Are Orchid Bees (Apidae: Euglossini) Good Indicators of the State of Conservation of Neotropical Forests?

This work discusses the criteria proposed to consider wild bees as bioindicators and specifically applied to orchid bees in neotropical forests. Some of the issues are: 1) the deficiencies of the sampling methods, which makes it difficult to accurately assess species inventories. 2) missing knowledge about the biology of many species. 3) spatial or temporal distribution of most species remains unknown, which may misslead the results of short-term studies. 4) It is not clear whether orchid bees are affected by climate change as seen in other bees, which weakens their predictive potential. 5) A measure of the economic benefits provided by orchid bees is needed to better appraise them and their conservation. Finally, future studies should develop predictive models for conservation, accounting for evolutionary aspects like phylogeny or distributions; together with studies of the effect of disturbance on the physiology of the bees

Biomedical Journals and Global Poverty: Is HINARI a Step Backwards?

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Evolución de la energía de fractura de dos hormigones resistentes a la acción de ciclos hielo-deshielo

The current standards that regulate use of structural concrete have highlighted the durability of concrete. However, how the fracture energy of concrete evolves under the action of freeze-thaw cycles is not well known. The fracture energy of two types of concrete, one with an air-entraining additive and the other with silica fume addition, is studied after four, 14 and 28 freeze-thaw cycles. The results obtained show that the concrete with an air-entraining additive was undamaged and that fracture energy grew slightly. In addition to this, they also showed that the concrete with silica fume addition suffered severe surface scaling and its fracture energy changed due to the greater fracture areas generated.La actual normativa que rige el empleo de hormigón estructural ha puesto enfásis en la durabilidad del hormigón. Sin embargo, no se conoce cómo evoluciona la energía de fractura del hormigón sometido a ciclos hielo- deshielo, lo cual es de vital importancia para asegurar la durabilidad y el correcto comportamiento mecánico de las estructuras de hormigón en entornos con heladas durante su vida útil. Se ha estudiado la evolución de la energía de fractura de un hormigón con aireante y de un hormigón con humo de sílice después de 4, 14 y 28 ciclos hielo-deshielo realizando ensayos de fractura. Los resultados muestran cómo el hormigón con aireante no sufre daño por los ciclos hielo-deshielo y cómo la energía de fractura del mismo aumenta ligeramente. El hormigón con humo de sílice se daña por los ciclos hielo-deshielo y reduce su energía de fractura al aumentar el area fracturada

Spalling uniaxial strength of Al2O3 at high strain rates

In this article research into the uniaxial tensile strength of Al2O3 monolithic ceramic is presented. The experimental procedure of the spalling of long bars is investigated from different approaches. This method is used to obtain the tensile strength at high strain rates under uniaxial conditions. Different methodologies proposed by several authors are used to obtain the tensile strength. The hypotheses needed for the experimental set-up are also checked, and the requirements of the set-up and the variables are also studied by means of numerical simulations. The research shows that the shape of the projectile is crucial to achieve successfully tests results. An experimental campaign has been carried out including high speed video and a digital image correlation system to obtain the tensile strength of alumina. Finally, a comparison of the test results provided by three different methods proposed by different authors is presented. The tensile strength obtained from the three such methods on the same specimens provides contrasting results. Mean values vary from one method to another but the trends are similar for two of the methods. The third method gives less scatter, though the mean values obtained are lower and do not follow the same trend as the other methods for the different specimens

PERMEABILIDAD DENTINARIA

Se entiende por permeabilidad dentinaria a la capacidad de difusión y/o transporte de fluidos y solutos a través del sistema canalicular comunicante.Se entiende por permeabilidad dentinaria a la capacidad de difusión y/o transporte de fluidos y solutos a través del sistema canalicular comunicante

Biología del fibrocartílago articular frente a las demandas funcionales

The functional demand of the temporomandibular joint requires an appropriate biological answer of the tissue that recaver the articular surfaces and the disk, which are interdependent in the functional and structural together with the synovial liquid The fibrocartilage has great copacity of rellular answer in front of the functional requirements, under conditions of normal load it is able to support and to dissipate the forces, however, in eventual loads that overcome the tisular tolerance it will break the homeostatic balance and the illness will begin. the nutritional deficiencies are the related factor with the dysfunctions articulate for deficiency or absence of the synovial liquid, altering the lubrication process The mechanical injury, also that it can limit the cellular functions and to alter the step of the nutrients by way of the synovial fluid, it produces liberation of free radicals that can be implied in the degradation of the Hialuronic Acid and the Prostaglandins production. The liberation catepsíns B and D for rupture of superficial chondrocytes, reviled lo the cartilage generating persistent inflammatory reactions. Other enzymes that participate in the degradation of cartilaginous matrix, bones, ligaments and tendons, are the metalloproteinase's, elaborated by chondrocytes by inductión of lnterleucin-1 o'clock, synthetized by macrophages during the ínflammation. the Alpha Necrosis Tumoral Factor (FNT), secreted by monocytes and macrophages, not only it acts as mediator of the inflammation, stimulating to synovials cells to the production of Prostaglandin, but it also induces to fibroblasts to synthetize Collagenaze that acts as mediator of the bony resorption.La demanda funcional de la Articulación Temporomandibular requiere de una adecuada respuesta biológica de los tejidos que recubren las superficies articulares y el disco, los cuales son interdependientes en lo funcional y estructural juntamente con el líquido sinovial Los fibrocartílagos tienen gran capacidad de respuesta celular frente a los requerimientos funcionales, en condiciones de carga normal es capaz de soportar y disipar las fuerzas, sin embargo, en eventuales cargas que superan la tolerancia tisular se romperá el equilibrio homeostático y se iniciará la enfermedad. Las deficiencias nutricionales es el factor vinculante con los trastornos articulares por deficiencia o ausencia del líquido sinovial, alterando el proceso de lubricación.La injuria mecánica, además que puede limitar las funciones celulares y alterar el paso de los nutrientes por vía del fluido sinovial, produce liberación de radicales libres que pueden estar implicados en la degradación del Acido Hialurónico y la producción de Prostaglandinas. La liberación de calepsinas B y D por ruptura de condrocitos superficiales, injuriaran al cartílago generando reacciones inflamatorias persistentes. Otras enzimas que participan en la degradación de matriz extracelular de cartílagos, huesos, ligamentos y tendones, son las metaloproteinasas, elaboradas por condrocitos por inducción de la Interleucina-1, sintetizada por macrófagos duranle la inflamación. El Factor de Necrosis Tumoral Alfa (FNT ), secretado por monocitos y macrófagos, no solo actúa como mediador de la inflamación, estimulando a células sinoviales a la producción de Prostaglandina, sino también induce a fibroblastos a sintetizar Colagenaza, que actúa como mediador de la resorción ósea

