Changes in floret development patterns that may correlate with sex determination in the PCK clade (Poaceae)
Reinheimer, Renata; Zuloaga, Fernando Omar; Vegetti, Abelardo Carlos; Pozner, Raúl Ernesto
We investigated changes in floral developmental patterns and sex determination in the PCK (phosphoenolpyruvate carboxykinase) clade using a comparative approach and SEM. We identified variation in patterns of floral development that may be correlated with sex determination. Nine different patterns of floret development were identified, based on sex of the lower floret, sequence of stamen development, and rate of glume and lemma differentiation. Although staminate florets are always formed by the abortion of the gynoecium, the timing of abortion differs among species. Similarly, the formation of sterile lower florets showed different pathways that may operate at the level of floral meristem or organ identity. Finally, we discuss several reasons why patterns described for maize and closely related species may not be easily extrapolated to other grasses.
Environmental impact analysis of methanol recovery in biodiesel production using the waste reduction algorithm WAR; Análisis del impacto ambiental de la recuperación de metanol en la producción de biodiesel usando el algoritmo de reducción de desechos WAR
Marticorena, Alfredo A.; Mandagaran, Beatriz Adriana; Campanella, Enrique Angel
The environmental impact of recovering methanol in the traditional process of biodiesel production is presented. Biodiesel represents an alternative for diminishing impact on the environment. However, there are several biodiesel production processes and all of them have different impact on the environment. The methodology consists of simulating the process, apply the WAR algorithm for waste reduction and compare the results. Comparison is also done with literature data for similar cases. The analysis shows that methanol recovery transforms the conventional process of biodiesel production into an environmental friendly process.
Selenium-based self-assembled monolayers: the nature of adsorbate-surface interactions
de la Llave, Ezequiel Pablo; Scherlis Perel, Damian Ariel
In recent years, self-assembled monolayers (SAMs) of selenols have been characterized using electrochemistry, scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), thermal desorption spectroscopy, and other experimental approaches. Interest in the relative stability and conductance of the Se - Au interface as compared to S-Au prompted different investigations which have led to contradictory results. From the theoretical side, on the other hand, the study of selenol-based SAMs has concentrated on the investigation of the electron transport across the Se-Au contact, whereas the structural and the thermodynamic features of the monolayer were essentially neglected. In this Article, we examine the binding of selenols to the Au(111) surface using density functional theory with plane wave basis sets and periodic boundary conditions. Our calculations provide insights on the geometry of the headgroup, the stability of the monolayer, and the electronic properties of the bond. In particular, we propose that the presence of a conjugated backbone might be a major factor determining the relative conductance at the monolayer, by differentially enhancing the intramolecular electron transport in selenols with respect to thiols. This surmise, if confirmed, would explain the conflictive data coming from the available experiments
Electrosynthesis of SER-active silver nanopillar electrode arrays
Feng, Jiu-Ju; Lu, Ya-Hui; Gernet, U.; Hildebrandt, Peter; Murgida, Daniel Horacio
Here we report a one step electrochemical method for the deposition of pillar-like silver nanostructures on graphite plate electrodes. The devices were tested as SER-active electrode arrays using covalently attached hemin. The nanopillar arrays provide reproducible surface enhanced resonance Raman (SERR) signals within 6% standard deviation and Raman enhancement factors of 1 × 105. They also show good electrochemical performance, as verified by potential-dependent SERR spectroscopy and cyclic voltammetry. Furthermore, the hemin-coated arrays display mediatorless electrocatalytic activity toward NO2-. Thus, the Ag nanopillar arrays present good prospects for their application in sensing devices and for SER/SERR based spectroelectrochemical applications in general.
La revista Católica Criterio y la defensa del hispanismo durante el segundo gobierno de Juan D. Perón (Argentina, 1952-1955); The Catholic journal Criterio and the defense of hispanism during the second government of Juan D. Peron (Argentina, 1952-1955)
Glozman, Mara Ruth
El segundo gobierno del presidente argentino Juan D. Perón (1952-1955) fue un período de fuertes confrontaciones entre sectores que impulsaban diferentes proyectos político-culturales. Uno de los aspectos polémicos del proyecto gubernamental fue la reivindicación del derecho del Estado nacional argentino para la producción de instrumentos lingüísticos propios, discurso que generó reacciones de rechazo de diferentes sectores sociales y políticos. En aquel contexto, la revista católica Criterio publicó una serie de notas y artículos de opinión en los cuales se expresaba una abierta defensa del legado hispánico y de la autoridad académica en materia idiomática. Este artículo se propone analizar el sistema de representaciones en el que se sustentaba la posición glotopolítica de la revista Criterio, articulando el estudio histórico de las ideologías lingüísticas con el análisis de las principales operaciones discursivo-argumentativas que se despliegan en los textos del corpus.
