.6 eV) into triplet atoms (E*=19.8 eV) prior to deexcitation into the ground state. The conversion probability (as expressed by the ratio R of the intensities of valence-band emission due to triplet and singlet He* deexcitation, respectively) increases with increasing alkali-metal coverage on a Ru(0001) substrate, and in turn decreases with increasing oxygen exposure at a fixed alkali coverage. These findings indicate that R is a qualitative measure for the degree of \u2018\u2018metallization\u2019\u2019 of the adlayer. R also increases with temperature due to broadening of the nearest-neighbor distribution whereby, on the average, a larger part of the adlayer becomes metalliclike. For Cs overlayers exhibiting work functions <2 eV the mechanism of deexcitation changes and may proceed via He*- (1s12s2) formation as reflected by the R data as well as by the widths of the electron spectra

O- escape during the oxidation of cesium

Exposure of Cs surfaces to O2 causes ejection of O- ions with low yields ( 3c10-8 per incident O2 molecule) during the first stages of dissociative chemisorption (followed by exoelectron emission at higher exposures), although the work function of the surface exceeds the electron affinity of O and the energetics of the overall reaction is almost zero. A mechanism is proposed whereafter the release of O- is a consequence of strong repulsion in O22- species intermediately formed in front of the surface

Exoelectron emission during the oxidation of Na films

Oxidation of Na films is accompanied by a low yield of electron emission which is, however, confined to the later stages of reaction in which transformation of peroxide (Na2O2) into Superoxide (NaO2) species at the surface takes place. By probing the electronic properties of the outermost layer by means of metastable deexcitation spectroscopy (MDS) and by recording the energy distribution of the emitted exoelectrons the mechanism of this process was found to be analogous to that established previously for the oxidation of Cs films and as proposed earlier theoretically. It involves decay of a hole state derived from the affinity level of the impinging O2 molecule in front of the surface via an Auger transition which, on the other hand, may efficiently be quenched by resonance ionisation from metallic electrons near the Fermi level. Experiments with Na submonolayers adsorbed on a Ru(0001) substrate reveal that for coverages < 0.6 ML the latter effect dominates so strongly that exoelectron emission is no longer observed

Exoelectron emission at Cs surfaces by accelerated O2 molecules

The exoemission in the reaction of O-2 with Cs surfaces is found to depend strongly on the translational energy of the impinging O-2 molecules. Seeded beam experiments show that in the initial oxidation state exoemission increases with increasing O-2 velocity. Above 0.5 eV of kinetic energy the increase is found to be proportional to exp(-v*/v) with a value v* of 1.6 x 10(4) m/s

Plato argénteo nº 38.215 . Reverso - ABE0155_AR

Proyectos del Plan Nacional I+D+I con referencias PB94-0129, PB97-1132, BHA 2002-00138, HUM 2006-06250/HISTProyectos de la CAM con referencias 06/0020/1997, 06/0094/1998, 06/0090/2000, 06/0043/2001Programa Consolider-Ingenio 2010 con sigla CSD2007-00058NoMuseo Arqueológico Nacional (Madrid)AbengibrePlato argénteo nº 38.215 . Revers

Status and Future of Biomass Assessment for Energetic Use in Europe

Results from biomass potential assessments vary considerably, both on global and European level. On the other hand reliable figures on biomass potentials are an important basis for energy policy and for strategies that aim at an increase of use of biomass for energy both on EU-Level as well as e. g. on national level in the National Renewable Energy Action Plans (NREAPs) by the 27 member states. This paper is based on the findings of two projects, BEE and CEUBIOM. It presents an overview of the findings of these projects and includes an analysis of biomass potential aspects within the NREAPs. It presents how, based on an analysis of the status quo of potential studies, the projects developed proposals for a harmonisation of the methodologies and it presents the key areas they identified for future work in the field

Status and Future of Biomass Assessment for Energetic Use in Europe

Results from biomass potential assessments vary considerably, both on global and European level. On the other hand reliable figures on biomass potentials are an important basis for energy policy and for strategies that aim at an increase of use of biomass for energy both on EU-Level as well as e. g. on national level in the National Renewable Energy Action Plans (NREAPs) by the 27 member states. This paper is based on the findings of two projects, BEE and CEUBIOM. It presents an overview of the findings of these projects and includes an analysis of biomass potential aspects within the NREAPs. It presents how, based on an analysis of the status quo of potential studies, the projects developed proposals for a harmonisation of the methodologies and it presents the key areas they identified for future work in the field