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Search Results: 1 - 10 of 326859 matches for " John J. Anderson "
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Ankle Arthroscopy, Lateral Ligament Repair and Peroneal Tendon Reefing for Chronic Lateral Ankle Instability: The Triad vs Arthroscopy with Ligament Repair  [PDF]
John J. Anderson, Loren K. Spencer, Zflan Fowler
Surgical Science (SS) , 2015, DOI: 10.4236/ss.2015.69058
Abstract: Peroneal tendon and retinacular pathology contributes to chronic lateral ankle instability. The “gold standard” surgical treatment for chronic lateral ankle instability has been the Brostrom-Gould procedure with its modifications. An ankle arthroscopy is an adjuvant procedure to address any intra-articular pathology. We review our results of two study groups. The first group underwent an ankle arthroscopy and a Brostrom-Gould procedure. The second group (triad) underwent an ankle arthroscopy, the Brostrom-Gould procedure and excision of low lying peroneal muscle belly with tightening of the inferior peroneal retinaculum. The triad technique was performed on 97 patients and results compared to 71 ankle arthroscopies with the Brostrom-Gould procedure. The patients were contacted at a mean follow-up time of 30 months for postoperative ACFAS scores, VAS scores, and overall satisfaction. Patients were also asked to report incidence of ankle sprain recurrence. The average postoperative ACFAS hindfoot and ankle score was 92 for the triad group and 89 for the arthroscopic debridement and Brostrom-Gould group. The average overall satisfaction was 98% in the triad group and 91% in the scope and Brostrom group. There were 4 (4.3%) recurrences in the triad group and 12 (17.6%) in the Brostrom-Gould with scope group. Each group had a similar incidence of wound healing complications. Peroneal tendon and retinacular pathology contributes to continued ankle instability and pain. We believe that the triad procedure is superior to the Brostrom-Gould procedure.
Risk of High Dietary Calcium for Arterial Calcification in Older Adults
John J. B. Anderson,Philip J. Klemmer
Nutrients , 2013, DOI: 10.3390/nu5103964
Abstract: Concern has recently arisen about the potential adverse effects of excessive calcium intakes, i.e., calcium loading from supplements, on arterial calcification and risks of cardiovascular diseases (CVD) in older adults. Published reports that high calcium intakes in free-living adults have relatively little or no beneficial impact on bone mineral density (BMD) and fracture rates suggest that current recommendations of calcium for adults may be set too high. Because even healthy kidneys have limited capability of eliminating excessive calcium in the diet, the likelihood of soft-tissue calcification may increase in older adults who take calcium supplements, particularly in those with age or disease-related reduction in renal function. The maintenance of BMD and bone health continues to be an important goal of adequate dietary calcium consumption, but eliminating potential risks of CVDs from excessive calcium intakes needs to be factored into policy recommendations for calcium by adults.
Chameleon effect and the Pioneer anomaly
John D. Anderson,J. R. Morris
Physics , 2012, DOI: 10.1103/PhysRevD.85.084017
Abstract: The possibility that the apparent anomalous acceleration of the Pioneer 10 and 11 spacecraft may be due, at least in part, to a chameleon field effect is examined. A small spacecraft, with no thin shell, can have a more pronounced anomalous acceleration than a large compact body, such as a planet, having a thin shell. The chameleon effect seems to present a natural way to explain the differences seen in deviations from pure Newtonian gravity for a spacecraft and for a planet, and appears to be compatible with the basic features of the Pioneer anomaly, including the appearance of a jerk term. However, estimates of the size of the chameleon effect indicate that its contribution to the anomalous acceleration is negligible. We conclude that any inverse-square component in the anomalous acceleration is more likely caused by an unmodelled reaction force from solar-radiation pressure, rather than a chameleon field effect.
Localization for Uniform Algebras Generated by Real-Analytic Functions
John T. Anderson,Alexander J. Izzo
Mathematics , 2015,
Abstract: It is shown that if $A$ is a uniform algebra generated by real-analytic functions on a suitable compact subset $K$ of a real-analytic variety such that the maximal ideal space of $A$ is $K$, and every continuous function on $K$ is locally a uniform limit of functions in $A$, then $A=C(K)$. This gives an affirmative answer to a special case of a question from the Proceedings of the Symposium on Function Algebras held at Tulane University in 1965.
A Peak Point Theorem for Uniform Algebras on Real-Analytic Varieties
John T. Anderson,Alexander J. Izzo
Mathematics , 2015, DOI: 10.1007/s00208-015-1224-x
Abstract: It was once conjectured that if $A$ is a uniform algebra on its maximal ideal space $X$, and if each point of $X$ is a peak point for $A$, then $A = C(X)$. This peak-point conjecture was disproved by Brian Cole in 1968. Here we establish a peak-point theorem for uniform algebras generated by real-analytic functions on real-analytic varieties, generalizing previous results of the authors and John Wermer.
Split thickness skin grafts for the treatment of non-healing foot and leg ulcers in patients with diabetes: a retrospective review
John J. Anderson,Kelly J. Wallin,Loren Spencer
Diabetic Foot & Ankle , 2012, DOI: 10.3402/dfa.v3i0.10204
Abstract: We retrospectively reviewed 107 diabetic patients who received a split thickness skin graft (STSG) for treatment of a non-healing diabetic foot or leg ulcer to describe healing times based on patient characteristics, comorbidities or complications. The minimum follow-up was 6 months from the time of STSG application. The mean time to healing among all patients was 5.1 weeks (3 to 16 weeks). The mean healing time for patients with complications was 12.0 weeks (10 to 16 weeks) while the mean healing time for those without complications was 4.9 weeks (3 to 10 weeks). Overall complication rate was 2.8%. Patients with a STSG take of less than 95% had a mean healing time of 7.9 weeks compared to 4.8 weeks for those with a STSG take of 100% (p<0.001). The use of autologous STSG for treatment of non-healing diabetic foot and leg wounds is a viable method for soft tissue closure and may present a low complication rate and a satisfactory rate of healing.
