2,628 research outputs found
Quantifying the transboundary contribution of nitrogen oxides to UK air quality
Nitrogen dioxide (NO2) pollution is an important contributor to poor air quality (AQ) and a significant cause of premature deaths in the UK. Although transboundary (i.e., international) transport of pollution to the UK is believed to have an impact on UK pollutant concentrations, large uncertainties remain in these estimates. Therefore, the extent to which emission reductions in neighbouring countries would benefit UK AQ relative to local emission reductions also remains unknown. We have used a backâtrajectory model in conjunction with synoptic scale classifications of UK circulation patterns (Lamb Weather Types [LWT]), to quantify the accumulation of nitrogen oxide (NO x = NO2â+âNO) emissions in air masses enâroute to the UK. This novel method presents a computationally inexpensive and useful method of quantifying the accumulation of pollutants under different circulation patterns. We find the highest accumulated NO x totals occur under southâeasterly and southerly flows (>15âÎŒgâ
mâ2), with a substantial contribution from outwith the UK (>25%). In contrast, the total accumulated NO x under northerly and westerly flows is lower (âŒ10 ÎŒgâ
mâ2), and dominated by UK emissions (>95%). This indicates that European emissions can contribute substantially to UK localâscale pollution in urban areas under southâeasterly and southerly flows. The sensitivity of integrated NO x emission totals under different air masses is investigated by modelling future European emission contributions based on emission reduction targets. Under targets set by the European Union, there would be a decrease in accumulated NO x emissions in London under most wind directions except for northâwesterly, westerly and northerly flow. The largest benefits to UK AQ from transboundary contributions occur with emission reductions in the Benelux region, due to its close proximity and high NO x emission rates, emphasising the importance of international cooperation in improving local AQ
Cluster J Mycobacteriophages: Intron Splicing in Capsid and Tail Genes
Bacteriophages isolated on Mycobacterium smegmatis mc2155 represent many distinct genomes sharing little or no DNA sequence similarity. The genomes are architecturally mosaic and are replete with genes of unknown function. A new group of genomes sharing substantial nucleotide sequences constitute Cluster J. The six mycobacteriophages forming Cluster J are morphologically members of the Siphoviridae, but have unusually long genomes ranging from 106.3 to 117 kbp. Reconstruction of the capsid by cryo-electron microscopy of mycobacteriophage BAKA reveals an icosahedral structure with a triangulation number of 13. All six phages are temperate and homoimmune, and prophage establishment involves integration into a tRNA-Leu gene not previously identified as a mycobacterial attB site for phage integration. The Cluster J genomes provide two examples of intron splicing within the virion structural genes, one in a major capsid subunit gene, and one in a tail gene. These genomes also contain numerous free-standing HNH homing endonuclease, and comparative analysis reveals how these could contribute to genome mosaicism. The unusual Cluster J genomes provide new insights into phage genome architecture, gene function, capsid structure, gene mobility, intron splicing, and evolution. © 2013 Pope et al
Separation between coherent and turbulent fluctuations. What can we learn from the Empirical Mode Decomposition?
The performances of a new data processing technique, namely the Empirical
Mode Decomposition, are evaluated on a fully developed turbulent velocity
signal perturbed by a numerical forcing which mimics a long-period flapping.
First, we introduce a "resemblance" criterion to discriminate between the
polluted and the unpolluted modes extracted from the perturbed velocity signal
by means of the Empirical Mode Decomposition algorithm. A rejection procedure,
playing, somehow, the role of a high-pass filter, is then designed in order to
infer the original velocity signal from the perturbed one. The quality of this
recovering procedure is extensively evaluated in the case of a "mono-component"
perturbation (sine wave) by varying both the amplitude and the frequency of the
perturbation. An excellent agreement between the recovered and the reference
velocity signals is found, even though some discrepancies are observed when the
perturbation frequency overlaps the frequency range corresponding to the
energy-containing eddies as emphasized by both the energy spectrum and the
structure functions. Finally, our recovering procedure is successfully
performed on a time-dependent perturbation (linear chirp) covering a broad
range of frequencies.Comment: 23 pages, 13 figures, submitted to Experiments in Fluid
Triggers for acute flare in adults with, or at risk of, knee osteoarthritis: a web-based case-crossover study in community-dwelling adults.
