870 research outputs found

    Manipulation of drugs to achieve the required dose is intrinsic to paediatric practice but is not supported by guidelines or evidence

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    Background: A lack of age-appropriate formulations can make it difficult to administer medicines to children. A manipulation of the dosage form may be required to achieve the required dose. This study aimed to describe medicines that are manipulated to achieve the required dose in paediatric practice.Method: A structured, undisguised observational study and postal survey. The observational study investigated drug manipulations occurring in clinical practice across three sites. The questionnaire, administered to a sample of paediatric nurses throughout the UK, surveyed manipulations conducted and nurses' experiences and views.Results: The observational study identified 310 manipulations, of which 62% involved tablets, 21% were intravenous drugs and 10% were sachets. Of the 54 observed manipulations 40 involved tablets with 65% of the tablets being cut and 30% dispersed to obtain a smaller dose. 188 manipulations were reported by questionnaire respondents, of these 46% involved tablets, 12% were intravenous drugs, and 12% were nebuliser solutions. Manipulations were predominantly, but not exclusively, identified in specialist clinical areas with more highly dependent patients. Questionnaire respondents were concerned about the accuracy of the dose achieved following manipulations and the lack of practice guidance.Conclusion: Manipulations to achieve the required dose occur throughout paediatric in-patient settings. The impact of manipulations on the efficacy of the drugs, the accuracy of the dose and any adverse effects on patients is not known. There is a need to develop evidence-based guidance for manipulations of medicines in children

    Optical Properties of Iron Silicates in the Infrared to Millimeter as a Function of Temperatures and Wavelength

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    The Optical Properties of Astronomical Silicates with Infrared Techniques (OPASI-T) program utilizes multiple instruments to provide spectral data over a wide range of temperature and wavelengths. Experimental methods include Vector Network Analyzer (VNA) and Fourier Transform Spectroscopy (FTS) transmission, and reflection/scattering measurements. From this data, we can determine the optical parameters for the index of refraction, \textit{n}, and the absorption coefficient, \textit{k}. The analysis of the laboratory transmittance data for each sample type is based upon different mathematical models, which are applied to each data set according to their degree of coherence. Presented here are results from iron silicate dust grain analogs, in several sample preparations and at temperatures ranging from 5--300 K, across the infrared and millimeter portion of the spectrum (from 2.5--10,000 \mic\ or 4,000--1 \wvn).Comment: Revised manuscript submitted to Ap

    R-matrix Quantization of the Elliptic Ruijsenaars--Schneider model

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    It is shown that the classical L-operator algebra of the elliptic Ruijsenaars-Schneider model can be realized as a subalgebra of the algebra of functions on the cotangent bundle over the centrally extended current group in two dimensions. It is governed by two dynamical r and rˉ\bar{r}-matrices satisfying a closed system of equations. The corresponding quantum R and R‾\overline{R}-matrices are found as solutions to quantum analogs of these equations. We present the quantum L-operator algebra and show that the system of equations on R and R‾\overline{R} arises as the compatibility condition for this algebra. It turns out that the R-matrix is twist-equivalent to the Felder elliptic R^F-matrix with R‾\overline{R} playing the role of the twist. The simplest representation of the quantum L-operator algebra corresponding to the elliptic Ruijsenaars-Schneider model is obtained. The connection of the quantum L-operator algebra to the fundamental relation RLL=LLR with Belavin's elliptic R matrix is established. As a byproduct of our construction, we find a new N-parameter elliptic solution to the classical Yang-Baxter equation.Comment: latex, 29 pages, some misprints are corrected and the meromorphic version of the quantum L-operator algebra is discusse

    Lunar periodicity in the shell flux of some planktonic foraminifera in the Gulf of Mexico

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    Synchronised reproduction offers clear benefits to planktonic foraminifera – an important group of marine calcifiers – as it increases the chances of successful gamete fusion. Such synchrony requires tuning to an internal or external clock. Evidence exists for lunar reproductive cycles in some species, but its recognition in shell flux time series has proven difficult, raising questions about reproductive strategies. Using spectral analysis of a 6 year time series (mostly at weekly resolution) from the northern Gulf of Mexico we show that the shell flux of Globorotalia menardii, Globigerinella siphonifera, Orbulina universa, Globigerinoides sacculifer and in Globigerinoides ruber (both pink and white varieties) is characterised by lunar periodicity. The fluxes of Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globigerinella calida, Globorotalia crassaformis and Globigerinita glutinata do not show significant spectral power at the lunar frequency. If present, lunar periodicity is superimposed on longer term/seasonal changes in the shell fluxes, but accounts for a significant part of the variance in the fluxes. The amplitude of the lunar cycle increases roughly proportional with the magnitude of the flux, demonstrating that most of the population is indeed affected by lunar-phased synchronisation. Phasing of peak fluxes appears species-specific, with G. menardii, O. universa and G. sacculifer showing most peaks around the full moon and G. ruber one week later. Contrastingly, peaks G. siphonifera occur dominantly around new moon. Very limited literature exists on lunar phasing of foraminiferal export fluxes, but spatial differences in its presence may exist, corroborating the exogenous nature of lunar synchrony in planktonic foraminifera

    Ninth and Tenth Order Virial Coefficients for Hard Spheres in D Dimensions

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    We evaluate the virial coefficients B_k for k<=10 for hard spheres in dimensions D=2,...,8. Virial coefficients with k even are found to be negative when D>=5. This provides strong evidence that the leading singularity for the virial series lies away from the positive real axis when D>=5. Further analysis provides evidence that negative virial coefficients will be seen for some k>10 for D=4, and there is a distinct possibility that negative virial coefficients will also eventually occur for D=3.Comment: 33 pages, 12 figure

    Classes of fast and specific search mechanisms for proteins on DNA

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    Problems of search and recognition appear over different scales in biological systems. In this review we focus on the challenges posed by interactions between proteins, in particular transcription factors, and DNA and possible mechanisms which allow for a fast and selective target location. Initially we argue that DNA-binding proteins can be classified, broadly, into three distinct classes which we illustrate using experimental data. Each class calls for a different search process and we discuss the possible application of different search mechanisms proposed over the years to each class. The main thrust of this review is a new mechanism which is based on barrier discrimination. We introduce the model and analyze in detail its consequences. It is shown that this mechanism applies to all classes of transcription factors and can lead to a fast and specific search. Moreover, it is shown that the mechanism has interesting transient features which allow for stability at the target despite rapid binding and unbinding of the transcription factor from the target.Comment: 65 pages, 23 figure

    Commodifying development experience: deconstructing development as gift in the development blockbuster

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    This paper discusses the recent rise of popular ‘blockbuster’ books written by international development industry insiders and produced by commercial publishers. The paper explores a set of common stylistic devices found within this emerging genre. Though each book is different, a key trope is the story of an author's earlier professional life—the hard lessons and gritty insights that have supposedly emerged from it—that normally underpins each narrative. By living the challenges involved in development work at first hand, and by making mistakes and experiencing epiphanies along the way, these author-professionals want readers to know that they have found out the hard way that long-cherished beliefs about development now need to be questioned. Readers are invited to relive these lessons and epiphanies, and to think and act differently about development by upholding a highly pragmatic form of development professionalism. Combining elements of research monograph, self-help book and personal memoir, these development blockbuster books can be understood not only as commodities, but also as part of the development gift. The authors promise a gift of experience but, in reality, these books are mundane commodities enmeshed in capitalist exchange relations
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