5,672 research outputs found
Search for charginos, neutralinos, and gravitinos at LEP
The hep-ex data base was decided not to be an appropriate place to make
DELPHI notes public. Sorry for the inconvenience.Comment: the paper should not have been made publi
Formulation of exactly balanced solvers for blood flow in elastic vessels and their application to collapsed states
In this work, numerical solvers based on extensions of the Roe and HLL schemes are adapted to deal with test cases involving extreme collapsing conditions in elastic vessels. To achieve this goal, the system is transformed to provide a conservation–law form, allowing to define Rankine–Hugoniot conditions. The approximate solvers allow to describe the inner states of the solution. Therefore, source term fixes can be used to prevent unphysical values of vessel area and, at the same time, the eigenvalues of the system control stability. Numerical solvers of different order are tested using a wide variety of Riemann problems, including extreme vessel collapse and blockage. In all cases, the robustness of the approximate solvers presented here is checked using first and third order methods in time and space, using the WENO reconstruction scheme in combination with the TVDRK3 method
Research on nonlinear and quantum optics at the photonics and quantum information group of the University of Valladolid
We outline the main research lines in Nonlinear and Quantum Optics of the Group of Photonics and Quantum Information at the University of Valladolid. These works focus on Optical Solitons, Quantum Information using Photonic Technologies and the development of new materials for Nonlinar Optics. The investigations on optical solitons cover both temporal solitons in dispersion managed fiber links and nonparaxial spatial solitons as described by the Nonlinear Helmholtz Equation. Within the Quantum Information research lines of the group, the studies address new photonic schemes for quantum computation and the multiplexing of quantum data. The investigations of the group are, to a large extent, based on intensive and parallel computations. Some associated numerical techniques for the development of the activities described are briefly sketched
La prĂłtesis de expansiĂłn de Giannini en el tratamiento del pie plano-laxo infantil
Presentamos una serie de 50 pies plano-laxo infantil intervenidos con la prĂłtesis
de expansión de Giannini entre los años 1989 y 1992. Para evaluar la corrección obtenida se ha
tenido en cuenta la morfologĂa y sintomatologĂa del pie, la valoraciĂłn del fotopodograma y el ángulo
de Moreau-Costa-Bartani y la lĂnea de Sheade o eje de Meary-Tomeno en el estudio radiográfico.
En la valoraciĂłn final de resultados constatamos 14 casos (28%) excelentes, 31 (62%) buenos,
2 (4%) regulares y 3 (6%) malos.The authors present their experience in the surgical treatment of 50 essencial valgus
fĂat feet, performed bctween 1989 and 1992, using Giannini's subtalar expansive prosthesis.
Pacients were assessed clinically, radiologically and by photopodography for the Moreau-CostaBartani
angle and the Sheade line or Meary-Tomeno axis. In the final evaluation 14 cases (28%)
were judged to achieved excellent results, 31 (62%) good results, 2 (4%) fair results and 3 (6%)
poor result
A POD-based reduced order model applied to 1D shallow water equations
Many environmental problems involving free surface flow can be solved using the shallow water equations (SWE) often involving high computational costs due to the large spatial and temporal scales of the events. In recent times, reduced order models (ROM) techniques are increasingly used to improve the computational efficiency of simulation models. The Proper Orthogonal Decomposition (POD) method provides an orthogonal basis for representing a given set of data and constructing the ROM by means of the method of snapshots. In this work, a POD-based intrusive ROM strategy is applied to the 1D SWE. The main goal of this work is to build a simulation model able to reproduce realistic scenarios. We analyse the computational improvement and the accuracy of the ROM results with respect to those of the full-order model (FOM)
Association between competition and facilitation processes and vegetation spatial patterns in alpha steppes
