145 research outputs found
Photocatalytic treatment of textile dyehouse effluents with simulated and natural solar light
Screening for atrial fibrillation with or without general practice involvement: a controlled study
Background: There has been a drive to increase atrial fibrillation (AF) detection in general practice. However, one-off, opportunistic testing can miss paroxysmal AF and requires significant resource. Paroxysmal AF can be detected through screening that involves repeated ECGs over a period of time, although it is unclear whether screening would need to be led by general practice, and how much support participants require. We aimed to investigate whether AF screening can be delivered remotely by a centralised administration instead of general practice, and to determine the level of support required. Methods: We undertook a controlled comparator study with secondary randomisation in three English general practices. We invited people aged ≥ 70 years to use a hand-held ECG device four times daily for three weeks. Participants were allocated to practice-led or administrator-led screening, with administrator-led support randomised to three different levels. We compared quantity and quality of ECGs obtained in each arm. The primary outcome was proportion of screened participants who recorded ≥ 56 adequate-quality ECGs (2/3 of possible ECGs). Results: Of 288 screened participants, 59 participants received practice-led screening with a telephone consultation to explain the device. The remainder received administrator-led screening: 81 were automatically given a consultation; 74 were offered a consultation, and 74 were not offered a consultation. Most screened participants (280/288, 97.2%) recorded ≥ 56 adequate-quality ECGs. This proportion did not vary significantly between practice-led and administrator-led screening (100.0% vs. 98.8%), or between support levels (94.6% to 98.8%). Practice-led screening led to slightly more adequate-quality ECGs (mean: 83.9 vs 78.3, p < 0.001). Conclusions: AF screening can be successfully delivered remotely, outside general practice, with minimal support
Integration of physical and mental health services for children and young people with eating disorders and functional symptom disorders:discrete choice experiment
BACKGROUND: Given the increasing recognition of the value of greater integration of physical and mental health services for children and young people, we aimed to evaluate preferences among parents for the characteristics associated with integrated health service provision for two conditions (eating disorders, functional symptom disorders).METHODS: Two discrete choice experiments (DCEs) were conducted, using electronic surveys. Participants were adult parents of children and young people. Choice scenarios were based on five attributes for the eating disorders study, and four attributes for the functional symptom disorders study.RESULTS: Two hundred parents participated in each DCE. For eating disorders, days missed from school in the last year was the attribute valued most highly, followed by days in hospital in the last year, costs to the NHS, functioning, and interaction with peers with eating disorders. Respondents were willing to trade £531 of costs to the NHS for one less day missed from school. For functional symptom disorders, time to diagnosis was valued most highly, followed by days missed from school while obtaining a diagnosis, reservations about seeing a mental health practitioner, and costs of diagnosis to the NHS. Respondents were willing to trade £4237 of costs to the NHS to wait one month less for a diagnosis.CONCLUSION: Respondents' preferences were largely consistent with the planned goals of integrating physical and mental health services. Our findings show the factors which ought to be considered when designing new integrated pathways and evaluating them.</p
UV and simulated solar photodegradation of 17α-ethynylestradiol in secondary-treated wastewater by hydrogen peroxide or iron addition
The extensive use of estrogens and their release, through various pathways, into the environment, constitutes an emerging environmental problem that poses serious threats onto public health. In this work the efficiency of UVC/H2O2 and solar/Fe2+ treatment to degrade 17α-ethynylestradiol (EE2) in environmentally relevant concentrations of 100 μg/L in secondary-treated wastewater matrices was investigated. Also, photolytic treatment was performed under different irradiation sources, namely UVC, UVA and simulated solar light. The effect of H2O2 (0–20 mg/L) and Fe2+ (0–15 mg/L) concentration was investigated and, at optimal operating parameters, EE2 removal was 100% after 15 min of UVC/H2O2 treatment, while EE2 removal reached 86% after 60 min of solar/Fe2+ treatment. In addition, the effect of water matrix and pH was studied. Total organic carbon (TOC) and yeast estrogen screening (YES) measurements showed the formation of stable intermediate products during EE2 treatment and an attempt to elucidate the reaction pathways and mechanisms through the identification of transformation products (TPs) by means of UPLC–MS/MS was made. Several TPs, including quinone methide and 1,2-quinone derivatives, were identified and competing pathways were suggested, in which hydroxylation, alkylation, dealkylation, demethylation and dehydroxylation, amongst others were described as major transformation mechanisms
