BTZ Solutions on Codimension-2 Braneworlds

We consider five-dimensional gravity with a Gauss-Bonnet term in the bulk and an induced gravity term on a 2-brane of codimension-2. We show that this system admits BTZ-like black holes on the 2-brane which are extended into the bulk with regular horizons.Comment: 6 pages. Talk given at Recent Developments in Gravity (NEB XIII), Thessaloniki, Greece, June 4-6, 2008

Reduction of the formaldehyde content in leathers treated with formaldehyde resins by means of plant polyphenols

Formaldehyde has applications in many industrial processes, including synthesis of resins and syntans to be used in the retanning process of leather. When resins are employed, they can hydrolyse, releasing formaldehyde. Due to the carcinogenicity of formaldehyde, its presence in leather should be avoided or kept below allowable limits. The aim of this study is to determine the effect of polyphenols contained in vegetable compounds (mimosa, quebracho and tara) in the reduction of the formaldehyde content in leathers treated with resins synthesized with formaldehyde (melamine-formaldehyde and dicyandiamide-formaldehyde). The formaldehyde content in leathers treated only with resin increases with time while the formaldehyde content in leathers treated additionally with vegetable compounds is reduced. The lower the formaldehyde content in the leather, the higher the ability of vegetable compounds to reduce such content. Mimosa shows the strongest ability to reduce the formaldehyde content, and this capacity increases with ageing. The addition of 4% (on shaved wet-blue weight) of mimosa gives rise to an 85% reduction in the formaldehyde content 140 days after leather processing of split hides treated with a formaldehyde resin of low formaldehyde content. However, this reduction is 68% in splits hides treated with a resin of high formaldehyde content. This is of great importance in baby’s leather articles, in which the formaldehyde content is low; therefore, the addition of a small amount (3%) of vegetable compounds (especially mimosa) guarantees that the formaldehyde content is below the allowed limits (16 mg/kg in the most restrictive regulation). Reducing the formaldehyde content using the polyphenols contained in vegetable compounds constitutes a good alternative not only in the leather sector but also in other industrial sectors (wood, textile, etc.) that use formaldehyde resins.Peer ReviewedPostprint (published version

Weathering of the Ethiopian volcanic province: a new weathering index to characterize and compare soils

© Walter de Gruyter Berlin/Boston 2015.Soil formation occurs through numerous physical and chemical weathering processes acting to alter the parent rock on the Earths surface. Samples of surface soils were collected over a range of elevations (2000-3600 m) from profiles directly overlying basaltic to more felsic parent rocks, over a region in NW Ethiopia. The soils were investigated to determine their chemical composition and X-ray diffraction was used to identify and quantify individual mineral phases. The data set was analyzed using non-parametric statistics (Spearmans Rank and Mann-Whitney U tests) to compare the soils forming over the two parent rocks. Principal component analysis (PCA) was used to identify the mineral alteration assemblage and formation during pedogenesis. The extent of alteration was quantified using several chemical weathering indices (Chemical Index of Alteration = CIA; Chemical Index of Weathering = CIW), including an index calculated by multivariate analyses of the soil chemical composition data (weathering W index). Further to this we devised and tested a new weathering index (Wmin) using multivariate analysis of the soil mineralogy, to estimate the extent of weathering and physico-chemical proprieties of the parent rock from which the soil formed. The soils present a fair to advanced stage of alteration, with abundant iron (Fe) oxides (up to 40 wt%) and phyllosilicates (up to 57 wt%), including kaolinite-smectite (K-S) mixed-layer phases. The K-S was composed of either 30-50% kaolinite or 94-98% kaolinite layers. Discrete kaolinite was also present. The bimodal K-S mineralogical composition is likely due to two precursor phases: feldspar for the kaolinite-rich K-S and volcanic glass for the smectite-rich K-S. K-S with intermediate composition (50-94% kaolinite) was rare, due to its instability. Statistical analysis showed significant differences between the chemical compositions of the soils developed on the two different parent volcanic compositions. The soils overlying the more felsic parent rocks were less altered than those overlying the flood basalt. When comparing the weathering indices calculated in this study, we conclude that while the CIA and CIW may be more readily determined, the W and Wmin indices can elucidate information on the composition of the original rock from which they formed. The W index is more sensitive to certain variables when compared with the newly derived mineralogical Wmin index; however the Wmin index takes into account mineral phases within the sample, which provides a more detailed interpretation of weathering rates than chemistry alone. In addition the Wmin index correlated with meteorological variables, such as elevation (and consequently temperature and precipitation), known to influence the degree of pedogenesis. The Wmin index can be used to enhance our understanding of the processes that occur during weathering processes to supplement information gained from traditional chemical weathering indices

