403 research outputs found

    A deep dive into NGC 604 with Gemini/NIRI imaging

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    The giant HII region NGC 604 constitutes a complex and rich population to studying detail many aspects of massive star formation, such as their environments and physical conditions, the evolutionary processes involved, the initial mass function for massive stars and star-formation rates, among many others. Here, we present our first results of a near-infrared study of NGC 604 performed with NIRI images obtained with Gemini North. Based on deep JHK photometry, 164 sources showing infrared excess were detected, pointing to the places where we should look for star-formation processes currently taking place. In addition, the color-color diagram reveals a great number of objects that could be giant/supergiant stars or unresolved, small, tight clusters. A extinction map obtained based on narrow-band images is also shown.Comment: 4 pages, 4 figures. To appear in the proceedings of IAU Symposium 266, Star Clusters: Basic Galactic Building Blocks Throughout Time and Space, eds. R. de Grijs and J. Lepin

    UMD Banach spaces and square functions associated with heat semigroups for Schr\"odinger and Laguerre operators

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    In this paper we define square functions (also called Littlewood-Paley-Stein functions) associated with heat semigroups for Schr\"odinger and Laguerre operators acting on functions which take values in UMD Banach spaces. We extend classical (scalar) L^p-boundedness properties for the square functions to our Banach valued setting by using \gamma-radonifying operators. We also prove that these L^p-boundedness properties of the square functions actually characterize the Banach spaces having the UMD property

    LpL^p-boundedness properties for the maximal operators for semigroups associated with Bessel and Laguerre operators

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    In this paper we prove that the generalized (in the sense of Caffarelli and Calder\'on) maximal operators associated with heat semigroups for Bessel and Laguerre operators are weak type (1,1). Our results include other known ones and our proofs are simpler than the ones for the known special cases.Comment: 8 page

    Application of the QCM in lead acid batteries electrolyte measurements

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    AbstractThis paper describes the application of a Quartz Crystal Microbalance (QCM) sensor in density-viscosity measurements of the electrolyte of the lead acid batteries. In battery applications, especially in automotive applications, submarines and remote communication systems it is necessary to know the state of charge of the batteries in order to manage them efficiently [1]. One of the physical parameters with information about the state of charge is the electrolyte density; the product ηρ1/2 as well varies with the state of charge [2]. Due the quartz crystal oscillator frequency depends on the density and the viscosity (1), it is possible to measure the electrolyte density changes by means of a QCM sensor. The frequency shift is monitoring in solutions with H2SO4 concentration in the battery electrolyte range. Furthermore, real time experiments are conducted, placing the quartz crystal inside the battery cell

