Volcanoes : why do eruptions happen?, where do they happen?

Abarca la geografía, la ciencia, y la geología para explicar los volcanes, cómo se forman, las catástrofes naturales que provocan sus erupciones y por qué cada año causan grandes daños a las personas, los bienes y al mundo natural. También hay testimonios de supervivientes. A partir de diez años.

Hurricanes and tornadoes : why do they happen?, where do they happen?

Explora el poder y la furia de los huracanes y tornados, así como los métodos de predicción y preparación para las tormentas. Proporciona una vista detallada de las catástrofes naturales, por qué ocurren y qué efecto que tienen en las comunidades locales. Visita las zonas de desastres del pasado, y descubre las zonas que están en peligro.

Astronomy.

La Astronomía estudia el universo por medio de telescopios y sondas espaciales. Se compone de diferentes disciplinas como la astrobiología, la cosmología y la astrofísica. Aquí se explica cómo ayuda a desentrañar los secretos del espacio y debatir sobre cómo empezó el universo, cuál será su final y la posibilidad de vida en otros planetas.

Carnivores.

Utilizando imágenes foto-realistas se muestran a los dinosaurios no como exhibiciones de museo sino como seres vivos. El autor es una autoridad en dinosaurios reconocida mundialmente que trae a la vida una era gobernada por reptiles y otras criaturas. En la parte inferior de algunas páginas hay una línea cronológica para situar al dinosaurio en el tiempo en que vivió en la Era Mesozoica, pero sólo ofrece una breve reseña de los diferentes períodos.

Herbivores.

Utilizando imágenes foto-realistas se muestran a los dinosaurios no como exhibiciones de museo sino como seres vivos. El autor es una autoridad en dinosaurios reconocida mundialmente que trae a la vida una era gobernada por reptiles y otras criaturas. En la parte inferior de algunas páginas hay una línea cronológica para situar al dinosaurio en el tiempo en que vivió en la Era Mesozoica, pero sólo ofrece una breve reseña de los diferentes períodos.

Fire and flood.

Una mirada detallada a las condiciones meteorológicas que provocan los incendios y las inundaciones, por qué ocurren, donde han ocurrido y qué efectos tienen sobre las comunidades locales. Examina la geografía y la historia asociada a estos desastres naturales, sus consecuencias sociales y repercusión mundial. La predicción y la prevención Abarca áreas de geografía, ciencia y geología. Ofrece también testimonios de los supervivientes. Para lectores a partir de diez años.

The hospitable desert.

Se descubren algunos aspectos de este hábitat, en el que las lluvias escasean o no existen, pero con gran abundancia de vida, tanto de plantas como de animales; y la forma en que éstos coexisten y dependen unos de otros para sobrevivir.

The urban animal.

Algunos animales han aprendido a adaptarse y prosperar en los entornos urbanos. Este volumen explora el hábitat y las costumbres de criaturas que habitan en la ciudad como, por ejemplo, insectos, aves y mamíferos. Con más de ochenta fotografías e ilustraciones, esta publicación acerca a la variedad de vida que se encuentra en jardines, casas y basureros. El texto tiene dos niveles de dificultad y dos tamaños de letra. El vocabulario del segundo nivel está pensado para lectores más expertos.

Charles I and Oliver Cromwell.

Se estudia este turbulento período de la historia británica, en el que estalla el conflicto entre la Corona y el Estado que llevó a la guerra civil. Se repasan los problemas del reinado de Carlos I, su figura como mecenas de las artes, el ascenso al poder de Oliver Cromwell, las causas de la guerra que dividió al país, así como la vida durante el período de los Estuardo y los inventos y descubrimientos de la época.

The science case for an orbital mission to Uranus: Exploring the origins and evolution of ice giant planets

Giant planets helped to shape the conditions we see in the Solar System today and they account for more than 99% of the mass of the Sun’s planetary system. They can be subdivided into the Ice Giants (Uranus and Neptune) and the Gas Giants (Jupiter and Saturn), which differ from each other in a number of fundamental ways. Uranus, in particular is the most challenging to our understanding of planetary formation and evolution, with its large obliquity, low self-luminosity, highly asymmetrical internal field, and puzzling internal structure. Uranus also has a rich planetary system consisting of a system of inner natural satellites and complex ring system, five major natural icy satellites, a system of irregular moons with varied dynamical histories, and a highly asymmetrical magnetosphere. Voyager 2 is the only spacecraft to have explored Uranus, with a flyby in 1986, and no mission is currently planned to this enigmatic system. However, a mission to the uranian system would open a new window on the origin and evolution of the Solar System and would provide crucial information on a wide variety of physicochemical processes in our Solar System. These have clear implications for understanding exoplanetary systems. In this paper we describe the science case for an orbital mission to Uranus with an atmospheric entry probe to sample the composition and atmospheric physics in Uranus’ atmosphere. The characteristics of such an orbiter and a strawman scientific payload are described and we discuss the technical challenges for such a mission. This paper is based on a white paper submitted to the European Space Agency’s call for science themes for its large-class mission programme in 2013.

