Free-hand sketch synthesis with deformable stroke models

We present a generative model which can automatically summarize the stroke composition of free-hand sketches of a given category. When our model is fit to a collection of sketches with similar poses, it discovers and learns the structure and appearance of a set of coherent parts, with each part represented by a group of strokes. It represents both consistent (topology) as well as diverse aspects (structure and appearance variations) of each sketch category. Key to the success of our model are important insights learned from a comprehensive study performed on human stroke data. By fitting this model to images, we are able to synthesize visually similar and pleasant free-hand sketches

Validation of the Chronic Pain Acceptance Questionnaire-8 in an Australian pain clinic sample

Background: Recently, an 8-item short-form version of the Chronic Pain Acceptance Questionnaire (CPAQ-8) was developed predominantly in an internet sample. Further investigation of the factor structure in a multidisciplinary pain clinic sample is required. Investigation of the concurrent validity of the CPAQ-8 after accounting for the effects of variables commonly measured in the pain clinic setting is also necessary. Purpose: This study examines the factor structure and concurrent validity of the CPAQ-8 in a sample of treatmentseeking patients who attended a multidisciplinary pain clinic. Methods: Participants were 334 patients who attended an Australian multidisciplinary pain service. Participants completed the CPAQ, a demographic questionnaire, and measures of patient adjustment and functioning. Results: Confirmatory factor analysis identified a two-factor 8-item model consisting of Activity Engagement and Pain Willingness factors (SRMR=0.039, RMSEA=0.063, CFI=0.973, TLI=0.960) was superior to both the CPAQ and CPAQ with an item removed. The CPAQ and CPAQ-8 total scores were highly correlated (r=0.93). After accounting for pain intensity, the CPAQ-8 was a significant predictor of depression, anxiety, stress, and disability. The subscales of the CPAQ-8 were both unique contributors to depression and disability in regression analyses, after accounting for pain intensity and kinesiophobia, and after accounting for pain intensity and catastrophizing. Conclusions: The CPAQ-8 has a sound factor structure and similar psychometric properties to the CPAQ; it may have clinical utility as a measure of pain acceptance in treatmentseeking, chronic pain patients

The use of contextualised standardised client simulation to develop clinical reasoning in final year veterinary students

Clinical reasoning is an important skill for veterinary students to develop before graduation. Simulation has been studied in medical education as a method for developing clinical reasoning in students, but evidence supporting it is limited. This study involved the creation of a contextualized, standardized client simulation session that aimed to improve the clinical reasoning ability and confidence of final-year veterinary students. Sixty-eight participants completed three simulated primary-care consultations, with the client played by an actor and the pet by a healthy animal. Survey data showed that all participants felt that the session improved their clinical decision-making ability. Quantitative clinical reasoning self-assessment, performed using a validated rubric, triangulated this finding, showing an improvement in students’ perception of several components of their clinical reasoning skill level from before the simulation to after it. Blinded researcher analysis of the consultation video recordings found that students showed a significant increase in ability on the history-taking and making-sense-of-data (including formation of a differential diagnosis) components of the assessment rubric. Thirty students took part in focus groups investigating their experience with the simulation. Two themes arose from thematic analysis of these data: variety of reasoning methods and “It’s a different way of thinking.” The latter highlights differences between the decision making students practice during their time in education and the decision making they will use once they are in practice. Our findings suggest that simulation can be used to develop clinical reasoning in veterinary students, and they demonstrate the need for further research in this area

Antarctic sea ice region as a source of biogenic organic nitrogen in aerosols

Dall'Osto, Manuel ... et al.-- 10 pages, 5 figuresClimate warming affects the development and distribution of sea ice, but at present the evidence of polar ecosystem feedbacks on climate through changes in the atmosphere is sparse. By means of synergistic atmospheric and oceanic measurements in the Southern Ocean near Antarctica, we present evidence that the microbiota of sea ice and sea ice-influenced ocean are a previously unknown significant source of atmospheric organic nitrogen, including low molecular weight alkyl-amines. Given the keystone role of nitrogen compounds in aerosol formation, growth and neutralization, our findings call for greater chemical and source diversity in the modelling efforts linking the marine ecosystem to aerosol-mediated climate effects in the Southern OceanThe cruise was funded by the Spanish Ministry of Economy through projects PEGASO (CTM2012-37615) and Bio-Nuc (CGL2013-49020-R), and by the EU though the FP7-PEOPLE-2013-IOF programme (Project number 624680, MANU – Marine Aerosol NUcleations). [...] The NUI Galway and ISAC-CNR Bologna groups acknowledge funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) project BACCHUS under grant agreement n° 603445. The work was further supported by the CNR (Italy) under AirSEaLab: Progetto Laboratori Congiunti. The National Centre for Atmospheric Science NCAS Birmingham group is funded by the UK Natural Environment Research Council. [...] CC, MFF and RA acknowledge funding from the Marine Institute, University of Plymouth to enable participation in PEGASOPeer Reviewe

