483 research outputs found

    Automatic Locally Stationary Time Series Forecasting with application to predicting U.K. Gross Value Added Time Series under sudden shocks caused by the COVID pandemic

    Get PDF
    Accurate forecasting of the U.K. gross value added (GVA) is fundamental for measuring the growth of the U.K. economy. A common nonstationarity in GVA data, such as the ABML series, is its increase in variance over time due to inflation. Transformed or inflation-adjusted series can still be challenging for classical stationarity-assuming forecasters. We adopt a different approach that works directly with the GVA series by advancing recent forecasting methods for locally stationary time series. Our approach results in more accurate and reliable forecasts, and continues to work well even when the ABML series becomes highly variable during the COVID pandemic.Comment: 21 pages, 4 figure

    Harmful Algal Blooms: A Case Study in Two Mesotrophic Drinking Water Supply Reservoirs in South Carolina

    Get PDF
    2010 S.C. Water Resources Conferences - Science and Policy Challenges for a Sustainable Futur

    Platinum bis(phosphine) complexes of 1,8-naphthosultam

    Get PDF
    The work in this project was supported by the Engineering and Physical Sciences Research Council (EPSRC).A series of bis(phosphine) platinum complexes 1-4 and 6-8 that bear the 1,8-naphthosultam ligand (L) have been synthesised. The nitrogen atom in L was deprotonated with sodium tert-butoxide to form the sodium salt. Metathetical reaction of the sodium salt (1 eq.) with the appropriate cis-dichlorobis(phosphine) platinum (1 eq.) in THF resulted in the formation of platinum complexes [Pt(PR3)2(L)Cl] (R3 = Ph3; 1, Ph2Me; 2, PhMe2; 3, Me3; 4), whilst reaction with [Pt(COD)Cl2] afforded [Pt(COD)(L)Cl] (5). The corresponding reaction employing two equivalents of L, two equivalents of NaOtBu and one equivalent of [Pt(PR3)2Cl2]/[Pt(COD)Cl2] yielded complexes [Pt(PR3)2(L)2] (R3 = Ph2Me; 6, PhMe2; 7, Me3; 8) and [Pt(COD)(L)2] (9). L, 1, 5 and 9 have been fully characterised, principally by multinuclear magnetic resonance and IR spectroscopy and mass spectrometry, the remaining members of the series were analysed by 31P NMR only. Unsymmetrical complexes 1-4 provide examples of AX spin systems, with appropriate satellites attributed to 31P NMR-195Pt coupling. X-ray structures determined for 1,8-naphthosultam L, and complexes 1, 5 and 9 and where appropriate the platinum metal geometry, N-S distance and ligand distortions were compared.PostprintPeer reviewe

    The Design and Validation of the Quantum Mechanics Conceptual Survey

    Full text link
    The Quantum Mechanics Conceptual Survey (QMCS) is a 12-question survey of students' conceptual understanding of quantum mechanics. It is intended to be used to measure the relative effectiveness of different instructional methods in modern physics courses. In this paper we describe the design and validation of the survey, a process that included observations of students, a review of previous literature and textbooks and syllabi, faculty and student interviews, and statistical analysis. We also discuss issues in the development of specific questions, which may be useful both for instructors who wish to use the QMCS in their classes and for researchers who wish to conduct further research of student understanding of quantum mechanics. The QMCS has been most thoroughly tested in, and is most appropriate for assessment of (as a posttest only), sophomore-level modern physics courses. We also describe testing with students in junior quantum courses and graduate quantum courses, from which we conclude that the QMCS may be appropriate for assessing junior quantum courses, but is not appropriate for assessing graduate courses. One surprising result of our faculty interviews is a lack of faculty consensus on what topics should be taught in modern physics, which has made designing a test that is valued by a majority of physics faculty more difficult than expected.Comment: Submitted to Physical Review Special Topics: Physics Education Researc

