The impact of working memory load on task execution and online plan adjustment during multitasking in a virtual environment

Three experiments investigated the impact of working memory load on online plan adjustment during a test of multitasking in young, nonexpert, adult participants. Multitasking was assessed using the Edinburgh Virtual Errands Test (EVET). Participants were asked to memorize either good or poor plans for performing multiple errands and were assessed both on task completion and on the extent to which they modified their plans during EVET performance. EVET was performed twice, with and without a secondary task loading a component of working memory. In Experiment 1, articulatory suppression was used to load the phonological loop. In Experiment 2, oral random generation was used to load executive functions. In Experiment 3, spatial working memory was loaded with an auditory spatial localization task. EVET performance for both good- and poor-planning groups was disrupted by random generation and sound localization, but not by articulatory suppression. Additionally, people given a poor plan were able to overcome this initial disadvantage by modifying their plans online. It was concluded that, in addition to executive functions, multiple errands performance draws heavily on spatial, but not verbal, working memory resources but can be successfully completed on the basis of modifying plans online, despite a secondary task load

Observation of a Coherence Length Effect in Exclusive Rho^0 Electroproduction

Exclusive incoherent electroproduction of the rho^0(770) meson from 1H, 2H, 3He, and 14N targets has been studied by the HERMES experiment at squared four-momentum transfer Q**2>0.4 GeV**2 and positron energy loss nu from 9 to 20 GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the nuclear transparency, was found to decrease with increasing coherence length of quark-antiquark fluctuations of the virtual photon. The data provide clear evidence of the interaction of the quark- antiquark fluctuations with the nuclear medium.Comment: RevTeX, 5 pages, 3 figure

Determination of the Deep Inelastic Contribution to the Generalised Gerasimov-Drell-Hearn Integral for the Proton and Neutron

The virtual photon absorption cross section differences [sigma_1/2-sigma_3/2] for the proton and neutron have been determined from measurements of polarised cross section asymmetries in deep inelastic scattering of 27.5 GeV longitudinally polarised positrons from polarised 1H and 3He internal gas targets. The data were collected in the region above the nucleon resonances in the kinematic range nu < 23.5 GeV and 0.8 GeV**2 < Q**2 < 12 GeV**2. For the proton the contribution to the generalised Gerasimov-Drell-Hearn integral was found to be substantial and must be included for an accurate determination of the full integral. Furthermore the data are consistent with a QCD next-to-leading order fit based on previous deep inelastic scattering data. Therefore higher twist effects do not appear significant.Comment: 6 pages, 3 figures, 1 table, revte

Measurement of the Neutron Spin Structure Function g1ng_1^n with a Polarized ^3He Target

Results are reported from the HERMES experiment at HERA on a measurement of the neutron spin structure function $g_1^n(x,Q^2)$ in deep inelastic scattering using 27.5 GeV longitudinally polarized positrons incident on a polarized $^3$He internal gas target. The data cover the kinematic range $0.023<x<0.6$ and $1 (GeV/c)^2 < Q^2 <15 (GeV/c)^2$. The integral $\int_{0.023}^{0.6} g_1^n(x) dx$ evaluated at a fixed $Q^2$ of $2.5 (GeV/c)^2$ is $-0.034\pm 0.013(stat.)\pm 0.005(syst.)$. Assuming Regge behavior at low $x$, the first moment $\Gamma_1^n=\int_0^1 g_1^n(x) dx$ is $-0.037\pm 0.013(stat.)\pm 0.005(syst.)\pm 0.006(extrapol.)$.Comment: 4 pages TEX, text available at http://www.krl.caltech.edu/preprints/OAP.htm

Flavor Decomposition of the Polarized Quark Distributions in the Nucleon from Inclusive and Semi-inclusive Deep-inelastic Scattering

