La Inversión francesa en la canalización del Ebro: de la navegación al riego (1848-1904)

La Real Compañía de Canalización del Ebro, sociedad anónima constituida en 1852 con un capital nominal de 31,5 millones de pesetas, que tenía como objetivo fundamental abrir el Ebro a la navegación a vapor en base a un proyecto técnico elaborado por ingenieros franceses, tuvo que recurrir a inversores europeos para levantar su capital. Se trataría, pues, de una empresa equiparable en muchos aspectos –inversión en comunicaciones, elevado capital, dependencia de técnicos e inversores europeos– a las grandes compañías ferroviarias constituidas en España a mediados del siglo XIX. El fracaso en la navegación reorientó su actividad hacia el riego, siendo la empresa encargada de construir y explotar hasta 1966 estas infraestructuras en el Delta del Ebro. En este texto, después de referirnos a los diferentes intentos de canalización del Ebro relacionados con la navegación hasta mediados de siglo XIX, analizaremos los motivos de su evolución y la diferente actitud mantenida ante las oportunidades de negocio por los dos grandes sectores de accionistas, el capital catalán y el capital francés, hasta la salida de este último ocurrida entre 1878 y 1904. Asimismo, intentaremos mostrar como el ritmo de la inversión en la canalización se ajusta al de la inversión francesa en España, que iniciada en el siglo XVIII, se paraliza con la crisis del Antiguo Régimen, se intensifica a partir de la década de 1840 orientándose mayoritariamente hacia los sectores ferroviario y minero, e inicia un cierto repliegue a partir de la última década del siglo XIX.

Itinerari polític i ideològic de Ferran Valls-Taberner : de la República al franquisme (1931-1942)

Ferran Valls-Taberner fou un intel•lectual i polític que va militar a la Lliga Regionalista durant més de vint-i-sis anys i després es va convertir en un ideòleg del franquisme. En aquest treball s'estudien les raons que el van portar a fer aquest canvi a partir dels llibres i articles que va publicar.

Introduction and spreading of Biomphalaria straminea (Dunker, 1848) (Mollusca: Pulmonata: Planorbidae) in Guadeloupe, French West Indies

The finding in 1985 of a well-established population of Biomphalaria straminea in a pond in Grande Terre of Guadeloupe constitutes a new species record for the freshwater molluscan fauna of that island. The following years a rapid extension of the species was documented on Grande Terre and Marie Galante. However, it was never found in the neighboring island of Basse Terre. The invasion of the whole hydrographic system of this island by Melanoides tuberculata during the last decade and the current presence of well-established and dense populations of this snail may explain the failure of the colonization by B. straminea.

Evaluation of Chemical and Physical-morphological Factors as Potential Determinants of Biomphalaria pfeifferi (Krauss, 1848) Distribution

This study was carried out in five sites along a small perennial river system in south-central Tanzania, which had been identified as the focus for transmission of intestinal schistosomiasis in the area. Malacological surveys preceding the study showed a focal distribution of Biomphalaria pfeifferi, intermediate host snail of Schistosoma mansoni, the snails being present in three sites but absent from the other two sites. The objective of this study was to evaluate to what extent chemical and/or physical-morphological factors determine the distribution of B. pfeifferi between these five sites. It was found that none of the chemical constituents in the waters examined were outside the tolerance range of B. pfeifferi snails. Moreover, the composition of water from B. pfeifferi-free sites was not different from that in those sites where snails occurred. Furthermore, none of the physical-morphological constituents seemed likely to be a determinant for the absence of B. pfeifferi. In view of these findings, and those of previous studies, it is concluded that the focal distribution of B. pfeifferi cannot be associated with a single environmental factor and is rather the result of more complex interactions of habitat factors

Paraorientatractis semiannulata n. g., n. sp. (Cosmocercoidea: Atractidae) from the Large Intestine of the SideNecked Turtle, Podocnemis unifilis Troschel, 1848 (Testudines: Pelomedusidae) in Brazil

Specimens collected from the large intestine of the sidenecked turtle Podocnemis unifilis Troschel, 1848 in the region of Cuminá and Trombetas rivers near Pará, Brazil are assigned to a new genus and new species of the nematode superfamily Cosmocercoidea and family Atractidae and named Paraorientatractis semiannulata. The new genus is separated from the nearest genus Orientatractis by the funnelshaped mouth opening, the presence of 4 distinct lips, 4 papillae in the internal cycle, one on each lip margin, 2 lateral amphids with large amphidial pores and absence of submedian papillae. It is also separated from Orientatractis and Proatractis by the presence of striated lateral alae which curve dorsally extending from mid oesophagus to mid tail, the difference in size of the vulvar opening and the presence of large transverse ridges or semiannules on the dorsal surface. The new species can be separated from the species of the genera Orientatractis and Proatractis by the characters that distinguish the genera and the arrangement of the caudal papillae on the male. A host/parasite list for Podocnemis spp. is included

Fecundity Changes Induced by Low-Doses of Gamma Radiation on Biomphalaria straminea (Dunker, 1848)

