Spurious Shell Closures in the Relativistic Mean Field Model

Following a systematic theoretical study of the ground-state properties of over 7000 nuclei from the proton drip line to the neutron drip line in the relativistic mean field model [Prog. Theor. Phys. 113 (2005) 785], which is in fair agreement with existing experimental data, we observe a few spurious shell closures, i.e. proton shell closures at Z=58 and Z=92. These spurious shell closures are found to persist in all the effective forces of the relativistic mean field model, e.g. TMA, NL3, PKDD and DD-ME2.Comment: 3 pages, to appear in Chinese Physics Letter

Projection and ground state correlations made simple

We develop and test efficient approximations to estimate ground state correlations associated with low- and zero-energy modes. The scheme is an extension of the generator-coordinate-method (GCM) within Gaussian overlap approximation (GOA). We show that GOA fails in non-Cartesian topologies and present a topologically correct generalization of GOA (topGOA). An RPA-like correction is derived as the small amplitude limit of topGOA, called topRPA. Using exactly solvable models, the topGOA and topRPA schemes are compared with conventional approaches (GCM-GOA, RPA, Lipkin-Nogami projection) for rotational-vibrational motion and for particle number projection. The results shows that the new schemes perform very well in all regimes of coupling.Comment: RevTex, 12 pages, 7 eps figure

First Experiences with the New Law on DUID in Belgium: Alcohol and Medicines in Drug Negative Cases

Abstract In March 1999 a new law prohibiting driving while impaired by illegal drugs was introduced in Belgium. The legal procedure consists of a) a field impairment test, b) a urine immunoassay for 4 drug groups and c) ultimate proof by plasma analysis (GC-MS with fixed cut-offs). Over about two years the analysis of 896 blood samples revealed the presence of illicit drug(s) above cut-off in 85% of the cases. For the 15% "false positives" (failed impairment test and positive urine assay without confirmation in plasma) we investigated the possible reasons for impaired behavior. The presence of alcohol and psychoactive medication stands for an important number of our 'false positives'. The results adduce arguments for introducing psychotropic medicines in our traffic law. Our findings further suggest that false positive cases can be reduced by minimizing the delay before blood sampling and optimizing sample preservation. Harmonization of the strategy for detection and penalization of impaired drivers (alcohol and/or drugs) is highly recommended. Introduction In March 1999 a new law on driving under the influence of illegal drugs was introduced in Belgium. The legal procedure is a three-step process: a) a field impairment test, i.e. the assessment of external signs of the presence of drugs by a standardized test battery, b) an onsite immunoassay for amphetamines, cannabinoids, cocaine metabolites or opiates in urine and c) blood sampling for plasma GC/MS analysis with the following analytical cut-offs: THC (tetrahydrocannabinol) 2 ng/mL, free morphine 20 ng/mL, amphetamine, MDMA (ecstasy), MDEA, MBDB, benzoylecgonine (BE) or cocaine 50 ng/mL. The urine test resp. the plasma analysis are performed on the condition that the driver fails the preceding test(s) (1,2). In 2000-2001 the analysis of 896 blood samples revealed the presence of one or more illicit drug(s) above cut-off in 85% of the cases (2). We investigated the 15% 'false positives', i.e. cases where the driver failed the field impairment test and the urine immunoassay test was positive for at least one drug group, but where the plasma GC-MS analysis revealed no prohibited drug above cut-off. In such cases the full legal procedure for driving under the influence of illicit drugs was completed but the driver was not fined or penalized

Using sea cucumbers to illustrate the basics of zoological nomenclature

In addition to a brief account of the need to have unique and unambiguous scientific names for taxa, this paper, annotated with examples of sea cucumbers, explains the basics of zoological nomenclature. In doing so it aims to reduce the confusion that exists among various breeds of end-users of taxonomists who may not fully understand the seemingly arbitrary and often volatile nature of scientific names. This paper also aims to provide teachers and students with a comprehensible account of the basic principles of zoological nomenclature

Using XDAQ in Application Scenarios of the CMS Experiment

XDAQ is a generic data acquisition software environment that emerged from a rich set of of use-cases encountered in the CMS experiment. They cover not the deployment for multiple sub-detectors and the operation of different processing and networking equipment as well as a distributed collaboration of users with different needs. The use of the software in various application scenarios demonstrated the viability of the approach. We discuss two applications, the tracker local DAQ system for front-end commissioning and the muon chamber validation system. The description is completed by a brief overview of XDAQ.Comment: Conference CHEP 2003 (Computing in High Energy and Nuclear Physics, La Jolla, CA

The CMS Event Builder

The data acquisition system of the CMS experiment at the Large Hadron Collider will employ an event builder which will combine data from about 500 data sources into full events at an aggregate throughput of 100 GByte/s. Several architectures and switch technologies have been evaluated for the DAQ Technical Design Report by measurements with test benches and by simulation. This paper describes studies of an EVB test-bench based on 64 PCs acting as data sources and data consumers and employing both Gigabit Ethernet and Myrinet technologies as the interconnect. In the case of Ethernet, protocols based on Layer-2 frames and on TCP/IP are evaluated. Results from ongoing studies, including measurements on throughput and scaling are presented. The architecture of the baseline CMS event builder will be outlined. The event builder is organised into two stages with intelligent buffers in between. The first stage contains 64 switches performing a first level of data concentration by building super-fragments from fragments of 8 data sources. The second stage combines the 64 super-fragments into full events. This architecture allows installation of the second stage of the event builder in steps, with the overall throughput scaling linearly with the number of switches in the second stage. Possible implementations of the components of the event builder are discussed and the expected performance of the full event builder is outlined.Comment: Conference CHEP0

Garvey-Kelson Relations for Nuclear Charge Radii

The Garvey-Kelson relations (GKRs) are algebraic expressions originally developed to predict nuclear masses. In this letter we show that the GKRs provide a fruitful framework for the prediction of other physical observables that also display a slowly-varying dynamics. Based on this concept, we extend the GKRs to the study of nuclear charge radii. The GKRs are tested on 455 out of the approximately 800 nuclei whose charge radius is experimentally known. We find a rms deviation between the GK predictions and the experimental values of only 0.01 fm. This should be contrasted against some of the most successful microscopic models that yield rms deviations almost three times as large. Predictions - with reliable uncertainties - are provided for 116 nuclei whose charge radius is presently unknown.Comment: 4 pages and 3 figure

Readout system test benches

We propose to develop and exploit versatile multi-purpose Personal Computer-based Test Benches to support the evaluation and design of the basic elements required for digital front-end readout and data transmission systems for an LHC experiment. These test benches will have modular hardware facilities for the operation of new readout system components under realistic conditions, and will implement advanced modern software engineering concepts. They will support components such as fast ADCs, hybrid fibre-optic transceivers, and the prototype VLSI systolic array and data-flow processors currently being developed in national research laboratories and by the emerging European HDTV industry. These efforts would also lay the foundations for projects involving the development of custom-designed VLSI circuits