Abstract The ASTM A-36 steel is the main material used in the manufacture of products and parts for general construction and mechanical engineering purposes. In this work, the effect of boron-carbon coating on corrosion resistance and hardness of the steel ASTM A-36 is reported. A boriding thermochemical treatment was performed at 950o C during 4 h. Followed by, a carburizing process for 6 h at 930o C. The corrosion analysis was done by electrochemical impedance spectroscopy (EIS) polarization and Tafel technique, which employed a fused deposition modeling-based 3D printing electrochemical cell made of polylactic acid (PLA). A commercial platinum foil and a silver/silver chloride (Ag/AgCl) electrode with 3.5 M potassium chloride electrode solution (Electrolyte) were employed as the counter and reference electrode, respectively. and area 1 cm2 of the sample was employed as the working electrode (WE). Optical microscopic analysis shows that boride phase grown on the treated surfaces has a shark-tooth morphology with a thickness of about 60 µm in samples. The carburizing over boride layer promotes the conformation of coatings on the outermost layer of the samples with a thickness of about 17 µm. X-ray diffraction (XRD) spectrum shown only the formation of the iron diboride phase (Fe2B). Results shows that boride samples have inferior corrosion resistance in comparison to virgin sample, but after carburizing, an outer layer is formed, with the hardness and corrosion resistance similar to the original sample.

Abstract The Yabotí Biosphere Reserve (Prov. Misiones, Argentina) with 221,155 ha, represents one of the southernmost relicts of the Paranaense forest. Currently, a project is being developed in the area to inventory and describe the ferns and lycophytes. As a result of these studies, we identify a new species of Amauropelta, A. yabotiensis. Within this genus, it belongs to the group of species with uncinate hairs and presents a unique combination of diagnostic features, including the type of pubescence on the rhizome scales, the shape of the fronds and segments and type of venation. Here, we described and illustrated the species and we analyzed its taxonomic affinities and geographic distribution. Additionally, we provided a distribution map and a key to distinguish it from other Amauropelta species from Misiones province. With this new finding, we highlighted the importance of the Yabotí Reserve as a reservoir of biodiversity in the region.

Abstract Introduction: This article summarizes the clinical practice guideline (CPG) for the initial pharmacological treatment of lupus nephritis in the Social Security of Peru (EsSalud). Objective: To provide evidence-based clinical recommendations for initial pharmacological treatment of non-refractory adults with class I to V lupus nephritis in EsSalud. Methods: A guideline development group (GDG) was formed, which included specialist physicians and methodologists, who formulated clinical questions. Systematic searches were conducted for systematic reviews and - when deemed relevant - primary studies in PubMed during 2021. Evidence was selected to answer each of the clinical questions posed. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. In periodic working meetings, the GEG used the GRADE methodology to review the evidence and formulate recommendations. The CPG was reviewed by external experts before its approval. Results: The CPG addressed 6 clinical questions, divided into 2 topics: initial treatment of the induction and maintenance phase. Based on these questions, 11 recommendations were formulated (all conditional), 22 points of good clinical practice, and 2 flow charts. Conclusion: Evidence-based recommendations were issued for the management of patients with this pathology.

Resumen Introducción: El presente artículo resume la guía de práctica clínica (GPC) para el tratamiento farmacológico inicial nefritis lúpica en el Seguro Social del Perú (EsSalud). Objetivo: Proveer recomendaciones clínicas basadas en evidencia para tratamiento farmacológico inicial de adultos con nefritis lúpica clase I a V no refractarios en EsSalud. Métodos: Se conformó un grupo elaborador de la guía (GEG) que incluyó médicos especialistas y metodólogos, el cual formuló preguntas clínicas. Se realizaron búsquedas sistemáticas de revisiones sistemáticas y -cuando fue considerado pertinente- estudios primarios en PubMed durante el 2021. Se seleccionó la evidencia para responder cada una de las preguntas clínicas planteadas. Se evaluó la certeza de evidencia usando la metodología Grading of Recommendations Assessment, Development, and Evaluation (GRADE). En reuniones de trabajo periódicas, el GEG usó la metodología GRADE para revisar la evidencia y formular las recomendaciones. La GPC fue revisada por expertos externos antes de su aprobación. Resultados: La GPC abordó 6 preguntas clínicas, divididas en 2 temas: tratamiento inicial de la fase de inducción y mantenimiento. En base a dichas preguntas se formularon 11 recomendaciones (todas condicionales), 22 puntos de buena práctica clínica, y 2 flujogramas. Conclusión: Se emitieron recomendaciones basadas en evidencia para el manejo de pacientes con esta patología.