Understanding atmospheric organic aerosols via factor analysis of aerosol mass spectrometry: a review

Organic species are an important but poorly characterized constituent of airborne particulate matter. A quantitative understanding of the organic fraction of particles (organic aerosol, OA) is necessary to reduce some of the largest uncertainties that confound the assessment of the radiative forcing of climate and air quality management policies. In recent years, aerosol mass spectrometry has been increasingly relied upon for highly time-resolved characterization of OA chemistry and for elucidation of aerosol sources and lifecycle processes. Aerodyne aerosol mass spectrometers (AMS) are particularly widely used, because of their ability to quantitatively characterize the size-resolved composition of submicron particles (PM1). AMS report the bulk composition and temporal variations of OA in the form of ensemble mass spectra (MS) acquired over short time intervals. Because each MS represents the linear superposition of the spectra of individual components weighed by their concentrations, multivariate factor analysis of the MS matrix has proved effective at retrieving OA factors that offer a quantitative and simplified description of the thousands of individual organic species. The sum of the factors accounts for nearly 100% of the OA mass and each individual factor typically corresponds to a large group of OA constituents with similar chemical composition and temporal behavior that are characteristic of different sources and/or atmospheric processes. The application of this technique in aerosol mass spectrometry has grown rapidly in the last six years. Here we review multivariate factor analysis techniques applied to AMS and other aerosol mass spectrometers, and summarize key findings from field observations. Results that provide valuable information about aerosol sources and, in particular, secondary OA evolution on regional and global scales are highlighted. Advanced methods, for example a-priori constraints on factor mass spectra and the application of factor analysis to combined aerosol and gas phase data are discussed. Integrated analysis of worldwide OA factors is used to present a holistic regional and global description of OA. Finally, different ways in which OA factors can constrain global and regional models are discussed

Coral reef annihilation, persistence and recovery at Earth’s youngest volcanic island

The structure and function of coral reef ecosystems is increasingly compromised by multiple stressors, even in the most remote locations. Severe, acute disturbances such as volcanic eruptions represent extreme events that can annihilate entire reef ecosystems, but also provide unique opportunities to examine ecosystem resilience and recovery. Here, we examine the destruction, persistence and initial recovery of reefs associated with the hydro-magmatic eruption that created Earth’s newest landmass, the Hunga Tonga–Hunga Ha’apai volcanic island. Despite extreme conditions associated with the eruption, impacts on nearby reefs were spatially variable. Importantly, even heavily affected reefs showed signs of rapid recovery driven by high recruitment, likely from local refuges. The remote location and corresponding lack of additional stressors likely contribute to the resilience of Hunga’s reefs, suggesting that in the absence of chronic anthropogenic stressors, coral reefs can be resilient to one of the largest physical disturbances on Earth

Cloud activating properties of aerosol observed during CELTIC

Measurements of aerosol size distribution, chemical composition, and cloud condensation nuclei (CCN) concentration were performed during the Chemical Emission, Loss, Transformation, and Interactions with Canopies (CELTIC) field program at Duke Forest in North Carolina. A kinetic model of the cloud activation of ambient aerosol in the chamber of the CCN instrument was used to perform an aerosol-CCN closure study. This study advances prior investigations by employing a novel fitting algorithm that was used to integrate scanning mobility particle sizer (SMPS) measurements of aerosol number size distribution and aerosol mass spectrometer (AMS) measurements of the mass size distribution for sulfate, nitrate, ammonium, and organics into a single, coherent description of the ambient aerosol in the size range critical to aerosol activation (around 100-nm diameter). Three lognormal aerosol size modes, each with a unique internally mixed composition, were used as input into the kinetic model. For the two smaller size modes, which control CCN number concentration, organic aerosol mass fractions for the defined cases were between 58% and 77%. This study is also unique in that the water vapor accommodation coefficient was estimated based on comparing the initial timing for CCN activation in the instrument chamber with the activation predicted by the kinetic model. The kinetic model overestimated measured CCN concentrations, especially under polluted conditions. Prior studies have attributed a positive model bias to an incomplete understanding of the aerosol composition, especially the role of organics in the activation process. This study shows that including measured organic mass fractions with an assumed organic aerosol speciation profile (pinic acid, fulvic acid, and levoglucosan) and an assumed organic aerosol solubility of 0.02 kg kg-1 still resulted in a significant model positive bias for polluted case study periods. The slope and y intercept for the CCN predicted versus CCN observed regression was found to be 1.9 and -180 cm-3, respectively. The overprediction generally does not exceed uncertainty limits but is indicative that a bias exists in the measurements or application of model. From this study, uncertainties in the particle number and mass size distributions as the cause for the model bias can be ruled out. The authors are also confident that the model is including the effects of growth kinetics on predicted activated number. However, one cannot rule out uncertainties associated with poorly characterized CCN measurement biases, uncertainties in assumed organic solubility, and uncertainties in aerosol mixing state. Sensitivity simulations suggest that assuming either an insoluble organic fraction or external aerosol mixing were both sufficient to reconcile the model bias. © 2007 American Meteorological Society