    NOTAS SOBRE LA BIOLOGÍA REPRODUCTIVA Y EL CICLO ANUAL DEL ATAJACAMINOS ALA NEGRA (ELEOTHREPTUS ANOMALUS) EN ARGENTINA

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    Resumen ∙ El Atajacaminos Ala Negra (Eleothreptus anomalus) es una especie amenazada cuya biología reproductiva es casi desconocida. En la Reserva Natural Rincón de Santa María (Corrientes, Argentina) capturamos adultos entre 2012 y 2019. Realizamos 47 capturas de hembras y 209 de machos, de los cuales 13 hembras y ningún macho tenían parche incubatorio. La temporada reproductiva comenzó en agosto con marcada actividad sonora (mecánica y vocal) por parte de los machos en reuniones de tipo leks. Adultos en estado reproductivo se encontraron entre octubre y enero cuando aún capturamos hembras con parches incubatorios y juveniles dependientes. Colocamos radiotransmisores a dos hembras con parche incubatorio. Una hembra con radiotransmisor hizo dos posturas con una diferencia de 12 días y 361 m de distancia entre sí, pero ambas fueron depredadas. Las posturas fueron de uno y dos huevos aunque es posible que la primera puesta haya sido depredada antes de completarse. Los huevos eran de color blanco cremoso con manchas y pintas marrones rojizas y manchas y placas grises de variable tamaño, en toda la superficie. La densidad y distribución de las marcas variaba entre los huevos, incluso en una misma nidada. Las medidas y pesos de los huevos fueron 27,3 x 21,9 mm, 7,2 g; 26,6 x 20,8 mm, 6,2 g; y 25,8 x 21,1 mm, 6,3 g. Los huevos fueron puestos directamente sobre (1) pasto seco aplastado, rodeado de pastizal nativo de 2,2 m de alto con algunas matas de Baccharis dracunculifolia y (2) en tierra desnuda arriba de un tacurú (nido viejo de hormiga carpintera, Camponotus sp.) de unos 50 cm de alto, rodeado de pastizal nativo inundado. Es importante confirmar el cuidado uniparental en Eleothreptus anomalus y poner a prueba la hipótesis de un sistema de apareamiento tipo lek como se ha propuesto para su único congénere el Atajacaminos Ala Blanca (Eleothreptus candicans).Abstract ∙ Notes on reproductive biology and annual cycle of the Sickle-winged Nightjar (Eleothreptus anomalus) in Argentina The Sickle-winged Nightjar (Eleothreptus anomalus) is a threatened species whose reproductive biology is almost unknown. At Reserva Natural Rincón de Santa María (Corrientes, Argentina), we captured adults between 2012 and 2019. We made 47 captures of females and 209 of males, of which 13 females and no males had brood patches. The reproductive period began in August with marked production of sounds (mechanical and vocal) by males in lek-like groupings. Adults in reproductive condition were found between October and January when we still captured females with brood patches and dependent juveniles. We attached radio transmitters to two females with brood patches. One radio-tagged female laid two clutches with a difference of 12 days and separated by 361 m, but both were depredated. The clutches contained one and two eggs, respectively, although it is possible that the first clutch was depredated before it was completed. The eggs were creamy white with reddish-brown patches and spots, and grey patches of variable size, all over the surface. The density and distribution of markings varied among eggs, even within the same clutch. Egg measurements and weights were 27.3 x 21.9 mm, 7.2 g; 26.6 x 20.8 mm, 6.2 g; and 25.8 x 21.1 mm, 6.3 g. Eggs were laid directly on (1) crushed dry grass, surrounded by native grassland, c. 2.2 m tall, with some Baccharis dracunculifolia shrubs and (2) on bare earth atop an old nest of Camponotus sp. ants, about 50 cm high, surrounded by flooded native grassland. It is important to confirm uniparental care in the Sickle-winged Nightjar and test the hypothesis of a lek-mating system as proposed for its only congener, the White-winged Nightjar (Eleothreptus candicans)

    γ-Radonifying operators and UMD-valued Littlewood–Paley–Stein functions in the Hermite setting on BMO and Hardy spaces

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    AbstractIn this paper we study Littlewood–Paley–Stein functions associated with the Poisson semigroup for the Hermite operator on functions with values in a UMD Banach space B. If we denote by H the Hilbert space L2((0,∞),dt/t), γ(H,B) represents the space of γ-radonifying operators from H into B. We prove that the Hermite square function defines bounded operators from BMOL(Rn,B) (respectively, HL1(Rn,B)) into BMOL(Rn,γ(H,B)) (respectively, HL1(Rn,γ(H,B))), where BMOL and HL1 denote BMO and Hardy spaces in the Hermite setting. Also, we obtain equivalent norms in BMOL(Rn,B) and HL1(Rn,B) by using Littlewood–Paley–Stein functions. As a consequence of our results, we establish new characterizations of the UMD Banach spaces

    Culture Medium Factorial Design Optimization for Fibrinolytic Enzymes Production by Bionectria sp.

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    Thrombotic diseases can be clinically treated with fibrinolytic enzymes and many attempts have been made at laboratory level to increase fibrinolytic enzymes production from microbial sources and to reduce the process cost, including culture medium design, optimization of environmental conditions, and over expression with genetically modified strains. In this contribution we present the optimization of culture medium composition and incubation temperature for fibrinolytic enzyme production by Bionectria sp., a selected fungal strain from Las Yungas (Tucumán). Optimization was carried out at Erlenmeyer scale (100-mL working volume) via factorial design methodology. All trials included a common mineral base (%, w/v: NaCl 0.2, KH2PO4 0.05, MgSO4·7H2O 0.05). According to four factorial designs it could be demonstrated the convenience of using soy peptone as N-source, glucose as C-source, and the possibility to eliminate starch, meat peptone and meat extract from original medium composition, whilst 25°C was selected as the optimal incubation temperature. Results showed that culture medium could be successfully optimized by factorial design, achieving a reduction in the production process costs by means of a decrease in culture medium components, the improvement in culture broth rheology, mycelial morphology and mass/energy transfer, and the subsequent two-fold enhancement in productivity.Fil: Arnau, Victor Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Rovati, Jose Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Figueroa, L. I. C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Fariña, Julia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaXLVI Reunión Anual Sociedad Argentina de Investigaciones Bioquímicas y MolecularesPuerto Madryn, Chubut, ArgentinaArgentinaSociedad Argentina de Investigaciones Bioquímicas y Moleculare
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