Memetic electromagnetism algorithm for surface reconstruction with rational bivariate Bernstein basis functions

Surface reconstruction is a very important issue with outstanding applications in fields such as medical imaging (computer tomography, magnetic resonance), biomedical engineering (customized prosthesis and medical implants), computer-aided design and manufacturing (reverse engineering for the automotive, aerospace and shipbuilding industries), rapid prototyping (scale models of physical parts from CAD data), computer animation and film industry (motion capture, character modeling), archaeology (digital representation and storage of archaeological sites and assets), virtual/augmented reality, and many others. In this paper we address the surface reconstruction problem by using rational Bézier surfaces. This problem is by far more complex than the case for curves we solved in a previous paper. In addition, we deal with data points subjected to measurement noise and irregular sampling, replicating the usual conditions of real-world applications. Our method is based on a memetic approach combining a powerful metaheuristic method for global optimization (the electromagnetism algorithm) with a local search method. This method is applied to a benchmark of five illustrative examples exhibiting challenging features. Our experimental results show that the method performs very well, and it can recover the underlying shape of surfaces with very good accuracy.This research is kindly supported by the Computer Science National Program of the Spanish Ministry of Economy and Competitiveness, Project #TIN2012-30768, Toho University, and the University of Cantabria. The authors are particularly grateful to the Department of Information Science of Toho University for all the facilities given to carry out this work. We also thank the Editor and the two anonymous reviewers who helped us to improve our paper with several constructive comments and suggestions

Encuentro de editores científicos

La Asociación Peruana de Editores Científicos (APECi), entidad dedicada a fomentar la publicación de artículos y revistas científicas con estándares internacionales, estuvo presente en nuestra casa superior de estudios a fines de noviembre del 2006 con motivo del Primer Encuentro Nacional de Editores de Revistas Científicas (ENERC 1) realizada con la finalidad de alcanzar los objetivos que persigue.La Asociación Peruana de Editores Científicos (APECi), entidad dedicada a fomentar la publicación de artículos y revistas científicas con estándares internacionales, estuvo presente en nuestra casa superior de estudios a fines de noviembre del 2006 con motivo del Primer Encuentro Nacional de Editores de Revistas Científicas (ENERC 1) realizada con la finalidad de alcanzar los objetivos que persigue

Identifying Ultra-Cool Dwarfs at Low Galactic Latitudes: A Southern Candidate Catalogue

We present an Ultra-Cool Dwarf (UCD) catalogue compiled from low southern Galactic latitudes and mid-plane, from a cross-correlation of the 2MASS and SuperCOSMOS surveys. The catalogue contains 246 members identified from 5042 sq. deg. within 220 deg. <= l <= 360 deg. and 0 deg. < l <= 30 deg., for |b| <= 15 deg. Sixteen candidates are spectroscopically confirmed in the near-IR as UCDs with spectral types from M7.5V to L9. Our catalogue selection method is presented enabling UCDs from ~M8V to the L-T transition to be selected down to a 2MASS limiting magnitude of Ks ~= 14.5 mag. This method does not require candidates to have optical detections for catalogue inclusion. An optimal set of optical/near-IR and reduced proper-motion selection criteria have been defined that includes: an Rf and Ivn photometric surface gravity test, a dual Rf-band variability check, and an additional photometric classification scheme to selectively limit contaminants. We identify four candidates as possible companions to nearby Hipparcos stars -- observations are needed to identify these as potential benchmark UCD companions. We also identify twelve UCDs within a possible distance 20 pc, three are previously unknown of which two are estimated within 10 pc, complimenting the nearby volume-limited census of UCDs. An analysis of the catalogue spatial completeness provides estimates for distance completeness over three UCD MJ ranges, while Monte-Carlo simulations provide an estimate of catalogue areal completeness at the 75 per cent level. We estimate a UCD space density of Rho (total) = (6.41+-3.01)x10^3/pc^3 over the range of 10.5 <= MJ ~< 14.9, similar to values measured at higher Galactic latitudes (|b| ~> 10 deg.) in the field population and obtained from more robust spectroscopically confirmed UCD samples.Comment: MNRAS accepted April 2012. Contains 30 figures and 11 tables. Tables 2 and 6 to be published in full and on-line only. The on-line tables can also be obtained by contacting the author

Parameterized optimized effective potential for atoms

The optimized effective potential equations for atoms have been solved by parameterizing the potential. The expansion is tailored to fulfill the known asymptotic behavior of the effective potential at both short and long distances. Both single configuration and multi configuration trial wave functions are implemented. Applications to several atomic systems are presented improving previous works. The results here obtained are very close to those calculated in either the Hartree-Fock and the multi configurational Hartree-Fock framework.Comment: 8 pages, 3 figure