5,964 research outputs found
Art and Praxia. Plastique and Technique in Young Children's Drawings
Children's drawings have been studied as indicating intellectual development, expressing
emotional life, revealing environmental experience, stressing problem-solving activities, but
more rarely as showing the child's artistic talents.
There are two ways of considering objets d'art: analysing and just enjoying. The present
book offers both, by showing two sets of constrained and free drawings by the same children.
The first part of the book presents a thorough experiment on the development of
constructional praxia which are compared with apraxia, i.e. acquired disability through
brain injury in adults.
The second part shows the free drawings' gallery from the same children who took part in
the first experiment.
It clearly appears that the two skills, the constructional praxic ability and the free artistic
expression, do not evolve in parallel. Very skilled children often are poor artists and the
observer can find aesthetic drawings in young and praxically unskilled children. In other
words, already in the 4 to 7 age bracket, the artisan does not make the artist.
However, the authors avoid any classification in art
Longitudinal Spin Asymmetry and Cross Section of Inclusive pi0 Production in Polarized p+p Collisions at RHIC
We present the first measurement of the cross section and the double
longitudinal spin asymmetry of inclusive pi0 production in polarized p+p
collisions at Sqrt(s) = 200 GeV at mid-rapidity with the STAR detector, using
the barrel electromagnetic calorimeter. The measured cross section is compared
to NLO pQCD calculations and can provide constraints on the pion fragmentation
functions. Fragmentation is studied directly by measuring the momentum fraction
of pi0 in jets, a quantity that is affected by the fragmentation process and
jet reconstruction effects. The double longitudinal spin asymmetry is compared
to NLO pQCD calculations based on different assumptions for the gluon
polarization in the nucleon to provide constraints on delta g/g. At the present
level of statistics the measured asymmetry disfavors a large positive gluon
polarization, but can not yet distinguish between other scenarios.Comment: 4 pages, 2 figures, submitted to the proceedings of the 17th
International Spin Physics Symposium (SPIN2006), Kyoto, Japan, October 2 to
7, 200
Gravity duals of 2d supersymmetric gauge theories
We find new supergravity solutions generated by D5-branes wrapping a
four-cycle and preserving four and two supersymmetries. We first consider the
configuration in which the fivebranes wrap a four-cycle in a Calabi-Yau
threefold, which preserves four supersymmetries and is a gravity dual to the
Coulomb branch of two-dimensional gauge theories with N=(2,2) supersymmetry. We
also study the case of fivebranes wrapping a co-associative four-cycle in a
manifold of G_2-holonomy, which provides a gravity dual of N=(1,1)
supersymmetric Yang-Mills theory in two dimensions. We also discuss the
addition of unquenched fundamental matter fields to these backgrounds and find
the corresponding gravity solutions with flavor brane sources.Comment: 34 pages + appendices; v2: minor improvement
An Integrated Tracker for STAR
The STAR experiment at the Relativistic Heavy Ion Collider RHIC studies the
new state of matter produced in relativistic heavy ion collisions and the spin
structure of the nucleon in collisions of polarized protons. In order to
improve the capabilities for heavy flavor measurements and the reconstruction
of charged vector bosons an upgrade of the tracking system both in the central
and the forward region is pursued. The integrated system providing high
resolution tracking and secondary vertex reconstruction capabilities will use
silicon pixel, strip and GEM technology.Comment: 4 pages, 2 figures, to be published in the Proceedings of the 9th
Conference on the Intersections of Particle and Nuclear Physics (CIPANP
2006), Rio Grande, Puerto Rico, May 30 - June 3, 200
Developmental Risk: Evidence from Large Nonrighthanded Samples
The aim of the present study is twofold. First, we tested the view that individuals who do not develop a typically strong behavioral
laterality are distributed differentially among the two genders across age. Second, we examined whether left handedness and mixed
handedness are associated with an elevated risk of some developmental or cognitive deficits. A special recruitment procedure
provided norms of the Rey-Osterrieth Complex Figure (ROCF) copy from large samples of left-handed ( = 420) and mixedhanded
( = 72) compared to right-handed ( = 420) schoolchildren and adults ( = 545). This graphic task was considered as
reflective of the growth of visual-spatial skills and impairment at copying as a developmental risk. Subjects' hand preference was
assessed by the Edinburgh Handedness Inventory. Data analysis indicated that (1) the trend towards consistent right handedness
is sex related. Girls are clearly ahead of boys in this lateralization process, and boys are overrepresented in mixed-handed subjects.
