Ultrasound by emergency physicians to detect abdominal aortic aneurysms: a UK case series

Early identification of abdominal aortic aneurysms in some patients can be difficult and the diagnosis is missed in up to 30% of patients. Ultrasound cannot be used to identify a leak, but the presence of an aneurysm in an unstable patient is conclusive. With minimal training emergency physicians can easily identify the aorta and thus in the early phase of resuscitation an aneurysm can be confidently excluded. The purpose of the examination is not to delineate the extent of the aneurysm, but to identify those patients that will need emergency surgery. A series of patients presented to the department in an unstable condition with equivocal abdominal signs. An ultrasound scan in the resuscitation room by members of the emergency department revealed an aneurysm, which was enough to convince the vascular surgeons to take the patient straight to theatre with good results. In patients who are stable, computed tomography will continue to be used to evaluate the extent of the aneurysm and identify a leak

Island size distributions in submonolayer growth: successful prediction by mean field theory with coverage dependent capture numbers

We show that mean-field rate equations for submonolayer growth can successfully predict island size distributions in the pre-coalescence regime if the full dependence of capture numbers on both the island size and the coverage is taken into account. This is demonstrated by extensive Kinetic Monte Carlo simulations for a growth kinetics with hit and stick aggregation. A detailed analysis of the capture numbers reveals a nonlinear dependence on the island size for small islands. This nonlinearity turns out to be crucial for the successful prediction of the island size distribution and renders an analytical treatment based on a continuum limit of the mean-field rate equations difficult.Comment: 4 pages, 4 figue

Problems with oral formulations prescribed to children: a focus group study of healthcare professionals

Background There is evidence to suggest that adherence with prescribed medication is lower amongst adolescents and children than in adults. Medication adherence rates between 11 and 93 % in paediatric patients have been reported. More research needs to be carried out in order to understand why medicines adherence is low and how adherence can be improved in children with long-term conditions. Personal communication with paediatricians in secondary care has highlighted that problems are most likely to be encountered by parents, carers, nurses and children themselves when administering medicines for prevalent long-term childhood conditions. Objective To explore problems with oral medicines prescribed to paediatric patients from the perspectives of medical practitioners, pharmacists and nurses. Setting Two NHS trusts in the West Midlands, UK. Methods Four focus groups (FG) were conducted. Five nurses, eight medical practitioners and six pharmacists participated in focus groups. The themes explored were problems experienced when prescribing, dispensing and administering oral medicines for children. Main outcome measure Themes evolving from Healthcare professionals reports on problems with administering medicines to paediatric patients. Results Two main themes: sensory and non-sensory emerged from the data. Included within these were taste, texture, colour, smell, size, swallowing, quantity, volume and manipulation with food. Taste was the most commonly reported barrier to medicines administration. Texture was reported to be a significant problem for the learning disability population. Medicines manipulation techniques were revealed across the groups, yet there was limited knowledge regarding the evidence base for such activity. Problems surrounding the supply of Specials medicines were discussed in-depth by the pharmacists. Conclusion Organoleptic and physical properties of medicines are key barriers to medicines administration. A robust scientific evidence-based approach is warranted to inform standardised protocols guiding healthcare professionals to support safe and effective medicines manipulation across all settings. Pharmacists’ knowledge of Specials medicines needs to be recognised as a valuable resource for doctors. Findings of this study should help to optimise paediatric prescribing and direct future formulation work

A Unified Treatment of Horizontal Direct Investment, Vertical Direct Investment, and the Pattern of Trade in Goods and Services

This paper contributes to research endogenizing multinational firms in general-equilibrium trade models. We attempt to integrate separate contributions on horizontal multinationals which produce the same final product in multiple locations, with work on vertical multinationals, which geographically fragment production by stages. Previously derived results now emerge as special cases of a more general model. Vertical multinationals dominate when countries are very different in relative factor endowments. Horizontal multinationals dominate when the countries are similar in size and in relative endowments, and trade costs are moderate to high. In some cases, foreign investment or trade liberalization leads to a reversal in the direction of trade. Investment liberalization can also lead to an increase in the volume of trade and produces a strong tendency toward factor-price equalization. Thus direct investment can be a complement to trade in both a volume-of-trade sense and in a welfare sense.

Evolution of unoccupied resonance during the synthesis of a silver dimer on Ag(111)

Silver dimers were fabricated on Ag(111) by single-atom manipulation using the tip of a cryogenic scanning tunnelling microscope. An unoccupied electronic resonance was observed to shift toward the Fermi level with decreasing atom-atom distance as monitored by spatially resolved scanning tunnelling spectroscopy. Density functional calculations were used to analyse the experimental observations and revealed that the coupling between the adsorbed atoms is predominantly direct rather than indirect via the Ag(111) substrate.Comment: 9 pages, 3 figure

Caesium on Si(100) Studied by Biassed Secondary Electron Microscopy

An ultra-high vacuum scanning electron microscope (UHV-SEM) has been used to study sub-monolayers of Cs on Si(100) surface. Cs adsorption on the surface causes a considerable change in the work function. Coverages below 1/2 monolayer (ML) have been estimated by correlating the work function changes with the secondary electron (SE) signal. It has been found that this signal is sensitive down to ~ 0.005 ML when the sample is biassed to a few hundred volts. Electron trajectories from a biassed sample have been simulated for electrons originating from different areas with different work functions across the sample. This indicates that variations in coverage can be determined by secondary electron imaging provided these coverages are less than 1/2 ML. The diffusion of Cs (\u3c 1/2 ML) above room temperature has been studied using the biassed-SE imaging technique. Observed diffusion profiles have unusual features including two linear regions. These can be explained by a model which contains two competing adsorption sites, and includes blocking of the diffusion paths by other Cs atoms

Capture numbers in the presence of repulsive adsorbate interactions

Capture numbers are used in models of nucleation and growth on surfaces, and have been widely applied to predict nucleation densities and other quantities via rate equations. In conventional nucleation theory, much effort has historically been expended on obtaining good expressions for capture numbers in the diffusion-limited case. However, recent experiments and calculations have shown that weak repulsive interactions between adsorbate atoms on relatively smooth (e.g., close-packed metal) surfaces may shift nucleation kinetics towards the attachment-limited case. This paper clarifies the distinctions between diffusion- and attachment-limited kinetics, and emphasizes the increased importance of the transient nucleation regime in the latter case, which is due to a combination of delayed nucleation and reduced capture. The consequences of long-range repulsive adsorbate interactions for the form and values of the capture numbers are explored, and the effects of attachment-limited kinetics in relation to low-temperature deposition and annealing experiments are demonstrated. An approximate interpolation scheme between attachment- and diffusion-limited kinetics is proposed, and tested against kinetic Monte Carlo simulations. Using this scheme to interpret recent scanning-tunneling microscopy results on Cu/Cu(111), lower and upper bounds on the maximum adatom-adatom potential repulsive energy of 10 and 14 meV are deduced

The effect of monomer evaporation on a simple model of submonolayer growth

We present a model for thin film growth by particle deposition that takes into account the possible evaporation of the particles deposited on the surface. Our model focuses on the formation of two-dimensional structures. We find that the presence of evaporation can dramatically affect the growth kinetics of the film, and can give rise to regimes characterized by different ``growth'' exponents and island size distributions. Our results are obtained by extensive computer simulations as well as through a simple scaling approach and the analysis of rate equations describing the system. We carefully discuss the relationship of our model with previous studies by Venables and Stoyanov of the same physical situation, and we show that our analysis is more general.Comment: 41 pages including figures, Revtex, to be published in Physical Review