Using ecological niche modelling to infer past, present and future environmental suitability for Leiopelma hochstetteri, an endangered New Zealand native frog

Leiopelma hochstetteri is an endangered New Zealand frog now confined to isolated populations scattered across the North Island. A better understanding of its past, current and predicted future environmental suitability will contribute to its conservation which is in jeopardy due to human activities, feral predators, disease and climate change. Here we use ecological niche modelling with all known occurrence data (N = 1708) and six determinant environmental variables to elucidate current, pre-human and future environmental suitability of this species. Comparison among independent runs, subfossil records and a clamping method allow validation of models. Many areas identified as currently suitable do not host any known populations. This apparent discrepancy could be explained by several non exclusive hypotheses: the areas have not been adequately surveyed and undiscovered populations still remain, the model is over simplistic; the species` sensitivity to fragmentation and small population size; biotic interactions; historical events. An additional outcome is that apparently suitable, but frog-less areas could be targeted for future translocations. Surprisingly, pre-human conditions do not differ markedly highlighting the possibility that the range of the species was broadly fragmented before human arrival. Nevertheless, some populations, particularly on the west of the North Island may have disappeared as a result of human mediated habitat modification. Future conditions are marked with higher temperatures, which are predicted to be favourable to the species. However, such virtual gain in suitable range will probably not benefit the species given the highly fragmented nature of existing habitat and the low dispersal ability of this species. (C) 2010 Elsevier Ltd. All rights reserved.

Gonad development and hormone titres in Loggerhead Sea Turtles (Caretta caretta) in the NE Atlantic

The study proposed to describe sexual development in pelagic stage loggerhead sea turtles Caretta caretta and compare this to hatchlings and adults. It is meant as an ontogenic approach, in order to understand reproductive development and population composition and their dynamics in the pelagic environment. The study focused on the pelagic loggerheads that are found in the waters offshore Madeira Island (Portugal) in the North-eastern Atlantic and use it as a developmental habitat. The innovating character of this work relied on the lack of any description regarding the gonad ontogenesis and reproductive development for the pelagic stage in any of the 7 existing sea turtle species, all of them in danger of extinction. Three methods were used to diagnose the sex of each juvenile individual and asses the level of reproductive development: (1) laparoscopy, (2) gonad biopsy and (3) the assessment of two sex steroids circulating levels, namely testosterone and estradiol. In order to cover all life stages and compare data obtained for the juvenile stage, hatchlings and nesting female adults were sampled at the nearest nesting rookery at Boa Vista Island in the Cape Verde Archipelago. Gonads from dead hatchlings were collected for gonad histology and blood was collected from nesting females for sex steroids assessment. Laparoscopies revealed to be a valid sexing method for the juvenile stage, since gonads are morphologically differentiated at these size classes. Moreover, laparoscopy was validated using gonad histology. Gonad histology of juveniles showed that gonads are already completely differentiated into ovaries or testes at the size classes examined, but development seems to be quiescent. Males present already developed seminiferous tubules with spermatogonia lining the interior of the seminiferous tubule. Female gonads present oocytes at different development stages, but only oocytes up to stage III were observed. The maximum oocyte diameter in each individual correlated with body size, suggesting that reproductive development is an on-going process in juvenile females. The circulating levels of both testosterone and estradiol in juveniles of both sexes were very low and consistently lower than the ones observed in the nesting females from Boa Vista Island. No bimodal distribution was found for any of the sex steroids analysed and thus circulating hormone levels were not a reliable tool for sexing juvenile individuals with a non-invasive technique. The ratio testosterone:estradiol did not show a bimodal distribution either. The levels of testosterone correlated with sea surface temperature. The fact that temperatures observed during this study were below 24ºC might have hindered a differential testosterone pattern between juvenile males and females. Sex ratios for this population were generated according to laparoscopy results and compared among years and size classes. An overall sex ratio of 2 females for each male was found, but they varied among size classes but not among years. Possible causes for the sex ratios observed are discussed. This study is a contribution to our knowledge on the pelagic stage of loggerhead turtles, namely on the population structure regarding sex ratio, which is a vital tool for implementing conservation strategies.