1,843 research outputs found

    Do British wind generators behave strategically in response to the Western Link interconnector?

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    In Britain, the key source of renewable generation is wind, most abundant on the west coast of Scotland, where there is relatively little demand. For this reason, an interconnector, the Western Link, was built to take electricity closer to demand. When the Link is operating, payments by National Grid to constrain wind farms not to produce will be lower, we may predict, since fewer or less restrictive constraints need be imposed. But the Link has not been working consistently. We empirically estimate the link’s value. Focusing on the three most recent episodes of outage, starting on 4th May 2018 up to 25th September 2019, our essential approach is to treat these outages as a natural experiment using hourly data. Our results reveal that the Link had an important role in costs saved and price constrained and MWh curtailed reductions. We estimate a cost-saving of almost £30m. However, the saving appears to drop over time, so we investigate wind farms’ behavior. We find that wind farms behave strategically since the accuracy of wind forecasting depends on the relevant prices impacting their earnings

    Italy’s latest legislation on accounting fraud highlights the country’s difficulty in pursuing real economic and political reform

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    Italy has a longstanding corruption problem which the Italian Prime Minister, Matteo Renzi, has pledged to address. Andrea Lorenzo Capussela and Vito Intini write on a recent piece of legislation introduced in June which alters the rules on accounting fraud. They argue that the legislation has opened up a significant loophole and is indicative of the Italian political system’s inability to produce meaningful political and economic reforms

    There is little evidence that the proposed reform of Italy’s labour market will actually generate growth or employment

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    The Italian government has outlined a number of policies aimed at reforming Italy’s labour market, with the proposals receiving final approval in the Italian Senate on 3 December. Andrea Lorenzo Capussela and Vito Intini assess whether the reforms, which have proved controversial, will actually have the desired effect in generating economic growth and employment. They write that while increasing the flexibility of the Italian labour market may be desirable, the rigidity of the labour market is not the biggest obstacle to growth in the country. They argue instead that the quality of Italy’s political institutions and governance standards should be the key focus of reform efforts

    External pressure is needed to help Italy tackle its persistent corruption problem

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    Corruption has been a persistent problem in Italy, with the country receiving one of the lowest scores of EU member states in Transparency International’s latest ‘Corruption Perceptions Index’. Andrea Lorenzo Capussela and Vito Intini provide a comprehensive look at the problem, noting that on several measures corruption has increased since the late 1990s. They argue that corruption in Italy represents a ‘resilient equilibrium’, whereby the political system provides little incentive for parties to tackle the problem. They suggest that external pressure from other countries in the EU may offer one route to breaking this cycle

    A new data analysis framework for the search of continuous gravitational wave signals

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    Continuous gravitational wave signals, like those expected by asymmetric spinning neutron stars, are among the most promising targets for LIGO and Virgo detectors. The development of fast and robust data analysis methods is crucial to increase the chances of a detection. We have developed a new and flexible general data analysis framework for the search of this kind of signals, which allows to reduce the computational cost of the analysis by about two orders of magnitude with respect to current procedures. This can correspond, at fixed computing cost, to a sensitivity gain of up to 10%-20%, depending on the search parameter space. Some possible applications are discussed, with a particular focus on a directed search for sources in the Galactic center. Validation through the injection of artificial signals in the data of Advanced LIGO first observational science run is also shown.Comment: 21 pages, 8 figure

    An improved algorithm for narrow-band searches of continuous gravitational waves

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    Continuous gravitational waves signals, emitted by asymmetric spinning neutron stars, are among the main targets of current detectors like Advanced LIGO and Virgo. In the case of sources, like pulsars, which rotational parameters are measured through electromagnetic observations, typical searches assume that the gravitational wave frequency is at a given known fixed ratio with respect to the star rotational frequency. For instance, for a neutron star rotating around one of its principal axis of inertia the gravitational signal frequency would be exactly two times the rotational frequency of the star. It is possible, however, that this assumption is wrong. This is why search algorithms able to take into account a possible small mismatch between the gravitational waves frequency and the frequency inferred from electromagnetic observations have been developed. In this paper we present an improved pipeline to perform such narrow-band searches for continuous gravitational waves from neutron stars, about three orders of magnitude faster than previous implementations. The algorithm that we have developed is based on the {\it 5-vectors} framework and is able to perform a fully coherent search over a frequency band of width O\mathcal{O}(Hertz) and for hundreds of spin-down values running a few hours on a standard workstation. This new algorithm opens the possibility of long coherence time searches for objects which rotational parameters are highly uncertain.Comment: 19 pages, 8 figures, 6 tables, submitted to CQ

    A semi-coherent analysis method to search for continuous gravitational waves emitted by ultra-light boson clouds around spinning black holes

