1,771 research outputs found
A destressing "deafness" in French?
French is a language in which accent is mandatory on the last syllable of every content word. In contrast, Spanish uses accent to distinguish different lexical items (e.g., b'ebe vs beb'e). Two population of subjects were tested on the same materials to study whether such linguistic differences have an impact on the perceptual capacities of listeners. In Experiment 1, using an ABX paradigm, we find that French Subjects have a surprising deficit compared to Spanish Subjects in making accent distinctions. In Experiment 2, we find that Spanish subjects cannot ignore irrelevant differences in accent in a phoneme-based ABX task, whereas French Subjects have no difficulty at all. In Experiment 3, we replicate the basic French finding, and find that Spanish subjects benefit from redundant accent information even when phonemic information alone is sufficient to perform the task. In our final Experiment 4, we show that French subjects can hear the acoustic correlates of accent; their problem seem to arise at the level of short term memory. Implications for language-specific processing and acquisition are discussed
Where is the length effect? A cross-linguistic study.
Many models of speech production assume that one cannot begin to articulate a word before all its segmental units are inserted into the articulatory plan. Moreover, some of these models assume that segments are serially inserted from left to right. As a consequence, latencies to name words should increase with word length. In a series of five experiments, however, we showed that the time to name a picture or retrieve a word associated with a symbol is not affected by the length of the word. Experiments 1 and 2 used French materials and participants, while Experiments 3, 4 and 5 were conducted with English materials and participants. These results are discussed in relation to current models of speech production, and previous reports of length effects are reevaluated in light of these findings. We conclude that if words are encoded serially, then articulation can start before an entire phonological word has been encoded
Perceptual Constraints in Phonotactic Learning
Structural regularities in language have often been attributed to symbolic or statistical general purpose computations, whereas perceptual factors influencing such generalizations have received less interest. Here, we use phonotactic-like constraints as a case study to ask whether the structural properties of specific perceptual and memory mechanisms may facilitate the acquisition of grammatical-like regularities. Participants learned that the consonants C₁ and C₂ had to come from distinct sets in words of the form C₁VccVC₂ (where the critical consonants were in word edges) but not in words of the form cVC₁C₂Vc (where the critical consonants were in word middles). Control conditions ruled out attentional or psychophysical difficulties in word middles. Participants did, however, learn such regularities in word middles when natural consonant classes were used instead of arbitrary consonant sets. We conclude that positional generalizations may be learned preferentially using edge-based positional codes, but that participants can also use other mechanisms when other linguistic cues are given
Effects of omega-3 fatty acids on arterial stiffness in patients with hypertension: a randomized pilot study.
BackgroundOmega-3 fatty acids prevent cardiovascular disease (CVD) events in patients with myocardial infarction or heart failure. Benefits in patients without overt CVD have not been demonstrated, though most studies did not use treatment doses (3.36 g) of omega-3 fatty acids. Arterial stiffness measured by pulse wave velocity (PWV) predicts CVD events independent of standard risk factors. However, no therapy has been shown to reduce PWV in a blood pressure-independent manner. We assessed the effects of esterified omega-3 fatty acids on PWV and serum markers of inflammation among patients with hypertension.Design and methodsWe performed a prospective, randomized; double-blinded pilot study of omega-3 fatty acids among 62 patients in an urban, safety net hospital. Patients received 3.36 g of omega-3 fatty acids vs. matched placebo daily for 3-months. The principal outcome measure was change in brachial-ankle PWV. Serum inflammatory markers associated with CVD risk were also assessed.ResultsThe majority (71 %) were of Latino ethnicity. After 3-months, mean change in arterial PWV among omega-3 and placebo groups was -97 cm/s vs. -33 cm/s respectively (p = 0.36 for difference, after multivariate adjustment for baseline age, systolic blood pressure, and serum adiponectin). Non-significant reductions in lipoprotein-associated phospholipase A2 (LpPLA2) mass and high sensitivity C-reactive protein (hsCRP) relative to placebo were also observed (p = 0.08, and 0.21, respectively).ConclusionHigh-dose omega-3 fatty acids did not reduce arterial PWV or markers of inflammation among patients within a Latino-predominant population with hypertension.Clinical trial registrationNCT00935766 , registered July 8 2009
Theory of quantum frequency translation of light in optical fiber: application to interference of two photons of different color
We study quantum frequency translation and two-color photon interference
enabled by the Bragg scattering four-wave mixing process in optical fiber.
Using realistic model parameters, we computationally and analytically determine
the Green function and Schmidt modes for cases with various pump-pulse lengths.
