8,441 research outputs found
Directed Random Markets: Connectivity determines Money
Boltzmann-Gibbs distribution arises as the statistical equilibrium
probability distribution of money among the agents of a closed economic system
where random and undirected exchanges are allowed. When considering a model
with uniform savings in the exchanges, the final distribution is close to the
gamma family. In this work, we implement these exchange rules on networks and
we find that these stationary probability distributions are robust and they are
not affected by the topology of the underlying network. We introduce a new
family of interactions: random but directed ones. In this case, it is found the
topology to be determinant and the mean money per economic agent is related to
the degree of the node representing the agent in the network. The relation
between the mean money per economic agent and its degree is shown to be linear.Comment: 14 pages, 6 figure
Kinematic study of planetary nebulae in NGC 6822
By measuring precise radial velocities of planetary nebulae (which belong to
the intermediate age population), H II regions, and A-type supergiant stars
(which are members of the young population) in NGC 6822, we aim to determine if
both types of population share the kinematics of the disk of H I found in this
galaxy.
Spectroscopic data for four planetary nebulae were obtained with the high
spectral resolution spectrograph Magellan Inamori Kyocera Echelle (MIKE) on the
Magellan telescope at Las Campanas Observatory. Data for other three PNe and
one H II region were obtained from the SPM Catalog of Extragalactic Planetary
Nebulae which employed the Manchester Echelle Spectrometer attached to the 2.1m
telescope at the Observatorio Astron\'omico Nacional, M\'exico. In the
wavelength calibrated spectra, the heliocentric radial velocities were measured
with a precision better than 5-6 km s. Data for three additional H II
regions and a couple of A-type supergiant stars were collected from the
literature. The heliocentric radial velocities of the different objects were
compared to the velocities of the H i disk at the same position.
From the analysis of radial velocities it is found that H II regions and
A-type supergiants do share the kinematics of the H I disk at the same
position, as expected for these young objects. On the contrary, planetary
nebula velocities differ significantly from that of the H I at the same
position. The kinematics of planetary nebulae is independent from the young
population kinematics and it is closer to the behavior shown by carbon stars,
which are intermediate-age members of the stellar spheroid existing in this
galaxy. Our results are confirming that there are at least two very different
kinematical systems in NGC 6822
Comparación entre foraminíferos bentónicos e indicadores geoquímicos en depósitos de plataforma del Jurásico superior del Prebético (Sur de España)
Comparison of the stratigraphic distribution of major and trace elements, used as proxies for palaeoproductivity and redox conditions, and benthic foraminifera from Oxfordian shelf deposits of the External Prebetic (Betic Cordillera, South Spain) allows us to recognise two sedimentary cycles, both characterised by initial enhanced productivity and decreasing oxygen availability in the seabottom, and a subsequent decreasing productivity with a recovering in oxygenation during the second half of each cycle. Dysoxic conditions appear to coincide with maximums in marine surface productivity, thus suggesting that oxygen depletion may be linked to greater consumption rather than restricted circulation. The boundary between the two cycles is characterised by low contents of redox-sensitive elements and lower TOC content and Sr/Al, P/Ti, Ca/Al and Ba/Al ratios, indicating well oxygenated sea-bottom, lower productivity and lower organic matter accumulation. The geochemical proxies have also revealed as a valuable tool for interpreting the stratigraphic fluctuations of benthic foraminiferal assemblages, as well as for evaluating the palaeoecology of the main genera. Spirillina is adversely influenced by oxygen depletion independently of food availability. Ophthalmidium presents very good correspondence with palaeoproductivity fluctuations, and tolerated low oxygen levels in the sediment-water interface. Reophax was an opportunist that proliferated after adverse conditions when oxygenation and food availability were limiting factors. The variability in the microhabitat depth inside the sediment of Reophax favoured adaptation to adverse conditions. Lenticulina shows behaviour similar to Reophax. Finally, Ammobaculites shows a low degree of relation with the palaeoproductivity proxies, and is intolerant with respect to low oxygen values in shallow infaunal microhabitatsLa comparación de la distribución estratigráfica de indicadores geoquímicos