5,331 research outputs found
Measurement of Lande g factor of 5D5/2 state of BaII with a single trapped ion
We present the first terrestrial measurement of the Lande g factor of the
5D5/2 state of singly ionized barium. Measurements were performed on single
Doppler-cooled 138Ba+ ions in a linear Paul trap. A frequency-stabilized fiber
laser with nominal wavelength 1.762 um was scanned across the 6S1/25D5/2
transition to spectroscopically resolve transitions between Zeeman sublevels of
the ground and excited states. From the relative positions of the four narrow
transitions observed at several different values for the applied magnetic
field, we find a value of 1.2020+/-0.0005 for g of 5D5/2.Comment: 3 figure
Integration of Attributes from Non-Linear Characterization of Cardiovascular Time-Series for Prediction of Defibrillation Outcomes
Objective
The timing of defibrillation is mostly at arbitrary intervals during cardio-pulmonary resuscitation (CPR), rather than during intervals when the out-of-hospital cardiac arrest (OOH-CA) patient is physiologically primed for successful countershock. Interruptions to CPR may negatively impact defibrillation success. Multiple defibrillations can be associated with decreased post-resuscitation myocardial function. We hypothesize that a more complete picture of the cardiovascular system can be gained through non-linear dynamics and integration of multiple physiologic measures from biomedical signals. Materials and Methods
Retrospective analysis of 153 anonymized OOH-CA patients who received at least one defibrillation for ventricular fibrillation (VF) was undertaken. A machine learning model, termed Multiple Domain Integrative (MDI) model, was developed to predict defibrillation success. We explore the rationale for non-linear dynamics and statistically validate heuristics involved in feature extraction for model development. Performance of MDI is then compared to the amplitude spectrum area (AMSA) technique. Results
358 defibrillations were evaluated (218 unsuccessful and 140 successful). Non-linear properties (Lyapunov exponent \u3e 0) of the ECG signals indicate a chaotic nature and validate the use of novel non-linear dynamic methods for feature extraction. Classification using MDI yielded ROC-AUC of 83.2% and accuracy of 78.8%, for the model built with ECG data only. Utilizing 10-fold cross-validation, at 80% specificity level, MDI (74% sensitivity) outperformed AMSA (53.6% sensitivity). At 90% specificity level, MDI had 68.4% sensitivity while AMSA had 43.3% sensitivity. Integrating available end-tidal carbon dioxide features into MDI, for the available 48 defibrillations, boosted ROC-AUC to 93.8% and accuracy to 83.3% at 80% sensitivity. Conclusion
At clinically relevant sensitivity thresholds, the MDI provides improved performance as compared to AMSA, yielding fewer unsuccessful defibrillations. Addition of partial end-tidal carbon dioxide (PetCO2) signal improves accuracy and sensitivity of the MDI prediction model
Microstructural characterization of AISI 431 martensitic stainless steel laser-deposited coatings
High cooling rates during laser cladding of stainless steels may alter the microstructure and phase constitution of the claddings and consequently change their functional properties. In this research, solidification structures and solid state phase transformation products in single and multi layer AISI 431 martensitic stainless steel coatings deposited by laser cladding at different processing speeds are investigated by optical microscopy, Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), orientation imaging microscopy (OIM), ternary phase diagram, Schaeffler and TTT diagrams. The results of this study show how partitionless solidification and higher solidification rates alter the microstructure and phase constitution of martensitic stainless steel laser deposited coatings. In addition, it is shown that while different cladding speeds have no effect on austenite–martensite orientation relationship in the coatings, increasing the cladding speed has resulted in a reduction of hardness in deposited coatings which is in contrast to the common idea about obtaining higher hardness values at higher cladding speeds.
Mobilizing Cause Supporters through Group-Based Interaction
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Collective action expresses group-based identities, formed by supporters seeking to further particular social causes. While the development of groups linked to action necessitates interaction among supporters, little research has examined how these groups form. Utilizing responses of supporters who participated in 1 of 29 action-planning sessions, this research presents an initial attempt to identify the ingredients important to this process. It shows that to the extent that the actions agreed on in the course of group interactions were seen as capable of making a difference (action efficacy), and worthy of public expression (action voice), supporters’ group-based identification was enhanced. This in turn increased their willingness to engage in collective action. Practical implications and avenues for future research to understand the mobilization process are discussed.Australian Research Counci
On the role of confinement on solidification in pure materials and binary alloys
We use a phase-field model to study the effect of confinement on dendritic
growth, in a pure material solidifying in an undercooled melt, and in the
directional solidification of a dilute binary alloy. Specifically, we observe
the effect of varying the vertical domain extent () on tip selection,
by quantifying the dendrite tip velocity and curvature as a function of
, and other process parameters. As decreases, we find that the
operating state of the dendrite tips becomes significantly affected by the
presence of finite boundaries. For particular boundary conditions, we observe a
switching of the growth state from 3-D to 2-D at very small , in both
the pure material and alloy. We demonstrate that results from the alloy model
compare favorably with those from an experimental study investigating this
effect.Comment: 13 pages, 9 figures, 3 table
Power balance and scaling of the radiated power in the divertor and main plasma of Alcator C-Mod
Maximum illumination control system for photovoltaic panels orientation
The article describes the solar tracker for photovoltaic panels and energy systems based on such devices. The authors introduce the results of calculations of the solar tracker application effectiveness for solar energy systems and the results of the field testing in Tomsk
Inelastic interaction mean free path of negative pions in tungsten
The inelastic interaction mean free paths lambda of 5, 10, and 15 GeV/c pions were measured by determining the distribution of first interaction locations in a modular tungsten-scintillator ionization spectrometer. In addition to commonly used interaction signatures of a few (2-5) particles in two or three consecutive modules, a chi2 distribution is used to calculate the probability that the first interaction occurred at a specific depth in the spectrometer. This latter technique seems to be more reliable than use of the simpler criteria. No significant dependence of lambda on energy was observed. In tungsten, lambda for pions is 206 plus or minus 6 g/sq cm
Finitely generated free Heyting algebras via Birkhoff duality and coalgebra
Algebras axiomatized entirely by rank 1 axioms are algebras for a functor and
thus the free algebras can be obtained by a direct limit process. Dually, the
final coalgebras can be obtained by an inverse limit process. In order to
explore the limits of this method we look at Heyting algebras which have mixed
rank 0-1 axiomatizations. We will see that Heyting algebras are special in that
they are almost rank 1 axiomatized and can be handled by a slight variant of
the rank 1 coalgebraic methods
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