Geochemical and Volcanological Criteria in Assessing the Links between Volcanism and VMS Deposits: A Case on the Iberian Pyrite Belt, Spain

VMS deposits in the Iberian Pyrite Belt (IPB), Spain and Portugal, constitute the largest accumulation of these deposits on Earth. Although several factors account for their genetic interpretation, a link between volcanism and mineralization is generally accepted. In many VMS districts, research is focused on the geochemical discrimination between barren and fertile volcanic rocks, these latter being a proxy of VMS mineralization. Additionally, the volcanological study of igneous successions sheds light on the environment at which volcanic rocks were emplaced, showing an emplacement depth consistent with that required for VMS formation. We describe a case on the El Almendro–Villanueva de los Castillejos (EAVC) succession, Spanish IPB, where abundant felsic volcanic rocks occur. According to the available evidence, their geochemical features, εNd signature and U–Pb dates suggest a possible link to VMS deposits. However, (paleo)volcanological evidence here indicates pyroclastic emplacement in a shallow water environment. We infer that such a shallow environment precluded VMS generation, a conclusion that is consistent with the absence of massive deposits all along this area. We also show that this interpretation lends additional support to previous models of the whole IPB, suggesting that compartmentalization of the belt had a major role in determining the sites of VMS depositionThis research is supported by the research project “Caracterización y datación isotópicas de rocas ígneas y sistemas hidrotermales en la Faja Pirítica Ibérica Española” (BTE2003-04354, Plan Nacional I+D) Careful revisions by anonymous reviewers have importantly contributed to improve this work and are acknowledged with than

Risk Modelling and Management: An Overview

The papers in this special issue of Mathematics and Computers in Simulation are substantially revised versions of the papers that were presented at the 2011 Madrid International Conference on “Risk Modelling and Management” (RMM2011). The papers cover the following topics: currency hedging strategies using dynamic multivariate GARCH, risk management of risk under the Basel Accord: A Bayesian approach to forecasting value-at-risk of VIX futures, fast clustering of GARCH processes via Gaussian mixture models, GFC-robust risk management under the Basel Accord using extreme value methodologies, volatility spillovers from the Chinese stock market to economic neighbours, a detailed comparison of Value-at-Risk estimates, the dynamics of BRICS's country risk ratings and domestic stock markets, U.S. stock market and oil price, forecasting value-at-risk with a duration-based POT method, and extreme market risk and extreme value theory

The Rise and Fall of S&P500 Variance Futures

Modelling, monitoring and forecasting volatility are indispensible to sensible portfolio risk management. The volatility of an asset of composite index can be traded by using volatility derivatives, such as volatility and variance swaps, options and futures. The most popular volatility index is VIX, which is a key measure of market expectations of volatility, and hence also an important barometer of investor sentiment and market volatility. Investors interpret the VIX cash index as a “fear” index, and of VIX options and VIX futures as derivatives of the “fear” index. VIX is based on S&P500 call and put options over a wide range of strike prices, and hence is not model based. Speculators can trade on volatility risk with VIX derivatives, with views on whether volatility will increase or decrease in the future, while hedgers can use volatility derivatives to avoid exposure to volatility risk. VIX and its options and futures derivatives has been widely analysed in recent years. An alternative volatility derivative to VIX is the S&P500 variance futures, which is an expectation of the variance of the S&P500 cash index. Variance futures are futures contracts written on realized variance, or standardized variance swaps. The S&P500 variance futures are not model based, so the assumptions underlying the index do not seem to have been clearly understood. As variance futures are typically thinly traded, their returns and volatility are not easy to model accurately using a variety of model specifications. This paper analyses the volatility in S&P500 3-month variance futures before, during and after the GFC, as well as for the full data period, for each of three alternative conditional volatility models and three densities, in order to determine whether exposure to risk can be incorporated into a financial portfolio without taking positions on the S&P500 index itself