de paleoproductividad y condiciones redox junto con foraminíferos bentónicos en los depósitos de plataforma del Oxfordiense (Jurásico superior) del Prebético Externo (Cordillera Bética, SE España) permite reconocer dos ciclos caracterizados por un incremento inicial de la productividad y una disminución de la oxigenación en el fondo y una posterior disminución en productividad y aumento de la oxigenación. Las condiciones disóxicas coinciden con máximos en la productividad marina superficial sugiriendo que la disminución de la oxigenación pudo estar relacionada con un mayor consumo relacionado con la oxidación de la materia orgánica más que por una circulación restringida. El límite entre ambos ciclos se caracteriza por valores bajos de elementos indicadores de condiciones reductoras, carbono orgánico total y las relaciones Sr/Al, P/Ti, Ca/Al y Ba/Al, indicando buena oxigenación del fondo marino, baja productividad y baja acumulación de materia orgánica. Los indicadores geoquímicos han mostrado ser una valiosa herramienta para interpretar fluctuaciones estratigráficas en las asociaciones de foraminíferos bentónicos, así como para evaluar la paleoecología de los principales géneros de foraminíferos. Spirillina es sensible a las disminuciones en el grado de oxigenación independientemente de la disponibilidad de alimento. Ophthalmidium presenta muy buena correspondencia con las fluctuaciones en paleoproductividad y toleró bajos niveles de oxigenación en la interfase agua-sedimento. Reophax fue un organismo oportunista que proliferó bajo condiciones adversas cuando la oxigenación o el alimento fueron factores limitantes. La variabilidad en la profundidad del microhabitat dentro del sedimento de Reophax favoreció su adaptación a condiciones adversas. Lenticulina muestra un comportamiento similar a Reophax. Finalmente, Ammobaculites muestra una escasa relación con las variaciones de los indicadores de paleoproductividad, pero se muestra intolerante con respecto a valores bajos de oxigenación en los microhábitats infaunales someros
Consumer-brand relationships under the marketing 3.0 paradigm: A literature review
Consumer-brand relationships encompass several dimensions, most of which have attracted growing research attention during the last years. Building these relationships is especially important in the marketing 3.0 era, where it is suggested that customers will choose those brands that satisfy their deepest needs. With these ideas in mind, this article provides a review of two key concepts implied in such relationships: brand love and customer engagement. Although both conceptions focus on different stages of consumer-brand relationships, they actually cover different perspectives on the same process. Moreover, they come from diverse conceptual paradigms: whilst brand love comes from the psychology discipline, engagement derives from diverse areas of the marketing field (e.g., the service-dominant logic perspective). However, their further empirical developments have taken place in marketing. Besides, both terms appear to be applied to different empirical perspectives: brand love is usually linked to the Fast Moving Consumer Goods industry and customer engagement to services
The Risk of Undeclared Allergens on Food Labels for Pediatric Patients in the European Union
The dietary avoidance of allergens has been widely recognized as the key intervention in the management of food allergies, but the presence of undeclared allergens makes compliance difficult. The aim of this study was to analyze the presence of undeclared allergens in food labeling through RASFF notifications in the European Union, focusing on those allergens that frequently affect the pediatric population and the implicated products, so as to provide useful information for its risk evaluation and the development of educational materials for patients. The results showed milk (20.5%), gluten (14.8%), and nuts (10.9%) to be the pediatric allergens with higher presences. In 80% of the notifications concerning milk and milk derivatives, the specific compound present (lactose or lactoprotein) was not identified. They were mainly present in cereal and bakery products, prepared dishes and snacks, and cacao and confectionery products, all of which are frequently consumed by the pediatric population. The large quantity (7.6%) of undeclared allergens in “free-from-allergen” products was also remarkable, especially in regard to the supposedly not-present allergens. Undeclared allergens in food products pose an evident risk for allergic patients and knowledge of them should take a relevant role in a patient’s nutritional education. It is also necessary to raise awareness among manufacturers and safety authorities. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
VNUML vs GNS3 en el desarrollo de laboratorios de redes virtuales
