892 research outputs found

    Microwave-mediated synthesis of N-methyliminodiacetic acid (MIDA) boronates

    Get PDF
    A library of over 20, mainly aryl or heteroaryl, N-methyliminodiacetic acid (MIDA) boronates have been synthesised. A rapid microwave-mediated (MW) method (5–10 min) has been developed using polyethylene glycol 300 (PEG 300) as solvent. However, acetonitrile (MeCN) and dimethylformamide (DMF) were found to be alternative solvents, the latter especially for 2-substituted aryl boronic acids

    The evaluation of Education Maintenance Allowance Pilots: three years' evidence: a quantitative evaluation

    Get PDF
    This is the third report of the longitudinal quantitative evaluation of Education Maintenance Allowance (EMA) pilots and the first since the government announced that EMA is to be rolled out nationally from 2004. The evaluation was commissioned in 1999, by the Department for Education and Skills (DfES) from a consortium of research organisations, led by the Centre for Research in Social Policy (CRSP) and including the National Centre for Social Research, the Institute for Fiscal Studies (IFS) and the National Institute for Careers Education and Counselling (NICEC). The statistical evaluation design is a longitudinal cohort study involving large random sample surveys of young people (and their parents) in 10 EMA pilot areas and eleven control areas. Two cohorts of young people were selected from Child Benefit records. The first cohort of young people left compulsory schooling in the summer of 1999 and they, and their parents, were interviewed between October 1999 and April 2000 (Year 12 interview). A second interview was carried out with these young people between October 2000 and April 2001 (Year 13 interview). The second cohort left compulsory education the following summer of 2000 and young people, and their parents, were first interviewed between October 2000 and April 2001. The report uses both propensity score matching (PSM) and descriptive techniques, each of which brings their own particular strengths to the analysis

    The Advent Hope in the Middle Ages

    Get PDF
    Srednjovjekovni kršćani, premda zabrinuti zbog protjecanja vremena, s pouzdanjem su čekali Kristov drugi dolazak. Kako kaže cistercitski otac Guerric iz Ignyja: "Apsolutno sam siguran da će se on na kraju pojaviti i pokazati da me nije prevario; stoga ću ga, unatoč odgađanja što ga određuje, i dalje pouzdano čekati jer će on sigurno doći i neće zakasniti nijedan dan." (Guerric iz Ignyja, Liturgical Sermons I, Cistercian Fathers Series 8 /Shannon, 1971/, str. 3.) Žar što ga osjećamo u ovoj prvoj Guerricovoj propovijedi o dobu adventa iznenadit će neke čitatelje, jer su protestantski kršćani učeni da je adventna nada u srednjem vijeku nestala. No to je daleko od istine.Medieval Christians, although troubled by the passage of time, confi¬dently awaited the second advent of Christ. As the twelfth-century Cistercian father Guerric of Igny states, “I am absolutely sure that in the end he will appear and will prove not to have deceived me; so in spite of the delay he imposes I shall go on waiting for him confidently, because he certainly will come and will not be later than the most timely day.” The fervor of these words from Guerric’s first sermon for the advent season may surprise some readers, for typically, Protestant Christians have been taught that the advent hope was lost during the Middle Ages. Nothing could be further from the truth

    Modelling trends in OH radical concentrations using generalized additive models

    Get PDF
    During the TORCH campaign a zero dimensional box model based on the Master Chemical Mechanism was used to model concentrations of OH radicals. The model provided a close overall fit to measured concentrations but with some significant deviations. In this research, an approach was established for applying Generalized Additive Models (GAM) to atmospheric concentration data. Two GAM models were fitted to OH radical concentrations using TORCH data, the first using measured OH data and the second using MCM model results. GAM models with five smooth functions provided a close fit to the data with 78% of the deviance explained for measured OH and 83% for modelled OH. The GAM model for measured OH produced substantially better predictions of OH concentrations than the original MCM model results. The diurnal profile of OH concentration was reproduced and the predicted mean diurnal OH concentration was only 0.2% less than the measured concentration compared to 16.3% over-estimation by the MCM model. Photolysis reactions were identified as most important in explaining concentrations of OH. The GAM models combined both primary and secondary pollutants and also anthropogenic and biogenic species to explain changes in OH concentrations. Differences identified in the dependencies of modelled and measured OH concentrations, particularly for aromatic and biogenic species, may help to understand why the MCM model predictions sometimes disagree with measurements of atmospheric species

    The domestic and gendered context for retirement

    Get PDF
    Against a global backdrop of population and workforce ageing, successive UK governments have encouraged people to work longer and delay retirement. Debates focus mainly on factors affecting individuals’ decisions on when and how to retire. We argue that a fuller understanding of retirement can be achieved by recognizing the ways in which individuals’ expectations and behaviours reflect a complicated, dynamic set of interactions between domestic environments and gender roles, often established over a long time period, and more temporally proximate factors. Using a qualitative data set, we explore how the timing, nature and meaning of retirement and retirement planning are played out in specific domestic contexts. We conclude that future research and policies surrounding retirement need to: focus on the household, not the individual; consider retirement as an often messy and disrupted process and not a discrete event; and understand that retirement may mean very different things for women and for men

