Resumen En 1874, Florentino Ameghino (1853-1911) recolectó un extraño loricárido en las aguas del Río Luján, fundando una nueva especie. Lo denomina Typupiscis Lujanensis, hace tomar cuatro fotografías y lo presenta el mismo año al director del Museo Público Germán Burmeister, quien desestima el hallazgo al clasificarlo, erróneamente, como Hypostomus plecostomus. El análisis de tres de estas albúminas, junto a los testimonios sobre la morfología y etología de un ejemplar en cautiverio, permite determinar que los especímenes extraídos del Río Luján en 1874 y en 1884, pertenecen a Ancistrus cirrhosus, especie que ya había sido recolectada en el Plata por d’Orbigny en 1827 y descripta por Valenciennes en 1847. Las albúminas de Ancistrus por Annaratone, junto a las de restos de Panochtus encargadas por Burmeister hacia 1874 colocan a ambos entre los pioneros de la utilización de la fotografía en objetos de historia natural en Argentina.

Abstract In 1874, Florentino Ameghino (1853-1911) collected a strange catfish in the Luján river, founding a new species. He named it Typupiscis Lujanensis, took four photographs and presented it to the director of the Public Museum, Germán Burmeister, who dismisses the finding by erroneously classifying it as Hypostomus plecostomus. The analysis of three of these albumen photographs, together with penecontemporaneous testimonies on the morphology and the ethology of a specimen in captivity, allow to determine that the specimens fished in the Luján river in 1874 and in 1884, belong to Ancistrus cirrhosus, a species that was already collected in the Río de la Plata by d’Orbigny in 1827 and described by Valenciennes in 1847. The Annaratone’s albumen of Ancistrus, together with those of Panochtus commissioned by Burmeister in 1874 place them among the pioneers of the use of photography in natural sciences in Argentina.

Abstract: This article investigates the effects of public financing policies on the expansion of social mobility and coverage, between the years 1990 to 2015, in the Chilean higher education. It is based on the combination of three different methods: the case study; documentary research supported by primary and secondary sources, and the compilation and analysis of statistical information. It also analyses the need to revalue investment in the production of knowledge based on in academic research as part of the social role of universities. Finally, it shows that the current system of financing has influenced, directly and positively in the social mobility of the country, especially in the first two income quintiles. It also explains the importance of educational and research work of universities in favour of development and social progress.

Resumen: El presente artículo investiga los efectos de las políticas de financiamiento público en la expansión de la cobertura y la movilidad social, entre los años 1990 y 2015, en la educación superior chilena. Se sustenta en la combinación de tres métodos diferentes: el estudio de caso, la investigación documental apoyada en fuentes primarias y secundarias, y la recopilación y análisis comparativo de información estadística. Analiza, además, la necesidad de revalorizar la inversión en la producción de conocimiento basado en la investigación académica como parte del rol social de las universidades. Finalmente, demuestra que el sistema actual de financiamiento ha influido, directa y positivamente en la movilidad social del país, especialmente en los dos primeros quintiles de ingreso. Asimismo, explicita la importancia de la labor formativa y de investigación de las universidades en favor del desarrollo y el progreso social.

The improvement in the supply of accounting information undoubtedly leads to greater efficiency in organizations, allowing them to more easily achieve their objectives. The objective of this article is to analyze the current accounting record system of Spanish associations dedicated to the promotion of health in the elderly. For this, all the relevant standards related to the accounting management of such associations have been analyzed, and the provisions of the current 2007 General Accounting Plan have been compared with those of the old 1990 Plan, to check whether the sectoral adaptation of 1998 is obsolete or if there are some discrepancies between the two provisions mentioned above. Obviously, the applicable international accounting regulations (NIC/IFRS) have also been studied. The study makes it possible to verify that the current General Accounting Plan for 2007 involves changes of great relevance with respect to the accounting information of associations for the promotion of health in old age, for which the old sectoral adaptation of 1998 is obsolete and should be updated.