Detection and characterization of N-glycolyated gangliosides in Wilms tumor by immunohistochemistry
Scursoni, Alejandra M.; Galluzzo, Laura; Camarero, Sandra; Pozzo, Norma; Gabri, Mariano Rolando; De Acosta, Cristina Mateo; Vázquez, Ana María; Alonso, Daniel Fernando; De Davila, María Teresa G.
Gangliosides are glycolipids present on the cell surface. The N-glycolylated ganglioside NeuGc-GM3 has been described in some neoplasms, such as breast carcinoma and melanoma, but is usually not detected in normal human cells. Our aim was to evaluate the presence of NeuGc-GM3 in Wilms tumor by immunohistochemistry. Postchemotherapy tumors were grouped into different histologic subtypes considering the main preserved component. Formalin-fixed, paraffin-embedded tumor samples were cut into 5-mm sections. The monoclonal antibody 14F7, a mouse IgG1 that specifically recognizes NeuGc-GM3, and a peroxidase-labeled polymer conjugated to secondary antibodies were used. Sections from breast carcinoma were employed as positive controls. Presence of NeuGc-GM3 was evident in 22 of 25 (88%) cases. The staining was stronger in the epithelial component, with a membrane pattern and cytoplasmic diffusion. The stromal component expressed cytoplasmic NeuGc-GM3 in cells with rhabdomyoblastic differentiation. Tubules of adjacent renal tissue were also positive, but no expression of NeuGc-GM3 was detected in nontumoral fetal kidney. Until now, the expression of N-glycolylated gangliosides in pediatric solid tumors has not been investigated. The present study evidenced the expression of NeuGc-GM3 in a high proportion of Wilms tumors, suggesting its potential utility as a specific target of immunotherapy.
Diversity of trichomycetes in larval flies from aquatic habitats in Argentina
Siri, Augusto; Lopez Lastra, Claudia Cristina
Trichomycetes, mainly from nonbiting midge (Chironomidae), mosquito (Culicidae) and black fly (Simuliidae) larvae (Insecta: Diptera), are reported from diverse freshwater environments principally from previously unexplored areas of Argentina. Four new species of Harpellales are described: Austrosmittium patagonicum, A. lenticum, Smittium basiramosum and Legeriomyces lichtwardtii. This is the first report of Austrosmittium spp. from the Americas and the first report of a Legeriomyces from South America. Two other species (Simuliomyces sp. and Harpella sp.) are described but not named. Fourteen previously described species were recovered, and their geographical distribution and host ranges have been extended for Argentina, with Sm. phytotelmatum, Stachylina lentica, St. lotica and St. penetralis being new records for the country.
Needs Assessment for Climate Information on Decadal Timescales and Longer
Vera, Carolina Susana; Barange, M.; Dube, O. P.; Goddard, L.; Griggs, D.; Kobysheva, N.; Odada, E.; Parey, S.; Polovina, J.; Poveda, G.; Seguin, B.; Trenberth, K.
Societal needs for climate information on decadal timescales is confirmed in terms of its potential value and relevance as a driver in sector decision-making, but such information is currently lacking. Predictions and observationally based analyses for decadal climate variability and change are needed. In addition, the following issues have been identified as those that must be addressed in order to facilitate effective use of climate information on decadal timescales in the decision-making processes of different socio-economic sectors: building effective partnership systems linking stakeholders, users and decision-making sectors and climate information providers; more research and investment is to translate information of large-scale decadal variations into the regional and local scales required for decisions; maintaining and sustaining the Global Climate Observing System (GCOS), in particular, enhancement of the global ocean observing system; and, ways to assemble, check quality, reprocess and reanalyse datasets relevant to decadal prediction. Ways of securing climate observing systems particularly in least developed regions are urgently needed.
