THE PROPOSED UNITED STATES-MEXICO-CANADA NORTH AMERICAN FREE TRADE AGREEMENT: THE MEXICAN PERSPECTIVE

International Relations/Trade,

CURRENT STATE AND FUTURE DIRECTIONS OF SAEA

Teaching/Communication/Extension/Profession,

Stimulated transitions in resonant atom Majorana mixing

Massive neutrinos demand to ask whether they are Dirac or Majorana particles. Majorana neutrinos are an irrefutable proof of physics beyond the Standard Model. Neutrinoless double electron capture is not a process but a virtual $\Delta L = 2$ mixing between a parent $^AZ$ atom and a daughter $^A(Z-2)$ excited atom with two electron holes. As a mixing between two neutral atoms and the observable signal in terms of emitted two-hole X-rays, the strategy, experimental signature and background are different from neutrinoless double beta decay. The mixing is resonantly enhanced for almost degeneracy and, under these conditions, there is no irreducible background from the standard two-neutrino channel. We reconstruct the natural time history of a nominally stable parent atom since its production either by nature or in the laboratory. After the time periods of atom oscillations and the decay of the short-lived daughter atom, at observable times the relevant "stationary" states are the mixed metastable long-lived state and the non-orthogonal short-lived excited state, as well as the ground state of the daughter atom. We find that they have a natural population inversion which is most appropriate for exploiting the bosonic nature of the observed atomic transitions radiation. Among different observables of the atom Majorana mixing, we include the enhanced rate of stimulated X-ray emission from the long-lived metastable state by a high-intensity X-ray beam: a gain factor of 100 can be envisaged at current XFEL facilities. On the other hand, the historical population of the daughter atom ground state can be probed by exciting it with a current pulsed optical laser, showing the characteristic absorption lines: the whole population can be excited in a shorter time than typical pulse duration.Comment: 17 pages, 4 figure

Productivity and R&D sources in manufacturing and service firms in Catalonia: a regional approach

This paper draws on a sample of innovative Catalan firms to identify the effects of the two main sources of innovation —internal R&D and external R&D acquisition— on productivity in the manufacturing and service industries. The sample comprises a 3,267 firms from the CIS-4 for the years 2002-2004. We compare empirical results when applying usual OLS and quantile regression techniques. Our results suggest the different patterns attributable to the two sources of innovation as we move up from lower to higher conditional quantiles. First, the effect of the marginal effect of internal R&D on productivity in both sectors decreased as we moved up to higher productivity levels. Second, the marginal effect of external R&D acquisition increased as we moved up to higher productivity levels, especially in high-tech manufacturing industries. Our empirical results suggest that the link between internal and external R&D is complex, varying between firms’ productivity levels and between industries.

The Economics of Commonly Owned Groundwater When User Demand Is Perfectly Inelastic

This paper provides a theoretical analysis of the common-pool resource dilemma in extracting nonrenewable groundwater resources when water demand is perfectly inelastic. It complements the existing theory of groundwater use, which assumes away the possibility of demand perfect inelasticity. Under perfectly inelastic water demand, the common-pool resource dilemma is by-passed if groundwater users are equally productive in water use. If they are not, a new type of inefficiency can arise due to the lack of a rationing mechanism on the basis of productivity. Our analysis suggests that groundwater management research should pay more attention to water demand elasticity and productivity heterogeneity.common-pool resources, groundwater extraction, groundwater management, groundwater use, irrigation water demand, optimal control, pumping externality, water demand elasticity, Resource /Energy Economics and Policy,