University of Alcalá

About: University of Alcalá is a education organization based out in Alcalá de Henares, Spain. It is known for research contribution in the topics: Population & Receptor. The organization has 10795 authors who have published 20718 publications receiving 410089 citations. The organization is also known as: University of Alcala & University of Alcala de Henares.

Species Distribution Modeling in the Tropics: Problems, Potentialities, and the Role of Biological Data for Effective Species Conservation:

Abstract: In this paper we aim to investigate the problems and potentialities of species distribution modeling (SDM) as a tool for conservation planning and policy development and implementation in tropical regions. We reviewed 123 studies published between 1995 and 2007 in five of the leading journals in ecology and conservation, and examined two tropical case studies in which distribution modeling is currently being applied to support conservation planning. We also analyzed the characteristics of data typically used for fitting models within the specific context of modeling tree species distribution in Central America. The results showed that methodological papers outnumbered reports of SDMs being used in an applied context for setting conservation priorities, particularly in the tropics. Most applications of SDMs were in temperate regions and biased towards certain organisms such as mammals and birds. Studies from tropical regions were less likely to be validated than those from temperate regions. Unpublished data from two major tropical case studies showed that those species that are most in need of conservation actions, namely those that are the rarest or most threatened, are those for which SDM is least likely to be useful. We found that only 15% of the tree species of conservation concern in Central America could be reliably modelled using data from a substantial source (Missouri Botanical Garden VAST database). Lack of data limits model validation in tropical areas, further restricting the value of SDMs. We concluded that SDMs have a great potential to support biodiversity conservation in the tropics, by supporting the development of conservation strategies and plans, identifying knowledge gaps, and providing a tool to examine the potential impacts of environmental change. However, for this potential to be fully realized, problems of data quality and availability need to be overcome. Weaknesses in current biological datasets need to be systematically addressed, by increasing collection of field survey data, improving data sharing and increasing structural integration of data sources. This should include use of distributed databases with common standards, referential integrity, and rigorous quality control. Integration of data management with SDMs could significantly add value to existing data resources by improving data quality control and enabling knowledge gaps to be identified.

A new fossil resin with biological inclusions in lower cretaceous deposits from álava (northern spain, basque-cantabrian basin)

Abstract: The occurrence of amber in Sierra de Cantabria (Alava, Basque Country) has been known for more than two decades but biological inclusions have only recently been found. The existence of crustaceans (amphipods and isopods), chelicerates (acari and arachnids), 12 orders of insects, and several bird feathers are reported in this preliminary study. In addition, there are leaf remains, molluscs, and a fair number of inorganic inclusions. Pollen analysis of the clastic series indicates an age between upper Aptian—middle Albian, which allows an assignment of this stratigraphic unit to the Nograro Formation. Chemical analysis indicates that the amber has high maturity, which reflects its Cretaceous age. Chemical composition analysis also indicates an araucariacean origin, which is corroborated by pollen found within the amber deposit. This new fossil site provides information for the reconstruction of paleocommunities of arthropods and sedimentary environments in the extreme south of the Basque-Cantabrian Basin during the Lower Cretaceous, characterized by coniferous forests with an understory of vascular cryptograms. Some of the identified arthropods add to the fossil record for various groups that are poorly known or unknown for this time period. This Lagerstatte constitutes one of the most important deposits of Mesozoic amber in the world.

Micromotors for environmental applications: a review

Abstract: Self-propelled micromotors represent a new paradigm in the environmental field, greatly enhancing the efficiency of traditional operations due to the actively moving matter phenomena. This review highlights current opportunities and challenges in the use of micromotors for enhancing pollutant degradation and removal, accelerating bacterial killing or enabling dynamic environmental monitoring. Such studies exemplify the wide range of potential environmental applications of dynamic micromachines associated with their continuous motion, force and functionality. We will conclude with the challenges of moving these exciting advances from the bench scale to larger-scale field applications.

The Behavior of Paracetamol in Mixtures of Amphirotic and Amphiprotic-Aprotic Solvents. Relationship of Solubility Curves to Specific and Nonspecific Interactions

Abstract: The solubility of paracetamol was studied at 25°C in mixtures of amphiprotic and aprotic solvents of varying polarity (ethyl acetate-ethanol, ethanol-water, dioxane-water). A plot of the solubility mole fraction of the drug versus the solubility parameter of the solvent mixtures reached a peak in dioxane-water, and two solubility maxima within the polarity range provided by the ethanol-water and ethanol-ethyl acetate mixtures. This "chameleonic effect" can be quantitatively described in terms of cavity formation, nonspecific and specific interactions, represented by the Hildebrand solubility parameter and the acidic and basic solubility parameters of the solvent mixtures. The model predicts two solubility maxima, as found experimentally. The behavior of paracetamol in dioxane-water mixtures is similar to that of other drugs, showing a single maximum, although a small peak and a valley are also observed near the solubility parameter region where the maximum in ethanol-water appears. An increase in the temperature of fusion of the solid phase by about eight degrees was observed after equilibration of the powder with ethanol, ethyl acetate and dioxane. No changes in the solid phase were observed in water and aqueous mixtures below 50% water. The same change in the solid phase was also found in ethanol-ethyl acetate mixtures; it was independent of the nature and cosolvent ratio and had little effect on the relative variation of solubility with solvent composition. The solid phase contributes as a constant to the total solubility.