Holomorphic functions and polynomial ideals on Banach spaces
Carando, Daniel Germán; Dimant, Veronica Isabel; Muro, Luis Santiago Miguel
Given A a multiplicative sequence of polynomial ideals, we consider the associated algebra of holomorphic functions of bounded type, HbA(E). We prove that, under very natural conditions satisfied by many usual classes of polynomials, the spectrum MbA(E) of this algebra “behaves” like the classical case of Mb(E) (the spectrum of Hb(E), the algebra of bounded type holomorphic functions). More precisely, we prove that MbA(E) can be endowed with a structure of Riemann domain over E and that the extension of each f ∈ HbA(E) to the spectrum is an A-holomorphic function of bounded type in each connected component. We also prove a Banach-Stone type theorem for these algebras.
Comparison of marine and river water humic substances in a Patagonian environment (Argentina)
Scapini, Maria del Carmen; Conzonno, Victor Hugo; Balzaretti, Vilma Teresa; Fernandez Cirelli, Alicia
Structural aspects of humic substances (HSs) in marine waters of Engaño Bay (Atlantic Ocean) and water from the Chubut River (Patagonia, Argentina) were compared. The HSs were isolated, purified, and analyzed using a multiple-method approach for structural characterization: elemental analysis, nuclear magnetic resonance (13C and 1H NMR), infrared spectroscopy (FTIR), UV-visible absorption and fluorescence. Similarities between the marine and freshwater components were evaluated on the basis of N and O contents, H/C and C/N atomic ratios, infrared bands from nitrogen-containing and carboxylic groups, percentage of functional groups obtained from NMR spectra, spectral slope coefficient of absorption spectra, absorbance ratios at 250 and 365 nm (E2/E3), aromaticity, excitation–emission matrices and fluorescence quantum yield. Both the Engaño Bay and Chubut River waters have HSs that are mainly composed of fulvic acids (FAs); although they are very similar, they may be distinguished from one another. Similarities include the predominance of aliphatic carbon content (low aromatic content); however, the water bodies differed in their content of proteins and carboxylic acids. The Engaño Bay FAs have mainly an aquatic origin; although the Chubut River FAs suggest a similar aquagenic origin, there is also evidence of contributions from pedogenic FAs.
Perspectiva bioenergética de los residuos sólidos urbanos en el Valle de Lerma
Manrique, Silvina Magdalena; Franco, Ada Judith; Núñez, Virgilio; Seghezzo, Lucas
Los residuos sólidos urbanos (RSU), que tradicionalmente se han depositado a cielo abierto en el Valle de Lerma (Salta), podrían comenzar a ser dispuestos en un relleno sanitario regional en función de un proyecto provincial existente. El mencionado proyecto no incluye el aprovechamiento de la energía contenida en los RSU. En este trabajo se consideraron como recursos bioenergéticos potenciales. Dos clases de estimaciones fueron realizadas a partir de diferentes metodologías: a) poder calorífico de los RSU y potencial producción de electricidad y b) potencial biogás a obtenerse y potencial generación eléctrica. El aprovechamiento del potencial energético de estos residuos, sumado a los beneficios por mitigación de gases efecto invernadero, y demás aspectos ambientales, sin duda contribuirán a una mejor calidad de vida para la población del Valle.; The municipal solid waste (MSW), traditionally they have been deposited to opened sky in Lerma's Valley (Salta). Because a current provincial proyect, the MSW might begin to deposite in a sanitary regional landfill. The mentioned project does not include the MSW energy utilization. In this work they were considered to be energetic potential resources. Two classes of estimations were realized from different methodologies: a) heating power of the RSU and potential production of electricity and b) potential biogas to be obtaining and electrical generation. The utilization of the energetic potential of these residues, added to the benefits for gas mitigation greenhouse effect, and other environmental aspects, undoubtedly they will contribute to a better quality of life to the population of the Valley.
