Noise Bubbles

We introduce noisy information into a standard present value stock price model. Agents receive a noisy signal about the structural shock driving future dividend variations. The resulting equilibrium stock price includes a transitory component —the “noise bubble”— which can be responsible for boom and bust episodes unrelated to economic fundamentals. We propose a non-standard VAR procedure to estimate the structural shock and the “noise” shock, their impulse response functions and the bubble component of stock prices. We apply such procedure to US data and find that noise explains a large fraction of stock price volatility. In particular the dot-com bubble is entirely explained by noise. On the contrary the stock price boom peaking in 2007 is not a bubble, whereas the following stock market crisis is largely due to negative noise shocks

Catalytic combustion of hydrocarbons over perovskites

The advantages and disadvantages of the catalysts so far employed or proposed for the low temperature catalytic combustion of hydrocarbons, in both static and mobile energy production devices, are discussed. Furthermore, a La0.9Ce0.1CoO3\ub1\u3b4 perovskite has been prepared by a recently proposed new flame-hydrolysis (FH) method. This proved a high surface area, thermally highly resistant catalyst. The partial substitution of Ce for La in such a cobaltite led to a relatively low suprafacial activity, but to a high bulk oxygen mobility, leading to high intrafacial activity for the catalytic flameless combustion of methane. The best operating conditions have been also found, for supporting the so prepared active phase, by dip-coating of a cordieritic honeycomb support, after deposition of an alumina primer. A very active and durable catalyst was so obtained, useful for practical application in the environmentally friendly low temperature combustion of methane

Sufficient Information in Structural VARs

We derive necessary and sufficient conditions under which a set of variables is informationally sufficient, i.e. contains enough information to estimate the structural shocks with a VAR model. Based on such conditions, we provide a procedure to test for informational sufficiency. If sufficiency is rejected, we propose a strategy to amend the VAR. Our method can be applied to FAVAR models and can be used to determine how many factors to include in such models. We apply our procedure to a VAR including TFP, unemployment and per-capita hours worked. We find that the three variables are not informationally sufficient. When adding missing information, the effects of technology shocks change dramatically

Effect of Ru loading and of Ru precursor in Ru/C catalysts for ammonia synthesis

One of the key points in the study of Ru/C catalysts for ammonia synthesis is the structure sensitivity of the reaction, which usually determines the proper metal loading, so governing the cost of the final catalyst. In the present work, the effect of Ru loading on catalytic activity and thermal stability (i.e. catalyst resistance against support methanation and metal sintering) was investigated. The optimal Ru loading was found to be around 3.5 wt.%, a value considerably lower with respect to that commonly found in literature. Furthermore, top activity was obtained with 10-15% Ru dispersion, higher dispersion values leading to less performing catalysts. Finally, the effect of some different water-soluble Ru precursors on catalyst behaviour was also investigated

Policy and Business Cycle Shocks: A Structural Factor Model Representation of the US Economy

We use a dynamic factor model to provide a semi-structural representation for 101 quarterly US macroeconomic series. We find that (i) the US economy is well described by a number of structural shocks between two and five. Focusing on the four-shock specification, we identify, using sign restrictions, two policy shocks, monetary and fiscal, and two non-policy shocks, demand and supply. We obtain the following results. (ii) Both supply and demand shocks are important sources of fluctuations; supply prevails for GDP, while demand prevails for employment and inflation. (ii) Monetary and fiscal policy shocks have sizable effects on output and prices, with no evidence of crowding-out of private aggregate demand components; both monetary and fiscal authorities implement important systematic countercyclical policies reacting to demand shocks. (iii) Negative demand shocks have a large long-run positive effect on productivity, consistently with the Schumpeterian "cleansing" view of recessions