These cases can be categorized as either "non-discriminatory" or
"discriminatory" in regards to their propensity to exhibit high-efficiency
translation or high-visibility two-photon interference for many different
shapes of input wave packets or for only a few input wave packets,
respectively. Also, for a particular case, the Schmidt mode set was found to be
nearly equal to a Hermite-Gaussian function set. The methods and results also
apply with little modification to frequency conversion by sum-frequency
conversion in optical crystals
Major flaws in conflict prevention policies towards Africa : the conceptual deficits of international actors’ approaches and how to overcome them
Current thinking on African conflicts suffers from misinterpretations oversimplification, lack of focus, lack of conceptual clarity, state-centrism and lack of vision). The paper analyses a variety of the dominant explanations of major international actors and donors, showing how these frequently do not distinguish with sufficient clarity between the ‘root causes’ of a conflict, its aggravating factors and its triggers. Specifically, a correct assessment of conflict prolonging (or sustaining) factors is of vital importance in Africa’s lingering confrontations. Broader approaches (e.g. “structural stability”) offer a better analytical framework than familiar one-dimensional explanations. Moreover, for explaining and dealing with violent conflicts a shift of attention from the nation-state towards the local and sub-regional level is needed.Aktuelle Analysen afrikanischer Gewaltkonflikte sind häufig voller Fehlinterpretationen (Mangel an Differenzierung, Genauigkeit und konzeptioneller Klarheit, Staatszentriertheit, fehlende mittelfristige Zielvorstellungen). Breitere Ansätze (z. B. das Modell der Strukturellen Stabilität) könnten die Grundlage für bessere Analyseraster und Politiken sein als eindimensionale Erklärungen. häufig differenzieren Erklärungsansätze nicht mit ausreichender Klarheit zwischen Ursachen, verschärfenden und auslösenden Faktoren. Insbesondere die richtige Einordnung konfliktverlängernder Faktoren ist in den jahrzehntelangen gewaltsamen Auseinandersetzungen in Afrika von zentraler Bedeutung. Das Diskussionspapier stellt die große Variationsbreite dominanter Erklärungsmuster der wichtigsten internationalen Geber und Akteure gegenüber und fordert einen Perspektivenwechsel zum Einbezug der lokalen und der subregionalen Ebene für die Erklärung und Bearbeitung gewaltsamer Konflikte
Owl and Lizard: Patterns of Head Pose and Eye Pose in Driver Gaze Classification
Accurate, robust, inexpensive gaze tracking in the car can help keep a driver
safe by facilitating the more effective study of how to improve (1) vehicle
interfaces and (2) the design of future Advanced Driver Assistance Systems. In
this paper, we estimate head pose and eye pose from monocular video using
methods developed extensively in prior work and ask two new interesting
questions. First, how much better can we classify driver gaze using head and
eye pose versus just using head pose? Second, are there individual-specific
gaze strategies that strongly correlate with how much gaze classification
improves with the addition of eye pose information? We answer these questions
by evaluating data drawn from an on-road study of 40 drivers. The main insight
of the paper is conveyed through the analogy of an "owl" and "lizard" which
describes the degree to which the eyes and the head move when shifting gaze.
When the head moves a lot ("owl"), not much classification improvement is
attained by estimating eye pose on top of head pose. On the other hand, when
the head stays still and only the eyes move ("lizard"), classification accuracy
increases significantly from adding in eye pose. We characterize how that
accuracy varies between people, gaze strategies, and gaze regions.Comment: Accepted for Publication in IET Computer Vision. arXiv admin note:
text overlap with arXiv:1507.0476
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Words, rules, and mechanisms of language acquisition
We review recent artificial language learning studies, especially those following Endress and Bonatti (2007), suggesting that humans can deploy a variety of learning mechanisms to acquire artificial languages. Several experiments provide evidence for multiple learning mechanisms that can be deployed in fluent speech: one mechanism encodes the positions of syllables within words and can be used to extract generalization, while the other registers co-occurrence statistics of syllables and can be used to break a continuum into its components. We review dissociations between these mechanisms and their potential role in language acquisition. We then turn to recent criticisms of the multiple mechanisms hypothesis and show that they are inconsistent with the available data. Our results suggest that artificial and natural language learning is best understood by dissecting the underlying specialized learning abilities, and that these data provide a rare opportunity to link important language phenomena to basic psychological mechanisms
The Quantum Modular Group in (2+1)-Dimensional Gravity
The role of the modular group in the holonomy representation of
(2+1)-dimensional quantum gravity is studied. This representation can be viewed
as a "Heisenberg picture", and for simple topologies, the transformation to the
ADM "Schr{\"o}dinger picture" may be found. For spacetimes with the spatial
topology of a torus, this transformation and an explicit operator
representation of the mapping class group are constructed. It is shown that the
quantum modular group splits the holonomy representation Hilbert space into
physically equivalent orthogonal ``fundamental regions'' that are interchanged
by modular transformations.Comment: 23 pages, LaTeX, no figures; minor changes and clarifications in
response to referee (basic argument and conclusions unaffected
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