1,766 research outputs found
Mapping Complex Urban Land Cover from Spaceborne Imagery: The Influence of Spatial Resolution, Spectral Band Set and Classification Approach
Detailed land cover information is valuable for mapping complex urban environments. Recent enhancements to satellite sensor technology promise fit-for-purpose data, particularly when processed using contemporary classification approaches. We evaluate this promise by comparing the influence of spatial resolution, spectral band set and classification approach for mapping detailed urban land cover in Nottingham, UK. A WorldView-2 image provides the basis for a set of 12 images with varying spatial and spectral characteristics, and these are classified using three different approaches (maximum likelihood (ML), support vector machine (SVM) and object-based image analysis (OBIA)) to yield 36 output land cover maps. Classification accuracy is evaluated independently and McNemar tests are conducted between all paired outputs (630 pairs in total) to determine which classifications are significantly different. Overall accuracy varied between 35% for ML classification of 30 m spatial resolution, 4-band imagery and 91% for OBIA classification of 2 m spatial resolution, 8-band imagery. The results demonstrate that spatial resolution is clearly the most influential factor when mapping complex urban environments, and modern âvery high resolutionâ or VHR sensors offer great advantage here. However, the advanced spectral capabilities provided by some recent sensors, coupled with contemporary classification approaches (especially SVMs and OBIA), can also lead to significant gains in mapping accuracy. Ongoing development in instrumentation and methodology offer huge potential here and imply that urban mapping opportunities will continue to grow
Metallocene to metallocene conversion. Synthesis of an oxazoline-substituted pentamethyliridocenium cation from a ferrocenyloxazoline
Reaction of (S)-2-ferrocenyl-4-(1-methylethyl)oxazoline with [(CpIrCl2)-Ir-star](2) in benzonitrile with KPF6 and NaOH gave (eta(5)-(S)-2-(4-(1-methylethyl))oxazolinylcyclopentadienyl)(eta(5)-pentamethylcyclopentadienyl)-iridium(III) hexafluorophosphate (68%). This transformation of an iron-based into an iridium-based metallocene proceeds via the rearrangement, with loss of cyclopentadienyliron, of an intermediate cationic ferrocenyliridacycle
Use of Auto-Germ to Model Germination Timing in the Sagebrush-Steppe
Germination timing has a strong influence on direct seeding efforts, and therefore is a closely tracked demographic stage in a wide variety of wildland and agricultural settings. Predictive seed germination models, based on soil moisture and temperature data in the seed zone are an efficient method of estimating germination timing. We utilized Visual Basic for Applications (VBA) to create AutoâGerm, which is an Excel workbook that allows a user to estimate field germination timing based on wetâthermal accumulation models and field temperature and soil moisture data. To demonstrate the capabilities of AutoâGerm, we calculated various germination indices and modeled germination timing for 11 different species, across 6 years, and 10 Artemisiaâsteppe sites in the Great Basin of North America to identify the planting date required for 50% or more of the simulated population to germinate in spring (1 March or later), which is when conditions are predicted to be more conducive for plant establishment. Both between and within the species, germination models indicated that there was high temporal and spatial variability in the planting date required for spring germination to occur. However, some general trends were identified, with species falling roughly into three categories, where seeds could be planted on average in either fall (Artemisia tridentata ssp. wyomingensis and Leymus cinereus), early winter (Festuca idahoensis, Poa secunda, Elymus lanceolatus, Elymus elymoides, and Linum lewisii), or midâwinter (Achillea millefolium, Elymus wawawaiensis, and Pseudoroegneria spicata) and still not run the risk of germination during winter. These predictions made through AutoâGerm demonstrate that fall may not be an optimal time period for sowing seeds for most nonâdormant species if the desired goal is to have seeds germinate in spring
Human Spotted Fever Rickettsial Infections
Serum specimens from patients at 4 sites in Peru were tested for evidence of spotted fever group rickettsial infection. Results showed that 30 (18%) of 170 patients had spotted fever group rickettsial infections, which likely caused their illnesses. These findings document laboratory-confirmed spotted fever from diverse areas of Peru
Search for proton decay via pâÎŒ+K0 in 0.37 megaton-years exposure of Super-Kamiokande
We searched for proton decay via pâÎŒ+K0 in 0.37ââMtonâ
years of data collected between 1996 and 2018 from the Super-Kamiokande water Cherenkov experiment. The selection criteria were defined separately for
K0S and K0L channels. No significant event excess has been observed. As a result of this analysis, which extends the previous search by an additional 0.2ââMtonâ
years of exposure and uses an improved event reconstruction, we set a lower limit of 3.6Ă1033ââyears on the proton lifetime
Impact of a Professional Identity Formation Program on Student Perceptions
In response to the call for reform in professional identity formation (PIF) (OâBrien & Irby, 2013), the University of Utah pioneered a program called RealMD which utilizes coaching and group self-discovery activities to encourage purpose and community in preparation for studentsâ future medical careers (Cruess, Cruess, Boudreau, Snell, & Steinert, 2014). The program focuses on 15 attitudes/skills central to identity development (Tsai, Moniz, Davis, & Chang, 2017). In this study, we explored the impact of the program on student self-perceptions.
