Precision Pion-Proton Elastic Differential Cross Sections at Energies Spanning the Delta Resonance

A precision measurement of absolute pi+p and pi-p elastic differential cross sections at incident pion laboratory kinetic energies from T_pi= 141.15 to 267.3 MeV is described. Data were obtained detecting the scattered pion and recoil proton in coincidence at 12 laboratory pion angles from 55 to 155 degrees for pi+p, and six angles from 60 to 155 degrees for pi-p. Single arm measurements were also obtained for pi+p energies up to 218.1 MeV, with the scattered pi+ detected at six angles from 20 to 70 degrees. A flat-walled, super-cooled liquid hydrogen target as well as solid CH2 targets were used. The data are characterized by small uncertainties, ~1-2% statistical and ~1-1.5% normalization. The reliability of the cross section results was ensured by carrying out the measurements under a variety of experimental conditions to identify and quantify the sources of instrumental uncertainty. Our lowest and highest energy data are consistent with overlapping results from TRIUMF and LAMPF. In general, the Virginia Polytechnic Institute SM95 partial wave analysis solution describes our data well, but the older Karlsruhe-Helsinki PWA solution KH80 does not.Comment: 39 pages, 22 figures (some with quality reduced to satisfy ArXiv requirements. Contact M.M. Pavan for originals). Submitted to Physical Review

EXAFS study of graphite intercalation compounds with transition metals (Fe, Ni)

Graphite intercalation compounds with Fe and Ni have been investigated by means of EXAFS spectroscopy. Iron atoms have been shown to form π-type complexes where the carbon net acts as a polydentate aromatic ligand. In contrast, nickel atoms form two-dimensional monolayers with close-packed hexagonal structure.Les composds d'insertion du graphite avec le Fe et Ni ont été étudiés par EXAFS. On montre que les atomes de fer forment des complexes de type π ou le réseau de carbone joue le rôle d'un ligand aromatique polydentate. Par contre, les atomes de nickel forment des monocouches bidimensionnelles dans un arrangement hexagonal compact

The accuracy of clinical diagnosis of onychomycosis in Dutch general practice: a diagnostic accuracy study

Background: Onychomycosis, the most common cause of nail dystrophy, is generally diagnosed by clinical examination. Current guidelines for Dutch general practice advise confirmatory testing only in cases of doubt or insufficient response to treatment. However, making a correct diagnosis can be challenging given the wide variety of clinical features and differential diagnosis. Aim: To establish accuracy of clinical diagnosis of onychomycosis by GPs. Design & setting: A diagnostic accuracy study based on GPs' clinical diagnosis of primary care patients suspected of onychomycosis. Method: Using 137 complete datasets from the Onycho Trial, diagnostic accuracy of clinical diagnosis as the index test was compared with confirmatory testing as the reference test. A sensitivity analysis was performed to determine diagnostic values for different combinations of index and reference test. Logistical regression was used to assess which clinical characteristics were associated with the positive predictive value (PPV) of the index test. Results: Clinical accuracy, that is the PPV of the index test, was 74.5%. Sensitivity analysis showed no significant difference in diagnostic values. Male sex and a history of any previous treatment significantly increased clinical accuracy with an odds ratio (OR) of 3.873 (95% confidence interval [CI] = 1.230 to 12.195, P = 0.021) and OR 4.022 (95% CI = 1.075 to 15.040, P = 0.039), respectively. Conclusion: The study demonstrated that the GPs' clinical diagnosis of onychomycosis was insufficiently accurate to initiate treatment without confirmatory testing. Further research is needed to investigate how to increase clinical accuracy and reduce potentially unnecessary exposure to treatment.Dermatology-oncolog

Creating design guidelines for a navigational aid for mild demented pedestrians

In this paper we describe our project in which we study design options for a GPS-based navigation aid for elderly with beginning dementia. In a user centered approach we first studied problems of the target group. Results were used in the design of a WoZ prototype. The method proved to work very well in designing a prototype that is tuned to the needs of the user. This prototype was used in experiments in which we studied the performance of landmark vs. left right instructions in navigation. We found that landmark based instructions resulted in less errors and less hesitation with the users