An overview and early results from the HOMEChem indoor air chemistry field campaign

The HOMEChem (House Observations of Microbial and Environmental Chemistry) is a collaborative indoor air chemistry field study to be performed in June 2018 at the UTest House, a manufactured research house located in the University of Texas at Austin's research campus. The HOMEChem experiment investigates the effects of building occupants and their activities, such as cooking and cleaning, on the chemistry of the gas phase, particle phase, and surfaces in a simulated home environment. Specifically, this study focuses on the presence of organic species, chemical oxidants, and reactive nitrogen species indoors compared to outdoor levels. This study incorporates state-of the art atmospheric chemistry instrumentation from multiple research groups to build a shared dataset from those measurements

Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): Emissions of trace gases and light-absorbing carbon from wood and dung cooking fires, garbage and crop residue burning, brick kilns, and other sources

The Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) campaign took place in and around the Kathmandu Valley and in the Indo-Gangetic Plain (IGP) of southern Nepal during April 2015. The source characterization phase targeted numerous important but undersampled (and often inefficient) combustion sources that are widespread in the developing world such as cooking with a variety of stoves and solid fuels, brick kilns, open burning of municipal solid waste (a.k.a. trash or garbage burning), crop residue burning, generators, irrigation pumps, and motorcycles. NAMaSTE produced the first, or rare, measurements of aerosol optical properties, aerosol mass, and detailed trace gas chemistry for the emissions from many of the sources. This paper reports the trace gas and aerosol measurements obtained by Fourier transform infrared (FTIR) spectroscopy, whole-air sampling (WAS), and photoacoustic extinctiometers (PAX; 405 and 870nm) based on field work with a moveable lab sampling authentic sources. The primary aerosol optical properties reported include emission factors (EFs) for scattering and absorption coefficients (EF Bscat, EF Babs, inm2kg-1 fuel burned), single scattering albedos (SSAs), and absorption Ångström exponents (AAEs). From these data we estimate black and brown carbon (BC, BrC) emission factors (gkg-1 fuel burned). The trace gas measurements provide EFs (gkg-1) for CO2, CO, CH4, selected non-methane hydrocarbons up to C10, a large suite of oxygenated organic compounds, NH3, HCN, NOx, SO2, HCl, HF, etc. (up to ∼ 80 gases in all). The emissions varied significantly by source, and light absorption by both BrC and BC was important for many sources. The AAE for dung-fuel cooking fires (4.63±0.68) was significantly higher than for wood-fuel cooking fires (3.01±0.10). Dung-fuel cooking fires also emitted high levels of NH3 (3.00±1.33gkg-1), organic acids (7.66±6.90gkg-1), and HCN (2.01±1.25gkg-1), where the latter could contribute to satellite observations of high levels of HCN in the lower stratosphere above the Asian monsoon. HCN was also emitted in significant quantities by several non-biomass burning sources. BTEX compounds (benzene, toluene, ethylbenzene, xylenes) were major emissions from both dung- (∼4.5gkg-1) and wood-fuel (∼1.5gkg-1) cooking fires, and a simple method to estimate indoor exposure to the many measured important air toxics is described. Biogas emerged as the cleanest cooking technology of approximately a dozen stove-fuel combinations measured. Crop residue burning produced relatively high emissions of oxygenated organic compounds (∼12gkg-1) and SO2 (2.54±1.09gkg-1). Two brick kilns co-firing different amounts of biomass with coal as the primary fuel produced contrasting results. A zigzag kiln burning mostly coal at high efficiency produced larger amounts of BC, HF, HCl, and NOx, with the halogenated emissions likely coming from the clay. The clamp kiln (with relatively more biomass fuel) produced much greater quantities of most individual organic gases, about twice as much BrC, and significantly more known and likely organic aerosol precursors. Both kilns were significant SO2 sources with their emission factors averaging 12.8±0.2gkg-1. Mixed-garbage burning produced significantly more BC (3.3±3.88gkg-1) and BTEX (∼4.5gkg-1) emissions than in previous measurements. For all fossil fuel sources, diesel burned more efficiently than gasoline but produced larger NOx and aerosol emission factors. Among the least efficient sources sampled were gasoline-fueled motorcycles during start-up and idling for which the CO EF was on the order of ∼700gkg-1 - or about 10 times that of a typical biomass fire. Minor motorcycle servicing led to minimal if any reduction in gaseous pollutants but reduced particulate emissions, as detailed in a companion paper (Jayarathne et al., 2016). A small gasoline-powered generator and an "insect repellent fire" were also among the sources with the highest emission factors for pollutants. These measurements begin to address the critical data gap for these important, undersampled sources, but due to their diversity and abundance, more work is needed

Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): Emissions of trace gases and light-absorbing carbon from wood and dung cooking fires, garbage and crop residue burning, brick kilns, and other sources

The Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) campaign took place in and around the Kathmandu Valley and in the Indo-Gangetic Plain (IGP) of southern Nepal during April 2015. The source characterization phase targeted numerous important but undersampled (and often inefficient) combustion sources that are widespread in the developing world such as cooking with a variety of stoves and solid fuels, brick kilns, open burning of municipal solid waste (a.k.a. trash or garbage burning), crop residue burning, generators, irrigation pumps, and motorcycles. NAMaSTE produced the first, or rare, measurements of aerosol optical properties, aerosol mass, and detailed trace gas chemistry for the emissions from many of the sources. This paper reports the trace gas and aerosol measurements obtained by Fourier transform infrared (FTIR) spectroscopy, whole-air sampling (WAS), and photoacoustic extinctiometers (PAX; 405 and 870nm) based on field work with a moveable lab sampling authentic sources. The primary aerosol optical properties reported include emission factors (EFs) for scattering and absorption coefficients (EF Bscat, EF Babs, inm2kg-1 fuel burned), single scattering albedos (SSAs), and absorption Ångström exponents (AAEs). From these data we estimate black and brown carbon (BC, BrC) emission factors (gkg-1 fuel burned). The trace gas measurements provide EFs (gkg-1) for CO2, CO, CH4, selected non-methane hydrocarbons up to C10, a large suite of oxygenated organic compounds, NH3, HCN, NOx, SO2, HCl, HF, etc. (up to ∼ 80 gases in all). The emissions varied significantly by source, and light absorption by both BrC and BC was important for many sources. The AAE for dung-fuel cooking fires (4.63±0.68) was significantly higher than for wood-fuel cooking fires (3.01±0.10). Dung-fuel cooking fires also emitted high levels of NH3 (3.00±1.33gkg-1), organic acids (7.66±6.90gkg-1), and HCN (2.01±1.25gkg-1), where the latter could contribute to satellite observations of high levels of HCN in the lower stratosphere above the Asian monsoon. HCN was also emitted in significant quantities by several non-biomass burning sources. BTEX compounds (benzene, toluene, ethylbenzene, xylenes) were major emissions from both dung- (∼4.5gkg-1) and wood-fuel (∼1.5gkg-1) cooking fires, and a simple method to estimate indoor exposure to the many measured important air toxics is described. Biogas emerged as the cleanest cooking technology of approximately a dozen stove-fuel combinations measured. Crop residue burning produced relatively high emissions of oxygenated organic compounds (∼12gkg-1) and SO2 (2.54±1.09gkg-1). Two brick kilns co-firing different amounts of biomass with coal as the primary fuel produced contrasting results. A zigzag kiln burning mostly coal at high efficiency produced larger amounts of BC, HF, HCl, and NOx, with the halogenated emissions likely coming from the clay. The clamp kiln (with relatively more biomass fuel) produced much greater quantities of most individual organic gases, about twice as much BrC, and significantly more known and likely organic aerosol precursors. Both kilns were significant SO2 sources with their emission factors averaging 12.8±0.2gkg-1. Mixed-garbage burning produced significantly more BC (3.3±3.88gkg-1) and BTEX (∼4.5gkg-1) emissions than in previous measurements. For all fossil fuel sources, diesel burned more efficiently than gasoline but produced larger NOx and aerosol emission factors. Among the least efficient sources sampled were gasoline-fueled motorcycles during start-up and idling for which the CO EF was on the order of ∼700gkg-1 - or about 10 times that of a typical biomass fire. Minor motorcycle servicing led to minimal if any reduction in gaseous pollutants but reduced particulate emissions, as detailed in a companion paper (Jayarathne et al., 2016). A small gasoline-powered generator and an "insect repellent fire" were also among the sources with the highest emission factors for pollutants. These measurements begin to address the critical data gap for these important, undersampled sources, but due to their diversity and abundance, more work is needed