Bioenergía en el Valle de Lerma: evaluación de sustentabilidad de alternativas
Manrique, Silvina Magdalena; Franco, Ada Judith; Núñez, Virgilio; Seghezzo, Lucas
Estudios previos en el Valle de Lerma (Salta) han identificado diferentes sistemas bioenergéticos que podrían ser implementados en la zona. Estos sistemas son altamente complejos: incluyen diferentes etapas (desde su producción a su aplicación), sectores involucrados, disciplinas, recursos, entre otros. A su vez, estos sistemas están embebidos en un entramado social, territorial, y un contexto ambiental determinado. La complejidad resultante y el “nivel” de sustentabilidad de cada sistema deben ser estudiados, por tanto, desde una perspectiva integradora y de múltiples criterios. Los objetivos del presente estudio son: detectar, mediante la opinión de múltiples actores internacionales, los aspectos más importantes en la evaluación de la sustentabilidad de los sistemas bioenergéticos, y aplicar estos criterios en la realización de una Evaluación multi-criterio (EMC) de sistemas bioenergéticos del Valle. La metodología desarrollada se constituye en una herramienta práctica que permitirá una valoración global rápida y completa de sistemas bioenergéticos.; Previous studies in the Lerma Valley (Salta) have identified different bioenergy systems that might be implemented in the region. These systems are complex, since they include different stages, sectors, disciplines, and resources. These systems are also embedded in a specific social, territorial, and environmental context. The resulting complexity and the degree of sustainability of each system must be studied from an integral perspective using multiple criteria. The aims of this study are: i) to detect the most important aspects for the assessment of the sustainability of the bioenergy systems; ii) to apply these criteria in the multiple criteria assessment (MCA) of bioenergy systems of the Valley. Multiple international actors have been consulted through expert opinion polls. The methodology used can be a practical tool for a quick and complete assessment of a number of alternative bioenergy systems in the Lerma Valley and similar places in the region.
Pisces, Anegada Bay protected area, Buenos Aires province, Argentina
Llompart, Facundo Manuel; Molina, Juan Manuel; Lopez Cazorla, Andrea Cecilia; Baigun, Claudio Rafael M.; Colautti, Dario Cesar
We provide the first list of marine fish from Anegada Bay, a coastal protected area in Buenos Aires Province. Fish records were obtained from gillnets and recreational fishery captures. Thirty seven species belonging to 29 families and 18 orders were identified. The most numerous order was Perciformes with eight families and 10 species. Odontesthes argentinensis, Micropogonias furnieri, Cynoscion guatucupa and Mustelus schmitti were verified in all sampling sites and the last two were the most represented either in the experimental fishing and recreational captures. Presence of Lagocephalus laevigatus extended the so far known range distribution of this fish species, representing the southernmost records in Argentinean coastal waters. The fish fauna composition from Anegada Bay could be considered as from a transitional zone.
A dimensão econômica da teoria política aristotélica; Economical dimension of aristotle's political theory
Rossi, Miguel Ángel; Tierno, Patricio
O objetivo do artigo é enfatizar o lugar que ocupa a economia na cosmovisão política de Aristóteles, assumindo o pressuposto segundo o qual o filósofo considera a economia como uma dimensão central da mesma forma que uma condição de possibilidade para pensar a comunidade política. Nesse sentido, percorre-se três aspectos de tal problemática. O primeiro aspecto, o mais visível, cujo descobrimento é mérito da hermenêutica arendtiana, é aquele que diz respeito especificamente ao problema da crematística como desconstrução do objeto da política, considerada como vida comunitária ligada ao bom viver. O segundo aspecto é o que conduz o filósofo a vincular, pela primeira vez na história do Ocidente, os regimes políticos à estrutura social da polis. O terceiro aspecto consiste em realizar uma leitura dos regimes políticos na chave econômica, aspecto central das profundas críticas de Aristóteles à oligarquia. Desse modo, deixa-se explícita outra das hipóteses que se sustenta no texto: a de que as reflexões de Aristóteles se concentram na noção de esfera pública e, por isso, privilegiam teoricamente a aristocracia, a politeia e, inclusive, a democracia.; The objetive of the article is to emphasize the place of economics in the political cosmovision of Aristotle under the assumption of economics as a central dimension and a prerequisite of the philosopher's thinking about political community. In that sense, it covers three aspects of that problematic. The firs aspect, the most visible one, which discovery is merit of Arendtian hermeneutics, attends specifically to the problem of bad chrematistic as a deconstruction of the politics's object, in so far as communitarian life is related to the good life. The second aspect allows the philosopher to relate, for the first time in Western history, the political regimes to the social structure of the polis. The third aspect implies a vision of political regimes in economic terms and is the core of Aristotle's profound criticism of oligarchy. In that way, it makes explicit another assumptiom of this paper: that Aristotle's reflections are concentrated on the notion of public sphere and, for that reason, they privilege theoretically aristocracy, politeia, and even democracy.
