The case of negative day-ahead electricity prices

In recent years, Germany has significantly increased its share of electricity produced from renewable sources, which is mainly due to the Renewable Energy Act (EEG). The EEG substantially impacts the dynamics of intra-day electricity prices by increasing the likelihood of negative prices. In this paper, we present a non-Gaussian process to model German intra-day electricity prices and propose an estimation procedure for this model. Most importantly, our model is able to generate extreme positive and negative spikes. A simulation study demonstrates the ability of our model to capture the characteristics of the data.

Globalizing Mediterranean identities: the overlapping spheres of Egyptian, Greek and Roman worlds at Trimithis

This article furthers recent gains made in applying globalization perspectives to the Roman world by exploring two Romano-Egyptian houses that used Roman material culture in different ways within the city known as Trimithis (modern day Amheida, in Egypt). In so doing, I suggest that concepts drawn from globalization theory will help us to disentangle and interpret how homogeneous Roman Mediterranean goods may appear heterogeneous on the local level. This theoretical vantage is broadly applicable to other regions in the Roman Mediterranean, as well as other environments in which individuals reflected a multifaceted relationship with their local identity and the broader social milieu.

Stylised worlds: Colour Separation Overlay in BBC television plays of the 1970s

This essay aims to understand and interrogate the use of Colour Separation Overlay (CSO) as a mode of experimental production and aesthetic innovation in television drama in the 1970s. It sets out to do this by describing, accounting for and evaluating CSO as a production technique, considering the role of key production personnel, and analysing four specific BBC productions. Deploying methodologies of archival research, practitioner interview, and close textual analysis, the essay also delivers a significant reassessment of the role of the producer and designer in the conceptualisation and realisation of small-screen dramatic fiction.

Transreal proof of the existence of universal possible worlds

Transreal arithmetic is total, in the sense that the fundamental operations of addition, subtraction, multiplication and division can be applied to any transreal numbers with the result being a transreal number [1]. In particular division by zero is allowed. It is proved, in [3], that transreal arithmetic is consistent and contains real arithmetic. The entire set of transreal numbers is a total semantics that models all of the semantic values, that is truth values, commonly used in logics, such as the classical, dialetheaic, fuzzy and gap values [2]. By virtue of the totality of transreal arithmetic, these logics can be implemented using total, arithmetical functions, specifically operators, whose domain and counterdomain is the entire set of transreal numbers

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology.

Health in Brazil 5 Violence and injuries in Brazil: the effect, progress made, and challenges ahead

Although there are signs of decline, homicides and traffic-related injuries and deaths in Brazil account for almost two-thirds of all deaths from external causes. In 2007, the homicide rate was 26.8 per 100 000 people and traffic-related mortality was 23.5 per 100 000. Domestic violence might not lead to as many deaths, but its share of violence-related morbidity is large. These are important public health problems that lead to enormous individual and collective costs. Young, black, and poor men are the main victims and perpetrators of community violence, whereas poor black women and children are the main victims of domestic violence. Regional differentials are also substantial. Besides the sociocultural determinants, much of the violence in Brazil has been associated with the misuse of alcohol and illicit drugs, and the wide availability of firearms. The high traffic-related morbidity and mortality in Brazil have been linked to the chosen model for the transport system that has given priority to roads and private-car use without offering adequate infrastructure. The system is often poorly equipped to deal with violations of traffic rules. In response to the major problems of violence and injuries, Brazil has greatly advanced in terms of legislation and action plans. The main challenge is to assess these advances to identify, extend, integrate, and continue the successful ones.