Tracking Vector Magnetograms with the Magnetic Induction Equation

The differential affine velocity estimator (DAVE) developed in Schuck (2006) for estimating velocities from line-of-sight magnetograms is modified to directly incorporate horizontal magnetic fields to produce a differential affine velocity estimator for vector magnetograms (DAVE4VM). The DAVE4VM's performance is demonstrated on the synthetic data from the anelastic pseudospectral ANMHD simulations that were used in the recent comparison of velocity inversion techniques by Welsch (2007). The DAVE4VM predicts roughly 95% of the helicity rate and 75% of the power transmitted through the simulation slice. Inter-comparison between DAVE4VM and DAVE and further analysis of the DAVE method demonstrates that line-of-sight tracking methods capture the shearing motion of magnetic footpoints but are insensitive to flux emergence -- the velocities determined from line-of-sight methods are more consistent with horizontal plasma velocities than with flux transport velocities. These results suggest that previous studies that rely on velocities determined from line-of-sight methods such as the DAVE or local correlation tracking may substantially misrepresent the total helicity rates and power through the photosphere.Comment: 30 pages, 13 figure

Outcomes of Extravesical Versus Intravesical Ureteral Reimplantation

Purpose: The purpose of our study was to examine outcomes and compare length of stay after extravesical and intravesical ureteral reimplantation at our institution. Materials and Methods: Retrospective review was performed of 30 patients (55 ureters) with vesicoureteral reflux who underwent either the Cohen (intravesical) cross-trigonal procedure or the extravesical (detrusorrhaphy) approach. Each patient had documented follow-up consisting of a postoperative renal ultrasound and/or a voiding cystourethrogram (VCUG). Inclusion criteria was the presence of primary vesicoureteral reflux. Exclusion criteria were patients who had undergone a previous repair and patients in whom results of neither the renal ultrasound nor the VCUG were available. Results: There were no significant cases of obstruction or wound infection with either approach. Two patients who underwent the extravesical approach had persistent reflux on VCUG three months postoperatively, but both resolved by fifteen months. Average length of stay was only 3.00 ± 1.33 days for the extravesical approach, compared to 5.36 ± 1.75 days for the intravesical approach ( P = .0003 ). Conclusions: Given that by fifteen months success rates were the same with either approach, the extravesical approach is comparable to the intravesical technique and is a viable option in terms of outcome and economics given the shorter length of hospital stay

The unique chemistry of Eastern Mediterranean water masses selects for distinct microbial communities by depth

Peer reviewedPublisher PD

Robust Chauvenet Outlier Rejection

Sigma clipping is commonly used in astronomy for outlier rejection, but the number of standard deviations beyond which one should clip data from a sample ultimately depends on the size of the sample. Chauvenet rejection is one of the oldest, and simplest, ways to account for this, but, like sigma clipping, depends on the sample's mean and standard deviation, neither of which are robust quantities: Both are easily contaminated by the very outliers they are being used to reject. Many, more robust measures of central tendency, and of sample deviation, exist, but each has a tradeoff with precision. Here, we demonstrate that outlier rejection can be both very robust and very precise if decreasingly robust but increasingly precise techniques are applied in sequence. To this end, we present a variation on Chauvenet rejection that we call "robust" Chauvenet rejection (RCR), which uses three decreasingly robust/increasingly precise measures of central tendency, and four decreasingly robust/increasingly precise measures of sample deviation. We show this sequential approach to be very effective for a wide variety of contaminant types, even when a significant -- even dominant -- fraction of the sample is contaminated, and especially when the contaminants are strong. Furthermore, we have developed a bulk-rejection variant, to significantly decrease computing times, and RCR can be applied both to weighted data, and when fitting parameterized models to data. We present aperture photometry in a contaminated, crowded field as an example. RCR may be used by anyone at https://skynet.unc.edu/rcr, and source code is available there as well.Comment: 62 pages, 48 figures, 7 tables, accepted for publication in ApJ

Implementing intimate partner violence care in a rural sub-district of South Africa: a qualitative evaluation

Background: Despite a high burden of disease, in South Africa, intimate partner violence (IPV) is known to be poorly recognised and managed. To address this gap, an innovative intersectoral model for the delivery of comprehensive IPV care was piloted in a rural sub-district. Objective: To evaluate the initiative from the perspectives of women using the service, service providers, and managers. Design: A qualitative evaluation was conducted. Service users were interviewed, focus groups were conducted amongst health care workers (HCW), and a focus group and interviews were conducted with the intersectoral implementation team to explore their experiences of the intervention. A thematic analysis approach was used, triangulating the various sources of data. Results: During the pilot, 75 women received the intervention. Study participants described their experience as overwhelmingly positive, with some experiencing improvements in their home lives. Significant access barriers included unaffordable indirect costs, fear of loss of confidentiality, and fear of children being removed from the home. For HCW, barriers to inquiry about IPV included its normalisation in this community, poor understanding of the complexities of living with violence and frustration in managing a difficult emotional problem. Health system constraints affected continuity of care, privacy, and integration of the intervention into routine functioning, and the process of intersectoral action was hindered by the formation of alliances. Contextual factors, for example, high levels of alcohol misuse and socio-economic disempowerment, highlighted the need for a multifaceted approach to addressing IPV. Conclusions: This evaluation draws attention to the need to take a systems approach and focus on contextual factors when implementing complex interventions. The results will be used to inform decisions about instituting appropriate IPV care in the rest of the province. In addition, there is a pressing need for clear policies and guidelines framing IPV as a health issue

Finite pseudo orbit expansions for spectral quantities of quantum graphs

We investigate spectral quantities of quantum graphs by expanding them as sums over pseudo orbits, sets of periodic orbits. Only a finite collection of pseudo orbits which are irreducible and where the total number of bonds is less than or equal to the number of bonds of the graph appear, analogous to a cut off at half the Heisenberg time. The calculation simplifies previous approaches to pseudo orbit expansions on graphs. We formulate coefficients of the characteristic polynomial and derive a secular equation in terms of the irreducible pseudo orbits. From the secular equation, whose roots provide the graph spectrum, the zeta function is derived using the argument principle. The spectral zeta function enables quantities, such as the spectral determinant and vacuum energy, to be obtained directly as finite expansions over the set of short irreducible pseudo orbits.Comment: 23 pages, 4 figures, typos corrected, references added, vacuum energy calculation expande