Gold's hedging and safe haven properties for European stock and bond markets

Most portfolio managers and risk managers strive to pick assets that lead to efficient financial risk mitigation; among them, gold stands out. This paper provides new insights into the role of gold as both a hedge and a safe haven towards European stock and sovereign bond markets. We base the analysis on evidence spanning the Euro's inception to the COVID-19 pandemic spread across Europe. To capture gold's hedge ability, we use the ADCC-GARCH and DCC-GARCH models, while for testing gold's safe haven property we use OLS regressions for different quantiles. Our results show that gold is a hedge for stocks, particularly after the Lehman Brothers collapse. Gold also shows strong safe haven properties for the most extreme negative returns (1% and 2.5% quantiles), and during specific events, such as the Lehman Brothers collapse, the Greek bailout and the Brexit Referendum. Still, for the COVID-19 pandemic outbreak, the results do not confirm this property. Conversely, for bonds, both hedge and safe haven effects are not strongly evident, with gold characterised, at best, as a weak hedge and safe haven. These findings have portfolio allocation implications for investors in European markets, namely fund and risk managers, by pointing out gold hedging and safe haven attributes.info:eu-repo/semantics/publishedVersio

Dashboard para monitorizar falhas de energia numa rede elétrica inteligente

With the appearance of smart grid and smart meters, the need to create technological solutions that allow energy distributors to monitor events and communicate with meters installed in the smart grid, has been increasing. Considering the above, and to help the events monitoring and the communications in the grid, specifically the power failures, this research has as main objective to build a dashboard to monitor outages in a smart grid. For this purpose, a specialized company in the electrical sector was selected to apply and validate the dashboard. The CRISP-DM methodology was adopted, and it is focused on the business and require systematic interaction with business experts. Based on the literature about performance indicators in the electrical sector and dashboard's, and considering several interviews conducted with a specialist, metrics and performance indicators were defined. The graphics to include in the dashboard which are appropriate to the objectives and to the problem have also been defined. To evaluate the dashboard's usefulness and usability, a questionnaire was drawn up and then applied to a specialist in this area. It was possible to conclude that the tactical dashboard, with monthly and weekly views, is useful and easy to use. Thus, with this investigation, the companies win a dashboard to be incorporated into their commercial solutions and to be used by their customers. In addition, this dashboard presents a set of indicators to be monitored in the sector of energy distribution and demonstrates the suitability of the CRISP-DM methodology for the creation of dashboard's.info:eu-repo/semantics/acceptedVersio

Progenitor properties of type II supernovae: fitting to hydrodynamical models using Markov chain Monte Carlo methods

The progenitor and explosion properties of type II supernovae (SNe~II) are fundamental to understanding the evolution of massive stars. Particular attention has been paid to the initial masses of their progenitors, but despite the efforts made, the range of initial masses is still uncertain. Direct imaging of progenitors in pre-explosion archival images suggests an upper initial mass cutoff of $\sim$18~\ms. However, this is in tension with previous studies in which progenitor masses inferred by light-curve modelling tend to favour high-mass solutions. Moreover, it has been argued that light-curve modelling alone cannot provide a unique solution for the progenitor and explosion properties of SNe II. We develop a robust method which helps us to constrain the physical parameters of SNe~II by simultaneously fitting their bolometric light curve and the evolution of the photospheric velocity to hydrodynamical models using statistical inference techniques. We created pre-supernova red supergiant models using the stellar evolution code MESA, varying the initial progenitor mass. We then processed the explosion of these progenitors through hydrodynamical simulations, where we changed the explosion energy and the synthesised nickel mass together with its spatial distribution within the ejecta. We compared the results to observations using Markov chain Monte Carlo methods. We apply this method to a well-studied set of SNe with an observed progenitor in pre-explosion images and compare with results in the literature. Progenitor mass constraints are found to be consistent between our results and those derived by pre-SN imaging and the analysis of late-time spectral modelling. We have developed a robust method to infer progenitor and explosion properties of SN II progenitors which is consistent with other methods in the literature. Our results show that hydrodynamical modelling can be used to accurately constrain the physical properties of SNe~II. This study is the starting point for a further analysis of a large sample of hydrogen-rich SNe.Fil: Martinez, Laureano. Universidad Nacional de Río Negro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Bersten, Melina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Anderson, J. P.. European Southern Observatory Chile.; ChileFil: González Gaitán, S.. Centro de Astrofísica E Gravitaçäo; PortugalFil: Förster, F.. Centro de Modelado Matemático; ChileFil: Folatelli, Gaston. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentin

