Starburst radio galaxies: general properties, evolutionary histories and triggering

In this paper we discuss the results of a programme of spectral synthesis modelling of a sample of starburst radio galaxies in the context of scenarios for the triggering of the activity and the evolution of the host galaxies. The starburst radio galaxies -- comprising ~15 - 25% of all powerful extragalactic radio sources -- frequently show disturbed morphologies at optical wavelengths, and unusual radio structures, although their stellar masses are typical of radio galaxies as a class. In terms of the characteristic ages of their young stellar populations (YSP), the objects can be divided into two groups: those with YSP ages t_ysp < 0.1 Gyr, in which the radio source has been triggered quasi-simultaneously with the main starburst episode, and those with older YSP in which the radio source has been triggered or re-triggered a significant period after the starburst episode. Combining the information on the YSP with that on the optical morphologies of the host galaxies, we deduce that the majority of the starburst radio galaxies have been triggered in galaxy mergers in which at least one of the galaxies is gas rich. However, the triggering (or re-triggering) of the radio jets can occur immediately before, around, or a significant period after the final coalescence of the merging nuclei, reflecting the complex gas infall histories of the merger events. Overall, our results provide further evidence that powerful radio jet activity can be triggered via a variety of mechanisms, including different evolutionary stages of major galaxy mergers; clearly radio-loud AGN activity is not solely associated with a particular stage of a unique type of gas accretion event.Comment: 16 pages, 3 Figures, accepted for publication in MNRA

Experimental analysis of drainage and water storage of litter layers

International audienceMany hydrological studies of forested ecosystems focus on the study of the forest canopy and have partitioned gross precipitation into throughfall and stemflow. However, the presence of forest litter can alter the quantities of water available for soil infiltration and runoff. Little information exists regarding the value of storage and drainage parameters for litter layers. Vegetation parameters of this kind are required in physically-based and lumped conceptual models to quatify the availabilty and distribution of water. Using a rainfall simulator and laboratory conditions two main objectives were investigated using layers of recently seneced poplar leaves, fresh grass or woodchips: 1) Effect of rain intensity on storage. With this respect we found that: maximum storage (Cmax), defined as the detention of water immediately before rainfall cessation, increased with rainfall intensity. The magnitude of the increment was up to 0.5 mm kg?1 m?2 between the lowest (9.8 mm h?1) and highest (70.9 mm h?1) rainfall intensities for poplar leaves. Minimum storage (Cmin), defined as the detention of water after drainage ceased, was not influenced by rainfall intensity. Repeated wetting-draining cycles or layer thickness have no effect on Cmax or Cmin. 2) The evaluation of drainage coefficient for the Rutter model. This model was found accurate to predict storage and drainage in the case of poplar leaves, was less accurate for fresh grass and resulted in overestimations for woodchips. Additionally, the effect of an underlaying soil matrix on lateral movement of water and storage of poplar leaves was studied. Results indicated that the soil matrix have no effect on Cmax or Cmin of the litter layer. Lateral movement of water in the poplar layer was observed at intermediate rainfall intensities (30.2 and 40.4 mm h?1), but not a the lowest or highest rates

Potential of energy flexible buildings: Evaluation of DSM strategies using building thermal mass

Energy flexible buildings through smart demand-side management (DSM) or smart demand response (DR) using efficient energy storage, are currently one of the most promising options to deploy low-carbon technologies in the electricity networks without the need of reinforcing existing networks. Although, many ignore the potential, economic and energetic benefits these alternatives could hold for buildings, users and tariffs. In the study carried out a control system of demand management measures is analyzed, based on the use of the buildings' thermal mass as thermal storage (preheating, precooling and night ventilation). This demand management system is analyzed in five existing residential buildings in the so-called reference scenario (construction, user and current prices). Subsequently, comes the analysis of the optimal manage- ment strategy choice from the system, when facing changes in the housings' constructive characteristics and electric tariffs. The dynamism of the management system stands out from the results achieved, as well as the de- pendence of the possible strategy choices on the climate zones. In the reference situation, the maximum economic savings obtained after the implementation of the management system correspond to 3.2% for heating and 8.5% for cooling. In this same manner, when the buildings are previously rehabilitated, the savings can double even generating energy savings. Finally, it can be concluded that the low installation costs of these measures make them a winning solution, as long as the electric pricing and user behavior allow the required flexibility.The authors would like to take this opportunity to thank the DACAR project “Zero-Energy Balance Districts Through Algorithms of Adaptive Comfort and Optimal Management of Energy Networks” (BIA2016-77431-C2-2-R) funded by Ministry of Economy and Competitiveness (Government of Spain) and European Regional Development's Funds (ERDF) for its partial support. And the University of Seville under its Research Plan VI (VPPI-US)

Assessment of targeted selective treatment criteria to control subclinical gastrointestinal nematode infections on sheep farms

