scholarly journals Mitigation of Geostationary Lightning Mapper Geolocation Errors

2020 ◽  
Vol 37 (9) ◽  
pp. 1725-1736
Author(s):  
Katrina S. Virts ◽  
William J. Koshak
Keyword(s):  
Optical Sensors ◽  
A Priori ◽  
First Year ◽  
Location Accuracy ◽  
Location Errors ◽  
Geostationary Operational Environmental Satellite ◽  
Ellipsoidal Surface ◽  
Reference Networks ◽  
Peak Location

AbstractThe geolocation of lightning flashes observed by spaceborne optical sensors depends upon a priori assumptions of the cloud-top height (or, more generally, the height of the radiant emitter) as observed by the satellite. Lightning observations from the Geostationary Lightning Mappers (GLMs) on Geostationary Operational Environmental Satellite 16 (GOES-16) and GOES-17 were originally geolocated by assuming that the global cloud-top height can be modeled as an ellipsoidal surface with an altitude of 16 km at the equator and sloping down to 6 km at the poles. This method produced parallax errors of 20–30 km or more near the limb, where GLM can detect side-cloud illumination or below-cloud lightning channels at lower altitudes than assumed by the ellipsoid. Based on analysis of GLM location accuracy using a suite of alternate lightning ellipsoids, a lower ellipsoid (14 km at the equator, 6 km at the poles) was implemented in October and December 2018 for GLM-16 and GLM-17, respectively. While the lower ellipsoid slightly improves overall GLM location accuracy, parallax-related errors remain, particularly near the limb. This study describes the identification of optimized assumed emitter heights, defined as those that produce the closest agreement with the ground-based reference networks. Derived using the first year of observations from GOES-East position, the optimal emitter height varies geographically and seasonally in a manner consistent with known meteorological regimes. Application of the optimal emitter height approximately doubles the fraction of area near the limb for which peak location errors are less than half a GLM pixel.

scholarly journals Hermann Weyl, 1885-1955

1957 ◽  
Vol 3 ◽  
pp. 305-328 ◽  
Keyword(s):  
Galois Theory ◽  
A Priori ◽  
First Year ◽  
Critique Of Pure Reason ◽  
Elementary Number Theory ◽  
Foundations Of Geometry ◽  
Summer Vacation ◽  
Classical Work ◽  
Hermann Weyl ◽  
Kantian Philosophy

Hermann Weyl was born on 9 November 1885, the son of Ludwig and Anna Weyl, in the small town of Elmshorn near Hamburg. When his schooldays in Altona ended in 1904 he entered Göttingen University as a country lad of eighteen, and there remained (except for a year at Munich), first as student and then as Privatdozent, until his call to Zurich in 1913. Of these days he said (in the obituary of Hilbert for this Society, 1944), ‘Hilbert and Minkowski were the real heroes of the great and brilliant period which mathematics experienced during the first decade of the century in Göttingen, unforgettable to those who lived through it. Klein ruled over it like a distant god, “divus Felix”, from above the clouds.’ Among those nearer to his own age whom he found there were Carathéodory and Harald Bohr, Courant, Zermelo, Erhard Schmidt. While still a schoolboy he had picked up in his father’s house an old copy of the Critique of Pure Reason, and absorbed with enthusiasm Kant’s thesis of the a priori nature of Euclidean geometry. But in Göttingen Hilbert had just completed his classical work on the foundations of geometry, with its host of strange ‘counter’-geometries. Kantian philosophy could not survive this blow: Weyl transferred his allegiance to Hilbert. ‘I resolved to study whatever this man had written. At the end of my first year I went home with the “Zahlbericht” under my arm, and during the summer vacation I worked my way through it—without any previous knowledge of elementary number theory or Galois theory. These were the happiest months of my life, whose shine, across years burdened with our common share of doubt and failure, still comforts my soul.’ (133, 1944.)