Abstract Background: In the Spanish language, there exists a considerable heterogeneity regarding the translation and use of the term “stroke,” which has multiple implications for epidemiology and science as well as the general population. Objective: The objective of the present study was to complete a Delphi exercise on the terminology for the Spanish equivalent for the term “stroke” in a group of Mexican experts in vascular neurology. Methods: A 3-phase consensus process was carried out using the Delphi method. The convened experts who agreed to participate completed an initial questionnaire. Subsequent questionnaires were designed based on the initial results. The final consensus was validated in a different group of researchers. Results: 69 stroke specialists participated in the first round, 78% also participated in the second round, and 72% in all three rounds. From an initial list of 33 terms derived from an initial search of the medical literature in Spanish, a consensus of more than 70% was obtained to designate stroke as: “Enfermedad Vascular Cerebral (EVC)” and ischemic and hemorrhagic stroke as “infarto cerebral” and “hemorragia cerebral,” respectively. Likewise, the so-called “stroke units” were designated as “unidades neurovasculares”. Conclusions: This is the first work that seeks to solve, through a consensus methodology, the great diversity that exists in the Spanish language regarding the terminology of stroke.

Resumen Antecedentes: Existe gran heterogeneidad en cuanto a la traducción y el uso del término stroke en el idioma español, lo cual tiene múltiples implicaciones epidemiológicas, científicas y demográficas. Objetivo: El objetivo de este estudio fue llevar a cabo un ejercicio Delphi acerca de la nomenclatura para el término stroke en un grupo de expertos en neurología vascular en México. Métodos: Se realizó un proceso de consenso en tres fases mediante el método Delphi. Los expertos convocados completaron un cuestionario inicial; los cuestionarios subsecuentes se basaron en los resultados iniciales. El consenso final se validó en otro grupo de investigadores. Resultado: 69 especialistas participaron en la primera ronda y 72% en las tres rondas. De una lista inicial de 33 términos, se obtuvo el consenso de más de 70% para referirse a stroke como enfermedad vascular cerebral. Conclusiones: Este es el primer trabajo que busca resolver la diversidad existente en la terminología para denominar al trastorno que en inglés se conoce como stroke.

Abstract Marquez, G. J.; A. Yañez & D. Ocampo Terraza. 2020. First record of Megalastrum oreocharis (Dryopteridaceae) for Argentina. Darwiniana, nueva serie 8(1): 389-394. Megalastrum oreocharis is cited in Argentina for the first time. Within Megalastrum, this species differs from the others in Misiones province, for the presence of rachis, costae and veins hairs greater than 0.5 mm and echinate spores. The careful study of microcharacters within the genus Megalastrum has become an important tool to find records of new species in Argentina, which contributes to ongoing biological diversity studies.

Resumen Marquez, G. J.; A. Yañez & D. Ocampo Terraza. 2020. Primer registro de Megalastrum oreocharis (Dryopteridaceae) para Argentina. Darwiniana, nueva serie 8(1): 389-394. En el presente trabajo se cita por primera vez en Argentina a Megalastrum oreocharis. Dentro de Megalastrum, esta especie se diferencia de otras por la presencia de pelos mayores a 0,5 mm en el raquis, costas y venas, y esporas equinadas. El estudio minucioso de los microcaracteres dentro del género se ha transformado en una herramienta importante para confirmar el hallazgo de nuevos registros para Argentina, lo que enriquece los proyectos de diversidad biológica en curso.

