The online silicon vertex tracker (SVT) is the new trigger processor dedicated to the two-dimensional (2-D) reconstruction of charged particle trajectories at the Level 2 of the Collider Detector at ...Fermilab (CDF) trigger. The SVT links the digitized pulse heights found within the silicon vertex detector to the tracks reconstructed in the central outer tracker by the Level 1 fast-track finder. Preliminary tests of the system took place during the October 2000 commissioning run of the Tevatron Collider. During the April-October 2001 data taking, it was possible to evaluate the performance of the system. In this paper, we review the tracking algorithms implemented in the SVT and we report on the performance achieved during the early phase of run II.
Adult mesenchymal stem cells (MSCs) derived from bone marrow contribute to the regeneration of multiple types of mesenchymal tissues. Here we describe the functional role of a novel form of ...cross-talk between the transforming growth factor beta 1 (TGF- beta 1) and Wnt signaling pathways in regulating the activities of human MSCs. We show that TGF- beta 1 induces rapid nuclear translocation of beta -catenin in MSCs in a Smad3-dependent manner. Functionally, this pathway is required for the stimulation of MSC proliferation and the inhibition of MSC osteogenic differetiation by TGF- beta 1, likely through the regulation of specific downstream target genes. These results provide evidence for a new mode of cooperation between the TGF- beta and Wnt signaling pathways in this specific cellular context and suggest a potentially important role for this distinct signaling pathway in the control of self-renewal and differentiation of a specific type of MSCs.
The accumulation of deformation affects the lifetime of a mohocristal submitted to low cyclic mechanical and thermal loading. An analytical method was developed considering the damages due to cyclic ...and axial plastic and creep deformation. The method was checked with tesst in vacuum on specimens of rr onocrystals with different space orientation, also specimens with stress concentrators. The distribution of stressses was FEM modelled. The fracture depends on the space orientation of the specimen and of the loading parameters. A new experimental-computational method using deformation-fracture criteria is suggested for the evaluation of the crystal life time.
The aims of this study were (1) to characterize calcium signaling in rat cortex induced by repeated in vitro application of the glutamatergic agonists L-glutamate, NMDA, AMPA and DHPG, (2) to analyze ...the influence of transient severe hypobaric hypoxia (180 Torr) administered in vivo on calcium responses to stimulation of glutamate receptors by their agonists, and (3) to evaluate the effects of preconditioning with intermittent mild hypobaric hypoxia (360 Torr) 24 h before the severe hypoxia, on these Ca2+ responses. Intracellular Ca2+ dynamics was studied using the fluorescent probes fura-2 and chlortetracycline to monitor free and bound calcium (Cai and Cab) respectively. In control cortical slices, application of L-glutamate, NMDA and AMPA induced concomitant increases in Cai and Cab, reflecting Ca2+ influx and its intracellular accumulation in neurons. DHPG, an agonist of group I mGlu receptors induced a decrease in Cab accompanied by a rise in Cai levels, indicating Ca2+ mobilization. In cortical slices collected 24 h after severe hypoxia, the responses of Cab to glutamate administration were increased, DHPG-induced shifts were reversed, the increase in Cab after the first application of AMPA was reduced, while after the second, Cab rises were potentiated, and the increases in Cab evoked by NMDA application were slightly suppressed. The alterations of responses in Cab to the selective agonists were completely prevented by preconditioning with mild hypoxia. Our results suggest that protection of normal glutamatergic calcium signaling contributes to tolerance to hypoxia induced by preconditioning.
Decimation filters are still the most complex and valuable superconductor digital circuits, so it is natural to use them to compare different design techniques. In the paper we discuss two new ...techniques. The first deals with the DC biasing scheme. For debugging purposes it is convenient to use separate power lines for different functional blocks. However, the lines occupy extra space, which could be unacceptable for a final design, when the decimation filters become part of larger circuits, for example, low-pass or band-pass ADCs. We will discuss an efficient rewiring technique that saves space during the connection of separate power lines after the circuit is debugged. The second technique is a selective use of micro-strip lines. Our solution contrasts with "extreme" recommendations for micro-strip lines as a universal tool for inter cell connections. More specifically for each connection we select either Josephson transmission or micro-strip line connection to keep the occupied area as small as possible. This highly "custom" design is possible due to parametric cell technique that dramatically accelerates the design procedure. In particular, we easily converted the circuit initially developed for 1 kA/cm 2 standard HYPRES technology to the advanced technology with higher (4.5 kA/cm 2 ) critical current density. The filter has 20 GHz and 40 GHz target sampling frequencies for 1kA/cm 2 and 4.5 kA/cm 2 fabrication processes respectively. The circuits are fully operational at low frequency.
Online control of thickness of as-deposited coatings is of great importance because it directly affects the quality of protective coatings. We present a novel approach that enables online, real-time ...and non-contact measurements thickness of thermally sprayed coatings. The proposed technique uses dynamic speckles generated by rapidly deflecting laser beam. Within 10 ms the system can scan 500 times a small area of the deposited layer thus resulting in measurement accuracy of 5 microns irrespectively of the layer roughness. In comparison with traditional optical triangulation technique of distance measurements, our system has following advantages: (i) much simpler optical scheme that includes conventional photodiode to measure the scattered light, (ii) much simpler electronics for real-time data processing, (iii) much higher speed of measurements.
The quadrupoles and sextupoles for the Swiss Light Source had severe requirements on the manufacturing tolerances and the alignment of their magnetic axis. The 306 multipoles were manufactured, and ...magnetically measured at BINP and after delivery also at PSI. The features of manufacturing and precise magnetic measurements of SLS multipoles are discussed.
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