On First-Order μ-Calculus over Situation Calculus Action Theories

In this paper we study verification of situation calculus action theories against first-order mu-calculus with quantification across situations. Specifically, we consider mu-La and mu-Lp, the two variants of mu-calculus introduced in the literature for verification of data-aware processes. The former requires that quantification ranges over objects in the current active domain, while the latter additionally requires that objects assigned to variables persist across situations. Each of these two logics has a distinct corresponding notion of bisimulation. In spite of the differences we show that the two notions of bisimulation collapse for dynamic systems that are generic, which include all those systems specified through a situation calculus action theory. Then, by exploiting this result, we show that for bounded situation calculus action theories, mu-La and mu-Lp have exactly the same expressive power. Finally, we prove decidability of verification of mu-La properties over bounded action theories, using finite faithful abstractions. Differently from the mu-Lp case, these abstractions must depend on the number of quantified variables in the mu-La formula

Local density of states in metal - topological superconductor hybrid systems

We study by means of the recursive Green's function technique the local density-of-states of (finite and semi-infinite) multi-band spin-orbit coupled semiconducting nanowires in proximity to an s-wave superconductor and attached to normal-metal electrodes. When the nanowire is coupled to a normal electrode, the zero-energy peak, corresponding to the Majorana state in the topological phase, broadens with increasing transmission between the wire and the leads, eventually disappearing for ideal interfaces. Interestingly, for a finite transmission a peak is present also in the normal electrode, even though it has a smaller amplitude and broadens more rapidly with the strength of the coupling. Unpaired Majorana states can survive close to a topological phase transition even when the number of open channels (defined in the absence of superconductivity) is even. We finally study the Andreev-bound-state spectrum in superconductor-normal metal-superconductor junctions and find that in multi-band nanowires the distinction between topologically trivial and non-trivial systems based on the number of zero-energy crossings is preserved.Comment: 11 pages, 12 figures, published versio

Non separable Werner states in spontaneous parametric down-conversion

The multiphoton states generated by high-gain spontaneous parametric down-conversion (SPDC) in presence of large losses are investigated theoretically and experimentally. The explicit form for the two-photon output state has been found to exhibit a Werner structure very resilient to losses for any value of the gain parameter, g. The theoretical results are found in agreement with the experimental data. The last ones are obtained by quantum tomography of the state generated by a high-gain SPDC.Comment: 16 pages, 6 figure

A new model to predict the influence of surface temperature on contact angle

Abstract The measurement of the equilibrium contact angle (ECA) of a weakly evaporating sessile drop becomes very challenging when the temperatures are higher than ambient temperature. Since the ECA is a critical input parameter for numerical simulations of diabatic processes, it is relevant to know the variation of the ECA with the fluid and wall temperatures. Several research groups have studied the effect of temperature on ECA either experimentally, with direct measures, or numerically, using molecular dynamic simulations. However, there is some disagreement between the authors. In this paper two possible theoretical models are presented, describing how the ECA varies with the surface temperature. These two models (called Decreasing Trend Model and Unsymmetrical Trend Model, respectively) are compared with experimental measurements. Within the experimental errors, the equilibrium contact angle shows a decrease with increasing surface temperatures on the hydrophilic surface. Conversely the ECA appears approximately constant on hydrophobic surfaces for increasing wall temperatures. The two conclusions for practical applications for weakly evaporating conditions are that (i) the higher the ECA, the smaller is the effect of the surface temperature, (ii) a good evaluation of the decrease of the ECA with the surface temperature can be obtained by the proposed DTM approach

