Suchergebnisse

Las administraciones de los Parques Nacionales, Áreas Protegidas y Bienes Públicos en general deben adoptar estrategias racionales para el funcionamiento operativo y de mantenimiento. El método de los Costos de Viaje instrumentado por Krutilla y Fisher permite identificar una herramienta práctica de aplicación sensible a los efectos del Teorema de Clark por variación de los tipos sociales y financieros de descuento. El trabajo presenta una discusión instrumental sobre los métodos enunciados y una ejemplificación simulada para un Parque Nacional en Argentina.

El objetivo de este artículo es evaluar el desempeño democratizador de las candidaturas independientes en México a partir de su adopción en el año 2014. En específico, este trabajo analiza sus fundamentos jurídicos y sus requisitos legales y económicos en comparación con las candidaturas tradicionales de los candidatos de los partidos políticos. En la segunda parte del trabajo se analiza el desempeño de los candidatos independientes en los procesos electorales llevados a cabo en los años 2015, 2016 y 2017. Finalmente, se proponen algunas conclusiones que giran en torno a una cuestión central: a pesar de que las candidaturas independientes se introdujeron con la finalidad de estimular la participación ciudadana, han recibido poco apoyo electoral y, en general, han sido utilizadas de forma creciente por políticos vinculados a los partidos tradicionales que desean emprender una carrera política personal.The aim this paper is to evaluate the performance of the independent candidates in Mexico, since its legal adoption in 2014. Specifically, this paper analyses its legal foundations, the legal and the economic requirements –compared to the traditional candidacies of the political parties. The second part of the paper analyses the performance of the independent candidates in the electoral processes carried out in the years 2015, 2016 and 2017. Finally, some conclusions are proposed that revolve around a central question: although the Independents candidacies were introduced with the aim of stimulating the citizen participation, they have received generally a minor electoral support, and they have been increasingly used by politicians linked to traditional parties who wish to begin a personal political career.

El objetivo de este artículo es evaluar el desempeño democratizador de las candidaturas independientes en México a partir de su adopción en el año 2014. En específico, este trabajo analiza sus fundamentos jurídicos y sus requisitos legales y económicos en comparación con las candidaturas tradicionales de los candidatos de los partidos políticos. En la segunda parte del trabajo se analiza el desempeño de los candidatos independientes en los procesos electorales llevados a cabo en los años 2015, 2016 y 2017. Finalmente, se proponen algunas conclusiones que giran en torno a una cuestión central: a pesar de que las candidaturas independientes se introdujeron con la finalidad de estimular la participación ciudadana, han recibido poco apoyo electoral y, en general, han sido utilizadas de forma creciente por políticos vinculados a los partidos tradicionales que desean emprender una carrera política personal.The aim this paper is to evaluate the performance of the independent candidates in Mexico, since its legal adoption in 2014. Specifically, this paper analyses its legal foundations, the legal and the economic requirements –compared to the traditional candidacies of the political parties. The second part of the paper analyses the performance of the independent candidates in the electoral processes carried out in the years 2015, 2016 and 2017. Finally, some conclusions are proposed that revolve around a central question: although the Independents candidacies were introduced with the aim of stimulating the citizen participation, they have received generally a minor electoral support, and they have been increasingly used by politicians linked to traditional parties who wish to begin a personal political career.