Life cycle assessment of the environmental performance of conventional and organic methods of open field pepper cultivation
Summarization: As the scale of the organic cultivation sector keeps increasing, there is growing demand for reliable data on organic agriculture and its effect on the environment. Conventional agriculture uses chemical fertilizers and pesticides, whilst organic cultivation mainly relies on crop rotation and organic fertilizers. The aim of this work is to quantify and compare the environmental sustainability of typical conventional and organic pepper cultivation systems. Methods: Two open field pepper cultivations, both located in the Anthemountas basin, Northern Greece, are selected as case studies. Life cycle assessment (LCA) is used to quantify the overall environmental footprint and identify particular environmental weaknesses (i.e. unsustainable practices) of each cultivation system. Results are analysed at both midpoint and endpoint levels in order to obtain a comprehensive overview of the environmental sustainability of each system. Attributional LCA (ALCA) is employed to identify emissions associated with the life cycles of the two systems. Results are presented for problem-oriented (midpoint) and damage-oriented (endpoint) approaches, using ReCiPe impact assessment. Results and discussion: At midpoint level, conventional cultivation exhibits about threefold higher environmental impact on freshwater eutrophication, than organic cultivation. This arises from the extensive use of nitrogen and phosphorus-based fertilizers, with consequent direct emissions to the environment. The remaining impact categories are mainly affected by irrigation, with associated indirect emissions linked to electricity production. At endpoint level, the main hotspots identified for conventional cultivation are irrigation and fertilizing, due to intensive use of chemical fertilizers and (to a lesser degree) pesticides. For organic pepper cultivation, the main environmental hotspots are irrigation, machinery use, and manure loading and spreading processes. Of these, the highest score for irrigation derives from the heavy electricity consumption required for groundwater pumping associated with the fossil-fuel-dependent Greek electricity mix. Conclusions: Organic and conventional cultivation systems have similar total environmental impacts per unit of product, with organic cultivation achieving lower environmental impacts in ‘freshwater eutrophication’, ‘climate change’, ‘terrestrial acidification’ and ‘marine eutrophication’ categories. Conventional cultivation has a significantly greater effect on the freshwater eutrophication impact category, due to phosphate emissions arising from application of chemical fertilizers.Presented on: International Journal of Life Cycle Assessmen
The Repeating Flaring Activity of Blazar AO 0235+164
Context. Blazar AO 0235+164, located at redshift z = 0.94, has undergone
several sharp multi-spectral-range flaring episodes during the last decades. In
particular, the episodes peaking in 2008 and 2015, that received extensive
multi-wavelength coverage, exhibited interesting behavior.
Aims. We study the actual origin of these two observed flares by constraining
the properties of the observed photo-polarimetric variability, those of the
broad-band spectral energy-distribution and the observed time-evolution
behavior of the source as seen by ultra-high resolution total-flux and
polarimetric Very-long-baseline interferometry (VLBI) imaging.
Methods. The analysis of VLBI images allows us to constrain kinematic and
geometrical parameters of the 7 mm jet. We use the Discrete Correlation
Function to compute the statistical correlation and the delays between emission
at different spectral ranges. Multi-epoch modeling of the spectral energy
distributions allows us to propose specific models of emission; in particular
for the unusual spectral features observed in this source in the X-ray region
of the spectrum during strong multi spectral-range flares.