Resumo Embora a principal causa de anemia seja historicamente relacionada à infecção por Haemonchus contortus, outros agentes infecciosos, como micoplasmas hemotrópicos e patógenos transmitidos por carrapatos, também podem causar quadros anêmicos em ovinos. O presente estudo objetivou investigar infecções relacionadas à anemia em um rebanho de ovinos, na cidade de Bandeirantes, Estado do Paraná, sul do Brasil. Sete (16,6%; 95% CI: 8,32–30,6%) de 42 ovinos foram positivos para hemoplasmas pela PCR do gene 16S rRNA, enquanto todos foram negativos para A. marginale/A. ovis e Babesia/Theileria spp. por ensaios da PCR baseados nos genes msp4 e 18S rRNA, respectivamente. Dois (4,7%; 95% CI: 1,32–15,79%) animais estavam infestados por carrapatos Rhipicephalus microplus. Dos 38 animais nos quais foi realizada a contagem de ovos por grama de fezes (OPG), 24 (63,15%; 95% CI: 47,2–76,6%) apresentaram valores >500 para OPG. A análise filogenética das sequências parciais dos genes 16S rRNA e 23S rRNA de hemoplasmas confirmou a infecção por Mycoplasma ovis. A análise de polimorfismos de um fragmento do gene 16S rRNA mostrou a ocorrência de três genótipos diferentes de M. ovis nos animais. Mycoplasma ovis e nematódeos gastrointestinais ocorrem em ovinos da região nordeste do Estado do Paraná.

Abstract Although anemia has been historically linked to Haemonchus contortus infection, other infectious agents, such as hemotropic mycoplasmas and tick-borne disease pathogens, may also lead to anemic crisis in sheep. This study has aimed to investigate infections related to anemia in a sheep herd from Bandeirantes City, Paraná State, southern Brazil. Seven out of forty-two (16.6%; 95% CI: 8.32–30.6%) sheep were positive for hemoplasmas by a PCR targeting the 16S rRNA gene and all tested negative for A. marginale/A. ovis and Babesia/Theileria spp. by PCR based on msp4 and 18S rRNA genes, respectively. Two (4.7%; 95% CI: 1.32–15.79%) animals were infested with Rhipicephalus microplus ticks. Fecal egg counting was performed in 38 sheep and 24 (63.15%; 95% CI: 47.2–76.6%) presented > 500 eggs per gram. Phylogenetic analysis of partial sequences of the detected hemotropic Mycoplasma sp. 16S and 23S rRNA genes confirmed that the animals were infected with Mycoplasma ovis. Polymorphism analysis of partial 16S rRNA sequences showed three different genotypes of M. ovis infecting sheep assessed in the present study. Mycoplasma ovis and gastrointestinal nematodes occurs in sheep from the northern region of Paraná State.

Resumen Introducción: Se informa que las complicaciones relacionadas con la endoscopía retrógrada endoscópica (CPRE) son tan altas como el 12%, la tasa de perforación intestinal relacionada con la CPRE es de 0,3 al 1,0%, y está relacionada con una mortalidad de hasta 25%. El propósito de este estudio es Revisar nuestra experiencia en 7 años con el manejo de perforaciones duodenales relacionadas a CPRE. Material y métodos: Se realizó una revisión de expedientes de pacientes que experimentaron perforaciones duodenales post-CPRE y que además fueron sometidos a esfinterotomía con precorte. La revisión abarco un periodo de 7 años y se describen como principales resultados el manejo no quirúrgico (incluido endoscópico y médico) y el manejo quirúrgico así como diagnóstico y mortalidad hospitalaria. Resultados: Se encontraron 10 casos de perforación duodenal post-CPRE desde marzo 2012 hasta febrero 2019, se descartaron 2 casos por ser perforaciones debidas a migración de endoprótesis biliar, quedando en total 8 casos para el estudio. 5 mujeres y 3 hombres con una edad promedio de 66 años. La principal indicación del estudio fue el riesgo alto de coledocolitiasis en 50%, El diagnóstico de perforación duodenal se realizó el 100% en un periodo mayor de 24 horas, el estudio mas útil para el diagnóstico fue la Tomografía con contraste. Al 100% de los casos se colocó prótesis biliar plástica l, solo 3 pacientes presentaron pancreatitis post-CPRE y 1 caso requirió revisión por hemorragia post esfinterotomía. 6 casos presentaron perforaciones tipo II, 3 pacientes requirieron cirugía de urgencia, otros 3 solo recibieron manejo medico endoscópico y 2 pacientes requirieron tratamiento paliativo. Estos últimos fueron las únicas 2 defunciones durante el estudio. Conclusiones: La valoración previa del paciente y de los procedimientos de alto riesgo nos permitirían clasificar a los pacientes con alto riesgo de perforación y con ello poder emplear una vigilancia más estrecha para un diagnóstico y tratamiento oportuno, ya que mientras más tarde sea el tratamiento existe mayor morbimortalidad de acuerdo a los reportes en la literatura. Afortunadamente nuestra tasa e perforaciones no es tan alta pero aún sigue siendo una de las complicaciones más temibles para los endoscopistas.

