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Cochabamba, Bolivia

Sedo J.,Research Center en Nanociencia y | Saiz-Poseu J.,Valle Private University | Busque F.,Autonomous University of Barcelona | Ruiz-Molina D.,Research Center en Nanociencia y
Advanced Materials | Year: 2013

Catechols are found in nature taking part in a remarkably broad scope of biochemical processes and functions. Though not exclusively, such versatility may be traced back to several properties uniquely found together in the o-dihydroxyaryl chemical function; namely, its ability to establish reversible equilibria at moderate redox potentials and pHs and to irreversibly cross-link through complex oxidation mechanisms; its excellent chelating properties, greatly exemplified by, but by no means exclusive, to the binding of Fe 3+; and the diverse modes of interaction of the vicinal hydroxyl groups with all kinds of surfaces of remarkably different chemical and physical nature. Thanks to this diversity, catechols can be found either as simple molecular systems, forming part of supramolacular structures, coordinated to different metal ions or as macromolecules mostly arising from polymerization mechanisms through covalent bonds. Such versatility has allowed catechols to participate in several natural processes and functions that range from the adhesive properties of marine organisms to the storage of some transition metal ions. As a result of such an astonishing range of functionalities, catechol-based systems have in recent years been subject to intense research, aimed at mimicking these natural systems in order to develop new functional materials and coatings. A comprehensive review of these studies is discussed in this paper. Catechols participate in several natural processes and functions that range from the adhesive properties of marine organisms to the storage of certain metals ions. Accordingly, many scientists worldwide have been studying and mimicking these natural systems to develop new active materials and coatings. A detailed revision of a wide variety of relevant studies in this field is discussed in this Review. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diaz F.,Valle Private University | Endersby N.M.,University of Melbourne | Hoffmann A.A.,University of Melbourne
Insect Science | Year: 2015

The whitefly Bemisia tabaci (Gennadius) is one of the most important pests causing economic losses in a variety of cropping systems around the world. This species was recently found in a coastal region of Colombia and has now spread inland. To investigate this invasive process, the genetic structure of B. tabaci was examined in 8 sampling locations from 2 infested regions (coastal, inland) using 9 microsatellite markers and the mitochondrial COI gene. The mitochondrial analysis indicated that only the invasive species of the B. tabaci complex Middle East-Asia Minor 1 (MEAM 1 known previously as biotype B) was present. The microsatellite data pointed to genetic differences among the regions and no isolation by distance within regions. The coastal region in the Caribbean appears to have been the initial point of invasion, while the inland region in the Southwest showed genetic variation among populations most likely reflecting founder events and ongoing changes associated with climatic and topographical heterogeneity. These findings have implications for tracking and managing B. tabaci. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Jimenez-Esteban F.M.,CSIC - National Institute of Aerospace Technology | Jimenez-Esteban F.M.,Valle Private University | Rizzo J.R.,CSIC - National Institute of Aerospace Technology | Rizzo J.R.,European University at Madrid | Palau A.,Institute Of Ciencies Of Lespai Csic Ieec
Astrophysical Journal | Year: 2010

Aiming to perform a study of the warm dust and gas in the luminous blue variable star G79.29+0.46 and its associated nebula, we present infrared Spitzer imaging and spectroscopy, and new CO J=2→1 and 4→3 maps obtained with the IRAM 30m radio telescope and the Submillimeter Telescope, respectively. We have analyzed the nebula detecting multiple shells of dust and gas connected to the star. Using Infrared Spectrograph-Spitzer spectra, we have compared the properties of the central object, the nebula, and their surroundings. These spectra show a rich variety of solid-state features (amorphous silicates, polycyclic aromatic hydrocarbons, and CO2 ices) and narrow emission lines, superimposed on a thermal continuum. We have also analyzed the physical conditions of the nebula, which point to the existence of a photo-dissociation region. © 2010. The American Astronomical Society. All rights reserved..

Encina R.L.,Valle Private University | Alberdi M.T.,CSIC - National Museum of Natural Sciences
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen | Year: 2011

There is an abundant fossil record of the family Gomphotheriidae in Chile, which is entirely ascribed to the late Pleistocene. Despite this, the lack of taxonomically diagnostic material has lead to an extended discussion, which has not reached a consensus regarding the number of forms of gomphotheres effectively present. This paper discusses the taxonomy of Chilean gomphotheres, based on tooth morphology and biometry, paleoecological and biogeographical data. The morphology of the tusks indicates the presence of the Stegomastodon genus in Chile, while bivariate and multivariate analyses of the teeth show an important amount of variability within the studied sample, although with a tendency towards larger sizes for the genus Stegomastodon and the Chilean samples than for Cuvieronius, especially among the M3s and m3s. In spite of this, in this paper only the specimens from localities that yielded molars associated with tusks are assigned to the genus Stegomastodon. Biogeographic information is consistent with the presence of a lowland-adapted taxon such as Stegomastodon, which could have reached the Chilean territory either through an Andean corridor from Argentina, or through a low-altitude route from Peru, then by the northern region of Chile. Bibliographic isotopic data also indicates an adaptative change to C3 feeding along a latitudinal gradient, around 35-41°S, which makes the Chilean and south Argentinean results quite similar at these latitudes. Due to the metric variability observed, the Chilean samples could not be assigned to individual species. © 2011 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.

Prado J.L.,Valle Private University | Sanchez B.,CSIC - National Museum of Natural Sciences | Alberdi M.T.,CSIC - National Museum of Natural Sciences
BMC Ecology | Year: 2011

Background: Stable isotope ratios (13C/12C and 18O/16O) in fossil teeth and bone provide key archives for understanding the ecology of extinct horses during the Plio-Pleistocene in South America; however, what happened in areas of sympatry between Equus (Amerhippus) and Hippidion is less understood.Results: Here, we use stable carbon and oxygen isotopes preserved in 67 fossil tooth and bone samples for seven species of horses from 25 different localities to document the magnitude of the dietary shifts of horses and ancient floral change during the Plio-Pleistocene. Dietary reconstructions inferred from stable isotopes of both genera of horses present in South America document dietary separation and environmental changes in ancient ecosystems, including C3/C4transitions. Stable isotope data demonstrate changes in C4grass consumption, inter-species dietary partitioning and variation in isotopic niche breadth of mixed feeders with latitudinal gradient.Conclusions: The data for Hippidion indicate a preference varying from C3plants to mixed C3-C4plants in their diet. Equus (Amerhippus) shows three different patterns of dietary partitioning Equus (A.) neogeus from the province of Buenos Aires indicate a preference for C3plants in the diet. Equus (A.) andium from Ecuador and Equus (A.) insulatus from Bolivia show a preference for to a diet of mixed C3-C4plants, while Equus (A.) santaeelenae from La Carolina (sea level of Ecuador) and Brazil are mostly C4feeders. These results confirm that ancient feeding ecology cannot always be inferred from dental morphology. While the carbon isotope composition of horses skeletal material decreased as latitude increased, we found evidence of boundary between a mixed C3/C4diet signal and a pure C4signal around 32° S and a change from a mixed diet signal to an exclusively C3signal around 35°S.We found that the horses living at high altitudes and at low to middle latitude still have a C4component in their diet, except the specimens from 4000 m, which have a pure C3diet. The change in altitudinal vegetation gradients during the Pleistocene is one of several possibilities to explain the C4dietary component in horses living at high altitudes. Other alternative explanations imply that the horses fed partially at lower altitudes. © 2011 Prado et al; licensee BioMed Central Ltd.

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