10,537 research outputs found
Reproducibility of thoracic kyphosis measurements in patients with adolescent idiopathic scoliosis
BACKGROUND: Current surgical treatment for adolescent idiopathic scoliosis (AIS) involves correction in both the coronal and sagittal plane, and thorough assessment of these parameters is essential for evaluation of surgical results. However, various definitions of thoracic kyphosis (TK) have been proposed, and the intra- and inter-rater reproducibility of these measures has not been determined. As such, the purpose of the current study was to determine the intra- and inter-rater reproducibility of several TK measurements used in the assessment of AIS. METHODS: Twenty patients (90% females) surgically treated for AIS with alternate-level pedicle screw fixation were included in the study. Three raters independently evaluated pre- and postoperative standing lateral plain radiographs. For each radiograph, several definitions of TK were measured as well as L1âS1 and nonfixed lumbar lordosis. All variables were measured twice 14 days apart, and a mixed effects model was used to determine the repeatability coefficient (RC), which is a measure of the agreement between repeated measurements. Also, the intra- and inter-rater intra-class correlation coefficient (ICC) was determined as a measure of reliability. RESULTS: Preoperative median Cobb angle was 58° (range 41°â86°), and median surgical curve correction was 68% (range 49â87%). Overall intra-rater RC was highest for T2âT12 and nonfixed TK (11°) and lowest for T4âT12 and T5âT12 (8°). Inter-rater RC was highest for T1âT12, T1-nonfixed, and nonfixed TK (13°) and lowest for T5âT12 (9°). Agreement varied substantially between pre- and postoperative radiographs. Inter-rater ICC was highest for T4âT12 (0.92; 95% CI 0.88â0.95) and T5âT12 (0.92; 95% CI 0.88â0.95) and lowest for T1-nonfixed (0.80; 95% CI 0.72â0.88). CONCLUSIONS: Considerable variation for all TK measurements was noted. Intra- and inter-rater reproducibility was best for T4âT12 and T5âT12. Future studies should consider adopting a relevant minimum difference as a limit for true change in TK. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13013-017-0112-4) contains supplementary material, which is available to authorized users
Granular Scale Magnetic Flux Cancellations in the Photosphere
We investigate the evolution of 5 granular-scale magnetic flux cancellations
just outside the moat region of a sunspot by using accurate spectropolarimetric
measurements and G-band images with the Solar Optical Telescope aboard Hinode.
The opposite polarity magnetic elements approach a junction of the
intergranular lanes and then they collide with each other there. The
intergranular junction has strong red shifts, darker intensities than the
regular intergranular lanes, and surface converging flows. This clearly
confirms that the converging and downward convective motions are essential for
the approaching process of the opposite-polarity magnetic elements. However,
motion of the approaching magnetic elements does not always match with their
surrounding surface flow patterns in our observations. This suggests that, in
addition to the surface flows, subsurface downward convective motions and
subsurface magnetic connectivities are important for understanding the approach
and collision of the opposite polarity elements observed in the photosphere. We
find that the horizontal magnetic field appears between the canceling opposite
polarity elements in only one event. The horizontal fields are observed along
the intergranular lanes with Doppler red shifts. This cancellation is most
probably a result of the submergence (retraction) of low-lying photospheric
magnetic flux. In the other 4 events, the horizontal field is not observed
between the opposite polarity elements at any time when they approach and
cancel each other. These approaching magnetic elements are more concentrated
rather than gradually diffused, and they have nearly vertical fields even while
they are in contact each other. We thus infer that the actual flux cancellation
is highly time dependent events at scales less than a pixel of Hinode SOT
(about 200 km) near the solar surface.Comment: Accepted for publication in the Astrophysical Journa
On High-Energy Behavior of Cross Sections in Theories with Large Extra Dimensions
We discuss the high-energy behavior of cross sections in theories with large
extra dimensions and low-scale quantum gravity, addressing two particular
issues: (i) the tension of the D-branes, and (ii) bounds on the cross section
and their relation to approximations in the mode sum over Kaluza-Klein-graviton
exchanges.Comment: 6 pages, late
Superpartner spectrum of minimal gaugino-gauge mediation
We evaluate the sparticle mass spectrum in the minimal four-dimensional
construction that interpolates between gaugino and ordinary gauge mediation at
the weak scale. We find that even in the hybrid case -- when the messenger
scale is comparable to the mass of the additional gauge particles -- both the
right-handed as well as the left-handed sleptons are lighter than the bino in
the low-scale mediation regime. This implies a chain of lepton production and,
