2,143 research outputs found
Cosmological solutions in F(R) Horava-Lifshitz gravity
At the present work, it is studied the extension of F (R) gravities to the
new recently proposed theory of gravity, the so-called Horava-Lifshitz gravity,
which provides a way to make the theory power counting renormalizable by
breaking Lorentz invariance. It is showed that dark energy can be well
explained in the frame of this extension, just in terms of gravity. It is also
explored the possibility to unify inflation and late-time acceleration under
the same mechanism, providing a natural explanation the accelerated expansion.Comment: 4 pages. Contribution to the Proceedings of the Spanish Relativity
Meeting (ERE) 2010, Granada, Spai
Testing the equation of state for viscous dark energy
Some cosmological scenarios with bulk viscosity for the dark energy fluid are considered. Based on
some considerations related to hydrodynamics, two different equations of state for dark energy are
assumed, leading to power-law and logarithmic effective corrections to the pressure. The models are tested
with the latest astronomical data from type Ia supernovae (Pantheon sample), measurements of the Hubble
parameter HðzÞ, baryon acoustic oscillations and cosmic microwave background radiation. In comparison
with the ΛCDM model, some different results are obtained and their viability is discussed. The power-law
model shows some modest results, achieved under negative values of bulk viscosity, while the logarithmic
scenario provide good fits in comparison to the ΛCDM model.Ministerio de EconomÃa, Industria y Competitividad (project FIS2016-76363-P)Agencia de Gestión de Ayudas Universitarias y de Investigación (project 2017 SGR 247)CANTATA COST action (grant CA15117
Ekpyrotic universes in Ho\v{r}ava-Lifshitz gravity
The Ekpyrotic scenario is studied in the context of some extensions of
Ho\v{r}ava-Lifshitz gravity. Some particular solutions that lead to cyclic
Hubble parameters are analyzed, where the corresponding gravitational actions
are reconstructed by using several techniques and auxiliary fields. Its
comparison with standard gravity is performed. In addition, the
so-called Little Rip, a stage of the universe evolution when some bounded
systems may be dissolute, is also studied in this frame of theories.Comment: 12 pages. Version to be published in PR
An Integrated Framework for Multiprocessor, Multimoded Real-Time Applications
The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-30598-6_2In this paper we propose an approach for building real-time systems under a combination of requirements: specification and handling of operating modes and mode changes; implementation on top of a multiprocessor platform; integration of both aspects within a common framework; and connection with schedulability analysis procedures.
The proposed approach uses finite state machines to describe operating modes and transitions, and a framework of real-time utilities that implements the required behaviour in Ada 2012. Automatic code generation plays an important role: the system is derived from the functional and timing specification, and implemented according to the abstractions provided by the framework. Response time analysis enables assessing the schedulability of the different operating modes and the transitions between modes.This work was partially supported by the Vicerrectorado de Investigación of the
UPV (PAID-06-10-2397), Ministerio de Ciencia e Innovación (TIN2011-28567-C03-
03) and European Union (FP7-ICT-287702)Sáez Barona, S.; Real Sáez, JV.; Crespo, A. (2012). An Integrated Framework for Multiprocessor, Multimoded Real-Time Applications. En Reliable Software Technologies – Ada-Europe 2012. Springer. 18-34. https://doi.org/10.1007/978-3-642-30598-6_21834Wellings, A.J., Burns, A.: A Framework for Real-Time Utilities for Ada 2005. Ada Letters XXVII(2) (August 2007)Real, J., Crespo, A.: Incorporating Operating Modes to an Ada Real-Time Framework. Ada Letters 30(1) (April 2010)Sáez, S., Terrasa, S., Crespo, A.: A Real-Time Framework for Multiprocessor Platforms Using Ada 2012. In: Romanovsky, A., Vardanega, T. (eds.) Ada-Europe 2011. LNCS, vol. 6652, pp. 46–60. Springer, Heidelberg (2011)Joseph, M., Pandya, P.: Finding response times in a real-time system. British Computer Society Computer Journal 29(5), 390–395 (1986)Audsley, N., Burns, A., Richardson, M., Tindell, K., Wellings, A.J.: Applying new scheduling theory to static priority pre-emptive scheduling. Software Engineering Journal 8(5), 284–292 (1993)Real, J., Crespo, A.: Mode Change Protocols for