    E-cigarette use and willingness to smoke: a sample of adolescent non-smokers

    Get PDF
    ABSTRACT Objective There is little evidence on the consequences of using electronic cigarettes (e-cigarette) in adolescence. With a multiethnic sample of non-smokers, we assessed the relation between e-cigarette use and social-cognitive factors that predict smoking of combustible cigarettes. Methods School-based cross-sectional survey of 2309 high school students (mean age 14.7 years). Participants reported on e-cigarette use and cigarette use; on smoking-related cognitions (smoking expectancies, prototypes of smokers) and peer smoker affiliations; and on willingness to smoke cigarettes. Regression analyses conducted for non-cigarette smokers tested the association between e-cigarette use and willingness to smoke cigarettes, controlling for demographics, parenting, academic and social competence, and personality variables. Structural equation modelling (SEM) analysis tested whether the relation between e-cigarette use and willingness to smoke was mediated through any of the three smoking-related variables. Results Non-smokers who had used e-cigarettes (18% of the total sample) showed more willingness to smoke cigarettes compared with those who had never used any tobacco product; the adjusted OR was 2.35 (95% CI 1.73 to 3.19). SEM showed that the relation between e-cigarette use and willingness to smoke was partly mediated through more positive expectancies about smoking, but there was also a direct path from e-cigarette use to willingness. Conclusions Among adolescent non-smokers, e-cigarette use is associated with willingness to smoke, a predictor of future cigarette smoking. The results suggest that use of e-cigarettes by adolescents is not without attitudinal risk for cigarette smoking. These findings have implications for formulation of policy about access to e-cigarettes by adolescents. BACKGROUN

    The status of sow welfare in selected districts of Uganda

    Get PDF
    Objective The pig sector in Uganda is among the fastest growing livestock sectors and is characterized by low productivity from limited resources and veterinary support. As the welfare status of pigs in the system is unknown a cross-sectional welfare assessment was carried out in four districts in central Uganda (Masaka, Mukono, Mpigi and Wakiso) to identify issues requiring action. Materials and methods Data were collected from 270 pig farms. Data on animal-based indicators (body condition and physical injuries) and resource-based indicators (housing and water supply) were obtained from physical assessments of pigs and farm facilities. Management data (morbidity and mortality) and demographic details were collected from farmer interview. We present sow results as they are the highest value animal of the herd, both raising piglets and requiring resource investment. Results Across all farms, sow mortality was 2.5%. Animal-based indicators identified 9% of sows with diarrhea, 7.6% with lameness and 92% dry or lactating were found to be ‘skinny’ (body condition score≤2). All of these are indicative of underperforming sows that may be at risk of low litter indices and shorter productive lives. Sow behaviour was restricted in 19% of cases, and while 93% of sows had access to continuous water, only 48.8% received clean water, which creates a risk of disease spread. Of reported health issues, 20% farms reported sows experiencing stillbirths, 15% ill thrift, 12.5% respiratory issues and 10.8% gastrointestinal issues. Conclusion These welfare issues indicates that a proportion of sows were in pain, discomfort and potentially hungry, which in turn negatively impact on owner livelihoods from wasted resources and opportunities. Future interventions focusing on herd health should focus on diseases and poor nutrition. Interventions that provide access to clean water and optimum living space that give sows the ability to move more freely are also required

    Intranasal H5N1 vaccines, adjuvanted with chitosan derivatives, protect ferrets against highly pathogenic influenza intranasal and intratracheal challenge

    Get PDF
    We investigated the protective efficacy of two intranasal chitosan (CSN and TM-CSN) adjuvanted H5N1 Influenza vaccines against highly pathogenic avian Influenza (HPAI) intratracheal and intranasal challenge in a ferret model. Six groups of 6 ferrets were intranasally vaccinated twice, 21 days apart, with either placebo, antigen alone, CSN adjuvanted antigen, or TM-CSN adjuvanted antigen. Homologous and intra-subtypic antibody cross-reacting responses were assessed. Ferrets were inoculated intratracheally (all treatments) or intranasally (CSN adjuvanted and placebo treatments only) with clade 1 HPAI A/Vietnam/1194/2004 (H5N1) virus 28 days after the second vaccination and subsequently monitored for morbidity and mortality outcomes. Clinical signs were assessed and nasal as well as throat swabs were taken daily for virology. Samples of lung tissue, nasal turbinates, brain, and olfactory bulb were analysed for the presence of virus and examined for histolopathological findings. In contrast to animals vaccinated with antigen alone, the CSN and TM-CSN adjuvanted vaccines induced high levels of antibodies, protected ferrets from death, reduced viral replication and abrogated disease after intratracheal challenge, and in the case of CSN after intranasal challenge. In particular, the TM-CSN adjuvanted vaccine was highly effective at eliciting protective immunity from intratrache
    • …
    corecore