376 research outputs found
The effect of level of knowledge accuracy of results on learning of motor skills in children and adults
The level of knowledge accuracy of results (KR) is a variable that interferes with the learning of motor skills, however such interference does not work the same way in adults and children. This study examined the effects of KR in children and adults during learning of a manipulative task with target accuracy. Forty adults (female = 21.13 ± 2.26 years; male = 20.97 ± 2.17 years) and forty children (female = 9.10 ± .83 years; male = 9.70 ± .48 years) practiced a task of hitting a target placed on a table by the thrown of metal discs. There were six experimental groups and two control groups (without KR) containing 10 subjects each. Experimental groups differed according to the individual's KR (less precise KR, precise KR and very precise KR) and development level (children and adult). Performance measure was the absolute error (AE). A three-way (age × groups × blocks) and two-way (groups × blocks) analysis of variance for the stabilization and adaptation phases were used. Results showed that adults perform better than children in low and intermediate KR and in high KR adults and children showed similar performance
Gender and age differences in polysomnography findings and sleep complaints of patients referred to a sleep laboratory
Our objective was to examine the effet of gender on the sleep pattern of patients referred to a sleep laboratory. The data (questionnaires and polysomnographic recordings) were collected from a total of 2365 patients (1550 men and 815 women). The polysomnography permits an objective assessment of the sleep pattern. We included only polysomnography exams obtained with no more than one recording system in order to permit normalization of the data. Men had a significantly higher body mass index than women (28.5 ± 4.8 vs 27.7 ± 6.35 kg/m²) and had a significantly higher score on the Epworth Sleepiness Scale (10.8 ± 5.3 vs 9.5 ± 6.0), suggesting daytime sleepiness. Women had a significantly higher sleep latency than men, as well as a higher rapid eye movement (REM) latency. Men spent more time in stages 1 (4.6 ± 4.1 vs 3.9 ± 3.8) and 2 (57.0 ± 10.5 vs 55.2 ± 10.1) of non-REM sleep than women, whereas women spent significantly more time in deep sleep stages (3 and 4) than men (22.6 ± 9.0 vs 19.9 ± 9.0). The apnea/hypopnea and arousal indexes were significantly higher and more frequent in men than in women (31.0 ± 31.5 vs 17.3 ± 19.7). Also, periodic leg movement index did not differ significantly between genders, but rather differed among age groups. We did not find significant differences between genders in the percentage of REM sleep and sleep efficiency. The results of the current study suggest that there are specific gender differences in sleep pattern.1067107
Giant Gravitons - with Strings Attached (III)
We develop techniques to compute the one-loop anomalous dimensions of
operators in the super Yang-Mills theory that are dual to open
strings ending on boundstates of sphere giant gravitons. Our results, which are
applicable to excitations involving an arbitrary number of open strings,
generalize the single string results of hep-th/0701067. The open strings we
consider carry angular momentum on an S embedded in the S of the
AdSS background. The problem of computing the one loop anomalous
dimensions is replaced with the problem of diagonalizing an interacting Cuntz
oscillator Hamiltonian. Our Cuntz oscillator dynamics illustrates how the
Chan-Paton factors for open strings propagating on multiple branes can arise
dynamically.Comment: 66 pages; v2: improved presentatio
Relationship between work rate and oxygen uptake in mitochondrial myopathy during ramp-incremental exercise
We determined the response characteristics and functional correlates of the dynamic relationship between the rate (Δ) of oxygen consumption ( O2) and the applied power output (work rate = WR) during ramp-incremental exercise in patients with mitochondrial myopathy (MM). Fourteen patients (7 males, age 35.4 ± 10.8 years) with biopsy-proven MM and 10 sedentary controls (6 males, age 29.0 ± 7.8 years) took a ramp-incremental cycle ergometer test for the determination of the O2 on-exercise mean response time (MRT) and the gas exchange threshold (GET). The ΔO2/ΔWR slope was calculated up to GET (S1), above GET (S2) and over the entire linear portion of the response (S T). Knee muscle endurance was measured by isokinetic dynamometry. As expected, peak O2 and muscle performance were lower in patients than controls (P O2/ΔWR than controls, especially the S2 component (6.8 ± 1.5 vs 10.3 ± 0.6 mL·min-1·W-1, respectively; P O2/ΔWR (S T) and muscle endurance, MRT-O2, GET and peak O2 in MM patients (P O2/ΔWR below 8 mL·min-1·W-1 had severely reduced peak O2 values (O2) had lower ΔO2/ΔWR (P O2/ΔWR) is typically reduced in patients with MM, being related to increased functional impairment and higher cardiopulmonary stress
Non-holomorphic multi-matrix gauge invariant operators based on Brauer algebra
We present an orthogonal basis of gauge invariant operators constructed from
some complex matrices for the free matrix field, where operators are expressed
with the help of Brauer algebra. This is a generalisation of our previous work
for a signle complex matrix. We also discuss the matrix quantum mechanics
relevant to N=4 SYM on S^{3} times R. A commuting set of conserved operators
whose eigenstates are given by the orthogonal basis is shown by using enhanced
symmetries at zero coupling.Comment: 29 pages, typos corrected, references adde
Electrified BPS Giants: BPS configurations on Giant Gravitons with Static Electric Field
We consider D3-brane action in the maximally supersymmetric type IIB
plane-wave background. Upon fixing the light-cone gauge, we obtain the
light-cone Hamiltonian which is manifestly supersymmetric. The 1/2 BPS
solutions of this theory (solutions which preserve 16 supercharges) are either
of the form of spherical three branes, the giant gravitons, or zero size point
