Renewable energy support policy based on contracts for difference and bilateral negotiation

ABSTRACT: The European Union has been one of the major drivers of the development of renewable energy. The energy policies of most European countries have involved subsidized tariffs, such as the feed-in tariff in Portugal, the regulated tariff and the market price plus premium in Spain, and the Renewables Obligation in UK, that came into effect in 2002. Recently, UK has made some reforms and started to consider contracts for difference (CfDs) as a key element of the energy policy. This paper presents a support policy based on CfDs and bilateral negotiation. The first phase consists in a CfD auction and the second phase involves a bilateral negotiation between a Government and each of the selected investors. The paper also presents a case-study to analyze the potential benefits of the support policy. It was performed with the help of the MATREM system. The preliminary results indicate some advantages for the Government (and, in some cases, for the investors as well).info:eu-repo/semantics/publishedVersio

A Monte Carlo Approach to Measure the Robustness of Boolean Networks

Emergence of robustness in biological networks is a paramount feature of evolving organisms, but a study of this property in vivo, for any level of representation such as Genetic, Metabolic, or Neuronal Networks, is a very hard challenge. In the case of Genetic Networks, mathematical models have been used in this context to provide insights on their robustness, but even in relatively simple formulations, such as Boolean Networks (BN), it might not be feasible to compute some measures for large system sizes. We describe in this work a Monte Carlo approach to calculate the size of the largest basin of attraction of a BN, which is intrinsically associated with its robustness, that can be used regardless the network size. We show the stability of our method through finite-size analysis and validate it with a full search on small networks.Comment: on 1st International Workshop on Robustness and Stability of Biological Systems and Computational Solutions (WRSBS

Participation of wind power producers in intra-day markets : a case-study

ABSTRACT: The evolution of renewable energy has increased substantially over the past decade. Wind power producers (WPPs) can submit bids to energy markets, making short-term commitments to produce specific quantities of energy. This article presents a case-study to analyze the benefits of the active participation of wind power producers in energy markets, particularly intra-day markets. The case-study is carried out with the help of the MATREM system. The preliminary results indicate a reduction of the deviations of WPPs, but also a decreasing in their remuneration. Thus, the results highlight to some extent the importance of new market mechanisms to enable the active participation of WPPs in markets, without support policies.info:eu-repo/semantics/publishedVersio

Sanitizing the fortress: protection of ant brood and nest material by worker antibiotics

Social groups are at particular risk for parasite infection, which is heightened in eusocial insects by the low genetic diversity of individuals within a colony. To combat this, adult ants have evolved a suite of defenses to protect each other, including the production of antimicrobial secretions. However, it is the brood in a colony that are most vulnerable to parasites because their individual defenses are limited, and the nest material in which ants live is also likely to be prone to colonization by potential parasites. Here, we investigate in two ant species whether adult workers use their antimicrobial secretions not only to protect each other but also to sanitize the vulnerable brood and nest material. We find that, in both leaf-cutting ants and weaver ants, the survival of the brood was reduced and the sporulation of parasitic fungi from them increased, when the workers nursing them lacked functional antimicrobial-producing glands. This was the case for both larvae that were experimentally treated with a fungal parasite (Metarhizium) and control larvae which developed infections of an opportunistic fungal parasite (Aspergillus). Similarly, fungi were more likely to grow on the nest material of both ant species if the glands of attending workers were blocked. The results show that the defense of brood and sanitization of nest material are important functions of the antimicrobial secretions of adult ants and that ubiquitous, opportunistic fungi may be a more important driver of the evolution of these defenses than rarer, specialist parasites

Plant population and spatial arrangement studies in the intercropping of maize and beans in Northeast Brazil.

In Northeast Brazil the peasant farmer use to raise their cropa in mixture, and the intercropping of maise and beans is very frequent.Paper for International Intercropping Workshop at ICRISAT, Hydederabad, India, from jannuary 10 at 13, 1979

New type II Cepheids from VVV data towards the Galactic center

The Galactic center (GC) is the densest region of the Milky Way. Variability surveys towards the GC potentially provide the largest number of variable stars per square degree within the Galaxy. However, high stellar density is also a drawback due to blending. Moreover, the GC is affected by extreme reddening, therefore near infrared observations are needed. We plan to detect new variable stars towards the GC, focusing on type II Cepheids (T2Cs) which have the advantage of being brighter than RR Lyrae stars. We perform parallel Lomb-Scargle and Generalized Lomb-Scargle periodogram analysis of the $K_s$-band time series of the VISTA variables in the Via Lactea survey, to detect periodicities. We employ statistical parameters to clean our sample. We take account of periods, light amplitudes, distances, and proper motions to provide a classification of the candidate variables. We detected 1,019 periodic variable stars, of which 164 are T2Cs, 210 are Miras and 3 are classical Cepheids. We also found the first anomalous Cepheid in this region. We compare their photometric properties with overlapping catalogs and discuss their properties on the color-magnitude and Bailey diagrams. We present the most extensive catalog of T2Cs in the GC region to date. Offsets in E($J-K_s$) and in the reddening law cause very large ($\sim$1-2 kpc) uncertainties on distances in this region. We provide a catalog which will be the starting point for future spectroscopic surveys in the innermost regions of the Galaxy.Comment: A&A, accepte