Molecular Microbial Analysis of Lactobacillus Strains Isolated from the Gut of Calves for Potential Probiotic Use

The intestinal microbiota has an influence on the growth and health status of the hosts. This is of particular interest in animals reared using intensive farming practices. Hence, it is necessary to know more about complexity of the beneficial intestinal microbiota. The use of molecular methods has revolutionized microbial identification by improving its quality and effectiveness. The specific aim of the study was to analyze predominant species of Lactobacillus in intestinal microbial ecosystem of young calves. Forty-two lactic acid bacteria (LAB) isolated from intestinal tract of young calves were characterized by: Amplified Ribosomal DNA Restriction Analysis (ARDRA), by using Hae III, Msp I, and Hinf I restriction enzymes, and 16S rDNA gene sequencing. ARDRA screening revealed nine unique patterns among 42 isolates, with the same pattern for 29 of the isolates. Gene fragments of 16S rDNA of 19 strains representing different patterns were sequenced to confirm the identification of these species. These results confirmed that ARDRA is a good tool for identification and discrimination of bacterial species isolated from complex ecosystem and between closely related groups. This paper provides information about the LAB species predominant in intestinal tract of young calves that could provide beneficial effects when administered as probiotic

Comparison of the optical light curves of hydrogen-rich and hydrogen-poor type II supernovae

Type II supernovae (SNe II) show strong hydrogen features in their spectra throughout their whole evolution, while type IIb supernovae (SNe IIb) spectra evolve from dominant hydrogen lines at early times to increasingly strong helium features later on. However, it is currently unclear whether the progenitors of these SN types form a continuum in pre-SN hydrogen mass or whether they are physically distinct. SN light-curve morphology directly relates to progenitor and explosion properties such as the amount of hydrogen in the envelope, the pre-SN radius, the explosion energy, and the synthesized mass of radioactive material. In this work, we study the morphology of the optical-wavelength light curves of hydrogen-rich SNe II and hydrogen-poor SNe IIb to test whether an observational continuum exists between the two. Using a sample of 95 SNe (73 SNe II and 22 SNe IIb), we define a range of key observational parameters and present a comparative analysis between both types. We find a lack of events that bridge the observed properties of SNe II and IIb. Light-curve parameters such as rise times and post-maximum decline rates and curvatures clearly separate both SN types and we therefore conclude that there is no continuum, with the two SN types forming two observationally distinct families. In the V band a rise time of 17 d (SNe II lower and SNe IIb higher), and a magnitude difference between 30 and 40 d post-explosion of 0.4 mag (SNe II lower and SNe IIb higher) serve as approximate thresholds to differentiate both types.Fil: Pessi, Priscila Jael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Folatelli, Gaston. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Anderson, J. P.. European Southern Observatory Chile.; ChileFil: Bersten, Melina Cecilia. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Burns, C.. Observatories Of The Carnegie Institution For Science; Estados UnidosFil: Contreras, C.. Las Campanas Observatory; Chile. Space Telescope Science Institute; Estados UnidosFil: Davis, S.. Florida State University; Estados UnidosFil: Englert Urrutia, Brenda Nahir. Ministerio de Ciencia. Tecnología e Innovación Productiva. Agencia Nacional de Promoción Científica y Tecnológica; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Hamuy, M.. Universidad de Chile; ChileFil: Hsiao, Eric. Florida State University; Estados UnidosFil: Martinez, Laureano. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Morrell, Nidia Irene. Las Campanas Observatory; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Phillips, M. M.. Las Campanas Observatory; ChileFil: Suntzeff, N.. Texas A&M University; Estados UnidosFil: Stritzinger, M. D.. University Aarhus; Dinamarc