Indicios arcaicos en la Colección Doncellas, Jujuy (República argentina): El «Yacimiento*» 26 a la luz de un fechado radiocarbónico (4811±39 AP); Vestiges archaïques de la Collection Doncellas, Jujuy (République argentine): «Le site» 26 à la lumière d´une datation au carbon 14 (4811±39 AP); Archaic remains in the Doncellas Collection, Jujuy (Argentina): «Site» 26 in light of carbon dating (4811±39 BP)
Perez, Cecilia Beatriz
En el presente trabajo se considera a la cestería, en sentido amplio, como una técnica textil que pone en relación dos o más elementos (trama y urdimbre) vegetales flexibles no hilados. Se analizan los materiales cesteros provenientes del enterratorio n.° 26 del sitio Doncellas, en la provincia de Jujuy, República argentina, adscrito a momentos tardíos de la ocupación prehispánica del noroeste argentino. Los resultados del estudio de la muestra completa de artefactos cesteros provenientes de todo el sitio indican una gran uniformidad técnico-morfológica en los mismos. La única excepción la constituye el enterratorio 26 en el que se dan artefactos cesteros de formas y técnicas que no aparecen en los demás conjuntos fúnebres. Un fechado radiocarbónico realizado sobre uno de ellos ubica este conjunto en el Período Arcaico Tardío, varios miles de años antes de lo esperado para la denominada cultura Doncellas, definida a partir de esta Colección.; La vannerie est considérée comme une technique textile dont les éléments végétaux flexibles, non soumis à une procédure de tissage, sont reliés entre eux et créent des surfaces planes. Cet article analyse la vannerie de la tombe 26 du site Doncellas, province de Jujuy (République Argentine). Ce site correspond à l´époque récente de l´occupation préhispanique du nord-ouest argentin. Les résultats de l´étude réalisée sur la vannerie provenant du site indiquent qu´il s´agit d´un ensemble tout à fait homogène en ce qui concerne les formes et les techniques appliquées. Mais la tombe 26 constitue une exception. À la lumière de la datation absolue on peut dire qu´il s´agit d´un ensemble qui correspond à la période Archaïque récente, plusieurs milliers d´années avant l´apparition de la culture Doncellas, définie à partir de cette Collection.; In this text, basketry is considered in its broadest sense as a textile technique that relates two unspun flexible vegetal elements (weft and warp). We analyse two basketry objects found in burial site no. 26 of the Doncellas site, in the province of Jujuy, Argentina. These were dated as late in the pre-hispanic occupation of north-east Argentina. The results of the analysis of all of the samples of wickerwork taken from the entire site indicate uniformity in forms and techniques. The only exception to this is burial site 26, in which are found basketry artifacts of forms and techniques not found in the other funeral ensembles. A carbon dating on one of these placed the assemblage in site 26 in the Late Archaic Period, many thousands of years before that expected for the «Doncellas Culture», defined on the basis on this collection.
A gynandromorph of Xylocopa nigrocincta Smith (Hymenoptera: Apidae); Un ginandromorfo de Xylocopa nigrocincta Smith (Hymenoptera: Apidae)
Lucia, Mariano; Abrahamovich, Alberto Horacio; Alvarez, Leopoldo Jesús
We describe a mixed gynandromorph of Xylocopa (Neoxylocopa) nigrocincta from a single specimen from Argentina. The specimen presents bilateral asymmetry, with the right half of its head displaying male characters and the left half displaying female characters; the mesosoma presents male characters mostly in the right half of the prothorax, pronotal lobe and distal half of the fore tibia and in the pubescence of tarsus; the rest of the mesosoma and the metasoma display female features.; Se describe un ginandromorfo mixto de Xylocopa (Neoxylocopa) nigrocincta de un ejemplar de Argentina. El ginandromorfo tiene asimetría bilateral en la cabeza, con su mitad derecha con caracteres del macho y su mitad izquierda con caracteres de la hembra. El mesosoma presenta algunas características de macho en la mitad anterior derecha (protorax, lóbulo pronotal, mitad posterior de la protibia y pubescencia del tarso), el resto de meso y metasoma con caracteres de la hembra.