The hidden burden of food waste: The double energy waste in Italy

The energy intensity of modern food systems represents a major issue in a scenario of decreasing oil resources and increasing population. Beside the use of renewable energy, an increased efficiency in food systems could contribute to reduce fossil fuels dependence. In this sense, food losses and waste (FLW) have crucial consequences on the energy balance. Based on the concept of "embodied energy", food wastage can be framed as a double waste of energy, both in terms of non-consumed food energy and the inputs used for production. Secondary data regarding direct and indirect energy inputs and FLW have been collected for the Italian food chain to estimate the embodied energy of food waste. Since in 2011 the production and distribution of food implied the use of 822 PJ and 18 Mt of food was discarded, 67 PJ of food energy and 100 PJ of embodied energy were wasted. These figures are equivalent to 12.2% of the total nutritional energy output and to 1.3% of the final energy use in Italy, respectively. The concept of double energy waste sheds new light on the intertwined relationship between energy and food security, suggesting that appropriate food waste reduction policies could result in a higher food production level and relevant energy savings

Field trip to the Ischia resurgent caldera, a journey across an active volcano in the Gulf of Naples

Ischia is one of the most impressive examples of post-caldera resurgence in the world, with its almost 1,000 m of uplift in less than 30 ka. This three-days field trip will lead the participants through the geological and volcanological history of the island, illustrating the volcanic and related hazardous phenomena threatening about 50,000 inhabitants. Effusive and explosive eruptions, catastrophic earthquakes and huge debris-avalanches struck the island that, since Neolithic times, experienced a complex history of alternating human colonization and natural disasters. The field trip consists of three routes: 1) the circumnavigation of the island, aimed to outline its main volcanological, geomorphological and tectonic features and to observe the oldest volcanic rocks exposed, stimulating discussions about coastal evolution and the relationships between volcanism, volcano-tectonism and slope instability; 2) an onland excursion on peculiar aspects of the products related to Ischia more recent period of volcanic activity; 3) a route focusing on the Mt. Epomeo Green Tuff caldera forming eruptions (55-60 ka), encouraging a discussion on the dynamics of the intracalderic resurgence and the geomorphological evolution of the Mt. Epomeo slopes, with ongoing Mass Rock Creep (MRC) processes culminating in rockavalanche, debris-avalanche and lahar deposits

The licensing and selling of inventions by US universities

Abstract Our study analyzes the patent transactions of the top 58 US universities in the yeas from 2002 to 2010. We find that 37.0% of the patents granted at the United States Patent and Trademark Office (USPTO) have been involved in a form of monetization. Among them, 29.7% have been licensed out, 5.9% have been reassigned to other universities, National Laboratories, federal agencies or non-profit entities, and 1.3% have been transferred to companies. We investigate the patent characteristics associated with each monetization channel (i.e., licensing and outright sale). We also introduce a set of survival model analyses to control for the dynamic nature of the monetization process. The transacted inventions in the portfolio (and, in particular, the licensed ones) are peculiar over several dimensions: they show higher value or technical merit, higher legal robustness, and higher complexity. Licensed patents differ from reassigned ones especially for a higher technological complexity. Patents transferred to companies are not frequent in the university core fields, but the corresponding market for technology is able to select those with higher value and legal robustness

Surface-acoustic-wave driven planar light-emitting device

Electroluminescence emission controlled by means of surface acoustic waves (SAWs) in planar light-emitting diodes (pLEDs) is demonstrated. Interdigital transducers for SAW generation were integrated onto pLEDs fabricated following the scheme which we have recently developed. Current-voltage, light-voltage and photoluminescence characteristics are presented at cryogenic temperatures. We argue that this scheme represents a valuable building block for advanced optoelectronic architectures

Coherent transport in extremely underdoped Nd1.2Ba1.8Cu3Oz nanostructures

Proximity-effect and resistance magneto-fluctuations measurements in submicron Nd1.2Ba1.8Cu3Oz (NBCO) nano-loops are reported to investigate coherent charge transport in the non-superconducting state. We find an unexpected inhibition of cooper pair transport, and a destruction of the induced superconductivity, by lowering the temperature from 6K to 250mK. This effect is accompanied by a significant change in the conductance-voltage characteristics and in the zero bias conductance response to the magnetic field pointing to the activation of a strong pair breaking mechanism at lower temperature. The data are discussed in the framework of mesoscopic effects specific to superconducting nanostructures, proximity effect and high temperature superconductivity.Comment: to appear on new journal of Physic