La mejora en el suministro de información contable conlleva, sin duda, una mayor eficiencia en las organizaciones, permitiéndoles alcanzar más fácilmente sus objetivos. El objetivo de este artículo es analizar el sistema actual de registro contable de las asociaciones españolas dedicadas al fomento de la salud en adultos mayores. Para esto se han analizado todas las normas de relevancia relacionadas con la gestión contable de tales asociaciones, y se han comparado las disposiciones del actual Plan General de Contabilidad de 2007 con las del antiguo de 1990, para comprobar si la adaptación sectorial de 1998 ha quedado obsoleta o si existen algunas discrepancias entre las dos disposiciones mencionadas anteriormente. También, obviamente, se ha estudiado la normativa contable internacional aplicable (NIC/NIIF). El estudio permite comprobar que el actual Plan General de Contabilidad de 2007 supone cambios de gran relevancia respecto a la información contable de las asociaciones de fomento de la salud en adultos mayores, por lo cual la antigua adaptación sectorial de 1998 queda obsoleta y debería ser actualizada.

Abstract The objective of this study is to model a retention predictive system for first-year students at Universidad Bernardo O’Higgins (Santiago de Chile), by determining which of the variables of entry into higher education, whether these are academic, social or relatives, are revealed significant for this analysis. The construction of the research model was based on a thorough bibliographic review which made possible to identify explanatory variables of university dropout in the national context. Afterwards, from the systematization of socio-educational backgrounds of the students from the 2014 and 2015 cohorts available in the university’s computer systems, a tripartite matrix was consolidated with the data associated with the variables that emerged from the analysis of the target group consulted. Consequently, we analyzed the relationship of each of the explanatory variables of the study with the variable control student desertion. The bivariate analysis allowed us to identify seventeen variables, significantly associated with student desertion and to specify dependency relations with the abandonment of studies. The multivariate model predicted abandonment behavior in 86.4%, indicating seven independent categorical variables that, finally, are revealed as relevant factors of the prediction model. The varied and sustained interpretations delivered in the results of the model, as well as the proposed suggestions to improve the university retention index, provide a direct value to the study aimed at optimizing one of the most important indicators linked to the quality management in universities, as is the student retention.

Resumen El presente estudio tiene como objetivo modelar un sistema predictivo de retención de los estudiantes de primer año de la Universidad Bernardo O´Higgins - UBO (Santiago de Chile), determinando cuáles de las variables de entrada a la educación superior, ya sean estas académicas, sociales o familiares, se revelan significativas para este análisis. La construcción del modelo de investigación se sustentó en una exhaustiva revisión bibliográfica que permitió identificar variables explicativas de la deserción universitaria en el contexto nacional. Luego, a partir de la sistematización de antecedentes socioeducativos de los estudiantes de las cohortes 2014 y 2015 disponibles en los sistemas informáticos de la universidad, se consolidó una matriz tripartita con los datos asociados a las variables que emergieron del análisis de los referentes consultados. Consecuentemente, se analizó la relación de cada una de las variables explicativas del estudio con la variable control deserción estudiantil. El análisis bivariado permitió identificar diecisiete variables, significativamente asociadas con la deserción estudiantil y precisar las relaciones de dependencia con el abandono de estudios. El modelo multivariado predijo en un 86,4 % la conducta de abandono señalando siete variables categóricas independientes que, finalmente, se develan como factores relevantes del modelo predicción. Las variadas y sustentadas interpretaciones entregadas en los resultados del modelo, así como las sugerencias propuestas para mejorar el índice de retención universitaria, entregan un valor directo al estudio dirigido a optimizar uno de los indicadores más importantes vinculados a una gestión de calidad en las universidades, como es, la retención estudiantil.

In 1881 Ameghino described the fossil human remains of Arroyo Frías as its more relevant finding, considering it to be the oldest of Pampean sites since the remains were unearthed from his Pliocene Upper Pampean. He realized this finding by the end of 1872, announces it to Burmeister in January of 1874 and, in September he continued the excavation with professor Ramorino. In spite of that, he will not obtain any official recognition since, in 1876, the commissioners of the Sociedad Científica Argentina explored the area of the Cañada de Rocha creek, believing they were in the Frías valley. Victims of this confusion Moreno, Zeballos and Lista declared that Ameghino mistakenly attributed an older “diluvian” age to very recent geologic layers, strongly eroding his reputation and scientific credibility. It is analyzed here the historical context of this disagreement that stigmatized for decades the archeological prospection of Pampean plains, while we present a geologic model with new 14C and OSL dates, in order to understand why Ameghino erroneously attributed a great antiquity to these layers. Also arise other geoarchaeological issues when these new data are confronted with the detailed descriptions of this author.

