411 research outputs found
Pairs-Production of Higgs in Association with Bottom Quarks Pairs at Colliders
In a previous paper, we studied the Higgs pair production in the standard
model with the reaction . Based on this, we study
the Higgs pair production via . We evaluate the
total cross section of and calculate the number total of events
considering the complete set of Feynman diagrams at tree-level, and compare
this process with the process . The numerical
computation is done for the energy which is expected to be available at a
possible Next Linear Collider with a center-of-mass energy and luminosity 1000 .Comment: 12 pages, 6 figure
Alimentación de modelos cuantitativos con información subjetiva: aplicación Delphi en la elaboración de un modelo de imputación del gasto turístico individual en Catalunya
Symmetrical Observability of Kinematic Parameters in Symmetrical Parallel Mechanisms
This article presents an application of symmetry group theory in kinematic identification of parallel mechanisms of nlegs legs -- Kinematic Identification implies the estimation of the actual geometrical parameters (as opposed to nominal ones) of a physical mechanism -- For a symmetric mechanism, KI requires configuring sets of leg positions with symmetrical observability – This article presents as main contributions: (i) a conjecture that allows mapping the symmetries of the mechanism into the active-joint workspace, (ii) a set of necessary conditions to express leg parameters in coordinate systems which allow symmetrical observability, and (iii) a procedure for exploiting symmetries in pose selection for kinematic identification of symmetrical parallel mechanisms -- For the kinematic identification itself, we adopt a divide-and-conquer (DC) identification protocol -discussed by us in another publication- in which each leg of the mechanism is independently identified by using the inverse calibration method -- In this article we emphasize how to exploit the symmetries existent in (nlegs − 1) legs of the parallel mechanism allowing to apply to other legs the symmetry-transformed sample protocol used for the kinematic identification of a reference leg -- The symmetrical observability of sets of leg parameters allows to reduce the costs of the pose selection procedure by a factor of (1/nlegs) compared to a complete DC procedure in which the poses of each leg are selected independently -- The pose selection is carried out only for the reference leg -- For the (nlegs−1) remaining legs the poses are dictated by symmetry operations performed onto the poses of the reference leg -- An application of the symmetrical observability is presented through the simulated kinematic identification of a 3RRR symmetrical parallel mechanismPolytechnic School of the University of São PauloSitio webIndicaciones, Associação Brasileira de Métodos Computacionais em Engenharia, International Association for Computational Mechanics, International Congress and Convention Association, Conheça o São Paulo é Tudo de Bom, Embratur, PETROBRA
Alimentación de modelos cuantitativos con información subjetiva: aplicación Delphi en la elaboración de un modelo de imputación del gasto turístico individual en Catalunya
El presente artículo presenta un estudio realizado para el Institut d'Estadística de Catalunya, donde se ha aplicado una técnica que trabaja con información subjetiva (el Método Delphi) para obtener unos datos que puedan ser empleados en la alimentación parcial de un modelo matemático, que se nutre principalmente de datos estadísticos (objetivos), con el fin de incrementar la utilidad global del modelo.
El artículo justifica la utilización en determinadas circunstancias de la información subjetiva, describe el método Delphi y plantea una serie de proposiciones referentes a la utilidad, empleo y mejora de esta técnica que se ven refrendadas en el caso expuesto
Hardware-accelerated Web Visualization of Vector Fields. Case Study in Oceanic Currents
Visualization of vector fields plays an important role in research activities nowadays -- Increasing web applications allow a fast, multi-platform and multi-device access to data -- As a result, web applications must be optimized in order to be performed heterogeneously as well as on high-performance as on low capacity devices -- This paper presents a hardware-accelerated scheme for integration-based flow visualization techniques, based on a hierarchical integration procedure which reduces the computational effort of the algorithm from linear to logarithmic, compared to serial integration methodologies -- The contribution relies on the fact that the optimization is only implemented using the graphics application programming interface (API), instead of requiring additional APIs or plug-ins -- This is achieved by using images as data storing elements instead of graphical information matrices -- A case study in oceanic currents is implemente
Inhibición de Aspergillus Niger en la producción de aflatoxina B1.