Risk Management of Risk under the Basel Accord: Forecasting Value-at-Risk of VIX Futures

The Basel II Accord requires that banks and other Authorized Deposit-taking Institutions (ADIs) communicate their daily risk forecasts to the appropriate monetary authorities at the beginning of each trading day, using one or more risk models to measure Value-at-Risk (VaR). The risk estimates of these models are used to determine capital requirements and associated capital costs of ADIs, depending in part on the number of previous violations, whereby realised losses exceed the estimated VaR. McAleer, Jimenez-Martin and Perez-Amaral (2009) proposed a new approach to model selection for predicting VaR, consisting of combining alternative risk models, and comparing conservative and aggressive strategies for choosing between VaR models. This paper addresses the question of risk management of risk, namely VaR of VIX futures prices. We examine how different risk management strategies performed during the 2008-09 global financial crisis (GFC). We find that an aggressive strategy of choosing the Supremum of the single model forecasts is preferred to the other alternatives, and is robust during the GFC. However, this strategy implies relatively high numbers of violations and accumulated losses, though these are admissible under the Basel II Accord

EFECTO DE LA APLICACIÓN DE ESTRADIOL Y PROGESTERONA SOBRE LA SUPERVIVENCIA EMBRIONARIA EN LLAMAS

El efecto de la aplicación de estradiol y progesterona, alrededor del momento de reconocimiento maternal de la preñez, sobre la supervivencia embrionaria, fue evaluada en 80 llamas adultas con descanso post parto ³15 días. Se les hizo una ecografía para determinar la presencia del folículo preovulatorio (³7 mm) y luego fueron sometidas a monta por un tiempo de cópula ³15 minutos. Las llamas fueron distribuidas en 4 grupos: G0, placebo;G1, 0.2mg/llama/día de estradiol; G2, 15mg/llama/día de proligestona; yG3, 0.2mg/llama/día de estradiol y 15mg/llama/día de proligestona. La administración de los compuestos se hizo el día 8 y 9 post cópula. El día de la monta fue el día 0. Se hicieron evaluaciones ecográficas el día 2 para determinar ovulación, el día 9 para medir cuerpo lúteo y los días 20, 25, 30 y 35 para observar vesícula embrionaria ypresencia del embrión. La conducta sexual fue evaluada para determinar receptividad frente al macho el día 0 y para diagnosticar gestación temprana el día 15. El porcentaje de supervivencia embrionaria entre los días 20 y 35 fuemayor en el G1 (75%), en comparación con los otros grupos: G0 (57.9%), G2 (52.6%) yG3 (55.0%), aunque sin encontrar diferencia estadística entre grupos. Por otro lado, el tamaño del cuerpo lúteo al día 9 post cópula tuvo un diámetromayor en llamas preñadas (12.8 mm) que en no preñadas (10.8 mm) al día 35. En conclusión, estos resultados indicaron que con la aplicación de estradiol entre los días 8 y 9 post cópula se presentaría unamejor respuesta sobre el porcentaje de supervivencia embrionaria en la llama.The effect of exogenous oestradiol and progesterone on embryonic survival around the period of maternal recognition of pregnancy was evaluated in 80 adult llamas with ³15 days after parturition. An ultrasound evaluation was conducted to detect a preovulatory follicle (³7mm), and then, animalswere matedwith a male for ³15 minutes of copulation time.Animals were allocated into 4 groups: G0, placebo;G1, 0.2mg/llama/day of estradiol; G2, 15mg/llama/day of proligestone, andG3, 0.2mg/llama/day of estradiol and 15 mg/llama/day of proligestone. Injection of hormones and placebo was done at days 8 and 9 after copula. Mating daywas considered as day 0. Ultrasound evaluations were done on day 2 to determine ovulation, on day 9 to measure the size of the corpus luteum, and on days 20, 25, 30 and 35 to observe the presence of the embryonic vesicle and the embryo. Sexual behaviour was evaluated to verify female receptivity on day 0 and to diagnose earlypregnancy on day15. Embryonic survival was higher in G1 (75%) as compared to other groups:G0 (57.9%), G2 (52.6%), and G3 (55.0%) until day 35, but without significant differences. The size of corpus luteumon day9was larger in pregnant (12.8mm) than in non pregnant llamas (10.8mm). In conclusion, the results suggested that the application of estradiol between days 8 and 9 aftermatingmay improve embryonic survival rate in llamas

