1,917 research outputs found
Effects of Juvenile Idiopathic Arthritis on Kinematics and Kinetics of the Lower Extremities Call for Consequences in Physical Activities Recommendations
Juvenile idiopathic arthritis (JIA) patients (n = 36) with symmetrical polyarticular joint involvement of the lower extremities and healthy controls (n = 20) were compared concerning differences in kinematic, kinetic, and spatio-temporal parameters with 3D gait analysis. The aims of this study were to quantify the differences in gait between JIA patients and healthy controls and to provide data for more detailed sport activities recommendations. JIA-patients showed reduced walking speed and step length, strongly anterior tilted pelvis, reduced maximum hip extension, reduced knee extension during single support phase and reduced plantar flexion in push off. Additionally the roll-off procedure of the foot was slightly decelerated. The reduced push off motion in the ankle was confirmed by lower peaks in ankle moment and power. The gait of JIA-patients can be explained as a crouch-like gait with hyperflexion in hip and knee joints and less plantar flexion in the ankle. A preventive mobility workout would be recommendable to reduce these restrictions in the future. Advisable are sports with emphasis on extension in hip, knee, and ankle plantar flexion
Low-lying GT(+) strength in Co-64 studied via the Ni-64(d,He-2)Co-64 reaction
The Ni-64(d,He-2)Co-64 reaction was studied at the AGOR cyclotron of KVI, Groningen, with the Big-Bite Spectrometer and the EuroSuperNova detector using a 171-MeV deuteron beam. An energy resolution of about 110 keV was achieved. In addition to the J(pi) = 1(+) ground state, several other 1(+) states could be identified in Co-64 and the strengths of the corresponding Gamow-Teller transitions were determined. The obtained strength distribution was compared with theoretical predictions and former (n,p) experimental results and displayed a good agreement. Due to the good energy resolution, detailed spectroscopic information was obtained, which supplements the data base needed for network calculations for supernova scenarios
A tomographic study of the classical nova RR Pic
We present the results of spectrophotometric observations of the old nova RR
Pic performed in two spectral ranges, one centered in the Ha line and other
covering Hb and Hg spectral lines. From the Hb radial velocity study we found a
primary radial semi-amplitude of K1 = 37(1) km/s and a systemic velocity of g =
1.8(2) km/s. With this new values a mass diagram is constructed, constraining
the possible mass intervals for the system. The possible orbital inclination
range was restricted using the fact that RR Pic presents shallow eclipses. A
secondary mass range below the limit of a main sequence star filling its Roche
lobe indicate an evolved companion. We also calculated the Ha, Hb, Hg, HeI 6678
and HeII 4686 Doppler tomograms. The most conspicuous differences are found
between the HeI and HeII tomograms, the former has a ring shape, while the
second is filled at low velocities, suggesting that the low velocity emission
is not coming from the accretion disk. Radial emissivity profiles for these
lines were also derived.Comment: 8 pages, 8 figures, accepted to appear in PAS
Effects of threatening communications and mothers' health beliefs on weight change in obese children
A field experiment was designed to test the effects on weight change in obese children of (1) communications varying in threat and (2) health beliefs of the child's mother, in terms of perceived vulnerability to health threats, the efficacy of taking actions, and barriers to acting. Treatments involved messages containing more or less threatening material regarding obesity, plus a control (no communication) condition. Beliefs were assessed by means of personal interviews. All mothers and children received dietary counseling and were scheduled for four follow-up visits, which included weighing. The 182 participants were from low-income areas served by a large hospital pediatric clinic. High-threat messages yielded the most consistent weight loss, followed by low threat and control. In addition, both general beliefs concerning health and specific beliefs about obesity and dieting predicted weight loss. Both messages and mothers' beliefs acted together on keeping appointments and making efforts to comply. Results are discussed in terms of the effects of threats and health belief-behavior linkages.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44808/1/10865_2004_Article_BF00846636.pd
Swift J1753.5-0127: The Black Hole Candidate with the shortest orbital period
We present time-resolved photometry of the optical counterpart to the black
hole candidate Swift J1753.5-0127, which has remained in the low/hard X-ray
state and bright at optical/IR wavelengths since its discovery in 2005. At the
time of our observations Swift J1753.5-0127 does not show a decay trend but
remains stable at R=16.45 with a night to night variability of ~0.05 mag. The
R-band light curves, taken from 2007 June 3 to August 31, are not sinusoidal,
but exhibit a complex morphology with remarkable changes in shape and
amplitude. The best period determination is 3.2443+-0.0010 hours. This
photometric period is likely a superhump period, slightly larger than the
orbital period. Therefore, Swift J1753.5-0127 is the black hole candidate with
