Fiscal Policy Discretion, Private Spending, and Crisis Episodes

In this paper, we assess the impact of fiscal policy discretion on economic activity in the short and medium-term. Using a panel of 132 countries from 1960 to 2008, we find that fiscal policy discretion provides a net stimulus to the economy in the short-run and crowding-in effects are amplified once crisis episodes are controlled for– in particular, banking crises - giving a great scope for fiscal policy stimulus packages. However, crowding-out effects take over in the long-run – especially, in the case of debt crises -, in line with the concerns about long-term debt sustainability.Fiscal policy discretion, GDP growth, private consumption, private investment, crowding-in, crowding-out.

The relevance of point defects in studying silica-based materials from bulk to nanosystems

The macroscopic properties of silica can be modified by the presence of local microscopic modifications at the scale of the basic molecular units (point defects). Such defects can be generated during the production of glass, devices, or by the environments where the latter have to operate, impacting on the devices’ performance. For these reasons, the identification of defects, their generation processes, and the knowledge of their electrical and optical features are relevant for microelectronics and optoelectronics. The aim of this manuscript is to report some examples of how defects can be generated, how they can impact device performance, and how a defect species or a physical phenomenon that is a disadvantage in some fields can be used as an advantage in others

29Si Hyperfine Structure of the E'_\alpha Center in Amorphous Silicon Dioxide

We report a study by electron paramagnetic resonance (EPR) on the E'_\alpha point defect in amorphous silicon dioxide (a-SiO2). Our experiments were performed on gamma-ray irradiated oxygen-deficient materials and pointed out that the 29Si hyperfine structure of the E'_alpha consists in a pair of lines split by 49 mT. On the basis of the experimental results a microscopic model is proposed for the E'_alpha center, consisting in a hole trapped in an oxygen vacancy with the unpaired electron sp3 orbital pointing away from the vacancy in a back-projected configuration and interacting with an extra oxygen atom of the a-SiO2 matrix.Comment: 4 page

The A(Kstop−,π±Σ∓)A′A(K^-_{stop},\pi^\pm\Sigma^\mp)A' reaction on p-shell nuclei

This letter is concerned with the study of the $K^-_{stop}A\rightarrow \pi^\pm\Sigma^\mp A'$ reaction in p-shell nuclei, i.e., $^{6,7}Li$, $^9Be$, $^{13}C$ and $^{16}O$. The $\pi^\pm\Sigma^\mp / K^-_{stop}$ emission rates are reported as a function of $A$. These rates are discussed in comparison with previous findings. The ratio $\pi^-\Sigma^+/\pi^+\Sigma^-$ in p-shell nuclei is found to depart largely from that on hydrogen, which provides support for large in-medium effects possibly generated by the sub-threshold $\Lambda(1405)$. The continuum momentum spectra of prompt pions and free sigmas are also discussed as well as the $\pi^\pm\Sigma^\mp$ missing mass behavior and the link with the reaction mechanism. The apparatus used for the investigation is the FINUDA spectrometer operating at the DA$\Phi$NE $\phi$-factory (LNF-INFN, Italy).Comment: 14 pages, 5 figures, accepted for publication in Phys. Lett.

Fruit Pest Events and Phenological Development According to Accumulated Heat Units

Mammals are "warm-blooded" and develop at a constant rate regardless of the environmental temperature, because they are able to maintain an internal temperature that allows their biochemical reactions to progress normally. Insects, which are "exothermic" (the same temperature as their environment; there is no such thing as "cold-blooded"), do not generate body heat, and are therefore limited in their development to periods of favorable external temperature. Below a certain temperature, which varies among species, the insect's biochemical reactions cannot proceed, and development stops. This temperature is known as the insect's developmental threshold ordevelopmental base. By charting the ambient temperature, it is possible to keep track of insect development, which is directly proportional to the amount of time accumulated above the developmental threshold (up to some maximum not often reached during the season). We arbitrarily divide this time into heat units, or degree-days (DD)

Fiscal policy discretion, private spending and crises episodes

In this paper, we assess the impact of fiscal policy discretion on economic activity in the short and medium-term. Using a panel of 132 countries from 1960 to 2008, we find that fiscal policy discretion provides a net stimulus to the economy in the short-run and crowding-in effects are amplified once crisis episodes are controlled for\u2013 in particular, banking crises - giving a great scope for fiscal policy stimulus packages. However, crowding-out effects take over in the long-run \u2013 especially, in the case of debt crises -, in line with the concerns about long-term debt sustainability

Structural relaxation of E' gamma centers in amorphous silica

We report experimental evidence of the existence of two variants of the E' gamma centers induced in silica by gamma rays at room temperature. The two variants are distinguishable by the fine features of their line shapes in paramagnetic resonance spectra. These features suggest that the two E' gamma differ for their topology. We find a thermally induced interconversion between the centers with an activation energy of about 34 meV. Hints are also found for the existence of a structural configuration of minimum energy and of a metastable state.Comment: 4 pages, 2 figures, submitted to Phys. Rev. Let