Firms vs. insiders as traders of last resort

We explore the role of corporate insiders vs. firms as traders of last resort. We develop a simple model of insider trading in which insiders provide price support, as well as liquidity, in security markets. Consistent with the model predictions we find that in the US markets insiders’ trading activities have a clear impact on return distributions. Furthermore, we provide empirical evidence on insiders transactions and firm transactions affecting returns in a different manner. In particular, while insiders’ transactions (both purchases and sales) have a strong impact on skewness in the short run and to a lesser extent in short run volatility, company repurchases only have a clear impact on volatility, both in the short and the long run. We provide explanations for this asymmetry.Insider trading, liquidity, short-horizon variance, autocorrelation, skewness

Invasive species in Balearic Islands: use of antioxidant biomarkers in marine organism in invasive events.

Abstract not availabl

Espècies invasores a la Mar Balear: impactes sobre les comunitats marines litorals

Espècies invasores a la Mar Balear: impactes sobre les comunitats marines litoral

Anthropogenic effects on digestive gland of Pinna nobilis using oxidative stress biomarkers

The fan mussel Pinna nobilis L. is the largest endemic bivalve in the Mediterranean Sea under strict protection. The aim was to determine the effects of anthropogenic activity on antioxidant and oxidative stress biomarkers in digestive gland of P. nobilis. Antioxidant enzyme activities and protein oxidation were significantly increased in mussels sampled in the impacted area. The anthropogenic activities induced a situation of oxidative stress in P. nobilis, resulting in an antioxidant response and in an increased protein oxidatio

L'educació a les Illes Balears

La educación en las Islas Baleare

Alterations in biochemical parameters of the freshwater fish, Alburnus mossulensis, exposed to sub-lethal concentrations of Fenpropathrin

Fenpropathrin is a new pyrethroid insecticide used to control crop pests. The aim of this study was to evidence fenpropathrin-induced oxidative stress and alterations in biochemical parameters in the freshwater fish, Alburnus mossulensis. Total antioxidant capacity, malondialdehyde (MDA), catalase activity (CAT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatine phosphokinase (CK), acetylcholinesterase (AChE) in the whole body extract were measured in A. mossulensis after exposure to sub-lethal concentrations of fenpropatrin (approximately equal to 1, 2, 3, 5 and 10% of 96 h LC50) for 15 days. The 24, 48, 72 and 96 h LC50 of the fenpropathrin for A. mossulensis was 562.28±45.19, 218.18±18.75, 136.18±11.90 and 121.38±11.84 µg/L at 24±2 °C. Exposure to 2.75, 5.50 and 12.6 µg/L fenpropathrin significantly increased AST activity in fish. A significant increase in the ALP and LDH activities was observed in fish after a 15 day exposure to 1.25, 5.50 and 12.60 µg/L fenpropathrin. Fenpropatrin significantly induced lipid peroxidation and increased MDA levels in fish. Compared with the control group, total protein levels in fish decreased after exposure to 2.75, 5.50 and 12.60 µg/L fenpropathrin on day 15. Total antioxidant capacity, AChE and CPK activities in fish exposed to fenproparthin were significantly lower than control group.  There was a significant increase in the CAT and ALT activities in fish after exposure to 5.50 and 12.60 µg/L fenpropathrin. In conclusion, fenpropathrin has the potential to disrupt biochemical parameters in A. mossulensis and to induce oxidative stress

Los planes de seguimiento en los parques naturales gestionados por la Diputación de Barcelona

El Área de Espacios Naturales de la Diputación de Barcelona gestiona una docena de este tipo de espacios ubicados en el entorno de la región metropolitana de Barcelona, con una superficie protegida de más de cien mil hectáreas. Es necesario un exhaustivo conocimiento de los principales componentes de los sistemas naturales, así como de los procesos y dinámicas que están siguiendo, para poder evaluar adecuadamente la planificación y la gestión de acuerdo con los objetivos de conservación planteados. Para ello se pusieron en marcha, hace ya más de diez años, los programas de seguimiento del medio físico, natural y socioeconómico, con los que pretende detectar y analizar los principales cambios y tendencias en el tiempo. Tras una primera etapa enfocada en la obtención de información básica, en la actualidad se llevan a cabo numerosos proyectos estrechamente vinculados con la gestión, y que tienen una aplicación directa en la política de protección. El presente artículo resume cuatro planes de conservación y seguimiento

Biological effects of PAHs and heavy metals in Mytilus galloprovincialis: Assessment of the petrochemical industry in the Sicilian Coast, Italy

The use of biomarkers to analyze the effects of exposure to chemical contaminants in the aquatic environment is more extended nowadays. Mussels are sedentary filter-feeding organisms which may be exposed to large amounts of chemical pollutants. Mussels are prone to bioaccumulation and magnification of contaminants. In the present work, biological effects of environmental pollution were evaluated, mainly related to presence of PAHs and heavy metals, through several antioxidants and detoxification biomarkers in mussels (Mytilus galloprovincialis) from three areas located in the Eastern coastline of Sicily (Italy), previously transplanted (active biomonitoring). One of these three areas corresponds to the industrial harbour area between Augusta and Priolo, considered one of the most extensive areas of petrochemical industrial activity in Europe, severely contaminated by PAHs and heavy metals; a second point is located in Brucoli, littoral zone where the presence of xenobiotics in the environment is considered negligible; and a third point (reference site) from which proceed the pristine population of M. galloprovincialis. Changes at molecular and biochemical level in the tissue of the digestive gland were quantified. The results showed a significant increase (p<0.05) in the activity of the antioxidant enzyme catalase, the activity and expression of the detoxifying enzyme glutathione-S-transferase, and malondialdehyde levels, as a marker of lipid peroxidation, in mussels from the area of Priolo. The metallothioneins (MTs) gene expression was significantly induced in mussels (p<0.05) from Priolo when compared to those from the reference site. AChE was negatively affected by pollutants evidencing a decreased activity in Priolo (p<0.05). No significant differences were observed between the three sampling sites in the expression of the CYP3A1. In conclusion, the observed results demonstrate that the pollution associated with petrochemical industrial area (mainly of PAHs and heavy metals) causes the activation of the detoxification and antioxidant defence systems in the digestive gland of the mussels M. galloprovincialis, indicative of oxidative stress. This study provides further evidence of the criticality representing harbour areas, due to the presence of xenobiotics in high concentrations, which can accumulate in sediments and in living organisms due to the limited hydrodynamic inside harbour