Academic Priority: Graduate/Doctoral Research

Overview Doctoral Education at UNO: Past, Present, and Future

Magnetic anisotropy and phase transitions in single-crystal Tb5(Si2.2Ge1.8)

The Tb5(SixGe4−x) alloy system has many features in common with the Gd5(SixGe4−x)system although it has a more complex magnetic and structural phase diagram. This paper reports on the magnetic anisotropy and magnetic phase transition of single-crystalTb5(Si2.2Ge1.8) which has been investigated by the measurements of M-H and M-T along the a, b, and c axes. The variation of 1/χ vs T indicates that there is a transition from paramagnetic to ferromagnetic at Tc = 110 K. Below this transition temperature M-Hcurves show very strong anisotropy, and it is believed that this is due to the complex spin configuration. M-H measurements at T = 110 K show that the a axis is the easy axis, and that the saturation magnetization is 200 emu/g. The b axis is the hard axis, which needs an external magnetic field much higher than 2 T to saturate the magnetization in that direction, indicating a high magnetocrystalline anisotropy. The c axis is of intermediate hardness. The magnetic properties of this material are therefore very different from those of the related Gd5Si2Ge2 system, in which the b axis was found to be the easy axis and the magnitude of the anisotropy was smaller

Variation of magnetostriction with temperature in Tb5Si2.2Ge1.8 single crystal

The Tb5(SixGe4−x) alloy system is similar to the better known Gd5(SixGe4−x), except it has a more complex magnetic and structural phase diagram. Gd5(SixGe1−x)4 has received much attention recently due to its giant magnetocaloric effect, colossal magnetostriction and giant magnetoresistance in the vicinity of a first order combined magnetic-structural phase transition. The magnetostriction changes that accompany the phase transitions of single crystal Tb5(Si2.2Ge1.8) have been investigated at temperatures between 20 and150 K by measurements of magnetostriction along the a axis. Over this temperature range the shape and slope of the magnetostriction curves change, indicative of changes in the magnetic state, crystal structure, and magnetic anisotropy. The results appear to indicate a phase transition that occurs near 106 K (onset-completion range of 116–100 K). The steepness of the strain transition, its unusual hysteresis, and its temperature dependence appear to indicate a first order phase transition which is activated by applied magnetic field in addition to temperature (see Fig. 1). Magnetostriction measurements at temperature below the transition region appear to indicate a magnetostriction of small overall magnitude (about 30×10−6) but high anisotropy, with anistropy showing considerable temperature dependence

Estimating the Contribution of Point Sources to Atmospheric Metals Using Single-particle Mass Spectrometry

Single-particle mass spectra were collected using an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) during December of 2003 and February of 2004 at an industrially impacted location in East St. Louis, IL. Hourly integrated peak areas for twenty ions were evaluated for their suitability in representing metals/metalloids, particularly those reported in the US EPA Toxic Release Inventory (TRI). Of the initial twenty ions examined, six (Al, As, Cu, Hg, Ti, and V) were found to be unsuitable due to strong isobaric interferences with commonly observed organic fragments, and one (Be) was found to have no significant signal. The usability of three ions (Co, Cr, and Mn) was limited due to suspected isobaric interferences based on temporal comparisons with commonly observed organic fragments. The identity of the remaining ions (Sb, Ba, Cd, Ca, Fe, Ni, Pb, K, Se, and Zn) was substantiated by comparing their signals with the integrated hourly signals of one or more isotope ions. When compared with one-in-six day integrated elemental data as determined by X-ray fluorescence spectroscopy (XRF), the daily integrated ATOFMS signal for several metal ions revealed a semi-quantitative relationship between ATOFMS peak area and XRF concentrations, although in some cases comparison of these measurements were poor at low elemental concentrations/ion signals due to isobaric interferences. A method of estimating the impact of local point sources was developed using hourly integrated ATOFMS peak areas, and this method attributed as much as 85% of the concentration of individual metals observed at the study site to local point sources. Hourly surface wind data were used in conjunction with TRI facility emissions data to reveal likely point sources impacting metal concentrations at the study site and to illustrate the utility of using single-particle mass spectral data to characterize atmospheric metals and identify point sources

The Moral of the Tale: Stories, Trust, and Public Engagement with Clinical Ethics via Radio and Theatre.

