607 research outputs found
Combined rotation scarf and Akin osteotomies for hallux valgus: a patient focussed 9 year follow up of 50 patients
<p>Abstract</p> <p>Background</p> <p>The Cochrane review of hallux valgus surgery has disputed the scientific validity of hallux valgus research. Scoring systems and surrogate measures such as x-ray angles are commonly reported at just one year post operatively but these are of dubious relevance to the patient. In this study we extended the follow up to a minimum of 8 years and sought to address patient specific concerns with hallux valgus surgery. The long term follow up also allowed a comprehensive review of the complications associated with the combined rotation scarf and Akin osteotomies.</p> <p>Methods</p> <p>Between 1996 and 1999, 101 patients underwent rotation scarf and Akin osteotomies for the treatment of hallux valgus. All patients were contacted and asked to participate in this study. 50 female participants were available allowing review of 73 procedures. The average follow up was over 9 years and the average age at the time of surgery was 57. The participants were physically examined and interviewed.</p> <p>Results</p> <p>Post-operatively, in 86% of the participants there were no footwear restrictions. Stiffness of the first metatarsophalangeal joint was reported in 8% (6 feet); 10% were unhappy with the cosmetic appearance of their feet, 3 feet had hallux varus, and 2 feet had recurrent hallux valgus. There were no foot-related activity restrictions in 92% of the group. Metatarsalgia occurred in 4% (3 feet). 96% were better than before surgery and 88% were completely satisfied with their post-operative result. Hallux varus was the greatest single cause of dissatisfaction. The most common adverse event in the study was internal fixation irritation. Hallux valgus surgery is not without risk and these findings could be useful in the informed consent process.</p> <p>Conclusions</p> <p>When combined the rotation scarf and Akin osteotomies are an effective treatment for hallux valgus that achieves good long-term correction with a low incidence of recurrence, footwear restriction or metatarsalgia. The nature of the osteotomies allows early return to normal shoes and activity without the need for postoperative immobilisation in a plaster cast.</p
The Mt John University Observatory Search For Earth-mass Planets In The Habitable Zone Of Alpha Centauri
The "holy grail" in planet hunting is the detection of an Earth-analog: a
planet with similar mass as the Earth and an orbit inside the habitable zone.
If we can find such an Earth-analog around one of the stars in the immediate
solar neighborhood, we could potentially even study it in such great detail to
address the question of its potential habitability. Several groups have focused
their planet detection efforts on the nearest stars. Our team is currently
performing an intensive observing campaign on the alpha Centauri system using
the Hercules spectrograph at the 1-m McLellan telescope at Mt John University
Observatory (MJUO) in New Zealand. The goal of our project is to obtain such a
large number of radial velocity measurements with sufficiently high temporal
sampling to become sensitive to signals of Earth-mass planets in the habitable
zones of the two stars in this binary system. Over the past years, we have
collected more than 45,000 spectra for both stars combined. These data are
currently processed by an advanced version of our radial velocity reduction
pipeline, which eliminates the effect of spectral cross-contamination. Here we
present simulations of the expected detection sensitivity to low-mass planets
in the habitable zone by the Hercules program for various noise levels. We also
discuss our expected sensitivity to the purported Earth-mass planet in an
3.24-d orbit announced by Dumusque et al.~(2012).Comment: 16 pages, 7 figures, accepted for publication in the International
Journal of Astrobiolog
Spectroscopic Pulsational Frequency Identification and Mode Determination of Gamma Doradus Star HD135825
We present the mode identification of frequencies found in spectroscopic
observations of the Gamma Doradus star HD135825. Four frequencies were
successfully identified: 1.3150 +/- 0.0003 1/d; 0.2902 +/- 0.0004 1/d; 1.4045
+/- 0.0005 1/d; and 1.8829 +/- 0.0005 1/d. These correspond to (l, m) modes of
(1,1), (2,-2), (4,0) and (1,1) respectively. Additional frequencies were found
but they were below the signal-to-noise limit of the Fourier spectrum and not
suitable for mode identification. The rotational axis inclination and vsini of
the star were determined to be 87 degrees (nearly edge-on) and 39.7 km/s
(moderate for Gamma Doradus stars) respectively. A simultaneous fit of these
four modes to the line profile variations in the data gives a reduced chi
square of 12.7. We confirm, based on the frequencies found, that HD135825 is a
bona fide Gamma Doradus star.Comment: Accepted to MNRAS 2012 March
MOA 2003-BLG-37: A Bulge Jerk-Parallax Microlens Degeneracy
We analyze the Galactic bulge microlensing event MOA-2003-BLG-37. Although
the Einstein timescale is relatively short, t_e=43 days, the lightcurve
displays deviations consistent with parallax effects due to the Earth's
accelerated motion. We show that the chi^2 surface has four distinct local
minima that are induced by the ``jerk-parallax'' degeneracy, with pairs of
solutions having projected Einstein radii, \tilde r_e = 1.76 AU and 1.28 AU,
respectively. This is the second event displaying such a degeneracy and the
first toward the Galactic bulge. For both events, the jerk-parallax formalism
accurately describes the offsets between the different solutions, giving hope
that when extra solutions exist in future events, they can easily be found.
However, the morphologies of the chi^2 surfaces for the two events are quite
different, implying that much remains to be understood about this degeneracy.Comment: 19 pages, 3 figures, 1 table, ApJ, in press, 1 July 200
Probing the atmosphere of a solar-like star by galactic microlensing at high magnification
We report a measurement of limb darkening of a solar-like star in the very
high magnification microlensing event MOA 2002-BLG-33. A 15 hour deviation from
the light curve profile expected for a single lens was monitored intensively in
V and I passbands by five telescopes spanning the globe. Our modelling of the
light curve showed the lens to be a close binary system whose centre-of-mass
passed almost directly in front of the source star. The source star was
identified as an F8-G2 main sequence turn-off star. The measured stellar
profiles agree with current stellar atmosphere theory to within ~4% in two
passbands. The effective angular resolution of the measurements is <1
micro-arcsec. These are the first limb darkening measurements obtained by
microlensing for a Solar-like star.Comment: Accepted for publication in A&A Letters. 5 pages, 2 embedded colour
ps figures plus 1 jpg figure. Version with all figures embedded available
from: http://www.roe.ac.uk/~iab/moa33paper
Improving the Prospects for Detecting Extrasolar Planets in Gravitational Microlensing in 2002
Gravitational microlensing events of high magnification have been shown to be
promising targets for detecting extrasolar planets. However, only a few events
of high magnification have been found using conventional survey techniques.
Here we demonstrate that high magnification events can be readily found in
microlensing surveys using a strategy that combines high frequency sampling of
target fields with online difference imaging analysis. We present 10
microlensing events with peak magnifications greater than 40 that were detected
in real-time towards the Galactic Bulge during 2001 by MOA. We show that Earth
mass planets can be detected in future events such as these through intensive
follow-up observations around the event peaks. We report this result with
urgency as a similar number of such events are expected in 2002.Comment: 11 pages, 3 embedded ps figures including 2 colour, revised version
accepted by MNRA
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