11 páginas, 5 figuras, 3 tablas.-- El PDF del artĂculo es la versiĂłn post-print.In semiarid ecosystems, the self-organized spatial patterns of plants associated with catastrophic shifts can emerge from a variety of processes. In this study, on moderate slopes where Stipa tenacissima cover was high, the self-organization of some of the typical species of semiarid Mediterranean matorral (Phlomis purpurea, Sideritis oxteosylla, Helianthemum almeriense, and Brachypodium retusum) was negatively correlated with Stipa cover. The extent of Stipa cover did not affect desert pioneer species, such as Artemisia herba-alba, Fagonia cretica, and Launaea lanifera. On pronounced slopes, the self-organizing structure of brushwood vegetation did not vary predictably with the amount of Stipa cover. We examined the competition/facilitation processes associated with self-organizing patterns in the dwarf shrub (Phl. purpurea) and the half shrub (H. almeriense). The developmental stability of H. almeriense was positively correlated with Stipa cover, which was expected because they are associated species in this seral thyme brushwood community. Indeed, facilitation processes were manifested by the developmental stability increases under the Stipa canopy, particularly on high slope areas, where Stipa is less competitive. In Phl. purpurea, negative feedback processes from competition with Stipa were manifested where Stipa cover was high and on low slopes (developmental instability increased). In general, competition with Stipa on low slopes tended to decrease plant self-organization.We gratefully acknowledge support from the Spanish
CICYT (Project REN2002-04668/GLO, Efectos de la
fragmentaciĂłn y uso del suelo en la conservaciĂłn y
dinámica de las zonas esteparias Mediterráneas).Peer reviewe
Prey choice, provisioning behaviour, and effects of early nutrition on nestling phenotype of titmice
[EN] It is generally assumed that blue and great tits (Cyanistes caeruleus, Parus major) compete for the same type of food (Lepidoptera larvae) during the breeding season and that the former have some advantage because they are usually earlier and can exploit small caterpillars that are often more abundant and are not consumed by great tits. However, it is not clear whether, when confronted with similar circumstances (e.g., nestling demand), blue and great tits show similar preferences for a particular caterpillar type. In this 2-y study, we compare the diet of both tit species in detail by controlling for hatching date and brood size. We also examine how the contribution of caterpillars and spiders to the diet is related to nestling development. A positive relationship was found between the percentage of spiders in the diet and nestling tarsus length in both species, reinforcing the idea that neonatal nutrition could have a strong influence on nestling phenotype (e.g., offspring size). Such a correlation may arise because spiders contain a high level of taurine, an essential nutrient in the early development of young, and/or this prey type contains more calcium than other food items, which may affect the rate of nestling bone mineralization. Blue tits fed their young double the number of tortricid larvae in comparison with great tits, whereas the latter showed a clear preference for noctuids and exploited, with a low frequency, a type of larvae not consumed by blue tits, hairy caterpillars (Lasiocampidae). Our results point to resource partitioning by these species in this forest ecosystem and contribute to a better understanding of feeding ecology of titmice, which is particularly timely in a global warming context [FR] Il est gĂ©nĂ©ralement admis que les mĂ©sanges bleues (Cyanistes caeruleus) et les mĂ©sanges charbonnières (Parus major) se font compĂ©tition pour le mĂŞme type de nourriture (larves de lĂ©pidoptères) durant la pĂ©riode de reproduction. Il est Ă©galement admis que les mĂ©sanges bleues possèdent un certain avantage, car elles se reproduisent plus tĂ´t et mangent de petites chenilles souvent plus abondantes qui ne sont pas consommĂ©es par les mĂ©sanges charbonnières. Cependant, il n'est pas clair si dans les mĂŞmes conditions (ex. de demande en nourriture des oisillons), les mĂ©sanges bleues et charbonnières prĂ©fèrent les mĂŞmes types de chenilles. Dans cette Ă©tude de 2 ans, nous avons comparĂ© en dĂ©tail les rĂ©gimes alimentaires des 2 espèces de mĂ©sanges en contrĂ´lant pour la date de ponte et la taille de la couvĂ©e. Nous avons aussi examinĂ© si les contributions des chenilles et des araignĂ©es au rĂ©gime alimentaire Ă©taient reliĂ©es au dĂ©veloppement des oisillons. Chez les 2 espèces, une relation positive a Ă©tĂ© trouvĂ©e entre le pourcentage d'araignĂ©es dans le rĂ©gime alimentaire et la longueur du tarse des oisillons renforçant ainsi l'idĂ©e que la nutrition nĂ©onatale peut avoir une grande influence sur le phĂ©notype des oisillons (ex. la taille des jeunes). Une telle corrĂ©lation peut rĂ©sulter du fait que les araignĂ©es ont un