232 research outputs found

    Performance interface document for users of Tracking and Data Relay Satellite System (TDRSS) electromechanically steered antenna systems (EMSAS)

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    Satellites that use the NASA Tracking and Data Relay Satellite System (TDRSS) require antennas that are crucial for performing and achieving reliable TDRSS link performance at the desired data rate. Technical guidelines are presented to assist the prospective TDRSS medium-and high-data rate user in selecting and procuring a viable, steerable high-gain antenna system. Topics addressed include the antenna gain/transmitter power/data rate relationship; Earth power flux-density limitations; electromechanical requirements dictated by the small beam widths, desired angular coverage, and minimal torque disturbance to the spacecraft; weight and moment considerations; mechanical, electrical and thermal interfaces; design lifetime failure modes; and handling and storage. Proven designs are cited and space-qualified assemblies and components are identified

    Observing Long Colour Flux Tubes in SU(2) Lattice Gauge Theory

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    We present results of a high statistics study of the chromo field distribution between static quarks in SU(2) gauge theory on lattices of volumes 16^4, 32^4, and 48^3*64, with physical extent ranging from 1.3 fm up to 2.7 fm at beta=2.5, beta=2.635, and beta=2.74. We establish string formation over physical distances as large as 2 fm. The results are tested against Michael's sum rules. A detailed investigation of the transverse action and energy flux tube profiles is provided. As a by-product, we obtain the static lattice potential in unpreceded accuracy.Comment: 66 pages, 29 figures, uuencoded latex file with epsfigures (450 K), supplementary full colour figures are available via ftp, CERN-TH.7413/94 (extended version

    PSNCBAM-1 analogs: Structural evolutions and allosteric properties at cannabinoid CB1 receptor

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    Allosteric modulation of the CB1Rs could represent an alternative strategy for the treatment of diseases in which these receptors are involved, without the undesirable effects associated with their orthosteric stimulation. PSNCBAM-1 is a reference diaryl urea derivative that positively affects the binding affinity of orthosteric ligands (PAM) and negatively affects the functional activity of orthosteric ligands (NAM) at CB1Rs. In this work we reported the design, synthesis and biological evaluation of three different series of compounds, derived from structural modifications of PSNCBAM-1 and its analogs reported in the recent literature. Almost all the new compounds increased the percentage of binding affinity of CP55940 at CB1Rs, showing a PAM profile. When tested alone in the [35S]GTPγS functional assay, only a few derivatives lacked detectable activity, so were tested in the same functional assay in the presence of CP55940. Among these, compounds 11 and 18 proved to be functional NAMs at CB1Rs, dampening the orthosteric agonist-induced receptor functionality by approximately 30%. The structural features presented in this work provide new CB1R-allosteric modulators (with a profile similar to the reference compound PSNCBAM-1) and an extension of the structure-activity relationships for this type of molecule at CB1Rs

    Efficacy of the cdk4/6 dual inhibitor abemaciclib in egfr-mutated nsclc cell lines with different resistance mechanisms to osimertinib

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    Abemaciclib is an inhibitor of cyclin-dependent kinases (CDK) 4 and 6 that inhibits the transition from the G1 to the S phase of the cell cycle by blocking downstream CDK4/6-mediated phosphorylation of Rb. The effects of abemaciclib alone or combined with the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib were examined in a panel of PC9 and HCC827 osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines carrying EGFR-dependent or-independent mechanisms of intrinsic or acquired resistance. Differently from sensitive cells, all the resistant cell lines analyzed maintained p-Rb, which may be considered as a biomarker of osimertinib resistance and a potential target for therapeutic intervention. In these models, abemaciclib inhibited cell growth, spheroid formation, colony formation, and induced senes-cence, and its efficacy was not enhanced in the presence of osimertinib. Interestingly, in osimertinib sensitive PC9, PC9T790M, and H1975 cells the combination of abemaciclib with osimertinib significantly inhibited the onset of resistance in long-term experiments. Our findings provide a preclinical support for using abemaciclib to treat resistance in EGFR mutated NSCLC patients progressed to osimertinib either as single treatment or combined with osimertinib, and suggest the combination of osimertinib with abemaciclib as a potential approach to prevent or delay osimertinib resistance in first-line treatment

