21 research outputs found
Granular Effect on Electron Conduction in Discontinuous Metal Films
We reanalyze the seminal work by Dolan and Osheroff [Phys. Rev. Lett.
, 721 (1979)] which reported anomalous low-temperature conduction
of high-resistivity thin-film metal strips. We argue that the observed
logarithmic increase of resistance with decreasing temperature in their
3-nm-thick Au-Pd strips be ascribed to the granularity effect on electron
conduction in discontinuous metal films. This reanalysis is further supported
by our measurements on conducting Pb(SiO) nanogranular films,
where is the volume fraction of Pb.Comment: 7 pages, 2 figure
Two-Channel Kondo Effects in Al/AlO/Sc Planar Tunnel Junctions
We have measured the differential conductances in several
Al/AlO/Sc planar tunnel junctions between 2 and 35 K. As the temperature
decreases to 16 K, the zero-bias conductance crosses over from
a standard ln dependence to a novel dependence.
Correspondingly, the finite bias conductance reveals a two-channel
Kondo scaling behavior between 4 and 16 K. The observed two-channel
Kondo physics is ascribed to originating from a few localized spin- Sc
atoms situated slightly inside the AlO/Sc interface.Comment: 4 pages, 3 figures. Phys. Rev. B (accepted
Predicting Hospital-Acquired Infections by Scoring System with Simple Parameters
BACKGROUND: Hospital-acquired infections (HAI) are associated with increased attributable morbidity, mortality, prolonged hospitalization, and economic costs. A simple, reliable prediction model for HAI has great clinical relevance. The objective of this study is to develop a scoring system to predict HAI that was derived from Logistic Regression (LR) and validated by Artificial Neural Networks (ANN) simultaneously. METHODOLOGY/PRINCIPAL FINDINGS: A total of 476 patients from all the 806 HAI inpatients were included for the study between 2004 and 2005. A sample of 1,376 non-HAI inpatients was randomly drawn from all the admitted patients in the same period of time as the control group. External validation of 2,500 patients was abstracted from another academic teaching center. Sixteen variables were extracted from the Electronic Health Records (EHR) and fed into ANN and LR models. With stepwise selection, the following seven variables were identified by LR models as statistically significant: Foley catheterization, central venous catheterization, arterial line, nasogastric tube, hemodialysis, stress ulcer prophylaxes and systemic glucocorticosteroids. Both ANN and LR models displayed excellent discrimination (area under the receiver operating characteristic curve [AUC]: 0.964 versus 0.969, pβ=β0.507) to identify infection in internal validation. During external validation, high AUC was obtained from both models (AUC: 0.850 versus 0.870, pβ=β0.447). The scoring system also performed extremely well in the internal (AUC: 0.965) and external (AUC: 0.871) validations. CONCLUSIONS: We developed a scoring system to predict HAI with simple parameters validated with ANN and LR models. Armed with this scoring system, infectious disease specialists can more efficiently identify patients at high risk for HAI during hospitalization. Further, using parameters either by observation of medical devices used or data obtained from EHR also provided good prediction outcome that can be utilized in different clinical settings