130 research outputs found

    HATS Abstract Behavioral Specification: The Architectural View

    Full text link
    The Abstract Behavioral Specification (ABS) language is a formal, executable, object-oriented, concurrent modeling language intended for behavioral modeling of complex software systems that exhibit a high degree of variation, such as software product lines. We give an overview of the architectural aspects of ABS: a feature-driven development workflow, a formal notion of deployment components for specifying environmental constraints, and a dynamic component model that is integrated into the language. We employ an industrial case study to demonstrate how the various aspects work together in practic

    Diffusion and Innovation Theory: Past, Present, and Future Contributions to Academia and Practice

    Get PDF
    Part 4: PanelInternational audienceThe field of information systems (IS) has throughout its history experienced extensive changes in technology, research, and education. These renewals will continue into the foreseeable future [10]. It is recognized that IS is a key force in the ongoing societal and organizational renewal and change [2, 8, 14]. For example, in the US business sector, IS continues yearly to consume about 30% of total investments made [5]. Recent research document that IS supports the creation of business value, with particular emphasis on an organization’s innovation and change capabilities [1, 3]. Traditionally, research in IS has been interdisciplinary in nature - since it draws on innovation theory, models of value creation, actors’ roles and behaviors, the creation and running of task oriented groups, and how these relate to organizational structures and mechanisms [24]. Throughout its history the question of benefits from investing in IS has been lively discussed

    The covalent reactivity of functionalized 5-hydroxy-butyrolactams is the basis for targeting of fatty acid binding protein 5 (FABP5) by the neurotrophic agent MT-21

    Get PDF
    Covalently acting compounds experience a strong interest within chemical biology both as molecular probes in studies of fundamental biological mechanisms and/or as novel drug candidates. In this context, the identification of new classes of reactive groups is particularly important as these can expose novel reactivity modes and, consequently, expand the ligandable proteome. Here, we investigated the electrophilic reactivity of the 3-acyl-5-hydroxy-1,5-dihydro-2H-pyrrole-2-one (AHPO) scaffold, a heterocyclic motif that is e.g. present in various bioactive natural products. Our investigations were focused on the compound MT-21 - a simplified structural analogue of the natural product epolactaene - which is known to have both neurotrophic activity and ability to trigger apoptotic cell death. We found that the central N-acyl hemiaminal group of MT-21 can function as an electrophilic centre enabling divergent reactivity with both amine- and thiokbased nucleophiles, which furthermore translated to reactivity with proteins in both cell lysates and live cells. We found that in live cells MT-21 strongly engaged the lipid transport protein fatty acid-binding protein 5 (FABP5) by direct binding to a cysteine residue in the bottom of the ligand binding pocket. Through preparation of a series of MT-21 derivatives, we probed the specificity of this interaction which was found to be strongly dependent on subtle structural changes. Our study suggests that MT-21 may be employed as a tool compound in future studies of the biology of FABP5, which remains incompletely understood. Furthermore, our study has also made dear that other natural products containing the AHPO-motif may likewise possess covalent reactivity and that this property may underlie their biological activity.Molecular Physiolog

    On Some New Black String Solutions in Three Dimensions

    Get PDF
    We derive several new solutions in three-dimensional stringy gravity. The solutions are obtained with the help of string duality transformations. They represent stationary configurations with horizons, and are surrounded by (quasi) topologically massive Abelian gauge hair, in addition to the dilaton and the Kalb-Ramond axion. Our analysis suggests that there exists a more general family, where our solutions are special limits. Finally, we use the generating technique recently proposed by Garfinkle to construct a traveling wave on the extremal variant of one of our solutions.Comment: revtex, 38 pages including 3 figure