Trust is frequently discussed with reference to the professional-patient relationship. However, trust is less explored in relation to the ways in which understanding of, and responses to, questions of ethics are discussed by both the "public" and "experts." Public engagement activity in healthcare ethics may invoke "trust" in analysing a moral question or problem but less frequently conceives of trust as integral to "public engagement" itself. This paper explores the relationship between trust and the ways in which questions of healthcare ethics are identified and negotiated by both "experts" and the public. Drawing on two examples from the author's "public engagement" work-a radio programme for the British Broadcasting Corporation and work with a playwright and theatre-the paper interrogates the ways in which "public engagement" is often characterized. The author argues that the common approach to public engagement in questions of ethics is unhelpfully constrained by a systemic disposition which continues to privilege the professional or expert voice at the expense of meaningful exchange and dialogue. By creating space for novel interactions between the "expert" and the "public," authentic engagement is achieved that enables not only the participants to flourish but also contributes to trust itself

Variation in use of surveillance colonoscopy among colorectal cancer survivors in the United States

<p>Abstract</p> <p>Background</p> <p>Clinical practice guidelines recommend colonoscopies at regular intervals for colorectal cancer (CRC) survivors. Using data from a large, multi-regional, population-based cohort, we describe the rate of surveillance colonoscopy and its association with geographic, sociodemographic, clinical, and health services characteristics.</p> <p>Methods</p> <p>We studied CRC survivors enrolled in the Cancer Care Outcomes Research and Surveillance (CanCORS) study. Eligible survivors were diagnosed between 2003 and 2005, had curative surgery for CRC, and were alive without recurrences 14 months after surgery with curative intent. Data came from patient interviews and medical record abstraction. We used a multivariate logit model to identify predictors of colonoscopy use.</p> <p>Results</p> <p>Despite guidelines recommending surveillance, only 49% of the 1423 eligible survivors received a colonoscopy within 14 months after surgery. We observed large regional differences (38% to 57%) across regions. Survivors who received screening colonoscopy were more likely to: have colon cancer than rectal cancer (OR = 1.41, 95% CI: 1.05-1.90); have visited a primary care physician (OR = 1.44, 95% CI: 1.14-1.82); and received adjuvant chemotherapy (OR = 1.75, 95% CI: 1.27-2.41). Compared to survivors with no comorbidities, survivors with moderate or severe comorbidities were less likely to receive surveillance colonoscopy (OR = 0.69, 95% CI: 0.49-0.98 and OR = 0.44, 95% CI: 0.29-0.66, respectively).</p> <p>Conclusions</p> <p>Despite guidelines, more than half of CRC survivors did not receive surveillance colonoscopy within 14 months of surgery, with substantial variation by site of care. The association of primary care visits and adjuvant chemotherapy use suggests that access to care following surgery affects cancer surveillance.</p

Genome sequences of four cluster P mycobacteriophages

Four bacteriophages infecting Mycobacterium smegmatis mc2155 (three belonging to subcluster P1 and one belonging to subcluster P2) were isolated from soil and sequenced. All four phages are similar in the left arm of their genomes, but the P2 phage differs in the right arm. All four genomes contain features of temperate phages

Placing the library at the heart of plagiarism prevention: The University of Bradford experience.

yesPlagiarism is a vexed issue for Higher Education, affecting student transition, retention and attainment. This paper reports on two initiatives from the University of Bradford library aimed at reducing student plagiarism. The first initiative is an intensive course for students who have contravened plagiarism regulations. The second course introduces new students to the concepts surrounding plagiarism with the aim to prevent plagiarism breaches. Since the Plagiarism Avoidance for New Students course was introduced there has been a significant drop in students referred to the disciplinary programme. This paper discusses the background to both courses and the challenges of implementation