Area limit laws for symmetry classes of staircase polygons

We derive area limit laws for the various symmetry classes of staircase polygons on the square lattice, in a uniform ensemble where, for fixed perimeter, each polygon occurs with the same probability. This complements a previous study by Leroux and Rassart, where explicit expressions for the area and perimeter generating functions of these classes have been derived.Comment: 18 pages, 3 figure

Strain bursts in plastically deforming Molybdenum micro- and nanopillars

Plastic deformation of micron and sub-micron scale specimens is characterized by intermittent sequences of large strain bursts (dislocation avalanches) which are separated by regions of near-elastic loading. In the present investigation we perform a statistical characterization of strain bursts observed in stress-controlled compressive deformation of monocrystalline Molybdenum micropillars. We characterize the bursts in terms of the associated elongation increments and peak deformation rates, and demonstrate that these quantities follow power-law distributions that do not depend on specimen orientation or stress rate. We also investigate the statistics of stress increments in between the bursts, which are found to be Weibull distributed and exhibit a characteristic size effect. We discuss our findings in view of observations of deformation bursts in other materials, such as face-centered cubic and hexagonal metals.Comment: 14 pages, 8 figures, submitted to Phil Ma

Homogeneous Gold Catalysis through Relativistic Effects: Addition of Water to Propyne

In the catalytic addition of water to propyne the Au(III) catalyst is not stable under non-relativistic conditions and dissociates into a Au(I) compound and Cl2. This implies that one link in the chain of events in the catalytic cycle is broken and relativity may well be seen as the reason why Au(III) compounds are effective catalysts.Comment: 12 pages, 3 figures, 1 tabl

Effect of alpha variation on the vibrational spectrum of Sr_2

We consider the effect of $\alpha$ variation on the vibrational spectrum of Sr$_2$ in the context of a planned experiment to test the stability of $\mu\equiv m_e/m_p$ using optically trapped Sr$_2$ molecules [Zelevinsky et al., Phys. Rev. Lett. {\bf 100}, 043201; Kotochigova et al., Phys. Rev. A {\bf 79}, 012504]. We find the prospective experiment to be 3 to 4 times less sensitive to fractional variation in $\alpha$ as it is to fractional variation in $\mu$. Depending on the precision ultimately achieved by the experiment, this result may give justification for the neglect of $\alpha$ variation or, alternatively, may call for its explicit consideration in the interpretation of experimental results.Comment: 5 pages, 3 figure

A prospective, blinded evaluation of a video-assisted ‘4-stage approach’ during undergraduate student practical skills training

BACKGROUND: The 4-stage approach (4-SA) is used as a didactic method for teaching practical skills in international courses on resuscitation and the structured care of trauma patients. The aim of this study was to evaluate objective and subjective learning success of a video-assisted 4-SA in teaching undergraduate medical students. METHODS: The participants were medical students learning the principles of the acute treatment of trauma patients in their multidiscipline course on emergency and intensive care medicine. The participants were quasi- randomly divided into two groups. The 4-SA was used in both groups. In the control group, all four steps were presented by an instructor. In the study group, the first two steps were presented as a video. At the end of the course a 5-minute objective, structured clinical examination (OSCE) of a simulated trauma patient was conducted. The test results were divided into objective results obtained through a checklist with 9 dichotomous items and the assessment of the global performance rated subjectively by the examiner on a Likert scale from 1 to 6. RESULTS: 313 students were recruited; the results of 256 were suitable for analysis. The OSCE results were excellent in both groups and did not differ significantly (control group: median 9, interquantil range (IQR) 8–9, study group: median 9, IQR 8–9; p = 0.29). The global performance was rated significantly better for the study group (median 1, IQR 1–2 vs. median 2, IQR 1–3; p < 0.01). The relative knowledge increase, stated by the students in their evaluation after the course, was greater in the study group (85% vs. 80%). CONCLUSION: It is possible to employ video assistance in the classical 4-SA with comparable objective test results in an OSCE. The global performance was significantly improved with use of video assistance

Cohesive energies of cubic III-V semiconductors

Cohesive energies for twelve cubic III-V semiconductors with zincblende structure have been determined using an ab-initio scheme. Correlation contributions, in particular, have been evaluated using the coupled-cluster approach with single and double excitations (CCSD). This was done by means of increments obtained for localized bond orbitals and for pairs and triples of such bonds. Combining these results with corresponding Hartree-Fock data, we recover about 92 \% of the experimental cohesive energies.Comment: 16 pages, 1 figure, late

The effects of trauma on intimate relationships: A qualitative study with clinical couples

Research has traditionally focused on the development of symptoms in those who experienced trauma directly but has overlooked the impact of trauma on victims' families. In recent years, researchers and clinicians have begun to examine how individual exposure to traumatic events affects the spouses or partners, children, and professional helpers of trauma survivors. The current study examines qualitative interview data from 17 individuals, analyzed using a retroductive methodology to identify how intimate relationships are affected when there is a history of trauma exposure. The following primary themes were identified: increased communication, decreased communication, increased cohesion/connection, decreased cohesion/connection, increased understanding, decreased understanding, sexual intimacy problems, symptoms of relationship distress, support from partner, and relationship resources. Areas for future research and clinical implications are identified

Quantum Computer with Mixed States and Four-Valued Logic

In this paper we discuss a model of quantum computer in which a state is an operator of density matrix and gates are general quantum operations, not necessarily unitary. A mixed state (operator of density matrix) of n two-level quantum systems is considered as an element of 4^n-dimensional operator Hilbert space (Liouville space). It allows to use a quantum computer model with four-valued logic. The gates of this model are general superoperators which act on n-ququat state. Ququat is a quantum state in a four-dimensional (operator) Hilbert space. Unitary two-valued logic gates and quantum operations for an n-qubit open system are considered as four-valued logic gates acting on n-ququat. We discuss properties of quantum four-valued logic gates. In the paper we study universality for quantum four-valued logic gates.Comment: 17 page

Use of the GlideScope®-Ranger for pre-hospital intubations by anaesthesia trained emergency physicians – an observational study

Background: Pre-hospital endotracheal intubation is more difficult than in the operating room (OR). Therefore, enhanced airway management devices such as video laryngoscopes may be helpful to improve the success rate of pre-hospital intubation. We describe the use of the Glidescope®-Ranger (GS-R) as an alternative airway tool used at the discretion of the emergency physician (EP) in charge. Methods: During a 3.5 year period, the GS-R was available to be used either as the primary or backup tool for pre-hospital intubation by anaesthesia trained EP with limited expertise using angulated videolaryngoscopes. Results: During this period 672 patients needed pre-hospital intubation of which the GS-R was used in 56 cases. The overall GS-R success rate was 66 % (range of 34–100 % among EP). The reasons for difficulties or failure included inexperience of the EP with the GS-R, impaired view due to secretion, vomitus, blood or the inability to see the screen in very bright environment due to sunlight. Conclusion: Special expertise and substantial training is needed to successfully accomplish tracheal intubation with the GS-R in the pre-hospital setting. Providers inexperienced with DL as well as video-assisted intubation should not expect to be able to perform tracheal intubation easily just because a videolaryngoscope is available. Additionally, indirect laryngoscopy might be difficult or even impossible to achieve in the pre-hospital setting due to impeding circumstances such as blood, secretions or bright sun-light. Therefore, videolaryngoscopes, here the GS-R, should not be considered as the “Holy Grail” of endotracheal intubation, neither for the experts nor for inexperienced providers. Electronic supplementary material The online version of this article (doi:10.1186/s12873-016-0069-2) contains supplementary material, which is available to authorized users