Results. We find that these X-ray spectral features can be explained by an
emission component originating in a separate particle distribution than the one
responsible for the two standard blazar bumps. This is in agreement with the
results of our correlation analysis that do not find a strong correlation
between the X-rays and the remaining spectral ranges. We find that both
external Compton dominated and synchrotron self-Compton dominated models can
explain the observed spectral energy distributions. However, synchrotron
self-Compton models are strongly favored by the delays and geometrical
parameters inferred from the observations
Dual molecular mechanisms govern escape at immunodominant HLA A2-restricted HIV epitope
Serial accumulation of mutations to fixation in the SLYNTVATL (SL9) immunodominant, HIV p17 Gag-derived, HLA A2-restricted CTL epitope produce the SLFNTIAVL triple mutant ‘ultimate’ escape variant. These mutations in solvent-exposed residues are believed to interfere with TCR recognition, although confirmation has awaited structural verification. Here, we solved a TCR co-complex structure with SL9 and the triple escape mutant to determine the mechanism of immune escape in this eminent system. We show that, in contrast to prevailing hypotheses, the main TCR contact residue is 4N and the dominant mechanism of escape is not via lack of TCR engagement. Instead, mutation of solvent exposed residues in the peptide destabilize the peptide-HLA and reduce peptide density at the cell surface. These results highlight the extraordinary lengths that HIV employs to evade detection by high-affinity TCRs with a broad peptide-binding footprint and necessitate reevaluation of this exemplar model of HIV TCR escape
Observations of Low and Intermediate Spectral Peak Blazars with the Imaging X-Ray Polarimetry Explorer
We present X-ray polarimetry observations from the Imaging X-ray Polarimetry Explorer (IXPE) of three low spectral peak and one intermediate spectral peak blazars, namely 3C 273, 3C 279, 3C 454.3, and S5 0716+714. For none of these objects was IXPE able to detect X-ray polarization at the 3σ level. However, we placed upper limits on the polarization degree at ∼10%–30%. The undetected polarizations favor models where the X-ray band is dominated by unpolarized photons upscattered by relativistic electrons in the jets of blazars, although hadronic models are not completely eliminated. We discuss the X-ray polarization upper limits in the context of our contemporaneous multiwavelength polarization campaigns
Monitoring the Morphology of M87* in 2009–2017 with the Event Horizon Telescope
The Event Horizon Telescope (EHT) has recently delivered the first resolved images of M87*, the supermassive black hole in the center of the M87 galaxy. These images were produced using 230 GHz observations performed in 2017 April. Additional observations are required to investigate the persistence of the primary image feature—a ring with azimuthal brightness asymmetry—and to quantify the image variability on event horizon scales. To address this need, we analyze M87* data collected with prototype EHT arrays in 2009, 2011, 2012, and 2013. While these observations do not contain enough information to produce images, they are sufficient to constrain simple geometric models. We develop a modeling approach based on the framework utilized for the 2017 EHT data analysis and validate our procedures using synthetic data. Applying the same approach to the observational data sets, we find the M87* morphology in 2009–2017 to be consistent with a persistent asymmetric ring of ~40 μas diameter. The position angle of the peak intensity varies in time. In particular, we find a significant difference between the position angle measured in 2013 and 2017. These variations are in broad agreement with predictions of a subset of general relativistic magnetohydrodynamic simulations. We show that quantifying the variability across multiple observational epochs has the potential to constrain the physical properties of the source, such as the accretion state or the black hole spin
Gravitational Test beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole
The 2017 Event Horizon Telescope (EHT) observations of the central source in M87 have led to the first measurement of the size of a black-hole shadow. This observation offers a new and clean gravitational test of the black-hole metric in the strong-field regime. We show analytically that spacetimes that deviate from the Kerr metric but satisfy weak-field tests can lead to large deviations in the predicted black-hole shadows that are inconsistent with even the current EHT measurements. We use numerical calculations of regular, parametric, non-Kerr metrics to identify the common characteristic among these different parametrizations that control the predicted shadow size. We show that the shadow-size measurements place significant constraints on deviation parameters that control the second post-Newtonian and higher orders of each metric and are, therefore, inaccessible to weak-field tests. The new constraints are complementary to those imposed by observations of gravitational waves from stellar-mass sources
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