Particle Correlations at LEP

Particle correlations are extensively studied to obtain information about the dynamics of hadron production. From 1989 to 2000 the four LEP collaborations recorded more than 16 million hadronic Z0 decays and several thousand W+W- events. In Z0 decays, two-particle correlations were analysed in detail to study Bose-Einstein and Fermi-Dirac correlations for various particle species. In fully-hadronic W+W- decays, particle correlations were used to study whether the two W bosons decay independently. A review of selected results is presented.Comment: To appear in the proceedings of the first High-Energy Physics Conference in Madagascar (HEP-MAD'01), Antananarivo, Madagascar, 27 Sep - 5 Oct 2001 OPAL conference report CR48

Polarization and Spin Alignment in Multihadronic Z0 Decays

The large statistics of millions of hadronic Z0 decays, accumulated by the four LEP experiments between 1989 and 1995, allowed for detailed investigations of the fragmentation process. Inclusive Lambda_b baryons and Lambda hyperons at intermediate and high momentum have been found to show longitudinal polarization. This may be related to the primary quark and antiquark polarization and the hadronization mechanism which produces the leading baryons. Helicity density-matrix elements have been measured for a variety of vector mesons produced inclusively in hadronic Z0 decays. The diagonal elements of some of the light mesons and the D*+- show a preference for a helicity-zero state if the meson carries a large fraction of the available energy. The mechanism which produces such spin alignment in the non-perturbative hadronization of the primary partons to the vector mesons is so far unexplained. For the B* the results are consistent with no spin alignment, which is expected in a picture based on HQET. For some meson species non-diagonal elements have been measured indicating coherence phenomena due to final-state interaction between the primary quark and antiquark.Comment: Jan 2001. 6pp. To be published in the proceedings of 30th International Symposium on Multiparticle Dynamics (ISMD 2000), Tihany, Lake Balaton, Hungary, 9-15 Oct 2000 ;updated version: minor stylistic modifications as suggested by the edito

The tax-inducible actin-bundling protein fascin is crucial for release and cell-to-cell transmission of human T-cell leukemia virus type 1 (HTLV-1)

The delta-retrovirus Human T-cell leukemia virus type 1 (HTLV-1) preferentially infects CD4(+) T-cells via cell-to-cell transmission. Viruses are transmitted by polarized budding and by transfer of viral biofilms at the virological synapse (VS). Formation of the VS requires the viral Tax protein and polarization of the host cytoskeleton, however, molecular mechanisms of HTLV-1 cell-to-cell transmission remain incompletely understood. Recently, we could show Tax-dependent upregulation of the actin-bundling protein Fascin (FSCN-1) in HTLV-1-infected T-cells. Here, we report that Fascin contributes to HTLV-1 transmission. Using single-cycle replication-dependent HTLV-1 reporter vectors, we found that repression of endogenous Fascin by short hairpin RNAs and by Fascin-specific nanobodies impaired gag p19 release and cell-to-cell transmission in 293T cells. In Jurkat T-cells, Tax-induced Fascin expression enhanced virus release and Fascin-dependently augmented cell-to-cell transmission to Raji/CD4(+) B-cells. Repression of Fascin in HTLV-1-infected T-cells diminished virus release and gag p19 transfer to co-cultured T-cells. Spotting the mechanism, flow cytometry and automatic image analysis showed that Tax-induced T-cell conjugate formation occurred Fascin-independently. However, adhesion of HTLV-1-infected MT-2 cells in co-culture with Jurkat T-cells was reduced upon knockdown of Fascin, suggesting that Fascin contributes to dissemination of infected T-cells. Imaging of chronically infected MS9 T-cells in co-culture with Jurkat T-cells revealed that Fascin's localization at tight cell-cell contacts is accompanied by gag polarization suggesting that Fascin directly affects the distribution of gag to budding sites, and therefore, indirectly viral transmission. In detail, we found gag clusters that are interspersed with Fascin clusters, suggesting that Fascin makes room for gag in viral biofilms. Moreover, we observed short, Fascin-containing membrane extensions surrounding gag clusters and clutching uninfected T-cells. Finally, we detected Fascin and gag in long-distance cellular protrusions. Taken together, we show for the first time that HTLV-1 usurps the host cell factor Fascin to foster virus release and cell-to-cell transmission

OddzOn Products and Derivation of Invention: At Odds with the Purpose of Section 102(f) of the Patent Act of 1952?