Correlation filters minimizing peak location errors

1992 ◽  
Vol 9 (5) ◽  
pp. 678 ◽  
Author(s):  
B. V. K. Vijaya Kumar ◽  
Fred M. Dickey ◽  
John M. DeLaurentis
Keyword(s):  
Correlation Filters ◽  
Location Errors ◽  
Peak Location

Abstract P73: Social Support and Adherence to Cardiac Risk Factor Management Instructions during the First Year after Acute Myocardial Infarction

2011 ◽  
Vol 4 (suppl_1) ◽  
Author(s):  
Erica C Leifheit-Limson ◽  
Kimberly J Reid ◽  
Stanislav V Kasl ◽  
Haiqun Lin ◽  
Philip G Jones ◽  
...  
Keyword(s):  
Social Support ◽  
Risk Factor ◽  
Repeated Measures ◽  
Diabetes Management ◽  
A Priori ◽  
Clinical History ◽  
Poor Adherence ◽  
Cardiac Risk Factor ◽  
First Year ◽  
Risk Factor Management

Background: Adherence to risk factor management (RFM) instructions after AMI can promote recovery. The prognostic importance of social support for adherence is not well understood. We examined the relationship between baseline social support and post-AMI RFM adherence, and tested whether depression moderates this association. Methods: Using data from 2202 AMI patients enrolled in the 19-site PREMIER study, we longitudinally examined whether low baseline social support (index hospitalization; score <=18 on 5 items from ENRICHD Social Support Inventory) is associated with poor adherence to 13 RFM instructions (medication adherence, warfarin use, follow-up plan/appointments, whom to call, cholesterol monitoring and therapy, diabetes management, weight monitoring and loss, smoking cessation, diet, exercise, cardiac rehabilitation) within the first year of recovery. Patients were asked at 1, 6, and 12 months if they received any of the RFM instructions since their last interview. Poor adherence was defined a priori as adhering “very carefully” to less than 50% of the patient-appropriate instructions. Hierarchical repeated-measures Poisson regression evaluated the association between support and adherence, with adjustment for site, sociodemographics, clinical history and presentation, hospital and outpatient care, and depression. Whether depression (PHQ-9 score >=10) modified the association was evaluated by stratifying the risk-adjusted model by depression status and including a support*depression interaction term. Results: Patients with low social support had greater unadjusted risk of poor adherence than patients with high social support (RR 1.46, 95% CI 1.27-1.67). This association did not vary with time and remained significant after full risk adjustment (RR 1.24, 95% CI 1.05-1.47). In depression-stratified analyses, the risk-adjusted association of low support with poor adherence was significant among nondepressed (RR 1.44, 95% CI 1.26-1.66) but not depressed (RR 1.03, 95% CI 0.79-1.33) patients (p<0.001 for support*depression interaction). Conclusion: Good social support may improve adherence among nondepressed AMI patients, but more research is needed to understand the role of social support among depressed patients.

scholarly journals Role Ambiguity in Sport Teams

2003 ◽  
Vol 25 (4) ◽  
pp. 534-550 ◽  
Author(s):  
Mark A. Eys ◽  
Albert V. Carron ◽  
Mark R. Beauchamp ◽  
Steven R. Bray
Keyword(s):  
Role Ambiguity ◽  
A Priori ◽  
Operational Definition ◽  
General Purpose ◽  
Future Research ◽  
First Year ◽  
Individual Level ◽  
Sport Teams ◽  
Definition Of ◽  
The Individual

The general purpose of the present study was to examine the nature of role ambiguity in sport teams and to explore the construct validity of the operational definition of role ambiguity developed by Beauchamp, Bray, Eys, and Carron (2002). Role ambiguity was operationalized as a multidimensional construct (Scope of Responsibilities, Behavioral Responsibilities, Evaluation of Performance, and Consequences of Not Fulfilling Responsibilities) that occurs in two contexts, offense and defense. Consistent with the a priori hypothesis, perceptions of role ambiguity exhibited some degree of within-group consistency and group-level variability, but most of the variance in role ambiguity was seen at the individual level. Also, perceptions of role ambiguity decreased from early to late season. Finally, veteran athletes experienced less role ambiguity than first-year athletes at the beginning of the season, but not at the end. Implications of the findings and suggestions for future research are discussed.