Lexical Normalization of Spanish Tweets with Rule-Based Components and Language Models

This paper presents a system to normalize Spanish tweets, which uses preprocessing rules, a domain-appropriate edit-distance model, and language models to select correction candidates based on context. The system is an improvement on the tool we submitted to the Tweet-Norm 2013 shared task, and results on the task's test-corpus are above-average. Additionally, we provide a study of the impact for tweet normalization of the different components of the system: rule-based, edit-distance based and statistical

Local knowledge of native potato (Solanum spp) for long-term monitoring on three Andean Communities of Apurimac, Peru.

Multiple drivers related to changes in climate and socio-cultural structure in the Peruvian Highland are of increasing importance for the loss of the biological diversity of potato landraces and related collective knowledge in their center of diversity. For example in the district of Haquira, which is located in the province of Cotabambas, Apurimac, many young farmers abandon agriculture to work in the mines or migrate to search for more income attractive options in larger towns. The precise impact of these tendencies on agrobiodiversity has not been assessed and it remains difficult to establish timelines that reflect changes as no reference data exist that is useful for comparison. A cost efficient and easy applicable method to assess local crop diversity based on traditional names and establish a baseline for red-listing of landraces is the five cell analysis (FCA). In a case study, three communities in Haquira – Pauchi, Queuñapampa and Huancacalla Chico have been surveyed to determine the actual state of potato landrace, collective knowledge, potential threats of agrobiodiversity and to establish a long term monitoring system. It was registered by focus groups familiar (n=61). The results provide us information systematization of landraces of potatoes to prepare a master list that can be contrasted with genetic information. Based on farmer's perception in all the communities it was identified 42 landraces with 71 synonyms; 13 threatened landraces, 8 conservation dependant landraces and 3 no risk landraces. The methodologies used to contributing to data base for monitoring of landraces of potatoes should be applicable to other landscapes on similar conditions

Perturbations of Gauss-Bonnet Black Strings in Codimension-2 Braneworlds

We derive the Lichnerowicz equation in the presence of the Gauss-Bonnet term. Using the modified Lichnerowicz equation we study the metric perturbations of Gauss-Bonnet black strings in Codimension-2 Braneworlds.Comment: 26 pages, no figures, clarifying comments and one reference added, to be published in JHE

Tratamiento quirúrgico de los síndromes dolorosos regionales complejos tipo II y utilidad de la monitorización neurofisiológica intraoperatoria

ResumenEl propósito de esta revisión era presentar las bases bilógicas y fisiopatológicas de la formación de neuromas como causa de los síndromes dolorosos regional (SDRC) tipo II y el uso de la monitorización neurofisiológica intraoperatoria en el tratamiento de los SDRC tipo II secundarios a neuromas en continuidad y en nervios adheridos en cicatrices tras cirugías previas.AbstractThe purpose of this review article was to present the biological and physiological bases of the Complex Regional Pain Syndrome (CRPS) type II and the use of iIntraoperative neurophysiological monitoring in the treatment of CRPS type II secondary to neuroma-in-continuity and scar-tethered nerves

La regeneración del pinsapar en la sierra de Grazalema. I: análisis de la fase de plántula

Se estudia la dinámica de la regeneración del pinsapar en la Sierra de Grazalema. Previamente se ha llevado a cabo una diferenciación del conjunto del pinsapar a partir de la información disponible de inventarios, fotointerpretación, bibliografía y datos de campo, dando como resultados cuatro tipos estructurales: Pinsapar puro estructurado, Pinsapar puro latizal-fustal, Quejigal con pinsapos y Encinar con pinsapos. En este estudio, el análisis del proceso de regeneración se centra en el regenerado en estado de plántula, donde la mortalidad puede tener una incidencia enorme debida especialmente a la sequía estival propia del ámbito mediterráneo. Se ha establecido un dispositivo de muestreo sistemático en los cuatro estratos, medido una vez finalizada la germinación de semillas del año y después del verano. Con los datos obtenidos se ha estudiado tanto la incorporación, como la mortalidad de nuevas plántulas. Se han encontrado diferencias significativas entre los estratos de pinsapar puro y los mixtos, tanto en incorporación de nuevas plántulas como en mortalidad. También existen diferencias dentro de los dos estratos de pinsapar pur