2,976 research outputs found
The effect of aging on cervical parameters in a normative North American population
Study Design: Retrospective cohort study. Objectives: To investigate age-based changes in cervical alignment parameters in an asymptomatic population. Methods: Retrospective review of a prospective study of 118 asymptomatic subjects who underwent biplanar imaging with 3-dimensional capabilities. Demographic and health-related quality of life data was collected prior to imaging. Patients were stratified into 5 age groups: <35 years, 35-44 years, 45-54 years, 55-64 years, and ≥65 years. Radiographic measurements of the cervical spine and spinopelvic parameters were compared between age groups. The normal distribution of parameters was assessed followed by analysis of variance for comparison of variance between age groups. Results: C2-C7 lordosis, C0-C7 lordosis, and T1 slope demonstrated significant increases with age. C0-C7 lordosis was significantly less in subjects <35 years compared with ≥55 years. Significant differences in T1 slope were identified in patients <35 versus ≥65, 35-44 versus ≥65, and 45-54 versus ≥65 years. T1 slope demonstrated a positive correlation with age. Horizontal gaze parameters did not change linearly with age and mean averages of all age groups were within 10° of one another. Cervical kyphosis was present in approximately half of subjects who were <55 compared with approximately 10% of subjects ≥55 years. Differences in pelvic tilt, pelvic incidence-lumbar lordosis, and C7-S1 sagittal vertical axis were identified with age. Conclusions: C0-C7 lordosis, C2-C7 lordosis, and T1 slope demonstrate age-based changes while other cervical and horizontal gaze parameters remain relatively constant with age. </jats:sec
Phonetic variability and grammatical knowledge: an articulatory study of Korean place assimilation.
The study reported here uses articulatory data to investigate Korean place assimilation
of coronal stops followed by labial or velar stops, both within words and
across words. The results show that this place-assimilation process is highly
variable, both within and across speakers, and is also sensitive to factors such as the
place of articulation of the following consonant, the presence of a word boundary
and, to some extent, speech rate. Gestures affected by the process are generally
reduced categorically (deleted), while sporadic gradient reduction of gestures is
also observed. We further compare the results for coronals to our previous findings
on the assimilation of labials, discussing implications of the results for grammatical
models of phonological/phonetic competence. The results suggest that speakers’
language-particular knowledge of place assimilation has to be relatively
detailed and context-sensitive, and has to encode systematic regularities about its
obligatory/variable application as well as categorical/gradient realisation
"Irregular" Verbs in Korean Revisited
A number of Korean verbs 1 do not follow the general phonological rules in their conjugation. However, the patternedness of their "irregularity" has long been noted by most grammarians. Thus even the earliest analyses set up different "classes" of "irregular" verbs (Choy 1937- 1971, Martin 1954, He 1965- 1972, C-W Kim 1967)2. Furthermore it was well known that many of the irregularities were due to some earlier historical processes. More recently in applying the generative theory, many linguists (C-W Kim 1970, Chag-yun Kim 1971, Lee 1973, Cook 1973) have come to believe that most, if not all, of these "anomalous" verbs are not really exceptions to some fixed rules but that they behave differently because they have different underlying forms. Thus superficially identical forms of "regular" and "irregular" verbs are thought to be a direct result of certain phonological rules which neutralize them in a well-defined environment. This paper purports to review some of the "regular" solutions thus far given and to present my own claim on the underlying representations of the "irregular" verbs and the phonlogical rules required to derive their phonetic representations. Choy(l937-71) gives twelve classes of verbs which show anomaly either in the shape of their stems or in the affixes that are attached to them. I shall group them into five sections in each of which related processes will be discussed
Self-similar correlation function in brain resting-state fMRI
Adaptive behavior, cognition and emotion are the result of a bewildering
variety of brain spatiotemporal activity patterns. An important problem in
neuroscience is to understand the mechanism by which the human brain's 100
billion neurons and 100 trillion synapses manage to produce this large
repertoire of cortical configurations in a flexible manner. In addition, it is
recognized that temporal correlations across such configurations cannot be
arbitrary, but they need to meet two conflicting demands: while diverse
cortical areas should remain functionally segregated from each other, they must
still perform as a collective, i.e., they are functionally integrated. Here, we
investigate these large-scale dynamical properties by inspecting the character
of the spatiotemporal correlations of brain resting-state activity. In physical
systems, these correlations in space and time are captured by measuring the
correlation coefficient between a signal recorded at two different points in
space at two different times. We show that this two-point correlation function
extracted from resting-state fMRI data exhibits self-similarity in space and
time. In space, self-similarity is revealed by considering three successive
spatial coarse-graining steps while in time it is revealed by the 1/f frequency
behavior of the power spectrum. The uncovered dynamical self-similarity implies
that the brain is spontaneously at a continuously changing (in space and time)
intermediate state between two extremes, one of excessive cortical integration
and the other of complete segregation. This dynamical property may be seen as
an important marker of brain well-being both in health and disease.Comment: 14 pages 13 figures; published online before print September 2
Exploring Consumers’ Attitudes of Smart TV Related Privacy Risks
A number of privacy risks are inherent in the Smart TV ecosystem. It is likely that many consumers are unaware of these privacy risks. Alternatively, they might be aware but consider the privacy risks acceptable. In order to explore this, we carried out an online survey with 200 participants to determine whether consumers were aware of Smart TV related privacy risks. The responses revealed a meagre level of awareness. We also explored consumers’ attitudes towards specific Smart TV related privacy risks.