ABSTRACT Introduction: The National Health System, its mission, coverage and characteristics, requires a constant flow of information in order to maintain a high level of knowledge of each of the activities undertaken at all levels for driving management processes and services. A specialist in the use of technologies is necessary in order to allow lead and manage effective decision making in the Health Sector infrastructure. Objective: To analyze the historical behavior of Software Design teaching in Health Information Systems program. Methods: as the main methods of theoretical level: Historical and logical, analysis-synthesis, induction, deduction and systemic approach, within the empirical level: documentary analysis. Results: An assessment of the regulatory documents governing the teaching and learning of software design in the world, Latin America and Cuba, that can be used as a supplementary means of support for the methodological training of teachers of the discipline. Conclusions: The current medical education in Cuba, has made great qualitative and quantitative progress in all aspects of the teaching process, but there are curricular elements that must be addressed in order to increase the quality of the teaching process.

RESUMEN Introducción: El Sistema Nacional de Salud, por su misión, cobertura y características, requiere de un constante flujo informativo, por lo que necesita un personal especializado en el uso de tecnologías que les permita dirigir y gestionar la infraestructura necesaria para la efectiva toma de decisiones en el Sector. Objetivo: Analizar el comportamiento histórico de la enseñanza del diseño de software en la carrera Sistemas de Información en Salud. Métodos: Para la realización de la presente investigación de tipo descriptiva, se utilizaron como principales métodos los de nivel teórico: Histórico-lógico, Análisis-síntesis, Inducción-deducción y Enfoque sistémico, dentro de los de nivel empíricos el de Análisis documental. Resultados: Se obtiene una valoración del análisis realizado a los documentos normativos que rigen el Proceso de Enseñanza y Aprendizaje del diseño de software en el mundo, América Latina y Cuba que puede ser utilizado como medio complementario de apoyo a la preparación metodológica de los profesores de la disciplina Informática. Conclusiones: Existen elementos curriculares que deben ser atendidos con el fin de aumentar la calidad del proceso docente, a pesar de que se han alcanzado grandes avances cualitativos y cuantitativos en todos los aspectos de este proceso.

First record of the genus Actinostachys (Schizaeaceae) for Argentina. The fern Actinostachys pennula (Schizaeaceae) is cited for the first time from Argentina, on the basis of material recently collected in the northeast of Misiones province. It is provided a description of the species, ecological observations, and ÍNustrations of sporophyte and spores.

Se registra por primera vez para la flora Argentina el helecho Actinostachys pennula (Schizaeaceae), sobre la base de material recién recolectado en el nordeste de la provincia de Misiones. Se incluye una descripción de la especie, observaciones ecológicas, e ilustraciones del esporofita y esporas características de la especie.

ABSTRACT The genera of Dennstaedtiaceae have sporophytes with very different morphological characteristics between each other, and this feature has made difficult the systematic circumscription of the family. This reason makes necessary the study of new characters that allow a better understanding of the relations within the group. The spore morphology and wall structure of Blotiella lindeniana, Histiopteris incisa and Paesia glandulosa from the Paranaense Phytogeographic Province were studied using light microscope, and scanning and transmission electron microscope. The exospore has two layers and, according to the species, the exospore surface bears pila, echinae, verrucae, bacula and tubercles. The perispore has two or three layers and its surface is psilate, baculate or rugulate. The variability found in the sculpture of the spores and their stratification and ultrastructure of perispore reflects the morphological differences observed in the sporophyte of the species studied. Additionally, while the stratification and ultrastructure of the exospore is shared by the Dennstaedtiaceae species, their ornamentation could be a character to distinguish species into the clade “hypolepidoide”. The finding of spores with similar characteristics in phylogenetically unrelated families allows us to suggest that palynological features do not have an evolutionary value to establish relationships between groups above the genus level.

