Palynological study of the Galapagos endemic genus Darwiniothamnus (Asteraceae)

XV lnternational A.P.L.E. Symposium of Palynolog

Ultra High Resolution Transmission Electron Microscopy of Matrix Mineral Grains in CM Chondrites: Preaccretionary or Parent Body Aqueous Processing?

CM chondrites are highly hydrated meteorites associated with a parent asteroid that has experienced significant aqueous processing. The meteoritic evidence indicates that these non-differentiated asteroids are formed by fine-grained minerals embedded in a nanometric matrix that preserves chemical clues of the forming environment. So far there are two hypothesis to explain the presence of hydrated minerals in the content of CM chondrites: one is based on textural features in chondrule-rim boundaries [1-3], and the other ‘preaccretionary’ hypothesis proposes the incorporation of hydrated phases from the protoplanetary disk [4-6]. The highly porous structure of these chondrites is inherited from the diverse materials present in the protoplanetary disk environment. These bodies were presumably formed by low relative velocity encounters that led to the accretion of silicate-rich chondrules, refractory Ca- and Al-rich inclusions (CAIs), metal grains, and the fine-grained materials forming the matrix. Owing to the presence of significant terrestrial water in meteorite finds [7], here we have focused on two CM chondrite falls with minimal terrestrial processing: Murchison and Cold Bokkeveld. Anhydrous carbonaceous chondrite matrices are usually represented by highly chemically unequilibrated samples that contain distinguishable stellar grains. Other chondrites have experienced hydration and chemical homogeneization that reveal parent body processes. We have studied CM chondrites because these meteorites have experienced variable hydration levels [8-10]. It is important to study the textural effects of aqueous alteration in the main minerals to decipher which steps and environments promote bulk chemistry changes, and create the distinctive alteration products. It is thought that aqueous alteration has particularly played a key role in modifying primordial bulk chemistry, and homogenizing the isotopic content of fine-grained matrix materials [7, 11, 12]. Fortunately, the mineralogy produced by parent-body and terrestrial aqueous alteration processes is distinctive [5, 11]

Insect pollinators of Jasminocereus thouarsii, an endemic cactus of the Galapagos Islands

Jasminocereus is a columnar cactus endemic to the Galapagos Islands, and is distributed mainly in the lowland arid zones. Its only species, J. thouarsii, has several varieties on different islands. Observations of the variety J. thouarsii var. delicatus on Santa Cruz Island suggested limited recruitment. We therefore studied its floral biology, pollination requirements and seed germination to determine whether recruitment might be limited by seed production or seed quality. Flowers opened in the early morning, from 5h00 to 10h00. No seed was produced by flowers isolated in pollination bags. Pollination was allogamous, mostly brought about by the endemic Xylocopa darwini (Hymenoptera: Apidae), followed by the introduced Acrosticta apicalis (Diptera) and endemic Camponotus planus (Hymenoptera: Formicidae). Seeds germinated well, with the highest germination rate obtained from seeds that were soaked before planting

Ultra High Resolution Transmission Electron Microscopy of Matrix Mineral Grains in CM Chondrites: Preaccretionary or Parent Body Aqueous Processing?

CM chondrites are highly hydrated meteorites associated with a parent asteroid that has experienced significant aqueous processing. The meteoritic evidence indicates that these non-differentiated asteroids are formed by fine-grained minerals embedded in a nanometric matrix that preserves chemical clues of the forming environment. So far there are two hypothesis to explain the presence of hydrated minerals in the content of CM chondrites: one is based on textural features in chondrule-rim boundaries [1-3], and the other ‘preaccretionary’ hypothesis proposes the incorporation of hydrated phases from the protoplanetary disk [4-6]. The highly porous structure of these chondrites is inherited from the diverse materials present in the protoplanetary disk environment. These bodies were presumably formed by low relative velocity encounters that led to the accretion of silicate-rich chondrules, refractory Ca- and Al-rich inclusions (CAIs), metal grains, and the fine-grained materials forming the matrix. Owing to the presence of significant terrestrial water in meteorite finds [7], here we have focused on two CM chondrite falls with minimal terrestrial processing: Murchison and Cold Bokkeveld. Anhydrous carbonaceous chondrite matrices are usually represented by highly chemically unequilibrated samples that contain distinguishable stellar grains. Other chondrites have experienced hydration and chemical homogeneization that reveal parent body processes. We have studied CM chondrites because these meteorites have experienced variable hydration levels [8-10]. It is important to study the textural effects of aqueous alteration in the main minerals to decipher which steps and environments promote bulk chemistry changes, and create the distinctive alteration products. It is thought that aqueous alteration has particularly played a key role in modifying primordial bulk chemistry, and homogenizing the isotopic content of fine-grained matrix materials [7, 11, 12]. Fortunately, the mineralogy produced by parent-body and terrestrial aqueous alteration processes is distinctive [5, 11]

Dos años de estudios aerobiológicos en Vélez-Málaga (sur de España): periodo Febrero-Junio

XV lnternational A.P.L.E. Symposium of Palynolog

Simulation in Information Systems: Potential of the vulnerability theory

Systems simulation has been widely used in the last decades in order to analyze the impact of different scenarios in several areas, and its application to information systems in no exception. Analyzing information systems through simulation models is simultaneously much more affordable; it is required a smaller amount of resources and it is less disruptive with the real system. Since information systems are becoming a cornerstone for our society, a failure in these systems can have a huge impact. The theory of vulnerability identifies failures in which small damage can have disproportionate impact consequences in terms of the functionality of the whole system. This paper discusses the use of the theory of vulnerability in information system simulation

Análisis y tendencias del polen de Chenopodiáceas-Amarantáceas en la atmósfera de cuatro ciudades del sur de España

XV lnternational A.P.L.E. Symposium of Palynolog