Search results for "response"
showing 10 items of 4136 documents
Impact of Converter-Interfaced Generation to the Frequency Response of the European Power System
2019
The increase of converter-interfaced generation (CIG) typically related to renewable energy sources is progressively causing a significant change of power systems operation. The curtailment of synchronous generation with the consequent reduction of the overall kinetic energy is one of the related issues, currently under investigation in academia and industry. The work considers the problem of overall inertia reduction from a large-scale point of view, analyzing the impact of different CIG integration levels to the frequency response of the power system of Continental Europe. The kinetic energy is evaluated for each country of the synchronous area, and the system is modified substituting con…
Inter-area oscillations in the 500-kV Vietnamese power system
2019
The paper presents the study of the 500-kV Vietnamese power system. The oscillatory response of the system is analyzed both with a modal analysis and a time domain analysis. The 500-kV system of Vietnam is modeled in details, including all the power plants with the corresponding regulators. The model is developed in collaboration with the Institute of Energy Science IES-VAST of Vietnam and it is validated with the data provided by the National Load Dispatch Centre (NLDC) of Vietnam. The simulation results reveal a clear identification of potential inter-area oscillations between North and South of the Country. A worsening of the observed phenomenon should be considered as possible, especial…
AQUATIC ACOUSTIC NOISE: BEHAVIORAL AND MOLECULAR RESPONSES IN ECHINODERMS, THE CASE OF A. LIXULA (LINNAEUS, 1758) SEA URCHINS
2018
Anthropic noise is considered a real pollutant, in particular the submarine noise. The impact on biodiversity is not yet sufficiently understood. Further research is needed to evaluate any negative effects. The noises associated with anthropogenic activities are increasing: shipments, seismic surveys, sonar, recreational rowing and future mineral extraction activities from ocean depths (DSM). These noises are having an impact on the welfare of many marine species. The understanding of the effects on biodiversity could be important for the creation of guidelines, laws or rules for the most environmentally sustainable exploitation of natural resources. Our study aims to investigate the motili…
Effects of waterg gun on echinoderms: biochemical changes on sea urchin (Arbacia lixula) and sea cucumber (Holothuria tubulosa)
2019
Sources Airguns and Waterguns are used in seismic exploration the marine seafloor for different purposes such as oil and gas search, or geological-geodynamic reconstruction. In this technique a bubble of compressed air is produced with a consequently production of loud sound wave penetrating the ocean floor. The impact of seismic Airguns was assessed in some cetaceans (Kyhn et al. 2019), fish species and invertebrate (Carroll et al. 2017), but we need to know more. In this study we evaluate the biochemical changes in sea urchin (Arbacia lixula) and sea cucumber (Holothuria tubulosa) exposed to a 20 minutes of watergun noise (1 pulse each 10 s) at a distance of 50 m. For each species 40 indi…
Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora
2011
Abstract Background The best documented survival responses of organisms to past climate change on short (glacial-interglacial) timescales are distributional shifts. Despite ample evidence on such timescales for local adaptations of populations at specific sites, the long-term impacts of such changes on evolutionary significant units in response to past climatic change have been little documented. Here we use phylogenies to reconstruct changes in distribution and flowering ecology of the Cape flora - South Africa's biodiversity hotspot - through a period of past (Neogene and Quaternary) changes in the seasonality of rainfall over a timescale of several million years. Results Forty-three dist…
Earnings management to exceed thresholds in continental and Anglo-Saxon accounting models: The British and French cases
2017
International audience; The purpose of this paper is to compare the extent to which French and British firms manage their earnings in order to avoid losses, decreases in earnings and earnings below the forecasts of analysts. Further, this study aims to investigate the factors that potentially influence earnings management to exceed thresholds with reference to the Anglo-Saxon and continental accounting models. Britain and France, correspondingly, belong to those different socio-economic environments. Based on a panel data of 1771 French and 2057 British firm-year observations during the period 2002–2012, we show that all firms considered manage earnings to beat zero and last year’s earnings…
Origin of the large spectral shift in electroluminescence in a blue light emitting cationic iridium(III) complex
2007
A new, but archetypal compound [ Ir( ppy- F-2) (2)Me(4)phen] PF6, where ppy- F2 is 2-(2',4'- fluorophenyl) pyridine and Me(4)phen is 3,4,7,8- tetramethyl- 1,10- phenanthroline, was synthesized and used to prepare a solid-state light-emitting electrochemical cell (LEEC). This complex emits blue light with a maximum at 476 nm when photoexcited in a thin film, with a photoluminescence quantum yield of 52%. It yields an efficient single-component solid-state electroluminescence device with a current efficiency reaching 5.5 cd A(-1) and a maximum power efficiency of 5.8 Lm Watt(-1). However, the electroluminescence spectrum is shifted with respect to the photoluminescence spectrum by 80 nm resul…
Method effects associated with negative worded items in the 29 items spanish version of Ryff's Well-being Scales
2018
Aim Although they have been frequently used in the literature, there has been much confusion concerning Ryff’s Well-being Scales, such as their factor structure and the effects of method due to the use of reversed items. A common practice nowadays is the use of positively worded items and reversed forms, in order to reduce response bias. However, in many different studies have been seen that this practice introduce method effects in the scores, leading to problems of reliability and validity. This work had two goals: first, to verify the factor structure of the 29-item Spanish version of the original Ryff’s Well-being Scale in an athlete population, and second, to determine whether the meth…
Life in varying environments: experimental evidence for delayed effects of juvenile environment on adult life history
2011
Summary 1. The effects of environment experienced during early development on phenotype as an adult has started to gain vast amounts of interest in various taxa. Some evidence on long-term effects of juvenile environment is available, but replicated experimental studies in wild animals are still lacking. 2. Here we report the first replicated experiment in wild mammals which examines the long-term effects of juvenile and adult environments on individual fitness (reproduction, survival and health). The early development of bank vole (Myodes glareolus) individuals took place in either foodsupplemented or un-supplemented outdoor enclosures. After the summer, adult individuals were reciprocally…
Numerical response of predators to large variations of grassland vole abundance, long-term community change and prey switches
2020
AbstractVoles can reach high densities with multi-annual population fluctuations of large amplitude, and they are at the base of large and rich communities of predators in temperate and arctic food webs. This status places them at the heart of management conflicts wherein crop protection and health concerns are often raised against conservation issues. Here, a 20-year survey describes the effects of large variations in grassland vole populations on the densities and the daily theoretical food intakes (TFI) of vole predators based on roadside counts. Our results show how the predator community responds to prey variations of large amplitude and how it reorganized with the increase in a domina…