Composite boson dominance in relativistic field theories

We apply a new bosonization technique to relativistic field theories of fermions whose partition function is dominated by bosonic composites, and derive the effective action for these bosons. The derivation respects all symmetries, including gauge invariance, with the exception of Euclidean invariance which must be checked a posteriori. We use a lattice regularization which should make applications to gauge theories easier. We test the method on a fermion field theory with quartic interaction in the limit when the number of flavours N_f is large, and show that it reproduces the exact results in the bosonic sector, namely condensation of a compositeboson with the right mass which breaks the discrete chiral invariance of the model. Moreover we determine the structure function of the condensed composite, whose spatial part turns out to be identical to that of the Cooper pairs of the BCS model of superconductivity

Status and perspectives of 2ε, εβ+ and 2β+ decays

This paper reviews the main experimental techniques and the most significant results in the searches for the 2ε, εβ+ and 2β+ decay modes. Efforts related to the study of these decay modes are important, since they can potentially offer complementary information with respect to the cases of 2β− decays, which allow a better constraint of models for the nuclear structure calculations. Some positive results that have been claimed will be mentioned, and some new perspectives will be addressed shortly

Lattice energy-momentum tensor with Symanzik improved actions

We define the energy-momentum tensor on lattice for the $\lambda \phi^4$ and for the nonlinear $\sigma$-model Symanzik tree-improved actions, using Ward identities or an explicit matching procedure. The resulting operators give the correct one loop scale anomaly, and in the case of the sigma model they can have applications in Monte Carlo simulations.Comment: Self extracting archive fil

Strong Earthquakes in North-Western Africa in the Second Half of the 17th Century, AD: A Critical Reappraisal of the Historical Evidence

The recent seismological literature recorded three strong earthquakes in Algeria, Libya and Tunisia between 1656 and 1694 AD. The historical evidence for these derives from European sources only (gazettes, journalistic pamphlets, missionary literature). Considering the kind of sources involved, their likely biases and the geographical distances that divided their places of production from the places that they spoke about, it is possible that some of these accounts could be less than reliable, and therefore have little use as materials from which to assess earthquake parameters. To answer these doubts, we have retrieved, cross-checked and critically analysed the original historical sources quoted in previous compilations and studies

Modelling the shrub encroachment in a grassland with a Cellular Automata Model

Abstract. Arid and semi-arid grasslands of southwestern North America have changed dramatically over the last 150 years as a result of shrub encroachment, i.e. the increase in density, cover and biomass of indigenous shrubby plants in grasslands. Numerous studies have documented the expansion of shrublands in the southwestern American grasslands; in particular shrub encroachment has occurred strongly in part of the northern Chihuahuan desert since 1860. This encroachment has been simulated using an ecohydrological Cellular Automata model, CATGraSS. It is a spatially distributed model driven by spatially explicit irradiance and runs on a fine-resolution gridded domain. Plant competition is modelled by keeping track of mortality and establishment of plants; both are calculated probabilistically based on soil moisture stress. For this study CATGraSS has been improved with a stochastic fire module and a grazing function. The model has been implemented in a small area in Sevilleta National Wildlife Refuge (SNWR), characterized by two vegetation types (grass savanna and creosote bush shrub), considering as encroachment causes the fire return period increase, the grazing increase, the seed dispersal caused by animals, the role of wind direction and plant type competition. The model is able to reproduce the encroachment that has occurred in SNWR, simulating an increase of the shrub from 2% in 1860 to the current shrub percentage, 42%, and highlighting among the most influential factors the reduced fire frequency and the increased grazing intensity

Assessing the benefits of Andean crop diversity on farmers' livelihood: insights from a development programme in Bolivia and Peru

This paper analyses the impact of a development programme designed at promoting the sustainable use of Andean Grain diversity. Results demonstrate that knowledge-sharing on agronomic practices, on benefits derived from consumption, and improving Andean Grain quality had a positive impact on income generation and farmer livelihoods. These results demonstrate the effectiveness of programmes aimed at improving rural livelihoods through greater knowledge transfer and use of local agrobiodiversity, wherein private benefits may incentivise the public benefits of agrobiodiversity use and conservation. Findings warrant the need to further monitor and evaluate the potential of agrobiodiversity to improve the well-being of rural communities

The 1561 Earthquake(s) in Southern Italy: New Insights into a Complex Seismic Sequence

In the summer of 1561, a strong seismic sequence struck southern Italy, then the Spanish-ruled Kingdom of Naples. Both the Italian seismological tradition and the latest catalogues locate it in the Vallo di Diano (Diano Valley), a low-seismicity intermontane basin 100 km south-east of Naples. We explore the hypothesis that current perception of the 1561 earthquake is distorted by the nature of the historical dataset from which its parameters have been assessed, and which mostly derive from a single—albeit very detailed—primary source. We present and discuss several previously unconsidered original accounts. Our results cast doubts on the traditional interpretation of the earthquake, which could have been either one Vallo di Diano mainshock or several strong earthquakes within a time/space window compact enough for contemporary viewers to perceive them as one. Unquestionably, there is much more to the 1561 earthquake(s) than previously appeared. We hope that this groundbreaking effort will rekindle the interest of the seismological community in this seismic episode, our knowledge of which is still far from complete

Investigation of rare nuclear decays with BaF2_2 crystal scintillator contaminated by radium

The radioactive contamination of a BaF$_2$ scintillation crystal with mass of 1.714 kg was measured over 101 hours in the low-background DAMA/R&D set-up deep underground (3600 m w.e.) at the Gran Sasso National Laboratories of INFN (LNGS, Italy). The half-life of $^{212}$Po (present in the crystal scintillator due to contamination by radium) was measured as $T_{1/2}(^{212}$Po) = 298.8$\pm$0.8(stat.)$\pm$1.4(syst.) ns by analysis of the events' pulse profiles. The $^{222}$Rn nuclide is known as 100% decaying via emission of $\alpha$ particle with $T_{1/2}$ = 3.82 d; however, its $\beta$ decay is also energetically allowed with $Q_\beta = 24\pm21$ keV. Search for decay chains of events with specific pulse shapes characteristic for $\alpha$ or for $\beta/\gamma$ signals and with known energies and time differences allowed us to set, for the first time, the limit on the branching ratio of $^{222}$Rn relatively to $\beta$ decay as $B_\beta < 0.13$% at 90% C.L. (equivalent to limit on partial half-life $T_{1/2}^\beta > 8.0$ y). Half-life limits of $^{212}$Pb, $^{222}$Rn and $^{226}$Ra relatively to $2\beta$ decays are also improved in comparison with the earlier results.Comment: 10 pages, 9 figures, 2 table

Destruction of a protected habitat by an invasive alien species: the case of Cydalima perspectalis (Walker, 1859) in the box tree formations of Liguria (North-West Italy) (Lepidoptera: Crambidae)

The box tree moth, Cydalima perspectalis (Walker, 1859), an invasive alien species of Asian origin associated with box trees, gained immediate attention in Europe due to the damage caused to ornamental stands and its rapid spread. However, its effects on natural box tree formations remained poorly investigated, especially in Southern Europe. In Liguria (North-West Italy), attacked xerotermophilous box tree formations on rocky substrate, a protected habitat (5110) after the Natura 2000 EU 92/43 Directive, seriously endangering its long-term survival. Since detection in 2013, this species defoliated almost the whole area covered by habitat 5110, until experiencing a population crash after depleting its only trophic resource. We present here the evolution of the invasion and the population dynamics of this invasive alien species in Liguria during the years 2016-2017