Abstract Background Antimicrobial peptides are important components of the host defence with a broad range of functions including direct antimicrobial activity and modulation of inflammation. Lack of cathelin-related antimicrobial peptide (CRAMP) was associated with higher mortality and bacterial burden and impaired neutrophil granulocyte infiltration in a model of pneumococcal meningitis. The present study was designed to characterize the effects of CRAMP deficiency on glial response and phagocytosis after exposure to bacterial stimuli. Methods CRAMP-knock out and wildtype glial cells were exposed to bacterial supernatants from Streptococcus pneumoniae and Neisseria meningitides or the bacterial cell wall components lipopolysaccharide and peptidoglycan. Cell viability, expression of pro- and anti-inflammatory mediators and activation of signal transduction pathways, phagocytosis rate and glial cell phenotype were investigated by means of cell viability assays, immunohistochemistry, real-time RT-PCR and Western blot. Results CRAMP-deficiency was associated with stronger expression of pro-inflammatory and weakened expression of anti-inflammatory cytokines indicating a higher degree of glial cell activation even under resting-state conditions. Furthermore, increased translocation of nuclear factor ‘kappa-light-chain-enhancer’ of activated B-cells was observed and phagocytosis of S. pneumoniae was reduced in CRAMP-deficient microglia indicating impaired antimicrobial activity. Conclusions In conclusion, the present study detected severe alterations of the glial immune response due to lack of CRAMP. The results indicate the importance of CRAMP to maintain and regulate the delicate balance between beneficial and harmful immune response in the brain

Baysian uncertainty quantification and calibration of a clean-coal design code

Current concerns about atmospheric carbon levels have sparked demands for massively reduced carbon emissions. These demands, both environmental and regulatory, exceed the capacity for near-term deployment of emission free technologies. Therefore, to simultaneously meet carbon emission targets and supply the vast global energy demands in the foreseeable future, energy generation must incorporate carbon-capture and sequestration technologies on point source CO­2 emitters such as coal-fired power plants. Coal-fired power plants have long been the primary energy pillar of industrialized nations, and while reduced utilization is an important target for CO2 reduction, coal combustion remains the most intensive and prevalent point emission source, and represents hundreds of billions of dollars globally in infrastructure that cannot easily be abandoned. As such, it is the most important target for carbon-capture technologies, particularly retrofit technologies that could allow for near-term, relatively rapid deployment in current infrastructure. The present work supports near-term deployment of oxy-coal combustion as a CO2 capture strategy through computer modeling for both retrofitted boilers and new construction. Oxy-coal combustion is a clean coal technology that uses either a high purity O2 stream, or a mixture of O2 and recycled flue gas to burn coal and produce a CO2 emission stream for capture without the need for post-combustion separation. This combustion environment is a radical departure from the air-fired pulverized coal boiler. Exa-scale Computational Fluid Dynamics (CFD) modeling codes enable relatively low-cost, rapid design in this new environment; however, they depend on physically accurate and predictive sub-models. The present work improves the predictive capacity and quantifies the uncertainty of the Carbon Conversion Kinetics oxy-fuel (CCK/oxy) code, a comprehensive coal char conversion model designed to predict coal char burnout in the intense oxy-fuel environment. A recent sensitivity analysis of the CCK/oxy model strongly implicated the char thermal deactivation routine as a key sub-model to accurately predict char conversion, and the present work uses Bayesian uncertainty quantification and calibration in conjunction with literature data to quantify and reduce the uncertainty in the vital annealing sub-model. The suite of Bayesian statistical tools used here were originally extended to facilitate computational design of CCS technologies. Specifically, the tools used here are based upon GPMSA (Gaussian Process Models for Simulation Analysis), and provide the capability for relatively low-cost calibration, uncertainty quantification, sensitivity analysis, and model response prediction based upon a reasonable number of model executions. We present the results of the calibration using these tools which incorporate the information from both empirical physical measurements and detailed physics-based simulation models. Acknowledgements: The work at LANL is supported by the Carbon Capture Simulation Initiative with funding through the Office of Fossil Energy, US Department of Energy. The work at BYU is supported by the Department of Energy, National Nuclear Security Administration, under Award Number DE-NA0002375

