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Abstract Aim Trauma is a major cause of mortality leading to over 16,000 deaths annually in England and Wales alone. Code red traumas are the most extreme of these and a proportion will require immediate operative intervention. The aim of this study was to review the outcomes of patients presenting to a regional major trauma centre as code red traumas requiring immediate transfer to theatre and to identify a pathway to facilitate this process. Method Data were reviewed for all Code Red Traumas requiring immediate operative intervention between April 2017 and April 2021. Electronic records were searched to identify aetiologies, transfer times and post-operative morbidities and mortalities. Datasets were collected and analysed using Microsoft Excel software. Results 57 patients were identified and included. The average age was 39 years old. CT was performed in 52/59 patients (88.1%) and median time to CT was 32 minutes. All patients proceeded to theatre with an overall median time to theatre of 144.5 minutes. In hospital mortality was 19.3% (n = 11). Primary operating speciality varied with general surgery making up the majority with 30 cases. A consultant surgeon was present in 72% of cases and a consultant anaesthetist in 81% of cases. 84% (n = 48) of patients were admitted to ICU post-operatively. Conclusions Major trauma remains a significant cause of mortality in our cohort. We have developed a pathway for those requiring direct access to theatre. It is envisaged that this will facilitate expediated transfer to theatre and lead to improved patient outcomes.
Abstract : A general procedure for analysis of the response of concrete gravity dams, including the dynamic effects of impounded water and flexible foundation rock, to the transverse (horizontal) and vertical components of earthquake ground motion is presented. The problem is reduced to one in two dimensions, considering the transverse vibration of a monolith of the dam. The system is analyzed under the assumption of linear behavior for the concrete, foundation rock and water. The complete system is considered as composed of three substructures -- the dam, represented as a finite element system, the fluid domain, as a continuum of infinite length in the upstream direction, and the foundation rock region as a viscoelastic halfplane. The structural displacements of the dam are expressed as a linear combination of Ritz vectors, chosen as normal modes of an associated undamped dam-foundation system. The effectiveness of this analytical formulation lies in its being able to produce excellent results by considering only a few Ritz vectors. The modal displacements due to earthquake motion are computed by synthesizing their complex frequency responses using Fast Fourier Transform procedures. The stress responses are calculated from the modal displacements. An example analysis is presented to illustrate results obtained from this analytical procedure. Computation times for several analyses are presented to illustrate effectiveness of the procedure.
The rate of spin-surface crossing from the singlet to the triplet potential energy surface during methanol oxidation has been examined for classically spin-forbidden crossings. The Landau−Zener equation has been used to calculate the thermally-averaged spin transition probabilities for the nonadiabatic surface crossing reaction. Two active sites have been investigated: isolated vanadate species supported on silica (VOx/SiO2) and titania (VOx/TiO2). The results show that the rate of spin-surface crossing is much faster than the rate-limiting H-abstraction step on both active sites and is therefore not kinetically relevant.
In recent years, with the advent of femtosecond pulse technology, two-photon absorption has commenced to be used for exposing photo-resists. It is natural to ask then, what is the spatial resolution of two-photon lithography? There has already been some discussion of resolution limits in two-photon, scanning confocal fluorescence microscopy. We will find that ordinary two-photon exposure of photo-resist merely enhances the photographic contrast, or gamma. While this improves the spatial resolution somewhat, it does so at the expense of a requirement for tighter control over the incident light intensity. Instead, we introduce a new type of exposure system employing a multiplicity of 2-photon excitation frequencies which interfere with one another to produce a super-resolution stationary image, exhibiting a true doubling of the spatial resolution.
