406 research outputs found
Relations between cognition and motricity in children with neonatal arterial ischemic stroke
Introduction and goalPerinatal arterial ischemic stroke (PAIS) affects one child for 4000 births. The few studies about cognitive development specific to PAIS showed that cognitive performances in this population do not follow up a normal development (Westmacott et al., 2010; Ricci et al., 2008). Based on new data about relation between motricity and cognition (Smits-Engelsman et Hill, 2012), and on the theory of the embodied cognition, led us to hypothesize that cognitive performances would be correlated to the motor performances in children with PAIS.Patients and methodologyWe tested 77 7 years old children meeting the criteria of neonatal AIS, with a diagnosis before the 28th day of life relying on cerebral imagery. After excluding children with seizure and bi-hemispheric lesion, 56 children participated to our study. The cognitive evaluation was performed with the Wechsler Intelligence Scale for Children (WISC-4), the motor evaluation relied on testing of gross motor of the upper arm (Box and Block Test) and fine prehension test (âNine Hole Peg Testâ). The localisation of the lesion, the economic level of parents, the gender, sensory impairments and the presence of hemiplegia were collected. We analyzed these results with simple linear regression.ResultsThe main result of our study is the significative correlation (P<0.03) between scores of the WISC4 (except for working memory index) and motor results. In contrast we did not find any correlation between the scores of the WISC4 and the presence of hemiplegia or with lesion localization.DiscussionMany brain networks develop during the first year through sensorimotor experiences, which contribute to the emergence of knowledge. This concept of development, supported by the approach embodied cognition, can explain the correlations between cognition and motor found in our work and in several studies with children with other early neurological damage
Nambu-Poisson manifolds and associated n-ary Lie algebroids
We introduce an n-ary Lie algebroid canonically associated with a
Nambu-Poisson manifold. We also prove that every Nambu-Poisson bracket defined
on functions is induced by some differential operator on the exterior algebra,
and characterize such operators. Some physical examples are presented
Polarised target for Drell-Yan experiment in COMPASS at CERN, part I
In the polarised Drell-Yan experiment at the COMPASS facility in CERN pion
beam with momentum of 190 GeV/c and intensity about pions/s interacted
with transversely polarised NH target. Muon pairs produced in Drel-Yan
process were detected. The measurement was done in 2015 as the 1st ever
polarised Drell-Yan fixed target experiment. The hydrogen nuclei in the
solid-state NH were polarised by dynamic nuclear polarisation in 2.5 T
field of large-acceptance superconducting magnet. Large helium dilution
cryostat was used to cool the target down below 100 mK. Polarisation of
hydrogen nuclei reached during the data taking was about 80 %. Two oppositely
polarised target cells, each 55 cm long and 4 cm in diameter were used.
Overview of COMPASS facility and the polarised target with emphasis on the
dilution cryostat and magnet is given. Results of the polarisation measurement
in the Drell-Yan run and overviews of the target material, cell and dynamic
nuclear polarisation system are given in the part II.Comment: 4 pages, 2 figures, Proceedings of the 22nd International Spin
Symposium, Urbana-Champaign, Illinois, USA, 25-30 September 201
Polarization build up in COMPASS 6LiD target
The CERN COMPASS experiment uses a large double 424 cm3 cell polarized 6LiD target for the muon program. High nuclear spin polarization |P| > 50 % is obtained, typically in five days. The high cooling power of the COMPASS dilution refrigerator helps to build up the polarization fast at temperatures around 300 mK. At lower microwave power with lower spin and lattice temperatures, the polarization build up is slower. We discuss these features of the dynamic nuclear polarization of our 6LiD target
The Schouten-Nijenhuis bracket, cohomology and generalized Poisson structures
Newly introduced generalized Poisson structures based on suitable
skew-symmetric contravariant tensors of even order are discussed in terms of
the Schouten-Nijenhuis bracket. The associated `Jacobi identities' are
expressed as conditions on these tensors, the cohomological contents of which
is given. In particular, we determine the linear generalized Poisson structures
which can be constructed on the dual spaces of simple Lie algebras.Comment: 29 pages. Plain TeX. Phyzzx needed. An example and some references
added. To appear in J. Phys.
Detrital zircon and apatite (UâTh)/He geochronology of intercalated baked sediments: a new approach to dating young basalt flows
The historical fertility transition at the micro level: Southern Sweden 1815-1939
<b>Background</b>: We know a great deal about the historical fertility transition at the macro level. The dominating focus on the macro level in previous research on the fertility transition means, however, that to a large extent we lack knowledge about details of the decline and empirical tests of the leading explanatory frameworks. <b>Objective</b>: Our aim is to explore socioeconomic fertility differentials in an industrializing community, to gain insight about the details and discuss possible mechanisms. The study starts well before industrialization and finishes at the end of the transition. <b>Methods</b>: We use longitudinal individual-level data from the Scanian Economic-Demographic Database, which contains demographic as well as socioeconomic information, including occupation, landholding, and income. In the analysis we use hazard regressions with shared frailty at the family level. <b>Results</b>: The transition involved not only parity-specific stopping but also spacing. While the upper social strata had higher fertility prior to the transition, they started to control their fertility earlier, by the 1880s, and also more consistently. Farmers, the middle class, and skilled workers followed in the decades after, and unskilled workers with some additional delay. <b>Conclusions</b>: These findings are partly inconsistent with several of the major explanations in the literature, such as mortality decline, increased female labor force participation, and a quantity-quality trade-off, but consistent with an innovation process where new ideas and attitudes about family limitation spread from the elite to other social groups. <b>Comments</b>: Further studies are required to empirically test the innovation-diffusion theory
On Deformations of n-Lie algebras
The aim of this paper is to review the deformation theory of -Lie
algebras. We summarize the 1-parameter formal deformation theory and provide a
generalized approach using any unital commutative associative algebra as a
deformation base. Moreover, we discuss degenerations and quantization of
-Lie algebras.Comment: Proceeding of the conference Dakar's Workshop in honor of Pr Amin
Kaidi. arXiv admin note: text overlap with arXiv:hep-th/9602016 by other
author
Classical and Quantum Nambu Mechanics
The classical and quantum features of Nambu mechanics are analyzed and
fundamental issues are resolved. The classical theory is reviewed and developed
utilizing varied examples. The quantum theory is discussed in a parallel
presentation, and illustrated with detailed specific cases. Quantization is
carried out with standard Hilbert space methods. With the proper physical
interpretation, obtained by allowing for different time scales on different
invariant sectors of a theory, the resulting non-Abelian approach to quantum
Nambu mechanics is shown to be fully consistent.Comment: 44 pages, 1 figure, 1 table Minor changes to conform to journal
versio
On the generalizations of Poisson structures
The characterization of the Nambu-Poisson n-tensors as a subfamily of the
Generalized-Poisson ones recently introduced (and here extended to the odd
order case) is discussed. The homology and cohomology complexes of both
structures are compared, and some physical considerations are made.Comment: Latex file. 12 pages. Trivial changes, a misprint (subindices)
corrected. To appear in J. Phys. A (letters
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