    Prisutnost Candida sp. u svježem voćnom soku

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    Fruit juices are popular soft drinks with an important role in human nutrition. Fruit juices are often infested by yeast species that can survive different storage conditions. The aim of this study was to determine the degree of yeast contamination of freshly squeezed juices in three large supermarkets in Zagreb, Croatia. The analysis included 84 juice samples obtained from freshly squeezed orange, lemon, grapefruit, and apples. Their acidity varied between pH 2.1 and pH 4.9. Juice samples were plated directly on Sabouraud 4 % glucose Agar (Merck, 1.05438) and processed according to standardised methods (HRN ISO 7954:2002). Yeasts were isolated in all 84 samples and ranged between 0.005x103 and 23x103 colony forming units per mL (CFU mL-1). The most common yeasts identifi ed using the API 20C AUX yeast kit included Candida guillermondii, C. krusei, C. famata, C. spherica, C. colliculosa, C. albicans, Trichosporon mucoides, Kloeckera spp. and yeast-like fungus Cryptococcus neoformans. C. guillermondii prevailed in 55.95 % of all samples.Voćni su sokovi tekući ekstrakti voća dobiveni cijeđenjem zrelog voća te su vrlo važan čimbenik u svakodnevnoj prehrani ljudi. Najčešće zastupljeni mikroorganizmi u svježem voćnom soku su kvasci koji preživljavaju niske temperature skladištenja. Svrha ovog istraživanja bila je odrediti prisutnost i brojnost kvasaca u svježim voćnim sokovima uzorkovanim u supermarketima na području Republike Hrvatske, odnosno glavnom gradu Zagrebu. Ukupno su uzorkovana i pregledana 84 uzorka svježe iscijeđenih naranči, limuna, grejpfruta i jabuka. pH-vrijednost se kretala od 2.1 do 4.9. Uzorci su nacijepljivani direktno na Sabouraudov agar s 4 % glukoze (Merck, Njemačka) u skladu s propisanom normom HRN ISO 7954:2002. U sva 84 uzorka utvrđena je prisutnost kvasaca u broju od 0.005x103 do 23x103 CFU mL-1. Identifi kacija je provedena testom API 20 C AUX (bioMérieux, 20 210). Najčešće su izolirani sljedeći kvasci: Candida guillermondii, C. krusei, C. famata, C. spherica, C. colliculosa, C. albicans, Trichosporon mucoides, Kloeckera spp. i kvascu slična gljivica Cryptococcus neoformans. U svim uzorcima C. guillermondii bila je najčešće izolirani kvasac (55.95 %)

    Gluon Condensation in Nonperturbative Flow Equations

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    We employ nonperturbative flow equations for an investigation of the effective action in Yang-Mills theories. We compute the effective action Γ[B]\Gamma[B] for constant color magnetic fields BB and examine Savvidy's conjecture of an unstable perturbative vacuum. Our results indicate that the absolute minimum of Γ[B]\Gamma[B] occurs for B=0. Gluon condensation is described by a nonvanishing expectation value of the regularized composite operator FμνFμνF_{\mu\nu}F^{\mu\nu} which agrees with phenomenological estimates.Comment: 64 pages, late

    Relativistic Heavy--Ion Collisions in the Dynamical String--Parton Model

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    We develop and extend the dynamical string parton model. This model, which is based on the salient features of QCD, uses classical Nambu-Got\=o strings with the endpoints identified as partons, an invariant string breaking model of the hadronization process, and interactions described as quark-quark interactions. In this work, the original model is extended to include a phenomenological quantization of the mass of the strings, an analytical technique for treating the incident nucleons as a distribution of string configurations determined by the experimentally measured structure function, the inclusion of the gluonic content of the nucleon through the introduction of purely gluonic strings, and the use of a hard parton-parton interaction taken from perturbative QCD combined with a phenomenological soft interaction. The limited number of parameters in the model are adjusted to e+ee^+e^- and pp --pp data. Utilizing these parameters, the first calculations of the model for pp --AA and AA--AA collisions are presented and found to be in reasonable agreement with a broad set of data.Comment: 26 pages of text with 23 Postscript figures placed in tex

    Using shared needles for subcutaneous inoculation can transmit bluetongue virus mechanically between ruminant hosts

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    Bluetongue virus (BTV) is an economically important arbovirus of ruminants that is transmitted by Culicoides spp. biting midges. BTV infection of ruminants results in a high viraemia, suggesting that repeated sharing of needles between animals could result in its iatrogenic transmission. Studies defining the risk of iatrogenic transmission of blood-borne pathogens by less invasive routes, such as subcutaneous or intradermal inoculations are rare, even though the sharing of needles is common practice for these inoculation routes in the veterinary sector. Here we demonstrate that BTV can be transmitted by needle sharing during subcutaneous inoculation, despite the absence of visible blood contamination of the needles. The incubation period, measured from sharing of needles, to detection of BTV in the recipient sheep or cattle, was substantially longer than has previously been reported after experimental infection of ruminants by either direct inoculation of virus, or through blood feeding by infected Culicoides. Although such mechanical transmission is most likely rare under field condition, these results are likely to influence future advice given in relation to sharing needles during veterinary vaccination campaigns and will also be of interest for the public health sector considering the risk of pathogen transmission during subcutaneous inoculations with re-used needles

    Dual Superconductor Scenario of Confinement: A Systematic Study of Gribov Copy Effects

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    We perform a study of the effects from maximal abelian gauge Gribov copies in the context of the dual superconductor scenario of confinement, on the basis of a novel approach for estimation of systematic uncertainties from incomplete gauge fixing. We present numerical results, in SU(2) lattice gauge theory, using the overrelaxed simulated annealing gauge fixing algorithm. We find abelian and non-abelian string tensions to differ significantly, their ratio being 0.92(4) at BETA = 2.5115. An approximate factorization of the abelian potential into monopole and photon contributions has been confirmed, the former giving rise to the abelian string tension.Comment: 35 pages uucompressed LaTeX with 10 encapsuled postscript figure

    Use of satellite observations for operational oceanography: recent achievements and future prospects

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    The paper gives an overview of the development of satellite oceanography over the past five years focusing on the most relevant issues for operational oceanography. Satellites provide key essential variables to constrain ocean models and/or serve downstream applications. New and improved satellite data sets have been developed and have directly improved the quality of operational products. The status of the satellite constellation for the last five years was, however, not optimal. Review of future missions shows clear progress and new research and development missions with a potentially large impact for operational oceanography should be demonstrated. Improvement of data assimilation techniques and developing synergetic use of high resolution satellite observations are important future priorities
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