6,504 research outputs found
The challenge of detecting intracluster filaments with Faraday Rotation
The detection of filaments in the cosmic web will be crucial to distinguish
between the possible magnetogenesis scenarios and future large polarization
surveys will be able to shed light on their magnetization level. In this work,
we use numerical simulations of galaxy clusters to investigate their possible
detection. We compute the Faraday Rotation signal in intracluster filaments and
compare it to its surrounding environment. We find that the expected big
improvement in sensitivity with the SKA-MID will in principle allow the
detection of a large fraction of filaments surrounding galaxy clusters.
However, the contamination of the intrinsic Faraday Rotation of background
polarized sources will represent a big limiter to the number of objects that
can be significantly detected. We discuss possible strategies to minimize this
effect and increase the chances of detection of the cosmic web with the large
statistics expected from future surveys.Comment: 16 pages, accepted to Galaxie
Refrigeration Capacity and Effect of Ageing on the Operation of Cellulose Evaporative Cooling Pads, by Wind Tunnel Analysis
This study investigates the temperature reduction capacity and water consumption of a
fan-pad system installed in a greenhouse located in the coastal regions of AlmerÃa. The suitability
of this system for coastal zones with high environmental humidity during the summer is analyzed.
Historical temperature and relative humidity series are studied, obtaining the thermal difference and
maximum, medium, and minimum monthly water consumption of the pads based on the operation
data of the pads. Despite the high relative humidity of the air in the hottest hours of the day, a
decrease of 5.92 ºC in the mean temperature and a water consumption of 13.55 l/h per square meter
of an evaporative cooling pad are obtained in the month of August. Additionally, the operation of a
cellulose evaporative cooling pad installed for 3 years in a greenhouse is analyzed in a wind tunnel
and compared with that of a new pad of the same model. Over time and with low maintenance,
the porosity of the pad decreases due to salt incrustation. The salt incrustation makes airflow more
difficult in the pad, increasing the pressure drop by 170.04%; however, the air saturation efficiency of
the pad increases by 6.6% due to the greater contact time between the air and the waterMinisterio de EconomÃa y Competitividad de España AGL2015-68050-RUnión Europea (FEDER) AGL2015-68050-
Assessment of the cooling potential of an indoor living wall using different substrates in a warm climate
The use of vertical greenery systems in buildings is becoming very popular as they provide several benefits. In this work, the influence of an indoor living wall on the temperature and humidity in a hall inside the School of Agricultural Engineering (University of Seville) was studied. Four different substrates, Geotextile, Epiweb, Xaxim and coconut fibre, were used to grow the plants in order to assess their performance. Several parameters such as temperature, humidity, plant growth or water consumption were monitored and analyzed during a 4-month period. The cooling effect of the living wall was proven, with an average reduction of 4°C over the room temperature though maximum decrements of 6°C have been observed in warmer conditions. Higher air humidity levels were experienced near the living wall, increasing the overall humidity in the room. All the substrates tested were suitable for plant growing and their behaviour was similar. Geotextile showed the best cooling capacity but higher water consumption, coconut fibre presented degradation problems and Epiweb performance was the poorest. Therefore, these systems have been proven to be very useful and interesting for warm indoor environments due to the cooling effect observed in addition to their bio-filtration capacity and the aesthetic component
Dynamical evolution of magnetic fields in the intracluster medium
We investigate the evolution of magnetic fields in galaxy clusters starting
from constant primordial fields using highly resolved ()
cosmological MHD simulations. The magnetic fields in our sample exhibit
amplification via a small-scale dynamo and compression during structure
formation. In particular, we study how the spectral properties of magnetic
fields are affected by mergers, and we relate the measured magnetic energy
spectra to the dynamical evolution of the intracluster medium. The magnetic
energy grows by a factor of 40-50 in a time-span of Gyr and
equipartition between kinetic and magnetic energy occurs on a range of scales
( at all epochs) depending on the turbulence state of the
