Surface ozone in the Colorado northern Front Range and the influence of oil and gas development during FRAPPE/DISCOVER-AQ in summer 2014

High mixing ratios of ozone (O3) in the northern Front Range (NFR) of Colorado are not limited to the urban Denver area but were also observed in rural areas where oil and gas activity is the primary source of O3 precursors. On individual days, oil and gas O3 precursors can contribute in excess of 30 ppb to O3 growth and can lead to exceedances of the EPA O3 National Ambient Air Quality Standard. Data used in this study were gathered from continuous surface O3 monitors for June–August 2013–2015 as well as additional flask measurements and mobile laboratories that were part of the FRAPPE/DISCOVER-AQ field campaign of July–August 2014. Overall observed O3 levels during the summer of 2014 were lower than in 2013, likely due to cooler and damper weather than an average summer. This study determined the median hourly surface O3 mixing ratio in the NFR on summer days with limited photochemical production to be approximately 45–55 ppb. Mobile laboratory and flask data collected on three days provide representative case studies of different O3 formation environments in and around Greeley, Colorado. Observations of several gases (including methane, ethane, CO, nitrous oxide) along with O3 are used to identify sources of O3 precursor emissions. A July 23 survey demonstrated low O3 (45–60 ppb) while August 3 and August 13 surveys recorded O3 levels of 75–80 ppb or more. August 3 exemplifies influence of moderate urban and high oil and gas O3 precursor emissions. August 13 demonstrates high oil and gas emissions, low agricultural emissions, and CO measurements that were well correlated with ethane from oil and gas, suggesting an oil and gas related activity as a NOx and O3 precursor source. Low isoprene levels indicated that they were not a significant contributor to O3 precursors measured during the case studies

Ultrasonic Attenuation Measurements in Jet-Engine Titanium Alloys

In the inspection of titanium material intended for use in aircraft engines, a number of unusual phenomena are observed, including significant fluctuations of the amplitude and phase of back-surface echoes and of the amplitudes of pulse-echo signals from nominally identical flaws[1]. Practical implications include a broadening of the probability of detection curves and difficulties in determining the ultrasonic attenuation, a parameter used in interpreting flaw response data. Incorrect determination of attenuation can lead to errors in distance-gain corrections and hence in estimates of the magnitude of the flaw response. In this paper, we report experiments designed to elucidate the mechanisms responsible for these signal fluctuations

Antibiotic use for irreversible pulpitis

Background Irreversible pulpitis, which is characterised by acute and intense pain, is one of the most frequent reasons that patients attend for emergency dental care. Apart from removal of the tooth, the customary way of relieving the pain of irreversible pulpitis is by drilling into the tooth, removing the inflamed pulp (nerve) and cleaning the root canal. However, a significant number of dentists continue to prescribe antibiotics to stop the pain of irreversible pulpitis.This review updates the previous version published in 2016. Objectives To assess the effects of systemic antibiotics for irreversible pulpitis. Search methods We searched Cochrane Oral Health's Trials Register (to 18 February 2019); the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 1) in the Cochrane Library (searched 18 February 2019); MEDLINE Ovid (1946 to 18 February 2019); Embase Ovid (1980 to 18 February 2019); US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (searched 18 February 2019); and the World Health Organization International Clinical Trials Registry Platform (searched 18 February 2019). There were no language restrictions in the searches of the electronic databases. Selection criteria Randomised controlled trials which compared pain relief with systemic antibiotics and analgesics, against placebo and analgesics in the acute preoperative phase of irreversible pulpitis. Data collection and analysis Three review authors screened studies and extracted data independently. We assessed the certainty of the evidence of included studies using GRADE. Pooling of data was not possible and a descriptive summary is presented. Main results No additional trials could be included in this update. One trial at low risk of bias evaluating oral penicillin in combination with analgesics versus placebo with analgesics, involving 40 participants was included in a former update of the review. The certainty of the evidence was rated low for the different outcomes. Our primary outcome was patient‐reported pain (intensity/duration) and pain relief. There was a close parallel distribution of the pain ratings in both the intervention (median 6.0, interquartile range (IQR) 10.5), and for placebo (median 6.0, IQR 9.5) over the seven‐day study period. There was insufficient evidence to claim or refute a benefit for penicillin for pain intensity. There was no significant difference in the mean total number of ibuprofen tablets over the study period: 9.20 (standard deviation (SD) 6.02) in the penicillin group versus 9.60 (SD 6.34) in the placebo group; mean difference ‐0.40 (95% confidence interval (CI) ‐4.23 to 3.43; P = 0.84). This applied equally for the mean total number of Tylenol tablets: 6.90 (SD 6.87) used in the penicillin group versus 4.45 (SD 4.82) in the placebo group; mean difference 2.45 (95% CI ‐1.23 to 6.13; P = 0.19). Our secondary outcome on reporting of adverse events was not addressed in this study

