647 research outputs found
Narcissus dubius, Narcisse Douteux
This species is endemic to southern France and eastern Spain. It is assessed as Least Concern because it has a widespread distribution, occurs in several protected areas throughout its range and its population is not expected to significantly decline in the near future. Further studies on the genetic structure of its population and trends in population size at global level are needed
Dynamic phase transition properties and hysteretic behavior of a ferrimagnetic core-shell nanoparticle in the presence of a time dependent magnetic field
We have presented dynamic phase transition features and stationary-state
behavior of a ferrimagnetic small nanoparticle system with a core-shell
structure. By means of detailed Monte Carlo simulations, a complete picture of
the phase diagrams and magnetization profiles have been presented and the
conditions for the occurrence of a compensation point in the system
have been investigated. According to N\'{e}el nomenclature, the magnetization
curves of the particle have been found to obey P-type, N-type and Q-type
classification schemes under certain conditions. Much effort has been devoted
to investigation of hysteretic response of the particle and we observed the
existence of triple hysteresis loop behavior which originates from the
existence of a weak ferromagnetic core coupling , as well as a
strong antiferromagnetic interface exchange interaction . Most
of the calculations have been performed for a particle in the presence of
oscillating fields of very high frequencies and high amplitudes in comparison
with exchange interactions which resembles a magnetic system under the
influence of ultrafast switching fields. Particular attention has also been
paid on the influence of the particle size on the thermal and magnetic
properties, as well as magnetic features such as coercivity, remanence and
compensation temperature of the particle. We have found that in the presence of
ultrafast switching fields, the particle may exhibit a dynamic phase transition
from paramagnetic to a dynamically ordered phase with increasing ferromagnetic
shell thickness.Comment: 12 pages, 12 figure
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Role and task recommendation and social tagging to enable social business process management
Traditional Business Process Management (BPM) poses a number of limitations for the management of ad-hoc processes, where the execution paths are not designed a priori and evolve during enactment. Social BPM, which predicates to integrate social software into the BPM lifecycle, has emerged as an answer to such limitations. This paper presents a framework for social BPM in which social tagging is used to capture process knowledge emerging during the enactment and design of the processes. Process knowledge concerns both the type of activities chosen to fulfil a certain goal and the skills and experience of users in executing specific tasks. Such knowledge is exploited by recommendation tools to support the design and enactment of future process instances. We first provide an overview of our framework, introducing the concepts of role and task recommendations, which are supported by social tagging. These mechanisms are then elaborated further by an example. Eventually, we discuss a prototype of our framework enabling collaborative process design and execution
Dynamic phase transition of the Blume-Capel model in an oscillating magnetic field
We employ numerical simulations and finite-size scaling techniques to
investigate the properties of the dynamic phase transition that is encountered
in the Blume-Capel model subjected to a periodically oscillating magnetic
field. We mainly focus on the study of the two-dimensional system for various
values of the crystal-field coupling in the second-order transition regime. Our
results indicate that the present non-equilibrium phase transition belongs to
the universality class of the equilibrium Ising model and allow us to construct
a dynamic phase diagram, in analogy to the equilibrium case, at least for the
range of parameters considered. Finally, we present some complementary results
for the three-dimensional model, where again the obtained estimates for the
critical exponents fall into the universality class of the corresponding
three-dimensional equilibrium Ising ferromagnet.Comment: 27 pages, 1 table, 15 figures, minor corrections (updated figures 3
and 4
Beta-hemolytic Streptococcus dysgalactiae strains isolated from horses are a genetically distinct population within the Streptococcus dysgalactiae taxon
The pathogenic role of beta-hemolytic Streptococcus dysgalactiae in the equine
host is increasingly recognized. A collection of 108 Lancefield group C (n =
96) or L (n = 12) horse isolates recovered in the United States and in three
European countries presented multilocus sequence typing (MLST) alleles,
sequence types and emm types (only 56% of the isolates could be emm typed)
that were, with few exceptions, distinct from those previously found in human
Streptococcus dysgalactiae subsp. equisimilis. Characterization of a subset of
horse isolates by multilocus sequence analysis (MLSA) and 16S rRNA gene
sequence showed that most equine isolates could also be differentiated from S.
dysgalactiae strains from other animal species, supporting the existence of a
horse specific genomovar. Draft genome information confirms the
distinctiveness of the horse genomovar and indicates the presence of
potentially horse-specific virulence factors. While this genomovar represents
most of the isolates recovered from horses, a smaller MLST and MLSA defined
sub-population seems to be able to cause infections in horses, other animals
and humans, indicating that transmission between hosts of strains belonging to
this group may occur
Experimental characterization and performance evaluation of geothermal grouting materials subjected to heating–cooling cycles
In recent years, the increasing rise in environmental awareness among energy consumers has led to an increasing use of renewable energies such as the geothermal energy. An important role in the efficient exploitation of the geothermal resource is played by the grouting material placed in the borehole between the pipes and the ground. Actually, the use of proper grouts is essential to provide an effective heat transfer between the ground and the heat carrier fluid in the pipes, and also to comply with the mechanical and environmental demands. However, when it comes to the construction of the GHP installations, the grout is especially required to be easy to work with (workable) and for this reason more water than required is sometimes added. In order to assess the suitability of grouting materials with significant water/solid ratios, the thermal conductivity, mechanical strength and permeability of five different grouts and grout–pipe specimens were measured for their laboratory characterization. In addition, the grouts were subjected to heating and cooling cycles to evaluate their durability with time in terms of the potential degradation of the materials and the loss of quality of the grout–pipe interface. According to the results obtained, the grouts here tested are appropriate for most of the geothermal heat pump installations, especially for those with low to medium ground thermal properties.The authors wish to express their gratitude to the Ministerio de Economía y Competitividad which funded this study within the Spanish National Plan for Scientific and Technical Research and Innovation (INNPACTO program) through the research project IPT-2011-0877-920000
A survey of localization in wireless sensor network
Localization is one of the key techniques in wireless sensor network. The location estimation methods can be classified into target/source localization and node self-localization. In target localization, we mainly introduce the energy-based method. Then we investigate the node self-localization methods. Since the widespread adoption of the wireless sensor network, the localization methods are different in various applications. And there are several challenges in some special scenarios. In this paper, we present a comprehensive survey of these challenges: localization in non-line-of-sight, node selection criteria for localization in energy-constrained network, scheduling the sensor node to optimize the tradeoff between localization performance and energy consumption, cooperative node localization, and localization algorithm in heterogeneous network. Finally, we introduce the evaluation criteria for localization in wireless sensor network
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