La incorporación de los indios desnaturalizados del valle Calchaquí y de la región del Chaco a la jurisdicción de Córdoba del Tucumán: Una mirada desde la visita del oidor Antonio Martines Luxan de Vargas, 1692–1693
Gonzalez Navarro, Constanza Maria
This work is framed in the ethnohistorical perspective and attempts to show the alterations produced in the inter-ethnic relations due to the process of “denaturalization” and movements of the peoples from the valle Calchaquí and the Chaco region towards the jurisdiction of Córdoba city – part of the Viceroyalty of Peru – in the second half of the 17th century. This investigation takes as the main source the visita of Antonio Martines Luxan de Vargas (1692–1693), to which other judicial and capitulary sources have been included. The sources show the changes produced in the economy and local society due to the incorporation of foreign people into the jurisdiction. One of the most important changes we can see in this process is the alteration of the inter-ethnic relations prevailing since then, where the autochthonous population manifested submission to the system, showing few examples and signs of resistance to the local power. In this sense, the Calchaquí and Chaco population offered a more obvious resistance which, in exceptional cases – as it is the case of the “La Toma” natives – contributed to improve the social cohesion.
Los avances en la construcción del Estado Social en Córdoba (1914- 1930): Legislación social y prácticas asistenciales
Moreyra Villalba, Beatriz Ines
La historiografía argentina sobre la denominada cuestión social, ha multiplicado sus intereses temáticos en las dos últimas décadas. Dentro de la diversificación de problemáticas y de enfoques que la caracterizan, la producción dedicada al estudio de las condiciones materiales de vida de los sectores subalternos y la relación del Estado y la sociedad civil con la cuestión social, se constituyeron en colectivos historiográficos con identidad propia. En este contexto, el presente trabajo analiza la lenta transición hacia un protoestado social en la ciudad de Córdoba entre 1914 y 1930; es decir, el complejo y laxo proceso que va desde la solidaridad de la sociedad civil a la generalización de una solidaridad institucionalizada. Concordante con ello, se indaga el proceso histórico de estructuración de las medidas legislativas y asistenciales y las concepciones de lo social subyacentes a las decisiones normativas.; The Argentine historiography on the so-called social issue has multiplied its interests on the last two decades. Within the diversification of problems and approaches that characterize it, the production dedicated to the study of the actual conditions of life for the secondary sectors and the relationship that the State and the civil society bear to the social question have become historiographic groups with an identity of their own. In this context, the present paper analyzes the slow transition towards a social protostate in the city of Córdoba between 1914 and 1930; that is to say, the complex and lax process that moves from solidarity in civil society to the generalization of an institutionalized solidarity. Concurrent with that, it is investigated the historical process of structuring of legislative and welfare measures and the conceptions of the social underlying the decision concerning rules.
Identifying native-like protein structures with scoring functions based on all-atom ECEPP force fields, implicit solvent models and structure relaxation
Arnautova, Yelena A.; Vorobjev, Yury N.; Vila, Jorge Alberto; Scheraga, Haroldo A.
Availability of energy functions which can discriminate native-like from non-native protein conformations is crucial for theoretical protein structure prediction and refinement of low-resolution protein models. This article reports the results of benchmark tests for scoring functions based on two all-atom ECEPP force fields, that is, ECEPP/3 and ECEPP05, and two implicit solvent models for a large set of protein decoys. The following three scoring functions are considered: (i) ECEPP05 plus a solvent-accessible surface area model with the parameters optimized with a set of protein decoys (ECEPP05/SA); (ii) ECEPP/3 plus the solvent-accessible surface area model of Ooi et al. (Proc Natl Acad Sci USA 1987;84:3086–3090) (ECEPP3/OONS); and (iii) ECEPP05 plus an implicit solvent model based on a solution of the Poisson equation with an optimized Fast Adaptive Multigrid Boundary Element (FAMBEpH) method (ECEPP05/FAMBEpH). Short Monte Carlo-with-Minimization (MCM) simulations, following local energy minimization, are used as a scoring method with ECEPP05/SA and ECEPP3/OONS potentials, whereas energy calculation is used with ECEPP05/FAMBEpH. The performance of each scoring function is evaluated by examining its ability to distinguish between native-like and non-native protein structures. The results of the tests show that the new ECEPP05/SA scoring function represents a significant improvement over the earlier ECEPP3/OONS version of the force field. Thus, it is able to rank native-like structures with Cα root-mean-square-deviations below 3.5 Å as lowest-energy conformations for 76% and within the top 10 for 87% of the proteins tested, compared with 69 and 80%, respectively, for ECEPP3/OONS. The use of the FAMBEpH solvation model, which provides a more accurate description of the protein-solvent interactions, improves the discriminative ability of the scoring function to 89%. All failed tests in which the native-like structures cannot be discriminated as those with low energy, are due to omission of protein–protein interactions. The results of this study represent a benchmark in force-field development, and may be useful for evaluation of the performance of different force fields. Proteins 2009.
