Rotor Spectra, Berry Phases, and Monopole Fields: from Antiferromagnets to QCD

The order parameter of a finite system with a spontaneously broken continuous global symmetry acts as a quantum mechanical rotor. Both antiferromagnets with a spontaneously broken $SU(2)_s$ spin symmetry and massless QCD with a broken $SU(2)_L \times SU(2)_R$ chiral symmetry have rotor spectra when considered in a finite volume. When an electron or hole is doped into an antiferromagnet or when a nucleon is propagating through the QCD vacuum, a Berry phase arises from a monopole field and the angular momentum of the rotor is quantized in half-integer units.Comment: 4 page

Precision multi-epoch astrometry with VLT cameras FORS1/2

We investigate the astrometric performance of the FORS1 and FORS2 cameras of the VLT at long time scales with emphasis on systematic errors which normally prevent attainning a precision better than 1mas. The study is based on multi- epoch time series of observations of a single sky region imaged with a time spacing of 2-6 years at FORS1 and 1-5 months at FORS2. We performed a detailed analysis of a random error of positions that was shown to be dominated by the uncertainty of the star photocenter determination. The component of the random error corresponding to image motion was found to be caused primarily by optical aberrations and variations of atmospheric PSF size but not by the effect of atmospheric image motion. Comparison of observed and model annual/monthly epoch average positions yielded estimates of systematic errors for which temporal properties and distribution in the CCD plane are given. At frame center, the systematic component is about 25 mu-as. Systematic errors are shown to be caused mainly by a combined effect of the image asymmetry and seeing variations which therefore should be strongly limited to avoid generating random and systematic errors. For a series of 30 images, we demonstrated presicion of about 50 mu-as stable on daily, monthly, and annual time scales. Relative proper motion and trigonometric parallaxes of stars in the center of the test field were derived with a precision of 20 mu-as/yr and 40 mu-as for 17-19 mag stars.Comment: 16 pages, 16 figures, 4 tables, accepted in A&A; typos and language corrections; version sent to the printe

Extrasolar planets and brown dwarfs around A-F type stars. II. A planet found with ELODIE around the F6V star HD 33564

We present here the detection of a planet orbiting around the F6V star HD 33564. The radial velocity measurements, obtained with the ELODIE echelle spectrograph at the Haute-Provence Observatory, show a variation with a period of 388 days. Assuming a primary mass of 1.25 Mo, the best Keplerian fit to the data leads to a minimum mass of 9.1 MJup for the companion.Comment: 5 pages. Final version, accepted for publication (A&A). Some Spitzer results on HD33564 (taken this year; not yet published), finally show that the detection of IR excess around this star (by IRAS) is spuriou

Walking near a Conformal Fixed Point: the 2-d O(3) Model at theta near pi as a Test Case

Slowly walking technicolor models provide a mechanism for electroweak symmetry breaking whose nonperturbative lattice investigation is rather challenging. Here we demonstrate walking near a conformal fixed point considering the 2-d lattice O(3) model at vacuum angle $\theta \approx \pi$. The essential features of walking technicolor models are shared by this toy model and can be accurately investigated by numerical simulations. We show results for the running coupling and the beta-function and we perform a finite size scaling analysis of the massgap close to the conformal point.Comment: 5 pages, 4 figure

Binary mixtures of condensates in generic confining potentials

We study a binary mixture of Bose-Einstein condensates, confined in a generic potential, in the Thomas-Fermi approximation. We search for the zero-temperature ground state of the system, both in the case of fixed numbers of particles and fixed chemical potentials.Comment: 20 pages, 2 figure

Standardizing Markers to Evaluate and Compare their Performances

Introduction: Markers that purport to distinguish subjects with a condition from those without a condition must be evaluated rigorously for their classification accuracy. A single approach to statistically evaluating and comparing markers is not yet established. Methods: We suggest a standardization that uses the marker distribution in unaffected subjects as a reference. For an affected subject with marker value Y, the standardized placement value is the proportion of unaffected subjects with marker values that exceed Y. Results: We apply the standardization to two illustrative datasets. In patients with pancreatic cancer placement values calculated for the CA 19-9 marker are smaller than for the CA-125 marker, indicating that CA19-9 is a better marker. For detecting hearing impairment, the placement values for the test output (the marker) are smaller when the input sound stimulus is of lower intensity. This indicates that the test better distinguishes hearing impaired from unimpaired ears when a lower intensity sound stimulus is used. Explicit connections are drawn between the distribution of standardized marker values and the receiver operating characteristic (ROC) curve, one established statistical technique for evaluating classifiers. Discussion: The standardization is an intuitive procedure for evaluating markers. It facilitates direct and meaningful comparisons between markers. It also provides a new view of ROC analysis that may render it more accessible to those as yet unfamiliar with it. The general approach provides a mechanism to statistically address important questions that are typically not addressed in current marker research, such as quantifying and controlling for covariate effects

Arthroscopic transosseous rotator cuff repair: A prospective study on cost savings, surgical time, and outcomes

Objectives: Health expenditures in the United States are outpacing national income, and affordability has become a major policy issue. Over 500,000 rotator cuff repairs (RCR) are performed annually in the United States making RCR a potential source of cost savings. Arthroscopic trans-osseous equivalent (TOE) repair using a double row of anchors has shown superior biomechanical strength compared to other techniques, but at a higher cost. The arthroscopic transosseous (TO) repair is a novel technique allowing arthroscopic rotator cuff repair to be performed without suture anchors. Arthroscopic TO repair may be a means to provide similarly excellent patient outcomes while lowering the cost of care. The primary purpose is to compare the price differential and time of surgery for an arthroscopic rotator cuff repair using anchorless TO repair verses an anchor trans-osseous equivalent (TOE) repair. A secondary purpose of the study was to evaluate outcomes at 6 months postoperatively. Methods: A prospective, case-controlled study evaluating arthroscopic rotator cuff repair using two techniques was performed. The study group consisting of 21 patients undergoing TO repair was compared to a control group consisting of 22 patients undergoing TOE repair. The groups were controlled for size of tear, biceps treatment, acromioplasty, distal clavicle excision, and labral pathology. The primary outcome measures were surgical time as well as total cost of implants and equipment for each surgery, determined by an independent third party, Atlanticare Hospital. Secondary outcomes were changes in the SST, VAS, and SANE scores. Results: Mean total surgical implant/equipment cost per procedure for TOE repair was $2348.03 (SD 490.30) and for TO repair was$1204.97 (SD 330.69; p\u3c0.0001). Mean cut to close time for TOE repair was 85 minutes (95% CI is 77-90) verses 74 (95% CI = 71-98) for TO repair. A log rank test revealed no difference in time (p =0.95). A linear regression model was developed to evaluate the change in SST, VAS, and SANE scores from pre-op to 6 months follow-up. Our study was underpowered but no difference in outcome was observed. Conclusion: Arthroscopic TO rotator cuff repair is a cost savings and time neutral technique compared to TOE repair. A mean of $1100 can be saved in surgical cost per case. In a country that performs over 500,000 RCRs annually, utilizing a TO repair technique can provide substantial cost savings to the healthcare system. © The Author(s) 2015

WAVE-CUSUM: Improving CUSUM performance in network anomaly detection by means of wavelet analysis

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