Resumo: O teste de tetrazólio (TZ) é uma alternativa aos testes de germinação que, geralmente, demandam de maior tempo de execução. Para sua utilização é necessário o desenvolvimento de metodologias especificas de aplicação, determinando a concentração e o tempo de exposição das sementes ao sal. Assim, com este trabalho busca-se (i) otimizar a aplicação do TZ em sementes florestais de Platymiscium floribundum Vog., Lonchocarpus muehlbergianus Hassl. e Acacia polyphylla DC., reduzindo a subjetividade da interpretação dos resultados e (ii) adequar metodologias para avaliar a qualidade de sementes por meio do TZ. Para a realização dos testes, as sementes foram submetidas a tempos de imersão e concentrações (0,1; 0,5 e 1,0%) em solução de 2, 3, 5 trifenil cloreto de tetrazólio. Cada semente foi avaliada por cor, tamanho e localização das manchas em três zonas de baixo, médio e alto impacto para a capacidade de germinação e, classificada em três classes de vigor. As concentrações e tempo de imersão ideais para cada espécie foram: P. floribundum - 0,5 e 1,0% por 60 minutos; L. muehlbergianus - 0,1% por 6 horas e A. polyphylla - 0,5% por 4 horas. O protocolo e a metodologia apresentaram alta eficiência de acordo com os parâmetros estabelecidos.

Abstract: The tetrazolium (TZ) test is an alternative to conventional germination tests, which usually require longer periods for seed quality evaluation. However, it is necessary to develop specific methodologies for each species, determining the concentration and time of exposure to salt. Thus, the objectives of this study were (i) to optimize the application of tetrazolium in forest seeds of Platymiscium floribundum Vog., Lonchocarpus muehlbergianus Hassl. and Acacia polyphylla DC., with the proposal of an evaluation protocol for tetrazolium test in order to reduce the subjectivity of interpretation and (ii) to adapt standardized methodologies to evaluate the seed quality of forest species using TZ. To perform the tests, the seeds were submitted to immersion times and concentrations (0.1, 0.5 and 1.0%) in solution of 2,3,5-triphenyl tetrazolium chloride. The ideal concentrations and immersion time for each species were: P. floribundum - 0.5 and 1.0% for 60 minutes; L. muehlbergianus - 0,1% for 6 hours and A. polyphylla - 0,5% for 4 hours. Each seed was evaluated by color, size and localization of colored spots in three zones of low, medium and significant impact on germinability and after classified in three vigor classes. The protocol and the proposed methodology presented high efficiency according to the established parameters.

Wind pollination in Asteraceae is well documented only in few tribes. Particularly, in Eupatorieae, apparent anemophily has only been reported in 10 species belonging to the genera Critonia, Decachaeta, Eupatorium, Koanophyllon, and Neohintonia, most of which inhabit North and Central America, with only two species from South America. The genus Acanthostyles has only one species, Acanthostyles buniifolius, which is widely distributed in southern South America. This species shows features that may suggest a pollination mechanism mediated by wind. We analyzed in detail some morphological and palynological traits related to the anemophilous syndrome. As a result, we identified some characters of A. buniifolius associated to wind pollination: presence of loose and pendulous secondary inflorescence with mainly downward oriented small heads, increased of proportion of stigmatic area in relation to the total length of the style branch, acicular style sweeping laxly arranged and wide-caveate, microechinate (= subechinate) pollen. This paper proposes first evidence of possible anemophily for a species of subtribe Dysinaphiinae within the Eupatorieae tribe.

La polinización por el viento en la familia Asteraceae se encuentra documentada en unas pocas tribus. Particularmente en Eupatorieae, sólo se ha reportado aparente anemofilia en 10 especies pertenecientes a los géneros Critonia, Decachaeta, Eupatorium, Koanophyllon y Neohintonia, la mayoría de las cuales crece en América del Norte y Central, con sólo dos especies que alcanzan América del sur. El género Acanthostyles incluye una única especie, Acanthostyles buniifolius, la cual se encuentra ampliamente distribuida en el sur de América del Sur. Esta especie presenta características que sugieren un mecanismo de polinización mediado por el viento. Analizamos en detalle algunos caracteres morfológicos y palinológicos relacionados con el síndrome anemófilo. Como resultado, identificamos algunos atributos asociados con la polinización por el viento: inflorescencia laxa y péndula con capítulos pequeños orientados principalmente hacia abajo, estilo con mayor proporción de área estigmática en relación al largo total de la rama del estilo, pelos barredores del estilo aciculares dispuestos laxamente y polen con amplio cavus, microequinado (=subequinado). Este trabajo aporta las primeras evidencias de la posible anemofilia para una especie de la subtribu Dysinaphiinae, dentro de la tribu Eupatorieae.

