LHCb Silicon Tracker DAQ and ECS Online Systems Esperante, Daniel; Rodriguez, P; Buchler, A ...
IEEE transactions on nuclear science,
2010-April, 2010-04-00, 20100401, Letnik:
57, Številka:
2
Journal Article
Recenzirano
The LHCb experiment at CERN is designed to perform precision measurements of b quark decays. The Silicon Tracker plays a crucial role in reconstructing particle trajectories and consists of two ...silicon micro-strip detectors, the Tracker Turicensis and the Inner Tracker. The radiation environment and the magnetic field represent new challenges for the implementation of the Experiment Control System (ECS) and the data acquisition (DAQ). The DAQ has to deal with ~272 000 analog read-out channels and real-time DAQ at a rate of ~ 1.1 MHz with data processing at the Trigger Electronics and L1 (TELL1) board level. The TELL1 real-time algorithms for clustering thresholds and other computations run on dedicated FPGAs. After data processing the total throughput amounts to about 6.4 GB from an input data rate of ~ 337 GB per second. The ECS is based on the hierarchical finite state machine paradigm and allows distributed control access and multi-platform use. The ECS is able to control and monitor the detector hardware infrastructure (power supplies, DAQ electronics ...) as well as monitor the environmental parameters. It can also take automated actions on warnings or alarms. Finally a completely independent, hardware based safety system ensures the detector safe operation.
Preparation and Structures of Hydrogen Ordered Phases of Ice Salzmann, Christoph G; Radaelli, Paolo G; Hallbrucker, Andreas ...
Science (American Association for the Advancement of Science),
03/2006, Letnik:
311, Številka:
5768
Journal Article
Recenzirano
Two hydrogen ordered phases of ice were prepared by cooling the hydrogen disordered ices V and XII under pressure. Previous attempts to unlock the geometrical frustration in hydrogen-bonded ...structures have focused on doping with potassium hydroxide and have had success in partially increasing the hydrogen ordering in hexagonal ice I (ice Ih). By doping ices V and XII with hydrochloric acid, we have prepared ice XIII and ice XIV, and we analyzed their structures by powder neutron diffraction. The use of hydrogen chloride to release geometrical frustration opens up the possibility of completing the phase diagram of ice.
The amount of software in cars grows exponentially. Driving forces of this development are the availability of cheaper and more powerful hardware as well as the demand for innovation through new ...functionality. The rapidly growing significance of software and software-based functionality is at the root of various challenges in the automotive industries, concerning their organization, definition of key competencies, processes, methods, tools, models, product structures, division of labor, logistics, maintenance, and long term strategies 1,2.
A variety of online courses and even degree programs have begun to appear as standard offerings from a broad spectrum of educational and training institutions. Often, these courses consist purely of ...web-based access to traditional textual and graphical course materials, while others have tried to provide real-time audio or video access to traditional classes using modern communications technologies. This paper describes another approach-the Lectures on Demand in Asynchronous Learning Networks (ALN) methodology-in using information technology to enhance the learning experience for conventional on-campus students, as well as for those students whose circumstances require that they be asynchronous in time or space with respect to fellow students and instructional staff. In this approach, students are able to 'attend' classes in real time via the Internet, as well as to access asynchronously digitally stored video material with hyperlinks to other online resources, such as mailing lists or chat sessions, at any time. In addition to the simple delivery of class materials, current and emerging Internet-based communication technologies permit beneficial interaction in real-time and asynchronously among students and between students and instructor, which is a key for effective learning. The paper discusses the pedagogical and technical issues involved in this approach, and describes a variety of mechanisms to provide enhanced live and archived classes.
We present an analytical and numerical study of the velocity distribution function of self gravitating collisionless particles, which include dark matter and star clusters. We show that the velocity ...distribution derived through the Eddington’s formula is identical to the analytical one derived directly from the generalized entropy of non-extensive statistical mechanics. This implies that self gravitating collisionless structures are to be described by non-extensive thermo-statistics. We identify a connection between the density slope of dark matter structures, γ, from ρ∼r−γ, and the entropic index, q, from the generalized entropy, Sq. Our numerical result confirms the analytical findings of earlier studies and clarifies which is the correct connection between the density slope and the entropic index. We use this result to conclude that from a fundamental statistical mechanics point of view the central density slope of self gravitating collisionless dark matter structures is not constrained, and even cored dark matter structures are allowed with γ=0. We find that the outer density slope is bounded by γ=10/3.
