963 research outputs found
Cryopreservation of embryogenic cell suspensions of the Spanish grapevine cultivars ‘Albariño’ and ‘Tempranillo’
Embryogenic cell suspensions of two elite Spanish grapevine cultivars (‘Albariño’ and ‘Tempranillo’) were successfully cryopreserved by encapsulation-dehydration. The method implied the encapsulation of cells in alginate beads, subsequent culture in liquid medium with 1 M sucrose for 4 days, and desiccation for 2-4 h in the flow of a laminar-flow bench, before immersing in liquid nitrogen. With this simple method, up to 50 % of cell viability in the cryopreserved beads was measured (using the triphenyl tetrazolium method), which corresponded to vigorous growth of 100 % of beads after culture on semi-solid medium. The cryopreserved encapsulated cells were successfully used for initiation of new cell suspensions and their embryogenic capacity was studied. This cryopreservation method is an advance to store ready-to-use competent embryogenic tissue for grapevine genetic transformation projects
The anatomy of urban social networks and its implications in the searchability problem
The appearance of large geolocated communication datasets has recently
increased our understanding of how social networks relate to their physical
space. However, many recurrently reported properties, such as the spatial
clustering of network communities, have not yet been systematically tested at
different scales. In this work we analyze the social network structure of over
25 million phone users from three countries at three different scales: country,
provinces and cities. We consistently find that this last urban scenario
presents significant differences to common knowledge about social networks.
First, the emergence of a giant component in the network seems to be controlled
by whether or not the network spans over the entire urban border, almost
independently of the population or geographic extension of the city. Second,
urban communities are much less geographically clustered than expected. These
two findings shed new light on the widely-studied searchability in
self-organized networks. By exhaustive simulation of decentralized search
strategies we conclude that urban networks are searchable not through
geographical proximity as their country-wide counterparts, but through an
homophily-driven community structure
La 2F1-transformada índice
Estudio de una transformación integral que pertenece a la clase de transformadas de tipo índice (index transforms). Se tratan: las propiedades clásicas de esta transformación, el estudio distribucional, tanto por el denominado método del núcleo como por el del operador adjunto, una convolución tanto para la transformada clásica como para la generalizada, y aplicacione
Data on records of environmental phenomena using low-cost sensors in vineyard smallholdings
Inadequate weather conditions are one of the main threats to the correct development of sensitive crops, where a bad situation can lead to greater stress on plants and their weakness against various diseases. This statement is especially decisive in the cultivation of the vineyard. Meteorological monitoring of vineyard parcels is vital to detect and prevent possible fungal diseases. The development of new Information and Communication Technologies, linked to the Smart Farming movement, together with the reduced cost of electronic components, have favoured a greater availability of meteorological monitoring stations to get to know first-class hand the state of the vineyard smallholdings. This work provides a set of over 750,000 environmental raw data records collected by low-cost Internet of Things nodes, primarily located within vineyard smallholdings. The published observations were collected between 2018-04-01 and 2018-10-31 and were validated in previous research to determine the data's reliability
Chasma Boreale, Mars: A Sapping and Outflow Channel with a Tectono-thermal Origin
A detailed geomorphological study of Chasma Boreale, a widely known feature of Mars’ north polar cap, has been carried out for the first time, along with a quantitative paleohydro logical model. It is concluded that the chasma was eroded by a flow whose discharge was on the order of magnitude of 109 m sec21. This catastrophic flow is thought to have been preceded
by a powerful sapping process, caused by a tectonic control in the distribution and present aspect of most of the polar troughs. This tectonic forcing probably played a major role in the inception of not only Chasma Boreale but also
other polar reentrants as wel
Escalas de respuesta tipo Likert. ¿Es relevante la alternativa 'indiferente'?
En tests de actitudes y de personalidad es frecuente utilizar escalas de respuesta tipo Likert. En este tipo de escalas es frecuente también que se presente una catego-ría intermedia. Esta categoría representa una posición intermedia a lo largo del continuo y entre las categorías adyacentes. El presente estudio evalúa si las categorías de las escalas de respuesta de una serie de cuestionarios frecuentemente utilizados en la evaluación organizacional se presentan realmente ordenadas, tal y como asume el sistema de puntuación empleado. Asimismo, se evalúa si la categoría intermedia ("indiferente") es relevante en términos de probabilidad de respuesta. Los cuestionarios analizados presentan una escala de respuesta tipo Likert de cinco puntos. Para lograr los objetivos propuestos, se ha aj ustado el modelo nominal de Bock (1972). Los resultados obtenidos indican que si bien las categorías de respuesta aparecen ordenadas, la categoría intermedia"indiferente" no es relevante, es decir, en ningún intervalo de valores del rasgo latente aparece como la alternativa que presenta una mayor probabilidad de respuesta. Estos resultados sugieren eliminar la citada categoría de respuesta de las escalas de respuesta empleadas
Modelo experimental de colocación de catéter intratecal lumbar para anestesia espinal en perros
Aunque existe controversia entre Corning y Bier, el primer caso de anestesia espinal se publica en el año 1885, cuando Cornig, accidentalmente, realiza un bloqueo espinal en un perro con cocaína. Desde entonces, la anestesia espinal probablemente ha sido la técnica regional más comúnmente utilizada en la moderna anestesia. Aunque se ha escrito mucho en lo relativo a dicha técnica: aplicaciones, complicaciones..., son pocos los estudios controlados, particularmente en animales donde ha sido posible mantener unas condiciones experimentales estandarizadas. Aún así, han sido descritos métodos experimentales de anestesia espinal 6-11 y epidural12-19 usando la implantación de catéteres en el perro, gato, oveja, rata y humanos. En la gran mayoría de los casos el acceso al espacio subaracnoideo se realiza quirúrgicamente vía occipital (se ha hecho en otras especies como en rata), llegando hasta la cisterna magna, donde puede quedar colocado el catéter, o bien prolongarlo hasta nivel torácico, lumbar. El presente estudio describe un modelo de implantación de catéter intradural en perros, con abordaje lumbar, con técnica quirúrgica previa y con control radioscópico
Virtual placements for informatics students in open source business across Europe
[ES] European Project has the aim of establishing sustainable processes to build knowledge partnerships between Higher Education and companies to collaborate on resolving authentic business problems through open innovation mediated by the use
of Open Source Software. To achieve this, VALS builds knowledge partnerships between Higher Education and companies who work together on resolving authentic business problems through open innovation. The innovative approach is to
leverage virtual placements of informatics students in companies in order to foster entrepreneurial skills and attitudes, and to make use of the results to establish new learning and teaching methods. This results in the Semester of Code initiative, a set of
methods and processes for creating and managing a real virtual placement, and for integrating this into innovative teaching and learning strategy. To show these methods and processes, this paper describes the general methodology designed to perform the
Semester of Code, as well as several guidelines on how to develop the software that will support this process. Also describes a real adaptation of theoretical approach of this whole process in the case of an Academic Institution, including comprehensively all
the issues affecting the process implementation in a real context
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