LUNA: Status and Prospects

The essential ingredients of nuclear astrophysics are the thermonuclear reactions which shape the life and death of stars and which are responsible for the synthesis of the chemical elements in the Universe. Deep underground in the Gran Sasso Laboratory the cross sections of the key reactions responsible for the hydrogen burning in stars have been measured with two accelerators of 50 and 400 kV voltage right down to the energies of astrophysical interest. As a matter of fact, the main advantage of the underground laboratory is the reduction of the background. Such a reduction has allowed, for the first time, to measure relevant cross sections at the Gamow energy. The qualifying features of underground nuclear astrophysics are exhaustively reviewed before discussing the current LUNA program which is mainly devoted to the study of the Big-Bang nucleosynthesis and of the synthesis of the light elements in AGB stars and classical novae. The main results obtained during the study of reactions relevant to the Sun are also reviewed and their influence on our understanding of the properties of the neutrino, of the Sun and of the Universe itself is discussed. Finally, the future of LUNA during the next decade is outlined. It will be mainly focused on the study of the nuclear burning stages after hydrogen burning: helium and carbon burning. All this will be accomplished thanks to a new 3.5 MV accelerator able to deliver high current beams of proton, helium and carbon which will start running under Gran Sasso in 2019. In particular, we will discuss the first phase of the scientific case of the 3.5 MV accelerator focused on the study of $^{12}$C+$^{12}$C and of the two reactions which generate free neutrons inside stars: $^{13}$C($\alpha$,n)$^{16}$O and $^{22}$Ne($\alpha$,n)$^{25}$Mg.Comment: To be published in Progress in Particle and Nuclear Physics 98C (2018) pp. 55-8

Reconstruction multipliers

A law issued to allocate reconstruction grants following the 2009 "Aquilano" earthquake has resulted in a large and unanticipated discontinuity across municipalities with comparable damages. Using diff-in-diff analysis we estimate the "local spending" and the "local tax" multipliers--according to the composition of the stimulus--controlling for the negative supply shock generated by the event. The stimulus prevented a fall in economic activity and the multiplicative effects of tax cuts are estimated much higher than those of spending. Our results underline the importance of countercyclical fiscal interventions and suggest the most effective composition of such a stimulus

Shake me the money!

During a natural disaster, the negative supply shock due to the destruction of productive capacity is counteracted by a positive demand shock due to public grants for assistance and reconstruction positing an identification issue in empirical work. Focusing on the 2009 'Aquilano' earthquake in Italy as a case study, we take advantage of quantified measure of damages for 75,424 buildings to estimate the negative supply shock and of a law issued to allocate reconstruction grants, which resulted in a sharp, exogenous discontinuity in transfers and output behavior across neighboring municipalities to estimate the positive demand shock. Diff-in-diff analysis suggests that local output multipliers of reconstruction grants (net of marginal tax rebates) are below unity. Yet the size of the grants act as a public insurance scheme, preventing a fall in output

Positronium signature in organic liquid scintillators for neutrino experiments

Electron anti-neutrinos are commonly detected in liquid scintillator experiments via inverse beta decay, by looking at the coincidence between the reaction products, neutron and positron. Prior to positron annihilation, an electron-positron pair may form an orthopositronium (o-Ps) state, with a mean life of a few ns. Even if the o-Ps decay is speeded up by spin flip or pick off effects, it may introduce distortions in the photon emission time distribution, crucial for position reconstruction and pulse shape discrimination algorithms in anti-neutrino experiments. Reversing the problem, the o-Ps induced time distortion represents a new signature for tagging anti-neutrinos in liquid scintillator. In this paper, we report the results of measurements of the o-Ps formation probability and lifetime, for the most used solvents for organic liquid scintillators in neutrino physics (pseudocumene, linear alkyl benzene, phenylxylylethane, and dodecane). We characterize also a mixture of pseudocumene +1.5 g/l of 2,5-diphenyloxazole, a fluor acting as wavelength shifter. In the second part of the paper, we demonstrate that the o-Ps induced distortion of the scintillation photon emission time distributions represent an optimal signature for tagging positrons on an event by event basis, potentially enhancing the anti-neutrino detection.Comment: 6 pages, 9 figure

Consumer Spending and Fiscal Consolidation: Evidence from a Housing Tax Experiment