En 1881 Ameghino describió los restos humanos del arroyo Frías como su descubrimiento más importante ya que lo consideraba el más antiguo al atribuirlo a su Pampeano Superior de edad pliocena. Realizó este hallazgo a fines de 1872, lo presenta a Burmeister en enero de 1874 y, en septiembre del mismo año excava junto al Profesor Ramorino. A pesar de ello, no obtendrá ningún reconocimiento oficial ya que, en 1876 los comisionados de la Sociedad Científica Argentina inspeccionan la Cañada de Rocha, confundiéndola con el arroyo Frías. Víctimas de esta confusión Moreno, Zeballos y Lista afirmarán erróneamente que Ameghino consideró “diluvianas” a capas geológicas muy recientes, privándolo de credibilidad frente a los círculos científicos porteños. Se analiza el contexto histórico de este desencuentro que estigmatizó por décadas la prospección de la llanura pampeana y se presenta un modelo geológico, más dataciones 14C y OSL, que permiten comprender por qué Ameghino le atribuyó a estos restos gran antigüedad. Además, esos nuevos datos plantean otros interrogantes geoarqueológicos al confrontarlos con las detalladas descripciones de este autor.

RESUMO: Particionamento de tarefas em animais eusociais é provavelmente uma adaptação evolutiva, que otimiza a eficiência de forrageio da colônia, gerando maior capacidade de crescimento e reprodução. Nós investigamos o particionamento indireto de tarefas, com o envolvimento de castas de dois tamanhos distintos. Assim, o material coletado por uma formiga não era transportado diretamente ao ninho, nem transferido diretamente de um indivíduo para outro, mas sim descartado por uma formiga e coletado por outra. Em duas abordagens distintas, nós confirmamos em Atta sexdens rubropilosa resultados anteriores relativos à ocorrência deste particionamento indireto de tarefas, observado em Atta colombica . Mostramos também que, assim como em Atta colombica , há uma correlação entre os tamanhos da formiga e do fragmento de folha transportado quando esta corta e transporta este fragmento ao ninho (CaT). Mais ainda, confirmamos em Atta sexdens que, quando o particionamento de tarefas ocorre e as formigas apenas transportam o fragmento de folhas (T) cortadas por outras formigas, a correlação desaparece. Nós também descrevemos que as formigas CaT são menores do que as T.

ABSTRACT: Task partitioning in eusocial animals is most likely an evolutionary adaptation that optimizes the efficiency of the colony to grow and reproduce. It was investigated indirect task partitioning in two castes sizes; this involves task partitioning in which the material transported is not transferred directly from one individual to another, but where it is dropped by one ant to be picked up by another. In two separate approaches, it was confirmed previous results pertaining to leaf caching activities among Atta colombica with task partitioning activities involving leaf dropping among Atta sexdens rubropilosa , in which there is a correlation between the size of an individual ant and the leaf fragment it transports. It was also suggested that this correlation exists only in individual ants that cut and transport (CaT) the same fragment to the nest. When task partitioning occurs and individual ants transporting (T) leaf fragments cut by other ants, the correlation becomes looser or disappears. We also observed that CaT ants are smaller than T ants.

Between 1870 and 1884, Florentino Ameghino consecrated all his efforts to document and to prove the coexistence of man and Pampean megafauna in the Luján valley. He described several sites in channel and alluvial plain settings in valleys incised on Pampean loess. The geoarchaeological context of these sites, characterized by the abundance of megafauna modified bones, were never studied again after the publication of La Antigüedad del Hombre en el Plata in 1880-81. Here we present a stra-tigraphical reevaluation and reinterpretation of his "Piso Lujanense" based on a sequence stratigraphy analysis and AMS, OSL and ESR dating. We conclude that the Pleistocene valley fill spans from OIS 4 to OIS 2 with sequence boundaries at 75, 55, 30, 17 and 13 ky BP, reflecting the OIS 4 to OIS 2 glacioeustatic falls in the pampas valleys. These deposits were sealed by a rich organic matter layer or black mats, indicating an abrupt climatic change with a dramatic increase of humidity starting sometime between 12.5 and 13 ky BP. The associated ecological changes probably triggered the extinction process.