Control of sheep gastrointestinal nematode (GIN) infections mostly relies on the use of anthelmintics. Refugia-based control strategies as targeted selective treatments (TST) can delay anthelmintic resistance development, but the optimal decision criteria for selecting individuals to be treated in subclinical infection scenarios remain unclear. The present study aimed to evaluate the suitability of body condition score (BCS) and faecal egg counts (FEC) as treatment indicators and to determine their optimized threshold values for treatment in TST by determining the relationships of BCS, FEC and anthelmintic treatment with several productive parameters in pre-mating and pre-partum periods at an individual level. Deworming in pre-mating period increased BCS gain, but its magnitude was directly associated with strongyle FEC before treatment. Deworming also increased fertility in ewes with BCS 400 epg before treatment. These results showed that FEC and especially BCS can be potential decision criteria for the implementation of TST in these types of scenarios. The TST scheme derived from the present results on the control of GIN infections should include anthelmintic treatment of ewes with BCS lower than ˜ 3 approximately five weeks before mating and lambing. In the pre-lambing period, treatment may be unnecessary if flock mean strongyle FEC is lower than ˜ 200 epg, as the proportion of ewes with individual FEC > 400 epg would be very low. The results suggest that implementation of this TST scheme would provide benefits, such as the improvement of productivity, a rational management of parasites in refugia, and preservation of future efficacy of anthelmintics, in comparison to traditional deworming schemes

Efeitos da propriedade estrangeira e das Normas Internacionais de Relato Financeiro no vencimento da dívida em empresas chilenas

The objective of this article is to determine the effects of foreign ownership and International Financial Reporting Standards (IFRS) on debt maturity in Chilean companies. The study uses a fractional response model (FRM) on 20,586 companies. The results show foreign ownership has a negative and non-linear effect. Foreign ownership in Chilean firms is a substitute control means in relation to long-term debt. IFRS reduces maturity in large companies and extends them in small and medium enterprises (SMEs). These results suggest it is more important for large firms to control agency conflicts, while it is more important for SMEs to reduce information asymmetry.El objetivo de este artículo es determinar los efectos de la propiedad extranjera y de las Normas Internacionales de Información Financiera (NIIF) sobre la madurez de la deuda en las empresas chilenas. En el estudio se utiliza un modelo de respuesta fraccional (MRF) sobre 20.586 empresas. Los resultados demuestran que la propiedad extranjera tiene un efecto negativo y no lineal, transformándose en un medio de control sustituto en relación con la deuda de largo plazo. Las NIIF reducen la madurez en empresas grandes y la extiende en las pequeñas y medianas empresas (Pymes). Estos resultados sugieren que para las firmas grandes es más importante controlar conflictos de agencia, mientras que para las Pymes es más importante reducir las asimetrías de información.O objetivo deste artigo é determinar os efeitos da propriedade estrangeira e das Normas Internacionais de Relato Financeiro (IFRS) no ven- cimento da dívida em empresas chilenas. O estudo utiliza um Modelo de Resposta Fracionária (MRF) em 20.586 empresas. Os resultados mostram que a propriedade estrangeira tem efeito negativo e não linear, tornando-se um meio de controle substituto em relação à dívida de longo prazo. O IFRS reduz a maturidade em grandes empresas e as estende em Pequenas e Médias Empresas (PMEs). Esses resultados sugerem que, para grandes empresas, é mais importante controlar conflitos entre agências, enquanto para as PMEs é mais importante reduzir as assimetrias de informações

Building thermal storage technology: Compensating renewable energy fluctuations

Emerging technologies and new intelligent management systems will be needed to rise to the energy challenges posed by buildings today. Thermally activated building systems (TABS) are attracting growing interest on the back of their energy savings potential. The TABS studied in this article, a new prefabricated panel designed for installation in residential building façades, was characterised by the high thermal inertia afforded by the phase change materials in its composition. The design and assessment of the potential savings derived from TABS require specific characterisation methodologies to estimate the amount of useful energy available to control the indoor environment. A two-stage approach was adopted for the TABS studied here with ``ideal'' operating control (the building is assumed to be at a constant desired temperature). The first stage involved a simplified method for characterising system behaviour based on performance maps developed from CFD simulations. Such maps can be used to quickly assess changes in system energy performance following on variations in design and operating parameters. In the second, the TABS was integrated into a building with a simplified model to assess monthly energy demand to evaluate the system potential for energy savings in representative types of Spanish single-family housing in different climate zones. The first-stage findings showed that given the system significant inertia, it discharged for several days, even when charging occurred only on the first, ensuring a wide operating range adaptable to renewable resource limitations. The analysis of potential, in turn, revealed that savings of over 40% in heating demand are possible even under the least favourable circumstances.This study was funded by Spanish Ministry of Economy and Competitiveness under the INPHASE (RTC-2015-3583-5) and DACAR (BIA2016-77431-C2-2-R), the European Regional Development Fund (ERDF) and the University of Seville under its Research Plan VI (VPPI-US). Prof. Cabeza would like to thank the Catalan Government for the quality accreditation given to her research group GREiA (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme