147 research outputs found

    Kinematics of gas and stars in circumnuclear star-forming regions of early type spirals

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    (Abbr.) We present high resolution (R~20000) spectra in the blue and the far red of cicumnuclear star-forming regions (CNSFRs) in three early type spirals (NGC3351, NGC2903 and NGC3310) which have allowed the study of the kinematics of stars and ionized gas in these structures and, for the first time, the derivation of their dynamical masses for the first two. In some cases these regions, about 100 to 150 pc in size, are seen to be composed of several individual star clusters with sizes between 1.5 and 4.9 pc estimated from Hubble Space Telescope (HST) images. The stellar dispersions have been obtained from the Calcium triplet (CaT) lines at λλ\lambda\lambda 8494,8542,8662 \AA, while the gas velocity dispersions have been measured by Gaussian fits to the Hβ\beta and [OIII] λλ\lambda\lambda 5007 \AA lines on the high dispersion spectra. Values of the stellar velocity dispersions are between 30 and 68 km/s. We apply the virial theorem to estimate dynamical masses of the clusters, assuming that systems are gravitationally bounded and spherically symmetric, and using previously measured sizes. The measured values of the stellar velocity dispersions yield dynamical masses of the order of 107^7 to 108^8 solar masses for the whole CNSFRs. Stellar and gas velocity dispersions are found to differ by about 20 to 30 km/s with the Hβ\beta emission lines being narrower than both the stellar lines and the [OIII] λλ\lambda\lambda 5007 \AA lines. The twice ionized oxygen, on the other hand, shows velocity dispersions comparable to those shown by stars, in some cases, even larger. We have found indications of the presence of two different kinematical components in the ionized gas of the regions...Comment: 4 pages, proceeding of the meeting "Young massive star clusters - Initial conditions and environments", Granada, Spain, 200

    Actividad antihelmíntica del extracto de Peumus boldus comparada con la piperazina citrato sobre el huevo y larva de Ascaris suum

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    La ascariasis, enfermedad causada por Ascaris es una de las enfermedades con mayor prevalencia en cerdos domésticos de sistemas de producción masiva, siendo responsable de grandes pérdidas económicas. La presente investigación tiene como finalidad comparar el efecto del extracto hidroalcohólico de las hojas de Peumus boldus “Boldo” con el de la piperazina citrato, droga utilizada como antihelmíntico en algunos países, sobre: (i) la embrionación de huevos (formación de la larva), (ii) supervivencia in vitro de larvas L2 y (iii) infectividad in vivo de A. lumbricoides var. suum en ratón, Mus musculus BALB/c. Las hojas de “Boldo” utilizadas fueron importadas de Curicó, (Chile) y el extracto hidroalcohólico se obtuvo mediante el método de maceración. Los huevos de A. lumbricoides var. suum fueron obtenidos de parásitos hembras recolectadas en el Camal de Trujillo (Perú). La investigación se diseñó en tres sistemas: grupo experimental (extracto), control positivo (piperazina) y control negativo (SSF para el sistema de embrionación y la prueba in vivo y medio Minimun Esential Medium (MEM) para la prueba in vitro. El porcentaje de eficacia hallado en cada experimento fue: (i) para la embrionación, 11% en el grupo experimental (1.5mg del extracto), 10% con piperazina (1.5 mg) y 90% en el grupo control (SSF), (ii) para la acción in vitro frente a la L2, 03% en el grupo experimental (0.5 mg/mL del extracto), 02 con piperazina (0.5 mg/mL) y 99% en el grupo control (MEM) y (iii) para la eficacia in vivo, 0.05% en el grupo experimental (2 mg/kg de estracto), 0.05 en el control positivo (1.65 mg/kg de piperazina) y 91% en control (SSF). En todos los casos el porcentaje del grupo experimental y el control positivo no se diferenciaron estadísticamente (p<0,05) por lo que se concluye que tienen efecto similar. Palabras clave: Ascariasis, Piperazina citrato, antihelmíntico

    Callus induction, clonal propagation and in vitro germplasm conservation of ‘hualtaco’ Loxopterygium huasango Spruce ex Engl. (Anacardiaceae)

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    Loxopterygium huasango Spruce ex Engl., of the Anacardiaceae family, classified critically endangered, is a forest tree with considerable value in the Seasonally Dry Tropical Forest (SDTF) in the northwest of Peru and south of Ecuador. The aim of the study was callus induction, propagation and germplasm conservation using in vitro tissue culture techniques. In vitro seed germination (90%) was obtained on Murashige and Skoog (MS) medium supplemented with 5.0 mg/L-1 GA3. The cotyledonal nodes of seedlings were used as explants to initiate the growth of the apical shoots, in culture medium with the IAA-GA3 interactions, without observing growth of the axillary buds. The highest rate of friable callus induction (100%) was recorded on MS medium containing 0.1 to 5.0 mg/L-1 2,4-D in cotyledons and hypocotyls explants after 30 to 45 days of culture. The profuse roots formation was the only morphogenic response (10.8 to 13.8%) on MS medium with 0.5 mg/L-1 IAA, 0.5 mg/L-1 IAA 2.0 mg/L-1 BAP, KIN or 2iP or 2.0 mg/L-1 BAP, KIN or 2iP. The germplasm conservation of apical buds and nodal segments was achieved with 2.0 mg/L-1 AgNO3. This method could be used to conserve elite genotypes, rapid production of roots and establishment of cellular suspension for secondary compounds production.Loxopterygium huasango Spruce ex Engl., of the Anacardiaceae family, classified critically endangered, is a forest tree with considerable value in the Seasonally Dry Tropical Forest (SDTF) in the northwest of Peru and south of Ecuador. The aim of the study was callus induction, propagation and germplasm conservation using in vitro tissue culture techniques. In vitro seed germination (90%) was obtained on Murashige and Skoog (MS) medium supplemented with 5.0 mg/L-1 GA3. The cotyledonal nodes of seedlings were used as explants to initiate the growth of the apical shoots, in culture medium with the IAA-GA3 interactions, without observing growth of the axillary buds. The highest rate of friable callus induction (100%) was recorded on MS medium containing 0.1 to 5.0 mg/L-1 2,4-D in cotyledons and hypocotyls explants after 30 to 45 days of culture. The profuse roots formation was the only morphogenic response (10.8 to 13.8%) on MS medium with 0.5 mg/L-1 IAA, 0.5 mg/L-1 IAA 2.0 mg/L-1 BAP, KIN or 2iP or 2.0 mg/L-1 BAP, KIN or 2iP. The germplasm conservation of apical buds and nodal segments was achieved with 2.0 mg/L-1 AgNO3. This method could be used to conserve elite genotypes, rapid production of roots and establishment of cellular suspension for secondary compounds production

    Carbon footprint of lamb and Wool production at farm gate and the regional sale in southern Patagonia

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    Natural steppe grasslands are the principal food resource for sheep in the Patagonia region, reared for meat and wool. However, there is currently a concern about the relationship between ruminant livestock and climate change due to its contribution to anthropogenic greenhouse gas (GHG) emissions. The objective of this study was to determine the carbon footprints (CF) of sheep meat (lamb) and wool on a range of farms using empirical data collected on farm and then upscaled to the regional scale using models that use topographic, climatic, and vegetation indices as independent variables. At the regional level, the total CF of lamb and wool (the combination of emissions produced on farm, via transport, and via industrial processing) varied from 10.64 to 41.32 kg CO2-eq/kg for lamb meat (carcass) and from 7.83 to 18.70 kg CO2-eq/kg for fine-grade wool. For both, the predominant contribution was from primary production on-farm (75–90%), followed by industrial processing (2–15%), and transportation. We used multiple regression models to produce maps of lamb and wool CF at farm gate across Santa Cruz province. The model for variation of lamb CF explained 95% of the variance on the data and the most significant predictor variables were temperature seasonality and normalized difference vegetation index (NDVI, dimensionless). The most important variables for the model of CF of greasy wool production at farm gate were isothermality, temperature seasonality, and NDVI explained 98%. The lowest CF values of both products (lamb and wool) were located in more productive grasslands. The successful management of livestock GHG emissions becomes an important challenge to the scientific, commercial, and policy communities. The results of CF for lamb and wool production found in the present work assist in characterizing the greenhouse gas emissions profile of livestock products in Southern Patagonia by providing a baseline against which mitigation actions can be planned and progress monitoredEEA SANTA CRUZFil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral (UNPA). Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Argentina.Fil: Rosas, Yamina Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Centro Austral de Investigaciones Científicas (CADIC). Ushuaia, Tierra del Fuego; Argentina.Fil: Ladd, Brenton. Universidad Científica del Sur. Escuela de Agroforestería. Lima; Perú.Fil: Díaz-Delgado, Ricardo. Estación Biológica de Doñana (CSIC). Laboratorio de SIG y Teledetección. Sevilla; España.Fil: Martínez Pastur, Guillermo J. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Centro Austral de Investigaciones Científicas (CADIC).Ushuaia, Tierra del Fuego; Argentina