like branes. We then construct specific classes of 1/4 BPS solutions of this
theory in which static electric field on the brane is turned on. These
solutions are deformations about either of the two 1/2 BPS solutions. In
particular, we study in some detail 1/4 BPS configurations with electric dipole
on the three sphere giant, i.e. BIons on the giant gravitons, which we hence
call BIGGons. We also study BPS configurations corresponding to turning on a
background uniform constant electric field. As a result of this background
electric field the three sphere giant is deformed to squashed sphere, while the
zero size point like branes turn into circular or straight fundamental strings
in the plane-wave background, with their tension equal to the background
electric field.Comment: 32 pages, 1 eps figure; v2: Presentation of derivation of light-cone
Hamiltonian improved, Refs adde
Half-BPS Giants, Free Fermions and Microstates of Superstars
We consider 1/2-BPS states in AdS/CFT. Using the matrix model description of
chiral primaries explicit mappings among configurations of fermions, giant
gravitons and the dual-giant gravitons are obtained. These maps lead to a
`duality' between the giant and the dual-giant configurations which is the
reflection of particle-hole duality of the fermion picture. These dualities
give rise to some interesting consequences which we study. We then calculate
the degeneracy of 1/2-BPS states both from the CFT and string theory and show
that they match. The asymptotic degeneracy grows exponentially with the
comformal dimension. We propose that the five-dimensional single charge
`superstar' geometry should carry this density of states. An appropriate
stretched horizon can be placed in this geometry and the entropy predicted by
the CFT and the string theory microstate counting can be reproduced by the
Bekenstein-Hawking formula up to a numerical coefficient. Similar M-theory
examples are also considered.Comment: 21 pages, v2:typos corrected and references adde
Branes, Anti-Branes and Brauer Algebras in Gauge-Gravity duality
We propose gauge theory operators built using a complex Matrix scalar which
are dual to brane-anti-brane systems in , in the zero
coupling limit of the dual Yang-Mills. The branes involved are half-BPS giant
gravitons. The proposed operators dual to giant-anti-giant configurations
satisfy the appropriate orthogonality properties. Projection operators in
Brauer algebras are used to construct the relevant multi-trace Matrix
operators. These are related to the ``coupled representations'' which appear in
2D Yang-Mills theory. We discuss the implications of these results for the
quantum mechanics of a complex matrix model, the counting of non-supersymmetric
operators and the physics of brane-anti-brane systems. The stringy exclusion
principle known from the properties of half-BPS giant gravitons, has a new
incarnation in this context. It involves a qualitative change in the map
between brane-anti-brane states to gauge theory operators. In the case of a
pair of sphere giant and anti-giant this change occurs when the sum of the
magnitudes of their angular momenta reaches .Comment: 52 pages, 10 figure
Thermal Giant Graviton with Non-commutative Dipole Field
Using the type II near-extremal 3D-branes solution we apply the T-duality and
smeared twist to construct the supergravity backgrounds which dual to the 4D
finite temperature non-commutative dipole field theories. We first consider the
zero-temperature system in which, depending on the property of dipole vectors
it may be N=2, N=1 or N=0 theory. We investigate the rotating D3-brane
configurations moving on the spactimes and show that, for the cases of N=2 and
N =1 the rotating D3-brane could be blowed up to the stable spherical
configuration which is called as giant graviton and has a less energy than the
point-like graviton. The giant graviton configuration is stable only if its
angular momentum was less than a critical value of which is an increasing
function of the dipole strength. For the case of non-supersymmetric theory,
however, the spherical configuration has a larger energy than the point-like
graviton. We also find that the dipole field always render the dual giant
graviton to be more stable than the point-like graviton. The relation of dual
giant graviton energy with its angular momentum, which in the AdS/CFT
correspondence being the operator anomalous dimension is obtained. We
furthermore show that the temperature does not change the property of the giant
graviton, while it will render the dual giant graviton to be unstable.Comment: Latex 20 pages, add comments about BPS bound below (3.8
Changes In Motor Behavior During Pregnancy In Rats: The Basis For A Possible Animal Model Of Restless Legs Syndrome [alterações No Comportamento Motor De Ratas Prenhes: Bases Para Um Possível Modelo Animal Da Síndrome Das Pernas Inquietas]
PURPOSE: Pregnant women have a 2-3 fold higher probability of developing restless legs syndrome (RLS – sleep-related movement disorders) than general population. This study aims to evaluate the behavior and locomotion of rats during pregnancy in order to verify if part of these animals exhibit some RLS-like features. METHODS: We used 14 female 80-day-old Wistar rats that weighed between 200 and 250 g. The rats were distributed into control (CTRL) and pregnant (PN) groups. After a baseline evaluation of their behavior and locomotor activity in an open-field environment, the PN group was inducted into pregnancy, and their behavior and locomotor activity were evaluated on days 3, 10 and 19 of pregnancy and in the post-lactation period in parallel with the CTRL group. The serum iron and transferrin levels in the CTRL and PN groups were analyzed in blood collected after euthanasia by decapitation. RESULTS: There were no significant differences in the total ambulation, grooming events, fecal boli or urine pools between the CTRL and PN groups. However, the PN group exhibited fewer rearing events, increased grooming time and reduced immobilization time than the CTRL group (ANOVA, p<0.05). 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