    Epidemiological associations between brachycephaly and upper respiratory tract disorders in dogs attending veterinary practices in England

    Get PDF
    Background: Brachycephalic dog breeds are increasingly common. Canine brachycephaly has been associated with upper respiratory tract (URT) disorders but reliable prevalence data remain lacking. Using primary-care veterinary clinical data, this study aimed to report the prevalence and breed-type risk factors for URT disorders in dogs. Results: The sampling frame included 170,812 dogs attending 96 primary-care veterinary clinics participating within the VetCompass Programme. Two hundred dogs were randomly selected from each of three extreme brachycephalic breed types (Bulldog, French Bulldog and Pug) and three common small-to medium sized breed types (moderate brachycephalic: Yorkshire Terrier and non-brachycephalic: Border Terrier and West Highland White Terrier). Information on all URT disorders recorded was extracted from individual patient records. Disorder prevalence was compared between groups using the chi-squared test or Fisher’s test, as appropriate. Risk factor analysis used multivariable logistic regression modelling. During the study, 83 (6.9 %) study dogs died. Extreme brachycephalic dogs (median longevity: 8.6 years, IQR: 2.4-10.8) were significantly younger at death than the moderate and non-brachycephalic group of dogs (median 12.7 years, IQR 11.1-15.0) (P \u3c 0.001). A higher proportion of deaths in extreme brachycephalic breed types were associated with URT disorders (4/24 deaths, 16.7 %) compared with the moderate and non-brachycephalic group (0/59 deaths, 0.0 %) (P = 0.001). The prevalence of having at least one URT disorder in the extreme brachycephalic group was higher (22.0 %, 95 % confidence interval (CI): 18.0-26.0) than in the moderate and non-brachycephalic group (9.7 %, 95 % CI: 7.1-12.3, P \u3c 0.001). The prevalence of URT disorders varied significantly by breed type: Bulldogs 19.5 %, French Bulldogs 20.0 %, Pugs 26.5 %, Border Terriers 9.0 %, West Highland White Terriers 7.0 % and Yorkshire Terriers 13.0 % (P \u3c 0.001). After accounting for the effects of age, bodyweight, sex, neutering and insurance, extreme brachycephalic dogs had 3.5 times (95 % CI: 2.4-5.0, P \u3c 0.001) the odds of at least one URT disorder compared with the moderate and non-brachycephalic group. Conclusions: In summary, this study reports that URT disorders are commonly diagnosed in Bulldog, French Bulldog, Pug, Border Terrier, WHWT and Yorkshire Terrier dogs attending primary-care veterinary practices in England. The three extreme brachycephalic breed types (Bulldog, French Bulldog and Pug) were relatively short-lived and predisposed to URT disorders compared with three other small-to-medium size breed types that are commonly owned (moderate brachycephalic Yorkshire Terrier and non-brachycephalic: Border Terrier and WHWT). Conclusions: In summary, this study reports that URT disorders are commonly diagnosed in Bulldog, French Bulldog, Pug, Border Terrier, WHWT and Yorkshire Terrier dogs attending primary-care veterinary practices in England. The three extreme brachycephalic breed types (Bulldog, French Bulldog and Pug) were relatively short-lived and predisposed to URT disorders compared with three other small-to-medium size breed types that are commonly owned (moderate brachycephalic Yorkshire Terrier and non-brachycephalic: Border Terrier and WHWT)

    Intercomparison of modal and sectional aerosol microphysics representations within the same 3-D global chemical transport model

    Get PDF
    In the most advanced aerosol-climate models it is common to represent the aerosol particle size distribution in terms of several log-normal modes. This approach, motivated by computational efficiency, makes assumptions about the shape of the particle distribution that may not always capture the properties of global aerosol. Here, a global modal aerosol microphysics module (GLOMAP-mode) is evaluated and improved by comparing against a sectional version (GLOMAP-bin) and observations in the same 3-D global offline chemistry transport model. With both schemes, the model captures the main features of the global particle size distribution, with sub-micron aerosol approximately unimodal in continental regions and bi-modal in marine regions. Initial bin-mode comparisons showed that the current values for two size distribution parameter settings in the modal scheme (mode widths and inter-modal separation sizes) resulted in clear biases compared to the sectional scheme. By adjusting these parameters in the modal scheme, much better agreement is achieved against the bin scheme and observations. Annual mean surface-level mass of sulphate, sea-salt, black carbon (BC) and organic carbon (OC) are within 25% in the two schemes in nearly all regions. Surface level concentrations of condensation nuclei (CN), cloud condensation nuclei (CCN), surface area density and condensation sink also compare within 25% in most regions. However, marine CCN concentrations between 30° N and 30° S are systematically 25–60% higher in the modal model, which we attribute to differences in size-resolved particle growth or cloud-processing. Larger differences also exist in regions or seasons dominated by biomass burning and in free-troposphere and high-latitude regions. Indeed, in the free-troposphere, GLOMAP-mode BC is a factor 2–4 higher than GLOMAP-bin, likely due to differences in size-resolved scavenging. Nevertheless, in most parts of the atmosphere, we conclude that bin-mode differences are much less than model-observation differences, although some processes are missing in these runs which may pose a bigger challenge to modal schemes (e.g., boundary layer nucleation and ultra-fine sea-spray). The findings here underline the need for a spectrum of complexity in global models, with size-resolved aerosol properties predicted by modal schemes needing to be continually benchmarked and improved against freely evolving sectional schemes and observations