    UHECR as Decay Products of Heavy Relics? The Lifetime Problem

    Full text link
    The essential features underlying the top-down scenarii for UHECR are discussed, namely, the stability (or lifetime) imposed to the heavy objects (particles) whatever they be: topological and non-topological solitons, X-particles, cosmic defects, microscopic black-holes, fundamental strings. We provide an unified formula for the quantum decay rate of all these objects as well as the particle decays in the standard model. The key point in the top-down scenarii is the necessity to adjust the lifetime of the heavy object to the age of the universe. This ad-hoc requirement needs a very high dimensional operator to govern its decay and/or an extremely small coupling constant. The natural lifetimes of such heavy objects are, however, microscopic times associated to the GUT energy scale (sim 10^{-28} sec. or shorter). It is at this energy scale (by the end of inflation) where they could have been abundantly formed in the early universe and it seems natural that they decayed shortly after being formed.Comment: 11 pages, LaTex, no figures, updated versio

    Production of Mesons and Baryons at High Rapidity and High Pt in Proton-Proton Collisions at s\sqrt{s} = 200 GeV

    Get PDF
    We present particle spectra for charged hadrons π±,K±,p\pi^\pm, K^\pm, p and pˉ\bar{p} from pp collisions at s\sqrt{s}=200GeVmeasuredforthefirsttimeatforwardrapidities(2.95and3.3).Thekinematicsofthesemeasurementsareskewedinawaythatprobesthesmallmomentumfractioninoneoftheprotonsandlargefractionsintheother.Largeprotontopionratiosareobservedatvaluesoftransversemomentumthatextendupto4GeV/c,whereprotonshavemomentaupto35GeV.NexttoleadingorderperturbativeQCDcalculationsdescribetheproductionofpionsandkaonswellattheserapidities,butfailtoaccountforthelargeprotonyieldsandsmall GeV measured for the first time at forward rapidities (2.95 and 3.3). The kinematics of these measurements are skewed in a way that probes the small momentum fraction in one of the protons and large fractions in the other. Large proton to pion ratios are observed at values of transverse momentum that extend up to 4 GeV/c, where protons have momenta up to 35 GeV. Next-to-leading order perturbative QCD calculations describe the production of pions and kaons well at these rapidities, but fail to account for the large proton yields and small \bar{p}/p$ ratios associated with baryon transport

    Nuclear stopping and rapidity loss in Au+Au collisions at sqrt{s_{NN}}=62.4 GeV

    Get PDF
    Transverse momentum spectra of protons and anti-protons measured in the rapidity range 0<y<3.1 from 0-10% central Au+Au collisions at sqrt{s_{NN}}=62.4 GeV are presented. The rapidity densities, dN/dy, of protons, anti-protons and net-protons N()p-N(pbar) have been deduced from the spectra over a rapidity range wide enough to observe the expected maximum net-baryon density. From mid-rapidity to y=1 the net-proton yield is roughly constant (dN/dy ~ 10),but rises to dN/dy ~25 at 2.3<y<3.1. The mean rapidity loss is 2.01 +-0.16 units from beam rapidity. The measured rapidity distributions are compared to model predictions. Systematics of net-baryon distributions and rapidity loss vs. collision energy are discussed.Comment: 5 pages, 5 figures. Submitted Phys.Lett.

    Kaon and Pion Production in Central Au+Au Collisions at \sqrt{s_{NN}}=62.4 GeV

    Full text link
    Invariant pT spectra and rapidity densities covering a large rapidity range(-0.1 < y < 3.5) are presented for π±\pi^{\pm} and K±K^{\pm} mesons from central Au+Au collisions at sNN\sqrt{s_{NN}} = 62.4 GeV. The mid-rapidity yields of meson particles relative to their anti-particles are found to be close to unity (π/π+1\pi^-/\pi^+ \sim 1, K/K+0.85K^-/K^+ \sim 0.85) while the anti-proton to proton ratio is pˉ/p0.49\bar{p}/p \sim 0.49. The rapidity dependence of the π/π+\pi^-/\pi^+ ratio is consistent with a small increase towards forward rapidities while the K/K+K^-/K^+ and pˉ/p\bar{p}/p ratios show a steep decrease to \sim 0.3 for kaons and 0.022 for protons at y3y\sim 3. It is observed that the kaon production relative to its own anti-particle as well as to pion production in wide rapidity and energy ranges shows an apparent universal behavior consistent with the baryo-chemical potential, as deduced from the pˉ/p\bar{p}/p ratio, being the driving parameter.Comment: Submitted to PLB, 6 journal pages, 7 figure
    corecore