Pellet analysis evidences flexibility in the diet of Brown Skua (Stercorarius antarcticus) during breeding at Esperanza/Hope Bay (Antarctic Peninsula)

At Esperanza/Hope Bay, Antarctic Peninsula, breeding Brown Skuas (Stercorarius antarcticus) coexist with a breeding colony of Adélie (Pygoscelis adeliae) and Gentoo (P. papua) penguins. Previously, we reported that the principal prey consumed by Brown Skuas was penguin, however, the contribution of marine resources to their diet was high. Besides, the number of conspecifics that compete for this resource gradually increases across the season. This prompted us to enquire into the ecological factors that may promote the use of marine resources during the breeding cycle. For this, during the 2014–2015 and 2015–2016 seasons, 400 regurgitated pellets were collected over the breeding season for different stages in the nesting cycle: incubation, early and late chick rearing. Prey items were classified according to different categories (penguin, fish, mollusk, and crustacea), and the occurrence frequency of each category was determined. As expected, penguins were the main prey consumed, but the occurrence of fish and mollusks increased for both early and late care of chicks. The flexibility in skua foraging behavior may be related to the changing degree of central place forager, and to the fluctuating energy requirements during each breeding stage. Moreover, the conspicuous decline in penguin availability or accessibility induced by intraspecific competition, may represent an alternative driving force in their foraging behavior over the breeding season.Fil: Ibañez, Andres Esteban. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Morales, Lara Mariel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Torres, D. S.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; ArgentinaFil: Borghello, P.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; ArgentinaFil: Montalti, Diego. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados. Sección Ornitología; Argentin

Physical Properties and Chemical Characterization of Macro- and Micro-Nutriments of Elite Blue Maize Hybrids (Zea mays L.)

Five elite blue maize hybrids and two blue maize landraces were evaluated for various quality characteristics. Hybrids showed physical characteristics demanded by dry-millers and tortilla processors: above 290 g in one hundred-kernel weight test, higher test weight (76.1–78.5 kg hl−1) and lower flotation index (22–61%). Hybrid maize 613 × 27 (9.9%) and 611 × 8 (9.5%) contained the highest protein. Potassium, magnesium, manganese and zinc contents of hybrid maize were higher than landraces by 15, 30, 55 and 41%, respectively. Nutrimental profile showed linoleic acid contents above 50% in 503 × 67, 613 × 27 and 611 × 8 hybrid samples. Lysine levels of landraces and hybrids 503 × 67 (33.9 g kg−1 protein) and 631 × 27 (31.7 g kg−1 protein) were higher than reported for regular white corn (27 g kg−1 protein), as well as the highest tryptophan levels for Chalqueno (6.0 g kg−1 protein) and hybrid 503 × 67 (6.9 g kg−1 protein). Highest protein quality based on its digestibility was found in hybrid 503 × 67. Results indicated that elite blue maize hybrids could be an important source of nutrimental compounds with potential for functional food industries

Notes on the sexual condition of Myriophyllum aquaticum, Haloragaceae Notas sobre la condición sexual de Myriophyllum aquaticum, Haloragaceae

Resumen. Myriophyllum aquaticum (Vell.) Verdc. es nativa de Sudamérica con distribución pantropical. Esta especie ha sido citada como dioica, monoica y polígama. El objetivo de este trabajo es contribuir a la discusión sobre su condición sexual, basada en material de herbario, y apoyada por observaciones de campo. Se examinó material de herbario de Argentina. En la Reserva Natural de Punta Lara (Buenos Aires, Argentina), se muestrearon periódicamente veinte ramas para registrar el sexo de las flores presentes en cada verticilo durante el período de floración de 2002. Tanto en material de herbario, como en el campo, observamos especímenes con ramas con flores femeninas, especímenes con ramas con flores masculinas y especímenes con flores femeninas y masculinas en la misma rama. Algunos de estos materiales presentan frutos. Nuestras observaciones apoyan la idea que M. aquaticum no es una especie estrictamente dioica, al menos en Argentina. Palabras clave: Dioecia; Monoecia; Myriophyllum aquaticum; Punta Lara. Abstract. Myriophyllum aquaticum (Vell.) Verdc. is native of South America and has a pantropical distribution. This species has been cited as dioecious, monoecious and polygamous. The purpose of this paper was to contribute to the discussion of its sexual condition, based on herbarium material, and supported by field observations. Herbarium material from Argentina was examined. Also, twenty branches from the Punta Lara Nature Reserve (Buenos Aires, Argentina) were periodically sampled to record the sex of flowers present on each whorl during the flowering period of 2002. Both in herbarium material and in field, we observed specimens with branches bearing either female or male, and specimens with female and male flowers on the same branch. Some of these materials have also fruits. Our observations support the idea that M. aquaticum is not a strictly dioecious species, at least in Argentina