Carnegie Supernova Project: Kinky i-band light curves of Type Ia supernovae

We present detailed investigation of a specific i-band light-curve feature in Type Ia supernovae (SNe Ia) using the rapid cadence and high signal-to-noise ratio light curves obtained by the Carnegie Supernova Project. The feature is present in most SNe Ia and emerges a few days after the i-band maximum. It is an abrupt change in curvature in the light curve over a few days and appears as a flattening in mild cases and a strong downward concave shape, or a 'kink', in the most extreme cases. We computed the second derivatives of Gaussian Process interpolations to study 54 rapid-cadence light curves. From the second derivatives we measure: (1) the timing of the feature in days relative to i-band maximum; tdm2(i) and (2) the strength and direction of the concavity in mag d-2; dm2(i). 76 per cent of the SNe Ia show a negative dm2(i), representing a downward concavity - either a mild flattening or a strong 'kink'. The tdm2(i) parameter is shown to correlate with the colour-stretch parameter sBV, a SN Ia primary parameter. The dm2(i) parameter shows no correlation with sBV and therefore provides independent information. It is also largely independent of the spectroscopic and environmental properties. Dividing the sample based on the strength of the light-curve feature as measured by dm2(i), SNe Ia with strong features have a Hubble diagram dispersion of 0.107 mag, 0.075 mag smaller than the group with weak features. Although larger samples should be obtained to test this result, it potentially offers a new method for improving SN Ia distance determinations without shifting to more costly near-infrared or spectroscopic observations.Fil: Pessi, Priscila Jael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Hsiao, E. Y.. Florida State University; Estados UnidosFil: Folatelli, Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Anderson, J. P.. European Southern Observatory Santiago; ChileFil: Burns, C. R.. No especifíca;Fil: Uddin, S.. Texas A&M University; Estados UnidosFil: Galbany, L.. Consejo Superior de Investigaciones Científicas; EspañaFil: Phillips, M. M.. No especifíca;Fil: Morrell, N.. No especifíca;Fil: Ashall, C.. University of Hawaii at Manoa; Estados UnidosFil: Baron, E.. No especifíca;Fil: Contreras, C.. No especifíca;Fil: Hamuy, M.. Texas A&M University; Estados UnidosFil: Hoeflich, P.. Florida State University; Estados UnidosFil: Krisciunas, K.. Texas A&M University; Estados UnidosFil: Kumar, S.. Florida State University; Estados UnidosFil: Lu, J.. Florida State University; Estados UnidosFil: Martinez, Laureano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Piro, A. L.. No especifíca;Fil: Shahbandeh, M.. Florida State University; Estados UnidosFil: Stritzinger, M. D.. University Aarhus; DinamarcaFil: Suntzeff, N. B.. Texas A&M University; Estados Unido

Relationship Between Biogenic Amines and Free Amino Acid Contents of Winesand Musts from Alentejo (Portugal)

The concentration of biogenic amines and free amino acids was studied in 102 Portuguese wines and 18 musts from Alentejo demarcated (D.O.C.) regions. Most wines were commercial, except for 38 monovarietals obtained by micro vinification. Musts from the varieties used to produce the latter wines were also studied. Both biogenic amines and free amino acids were analyzed by HPLC using fluorescence detection for their o-phthalaldehyde/fluorenylmethyl chloroformate (OPA/FMOC) derivatives. The most significant amines (average 10.8 mg/L for histamine+tyramine in red, and 7.4 mg/L for white wines) were found to be present at low levels and, although no important relationship between each individual biogenic amine could be obtained, the total amine content depends significantly on the assimilable amino acid content in wine

Smart cities in a smart world

Very often the concept of smart city is strongly related to the flourishing of mobile applications, stressing the technological aspects and a top-down approach of high-tech centralized control systems capable of resolving all the urban issues, completely forgetting the essence of a city with its connected problems. The real challenge in future years will be a huge increase in the urban population and the changes this will produce in energy and resource consumption. It is fundamental to manage this phenomenon with clever approaches in order to guarantee a better management of resources and their sustainable access to present and future generations. This chapter develops some considerations on these aspects, trying to insert the technological issues within a framework closer to planning and with attention to the social impact

Yeasts and wine off-flavours: a technological perspective

Review article. Part of the special issue "Wine microbiology and safety: from the vineyard to the bottle (Microsafety Wine)", 19-20 Nov. 2009, ItalyIn wine production, yeasts have both beneficial and detrimental activities. Saccharomyces cerevisiae is the yeast mainly responsible for turning grape juice into wine but this species and several others may also show undesirable effects in wines. Among such effects, technologists are particularly concerned with the production of offflavours that may occur during all stages of winemaking. Typical spoiling activities include the production of ethyl acetate by apiculate yeasts before fermentation, hydrogen sulphide by S. cerevisiae during fermentation phases, acetaldehyde by film-forming yeasts during bulk storage, and volatile phenols by Dekkera bruxellensis during storage or after bottling. The occurrence of these hazards depends on the technological operations designed to obtain a given type of wine and most can be avoided by current preventive or curative measures. On the contrary, good manufacturing practices must be strengthened to deal with the problem of volatile phenol production in red wines. Appropriate monitoring of D. bruxellensis populations and quantification of 4-ethylphenol is advised during storage, particularly when oak barrels are used, and absence of viable cells must be guaranteed in bottled wines. This work, which is based on our experience at winery level, aims to provide information on appropriate technological strategies to deal with the problem of off-flavours produced by yeasts