the shortest orbital period observed to date. Our estimation of the distance is
comparable to values previously published and likely places Swift J1753.5-0127
in the Galactic halo.Comment: Accepted for publication in Ap
Results from the Commissioning of the n-TOF Spallation Neutron Source at CERN
The new neutron time-of-flight facility (n_TOF) has been built at CERN and is now operational. The facility is intended for the measurement of neutron induced cross sections of relevance to Accelerator Driven Systems (ADS) and to fundamental physics. Neutrons are produced by spallation of the 20 GeV/c proton beam, delivered by the Proton Synchrotron (PS), on a massive target of pure lead. A measuring station is placed at about 185 m from the neutron producing target, allowing high-resolution measurements. The facility was successfully commissioned with two campaigns of measurements, in Nov. 2000 and Apr. 2001. The main interest was concentrated in the physical parameters of the installation (neutron flux and resolution function), along with the target behavior and various safety-related aspects. These measurements confirmed the expectations from Monte Carlo simulations of the facility, thus allowing to initiate the foreseen physics program
Dwarf Nova Oscillations and Quasi-Periodic Oscillations in Cataclysmic Variables: III. A New Kind of Dwarf Nova Oscillation, and Further Examples of the Similarities to X-Ray Binaries
We present measurements of the periods of Dwarf Nova Oscillations (DNOs) and
Quasi-Periodic Oscillations (QPOs) in Cataclysmic Variable stars (CVs), many
culled from published literature, but also others newly observed (in VZ Pyx, CR
Boo, OY Car, Z Cha, AQ Eri, TU Men, HX Peg, CN Ori, V893 Sco, WX Hyi and
EC2117-54). These provide data for 26 systems. We show that in general P_QPO ~
15 P_DNO and that the correlation for CVs extends by three orders of magnitude
lower in frequency the similar relationship found for X-Ray binaries. In
addition, we have found that there is a second type of DNO, previously
overlooked, which have periods ~ 4 times those of the regular DNOs (As well as
those mined from publications, we have observed them in VW Hyi, OY Car, AQ Eri,
V803 Cen, CR Boo, VZ Pyx, HX Peg and EC2117-54). Often both types of DNO
coexist. Unlike the standard DNOs, the periods of the new type, which we refer
to as longer period DNOs (lpDNOs), are relatively insensitive to accretion
luminosity and can even appear in quiescence of dwarf novae. We interpret them
as magnetically channelled accretion onto the differentially rotating main body
of the white dwarf primary, rather than onto a rapidly slipping equatorial belt
as in the case of the standard DNOs. This is supported by published
measurements of v sin(i) for some of the primaries. Some similarities of the
DNOs, lpDNOs and QPOs in CVs to the three types of QPO in X-Ray binaries (burst
pulsation, high and low frequency QPOs) are noted.Comment: 19 pages, 30 figures. To appear in MNRA
Interparticle interactions:Energy potentials, energy transfer, and nanoscale mechanical motion in response to optical radiation
In the interactions between particles of material with slightly different electronic levels, unusually large shifts in the pair potential can result from photoexcitation, and on subsequent electronic excitation transfer. To elicit these phenomena, it is necessary to understand the fundamental differences between a variety of optical properties deriving from dispersion interactions, and processes such as resonance energy transfer that occur under laser irradiance. This helps dispel some confusion in the recent literature. By developing and interpreting the theory at a deeper level, one can anticipate that in suitable systems, light absorption and energy transfer will be accompanied by significant displacements in interparticle separation, leading to nanoscale mechanical motion
Catalog of Galactic Beta Cephei Stars
We present an extensive and up-to-date catalog of Galactic Beta Cephei stars.
This catalog is intended to give a comprehensive overview of observational
characteristics of all known Beta Cephei stars. 93 stars could be confirmed to
be Beta Cephei stars. For some stars we re-analyzed published data or conducted
our own analyses. 61 stars were rejected from the final Beta Cephei list, and
77 stars are suspected to be Beta Cephei stars. A list of critically selected
pulsation frequencies for confirmed Beta Cephei stars is also presented. We
analyze the Beta Cephei stars as a group, such as the distributions of their
spectral types, projected rotational velocities, radial velocities, pulsation
periods, and Galactic coordinates. We confirm that the majority of these stars
are multiperiodic pulsators. We show that, besides two exceptions, the Beta
Cephei stars with high pulsation amplitudes are slow rotators. We construct a
theoretical HR diagram that suggests that almost all 93 Beta Cephei stars are
MS objects. We discuss the observational boundaries of Beta Cephei pulsation
and their physical parameters. We corroborate that the excited pulsation modes
are near to the radial fundamental mode in frequency and we show that the mass
distribution of the stars peaks at 12 solar masses. We point out that the
theoretical instability strip of the Beta Cephei stars is filled neither at the
cool nor at the hot end and attempt to explain this observation
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