A major change of the property tax system in 2011 generated significant variation in the amount of housing taxes paid by Italian households. Using new questions added to the Survey on Household Income and Wealth (SHIW), we exploit this variation to provide an unprecedented analysis of the effects of property taxes on consumer spending. A tax on the main dwelling leads to large expenditure cuts among households with mortgage debt and low liquid wealth but generates only small revenues for the government. In contrast, higher tax rates on other residential properties reduce private savings and yield large tax revenues

The Impact of Earthquakes on Economic Activity: Evidence from Italy

Although earthquakes are large idiosyncratic shocks for affected regions, little is known of their impact on economic activity. Seismic events are rare, the data is crude (the Richter scale measures the magnitude but says nothing of the associated damages) and counterfactuals are often entirely absent. We suggest an innovative identification strategy to address these issues based on the so-called ’Mercalli scale’ ranks - a geophysical methodology devised to gauge seismic damages relying on a newly compiled dataset following 95 Italian provinces from 1986 to 2011 (including 22 seismic episodes) offering an ideal ground for identification. Also, we carry out counterfactuals taking advantage of ex ante identical neighboring provinces that only differ ex post in terms of damages. Contrary to conventional views, we find that the impact of seismic events on output is negligible (or even positive) including after the most devastating events

Reconstruction multipliers

A law issued to allocate reconstruction grants following the 2009 "Aquilano" earthquake has resulted in a large and unanticipated discontinuity across municipalities with comparable damages. Using diff-in-diff analysis we estimate the "local spending" and the "local tax" multipliers--according to the composition of the stimulus--controlling for the negative supply shock generated by the event. The stimulus prevented a fall in economic activity and the multiplicative effects of tax cuts are estimated much higher than those of spending. Our results underline the importance of countercyclical fiscal interventions and suggest the most effective composition of such a stimulus

Evidence from the 2009 L’Aquila earthquake shows the importance of public grants in stimulating output following an economic shock

In 2009, an earthquake struck the region of Abruzzo in Italy near L’Aquila, causing over 300 deaths and substantial damage to buildings. Francesco Porcelli and Riccardo Trezzi present findings on the economic impact of the earthquake, particularly in terms of the role of reconstruction grants which were allocated to affected areas. They note that not every area which suffered damage by the earthquake was allocated funding and that these grants proved essential in stimulating economic output following the disaster. The findings provide evidence that interventions through public funding can be vital in enabling areas to recover following an economic shock

Sementes como fonte alternativa de substâncias químicas com atividade alelopática.

Na literatura mundial, observa-se predominância das folhas como meio preferencial de estudos de compostos químicos promissores, embora informações sobre outras frações da planta também sejam encontradas. Essa tendência se deve ao fato de que a maioria dos estudos mostra as folhas com atividade potencialmente alelopática de intensidade superior à das demais frações. Nesta revisão, procurou-se compilar e analisar as informações disponíveis sobre a importância das sementes como fonte alternativa de compostos químicos com atividade alelopática. São discutidas as variações na produção e na alocação de aleloquímicos em função do estádio ontogenético das sementes presentes no banco de sementes. É discutido também o papel dos aleloquímicos produzidos por sementes na repelência de insetos, na inibição do desenvolvimento de patógenos nas sementes, na inibição do desenvolvimento inicial de plantas daninhas e como sinalizador positivo para a simbiose com microrganismos do solo. Apresenta-se ainda a atividade alelopática de diversas substâncias isoladas de sementes, destacando-se os alcaloides, flavonoides, benzoxazinoides e resinas glicosídicas. Os estudos de aleloquímicos produzidos por sementes podem contribuir expressivamente para o melhor entendimento do papel ecológico que essas substâncias desempenham na ecologia química dos agro e ecossistemas

Densidade de plantas daninhas monocotiledôneas afetada por sistemas de manejo do solo e de adubação.

Nesse contexto, a hipótese desse trabalho é que o menor revolvimento do solo, manutenção de cobertura deste com palha e adubação podem reduzir a densidade de plantas daninhas monocotiledôneas durante os cultivos estivais ao longo do tempo. Assim, o objetivo dessa pesquisa foi avaliar a densidade de plantas daninhas monocotiledôneas emergidas no início do ciclo das culturas estivais, do sétimo ao décimo ano de aplicação de diferentes sistemas de manejo do solo associados a formas de adubação. Houve aumento da densidade de plantas daninhas monocotiledôneas com o incremento do distúrbio mecânico do solo e a retirada ou queima dos resíduos culturais, demonstrando a importância do sistema de plantio direto na redução da infestação dessas plantas. As formas de adubação não afetaram a densidade de plantas daninhas monocotiledôneas