A population of 420 snails Biomphalaria straminea, an intermediate host of Schistosoma mansoni, received gamma-rays obtained from a 60Co source in low-doses (0/2,5/5/7,5/10/15/20 and 25 Gy); half population was kept in colonies (allowing cross fertilization) and the other half was mantained in sexual isolation (allowing self fertilization). Results showed that 15 Gy stimulates the fertility of both groups but the colonies were more sensitive and at this dose its fertility overpasses the control group dose. The possible hormonal role played in the observed phenomena is under investigation

Growth changes induced by gamma radiation on Biomphalaria straminea (Dunker, 1848)

Doses of 60Co gamma radiation with 2.5; 5; 7.5; 10; 15; 20; 25; 30; 35; 40; 45; 50; 55; 60; 80; 160; 320 and 640 Gy were applied to 1,080 snails Biomphalaria straminea, an intermediate host of Schistosoma mansoni, divided in groups containing 30 mollusks. In addition, 60 non irradiated snails were kept as control. Fifty percent of the population was kept in colonies (allowing cross fertilization) while the other half was maintained in sexual isolation (allowing self fertilization) and during one month their growth was observed through the daily measurement of the shell diameter. Results showed that after 20 Gy doses the growth in shell diameter of irradiated snails was greater than that of the control group after 30 days. At this dose the snail size was the greatest, among all isolated groups. The 80 Gy doses also induced the final shell diameter of isolated snails to be greater then that observed in the control groups. As this effect was most evident among the isolated snails, a possible hormonal role may have been involved in the observed phenomena, which is under investigation with the objective of identifying any future applications that this could have to schistosomiasis control.

Infection by Schistosoma mansoni sambon 1907 in the first four months of life of Biomphalaria straminea (Dunker, 1848) in Brazil

Compatibility between Schistosoma mansoni and Biomphalaria straminea when exposed to the parasite on the first four months of age was assessed for five parasitological aspects: indices of infection and mortality, duration of precercarial and cercarial periods, and rate of cercarial emission. Infections were made on molluscs from laboratory colonies, at the following ages: 8, 13, 18, 21, 53, 83 and 114 days. Two B. straminea colonies were used (Camorim, PE and Picos, PI), and one B. glabrata colony (Ressaca, MG) was used as control. The main results are as follows: (I) infection was significantly associated with mollusc age, being proportionally higher in sexually immature than in mature molluscs for the three colonies; (II) for B. straminea from Camorim, mortality did not differ significantly between infected and non-infected snails; for B. straminea from Picos significantly more deaths occurred among infected than among non-infected snails, while the opposite was observed for B. glabrata from Ressaca; (III) for the three colonies, the precercarial period was significantly shorter for immature molluscs than for mature ones; (IV) the duration of the cercarial period was extremely variable for the three colonies; (V) sexual maturity did not influence cercarial emission for the three colonies.

Susceptibility of Biomphalaria straminea (Dunker, 1848) from Serra da Mesa Dam, Goiás, Brazil to infection with three strains of Schistosoma mansoni Sambon, 1907

Ecological changes from water resources development projects often affect the epidemiology of water-associated diseases. In order to investigate the occurrence and distribution of freshwater snails of medical and veterinary importance in the area of influence of the Serra da Mesa Hydroelectric a survey has been performed since 1997 and revealed the occurrence of well-established populations of Biomphalaria straminea (Dunker, 1848) in the 8 municipalities surrounding the lake. Areas of epidemiologic risk for schistosomiasis were selected and studies of parasite-mollusc compatibility were undertaken using specimens from 19 populations of B. straminea and 3 strains (CM, EC and PB) originally isolated from B. straminea. Among 1,135 specimens used 15 became infected (infection index of 1.3%) and 8 populations were susceptible to the schistosome strains: B. straminea from Campinorte (Castelão, susceptible to CM and EC strains, and Planeta Água, EC strain), Colinas (Tocantinzinho river, CM and EC strains), Minaçu (Canabrava river, EC strain), Niquelândia (Codemin, CM and PB strains, and Almas river, CM strain), Uruaçu (touristic area, PB strain) and Santa Rita do Novo Destino (Maranhão river, CM and EC strains). These results, associated with marked social and ecological changes occurred, strongly suggest the possibility of B. straminea coming to act as a vector of schistosomiasis in the studied area.

Biological aspects of crosses between Triatoma maculata (Erichson, 1848) and Triatoma pseudomaculata Corrêa & Espínola, 1964 (Hemiptera: Reduviidae)

Due to morphological similarities between Triatoma maculata and T. pseudomaculata, which comprise the "maculate complex", both had been regarded as the same species until 1964. Considering that the studies on triatomine hybridization permit hypotheses formulation concerning origin and divergence of species, enabling a quantitative analysis of taxonomic relationships between species, the present investigation was aimed at broadening further understanding related to the capacity of hybrid production by determining the degree of reproductive isolation between T. maculata and T. pseudomaculata. Our results have demonstrated that T. maculata and T. pseudomaculata showed no differences regarding reproduction patterns and they are able to cross, generating infertile hybrids.