On UT 29 June 2015, the occultation by Pluto of a bright star (r′ = 11.9) was observed from the Stratospheric Observatory for Infrared Astronomy (SOFIA) and several ground-based stations in New ...Zealand and Australia. Pre-event astrometry allowed for an in-flight update to the SOFIA team with the result that SOFIA was deep within the central flash zone (~22 km from center). Analysis of the combined data leads to the result that Pluto's middle atmosphere is essentially unchanged from 2011 and 2013 (Person et al. 2013; Bosh et al. 2015); there has been no significant expansion or contraction of the atmosphere. Additionally, our multi-wavelength observations allow us to conclude that a haze component in the atmosphere is required to reproduce the light curves obtained. This haze scenario has implications for understanding the photochemistry of Pluto's atmosphere.
On 2011 February 1 the Kepler mission released data for 156,453 stars observed from the beginning of the science observations on 2009 May 2 through September 16. There are 1235 planetary candidates ...with transit-like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates are separated into five class sizes: 68 candidates of approximately Earth-size (R p < 1.25 R {circled plus}), 288 super-Earth-size (1.25 R {circled plus} <= R p < 2 R {circled plus}), 662 Neptune-size (2 R {circled plus} <= R p < 6 R {circled plus}), 165 Jupiter-size (6 R {circled plus} <= R p < 15 R {circled plus}), and 19 up to twice the size of Jupiter (15 R {circled plus} <= R p < 22 R {circled plus}). In the temperature range appropriate for the habitable zone, 54 candidates are found with sizes ranging from Earth-size to larger than that of Jupiter. Six are less than twice the size of the Earth. Over 74% of the planetary candidates are smaller than Neptune. The observed number versus size distribution of planetary candidates increases to a peak at two to three times the Earth-size and then declines inversely proportional to the area of the candidate. Our current best estimates of the intrinsic frequencies of planetary candidates, after correcting for geometric and sensitivity biases, are 5% for Earth-size candidates, 8% for super-Earth-size candidates, 18% for Neptune-size candidates, 2% for Jupiter-size candidates, and 0.1% for very large candidates; a total of 0.34 candidates per star. Multi-candidate, transiting systems are frequent; 17% of the host stars have multi-candidate systems, and 34% of all the candidates are part of multi-candidate systems.
Here, the degradation of polymer electrolyte membrane fuel cells (PEMFCs) catalyst layers used for heavy-duty vehicles was examined using a catalyst-specific accelerated stress test (AST). High ...surface area carbon supported dispersed Pt (Pt/HSC), annealed Pt (a-Pt/HSC) and PtCo (PtCo/HSC) alloy catalysts were examined over the course of 90,000 cycles by measuring changes in mass activity, O2 transport resistance, electrochemical active surface area (ECSA), catalyst accessibility and ionomer-electrocatalyst interactions. Compared to a-Pt/HSC and Pt/HSC catalyst, the PtCo/HSC showed better initial mass activity, a larger initial mass transport loss, and faster degradation after the first 30k AST cycles, as a large portion of Co leached out during potential cycling. Pt/HSC showed higher initial performance relative to a-Pt/HSC but had faster degradation. STEM characterizations show that the ECSA losses are largely related to Pt dissolution resulting in either catalyst particle growth via the Ostwald ripening mechanism or redeposition in the membrane. Catalyst accessibility measurements showed decreased RH sensitivity for all three samples, while CO impedance measurements revealed a decrease in both Pt-water and carbon-water interactions. This implies that, Pt is either preferentially redepositing on the exterior of the carbon support, or that the ionomer is undergoing morphological changes enabling the enhanced intrusion of mesopores.
Mosses account for 75% of the annual phosphorus accumulation in aboveground parts of an Alaskan black spruce forest, although they comprise only 17% of the phosphorus pool in aboveground vegetation. ...Sphagnum subsecundum and feathermosses (Hylocomium splendens and Pleurozium schreberi) have a higher capacity to absorb phosphate than do the fine roots of black spruce (Picea mariana) that are situated beneath the moss layer. In three of the four moss species studied, phosphate absorption capacity increases with increasing age of green tissue and decreases with increasing age of brown tissue. In the two feathermosses, which acquire moisture primarily from the air, and in Sphagnum, phosphate absorption is more rapid in green than in brown tissue. In contrast, the endohydric moss Polytrichum commune, which transports water through stem tissue from soil, absorbs phosphate most rapidly from stems in mineral soil. Two treatments designed to reduce activity of mycorrhizae (cutting of roots extending beneath the moss carpet or application to the moss surface of a fungicide that kills mycorrhizal hyphae) tended to increase phosphate retention by mosses and reduce phosphate transfer out of the experimental plots. This suggests that mycorrhizae are an important avenue of phosphorus movement out of the moss carpet and a means by which the black spruce competes with the overlying mosses for nutrients.