Las imágenes hiperespectrales (HSI) son de vital importancia en una amplia gama de aplicaciones, tales como la teledetección, imágenes espaciales, la detección y la exploración de minerales. Desafortunadamente, es difícil adquirir HSI de alta resolución espacio-espectral debido a las limitaciones de los equipos de sensado. Para obtener versiones de HSI de alta calidad se usan técnicas tradicionales de superresolución. Éstas técnicas no permiten el uso directo de la información espacial y espectral que son un factor decisivo para una óptima reconstrucción. En este trabajo se propone la implementación de un novedoso algoritmo de superresolución de una sola imagen hiperespectral. El algoritmo integra la información espacial y espectral en las HSI para realizar una estimación precisa de alta resolución. Esta integración se obtiene mediante el uso de dos tipos de muestreo espacio-espectral y un interpolador tridimensional, que permite aumentar la coherencia de la información inherente en la imagen. Las imágenes resultantes son superiores hasta 2 dB comparas con reconstrucciones obtenidas por enfoques tradicionales.

Hyperspectral imaging (HSI) is used in a wide range of applications such as remote sensing, space imagery, mineral detection, and exploration. Unfortunately, it is difficult to acquire hyperspectral images with high spatial and spectral resolution due to instrument limitations. The super-resolution techniques are used to reconstruct low-resolution hyperspectral images. However, traditional super-resolution (SR) approaches do not allow direct use of both spatial and spectral information, which is a decisive for an optimal reconstruction. This paper proposes a single image SR algorithm for HSI. The algorithm uses the fact that the spatial and spectral information can be integrated to make an accurate estimate of the high-resolution HSI. To achieve this, two types of spatio-spectral downsampling, and a three-dimensional interpolation are proposed in order to increase coherence between the spatial and spectral information. The resulting reconstructions using the proposed method are up to 2 dB better than traditional SR approaches.

A morfologia dos esporos e a ultraestrutura da parede do Microlepia speluncae e Pteridium arachnoideum da Província Paranaense foram analisadas com LM, SEM e TEM e uma análise comparativa foi realizada. Em am bas as espécies, os esporos são cobertos por uma rede tridimensional de cordões ramificados e fundidos, dis postos tangencialmente à superfície, e alguns fios com extremidades livres também são vistos. As espécies foram diferenciadas pela morfologia e a frequência de fusão de fios e redes de distribuição sobre a superfície dos esporos. Em ambas as espécies a exospore é de duas camadas na seção, ambas as camadas são atravessadas por canais únicos ou ramificados. O perisporo é de três camadas na seção: a camada interna é aderida à exospore, a camada do meio é formada por uma rede tridimensional de cordões e a camada exterior é descontínua. A ultraestrutura do perisporo de Microlepia speluncae foi interpretada como formada por subunidades helicoidais exibidas em torno de um canal central. A morfologia dos esporos e ultraestrutura do perisporo permitem diferenciar Microlepia de Pteridium, mas também para os outros gêneros Dennstaedtiaceae que crescem na Província Paranaense. Os resultados obtidos permitem estabelecer relações que nos permitem reconhecer diferentes grupos e nos deu uma nova referência para obter um melhor conhecimento da família.

The spore morphology and wall ultrastructure of Microlepia speluncae and Pteridium arachnoideum from the Paranaense Province were analyzed with LM, SEM and TEM and a comparative analysis was carried out. In both species the spores are covered by a three-dimensional network of threads branched and fused, tangentially arranged to the surface, and some free-end threads are also seen. The species were differentiated by morphology and the frequency of threads fusion and the networks distribution on the surface of the spores. In both species the exospore is two-layered in section, both layers are traversed by single or branched channels. The perispore is three-layered in section: the inner layer is adhered to the exospore, the middle layer is formed of a three-dimensional network of threads and the outer layer is discontinuous. The perispore ultrastructure of Microlepia speluncae was interpreted as formed of helical subunits displayed around a central channel. The spore morphology and perispore ultrastructure allow differentiating Microlepia from Pteridium but also to the other Dennstaedtiaceae genera that grow in the Paranaense Province. The results obtained allow establishing relationships that let us recognize different groups and gave a new reference to get a better knowledge of the family.