scholarly journals Sensitivity maps for time-reverse imaging: an accuracy study for the Los Humeros Geothermal Field (Mexico)

2020 ◽  
Vol 222 (1) ◽  
pp. 231-246
Author(s):  
C Finger ◽  
E H Saenger
Keyword(s):  
A Priori ◽  
Velocity Model ◽  
Source Location ◽  
Geothermal Field ◽  
Location Accuracy ◽  
Accurate Localization ◽  
Localization Scheme ◽  
Priori Information ◽  
Initial Source ◽  
Sensitivity Maps

SUMMARY The estimation of the source–location accuracy of microseismic events in reservoirs is of significant importance. Time-reverse imaging (TRI) provides a highly accurate localization scheme to locate events by time-reversing the recorded full wavefield and back propagating it through a velocity model. So far, the influence of the station geometry and the velocity model on the source–location accuracy is not well known. Therefore, sensitivity maps are developed using the geothermal site of Los Humeros in Mexico to evaluate the spatial variability of the source–location accuracy. Sensitivity maps are created with an assumed gradient velocity model with a constant vp–vs ratio and with a realistic velocity model for the region of Los Humeros. The positions of 27 stations deployed in Los Humeros from September 2017 to September 2018 are used as surface receivers. An automatic localization scheme is proposed that does not rely on any a priori information about the sources and thus negates any user bias in the source locations. The sensitivity maps are created by simulating numerous uniformly distributed sources simultaneously and locating these sources using TRI. The found source locations are compared to the initial source locations to estimate the achieved accuracy. The resulting sensitivity maps show that the station geometry introduces complex patterns in the spatial variation of accuracy. Furthermore, the influence of the station geometry on the source–location accuracy is larger than the influence of the velocity model. Finally, a microearthquake recorded at the geothermal site of Los Humeros is located to demonstrate the usability of the derived sensitivity maps. This study stresses the importance of optimizing station networks to enhance the accuracy when locating seismic events using TRI.

Evaluation of the Preterm Infant for Patent Ductus Arteriosus

PEDIATRICS ◽  
1983 ◽  
Vol 71 (3) ◽  
pp. 364-372 ◽  
Author(s):  
R. Curtis Ellison ◽  
George J. Peckham ◽  
Peter Lang ◽  
Norman S. Talner ◽  
Trudy J. Lerer ◽  
...  
Keyword(s):  
Birth Weight ◽  
Patent Ductus Arteriosus ◽  
Marked Decrease ◽  
Ductus Arteriosus ◽  
A Priori ◽  
First Year ◽  
Collaborative Project ◽  
False Positive Diagnosis ◽  
Patent Ductus

As a first step in a multicenter, collaborative project to study the role of indomethacin in the management of patent ductus arteriosus in premature infants, a diagnostic scheme was developed, on an a priori basis, by a consensus of the participating neonatologists and pediatric cardiologists. The scheme, which utilizes clinical and noninvasive findings, was designed to detect infants with a "hemodynamically significant" patent ductus arteriosus (PDA). Among 1,689 infants with birth weight less than 1,750 g who were monitored during the first year of the study, 342 (20.2%) met the criteria for PDA. Rates were higher for smaller infants (42% with birth weight &lt;1,000 g) than for larger infants (7% with birth weight 1,500 to 1,750 g). Although study protocol did not require a direct procedure to confirm the diagnosis of PDA, a marked decrease in the presence of most criteria was noted following surgical ligation of the ductus. Although the echocardiographic criterion (ratio of left atrium to aorta [LA/Ao]≥1.15) proved to have a low specificity for PDA, the data suggest that the overall scheme led to a very low rate of false-positive diagnosis. Following the application of the scheme for 1 year at 13 clinical centers, it has been shown to be a highly acceptable means of detecting infants with PDA.

scholarly journals Integrating clinical reasoning principles in case-based learning sessions for first-year medical students: Lessons learned

2019 ◽  
Vol 8 (1) ◽  
pp. 20-23
Author(s):  
Dinesh Kumar ◽  
Ramakrishnan Rajprasath ◽  
Magi Murugan
Keyword(s):  
Medical Education ◽  
Medical Students ◽  
Clinical Reasoning ◽  
A Priori ◽  
Lessons Learned ◽  
First Year ◽  
Perceived Acceptance ◽  
Case Based Learning ◽  
First Year Medical Students ◽  
Case Based