Real-Time Systems: A Survey and a new Proposal. Real-Time Systems 26(2), 161–197 (2004)Harel, D.: Statecharts: A visual formalism for complex systems. The Science of Computer Programming 8(3), 231–274 (1987)Object Management Group: Unified Modeling Language (OMG UML) V2.4 (August 2011), http://www.omg.org/spec/UML/2.4.1Sáez, S., Terrasa, S., Lorente, V., Crespo, A.: Implementing Reactive Systems with UML State Machines and Ada 2005. In: Kordon, F., Kermarrec, Y. (eds.) Ada-Europe 2009. LNCS, vol. 5570, pp. 149–163. Springer, Heidelberg (2009)Burns, A., Wellings, A.J.: Dispatching Domains for Multiprocessor Platforms and their Representation in Ada. In: Real, J., Vardanega, T. (eds.) Ada-Europe 2010. LNCS, vol. 6106, pp. 41–53. Springer, Heidelberg (2010)Barnett, J.: State Chart XML (SCXML): State Machine Notation for Control Abstraction (May 2008), http://www.w3.org/TR/scxml
Entomological fauna associated with Aguaribay : Mendoza (Argentina)
En los relevamientos de especias dañinas
y benéficas presentes en el aguaribay
(Schinus molle L. var. Areira), para inventariar
su entomofauna se efectuaron observaciones
en distintas zonas de Mendoza (Argentina)
en 1988/91 y 1994/96, confirmando
y actualizando la bibliografÃa.
Se recolectó material a campo para su
identificación sistemática. Se evaluaron daños
y se los documentó fotográficamente. En
el laboratorio se conservaron muestras con
parasitoides hasta la aparición de adultos
para su clasificación, registrándose 8 especies
de Homoptera, 7 de Hymenoptera, 7 de
Coleoptera, 5 de Lepidoptera, 4 de Diptera,
4 de Thysanoptera, 2 de Hemiptera y 2 de
Neuroptera.
Las principales especies que afectan al
Aguaribay son Calophya sp. (Homoptera -
Psyllidae), Ceroplastes grandis (Homoptera
- Coccidae) y Aphis schinifoliae (Homoptera
- Aphididae). También cuenta con una importante
fauna benéfica: coccinélidos,
parasitoides, sÃrfidos y crisópidos.Pest and beneficial species present in
Schinus molle L. var. Areira were monitoring
in order to obtain an inventory of its entomological
fauna. It was made observations in
different zones of Mendoza from 1988 to 1991,
and then, between 1994 and 1996, it was
confirmed further observations and it was
brought up to day bibliographical revisions. It
was collected material in field in order to made
its systematic identification. Damages were
evaluated and documented photographically.
Samples with parasitoids were stored in
laboratory until the appearance of adults for
their classification. It was registered: 8 species of
Homoptera, 7 of Hymenoptera, 7 of Coleop-tera,
5 of Lepidoptera, 4 of Diptera, 4 of Thysanoptera,
2 of Hemiptera and 2 of Neuroptera.
The main pest are: Calophya sp.
(Homoptera - Psyllidae), Ceroplastes grandis
(Homoptera - Coccidae) and Aphis schinifoliae
(Homoptera - Aphididade). Also, there is an
important beneficial fauna: Coccinellidae,
parasitoids, Syrphidae and Chrysopidae.Fil: Sáez, César C..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: Mácola, Guido S..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: Holgado, Miriam G..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: GarcÃa Sáez, José G..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias Biológica
Thrips : population dynamics of Thrips tabaci Lind. in garlic (Mendoza, Argentina)
En el presente trabajo se da a conocer
la dinámica poblacional de Thrips tabaci
(trips del ajo y la cebolla) en cultivos de ajos
colorados del departamento de Luján de
Cuyo, provincia de Mendoza, verificándose
que el máximo pico poblacional expresado
en números de individuos por plantas se alcanza en noviembre, con un ascenso rápido que comienza en octubre y un decrecimiento de igual caracterÃstica en diciembre, en coincidencia con la finalización del ciclo fenológico del cultivo.The actual work give to know the
population dynamic of the Trhips tabaci
(onions and garlic thrips) in cultivation of “red
onions“ in the departament Luján de Cuyo,
of the province of Mendoza, preve that the
maximum populatin peak expresed in
number of individuals per plants is reached
in november, with a fast ascension in october
and degression of equal characteristcs in
december, in coincidence with the end of
phenologyc cicle of the cultivation.Fil: GarcÃa Sáez, José G..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: Mácola, Guido S..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias Biológica
Thin and thick cloud top height retrieval algorithm with the Infrared Camera and LIDAR of the JEM-EUSO Space Mission
The origin of cosmic rays have remained a mistery for more than a century.
