6,023 research outputs found
Supercritical super-Brownian motion with a general branching mechanism and travelling waves
We consider the classical problem of existence, uniqueness and asymptotics of
monotone solutions to the travelling wave equation associated to the parabolic
semi-group equation of a super-Brownian motion with a general branching
mechanism. Whilst we are strongly guided by the probabilistic reasoning of
Kyprianou (2004) for branching Brownian motion, the current paper offers a
number of new insights. Our analysis incorporates the role of Seneta-Heyde
norming which, in the current setting, draws on classical work of Grey (1974).
We give a pathwise explanation of Evans' immortal particle picture (the spine
decomposition) which uses the Dynkin-Kuznetsov N-measure as a key ingredient.
Moreover, in the spirit of Neveu's stopping lines we make repeated use of
Dynkin's exit measures. Additional complications arise from the general nature
of the branching mechanism. As a consequence of the analysis we also offer an
exact X(log X)^2 moment dichotomy for the almost sure convergence of the
so-called derivative martingale at its critical parameter to a non-trivial
limit. This differs to the case of branching Brownian motion and branching
random walk where a moment `gap' appears in the necessary and sufficient
conditions.Comment: 34 page
Using Statistical Analysis to Improve Data Partitioning in Algorithms for Data Parallel Processing Implementation
In multiprocessor systems, data parallelism is the execution of the same task on data distributed across multiple processors. It involves splitting the data set into smaller data partitions or batches. The process to split the data among the different processors is call “Data Partitioning” and it is an important factor of efficiency for data parallel processing implementation. Data partitioning influences the workload in each processing unit and the network traffic between processes. A poor partition quality can lead to serious performance problems. This research presents a data partitioning method that can be used to improve the performance of data parallel implementations. The proposed method relies on using an initial screening experiment to run a portion of data units. Regression is then used to create a prediction model of the processing times for each data unit. Using the estimated processing time, load balancing is achieved by implementing a greedy algorithm to distribute the units in a parallel environment. Discrete event simulation is used as the application of this research. Comparisons between equal data partitioning and the methodology proposed in this research indicate that time savings and equal load balancing can be achieved
Enriched elderly virtual profiles by means of a multidimensional integrated assessment platform
The pressure over Healthcare systems is increasing in most developed countries. The generalized aging of the population is one of the main causes. This situation is even worse in underdeveloped, sparsely populated regions like Extremadura in Spain or Alentejo in Portugal. The authors propose to use the Situational-Context, a technique to seamlessly adapt Internet of Things systems to the needs and preferences of their users, for virtually modeling the elderly. These models could be used to enhance the elderly experience when using those kind of systems without raising the need for technical skills or the costs of implementing such systems by the regional healthcare systems. In this paper, the integration of a multidimensional integrated assessment platform with such virtual profiles is presented. The assessment platform provides and additional source of information for the virtual profiles that is used to better adapt existing systems to the elders needs
Disentangling the jet emission from protostellar systems. The ALMA view of VLA1623
Context: High-resolution studies of class 0 protostars represent the key to
constraining protostar formation models. VLA16234-2417 represents the prototype
of class 0 protostars, and it has been recently identified as a triple
non-coeval system. Aim: We aim at deriving the physical properties of the jets
in VLA16234-2417 using tracers of shocked gas. Methods: ALMA Cycle 0 Early
Science observations of CO(2-1) in the extended configuration are presented in
comparison with previous SMA CO(3-2) and Herschel-PACS [OI}] 63 micron
observations. Gas morphology and kinematics were analysed to constrain the
physical structure and origin of the protostellar outflows. Results: We reveal
a collimated jet component associated with the [OI] 63 micron emission at about
8'' (about 960 AU) from source B. This newly detected jet component is
inversely oriented with respect to the large-scale outflow driven by source A,
and it is aligned with compact and fast jet emission very close to source B
(about 0.3'') rather than with the direction perpendicular to the A disk. We
also detect a cavity-like structure at low projected velocities, which
surrounds the [OI] 63 micron emission and is possibly associated with the
outflow driven by source A. Finally, no compact outflow emission is associated
with source W. Conclusions: Our high-resolution ALMA observations seem to
suggest there is a fast and collimated jet component associated with source B.