system. We also find that, in general, the outer scale of the magnetic field
and the MHD scale are not simply correlated in time. The effect of major
mergers is to shift the peak magnetic spectra to it smaller scales, whereas the
magnetic amplification only starts after 1 Gyr. In contrast,
continuous minor mergers promote the steady growth of the magnetic field. We
discuss the implications of these findings in the interpretation of future
radio observations of galaxy clusters.Comment: Accepted in MNRAS; 16 pages, 34 figure
On Rules and Parameter Free Systems in Bounded Arithmetic
We present model–theoretic techniques to obtain conservation
results for first order bounded arithmetic theories, based on a hierarchical
version of the well known notion of an existentially closed model.Ministerio de Educación y Ciencia MTM2005-0865
Existentially Closed Models and Conservation Results in Bounded Arithmetic
We develop model-theoretic techniques to obtain conservation results for first order Bounded Arithmetic theories, based on a hierarchical version of the well-known notion of an existentially closed model. We focus on the classical Buss' theories Si2 and Ti2 and prove that they are ∀Σbi conservative over their inference rule counterparts, and ∃∀Σbi conservative over their parameter-free versions. A similar analysis of the Σbi-replacement scheme is also developed. The proof method is essentially the same for all the schemes we deal with and shows that these conservation results between schemes and inference rules do not depend on the specific combinatorial or arithmetical content of those schemes. We show that similar conservation results can be derived, in a very general setting, for every scheme enjoying some syntactical (or logical) properties common to both the induction and replacement schemes. Hence, previous conservation results for induction and replacement can be also obtained as corollaries of these more general results.Ministerio de Educación y Ciencia MTM2005-08658Junta de AndalucÃa TIC-13
Enfermedad de Parkinson y musicoterapia
La enfermedad de Parkinson es la segunda enfermedad neurodegenerativa en España
producida por una alteración de la sustancia negra del cerebro. Esta afectación da lugar
a un déficit de dopamina, causante de la sintomatologÃa de esta enfermedad.
Tanto los sÃntomas motores como los no motores pueden ser tratados mediante un
tratamiento farmacológico, logopédico, psicológico y con rehabilitación fÃsica, o
mediante terapias novedosas como es el caso de la Musicoterapia.
El objetivo es mostrar la importancia de intervenciones como la musicoterapia en el
tratamiento de la enfermedad de Parkinson.
Para lograr dicho objetivo se ha llevado a cabo una búsqueda bibliográfica a través de la
cual se ha obtenido información sobre la enfermedad: clÃnica, etiologÃa, tratamiento, etc
y sobre lo que es la musicoterapia y cómo actúa sobre todas las esferas del ser humano.
La música contribuye en gran medida en la mejora de los sÃntomas motores de la
enfermedad de Parkinson, pero también logra que las personas que padecen la
enfermedad se sientan mejor, permitiendo que se relacionen con otras personas, lo que
supone una mejorÃa de su calidad de vidaOtroGrado en EnfermerÃ
Enhancing cognition before clinical symptoms of dementia.
As the title of the special issue indicates, controversy surrounds augmentation of brain cognition in humans. Lacking efficacious drugs for Alzheimer's disease (AD) and with many AD patients recruited for clinical trials that unfortunately do not provide the expected results, one wonders whether to test cognition enhancement strategies in individuals without symptoms of cognition decline. This opinion article presents the view that safe drugs and or dietary supplements should be tested worldwide in aged individuals under the control of a non-for-profit organization
On the quantifier complexity of Δ n+1 (T)– induction
In this paper we continue the study of the theories IΔ n+1 (T), initiated in [7]. We focus on the quantifier complexity of these fragments and theirs (non)finite axiomatization. A characterization is obtained for the class of theories such that IΔ n+1 (T) is Πn+2 –axiomatizable. In particular, IΔ n+1 (IΔ n+1 ) gives an axiomatization of Th Πn+2 (IΔ n+1 ) and is not finitely axiomatizable. This fact relates the fragment IΔ n+1 (IΔ n+1 ) to induction rule for Δ n+1 –formulas. Our arguments, involving a construction due to R. Kaye (see [9]), provide proofs of Parsons’ conservativeness theorem (see [16]) and (a weak version) of a result of L.D. Beklemishev on unnested applications of induction rules for Πn+2 and Δ n+1 formulas (see [2]).Ministerio de Educación y Cultura DGES PB96-134
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