6,704 research outputs found
Characterization of Thin p-on-p Radiation Detectors with Active Edges
Active edge p-on-p silicon pixel detectors with thickness of 100 m were
fabricated on 150 mm Float zone silicon wafers at VTT. By combining measured
results and TCAD simulations, a detailed study of electric field distributions
and charge collection performances as a function of applied voltage in a p-on-p
detector was carried out. A comparison with the results of a more conventional
active edge p-on-n pixel sensor is presented. The results from 3D spatial
mapping show that at pixel-to-edge distances less than 100 m the sensitive
volume is extended to the physical edge of the detector when the applied
voltage is above full depletion. The results from a spectroscopic measurement
demonstrate a good functionality of the edge pixels. The interpixel isolation
above full depletion and the breakdown voltage were found to be equal to the
p-on-n sensor while lower charge collection was observed in the p-on-p pixel
sensor below 80 V. Simulations indicated this to be partly a result of a more
favourable weighting field in the p-on-n sensor and partly of lower hole
lifetimes in the p-bulk.Comment: 23 pages, 16 figures, 1 tabl
Gravitation and thermodynamics: The einstein equation of state revisited
We perform an analysis where Einstein\u27s field equation is derived by means of very simple thermodynamical arguments. Our derivation is based on a consideration of the properties of a very small, spacelike two-plane in a uniformly accelerating motion. © 2009 World Scientific Publishing Company
Electronic stopping calculated using explicit phase shift factors
Predicting range profiles of low-energy (0.1–10 keV/amu) ions implanted in materials is a long-standing problem of considerable theoretical and practical interest. We combine here the best available method for treating the nuclear slowing down, namely a molecular-dynamics range calculation method, with a method based on density-functional theory to calculate electronic slowing down for each ion-target atom pair separately. Calculation of range profiles of technologically important dopants in Si shows that the method is of comparable accuracy to previous methods for B, P, and As implantation of Si, and clearly more accurate for Al implantation of Si.Peer reviewe
Simulation study of signal formation in position sensitive planar p-on-n silicon detectors after short range charge injection
Segmented silicon detectors (micropixel and microstrip) are the main type of detectors used in the inner trackers of Large Hadron Collider (LHC) experiments at CERN. Due to the high luminosity and eventual high fluence of energetic particles, detectors with fast response to fit the short shaping time of 20-25 ns and sufficient radiation hardness are required. Charge collection measurements carried out at the Ioffe Institute have shown a reversal of the pulse polarity in the detector response to short-range charge injection. Since the measured negative signal is about 30-60% of the peak positive signal, the effect strongly reduces the CCE even in non-irradiated detectors. For further investigation of the phenomenon the measurements have been reproduced by TCAD simulations. As for the measurements, the simulation study was applied for the p-on-n strip detectors similar in geometry to those developed for the ATLAS experiment and for the Ioffe Institute designed p-on-n strip detectors with each strip having a window in the metallization covering the p(+) implant, allowing the generation of electron-hole pairs under the strip implant. Red laser scans across the strips and the interstrip gap with varying laser diameters and Si-SiO2 interface charge densities (Q(f)) were carried out. The results verify the experimentally observed negative response along the scan in the interstrip gap. When the laser spot is positioned on the strip p(+) implant the negative response vanishes and the collected charge at the active strip increases respectively. The simulation results offer a further insight and understanding of the influence of the oxide charge density in the signal formation. The main result of the study is that a threshold value of Q(f), that enables negligible losses of collected charges, is defined. The observed effects and details of the detector response for different charge injection positions are discussed in the context of Ramo's theorem.Peer reviewe
Enfoques recientes para modelizar el riesgo de tormentas y fuego en los bosques europeos y su integración
The aim of this paper is to discuss the different recently developed empirical and mechanistic modelling approaches for assessing the risk of wind and fire damage to forests. Additionally the work will explore possible ways to integrate these approaches, including feedback mechanisms, into growth and yield models and decision support tools used in forestry. The integration of mechanistic and empirical storm risk models, as well as an empirical/mechanistic fire risk model into growth simulators is demonstrated and future challenges and options for risk modelling and for creating complex decision support tools, including growth simulators, meteorological components and risk modules, are discussed.El objetivo de este trabajo es analizar los diferentes modelos empíricos y mecanicistas que se han desarrollado recientemente para evaluar el riesgo de daños por el viento y el fuego en los bosques. Además, el trabajo explora las posibles formas de integrar estos enfoques, incluyendo mecanismos de retroalimentación, en los modelos de crecimiento y produccion y en las herramientas de apoyo a la toma de decisiones utilizadas en el sector forestal. Se muestra la integración de modelos mecanicistas y empíricos de riesgo a tormentas, así como un modelo empírico/mecanicista de riesgo de incendio en los simuladores de crecimiento y se discuten los retos futuros y las opciones para la modelización de riesgos y para la creación de complejas herramientas de apoyo a la toma de decisiones, incluyendo simuladores de crecimiento, componentes meteorológicos y módulos de riesgo
Pim-1 kinase phosphorylates RUNX family transcription factors and enhances their activity
BACKGROUND: The pim family genes encode oncogenic serine/threonine kinases which in hematopoietic cells have been implicated in cytokine-dependent signaling as well as in lymphomagenesis, especially in cooperation with other oncogenes such as myc, bcl-2 or Runx family genes. The Runx genes encode α-subunits of heterodimeric transcription factors which regulate cell proliferation and differentiation in various tissues during development and which can become leukemogenic upon aberrant expression. RESULTS: Here we have identified novel protein-protein interactions between the Pim-1 kinase and the RUNX family transcription factors. Using the yeast two-hybrid system, we were able to show that the C-terminal part of human RUNX3 associates with Pim-1. This result was confirmed in cell culture, where full-length murine Runx1 and Runx3 both coprecipitated and colocalized with Pim-1. Furthermore, catalytically active Pim-1 kinase was able to phosphorylate Runx1 and Runx3 proteins and enhance the transactivation activity of Runx1 in a dose-dependent fashion. CONCLUSION: Altogether, our results suggest that mammalian RUNX family transcription factors are novel binding partners and substrates for the Pim-1 kinase, which may be able to regulate their activities during normal hematopoiesis as well as in leukemogenesis
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