Importance of Tests for the Complete Lorentz Structure of the t --> W+ b vertex at Hadron Colliders

The most general Lorentz-invariant decay-density-matrix for $t\to W^{+}b\to (l^{+}\nu)b$, or for $t\to W^{+}b\to (j_{\bar d}j_u)b$, is expressed in terms of eight helicity parameters. The parameters are physically defined in terms of partial-width-intensities for polarized-final-states in $t\to W^{+}b$ decay. The parameters are the partial width, the $b$ quark's chirality parameter $\xi$, the $W^+$ polarimetry parameter $\sigma$, a "pre-SSB" test parameter $\zeta$, and four $W_{L}$-$W_{T}$ interference parameters $\eta$, $\eta^{'}$, $\omega$, $\omega^{'}$ which test for $\tilde T_{FS}$ violation. They can be used to test for non-CKM-type CP violation, anomalous $\Gamma_{L,T}$'s, top weak magnetism, weak electricity, and second-class currents. By stage-two spin-correlation techniques, percent level statistical uncertainites are typical for measurements at the Tevatron, and several mill level uncertainites are typical at the LHC.Comment: Minor clarifications. Expression for r_{+-} corrected. 19 pages LaTex + Tables + 1 Figur

Application of augmented reality and robotic technology in broadcasting: A survey

As an innovation technique, Augmented Reality (AR) has been gradually deployed in the broadcast, videography and cinematography industries. Virtual graphics generated by AR are dynamic and overlap on the surface of the environment so that the original appearance can be greatly enhanced in comparison with traditional broadcasting. In addition, AR enables broadcasters to interact with augmented virtual 3D models on a broadcasting scene in order to enhance the performance of broadcasting. Recently, advanced robotic technologies have been deployed in a camera shooting system to create a robotic cameraman so that the performance of AR broadcasting could be further improved, which is highlighted in the paper

Variability of the methane trapping in martian subsurface clathrate hydrates

Recent observations have evidenced traces of methane CH4 heterogeneously distributed in the martian atmosphere. However, because the lifetime of CH4 in the atmosphere of Mars is estimated to be around 300-600 years on the basis of photochemistry, its release from a subsurface reservoir or an active primary source of methane have been invoked in the recent literature. Among the existing scenarios, it has been proposed that clathrate hydrates located in the near subsurface of Mars could be at the origin of the small quantities of the detected CH4. Here, we accurately determine the composition of these clathrate hydrates, as a function of temperature and gas phase composition, by using a hybrid statistical thermodynamic model based on experimental data. Compared to other recent works, our model allows us to calculate the composition of clathrate hydrates formed from a more plausible composition of the martian atmosphere by considering its main compounds, i.e. carbon dioxyde, nitrogen and argon, together with methane. Besides, because there is no low temperature restriction in our model, we are able to determine the composition of clathrate hydrates formed at temperatures corresponding to the extreme ones measured in the polar caps. Our results show that methane enriched clathrate hydrates could be stable in the subsurface of Mars only if a primitive CH4-rich atmosphere has existed or if a subsurface source of CH4 has been (or is still) present.Comment: Accepted for publication in Planetary and Space Scienc