Status of the physics validation studies using Geant4 in ATLAS

The new simulation for the ATLAS detector at LHC is performed using Geant4 in a complete OO/C++ environment. In this framework the simulation of the various test beams for the different ATLAS subdetectors offers an excellent opportunity to perform physics validation studies over a wide range of physics domains: the electromagnetic processes, the individual hadronic interactions, the electromagnetic and hadronic signals in calorimeters. The simulation is implemented by paying special attention to all details of the experimental layout and by testing all possible physics processes which may be of relevance to the specific detector under test: the resulting simulation programs are often more detailed than the corresponding Geant3-based simulation suites. In this paper we present relevant features of muon, electron and pion signals in various ATLAS detectors. All remaining discrepancies between Geant4 and test-beam data are currently being addressed and progress is continuous. This work shows that Geant4 is becoming a mature and useful product for simulating specific features of large-scale detector systems.Comment: CHEP '03 proceedings, 7 pages, 22 figure

Genome scan of Kenyan Themeda triandra populations by AFLP markers reveals a complex genetic structure and hints for ongoing environmental selection

Abstract Tropical and subtropical rangeland systems provide core ecosystem services for the welfare of human populations that rely on readiness and quality of forage resources. However, forage species are still widely overlooked by molecular biology studies. In the present study, we employ 366 AFLP markers to provide the first description of the genetic landscape of three Kenyan populations of Themeda triandra Forssk., a key wild grass forage species. By including Australian T. triandra accessions and other closely related species in a molecular phylogeny, we provide a first evaluation of the relationships existing between African and Australian germplasm. Genetic diversity, population genetic structure and recombination rates in Kenyan T. triandra populations were investigated in detail. GPS coordinates of each sampled population were used to retrieve meteorological data at specific locations, and environmental factors likely contributing to T. triandra genetic differentiation were taken into consideration using a correlative approach based on outlier loci distribution. The use of molecular markers unveiled some previously unknown aspects about the biology of T. triandra , namely: i) African and Australian T. triandra genotypes analyzed in this study are genetically undistinguishable, ii) sexual recombination of Kenyan T. triandra is likely to play a major role in its reproduction, and iii) environmental characteristics of the collection sites are correlated with the allelic distribution of a limited set of loci under selection

Enhancing Luxury through Stained Glass, from Asia Minor to Italy

This study addresses the use of colored glazed windows in the interior decoration of Byzantine churches dating from the sixth to the twelfth century. In light of new evidence provided by recent excavations, I ask the question whether, or to what extent, developments in Byzantium can be associated with earlier or foreign architectural traditions. I attempt to demonstrate that there was an evolution in glassmaking techniques, and in the forms and ways glass was applied to architectural interior

The full detector simulation for the Atlas experiment: status and outlook

The simulation of the ATLAS detector is a major challenge, given the complexity of the detector and the demanding environment of the LHC. The apparatus, one of the biggest and most complex ever designed, requires a detailed, flexible and, if possible, fast simulation which is needed already today to deal with questions related to design optimization, to issues raised by staging scenarios, and of course to enable detailed physics studies to lay the basis for the first physics discoveries. Scalability and robustness stand out as the most critical issues that are to be faced in the implementation of such a simulation. In this paper we present the status of the present simulation and the adopted solutions in terms of speed optimization, centralization of services, framework facilities and persistency solutions. Emphasis is put on the global performance when the different detector components are collected together in a full and detailed simulation. The reference tool adopted is Geant4.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 6 pages. PSN TUMT00

Preferential theory revision

AbstractEmploying a logic program approach, this paper focuses on applying preferential reasoning to theory revision, both by means of preferences among existing theory rules, and by means of preferences on the possible abductive extensions to the theory. And, in particular, how to prefer among plausible abductive explanations justifying observations

ERP evidence for ultra-fast semantic processing in the picture-word interference paradigm

International audienceWe used the event-related potential (ERP) approach combined with a subtraction technique to explore the timecourse of activation of semantic and phonological representations in the picture–word interference paradigm. Subjects were exposed to to-be-named pictures superimposed on to-be-ignored semantically related, phonologically related, or unrelated words, and distinct ERP waveforms were generated time-locked to these different classes of stimuli. Difference ERP waveforms were generated in the semantic condition and in the phonological condition by subtracting ERP activity associated with unrelated picture–word stimuli from ERP activity associated with related picture–word stimuli. We measured both latency and amplitude of these difference ERP waveforms in a pre-articulatory time-window. The behavioral results showed standard interference effects in the semantic condition, and facilitatory effects in the phonological condition. The ERP results indicated a bimodal distribution of semantic effects, characterized by the extremely rapid onset (at about 100 ms) of a primary component followed by a later, distinct, component. Phonological effects in ERPs were characterized by components with later onsets and distinct scalp topography of ERP sources relative to semantic ERP components. Regression analyses revealed a covariation between semantic and phonological behavioral effect sizes and ERP component amplitudes, and no covariation between the behavioral effects and ERP component latency. The early effect of semantic distractors is thought to reflect very fast access to semantic representations from picture stimuli modulating on-going orthographic processing of distractor words

Value-added products from bio-based platform chemicals

This thesis describes the use of platform-derived chemicals as novel, bio-based intermediates to the synthesis of value-added compounds. Levulinic acid-derived angelica lactones were used to preapre C3 chemicals such as malonic acid via ozonolysis and novel poly-norbornene-like polymers. Glycolaldehyde, obtained from lignocellulose, was employed for the first time as C1 building block for the N-formylation of secondary amines by catalyst-free radical oxidation. Methyl vinyl glycolate, a side stream product of the production of lactate from sugars, was used as precursor for bio-based polyester