Risk Management of Risk Under the Basel Accord: A Bayesian Approach to Forecasting Value-at-Risk of VIX Futures

It is well known that the Basel II Accord requires banks and other Authorized Deposit-taking Institutions (ADIs) to communicate their daily risk forecasts to the appropriate monetary authorities at the beginning of each trading day, using one or more risk models, whether individually or as combinations, to measure Value-at-Risk (VaR). The risk estimates of these models are used to determine capital requirements and associated capital costs of ADIs, depending in part on the number of previous violations, whereby realised losses exceed the estimated VaR. McAleer et al. (2009) proposed a new approach to model selection for predicting VaR, consisting of combining alternative risk models, and comparing conservative and aggressive strategies for choosing between VaR models. This paper addresses the question of risk management of risk, namely VaR of VIX futures prices, and extends the approaches given in McAleer et al. (2009) and Chang et al. (2011) to examine how different risk management strategies performed during the 2008-09 global financial crisis (GFC). The empirical results suggest that an aggressive strategy of choosing the Supremum of single model forecasts, as compared with Bayesian and non-Bayesian combinations of models, is preferred to other alternatives, and is robust during the GFC. However, this strategy implies relatively high numbers of violations and accumulated losses, which are admissible under the Basel II Accord

Experimental and numerical studies to assess the energy performance of naturally ventilated PV façade systems

This paper presents a holistic approach to assess the energy performance of a naturally ventilated PV façade system. A rigorous combined experimental and numerical approach is established. The real energy performance of the system has been evaluated through a long-term high resolution monitoring of a typical ventilated PV façade system. A numerical model based on TRaNsient SYstem Simulation (TRNSYS) package was developed to assess the thermal and energy performance of the system, which has been verified by a series of statistical analysis using the data collected from the experiment. The validated model was then used to assess the energy and thermal performance of a 7.4 kWp prototype ventilated PV façade system in Izmir, Turkey. The results of this study demonstrated that ventilation in the air cavity of the PV façade system could significantly improve energy performance of the system even in a southeast facing façades. The quantitative analysis provides useful guidance to the system designers for the improvement of energy efficiency of the PV facade system

Trophic ecology of common bottlenose dolphins in a pelagic insular environment inferred by stable isotopes

The common bottlenose dolphin (Tursiops truncatus) is a top marine predator widely dispersed in coastal and pelagic habitats and with a generalist feeding behavior. Yet, information on the trophic ecology of animals inhabiting pelagic environments is still scarce. Using carbon (& delta;C-13: C-13/C-12) and nitrogen (& delta;N-15: N-15/N-14) stable isotope ratios, we identified and quantified the main groups of prey assimilated by bottlenose dolphins inhabiting an oceanic habitat (Madeira Island, East Atlantic). Bottlenose dolphins assimilated pelagic, schooling fish (such as blue jack mackerel, Trachurus picturatus) and mesopelagic and demersal squids, which reinforces the pelagic dietary composition of insular/oceanic dolphins. Also, intra-seasonal differences were found in their stable isotope ratios, which suggest intraspecific variability in the feeding behavior among individuals living in the same area. Sex was not the main factor contributing to these differences, suggesting the lack of trophic niche segregation between adult males and females in this offshore environment. Nonetheless, further studies including different life stages and information on the ecophysiological requirements are necessary to disclose the factors responsible for the observed variability. This study showed that insular dolphins fed primarily on economically important pelagic prey, highlighting the need of developing management strategies that integrate conservation in fisheries plans.NORTE01-0145-FEDER-000031; M1420-01-0145-FEDER-000001-OOM; LA/P/0069/2020; M1420-09-5369-FSE-000002info:eu-repo/semantics/publishedVersio

