First Results from SPARO: Evidence for Large-Scale Toroidal Magnetic Fields in the Galactic Center

We have observed the linear polarization of 450 micron continuum emission from the Galactic center, using a new polarimetric detector system that is operated on a 2 m telescope at the South Pole. The resulting polarization map extends ~ 170 pc along the Galactic plane and ~ 30 pc in Galactic latitude, and thus covers a significant fraction of the central molecular zone. Our map shows that this region is permeated by large-scale toroidal magnetic fields. We consider our results together with radio observations that show evidence for poloidal fields in the Galactic center, and with Faraday rotation observations. We compare all of these observations with the predictions of a magnetodynamic model for the Galactic center that was proposed in order to explain the Galactic Center Radio Lobe as a magnetically driven gas outflow. We conclude that the observations are basically consistent with the model.Comment: 11 pages, 2 figures, 1 table, submitted to ApJ Let

Postmortem Dental Records Identification by Dental Hygiene Students: A Pilot Study

Purpose: Dental hygienists have the potential for filling critical roles in multidisciplinary victim identification teams. The purpose of this pilot study was to evaluate the accuracy of dental hygiene students utilizing dental charting, bitewings, and skull dentitions for the purpose of making identification matches. Methods: Thirty senior dental hygiene students (n=30) independently viewed an asynchronous online multimedia-based presentation on the procedures used for collecting and recording forensic dental evidence. Following the presentation participants attempted to chart and match three bitewing radiograph sets to three human skull dentitions by correlating matches/exclusions. Immediately following the activity, each student completed a questionnaire rating the difficulty of the exercise, as well as their confidence, and willingness to volunteer as a forensics team member. Descriptive statistics were used to analyze the data. Results: Of the total sample 36.7% (n=11) reported having prior experiences with dental radiography; while the majority (63.33%, n=19) reported no prior experience. Participants\u27 accuracy scores for dental charting ranged from 91.23% (SD=9.42) to 99.06% (SD=3.60), with no statistically significant difference based on prior experience (p\u3e0.05). The average interrater reliability was 86% (p\u3c0.0001), indicating a high level of agreement with charting skulls and radiographs. No statistically significant differences were found for charting time, perceived difficulty, or level of confidence when comparing experience among the participants (p\u3e0.05). Conclusions: Regardless of previous experience, dental hygiene students were able to match postmortem dentitions and radiographs with good interrater reliability and did not differ statistically for charting time, perceived difficulty, or confidence. Results suggest dental hygienists can work as effective victim identification team members when educational programs are implemented

Active Shooter Preparedness Among Dental Hygiene Students

Purpose: Active shooter incidents (ASIs) occurring in dental hygiene academic settings present unique challenges and research examining institutional preparation of dental hygiene students for such incidents is lacking. The purpose of this pilot project was to examine the perceived preparedness, confidence, and awareness of dental hygiene students regarding ASIs. Methods: A validated 24-item electronic survey was distributed to dental hygiene students (n=68) at one institution to measure their preparedness, confidence, and awareness regarding ASIs. Descriptive statistics and Pearson correlations were used for data analysis. Results: Fifty-seven dental hygiene students completed the survey for a response rate of 84%. Many participants felt slightly prepared (n=26, 45.6%) or not prepared (n=15, 26.3%) to respond to an ASI in the classroom. Most were slightly confident (n=26, 45.6%) or not confident (n=16, 26.3%) in helping to control the classroom during an ASI. Over half (n=32, 56.1%) were not certain if their institution provided active shooter trainings and were not certain if drills occurred (n=25,43.8%). Perceived preparedness was positively correlated with confidence in helping to control an ASI in the classroom (r(56)=.616, p=.000). Positive correlations were also identified with perceived preparedness to respond in a lab or clinic with the assumption that ASIs are taken seriously at their institution (r(56)=.375, p=.004). Conclusion: A general lack of preparedness and confidence for responding to ASIs may exist among dental hygiene students along with a lack of awareness regarding trainings and drills. Educational institutions should implement best practices for preparing dental hygiene students for ASIs