We administered a retrospective, pre-post survey at the end of year to students (n=253), in which 111 (44%) rated perceived importance of each attitude/skill at the start and end of the year. The survey also allowed open-ended comments. Analyzing the mean gain in ratings across the 2 time periods, 14 of the 15 items increased (range =.01 to .37), with a significant (p<0.05) increase on 4 items (applying identity development to career, having a self-reflection process, creating a networking plan, and identifying an issue in healthcare to change). Comments corroborated the notable impact of being a student in the program on said attitudes/skills
Factors influencing implementation of team-based learning in health sciences education
Abstract Background Limited studies have looked at factors that lead to successful implementation of team-based learning (TBL). The purpose of this study was to identify contextual factors associated with implementation of TBL with a larger pool of individuals
Search for astrophysical electron antineutrinos in Super-Kamiokande with 0.01% Gadolinium-loaded water
We report the first search result for the flux of astrophysical electron antineutrinos for energies in the gadolinium-loaded Super-Kamiokande (SK) detector. In 2020 June, gadolinium was introduced to the ultrapure water of the SK detector in order to detect neutrons more efficiently. In this new experimental phase, SK-Gd, we can search for electron antineutrinos via inverse beta decay with efficient background rejection thanks to the high efficiency of the neutron tagging technique. In this paper, we report the result for the initial stage of SK-Gd, during 2020 August 26, and 2022 June 1 with a 22.5 à 552 kton · day exposure at 0.01% Gd mass concentration. No significant excess over the expected background in the observed events is found for the neutrino energies below 31.3 MeV. Thus, the flux upper limits are placed at the 90% confidence level. The limits and sensitivities are already comparable with the previous SK result with pure water (22.5 à 2970 kton · day) owing to the enhanced neutron tagging. Operation with Gd increased to 0.03% started in 2022 June
Age as a Predictor for Complications and Patient-reported Outcomes in Multilevel Transforaminal Lumbar Interbody Fusions: Analyses From the Michigan Spine Surgery Improvement Collaborative (MSSIC)
STUDY DESIGN: Retrospective review of a multi-institutional data registry.
OBJECTIVE: The authors sought to determine the association between age and complications & patient-reported outcomes (PRO) in patients undergoing multilevel transforaminal interbody lumbar fusion (MTLIF).
SUMMARY OF BACKGROUND DATA: Elderly patients undergoing MTLIF are considered high risk. However, data on complications and PRO are lacking. Additionally, safety of multilevel lumbar fusion in the elderly remains uncertain.
METHODS: Patients â„50-year-old who underwent MTLIF for degenerative lumbar spine conditions were analyzed. Ninety-day complications and PROs (baseline, 90-d, 1-y, 2-y) were queried using the MSSIC database. PROs were measured by back & leg visual analog scale (VAS), Patient-reported Outcomes Measurement Information System (PROMIS), EuroQol-5D (EQ-5D), and North American Spine Society (NASS) Patient Satisfaction Index. Univariate analyses were used to compare among elderly and complication cohorts. Generalized estimating equation (GEE) was used to identify predictors of complications and PROs.
RESULTS: A total of 3120 patients analyzed with 961 (31%) â„ 70-y-o and 2159 (69%) between 50-69. A higher proportion of elderly experienced postoperative complications (Pâ=â.003) including urinary retention (Pâ=â\u3c.001) and urinary tract infection (Pâ=â.002). Multivariate analysis demonstrated that age was not independently associated with complications. Number of operative levels was associated with any (Pâ=â.001) and minor (Pâ=â.002) complication. Incurring a complication was independently associated with worse leg VAS and PROMIS scores (Pâ=â\u3c.001). Preoperative independent ambulation was independently associated with improved PROMIS, and EQ5D (Pâ=â\u3c.001). Within the elderly, preoperative independent ambulation and lower BMI were associated with improved PROMIS (Pâ=â\u3c.001). Complications had no significant effect on PROs in the elderly.
CONCLUSIONS: Age was not associated with complications nor predictive of functional outcomes in patients who underwent MTLIF. Age alone, therefore, may not be an appropriate surrogate for risk. Furthermore, baseline preoperative independent ambulation was associated with better clinical outcomes and should be considered during preoperative surgical counseling.
Level of Evidence: 3
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