School Consolidation in Nebraska: Economic Efficiency vs. Rural Community Life
Joan M. Blauwkamp,Peter J. Longo,John Anderson
Online Journal of Rural Research & Policy , 2011, DOI: 10.4148/ojrrp.v6i1.1309
Abstract: We examine the factors driving rural school consolidations, focusing our analysis on Nebraska. We consider statutory and case law, the school financing formulas that drive consolidation and the efforts by rural citizens to challenge those financing formulas in courts. We analyze how rural school consolidations have been framed in newspaper coverage, in order to see the dominant understandings of the cost-benefit tradeoffs in consolidating rural schools. Finally, we study three cases of rural Nebraska school districts for the insights these cases provide as to the challenges of sustaining rural community schools and the effects of consolidation on the students and the communities. Our conclusion is that schools play a vital role in sustaining rural community life, although the costs to the community when schools are consolidated are more difficult to quantify than the economies of scale that motivate those consolidations.
Jupiter's Moment of Inertia: A Possible Determination by JUNO
Ravit Helled,John D. Anderson,Gerald Schubert,David J. Stevenson
Physics , 2011, DOI: 10.1016/j.icarus.2011.09.016
Abstract: The moment of inertia of a giant planet reveals important information about the planet's internal density structure and this information is not identical to that contained in the gravitational moments. The forthcoming Juno mission to Jupiter might determine Jupiter's normalized moment of inertia NMoI=C/MR^2 by measuring Jupiter's pole precession and the Lense-Thirring acceleration of the spacecraft (C is the axial moment of inertia, and M and R are Jupiter's mass and mean radius, respectively). We investigate the possible range of NMoI values for Jupiter based on its measured gravitational field using a simple core/envelope model of the planet assuming that J_2 and J_4 are perfectly known and are equal to their measured values. The model suggests that for fixed values of J_2 and J_4 a range of NMOI values between 0.2629 and 0.2645 can be found. The Radau-Darwin relation gives a NMoI value that is larger than the model values by less than 1%. A low NMoI of ~ 0.236, inferred from a dynamical model (Ward & Canup, 2006, ApJ, 640, L91) is inconsistent with this range, but the range is model dependent. Although we conclude that the NMoI is tightly constrained by the gravity coefficients, a measurement of Jupiter's NMoI to a few tenths of percent by Juno could provide an important constraint on Jupiter's internal structure. We carry out a simplified assessment of the error involved in Juno's possible determination of Jupiter's NMoI.
Evidence for Large Temperature Fluctuations in Quasar Accretion Disks From Spectral Variability
John J. Ruan,Scott F. Anderson,Jason Dexter,Eric Agol
Physics , 2014, DOI: 10.1088/0004-637X/783/2/105
Abstract: The well-known bluer-when-brighter trend observed in quasar variability is a signature of the complex processes in the accretion disk, and can be a probe of the quasar variability mechanism. Using a sample of 604 variable quasars with repeat spectra in SDSS-I/II, we construct difference spectra to investigate the physical causes of this bluer-when-brighter trend. The continuum of our composite difference spectrum is well-fit by a power-law, with a spectral index in excellent agreement with previous results. We measure the spectral variability relative to the underlying spectra of the quasars, which is independent of any extinction, and compare to model predictions. We show that our SDSS spectral variability results cannot be produced by global accretion rate fluctuations in a thin disk alone. However, we find that a simple model of a inhomogeneous disk with localized temperature fluctuations will produce power-law spectral variability over optical wavelengths. We show that the inhomogeneous disk will provide good fits to our observed spectral variability if the disk has large temperature fluctuations in many independently varying zones, in excellent agreement with independent constraints from quasar microlensing disk sizes, their strong UV spectral continuum, and single-band variability amplitudes. Our results provide an independent constraint on quasar variability models, and add to the mounting evidence that quasar accretion disks have large localized temperature fluctuations.
Detection of Quasar Feedback from the Thermal Sunyaev-Zel'dovich Effect in Planck
John J. Ruan,Matthew McQuinn,Scott F. Anderson
Physics , 2015, DOI: 10.1088/0004-637X/802/2/135
Abstract: Poorly understood feedback processes associated with highly-luminous black hole accretion in quasars may dramatically affect the properties of their host galaxies. We search for the effect of quasar feedback on surrounding gas using Planck maps of the thermal Sunyaev-Zel'dovich effect (tSZ). By stacking tSZ Compton-y maps centered on the locations of 26,686 spectroscopic quasars from the Sloan Digital Sky Survey, we detect a strong but unresolved tSZ Compton-y signal at >5 sigma significance that likely originates from a combination of virialized halo atmosphere gas and quasar feedback effects. We show that the feedback contribution to our detected quasar tSZ signal is likely to dominate over virialized halo gas by isolating the feedback tSZ component for high- and low-redshift quasars. We find that this quasar tSZ signal also scales with black hole mass and bolometric luminosity, all consistent with general expectations of quasar feedback. We estimate the mean angularly-integrated Compton-y of quasars at z~1.5 to be 3.5x10^-6 Mpc^2, corresponding to mean total thermal energies in feedback and virialized halo gas of 1.1(+/- 0.2) x 10^62 erg, and discuss the implications for quasar feedback. If confirmed, the large total thermal feedback energetics we estimate of 5% (+/-1% statistical uncertainty) of the black hole mass will have important implications for the effects of quasar feedback on the host galaxy, as well as the surrounding intergalactic medium.
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