897 research outputs found

    Increasing Market Interconnection: an Analysis of the Italian Electricity Spot Market

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    We estimate the benefits (in terms of savings to end-users)resulting from an improved interconnectivity in the Italian electricity spot market. The market is currently divided into two geographic zones \u2013 North and South \u2013 with limited inter-zonal transmission capacity that often induces congestion, and hence potential inefficiency. By simulating a fully interconnected market, we predict that the total spot market expenditure would reduce substantially. Moreover, since savings do not increase linearly with the size of new transmission capacity, even a slight increment to transmission capacity is found to substantially reduce endusers' expenditures. Finally, our analysis shows that the (partly State owned) dominant firm in the market is not maximizing short-term profits

    Kleene Algebra with Converse

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    International audienceThe equational theory generated by all algebras of binary relations with operations of union, composition, converse and reflexive transitive closure was studied by Bernátsky, Bloom, Ésik, and Stefanescu in 1995. We reformulate some of their proofs in syntactic and elementary terms, and we provide a new algorithm to decide the corresponding theory. This algorithm is both simpler and more efficient; it relies on an alternative automata construction, that allows us to prove that the considered equational theory lies in the complexity class PSPACE. Specific regular languages appear at various places in the proofs. Those proofs were made tractable by considering appropriate automata recognising those languages, and exploiting symmetries in those automata

    Cleaved surface of i-AlPdMn quasicrystals: Influence of the local temperature elevation at the crack tip on the fracture surface roughness

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    Roughness of i-AlPdMn cleaved surfaces are presently analysed. From the atomic scale to 2-3 nm, they are shown to exhibit scaling properties hiding the cluster (0.45 nm) aperiodic structure. These properties are quantitatively similar to those observed on various disordered materials, albeit on other ranges of length scales. These properties are interpreted as the signature of damage mechanisms occurring within a 2-3 nm wide zone at the crack tip. The size of this process zone finds its origin in the local temperature elevation at the crack tip. For the very first time, this effect is reported to be responsible for a transition from a perfectly brittle behavior to a nanoductile one.Comment: 8 page

    Vegetation outlines of two active rock glaciers with contrasting lithology

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    Rock glaciers are periglacial landforms consisting of coarse debris with interstitial ice or ice core, characterized by creeping due to ice deformation. These landforms are drawing the attention of plant ecologist as harsh habitats and potential refugia in the global change context. Our aim was to describe the vegetation outlines of two active rock glaciers of the Ortles-Cevedale Massif (Central Italian Alps) on different substrates (silicate and carbonate) and compare them with the neighboring stable slopes and scree slopes. Two hypotheses were tested: 1) rock glaciers differ from the surrounding landforms for the presence of cold-adapted plant communities; 2) rock glacier plant communities indicate similar microclimatic conditions in spite of the contrasting lithology. Data were collected by phytosociological method performing 80 relev\ue9s of 25 m\ub2. Plant communities were compared by a cluster analysis based on the presence/absence species matrix and species relative frequencies for each landform were calculated. The cluster analysis separated first for all the two sites; afterwards, the landforms were differently discerned each other depending on the site. Despite the remarkable floristic differences due to the substrate, the vegetation of both rock glaciers suggest a general adjustment to cold-moist microclimate and long-lasting snow cover, differentiating more or less evidently from the adjacent scree slopes and enhancing the survival of nival entities at the elevation of alpine grasslands

    Child protection outcomes of the Australian Nurse Family Partnership Program for Aboriginal infants and their mothers in Central Australia

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    © 2018 Segal et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background The Nurse Family Partnership Program developed in the USA, designed to improve mother and infant/child outcomes, has reported lower rates of child protection system involvement. The study tested the hypothesis that an adapted Nurse Family Partnership Program implemented in an Aboriginal community in Central Australia (the FPP) would improve Child Protection outcomes. Methods This was a retrospective and prospective cohort study drawing on linked administrative data, including birth registry, primary health care client information system, FPP program data, and child protection data. Participants were children of women eligible for the FPP program (an exposed and a control group of women, eligible but not referred) live-born between 1/3/2009 (program commencement) and 31/12/2015. Child protection data covered all reports, investigations, substantiations and out-of-home care placements from the time of the child’s birth to 31/12/2016. Generalised linear modelling was used to estimate the relative risk (RR) of involvement with child protection and type of involvement (report, investigation, substantiation, out-of-home-care placement) among FPP and control children. Results FPP mothers (n = 291) were on average younger, were more likely to be first-time mothers and experiencing housing instability than control mothers (n = 563). Among younger mothers 20 years, FPP children had statistically significantly lower rates of involvement with child protection (ARRreport = 0.49, 95% CI: 0.29 to 0.82; ARRinvestigation = 0.34, 95% CI: 0.19 to 0.64; ARRsubstantiation = 0.45, 95% CI: 0.21 to 0.96) and experience fewer days in care (ARR = 0.10, 95% CI: 0.02 to 0.48). Among children of first-time mothers, FPP children also had statistically significantly lower rates of involvement with child protection (ARRreport = 0.50, 95% CI: 0.30 to 0.83; ARRinvestigation = 0.36, 95% CI: 0.19 to 0.67; ARRsubstantiation = 0.38, 95% CI: 0.18 to 0.80) and fewer days in care (ARR = 0.06, 95% CI: 0.01 to 0.27). Conclusion Study results suggest a modified Nurse Family Partnership delivered by an Indigenous community-controlled organisation may have reduced child protection system involvement in a highly vulnerable First Nations population, especially in younger or first-time mothers. Testing these results with an RCT design is desirable

    High pressure and high temperature Brillouin scattering measurements of pyrope single crystals using flexible CO 2 laser heating systems

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    Single-crystal Brillouin scattering measurements are important for interpreting seismic velocities within the Earth and other planetary interiors. These measurements are rare, however, at temperatures above 1000 K, due to the fact that the transparent samples cannot be heated by common laser heating systems operating at a wavelength on the order of 1 ÎĽm. Here we present Brillouin scattering data on pyrope collected at pressures up to 23.8 GPa and temperatures between 850 and 1900 K using a novel CO2 laser heating system confined in either a flexible hollow silica waveguide or an articulated arm with mirrors mounted in each junction to direct the laser to the exit point. Pyrope has been chosen because it has been extensively studied at high pressures and moderate temperatures and therefore it is an excellent sample for bench-marking the CO2 laser heating system. The new high-temperature velocity data collected in this study allow the room pressure thermal parameters of pyrope to be constrained more tightly, resulting in values that reproduce the temperature dependence of the unit-cell volume of pyrope measured in recent studies at ambient pressure. Aggregate wave velocities of pyrope calculated along an adiabat using the thermoelastic parameters determined in this study are larger than those obtained using published values, implying that velocities for many mantle components may be underestimated at mantle temperatures because high temperature experimental data are lacking

    Completeness and Incompleteness of Synchronous Kleene Algebra

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    Synchronous Kleene algebra (SKA), an extension of Kleene algebra (KA), was proposed by Prisacariu as a tool for reasoning about programs that may execute synchronously, i.e., in lock-step. We provide a countermodel witnessing that the axioms of SKA are incomplete w.r.t. its language semantics, by exploiting a lack of interaction between the synchronous product operator and the Kleene star. We then propose an alternative set of axioms for SKA, based on Salomaa's axiomatisation of regular languages, and show that these provide a sound and complete characterisation w.r.t. the original language semantics.Comment: Accepted at MPC 201
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