Entre 1870 y 1884, Florentino Ameghino consagró todos sus esfuerzos en documentar y probar la coexistencia del hombre y la megafauna pampeana en el Valle de Luján. Definió así una decena de sitios en contexto de canal y planicie aluvial en los valles incisos en el loess pampeano. El contexto geoarqueológico de dichos sitios, caracterizados por numerosos restos óseos de megafauna supuestamente modificados, nunca fue integralmente analizado luego de su publicación en La Antigüedad del Hombre en el Plata en 1880-81. Aquí se presentan nuevas evaluaciones e interpretaciones de su "Piso Lujanense" (Ameghino 1884,1889) en base a un análisis secuencial y dataciones AMS, OSL y ESR. Se concluye que los depósitos de relleno de valle pleistocenos comprenden cuatro secuencias fluvio-palustres con límites en 75, 55, 30,17 y 13 ka AP, reflejo en la pampa de los respectivos descensos glacieustáticos correspondientes a los estadios isotópicos OIS 4 al OIS 2. Estos depósitos se encuentran generalmente sellados por un horizonte oscuro, rico en materia orgánica, denominados mantos negros {black mats), que indican un cambio climático abrupto con un importante aumento de condiciones húmedas entre 12,5 y 13 ka AP. Los cambios ecológicos asociados habrían iniciado el proceso de extinción de la megafauna.

Neste trabalho é proposta uma metodologia analítica para extrair 1-nitronaftaleno, 2-nitrofluoreno, 9-nitroantraceno, 3-nitrofluoranteno e 1-nitropireno como compostos modelos para nitropoliaromáticos (nitro-HPA) em amostras aquáticas. A cromatografia líquida capilar com detecção UV on-column (µLC-UV) foi empregada para separar e quantificar todos os cinco nitro-HPA extraídos. Duas técnicas diferentes de extração foram testadas e comparadas: extração líquido-líquido (LLE) e extração em fase sólida (SPE) com dois diferentes tipos de sorbentes: partículas octadecilssilica (C18) e estireno divinilbenzeno (XAD-2). A eluição dos analitos foi testada com diclorometano e acetonitrila. O melhor resultado de recuperação foi obtido para extração SPE C18 com diclorometano com valores variando de 76 a 97% e valores de desvio padrão relativo menores que 4%. As condições cromatográficas para análise foram desenvolvidas empregando uma coluna capilar (250 × 0,3 mm) empacotada com partículas C18 de 5 µm com eluição isocrática de 65% de acetonitrila em água (v/v) com vazão de 7 µL min-1. Os limites de detecção obtidos no sistema UV on-column (abrangendo de ~3 a 30 µmol L-1) são limitantes para uma aplicação ambiental, porém adequados a estudos de toxicidade.

In this work, an analytical methodology to extract 1-nitronaphthalene, 2-nitrofluorene, 9-nitroanthracene, 3-nitrofluoranthene, and 1-nitropyrene aquatic samples is proposed. Capillary liquid chromatography with on-column UV detection (µLC-UV) was employed to separate and quantitate all five nitrated polycyclic aromatic hydrocarbons (nitro-PAH) extracted from water samples. Two different extraction techniques were tested and compared: liquid-liquid extraction (LLE) and solid phase extraction (SPE) with two different sorbents, octadecylsilica (C18) and styrene divinylbenzene (XAD-2) particles. The elution of analytes was tested with both acetonitrile and methylene chloride. The best recovery results were obtained for SPE-C18 extraction with the methylene chloride with values ranging from 76 to 97% with RSD values smaller than 4%. The chromatographic conditions for analysis was carried out using a 250 × 0.3 mm i.d. packed capillary column with 5 µm C18 particles. The elution was isocratic with 65% acetonitrile in water (v/v) as mobile phase with a flow rate of 7 µL min-1. The detection limits due to on-column UV detection (ranging ~3-30 mmol L-1) are limiting for environmental applications, however, they are suited for toxicological studies.