Physics of Eclipsing Binaries: Heartbeat Stars and Tidally Induced Pulsations

Heartbeat stars are a relatively new class of eccentric ellipsoidal variable first discovered by Kepler. An overview of the current field is given with details of some of the interesting objects identified in our current Kepler sample of 135 heartbeats stars. Three objects that have recently been or are undergoing detailed study are described along with suggestions for further avenues of research. We conclude by discussing why heartbeat stars are an interesting new tool to study tidally induced pulsations and orbital dynamics

Anomalous origin of the left coronary artery with origin in the right coronary artery from a single coronary ostium associated with multivessel coronary artery disease: case report and literature review

The anomalous origin of the coronary arteries is a group of rare congenital heart conditions in which there has been an increase in its diagnosis thanks to more accessible and less invasive imaging techniques such as coronary angiotomography, which allows visualization of the arteries in its entire path in a short exploration interval, with adequate spatial and temporal resolution. The clinical presentation is variable, up to 80% are asymptomatic and the remaining 20% may present arrhythmias, myocardial infarction, heart failure and sudden death. We present the case of a patient with unstable angina in whom an anomalous origin of the left coronary artery (LCA) with origin in the right coronary artery (RCA) from a single coronary ostium associated with multivessel coronary artery disease was diagnosed

A Decade of SN1993J: Discovery of Wavelength Effects in the Expansion Rate

We have studied the growth of the shell-like radio structure of supernova SN1993J in M81 from September 1993 through October 2003 with very-long-baseline interferometry (VLBI) observations at the wavelengths of 3.6, 6, and 18cm. For this purpose, we have developed a method to accurately determine the outer radius (R) of any circularly symmetric compact radio structure like SN1993J. The source structure of SN1993J remains circularly symmetric (with deviations from circularity under 2%) over almost 4000 days. We characterize the decelerated expansion of SN 1993J through approximately day 1500 after explosion with an expansion parameter $m= 0.845\pm0.005$ ($R \propto t^{m}$). However, from that day onwards the expansion is different when observed at 6 and 18cm. Indeed, at 18cm, the expansion can be well characterized by the same $m$ as before day 1500, while at 6cm the expansion appears more decelerated, and is characterized by another expansion parameter, $m_{6}= 0.788\pm0.015$. Therefore, since about day 1500 on, the radio source size has been progressively smaller at 6cm than at 18cm. These findings are in stark contrast to previous reports by other authors on the details of the expansion. In our interpretation the supernova expands with a single expansion parameter, $m= 0.845\pm0.005$, and the 6cm results beyond day 1500 are due to physical effects, perhaps also coupled to instrumental limitations. Two physical effects may be involved: (a) a changing opacity of the ejecta to the 6cm radiation, and (b) a radial decrease of the magnetic field in the emitting region. (Long abstract cut. Please, read full abstract in manuscript).Comment: 21 pages, 19 figures, accepted in A&

Composición de la leche de vacas Holstein suplementadas con caña de azúcar integral y saccharina rústica enriquecida

La composición de la leche asume importancia por tratarse de un alimento de gran valor nutritivo y alto consumo humano. El objetivo de este trabajo fue evaluar el efecto de dos tipos de suplementos a base de caña de azúcar sobre la composición de la leche de vacas Holstein. Se utilizaron dos grupos de diez vacas cada uno, las cuales fueron suplementadas durante seis meses con saccharina rústica enriquecida (grupo A) y caña de azúcar integral (grupo B). Bimestralmente se efectuaron análisis químicos proximales de los alimentos y pruebas de calidad láctea. Los niveles de proteína bruta y fibra cruda de la saccharina empleada (14 y 38,7% respectivamente) se aproximaronn a los reportados en otros trabajos (13,05 y 34,58% respectivamente). Para la caña de azúcar los valores de proteína bruta (6,5%) resultaron más altos que los comunicados por otros autores (2,6–4,7%) pero los de fibra cruda fueron más bajos (32,3%) que los citados por la bibliografía (36,1–48,1%). El promedio de los análisis de leche reveló 3,4% de grasa, 3,1% de proteínas y 5% de lactosa (grupo A) y 3,2% de grasa, 3,1% de proteínas y 4,8% de lactosa (grupo B). Se concluye que la suplementación con saccharina rústica enriquecida aporta mayor cantidad de nutrientes que la caña de azúcar integral y genera mejores índices en la composición de la leche.