Competition and coexistence of bond and charge orders in (TMTTF)2AsF6

(TMTTF)2AsF6 undergoes two phase transitions upon cooling from 300 K. At Tco=103 K a charge-ordering (CO) occurs, and at Tsp(B=9 T)=11 K the material undergoes a spin-Peierls (SP) transition. Within the intermediate, CO phase, the charge disproportionation ratio is found to be at least 3:1 from carbon-13 NMR 1/T1 measurements on spin-labeled samples. Above Tsp, up to about 3Tsp, 1/T1 is independent of temperature, indicative of low-dimensional magnetic correlations. With the application of about 0.15 GPa pressure, Tsp increases substantially, while Tco is rapidly suppressed, demonstrating that the two orders are competing. The experiments are compared to results obtained from calculations on the 1D extended Peierls-Hubbard model.Comment: 4 pages, 5 figure

Empirical validation of the InVEST water yield ecosystem service model at a national scale

A variety of tools have emerged with the goal of mapping the current delivery of ecosystem services and quantifying the impact of environmental changes. An important and often overlooked question is how accurate the outputs of these models are in relation to empirical observations. In this paper we validate a hydrological ecosystem service model (InVEST Water Yield Model) using widely available data. We modelled annual water yield in 22 UK catchments with widely varying land cover, population and geology, and compared model outputs with gauged river flow data from the UK National River Flow Archive. Values for input parameters were selected from existing literature to reflect conditions in the UK and were subjected to sensitivity analyses. We also compared model performance between precipitation and potential evapotranspiration data sourced from global- and UK-scale datasets. We then tested the transferability of the results within the UK by additional validation in a further 20 catchments. Whilst the model performed only moderately with global-scale data (linear regression of modelled total water yield against empirical data; slope = 0.763, intercept = 54.45, R2 = 0.963) with wide variation in performance between catchments, the model performed much better when using UK-scale input data, with closer fit to the observed data (slope = 1.07, intercept = 3.07, R2 = 0.990). With UK data the majority of catchments showed less than 10% difference between measured and modelled water yield but there was a minor but consistent overestimate per hectare (86 m3/ha/year). Additional validation on a further 20 UK catchments was similarly robust, indicating that these results are transferable within the UK. These results suggest that relatively simple models can give accurate measures of ecosystem services. However, the choice of input data is critical and there is a need for further validation in other parts of the worl

Development of clinical guidelines for the prescription of orthoses in patients with neurological disorders in The Netherlands

The objective of this study was to develop guidelines for the prescription of ankle-foot, knee, wrist-hand and elbow orthoses for patients with neurological disorders. The study is part of a more comprehensive study focusing on the development of clinical guidelines for the prescription of these orthoses in a wider patient population. Evidence from literature (reviews, randomized controlled trials with good quality), information from literature with a lower degree of evidence and information from structured interviews with experts in the field of orthotics, form the basis of statements presented in a Delphi procedure. The Delphi technique was used to gain consensus on statements published on the Internet. A group of experts in the field of orthotics and neurological disorders was asked to give their opinion on 41 statements. Statements with a general agreement of at least 75% were accepted. Statements with less general agreement were rewritten and the experts could react in a second and possibly in a third round. Afterwards, an opinion-based workshop was organized in which participants could react on preliminary guidelines and on Delphi-statements with between 65% and 75% agreement. Consensus on 32 statements was gained during the three rounds and the opinion-based workshop. These statements form the basis of the consensus based clinical guidelines for the prescription of orthoses in patients with neurological disorders

Early post-operative mortality after major lower limb amputation: A systematic review of population and regional based studies

Full-text is free to read on the publisher's website OBJECTIVE: Lower limb amputation is often associated with a high risk of early post-operative mortality. Mortality rates are also increasingly being put forward as a possible benchmark for surgical performance. The primary aim of this systematic review is to investigate early post-operative mortality following a major lower limb amputation in population/regional based studies, and reported factors that might influence these mortality outcomes. METHODS: Embase, PubMed, Cinahl and Psycinfo were searched for publications in any language on 30 day or in hospital mortality after major lower limb amputation in population/regional based studies. PRISMA guidelines were followed. A self developed checklist was used to assess quality and susceptibility to bias. Summary data were extracted for the percentage of the population who died; pooling of quantitative results was not possible because of methodological differences between studies. RESULTS: Of the 9,082 publications identified, results were included from 21. The percentage of the population undergoing amputation who died within 30 days ranged from 7% to 22%, the in hospital equivalent was 4-20%. Transfemoral amputation and older age were found to have a higher proportion of early post-operative mortality, compared with transtibial and younger age, respectively. Other patient factors or surgical treatment choices related to increased early post-operative mortality varied between studies. CONCLUSIONS: Early post-operative mortality rates vary from 4% to 22%. There are very limited data presented for patient related factors (age, comorbidities) that influence mortality. Even less is known about factors related to surgical treatment choices, being limited to amputation level. More information is needed to allow comparison across studies or for any benchmarking of acceptable mortality rates. Agreement is needed on key factors to be reported

Elbow orthoses:a review of literature

The objective of this study is to review the available literature on elbow orthoses in patients with various diagnoses to assess the scientific base of the prescription of elbow orthoses. A search of literature in Medline, Embase, Cochrane and Recal was performed using the keyword "elbow" combined with "orthosis related keywords". Abstracts were read to select the papers dealing primarily with monoarticular elbow orthoses. References of the selected papers were also examined. A total of 57 papers were read of which IS met the selection criteria, Both the quality and quantity of the studies appeared to be low, so in this study no definitive conclusions can be drawn about the efficacy of monoarticular elbow orthoses. Current prescriptions of elbow orthoses cannot be evidence based, because no scientific evidence on elbow orthoses is available