The Heider balance - a continuous approach

The Heider balance (HB) is investigated in a fully connected graph of $N$ nodes. The links are described by a real symmetric array r(i,j), i,j=1,...,N. In a social group, nodes represent group members and links represent relations between them, positive (friendly) or negative (hostile). At the balanced state, r(i,j)r(j,k)r(k,i)>0 for all the triads (i,j,k). As follows from the structure theorem of Cartwright and Harary, at this state the group is divided into two subgroups, with friendly internal relations and hostile relations between the subgroups. Here the system dynamics is proposed to be determined by a set of differential equations. The form of equations guarantees that once HB is reached, it persists. Also, for N=3 the dynamics reproduces properly the tendency of the system to the balanced state. The equations are solved numerically. Initially, r(i,j) are random numbers distributed around zero with a symmetric uniform distribution of unit width. Calculations up to N=500 show that HB is always reached. Time to get the balanced state varies with the system size N as N^{-1/2}. The spectrum of relations, initially narrow, gets very wide near HB. This means that the relations are strongly polarized. In our calculations, the relations are limited to a given range around zero. With this limitation, our results can be helpful in an interpretation of somestatistical data.Comment: 9 pages, 4 figures. Int. J. Mod. Phys. C (2005), in prin

A study of anodic films on n-InP by spectroscopic ellipsometry and atomic force microscopy

The growth of anodic films on n-InP in 1 mol dm-1 KOH is investigated under potential sweep conditions. At lower potentials a thin surface film is formed and a peak is observed on the current-voltage curve. Ellipsometric measurements show that this film increases in thickness with increasing potential but the observed thickness values are significantly less than the corresponding coulometrically estimated values. This indicates that much of the charge passed is not involved in the formation of a surface film but presumably in the formation of soluble anodic reaction products. Cyclic voltammograms show that a current peak is also observed on the reverse sweep and ellipsometric measurements show that the anodic film thickness also increases during the reverse sweep until the peak potential is reached. Atomic force microscopy (AFM) shows that the surface becomes smoother as the potential is increased. We attribute this to the formation of nuclei at lower potentials, which coalesce as the layer becomes thicker. Electron diffraction and x-ray photoelectron spectroscopy (XPS) analysis show that the surface film is predominantly In2O3 with no evidence of InPO4

Anisotropy in the Cosmic Microwave Background at Degree Angular Scales: Python V Results

Observations of the microwave sky using the Python telescope in its fifth season of operation at the Amundsen-Scott South Pole Station in Antarctica are presented. The system consists of a 0.75 m off-axis telescope instrumented with a HEMT amplifier-based radiometer having continuum sensitivity from 37-45 GHz in two frequency bands. With a 0.91 deg x 1.02 deg beam the instrument fully sampled 598 deg^2 of sky, including fields measured during the previous four seasons of Python observations. Interpreting the observed fluctuations as anisotropy in the cosmic microwave background, we place constraints on the angular power spectrum of fluctuations in eight multipole bands up to l ~ 260. The observed spectrum is consistent with both the COBE experiment and previous Python results. There is no significant contamination from known foregrounds. The results show a discernible rise in the angular power spectrum from large (l ~ 40) to small (l ~ 200) angular scales. The shape of the observed power spectrum is not a simple linear rise but has a sharply increasing slope starting at l ~ 150.Comment: 5 page

Dental Hygiene and Dental Assistant Students\u27 Simulated DVI Radiographic Match Accuracy: A Pilot Study

Purpose Allied dental health care professionals have served on disaster victim identification (DVI) teams; however, the literature is void of statistical measures regarding transferable skills and disaster preparedness. The purpose of this study was to assess second year dental hygiene and dental assistant students’ match accuracy for simulated DVI radiographs and compare the match accuracy between the student groups. Methods Five patient cases were chosen at random to retrospectively collect sets of digital bitewing radiographs from two time periods. The five retrospectively selected sets of images served as simulated antemortem (AM) and postmortem (PM) radiographs. A convenience sample of second year dental hygiene and dental assistant students from two institutions (n=48) were invited to participate in this IRB-exempt descriptive observational study. The previously selected AM and PM images were randomly mismatched, and participants were asked to visually compare the image sets and indicate the matches using a drag and drop feature in an electronic survey instrument. Descriptive statistics were used to analyze the data; the significance level was set at α=0.05. Results A total of 41 dental hygiene and dental assistant students agreed to participate for a response rate of 85.4%. Eighty-five percent of the participants accurately matched five out of five sets while the remaining 15% accurately matched three out of five sets. A one-sample binomial proportion test revealed that 80% of the participants were able to match at least four out of five sets (p\u3c0.001). Dental hygiene students demonstrated increased matching performance as compared to dental assisting students (p=0.013). Conclusion Both dental hygiene and dental assistant students demonstrated transferable DVI skills to accurately match simulated AM and PM radiographs. Future research is needed in a larger sample to develop and assess best practices of DVI training to build on existing skills for allied dental health care professionals