OBJECTIVE: To identify proximate causes ('triggers') of flares in adults with, or at risk of, knee osteoarthritis (OA), estimate their course and consequences, and determine higher risk individuals. METHODS: In this 13-week web-based case-crossover study adults aged â„40 years, with or without a recorded diagnosis of knee OA, and no inflammatory arthropathy who self-reported a knee flare completed a questionnaire capturing information on exposure to 21 putative activity-related, psychosocial and environmental triggers (hazard period, â€72 hours prior). Comparisons were made with identical exposure measurements at four 4-weekly scheduled time points (non-flare control period) using conditional logistic regression. Flare was defined as a sudden onset of worsening signs and symptoms, sustained for â„24 hours. Flare characteristics, course and consequence were analysed descriptively. Associations between flare frequency and baseline characteristics were estimated using Poisson regression. RESULTS: Of 744 recruited participants (mean age (SD) 62.1 (10.2) years; 61% female), 376 reported 568 flares (hazards) and provided 867 valid control period measurements. Thirteen exposures (8 activity-related, 5 psychosocial/environmental) were positively associated with flare onset within 24 hours (strongest odds ratio estimate, knee buckling: 9.06: 95% confidence interval [CI] 5.86, 13.99; weakest, cold/damp weather: 1.45: 95%CI 1.12, 1.87). Median flare duration was 5 days (IQR 3, 8), less common if older (incident rate ratio [IRR] 0.98: 95%CI 0.97, 0.99), more common if female (IRR 1.85: 95%CI 1.43, 2.39). CONCLUSIONS: Multiple activity-related, psychosocial and environmental exposures are implicated in triggering flares. This evidence can help inform prevention and acute symptom management for patients and clinicians
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Delayed chilling appears to counteract flowering advances of apricot in southern UK
Temperatures are rising across the globe, and the UK is no
exception. Spring phenology of perennial fruit crops is to a large extent
determined by temperature during effective chilling (endo-dormancy) and
heat accumulation (eco-dormancy) periods. We used the apricot flowering
records of the UK National Fruit Collections (NFC) to determine the
influence of temperature trends over recent decades (1960 to 2014) on
apricot (Prunus armeniaca L.) flowering time. Using Partial Least Squares
(PLS) regression, we determined the respective periods for calculating
chill and heat accumulation. Results suggested intervals between
September 27th and February 26th and between December 31st and April 12th
as the effective chilling and warming periods, respectively. Flowering
time was correlated with temperature during both periods, with warming
during chilling corresponding to flowering delays by 4.82 d°C-1, while
warming during heat accumulation was associated with bloom advances by
9.85 d°C-1. Heat accumulation started after accumulating 62.7 ± 5.6 Chill
Portions, and flowering occurred after a further 3744 ± 1538 Growing
Degree Hours (above a base temperature of 4°C, with optimal growth at
26°C). When examining the time series, the increase in temperature during
the chilling period did not appear to decrease overall chill accumulation
during the chilling period but to delay the onset of chill accumulation
and the completion of the the average chill accumulation necessary to
start heat accumulation. The resulting delay in heat responsiveness
appeared to weaken the phenology-advancing effect of spring warming.
These processes may explain why apricot flowering time remained
relatively unchanged despite significant temperature increases. A
consequence of this may be a reduction of frost risk for early flowering
crops such as apricot in the UK
Acute Flares of Knee Osteoarthritis (the ACT-FLARE Study): Protocol for a Web-Based Case-Crossover Study in Community-Dwelling Adults.
BACKGROUND
The cardinal feature of osteoarthritis (OA) is pain. Although heterogeneity in pain and function have been demonstrated in the long-term course of OA, the more proximate determinants of acute flare-ups remain less clear. How short-term intermittent or transient exposures trigger acute flare-ups has important implications for effective and sustainable self-management strategies.
OBJECTIVE
The primary objective of this study is to identify potential triggers of acute flares in knee OA. Secondary objectives are to determine their course and consequences and describe high-risk participant profiles.
METHODS
We carried out a Web-based case-crossover study. This study aims to recruit 620 community-dwelling adults aged â„40 years, resident in England, and who have knee pain, with or without a recorded diagnosis of knee OA, and no preexisting diagnosis of inflammatory arthropathy. Participants will be recruited via 3 routes: (1) general practice registers, (2) offline community advertisement, and (3) online social media advertisement. By using questionnaires comparing periods before participants' self-reported flare-up episodes (hazard periods) with periods during the study when their knee OA symptoms are stable (control periods), triggers preceding flare-ups will be identified and examined using conditional logistic regression. Time-to-resolution of flare-up will be examined by monitoring people's daily pain, bothersomeness, and medication usage until the participant reports when their flare-up episode ends. Rates of flare-ups will be examined across different participant and flare characteristics using regression models to identify high-risk participant profiles. A study-specific Patient Advisory Group (PAG) is providing suggestion, input, and ongoing support for all stages of the research process.
