A contemporary assessment of devices for Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA): resource-specific options per level of care

Purpose: Use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) as adjunct for temporary hemorrhage control in patients with exsanguinating torso hemorrhage is increasing. Characteristics of aortic occlusion balloons (AOB) are diverse and evolving as efforts are made to improve the technology. It is important to select a device that fits the requirements of the medical situation to minimize the risk of failure and complications. The aim of this study is to appraise guidance in the choice of an AOB in a specific situation. Methods: We assessed 29 AOB for differences and outline possible advantages and disadvantages of each. Bending stiffness was measured with a three-point bending device. Results: Diameter of the AOB ranged from 6 (ER-REBOA™) to 10 (Coda®-46) French. However, some need large-bore access sheaths up to 22 French (Fogarty®-45 and LeMaitre®-45) or even insertion via cut-down (Equalizer™-40). Bending stiffness varied from 0.08 N/mm (± 0.008 SD; Coda®-32) to 0.72 N/mm (± 0.024 SD; Russian prototype). Rescue Balloon™ showed kinking of the shaft at low bending pressures. The only non-compliant AOB is REBOA Balloon®. ER-REBOA™, Fogarty®, LeMaitre®, REBOA Balloon®, and Rescue Balloon™ are provided with external length marks to assist blind positioning. Conclusion: In resource-limited settings, a guidewire- and fluoroscopy-free, rather stiff device, such as ER-REBOA™, Fogarty®, and LeMaitre®, is warranted. Of these devices, ER-REBOA™ is the only catheter compatible with seven French sheaths and specifically designed for emergency hemorrhage control. Of the over-the-wire devices, Q50® has several features that facilitate use and reduce the risk of malplacement or vessel damage

Language in international business: a review and agenda for future research

A fast growing number of studies demonstrates that language diversity influences almost all management decisions in modern multinational corporations. Whereas no doubt remains about the practical importance of language, the empirical investigation and theoretical conceptualization of its complex and multifaceted effects still presents a substantial challenge. To summarize and evaluate the current state of the literature in a coherent picture informing future research, we systematically review 264 articles on language in international business. We scrutinize the geographic distributions of data, evaluate the field’s achievements to date in terms of theories and methodologies, and summarize core findings by individual, group, firm, and country levels of analysis. For each of these dimensions, we then put forward a future research agenda. We encourage scholars to transcend disciplinary boundaries and to draw on, integrate, and test a variety of theories from disciplines such as psychology, linguistics, and neuroscience to gain a more profound understanding of language in international business. We advocate more multi-level studies and cross-national research collaborations and suggest greater attention to potential new data sources and means of analysis

Methyl Halide Emissions from Savanna Fires in Southern Africa

The methyl halides, methyl chloride (CH3Cl), methyl bromide (CH3Br), and methyl iodide (CH3I), were measured in regional air samples and smoke from savanna fires in southern Africa during the Southern Africa Fire‐Atmosphere Research Initiative‐92 (SAFARI‐92) experiment (August–October 1992). All three species were significantly enhanced in the smoke plumes relative to the regional background. Good correlations were found between the methyl halides and carbon monoxide, suggesting that emission was predominantly associated with the smoldering phase of the fires. About 90% of the halogen content of the fuel burned was released to the atmosphere, mostly as halide species, but a significant fraction (3–38%) was emitted in methylated form. On the basis of comparison with the composition of the regional background atmosphere, emission ratios to carbon dioxide and carbon monoxide were determined for the methyl halide species. The emission ratios decreased in the sequence CH3Cl > CH3Br > CH3I. Extrapolation of these results in combination with data from other types of biomass burning, e.g. forest fires, suggests that vegetation fires make a significant contribution to the atmospheric budget of CH3Cl and CH3Br. For tropospheric CH3I, on the other hand, fires appear to be a minor source. Our results suggest that pyrogenic emissions of CH3Cl and CH3Br need to be considered as significant contributors to stratospheric ozone destruction

Increases in mercury emissions from desert soils in response to rainfall and irrigation