Bifurcation analysis of delay-induced resonances of the El-Nino Southern Oscillation

Models of global climate phenomena of low to intermediate complexity are very useful for providing an understanding at a conceptual level. An important aspect of such models is the presence of a number of feedback loops that feature considerable delay times, usually due to the time it takes to transport energy (for example, in the form of hot/cold air or water) around the globe. In this paper we demonstrate how one can perform a bifurcation analysis of the behaviour of a periodically-forced system with delay in dependence on key parameters. As an example we consider the El-Nino Southern Oscillation (ENSO), which is a sea surface temperature oscillation on a multi-year scale in the basin of the Pacific Ocean. One can think of ENSO as being generated by an interplay between two feedback effects, one positive and one negative, which act only after some delay that is determined by the speed of transport of sea-surface temperature anomalies across the Pacific. We perform here a case study of a simple delayed-feedback oscillator model for ENSO (introduced by Tziperman et al, J. Climate 11 (1998)), which is parametrically forced by annual variation. More specifically, we use numerical bifurcation analysis tools to explore directly regions of delay-induced resonances and other stability boundaries in this delay-differential equation model for ENSO.Comment: as accepted for Proc Roy Soc A, 20 pages, 7 figure

Mean flow instabilities of two-dimensional convection in strong magnetic fields

The interaction of magnetic fields with convection is of great importance in astrophysics. Two well-known aspects of the interaction are the tendency of convection cells to become narrow in the perpendicular direction when the imposed field is strong, and the occurrence of streaming instabilities involving horizontal shears. Previous studies have found that the latter instability mechanism operates only when the cells are narrow, and so we investigate the occurrence of the streaming instability for large imposed fields, when the cells are naturally narrow near onset. The basic cellular solution can be treated in the asymptotic limit as a nonlinear eigenvalue problem. In the limit of large imposed field, the instability occurs for asymptotically small Prandtl number. The determination of the stability boundary turns out to be surprisingly complicated. At leading order, the linear stability problem is the linearisation of the same nonlinear eigenvalue problem, and as a result, it is necessary to go to higher order to obtain a stability criterion. We establish that the flow can only be unstable to a horizontal mean flow if the Prandtl number is smaller than order , where B0 is the imposed magnetic field, and that the mean flow is concentrated in a horizontal jet of width in the middle of the layer. The result applies to stress-free or no-slip boundary conditions at the top and bottom of the layer

Here's looking at you, kid: attention to infant emotional faces in mothers and non-mothers.

Infant facial cues play a critical role in eliciting care and nurturance from an adult caregiver. Using an attentional capture paradigm we investigated attentional processing of adult and infant emotional facial expressions in a sample of mothers (n = 29) and non-mothers (n = 37) to determine whether infant faces were associated with greater task interference. Responses to infant target stimuli were slower than adult target stimuli in both groups. This effect was modulated by parental status, such that mothers compared to non-mothers showed longer response times to infant compared to adult faces. Both groups also responded more slowly to emotional faces, an effect that was more marked for infant emotional faces. Finally, it was found that greater levels of mothers' self-reported parental distress was associated with less task interference when processing infant faces. These findings indicate that for adult women, infant faces in general and emotional infant faces in particular, preferentially engage attention compared to adult faces. However, for mothers, infant faces appear to be more salient in general. Therefore, infant faces may constitute a special class of social stimuli. We suggest that alterations in attentional processing in motherhood may constitute an adaptive behavioural change associated with becoming a parent

Facial recognition during early motherhood: Investigating the persistence of age and affect biases

Converging evidence demonstrates increased levels of sensitivity to infant faces in mothers. This may be reflective of a series of psychological and neurobiological changes that occur in the transition to, and during early, parenthood for the purpose of appropriate caregiving; however, this enhanced infant facial recognition is in contrast with the general adult literature regarding facial processing. In the current study, we aimed to replicate a prior study of emotion facial recognition in pregnant women in a sample of mothers with children under a year old, utilizing a paradigm in which adult and infant faces gradually changed from neutral expressions to either happy or sad expressions. Mothers were faster at the recognition of adult faces in comparison to infant faces, and were also faster at happy faces in comparison to sad faces. Results are discussed in context of the current processing literature regarding the perinatal period, and implications for the persistence of the own-age bias and happy face advantage are considered