JEM-EUSO is a pioneer space-based telescope that will be located at the
International Space Station (ISS) and its aim is to detect Ultra High Energy
Cosmic Rays (UHECR) and Extremely High Energy Cosmic Rays (EHECR) by observing
the atmosphere. Unlike ground-based telescopes, JEM-EUSO will observe from
upwards, and therefore, for a properly UHECR reconstruction under cloudy
conditions, a key element of JEM-EUSO is an Atmospheric Monitoring System
(AMS). This AMS consists of a space qualified bi-spectral Infrared Camera, that
will provide the cloud coverage and cloud top height in the JEM-EUSO Field of
View (FoV) and a LIDAR, that will measure the atmospheric optical depth in the
direction it has been shot. In this paper we will explain the effects of clouds
for the determination of the UHECR arrival direction. Moreover, since the cloud
top height retrieval is crucial to analyze the UHECR and EHECR events under
cloudy conditions, the retrieval algorithm that fulfills the technical
requierements of the Infrared Camera of JEM-EUSO to reconstruct the cloud top
height is presently reported.Comment: 5 pages, 6 figures, Atmohead Conference 201
A Complexity Architecture for Information Technologies: a Three-Year Didactic Experiment
One medium-term strategy for helping in the management of complexity is the introduction of a conceptual complexity component in the very centre of university curricula. In very few areas is the growth of complexity as evident as in the information technologies (ITs), the focus of the work presented in the current paper. We have therefore developed an integrated way of tackling the specific field of information technologies by means of an approach,to complexity. The content of this paper describes the guidelines of our research effort, placing an emphasis on informatics. Concepts of complexity based on the system metaphor have been substantially drawn upon in this exercise and are thus presented in some detail.
Also described is a didactic experiment conducted by the author and designed to provide a new and integrating approach to University curricula for future professionals. The students' "discovery" of complexity is the focal point of the experiment. The findings of this effort are encouraging and call for the continuation and expansion of this experiment
Strategies of management for the control of Thrips tabaci Lind. in red garlic
En cultivos de ajo colorado de Luján de
Cuyo (Mendoza, Argentina) realizados en
1996/97/98 se compararon tres alternativas
de manejo para el control del trips del ajo y
la cebolla:
a) control quÃmico en tiempos calendarios sin
considerar la dinámica poblacional, modalidad
del productor
b) control quÃmico teniendo en cuenta la dinámica
poblacional
c) sin tratamientos quÃmicos
Los resultados obtenidos no muestran
diferencias estadÃsticamente significativas en
los rendimientos del cultivo (p > 0,05) para
las condiciones del ensayo y no se recomienda
el empleo de tratamientos quÃmicos.In Red Garlic cultivation of Luján de
Cuyo (Mendoza, Argentina) carried out
during 1996/97/98, were compared three
alternatives of management for the control
of the onion and garlic Thrips.
a) chemical control according calendar
treatment proposed by productors
b) chemical control according with the
dynamical of the population
c) without chemical control
The results do not shown statistical
significant different in yields (p > 0,05) in the
field conditions of the essay, for this, we do
not recommend the use of chemical
treatment.Fil: GarcÃa Sáez, José G..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: Mácola, Guido S..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: Llera, JoaquÃn.
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Biomatemática y FisicoquÃmic
Vacuum type I spacetimes and aligned Papapetrou fields: symmetries
We analyze type I vacuum solutions admitting an isometry whose Killing
2--form is aligned with a principal bivector of the Weyl tensor, and we show
that these solutions belong to a family of type I metrics which admit a group
of isometries. We give a classification of this family and we study the
Bianchi type for each class. The classes compatible with an aligned Killing
2--form are also determined. The Szekeres-Brans theorem is extended to non
vacuum spacetimes with vanishing Cotton tensor.Comment: 19 pages; a reference adde
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