Se estudió la inhibición de una toxina fúngica mediante la interacción de hongos del Género Aspergillus. La interacción tuvo lugar en medio sólido (Gy – Agar), cuando se agregaron diferentes proporciones de suspensiones conidiales de Aspergillus flavus y Aspergillus níger a una misma placa de Petri y se incubó por espacio de una semana. Luego de una semana de incubación en el medio sólido a 28 ºC y en
oscuridad, Aspergillus flavus (productor de aflatoxina B1) y Aspergillus níger mostraron diferentes tasa de crecimiento. Se pudo observar tanto macro como
microscópicamente que la tasa de crecimiento de conidiación de A.níger fue siempre mayor que la de A. flavus. A las placas incubadas con diferentes proporciones conidiales se les determinó la presencia de Aflatoxina B1 (AFB1), por cromatografía de capa fina (TLC). Para determinadas relaciones inoculadas, se comprobó la ausencia de la toxina (AFB1), lo cual nos estaría indicando un mecanismo natural inhibitorio de Aspergillus níger sobre cepas de A. flavus fuertemente productoras de AF
A search for pre- and proto-brown dwarfs in the dark cloud Barnard 30 with ALMA
In this work we present ALMA continuum observations at 880 m of 30
sub-mm cores previously identified with APEX/LABOCA at 870m in the Barnard
30 cloud. The main goal is to characterize the youngest and lowest mass
population in the cloud. As a result, we report the detection of five (out of
30) spatially unresolved sources with ALMA, with estimated masses between 0.9
and 67 M. From these five sources, only two show gas emission. The
analysis of multi-wavelength photometry from these two objects, namely B30-LB14
and B30-LB19, is consistent with one Class II- and one Class I low-mass stellar
object, respectively. The gas emission is consistent with a rotating disk in
the case of B30-LB14, and with an oblate rotating envelope with infall
signatures in the case of LB19. The remaining three ALMA detections do not have
infrared counterparts and can be classified as either deeply embedded objects
or as starless cores if B30 members. In the former case, two of them (LB08 and
LB31) show internal luminosity upper limits consistent with Very Low Luminosity
objects, while we do not have enough information for LB10. In the starless core
scenario, and taking into account the estimated masses from ALMA and the
APEX/LABOCA cores, we estimate final masses for the central objects in the
substellar domain, so they could be classified as pre-BD core candidates.Comment: Published in A&
Web based hybrid volumetric visualisation of urban GIS data: Integration of 4D Temperature and Wind Fields with LoD-2 CityGML models
City models visualisation, buildings, structures and volumetric information, is an important task in Computer Graphics and Urban Planning -- The different formats and data sources involved in the visualisation make the development of applications a big challenge -- We present a homogeneous web visualisation framework using X3DOM and MEDX3DOM for the visualisation of these urban objects -- We present an integration of different declarative data sources, enabling the utilization of advanced visualisation algorithms to render the models -- It has been tested with a city model composed of buildings from the Madrid University Campus, some volumetric datasets coming from Air Quality Models and 2D layers wind datasets -- Results show that the visualisation of all the urban models can be performed in real time on the Web -- An HTML5 web interface is presented to the users, enabling real time modifications of visualisation parameter
INHIBICIÓN DE ASPERGILLUS NÍGER EN LA PRODUCCIÓN DE AFLATOXINA B1
Se estudió la inhibición de una toxina fúngica mediante la interacción de hongos del Género Aspergillus. La interacción tuvo lugar en medio sólido (Gy - Agar), cuando se agregaron diferentes proporciones de suspensiones conidiales de Aspergillus flavus y Aspergillus níger a una misma placa de Petri y se incubó por espacio de una semana. Luego de una semana de incubación en el medio sólido a 28 °C y en oscuridad, Aspergillus flavus (productor de aflatoxina B1 ) y Aspergillus níger mostraron diferentes tasa de crecimiento. Se pudo observar tanto macro como microscópicamente que la tasa de crecimiento de conidiación de A.níger fue siempre mayor que la de A. flavus. A las placas incubadas con diferentes proporciones conidiales se les determinó la presencia de Aflatoxina B1 (AFB), por cromatografia de capa fina (TLC). Para determinadas relaciones inoculadas, se comprobó la ausencia de la toxina (AFB), lo cual nos estaría indicando un mecanismo natural inhibitorio de Aspergillus níger sobre cepas de A. flavus fuertemente productoras de AF
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