This scenario would confirm that source B is younger than A, that it is in a
very early stage of evolution, and that it drives a faster, more collimated,
and more compact jet with respect to the large-scale slower outflow driven by
A. However, a different scenario of a precessing jet driven by A cannot be
firmly excluded from the present observations.Comment: Accepted for publication in Astronomy & Astrophysic
The prolific backbone for supercritical superdiffusions
We develop an idea of Evans and O'Connell, Englander and Pinsky and Duquesne
and Winkel by giving a pathwise construction of the so called `backbone'
decomposition for supercritical superprocesses. Our results also complement a
related result for critical -superprocesses given in Etheridge and
Williams \cite{EW}. Our approach takes an analytical point of view which is
more in the spirit of the original Evans and O'Connell paper
APPLICATION OF ESSENTIAL OILS FROM TWO SPECIES OF THE RUTACEAE FAMILY AS CELLULAR OXIDATION CONTROLLER AGENT AND TRYPANOCIDAL CAPACITY
AbstractThe essential oil isolated by hydrodistillation from peel of Citrus aurantium and Swinglea glutinosa, collected from Ibagué-Province of Tolima-Colombia (South America), was analyzed by GC/MS. The major compounds identified in essential oil of S. glutinosa were germacrene-D (30.8%), β-pinene (22.6%) and sabinene (11.6%), while limonene (94.4%)was identified as the most abundant component in C. aurantium.The ability of these products and mixturesto control cellular oxidation and measure theiranti-epimastigotes of Trypanosoma cruzi activity, the protozoan Chagas transmitter,were investigated.Besides, the type ofdrug interactionbetweenessential oil mixtureswas determinedby the values ofcombination index, which indicated for all cases the existence of a strong antagonism between the mixtures prepared.According to ABTS assay, β-carotene bleaching test andprotective activityagainst erythrocytes degradationshowed that volatiles compounds have a wide spectrum as cellular oxidation controller.This is the first time, that oils of S. glutinosa and C. aurantium, have high activity against T. cruzi, in vitro; capacity that could be directly associated to the chemotype of they, one of which (Swinglea glutinosa) appears not to be found in other research.  KeywordsEssential oil composition, Citrusaurantium, Swingleaglutinosa, ABTS, Rutaceae.Â
Investigación minera por estaño en la reserva nº 146 "Villardeciervos" (Orense)
[Resumen] La presente comunicación concierne a los trabajos realizados y resultados obtenidos en la investigación llevada a cabo por ENADIMSA, en la Reserva a favor del Estado na 146, "Villardeciervos". Se investigaron tres zonas de interés potencial que habían sido puestas de manifiesto en trabajos anteriores realizados por el IGME, reflejados en el infonne "Estimación del potencial minero en la zona de Villardevós-(Orense)" (1970). Los resultados fueron considerados negativos en lo que a interés minero se refiere[Abstract] This paper deals with the work and results obtained during the investigation, carried out by ENADIMSA, at "Villadeciervos" state reservation, na 146. Three potentially interesting areas, previously evidenced by studies conducted by the "IGME", which are described in the report: "Estimación del potencial minero en la zona de Villardevós-(Orense)" (1976), were investigated. With respect to mineral potential the results obtamded were considered to be negativ
EU Cohesion policy 2007-13 and the implications for Spain : who gets what, when and how?
The recent negotiation of the EU budget and the associated reform of EU Cohesion policy have had major policy implications for Spain, the country in receipt of most Cohesion policy support in the current programming period (2000-06). EU enlargement, combined with relatively rapid growth in Spain, impacted on the eligibility of Spanish regions for Cohesion support while also taking the country as a whole beyond the eligibility threshold for the Cohesion Fund. As a result, based on the original Commission budget proposals of February 2004, Spain was facing a reduced Cohesion policy budget of at least a half (to below €30 billion). This paper first reviews the budget negotiations from a Spanish (Cohesion policy) perspective, identifying the key negotiating goals and the extent to which they were achieved. It then looks at the outcome of the negotiations for Spain, initially at the national level and then in the regions. It highlights the significant differential impacts of the cutbacks in Cohesion policy allocations at the regional level and the pressures on the Spanish government to modulate the regional impact of the budgetary changes. Having considered the direct funding implications of the new Cohesion policy, the second half of the paper is concerned with the regulatory, institutional and economic impacts of the new policy regime. Many of the reform proposals fit with Spanish priorities, not least the new rationale for Cohesion policy (with its stress on the Lisbon and Gothenburg agendas) and the new policy architecture (with all regions eligible for some form of support and with a related shift from a geographic to more of a thematic focus). The retention of the key Structural Funds principles has also been welcomed in Spain, unsurprising given the wealth of experience and expertise built up over three (high-spending) programming cycles. As in most Member States, the main regulatory concern relates to the extent to which a more simplified and devolved approach to Funds' implementation will be achieved in practice. As regards policy and institutional impacts, the paper brings together regional views on the new budgetary and regulatory frameworks and reviews how the new regulations are being implemented in practice. A discussion of the developing National Strategic Reference Framework and the related Operational Programmes makes clear that the strong emphasis on the Lisbon agenda is not viewed as a constraint in Spain; rather, it is felt to fit well with recent Spanish developments and goals. Finally, the paper considers the economic implications of the reductions in Cohesion policy support. On the basis of evaluation studies, it highlights the positive impact the Funds have had in the past and the potentially quite varied regional impacts the reductions in funding may have in the future
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