Glaciology of the Queen Maud Land Traverse, 1964-65 South Pole - Pole of Relative Inaccessibility

The University Archives has determined that this item is of continuing value to OSU's history.An oversnow traverse was made from the South Pole to the Pole of Relative Inaccessibility along a zigzag path of about 800 nautical miles during the period 4 December 1964 to 27 January 1965. The surface varied from very hard with many highly developed sastrugi to very soft and smooth. The average air temperature was -28.8°C, with an absolute maximum of -l8.2°C on 5 January and an absolute minimum of -44.7°C on 26 January. The absolute maximum wind speed recorded was 9.0 m/s on 29 December and 17 January; there was 3 percent calm in December and 1 percent calm in January. Solar halos were frequent. Firn temperatures were taken at 29 sites; the most striking anomaly occurred on the last leg of the traverse where there was an abrupt change in slope and as the height increased the temperature anomalously increased before decreasing as expected. The temperature profile at the Pole of Inaccessibility was similar to that obtained by the Soviets in 1964. Temperature gradients were negative at the South Pole but strikingly positive in the vicinity of the Pole of Inaccessibility. Density profiles to depths of 40 m were taken at 12 sites with a neutron-scattering device; most of the density curves showed a break at a density of 0.52 to 0.54 g/cm3. Snow accumulation studies in pits showed an accumulation generally between 5 and 10g/cm2. Snow accumulation measured at the anemometer mast and the instrument shelter at the Pole of Inaccessibility for the period 14 December 1958 to 30 January 1965 was 3-6 g/cm2/yr.National Science Foundation NSF Grant GA-13

Exposure-Lag-Response in Longitudinal Studies: Application of Distributed-Lag Nonlinear Models in an Occupational Cohort.

Prolonged exposures can have complex relationships with health outcomes, as timing, duration, and intensity of exposure are all potentially relevant. Summary measures such as cumulative exposure or average intensity of exposure may not fully capture these relationships. We applied penalized and unpenalized distributed-lag nonlinear models (DLNMs) with flexible exposure-response and lag-response functions in order to examine the association between crystalline silica exposure and mortality from lung cancer and nonmalignant respiratory disease in a cohort study of 2,342 California diatomaceous earth workers followed during 1942-2011. We also assessed associations using simple measures of cumulative exposure assuming linear exposure-response and constant lag-response. Measures of association from DLNMs were generally higher than those from simpler models. Rate ratios from penalized DLNMs corresponding to average daily exposures of 0.4 mg/m3 during lag years 31-50 prior to the age of observed cases were 1.47 (95% confidence interval (CI): 0.92, 2.35) for lung cancer mortality and 1.80 (95% CI: 1.14, 2.85) for nonmalignant respiratory disease mortality. Rate ratios from the simpler models for the same exposure scenario were 1.15 (95% CI: 0.89, 1.48) and 1.23 (95% CI: 1.03, 1.46), respectively. Longitudinal cohort studies of prolonged exposures and chronic health outcomes should explore methods allowing for flexibility and nonlinearities in the exposure-lag-response

Screening for Latent Tuberculosis Infection among Students of Healthcare Professions and Postgraduates of the Faculty of Medicine of the University of Palermo

Introduction and objective: Italy is a country with a low incidence of tuberculosis and in the last fifty years the annual number of TB cases decreased from 12,247 to 4,418, showing a reduction of approximately 64% in the number of cases and 71% in incidence. Despite of this encouraging trend, in the last years the epidemiology of tuberculosis changed and today it is a re-emerging infectious. The aim of this study is to measure the prevalence of positivity to tuberculosis infection (latent TB) in students, without any obvious manifestation of disease, attending degree courses of the health care professions and postgraduate medical courses of the School of Medicine of the University of Palermo, Italy. Materials and methods: A cross-sectional observational study in students of nursing, midwifery, dentistry degree courses and in resident physicians of postgraduate medical schools was carried out from January 2012 to July 2016. Mantoux test was performed and all positive cases were tested with Interferon-Gamma Release Assay (IGRA). Results: Of the 1,351 subjects evaluated, 25 (1.8%) resulted positive to Mantoux test; in 17 students (1.2%) the diagnosis was confirmed with IGRA. Positive cases were significantly more frequent among students attending Postgraduated Medical School Courses (p<0.001) and were older than negative cases (p<0.001). Conclusion: This study suggests that in our geographic area, latent TB shows a relatively low prevalence among students of medical schools. Despite of this evidence, and considering that several students have been found to be positive for TB, this infectious disease has to be considered a re-emerging biohazard that requires preventive strategies for the containment of the risk in exposed workers as well as in the general population

The CP-violating asymmetry in \eta\to\pi^+ \pi^- e^+e^-

We study the CP-violating asymmetry {\cal A}_{\rm CP}, which arises, in \eta\to\pi^+\pi^- e^+e^-, from the angular correlation of the e^+ e^- and \pi^+\pi^- planes due to the interference between the magnetic and electric decay amplitudes. With the phenomenologically determined magnetic amplitude and branching ratio as input, the asymmetry, induced by the electric bremsstrahlung amplitude through the CP-violating decay \eta\to\pi^+\pi^-, and by an unconventional tensor type operator, has been estimated respectively. The upper bound of {\cal A}_{\rm CP} from the former is about 10^{-3}, and the asymmetry from the latter might be up to O(10^{-2}). One can therefore expect that this CP asymmetry would be an interesting CP-violating observable for the future precise measurements in the \eta factories.Comment: LaTeX, 6 pages. One reference corrected, and some new references adde