Background: Conventional pedagogies for case-based learning are designed with the intention of helping the student appreciate the relevance of content they learn and kindle their curiosity. However, these pedagogies embody certain shortcomings which inhibit them from reaching the intended objectives. The main aim of our initiative is to improve traditional case-based learning using the principles of clinical reasoning. Methods: A priori, two sessions were conducted in which two vignettes were administered to first-year medical students. We obtained the perceived acceptance which was equivalent to Kirkpatrick level 1 learning outcomes. Results: Overall outcomes were highly positive in terms of acceptability, fostering curiosity, increasing the relevance of learned content, and helping students learn to think in a logical way. Conclusion: With the increasing need for incorporating clinical reasoning skills in medical education, it is imperative that these skills are taught beginning with the preclinical years of medical education.

scholarly journals Research skills in the first-year biology practical - Are they there?

2018 ◽  
Vol 15 (4) ◽  
pp. 32-55
Author(s):  
Lyn Torres
Keyword(s):  
A Priori ◽  
First Year ◽  
Metacognitive Skills ◽  
Research Skills ◽  
Student Preparedness ◽  
Laboratory Manual ◽  
Learning And Teaching ◽  
Qualitative Research Design ◽  
Fundamental Research ◽  
Pedagogical Models

Laboratory practicals engage students in complex thinking to build their scientific knowledge and understanding. Surprisingly few studies connect the development of students’ cognitive and metacognitive skills for learning in the laboratory practical with foundational skills for researching. Librarians strive to establish teaching partnerships with academics to contextualise research skills within curriculum content. However, pedagogical models to make research skills explicit and guide libraryfaculty collaborations are lacking. This study explores the Research Skill Development (RSD) framework (Willison & O'Regan 2006/2018; see the first article in this issue) to extrapolate students’ research skills in a first-year biology practical unit. A qualitative research design was applied to identify research skills in the unit’s laboratory manual and in descriptive observations of students in five laboratory practicals. Results show students engaged in the research skills articulated by the RSD, yet these skills were implied rather than explicitly taught. Implications suggest that fundamental research skills which enable student preparedness for research can be overlooked in practical curricula. Research skills remaining unrecognised impacts learning and teaching, including the contribution librarians could make in this context. Findings demonstrated that the RSD is a useful theoretical construct and a priori framework to make research skills visible to educators.

scholarly journals Constructing mental diagrams during problem-solving in mathematics

Pythagoras ◽  
2021 ◽  
Vol 42 (1) ◽  
Author(s):  
Vimolan Mudaly
Keyword(s):  
Problem Solving ◽  
A Priori ◽  
Real Life ◽  
First Year ◽  
Mental Images ◽  
Problem Solving Skills ◽  
Mathematics Problem Solving ◽  
Life Issues ◽  
Problem Solving Process ◽  
The Given

In mathematics, problem-solving can be considered to be one of the most important skills students need to develop, because it allows them to deal with increasingly intricate mathematical and real-life issues. Often, teachers attempt to try to link a problem with a drawn diagram or picture. Despite these diagrams, whether given or constructed, the student still individually engages in a private discourse about the problem and its solution. These discourses are strongly influenced by their a priori knowledge and the given information in the problem itself. This article explores first-year pre-service teachers’ mental problem-solving skills. The emphasis was not on whether they solved the problems, but rather on their natural instincts during the problem-solving process. The research shows that some students were naturally drawn to construct mental images during the problem-solving process while others were content to simply leave the question blank. The data were collected from 35 first-year volunteer students attending a second semester geometry module. The data were collected using task sheets on Google Forms and interviews, which were based on responses to the questions. An interpretive qualitative analysis was conducted in order to produce deeper meaning (insight). The findings point to the fact that teachers could try to influence how students think during the problem-solving process by encouraging them to engage with mental images.

Sign in / Sign up

Export Citation Format

Share Document