Spin asymmetries of semi-inclusive cross sections for the production of positively and negatively charged hadrons have been measured in deep-inelastic scattering of polarized positrons on polarized hydrogen and 3He targets, in the kinematic range 0.023<x<0.6 and 1 GeV^2<Q^2<10 GeV^2. Polarized quark distributions are extracted as a function of x for up $(u+u_bar) and down (d+d_bar) flavors. The up quark polarization is positive and the down quark polarization is negative in the measured range. The polarization of the sea is compatible with zero. The first moments of the polarized quark distributions are presented. The isospin non-singlet combination Delta_q_3 is consistent with the prediction based on the Bjorken sum rule. The moments of the polarized quark distributions are compared to predictions based on SU(3)_f flavor symmetry and to a prediction from lattice QCD.Comment: 14 pages, 6 figures (eps format), 10 tables in Latex New version contains tables of asymmetries and correlation matri

Solving Games Without Determinization

Abstract The synthesis of reactive systems requires the so-lution of two-player games on graphs with!-regularobjectives. When the objective is specified by a linear temporal logic formula or nondeterministic B&amp;quot;uchi au-tomaton, then previous algorithms for solving the game require the construction of an equivalent deterministicautomaton. However, determinization for automata on infinite words is extremely complicated, and current im-plementations fail to produce deterministic automata even for relatively small inputs. We show how to con-struct, from a given nondeterministic B&amp;quot;uchi automaton, an equivalent nondeterministic parity automaton N that is good for solving games with objective N. Themain insight is that a nondeterministic automaton is good for solving games if it fairly simulates the equiv-alent deterministic automaton. In this way, we omit the determinization step in game solving and reactivesynthesis. The fact that our automata are nondeterministic makes them surprisingly simple, amenable tosymbolic implementation, and allows an incremental search for winning strategies. 1 Introduction One of the most ambitious goals in formal methods isto automatically produce designs from their specifications, a process called synthesis. We are interested inreactive systems, i.e., systems that continuously interact with other programs, users, or their environment(like operating systems or CPUs). The complexity of a reactive system does not arise from computing a com-plicated function but rather from the fact that it has to be able to react to all possible inputs and maintainits behavior forever. There are two (essentially equivalent) approaches to solving the synthesis problem. Thefirst is by reducing it to the emptiness problem of tree automata [27], and the second, by reducing it to solv-ing infinite-duration two-player games [3]. We consider the second view. The two players in the game are thesystem and its environment. The environment tries to violate the specification and the system tries to sat-isfy it. The system wins the game if it has a strategy such that all infinite outcomes satisfy the specification.The winning strategy, the way in which the system updates its internal variables, is then translated into animplementation that satisfies the specification when interacting with any possible environment

Towards a History of Mass Violence in the Etat Indépendant du Congo, 1885-1908

The present article provides an up-to-date scholarly introduction to mass violence in the Etat Indépendant du Congo (Congo Free State, EIC). Its aims are twofold: to offer a point of access to the extensive literature and historical debates on the subject, and to make the case for exchanging the currently prevalent top-down narrative, with its excessive focus on King Leopold's character and motives, for one which considers the EIC's culture of violence as a multicausal, broadly based and deeply engrained social phenomenon. The argument is divided into five sections. Following a general outline of the EIC's violent system of administration, I discuss its social and demographic impact (and the controversy which surrounds it) to bring out the need for more regionally focused and context sensitive studies. The dispute surrounding demographics demonstrates that what is fundamentally at stake is the place the EIC's extreme violence should occupy in the history of European ‘modernity’. Since approaches which hinge on Leopoldian exceptionalism are particularly unhelpful in clarifying this issue, I pause to reflect on how such approaches came to dominate the distinct historiographical traditions which emerged in Belgium and abroad before moving on to a more detailed exploration of a selection of causes underlying the EIC's violent nature. While state actors remain in the limelight, I shift the focus from the state as a singular, normative agent, towards the existence of an extremely violent society in which various individuals and social groups within and outside of the state apparatus committed violent acts for multiple reasons. As this argument is pitched at a high level of abstraction, I conclude with a discussion of available source material with which it can be further refined and updated