Ischemic cardiovascular disease in workers occupationally exposed to urban air pollution – A systematic review

Introduction. Cardiovascular disease is the first cause of morbidity and mortality worldwide. Among several known risk factors, researchers also focus their attention on the chronic exposure to air pollution. There is much evidence that exposure to air pollution, especially to ultrafine particles, can damage the endothelium and can favour cardiovascular diseases in the general population. Occupational exposition could be an additive risk factor for the cardiovascular system. This article presents a scientific review of the linkage between occupational exposure to air pollution and ischemic heart disease. Materials and method. A scientific review was undertaken, followed by PRISMA Statements. Observational studies were selected from several scientific databases, likesuch as Pubmed, Google Scholar, Nioshtic-2 and Reserchgate, searching for selected key words: police workers, professional drivers, mail carriers, filling station attendants, road cleaners, garage workers, motor vehicles and engine maintenance. All the key words were combined with “Boolean Operators” with the following words: cardiovascular (or cardiac) disease, cardiovascular function, cardiovascular system, ischemic heart disease, coronary disease, myocardial infarction. During the systematic research, the focus was on retrospective and prospective studies from January 1990 – December 2014. Results. Both the retrospective and prospective studies showed an increased risk of ischemic heart disease in occupationally occupied people exposed to air pollution. Only one study presented a ly minor risk. Conclusions. The findings of this systematic review suggest a possible linkage between occupational exposure to urban air pollution, especially to motor exhaust and particulate, and ischemic heart disease

A procedure to characterize geographic distributions of rare disorders in cohorts

<p>Abstract</p> <p>Background</p> <p>Individual point data can be analyzed against an entire cohort instead of only sampled controls to accurately picture the geographic distribution of populations at risk for low prevalence diseases. Analyzed as individual points, many smaller clusters with high relative risks (RR) and low empirical p values are indistinguishable from a random distribution. When points are aggregated into areal units, small clusters may result in a larger cluster with a low RR or be lost if divided into pieces included in units of larger populations that show no increased prevalence. Previous simulation studies showed lowered validity of spatial scan tests for true clusters with low RR. Using simulations, this study explored the effects of low cluster RR and areal unit size on local area clustering test (LACT) results, proposing a procedure to improve accuracy of cohort spatial analysis for rare events.</p> <p>Results</p> <p>Our simulations demonstrated the relationship of true RR to observed RR and p values with various, randomly located, cluster shapes, areal unit sizes and scanning window shapes in a diverse population distribution. Clusters with RR < 1.7 had elevated observed RRs and high p values.</p> <p>We propose a cluster identification procedure that applies parallel multiple LACTs, one on point data and three on two distinct sets of areal units created with varying population parameters that minimize the range of population sizes among units. By accepting only clusters identified by all LACTs, having a minimum population size, a minimum relative risk and a maximum p value, this procedure improves the specificity achieved by any one of these tests alone on a cohort study of low prevalence data while retaining sensitivity for small clusters. The procedure is demonstrated on two study regions, each with a five-year cohort of births and cases of a rare developmental disorder.</p> <p>Conclusion</p> <p>For truly exploratory research on a rare disorder, false positive clusters can cause costly diverted research efforts. By limiting false positives, this procedure identifies 'crude' clusters that can then be analyzed for known demographic risk factors to focus exploration for geographically-based environmental exposure on areas of otherwise unexplained raised incidence.</p

Colored noise in the fractional Hall effect: duality relations and exact results

We study noise in the problem of tunneling between fractional quantum Hall edge states within a four probe geometry. We explore the implications of the strong-weak coupling duality symmetry existent in this problem for relating the various density-density auto-correlations and cross-correlations between the four terminals. We identify correlations that transform as either ``odd'' or ``anti-symmetric'', or ``even'' or ``symmetric'' quantities under duality. We show that the low frequency noise is colored, and that the deviations from white noise are exactly related to the differential conductance. We show explicitly that the relationship between the slope of the low frequency noise spectrum and the differential conductance follows from an identity that holds to {\it all} orders in perturbation theory, supporting the results implied by the duality symmetry. This generalizes the results of quantum supression of the finite frequency noise spectrum to Luttinger liquids and fractional statistics quasiparticles.Comment: 14 pages, 3 figure

An Electronic Mach-Zehnder Interferometer

Double-slit electron interferometers, fabricated in high mobility two-dimensional electron gas (2DEG), proved to be very powerful tools in studying coherent wave-like phenomena in mesoscopic systems. However, they suffer from small fringe visibility due to the many channels in each slit and poor sensitivity to small currents due to their open geometry. Moreover, the interferometers do not function in a high magnetic field, namely, in the quantum Hall effect (QHE) regime, since it destroys the symmetry between left and right slits. Here, we report on the fabrication and operation of a novel, single channel, two-path electron interferometer that functions in a high magnetic field. It is the first electronic analog of the well-known optical Mach-Zehnder (MZ) interferometer. Based on single edge state and closed geometry transport in the QHE regime the interferometer is highly sensitive and exhibits very high visibility (62%). However, the interference pattern decays precipitously with increasing electron temperature or energy. While we do not understand the reason for the dephasing we show, via shot noise measurement, that it is not a decoherence process that results from inelastic scattering events.Comment: to appear in Natur