Fascicle localisation within peripheral nerves through evoked activity recordings: A comparison between electrical impedance tomography and multi-electrode arrays

BACKGROUND: The lack of understanding of fascicular organisation in peripheral nerves limits the potential of vagus nerve stimulation therapy. Two promising methods may be employed to identify the functional anatomy of fascicles within the nerve: fast neural electrical impedance tomography (EIT), and penetrating multi-electrode arrays (MEA). These could provide a means to image the compound action potential within fascicles in the nerve. NEW METHOD: We compared the ability to localise fascicle activity between silicon shanks (SS) and carbon fibre (CF) multi-electrode arrays and fast neural EIT, with micro-computed tomography (MicroCT) as an independent reference. Fast neural EIT in peripheral nerves was only recently developed and MEA technology has been used only sparingly in nerves and not for source localisation. Assessment was performed in rat sciatic nerves while evoking neural activity in the tibial and peroneal fascicles. RESULTS: Recorded compound action potentials were larger with CF compared to SS (∼700μV vs ∼300μV); however, background noise was greater (6.3μV vs 1.7μV) leading to lower SNR. Maximum spatial discrimination between Centres-of-Mass of fascicular activity was achieved by fast neural EIT (402±30μm) and CF MEA (414±123μm), with no statistical difference between MicroCT (625±17μm) and CF (p>0.05) and between CF and EIT (p>0.05). Compared to CF MEAs, SS MEAs had a lower discrimination power (103±51μm, p<0.05). COMPARISON WITH EXISTING METHODS: EIT and CF MEAs showed localisation power closest to MicroCT. Silicon MEAs adopted in this study failed to discriminate fascicle location. Re-design of probe geometry may improve results. CONCLUSIONS: Nerve EIT is an accurate tool for assessment of fascicular position within nerves. Accuracy of EIT and CF MEA is similar to the reference method. We give technical recommendations for performing multi-electrode recordings in nerves

The 5.2 ka climate event: Evidence from stable isotope and multi-proxy palaeoecological peatland records in Ireland

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Evidence for a major climate event at 5.2 ka has been reported globally and is associated with considerable societal disruption, but is poorly characterised in northwest Europe. This event forms part of a broader period of re-organisation in the Earth's ocean-atmosphere circulation system between 6 and 5 ka. This study tests the nature and timing of the event in northwest Europe, a region highly sensitive to change in meridional overturning circulation and mid-latitude westerly airflow. Here we report three high-resolution Irish multi-proxy records obtained from ombrotrophic peatlands that have robust chronological frameworks. We identify the 5.2 ka event by a sustained decrease in δ 18 O cellulose at all three sites, with additional and parallel changes in δ 13 C cellulose and palaeoecological (testate amoebae, plant macrofossil and humification) data from two sites in northern Ireland. Data from Sluggan Moss demonstrate a particularly coherent shift towards wetter conditions. These data support the hypothesis that the event was caused by a prolonged period of positive North Atlantic Oscillation conditions, resulting in pervasive cyclonic weather patterns across northwest Europe, increasing precipitation over Ireland.This research was carried out while T.P.R. held UK Natural Environment Research Council studentship at the University of Exeter (NE/G524328/1) and T.J.D held a studentship at the University of Southampton tied to the NERC RAPID Programme (NER/T/S/2002/00460). Radiocarbon support was provided by the NERC 14C Steering Committee (Allocation No.: 1523.0910), the NERC RAPID Programme and the Irish Quaternary Association via the IQUA Bill Watts 14Chrono award

How many neurons are sufficient for perception of cortical activity?

Many theories of brain function assume that information is encoded and behaviour is controlled through sparse, distributed patterns of activity. It is therefore crucial to place a lower bound on the amount of neural activity that can drive behaviour and to understand how neuronal networks operate within these constraints. We use an all-optical approach to test this lower limit by driving behaviour with targeted two-photon optogenetic activation of small ensembles of L2/3 pyramidal neurons in mouse barrel cortex while using two-photon calcium imaging to record the impact on the local network. By precisely titrating the number of neurons in activated ensembles we demonstrate that the lower bound for detection of cortical activity is ~14 pyramidal neurons. We show that there is a very steep sigmoidal relationship between the number of activated neurons and behavioural output, saturating at only ~37 neurons, and that this relationship can shift with learning. By simultaneously measuring activity in the local network, we show that the activation of stimulated ensembles is balanced by the suppression of neighbouring neurons. This surprising behavioural sensitivity in the face of potent network suppression supports the sparse coding hypothesis and suggests that perception of cortical activity balances a trade-off between minimizing the impact of noise while efficiently detecting relevant signals