The oxidative dehydrogenation of alkanes (C2H6, C3H8, i-C4H10, and n-C4H10) was investigated on VOx supported on Al2O3. Rate constants for alkane dehydrogenation (k1), alkane combustion (k2), and alkene combustion (k3) were measured, and a model was developed to describe the effects of alkane composition on these rate constants. The proposed model accounts for the effects of the number of C−H bonds available for activation and the relative strengths of these bonds in both the reactant and the product molecules. The Brønsted−Evans−Polanyi (BEP) relationship is used to relate activation energies of secondary and tertiary C−H bonds to that of primary C−H bonds. The model gives a reasonable approximation of the relative order of alkane reactivity, expressed by k1 + k2, and the relative ranking of alkanes with respct to combustion versus oxidative dehydrogenation, expressed by k2/k1. The ratio of k2/k1 is described by the product of two components: one that depends on the nature, number, and relative strength of C−H bonds of surface alkoxides, and a second one that is independent of the alkoxide composition and structure but depends on the difference in the entropy of activation for COx precursor versus alkene formation. The model also explains the observed variation of k3 with alkene composition by considering two precursor states for alkenes. One is strongly bound through π-orbital interactions with Lewis acid centers, and the second weakly binds via H bonding and van der Waals interactions, similar to the binding of alkanes. As a result, the rate of alkene combustion depends strongly on the large heats of adsorption of alkenes and only slightly on the presence of weak allylic C−H bonds. The high rate of C2H4 combustion is thus a consequence of its high heat of adsorption.
Binary catalysts for oxydehydrogenation of ethane were prepared and tested: Mo[sub 19]NbO[sub x], Mo[sub 4]VO[sub x], V[sub 5]NbO[sub x]. The combination of Mo and V is more active, selective than V-Nb or Mo and Nb. Nb in catalysts, particularly ternary, inhibits CO[sub 2] formation. Propane oxydehydrogenation occurs at lower temperature than ethane conversion over both binary and ternary catalysts; however selectivity to propylene is lower than for ethylene from ethane. Propylene is completely converted to carbon oxides when charged to the catalyst in absence of propane. Attempts failed to obtain higher hydrocarbons by oligemerizing propylene over acidic catalysts as it is formed.
article Free Access Share on Observations on the dynamics of a congestion control algorithm: the effects of two-way traffic Authors: Lixia Zhang Computer Science Laboratory, Xerox Palo Alto Research Center Computer Science Laboratory, Xerox Palo Alto Research CenterView Profile , Scott Shenker Computer Science Laboratory, Xerox Palo Alto Research Center Computer Science Laboratory, Xerox Palo Alto Research CenterView Profile , Daivd D. Clark Laboratory for Computer Science, Massachusetts Institute of Technology Laboratory for Computer Science, Massachusetts Institute of TechnologyView Profile Authors Info & Claims ACM SIGCOMM Computer Communication ReviewVolume 21Issue 4Sept. 1991 pp 133–147https://doi.org/10.1145/115994.116006Online:01 August 1991Publication History 280citation1,639DownloadsMetricsTotal Citations280Total Downloads1,639Last 12 Months98Last 6 weeks15 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF
Abstract Many migratory species, from monarch butterflies to wildebeest, express partial migration, where only a subset of a population migrates. This intraspecific variation is likely to have large ecological consequences. We studied the ecological consequences of partial migration in a salmonid fish, Oncorhynchus mykiss , in coastal streams in California, USA. One ecotype, steelhead trout, migrates to the ocean, whereas the other, rainbow trout, completes its lifecycle in freshwater. Migration has a strong genetic basis in O. mykiss . In one stream, we found differences in the frequency of migration‐linked genotypes below and above a waterfall barrier (migratory allele frequency of 60% below vs. 31% above). Below the waterfall, in the migratory‐dominated region, the density of young fish (<1 yr old) was approximately twice that in the resident‐dominated region above the waterfall (0.46 vs. 0.26 individuals/m 2 , respectively), presumably reflecting the higher fecundity of migratory females. Additionally, there were half as many older fish (>1 yr old) in pools downstream of the waterfall (0.05 vs. 0.13 individuals/m 2 ). In a second stream, between‐year variation in the dominance of migratory vs. resident fish allowed us to explore differences in fish density and size structure through time, and we found a consistent pattern. In brief, when migratory genotypes dominated, we found higher densities of young fish and lower densities of older fish, resulting in a simpler size structure, compared to when resident genotypes dominated. Moreover, large resident trout had a slightly higher trophic position than young fish (3.92 vs. 3.42 in one creek and 3.77 vs. 3.17 in the other), quantified with stable isotope data. The difference in fish size structure did not generate trophic cascades. Partial migration is widespread among migratory populations, as is phenotypic divergence between resident and migratory forms, suggesting the potential for widespread ecological effects arising from this common form of intraspecific variation.