TASA DE OVULACIÓN UTILIZANDO LIBERADOR DE GONADOTROPINAS Y PLASMA SEMINAL EN ALPACAS Y LLAMAS

The aim of the present study was to determine the ovulation rate using GnRH (buserelin) and seminal plasma of alpaca as ovulation inductors in alpacas and llamas. For this, 93 alpacas and 92 llamas were distributed in two groups: a group treated with buserelin (42 μg) IM, and a group treated with 1 ml of seminal plasma IM (50/50% seminal plasma of alpaca and PBS + antibiotics). The ovulation rate was 78.7 and 88.9% in alpacas and 80.6 and 70.0% in llamas using buserelin and seminal plasma respectively; and without statistical differences due to type of ovulation inductor, ovary carrying the preovulatory follicle or species.Se trabajó con 93 alpacas y 92 llamas a fin de determinar el porcentaje de ovulación utilizando GnRH (buserelina) y plasma seminal de alpaca como inductor de ovulación en alpacas y llamas. Los animales se distribuyeron en dos grupos, un grupo tratado con 42 μg de buserelina intramuscular y otro grupo tratado con 1 ml de plasma seminal intramuscular (50/50% de plasma seminal y PBS + antibióticos). La tasa de ovulación fue de 78.7 y 88.9% en alpacas y 80.6 y 70.0 en llamas con buserelina y plasma seminal, respectivamente, no encontrándose diferencias estadísticas entre tipo de inductor, ovario con presencia de folículo preovulatorio o especie

Serum tryptase monitoring in indolent systemic mastocytosis: association with disease features and patient outcome

This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al.[Background]: Serum baseline tryptase (sBT) is a minor diagnostic criterion for systemic mastocytosis (SM) of undetermined prognostic impact. We monitored sBT levels in indolent SM (ISM) patients and investigated its utility for predicting disease behaviour and outcome. [Methods]: In total 74 adult ISM patients who were followed for ≥48 months and received no cytoreductive therapy were retrospectively studied. Patients were classified according to the pattern of evolution of sBT observed. [Results]: Overall 16/74 (22%) cases had decreasing sBT levels, 48 (65%) patients showed increasing sBT levels and 10 (13%) patients showed a fluctuating pattern. Patients with significantly increasing sBT (sBT slope ≥0.15) after 48 months of follow-up showed a slightly greater rate of development of diffuse bone sclerosis (13% vs. 2%) and hepatomegaly plus splenomegaly (16% vs. 5%), as well as a significantly greater frequency of multilineage vs. mast cells (MC)-restricted KIT mutation (p = 0.01) together with a greater frequency of cases with progression of ISM to smouldering and aggressive SM (p = 0.03), and a shorter progression-free survival (p = 0.03). [Conclusions]: Monitoring of sBT in ISM patients is closely associated with poor prognosis disease features as well as with disease progression, pointing out the need for a closer follow-up in ISM patients with progressively increasing sBT values.This work was supported by grants from the Fondo de Investigaciones Sanitarias (FIS) of the Ministerio de Ciencia e Innovación of Spain (RETICS RD06/0020/0035-FEDER and PS09/00032); Fundación Sociosanitaria de Castilla-La Mancha (FISCAM 2007/36, FISCAM 2010/008 and G-2010/C-002); Instituto de Salud Carlos III of the Ministerio de Economía y Competitividad of Spain (PI11/02399); Junta de Castilla y León (SAN/103/2011); Fundación Ramón Areces; Fundación Española de Mastocitosis (FEM 2010); Hospital Virgen de la Salud Biobank (BioB-HVS) supported by grant of RETICS RD09/0076/00074, (Toledo, Spain).Peer Reviewe