We have utilized the Spitzer Space Telescope (SST) Infrared Spectrograph (IRS) to directly observe thermal emission from the nucleus of comet 9P/Tempel 1 on UT 2004 March 25-27. We obtained 8-35 km ...low-resolution (R 6 100) spectra and contemporaneous 16 and 22 km photometric imaging over a 39 hr period. The comet was 3.7 AU from the Sun at the time, approximately 464 days before perihelion on 2005 July 5, and showed no evidence of extended emission beyond a point source. Visual inspection of the absolute photometry implies a rotation period of 40 c 2 hr, consistent with earlier results. Snapshot photometry by Spitzer at 8 and 24 km, taken on UT 2004 March 10 and 15, respectively, are consistent with this light-curve phasing and with the IRS-measured flux. The spectra agree well with the predictions of the standard thermal model for a slowly rotating body with thermal inertia between 0 and 50 J K super(-1) m super(-2) s super(-1/2), and are inconsistent with any rapid rotator model. The mean effective radius at the middle of the light curve is 3.3 c 0.2 km. The maximum-to-minimum flux ratio of 1.8 in the light curve is consistent with an axial ratio a/b of 3.2 c 0.4, implying a = 7.2 c 0.9 km and b = 2.3 c 0.3 km. Combining our SST infrared light curve with visible observations of the nucleus, we obtain a visible geometric albedo of 0.04 c 0.01. With this sized nucleus and the published water production rates, we estimate that 9% c 2% of the surface area is actively emitting volatile material at perihelion.
Changes in foliar chemistry resulting from changes in forest-floor and mineral-soil moisture availability, forest-floor microbial energy supply, and nitrogen availability were investigated across the ...successional sequences in both upland and floodplain landscape positions. Three amendments, sugar, sawdust, and nitrogen fertilizer $(NH_4NO_3)$ were applied to a series of three upland and four floodplain successional sites. The sugar and sawdust treatments were designed to increase the carbon: nitrogen ratio (C/N) of the forest floor to values typical of black spruce sites $(C/N = 50)$. The nitrogen fertilizer treatment was designed to equal estimated yearly N mineralization in an attempt to double available nitrogen in the forest floor. A moisture exclusion treatment was designed to remove all summer rainfall from the treatment plots. Foliar phosphorus concentrations were higher in the upland sites than on the floodplain. No consistent differences were reported among successional stages within a landscape unit. The effect of either sugar or sawdust treatment was to decrease foliar phosphorus concentrations. Sugar produced more significant differences than did sawdust. Sugar treatments decreased foliar nitrogen in all tree species except for white spruce, while fertilizer tended to increase foliar nitrogen. In the second year following treatment there was not an increase in foliar nitrogen concentration resulting from fertilizer treatment.
Modern medical education requires frequent competency assessment. The Accreditation Council for Graduate Medical Education (ACGME) provides a descriptive framework of competencies and milestones but ...does not provide standardized instruments to assess and track trainee competency over time. Entrustable professional activities (EPAs) represent a workplace-based method to assess the achievement of competency milestones at the point-of-care that can be applied to anesthesiology training in the United States.
Experts in education and competency assessment were recruited to participate in a 6-step process using a modified Delphi method with iterative rounds to reach consensus on an entrustment scale, a list of EPAs and procedural skills, detailed definitions for each EPA, a mapping of the EPAs to the ACGME milestones, and a target level of entrustment for graduating US anesthesiology residents for each EPA and procedural skill. The defined EPAs and procedural skills were implemented using a website and mobile app. The assessment system was piloted at 7 anesthesiology residency programs. After 2 months, faculty were surveyed on their attitudes on usability and utility of the assessment system. The number of evaluations submitted per month was collected for 1 year.
Participants in EPA development included 18 education experts from 11 different programs. The Delphi rounds produced a final list of 20 EPAs, each differentiated as simple or complex, a defined entrustment scale, mapping of the EPAs to milestones, and graduation entrustment targets. A list of 159 procedural skills was similarly developed. Results of the faculty survey demonstrated favorable ratings on all questions regarding app usability as well as the utility of the app and EPA assessments. Over the 2-month pilot period, 1636 EPA and 1427 procedure assessments were submitted. All programs continued to use the app for the remainder of the academic year resulting in 12,641 submitted assessments.
A list of 20 anesthesiology EPAs and 159 procedural skills assessments were developed using a rigorous methodology to reach consensus among education experts. The assessments were pilot tested at 7 US anesthesiology residency programs demonstrating the feasibility of implementation using a mobile app and the ability to collect assessment data. Adoption at the pilot sites was variable; however, the use of the system was not mandatory for faculty or trainees at any site.
The coronavirus disease 2019 (COVID-19) pandemic has significantly affected children and families. The study purpose was to better understand the perceptions of pediatric-focused advanced practice ...registered nurses (P-APRNs) on the impact of COVID-19 on patients and practice.
A 25-item electronic survey including Likert scales, multiple choice , and open-ended questions was sent by e-mail to electronic mailing list of the National Association of Pediatric Nurse Practitioners.
Responses (N = 109) reflect the magnitude of challenges affecting child physical health, mental health, parental stress, and social determinants of health. P-APRNs expect greater refusal of the COVID-19 vaccine compared with other vaccines. Telehealth use continues at an increased rate and greater resources are needed to support clinical practice.
The COVID-19 pandemic has transformed the lives of children, families, and P-APRN practice. These findings reflect challenges and opportunities moving forward. P-APRNs are well-prepared to lead change to support better and more equitable outcomes for all.
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