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
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
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Variable responses of human and non-human primate gut microbiomes to a Western diet
BACKGROUND: The human gut microbiota interacts closely with human diet and physiology. To better understand the mechanisms behind this relationship, gut microbiome research relies on complementing human studies with manipulations of animal models, including non-human primates. However, due to unique aspects of human diet and physiology, it is likely that host-gut microbe interactions operate differently in humans and non-human primates. RESULTS: Here, we show that the human microbiome reacts differently to a high-protein, high-fat Western diet than that of a model primate, the African green monkey, or vervet (Chlorocebus aethiops sabaeus). Specifically, humans exhibit increased relative abundance of Firmicutes and reduced relative abundance of Prevotella on a Western diet while vervets show the opposite pattern. Predictive metagenomics demonstrate an increased relative abundance of genes associated with carbohydrate metabolism in the microbiome of only humans consuming a Western diet. CONCLUSIONS: These results suggest that the human gut microbiota has unique properties that are a result of changes in human diet and physiology across evolution or that may have contributed to the evolution of human physiology. Therefore, the role of animal models for understanding the relationship between the human gut microbiota and host metabolism must be re-focused.P40 OD010965 - NIH HHS; P40 RR019963 - NCRR NIH HHS; P51 OD011132 - NIH HHS; R01 RR016300 - NCRR NIH HHS; 5R01RR016300 - NCRR NIH HH
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Hippocampal CA1 gamma power predicts the precision of spatial memory judgments.
The hippocampus plays a critical role in spatial memory. However, the exact neural mechanisms underlying high-fidelity spatial memory representations are unknown. We report findings from presurgical epilepsy patients with bilateral hippocampal depth electrodes performing an object-location memory task that provided a broad range of spatial memory precision. During encoding, patients were shown a series of objects along the circumference of an invisible circle. At test, the same objects were shown at the top of the circle (0°), and patients used a dial to move the object to its location shown during encoding. Angular error between the correct location and the indicated location was recorded as a continuous measure of performance. By registering pre- and postimplantation MRI scans, we were able to localize the electrodes to specific hippocampal subfields. We found a correlation between increased gamma power, thought to reflect local excitatory activity, and the precision of spatial memory retrieval in hippocampal CA1 electrodes. Additionally, we found a similar relationship between gamma power and memory precision in the dorsolateral prefrontal cortex and a directional relationship between activity in this region and in the CA1, suggesting that the dorsolateral prefrontal cortex is involved in postretrieval processing. These results indicate that local processing in hippocampal CA1 and dorsolateral prefrontal cortex supports high-fidelity spatial memory representations
Harmful Algal Blooms: A Case Study in Two Mesotrophic Drinking Water Supply Reservoirs in South Carolina
2010 S.C. Water Resources Conferences - Science and Policy Challenges for a Sustainable Futur
Platinum bis(phosphine) complexes of 1,8-naphthosultam
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
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
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
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
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Highly selective and solvent-dependent reduction of Nitrobenzene to N-phenylhydroxylamine, azoxybenzene, and aniline catalyzed by phosphino-modified polymer immobilized ionic liquid-stabilized AuNPs
Gold nanoparticles stabilized by phosphine-decorated polymer immobilized ionic liquids (AuNP@PPh2-PIILP) is an extremely efficient multiproduct selective catalyst for the sodium borohydride-mediated reduction of nitrobenzene giving N-phenylhydroxylamine, azoxybenzene, or aniline as the sole product under mild conditions and a very low catalyst loading. The use of a single nanoparticle-based catalyst for the partial and complete reduction of nitroarenes to afford three different products with exceptionally high selectivities is unprecedented. Under optimum conditions, thermodynamically unfavorable N-phenylhydroxylamine can be obtained as the sole product in near quantitative yield in water, whereas a change in reaction solvent to ethanol results in a dramatic switch in selectivity to afford azoxybenzene. The key to obtaining such a high selectivity for N-phenylhydroxylamine is the use of a nitrogen atmosphere at room temperature as reactions conducted under an inert atmosphere occur via the direct pathway and are essentially irreversible, while reactions in air afford significant amounts of azoxy-based products by virtue of competing condensation due to reversible formation of N-phenylhydroxylamine. Ultimately, aniline can also be obtained quantitatively and selectively by adjusting the reaction temperature and time accordingly. Introduction of PEG onto the polyionic liquid resulted in a dramatic improvement in catalyst efficiency such that N-phenylhydroxylamine could be obtained with a turnover number (TON) of 100 000 (turnover frequency (TOF) of 73 000 h–1, with >99% selectivity), azoxybenzene with a TON of 55 000 (TOF of 37 000 h–1 with 100% selectivity), and aniline with a TON of 500 000 (TOF of 62 500 h–1, with 100% selectivity). As the combination of ionic liquid and phosphine is required to achieve high activity and selectivity, further studies are currently underway to explore whether interfacial electronic effects influence adsorption and thereby selectivity and whether channeling of the substrate by the electrostatic potential around the AuNPs is responsible for the high activity. This is the first report of a AuNP-based system that can selectively reduce nitroarenes to either of two synthetically important intermediates as well as aniline and, in this regard, is an exciting discovery that will form the basis to develop a continuous flow process enabling facile scale-up
Intranasal H5N1 vaccines, adjuvanted with chitosan derivatives, protect ferrets against highly pathogenic influenza intranasal and intratracheal challenge
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
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