The greater prevalence of mixed-handed boys compared to girls decreases with age. (2) Performance on drawing the ROCF varies
according to age and handedness groups.Mixed-handed subjects scoredworse in all age groups.The results are discussed in relation
to the hormonal-developmental, neuropathological, and learning theories of lateralization
Inclusive Hadron Production in p+p Collisions at STAR
The STAR experiment at RHIC has measured a variety of inclusive hadron cross
sections in collisions at Sqrt(s) = 200 GeV. Measurements of the
differential cross section for inclusive charged pion production at mid
rapidity and for inclusive neutral pion production at forward rapidity (3.0 <
eta < 4.2) as well as the first preliminary result from STAR for the
differential cross section for inclusive neutral pion production near mid
rapidity are presented. These cross sections are compared to next-to-leading
order perturbative QCD calculations and can provide constraints on the pion
fragmentation functions. Good agreement between data and pQCD has been found
for all three cross sections.Comment: 4 pages, 1 figure, to be published in the Proceedings of the 9th
Conference on the Intersections of Particle and Nuclear Physics (CIPANP
2006), Rio Grande, Puerto Rico, May 30 - June 3, 2006, v2 with updated
reference
Lepton-Flavour Violation in Ordinary and Supersymmetric Grand Unified Theories
By an explicit calculation we show that in ordinary SU(5) logarithmic
divergence in the amplitude of cancels among diagrams and
remaining finite part is suppressed by at least . In SUSY SU(5),
when the effect of flavour changing wave function renormalization is taken into
account such logarithmic correction disappears, provided a condition is met
among SUSY breaking masses. In SUGRA-inspired SUSY GUT the remaining
logarithmic effect is argued not to be taken as a prediction of the theory.Comment: 8 pages, LaTeX209 file, using axodraw.st
One-loop Regularization of Supergravity II: The Dilaton and the Superfield Formulation
The on-shell regularization of the one-loop divergences of supergravity
theories is generalized to include a dilaton of the type occurring in effective
field theories derived from superstring theory, and the superfield structure of
the one-loop corrections is given. Field theory anomalies and quantum
contributions to soft supersymmetry breaking are discussed. The latter are
sensitive to the precise choice of couplings that generate Pauli-Villars
masses, which in turn reflect the details of the underlying theory above the
scale of the effective cut-off. With a view to the implementation the
Green-Schwarz and other mechanisms for canceling field theory anomalies under a
U(1) gauge transformation and under the T-duality group of modular
transformations, we show that the K\"ahler potential renormalization for the
untwisted sector of orbifold compactification can be made invariant under these
groups.Comment: 46 pages, full postscript also available from
http://phyweb.lbl.gov/theorygroup/papers/43259.p
The Holographic Dual of 2+1 Dimensional QFTs with N=1 SUSY and Massive Fundamental Flavours
The Maldacena Nastase solution is generalised to include massive fundamental
matter through the addition of a flavour profile. This gives a holographic dual
to N=1 SYM-CS with massive fundamental matter with a singularity free IR. We
study this solution in some detail confirming confinement and asymptotic
freedom. A recently proposed solution generating technique is then applied
which results in a new type-IIA supergravity solution. In a certain limit the
geometry of this solution is asymptotically AdS_4X Y, where Y is the metric at
the base of the Bryant-Salamon G_2 cone, which has topology S^3XS^3.Comment: 31 pages plus appendices, 6 figures. v3: Typos corrected, version to
appear in JHE
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