RESULTS
Participant recruitment opened in July 2018 and is anticipated to continue for 6 months. The study results will be disseminated through a number of channels, including relevant national or international conferences and peer-reviewed publication in a medical journal, via advocacy or charity organizations, such as Versus Arthritis and across social media. Findings will be fed back to members of our PAG, study participants, and clinicians from participating primary care general practices. The PAG will also take an active role in the overall dissemination strategy.
CONCLUSIONS
This study will provide empirical evidence to help patients identify common knee OA flare triggers and provide health care professionals with questions to identify patients at most risk of frequent flare-ups. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/13428
007 Khaled Amrouni et.al,2015-Poster of Petrographic Methods: Integrated Quantitative and Qualitative Petrographic and Diagenetic Methods to define Carbonate Outcrop and Reservoir...
The petrographic and diagenetic lab work of the Cyrenaican Miocene carbonate rocks northeast Libya
involves an intensive study of 503 hand samples and their thin sections. 148 samples of the measured field section
A1 of 74m thick were selected at 0.5 m intervals and then prepared to be studied.
Proper thin sections preparation required insertion of some dyes and chemical treatments. Blue dye was
inserted into the epoxy of all thin sections to enhance porosity identification. Alizarin Red-S stain was used to
distinguish between calcite and dolomite minerals, and potassium ferricyanide stain was used to differentiate ferroan
from non-ferroan carbonate minerals.
For the petrographic work, a three part thin section description scheme was established and followed. It
includes: 1) quantitative analysis, 2) qualitative analysis, and 3) diagenetic process and their paragenetic sequence.
The quantitative part involved determining the type and percentage of grains/fossils, matrix, cement, and pores. The
qualitative studies rock textures (fabrics and grain size), sedimentary structures (primary and secondary), and trace
fossils. Diagenetic processes includes micritization, dissolution/leaching (pore creations), cementation (pore
destruction), compaction (mechanical and chemical), and neomorphism (recrystallization, inversion, and
replacement). Through the cross cutting relationship the paragenetic sequence were defined by putting each
diagenetic event in its proper relative time order of occurrence.
The most important final products of these integrated petrographic and diagenetic methods are curves that
define vital reservoir rocks characterizations such as high/low porosity zones and their types, high/low cement zones
and their types, grain dominated versus mud dominated zones, high/low diagenetically affected zones and type of
diagenesis, bio-zones, dolomite versus calcite zones, carbonate texture curves, dolomite types and zones, and a chart
of the paragenetic sequence of the diagenetic events and their processes. In addition, the depositional and diagenetic
reservoir properties are interpreted in the sedimentological and sequence stratigraphic context of the studied
Cyrenaican Miocene sequence to determine the extent at which the relative sea level changes and tectonics could
control the carbonate reservoir properties
Microcrystals coating the wing membranes of a living insect (Psocoptera: Psyllipsocidae) from a Brazilian cave
Two specimens of Psyllipsocus yucatan with black wings were found with normal individuals of this species on guano piles produced by the common vampire bat Desmodus rotundus. These specimens have both pairs of wings dorsally and ventrally covered by a black crystalline layer. They did not exhibit any signs of reduced vitality in the field and their morphology is completely normal. This ultrathin (1.5 ”m) crystalline layer, naturally deposited on a biological membrane, is documented by photographs, SEM micrographs, energy dispersive spectroscopy (EDS) and X-ray diffractometry (XRD). The crystalline deposit contains iron, carbon and oxygen, but the mineral species could not be identified. Guano probably played a role in its formation; the presence of iron may be a consequence of the excretion of iron by the common vampire bat. This enigmatic phenomenon lacks obvious biological significance but may inspire bionic applications. Nothing similar has ever been observed in terrestrial arthropods
Severe and protracted cholestasis in 44 young men taking bodybuilding supplements: assessment of genetic, clinical and chemical risk factors
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149370/1/apt15211_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149370/2/apt15211.pd
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