Several nutritional studies have found a direct effect of several vitamins in chondrogenic and osteogenic development during early life stages of marine fish species. In the present study, the effect of vitamin A (VA) in gilthead sea bream skeletogenesis was evaluated by means of four different dietary regimes (enriched rotifers) containing increasing levels of total VA (75, 109, 188 and 723 ng total VA mg− 1 DW). Dietary treatments were offered to larvae during the rotifer-feeding phase (4–20 days after hatching), while later all groups were fed with Artemia nauplii and weaned onto the same inert diet. Different dietary doses of VA affected gilthead sea bream larval growth, survival, performance (maturation of the digestive system) and quality (incidence of skeletal deformities). Higher levels of dietary VA than those included in the commercial emulsion for rotifer enrichment led to different levels and typologies of skeletal deformities, indicating that gilthead sea bream larvae were very sensitive to small increases in dietary VA. The degree of ossification was affected by the level of VA in enriched rotifers: the higher amount of VA in the diet, the higher number of skeletal pieces ossified (R = 0.585, P = 0.04). Dietary VA affected the normal process of bone formation and skeletogenesis, the skeletal structures mostly affected by high amounts of dietary VA were those from the cranial skeleton (splanchnocranium), vertebral centrums and caudal fin complex. The premaxilla, maxilla and dentary bones were the cranial structures affected by dietary VA levels, resulting in a large incidence of animals with compressed snout. Dietary VA also affected the normal development of the opercular complex, and a dose–response dependant effect was observed in relation to the incidence of specimens with incomplete operculum. Body shape was also affected by the level of dietary VA, increasing the incidence of specimens with lordosis, kyphosis and/or scoliosis with the dose of VA, being the prehaemal and caudal vertebrae the most affected regions of the vertebral column with this kind of abnormalities. The caudal fin complex was the most affected region of the skeleton affected by dietary treatments as seen by the high incidence of skeletal deformities in fish fed different doses of dietary VA. Deformities affected all skeletal elements composing the caudal fin, although the most affected ones were, in order of importance, the epurals, hypurals, parahypural, neural arch and uroneurals. Differences in sensitivity to dietary VA amongst caudal fin skeletal elements might be due to their differential ontogenetic development and differences in the exposure time to VA. An excess of dietary VA also accelerated the intramembranous ossification process of vertebral centrums leading to one or two supranumerary vertebrae, and a high incidence of fused and compressed vertebral centrums. The sensibility of the developing skeletal structures to dietary VA levels should incline us to test lower doses of VA in live preys enrichments during early larval stages and higher doses afterwards. ; This work was funded by the Ministry of Education and Culture (MEC) of the Spanish Government (project AGL2005-02478). The collaboration with Y.K. (HMCR, Greece) was established thanks to the HG2004-0018 grant (MEC, Spain). I.F was supported by a predoctoral MEC fellowship and E.G. by the Programa Ramón y Cajal (MEC, Spain). ; Peer reviewed

16 páginas, 12 figuras, 4 tablas. ; The effects of different levels of vitamin A (VA) in Senegalese sole larval performance and development were evaluated by means of a dietary dose–response experiment using enriched Artemia metanauplii as a carrier of this micronutrient. Larvae were fed from 6 to 27 days post hatch (dph) with enriched Artemia containing graded levels of total VA (1.3, 2.1, 4.5 and 12.9 µg VA mg− 1 DW). The content of VA in live prey directly affected its accumulation in larvae and early juveniles. Retinyl palmitate accumulated during larval ontogeny, whereas retinol showed the opposite trend, decreasing from hatching until 41 dph and then remaining constant until the end of the study. In metamorphic larvae (10 and 15 dph), VA did not affect the number of thyroid follicles or the intensity of the immunoreactive staining of T3 and T4. However, at older stages of development (post-metamorphic larvae: 20, 30, 41 and 48 dph), VA decreased the number of thyroid follicles but increased their mean size and enhanced T3 and T4 immunoreactive staining. A dietary excess of VA did not affect either larval performance in terms of growth and survival or the maturation of the digestive system. However, the most remarkable impact of this morphogenetic nutrient was detected during skeletal morphogenesis. Dietary VA accelerated the intramembranous ossification of vertebral centrums, which led to the formation of a supranumerary haemal vertebra and a high incidence of fused and compressed vertebrae in fish fed 2.1, 4.5 and 12.9 mg VA mg− 1 DW. In addition, VA also affected those structures from vertebrae and caudal fin formed by chondral ossification, leading to defects in their shape and fusions with adjacent skeletal elements. In particular, the caudal fin was the region most affected by the dietary treatments. In order of importance, the bones with more developmental anomalies were the modified neural and haemal spines, epural, hypurals and parahypural. The impact of systemic factors such as thyroidal hormones in skeletogenesis should not be neglected since present results revealed that an excess of dietary VA affected the levels of T3 and T4, which might have affected bone formation and remodelling, leading to skeletal deformities. ; This work was funded by the Ministry of Education and Culture (MEC) of the Spanish Government (project AGL2005-02478). ; Peer reviewed