As part of an international Hg flux intercomparison at the Steamboat Springs, Nevada, geothermal area, several dynamic soil flux chambers and micrometeorological gradient systems were operated over desert soils in early September 1997. A series of unanticipated convective rain cells impacted the site with the first rainfall in ∼90 days, and the initial 4-cm rainfall increased soil moisture from ∼0.01 to 0.06% (vol/vol). Several chambers were operating prior to the events, and two were deployed over wet soils following rainfall. Rainfall resulted in an immediate and steep rise in ambient air Hg concentrations and soil Hg emissions which persisted for 12–24 hours. Fluxes increased most quickly and to a greater degree over the wettest soils, and the rate of increase was related to chamber design and flushing rate. The flux response was also apparent in the micrometeorological data. In general, soil emissions increased by an order of magnitude following the rain, and reached levels ∼6 times above those at the same time the previous day. These fluxes were significantly correlated with temperature, radiation, humidity, wind speed, and soil moisture. After drying for ∼40 hours, selected soil plots were manually irrigated with low-Hg-distilled water. Mercury emissions responded similarly across the three treated sites, uniformly increasing from ∼60 ng m⁻² h⁻¹ pretreatment to ∼650 ng m⁻² h⁻¹ posttreatment, which was a factor of ∼6 higher than adjacent control soils. Possible causes of the increases in flux include soil gas displacement, desorption of Hg° by water molecules, and desorption of Hg(II) and subsequent reduction in solution. The kinetics of the flux response, combined with local soil and climatic conditions, suggest that Hg emissions were responding primarily to soil moisture and solar radiation. These data have interesting implications for the role of changing regional climates on biogeochemical cycling of Hg.10 page(s

A postulated role for calcium oxalate in the regulation of calcium ions in the vicinity of stomatal guard cells.

Calcium ions are known to play an important part in signal transduction in stomatal guard cells. In Cummelina communis L., stomatal opening in isolated epidermis is strongly inhibited if the calcium concentration in the incubation medium is 0.1 mol mol m−3 or greater, It can be assumed that in the intact leaf, the apoplastic concentration of free calcium in the vicinity of the guard cells must be kept below this level if interference with stomatal functioning is to be avoided. When C. communis was grown with 15 mol m−3 calcium in the rhizosphere, the concentration of free calcium in the xylem sap in the shoot was found to be 3.76 mol m−3. A mechanism is clearly needed for reducing this concentration as the sap traverses the apoplast between the xylem and the stomatal guard cells. Evidence is presented here that the deposition of calcium oxalate in cells of the leaf achieves the necessary regulation. The protective role of the six specialized subsidiary cells in this species appears to be specially important. It is suggested that the regulation of apoplastic free calcium may take an important contribution to the effective stomatal control of gas exchange

The precambrian mafic magmatic record, including large igneous provinces of the kalahari craton and its constituents : A paleogeographic review

The study of Precambrian dyke swarms, sill provinces and large igneous provinces on the Kalahari craton in southern Africa has expanded greatly since the pioneering work initiated almost four decades ago. The main contributors to this progress have been a large number of precise U–Pb crystallization ages of mafic rocks, published in a number of recent papers. This information is compiled here into a series of maps that provide a nearly 3 billion year intraplate magmatic record of the Kalahari craton and its earlier constituents, the proto-Kalahari, Kaapvaal and Zimbabwe cratons. We also review their possible paleogeographic relations to other cratons or supercontinents. This review provides a more accessible overview of individual magmatic events, and mostly includes precise U–Pb ages of mafic dykes and sills, some of which can be linked to stratigraphically well-constrained volcanic rocks. The extrusion ages of these volcanic units are also starting to be refined by, among others, in situ dating of baddeleyite. Some mafic dyke swarms, previously characterized entirely on similarity in dyke trends within a swarm, are found to be temporally composite and sometimes consist of up to three different generations. Other mafic dyke swarms, with different trends, can now be linked to protracted volcanic events like the stratigraphically well preserved Mesoarchean Nsuze Group (Pongola Supergroup) and Neoarchean Ventersdorp Supergroup. Following upon these Archean events, shorter-lived Proterozoic large igneous provinces also intrude the Transvaal Supergroup, Olifantshoek Supergroup and Umkondo Group, and include the world’s largest layered intrusion, the Bushveld Complex. Longer-lived late Paleoproterozoic magmatic events are also preserved as mafic intrusions and lava units within the Waterberg and Soutpansberg groups as well as the granitic basement. Many gaps in our knowledge of the Precambrian mafic record of the Kalahari craton remain, but further multi-disciplinary studies combining the latest advances in U–Pb geochronology and both paleomagnetism and geochemistry will help solve the Precambrian paleogeographic puzzle