El aprendizaje práctico de redes de computadores
es reconocido como un proceso crítico que permite
a los estudiantes consolidar los conceptos introducidos
en las lecciones teóricas. En este sentido, las
tecnologías de virtualización están adquiriendo gran
relevancia debido a que permiten desarrollar laboratorios
de redes de computadores con un reducido
coste de despliegue y gestión. Este artículo presenta
un análisis comparativo entre GNS3 y VNUML, que
son herramientas de virtualización open-source que
han sido empleadas para el desarrollo de laboratorios
de red virtuales para llevar a cabo el proceso de
enseñanza-aprendizaje en las asignaturas Arquitectura
de Redes y Arquitectura de Redes Avanzadas
del Grado en Ingeniería Informática impartido en la
Universidad de Murcia. El estudio presenta las principales
ventajas y/o deficiencias de cada herramienta
tanto para profesores como alumnos y se identifican
los escenarios en los que parece más adecuada su
utilización.SUMMARY -- The practical learning of computer networks is
known to be a critical process in order to allow
students to consolidate the concepts introduced in
theoretical lessons. In this sense, virtualization technologies
are becoming popular since they allow
to set up a computer network laboratory with a reduced
deployment and management cost. This paper
presents a comparative analysis performed between
GNS3 and VNUML, which are open-source
tools for virtualization that have been used for developing
virtual network laboratories that support the
teaching-learning process in the Networks Architecture
and Advanced Networks Architecture subjects
of the Computer Engineering degree at the University
of Murcia. The study presents the main advantages
and/or deficiencies of each tool not only for professors
but also for students and identifies the scenarios
where the use of each tool seems to be more
appropriate.Peer Reviewe
Evolución y simbiosis de las propensiones esenciales en el escenario de la enseñanza de las ciencias experimentales
The main prospects on science teaching are analyzed. The recent paradiglns in computer technology have enabled the development of a second generation of instructional design. Additionally, breakthroughs in neuroscience provide a new focus to ecology in the field of science teaching in the general scenario defined by the theory of evolution. The authors have the conviction that the time has arrived for a new curriculum in sciences based on a symbiosis between computer technology, instructional design and neurobiology. As a consequence, curricular projects in sciences must be especially centered upon neuronal education. Finally, the incidence cif the science of complexity and the concept edge of chaos in education is considered
Trabajos de Prehistoria: su trayectoria como revista de impacto internacional
[ES] En 2008 Trabajos de Prehistoria entró en las bases de datos internacionales del SSCI, A&HCI y Scopus siendo la primera revista española del área de Arqueología con factor de impacto JCR. En el trabajo se muestra cómo este proceso de internacionalización es consecuencia de diferentes iniciativas de política científica del estado a nivel nacional y del propio CSIC. Se analiza la trayectoria de la revista desde su creación y se valora el impacto de esta internacionalización en su gestión reciente. Cabe destacar el papel[EN] Trabajos de Prehistoria was included in 2008 in the SSCI, A&HCI and Scopus international scientific databases. It was the first Spanish archaeological journal with a JCR impact factor. This paper shows how several initiatives in scientific policy by the National Spanish Government and the CSIC lead to international recognition. This study also shows the trajectory of the journal since its creation and evaluates the effects of the internationalisation on the current management. The role played by the reviewers has been fundamental in attaining and maintaining the journal’s high scientific quality.Peer reviewe
Experiencia con la herramienta de virtualización VNUML para la enseñanza de redes de computadores
La virtualización permite disponer y configurar infraestructuras de red con un coste asumible para un laboratorio y, a diferencia de los simuladores, muestra un comportamiento real del sistema. Este
artículo presenta la metodología que seguimos en la asignatura de Redes de la Facultad de Informática de la Universidad de Murcia para la enseñanza práctica de conceptos tales como encaminamiento,
movilidad IP, balanceo de carga y alta disponibilidad por medio de la herramienta de virtualización de código abierto VNUML. Para mostrar estos conceptos hemos añadido diversas utilidades al sistema de ficheros utilizado en VNUML. Gracias a estas herramientas, los alumnos han podido mejorar
el aprendizaje de estos conceptos como lo refutan las encuestas realizadas.Peer Reviewe
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