    Cross-Layer Optimization for Video-streaming Transmission with QoS over Ad Hoc Networks: A Holistic Approach

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    In this paper we present ViStA-XL, a Cross-Layer (XL) design aiming to optimize the overall performance of videostreaming services over Mobile Ad Hoc Networks (MANETs). The idea relies on applying optimization strategies to different network layers in a holistic way. In ViStA-XL, a real-time Optimizer (XLO) periodically gathers information of the state of node and network from different layers of the stack of protocols, takes optimization decisions, and then modifies some parameters of the protocols accordingly. In addition, our proposal exploits path diversity through MM-DSR (Multipath MultimediaDynamic Source Routing) protocol as a means to reinforce the Quality of Service (QoS) provision to multi-layer encoded videostreaming applications, by protecting the most important video information packets, balancing the load and decreasing the endto-end delay. To show the advantages of our approach, we have developed and tested an algorithm based on ViStA-XL. Simulation results show that our proposed network design can improve the performance of video-streaming transmissions over MANETs in spite of frequent changes in network and node operating conditions

    In vitro tissue culture in plants propagation and germplasm conservation of economically important species in Peru

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    Plant biotechnology is one of the most important tools presently available and methods to genetically manipulate plants to exhibit greater productivity, tolerance to physical and chemical stress, and resistance to pests and diseases have been developed in recent decades. In vitro plant tissue culture has contributed significantly to this purpose. The objective of this study is to apply various techniques developed by in vitro tissue culture in seed germination, meristem culture for virus elimination, micropropagation, conservation, international transfer of germplasm, and induction of various morphogenic processes that lead to the genetic variability known as somaclonal variation. The application of this set of biotechnological techniques, in crops such as cassava, sweet potato, potato, native forest species as Cedrela odorata, Ficus spp. Loxopterygium huasango, and others, sugar cane, rice, pineapple, among other haves made it possible to meet, as a matter of improvement, several of the essential needs of farmers in the region of northern Peru. The development of these technologies will allow their wide application not only in the propagation, genetic improvement and conservation of species of economic importance, food and medicine, but also in the forest species of the seasonally dry tropical forest of northern Peru

    Micropropagación y conservación de germoplasma de Ficus americana Aubl. y F. obtusifolia Kunth de Lambayeque (Perú)

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    Ficus americana and F. obtusifolia are among the most important tree species in Seasonally Dry Tropical Forests (SDTF) due to their evergreen condition and high levels of biomass. However, the SDTF of Lambayeque and northern Peru is greatly diminishing due to the advance of migratory agriculture, illegal mining, and deforestation. The objective of this work was to study the taxonomic aspects of both species, as well as seed germination, micropropagation, and in vitro germplasm conservation. Seed germination was 100% for both species up to three months after collection. As for micropropagation, rooting, and germplasm conservation, the Piper culture medium was effective, as it was constituted by MS mineral salts with 0.02 mg.L-1 IAA and 0.02 mg.L-1 GA3. In vitro germplasm conservation lasted more than 24 months for both species. Acclimatization under greenhouse conditions reached 50% survival for both species.Ficus americana y F. obtusifolia, se encuentran entre las especies arbóreas más importantes de los Bosques Tropicales Estacionalmente Secos (BTES) por su condición de siempre verdes y sus altos niveles de biomasa. Sin embargo, el BTES de Lambayeque y el norte de Perú está disminuyendo enormemente debido al avance de la agricultura migratoria, la minería ilegal y la deforestación. El objetivo de este trabajo fue estudiar los aspectos taxonómicos de ambas especies, así como la germinación de semillas, la micropropagación y la conservación de germoplasma in vitro. La germinación de semillas fue de 100 % en ambas especies hasta tres meses después de la recolección. Respecto a la micropropagación, el enraizamiento y la conservación de germoplasma, el medio de cultivo de Piper resultó efectivo, el cual está conformado por sales minerales MS con IAA 0.02 mg.L-1 y GA3 0.02 mg.L-1. La conservación in vitro de germoplasma duró más de 24 meses en ambas especies. La aclimatación en condiciones de invernadero alcanzó 50 % de supervivencia en ambas especies