consequently, striking signatures that may be probed at the LHC already in the
near future.Comment: 8 pages, 3 figures; V2: refs and a few comments added; V3 title
change
Spt4/5 stimulates transcription elongation through the RNA polymerase clamp coiled-coil motif
Spt5 is the only known RNA polymerase-associated factor that is conserved in all three domains of life. We have solved the structure of the Methanococcus jannaschii Spt4/5 complex by X-ray crystallography, and characterized its function and interaction with the archaeal RNAP in a wholly recombinant in vitro transcription system. Archaeal Spt4 and Spt5 form a stable complex that associates with RNAP independently of the DNAâRNA scaffold of the elongation complex. The association of Spt4/5 with RNAP results in a stimulation of transcription processivity, both in the absence and the presence of the non-template strand. A domain deletion analysis reveals the molecular anatomy of Spt4/5âthe Spt5 Nus-G N-terminal (NGN) domain is the effector domain of the complex that both mediates the interaction with RNAP and is essential for its elongation activity. Using a mutagenesis approach, we have identified a hydrophobic pocket on the Spt5 NGN domain as binding site for RNAP, and reciprocally the RNAP clamp coiled-coil motif as binding site for Spt4/5
Two-loop Barr-Zee type Contributions to in the MSSM
We consider the contribution of a two-loop Barr-Zee type diagram to
in the minimal supersymmetric standard model (MSSM). At relatively
large , we show that the contribution of light third generation
scalar fermions and neutral CP-even Higgs, , can easily explain the
very recent BNL experimental data. In our analysis prefers negative
and positive . It is more sensitive to the chirality flipping
h^0(H^0)\wt{f}_R^*\wt{f}_L rather than chirality conserving couplings.Comment: 10 pages, 5 figures, references adde
(Extra)Ordinary Gauge/Anomaly Mediation
We study anomaly mediation models with gauge mediation effects from
messengers which have a general renormalizable mass matrix with a
supersymmetry-breaking spurion. Our models lead to a rich structure of
supersymmetry breaking terms in the visible sector. We derive sum rules among
the soft scalar masses for each generation. Our sum rules for the first and
second generations are the same as those in general gauge mediation, but the
sum rule for the third generation is different because of the top Yukawa
coupling. We find the parameter space where the tachyonic slepton problem is
solved. We also explore the case in which gauge mediation causes the
anomalously small gaugino masses. Since anomaly mediation effects on the
gaugino masses exist, we can obtain viable mass spectrum of the visible sector
fields.Comment: 24 pages, 10 figure
The NLO QCD Corrections to Meson Production in Decays
The decay width of to meson is evaluated at the next-to-leading
order(NLO) accuracy in strong interaction. Numerical calculation shows that the
NLO correction to this process is remarkable. The quantum
chromodynamics(QCD)renormalization scale dependence of the results is obviously
depressed, and hence the uncertainties lying in the leading order calculation
are reduced.Comment: 14 pages, 7 figures; references added; expressions and typos ammende
Tame D-tadpoles in gauge mediation
We revisit models of gauge mediated supersymmetry breaking where messenger
parity is violated. Such a symmetry is usually invoked in order to set to zero
potentially dangerous hypercharge D-term tadpoles. A milder hypothesis is that
the D-tadpole vanishes only at the first order in the gauge coupling constant.
Then the next order leads to a contribution to the sfermion masses which is of
the same magnitude as the usual radiative one. This enlarges the parameter
space of gauge mediated models. We first give a completely general
characterization of this contribution, in terms of particular three-point
functions of hidden sector current multiplet operators. We then explore the
parameter space by means of two simple weakly coupled models, where the
D-tadpole arising at two-loops has actually a mild logarithmic divergence.Comment: 13 pages + 9 pages of appendix, 1 figure; v2: some clarifying
comments added, version to appear in JHE
Z boson pair production at LHC in a stabilized Randall-Sundrum scenario
We study the Z boson pair production at LHC in the Randall-Sundrum scenario
with the Goldberger-Wise stabilization mechanism. It is shown that
comprehensive account of the Kaluza-Klein graviton and radion effects is
crucial to probe the model: The KK graviton effects enhance the cross section
of on the whole so that the resonance peak of the radion becomes
easy to detect, whereas the RS effects on the process are
rather insignificant. The and invariant-mass distributions are presented
to study the dependence of the RS model parameters. The production of
longitudinally polarized Z bosons, to which the SM contributions are
suppressed, is mainly due to KK gravitons and the radion, providing one of the
most robust methods to signal the RS effects. The sensitivity bounds
on with are also obtained such that
the effective weak scale of order 5 TeV can be experimentally
probed.Comment: 28 pages, LaTex file, 18 eps figure
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