taux Ă©levĂ© de taurine, un nutriment essentiel au dĂ©veloppement prĂ©coce des jeunes, et/ou que ce type de proie contient plus de calcium que d'autres aliments ce qui peut influencer le taux de minĂ©ralisation des os chez les oisillons. Les mĂ©sanges bleues ont nourri leurs jeunes avec deux fois plus de larves de tortricidĂ©s que les mĂ©sanges charbonnières qui elles ont montrĂ© une nette prĂ©fĂ©rence pour les noctuidĂ©s. Ces dernières ont aussi consommĂ©, quoique peu frĂ©quemment, des livrĂ©es (Lasiocampidae), un type de larves boudĂ© par les mĂ©sanges bleues. Nos rĂ©sultats pointent vers une division des ressources entre ces espèces dans cet Ă©cosystème forestier et contribuent Ă une meilleure comprĂ©hension de l'Ă©cologie alimentaire des mĂ©sanges ce qui est particulièrement utile dans un contexte de rĂ©chauffement climatiqueV. GarcĂa-Navas was supported by a FPI predoctoral fellowship (Spanish Ministry of Science and Innovation (MICINN)-European Social Fund). This study was financed by the MICINN (grant reference: GCL2007-61395)Peer Reviewe
The Type 1 and Type 2 AGN dichotomy according to their ZTF optical variability
The scarce optical variability studies in spectrally classified Type 2 active
galactic nuclei (AGNs) have led to the discovery of anomalous objects that are
incompatible with the simplest unified models (UM). This paper focuses on the
exploration of different variability features that allows to separate between
obscured, Type 2 AGNs, and the variable, unobscured Type 1s. We analyse
systematically the Zwicky Transient Facility, 2.5 years long light curves of ~
15000 AGNs from the Sloan Digital Sky Survey Data Release 16, which are
generally considered Type 2s due to the absence of strong broad emission lines
(BELs). Consistently with the expectations from the UM, the variability
features are distributed differently for distinct populations, with spectrally
classified weak Type 1s showing 1 order of magnitude larger variances than the
Type 2s. We find that the parameters given by the damped random walk model
leads to broader H{\alpha} equivalent width for objects with {\tau}_g > 16 d
and long term structure function SF{\infty},g> 0.07 mag. By limiting the
variability features, we find that ~ 11 per cent of Type 2 sources show
evidence for optical variations. A detailed spectral analysis of the most
variable sources (~1 per cent of the Type 2 sample) leads to the discovery of
misclassified Type 1s with weak BELs and changing-state candidates. This work
presents one of the largest systematic investigations of Type 2 AGN optical
variability to date, in preparation for future large photometric surveys.Comment: Accepted for publication in MNRAS. 13 pages, 9 figure
Inferring Energy Bounds via Static Program Analysis and Evolutionary Modeling of Basic Blocks
The ever increasing number and complexity of energy-bound devices (such as
the ones used in Internet of Things applications, smart phones, and mission
critical systems) pose an important challenge on techniques to optimize their
energy consumption and to verify that they will perform their function within
the available energy budget. In this work we address this challenge from the
software point of view and propose a novel parametric approach to estimating
tight bounds on the energy consumed by program executions that are practical
for their application to energy verification and optimization. Our approach
divides a program into basic (branchless) blocks and estimates the maximal and
minimal energy consumption for each block using an evolutionary algorithm. Then
it combines the obtained values according to the program control flow, using
static analysis, to infer functions that give both upper and lower bounds on
the energy consumption of the whole program and its procedures as functions on
input data sizes. We have tested our approach on (C-like) embedded programs
running on the XMOS hardware platform. However, our method is general enough to
be applied to other microprocessor architectures and programming languages. The
bounds obtained by our prototype implementation can be tight while remaining on
the safe side of budgets in practice, as shown by our experimental evaluation.Comment: Pre-proceedings paper presented at the 27th International Symposium
on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur,
Belgium, 10-12 October 2017 (arXiv:1708.07854). Improved version of the one
presented at the HIP3ES 2016 workshop (v1): more experimental results (added
benchmark to Table 1, added figure for new benchmark, added Table 3),
improved Fig. 1, added Fig.
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