The aim of the present study was to enhance the knowledge of the feeding habits of the juvenile component of the population of Southern elephant seals [Mirounga leonina (Linnaeus, 1758)] from Isla 25 de Mayo, South Shetland Islands, age class whose diet information is scarce. A total of 60 individuals were stomach lavaged in the spring - summer seasons of three consecutive years (2003, 2004 and 2005) of which 53.3 % (n = 32) presented food remnants. The Antarctic glacial squid Psychroteuthis glacialis Thiele, 1921 was the dominant prey taxon in terms of frequency of occurrence (68.7%), numerical abundance (60.1%) and biomass (51.5%), contributing 84.1% to the total relative importance index. Other squid prey species of importance were Slosarczykovia circumantartica Lipinski, 2001 in terms of occurrence (37.5%) and numerical abundance (14%) and Moroteuthis knipovitchi Filippova, 1972 in terms of biomass (16%). All identified cephalopod prey taxa are distributed south of the Antarctic Polar Front, except for the squid Martialia hyadesi Rochebrune & Mabille, 1889 which has a circumpolar distribution associated to the Polar Frontal Zone. No significant differences in the sizes of P. glacialis preyed upon by elephant seals were found between sexes and years. However, significant interannual differences were found in the taxonomical composition of their diet. This would be associated with temporal changes in food availability at the foraging areas of seals, which in turn may have been influenced by changes in oceanographic conditions as a result of the El Niño Southern Oscillation (ENSO) phenomenon that occurred during part of the study period. Furthermore, a differential response of males and females to this temporal variation was observed, with the former being also associated to a predation on octopods. This would suggest a sexual segregation in foraging habits of this species from the early stages of its life cycle.

El objetivo del presente estudio fue el de incrementar el conocimiento de los hábitos alimentarios del componente juvenil de la población de elefantes marinos del sur [Mirounga leonina (Linnaeus, 1758)] de Isla 25 de Mayo, Islas Shetland del Sur, clase de edad cuya dieta es poco conocida . Un total de 60 ejemplares fueron sometidos a técnicas de lavaje estomacal durante primavera - verano de tres años consecutivos (2003, 2004 y 2005) de los cuales el 53,3 % (n = 32) presentaba restos alimentarios. El calamar antártico Psychroteuthis glacialis Thiele, 1921 fue el taxón presa dominante en términos de frecuencia de ocurrencia (68,7%), abundancia numérica (60,1%) y biomasa (51,5%), contribuyendo en un 84,1% al índice de importancia relativa total. Otros calamares presa de importancia fueron Slosarczykovia circumantartica Lipinski, 2001, en términos de ocurrencia (37,5%) y de abundancia numérica (14%), y Moroteuthis knipovitchi Filippova, 1972 en términos de biomasa (16%). Todos los taxa presa identificados se distribuyen al sur del Frente Polar Antártico, a excepción de Martialia hyadesi Rochebrune & Mabille, 1889, especie que presenta una distribución subantártica asociada a la Zona del Frente Polar. No hubo diferencias significativas intergenéricas ni interanuales en los tamaños de P. glacialis predados por los elefantes marinos. Sin embargo, se encontraron diferencias interanuales significativas en la composición taxonómica de la dieta. Esto estaría asociado a los cambios temporales en la disponibilidad de alimento en las áreas de forrajeo de los elefantes, que a su vez pudieron estar influenciados por las variaciones en las condiciones oceanográficas, como resultado de la Oscilación Austral del Niño (ENSO) que se produjo durante parte del período de estudio. Por otra parte, se observó cierta respuesta diferencial de machos y hembras a esta variación temporal, estando los primeros asociados a una predación sobre octópodos. Esto sugiere una segregación sexual en los hábitos de forrajeo de esta especie desde etapas tempranas de su ciclo de vida.