    Low cost indoor ultrasonic positioning implemented in FPGA

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    Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. A. Sánchez, S. Elvira, Á. de Castro, G. Gonzalez-de-Rivera, R. Ribalda, J. Garrido, "Low cost indoor ultrasonic positioning implemented in FPGA", 35th Annual Conference of IEEEIndustrial Electronics, 2009. IECON '09, Porto (Portugal), 2009, pp. 2709 - 2714This paper presents a low cost indoor ultrasonic-based positioning system. This system allows the mobile nodes of a Wireless Sensor Network to know their location using radiofrequency and ultrasonics. To achieve this goal, a matrix of transmitting anchor points is installed whereas the mobile nodes receive these transmitted signals and estimate the time-of-flight of the ultrasonic signals. Using two time-of-flight measurements and trilateration equations, the location of the mobile nodes can be inferred in a 2-D space.This work has been partially supported by the CCG08-UAM/TIC-4258 project of the Comunidad de Madrid and UAM

    Protocol for ex vitro and in vitro micropropagation of Cucurbita moschata and C. ecuadorensis, native to Peru and Ecuador, of nutritional and medicinal importance

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    Cucurbitaceae species constitute a family with a wide worldwide distribution and great nutritional and medicinal importance. The Cucurbita genus is the most important of the family with valuable species such as C. maxima and C. moschata. However, the large-scale production of sex specific plants using the conventional propagation methods has various limitations. The tissue culture such as micropropagation can help overcome these limitations. The aim of this study was to establish a protocol for ex vitro and in vitro clonal propagation of two varieties of Cucurbita moschata: ‘loche’, a variety of commercial vegetative propagation and endemic in Lambayeque, and ‘chuyán’ another variety of very restricted cultivation in some Andean regions of the north of the Peru. Likewise, the in vitro propagation of ‘chisguín’ (C. ecuadorensis), a threatened endemic wild species from the coast of Ecuador. ‘Loche’ was propagated ex vitro by microcutting with a node and leaf, and micropropagated in MS culture medium supplemented with 0.02 mg L-1 IAA and 0.02 mg L-1 GA3. Seedlings of ‘chuyán’ and ‘chisguin’ were micropropagated in MS with with 0.02 mg L-1 IAA, 0.5 mg L-1 BAP and 0.02 mg L-1 GA3. This study constitutes the first report on micropropagation of Peruvian and Ecuadorian varieties and species of the Cucurbita genus

    Efecto de cultivos piscícolas en los sedimentos y la proliferación de comunidades bacterianas nitrificantes en el lago Guamuez, Colombia

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    Fish farming modifies the sediments and the microbiota in water bodies due to supplementary feed residues, chemical substances, and wastes from the metabolism of animals under production. The current study determined the effect of extensive, semi-intensive, and intensive production of rainbow trout (Oncorhynchus mykiss) in sediments, and the proliferation of nitrifying bacterial communities. Total nitrogen, total phosphorus, total organic carbon, and organic matter, and their relationship with nitrifying bacteria (ammonia-oxidizing bacteria-AOB and nitrite-oxidizing bacteria-NOB) were analyzed in the sediment of Lake Guamuez, located in the department of Nariño, Colombia. The data collected were subjected to analyses of variance (ANOVA) and multiple correlation using the Statgraphics Centurion XV software. The variables evaluated showed significant differences (p < 0.05) between the three fish farming systems and the control point. A high and positive correlation was found between nitrifying bacteria and nitrogen compounds, organic matter, and phosphorous in the sediment. This study concluded that the presence of nitrifying bacteria depends on the amount of existing nitrogen compounds and organic matter in the sediment, and increases as the production system intensifies.La piscicultura altera los sedimentos y la microbiota en cuerpos de agua debido a los residuos de concentrados, sustancias químicas y desechos provenientes del metabolismo de los animales en producción. El presente estudio determinó el efecto de la producción extensiva, semiintensiva e intensiva de trucha arcoíris (Oncorhynchus mykiss) en los sedimentos y la proliferación de comunidades bacterianas nitrificantes. Se analizó nitrógeno total, fósforo total, carbono orgánico total y materia orgánica, y su relación con la presencia de bacterias nitrificantes (bacterias oxidantes de amonio [BOA] y bacterias oxidantes de nitritos [BON]) en el sedimento del lago Guamuez, ubicado en el departamento de Nariño, Colombia. Los datos recolectados fueron sometidos a un análisis de varianza (ANOVA) y de correlación múltiple, usando el software Statgraphics Centurion XV. Las variables evaluadas presentaron diferencias significativas (p < 0,05) entre los tres sistemas de cultivo y el punto control. Se encontró una correlación alta y positiva entre las bacterias nitrificantes y los compuestos nitrogenados, la materia orgánica y el fósforo medidos en el sedimento. Se concluyó que la presencia de bacterias nitrificantes depende de las cantidades de compuestos nitrogenados y materia orgánica existentes en el sedimento e incrementa a medida que se intensifica el sistema productivo
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