2,673 research outputs found

    Contrast coding choices in a decade of mixed models

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    Contrast coding in regression models, including mixed-effect models, changes what the terms in the model mean. In particular, it determines whether or not model terms should be interpreted as main effects. This paper highlights how opaque descriptions of contrast coding have affected the field of psycholinguistics. We begin with a reproducible example in R using simulated data to demonstrate how incorrect conclusions can be made from mixed models; this also serves as a primer on contrast coding for statistical novices. We then present an analysis of 3384 papers from the field of psycholinguistics that we coded based upon whether a clear description of contrast coding was present. This analysis demonstrates that the majority of the psycholinguistic literature does not transparently describe contrast coding choices, posing an important challenge to reproducibility and replicability in our field

    PIPS: A parallel planning model of sentence production

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    Subject–verb agreement errors are common in sentence production. Many studies have used experimental paradigms targeting the production of subject–verb agreement from a sentence preamble (The key to the cabinets) and eliciting verb errors (… *were shiny). Through reanalysis of previous data (50 experiments; 102,369 observations), we show that this paradigm also results in many errors in preamble repetition, particularly of local noun number (The key to the *cabinet). We explore the mechanisms of both errors in parallelism in producing syntax (PIPS), a model in the Gradient Symbolic Computation framework. PIPS models sentence production using a continuous-state stochastic dynamical system that optimizes grammatical constraints (shaped by previous experience) over vector representations of symbolic structures. At intermediate stages in the computation, grammatical constraints allow multiple competing parses to be partially activated, resulting in stable but transient conjunctive blend states. In the context of the preamble completion task, memory constraints reduce the strength of the target structure, allowing for co-activation of non-target parses where the local noun controls the verb (notional agreement and locally agreeing relative clauses) and non-target parses that include structural constituents with contrasting number specifications (e.g., plural instead of singular local noun). Simulations of the preamble completion task reveal that these partially activated non-target parses, as well the need to balance accurate encoding of lexical and syntactic aspects of the prompt, result in errors. In other words: Because sentence processing is embedded in a processor with finite memory and prior experience with production, interference from non-target production plans causes errors

    Interviewing suspects: examining the association between skills, questioning, evidence disclosure, and interview outcomes

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    The interviewing of suspects is an important element in the investigation of crime. However, studies concerning actual performance of investigators when undertaking such interviews remain sparse. Nevertheless, in England and Wales, since the introduction of a prescribed framework over 20 years ago, field studies have generally shown an improvement in interviewing performance, notwithstanding ongoing concerns largely relating to the more demanding aspects (such as building/maintaining rapport, intermittent summarising and the logical development of topics). Using a sample of 70 real-life interviews, the present study examined questioning and various evidence disclosure strategies (which have also been found demanding), examining their relationships between interview skills and interview outcomes. It was found that when evidence was disclosed gradually (but revealed later), interviews were generally both more skilled and involved the gaining of comprehensive accounts, whereas when evidence was disclosed either early or very late, interviews were found to be both less skilled and less likely to involve this outcome. These findings contribute towards an increased research base for the prescribed framework

    Insertion polymorphism of retrotransposable elements in populations of the insular, endemic species Drosophila madeirensis

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    The insertion site numbers of the retrotransposable elements (TE) 412, gypsy and bilbo were determined in individuals of five distinct natural populations of the endemic species Drosophila madeirensis from the island of Madeira. The TE distributions were compared to those of the paleartic, widespread and phylogenetically closely related species, D. subobscura. In situ hybridization and Southern blots showed that in D. madeirensis the number of insertion sites ranged between 10 and 15, three and six, and 35 and 42 for elements 412, gypsy and bilbo, respectively. The corresponding values for D. subobscura were similar. Two of these elements, 412 and gypsy, had very few insertions in the heterochromatin, unlike bilbo, which displayed a high heterochromatic insertion number. The Southern band polymorphism was very high, leading to within-population variation of 97.2%, whatever the population and the TE concerned. Using the polymorphic TE insertion sites as markers to analyse population structure by AMOVA, adapted for RAPD (Randomly Amplified Polymorphic DNA) data, we found small but significant genetic differences between the populations on Madeira. This slight differentiation, coupled with similar copy numbers for each TE between populations, suggests that the D. madeirensis species consists of a single, only slightly subdivided population. These data also show that insular populations and endemic species of Drosophila can have as many copies of TEs as more widespread species.info:eu-repo/semantics/publishedVersio

    What CIOs and CTOs Need to Know About Big Data and Data-Intensive Computing

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    This paper was completed as part of the final research component in the University of Oregon Applied Information Management Master's Degree Program [see htpp://aim.uoregon.edu].The nature of business computing is changing due to the proliferation of massive data sets referred to as big data, that can be used to produce business analytics (Borkar, Carey, & Li, 2012). This annotated bibliography presents literature published between 2000 and 2012. It provides information to CIOs and CTOs about big data by: (a) identifying business examples, (b) describing the relationship to data-intensive computing, (c) exploring opportunities and limitations, and (d) identifying cost factors

    Triangulations and Severi varieties

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    We consider the problem of constructing triangulations of projective planes over Hurwitz algebras with minimal numbers of vertices. We observe that the numbers of faces of each dimension must be equal to the dimensions of certain representations of the automorphism groups of the corresponding Severi varieties. We construct a complex involving these representations, which should be considered as a geometric version of the (putative) triangulations

    Mid-infrared frequency comb spanning an octave based on an Er fiber laser and difference-frequency generation

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    We describe a coherent mid-infrared continuum source with 700 cm-1 usable bandwidth, readily tuned within 600 - 2500 cm-1 (4 - 17 \mum) and thus covering much of the infrared "fingerprint" molecular vibration region. It is based on nonlinear frequency conversion in GaSe using a compact commercial 100-fs-pulsed Er fiber laser system providing two amplified near-infrared beams, one of them broadened by a nonlinear optical fiber. The resulting collimated mid-infrared continuum beam of 1 mW quasi-cw power represents a coherent infrared frequency comb with zero carrier-envelope phase, containing about 500,000 modes that are exact multiples of the pulse repetition rate of 40 MHz. The beam's diffraction-limited performance enables long-distance spectroscopic probing as well as maximal focusability for classical and ultraresolving near-field microscopies. Applications are foreseen also in studies of transient chemical phenomena even at ultrafast pump-probe scale, and in high-resolution gas spectroscopy for e.g. breath analysis.Comment: 8 pages, 2 figures revised version, added reference
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