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    As a consequence of superradiant instability induced in Kerr black holes, ultra-light boson clouds can be a source of persistent gravitational waves, potentially detectable by current and future gravitational-wave detectors. These signals have been predicted to be nearly monochromatic, with a small steady frequency increase (spin-up), but given the several assumptions and simplifications done at theoretical level, it is wise to consider, from the data analysis point of view, a broader class of gravitational signals in which the phase (or the frequency) slightly wander in time. Also other types of sources, e.g. neutron stars in which a torque balance equilibrium exists between matter accretion and emission of persistent gravitational waves, would fit in this category. In this paper we present a robust and computationally cheap analysis pipeline devoted to the search of such kind of signals. We provide a full characterization of the method, through both a theoretical sensitivity estimation and through the analysis of syntethic data in which simulated signals have been injected. The search setup for both all-sky searches and higher sensitivity directed searches is discussed.Comment: 13 pages, 13 figure

    A method to search for long duration gravitational wave transients from isolated neutron stars using the generalized FrequencyHough

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    We describe a method to detect gravitational waves lasting O(hoursdays)O(hours-days) emitted by young, isolated neutron stars, such as those that could form after a supernova or a binary neutron star merger, using advanced LIGO/Virgo data. The method is based on a generalization of the FrequencyHough (FH), a pipeline that performs hierarchical searches for continuous gravitational waves by mapping points in the time/frequency plane of the detector to lines in the frequency/spindown plane of the source. We show that signals whose spindowns are related to their frequencies by a power law can be transformed to coordinates where the behavior of these signals is always linear, and can therefore be searched for by the FH. We estimate the sensitivity of our search across different braking indices, and describe the portion of the parameter space we could explore in a search using varying fast Fourier Transform (FFT) lengths.Comment: 15 figure

    A polymer supported palladium(II) \u3b2-ketoesterate complex as active and recyclable pre-catalyst for selective reduction of quinolines in water with sodium borohydride

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    A polymer supported palladium catalyst, obtained by copolymerization of Pd(AAEMA)2 [AAEMA- = deprotonated form of 2-(acetoacetoxy) ethyl methacrylate] with ethyl methacrylate (co-monomer) and ethylene glycol dimethacrylate (cross-linker), exhibited excellent activity and selectivity for the hydrogenation of quinolines to 1,2,3,4-tetrahydroquinolines in the presence of NaBH4 as hydrogen donor in water. Both the activity and selectivity could be maintained for at least seven reaction runs. No metal leaching into solution occurred during recycles. TEM analyzes carried out on the catalyst showed that the active species were supported palladium nanoparticles having a mean size of 3 nm, which did not aggregate with the recycles

    Diazido mixed-amine platinum(IV) anticancer complexes activatable by visible-light form novel DNA adducts

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    Platinum diam(m)ine complexes, such as cisplatin, are successful anticancer drugs, but suffer from problems of resistance and side-effects. Photoactivatable PtIV prodrugs offer the potential of targeted drug release and new mechanisms of action. We report the synthesis, X-ray crystallographic and spectroscopic properties of photoactivatable diazido complexes trans,trans,trans-[Pt(N3)2(OH)2(MA)(Py)] (1; MA=methylamine, Py=pyridine) and trans,trans,trans-[Pt(N3)2(OH)2(MA)(Tz)] (2; Tz=thiazole), and interpret their photophysical properties by TD-DFT modelling. The orientation of the azido groups is highly dependent on H bonding and crystal packing, as shown by polymorphs 1 p and 1 q. Complexes 1 and 2 are stable in the dark towards hydrolysis and glutathione reduction, but undergo rapid photoreduction with UVA or blue light with minimal amine photodissociation. They are over an order of magnitude more potent towards HaCaT keratinocytes, A2780 ovarian, and OE19 oesophageal carcinoma cells than cisplatin and show particular potency towards cisplatin-resistant human ovarian cancer cells (A2780cis). Analysis of binding to calf-thymus (CT), plasmids, oligonucleotide DNA and individual nucleotides reveals that photoactivated 1 and 2 form both mono- and bifunctional DNA lesions, with preference for G and C, similar to transplatin, but with significantly larger unwinding angles and a higher percentage of interstrand cross-links, with evidence for DNA strand cross-linking further supported by a comet assay. DNA lesions of 1 and 2 on a 50 bp duplex were not recognised by HMGB1 protein, in contrast to cisplatin-type lesions. The photo-induced platination reactions of DNA by 1 and 2 show similarities with the products of the dark reactions of the PtII compounds trans-[PtCl2(MA)(Py)] (5) and trans-[PtCl2(MA)(Tz)] (6). Following photoactivation, complex 2 reacted most rapidly with CT DNA, followed by 1, whereas the dark reactions of 5 and 6 with DNA were comparatively slow. Complexes 1 and 2 can therefore give rapid potent photocytotoxicity and novel DNA lesions in cancer cells, with no activity in the absence of irradiation
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