Cumulene sp-carbon molecular wires C2 Fc(Ph)CC(Ph)Fc up to C7 Fc(Ph)CCCCCCC(Ph)Fc endcapped by two electroactive ferrocenyl groups are presented in this report. Synthetically, ferrocenyl ...cumulenes can be built-up by a modular strategy using C1 synthon ferrocenyl(phenyl)ketone as starting material with various acetylenic/propargylic/homopropargylic C2−C5 reagents, taking into account and exploiting the efficient stabilization of an electron-deficient carbenium center by an adjacent ferrocenyl moiety. With increasing cumulene chain length the reactivity of cumulenes increases considerably, indicating steric protection as the main requirement for bulk stability. Even cumulenes C2, C4, and C6 are conjugated “molecular wires” effecting electronic communication between the terminal ferrocenyl substituents, whereas odd cumulenes C3, C5, and C7 are nonconjugated and electronically decoupled due to their orthogonal terminal π-systems. Electrochemically, separate redox waves can be detected up to a C6 cumulene spacer, but the electronic communication between the endcapping redox-active ferrocenyl substituents decreases with increasing cumulene length.
Previous studies have shown that leptin can regulate the adrenocortical axis. Neonatal rodents exhibit a period of adrenal hyporesponsiveness to stress in the first 2 wk of life, and we determined ...the role of leptin as a mediator of this process. We examined the direct effects of leptin on neonatal adrenal steroidogenic responses to ACTH under basal conditions and after 24-h maternal separation. In isolated adrenocortical cells from as early as postnatal d 5 (PND5) and throughout the neonatal period, acute (2.5 h) incubation with leptin significantly inhibited ACTH-stimulated corticosterone and aldosterone secretion without affecting cAMP production. In PND10 pups, 24-h maternal separation and the resulting rapid decline in plasma leptin levels increased basal corticosterone and aldosterone secretion in vivo and in isolated cells, but did not modify the ability of leptin to inhibit stimulated steroid production in vitro. Maternal separation in PND10 pups increased adrenal expression of steroidogenic acute regulatory protein (StAR) and peripheral-type benzodiazepine receptor (PBR) proteins as well as all steroidogenic enzymes measured (3β-hydroxysteroid dehydrogenase, P450C11B1, and P450C11B2). Leptin (1 mg/kg body weight, ip) replacement during maternal separation did not affect basal corticosterone output, but reduced corticosterone secretion and StAR and PBR protein expression induced by exogenous ACTH challenge (20 or 80 μg/kg body weight, ip). These results indicate that leptin inhibits ACTH-stimulated secretion of corticosterone and aldosterone, at least through a rapid reduction in the expression of StAR and PBR protein in the neonatal adrenal gland. As leptin concentrations in pups are controlled to a large extent by the maternal diet, these results emphasize the key role of leptin to mediate the maternal influence on the adrenocortical axis of the infant.
On compressing low-density amorphous ice (LDA) at 125 K up to 1.6 GPa, two distinct density steps accompanied by heat evolution are observable in pressure-density curves. Samples recovered to 77 K ...and 1 bar after the first and second steps show the x-ray diffraction pattern of high-density amorphous ice (HDA) and very HDA (VHDA), respectively. The compression of the once formed HDA takes place linearly in density up to 0.95 GPa, where nonlinear densification and HDA --> VHDA conversion is initiated. This implies a stepwise formation process LDA--> HDA --> VHDA at 125 K, which is to the best of our knowledge the first observation of a stepwise amorphous-amorphous-amorphous transformation sequence. We infer that the relation of HDA and VHDA is very similar to the relation between LDA and HDA except for a higher activation barrier between the former. We discuss the two options of thermodynamic versus kinetic origin of the phenomenon.
A new approach to developing Web-enabled environments for remote diagnostics, maintenance, and experimentation in engineering is based on a middleware layer that uses a Java-lntemet-Labview server to ...provide communication between Java programs and Labview virtual instruments. The authors illustrate their technique by applying it to the development of a complete Web-enabled application for remote control of a thermal process.
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