Walk on the wild side: Temporarily unstable paths and multiplicative sunspots

We propose a generalization of the rational expectations framework to allow for temporarily unstable paths. Our approach introduces multiplicative sunspot shocks and it yields drifting parameters and stochastic volatility. Then, we provide an econometric strategy to estimate this generalized model on the data. The methodology allows the data to choose between different possible alternatives: determinacy, indeterminacy, and temporary instability. We apply our methodology to US in?ation dynamics in the 1970s through the lens of a simple New Keynesian model. When temporarily unstable paths are allowed, the data unambiguously select them to explain the stag?ation period in the 1970s

Retinal gene therapy with a large MYO7A cDNA using adeno-associated virus.

Usher 1 patients are born profoundly deaf and then develop retinal degeneration. Thus they are readily identified before the onset of retinal degeneration, making gene therapy a viable strategy to prevent their blindness. Here, we have investigated the use of adeno-associated viruses (AAVs) for the delivery of the Usher 1B gene, MYO7A, to retinal cells in cell culture and in Myo7a-null mice. MYO7A cDNA, under control of a smCBA promoter, was packaged in single AAV2 and AAV5 vectors and as two overlapping halves in dual AAV2 vectors. The 7.9-kb smCBA-MYO7A exceeds the capacity of an AAV vector; packaging of such oversized constructs into single AAV vectors may involve fragmentation of the gene. Nevertheless, the AAV2 and AAV5 single vector preparations successfully transduced photoreceptor and retinal pigment epithelium cells, resulting in functional, full-length MYO7A protein and correction of mutant phenotypes, suggesting successful homologous recombination of gene fragments. With discrete, conventional-sized dual AAV2 vectors, full-length MYO7A was detected, but the level of protein expression was variable, and only a minority of cells showed phenotype correction. Our results show that MYO7A therapy with AAV2 or AAV5 single vectors is efficacious; however, the dual AAV2 approach proved to be less effective

Tests of Bayesian Model Selection Techniques for Gravitational Wave Astronomy

The analysis of gravitational wave data involves many model selection problems. The most important example is the detection problem of selecting between the data being consistent with instrument noise alone, or instrument noise and a gravitational wave signal. The analysis of data from ground based gravitational wave detectors is mostly conducted using classical statistics, and methods such as the Neyman-Pearson criteria are used for model selection. Future space based detectors, such as the \emph{Laser Interferometer Space Antenna} (LISA), are expected to produced rich data streams containing the signals from many millions of sources. Determining the number of sources that are resolvable, and the most appropriate description of each source poses a challenging model selection problem that may best be addressed in a Bayesian framework. An important class of LISA sources are the millions of low-mass binary systems within our own galaxy, tens of thousands of which will be detectable. Not only are the number of sources unknown, but so are the number of parameters required to model the waveforms. For example, a significant subset of the resolvable galactic binaries will exhibit orbital frequency evolution, while a smaller number will have measurable eccentricity. In the Bayesian approach to model selection one needs to compute the Bayes factor between competing models. Here we explore various methods for computing Bayes factors in the context of determining which galactic binaries have measurable frequency evolution. The methods explored include a Reverse Jump Markov Chain Monte Carlo (RJMCMC) algorithm, Savage-Dickie density ratios, the Schwarz-Bayes Information Criterion (BIC), and the Laplace approximation to the model evidence. We find good agreement between all of the approaches.Comment: 11 pages, 6 figure

Disorder Induced Localized States in Graphene

We consider the electronic structure near vacancies in the half-filled honeycomb lattice. It is shown that vacancies induce the formation of localized states. When particle-hole symmetry is broken, localized states become resonances close to the Fermi level. We also study the problem of a finite density of vacancies, obtaining the electronic density of states, and discussing the issue of electronic localization in these systems. Our results also have relevance for the problem of disorder in d-wave superconductors.Comment: Replaced with published version. 4 pages, 4 figures. Fig. 1 was revise