    Organism-sediment interactions govern post-hypoxia recovery of ecosystem functioning

    Get PDF
    Hypoxia represents one of the major causes of biodiversity and ecosystem functioning loss for coastal waters. Since eutrophication-induced hypoxic events are becoming increasingly frequent and intense, understanding the response of ecosystems to hypoxia is of primary importance to understand and predict the stability of ecosystem functioning. Such ecological stability may greatly depend on the recovery patterns of communities and the return time of the system properties associated to these patterns. Here, we have examined how the reassembly of a benthic community contributed to the recovery of ecosystem functioning following experimentally-induced hypoxia in a tidal flat. We demonstrate that organism-sediment interactions that depend on organism size and relate to mobility traits and sediment reworking capacities are generally more important than recovering species richness to set the return time of the measured sediment processes and properties. Specifically, increasing macrofauna bioturbation potential during community reassembly significantly contributed to the recovery of sediment processes and properties such as denitrification, bedload sediment transport, primary production and deep pore water ammonium concentration. Such bioturbation potential was due to the replacement of the small-sized organisms that recolonised at early stages by large-sized bioturbating organisms, which had a disproportionately stronger influence on sediment. This study suggests that the complete recovery of organism-sediment interactions is a necessary condition for ecosystem functioning recovery, and that such process requires long periods after disturbance due to the slow growth of juveniles into adult stages involved in these interactions. Consequently, repeated episodes of disturbance at intervals smaller than the time needed for the system to fully recover organism-sediment interactions may greatly impair the resilience of ecosystem functioning.

    Characterization of Choroidal Layers in Normal Aging Eyes Using Enface Swept-Source Optical Coherence Tomography

    Get PDF
    Purpose To characterize qualitative and quantitative features of the choroid in normal eyes using enface swept-source optical coherence tomography (SS-OCT). Methods Fifty-two eyes of 26 consecutive normal subjects were prospectively recruited to obtain multiple three-dimensional 12x12mm volumetric scans using a long-wavelength high-speed SS-OCT prototype. A motion-correction algorithm merged multiple SS-OCT volumes to improve signal. Retinal pigment epithelium (RPE) was segmented as the reference and enface images were extracted at varying depths every 4.13 mu m intervals. Systematic analysis of the choroid at different depths was performed to qualitatively assess the morphology of the choroid and quantify the absolute thicknesses as well as the relative thicknesses of the choroidal vascular layers including the choroidal microvasculature (choriocapillaris, terminal arterioles and venules;CC) and choroidal vessels (CV) with respect to the subfoveal total choroidal thickness (TC). Subjects were divided into two age groups: younger (= 40 years). Results Mean age of subjects was 41.92 (24-66) years. Enface images at the level of the RPE, CC, CV, and choroidal-scleral interface were used to assess specific qualitative features. In the younger age group, the mean absolute thicknesses were: TC 379.4 mu m (SD +/- 75.7 mu m),CC 81.3 mu m (SD +/- 21.2 mu m) and CV 298.1 mu m (SD +/- 63.7 mu m). In the older group, the mean absolute thicknesses were: TC 305.0 mu m (SD +/- 50.9 mu m),CC 56.4 mu m (SD +/- 12.1 mu m) and CV 248.6 mu m (SD +/- 49.7 mu m). In the younger group, the relative thicknesses of the individual choroidal layers were: CC 21.5% (SD +/- 4.0%) and CV 78.4% (SD +/- 4.0%). In the older group, the relative thicknesses were: CC 18.9% (SD +/- 4.5%) and CV 81.1% (SD +/- 4.5%). The absolute thicknesses were smaller in the older age group for all choroidal layers (TC p=0.006, CC p=0.0003, CV p=0.03) while the relative thickness was smaller only for the CC (p=0.04). Conclusions Enface SS-OCT at 1050nm enables a precise qualitative and quantitative characterization of the individual choroidal layers in normal eyes. Only the CC is relatively thinner in the older eyes. In-vivo evaluation of the choroid at variable depths may be potentially valuable in understanding the natural history of age-related posterior segment disease
    corecore