We isolated a number of factors that influenced rankings and used these to develop awareness-raising messages. We tested these messages in an online survey with 155 participants. The main finding was that participants were generally unwilling to disconnect their Smart TVs from the Internet because they valued the Smart TV’s Internet functionality more than their privacy. We subsequently evaluated the awareness-raising messages in a second survey with 169 participants, framing the question differently. We asked participants to choose between five different Smart TV Internet connection options, two of which retained functionality but entailed expending time and/or effort to preserve privacy
Lattice QCD Thermodynamics on the Grid
We describe how we have used simultaneously nodes of the
EGEE Grid, accumulating ca. 300 CPU-years in 2-3 months, to determine an
important property of Quantum Chromodynamics. We explain how Grid resources
were exploited efficiently and with ease, using user-level overlay based on
Ganga and DIANE tools above standard Grid software stack. Application-specific
scheduling and resource selection based on simple but powerful heuristics
allowed to improve efficiency of the processing to obtain desired scientific
results by a specified deadline. This is also a demonstration of combined use
of supercomputers, to calculate the initial state of the QCD system, and Grids,
to perform the subsequent massively distributed simulations. The QCD simulation
was performed on a lattice. Keeping the strange quark mass at
its physical value, we reduced the masses of the up and down quarks until,
under an increase of temperature, the system underwent a second-order phase
transition to a quark-gluon plasma. Then we measured the response of this
system to an increase in the quark density. We find that the transition is
smoothened rather than sharpened. If confirmed on a finer lattice, this finding
makes it unlikely for ongoing experimental searches to find a QCD critical
point at small chemical potential
Fully compressive tides in galaxy mergers
The disruptive effect of galactic tides is a textbook example of
gravitational dynamics. However, depending on the shape of the potential, tides
can also become fully compressive. When that is the case, they might trigger or
strengthen the formation of galactic substructures (star clusters, tidal dwarf
galaxies), instead of destroying them. We perform N-body simulations of
interacting galaxies to quantify this effect. We demonstrate that tidal
compression occurs repeatedly during a galaxy merger, independently of the
specific choice of parameterization. With a model tailored to the Antennae
galaxies, we show that the distribution of compressive tides matches the
locations and timescales of observed substructures. After extending our study
to a broad range of parameters, we conclude that neither the importance of the
compressive tides (~15% of the stellar mass) nor their duration (~ 10 Myr) are
strongly affected by changes in the progenitors' configurations and orbits.
Moreover, we show that individual clumps of matter can enter compressive
regions several times in the course of a simulation. We speculate that this may
spawn multiple star formation episodes in some star clusters, through e.g.,
enhanced gas retention.Comment: 17 pages, 16 figures, accepted for publication in Ap
A Grammar Correction Algorithm – Deep Parsing and Minimal Corrections for a Grammar Checker
International audienceThis article presents the central algorithm of an open system for grammar checking, based on deep parsing. The grammatical specification is a context-free grammar with flat feature structures. After a shared-forest analysis where feature agreement constraints are relaxed, error detection globally minimizes the number of corrections and alternative correct sentences are automatically proposed in an order of plausibility reflecting the number of changes made to the original sentence
Grammaires d'erreur – correction grammaticale avec analyse profonde et proposition de corrections minimales
posterInternational audienceNous présentons un système de correction grammatical ouvert, basé sur des analyses syntaxiques profondes. La spécification grammaticale est une grammaire hors-contexte équipée de structures de traits plates. Après une analyse en forêt partagée où les contraintes d'accord de traits sont relâchées, la détection d'erreur minimise globalement les corrections à effectuer et des phrases alternatives correctes sont automatiquement proposées
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